Electrode assembly, battery, and battery pack and automobile comprising the same

Abstract

Disclosed are an electrode assembly, a battery, a battery pack including the same, and an automobile. In the electrode assembly, a first electrode, a second electrode, and a separator film interposed therebetween are wound about a winding axis to define a core portion and an outer circumferential surface, the first electrode including, in a winding direction, a first active material portion coated with an active material layer and a first uncoated portion not coated with the active material layer. At least a portion of the first uncoated portion is defined as an electrode tab by itself. The first uncoated portion can include a first portion adjacent to the core portion of the electrode assembly, a second portion adjacent to the outer circumferential surface of the electrode assembly, and a third portion between the first portion and the second portion. In the direction of the winding axis, the first portion or the second portion has a lower height than the third portion.

Description

Technical Field

[0001] This invention relates to electrode assemblies, batteries, battery packs containing the same, and automobiles. Background Technology

[0002] In addition to portable devices, secondary batteries, which are easy to use and have high energy density and other electrical properties, are also widely used in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electric drive sources.

[0003] Such secondary batteries not only have the primary advantage of significantly reducing the use of fossil fuels, but also the advantage of not producing any byproducts when using energy. Therefore, they are attracting much attention as a new energy source that is both environmentally friendly and improves energy efficiency.

[0004] Currently, widely used rechargeable batteries include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries. The operating voltage of a single rechargeable battery, or a single cell, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, multiple batteries are sometimes connected in series to form a battery pack. Furthermore, depending on the required charge / discharge capacity of the battery pack, multiple batteries are sometimes connected in parallel to form a battery pack. Therefore, depending on the required output voltage and / or charge / discharge capacity, the number of batteries included in the above-mentioned battery packs and the electrical connection method can be designed in various ways.

[0005] On the other hand, as types of unit secondary batteries, cylindrical, square, and pouch batteries are disclosed. Cylindrical batteries have a separator membrane, serving as an insulator, sandwiched between the anode and cathode, and this membrane is rolled up to form a gel-roll-shaped electrode assembly, which is then inserted into the battery casing to form the battery. In this field, the battery casing is referred to as a battery can. Furthermore, the uncoated portions of the anode and cathode can be connected to strip electrode tabs, which electrically connect the electrode assembly to the exposed electrode terminals. For reference, the anode electrode terminal is a cover for sealing the opening of the battery casing, and the cathode electrode terminal is the battery casing itself. However, according to existing cylindrical batteries with this structure, the current concentrates at the strip electrode tabs connected to the uncoated portions of the anode and / or the uncoated portions of the cathode, resulting in high resistance, excessive heat generation, and low current collection efficiency.

[0006] For small cylindrical batteries with form factors of 1865 (diameter: 18mm, height: 65mm) or 2170 (diameter: 21mm, height: 70mm), resistance and heat generation are not major issues. However, when the form factor is increased to accommodate cylindrical batteries in electric vehicles, significant heat is generated around the electrode tabs during fast charging, potentially leading to battery fires.

[0007] To address this issue, a cylindrical battery with an improved current-collecting efficiency (a so-called tabless cylindrical battery) has been disclosed. The battery is designed with an uncoated anode and an uncoated cathode located at the upper and lower ends of a gel roll-type electrode assembly, respectively, and the current collector is welded to such uncoated portions.

[0008] Figures 1 to 3 This is a diagram illustrating the manufacturing process of a tabless cylindrical battery. Figure 1 The structure of the electrode is shown. Figure 2 The electrode winding process is shown. Figure 3 The process of welding a current collector to the bent surface area of ​​the uncoated portion is shown.

[0009] Reference Figures 1 to 3 The anode 10 and cathode 11 have a structure in which an active material 21 is coated on the sheet current collector 20, and along the winding direction X, an uncoated portion 22 is included on one long side. The long side refers to the side with a longer length in the direction parallel to the x-axis.

[0010] like Figure 2 As shown, electrode assembly A is manufactured by sequentially stacking the anode 10 and cathode 11 together with two separation membranes 12 and then winding them in one direction X. At this time, the uncoated portions of the anode 10 and cathode 11 are arranged in opposite directions.

[0011] After the winding process, the uncoated portion 10a of the anode 10 and the uncoated portion 11a of the cathode 11 are bent toward the core. Then, the current collectors 30 and 31 are welded to the uncoated portions 10a and 11a respectively to achieve bonding.

[0012] No other electrode tabs are attached to the uncoated anode portion 10a and the uncoated cathode portion 11a. The current collectors 30 and 31 are connected to external electrode terminals, forming a current path with a large cross-sectional area along the winding axis direction of the electrode assembly A (refer to the arrow). Therefore, it has the advantage of reducing battery resistance. This is because resistance is inversely proportional to the cross-sectional area of ​​the current flow path.

[0013] In tabless cylindrical batteries, in order to improve the welding characteristics of uncoated portions 10a and 11a and current collectors 30 and 31, it is necessary to apply strong pressure to the welding area of ​​uncoated portions 10a and 11a to bend the uncoated portions 10a and 11a as flat as possible.

[0014] However, when bending the welding areas of the uncoated portions 10a and 11a, their shapes may become irregularly skewed and deformed. In this case, the deformed portion may come into contact with an electrode of opposite polarity, potentially causing an internal short circuit or inducing microcracks in the uncoated portions 10a and 11a. Furthermore, bending the uncoated portion 32 adjacent to the core of electrode assembly A may block all or most of the cavity 33 located in the core of electrode assembly A. In this case, problems arise during the electrolyte injection process. That is, the cavity 33 located in the core of electrode assembly A is used as a channel for injecting electrolyte. However, if the corresponding channel is blocked, it is difficult to inject electrolyte. Moreover, during the insertion of the electrolyte injector into the cavity 33, interference may occur with the uncoated portion 32 near the core, potentially causing the uncoated portion 32 to tear.

[0015] Furthermore, the bent portions of the uncoated parts 10a and 11a used for welding current collectors 30 and 31 need to be overlapped in multiple layers, without any gaps. Only in this way can sufficient weld strength be obtained, and even when using the latest technologies such as laser welding, the problem of laser penetration into the electrode assembly A and melting the separation film or active material can be prevented.

[0016] On the other hand, existing tabless cylindrical batteries have an uncoated anode portion 10a integrally formed on the upper part of the electrode assembly A. Therefore, when the outer peripheral surface of the upper end of the battery casing is pressed inward to form a beading portion, the upper edge region 34 of the electrode assembly A is subjected to pressure from the battery casing. Such pressure may cause localized deformation of the electrode assembly A, which could tear the separation membrane 12 and potentially cause an internal short circuit. If a short circuit occurs inside the battery, it could lead to overheating or an explosion. Summary of the Invention

[0017] The technical problem that the invention aims to solve

[0018] The present invention was made in the context of the prior art as described above, and its object is to provide an electrode assembly having an uncoated portion structure that can alleviate the stress pressure applied to the uncoated portion when the uncoated portion exposed at both ends of the electrode assembly is bent.

[0019] Another technical problem of the present invention is to provide an electrode assembly that will not be blocked even if the uncoated part is bent.

[0020] Another technical problem of the present invention is to provide an electrode assembly having a structure that prevents the upper edge of the electrode assembly from contacting the inner surface of the battery housing when the upper end of the battery housing is rolled in.

[0021] Another technical problem of the present invention is to provide an electrode assembly that applies a stencil structure to the uncoated portion of the electrode and optimizes the dimensions (width, height, spacing) of the stencils to sufficiently increase the number of stencil layers used as the welding target area, thereby improving the physical properties of the welding area.

[0022] Another technical problem of the present invention is to provide an electrode assembly that improves energy density and reduces resistance by welding a large area current collector in a structure formed by bending multiple segments to a bent surface area.

[0023] Another technical problem of the present invention is to provide a battery that includes terminals and current collectors with improved design to enable electrical wiring to be performed on the upper part.

[0024] Another technical problem of the present invention is to provide a battery including an electrode assembly with an improved structure, a battery pack including the battery, and a vehicle including the battery pack.

[0025] The technical problem to be solved by the present invention is not limited to the above-mentioned technical problem. Those skilled in the art will clearly understand other technical problems not mentioned through the invention description below.

[0026] means of solving technical problems

[0027] According to the electrode assembly of the present invention for achieving the above-mentioned technical problems, a first electrode, a second electrode, and a separation membrane sandwiched therebetween are wound around a winding axis to define a core and an outer peripheral surface. In the electrode assembly, the first electrode includes, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. At least a portion of the first uncoated portion is defined as an electrode tab in itself. The first uncoated portion includes a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer peripheral surface of the electrode assembly, and a third portion between the first portion and the second portion. Along the winding axis, the first portion or the second portion has a lower height than the third portion.

[0028] On one hand, the aforementioned third part can be defined as the aforementioned electrode tab in a state of being bent along the radial direction of the aforementioned electrode assembly.

[0029] On the other hand, the second and third portions described above can be defined as electrode tabs in a state of bending along the radial direction of the electrode assembly.

[0030] Preferably, at least a portion of the third part can be divided into multiple segments that can be bent individually.

[0031] Preferably, each of the plurality of segments may have a geometric shape that connects more than one straight line, more than one curve, or a combination thereof.

[0032] In one example, the width of the lower part of each of the multiple slices can be greater than the width of the upper part.

[0033] In another example, the width of the bottom portion of each of the multiple slices can be the same as the width of the top portion.

[0034] In yet another example, the width of each of the multiple slices can decrease as it approaches the top from the bottom.

[0035] In yet another example, the width of each of the multiple slices can decrease first and then increase as it approaches the top from the bottom.

[0036] In yet another example, the width of each of the multiple slices can increase and then decrease as it approaches the top from the bottom.

[0037] In yet another example, the width of each of the multiple slices can first increase and then remain at a certain width as it approaches the top from the bottom.

[0038] In yet another example, the width of each of the multiple slices can decrease first and then maintain a certain width as it approaches the top from the bottom.

[0039] Preferably, the side of each of the plurality of segments can be composed of straight lines, curves, or a combination thereof.

[0040] In one example, the sides of each of the multiple slices may bulge outwards or inwards.

[0041] In another example, the upper corner of each of the multiple segments may have a chamfered shape.

[0042] Preferably, along a direction parallel to the winding direction, the lower inner angles of multiple segments can be increased individually or in groups.

[0043] On the one hand, along a direction parallel to the aforementioned winding direction, the lower interior angles of multiple segments can be increased individually or in groups within a range of 60 to 85 degrees.

[0044] On the other hand, each of the aforementioned plurality of segments may have a geometric shape in which the width decreases as it approaches the top, and the lower interior angle θ of the segment located in the winding loop with radius r centered on the core of the aforementioned electrode assembly belongs to the angle range of the following mathematical formula:

[0045]

[0046] (D is the width of the slice in the winding direction; r is the radius of the winding loop containing the slice; H is the height of the slice; p is the spacing between the slices).

[0047] On the other hand, the sides of each of the multiple slices are composed of straight lines, curves, or combinations thereof.

[0048] On the other hand, the sides of each of the multiple segments bulge outwards or inwards.

[0049] Each of the multiple segments has a chamfered corner at its upper part.

[0050] Preferably, a cutting groove can be sandwiched between multiple adjacent segments along the winding direction, the lower part of the cutting groove including: a bottom; and chamfered portions connecting the two ends of the bottom and the sides of the segments located on both sides of the cutting groove.

[0051] On the one hand, the radius of curvature of the chamfered portion can be greater than 0 and less than or equal to 0.1 mm, and more preferably, it can be from 0.01 mm to 0.05 mm.

[0052] On the other hand, the bottom can be flat.

[0053] On another aspect, the separation interval, defined by the distance between two points where the lines extending from the sides of the two segments located on both sides of the cut-off groove intersect and the lines extending from the bottom of the cut-off groove, can be from 0.05 mm to 1.00 mm.

[0054] In another aspect, the aforementioned plurality of segments may be made of aluminum foil, and the separation interval, defined by the distance between the two points where the lines extending from the sides of the two segments located on both sides of the aforementioned cutting groove intersect and the line extending from the bottom of the aforementioned cutting groove, is 0.5 mm to 1.00 mm.

[0055] On the other hand, the bottom of the aforementioned cut-off groove can be separated from the aforementioned active material layer by a certain distance.

[0056] Preferably, the separation distance between the bottom of the cut-off groove and the active material layer can be 0.2 mm to 4 mm.

[0057] Preferably, in the radial direction of the electrode assembly, the bending areas of the plurality of segments are located within a range of 0 mm to 1 mm above the lower end of the cut-off groove.

[0058] On the other hand, with the core center of the aforementioned electrode assembly as a reference, the circumferential angle of the arc formed by the lower end of each of the aforementioned multiple segments can be less than 45 degrees.

[0059] Preferably, when the radius of the winding loop including the slice, with the core center of the electrode assembly as the reference, is defined as r, and the width of the slice in the winding direction is defined as D(r), D(r) can satisfy the following mathematical formula.

[0060] 1≤D(r)≤(2*π*r / 360°)*45°.

[0061] On the other hand, as the radius r of the winding loop of the segment with the core center of the aforementioned electrode assembly as a reference increases, the width D(r) of the winding direction of each of the plurality of segments can gradually increase, increase in stages, or the opposite.

[0062] On another aspect, as the radius r of the winding loop containing the segment referenced to the core center of the aforementioned electrode assembly increases, the width D(r) of each of the plurality of segments in the winding direction can first gradually increase, or increase in stages and then gradually decrease, or decrease in stages, or vice versa. On another aspect, the circumferential angle of each of the plurality of segments can be substantially the same, referenced to the core center of the aforementioned electrode assembly.

[0063] On the other hand, along a direction parallel to the winding direction of the aforementioned electrode assembly, the widths of the winding direction of the plurality of segments may be substantially the same or increased at different ratios.

[0064] Preferably, as the radius r of the winding loop containing the segment with reference to the core center of the electrode assembly increases, the width of each of the plurality of segments can gradually increase or increase in stages within the range of 1 mm to 11 mm.

[0065] On another front, along a direction parallel to the aforementioned winding direction, the height of at least a portion of the third part in the winding axis direction may gradually or gradually change.

[0066] Preferably, along a direction parallel to the aforementioned winding direction, the height of at least a portion of the third part in the winding axis direction can gradually increase or increase in stages.

[0067] Preferably, along a direction parallel to the aforementioned winding direction, the height of at least a portion of the third part in the winding axis direction may first gradually increase or increase in stages and then gradually decrease or decrease in stages.

[0068] Preferably, the third portion and the selective second portion can be divided into multiple regions of different heights along a direction parallel to the winding direction, and the height of the uncoated portion in the multiple regions can be increased in stages along a direction parallel to the winding direction.

[0069] On one hand, the aforementioned first uncoated portion may include a section whose height varies in stages along a direction parallel to the aforementioned winding direction, from a first height h1 to a (N-1)th height h. N-1 (N is the height index, a natural number greater than 2) The variable height range and the uniform maintenance of the Nth height h N (greater than h) N-1 The height of the uniform range.

[0070] Preferably, N can be 2 to 30.

[0071] On the one hand, it has the aforementioned height h k The number of slices (k is a natural number from 1 to N) can be multiple, with a height h. k Multiple segments are configured on one or more winding loops.

[0072] On the other hand, in the case of including a height h k The starting radius of the winding loop of a slice (where k is a natural number from 1 to N) is defined as r. k At that time, more than 90% of the diameter of the core of the aforementioned electrode assembly will not be located in the aforementioned r k The bent part of the section is covered.

[0073] On the other hand, in including those with a height of h k The initial radius of the coil of the slice (k is a natural number from 1 to N) is r. k The core has a radius of r c At that time, the height h of the cut section k It can satisfy the following mathematical expression

[0074] 2mm≤h k ≤r k –α*r c (α is 0.90 to 1).

[0075] Preferably, taking the cross section along the winding axis as a reference, the electrode assembly in the radial direction sequentially includes a section without cut pieces, a height-variable section with variable cut piece height, and a height-uniform section with uniform cut piece height. The plurality of cut pieces are arranged in the height-variable section and the height-uniform section, and are bent along the radial direction of the electrode assembly to form a bent surface area.

[0076] On the one hand, the first part mentioned above may not be divided into multiple segments, and the omitted intervals of the aforementioned segments correspond to the first part mentioned above.

[0077] On the other hand, the aforementioned third part can be divided into multiple segments that can be bent individually, with the aforementioned variable height range and the aforementioned uniform height range corresponding to the aforementioned third part.

[0078] In another aspect, the second and third parts mentioned above can be divided into multiple segments that can be bent individually, with the variable height range and the uniform height range corresponding to the second and third parts mentioned above.

[0079] Preferably, within the aforementioned variable height range and the aforementioned uniform height range, the maximum height h of the sectional section is... max It can satisfy the following mathematical expression

[0080] h max ≤W foil –W scrap，min -W margin，min –W gap .

[0081] W foil It is the width of the current collector foil before the stencil is formed; W scrap，min It is the width equivalent to the minimum chip breaking allowance when cutting the current collector foil to form the slit; W margin，min It is the minimum serpentine margin of the separation membrane; W gap It is equivalent to the width of the insulating gap between the end of the second electrode, which is opposite to the first electrode and separated by the separation membrane, and the end of the separation membrane.

[0082] Preferably, when the first electrode is the anode, the insulating gap W gap It can be from 0.2mm to 6mm.

[0083] Preferably, when the first electrode is a cathode, the insulating gap W gap It can be from 0.1mm to 2mm.

[0084] Preferably, the minimum chip breaking allowance W is... scrap , min It can range from 1.5mm to 8mm. The minimum chip breaking allowance W depends on the cutting method used for the cut. scrap，min It can be 0.

[0085] Preferably, the minimum serpentine allowance W of the above-mentioned separation membrane margin，min It can be 0 to 1 mm.

[0086] Preferably, the height of the segment configured in the above-mentioned height variable range can be gradually increased or increased in stages within the range of 2mm to 10mm.

[0087] On one hand, in the radial direction of the aforementioned electrode assembly, the ratio of the radial length of the omitted section of the aforementioned slit to the radius of the aforementioned electrode assembly excluding the aforementioned core may be 10% to 40%.

[0088] On the other hand, in the radial direction of the aforementioned electrode assembly, the ratio of the radial length of the aforementioned height-variable range to the radial length corresponding to the aforementioned height-variable range and the aforementioned height-uniform range can be from 1% to 50%.

[0089] On another note, the ratio of the length of the electrode region corresponding to the aforementioned omitted section to the overall length of the first electrode can be from 1% to 30%.

[0090] On another note, the ratio of the length of the electrode region corresponding to the aforementioned height-variable range to the overall length of the aforementioned first electrode can be from 1% to 40%.

[0091] On another note, the ratio of the length of the electrode region corresponding to the aforementioned highly uniform interval to the overall length of the aforementioned first electrode can be 50% to 90%.

[0092] Preferably, the plurality of segments can be increased in stages or continuously along a direction parallel to the winding direction, at least one of the width in the winding direction and the height in the winding axis direction.

[0093] On one hand, along a direction parallel to the winding direction of the aforementioned electrode assembly, the aforementioned multiple segments can form multiple segments groups, and the width of the multiple segments in the winding direction and the height in the winding axis direction of the multiple segments belonging to the same segments group are substantially the same to each other.

[0094] Preferably, along a direction parallel to the winding direction of the electrode assembly, at least one of the width of the winding direction of multiple segments belonging to the same segment group and the height of the winding axis direction can be gradually increased or increased in stages.

[0095] On another aspect, along a direction parallel to the winding direction of the aforementioned electrode assembly, at least one of the width of the winding direction and the height of the winding axis direction of multiple segments belonging to the same segment group can be gradually increased or increased in stages and then gradually decreased or decreased in stages, or vice versa.

[0096] On one hand, when the width of the winding direction of each of three consecutive adjacent cutter groups in a direction parallel to the winding direction of the above-mentioned electrode assembly is set as W1, W2 and W3, a combination of cutter groups that are smaller than W2 / W1 may be included.

[0097] On the other hand, the first part mentioned above may not be divided into multiple segments, and the first part mentioned above will not be bent along the radial direction of the electrode assembly.

[0098] On the other hand, the second part may not be divided into multiple segments, and the second part will not be bent along the radial direction of the electrode assembly.

[0099] Preferably, an insulating coating may be formed at the boundary between the uncoated portion of the region existing at the bottom of the cut-off groove and the active material layer and the active material layer.

[0100] On one hand, the aforementioned insulating coating may include a polymer resin and inorganic fillers dispersed in the polymer resin.

[0101] On the other hand, the insulating coating is formed such that it can cover the boundary portion between the active material layer and the first uncoated portion along the winding direction.

[0102] On another aspect, the insulating coating is formed such that it can cover the boundary portion between the active material layer and the first uncoated portion with a width of 0.3 mm to 5 mm along the winding axis.

[0103] On the other hand, the end of the aforementioned insulating coating, based on the end of the aforementioned separating membrane, can be located in the range of -2mm to 2mm along the winding axis direction.

[0104] Preferably, the insulating coating may be exposed on the outside of the separation membrane.

[0105] Preferably, the lower end of the cut-off groove and the insulating coating can be separated by a distance of 0.5 mm to 2 mm.

[0106] Preferably, the end of the insulating coating in the winding axis direction can be located within the range of -2mm to 2mm with reference to the lower end of the cut-off groove.

[0107] Preferably, the second electrode may include a second active material portion coated with an active material layer along the winding direction, and the end of the second active material portion is located between the upper end and the lower end of the insulating coating in the winding axis direction.

[0108] In another aspect, the aforementioned third region can be divided into multiple segments that can be bent individually, and alternatively, the aforementioned second region can be divided into multiple segments that can be bent individually, and the aforementioned electrode assembly includes a bending surface region formed when the aforementioned multiple segments are bent along the radial direction of the aforementioned electrode assembly.

[0109] Preferably, with the core center of the electrode assembly as a reference, when the number of segments intersecting with a virtual line parallel to the winding axis at any radius position in the bending surface region is defined as the number of segments stacked at the corresponding radius position, the bending surface region may include a uniform stacking range where the number of segments stacked is uniform as it approaches the outer periphery (or the opposite direction) from the core side, and a stacking reduction range located outside the uniform stacking range where the number of segments stacked decreases as it approaches the outer periphery.

[0110] On the one hand, taking the core center of the aforementioned electrode assembly as a reference, the radial length of the aforementioned uniform stacking interval and the aforementioned decreasing stacking interval can correspond to the radial length of the radial interval in which the multiple windings containing the aforementioned multiple slices are located.

[0111] On the other hand, the electrode assembly may sequentially include, along the radial direction, a section with no cut-out, a section with variable height of cut-out, and a section with uniform height of cut-out. With the core center of the electrode assembly as a reference, the starting radius of the section with uniform stacking corresponds to the starting radius of the section with variable height.

[0112] Preferably, within the above-mentioned uniform layer number range, the layer number of the above-mentioned slice can be 10 to 35.

[0113] On one hand, the first electrode can be an anode, and in the above-mentioned uniform stacking range, the stacking thickness of the above-mentioned sectional piece is 100um to 875um.

[0114] On the other hand, the first electrode can be a cathode, and in the uniform stacking range, the stacking thickness of the sectional is 50 μm to 700 μm.

[0115] On the other hand, the ratio of the length of the aforementioned uniform stacking interval to the radial length of the aforementioned uniform stacking interval and the aforementioned decreasing stacking interval can be 30% to 85%.

[0116] Preferably, it may further include: a current collector welded to the bent surface region, wherein, in the radial direction of the electrode assembly, the welded area of ​​the current collector overlaps with the uniform stacking interval by at least 50%.

[0117] On the one hand, in the radial direction of the aforementioned electrode assembly, the area in the welding region of the aforementioned current collector that does not overlap with the aforementioned uniform stacking interval may overlap with the aforementioned reduced stacking interval.

[0118] On the other hand, the edge of the current collector can be welded to the bending surface region in such a way that it covers the end of the bent portion of the outermost segment in the radial direction of the electrode assembly.

[0119] Preferably, the welding strength of the welding area of ​​the current collector can be 2 kgf / cm². 2 above.

[0120] More preferably, the welding strength of the welding area of ​​the current collector can be 4 kgf / cm². 2 above.

[0121] In another aspect, according to the first claim, the aforementioned first uncoated portion may be composed of a metal foil, wherein the metal foil has an elongation of 1.5% to 3.0% and a tensile strength of 25 kgf / mm². 2 Up to 35 kgf / mm 2 .

[0122] Preferably, the metal foil can be aluminum foil.

[0123] Preferably, the camber length of the first electrode can be less than 20 mm.

[0124] Preferably, in the first active material portion, the ratio of the length of the short side parallel to the winding axis direction to the length of the long side parallel to the winding direction of the first active material portion is preferably 1.0% to 4.0%.

[0125] On the other hand, the height of the second part mentioned above decreases in stages or gradually as it moves from the core side of the electrode assembly toward the outer periphery.

[0126] In another aspect, the second and third portions are divided into multiple segments that can be bent individually, and the segments included in the second portion have at least one greater width in the winding direction and height in the winding axis direction than the segments included in the third portion.

[0127] In another aspect, the third part described above may include a cutout section without cutouts along the winding direction of the electrode assembly.

[0128] Preferably, the third part may include multiple cutout intervals along a direction parallel to the winding direction.

[0129] On the one hand, the width of each of the aforementioned multiple cutout intervals can be increased or decreased in a direction parallel to the aforementioned winding direction.

[0130] Preferably, the height of the uncoated portion of the omitted section of the above-mentioned cut can be substantially the same as the height of the uncoated portion of the first part or the uncoated portion of the second part.

[0131] Preferably, the plurality of segments can be located within a circumferential angle range predetermined with reference to the core center of the electrode assembly.

[0132] On one hand, the aforementioned multiple segments can be located in two or more fan-shaped or polygonal regions arranged circumferentially with reference to the core center of the aforementioned electrode assembly.

[0133] Preferably, the circumferential angle of the aforementioned sector region can be 20 degrees or more.

[0134] In another aspect, the second electrode may include a second active material portion coated with an active material layer and a second uncoated portion without an active material layer along the winding direction. At least a portion of the second uncoated portion is defined as an electrode tab in itself. The second uncoated portion includes a section divided into a plurality of segments that can be bent individually. The plurality of segments are bent along the radial direction of the electrode assembly to form a bent surface region.

[0135] According to another aspect of the present invention for addressing the aforementioned technical problem, an electrode assembly comprising a first electrode, a second electrode, and a separation membrane sandwiched therebetween are wound around a winding shaft to define a core and an outer peripheral surface. In the electrode assembly, the first electrode may include, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. The first uncoated portion includes, from the core side of the electrode assembly along the outer peripheral side, a section divided into multiple segments capable of being individually bent. The multiple segments are bent along the radial direction of the electrode assembly to form a bending surface region. The bending surface region includes, along the radial direction, a uniform layer number interval where the number of layers of the segments is 10 or more, and a layer number decreasing interval adjacent to the uniform layer number interval where the number of layers of the segments decreases as they move away from the uniform layer number interval.

[0136] According to another aspect of the present invention for achieving the above-mentioned technical problems, an electrode assembly comprising an anode, a cathode, and a separation membrane sandwiched between them, defined by winding around a winding shaft to define a core and an outer peripheral surface, wherein the anode may include, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer, at least a portion of the first uncoated portion being used as an electrode tab, the first uncoated portion comprising, from the core side of the electrode assembly toward the outer peripheral side, a plurality of individually bendable segments, the plurality of segments being stacked in multiple layers when bent along the radial direction of the electrode assembly to form a bending surface region, the bending surface region including, along the radial direction, a uniform stacking interval of the segments and a stack decreasing interval adjacent to the uniform stacking interval, wherein the stacking thickness of the segments in the uniform stacking interval is 100 μm to 875 μm.

[0137] Preferably, the electrode assembly may further include a current collector welded to the uniformly stacked layer range, such that the uniformly stacked layer range overlaps with at least a portion of the welding region. In the welding region, the layer thickness of the slab may be from 100 μm to 875 μm.

[0138] According to another aspect of the present invention for achieving the above-mentioned technical problems, an electrode assembly comprising an anode, a cathode, and a separation membrane sandwiched between them, defined by winding around a winding shaft to define a core and an outer peripheral surface, wherein the cathode may include, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer, at least a portion of the first uncoated portion being used as an electrode tab, the first uncoated portion comprising, from the core side of the electrode assembly along the outer peripheral side, a plurality of individually bendable segments, the plurality of segments being stacked in multiple layers when bent along the radial direction of the electrode assembly to form a bending surface region, the bending surface region including, along the radial direction, a uniform stacking interval of the segments and a decreasing stacking interval adjacent to the uniform stacking interval, wherein the stacking thickness of the segments in the uniform stacking interval is 50 μm to 700 μm.

[0139] Preferably, the electrode assembly may further include a current collector welded to the uniformly stacked layer range, such that the uniformly stacked layer range overlaps with at least a portion of the welding area. In the welding area, the layer thickness of the sectional section may be from 50 μm to 700 μm.

[0140] According to an aspect of the present invention for addressing the aforementioned technical problems, a battery may include: an electrode assembly having a first electrode, a second electrode, and a separating membrane sandwiched therebetween wound around a winding axis to define a core and an outer peripheral surface; the first electrode may include, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer; at least a portion of the first uncoated portion being defined as an electrode tab; the first uncoated portion including a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer peripheral surface of the electrode assembly, and a third portion between the first and second portions; in the winding axis direction, the first portion or the second portion having a smaller height than the third portion; a battery casing including an open end and an opposite bottom portion, the electrode assembly being housed in the space between the open end and the bottom portion, electrically connected to one of the first and second electrodes, thereby having a first polarity; a seal for sealing the open end of the battery casing; and a terminal electrically connected to the other of the first and second electrodes, with its surface exposed externally, and having a second polarity.

[0141] On one hand, the height of the second part in the winding axis direction can be smaller than that of the third part. The battery casing has an inwardly pressed-in rolled edge in the area adjacent to the open end. The inner surface of the rolled edge, which is opposite to the upper edge of the electrode assembly, is separated from the second part by a predetermined interval.

[0142] Preferably, the pressing depth D1 of the rolled edge and the distance D2 from the inner surface of the battery casing to the boundary point between the second part and the third part can satisfy the relationship D1≤D2.

[0143] On the other hand, the battery may also include: a current collector electrically connected to the third portion; and an insulator covering the current collector and fixed in such a way that its edge is sandwiched between the inner surface of the rolled edge and the current collector.

[0144] Preferably, the diameter of the current collector can be smaller than the minimum inner diameter of the inner surface of the rolled edge portion, and the diameter of the current collector is the same as or larger than the outermost diameter of the third portion.

[0145] On the other hand, the current collector can be located at a higher position than the rolled edge in the winding axis direction.

[0146] In another aspect, the aforementioned sealing element may include: a cover that seals the open end of the battery casing; a pad that is sandwiched between the edge of the cover and the open end of the battery casing; and a crimping portion that extends toward the inside of the battery casing and bends, and together with the pad surrounds the edge of the cover for fixation, wherein the terminal having the second polarity is the cover.

[0147] In another aspect, the battery also includes a first current collector electrically connected to the first uncoated portion, wherein the terminal is provided in an insulated manner in a through hole formed on the bottom surface of the battery casing, and is a rivet terminal electrically connected to the first current collector and having the second polarity.

[0148] In another aspect, the battery may further include an insulator sandwiched between the inner side of the bottom surface of the battery casing and the upper surface of the first current collector, so as to achieve electrical insulation between the inner side of the bottom surface of the battery casing and the first current collector.

[0149] Preferably, the insulator may have a thickness corresponding to the distance between the inner side of the bottom surface of the battery casing and the upper surface of the first current collector, and be in close contact with the inner side of the bottom surface of the battery casing and the upper surface of the first current collector.

[0150] In another aspect, the aforementioned rivet terminal may include a flat portion at its lower end, and the aforementioned insulator includes an opening for exposing the flat portion, through which the flat portion is welded to the aforementioned first current collector.

[0151] In another aspect, the second electrode may include, along the winding direction, a second active material portion coated with an active material layer and a second uncoated portion without an active material layer. The second electrode has the first polarity, and at least a portion of the second uncoated portion is defined as an electrode tab. Furthermore, the battery may also include a second current collector electrically connected to the second uncoated portion, with at least a portion of the edge of the second current collector bonded to the sidewall of the battery casing.

[0152] In another aspect, the second electrode may include, along the winding direction, a second active material portion coated with an active material layer and a second uncoated portion without an active material layer. The second electrode has the aforementioned first polarity, and at least a portion of the second uncoated portion is defined as an electrode tab. Furthermore, the battery may further include a second current collector electrically connected to the second uncoated portion, with at least a portion of the edge of the second current collector bonded to the sidewall of the battery casing. Preferably, the outer diameter of the first current collector may be the same as or larger than that of the second current collector.

[0153] Preferably, the first current collector and the second current collector can be welded to the first uncoated portion and the second uncoated portion along the radial direction of the electrode assembly to form a welding pattern, wherein the length of the welding pattern of the first current collector is longer than the length of the welding pattern of the second current collector.

[0154] Preferably, the welding patterns of the first current collector and the second current collector can be located at substantially the same distance from the core center of the electrode assembly.

[0155] Preferably, the battery casing may include an inwardly pressed-in rolled edge on the inner wall adjacent to the open end, and the edge of the second current collector is electrically connected to the rolled edge.

[0156] Preferably, the area where the second current collector makes electrical contact with the second uncoated portion can be located inside the inner surface of the rolled edge portion.

[0157] In another aspect, the battery may include: a cover whose edge is supported by the rolled edge and is non-polar; a pad sandwiched between the edge of the cover and the open end of the battery casing; and a crimping portion that extends toward the inside of the open end of the battery casing and bends, together with the pad, surrounding the edge of the cover for fixation. Preferably, the edge of the second current collector can be fixed by the crimping portion sandwiched between the rolled edge and the pad.

[0158] Preferably, the edge of the second current collector can be welded to the rolled edge portion.

[0159] According to another aspect of the present invention for achieving the above-mentioned technical problems, a battery may include: an electrode assembly, wherein a first electrode, a second electrode, and a separator sandwiched therebetween are wound around a winding axis to define a core and an outer peripheral surface; the first electrode includes, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer; the first uncoated portion includes, from the core side of the electrode assembly along the outer peripheral side, a section divided into a plurality of individually bendable segments; the plurality of segments are bent along the radial direction of the electrode assembly to form a bending surface region; the bending surface region includes, along the radial direction, a... The aforementioned segments have a stacking number of 10 or more in a uniform stacking number range and a stacking number decreasing range adjacent to the aforementioned uniform stacking number range where the stacking number of the aforementioned segments decreases as they move away from the aforementioned uniform stacking number range; a battery casing, including an open end and an opposite bottom portion, housing the aforementioned electrode assembly in the space between the open end and the bottom portion, electrically connected to one of the aforementioned first electrode and the aforementioned second electrode to have a first polarity; a sealing member for sealing the open end of the aforementioned battery casing; and a terminal, electrically connected to the other of the aforementioned first electrode and the aforementioned second electrode, with its surface exposed to the outside and having a second polarity.

[0160] According to another aspect of the present invention for achieving the above-mentioned technical problem, a battery may include: an electrode assembly having an anode, a cathode, and a separator sandwiched therebetween wound around a winding shaft to define a core and an outer peripheral surface; the anode comprising, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer; at least a portion of the first uncoated portion being used as an electrode tab; the first uncoated portion comprising, from the core side of the electrode assembly along the outer peripheral side, a plurality of individually bendable segments; the plurality of segments being stacked in multiple layers when bent along the radial direction of the electrode assembly to form a bending surface region; the bending surface region comprising, along the radial direction, the aforementioned... The battery casing comprises: a uniformly stacked interval of slices and a decreasing interval of slices located adjacent to the uniformly stacked interval, wherein the number of slices decreases as they move away from the uniformly stacked interval; the stacking thickness of the slices in the uniformly stacked interval is 100 μm to 875 μm; a battery casing including an open end and an opposite bottom portion, wherein the electrode assembly is housed in the space between the open end and the bottom portion, and is electrically connected to one of the anode and the cathode and has a first polarity; a seal that seals the open end of the battery casing; and a terminal that is electrically connected to the other of the anode and the cathode, has its surface exposed to the outside, and has a second polarity.

[0161] Preferably, the battery according to the present invention may further include: a current collector welded to the aforementioned uniform layer number range, such that the uniform layer number range overlaps with the welding area. In the aforementioned welding area, the layer thickness of the sectional sheet may be from 100 μm to 875 μm.

[0162] According to another aspect of the present invention for achieving the above-mentioned technical problems, a battery may include: an electrode assembly having an anode, a cathode, and a separator sandwiched therebetween wound around a winding shaft to define a core and an outer peripheral surface; the cathode comprising, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer; at least a portion of the first uncoated portion being used as an electrode tab; the first uncoated portion comprising, from the core side of the electrode assembly along the outer peripheral side, a plurality of individually bendable segments; the plurality of segments being stacked in multiple layers when bent along the radial direction of the electrode assembly to form a bending surface region; the bending surface region comprising, along the radial direction, an upper... The battery casing includes an evenly stacked interval of the slices and an interval adjacent to the evenly stacked interval where the number of layers of the slices decreases as they move away from the evenly stacked interval. The layer thickness of the slices in the evenly stacked interval is 50 μm to 700 μm. The battery casing includes an open end and a bottom part opposite thereto, and the electrode assembly is housed in the space between the open end and the bottom part. The electrode assembly is electrically connected to one of the anode and the cathode and has a first polarity. The battery casing is sealed to the open end of the battery casing. The battery casing is electrically connected to the other of the anode and the cathode, with its surface exposed to the outside and having a second polarity.

[0163] Preferably, the battery according to the present invention may further include: a current collector welded to the aforementioned uniform layer number range, such that the uniform layer number range and the welding area overlap. In the welding area, the layer thickness of the sectional sheet may be from 50 μm to 700 μm.

[0164] The technical problem according to the present invention can be solved by a battery pack comprising a plurality of the above-described batteries.

[0165] Preferably, the ratio of the diameter to the height of the battery can be greater than 0.4.

[0166] Preferably, the shape factor of the battery can be 46110, 4875, 48110, 4880 or 4680.

[0167] Preferably, the resistance of the battery can be below 4mΩ, or above 0.5mΩ and below 4mΩ, and more preferably above 1mΩ and below 4mΩ.

[0168] According to one aspect, in the aforementioned battery pack, multiple batteries can be arranged in a predetermined number of columns, with the electrode terminals of each battery and the outer surface of the bottom of the battery casing facing upwards.

[0169] According to another aspect, the aforementioned battery pack may include multiple buses that connect multiple batteries in series and in parallel.

[0170] Preferably, the plurality of buses can be configured on the upper part of the plurality of batteries, each bus including: a main body extending between the plurality of electrode terminals of the plurality of adjacent batteries; a plurality of first bus terminals extending toward one side of the main body, thereby electrically engaging with the electrode terminals of the battery located in the aforementioned one side direction; and a plurality of second bus terminals extending toward the other side of the main body, thereby electrically engaging with the outer surface of the bottom surface of the battery casing of the battery located in the aforementioned other side direction.

[0171] The technical problem according to the present invention can also be solved by a vehicle including the above-described battery pack.

[0172] [Invention Effects]

[0173] According to one aspect of the invention, by using the uncoated portions protruding from the upper and lower parts of the electrode assembly as electrode tabs themselves, it is possible to reduce the internal resistance of the battery and increase the energy density.

[0174] According to another aspect of the invention, the uncoated portion structure of the electrode assembly is improved, thereby avoiding interference between the inner surface of the electrode assembly and the battery casing during the formation of the rolled edge portion of the battery casing, thereby preventing short circuits inside the cylindrical battery caused by local deformation of the electrode assembly.

[0175] According to another aspect of the present invention, the structure of the uncoated portion of the electrode assembly is improved, thereby preventing the uncoated portion from tearing when bent, and the number of layers of the uncoated portion is sufficiently increased, thereby improving the welding strength of the current collector.

[0176] According to another aspect of the invention, a slit structure is applied to the uncoated portion of the electrode, and the dimensions (width, height, and spacing) of the slit are optimized, thereby significantly increasing the number of slit stacks in the area used as the welding target area, thereby improving the physical properties of the area used for welding current collectors.

[0177] According to another aspect of the invention, by applying a structure in which the current collector is welded over a large area in the bent surface region formed by bending multiple segments, it is possible to provide an electrode assembly that increases energy density and reduces resistance.

[0178] According to another aspect of the invention, it is possible to provide a cylindrical battery whose design is improved to enable electrical wiring to be performed from the top.

[0179] According to another aspect of the invention, the structure of the uncoated portion adjacent to the core of the electrode assembly is improved, preventing the uncoated portion from blocking the cavity in the core of the electrode assembly when bent, and enabling simple electrolyte injection and welding of the battery casing (or terminals) to the current collector.

[0180] According to another aspect of the present invention, it is possible to provide a cylindrical battery having a structure with low internal resistance, preventing internal short circuits, and improving the welding strength of the current collector and the uncoated portion, a battery pack including the cylindrical battery, and an automobile.

[0181] In particular, the present invention can provide a cylindrical battery with a diameter-to-height ratio of 0.4 or higher and a resistance of 4 mΩ or lower, as well as a battery pack including the cylindrical battery and an automobile.

[0182] In addition, the present invention can achieve various other effects, which are described in the various embodiments, or the corresponding descriptions are omitted for effects that can be easily deduced by those skilled in the art. Attached Figure Description

[0183] Preferred embodiments of the invention are illustrated in the accompanying drawings, which serve to further explain the technical concept of the invention together with the detailed description of the invention that follows. Therefore, the invention should not be construed as being limited to the scope shown in these drawings.

[0184] Figure 1 This is a top view showing the electrode structure used in the manufacture of existing tabless cylindrical batteries.

[0185] Figure 2 This diagram illustrates the electrode winding process of a conventional tabless cylindrical battery.

[0186] Figure 3 The process of welding a current collector in the bent surface area of ​​the uncoated portion of a conventional tabless cylindrical battery is shown.

[0187] Figure 4 This is a top view showing the electrode structure according to the first embodiment of the present invention.

[0188] Figure 5 This is a top view showing the electrode structure according to a second embodiment of the present invention.

[0189] Figure 6 This is a top view showing the electrode structure according to a third embodiment of the present invention.

[0190] Figure 7a This is a top view showing the electrode structure according to the fourth embodiment of the present invention.

[0191] Figure 7bThis is a diagram illustrating the definition of the width, height, and separation interval of a slice according to an embodiment of the present invention.

[0192] Figure 7c The diagram shows the arc formed by the lower end of the strip used to define the width of the strip when the electrode is wound according to an embodiment of the present invention, with the core center of the electrode assembly as the reference.

[0193] Figure 7d The diagram schematically illustrates the height h1, h2, h3, h4, and core radius r of the truncated section according to an embodiment of the present invention. c And a diagram showing the relationship between the radii r1, r2, r3, and r4 of the winding loops where the cut pieces begin to appear.

[0194] Figure 7e This is a conceptual diagram used to determine the maximum value (hmax) of the height H of a cut within the variable height range of the cut.

[0195] Figure 7f It is a schematic diagram used to illustrate the mathematical formula for determining the lower interior angle θ of a section.

[0196] Figure 7g This is a top view showing a modified structure of the electrode according to a fourth embodiment of the present invention.

[0197] Figure 7h This is a top view showing a single region where multiple segments can be positioned when the electrode according to a modified embodiment of the present invention is wound into an electrode assembly.

[0198] Figure 8a A top view of the electrode structure according to a fifth embodiment of the present invention is shown.

[0199] Figure 8b This is a diagram illustrating the definition of the width, height, and separation interval of a slice according to another embodiment of the present invention.

[0200] Figure 8c This is a top view showing a modified structure of the electrode according to a fifth embodiment of the present invention.

[0201] Figure 9 This is a diagram illustrating the sectional structure of various modifications according to the present invention.

[0202] Figure 10a This is a schematic diagram showing a cross-section of the bent surface region formed when the cut piece is bent toward the core side of the electrode assembly.

[0203] Figure 10b This is a simplified top perspective view of an electrode assembly with a bent surface region.

[0204] Figure 10cThis is a graph showing the results of counting the number of layers of the truncated section in the radial direction in the bent surface region of the anode formed on the upper part of multiple electrode assemblies, according to Examples 1-1 to 1-7 and the comparative example.

[0205] Figure 10d This is a graph showing the results of counting the number of stacked segments measured in the radial direction in the bent surface region of the anode formed on the upper part of multiple electrode assemblies for Examples 2-1 to 2-5, Examples 3-1 to 3-4, Examples 4-1 to 4-3, and Examples 5-1 to 5-2.

[0206] Figure 10e This is a graph showing the results of counting the number of layers of the segments measured in the radial direction in the bent surface region of the anode formed on the upper part of the electrode assembly for Examples 6-1 to 6-6 and Examples 7-1 to 7-6.

[0207] Figure 10f This is a top view of an electrode assembly showing a uniform stacking interval b1 and a decreasing stacking interval b2 in the bent surface region of a section according to an embodiment of the present invention.

[0208] Figure 11 This is a cross-sectional view of a gel roll-type electrode assembly that uses the electrodes of the first embodiment as the first electrode (anode) and the second electrode (cathode) along the Y-axis direction (winding axis direction).

[0209] Figure 12 This is a cross-sectional view of a gel roll-type electrode assembly that uses the electrodes of the second embodiment as the first electrode (anode) and the second electrode (cathode) along the Y-axis direction (winding axis direction).

[0210] Figure 13 It is a cross-sectional view of a gel roll-type electrode assembly that has been cut along the Y-axis direction (wrap-up axis direction) and uses any one of the electrodes of the third to fifth embodiments (variant examples thereof) as the first electrode (anode) and the second electrode (cathode).

[0211] Figure 14 This is a cross-sectional view of the electrode assembly according to another embodiment of the present invention, cut along the Y-axis direction (winding axis direction).

[0212] Figure 15 This is a cross-sectional view of the electrode assembly according to another embodiment of the present invention, cut along the Y-axis direction (winding axis direction).

[0213] Figure 16 This is a cross-sectional view of the electrode assembly according to another embodiment of the present invention, cut along the Y-axis direction (winding axis direction).

[0214] Figure 17 This is a cross-sectional view of a cylindrical battery according to an embodiment of the present invention, cut along the Y-axis.

[0215] Figure 18 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0216] Figure 19 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0217] Figure 20 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0218] Figure 21 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0219] Figure 22 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0220] Figure 23 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0221] Figure 24 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0222] Figure 25 This is a cross-sectional view of a cylindrical battery according to another embodiment of the present invention, cut along the Y-axis.

[0223] Figure 26 This is a top view showing the structure of a first current collector according to an embodiment of the present invention.

[0224] Figure 27 This is a top top view showing the structure of a second current collector according to an embodiment of the present invention.

[0225] Figure 28 This is a top view showing the electrical connection of multiple cylindrical batteries.

[0226] Figure 29 yes Figure 28 A magnified view of a portion of the image.

[0227] Figure 30 This is a diagram that briefly illustrates the configuration of a battery pack according to an embodiment of the present invention.

[0228] Figure 31 This is a simplified illustration of a car including a battery pack according to an embodiment of the present invention. Detailed Implementation

[0229] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Before proceeding, the terms and words used in this specification and claims should not be limited to their ordinary or dictionary meanings. Given the principle that inventors may appropriately define terms and concepts in order to best illustrate their invention, they should be interpreted as meanings and concepts consistent with the technical concept of the present invention.

[0230] Therefore, the embodiments described in this specification and the configuration shown in the accompanying drawings are only one of the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. It should be understood that at the time of filing this application, there may be various equivalents and multiple modifications that can replace these.

[0231] Furthermore, to aid in understanding the invention, the dimensions of some constituent elements in the drawings are sometimes exaggerated and not shown in actual scale. Also, in different embodiments, the same reference numerals may be used to label the same constituent elements.

[0232] The phrase "identical" to two comparison objects means "substantially identical." Therefore, substantially identical can include cases with deviations considered low within the art, such as within 5%. Furthermore, uniformity of a parameter within a region can mean uniformity from an average perspective within the corresponding region.

[0233] First, an electrode assembly according to an embodiment of the present invention will be described. The electrode assembly may be a gel roll type electrode assembly having a first electrode in a sheet shape, a second electrode, and a separation membrane sandwiched between them, wound in one direction. However, the present invention is not limited to any particular type of electrode assembly.

[0234] Preferably, at least one of the first electrode and the second electrode includes an uncoated portion at the long side end in the winding direction that is not coated with active material. At least a portion of the uncoated portion is used as an electrode tab in itself. The uncoated portion includes a core-side uncoated portion adjacent to the core of the electrode assembly, an outer peripheral-side uncoated portion adjacent to the outer peripheral surface of the electrode assembly, and an intermediate uncoated portion sandwiched between the core-side uncoated portion and the outer peripheral-side uncoated portion.

[0235] Preferably, the height of at least one of the uncoated portion on the core side and the uncoated portion on the outer periphery side is relatively lower than that of the uncoated portion in the middle.

[0236] Figure 4 This is a top view showing the structure of the electrode 40 according to the first embodiment of the present invention.

[0237] Reference Figure 4The electrode 40 of the first embodiment includes a current collector 41 made of metal foil and an active material layer 42. The metal foil can be a conductive metal, such as aluminum or copper, and is appropriately selected according to the polarity of the electrode 40. The active material layer 42 is formed on at least one side of the current collector 41. The active material layer 42 is formed along the winding direction X. The electrode 40 includes an uncoated portion 43 at its long side end in the winding direction X. The uncoated portion 43 is a region of the current collector 41 that is not coated with active material. The region of the current collector 41 on which the active material layer 42 is formed can be named the active material portion.

[0238] In electrode 40, the width of the active material portion in the short side direction of current collector 41 can be 50 mm to 120 mm, and the length of the active material portion in the long side direction of current collector 41 can be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion can be 1.0% to 4.0%.

[0239] Preferably, in electrode 40, the width of the active material portion in the short side direction of current collector 41 can be 60 mm to 70 mm, and the length of the active material portion in the long side direction of current collector 41 can be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion can be 1.2% to 2.3%.

[0240] The ratio of the short side to the long side of the active material portion is significantly lower than that of the electrodes used in cylindrical batteries with shape factors of 1865 or 2170, where the ratio is 6% to 11%.

[0241] Preferably, the elongation of the current collector 41 is 1.5% to 3.0%, and the tensile strength can be 25 gf / mm². 2 Up to 35 kgf / mm 2 Elongation and tensile strength can be measured according to the IPC-TM-650 measurement method. Electrode 40 is manufactured by pressing after the active material layer 42 is formed on the current collector 41. During pressing, the elongation of the uncoated area 43 and the active material layer 42 area differs. Therefore, wrinkling occurs on the pressed electrode 40, and the longer the electrode 40, the more severe the wrinkling.

[0242] When optimizing the elongation and tensile strength of the current collector 41, the bending length after crimping is reduced to less than 20 mm when the length of the electrode 40 is approximately 4 m. The bending length is the maximum bending amount of the electrode 20 in the winding direction X when the wrinkled electrode 20 is unwound. The maximum bending amount can be measured at the outer peripheral end. With optimized elongation and tensile strength of the current collector 41 and a small bending length of the electrode 40, serpentine defects do not occur during the denting operation of the uncoated portion 43 or the winding process of the electrode 40.

[0243] The lower the elongation, the more prone the current collector 41 is to break. When the elongation of the current collector 41 is less than 1.5%, the rolling process of the current collector 41 deteriorates, and thus, when the current collector 41 is pressed against the electrode 40 coated with the active material layer 42, wire breakage may occur. Conversely, when the elongation of the current collector 41 exceeds 3.0%, the elongation of the active material portion of the electrode 40 increases significantly, and the bending length increases substantially. If the tensile strength of the current collector 41 is less than 25 kgf / mm², further damage may occur. 2 Or exceeding 35 kgf / mm 2 If this happens, the electrode processability of electrode 40 will decrease.

[0244] Bending is particularly problematic in anode current collectors made of aluminum foil. If the elongation is 1.5% to 3.0% and the tensile strength is 25 kgf / mm² according to the present invention... 2 Up to 35 kgf / mm 2 Using aluminum foil as a current collector can suppress bending. Ideally, an active material layer should be formed on such a current collector before using it as an anode.

[0245] Preferably, an insulating coating 44 may be formed at the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating 44 is formed such that at least a portion overlaps with the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating 44 prevents short circuits between two electrodes of opposite polarities sandwiching the separation membrane. The insulating coating 44 may cover the boundary portion between the active material layer 42 and the uncoated portion 43 with a width of 0.3 mm to 5 mm. The width of the insulating coating 44 may vary along the winding direction of the electrode 40. The insulating coating 44 comprises a polymer resin and may include inorganic fillers such as Al2O3. The portion of the current collector 41 covered by the insulating coating 44 is not an area coated with the active material layer and can therefore be considered an uncoated portion.

[0246] The uncoated portion 43 includes a core-side uncoated portion B1 adjacent to the core side of the electrode assembly, an outer peripheral-side uncoated portion B3 adjacent to the outer peripheral side of the electrode assembly, and an intermediate uncoated portion B2 sandwiched between the core-side uncoated portion B1 and the outer peripheral-side uncoated portion B3.

[0247] When the electrode 40 is wound into a gel roll type electrode assembly, the uncoated portion B1 on the core side, the uncoated portion B3 on the outer periphery side, and the uncoated portion B3 in the middle can be defined as the uncoated portion of the region adjacent to the core side, the uncoated portion of the region adjacent to the outer periphery side, and the uncoated portion of the remaining region, respectively.

[0248] Hereinafter, the uncoated portion B1 on the core side, the uncoated portion B3 on the outer periphery side, and the uncoated portion B2 in the middle will be named the first part, the second part, and the third part, respectively.

[0249] In one example, the first part B1 may be an uncoated portion of the electrode region including the innermost winding, and the second part may be an uncoated portion of the electrode region including the outermost winding.

[0250] In another example, the boundary of B1 / B2 can be appropriately defined as the point where the height (or variation pattern) of the uncoated portion on the outer periphery substantially changes from the core side of the electrode assembly to the outer periphery, or as a point representing a specified percentage of the radius of the electrode assembly (e.g., 5%, 10%, 15% of the radius, etc.).

[0251] The boundary of B2 / B3 can be defined as the point where the height (or variation pattern) of the uncoated portion (from the outer periphery of the electrode assembly) substantially changes towards the core side, or as a specified percentage based on the radius of the electrode assembly (e.g., 85%, 90%, 95% of the radius, etc.). If the boundaries of B1 / B2 and B2 / B3 are specified, the third part B2 can be automatically specified.

[0252] If only the boundaries of B1 / B2 are specified, the boundaries of B2 / B3 can be appropriately selected near the outer periphery of the electrode assembly. In one example, the second portion can be defined as the uncoated portion of the electrode region constituting the outermost winding. Conversely, if only the boundaries of B2 / B3 are specified, the boundaries of B1 / B2 can be appropriately selected near the core side of the electrode assembly. In one example, the first portion can be defined as the uncoated portion of the electrode region constituting the innermost winding.

[0253] In the first embodiment, the heights of the uncoated portions 43 are not uniform, exhibiting relative differences in the winding direction X. Specifically, the height (length in the Y-axis direction) of the second portion B3 is greater than 0 and relatively smaller than that of the first portion B1 and the third portion B2.

[0254] Figure 5 This is a top view showing the structure of the electrode 45 according to a second embodiment of the present invention.

[0255] Reference Figure 5 The only difference between the electrode 45 of the second embodiment and that of the first embodiment is that the height of the second part B3 gradually decreases as it approaches the outer periphery, while the rest of the configuration is substantially the same.

[0256] In one variation, the second part B3 can be modified into a stepped shape with progressively decreasing height (see dashed line).

[0257] Figure 6 This is a top view showing the structure of the electrode 50 according to a third embodiment of the present invention.

[0258] Reference Figure 6In the third embodiment, the height of the first portion B1 and the second portion B3 of the electrode 50 is above 0 and relatively lower than that of the third portion B2. Furthermore, the heights of the first portion B1 and the second portion B3 may be the same or different from each other.

[0259] Preferably, the height of the third part B2 can have a stepped shape that increases in stages as it approaches the outer periphery from the core side.

[0260] Patterns 1 to 7 divide the third section B2 around the position where the height of the uncoated portion 43 changes. Preferably, the number of multiple patterns and the height (length in the Y-axis direction) and width (length in the X-axis direction) of each pattern can be adjusted to maximize stress dispersion during the bending process of the uncoated portion 43. Stress dispersion is to prevent tearing of the uncoated portion 43 when it bends towards the core side of the electrode assembly.

[0261] The width d of part B1 B1 The design is based on the premise that bending the multiple patterns of the third part B2 towards the core side will not obstruct the core of the electrode assembly. The core refers to the cavity existing in the winding center of the electrode assembly.

[0262] In one example, the width d of the first part B1 B1 It can be increased proportionally to the bending length of Pattern 1. The bending length is equivalent to the height of the pattern relative to the bending point of the pattern.

[0263] Preferably, the width d of the first part B1 B1 The radius width of the multiple coils formed by the first part B1 can be set to exceed the bending length of pattern 1. In a modified example, the width d of the first part B1 is... B1 It can be set such that the value of the radial width of the multiple coils formed by subtracting the bending length of pattern 1 from the first part B1 is less than 0 or reaches less than 10% of the core radius.

[0264] In a specific example, where electrode 60 is used to manufacture an electrode assembly for a cylindrical battery with a form factor of 4680, the width d of the first portion B1 is determined based on the diameter of the core of the electrode assembly and the bending length of pattern 1. B1 It can be set from 180mm to 350mm.

[0265] In one embodiment, the width of each pattern can be designed to form one or more winding loops constituting the electrode assembly.

[0266] In one variation, the height of the third part B2 may have a stepped shape that first increases and then decreases as it approaches the outer periphery from the core side.

[0267] In another variation, the second part B3 can be modified to have the same structure as the second embodiment.

[0268] In yet another variation, the pattern structure applied to the third part B2 can be extended to the second part B3 (refer to the dashed line).

[0269] Figure 7a This is a top view showing the structure of the electrode 60 according to a fourth embodiment of the present invention.

[0270] Reference Figure 7a In the fourth embodiment, the height of the first portion B1 and the second portion B3 of the electrode 60 in the Y direction along the winding axis is 0 or higher, and is relatively smaller than that of the third portion B2. Furthermore, the heights of the first portion B1 and the second portion B3 in the Y direction along the winding axis can be the same or different.

[0271] Preferably, at least a portion of the third part B2 may include a plurality of segments 61. The height of the plurality of segments 61 may increase in stages from the core side to the outer periphery. The plurality of segments 61 have a geometric shape in which their width decreases from the bottom to the top. Preferably, the geometric shape is trapezoidal. The shape of the geometric shape can be varied, as will be described in detail later.

[0272] The cut piece 61 can be formed using laser grooving. The cut piece 61 can also be formed using known foil cutting processes such as ultrasonic cutting or trimming.

[0273] In the fourth embodiment, in order to prevent damage to the active material layer 42 and / or the insulating coating 44 when bending the uncoated portion 43, preferably, at the lower end of the cut groove between the slits 61 ( Figure 7bA predetermined gap is formed between the G) and the active material layer 42. This is because stress concentrates near the lower end of the cut-off groove 63 when the uncoated portion 43 is bent. The gap can vary depending on the winding direction of the electrode 60. The gap is 0.2 mm to 4 mm, preferably 1.5 mm to 2.5 mm. If the gap is adjusted within the corresponding value range, the gap can prevent the active material layer 42 and / or the insulating coating 44 near the lower end of the cut-off groove 63 from being damaged by the stress generated when bending the uncoated portion 43. Furthermore, the gap can prevent the active material layer 42 and / or the insulating coating 44 from being damaged due to tolerances when scoring or cutting the cut piece 61. The lower end of the cut-off groove 63 and the insulating coating 44 can be separated by 0.5 mm to 2.0 mm. When the electrode 60 is wound, the end of the insulating coating 44 in the winding axis Y direction can be located in the range of -2 mm to 2 mm along the winding axis direction based on the end of the separation membrane. The insulating coating 44 prevents short circuits between two electrodes of opposite polarities separated by the separation membrane and supports the bending point when the sheet 61 is bent. To improve the effectiveness of preventing short circuits between the two electrodes, the insulating coating 44 can be exposed to the outside of the separation membrane. Furthermore, to further maximize the effectiveness of preventing short circuits between the two electrodes, the width of the insulating coating 44 can be increased so that the end of the insulating coating 44 in the Y direction of the winding axis is located above the lower end of the cut-off groove 63. In one embodiment, the end of the insulating coating 44 in the winding axis direction can be located in the range of -2 mm to +2 mm based on the lower end of the cut-off groove 63.

[0274] Multiple segments 61 can form multiple segments groups as they approach the outer periphery from the core side. At least one of the width, height, and spacing of segments belonging to the same segment group can be substantially the same. Preferably, the width, height, and spacing of segments belonging to the same segment group can be the same as each other.

[0275] Figure 7b The width D, height H, and separation interval P of the trapezoidal segment 61 are shown.

[0276] Reference Figure 7b In order to prevent the uncoated portion 43 near the bending point from being torn during bending and to ensure sufficient welding strength, the width D, height H and separation interval P of the section 61 are designed to sufficiently increase the number of overlapping layers of the uncoated portion 43 and to prevent abnormal deformation of the uncoated portion 43.

[0277] The cutting strip 61 is bent at or above the line G at the lower end of the cut-off groove 63. The cut-off groove 63 allows the cutting strip 61 to be bent smoothly and easily in the radial direction of the electrode assembly.

[0278] The width D of the segment 61 is defined as the length between two points where two straight lines extending from the two side edges 63b of the segment 61 intersect with a straight line extending from the bottom 63a of the cut-off groove 63. The height H of the segment 61 is defined as the shortest distance between the uppermost edge of the segment 61 and a straight line extending from the bottom 63a of the cut-off groove 63. The separation interval P of the segments 61 is defined as the length between two points where a straight line extending from the bottom 63a of the cut-off groove 63 intersects with a plurality of straight lines extending from the two side edges 63b connected to the bottom 63a. When the side edges 63b and / or the bottom 63a are curved, a tangent extending from the side edges 63b and / or the bottom 63a at the intersection of the side edges 63b and the bottom 63a can be used instead of a straight line.

[0279] Preferably, the width D of the cut piece 61 is 1 mm or more. If D is less than 1 mm, when the cut piece 61 is bent toward the core side, there may be areas or gaps where the cut piece 61 does not overlap to a degree that can sufficiently ensure the welding strength.

[0280] Preferably, the width D of the cut piece 61 can be adaptively adjusted according to the radius of the winding loop in which the cut piece 61 is located, so that the cut piece 61 overlaps well in the radial direction when it bends toward the core side of the electrode assembly.

[0281] Figure 7c The lower end of the segment 61, which defines the width D of the segment 61, is shown with reference to the core center O of the electrode assembly, when the electrode 60 is wound according to an embodiment of the present invention. Figure 7b line segment D ab The diagram of the arc A1A2 formed by the arc.

[0282] Reference Figure 7c Arc A1A2 has a length corresponding to the width D of the section 61, and has a circumferential angle Φ with reference to the core center of the electrode assembly. The circumferential angle Φ can be defined as the angle between two line segments connecting the two ends of arc A1A2 and the core center O on a plane perpendicular to the winding axis passing through arc A1A2.

[0283] When the lengths of arcs A1A2 of segment 61 are the same, the circumferential angle Φ decreases as the radius r of the winding loop in which segment 61 is located increases. Conversely, when the circumferential angle Φ of segment 61 is the same, the length of arc A1A2 increases proportionally as the radius r of the winding loop in which segment 61 is located increases.

[0284] The circumferential angle Φ affects the bending quality of the section 61. In the attached diagram, the solid arrow indicates the direction of the force applied to bend the section 61, and the dashed arrow indicates the direction in which the section 61 is bent. The bending direction is towards the core center O.

[0285] To improve the uniformity of bending and prevent cracks, the circumferential angle Φ of the cut piece 61 can be less than 45 degrees, preferably less than 30 degrees, depending on the radius r of the winding loop in which the cut piece 61 is located.

[0286] In one aspect, the circumferential angle Φ of the cut-off piece 61 may gradually or gradually increase or decrease along the radial direction of the electrode assembly within the aforementioned numerical range. In another aspect, the circumferential angle Φ of the cut-off piece 61 may gradually or gradually increase or gradually or gradually decrease along the radial direction of the electrode assembly within the aforementioned numerical range, or vice versa. Furthermore, in yet another aspect, the circumferential angle Φ of the cut-off piece 61 may be substantially the same along the radial direction of the electrode assembly within the aforementioned numerical range.

[0287] According to experiments, if the circumferential angle Φ of the cut piece 61 exceeds 45 degrees, the bending shape of the cut piece 61 will be uneven. The difference in force applied to the middle part and the side part of the cut piece 61 becomes larger, so the pressure on the cut piece 61 is uneven in the circumferential direction. Furthermore, if the pressing force is increased to achieve uniform bending, cracks may appear in the uncoated part 43 near the cut groove 63.

[0288] In one embodiment, the circumferential angles Φ of the plurality of segments 61 included in the electrode 60 are substantially the same, and the width of the segments 61 may increase proportionally with the radius r of the winding loop in which the segments 61 are located. "Substantially the same" means completely identical or with a deviation of less than 5%.

[0289] For example, when arranging the segments 61 starting from a point on the winding coil with a radius of 22 mm, a core radius of 4 mm, and a radius of 7 mm, and assuming that the circumferential angle Φ of the multiple segments 61 is the same (all 28.6 degrees), as shown in Table 1 below, the width D of the segment 61 can increase proportionally to the radius r of the winding coil in which the segment 61 is located. That is, for every 1 mm increase in the radius r of the winding coil, the width of the segment 61 can increase at a substantially constant rate of 0.5 mm.

[0290]

[0291] Winding radius (mm) 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 22.0 Cutout width D (mm) 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 Inscribed angle (degrees) 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6 28.6

[0292] Preferably, the width D(r) of the slice 61, which is a winding loop with radius r and referenced to the core center O of the electrode assembly, can be determined within the range of the following mathematical formula 1:

[0293] <Mathematical Formula 1>

[0294] 1≤D(r)≤2*π*r / 360°*45°.

[0295] Preferably, as the radius r of the winding loop at which the segment 61, with reference to the core center of the electrode assembly, increases, the width D(r) of the winding direction of each of the plurality of segments 61 can gradually increase, increase in stages, or the opposite.

[0296] On the other hand, as the radius r of the winding loop at which the segment 61, with reference to the core center of the electrode assembly, increases, the width D(r) of the winding direction of each of the plurality of segments 61 can be gradually increased, increased in stages, or the opposite.

[0297] On the other hand, as the radius r of the winding loop at which the segment 61, with the core center of the electrode assembly as a reference, increases, the width D(r) of the winding direction of each of the multiple segments 61 can first gradually increase or increase in stages and then gradually decrease or decrease in stages, or vice versa.

[0298] On the other hand, as the radius r of the winding loop at which the segment 61, with reference to the core center of the electrode assembly, increases, within the range of 1 mm to 11 mm, the width D(r) of the winding direction of each of the multiple segments 61 can first gradually increase or increase in stages and then gradually decrease or decrease in stages, or vice versa.

[0299] On the other hand, as the radius r of the winding loop where the cut piece 61 is located increases, the rate of change of D(r) of the cut piece 61 may be the same or different.

[0300] On the other hand, as the radius r of the winding loop where the cut piece 61 is located increases, the rate of change of D(r) of the cut piece 61 is the same or different in the range of 1 mm to 11 mm.

[0301] Refer again Figure 7b The height H of the cut piece 61 can be 2mm or more. If D2 is less than 2mm, there may be areas or gaps where the cut piece 61 does not overlap to a degree that can adequately ensure the welding strength when it is bent toward the core.

[0302] The height H of the cut piece 61 can be determined based on the condition that the cut piece 61 will not obstruct the core when bent towards the core. Preferably, the height H of the cut piece 61 can be adjusted so that more than 90% of the core's diameter is open to the outside.

[0303] Preferably, the height H of the cut-off piece 61 depends on the radius of the winding loop where the cut-off piece 61 is located and the radius of the core, and can increase as it approaches the outer periphery from the core side.

[0304] In one embodiment, it is assumed that the height H of the cut piece 61 increases from h1 to h1 with the increase of the radius of the winding loop. N After N stages of incremental increase, it will include the k-th height h with slice 61.k The initial radius of the winding loop of slice 61 (where k is a natural number from 1 to N) is r. k The core has a radius of r c At that time, the height h1 to h2 of the slice 61 can be determined in a manner that satisfies the following mathematical formula 2. N :

[0305] <Mathematical Formula 2>

[0306] 2mm≤h k ≤r k –α*r c (Preferably, α is 0.90 to 1).

[0307] If the height h of the cutout 61 k If mathematical formula 2 is satisfied, even if the cut piece 61 bends towards the core, the core can still open more than 90% of its diameter to the outside.

[0308] In one example, the radius of the overall winding of electrode 60 is 22 mm, and the height of the piece 61 starts at 3 mm. Furthermore, whenever the radius of the winding containing piece 61 increases by 1 mm, the height of piece 61 increases sequentially to 3 mm, 4 mm, 5 mm, and 6 mm. In the remaining windings, the height can be maintained at a substantially constant 6 mm. That is, the radial width of the variable height range of piece 61 within the radius of the overall winding is 3 mm, and the remaining radial range corresponds to a uniform height range.

[0309] In this case, based on the radius r of the core of the electrode assembly c When α is 1, and the equality condition is applied in the inequality on the right, the starting radii r1, r2, r3, r4 of the winding loop containing the segments 61 with heights of 3mm, 4mm, 5mm, and 6mm can be the same as those in Table 2 below.

[0310]

[0311]

[0312] When the segment 61 is positioned at the radius shown in Table 2, even if multiple segments 61 bend towards the core, the core will not be obscured by the segment 61. On the other hand, r1, r2, r3, and r4 shown in Table 2 can be offset towards the core based on the value of α. In one example, when α is 0.90, r1, r2, r3, and r4 can be offset towards the core by 10% of the core radius. In this case, when the segment 61 bends towards the core, 10% of the core radius is obscured by the segment 61. The r1, r2, r3, and r4 shown in Table 2 are the limit values ​​for the starting position of the segment 61. Therefore, the position of the segment 61 can be offset by a specified distance towards the outer periphery of the radius shown in Table 1.

[0313] Figure 7d It is a diagram schematically showing the relationship between the heights h1, h2, h3, h4 of the segment 61, the core radius rc, and the radii r1, r2, r3, r4 of the winding loop where the segment 61 begins to appear.

[0314] Refer to Table 2 and Figure 7d For example, when the radius r of the core C c When the height is 3m, the starting radii r1, r2, r3, and r4 of the winding loops containing segments 61 with heights of 3mm (h1), 4m (h2), 5mm (h3), and 6mm (h4) can be 6mm, 7mm, 8mm, and 9mm, respectively. From the radius of 9mm to the last winding loop, the height of segment 61 can be maintained at 6mm. Furthermore, winding loops with radii smaller than 6mm (r1) may not contain segment 61. In this example, the segment 61 with a height of 3mm (h1) adjacent to the core C is formed from the winding loop with a radius of 6mm. Therefore, even if the corresponding segment 61 bends towards the core C, it only covers the radius range of 3mm to 6mm, thus not substantially obscuring the core C. According to the value of α in mathematical formula 2, the position of segment 61 can be determined from the core radius r... c It is shifted to the C side of the core by less than 10%.

[0315] In other embodiments, as the starting radius r of the winding loop at which the slice 61 is located, based on the core center of the electrode assembly, increases, the height of the slice 61 can be increased at the same or different rates.

[0316] Preferably, the height H of the cut-off piece 61 satisfies mathematical formula 2, while the maximum height of the cut-off piece 61 can be limited.

[0317] Figure 7e It is used to determine the maximum value (h) of the height H of the cut-off piece 61 within the variable height range of the cut-off piece 61. max Concept map.

[0318] Reference Figure 7e In the wound structure of the electrode assembly, electrode E1, including the slice 61, is radially opposed to electrode E2 of opposite polarity, separated by a separation membrane S. Both sides of electrode E1 are coated with an active material layer E. 1，active Both sides of electrode E2 are also coated with an active material layer E 2，active To achieve electrical insulation, the end S of the separation membrane S... end It can be obtained from the end E of electrode E2 2，end Extending further outward corresponds to the insulation gap W gap The length of the electrode. Furthermore, to achieve electrical insulation, the end of electrode E1 will not extend further outward than the end of electrode E2. Therefore, the lower end of the uncoated portion 43 needs to ensure that it corresponds to the insulation gap W. gapThe interval. Furthermore, when electrodes E1, E2, and the separation membrane S are wound together, the end S of the separation membrane S... end Meandering occurs. Therefore, in order to expose the section 61 to the outside of the separation membrane S, a range W equivalent to the minimum meandering allowance of the separation membrane S needs to be allocated in the uncoated portion 43. margin，min Furthermore, in order to cut the segment 61, a minimum cutting allowance W needs to be allocated at the end of the current collector foil. scrap，min Therefore, within the variable height range of slice 61, the maximum height h of slice 61 is... max This can be determined using the following mathematical expression 3. In mathematical expression 3, W... foil This corresponds to the width of the current collector foil before it is cut.

[0319] <Mathematical Formula 3>

[0320] h max =W foil –W scrap，min –W margin，min –W gap

[0321] Preferably, when the first electrode is the anode, the insulating gap W gap It can be from 0.2 mm to 6 mm. Furthermore, when the first electrode is a cathode, the aforementioned insulation gap W... gap It can be from 0.1mm to 2mm.

[0322] Preferably, the minimum chip removal margin W is... scrap，min The thickness can range from 1.5mm to 8mm. Based on the process of cutting the wafer 61, a minimum chip breaking allowance W may not be assigned. scrap，min For example, the cut-off groove 63 can be formed such that the upper edge of the cut-off piece 61 and the upper edge of the current collector foil coincide with each other. In this case, in mathematical formula 3, W scrap , min It can become 0.

[0323] Preferably, the minimum serpentine allowance W of the above-mentioned separation membrane margin，min It can be 0 to 1 mm.

[0324] In one example, the minimum chip allowance W scrap，min It is 1.5mm, the minimum serpentine allowance W of the separation membrane S. margin，min It can be 0.5 mm. Under these conditions, the width W of the current collector foil before forming the section 61... foil It is 8mm to 12mm, insulation gap W gap When the thickness is 0.6mm, 0.8mm, and 1.0mm, the maximum height h of the section 61 is calculated using the above mathematical formula 3. max The results are shown in Table 3.

[0325]

[0326]

[0327] Referring to Table 3 above, the maximum height h of slice 61 within the variable height range of slice 61 is... max It can be set to 10mm. Therefore, the height of the cut-off piece 61 in the variable height range satisfies mathematical formula 2, and can be increased in stages or gradually along the radial direction of the electrode assembly in the range of 2mm to 10mm.

[0328] Refer again Figure 7b The spacing P between the cut pieces 61 can be adjusted within the range of 0.05 to 1 mm. If the spacing P is less than 0.05 mm, cracks may appear in the uncoated portion 43 near the lower end of the cut groove 63 due to stress when the electrode 60 travels in processes such as winding. Conversely, if the spacing P exceeds 1 mm, areas or gaps may appear where the cut pieces 61 do not overlap each other to a degree that ensures sufficient weld strength when the cut pieces 61 are bent.

[0329] On the other hand, when the current collector 41 of the electrode 60 is made of aluminum, it is more preferable to set the separation interval P to 0.5 mm or more. When the separation interval P is 0.5 mm or more, even if the electrode 60 travels at a speed of 100 mm / sec or more under a tension of 300 gf or more during a winding process or the like, cracks can be prevented from appearing in the lower part of the cut-off groove 63.

[0330] According to the experimental results, when the current collector 41 of electrode 60 is an aluminum foil with a thickness of 15 μm and the spacing P is greater than 0.5 mm, no cracks will appear in the lower part of the cut-off groove 63 when electrode 60 travels under the above-mentioned walking conditions.

[0331] like Figure 7b As shown, a cut-off groove 63 is sandwiched between two adjacent segments 61 in the winding direction X. The cut-off groove 63 corresponds to the space created when the uncoated portion 43 is removed. Preferably, the corner portions at both ends of the lower part of the cut-off groove 63 have a turning shape. That is, the cut-off groove 63 includes a substantially flat bottom 63a and a chamfered portion 63c. The chamfered portion 63c connects the bottom 63a and the side edge 63b of the segment 61. In a variation, the bottom 63a of the cut-off groove 63 can be replaced with an arc shape. In this case, the multiple side edges 63b of the segment 61 can be gently connected by the arc shape of the bottom 63a.

[0332] The radius of curvature of the chamfered portion 63c can be greater than 0 and less than 0.5 mm, preferably greater than 0 and less than 0.1 mm, and more preferably 0.01 mm to 0.05 mm. When the radius of curvature of the chamfered portion 63c meets the above-mentioned numerical range, cracks can be prevented from appearing in the lower part of the cut-off groove 63 during the travel of the electrode 60 in the winding process or the like.

[0333] The lower interior angle θ of the multiple segments 61 can increase from the core side towards the outer periphery. The lower interior angle θ is the angle between a straight line extending from the bottom 63a of the cut groove 63 and a straight line extending from the side 53b of the segment 61. When the segments 61 are symmetrical, the lower interior angle θ on the left and right sides is substantially the same.

[0334] If the radius of the electrode assembly increases, the radius of curvature also increases. If the lower interior angle θ of the piece 61 increases along with the radius of the electrode assembly, the stress generated along the radial and circumferential directions can be alleviated when the piece 61 is bent. Furthermore, if the lower interior angle θ increases, the area overlapping with the inner piece 61 and the number of overlapping layers also increase when the piece 61 is bent, thereby ensuring uniform welding strength in both the radial and circumferential directions and forming a flat bending surface area.

[0335] Preferably, the lower interior angle θ can be determined by the radius of the winding loop where the segment 61 is located and the width D of the segment 61.

[0336] Figure 7f This is a schematic diagram used to illustrate the mathematical formula for determining the lower interior angle θ of segment 61.

[0337] Reference Figure 7f Ideally, the side of the segment 61 should be consistent with the two ends A and D of the connecting line segment AD and the line segment AE and line segment DE of the core center E corresponding to the width D of the segment 61.

[0338] When the side of the segment 61 extends in the most ideal direction, assuming that line segment EF is approximately the same as line segment AE and line segment DE, the lower interior angle θrefer of the segment 61 can be approximately determined using the following mathematical formula 4, based on the width D of the segment 61 and the radius r of the winding loop where the segment 61 is located.

[0339] <Mathematical Expression 4>

[0340]

[0341] The angle in mathematical formula 4 is the lower interior angle θ of the slice 61. referThe ideal reference angle. On the other hand, there is a separation distance P between adjacent segments 61 located on the same winding loop. The length of the separation distance P is denoted by p. Since the separation distance P exists between adjacent segments 61, a tolerance of 50% of the separation distance p can be assigned to the lower interior angle θ. That is, the width of the upper edge BC of segment 61 can be increased to a maximum of p / 2 of the upper edge B'C'. The lower interior angle θ' with tolerance can be expressed by the following mathematical formula 5. Lower interior angle θ refer The ideal reference angle is ∠BAG, and the lower interior angle θ' is the angle ∠B'AG', which has a tolerance based on the separation distance p. In equation 5, H is the height of the section 61, and p is equivalent to the separation distance.

[0342] <Mathematical Formula 5>

[0343]

[0344] Preferably, the lower interior angle θ of the segments 61 located in each winding loop of the electrode assembly can satisfy the following mathematical formula 6. If so, when multiple segments 61 are bent toward the core center of the electrode assembly, the multiple segments 61 adjacent in the circumferential direction will not interfere with each other, and the bending can be achieved smoothly.

[0345] <Mathematical Formula 6>

[0346]

[0347] In one example, with a wound structure forming an electrode 60 with a diameter of 22 mm and a core radius of 4 mm, the lower inner angle of the cut-off piece 61 can be increased in stages within the range of 60 to 85 degrees in the height variable range.

[0348] On the other hand, the lower left and lower right interior angles of the cut-off piece 61 may be different. Even so, it can be designed such that the lower interior angle θ on one side satisfies the aforementioned mathematical formula 6.

[0349] Refer again Figure 7a The width dB1 of the first portion B1 is designed such that when the segment 61 of the third portion B2 is bent toward the core side, the core of the electrode assembly is opened outward by more than 90% of its diameter. The width dB1 of the first portion B1 can increase proportionally to the bending length of the segment 61 of group 1. The bending length is equivalent to the length from the bending point to the upper edge of the segment 61. Preferably, when the electrode 60 is used to manufacture an electrode assembly for a cylindrical battery with a form factor of 4680, the width dB1 of the first portion B1 can be set to 180 mm to 350 mm, depending on the diameter of the electrode assembly core and the height of the segment 61 included in group 1.

[0350] The bending point of the cut piece 61 can be set at a point on the line passing through the lower end of the cutting groove 63 or at a point that is separated upwards by a predetermined distance from that line. Bending the cut piece 61 towards the core at a point separated by a predetermined distance from the lower end of the cutting groove 63 better achieves overlap of the cut pieces in the radial direction. When multiple cut pieces 61 are bent, with the center of the core as a reference, the outer cut piece presses against the inner cut piece. At this time, if the bending point is separated by a predetermined distance from the lower end of the cutting groove 63, the inner cut piece is pressed against the outer cut piece in the winding direction, better achieving overlap of the multiple cut pieces. Preferably, the separation distance of the bending point can be less than 1 mm. The minimum height of the cut piece is 2 mm, so the ratio of the separation distance of the bending point relative to the minimum height can be less than 50%.

[0351] In one embodiment, the width of each slab group can be designed to form the same winding loop that constitutes the electrode assembly. The winding loops can be counted with reference to the end of the first portion B1 when the electrode 60 is wound up.

[0352] In another variation, the width of each slab group can be designed to form at least one or more windings that constitute an electrode assembly.

[0353] In yet another variation, the width and / or height and / or spacing of segments 61 belonging to the same segment group may gradually and / or periodically and / or irregularly increase or decrease within the group or between adjacent segments.

[0354] Groups 1 to 8 are just examples of the segments included in the third part B2. The number of multiple groups, the number of segments 61 included in each group, and the width of the groups can preferably be adjusted so that the segments 61 overlap in multiple layers, so as to maximize the distribution of stress during the bending of the uncoated portion 43 and fully ensure the welding strength with the current collector.

[0355] In another variation, the height of the second part B3 can be gradually reduced or reduced in stages, just like in the first and second embodiments.

[0356] In another variation, the slicing structure of the third portion B2 can extend to the second portion B3 (refer to the dashed line). In this case, the second portion B3, like the third portion B2, can also include multiple segments. Preferably, the slicing structure of the second portion B3 can be substantially the same as the outermost group of segments located in the third portion B2. In this case, the width, height, and spacing of the multiple segments included in the second portion B3 and the third portion B2 can be substantially the same. In a variation, the width and / or height and / or spacing of the segments in the second portion B3 can be larger than that in the third portion B2.

[0357] In Part B2, with the winding direction of electrode 60 as the reference, the height of the cut piece 61 increases in stages (groups 1 to 7) and the height of the cut piece can be defined as the variable height range of the cut piece. The last cut piece group (group 8) can be defined as the height uniform range where the height of the cut piece is maintained uniformly.

[0358] That is, in the third part B2, when the height of the cut 61 increases in stages to h1 to h N At that time, it is configured with h1 to h N-1 The interval of the section 61 with a height of (N is the height index, a natural number greater than 2) corresponds to a height-variable interval, and the interval of the section 61 with a height of hN corresponds to a height-uniform interval. The ratio of the height-variable interval and the height-uniform interval relative to the length of the winding direction of the electrode 60 will be explained later with reference to a specific embodiment.

[0359] When electrode 60 is used to manufacture an electrode assembly for a cylindrical battery with a shape factor of 4680, the width dB1 of the first portion B1 can be 180–350 mm. The width of group 1 can be 35–40% of the width of the first portion B1. The width of group 2 can be 130–150% of the width of group 1. The width of group 3 can be 120–135% of the width of group 2. The width of group 4 can be 85–90% of the width of group 3. The width of group 5 can be 120–130% of the width of group 4. The width of group 6 can be 100–120% of the width of group 5. The width of group 7 can be 90–120% of the width of group 6. The width of group 8 can be 115–130% of the width of group 7. The width dB3 of the second portion B3 can be the same as the width of the first portion B1, which can be 180–350 mm.

[0360] The reason why the widths of groups 1 to 8 do not exhibit a fixed increasing or decreasing pattern is that although the width of the wafers gradually increases from group 1 to group 8, the number of wafers included in each group is limited to a predetermined number, and the electrode thickness varies in the winding direction. Therefore, the number of wafers may decrease within a specific wafer group. Consequently, the width of the group may exhibit an irregular variation as illustrated above, moving from the core side towards the outer periphery.

[0361] That is, in the circumferential direction of the electrode assembly, when the width of each of the three consecutive adjacent cut pieces in the winding direction is set to W1, W2 and W3 respectively, it is possible to include a combination of cut pieces that are smaller than W2 / W1 than W3 / W2.

[0362] In the specific examples above, groups 4 to 6 are equivalent to the above situation. The width ratio of group 5 relative to group 4 is 120-130%, and the width ratio of group 6 relative to group 5 is 100-120%, which is less than 120-130%.

[0363] According to another variation, when the uncoated portion 43 of electrode 60 has a truncated structure, such as Figure 7g As shown, electrode 60 may include a segment omission interval 64 that regularly or irregularly omits a portion of multiple segments.

[0364] Preferably, there can be multiple omitted sections 64. In one example, the width of the omitted section 64 can maintain a certain width as it approaches the outer periphery from the core side. In another example, the width of the omitted section 64 can increase or decrease regularly or irregularly as it approaches the outer periphery from the core side. Preferably, the height of the uncoated portion present in the omitted section 64 can correspond to the height of the first portion B1 and / or the second portion B3.

[0365] The number of segments 61 existing within the segment omission interval 64 can be at least one or more. For example... Figure 7g As shown, electrode 60 may include an uncoated portion, in which the number of segments 61 present between the segment omission portion 64 increases as it approaches the outer periphery from the core.

[0366] Preferably, such as Figure 7h As shown, the width of the cut-out interval 64 can be set such that when the electrode 60 is wound up, the multiple cuts located in each winding loop can be located in a pre-defined independent region 66 based on the core center C of the electrode assembly 65.

[0367] That is, when viewing the electrode assembly 65 in the winding axis direction, multiple segments 61 can be located within multiple independent regions 66 with the core center C as the reference. The number of independent regions 66 can be changed to two, three, four, five, etc.

[0368] Preferably, the independent regions 66 can be fan-shaped. In this case, the angles between the independent regions 66 can be substantially the same. Furthermore, the circumferential angle δ of the independent regions 66 can be 20 degrees or more, optionally 25 degrees or more, optionally 30 degrees or more, optionally 35 degrees or more, or optionally 40 degrees or more.

[0369] In the variation, the independent region 66 can have the shape of a geometric figure such as a positive direction, a rectangle, a parallelogram, or a trapezoid.

[0370] In this invention, the shape of the section 61 can be modified in various ways.

[0371] Figure 8a This is a top view showing the structure of the electrode 70 according to a fifth embodiment of the present invention.

[0372] Reference Figure 8a The shape of the section 61' of the electrode 70 in the fifth embodiment differs from that in the embodiments described above, but the rest of the configuration is substantially the same. Therefore, unless otherwise specified, the configuration of the fourth embodiment can also be applied in the fifth embodiment.

[0373] The slice 61' has a geometric shape in which the upper and lower parts are substantially the same width. Preferably, the slice 61' may have a quadrilateral shape.

[0374] Figure 8b This is a diagram showing the definition of the width, height, and spacing of the quadrilateral segment 61'.

[0375] Reference Figure 8b In order to prevent the uncoated portion 43 from tearing and to improve welding strength during bending, the width D, height H, and spacing P of the section 61' can be set to sufficiently increase the number of overlapping layers of the uncoated portion 43 and prevent abnormal deformation of the uncoated portion 43. Abnormal deformation refers to the uncoated portion below the bending point failing to maintain a straight line and sinking, resulting in irregular deformation.

[0376] The width D of the segment 61' is defined as the length between two points where two straight lines extending from the two sides of the segment 61' intersect with a straight line extending from the bottom 63a of the cut-off groove 63. The height H of the segment 61' is defined as the shortest distance between the uppermost edge of the segment 61' and the straight line extending from the bottom 63a of the cut-off groove 63. The separation interval P of the segment 61' is defined as the length between two points where a straight line extending from the bottom 63a of the cut-off groove 63 intersects with a plurality of straight lines extending from the two sides 63b connected to the bottom 63a. When the sides 63b and / or the bottom 63a are curved, the straight lines can be replaced by tangents extending from the sides 63b and / or the bottom 63a at the intersection of the sides 63b and the bottom 63a.

[0377] Preferably, the conditions regarding the width D, height H, and separation interval P of the segment 61' are substantially the same as those in the fourth embodiment described above, so repeated descriptions are omitted. It should be noted that the segment 61' has a quadrilateral shape, so the lower interior angle of the segment 61' can be fixed at 90 degrees.

[0378] Similar to electrode 60 in the fourth embodiment, as Figure 8c As shown, the electrode 70 according to the fifth embodiment may also include a cutout interval 64 in which a portion of a plurality of cuts is regularly or irregularly omitted.

[0379] Furthermore, when the electrode 70, including the section 64 with the omitted portion, is wound into an electrode assembly, such as Figure 7hAs shown, multiple slices can be located within multiple independent regions 66.

[0380] Similar to the fourth and fifth embodiments, when the third part B2 and the second part B3 include multiple segments 61, 61', the shape of each segment 61, 61' can be modified in various ways.

[0381] Preferably, the slit can be deformed into various shapes if at least one of the following conditions is met.

[0382] Condition 1: The width of the bottom part is greater than the width of the top part.

[0383] Condition 2: The width of the bottom part is the same as the width of the top part.

[0384] Condition 3: The width remains the same as it approaches the top from the bottom.

[0385] Condition 4: The width decreases as it approaches the top from the bottom.

[0386] Condition 5: The width first decreases and then increases as it approaches the top from the bottom.

[0387] Condition 6: The width first increases and then decreases as it approaches the top from the bottom.

[0388] Condition 7: As the body moves from the bottom to the top, the width first increases and then remains at a certain level.

[0389] Condition 8: As the body moves from the bottom to the top, the width first decreases and then maintains a certain width.

[0390] Condition 9: The interior angles on one side and the other side of the lower part are the same.

[0391] The interior angle can be defined as the angle formed by the sides of the slice, with the width direction of the lower part of the slice as a reference. When the side is curved, the interior angle is defined as the angle between the tangent drawn from the lowest point of the curve and the width direction of the lower part of the slice.

[0392] Condition 10: The interior angles on one side and the other side of the lower part are different.

[0393] Condition 11: The interior angles on one side and the other side of the lower part have acute, right, or obtuse angles respectively.

[0394] Condition 12: Symmetrical from left to right with respect to the take-up axis direction.

[0395] Condition 13: Asymmetrical from left to right, based on the take-up axis direction.

[0396] Condition 14: The side profile is a straight line.

[0397] Condition 15: The side is curved.

[0398] Condition 16: The sides bulge outwards.

[0399] Condition 17: The side bulges inward.

[0400] Condition 18: The upper and / or lower corners are structures where straight lines intersect.

[0401] Condition 19: The upper and / or lower corners are structures where straight lines intersect with curves.

[0402] Condition 20: The upper and / or lower corners are structures where curves intersect.

[0403] Condition 21: The upper and / or lower corners are steering structures.

[0404] Figure 9 This is a diagram schematically illustrating the shape of a section according to a variation of the present invention.

[0405] As shown in the figure, the slice can have various geometric shapes with the dashed lines connecting the bottom of the cut-off grooves on both sides as its base. The geometric shape has a structure connecting at least one straight line, at least one curve, or a combination thereof. In one example, the slice can have various shapes such as polygonal shapes, directional shapes, or combinations thereof.

[0406] Specifically, the cut can be a symmetrical trapezoidal shape. Asymmetrical trapezoidal shape parallelogram shape Triangle shape pentagonal shape arc shape Or elliptical shape

[0407] The form of the cut is not limited to Figure 9 The shape shown can be transformed into other polygons, other turning shapes, or combinations thereof, in order to satisfy at least one of conditions 1 to 21 above.

[0408] In the polygonal shape of the cutout as well as In the middle, the upper and / or lower corners can be in the form of intersecting straight lines or a turning shape (see enlarged reference shape). (The upper part and the lower corners).

[0409] In the polygonal shape of the cutout as well as and the curve shape of the section as well as In a geometric figure, the interior angles θ1 on one side and θ2 on the other side can be the same or different. Each interior angle θ1 can be an acute angle, a right angle, or an obtuse angle. An interior angle is the angle between the base and the side of a geometric figure. When the side is a curve, it can be replaced by a tangent line extending from the point where the base and side intersect.

[0410] The side shape of a polygonal segment can be varied.

[0411] In one example, the morphology of the cut Side and shape Similarly, it can be deformed into an outward-bulging curve, or into a shape... or Similarly, the deformation is a curve that bends inward toward the inside of the segment.

[0412] In another example, the truncated morphology Side and shape or Similarly, it can be modified into a bent straight line that curves inward toward the inside of the slice. Although not illustrated, the slice shape... The side can be deformed into a bent straight line that bulges outward.

[0413] The sectional morphology of various deformations occurring on the side as well as In the middle, the interior angles θ1 on one side and θ2 on the other side of the lower part can be the same or different from each other. The interior angles θ1 on one side and θ2 on the other side of the lower part can be any one of acute angle, right angle or obtuse angle.

[0414] The width of the slice can vary in various patterns as it approaches the top from the bottom.

[0415] In one example, the width of the slice can maintain a certain width as it approaches the top from the bottom (morphology). In another example, the width of the slice can gradually decrease as it approaches the top from the bottom (morphology). as well as In yet another example, the width of the slice can gradually decrease and then increase as it approaches the top from the bottom (morphology). as well as In yet another example, the width of the slice can gradually increase and then decrease as it approaches the top from the bottom (morphology). In yet another example, the width of the slice can gradually decrease as it approaches the top from the bottom and then maintain a certain width (morphology). Although not illustrated, the width of the slice can gradually increase as it moves from the bottom to the top, and then maintain a certain width.

[0416] On the other hand, Figure 9 In the shown cutaway shape, the flat polygonal shape at the top can be rotated 180 degrees. In one example, in the cutaway shape... or When rotated 180 degrees, the width of the slice can gradually increase as it approaches the top from the bottom. In another example, in the slice shape... When rotated 180 degrees, the width of the slice can initially maintain a certain width as it approaches the top, and then gradually increase with a lag.

[0417] In the above-described embodiments (various modifications), according to another aspect of the invention, the shapes of the segments 61 and 61' can be modified differently depending on the region of the third part B2. In one example, for areas of stress concentration, a chamfered shape (e.g., a semicircle, an ellipse, etc.) that facilitates stress dispersion can be applied, while for areas of relatively low stress, a polygonal shape with the largest possible area (e.g., a quadrilateral, a trapezoid, a parallelogram, etc.) can be applied.

[0418] In the aforementioned embodiments (various modifications), the slitting structure of the third part B2 can also be applied to the first part B1. It should be noted that if a slitting structure is applied to the first part B1, depending on the radius of curvature of the core, when the segments 61 and 61' of the third part B2 are bent, a reverse forming phenomenon may occur, where the ends of the first part B1 distort outwards. Therefore, preferably, a slitting structure is not applied to the first part B1, or even if a slitting structure is applied, considering the radius of curvature of the core, the width and / or height and / or spacing of the segments 61 and 61' are adjusted to be as small as possible to avoid reverse forming.

[0419] According to another aspect of the invention, after the electrodes 60 and 70 are wound into an electrode assembly, multiple segments exposed at the upper and lower parts of the electrode assembly are overlapped in multiple layers along the radial direction of the electrode assembly, thereby forming a bent surface area.

[0420] Figure 10a This is a schematic diagram showing a cross-section of the bent surface region F formed by bending the section 61 towards the core C side of the electrode assembly 80. Figure 10a In the diagram, only the left side of the cross-section of the bent surface region F is shown relative to the winding axis of the electrode assembly 80. The bent surface region F can be formed on both the upper and lower parts of the electrode assembly 80. Figure 10b This is a simplified upper perspective view of the electrode assembly 80 having a bent surface region F.

[0421] Reference Figure 10a as well as Figure 10bThe bent surface region F has a multi-layered structure with multiple segments 61 overlapping along the winding axis direction. The overlapping direction is the winding axis direction Y. Section ① is the segment omission section (first part) without segments, and sections ② and ③ are the sections containing the winding coils of segments 61. Section ② is a height-variable section where the height of the segments 61 is variable, and section ③ is a section where the height of the segments is uniformly maintained at the outer periphery of the early electrode assembly. The radial lengths of sections ② and ③ can vary, as will be explained later. On the other hand, the uncoated portion (second part) included in at least one winding coil, including the outermost winding coil, may not include the segment structure. In this case, the second part can be removed in section ③.

[0422] In interval ②, from radius r1 to r of electrode assembly 80 N Within the interval, the height of multiple segments 61 can range from the minimum height h1 (=h min (From the initial stage of change to the maximum height h) N (=h max The height-variable range of multiple slices 61 is r1 to r. N From radius r N Up to the radius R of the electrode assembly 80, the height of the section 61 is uniformly maintained at h. N Uniform height means that the height deviation is within 5%.

[0423] At any radius position within intervals ② and ③, the number of layers in slice 61 varies depending on the radius position. Furthermore, the number of layers in slice 61 can be determined based on the width of interval ②, the height of slice 61, and the minimum and maximum heights h1 and h2 of the slices within the variable interval. N-1 The number of layers of the segment 61 varies depending on the height change Δh of the segment 61. The number of segments intersecting the virtual line when a virtual line is drawn at any radius position of the electrode assembly 80 in the direction of the winding axis is obtained.

[0424] Preferably, by adjusting the height, width, and spacing of the segment 61 according to the radius of the winding ring containing the segment 61, the number of layers of the segment 61 can be optimized to meet the required welding strength of the current collector at each position in the bending surface region F.

[0425] First, through a specific embodiment, it is explained that when the minimum height h1 of the slice 61 is the same in the variable height range ②, the maximum height h of the slice 61 is used as the reference. N The change in the number of layers of section 61 varies along the radius of the bent surface region F.

[0426] Electrode assemblies according to Examples 1-1 to 1-7 were prepared. The radius of the multiple electrode assemblies in the various embodiments is 22 mm, and the core diameter is 4 mm. The anode and cathode included in the electrode assembly have… Figure 7a The electrode structure is shown. Specifically, the truncated section has a trapezoidal shape. The second portion B3 of the anode and cathode does not include the truncated section. The length of the second portion B3 accounts for 3% to 4% of the total length of the electrode. The anode, cathode, and separation membrane are arranged according to... Figure 2 The winding process is described. The number of winding turns is between 48 and 56, with 51 turns in several embodiments. The thicknesses of the anode, cathode, and separation membrane are 149 μm, 193 μm, and 13 μm, respectively. The thicknesses of the anode and cathode include the thickness of the active material layer. The thicknesses of the anode current collector and cathode current collector are 15 μm and 10 μm, respectively. The winding lengths of the anode and cathode are 3948 mm and 4045 mm, respectively.

[0427] In each embodiment, the minimum height of the slice 61 is set to 3 mm, so that the variable height range ② of the slice 61 starts from a radius of 5 mm. Furthermore, in each embodiment, the height of the slice 61 increases by 1 mm for every 1 mm increase in radius, and the maximum height of the slice 61 is varied from 4 mm to 10 mm.

[0428] Specifically, in Example 1-1, the height variable range ② of the slice 61 is 5mm to 6mm, and the height of the slice 61 can vary from a radius of 3mm to 4mm. In Example 1-2, the height variable range ② of the slice 61 is 5mm to 7mm, and the height of the slice 61 can vary from 3mm to 5mm. In Example 1-3, the height variable range ② of the slice 61 is 5mm to 8mm, and the height of the slice 61 can vary from 3mm to 6mm. In Example 1-4, the height variable range ② of the slice 61 is 5mm to 9mm, and the height of the slice 61 can vary from 3mm to 7mm. In Example 1-5, the height variable range ② of the slice 61 is 5mm to 10mm, and the height of the slice 61 can vary from 3mm to 8mm. In Example 1-6, the height variable range ② of the slice 61 is 5mm to 11mm, and the height of the slice 61 can vary from 3mm to 9mm. In Examples 1-7, the height variable range ② of the cutter 61 is 5mm to 12mm, and the height of the cutter 61 can vary from 3mm to 10mm. In Examples 1-1 to 1-7, the height of the cutter 61 is uniform from the radius to the outer perimeter, corresponding to the upper limit of the height variable range ②. In one example, in Examples 1-7, the height of the cutter 61 is uniformly 10mm from a radius of 12mm to 22mm. On the other hand, in the contrasting electrode assembly, the height of the cutter 61 remains a single height of 3mm from a radius of 5mm to a radius of 22mm.

[0429] Figure 10c This is a graph showing the results of counting the number of layers of the segments along the radial direction in the bent surface region F of the anode formed on the upper part of multiple electrode assemblies according to Examples 1-1 to 1-7 and the comparative example. The bent surface region of the cathode also shows substantially the same results. The horizontal axis of the graph is the radius relative to the core center, and the vertical axis is the number of layers of the segments counted at each radial point, as explained later. Figure 10d as well as Figure 10e The same applies to China.

[0430] Reference Figure 10c The uniformity interval b1 of the number of layers in the sectional sample appears in Examples 1-1 to 1-7 and Comparative Example 1. The uniformity interval b1 is the radius range of the flat area in each graph. The length of the uniformity interval b1 increases as the maximum height of the sectional sample decreases, and the uniformity interval b1' of the comparative example is the longest. On the other hand, the number of layers in the sectional sample increases as the maximum height hN of the sectional sample increases. That is, if the maximum height hN of the sectional sample increases... N Increasing the width of the variable height interval ② of the wafer increases the number of layers in the wafer, while conversely, decreasing the width of the uniform layer number interval b1. Outside the uniform layer number interval b1, a layer number reduction interval b2 is formed, where the number of layers in the wafer decreases with increasing radius. The layer number reduction interval b2 is a radius interval where the number of layers in the wafer decreases with increasing radius of the electrode assembly. The uniform layer number interval b1 and the layer number reduction interval b2 are adjacent along the radial direction and are complementary to each other. That is, if the length of one interval increases, the length of the other interval decreases. Furthermore, in the layer number reduction interval b2, the amount of reduction in the number of layers is proportional to the distance separated from the uniform layer number interval b1.

[0431] From the viewpoint of the number of layers in the cut pieces, the cut pieces within the uniform interval b1 of the number of layers in Examples 1-1 to 1-7 have a number of layers of 10 or more. The region where the number of layers in the cut pieces reaches 10 or more can be designated as a preferred welding target region. The welding target region is an area where at least a portion of the current collector can be welded.

[0432] In Examples 1-1 to 1-7, the uniform layer number interval b1 starts from the radius point of the variable height interval ② of the slice. That is, the variable height interval ② starts from a radius of 5 mm and extends outwards.

[0433] Table 4 below shows the calculated cut-off interval c (a) relative to the radius (ba) of the electrode assembly excluding the core, for the anode in Examples 1-1 to 1-7 and Comparative Example 1. Figure 10aThe results include: the ratio of the length of ①), the ratio of the length of the uniformly stacked interval b1 to the length f of the length f from the radius point (5mm) starting from the uniformly stacked interval to the outermost point (22mm) of the electrode assembly, the ratio of the length of the variable height interval d of the section to the length f of the length f from the radius point (5mm) starting from the uniformly stacked interval to the outermost point (22mm) of the electrode assembly, the ratio of the length h of the electrode region corresponding to the section omitted (first part B1) relative to the total length of the electrode, the ratio i of the length of the electrode region corresponding to the variable height interval relative to the total length of the electrode, and the ratio i of the electrode region corresponding to the uniform height interval relative to the total length of the electrode.

[0434] The cathode exhibits a difference of 0.1% to 1.2% in parameter h; otherwise, the remaining parameters are substantially the same as those of the anode. The sum of ratios h, i, and j shows a slight difference from 100%. This is because there is a section without a tab in the second portion B3, which corresponds to the uncoated portion on the outer periphery of the electrode. For example, in Example 1-1, there is no tab in the second portion B3, which corresponds to approximately 4% of the total electrode length. In Table 4, a to f are parameters based on the length in the radial direction, and h, i, and j are parameters based on the electrode length before the electrode is wound into an electrode assembly. Furthermore, the parameters corresponding to the ratios (%) are values ​​rounded to one decimal place. These settings are also the same in Tables 5 and 6, which are described later.

[0435]

[0436]

[0437] Referring to Examples 1-1 to 1-7 in Table 4, the number of layers in the stencil is 11 to 26, and the ratio d / f relative to the height variable range d of the radius range f containing the stencil is 6% to 41%. Furthermore, the ratio e / f relative to the uniform range e of the number of layers in the radius range f containing the stencil is 47% to 82%. Also, the stencil omission range c (excluding the core) is... Figure 10a The ratio c / (ba) of ①) is 15%. Furthermore, the ratio of the electrode region length corresponding to the cutout omission interval (first part B1) relative to the total electrode length is 6%, the ratio of the electrode region length corresponding to the height variable interval relative to the total electrode length is 3% to 32%, and the ratio of the electrode region length corresponding to the height uniform interval relative to the total electrode length is 59% to 87%.

[0438] The number of layers g in the uniform layer number range reaches 10 or more in Examples 1-1 to 1-7. The uniform layer number range e decreases as the height variable range d of the cut piece increases; however, the number of layers g of the cut piece increases in the uniform layer number range e. Preferably, the uniform layer number range e in which the number of layers g of the cut piece reaches 10 or more can be set as the welding target area.

[0439] The radius of the electrode assembly of the cylindrical battery with shape factors of 1865 and 2170 is approximately 9 mm to 10 mm. Therefore, for existing cylindrical batteries, it is not possible to ensure the radial length of the section f is within 17 mm, as in Examples 1-1 to 1-7, nor is it possible to ensure the length of the uniformly stacked section e with a stack number of 10 or more is within 8 mm to 14 mm. This is because in existing cylindrical batteries, when the core radius is designed to be the same as in Examples 1-1 to 1-7 (2 mm), the radius range of the section that can be configured is essentially only 7 mm to 8 mm. Furthermore, in existing cylindrical batteries, the winding length of the electrode is within 600 mm to 980 mm. Such a shorter electrode length is only about 15% to 24% of the electrode length used in Examples 1-1 to 1-7 (3948 mm for the anode and 4045 mm for the cathode). Therefore, the numerical ranges of parameters h, i, and j cannot be easily derived based on the existing design specifications of cylindrical batteries.

[0440] Secondly, specific embodiments are used to illustrate when the height of the slice is in the variable range ( Figure 10a The maximum height h of the section in ②) N At the same time, depending on the change in the minimum height h1 of the section, how the number of layers of the section changes along the radial direction of the bent surface region F.

[0441] The electrode assemblies in Examples 2-1 to 2-5 have a radius of 22 mm and a core C diameter of 4 mm. Within the variable height range of the section 61 ( Figure 10a (②) The minimum height h1 is the same, both are 4mm, and the maximum height h N The height of the electrode assembly sections in Examples 2-1 to 2-5 varies from 6mm to 10mm in increments of 1mm. Figure 10a The widths of (②) are 2mm, 3mm, 4mm, 5mm, and 6mm respectively, and the omitted sections are ( Figure 10a ①) is the radius range from 2mm to 6mm.

[0442] The electrode assemblies in Examples 3-1 to 3-4 have a radius of 22 mm and a core C diameter of 4 mm. Within the variable height range of the section 61 ( Figure 10a (②) The minimum height h1 is the same, both are 5mm, and the maximum height hN The height of the electrode assembly sections in Examples 3-1 to 3-4 varies from 7mm to 10mm in increments of 1mm. Figure 10a The widths of (②) are 2mm, 3mm, 4mm, and 5mm respectively, and the omitted sections are ( Figure 10a ①) is the radius range from 2mm to 7mm.

[0443] The electrode assemblies in Examples 4-1 to 4-3 have a radius of 22 mm and a core C diameter of 4 mm. Within the variable height range of the section 61 ( Figure 10a (②) The minimum height h1 is the same, both are 6mm, and the maximum height h N The height of the electrode assembly sections varied from 8mm to 10mm in increments of 1mm. Therefore, the variable height range of the sections in Examples 4-1 to 4-3 is... Figure 10a The widths of (②) are 2mm, 3mm, and 4mm respectively, and the omitted section of the cut is ( Figure 10a ①) is the radius range from 2mm to 8mm.

[0444] The electrode assemblies in Examples 5-1 and 5-2 have a radius of 22 mm and a core C diameter of 4 mm. Within the variable height range of the section 61 ( Figure 10a (②) The minimum height h1 is the same, both are 7mm, and the maximum height h N The height of the electrode assembly sections in Examples 5-1 to 5-2 varies from 9mm to 10mm in increments of 1mm. Figure 10a The widths of (②) are 2mm and 3mm respectively, and the omitted section of the cut is ( Figure 10a ①) is the radius range from 2mm to 9mm.

[0445] Figure 10d This is a graph showing the results of counting the number of layers of a cross-section measured in the radial direction in the bent surface region F of the anode formed on the upper part of multiple electrode assemblies for Examples 2-1 to 2-5, Examples 3-1 to 3-4, Examples 4-1 to 4-3, and Examples 5-1 to 5-2. The bent surface region of the cathode also shows substantially the same results.

[0446] exist Figure 10dFigure (a) shows the results of counting the number of layers of the segment along the radial direction in the bending surface region F for Examples 2-1 to 2-5; Figure (b) shows the results of counting the number of layers of the segment along the radial direction in the bending surface region F for Examples 3-1 to 3-4; Figure (c) shows the results of counting the number of layers of the segment along the radial direction in the bending surface region F for Examples 4-1 to 4-3; and Figure (d) shows the results of counting the number of layers of the segment along the radial direction in the bending surface region F for Examples 5-1 to 5-2.

[0447] Reference Figure 10d The uniform stacking interval b1 of the slice appears together in multiple embodiments. The uniform stacking interval b1 is the radius range of the flat area in the graph. When the minimum height h1 of the slice is the same, the length of the uniform stacking interval b1 increases with the maximum height h of the slice. N The decrease leads to an increase. Furthermore, at the maximum height h of the cut section... N At the same time, the length of the uniform stacking interval b1 increases as the minimum height h1 of the slice decreases. On the other hand, within the uniform stacking interval b1, the stacking number of the slice increases with the maximum height h1 of the slice. N The number of layers increases with the increase in the number of layers. In several embodiments, a layer number decreasing interval b2 appears adjacent to the uniform layer number interval b1.

[0448] In several embodiments, the number of layers in the cut pieces within the uniform layer number interval b1 is 10 or more. Preferably, the region where the number of layers in the cut pieces is 10 or more can be designated as the preferred welding target region.

[0449] In several embodiments, the uniformity interval of the number of layers b1 varies from the variable height interval of the sectional section ( Figure 10a Starting from the radius point (②). In Examples 2-1 to 2-5, the height range of the section is variable ( Figure 10a (②) extends outwards from 6mm. In Examples 3-1 to 3-4, the height of the section is variable ( Figure 10a (②) extends outwards from 7mm. In Examples 4-3 to 4-4, the height of the section is variable ( Figure 10a ②) extends outwards from 8mm. In Examples 5-1 to 5-2, the height of the section is variable ( Figure 10a ②) starts from 9mm and extends outwards.

[0450] Table 5 below shows the results for various parameters calculated for Examples 2-1 to 2-5, Examples 3-1 to 3-4, Examples 4-1 to 4-3, and Examples 5-1 to 5-2, including the ratio e / f of the length of the uniform number of layers interval relative to the length from the radius point (6mm, 7mm, 8mm, 9mm) starting from the uniform number of layers interval to the outermost point (22mm) of the electrode assembly, and the ratio d / f of the length of the variable section height interval ② relative to the length from the radius point (6mm, 7mm, 8mm, 9mm) starting from the uniform number of layers interval to the outermost point (22mm) of the electrode assembly.

[0451] Table 5

[0452]

[0453] and Figure 10a as well as Figure 10d Referring together to Examples 2-5, 3-4, 4-3, and 5-2 in Table 5, in the variable height range ② of the slice, the maximum height h of the slice is... N All measurements are 10mm, but the minimum height h1 of the cut pieces is 4mm, 5mm, 6mm, and 7mm, each increasing by 1mm. The length of the variable height interval ② is 6mm, 5mm, 4mm, and 3mm, each decreasing by 1mm. In the four embodiments, the ratio e / f of the uniform number of layers is highest in embodiments 2-5 at 69%, and lowest in embodiments 5-2 at 38%. The number of layers in the uniform number of layers intervals is the same.

[0454] According to the results shown in Table 5, when the maximum height h of the cut is... N At the same time, as the minimum height h1 of the slice decreases, the width of the uniform stacking interval increases proportionally with the expansion of the variable height interval ② of the slice. This is because the smaller the minimum length h1 of the slice, the closer the starting radius of the slice is to the core side, and the area of ​​the slice stacking expands towards the core side.

[0455] Referring to Table 5, the number of layers in the cut is 16 to 26, the ratio d / f of the variable height range ② of the cut is 13% to 38%, and the ratio e / f of the uniform number of layers range is 31% to 69%. Furthermore, the ratio c / (ba) of the cut omitted range (①) relative to the radius (ba) of the electrode assembly excluding the core is 20% to 35%. Also, the ratio of the length of the electrode region corresponding to the cut omitted range (①) relative to the total electrode length is 10% to 20%, the ratio of the length of the electrode region corresponding to the variable height range (②) relative to the total electrode length is 6% to 25%, and the ratio of the length of the electrode region corresponding to the uniform height range (③) relative to the total electrode length is 62% to 81%.

[0456] The electrode assembly of a cylindrical battery with shape factors of 1865 and 2170 has a radius of approximately 9 mm to 10 mm. Therefore, it is not possible to ensure the radial length of the cut section f is between 13 mm and 16 mm as in some embodiments, and it is not possible to omit the cut section c ( Figure 10a The length of ①) ensures that the number of layers in the slice reaches 10 or more within a uniform range of 4mm to 7mm, and the length of e is ensured to be within a range of 5mm to 11mm. This is because in existing cylindrical batteries, when the core radius is designed to be the same as in several embodiments at 2mm, the radius range of the slice can be configured to be only 7mm to 8mm. Furthermore, in existing cylindrical batteries, the winding length of the electrode is between 600mm and 980mm. Such a short electrode length is only about 15% to 24% of the electrode length in several embodiments (3948mm for the anode and 4045mm for the cathode). Therefore, the numerical ranges of parameters h, i, and j cannot be easily derived based on the design specifications of existing cylindrical batteries.

[0457] Secondly, specific embodiments are used to illustrate the variable height range of the cut section ( Figure 10a (②) When the minimum height h1 and maximum height h of the cut-off piece N At the same time, depending on the core C diameter of the electrode assembly, how the number of layers of the sectional section changes along the radial direction of the bent surface region F.

[0458] The electrode assemblies of Examples 6-1 to 6-6 have a radius of 22 mm and a core C radius of 4 mm. Within the variable height range (②) of the cut piece 61, the minimum height h1 of the cut piece is the same (3 mm), while the maximum height hN of the cut piece varies from 5 mm to 10 mm in 1 mm increments. Therefore, the widths of the variable height range (②) of the cut pieces in Examples 6-1 to 6-6 are 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the omitted cut piece range (①) is a radius range from 4 mm to 7 mm.

[0459] The radius of the electrode assemblies in Examples 7-1 to 7-6 is 22 mm, and the radius of the core C is 2 mm. Within the variable height range (②) of the cut piece 61, the minimum height h1 of the cut piece is the same (3 mm), while the maximum height hN of the cut piece varies from 5 mm to 10 mm in 1 mm increments. Therefore, the widths of the variable height range (②) of the cut pieces in Examples 7-1 to 7-6 are 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively. The omitted cut piece range ① is a radius range from 2 mm to 5 mm, all of which are identical.

[0460] Figure 10e This is a graph showing the results of counting the number of layers of segments measured in the radial direction in the bent surface region F of the anode formed on the upper part of the electrode assembly for Examples 6-1 to 6-6 and Examples 7-1 to 7-6. Substantially similar results are shown in the bent surface region of the cathode.

[0461] exist Figure 10e Figure (a) shows the results of counting the number of layers of the segments measured in the radial direction in the bending surface region F for Examples 6-1 to 6-6, and Figure (b) shows the results of counting the number of layers of the segments measured in the radial direction in the bending surface region F for Examples 7-1 to 7-6.

[0462] Reference Figure 10e The uniform stacking interval b1 of the slices appears consistently across multiple embodiments. The uniform stacking interval b1 is the radius range of the flat area in the diagram. When the minimum height h1 of the slices is the same, the radial length of the uniform stacking interval b1 increases with the maximum height h1 of the slices. N The number of layers increases as the number of layers decreases. On the other hand, in the uniform layer number interval b1, the layer number of the sectional slice increases with the maximum height h of the sectional slice. N The number of layers increases with the increase in the number of layers. In several embodiments, a decreasing interval of the number of layers, b2, can be identified that is adjacent to the interval of uniform layer number, b1.

[0463] In several embodiments, within the uniform layer number range b1, the number of layers in the cut pieces is 10 or more. Preferably, the region where the number of layers in the cut pieces is 10 or more can be designated as the preferred welding target region.

[0464] In several embodiments, the uniform stacking interval b1 starts from the radius point of the variable height interval (②) of the slice. In embodiments 6-1 to 6-6, the radius of the variable height interval (②) of the slice is 7 mm, and in embodiments 7-1 to 7-6, the radius of the variable height interval (②) of the slice is 5 mm.

[0465] Table 6 below shows the results for various parameters calculated for Examples 6-1 to 6-6 and Examples 7-1 to 7-6, including the ratio e / f of the length of the uniform number of layers from the radius point 7mm and 5mm at the beginning of the uniform number of layers to the outermost point 22mm of the electrode assembly, and the ratio d / f of the length of the variable height interval ② of the cut piece from the radius point 7mm and 5mm at the beginning of the uniform number of layers to the outermost point 22mm of the electrode assembly.

[0466] Table 6

[0467]

[0468] Reference Figure 10a Compared with Examples 6-6 and 7-6 in Table 6, in the variable height range ② of the slice, the minimum height h1 and the maximum height hN of the slice are the same, which are 3 mm and 10 mm respectively. It should be noted that the core radius of Example 6-6 is 2 mm larger than that of Example 7-6. Therefore, compared with Example 7-6, the uniform number of layers range e and the slice range f of Example 6-6 are 2 mm smaller, and the number of layers of the slice is the same in the uniform number of layers range. This result is due to the difference in the core radius. According to the results shown in Table 6, when the width of the variable height range ② of the slice is the same, the smaller the core radius a, the smaller the ratio d / f of the variable height range ②, and conversely, the ratio e / f of the uniform number of layers range increases.

[0469] Referring to Table 6, the number of layers in the cut is 13 to 26, the ratio d / f of the variable height range ② of the cut is 12% to 47%, and the length ratio e / f of the uniform layer range is 40% to 76%. Furthermore, the ratio c / (ba) of the cut omitted range (①) relative to the radius ba of the electrode assembly excluding the core is 15% to 17%. Also, the ratio of the length of the electrode region corresponding to the cut omitted range (①) to the total electrode length is 6%, the ratio of the length of the electrode region corresponding to the variable height range (②) to the total electrode length is 7% to 32%, and the ratio of the length of the electrode region corresponding to the uniform height range (③) to the total electrode length is 59% to 83%.

[0470] The electrode assembly of a cylindrical battery with shape factors of 1865 and 2170 has a radius of approximately 9 mm to 10 mm. Therefore, it is not possible to ensure the radial length of the cut section f is between 15 mm and 17 mm as in some embodiments, and it is not possible to omit the cut section c ( Figure 10a The length of ①) ensures that the number of layers in the slice is uniformly within a range of 10 or more, with a layer count of at least 3 mm, and the length of e is ensured to be between 6 mm and 13 mm. This is because in existing cylindrical batteries, when the core radius is designed to be the same as in several embodiments (2 mm to 4 mm), the radius range of the slice can be configured to be only 5 mm to 8 mm. Furthermore, in existing cylindrical batteries, the winding length of the electrode is between 600 mm and 980 mm. Such a short electrode length is only about 15% to 24% of the electrode length in several embodiments (3948 mm for the anode and 4045 mm for the cathode). Therefore, the numerical ranges of parameters h, i, and j cannot be easily derived based on the design specifications of existing cylindrical batteries.

[0471] Taking into account the data in Tables 4 to 6, the number of layers in the uniform layer number range of the cut piece can be 11 to 26. Furthermore, the ratio d / f of the variable height range ② of the cut piece can be 6% to 47%. Furthermore, the ratio e / f of the uniform layer number range can be 31% to 82%. Furthermore, the ratio c / (ba) of the length of the cut piece omission range (①) to the radius of the electrode assembly excluding the core can be 15% to 35%. Furthermore, the ratio of the length of the electrode region corresponding to the cut piece omission range (①) to the total electrode length (winding direction length) can be 6% to 20%. Furthermore, the ratio of the length of the electrode region corresponding to the variable height range (②) of the cut piece to the total electrode length can be 3% to 32%. Furthermore, the ratio of the length of the electrode region corresponding to the uniform height range (③) of the cut piece to the total electrode length can be 59% to 87%.

[0472] On the other hand, the parameters described in Tables 4 to 6 can vary according to design factors including the core radius a; the electrode assembly radius b; the minimum height h1 and maximum height hN in the variable height range (②) of the cut section; the change in cut section height Δh for every 1 mm increase in radius; and the thickness of the anode, cathode, and separation membrane.

[0473] Therefore, the number of layers of the slice in the uniform layer number range can be expanded to 10 to 35. The ratio d / f of the variable height range (②) of the slice can be expanded to 1% to 50%. Furthermore, the ratio e / f of the uniform layer number range can be expanded to 30% to 85%. Furthermore, the ratio c / (ba) of the length of the slice omission range (①) relative to the radius of the electrode assembly excluding the core can be expanded to 10% to 40%. Furthermore, the ratio of the length of the electrode region corresponding to the slice omission range (①) relative to the total electrode length (winding direction length) can be expanded to 1% to 30%. Furthermore, the ratio of the length of the electrode region corresponding to the variable height range (②) of the slice to the total electrode length can be expanded to 1% to 40%. Furthermore, the ratio of the length of the electrode region corresponding to the uniform height range (①) of the slice to the total electrode length can be expanded to 50% to 90%. In the above embodiment, the maximum height (h) of the slice included in the variable height range (②) and the uniform height range (③) is... N The height index N is 2 to 8. For example, referring to Table 4, the height index N for Embodiments 1-1 and 1-7 is 2 and 8, respectively. However, the height index N in the radial direction of the electrode assembly can vary depending on the height variation Δh of the section. When the radial length of the variable height interval (②) is fixed, if the height variation Δh of the section decreases, the height index N increases accordingly, and vice versa. Preferably, the height index N is expanded to 2 to 20, and optionally, it is also expanded to 2 to 30.

[0474] In the bent surface regions F formed on the upper and lower parts of the electrode assembly, the uniformly stacked area can be used as the welding target area for the current collector.

[0475] Preferably, the welding area of ​​the current collector overlaps with the uniform stacking range of the electrode assembly by at least 50% in the radial direction, and the higher the overlap ratio, the better.

[0476] Preferably, in the welding area of ​​the current collector, the remaining area that does not overlap with the uniform stack number interval may overlap with the stack number reduction interval in the radial direction, wherein the stack number reduction interval is adjacent to the uniform stack number interval.

[0477] More preferably, in the welding area of ​​the current collector, the remaining area that does not overlap with the uniform stacking interval can overlap with the area where the overlap number of the slices in the decreasing stacking interval is 10 or more.

[0478] Welding current collectors in areas with a stack number of 10 or more layers offers advantages in terms of weld strength and the ability to prevent damage to the separation membrane or active material layer during welding. This is particularly useful when using high-output lasers with high penetration characteristics to weld current collectors.

[0479] If laser welding is used to overlap sections with more than 10 uniformly stacked sections and current collectors, then even if the laser output is increased to improve the welding quality, the uniformly stacked sections will absorb most of the laser energy and form a weld. Therefore, it can prevent the separation film and active material layer under the bent surface area F from being damaged by the laser.

[0480] Furthermore, the number of layers in the laser-irradiated area exceeds 10, resulting in a weld with sufficient volume and thickness. Therefore, weld strength is adequately ensured, and the resistance at the weld interface is reduced to a level suitable for rapid charging.

[0481] When welding the current collector, the laser output can be determined based on the desired weld strength between the bent surface region F and the current collector. The weld strength increases proportionally to the number of layers in the section. This is because, with increasing layer count, the volume of the weld formed by the laser increases. The raw materials of the current collector and the section dissolve together to form the weld. Therefore, a larger weld volume results in a stronger bond between the current collector and the bent surface region, and a decrease in the contact resistance at the weld interface.

[0482] Preferably, the welding strength can be 2 kgf / cm. 2 The above is more preferably achieved at 4 kgf / cm 2 The maximum weld strength can vary depending on the output of the laser welding equipment. In one embodiment, preferably, the weld strength can be set at 8 kgf / cm².2 Hereinafter, it is more preferably set at 6 kgf / cm 2 The following is a summary. However, the present invention is not limited thereto.

[0483] When the welding strength meets the above-mentioned numerical range, even if strong vibrations are applied to the electrode assembly along the winding axis and / or radial direction, the physical properties of the welding interface will not decrease, the weld strength is large enough, and the resistance of the welding interface can be reduced.

[0484] The output of the laser used to meet the welding strength requirements varies depending on the laser equipment. It can be appropriately adjusted within the range of 250W to 320W or within 40% to 100% of the maximum laser output provided by the corresponding equipment.

[0485] Weld strength can be defined as the tensile force per unit area of ​​the current collector when it begins to separate from the bending surface region F (kgf / cm²). 2 Specifically, after welding the current collector is completed, a tensile force is applied to the current collector, and the force can be gradually increased. Once the tensile force exceeds a threshold, the section begins to separate from the weld interface. At this point, the tensile force applied to the current collector divided by the area of ​​the current collector corresponds to the weld strength.

[0486] In the bent surface region F, the slices are stacked with multiple layers. According to the above embodiments, the number of slices can be increased from a minimum of 10 to a maximum of 35.

[0487] The thickness of the anode current collector (foil) constituting the uncoated portion 43 can be in the range of 10 μm to 25 μm, and the thickness of the cathode current collector (foil) constituting the uncoated portion 43 can be in the range of 5 μm to 20 μm. Therefore, the bending surface region F of the anode can include a region with a total stacked thickness of 100 μm to 875 μm. Furthermore, the bending surface region F of the cathode can include a region with a total stacked thickness of 50 μm to 700 μm.

[0488] Figure 10f According to an embodiment of the present invention, the upper top view of the electrode assembly showing the uniform stacking interval b1 and the decreasing stacking interval b2 in the bent surface region F of the sections 61 and 61' is shown.

[0489] Referring to Figure 10, the area between the two circles represented by the thick solid line corresponds to the bent surface area F of the section, the area between the two circles represented by the dotted line corresponds to the uniform layer number interval b1 of the section with a layer number of 10 or more, and the outer area of ​​the uniform layer number interval b1 corresponds to the layer number decreasing interval b2.

[0490] In one example, if the current collector Pc is welded to the bent surface region F, then the current collector Pc Welding patterns W appear on the surface p Welding pattern W p It can be an arrangement of lines or dots. Welding pattern W p This corresponds to the welding area, which, along the radial direction, can overlap with the uniformly stacked interval b1 of the cut piece by more than 50%. Therefore, the welding pattern W... p A portion of the weld pattern W can be contained within the uniform stacking interval b1. p The remaining portion can be contained within the layer number reduction interval b1 outside the uniform layer number interval b1. Of course, to maximize weld strength and reduce the resistance of the weld area, the entire weld pattern W can also be made... p It overlaps with the uniform interval b1 of the stacking number.

[0491] The area of ​​the bent surface region F can be defined as the sum of the areas of the uniform stacking interval b1 and the areas of the stacking reduction interval b2 of the section. The ratio e / f of the uniform stacking interval b1 is 30% to 85%, preferably 31% to 82%, so the ratio of the area of ​​the uniform stacking interval b1 to the area of ​​the bent surface region F can be 9% (30 2 / 100 2 ) to 72% (85) 2 / 100 2 ), preferably 10% (31) 2 / 100 2 ) to 67% (82) 2 / 100 2 ).

[0492] Preferably, the edge of the portion of the current collector Pc that contacts the bent surface region F can cover the ends of the segments 61 and 61' bent towards the core C in the last winding of the height uniformity zone (③). In this case, a welding pattern W is formed while the segments 61 and 61' are pressed by the current collector Pc. p This allows the current collector Pc and the bent surface region F to bond firmly. As a result, the multiple segments 61, 61' stacked in the winding axis direction are closely attached to each other, thereby reducing the resistance at the welding interface and preventing the segments 61, 61' from levitizing.

[0493] On the other hand, the bending direction of the cut piece can also be opposite to the direction described above. That is, the cut piece can be bent from the core side to the outer periphery side. In this case, the pattern of change of the cut piece height along the winding direction (X-axis) can be opposite to the above-described embodiments (variable examples). For example, the height of the cut piece can decrease in stages as it approaches the outer periphery from the core. Furthermore, the structure applied to the first part B1 and the structure applied to the second part B3 can be switched with each other. Preferably, the pattern of change of the cut piece height can be designed such that the height of the cut piece decreases in stages as it approaches the outer periphery from the core side, and the end of the cut piece does not protrude beyond the outer periphery of the electrode assembly when the cut piece closest to the outer periphery of the electrode assembly is bent towards the outer periphery.

[0494] The electrode structures of the above-described embodiments (variable embodiments) can be applied to at least one of a first electrode and a second electrode of different polarities included in gel roll-type or other types of electrode assemblies known in the art. Furthermore, if the electrode structures of the above embodiments (variable embodiments) are applied to either the first electrode or the second electrode, a conventional electrode structure can be applied to the other electrode. Moreover, the electrode structures applied to the first electrode and the second electrode can be different and not identical to each other.

[0495] As an example, when the first electrode and the second cathode are respectively the anode and the cathode, any one of the multiple embodiments (multiple variations) can be used in the first electrode, and the existing electrode structure (see reference) can be used in the second electrode. Figure 1 ).

[0496] As another example, when the first electrode and the second cathode are the anode and the cathode, respectively, any one of the multiple embodiments (multiple variations) can be selectively applied to the first electrode, and any one of the multiple embodiments (multiple variations) can be selectively applied to the second electrode.

[0497] In this invention, the anodic active material coated on the anode and the cathode active material coated on the cathode can be any active material known in the art, without limitation.

[0498] In one example, the anolyte may include a material with the general chemical formula A[A] x M y O 2+z The alkali metal compound represented by (A includes at least one element selected from Li, Na, and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x ≥ 0, 1 ≤ x + y ≤ 2, -0.1 ≤ z ≤ 2; stoichiometric coefficients x, y, and z are selected in such a way that the compound maintains electrical neutrality).

[0499] In another example, the anode active material may be the alkali metal compound xLiM disclosed in US6,677,082, US6,680,143 and the like 1 O2-(1-x)Li2M 2 O3(M 1 includes at least one element having an average oxidation state of 3; M 2 includes at least one element having an average oxidation state of 4; 0≤x≤1).

[0500] In yet another example, the anode active material may be represented by the general chemical formula LiaM 1 x Fe 1-x M 2 yP 1-y M 3 zO 4-z (M 1 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg and Al; M 2 includes at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V and S; M 3 includes halogen elements optionally including F; 0<a≤2, 0≤x≤1, 0≤y<1, 0≤z<1; the stoichiometric coefficients a, x, y and z are selected in a manner that the compound maintains electrical neutrality) or a lithium metal phosphate represented by Li3M2(PO4)3 [M includes at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg and Al].

[0501] Preferably, the anode active material may include primary particles and / or secondary particles formed by agglomeration of primary particles.

[0502] In one example, a carbon material, lithium metal or lithium metal compound, silicon or silicon compound, tin or tin compound and the like can be used as the cathode active material. Metal oxides such as TiO2 and SnO2 with a potential less than 2V can also be used as the cathode active material. As the carbon material, low crystallinity carbon, high crystallinity carbon and the like can be used.

[0503] The separation membrane can be a porous polymer film, such as a porous polymer film made of polyolefin polymers such as ethylene monomer polymers, propylene monomer polymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers, used alone or in layers. Alternatively, the separation membrane can be made of common porous nonwoven fabrics, such as nonwoven fabrics composed of high-melting-point glass fibers or polyethylene terephthalate fibers.

[0504] At least one surface of the separation membrane may include a coating of inorganic particles. Furthermore, the separation membrane itself may be composed of a coating of inorganic particles. The particles constituting the coating may have a structure bonded to a binder, thereby creating an interstitial volume between adjacent particles.

[0505] Inorganic particles can be composed of inorganic materials with a dielectric constant of 5 or higher. As a non-limiting example, the aforementioned inorganic particles may include those selected from Pb(Zr, Ti)O3 (PZT), Pb... 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg3Nb) 2 / 3 At least one substance in the group consisting of O3-PbTiO3 (PMN-PT), BaTiO3, hafnia (HfO2), SrTiO3, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO and Y2O3.

[0506] The structure of the electrode assembly according to an embodiment of the present invention is described in detail below.

[0507] Figure 11 This is a cross-sectional view of a gel roll-type electrode assembly 80, which is cut along the Y-axis direction (wrap-up axis direction) and in which the electrode 40 of the first embodiment is applied to the first electrode (anode) and the second electrode (cathode).

[0508] Electrode assembly 80 can be arranged according to... Figure 2 The winding process described herein. For ease of explanation, the protruding structures of the first uncoated portion 43a and the second uncoated portion 43b extending beyond the separation membrane are shown in detail, while the winding structures of the first electrode, the second electrode, and the separation membrane are omitted. The first uncoated portion 43a, protruding upwards, extends from the first electrode, and the second uncoated portion 43b, protruding downwards, extends from the second electrode.

[0509] The variation patterns of the heights of the first uncoated portion and the second uncoated portions 43a and 43b are briefly illustrated. That is, the height of the uncoated portion can vary irregularly depending on the location where the cross-section is cut. For example, if the side or cutting groove 63 of the trapezoidal segments 61 and 61' is cut off, the height H of the uncoated portion in the cross-section is lower than the height of segments 61 and 61'. Therefore, it should be understood that the height of the uncoated portion shown in the drawings illustrating the cross-section of the electrode assembly corresponds to the height of the uncoated portion contained in each winding coil. Figure 7b as well as Figure 8b The average of H).

[0510] Reference Figure 11 The first uncoated portion 43a includes a first portion B1 adjacent to the core of the electrode assembly 80, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 80, and a third portion B2 sandwiched between the first portion B1 and the second portion B3.

[0511] The height (length in the Y-axis direction) of the second part B3 is relatively lower than the height of the third part B2. Therefore, it is possible to prevent the rolled edge of the battery casing from coming into contact with the second part B3 during the process of applying pressure near the second part B3, thus preventing an internal short circuit.

[0512] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (various variations).

[0513] The ends 81 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 80, for example, bent from the outer periphery to the core. In this case, the second portion B3 can be substantially left unbent.

[0514] Figure 12 This is a cross-sectional view of a gel roll-type electrode assembly 90, which is cut along the Y-axis direction (wrap-up axis direction) and in which the electrode 45 of the second embodiment is applied to the first electrode (anode) and the second electrode (cathode).

[0515] Reference Figure 12 The first uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 90, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 90, and a third portion B2 sandwiched between the first portion B1 and the second portion B3.

[0516] The height of the second part B3 is relatively lower than that of the third part B2, gradually decreasing or decreasing in stages from the core side towards the outer periphery. Therefore, it can prevent the rolled edge of the battery casing from coming into contact with the second part B3 and causing an internal short circuit during the pressurization process near the second part B3.

[0517] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (various variations).

[0518] The ends 91 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 90, for example, they can be bent from the outer periphery to the core. In this case, the outermost 92 of the second portion B3 can be substantially unbent.

[0519] Figure 13 It is a cross-sectional view of a gel roll type electrode assembly 100, which is cut along the Y-axis direction (winding axis direction) and any one of the multiple electrodes 50, 60, 70 of the third to fifth embodiments (multiple variations thereof) is applied to the first electrode (anode) and the second electrode (cathode).

[0520] Reference Figure 13 The uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 100, a second portion B3 adjacent to the outer peripheral surface of the electrode assembly 100, and a third portion B2 sandwiched between the first portion B1 and the second portion B3.

[0521] The height of the first part B1 is relatively lower than the height of the third part B2. Furthermore, the bending length of the innermost uncoated portion 43a in the third part B2 is the same as or shorter than the radial length R of the first part B1. The bending length H is equivalent to the distance from the bending point of the uncoated portion 43a to its upper end. In a modified example, the bending length H may be smaller than the sum of the radial length R of the first part B1 and 10% of the radius of the core 102.

[0522] Therefore, even if the third part B2 is bent, the core 102 of the electrode assembly 100 still has more than 90% of its diameter open to the outside. The core 102 is a cavity located at the center of the electrode assembly 100. If the core 102 is not blocked, there are no difficulties in the electrolyte injection process, improving the electrolyte injection efficiency. Furthermore, by inserting the core 102 into the welding fixture, the welding process between the current collector on the cathode (or anode) side and the battery casing (or rivet terminals) can be easily performed.

[0523] The height of the second part B3 is relatively lower than the height of the third part B2. Therefore, it is possible to prevent the rolled edge of the battery casing from coming into contact with the second part B3 during the process of applying pressure near the second part B3, thus preventing an internal short circuit.

[0524] In a variation, with Figure 13 Unlike other parts, the height of the second part, B3, can be gradually reduced or reduced in stages. Furthermore, in... Figure 13 The outer periphery of the third part B2 has the same height, but the height of the third part B2 can gradually increase or increase in stages from the boundary between the first part B1 and the third part B2 to the boundary between the third part B2 and the second part B3. When the third part B2 is divided into multiple segments, the range in which the height of the uncoated portion 43a changes corresponds to the variable height range of the segments. Figure 10a (②).

[0525] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (various variations).

[0526] The ends 101 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 100, for example, they can be bent from the outer periphery to the core. In this case, the first portion B1 and the second portion B3 are not substantially bent.

[0527] In the case where part B2 includes multiple segments, bending stress is relieved, preventing the uncoated portion 43a near the bending point from tearing or abnormally deforming. Furthermore, when the width and / or height and / or spacing of the segments are adjusted according to the numerical range described in the above embodiments, the multiple segments are overlapped into multiple layers to ensure sufficient weld strength when bending towards the core, preventing the formation of empty holes (voids) in the bending surface area.

[0528] Figure 14 This is a cross-sectional view of the electrode assembly 110 according to another embodiment of the present invention, cut along the Y-axis direction (winding axis direction).

[0529] Reference Figure 14 ,and Figure 13 Compared to electrode assembly 100, the height of the second part B3 of electrode assembly 110 is substantially the same as the outermost height of the third part B2, and the rest of the configuration is substantially the same.

[0530] Part B3 may include multiple segments. The configuration of the multiple segments is substantially the same as that of the fourth and fifth embodiments (multiple variations) concerning the electrode.

[0531] In the electrode assembly 110, the height of the first portion B1 is relatively lower than the height of the third portion B2. Furthermore, the bending length H of the innermost uncoated portion of the third portion B2 is the same as or shorter than the radial length R of the first portion B1. Preferably, the first portion B1 can be an abbreviated section without a cutout. Figure 10a (①). In a modified example, the bending length H can be smaller than the sum of the radial length R of the first part B1 and 10% of the radius of the core 102.

[0532] Therefore, even if the third part B2 is bent, more than 90% of the diameter of the core 112 of the electrode assembly 110 is open to the outside. If the core 112 is not blocked, there are no difficulties in the electrolyte injection process, improving the electrolyte injection efficiency. Furthermore, by inserting the core 112 into the welding fixture, the welding process between the current collector on the cathode (or anode) side and the battery casing (or terminals) can be easily performed.

[0533] In one variation, the structure in which the height of the third portion B2 gradually increases or increases in stages from the core side towards the outer periphery can be extended to the second portion B3. In this case, the height of the uncoated portion 43a can gradually increase or increase in stages from the boundary between the first portion B1 and the third portion B2 to the outermost surface of the electrode assembly 110.

[0534] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (various variations).

[0535] The ends 111 of the first uncoated portion 43a and the second uncoated portion 43b can be bent in the radial direction of the electrode assembly 110, for example, they can be bent from the outer periphery to the core. In this case, the first portion B1 is not bent.

[0536] In the case where the third part B2 and the second part B3 contain multiple segments, bending stress is relieved, thereby preventing the uncoated portions 43a and 43b near the bending point from tearing or abnormally deforming. Furthermore, when the width and / or height and / or spacing of the segments are adjusted according to the numerical range described in the above embodiments, the multiple segments are overlapped into multiple layers to ensure sufficient weld strength when bending towards the core, preventing the formation of empty holes (voids) in the bending surface area.

[0537] Figure 15 This is a cross-sectional view of the electrode assembly 120 according to another embodiment of the present invention, cut along the Y-axis direction (winding axis direction).

[0538] Reference Figure 15Electrode assembly 120 and Figure 13 The difference in electrode assembly 100 lies in the fact that the height of the third part B2 exhibits a pattern of gradually increasing or increasing in stages before decreasing; the remaining components are essentially the same. The radius range in which the height of the third part B2 changes can be considered as the variable height range of the slice. Figure 10a (②). In this case, the variable height range of the sectional piece can be designed to form a bending surface region F when the third part B2 is bent, forming a uniform range of sectional piece stack number of 10 or more within the preferred numerical range described above.

[0539] Such a height variation in the third part B2 can be achieved through the step pattern contained within the third part B2 (see reference). Figure 6 ) or adjust the cut (refer to) Figure 7a or Figure 8a This is achieved through a height-based approach.

[0540] In the electrode assembly 120, the height of the first portion B1 is relatively lower than the height of the third portion B2. Furthermore, the bending length H of the innermost uncoated portion in the third portion B2 is the same as or shorter than the radial length R of the first portion B1. The interval corresponding to the first portion B1 is equivalent to the omitted interval of the uncoated section (…). Figure 10a (①). In a modified example, the bending length H can be smaller than the sum of the radial length R of the first part B1 and 10% of the radius of the core 102.

[0541] Therefore, even if the third part B2 bends towards the core side, the core 122 of the electrode assembly 120 still has more than 90% of its diameter open to the outside. If the core 122 is not blocked, there are no difficulties in the electrolyte injection process, improving the electrolyte injection efficiency. Furthermore, by inserting the core 112 into the welding fixture, the welding process between the current collector on the cathode (or anode) side and the battery casing (or terminals) can be easily performed.

[0542] Furthermore, the height of the second portion B3 is relatively lower than the height of the third portion B2. Preferably, the second portion B3 may not form a truncated section. Therefore, it is possible to prevent the rolled edge of the battery casing from coming into contact with the second portion B3 during the process of applying pressure near the second portion B3, thus preventing an internal short circuit. In a modified example, the height of the second portion B3 may gradually decrease or decrease in stages towards the outer periphery.

[0543] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (various variations).

[0544] The ends 121 of the first uncoated portion 43a and the second uncoated portion 43b can be bent from the outer periphery of the electrode assembly 120 toward the core. In this case, the first portion B1 and the second portion B3 are not substantially bent.

[0545] In the case where part B2 comprises multiple segments, bending stress is relieved, preventing the uncoated portions 43a and 43b from tearing or deforming abnormally. Furthermore, when the width and / or height and / or spacing of the segments are adjusted according to the numerical range of the above embodiments, the multiple segments are overlapped into multiple layers to ensure sufficient weld strength when bending towards the core side, and no empty holes (voids) are formed in the bending surface area.

[0546] Figure 16 This is a cross-sectional view of the electrode assembly 130 according to another embodiment of the present invention, cut along the Y-axis direction (winding axis direction).

[0547] Reference Figure 16 Electrode assembly 130 and Figure 15 The difference between the electrode assembly 120 and the electrode assembly 130 is that the height of the second part B3 has a pattern of gradually decreasing or decreasing in stages from the boundary point between the second part B3 and the third part B2 toward the outermost surface of the electrode assembly 130, while the rest of the configuration is substantially the same.

[0548] Such a height change in the second part B3 can be achieved by incorporating the step pattern contained in the third part B2 (see reference). Figure 6 This can be achieved by expanding the pattern to the second part B3, while gradually or gradually reducing the height of the pattern towards the outer periphery. Furthermore, in another variation, the height change of the second part B3 can be achieved by expanding the segmented structure of the third part B2 to the second part B3, while gradually or gradually reducing the height of the segment towards the outer periphery.

[0549] In the electrode assembly 130, the height of the first portion B1 is relatively lower than the height of the third portion B2. Furthermore, the bending length H of the innermost uncoated portion in the third portion B2 is the same as or smaller than the radial length R of the first portion B1. The first portion B1 corresponds to the omitted section of the cut-off piece (without a cut-off piece). Figure 10a (①). In a modified example, the bending length H can be smaller than the sum of the radial length R of the first part B1 and 10% of the radius of the core 102.

[0550] Therefore, even if the third part B2 bends towards the core side, the core 132 of the electrode assembly 130 still has more than 90% of its diameter open to the outside. If the core 132 is not blocked, there are no difficulties in the electrolyte injection process, improving the electrolyte injection efficiency. Furthermore, by inserting the core 132 into the welding fixture, the welding process between the current collector on the cathode (or anode) side and the battery casing (or terminals) can be easily performed.

[0551] The second uncoated portion 43b has the same structure as the first uncoated portion 43a. In a variation, the second uncoated portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (various variations).

[0552] The ends 131 of the first uncoated portion 43a and the second uncoated portion 43b can be bent from the outer periphery of the electrode assembly 130 toward the core. In this case, the first portion B1 is not bent.

[0553] In the case where the third part B2 and the second part B3 include multiple segments, bending stress is relieved, and the uncoated portions 43a and 43b near the bending point are prevented from tearing or abnormally deforming. Furthermore, when the width and / or height and / or spacing of the segments are adjusted according to the numerical range of the above embodiments, multiple segments are overlapped into multiple layers to ensure sufficient weld strength when bending towards the core, and no empty holes (voids) are formed in the bending surface area.

[0554] On the other hand, in the above-described embodiments (various modifications), the ends of the first uncoated portion 43a and the second uncoated portion 43b can be bent from the core side to the outer periphery. In this case, the second portion B3 is designed to have no truncated section (the section without the cut). Figure 10a Preferably, the second part B3 does not bend outwards. Furthermore, the radial width of the second part B3 can be the same as or greater than the bending length of the outermost uncoated portion (or segment) of the third part B2. Only in this way, when the outermost uncoated portion (or segment) of the third part B2 bends outwards, will the end of the bent portion not protrude beyond the outer peripheral surface of the electrode assembly and into the inner surface of the battery casing. Furthermore, the variation pattern of the segment structure can be opposite to the above-described embodiments (various modifications). For example, the height of the segment can increase gradually or progressively from the core side towards the outer peripheral side. That is, from the outer peripheral side of the electrode assembly towards the core side, the segment omission intervals ( Figure 10a ①), the variable height range of the section ( Figure 10a ②) and the height uniformity range of the section ( Figure 10a (③), thereby making it possible for a uniform range of stacked number of slices of 10 or more to appear in the bent surface region within a preferred numerical range.

[0555] Various electrode assembly structures according to embodiments of the present invention can be applied to cylindrical batteries.

[0556] Preferably, the cylindrical battery can be, for example, a cylindrical battery with a shape factor ratio (the value of the diameter of the cylindrical battery divided by its height, i.e., defined as the ratio of diameter Φ to height H) that is approximately greater than a certain value. Here, the shape factor is a value representing the diameter and height of the cylindrical battery.

[0557] Preferably, the diameter of the cylindrical battery can be 40mm to 50mm, and the height can be 60mm to 130mm. The shape factor of the cylindrical battery according to one embodiment can be, for example, 46110, 4875, 48110, 4880, or 4680. In the numerical values ​​of the shape factor, the first two digits represent the diameter of the battery, and the remaining digits represent the height of the battery.

[0558] When using electrode assemblies with tabless structures in cylindrical batteries with a shape factor ratio exceeding 0.4, the stress applied radially to the uncoated portion is relatively large when bending it, making the uncoated portion prone to tearing. Furthermore, to ensure sufficient weld strength and reduce resistance when welding current collectors to the bending surface region of the uncoated portion, the number of layers of the uncoated portion needs to be sufficiently increased in the bending surface region. These requirements can be achieved using electrodes and electrode assemblies according to various embodiments (variables) of the present invention.

[0559] According to one embodiment of the present invention, the battery is a generally cylindrical battery, which may be a cylindrical battery with a diameter of about 46 mm, a height of about 110 mm, and a shape factor ratio of 0.418.

[0560] According to another embodiment, the battery is a generally cylindrical battery, which may be a cylindrical battery with a diameter of about 48 mm, a height of about 75 mm, and a shape factor ratio of 0.640.

[0561] According to another embodiment, the battery is a generally cylindrical battery, which may be a cylindrical battery with a diameter of about 48 mm, a height of about 110 mm, and a shape factor ratio of 0.436.

[0562] According to another embodiment, the battery is a generally cylindrical battery, which may be a cylindrical battery with a diameter of about 48 mm, a height of about 80 mm, and a shape factor ratio of 0.600.

[0563] According to another embodiment, the battery is a generally cylindrical battery, which may be a cylindrical battery with a diameter of about 46 mm, a height of about 80 mm, and a shape factor ratio of 0.575.

[0564] Previously, batteries with a form factor ratio of approximately 0.4 or less were used. That is, batteries such as 1865 and 2170 were previously used. In the case of an 1865 battery, the diameter is approximately 18 mm and the height is approximately 65 mm, resulting in a form factor ratio of 0.277. In the case of a 2170 battery, the diameter is approximately 21 mm and the height is approximately 70 mm, resulting in a form factor ratio of 0.300.

[0565] The cylindrical battery according to an embodiment of the present invention will now be described in detail.

[0566] Figure 17 This is a cross-sectional view of a cylindrical battery 140 according to an embodiment of the present invention, cut along the Y-axis.

[0567] Reference Figure 17 According to an embodiment of the present invention, a cylindrical battery 140 includes an electrode assembly 141 comprising a first electrode, a separation membrane and a second electrode, a battery casing 142 for housing the electrode assembly 141, and a sealing member 143 for sealing the open end of the battery casing 142.

[0568] The battery casing 142 is a cylindrical container with an opening at the top. The battery casing 142 is made of a conductive metal such as aluminum, steel, or stainless steel. A nickel coating may be formed on the surface of the battery casing 142. The battery casing 142 houses the electrode assembly 141 and the electrolyte within its inner space through the upper opening.

[0569] Electrolytes can be those with A + B - Salts with similar structures. Among them, A... + Including Li + Na + K + Ions consisting of basic metal cations or combinations thereof. Additionally, B... - Including the choice of F - Cl - ,Br - I - NO3 - N(CN)2 - BF4 - ClO4 - AlO4 - AlCl4 - PF6 - SbF6 - AsF6 - BF2C2O4 - BC4O8 - (CF3)2PF4- - (CF3)3PF3- (CF3)4PF2 - (CF3)5PF - (CF3)6P - CF3SO3 - C4F9SO3, CF3CF2SO3 -- (CF3SO2)2N - (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2)2CH - (SF5)3C - (CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - CH3CO2, SCN - and (CF3CF2SO2)2N - - Any one or more anions that constitute a group.

[0570] Electrolytes can also be used in organic solvents. Suitable organic solvents include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or mixtures thereof.

[0571] Electrode assembly 141 may have a gel roll shape, but the invention is not limited thereto. For example... Figure 2 As shown, an electrode assembly 141 can be manufactured by winding a stack of a lower separation membrane, a first electrode, an upper separation membrane, and a second electrode at least once in sequence, with the winding axis C as the reference.

[0572] The first and second electrodes have different polarities. That is, if one is anodic, the other is cathodic. At least one of the first and second electrodes may have an electrode structure according to the above-described embodiments (variables). Furthermore, the other of the first and second electrodes may have a conventional electrode structure or an electrode structure according to the embodiments (variables). The electrode pair included in the electrode assembly 141 is not limited to one, but may include two or more.

[0573] The upper and lower portions of the electrode assembly 141 respectively have a first uncoated portion 146a of the first electrode and a second uncoated portion 146b of the second electrode. The first electrode has the electrode structure of the first embodiment (modified example). Therefore, the height of the uncoated portion 146a is lower than that of the portion of the second portion B3 that has a different height. The second portion B3 is separated from the inner surface of the battery casing 142, especially from the rolled edge portion 147, by a predetermined distance. Therefore, the second portion B3 of the first electrode does not contact the battery casing 142 that is electrically connected to the second electrode, thereby preventing an internal short circuit in the battery 140.

[0574] The second uncoated portion 146b of the second electrode may have the same structure as the first uncoated portion 146a. In another variation, the second uncoated portion 146b may optionally have the uncoated portion structure of the electrode according to several embodiments (various variations).

[0575] The seal 143 may include a plate-shaped cover 143a, a first gasket 143b that provides airtightness and insulation between the cover 143a and the battery casing 142, and a connecting plate 143c that is electrically and mechanically connected to the cover 143a.

[0576] The cover 143a is a component made of a conductive metal material that covers the upper opening of the battery casing 142. The cover 143a is electrically connected to the uncoated portion 146a of the first electrode and electrically insulated from the battery casing 142 by the first pad 143b. Therefore, the cover 143a can function as the first electrode terminal, such as the anode, of the cylindrical battery 140.

[0577] The cover 143a is placed on the rolled edge 147 formed on the battery casing 142 and is fixed by the crimping part 148. A first gasket 143b may be sandwiched between the cover 143a and the crimping part 148 to ensure the airtightness of the battery casing 142 and to achieve electrical insulation between the battery casing 142 and the cover 143a. The cover 143a may have a protrusion 143d that protrudes upward from its center.

[0578] The battery casing 142 is electrically connected to the second uncoated portion 146b of the second electrode. Therefore, the battery casing 142 has the same polarity as the second electrode. If the second electrode is cathode, then the battery casing 142 is also cathode.

[0579] The battery casing 142 has a rolled edge portion 147 and a pressing portion 148 at its upper end. The rolled edge portion 147 is formed by pressing the outer perimeter of the battery casing 142 inward. The rolled edge portion 147 prevents the electrode assembly 141 housed inside the battery casing 142 from escaping through the upper opening of the battery casing 142, and also functions as a support portion for placing the seal 143.

[0580] The inner surface of the rolled edge 147 is separated from the second portion B3 of the first electrode by a predetermined distance. More specifically, the lower end of the inner surface of the rolled edge 147 is separated from the second portion B3 of the first electrode by a predetermined distance. Furthermore, the second portion B3 has a low height, so it is not substantially affected even when the battery casing 142 is pressed inward to form the rolled edge 147. Therefore, the second portion B3 is not subjected to pressure from the rolled edge 147 or other constituent elements, thereby preventing local deformation of the electrode assembly 141 and preventing short circuits inside the cylindrical battery 140.

[0581] Preferably, when the pressing depth of the rolled edge 147 is defined as D1, and the radial length from the inner surface of the battery casing 142 to the boundary point of the second part B3 and the third part B2 is defined as D2, the relationship D1≤D2 can be satisfied. In this case, when pressing the battery casing 142 to form the rolled edge 147, damage to the second part B3 is substantially prevented.

[0582] A crimping portion 148 is formed on the upper part of the rolled edge portion 147. The crimping portion 148 has a shape that extends and bends in a manner that surrounds the outer peripheral surface of the cover 143a disposed on the rolled edge portion 147 and a portion of the upper surface of the cover 143a.

[0583] The cylindrical battery 140 may also include a first current collector 144 and / or a second current collector 145 and / or an insulator 146.

[0584] The first current collector 144 is attached to the upper part of the electrode assembly 141. The first current collector 144 is made of a conductive metal such as aluminum, copper, steel, or nickel, and is electrically connected to the first uncoated portion 146a of the first electrode. This electrical connection can be achieved by soldering. The first current collector 144 may be connected to a lead wire 149. The lead wire 149 may extend upwards from the electrode assembly 141 and be attached to the connecting plate 143c, or it may be directly attached to the lower surface of the cover 143a. The lead wire 149 can be soldered to other components.

[0585] Preferably, the first current collector 144 can be integrally formed with the lead 149. In this case, the lead 149 can have a long plate-like shape extending outward from near the center of the first current collector 144.

[0586] The first current collector 144 may have a plurality of protrusions and depressions (not shown) radially formed on its lower surface. With the radial protrusions and depressions, the first current collector 144 can be pressed to press the protrusions and depressions into the first uncoated portion 146a of the first electrode.

[0587] The first current collector 144 is bonded to the end of the first uncoated portion 146a. The bonding between the first uncoated portion 146a and the first current collector 144 can be achieved, for example, by laser welding. Laser welding can be achieved by melting a portion of the current collector base material. In a modified example, the welding between the first current collector 144 and the first uncoated portion 146a can be performed with solder placed in place. In this case, the solder can have a lower melting point than the first current collector 144 and the first uncoated portion 146a. Resistance welding, ultrasonic welding, spot welding, etc., can be used instead of laser welding.

[0588] The lower surface of the electrode assembly 141 can be bonded to the second current collector 145. One side of the second current collector 145 is bonded to the second uncoated portion 146b by welding, and the opposite side is bonded to the inner bottom surface of the battery casing 142 by welding. The bonding structure between the second current collector 145 and the second uncoated portion 146b can be substantially the same as the bonding structure between the first current collector 144 and the first uncoated portion 146a.

[0589] The uncoated portions 146a and 146b are not limited to the structures shown in the figures. Therefore, in addition to having existing uncoated portion structures, the uncoated portions 146a and 146b may selectively have uncoated portion structures of electrodes according to various embodiments (various modifications).

[0590] Insulator 146 may cover the first current collector 144. Insulator 146 covers the first current collector 144 above the first current collector 144, thereby preventing direct contact between the first current collector 144 and the inner surface of the battery casing 142.

[0591] The insulator 146 has a lead hole 151 to allow the lead 149 extending upward from the first current collector 144 to be pulled out. The lead 149 is pulled out upward through the lead hole 151 and attached to the lower surface of the connecting plate 143c or the lower surface of the cover 143a.

[0592] The perimeter of the insulator 146 is sandwiched between the first current collector 144 and the rolled edge 147, which can fix the combination of the electrode assembly 141 and the first current collector 144. As a result, the movement of the combination of the electrode assembly 141 and the first current collector 144 in the winding axis direction Y of the battery 140 is restricted, thereby improving the assembly stability of the battery 140.

[0593] Insulator 146 may be made of an insulating polymer resin. In one example, insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0594] The battery casing 142 may also include a vent 152 formed on its lower surface. The vent 152 corresponds to a region on the lower surface of the battery casing 142 that is thinner than the surrounding area. The vent 152 is structurally more fragile than the surrounding area. Therefore, if the cylindrical battery 140 malfunctions and the internal pressure increases to a certain level, the vent 152 ruptures, allowing the gas inside the battery casing 142 to escape to the outside. The internal pressure at which the vent 152 ruptures can be approximately 15 kgf / cm². 2 Up to 35 kgf / cm 2 .

[0595] The vent 152 can be formed continuously or discontinuously in a circular pattern on the lower surface of the battery casing 142. In a modified example, the vent 152 can be formed as a straight line pattern or other patterns.

[0596] Figure 18 This is a cross-sectional view of a cylindrical battery 150 according to another embodiment of the present invention, cut along the Y-axis direction.

[0597] Reference Figure 18 Cylindrical battery 150 and Figure 17 The difference between the cylindrical battery 140 and the previous one is that the first uncoated portion 146a of the first electrode adopts the electrode structure of the second embodiment (modified example), but the rest of the configuration is substantially the same.

[0598] Reference Figure 18 The first uncoated portion 146a of the first electrode may have a shape in which the height of the second portion B3 gradually decreases or decreases in stages as it approaches the inner surface of the battery casing 142. Preferably, the virtual line connecting the uppermost end of the second portion B3 may have the same or similar shape as the inner surface of the rolled edge portion 147.

[0599] The second part B3 has an inclined surface. Therefore, when the second part B3 is pressed into the battery casing 142 to form the rolled edge 147, it is possible to prevent the second part B3 from being damaged by the rolled edge 147. Furthermore, it is possible to suppress the phenomenon of the second part B3 coming into contact with the battery casing 142 of a different polarity, thereby preventing an internal short circuit.

[0600] The remaining configuration of the cylindrical battery 150 is substantially the same as that of the embodiment (modified example) described above.

[0601] The uncoated portions 146a and 146b are not limited to the structures shown in the figures. Therefore, in addition to having existing uncoated portion structures, the uncoated portions 146a and 146b may selectively have uncoated portion structures of electrodes according to various embodiments (various modifications).

[0602] Figure 19 This is a cross-sectional view of the cylindrical battery 160 according to another embodiment of the present invention, cut along the Y-axis direction.

[0603] Reference Figure 19 The cylindrical battery 160 differs from the cylindrical batteries 140 and 150 described above in that it has the following structure: the lead 149 connected to the first current collector 144 is directly connected to the cover 143a of the sealing member 143 through the lead hole 151 of the insulator 146. The insulator 146 and the first current collector 144 are in close contact with the lower surface of the cover 143a. The remaining components are substantially the same.

[0604] In the cylindrical battery 160, the diameter of the first current collector 144 and the outermost diameter of the third portion B2 are smaller than the minimum inner diameter of the battery casing 142. Furthermore, the diameter of the first current collector 144 can be the same as or larger than the outermost diameter of the third portion B2.

[0605] Specifically, the minimum inner diameter of the battery casing 142 can be equivalent to the inner diameter of the battery casing 142 at the location where the rolled edge 147 is formed. In this case, the outermost diameter of the first current collector 144 and the third portion B2 is smaller than the inner diameter of the battery casing 142 at the location where the rolled edge 147 is formed. Furthermore, the diameter of the first current collector 144 can be the same as or larger than the outermost diameter of the third portion B2. The edge perimeter region of the insulator 146 is bent downwards and sandwiched between the second portion B3 and the rolled edge 147, enabling the assembly of the electrode assembly 141 and the first current collector 144 to be fixed.

[0606] Preferably, the insulator 146 includes a portion covering the second portion B3 and a portion covering the first current collector 144, and the portion connecting the two portions may have a shape that bends together with the bend of the rolled edge 147. The insulator 146 provides insulation between the inner surfaces of the second portion B3 and the rolled edge 147, and also provides insulation between the inner surfaces of the first current collector 144 and the rolled edge 147.

[0607] The first current collector 144 can be located at a position higher than the lower end of the rolled edge 147, and can be combined with the first portion B1 and the third portion B2. In this case, the pressing depth D1 of the rolled edge 147 is shorter than or the same as the distance D2 from the inner surface of the battery casing 142 to the boundary of the second portion B3 and the third portion B2. Therefore, the first portion B1, the third portion B2, and the first current collector 144 combined therewith can be located at a position higher than the lower end of the rolled edge 147. The lower end of the rolled edge 147 refers to the bend point B between the portion of the battery casing 142 that houses the electrode assembly 141 and the rolled edge 147.

[0608] The first part B1 and the third part B2 occupy the inner space in the radial direction of the rolled edge 147, thus minimizing the empty space between the electrode assembly 141 and the cover 143a. Furthermore, the connecting plate 143c, which originally occupied the empty space between the electrode assembly 141 and the cover 143a, is omitted. Therefore, the lead 149 of the first current collector 144 can be directly bonded to the lower surface of the cover 143a. According to the structure described above, reducing the empty space within the battery increases the energy density corresponding to the amount of empty space reduced.

[0609] In the cylindrical battery 160, similar to the above embodiment, the first current collector 144 and the second current collector 145 can be welded to the ends of the first uncoated portion and the second uncoated portion 146a, 146b, respectively.

[0610] The uncoated portions 146a and 146b are not limited to the structures shown in the figures. Therefore, in addition to having existing uncoated portion structures, the uncoated portions 146a and 146b may selectively have extreme uncoated portion structures according to various embodiments (various modifications).

[0611] Figure 20 This is a cross-sectional view of the cylindrical battery 170 according to another embodiment of the present invention, cut along the Y-axis.

[0612] Reference Figure 20 ,and Figure 17 Compared to the cylindrical battery 140 shown, the structure of the electrode assembly of the cylindrical battery 170 is substantially the same, except that the remaining structure is different.

[0613] Specifically, the cylindrical battery 170 includes a battery casing 171 through which terminals 172 are provided. Terminals 172 are provided through a through-hole formed in the closed surface (upper surface of the drawing) of the battery casing 171. Terminals 172 are riveted to the through-hole of the battery casing 171 with a second pad 173 made of insulating material placed in place. Terminals 172 protrude outwards in the direction of gravity and the opposite direction.

[0614] Terminal 172 includes a terminal protrusion 172a and a terminal insertion portion 172b. The terminal protrusion 172a protrudes outward from the closed surface of the battery casing 171. The terminal protrusion 172a may be located approximately at the center of the closed surface of the battery casing 171. The maximum diameter of the terminal protrusion 172a may be larger than the maximum diameter of the through hole formed in the battery casing 171. The terminal insertion portion 172b penetrates approximately at the center of the closed surface of the battery casing 171, thereby enabling electrical connection with the uncoated portion 146a of the first electrode. The lower edge of the terminal insertion portion 172b may be riveted to the inner surface of the battery casing 171. That is, the lower edge of the terminal insertion portion 172b may have a shape that curves toward the inner surface of the battery casing 171. The inner side of the lower edge of the terminal insertion portion 172b includes a flat portion 172c. The maximum diameter of the lower part of the riveted terminal insertion portion 172b can be larger than the maximum diameter of the through hole in the battery casing 171.

[0615] The flat portion 172c of the terminal insertion portion 172b can be soldered to the central portion of the first current collector 144 connected to the first uncoated portion 146a of the first electrode. Laser welding is preferred as the welding method, but other welding methods such as ultrasonic welding can be used instead.

[0616] An insulator 174 made of insulating material can be sandwiched between the first current collector 144 and the inner side of the battery casing 171. The insulator 174 covers the upper part of the first current collector 144 and the upper edge of the electrode assembly 141. This prevents the second part B3 of the electrode assembly 141 from contacting the inner side of the battery casing 171, which has a different polarity, and causing a short circuit.

[0617] The thickness of the insulator 174 corresponds to the distance between the upper surface of the first current collector 144 and the inner side of the blockage portion of the battery casing 171, or slightly greater. Therefore, the insulator 174 can contact the upper surface of the first current collector 144 and the inner side of the blockage portion of the battery casing 171.

[0618] The terminal insertion portion 172b of terminal 172 can be soldered to the first current collector 144 through a through hole in insulator 174. The diameter of the through hole formed in insulator 174 can be larger than the diameter of the riveting portion at the lower end of terminal insertion portion 172b. Preferably, the through hole allows the lower part of terminal insertion portion 172b and the second pad 173 to be exposed.

[0619] The second pad 173 is sandwiched between the battery casing 171 and the terminal 172, thereby preventing the battery casing 171 and the terminal 172, which have different polarities, from making electrical contact with each other. Thus, the upper surface of the battery casing 171, which has a generally flat shape, can function as the second electrode terminal (e.g., cathode) of the cylindrical battery 170.

[0620] The second pad 173 includes a pad protrusion 173a and a pad insertion portion 173b. The pad protrusion 173a is sandwiched between the terminal protrusion 172a of the terminal 172 and the battery casing 171. The pad insertion portion 173b is sandwiched between the terminal insertion portion 172b of the terminal 172 and the battery casing 171. The pad insertion portion 173b deforms together with the terminal insertion portion 172b during reveting, thereby allowing it to fit snugly against the inner surface of the battery casing 171. The second pad 173 may, for example, be made of an insulating polymer resin.

[0621] The exposed portion 173a of the second pad 173 may have a shape that extends to cover the outer peripheral surface of the exposed portion 172a of the terminal 172. When the second pad 173 covers the outer peripheral surface of the terminal 172, short circuits can be prevented during the process of attaching electrical connection components such as buses to the upper surface of the battery casing 171 and / or the terminal 172. Although not shown in the figures, the exposed portion 173a may have a shape that extends to cover not only the outer peripheral surface of the exposed portion 172a but also a portion of the upper surface.

[0622] When the second pad 173 is made of polymer resin, it can be thermally bonded to the battery casing 171 and the terminal 172. In this case, the airtightness of the interface between the second pad 173 and the terminal 172, as well as the interface between the second pad 173 and the battery casing 171, can be enhanced. On the other hand, when the exposed portion 173a of the second pad 173 has a shape that extends to the upper surface of the exposed portion 172a of the terminal, the terminal 172 can be integrally bonded to the second pad 173 by insert injection molding.

[0623] On the upper surface of the battery casing 171, the remaining area 175, excluding the area occupied by the terminal 172 and the second pad 173, corresponds to a second electrode terminal having the opposite polarity to the terminal 172.

[0624] The second current collector 176 is attached to the lower part of the electrode assembly 141. The second current collector 176 is made of conductive metals such as aluminum, steel, copper, and nickel, and is electrically connected to the second uncoated part 146b of the second electrode.

[0625] Preferably, the second current collector 176 is electrically connected to the battery casing 171. For this purpose, the second current collector 176 is fixed such that at least a portion of its edge is sandwiched between the inner surface of the battery casing 171 and the first pad 178b. In one example, at least a portion of the edge of the second current collector 176 can be fixed to the rolled edge 180 by welding while supported by the lower end face of the rolled edge 180 formed at the lower end of the battery casing 171. In a modified example, at least a portion of the edge of the second current collector 176 can be directly welded to the inner wall surface of the battery casing 171.

[0626] The second current collector 176 may have a plurality of protrusions and recesses (not shown) radially formed on the surface opposite to the second uncoated portion 146b. When the protrusions and recesses are formed, the second current collector 176 can be pressed to press the protrusions and recesses into the second uncoated portion 146b.

[0627] Preferably, the ends of the second current collector 176 and the second uncoated portion 146b can be joined by welding, for example by laser welding. Furthermore, the welded portions of the second current collector 176 and the second uncoated portion 146b can be separated by a predetermined interval towards the core C side, with reference to the inner surface of the rolled edge portion 180.

[0628] The seal 178 for sealing the lower open end of the battery casing 171 includes a plate-shaped cover 178a and a first gasket 178b. The first gasket 178b electrically separates the cover 178a from the battery casing 171. A crimping portion 181 simultaneously secures the edge of the cover 178a and the first gasket 178b. The cover 178a is provided with a venting portion 179. The configuration of the venting portion 179 is substantially the same as in the above-described embodiment (modified example). The lower surface of the cover 178a may be located above the lower end of the crimping portion 181. In this case, a space is formed at the lower part of the cover 178a, thereby facilitating venting. This is particularly useful when the cylindrical battery 170 is positioned with the crimping portion 181 oriented towards the direction of gravity.

[0629] Preferably, the cover 178a is made of a conductive metal. However, a first gasket 178b is sandwiched between the cover 178a and the battery casing 171, so the cover 178a does not have electrical polarity. The seal 178 mainly functions to seal the open end at the bottom of the battery casing 171 and to release gas when the internal pressure of the battery 170 increases above a threshold. The threshold for internal pressure is 15 kgf / cm². 2 Up to 35 kgf / cm 2.

[0630] Preferably, the terminal 172, which is electrically connected to the first uncoated portion 146a of the first electrode, is used as the first electrode terminal. Furthermore, the portion 175 of the upper surface of the battery casing 171, excluding the terminal 172, which is electrically connected to the second uncoated portion 146b of the second electrode via the second current collector 176, is used as a second electrode terminal with a polarity different from the first electrode terminal. Thus, with both electrode terminals located on the upper part of the cylindrical battery 170, electrical connection components such as busbars can be arranged only on one side of the cylindrical battery 170. This simplifies the battery pack structure and increases energy density. Furthermore, the portion 175 used as the second electrode terminal has a generally flat shape, ensuring sufficient connection area for connecting electrical connection components such as busbars. Therefore, the cylindrical battery 170 can reduce the resistance at the connection points of the electrical connection components to a preferred level.

[0631] On the other hand, the structure of the electrode assembly 141 and the structure of the uncoated part are not limited to the structure shown in the drawings, and can be replaced by the structures of the above-described multiple embodiments (multiple variations).

[0632] Figure 21 This is a cross-sectional view of the cylindrical battery 180 according to another embodiment of the present invention, cut along the Y-axis.

[0633] Reference Figure 21 The structure of the electrode assembly 141 of the cylindrical battery 180 is similar to... Figure 18 The cylindrical battery 150 shown is substantially the same, except that the remaining configuration is the same except for the electrode assembly 141. Figure 20 The cylindrical battery 170 shown is essentially the same.

[0634] Therefore, the configuration of the embodiments (modifications) of cylindrical batteries 150 and 170 can also be applied to cylindrical battery 180.

[0635] Furthermore, the structure of the electrode assembly 141 and the structure of the uncoated portion are not limited to the structure shown in the accompanying drawings, and can be replaced by the structures of the above-described multiple embodiments (multiple variations).

[0636] Figure 22 This is a cross-sectional view of the cylindrical battery 190 according to another embodiment of the present invention, cut along the Y-axis.

[0637] Reference Figure 22 Cylindrical battery 190 includes Figure 14 The electrode assembly 110 shown, apart from the electrode assembly 110, has the following configuration: Figure 17 The cylindrical battery 140 shown is substantially the same. Therefore, refer to... Figure 14 as well as Figure 17The same configuration described can also be applied to this embodiment.

[0638] Reference Figure 10a as well as Figure 22 The first uncoated portion and the second uncoated portions 146a and 146b of the electrode assembly 110 are bent in the radial direction of the electrode assembly 110, for example, bent from the outer peripheral side toward the core side, thereby forming a bent surface region F.

[0639] The first part B1 corresponds to the section a1, which is lower in height than other parts and has no section cut, so it will not bend towards the core.

[0640] Preferably, the bending surface region F from the core side to the outer periphery side may include a section of omitted sections a1, a section of variable height of sections a2, and a section of uniform height of sections a3.

[0641] like Figure 10c , Figure 10d as well as Figure 10e As shown, the bent surface region F includes a uniformly stacked interval b1 with a stacking number of 10 or more segments in a position adjacent to the segment omission interval a1.

[0642] The bent surface region F may also include a region b2 adjacent to the outer periphery of the electrode assembly 110 where the number of layers of the truncated piece decreases as it approaches the outer periphery. Preferably, the region b1 with a uniform number of layers can be set as the welding target region.

[0643] In the bent surface region F, the preferred numerical ranges for the ratio a2 / c of ​​the height-variable interval a2 to the radius region c containing the segment, the ratio b1 / c of ​​the uniform stacking interval b1 to the radius region c containing the segment, and the ratio of the area of ​​the bent surface region F to the area of ​​the uniform stacking interval b1 have already been described, so repeated descriptions are omitted.

[0644] The first current collector 144 can be laser-welded to the bent surface region F of the first uncoated portion 146a, and the second current collector 145 can be laser-welded to the bent surface region F of the second uncoated portion 146b. The welding method can be replaced by ultrasonic welding, resistance welding, spot welding, etc.

[0645] Preferably, more than 50% of the welding area W of the first current collector 144 and the second current collector 145 can overlap with the uniform layer number interval b1 of the bent surface region F. Optionally, the remaining area of ​​the welding area W can overlap with the reduced layer number interval b2 of the bent surface region F. From the perspectives of high welding strength, low resistance of the welding interface, and prevention of damage to the separation film or active material layer, it is more preferable when the welding area W overlaps entirely with the uniform layer number interval b1.

[0646] Preferably, the number of layers in the sectional section can be between 10 and 35, within the uniform layer number interval b1 that overlaps with the welding area W and the optionally decreasing layer number interval b2.

[0647] Alternatively, when the number of layers in the section of the reduced layer number interval b2 that overlaps with the welding region W is less than 10, the laser output for welding in the reduced layer number interval b2 can be lower than the laser output for welding in the uniform layer number interval b1. That is, when the welding region W overlaps with both the uniform layer number interval b1 and the reduced layer number interval b2, the laser output can be adjusted according to the number of layers in the section. In this case, the welding strength in the uniform layer number interval b1 can be greater than the welding strength in the reduced layer number interval b2.

[0648] In the bent surface regions F formed in the upper and lower parts of the electrode assembly 110, the radial lengths of the truncated section a1 and / or the variable height section a2 and / or the uniform height section a3 of the truncated section can be the same or different from each other.

[0649] The height of the first part B1 of the electrode assembly 110 is relatively lower than that of the other parts. Furthermore, as... Figure 14 As shown, the bending length H of the innermost uncoated portion in the third part B2 is smaller than the value of adding the radial length R of the first part B1 and 10% of the radius of the core 112.

[0650] Therefore, even if the first uncoated portion 146a is bent towards the core side, the core 112 of the electrode assembly 110 can still be open to the outside by more than 90% of its diameter. If the core 112 is not blocked, there are no difficulties in the electrolyte injection process, improving the electrolyte injection efficiency. Furthermore, by inserting the core 112 into the welding fixture, the welding process between the second current collector 145 and the battery casing 142 can be easily performed.

[0651] When the uncoated portions 146a and 146b have a slit structure, if the width and / or height and / or spacing of the multiple segments are adjusted to a value range that satisfies the above embodiment, when the multiple segments are bent, the multiple segments overlap to a multilayer that can ensure sufficient welding strength, and no empty space (gap) is formed in the bending surface area F.

[0652] Preferably, the first current collector 144 and the second current collector 145 may have a truncated section covering the height uniformity interval a3 of the first electrode and the second electrode, with the last winding bend (see reference). Figure 10fThe outer diameter of the ends of (61, 61'). In this case, welding can be performed while multiple segments forming the bent surface region F are uniformly pressed by the current collector, and the tight stacking of the segments can be well maintained after welding. A tight stacking state refers to... Figure 10a The diagram shows a state where there are virtually no gaps between the multiple segments. This tight stacking helps reduce the resistance of the cylindrical battery 190 to a level suitable for fast charging (e.g., below 4 milliohms).

[0653] The structures of the uncoated portions 146a and 146b can be modified to conform to the structures described in the above embodiments (various modifications). Furthermore, it is not limited to applying existing uncoated portion structures to either side of the uncoated portions 146a and 146b.

[0654] Figure 23 This is a cross-sectional view of the cylindrical battery 200 according to another embodiment of the present invention, cut along the Y-axis.

[0655] Reference Figure 23 Cylindrical battery 200 includes Figure 14 The electrode assembly 110 shown, apart from the electrode assembly 110, has the following configuration: Figure 21 The cylindrical battery 180 shown is substantially the same. Therefore, refer to... Figure 14 as well as Figure 21 The same configuration described can also be applied to this embodiment.

[0656] Reference Figure 10a as well as Figure 23 The first uncoated portion and the second uncoated portions 146a and 146b of the electrode assembly 110 are bent in the radial direction of the electrode assembly 110, for example, bent from the outer peripheral side toward the core side, thereby forming a bent surface region F.

[0657] The height of the first part B1 is lower than that of the other parts, corresponding to the omitted section a1 of the cut piece without a cut piece, so it will not bend towards the core.

[0658] Preferably, the bending surface region F from the core side to the outer periphery side may include a section of omitted sections a1, a section of variable height of sections a2, and a section of uniform height of sections a3.

[0659] like Figure 10c , Figure 10d as well as Figure 10e As shown, the bent surface region F includes a uniformly stacked interval b1 with a stacking number of 10 or more segments in a position adjacent to the segment omission interval a1.

[0660] The bent surface region F may also include a region b2 adjacent to the outer periphery of the electrode assembly 110 where the number of layers of the truncated piece decreases as it approaches the outer periphery. Preferably, the region b1 with a uniform number of layers can be set as the welding target region.

[0661] In the bent surface region F, the preferred numerical ranges of the ratio a2 / c of ​​the height variable interval a2 to the radius region c containing the segment, the ratio b1 / c of ​​the uniform stacking interval b1 to the radius region c containing the segment, and the ratio of the area of ​​the bent surface region F to the area of ​​the uniform stacking interval b1 have already been described, so repeated descriptions are omitted.

[0662] The first current collector 144 can be laser-welded to the bent surface region F of the first uncoated portion 146a, and the second current collector 176 can be laser-welded to the bent surface region F of the second uncoated portion 146b. The welding method can be replaced by ultrasonic welding, resistance welding, spot welding, etc. The welding area W of the second current collector 176 and the second uncoated portion 146b can be separated from the inner surface of the rolled edge portion 180 by a predetermined interval.

[0663] Preferably, more than 50% of the welding area W of the first current collector 144 and the second current collector 176 can overlap with the uniform layer number interval b1 of the bent surface region F. Optionally, the remaining area of ​​the welding area W can overlap with the reduced layer number interval b2 of the bent surface region F. From the perspectives of high welding strength, low resistance of the welding interface, and prevention of damage to the separation film or active material layer, it is more preferable when the welding area W overlaps entirely with the uniform layer number interval b1.

[0664] Preferably, the number of layers in the sectional section can be between 10 and 35, within the uniform layer number interval b1 that overlaps with the welding area W and the optionally decreasing layer number interval b2.

[0665] Alternatively, when the number of layers in the section of the reduced layer number interval b2 that overlaps with the welding region W is less than 10, the laser output used for welding in the reduced layer number interval b2 can be lower than the laser output used for welding in the uniform layer number interval b1. That is, when the welding region W overlaps with both the uniform layer number interval b1 and the reduced layer number interval b2, the laser output can be changed according to the number of layers in the section. In this case, the welding strength in the uniform layer number interval b1 can be greater than the welding strength in the reduced layer number interval b2.

[0666] In the bent surface regions F formed in the upper and lower parts of the electrode assembly 110, the radial lengths of the truncated section a1 and / or the variable height section a2 and / or the uniform height section a3 of the truncated section can be the same or different from each other.

[0667] The height of the first part B1 of the electrode assembly 110 is relatively lower than that of the other parts. Furthermore, as... Figure 14 As shown, the bending length H of the innermost uncoated portion in the third part B2 is smaller than the value of adding the radial length R of the first part B1 and 10% of the radius of the core 112.

[0668] Therefore, even if the uncoated portion 146a is bent towards the core, the core 112 of the electrode assembly 110 can still be open to the outside by more than 90% of its diameter. If the core 112 is not blocked, there are no difficulties in the electrolyte injection process, improving the electrolyte injection efficiency. Furthermore, by inserting the core 112 into the welding fixture, the welding process between the first current collector 144 and the terminal 172 can be easily performed.

[0669] When the first uncoated portion and the second uncoated portions 146a and 146b have a slitting structure, if the width and / or height and / or spacing of the multiple segments are adjusted to satisfy the numerical range of the above embodiment, when the multiple segments are bent, the multiple segments overlap to a multilayer that can sufficiently ensure the welding strength, and no empty space (gap) is formed in the bending surface area F.

[0670] Preferably, the first current collector 144 and the second current collector 176 may have a region that contacts the first uncoated portion and the second uncoated portion 146a, 146, covering the last loop of the bent section of the height uniform region a3 of the first electrode and the second electrode (see reference). Figure 10f The outer diameter of the ends of (61, 61'). In this case, welding can be performed while multiple segments forming the bent surface region F are uniformly pressed by the current collector, and the tight stacking of the segments can be well maintained after welding. A tight stacking state refers to... Figure 10a The diagram shows a state where there are virtually no gaps between the multiple segments. This tight stacking helps reduce the resistance of the cylindrical battery 200 to a level suitable for fast charging (e.g., below 4 milliohms).

[0671] The structures of the uncoated portions 146a and 146b can be modified to conform to the structures described in the above embodiments (various modifications). Furthermore, it is not limited to applying existing uncoated portion structures to either side of the uncoated portions 146a and 146b.

[0672] Figure 24 This is a cross-sectional view of the cylindrical battery 210 according to another embodiment of the present invention, cut along the Y-axis.

[0673] Reference Figure 24 Cylindrical battery 210 includes Figure 13The electrode assembly 100 shown, apart from the electrode assembly 100, has the following configuration: Figure 17 The cylindrical battery 140 shown is substantially the same. Therefore, refer to... Figure 13 as well as Figure 17 The same configuration described can also be applied to this embodiment.

[0674] Preferably, the first uncoated portion and the second uncoated portions 146a and 146b of the electrode assembly 100 are divided into multiple segments, which are bent in the radial direction of the electrode assembly 100, for example, bent from the outer periphery towards the core. In this case, the first portion B1 and the second portion B3 of the first uncoated portion 146a are lower in height than the other portions and do not contain segments, so they are not substantially bent. The same situation applies to the second uncoated portion 146b.

[0675] In this embodiment, the bent surface region F may also include, from the core side to the outer periphery, a section a1 with omitted segments, a section a2 with variable segment height, and a section a3 with uniform segment height. It should be noted that the second portion B3 is not bent, so the radial length of the bent surface region F can be shorter than in the embodiment described above.

[0676] like Figure 10c , Figure 10d as well as Figure 10e As shown, the bent surface region F includes a uniformly stacked interval b1 where the number of stacked pieces is 10 or more, located adjacent to the omitted section a1 of the truncated piece.

[0677] The bent surface region F may also include a region b2 adjacent to the second portion B3 of the electrode assembly 110 where the number of layers of the truncated piece decreases as it approaches the outer periphery. Preferably, the region b1 with a uniform number of layers can be set as the welding target area.

[0678] In the bent surface region F, the preferred numerical ranges of the ratio a2 / c of ​​the height variable interval a2 to the radius region c containing the segment, the ratio b1 / c of ​​the uniform stacking interval b1 to the radius region c containing the segment, and the ratio of the area of ​​the bent surface region F to the area of ​​the uniform stacking interval b1 have already been described, so repeated descriptions are omitted.

[0679] The first current collector 144 can be soldered to the bent surface region F of the first uncoated portion 146a, and the second current collector 145 can be soldered to the bent surface region F of the second uncoated portion 146b.

[0680] The overlap relationship between the uniform stacking interval b1 and the reduced stacking interval b2 and the welding area W, the outer diameter of the first current collector 144 and the second current collector 145, and the configuration of the first part B1 not blocking the core diameter of more than 10% are substantially the same as the above contents.

[0681] On the other hand, the second part B3 does not include the truncated piece, and its height is lower than that of the third part B2. Therefore, when the first uncoated part 146a is bent, the second part B3 does not bend substantially. Furthermore, the second part B3 is fully separated from the rolled edge part 147, thus solving the problem of damage to the second part B3 during the pressing of the rolled edge part 147.

[0682] The structures of the uncoated portions 146a and 146b can be modified to the structures described in the above embodiments (various modifications). Furthermore, it is not limited to applying the existing uncoated portion structure to either side of the uncoated portions 146a and 146b.

[0683] Figure 25 This is a cross-sectional view of the cylindrical battery 220 according to another embodiment of the present invention, cut along the Y-axis.

[0684] Reference Figure 25 Cylindrical battery 220 includes Figure 24 The electrode assembly 100 shown, apart from the electrode assembly 100, has the following configuration: Figure 21 The cylindrical battery 180 shown is substantially the same. Therefore, refer to... Figure 21 as well as Figure 24 The described structure can also be applied substantially the same to this embodiment.

[0685] Preferably, the first uncoated portion and the second uncoated portions 146a and 146b of the electrode assembly 100 are divided into multiple segments and bent from the outer periphery toward the core. In this case, the first portion B1 and the second portion B3 of the first uncoated portion 146a are lower in height than the other portions and do not include the segment structure, so they do not substantially bend toward the core. The same situation applies to the second uncoated portion 146b.

[0686] Therefore, in this embodiment, it is also related to Figure 24 Similarly, in the embodiment, the bending surface region F from the core side to the outer periphery may include a section a1 where the slice is omitted, a section a2 where the slice height is variable, and a section a3 where the slice height is uniform. It should be noted that the second part B3 is not bent, so the radial length of the bending surface region F can be shorter than in the embodiment described above.

[0687] like Figure 10c , Figure 10d as well as Figure 10eAs shown, the bent surface region F includes a uniformly stacked interval b1 where the number of stacked pieces is 10 or more, located adjacent to the omitted section a1 of the truncated piece.

[0688] The bent surface region F may also include a region b2 adjacent to the second portion B3 of the electrode assembly 110 where the number of layers of the truncated piece decreases as it approaches the outer periphery. Preferably, the region b1 with a uniform number of layers can be set as the welding target area.

[0689] In the bent surface region F, the preferred numerical ranges of the ratio a2 / c of ​​the height-variable interval a2 to the radius region c containing the segment, the ratio b1 / c of ​​the uniform stacking interval b1 to the radius region c containing the segment, and the ratio of the area of ​​the bent surface region F to the area of ​​the uniform stacking interval b1 have already been described, so repeated descriptions are omitted.

[0690] The first current collector 144 can be soldered to the bent surface region F of the first uncoated portion 146a, and the second current collector 145 can be soldered to the bent surface region F of the second uncoated portion 146b.

[0691] The overlap relationship between the uniform stacking interval b1 and the reduced stacking interval b2 and the welding area W, the outer diameter of the first current collector 144 and the second current collector 176, and the configuration of the first part B1 not blocking the core diameter of more than 10% are substantially the same as the above contents.

[0692] The structures of the uncoated portions 146a and 146b can be modified to conform to the structures described in the above embodiments (various modifications). Furthermore, it is not limited to applying existing uncoated portion structures to either side of the uncoated portions 146a and 146b.

[0693] In the above-described embodiments (various modifications), the first current collector 144 and the second current collector 176 included in the cylindrical batteries 170, 180, 200, and 220, including terminal 172, can have the following characteristics: Figure 26 as well as Figure 27 The improved structure is shown.

[0694] The improved structure of the first current collector 144 and the second current collector 176 can help reduce the resistance of the cylindrical battery, improve vibration resistance, and increase energy density. In particular, the first current collector 144 and the second current collector 176 are more efficient than when used in large cylindrical batteries with a diameter-to-height ratio greater than 0.4.

[0695] Figure 26 This is a top top view showing the structure of the first current collector 144 according to an embodiment of the present invention.

[0696] Simultaneously refer to Figure 23and Figure 26 The first current collector 144 may include a contour portion 144a, a first uncoated portion joining portion 144b, and a terminal joining portion 144c. The contour portion 144a is disposed on the upper part of the electrode assembly 110. The contour portion 144a may have a free space S formed therein. open The approximate rim shape is shown in the accompanying drawings. Only the case where the outline portion 144a has a generally circular rim shape is shown, but the invention is not limited to this. Unlike the shape shown in the drawings, the outline portion 144a may also have a generally quadrilateral rim shape, a hexagonal rim shape, an octagonal rim shape, or other rim shapes. The number of outline portions 144a may be increased to two or more. In this case, the inner side of the outline portion 144a may include another outline portion of the rim shape.

[0697] In order to ensure the welding area for bonding with the flat portion 172c formed on the bottom surface of the terminal 172, the terminal bonding portion 144c may have the same or larger diameter as the flat portion 172c formed on the bottom surface of the terminal 172.

[0698] The first uncoated portion 144b extends inward from the outline portion 144a and is welded to the uncoated portion 146a. The terminal portion 144c is separate from the first uncoated portion 144b and is located inside the outline portion 144a. The terminal portion 144c can be welded to the terminal 172. The terminal portion 144c can be located, for example, approximately at the center of the inner space (sopen) surrounded by the outline portion 144a. The terminal portion 144c can be provided at a position corresponding to the hole formed in the core portion C of the electrode assembly 110. The terminal portion 144c can be configured to cover the hole formed in the core portion C of the electrode assembly 110 to prevent the hole formed in the core portion C of the electrode assembly 110 from being exposed on the outside of the terminal portion 144c. For this purpose, the terminal portion 144c can have a larger diameter or width than the hole formed in the core portion C of the electrode assembly 110.

[0699] The first uncoated portion joint 144b and the terminal joint 144c are not directly connected, but are configured to be separate from each other, and can be indirectly connected through the contour portion 144a. Thus, the first current collector 144 has a structure in which the first uncoated portion joint 144b and the terminal joint 144c are not directly connected but connected through the contour portion 144a, thereby dispersing the impact applied to the joint between the first uncoated portion joint 144b and the first uncoated portion 146a and the joint between the terminal joint 144c and the terminal 172 in the event of impact and / or vibration of the cylindrical battery 200. Only the case where there are four first uncoated portion joints 144b is shown in the accompanying drawings, but the present invention is not limited to this. Considering the manufacturing difficulty based on shape complexity, resistance, and the inner space (sopen) of the contour portion 144a considering electrolyte impregnation, the number of the first uncoated portion joints 144b can be determined to be various numbers.

[0700] The first current collector 144 may further include a bridging portion 144d extending inward from the profile portion 144a and connecting to the terminal connection portion 144c. The bridging portion 144d may be formed such that at least a portion thereof has a smaller cross-sectional area than both the first uncoated connection portion 144b and the profile portion 144a. For example, the bridging portion 144d may be formed such that at least a portion thereof has a smaller width and / or thickness than the first uncoated connection portion 144b. In this case, the resistance of the bridging portion 144d increases. As a result, when current flows through the bridging portion 144d, the relatively large resistance causes overcurrent heating and erosion in a portion of the bridging portion 144d. This irreversibly interrupts the overcurrent. Considering this overcurrent interruption function, the cross-sectional area of ​​the bridging portion 144d can be adjusted to an appropriate level.

[0701] The aforementioned bridging portion 144d may have a tapered portion 144e whose width gradually narrows as it approaches the terminal joint portion 144c from the inner side of the contour portion 144a. With the tapered portion 144e provided, the rigidity of the component at the connection between the bridging portion 144d and the contour portion 144a can be improved. With the tapered portion 144e provided, during the manufacturing process of the cylindrical battery 200, for example, a conveying device and / or an operator can hold the tapered portion 144e, thereby enabling simple and safe transport of the first current collector 144 and / or the assembly of the first current collector 144 and the electrode assembly 110. That is, with the tapered portion 144e provided, product defects that may occur when handling portions such as the first uncoated portion joint 144b and the terminal joint portion 144c that are welded to other components can be prevented.

[0702] Multiple first uncoated portion joints 144b may be provided. These multiple first uncoated portion joints 144b may be arranged at equal intervals along the extension direction of the contour portion 144a. The extension length of each of the multiple first uncoated portion joints 144b may be approximately the same. The first uncoated portion joints 144b may be joined to the bent surface region F of the uncoated portion 146a by laser welding. Welding may be replaced by ultrasonic welding, spot welding, etc.

[0703] The weld pattern 144f formed by welding between the first uncoated portion joint 144b and the bent surface region F can have a structure extending in the radial direction of the electrode assembly 110. The weld pattern 144f can be an arrangement of line patterns or dot patterns.

[0704] The aforementioned welding pattern 144f corresponds to the welding area. Therefore, preferably, the welding pattern 144f overlaps with the uniform layer number interval b1 of the bent surface region F by more than 50%. The welding pattern 144f that does not overlap with the uniform layer number interval b1 may overlap with the layer number reduction interval b2. More preferably, the welding pattern 144f as a whole may overlap with the uniform layer number interval b1 of the bent surface region F. Preferably, in the bent surface region F located below the point where the welding pattern 144f is formed, the layer number of the segments of the uniform layer number interval b1 and the optionally reduced layer number interval b2 is 10 or more.

[0705] The terminal joint 144c can be configured to be surrounded by a plurality of the aforementioned first uncoated joints 144b. The terminal joint 144c can be joined to the flat portion 172c of the terminal 172 by welding. The bridging portion 144d can be located between a pair of adjacent first uncoated joints 144b. In this case, the distance from the bridging portion 144d along the extension direction of the contour portion 144a to any one of the pair of first uncoated joints 144b can be approximately the same as the distance from the bridging portion 144d along the extension direction of the contour portion 144a to the remaining one of the pair of first uncoated joints 144b. The cross-sectional area of ​​each of the plurality of first uncoated joints 144b can be formed to be approximately the same. The width and thickness of each of the plurality of first uncoated joints 144b can be formed to be approximately the same.

[0706] Although not shown, multiple bridging portions 144d may be provided. Each of the multiple bridging portions 144d may be configured between a pair of adjacent first uncoated portion joints 144b. The multiple bridging portions 144d may be configured at approximately the same intervals along the extending direction of the profile portion 144a. The distance from each of the multiple bridging portions 144d to any one of the pairs of adjacent first uncoated portion joints 144b along the extending direction of the profile portion 144a may be approximately the same as the distance to the remaining first uncoated portion joint 144b.

[0707] As described above, when multiple first uncoated portion joints 144b and / or bridging portions 144d are provided, if the distance between the multiple first uncoated portion joints 144b and / or the distance between the multiple bridging portions 144d and / or the distance between the first uncoated portion joints 144b and the bridging portions 144d is formed to a certain extent, the flow of current from the first uncoated portion joints 144b to the bridging portions 144d or from the bridging portions 144d to the first uncoated portion joints 144b can be smoothly formed.

[0708] The bridging portion 144d may include a recessed portion N formed by locally reducing the cross-sectional area of ​​the bridging portion 144d. The cross-sectional area of ​​the recessed portion N can be adjusted, for example, by locally reducing the width and / or thickness of the bridging portion 144d. With the recessed portion N provided, the resistance in the region where the recessed portion N is formed increases, thereby allowing for rapid current interruption in the event of an overcurrent.

[0709] To prevent impurities generated during breakage from flowing into the electrode assembly 110, the grooved portion N is preferably provided in the region of the electrode assembly 110 corresponding to the uniform layer number range. This is because in this region, the layer number of the multiple segments of the uncoated portion 146a is maintained at its highest, thereby allowing the overlapping segments to function as a mask.

[0710] The grooved portion N can be wrapped with insulating tape. In this way, the heat generated in the grooved portion N will not dissipate to the outside, so when the overcurrent flows through the bridging portion 144d, the grooved portion N can be broken more quickly.

[0711] Figure 27 This is a top top view showing the structure of the second current collector 176 according to an embodiment of the present invention.

[0712] Simultaneously refer to Figure 23 and Figure 27The second current collector 176 is disposed at the lower part of the electrode assembly 110. Furthermore, the second current collector 176 can be configured to electrically connect the uncoated portion 146b of the electrode assembly 110 and the battery casing 171. The second current collector 176 is made of a conductive metal material and is electrically connected to the bent surface region F of the uncoated portion 146b. The second current collector 176 is also electrically connected to the battery casing 171. The second current collector 176 can be fixed by having its edge portion sandwiched between the inner side surface of the battery casing 171 and the first pad 178b. Specifically, the edge portion of the second current collector 176 can be sandwiched between the lower surface of the rolled edge portion 180 of the battery casing 171 and the first pad 178b. It should be noted that the present invention is not limited to this; alternatively, the edge portion of the second current collector 176 can also be welded to the inner wall surface of the battery casing 171 in the area where the rolled edge portion 180 is not formed.

[0713] The second current collector 176 may include a support portion 176a disposed at the lower part of the electrode assembly 110, a second uncoated portion joint portion 176b extending from the support portion 176a substantially along the radial direction of the electrode assembly 110 and joined to the bent surface region F of the uncoated portion 146b, and a housing joint portion 176c extending from the support portion 176a substantially along an inclined direction based on the radial direction of the electrode assembly 110 toward the inner side of the battery casing 171 and joined to the inner side. The second uncoated portion joint portion 176b and the housing joint portion 176c are indirectly connected through the support portion 176a and are not directly connected to each other. Therefore, when an external impact is applied to the cylindrical battery 200 of the present invention, the possibility of damage to the joint portion of the second current collector 176 with the electrode assembly 110 and the joint portion of the second current collector 176 with the battery casing 171 can be minimized. It should be noted that the second current collector 176 of the present invention is not limited to a structure in which the second uncoated portion joint 176b and the housing joint 176c are indirectly connected. For example, the second current collector 176 may also have a structure without a support portion 176a that indirectly connects the second uncoated portion joint 176b and the housing joint 176c, and / or a structure in which the uncoated portion 176b and the housing joint 176c are directly connected to each other.

[0714] The aforementioned support portion 176a and the second uncoated portion joint portion 176b are disposed at the lower part of the electrode assembly 110. The aforementioned second uncoated portion joint portion 176b is joined to the bent surface region F of the uncoated portion 146b. In addition to the aforementioned second uncoated portion joint portion 176b, the aforementioned support portion 176a may also be joined to the uncoated portion 146b. The aforementioned second uncoated portion joint portion 176b and the bent surface region F of the uncoated portion 146b can be joined by laser welding. Welding can be replaced by ultrasonic welding, spot welding, etc. When the battery casing 171 has a rolled edge portion 180, the aforementioned support portion 176a and the second uncoated portion joint portion 176b are located above the rolled edge portion 180.

[0715] The aforementioned support portion 176a has a current collector hole 176d formed at a position corresponding to the hole formed in the core portion C of the electrode assembly 110. The core portion C of the electrode assembly 110 and the current collector hole 176d, which are interconnected, can function as a welding rod for welding between the terminal 172 and the terminal joint portion 144c of the first current collector 144, or as a channel for irradiating a laser beam.

[0716] The aforementioned current collector hole 176d can have a radius r relative to the hole formed in the core C of the electrode assembly 110. c 0.5r c The radius mentioned above. The radius of the current collector hole 176d is 0.5r. c Up to 1.0r c In the event of venting in the cylindrical battery 200, this prevents the separation membrane or the winding structure of multiple electrodes near the core C of the electrode assembly 110 from being pushed outwards by the venting pressure. This is done when the radius of the current collector hole 176d is greater than 1.0r. c At that time, because the core C is open to the maximum extent, it is easy to inject electrolyte during the electrolyte injection process.

[0717] When the aforementioned second uncoated portion joint 176b is provided with multiple openings, the multiple second uncoated portion joints 176b can have a shape that extends generally radially toward the sidewall of the battery casing 171 from the support portion 176a of the second current collector 176. Each of the aforementioned multiple second uncoated portion joints 176b can be positioned separately from each other along the periphery of the support portion 176a.

[0718] Multiple housing joints 176c may be provided. In this case, the multiple housing joints 176c may have a shape that extends generally radially from the center of the second current collector 176 toward the sidewall of the battery casing 171. This allows for electrical connection between the second current collector 176 and the battery casing 171 at multiple points. By achieving this connection at multiple points, the connection area is maximized and the resistance is minimized. Each of the multiple housing joints 176c may be positioned separately from each other along the periphery of the support portion 176a. At least one housing joint 176c may be located between adjacent second uncoated portion joints 176b. The multiple housing joints 176c may be joined to, for example, a rolled edge portion 180 on the inner surface of the battery casing 171. In particular, the multiple housing joints 176c may be joined to the lower surface of the rolled edge portion 180 by laser welding. Welding may be replaced by ultrasonic welding, spot welding, etc. By welding multiple housing joints 176c onto the rolled edge 180, the current path is dispersed radially, limiting the resistance of the cylindrical battery 200 to approximately 4 milliohms (mΩ) or less. Furthermore, the shape of the rolled edge 180, with its lower surface extending approximately parallel to the upper surface of the battery casing 171 (i.e., perpendicular to the sidewall of the battery casing 171) and the housing joints 176c extending in the same direction (radial and circumferential), allows the housing joints 176c to stably contact the rolled edge 180. Moreover, by ensuring stable contact between the housing joints 176c and the flat portion of the rolled edge 180, welding between the two components can be smoothly achieved, thereby increasing the bonding strength between the two components and minimizing the increase in resistance at the joint.

[0719] The aforementioned housing joint 176c may include a contact portion 176e attached to the inner side of the battery housing 171 and a connecting portion 176f connecting the support portion 176a and the contact portion 176e.

[0720] The aforementioned contact portion 176e is bonded to the inner side of the battery casing 171. When the battery casing 171 has a rolled edge portion 180, as described above, the contact portion 176e can be bonded to the rolled edge portion 180. More specifically, the contact portion 176e can be electrically bonded to a flat portion formed on the lower surface of the rolled edge portion 180 of the battery casing 171, and can be sandwiched between the lower surface of the rolled edge portion 180 and the first pad 178b. In this case, to achieve stable contact and bonding, the contact portion 176e can have a shape that extends a predetermined length from the rolled edge portion 180 along the circumferential direction of the battery casing 171.

[0721] The connecting portion 176f can be bent into an obtuse angle. The bending point can be the upper part of the midpoint of the connecting portion 176f. If the connecting portion 176f is bent, the contact portion 176e can be stably supported by the flat surface of the rolled edge portion 180. The connecting portion 176f is divided into a lower part and an upper part based on the bending point, and the length of the lower part can be longer than that of the upper part. Furthermore, the inclination angle of the lower part based on the surface of the support portion 176a can be larger than that of the upper part. If the connecting portion 176f is bent, the pressure (force) applied in the vertical direction of the battery casing 171 can be buffered. As an example, when pressure is transmitted to the contact portion 176e during the sizing process of the battery casing 171, causing the contact portion 176e to move vertically toward the support portion 176b, the bending point of the connecting portion 176f moves upward, thereby deforming the shape of the connecting portion 176, thereby buffering the stress pressure.

[0722] On the other hand, preferably, the maximum distance from the center of the second current collector 176 to the end of the second uncoated portion joint 176b along the radial direction of the electrode assembly 110 is formed to be the same as or smaller than the inner diameter of the battery casing 171 in the region where the rolled edge portion 180 is formed, i.e., the minimum inner diameter of the battery casing 171. This is to prevent the end of the second uncoated portion joint 176b from pressing against the edge of the electrode assembly 110 during the precision pressing process of compressing the battery casing 171 in the height direction.

[0723] The second uncoated portion joint 176b includes a hole 176g. The hole 176g can be used as a channel for electrolyte movement. The weld pattern 176h formed by welding the second uncoated portion joint 176b to the bent surface region F can have a structure extending in the radial direction of the electrode assembly 110. The weld pattern 176h can be an arrangement of line patterns or dot patterns.

[0724] The aforementioned welding pattern 176h corresponds to the welding area. Therefore, preferably, the welding pattern 176h overlaps by more than 50% with the uniform layer number interval b1 of the bent surface region F located below the electrode assembly 110. The welding pattern 176h that does not overlap with the uniform layer number interval b1 may overlap with the layer number reduction interval b2. More preferably, the welding pattern 176h as a whole may overlap with the uniform layer number interval b1 of the bent surface region F. Preferably, in the bent surface region F located above the point where the welding pattern 176h is formed, the layer number of the segments of the uniform layer number interval b1 and, optionally, the layer number reduction interval b2 is 10 or more.

[0725] The outer diameters of the first current collector 144 and the second current collector 176 described above are different from each other. The outer diameter is the outer edge diameter of the contact area between the bent surface region F and the current collector. The outer diameter is defined as the maximum value of the distances between the two points where the straight line passing through the center of the core C of the electrode assembly intersects the edge of the contact area. The second current collector 176 is located inside the rolled edge 180, so its outer diameter is smaller than that of the first current collector 144. Furthermore, the length of the weld pattern 144f of the first current collector 144 is longer than the length of the weld pattern 176h of the second current collector 176. Preferably, with the center of the core C as a reference, the weld patterns 144f and 176h can extend outward from substantially the same point.

[0726] The cylindrical batteries 170, 180, 200, and 220 according to embodiments of the present invention have the advantage of being able to make electrical connections at the top.

[0727] Figure 28 This is a top top view showing the electrical connection of multiple cylindrical batteries 200. Figure 29 yes Figure 28 A magnified view of a portion of the image. The cylindrical battery 200 can be replaced by cylindrical batteries 170, 180, and 220 with other structures.

[0728] Reference Figure 28 as well as Figure 29 Multiple cylindrical batteries 200 can be connected in series and in parallel at the top of the cylindrical batteries 200 via a bus 210. The number of cylindrical batteries 200 can be increased depending on the capacity of the battery pack.

[0729] In each cylindrical battery 200, terminal 172 is anode, and the flat surface 171a around terminal 172 of battery casing 171 can be cathode. Of course, the opposite is also possible.

[0730] Preferably, the plurality of cylindrical batteries 200 can be configured as multiple columns and rows. Columns are arranged vertically in the figures, and rows are arranged horizontally in the figures. Furthermore, to maximize space efficiency, the plurality of cylindrical batteries 200 can be configured as a closest packing structure. The closest packing structure is formed when the centers of the terminals 172 exposed to the outside of the battery casing 171 are connected to each other, forming an equilateral triangle shape. Preferably, the bus 210 connects the plurality of cylindrical batteries 200 arranged in the same column in parallel, and connects the plurality of cylindrical batteries 200 arranged in two adjacent columns in series.

[0731] Preferably, for series and parallel connections, the bus 210 may include a main body 211, a plurality of first bus terminals 212 and a plurality of second bus terminals 213.

[0732] The main body 211 can extend along a column of cylindrical batteries 200 between adjacent terminals 172. Alternatively, the main body 211 can extend along a column of cylindrical batteries 200, and the main body 211 can be bent regularly in a zigzag pattern.

[0733] Multiple first bus terminals 212 can extend to one side of the main body 211 and be electrically connected to terminals 172 of the cylindrical battery 200 located on one side. The electrical connection between the first bus terminals 212 and terminals 172 can be achieved by laser welding, ultrasonic welding, or the like.

[0734] Multiple second bus terminals 213 can extend to the other side of the main body 211 and be electrically connected to a flat surface 171a surrounding a terminal 172 located on the other side. The electrical connection between the second bus terminals 213 and the flat surface 171a can be achieved by laser welding, ultrasonic welding, or the like.

[0735] Preferably, the main body 211, the plurality of first bus terminals 212, and the plurality of second bus terminals 213 can be constructed from a single conductive metal plate. The metal plate can be, for example, an aluminum plate or a copper plate, but the invention is not limited thereto. In a variation, the main body 211, the plurality of first bus terminals 212, and the second bus terminals 213 can be manufactured as separate blocks and then joined together by welding or the like.

[0736] The cylindrical battery 200 of the present invention described above has a structure in which resistance is minimized by increasing the welding area based on the bent surface region F, multiplexing the current path using the second current collector 176, and minimizing the current path length. The AC resistance of the cylindrical battery 200, measured by a resistance meter between the anode and cathode (i.e., between the terminal 172 and its surrounding flat surface 171a), can be approximately 4 milliohms (mΩ) or less, suitable for fast charging.

[0737] According to the cylindrical battery 200 of the present invention, the terminal 172 having an anode and the flat surface 171a having a cathode are located in the same direction, so the electrical connection of multiple cylindrical batteries 200 can be easily realized by using the bus 210.

[0738] Furthermore, the cylindrical battery 200 has a large area of ​​terminal 172 and its surrounding flat surface 171a, thus ensuring sufficient bonding area of ​​bus 210 and significantly reducing the resistance of the battery pack including the cylindrical battery 200.

[0739] Furthermore, electrical wiring can be carried out on the upper part of the cylindrical battery 200, thus having the advantage of maximizing the energy density per unit volume of the battery module / pack.

[0740] The cylindrical battery according to the above embodiments (variables) can be used to manufacture battery packs.

[0741] Figure 30 This is a diagram that briefly illustrates the configuration of a battery pack according to an embodiment of the present invention.

[0742] Reference Figure 30 According to an embodiment of the present invention, the battery pack 300 includes an assembly of cylindrical batteries 301 electrically connected to each other and a housing 302 for housing the assembly. The cylindrical batteries 301 can be any one of the batteries according to the above-described embodiments (variations). In the accompanying drawings, for ease of illustration, components such as buses, cooling units, and external terminals for electrically connecting the multiple cylindrical batteries 301 are omitted.

[0743] The battery pack 300 can be installed in a vehicle. For example, the vehicle can be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. Vehicles can be four-wheeled or two-wheeled.

[0744] Figure 31 It is used to illustrate including Figure 30 A picture of a car with a 300 battery pack.

[0745] Reference Figure 31 A vehicle V according to an embodiment of the present invention includes a battery pack 300 according to an embodiment of the present invention. The vehicle V receives power from the battery pack 300 according to an embodiment of the present invention for operation.

[0746] According to the present invention, by using the uncoated portions protruding from the upper and lower parts of the electrode assembly as electrode tabs themselves, it is possible to reduce the internal resistance of the battery and increase the energy density.

[0747] According to another aspect of the invention, the uncoated portion structure of the electrode assembly is improved, thereby avoiding interference between the inner surface of the electrode assembly and the battery casing during the formation of the rolled edge portion of the battery casing, thereby preventing short circuits inside the cylindrical battery caused by local deformation of the electrode assembly.

[0748] According to another aspect of the present invention, the structure of the uncoated portion of the electrode assembly is improved, thereby preventing the uncoated portion from tearing when bent, and the number of layers of the uncoated portion is sufficiently increased, thereby improving the welding strength of the current collector.

[0749] According to another aspect of the invention, a slit structure is applied to the uncoated portion of the electrode, and the dimensions (width, height, and spacing) of the slit are optimized, thereby significantly increasing the number of slit stacks in the area used as the welding target area, thereby improving the physical properties of the area used for welding current collectors.

[0750] According to another aspect of the invention, by applying a structure in which the current collector is welded over a large area in the bent surface region formed by bending multiple segments, it is possible to provide an electrode assembly that increases energy density and reduces resistance.

[0751] According to another aspect of the invention, it is possible to provide a cylindrical battery whose design is improved to enable electrical wiring to be performed from the top.

[0752] According to another aspect of the present invention, the structure of the uncoated portion adjacent to the core of the electrode assembly is improved, preventing the uncoated portion from blocking the cavity in the core of the electrode assembly when bent, and enabling simple electrolyte injection and welding of the battery casing (or rivet terminal) to the current collector.

[0753] According to another aspect of the present invention, it is possible to provide a cylindrical battery having a structure with low internal resistance, preventing internal short circuits, and improving the welding strength of the current collector and the uncoated portion, a battery pack including the cylindrical battery, and an automobile.

[0754] In particular, the present invention can provide a cylindrical battery with a diameter-to-height ratio of 0.4 or higher and a resistance of 4 mΩ or lower, as well as a battery pack including the cylindrical battery and an automobile.

[0755] As described above, although the present invention has been illustrated with limited embodiments and drawings, the present invention is not limited thereto. Those skilled in the art to which this invention pertains should be able to make various modifications and variations within the technical concept and scope equivalent to the claims.

Claims

1. An electrode assembly comprising a first electrode, a second electrode, and a separation membrane sandwiched therebetween, which are wound around a winding shaft to define a core and an outer peripheral surface, characterized in that, The aforementioned first electrode, along the winding direction, includes a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. At least a portion of the aforementioned first uncoated portion is defined in itself as an electrode tab. The first uncoated portion includes a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer peripheral surface of the electrode assembly, and a third portion between the first portion and the second portion. Along the winding axis, the first portion or the second portion has a lower height than the third portion. in, At least a portion of the third part described above is divided into multiple segments that can be bent individually. Among them, a cutting groove is sandwiched between adjacent segments along the aforementioned winding direction. An insulating coating is formed in the region of the uncoated portion within the area separating the bottom of the cut-off groove from the active material layer, and at the boundary between the active material layer and the uncoated portion. The bottom of the cut-off groove and the insulating coating are separate from each other.

2. The electrode assembly according to claim 1, characterized in that, The third part described above is defined as the electrode tab in a state of bending along the radial direction of the electrode assembly.

3. The electrode assembly according to claim 1, characterized in that, The second and third parts mentioned above are defined as electrode tabs in a state of bending along the radial direction of the electrode assembly.

4. The electrode assembly according to claim 1, characterized in that, Each of the multiple segments has the shape of a geometric figure formed by connecting more than one straight line, more than one curve, or a combination thereof.

5. The electrode assembly according to claim 4, characterized in that, The bottom width of each of the multiple slices is greater than the top width.

6. The electrode assembly according to claim 4, characterized in that, The bottom width of each of the multiple slices is the same as the top width.

7. The electrode assembly according to claim 4, characterized in that, The width of each of the multiple segments decreases as it approaches the top from the bottom.

8. The electrode assembly according to claim 4, characterized in that, The width of each of the multiple slices first decreases and then increases as it approaches the top from the bottom.

9. The electrode assembly according to claim 4, characterized in that, The width of each of the multiple slices first increases and then decreases as it approaches the top from the bottom.

10. The electrode assembly according to claim 4, characterized in that, The width of each of the multiple segments first increases as it approaches the top from the bottom and then remains at a certain width.

11. The electrode assembly according to claim 4, characterized in that, The width of each of the multiple segments decreases as it approaches the top from the bottom and then remains at a certain width.

12. The electrode assembly according to claim 4, characterized in that, Along a direction parallel to the aforementioned winding direction, the lower interior angles of multiple slices are increased individually or in groups.

13. The electrode assembly according to claim 12, characterized in that, Along a direction parallel to the aforementioned winding direction, the lower interior angles of multiple slices are increased individually or in groups, ranging from 60 degrees to 85 degrees.

14. The electrode assembly according to claim 1, characterized in that, Each of the aforementioned segments has a geometric shape in which the width decreases as it approaches the top. The lower interior angle θ of the segment located on the winding loop of radius r centered on the core of the aforementioned electrode assembly belongs to the range of angles defined by the following mathematical formula: ， Where D is the width of the slice in the winding direction; r is the radius of the winding loop containing the slice; H is the height of the slice; and p is the spacing between the slices.

15. The electrode assembly according to claim 4, characterized in that, Each of the multiple slices has a side composed of a straight line, a curve, or a combination thereof.

16. The electrode assembly according to claim 4, characterized in that, Each of the multiple slices has its side bulging outwards or inwards.

17. The electrode assembly according to claim 4, characterized in that, Each of the multiple segments has a chamfered corner at its upper part.

18. The electrode assembly according to claim 1, characterized in that, The lower part of the cut-off groove includes: the bottom; and chamfered portions connecting the two ends of the bottom and the sides of the segments located on both sides of the cut-off groove.

19. The electrode assembly according to claim 18, characterized in that, The radius of curvature of the chamfered portion is greater than 0 and less than 0.1 mm.

20. The electrode assembly according to claim 18, characterized in that, The radius of curvature of the chamfered portion is 0.01 mm to 0.05 mm.

21. The electrode assembly according to claim 18, characterized in that, The bottom is flat.

22. The electrode assembly according to claim 18, characterized in that, The separation interval, defined as the distance between two points where the lines extending from the sides of the two segments located on both sides of the cut-off groove and the line extending from the bottom of the cut-off groove intersect, is 0.05 mm to 1.00 mm.

23. The electrode assembly according to claim 18, characterized in that, The aforementioned multiple segments are made of aluminum foil, and the separation interval, defined by the distance between the two points where the lines extending from the sides of the two segments located on both sides of the aforementioned cutting groove intersect and the line extending from the lower end of the aforementioned cutting groove, is 0.5 mm to 1.00 mm.

24. The electrode assembly according to claim 18, characterized in that, The bottom of the aforementioned cut-off groove is separated from the aforementioned active material layer by a certain distance.

25. The electrode assembly according to claim 24, characterized in that, The separation distance between the bottom of the cut-off groove and the active material layer is 0.2 mm to 4 mm.

26. The electrode assembly according to claim 18, characterized in that, The aforementioned multiple segments are bent along the radial direction of the aforementioned electrode assembly within a 0 to 1 mm range above the bottom of the cut-off groove.

27. The electrode assembly according to claim 1, characterized in that, With the core center of the aforementioned electrode assembly as a reference, the circumferential angle of the arc formed by the lower end of each of the aforementioned multiple segments is less than 30 degrees.

28. The electrode assembly according to claim 1, characterized in that, When the radius of the winding loop containing the slice, with the core center of the aforementioned electrode assembly as the reference, is defined as r, and the width of the slice in the winding direction is defined as D(r), D(r) satisfies the following mathematical expression: 1 mm ≤ D (r) ≤ (2 π (360°) 45°.

29. The electrode assembly according to claim 28, characterized in that, As the radius r of the winding loop containing the segment with reference to the core center of the aforementioned electrode assembly increases, the width D(r) of the winding direction of each of the plurality of segments gradually or in stages increases or decreases.

30. The electrode assembly according to claim 28, characterized in that, As the radius r of the winding loop containing the segment with reference to the core center of the aforementioned electrode assembly increases, the width D(r) of the winding direction of each of the plurality of segments first gradually or in stages increases and then gradually or in stages decreases or the opposite occurs.

31. The electrode assembly according to claim 27, characterized in that, With the core center of the aforementioned electrode assembly as a reference, the circumferential angles of each of the aforementioned multiple segments are substantially the same.

32. The electrode assembly according to claim 27, characterized in that, Along a direction parallel to the winding direction of the aforementioned electrode assembly, the widths of the plurality of segments in the winding direction are substantially the same or increase at different ratios.

33. The electrode assembly according to claim 1, characterized in that, As the radius r of the winding loop containing the segment with reference to the core center of the aforementioned electrode assembly increases, the width of each of the aforementioned segments gradually or in stages increases within the range of 1 mm to 11 mm.

34. The electrode assembly according to claim 1, characterized in that, Along a direction parallel to the aforementioned winding direction, the height of at least a portion of the third part in the winding axis direction gradually or in stages changes.

35. The electrode assembly according to claim 34, characterized in that, Along a direction parallel to the aforementioned winding direction, the height of at least a portion of the second and third portions in the winding axis direction gradually or in stages increases.

36. The electrode assembly according to claim 34, characterized in that, The third part is divided into multiple regions of different heights along a direction parallel to the winding direction, and the height of the uncoated portion in the multiple regions increases in stages along a direction parallel to the winding direction.

37. The electrode assembly according to claim 1, characterized in that, The first uncoated portion includes a section whose height varies in stages along a direction parallel to the winding direction, from a first height h1 to a (N-1)th height h. N-1 The height variable range and uniformly maintaining the Nth height h N The height is uniformly distributed within a range, where N is the height index and is a natural number greater than 2, h N Greater than h N-1 .

38. The electrode assembly according to claim 37, characterized in that, The N mentioned above is between 2 and 30.

39. The electrode assembly according to claim 37, characterized in that, With height h k The number of slices is multiple, with a height h k Multiple segments are configured on one or more winding loops, where k is a natural number from 1 to N.

40. The electrode assembly according to claim 37, characterized in that, In the case of containing a height h k The starting radius of the winding loop of the cut piece is defined as r. k At that time, more than 90% of the diameter of the core of the aforementioned electrode assembly is not located in the aforementioned r k The folded portion of the slice is occluded, where k is a natural number from 1 to N.

41. The electrode assembly according to claim 37, characterized in that, In the case of containing a height h k Let the starting radius of the winding loop of the cut piece be r. k Let the radius of the core be r. c At that time, the height h of the slice k Satisfy the following mathematical expression: 2mm≤h k ≤r k -a r c , Where k is a natural number from 1 to N, and α is from 0.90 to 1.

42. The electrode assembly according to claim 1, characterized in that, Based on the cross section along the winding axis, the electrode assembly sequentially includes a section without cut pieces, a height-variable section with variable cut piece height, and a height-uniform section with uniform cut piece height. The plurality of cut pieces are arranged in the height-variable section and the height-uniform section, and are bent along the radial direction of the electrode assembly to form a bent surface area.

43. The electrode assembly according to claim 42, characterized in that, The first part mentioned above was not divided into multiple segments, and the omitted intervals of the segments mentioned above correspond to the first part mentioned above.

44. The electrode assembly according to claim 42, characterized in that, The aforementioned variable height range and the aforementioned uniform height range correspond to the third part mentioned above.

45. The electrode assembly according to claim 42, characterized in that, The second part is divided into multiple segments that can be bent individually, and the variable height range and the uniform height range correspond to the second part and the third part, respectively.

46. ​​The electrode assembly according to claim 42, characterized in that, Within the aforementioned variable height range and the aforementioned uniform height range, the maximum height h of the sectional slice is... max Satisfy the following mathematical expression: h max ≤W foil –W scrap，min W margin，min –W gap , Among them, W foil It is the width of the current collector foil before the stencil is formed; W scrap，min It is the width equivalent to the minimum chip breaking allowance when cutting the current collector foil to form the slit; W margin，min It is the width corresponding to the minimum serpentine allowance of the separation membrane; W gap It is equivalent to the width of the insulating gap between the end of the second electrode, which is opposite to the first electrode and separated by the separation membrane, and the end of the separation membrane.

47. The electrode assembly according to claim 46, characterized in that, When the first electrode is the anode, the insulation gap W gap It ranges from 0.2mm to 6mm.

48. The electrode assembly according to claim 46, characterized in that, When the first electrode is a cathode, the insulation gap W gap It ranges from 0.1mm to 2mm.

49. The electrode assembly according to claim 46, characterized in that, Minimum chip breaking allowance W scrap，min It ranges from 1.5mm to 8mm.

50. The electrode assembly according to claim 46, characterized in that, The minimum serpentine margin W of the above separation membrane margin，min It is 0 to 1 mm.

51. The electrode assembly according to claim 46, characterized in that, The minimum chip breaking allowance mentioned above is 0.

52. The electrode assembly according to claim 42, characterized in that, The height of the segments configured in the above-mentioned variable height range gradually or in stages increases within the range of 2mm to 10mm.

53. The electrode assembly according to claim 42, characterized in that, In the radial direction of the aforementioned electrode assembly, the ratio of the radial length of the omitted section of the aforementioned sectional section to the radius of the aforementioned electrode assembly excluding the aforementioned core is 10% to 40%.

54. The electrode assembly according to claim 42, characterized in that, In the radial direction of the aforementioned electrode assembly, the ratio of the radial length of the aforementioned height-variable range to the radial length corresponding to the aforementioned height-variable range and the aforementioned height-uniform range is 1% to 50%.

55. The electrode assembly according to claim 42, characterized in that, The ratio of the length of the electrode region corresponding to the omitted section of the above-mentioned sectional view to the overall length of the first electrode is 1% to 30%.

56. The electrode assembly according to claim 42, characterized in that, The ratio of the length of the electrode region corresponding to the aforementioned height-variable range to the overall length of the aforementioned first electrode is 1% to 40%.

57. The electrode assembly according to claim 42, characterized in that, The ratio of the length of the electrode region corresponding to the aforementioned height uniformity interval to the overall length of the aforementioned first electrode is 50% to 90%.

58. The electrode assembly according to claim 1, characterized in that, As the slices approach a direction parallel to the winding direction, at least one of the widths selected from the winding direction and the heights selected from the winding axis direction increases in stages or continuously.

59. The electrode assembly according to claim 1, characterized in that, As the slices approach a direction parallel to the winding direction, at least one of the widths selected from the winding direction and the heights selected from the winding axis direction first increases or continues in stages, then decreases or continues in stages, or vice versa.

60. The electrode assembly according to claim 1, characterized in that, As the multiple segments approach a direction parallel to the winding direction of the aforementioned electrode assembly, they form multiple segments groups, and the width in the winding direction and the height in the winding axis direction of the multiple segments belonging to the same segments group are substantially the same.

61. The electrode assembly according to claim 60, characterized in that, As the direction approaches parallel to the winding direction of the aforementioned electrode assembly, at least one of the width of the winding direction and the height of the winding axis of the multiple segments belonging to the same segment group increases in stages.

62. The electrode assembly according to claim 60, characterized in that, When the width of the winding direction of each of three consecutive and adjacent cut pieces parallel to the winding direction of the above-mentioned electrode assembly is set as W1, W2 and W3, it includes a combination of cut pieces that are smaller than W2 / W1 compared to W3 / W2.

63. The electrode assembly according to claim 1, characterized in that, The first part is not divided into multiple segments, and the first part is not bent along the radial direction of the electrode assembly.

64. The electrode assembly according to claim 1, characterized in that, The second part is not divided into multiple segments, and the second part is not bent along the radial direction of the electrode assembly.

65. The electrode assembly according to claim 18, characterized in that, The aforementioned insulating coating comprises a polymer resin and inorganic fillers dispersed in the aforementioned polymer resin.

66. The electrode assembly according to claim 18, characterized in that, The insulating coating is formed to cover the boundary portion between the active material layer and the first uncoated portion along the winding direction.

67. The electrode assembly according to claim 66, characterized in that, The insulating coating is formed to cover the boundary between the active material layer and the first uncoated portion with a width of 0.3 mm to 5 mm along the winding axis.

68. The electrode assembly according to claim 18, characterized in that, The end of the aforementioned insulating coating is located within a range of -2 mm to 2 mm along the winding axis, with the end of the aforementioned separating membrane as a reference.

69. The electrode assembly according to claim 68, characterized in that, The aforementioned insulating coating is exposed on the outside of the aforementioned separation membrane.

70. The electrode assembly according to claim 18, characterized in that, The lower end of the cut-off groove is separated from the insulating coating by a distance of 0.5 mm to 2 mm.

71. The electrode assembly according to claim 70, characterized in that, The end of the aforementioned insulating coating in the winding axis direction is located within the range of -2mm to +2mm, with the lower end of the aforementioned cut-off groove as a reference.

72. The electrode assembly according to claim 18, characterized in that, The second electrode includes a second active material portion coated with an active material layer along the winding direction, and the end of the second active material portion is located between the upper end and the lower end of the insulating coating in the winding axis direction.

73. The electrode assembly according to claim 1, characterized in that, The second part is divided into multiple segments that can be bent individually, and the electrode assembly includes a bending surface area formed when the multiple segments are bent along the radial direction of the electrode assembly.

74. The electrode assembly according to claim 73, characterized in that, Taking the core center of the aforementioned electrode assembly as a reference, when the number of segments intersecting with a virtual line parallel to the winding axis at any radius position in the aforementioned bent surface region is defined as the number of segments stacked at the corresponding radius position, the aforementioned bent surface region includes a uniform stacking interval where the number of segments stacked is uniform as it approaches the outer periphery, and a stacking reduction interval located outside the uniform stacking interval where the number of segments stacked decreases as it approaches the outer periphery.

75. The electrode assembly according to claim 74, characterized in that, With the core center of the aforementioned electrode assembly as a reference, the radial lengths of the uniform stacking interval and the decreasing stacking interval correspond to the radial lengths of the radial intervals containing the multiple winding loops of the aforementioned multiple slices.

76. The electrode assembly according to claim 74, characterized in that, The electrode assembly includes, in sequence along the radial direction, a section with no cut-out, a section with variable height of cut-out, and a section with uniform height of cut-out. Taking the core center of the electrode assembly as a reference, the starting radius of the section with uniform stacking corresponds to the starting radius of the section with variable height.

77. The electrode assembly according to claim 74, characterized in that, Within the aforementioned uniform range of stacking numbers, the stacking number of the above-mentioned sections is between 10 and 35.

78. The electrode assembly according to claim 74, characterized in that, The first electrode is the anode, and within the uniform stacking range, the stacking thickness of the sectional section is 100 μm to 875 μm.

79. The electrode assembly according to claim 74, characterized in that, The first electrode is a cathode, and within the uniform stacking range, the stacking thickness of the sectional section is 50 μm to 700 μm.

80. The electrode assembly according to claim 74, characterized in that, The ratio of the radial length of the uniform stacking interval to the radial length of the uniform stacking interval and the decreasing stacking interval is 30% to 85%.

81. The electrode assembly according to claim 74, characterized in that, Also includes: The current collector is welded to the aforementioned bent surface area. In the radial direction of the electrode assembly, the welding area of ​​the current collector overlaps with the uniform stacking interval by at least 50%.

82. The electrode assembly according to claim 81, characterized in that, In the radial direction of the aforementioned electrode assembly, the area in the welding region of the aforementioned current collector that does not overlap with the aforementioned uniform stacking interval overlaps with the aforementioned reduced stacking interval.

83. The electrode assembly according to claim 81, characterized in that, The edge of the current collector is welded to the bent surface region in such a way that it covers the end of the bent portion of the outermost segment in the radial direction of the electrode assembly.

84. The electrode assembly according to claim 81, characterized in that, The welding strength of the welding area of ​​the aforementioned current collector is 2 kgf / cm². 2 above.

85. The electrode assembly according to claim 81, characterized in that, The welding strength of the welding area of ​​the aforementioned current collector is 4 kgf / cm². 2 above.

86. The electrode assembly according to claim 1, characterized in that, The first uncoated portion is made of metal foil. The elongation of the aforementioned metal foil is 1.5% to 3.0%, and the tensile strength is 25 kgf / mm². 2 Up to 35 kgf / mm 2 .

87. The electrode assembly according to claim 86, characterized in that, The aforementioned metal foil is aluminum foil.

88. The electrode assembly according to claim 86, characterized in that, The bending length of the first electrode is less than 20 mm.

89. The electrode assembly according to claim 1, characterized in that, The ratio of the length of the short side parallel to the winding axis direction to the length of the long side parallel to the winding direction of the first active material portion is 1% to 4%.

90. The electrode assembly according to claim 1, characterized in that, The height of the second part mentioned above decreases in stages or gradually as it moves from the core side of the electrode assembly toward the outer periphery.

91. The electrode assembly according to claim 1, characterized in that, The second part is divided into multiple segments that can be bent individually. Compared with the segments included in the third part, the segments included in the second part have at least one greater width in the winding direction and height in the winding axis direction.

92. The electrode assembly according to claim 1, characterized in that, The third part mentioned above includes the section of the cut sheet that is not set along the winding direction of the electrode assembly.

93. The electrode assembly according to claim 92, characterized in that, The third part mentioned above includes multiple cutout intervals along a direction parallel to the winding direction.

94. The electrode assembly according to claim 93, characterized in that, The width of each of the above-mentioned multiple cutout intervals increases or decreases along a direction parallel to the above-mentioned winding direction.

95. The electrode assembly according to claim 92, characterized in that, The height of the uncoated portion of the omitted section of the above-mentioned cutaway is substantially the same as the height of the uncoated portion of the first part or the uncoated portion of the second part.

96. The electrode assembly according to claim 92, characterized in that, The aforementioned multiple segments are located within a pre-defined circumferential angle range based on the core center of the aforementioned electrode assembly.

97. The electrode assembly according to claim 92, characterized in that, The aforementioned multiple segments are located in two or more fan-shaped or polygonal regions arranged circumferentially with reference to the core center of the aforementioned electrode assembly.

98. The electrode assembly according to claim 97, characterized in that, The circumferential angle of the aforementioned sector is 20 degrees or more.

99. The electrode assembly according to claim 1, characterized in that, The second electrode, along the winding direction, includes a second active material portion coated with an active material layer and a second uncoated portion without an active material layer. At least a portion of the second uncoated portion is defined as an electrode tab. The second uncoated portion includes a section divided into multiple segments that can be bent individually. The multiple segments are bent along the radial direction of the electrode assembly to form a bent surface region.

100. An electrode assembly comprising a first electrode, a second electrode, and a separation membrane sandwiched therebetween, which are wound around a winding shaft to define a core and an outer peripheral surface, characterized in that... The aforementioned first electrode, along the winding direction, includes a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. The aforementioned first uncoated portion includes, from the core side of the aforementioned electrode assembly along its outer periphery, a region divided into multiple segments capable of being individually bent. The aforementioned multiple segments are bent along the radial direction of the aforementioned electrode assembly to form a bent surface region. The aforementioned bent surface region, along the radial direction, includes a uniform layer number interval where the number of layers of the aforementioned section is 10 or more, and a layer number decreasing interval adjacent to the aforementioned uniform layer number interval where the number of layers of the aforementioned section decreases as it moves away from the aforementioned uniform layer number interval. in, Cut-off grooves are sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

101. The electrode assembly according to claim 100, characterized in that, Along the radial direction of the electrode assembly, there are sequentially three sections: a section with no cut-out pieces, a section with variable height where the height of the cut-out pieces increases in stages, and a section with uniform height where the height of the cut-out pieces is uniform. With the core center of the electrode assembly as a reference, the starting radius of the section with uniform stacking corresponds to the starting radius of the section with variable height.

102. The electrode assembly according to claim 101, characterized in that, The first uncoated portion adjacent to the core is not divided into multiple segments, and the winding coil is arranged in the omitted segment section.

103. The electrode assembly according to claim 101, characterized in that, The ratio of the radial length of the uniform stacking interval to the radial length of the uniform stacking interval and the decreasing stacking interval is 30% to 85%.

104. The electrode assembly according to claim 101, characterized in that, The length of the electrode region corresponding to the omitted section of the above-mentioned cut is in the ratio of 1% to 30% to the overall length of the first electrode along the above-mentioned winding direction.

105. The electrode assembly according to claim 101, characterized in that, The ratio of the length of the electrode region corresponding to the aforementioned height variable range to the overall length of the aforementioned first electrode along the aforementioned winding direction is 1% to 40%.

106. The electrode assembly according to claim 101, characterized in that, The ratio of the length of the electrode region corresponding to the aforementioned height uniformity interval to the overall length of the aforementioned first electrode along the aforementioned winding direction is 50% to 90%.

107. The electrode assembly according to claim 100, characterized in that, In the interval divided into the aforementioned multiple segments, along a direction parallel to the aforementioned winding direction, at least one of the following is progressively increased: the width of the segment in the winding direction, the height in the winding axis direction, and the lower interior angle.

108. The electrode assembly according to claim 100, characterized in that, The height of the first uncoated portion region adjacent to the core side or outer peripheral side of the aforementioned electrode assembly is lower than the height of the aforementioned plurality of segments.

109. The electrode assembly according to claim 100, characterized in that, The aforementioned multiple segments are bent toward the core side of the aforementioned electrode assembly, and more than 90% of the diameter of the core of the aforementioned electrode assembly is not obscured by the bent portion of the segment positioned closest to the core side of the aforementioned electrode assembly.

110. An electrode assembly having an anode, a cathode, and a separation membrane sandwiched therebetween wound around a winding shaft to define a core and an outer peripheral surface, characterized in that... The anode, along the winding direction, includes a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. At least a portion of the aforementioned first uncoated portion is used as an electrode tab. The aforementioned first uncoated portion includes multiple segments that can be individually bent, extending from the core side of the electrode assembly towards the outer periphery. When the aforementioned multiple segments are bent along the radial direction of the aforementioned electrode assembly, they are stacked in multiple layers to form a bent surface region. The aforementioned bent surface region, along the radial direction, includes a uniform layer number interval where the number of layers of the aforementioned segment is uniform, and a layer number decreasing interval adjacent to the aforementioned uniform layer number interval where the number of layers of the aforementioned segment decreases as it moves away from the aforementioned uniform layer number interval. The stacking thickness of the sections in the aforementioned uniform stacking range is 100µm to 875µm. in, Cut-off grooves are sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

111. An electrode assembly having an anode, a cathode, and a separation membrane sandwiched therebetween wound around a winding shaft to define a core and an outer peripheral surface, characterized in that, The cathode described above includes, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. At least a portion of the aforementioned first uncoated portion is used as an electrode tab. The first uncoated portion of the electrode assembly includes multiple individually bendable segments extending from the core side along the outer periphery. When the aforementioned multiple segments are bent along the radial direction of the aforementioned electrode assembly, they are stacked in multiple layers to form a bent surface region. The aforementioned bent surface region, along the radial direction, includes a uniform layer number interval where the number of layers of the aforementioned segment is uniform, and a layer number decreasing interval adjacent to the aforementioned uniform layer number interval where the number of layers of the aforementioned segment decreases as it moves away from the aforementioned uniform layer number interval. The stacking thickness of the sections in the above-mentioned uniform stacking range is 50µm to 700µm. in, Cut-off grooves are sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

112. A battery, characterized in that, include: An electrode assembly, wherein a first electrode, a second electrode, and a separation membrane sandwiched therebetween are wound around a winding axis to define a core and an outer peripheral surface, wherein the first electrode includes, along the winding direction, a first active material portion coated with an active material layer and a first uncoated portion without an active material layer, wherein at least a portion of the first uncoated portion is defined as an electrode tab, wherein the first uncoated portion includes a first portion adjacent to the core of the electrode assembly, a second portion adjacent to the outer peripheral surface of the electrode assembly, and a third portion between the first portion and the second portion, wherein, in the winding axis direction, the first portion or the second portion has a smaller height than the third portion; The battery casing includes an open end and an opposite bottom portion, and the electrode assembly is housed in the space between the open end and the bottom portion, and is electrically connected to one of the first electrode and the second electrode, thereby having a first polarity. A sealing element that seals the open end of the aforementioned battery casing; as well as The terminal is electrically connected to the first electrode and another of the second electrodes, has its surface exposed externally, and has a second polarity. In this section, at least a portion of the third part is divided into multiple segments that can be bent individually. Among them, a cutting groove is sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

113. The battery according to claim 112, characterized in that, The height of the second part in the winding axis direction is smaller than that of the third part. The battery casing has an inwardly pressed-in rolled edge in the area adjacent to the open end. The inner surface of the rolled edge, which is opposite to the upper edge of the electrode assembly, is separated from the second part by a predetermined distance.

114. The battery according to claim 113, characterized in that, The pressing depth D1 of the above-mentioned rolled edge and the distance D2 from the inner surface of the above-mentioned battery casing to the boundary point between the above-mentioned second part and the above-mentioned third part satisfy the relationship D1≤D2.

115. The battery according to claim 113, characterized in that, Also includes: Current collector, which is electrically coupled to the third part mentioned above; and An insulator that covers the current collector is fixed in such a way that its edge is sandwiched between the inner surface of the rolled edge and the current collector.

116. The battery according to claim 115, characterized in that, The diameter of the current collector is smaller than the minimum inner diameter of the inner surface of the rolled edge portion, and the diameter of the current collector is the same as or larger than the outermost diameter of the third part.

117. The battery according to claim 115, characterized in that, The current collector is located at a higher position than the rolled edge portion in the winding axis direction.

118. The battery according to claim 112, characterized in that, The aforementioned sealing element includes: a cover that seals the open end of the battery casing; a pad that is sandwiched between the edge of the cover and the open end of the battery casing; and a crimping portion that extends toward the inside of the battery casing and bends and together with the pad surrounds the edge of the cover for fixation, wherein the terminal having the aforementioned second polarity is the cover.

119. The battery according to claim 112, characterized in that, Also includes: The first current collector is electrically connected to the first uncoated portion described above. The aforementioned terminals are provided in a manner that enables insulation in the through-hole formed on the bottom surface of the battery casing, and are rivet terminals that are electrically connected to the first current collector and have the aforementioned second polarity.

120. The battery according to claim 119, characterized in that, Also includes: An insulator is sandwiched between the inner side of the bottom surface of the battery casing and the upper surface of the first current collector to achieve electrical insulation between the inner side of the bottom surface of the battery casing and the first current collector.

121. The battery according to claim 120, characterized in that, The insulator has a thickness corresponding to the distance between the inner side of the bottom surface of the battery casing and the upper surface of the first current collector, and is in close contact with the inner side of the bottom surface of the battery casing and the upper surface of the first current collector.

122. The battery according to claim 120, characterized in that, The terminal includes a flat portion at its lower end, and the insulator includes an opening for exposing the flat portion, which is soldered to the first current collector through the opening.

123. The battery according to claim 112, characterized in that, The second electrode, along the winding direction, includes a second active material portion coated with an active material layer and a second uncoated portion without an active material layer. The second electrode has the first polarity. At least a portion of the second uncoated portion is defined as an electrode tab. The battery further includes a second current collector electrically connected to the second uncoated portion. At least a portion of the edge of the second current collector is attached to the sidewall of the battery casing.

124. The battery according to claim 119, characterized in that, The second electrode, along the winding direction, includes a second active material portion coated with an active material layer and a second uncoated portion without an active material layer. The second electrode has the first polarity. At least a portion of the second uncoated portion is defined as an electrode tab. The battery further includes a second current collector electrically connected to the second uncoated portion. At least a portion of the edge of the second current collector is attached to the sidewall of the battery casing. The outer diameter of the first current collector is the same as or larger than that of the second current collector.

125. The battery according to claim 124, characterized in that, The first current collector and the second current collector are welded to the first uncoated portion and the second uncoated portion along the radial direction of the electrode assembly to form a welding pattern, wherein the length of the welding pattern of the first current collector is longer than the length of the welding pattern of the second current collector.

126. The battery according to claim 125, characterized in that, The welding patterns of the first current collector and the second current collector are located at substantially the same distance from the core center of the electrode assembly.

127. The battery according to claim 123, characterized in that, The battery casing has an inwardly pressed-in rolled edge on the inner wall adjacent to the open end, and the edge of the second current collector is electrically connected to the rolled edge.

128. The battery according to claim 127, characterized in that, The area where the second current collector makes electrical contact with the second uncoated portion is located inside the inner surface of the rolled edge portion.

129. The battery according to claim 127, characterized in that, include: The cover has its edges supported by the aforementioned rolled edge and is non-polar; A pad is sandwiched between the edge of the cover and the open end of the battery casing; as well as The crimping portion extends and bends inward toward the open end of the battery casing, and together with the pad, surrounds the edge of the cover for fixation. The edge of the second current collector is fixed by being clamped between the rolled edge and the pad by the crimping part.

130. The battery according to claim 127, characterized in that, The edge of the second current collector is welded to the rolled edge.

131. The battery according to claim 112, characterized in that, The second part described above is divided into multiple segments that can be bent individually. The first uncoated portion of the segment is divided into multiple segments, and the height of the segment varies in stages along a direction parallel to the winding direction, from a first height h1 to a (N-1)th height h. N-1 The height variable range and uniformly maintaining the Nth height h N The height is uniformly distributed within a range, where N is the height index and is a natural number greater than 2, h N Greater than h N-1 .

132. The battery according to claim 131, characterized in that, The N mentioned above is between 2 and 30.

133. The battery according to claim 131, characterized in that, With height h k The number of slices is multiple, with a height h k Multiple segments are configured on one or more winding loops, where k is a natural number from 1 to N.

134. The battery according to claim 131, characterized in that, In the case of containing a height h k The starting radius of the winding loop of the cut piece is defined as r. k At that time, more than 90% of the diameter of the core of the aforementioned electrode assembly is not located in the aforementioned r k The folded portion of the slice is occluded, where k is a natural number from 1 to N.

135. The battery according to claim 131, characterized in that, In the case of containing a height h k The starting radius of the winding loop of the cut piece is r. k The core has a radius of r c At that time, the height h of the slice k Satisfy the following mathematical expression: 2mm≤h k ≤r k -a r c , Where k is a natural number from 1 to N, and α is from 0.90 to 1.

136. The battery according to claim 131, characterized in that, When the radius of the winding loop containing the cut piece, with the core center of the aforementioned electrode assembly as the reference, is defined as r, and the width of the cut piece in the winding direction is defined as D(r), D(r) satisfies the following mathematical expression: 1 mm ≤ D (r) ≤ (2 π (360°) 45°.

137. The battery according to claim 131, characterized in that, The height of the aforementioned multiple segments increases with the radius r of the winding loop containing the segment, which is based on the core center of the aforementioned electrode assembly, and the width of the segment in the winding direction gradually or in stages increases or decreases.

138. The battery according to claim 131, characterized in that, As the radius r of the winding loop containing the segments referenced to the core center of the aforementioned electrode assembly increases, the height of the aforementioned segments first gradually or in stages increases and then gradually or in stages decreases, or vice versa.

139. The battery according to claim 131, characterized in that, Each of the aforementioned segments has a geometric shape in which the lower width is greater than the upper width, and the lower interior angle θ of the segment located in the winding loop of radius r centered on the core of the aforementioned electrode assembly belongs to the angle range of the following mathematical formula: ， Where D is the width of the slice in the winding direction; r is the radius of the winding loop containing the slice; H is the height of the slice; and p is the spacing between the slices.

140. The battery according to claim 139, characterized in that, As the direction approaches a direction parallel to the aforementioned winding direction, the lower interior angles of the plurality of segments increase individually or in groups within a range of 60 to 85 degrees.

141. The battery according to claim 131, characterized in that, Within the aforementioned variable height range and the aforementioned uniform height range, the maximum height h of the sectional slice is... max Satisfy the following mathematical expression: h max ≤W foil –W scrap，min W margin，min –W gap , Among them, W foil It is the width of the current collector foil before the stencil is formed; W scrap，min It is the width equivalent to the minimum chip breaking allowance when cutting the current collector foil to form the slit; W margin，min It is the width corresponding to the minimum serpentine allowance of the separation membrane; W gap It is equivalent to the width of the insulating gap between the end of the second electrode, which is opposite to the first electrode and separated by the separation membrane, and the end of the separation membrane.

142. The battery according to claim 141, characterized in that, When the first electrode is the anode, the insulation gap W gap It ranges from 0.2mm to 6mm.

143. The battery according to claim 141, characterized in that, When the first electrode is a cathode, the insulation gap W gap It ranges from 0.1mm to 2mm.

144. The battery according to claim 141, characterized in that, Minimum chip breaking allowance W scrap，min It ranges from 1.5mm to 8mm.

145. The battery according to claim 141, characterized in that, The minimum serpentine margin W of the above separation membrane margin，min It is 0 to 1 mm.

146. The battery according to claim 141, characterized in that, The minimum chip breaking allowance mentioned above is 0.

147. The battery according to claim 141, characterized in that, The height of the segments configured in the above-mentioned variable height range gradually or in stages increases within the range of 2mm to 10mm.

148. The battery according to claim 112, characterized in that, The second part is divided into multiple segments that can be bent individually. Based on the cross section along the winding axis, the electrode assembly in the radial direction includes, in sequence, a segment omission section without segments, a height variable section with variable segment height, and a height uniform section with uniform segment height. The multiple segments are arranged in the height variable section and the height uniform section, and are bent along the radial direction of the electrode assembly to form a bent surface area.

149. The battery according to claim 148, characterized in that, The first part mentioned above was not divided into multiple segments, and the omitted intervals of the segments mentioned above correspond to the first part mentioned above.

150. The battery according to claim 148, characterized in that, In the radial direction of the aforementioned electrode assembly, the ratio of the radial length of the omitted section of the aforementioned sectional section to the radius of the aforementioned electrode assembly excluding the aforementioned core is 10% to 40%.

151. The battery according to claim 148, characterized in that, In the radial direction of the aforementioned electrode assembly, the ratio of the radial length of the aforementioned height-variable range to the radial length corresponding to the aforementioned height-variable range and the aforementioned height-uniform range is 1% to 50%.

152. The battery according to claim 148, characterized in that, The ratio of the length of the electrode region corresponding to the omitted section of the above-mentioned sectional view to the overall length of the first electrode is 1% to 30%.

153. The battery according to claim 148, characterized in that, The ratio of the length of the electrode region corresponding to the aforementioned height-variable range to the overall length of the aforementioned first electrode is 1% to 40%.

154. The battery according to claim 148, characterized in that, The ratio of the length of the electrode region corresponding to the aforementioned height uniformity interval to the overall length of the aforementioned first electrode is 50% to 90%.

155. The battery according to claim 131, characterized in that, As the multiple pieces approach a direction parallel to the winding direction of the aforementioned electrode assembly, they form multiple piece groups, and the width in the winding direction and the height in the winding axis direction of the multiple pieces belonging to the same piece group are substantially the same.

156. The battery according to claim 155, characterized in that, As the direction approaches parallel to the winding direction of the aforementioned electrode assembly, at least one of the width of the winding direction and the height of the winding axis direction of the multiple slices belonging to the same slice group increases in stages.

157. The battery according to claim 155, characterized in that, When the width of each of three consecutive adjacent cutter groups along a direction parallel to the winding direction of the aforementioned electrode assembly is set to W1, W2, and W3, it includes combinations of cutter groups that are smaller than W2 / W1 compared to W3 / W2.

158. The battery according to claim 148, characterized in that, Taking the core center of the aforementioned electrode assembly as a reference, when the number of segments intersecting with a virtual line parallel to the winding axis at any radius position in the aforementioned bent surface region is defined as the number of segments stacked at the corresponding radius position, the aforementioned bent surface region includes a uniform stacking interval where the number of segments stacked is uniform from the core side to the outer periphery side, and a stacking reduction interval that is adjacent to the aforementioned uniform stacking interval and where the number of segments stacked decreases as it moves away from the aforementioned uniform stacking interval.

159. The battery according to claim 158, characterized in that, Within the aforementioned uniform range of stacking numbers, the stacking number of the aforementioned sections is 10 or more.

160. The battery according to claim 158, characterized in that, Within the aforementioned uniform range of stacking numbers, the stacking number of the above-mentioned sections is between 10 and 35.

161. The battery according to claim 158, characterized in that, With the core center of the aforementioned electrode assembly as a reference, the starting radius of the aforementioned uniform stacking interval corresponds to the starting radius of the aforementioned variable height interval.

162. The battery according to claim 158, characterized in that, The ratio of the radial length of the uniform stacking interval to the radial length of the uniform stacking interval and the decreasing stacking interval is 30% to 85%.

163. The battery according to claim 158, characterized in that, The first electrode is the anode, and within the uniform stacking range, the stacking thickness of the sectional section is 100 μm to 875 μm.

164. The battery according to claim 158, characterized in that, Also includes: A current collector is welded within the aforementioned uniform layer number region, such that at least a portion of the uniform layer number region overlaps with the welded area. The first electrode mentioned above is the anode, and in the welding area mentioned above, the stacking thickness of the slab is 100um to 875um.

165. The battery according to claim 158, characterized in that, The first electrode is a cathode, and within the uniform stacking range, the stacking thickness of the sectional section is 50 μm to 700 μm.

166. The battery according to claim 158, characterized in that, Also includes: A current collector is welded within the aforementioned uniform layer number region, such that at least a portion of the uniform layer number region overlaps with the welded area. The first electrode mentioned above is a cathode, and the stacking thickness of the slab in the welding area is 50 μm to 700 μm.

167. The battery according to claim 112, characterized in that, The second part is also divided into multiple segments that can be bent individually. A cutting groove is sandwiched between multiple adjacent segments along the winding direction. The lower part of the cutting groove includes: a bottom; and chamfered portions connecting the two ends of the bottom and the sides of the segments located on both sides of the cutting groove.

168. The battery according to claim 167, characterized in that, The radius of curvature of the chamfered portion is greater than 0 and less than 0.1 mm.

169. The battery according to claim 167, characterized in that, The radius of curvature of the chamfered portion is 0.01 mm to 0.05 mm.

170. The battery according to claim 167, characterized in that, The bottom is flat.

171. The battery according to claim 167, characterized in that, The separation interval, defined as the distance between two points where the lines extending from the sides of the two segments located on both sides of the cut-off groove and the line extending from the bottom of the cut-off groove intersect, is 0.05 mm to 1.00 mm.

172. The battery according to claim 167, characterized in that, The aforementioned multiple segments are made of aluminum foil, and the separation interval, defined by the distance between the two points where the lines extending from the sides of the two segments located on both sides of the aforementioned cutting groove intersect and the line extending from the lower end of the aforementioned cutting groove, is 0.5 mm to 1.00 mm.

173. The battery according to claim 167, characterized in that, The bottom of the aforementioned cut-off groove is separated from the aforementioned active material layer by a certain distance.

174. The battery according to claim 173, characterized in that, The separation distance between the bottom of the cut-off groove and the active material layer is 0.2 mm to 4 mm.

175. The battery according to claim 167, characterized in that, The aforementioned multiple segments are bent along the radial direction of the aforementioned electrode assembly within a 0 to 1 mm range above the bottom of the cut-off groove.

176. The battery according to claim 167, characterized in that, The aforementioned insulating coating comprises a polymer resin and inorganic fillers dispersed in the aforementioned polymer resin.

177. The battery according to claim 167, characterized in that, The insulating coating is formed to cover the boundary portion between the active material layer and the first uncoated portion along the winding direction.

178. The battery according to claim 177, characterized in that, The insulating coating is formed to cover the boundary between the active material layer and the first uncoated portion with a width of 0.3 mm to 5 mm along the winding axis.

179. The battery according to claim 167, characterized in that, The end of the aforementioned insulating coating is located within a range of -2 mm to 2 mm along the winding axis, with the end of the aforementioned separating membrane as a reference.

180. The battery according to claim 179, characterized in that, The aforementioned insulating coating is exposed on the outside of the aforementioned separation membrane.

181. The battery according to claim 167, characterized in that, The lower end of the cut-off groove is separated from the insulating coating by a distance of 0.5 mm to 2 mm.

182. The battery according to claim 181, characterized in that, The end of the aforementioned insulating coating in the winding axis direction is located within the range of -2mm to +2mm, with the lower end of the aforementioned cut-off groove as a reference.

183. The battery according to claim 158, characterized in that, Also includes: The current collector is welded to the aforementioned bent surface area. In the radial direction of the electrode assembly, the welding area of ​​the current collector overlaps with the uniform stacking interval by at least 50%.

184. The battery according to claim 183, characterized in that, In the radial direction of the aforementioned electrode assembly, the area in the welding region of the aforementioned current collector that does not overlap with the aforementioned uniform stacking interval overlaps with the aforementioned reduced stacking interval.

185. The battery according to claim 183, characterized in that, The edge of the current collector is welded to the bent surface region in such a way that it covers the end of the bent portion of the outermost segment in the radial direction of the electrode assembly.

186. The battery according to claim 183, characterized in that, The welding strength of the welding area of ​​the aforementioned current collector is 2 kgf / cm². 2 above.

187. The battery according to claim 183, characterized in that, The welding strength of the welding area of ​​the aforementioned current collector is 4 kgf / cm². 2 above.

188. The battery according to claim 112, characterized in that, The first uncoated portion is made of metal foil, the metal foil having an elongation of 1.5% to 3.0% and a tensile strength of 25 kgf / mm². 2 Up to 35 kgf / mm 2 .

189. The battery according to claim 188, characterized in that, The aforementioned metal foil is aluminum foil.

190. The battery according to claim 188, characterized in that, The bending length of the first electrode is less than 20 mm.

191. The battery according to claim 112, characterized in that, The ratio of the length of the short side parallel to the winding axis direction to the length of the long side parallel to the winding direction of the first active material portion is 1% to 4%.

192. A battery, characterized in that, include: An electrode assembly, comprising a first electrode, a second electrode, and a separation membrane sandwiched between them, is wound around a winding shaft to define a core and an outer peripheral surface. The first electrode, along the winding direction, includes a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. The first uncoated portion, from the core side of the electrode assembly along the outer peripheral side, includes a section divided into multiple segments capable of being individually bent. The multiple segments are bent along the radial direction of the electrode assembly to form a bending surface region. The bending surface region, along the radial direction, includes a uniform layer number range where the number of layers of the segments is 10 or more, and a layer number reduction range adjacent to the uniform layer number range where the number of layers of the segments decreases as they move away from the uniform layer number range. The battery casing includes an open end and a bottom part opposite thereto, and the electrode assembly is housed in the space between the open end and the bottom part, and is electrically connected to one of the first electrode and the second electrode and has a first polarity. A sealing element that seals the open end of the aforementioned battery casing; and The terminal, which is electrically connected to the first electrode and another of the second electrodes, has an exposed surface and a second polarity. Among them, a cutting groove is sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

193. A battery, characterized in that, include: An electrode assembly, comprising an anode, a cathode, and a separation membrane sandwiched between them, is wound around a winding shaft to define a core and an outer peripheral surface. The anode, along the winding direction, includes a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. At least a portion of the first uncoated portion is used as an electrode tab. The first uncoated portion includes multiple individually bendable segments along the outer peripheral side from the core side of the electrode assembly. When the multiple segments are bent along the radial direction of the electrode assembly, they are stacked in multiple layers to form a bending surface region. The bending surface region, along the radial direction, includes a uniform stacking interval where the number of stacked segments is uniform and a stacking reduction interval adjacent to the uniform stacking interval where the number of stacked segments decreases as it moves away from the uniform stacking interval. The stacking thickness of the segments in the uniform stacking interval is 100 μm to 875 μm. The battery casing includes an open end and an opposite bottom portion, and the electrode assembly is housed in the space between the open end and the bottom portion, and is electrically connected to one of the anode and the cathode to have a first polarity. A sealing element that seals the open end of the aforementioned battery casing; and The terminal, which is electrically connected to another of the aforementioned anode and cathode, has an exposed surface and a second polarity. Among them, a cutting groove is sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

194. The battery according to claim 193, characterized in that, The electrode assembly further includes a current collector welded to the uniform stacking interval so that the uniform stacking interval overlaps with the welding area, wherein the stacking thickness of the sectional piece in the welding area is 100 μm to 875 μm.

195. A battery, characterized in that, include: An electrode assembly, comprising an anode, a cathode, and a separation membrane sandwiched between them, is wound around a winding shaft to define a core and an outer peripheral surface. The cathode, along the winding direction, includes a first active material portion coated with an active material layer and a first uncoated portion without an active material layer. At least a portion of the first uncoated portion is used as an electrode tab. The first uncoated portion includes multiple individually bendable segments along the outer peripheral side from the core side of the electrode assembly. When the multiple segments are bent along the radial direction of the electrode assembly, they are stacked in multiple layers to form a bending surface region. The bending surface region, along the radial direction, includes a uniform stacking interval where the number of stacked segments is uniform and a decreasing stacking interval adjacent to the uniform stacking interval where the number of stacked segments decreases as it moves away from the uniform stacking interval. The stacking thickness of the segments in the uniform stacking interval is 50 μm to 700 μm. The battery casing includes an open end and an opposite bottom portion, and the electrode assembly is housed in the space between the open end and the bottom portion, and is electrically connected to one of the anode and the cathode to have a first polarity. A sealing element that seals the open end of the aforementioned battery casing; and The terminal, which is electrically connected to another of the aforementioned anode and cathode, has an exposed surface and a second polarity. Among them, a cutting groove is sandwiched between adjacent segments along the aforementioned winding direction, and An insulating coating is formed at the boundary between the uncoated portion and the active material layer in the region within the area separating the bottom of the cut-off groove from the active material layer.

196. The battery according to claim 195, characterized in that, The electrode assembly further includes a current collector welded to the uniform stacking interval so that the uniform stacking interval and the welding area overlap, wherein the stacking thickness of the sectional piece in the welding area is 50 μm to 700 μm.

197. A battery pack, characterized in that, It includes a plurality of batteries according to any one of claims 112 to 196.

198. The battery pack according to claim 197, characterized in that, The ratio of the diameter to the height of the aforementioned battery is greater than 0.

4.

199. The battery pack according to claim 198, characterized in that, The shape factor of the aforementioned battery is 46110, 4875, 48110, 4880, or 4680.

200. The battery pack according to claim 197, characterized in that, The resistance of the aforementioned battery is below 4mΩ.

201. The battery pack according to claim 197, characterized in that, Multiple batteries are configured to be arranged in a specified number of columns, with the terminals of each battery and the outer surface of the bottom of the battery casing facing upwards.

202. The battery pack according to claim 201, characterized in that, The battery pack includes multiple buses that connect multiple batteries in series and in parallel. The multiple buses are arranged on the upper part of the multiple batteries. Each bus includes: a main body that extends between multiple terminals of adjacent batteries; multiple first bus terminals that extend to one side of the main body and are electrically connected to the terminals of the batteries located in the one side direction; and multiple second bus terminals that extend to the other side of the main body and are electrically connected to the outer surface of the bottom surface of the battery casing of the batteries located in the other side direction.

203. A car, characterized in that, The battery pack includes any one of claims 197 to 202.

Images