Electrode assembly, cylindrical battery cell, and battery pack and vehicle including same

Abstract

Disclosed are an electrode assembly, a cylindrical battery cell, and a battery pack and a vehicle including the cylindrical battery cell. The electrode assembly is a winding core type electrode assembly having a structure in which first and second electrode plates having a sheet shape and a separator interposed therebetween are wound in one direction, in which at least one of the first and second electrode plates includes an uncoated portion not coated with an active material layer on a long-side end portion. At least a portion of the uncoated portion serves as an electrode tab. Further, the uncoated portion includes a core-side uncoated portion adjacent to the core of the electrode assembly, an outer-circumferential-side uncoated portion adjacent to the outer-circumferential surface of the electrode assembly, and an intermediate uncoated portion interposed between the core-side uncoated portion and the outer-circumferential-side uncoated portion. Preferably, at least one of the core-side uncoated portion and the outer-peripheral-side uncoated portion has a relatively smaller height in the winding axis direction than the intermediate uncoated portion.

Description

Technical Field

[0001] The present disclosure relates to an electrode assembly, a cylindrical battery cell, a battery pack, and a vehicle including the battery pack. Background Art

[0002] Secondary batteries that can be easily applied to various product groups and have electrical characteristics such as high energy density are widely used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electric drive sources.

[0003] These secondary batteries are attracting attention as new energy sources for improving eco-friendliness and energy efficiency because they have the main advantage of being able to significantly reduce the use of fossil fuels and the secondary advantage of not producing by-products during energy use.

[0004] Secondary batteries currently widely used in the art include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. A single secondary battery cell (i.e., a single battery cell) has an operating voltage of about 2.5V to 4.5V. Therefore, when a higher output voltage is required, multiple battery cells can be connected in series to form a battery pack. In addition, depending on the charge / discharge capacity required for the battery pack, multiple battery cells can be connected in parallel to form a battery pack. Therefore, the number and form of electrical connection of the battery cells included in the battery pack can be set in various ways according to the required output voltage and / or charge / discharge capacity.

[0005] Meanwhile, as a type of single secondary battery cell, cylindrical, rectangular, and pouch-type battery cells are known. In the case of a cylindrical battery cell, a separator serving as an insulator is inserted between the positive electrode and the negative electrode, and they are wound to form a wound core-shaped electrode assembly, and the electrode assembly is inserted into a battery can to provide a battery. In addition, strip-shaped electrode connectors can be connected to the uncoated portions of each of the positive electrode and the negative electrode, and the electrode connectors electrically connect the electrode assembly and the electrode terminals exposed to the outside. For reference, the positive electrode terminal is the cover plate of the sealing body that seals the opening of the battery can, and the negative electrode terminal is the battery can. However, according to the conventional cylindrical battery cell having such a structure, since the current is concentrated in the strip-shaped electrode connectors connected to the uncoated portion of the positive electrode and / or the uncoated portion of the negative electrode, the current collection efficiency is poor due to a large resistance and a large amount of heat generation.

[0006] For small cylindrical battery cells with a form factor of 18650 or 21700, resistance and heat are not major problems. However, when the form factor is increased to apply the cylindrical battery cell to an electric vehicle, during a rapid charging process, the cylindrical battery cell may catch fire in the case of a large amount of heat generation around the electrode connectors.

[0007] To solve this problem, a cylindrical battery cell (a so-called jointless cylindrical battery cell) is provided, in which the uncoated portions of the positive electrode and the negative electrode are designed to be located at the top and bottom of the wound electrode assembly, respectively, and current collector plates are welded to the uncoated portions to improve the current collection efficiency.

[0008] Figures 1 to 3 is a view showing the process of manufacturing a jointless cylindrical battery cell. Figure 1 shows the structure of the electrode plate, Figure 2 shows the process of winding the electrode plate, and Figure 3 shows the process of welding the current collector plate to the curved surface of the uncoated portion.

[0009] Referring to Figures 1 to 3 , the positive electrode plate 10 and the negative electrode plate 11 have a structure in which a sheet-like current collector 20 is coated with an active material 21, and an uncoated portion 22 is included at one long side in the winding direction X.

[0010] As Figure 2 shown, the electrode assembly A is manufactured by sequentially laminating the positive electrode plate 10 and the negative electrode plate 11 together with two separator films 12 and then winding them in one direction X. At this time, the uncoated portions of the positive electrode plate 10 and the negative electrode plate 11 are arranged in opposite directions. Here, one direction X refers to the winding direction based on the axis.

[0011] After the winding process, the uncoated portion 10a of the positive electrode plate 10 and the uncoated portion 11a of the negative electrode plate 11 are bent toward the core. Thereafter, the current collector plates 30, 31 are respectively welded and connected to the uncoated portions 10a, 11a.

[0012] Electrode joints are not separately connected to the positive electrode uncoated portion 10a and the negative electrode uncoated portion 11a. The current collector plates 30, 31 are connected to external electrode terminals, and a current path having a large cross-sectional area is formed along the winding axis direction of the electrode assembly A (see the arrow), which has the advantage of reducing the resistance of the battery cell. This is because the resistance is inversely proportional to the cross-sectional area of the path through which the current flows.

[0013] In the jointless cylindrical battery cell, in order to improve the welding characteristics between the uncoated portions 10a, 11a and the current collector plates 30, 31, a strong pressure must be applied to the welding areas of the uncoated portions 10a, 11a to bend the uncoated portions 10a, 11a as flat as possible.

[0014] However, when the welding areas of the uncoated portions 10a and 11a are bent, the shapes of the uncoated portions 10a and 11a may be irregularly distorted and deformed. In this case, the deformed portions may come into contact with the electrode plates of the opposite polarity, causing an internal short circuit, or microcracks may be caused in the uncoated portions 10a and 11a. In addition, when the uncoated portion 32 adjacent to the core of the electrode assembly A is bent, all or most of the cavity 33 in the core of the electrode assembly A is blocked. In this case, problems occur during the electrolyte injection process. That is, the cavity 33 in the core of the electrode assembly A serves as a channel for injecting the electrolyte. However, if the corresponding channel is blocked, it is difficult to inject the electrolyte. In addition, when the electrolyte injector is being inserted into the cavity 33, the electrolyte injector may interfere with the uncoated portion 32 near the core, which may cause the uncoated portion 32 to tear.

[0015] In addition, the bent portions of the uncoated portions 10a and 11a to which the current collectors 30 and 31 are welded should overlap in multiple layers, and there should be no empty spaces (gaps). In this way, sufficient welding strength can be obtained, and even with the latest technologies such as laser welding, it is possible to prevent the laser from penetrating into the electrode assembly A and melting the separator or the active material.

[0016] Meanwhile, in a conventional non-jointed cylindrical battery cell, the uncoated portion 10a of the positive electrode is integrally formed on the upper part of the electrode assembly A. Therefore, when the outer periphery of the top of the battery can is pressed inward to form a curled edge portion, the top edge region 34 of the electrode assembly A is compressed by the battery can. This compression may cause local deformation of the electrode assembly A, which may tear the separator 12 and cause an internal short circuit. If a short circuit occurs inside the battery, it may cause the battery to heat up or explode.

[0017] Conventional separators use a coating containing inorganic particles to improve the thermal shrinkage characteristics of the porous polymer substrate, but at this time it is a single-sided inorganic coating separator with a coating only on one side of the porous polymer substrate. Since this inorganic coating separator is configured such that one side is a fabric and the other side is an inorganic (ceramic) coating when facing the electrodes in the wound core (J / R), the impregnation characteristics for the electrolyte are asymmetric. Due to this electrolyte impregnation asymmetry, there are problems in managing the matching of the separator when designing the positive and negative electrodes, and there are problems of increased costs due to the need to increase the pressure / vacuum conditions when impregnating the electrolyte with the wound core, and there are also problems of performance degradation.

[0018] In addition, conventional single-sided inorganic-coated separators have a large shrinkage rate at a high temperature of 130 °C or higher because the side of the separator made of fabric is exposed and has limited heat resistance. Therefore, when a thermal shock (at 130 °C or above) occurs, an internal electrode short circuit is caused due to the shrinkage of the separator, and when the internal temperature of the battery cell increases due to an abnormal reaction (overcharge, external short circuit), the risk of ignition increases.

[0019] In addition, after assembling an unslotted wound core, since an inner and outer closed structure is formed by folding a foil serving as a current collector, when an electrolyte is injected, the electrolyte moving toward the electrode in the wound core is disturbed, which exhibits non-uniform electrolyte impregnation performance. We found that this is due to the occurrence of non-uniform electrolyte impregnation paths during the electrolyte impregnation process. Therefore, the problem lies in that an unstable solid electrolyte interface (SEI) layer is formed due to an increase in cell-to-cell variation caused by a decrease in impregnation uniformity, and the resistance dispersion increases. Summary of the Invention

[0020] Technical Problem

[0021] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure aims to provide an electrode assembly having improved impregnation performance.

[0022] The present disclosure also aims to provide an electrode assembly having an improved uncoated portion structure to relieve the stress applied to the uncoated portion when bending the uncoated portions exposed at both ends of the electrode assembly.

[0023] The present disclosure also aims to provide an electrode assembly in which even when the uncoated portion is bent, the electrolyte injection channel is not blocked.

[0024] The present disclosure also aims to provide an electrode assembly including a structure that can prevent the top edge of the electrode assembly from contacting the inner surface of the battery can when the top of the battery can is curled.

[0025] The present disclosure also aims to provide an electrode assembly having increased energy density and reduced resistance.

[0026] The present disclosure also aims to provide a cylindrical battery cell, a battery pack including the cylindrical battery cell, and a vehicle including the battery pack, the cylindrical battery cell including an electrode assembly having an improved structure.

[0027] The technical problems to be solved by the present disclosure are not limited to the above, and those skilled in the art can clearly understand other objects not mentioned herein through the following disclosure.

[0028] Technical Solution

[0029] The present disclosure relates to an electrode assembly for an electrochemical device. In a first aspect of the present disclosure, the electrode assembly includes a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate,

[0030] wherein the first electrode plate, the second electrode plate, and the separator are wound together in one direction around an axis to have a plurality of winding turns,

[0031] wherein each of the first electrode plate and the second electrode plate includes a first side and a second side, and the first side and the second side are disposed opposite to each other in the direction of the axis,

[0032] wherein each of the first electrode plate and the second electrode plate further includes a first portion and a second portion, the first portion is an electrode active material portion coated with an electrode active material and extends from the second side towards the first side,

[0033] wherein the second portion is an uncoated portion not coated with an electrode active material and extends from the first side towards the second side to the electrode active material portion of the first portion,

[0034] wherein at least a partial region of the uncoated portion is divided into a plurality of segments by a cut groove having a predetermined depth,

[0035] wherein the segment has a first end corresponding to the first side,

[0036] wherein all or part of the segments are bent in a radial direction relative to the axis at a bending point, and the bending point is a point below the first end in each segment,

[0037] wherein among the segments, the bent segments are referred to as bent segments,

[0038] wherein for the smallest bent segment having the smallest height among the bent segments,

[0039] the end of the separator in the width direction is located within 50% of the height based on the baseline of the smallest bent segment in the outer direction of the electrode assembly, or the end of the separator in the width direction is located within 30% of the height based on the baseline of the smallest bent segment in the inner direction of the electrode assembly. The baseline is a straight line extending in the winding direction (X) and the height corresponds to the notch valley of the cut groove, and wherein when the first electrode plate is the positive electrode plate and the second electrode plate is the negative electrode plate, the width of the electrode active material portion of the positive electrode plate is equal to or less than the width of the electrode active material portion of the negative electrode plate.

[0040] In a second aspect of the present disclosure, one end of the separator may be located between the bending point of each segment and the boundary between the first portion and the second portion.

[0041] In a third aspect of the present disclosure, according to the first aspect or the second aspect, one end of the separator may be positioned such that the cut valley of the cut groove between the segments is covered by the separator and not exposed.

[0042] In a fourth aspect of the present disclosure, according to the second aspect or the third aspect, the bending point may be a specific point between the first end portion and the baseline, and the baseline may be a straight line extending in the winding direction (X) and having a height corresponding to the cut valley of the cut groove.

[0043] In a fifth aspect of the present disclosure, according to any one of the first aspect to the fourth aspect,

[0044] In each of the first electrode plate and the second electrode plate, the length from the baseline to the first end portion of the segment may vary according to the winding direction.

[0045] In a sixth aspect of the present disclosure, according to any one of the first aspect to the fifth aspect, among the bent segments, the segments in the adjacent winding turns may be continuously overlapped in the radial direction or the direction opposite thereto to form a surface area at the top or bottom end of the electrode assembly in the winding axis direction,

[0046] and when the shortest distance between the highest point of the surface area and the baseline is the height (HS) of the surface area,

[0047] One end of the separator may be within 90% of the height (HS) based on the baseline of the surface area in the first side direction of the electrode assembly or below the baseline in the second side direction of the electrode assembly.

[0048] In a seventh aspect of the present disclosure, according to any one of the first aspect to the sixth aspect, among the bent segments, the segments in the adjacent winding turns may be continuously overlapped in the radial direction or the direction opposite thereto to form a surface area at the top or bottom end of the electrode assembly in the winding axis direction,

[0049] and when the number of segments intersecting a virtual line parallel to the winding axis direction at an arbitrary radial position based on the center of the core of the electrode assembly in the surface area is defined as the segment stacking number at the corresponding radial position, the surface area may include a stacking number uniform area where the segment stacking number is uniform along the radius from the center of the core of the electrode assembly to the outer periphery and a stacking number decreasing area located outside the stacking number uniform area where the segment stacking number decreases toward the outer periphery.

[0050] In an eighth aspect of the present disclosure, according to any one of the first to seventh aspects, in the region where the number of stacked layers is uniform, the number of stacked segments can be 10 or more. In a ninth aspect of the present disclosure, according to any one of the first to eighth aspects, the uncoated portion may include a core-side uncoated portion adjacent to the core of the electrode assembly, a peripheral uncoated portion adjacent to the outer peripheral surface of the electrode assembly, and an intermediate uncoated portion interposed between the core-side uncoated portion and the peripheral uncoated portion,

[0051] and at least one of the core-side uncoated portion and the peripheral uncoated portion has a relatively smaller length from the baseline to the first side surface than the intermediate uncoated portion.

[0052] In a tenth aspect of the present disclosure, according to any one of the first to ninth aspects, the core-side uncoated portion has a relatively smaller length from the baseline to the first side surface than the intermediate uncoated portion and the peripheral uncoated portion.

[0053] In an eleventh aspect of the present disclosure, according to the ninth or tenth aspect, the height of the core-side uncoated portion may correspond to the baseline.

[0054] In a twelfth aspect of the present disclosure, according to any one of the ninth to eleventh aspects, the core-side uncoated portion may include an uncoated portion located in a portion of the electrode plate corresponding to the innermost wound turn of the electrode assembly,

[0055] and the peripheral uncoated portion may include an uncoated portion located in a portion of the electrode plate corresponding to the outermost wound turn of the electrode assembly.

[0056] In a thirteenth aspect of the present disclosure, according to any one of the ninth to twelfth aspects, all or at least a part of the region of the intermediate uncoated portion may be divided into a plurality of segments.

[0057] In a fourteenth aspect of the present disclosure, according to any one of the first to thirteenth aspects, the distance between the bending point and the separator may be 0.1 mm or more.

[0058] In a fifteenth aspect of the present disclosure, according to any one of the first to fourteenth aspects, the width of the electrode active material portion of the positive electrode plate may be set within the width of the electrode active material portion of the negative electrode plate.

[0059] In a sixteenth aspect of the present disclosure, according to any one of the first to fifteenth aspects, at least one of the first electrode and the second electrode plate may have a sliding portion formed at one end in the width direction of the electrode active material portion.

[0060] In the seventeenth aspect of the present disclosure, according to any one of the first aspect to the sixteenth aspect, the distance from the first end of the minimum bending segment to the baseline may be 2 mm or greater.

[0061] In the eighteenth aspect of the present disclosure, according to any one of the first aspect to the seventeenth aspect, in the minimum bending segment, the length from the baseline to the bending line may be equal to or longer than the length from the bending line to the first end.

[0062] And the bending point may be the point where the inclination angle of the tangent line in the part generated by bending the segment toward the winding center by using an external force starts to be less than or equal to 45°, and the inclination angle of the tangent line may be the angle between the tangent line to the bending point and the plane perpendicular to the winding axis of the electrode assembly.

[0063] In the nineteenth aspect of the present disclosure, according to the eighteenth aspect, in the minimum bending segment, the length from the baseline to the bending line may be equal to or less than the length from the bending line to the first end of the minimum bending segment.

[0064] The bending line may be a line parallel to the baseline and including the bending point, and the bending point may be the point where the inclination angle of the tangent line in the part generated by bending the segment toward the winding center by using an external force starts to be less than or equal to 45°, and the inclination angle of the tangent line may be the angle between the tangent line to the bending point and the plane perpendicular to the winding axis of the electrode assembly.

[0065] In the twentieth aspect of the present disclosure, according to any one of the first aspect to the nineteenth aspect, the electrode assembly may further include a segment (segment A) with a height less than that of the minimum bending segment, or may not include any segment with a height less than that of the minimum bending segment such that the minimum bending segment is the minimum segment with the minimum height, and the height of the segment may be the shortest length from the baseline to the first end of the segment.

[0066] In the twenty - first aspect of the present disclosure, according to the twentieth aspect, compared with other segments among the multiple segments, segment A may be arranged closer to the core.

[0067] In the twenty - second aspect of the present disclosure, according to any one of the ninth aspect to the twenty - first aspect, at least a partial region of the intermediate uncoated portion may be configured to have a height in the winding axis direction that gradually increases from the core to the periphery.

[0068] In the twenty - third aspect of the present disclosure, according to any one of the first aspect to the twenty - second aspect, each of the multiple segments may have a rectangular structure, a trapezoidal structure, a triangular structure, an equilateral quadrilateral structure, a semi - circular structure, or a semi - elliptical structure.

[0069] In a twenty-fourth aspect of the present disclosure, according to any one of the first to twenty-third aspects, each of the plurality of segments may have a trapezoidal shape, and the plurality of segments may be configured such that the lower interior angles of their trapezoidal shapes increase individually or in groups from the core to the outer periphery.

[0070] In a twenty-fifth aspect of the present disclosure, according to any one of the first to twenty-fourth aspects, at least one of the height of the plurality of segments in the winding axis direction and the width in the winding direction may increase step by step individually or in groups from the core to the outer periphery.

[0071] In a twenty-sixth aspect of the present disclosure, according to any one of the first to twenty-fifth aspects, each of the plurality of segments may satisfy at least one of the following conditions: a width condition of 1 mm to 6 mm in the winding direction; a height condition of 2 mm to 10 mm in the winding axis direction; and a separation distance condition of 0.05 mm to 1 mm in the winding direction.

[0072] In a twenty-seventh aspect of the present disclosure, according to any one of the first to twenty-sixth aspects, the plurality of segments may satisfy a separation distance condition of 0.05 mm to 1 mm in the winding direction, the separation distance being defined as the distance between the corners of two adjacent segments, and circular reinforcing portions may be formed at the corners of the adjacent segments.

[0073] In a twenty-eighth aspect of the present disclosure, according to any one of the first to twenty-seventh aspects, the plurality of segments may form a plurality of segment groups from the core to the outer periphery, and at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction of the segments belonging to the same segment group may be the same as each other.

[0074] In a twenty-ninth aspect of the present disclosure, according to the twenty-eighth aspect, when three segment groups that are continuously adjacent to each other in the radial direction of the electrode assembly have widths W1, W2, and W3 in the winding direction, respectively, a combination of segment groups including W3 / W2 < W2 / W1 may be included.

[0075] In a thirtieth aspect of the present disclosure, according to the twenty-eighth or twenty-ninth aspect, the segments belonging to the same segment group are configured such that at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction may increase step by step from the core to the outer periphery in the winding direction.

[0076] In a thirty-first aspect of the present disclosure, according to any one of the twenty-eighth to thirtieth aspects, at least some of the plurality of segment groups may be provided at the same winding turn of the electrode assembly.

[0077] In the thirty-second aspect of the present disclosure, according to any one of the sixth aspect to the thirty-first aspect, the uncoated portion on the core side may not have a segmented structure of the uncoated portion.

[0078] In the thirty-third aspect of the present disclosure, according to any one of the sixth aspect to the thirty-second aspect, the uncoated portion on the periphery may not have a segmented structure of the uncoated portion.

[0079] In the thirty-fourth aspect of the present disclosure, according to any one of the first aspect to the thirty-third aspect, a plurality of segments may be bent toward the core in the radial direction, and the plurality of bent segments may overlap with the segments closer to the core to form multiple layers.

[0080] In the thirty-fifth aspect of the present disclosure, according to the thirty-fourth aspect, the electrode assembly may have a cavity formed in the core, and the cavity may not be closed by the plurality of segments bent toward the core.

[0081] In the thirty-sixth aspect of the present disclosure, according to any one of the sixth aspect to the thirty-fifth aspect, the radial length (R) of the uncoated portion on the core side and the height (H) of the innermost segment of the intermediate uncoated portion may satisfy the formula H ≤ R.

[0082] In the thirty-seventh aspect of the present disclosure, according to any one of the sixth aspect to the thirty-sixth aspect, the uncoated portion on the periphery may be configured to have a height decreasing from the core to the outer periphery.

[0083] In the thirty-eighth aspect of the present disclosure, according to the thirty-seventh aspect, the height of the uncoated portion on the periphery may gradually decrease along the winding direction.

[0084] In the thirty-ninth aspect of the present disclosure, according to any one of the sixth aspect to the thirty-eighth aspect, the uncoated portion on the periphery and the intermediate uncoated portion may be divided into a plurality of segments.

[0085] And the plurality of segments included in the uncoated portion on the periphery are configured such that at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction may be larger than that of the plurality of segments included in the intermediate uncoated portion.

[0086] In the fortieth aspect of the present disclosure, according to any one of the first aspect to the thirty-ninth aspect, the separator may include: a porous polymer substrate; and a porous coating located on at least one surface of the porous polymer substrate and containing inorganic particles and a binder polymer.

[0087] In the forty-first aspect of the present disclosure, according to the fortieth aspect, the inorganic particles may include inorganic particles having a hydrophilic surface.

[0088] The forty-second aspect of the present disclosure relates to a cylindrical battery cell, which includes: an electrode assembly according to any one of the sixth aspect to the forty-first aspect;

[0089] a battery can configured to accommodate the electrode assembly and electrically connected to one of the first electrode plate and the second electrode plate to have a first polarity;

[0090] a seal configured to seal the open end of the battery can; and

[0091] a terminal electrically connected to the other of the first electrode plate and the second electrode plate to have a second polarity and configured to have a surface exposed to the outside,

[0092] wherein the separator includes: a porous polymer substrate; and a porous coating located on two surfaces of the porous polymer substrate and containing inorganic particles and a binder polymer.

[0093] In the forty-third aspect of the present disclosure, according to the forty-second aspect, the uncoated portion as the second part may include a core-side uncoated portion adjacent to the core of the electrode assembly, a peripheral uncoated portion adjacent to the outer periphery of the electrode assembly, and an intermediate uncoated portion interposed between the core-side uncoated portion and the peripheral uncoated portion.

[0094] In the forty-fourth aspect of the present disclosure, according to the forty-third aspect, in the winding axis direction, the peripheral uncoated portion may have a relatively smaller height than the intermediate uncoated portion.

[0095] The battery can may include a curled portion formed at an end adjacent to the open end thereof for press-fitting inward.

[0096] And the inner periphery of the top edge of the curled portion facing the electrode assembly may be spaced apart from the peripheral uncoated portion at a predetermined interval.

[0097] In the forty-fifth aspect of the present disclosure, according to the forty-fourth aspect, the press-fitting depth (D1) of the curled portion and the distance (D2) from the inner periphery of the battery can to the boundary point between the peripheral uncoated portion and the intermediate uncoated portion may satisfy the formula D1 ≤ D2.

[0098] In the forty-sixth aspect of the present disclosure, according to the forty-fourth aspect or the forty-fifth aspect, the cylindrical battery cell may further include: a current collector plate electrically connected to the intermediate uncoated portion;

[0099] and an insulator configured to cover the current collector plate and having an edge inserted and fixed between the inner periphery of the curled portion and the current collector plate.

[0100] In the forty-seventh aspect of the present disclosure, according to the forty-sixth aspect, the outermost diameter of the current collector plate and the middle uncoated portion may be smaller than the minimum inner diameter of the inner circumference of the crimped portion, and the diameter of the current collector plate may be equal to or greater than the outermost diameter of the middle uncoated portion.

[0101] In the forty-eighth aspect of the present disclosure, according to the forty-sixth aspect or the forty-seventh aspect, the current collector plate may be positioned higher than the bottom end of the crimped portion.

[0102] In the forty-ninth aspect of the present disclosure, according to any one of the forty-third aspect to the forty-eighth aspect, the segments in at least a partial region of the middle uncoated portion may be bent from the outer periphery toward the core portion.

[0103] The electrode assembly may have a cavity formed in the core portion, and the cavity may not be closed by the bent structure of the middle uncoated portion.

[0104] In the fiftieth aspect of the present disclosure, according to the forty-ninth aspect, the middle uncoated portion may include a plurality of segments.

[0105] And the radial length (R) of the core-side uncoated portion and the height (H) of the innermost segment of the middle uncoated portion may satisfy the formula H ≤ R.

[0106] In the fifty-first aspect of the present disclosure, according to the fiftieth aspect, each of the plurality of segments may have a rectangular structure, a trapezoidal structure, a triangular structure, an equilateral quadrilateral structure, a semi-circular structure, or a semi-elliptical structure.

[0107] In the fifty-second aspect of the present disclosure, according to the fiftieth aspect or the fifty-first aspect, each of the plurality of segments may satisfy at least one of the following conditions: a width condition of 1 mm to 6 mm in the winding direction; a height condition of 2 mm to 10 mm in the winding axis direction; and a separation distance condition of 0.05 mm to 1 mm in the winding direction.

[0108] In the fifty-third aspect of the present disclosure, according to any one of the forty-second aspect to the fifty-second aspect, a gap may be provided between the cut valley portion of the segment of the electrode assembly and the active material layer.

[0109] In the fifty-fourth aspect of the present disclosure, according to the fifty-third aspect, the gap may be 0.2 mm to 4 mm.

[0110] In the fifty-fifth aspect of the present disclosure, according to any one of the fiftieth aspect to the fifty-fourth aspect, the plurality of segments may form a plurality of segment groups.

[0111] The segments belonging to the same segment group may be the same as each other in at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction.

[0112] And at least one of the plurality of segment groups can form the same winding turn of the electrode assembly.

[0113] In a fifty-sixth aspect of the present disclosure, according to any one of the fiftieth aspect to the fifty-fifth aspect, a plurality of segments can form a plurality of segment groups.

[0114] And when three segment groups that are continuously adjacent to each other in the radial direction of the electrode assembly have widths W1, W2, and W3 in the winding direction, respectively, a combination of segment groups in which W3 / W2 is less than W2 / W1 can be included.

[0115] In a fifty-seventh aspect of the present disclosure, according to any one of the forty-second aspect to the fifty-sixth aspect, the sealing body can include a cover plate configured to seal the open end of the battery can, and a gasket configured to surround the edge of the cover plate and press against the top end of the battery can, and the terminal having the second polarity can be the cover plate.

[0116] In a fifty-eighth aspect of the present disclosure, according to any one of the forty-second aspect to the fifty-seventh aspect, the cylindrical battery cell can further include: a current collector plate that is electrically connected to the uncoated portion of the second electrode plate having the first polarity and has an edge at least partially coupled to the side wall of the battery can.

[0117] The sealing body can include a cover plate without a polarity and a gasket configured to surround the edge of the cover plate and press against the top end of the battery can.

[0118] And the battery can can include a riveted terminal that is installed to be insulated in a perforation formed in the central portion of the closed surface of the battery can and is electrically connected to the first electrode plate to have the second polarity.

[0119] A fifty-ninth aspect of the present disclosure relates to a battery pack that includes at least one battery cell according to any one of the forty-second aspect to the fifty-eighth aspect.

[0120] A sixtieth aspect of the present disclosure relates to a vehicle that includes at least one battery pack according to the fifty-ninth aspect.

[0121] Advantageous Effects

[0122] According to an embodiment of the present disclosure, since the uncoated portions protruding from the upper and lower portions of the electrode assembly itself serve as electrode joints, the internal resistance of the battery cell can be reduced and the energy density can be increased.

[0123] According to another embodiment of the present disclosure, since the structure of the uncoated portion of the electrode assembly is improved, during the process of forming the curled portion of the battery can, the electrode assembly does not interfere with the inner circumference of the battery can, so that a short circuit in the cylindrical battery cell caused by partial deformation of the electrode assembly can be prevented.

[0124] According to still another embodiment of the present disclosure, since the structure of the uncoated portion of the electrode assembly is improved, the uncoated portion can be prevented from being torn when the uncoated portion is bent, and the number of overlapping layers of the uncoated portion is sufficiently increased, thereby improving the welding strength.

[0125] According to still another embodiment of the present disclosure, since the structure of the uncoated portion adjacent to the core portion of the electrode assembly is improved, when the uncoated portion is bent, the cavity in the core portion of the electrode assembly can be prevented from being blocked. Therefore, the electrolyte injection process and the processes of welding the battery can (or riveting the terminal) and the current collector plate can be easily performed.

[0126] According to still another embodiment of the present disclosure, a cylindrical battery cell, a battery pack including the cylindrical battery cell, and a vehicle can be provided. The structure of the cylindrical battery cell has a low internal resistance, prevents internal short circuits, and improves the welding strength between the current collector plate and the uncoated portion.

[0127] In addition, the present disclosure can have several other effects, and these effects will be described in each embodiment, or any description of effects that can be easily inferred by those skilled in the art will be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0128] The drawings illustrate preferred embodiments of the present disclosure and are used together with the foregoing disclosure to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the drawings.

[0129] Figure 1 is a plan view showing the structure of an electrode plate for manufacturing a conventional seamless cylindrical battery cell.

[0130] Figure 2 is a view showing the winding process of an electrode plate of a conventional seamless cylindrical battery cell.

[0131] Figure 3 is a view showing the process of welding a current collector plate to the curved surface of the uncoated portion of a conventional seamless cylindrical battery cell.

[0132] Figure 4 is a plan view showing the structure of an electrode plate according to a first embodiment of the present disclosure.

[0133] Figure 5 is a plan view showing the structure of an electrode plate according to a second embodiment of the present disclosure.

[0134] Figure 6 is a plan view showing the structure of an electrode plate according to a third embodiment of the present disclosure.

[0135] Figure 7a is a plan view showing the structure of an electrode plate according to a fourth embodiment of the present disclosure, and Figure 7b and Figure 7c is an enlarged view more specifically showing a segment portion.

[0136] Figure 8 is a view showing the definition of the width, height, and separation distance of a segment according to an embodiment of the present disclosure.

[0137] Figure 9a is a plan view showing the structure of an electrode plate according to a fifth embodiment of the present disclosure, and Figure 9b and Figure 9c is an enlarged view more specifically showing a segment portion.

[0138] Figure 10 is a view showing the definition of the width, height, and separation distance of a segment according to another embodiment of the present disclosure.

[0139] Figure 11 is a cross-sectional view of a wound-core type electrode assembly taken along the Y-axis direction (winding axis direction), in which the electrode plate of the first embodiment is applied to a first electrode plate (positive electrode plate) and a second electrode plate (negative electrode plate).

[0140] Figure 12 is a cross-sectional view of a wound-core type electrode assembly taken along the Y-axis direction (winding axis direction), in which the electrode plate of the second embodiment is applied to a first electrode plate (positive electrode plate) and a second electrode plate (negative electrode plate).

[0141] Figure 13 is a cross-sectional view of a wound-core type electrode assembly taken along the Y-axis direction (winding axis direction), in which one of the electrode plates of the third to fifth embodiments (variations thereof) is applied to a first electrode plate (positive electrode plate) and a second electrode plate (negative electrode plate).

[0142] Figure 14 is a cross-sectional view of an electrode assembly according to another embodiment of the present disclosure taken along the Y-axis direction (winding axis direction).

[0143] Figure 15 is a cross-sectional view of an electrode assembly according to another embodiment of the present disclosure taken along the Y-axis direction (winding axis direction).

[0144] Figure 16It is a cross-sectional view of an electrode assembly according to another embodiment of the present disclosure taken along the Y-axis direction (winding axis direction).

[0145] Figure 17 It is a cross-sectional view of a cylindrical battery cell according to an embodiment of the present disclosure taken along the Y-axis direction.

[0146] Figure 18 It is a cross-sectional view of a cylindrical battery cell according to another embodiment of the present disclosure taken along the Y-axis direction.

[0147] Figure 19 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis direction.

[0148] Figure 20 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis.

[0149] Figure 21 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis.

[0150] Figure 22 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis.

[0151] Figure 23 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis.

[0152] Figure 24 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis.

[0153] Figure 25 It is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present disclosure taken along the Y-axis.

[0154] Figure 26 It is a schematic view showing a battery pack according to an embodiment of the present disclosure.

[0155] Figure 27 It is a schematic view showing a vehicle including a battery pack according to an embodiment of the present disclosure.

[0156] Figure 28 and Figure 29 show the electrolyte impregnation amounts at each electrode position in the positive electrode and the negative electrode according to Comparative Example A-1.

[0157] Figure 30 and Figure 31Shows the amount of electrolyte impregnation at each electrode position in the positive and negative electrodes according to Example A-1.

[0158] Figure 32 and Figure 33 Shows the amount of electrolyte impregnation at each electrode position in the positive and negative electrodes according to Example A-2.

[0159] Figure 34 and Figure 35 Shows the amount of electrolyte impregnation at each electrode position in the positive and negative electrodes according to Example B-1.

[0160] Figure 36 and Figure 37 Shows the amount of electrolyte impregnation at each electrode position in the positive and negative electrodes according to Example B-2.

[0161] Figure 38 and Figure 39 Shows the amount of electrolyte impregnation at each electrode position in the positive and negative electrodes according to Example B-3.

[0162] Figure 40 Shows each position where impregnation samples are collected in each comparative example and each example.

[0163] Figure 41 Contrastingly shows the widths of the electrode active material portions of the positive electrode and the negative electrode in the electrode assembly according to an embodiment of the present disclosure.

[0164] Figure 42 Schematically shows the bent shape of the segments of the uncoated portion in the electrode assembly according to an embodiment of the present disclosure.

[0165] Figure 43 Is a schematic cross-sectional view showing the bent surface region formed by bending the segment toward the core of the electrode assembly.

[0166] Figure 44 Is a schematic top view showing the electrode assembly formed with the bent surface region.

[0167] Figure 45 Is a graph showing the result of counting the number of segment laminations in the radial direction in the bent surface region of the positive electrode formed on the electrode assembly according to the embodiment. Detailed Description

[0168] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to the general dictionary meaning, but should be interpreted based on the meanings and concepts corresponding to the technical aspects of the present disclosure on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation.

[0169] Therefore, the description presented herein is a preferred example for illustrative purposes only and is not intended to limit the scope of the present disclosure. Thus, it should be understood that other equivalents and modifications can be made without departing from the scope of the present disclosure.

[0170] In addition, to assist in understanding the invention, in the drawings, some components may not be drawn to scale, but their dimensions may be exaggerated. In addition, in different embodiments, the same reference numerals may be assigned to the same components.

[0171] For ease of description, in this specification, the direction along the length direction of the winding axis of the electrode assembly wound in a core shape is referred to as the axial direction (Y). In addition, the direction around the winding axis is referred to as the circumferential direction or the peripheral direction (X). In addition, the direction approaching or departing from the winding axis is referred to as the radial direction or the radius direction (Z). Among them, the direction approaching the winding axis is referred to as the centripetal direction, and the direction departing from the winding axis is referred to as the centrifugal direction.

[0172] First, an electrode assembly according to an embodiment of the present disclosure will be described.

[0173] The electrode assembly includes a first electrode plate, a second electrode plate, and a separator located between the first electrode plate and the second electrode plate, and the first electrode plate, the second electrode plate, and the separator are wound together around an axis in one direction to have a plurality of winding turns. In addition, each of the first electrode plate and the second electrode plate includes a first side surface and a second side surface opposite to the first side surface in the direction of the axis.

[0174] In an embodiment of the present disclosure, any one of the first electrode plate and the second electrode plate is a positive electrode plate, and the other is a negative electrode plate.

[0175] According to an embodiment of the present disclosure, each of the first electrode plate and the second electrode plate may have a rectangular sheet shape. In addition, each of the first electrode plate and the second electrode plate may have a sheet shape with an aspect ratio greater than 1. At this time, each end of each electrode plate in the width direction corresponds to the first side surface and the second side surface.

[0176] Figure 4 is a plan view showing the structure of the electrode plate 40 according to the first embodiment of the present disclosure.

[0177] Referring to Figure 4 , the second side surface is the side surface formed along the lowermost end portion of the electrode active material portion 42 in the winding axis direction Y, and the first side surface is the side surface formed along the uppermost end portion of the uncoated portion 43 in the winding axis direction Y.

[0178] Each of the first electrode plate and the second electrode plate independently includes a first portion, which is an electrode active material portion coated with an electrode active material on at least one surface or two surfaces. The first portion extends a predetermined length (width) from the second side surface in the direction of the first side surface. Figure 4 The electrode shape before winding the electrode assembly is shown. Referring thereto, the electrode active material portion may have a constant width along the axial direction from the second side surface to the portion where the uncoated portion starts over the entire length of the electrode plate.

[0179] The second portion is an uncoated portion without an electrode active material coated thereon. The second portion is provided to form an electrode joint, and the second portion extends from the first side surface to the active material of the first portion in the direction of the second side surface.

[0180] In one embodiment of the present disclosure, at least a part of the uncoated portion in accordance with the winding direction is divided into a plurality of segments by grooving to a predetermined depth.

[0181] The segment has a first end corresponding to the first side surface. In one embodiment of the present disclosure, all or at least a part of the segments may be radially bent at the bending point in the radial direction (toward the winding center) of the electrode assembly or in the direction opposite to the radial direction with respect to the axis, and the bending point is a predetermined point below the first end in each segment. At the same time, according to a specific embodiment of the present disclosure, the bending point may be a point between the first end and the baseline. At the same time, according to the present disclosure, the baseline is a virtual straight line extending in the winding direction (X) and having a height corresponding to the notch valley of the grooving.

[0182] As described above, in the current collector of the present disclosure, the uncoated portion includes a plurality of segments, and in this case, the separator may be positioned such that the notch valley of the grooving between the segments is not exposed by being covered with the separator, or when the separator is located below the baseline, the interval between the end of the separator and the baseline may be limited within a predetermined range. The position of the separator will be described in more detail below.

[0183] In the present disclosure, each of the segments may have a different height of the first end, each of the groovings may have a different shape, and the height of the notch valley of the grooving may be different. That is, the shapes and sizes of the segments themselves and the shapes and sizes of the groovings themselves may be different from each other.

[0184] At the same time, the height of the segment may be defined as the length (C2, D2) from the notch valley of the grooving to the first end in the axial direction, and the grooving may define each of the segments. If the heights of the notch valleys of the groovings located on both sides with respect to the segment are different, the height of the segment may be defined as the axial distance from the point corresponding to the average height of the notch valleys of the groovings on both sides to the first end of the segment.

[0185] Each of the first electrode plate and the second electrode plate may independently include a current collector and an electrode active material layer. The current collector is a conductive thin film, and the electrode active material layer is disposed on one or both surfaces of the current collector. The active material layer forms the first part of each electrode.

[0186] The first electrode plate and the second electrode plate having a sheet-like shape may have an aspect ratio greater than 1. In this case, the uncoated portion is disposed along the winding direction at the long side of the electrode. At least a part of the uncoated area itself serves as an electrode terminal.

[0187] According to an embodiment of the present disclosure, the uncoated portion includes a core-side uncoated portion adjacent to the core of the electrode assembly, a peripheral uncoated portion adjacent to the outer peripheral surface of the electrode assembly, and an intermediate uncoated portion interposed between the core-side uncoated portion and the peripheral uncoated portion.

[0188] Preferably, at least one of the core-side uncoated portion and the peripheral uncoated portion has a relatively smaller height than the intermediate uncoated portion.

[0189] Meanwhile, for ease of explanation, the term "height" refers to the length (distance) from a specific position in the winding direction (X) to the first end. In the present disclosure, when describing the height of the uncoated portion / notch valley portion, the relative value of the height measured at different positions in the winding direction rather than the absolute value of the height of the uncoated portion / notch valley portion is meaningful. Therefore, when measuring the height of the uncoated portion / notch valley portion, the specification of the line (zero point) used as a standard for measuring the height will be omitted. In an embodiment of the present disclosure, the height of the uncoated portion may be a relative distance at a specific point based on an arbitrary vertical line with respect to the winding axis direction. For example, the line (zero point) used as a reference for measuring the height may be the second side surface.

[0190] On the other hand, more specifically, regarding the height of the uncoated portion, in the section where no segment is formed, it refers to the distance to the first side surface, and in the section where a segment is formed, the first side surface refers to the position corresponding to the first end of the segment. In addition, when measuring the height of the uncoated portion in the section where a segment is formed, the portion constituting the cut groove between the segments is not considered.

[0191] In addition, the height of the notch valley portion is measured based on the portion having the lowest height in the cut groove.

[0192] Refer to Figure 4, the electrode plate 40 of the first embodiment includes a current collector 41 made of a metal foil and an electrode active material portion 42. The metal foil can be aluminum or copper and is appropriately selected according to the polarity of the electrode plate 40. The active material portion 42 is formed on at least one surface of the current collector 41, and an uncoated portion 43 is provided at a long side end of the current collector along the winding direction X. The uncoated portion 43 is an area not coated with the active material. An insulating coating 44 can be formed at the boundary between the electrode active material portion 42 and the uncoated portion 43. The insulating coating 44 is formed such that at least a part of it overlaps with the boundary between the active material portion 42 and the uncoated portion 43. The insulating coating 44 can include a polymer resin and can include an inorganic material such as Al 2 O 3 .

[0193] The uncoated portion 43 includes a core-side uncoated portion B1 adjacent to the core side of the electrode assembly, a peripheral uncoated portion B3 adjacent to the outer peripheral side of the electrode assembly, and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the peripheral uncoated portion B3.

[0194] When the electrode plate 40 is wound into a core-type electrode assembly, the core-side uncoated portion B1, the peripheral uncoated portion B3, and the intermediate uncoated portion B3 can be respectively defined as the uncoated portion of the area adjacent to the core, the uncoated portion of the area adjacent to the outer periphery, and the uncoated portion of the remaining area other than the above areas. The boundary of B1 / B2 can be appropriately defined as the point where the height (or variation pattern) of the uncoated portion significantly changes from the core of the electrode assembly to the outer periphery, or a specific percentage (%) point based on the radius of the electrode assembly (e.g., 5% point, 10% point, 15% point, etc.) of the radius. The boundary of B2 / B3 is the point where the height (or variation pattern) of the uncoated portion significantly changes from the outer periphery of the electrode assembly to the core, or a specific percentage (%) point based on the radius of the electrode assembly (e.g., 85% point, 90% point, 95% point, etc.). When the boundaries of B1 / B2 and B2 / B3 are specified, the intermediate uncoated portion B2 can be automatically specified. If only the boundary of B1 / B2 is specified, the boundary of B2 / B3 can be appropriately selected at a point near the outer periphery of the electrode assembly. Conversely, if only the boundary of B2 / B3 is specified, the boundary of B1 / B2 can be appropriately selected at a point near the core of the electrode assembly. In the first embodiment, the height of the uncoated portion 43 is not constant, and there is a relative difference along the winding direction X. That is, the height (length in the Y-axis direction) of the peripheral uncoated portion B3 is relatively smaller than the heights of the core-side uncoated portion B1 and the intermediate uncoated portion B2.

[0195] Meanwhile, in the present disclosure, in the electrode plate, the width of the electrode active material portion located at the short side of the current collector may be 50 mm to 120 mm, and the length of the electrode active material portion located at the long side of the current collector may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the electrode active material portion may be 1.0% to 4.0%.

[0196] Figure 5 is a plan view showing the structure of the electrode plate 45 according to the second embodiment of the present disclosure.

[0197] Referring to Figure 5 , the electrode plate 45 of the second embodiment is different from the electrode plate of the first embodiment only in that the height of the peripheral uncoated portion B3 gradually decreases toward the outer periphery, while other configurations are basically the same.

[0198] In one variant, the peripheral uncoated portion B3 may be transformed into a stepped shape with a gradually decreasing height (see the dashed line). In one embodiment of the present disclosure, in the electrode according to the second embodiment, at least one region of the uncoated portion is divided into a plurality of segments by a cut groove (not shown) having a predetermined depth.

[0199] Figure 6 is a plan view showing the structure of the electrode plate 50 according to the third embodiment of the present disclosure.

[0200] Referring to Figure 6 , in the electrode plate 50 of the third embodiment, the heights of the core-side uncoated portion B1 and the peripheral uncoated portion B3 are relatively smaller than the height of the intermediate uncoated portion B2. In addition, the heights of the core-side uncoated portion B1 and the peripheral uncoated portion B3 may be the same or different from each other.

[0201] Preferably, the height of the intermediate uncoated portion B2 may have a stepped shape that gradually increases from the core to the outer periphery.

[0202] Patterns 1 to 7 classify the intermediate uncoated portion B2 based on the position where the height of the uncoated portion 43 changes. Preferably, the number of 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 disperse stress as much as possible during the bending process of the uncoated portion 43. Stress dispersion is to prevent the uncoated portion 43 from tearing.

[0203] The width (d B1 ) of the core-side uncoated portion B1 is designed by applying the condition that when the pattern of the intermediate uncoated portion B2 bends toward the core, it does not cover the cavity in the core of the electrode assembly.

[0204] In one embodiment of the present disclosure, in the electrode according to the third embodiment, at least one region of the uncoated portions of Patterns 1 to 7 is divided into a plurality of segments by a grooved cut (not shown) having a predetermined depth.

[0205] In one example, the width (d B1 ) of the uncoated portion B1 on the core side can increase proportionally to the length from the baseline to the first end of Pattern 1 or the height of the segment of Pattern 1.

[0206] In a specific example, when the electrode plate 60 is used to manufacture an electrode assembly for a cylindrical battery cell with a form factor of 46800, according to the diameter of the core of the electrode assembly, the width (d B1 ) of the uncoated portion B1 on the core side is set to 180 mm to 350 mm.

[0207] In one embodiment, the width of each pattern can be designed to form the same winding turn of the electrode assembly.

[0208] In a variant, the height of the intermediate uncoated portion B2 can have a stepped shape that increases from the core to the outer periphery and then decreases.

[0209] In another variant, the peripheral uncoated portion B3 can be modified to have the same structure as the second embodiment.

[0210] In yet another variant, the pattern structure applied to the intermediate uncoated portion B2 can be extended to the peripheral uncoated portion B3 (see the dashed line).

[0211] Figure 7a is a plan view showing the structure of the electrode plate 60 according to the fourth embodiment of the present disclosure. Figure 7a Shows the formation of segments throughout the intermediate uncoated portion.

[0212] Referring to Figure 7a , in the electrode plate 60 of the fourth embodiment, the heights of the uncoated portion B1 on the core side and the peripheral uncoated portion B3 are relatively smaller than the height of the intermediate uncoated portion B2. In addition, the heights of the uncoated portion B1 on the core side and the peripheral uncoated portion B3 can be the same or different.

[0213] Preferably, at least a partial region of the intermediate uncoated portion B2 can include a plurality of segments 61. The heights of the plurality of segments 61 can gradually increase from the core to the outer periphery.

[0214] In the present disclosure, all or at least a part of the segment is bent along the radial direction (winding center direction) of the electrode assembly or in a direction opposite to the radial direction. The segment may be bent at a position spaced a predetermined height upward from the notch valley (bottom of the cut groove). According to the present disclosure, the bending point is the point at which the inclination angle of the tangent line in the portion generated by bending the segment along the direction of the winding center by using an external force starts to be less than 45°. The inclination angle of the tangent line refers to the angle between the tangent line at the bending point and the plane perpendicular to the winding axis of the electrode assembly. At the same time, the bending line is a line parallel to the baseline and includes the bending point.

[0215] At the same time, in the present disclosure, the heights of the segments may be equal to or different from each other.

[0216] If the heights of the notch valleys are equal, the baseline is a virtual straight line extending along the winding direction (X) and having a height corresponding to the notch valley of the cut groove.

[0217] If the notch valleys of most of the cut grooves are located at a specific height and only the notch valleys of some of the cut grooves have a height different from the specific height, the baseline is determined as the height corresponding to the specific height. For example, when 50% or more of the notch valleys are located at a specific height, the baseline may be determined as the height corresponding to the height of the notch valley. Alternatively, the baseline may be determined based on the height of the notch valley of the cut groove that occupies the maximum length along the winding direction. For example, if about 2 / 3 of the total length occupied by the notch valley of the cut groove along the winding direction has a first height and the height of the notch valley of the cut groove corresponding to the remaining 1 / 3 of the total length occupied by the notch valley of the cut groove along the winding direction is different from the first height, the baseline may be defined as being located at a position corresponding to the first height.

[0218] If the heights of the notch valleys of the cut grooves are not concentrated at a specific height (less than 50% of the most concentrated cut grooves), the baseline may be determined as the average height of the heights of the bottoms of the cut grooves. For example, if the length occupied by the height x of the notch valley of the cut groove along the winding direction is 30%, the length occupied by the height y of the notch valley of the cut groove along the winding direction is 30%, and the length occupied by the height z of the notch valley of the cut groove along the winding direction is 40%, the baseline may be at the position of x*0.3 + y*0.3 + z*0.4. The height of the notch valley may be the relative distance at a specific point based on any vertical line with respect to the winding axis direction. For example, the height of the notch valley may be based on the distance from the second side surface to the notch valley.

[0219] In one embodiment of the present disclosure, the bending point may be located about 2 mm to 3 mm above the notch valley and may be arranged parallel to the baseline.

[0220] Meanwhile, in one embodiment of the present disclosure, the baseline may be the same as or different from a line extending in the winding direction (Y) from the point having the minimum height in the uncoated portion. In one embodiment, the baseline may be the same as a line extending in the winding direction from the point having the minimum height in the uncoated portion.

[0221] The segment 61 can be formed by laser grooving. The segment 61 can be formed by known metal foil cutting processes such as ultrasonic cutting or stamping.

[0222] In the fourth embodiment, in order to prevent the active material portion 42 and / or the insulating coating 44 from being damaged during the bending of the uncoated portion 43, it is preferable to provide a gap with a predetermined interval distance between the incision valley portion between the segments 61 and the active material portion 42. This is because when the uncoated portion 43 is bent, stress concentration occurs near the bottom of the cutting line. The gap is preferably 0.2 mm to 4 mm. If the gap is adjusted within the corresponding numerical range, the active material portion 42 and / or the insulating coating 44 can be prevented from being damaged by the stress generated during the bending of the uncoated portion 43 near the bottom of the cutting line. In addition, the gap can prevent the active material portion 42 and / or the insulating coating 44 from being damaged due to the tolerance during the grooving or cutting of the segment 61. Preferably, when the electrode plate 60 is wound into an electrode assembly, at least a part of the insulating coating 44 can be exposed outside the separator. In this case, when the segment 61 is bent, the insulating coating 44 can support the incision valley portion.

[0223] The gap between the incision valley portion of the segment and the active material layer can preferably be 1.0 mm or more. This may be more effective when the corresponding electrode is a negative electrode.

[0224] The gap between the incision valley portion of the segment and the active material layer can be more preferably 2.0 mm or more. This may be more effective when the corresponding electrode is a positive electrode.

[0225] A gap smaller than the above range may not be sufficient to exhibit the above anti-damage effect, and a gap larger than the above range may only result in a reduction in the electrode capacity without improving the anti-damage effect.

[0226] The boundary region between the uncoated portion area without the active material layer and the area coated with the active material layer can be covered by an insulating layer, and at this time, a predetermined gap can also be provided between the incision valley portion of the segment and the insulating layer.

[0227] This gap can be 0.2 mm to 1.5 mm.

[0228] A gap smaller than the above range may not be sufficient to exhibit the above anti-damage effect, and a gap larger than the above range may cause a reduction in the segment bending support effect of the insulating coating without improving the anti-damage effect.

[0229] A plurality of segments 61 may form a plurality of segment groups from the core to the outer periphery. The widths, heights, and separation distances of the segments belonging to the same segment group may be substantially the same.

[0230] Meanwhile, in the present disclosure, the width of the electrode active material portion of the positive electrode plate in the electrode assembly may be equal to or less than the width of the electrode active material portion of the negative electrode plate. Further, based on the width direction, the width of the electrode active material portion of the positive electrode plate may be set within the width of the electrode active material portion of the negative electrode plate.

[0231] Figure 41 is a schematic view showing a part of a cross-section of the wound electrode assembly. Refer to Figure 41 , the positive electrode plate 11 and the negative electrode plate 12 are laminated, and a separator 13 is interposed therebetween. Here, 11cc represents the positive electrode current collector, 12cc represents the negative electrode current collector, and 11ea and 12ea represent the electrode active material portions of the positive electrode plate and the negative electrode plate, respectively. Referring thereto, the width of the electrode active material portion of the positive electrode plate is smaller than the width of the electrode active material portion of the negative electrode plate, and is set within the width of the electrode active material portion of the negative electrode plate. Meanwhile, the ends of the current collectors 11a and 12a include the segments as described above and are bent as Figure 42 shown. As described above, the empty space generated due to the shorter width of the electrode active material portion of the positive electrode plate than that of the negative electrode plate may be set as a channel for the electrolyte inside the wound core electrode assembly, which is beneficial to the impregnation of the electrolyte.

[0232] Meanwhile, each electrode active material portion may include a sliding portion on at least one of the two lateral ends, which has a reduced thickness compared to the central region. Figure 42 shows a specific embodiment of the present disclosure, and referring to Figure 42 , the sliding portion may be formed at one end of the two ends in contact with the uncoated portion. The sliding portion may be formed on both the positive electrode and the negative electrode or any one of them, and when the sliding portion is formed at one end of both the positive electrode and the negative electrode, the sliding portions may be placed in opposite directions.

[0233] Further, in a specific embodiment of the present disclosure, the sliding portion may be covered by an insulating layer. As described above, when the insulating layer is formed on the uncoated portion, the insulating layer may extend to the sliding portion.

[0234] A sliding portion can be formed by a sliding phenomenon that occurs near the boundary between the electrode active material portion and the uncoated portion when the electrode active material is coated on the electrode current collector. The sliding phenomenon refers to a phenomenon in which, due to the spreading of the slurry containing the electrode active material, less electrode active material is coated in the slurry coating boundary region compared to regions other than the slurry coating boundary region, such that the slurry in the coating boundary region has a substantially inclined shape. Due to this sliding phenomenon, a sliding portion having a substantially downward inclined surface in the direction from the coated portion toward the uncoated portion can be formed at the edge of the electrode active material portion. The insulating layer is not particularly limited as long as it contains an insulating material, and any insulating polymer material or inorganic material can be used without limitation.

[0235] In Figure 7a and Figure 9a a separator SP facing the active material portion 42 and / or the insulating coating 44 of the electrode plate 60 according to the fourth embodiment can be provided to form an electrode assembly.

[0236] Referring to Figure 7b 、 Figure 7c 、 Figure 8 、 Figure 9b and Figure 9c points in the electrode assembly of the present disclosure will be described at which the end of the separator is located on the uncoated portion of the electrode plate.

[0237] When describing embodiments of the present disclosure with reference to the drawings, the uncoated portion may include a plurality of segments, and the depths of the cut valleys between the plurality of segments may be the same. In this case, a line extending from a point corresponding to the depth of the cut valley is used as a baseline.

[0238] In this case, the baseline may be a line connecting the minimum height among the core-side uncoated portion, the peripheral uncoated portion, and the intermediate uncoated portion to both ends of the uncoated portion.

[0239] As the end of the separator in the width direction deviates to the outside of the core (i.e., in the outer direction of the electrode assembly), the welding characteristics are adversely affected. In addition, as the end of the separator in the width direction moves to the inside of the core (i.e., in the inner direction of the electrode assembly), the risk of short circuit between the positive electrode and the negative electrode increases.

[0240] Therefore, in the present disclosure, the end SL of the separator in the width direction is located within a predetermined interval based on the baseline in the outer direction of the electrode assembly, or the end of the separator in the width direction is located within a predetermined interval based on the baseline in the inner direction of the electrode assembly. Here, the outer direction of the electrode assembly refers to the direction toward the uncoated portion of the active material layer of the electrode (pointing to the first side), and the inner direction refers to the direction opposite to the outer direction (pointing to the second side).

[0241] In a specific embodiment of the present disclosure, when the segment with the minimum height among multiple segments is the minimum bending segment, the end of the separator in the width direction of the separator may be located at a position less than 50% of the height (Ha) based on the baseline of the minimum bending segment in the outer direction of the electrode assembly, or within 40%, 30%, 20%, or 10% of this height. Preferably, the end of the separator in the width direction of the separator may be located within 30% of the height (Ha) based on the baseline of the minimum bending segment in the outer direction of the electrode assembly. At this time, the separator may be arranged such that the cut valley of the cut groove between the segments is covered by the separator without being exposed. If the position of the separator exceeds the above range and is positioned closer to the first end of the segment, the separator may be damaged by heat when welding the segments.

[0242] According to another embodiment, the end of the separator in the width direction may be located within 30%, 20%, or 10% of the height (Ha) based on the baseline of the minimum bending segment in the inner direction of the electrode assembly. At the same time, when the end of the separator is located below the baseline, all or at least a part of the cut valley may be exposed without being covered by the separator. When the position of the separator is arranged to exceed the above range inwardly, it is difficult to ensure insulation between the positive electrode and the negative electrode.

[0243] Furthermore, according to an embodiment of the present disclosure, by controlling the end of the separator in the width direction to be near the baseline, the electrolyte flows into the electrode assembly along the cut valley (empty space), which is beneficial for impregnation. In other words, when the segments are bent and the bent segments overlap, the movement of the electrolyte into the electrode assembly may be hindered, but when the end of the separator is positioned close to the cut valley as in the present disclosure, the electrolyte flowing into the electrode assembly can be undisturbed. Specifically, the electrolyte is injected into the electrode assembly. At this time, the electrolyte moves into the cut valley between the segments of the uncoated portion of the electrode plate in the electrode assembly, and at this time, the electrolyte is impregnated again into the valley between the segments (i.e., the end of the separator positioned near the baseline), and finally impregnated into the active material layer of the electrode. As a result, the uniformity of electrolyte impregnation in the electrode assembly increases.

[0244] Meanwhile, in another embodiment of the present disclosure, one end SL of the diaphragm may be located between the bending point and the boundary between the first part and the second part. That is to say, either end of the diaphragm may be located between the bending point and the baseline or below the baseline. More specifically, when the shortest distance between the maximum height (the highest point) in the winding axis direction and the baseline of the surface area of the electrode assembly is the height (HS) of the surface area, the end of the diaphragm in the width direction may be located within 90% of the height (HS) based on the baseline of the surface area in the outer direction or the inner direction of the electrode assembly. The surface area refers to the surface area at the top or bottom of the electrode assembly in the winding axis direction formed when the segments of the winding turns adjacent to each other in the curved segment of the electrode assembly continuously overlap in the radial direction or the direction opposite thereto.

[0245] In the present disclosure, the electrode assembly may include a surface area formed by bending a plurality of segments in the radial direction of the electrode assembly. In other words, as the segments of the winding turns adjacent to each other in the curved segment continuously overlap in the radial direction or the direction opposite thereto, a surface area is formed at the top or bottom of the electrode assembly in the winding axis direction.

[0246] In another specific embodiment of the present disclosure, the surface area may include a region with a uniform number of stacked segments where the number of stacked segments remains uniform in the radial direction and one or more regions with a decreasing number of stacked segments adjacent to the region with a uniform number of stacked segments where the number of stacked segments of the segments decreases as it moves away from the region with a uniform number of stacked segments.

[0247] That is to say, a plurality of segments are stacked in multiple layers while being bent in the radial direction of the electrode assembly to form a surface area, and the surface area may include a region with a uniform number of stacked segments where the number of stacked segments of the segments is uniform in the radial direction and a region with a decreasing number of stacked segments adjacent to the region with a uniform number of stacked segments where the number of stacked segments of the segments decreases as it moves away from the region with a uniform number of stacked segments. In one embodiment of the present disclosure, the stacked thickness of the segments in the region with a uniform number of stacked segments may be 50 μm to 875 μm.

[0248] On the one hand, the radial lengths of the region with a uniform number of stacked segments and the region with a decreasing number of stacked segments based on the center of the core of the electrode assembly may correspond to the radial length of the radial region where the winding turns including a plurality of segments are located.

[0249] On the other hand, the starting radius of the region with a uniform number of stacked segments based on the center of the core of the electrode assembly may correspond to the starting radius of the middle uncoated portion.

[0250] Preferably, the number of stacked segments of the segments in the region with a uniform number of stacked segments may be 10 to 35.

[0251] On the other hand, the ratio of the radial length of the region with a uniform number of laminations to the radial lengths of the region with a uniform number of laminations and the region with a decreasing number of laminations may be from 30% to 85%.

[0252] Here, the number of segments intersecting a virtual line parallel to the winding axis direction at any radial position in the surface region is defined as the number of segment laminations at the corresponding radial position.

[0253] Figure 43 is a schematic cross-sectional view showing a bent surface region F formed by bending a segment 61 toward the core C of the electrode assembly 80. In Figure 43 only the cross-section of the bent surface region F is shown on the left side with respect to the winding axis of the electrode assembly 80. The bent surface region F can be formed on both the top and bottom of the electrode assembly 80. Figure 44 is a perspective view from above schematically showing the electrode assembly 80 on which the bent surface region F is formed.

[0254] Referring to Figure 43 and Figure 44 , the bent surface region F has a structure in which the segments 61 are overlapped in multiple layers in the winding axis direction. The overlapping direction is the winding axis direction Y. Region ① is an uncoated portion on the core side without segments, and regions ② and ③ are regions where the winding turns including the segments 61 are located and may be intermediate uncoated portions. In addition, in region ②, the height of the segment 61 may increase toward the outer periphery, and in region ③, the height of the segment may remain uniform up to the outer periphery of the electrode assembly. In addition, the radial lengths of regions ② and ③ are variable. At the same time, the uncoated portion B3 included in at least one winding turn including the outermost winding turn may not include a segment structure. In this case, the uncoated portion B3 may not be included in region ③.

[0255] At the same time, at any radial position in regions ② and ③, the number of laminations of the segment 61 may vary according to the radial position. Preferably, the height, width, and separation distance of the segment 61 can be adjusted according to the radius of the winding turn including the segment 61 so that the number of laminations of the segment 61 can be adjusted to be suitable for the purpose at each position in the bent surface region F.

[0256] At the same time, in one embodiment of the present disclosure, in the region with a uniform number of laminations, the end of the separator is located between the lowermost surface of the lamination region and the cut valley portion. At this time, the electrolyte moves along the minute gaps between the segments by capillary action. Here, in the region with a uniform number of laminations, the end of the separator is located near the lowermost surface of the region with a uniform number of laminations. Therefore, when the electrolyte is injected, the electrolyte quickly contacts the end of the separator, thereby improving the impregnation of the electrolyte into the electrode assembly.

[0257] In addition, a region with a uniform number of layers (especially a region with a uniform number of layers where the number of layers of segments is 10 or more) can be set as a desired welding target region. The welding target region is a section to which at least a part of the current collector can be welded. If the number of predetermined stacked segments is ensured in the region with a uniform number of layers as described above, damage to the separator caused by welding can be prevented.

[0258] Referring to Figure 7a 、 Figure 7b 、 Figure 7c 、 Figure 9b or Figure 9c , the segments of Group 1 can be the minimum bending segments, and one end of the separator in the width direction is located at less than 50% or within 30% of the height Ha relative to the baseline of the minimum bending segment in the outer direction (first side direction) of the electrode assembly, or one end of the separator can be located within 30% of the height Ha relative to the baseline of the minimum bending segment in the inner direction (second side direction) of the electrode assembly. More specifically, the segments of Group 1 can be the minimum bending segments, and one end of the separator can be located within 30% of the height Ha relative to the baseline of the minimum bending segment in the outer direction (first side direction) of the electrode assembly. Referring to Figure 7b or Figure 9b , when one end of the separator is disposed above the baseline, one end of the separator is located within Hb. Here, the maximum length of Hb is less than 50% of the height (length) of the minimum bending segment. At the same time, when one end of the separator is located below DL, the maximum length of Hb is 30% of the height of the minimum bending segment.

[0259] That is to say, in the present disclosure, the segment used as a standard for arranging the separator can refer to the segment with the minimum height among the bent segments, and it is called the minimum bending segment.

[0260] In a specific embodiment of the present disclosure, the minimum bending segment can have a height of 2 mm or more, and in this case, the height of the minimum bending segment is higher than the height of the bending point. If the height of the segment is less than 2 mm, the segment may not be bent smoothly due to interference between the separator and the segment. Therefore, the minimum bending segment can be determined among the segments with a height of 2 mm or more.

[0261] According to an embodiment of the present disclosure, in the minimum bending segment, the height A from the baseline to the bending line based on the bending line can be equal to or longer than the length from the bending line to the segment height B. Alternatively, in the minimum bending segment, the height A from the baseline to the bending line based on the bending line can be equal to or shorter than the length from the bending line to the segment height B.

[0262] In addition, in one embodiment of the present disclosure, the electrode assembly may further include a segment (segment A) having a height less than the minimum bending segment. At this time, segment A is not bent. In a specific embodiment, segment A may be arranged closer to the core compared to other segments among the plurality of segments.

[0263] In one embodiment of the present disclosure, the electrode assembly may not include a segment having a height less than the minimum bending segment, and the minimum bending segment may be the minimum segment.

[0264] For example, if the height of the minimum bending segment is 5 mm, the end portion of the separator in the width direction may be within 2.5 mm or 1.5 mm based on the baseline in the outer direction of the electrode assembly, or the end portion of the separator in the width direction may be within 1.5 mm based on the baseline in the inner direction of the electrode assembly.

[0265] In another embodiment, when the height of the minimum bending segment is 6 mm, the end portion of the separator in the width direction may be within 3 mm or 1.8 mm based on the baseline in the outer direction of the electrode assembly, or the end portion of the separator in the width direction may be within 1.8 mm based on the baseline in the inner direction of the electrode assembly.

[0266] Figure 8 It is a diagram showing the definitions of the width, height, and separation distance between segments in segment 61 according to one embodiment of the present disclosure.

[0267] Referring to Figure 8 , the width (C1), height (C2), and separation distance (C3) of segment 61 are designed to prevent abnormal deformation of the uncoated portion 43 while sufficiently increasing the number of overlapping layers, so as to prevent the uncoated portion 43 from being torn during bending of the uncoated portion 43 and improve the welding strength of the uncoated portion 43. Abnormal deformation means that the portion corresponding to the baseline (C4) does not remain flat but sinks and deforms irregularly.

[0268] According to an embodiment of the present disclosure, the width (C1) of the segment 61 can be adjusted within a range of 1 mm to 6 mm. If C1 is less than 1 mm, a non-overlapping region or an empty space (gap) is generated, so that the welding strength cannot be sufficiently ensured when the segment 61 is bent toward the core. At the same time, if C1 exceeds 6 mm, when the segment 61 is bent due to the curvature of the wound electrode, the uncoated portion 43 near the baseline (DL) may be torn due to stress. In addition, the height (C2) of the segment 61 can be adjusted within a range of 2 mm to 10 mm. If C2 is less than 2 mm, the segment 61 may not bend smoothly, or a non-overlapping region or an empty space (gap) may be generated, so that the welding strength cannot be sufficiently ensured when the segment 61 is bent toward the core. At the same time, if C2 exceeds 10 mm, it is difficult to manufacture the electrode plate while uniformly maintaining the flatness of the uncoated portion in the winding direction X. That is, an excessive height of the uncoated portion results in an arc surface in the uncoated portion.

[0269] In addition, the separation distance (C3) between the segments 61 can be adjusted within a range of 0.05 mm to 1 mm or 0.5 mm to 1 mm. If C3 is less than 0.05 mm, when the segment 61 is bent, the uncoated portion 43 near the baseline (DL) (near the bottom of the cut groove between two adjacent segments) may be torn due to stress. At the same time, if C3 exceeds 1 mm, a non-overlapping region or an empty space (gap) where the segments 61 do not overlap each other may be generated, so that the welding strength cannot be sufficiently ensured when the segment 61 is bent.

[0270] In an embodiment of the present disclosure, the corners of the two segments can be linearly connected. That is, the bottom of the cut groove can have a straight shape extending in the winding direction (X). A circular reinforcing portion can be added at the corner.

[0271] The radius (r) of the circular reinforcing portion can be 0.02 mm or more. If the corresponding radius is equal to or greater than this value, the effect of stress distribution will surely be brought. The radius of the circular reinforcing portion can be 0.1 mm or less. If the radius exceeds 0.1 mm, the effect of stress dispersion will no longer increase, and the space near the bottom of the cut groove may decrease, thereby suppressing electrolyte impregnation.

[0272] Referring back to Figure 7a , the width (d B1 ) of the core-side uncoated portion B1 is designed by applying the condition that the segment 61 of the middle uncoated portion B2 does not cover the cavity in the core of the electrode assembly when bent toward the core.

[0273] In one example, the width (d B1 ) of the core-side uncoated portion B1 can be increased proportionally to the height of the segment 61 of Group 1.

[0274] In a specific example, when the electrode plate 60 is used to manufacture an electrode assembly for a cylindrical battery cell with a form factor of 46800, according to the diameter of the core of the electrode assembly, the width (d B1 ) of the uncoated portion B1 on the core side is set to 180 mm to 350 mm.

[0275] In one embodiment, the width of each segment group can be designed to form the same winding turn of the electrode assembly.

[0276] In a variant, the width and / or height and / or separation distance of the segments 61 belonging to the same segment group can gradually and / or stepwise and / or irregularly increase or decrease within the group.

[0277] Groups 1 to 7 are only examples of segment groups. The number of groups and the number of segments 61 included in each group can be adjusted so that the segments 61 overlap in multiple layers to disperse stress as much as possible during the bending process of the uncoated portion 43 and fully ensure the welding strength.

[0278] In another variant, the height of the peripheral uncoated portion B3 can gradually or stepwise decrease as in the first and second embodiments. In addition, the segment structure of the intermediate uncoated portion B2 can be extended to the peripheral uncoated portion B3 (see the dashed line). In this case, the peripheral uncoated portion B3 can also include multiple segments like the intermediate uncoated portion B2. In this case, the segments of the peripheral uncoated portion B3 can have a greater width and / or height and / or separation distance than the intermediate uncoated portion B2.

[0279] In a specific example, when the electrode plate 60 is used to manufacture an electrode assembly for a cylindrical cell with a form factor of 46800, the segments can be formed into eight groups. At this time, the segments of groups 1 to 7 can be formed in the intermediate uncoated portion B2, and the segments of group 8 can be formed in the peripheral uncoated portion B3, as described in the above variant.

[0280] In a specific example, the width (d B1 ) of the uncoated portion B1 on the core side can be 180 mm to 350 mm. The width of group 1 can be 35% to 40% of the width of the uncoated portion B1 on the core side. The width of group 2 can be 130% to 150% of the width of group 1. The width of group 3 can be 120% to 135% of the width of group 2. The width of group 4 can be 85% to 90% of the width of group 3. The width of group 5 can be 120% to 130% of the width of group 4. The width of group 6 can be 100% to 120% of the width of group 5. The width of group 7 can be 90% to 120% of the width of group 6. The width of group 8 can be 115% to 130% of the width of group 7.

[0281] The reason why the widths of Groups 1 to 8 do not exhibit a pattern of constantly increasing or decreasing is that the segment widths gradually increase from Group 1 to Group 8, but the number of segments included in a group is restricted to an integer. Therefore, the number of segments can be reduced in a specific segment group. As a result, the width of the group can exhibit an irregular variation pattern as in the above example from the core to the outer periphery.

[0282] That is, assuming that the widths in the winding direction of each of three segment groups that are continuously adjacent to each other in the circumferential direction of the electrode assembly are W1, W2, and W3, respectively, a combination of segment groups in which W3 / W2 is less than W2 / W1 can be included.

[0283] In a specific example, Groups 4 to 6 correspond to this. The width ratio of Group 5 to Group 4 is 120% to 130%, and the width ratio of Group 6 to Group 5 is 100% to 120% which is less than 120% to 130%.

[0284] Figure 9a is a plan view showing the structure of the electrode plate 70 according to the fifth embodiment of the present disclosure.

[0285] Referring to Figure 9a , the electrode plate 70 of the fifth embodiment is basically the same as the fourth embodiment (or variant), except that the shape of the segment 61' is changed from a rectangle to a trapezoid compared to the fourth embodiment.

[0286] Figure 10 Shows the definition of the width, height, and separation distance of the trapezoidal segment 61'.

[0287] Referring to Figure 10 , the width D1, height D2, and separation distance D3 of the segment 61' are designed to prevent abnormal deformation of the uncoated portion 43 while sufficiently increasing the number of overlapping layers of the uncoated portion 43, so as to prevent the uncoated portion 43 near the baseline (D1) from being torn during the bending of the uncoated portion 43 and to ensure sufficient welding strength.

[0288] Preferably, the width D1 of the segment 61' can be adjusted within a range of 1 mm to 6 mm. If D1 is less than 1 mm, there may be a region where the segments 61' do not overlap or an empty space (gap), so that sufficient welding strength cannot be ensured when the segment 61' is bent toward the core. At the same time, if D1 exceeds 6 mm, when the segment 61' is bent due to the curvature of the wound electrode, the uncoated portion 43 near the baseline DL may be torn due to stress. In addition, the height of the segment 61' can be adjusted within a range of 2 mm to 10 mm. If D2 is less than 2 mm, the segment 61' may not bend smoothly, or there may be a region where the segments 61' do not overlap or an empty space (gap), so that sufficient welding strength cannot be ensured when the segment 61' is bent toward the core. At the same time, if D2 exceeds 10 mm, it is difficult to manufacture the electrode plate while uniformly maintaining the flatness of the uncoated portion 43 in the winding direction. In addition, the separation distance D3 of the segment 61' can be adjusted within a range of 0.05 mm to 1 mm or 0.5 mm to 1 mm. If D3 is less than 0.05 mm, when the segment 61' is bent, the uncoated portion 43 near the baseline may be torn due to stress. At the same time, if D3 exceeds 1 mm, there may be a region where the segments 61' do not overlap each other or an empty space (gap), so that sufficient welding strength cannot be ensured when the segment 61' is bent.

[0289] When the segment is trapezoidal, the separation distance D3 can be defined as the distance between the corners of two adjacent segments 61'. The corners of two adjacent segments can be connected by a straight line. That is, the bottom of the cut groove can have a straight shape extending in the winding direction (X).

[0290] A circular reinforcing portion can also be provided at the corner. In this way, the stress concentration phenomenon that may occur at the corner can be solved.

[0291] The radius (r) of the circular reinforcing portion can be 0.02 mm or more. If the corresponding radius is equal to or greater than this value, the effect of stress distribution will surely be brought.

[0292] The radius of the circular reinforcing portion can be 0.1 mm or less. If the radius exceeds 0.1 mm, the effect of stress dispersion will no longer increase, and the space near the bottom of the cut groove may decrease, which may inhibit electrolyte impregnation.

[0293] The separation distances C3 and D3 can be determined in relation to the sizes C1 and D1 of the widths measured in the winding direction of the adjacent segments 61 and 61' that define the separation distances C3 and D3. For example, as the width of the segment in the winding direction increases, it is desirable to have a tendency for the separation distance therebetween to also increase. Accordingly, the electrolyte impregnation can be uniformly distributed in the winding direction of the electrode assembly.

[0294] The width of the segment in the winding direction can be set to gradually increase from the core of the electrode assembly toward the outer periphery. The width of the segment in the winding direction can gradually or stepwise increase from the core of the electrode assembly toward the outer periphery. For example, the widths C1 and D1 of the segment in the winding direction can be in the range of 1 mm to 6 mm, and can become smaller toward the core and larger toward the outer periphery.

[0295] Therefore, the separation distances C3 and D3 can also be in the range of 0.5 mm to 1 mm, and can gradually or stepwise increase from the core of the electrode assembly toward the outer periphery.

[0296] In the fifth embodiment, among the plurality of segments 61', the lower inner angle (θ) of the trapezoid can increase from the core toward the outer periphery. As the radius of the electrode assembly 70 increases, the radius of curvature also increases. If the lower inner angle (θ) of the segment 61' increases as the radius of the electrode assembly increases, the stress generated in the radial direction and the circumferential direction when the segment 61' is bent can be reduced. In addition, when the lower inner angle (θ) increases, when the segment 61' is bent, the area and the number of overlapping layers that overlap with the segment 61' on the inner side also increase, thereby ensuring uniform welding strength in the radial direction and the circumferential direction and making the bent surface flat.

[0297] In one example, when the electrode plate 70 is used for an electrode assembly of a cylindrical battery cell with a form factor of 46800, when the radius of the electrode assembly 70 increases from 4 mm to 22 mm, the inner angle of the segment 61' can gradually increase in the range of 60 degrees to 85 degrees.

[0298] In a variant, the height of the peripheral uncoated portion B3 can gradually or stepwise decrease as in the first and second embodiments. In addition, the segment structure of the intermediate uncoated portion B2 can be extended to the peripheral uncoated portion B3 (see the dashed line). In this case, the peripheral uncoated portion B3 can also include a plurality of segments like the intermediate uncoated portion B2. In this case, the segments of the peripheral uncoated portion B3 can have a larger width and / or height and / or separation distance than the segments of the intermediate uncoated portion B2.

[0299] As in the fourth and fifth embodiments, when the intermediate uncoated portion B2 includes a plurality of segments 60 and 60', the shape of each segment 60 and 60' can become triangular, semi-circular, semi-elliptical, parallelogram, etc.

[0300] In addition, according to the region of the intermediate uncoated portion B2, the shapes of the segments 60 and 60' can be changed differently. In one example, a circular shape (e.g., semi-circular, semi-elliptical, etc.) that is beneficial for stress distribution is applied to the region where stress concentration occurs, while a polygonal shape with the largest area (e.g., rectangular, trapezoidal, parallelogram, etc.) can be applied to the region where the stress is relatively low.

[0301] In the fourth and fifth embodiments, the segment structure of the intermediate uncoated portion B2 can also be applied to the core-side uncoated portion B1. However, if the segment structure is applied to the core-side uncoated portion B1, when the segments 60, 60' of the intermediate uncoated portion B2 are bent according to the radius of curvature of the core, the ends of the core-side uncoated portion B1 may bend outward, which is called reverse forming. Therefore, the core-side uncoated portion B1 has no segments, or even if the segment structure is applied to the core-side uncoated portion B1, it is desirable to control the width and / or height and / or separation distance of the segments 60, 60' in consideration of the core so that reverse forming does not occur.

[0302] The height of the segment where such reverse forming may occur can be less than about 3 mm. In addition, if the height of the segment is less than 2 mm, bending may not easily occur due to interference between the segment and the diaphragm. In addition, if the height of the segment is less than 4 mm, the segment welding process may not proceed smoothly. Therefore, for the purpose of bending, the minimum height (H min ) of the segment can be 2 mm or more or 3 mm or more or 4 mm or more or 5 mm or more. Therefore, the height of the minimum bending segment can be 2 mm or more or 3 mm or more or 4 mm or more or 5 mm or more.

[0303] Therefore, based on the baseline DL, the end SL of the diaphragm in the width direction exists within ±30% (based on the baseline) of the height (Ha) of the minimum bending segment in the segment where the height in the uncoated portion is greater than or equal to the minimum height (H min , for example, 2 mm or 3 mm or 4 mm or 5 mm or more) that allows bending, and the impregnation performance can be greatly improved. That is, when determining the minimum bending segment that defines the position of the end SL of the diaphragm in the width direction, segments or unbent segments that may cause reverse forming can be excluded.

[0304] From another perspective, based on the baseline DL, if the end SL of the diaphragm in the width direction exists within ±30% of the greater height {max(Ha, H min )} of the height (Ha) of the minimum bending segment existing in the uncoated portion and the minimum bendable height (H min ), the impregnation performance can be greatly improved.

[0305] From another perspective, based on the baseline DL, if the end SL of the diaphragm in the width direction exists within ±30% of the minimum bendable height (H min ), the impregnation performance can be greatly improved. This can be a range of baseline DL ±1.5 mm, baseline DL ±1.2 mm, baseline DL ±0.9 mm, or baseline DL ±0.6 mm.

[0306] Alternatively, the position of the end portion of the separator in the width direction may be within the range of DL±0.3Ha and DL±1.5 mm, or the position of the end portion of the separator in the width direction may be within the range of DL±0.3Ha and DL±1.2 mm, or the position of the end portion of the separator in the width direction may be within the range of DL±0.3Ha and DL±0.9 mm, or the position of the end portion of the separator in the width direction may be within the range of DL±0.3Ha and DL±0.6 mm.

[0307] The structure of the electrode plate of the above-described embodiment (variant) can be applied to at least one of the first electrode plate and the second electrode plate having different polarities included in the wound-core type electrode assembly. In addition, when the electrode structure of the above-described embodiment (variant) is applied to any one of the first electrode plate and the second electrode plate, the structure of the conventional electrode plate can be applied to the other of the first electrode plate and the second electrode plate. In addition, the structures of the electrode plates applied to the first electrode plate and the second electrode plate may be different from each other rather than the same.

[0308] For example, when the first electrode plate and the second electrode plate are the positive electrode plate and the negative electrode plate, respectively, any one of the above-described embodiment (variant) can be applied to the first electrode plate, while the structure of the conventional electrode plate (see Figure 1 ) can be applied to the second electrode plate.

[0309] As another example, when the first electrode plate and the second electrode plate are the positive electrode plate and the negative electrode plate, respectively, any one of the above-described embodiment (variant) can be selectively applied to the first electrode plate, and any one of the above-described embodiment (variant) can be selectively applied to the second electrode plate.

[0310] In the present disclosure, the positive electrode active material coated on the positive electrode plate and the negative electrode active material coated on the negative electrode plate may be any active material known in the art without limitation.

[0311] The positive electrode active material may include a lithium intercalation material selected from the following materials as a main component, but the present disclosure is not limited thereto: layered compounds (e.g., lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), or a compound substituted with one or more transition metals); lithium manganese oxide (LiMnO 2 ) (e.g., the molecular formula Li 1+x Mn 2-x O 4 (where x is from 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2);Copper lithium oxide (Li 2 CuO 2 );Vanadium oxide (e.g., LiV 3 O 8 、LiFe 3 O 4 、V 2 O 5 、Cu 2 V 2 O 7 );Lithiated nickel oxide represented by the formula LiNi 1-x M x O 2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3); Lithium manganese composite oxide represented by the formula LiMn 2-x M x O 2 (where M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li 2 Mn 3 MO 8 (where M = Fe, Co, Ni, Cu or Zn); LiMn in which part of the lithium is replaced by alkaline earth metal ions 2 O 4 ; Sulfide compounds; Fe 2 (MoO 4 ) 3 ; Or a composite oxide formed by a combination thereof.

[0312] The positive electrode current collector has a thickness of, for example, 3 μm to 500 μm. The positive electrode current collector is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium or calcined carbon can be used; or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The electrode current collector can increase the adhesion of the positive electrode active material by forming fine irregularities on its surface, and can have various forms (e.g., film, sheet, foil, net, porous body, foam, non-woven body, etc.).

[0313] The conductive material can be additionally mixed with the positive electrode active material particles. Based on the total weight of the mixture containing the positive electrode active material, for example, the conductive material is added in an amount of 1 wt% to 50 wt%. The conductive material is not particularly limited as long as it has high conductivity and does not cause chemical changes in the battery, and for example, conductive materials selected from the following materials can be used: graphite (e.g., natural graphite and artificial graphite); carbon black (e.g., carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black); conductive fibers (e.g., carbon fibers and metal fibers); metal powders (e.g., carbon fluoride, aluminum, and nickel powder); conductive whiskers (e.g., zinc oxide and potassium titanate); conductive oxides (e.g., titanium oxide); polyphenylene derivatives, etc.

[0314] In addition, the separator and the negative electrode are manufactured by coating and drying the negative electrode active material particles on the negative electrode current collector, and if necessary, components such as the conductive material, binder, solvent, etc. as described above can also be included.

[0315] The negative electrode current collector has a thickness of, for example, 3 μm to 500 μm. The negative electrode current collector is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, or copper can be used; stainless steel surface-treated with carbon, nickel, titanium, silver, etc.; aluminum cadmium alloy, etc. In addition, like the positive electrode current collector, fine irregularities can be formed on the surface of the negative electrode current collector to enhance the bonding force of the negative electrode active material, and the negative electrode current collector can be used in various forms (e.g., film, sheet, foil, net, porous body, foam, non-woven body, etc.).

[0316] For example, carbon (e.g., non-graphitizable carbon and graphitic carbon) can be used as the negative electrode active material; Li x Fe 2 O 3 (0 ≤ x ≤ 1); Li x WO 2 (0 ≤ x ≤ 1); Sn x Me 1-x Me’ y O z of metal composite oxides (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1 elements of the periodic table, Group 2 elements, Group 3 elements, halogens, 0 < x ≤ 1, 1 ≤ y ≤ 3, 1 ≤ z ≤ 8); lithium metal; lithium alloy; silicon-based alloy; tin-based alloy; oxides (e.g., SnO, SnO 2 、PbO、PbO 2 、Pb 2 O 3 、Pb 3 O 4 、Sb 2 O3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi 2 O 3 , Bi 2 O 4 , Bi 2 O 5 ), conductive polymers (e.g., polyacetylene); Li-Co-Ni-based materials, etc.

[0317] Binder polymers that can be used for electrodes are components that contribute to the connection between electrode active material particles and conductive materials and the connection with the electrode current collector, and are added in an amount of, for example, 1 wt% to 50 wt% based on the total weight of the mixture containing the electrode active material. Examples of binder polymers include any binder polymer selected from the group consisting of the following materials, but are not limited thereto: polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF), polyvinylidene fluoride-trichloroethylene copolymer, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, and carboxymethyl cellulose, or a mixture of two or more thereof.

[0318] Non-limiting examples of solvents for preparing electrodes include acetone, tetrahydrofuran, dichloromethane, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or a mixture thereof. These solvents provide an appropriate viscosity level so that a slurry coating can be formed on the surface of the electrode current collector at the desired level.

[0319] The negative electrode may include: a current collector; and a negative electrode active material layer located on at least one surface of the current collector and including a negative electrode active material, a binder polymer, and a conductive material. The negative electrode active material layer may include a lower layer region in surface contact with the current collector and an upper layer region in surface contact with the lower layer region and extending to the surface of the negative electrode active material layer, and the lower layer region and the upper layer region may each independently include at least one of graphite and a silicon-based compound as the negative electrode active material.

[0320] The lower layer region may include natural graphite as the negative electrode active material, and the upper layer region may include artificial graphite as the negative electrode active material.

[0321] The lower layer region and the upper layer region may also each independently include a silicon-based compound as the negative electrode active material.

[0322] The silicon-based compound may include at least one of SiOx (0≤x≤2) and SiC.

[0323] According to an embodiment of the present disclosure, a negative electrode can be prepared by coating and drying a lower slurry containing a lower negative electrode active material on a current collector to form a lower layer, and then coating and drying an upper slurry containing an upper negative electrode active material on the lower layer region to form an upper layer.

[0324] In addition, according to an embodiment of the present disclosure, a negative electrode can be manufactured by the following steps: a step of preparing a lower slurry containing a lower negative electrode active material and an upper slurry containing an upper negative electrode active material;

[0325] a step of coating the lower slurry on one surface of a negative electrode current collector and coating the upper slurry on the lower slurry simultaneously or with a predetermined time difference; and

[0326] a step of simultaneously drying the coated lower slurry and the coated upper slurry to form an active material layer.

[0327] If the negative electrode is manufactured by the latter method, a mixing region (intermixing) where these different types of active materials are mixed with each other may exist in a portion where the lower layer region and the upper layer region of the negative electrode are in contact with each other. This is because, if the lower slurry containing the lower negative electrode active material and the upper slurry containing the upper negative electrode active material are continuously coated on the current collector simultaneously or with a very short time difference and then simultaneously dried to form an active material layer, a predetermined mixing region appears at the interface where the lower slurry and the upper slurry come into contact before drying, and then the mixing region becomes a layered mixing region while drying.

[0328] In the active material layer of the negative electrode according to an embodiment of the present disclosure, the weight ratio (or the ratio of the loading amount per unit area) of the upper layer region to the lower layer region may be from 20:80 to 50:50, particularly from 25:75 to 50:50.

[0329] The thicknesses of the lower layer region and the upper layer region of the active material layer of the negative electrode according to the present disclosure may not exactly match the thicknesses of the coated lower slurry and the coated upper slurry. However, as a result of a drying or selective rolling process, the thickness ratio of the lower layer region and the upper layer region of the negative electrode active material layer of the negative electrode finally obtained according to the present disclosure can match the thickness ratio of the coated lower slurry and the coated upper slurry.

[0330] According to one embodiment of the present disclosure in which a first slurry is coated and a second slurry is coated on the first slurry simultaneously or with a predetermined time difference, the predetermined time difference may be 0.6 seconds or less, or 0.02 seconds to 0.6 seconds, or 0.02 seconds to 0.06 seconds, or 0.02 seconds to 0.03 seconds. Due to the coating equipment, a time difference is generated during the coating of the first slurry and the second slurry. Therefore, it is more preferable to coat the first slurry and the second slurry simultaneously. A device such as a double-slot die can be used to coat the second slurry on the first slurry.

[0331] The step of forming the active material layer may further include a step of rolling the active material layer after the drying step. In this case, the rolling can be performed by a method commonly used in the art (e.g., roll pressing), and for example, it can be performed at a pressure of 1 MPa to 20 MPa and a temperature of 15 °C to 30 °C.

[0332] The step of simultaneously drying the coated lower-layer slurry and upper-layer slurry to form the active material layer can be performed using a device that combines a hot-air drying device and an infrared drying device, and can be achieved by a method commonly used in the art.

[0333] The wt% of the first binder polymer in the solid content of the lower-layer slurry may be equal to or greater than the wt% of the second binder polymer in the solid content of the upper-layer slurry. According to one embodiment of the present disclosure, the wt% of the first binder polymer in the solid content of the lower-layer slurry may be 1.0 to 4.2 times, or 1.5 to 3.6 times, or 1.5 to 3 times the wt% of the second binder polymer in the solid content of the upper-layer slurry.

[0334] At this time, when the ratio of the wt% of the first binder in the coated lower-layer slurry to the wt% of the second binder in the coated upper-layer slurry satisfies the above range, the binder in the lower layer region will not be too small to cause the separation of the electrode layer, and since the binder in the upper layer region will not be too large, the resistance of the upper layer region of the electrode can be reduced, and this can be beneficial to the fast charging performance.

[0335] In the solid content of the lower-layer slurry, the wt% of the first binder polymer may be 2 wt% to 30 wt%, or 5 wt% to 20 wt%, or 5 wt% to 20 wt%, and the proportion (wt%) of the second binder polymer in the solid content of the upper-layer slurry may be 0.5 wt% to 20 wt%, or 1 wt% to 15 wt%, or 1 wt% to 10 wt% or 2 wt% to 5 wt%.

[0336] The total proportion (wt%) of the first binder polymer and the second binder polymer in the solid content of both the lower-layer slurry and the upper-layer slurry may be 2 wt% to 20 wt% or 5 wt% to 15 wt%.

[0337] The separator includes: a porous polymer substrate; and a porous coating located on at least one or both surfaces of the porous polymer substrate and having inorganic particles and a binder polymer.

[0338] The porous polymer substrate may be a polyolefin-based porous substrate.

[0339] The polyolefin porous substrate may be in the form of a porous membrane or a non-woven fabric. Due to such a porous structure of the polyolefin porous substrate, the electrolyte can move smoothly between the positive electrode and the negative electrode, and the electrolyte impregnation performance of the substrate itself can also be improved, thereby ensuring excellent ionic conductivity. In addition, since an increase in the resistance inside the electrochemical device is prevented, a decrease in the performance of the electrochemical device can be prevented.

[0340] The polyolefin porous substrate used in the present disclosure may use any planar porous substrate commonly used in electrochemical devices, and its material or shape may be selected in various ways according to the use.

[0341] The polyolefin porous substrate may be (but is not limited to) a membrane or a non-woven fabric formed of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, or a mixture of two or more of them, but is not limited thereto.

[0342] The polyolefin porous substrate may have a thickness of 5 μm to 30 μm, but this is only an example, and thicknesses outside this range may also be considered in view of the mechanical properties and high-speed charge / discharge characteristics of the battery.

[0343] In one embodiment of the present disclosure, the porous substrate may be a porous membrane including a polyolefin-based polymer resin. The porous membrane can be obtained by a conventional method for manufacturing a polymer membrane and can be prepared by melt-extruding and stretching a polymer material, or can be formed by dissolving a pore-forming agent to form pores, but is not limited thereto. In a specific embodiment, the porosity of the porous membrane may be 30 vol% to 60 vol%. At the same time or independently thereof, the pores of the porous membrane may have a diameter in the range of 10 nm to 5 μm (preferably 10 nm to 2 μm). When the porosity of the porous substrate satisfies the above range, smooth movement of lithium ions and / or electrolytes and appropriate penetration strength can be ensured.

[0344] At the same time, the porous membrane may have an elongation rate of 200% to 400% (more preferably 300% to 400%). If the elongation rate is less than 200%, the possibility of contact between the electrodes when a nail penetrates increases, while if the elongation rate is greater than 400%, the area around the nail penetration will also elongate to make the separator thinner, thereby reducing the barrier property (blocking).

[0345] The nonwoven sheet according to the present disclosure may be formed of polyethylene (PE), polypropylene (PP), or a mixture of two or more thereof. For example, the nonwoven sheet may be manufactured by fiber spinning. For example, the meltblowing method may be used to manufacture the nonwoven sheet by forming the fibers of the above materials into a fiber spinning form and performing mixed spinning at a temperature equal to or higher than the melting point.

[0346] The nonwoven sheet may have an elongation rate of 200% to 400% (more preferably 300% to 400%). If the elongation rate is less than 200%, the possibility of contact between the electrodes when the nail penetrates increases, and if the elongation rate is greater than 400%, the area around the nail penetration also elongates, making the separator thinner and thus reducing the barrier property.

[0347] The nonwoven sheet may have a plurality of pores with an average diameter of 0.1 μm to 10 μm. If the pore diameter is less than 0.1 μm, lithium ions and / or electrolytes may not move smoothly. If the pore diameter is greater than 10 μm, the effect of preventing contact between the positive electrode and the negative electrode by stretching the nonwoven sheet during nail penetration according to the present disclosure may not be achieved.

[0348] In addition, the nonwoven sheet may have a porosity of 40 vol% to 70 vol%. If the porosity is less than 40 vol%, lithium ions and / or electrolytes may not move smoothly. If the porosity is greater than 70 vol%, the effect of preventing contact between the positive electrode and the negative electrode by stretching the nonwoven sheet during nail penetration according to the present disclosure may not be achieved. The nonwoven sheet prepared in this way may have a permeability of 1 s / 100 mL to 20 s / 100 mL.

[0349] In addition, the nonwoven sheet may have a thickness of 10 μm to 20 μm, but this is only an example and the present disclosure is not limited thereto. Depending on the permeability of the nonwoven sheet, a nonwoven sheet with a thickness outside this range may be employed.

[0350] The nonwoven sheet may be laminated to a component of the separator placed below the nonwoven sheet. The lamination may be performed in a temperature range of 100°C to 150°C. If the lamination is performed at a temperature lower than 100°C, the lamination effect will not occur, and if the lamination is performed at a temperature higher than 150°C, the nonwoven fabric will partially melt.

[0351] When compared with a separator made of a conventional nonwoven sheet or a separator having a layer containing inorganic particles formed on at least one surface of the membrane or nonwoven sheet, the separator according to an embodiment of the present disclosure (which is laminated and joined under the above conditions) has improved tolerance to nail penetration.

[0352] In a porous coating, inorganic particles can be bonded to each other through a binder polymer while being charged and in contact with each other. Therefore, an interstitial volume can be formed between the inorganic particles, and the interstitial volume between the inorganic particles becomes empty space to form pores.

[0353] As the inorganic particles for forming a porous coating, inorganic particles that do not undergo oxidation and / or reduction reactions within the operating voltage range of an electrochemical device (for example, based on Li / Li+, 0 V to 5 V) can be added and used. In particular, when inorganic particles with ion transport ability are used, the performance can be improved by increasing the ionic conductivity in the electrochemical device. In addition, when inorganic particles with a high dielectric constant are used, since the high dielectric constant helps to increase the degree of dissociation of electrolyte salts such as lithium salts in the liquid electrolyte, the ionic conductivity of the electrolyte can be increased.

[0354] For the above reasons, the inorganic particles preferably include high-dielectric inorganic particles with a dielectric constant of 5 or greater (preferably 10 or greater), inorganic particles with lithium ion migration ability, or a mixture thereof.

[0355] Non-limiting examples of inorganic particles with a dielectric constant of 5 or greater include BaTiO 3 , Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), PB(Mg 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 (PMN-PT), hafnium oxide (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 , SiC or aluminum hydroxide (for example, boehmite (γ-AlO(OH)), pseudo-boehmite (Al 2 O 3 ·H 2 O), diaspore (α-AlO(OH)), bayerite (α-AlO(OH) 3 ), gibbsite (γ-AlO(OH) 3 ), nordstrandite (AlO(OH) 3)) or a mixture thereof.

[0356] In particular, the above-mentioned inorganic particles (e.g., BaTiO 3 , Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), PB(Mg 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 (PMN-PT) and hafnium oxide (HfO 2 )) not only exhibit high dielectric properties with a dielectric constant of 100 or greater, but also have piezoelectricity, where when a certain pressure is applied to cause tension or compression, charges are generated to create a potential difference between two surfaces. Therefore, the safety of the electrochemical device can be improved by preventing internal short circuits between the two electrodes. In addition, when the above-mentioned high-dielectric inorganic particles and inorganic particles with lithium-ion migration ability are mixed, their synergistic effect can be doubled.

[0357] Inorganic particles with lithium-ion migration ability refer to inorganic particles that contain lithium elements but have the function of moving lithium ions without storing lithium. Since inorganic particles with lithium-ion migration ability can migrate and move lithium ions due to certain defects in the particle structure, the lithium-ion conductivity in the battery can be improved, which leads to an improvement in battery performance. Non-limiting examples of inorganic particles with lithium-ion migration ability include lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4 ) 3 , 0 < x < 2, 0 < y < 1, 0 < z < 3), such as 14Li 2 O-9Al 2 O 3 -38TiO 2 -39P 2 O 5 of (LiAlTiP) x O y -based glass (0 < x < 4, 0 < y < 13), lithium lanthanum titanate (Li x La y TiO 3, where 0 < x < 2, 0 < y < 3), such as Li 3.25 Ge 0.25 P 0.75 S 4 lithium germanium thiophosphate (Li x Ge y P z S w , where 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), such as Li 3 lithium nitride (Li x N y , where 0 < x < 4, 0 < y < 2), such as Li 3 PO 4 -Li 2 S-SiS 2 SiS 2 -based glass (Li x Si y S z , where 0 < x < 3, 0 < y < 2, 0 < z < 4), such as LiI-Li 2 S-P 2 S 5 P 2 S 5 -based glass (Li x P y S z , where 0 < x < 3, 0 < y < 3, 0 < z < 7) or a mixture thereof.

[0358] In one embodiment of the present disclosure, the inorganic particles may include inorganic particles having hydrophilicity. Examples of inorganic particles having hydrophilicity include inorganic particles based on Al 2 O 3 or aluminum hydroxide. In addition, examples of inorganic particles based on aluminum hydroxide include boehmite (γ-AlO(OH)), pseudoboehmite (Al 2 O 3 ·H 2 O), diaspore (α-AlO(OH)), bayerite (α-AlO(OH) 3 ), gibbsite (γ-AlO(OH) 3 ), nordstrandite (AlO(OH) 3) etc. In one embodiment of the present disclosure, the separator may include at least one or more inorganic particles having such hydrophilicity. In particular, when a hydrophilic organic solvent such as a carbonate-based organic solvent is used as the organic solvent for the electrolyte, if inorganic particles having such hydrophilicity are applied to the porous coating of the separator, the electrolyte impregnation performance of the electrode assembly can be further improved. In one embodiment of the present disclosure, when a separator substrate made of a polyolefin-based material is used, since the separator substrate exhibits hydrophobicity, it may be difficult to ensure sufficient wettability by the electrolyte. In this case, when inorganic particles having hydrophilicity are applied to the porous coating formed on its surface, the low wettability of the separator due to the hydrophobicity of the polyolefin-based separator substrate can be prevented. The size of the inorganic particles of the porous coating is not limited, but is preferably 0.001 μm to 10 μm for forming a coating having a uniform thickness and an appropriate porosity. If the size is less than 0.001 μm, the dispersibility of the inorganic particles may decrease, while if the size exceeds 10 μm, the thickness of the porous coating may increase, deteriorating the mechanical properties, and the possibility of internal short circuit during battery charging and discharging increases due to the too large pore size.

[0359] Meanwhile, the binder polymer for forming the porous coating may be any binder polymer selected from the group consisting of the following materials, but is not limited thereto: polyvinylidene, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF), polyvinylidene fluoride-trichloroethylene copolymer, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, ethylene-vinyl acetate copolymer (ethylene-vinyl acetate copolymer), polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, and carboxymethyl cellulose or a mixture of two or more thereof.

[0360] The composition ratio of the inorganic particles and the binder polymer used in the porous coating may preferably be in the range of 50:50 to 99:1 (more preferably 70:30 to 95:5), for example. If the content ratio of the inorganic particles to the binder polymer is less than 50:50, the content of the binder polymer increases, and the improvement of the thermal stability of the separator may become poor. In addition, due to the reduction of the empty space formed between the inorganic particles, the pore size and porosity may decrease, which may lead to a reduction in the final battery performance. If the content of the inorganic particles exceeds 99 parts by weight, the peel resistance of the porous coating may be weakened due to the too small content of the binder polymer.

[0361] The thickness of the porous coating is not particularly limited, but is preferably in the range of 0.01 μm to 20 μm. In addition, the pore diameter and porosity are not particularly limited, but the pore diameter is preferably in the range of 0.001 μm to 10 μm, and the porosity is preferably in the range of 10 vol% to 90 vol%. The pore diameter and porosity mainly depend on the size of the inorganic particles. For example, when inorganic particles with a particle size of 1 μm or less are used, pores are also formed to have a size of about 1 μm or less. Such a pore structure is filled with an electrolyte to be subsequently injected, and the electrolyte filled in this way has an ion migration effect. If the pore diameter and porosity are less than 0.001 μm and 10 vol%, respectively, the pores may act as a resistance layer, and if the pore diameter and porosity exceed 10 μm and 90 vol%, respectively, the mechanical properties will be reduced.

[0362] A porous coating can be formed by dissolving or dispersing a binder polymer in a dispersion medium, and then adding inorganic particles to obtain a slurry for forming the porous coating, and coating and drying the slurry on at least one surface of a substrate. The dispersion medium preferably has a solubility coefficient similar to that of the binder polymer and a low boiling point. This is to facilitate the uniform mixing of the dispersion medium and its subsequent removal. Non-limiting examples of the dispersion medium that can be used include acetone, tetrahydrofuran, dichloromethane, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or a mixture thereof.

[0363] After adding the inorganic particles to a dispersion in which the binder polymer is dispersed in a dispersion medium, it is preferable to crush the inorganic particles. In this case, the crushing time is preferably 1 hour to 20 hours, and as described above, the particle size of the crushed inorganic particles is preferably 0.001 μm to 10 μm. For the crushing method, a conventional method can be used and ball milling is particularly preferred.

[0364] Thereafter, under humidity conditions of 10% to 80%, the binder polymer dispersion in which the inorganic particles are dispersed is coated on at least one surface of a porous polymer substrate and dried. The method of coating the dispersion on the porous polymer substrate can use various conventional coating methods known in the art (e.g., dip coating, die coating, roll coating, dot coating, or a combination thereof).

[0365] For the components of the porous coating, in addition to the above-mentioned inorganic particles and binder polymer, other additives (e.g., conductive agents) can also be included.

[0366] The finally manufactured separator according to the present disclosure may have a thickness of 1 μm to 100 μm or 5 μm to 50 μm. If the thickness is less than 1 μm, the function of the separator may not be fully exerted, and the mechanical properties may deteriorate. In addition, the separator may have a porosity of 40 vol% to 60 vol% and a permeability of 150 s / 100 mL to 300 s / 100 mL.

[0367] According to one embodiment of the present disclosure, the porous polymer substrate may be of the polyethylene or polypropylene series. In addition, Al oxide and Si oxide-based coating materials may be used as inorganic particles in the porous coating.

[0368] In one embodiment of the present disclosure, the separator may have a porous coating on both surfaces of the porous polymer substrate. In this case, a uniform solid electrolyte interface layer can be formed by improving the impregnation performance of the electrolyte, and excellent air permeability can be ensured compared with a conventional single-sided inorganic coating separator. For example, the air permeability may be within 120 s / 100 cc. In addition, even if the inorganic porous coating is provided on both surfaces, the thickness of the conventional single-sided inorganic coating separator can be achieved. For example, the thickness may be less than 15.0 μm.

[0369] In another embodiment of the present disclosure, the separator may have a porous coating provided on one of the two surfaces of the porous polymer substrate, and in this case, the porous coating may preferably be provided facing the positive electrode. In this case, it is beneficial to increase the energy density because the volume of the electrode assembly can be minimized without compromising the insulation performance and mechanical properties of the separator, or the amount of the electrode active material can be increased in the same volume.

[0370] In addition, when using the separator according to the embodiment of the present disclosure, the stability of the separator is improved to ensure heat resistance and pressure resistance. Specifically, heat resistance with a thermal shrinkage characteristic of less than 5% based on 180 °C can be ensured, and a puncture strength performance of 550 gf or higher can be ensured. When core deformation occurs during the cycling of the battery using such a separator, damage or penetration of the separator in the stepped portion can be prevented.

[0371] Hereinafter, the structure of the electrode assembly according to one embodiment of the present disclosure will be described in detail.

[0372] Figure 11 is a cross-sectional view of the wound core type electrode assembly 80 taken along the Y-axis direction (winding axis direction), in which the electrode plate 40 of the first embodiment is applied to the first electrode plate (positive electrode plate) and the second electrode plate (negative electrode plate).

[0373] can be referred to by Figure 2The electrode assembly 80 is manufactured by the described winding method. For ease of description, the protruding structures of the uncoated portions 43a, 43b extending outside the separator are shown in detail, and the winding structure of the first electrode plate, the second electrode plate, and the separator is not depicted. The upwardly protruding uncoated portion 43a extends from the first electrode plate, and the downwardly protruding uncoated portion 43b extends from the second electrode plate.

[0374] A pattern in which the heights of the uncoated portions 43a, 43b change is schematically shown. That is, the heights of the uncoated portions 43a, 43b can vary irregularly depending on the cross-sectional cutting position. For example, when the side portions of the trapezoidal segments 61, 61' are cut, the height of the uncoated portion in the cross-section is lower than the heights of the segments 61, 61'. Therefore, it should be understood that the heights of the uncoated portions 43a, 43b depicted in the drawings showing the cross-section of the electrode assembly correspond to the average value of the heights of the uncoated portions included in each winding turn ( Figure 8 C2 in Figure 10 and D2 in

[0375] Referring to Figure 11 , the uncoated portion 43a of the first electrode plate includes a core-side uncoated portion B1 adjacent to the core of the electrode assembly 80, a peripheral uncoated portion B3 adjacent to the outer peripheral surface of the electrode assembly 80, and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the peripheral uncoated portion B3.

[0376] The height (length in the Y-axis direction) of the peripheral uncoated portion B3 is relatively smaller than the height of the intermediate uncoated portion B2. Therefore, an internal short circuit can be prevented when the crimped portion of the battery can is pressed near the peripheral uncoated portion B3.

[0377] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In a variant, the lower uncoated portion 43b can have the structure of a conventional electrode plate or the structure of an electrode plate of other embodiments (variants).

[0378] The ends 81 of the upper uncoated portion 43a and the lower uncoated portion 43b can be bent from the outer periphery of the electrode assembly 80 toward the core. At this time, the peripheral uncoated portion B3 can be substantially not bent.

[0379] Figure 12 is a cross-sectional view of the wound-core type electrode assembly 90 taken along the Y-axis direction (winding axis direction), in which the electrode plate 45 of the second embodiment is applied to the first electrode plate (positive electrode plate) and the second electrode plate (negative electrode plate).

[0380] Referring to Figure 12, the uncoated portion 43a of the first electrode plate includes a core-side uncoated portion B1 adjacent to the core of the electrode assembly 90, a peripheral uncoated portion B3 adjacent to the outer peripheral surface of the electrode assembly 90, and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the peripheral uncoated portion B3.

[0381] The height of the peripheral uncoated portion B3 is relatively smaller than the height of the intermediate uncoated portion B2 and gradually or stepwise decreases from the core to the outer periphery. Therefore, internal short circuit can be prevented when the crimped portion of the battery can is pressed near the peripheral uncoated portion B3.

[0382] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In a variant, the lower uncoated portion 43b may have the structure of a conventional electrode plate or the structure of an electrode plate of other embodiments (variants).

[0383] The ends 91 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery of the electrode assembly 90 toward the core. At this time, the outermost portion 92 of the peripheral uncoated portion B3 may be substantially not bent.

[0384] Figure 13 is a cross-sectional view of the wound-core type electrode assembly 100 taken along the Y-axis direction (winding axis direction), in which any one of the electrode plates 50, 60, 70 of the third to fifth embodiments (their variants) is applied to the first electrode plate (positive electrode plate) and the second electrode plate (negative electrode plate).

[0385] Refer to Figure 13 , the uncoated portion 43a of the first electrode plate includes a core-side uncoated portion B1 adjacent to the core of the electrode assembly 100, a peripheral uncoated portion B3 adjacent to the outer peripheral surface of the electrode assembly 100, and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the peripheral uncoated portion B3.

[0386] The height of the core-side uncoated portion B1 is relatively smaller than the height of the intermediate uncoated portion B2. In addition, the height of the uncoated portion 43a at the innermost side of the intermediate uncoated portion B2 is equal to or smaller than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0387] Therefore, even if the intermediate uncoated portion B2 is bent, the bending point does not block the cavity 102 in the core of the electrode assembly 100. If the cavity 102 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 102, the welding process between the current collector plate of the negative electrode and the battery can can be easily performed.

[0388] The height of the peripheral uncoated portion B3 is relatively smaller than the height of the intermediate uncoated portion B2. Therefore, an internal short circuit can be prevented from occurring when the curled portion of the battery can is pressed near the peripheral uncoated portion B3.

[0389] In a variant, different from that Figure 13 shown, the height of the peripheral uncoated portion B3 can be gradually or stepwise decreased. Further, in Figure 13 , although the height of the intermediate uncoated portion B2 is partially the same in the circumferential direction, the height of the intermediate uncoated portion B2 can gradually or stepwise increase from the boundary between the core-side uncoated portion B1 and the intermediate uncoated portion B2 to the boundary between the intermediate uncoated portion B2 and the peripheral uncoated portion B3.

[0390] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In a variant, the lower uncoated portion 43b can have the structure of a conventional electrode plate or the structure of an electrode plate of other embodiments (variants).

[0391] The ends 101 of the upper uncoated portion 43a and the lower uncoated portion 43b can be bent from the outer periphery to the core of the electrode assembly 100. At this time, the core-side uncoated portion B1 and the peripheral uncoated portion B3 are substantially not bent.

[0392] When the intermediate uncoated portion B2 includes a plurality of segments, the bending stress can be released, thereby preventing the uncoated portion 43a near the baseline from being torn or abnormally deformed. Further, when the width and / or height and / or separation distance of the segments are adjusted according to the numerical ranges of the above-described embodiments, the segments are bent toward the core and overlap in multiple layers, thereby sufficiently ensuring the welding strength and not forming voids (gaps) in the bending surface (the surface viewed along the Y axis).

[0393] Figure 14 is a cross-sectional view of an electrode assembly 110 according to another embodiment of the present disclosure taken along the Y-axis direction (the winding axis direction).

[0394] Referring to Figure 14 , except that the height of the peripheral uncoated portion B3 is substantially the same as the outermost height of the intermediate uncoated portion B2, the electrode assembly 110 is substantially the same as the Figure 13 electrode assembly 100.

[0395] The peripheral uncoated portion B3 can include a plurality of segments that are substantially the same as the segments described in the fourth and fifth embodiments (variants).

[0396] In the electrode assembly 110, the height of the uncoated portion B1 on the core side is relatively smaller than the height of the intermediate uncoated portion B2. In addition, the height (H) of the uncoated portion located at the innermost side of the intermediate uncoated portion B2 is equal to or smaller than the radial length (R) of the uncoated portion B1 on the core side. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0397] Therefore, even if the intermediate uncoated portion B2 is bent, the bending point does not block the cavity 112 in the core of the electrode assembly 110. If the cavity 112 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 112, the welding process between the current collector plate of the negative electrode (or positive electrode) and the battery can (or external terminal) can be easily performed.

[0398] In a variant, the structure in which the height of the intermediate uncoated portion B2 gradually or stepwise increases from the core toward the periphery can extend to the peripheral uncoated portion B3. In this case, the height of the uncoated portion 43a can gradually or stepwise increase from the boundary between the uncoated portion B1 on the core side and the intermediate uncoated portion B2 to the outermost surface of the electrode assembly 110.

[0399] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In a variant, the lower uncoated portion 43b can have the structure of a conventional electrode plate or the structure of an electrode plate of other embodiments (variants).

[0400] The ends 111 of the upper uncoated portion 43a and the lower uncoated portion 43b can be bent from the outer periphery of the electrode assembly 110 toward the core. At this time, the uncoated portion B1 on the core side is substantially not bent.

[0401] When the intermediate uncoated portion B2 and the peripheral uncoated portion B3 include a plurality of segments, the bending stress can be released, thereby preventing the uncoated portions 43a and 43b near the cut valley from being torn or abnormally deformed. In addition, when adjusting the width and / or height and / or separation distance of the segments according to the numerical range of the above-described embodiment, the segments are bent toward the core and overlap in multiple layers to sufficiently ensure the welding strength, and no voids (gaps) are formed in the bending surface (the surface viewed along the Y axis).

[0402] Figure 15 It is a cross-sectional view of an electrode assembly 120 according to still another embodiment of the present disclosure taken along the Y-axis direction (the winding axis direction).

[0403] Refer to Figure 15 , except that the height of the intermediate uncoated portion B2 has a pattern of gradually or stepwise increasing and then decreasing, the electrode assembly 120 is substantially the same as Figure 13 the electrode assembly 100.

[0404] This height variation of the middle uncoated portion B2 can be achieved by using a stepped pattern (see Figure 6 ) or by adjusting the height of the segments included in the middle uncoated portion B2 that is not coated in the middle (see Figure 7a or 9a).

[0405] In the electrode assembly 120, the height of the core-side uncoated portion B1 is relatively smaller than the height of the middle uncoated portion B2. In addition, the height (H) of the uncoated portion located at the innermost side of the middle uncoated portion B2 is equal to or smaller than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0406] Therefore, even if the middle uncoated portion B2 bends toward the core, the bending point does not block the cavity 122 in the core of the electrode assembly 120. If the cavity 122 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 122, the welding process between the current collector plate of the negative electrode (or positive electrode) and the battery can (or external terminal) can be easily performed.

[0407] In addition, the height of the peripheral uncoated portion B3 is relatively smaller than the height of the middle uncoated portion B2. Therefore, an internal short circuit can be prevented when the crimped portion of the battery can presses near the peripheral uncoated portion B3. In a variant, the height of the peripheral uncoated portion B3 can gradually or stepwise decrease toward the outer periphery.

[0408] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In a variant, the lower uncoated portion 43b can have the structure of a conventional electrode plate or the structure of an electrode plate of other embodiments (variants).

[0409] The ends 121 of the upper uncoated portion 43a and the lower uncoated portion 43b can bend from the outer periphery of the electrode assembly 120 toward the core. At this time, the core-side uncoated portion B1 and the peripheral uncoated portion B3 are basically not bent.

[0410] When the middle uncoated portion B2 includes a plurality of segments, the bending stress can be released, thereby preventing the uncoated portions 43a and 43b from being torn or abnormally deformed. In addition, when adjusting the width and / or height and / or separation distance of the segments according to the numerical range of the above-described embodiment, the segments bend toward the core and overlap into multiple layers to sufficiently ensure the welding strength, and no voids (gaps) are formed in the bending surface (the surface viewed along the Y-axis).

[0411] Figure 16 FIG. is a cross-sectional view of an electrode assembly 130 according to still another embodiment of the present disclosure taken along the Y-axis direction (the winding axis direction).

[0412] Reference Figure 16 , except that the height of the peripheral uncoated portion B3 has a pattern that gradually or stepwise decreases from the boundary point between the peripheral uncoated portion B3 and the intermediate uncoated portion B2 toward the outermost surface of the electrode assembly 130, the electrode assembly 130 is substantially the same as the Figure 15 electrode assembly 120.

[0413] This height change of the peripheral uncoated portion B3 can be achieved by extending the stepped pattern (see Figure 6 ) included in the intermediate uncoated portion B2 to the peripheral uncoated portion B3 while gradually or stepwise decreasing the height of the pattern toward the outer periphery. In addition, in another variant, this height change of the peripheral uncoated portion B3 can be achieved by extending the segment structure of the intermediate uncoated portion B2 to the peripheral uncoated portion B3 while gradually or stepwise decreasing the height of the segment toward the outer periphery.

[0414] In the electrode assembly 130, the height of the core-side uncoated portion B1 is relatively smaller than the height of the intermediate uncoated portion B2. In addition, in the intermediate uncoated portion B2, the height (H) of the innermost uncoated portion is equal to or less than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0415] Therefore, even if the intermediate uncoated portion B2 bends toward the core, the bending point does not block the cavity 132 in the core of the electrode assembly 120. If the cavity 132 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 132, the welding process between the current collector plate of the negative electrode (or positive electrode) and the battery can (or external terminal) can be easily performed.

[0416] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In one variant, the lower uncoated portion 43b can have the structure of a conventional electrode plate or the structure of an electrode plate of other embodiments (variants).

[0417] The ends 131 of the upper uncoated portion 43a and the lower uncoated portion 43b can bend from the outer periphery of the electrode assembly 130 toward the core. At this time, the core-side uncoated portion B1 is substantially not bent.

[0418] When the intermediate uncoated portion B2 and the peripheral uncoated portion B3 include multiple segments, the bending stress can be released to prevent the uncoated portions 43a, 43b near the cut valley from being torn or abnormally deformed. In addition, when adjusting the width and / or height and / or separation distance of the segments according to the numerical range of the above embodiments, the segments bend toward the core and overlap into multiple layers to fully ensure the welding strength, and no voids (gaps) are formed in the bending surface (the surface viewed along the Y axis).

[0419] Various electrode assembly structures according to embodiments of the present disclosure can be applied to wound-core cylindrical battery cells.

[0420] Preferably, the cylindrical battery cell can be, for example, a cylindrical battery cell having a form factor ratio (defined as the value obtained by dividing the diameter of the cylindrical battery cell by its height, i.e., the ratio of the diameter (Φ) to the height (H)) greater than about 0.4.

[0421] Here, the form factor refers to the values representing the diameter and height of the cylindrical battery cell. The cylindrical battery cell according to an embodiment of the present disclosure can be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the numerical value representing the form factor, the first two digits represent the diameter of the cell, the next two digits represent the height of the cell, and the last digit "0" indicates that the cross-section of the cell is circular.

[0422] When an electrode assembly having a jointless structure is applied to a cylindrical battery cell with a form factor ratio greater than 0.4, the stress applied in the radial direction when the uncoated portion is bent is relatively large, such that the uncoated portion may be easily torn. In addition, when welding the current collector plate to the bent surface of the uncoated portion, it is necessary to sufficiently increase the number of overlapping layers of the uncoated portion in order to sufficiently ensure the welding strength and reduce the resistance. The above requirements can be achieved by the electrode plate and the electrode assembly according to the embodiments (variations) of the present disclosure.

[0423] A battery cell according to an embodiment of the present disclosure can be a cylindrical battery cell having a generally cylindrical shape, with a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0424] A battery cell according to another embodiment can be a cylindrical battery cell having a generally cylindrical shape, with a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0425] A battery cell according to yet another embodiment can be a cylindrical battery cell having a generally cylindrical shape, with a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0426] A battery cell according to yet another embodiment can be a cylindrical battery cell having a generally cylindrical shape, with a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0427] A battery cell according to yet another embodiment can be a cylindrical battery cell having a generally cylindrical shape, with a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0428] Battery cells with a form factor ratio of about 0.4 or less are typically used. That is, for example, 18650 cells, 21700 cells, etc. are typically used. The 18650 cell has a diameter of about 18 mm, a height of about 65 mm, and a form factor ratio of 0.277. The 21700 cell has a diameter of about 21 mm, a height of about 70 mm, and a form factor ratio of 0.300.

[0429] Hereinafter, a cylindrical battery cell according to an embodiment of the present disclosure will be described in detail.

[0430] Figure 17 is a cross-sectional view of a cylindrical battery cell 140 according to an embodiment of the present disclosure taken along the Y-axis direction.

[0431] Referring to Figure 17 , the cylindrical battery cell 140 according to an embodiment of the present disclosure includes an electrode assembly 141 having a first electrode plate, a separator, and a second electrode plate, a battery can 142 for accommodating the electrode assembly 141, and a seal 143 for sealing an open end of the battery can 142.

[0432] The battery can 142 is a cylindrical container having an opening at the top. The battery can 142 is made of a conductive metal material such as aluminum or steel. The battery can 142 accommodates the electrode assembly 10 in the internal space through the top opening and also accommodates an electrolyte.

[0433] The electrolyte may be a salt having a structure similar to A + B - Here, A + includes alkali metal cations such as Li + , Na + or K + or a combination thereof, and B - includes at least one anion selected from the group consisting of: F - , Cl - , Br - , I - , NO 3 - , N(CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - 、AsF 6 - 、BF 2 C 2 O 4 - 、BC 4 O 8 - 、(CF 3 ) 2 PF 4 - 、(CF 3 ) 3 PF 3 - 、(CF 3 ) 4 PF 2 - 、(CF 3 ) 5 PF - 、(CF 3 ) 6 P - 、CF 3 SO 3 - 、C 4 F 9 SO 3 - 、CF 3 CF 2 SO 3 - 、(CF 3 SO 2 ) 2 N - 、(FSO 2 ) 2 N - 、CF 3 CF 2 (CF 3 ) 2 CO - 、(CF 3 SO 2 ) 2 CH - 、(SF 5 ) 3 C - 、(CF 3 SO 2 ) 3 C - 、CF 3 (CF 2 ) 7 SO 3- , CF 3 CO 2 - , CH 3 CO 2 - , SCN - and (CF 3 CF 2 SO 2 ) 2 N - .

[0434] The electrolyte can also be dissolved in an organic solvent. The organic solvent is not limited to a specific substance as long as it can be used as a solvent for the electrolyte of the electrochemical device. For example, the organic solvent can be a carbonate-based solvent such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.

[0435] The electrode assembly 141 can have a wound core shape. As Figure 2 shown, the electrode assembly 141 can be manufactured by winding a laminate formed by laminating a lower separator, a first electrode plate, an upper separator, and a second electrode plate at least once around a winding center C.

[0436] The first electrode plate and the second electrode plate have different polarities. That is, if one electrode plate has a positive polarity, the other electrode plate has a negative polarity. At least one of the first electrode plate and the second electrode plate can have the structure of the electrode plate according to the above-described embodiment (variant). In addition, the other of the first electrode plate and the second electrode plate can have the structure of a conventional electrode plate or the structure of the electrode plate according to the embodiment (variant).

[0437] The uncoated portion 146a of the first electrode plate and the uncoated portion 146b of the second electrode plate protrude from the upper and lower portions of the electrode assembly 141, respectively. The first electrode plate has the structure of the electrode plate according to the first embodiment (variant). Therefore, with respect to the uncoated portion 146a of the first electrode plate, the height of the peripheral uncoated portion B3 is less than the height of the uncoated portions in other regions. The peripheral uncoated portion B3 is spaced apart from the inner periphery of the battery can 142 (especially the curled portion 147) by a predetermined interval. Therefore, the peripheral uncoated portion B3 of the first electrode plate does not contact the battery can 142 electrically connected to the second electrode plate, thereby preventing an internal short circuit of the battery cell 140.

[0438] The uncoated portion 146b of the second electrode plate has the same height. In one variant, the uncoated portion 146b of the second electrode plate may have the same structure as the uncoated portion 146a of the first electrode plate. In another variant, the uncoated portion 146b of the second electrode plate may optionally have the structure of the uncoated portion of the electrode plate according to the embodiment (variant).

[0439] The sealing body 143 may include a cover plate 143a, a first gasket 143b for providing airtightness and insulation between the cover plate 143a and the battery can 142, and a connecting plate 143c electrically and mechanically coupled to the cover plate 143a.

[0440] The cover plate 143a is a component made of a conductive metal material and covers the top opening of the battery can 142. The cover plate 143a is electrically connected to the uncoated portion 146a of the first electrode plate and is electrically insulated from the battery can 142 through the first gasket 143b. Thus, the cover plate 143a can serve as the first electrode terminal of the cylindrical battery cell 140.

[0441] The cover plate 143a is placed on the crimped portion 147 formed on the battery can 142 and is fixed by a crimping portion 148. Between the cover plate 143a and the crimping portion 148, the first gasket 143b can be inserted to ensure the airtightness of the battery can 142 and the electrical insulation between the battery can 142 and the cover plate 143a. The cover plate 143a may have a protrusion 143d protruding upward from its center.

[0442] The battery can 142 is electrically connected to the uncoated portion 146b of the second electrode plate. Thus, the battery can 142 has the same polarity as the second electrode plate. If the second electrode plate has a negative polarity, the battery can 142 also has a negative polarity.

[0443] The battery can 142 includes a crimped portion 147 and a crimping portion 148 at its top. The crimped portion 147 is formed by press-fitting the periphery of the outer peripheral surface of the battery can 142. The crimped portion 147 prevents the electrode assembly 141 accommodated inside the battery can 142 from detaching through the top opening of the battery can 142 and can serve as a support portion on which the sealing body 143 is placed.

[0444] The inner circumference of the crimped portion 147 is spaced apart from the peripheral uncoated portion B3 of the first electrode plate at a predetermined interval. More specifically, the lower part of the inner circumference of the crimped portion 147 is spaced apart from the peripheral uncoated portion B3 of the first electrode plate by a predetermined interval. In addition, since the peripheral uncoated portion B3 has a lower height, even when the battery can 142 is press-fitted from the outside to form the crimped portion 147, the peripheral uncoated portion B3 is substantially not affected. Therefore, the peripheral uncoated portion B3 is not compressed by other components such as the crimped portion 147, thus preventing partial deformation of the shape of the electrode assembly 141 and preventing a short circuit inside the cylindrical battery cell 140.

[0445] Preferably, when the press-fitting depth of the crimped portion 147 is defined as D1 and the radial length from the inner circumference of the battery can 142 to the boundary point between the peripheral uncoated portion B3 and the intermediate uncoated portion B2 is defined as D2, the formula D1 ≤ D2 can be satisfied. In this case, when the battery can 142 is press-fitted to form the crimped portion 147, damage to the peripheral uncoated portion B3 is substantially prevented.

[0446] A crimping portion 148 is formed on the crimped portion 147. The crimping portion 148 has an extended and curved shape to cover the outer circumference of the cover plate 143a provided on the crimped portion 147 and a part of the upper surface of the cover plate 143a.

[0447] The cylindrical battery cell 140 may further include a first current collector plate 144 and / or a second current collector plate 145 and / or an insulator 146.

[0448] The first current collector plate 144 is connected to the upper part of the electrode assembly 141. The first current collector plate 144 is made of a conductive metal material such as aluminum, copper, nickel, etc., and is electrically connected to the uncoated portion 146a of the first electrode plate. A wire 149 may be connected to the first current collector plate 144. The wire 149 may extend upward in the direction above the electrode assembly 141 and be connected to the connection plate 143c or directly to the lower surface of the cover plate 143a. The wire 149 may be connected to other components by welding.

[0449] Preferably, the first current collector plate 144 may be integrally formed with the wire 149. In this case, the wire 149 may have the shape of an elongated plate extending outward near the center of the first current collector plate 144.

[0450] The first current collector plate 144 may include a plurality of uneven portions (not shown) radially formed on its lower surface. When the radial uneven portions are provided, the uneven portions can be press-fitted into the uncoated portion 146a of the first electrode plate by pressing the first current collector plate 144.

[0451] The first current collector plate 144 is connected to the end of the uncoated portion 146a of the first electrode plate. The uncoated portion 146a and the first current collector plate 144 can be connected, for example, by laser welding. The laser welding can be performed in such a way as to partially melt the base material of the current collector plate. In one variant, the first current collector plate 144 and the uncoated portion 146a can be welded in a state where solder is interposed therebetween. In this case, the solder can have a lower melting point than the first current collector plate 144 and the uncoated portion 146a. The laser welding can be replaced by resistance welding, ultrasonic welding, etc.

[0452] The second current collector plate 145 can be connected to the lower surface of the electrode assembly 141. One side of the second current collector plate 145 can be connected to the uncoated portion 146b of the second electrode plate by welding, and the other side can be connected to the inner bottom surface of the battery can 142 by welding. The connection structure between the second current collector plate 145 and the uncoated portion 146b of the second electrode plate can be substantially the same as the connection structure between the first current collector plate 144 and the uncoated portion 146a of the first electrode plate.

[0453] The uncoated portions 146a, 146b are not limited to the structures shown. Therefore, the uncoated portions 146a, 146b can selectively adopt not only the conventional uncoated portion structure, but also the uncoated portion structure of the electrode plate according to the embodiment (variant).

[0454] The insulator 146 can cover the first current collector plate 144. The insulator 146 can cover the first current collector plate 144 at the upper surface thereof, thereby preventing direct contact between the first current collector plate 144 and the inner periphery of the battery can 142.

[0455] The insulator 146 has a wire hole 151 such that the wire 149 extending upward from the first current collector plate 144 can be led out through the wire hole 151. The wire 149 is led out upward through the wire hole 151 and connected to the lower surface of the connection plate 143c or the lower surface of the cover plate 143a.

[0456] The peripheral region of the edge of the insulator 146 can be inserted between the first current collector plate 144 and the crimped portion 147 to fix the connection body of the electrode assembly 141 and the first current collector plate 144. Therefore, the movement of the connection body of the electrode assembly 141 and the first current collector plate 144 can be restricted in the height direction of the battery cell 140, thereby improving the assembly stability of the battery cell 140.

[0457] The insulator 146 can be made of an insulating polymer resin. In one example, the insulator 146 can be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0458] The battery can 142 may further include an exhaust portion 152 formed at its lower surface. The exhaust portion 152 corresponds to a region having a smaller thickness compared to the peripheral region of the lower surface of the battery can 142. The exhaust portion 152 is structurally weaker compared to the peripheral region. Therefore, when an abnormality occurs in the cylindrical battery cell 140 and the internal pressure increases to a predetermined level or higher, the exhaust portion 152 may rupture, allowing the gas generated inside the battery can 142 to be discharged to the outside.

[0459] The exhaust portion 152 may be formed continuously or discontinuously while presenting a circular shape at the lower surface of the battery can 142. In one variant, the exhaust portion 152 may be formed in a straight line pattern or other pattern.

[0460] Figure 18 is a cross-sectional view of a cylindrical battery cell 150 according to another embodiment of the present disclosure taken along the Y-axis direction.

[0461] Refer to Figure 18 , except that the structure of the electrode plate of the second embodiment (variant) is adopted in the uncoated portion 146a of the first electrode plate, the cylindrical battery cell 150 is substantially the same as the Figure 18 cylindrical battery cell 140.

[0462] Refer to Figure 18 , the uncoated portion 146a of the first electrode plate may have a shape in which the height of the peripheral uncoated portion B3 gradually or stepwise decreases toward the inner circumference of the battery can 142. Preferably, the virtual line connecting the top ends of the peripheral uncoated portion B3 may have the same or similar shape as the inner circumference of the crimped portion 147.

[0463] The peripheral uncoated portion B3 forms an inclined surface. Therefore, when the battery can 142 is press-fitted to form the crimped portion 147, it is possible to prevent the peripheral uncoated portion B3 from being compressed and damaged by the crimped portion 147. In addition, it is possible to suppress the phenomenon of internal short circuit caused by the peripheral uncoated portion B3 coming into contact with the battery can 142 having a different polarity.

[0464] The remaining components of the cylindrical battery cell 150 are substantially the same as those of the above embodiment (variant).

[0465] The uncoated portions 146a, 146b are not limited to the structures shown. Therefore, the uncoated portions 146a, 146b may selectively have not only the conventional uncoated portion structure, but also the uncoated portion structure of the electrode plate according to the embodiment (variant).

[0466] Figure 19 is a cross-sectional view of a cylindrical battery cell 160 according to yet another embodiment of the present disclosure taken along the Y-axis direction.

[0467] Refer toFigure 19 , except that the wire 149 connected to the first current collector plate 144 is directly connected to the cover plate 143a of the seal body 143 through the wire hole 151 of the insulator 146, and the insulator 146 and the first current collector plate 144 have a structure in close contact with the lower surface of the cover plate 143a, the cylindrical battery cell 160 is substantially the same as the above-mentioned cylindrical battery cells 140 and 150.

[0468] In the cylindrical battery cell 160, the diameter of the first current collector plate 144 and the outermost diameter of the middle uncoated portion B2 are smaller than the minimum inner diameter of the battery can 142. In addition, the diameter of the first current collector plate 144 may be equal to or greater than the outermost diameter of the middle uncoated portion B2.

[0469] Specifically, the minimum inner diameter of the battery can 142 may correspond to the inner diameter of the battery can 142 at the position where the crimped portion 147 is formed. At this time, the diameter of the first current collector plate 144 and the outermost diameter of the middle uncoated portion B2 are smaller than the inner diameter of the battery can 142 at the position where the crimped portion 147 is formed. In addition, the diameter of the first current collector plate 144 may be equal to or greater than the outermost diameter of the middle uncoated portion B2. The peripheral region of the edge of the insulator 146 may be inserted between the peripheral uncoated portion B3 and the crimped portion 147 in a downwardly bent state to fix the connection body of the electrode assembly 141 and the first current collector plate 144.

[0470] Preferably, the insulator 146 may include a portion covering the peripheral uncoated portion B3 and a portion covering the first current collector plate 144, and the portion connecting these two portions may have a form that bends together in response to the bending shape of the crimped portion 147. The insulator 146 can insulate the peripheral uncoated portion B3 from the inner periphery of the crimped portion 147, and at the same time insulate the first current collector plate 144 from the inner periphery of the crimped portion 147.

[0471] The first current collector plate 144 may be positioned higher than the lower part of the crimped portion 147 and may be connected to the core-side uncoated portion B1 and the middle uncoated portion B2. At this time, the press-in depth D1 of the crimped portion 147 is less than or equal to the distance D2 from the inner periphery of the battery can 142 to the boundary between the peripheral uncoated portion B3 and the middle uncoated portion B2. Therefore, the core-side uncoated portion B1, the middle uncoated portion B2, and the first current collector plate 144 connected thereto may be positioned higher than the lower part of the crimped portion 147. The lower part of the crimped portion 147 refers to the baseline area between the portion of the battery can 142 that houses the electrode assembly 141 and the crimped portion 147.

[0472] Since the uncoated portion B1 on the core side and the intermediate uncoated portion B2 occupy the inner space of the crimped portion 147 in the radial direction, the empty space between the electrode assembly 141 and the cover plate 143a can be minimized. In addition, the connection plate 143c in the empty space between the electrode assembly 141 and the cover plate 143a is omitted. Therefore, the wire 149 of the first current collector plate 144 can be directly connected to the lower surface of the cover plate 143a. According to the above structure, the empty space in the battery cell can be reduced, and the energy density can be maximized by the same amount as the reduced empty space.

[0473] In the cylindrical battery cell 160, the first current collector plate 144 and the second current collector plate 145 can be welded to the ends of the uncoated portions 146a, 146b in the same manner as in the above embodiment.

[0474] The uncoated portions 146a, 146b are not limited to the shown structure. Therefore, the uncoated portions 146a, 146b can selectively have not only the conventional uncoated portion structure but also the uncoated portion structure of the electrode plate according to the embodiment (variant).

[0475] Figure 20 It is a cross-sectional view of a cylindrical battery cell 170 according to another embodiment of the present disclosure taken along the Y-axis.

[0476] Refer to Figure 20 , the structure of the electrode assembly of the cylindrical battery cell 170 is substantially the same as that of the cylindrical battery cell 140 in Figure 17 , and other structures except the electrode assembly are changed.

[0477] Specifically, the cylindrical battery cell 170 includes a battery can 171 through which a riveting terminal 172 is installed. The riveting terminal 172 is installed on the closed surface (the upper surface in the figure) of the battery can 171. The riveting terminal 172 is riveted to the perforation of the battery can 171 in a state where a second washer 173 made of an insulating material is interposed therebetween. The riveting terminal 172 is exposed to the outside in a direction opposite to the direction of gravity.

[0478] The riveting terminal 172 includes a terminal exposed portion 172a and a terminal insertion portion 172b. The terminal exposed portion 172a is exposed to the outside of the closed surface of the battery can 171. The terminal exposed portion 172a may be generally located at the central portion of the closed surface of the battery can 171. The maximum diameter of the terminal exposed portion 172a may be larger than the maximum diameter of the perforation formed in the battery can 171. The terminal insertion portion 172b may be electrically connected to the uncoated portion 146a of the first electrode plate through the generally central portion of the closed surface of the battery can 171. The terminal insertion portion 172b may be riveted to the inner surface of the battery can 171. That is, the end of the terminal insertion portion 172b may have a shape bent toward the inner surface of the battery can 171. The maximum diameter of the end of the terminal insertion portion 172b may be larger than the maximum diameter of the perforation of the battery can 171.

[0479] The lower surface of the terminal insertion portion 172b may be welded to the first current collector plate 144 connected to the uncoated portion 146a of the first electrode plate. An insulating cover 174 made of an insulating material may be inserted between the first current collector plate 144 and the inner surface of the battery can 171. The insulating cover 174 covers the upper portion of the first current collector plate 144 and the top edge of the electrode assembly 141. Therefore, it is possible to prevent the uncoated portion B3 at the periphery of the electrode assembly 141 from contacting the inner surface of the battery can 171 having a different polarity and causing a short circuit. The terminal insertion portion 172b of the riveting terminal 172 may pass through the insulating cap 174 and be welded to the first current collector plate 144.

[0480] A second washer 173 is inserted between the battery can 171 and the riveting terminal 172 to prevent the battery can 171 and the riveting terminal 172 having opposite polarities from being in electrical contact with each other. Therefore, the upper surface of the battery can 171 having a generally flat shape can be used as the second electrode terminal of the cylindrical battery cell 170.

[0481] The second washer 173 includes a washer exposed portion 173a and a washer insertion portion 173b. The washer exposed portion 173a is inserted between the terminal exposed portion 172a of the riveting terminal 172 and the battery can 171. The washer insertion portion 173b is inserted between the terminal insertion portion 172b of the riveting terminal 172 and the battery can 171. When the terminal insertion portion 172b of the riveting terminal is inserted, the washer insertion portion 173b may be deformed together so as to be in close contact with the inner surface of the battery can 171. The second washer 173 may be made of, for example, a polymer resin having insulating properties.

[0482] The gasket exposed portion 173a of the second gasket 173 may have an extended shape to cover the outer periphery of the terminal exposed portion 172a of the riveted terminal 172. When the second gasket 173 covers the outer periphery of the riveted terminal 172, it is possible to prevent a short circuit from occurring when an electrical connection component such as a bus bar is coupled to the upper surface of the battery can 171 and / or the riveted terminal 172. Although not shown in the figure, the gasket exposed portion 173a may have an extended shape to cover not only the outer peripheral surface of the terminal exposed portion 172a but also a part of its upper surface.

[0483] When the second gasket 173 is made of a polymer resin, the second gasket 173 can be joined to the battery can 171 and the riveted terminal 172 by heat fusion. In this case, the airtightness at the joining interface between the second gasket 173 and the riveted terminal 172 and at the joining interface between the second gasket 173 and the battery can 171 can be enhanced. At the same time, when the gasket exposed portion 173a of the second gasket 173 has a shape extending to the upper surface of the terminal exposed portion 172a, the riveted terminal 172 can be integrally joined to the second gasket 173 by insert injection molding.

[0484] In the upper surface of the battery can 171, the remaining area 175 except for the area occupied by the riveted terminal 172 and the second gasket 173 corresponds to a second electrode terminal having a polarity opposite to that of the riveted terminal 172.

[0485] The second current collector plate 176 is coupled to the lower portion of the electrode assembly 141. The second current collector plate 176 is made of a conductive metal material such as aluminum, steel, copper, or nickel and is electrically connected to the uncoated portion 146b of the second electrode plate.

[0486] Preferably, the second current collector plate 176 is electrically connected to the battery can 171. To this end, at least a part of the edge of the second current collector plate 176 may be inserted and fixed between the inner surface of the battery can 171 and the first gasket 178b. In one example, at least a part of the edge of the second current collector plate 176 may be fixed to the curled portion 180 by welding in a state of being supported on the lower surface of the curled portion 180 formed at the bottom of the battery can 171. In a variant, at least a part of the edge of the second current collector plate 176 may be directly welded to the inner wall surface of the battery can 171.

[0487] The second current collector plate 176 may include a plurality of uneven portions (not shown) radially formed on the surface facing the uncoated portion 146b. When the uneven portions are formed, by pressing the second current collector plate 176, the uneven portions can be press-fitted into the uncoated portion 146b.

[0488] Preferably, the second current collector plate 176 and the end of the uncoated portion 146b may be joined by welding (e.g., laser welding).

[0489] The sealing body 178 for sealing the lower open end of the battery can 171 includes a cover plate 178a and a first gasket 178b. The first gasket 178b electrically isolates the cover plate 178a and the battery can 171. The crimping portion 181 fixes the edge of the cover plate 178a and the first gasket 178b together. The cover plate 178a has an exhaust portion 179. The configuration of the exhaust portion 179 is substantially the same as that of the above-described embodiment (variant).

[0490] Preferably, the cover plate 178a is made of a conductive metal material. However, since the first gasket 178b is inserted between the cover plate 178a and the battery can 171, the cover plate 178a does not have an electrode polarity. The sealing body 178 seals the lower open end of the battery can 171 and is used to discharge gas when the internal pressure of the battery cell 170 increases beyond a critical value.

[0491] Preferably, the riveting terminal 172 electrically connected to the uncoated portion 146a of the first electrode plate serves as the first electrode terminal. In addition, among the components on the upper surface of the battery can 171 that are electrically connected to the uncoated portion 146b of the second electrode plate through the second current collector plate 176, the component 175 other than the riveting terminal 172 serves as a second electrode terminal having a different polarity from the first electrode terminal. If the two electrode terminals are located at the upper part of the cylindrical battery cell 170 as described above, an electrical connection component such as a bus bar can be arranged only on one side of the cylindrical battery cell 170. This can simplify the battery pack structure and improve the energy density. In addition, since the component 175 serving as the second electrode terminal has a substantially flat shape, a sufficient bonding area can be ensured for bonding an electrical connection component such as a bus bar. Therefore, the cylindrical battery cell 170 can reduce the resistance at the joint of the electrical connection component to a desired level.

[0492] Meanwhile, the structure of the uncoated portion and the structure of the electrode assembly 141 are not limited to the structures shown in the drawings and can be replaced with the structures of the above-described embodiment (variant).

[0493] Figure 21 is a cross-sectional view of a cylindrical battery cell 180 according to another embodiment of the present disclosure taken along the Y axis.

[0494] Referring to Figure 21 , the structure of the electrode assembly 141 of the cylindrical battery cell 180 is substantially the same as that of the cylindrical battery cell 150 shown in Figure 18 , and the components other than the electrode assembly 141 are substantially the same as those of the cylindrical battery cell 170 shown in Figure 20 .

[0495] Therefore, the configurations of the embodiments (variations) regarding the cylindrical battery cells 150 and 170 can be equivalently applied to the cylindrical battery cell 180.

[0496] In addition, the structures of the electrode assembly 141 and the uncoated portions are not limited to the structures shown in the drawings, and the structures of the above embodiments (variations) can be used instead.

[0497] Figure 22 FIG. is a cross-sectional view of a cylindrical battery cell 190 according to another embodiment of the present disclosure taken along the Y-axis.

[0498] Referring to Figure 22 , the cylindrical battery cell 190 includes Figure 14 the electrode assembly 110 shown, and the components other than the electrode assembly 110 are substantially the same as those of the cylindrical battery cell 140 shown in Figure 17 .

[0499] Referring to Figure 22 , the uncoated portions 146a and 146b of the electrode assembly 110 are bent from the outer periphery toward the core portion. At this time, since the core-side uncoated portion B1 has a lower height than other portions, the core-side uncoated portion B1 is substantially not bent. The first current collector 144 can be welded to the bent surface of the uncoated portion 146a, and the second current collector 145 can be welded to the bent surface of the uncoated portion 146b. When the uncoated portions 146a and 146b are bent, bent surfaces can be formed on the upper and lower portions of the electrode assembly 110 while overlapping in multiple layers.

[0500] In the electrode assembly 110, the height of the core-side uncoated portion B1 is relatively smaller than the heights of other portions. Similarly, as shown in Figure 14 , the height (H) of the uncoated portion located at the innermost side of the middle uncoated portion B2 is equal to or less than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0501] Therefore, even when the uncoated portion 146a is bent toward the core portion, the cavity 112 in the core of the electrode assembly 110 can be opened upward without being blocked.

[0502] If the cavity 112 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 112, the welding process between the second current collector 145 and the battery can 142 can be easily performed.

[0503] When the uncoated portions 146a and 146b have a segmented structure, if the width and / or height and / or separation distance of the segments are adjusted to meet the numerical ranges of the above-described embodiments, the segments overlap in multiple layers when bent to sufficiently ensure the welding strength, and no empty space (gap) is formed in the bent surface.

[0504] The structure of the uncoated portions 146a and 146b can be changed to any structure according to the above-described embodiments (variations) different from the structure shown in the drawings. In addition, a conventional uncoated portion structure can be applied to any one of the uncoated portions 146a and 146b without limitation.

[0505] Figure 23 FIG. is a cross-sectional view of a cylindrical battery cell 200 according to another embodiment of the present disclosure taken along the Y-axis.

[0506] Referring to Figure 23 , the cylindrical battery cell 200 includes Figure 14 the electrode assembly 110 shown, and the components other than the electrode assembly 110 are substantially the same as those of the cylindrical battery cell 180 shown in Figure 21 .

[0507] Referring to Figure 23 , the uncoated portions 146a and 146b of the electrode assembly 110 are bent from the outer periphery toward the core portion. At this time, since the core-side uncoated portion B1 has a lower height than other portions, the core-side uncoated portion B1 is substantially not bent. The first current collector plate 144 can be welded to the bent surface of the uncoated portion 146a, and the second current collector plate 176 can be welded to the bent surface of the uncoated portion 146b.

[0508] In the electrode assembly 110, the height of the core-side uncoated portion B1 is relatively lower than the height of other portions. Similarly, as shown in Figure 14 , the height (H) of the uncoated portion located at the innermost side of the intermediate uncoated portion B2 is equal to or less than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0509] Therefore, even when the uncoated portions 146a and 146b are bent toward the core portion, the cavity 112 in the core of the electrode assembly 110 can be opened upward without being blocked.

[0510] If the cavity 112 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 112, the welding process between the first current collector plate 144 and the riveting terminal 172 can be easily performed.

[0511] When the uncoated portions 146a and 146b have a segment structure, if the width and / or height and / or separation distance of the segments are adjusted to satisfy the numerical range of the above-described embodiments, the segments can overlap into multiple layers when the segments are bent to sufficiently ensure the welding strength, and no empty space (gap) is formed in the bent surface.

[0512] The structure of the uncoated portions 146a and 146b can be changed to any structure according to the above-described embodiments (variations) different from the structure shown in the drawings. In addition, a conventional uncoated portion structure can be applied to any one of the uncoated portions 146a and 146b without limitation.

[0513] Figure 24 FIG. is a cross-sectional view of a cylindrical battery cell 210 according to another embodiment of the present disclosure taken along the Y-axis.

[0514] Referring to Figure 24 , the cylindrical battery cell 210 includes Figure 13 the electrode assembly 100 shown, and the components other than the electrode assembly 100 are substantially the same as the components of the cylindrical battery cell 140 shown in Figure 17 .

[0515] Preferably, the uncoated portions 146a and 146b of the electrode assembly 100 are bent from the outer periphery toward the core portion. At this time, since the core-side uncoated portion B1 and the peripheral uncoated portion B3 of the uncoated portion 146a have a lower height than other portions, they are substantially not bent. The same applies to the uncoated portion 146b. The first current collector plate 144 can be welded to the bent surface of the uncoated portion 146a, and the second current collector plate 145 can be welded to the bent surface of the uncoated portion 146b.

[0516] The height of the core-side uncoated portion B1 is relatively lower than the height of the intermediate uncoated portion B2. In addition, as shown in Figure 13 , the height (H) of the uncoated portion located at the innermost side of the intermediate uncoated portion B2 is equal to or less than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0517] Therefore, even when the uncoated portions 146a and 146b are bent toward the core portion, the cavity 102 in the core of the electrode assembly 100 can be opened upward without being blocked.

[0518] If the cavity 102 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity, the welding process between the second current collector plate 145 and the battery can 142 can be easily performed.

[0519] In addition, the height of the peripheral uncoated portion B3 is relatively lower than that of the intermediate uncoated portion B2. Therefore, when the uncoated portion 146a is bent, the peripheral uncoated portion B3 is substantially not bent. In addition, since the peripheral uncoated portion B3 is sufficiently separated from the crimped portion 147, the problem that the peripheral uncoated portion B3 is damaged when the crimped portion 147 is press-fitted can be solved.

[0520] When the uncoated portions 146a and 146b have a segmented structure, if the width and / or height and / or separation distance of the segments are adjusted to satisfy the numerical range of the above-described embodiment, the segments can overlap into multiple layers when the segments are bent to sufficiently ensure the welding strength, and no empty space (gap) is formed in the bent surface.

[0521] The structure of the uncoated portions 146a and 146b can be changed to any structure according to the above-described embodiment (variant) different from the structure shown in the drawings. In addition, a conventional uncoated portion structure can be applied to any one of the uncoated portions 146a and 146b without limitation.

[0522] Figure 25 is a cross-sectional view of a cylindrical battery cell 220 according to another embodiment of the present disclosure taken along the Y-axis.

[0523] Referring to Figure 25 , the cylindrical battery cell 220 includes Figure 13 the electrode assembly 100 shown, and the components other than the electrode assembly 100 are substantially the same as those of the cylindrical battery cell 180 shown in Figure 21 .

[0524] Preferably, the uncoated portions 146a and 146b of the electrode assembly 100 are bent from the outer periphery toward the core portion. At this time, since the core-side uncoated portion B1 of the uncoated portion 146a has a lower height than other portions, the core-side uncoated portion B1 is substantially not bent. The same applies to the uncoated portion 146b. The first current collector plate 144 can be welded to the bent surface of the uncoated portion 146a, and the second current collector plate 176 can be welded to the bent surface of the uncoated portion 146b.

[0525] In the electrode assembly 100, the height of the core-side uncoated portion B1 is relatively lower than that of the intermediate uncoated portion B2. In addition, as shown in Figure 13 , the height (H) of the innermost uncoated portion of the intermediate uncoated portion B2 is equal to or less than the radial length (R) of the core-side uncoated portion B1. Here, the height of the uncoated portion refers to the distance from the baseline to the first side surface or the height of the segment.

[0526] Therefore, even when the uncoated portion 146a is bent toward the core portion, the cavity 102 in the core of the electrode assembly 100 can be opened upward without being blocked.

[0527] If the cavity 102 is not blocked, there is no difficulty during the electrolyte injection process, and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the cavity 102, the welding process between the first current collector plate 144 and the riveting terminal 172 can be easily performed.

[0528] In addition, the peripheral uncoated portion B3 of the uncoated portion 146a has a smaller height than the intermediate uncoated portion B2. Therefore, when the uncoated portion 146a is bent, the peripheral uncoated portion B3 is substantially not bent. The same applies to the uncoated portion 146b.

[0529] When the uncoated portions 146a and 146b have a segmented structure, if the width and / or height and / or separation distance of the segments are adjusted to meet the numerical range of the above-described embodiments, the segments can overlap in multiple layers when the segments are bent to sufficiently ensure the welding strength, and no empty space (gap) is formed in the bent surface.

[0530] The structure of the uncoated portions 146a and 146b can be changed to any structure according to the above-described embodiments (variations) different from the structure shown in the drawings. In addition, a conventional uncoated portion structure can be applied to any one of the uncoated portions 146a and 146b without limitation.

[0531] The cylindrical battery cell according to the above-described embodiments (variations) can be used to manufacture a battery pack.

[0532] Figure 26 is a diagram schematically showing a battery pack according to an embodiment of the present disclosure.

[0533] Referring to Figure 26 , a battery pack 300 according to an embodiment of the present disclosure includes an assembly in which cylindrical battery cells 301 are electrically connected and a battery pack housing 302 for accommodating the assembly. The cylindrical battery cell 301 can be any one of the battery cells according to the above-described embodiments (variations). In the drawings, for the sake of simplicity of illustration, components such as bus bars, cooling units, and external terminals for electrically connecting the cylindrical battery cells 301 are not shown.

[0534] The battery pack 300 can be mounted on a vehicle. The vehicle can be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheel vehicle or a two-wheel vehicle.

[0535] Figure 27 is a diagram schematically showing a vehicle including a battery pack 300 according to an embodiment of the present disclosure.

[0536] Referring to Figure 27, a vehicle V according to an embodiment of the present disclosure includes a battery pack 300 according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, the vehicle V operates by receiving electric power from the battery pack 300.

[0537] According to the present disclosure, since the uncoated portions protruding from the upper and lower portions of the electrode assembly itself serve as electrode joints, the internal resistance of the battery cell can be reduced and the energy density can be increased.

[0538] According to another embodiment of the present disclosure, since the structure of the uncoated portion of the electrode assembly is improved, the electrode assembly does not interfere with the inner circumference of the battery can during the process of forming the curled portion of the battery can, so that a short circuit in the cylindrical battery cell caused by partial deformation of the electrode assembly can be prevented.

[0539] According to still another embodiment of the present disclosure, since the structure of the uncoated portion of the electrode assembly is improved, the uncoated portion can be prevented from being torn when the uncoated portion is bent, and the overlapping layers of the uncoated portion are sufficiently increased, thereby improving the welding strength.

[0540] According to still another embodiment of the present disclosure, since the structure of the uncoated portion adjacent to the core portion of the electrode assembly is improved, the cavity in the core portion of the electrode assembly can be prevented from being blocked when the uncoated portion is bent. Therefore, the electrolyte injection process and the process of welding the battery can (or riveting the terminal) and the current collector plate can be easily performed.

[0541] According to still another embodiment of the present disclosure, a cylindrical battery cell, a battery pack including the cylindrical battery cell, and a vehicle can be provided, and the structure of the cylindrical battery cell has a low internal resistance, prevents internal short circuits, and improves the welding strength between the current collector plate and the uncoated portion.

[0542] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, although indicating preferred embodiments of the present disclosure, are given by way of illustration only, because various changes and modifications within the scope of the present disclosure will become apparent to those skilled in the art from this detailed description.

[0543] Examples

[0544] (A-1) Preparation of the current collector

[0545] (1) Preparation of the current collector for the positive electrode

[0546] As shown in Table 1 below, a metal foil for the current collector made of aluminum and including an uncoated portion is prepared, and segments of Group 1 and Group 2 will be formed on the uncoated portion.

[0547] The length of the metal foil from the core to the outer periphery in the winding direction X is 4000 mm (B1 + B2 + B3), and the width in the winding axis direction is 75 mm. The metal foil is classified such that B1 is the core-side portion, B3 is the outer periphery portion, and B2 is the intermediate portion between the core-side portion and the outer periphery portion. The length of B1 is 350 mm, the length of B2 is 3500 mm, and the length of D3 is 150 mm.

[0548] A predetermined width of the metal foil from the second side to the first side is set as the positive electrode active material portion, and the remaining portion is set as the first portion as the uncoated portion. The heights of the core-side uncoated portion and the peripheral uncoated portion in the winding axis direction are less than the height of the intermediate uncoated portion.

[0549] (2) Preparation of the current collector for the negative electrode

[0550] The negative electrode current collector is prepared in the same manner as the positive electrode current collector, except that a copper thin film (10 μm thick) is used as the current collector and the width along the winding axis is 80 mm.

[0551] [Table 1]

[0552]

[0553] (B-1) Preparation of the current collector

[0554] (1) Preparation of the current collector for the positive electrode

[0555] As shown in Table 2 below, a metal foil (15 μm thick) made of aluminum and including an uncoated portion is prepared, and segments of Group 1 will be formed on the uncoated portion.

[0556] The length of the metal foil from the core to the outer periphery in the winding direction is 4000 mm (B1 + B2 + B3), and the width in the winding axis direction is mm. The metal foil is classified such that B1 is the core-side portion, B3 is the outer periphery portion, and B2 is the intermediate portion between the core-side portion and the outer periphery portion. The length of B1 is 350 mm, the length of B2 is 3500 mm, and the length of B3 is 150 mm.

[0557] A predetermined width of the metal foil from the second side to the first side is set as the positive electrode active material portion, and the remaining portion is set as the first portion as the uncoated portion. The heights of the core-side uncoated portion and the peripheral uncoated portion in the winding axis direction are less than the height of the intermediate uncoated portion.

[0558] (2) Preparation of the current collector for the negative electrode

[0559] The negative electrode current collector was prepared in the same manner as the positive electrode current collector, except that a copper film (10 μm thick) was used as the current collector and the width along the winding axis was 80 mm.

[0560] [Table 2]

[0561]

[0562] (2) Preparation of the negative electrode

[0563] Native graphite from soil with an average particle size (D 50 ) of 11 μm, carbon black, carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) were mixed with water at a weight ratio of 94:1.5:2:2.5 to prepare a slurry for the negative electrode active material layer, where the concentration of the remaining components except water was 50 wt%. Then, the slurry was coated onto the anode active material portion (lower sub-layer) of the surface of the above-prepared copper current collector using a slot die at a running speed of 40 m / min. The width of the electrode active material portion was 70 mm, and the width of the uncoated portion was 10 mm, where the width was along the winding axis direction. Based on the electrode area, the loading amount of the negative electrode active material was 16 mg / cm 2 . The copper film coated with the slurry for the negative electrode active material layer was passed through a hot air oven with a length of 60 m for drying, and the temperature of the oven was controlled to maintain 130 °C. Then, roll pressing was performed at a target thickness of 180 μm to obtain a negative electrode with a density of 3.45 g / cc.

[0564] Next, the middle uncoated portion was divided by laser slitting to set multiple segments as set in Table 1. Each cut valley had substantially the same height.

[0565] (3) Preparation of the positive electrode

[0566] Li(Ni 0.6 Mn 0.2 Co 0.2 )O 2 (NCM-622) as the positive electrode active material, carbon black as the conductive material, and polyvinylidene fluoride (PVdF) as the binder were added to water used as the dispersion medium at a weight ratio of 96:2:2 to prepare a slurry for the positive electrode active material. The slurry was coated on the active material portion of the surface of the aluminum current collector and dried, and rolled under the same conditions as the negative electrode to prepare the positive electrode. The width of the electrode active material portion was 65 mm, and the width of the uncoated portion was 10 mm, where the width was along the winding axis direction.

[0567] At this time, considering the theoretical discharge capacity of NMC 622, the positive electrode active material layer was adjusted so that the NP ratio of the battery was 1.18 (118%, approximately 27.7 cm2 ) To meet the NP ratio, the width of the positive electrode is made smaller than that of the negative electrode, and the positive electrode is located within the negative electrode based on the width.

[0568] Next, the middle uncoated portion is divided by laser grooving to set a plurality of segments as set in Table 1. Each cut valley portion has substantially the same height.

[0569] (4) Preparation of the separator

[0570] After adding about 5 wt% of polyvinylidene fluoride - hexafluoropropylene copolymer (PVdF - HFP) to tetrahydrofuran (THF), it is dissolved at a temperature of 50 °C for about 12 hours or longer to prepare a polymer solution. BaTiO powder with a particle size of about 400 nm 3 is added at a total solid content of 20 wt% and dispersed into the polymer solution to prepare a mixed solution (BaTiO 3 / PVdF - HFP = 80:20 (weight ratio)). The prepared mixed solution is coated on both surfaces of a polypropylene porous membrane using a doctor blade method. After coating, THF is dried to obtain the final organic / inorganic composite porous separator. The thickness of the final separator is about 30 μm. As a result of measurement with a porosimeter, the pore diameter and porosity of the final organic / inorganic composite porous membrane are 0.4 μm and 60 vol%, respectively.

[0571] (5) Preparation of the electrode assembly

[0572] The prepared negative electrode / separator / positive electrode are sequentially laminated and wound to prepare a wound - type electrode assembly. In Example A - 1, the end portion of the separator in the width direction is located at 30% (1.5 mm) of the height relative to the baseline of the smallest bending segment (Group 1) in the outer direction of the electrode assembly.

[0573] In Example A - 2, the end portion of the separator in the width direction is located at 10% (0.5 mm) of the height relative to the baseline of the smallest bending segment (Group 1) in the outer direction of the electrode assembly.

[0574] In Comparative Example A - 1, the end portion of the separator in the width direction is located at 50% of the height relative to the baseline of the smallest bending segment (Group 1) in the outer direction of the electrode assembly.

[0575] Meanwhile, in Example B - 1, the end portion of the separator in the width direction is located at 10% (0.6 mm) of the height based on the baseline of the smallest bending segment (Group 1) in the outer direction of the electrode assembly.

[0576] In Example B - 2, the end portion in the width direction of the separator is positioned corresponding to the baseline.

[0577] In Example B-3, the end of the separator in the width direction is located at 30% (1.8 mm) of the height based on the baseline of the minimum bending segment (Group 1) in the inner direction of the electrode group.

[0578] (6) Preparation of the battery (Type 4680)

[0579] The segments of Groups 1 to 7 exposed above and below the electrode assembly of Example A-1 are bent towards the core, and then the positive current collector and the negative current collector are welded to the upper bent surface and the lower bent surface, respectively. Then, the Figure 25 cylindrical battery shown is manufactured. That is, the electrode assembly welded with the positive current collector and the negative current collector is inserted into the battery case pre-installed with the external terminals, the positive current collector and the external terminals are welded, and the edge of the negative current collector is welded to the crimping part. Then, the battery case is introduced into the chamber of the electrolyte injection device, and the battery case is made to stand upright so that the opening of the battery case faces the direction opposite to gravity. Then, LiPF 6 is dissolved in an organic solvent in which ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) are mixed at a composition ratio of 1:2:1 (volume ratio) to a concentration of 1.0 M to prepare a non-aqueous electrolyte. Then, the electrolyte is injected through the opening of the battery case. Then, the electrode assembly is pressurized under the conditions of 800 kPa, boosting for 20 seconds, and holding for 150 seconds, and enters a vacuum under the conditions of -90 kPa, depressurizing for 20 seconds, and holding for 20 seconds. After the electrolyte impregnation process is completed, the opening of the battery case is sealed with a gasket using a sealant to complete the manufacture of the cylindrical battery.

[0580] The batteries of Example A-2, Comparative Example A-1, Example B-1, Example B-2, and Example B-3 are also manufactured by applying a manufacturing process substantially the same as the above.

[0581] (7) Evaluation of the electrolyte impregnation amount

[0582] The batteries of Example A-1, Example A-2, Comparative Example A-1, Example B-1, Example B-2, and Example B-3 are disassembled to obtain the positive electrode and the negative electrode, respectively. After that, a total of 9 points are cut off for the cathode and the anode, respectively, to obtain samples with a size of 10 cm 2 . When the electrodes are unfolded, three samples (#1 to #3) are collected in the region adjacent to the core of the electrode assembly, three samples (#7 to #9) are collected in the region adjacent to the outer periphery of the electrode assembly, and three samples (#4 to #6) are collected in the central region of the electrode based on the winding direction. When taking out three samples from each sampling region, one sample is taken from the lower end, the center, and the upper end of the active material layer in the direction of the winding axis. Figure 34The sampling area is shown. Here, #1, #4, and #7 are close to one end in the electrode width direction, #3, #6, and #9 are close to the other end in the electrode width direction, and #2, #5, and #8 are located in the middle area between these two regions. The sampling part of the sample can be referred to Figure 40 . However, Figure 40 only the sampling part based on Figure 7a is shown, and for the shapes and values other than the sampling part, please refer to [Table 1] and [Table 2] above.

[0583] Meanwhile, Figure 28 and Figure 29 show the electrolyte impregnation amounts at each position in the positive electrode and negative electrode according to Comparative Example A-1, Figure 30 and Figure 31 show the electrolyte impregnation amounts at each position in the positive electrode and negative electrode according to Example A-1, Figure 32 and Figure 33 show the electrolyte impregnation amounts at each position in the positive electrode and negative electrode according to Example A-2, Figure 34 and Figure 35 show the electrolyte impregnation amounts at each position in the positive electrode and negative electrode according to Example B-1, Figure 36 and Figure 37 show the electrolyte impregnation amounts at each position in the positive electrode and negative electrode according to Example B-2, and Figure 38 and Figure 39 show the electrolyte impregnation amounts at each position in the positive electrode and negative electrode according to Example B-3.

[0584] The electrolyte impregnation amount is determined by the difference between the weight of the control sample and the weight of the collected sample. The control sample is prepared in the same manner as the electrodes used in Example A-1, Example A-2, and Comparative Example A-1, and is obtained from the same sampling area. The control sample is not impregnated with electrolyte.

[0585] The average electrolyte impregnation amount of #1 to #9 is 60.3 mg in the electrode assembly of Example A-1, 59.6 mg in Example A-2, and 56.3 mg in Comparative Example A-1. The electrolyte impregnation amounts in Example A-1 and Example A-2 are higher than that in Comparative Example A-1.

[0586] In addition, the sum of the electrolyte impregnation amounts of the positive electrode sample and the negative electrode sample collected at #2 is 55.1 mg for the electrode assembly of Example A-1, 59 mg for the electrode assembly of Example A-2, and 47.7 mg for the electrode assembly of Comparative Example A-1. It can be seen that even near the core of the electrode assembly with a relatively low electrolyte impregnation amount, the electrolyte impregnation amounts of Example A-1 and Example A-2 are higher than that of Comparative Example A-1.

[0587] [Table 3]

[0588]

[0589] Figure 45 It is a graph showing the result of counting the number of segment laminations in the radial direction in the curved surface region F of the positive electrode formed on the top of the electrode assembly according to Example A-1. Substantially the same results are shown in the electrode assemblies according to Example A-2 and the examples of Group B below. The horizontal axis of the graph is the radius based on the center of the core, and the vertical axis of the graph is the number of segment laminations counted at each radius point. In the electrode assembly according to the embodiment, the lamination number uniform region is the radius section of the flat region on the graph. A lamination number reduction region appears outside the lamination number uniform region, where the number of segment laminations decreases as the radius increases. The lamination number reduction region b2 is the radius section where the number of segment laminations decreases as the radius of the electrode assembly increases. The lamination number uniform region b1 and the lamination number reduction region b2 are adjacent to each other in the radial direction and are complementary to each other.

[0590] [Table 4]

[0591]

[0592] The average electrolyte impregnation amount for each part in #1 to #9 is 69.6 mg in the electrode assembly of Example B-1, 70.1 mg in Example B-2, and 73.0 mg in Example B-3.

[0593] Furthermore, in the sampling region adjacent to the core of the electrode assembly, the sum of the electrolyte impregnation amounts of the positive electrode sample and the negative electrode sample taken at the center point (#2) of the active material portion in the winding axis direction is confirmed to be 54.3 mg in the electrode assembly of Example B-1, 52.4 mg in the electrode assembly of Example B-2, and 53.9 mg in the electrode assembly of Example B-3.

[0594] As confirmed above, when the end of the separator is placed close to the cut valley portion, the impregnation performance is favorable. Furthermore, since it is confirmed that the overall electrolyte impregnation performance is improved when the electrode assembly is arranged in the inner direction based on the baseline, as long as the insulation between the positive electrode and the negative electrode is ensured, the impregnation effect can also be improved by arranging the electrode assembly in the inner direction based on the baseline.

Claims

1. An electrode assembly, the electrode assembly comprising: a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate, wherein the first electrode plate, the second electrode plate, and the separator are wound together around an axis in one direction to have a plurality of winding turns, wherein each of the first electrode plate and the second electrode plate includes a first side and a second side, and the first side and the second side are disposed opposite to each other in the direction of the axis, wherein each of the first electrode plate and the second electrode plate further includes a first portion and a second portion, the first portion is an electrode active material portion coated with an electrode active material and extends from the second side towards the first side, wherein the second portion is an uncoated portion not coated with an electrode active material and extends from the first side towards the second side until the electrode active material portion of the first portion, wherein at least a partial region of the uncoated portion is divided into a plurality of segments by a cut groove having a predetermined depth, wherein the segments have first ends corresponding to the first side, wherein all or part of the segments are bent in the radial direction with respect to the axis at a bending point, and the bending point is a point below the first end in each segment, wherein, among the segments, the bent segments are referred to as bent segments, wherein, for the smallest bent segment having the smallest height among the bent segments, an end of the separator in the width direction is located within 50% of the height based on a baseline of the smallest bent segment in the outer direction of the electrode assembly, or, an end of the separator in the width direction is located within 30% of the height based on the baseline of the smallest bent segment in the inner direction of the electrode assembly, the baseline is a straight line extending in the winding direction (X) and having a height corresponding to the notch valley of the cut groove, and wherein when either the first electrode plate or the second electrode plate is a positive electrode plate and the other is a negative electrode plate, the width of the electrode active material portion of the positive electrode plate is equal to or less than the width of the electrode active material portion of the negative electrode plate.

2. The electrode assembly according to claim 1, wherein, either end of the separator is located between the bending point of each segment and the boundary between the first portion and the second portion.

3. The electrode assembly according to claim 1, wherein, either end of the separator is positioned such that the notch valley of the cut groove is not exposed by being covered by the separator.

4. The electrode assembly according to claim 2, wherein, the bending point is a specific point between the first end and the baseline, and the baseline is a straight line extending in the winding direction (X) and having a height corresponding to the notch valley of the cut groove.

5. The electrode assembly according to claim 1, wherein, in each of the first electrode plate and the second electrode plate, the length from the baseline to the first end of the segment can vary according to the winding direction.

6. The electrode assembly according to claim 1, wherein, in the bending section, the sections in the adjacent winding turns overlap continuously in the radial direction or in the direction opposite to the radial direction to form a surface area at the top or bottom of the electrode assembly in the winding axis direction, and wherein, when the shortest distance between the highest point of the surface area and the baseline is the height (HS) of the surface area, either end of the separator is located within 90% of the height (HS) of the surface area based on the baseline in the first side direction of the electrode assembly or below the baseline in the second side direction of the electrode assembly.

7. The electrode assembly according to claim 1, wherein, in the bending section, the sections in the adjacent winding turns overlap continuously in the radial direction or in the direction opposite to the radial direction to form a surface area at the top or bottom of the electrode assembly in the winding axis direction, and wherein, when the number of sections intersecting with a virtual line parallel to the winding axis direction at any radial position based on the center of the core of the electrode assembly in the surface area is defined as the number of section laminations at the corresponding radial position, the surface area includes a lamination number uniform area where the number of section laminations is uniform along the radius from the center of the core of the electrode assembly to the outer periphery and a lamination number decreasing area located outside the lamination number uniform area where the number of section laminations decreases towards the outer periphery.

8. The electrode assembly according to claim 7, wherein, in the lamination number uniform area, the number of section laminations is 10 or more.

9. The electrode assembly according to any one of claims 1 to 8, wherein, the uncoated portion includes a core side uncoated portion adjacent to the core of the electrode assembly, a peripheral uncoated portion adjacent to the outer peripheral surface of the electrode assembly, and an intermediate uncoated portion interposed between the core side uncoated portion and the peripheral uncoated portion, and wherein at least one of the core side uncoated portion and the peripheral uncoated portion has a relatively smaller length from the baseline to the first side than the intermediate uncoated portion.

10. The electrode assembly according to any one of claims 1 to 9, wherein, the core side uncoated portion has a relatively smaller length from the baseline to the first side than the intermediate uncoated portion and the peripheral uncoated portion.

11. The electrode assembly according to claim 9 or 10, wherein, the height of the core side uncoated portion corresponds to the baseline.

12. The electrode assembly according to any one of claims 9 to 11, wherein, the core side uncoated portion includes an uncoated portion located in the part of the electrode plate corresponding to the innermost winding turn of the electrode assembly, and wherein the peripheral uncoated portion includes an uncoated portion located in the part of the electrode plate corresponding to the outermost winding turn of the electrode assembly.

13. The electrode assembly according to any one of claims 9 to 12, wherein, All or at least part of the uncoated intermediate portion is divided into a plurality of segments.

14. The electrode assembly according to any one of claims 1 to 13, wherein, the distance between the bending point and the separator is 0.1 mm or more.

15. The electrode assembly according to any one of claims 1 to 14, wherein, the width of the electrode active material portion of the positive electrode plate is set within the width of the electrode active material portion of the negative electrode plate.

16. The electrode assembly according to claim 1, wherein, at least one of the first electrode plate and the second electrode plate has a sliding portion formed at one end in the width direction of the electrode active material portion.

17. The electrode assembly according to claim 1, wherein, the distance from the first end of the smallest bending segment to the baseline is 2 mm or more.

18. The electrode assembly according to claim 1, wherein, in the smallest bending segment, the length from the baseline to the bending line is equal to or longer than the length from the bending line to the first end, and wherein the bending point is the point at which the inclination angle of the tangent line in the portion generated by bending the segment toward the winding center by an external force starts to be less than or equal to 45°, and the inclination angle of the tangent line refers to the angle between the tangent line at the bending point and the plane perpendicular to the winding axis of the electrode assembly.

19. The electrode assembly according to claim 18, wherein, in the smallest bending segment, the length from the baseline to the bending line is equal to or less than the length from the bending line to the first end of the smallest bending segment, wherein the bending line is a line parallel to the baseline and including the bending point, and wherein the bending point is the point at which the inclination angle of the tangent line in the portion generated by bending the segment toward the winding center by an external force starts to be less than or equal to 45°, and the inclination angle of the tangent line refers to the angle between the tangent line at the bending point and the plane perpendicular to the winding axis of the electrode assembly.

20. The electrode assembly according to claim 1, wherein, the electrode assembly further includes a segment (segment A) having a height less than the smallest bending segment, or does not include any segment having a height less than the smallest bending segment such that the smallest bending segment is the smallest segment having the smallest height, and the height of the segment refers to the shortest length from the baseline to the first end of the segment.

21. The electrode assembly according to claim 20, wherein, compared with other segments among the plurality of segments, the segment A is arranged closer to the core.

22. The electrode assembly according to any one of claims 9 to 21, wherein, at least part of the uncoated intermediate portion is configured to have a height in the winding axis direction that gradually increases from the core to the outer periphery.

23. The electrode assembly according to any one of claims 1 to 22, wherein, each of the plurality of segments has a rectangular structure, a trapezoidal structure, a triangular structure, an equilateral quadrilateral structure, a semi-circular structure, or a semi-elliptical structure.

24. The electrode assembly according to any one of claims 1 to 23, wherein, each of the plurality of segments has a trapezoidal shape, and wherein the plurality of segments are configured such that the lower inner angles of the trapezoidal shape of the plurality of segments increase individually or in groups from the core part to the outer periphery.

25. The electrode assembly according to any one of claims 1 to 24, wherein, at least one of the height in the winding axis direction and the width in the winding direction of the plurality of segments gradually increases individually or in groups from the core part to the outer periphery.

26. The electrode assembly according to any one of claims 1 to 25, wherein, each of the plurality of segments satisfies at least one of the following conditions: a width condition of 1 mm to 6 mm in the winding direction; a height condition of 2 mm to 10 mm in the winding axis direction; and a separation distance condition of 0.05 mm to 1 mm in the winding direction.

27. The electrode assembly according to any one of claims 1 to 26, wherein, the plurality of segments satisfy a separation distance condition of 0.05 mm to 1 mm in the winding direction, the separation distance is defined as the distance between the corners of two adjacent segments, and circular reinforcing portions are formed at the corners of the adjacent segments.

28. The electrode assembly according to any one of claims 1 to 27, wherein, the plurality of segments form a plurality of segment groups from the core part to the outer periphery, and the segments belonging to the same segment group are the same in at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction.

29. The electrode assembly according to claim 28, wherein, when three segment groups that are continuously adjacent to each other in the radial direction of the electrode assembly have widths W1, W2, and W3 in the winding direction respectively, a combination including a segment group in which W3 / W2 is less than W2 / W1 is included.

30. The electrode assembly according to claim 28 or 29, wherein, the segments belonging to the same segment group are configured such that at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction gradually increases from the core part to the outer periphery along the winding direction.

31. The electrode assembly according to any one of claims 28 to 30, wherein, at least some of the plurality of segment groups are provided at the same winding turn of the electrode assembly.

32. The electrode assembly according to any one of claims 6 to 31, wherein, the uncoated portion on the core part side does not have the segment structure of the uncoated portion.

33. The electrode assembly according to any one of claims 6 to 32, wherein, the uncoated portion on the peripheral edge does not have the segment structure of the uncoated portion.

34. The electrode assembly according to any one of claims 1 to 33, wherein, the plurality of segments are bent toward the core part in the radial direction, and the plurality of bent segments overlap with the segments closer to the core part to form multiple layers.

35. The electrode assembly according to claim 34, Among them, the electrode assembly has a cavity formed in the core portion, and wherein the cavity is not closed by the plurality of segments bent toward the core portion.

36. The electrode assembly according to any one of claims 6 to 35, wherein, the radial length (R) of the uncoated portion on the core side and the height (H) of the innermost segment of the intermediate uncoated portion satisfy the formula H ≤ R.

37. The electrode assembly according to any one of claims 6 to 36, wherein, the peripheral uncoated portion is configured to have a height decreasing from the core portion to the outer periphery.

38. The electrode assembly according to claim 37, wherein, the height of the peripheral uncoated portion gradually decreases along the winding direction.

39. The electrode assembly according to any one of claims 6 to 38, wherein, the peripheral uncoated portion and the intermediate uncoated portion are divided into a plurality of segments, and wherein the plurality of segments included in the peripheral uncoated portion are configured such that at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction is larger than that of the plurality of segments included in the intermediate uncoated portion.

40. The electrode assembly according to any one of claims 1 to 39, wherein, the separator includes: a porous polymer substrate; and a porous coating located on at least one surface of the porous polymer substrate and containing inorganic particles and a binder polymer.

41. The electrode assembly according to claim 40, wherein, the inorganic particles include inorganic particles having a hydrophilic surface.

42. A cylindrical battery cell, the cylindrical battery cell comprises: the electrode assembly according to any one of claims 1 to 41; a battery can configured to accommodate the electrode assembly and electrically connected to one of the first electrode plate and the second electrode plate to have a first polarity; a sealing body configured to seal the open end of the battery can; and a terminal electrically connected to the other of the first electrode plate and the second electrode plate to have a second polarity and configured to have a surface exposed to the outside, wherein the separator includes: a porous polymer substrate; and a porous coating located on two surfaces of the porous polymer substrate and containing inorganic particles and a binder polymer.

43. The cylindrical battery cell according to claim 42, wherein, the uncoated portion as the second part includes an uncoated portion on the core side adjacent to the core of the electrode assembly, a peripheral uncoated portion adjacent to the outer periphery of the electrode assembly, and an intermediate uncoated portion interposed between the uncoated portion on the core side and the peripheral uncoated portion.

44. The cylindrical battery cell according to claim 43, wherein, in the winding axis direction, the peripheral uncoated portion has a relatively smaller height than the intermediate uncoated portion, wherein the battery can includes a crimped portion formed at an end of the battery can adjacent to the open end and press-fitted inwardly, and Wherein, the inner circumference of the curled edge portion facing the top edge of the electrode assembly is spaced apart from the peripheral uncoated portion at a predetermined interval.

45. The cylindrical battery cell according to claim 44, wherein, the press-in depth (D1) of the curled edge portion and the distance (D2) from the inner circumference of the battery can to the boundary point between the peripheral uncoated portion and the intermediate uncoated portion satisfy the formula D1 ≤ D2.

46. The cylindrical battery cell according to claim 44 or 45, the cylindrical battery cell further comprises: a current collector plate electrically connected to the intermediate uncoated portion; and an insulator configured to cover the current collector plate and having an edge inserted and fixed between the inner circumference of the curled edge portion and the current collector plate.

47. The cylindrical battery cell according to claim 46, wherein, the outermost diameter of the current collector plate and the intermediate uncoated portion is smaller than the minimum inner diameter of the inner circumference of the curled edge portion, and the diameter of the current collector plate is equal to or greater than the outermost diameter of the intermediate uncoated portion.

48. The cylindrical battery cell according to claim 46 or 47, wherein, the current collector plate is positioned higher than the bottom end of the curled edge portion.

49. The cylindrical battery cell according to any one of claims 43 to 48, wherein, the segments in at least a partial region of the intermediate uncoated portion are bent from the outer circumference toward the core portion, wherein the electrode assembly has a cavity formed in the core portion, and wherein the cavity is not closed by the bent structure of the intermediate uncoated portion.

50. The cylindrical battery cell according to claim 49, wherein, the intermediate uncoated portion includes a plurality of segments, and wherein the radial length (R) of the core-side uncoated portion and the height (H) of the innermost segment of the intermediate uncoated portion satisfy the formula H ≤ R.

51. The cylindrical battery cell according to claim 50, wherein, each of the plurality of segments has a rectangular structure, a trapezoidal structure, a triangular structure, an equilateral quadrilateral structure, a semi-circular structure, or a semi-elliptical structure.

52. The cylindrical battery cell according to claim 50 or 51, wherein, each of the plurality of segments satisfies at least one of the following conditions: a width condition of 1 mm to 6 mm in the winding direction; a height condition of 2 mm to 10 mm in the winding axis direction; and a separation distance condition of 0.05 mm to 1 mm in the winding direction.

53. The cylindrical battery cell according to any one of claims 42 to 52, wherein, a gap is provided between the cut valley portion of the segment of the electrode assembly and the active material layer.

54. The cylindrical battery cell according to claim 53, wherein, the gap is 0.2 mm to 4 mm.

55. The cylindrical battery cell according to any one of claims 50 to 54, wherein, the plurality of segments form a plurality of segment groups, Among them, segments belonging to the same segment group are the same as each other in at least one of the width in the winding direction, the height in the winding axis direction, and the separation distance in the winding direction, and Among them, at least one of the multiple segment groups constitutes the same winding turn of the electrode assembly.

56. The cylindrical battery cell according to any one of claims 50 to 55, Among them, the multiple segments form multiple segment groups, and Among them, when three segment groups that are continuously adjacent to each other in the radial direction of the electrode assembly have widths W1, W2, and W3 in the winding direction, respectively, a combination of segment groups including those in which W3 / W2 is less than W2 / W1 is included.

57. The cylindrical battery cell according to any one of claims 42 to 56, Among them, the sealing body includes a cover plate configured to seal the open end of the battery can, and a gasket configured to surround the edge of the cover plate and press against the top end of the battery can, and Among them, the terminal having the second polarity is the cover plate.

58. The cylindrical battery cell according to any one of claims 42 to 57, the cylindrical battery cell further includes: a current collector plate, the current collector plate being electrically connected to the uncoated portion of the second electrode plate having the first polarity and having an edge at least partially coupled to the side wall of the battery can, Among them, the sealing body includes a cover plate having no polarity and a gasket configured to surround the edge of the cover plate and press against the top end of the battery can, and Among them, the battery can includes a riveted terminal, the riveted terminal being installed to be insulated in a perforation formed in the central portion of the closed surface of the battery can and electrically connected to the first electrode plate to have the second polarity.

59. A battery pack, the battery pack including at least one battery cell according to any one of claims 42 to 58.

60. A vehicle, the vehicle including at least one battery pack according to claim 59.

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