Electrode assembly, cylindrical battery cell, battery pack including the same, and automobile

Abstract

The present invention discloses an electrode assembly, a cylindrical battery cell, a battery pack including the same, and an automobile. The electrode assembly is a jelly-roll-type electrode assembly having a structure in which a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates are wound in one direction. At least one of the first and second electrode plates includes an uncoated portion on a long edge thereof where an active material layer is not coated. At least a portion of the uncoated portion itself serves as an electrode tab. The uncoated portions include a core-side uncoated portion adjacent to the core of the electrode assembly, an outer-side 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 outer-side uncoated portion. Preferably, at least one of the core-side uncoated portion and the outer-side uncoated portion has a height in the winding axis direction that is relatively lower than that of the intermediate uncoated portion.

Description

[Technical Field]

[0001] The present invention relates to an electrode assembly, a cylindrical battery cell, a battery pack including the same, and an automobile. [Background technology]

[0002] Secondary batteries, which have high applicability to each product group and electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) and hybrid electric vehicles (HEVs), which are powered by electrical sources.

[0003] Such secondary batteries are attracting attention as a new energy source that not only has the primary advantage of dramatically reducing the use of fossil fuels, but also is environmentally friendly because they do not produce any by-products from energy use and can improve energy efficiency.

[0004] Currently, secondary batteries such as lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and nickel-zinc batteries are widely used. The operating voltage of such unit secondary battery cells, i.e., unit battery cells, is approximately 2.5V to 4.5V. Therefore, if a higher output voltage is required, a battery pack is constructed by connecting multiple battery cells in series. Alternatively, a battery pack may be constructed by connecting multiple battery cells in parallel according to the required charge / discharge capacity of the battery pack. Therefore, the number of battery cells included in the battery pack and the electrical connection configuration can be variously set depending on at least one of the required output voltage and charge / discharge capacity.

[0005] Meanwhile, known types of secondary battery cells include cylindrical, prismatic, and pouch-type battery cells. In the case of cylindrical battery cells, a separator, which is an insulator, is interposed between a positive electrode and a negative electrode, and the separator is wound up to form a jelly-roll-type electrode assembly. This jelly-roll-type electrode assembly is then inserted into a battery can to form a battery. Strip-shaped electrode tabs are connected to the uncoated portions of the positive and negative electrodes, respectively, and the electrode tabs electrically connect the electrode assembly to the electrode terminals exposed to the outside. For reference, the positive electrode terminal is the cap plate of the sealing body that seals the opening of the battery can, and the negative electrode terminal is the battery can. However, conventional cylindrical battery cells with this structure suffer from problems such as high resistance, large heat generation, and poor current collection efficiency due to current concentration at the strip-shaped electrode tabs connected to the positive electrode uncoated portion and / or negative electrode uncoated portion.

[0006] Resistance and heat generation are not major issues for small cylindrical battery cells with form factors such as 18650 and 21700. However, when the form factor of cylindrical battery cells is increased to apply them to electric vehicles, a large amount of heat is generated around the electrode tabs during the fast charging process, which can cause the cylindrical battery cell to catch fire.

[0007] To solve these problems, a cylindrical battery cell (so-called tab-less cylindrical battery cell) has been proposed, which has a structure in which positive and negative electrode uncoated areas are designed to be located at the upper and lower ends of a jelly-roll type electrode assembly, respectively, and current collecting plates are welded to these uncoated areas to improve current collection efficiency.

[0008] Figures 1 to 3 show the manufacturing process of a tabless cylindrical battery cell. Figure 1 shows the structure of the electrode plate, Figure 2 shows the electrode plate winding process, and Figure 3 shows the process of welding a current collector plate to the bent surface of the uncoated portion.

[0009] 1 to 3, the positive electrode plate 10 and the negative electrode plate 11 have a structure in which an active material 21 is coated on a sheet-shaped current collector 20, and include a plain portion 22 on one long side along the winding direction X.

[0010] The electrode assembly A is fabricated by sequentially stacking a positive electrode plate 10 and a negative electrode plate 11 together with two separators 12, as shown in Figure 2, and then winding the stack in one direction (X-axis direction). At this time, the uncoated portions of the positive electrode plate 10 and the negative electrode plate 11 are arranged in opposite directions. Here, the one direction (X-axis direction) refers to the winding direction around 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. Then, the current collector plates 30 and 31 are welded to the uncoated portions 10a and 11a, respectively.

[0012] No separate electrode tabs are attached to the positive electrode uncoated region 10a and the negative electrode uncoated region 11a, and current collector plates 30 and 31 are connected to external electrode terminals, forming a current path with a large cross-sectional area along the winding axis direction of electrode assembly A (see arrow), which has the advantage of reducing the resistance of the battery cell, since resistance is inversely proportional to the cross-sectional area of ​​the path through which current flows.

[0013] In a tabless cylindrical battery cell, in order to improve the welding characteristics between the uncoated portions 10a, 11a and the current collecting plates 30, 31, it is necessary to apply strong pressure to the welding points of the uncoated portions 10a, 11a to bend the uncoated portions 10a, 11a as flat as possible.

[0014] However, when the welded points of the uncoated portions 10a, 11a are bent, the patterns of the uncoated portions 10a, 11a may become irregularly distorted and deformed. In this case, the deformed portion may come into contact with the electrode plate of the opposite polarity, causing an internal short circuit or microcracks in the uncoated portions 10a, 11a. Furthermore, as the uncoated portion 32 adjacent to the core of the electrode assembly A is bent, it may block all or a significant portion of the cavity 33 in the core of the electrode assembly A. This creates a problem during the electrolyte injection process. The cavity 33 in the core of the electrode assembly A serves as a passage for injecting the electrolyte, and blocking this passage makes it difficult to inject the electrolyte. Furthermore, when the electrolyte injector is inserted into the cavity 33, it may interfere with the uncoated portion 32 near the core, causing the uncoated portion 32 to break.

[0015] In addition, the bent portions of the plain portions 10a and 11a where the current collector plates 30 and 31 are welded must be overlapped with no open spaces (gaps). This ensures sufficient welding strength and prevents the laser from penetrating into the electrode assembly A and melting the separator or active material, even when using cutting-edge technology such as laser welding.

[0016] Meanwhile, in a conventional table-less cylindrical battery cell, a positive electrode uncoated region 10a is formed entirely on the top of the electrode assembly A. Therefore, when the outer periphery of the upper end of the battery can is pressed inward to form a beading portion, the upper peripheral region 34 of the electrode assembly A is compressed by the battery can. This compression causes partial deformation of the electrode assembly A, which can cause the separator 12 to break and an internal short circuit. An internal short circuit in the battery can potentially lead to overheating or explosion of the battery.

[0017] Conventional separators incorporate a coating layer containing inorganic particles to improve the thermal shrinkage characteristics of the porous polymer substrate. However, these are single-sided inorganic-coated separators, in which the coating layer is applied to only one side of the porous polymer substrate. When these inorganic-coated separators face the electrodes in a jelly roll (J / R), one side is fabric and the other is an inorganic (ceramic) coating layer, resulting in asymmetric electrolyte impregnation characteristics. This asymmetric electrolyte impregnation poses management issues, such as the need to design the positive and negative electrodes to match the separator. Furthermore, the need for increased pressure / vacuum conditions when impregnating the electrolyte into the jelly roll increases costs, and performance can be compromised if the impregnation process is not performed properly.

[0018] In addition, conventional single-sided inorganic-coated separators have limited heat resistance because the fabric is exposed on one side of the separator, and they suffer from significant shrinkage at temperatures above 130°C, which can cause serious problems. As a result, when subjected to thermal shock (above 130°C), the separator shrinks, causing a short circuit in the internal electrodes, and when the temperature inside the cell rises due to an abnormal reaction (overcharging, external short circuit), the risk of fire increases.

[0019] In addition, in the case of non-notched jelly rolls, after assembly, the foil current collector is folded, forming a closed structure inside and outside, which interferes with the movement of electrolyte to the electrodes inside the jelly roll during injection, resulting in uneven electrolyte impregnation characteristics. This is thought to be due to the occurrence of uneven electrolyte impregnation paths during electrolyte impregnation. This leads to increased variation between batteries due to reduced impregnation uniformity, and the formation of an unstable solid electrolyte interface (SEI) layer, which increases resistance dispersion. Summary of the Invention [Problem to be solved by the invention]

[0020] The present invention was conceived in light of the above-mentioned background of the prior art, and aims to provide an electrode assembly having improved electrolyte impregnation characteristics.

[0021] Another object of the present invention is to provide an electrode assembly having an improved uncoated portion structure that can reduce stress applied to the uncoated portions exposed at both ends of the electrode assembly when the uncoated portions are bent.

[0022] Another object of the present invention is to provide an electrode assembly in which the electrolyte injection passage is not blocked even when the non-coating portion is bent.

[0023] Another object of the present invention is to provide an electrode assembly including a structure that can prevent the upper edge of the electrode assembly from coming into contact with the inner surface of the battery can when the upper end of the battery can is pushed in.

[0024] Another object of the present invention is to provide an electrode assembly having improved energy density and reduced resistance.

[0025] Yet another problem to be solved by the present invention is to provide a cylindrical battery cell including an electrode assembly with an improved structure, a battery pack including the same, and a vehicle including the battery pack.

[0026] The problems to be solved by the present invention are not limited to those mentioned above, and problems not mentioned will be clearly understood by those skilled in the art from the description of the invention below. [Means for solving the problem]

[0027] The present invention relates to an electrode assembly for an electrochemical device, in a first aspect, the electrode assembly including a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates, the first electrode plate, the second electrode plate, and the separator being wound in one direction around an axis to form a plurality of winding turns, the first electrode plate and the second electrode plate each independently include a first side portion and a second side portion, the first side portion and the second side portion being disposed on opposite sides in the axial direction; the first electrode plate and the second electrode plate each independently include a first portion and a second portion on at least one surface, the first portion being an electrode active material portion coated with an electrode active material and extending from the second side portion toward the first side portion; the second portion is a plain portion that is not coated with an electrode active material and extends from the first side portion toward the second side portion to the electrode active material portion of the first portion; At least a portion of the uncoated portion is divided into a plurality of sections by incised grooves of a predetermined depth, the segment has a first end coincident with a first side; All or at least a portion of the segment is bent radially relative to the axis at a bending point, which is a point in the segment below the first end, The folded portion of the segment is referred to as a folded portion, For the smallest bent segment having the smallest height among the bent segments, One widthwise end of the separator is positioned toward the outside of the electrode assembly at a distance less than 50% of the height of the minimum bend section from a reference line, or one widthwise end of the separator is positioned toward the inside of the electrode assembly at a distance within 30% of the height of the minimum bend section from a reference line, the reference line is a straight line extending in the winding direction X to a height corresponding to a notch valley of the cut groove, the first electrode plate is a positive electrode plate, the second electrode plate is a negative electrode plate, and the width of the electrode active material portion of the first electrode plate is equal to or narrower than the width of the electrode active material portion of the second electrode plate.

[0028] According to the second aspect of the present invention, either one end of the separation membrane is located between the bending point of each of the segments and the boundary line between the first portion and the second portion.

[0029] According to a third aspect of the present invention, in the first or second aspect, the separation film is arranged so that the notched valleys (or the like) of the cut grooves (or the like) are covered with the separation film and are not exposed.

[0030] According to a fourth aspect of the present invention, in the second or third aspect, the bending point is a point between the first end and a reference line, and the reference line is a straight line extending in the winding direction X to a height corresponding to the notch valley of the incision groove.

[0031] According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the segment (etc.) of the first electrode plate and the segment (etc.) of the second electrode plate each independently have a different distance from the reference line to the first end along the winding direction.

[0032] According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the folded segments of adjacent winding turns are continuously overlapped in a radial direction or an opposite direction to form a surface region at an upper end or a lower end of the winding axis direction of the electrode assembly, If the shortest distance between the highest point of the surface area and the reference line is taken as the height HS of the surface area, Either one end of the separator is located toward a first side of the electrode assembly within 90% of the height HS of the surface area relative to the reference line, or is located toward a second side of the electrode assembly below the reference line.

[0033] According to a seventh aspect of the present invention, in any one of the first to sixth aspects, adjacent winding turn segments among the folded segments are continuously overlapped in a radial direction or an opposite direction to form a surface region at an upper end or a lower end of the winding axis direction of the electrode assembly, When the number of segments intersecting a virtual line parallel to the winding axis direction at any radial position of the surface region relative to the center of the core of the electrode assembly is defined as the number of stacked segments at that radial position, the surface region includes a uniform stacking number section extending from the center to the outer periphery along the radius of the core of the electrode assembly, in which the number of stacked segments is the same, and a decreasing stacking number section located outside the uniform stacking number section, in which the number of stacked segments decreases toward the outer periphery.

[0034] According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the uniform stack number section has 10 or more stacked segments.

[0035] According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the uncoated portion includes a core-side uncoated portion adjacent to a core of the electrode assembly, an outer periphery-side uncoated portion adjacent to an outer periphery surface of the electrode assembly, and an intermediate uncoated portion interposed between the core-side uncoated portion and the outer periphery-side uncoated portion, At least one of the core-side uncoated portion and the outer-periphery-side uncoated portion has a relatively shorter distance from the reference line to the first side portion than the intermediate uncoated portion.

[0036] According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the core-side uncoated portion has a relatively shorter distance from the reference line to the first side portion than the intermediate uncoated portion and the outer periphery-side uncoated portion.

[0037] According to an eleventh aspect of the present invention, in the ninth or tenth aspect, the height of the core-side uncoated portion coincides with the reference line.

[0038] According to a twelfth aspect of the present invention, in any one of the ninth to eleventh aspects, the core-side uncoated portion includes an uncoated portion of an electrode plate portion corresponding to an innermost winding turn of the electrode assembly, The outer peripheral uncoated portion includes an uncoated portion of an electrode plate portion corresponding to the outermost winding turn of the electrode assembly.

[0039] According to a thirteenth aspect of the present invention, in any one of the ninth to twelfth aspects, the entire or at least a part of the intermediate uncoated portion is divided into a plurality of segments.

[0040] According to a 14th aspect of the present invention, in any one of the 1st to 13th aspects, the bending point and the separation membrane are spaced apart by 0.1 mm or more.

[0041] According to a 15th aspect of the present invention, in any one of the first to fourteenth aspects, the width of the electrode active material portion of the first electrode plate is arranged within the width of the electrode active material portion of the second electrode plate.

[0042] According to a 16th aspect of the present invention, in any one of the first to fifteenth aspects, a sliding portion is formed on one side end portion in the width direction of the electrode active material portion.

[0043] According to a 17th aspect of the present invention, in any one of the first to sixteenth aspects, the distance from the first end of the minimum bend segment to the reference line is 2 mm or more.

[0044] According to an 18th aspect of the present invention, in any one of the first to seventeenth aspects, in the minimum bending segment, the length from the reference line to the bending line is equal to or longer than the length from the bending line to the first end, The bending point is a point where the inclination of a tangent to the bending point begins to become 45° or less among the portions of the segment that are bent toward the winding center due to an external force, and the inclination of the tangent refers to the angle between the tangent to the bending point and a plane perpendicular to the winding axis of the electrode assembly.

[0045] According to a 19th aspect of the present invention, in the 18th aspect, in the minimum bent segment, the length from the reference line to the bent line based on the bent line is equal to or shorter than the length from the bent line to the first end of the segment, The bending line refers to a line that includes a bending point and is horizontal to the reference line. The bending point is a point where the inclination of a tangent to a portion of the segment that is bent toward the winding center due to an external force begins to become 45° or less. The inclination of the tangent refers to the angle between the tangent to the bending point and a plane perpendicular to the winding axis of the electrode assembly.

[0046] According to the 20th aspect of the present invention, in any one of the 1st to 19th aspects, the electrode assembly further includes a segment (segment A) having a height lower than the minimum bent segment, or does not include a segment having a height lower than the minimum bent segment, and the minimum bent segment becomes the minimum segment, and the height of the segment means the shortest distance from the reference line to the first end of the segment.

[0047] According to a 21st aspect of the present invention, in the 20th aspect, the segment piece A is arranged closer to the core portion than the other segment pieces among the plurality of segment pieces.

[0048] According to a 22nd aspect of the present invention, in any one of the 9th to 21st aspects, the height of at least a portion of the intermediate uncoated portion increases stepwise from the core side to the outer periphery side in the direction of the winding axis.

[0049] According to a 23rd aspect of the present invention, in any one of the 1st to 22nd aspects, each of the plurality of segments has a rectangular, trapezoidal, triangular, parallelogram, semicircular or semielliptical structure.

[0050] According to the 24th aspect of the present invention, in any one of the 1st to 23rd aspects, each of the plurality of segments is trapezoidal, and the lower interior angle of the trapezoid increases from the core side to the outer periphery side of the plurality of segments, individually or in groups.

[0051] According to the 25th aspect of the present invention, in any one of the first to 24th aspects, at least one of the height in the winding axis direction and the width in the winding direction of the plurality of segments increases stepwise from the core side to the outer periphery side in the winding direction, individually or in groups.

[0052] According to a 26th aspect of the present invention, in any one of the first to 25th aspects, each of the plurality of segments satisfies at least one of the following conditions: a width of 1 mm to 6 mm in the winding direction, a height of 2 mm to 10 mm in the winding axial direction, and a spacing pitch of 0.05 mm to 1 mm in the winding direction.

[0053] According to the 27th aspect of the present invention, in any one of the 1st to 26th aspects, the plurality of segments satisfy a separation pitch condition of 0.05 mm to 1 mm in the winding direction, the separation pitch is determined by the distance between the corners of two adjacent segments, and round reinforcement portions are further provided at the corners of the adjacent segments.

[0054] According to the 28th aspect of the present invention, in any one of the 1st to 27th aspects, the plurality of segment pieces form a plurality of segment piece groups from the core side toward the outer periphery side, and segment pieces belonging to the same segment piece group have at least one of the same width in the winding direction, height in the winding axial direction, and separation pitch in the winding direction.

[0055] According to the 29th aspect of the present invention, in the 28th aspect, when the winding direction widths of three consecutively adjacent segment groups in the radial direction of the electrode assembly are W1, W2 and W3, respectively, the combination of segment groups is included in which W3 / W2 is smaller than W2 / W1.

[0056] According to the 30th aspect of the present invention, in the 28th or 29th aspects, the segments belonging to the same segment group have at least one of their width in the winding direction, their height in the winding axial direction, and their separation pitch in the winding direction gradually increase in the winding direction from the core side to the outer periphery side.

[0057] According to a 31st aspect of the present invention, in any one of the 28th to 30th aspects, at least some of the plurality of segment groups are arranged in the same winding turn of the electrode assembly.

[0058] According to a 32nd aspect of the present invention, in any one of the 6th to 31st aspects, the core-side uncoated portion does not have a divided uncoated portion structure.

[0059] According to a 33rd aspect of the present invention, in any one of the 6th to 32nd aspects, the outer periphery uncoated portion does not have a divided uncoated portion structure.

[0060] According to the 34th aspect of the present invention, in any one of the 1st to 33rd aspects, the plurality of segments are bent radially toward the core, and the bent segments overlap with the segments closer to the core portion.

[0061] According to a 35th aspect of the present invention, in the 34th aspect, a cavity is provided in the core of the electrode assembly, and the cavity is not closed by the plurality of divided pieces bent toward the core side.

[0062] According to a 36th aspect of the present invention, in any one of the 6th to 35th aspects, 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 relational expression H≦R.

[0063] According to a 37th aspect of the present invention, in any one of the 6th to 36th aspects, the height of the outer periphery uncoated portion decreases from the core side toward the outer periphery in the winding direction.

[0064] According to a 38th aspect of the present invention, in the 37th aspect, the height of the outer circumferential uncoated portion decreases stepwise in the winding direction.

[0065] According to a 39th aspect of the present invention, in any one of the 6th to 38th aspects, the outer circumferential uncoated portion and the intermediate uncoated portion are divided into a plurality of segments, The plurality of segments included in the outer plain portion have at least one of a width in the winding direction, a height in the winding axial direction, and a spacing pitch in the winding direction that is larger than the plurality of segments included in the middle plain portion.

[0066] According to a 40th aspect of the present invention, in any one of the 1st to 39th aspects, the separation membrane includes a porous polymer substrate and a porous coating layer located on at least one surface of the porous polymer substrate, the porous coating layer including inorganic particles and a binder polymer.

[0067] According to a 41st aspect of the present invention, in the 40th aspect, the inorganic particles include inorganic particles whose surfaces have hydrophilic properties.

[0068] A forty-second aspect of the present invention relates to a cylindrical battery cell, the cylindrical battery cell comprising: an electrode assembly; a battery can that houses the electrode assembly and is electrically connected to one of the first electrode plate and the second electrode plate to have a first polarity; a sealing body that seals the open end of the battery can; a terminal electrically connected to the other of the first electrode plate and the second electrode plate, the terminal having a surface exposed to the outside and a second polarity; The separator includes a porous polymer substrate and porous coating layers positioned on both sides of the porous polymer substrate and containing inorganic particles and a binder polymer, and the electrode assembly is one of the first to forty-first aspects.

[0069] According to the 43rd aspect of the present invention, in the 42nd aspect, the uncoated portion which is the second portion includes a core-side uncoated portion adjacent to the core portion, an outer-periphery-side uncoated portion adjacent to the outer periphery, and an intermediate uncoated portion located between the core-side uncoated portion and the outer-periphery-side uncoated portion.

[0070] According to a 44th aspect of the present invention, in the 43rd aspect, the outer circumferential uncoated portion has a height in the winding axis direction that is relatively lower than that of the intermediate uncoated portion, the battery can has a beading portion pressed inward at an end adjacent to the open end, The inner circumferential surface of the beading portion facing the upper edge of the electrode assembly is spaced apart from the outer circumferential uncoated portion by a predetermined distance.

[0071] According to a 45th aspect of the present invention, in the 44th aspect, the pressing depth D1 of the beading portion and the distance D2 from the inner peripheral surface of the battery can to the boundary point between the outer uncoated portion and the intermediate uncoated portion satisfy the relational expression D1≦D2.

[0072] According to a 46th aspect of the present invention, there is provided the electric wiring board according to the 44th or 45th aspect, comprising: a current collector plate electrically connected to the intermediate plain portion; and

[0073] The current collector plate may further include an insulator covering the current collector plate, the peripheral edge of which is interposed and fixed between the inner peripheral surface of the beading portion and the current collector plate.

[0074] According to the 47th aspect of the present invention, in the 46th aspect, the outermost diameters of the current collecting plate and the intermediate plain portion are smaller than the smallest inner diameter of the inner surface of the beading portion, and the diameter of the current collecting plate is the same as or larger than the outermost diameter of the intermediate plain portion.

[0075] According to a 48th aspect of the present invention, in the 46th or 47th aspect, the current collector plate is positioned higher than a lower end of the beading portion.

[0076] According to the 49th aspect of the present invention, in any one of the 43rd to 48th aspects, a divided piece of at least a portion of the intermediate plain portion is bent from the outer periphery side to the core side, a cavity is provided in the core of the electrode assembly, and the cavity is not blocked by the bent structure of the intermediate plain portion.

[0077] According to the 50th aspect of the present invention, in the 49th aspect, the intermediate uncoated portion includes a plurality of segments, and the radial length R of the core-side uncoated portion and the height H of the segment located at the innermost position of the intermediate uncoated portion satisfy the relation H≦R.

[0078] According to a 51st aspect of the present invention, in the 50th aspect, each of the plurality of segments has a rectangular, trapezoidal, triangular, parallelogram, semicircular or semi-elliptical structure.

[0079] According to a 52nd aspect of the present invention, in the 50th or 51st aspect, each of the plurality of segments satisfies at least one of the following conditions: a width of 1 mm to 6 mm in the winding direction, a height of 2 to 10 mm in the winding axial direction, and a spacing pitch of 0.05 to 1 mm in the winding direction.

[0080] According to a 53rd aspect of the present invention, in any one of the 42nd to 52nd aspects, a gap is provided between the notched valley of the segment of the electrode assembly and the active material layer.

[0081] According to a 54th aspect of the present invention, in the 53rd aspect, the gap is 0.2 mm to 4 mm.

[0082] According to a 55th aspect of the present invention, in any one of the 50th to 54th aspects, the plurality of segments form a plurality of groups, The segments belonging to each group are identical in at least one of the width in the winding direction, the height in the winding axial direction, and the separation pitch in the winding direction, At least one of the plurality of groups constitutes the same winding turn of the electrode assembly.

[0083] According to a 56th aspect of the present invention, in any one of the 50th to 55th aspects, the plurality of segments form a plurality of groups, When the winding direction widths of three adjacent segment groups in the radial direction of the electrode assembly are W1, W2 and W3, respectively, the combination includes a combination of segment groups in which W3 / W2 is smaller than W2 / W1.

[0084] According to a 57th aspect of the present invention, in any one of the 42nd to 56th aspects, the sealed body includes a cap plate that seals the open end of the battery can, and a gasket that covers the outer periphery of the cap plate and is crimped to the upper end of the battery can, and the terminal having the second polarity is the cap plate.

[0085] According to a 58th aspect of the present invention, in any one of the 42nd to 57th aspects, the battery further includes a current collector plate electrically connected to an uncoated portion of the second electrode plate having the first polarity, and at least a part of an outer periphery of the current collector plate being joined to a side wall of the battery can, the sealing body includes a non-polar cap plate and a gasket that encloses the outer periphery of the cap plate and is crimped onto the upper end of the battery can; The battery can includes a rivet terminal insulatively attached to a through-hole formed in a center of a closed surface, electrically connected to the first electrode plate, and carrying the second polarity.

[0086] A fifty-ninth aspect of the present invention relates to a battery pack, the battery pack including the battery cell according to any one of the forty-second to fifty-eighth aspects.

[0087] A sixtieth aspect of the present invention relates to a motor vehicle, the motor vehicle including at least one battery pack according to the fifty-ninth aspect. [Effects of the Invention]

[0088] According to one aspect of the present invention, the uncoated portions protruding from the upper and lower portions of the electrode assembly are used as electrode tabs, thereby reducing the internal resistance of the battery cell and increasing the energy density.

[0089] According to another aspect of the present invention, by improving the structure of the uncoated portion of the electrode assembly, interference between the electrode assembly and the inner surface of the battery can does not occur during the process of forming the beading portion of the battery can, thereby preventing an internal short circuit in a cylindrical battery cell due to partial deformation of the electrode assembly.

[0090] According to yet another aspect of the present invention, the structure of the uncoated portion of the electrode assembly is improved to prevent the uncoated portion from tearing when being bent, and the number of overlapping layers of the uncoated portion is sufficiently increased to improve welding strength.

[0091] According to yet another aspect of the present invention, by improving the structure of the uncoated portion adjacent to the core of the electrode assembly, it is possible to prevent the cavity in the core of the electrode assembly from being blocked when the uncoated portion is bent, thereby facilitating the electrolyte injection process and the welding process of the battery can and the current collector plate.

[0092] According to yet another aspect of the present invention, it is possible to provide a cylindrical battery cell having a structure in which internal resistance is low, internal short circuits are prevented, and welding strength between a current collector plate and an uncoated portion is improved, as well as a battery pack and a vehicle including the same.

[0093] The present invention also provides various other effects, which will be described later with reference to the embodiments, but explanations of effects that can be easily inferred by ordinary skilled artisans will be omitted.

[0094] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to only the matters described in the drawings. [Brief explanation of the drawings]

[0095] [Figure 1] 1 is a plan view showing the structure of an electrode plate used in manufacturing a conventional tabless cylindrical battery cell. [Figure 2] 1A and 1B are diagrams illustrating a winding process of an electrode plate of a conventional tabless cylindrical battery cell. [Figure 3] 10A and 10B are views showing a process of welding a current collector plate to a bent surface of a non-coating portion in a conventional tabless cylindrical battery cell. [Figure 4] FIG. 1 is a plan view showing the structure of an electrode plate according to a first embodiment of the present invention. [Figure 5] FIG. 6 is a plan view showing the structure of an electrode plate according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a plan view showing the structure of an electrode plate according to a third embodiment of the present invention. [Figure 7a] FIG. 10 is a plan view showing the structure of an electrode plate according to a fourth embodiment of the present invention. [Figure 7b] FIG. 7b is an enlarged view showing the cross-section of FIG. 7a in more detail. [Figure 7c] FIG. 7b is an enlarged view showing the cross-section of FIG. 7a in more detail. [Figure 8] 10 is a diagram illustrating definitions of width, height, and spacing pitch of segments according to an embodiment of the present invention. [Figure 9a] FIG. 10 is a plan view showing the structure of an electrode plate according to a fifth embodiment of the present invention. [Figure 9b]FIG. 9b is an enlarged view showing the cross-section of FIG. 9a in more detail. [Figure 9c] FIG. 9b is an enlarged view showing the cross-section of FIG. 9a in more detail. [Figure 10] 10 is a diagram illustrating definitions of width, height, and spacing pitch of segments according to an embodiment of the present invention. [Figure 11] FIG. 1 is a cross-sectional view of a jelly-roll type electrode assembly in which the electrode plates of the first embodiment are applied to a first electrode plate (positive electrode plate) and a second electrode plate (negative electrode plate), taken along the Y-axis direction (winding axis direction). [Figure 12] FIG. 10 is a cross-sectional view of a jelly-roll type electrode assembly in which the electrode plates of the second embodiment are applied to the first electrode plate (positive electrode plate) and the second electrode plate (negative electrode plate), taken along the Y-axis direction (winding axis direction). [Figure 13] FIG. 10 is a cross-sectional view of a jelly-roll type electrode assembly in which any one of the electrode plates of the third to fifth embodiments (modifications thereof) is used as the first electrode plate (positive electrode plate) and the second electrode plate (negative electrode plate) taken along the Y-axis direction (winding axis direction). [Figure 14] 10 is a cross-sectional view of an electrode assembly according to another embodiment of the present invention taken along the Y-axis direction (winding axis direction). [Figure 15] 10 is a cross-sectional view of an electrode assembly according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction). [Figure 16] 10 is a cross-sectional view of an electrode assembly according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction). [Figure 17] 2 is a cross-sectional view of a cylindrical battery cell according to an embodiment of the present invention taken along a Y-axis direction. FIG. [Figure 18] FIG. 4 is a cross-sectional view of a cylindrical battery cell according to another embodiment of the present invention taken along the Y-axis direction. [Figure 19] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention, taken along the Y-axis direction. [Figure 20] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention taken along the Y axis. [Figure 21] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention taken along the Y axis. [Figure 22] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention taken along the Y axis. [Figure 23] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention taken along the Y axis. [Figure 24] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention taken along the Y axis. [Figure 25] FIG. 10 is a cross-sectional view of a cylindrical battery cell according to yet another embodiment of the present invention taken along the Y axis. [Figure 26] 1 is a diagram illustrating a schematic configuration of a battery pack according to an embodiment of the present invention; [Figure 27] 1 is a schematic diagram of a vehicle including a battery pack according to an embodiment of the present invention; [Figure 28] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the positive electrode according to Comparative Example A-1. [Figure 29] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the negative electrode according to Comparative Example A-1. [Figure 30] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the positive electrode according to Example A-1. [Figure 31] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the negative electrode according to Example A-1. [Figure 32] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the positive electrode according to Example A-2. [Figure 33] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the negative electrode according to Example A-2. [Figure 34] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the positive electrode according to Example B-1. [Figure 35] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the negative electrode according to Example B-1. [Figure 36]FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the positive electrode according to Example B-2. [Figure 37] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the negative electrode according to Example B-2. [Figure 38] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the positive electrode according to Example B-3. [Figure 39] FIG. 10 is a diagram showing the amount of impregnated electrolyte at each position on the electrode in the negative electrode according to Example B-3. [Figure 40] FIG. 2 is a diagram showing the positions where impregnated samples were collected in each of the comparative example and the example. [Figure 41] 4 is a diagram illustrating a comparison of the width of a positive electrode active material portion and the width of a negative electrode active material portion in an electrode assembly according to an embodiment of the present invention; FIG. [Figure 42] 10 is a diagram illustrating a state in which a segment of an uncoated portion is folded in an electrode assembly according to an embodiment of the present invention; [Figure 43] 10 is a schematic diagram showing a cross section of a bent surface region formed by bending a segment toward the core of the electrode assembly. FIG. [Figure 44] 1 is a perspective view schematically illustrating an electrode assembly having a bent surface region formed thereon; [Figure 45] 10 is a graph showing the results of counting the number of stacked pieces along the radial direction in a folded surface region of a positive electrode formed on an upper portion of an electrode assembly according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0096] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in the specification and claims should not be construed as being limited to their ordinary and dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best explain the invention.

[0097] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0098] In addition, to facilitate understanding of the invention, the accompanying drawings may not be drawn to scale, and the dimensions of some components may be exaggerated. In addition, the same reference numerals may be used to refer to the same components in different embodiments.

[0099] For ease of explanation, in this specification, the direction along the length of the winding shaft of the electrode assembly wound into a jelly roll is referred to as the axial direction (Y-axis direction). Furthermore, the direction surrounding the winding shaft is referred to as the circumferential direction or outer circumferential direction (X-axis direction). Furthermore, the direction approaching or moving away from the winding shaft is referred to as the radial direction or radial direction (Z-axis direction). Of these, the direction approaching the winding shaft is particularly referred to as the centripetal direction, and the direction moving away from the winding shaft is particularly referred to as the centrifugal direction.

[0100] First, an electrode assembly according to an embodiment of the present invention will be described.

[0101] The electrode assembly includes a first electrode plate, a second electrode plate, and a separator interposed between the first and second electrode plates, and the first electrode plate, the second electrode plate, and the separator are wound in one direction around an axis to form a plurality of winding turns. The first electrode plate and the second electrode plate each include a first side portion and a second side portion, and the first side portion and the second side portion are disposed on opposite sides in the axial direction.

[0102] In one embodiment of the present invention, one of the first electrode plate and the second electrode plate is a positive electrode plate, and the other is a negative electrode plate.

[0103] In one embodiment of the present invention, the first and second electrode plates may be rectangular sheets having an aspect ratio of more than 1. In this case, both ends of the width of each electrode plate correspond to a first side portion and a second side portion.

[0104] FIG. 4 is a plan view showing the structure of the electrode plate 40 according to the first embodiment of the present invention.

[0105] Referring to Figure 4, the second side is a side formed along the bottom end of the electrode active material part 42 in the winding axis (Y axis) direction, and the first side is a side formed along the top end of the plain part 43 in the winding axis (Y axis) direction.

[0106] The first and second electrode plates each independently include a first portion, which is an electrode active material portion coated with an electrode active material, on at least one or both sides. The first portion extends a predetermined length from the second side toward the first side. FIG. 4 is a diagram showing the shape of the electrode plate before the electrode assembly is wound up. Referring to this, the electrode active material portion may have a constant width along the entire length of the electrode plate in the axial direction, from the second side to the beginning of the uncoated portion.

[0107] The second portion is a plain portion that is not coated with an electrode active material. The second portion forms an electrode tab and extends from the first side portion toward the second side portion to the electrode active material portion of the first portion.

[0108] In one embodiment of the present invention, at least a portion of the uncoated portion is divided into a plurality of segments by incised grooves having a predetermined depth.

[0109] The segment has a first end corresponding to a first side. In one embodiment of the present invention, all or at least a portion of the segment may be bent radially in the radial direction (toward the winding center) of the electrode assembly or in the direction opposite to the radial direction at a bending point, which is a point in the segment below the first end. In a specific embodiment, the bending point may be a predetermined point between the first end and a reference line. In one embodiment of the present invention, the reference line refers to an imaginary straight line extending in the winding direction X to a height corresponding to the notch valley of the cutting groove.

[0110] In this way, in the current collector according to one embodiment of the present invention, the uncoated portion includes a plurality of segments, and the separator is disposed so that the notched valleys of the incision grooves between the segments are covered by the separator and not exposed, or if the separator is disposed below the reference line, the distance between one end of the separator and the reference line may be limited to a predetermined range. Such separator arrangement will be described in detail below.

[0111] In one embodiment of the present invention, the first ends of the segments may have different heights, the shapes of the incision grooves may be different, and the heights of the notch valleys of the incision grooves may also be different. That is, the shapes and sizes of the segments and the shapes and sizes of the incision grooves may be different.

[0112] Meanwhile, the height of the division segment may be defined as the axial distance (C2, D2) from the notch valley of the incision groove defining the division segment to the first end of the division segment. If the heights of the notch valleys of the incision grooves on both sides of the division segment are different, the height of the division segment may be defined as the axial distance from a position corresponding to the average height of the notch valleys of the incision grooves on both sides to the first end of the division segment.

[0113] On the other hand, in one embodiment of the present invention, the reference line is an imaginary straight line extending in the winding direction X at a height corresponding to the notched valley of the cut groove.

[0114] The first and second electrode plates may each independently include a current collector that is a conductive thin film and an active material layer disposed on one or both sides of the current collector, the active material layer forming a first portion of the electrode plate.

[0115] The sheet-shaped first and second electrode plates may have an aspect ratio of greater than 1. In this case, the uncoated portion may be formed on a long side edge in the winding direction of at least one of the first and second electrode plates, and at least a portion of the uncoated portion may be used as an electrode tab.

[0116] In one embodiment of the present invention, the uncoated portion includes a core-side uncoated portion adjacent to the core of the electrode assembly, an outer-periphery-side 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 outer-periphery-side uncoated portion.

[0117] Preferably, at least one of the core-side uncoated portion and the outer-periphery-side uncoated portion may be relatively lower in height than the intermediate uncoated portion.

[0118] Meanwhile, for convenience of explanation, "height" herein may refer to the distance (length) from a predetermined position in the winding direction X to the first side in the axial direction. When describing the height of the plain portion / notch valley in this specification, the relative value of the height measured at different positions in the winding direction is more meaningful than the absolute value of the height. Therefore, when measuring the height of the plain portion / notch valley, the definition of a reference line (zero point) for the height measurement may be omitted. In one embodiment of the present invention, the height of the plain portion may be a relative distance at a specific point based on an arbitrary perpendicular line to the winding axial direction. For example, the reference line (zero point) for the height measurement may be the second side.

[0119] On the other hand, more specifically, in the height of the plain portion, in the section where no dividing piece is formed, it means the distance to the first side, and in the section where a dividing piece is formed, the first side means the position corresponding to the first end of the dividing piece, and the part that forms the incision groove between the dividing pieces is not taken into consideration when measuring the height of the plain portion in the section where a dividing piece is formed.

[0120] The height of the notch valley is measured based on the lowest part of the cut groove.

[0121] Referring to FIG. 4, the electrode plate 40 of the first embodiment includes a current collector 41 made of metal foil and an electrode active material portion 42. The metal foil may be aluminum or copper, and is appropriately selected depending on the polarity of the electrode plate 40. An electrode active material layer is formed on at least one surface of the current collector 41, and an uncoated portion 43 is disposed on the long edge of the current collector in the winding direction X. The uncoated portion 43 is an area that is not coated with an active material. An insulating coating layer 44 may be formed at the boundary between the electrode active material portion 42 and the uncoated portion 43. The insulating coating layer 44 is formed so that at least a portion of the insulating coating layer 44 overlaps the boundary between the active material portion 42 and the uncoated portion 43. The insulating coating layer 44 includes a polymer resin and may include an inorganic material such as Al2O3.

[0122] The uncoated portion 43 includes a core-side uncoated portion B1 adjacent to the core side of the electrode assembly, an outer-periphery-side uncoated portion B3 adjacent to the outer periphery of the electrode assembly, and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the outer-periphery-side uncoated portion B3.

[0123] When each electrode plate 40 is wound into a jelly-roll-type electrode assembly, the core-side uncoated region B1, the outer-periphery uncoated region B3, and the intermediate uncoated region B2 may be defined as the uncoated region adjacent to the core side, the uncoated region adjacent to the outer periphery, and the uncoated region excluding these, respectively. The boundary between the core-side uncoated region B1 and the intermediate uncoated region B2 may be appropriately defined as a point where the height (or variation pattern) of the uncoated region substantially changes from the core side to the outer periphery of the electrode assembly, or as a predetermined percentage point based on the radius of the electrode assembly (e.g., 5%, 10%, 15% of the radius). The boundary between the intermediate uncoated region B2 and the outer-periphery uncoated region B3 may be defined as a point where the height (or variation pattern) of the uncoated region substantially changes from the outer periphery to the core side of the electrode assembly, or as a predetermined percentage point based on the radius of the electrode assembly (e.g., 85%, 90%, 95% of the radius). Once the boundaries between the core-side uncoated area B1 and the intermediate uncoated area B2 and the boundary between the intermediate uncoated area B2 and the outer-side uncoated area B3 are identified, the intermediate uncoated area B2 can be automatically identified. If only the boundary between the core-side uncoated area B1 and the intermediate uncoated area B2 is identified, the boundary between the intermediate uncoated area B2 and the outer-side uncoated area B3 can be appropriately selected as a point near the outer periphery of the electrode assembly. Conversely, if only the boundary between the intermediate uncoated area B2 and the outer-side uncoated area B3 is identified, the boundary between the core-side uncoated area B1 and the intermediate uncoated area B2 can be appropriately selected as a point near the core side of the electrode assembly. In the first embodiment, the height of the uncoated area 43 is not constant but varies relatively in the winding direction X. That is, the height (length in the Y-axis direction) of the outer-side uncoated area B3 is relatively lower than that of the core-side uncoated area B1 and the intermediate uncoated area B2.

[0124] Meanwhile, in one embodiment of the present invention, the width of the electrode active material portion in the direction of the short side of the current collector may be 50 mm to 120 mm, and the length of the electrode active material portion in the direction of 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%.

[0125] FIG. 5 is a plan view showing the structure of an electrode plate 45 according to a second embodiment of the present invention.

[0126] Referring to FIG. 5, the electrode plate 45 of the second embodiment differs from the first embodiment only in that the height of the outer uncoated portion B3 gradually decreases toward the outer periphery, and the other configurations are substantially the same.

[0127] In one modified embodiment, the outer peripheral uncoated portion B3 can be modified to have a stepped shape (see dotted lines) in which the height decreases stepwise. In one embodiment of the present invention, at least a portion of the uncoated portion of the electrode plate according to the second embodiment is divided into a plurality of segments by incision grooves of a predetermined depth (not shown).

[0128] FIG. 6 is a plan view showing the structure of an electrode plate 50 according to a third embodiment of the present invention.

[0129] 6, in the electrode plate 50 of the third embodiment, the heights of the core-side uncoated portion B1 and the outer-side uncoated portion B3 are relatively lower than the middle uncoated portion B2. The heights of the core-side uncoated portion B1 and the outer-side uncoated portion B3 may be the same or different.

[0130] Preferably, the height of the middle uncoated portion B2 may be in a stepped shape that increases stepwise from the core side toward the outer periphery side.

[0131] Patterns 1 to 7 are obtained by dividing the intermediate plain portion B2 around the positions where the height of the plain 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 maximize stress distribution during the folding process of the plain portion 43. Distributing the stress is intended to prevent the plain portion 43 from tearing.

[0132] Width d of the core side plain area B1 B1 is designed so that the cavity in the core of the electrode assembly is not blocked when the pattern of the middle plain portion B2 is bent toward the core.

[0133] In one embodiment of the present invention, at least a portion of the uncoated portion of the pattern 1 to pattern 7 of the electrode plate according to the third embodiment is divided into a plurality of segments by incision grooves of a predetermined depth (not shown).

[0134] In one example, the width d of the core-side uncoated portion B1 B1 may increase in proportion to the length from the reference line to the first side of pattern 1 or the height of the segment of pattern 1.

[0135] In a specific example, when the electrode plate 50 is used to manufacture an electrode assembly for a cylindrical cell having a form factor of 46800, the width d of the core-side uncoated portion B1 is B1 can be set to 180 mm to 350 mm depending on the diameter of the core of the electrode assembly.

[0136] In one example, the width of each pattern can be designed to form the same winding turn of the electrode assembly.

[0137] In another example, the height of the middle uncoated portion B2 may have a step shape that increases and then decreases from the core side toward the outer periphery.

[0138] In yet another example, the outer circumferential uncoated portion B3 may be modified to have the same structure as that of the second embodiment.

[0139] In yet another example, the pattern structure applied to the middle solid portion B2 may extend to the outer solid portion B3 (see dotted lines).

[0140] 7a is a plan view showing the structure of an electrode plate 60 according to a fourth embodiment of the present invention, in which divided pieces are formed over the entire length of the middle uncoated portion.

[0141] 7a, in the fourth embodiment of the electrode plate 60, the heights of the core-side uncoated portion B1 and the outer-side uncoated portion B3 are relatively lower than the middle uncoated portion B2. The heights of the core-side uncoated portion B1 and the outer-side uncoated portion B3 may be the same or different.

[0142] Preferably, at least a portion of the intermediate uncoated portion B2 may include a plurality of minute segments 61. The height of the plurality of minute segments 61 may increase stepwise from the core side toward the outer periphery side.

[0143] In one embodiment of the present invention, the entire or at least a portion of the divided segment is bent in the radial direction (toward the winding center) of the electrode assembly or in the opposite radial direction. The bending of the divided segment may be performed at a position spaced a predetermined height above the notch valley (bottom of the cut groove). In one embodiment of the present invention, the point where the inclination of a tangent to the portion of the divided segment that is actually bent toward the center by an external force begins to become 45° or less is referred to as the bending point. The inclination of a tangent refers to the angle between a tangent to the bending point and a plane perpendicular to the winding axis of the electrode assembly. Meanwhile, a line that includes the bending point and is horizontal to the reference line is referred to as the bending line.

[0144] Meanwhile, in an embodiment of the present invention, the heights of the plurality of incision grooves corresponding to the notch valleys may be the same or different from each other.

[0145] When the heights are the same, an imaginary straight line extending in the winding direction X from the height corresponding to the notch valley is used as the reference line.

[0146] If most of the notch valleys of the incision grooves are located at a specific height and only the height of some of the notch valleys is different from the specific height, the reference line may be determined at a height corresponding to the specific height. For example, if 50% or more of the notch valleys are located at a specific height, the reference line may be determined at a height corresponding to the height of these notch valleys. Alternatively, the reference line may be determined based on the height of the notch valley of the incision groove that occupies the longest length in the winding direction. For example, if about two-thirds of the total length occupied by the notch valleys of the incision grooves in the winding direction has a first height and the height of the notch valleys of the remaining one-third is different from the first height, the reference line may be determined at a position corresponding to the first height.

[0147] If the heights of the notch valleys of the incision grooves are not concentrated at a particular height (i.e., if the most concentrated incision grooves are less than 50%), the reference line may be determined as the average height of the notch valleys of the incision grooves. For example, if the length of the incision grooves with a notch valley height x in the winding direction is 30%, the length of the incision grooves with a notch valley height y in the winding direction is 30%, and the length of the incision grooves with a notch valley height z in the winding direction is 40%, the reference line may be located at "x*0.3+y*0.3+z*0.4". The height of the notch valley may be a relative distance at a specific point based on an arbitrary perpendicular line to the winding axis direction. For example, the height of the incision groove may be based on the distance from the second side to the incision groove.

[0148] Meanwhile, in one embodiment of the present invention, the bending point may be located approximately 2 mm to 3 mm above the notch valley and may be disposed parallel to the reference line.

[0149] Meanwhile, in one embodiment of the present invention, the reference line may be the same as or different from a line obtained by extending a point of the non-coating portion having the minimum height in the winding direction X. In a specific embodiment, the reference line may be the same as a line obtained by extending a point of the non-coating portion having the minimum height in the winding direction.

[0150] The segment 61 may be laser notched or may be formed by known metal foil cutting processes such as ultrasonic cutting or punching.

[0151] In the fourth embodiment, to prevent damage to the active material portions 42 and / or the insulating coating layer 44 during the bending process of the uncoated portion 43, a gap of a predetermined distance is preferably provided between the notched valleys between the divided pieces 61 and the active material portions 42. This is because stress is concentrated near the lower ends of the cutting lines when the uncoated portion 43 is bent. The gap is preferably 0.2 mm to 4 mm. Adjusting the gap within this range can prevent damage to the active material portions 42 and / or the insulating coating layer 44 near the lower ends of the cutting lines due to stress generated during the bending process of the uncoated portion 43. In addition, the gap can prevent damage to the active material portions 42 and / or the insulating coating layer 44 due to tolerances during notching or cutting of the divided pieces 61. Preferably, when the electrode plate 40 is wound into an electrode assembly, at least a portion of the insulating coating layer 44 may be exposed to the outside of the separator. In this case, when the segment 61 is bent, the insulating coating layer 44 can support the notched valley.

[0152] The gap between the notched valley of the segment and the active material layer may be preferably 1.0 mm, which may be more effective when the electrode is a negative electrode.

[0153] The gap between the notched valley of the segment and the active material layer may be more preferably 2.0 mm or more, which is particularly effective when the electrode is a positive electrode.

[0154] A gap smaller than the above range may not provide the sufficient damage prevention effect described above, and a cap larger than the above range may result in no further increase in damage prevention effect and only a decrease in the capacitance of the electrode.

[0155] The boundary between the uncoated region where the active material layer is not coated and the region where the active material layer is coated may be covered with an insulating layer, and in this case, a predetermined gap may also be provided between the notched valley of the divided piece and the insulating layer.

[0156] Such a gap may be between 0.2 mm and 1.5 mm.

[0157] A gap smaller than the above range may not be able to fully exert the above-mentioned damage prevention effect, and a cap larger than the above range may result in no further increase in the damage prevention effect and may result in a reduction in the bending support effect of the insulating coating layer.

[0158] The plurality of segment pieces 61 may be arranged in a plurality of segment groups from the core side toward the outer periphery side. The width, height, and spacing pitch of the segment pieces belonging to the same segment group may be substantially the same.

[0159] Meanwhile, in one embodiment of the present invention, the width of the electrode active material portion of the positive electrode plate in the electrode assembly may be equal to or narrower than the width of the electrode active material portion of the negative electrode plate, and the width of the electrode active material portion of the positive electrode plate may be disposed within the width of the electrode active material portion of the negative electrode plate in the width direction.

[0160] FIG. 41 is a schematic diagram of a portion of a cross section of a wound electrode assembly. Referring to this, a positive electrode plate 11 and a negative electrode plate 10 are stacked with a separator SP interposed therebetween. Here, reference numeral 11cc denotes a positive electrode current collector, reference numeral 10cc denotes a negative electrode current collector, and reference numerals 11ea and 10ea denote the electrode active material portion of the positive electrode plate and the electrode active material portion of the negative electrode plate, respectively. The width of the electrode active material portion of the positive electrode plate is narrower than that of the negative electrode plate and is disposed within the width of the electrode active material portion of the negative electrode plate. Meanwhile, the ends of the positive electrode current collector 11cc and the negative electrode current collector 10cc include the split pieces as described above and are folded as shown in FIG. 42. The open space created by the narrower width of the electrode active material portion of the positive electrode plate than that of the negative electrode plate provides a path for the electrolyte to move within the jelly roll-type electrode assembly, which is advantageous for electrolyte impregnation.

[0161] Meanwhile, each electrode active material portion may include a sliding portion at at least one end in the width direction, the sliding portion having a thickness reduced compared to the central region. Referring to Figure 42, which shows a specific embodiment of the present invention, the sliding portion may be formed at one end of both ends that contacts the uncoated portion. The sliding portion may be formed on both the positive electrode and the negative electrode, or on one of them. When a sliding portion is formed at each end of the positive electrode and the negative electrode, the sliding portions may be arranged in opposite directions.

[0162] In a specific embodiment of the present invention, the sliding portion may be covered with an insulating layer. As described above, when an insulating layer is formed on the non-coating portion, the insulating layer may be formed to extend to the sliding portion.

[0163] The sliding portion may 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 applied to the electrode current collector. The sliding phenomenon refers to a phenomenon in which a smaller amount of electrode active material is applied at the boundary region of the slurry application than at the other regions due to the spreading of the slurry containing the electrode active material, resulting in the slurry at the boundary region having a generally inclined shape. This sliding phenomenon may form a sliding portion at the end of the electrode active material portion that is generally inclined downward in the direction from the coated portion to the uncoated portion. The insulating layer is not particularly limited as long as it contains an insulating material, and any insulating polymeric material or inorganic material may be used without limitation.

[0164] 7a and 9a, the electrode plate 60 of the fourth embodiment may be provided with a separator SP facing the active material portion 42 and / or the insulating coating layer 44 to form an electrode assembly.

[0165] 7b, 7c, 8, 9b and 9c, the position where the end of the separator is located on the uncoated portion of the electrode plate in the electrode assembly according to the embodiment of the present invention will be described in more detail.

[0166] In one embodiment of the present invention, the uncoated portion may include a plurality of segments, and the depths of the notch valleys between the segments may be the same. In this case, a line connecting points corresponding to the depths of the notch valleys is defined as a reference line.

[0167] In this case, the reference line may correspond to a line obtained by extending the minimum height of the core-side uncoated portion, the outer periphery-side uncoated portion, and the intermediate uncoated portion to both ends of the uncoated portion.

[0168] The more one end of the separator in the width direction protrudes outside the jelly roll, i.e., toward the outside of the electrode assembly, the more negatively it affects the welding characteristics. On the other hand, the more one end of the separator in the width direction is located inside the jelly roll, i.e., toward the inside of the electrode assembly, the greater the risk of short-circuiting between the positive and negative electrodes, which is problematic.

[0169] Therefore, in the present invention, one end SL of the separator in the width direction is located either toward the outside or the inside of the electrode assembly within a predetermined distance from the reference line, where the outside of the electrode assembly refers to the direction from the active material layer of the electrode plate toward the uncoated portion, i.e., the direction toward the first side, and the inside refers to the opposite direction, i.e., the direction toward the second side.

[0170] In a specific embodiment, when the segment having the smallest height among the plurality of bent segments is defined as the smallest bent segment, one end of the separator in the width direction may be positioned toward the outside (first side) of the electrode assembly at less than 50%, within 40%, within 30%, within 20%, or within 10% of the height Ha of the smallest bent segment relative to the reference line. Preferably, it may be positioned toward the outside of the electrode assembly at within 30%. In this case, the separator may be positioned so that the notch valleys of the incision grooves between the segment segments are covered and not exposed. If the separator is positioned closer to the first end of the segment segments than the above range, the separator may be damaged by heat during subsequent welding of the segment segments.

[0171] According to another embodiment, one end of the separator in the width direction may be located inward (toward the second side) of the electrode assembly within 30%, 20%, or 10% of the height Ha of the minimum bend segment relative to the reference line. When located below the reference line in this manner, all or at least a portion of the notch valley (or the like) may be exposed without being covered by the separator. When the separator is located inward beyond the above range, it is difficult to ensure insulation between the positive and negative electrodes.

[0172] Furthermore, according to one embodiment of the present invention, controlling one widthwise end of the separator to be positioned close to the reference line allows the electrolyte to flow into the electrode assembly along the notched valley (open space), which is advantageous for impregnation. In other words, when the segments are folded and the folded segments are stacked, the electrolyte may be hindered from moving into the electrode assembly. However, when the end of the separator is positioned close to the notched valley, as in the present invention, the electrolyte is not hindered from flowing into the electrode assembly. Specifically, when the electrolyte is injected into the electrode assembly, the electrolyte moves into the notched groove between the segments. At this time, the electrolyte impregnates the notched valley, i.e., the end of the separator positioned close to the reference line, and ultimately penetrates into the active material layer of the electrode. As a result, the electrolyte impregnation uniformity within the electrode assembly is improved.

[0173] Meanwhile, in yet another embodiment of the present invention, one end SL of the separator may be located between the folding point and the boundary line between the first and second portions. That is, one end of the separator may be located between the folding point and a reference line or below the reference line. More specifically, if the shortest distance between the reference line and the maximum height (highest point) of the surface region of the electrode assembly in the winding axis direction is defined as the height HS of the surface region, one end of the separator in the width direction may be located toward the outside or the inside of the electrode assembly within 90% of the height HS of the surface region from the reference line. The surface region refers to a region formed at the upper or lower end of the winding axis direction by continuous overlapping of adjacent winding turn segments in the radial or opposite direction in the electrode assembly.

[0174] In one embodiment of the present invention, the electrode assembly may include a surface region formed by bending the plurality of segments in a radial direction of the electrode assembly. In other words, the surface region is a region formed at an upper end or a lower end of the winding axis direction of the electrode assembly by continuously overlapping segments of adjacent winding turns among the folded segments in a radial direction or an opposite direction.

[0175] In another embodiment of the present invention, the surface region may include one or more uniform stack number sections in which the number of stacks of the divided segments is maintained constant along the radial direction, and one or more decreasing stack number sections located adjacent to the uniform stack number sections in which the number of stacks of the divided segments decreases as the distance from the uniform stack number section increases.

[0176] That is, the plurality of segments are folded radially of the electrode assembly and stacked in multiple layers to form a surface region, and the surface region may include a uniform stacking number section in which the number of stacked segments is the same along the radial direction, and a decreasing stacking number section adjacent to the uniform stacking number section, in which the number of stacked segments decreases with increasing distance from the uniform stacking number section. In one embodiment of the present invention, the stack thickness of the segments in the uniform stacking number section may be 50 μm to 875 μm.

[0177] In one embodiment, the radial lengths of the uniform lamination number section and the reduced lamination number section relative to the center of the core of the electrode assembly may correspond to the radial length of a radial section in which a winding turn including the plurality of split segments is located.

[0178] In another embodiment, the radius at which the uniform lamination number section starts, based on the center of the core of the electrode assembly, may correspond to the radius at which the intermediate uncoated portion starts.

[0179] Preferably, the number of stacked pieces in the uniform stacking section may be 10 to 35.

[0180] In still another embodiment, the ratio of the radial length of the uniform lamination number section to the radial lengths of the uniform lamination number section and the decreasing lamination number section may be 30% to 85%.

[0181] Here, the number of segments that intersect with a virtual line parallel to the winding axis direction at any radial position in the surface region is defined as the number of stacked segments at that radial position.

[0182] Figure 43 is a schematic diagram showing a cross section of a folded surface region F formed by bending a divided piece 61 toward the core C of the electrode assembly 80. In Figure 43, the cross section of the folded surface region F is shown only on the left side with respect to the winding axis of the electrode assembly 80. The folded surface region F may be formed on both the top and bottom of the electrode assembly 80. Figure 44 is a perspective view schematically showing an electrode assembly 80 on which a folded surface region F is formed.

[0183] 43 and 44, the folded surface region F has a structure in which the division segments 61 are stacked in multiple layers in the winding axis direction. The stacking direction is the winding axis direction (Y axis). Section 1 is a core-side uncoated portion without division segments, and sections 2 and 3 are sections where winding turns including the division segments 61 are located and may be intermediate uncoated portions. Here, the height of the division segments 61 in Section 2 may increase toward the outer periphery, while in Section 3, the division segment height may be uniform up to the outer periphery of the electrode assembly. Here, the radial lengths of Sections 2 and 3 may vary. Meanwhile, the uncoated portion (outer periphery uncoated portion B3) included in at least one winding turn, including the outermost winding turn, may not include a division segment structure. In this case, the uncoated portion (outer periphery uncoated portion B3) may be excluded from Section 3.

[0184] Meanwhile, the number of stacked segments 61 may vary depending on the radial position at any radial position in Section 2 and Section 3. Preferably, the number of stacked segments 61 at each position of the folded surface region F can be adjusted as desired by adjusting the height, width, and spacing pitch of the segment segments 61 according to the radius of the winding turn containing the segment segments 61.

[0185] In one embodiment of the present invention, the separator edge is located between the bottom surface of the stacked region and the notch valley in the uniform stacking region. The electrolyte moves through minute gaps between the stacked segments due to capillary action. Since the separator edge is located close to the bottom surface of the stacked region in the uniform stacking region, the electrolyte quickly contacts the separator edge during electrolyte injection, improving electrolyte penetration into the electrode assembly.

[0186] Furthermore, a uniform stacking number section, particularly a uniform stacking number section in which the number of stacked segments is 10 or more, can be set as a preferred welding target area. The welding target area is a section in which at least a portion of the current collector can be welded. When a predetermined number of stacked segments is ensured in this uniform stacking number section, damage to the separator due to welding can be prevented.

[0187] 7b, 7c, 9b, or 9c, the separator segments of group 1 may be the smallest bent segments, and one widthwise end of the separator may be positioned toward the outside of the electrode assembly (toward the first side of the body) within 30% or less of the height Ha of the smallest bent segment from the reference line, or one widthwise end of the separator may be positioned toward the inside of the electrode assembly (toward the second side) within 30% of the height Ha of the smallest bent segment from the reference line. More specifically, the separator segments of group 1 may be the smallest bent segments, and one widthwise end of the separator may be positioned toward the outside of the electrode assembly (toward the first side) within 30% of the height Ha of the smallest bent segment from the reference line. Referring to FIG. 7b or 9b, if one end of the separator is positioned above the reference line, one end of the separator is positioned between Hb. Here, the maximum length of Hb is less than 50% of the height (length) of the minimum bending segment. On the other hand, when one end of the separation membrane is located below the DL, the maximum length of Hb is 30% of the height of the minimum bending segment.

[0188] That is, in one embodiment of the present invention, the base segment for arranging the separation membrane refers to the segment with the smallest height among the bent segments, and is referred to as the minimum bent segment.

[0189] In a specific embodiment of the present invention, the minimum bending segment may be 2 mm or more, and the height of the minimum bending segment is greater than the height of the bending point. If the height of the segment is less than 2 mm, the segment may not be smoothly folded due to interference between the separator and the segment. Therefore, the minimum bending segment may be determined from a segment having a height of 2 mm or more.

[0190] According to one embodiment of the present invention, in the minimum bending segment, a height A from a reference line to the bending line based on the bending line may be equal to or longer than a length from the bending line to a height B of the bending segment. Alternatively, in the minimum bending segment, a height A from a reference line to the bending line based on the bending line may be equal to or shorter than a length from the bending line to a height B of the bending segment.

[0191] In one embodiment of the present invention, the electrode assembly may further include a segment (segment A) having a height lower than the minimum bent segment. In this case, segment A is not bent. In a specific embodiment, segment A may be disposed closer to the core than other segments among the plurality of segments.

[0192] In an embodiment of the present invention, the electrode assembly may not include a segment having a height lower than the minimum bent segment, and the minimum bent segment may be the minimum segment.

[0193] For example, if the height of the minimum bent piece is 5 mm, one end of the separator in the width direction may be located toward the outside of the electrode assembly within 1.5 mm or less from the reference line, or one end of the separator in the width direction may be located toward the inside of the electrode assembly within 1.5 mm from the reference line.

[0194] In another example, when the height of the smallest bent piece is 6 mm, one end of the separator in the width direction may be positioned toward the outside of the electrode assembly within 1.8 mm or less from the reference line, or one end of the separator in the width direction may be positioned toward the inside of the electrode assembly within 1.8 mm from the reference line.

[0195] FIG. 8 is a diagram showing the definition of the width, height and spacing between the segments 61, that is, the separation pitch, according to an embodiment of the present invention.

[0196] 8, the width C1, height C2, and spacing pitch C3 of the divided pieces 61 are designed to prevent tearing of the plain portion 43 during bending and to improve welding strength by sufficiently increasing the number of overlapping layers of the plain portion 43 while preventing abnormal deformation of the plain portion 43. Abnormal deformation refers to the portion (C4) corresponding to the reference line DL being unable to maintain a straight state and being distorted irregularly.

[0197] According to one embodiment of the present invention, the width C1 of the segment 61 can be adjusted preferably within a range of 1 mm to 6 mm. If C1 is less than 1 mm, when the segment 61 is bent toward the core, the overlap may not be sufficient to ensure sufficient welding strength, or an open space (gap) may be generated. On the other hand, if C1 exceeds 6 mm, the uncoated portion 43 near the reference line DL may be torn by stress when the segment 61 is bent, depending on the curvature of the wound electrode. In addition, the height C2 of the segment 61 can be adjusted within a range of 2 mm to 10 mm. If the height C2 of the segment 61 is less than 2 mm, the segment 61 may not be bent smoothly, or when the segment 61 is bent toward the core, the overlap may not be sufficient to ensure sufficient welding strength, or an open space (gap) may be generated. On the other hand, if C2 exceeds 10 mm, it is difficult to manufacture an electrode plate while maintaining uniform flatness of the uncoated portion in the winding direction X. That is, the uncoated portion becomes higher and swells.

[0198] Furthermore, the separation pitch C3 of the segment pieces 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, stress may cause the uncoated portion 43 near the reference line DL (near the bottom of the groove between two adjacent segment pieces) to break when the segment pieces 61 are bent. On the other hand, if the separation pitch C3 exceeds 1 mm, the segment pieces 61 may not overlap enough to ensure sufficient welding strength when bent, or empty spaces (gaps) may be generated.

[0199] In one embodiment of the present invention, the corners of the two divided pieces may be connected in a straight line, i.e., the bottom portion of the cut groove may be a flat straight line extending in the winding direction X. A rounded reinforcement portion may be added to the corners.

[0200] The radius r of the round reinforcement portion may be 0.02 mm or more. If the radius is greater than this, the stress dispersion effect can be reliably achieved. The radius of the round reinforcement portion may be 0.1 mm or less. If the radius is greater than 0.1 mm, the stress dispersion effect will not be further increased, and the space near the bottom of the cut groove may be reduced, which may hinder the impregnation of the electrolyte.

[0201] Referring further to FIG. 7a, the width d of the core-side uncoated portion B1 B1 is designed so that when the divided piece 61 of the middle plain portion B2 is bent toward the core, the cavity of the core of the electrode assembly is not blocked.

[0202] In one example, the width d of the core-side uncoated portion B1 B1 may increase in proportion to the height C2 of the segment 61 of group 1.

[0203] 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 width d of the core-side uncoated portion B1 is B1 can be set to 180 mm to 350 mm depending on the diameter of the core of the electrode assembly.

[0204] In one example, the width of each segment group can be designed to form the same winding turn of the electrode assembly.

[0205] In another example, the width and / or height and / or spacing pitch of the minute segments 61 belonging to the same minute segment group may increase or decrease gradually and / or stepwise and / or irregularly within the group.

[0206] Groups 1 to 7 are merely examples of segment groups. The number of groups and the number of segment pieces 61 included in each group can be adjusted so that the segment pieces 61 are overlapped in multiple layers to maximize stress distribution during the bending process of the plain portion 43 and ensure sufficient welding strength.

[0207] In yet another example, the height of the outer plain portion B3 may decrease gradually or in steps, as in the first and second embodiments. The divided structure of the intermediate plain portion B2 may extend to the outer plain portion B3 (see dotted lines). In this case, the outer plain portion B3 may also include multiple divided segments, similar to the intermediate plain portion B2. In this case, the divided segments of the outer plain portion B3 may have a greater width, height, and / or spacing pitch than the intermediate plain portion B2.

[0208] 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 may be formed in eight groups. In this case, the segments of groups 1 to 7 may be formed in the middle uncoated portion B2, and the segment of group 8 may be formed in the outer uncoated portion B3 as in the example described above.

[0209] In a specific example, the width d of the core-side uncoated portion B1 B1The width of Group 1 may be 35% to 40% of the width of core-side plain portion B1. The width of Group 2 may be 130% to 150% of the width of Group 1. The width of Group 3 may be 120% to 135% of the width of Group 2. The width of Group 4 may be 85% to 90% of the width of Group 3. The width of Group 5 may be 120% to 130% of the width of Group 4. The width of Group 6 may be 100% to 120% of the width of Group 5. The width of Group 7 may be 90% to 120% of the width of Group 6. The width of Group 8 may be 115% to 130% of the width of Group 7.

[0210] The reason why the widths of groups 1 to 8 do not show a consistent increase or decrease pattern is that although the width of the segments gradually increases from group 1 to group 8, the number of segments included in a group is limited to an integer. Therefore, the number of segments may decrease in a particular segment group. Therefore, the width of the group may show an irregular change from the core side to the outer periphery side, as shown in the example above.

[0211] That is, when the winding direction widths of three adjacent segment groups in the radial direction of the electrode assembly are W1, W2, and W3, respectively, the electrode assembly may include a combination of segment groups in which W3 / W2 is smaller than W2 / W1.

[0212] In the specific example described above, this applies to groups 4 to 6. 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 smaller than 120% to 130%.

[0213] FIG. 9a is a plan view showing the structure of an electrode plate 70 according to a fifth embodiment of the present invention.

[0214] Referring to FIG. 9a, the electrode plate 70 of the fifth embodiment is substantially identical in configuration to the fourth embodiment (or modified form), except that the shape of the segment 61' is changed from a square to a trapezoid, compared to the fourth embodiment.

[0215] FIG. 10 is a diagram showing the definitions of the width, height and separation pitch of the trapezoidal segment 61'.

[0216] Referring to FIG. 10, the width D1, height D2, and spacing pitch D3 of the divided pieces 61' are designed to prevent tearing of the uncoated portion D4 near the reference line DL during bending of the uncoated portion 43 and to ensure sufficient welding strength by sufficiently increasing the number of overlapping layers of the uncoated portion 43 while preventing abnormal deformation of the uncoated portion 43.

[0217] 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, when the segment 61' is bent toward the core, the segment 61' will not overlap to an extent sufficient to ensure sufficient welding strength, or an empty space (gap) will be generated. On the other hand, if D1 exceeds 6 mm, the curvature of the wound electrode may cause stress to tear the uncoated portion D4 near the reference line DL when the segment 61' is bent. Furthermore, 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' will not be bent smoothly, or when the segment 61' is bent toward the core, the segment 61' will not overlap to an extent sufficient to ensure sufficient welding strength, or an empty space (gap) will be generated. On the other hand, if D2 exceeds 10 mm, it is difficult to manufacture an electrode plate while maintaining uniform flatness of the uncoated portion 43 in the winding direction. Furthermore, the spacing pitch D3 of the divided segments 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, stress may cause the uncoated portion D4 near the reference line DL to break when the divided segments 61' are bent. On the other hand, if D3 exceeds 1 mm, the divided segments 61' may not overlap enough to ensure sufficient welding strength when bent, or empty spaces (gaps) may be generated.

[0218] When the segments are trapezoidal, the separation pitch D3 may be defined as the distance between the corners of two adjacent segments 61'. The corners of the two adjacent segments may be connected in a straight line. That is, the bottom of the cut groove may be a flat, straight line extending in the winding direction X.

[0219] The corners may further be provided with rounded reinforcement portions, thereby eliminating stress concentration that may occur at the corners.

[0220] The radius r of the round reinforcing portion may be 0.02 mm or more, which can reliably provide the effect of stress dispersion.

[0221] The radius of the round reinforcing portion may be 0.1 mm or less. If the radius exceeds 0.1 mm, the effect of stress dispersion will not be further increased, and the space near the bottom of the cut groove will be reduced, which may hinder the impregnation of the electrolyte.

[0222] The spacing pitches C3 and D3 may be determined in relation to the widths C1 and D1 of the adjacent segments 61 and 61' defined therein, measured in the winding direction. For example, it is preferable that the spacing pitch between the segments increases as the width of the segments increases in the winding direction. This allows for uniform distribution of electrolyte impregnation along the winding direction of the electrode assembly.

[0223] The width of the segment in the winding direction may be set to gradually increase from the core side toward the outer periphery of the electrode assembly. The width of the segment in the winding direction may increase gradually or stepwise from the core side toward the outer periphery of the electrode assembly. For example, the widths C1 and D1 of the segment in the winding direction may be within a range of 1 mm to 6 mm, decreasing toward the core side and increasing toward the outer periphery.

[0224] Accordingly, the spacing pitches C3 and D3 may also be within a range of 0.5 mm to 1 mm, and may increase gradually or stepwise from the core side to the outer periphery side of the electrode assembly.

[0225] In the fifth embodiment, the lower interior angle θ of the trapezoid of the plurality of segment pieces 61′ may increase from the core side toward the outer periphery. As the radius of the electrode assembly increases, the radius of curvature also increases. If the lower interior angle θ of the segment pieces 61′ increases with the radius of the electrode assembly, stresses occurring in the radial and circumferential directions when the segment pieces 61′ are bent can be alleviated. Furthermore, as the lower interior angle θ increases, the overlapping area and number of overlapping layers with the inner segment pieces 61′ when the segment pieces 61′ are bent also increase, thereby ensuring uniform welding strength in the radial and circumferential directions and enabling the bent surfaces to be formed flat.

[0226] In one example, when electrode plate 70 is used to manufacture an electrode assembly for a cylindrical cell with a form factor of 46800, the interior angle of segment 61' may increase stepwise in the range of 60° to 85° as the radius of the electrode assembly increases from 4 mm to 22 mm.

[0227] In another example, the height of the outer plain portion B3 may decrease gradually or in steps, as in the first and second embodiments. The divided structure of the intermediate plain portion B2 may extend to the outer plain portion B3 (see dotted lines). In this case, the outer plain portion B3 may also include multiple divided segments, similar to the intermediate plain portion B2. In this case, the divided segments of the outer plain portion B3 may have a greater width, height, and / or spacing pitch than the intermediate plain portion B2.

[0228] When the middle plain portion B2 includes a plurality of segments 60, 60' as in the fourth and fifth embodiments, the shape of each segment 60, 60' can be changed to a triangle, semicircle, semi-ellipse, parallelogram, or the like.

[0229] The shapes of the segments 60, 60' may also be varied for each region of the intermediate plain portion B2. For example, a round shape (e.g., semicircular, semi-elliptical, etc.) that is advantageous for stress dispersion may be applied to the section where stress is concentrated, and a polygonal shape (e.g., quadrilateral, trapezoid, parallelogram, etc.) with the largest possible area may be applied to the section where stress is relatively low.

[0230] In the fourth and fifth embodiments, the division structure of the middle uncoated portion B2 can also be applied to the core-side uncoated portion B1. However, if a division structure is applied to the core-side uncoated portion B1, there is a risk of reverse forming, in which the ends of the core-side uncoated portion B1 bend toward the outer periphery when the division segments 60, 60' of the middle uncoated portion B2 are bent due to the radius of curvature of the core. Therefore, it is preferable not to apply a division structure to the core-side uncoated portion B1, or even if a division structure is applied, to adjust the width, height, and / or spacing of the division segments 60, 60' to a level that does not cause reverse forming, taking into account the radius of curvature of the core.

[0231] The height of the segment where such reverse forming can occur may be less than about 3 mm. In addition, if the height of the segment is less than 2 mm, the segment and the separator interfere with each other, making it difficult to bend. In addition, if the height of the segment is less than 4 mm, the welding process of the segment does not proceed smoothly. Therefore, the minimum height (H min ) may be 2 mm or more, 3 mm or more, 4 mm or more, or 5 mm or more. Thus, the height of the minimum bending segment may be 2 mm or more, 3 mm or more, 4 mm or more, or 5 mm or more.

[0232] Therefore, the minimum height (H min If one end SL of the separation membrane in the width direction is within a range of ±30% (based on the reference line) of the height Ha of the smallest bendable segment among segments having a height of at least 2 mm, 3 mm, 4 mm, or 5 mm (for example, as described above), impregnation can be significantly improved. In other words, when determining the smallest segment that defines the position of one end SL of the separation membrane in the width direction, segments that may cause reverse forming or segments that cannot be bent can be excluded.

[0233] From another perspective, the height Ha of the minimum bending segment in the plain area and the minimum height (H min ) the largest value {max(Ha,H minIf one end SL in the width direction of the separation membrane is within a range of ±30% of the above { )}, the impregnation property can be significantly improved.

[0234] From another perspective, the minimum height (H min If the widthwise end SL of the separator is within a range of ±30% of the reference line DL, the impregnation of the electrolyte can be significantly improved. This range can be the reference line DL ±1.5 mm, the reference line DL ±1.2 mm, the reference line DL ±0.9 mm, or the reference line DL ±0.6 mm.

[0235] Alternatively, the position of one end of the separation membrane in the width direction may be within the range of DL±0.3Ha and DL±1.5mm, within the range of DL±0.3Ha and DL±1.2mm, within the range of DL±0.3Ha and DL±0.9mm, or within the range of DL±0.3Ha and DL±0.6mm.

[0236] The electrode plate structure of the above-described embodiment (variant) may be applied to at least one of a first electrode plate and a second electrode plate having different polarities included in a jelly roll-type electrode assembly. Furthermore, when the electrode plate structure of the embodiment (variant) is applied to one of the first electrode plate and the second electrode plate, a conventional electrode plate structure may be applied to the other. Furthermore, the electrode plate structures applied to the first electrode plate and the second electrode plate may not be the same, but may be different.

[0237] As an example, when the first electrode plate and the second electrode plate are a positive electrode plate and a negative electrode plate, respectively, any one of the embodiments (variants) may be applied to the first electrode plate, and a conventional electrode plate structure (see FIG. 1) may be applied to the second electrode plate.

[0238] As another example, when the first electrode plate and the second electrode plate are a positive electrode plate and a negative electrode plate, respectively, any one of the embodiments (variants) may be selectively applied to the first electrode plate, and any one of the embodiments (variants) may be selectively applied to the second electrode plate.

[0239] In one embodiment of the present invention, 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.

[0240] The positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; 1+x Mn 2-x Lithium manganese oxides such as O4 (x=0~0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O5, LiV3O4, V2O5, and Cu2V2O7; chemical formula LiNi 1-x M x Lithium nickel oxide with nickel site structure represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, x = 0.01 to 0.3); chemical formula: LiMn 2-x M x Examples of the oxides include, but are not limited to, lithium manganese composite oxides represented by Li2Mn3MO8 (M=Fe, Co, Ni, Fe, Cr, Zn, or Ta, x=0.01 to 0.1) or Li2Mn3MO8 (M=Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which part of the lithium in the chemical formula is substituted with an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, or composite oxides formed by a combination of these, which have a lithium intercalation material as the main component.

[0241] The positive electrode current collector has a thickness of, for example, 3 μm to 500 μm. Such a positive electrode current collector is not particularly limited as long as it does not induce chemical changes in the battery and is conductive. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. may be used. The electrode current collector may have fine irregularities on its surface to increase the adhesive strength of the positive electrode active material, and may be used in various forms such as a film, sheet, foil, net, porous material, foam, or nonwoven fabric.

[0242] A conductive material may be further mixed with the positive electrode active material particles. The conductive material may be added, for example, in an amount of 1 to 50 wt % based on the total weight of the mixture containing the positive electrode active material. The conductive material may be any material that does not induce chemical changes in the battery and has high conductivity. Examples of such a conductive material include graphite such as natural graphite and artificial graphite; carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0243] The negative electrode is fabricated by coating and drying negative electrode active material particles on a negative electrode current collector, and may further include components such as the above-mentioned conductive material, binder, and solvent, as needed.

[0244] The negative electrode current collector has a thickness of, for example, 3 μm to 500 μm. Such a negative electrode current collector is not particularly limited as long as it has conductivity without inducing chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, those obtained by surface treatment with carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, etc. can be used. Also, similar to the positive electrode current collector, fine irregularities may be formed on the surface to strengthen the binding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven fabrics, etc.

[0245] The negative electrode active material is, for example, carbon such as graphitizable carbon and graphite-based carbon; Li x Fe2O3 (0 ≦ x ≦ 1), Li x WO2 (0 ≦ x ≦ 1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8) metal composite oxides; lithium metal; lithium alloys; silicon-based alloys; tin-based alloys; oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials, etc. can be used.

[0246] The binder polymer usable in the electrode is a component that aids in bonding between the electrode active material particles and the conductive material, etc., and to the electrode current collector, and is added, for example, in an amount of 1 to 50 wt % based on the total weight of the mixture containing the electrode active material. Examples of such binder polymers include, but are not limited to, any one binder polymer selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, 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 of these.

[0247] Non-limiting examples of solvents used in the preparation of the electrode include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or mixtures thereof, etc. Such solvents provide an appropriate level of viscosity so that a desired level of slurry coating layer is formed on the surface of the electrode current collector.

[0248] The negative electrode includes 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 includes a lower layer region that is in surface contact with the current collector, and an upper layer region that is in surface contact with the lower layer region and extends to a surface of the negative electrode active material layer. 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.

[0249] The lower layer region may contain natural graphite as the negative electrode active material, and the upper layer region may contain artificial graphite as the negative electrode active material.

[0250] The lower layer region and the upper layer region may each independently further include a silicon-based compound as a negative electrode active material.

[0251] The silicon-based compound may include one or more of SiOx (0≦x≦2) and SiC.

[0252] According to an embodiment of the present invention, the negative electrode may be manufactured by coating a lower layer slurry containing a lower layer negative electrode active material on a current collector and drying the slurry to form a lower layer region, and then coating an upper layer slurry containing an upper layer negative electrode active material on the lower layer region and drying the slurry to form an upper layer region.

[0253] Alternatively, according to an embodiment of the present invention, the negative electrode may include a step of preparing a lower layer slurry including a lower layer negative electrode active material and an upper layer slurry including an upper layer negative electrode active material; coating one surface of a negative electrode current collector with the lower layer slurry, and simultaneously or after a predetermined time interval, coating the upper layer slurry on the lower layer slurry; and drying the coated lower layer slurry and upper layer slurry simultaneously to form an active material layer.

[0254] In the latter method, a mixed region (intermixing) of different active materials may exist at the contact point between the lower and upper layers of the negative electrode. This is because, when an active material layer is formed by simultaneously or sequentially coating a lower layer slurry containing a lower layer negative electrode active material and an upper layer slurry containing an upper layer negative electrode active material onto a current collector and then drying them simultaneously, a predetermined mixed region is formed at the interface where the lower layer slurry and the upper layer slurry contact each other before drying, and then this mixed region is formed in the form of a layer during drying.

[0255] In the negative electrode active material layer according to an embodiment of the present invention, the weight ratio (or ratio of loading amount per unit area) of the upper layer region to the lower layer region may be 20:80 to 50:50, and more specifically, 25:75 to 50:50.

[0256] The thicknesses of the lower and upper regions of the negative electrode active material layer according to an embodiment of the present invention may not be exactly the same as the thicknesses of the coated lower layer slurry and the coated upper layer slurry, but the thickness ratio of the lower and upper regions of the negative electrode active material layer according to an embodiment of the present invention finally obtained after the drying or optional rolling process may be the same as the thickness ratio of the coated lower layer slurry and the coated upper layer slurry.

[0257] According to one embodiment of the present invention, a first slurry (slurry for the lower layer) is coated, and then a second slurry (slurry for the upper layer) is coated on the first slurry simultaneously or after a predetermined time lag. The predetermined time lag may be 0.6 seconds or less, 0.02 to 0.6 seconds, 0.02 to 0.06 seconds, or 0.02 to 0.03 seconds. Since the time lag between the coating of the first and second slurries is caused by the coating equipment, it is more preferable to coat the first and second slurries simultaneously. The second slurry may be coated on the first slurry using an apparatus such as a double slot die.

[0258] 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, rolling may be performed by a method commonly used in the art, such as a roll press, at a pressure of 1 to 20 MPa and a temperature of 15 to 30°C.

[0259] The step of simultaneously drying the coated lower layer slurry and upper layer slurry to form the active material layer may be performed by a method commonly used in the art using a device that combines a hot air dryer and an infrared dryer.

[0260] The weight % of the first binder polymer in the solid content of the lower layer slurry may be equal to or greater than the weight % of the second binder polymer in the solid content of the upper layer slurry. According to one embodiment of the present invention, the weight % of the first binder polymer in the solid content of the lower layer slurry may be 1.0 to 4.2 times, 1.5 to 3.6 times, or 1.5 to 3 times the weight % of the second binder polymer in the solid content of the upper layer slurry.

[0261] When the ratio of the weight percentage of the first binder in the coated lower layer slurry to the weight percentage of the second binder in the coated upper layer slurry satisfies this range, the binder in the lower layer region does not become too small, so detachment of the electrode layer does not occur, and the binder in the upper layer region does not become too large, so the resistance of the upper layer of the electrode decreases, which is advantageous for fast charging performance.

[0262] The weight percentage of the first binder polymer in the solid content of the lower layer slurry may be 2 to 30 weight percent, 5 to 20 weight percent, or 5 to 20 weight percent, and the weight percentage of the second binder polymer in the solid content of the upper layer slurry may be 0.5 to 20 weight percent, 1 to 15 weight percent, 1 to 10 weight percent, or 2 to 5 weight percent.

[0263] The total ratio (wt %) of the first binder polymer and the second binder polymer to the total solid content of the lower layer slurry and the upper layer slurry may be 2 to 20 wt %, or 5 to 15 wt %.

[0264] The separator includes a porous polymer substrate and a porous coating layer disposed on at least one surface or both surfaces of the porous polymer substrate, the porous coating layer including inorganic particles and a binder polymer.

[0265] The porous polymer substrate may be a polyolefin-based porous substrate.

[0266] The polyolefin-based porous substrate may be in the form of a porous film or non-woven web. The porous structure of the porous substrate facilitates the movement of electrolyte between the positive and negative electrodes, and increases the electrolyte impregnation of the substrate itself, ensuring excellent ionic conductivity. This prevents an increase in resistance within the electrochemical device, thereby preventing a decrease in the performance of the electrochemical device.

[0267] The polyolefin-based porous substrate used in the present invention can be any planar porous substrate that is commonly used in electrochemical elements, and the material and shape thereof can be selected from a variety of materials depending on the purpose.

[0268] The polyolefin-based porous substrate may be, but is not limited to, a film or nonwoven web formed from high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, or a mixture of two or more of these.

[0269] The polyolefin-based porous substrate may have a thickness of 5 μm to 30 μm, but this is merely an example, and thicknesses outside the above range may be adopted in consideration of mechanical properties and high-rate charge / discharge characteristics of the battery.

[0270] In one embodiment of the present invention, the porous substrate may be a porous film containing a polyolefin-based polymer resin. The porous film may be obtained by a conventional polymer film manufacturing method, such as melt-extrusion and stretching of a polymer material, or by forming pores using a pore-forming agent, but is not limited to these. In a specific embodiment, the porosity of the porous film may be 30 vol% to 60 vol%. Additionally or independently, the pores of the porous film 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 electrolyte and appropriate penetration strength can be ensured.

[0271] Meanwhile, the porous film may have a stretching ratio of 200% to 400%, more preferably 300% to 400%. If the stretching ratio is less than 200%, the probability of contact between electrodes increases when a nail penetrates the film, while if it is more than 400%, the surrounding area also stretches when a nail penetrates the film, thinning the separation membrane and reducing the barrier properties.

[0272] The nonwoven fabric sheet according to one embodiment of the present invention may be made of polyethylene (PE), polypropylene (PP), or a mixture thereof. For example, the nonwoven fabric sheet may be manufactured by fiber spinning. For example, the nonwoven fabric sheet may be manufactured by blending and spinning material fibers at or above their melting points using a melt blown method.

[0273] The nonwoven fabric sheet may have an elongation ratio of 200% to 400%, more preferably 300% to 400%. If the elongation ratio is less than 200%, the electrodes are more likely to come into contact with each other when a nail penetrates the sheet, whereas if the elongation ratio exceeds 400%, the peripheral portions of the sheet are also elongated when a nail penetrates the sheet, making the separation membrane thinner and reducing its barrier properties (blocking properties).

[0274] The nonwoven fabric sheet has a large number of pores with an average diameter of 0.1 to 10 μm. If the pore size is smaller than 0.1 μm, lithium ions and / or the electrolyte cannot move smoothly, and if the pore size is larger than 10 μm, the nonwoven fabric sheet may stretch when a nail penetrates, which may prevent contact between the positive electrode and the negative electrode, and this may not be an effect of the present invention.

[0275] The nonwoven fabric sheet may have a porosity of 40 to 70 vol%. If the porosity is less than 40 vol%, lithium ions and / or the electrolyte may not move smoothly, and if the porosity is greater than 70 vol%, the nonwoven fabric sheet may stretch when a nail penetrates it, preventing contact between the positive and negative electrodes, which is an effect of one embodiment of the present invention. The nonwoven fabric sheet thus manufactured may have an air permeability of 1 to 20 seconds / 100 mL.

[0276] The nonwoven fabric sheet may have a thickness of 10 μm to 20 μm, but this is merely an example and is not limited to this. A nonwoven fabric sheet having a thickness outside the above range may also be adopted depending on the permeability of the nonwoven fabric sheet.

[0277] The nonwoven fabric sheet can be bonded to the separator component below the nonwoven fabric sheet by lamination. Lamination can be performed at a temperature ranging from 100 to 150°C. However, if lamination is performed at a temperature lower than 100°C, the lamination effect will not be achieved, and if lamination is performed at a temperature higher than 150°C, there is a risk of partial melting of the nonwoven fabric.

[0278] The separator according to one embodiment of the present invention bonded by lamination under the above conditions has improved resistance to nail penetration compared to a separator made of a conventional nonwoven fabric sheet, and compared to a separator having a layer containing inorganic particles formed on at least one surface of a film or nonwoven fabric sheet.

[0279] In the porous coating layer, the inorganic particles are packed together and in contact with each other and bound by the binder polymer, thereby forming interstitial volumes between the inorganic particles, which may become empty spaces and form pores.

[0280] The inorganic particles used to form the porous coating layer are inorganic particles, i.e., particles that are within the operating voltage range (e.g., Li / Li + Inorganic particles that do not undergo oxidation and / or reduction reactions at a voltage (0 to 5 V relative to the reference voltage) may be further added. In particular, when inorganic particles with ion-transfer ability are used, the ionic conductivity in the electrochemical device can be increased, thereby improving performance. Furthermore, when inorganic particles with a high dielectric constant are used as the inorganic particles, they can contribute to increasing the degree of dissociation of electrolyte salts, such as lithium salts, in the liquid electrolyte, thereby improving the ionic conductivity of the electrolyte solution.

[0281] For the reasons mentioned above, the inorganic particles preferably include inorganic particles with a high dielectric constant having a dielectric constant of 5 or more, preferably 10 or more, inorganic particles having lithium ion conductivity, or a mixture thereof.

[0282] Non-limiting examples of inorganic particles having a dielectric constant of 5 or more include BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3 (PMN-PT), hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiC, aluminum hydroxides such as boehmite (γ-AlO(OH)), pseudoboehmite (Al2O3·H2O), diaspore (α-AlO(OH)), bayerite (α-AlO(OH)3), gibbsite (γ-AlO(OH)3), nordstrandite (AlO(OH)3), or mixtures thereof.

[0283] In particular, the above-mentioned BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), PB(Mg 1 / 3 Nb 2 / 3 Inorganic particles such as )O3-PbTiO3 (PMN-PT) and hafnia (HfO2) not only exhibit high dielectric constants of over 100, but also possess piezoelectricity, which generates a potential difference between the two surfaces when stretched or compressed under a certain pressure, preventing internal short circuits between the electrodes due to external impacts and improving the safety of electrochemical devices. Furthermore, when inorganic particles with high dielectric constants are used in combination with inorganic particles with lithium ion transport properties, the synergistic effects are multiplied.

[0284] Inorganic particles having lithium-ion conductivity refer to inorganic particles that contain lithium elements but do not store lithium and have the function of moving lithium ions. Inorganic particles having lithium-ion conductivity can transmit and move lithium ions due to a kind of defect existing inside the particle structure, so the lithium-ion conductivity in the battery can be improved, and thereby the battery performance can be enhanced. Non-limiting examples of the inorganic particles having lithium-ion conductivity include lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP) x O y -based glasses such as 14Li2O-9Al2O3-38TiO2-39P2O5 (0 < x < 4, 0 < y < 13), lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate such as Li 3.25 Ge 0.25 P 0.75 S4 (Li x Ge y P z S​​​​​​​​​​​​​​​​​​​​ In one embodiment of the present invention, the inorganic particles may include hydrophilic inorganic particles. Examples of hydrophilic inorganic particles include Al2O3 or aluminum hydroxide-based inorganic particles. Examples of the aluminum hydroxide-based inorganic particles include boehmite (γ-AlO(OH)), pseudoboehmite (Al2O3·H2O), diaspore (α-AlO(OH)), bayerite (α-AlO(OH)3), gibbsite (γ-AlO(OH)3), and nordstrandite (AlO(OH)3). In one embodiment of the present invention, the separator may include one or more of these hydrophilic inorganic particles. In particular, when a hydrophilic organic solvent, such as a carbonate-based organic solvent, is used as the organic solvent for the electrolyte, applying these hydrophilic inorganic particles to the porous coating layer of the separator can further improve the electrolyte impregnation of the electrode assembly. In one embodiment of the present invention, when a separator substrate made of a polyolefin-based material is used, it is difficult to ensure sufficient wettability with the electrolyte due to its hydrophobicity. In this case, applying hydrophilic inorganic particles to the porous coating layer formed on the surface can prevent the separator from having low wettability due to the hydrophobicity of the polyolefin-based separator substrate. The size of the inorganic particles in the porous coating layer is not limited, but is preferably 0.001 to 10 μm to form a coating layer of uniform thickness and achieve appropriate porosity. A particle size of less than 0.001 μm reduces the dispersibility of the inorganic particles. A particle size of more than 10 μm increases the thickness of the porous coating layer, resulting in reduced mechanical properties and excessively large pore size, potentially causing an internal short circuit during battery charging and discharging.

[0286] Meanwhile, the binder polymer forming the porous coating layer may be any one selected from the group consisting of polyvinylidene, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, 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, but is not limited thereto.

[0287] The composition ratio of inorganic particles to binder polymer used in the porous coating layer is preferably, for example, in the range of 50:50 to 99:1, and more preferably 70:30 to 95:5. If the content of inorganic particles relative to binder polymer is less than 50 parts by weight, the content of binder polymer will be too high, which may reduce the improvement in the thermal stability of the separator. Furthermore, the reduction in the void space formed between the inorganic particles may reduce the pore size and porosity, resulting in a deterioration in final battery performance. If the content of inorganic particles exceeds 99 parts by weight, the content of binder polymer will be too low, which may weaken the peel resistance of the porous coating layer.

[0288] The thickness of the porous coating layer is not particularly limited, but is preferably 0.01 μm to 20 μm. The pore size and porosity are also not particularly limited, but the pore size is preferably 0.001 μm to 10 μm, and the porosity is preferably 10 vol% to 90 vol%. The pore size and porosity depend mainly on the size of the inorganic particles. For example, when inorganic particles with a particle size of 1 μm or less are used, the formed pores will also be approximately 1 μm or less. This pore structure is filled with the electrolyte solution that is subsequently injected, and the filled electrolyte plays a role in ion transport. If the pore size and porosity are less than 0.001 μm and 10 vol%, respectively, the layer will function as a resistive layer, while if they exceed 10 μm and 90 vol%, respectively, the mechanical properties may be reduced.

[0289] The porous coating layer can be formed by dissolving or dispersing a binder polymer in a dispersion medium, adding inorganic particles to the dispersion medium to obtain a slurry for forming the porous coating layer, and then coating and drying the slurry on at least one surface of the substrate. The dispersion medium preferably has a solubility index similar to that of the binder polymer to be used and a low boiling point. This facilitates uniform mixing and subsequent removal of the dispersion medium. Non-limiting examples of suitable dispersion mediums include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, and mixtures thereof.

[0290] It is preferable to add inorganic particles to a dispersion in which the binder polymer is dispersed in a dispersion medium, and then crush the inorganic particles. In this case, the crushing time is preferably 1 to 20 hours, and the size of the crushed inorganic particles is preferably 0.001 to 10 μm, as described above. As a crushing method, a conventional method can be used, and a ball mill method is particularly preferable.

[0291] The binder polymer dispersion containing the dispersed inorganic particles is then coated onto at least one surface of a porous polymer substrate under a humidity condition of 10 to 80%, and then dried. The method for coating the dispersion onto the porous polymer substrate may be a conventional coating method well known in the art, such as dip coating, die coating, roll coating, comma coating, or a combination thereof.

[0292] In addition to the inorganic particles and binder polymer described above, the porous coating layer may further include other additives such as a conductive material.

[0293] The separator finally manufactured according to one embodiment of the present invention 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 separator may not function properly and its mechanical properties may deteriorate, while if it exceeds 100 μm, the battery characteristics may deteriorate during high-rate charge / discharge. The separator may also have a porosity of 40 vol% to 60 vol% and an air permeability of 150 to 300 sec / 100 mL.

[0294] According to an embodiment of the present invention, the porous polymer substrate may be made of polyethylene or polypropylene, and the inorganic particles in the porous coating layer may be made of Al oxide or Si oxide coating materials.

[0295] According to one embodiment of the present invention, the separator may include porous coating layers on both sides of a porous polymer substrate. In this case, a uniform solid electrolyte interfacial layer can be formed due to improved electrolyte impregnation performance, thereby ensuring superior air permeability compared to conventional single-sided inorganic-coated separators. For example, the air permeability may be within 120 s / 100 cc. Furthermore, even when inorganic porous coating layers are provided on both sides, the thickness can be the same as that of conventional single-sided inorganic-coated separators. For example, the thickness may be within 15.0 μm.

[0296] In another embodiment of the present invention, the separator may include a porous coating layer on either one of both surfaces of a porous polymer substrate, and in this case, the porous coating layer may be disposed so as to face the positive electrode. In this case, the volume of the electrode assembly may be minimized without damaging the insulating properties and mechanical properties of the separator, or the amount of electrode active material may be increased if the volume is the same, which is advantageous for improving energy density.

[0297] Furthermore, when a separator according to an embodiment of the present invention is used, the separator's stability is improved, ensuring heat resistance and compression resistance. Specifically, the separator can have heat resistance with a thermal shrinkage of 5% or less at 180°C, and can have a puncture strength of 550 gf or more. When core deformation occurs during cycling of a battery using such a separator, damage or puncture of the separator at the step can be prevented.

[0298] Hereinafter, the structure of an electrode assembly according to an embodiment of the present invention will be described in detail.

[0299] FIG. 11 is a cross-sectional view of a jelly-roll type electrode assembly 80 in which the electrode plate 40 of the first embodiment is applied to a first electrode plate (positive electrode plate) and a second electrode plate (negative electrode plate), taken along the Y-axis direction (winding axis direction).

[0300] The electrode assembly 80 can be manufactured by the winding method described with reference to Fig. 2. For ease of explanation, the protruding structure of the uncoated portions 43a and 43b extending outward from the separator is shown in detail, and the winding structure of the first electrode plate, the second electrode plate, and the separator is not shown. The uncoated portion 43a protruding upward extends from the first electrode plate, and the uncoated portion 43b protruding downward extends from the second electrode plate.

[0301] The varying heights of the uncoated portions 43a, 43b are shown only schematically. That is, the heights of the uncoated portions 43a, 43b may vary irregularly depending on the cutting position of the cross section. For example, if the sides of the trapezoidal segments 61, 61' are cut, the height of the uncoated portions in the cross section will be lower than the height of the segments 61, 61'. Therefore, it should be understood that the heights of the uncoated portions 43a, 43b shown in the cross-sectional views of the electrode assembly correspond to the average height of the uncoated portions included in each winding turn (C2 in FIG. 8, D2 in FIG. 10).

[0302] 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, an outer-periphery-side 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 outer-periphery-side uncoated portion B3.

[0303] The height (length in the Y-axis direction) of the outer uncoated portion B3 is relatively shorter than the height of the middle uncoated portion B2, which prevents the outer uncoated portion B3 from being pressed against the beading portion of the battery can, thereby preventing an internal short circuit.

[0304] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In one modified embodiment, the lower uncoated portion 43b may have a conventional electrode plate structure or an electrode plate structure of another embodiment (modified embodiment).

[0305] The ends 81 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery toward the core of the electrode assembly 80. In this case, the outer periphery uncoated portion B3 may not be substantially bent.

[0306] FIG. 12 is a cross-sectional view of a jelly-roll type electrode assembly 90 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), taken along the Y-axis direction (winding axis direction).

[0307] 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, an outer-periphery-side 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 outer-periphery-side uncoated portion B3.

[0308] The height of the outer uncoated portion B3 is relatively lower than that of the middle uncoated portion B2, and decreases gradually or in steps from the core side to the outer periphery, thereby preventing the outer uncoated portion B3 from being pressed against the beading portion of the battery can, which could cause an internal short circuit.

[0309] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In one modified embodiment, the lower uncoated portion 43b may have a conventional electrode plate structure or an electrode structure of another embodiment (modified embodiment).

[0310] Ends 91 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery toward the core of the electrode assembly 90. In this case, the outermost portion 92 of the outer periphery uncoated portion B3 may not be substantially bent.

[0311] FIG. 13 is a cross-sectional view of a jelly-roll type electrode assembly 100 in which any one of the electrode plates 50, 60, 70 of the third to fifth embodiments (modifications thereof) is applied to the first electrode plate (positive electrode plate) and the second electrode plate (negative electrode plate) along the Y-axis direction (winding axis direction).

[0312] Referring 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, an outer-periphery-side 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 outer-periphery-side uncoated portion B3.

[0313] The height of the core-side uncoated region B1 is relatively lower than that of the intermediate uncoated region B2. The height of the innermost uncoated region 43a in the intermediate uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side region.

[0314] Therefore, even if the middle uncoated portion B2 is bent, the bent portion does not block the cavity 102 in the core of the electrode assembly 100. If the cavity 102 is not blocked, the electrolyte injection process can be carried out without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the cavity 102 to easily perform the welding process between the negative electrode current collector plate and the battery can.

[0315] The height of the outer uncoated portion B3 is relatively lower than the height of the middle uncoated portion B2, which prevents the outer uncoated portion B3 from being pressed against the beading portion of the battery can, thereby preventing an internal short circuit from occurring.

[0316] In one modified embodiment, the height of the outer circumferential plain portion B3 may decrease gradually or in steps, unlike Fig. 13. Also, while the height of the intermediate plain portion B2 is uniform over a portion of the outer circumferential side in Fig. 13, the height of the intermediate plain portion B2 may increase gradually or in steps from the boundary between the core-side plain portion B1 and the intermediate plain portion B2 to the boundary between the intermediate plain portion B2 and the outer circumferential plain portion B3.

[0317] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In one modified embodiment, the lower uncoated portion 43b may have a conventional electrode plate structure or an electrode structure of another embodiment (modified embodiment).

[0318] The ends 101 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery side to the core side of the electrode assembly 100. At this time, the core-side uncoated portion B1 and the outer periphery-side uncoated portion B3 are not substantially bent.

[0319] When the middle plain portion B2 includes multiple segments, bending stress is alleviated, preventing tearing or abnormal deformation of the notch valley portion of the plain portion 43. Furthermore, when the width and / or height and / or spacing pitch of the segments are adjusted within the ranges of the numerical values ​​in the above-described embodiment, the segments overlap each other to an extent that sufficient welding strength is ensured as they are bent toward the core, and no open spaces (gaps) are formed on the bent surface (surface viewed from the Y-axis direction).

[0320] FIG. 14 is a cross-sectional view of an electrode assembly 110 according to another embodiment of the present invention, taken along the Y-axis direction (winding axis direction).

[0321] Referring to FIG. 14, the electrode assembly 110 is substantially identical in configuration to the electrode assembly 100 of FIG. 13, except that the height of the outer uncoated portion B3 is substantially the same as the outermost height of the middle uncoated portion B2.

[0322] The outer circumferential plain portion B3 may include a plurality of segment pieces. The configuration of the plurality of segment pieces is similarly described in the fourth and fifth embodiments (variants).

[0323] In the electrode assembly 110, the height of the core-side uncoated region B1 is relatively lower than the height of the middle uncoated region B2. The height H of the innermost uncoated region in the middle uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0324] Therefore, even if the middle uncoated portion B2 is bent, the bent portion does not block the cavity 112 in the core of the electrode assembly 110. If the cavity 112 is not blocked, the electrolyte injection process can be carried out without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the cavity 112 to easily perform the welding process between the negative electrode current collector plate and the battery can.

[0325] In one modified embodiment, the structure in which the height of the intermediate uncoated portion B2 increases gradually or in steps from the core side to the outer periphery side may be extended to the outer periphery side uncoated portion B3. In this case, the height of the uncoated portion 43a may increase gradually or in steps from the boundary between the core side uncoated portion B1 and the intermediate uncoated portion B2 to the outermost surface of the electrode assembly 110.

[0326] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In one modified embodiment, the lower uncoated portion 43b may have a conventional electrode plate structure or an electrode structure of another embodiment (modified embodiment).

[0327] The ends 111 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery side to the core side of the electrode assembly 110. At this time, the core-side uncoated portion B1 is not substantially bent.

[0328] When the middle uncoated region B2 and the outer uncoated region B3 include multiple segments, bending stress is alleviated, preventing tearing or abnormal deformation of the uncoated regions 43a, 43b near the notch valleys. Furthermore, when the width and / or height and / or spacing pitch of the segments are adjusted within the ranges of the above-described embodiments, the segments overlap each other to an extent that sufficient welding strength is ensured when they are bent toward the core, and no open spaces (gaps) are formed on the bent surfaces (surfaces viewed from the Y-axis direction).

[0329] FIG. 15 is a cross-sectional view of an electrode assembly 120 according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction).

[0330] Referring to FIG. 15, the electrode assembly 120 differs from the electrode assembly 100 of FIG. 13 only in that the height of the intermediate uncoated portion B2 has a pattern in which it gradually or stepwise increases and then decreases, but the other configurations are substantially the same.

[0331] Such a change in the height of the middle plain portion B2 can be achieved by adjusting the height of the staircase pattern (see FIG. 6) or the divided pieces (see FIG. 7a or FIG. 9a) included in the middle plain portion B2.

[0332] In the electrode assembly 120, the height of the core-side uncoated region B1 is relatively lower than the height of the middle uncoated region B2. The height H of the innermost uncoated region in the middle uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0333] Therefore, even if the middle uncoated portion B2 is bent toward the core side, the bent portion does not block the cavity 122 in the core of the electrode assembly 120. If the cavity 122 is not blocked, the electrolyte injection process is not hindered and the efficiency of the electrolyte injection is improved. In addition, a welding jig can be inserted through the cavity 122 to easily perform the welding process between the negative electrode current collector plate and the battery can.

[0334] In addition, the height of the outer uncoated portion B3 is relatively lower than the height of the middle uncoated portion B2. This prevents the outer uncoated portion B3 from being pressed against the beading of the battery can, which could cause an internal short circuit. In one modified embodiment, the height of the outer uncoated portion B3 may decrease gradually or in steps toward the outer periphery.

[0335] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In a modified embodiment, the lower uncoated portion 43b may have a conventional electrode plate structure or an electrode structure of another embodiment (modified embodiment).

[0336] The ends 121 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery side to the core side of the electrode assembly 120. At this time, the core-side uncoated portion B1 and the outer periphery-side uncoated portion B3 are not substantially bent.

[0337] When the middle plain portion B2 includes multiple segments, bending stress is alleviated, preventing tearing or abnormal deformation of the plain portions 43a, 43b. Furthermore, when the width and / or height and / or spacing pitch of the segments are adjusted within the ranges of the above-described embodiments, the segments overlap each other to an extent that sufficient welding strength is ensured when they are bent toward the core, and no open spaces (gaps) are formed on the bent surfaces (surfaces viewed from the Y-axis direction).

[0338] FIG. 16 is a cross-sectional view of an electrode assembly 130 according to yet another embodiment of the present invention, taken along the Y-axis direction (winding axis direction).

[0339] Referring to Figure 16, the electrode assembly 130 differs from the electrode assembly 120 of Figure 15 in that the height of the outer uncoated portion B3 has a pattern in which the height gradually or stepwise decreases from the boundary between the outer uncoated portion B3 and the intermediate uncoated portion B2 toward the outermost surface of the electrode assembly 130, but the other configurations are substantially identical.

[0340] This height variation of the outer uncoated portion B3 can be achieved by extending the staircase pattern (see FIG. 6) included in the intermediate uncoated portion B2 to the outer uncoated portion B3 and gradually or stepwise decreasing the height of the pattern toward the outer periphery. In another modified embodiment, the height variation of the outer uncoated portion B3 can be achieved by extending the segmented structure of the intermediate uncoated portion B2 to the outer periphery uncoated portion B3 and gradually or stepwise decreasing the height of the segmented structure toward the outer periphery.

[0341] In the electrode assembly 130, the height of the core-side uncoated region B1 is relatively lower than the height of the middle uncoated region B2. The height H of the innermost uncoated region in the middle uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0342] Therefore, even if the middle uncoated portion B2 is bent toward the core, the bent portion does not block the cavity 132 in the core of the electrode assembly 120. If the cavity 132 is not blocked, the electrolyte injection process is not hindered and the efficiency of the electrolyte injection is improved. In addition, a welding jig can be inserted through the cavity 132 to easily perform the welding process between the negative electrode current collector plate and the battery can.

[0343] The lower uncoated portion 43b has the same structure as the upper uncoated portion 43a. In one modified embodiment, the lower uncoated portion 43b may have a conventional electrode plate structure or an electrode structure of another embodiment (modified embodiment).

[0344] The ends 131 of the upper uncoated portion 43a and the lower uncoated portion 43b may be bent from the outer periphery side to the core side of the electrode assembly 130. At this time, the core-side uncoated portion B1 is not substantially bent.

[0345] When the central uncoated portion B2 and the outer uncoated portion B3 include multiple segments, bending stress is alleviated, preventing tearing or abnormal deformation of the notch valleys of the uncoated portions 43a, 43b. Furthermore, when the width and / or height and / or spacing pitch of the segments are adjusted within the ranges of the above-described embodiments, the segments overlap each other to an extent that sufficient welding strength is ensured when they are bent toward the core, and no open spaces (gaps) are formed on the bent surfaces (surfaces viewed from the Y-axis direction).

[0346] Various electrode assembly structures according to embodiments of the present invention are applicable to jelly-roll type cylindrical battery cells.

[0347] Preferably, the cylindrical battery cell may be, for example, a cylindrical battery cell having a form factor ratio (defined as the diameter of a cylindrical battery cell divided by its height, i.e., the ratio of height (H) to diameter (Φ)) greater than about 0.4.

[0348] Here, the term "form factor" refers to a value indicating the diameter and height of a cylindrical battery cell. Cylindrical battery cells according to an embodiment of the present invention may be, for example, 46110 cells, 48750 cells, 48110 cells, 48800 cells, or 46800 cells. In the form factor number, the first two digits indicate the diameter of the cell, the next two digits indicate the height of the cell, and the final digit "0" indicates that the cross section of the cell is circular.

[0349] When an electrode assembly having a tabless structure is applied to a cylindrical battery cell having a form factor ratio exceeding 0.4, the stress applied in the radial direction when the plain portion is bent increases, making the plain portion prone to tearing. Furthermore, when welding a current collector plate to the bent surface of the plain portion, the number of overlapping layers of the plain portion must be increased to ensure sufficient welding strength and reduce resistance. These requirements can be met by the electrode plate and electrode assembly according to an embodiment (variant) of the present invention.

[0350] A battery cell according to one embodiment of the present invention may be a cylindrical battery cell that is approximately cylindrical, having a diameter of about 46 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0351] A battery cell according to another embodiment may be a cylindrical battery cell that is a generally cylindrical cell having a diameter of about 48 mm, a height of about 75 mm, and a form factor ratio of 0.640.

[0352] A battery cell according to yet another embodiment may be a cylindrical battery cell that is a generally cylindrical cell having a diameter of about 48 mm, a height of about 110 mm, and a form factor ratio of 0.418.

[0353] A battery cell according to yet another embodiment may be a cylindrical battery cell that is substantially cylindrical, having a diameter of about 48 mm, a height of about 80 mm, and a form factor ratio of 0.600.

[0354] A battery cell according to yet another embodiment may be a cylindrical battery cell that is a generally cylindrical cell having a diameter of about 46 mm, a height of about 80 mm, and a form factor ratio of 0.575.

[0355] Conventionally, battery cells with a form factor ratio of approximately 0.4 or less have been used. For example, 18650 cells and 21700 cells have been used. 18650 cells have a diameter of approximately 18 mm, a height of approximately 65 mm, and a form factor ratio of 0.277. 21700 cells have a diameter of approximately 21 mm, a height of approximately 70 mm, and a form factor ratio of 0.300.

[0356] Hereinafter, a cylindrical battery cell according to an embodiment of the present invention will be described in detail.

[0357] FIG. 17 is a cross-sectional view of a cylindrical battery cell 140 according to an embodiment of the present invention taken along the Y-axis direction.

[0358] Referring to FIG. 17, a cylindrical battery cell 140 according to one embodiment of the present invention includes an electrode assembly 141 including a first electrode plate, a separator, and a second electrode plate, a battery can 142 that houses the electrode assembly 141, and a seal 143 that seals the open end of the battery can 142.

[0359] The battery can 142 is a cylindrical container with 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 141 in the inner space through the opening at the top, along with the electrolyte.

[0360] The electrolyte is A + B - where A + Li + , Na + , K. +or a combination thereof. - is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , BF2C2O4 - , BC4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The anion comprises one or more anions selected from the group consisting of:

[0361] The electrolyte may be dissolved in an organic solvent. The organic solvent is not limited to a specific component, as long as it can be used as a solvent for the electrolyte of an electrochemical device. For example, carbonate solvents such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or mixtures thereof may be used.

[0362] The electrode assembly 141 may have a jelly roll structure. As shown in Fig. 2, the electrode assembly 141 may be manufactured by sequentially stacking a lower separator, a first electrode plate, an upper separator, and a second electrode plate at least once, and winding the stack around a winding center C.

[0363] The first and second electrode plates have opposite polarities. That is, one has a positive polarity and the other has a negative polarity. At least one of the first and second electrode plates may have an electrode plate structure according to the above-described embodiment (variant). The other of the first and second electrode plates may have a conventional electrode plate structure or an electrode plate structure according to the embodiment (variant).

[0364] An uncoated portion 146a of the first electrode plate and an uncoated portion 146b of the second electrode plate protrude from the top and bottom of the electrode assembly 141, respectively. The first electrode plate has the electrode plate structure of the first embodiment (variant). Therefore, the height of the uncoated portion 146a of the first electrode plate is lower than the height of the uncoated portions of other parts. The uncoated portion B3 of the first electrode plate is spaced a predetermined distance from the inner circumferential surface of the battery can 142, particularly the beading portion 147. Therefore, the uncoated portion B3 of the first electrode plate does not contact the battery can 142, which is electrically connected to the second electrode plate, preventing an internal short circuit in the battery cell 140.

[0365] The uncoated portion 146b of the second electrode plate has the same height. In a modified embodiment, 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 modified embodiment, the uncoated portion 146b of the second electrode plate may selectively have the structure of the uncoated portion of the electrode plate according to the embodiment (modified embodiment).

[0366] The sealing body 143 may include a cap plate 143a, a first gasket 143b having insulating properties and providing airtightness between the cap plate 143a and the battery can 142, and a connecting plate 143c electrically and mechanically connected to the cap plate 143a.

[0367] The cap plate 143a is a component made of a conductive metal material and covers the upper opening of the battery can 142. The cap plate 143a is electrically connected to the uncoated portion 146a of the first electrode plate and is electrically insulated from the battery can 142 via the first gasket 143b. Therefore, the cap plate 143a can function as a first electrode terminal of the cylindrical battery cell 140.

[0368] The cap plate 143a is placed on a beading portion 147 formed on the battery can 142 and fixed by a crimping portion 148. A first gasket 143b may be interposed between the cap plate 143a and the crimping portion 148 to ensure airtightness of the battery can 142 and to provide electrical insulation between the battery can 142 and the cap plate 143a. The cap plate 143a may have a protrusion 143d formed to protrude upward from the center thereof.

[0369] The battery can 142 is electrically connected to the uncoated portion 146b of the second electrode plate. Therefore, 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.

[0370] The battery can 142 has a beading portion 147 and a crimping portion 148 at its upper end. The beading portion 147 is formed by pressing in around the outer periphery of the battery can 142. The beading portion 147 prevents the electrode assembly 141 housed inside the battery can 142 from slipping out of the upper opening of the battery can 142, and also functions as a support on which the sealing body 143 is placed.

[0371] The inner circumferential surface of the beading portion 147 is spaced a predetermined distance from the outer uncoated portion B3 of the first electrode plate. More specifically, the lower end of the inner circumferential surface of the beading portion 147 is spaced a predetermined distance from the outer uncoated portion B3 of the first electrode plate. Furthermore, because the height of the outer uncoated portion B3 is low, the outer uncoated portion B3 is substantially unaffected even when the battery can 142 is pressed from the outside to form the beading portion 147. Therefore, the outer uncoated portion B3 is not pressed by other components such as the beading portion 147, which prevents partial deformation of the electrode assembly 141 and internal short circuits in the cylindrical battery cell 140.

[0372] Preferably, the relationship "D1≦D2" is satisfied, where D1 is the pressing depth of the beading portion 147 and D2 is the radial distance from the inner circumferential surface of the battery can 142 to the boundary between the outer uncoated portion B3 and the intermediate uncoated portion B2. In this case, damage to the outer uncoated portion B3 is substantially prevented when the battery can 142 is pressed in to form the beading portion 147.

[0373] The crimping portion 148 is formed on the upper portion of the beading portion 147. The crimping portion 148 is extended and bent to enclose the outer circumferential surface of the cap plate 143a disposed on the beading portion 147 and a portion of the upper surface of the cap plate 143a.

[0374] The cylindrical battery cell 140 may further include a first current collector 144 and / or a second current collector 145 and / or an insulator 146 .

[0375] The first current collecting plate 144 is coupled to the upper part of the electrode assembly 141. The first current collecting plate 144 is made of a conductive metal material such as aluminum, copper, or nickel, and is electrically connected to the uncoated portion 146a of the first electrode plate. A lead 149 may be connected to the first current collecting plate 144. The lead 149 may extend above the electrode assembly 141 and be coupled to the connecting plate 143c, or may be directly coupled to the lower surface of the cap plate 143a. The lead 149 may be coupled to other components by welding.

[0376] Preferably, the first current collector 144 may be integrally formed with the lead 149. In this case, the lead 149 may be in the form of a long plate extending outward from the center of the first current collector 144.

[0377] The first current collecting plate 144 may have a plurality of radially formed concaves and convexes (not shown) on its lower surface. When the radial concaves and convexes are provided, the first current collecting plate 144 may be pressed against the concaves and convexes to press the uncoated portion 146a of the first electrode plate into the concaves and convexes.

[0378] The first current collecting plate 144 is coupled to an end of the uncoated portion 146a of the first electrode plate. The uncoated portion 146a and the first current collecting plate 144 may be coupled together by, for example, laser welding. Laser welding may be performed by partially melting the base material of the current collecting plate. In a modified embodiment, the first current collecting plate 144 and the uncoated portion 146a may be welded together using solder. In this case, the solder may have a lower melting point than the first current collecting plate 144 and the uncoated portion 146a. Laser welding may be replaced by resistance welding, ultrasonic welding, or the like.

[0379] A second current collecting plate 145 may be coupled to the lower surface of the electrode assembly 141. One surface of the second current collecting plate 145 may be coupled to the uncoated portion 146b of the second electrode plate by welding, and the other surface may be coupled to the inner bottom surface of the battery can 142 by welding. The coupling structure between the second current collecting plate 145 and the uncoated portion 146b of the second electrode plate may be substantially the same as the coupling structure between the first current collecting plate 144 and the uncoated portion 146a of the first electrode plate.

[0380] The uncoated portions 146a and 146b are not limited to the structure shown in the drawings. Therefore, the uncoated portions 146a and 146b may selectively have the structure of the uncoated portions of the electrode plates according to the embodiment (variant) as well as the structure of the conventional uncoated portions.

[0381] The insulator 146 may cover the first current collector 144. By covering the first current collector 144 on the upper surface of the first current collector 144, the insulator 146 can prevent direct contact between the first current collector 144 and the inner circumferential surface of the battery can 142.

[0382] The insulator 146 has a lead hole 151 through which the lead 149 extending upward from the first current collector plate 144 is drawn out. The lead 149 is drawn upward through the lead hole 151 and coupled to the lower surface of the connecting plate 143c or the lower surface of the cap plate 143a.

[0383] The peripheral region of the insulator 146 may be interposed between the first current collecting plate 144 and the beading portion 147 to fix the combination of the electrode assembly 141 and the first current collecting plate 144. This limits the movement of the combination of the electrode assembly 141 and the first current collecting plate 144 in the height direction of the battery cell 140, thereby improving the assembly stability of the battery cell 140.

[0384] The insulator 146 may be made of an insulating polymer resin. As an example, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0385] The battery can 142 may further include a vent 152 formed on its bottom surface. The vent 152 corresponds to a region on the bottom surface of the battery can 142 that is thinner than the surrounding region. The vent 152 is structurally weaker than the surrounding region. Therefore, if an abnormality occurs in the cylindrical battery cell 140 and the internal pressure increases above a certain level, the vent 152 may burst, causing gas generated inside the battery can 142 to be released to the outside.

[0386] The venting portion 152 may be formed continuously or discontinuously in a circle on the bottom surface of the battery can 142. In a variant, the venting portion 152 may be formed in a linear pattern or in any other pattern.

[0387] FIG. 18 is a cross-sectional view of a cylindrical battery cell 150 according to another embodiment of the present invention, taken along the Y-axis direction.

[0388] Referring to FIG. 18, the cylindrical battery cell 150 is substantially identical in configuration to the cylindrical battery cell 140 of FIG. 17, except that the uncoated portion 146a of the first electrode plate employs the electrode plate structure of the second embodiment (variant form).

[0389] 18, the uncoated portion 146a of the first electrode plate may have a shape in which the height of the outer uncoated portion B3 gradually or stepwise decreases toward the inner circumferential surface of the battery can 142. Preferably, an imaginary line connecting the uppermost ends of the outer uncoated portions B3 may have the same or similar shape as the inner circumferential surface of the beading portion 147.

[0390] The outer uncoated portion B3 has an inclined surface, which prevents the outer uncoated portion B3 from being damaged by the beading portion 147 when the battery can 142 is pressed in to form the beading portion 147. This also prevents the outer uncoated portion B3 from coming into contact with the battery can 142 of the opposite polarity, which could cause an internal short circuit.

[0391] Other configurations of the cylindrical battery cell 150 are substantially the same as those of the above-described embodiment (variant).

[0392] The uncoated portions 146a and 146b are not limited to the structure shown in the drawings. Therefore, the uncoated portions 146a and 146b may selectively have the structure of the uncoated portions of the electrode plates according to the embodiment (variant) as well as the structure of the conventional uncoated portions.

[0393] FIG. 19 is a cross-sectional view of a cylindrical battery cell 160 according to yet another embodiment of the present invention, taken along the Y-axis direction.

[0394] Referring to FIG. 19, the cylindrical battery cell 160 is substantially identical in configuration to the cylindrical battery cells 140 and 150 described above, except that the lead 149 connected to the first current collector 144 is directly connected to the cap plate 143a of the sealing body 143 through the lead hole 151 of the insulator 146, and the insulator 146 and the first current collector 144 are in close contact with the lower surface of the cap plate 143a.

[0395] In the cylindrical battery cell 160, the diameter of the first current collector 144 and the outermost diameter of the middle uncoated portion B2 are smaller than the smallest inner diameter of the battery can 142. In addition, the diameter of the first current collector 144 may be the same as or larger than the outermost diameter of the middle uncoated portion B2.

[0396] 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 beading portion 147 is formed. In this case, the outermost diameters of the first current collector 144 and the middle uncoated portion B2 are smaller than the inner diameter of the battery can 142 at the position where the beading portion 147 is formed. In addition, the diameter of the first current collector 144 may be the same as or larger than the outermost diameter of the middle uncoated portion B2. The peripheral region of the insulator 146 may be folded downward and interposed between the outer uncoated portion B3 and the beading portion 147 to fix the combination of the electrode assembly 141 and the first current collector 144.

[0397] Preferably, the insulator 146 includes a portion covering the outer uncoated portion B3 and a portion covering the first current collecting plate 144, and the portion connecting these two portions may be curved together to correspond to the curved shape of the beading portion 147. The insulator 146 may insulate the outer uncoated portion B3 from the inner circumferential surface of the beading portion 147, and may also insulate the first current collecting plate 144 from the inner circumferential surface of the beading portion 147.

[0398] The first current collecting plate 144 may be positioned higher than the lower end of the beading portion 147 and may be bonded to the core-side uncoated portion B1 and the middle uncoated portion B2. In this case, the pressing depth D1 of the beading portion 147 is equal to or smaller than the distance D2 from the inner circumferential surface of the battery can 142 to the boundary between the outer-side 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 collecting plate 144 bonded thereto may be positioned higher than the lower end of the beading portion 147. The lower end of the beading portion 147 refers to a reference line portion located between the beading portion 147 and the portion of the battery can 142 in which the electrode assembly 141 is housed.

[0399] Because the core-side uncoated portion B1 and the middle uncoated portion B2 occupy the radially inner space of the beading portion 147, the empty space between the electrode assembly 141 and the cap plate 143a is minimized. In addition, the connecting plate 143c, which was previously located in the empty space between the electrode assembly 141 and the cap plate 143a, is omitted. Therefore, the lead 149 of the first current collector 144 can be directly connected to the underside of the cap plate 143a. This structure reduces the empty space within the battery cell, allowing the energy density to be maximized by the reduced empty space.

[0400] In the cylindrical battery cell 160, the first current collector plate 144 and the second current collector plate 145 may be welded to the ends of the uncoated portions 146a and 146b, respectively, similar to the above-described embodiments.

[0401] The uncoated portions 146a and 146b are not limited to the structure shown in the drawings. Therefore, the uncoated portions 146a and 146b may selectively have the structure of the uncoated portions of the electrode plates according to the embodiment (variant) as well as the structure of the conventional uncoated portions.

[0402] FIG. 20 is a cross-sectional view of a cylindrical battery cell 170 according to yet another embodiment of the present invention taken along the Y axis.

[0403] Referring to FIG. 20, the cylindrical battery cell 170 differs from the cylindrical battery cell 140 shown in FIG. 17 in that the structure of the electrode assembly is substantially the same, but other structures except for the electrode assembly have been changed.

[0404] Specifically, the cylindrical battery cell 170 includes a battery can 171 having a rivet terminal 172 inserted therethrough. The rivet terminal 172 is attached to the closed surface (top surface in the drawing) of the battery can 171. The rivet terminal 172 is riveted into a through-hole in the battery can 171 with a second insulating gasket 173 interposed therebetween. The rivet terminal 172 is exposed to the outside in the direction opposite to the direction of gravity.

[0405] The rivet terminal 172 includes a terminal exposure portion 172a and a terminal insertion portion 172b. The terminal exposure portion 172a is exposed to the outside of the closed surface of the battery can 171. The terminal exposure portion 172a may be located approximately at the center of the closed surface of the battery can 171. The maximum diameter of the terminal exposure portion 172a may be larger than the maximum diameter of the through-hole formed in the battery can 171. The terminal insertion portion 172b may penetrate approximately the center of the closed surface of the battery can 171 to be electrically connected to the uncoated portion 146a of the first electrode plate. The terminal insertion portion 172b may be rivet-connected to the inner surface of the battery can 171. That is, an end of the terminal insertion portion 172b may be 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 through-hole in the battery can 171.

[0406] The lower end surface of the terminal insertion portion 172b may be welded to the first current collecting plate 144 connected to the uncoated portion 146a of the first electrode plate. An insulating cap 174 made of an insulating material may be interposed between the first current collecting plate 144 and the inner surface of the battery can 171. The insulating cap 174 covers the upper portion of the first current collecting plate 144 and the upper peripheral edge of the electrode assembly 141. This prevents the outer uncoated portion B3 of the electrode assembly 141 from coming into contact with the inner surface of the battery can 171, which has the opposite polarity, and causing a short circuit. The terminal insertion portion 172b of the rivet terminal 172 may penetrate the insulating cap 174 and be welded to the first current collecting plate 144.

[0407] The second gasket 173 is interposed between the battery can 171 and the rivet terminal 172 to prevent electrical contact between the battery can 171 and the rivet terminal 172, which have opposite polarities. This allows the upper surface of the battery can 171, which has a substantially flat shape, to function as a second electrode terminal of the cylindrical battery cell 170.

[0408] The second gasket 173 includes a gasket exposing portion 173a and a gasket inserting portion 173b. The gasket exposing portion 173a is interposed between the terminal exposing portion 172a of the rivet terminal 172 and the battery can 171. The gasket inserting portion 173b is interposed between the terminal inserting portion 172b of the rivet terminal 172 and the battery can 171. The gasket inserting portion 173b may be deformed when the terminal inserting portion 172b is riveted, and may be tightly attached to the inner surface of the battery can 171. The second gasket 173 may be made of, for example, an insulating polymer resin.

[0409] The gasket exposing portion 173a of the second gasket 173 may extend to cover the outer peripheral surface of the terminal exposing portion 172a of the rivet terminal 172. When the second gasket 173 covers the outer peripheral surface of the rivet terminal 172, it is possible to prevent a short circuit from occurring during the process of connecting an electrical connection part, such as a bus bar, to the upper surface of the battery can 171 and / or the rivet terminal 172. Although not shown, the gasket exposing portion 173a may extend to cover not only the outer peripheral surface of the terminal exposing portion 172a but also a portion of the upper surface.

[0410] When the second gasket 173 is made of a polymer resin, the second gasket 173 may be joined to the battery can 171 and the rivet terminal 172 by heat sealing. In this case, the airtightness at the joining interface between the second gasket 173 and the rivet terminal 172 and at the joining interface between the second gasket 173 and the battery can 171 is strengthened. Meanwhile, when the gasket exposed portion 173a of the second gasket 173 has a shape that extends to the upper surface of the terminal exposed portion 172a, the rivet terminal 172 may be joined integrally with the second gasket 173 by insert injection.

[0411] The remaining area 175 on the top surface of the battery can 171 excluding the area occupied by the rivet terminal 172 and the second gasket 173 corresponds to a second electrode terminal having a polarity opposite to that of the rivet terminal 172 .

[0412] The second current collecting plate 176 is coupled to the lower part of the electrode assembly 141. The second current collecting 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.

[0413] Preferably, the second current collector 176 is electrically connected to the battery can 171. Therefore, the second current collector 176 may be fixed with at least a portion of its peripheral edge interposed between the inner surface of the battery can 171 and the first gasket 178b. In one example, at least a portion of the peripheral edge of the second current collector 176 may be fixed to the beading portion 180 by welding while being supported on the lower end surface of the beading portion 180 formed at the lower end of the battery can 171. In a modified embodiment, at least a portion of the peripheral edge of the second current collector 176 may be directly welded to the inner wall surface of the battery can 171.

[0414] The second current collecting plate 176 may have a plurality of projections and recesses (not shown) formed radially on the surface facing the non-coated portion 146b. When the projections and recesses are formed, the second current collecting plate 176 may be pressed against the projections and recesses to press the non-coated portion 146b into the projections and recesses.

[0415] Preferably, the second current collector plate 176 and the end of the non-coating portion 146b can be joined by welding, for example, laser welding.

[0416] The sealing body 178 that seals the lower open end of the battery can 171 includes a cap plate 178a and a first gasket 178b. The first gasket 178b electrically isolates the cap plate 178a from the battery can 171. A crimping portion 181 secures the periphery of the cap plate 178a and the first gasket 178b together. The cap plate 178a is provided with a vent portion 179. The configuration of the vent portion 179 is substantially the same as in the above-described embodiment (variant).

[0417] Preferably, the cap plate 178a is made of a conductive metal material. However, the cap plate 178a does not have electrical polarity because the first gasket 178b is interposed between the cap plate 178a and the battery can 171. The seal 178 seals the open end of the lower part of the battery can 171 and functions to release gas when the internal pressure of the battery cell 170 increases above a critical value.

[0418] Preferably, the rivet terminal 172 electrically connected to the uncoated portion 146a of the first electrode plate is used as the first electrode terminal. Furthermore, a portion 175 of the upper surface of the battery can 171, excluding the rivet terminal 172, electrically connected to the uncoated portion 146b of the second electrode plate via the second current collector plate 176 is used as a second electrode terminal having the opposite polarity to the first electrode terminal. When two electrode terminals are located on the upper portion of the cylindrical battery cell 170, electrical connection components such as bus bars can be disposed on only one side of the cylindrical battery cell 170. This can simplify the battery pack structure and improve energy density. Furthermore, the portion 175 used as the second electrode terminal has a substantially flat shape, ensuring a sufficient bonding area when bonding electrical connection components such as bus bars. This allows the cylindrical battery cell 170 to reduce resistance at the bonding locations of the electrical connection components to a desirable level.

[0419] Meanwhile, the structure of the electrode assembly 141 and the structure of the uncoated portion are not limited to those shown in the drawings, and may be replaced with the structures of the above-described embodiments (variations).

[0420] FIG. 21 is a cross-sectional view of a cylindrical battery cell 180 according to yet another embodiment of the present invention taken along the Y axis.

[0421] Referring to FIG. 21, the cylindrical battery cell 180 has substantially the same structure as the cylindrical battery cell 150 shown in FIG. 18 in terms of the electrode assembly 141, and other configurations except for the electrode assembly 141 are substantially the same as the cylindrical battery cell 170 shown in FIG. 20.

[0422] Therefore, the configurations of the embodiments (variations) of the cylindrical battery cells 150 and 170 can be similarly applied to the cylindrical battery cell 180.

[0423] Furthermore, the structure of the electrode assembly 141 and the structure of the uncoated portion are not limited to those shown in the drawings, and may be replaced with the structures of the above-described embodiments (variations).

[0424] FIG. 22 is a cross-sectional view of a cylindrical battery cell 190 according to yet another embodiment of the present invention taken along the Y axis.

[0425] Referring to FIG. 22, a cylindrical battery cell 190 includes the electrode assembly 110 shown in FIG. 14, and other configurations except for the electrode assembly 110 are substantially identical to the cylindrical battery cell 140 shown in FIG.

[0426] 22, uncoated portions 146a and 146b of electrode assembly 110 are bent from the outer periphery toward the core. At this time, core-side uncoated portion B1 is not substantially bent because it is lower than the other portions. First current collecting plate 144 may be welded to the bent surface of uncoated portion 146a, and second current collecting plate 145 may be welded to the bent surface of uncoated portion 146b. The bent surfaces may be formed at the top and bottom of electrode assembly 110, respectively, as the uncoated portions 146a and 146b overlap each other when they are bent.

[0427] In the electrode assembly 110, the height of the core-side uncoated region B1 is relatively lower than the other regions. Also, as shown in Figure 14, the height H of the innermost uncoated region in the middle uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0428] Therefore, even if the non-coating portion 146a is bent toward the core side, the cavity 112 of the core of the electrode assembly 110 is not closed and can be open at the top.

[0429] If the cavity 112 is not blocked, the electrolyte injection process can be carried out without any problems, improving the efficiency of the electrolyte injection process. In addition, a welding jig can be inserted through the cavity 112 to easily weld the second current collector plate 145 and the battery can 142 together.

[0430] When the plain portions 146a, 146b have a divided structure, if the width and / or height and / or spacing pitch of the divided pieces are adjusted to satisfy the numerical range of the above-mentioned embodiment, when the divided pieces are bent, the divided pieces overlap each other to an extent that sufficient welding strength can be ensured, and no empty space (gap) is formed on the bent surface.

[0431] The structure of the uncoated portions 146a, 146b may be modified without limitation to the structure according to the above-described embodiment (variant), and there is no restriction on applying a conventional uncoated portion structure to either one of the uncoated portions 146a, 146b.

[0432] FIG. 23 is a cross-sectional view of a cylindrical battery cell 200 according to yet another embodiment of the present invention taken along the Y axis.

[0433] Referring to FIG. 23, a cylindrical battery cell 200 includes the electrode assembly 110 shown in FIG. 14, and other configurations except for the electrode assembly 110 are substantially identical to the cylindrical battery cell 180 shown in FIG. 21.

[0434] 23, the uncoated portions 146a and 146b of the electrode assembly 110 are bent from the outer periphery toward the core. At this time, the core-side uncoated portion B1 is not substantially bent because its height is lower than the other portions. The first current collector 144 may be welded to the bent surface of the uncoated portion 146a, and the second current collector 176 may be welded to the bent surface of the uncoated portion 146b.

[0435] In the electrode assembly 110, the height of the core-side uncoated region B1 is relatively lower than the other regions. Also, as shown in Figure 14, the height H of the innermost uncoated region in the middle uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0436] Therefore, even if the uncoated portions 146a and 146b are bent toward the core side, the cavity 112 of the core of the electrode assembly 110 is not closed and can be open at the top.

[0437] If the cavity 112 is not blocked, the electrolyte injection process can be carried out without any problems, improving the efficiency of the electrolyte injection. In addition, a welding jig can be inserted through the cavity 112 to easily weld the second current collector plate 176 and the battery can 171 together.

[0438] When the plain portions 146a, 146b have a divided structure, if the width and / or height and / or spacing pitch of the divided pieces are adjusted to satisfy the numerical range of the above-mentioned embodiment, when the divided pieces are bent, the divided pieces overlap each other to an extent that sufficient welding strength can be ensured, and no empty space (gap) is formed on the bent surface.

[0439] The structure of the uncoated portions 146a, 146b may be modified without limitation to the structure according to the above-described embodiment (variant), and there is no restriction on applying a conventional uncoated portion structure to either one of the uncoated portions 146a, 146b.

[0440] FIG. 24 is a cross-sectional view of a cylindrical battery cell 210 according to yet another embodiment of the present invention taken along the Y axis.

[0441] Referring to FIG. 24, a cylindrical battery cell 210 includes the electrode assembly 100 shown in FIG. 13, and other configurations except for the electrode assembly 100 are substantially identical to the cylindrical battery cell 140 shown in FIG. 17.

[0442] Preferably, the uncoated portions 146a and 146b of the electrode assembly 100 are bent from the outer periphery toward the core. At this time, the core-side uncoated portion B1 and the outer periphery-side uncoated portion B3 of the uncoated portion 146a are not substantially bent because they are lower in height than the other portions. The same applies to the uncoated portion 146b. The first current collecting plate 144 may be welded to the bent surface of the uncoated portion 146a, and the second current collecting plate 145 may be welded to the bent surface of the uncoated portion 146b.

[0443] The height of the core-side uncoated region B1 is relatively lower than that of the intermediate uncoated region B2. Also, as shown in Figure 14, the height H of the innermost uncoated region in the intermediate uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0444] Therefore, even if the uncoated portions 146a and 146b are bent toward the core side, the cavity 102 of the core of the electrode assembly 100 is not closed and can be open at the top.

[0445] If the cavity 102 is not blocked, the electrolyte injection process can be carried out without any problems, improving the efficiency of the electrolyte injection process. In addition, a welding jig can be inserted through the cavity to easily weld the second current collector plate 145 and the battery can 142 together.

[0446] In addition, the height of outer uncoated portion B3 is relatively lower than that of intermediate uncoated portion B2. Therefore, when uncoated portion 146a is bent, outer uncoated portion B3 is not substantially bent. In addition, outer uncoated portion B3 is sufficiently spaced apart from beading portion 147, which solves the problem of outer uncoated portion B3 being damaged when beading portion 147 is pressed in.

[0447] When the plain portions 146a, 146b have a divided structure, if the width and / or height and / or spacing pitch of the divided pieces are adjusted to satisfy the numerical range of the above-mentioned embodiment, when the divided pieces are bent, the divided pieces overlap each other to an extent that sufficient welding strength can be ensured, and no empty space (gap) is formed on the bent surface.

[0448] The structure of the uncoated portions 146a, 146b may be modified without limitation to the structure according to the above-described embodiment (variant), and there is no restriction on applying a conventional uncoated portion structure to either one of the uncoated portions 146a, 146b.

[0449] FIG. 25 is a cross-sectional view of a cylindrical battery cell 220 according to yet another embodiment of the present invention taken along the Y axis.

[0450] Referring to FIG. 25, a cylindrical battery cell 220 includes the electrode assembly 100 shown in FIG. 13, and other configurations except for the electrode assembly 100 are substantially the same as the cylindrical battery cell 180 shown in FIG.

[0451] Preferably, the uncoated portions 146a and 146b of the electrode assembly 100 are bent from the outer periphery toward the core. At this time, the core-side uncoated portion B1 of the uncoated portion 146a is not substantially bent because its height is lower than the other portions. The same applies to the uncoated portion 146b. The first current collector 144 may be welded to the bent surface of the uncoated portion 146a, and the second current collector 176 may be welded to the bent surface of the uncoated portion 146b.

[0452] In the electrode assembly 100, the height of the core-side uncoated region B1 is relatively lower than that of the middle uncoated region B2. Also, as shown in Figure 14, the height H of the innermost uncoated region in the middle uncoated region B2 is equal to or shorter than the radial length R of the core-side uncoated region B1. Here, the height of the uncoated region refers to the length or segment from the reference line DL to the first side.

[0453] Therefore, even if the uncoated portion 146a is bent toward the core side, the cavity 102 of the core of the electrode assembly 100 is not closed and can be open at the top.

[0454] If the cavity 102 is not blocked, the electrolyte injection process can be carried out without any problems, improving the efficiency of the electrolyte injection process. In addition, a welding jig can be inserted through the cavity 102 to easily perform the welding process between the second current collector plate 176 and the battery can 171.

[0455] Furthermore, the height of outer uncoated portion B3 of uncoated portion 146a is relatively smaller than that of intermediate uncoated portion B2. Therefore, when uncoated portion 146a is folded, outer uncoated portion B3 is not substantially folded. The same is true for uncoated portion 146b.

[0456] When the plain portions 146a, 146b have a divided structure, if the width and / or height and / or spacing pitch of the divided pieces are adjusted to satisfy the numerical range of the above-mentioned embodiment, when the divided pieces are bent, the divided pieces overlap each other to an extent that sufficient welding strength can be ensured, and no empty space (gap) is formed on the bent surface.

[0457] The structure of the uncoated portions 146a, 146b may be modified without limitation to the structure according to the above-described embodiment (variant), and there is no restriction on applying a conventional uncoated portion structure to either one of the uncoated portions 146a, 146b.

[0458] The cylindrical battery cells according to the above-described embodiments (variations) can be used to manufacture battery packs.

[0459] FIG. 26 is a diagram schematically illustrating the configuration of a battery pack according to one embodiment of the present invention.

[0460] 26, a battery pack 300 according to one embodiment of the present invention includes an assembly of electrically connected cylindrical battery cells 301 and a pack housing 302 that accommodates the assembly. The cylindrical battery cells 301 may be any one of the battery cells according to the above-described embodiments (variants). For convenience of illustration, components such as bus bars for electrically connecting the cylindrical battery cells 301, a cooling unit, and external terminals are not shown.

[0461] The battery pack 300 may be installed in a vehicle, which may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, including a four-wheeled vehicle or a two-wheeled vehicle.

[0462] FIG. 27 is a diagram illustrating a vehicle including the battery pack 300 of FIG.

[0463] 27, a vehicle V according to an embodiment of the present invention includes a battery pack 300 according to an embodiment of the present invention. The vehicle V operates by receiving power from the battery pack 300 according to an embodiment of the present invention.

[0464] According to one aspect of the present invention, the uncoated portions protruding from the upper and lower sides of the electrode assembly are used as electrode tabs, thereby reducing the internal resistance of a cylindrical battery cell and increasing the energy density.

[0465] According to another aspect of the present invention, by improving the structure of the uncoated portion of the electrode assembly, interference between the electrode assembly and the inner surface of the battery can does not occur during the process of forming the beading portion of the battery can, thereby preventing an internal short circuit in a cylindrical battery cell due to partial deformation of the electrode assembly.

[0466] According to yet another aspect of the present invention, the structure of the uncoated portion of the electrode assembly is improved to prevent the uncoated portion from tearing near the notch valley when the uncoated portion is bent, and the number of overlapping layers of the uncoated portion can be sufficiently increased to improve weld strength.

[0467] According to yet another aspect of the present invention, by improving the structure of the uncoated portion adjacent to the core of the electrode assembly, it is possible to prevent the cavity in the core of the electrode assembly from being blocked when the uncoated portion is bent, thereby facilitating the electrolyte injection process and the welding process of the battery can and the current collector plate.

[0468] According to yet another aspect of the present invention, it is possible to provide a cylindrical battery cell having a structure in which internal resistance is low, internal short circuits are prevented, and welding strength between a current collector plate and an uncoated portion is improved, as well as a battery pack and a vehicle including the same.

[0469] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims. [Example]

[0470] (A-1) Preparation of current collector 1) Preparation of the positive electrode current collector As shown in Table 1 below, a metal thin film (thickness 15 μm) for a current collector made of aluminum material including a plain area on which the pieces of Group 1 and Group 2 were to be formed was prepared.

[0471] The metal thin film had a length in the winding direction (B1 + B2 + B3) of 4000 mm from the core to the outer periphery, and a width in the winding axial direction of 75 mm. The metal thin film was divided into regions: B1 was the core-side uncoated region, B3 was the outer-periphery uncoated region, and B2, located between the core-side uncoated region and the outer-periphery uncoated region, was an intermediate uncoated region. The length of B1 was 350 mm, the length of B2 was 3500 mm, and the length of B3 was 150 mm.

[0472] In the width direction of the metal thin film, a predetermined width from the second side portion inward is made up of the positive electrode active material portion, and the remainder is made up of the first portion which is an uncoated portion, and the height of the core side uncoated portion and the outer periphery side uncoated portion in the winding axis direction is lower than that of the intermediate uncoated portion.

[0473] 2) Preparation of negative electrode current collector A negative electrode current collector was prepared in the same manner as the positive electrode current collector, except that a copper thin film (thickness 10 μm) was used as the current collector material and the width in the winding axis direction was 80 mm.

[0474] [Table 1]

[0475] (B-1) Preparation of current collector 1) Preparation of the positive electrode current collector As shown in Table 2 below, a metal thin film (thickness 15 μm) for a current collector made of aluminum material including a plain area on which the pieces of Group 1 were to be formed was prepared.

[0476] The metal thin film had a length in the winding direction (B1 + B2 + B3) of 4,000 mm from the core to the outer periphery, and a width in the winding axial direction of 75 mm. The metal thin film was divided into regions: B1 was the core-side plain region, B3 was the outer-periphery plain region, and B2, located between the core-side plain region and the outer-periphery plain region, was the intermediate plain region. The length of B1 was 350 mm, the length of B2 was 3,500 mm, and the length of B3 was 150 mm.

[0477] In the width direction of the metal thin film, a predetermined width from the second side portion inward is made up of the positive electrode active material portion, and the remainder is made up of the first portion which is an uncoated portion, and the height of the core side uncoated portion and the outer periphery side uncoated portion in the winding axis direction is lower than that of the intermediate uncoated portion.

[0478] 2) Preparation of negative electrode current collector A negative electrode current collector was prepared in the same manner as the positive electrode current collector, except that a copper thin film (thickness 10 μm) was used as the current collector material and the width in the winding axis direction was 80 mm.

[0479] [Table 2]

[0480] (2) Manufacturing of the negative electrode Average particle size (D 5011 μm of amorphous natural graphite, carbon black, carboxymethyl cellulose (CMC), and styrene butadiene rubber (SBR) were mixed with water in a weight ratio of 94:1.5:2:2.5 to prepare a slurry for the negative electrode active material layer, with the remaining components (excluding water) being 50 wt%. The slurry was applied to the negative electrode active material portion on the surface of the copper current collector prepared as described above using a slot die at a running speed of 40 m / min. The width of the negative electrode active material portion in the winding direction was 70 mm, and the width of the uncoated portion was 10 mm. The loading amount of the negative electrode active material was 16 mg / cm based on the electrode area. 2 The copper thin film coated with the negative electrode active material slurry was dried by passing it through a 60 m long hot air oven, and the oven temperature was controlled to maintain 130°C. Then, the target thickness was set to 180 μm and roll pressed to obtain a negative electrode with a density of 3.45 g / cc.

[0481] Thereafter, the middle plain section was notched with a laser to divide it into a plurality of pieces so as to satisfy the conditions in Table 1. At this time, the lower ends of the notch valleys of each piece were adjusted to have substantially the same height.

[0482] (3) Manufacturing of the positive electrode Li(Ni) as the positive electrode active material 0.6 Mn 0.2 Co 0.2 A slurry for the positive electrode active material was prepared by adding 02 (NCM-622), carbon black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder to water as a dispersion medium in a weight ratio of 96:2:2. The slurry was coated on the surface of the aluminum current collector prepared as described above, and the cathode was fabricated by drying and rolling under the same conditions as for the anode. The width of the positive electrode active material portion in the winding direction was 65 mm, and the width of the uncoated portion was 10 mm.

[0483] At this time, the positive electrode active material layer was set to an NP ratio of 1.18 (118%, approximately 27.7 cm ) of the battery, taking into account the theoretical discharge capacity of the NMC622. 2In order to satisfy the NP ratio, the width of the positive electrode was made narrower than that of the negative electrode, and the positive electrode was positioned within the negative electrode based on the width.

[0484] Thereafter, the middle plain section was notched with a laser to divide it into a plurality of pieces so as to satisfy the conditions in Table 1. At this time, the lower ends of the notch valleys of each piece were adjusted to have substantially the same height.

[0485] (4) Separation membrane manufacturing Approximately 5 wt% of polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP) polymer was added to tetrahydrofuran (THF) and dissolved at 50°C for approximately 12 hours to prepare a polymer solution. BaTiO powder with a particle size of approximately 400 nm was added and dispersed in the polymer solution at 20 wt% of the total solids to prepare a mixed solution (BaTiO / PVdF-HFP = 80:20 (weight ratio)). The mixed solution was coated on both sides of a polypropylene porous film using a doctor blade. After coating, the THF was dried to obtain the final organic / inorganic composite porous separator. The final separator thickness was approximately 30 μm. Measurement of the pores using a porosimeter revealed that the pore size and porosity of the final organic / inorganic composite porous separator were 0.4 μm and 60 vol%, respectively.

[0486] (5) Preparation of electrode assembly The prepared anode / separator / cathode were stacked in this order and wound up to fabricate an electrode assembly with a jelly roll structure. In Example A-1, one end of the separator in the width direction was positioned toward the outside of the electrode assembly by 30% (1.5 mm) of the height of the minimum bend segment (Group 1) based on the reference line.

[0487] In Example A-2, one widthwise end of the separator was positioned toward the outside of the electrode assembly by 10% (0.5 mm) of the height of the minimum bend segment (Group 1) based on the reference line.

[0488] In Comparative Example A-1, one widthwise end of the separator was positioned toward the outside of the electrode assembly by 50% of the height of the minimum bent piece (Group 1) based on the reference line.

[0489] Meanwhile, in Example B-1, one end of the separator in the width direction was positioned toward the outside of the electrode assembly by 10% (0.6 mm) of the height of the minimum bend segment (Group 1) based on the reference line.

[0490] In Example B-2, one end of the separator in the width direction was positioned so as to coincide with the reference line.

[0491] In Example B-3, one widthwise end of the separator was positioned toward the inside of the electrode assembly by 30% (1.8 mm) of the height of the minimum bent segment (Group 1) based on the reference line.

[0492] (6) Battery manufacturing (4680 type) The exposed upper and lower sections of Groups 1 to 7 of the electrode assembly of Example A-1 were folded toward the core, and then positive and negative current collectors were welded to the upper and lower bent surfaces, respectively. A cylindrical cell with the structure shown in FIG. 25 was then fabricated. Specifically, the electrode assembly with the welded positive and negative current collectors was inserted into a battery housing with pre-attached external terminals. The positive and negative current collectors were welded to the external terminals, and the periphery of the negative current collector was welded to the beading. The battery housing was then placed in the chamber of an electrolyte injection device and stood upright so that the opening of the battery housing was facing away from gravity. A non-aqueous electrolyte was then prepared by dissolving LiPF6 to a concentration of 1.0 M in an organic solvent mixture of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) in a 1:2:1 (volume ratio). Then, an electrolyte was injected from the opening of the battery housing, and the chamber pressure was increased to 800 kPa for 20 seconds and maintained for 150 seconds. After that, the chamber pressure was reduced to -90 kPa for 20 seconds and a substantial vacuum state was maintained for 20 seconds. After the electrolyte impregnation process was completed, the opening of the battery housing was sealed with a sealant via a gasket, completing the fabrication of a cylindrical cell.

[0493] The batteries of Example A-2, Comparative Example A-1, Example B-1, Example B-2 and Example B-3 were also fabricated by applying the above-mentioned manufacturing process in substantially the same manner.

[0494] (7) Evaluation of electrolyte impregnation amount The batteries of Example A-1, Example A-2, Comparative Example A-1, Example B-1, Example B-2, and Example B-3 were disassembled to obtain the positive and negative electrodes. Then, the negative and positive electrodes were cut into 10 cm pieces at a total of 9 locations. 2100 samples were cut out. The nine samples were obtained by cutting out the nine samples: three from the area adjacent to the core of the electrode assembly (#1 to #3), three from the area adjacent to the outer periphery of the electrode assembly (#7 to #9), and three from the central area of ​​the electrode in the winding direction (#4 to #6). When three samples were obtained from each sample acquisition area, one was taken from the bottom, one from the center, and one from the top of the active material layer along the winding axis. Referring to Figure 40, samples #1, #4, and #7 were taken near one end of the electrode width direction, samples #3, #6, and #9 were taken near the other end of the electrode width direction, and samples #2, #5, and #8 were taken from the middle portion. Note that Figure 40 simply shows the sample acquisition areas based on Figure 7a. For other patterns and values ​​of the sample acquisition areas, see Tables 1 and 2 above.

[0495] 28 and 29 show the amount of electrolyte impregnated at each position on the electrode for the positive and negative electrodes according to Comparative Example A-1, for the positive and negative electrodes according to Example A-1, for the positive and negative electrodes according to Example A-1, for the positive and negative electrodes according to Example A-2, for the positive and negative electrodes according to Example A-2, for the positive and negative electrodes according to Example B-1, for the positive and negative electrodes according to Example B-2, and for the positive and negative electrodes according to Example B-3.

[0496] The amount of impregnated electrolyte was determined by the difference between the weight of the control sample and the weight of the sample. The control sample was fabricated identically to the electrodes of Examples A-1, A-2, and Comparative Example A-1, and was obtained from the same positions on the positive and negative electrodes that were not impregnated with electrolyte.

[0497] The average amount of electrolyte impregnated in each of the portions #1 to #9 was 60.3 mg for the electrode assembly of Example A-1, 59.6 mg for the electrode assembly of Example A-2, and 56.3 mg for the electrode assembly of Comparative Example A-1. It was confirmed that the amounts of electrolyte impregnated in Examples A-1 and A-2 were higher than that of Comparative Example A-1.

[0498] Furthermore, the total amount of electrolyte impregnation for the positive electrode sample and the negative electrode sample obtained from the center point (#2) of the active material portion in the winding axis direction in the sample acquisition region adjacent to the core of the electrode assembly was 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. This shows that even near the core of the electrode assembly where the amount of electrolyte impregnation is relatively small, Examples A-1 and A-2 have a larger amount of electrolyte impregnation than Comparative Example A-1.

[0499] [Table 3]

[0500] FIG. 45 is a graph showing the results of counting the number of laminations of the segmented sections along the radial direction in the folded surface region F of the positive electrode formed on the upper part of the electrode assembly according to Example A-1. Substantially the same results are observed in the electrode assembly according to Example A-2 and the examples of Group B below. The horizontal axis of the graph represents the radius based on the center of the core, and the vertical axis of the graph represents the number of laminations of the segmented sections counted at each radius point. In the electrode assembly according to the example, the uniform lamination number section is the radial section of the flat region on the graph. Outside the uniform lamination number section, there is a lamination number reduction section where the number of laminations of the segmented sections decreases as the radius increases. The lamination number reduction section b2 is a radial section where the number of laminations of the segmented sections decreases as the radius of the electrode assembly increases. The uniform lamination number section b1 and the lamination number reduction section b2 are adjacent in the radial direction and are complementary to each other.

[0501] [Table 4]

[0502] The average amount of electrolyte impregnated in each of the portions #1 to #9 was 69.6 mg for the electrode assembly of Example B-1, 70.1 mg for the electrode assembly of Example B-2, and 73.0 mg for the electrode assembly of Example B-3.

[0503] In addition, the total amount of electrolyte impregnated into the positive electrode sample and the negative electrode sample obtained from the center point (#2) of the active material part in the winding axis direction in the sample acquisition region adjacent to the core of the electrode assembly was 54.3 mg for the electrode assembly of Example B-1, 52.4 mg for the electrode assembly of Example B-2, and 53.9 mg for the electrode assembly of Example B-3.

[0504] As can be seen from the above, impregnation was advantageous when one end of the separator was positioned close to the notch valley. Furthermore, it was confirmed that overall electrolyte impregnation was improved when the separator was positioned toward the inside of the electrode assembly relative to the reference line. Therefore, as long as insulation between the positive and negative electrodes is ensured, it is possible to improve the impregnation effect by positioning the separator toward the inside of the electrode assembly relative to the reference line. [Explanation of symbols]

[0505] 10 Positive electrode plate 11 Negative electrode plate 12 Separation membrane 20 Current collector 21 Active material 22 Plain area 30 Current collector plate 31 Current collector plate 32 Plain area 40 Electrode plate 41 Current collector 42 Electrode active material section 42 Active material section 43 Plain area 44 insulating coating layer 45 Electrode plate 50 electrode plate 60, 60', 61, 61' minute sections 70 Electrode plate 80, 90, 100, 110, 120, 130 electrode assembly 140 cylindrical battery cells 141 Electrode assembly 142 Battery Can 143 Sealed body 144 First current collector plate 145 Second current collector plate 146 Insulators 147 Beading section 148 Crimping section 149 leads 150, 160, 170, 180, 190, 200, 210, 220 Cylindrical Battery Cells 151 Lead hole 152 Venting section 171 Battery Can 172 Rivet terminal 173 Second gasket 174 Insulating Cap 176 Second current collector plate 178 Sealed body 179 Vent 180 cylindrical battery cells 180 Beading section 181 Crimping section 300 battery pack 301 Cylindrical Battery Cell 302 Pack Housing

Claims

1. The fuel cell includes a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate, In the electrode assembly, the first electrode plate, the second electrode plate, and the separator are wound in one direction around an axis to form a plurality of winding turns, the first electrode plate and the second electrode plate each independently include a first side portion and a second side portion, the first side portion and the second side portion being disposed on opposite sides in the axial direction; the first electrode plate and the second electrode plate each independently include a first portion and a second portion on at least one surface, the first portion being an electrode active material portion coated with an electrode active material and extending from the second side portion toward the first side portion; the second portion is a plain portion that is not coated with an electrode active material and extends from the first side portion toward the second side portion to the electrode active material portion of the first portion; At least a portion of the uncoated portion is divided into a plurality of sections by incised grooves of a predetermined depth, the segment has a first end coincident with a first side; All or at least a portion of the segment is bent radially relative to the axis at a bending point, which is a point in the segment below the first end, The folded portion of the segment is referred to as a folded portion, For the smallest bent segment having the smallest height among the bent segments, one end of the separator in the width direction is positioned toward the outside of the electrode assembly at a height less than 50% of the height of the minimum bend segment based on a reference line, and the reference line is a straight line extending in the winding direction X to a height corresponding to a notch valley of the cut groove; When one of the first electrode plate and 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 narrower than the width of the electrode active material portion of the negative electrode plate.

2. 2. The electrode assembly according to claim 1, wherein either one end of the separator is located between a folding point of each of the segments and a boundary line between the first portion and the second portion.

3. 3. The electrode assembly according to claim 1, wherein one end of the separation film is disposed so that the notched valley of the cut groove is covered by the separation film and is not exposed.

4. 3. The electrode assembly of claim 2, wherein the bending point is a point between the first end and a reference line, and the reference line is a straight line extending in the winding direction to a height corresponding to a notched valley of the cut groove.

5. The electrode assembly according to claim 1 or 2, wherein the first electrode plate segment and the second electrode plate segment each have a different distance from the reference line to the first end along the winding direction.

6. the folded segments of adjacent winding turns are continuously overlapped in a radial direction or an opposite direction to form a surface area at an upper end or a lower end in the winding axis direction of the electrode assembly; If the shortest distance between the highest point of the surface area and the reference line is defined as the height of the surface area, The electrode assembly according to claim 1 or 2, wherein one end of the separator is located toward the first side of the electrode assembly within 90% of the height of the surface area relative to the reference line.

7. the folded segments of adjacent winding turns are continuously overlapped in a radial direction or an opposite direction to form a surface area at an upper end or a lower end in the winding axis direction of the electrode assembly; 3. The electrode assembly of claim 1, wherein the number of laminations of the segment segments at any radial position of the surface region relative to the center of the core of the electrode assembly is defined as the number of laminations of the segment segments at that radial position, the surface region including a uniform lamination number section extending from the center to the outer periphery along the radius of the core of the electrode assembly, in which the number of laminations of the segment segments is the same, and a decreasing lamination number section located outside the uniform lamination number section, in which the number of laminations of the segment segments decreases toward the outer periphery.

8. The electrode assembly of claim 7 , wherein the uniform stacking number section has 10 or more stacked segments.

9. 3. The electrode assembly of claim 1, wherein the bending point and the separator are spaced apart by 0.1 mm or more.

10. The electrode assembly according to claim 1 or 2, wherein a distance from the first end of the minimum bent segment to the reference line is 2 mm or more.

11. In the minimum bending segment, the length from the reference line to the bending line is equal to or longer than the length from the bending line to the first end; 3. The electrode assembly of claim 1, wherein the bending point is a point where a tangent to a portion of the segment bent toward a winding center by an external force begins to have an inclination of 45° or less, and the inclination of the tangent refers to an angle between a tangent to the bending point and a plane perpendicular to a winding axis of the electrode assembly.

12. In the minimum bent segment, a length from a reference line to the bent line based on the bent line is equal to or shorter than a length from the bent line to a first end of the segment; 12. The electrode assembly of claim 11, wherein the bend line includes a bend point and is horizontal to a reference line, the bend point being a point where a tangent to a portion of the electrode sheet that is bent toward a winding center due to an external force begins to have an inclination of 45° or less, and the inclination of the tangent is an angle between a tangent to the bend point and a plane perpendicular to a winding axis of the electrode assembly.

13. 3. The electrode assembly of claim 1, wherein the electrode assembly further includes a segment (segment A) having a height lower than the minimum bent segment, or does not include a segment having a height lower than the minimum bent segment, the minimum bent segment being the minimum segment, and the height of the segment means the shortest distance from a reference line to a first end of the segment.

14. The electrode assembly according to claim 13 , wherein the segment A is disposed closer to the core than the other segments among the plurality of segments.

15. The electrode assembly of claim 1 or 2, wherein the separator comprises: a porous polymer substrate; and a porous coating layer disposed on at least one side of the porous polymer substrate, the porous coating layer including inorganic particles and a binder polymer.

16. The electrode assembly of claim 15 , wherein the inorganic particles include inorganic particles having hydrophilic surfaces.

17. The fuel cell includes a first electrode plate, a second electrode plate, and a separator interposed between the first electrode plate and the second electrode plate, In the electrode assembly, the first electrode plate, the second electrode plate, and the separator are wound in one direction around an axis to form a plurality of winding turns, the first electrode plate and the second electrode plate each independently include a first side portion and a second side portion, the first side portion and the second side portion being disposed on opposite sides in the axial direction; the first electrode plate and the second electrode plate each independently include a first portion and a second portion on at least one surface, the first portion being an electrode active material portion coated with an electrode active material and extending from the second side portion toward the first side portion; the second portion is a plain portion that is not coated with an electrode active material and extends from the first side portion toward the second side portion to the electrode active material portion of the first portion; At least a portion of the plain portion is divided into a plurality of segments by incision grooves, The segment has a first end, All or at least a portion of the segment is bent radially relative to the axis at a bending point, which is a point in the segment below the first end, The folded portion of the segment is referred to as a folded portion, For the smallest bent segment having the smallest height among the bent segments, one end of the separator in the width direction is positioned toward the outside of the electrode assembly at a height less than 50% of the height of the minimum bend segment based on a reference line, and the reference line is a straight line extending in the winding direction X to a height corresponding to a notch valley of the cut groove; When one of the first electrode plate and 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 narrower than the width of the electrode active material portion of the negative electrode plate.

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