Electrode assembly, battery, and battery pack and vehicle comprising same

Abstract

The invention discloses an electrode assembly, a battery, and a battery pack and a vehicle including the same. An electrode assembly includes a first electrode, a second electrode, and a separator interposed therebetween, the first electrode, the second electrode, and the separator being wound about a winding axis such that a core and an outer periphery are defined, wherein the first electrode includes a first active material portion coated with an active material layer in the winding direction and a first uncoated portion not coated with the active material layer and exposed to the outside of the separator, the first uncoated portion including a plurality of segments that can be bent independently, the plurality of segment pieces are defined as electrode tabs bent in a radial direction of the electrode assembly, and at least a partial region of the first uncoated portion including the plurality of segment pieces may include a cutout portion extending in a direction parallel to the winding direction.

Description

Technical Field

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

[0002] This application claims priority to Korean Patent Application No. 10-2022-0088962 filed in Korea on Jul. 19, 2022, the disclosure of which is incorporated herein by reference. Background Art

[0003] Secondary batteries, which are easily applicable to various product groups and have electrical characteristics such as high energy density, are widely used not only in portable devices but also in electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by an electric drive source.

[0004] These secondary batteries have attracted attention as new energy sources that improve environmental friendliness and energy efficiency because they have a major advantage of being able to significantly reduce the use of fossil fuels and a secondary advantage of using energy without generating byproducts.

[0005] Secondary batteries widely used in the art currently include lithium-ion batteries, lithium polymer batteries, nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, etc. The unit secondary battery (i.e., unit battery) has an operating voltage of about 2.5V to 4.5V. Therefore, when a higher output voltage is required, a battery pack can be constructed by connecting a plurality of batteries in series. In addition, according to the charge / discharge capacity required for the battery pack, a plurality of batteries can be connected in parallel to form a battery pack. Therefore, the number of batteries included in the battery pack and the form of electrical connection can be set in various ways according to the required output voltage and / or charge / discharge capacity.

[0006] At this time, as a unit secondary battery, cylindrical batteries, rectangular batteries and pouch batteries are known. In the case of a cylindrical battery, a diaphragm used as an insulator is inserted between the positive and negative electrodes, and they are wound to form an electrode assembly in the form of a roll core, which is inserted into a battery case to construct a battery. The battery case is referred to as a battery can in the art. In addition, a strip electrode connector can be connected to the uncoated portion of each of the positive and negative electrodes, and the electrode connector electrically connects the electrode assembly and the electrode terminal exposed to the outside. For reference, the positive terminal is a cover of a sealing body that seals the opening of the battery case, and the negative terminal is a battery case. However, according to a conventional cylindrical battery having such a structure, since the current is concentrated in the strip electrode connector connected to the uncoated portion of the positive electrode and / or the uncoated portion of the negative electrode, the current collection efficiency is not good due to the large resistance and large heat generation.

[0007] For small cylindrical batteries of form factor 1865 (diameter: 18 mm, height: 65 mm) or form factor 2170 (diameter: 21 mm, height: 70 mm), resistance and heat are not major issues. However, when the form factor is increased to apply cylindrical batteries to electric vehicles, the cylindrical batteries may catch fire while generating a lot of heat around the electrode joints during the fast charging process.

[0008] To solve this problem, a cylindrical battery (so-called jointless cylindrical battery) is provided, in which the uncoated portion of the positive electrode and the uncoated portion of the negative electrode are designed to be located at the top and bottom of a jellyroll-type electrode assembly, respectively, and the current collector is welded to the uncoated portion to improve the current collection efficiency.

[0009] Figures 1 to 3 is a diagram showing a process of manufacturing a jointless cylindrical battery. Figure 1 shows the structure of the electrode, Figure 2 shows the process of winding the electrode, and Figure 3 The process of welding the current collector to the bent surface area of ​​the uncoated portion is shown.

[0010] Reference Figures 1 to 3 The positive electrode 10 and the negative electrode 11 have a structure in which a sheet-like current collector 20 is coated with an active material layer 21 and includes an uncoated portion 22 at one long side along a winding direction X. The long side refers to a side having a relatively long length in a direction parallel to the X-axis direction.

[0011] Through Figure 2 The positive electrode 10 and the negative electrode 11 are sequentially stacked with two sheets of separators 12 as shown, and then they are wound in one direction X to manufacture the electrode assembly A. At this time, the uncoated portions of the positive electrode 10 and the negative electrode 11 are arranged in opposite directions.

[0012] After the winding process, the uncoated portion 10a of the positive electrode 10 and the uncoated portion 11a of the negative electrode 11 are bent toward the core. Thereafter, the current collectors 30, 31 are welded and coupled to the uncoated portions 10a, 11a, respectively.

[0013] The electrode tab is not separately connected to the positive electrode uncoated portion 10a and the negative electrode uncoated portion 11a, the current collectors 30, 31 are connected to the external electrode terminals, and a current path with a large cross-sectional area is formed along the winding axis direction (see arrow) of the electrode assembly A, which has the advantage of reducing the resistance of the battery. This is because the resistance is inversely proportional to the cross-sectional area of ​​the path through which the current flows.

[0014] In the jointless cylindrical battery, in order to improve the welding characteristics between the uncoated portions 10a, 11a and the current collectors 30, 31, strong pressure must be applied to the welding area of ​​the uncoated portions 10a, 11a to bend the uncoated portions 10a, 11a as flatly as possible.

[0015] However, when the welding area of ​​the uncoated parts 10a and 11a is bent, the shapes of the uncoated parts 10a and 11a may become irregularly twisted and deformed. In this case, the deformed portion may contact the electrode of the opposite polarity, causing an internal short circuit or causing fine cracks in the uncoated parts 10a and 11a. In addition, when the uncoated parts 10a and 11a are bent, all or most of the cavities 33 in the core of the electrode assembly A are blocked as the uncoated parts 32 of the core adjacent to the electrode assembly A are bent. In this case, this causes problems during the electrolyte injection process. That is, the cavity 33 in the core of the electrode assembly A is used as a channel for injecting electrolyte. However, if the corresponding channel is blocked, it is difficult to inject the electrolyte. In addition, while the electrolyte injector is being inserted into the cavity 33, the electrolyte injector may interfere with the uncoated part 32 near the core, which may cause the uncoated part 32 to tear.

[0016] In addition, the bent portions of the uncoated portions 10a, 11a that are welded to the current collectors 30, 31 should overlap multiple layers, and there should be no empty space (gap). In this way, sufficient welding strength can be obtained, and even with the latest technology such as laser welding, it is possible to prevent the laser from penetrating into the electrode assembly A and melting the separator or active material.

[0017] Meanwhile, the conventional jointless cylindrical battery has a positive electrode uncoated portion 10a integrally formed on the upper portion of the electrode assembly A. Therefore, when the periphery of the top of the battery case is pressed inward to form the curling portion, the top edge region 34 of the electrode assembly A is pressed by the battery case. This pressing may cause local deformation of the electrode assembly A, and at this time, the separator 12 may tear, causing an internal short circuit. If a short circuit occurs inside the battery, the battery may heat up or explode.

[0018] In addition, when vibration is applied to the cylindrical battery or the electrode assembly A expands as the number of charge / discharge cycles increases, stress is concentrated at the welding area of ​​the current collectors 30, 31. Stress exceeding the threshold causes cracks in the active material layer near the uncoated portion 10a, 11a of the electrode or the uncoated portion 10a, 11a. If cracks appear in the active material layer, fragments of the active material may peel off from the electrode, causing an internal short circuit. This is because fragments of the active material pass through the separator, causing the positive and negative electrodes to contact each other in a local area.

[0019] A short circuit occurring inside a cylindrical battery may cause a serious accident such as battery explosion. Therefore, a method of preventing an internal short circuit by eliminating stress occurring at a welding region of the current collecting plates 30, 31 is urgently needed. Summary of the invention

[0020] Technical issues

[0021] The present disclosure is intended to solve the problems of the related art, and thus the present disclosure is directed to providing an electrode assembly having an improved uncoated portion structure to alleviate stress applied to the uncoated portion when the uncoated portions exposed at both ends of the electrode assembly are bent.

[0022] The present disclosure also aims to provide an electrode assembly having a structure in which when stress above a threshold value is concentrated in a region of a welded current collector, stress is released by rupture of the welded region and / or an uncoated portion adjacent thereto, thereby preventing an active material layer from being damaged.

[0023] The present disclosure also relates to providing an electrode assembly that does not clog an electrolyte injection channel even if an uncoated portion is bent.

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

[0025] The present disclosure also relates to providing an electrode assembly having improved properties of a welding area by applying a segment structure to an uncoated portion of an electrode and optimizing the size (width, height, and spacing) of each segment to substantially increase the number of segment stacking in an area as a welding target area.

[0026] The present disclosure also relates to providing an electrode assembly having improved energy density and reduced resistance by applying a structure in which a current collector is welded to a bent surface region of a wide area formed by bending a segment.

[0027] The present disclosure is also directed to providing a battery including a battery having an improved terminal design so that electrical wiring can be performed on an upper portion thereof.

[0028] The present disclosure also relates to providing a battery including an electrode assembly having an improved structure, a battery pack including the battery, and a vehicle including the battery pack.

[0029] The technical objectives to be solved by the present disclosure are not limited to the above contents, and other objectives not mentioned herein will be clearly understood by those skilled in the art from the following disclosure.

[0030] Technical Solution

[0031] In one aspect of the present disclosure, an electrode assembly is provided, comprising: a first electrode; a second electrode; and a separator, which is inserted between the first electrode and the second electrode, the first electrode, the second electrode and the separator are wound around a winding axis to define a core and a periphery of the electrode assembly, wherein the first electrode comprises a first active material portion coated with an active material layer along a winding direction and a first uncoated portion that is not coated with the active material layer and is exposed outside the separator, the first uncoated portion comprises a plurality of independently bendable segments, the plurality of segments are defined as electrode joints in a bent state along a radial direction of the electrode assembly, and at least a portion of the first uncoated portion having a plurality of segments comprises a cutout portion extending in a direction parallel to the winding direction.

[0032] Each of the plurality of segments may have a geometric shape connecting one or more straight lines, one or more curved lines, or a combination thereof.

[0033] The cutting groove is interposed between the segments adjacent in the winding direction, and the cutout portion may be provided in a region of the first uncoated portion between a bottom of the cutting groove and the first active material portion.

[0034] In a region of the first non-coating portion where the plurality of sections are provided, the cutout portion may be continuously formed in one direction parallel to a winding direction of the electrode assembly.

[0035] In the region of the first non-coating portion where the plurality of sections are provided, the cutout portion may be discontinuously formed in one direction parallel to a winding direction of the electrode assembly.

[0036] The cut portion may include a plurality of sub-cut portions discontinuously formed in a direction parallel to a winding direction of the electrode assembly, and the first uncoated portion may have a region where lengths of the sub-cut portions gradually increase or decrease in the winding direction of the electrode assembly.

[0037] The cut portion may include a plurality of sub-cut portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the first uncoated portion may have a region where an interval distance between adjacent sub-cut portions gradually increases or decreases in the winding direction of the electrode assembly.

[0038] The cutout portion may include a plurality of sub-cutout portions discontinuously formed in a direction parallel to a winding direction of the electrode assembly, and the plurality of sub-cutout portions may have substantially the same height in a winding axis direction.

[0039] The cut portion may include a plurality of sub-cut portions discontinuously formed in a direction parallel to a winding direction of the electrode assembly, and the first uncoated portion may have regions where heights of the sub-cut portions in a winding axis direction are different from each other.

[0040] The cut portion may include a plurality of sub-cut portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the first uncoated portion may have a region in which a distance between the cutting groove and the sub-cut portions gradually increases or decreases in the winding direction of the electrode assembly.

[0041] Preferably, the distance between the cutout portion and the bottom of the cutting groove may be 0.1 mm to 1.9 mm.

[0042] The cutout portion may include an array of a plurality of perforations formed along a winding direction of the electrode assembly.

[0043] The perforations may have a circular, square, diamond, triangular or oval shape.

[0044] The cutout portion may include an array of a plurality of grooves formed in a winding direction of the electrode assembly.

[0045] The grooves may have a circular, square, diamond, triangular or oval shape.

[0046] An insulating coating layer may be provided on a boundary between an area in the first active material portion and an uncoated portion where the bottom of the cutting groove and the first active material portion are spaced apart from each other, and a distance from the bottom of the cutting groove to the cut portion may be smaller than a distance from the cut portion to the insulating coating layer.

[0047] The electrode assembly according to the present disclosure may further include a current collector welded to a bent surface area formed by bending a plurality of segments in a radial direction of the electrode assembly, and at least a portion of the cutout portion may be disposed to overlap a lower area of ​​the segment welded to the current collector.

[0048] The cutout portion may not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the current collector.

[0049] In an electrode assembly according to the present disclosure, the second electrode may include a second active material portion coated with an active material layer along a winding direction and a second uncoated portion not coated with an active material layer, the second uncoated portion may include a plurality of segments that can be bent independently, the plurality of segments may be defined as electrode joints that are in a bent state along a radial direction of the electrode assembly, and at least a portion of the second uncoated portion having a plurality of segments may include a cutout portion extending in a direction parallel to the winding direction.

[0050] The electrode assembly according to the present disclosure may also include: a second current collector, which is welded to a bent surface area formed by bending multiple segments of the second uncoated portion, and a cutout portion formed in the second uncoated portion may be formed between the segment welded to the second current collector and the second active material portion.

[0051] The cutout portion formed in the second non-coating portion may not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the second current collector.

[0052] In another aspect of the present disclosure, a battery is provided, comprising: an electrode assembly comprising a first electrode, a second electrode, and a separator interposed between the first electrode and the second electrode, the first electrode, the second electrode, and the separator being wound around a winding axis to define a core and a periphery of the electrode assembly, wherein the first electrode comprises a first active material portion coated with an active material layer in a winding direction and a first uncoated portion not coated with the active material layer and exposed outside the separator, the first uncoated portion comprising a plurality of independently bendable segments, the plurality of segments being defined as electrode tabs in a bent state in a radial direction of the electrode assembly, and at least a portion of the first uncoated portion having a plurality of segments comprising a cutout portion extending in a direction parallel to the winding direction; a battery case having an open end and a bottom opposite thereto, being configured to accommodate the electrode assembly in a space between the open end and the bottom, and being electrically connected to one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal the open end of the battery case; and a terminal having a surface exposed to the outside and being electrically connected to the other of the first electrode and the second electrode to have a second polarity.

[0053] The sealing body may include a cover configured to seal the open end of the battery case, a gasket inserted between the edge of the cover and the open end of the battery case, and a pressing edge portion configured to extend and bend toward the interior of the battery case and configured to surround and fix the edge of the cover together with the gasket, and the terminal having the second polarity may be the cover.

[0054] According to the present disclosure, the battery may also include a first current collector welded to a bent surface area formed by bending multiple segments of the first uncoated portion along the radial direction of the electrode assembly, and a cutout portion formed in the first uncoated portion may be formed between the segment welded to the first current collector and the first active material portion.

[0055] The cutout portion may not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the current collector.

[0056] The terminal may be a rivet terminal insulatedly mounted in a penetration hole formed at the bottom of the battery case and electrically connected to the first current collector to have the second polarity.

[0057] The battery according to the present disclosure may further include an insulator interposed between an inner surface of the bottom of the battery case and an upper surface of the first current collector to electrically insulate the inner surface of the bottom of the battery case from the first current collector.

[0058] In a battery according to the present disclosure, the second electrode may include a second active material portion coated with an active material layer along a winding direction and a second uncoated portion not coated with the active material layer, the second electrode may have a first polarity, the second uncoated portion may include a plurality of independently bendable segments, the plurality of segments may be defined as electrode joints in a bent state along a radial direction of the electrode assembly, and at least a portion of the second uncoated portion having a plurality of segments may include a cutout portion extending in a direction parallel to the winding direction.

[0059] The battery according to the present disclosure may also include: a second current collector welded to a bent surface area formed by bending multiple segments of the second uncoated portion, and a cutout portion formed in the second uncoated portion may be formed between the segment welded to the second current collector and the second active material portion.

[0060] The cutout portion formed in the second non-coating portion does not intersect an imaginary line passing through the center of the upper side and the center of the lower side of the segment welded to the second current collector.

[0061] The battery case may include a beaded portion pressed inwardly on an inner wall adjacent to the open end, and at least a portion of an edge of the second current collector is electrically connected to the beaded portion.

[0062] The battery according to the present disclosure may further include: a cover having an edge supported by a curling portion and having no polarity; a gasket inserted between the edge of the cover and the open end of the battery case; and a pressing portion configured to extend and bend toward the inside of the open end of the battery case, and configured to surround and fix the edge of the cover together with the gasket, and at least a portion of the edge of the second current collector may be inserted and fixed between the curling portion and the gasket by the pressing portion.

[0063] At least a portion of the edge of the second current collector may be welded to the curled portion.

[0064] In yet another aspect of the present disclosure, a battery pack is provided, comprising a plurality of batteries as described above.

[0065] Preferably, the ratio of the diameter to the height of the battery may be greater than 0.4.

[0066] Preferably, the battery may have a 46110, 4875, 48110, 4880 or 4680 form factor.

[0067] Preferably, the battery may have a resistance of 4 milliohms or less.

[0068] According to one aspect, in the battery pack, a plurality of batteries may be arranged in a predetermined number of rows, and a terminal of each battery may be arranged to face an outer surface of a bottom of a battery case upward.

[0069] According to another aspect, a battery pack may include a plurality of bus bars connecting a plurality of batteries in series and in parallel.

[0070] Preferably, a plurality of bus bars may be arranged on the upper part of a plurality of batteries, and each bus bar may include a main body portion extending between the terminals of adjacent batteries, a plurality of first bus bar terminals extending in a one side direction of the main body portion and electrically connected to the terminals of the batteries located in the one side direction, and a plurality of second bus bar terminals extending in the other side direction of the main body portion and electrically connected to the outer surface of the bottom of the battery casing of the batteries located in the other side direction.

[0071] In yet another aspect of the present disclosure, a vehicle is provided, which includes a battery pack.

[0072] Beneficial Effects

[0073] According to one aspect of the present disclosure, by using the uncoated portions themselves protruding on the upper and lower portions of the electrode assembly as electrode tabs, the internal resistance of the battery may be reduced and the energy density may be increased.

[0074] According to another aspect of the present disclosure, by improving the structure of the uncoated portion of the electrode assembly so that the electrode assembly and the inner periphery of the battery case do not conflict during the process of forming the curling portion of the battery case, a short circuit inside the cylindrical battery due to local deformation of the electrode assembly can be prevented.

[0075] According to another aspect of the present disclosure, by improving the structure of the uncoated portion of the electrode assembly, the uncoated portion can be prevented from being torn when being bent, and by sufficiently increasing the number of overlapping layers of the uncoated portion, the welding strength of the current collector can be improved.

[0076] According to another aspect of the present disclosure, the characteristics of the area of ​​the welding current collector can be improved by applying a segment structure to the uncoated portion of the electrode and optimizing the size (width, height, spacing) of the segment to sufficiently increase the number of segment stacking areas serving as the welding target area.

[0077] According to another aspect of the present disclosure, an electrode assembly having the following structure can be provided: when stress higher than a threshold value is concentrated in the region of the welded current collector of the electrode assembly, stress is relieved by rupturing the welded region and / or the uncoated portion (or segment) adjacent thereto, thereby preventing the active material layer from being damaged.

[0078] According to still another aspect of the present disclosure, by applying a structure in which a current collector is welded to a wide area of ​​a bent surface area formed by bending a segment, an electrode assembly having improved energy density and reduced resistance may be provided.

[0079] According to still another aspect of the present disclosure, a cylindrical battery having an improved design enabling electrical wiring to be performed on an upper portion thereof may be provided.

[0080] According to another embodiment of the present disclosure, since the structure of the uncoated portion adjacent to the core of the electrode assembly is improved, the cavity in the core of the electrode assembly can be prevented from being blocked when the uncoated portion is bent. Therefore, the electrolyte injection process and the process of welding the battery case (or terminal) and the current collector can be easily performed.

[0081] According to still another aspect of the present disclosure, a cylindrical battery having a structure in which internal resistance is low, an internal short circuit is prevented, and welding strength between a current collector and an uncoated portion is improved, and a battery pack and a vehicle including the cylindrical battery may be provided.

[0082] Specifically, the present disclosure may provide a cylindrical battery having a diameter-to-height ratio of 0.4 or more and a resistance of 4 milliohms or less, and a battery pack and a vehicle including the cylindrical battery.

[0083] In addition, the present disclosure may have several other effects, and these effects will be described in each embodiment, or any description that can be easily inferred by those skilled in the art will be omitted for the effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure should not be construed as being limited to the accompanying drawings.

[0085] Figure 1 is a plan view showing the structure of an electrode for manufacturing a conventional tabless cylindrical battery.

[0086] Figure 2 is a diagram showing the electrode winding process of a conventional jointless cylindrical battery.

[0087] Figure 3 is a diagram showing a process of welding a current collector to a bent surface area of ​​an uncoated portion in a conventional jointless cylindrical battery.

[0088] Figure 4 is a plan view showing the structure of an electrode according to the first embodiment of the present disclosure.

[0089] Figure 5 is a plan view showing the structure of an electrode according to a second embodiment of the present disclosure.

[0090] Figure 6 is a plan view showing the structure of an electrode according to a third embodiment of the present disclosure.

[0091] Figure 7a is a plan view showing the structure of an electrode according to a fourth embodiment of the present disclosure.

[0092] Figure 7b is a diagram showing the definition of the width, height, and pitch of segments according to an embodiment of the present disclosure.

[0093] Figure 7c is a diagram illustrating an arc formed by a lower end portion of a segment defining a segment width relative to the center of a core of an electrode assembly when an electrode is wound according to an embodiment of the present disclosure.

[0094] Figure 7d is a schematic diagram showing the height h of the segment where the segment begins to appear according to an embodiment of the present disclosure. 1 、h 2 、h 3 、h 4 , core radius r c and the radius r of the winding turn 1 、r 2 、r 3 、r 4 A diagram of the relationship between .

[0095] Figure 7e It is used to determine the maximum value (h) of the height (H) of the segment in the segment height variable area. max ) concept map.

[0096] Figure 7f It is a schematic diagram for explaining the formula for determining the lower angle (θ) of a segment.

[0097] Figure 7g is a plan view showing a modified structure of an electrode according to the fourth embodiment of the present disclosure.

[0098] Figure 7h is a top plan view showing individual regions in which a plurality of segments may be located when an electrode according to a variation of the present disclosure is wound into an electrode assembly.

[0099] Figure 7i : is a plan view showing a first example of forming a cutout portion in an uncoated portion of an electrode according to a fourth embodiment of the present disclosure.

[0100] Figure 7j : is a plan view showing a second example of forming a cutout portion in the uncoated portion of the electrode according to the fourth embodiment of the present disclosure.

[0101] Figure 7k : is a plan view showing a third example of forming a cutout portion in the uncoated portion of the electrode according to the fourth embodiment of the present disclosure.

[0102] Figure 7l : is a plan view showing a fourth example of forming a cutout portion in the uncoated portion of the electrode according to the fourth embodiment of the present disclosure.

[0103] Figure 7m : is a plan view showing a fifth example of forming a cutout portion in the uncoated portion of the electrode according to the fourth embodiment of the present disclosure.

[0104] Figure 7n : is a plan view showing a sixth example of forming a cutout portion in the uncoated portion of the electrode according to the fourth embodiment of the present disclosure.

[0105] Figure 8a is a plan view showing the structure of an electrode according to a fifth embodiment of the present disclosure.

[0106] Figure 8b is a diagram showing the definition of the width, height, and pitch of segments according to the present disclosure and another embodiment.

[0107] Figure 8c is a plan view showing a modified structure of the electrode according to the present disclosure and the fifth embodiment.

[0108] Fig. 9 are diagrams showing segment structures according to various modifications of the present disclosure.

[0109] Fig.10a is a schematic diagram showing a cross section of a bent surface area formed by bending a segment toward a core of an electrode assembly.

[0110] Fig.10b is a top perspective view schematically illustrating an electrode assembly formed with a bent surface area.

[0111] Fig.10c is a graph showing the result of counting the number of segment laminations in the radial direction in the bent surface region of the positive electrode formed at the upper portion of the electrode assemblies according to Embodiments 1-1 to 1-7 and the comparative example.

[0112] Fig.10d is a diagram showing the results of counting the number of segment stackings along the radial direction in the bent surface area of ​​the positive electrode formed at the upper portion of the electrode assembly according to Embodiments 2-1 to 2-5, Embodiments 3-1 to 3-4, Embodiments 4-1 to 4-3, and Embodiments 5-1 to 5-2.

[0113] Fig.10e is a diagram showing the result of counting the number of segment stackings measured in the radial direction in the bent surface region of the positive electrode formed at the upper portion of the electrode assemblies according to Embodiments 6-1 to 6-6 and Embodiments 7-1 to 7-6.

[0114] Fig.10f is a top plan view of an electrode assembly showing a stacking number uniform region b1 and a stacking number reduced region b2 in a bent surface region of a segment according to an embodiment of the present disclosure.

[0115] Fig.11 This is a cross-sectional view of a jellyroll-type electrode assembly in which the electrode of the first embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode), taken along the Y-axis direction (winding axis direction).

[0116] Fig.12 : is a cross-sectional view of a jellyroll-type electrode assembly in which the electrode of the second embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode), extracted along the Y-axis direction (winding axis direction).

[0117] Fig.13 It is a cross-sectional view of a jellyroll type electrode assembly in which any one of the electrodes of the third to fifth embodiments (modifications thereof) is applied to a first electrode (positive electrode) and a second electrode (negative electrode), extracted along the Y-axis direction (winding axis direction).

[0118] Fig.14 is a cross-sectional view of an electrode assembly according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

[0119] Fig.15 is a cross-sectional view of an electrode assembly according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

[0120] Fig.16 is a cross-sectional view of an electrode assembly according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

[0121] Fig.17 is a cross-sectional view showing a cylindrical battery according to an embodiment of the present disclosure extracted along the Y-axis direction.

[0122] Fig.18 is a cross-sectional view showing a cylindrical battery according to another embodiment of the present disclosure extracted along the Y-axis direction.

[0123] Fig.19 is a cross-sectional view of a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0124] Fig. 20 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0125] Fig.21is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0126] Fig. 22 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0127] Fig.23 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0128] Fig.24 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0129] Fig.25 is a cross-sectional view showing a cylindrical battery according to still another embodiment of the present disclosure extracted along the Y-axis direction.

[0130] Fig.26 is a top plan view showing the structure of a first current collector according to an embodiment of the present disclosure.

[0131] Fig. 27 is a top plan view showing the structure of a second current collector according to an embodiment of the present disclosure.

[0132] Fig.28 is a top plan view showing a state in which a plurality of cylindrical batteries are electrically connected according to an embodiment of the present disclosure.

[0133] Fig.29 yes Fig.28 A partial enlarged view of .

[0134] Fig.30 is a diagram schematically showing a battery pack according to an embodiment of the present disclosure.

[0135] Fig.31 is a diagram schematically showing a vehicle including a battery pack according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0136] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description is made, it should be understood that the terms used in the specification and the appended claims should not be interpreted as limited to the general meaning and dictionary meaning, but are interpreted based on the meaning and concept corresponding to the technical aspects of the present disclosure on the basis of the principle that the inventor is allowed to appropriately define the terms to obtain the best interpretation.

[0137] Therefore, the descriptions presented herein are only preferred examples for illustrative purposes only and are not intended to limit the scope of the present disclosure, and it should be appreciated that other equivalents and modifications may be made thereto without departing from the scope of the present disclosure.

[0138] In addition, to assist in understanding the present disclosure, the drawings are not drawn to scale, and the sizes of some components may be exaggerated. In addition, in different embodiments, the same reference numerals may refer to the same components.

[0139] Reference to two objects of comparison being "the same" means that they are "substantially the same." Thus, the term "substantially the same" can include deviations that are considered low in the art, such as deviations of less than 5%. In addition, a parameter being consistent in a region can mean that the parameter is consistent in terms of average in the corresponding region.

[0140] Although the terms first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are used to distinguish one element from another element, and unless otherwise specified, the first element may be the second element.

[0141] Throughout the specification, unless otherwise specified, each element may be in the singular or in the plural.

[0142] When an element is “on (or under)” or “over (or under)” another element, the element may be located on the upper surface (or lower surface) of the other element, and intervening elements may be present between the element and the other element above (or under) the element.

[0143] In addition, when an element is referred to as being “connected,” “coupled” or “linked” to another element, the element may be directly connected or coupled to the other element, but it should be understood that there may be intervening elements between each element, or each element may be “connected,” “coupled” or “linked” to each other through another element.

[0144] Throughout the specification, unless expressly stated otherwise, “A and / or B” means A or B, or both A and B, and “C to D” means C or greater and D or less.

[0145] For ease of description, the direction along the length direction of the winding axis of the electrode assembly wound into a roll shape is referred to herein as the axis direction Y. Additionally, the direction around the winding axis is referred to herein as the circumferential or peripheral direction X. Additionally, the direction approaching or away from the winding axis is referred to as the radial direction. Specifically, the direction approaching the winding axis is referred to as the centripetal direction, and the direction away from the winding axis is referred to as the centrifugal direction.

[0146] First, an electrode assembly according to an embodiment of the present disclosure is described. The electrode assembly may be a jellyroll-type electrode assembly having a structure in which first and second electrodes having sheet shapes are wound in one direction with a separator interposed therebetween. However, the present disclosure is not limited by the type of electrode assembly.

[0147] Preferably, at least one of the first electrode and the second electrode includes an uncoated portion on which the active material is not coated at the end of the long side in the winding direction. At least a portion of the uncoated portion itself serves as an electrode tab. The uncoated portion includes a core-side uncoated portion adjacent to the core of the electrode assembly, a peripheral-side uncoated portion adjacent to the periphery of the electrode assembly, and an intermediate uncoated portion sandwiched between the core-side uncoated portion and the peripheral-side uncoated portion.

[0148] Preferably, at least one of the core-side uncoated portion and the outer circumference-side uncoated portion has a relatively lower height than the middle uncoated portion.

[0149] Figure 4 : is a plan view showing the structure of the electrode 40 according to the first embodiment of the present disclosure.

[0150] Reference Figure 4 , the electrode 40 of the first embodiment includes a current collector 41 made of metal foil and an active material layer 42. The metal foil may be a conductive metal such as aluminum or copper, and is appropriately selected according to the polarity of the electrode 40. The active material layer 42 is formed on at least one surface of the current collector 41. The active material layer 42 is formed along the winding direction X. The electrode 40 includes an uncoated portion 43 at the end of the long side in the winding direction X. The uncoated portion 43 is a local area of ​​the current collector 41 where the active material is not coated. The area in the current collector 41 where the active material layer 42 is formed may be referred to as an active material portion.

[0151] In the electrode 40, the width of the active material portion in the short side direction of the current collector 41 may be 50 mm to 120 mm, and the length of the active material portion in the long side direction of the current collector 41 may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion may be 1.0% to 4.0%.

[0152] Preferably, in the electrode 40, the width of the active material portion in the short side direction of the current collector 41 may be 60 mm to 70 mm, and the length of the active material portion in the long side direction of the current collector 41 may be 3 m to 5 m. Therefore, the ratio of the short side to the long side of the active material portion may be 1.2% to 2.3%.

[0153] The ratio of the short side to the long side of the active material portion is significantly less than 6% to 11%, which is the ratio of the short side to the long side of the active material portion of an electrode used in a cylindrical battery with a form factor of 1865 or 2170.

[0154] Preferably, the current collector 41 may have an elongation of 1.5% to 3.0% and a strength of 25 kgf / mm. 2 Up to 35kgf / mm 2 The elongation and tensile strength can be measured according to the measurement method of IPC-TM-650. The electrode 40 is manufactured by forming the active material layer 42 on the current collector 41 and then compressing it. When compressed, the area of ​​the uncoated portion 43 and the area of ​​the active material layer 42 have different elongations. Therefore, expansion is formed on the electrode 40 after compression, and as the electrode 40 is longer, the expansion is more severe.

[0155] The elongation and tensile strength of the current collector 41 are optimized to reduce the bending length after compression, and the warping length after compression is reduced to less than 20 mm when the length of the electrode 40 is about 4 m. The warping length is the maximum deviation of the electrode 40 in the winding direction X when the expanded electrode 20 is unfolded. The maximum deviation can be measured at the end of the outer circumference. Since the electrode 40 in which the elongation and tensile strength of the current collector 41 are optimized has a small warping length, no meandering defect occurs during the cutting operation of the uncoated portion 43 or the winding process of the electrode 40.

[0156] The smaller the elongation, the more likely the current collector 41 is to break. When the elongation of the current collector 41 is less than 1.5%, the efficiency of the rolling process of the current collector 41 is reduced, so that a break may occur in the current collector 41 when the electrode 40 coated with the active material layer 42 is pressed against the current collector 41. In addition, when the elongation of the current collector 41 exceeds 3.0%, as the elongation of the active material portion of the electrode 40 increases, the warping length increases significantly. If the tensile strength of the current collector 41 is less than 25kgf / mm 2 Or greater than 35kgf / mm 2 , the electrode process efficiency of the electrode 40 deteriorates.

[0157] The warping phenomenon is particularly problematic for positive electrode current collectors made of aluminum foil. According to the present disclosure, by using an aluminum foil having an elongation of 1.5% to 3.0% and a tensile strength of 25 kgf / mm 2 Up to 35kgf / mm 2 The use of aluminum foil as a current collector can suppress the warping phenomenon. It is desirable to form an active material layer on the current collector and use it as a positive electrode.

[0158] Preferably, the insulating coating layer 44 may be formed at the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 is formed so that at least a portion thereof overlaps the boundary between the active material layer 42 and the uncoated portion 43. The insulating coating layer 44 prevents a short circuit between two electrodes having different polarities and facing each other with a separator interposed therebetween. The insulating coating layer 44 may cover the boundary between the active material layer 42 and the uncoated portion 43 with a width of 0.3 mm to 5 mm. The width of the insulating coating layer 44 may vary along the winding direction of the electrode 40. The insulating coating layer 44 may include a polymer resin and a dielectric such as Al 2 O 3 Since the portion of the current collector 41 covered by the insulating coating layer 44 is not a region coated with an active material layer, it can be regarded as an uncoated portion.

[0159] The uncoated portion 43 includes a core-side uncoated portion B1 adjacent to the core of the electrode assembly, a peripheral-side uncoated portion B3 adjacent to the periphery of the electrode assembly, and an intermediate uncoated portion B2 interposed between the core-side uncoated portion B1 and the peripheral-side uncoated portion B3.

[0160] When the electrode 40 is wound into a core-wound electrode assembly, the core-side uncoated portion B1, the peripheral-side uncoated portion B3, and the middle uncoated portion B3 can be respectively defined as the uncoated portion in the area adjacent to the core, the uncoated portion in the area adjacent to the periphery, and the uncoated portion in the remaining area except the above-mentioned areas.

[0161] Hereinafter, the core-side uncoated portion B1 , the outer circumference-side uncoated portion B3 , and the middle uncoated portion B2 are referred to as a first portion B1 , a second portion B3 , and a third portion B2 , respectively.

[0162] In one example, the first portion B1 may be an uncoated portion of an electrode region including an innermost winding turn, and the second portion may be an uncoated portion of an electrode region including an outermost winding turn.The winding turns may be counted based on the core-side end of the electrode assembly.

[0163] In another example, the boundary of B1 / B2 can be appropriately defined as a point where the height (or variation pattern) of the uncoated portion changes significantly in proceeding from the core toward the periphery of the electrode assembly, or a point based on a predetermined % of the radius of the electrode assembly (e.g., the 5% point, 10% point, 15% point, etc. of the radius).

[0164] The boundary of B2 / B3 may be defined as a point where the height (or variation pattern) of the uncoated portion significantly changes as it progresses from the periphery of the electrode assembly toward the core, or a point based on a predetermined % of the radius of the electrode assembly (e.g., 85% point, 90% point, 95% point, etc. of the radius). When the boundary of B1 / B2 and the boundary of B2 / B3 are specified, the third portion B2 may be automatically specified.

[0165] If only the boundary of B1 / B2 is specified, the boundary of B2 / B3 can be appropriately selected at a point near the periphery of the electrode assembly. In one example, the second portion can be defined as the uncoated portion of the region of the electrode constituting the outermost winding turns. Conversely, when only the boundary of B2 / B3 is specified, the boundary of B1 / B2 can be appropriately selected at a point near the core of the electrode assembly. In one example, the first portion can be defined as the uncoated portion of the region of the electrode constituting the innermost winding turns.

[0166] It is not excluded that another structure is inserted between the first part B1 and the third part B2. In addition, it is not excluded that another structure is inserted between the third part B2 and the second part B3.

[0167] In the first embodiment, the height of the uncoated portion 43 is not constant, and there is a relative difference in the winding direction X. That is, the height of the second portion B3 (the length in the Y-axis direction) is above 0, but is relatively smaller than the heights of the first portion B1 and the third portion B2. Here, the height of each portion may be an average height or a maximum height, and the same applies to the following. In the winding direction, the third portion B2 is longer than the first portion B1 and the second portion B3.

[0168] Figure 5 : is a plan view showing the structure of an electrode 45 according to a second embodiment of the present disclosure.

[0169] Reference Figure 5 , except that the height of the second portion B3 gradually decreases toward the periphery, the electrode 45 of the second embodiment is substantially the same as that of the first embodiment.

[0170] In a modification, the second portion B3 may be deformed into a step shape with a height gradually decreasing (see the dotted line).

[0171] Figure 6 : is a plan view showing the structure of an electrode 50 according to a third embodiment of the present disclosure.

[0172] Reference Figure 6 In the electrode 50 of the third embodiment, the heights of the first portion B1 and the second portion B3 are greater than 0, but are relatively smaller than the third portion B2. In addition, the heights of the first portion B1 and the second portion B3 may be the same or different.

[0173] Preferably, the height of the third portion B2 may have a stepped shape gradually increasing from the core toward the periphery.

[0174] Patterns 1 to 7 classify the third portion B2 based on the position of the height change of the uncoated portion 43. 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 may be adjusted to disperse stress as much as possible during bending of the uncoated portion 43. Dispersing stress is to prevent the uncoated portion 43 from tearing when the uncoated portion 43 is bent toward the core of the electrode assembly.

[0175] The width (d B1 ). The core refers to the cavity existing in the winding center of the electrode assembly.

[0176] In one example, the width (d B1 ) can be increased in proportion to the bend length of pattern 1. The bend length corresponds to the pattern height based on the bend point of the pattern.

[0177] Preferably, the width (d B1 ) can be set so that the radial width of the winding turn formed by the first portion B1 is equal to or greater than the bending length of the pattern 1. In a variation, the width (d B1 ) may be set such that a value obtained by subtracting a radial width of a winding turn formed by the first portion B1 from a bending length of the pattern 1 is less than 0 or less than 10% of the core radius.

[0178] In a specific example, when the electrode 60 is used to manufacture an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d B1 ) can be set to 180mm to 350mm depending on the diameter of the core of the electrode assembly and the bending length of pattern 1.

[0179] In one embodiment, the width of each pattern may be designed to constitute one winding turn or more winding turns of the electrode assembly.

[0180] In a modification, the height of the third portion B2 may have a stepped shape in which the height increases from the core toward the periphery and then decreases.

[0181] In another modification, the second portion B3 may be modified to have the same structure as the second embodiment.

[0182] In yet another variation, the pattern structure applied to the third portion B2 may extend to the second portion B3 (see dashed line).

[0183] Figure 7a : is a plan view showing the structure of an electrode 60 according to a fourth embodiment of the present disclosure.

[0184] Reference Figure 7a In the electrode 60 of the fourth embodiment, the first portion B1 and the second portion B3 have a height of 0 or more in the winding axis direction Y, but are relatively smaller than the third portion B2. In addition, the heights of the first portion B1 and the second portion B3 in the winding axis direction Y may be the same or different.

[0185] Preferably, at least a local area of ​​the third part B2 may include a plurality of sections 61. The height of the plurality of sections 61 may be gradually increased from the core toward the periphery. The plurality of sections 61 have a geometric shape in which the width decreases from bottom to top. Preferably, the geometric figure is a trapezoid. As will be described later, the shape of the geometric figure may be modified in various ways.

[0186] The segments 61 may be formed by laser cutting. The segments 61 may be formed by known metal foil cutting processes such as ultrasonic cutting or punching.

[0187] In the fourth embodiment, in order to prevent the active material layer 42 and / or the insulating coating layer 44 from being damaged during the bending of the uncoated portion 43, it is preferred that the bottom of the cutting groove between the segments 61 ( Figure 7bA predetermined gap is provided between the electrode 60 and the active material layer 42. This is because when the uncoated portion 43 is bent, the stress is concentrated near the bottom of the cutting groove 63. The gap can vary along the winding direction of the electrode 60. The gap is 0.2mm to 4mm, preferably 1.5mm to 2.5mm. If the gap is adjusted to the corresponding numerical range, the application generated during the bending of the uncoated portion 43 can be prevented from damaging the active material layer 42 and / or the insulating coating layer 44 near the bottom of the cutting groove 63. The gap can prevent the active material layer 42 and / or the insulating coating layer 44 from being damaged due to tolerance during the cut or cutting of the segment 61. In a direction parallel to the winding direction, the gap can be substantially the same or can vary. In the latter case, the gaps of multiple segments can vary individually, in a group unit, or in two or more group units along a direction parallel to the winding direction. The bottom of the cutting groove 63 and the insulating coating layer 44 can be spaced 0.5mm to 2.0mm apart. In a direction parallel to the winding direction, the spacing distance between the lower end of the cutting groove 63 and the insulating coating layer 44 can be substantially the same or variable. In the latter case, the spacing distance of multiple sections can be changed individually, in a group of units, or in two or more group units along a direction parallel to the winding direction. When winding the electrode 60, the end of the insulating coating layer 44 in the winding axis direction Y can be located in the range of -2mm to 2mm based on the end of the diaphragm along the winding axis direction. The insulating coating layer 44 can prevent short circuits between two electrodes with different polarities and facing each other and the diaphragm inserted between them, and can support the bending point when the section 61 is bent. In order to improve the short circuit prevention effect between the two electrodes, the insulating coating layer 44 can be exposed to the outside of the diaphragm. In addition, in order to further maximize the effect of preventing short circuits between the two electrodes, the width of the insulating coating layer 44 can be increased so that the end of the insulating coating layer 44 in the winding axis direction Y is located above the lower end of the cutting groove 63. In one embodiment, the end of the insulating coating layer 44 in the winding axis direction may be located within a range of -2 mm to +2 mm based on the lower end of the cutting groove 63. The thickness of the insulating coating layer 44 may be smaller than that of the active material layer 42. In this case, there may be a gap between the surface of the insulating coating layer 44 and the separator.

[0188] In one aspect, the plurality of segments 61 may form a plurality of segment groups from the core to the periphery. At least one of the width, height and spacing of the segments belonging to the same segment group may be substantially the same. Preferably, the width, height and spacing of the segments belonging to the same segment group may be substantially the same.

[0189] Preferably, the width, height and spacing of the segments belonging to the same segment group may be substantially the same.

[0190] On the other hand, the intervals of the plurality of segments may gradually or stepwise increase from the core toward the periphery in one group unit, or in two or more group units, or vice versa.

[0191] In yet another aspect, in one group unit or in two or more group units, the intervals of the plurality of segments may gradually or stepwise increase from the core toward the periphery and then gradually or stepwise decrease, or vice versa.

[0192] In yet another aspect, in a plurality of sections, the gap between the lower end of the cutting groove 63 and the insulating coating layer 44 or the active material layer 42 may gradually or gradually increase from the core toward the periphery, or vice versa.

[0193] In yet another aspect, in a plurality of sections, the gap between the lower end of the cutting groove 63 and the insulating coating layer 44 or the active material layer 42 may gradually or stepwise increase from the core toward the periphery and then gradually or stepwise decrease, or vice versa.

[0194] Figure 7b is a diagram showing the definition of the width D, height H, and pitch P of the trapezoidal section 61 according to an embodiment of the present disclosure.

[0195] Reference Figure 7b The width (D), height (H) and spacing (P) of section 61 are designed to prevent the uncoated portion 43 near the bending point from being torn during bending of the uncoated portion 43 and to prevent abnormal deformation of the uncoated portion 43, while sufficiently increasing the number of overlapping layers of the uncoated portion 43 to ensure sufficient welding strength.

[0196] The segment 61 is bent at a line G passing through the bottom or the top of the cutting groove 63. The cutting groove 63 enables the segment 61 to be bent smoothly and easily in the radial direction of the electrode assembly.

[0197] The width (D) of the segment 61 is defined as the length between two points where two straight lines extending from the two sides 63b of the segment 61 intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height (H) of the segment 61 is defined as the shortest distance between the uppermost edge of the segment 61 and a straight line extending from the bottom 63a of the cutting groove 63. The pitch (P) of the segment 61 is defined as the length between two points where a straight line extending from the bottom 63a of the cutting groove 63 intersects with a straight line extending from the two sides 63b connected to the bottom 63a. When the side 63b and / or the bottom 63a are curved, a tangent line extending from the side 63b and / or the bottom 63a at the intersection where the side 63b and the bottom 63a intersect may be used instead of a straight line.

[0198] Preferably, the width (D) of the segment 61 is 1 mm or more. If D is less than 1 mm, when the segment 61 is bent toward the core, a region or empty space (gap) where the segment 61 does not overlap enough to sufficiently ensure sufficient welding strength may occur.

[0199] Preferably, the width (D) of the segment 61 can be adaptively adjusted according to the radius of the winding turn where the segment 61 is located, so that when the segment 61 is bent toward the core of the electrode assembly, the segment 61 overlaps well in the radial direction.

[0200] Figure 7c 1 is a diagram showing that when the electrode 60 is wound according to an embodiment of the present disclosure, the lower end portion ( Figure 1 Line D ab ) formed by the arc (A 1 A 2 )’s picture.

[0201] Reference Figure 7c , arc (A 1 A 2 ) has a length corresponding to the width (D) of the segment 61 and has a circumferential angle (Φ) based on the center of the core of the electrode assembly. The circumferential angle (Φ) can be defined as the angle between the electrode 1 and the electrode 2 at a perpendicular angle to the arc (A). 1 A 2 ) on the plane of the winding axis connecting the arc (A 1 A 2 ) is the angle between the two line segments at both ends and the center O of the core.

[0202] When the arc (A 1 A 2 ) are the same length, the circumferential angle (Φ) decreases as the radius (r) of the winding turn in which the segment 61 is located increases. Conversely, when the circumferential angle (Φ) of the segment 61 is the same, the arc (A 1 A 2 ) increases proportionally with the radius (r) of the winding turn in which the segment 61 is located.

[0203] The circumferential angle (Φ) affects the bending quality of the segment 61. In the drawings, the solid arrows indicate the direction of the force applied by the bent segment 61, and the dashed arrows indicate the direction in which the segment 61 is bent. The bending direction is the direction toward the center O of the core.

[0204] In order to improve bending uniformity and prevent cracks, the circumferential angle (Φ) of the segment 61 may be 45 degrees or less, preferably 30 degrees or less, depending on the radius (r) of the winding turn where the segment 61 is located.

[0205] In one aspect, the circumferential angle (Φ) of segment 61 may gradually or stepwise increase or decrease in the radial direction of the electrode assembly within the above numerical range. On the other hand, the circumferential angle (Φ) of segment 61 may gradually or stepwise increase or gradually or stepwise decrease in the radial direction of the electrode assembly within the above numerical range, or vice versa. On the other hand, within the above numerical range, the circumferential angle (Φ) of segment 61 may be substantially the same along the radial direction of the electrode assembly.

[0206] According to experiments, when the circumferential angle (Φ) of the segment 61 exceeds 45 degrees, the bending shape of the segment 61 is not uniform. The difference between the force applied to the middle of the segment 61 and the force applied to the side increases, so the compression of the segment 61 is not uniform in the circumferential direction. In addition, if the pressure is increased for uniformity of bending, cracks may occur in the uncoated portion 43 near the cutting groove 63.

[0207] In one embodiment, the circumferential angles (Φ) of the segments 61 included in the electrode 60 are substantially the same, and the width of the segments 61 can increase proportionally with the increase in the radius (r) of the winding turn where the segments 61 are located. The term "substantially the same" means completely the same or with a deviation of less than 5%.

[0208] For example, when the radius of the electrode assembly is 22 mm and the radius of the core is 4 mm, the segment 61 is set from the winding turn at a point where the radius is 7 mm, if the circumferential angle (Φ) of the segment 61 is uniformly 28.6 degrees, and the width (D) of the segment 61 can be increased proportionally according to the radius (r) of the winding turn where the segment 61 is located, as shown in the following Table 1. That is, whenever the radius (r) of the winding turn increases by 1 mm, the width of the segment 61 can increase by 0.5 mm at substantially the same rate.

[0209] [Table 1]

[0210]

[0211] Preferably, the width D(r) of the segment 61 located in a winding turn having a radius r based on the core center O of the electrode assembly may be determined within a range satisfying the following Formula 1.

[0212] <Formula 1>

[0213] 1≤D(r)≤(2*π*r / 360°)*45°

[0214] Preferably, based on the core center of the electrode assembly, the width D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase with an increase in the radius r of the winding turn where the segment 61 is located, or vice versa.

[0215] On the other hand, based on the core center of the electrode assembly, the width D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase within a range of 1 mm to 11 mm as the radius r of the winding turn in which the segments 61 are located increases, or vice versa.

[0216] On the other hand, based on the core center of the electrode assembly, the width D(r) of the plurality of segments 61 in the winding direction may gradually or stepwise increase as the radius r of the winding turn in which the segments 61 are located increases, and then gradually or stepwise decrease, or vice versa.

[0217] On the other hand, based on the core center of the electrode assembly, the width D(r) of multiple segments 61 in the winding direction can gradually or stepwise increase in the range of 1 mm to 11 mm as the radius r of the winding turn in which the segment 61 is located increases, and then gradually or stepwise decrease, or vice versa.

[0218] In yet another aspect, the rate at which the width D(r) of the segment 61 changes with increasing radius r of the winding turn in which the segment 61 is located can be the same or different.

[0219] In yet another aspect, the rate at which the width D(r) of the segment 61 changes with increasing radius r of the winding turn in which the segment 61 is located can be the same or different within the range of 1 mm to 11 mm.

[0220] Refer again Figure 7b , the height (H) of the segment 61 may be 2 mm or more. If the height (H) is less than 2 mm, when the segment 61 is bent toward the core, there may be areas or empty spaces (gaps) where the segments 61 do not overlap enough to fully ensure sufficient welding strength.

[0221] The height (H) of the segment 61 can be determined by applying the condition that the segment 61 does not block the core when bending toward the core. Preferably, the height (H) of the segment 61 can be adjusted so that more than 90% of the core diameter can be opened to the outside.

[0222] Preferably, the height (H) of the segment 61 may increase from the core toward the periphery, depending on the radius of the winding turn where the segment 61 is located and the radius of the core.

[0223] In one embodiment, when the height (H) of the segment 61 increases from h to h as the radius of the winding turns increases, 1 to h N When increasing in N steps, assuming that the kth height (k is a natural number from 1 to N) of the segment 61 is h k , including the height h k The starting radius of the winding turns of section 61 is r k , and the radius of the core is rc , then the height h of section 61 1 to h N It can be determined that the following formula 2 is satisfied.

[0224] <Formula 2>

[0225] 2mm≤h k ≤r k -α*r c (Preferably, α is 0.90 to 1)

[0226] If the height of segment 61 (h k ) satisfies Formula 2, then even if the segment 61 is bent toward the core, more than 90% of the core diameter can be opened to the outside.

[0227] In one example, the radius of the entire winding turn of the electrode 60 is 22 mm, the height of the segment 61 starts from 3 mm, and whenever the radius of the winding turn including the segment 61 increases by 1 mm, the height of the segment 61 increases to 3 mm, 4 mm, 5 mm and 6 mm in sequence, and the height can be kept substantially the same at 6 mm in the remaining winding turns. That is, in the radius of the entire winding turn, the radial width of the variable height region of the segment 61 is 3 mm, and the remaining radial region corresponds to the uniform height region.

[0228] In this case, when α is 1 and the equal sign condition is applied in the right inequality, according to the core radius (r c ), including the starting radius r of the winding turns of the sections 61 with heights of 3 mm, 4 mm, 5 mm and 6 mm 1 、r 2 、r 3 、r 4 This can be shown in Table 2 below.

[0229] [Table 2]

[0230]

[0231] When the segment 61 is arranged at the radial position shown in Table 2, even if the segment 61 is bent toward the core, the core is not blocked by the segment 61. 1 、r 2 、r 3 、r 4 The value of α can be shifted toward the core. In one example, when α is 0.90, r 1 、r 2 、r 3 、r 4It is possible to offset 10% of the core radius towards the core. In this case, when the segment 61 is bent towards the core, 10% of the core radius is blocked by the segment 61. The r shown in Table 1 1 、r 2 、r 3 、r 4 is the limit value of the position where the segment 61 starts. Therefore, the position of the segment 61 may be shifted toward the periphery by a predetermined distance instead of the radius shown in Table 2.

[0232] Figure 7d is a schematic diagram showing the height h of the segment 61 1 、h 2 、h 3 、h 4 , core radius (r c ) and the radius r of the winding turn at which section 61 begins 1 、r 2 、r 3 、r 4 Graph of the relationship.

[0233] Refer to Table 2 and Figure 7d For example, when the core radius (r c ) is 3m, including the height of 3mm (h 1 )、4mm(h 2 )、5mm(h 3 ) and 6mm(h 4 ) of the winding turns of the section 61 1 、r 2 、r 3 and r 4 The height of the section 61 can be 6mm, 7mm, 8mm and 9mm respectively, and from the radius 9mm to the last winding turn, the height of the section 61 can be maintained at 6mm. 1 ) may not include the segment 61. In this example, since the winding turn with a radius of 6 mm is located closest to the core C with a height of 3 mm (h 1 ) of the segment 61, so even if the segment 61 is bent toward the core C, the segment 61 only covers a radial area of ​​3 mm to 6 mm and does not substantially block the core C. According to the α value of formula 2, the position of the segment 61 can be within the core radius (r c ) within 10% of the core C.

[0234] In another embodiment, based on the core center of the electrode assembly, the height of the segment 61 may increase at the same or different rates as the starting radius r of the winding turn where the segment 61 is located increases.

[0235] Preferably, the height (H) of the segment 61 satisfies Formula 2, and the maximum height of the segment 61 can be limited.

[0236] Figure 7e is used to determine the maximum value (h max ) concept map.

[0237] Reference Figure 7e In the winding structure of the electrode assembly, the electrode (E 1 ) facing the electrode of opposite polarity (E 2 ), and the diaphragm S is inserted between them in the radial direction. 1 ) are coated with active material layers (E 1，active ), and the electrode (E 2 ) are also coated with active material layers (E 2，active For electrical insulation, the end of the diaphragm S (S end ) can also be obtained from the electrode (E 2 ) end (E 2，end ) extends outward to the insulation gap (W gap ) corresponding to the length. In addition, for electrical insulation, the electrode (E 1 ) does not extend further outward beyond the electrode (E 2 ) end. Therefore, the insulation gap (W gap ) corresponding to the area. In addition, when the winding electrode (E 1 、E 2 ) and diaphragm S, the end of diaphragm S (S end ) causes meandering. Therefore, in order to expose the section 61 to the outside of the diaphragm S, an area (W corresponding to the minimum meandering margin of the diaphragm S) must be allocated to the uncoated portion 43. margin，min In addition, for cutting the segments 61, a minimum cutting waste allowance (W scrap,min ). Therefore, the maximum value (h ) of the height of the segment 61 in the variable height region of the segment 61 can be determined by the following formula 3. max ). In formula 3, W foil Corresponds to the width of the current collector foil before it is cut.

[0238] <Formula 3>

[0239] h max =W foil -W scrap,min -W margin,min -W gap

[0240] Preferably, when the first electrode is a positive electrode, the insulating gap W gap It can be 0.2 mm to 6 mm. In addition, when the first electrode is a negative electrode, the insulating gap W gap It can be 0.1mm to 2mm.

[0241] Preferably, the minimum cutting waste amount W scrap,min It can be 1.5 mm to 8 mm. Depending on the process of forming the segment 61, the minimum cutting waste allowance (W scrap,min ). For example, the cutting groove 63 may be formed so that the upper edge of the segment 61 and the upper edge of the current collector foil coincide with each other. In this case, in Formula 3, W scrap,min Can be 0.

[0242] Preferably, the minimum meandering margin W of the diaphragm is margin,min It can be from 0mm to 1mm.

[0243] In one example, the minimum cutting waste allowance (W scrap,min ) can be 1.5 mm, and the minimum meander margin (W margin，min ) may be 0.5 mm. Under this condition, the width (W) of the current collector foil before forming the segment 61 is foil ) is 8mm to 12mm and the insulation gap (W gap ) is 0.6 mm, 0.8 mm and 1.0 mm, the maximum value (h) of the height of the segment 61 can be calculated using Formula 3 as shown in Table 3 below: max ).

[0244] [Table 3]

[0245]

[0246] Considering Table 3, the maximum value (h max ) can be set to 10 mm. Therefore, in the variable height region of the segment 61, the height of the segment 61 satisfies Formula 2 and can be gradually or gradually increased in the range of 2 mm to 10 mm along the radial direction of the electrode assembly. Figure 7b , the pitch (P) of the segments 61 can be adjusted within a range of 0.05 mm to 1.0 mm. If the pitch (P) is less than 0.05 mm, cracks may occur in the uncoated portion 43 near the lower end of the cut groove 63 due to stress when the electrode 60 travels in a winding process or the like. In addition, if the pitch (P) exceeds 1 mm, a region or an empty space (gap) where the segments 61 do not overlap each other sufficiently to sufficiently ensure welding strength may occur when the segments 61 are bent.

[0247] In addition, when the current collector 41 of the electrode 60 is made of aluminum, it is more preferable to set the pitch (P) to 0.5 mm or more. When the pitch (P) is 0.5 mm or more, even if the electrode 60 travels at a speed of 100 mm / sec or more under a tension of 300 gf or more in a winding process or the like, cracks can be prevented from occurring at the bottom of the cut groove 63.

[0248] According to the experimental results, when the current collector 41 of the electrode 60 is an aluminum foil with a thickness of 15 μm and the pitch (P) is 0.5 mm or more, no cracks are generated at the bottom of the cutting groove 63 when the electrode 60 travels under the above travel conditions.

[0249] like Figure 7b As shown, the cutting groove 63 is inserted between two adjacent sections 61 in the winding direction X. The cutting groove 63 corresponds to the space formed by removing the uncoated portion 43. Preferably, the edges at both ends of the lower portion of the cutting groove 63 have an arch shape. That is, the cutting groove 63 includes a substantially flat bottom 63a and an arch portion 63c. The arch portion 63c connects the bottom 63a and the side 63b of the section 61. In a modified example, the bottom 63a of the cutting groove 63 can be replaced with an arc shape. In this case, the side 63b of the section 61 can be smoothly connected by the arc shape of the bottom 63a.

[0250] The radius of curvature of the rounded portion 63c may be greater than 0 and less than or equal to 0.5 mm, preferably greater than 0 and less than or equal to 0.1 mm, more preferably 0.01 mm to 0.05 mm. When the radius of curvature of the rounded portion 63c satisfies the above numerical range, cracks can be prevented from occurring in the lower portion of the cutting groove 63 when the electrode 60 is traveling in a winding process, etc.

[0251] The lower inner angle (θ) of the plurality of segments 61 may increase from the core toward the periphery. In one example, the lower inner angle (θ) of the plurality of segments 61 may increase gradually or stepwise from the core toward the periphery. The lower inner angle (θ) is the angle between a straight line extending from the bottom 63a of the cutting groove 63 and a straight line extending from the side 53b of the segment 61. When the segment 61 is symmetrical in the left-right direction, the lower inner angles (θ) of the left and right sides are substantially the same.

[0252] If the radius of the electrode assembly increases, the radius of curvature increases. If the lower inner angle (θ) of the segment 61 increases as the radius of the electrode assembly increases, the stress generated in the radial direction and the circumferential direction when the segment 61 is bent can be reduced. In addition, if the lower inner angle (θ) increases, when the segment 61 is bent, the area overlapped with the segment 61 on the inside and the number of overlapping layers also increase, so that the welding strength can be uniformly ensured in the radial direction and the circumferential direction, and the bending surface area can be formed to be flat.

[0253] Preferably, the lower inner angle (θ) may be determined by the radius of the winding turn where the segment 61 is located and the width (D) of the segment 61 .

[0254] Figure 7f It is a schematic diagram for explaining the formula for determining the lower interior angle (θ) of the segment 61 .

[0255] Reference Figure 7f , the sides of segment 61 ideally coincide with line segments AE and DE, which connect the core center (E) to the two end points A and D of line segment AD corresponding to the width (D) of segment 61.

[0256] When the edge of the segment 61 extends in the most ideal direction, assuming that the line segment EF is approximately equal to the line segment AE and the line segment DE, the lower inner angle (θ) of the segment 61 can be approximately determined by the following formula 4 according to the width (D) of the segment 61 and the radius (r) of the winding turn where the segment 61 is located. refer ).

[0257] <Formula 4>

[0258]

[0259] The angle in equation 4 is the lower interior angle (θ refer ). In addition, there is a spacing (P) between adjacent segments 61 in the same winding turn. The length of the spacing (P) is represented by p. Since there is a spacing (P) between adjacent segments 61, a tolerance of 50% of the spacing (p) can be given to the lower internal angle (θ). That is, the width of the upper side BC of the segment 61 can be increased by a maximum of p / 2 to the upper side B′C′. The lower internal angle (θ′) reflecting the tolerance can be expressed by the following formula 5. The lower internal angle (θ refer ) is an ideal standard angle ∠BAG, and the lower inner angle (θ′) is an angle ∠B′AG′ reflecting a tolerance according to the pitch (p). In Formula 5, H is the height of the segment 61, and p corresponds to the pitch.

[0260] <Formula 5>

[0261]

[0262] Preferably, the lower inner angle (θ) of the segment 61 located at each winding turn of the electrode assembly may satisfy the following Formula 6. Then, when the segment 61 is bent toward the core center of the electrode assembly, the adjacent segments 61 in the circumferential direction do not interfere with each other and may be bent smoothly.

[0263] <Formula 6>

[0264]

[0265] In one example, when the electrode 60 forms a wound structure having a diameter of 22 mm and a core radius of 4 mm, the lower inner angle of the segment 61 in the height variable region may be gradually or stepwise increased within a range of 60 to 85 degrees.

[0266] In another example, in one group unit or in two or more group units, the lower inner angles (θ) of the plurality of segments 61 may gradually or stepwise increase as proceeding from the core toward the periphery.

[0267] In addition, the lower left inner angle and the lower right inner angle of the segment 61 may be different. However, the lower inner angle (θ) on either side may be designed to satisfy the above-mentioned equation 6.

[0268] Refer again Figure 7a , the width of the first part B1 (d B1 ) is designed so that when the segment 61 of the third portion B2 is bent toward the core, the core of the electrode assembly is opened to the outside by more than 90% of its diameter. B1 ) may increase in proportion to the bending length of the segment 61 of the group 1. The bending length corresponds to the length from the bending point to the upper end side of the segment 61. Preferably, when the electrode 60 is used to manufacture an electrode assembly of a cylindrical battery having a shape factor of 4680, the width (d B1 ) can be set to 180 mm to 350 mm depending on the height of the segment 61 included in the group 1 and the diameter of the core of the electrode assembly.

[0269] The bending point of the segment 61 can be set at a line passing through the lower end of the cutting groove 63 or at a point spaced a predetermined distance upward from the line. When the segment 61 is bent toward the core at a point spaced a certain distance from the lower end of the cutting groove 63, the segments overlap better in the radial direction. When the segment 61 is bent, the segment on the outside presses the segment on the inside based on the center of the core. At this time, if the bending point is spaced a predetermined distance from the lower end of the cutting groove 63, the segment on the inside is pressed by the segment on the outside in the winding axis direction, and the segments overlap better. The spacing distance of the bending points can preferably be less than 1 mm. Since the minimum height of the segment is 2 mm, the ratio of the spacing distance of the bending points to the minimum height can be less than 50%.

[0270] In one embodiment, the width of each segment group may be designed to construct the same winding turns of the electrode assembly. Here, the winding turns may be counted based on the end of the first portion B1 when the electrode 60 is in a wound state.

[0271] In another variation, the width of each segment group may be designed to construct at least one winding turn of the electrode assembly.

[0272] In yet another variation, the width and / or height and / or spacing of the segments 61 belonging to the same segment group may increase or decrease gradually and / or stepwise and / or irregularly within a group or between adjacent groups.

[0273] Groups 1 to 8 are only examples of the segment groups included in the third portion B2. The number of groups, the number of segments 61 included in each group, and the width of the group may preferably be adjusted so that the segments 61 overlap by several layers, so that the stress is dispersed as much as possible during the bending process of the uncoated portion 43, and the welding strength with the current collector is sufficiently ensured.

[0274] In another modification, similar to the first and second embodiments, the height of the second portion B3 may be gradually or stepwise reduced.

[0275] In yet another variation, the segment structure of the third part B2 may extend to the second part B3 (see dotted line). In this case, the second part B3 may also include a plurality of segments like the third part B2. Preferably, the segment structure of the second part B3 may be substantially the same as the segment structure of the outermost segment group of the third part B2. In this case, the segments included in the second part B3 and the third part B2 may have substantially the same width, height and spacing. In a variation example, the segments of the second part B3 may have a width and / or height and / or spacing greater than the width and / or height and / or spacing of the third part B2.

[0276] In the third part B2, the area (groups 1 to 7) where the height of the segment 61 gradually increases based on the winding direction of the electrode 60 can be defined as a segment height variable area, and the last segment group (group 8) can be defined as a height consistent area where the height of the segment is kept consistent.

[0277] That is, in the third part B2, when the height of the segment 61 increases from h 1 Gradually increase to h N When the height is h 1 to h N-1 (N is a height index, a natural number greater than or equal to 2) The area of ​​the segment 61 corresponds to the height variable area, and the height is h N The region where the segment 61 is located corresponds to the height uniform region. The ratio of the height variable region and the height uniform region to the length of the electrode 60 in the winding direction will be described later with reference to the specific embodiment.

[0278] When the electrode 60 is used to manufacture an electrode assembly for a cylindrical battery having a shape factor of 4680, the width (d B1) may be 180 mm to 350 mm. The width of group 1 may be 35% to 40% of the width of the first 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. The width of the second portion B3 (d B3 ) can be 180mm to 350mm similar to the width of the first part B1.

[0279] The width of groups 1 to 8 does not show a constant increase or decrease pattern, because the segment width gradually increases from group 1 to group 8, but the number of segments included in the group is limited to an integer and the thickness of the electrode is slightly deviated in the winding direction. Therefore, the number of segments in a specific segment group can be reduced. Therefore, the width of the group can present an irregular change pattern from the core to the periphery as in the above example.

[0280] That is, assuming that the widths of each of the three segment groups continuously adjacent to each other in the circumferential direction of the electrode assembly in the winding direction are W1, W2 and W3 respectively, the electrode assembly may include a combination of segment groups in which W3 / W2 is less than W2 / W1.

[0281] In a specific example, groups 4 to 6 correspond to the above case. The width ratio of group 5 to group 4 is 120% to 130%, and the width ratio of group 6 to group 5 is 100% to 120%, which is less than 120% to 130%.

[0282] According to yet another variation, when the uncoated portion 43 of the electrode 60 has a segment structure, the electrode 60 may include a segment skipping region 64 in which some of the multiple segments are regularly or irregularly omitted, such as Figure 7g shown.

[0283] Preferably, there may be a plurality of segment skipping regions 64. In one example, the width of the segment skipping region 64 may be constant from the core to the periphery. In another example, the width of the segment skipping region 64 may increase or decrease regularly or irregularly from the core to the periphery. Preferably, the height of the uncoated portion present in the segment skipping region 64 may correspond to the height of the first portion B1 and / or the second portion B3.

[0284] The number of the segments 61 existing between the segment skipping areas 64 may be at least one. Figure 7gAs shown, the electrode 60 may include an uncoated portion in which the number of segments 61 existing between the segment skipping regions 64 increases from the core toward the periphery.

[0285] Preferably, the width of the segment skipping region 64 may be set so that when the electrode 60 is wound, Figure 7h As shown, the segments located in each winding turn may be located within a preset independent area 66 based on the center of the core C of the electrode assembly 65 .

[0286] In other words, when the electrode assembly 65 is viewed in the winding axis direction, the plurality of segments 61 may be located within the plurality of independent regions 66 based on the center of the core C. The number of independent regions 66 may be changed to 2, 3, 4, 5, and the like.

[0287] Preferably, the independent area 66 can be in a fan-shaped shape. In this case, the angles between the independent areas 66 can be substantially the same. In addition, the circumferential angle (δ) of the independent area 66 can be 20 degrees or more, optionally 25 degrees or more, optionally 30 degrees or more, optionally 35 degrees or more, or optionally 40 degrees or more.

[0288] In a variant, the independent area 66 may have a geometric shape such as: square, rectangle, parallelogram, trapezoid, etc.

[0289] In the present disclosure, the shape of the section 61 may be modified in various ways.

[0290] In addition, in the electrode assembly 65 of the present disclosure, the plurality of segments 61 are bent in the radial direction to form a bent surface area F ( Fig.10b ), and the current collector (144, 176) ( Fig.23 ) may be welded to the bent surface region F. Depending on the use environment of the battery, if vibration is applied to the electrode assembly 65 or the electrode assembly 65 expands due to repeated charge and discharge cycles, stress increases at the welding region of the current collector (144, 176), which may cause cracks in the segment 61 welded to the current collector (144, 176) and the active material layer 42 adjacent thereto due to an internal short circuit. For reference, vibration may be applied to the battery from a load device (e.g., an electric vehicle).

[0291] The electrode 60 according to the fourth embodiment of the present disclosure may have a structure capable of releasing stress by setting a cutout portion 62, in which the uncoated portion 43 and / or the segment 61 may be broken at a point sufficiently spaced apart from the active material layer 42 when a stress exceeding a threshold value occurs at a welding region of the current collector.

[0292] Figure 7i : is a plan view showing a first example of forming the cutout portion 62 in the electrode 60 according to the fourth embodiment of the present disclosure.

[0293] Reference Figure 7i In the electrode 60 of the fourth embodiment, the uncoated portion 43 includes a plurality of independently bendable segments 61, and at least a portion of the uncoated portion 43 having the plurality of segments 61 may include a cutout portion 62 extending in a direction parallel to the winding direction.

[0294] The cutout portion 62 may be provided in a region of the non-coating portion 43 between a bottom 63 a of the cut groove 63 and an active material portion where the active material layer 42 is formed.

[0295] The cutout portion 62 may be continuously formed in a direction parallel to the winding direction of the electrode assembly in a region of the non-coating portion 43 having the plurality of sections 61 .

[0296] Preferably, the distance from the bottom 63a of the cutting groove 63 to the cut portion 62 may be smaller than the distance from the cut portion 62 to the insulating coating layer 44. In this case, the point where the uncoated portion 43 is broken may be separated from the active material layer 42 as much as possible to prevent damage to the active material layer 42 and the insulating coating layer 44 when the uncoated portion 43 is broken.

[0297] The spacing distance between the cutout portion 62 and the bottom 63a of the cutting groove 63 may be 0.1 mm to 1.9 mm. If the spacing distance is less than 0.1 mm, cracks may easily occur due to a small impact rather than a threshold stress; if the spacing distance is greater than or equal to 1.9 mm, the threshold may become too large and the fracture area may exceed the cutout portion to reach the active material layer.

[0298] The cutout portion 62 may include an array of a plurality of perforations 62h along the winding direction X of the electrode assembly. In one example, the perforations 62h may have a circular shape. The shape of the perforations 62h may be replaced by a square, diamond, triangle, or elliptical shape.

[0299] Although not shown in the drawings, the cutout portion 62 may include an array of a plurality of grooves along the winding direction X of the electrode assembly. Here, the groove refers to a region where the thickness of the uncoated portion 43 is locally reduced. The groove may have a circular, square, diamond, triangular, or elliptical shape.

[0300] Figure 7j : is a plan view showing a second example of forming the cutout portion 62 in the electrode 60 according to the fourth embodiment of the present disclosure.

[0301] Reference Figure 7j , the cutout portion 62 may be discontinuously formed in a region of the non-coating portion 43 having the plurality of sections 61 in a direction parallel to the winding direction of the electrode assembly.

[0302] That is, the cutout portion 62 may include a plurality of sub-cutout portions 62s discontinuously formed in a direction parallel to the winding direction X of the electrode assembly, and the plurality of sub-cutout portions 62s may have substantially the same height in the winding axis direction Y.

[0303] In one aspect, in at least a portion of the uncoated portion 43, the length of the sub-cut portion 62s along the winding direction X of the electrode assembly may gradually increase. Alternatively, in at least a portion of the uncoated portion 43, the length of the sub-cut portion 62s along the winding direction X of the electrode assembly may gradually decrease.

[0304] On the other hand, in at least a portion of the uncoated portion 43, the spacing distance between adjacent sub-cut portions 62s may gradually increase along the winding direction X of the electrode assembly. Alternatively, in at least a portion of the uncoated portion 43, the spacing length between adjacent sub-cut portions 62s may gradually decrease along the winding direction X of the electrode assembly.

[0305] Preferably, an area where the length of the sub-cut portions 62s in the uncoated portion 43 relatively increases or the spacing distance between adjacent sub-cut portions 62s relatively decreases may correspond to an increase in stress applied to the segment 61 welded to the current collector due to vibration or expansion of the electrode assembly.

[0306] Figure 7k and Figure 7l 2 are plan views showing third and fourth examples of forming the cutout portion 62 in the electrode 60 according to the fourth embodiment of the present disclosure.

[0307] Reference Figure 7k and Figure 7l The cut portion 62 includes a plurality of sub-cut portions 62s discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the uncoated portion 43 may include regions in which heights of the sub-cut portions 62s in the winding axis direction Y are different from each other.

[0308] In one example, if Figure 7k As shown, the cut portion 62 includes a plurality of sub-cut portions 62s formed discontinuously in a direction parallel to the winding direction of the electrode assembly, and the uncoated portion 43 may include an area where the distance between the bottom 63a of the cutting groove 63 and the sub-cut portion 62s gradually decreases along the winding direction X of the electrode assembly.

[0309] In another example, if Figure 7lAs shown, the cut portion 62 includes a plurality of sub-cut portions 62s formed discontinuously along a direction parallel to the winding direction X of the electrode assembly, and the uncoated portion 43 may include an area where the distance between the bottom 63a of the cutting groove 63 and the sub-cut portion 62s gradually increases along the winding direction X of the electrode assembly.

[0310] Preferably, a region where the distance between the sub-cut portion 62s in the uncoated portion 43 and the bottom 63a of the cutting groove 63 is relatively reduced may correspond to a region where stress applied to the segment 61 welded to the current collector increases due to vibration or expansion of the electrode assembly.

[0311] Figure 7m is a plan view showing a fifth example of forming the cutout portion 62 in the electrode 60 according to the fourth embodiment of the present disclosure.

[0312] Reference Figure 7m The cutout portion 62 includes a plurality of sub-cutout portions 62 s , and the plurality of sub-cutout portions 62 s may be disposed at positions corresponding to the bottom 63 a of the cutting groove 63 .

[0313] Preferably, the sub-cut portion 62 s may intersect with an imaginary line L passing through the center of the upper side and the center of the lower side of the segment 61 .

[0314] Based on the distance between the bottom 63 a of the cutting groove 63 and the imaginary line L, the sub-cut portion 62 s and the imaginary line L may be separated by more than 50%.

[0315] In the area where the sub-cut portion 62s is located, the resistance is locally increased. This is because the cross-sectional area of ​​the area where the sub-cut portion 62 is provided in the uncoated portion 43 is reduced. According to the fifth example, the increase in resistance due to the sub-cut portion 62s can be suppressed by reducing the area where the sub-cut portion 62s overlaps with the segment 62 forming the current path.

[0316] Figure 7n : is a plan view showing a sixth example of forming the cutout portion 62 in the electrode 60 according to the fourth embodiment of the present disclosure.

[0317] Reference Figure 7n The cutout portion 62 includes a plurality of sub-cutout portions 62s, and the plurality of sub-cutout portions 62s may be disposed to overlap with the bottom 63a of the cutting groove 63 disposed at both sides of the segment 61 welded to the current collector.

[0318] Preferably, the sub-cut portion 62s may not intersect with an imaginary line L passing through the center of the upper side and the center of the lower side of the segment 61 welded to the current collector.

[0319] Based on the distance between the bottom 63 a of the cutting groove 63 and the imaginary line L, the sub-cut portion 62 s and the imaginary line L may be separated by more than 50%.

[0320] In the section 61 welded to the current collector, the area close to the imaginary line L corresponds to a main path through which the charging and discharging current flows. If the sub-cut portion 62s and the imaginary line L do not intersect each other, the resistance of the section 61 forming the current path can be suppressed from increasing due to the sub-cut portion 62s.

[0321] In the first to sixth examples described above, unlike the drawings, the height of the segment 61 may be substantially the same along the winding direction X of the electrode assembly. Therefore, when the cutout portion 62 is provided in the electrode 60 , the height of the segment 61 may vary or remain constant along the winding direction X of the electrode assembly.

[0322] Figure 8a : is a plan view showing the structure of an electrode 70 according to a fifth embodiment of the present disclosure.

[0323] Reference Figure 8a , the electrode 70 of the fifth embodiment is substantially the same as that of the previous embodiment except that the shape of the segment 61' is different. Therefore, unless otherwise described, the configuration of the fourth embodiment is equally applicable to the fifth embodiment.

[0324] The segment 61' has a geometric figure with substantially equal widths at the top and bottom. Preferably, the segment 61' may have a rectangular shape.

[0325] Figure 8b is a diagram showing the definition of the width, height, and pitch of the rectangular section 61 ′.

[0326] Reference Figure 8b , the width (D), height (H) and spacing (P) of the section 61′ can be set to prevent the uncoated portion 43 from being torn during the bending of the uncoated portion 43 and to prevent the uncoated portion 43 from abnormally deforming, while sufficiently increasing the number of overlapping layers of the uncoated portion 43 to improve the welding strength with the current collector. Abnormal deformation means that the uncoated portion below the bending point does not maintain a straight form while falling and deforms irregularly.

[0327] The width (D) of the segment 61′ is defined as the length between two points where two straight lines extending from both sides of the segment 61′ intersect with a straight line extending from the bottom 63a of the cutting groove 63. The height (H) of the segment 61′ is defined as the shortest distance between the uppermost edge of the segment 61′ and a straight line extending from the bottom 63a of the cutting groove 63. The pitch (P) of the segment 61′ is defined as the length between two points where a straight line extending from the bottom 63a of the cutting groove 63 intersects with straight lines extending from both sides 63b connected to the bottom 63a. When the side 63b and / or the bottom 63a are curved, the straight line may be replaced by a tangent line extending from the side 63b and / or the bottom 63a at the intersection where the side 63b and the bottom 63a intersect.

[0328] Preferably, the conditions of the width (D), height (H) and spacing (P) of the segment 61' are substantially the same as those of the fourth embodiment described above, and are therefore not described again. However, since the segment 61' has a rectangular shape, the lower inner angle of the segment 61' may be constant at 90 degrees.

[0329] Similar to the electrode 60 of the fourth embodiment, the electrode 70 according to the fifth embodiment may also include a segment skipping region 64 in which some segments of the plurality of segments are regularly or irregularly omitted, such as Figure 8c shown.

[0330] In addition, when the electrode 70 including the segment skipping region 64 is wound into an electrode assembly, the segments can be located in multiple independent regions 66, such as Figure 7h shown.

[0331] As in the fourth and fifth embodiments, when the third portion B2 and the second portion B3 include a plurality of sections 61 , 61 ′, the shape of each section 61 , 61 ′ may be modified in various ways.

[0332] Preferably, the segment can be deformed into various shapes while satisfying at least one of the following conditions.

[0333] Condition 1: The width of the lower part is greater than the width of the upper part

[0334] Condition 2: The width of the lower part is the same as the width of the upper part

[0335] Condition 3: The width is consistent from bottom to top

[0336] Condition 4: Width decreases from bottom to top

[0337] Condition 5: The width decreases from the bottom to the top and then increases

[0338] Condition 6: The width increases from the bottom to the top and then decreases

[0339] Condition 7: Width increases from bottom to top and then remains consistent

[0340] Condition 8: The width decreases from the bottom to the top and then remains the same

[0341] Condition 9: The interior angle of one side of the lower part is equal to the interior angle of the other side

[0342] Here, the inner angle may be defined as the angle formed by the side of the segment based on the width direction of the lower portion of the segment. If the side is a curve, the inner angle is defined as the angle between the tangent line drawn at the lowermost end of the curve and the width direction of the lower portion of the segment.

[0343] Condition 10: The interior angle of one side of the lower part is different from the interior angle of the other side

[0344] Condition 11: The inner angle of one side of the lower part and the inner angle of the other side of the lower part are acute, right or obtuse respectively Condition 12: The left and right directions are symmetrical based on the winding axis direction

[0345] Condition 13: Asymmetric left-right direction based on winding axis direction

[0346] Condition 14: The side is straight

[0347] Condition 15: The side is curved

[0348] Condition 16: The side protrudes outward

[0349] Condition 17: The side protrudes inward

[0350] Condition 18: The upper and / or lower corners have a structure where straight lines intersect

[0351] Condition 19: The upper and / or lower corners have a structure where a straight line and a curve intersect

[0352] Condition 20: The upper and / or lower corners have a structure where curves intersect

[0353] Condition 21: The upper and / or lower corners have a rounded arch structure

[0354] Fig. 9 2 is a diagram exemplarily showing the shapes of segments according to various modifications of the present disclosure.

[0355] As shown in the accompanying drawings, the segment can have various geometric shapes, wherein the imaginary line connecting the sides of the two cutting grooves on both sides is the base. The geometric shape has a structure connecting at least one straight line, at least one curve, or a combination thereof. In one example, the segment can have a polygonal shape, an arch shape, or various combinations thereof.

[0356] Specifically, the segment may have a bilaterally symmetrical trapezoidal shape ( ); Asymmetric trapezoidal shape ( ); parallelogram shape ( ); triangular shape ( ); pentagonal shape ( ); arc shape ( ); or oval shape ( ).

[0357] Since the shape of the segment is not limited to Fig. 9 The shape shown can therefore be deformed into other polygonal shapes, other arch shapes or combinations thereof to satisfy at least one of the above conditions 1 to 21.

[0358] Polygonal shape in the section , , , and In the embodiment, the corners of the upper and / or lower parts may have a shape in which straight lines intersect, or an arch shape (see shape Magnified view of the upper and / or lower corners).

[0359] Polygonal shape in the section , , , and and the curve shape of the segment , The inner angle (θ 1 ) and the interior angle (θ 2 ) can be the same or different, and the lower inner angle on one side (θ 1 ) and the interior angle (θ 2 ) can be acute, right, or obtuse, respectively. An interior angle is the angle where the base of a geometric figure meets the side. When the sides are curved, a tangent line can be drawn from the point where the base meets the side, instead of a straight line.

[0360] The shape of the side of the section having the polygonal shape may be modified in various ways.

[0361] In one example, the segment shape The side of the ), or may be deformed into inwardly curved sections, such as a shape or .

[0362] In another example, the segment shape The side portion of the can be deformed into a curved straight line in a curved concave section, such as a shape or Although not shown, the segment shape The side portion can be deformed into a straight line that is bent convexly outward.

[0363] The shape of the side sections has been modified in various ways , , , and The inner angle (θ 1 ) and the interior angle (θ 2 ) can be the same or different, and the lower inner angle on one side (θ 1 ) and the interior angle (θ 2 ) can be any of acute angles, right angles and obtuse angles respectively.

[0364] The width of the segment can have various changing patterns from bottom to top.

[0365] In one example, the width of the segment can be consistent from bottom to top (shape In another example, the width of the segment can gradually decrease from bottom to top (shape , , , , and In yet another example, the width of the segment may gradually decrease from bottom to top and then increase (shape and In yet another example, the width of the segment may gradually increase from bottom to top and then decrease (shape In yet another example, the width of the segment may gradually decrease from bottom to top and then remain constant (shape ). Although not shown, the width of the segment may gradually increase from bottom to top and then remain constant.

[0366] In addition, Fig. 9 Among the shapes of the segments shown, the polygonal shape with a flat top can be rotated 180 degrees. In one example, when the segment shape , , or When rotated 180 degrees, the width of the segment can gradually increase from bottom to top. When rotated 180 degrees, the width of the segment can remain consistent from bottom to top and then gradually increase.

[0367] In the above-mentioned embodiment (variation), according to another aspect of the present disclosure, the shapes of the segments 61, 61' can be changed differently according to the region of the third portion B2. In one example, for the region where stress is concentrated, a circular arch shape (e.g., a semicircle, an ellipse, etc.) that is conducive to stress distribution can be adopted, while for the region where stress is relatively low, a polygonal shape with as wide an area as possible (e.g., a square, a trapezoid, a parallelogram, etc.) can be applied.

[0368] In another aspect, the plurality of segments may have different shapes individually, in one group unit, or in two or more group units in one direction parallel to the winding direction of the electrode assembly.

[0369] In the embodiment (variation), the segment structure of the third part B2 can also be applied to the first part B1. However, when the segment structure is applied to the first part B1, a reverse formation phenomenon may occur, in which the end of the first part B1 bends toward the periphery when the segments 61, 61' of the third part B2 are bent according to the radius of curvature of the core. Therefore, even if there is no segment structure in the first part B1, or even if the segment structure is applied, it is desirable to adjust the width and / or height and / or spacing of the segments 61, 61' to be as small as possible to a level that does not cause reverse formation in consideration of the radius of curvature of the core.

[0370] According to yet another aspect of the present disclosure, after the electrodes 60 , 70 are wound into an electrode assembly, sections exposed on the upper and lower portions of the electrode assembly may overlap several layers in a radial direction of the electrode assembly to form a bent surface area.

[0371] Fig.10a is a schematic diagram showing a cross section of a bent surface region F formed by bending the segment 61 toward the core C of the electrode assembly 80. Fig.10a , a cross section of the bent surface area F is shown only on the left side based on the winding axis of the electrode assembly 80. The bent surface area F may be formed at both the upper and lower portions of the electrode assembly 80. Fig.10b is a top perspective view schematically showing an electrode assembly 80 in which a bent surface region F is formed.

[0372] Reference Fig.10a and Fig.10b, the bending surface area F has a structure in which the segments 61 overlap into multiple layers in the winding axis direction. The overlapping direction is the winding axis direction Y. Area ① is a segment skipping area (first part B1) without segments, and areas ② and ③ are areas where the winding turns containing segments 61 are located. Area ② is a highly variable area in which the height of the segment 61 varies, and area ③ is a highly consistent area in which the height of the segment remains consistent until the periphery of the electrode assembly. As will be described later, the lengths of areas ② and ③ in the radial direction may be variable. In addition, the uncoated portion (second part B3) included in at least one winding turn including the outermost winding turn may not include a segment structure. In this case, the second part B3 can be excluded in area ③.

[0373] In region ②, the height of the segment 61 may be within the radius r of the electrode assembly 80. 1 To r N The area from the minimum height h 1 (=h min ) gradually changes to the maximum height h N (=h max ). The height variable region of the height variation of the segment 61 is r 1 To r N . From the radius r of the electrode assembly 80 N To the radius R, the height of the segment 61 is kept uniformly at h N . Height consistency means that the height deviation is within 5%.

[0374] At any radial position in region ② and region ③, the number of stacked segments 61 varies according to the radial position. In addition, the number of stacked segments 61 can be varied according to the width of region ②, the minimum height (h 1 ) and maximum height (h N ), and the height variation (Δh) of the segment 61. The stacking number of the segments 61 is the number of segments intersecting with the imaginary line when an imaginary line is drawn from any radial position of the electrode assembly 80 in the winding axis direction.

[0375] Preferably, the stacking number of segments 61 at each position of the bending surface area F can be optimized according to the welding strength required for the current collector by adjusting the height, width and spacing of the segments 61 according to the radius of the winding turn including the segments 61 .

[0376] First, in the height variable region (②) of the segment 61, when the minimum height (h 1 ) are the same, the stacking number of the segment 61 will be described by a specific embodiment according to the maximum height (h N ) changes along the radial direction of the bending surface area F.

[0377] The electrode assemblies of Embodiments 1-1 to 1-7 were prepared. The electrode assemblies of the embodiments had a radius of 22 mm and a core diameter of 4 mm. The positive electrode and the negative electrode included in the electrode assemblies had Figure 7a The electrode structure shown. That is, the segment has a trapezoidal shape. The second part B3 of the positive electrode and the negative electrode does not contain a segment. The length of the second part B3 is 3% to 4% of the total length of the electrode. The positive electrode, the negative electrode and the separator are arranged in accordance with Figure 2 The winding turns are between 48 and 56, but the winding turns of the present embodiment are 51. The thicknesses of the positive electrode, negative electrode and separator are 149 μm, 193 μm and 13 μm, respectively. The thicknesses of the positive electrode and the negative electrode are the thicknesses including the thickness of the active material layer. The thicknesses of the positive electrode current collector and the negative electrode current collector are 15 μm and 10 μm, respectively. The lengths of the positive electrode and the negative electrode in the winding direction are 3948 mm and 4045 mm, respectively.

[0378] In each embodiment, the minimum height of the segment 61 is set to 3mm, so that the height variable area (②) of the segment 61 starts with a radius of 5mm. In addition, in each embodiment, the height of the segment 61 increases by 1mm for every 1mm increase in radius, and the maximum height of the segment 61 is changed in various ways from 4mm to 10mm.

[0379] Specifically, in embodiment 1-1, the height variable area (②) of segment 61 is 5mm to 6mm, and the height of segment 61 is variable from a radius of 3mm to 4mm. In embodiment 1-2, the height variable area (②) of segment 61 is 5mm to 7mm, and the height of segment 61 is variable from 3mm to 5mm. In embodiment 1-3, the height variable area (②) of segment 61 is 5mm to 8mm, and the height of segment 61 is variable from 3mm to 6mm. In embodiment 1-4, the height variable area (②) of segment 61 is 5mm to 9mm, and the height of segment 61 is variable from 3mm to 7mm. In embodiment 1-5, the height variable area (②) of segment 61 is 5mm to 10mm, and the height of segment 61 is variable from 3mm to 8mm. In embodiment 1-6, the height variable area (②) of segment 61 is 5mm to 11mm, and the height of segment 61 is variable from 3mm to 9mm. In embodiments 1-7, the height variable region (②) of segment 61 is 5 mm to 12 mm, and the height of segment 61 is variable from 3 mm to 10 mm. In embodiments 1-1 to 1-7, the height of segment 61 is consistent from the radius corresponding to the upper limit of the height variable region (②) to the periphery. In one example, in embodiment 1-7, the height of segment 61 is consistent at 10 mm from a radius of 12 mm to 22 mm. At this time, in the electrode assembly of the comparative example, the height of segment 61 is maintained at a single height of 3 mm from a radius of 5 mm to a radius of 22 mm.

[0380] Fig.10c 1-1 to 1-7 and the comparative example, in the bent surface area F of the positive electrode formed at the upper part of the electrode assembly, the number of stacked segments in the radial direction is counted. The bent surface area of ​​the negative electrode also shows substantially the same result. The horizontal axis of the graph is the radius based on the center of the core, and the vertical axis of the graph is the number of stacked segments counted at each radial point, which also applies in the same manner to the later-described Fig.10d and Fig.10e .

[0381] Reference Fig.10c , the stacking number uniform region b1 of the segment is shown in common in Embodiments 1-1 to 1-7 and Comparative Example 1. The stacking number uniform region b1 is a radial region of the flat area in each figure. The length of the stacking number uniform region b1 increases as the maximum height of the segment decreases, and the stacking number uniform region b1′ of the comparative example is the longest. In addition, the stacking number of the segment increases as the maximum height (h N ) increases. That is, when the maximum height of the segment (h N) increases so that the width of the variable height region (②) of the segment increases, the number of stacking of the segment increases, and at the same time, the width of the region b1 with consistent stacking number decreases. Outside the region b1 with consistent stacking number, there appears a region b2 with reduced stacking number in which the number of stacking of the segment decreases as the radius increases. The region b2 with reduced stacking number is a radial region in which the number of stacking of the segment decreases as the radius of the electrode assembly increases. The region b1 with consistent stacking number and the region b2 with reduced stacking number are adjacent to each other in the radial direction and complementary. That is, when the length of one region increases, the length of the other region decreases. In addition, in the region b2 with reduced stacking number, the number of stacking decreases in proportion to the distance away from the region b1 with consistent stacking number.

[0382] From the perspective of the number of stacked segments, in embodiments 1-1 to 1-7, in the stacked number uniform region b1, the number of stacked segments is 10 or more. The region where the number of stacked segments is 10 or more can be set as a desired welding target region. The welding target region is a region where at least a portion of the current collector can be welded.

[0383] In Embodiments 1-1 to 1-7, the stacking number uniform region b1 starts from the radius point where the height variable region (②) of the segment starts. That is, the height variable region (②) starts with a radius of 5 mm and extends toward the periphery.

[0384] In Embodiments 1-1 to 1-7 and Comparative Example 1, for the positive electrode, the following Table 4 shows the calculation results of the following ratios: Segment skipping region ( Fig.10a The ratio of the length of c, ①) in the figure to the radius (ba) of the electrode assembly excluding the core; the ratio (e / f) of the length of the region b1 with consistent stacking number to the length (f) from the radius point (5mm) starting from the region with consistent stacking number; the ratio (d / f) of the length of the variable height region of the segment to the length (f) from the radius point (5mm) starting from the region with consistent stacking number to the outermost point (22mm) of the electrode assembly; the ratio (h) of the length of the electrode region corresponding to the segment skipping region (first part B1) to the entire length of the electrode; the ratio (i) of the length of the electrode region corresponding to the variable height region to the entire length of the electrode; and the ratio (i) of the length of the electrode region corresponding to the highly consistent region to the entire length of the electrode, etc.

[0385] Except that the negative electrode shows a difference of 0.1% to 1.2% in parameter h, the other parameters are basically the same as the positive electrode. The sum of the ratios h, i and j is slightly different from 100%. The reason is that there is an area without segments in the second part B3 corresponding to the uncoated portion of the periphery of the electrode. For example, in embodiment 1-1, there is no line segment in the second part B3 corresponding to about 3% of the entire length of the electrode. In Table 4, a to f are parameters based on the length in the radial direction, while h, i and j are parameters based on the length of the electrode in the longitudinal direction before the electrode is wound into an electrode assembly. In addition, the parameters corresponding to the ratio (%) are values ​​rounded to one decimal place. These points are basically the same as Tables 5 and 6 described later.

[0386] [Table 4]

[0387]

[0388] Referring to embodiments 1-1 to 1-7 of Table 4, the number of stacking segments is 11 to 27, and the ratio (d / f) of the highly variable region (d) to the segment region f containing the segment is 6% to 41%. In addition, the ratio (e / f) of the stacking number consistent region (e) to the segment region f containing the segment is 47% to 82%. In addition, the segment skipping region ( Fig.10a The ratio of c, ①) to the radius (ba) of the electrode assembly excluding the core (c / (ba)) is 15%. In addition, the ratio of the length of the electrode area corresponding to the segment skipping area (first part B1) to the entire length of the electrode is 6%, the ratio of the length of the electrode area corresponding to the highly variable area to the entire length of the electrode is 3% to 32%, and the ratio of the length of the electrode area corresponding to the highly consistent area to the entire length of the electrode is 59% to 87%. In all embodiments 1-1 to 1-7, the stacking number (g) of the stacking number consistent area is greater than 10. The stacking number consistent area (e) decreases as the highly variable area (d) of the segment increases, but the stacking number (g) of the segment increases in the stacking number consistent area (e). Preferably, the stacking number consistent area (e) in which the stacking number (g) of the segment is greater than 10 can be set as the welding target area.

[0389] In cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is about 9mm to 10mm. Therefore, for conventional cylindrical batteries, as in embodiments 1-1 to 1-7, the length (f) of the segment area in the radial direction cannot be ensured to be at the level of 17mm, and the length (e) of the region with the same number of stacking cannot be ensured to be at the level of 8mm to 14mm. This is because, in conventional cylindrical batteries, when the radius of the core is designed to be 2mm (the same as in embodiments 1-1 to 1-7), the radial area of ​​the segment can be set to be basically only 7mm to 8mm. In addition, in conventional cylindrical batteries, the length of the electrode in the winding direction is about 600mm to 980mm. This short length of the electrode is only about 15% to 24% of the length of the electrode used in embodiments 1-1 to 1-7 (positive electrode 3948mm, negative electrode 4045mm). Therefore, the numerical ranges of parameters h, i and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0390] Next, when in the highly variable region of the segment ( Fig.10a The maximum height of the middle section (h N ) are the same, the number of stacked segments is described by a specific implementation method according to the minimum height (h 1 ) changes along the radial direction of the bending surface area F.

[0391] The electrode assemblies of Embodiments 2-1 to 2-5 have a radius of 22 mm and a diameter of the core C of 4 mm. Fig.10a In ②), the minimum height (h 1 ) is the same as 4mm, and the maximum height (h N ) varies from 6 mm to 10 mm in increments of 1 mm. Therefore, in the electrode assemblies of embodiments 2-1 to 2-5, the height variable area of ​​the segment ( Fig.10a ②) have widths of 2mm, 3mm, 4mm, 5mm and 6mm respectively, and the segment skips the area ( Fig.10a ①) in the figure is a radial area with a radius of 2mm to 6mm.

[0392] The electrode assemblies of Embodiments 3-1 to 3-4 have a radius of 22 mm and a diameter of the core C of 4 mm. Fig.10a In ②), the minimum height (h 1 ) are the same as 5mm, and the maximum height (h N ) varies from 7 mm to 10 mm in increments of 1 mm. Therefore, in the electrode assemblies of embodiments 3-1 to 3-4, the height variable region of the segment ( Fig.10a②) in have widths of 2mm, 3mm, 4mm and 5mm respectively, and the segment skips the area ( Fig.10a ①) in the figure is the radial area with a radius of 2mm to 7mm.

[0393] The electrode assemblies of Embodiments 4-1 to 4-3 have a radius of 22 mm and a diameter of the core C of 4 mm. Fig.10a In ②), the minimum height (h 1 ) are the same as 6mm, and the maximum height (h N ) varies from 8 mm to 10 mm in increments of 1 mm. Therefore, in the electrode assemblies of embodiments 4-1 to 4-3, the height variable region of the segment ( Fig.10a The widths of ②) are 2mm, 3mm and 4mm respectively, and the segment skipping area ( Fig.10a ①) in the figure is a radial area with a radius of 2mm to 8mm.

[0394] The electrode assembly of Embodiments 5-1 to 5-2 has a radius of 22 mm and a diameter of the core C of 4 mm. Fig.10a In ②), the minimum height (h 1 ) are the same as 7mm, and the maximum height (h N ) varies from 9 mm to 10 mm in increments of 1 mm. Therefore, in the electrode assemblies of embodiments 5-1 to 5-2, the height variable region of the segment ( Fig.10a The widths of ②) in the figure are 2mm and 3mm respectively, and the segment skipping area ( Fig.10a ①) in the figure is the radial area with a radius of 2mm to 9mm.

[0395] Fig.10d : is a graph showing the result of counting the number of stacked sections in the radial direction in the bent surface region F of the positive electrode formed at the upper portion of the electrode assembly according to Embodiments 2-1 to 2-5, Embodiments 3-1 to 3-4, Embodiments 4-1 to 4-3, and Embodiments 5-1 to 5-2. The bent surface region of the negative electrode also shows substantially the same result.

[0396] exist Fig.10d Graph (a) shows the result of counting the number of stacking sections along the radial direction in the bending surface area F for embodiments 2-1 to 2-5, graph (b) is for embodiments 3-1 to 3-4, graph (c) is for embodiments 4-1 to 4-3, and graph (d) is for embodiments 5-1 to 5-2.

[0397] Reference Fig.10d, a region b1 of uniform stacking quantity of the segments appears in all embodiments. The region b1 of uniform stacking quantity is a radial region of the flat region in the curve graph. 1 ) are the same, the length of the region b1 with the same number of stacking is proportional to the maximum height of the segment (h N ) decreases and increases. In addition, when the maximum height of the segment (h N ) are the same, the length of the stacking number consistent region b1 increases with the minimum height of the segment (h 1 ) decreases and increases. In addition, in the stacking number uniform region b1, the stacking number of segments increases with the maximum height (h N Even in the embodiment, a stacking number reduction region b2 appears near the stacking number uniform region b1.

[0398] In all embodiments, the stacking number of the segments in the stacking number uniform region b1 is greater than or equal to 10. Preferably, a region where the stacking number of the segments is greater than or equal to 10 may be set as a desired welding target region.

[0399] In the embodiment, the stacking number uniform region b1 is formed from the segment height variable region ( Fig.10a In embodiments 2-1 to 2-5, the height variable region of the segment ( Fig.10a ②) starts from 6 mm and extends toward the periphery. In embodiments 3-1 to 3-4, the height variable area of ​​the segment ( Fig.10a ②) in starts from 7 mm and extends toward the periphery. In embodiments 4-3 to 4-3, the height variable area of ​​the segment ( Fig.10a ②) starts from 8 mm and extends toward the periphery. In embodiments 5-1 to 5-2, the height variable area of ​​the segment ( Fig.10a ②) in the figure starts from 9 mm and extends toward the periphery.

[0400] Table 5 below shows the calculation results of various parameters including the following for embodiments 2-1 to 2-5, embodiments 3-1 to 3-4, embodiments 4-1 to 4-3 and embodiments 5-1 to 5-2: the ratio (e / f) of the length of the region with consistent stacking number to the length from the radius point (6mm, 7mm, 8mm, 9mm) starting from the region with consistent stacking number to the outermost point (22mm) of the electrode assembly; the ratio (d / f) of the length of the variable height region (②) of the segment to the length from the radius point (6mm, 7mm, 8mm, 9mm) starting from the region with consistent stacking number to the outermost point (22mm) of the electrode assembly, and so on.

[0401] [Table 5]

[0402]

[0403] and Fig.10a and Fig.10d Referring to the embodiments 2-5, 3-4, 4-3, and 5-2 of Table 5, the maximum height (h N ) is the same as 10mm, but the minimum height of the segment (h1) increases to 4mm, 5mm, 6mm and 7mm by 1mm, and the length of the height variable area (②) decreases to 6mm, 5mm, 4mm and 3mm by 1mm. In the four embodiments, the ratio (e / f) of the area with the same number of stacking layers is the largest in embodiment 2-5, which is 69%, and the smallest in embodiment 5-2, which is 38%, and the number of stacking layers in the area with the same number of stacking layers is the same. According to the results shown in Table 5, when the maximum height of the segment (h1) is increased to 4mm, 5mm, 6mm and 7mm by 1mm, and the length of the height variable area (②) is reduced to 6mm, 5mm, 4mm and 3mm by 1mm. N ) are the same, it can be understood that as the width of the variable region (②) of the segment height increases due to the minimum height of the segment (h 1 ) decreases and increases, and the width of the region with the same number of stacking layers also increases proportionally. The reason is that as the minimum height of the segment (h 1 ) is smaller, the radius point where the segment starts is closer to the core, so the area where the segments are stacked expands toward the core.

[0404] Referring to Table 5, it can be found that the number of stacking segments is 16 to 26, the ratio (d / f) of the highly variable region (②) of the segment is 13% to 38%, and the ratio (e / f) of the region with the consistent number of stacking segments is 31% to 69%. In addition, the ratio (c / (ba)) of the segment skipping region (①) to the radius (ba) of the electrode assembly excluding the core is 20% to 35%. In addition, the ratio of the length of the electrode region corresponding to the segment skipping region (①) to the entire length of the electrode is 10% to 20%, the ratio of the length of the electrode region corresponding to the highly variable region (②) to the entire length of the electrode is 6% to 25%, and the ratio of the length of the electrode region corresponding to the highly consistent region (③) to the entire length of the electrode is 62% to 81%.

[0405] In cylindrical batteries with form factors of 1865 and 2170, the electrode assembly has a radius of about 9mm to 10mm. Therefore, unlike the embodiment, it is impossible to ensure that the length (f) of the segment area in the radial direction is at the level of 13mm to 16mm, and it is impossible to ensure that the length (e) of the stacking number consistent region in which the stacking number of segments is 10 or more is at the level of 5mm to 11mm, while ensuring that the length of the segment skipping region (c, ①) is at the level of about 4mm to 7mm. This is because, in conventional cylindrical batteries, when the radius of the core is designed to be 2mm (which is the same as the embodiment), the radial area of ​​the segment can be set to be basically only 7mm to 8mm. In addition, in conventional round batteries, the length of the electrode in the winding direction is about 600mm to 980mm. This short length of the electrode is only about 15% to 24% of the electrode length in the embodiment (positive electrode 3948mm, negative electrode 4045mm). Therefore, the numerical ranges of the parameters h, i and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0406] Next, in the variable height region (②) of the segment, the minimum height (h 1 ) and maximum height (h N ) are the same, how the stacking number of segments according to the diameter of the core C of the electrode assembly changes along the radial direction of the bending surface area F will be described through a specific embodiment.

[0407] The electrode assemblies of Embodiments 6-1 to 6-6 have a radius of 22 mm and a radius of 4 mm of the core C. In the height variable region (②) of the segment 61, the minimum height (h 1 ) is the same as 3 mm, and the maximum height of the segment (h N ) varies from 5 mm to 10 mm in increments of 1 mm. Therefore, in the electrode assemblies of embodiments 6-1 to 6-6, the widths of the segment height variable regions (②) are 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the segment skipping region (①) is a radial region with a radius of 4 mm to 7 mm.

[0408] The electrode assemblies of Embodiments 7-1 to 7-6 have a radius of 22 mm and a radius of the core C of 2 mm. In the height variable region (②) of the segment 61, the minimum height (h 1 ) is the same as 3 mm, and the maximum height of the segment (h N ) changes from 5 mm to 10 mm in increments of 1 mm. Therefore, in the electrode assemblies of embodiments 7-1 to 7-6, the segment height variable regions (②) have widths of 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, and 7 mm, respectively, and the segment skip regions (①) are all the same as the radial regions with a radius of 2 mm to 5 mm.

[0409] Fig.10e : is a graph showing the result of counting the number of stacked sections measured in the radial direction in the bent surface region F of the positive electrode formed at the upper portion of the electrode assembly according to Embodiments 6-1 to 6-6 and Embodiments 7-1 to 7-6. Basically the same result was found in the bent surface region of the negative electrode.

[0410] exist Fig.10e Graph (a) shows the result of counting the number of stacking of sections measured in the radial direction in the bending surface region F for embodiments 6-1 to 6-6, and graph (b) is for embodiments 7-1 to 7-6.

[0411] Reference Fig.10e , a region b1 of uniform stacking quantity of the segments appears in all embodiments. The region b1 of uniform stacking quantity is a radial region of the flat region in the curve graph. 1 ) are the same, the length of the region b1 with the same number of stacking layers in the radial direction increases with the maximum height of the segment (h N ) decreases and increases. In addition, in the stacking number uniform region b1, the stacking number of segments increases with the maximum height (h N In the embodiment, the stacking number reduction region b2 is identified near the stacking number uniform region b1.

[0412] In all embodiments, the stacking number of segments in the stacking number uniform region b1 is greater than or equal to 10. Preferably, a region where the stacking number of segments is greater than or equal to 10 may be set as a desired welding target region.

[0413] In the embodiment, the stacking number uniform area b1 starts from the radius point where the segment height variable area (②) starts. In embodiments 6-1 to 6-6, the radius where the segment height variable area (②) starts is 7 mm, and in embodiments 7-1 to 7-6, the radius where the segment height variable area (②) starts is 5 mm.

[0414] Table 6 below shows the calculation results of various parameters including the following for embodiments 6-1 to 6-6 and embodiments 7-1 to 7-6: the ratio (e / f) of the length of the region with consistent stacking number to the length from the radius point (7mm, 5mm) starting from the region with consistent stacking number to the outermost point (22mm) of the electrode assembly; the ratio (d / f) of the length of the variable height region (②) of the segment to the length from the radius point (7mm, 5mm) starting from the region with consistent stacking number to the outermost point (22mm) of the electrode assembly, etc.

[0415] [Table 6]

[0416]

[0417] Reference Fig.10a And the embodiments 6-6 and 7-6 of Table 6, the minimum height (h 1 ) and maximum height (h N ) are the same as 3mm and 10mm respectively. However, in embodiment 6-6, the radius of the core is 2mm larger than the radius of the core in embodiment 7-6. Therefore, in embodiment 6-6, the stacking number consistent region (e) and the segment region (f) are 2mm smaller than the stacking number consistent region (e) and the segment region (f) in embodiment 7-6, and the stacking number of the segments is the same in the stacking number consistent region. This result comes from the difference in the core radius. According to the results shown in Table 6, when the width of the height variable region (②) of the segment is the same, it can be understood that as the radius (a) of the core is smaller, the ratio (d / f) of the height variable region (②) decreases, but the ratio (e / f) of the stacking number consistent region increases. Referring to Table 6, it can be found that the stacking number of the segment is 13 to 26, the ratio (d / f) of the height variable region (②) of the segment is 12% to 47%, and the ratio (e / f) of the length of the stacking number consistent region is 40% to 76%. In addition, the ratio (c / (ba)) of the segment skipping region (①) to the radius (ba) of the electrode assembly excluding the core is 15% to 17%. In addition, the ratio of the length of the electrode region corresponding to the segment skipping region (①) to the entire length of the electrode is 6%, the ratio of the length of the electrode region corresponding to the highly variable region (②) to the entire length of the electrode is 7% to 32%, and the ratio of the length of the electrode region corresponding to the highly consistent region (③) to the entire length of the electrode is 59% to 83%.

[0418] For cylindrical batteries with form factors of 1865 and 2170, the radius of the electrode assembly is about 9mm to 10mm. Therefore, unlike the embodiment, it is impossible to ensure that the length of the segment area (f) in the radial direction is at the level of 15mm to 17mm, and at the same time, it is impossible to ensure that the length of the segment area (f) is at the level of 6mm to 13mm when the number of stacking of the segments is more than 10, and at the same time, it is impossible to ensure that the length of the segment skipping area (①) is at the level of about 3mm. This is because, in conventional cylindrical batteries, when the radius of the core is designed to be 2mm to 4mm (which is the same as the embodiment), the radial area of ​​the segment can be set to be basically only 5mm to 8mm. In addition, in conventional round batteries, the length of the electrode in the winding direction is 600mm to 980mm. This short length of the electrode is only about 15% to 24% of the electrode length in the embodiment (positive electrode 3948mm, negative electrode 4045mm). Therefore, the numerical ranges of parameters h, i and j cannot be easily derived from the design specifications of conventional cylindrical batteries.

[0419] Taking into account the data in Tables 4 to 6, in the area where the number of stacking of the segments is consistent, the number of stacking of the segments can be 11 to 26. In addition, the ratio (d / f) of the segment's variable height area (②) can be 6% to 47%. In addition, the ratio (e / f) of the area where the number of stacking is consistent can be 31% to 82%. In addition, the ratio (c / (ba)) of the length of the segment skip area (①) to the radius of the electrode assembly excluding the core can be 15% to 35%. In addition, the ratio of the length of the electrode area corresponding to the segment skip area (①) to the entire length of the electrode (the length in the winding direction) can be 6% to 20%. In addition, the ratio of the length of the electrode area corresponding to the variable height area (②) of the segment to the entire length of the electrode can be 3% to 32%. In addition, the ratio of the length of the electrode area corresponding to the consistent height area (③) of the segment to the entire length of the electrode can be 59% to 87%.

[0420] In addition, the parameters described in Tables 4 to 6 vary according to design factors including: the radius of the core (a); the radius of the electrode assembly (b); the minimum height (h 1 ) and maximum height (h N ); the height change (Δh) of each 1mm radius increment; the thickness of the positive electrode, negative electrode, and separator, etc.

[0421] Therefore, in the area where the number of stacking of the segments is consistent, the number of stacking of the segments can be extended to 10 to 35. The ratio (d / f) of the height variable area (②) of the segment can be extended to 1% to 50%. In addition, the ratio (e / f) of the area where the number of stacking is consistent can be extended to 30% to 85%. In addition, the ratio (c / (ba)) of the length of the segment skip area (①) to the radius of the electrode assembly excluding the core can be extended to 10% to 40%. In addition, the ratio of the length of the electrode area corresponding to the segment skip area (①) to the entire length of the electrode (the length in the winding direction) can be extended to 1% to 30%. In addition, the ratio of the length of the electrode area corresponding to the height variable area (②) of the segment to the entire length of the electrode can be extended to 1% to 40%. In addition, the ratio of the length of the electrode area corresponding to the height consistent area (③) of the segment to the entire length of the electrode can be extended to 50% to 90%. In this embodiment, the maximum height (h) of the segment included in the height variable area (②) and the height consistent area (③) N ) is 2 to 8. For example, referring to Table 4, the height index N of embodiments 1-1 and 1-7 are 2 to 8, respectively. However, the height index N may vary depending on the height variation (Δh) of the segment of the electrode assembly in the radial direction. When the radial length of the height variable region (②) is fixed, if the height variation (Δh) of the segment decreases, the height index N increases accordingly, and vice versa. Preferably, the height index N can be further extended to 2 to 20, preferably to 2 to 30.

[0422] In the bent surface regions F formed at the upper and lower portions of the electrode assembly, the lamination number uniform region may be used as a welding target region of the current collector.

[0423] Preferably, the welding region of the current collector overlaps the stacking number uniform region by at least 50% in the radial direction of the electrode assembly, and a higher overlap ratio is more preferred.

[0424] Preferably, the remaining region of the welding region of the current collector that does not overlap with the region with the uniform stacking number may overlap with a region with a reduced stacking number adjacent to the region with the uniform stacking number in the radial direction.

[0425] More preferably, the remaining area of ​​the welding region of the current collector that does not overlap with the area with the uniform stacking number may overlap with an area in which the segment stacking number is 10 or more in the area with the reduced stacking number.

[0426] It is desirable in terms of welding strength and preventing damage to the separator or active material layer during welding if the current collector is welded to a region where the number of segment stacking is 10 or more. Specifically, it is useful when welding the current collector using a high-power laser having a high transmittance characteristic.

[0427] If a region with a uniform stacking number of 10 or more segments is welded to a current collector using a laser, even if the laser output is increased to improve the welding quality, the region with a uniform stacking number absorbs most of the laser energy to form a weld bead, thereby preventing the diaphragm and active material layer below the bending surface area F from being damaged by the laser.

[0428] In addition, since the number of segments stacked in the laser irradiated area is 10 or more, a weld bead having a sufficient volume and thickness is formed. Therefore, sufficient welding strength can be ensured, and the resistance of the welding interface can be reduced to a level suitable for rapid charging.

[0429] When welding the current collector, the output of the laser can be determined according to the desired welding strength between the bent surface area F and the current collector. The welding strength increases in proportion to the number of stacked sections. This is because the volume of the weld bead formed by the laser increases as the number of stacked sections increases. The weld bead is formed as the material of the current collector and the material of the section melt together. Therefore, when the volume of the weld bead is large, the current collector and the bent surface area are more strongly coupled, and the contact resistance of the welding interface is reduced.

[0430] Preferably, the welding strength can be 2kgf / cm 2 More preferably 4kgf / cm 2 The maximum welding strength may vary depending on the output of the laser welding equipment. In addition, the welding strength may preferably be set to 8 kgf / cm 2 Below, it is more preferably set to 6kgf / cm 2 However, the present disclosure is not limited thereto.

[0431] When the welding strength satisfies the above numerical range, the performance of the welding interface will not deteriorate even if severe vibration is applied to the electrode assembly along the winding axis direction and / or radial direction, and since the volume of the weld bead is sufficient, the resistance of the welding interface can be reduced.

[0432] The laser power that satisfies the welding strength condition varies depending on the laser equipment and can be appropriately adjusted within the range of 250 W to 320 W or within the range of 40% to 100% of the maximum output of the laser provided by the equipment.

[0433] The welding strength can be defined as the tensile force per unit area of ​​the current collector when the current collector begins to separate from the bending surface area F (kgf / cm 2 ). Specifically, after the current collector is fully welded, a tensile force may be applied to the current collector while gradually increasing the magnitude of the tensile force. When the tensile force exceeds a threshold value, the segment begins to separate from the welding interface. At this time, the value obtained by dividing the tensile force applied to the current collector by the area of ​​the current collector is equivalent to the welding strength.

[0434] In the bending surface region F, the segments are stacked in a plurality of layers, and the stacking number of the segments can be increased to a minimum of 10 to a maximum of 35 according to the above-described embodiment.

[0435] The thickness of the positive electrode current collector (foil) constituting the uncoated portion 43 may be 10 μm to 25 μm, and the thickness of the negative electrode current collector (foil) constituting the uncoated portion 43 may be 5 μm to 20 μm. Therefore, the bent surface area F of the positive electrode may include an area where the total stacking thickness of the segment is 100 μm to 875 μm. In addition, the bent surface area F of the negative electrode may include an area where the total stacking thickness of the segment is 50 μm to 700 μm.

[0436] Fig.10f is a top plan view of an electrode assembly showing a stacking number uniform region b1 and a stacking number reduced region b2 in a bent surface region F of segments 61 , 61 ′ according to an embodiment of the present disclosure.

[0437] Reference Fig.10f The area between the two circles represented by the thick solid lines corresponds to the bending surface area F of the segment, the area between the two circles represented by the dotted line corresponds to the stacking number consistent area b1 in which the stacking number of the segment is greater than 10, and the outer area of ​​the stacking number consistent area b1 corresponds to the stacking number reduced area b2.

[0438] In one example, when the current collector (P c ) is welded to the bent surface area F, at the collector (P c ) on the surface of the weld pattern (W p ). Welding pattern (W p ) can have an array of line patterns or dot patterns. p ) corresponds to the welding area and may overlap with the stacking number of segments b1 by more than 50% in the radial direction. p ) may be included in the stacking number uniform region b1, and the welding pattern (W p The rest of the weld pattern (W ) may be included in the laminated number reduction region b2 outside the laminated number uniform region b1. p ) can overlap with the stacking number consistent area b1 in order to maximize the welding strength and reduce the resistance of the welding area.

[0439] The area of ​​the bending surface region F can be defined as the sum of the area of ​​the section's uniform stacking number region b1 and the area of ​​the section's reduced stacking number region b2. Since the ratio (e / f) of the uniform stacking number region b1 is 30% to 85%, preferably 31% to 82%, the ratio of the area of ​​the uniform stacking number region b1 to the area of ​​the bending surface region F can be 9% (30 2 / 100 2 ) to 72% (85 2 / 100 2 ), preferably 10% (31 2 / 100 2 ) to 67% (82 2 / 100 2 ).

[0440] Preferably, the current collector (P c ) The edge of the portion contacting the bending surface area F may cover the ends of the segments 61, 61' bent toward the core C in the last winding turn of the height uniform area (③). In this case, due to the welding pattern (W p ) is in the section 61, 61' by the collector (P c ) is formed in a pressed state, so the current collector (P c ) and the bent surface area F are firmly connected. As a result, since the segments 61, 61' stacked in the winding axis direction are in close contact with each other, the resistance at the welding interface can be reduced and the bulging of the segments 61, 61' can be prevented.

[0441] In addition, the bending direction of the segment may be opposite to that described above. That is, the segment may be bent from the core toward the periphery. In this case, the pattern in which the height of the segment changes along the winding direction (X-axis direction) may be opposite to that of the above-described embodiment (variation). For example, the height of the segment may gradually decrease from the core toward the periphery. In addition, the structure applied to the first part B1 and the structure applied to the second part B3 may be interchanged with each other. Preferably, the height change pattern may be designed so that the height of the segment gradually decreases from the core toward the periphery, but when the segment closest to the periphery of the electrode assembly is bent toward the periphery, the end of the segment does not protrude beyond the periphery of the electrode assembly.

[0442] The electrode structure of the above embodiment (variation) may be applied to at least one of the first electrode and the second electrode having different polarities included in a jellyroll type electrode assembly or other types of electrode assemblies known in the art. In addition, when the electrode structure of the above embodiment (variation) is applied to any one of the first electrode and the second electrode, the conventional electrode structure may be applied to the other. In addition, the electrode structures applied to the first electrode and the second electrode may not be the same, but may be different from each other.

[0443] For example, when the first electrode and the second electrode are respectively a positive electrode and a negative electrode, any one of the above embodiments (variations) can be applied to the first electrode, and the conventional electrode structure (see Figure 1 ) can be applied to the second electrode.

[0444] As another example, when the first electrode and the second electrode are a positive electrode and a negative electrode, respectively, any one of the above embodiments (modifications) may be selectively applied to the first electrode and any one of the above embodiments (modifications) may be selectively applied to the second electrode.

[0445] In the present disclosure, the positive electrode active material coated on the positive electrode and the negative electrode active material coated on the negative electrode may adopt any active material known in the art without limitation.

[0446] In one example, the positive electrode active material may include a x M y ]O 2+z (A includes at least one element selected from Li, Na and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru and Cr; x≥0, 1≤x+y≤2, 0.1≤z≤2; and the stoichiometric coefficients x, y, z and M are selected so that the compound remains electrically neutral).

[0447] In another example, the positive electrode active material may be an alkali metal compound xLiM disclosed in US Pat. No. 6,677,082, US Pat. No. 6,680,143, etc. 1 O 2 -(1-x)Li 2 M 2 O 3 , where M 1 comprising at least one element having an average oxidation state of 3; M 2 comprising at least one element having an average oxidation state of 4; and 0≤x≤1).

[0448] In another example, the positive electrode active material may be a material of the general formula Li a M 1 x Fe 1-x M 2 y P 1-y M 3 z O 4-z (M 1comprises at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, and Al; M 2 comprises at least one element selected from Ti, Si, Mn, Co, Fe, V, Cr, Mo, Ni, Nd, Al, Mg, Al, As, Sb, Si, Ge, V, and S; M 3 comprises a halogen element, optionally including F; 0 < a ≤ 2, 0 ≤ x ≤ 1, 0 ≤ y < 1, 0 ≤ z < 1; the stoichiometric coefficients a, x, y, and z are selected such that the compound remains electrically neutral) or Li 3 M 2 (PO 4 ) 3 A lithium metal phosphate represented by [M comprises at least one element selected from Ti, Si, Mn, Fe, Co, V, Cr, Mo, Ni, Al, Mg, and Al].

[0449] Preferably, the positive electrode active material may include primary particles and / or secondary particles formed by aggregation of primary particles.

[0450] In one example, the negative electrode active material may be a carbon material, a lithium metal or a lithium metal compound, silicon or a silicon compound, tin or a tin compound, etc. Metal oxides having a potential lower than 2V (such as TiO 2 and SnO 2 ) can also be used as the negative electrode active material. As the carbon material, low-crystalline carbon, high-crystalline carbon, etc. can be used.

[0451] The separator may be a porous polymer membrane, for example, a porous polymer membrane made of a polyolefin-based polymer or its laminate such as: ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, ethylene / methacrylate copolymer, etc. As another example, the separator may be a common porous non-woven fabric, for example, a non-woven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc.

[0452] At least one surface of the separator may include a coating layer of inorganic particles. The separator itself may also be made of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure in which they are joined to a binder such that there is an interstitial volume between adjacent particles.

[0453] The inorganic particles may be made of an inorganic material having a dielectric constant of 5 or more. The inorganic particles may include at least one material selected from the group consisting of: Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), PB(Mg3 Nb 2 / 3 ) 3 、PbTiO 3 (PMN-PT), BaTiO 3 、hafnia(HfO 2 )、SrTiO 3 、TiO 2 、Al 2 O 3 、ZrO 2 SnO 2 、CeO 2 , MgO, CaO, ZnO and Y 2 O 3 .

[0454] Hereinafter, the structure of an electrode assembly according to an embodiment of the present disclosure will be described in detail.

[0455] Fig.11 1 is a cross-sectional view of a jellyroll-type electrode assembly 80 in which the electrode 40 according to the first embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode), extracted along the Y-axis direction (winding axis direction).

[0456] Can refer to Figure 2 The winding method described above is used to manufacture the electrode assembly 80. For ease of description, the protruding structure of the first uncoated portion 43a and the second uncoated portion 43b extending to the outside of the separator is shown in detail, and the winding structure of the first electrode, the second electrode and the separator is not drawn. The first uncoated portion 43a protruding upward extends from the first electrode, and the second uncoated portion 43b protruding downward extends from the second electrode.

[0457] The pattern of height variation of the first uncoated portion 43a and the second uncoated portion 43b is schematically shown. That is, the height of the uncoated portion may vary irregularly depending on the position of the cut section. For example, if the side of the trapezoidal segments 61, 61' or the cutting groove 63 is cut, the height of the uncoated portion in the cross section is lower than the height (H) of the segments 61, 61'. Therefore, it should be understood that the height of the uncoated portion shown in the cross-sectional view of the electrode assembly corresponds to the average value of the height of the uncoated portion included in each winding turn ( Figure 7b and Figure 8b H in.

[0458] Reference Fig.11 The first non-coating portion 43 a includes a first portion B1 adjacent to the core of the electrode assembly 80 , a second portion B3 adjacent to the outer circumferential surface of the electrode assembly 80 , and a third portion B2 interposed between the first portion B1 and the second portion B3 .

[0459] The height (length in the Y-axis direction) of the second portion B3 is relatively smaller than that of the third portion B2. Therefore, when the curling portion of the battery case is pressed near the second portion B3, an internal short circuit can be prevented from occurring as the curling portion and the second portion B3 come into contact with each other.

[0460] The second non-coating portion 43b has the same structure as the first non-coating portion 43a. In a variation, the second non-coating portion 43b may have a conventional electrode structure or an electrode structure in other embodiments (variations).

[0461] Ends 81 of the first and second non-coating portions 43a and 43b may be bent in a radial direction (eg, from the periphery toward the core) of the electrode assembly 80. At this time, the second portion B3 may not be substantially bent.

[0462] Fig.12 1 is a cross-sectional view of a jelly-roll type electrode assembly 90 in which the electrode 45 of the second embodiment is applied to a first electrode (positive electrode) and a second electrode (negative electrode), taken along the Y-axis direction (winding axis direction).

[0463] Reference Fig.12 The first uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 90, a second portion B3 adjacent to the outer circumferential surface of the electrode assembly 90, and a third portion B2 interposed between the first portion B1 and the second portion B3.

[0464] The height of the second portion B3 is relatively smaller than that of the third portion B2, and gradually or stepwise decreases from the core toward the periphery. Therefore, when the curling portion of the battery case is pressed near the second portion B3, the phenomenon of internal short circuit due to contact between the curling portion and the second portion B3 can be prevented.

[0465] The second non-coating portion 43b has the same structure as the first non-coating portion 43a. In a modification, the second non-coating portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (modifications).

[0466] Ends 91 of the first and second non-coating portions 43a and 43b may be bent in a radial direction (eg, from the periphery toward the core) of the electrode assembly 90. At this time, the outermost side 92 of the second portion B3 may not be substantially bent.

[0467] Fig.13 It is a cross-sectional view of a jellyroll-type electrode assembly 100 in which any one of the electrodes 50 , 60 , 70 of the third to fifth embodiments (variations thereof) is applied to a first electrode (positive electrode) and a second electrode (negative electrode), extracted along the Y-axis direction (winding axis direction).

[0468] Reference Fig.13 The first uncoated portion 43a of the first electrode includes a first portion B1 adjacent to the core of the electrode assembly 100, a second portion B3 adjacent to the outer circumferential surface of the electrode assembly 100, and a third portion B2 interposed between the first portion B1 and the second portion B3.

[0469] The height of the first portion B1 is relatively smaller than the height of the third portion B2. In addition, in the third portion B2, the bending length of the innermost uncoated portion 43a is equal to or less than the radial length (R) of the first portion B1. The bending length (H) corresponds to the distance from the point where the uncoated portion 43a is bent to the top of the uncoated portion 43a. In a variation, the bending length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 102.

[0470] Therefore, even if the third portion B2 is bent, more than 90% of the diameter of the core 102 of the electrode assembly 100 is open to the outside. The core 102 is a cavity at the center of the electrode assembly 100. If the core 102 is not blocked, the electrolyte injection process is not difficult and the electrolyte injection efficiency is improved. In addition, by inserting a welding fixture through the core 102, the welding process between the current collector at the negative electrode (or positive electrode) and the battery case (or, terminal) can be easily performed.

[0471] The height of the second portion B3 is relatively smaller than that of the third portion B2. Therefore, when the beaded portion of the battery case is pressed near the second portion B3, an internal short circuit can be prevented from occurring as the beaded portion and the second portion B3 come into contact with each other.

[0472] In a variant, the height of the second portion B3 may be gradually or stepwise reduced, with Fig.13 In addition, Fig.13 , the height of the third portion B2 is the same in the portion near the periphery. However, the height of the third portion B2 may be gradually or stepwise increased from the boundary between the first portion B1 and the third portion B2 toward the boundary between the third portion B2 and the second portion B3. When the third portion B2 is divided into a plurality of segments 61, the region where the height of the uncoated portion 43a varies corresponds to the segment height variable region ( Fig.10a ② in the figure.

[0473] The second non-coating portion 43b has the same structure as the first non-coating portion 43a. In one variation, the second non-coating portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variations).

[0474] Ends 101 of the first and second non-coating portions 43a and 43b may be bent in a radial direction (eg, from the periphery toward the core) of the electrode assembly 100. At this time, the first and second portions B1 and B3 are substantially not bent.

[0475] When the third portion B2 includes a plurality of segments, the bending stress can be relieved to prevent the uncoated portion 43a near the bending point from being torn or abnormally deformed. In addition, when the width and / or height and / or spacing of the segments are adjusted according to the numerical ranges of the above embodiment, the segments are bent toward the core and overlapped with a number of layers sufficient to ensure sufficient welding strength, and no voids (gaps) are formed in the bending surface area.

[0476] Fig.14 is a cross-sectional view of an electrode assembly 110 according to yet another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

[0477] Reference Fig.14 , except that the height of the second portion B3 is substantially equal to the height of the outermost side of the third portion B2, the electrode assembly 110 and Fig. 20 The electrode assemblies 100 have substantially the same configuration.

[0478] The second portion B3 may include a plurality of segments. The configuration of the plurality of segments is substantially the same as that of the fourth embodiment and the fifth embodiment (modification) of the electrode.

[0479] In the electrode assembly 110, the height of the first portion B1 is relatively smaller than the height of the third portion B2. In addition, in the third portion B2, the bending length (H) of the innermost uncoated portion is equal to or smaller than the radial length (R) of the first portion B1. Preferably, the first portion B1 may be a segment skipping region ( Fig.10a ① in FIG. 1 ). In a variation, the bending length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 112 .

[0480] Therefore, even if the third portion B2 is bent, more than 90% of the diameter of the core 112 of the electrode assembly 110 is open to the outside. If the core 112 is not blocked, the electrolyte injection process is not difficult and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 112, the welding process between the current collector at the negative electrode (or positive electrode) and the battery case (or, terminal) can be easily performed.

[0481] In one variation, the structure in which the height of the third portion B2 gradually or stepwise increases from the core toward the periphery may extend to the second portion B3. In this case, the height of the uncoated portion 43a may gradually or stepwise increase from the boundary between the first portion B1 and the third portion B2 toward the outermost surface of the electrode assembly 110.

[0482] The second non-coating portion 43b has the same structure as the first non-coating portion 43a. In a modification, the second non-coating portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (modifications).

[0483] Ends 111 of the first non-coating portion 43a and the second coating portion 43b may be bent in a radial direction (eg, from the periphery toward the core) of the electrode assembly 110. At this time, the first portion B1 is substantially not bent.

[0484] When the third part B2 and the second part B3 include a plurality of segments 61, the bending stress is relieved, so that the uncoated parts 43a, 43b near the bending point can be prevented from being torn or abnormally deformed. In addition, when the width and / or height and / or spacing of the segments are adjusted according to the numerical ranges of the above-mentioned embodiment, the segments are bent toward the core and overlapped by a number of layers sufficient to ensure sufficient welding strength, and no voids (gaps) are formed in the bending surface area.

[0485] Fig.15 2 is a cross-sectional view taken along the Y-axis direction (winding axis direction) of an electrode assembly 120 according to still another embodiment of the present disclosure.

[0486] Reference Fig.15 , the electrode assembly 120 has a pattern in which the height of the third portion B2 gradually or stepwise increases and then decreases. Fig.13 The electrode assembly 100 is substantially the same. The radial region where the height of the second portion B3 changes can be regarded as a segment height variable region ( Fig.10a Even in this case, the variable height region of the segment can be designed so that a region having a uniform number of stacking of segments of 10 or more appears in the bent surface region F formed by bending the second portion B3 within the above-mentioned desired numerical range.

[0487] By adjusting the step pattern included in the third portion B2 (see Figure 6 ) or section (see Figure 7a or Figure 8a )’s height to achieve the change in the height of the third part B2.

[0488] In the electrode assembly 120, the height of the first portion B1 is relatively smaller than the height of the third portion B2. In addition, in the third portion B2, the bending length (H) of the uncoated portion located at the innermost side is equal to or smaller than the radial length (R) of the first portion B1. The area corresponding to the first portion B1 corresponds to a segment skipping area without a segment ( Fig.10a In one variation, the bending length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 122 .

[0489] Therefore, even if the third portion B2 is bent toward the core, more than 90% of the diameter of the core 122 of the electrode assembly 120 is open to the outside. If the core 122 is not blocked, the electrolyte injection process is not difficult and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 122, the welding process can be easily performed between the current collector of the negative electrode (or positive electrode) and the battery case (or, riveted terminal).

[0490] Moreover, the height of the second portion B3 is relatively smaller than the height of the third portion B2, and preferably, no section may be formed in the second portion B3. Therefore, it is possible to prevent the curling portion and the second portion B3 from contacting each other and causing an internal short circuit while the curling portion of the battery case is being pressed near the second portion B3. In a variation, the height of the second portion B3 may be gradually or stepwise reduced toward the periphery.

[0491] The second non-coating portion 43b has the same structure as the first non-coating portion 43a. In one variation, the second non-coating portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variations).

[0492] Ends 121 of the first and second non-coating portions 43a and 43b may be bent toward the core from the outer circumference of the electrode assembly 120. At this time, the first and second portions B1 and B3 are substantially not bent.

[0493] When the third portion B2 includes a plurality of segments, the bending stress is relieved to prevent the uncoated portions 43a, 43b from tearing or abnormally deforming. In addition, when the width and / or height and / or spacing of the segments are adjusted according to the numerical ranges of the above-described embodiment, the segments are bent toward the core and overlapped with a number of layers sufficient to ensure sufficient welding strength, and no voids (gaps) are formed in the bending surface area F.

[0494] Fig.16 is a cross-sectional view illustrating an electrode assembly 130 according to still another embodiment of the present disclosure, taken along the Y-axis direction (winding axis direction).

[0495] Reference Fig.16In addition to the pattern in which the height of the second portion B3 gradually or stepwise decreases from the boundary point between the second portion B3 and the third portion B2 toward the outermost surface of the electrode assembly 130, the electrode assembly 130 and the Fig.15 The electrode assemblies 120 are substantially the same.

[0496] By placing the step pattern (see Figure 6 ) is extended to the second part B3 and the height of the pattern is gradually or stepwise reduced toward the periphery to achieve the height change of the second part B3. In addition, in another variation, the height change of the second part B3 can be achieved by extending the segment structure of the third part B2 to the second part B3 and gradually or stepwise reducing the height of the segment toward the periphery.

[0497] In the electrode assembly 120, the height of the first portion B1 is relatively smaller than the height of the third portion B2. In addition, in the third portion B2, the bending length (H) of the innermost uncoated portion is equal to or smaller than the radial length (R) of the first portion B1. The first portion B1 corresponds to a segment skipping region ( Fig.10a In one variation, the bending length (H) may be less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 132 .

[0498] Therefore, even if the third portion B2 is bent toward the core, more than 90% of the diameter of the core 132 of the electrode assembly 130 is open to the outside. If the core 132 is not blocked, the electrolyte injection process is not difficult and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 132, the welding process can be easily performed between the current collector of the negative electrode (or positive electrode) and the battery case (or, terminal).

[0499] The second non-coating portion 43b has the same structure as the first non-coating portion 43a. In one variation, the second non-coating portion 43b may have a conventional electrode structure or an electrode structure of other embodiments (variations).

[0500] Ends 131 of the first and second non-coating portions 43a and 43b may be bent toward the core from the outer circumference of the electrode assembly 130. At this time, the first portion B1 is substantially not bent.

[0501] When the third part B2 and the second part B3 include a plurality of segments 61, the bending stress is relieved to prevent the uncoated parts 43a, 43b near the bending point from being torn or abnormally deformed. In addition, when the width and / or height and / or spacing of the segments are adjusted according to the numerical ranges of the above-mentioned embodiment, the segments are bent toward the core and overlapped by a number of layers sufficient to ensure sufficient welding strength, and no voids (gaps) are formed in the bending surface area F.

[0502] In addition, in the above embodiment (variation), the ends of the first uncoated portion 43a and the second uncoated portion 43b may be bent from the core toward the periphery. In this case, it is preferred that the second portion B3 is designed as a segment skipping region without a segment ( Fig.10a ①) and does not bend toward the periphery. In addition, the radial width of the second portion B3 may be equal to or greater than the bending length of the outermost uncoated portion (or, segment) of the third portion B2. In this case, when the outermost coated portion (or segment) of the third portion B2 is bent toward the periphery, the end of the bent portion protrudes toward the inner surface of the battery case and does not exceed the periphery of the electrode assembly. In addition, the structural change pattern of the segment may be opposite to that of the above-mentioned embodiment (variation). For example, the height of the segment may increase stepwise or gradually from the periphery toward the core. That is, by arranging the segment skipping areas ( Fig.10a ① in), highly variable regions ( Fig.10a ②) and highly consistent regions ( Fig.10a In ③), in the bending surface area, a region with a consistent stacking number of segments of 10 or more can appear within the desired numerical range.

[0503] Various electrode assembly structures according to embodiments of the present disclosure may be applied to cylindrical batteries.

[0504] Preferably, the cylindrical battery may be, for example, a cylindrical battery having a shape factor ratio (defined as a value obtained by dividing the diameter of a cylindrical battery by the height, i.e., a ratio of the diameter (Φ) to the height (H)) greater than about 0.4. Here, the shape factor refers to a value representing the diameter and height of a cylindrical battery.

[0505] Preferably, the cylindrical battery may have a diameter of 40 mm to 50 mm and a height of 60 mm to 130 mm. The form factor of the cylindrical battery according to an embodiment of the present disclosure may be, for example, 46110, 4875, 48110, 4880, or 4680. In the numerical value representing the form factor, the first two digits represent the diameter of the battery, and the remaining digits represent the height of the battery.

[0506] When an electrode assembly having a jointless structure is applied to a cylindrical battery having a shape factor ratio greater than 0.4, the stress applied in the radial direction when the uncoated portion is bent is large, so that the uncoated portion may be easily torn. In addition, when the current collector is welded to the bent surface area of ​​the uncoated portion, it is necessary to sufficiently increase the number of layers of the uncoated portion in the bent surface area in order to fully ensure the welding strength and reduce the resistance. This requirement can be achieved by an electrode and an electrode assembly according to an embodiment (variation) of the present disclosure.

[0507] The battery according to an embodiment of the present disclosure may be an approximately cylindrical battery having a diameter of about 46 mm, a height of about 110 mm, and a shape factor ratio of 0.418.

[0508] A battery according to another embodiment may be a nearly cylindrical battery having a diameter of about 48 mm, a height of about 75 mm, and an aspect ratio of 0.640.

[0509] A battery according to still another embodiment may be a nearly cylindrical battery having a diameter of about 48 mm, a height of about 110 mm, and a shape factor ratio of 0.436.

[0510] A battery according to still another embodiment may be a nearly cylindrical battery having a diameter of about 48 mm, a height of about 80 mm, and an aspect ratio of 0.600.

[0511] A battery according to still another embodiment may be a nearly cylindrical battery having a diameter of about 46 mm, a height of about 80 mm, and an aspect ratio of 0.575.

[0512] Conventionally, batteries having a form factor ratio of about 0.4 or less have been used. That is, conventionally, for example, 1865 batteries, 2170 batteries, etc. have been used. The 1865 battery has a diameter of about 18 mm, a height of about 65 mm, and a form factor ratio of 0.277. The 2170 battery has a diameter of about 21 mm, a height of about 70 mm, and a form factor ratio of 0.300.

[0513] Hereinafter, a cylindrical battery according to an embodiment of the present disclosure will be described in detail.

[0514] Fig.17 is a cross-sectional view showing a cylindrical battery 140 extracted along the Y-axis direction according to an embodiment of the present disclosure.

[0515] Reference Fig.17 The cylindrical battery 140 according to an embodiment of the present disclosure includes an electrode assembly 141 having a first electrode, a separator, and a second electrode, a battery case 142 for accommodating the electrode assembly 141 , and a sealing body 143 for sealing an open end of the battery case 142 .

[0516] The battery case 142 is a cylindrical container with an opening at the top. The battery case 142 is made of a conductive metal material such as aluminum, steel or stainless steel. A nickel coating layer may be formed on the surface of the battery case 142. The battery case 142 accommodates the electrode assembly 141 in the internal space through the top opening and also accommodates an electrolyte.

[0517] The electrolyte may be a + B- Here, A + Including such as Li + 、Na + or K + alkali metal cation or a combination thereof. And B - comprising at least one anion F selected from the group consisting of - , Cl - Br - ,I - 、NO 3 - 、N(CN) 2 - , BF 4 - , ClO 4 - 、AlO 4 - 、AlCl 4 - PF 6 - , SbF 6 - , AsF 6 - , BF 2 C 2 O 4 - , B.C. 4 O 8 - ,(CF 3 ) 2 PF 4 - ,(CF 3 ) 3 PF 3 - ,(CF 3 ) 4 PF 2 - ,(CF 3 ) 5 PF - ,(CF 3 ) 6 P - CF 3 SO 3 - , C 4 F 9 SO 3 - CF 3 CF 2 SO 3 - ,(CF3 SO 2 ) 2 N - 、(FSO 2 ) 2 N - 、 CF 3 CF 2 (CF 3 ) 2 CO - ,(CF 3 SO 2 ) 2 CH - , (SF 5 ) 3 C - ,(CF 3 SO 2 ) 3 C - CF 3 (CF 2 ) 7 SO 3 - CF 3 CO 2 - , CH 3 CO 2 - 、SCN - and (CF 3 CF 2 SO 2 ) 2 N - .

[0518] The electrolyte may also be dissolved in an organic solvent. The organic solvent may be propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or a mixture thereof.

[0519] The electrode assembly 141 may have a core shape, but the present disclosure is not limited thereto. The electrode assembly 141 may be manufactured by winding a laminate based on a winding axis C, the laminate being formed by sequentially laminating a lower separator, a first electrode, an upper separator, and a second electrode at least once, as shown in FIG. Figure 2 shown.

[0520] The first electrode and the second electrode have different polarities. That is, if one has a positive polarity, the other has a negative polarity. At least one of the first electrode and the second electrode may have an electrode structure according to the above embodiment (variation). In addition, the other electrode of the first electrode and the second electrode may have a conventional electrode structure or an electrode structure according to the embodiment (variation). The electrode pair included in the electrode assembly 141 is not limited to one electrode pair, and may include two or more electrode pairs.

[0521] The first uncoated portion 146a of the first electrode and the second uncoated portion 146b of the second electrode protrude at the upper and lower portions of the electrode assembly 141, respectively. The first electrode has the electrode structure of the first embodiment (modification). Therefore, in the first uncoated portion 146a, the height of the second portion B3 is less than the height of the uncoated portion of other regions. The second portion B3 is spaced apart from the inner periphery of the battery housing 142 (especially the curling portion 147) by a predetermined distance. Therefore, the second portion B3 of the first electrode does not contact the battery housing 142 electrically connected to the second electrode, thereby preventing internal short circuits in the cylindrical battery 140.

[0522] The second non-coating portion 146b of the second electrode may have the same structure as the first non-coating portion 146a. In another modification, the second non-coating portion 146b may selectively have the non-coating portion structure of the electrode according to the embodiment (modification).

[0523] The sealing body 143 may include a cover 143 a having a plate shape, a first gasket 143 b for providing airtightness and insulation between the cover 143 a and the battery case 142 , and a connection plate 143 c electrically and mechanically coupled to the cover 143 a .

[0524] The cover 143a is a member made of a conductive metal material and covers the top opening of the battery case 142. The cover 143a is electrically connected to the uncoated portion 146a of the first electrode and is electrically insulated from the battery case 142 by means of the first gasket 143b. Therefore, the cover 143a can be used as a first electrode (e.g., a positive electrode) of the cylindrical battery 140.

[0525] The cover 143a is placed on the crimping portion 147 formed on the battery case 142 and is fixed by the crimping portion 148. The first gasket 143b may be interposed between the cover 143a and the crimping portion 148 to ensure the airtightness of the battery case 142 and the electrical insulation between the battery case 142 and the cover 143a. The cover 143a may have a protrusion 143d protruding upward from the center thereof.

[0526] The battery case 142 is electrically connected to the second non-coating portion 146b of the second electrode. Therefore, the battery case 142 has the same polarity as the second electrode. If the second electrode has a negative polarity, the battery case 142 also has a negative polarity.

[0527] The battery case 142 includes a curling portion 147 and a pressing portion 148 at the top thereof. The curling portion 147 is formed by press-fitting the periphery of the outer peripheral surface of the battery case 142. The curling portion 147 prevents the electrode assembly 141 accommodated in the battery case 142 from escaping through the top opening of the battery case 142, and can be used as a supporting portion on which the sealing body 143 is placed.

[0528] The inner circumference of the curling portion 147 may be spaced apart from the second portion B3 of the first electrode by a predetermined interval. More specifically, the lower end of the inner circumference of the curling portion 147 is spaced apart from the second portion B3 of the first electrode by a predetermined interval. In addition, since the second portion B3 has a relatively low height, the second portion B3 is substantially unaffected even when the battery case 142 is press-fitted externally to form the curling portion 147. Therefore, the second portion B3 is not pressed by other components such as the curling portion 147, thereby preventing the local shape of the electrode assembly 141 from being deformed, thereby preventing the cylindrical battery 140 from being internally short-circuited.

[0529] Preferably, when the press-fit depth of the curling portion 147 is defined as D1 and the radial length from the inner periphery of the battery case 142 to the boundary point between the second portion B3 and the third portion B2 is defined as D2, the relationship expression D1≤D2 can be satisfied. In this case, when the battery case 142 is press-fitted to form the curling portion 147, damage to the second portion B3 can be substantially prevented.

[0530] The beading portion 148 is formed on the beading portion 147. The beading portion 148 has an extended and bent shape to cover the outer circumference of the cover 143a disposed on the beading portion 147 and a portion of the upper surface of the cover 143a.

[0531] The cylindrical battery 140 may further include a first current collector 144 and / or a second current collector 145 and / or an insulator 146 .

[0532] The first current collector 144 is coupled to the upper portion of the electrode assembly 141. The first current collector 144 is made of a conductive metal material such as aluminum, copper, steel, nickel, etc., and is electrically connected to the uncoated portion 146a of the first electrode. The electrical connection may be made by welding. A lead 149 may be connected to the first current collector 144. The lead 149 may extend upward on the electrode assembly 141 and be coupled to the connection plate 143c or directly to the lower surface of the cover 143a. The lead 149 may be connected to other components by welding.

[0533] Preferably, the first current collector 144 may be integrally formed with the lead 149. In this case, the lead 149 may have an elongated plate shape extending outward from near the center of the first current collector 144.

[0534] The first current collector 144 may have a plurality of irregularities (not shown) radially formed on a lower surface thereof. When the radial irregularities are provided, the irregularities may be press-fitted to the first non-coating portion 146a of the first electrode by pressing the first current collector.

[0535] The first current collector 144 is coupled to the end of the first uncoated portion 146a. The first uncoated portion 146a and the first current collector 144 can be coupled by, for example, laser welding. Laser welding can be performed by locally melting the base material of the first current collector 144. In a variation, the first current collector 144 and the first uncoated portion 146a can be welded with a solder interposed therebetween. In this case, the solder may have a lower melting point than the first current collector 144 and the first uncoated portion 146a. Laser welding may be replaced by resistance welding, ultrasonic welding, spot welding, etc.

[0536] The second current collector 145 may be coupled to the lower surface of the electrode assembly 141. One side of the second current collector 145 may be coupled to the second non-coating portion 146b by welding, and the other side may be coupled to the inner bottom surface of the battery case 142 by welding. The coupling structure between the second current collector 145 and the second non-coating portion 146b may be substantially the same as the coupling structure between the first current collector 144 and the first non-coating portion 146a.

[0537] The non-coating portions 146a, 146b are not limited to the structure shown. Therefore, the non-coating portions 146a, 146b may selectively have a conventional non-coating portion structure and an electrode non-coating portion structure according to an embodiment (variation).

[0538] The insulator 146 may cover the first current collector 144. The insulator 146 may cover the first current collector 144 at an upper surface of the first current collector 144, thereby preventing direct contact between the first current collector 144 and the inner circumference of the battery case 142.

[0539] The insulator 146 has a lead hole 151 so that the lead 149 extending upward from the first current collector 144 can be drawn out through the lead hole 151. The lead 149 is drawn out upward through the lead hole 151 and coupled to the lower surface of the connection plate 143c or the lower surface of the cover 143a.

[0540] The peripheral area of ​​the edge of the insulator 146 may be interposed between the first current collector 144 and the curling portion 147 to fix the coupling body of the electrode assembly 141 and the first current collector 144. Therefore, the movement of the coupling body of the electrode assembly 141 and the first current collector 144 may be restricted in the winding axis direction Y of the cylindrical battery 140, thereby improving the assembly stability of the cylindrical battery 140.

[0541] The insulator 146 may be made of an insulating polymer resin. In one example, the insulator 146 may be made of polyethylene, polypropylene, polyimide, or polybutylene terephthalate.

[0542] The battery case 142 may also include a vent portion 152 formed at its lower surface. The vent portion 152 corresponds to an area having a smaller thickness than the peripheral area of ​​the lower surface of the battery case 142. The vent portion 152 is structurally weaker than the surrounding area. Therefore, when an abnormality occurs in the cylindrical battery 140 and the internal pressure increases to above a predetermined level, the vent portion 152 may rupture, so that the gas generated inside the battery case 142 is discharged to the outside. The internal pressure when the vent portion 152 ruptures may be about 15 kgf / cm 2 Up to 35kgf / cm 2 .

[0543] The vent portion 152 may be formed continuously or discontinuously while drawing a circle at the lower surface of the battery case 142. In one modification, the vent portion 152 may be formed in a straight line pattern or other patterns.

[0544] Fig.18 is a cross-sectional view showing a cylindrical battery 150 extracted along the Y-axis direction according to an embodiment of the present disclosure.

[0545] Reference Fig.18 , except that the electrode structure of the second embodiment (variation) is adopted in the first uncoated portion 146a of the first electrode, the cylindrical battery 150 is similar to Fig.17 The cylindrical batteries 140 have substantially the same configuration.

[0546] Reference Fig.18 , the first uncoated portion 146a of the first electrode may have a shape in which the height of the second portion B3 gradually or stepwise decreases toward the inner circumference of the battery case 142. Preferably, an imaginary line connecting the tops of the second portions B3 may have the same or similar shape as the inner circumference of the curling portion 147.

[0547] The second portion B3 forms an inclined surface. Therefore, when the battery case 142 is press-fitted to form the curling portion 147, the second portion B3 can be prevented from being compressed and damaged by the curling portion 147. In addition, the phenomenon that the second portion B3 contacts the battery case 142 with different polarities and causes an internal short circuit can be suppressed.

[0548] The other configurations of the cylindrical battery 150 are substantially the same as those of the above-described embodiment (modification).

[0549] The non-coating portions 146a, 146b are not limited to the illustrated structure. Therefore, the non-coating portions 146a, 146b may selectively have a conventional non-coating portion structure and an electrode non-coating portion structure according to an embodiment (variation).

[0550] Fig.19 is a cross-sectional view showing a cylindrical battery 160 extracted along the Y-axis direction according to still another embodiment of the present disclosure.

[0551] Reference Fig.19 The cylindrical battery 160 is substantially the same as the above-mentioned cylindrical batteries 140 and 150, except that the lead 149 connected to the first current collector 144 is directly connected to the cover 143a of the sealing body 143 via the lead hole 151 of the insulator 146, and the insulator 146 and the first current collector 144 have a structure in close contact with the lower surface of the cover 143a.

[0552] In the cylindrical battery 160, the diameter of the first current collector 144 and the outermost diameter of the third portion B2 are smaller than the minimum inner diameter of the battery case 142. In addition, the diameter of the first current collector 144 may be equal to or greater than the outermost diameter of the third portion B2.

[0553] Specifically, the minimum inner diameter of the battery case 142 may correspond to the inner diameter of the battery case 142 at the position where the curling portion 147 is formed. At this time, the outermost diameters of the first current collector 144 and the third portion B2 are smaller than the inner diameter of the battery case 142 at the position where the curling portion 147 is formed. In addition, the diameter of the first current collector 144 may be equal to or greater than the outermost diameter of the third portion B2. The peripheral area of ​​the edge of the insulator 146 may be interposed between the second portion B3 and the curling portion 147 in a downwardly bent state to fix the coupling body of the electrode assembly 141 and the first current collector 144.

[0554] Preferably, the insulator 146 includes a portion covering the second portion B3 and a portion covering the first current collector 144, and the portion connecting the two portions may have a curved shape corresponding to the curved shape of the curling portion 147. The insulator 146 may insulate the inner periphery of the second portion B3 and the curling portion 147, and simultaneously insulate the first current collector 144 and the inner periphery of the curling portion 147.

[0555] The first current collector 144 may be positioned higher than the lower end of the curling portion 147 and may be coupled to the first portion B1 and the third portion B2. At this time, the press-fit depth D1 of the curling portion 147 is less than or equal to the distance D2 from the inner periphery of the battery case 142 to the boundary between the second portion B3 and the third portion B2. Therefore, the first portion B1 and the third portion B2 and the first current collector 144 coupled thereto may be positioned higher than the lower end of the curling portion 147. The lower end of the curling portion 147 refers to the bending point B between the portion of the battery case 142 that accommodates the electrode assembly 141 and the curling portion 147.

[0556] Since the first portion B1 and the third portion B2 occupy the inner space of the curling portion 147 in the radial direction, the empty space between the electrode assembly 141 and the cover 143a can be minimized. In addition, the connecting plate 143c located in the empty space between the electrode assembly 141 and the cover 143a is omitted. Therefore, the lead 149 of the first current collector 144 can be directly connected to the lower surface of the cover 143a. According to the above structure, the empty space in the battery is reduced, and the energy density can be maximized as much as the reduced empty space.

[0557] In the cylindrical battery 160 , the first current collector 144 and the second current collector 145 may be welded to the ends of the first non-coating portion 146 a and the second non-coating portion 146 b , respectively, in the same manner as the above embodiment.

[0558] The non-coating portions 146a, 146b are not limited to the structure shown. Therefore, the non-coating portions 146a, 146b may selectively have a conventional non-coating portion structure and an electrode non-coating portion structure according to an embodiment (variation).

[0559] Fig. 20 is a cross-sectional view showing a cylindrical battery 170 extracted along the Y-axis direction according to an embodiment of the present disclosure.

[0560] Reference Fig. 20 The structure of the electrode assembly of the cylindrical battery 170 is similar to Fig.17 The structure of the electrode assembly of the cylindrical battery 140 is basically the same, and other structures except the electrode assembly are changed.

[0561] Specifically, the cylindrical battery 170 includes a battery case 171, through which a terminal 172 is mounted. The terminal 172 is mounted through a through hole formed in a closed surface (upper surface in the figure) of the battery case 171. The terminal 172 is riveted to the through hole of the battery case 171 with a second gasket 173 made of an insulating material interposed therebetween. The terminal 172 is exposed to the outside in a direction opposite to the direction of gravity.

[0562] The 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 case 171. The terminal exposure portion 172a may be located approximately at the center portion of the closed surface of the battery case 171. The maximum diameter portion of the terminal exposure portion 172a may be greater than the maximum diameter of the through hole formed in the battery case 171. The terminal insertion portion 172b may be electrically connected to the uncoated portion 146a of the first electrode through the approximately center portion of the closed surface of the battery case 171. The lower edge of the terminal insertion portion 172b may be riveted on the inner surface of the battery case 171. That is, the lower edge of the terminal insertion portion 172b may have a shape bent toward the inner surface of the battery case 171. A flat portion 172c is included at the inner side of the lower edge of the terminal insertion portion 172b. The maximum diameter of the lower portion of the riveted terminal insertion portion 172b may be greater than the maximum diameter of the through hole of the battery case 171.

[0563] The flat portion 172c of the terminal insertion portion 172b may be welded to the central portion of the first current collector 144 connected to the uncoated portion 146a of the first electrode. Other welding methods such as ultrasonic welding may be used instead of welding.

[0564] An insulator 174 made of an insulating material may be interposed between the first current collector 144 and the inner surface of the battery case 171. The insulator 174 covers the upper portion of the first current collector 144 and the top edge of the electrode assembly 141. Therefore, the second portion B3 of the electrode assembly 141 may be prevented from contacting the inner surface of the battery case 171 having a different polarity and causing a short circuit.

[0565] The thickness of the insulator 174 corresponds to or is slightly greater than the distance between the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery case 171. Therefore, the insulator 174 may contact the upper surface of the first current collector 144 and the inner surface of the closed portion of the battery case 171.

[0566] The terminal insertion portion 172b of the terminal 172 may be welded to the first current collector 144 through the through hole of the insulator 174. The diameter of the through hole formed in the insulator 174 may be greater than the diameter of the riveted portion at the lower end of the terminal insertion portion 172b. Preferably, the through hole may expose the lower portion of the terminal insertion portion 172b and the second gasket 173.

[0567] The second gasket 173 is interposed between the battery case 171 and the terminal 172 to prevent the battery case 171 and the terminal 172 having opposite polarities from electrically contacting each other. Therefore, the upper surface of the battery case 171 having a substantially flat shape can be used as a second electrode (e.g., a negative electrode) of the cylindrical battery 170.

[0568] The second gasket 173 includes a gasket exposed portion 173a and a gasket inserted portion 173b. The gasket exposed portion 173a is inserted between the terminal exposed portion 172a of the riveted terminal 172 and the battery case 171. The gasket inserted portion 173b is inserted between the terminal inserted portion 172b of the riveted terminal 172 and the battery case 171. When the terminal inserted portion 172b is riveted, the gasket inserted portion 173b can be deformed together so as to be in close contact with the inner surface of the battery case 171. The second gasket 173 can be made of, for example, a polymer resin having an insulating property.

[0569] The gasket exposed portion 173a of the second gasket 173 may have an extended shape to cover the outer periphery of the terminal exposed portion 172a of the riveted terminal 172. When the second gasket 173 covers the outer periphery of the riveted terminal 172, a short circuit may be prevented from occurring while an electrical connection component such as a bus bar is coupled to the upper surface of the battery case 171 and / or the riveted terminal 172. Although not shown in the drawings, the gasket exposed portion 173a may have an extended shape to cover not only the outer periphery of the terminal exposed portion 172a but also a portion of the upper surface thereof.

[0570] When the second gasket 173 is made of a polymer resin, the second gasket 173 may be coupled to the battery case 171 and the terminal 172 by thermal fusion. In this case, the airtightness at the coupling interface between the second gasket 173 and the terminal 172 and the coupling interface between the second gasket 173 and the battery case 171 may be enhanced. In addition, when the gasket exposed portion 173a of the second gasket 173 has a shape extending to the upper surface of the terminal exposed portion 172a, the terminal 172 may be integrally coupled to the second gasket 173 by insert injection molding.

[0571] In the upper surface of the battery case 171 , the remaining area 175 excluding the area occupied by the terminal 172 and the second gasket 173 corresponds to a second electrode terminal having a polarity opposite to that of the terminal 172 .

[0572] The second current collector 176 is coupled to the lower portion of the electrode assembly 141. The second current collector 176 is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected to the second non-coating portion 146b of the second electrode.

[0573] Preferably, the second current collector 176 is electrically connected to the battery housing 171. To this end, at least a portion of the edge of the second current collector 176 may be inserted and fixed between the inner surface of the battery housing 171 and the first gasket 178b. In one example, at least a portion of the edge of the second current collector 176 may be fixed to the curling portion 180 by welding while being supported on the lower surface of the curling portion 180 formed at the bottom of the battery housing 171. In a variation, at least a portion of the edge of the second current collector 176 may be directly welded to the inner wall surface of the battery housing 171.

[0574] The second current collector 176 may include a plurality of irregularities (not shown) radially formed on a surface facing the second non-coating portion 146 b . When the irregularities are formed, the irregularities may be press-fitted into the second non-coating portion 146 b by pressing the second current collector 176 .

[0575] Preferably, the second current collector 176 and the second uncoated portion 146b may be coupled by welding (eg, laser welding). In addition, the welding region of the second current collector 176 and the second uncoated portion 146b may be spaced apart by a predetermined interval toward the core C based on the inner circumference of the curling portion 180.

[0576] The sealing body 178 for sealing the lower open end of the battery housing 171 includes a cover 178a having a plate shape and a first gasket 178b. The first gasket 178b electrically separates the cover 178a from the battery housing 171. The edge pressing portion 181 fixes the edge of the cover 178a and the first gasket 178b together. The cover 178a has a venting portion 179. The construction of the venting portion 179 is substantially the same as the above embodiment (variation). The lower surface of the cover 178a may be located above the lower end of the edge pressing portion 181. In this case, a space is formed below the cover 178a to smoothly perform venting. Specifically, it is useful to make the edge pressing portion 181 face the direction of gravity when the cylindrical battery 170 is installed.

[0577] Preferably, the cover 178a is made of a conductive metal material. However, since the first gasket 178b is interposed between the cover 178a and the battery case 171, the cover 178a does not have an electrical polarity. The seal 178 seals the open end of the lower portion of the battery case 171 and is mainly used to discharge gas when the internal pressure of the cylindrical battery 170 increases beyond a critical value. The threshold value of the pressure is 15kgf / cm 2 Up to 35kgf / cm2 .

[0578] Preferably, the terminal 172 electrically connected to the first uncoated portion 146a of the first electrode is used as the first electrode terminal. In addition, in the upper surface of the battery case 171 electrically connected to the second uncoated portion 146b of the second electrode by the second current collector 176, the portion 175 other than the terminal 172 is used as a second electrode terminal having a different polarity from the first electrode terminal. If the two electrode terminals are located at the upper part of the cylindrical battery 170 as described above, electrical connection components such as bus bars can be arranged only on one side of the cylindrical battery 170. This can simplify the battery pack structure and improve the energy density. In addition, since the portion 175 used as the second electrode terminal has a substantially flat shape, a sufficient connection area can be ensured for connecting electrical connection components such as bus bars. Therefore, the cylindrical battery 170 can reduce the resistance at the connection portion of the electrical connection component to a desired level.

[0579] Meanwhile, the structure of the electrode assembly 141 and the structure of the non-coating portion are not limited to those shown, and may be replaced with the structures of the above-described embodiments (modifications).

[0580] Fig.21 is a cross-sectional view showing a cylindrical battery 180 extracted along the Y-axis direction according to still another embodiment of the present disclosure.

[0581] Reference Fig.21 , the electrode assembly 141 of the cylindrical battery 180 and Fig.18 The cylindrical battery 150 shown has substantially the same structure and is similar in configuration to the battery 150 except for the electrode assembly 141. Fig. 20 The structure of the cylindrical batteries 170 shown is basically the same.

[0582] Therefore, the configurations of the embodiments (variations) of the cylindrical batteries 150 , 170 may be equally applied to the cylindrical battery 180 .

[0583] In addition, the structure of the electrode assembly 141 and the structure of the non-coating portion are not limited to those shown, and may be replaced with the structures of the above-described embodiment (modification).

[0584] Fig. 22 is a cross-sectional view showing a cylindrical battery 190 extracted along the Y-axis direction according to still another embodiment of the present disclosure.

[0585] Reference Fig. 22 , the cylindrical battery 190 includes Fig.14 The electrode assembly 110 shown in FIG. 1 and other structures other than the electrode assembly 110 are similar to Fig.17 The cylindrical battery 140 shown is substantially the same in construction. Figures 14 to 17 The described configuration can be basically equally applied to this embodiment.

[0586] Reference Fig.10a and Fig. 22 The first and second uncoated portions 146a and 146b of the electrode assembly 110 are bent in a radial direction of the electrode assembly 110 (eg, from the periphery toward the core) to form a bent surface region F.

[0587] The first portion B1 has a lower height than the other portions and corresponds to the segment-free segment skipping region a1 , so it is not bent toward the core.

[0588] Preferably, from the core toward the periphery, the bending surface region F may include a segment skipping region a1, a segment height variable region a2, and a segment height uniform region a3.

[0589] like Fig.10c , Fig.10d and Fig.10e As shown, the bending surface region F includes a stacking number uniform region b1 having a stacking number of 10 or more adjacent to the segment skipping region a1.

[0590] The bent surface region F may further include a stacking number reduction region b2 adjacent to the outer periphery of the electrode assembly 110, wherein the stacking number of the segments decreases toward the outer periphery. Preferably, the stacking number uniform region b1 may be set as a welding target region.

[0591] In the bending surface area F, the preferred numerical ranges of the ratio of the segment height variable area a2 to the radial area c containing the segment (a2 / c), the ratio of the stacking number consistent area b1 to the radial area c containing the segment (b1 / c), and the ratio of the area of ​​the stacking number consistent area b1 to the area of ​​the bending surface area F have been described above and will not be described again.

[0592] The first current collector 144 may be laser welded to the bent surface region F of the first uncoated portion 146a, and the second current collector 145 may be laser welded to the bent surface region F of the second uncoated portion 146b. The welding method may be replaced by ultrasonic welding, resistance welding, spot welding, etc. The welding region W between the second current collector 176 and the second uncoated portion 146b may be spaced apart from the inner surface of the curling portion 180 by a predetermined interval.

[0593] Preferably, more than 50% of the area of ​​the welding region W of the first current collector 144 and the second current collector 145 may overlap with the stacking number consistent region b1 of the bending surface region F. Optionally, the remaining area of ​​the welding region W may overlap with the stacking number reduced region b2 of the bending surface region F. In terms of high welding strength, low resistance of the welding interface, and prevention of damage to the separator or active material layer, it is more advantageous that the entire welding region W overlaps with the stacking number consistent region b1.

[0594] Preferably, the stacking number of the segments may be 10 to 35 in the stacking number uniform region b1 overlapping the welding region W and the optional stacking number reduced region b2.

[0595] Alternatively, when the number of stacking sections of the stacking number reduction region b2 overlapping the welding region W is less than 10, the laser output for welding the stacking number reduction region b2 may be lower than the laser output for welding the stacking number uniform region b1. That is, when the welding region W overlaps the stacking number uniform region b1 and the stacking number reduction region b2 at the same time, the laser output may vary according to the stacking number of the sections. In this case, the welding strength of the stacking number uniform region b1 may be greater than the welding strength of the stacking number reduced region b2.

[0596] In the bent surface regions F formed on the upper and lower portions of the electrode assembly 110 , radial lengths of the segment skipping region a1 and / or the segment height variable region a2 and / or the segment height uniform region a3 may be the same or different.

[0597] In the electrode assembly 110, the first portion B1 has a relatively smaller height than other portions. Fig.14 As shown, the bending length (H) of the innermost uncoated portion is less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 112 .

[0598] Therefore, even if the first uncoated portion 146a is bent toward the core, more than 90% of the diameter of the core 112 of the electrode assembly 110 can be opened to the outside. If the core 112 is not blocked, the electrolyte injection process is not difficult and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 112, the welding process can be easily performed between the second current collector 145 and the battery case 142.

[0599] In the case where the uncoated portions 146a, 146b have a segmented structure, if the width and / or height and / or spacing of the segments are adjusted to meet the numerical range of the above embodiment, when the segments are bent, the segments overlap by several layers sufficient to ensure sufficient welding strength, and no voids (gaps) are formed in the bending surface area F.

[0600] Preferably, the first current collector 144 and the second current collector 145 may have segments 61, 61′ ( Fig.10f ) of the end portion. In this case, the welding can be performed in a state where the segments forming the bent surface area F are uniformly pressed by the current collector, and the tightly stacked state of the segments can be well maintained even after welding. The tightly stacked state refers to the state in which Fig.10a The state shown has substantially no gaps between the segments. The tightly stacked state helps reduce the resistance of the cylindrical battery 190 to a level suitable for fast charging (eg, 4 milliohms) or less.

[0601] The structure of the non-coating portions 146a, 146b may be changed to the structure according to the above embodiment (modification). In addition, a conventional non-coating portion structure may be applied to any one of the non-coating portions 146a, 146b without limitation.

[0602] When the cutout portion 62 ( Figure 7i to Figure 7n ), even if stress greater than or equal to the threshold is applied to the segments 61, 61' welded to the first and second current collectors 144 and 145 due to vibration or expansion of the electrode assembly 110, the stress is released by rupture of the cutout portion 62 near the welding area. Therefore, it is possible to prevent an internal short circuit from occurring due to active material fragments generated when the uncoated portions 146a, 146b and the active material portion are torn together due to stress.

[0603] Fig.23 is a cross-sectional view showing a cylindrical battery 200 according to still another embodiment of the present disclosure, taken along the Y-axis direction.

[0604] Reference Fig.23 , the cylindrical battery 200 includes Fig.14 The electrode assembly 110 shown in FIG. 1 and other structures other than the electrode assembly 110 are similar to Fig.21 The cylindrical battery 180 shown is substantially the same in construction. Fig.14 and Fig.21 The described configuration can be basically equally applied to this embodiment.

[0605] like Fig.10a and Fig.23 As shown, the first and second uncoated portions 146 a and 146 b of the electrode assembly 110 are bent in a radial direction of the electrode assembly 110 (eg, from the periphery toward the core) to form a bent surface region F. As shown in FIG.

[0606] The first portion B1 has a lower height than the other portions and corresponds to the segment-free segment skipping region a1, so it is not bent toward the core.

[0607] Preferably, from the core toward the periphery, the bending surface region F may include a segment skipping region a1, a segment height variable region a2, and a segment height uniform region a3.

[0608] like Fig.10c , Fig.10d and Fig.10e As shown, the bending surface region F includes a stacking number uniform region b1 having a stacking number of 10 or more adjacent to the segment skipping region a1.

[0609] The bent surface region F may further include a stacking number reduction region b2 adjacent to the outer periphery of the electrode assembly 110, wherein the stacking number of the segments decreases toward the outer periphery. Preferably, the stacking number uniform region b1 may be set as a welding target region.

[0610] In the bending surface area F, the preferred numerical ranges of the ratio of the segment height variable area a2 to the radial area c containing the segment (a2 / c), the ratio of the segment stacking number consistent area b1 to the radial area c containing the segment (b1 / c), and the ratio of the area of ​​the stacking number consistent area b1 to the area of ​​the bending surface area F have been described above and will not be described again.

[0611] The first current collector 144 may be laser welded to the bent surface region F of the first uncoated portion 146a, and the second current collector 145 may be laser welded to the bent surface region F of the second uncoated portion 146b. The welding method may be replaced by ultrasonic welding, resistance welding, spot welding, etc. The welding region W between the second current collector 176 and the second uncoated portion 146b may be spaced apart from the inner surface of the curling portion 180 by a predetermined interval.

[0612] Preferably, more than 50% of the area of ​​the welding region W of the first current collector 144 and the second current collector 145 may overlap with the stacking number consistent region b1 of the bending surface region F. Optionally, the remaining area of ​​the welding region W may overlap with the stacking number reduced region b2 of the bending surface region F. In terms of high welding strength, low resistance of the welding interface, and prevention of damage to the separator or active material layer, it is more advantageous that the entire welding region W overlaps with the stacking number consistent region b1.

[0613] Preferably, the stacking number of the segments may be 10 to 35 in the stacking number uniform region b1 overlapping the welding region W and the optional stacking number reduced region b2.

[0614] Alternatively, when the number of stacking sections of the stacking number reduction region b2 overlapping the welding region W is less than 10, the laser output for welding the stacking number reduction region b2 may be lower than the laser output for welding the stacking number uniform region b1. That is, when the welding region W overlaps the stacking number uniform region b1 and the stacking number reduction region b2 at the same time, the laser output may vary according to the stacking number of the sections. In this case, the welding strength of the stacking number uniform region b1 may be greater than the welding strength of the stacking number reduced region b2.

[0615] In the bent surface regions F formed on the upper and lower portions of the electrode assembly 110 , radial lengths of the segment skipping region a1 and / or the segment height variable region a2 and / or the segment height uniform region a3 may be the same or different.

[0616] In the electrode assembly 110, the first portion B1 has a relatively smaller height than other portions. Fig.14 As shown, the bending length (H) of the innermost segment is less than the sum of the radial length (R) of the first portion B1 and 10% of the radius of the core 112 .

[0617] Therefore, even if the first uncoated portion 146a is bent toward the core, more than 90% of the diameter of the core 112 of the electrode assembly 110 can be opened to the outside. If the core 112 is not blocked, the electrolyte injection process is not difficult and the electrolyte injection efficiency is improved. In addition, by inserting a welding jig through the core 112, the welding process can be easily performed between the first current collector 144 and the terminal 172.

[0618] In the case where the uncoated portions 146a, 146b have a segmented structure, if the width and / or height and / or spacing of the segments are adjusted to meet the numerical range of the above embodiment, when the segments are bent, the segments overlap by several layers sufficient to ensure sufficient welding strength, and no voids (gaps) are formed in the bending surface area F.

[0619] Preferably, the regions of the first current collector 144 and the second current collector 176 that are in contact with the first uncoated portion 146a and the second uncoated portion 146b may have segments 61, 61′ ( Fig.10f ) of the end portion. In this case, the welding can be performed in a state where the segments forming the bent surface area F are uniformly pressed by the current collector, and the tightly stacked state of the segments can be well maintained even after welding. The tightly stacked state refers to the state in which Fig.10a The state shown has substantially no gaps between the segments. The tightly stacked state helps reduce the resistance of the cylindrical battery 200 to a level suitable for fast charging (eg, 4 milliohms) or less.

[0620] The structure of the non-coating portions 146a, 146b may be changed to the structure according to the above embodiment (modification). In addition, a conventional non-coating portion structure may be applied to any one of the non-coating portions 146a, 146b without limitation.

[0621] When the cutout portion 62 ( Figure 7i to Figure 7n ), even if stress greater than or equal to the threshold is applied to the segments 61, 61' welded to the first current collector 144 and the second current collector 176 due to vibration or expansion of the electrode assembly 110, the stress is released by rupture of the cutout portion 62 near the welding area. Therefore, it is possible to prevent an internal short circuit from occurring due to active material fragments generated when the uncoated portions 146a, 146b and the active material portion are torn together due to stress.

[0622] Fig.24 2 is a cross-sectional view showing a cylindrical battery 210 extracted along the Y-axis direction according to an embodiment of the present disclosure.

[0623] Reference Fig.24 , the cylindrical battery 210 includes Fig.13 The electrode assembly 100 shown in FIG. 1 and other components except the electrode assembly 100 are similar to Fig.17 The components of the cylindrical battery 140 shown are substantially the same. Fig.13 and Fig.17 The described configuration can be basically equally applied to this embodiment.

[0624] Preferably, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 100 are divided into a plurality of segments, and the segments are bent in the radial direction of the electrode assembly 110 (e.g., from the periphery toward the core). At this time, since the first portion B1 and the second portion B3 of the first uncoated portion 146a have a lower height than other portions and do not include a segment, they are substantially not bent. The same is true in the case of the second uncoated portion 146b.

[0625] In addition, in this embodiment, from the core toward the periphery, the bending surface area F may include a segment skipping area a1, a segment height variable area a2, and a segment height uniform area a3. However, since the second portion B3 is not bent, the radial length of the bending surface area F may be shorter than in the above embodiment.

[0626] like Fig.10c , Fig.10d and Fig.10eAs shown, the bending surface region F includes a stacking number uniform region b1 having a stacking number of 10 or more adjacent to the segment skipping region a1.

[0627] The bent surface region F may further include a stacking number reduction region b2 adjacent to the second portion B3 of the electrode assembly 100, in which the stacking number of the segments decreases toward the periphery. Preferably, the stacking number uniform region b1 may be set as a welding target region.

[0628] In the bending surface area F, the preferred numerical ranges of the ratio of the segment height variable area a2 to the radial area c containing the segment (a2 / c), the ratio of the segment stacking number consistent area b1 to the radial area c containing the segment (b1 / c), and the ratio of the area of ​​the stacking number consistent area b1 to the area of ​​the bending surface area F have been described above and will not be described again.

[0629] The first current collector 144 may be welded to the bent surface region F of the first non-coating portion 146 a , and the second current collector 145 may be welded to the bent surface region F of the second non-coating portion 146 b .

[0630] The overlapping relationship between the lamination number uniform region b1 and the lamination number reduced region b2 and the welding region W, the outer diameters of the first current collector 144 and the second current collector 145, and the configuration that the first portion B1 does not block more than 10% of the core diameter are substantially the same as described above.

[0631] In addition, the second portion B3 does not include a section, and the height of the second portion B3 is lower than the height of the third portion B2. Therefore, when the first uncoated portion 146a is bent, the second portion B3 is substantially not bent. In addition, since the second portion B3 is sufficiently spaced apart from the curling portion 147, the problem of damaging the second portion B3 can be solved while press-fitting the curling portion 147.

[0632] The structure of the non-coating portions 146a, 146b may be changed to the structure according to the above embodiment (modification). In addition, a conventional non-coating portion structure may be applied to any one of the non-coating portions 146a, 146b without limitation.

[0633] When the cutout portion 62 ( Figure 7i to Figure 7n), even if stress greater than or equal to the threshold is applied to the segments 61, 61' welded to the first and second current collectors 144 and 145 due to vibration or expansion of the electrode assembly 100, the stress is released by rupture of the cutout portion 62 near the welding area. Therefore, it is possible to prevent an internal short circuit from occurring due to active material fragments generated when the uncoated portions 146a, 146b and the active material portion are torn together due to stress.

[0634] Fig.25 is a cross-sectional view showing a cylindrical battery 220 extracted along the Y-axis direction according to still another embodiment of the present disclosure.

[0635] Reference Fig.25 , the cylindrical battery 220 includes Fig.24 The electrode assembly 100 shown in FIG. 1 and other structures other than the electrode assembly 100 are Fig.21 The cylindrical battery 180 shown is substantially the same in construction. Fig.21 and Fig.24 The described configuration can be basically equally applied to this embodiment.

[0636] Preferably, the first uncoated portion 146a and the second uncoated portion 146b of the electrode assembly 100 are divided into a plurality of sections and bent from the periphery toward the core. At this time, since the first portion B1 and the second portion B3 of the first uncoated portion 146a have a lower height than other portions and do not include sections, they are substantially not bent. The same is true in the case of the second uncoated portion 146b.

[0637] Therefore, in this embodiment, Fig.24 Similar to the embodiment of the present invention, from the core toward the periphery, the bending surface area F may include a segment skipping area a1, a segment height variable area a2 and a segment height uniform area a3. However, since the second portion B3 is not bent, the radial length of the bending surface area F may be shorter than in the case of the above embodiment.

[0638] like Fig.10c , Fig.10d and Fig.10e As shown, the bending surface region F includes a stacking number uniform region b1 having a stacking number of 10 or more adjacent to the segment skipping region a1.

[0639] The bent surface region F may further include a stacking number reduction region b2 adjacent to the second portion B3 of the electrode assembly 110, wherein the stacking number of the segments decreases toward the periphery. Preferably, the stacking number uniform region b1 may be set as a welding target region.

[0640] In the bending surface area F, the preferred numerical ranges of the ratio of the segment height variable area a2 to the radial area c containing the segment (a2 / c), the ratio of the segment stacking number consistent area b1 to the radial area c containing the segment (b1 / c), and the ratio of the area of ​​the stacking number consistent area b1 to the area of ​​the bending surface area F have been described above and will not be described again.

[0641] The first current collector 144 may be welded to the bent surface region F of the first non-coating portion 146 a , and the second current collector 176 may be welded to the bent surface region F of the second non-coating portion 146 b .

[0642] The overlapping relationship between the lamination number uniform region b1 and the lamination number reduced region b2 and the welding region W, the outer diameters of the first current collector 144 and the second current collector 176, and the configuration that the first portion B1 does not block more than 10% of the core diameter are substantially the same as described above.

[0643] The structure of the non-coating portions 146a, 146b may be changed to the structure according to the above embodiment (modification). In addition, a conventional non-coating portion structure may be applied to any one of the non-coating portions 146a, 146b without limitation.

[0644] In an embodiment (variation), the first current collector 144 and the second current collector 176 included in the cylindrical battery 170, 180, 200, 220 including the terminal 172 may have a Fig.26 and Fig. 27 The improved structure shown.

[0645] The improved structure of the first current collector 144 and the second current collector 176 can help reduce the resistance of the cylindrical battery, improve vibration resistance, and improve energy density. Specifically, the first current collector 144 and the second current collector 176 are more effective when used for large cylindrical batteries with a diameter to height ratio greater than 0.4.

[0646] When the cutout portion 62 ( Figure 7i to Figure 7n ), even if stress greater than or equal to the threshold is applied to the segments 61, 61' welded to the first current collector 144 and the second current collector 176 due to vibration or expansion of the electrode assembly 100, the stress is released by rupture of the cutout portion 62 near the welding area. Therefore, it is possible to prevent an internal short circuit from occurring due to active material fragments generated when the uncoated portions 146a, 146b and the active material portion are torn together due to stress.

[0647] Fig.26 is a top plan view showing the structure of the first current collector 144 according to an embodiment of the present disclosure.

[0648] Refer to Fig.23 and Fig.26 , the first current collector 144 may include an edge portion 144a, a first uncoated portion coupling portion 144b, and a terminal coupling portion 144c. The edge portion 144a is disposed on the electrode assembly 100. The edge portion 144a may have an empty space (S open ) is substantially a flange shape. In the drawings of the present disclosure, only the case where the edge portion 144a has a substantially circular flange shape is illustrated, but the present disclosure is not limited thereto. Different from what is illustrated, the edge portion 144a may have a substantially rectangular flange shape, a hexagonal flange shape, an octagonal flange shape, or other flange shapes. The number of edge portions 144a may be increased to two or more. In this case, another edge portion in the form of a flange may be included within the edge portion 144a.

[0649] The terminal coupling portion 144 c may have a diameter equal to or greater than a diameter of a flat portion 172 c formed on the bottom surface of the terminal 172 to ensure a welding area for coupling with the flat portion 172 c formed on the bottom surface of the terminal 172 .

[0650] The first uncoated portion coupling portion 144b extends inwardly from the edge portion 144a and is coupled to the uncoated portion 146a by welding. The terminal coupling portion 144c is spaced apart from the first uncoated portion coupling portion 144b and is located inside the edge portion 144a. The terminal coupling portion 144c may be coupled to the terminal 172 by welding. The terminal coupling portion 144c may be located, for example, in an inner space (S ) surrounded by the edge portion 144a. open ). The terminal connection portion 144c may be disposed at a position corresponding to a hole formed in the core C of the electrode assembly 110. The terminal connection portion 144c may be configured to cover the hole formed in the core C of the electrode assembly 110 so that the hole formed in the core C of the electrode assembly 100 is not exposed from the terminal connection portion 144c. To this end, the terminal connection portion 144c may have a larger diameter or width than the hole formed in the core C of the electrode assembly 110.

[0651] The first uncoated portion connecting portion 144b and the terminal connecting portion 144c may not be directly connected, but may be arranged to be spaced apart from each other and indirectly connected through the edge portion 144a. Since the first current collector 144 has the following structure: the first uncoated portion connecting portion 144b and the terminal connecting portion 144c are not directly connected to each other but are connected through the edge portion 144a as above, when shock and / or vibration occurs in the cylindrical battery 200, the shock applied to the connecting portion between the first uncoated portion connecting portion 144b and the first uncoated portion 146a and the connecting portion between the terminal connecting portion 144c and the terminal 172 can be dispersed. In the drawings of the present disclosure, only the case where four first uncoated portion connecting portions 144b are provided is illustrated, but the present disclosure is not limited thereto. According to the shape complexity, resistance, and the internal space (S ) inside the edge portion 144a where the electrolyte is impregnated, open ) etc., the number of the first uncoated portion coupling portions 144b may be determined in various ways taking into account manufacturing difficulty.

[0652] The first current collector 144 may also include a bridge portion 144d extending inwardly from the edge portion 144a and connected to the terminal coupling portion 144c. Compared with the first uncoated portion coupling portion 144b and the edge portion 144a, at least a portion of the bridge portion 144d may have a smaller cross-sectional area. For example, at least a portion of the bridge portion 144d may be formed to have a smaller width and / or thickness than the first uncoated portion coupling portion 144b. In this case, the resistance in the bridge portion 144d increases. Therefore, when current flows through the bridge portion 144d, a relatively large resistance causes a portion of the bridge portion 144d to melt due to overcurrent heating. Therefore, the overcurrent is irreversibly blocked. The cross-sectional area of ​​the bridge portion 144d can be adjusted to an appropriate level in view of the overcurrent blocking function.

[0653] The bridge portion 144d may include a tapered portion 144e whose width gradually decreases from the inner surface of the edge portion 144a toward the terminal coupling portion 144c. When the tapered portion 144e is provided, the rigidity of the component can be improved at the connection portion between the bridge portion 144d and the edge portion 144a. When the tapered portion 144e is provided, in the process of manufacturing the cylindrical battery 200, for example, a conveying device and / or a worker can easily and safely convey the first current collector 144 and / or the first current collector 144 and the coupling body of the electrode assembly 110 by gripping the tapered portion 144e. That is, when the tapered portion 144e is provided, product defects that may occur by gripping a portion that is welded together with other components such as the first uncoated portion coupling portion 144b and the terminal coupling portion 144c can be prevented.

[0654] The first uncoated portion coupling portion 144b may be provided in plurality. A plurality of first uncoated portion coupling portions 144b may be provided at regular intervals from each other in the extension direction of the edge portion 144a. The extension lengths of each of the plurality of first uncoated portion coupling portions 144b may be substantially equal to each other. The first uncoated portion coupling portion 144b may be coupled to the bending surface region F of the uncoated portion 146a by laser welding. Welding may be replaced by ultrasonic welding, spot welding, etc.

[0655] The welding pattern 144f formed by welding between the first non-coating portion coupling portion 144b and the bent surface region F may have a structure extending in a radial direction of the electrode assembly 110. The welding pattern 144f may be an array of line patterns or dot patterns.

[0656] The welding pattern 144f corresponds to the welding area. Therefore, it is desirable that the welding pattern 144f overlaps the stacking number consistent area b1 of the bending surface area F by more than 50%. The welding pattern 144f that does not overlap the stacking number consistent area b1 may overlap the stacking number reduced area b2. More preferably, the entire welding pattern 144f may overlap the stacking number consistent area b1 of the bending surface area F. In the bending surface area F below the point where the welding pattern 144f is formed, the stacking number consistent area b1 and the optional stacking number reduced area b2 preferably have a stacking number of 10 or more.

[0657] The terminal coupling portion 144c may be arranged to be surrounded by a plurality of first uncoated portion coupling portions 144b. The terminal coupling portion 144c may be coupled to the flat portion 172c of the terminal 172 by welding. The bridge portion 144d may be located between a pair of first uncoated portion coupling portions 144b adjacent to each other. In this case, the distance from the bridge portion 144d to any one of a pair of first uncoated portion coupling portions 144b along the extension direction of the edge portion 144a may be substantially equal to the distance from the bridge portion 144d to another of a pair of first uncoated portion coupling portions 144b along the extension direction of the edge portion 144a. A plurality of first uncoated portion coupling portions 144b may be formed to have substantially the same cross-sectional area. A plurality of first uncoated portion coupling portions 144b may be formed to have substantially the same width and thickness.

[0658] Although not shown in the drawings, the bridge portion 144d may be provided in plurality. Each of the plurality of bridge portions 144d may be provided between a pair of first uncoated portion coupling portions 144b adjacent to each other. The plurality of bridge portions 144d may be provided at substantially regular intervals from each other in the extension direction of the edge portion 144a. The distance from each of the plurality of bridge portions 144d to one of a pair of first uncoated portion coupling portions 144b adjacent to each other along the extension direction of the edge portion 144a may be substantially equal to the distance from each of the plurality of bridge portions 144d to another first uncoated portion coupling portion 144b.

[0659] In the case where the first uncoated portion connecting portion 144b and / or the bridge portion 144d are set in plurality as described above, if the distance between the first uncoated portion connecting portions 144b and / or the distance between the bridge portions 144d and / or the distance between the first uncoated portion connecting portions 144b and the bridge portion 144d are formed to be consistent, current flowing from the first uncoated portion connecting portion 144b to the bridge portion 144d or current flowing from the bridge portion 144d to the first uncoated portion connecting portion 144b can be smoothly formed.

[0660] The bridge portion 144d may include a cutout portion N formed to partially reduce the cross-sectional area of ​​the bridge portion 144d. For example, the cross-sectional area of ​​the cutout portion N may be adjusted by partially reducing the width and / or thickness of the bridge portion 144d. When the cutout portion N is provided, the resistance in the region where the cutout portion N is formed increases, thereby being able to quickly cut off the current when an overcurrent occurs.

[0661] The cutout portion N is preferably disposed in an area corresponding to an area where the number of layers of the electrode assembly 100 is consistent in order to prevent foreign matter generated during rupture from flowing into the electrode assembly 100. This is because, in this area, the number of overlapping layers of the section of the uncoated portion 146a is kept at a maximum, and thus the overlapping section can be used as a shield.

[0662] The cutout portion N may be wrapped with an insulating tape. Then, since the heat generated in the cutout portion N is not dissipated to the outside, when an overcurrent flows through the bridge portion 144d, the cutout portion N may be broken more quickly.

[0663] Fig. 27 is a top plan view showing the structure of the second current collector 176 according to an embodiment of the present disclosure.

[0664] Refer to Fig.23 and Fig. 27, the second current collector 176 is disposed below the electrode assembly 110. In addition, the second current collector 176 may be configured to electrically connect the uncoated portion 146b of the electrode assembly 110 and the battery case 171. The second current collector 176 is made of a conductive metal material and is electrically connected to the bent surface area F of the uncoated portion 146b. In addition, the second current collector 176 is electrically connected to the battery case 171. The edge portion of the second current collector 176 may be inserted and fixed between the inner surface of the battery case 171 and the first gasket 178b. Specifically, the edge portion of the second current collector 176 may be inserted between the lower surface of the curling portion 180 of the battery case 171 and the first gasket 178b. However, the present disclosure is not limited thereto, and the edge portion of the second current collector 176 may be welded to the inner wall surface of the battery case 171 in an area where the curling portion 180 is not formed.

[0665] The second current collector 176 may include a support portion 176a disposed below the electrode assembly 110, a second non-coating portion coupling portion 176b extending from the support portion 176a substantially along the radial direction of the electrode assembly 110 and coupled to the bent surface area F of the non-coating portion 146b, and a housing coupling portion 176c extending from the support portion 176a toward the inner surface of the battery case 171 substantially along an inclined direction based on the radial direction of the electrode assembly 110 and coupled to the inner surface of the battery case 171. The second non-coating portion coupling portion 176b and the housing coupling portion 176c are indirectly connected through the support portion 176a and are not directly connected to each other. Therefore, when an external impact is applied to the cylindrical battery 200 of the present disclosure, the possibility of damage to the coupling portion of the second current collector 176 and the electrode assembly 110 and the coupling portion of the second current collector 176 and the battery case 171 can be minimized. However, the second current collector 176 of the present disclosure is not limited to a structure in which the second non-coating portion coupling portion 176b and the housing coupling portion 176c are only indirectly connected. For example, the second current collector 176 may have a structure in which the support portion 176a for indirectly connecting the second uncoating portion coupling portion 176b and the case coupling portion 176c is not included and / or a structure in which the uncoating portion 146b and the case coupling portion 176c are directly connected to each other.

[0666] The support portion 176a and the second uncoated portion coupling portion 176b are disposed below the electrode assembly 110. The second uncoated portion coupling portion 176b is coupled to the bending surface area F of the uncoated portion 146b. In addition to the second uncoated portion coupling portion 176b, the support portion 176a may also be coupled to the uncoated portion 146b. The second uncoated portion coupling portion 176b and the bending surface area F of the uncoated portion 146b may be coupled by welding. Welding may be replaced by ultrasonic welding or spot welding. When a curling portion 180 is formed on the battery case 171, the support portion 176a and the second uncoated portion coupling portion 176b are positioned higher than the curling portion 180.

[0667] The support portion 176a has a current collector hole 176d formed at a position corresponding to the hole formed at the core C of the electrode assembly 110. The core C of the electrode assembly 110 and the current collector hole 176d communicated with each other may be used as a welding rod inserted for welding between the terminal 172 and the terminal coupling portion 144c of the first current collector 144 or a passage for irradiating a laser beam.

[0668] The core radius (r c ) compared to the collector hole 176d, the collector hole 176d may have a 0.5r c If the radius of the collector hole 176d is 0.5r c To 1.0r c , when exhaust occurs in the cylindrical battery 200, the following phenomenon is prevented: the winding structure of the separator or electrode near the core C of the electrode assembly 110 is pushed out of the core C due to the exhaust pressure. When the radius of the current collector hole 176d is greater than 1.0r c , the opening of the core C is maximized, so the electrolyte can be easily injected during the electrolyte injection process.

[0669] When the second non-coating portion coupling portion 176b is provided in plurality, the plurality of second non-coating portion coupling portions 176b may have a shape extending substantially radially from the support portion 176a of the second current collector 176 toward the sidewall of the battery case 171. The plurality of second non-coating portion coupling portions 176b may be positioned to be spaced apart from each other along the periphery of the support portion 176a.

[0670] The housing connection part 176c may be provided in plurality. In this case, the plurality of housing connection parts 176c may have a shape extending substantially radially from the center of the second current collector 176 toward the side wall of the battery housing 171. Therefore, the electrical connection between the second current collector 176 and the battery housing 171 may be performed at a plurality of points. Since the connection for electrical connection is performed at a plurality of points, the connection area may be maximized, thereby minimizing the resistance. The plurality of housing connection parts 176c may be positioned to be spaced apart from each other along the periphery of the support part 176a. At least one housing connection part 176c may be located between the second uncoated part connection parts 176b adjacent to each other. The plurality of housing connection parts 176c may be coupled to, for example, the crimping part 180 in the inner surface of the battery housing 171. The housing connection part 176c may be coupled to the lower surface of the crimping part 180, in particular by laser welding. Welding may be replaced by, for example, ultrasonic welding, spot welding, etc. By welding and coupling a plurality of housing coupling portions 176c to the curling portion 180 in this manner, the current path can be radially distributed so that the resistance level of the cylindrical battery 200 is limited to about 4 milliohms or less. In addition, since the lower surface of the curling portion 180 has a shape extending in a direction substantially parallel to the upper surface of the battery housing 171 (i.e., in a direction substantially perpendicular to the side wall of the battery housing 171), and the housing coupling portion 176c also has a shape extending in the same direction (i.e., radial direction and circumferential direction), the housing coupling portion 176c can stably contact the curling portion 180. In addition, since the housing coupling portion 176c stably contacts the flat portion of the curling portion 180, the two components can be smoothly welded, thereby improving the coupling force between the two components and minimizing the increase in resistance at the coupling portion.

[0671] The case coupling portion 176 c may include a contact portion 176 e coupled to the inner surface of the battery case 171 and a connection portion 176 f for connecting the support portion 176 a and the contact portion 176 e .

[0672] The contact portion 176e is coupled to the inner surface of the battery case 171. In the case where the crimping portion 180 is formed on the battery case 171, the contact portion 176e may be coupled to the crimping portion 180 as described above. More specifically, the contact portion 176e may be electrically coupled to a flat portion formed at the lower surface of the crimping portion 180 formed on the battery case 171, and may be interposed between the lower surface of the crimping portion 180 and the first gasket 178b. In this case, in order to stabilize the contact and coupling, the contact portion 176e may have a shape extending a predetermined length on the crimping portion 180 in the circumferential direction of the battery case 171.

[0673] The connecting portion 176f can be bent at an obtuse angle. The bending point can be higher than the midpoint of the connecting portion 176f. When the connecting portion 176f is bent, the contact portion 176e can be stably supported on the flat surface of the curling portion 180. The connecting portion 176f is divided into a lower portion and an upper portion based on the bending point, and the lower portion can have a greater length than the upper portion. In addition, the lower portion of the bending point can have a larger inclination angle based on the surface of the support portion 176a than the upper portion. When the connecting portion 176f is bent, the pressure (force) applied in the vertical direction of the battery housing 171 can be buffered. For example, in the process of determining the size of the battery housing 171, when the pressure is transmitted to the contact portion 176e so that the contact portion 176e moves vertically toward the support portion 176b, the bending point of the connecting portion 176f moves upward, so that the shape of the connecting portion 176 is deformed to buffer the stress.

[0674] In addition, the maximum distance from the center of the second current collector 176 to the end of the second non-coating portion coupling portion 176b in the radial direction of the electrode assembly 110 is preferably equal to or less than the inner diameter of the battery case 171 in the region where the curling portion 180 is formed, that is, the minimum inner diameter of the battery case 171. This is to prevent the end of the second non-coating portion coupling portion 176b from pressing the edge of the electrode assembly 110 during the sizing process of compressing the battery case 171 in the height direction.

[0675] The second uncoated portion coupling portion 176b includes a hole 176g. The hole 176g may be used as a passage through which the electrolyte may move. The welding pattern 176h formed by welding between the second uncoated portion coupling portion 176b and the bent surface region F may have a structure extending in the radial direction of the electrode assembly 110. The welding pattern 176h may be a line pattern or a dot array pattern.

[0676] The welding pattern 176h corresponds to the welding area. Therefore, it is preferred that the welding pattern 176h overlaps the stacking number consistent area b1 of the bending surface area F located in the lower part of the electrode assembly 110 by more than 50%. The welding pattern 176h that does not overlap with the stacking number consistent area b1 may overlap with the stacking number reduced area b2. More preferably, the entire welding pattern 176h may overlap with the stacking number consistent area b1 of the bending surface area F. In the bending surface area F at the upper part of the point where the welding pattern 176h is formed, the stacking number consistent area b1 and the optional stacking number reduced area b2 preferably have a stacking number of 10 or more.

[0677] The outer diameters of the first current collector 144 and the second current collector 176 described above are different from each other. The outer diameter is the outer diameter of the outer edge of the contact area between the bending surface area F and the current collector. The outer diameter is defined as the maximum value of the distance between the two points where a straight line passing through the center of the core C of the electrode assembly intersects with the edge of the contact area. Since the second current collector 176 is located inside the curling portion 180, its outer diameter is smaller than the outer diameter of the first current collector 144. In addition, the length of the welding pattern 144f of the first current collector 144 is longer than the length of the welding pattern 176h of the second current collector 176. Preferably, the welding pattern 144f and the welding pattern 176h may extend toward the periphery from substantially the same point based on the center of the core C.

[0678] The cylindrical batteries 170 , 180 , 200 , 220 according to the embodiments of the present disclosure have an advantage in that electrical connection can be performed at the upper portion thereof.

[0679] Fig.28 is a top plan view illustrating a state in which a plurality of cylindrical batteries 200 are electrically connected, and Fig.29 yes Fig.28 The cylindrical battery 200 may be replaced by cylindrical batteries 170, 180, 220 having different structures.

[0680] Reference Fig.28 and Fig.29 , a plurality of cylindrical batteries 200 may be connected in series and in parallel at the upper portion of the cylindrical batteries 200 using the bus bar 210. The number of cylindrical batteries 200 may be increased or decreased in consideration of the capacity of the battery pack.

[0681] In each cylindrical battery 200 , the terminal 172 may have a positive polarity, and the flat surface 171 a around the terminal 172 of the battery case 171 may have a negative polarity, or vice versa.

[0682] Preferably, a plurality of cylindrical batteries 200 may be arranged in multiple columns and rows. Columns are arranged in the vertical direction on the drawing, and rows are arranged in the left-right direction on the drawing. In addition, in order to maximize space efficiency, the cylindrical batteries 200 may be arranged in the tightest packaging structure. When an equilateral triangle is formed by connecting the centers of the terminals 172 exposed outside the battery housing 171 to each other, the tightest packaging structure is formed. Preferably, the bus bar 210 connects the cylindrical batteries 200 arranged in the same column in parallel to each other, and connects the cylindrical batteries 200 arranged in two adjacent columns in series to each other.

[0683] Preferably, the bus bar 210 may include a body portion 211 , a plurality of first bus bar terminals 212 for series connection and parallel connection, and a plurality of second bus bar terminals 213 .

[0684] The body portion 211 may extend between adjacent terminals 172 along the column of the cylindrical batteries 200. Alternatively, the body portion 211 may extend along the column of the cylindrical batteries 200, and the body portion 211 may be regularly bent like a zigzag.

[0685] A plurality of first bus bar terminals 212 may extend in one side direction of the body portion 211 and may be electrically connected to the terminals 172 of the cylindrical batteries 200 located in one side direction. The electrical connection between the first bus bar terminals 212 and the terminals 172 may be achieved by laser welding, ultrasonic welding, etc.

[0686] A plurality of second bus bar terminals 213 may extend in another lateral direction of the body portion 211 and may be electrically coupled to the flat surface 171a around the terminal 172 located in another lateral direction. The electrical coupling between the second bus bar terminals 213 and the flat surface 171a may be performed by laser welding, ultrasonic welding, etc.

[0687] Preferably, the main body 211, the plurality of first bus bar terminals 212, and the plurality of second bus bar terminals 213 may be made of a conductive metal plate. The metal plate may be, for example, an aluminum plate or a copper plate, but the present disclosure is not limited thereto. In a modified example, the main body 211, the plurality of first bus bar terminals 212, and the second bus bar terminals 213 may be manufactured as separate parts and then connected to each other by welding or the like.

[0688] The cylindrical battery 200 of the present disclosure as described above has the following structure: the resistance is minimized by expanding the welding area by means of the bent surface area F, reusing the current path by means of the second current collector 176, minimizing the current path length, etc. The AC resistance of the cylindrical battery 200 measured between the positive electrode and the negative electrode (i.e., between the terminal 172 and the flat surface 171a around the terminal 172) by a resistance meter may be about 0.5 milliohms to 4 milliohms, preferably 1 milliohms to 4 milliohms, which is suitable for fast charging.

[0689] In the cylindrical battery 200 according to the present disclosure, since the terminal 172 having a positive polarity and the flat surface 171 a having a negative polarity are located in the same direction, the cylindrical battery 200 is easily electrically connected using the bus bar 210 .

[0690] In addition, since the terminal 172 of the cylindrical battery 200 and the flat surface 171 a around the terminal 172 have a large area, the coupling area of ​​the bus bar 210 can be sufficiently ensured to sufficiently reduce the resistance of the battery pack including the cylindrical battery 200 .

[0691] In addition, since electrical wiring can be performed on the upper portion of the cylindrical battery 200, there is an advantage in that the energy density per unit volume of the battery module / pack is maximized.

[0692] The cylindrical battery according to the above-described embodiment (modification) may be used to manufacture a battery pack.

[0693] Fig.30 is a diagram schematically showing a battery pack according to an embodiment of the present disclosure.

[0694] Reference Fig.30 , the battery pack 300 according to the embodiment of the present disclosure includes an aggregate to which cylindrical batteries 301 are electrically connected and a battery pack case 302 for accommodating the aggregate. The cylindrical batteries 301 may be any of the batteries according to the above embodiments (variations). In the drawings, for the sake of convenience of illustration, components such as bus bars for electrical connection of the cylindrical batteries 301, cooling units, and external terminals are not drawn.

[0695] The battery pack 300 may be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheel vehicle or a two-wheel vehicle.

[0696] Fig.31 It schematically shows the Fig.30 FIG. 3 is a diagram of a battery pack 300 for a vehicle.

[0697] Reference Fig.31 , the vehicle V according to the embodiment of the present disclosure includes the battery pack 300 according to the embodiment of the present disclosure. The vehicle V operates by receiving power from the battery pack 300 according to the embodiment of the present disclosure.

[0698] According to one aspect of the present disclosure, by using the uncoated portions themselves protruding at the upper and lower portions of the electrode assembly as electrode tabs, the internal resistance of the battery may be reduced and the energy density may be increased.

[0699] According to another aspect of the present disclosure, by improving the structure of the uncoated portion of the electrode assembly so that the electrode assembly and the inner circumference of the battery case do not interfere during the process of forming the curling portion of the battery, a short circuit inside the cylindrical battery due to local deformation of the electrode assembly can be prevented.

[0700] According to another aspect of the present disclosure, by improving the structure of the uncoated portion of the electrode assembly, the uncoated portion can be prevented from being torn when being bent, and by sufficiently increasing the number of overlapping layers of the uncoated portion, the welding strength of the current collector can be improved.

[0701] According to another aspect of the present disclosure, the characteristics of the area of ​​the welding current collector can be improved by applying a segment structure to the uncoated portion of the electrode and optimizing the size (width, height, spacing) of the segment to sufficiently increase the number of segment stacking areas serving as the welding target area.

[0702] According to another aspect of the present disclosure, an electrode assembly having the following structure can be provided: it prevents the active material layer from being damaged by releasing stress by rupturing the welding portion and / or the uncoated portion (segment) adjacent thereto when stress higher than a threshold value is concentrated in the area of ​​the welding current collector in the electrode assembly.

[0703] According to still another aspect of the present disclosure, by applying a structure in which a current collector is welded to a wide area of ​​a bent surface area formed by bending a segment, an electrode assembly having improved energy density and reduced resistance may be provided.

[0704] According to still another aspect of the present disclosure, a cylindrical battery having an improved design enabling electrical wiring to be performed on an upper portion thereof may be provided.

[0705] According to another aspect of the present disclosure, by improving the structure of the uncoated portion of the core adjacent to the electrode assembly, the cavity in the core of the electrode assembly is prevented from being blocked when the uncoated portion is bent, so that the electrolyte injection process and the process of welding the battery case (or terminal) and the current collector can be easily performed.

[0706] According to still another aspect of the present disclosure, a cylindrical battery having a structure in which internal resistance is low, an internal short circuit is prevented, and welding strength between a current collector and an uncoated portion is improved, and a battery pack and a vehicle including the cylindrical battery may be provided.

[0707] Specifically, the present disclosure may provide a cylindrical battery having a diameter-to-height ratio of 0.4 or more and a resistance of 4 milliohms or less, and a battery pack and a vehicle including the cylindrical battery.

[0708] The present disclosure has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present disclosure, are given by way of example only, because various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art based on this detailed description.

Claims

1. An electrode assembly, comprising: a first electrode; a second electrode; as well as a separator interposed between the first electrode and the second electrode, the first electrode, the second electrode, and the separator being wound around a winding axis to define a core and a periphery of the electrode assembly, The first electrode includes a first active material portion and a first uncoated portion, the first active material portion is coated with an active material layer along a winding direction, and the first uncoated portion is not coated with an active material layer and is exposed outside the separator, wherein the first uncoated portion comprises a plurality of sections that can be bent independently, wherein the plurality of segments are defined as electrode joints in a bent state along a radial direction of the electrode assembly, and wherein at least a portion of the first uncoated portion having the plurality of sections includes a cutout portion extending in a direction parallel to the winding direction.

2. The electrode assembly according to claim 1, in, Each of the plurality of segments has a geometric shape connecting one or more straight lines, one or more curved lines, or a combination thereof.

3. The electrode assembly according to claim 1, in, A cutting groove is interposed between segments adjacent in the winding direction, and the cutout portion is provided in a region of the first uncoated portion between a bottom of the cutting groove and the first active material portion.

4. The electrode assembly according to claim 3, in, The cutout portion is continuously formed in one direction parallel to the winding direction of the electrode assembly in a region of the first non-coating portion where the plurality of sections are provided.

5. The electrode assembly according to claim 3, in, The cutout portion is discontinuously formed in a direction parallel to the winding direction of the electrode assembly in a region of the first non-coating portion where the plurality of sections are provided.

6. The electrode assembly according to claim 5, in, The cut portion includes a plurality of sub-cut portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the first uncoated portion has a region where the length of the sub-cut portions gradually increases or decreases in the winding direction of the electrode assembly.

7. The electrode assembly according to claim 5, in, The cut portion includes a plurality of sub-cut portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the first uncoated portion has a region where an interval distance between adjacent sub-cut portions gradually increases or decreases in the winding direction of the electrode assembly.

8. The electrode assembly according to claim 5, in, The cutout portion includes a plurality of sub-cutout portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the plurality of sub-cutout portions have substantially the same height in a winding axis direction.

9. The electrode assembly according to claim 5, in, The cut portion includes a plurality of sub-cut portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the first uncoated portion has regions where heights of the sub-cut portions in a winding axis direction are different from each other.

10. The electrode assembly according to claim 5, in, The cut portion includes a plurality of sub-cut portions discontinuously formed in a direction parallel to the winding direction of the electrode assembly, and the first uncoated portion has a region where the distance between the cutting groove and the sub-cut portions gradually increases or decreases along the winding direction of the electrode assembly.

11. The electrode assembly according to claim 3, in, A distance between the cutout portion and the bottom of the cutting groove is 0.1 mm to 1.9 mm.

12. The electrode assembly according to claim 1, in, The cutout portion includes an array of a plurality of perforations formed along the winding direction of the electrode assembly.

13. The electrode assembly according to claim 12, in, The perforations have a circular, square, diamond, triangular or oval shape.

14. The electrode assembly according to claim 12, in, The cutout portion includes an array of a plurality of grooves formed along the winding direction of the electrode assembly.

15. The electrode assembly according to claim 14, in, The groove has a circular, square, diamond, triangular or oval shape.

16. The electrode assembly according to claim 3, in, An insulating coating layer is provided on a boundary between an area of ​​the uncoated portion that exists in an area where the bottom of the cutting groove and the first active material portion are spaced apart from each other and the first active material portion, and a distance from the bottom of the cutting groove to the cut portion is smaller than a distance from the cut portion to the insulating coating layer.

17. The electrode assembly according to claim 1, further comprising: a current collector welded to a bent surface area formed by bending the plurality of segments in the radial direction of the electrode assembly, Wherein, at least a portion of the cutout portion is arranged to overlap with a lower region of the segment welded to the current collector.

18. The electrode assembly according to claim 17, in, The cutout portion does not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the current collector.

19. The electrode assembly according to claim 1, in, The second electrode includes a second active material portion coated with an active material layer along the winding direction and a second uncoated portion not coated with the active material layer, the second uncoated portion includes a plurality of segments that can be bent independently, the plurality of segments are defined as electrode joints in a bent state along the radial direction of the electrode assembly, and at least a portion of the second uncoated portion having the plurality of segments includes a cutout portion extending in a direction parallel to the winding direction.

20. The electrode assembly according to claim 19, further comprising: a second current collector welded to a bent surface area formed by bending the plurality of sections of the second uncoated portion, wherein the cutout portion formed in the second non-coating portion is formed between the second active material portion and the segment welded to the second current collector.

21. The electrode assembly according to claim 20, in, The cutout portion formed in the second non-coating portion does not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the second current collector.

22. A battery, comprising: An electrode assembly, the electrode assembly comprising a first electrode, a second electrode and a separator interposed between the first electrode and the second electrode, the first electrode, the second electrode and the separator being wound around a winding axis to define a core and a periphery of the electrode assembly, wherein the first electrode comprises a first active material portion and a first uncoated portion, the first active material portion being coated with an active material layer along a winding direction, the first uncoated portion being uncoated with an active material layer and exposed outside the separator, the first uncoated portion comprising a plurality of segments that can be bent independently, the plurality of segments being defined as electrode tabs in a bent state along a radial direction of the electrode assembly, and at least a portion of the first uncoated portion having the plurality of segments comprising a cutout portion extending in a direction parallel to the winding direction; a battery case having an open end and a bottom opposite to the open end, the battery case being configured to accommodate the electrode assembly in a space between the open end and the bottom, and the battery case being electrically connected to one of the first electrode and the second electrode to have a first polarity; a sealing body configured to seal the open end of the battery case; and A terminal has a surface exposed to the outside and is electrically connected to the other of the first electrode and the second electrode to have a second polarity.

23. The battery according to claim 22, in, The sealing body includes a cover configured to seal the open end of the battery case, a gasket inserted between the edge of the cover and the open end of the battery case, and a pressing edge portion configured to extend and bend toward the interior of the battery case and configured to surround and fix the edge of the cover together with the gasket, and the terminal having the second polarity is the cover.

24. The battery according to claim 22, further comprising: a first current collector welded to a bent surface region formed by bending the plurality of sections of the first non-coating portion in the radial direction of the electrode assembly, wherein the cutout portion formed in the first non-coating portion is formed between a section welded to the first current collector and the first active material portion.

25. The battery according to claim 24, in, The cutout portion does not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the current collector.

26. The battery according to claim 24, in, The terminal is a rivet terminal which is insulatedly mounted in a penetration hole formed in the bottom of the battery case and is electrically connected to the first current collector to have a second polarity.

27. The battery according to claim 24, further comprising: An insulator is interposed between an inner surface of the bottom of the battery case and an upper surface of the first current collector to electrically insulate the inner surface of the bottom of the battery case from the first current collector.

28. The battery according to claim 22, in, The second electrode includes a second active material portion coated with an active material layer along the winding direction and a second uncoated portion not coated with the active material layer, the second electrode has the first polarity, the second uncoated portion includes a plurality of segments that can be bent independently, the plurality of segments are defined as electrode joints in a bent state along the radial direction of the electrode assembly, and at least a portion of the second uncoated portion having the plurality of segments includes a cutout portion extending in a direction parallel to the winding direction.

29. The battery according to claim 28, further comprising: a second current collector welded to a bent surface area formed by bending the plurality of sections of the second uncoated portion, wherein the cutout portion formed in the second non-coating portion is formed between a section welded to the second current collector and the second active material portion.

30. The battery according to claim 29, in, The cutout portion formed in the second non-coating portion does not intersect an imaginary line passing through a center of an upper side and a center of a lower side of the segment welded to the second current collector.

31. The battery according to claim 29, in, The battery case includes a curling portion pressed inwardly on an inner wall adjacent to the open end, and at least a portion of an edge of the second current collector is electrically connected to the curling portion.

32. The battery according to claim 31, in, The sealing body includes: a cover having an edge supported by the curling portion and having no polarity; a gasket inserted between the edge of the cover and the open end of the battery case; and a pressing portion, which is configured to extend and bend toward the inner side of the open end of the battery case and is configured to surround and fix the edge of the cover together with the gasket, and at least a portion of the edge of the second current collector is inserted and fixed between the curling portion and the gasket through the pressing portion.

33. The battery according to claim 31, in, At least a portion of the edge of the second current collector is welded to the curled portion.

34. A battery pack comprising a plurality of batteries, wherein the batteries are batteries according to any one of claims 22 to 33.

35. The battery pack according to claim 34, in, The ratio of the diameter to the height of the battery is greater than 0.

4.

36. The battery pack according to claim 35, in, The battery has a 46110, 4875, 48110, 4880 or 4680 form factor.

37. The battery pack according to claim 34, in, The battery has a resistance of less than 4 milliohms.

38. The battery pack according to claim 34, in, The plurality of batteries are arranged in a predetermined number of rows, and the terminal of each battery is arranged to face upward with an outer surface of the bottom of the battery case.

39. The battery pack according to claim 38, in, The battery pack includes a plurality of bus bars that connect the plurality of batteries in series and in parallel, the plurality of bus bars are arranged on the upper portion of the plurality of batteries, and each bus bar includes a main body portion extending between terminals of adjacent batteries, a plurality of first bus bar terminals extending in a one side direction of the main body portion and electrically connected to the terminals of the batteries located in the one side direction, and a plurality of second bus bar terminals extending in the other side direction of the main body portion and electrically connected to the outer surface of the bottom of the battery casing of the battery located in the other side direction.

40. A vehicle comprising a battery pack according to any one of claims 34 to 39.

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