battery

Abstract

The present application provides a battery with high reliability in which multiple tabs and a current collecting portion are stably connected. In a preferred embodiment of the battery disclosed herein, in an electrode body (20a (20b, 20c)), a center (C1) of a root width of a first tab (22t1) and a center (C3) of a root width of a third tab (22t3) are arranged in an offset state in a vertical direction (Z), and a center (C2) of a root width of a second tab (22t2) and a center (C4) of a root width of a fourth tab (22t4) are arranged in an offset state in the vertical direction (Z).

Description

Technical Field

[0001] This invention relates to a battery. Background Technology

[0002] For example, Patent Document 1 discloses a battery in which a positive electrode tab assembly is provided at one end along the length of the wound electrode body and a negative electrode tab assembly is provided at the other end. Furthermore, it discloses a technique for connecting the tab assembly to the electrode current collector in a bent state.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2021 / 060010 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Furthermore, such a wound electrode body is manufactured, for example, by simultaneously winding a current collector having a long strip and the positive and negative electrodes (hereinafter, sometimes collectively referred to as "electrodes") of tabs formed at multiple locations along the long strip direction of the current collector, separated by spacers, into a winding core and then forming it into a flat shape. During the manufacture of this wound electrode body, the tabs near the innermost circumference of the wound electrode body may be bent. If the tabs near the innermost circumference of the wound electrode body are bent, it may be impossible to stably connect the stacked tabs to the current collector.

[0008] The purpose of this invention is to provide a battery with a wound electrode body that has appropriately improved performance.

[0009] Solution for solving the problem

[0010] To achieve this objective, the present invention provides a battery comprising: a flat wound electrode body formed by winding a first electrode and a second electrode of a different polarity from the first electrode with a spacer between them; and a battery casing for housing the wound electrode body. A plurality of tabs connected to the first electrode protrude from one end of the wound electrode body in the direction of the winding axis, the plurality of tabs being connected to a current-collecting portion of the first electrode. The wound electrode body has a first region located on one side of the winding axis and a second region located on the other side of the winding axis in the thickness direction of the wound electrode body. The aforementioned plurality of tabs includes a first tab, a second tab, a third tab, and a fourth tab. The first tab, located in the first region, is situated at the position closest to the winding axis (innermost circumference) in the thickness direction. The second tab, located in the second region, is also located at the same position (innermost circumference) in the thickness direction. The third tab, located in the first region, is situated at the position furthest from the winding axis (outermost circumference) in the thickness direction. The fourth tab, located in the second region, is situated at the same position (outermost circumference) in the thickness direction. At one end of each tab, the center C1 of the root width of the first tab and the center C3 of the root width of the third tab are offset in the vertical direction relative to the thickness direction. Similarly, the center C2 of the root width of the second tab and the center C4 of the root width of the fourth tab are offset in the vertical direction. With this battery structure, it is possible to appropriately confirm whether the tab near the innermost circumference, where tab bending is prone to occur, has bent. Furthermore, by selecting and using electrode bodies whose tabs are not bent, a highly reliable battery can be obtained where multiple tabs are stably connected to the current collector. Moreover, an unstable connection between multiple tabs and the current collector is not preferable from the viewpoint of battery performance.

[0011] In one embodiment of the battery disclosed herein, when the distance between the center C1 and the center C2 in the vertical direction relative to the thickness direction is set as G1, and the distance between the center C3 and the center C4 in the vertical direction is set as G2, G1 and G2 satisfy the relationship G1 > G2.

[0012] In one embodiment of the battery disclosed herein, the end of the first electrode where the winding begins is located in the first region, and in the vertical direction, the center C1 is located at a position further away from the winding axis of the winding electrode body than the center C2.

[0013] In one embodiment of the battery disclosed herein, an outer casing and a sealing plate that seals the opening are provided. The outer casing has a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall. The wound electrode body is arranged such that the winding axis is along the bottom wall. The center C3 and the center C4 are located at a position closer to the sealing plate than the winding axis.

[0014] In one embodiment of the battery disclosed herein, the wound electrode body further comprises a fifth tab and a sixth tab on the first electrode. The fifth tab is disposed between the first tab and the third tab in the thickness direction, and the sixth tab is disposed between the second tab and the fourth tab in the thickness direction. At one end of the wound electrode body in the winding axis direction, when the center of the root width of the fifth tab is set as center C5, the center of the root width of the sixth tab is set as center C6, and the distance between the center C5 and the center C6 in the vertical direction is set as G3, G1, G2, and G3 satisfy the relationship G2 < G3 < G1.

[0015] In one embodiment of the battery disclosed herein, when a straight line passing through the center C1 and the center C3 is designated as a first straight line, and a straight line passing through the center C2 and the center C4 is designated as a second straight line, the first straight line and the second straight line are inclined relative to the thickness direction.

[0016] In one embodiment of the battery disclosed herein, the first straight line and the second straight line do not lie on the same straight line in the aforementioned vertical direction.

[0017] In one embodiment of the battery disclosed herein, the first straight line and the second straight line are inclined in the same direction in the thickness direction.

[0018] In a preferred embodiment of the battery disclosed herein, the plurality of tabs are connected to the first electrode current collector in a collected state. The first tab is closer to the first electrode current collector than the third tab. The length of the third tab in its protruding direction is greater than the length of the first tab in its protruding direction, and the length of the fourth tab in its protruding direction is smaller than the length of the second tab in its protruding direction. According to this structure, when the plurality of tabs are collected, the positions of the front ends of the plurality of tabs can be properly aligned, which is therefore preferable.

[0019] In one embodiment of the battery disclosed herein, the plurality of tabs are connected to the first electrode current collector in a foil-like manner, the first tab being closer to the first electrode current collector than the third tab, and at one end of the first tab, the root width of the third tab is greater than the root width of the first tab, and the root width of the fourth tab is smaller than the root width of the second tab.

[0020] In a preferred embodiment of the battery disclosed herein, the plurality of tabs are connected to the first electrode current collector in a bent state. This structure allows for the production of a battery with high volumetric energy density, and is therefore preferred.

[0021] In one embodiment of the battery disclosed herein, a pair of end faces of the wound electrode body have flat portions and a pair of curved portions disposed at both ends of the flat portions, and the end of the first electrode at the end of winding is disposed in the curved portions.

[0022] In one embodiment of the battery disclosed herein, a plurality of second electrode tabs connected to the aforementioned second electrode protrude from the opposite end in the direction of the winding axis of the aforementioned wound electrode body.

[0023] In one embodiment of the battery disclosed herein, two wound electrode bodies are disposed within the battery casing, wherein the values ​​of G1 of the two wound electrode bodies are different, and / or the values ​​of G2 of the two wound electrode bodies are different.

[0024] In one embodiment of the battery disclosed herein, the G1 of one of the two wound electrode bodies is larger than the G1 of the other wound electrode body.

[0025] In one embodiment of the battery disclosed herein, the difference between the G1 of one of the wound electrode bodies and the G1 of the other wound electrode body is greater than the difference between the G2 of one of the wound electrode bodies and the G2 of the other wound electrode body.

[0026] In one embodiment of the battery disclosed herein, another wound electrode body, namely a third electrode body, is further disposed within the battery casing. The G1 of the third electrode body is different from the G1 of one of the wound electrode bodies and the G1 of the other wound electrode body, and / or the G2 of the third electrode body is different from the G2 of one of the wound electrode bodies and the G2 of the other wound electrode body. Attached Figure Description

[0027] Figure 1 This is a perspective view schematically illustrating one embodiment of a battery.

[0028] Figure 2 It is along Figure 1A schematic longitudinal section view of line II-II.

[0029] Figure 3 It is along Figure 1 A schematic longitudinal section view of line III-III.

[0030] Figure 4 It is along Figure 1 A schematic cross-sectional view of line IV-IV.

[0031] Figure 5 It is a schematic three-dimensional view of the electrode assembly installed on the sealing plate.

[0032] Figure 6 It is a schematic three-dimensional view of an electrode body with a positive second collector and a negative second collector installed.

[0033] Figure 7 This is a schematic diagram showing the structure of a wound electrode body according to one embodiment.

[0034] Figure 8A This is a schematic diagram showing one end face of the positive electrode side of a wound electrode body according to one embodiment.

[0035] Figure 8B This is a schematic diagram showing one end face of the positive electrode side of a wound electrode body according to one embodiment.

[0036] Figure 9 It is a schematic perspective view of a sealing plate with a positive terminal, a negative terminal, a first positive current collector, a first negative current collector, a positive insulating component, and a negative insulating component installed.

[0037] Figure 10 It is Figure 9 A 3D view of the sealing plate turned upside down.

[0038] Figure 11A This is a schematic diagram illustrating the positive electrode (positive electrode plate) of one embodiment.

[0039] Figure 11B This is a schematic diagram illustrating the negative electrode (negative electrode sheet) of one embodiment.

[0040] Figure 12 This is a schematic diagram illustrating the fabrication of a wound body in a battery manufacturing method according to one embodiment.

[0041] Figure 13A This is a schematic diagram illustrating the forming of a wound body in a battery manufacturing method according to one embodiment.

[0042] Figure 13BThis is a schematic explanatory diagram illustrating the forming of a wound body in a battery manufacturing method according to one embodiment.

[0043] Figure 14 This is a schematic diagram showing one end face of the positive electrode side of the wound electrode body in the second embodiment.

[0044] Figure 15 This is a schematic diagram showing one end face of the positive electrode side of the wound electrode body in the third embodiment.

[0045] Figure 16 This is a schematic diagram showing one end face of the positive electrode side of the wound electrode body according to the fourth embodiment.

[0046] Figure 17 This is a schematic diagram showing one end face of the positive electrode side of the wound electrode body according to the fifth embodiment.

[0047] Figure 18 This is a schematic diagram showing one end face of the positive electrode side of the wound electrode body according to the sixth embodiment.

[0048] Figure 19 This is a schematic diagram showing one end face of the positive electrode side of the wound electrode body according to the seventh embodiment.

[0049] Explanation of reference numerals in the attached figures

[0050] 10 Battery casing

[0051] 12 outer body

[0052] 14 Sealing board

[0053] 15 injection holes

[0054] 16 Sealing components

[0055] 17 Gas discharge valve

[0056] 18 and 19 terminal insertion holes

[0057] 20 electrode assembly

[0058] 20a~20c electrode body

[0059] 22 Positive electrode

[0060] 24 Negative electrode

[0061] 26 spacers

[0062] 27. The end where the positive electrode winding begins.

[0063] 28. The end of the positive electrode winding.

[0064] 30 Positive extremes

[0065] 32 Positive electrode external conductive component

[0066] 40 Negative extremes

[0067] 42 External conductive component of negative electrode

[0068] 50 Positive current collector

[0069] 60 Negative current collector

[0070] 70 Positive electrode internal insulation components

[0071] 80 Negative electrode internal insulation components

[0072] 90 gasket

[0073] 92 External insulation components

[0074] 100 batteries

[0075] 200 winding body

[0076] 201 core

[0077] 202 Conveyor Roller

[0078] 204 stamping press. Detailed Implementation

[0079] Hereinafter, with reference to the accompanying drawings, several preferred embodiments of the technology disclosed herein will be described. Furthermore, matters other than those specifically mentioned in this specification and necessary for the implementation of the invention (e.g., the general structure and manufacturing process of a battery that does not characterize the invention) can be understood by those skilled in the art based on prior art. The invention can be implemented based on the disclosures in this specification and common technical knowledge in the field. Additionally, the following description is not intended to limit the technology disclosed herein to the following embodiments. Furthermore, in this specification, the expression "A~B" indicating a numerical range means greater than A and less than B, and includes meaning greater than A and less than B.

[0080] Furthermore, in this specification, "battery" refers to a general energy storage device capable of extracting electrical energy, encompassing both primary and secondary batteries. Additionally, in this specification, "secondary battery" refers to a general energy storage device capable of repeated charging and discharging, encompassing so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries, as well as capacitors (physical batteries) such as double-layer capacitors.

[0081] <An overview of the battery's structure>

[0082] Figure 1 This is a 3D image of battery 100. Figure 2 It is along Figure 1 A schematic longitudinal section view of line II-II. Figure 3 It is along Figure 1 A schematic longitudinal section view of line III-III. Figure 4 It is along Figure 1 A schematic cross-sectional view along line IV-IV. In the following description, the reference numerals L, R, F, Rr, U, and D in the figure represent left, right, front, back, top, and bottom, respectively, and the reference numerals X, Y, and Z in the figure represent the direction of the short side of battery 100, the direction of the long side orthogonal to the short side, and the up and down direction, respectively. However, these directions are only for ease of explanation and do not limit the arrangement of battery 100.

[0083] like Figure 2 As shown, the battery 100 includes a battery casing 10 and an electrode assembly 20. In addition to the battery casing 10 and the electrode assembly 20, the battery 100 of this embodiment includes a positive terminal 30, a positive external conductive member 32, a negative terminal 40, a negative external conductive member 42, an external insulating member 92, a positive current collector 50, a negative current collector 60, a positive internal insulating member 70, and a negative internal insulating member 80. Although not shown in the figures, the battery 100 of this embodiment also includes an electrolyte. The battery 100 is a lithium-ion secondary battery. The internal resistance of the battery 100 can be, for example, about 0.2 to 2.0 mΩ.

[0084] The battery casing 10 is a frame that houses the electrode assembly 20. The battery casing 10 has a flat, bottomed cuboid shape (square). The material of the battery casing 10 can be the same as conventionally used materials, without particular limitation. The battery casing 10 is preferably made of a metal with a specified strength. Specifically, the tensile strength of the metal used in the battery casing 10 is appropriately 50 N / mm². 2 ~200N / mm 2 The physical property value (rigidity modulus) of the metal used in the battery casing 10 is preferably around 20 GPa to 100 GPa. Examples of such metal materials include aluminum, aluminum alloys, iron, and iron alloys.

[0085] Furthermore, the battery casing 10 includes an outer body 12, a sealing plate 14, and a gas vent valve 17. The outer body 12 is a flat, square (hexahedral) container with one side forming an opening 12h. Specifically, as... Figure 1As shown, the outer casing 12 has a generally rectangular bottom wall 12a, a pair of first side walls 12b extending upward in a U-shape from the short side of the bottom wall 12a and facing each other, and a pair of second side walls 12c extending upward in a U-shape from the long side of the bottom wall 12a and facing each other. The area of ​​the second side walls 12c is smaller than the area of ​​the first side walls 12b. Moreover, an opening 12h is formed on the upper surface of the outer casing 12, which is surrounded by the pair of first side walls 12b and the pair of second side walls 12c. A sealing plate 14 is installed on the outer casing 12 to block the opening 12h of the outer casing 12. The sealing plate 14 is a plate that is generally rectangular in shape when viewed from above. The sealing plate 14 faces the bottom wall 12a of the outer casing 12. The battery casing 10 is formed by joining (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the outer casing 12. The sealing plate 14 can be joined by welding, such as laser welding.

[0086] like Figure 1 and Figure 2 As shown, a gas discharge valve 17 is formed on the sealing plate 14. The gas discharge valve 17 is configured to open and discharge gas from the battery housing 10 when the pressure inside the battery housing 10 reaches or exceeds a predetermined value.

[0087] In addition, the sealing plate 14, besides the aforementioned gas vent valve 17, is provided with an injection hole 15 and two terminal insertion holes 18 and 19. The injection hole 15 communicates with the internal space of the outer casing 12 and is an opening provided for injecting electrolyte during the manufacturing process of the battery 100. The injection hole 15 is sealed by a sealing member 16. As such, a blind rivet is preferably preferred. This allows the sealing member 16 to be securely fixed inside the battery casing 10.

[0088] Figure 5 This is a schematic perspective view of the electrode assembly 20 mounted on the sealing plate 14. In this embodiment, a plurality of (here, three) electrode bodies 20a, 20b, and 20c are housed inside the battery casing 10. Furthermore, the number of electrode bodies housed inside a single battery casing 10 is not particularly limited; it may be one or more (multiple). Additionally, as... Figure 2 As shown, on one side of the long side direction Y of each electrode body ( Figure 2 The positive current collector 50 is arranged on the left side, and on the other side in the long side direction Y ( Figure 2 The negative current collector 60 is arranged on the right side. Furthermore, the electrode bodies 20a, 20b, and 20c are connected in parallel. However, the electrode bodies 20a, 20b, and 20c can also be connected in series. The electrode body assembly 20 is here supported by an electrode body support 29 (see reference 20a) made of resin sheet material. Figure 3 In the covered state, it is stored inside the outer body 12 of the battery housing 10 by means of winding the shaft WL along the bottom wall 12a.

[0089] Figure 6 It is a schematic three-dimensional view of electrode body 20a. Figure 7 This is a schematic diagram showing the structure of electrode 20a. Furthermore, the following detailed explanation uses electrode 20a as an example, but the same structure can also be used for electrodes 20b and 20c.

[0090] like Figure 7 As shown, the electrode body 20a has a positive electrode 22, a negative electrode 24, and spacers 26. The electrode body 20a is a wound electrode body formed by stacking strip-shaped positive electrodes 22 and strip-shaped negative electrodes 24 separated by two strip-shaped spacers 26 and wound around a winding shaft WL. However, the construction of the electrode body is not limited to the technology disclosed herein. For example, the electrode body can also be a stacked electrode body formed by stacking multiple square-shaped (typically rectangular) positive electrodes and multiple square-shaped (typically rectangular) negative electrodes in an insulated state.

[0091] The electrode body 20a has a flat shape. The electrode body 20a is disposed inside the outer casing 12 with its winding axis WL approximately parallel to the long side direction Y. Specifically, as... Figure 3 As shown, the electrode body 20a has a pair of curved portions (rounded corner portions) 20r facing the bottom wall 12a and the sealing plate 14 of the outer body 12, and a flat portion 20f connecting the pair of curved portions 20r and facing the second side wall 12c of the outer body 12. The flat portion 20f extends along the second side wall 12c.

[0092] like Figure 7 As shown, the positive electrode 22 has a positive current collector 22c and a positive active material layer 22a and a positive protective layer 22p fixed on at least one surface of the positive current collector 22c. However, the positive protective layer 22p is not necessary and can be omitted in other embodiments. The positive current collector 22c is strip-shaped. The positive current collector 22c is made of conductive metals such as aluminum, aluminum alloy, nickel, and stainless steel. The positive current collector 22c is a metal foil, specifically an aluminum foil.

[0093] At one end of the positive current collector 22c along the long side direction Y ( Figure 7 Multiple positive electrode tabs 22t are provided at the left end of the strip. These multiple positive electrode tabs 22t are spaced apart (intermittently) along the length of the strip-shaped positive electrode 22. The multiple positive electrode tabs 22t face one side of the axial direction of the winding shaft WL. Figure 7 The left side of the spacer 26 protrudes outward. Furthermore, the positive electrode tab 22t can also be positioned on the opposite side of the axial direction of the winding shaft WL (if...). Figure 7(This is indicated by the right side), and can also be respectively disposed on both sides of the axial direction of the winding shaft WL. The positive electrode tab 22t is part of the positive electrode current collector 22c and is made of metal foil (aluminum foil). However, the positive electrode tab 22t can also be a component different from the positive electrode current collector 22c. At least a portion of the positive electrode tab 22t has an area where the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed, and the positive electrode current collector 22c is exposed.

[0094] like Figure 4 As shown, multiple positive electrode tabs 22t are located at one end of the winding shaft WL along its axial direction. Figure 4 The left end of each electrode is stacked to form a positive electrode tab assembly 23. Furthermore, multiple positive electrode tabs 22t are connected to the positive current collector 50 in a bent state. This increases the size of the main body of the electrode assembly 20 housed within the battery casing 10, thus enabling a higher energy density battery 100. Figure 2 As shown, the positive electrode tab group 23 is electrically connected to the positive terminal 30 via the positive electrode current collector 50. Specifically, the positive electrode tab group 23 and the positive electrode second current collector 52 are connected at the connection point J (see reference). Figure 4 In some embodiments, the width of the positive current collector 22c in the direction perpendicular to the strip direction (see reference). Figure 7 The current (22V) is, for example, 10cm or more, preferably 20cm or more, and more preferably 25cm or more. The same applies to the negative current collector 24c.

[0095] Furthermore, the second positive current collector 52 is electrically connected to the positive terminal 30 via the first positive current collector 51. Additionally, the dimensions of the plurality of positive electrode tabs 22t (length along the long side direction Y and width orthogonal to the long side direction Y, refer to...) Figure 7 The connection state with the positive electrode current collector 50 can be considered, and adjusted appropriately according to its formation position, for example. Here, the dimensions of each of the plurality of positive electrode tabs 22t are different so that the outer ends are aligned when bent. Furthermore, the technology disclosed herein can also be applied to cases where the dimensions of the positive electrode tabs are the same. Additionally, the positive electrode tabs 22t are trapezoidal in shape, but the technology disclosed herein can also be applied to cases where the positive electrode tabs are of other shapes (e.g., rectangular shapes). Furthermore, in some embodiments, when the number of layers of the positive electrode in the wound electrode body is set to M, and the number of positive electrode tabs on the positive electrode is set to N, the ratio (N / M) is, for example, 0.5 or more, preferably 0.6 or more, more preferably 0.8 or more, and even more preferably 0.9 or more (or 1). The same applies to the corresponding portion of the negative electrode. Furthermore, M is preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more.

[0096] like Figure 7As shown, the positive electrode active material layer 22a is arranged in a strip shape along the length direction of the strip-shaped positive electrode current collector 22c. The positive electrode active material layer 22a contains a positive electrode active material (e.g., a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide) capable of reversibly attracting and releasing charge carriers. When the total solid content of the positive electrode active material layer 22a is set to 100% by mass, the positive electrode active material can account for approximately 80% by mass or more, typically 90% by mass or more, for example, 95% by mass or more. The positive electrode active material layer 22a may also contain any components other than the positive electrode active material, such as conductive materials, binders, various additives, etc. As a conductive material, carbon materials such as acetylene black (AB) can be used, for example. As a binder, polyvinylidene fluoride (PVdF) can be used, for example.

[0097] like Figure 7 As shown, the positive electrode protective layer 22p is disposed at the interface between the positive electrode current collector 22c and the positive electrode active material layer 22a in the long side direction Y. The positive electrode protective layer 22p is disposed at one end of the winding shaft WL of the positive electrode current collector 22c along its axial direction. Figure 7 (At the left end). However, the positive electrode protective layer 22p can also be disposed at both ends in the axial direction. The positive electrode protective layer 22p is disposed in a strip shape along the positive electrode active material layer 22a. The positive electrode protective layer 22p contains inorganic filler (e.g., alumina). When the total solid composition of the positive electrode protective layer 22p is set to 100% by mass, the inorganic filler can account for approximately 50% by mass or more, typically 70% by mass or more, for example, 80% by mass or more. The positive electrode protective layer 22p can also contain any component other than the inorganic filler, such as conductive materials, binders, various additives, etc. The conductive materials and binders can also be the same as those exemplified as materials that can be contained in the positive electrode active material layer 22a.

[0098] like Figure 7 As shown, the negative electrode 24 has a negative electrode current collector 24c and a negative electrode active material layer 24a fixed on at least one surface of the negative electrode current collector 24c. The negative electrode current collector 24c is strip-shaped. The negative electrode current collector 24c is made of conductive metals such as copper, copper alloy, nickel, and stainless steel. The negative electrode current collector 24c is a metal foil, specifically a copper foil.

[0099] At one end of the axial direction of the winding shaft WL of the negative current collector 24c ( Figure 7 Multiple negative electrode tabs 24t are provided at the right end of the strip. These multiple negative electrode tabs 24t are spaced apart (intermittently) along the length of the strip-shaped negative electrode 24. The multiple negative electrode tabs 24t are respectively oriented towards one side of the axial direction. Figure 7 The right side of the spacer 26 protrudes outward. However, the negative electrode tab 24t can also be located at the other end in the axial direction. Figure 7The negative electrode tab 24t can be located at either end of the negative electrode current collector 24c, or at either end of the axial direction. The negative electrode tab 24t is part of the negative electrode current collector 24c and is made of metal foil (copper foil). However, the negative electrode tab 24t can also be a different component from the negative electrode current collector 24c. At least a portion of the negative electrode tab 24t has an area where the negative electrode active material layer 24a is not formed, exposing the negative electrode current collector 24c.

[0100] like Figure 4 As shown, multiple negative electrode tabs 24t are located at one end in the axial direction ( Figure 4 The negative electrode tabs 25 are formed by stacking the right end of the electrode assembly 23. The negative electrode tabs 25 are preferably positioned symmetrically to the positive electrode tabs 23 in the axial direction. Furthermore, multiple negative electrode tabs 24t are connected to the negative current collector 60 in a bent state. This increases the size of the main body of the electrode assembly 20 housed within the battery casing 10, thus enabling a higher energy density battery 100. Figure 2 As shown, the negative electrode tab assembly 25 is electrically connected to the negative terminal 40 via the negative electrode current collector 60. Specifically, the negative electrode tab assembly 25 and the negative electrode second current collector 62 are connected at the connection point J (see reference). Figure 4 Furthermore, the second negative current collector 62 is electrically connected to the negative terminal 40 via the first negative current collector 61. Similar to the plurality of positive electrode tabs 22t, the plurality of negative electrode tabs 24t are each of different dimensions to ensure alignment of their outer ends when bent. Furthermore, the technology disclosed herein can also be applied to cases where the negative electrode tabs are of the same size. Additionally, the negative electrode tabs 24t are trapezoidal in shape, but the technology disclosed herein can also be applied to cases where the negative electrode tabs are of other shapes (e.g., rectangular shapes).

[0101] like Figure 7 As shown, the negative electrode active material layer 24a is arranged in a strip shape along the length direction of the strip-shaped negative electrode current collector 24c. The negative electrode active material layer 24a contains a negative electrode active material (e.g., carbon material such as graphite) capable of reversibly adsorbing and releasing charge carriers. When the total solid composition of the negative electrode active material layer 24a is set to 100% by mass, the negative electrode active material can account for approximately 80% by mass or more, typically 90% by mass or more, for example, 95% by mass or more. The negative electrode active material layer 24a may also contain any components other than the negative electrode active material, such as binders, dispersants, various additives, etc. As a binder, rubbers such as styrene-butadiene rubber (SBR) can be used, for example. As a dispersant, cellulose-based materials such as carboxymethyl cellulose (CMC) can be used, for example.

[0102] like Figure 7As shown, spacer 26 is a component that insulates the positive electrode active material layer 22a of the positive electrode 22 from the negative electrode active material layer 24a of the negative electrode 24. As spacer 26, a porous sheet made of resin such as polyethylene (PE) or polypropylene (PP) is preferably preferred. Spacer 26 may also have a substrate portion made of a porous resin sheet and a heat resistance layer (HRL) containing inorganic fillers disposed on at least one surface of the substrate portion. Examples of inorganic fillers include alumina, boehmite, aluminum hydroxide, and titanium dioxide.

[0103] The electrolyte can be the same as before, without any particular restrictions. For example, the electrolyte may be a non-aqueous electrolyte containing a non-aqueous solvent and a supporting salt. Non-aqueous solvents include carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Supporting salts may be fluorinated lithium salts such as LiPF6. However, the electrolyte may also be in solid form (solid electrolyte) and integrated with the electrode assembly 20.

[0104] like Figure 2 As shown, the positive terminal 30 is inserted into one end of the sealing plate 14 in the Y direction along its long side. Figure 2 The positive terminal 30 is inserted into the terminal insertion hole 18 at the left end of the sealing plate 14. The positive terminal 30 is preferably made of metal, more preferably of, for example, aluminum or an aluminum alloy. On the other hand, the negative terminal 40 is inserted into the end formed on the other side of the long side in the Y direction of the sealing plate 14. Figure 2 The positive terminal 30 and negative terminal 40 are inserted into the terminal insertion holes 19 at the right end of the battery housing 10. Furthermore, the negative terminal 40 is preferably made of metal, more preferably of copper or a copper alloy. These electrode terminals (positive terminal 30, negative terminal 40) protrude from the same side of the battery housing 10 (specifically, the sealing plate 14). However, the positive terminal 30 and negative terminal 40 may also protrude from different sides of the battery housing 10. Additionally, the electrode terminals (positive terminal 30, negative terminal 40) inserted into the terminal insertion holes 18, 19 are preferably fixed to the sealing plate 14 by riveting or the like.

[0105] As mentioned above, such as Figure 2 As shown, the positive terminal 30 is located inside the outer casing 12 via the positive current collector 50 (positive first current collector 51, positive second current collector 52) and the positive terminals 22 of each electrode body (see reference). Figure 7Electrical connection. The positive terminal 30 is insulated from the sealing plate 14 by the positive internal insulating member 70 and the gasket 90. Furthermore, the positive internal insulating member 70 has a base 70a located between the positive first current collector 51 and the sealing plate 14, and a protrusion 70b protruding from the base 70a toward the electrode assembly 20. Moreover, the positive terminal 30, which protrudes to the outside of the battery casing 10 through the terminal insertion hole 18, is connected to the positive external conductive member 32 outside the sealing plate 14. On the other hand, as... Figure 2 As shown, the negative terminal 40 is connected inside the outer casing 12 to the negative terminals 24 of each electrode body (see reference 60) via the negative current collector 60 (the first negative current collector 61 and the second negative current collector 62). Figure 7 Electrical connection. The negative terminal 40 is insulated from the sealing plate 14 by the negative internal insulating member 80 and the gasket 90. Furthermore, similar to the positive internal insulating member 70, the negative internal insulating member 80 also has a base 80a located between the negative first current collector 61 and the sealing plate 14, and a protrusion 80b protruding from the base 80a toward the electrode assembly 20. Moreover, the negative terminal 40, which protrudes to the outside of the battery casing 10 through the terminal insertion hole 19, is connected to the negative external conductive member 42 outside the sealing plate 14. Furthermore, an external insulating member 92 is sandwiched between the aforementioned external conductive members (positive external conductive member 32, negative external conductive member 42) and the outer surface of the sealing plate 14. This external insulating member 92 can insulate the external conductive members 32 and 42 from the sealing plate 14. Furthermore, the protrusions 70b and 80b of the aforementioned internal insulating members (positive electrode internal insulating member 70 and negative electrode internal insulating member 80) are disposed between the sealing plate 14 and the electrode assembly 20. These protrusions 70b and 80b of the internal insulating members restrict the upward movement of the electrode assembly 20, preventing contact between the sealing plate 14 and the electrode assembly 20.

[0106] Below, refer to Figure 8A and Figure 8B The configuration of the positive electrode side end face of the electrode body 20a in this embodiment will be described. Furthermore, for ease of explanation, descriptions of components other than the positive electrode are omitted. First, regarding... Figure 8A and Figure 8B The various constituent elements will be explained. Furthermore, in Figure 8A and Figure 8B For ease of explanation, only the four positive electrode tabs 22t of interest in this study are described among the multiple positive electrode tabs 22t of the electrode body 20a (specifically, the first tab 22t1, the second tab 22t2, the third tab 22t3, and the fourth tab 22t4). In other words, the electrode body 20a, besides... Figure 8A and Figure 8BIn addition to the described positive electrode tab 22t, the electrode body 20a has multiple other tabs. The electrode body 20a has a first region P located on one side of the winding shaft WL and a second region Q located on the other side of the winding shaft WL in its thickness direction X (in other words, the stacking direction of the electrode body 20a). Furthermore, the first tab 22t1, within the positive electrode tab 22t located in the first region P, is located at the position closest to the winding shaft WL in the thickness direction X (the innermost circumference), and the second tab 22t2, within the positive electrode tab 22t located in the second region Q, is located at the position closest to the winding shaft WL in the thickness direction X (the innermost circumference). Furthermore, the third tab 22t3, located in the positive tab 22t of the first region P, is situated at the position furthest from the winding axis WL in the thickness direction X (outermost periphery), and the fourth tab 22t4, located in the positive tab 22t of the second region Q, is situated at the position furthest from the winding axis WL in the thickness direction X (outermost periphery). Moreover, the distance between the center C1 of the root width of the first tab 22t1 and the center C2 of the root width of the second tab 22t2 in the vertical direction Z relative to the thickness direction X is defined as G1, and the distance between the center C3 of the root width of the third tab 22t3 and the center C4 of the root width of the fourth tab 22t4 in the same vertical direction Z is defined as G2. Additionally, the root width of the positive tab 22t refers to the width of the boundary between the positive current collector 22c (the main body portion) and the positive tab 22t. Figure 7 (22w). The root width of the negative electrode tab 24t also refers to the corresponding part of the negative electrode 24.

[0107] like Figure 8A As shown, on the positive electrode side end face of the electrode body 20a in this embodiment, the center C1 of the root width of the first tab 22t1 and the center C3 of the root width of the third tab 22t3 are offset in the vertical direction Z, and the center C2 of the root width of the second tab 22t2 and the center C4 of the root width of the fourth tab 22t4 are also offset in the vertical direction Z. With this structure, it is possible to appropriately confirm whether the tabs near the innermost periphery where tab bending is likely to occur (here, the first tab 22t1 and the second tab 22t2) have bent. Furthermore, by selecting and using an electrode body with tabs that have not bent, a highly reliable battery with multiple tabs stably connected to the current collector can be obtained.

[0108] like Figure 8B As shown, in this embodiment, when the distance between center C1 and center C2 in the vertical direction Z is set as G1, and the distance between center C3 and center C4 in the vertical direction Z is set as G2, G1 and G2 satisfy the relationship G1 > G2.

[0109] like Figure 8AAs shown, in this embodiment, the starting end 27 of the positive electrode 22 is located in the first region P. Furthermore, in the vertical direction Z, the center C1 is located at a position farther from the winding axis WL than the center C2. Additionally, in this embodiment, the ending end 28 of the positive electrode 22 is disposed at the bend 20r of the electrode body 20a. Furthermore, as... Figure 8A As shown, in this embodiment, centers C3 and C4 are located on the side of the sealing plate 14 closer to the winding shaft WL. However, this is not intended to be limited to these structures.

[0110] like Figure 8B As shown, in this embodiment, when the straight line passing through centers C1 and C3 is designated as the first straight line L1, and the straight line passing through centers C2 and C4 is designated as the second straight line L2, the first straight line L1 and the second straight line L2 are inclined relative to the thickness direction X. Furthermore, in the vertical direction Z, the first straight line L1 and the second straight line L2 are not on the same straight line. Moreover, the first straight line L1 and the second straight line L2 are inclined in the same direction in the thickness direction X. Here, there are no particular limitations on the values ​​of the angles θa and θb between straight line L1 and the thickness direction X, as long as the effect of the disclosed technology is achieved. On the other hand, from the viewpoint that it is easier to confirm the tab bending of the innermost tabs (here, the first tab 22t1 and the second tab 22t2), larger angles θa and θb are more preferable. Angles θa and θb are, for example, 15° or more, preferably 30° or more, more preferably 45° or more (the upper limit can be, for example, 70°). The values ​​of angles θa and θb can be the same or different. Furthermore, the same applies to the second to seventh embodiments described later. This angle can be measured, for example, using an image measuring machine or the like.

[0111] Although detailed details are not illustrated, in this embodiment, multiple positive electrode tabs 22t are connected to the positive electrode current collector 50 in a foil-like manner, with the first tab 22t1 being closer to the positive electrode current collector 50 than the third tab 22t3. Furthermore, the length of the third tab 22t3 in the protruding direction is greater than the length of the first tab 22t1 in the protruding direction, and the length of the fourth tab 22t4 in the protruding direction is smaller than the length of the second tab 22t2 in the protruding direction. Here, the length in the protruding direction of the positive electrode tab 22t refers to the shortest distance from the root of the positive electrode tab 22t to its front end in the protruding direction (i.e., the Y direction). Figure 7 (22z). Furthermore, regarding the negative electrode 24, this also refers to the corresponding portion. Additionally, the root width of the third electrode tab 22t3 is greater than the root width of the first electrode tab 22t1, and the root width of the fourth electrode tab 22t4 is smaller than the root width of the second electrode tab 22t2.

[0112] In some embodiments, the value of G2 is, for example, 15 mm or less, preferably 12 mm or less, more preferably 5 mm or less, and even more preferably 2 mm or less (e.g., 1 mm or less). Additionally, in some embodiments, the value of G1 is, for example, 20 mm or less, preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less. Furthermore, the values ​​of G1 and G2 can be measured, for example, using a ruler or the like. The same applies to G3, which will be described later.

[0113] <Battery Manufacturing Method>

[0114] Next, an example of the battery manufacturing method according to this embodiment will be described. The battery 100 can be manufactured by preparing the battery casing 10 (outer body 12 and sealing plate 14), electrode assembly 20 (electrode bodies 20a, 20b, 20c), electrolyte, positive terminal 30, negative terminal 40, positive electrode current collector 50 (positive electrode first current collector 51 and positive electrode second current collector 52), negative electrode current collector 60 (negative electrode first current collector 61 and negative electrode second current collector 62), and positive electrode internal insulation member 70 and negative electrode internal insulation member 80, for example, by a manufacturing method including a first mounting step, a second mounting step, an insertion step, and a sealing step. Furthermore, the manufacturing method disclosed herein may also include other steps at any stage.

[0115] In the first installation process, the following is made: Figure 9 , Figure 10 The first composite assembly shown. Specifically, firstly, a positive terminal 30, a positive first current collector 51, a positive internal insulating member 70, a negative terminal 40, a negative first current collector 61, and a negative internal insulating member 80 are installed on the sealing plate 14.

[0116] The positive terminal 30, the first positive current collector 51, and the internal positive insulating member 70 are fixed to the sealing plate 14, for example, by riveting. The riveting is performed by inserting a gasket 90 between the outer surface of the sealing plate 14 and the positive terminal 30, and by inserting the internal positive insulating member 70 between the inner surface of the sealing plate 14 and the first positive current collector 51. Furthermore, the material of the gasket 90 can be the same as that of the internal positive insulating member 70. Specifically, before riveting, the positive terminal 30 is inserted sequentially from above the sealing plate 14 into the through hole of the gasket 90, the terminal insertion hole 18 of the sealing plate 14, the through hole of the internal positive insulating member 70, and the through hole 51h of the first positive current collector 51, so that it protrudes below the sealing plate 14. Then, the portion of the positive terminal 30 that protrudes downwards from the sealing plate 14 is riveted to apply a compressive force relative to the vertical direction Z. Therefore, at the front end of the positive terminal 30 ( Figure 2 The lower end of the part forms a riveting part.

[0117] Through this riveting process, the gasket 90, sealing plate 14, positive electrode internal insulation component 70, and positive electrode first current collector 51 are integrally fixed to the sealing plate 14, and the terminal insertion hole 18 is sealed. Furthermore, the riveted portion can also be welded to the positive electrode first current collector 51. This further improves conductivity reliability.

[0118] The negative terminal 40, the first negative current collector 61, and the internal negative insulating member 80 can be fixed in the same manner as the positive terminal side described above. That is, before riveting, the negative terminal 40 is inserted sequentially from above the sealing plate 14 into the through hole of the gasket, the terminal insertion hole 19 of the sealing plate 14, the through hole of the internal negative insulating member 80, and the through hole 61h of the first negative current collector 61, so that it protrudes below the sealing plate 14. Then, the portion of the negative terminal 40 that protrudes downwards from the sealing plate 14 is riveted to apply a compressive force relative to the vertical direction Z. Thus, at the front end of the negative terminal 40 ( Figure 2 The lower end of the part forms a riveting part.

[0119] Next, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 are installed on the outer surface of the sealing plate 14 via the external insulating member 92. Furthermore, the material of the external insulating member 92 can be the same as that of the positive electrode internal insulating member 70. Additionally, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 can be installed after the insertion process (e.g., after sealing the injection hole 15).

[0120] Next, prepare electrode bodies 20a, 20b, and 20c. Specifically, first, prepare the elongated spacer 26 and the positive electrode 22 (refer to...). Figure 11A ) and negative electrode 24 (refer to) Figure 11B Then, as Figure 12 As shown, the spacer 26, positive electrode 22, and negative electrode 24 prepared above are conveyed to the winding core 201 using the conveyor roller 202, and wound around the winding core 201 to form the wound body 200. A cylindrical winding core 201 is used here, but it is not limited to this; for example, a flat winding core can also be used. The individual sheets are wound such that only the positive electrode tab 22t of the positive electrode 22 is positioned from one side of the width direction Y (…). Figure 7 The left side of the middle) protrudes, and only the negative electrode tab 24t of the negative electrode 24 protrudes from the other side ( Figure 7 The right side of the battery 100 protrudes. Furthermore, the number of windings is preferably adjusted appropriately considering the performance and manufacturing efficiency of the battery 100 as desired. In some embodiments, the number of windings can be set to 20 or more, or 30 or more.

[0121] Here, as an example of a method for arranging centers C1 and C3, and centers C2 and C4 at offset positions in the vertical direction Z, a method for adjusting the timing of starting to wind the positive electrode 22 onto the core 201 (hereinafter referred to as "winding timing") can be listed. Furthermore, the winding timing varies depending on the type of winding apparatus used and the dimensions of the spacers, positive electrode, and negative electrode, etc. Therefore, those skilled in the art can determine the winding timing by appropriately conducting preliminary tests, etc. Additionally, for example, when stamping the wound body in the forming process described later, the adjustment can also be made by changing the position where the wound body is flattened. Alternatively, the adjustment can also be made by changing the spacing in the length direction of the multiple positive electrode tabs or by changing the tension applied to the positive electrode when winding it onto the core. Furthermore, these methods can be appropriately combined for adjustment. On the other hand, among the methods listed above, from the viewpoint of making changes more easily and with better reproducibility, the method of adjusting the timing of winding the positive electrode onto the core and changing the position where the wound body is flattened during stamping are preferred.

[0122] Next, the aforementioned wound body 200 is shaped into a flat shape. Specifically, in this embodiment, as shown in... Figure 13A After the wound body is mounted on the stamping press 204 shown, stamping is performed in the direction of the hollow arrow to obtain the product shown. Figure 13B The flat, wound electrode body (electrode body 20a) is shown. Here, the stamping pressure is preferably adjusted appropriately according to the number of turns, size, etc., of the wound body. For example... Figure 3 As shown, the flat-shaped wound electrode body after stamping has a pair of curved portions 20r with a bent outer surface and a flat portion 20f connecting the pair of curved portions 20r with a flat outer surface. Additionally, as... Figure 7 As shown, a positive electrode tab 23, formed by stacking positive electrode tabs 22t, is formed at one end of the flat, rolled electrode body in the width direction Y after stamping, and a negative electrode tab 25, formed by stacking negative electrode tabs 24t, is formed at the other end. Furthermore, a core portion is formed at the center of the rolled electrode body in the width direction Y, with the positive electrode active material layer 22a and the negative electrode active material layer 24a facing each other. Additionally, by stamping, the surface layer of the spacer 26 can be bonded to the positive electrode 22 (negative electrode 24).

[0123] Furthermore, in this embodiment, a spacer 26 is disposed on the outermost circumferential surface of the stamped wound electrode body (electrode body 20a), and a winding fixing tape is attached to the end of the spacer 26 at the end of the winding to maintain the shape of the wound electrode body. As the winding fixing tape, conventionally known winding fixing tapes used for wound electrode bodies can be used without particular limitation. Furthermore, as... Figure 8AAs shown, in this embodiment, the end 28 of the positive electrode 22 at the end of its winding is disposed in the bent portion 20r of the electrode body 20a. As described above, electrode bodies 20a, 20b, and 20c of this embodiment can be manufactured.

[0124] In the second installation step, the first assembly produced in the first installation step is used to create a product as follows: Figure 5 The second assembly shown is the electrode assembly 20, which is integrated with the sealing plate 14. Specifically, firstly, as shown... Figure 6 As shown, three electrode bodies 20a, each equipped with a positive second current collector 52 and a negative second current collector 62, are prepared and designated as electrode bodies 20a, 20b, and 20c, arranged in the short-side direction X. Alternatively, electrode bodies 20a, 20b, and 20c can all be arranged with the positive second current collector 52 on one side of the long-side direction Y. Figure 5 (Left side), the negative electrode second current collector 62 is disposed on the other side in the long side direction Y ( Figure 5 They are arranged side by side on the right side.

[0125] Then, in such Figure 4 With the multiple positive electrode tabs 22t bent as shown, the first positive electrode current collector 51 fixed to the sealing plate 14 and the second positive electrode current collector 52 of the electrode bodies 20a, 20b, and 20c are respectively joined. Similarly, with the multiple negative electrode tabs 24t bent, the first negative electrode current collector 61 fixed to the sealing plate 14 and the second negative electrode current collector 62 of the electrode bodies 20a, 20b, and 20c are respectively joined. As a joining method, welding methods such as ultrasonic welding, resistance welding, and laser welding can be used. Welding using high-energy rays such as lasers is particularly preferred. Through this welding process, joint portions are formed in the recesses of the second positive electrode current collector 52 and the second negative electrode current collector 62, respectively.

[0126] In the insertion process, the second assembly, manufactured in the second installation process, is housed within the internal space of the outer casing 12. Specifically, firstly, for example, an insulating resin sheet made of a resin material such as polyethylene (PE) is bent into a bag or box shape to prepare an electrode holder 29. Next, the electrode assembly 20 is housed within the electrode holder 29. Then, the electrode assembly 20, covered by the electrode holder 29, is inserted into the outer casing 12. If the electrode assembly 20 is relatively heavy, approximately 1 kg or more, for example, 1.5 kg or more, or even 2 to 3 kg, the electrode assembly 20 can be inserted into the outer casing 12 in a configuration where the long sidewall 12b of the outer casing 12 is perpendicular to the direction of gravity (by placing the outer casing 12 on its side).

[0127] In the sealing process, the opening 12h of the outer casing 12 is sealed by joining the sealing plate 14 to the edge. The sealing process can be performed simultaneously with or after the insertion process. In the sealing process, it is preferable to weld the outer casing 12 to the sealing plate 14. The welding of the outer casing 12 to the sealing plate 14 can be performed, for example, by laser welding. Afterward, electrolyte is injected through the injection hole 15, and the injection hole 15 is blocked by the sealing member 16, thereby sealing the battery 100. In this way, the battery 100 can be manufactured.

[0128] The battery 100 can be used for various purposes, but is preferably used in applications where external forces such as vibration and impact may be applied during use. For example, it is preferably used as a power source (drive power source) for an electric motor mounted on a moving body (typically a passenger car, truck, or other vehicle). There is no particular limitation on the type of vehicle; examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs). The battery 100 can also preferably be used as a battery pack formed by arranging multiple batteries 100 in a predetermined arrangement direction and applying a load from the arrangement direction using a constraint mechanism.

[0129] The present invention has been described above with reference to several embodiments, but these embodiments are merely examples. The present invention can be implemented in various other ways. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field. The technology described in the claims includes technologies obtained by various modifications and alterations to the embodiments illustrated above. For example, a portion of the above embodiments can be replaced with other modifications, and other modifications can be added to the above embodiments. Furthermore, if a technical feature is not described as an essential technical feature, it can be appropriately deleted.

[0130] For example, Figure 14 This is a schematic diagram showing one end face of the positive electrode side of the electrode body 120a in the second embodiment. (See diagram below.) Figure 14 As shown, in the second embodiment, center C3 and center C4 are located on approximately a straight line in the thickness direction X, and center C1 and center C2 are located at offset positions in the vertical direction Z.

[0131] For example, Figure 15 This is a schematic diagram showing one end face of the positive electrode side of the electrode body 220a in the third embodiment. (See diagram below.) Figure 15 As shown, in the third embodiment, center C1 and center C2 are approximately on a straight line in the thickness direction X, and center C3 and center C4 are at offset positions in the vertical direction Z.

[0132] For example, Figure 16This is a schematic diagram showing one end face of the positive electrode side of the electrode body 320a according to the fourth embodiment. Figure 16 As shown, in the fourth embodiment, center C1 and center C2 are located on approximately a straight line in the thickness direction X, and center C3 and center C4 are located at offset positions in the vertical direction Z.

[0133] For example, Figure 17 This is a schematic diagram showing one end face of the positive electrode side of the electrode body 420a in the fifth embodiment. (See diagram below.) Figure 17 As shown, in the fifth embodiment, centers C1, C2, C3, and C4 exist at offset positions in the vertical direction Z.

[0134] For example, Figure 18 This is a schematic diagram showing one end face of the positive electrode side of the electrode body 520a according to the sixth embodiment. (See diagram below.) Figure 18 As shown, in the sixth embodiment, centers C1, C2, C3, and C4 exist at offset positions in the vertical direction Z.

[0135] in addition, Figure 19 This is a schematic diagram showing one end face of the positive electrode side of the electrode body 620a according to the seventh embodiment. (See diagram below.) Figure 19 As shown, in the electrode body 620a, the positive electrode 22 has a fifth tab 22t5 between the first tab 22t1 and the third tab 22t3, and a sixth tab 22t6 between the second tab 22t2 and the fourth tab 22t4 in the thickness direction X. Furthermore, when the center of the root width of the fifth tab 22t5 is set to C5, and the center of the root width of the sixth tab 22t6 is set to C6, the G3 of the centers C5 and C6 in the vertical direction Z is adjusted to G2 < G3 < G1. According to this structure, it is possible to more appropriately confirm whether the tabs near the innermost periphery where tab bending is likely to occur (here, the first tab 22t1 and the second tab 22t2) bend.

[0136] Furthermore, the electrode bodies of the second to seventh embodiments described above can be manufactured using the same manufacturing method as the electrode body of the first embodiment described above. Additionally, the second to sixth embodiments described above may also include a fifth and sixth electrode tab, as in the seventh embodiment.

[0137] For example, in the above embodiments, the technology disclosed herein is applied only to the positive electrode side of the wound electrode body, but is not limited thereto. The technology disclosed herein may also be applied only to the negative electrode side of the wound electrode body, or it may be applied to both the positive and negative electrode sides of the wound electrode body. Furthermore, regarding the negative electrode side of the wound electrode body, the position of the negative electrode tab can be changed based on the description of the positive electrode side.

[0138] For example, when the battery includes two electrodes, the values ​​of G1 and G2 of the two electrodes can be different. Furthermore, in some embodiments, the G1 of one electrode can be greater than the G1 of the other electrode. Moreover, in some embodiments, the difference between the G1 of one electrode and the G1 of the other electrode can be greater than the difference between the G2 of one electrode and the G2 of the other electrode.

[0139] For example, the battery also includes another electrode body, namely a third electrode body, whose G1 may be different from the G1 of one electrode body and the G1 of the other electrode body, and whose G2 may be different from the G2 of one electrode body and the G2 of the other electrode body.

[0140] The embodiments of the technology disclosed herein have been described above. However, the above description is merely illustrative and does not limit the scope of the claims. The technology described in the claims includes technologies obtained by various modifications and alterations to the specific examples illustrated in the above description.

Claims

1. A battery, said battery comprising: A flat, wound electrode body formed by winding a first electrode and a second electrode of different polarity with respect to the first electrode, separated by a spacer; and A battery casing for housing the wound electrode body. in, Multiple tabs connected to the first electrode protrude from one end of the wound electrode body in the direction of the winding axis. The plurality of tabs are connected to the current collector of the first electrode. The wound electrode body has a first region located on one side of the winding shaft and a second region located on the other side of the winding shaft in the thickness direction of the wound electrode body. The plurality of electrodes includes a first electrode, a second electrode, a third electrode, and a fourth electrode. The first tab, within the tabs present in the first region, is located at the position closest to the winding axis of the wound electrode body in the thickness direction. The second tab, within the tab present in the second region, is located at the position closest to the winding axis of the wound electrode body in the thickness direction. The third tab, among the tabs present in the first region, is located at the position furthest from the winding axis of the wound electrode body in the thickness direction. The fourth tab, among the tabs present in the second region, is located at the position furthest from the winding axis of the wound electrode body in the thickness direction. At the end of one of them, The center C1 of the root width of the first electrode and the center C3 of the root width of the third electrode are configured in an offset state in the direction perpendicular to the thickness direction. The center C2 of the root width of the second electrode and the center C4 of the root width of the fourth electrode are configured in an offset state in the vertical direction.

2. The battery according to claim 1, wherein, Let G1 be the distance between the center C1 and the center C2 in the vertical direction. When the distance between the center C3 and the center C4 in the vertical direction is set to G2, G1 and G2 satisfy the relationship G1 > G2.

3. The battery according to claim 1 or 2, wherein, The end at which the first electrode begins to be wound exists in the first region. In the vertical direction, the center C1 is located at a position farther away from the winding axis of the winding electrode than the center C2.

4. The battery according to claim 1 or 2, wherein, The battery casing includes: An outer casing having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall; as well as A sealing plate that seals the opening. The wound electrode body is arranged such that the winding axis runs along the bottom wall. The center C3 and the center C4 are located on the sealing plate side, which is closer to the winding shaft.

5. The battery according to claim 2, wherein, The wound electrode body also has a fifth tab and a sixth tab on the first electrode. The fifth electrode tab is disposed between the first electrode tab and the third electrode tab in the thickness direction. The sixth electrode tab is disposed between the second electrode tab and the fourth electrode tab in the thickness direction. At the end of one of them, When the center of the root width of the fifth electrode ear is set as center C5, the center of the root width of the sixth electrode ear is set as center C6, and the distance between the center C5 and the center C6 in the vertical direction is set as G3, G1, G2, and G3 satisfy the relationship G2 < G3 < G1.

6. The battery according to claim 1 or 2, wherein, The straight line passing through the center C1 and the center C3 is designated as the first straight line. When the straight line passing through the center C2 and the center C4 is designated as the second straight line... The first straight line and the second straight line are inclined relative to the thickness direction.

7. The battery according to claim 6, wherein, In the vertical direction, the first straight line and the second straight line do not lie on the same straight line.

8. The battery according to claim 6, wherein, The first straight line and the second straight line are inclined in the same direction in the thickness direction.

9. The battery according to claim 1 or 2, wherein, The plurality of tabs are connected to the current collector of the first electrode in a foil-like manner. The first electrode tab is closer to the current collector of the first electrode than the third electrode tab. The length of the third electrode in the protruding direction is greater than the length of the first electrode in the protruding direction. The length of the fourth electrode in the protruding direction is smaller than the length of the second electrode in the protruding direction.

10. The battery according to claim 1 or 2, wherein, The plurality of tabs are connected to the current collector of the first electrode in a foil-like manner. The first electrode tab is closer to the current collector of the first electrode than the third electrode tab. At one end of the winding axis of the wound electrode body, The root width of the third electrode tab is greater than the root width of the first electrode tab. The root width of the fourth electrode tab is smaller than the root width of the second electrode tab.

11. The battery according to claim 1 or 2, wherein, The plurality of tabs are connected to the first electrode current collector in a bent state.

12. The battery according to claim 1 or 2, wherein, The winding electrode body has a pair of end faces with flat portions and a pair of curved portions disposed at both ends of the flat portions, and the end of the first electrode at the end of winding is disposed in the curved portions.

13. The battery according to claim 1 or 2, wherein, Multiple second electrode tabs connected to the second electrode protrude from the opposite end in the winding axis direction of the wound electrode body.

14. The battery according to claim 2, wherein, Two of the wound electrode bodies are disposed inside the battery casing. The values ​​of G1 of the two wound electrodes are different, and / or the values ​​of G2 of the two wound electrodes are different.

15. The battery according to claim 14, wherein, The G1 of one of the two wound electrode bodies is greater than the G1 of the other wound electrode body.

16. The battery according to claim 14 or 15, wherein, The difference between G1 of one wound electrode and G1 of the other wound electrode is greater than the difference between G2 of one wound electrode and G2 of the other wound electrode.

17. The battery according to claim 14 or 15, wherein, Another wound electrode, namely the third electrode, is also disposed within the battery casing. The G1 of the third electrode is different from the G1 of the wound electrode of one party and the G1 of the wound electrode of the other party, and / or, The G2 of the third electrode is different from the G2 of the wound electrode of one party and the G2 of the wound electrode of the other party.

Images