Wound electrode assembly

Abstract

The present invention relates to a wound electrode body in which a first electrode and a second electrode having a polarity different from that of the first electrode are wound in a flat shape with a separator interposed therebetween. In the wound electrode body, a first electrode includes: a resin substrate; the conductive layer is arranged on the surface of the resin base material; and a first active material layer provided on the main surface of the conductive layer on the opposite side from the resin substrate side with respect to the conductive layer. The heat dissipation performance of a portion of the resin base material located inside the wound electrode body is higher than the heat dissipation performance of a portion located outside the wound electrode body.

Description

Technical Field

[0001] This disclosure relates to wound electrode bodies. Background Technology

[0002] As a current collector used in conventional wound electrode bodies, Japanese Patent Application Publication No. 2019-186195 discloses a structure having an insulating layer and a conductive layer, and having a plurality of through holes penetrating the insulating layer (resin foil) and the conductive layer in the current collector. Summary of the Invention

[0003] When a sheet electrode with a conductive layer on the surface of a resin foil (resin substrate) and an active material layer coated on the conductive layer is wound to form a wound electrode body, the resin foil has poor heat dissipation compared to a metal foil. Therefore, in the wound electrode body, heat is easily trapped inside the winding.

[0004] This disclosure is made in view of the aforementioned problems, and the purpose of this disclosure is to provide a wound electrode body capable of improving heat dissipation on the inner side of the winding.

[0005] The wound electrode body based on this disclosure is a wound electrode body obtained by winding a first electrode and a second electrode with a polarity different from that of the first electrode into a flat shape with a separator between them. In this wound electrode body, the first electrode includes: a resin substrate; a conductive layer disposed on the surface of the resin substrate; and a first active material layer disposed on the main surface of the conductive layer on the side opposite to the side where the resin substrate is located. The heat dissipation performance of the portion of the resin substrate located on the inner side of the wound electrode body is higher than that of the portion located on the outer side of the wound electrode body.

[0006] According to the above configuration, by making the heat dissipation performance of the portion of the resin substrate located on the inner side of the wound electrode body higher than that of the portion located on the outer side of the wound electrode body, the heat dissipation performance of the inner side of the wound electrode body can be improved.

[0007] In the wound electrode body based on the present disclosure, the heat dissipation of the resin substrate may gradually or gradually increase as it moves toward the inner side of the wound electrode body.

[0008] Based on the above configuration, heat dissipation can be gradually or gradually improved towards the inner side of the wound electrode body.

[0009] In the wound electrode body based on the present disclosure, the resin substrate may be composed of a first resin member and a second resin member with higher heat dissipation than the first resin member. Furthermore, when the direction parallel to the winding axis of the wound electrode body is set as the width direction, the proportion of the second resin member in the width direction increases as it moves towards the inner side of the wound electrode body compared to the proportion of the first resin member in the width direction.

[0010] By adjusting the proportions of the first resin component and the second resin component in the width direction of the resin substrate as described above, the heat dissipation of the inner side of the winding can be improved.

[0011] In the wound electrode body based on the present disclosure described above, the resin substrate may be constructed by laminating a first resin member with a second resin member having a higher heat dissipation capacity than the first resin member. Furthermore, in the resin substrate, the proportion of the second resin member in the thickness direction increases as it moves toward the inner side of the wound electrode body compared to the proportion of the first resin member in the thickness direction.

[0012] By adjusting the proportions of the first resin component and the second resin component in the thickness direction of the resin substrate as described above, the heat dissipation of the inner side of the winding can be improved.

[0013] In the wound electrode body based on the present disclosure, the resin substrate may include an inner end located at one end in the winding direction of the wound electrode body and an outer end located at the other end in the winding direction. The resin substrate may be formed by joining a first resin member located at the outer end to a second resin member located at the inner end and having a higher heat dissipation performance than the first resin member. The proportion of the second resin member arranged along the winding direction may be greater than the proportion of the first resin member arranged along the winding direction.

[0014] By adjusting the ratio of the first resin component and the second resin component along the winding direction as described above, the heat dissipation of the inner side of the winding can be improved.

[0015] In the wound electrode body disclosed herein, the first resin member may be engaged with the second resin member in a state where it is bitten into along the winding direction.

[0016] According to the above configuration, by inserting the first resin member into the second resin member, the bonding between the first resin member and the second resin member can be stabilized.

[0017] In the wound electrode body based on the present disclosure, the second resin component may have self-extinguishing properties.

[0018] Based on the above configuration, the wound electrode body can be made to have a self-extinguishing function, and the flame retardancy of the wound electrode body becomes easier.

[0019] The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description relating to the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a perspective view showing the battery of Embodiment 1.

[0021] Figure 2 This is an exploded perspective view of the battery according to Embodiment 1.

[0022] Figure 3 It is Figure 1 A cross-sectional view of the battery when viewed in the direction of the arrow along line III-III.

[0023] Figure 4 It is Figure 3 A cross-sectional view of the wound electrode body viewed in the direction of the arrow along line IV-IV.

[0024] Figure 5 It is Figure 3 A cross-sectional view of the wound electrode body viewed in the direction of the arrow on line VV.

[0025] Figure 6 It is Figure 3 A schematic cross-sectional view of the wound electrode body when viewed partially in the direction of the arrow along line VI-VI.

[0026] Figure 7 This is the unfolded diagram of the first electrode.

[0027] Figure 8 It is Figure 5 A magnified partial cross-sectional view of region VIII of the first electrode.

[0028] Figure 9 It is Figure 5 A magnified partial cross-sectional view of region IX of the wound electrode body.

[0029] Figure 10 This is a development view of the resin substrate of Embodiment 1.

[0030] Figure 11 This is a development view of the resin substrate of Embodiment 2.

[0031] Figure 12 This is a development diagram of the resin substrate according to Embodiment 3.

[0032] Figure 13This is a development view of the resin substrate of Embodiment 4.

[0033] Figure 14 This is a development diagram of the resin substrate of Embodiment 5. Detailed Implementation

[0034] The current collector and battery of various embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings referred to below, the same or equivalent components are labeled with the same reference numerals.

[0035] (Implementation Method 1)

[0036] Figure 1 This is a perspective view showing the battery according to Embodiment 1. (As shown) Figure 1 As shown, the battery 1 in Embodiment 1 is a so-called prismatic battery. Battery 1 can be a rechargeable secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery. Battery 1 can, for example, be used as a unit included in an energy storage module mounted in an electric vehicle.

[0037] Figure 2 This is an exploded perspective view of the battery according to Embodiment 1. Figure 3 It is Figure 1 A cross-sectional view of the battery when viewed in the direction of the arrow along line III-III. (See image below.) Figures 1-3 As shown, the battery 1 of Embodiment 1 of this disclosure includes a wound electrode body 10, a housing 20, a first external terminal 30A, a second external terminal 30B, a first connecting member 40A, a second connecting member 40B, a first sealing ring 50A, a second sealing ring 50B, a first terminal support portion 60A, a second terminal support portion 60B, an insulating member 70, and a fuse protection portion 80. First, the components of the battery 1 other than the wound electrode body 10 will be described.

[0038] The housing 20 is conductive. The conductive parts of the housing 20 are made of a metal such as aluminum. The housing 20 houses the wound electrode body 10. The housing 20 also houses an electrolyte (not shown).

[0039] The housing 20 includes a housing body 21 and a cover 22. The housing body 21 includes a bottom wall 21a and a peripheral wall 21b rising from the bottom wall 21a.

[0040] The bottom wall 21a includes a bottom body 21aa, a pressure relief valve 21ab, an outer protective membrane 21ac, and an inner protective membrane 21ad. The peripheral wall 21b rises from the bottom body 21aa. The pressure relief valve 21ab is disposed on the bottom body 21aa. The outer protective membrane 21ac covers the pressure relief valve 21ab from the outside. The inner protective membrane 21ad covers the pressure relief valve 21ab from the inside. The bottom body 21aa and the pressure relief valve 21ab are made of metal such as aluminum.

[0041] An opening is formed at the upper end of the peripheral wall 21b. The peripheral wall 21b has a generally rectangular shape when viewed from the opening direction (the normal direction of the opening surface). The opening and the bottom wall 21a are aligned in a first direction D1. The first direction D1 can be the height direction of the battery 1 or the vertical direction. The peripheral wall 21b is made of a metal such as aluminum.

[0042] The cover 22 includes a cover body 22a, a sealing bolt 22b, a bolt cover 22c, and an insulating cover 22d.

[0043] The cover body 22a is joined to the peripheral wall 21b by welding or the like to close the opening of the peripheral wall 21b. A first connecting hole 22aa, a second connecting hole 22ab, and an electrolyte injection hole 22ac are formed in the cover body 22a. The electrolyte injection hole 22ac is a through hole used to inject electrolyte into the casing body 21 during the manufacturing process of the battery 1.

[0044] A sealing plug 22b seals the injection hole 22ac. A plug cover 22c covers the injection hole 22ac and the sealing plug 22b. An insulating cover 22d covers the injection hole 22ac, the sealing plug 22b, and the plug cover 22c.

[0045] The first external terminal 30A and the second external terminal 30B are arranged to be exposed to the outside in the battery 1. The first connecting structural member 40A and the second connecting structural member 40B are conductive. At least a portion of the first connecting structural member 40A and the second connecting structural member 40B is disposed inside the housing 20.

[0046] The first external terminal 30A or the first connecting member 40A is inserted into the first connecting hole 22aa. The first external terminal 30A and the first connecting member 40A are engaged with each other. The first connecting member 40A is engaged with the wound electrode body 10. Thus, the first external terminal 30A is electrically connected to the wound electrode body 10.

[0047] The second external terminal 30B or the second connecting member 40B is inserted into the second connecting hole 22ab. The second external terminal 30B and the second connecting member 40B are engaged with each other. The second connecting member 40B is engaged with the wound electrode body 10. Thus, the second external terminal 30B is electrically connected to the wound electrode body 10.

[0048] Furthermore, in this embodiment, the first external terminal 30A is the positive terminal, and the second external terminal 30B is the negative terminal. The first external terminal 30A and the second external terminal 30B are arranged in the second direction D2. The second direction D2 is a direction orthogonal to the first direction D1.

[0049] A first sealing ring 50A is disposed along the first connecting hole 22aa. The first sealing ring 50A is disposed in the gap between the cover body 22a and the first external terminal 30A, sealing the gap. A second sealing ring 50B is disposed along the second connecting hole 22ab. The second sealing ring 50B is disposed in the gap between the cover body 22a and the second external terminal 30B, sealing the gap. The first sealing ring 50A and the second sealing ring 50B are electrically insulating.

[0050] The first terminal support portion 60A is engaged with the cover body 22a. The first terminal support portion 60A supports the first external terminal 30A from its outer periphery. The first terminal support portion 60A includes a first locking ring 61A and a first covering ring 62A. The first locking ring 61A extends annularly around the first connecting hole 22aa and is directly engaged with the cover body 22a. The first covering ring 62A covers the first locking ring 61A. The first locking ring 61A supports the first external terminal 30A via the first covering ring 62A. The first covering ring 62A is made of a resin member having electrical insulation or weak conductivity.

[0051] The second terminal support portion 60B is engaged with the cover body 22a. The second terminal support portion 60B supports the second external terminal 30B from its outer periphery. The second terminal support portion 60B includes a second locking ring 61B and a second covering ring 62B. The second locking ring 61B extends annularly around the second connecting hole 22ab and is directly engaged with the cover body 22a. The second covering ring 62B covers the second locking ring 61B. The second locking ring 61B supports the second external terminal 30B via the second covering ring 62B. The second covering ring 62B is made of an electrically insulating resin component.

[0052] The insulating member 70 is electrically insulating. The insulating member 70 is disposed between the wound electrode body 10 and the housing 20. The insulating member 70 electrically insulates the wound electrode body 10 and the housing 20 from each other. The insulating member 70 includes an insulating bracket 71, a peripheral insulating portion 72, and a bottom insulating portion 73.

[0053] An insulating bracket 71 is disposed between the wound electrode body 10 and the cover body 22a. The insulating bracket 71 has high rigidity and is in contact with both the wound electrode body 10 and the cover body 22a. Thus, the wound electrode body 10 is fixed to the housing 20 in the first direction D1.

[0054] The peripheral insulating portion 72 is disposed between the wound electrode body 10 and the peripheral wall 21b. The wound electrode body 10 is composed of a film-like component.

[0055] A bottom insulating portion 73 is disposed between the wound electrode body 10 and the bottom wall 21a. The bottom insulating portion 73 is composed of a film-like component. In this embodiment, the bottom insulating portion 73 is bonded to the wound electrode body 10. Furthermore, the bottom insulating portion 73 only covers a portion of the bottom surface of the wound electrode body 10. The detailed configuration of the bottom insulating portion 73 will be described together with the configuration of the wound electrode body 10 described below.

[0056] like Figure 2 As shown, the battery 1 of this embodiment includes a plurality of wound electrode bodies 10. Typically, the battery 1 includes two wound electrode bodies 10. These wound electrode bodies 10 are arranged in a third direction D3. The third direction D3 is orthogonal to both the first direction D1 and the second direction D2. Furthermore, the peripheral insulating portion 72 may integrally cover the plurality of wound electrode bodies 10, thereby fixing these wound electrode bodies 10 to each other. Additionally, in this embodiment, the insulating member 70 includes a plurality of bottom insulating portions 73 corresponding one-to-one with each of the plurality of wound electrode bodies 10.

[0057] Hereinafter, one of the plurality of wound electrode bodies 10 will be described. Furthermore, each of the plurality of wound electrode bodies 10 may have the configuration shown below.

[0058] Figure 4 It is Figure 3 A cross-sectional view of the wound electrode body viewed in the direction of the arrow along line IV-IV. Figure 5 It is Figure 3 A cross-sectional view of the wound electrode body viewed in the direction of the arrow on line VV. Figure 6 It is Figure 3 A schematic cross-sectional view of the wound electrode body when viewed partially along the direction of the arrow on line VI-VI. (See attached image.) Figures 2-6 As shown, the wound electrode body 10 includes a first electrode 11A, a second electrode 11B, a separator 12, and a strip member 13. The wound electrode body 10 is wound such that the first electrode 11A, the second electrode 11B, and the separator 12 are wound around the winding axis Z. Furthermore, in Figures 4-6 In the middle, the separator 12 is schematically shown with a dashed line.

[0059] The first electrode 11A and the second electrode 11B have a sheet-like shape. The wound electrode body 10 is composed of a group of electrode plates formed by winding the first electrode 11A and the second electrode 11B with one or more separators 12 in between.

[0060] In this embodiment, the first electrode 11A is the positive electrode and the second electrode 11B is the negative electrode. However, it is also possible that the first electrode 11A is the negative electrode and the second electrode 11B is the positive electrode.

[0061] A separator 12 is disposed between the first electrode 11A and the second electrode 11B. The separator 12 allows ion exchange between the first electrode 11A and the second electrode 11B while simultaneously separating the two electrodes. The ions are, for example, lithium ions. The separator 12 is electrically insulating.

[0062] Of the first electrode 11A, the second electrode 11B, and the separator 12, the separator 12 is located on the innermost circumferential side centered on the winding axis Z. Conversely, of the first electrode 11A, the second electrode 11B, and the separator 12, the separator 12 is located on the outermost circumferential side centered on the winding axis Z. The outer circumferential end edge of the separator 12 in the winding direction DR is fixed by a strip member 13 disposed on the outer circumferential surface of the separator 12.

[0063] The separator 12 may, for example, comprise a polyolefin resin. The separator 12 may, for example, be substantially composed of a polyolefin resin. The polyolefin resin may, for example, comprise at least one selected from polyethylene (PE) and polypropylene (PP).

[0064] The first electrode 11A includes a first current collector 100A, a first active material layer 200A, a first protective part 300, and a second protective part 400.

[0065] Figure 7 This is the unfolded diagram of the first electrode. That is, in Figure 7 The image shows the state of the first electrode 11A before it was wound up. Figure 8 It is Figure 5 A magnified partial cross-sectional view of region VIII of the first electrode. Figure 9 It is Figure 5 A magnified partial cross-sectional view of region IX of the wound electrode body. (See diagram below.) Figures 5-9 As shown, the first current collector 100A includes a resin substrate 110, a first conductive layer 120, a second conductive layer 130, and a plurality of first tabs 150A.

[0066] The resin substrate 110 is composed of an electrically insulating resin composition. Therefore, the first current collector 100A is a composite current collector composed of conductive and electrically insulating components. Furthermore, the resin substrate 110 is made of a material with higher rigidity than the separator 12. This allows the resin substrate 110 to be relatively thin.

[0067] The resin substrate 110 includes a main body 111 and a plurality of protruding tabs 112. An orthogonal direction DO, orthogonal to the thickness direction DT of the main body 111, is substantially parallel to a first direction D1. That is, the main body 111 extends substantially parallel to the first direction D1. Each of the plurality of protruding tabs 112 protrudes from the main body 111 along the first direction. The plurality of protruding tabs 112 are arranged separately from each other in the winding direction DR. A first tab 150A, described later, is disposed on each of the plurality of protruding tabs 112.

[0068] To reduce the overall thickness of the wound electrode body 10, the thickness of the resin substrate 110 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The thickness of the resin substrate 110 is not particularly limited if it provides the desired rigidity. For example, a thickness of 2 μm or more is acceptable.

[0069] The first conductive layer 120 is in contact with the main body portion 111 on one side in the thickness direction DT. In this embodiment, the first conductive layer 120 is located on the winding axis Z side when viewed from the main body portion 111. In addition, the first conductive layer 120 is in contact with the main body portion 111 on one side in the thickness direction DT, covering the entire surface.

[0070] The second conductive layer 130 is in contact with the main body portion 111 on the other side in the thickness direction DT. In this embodiment, the second conductive layer 130 is located on the side opposite to the winding axis Z when viewed from the main body portion 111. In addition, the second conductive layer 130 is in contact with the main body portion 111 on the other side in the thickness direction DT, covering the entire surface.

[0071] The first conductive layer 120 and the second conductive layer 130 are each made of metal. In this embodiment, the first conductive layer 120 and the second conductive layer 130 are made of a metal containing aluminum. Therefore, the first current collector 100A can be suitable as a positive current collector. Alternatively, the first current collector 100A can also be a negative current collector, and the first conductive layer 120 and the second conductive layer 130 can also be made of a metal containing copper.

[0072] The thickness of the first conductive layer 120 and the thickness of the second conductive layer 130 are thinner than the thickness of the resin substrate 110. To reduce the overall thickness of the wound electrode body 10, the thickness of the first conductive layer 120 and the thickness of the second conductive layer 130 are, for example, 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. To suppress excessive resistance in the first conductive layer 120 and the second conductive layer 130, the thickness of the first conductive layer 120 and the thickness of the second conductive layer 130 are, for example, 0.1 μm or more.

[0073] The first conductive layer 120 and the second conductive layer 130 are provided, for example, by vapor deposition of an aluminum-containing metal onto the main body 111. The first conductive layer 120 and the second conductive layer 130 may each be a film-like component adhered to the main body 111.

[0074] Each of the plurality of first tabs 150A is bonded to the first conductive layer 120 and the second conductive layer 130, for example, by ultrasonic welding. Each of the plurality of first tabs 150A extends from the resin substrate 110 along the protruding direction of the protruding tab 112 protruding from the main body portion 111.

[0075] Multiple first electrode 150A electrodes are arranged in a manner that allows them to be arranged in the third direction D3 (see reference). Figure 5 Multiple first tabs 150A are joined together, for example, by ultrasonic welding. Multiple first tabs 150A are joined to the first connecting member 40A, for example, by ultrasonic welding (see reference). Figure 2 as well as Figure 3 ).

[0076] like Figure 8 As shown, each of the plurality of first tabs 150A includes a first foil portion 151 and a second foil portion 152.

[0077] The first foil portion 151 is located on the opposite side of the resin substrate 110 when viewed from the first conductive layer 120. The first foil portion 151 is bonded to the first conductive layer 120. The second foil portion 152 is located on the opposite side of the resin substrate 110 when viewed from the second conductive layer 130. The second foil portion 152 is bonded to the second conductive layer 130. The second foil portion 152 is also bonded to the first foil portion 151. The above-mentioned components are bonded to each other, for example, by ultrasonic welding.

[0078] Furthermore, in this embodiment, the length of the first foil portion 151 in the orthogonal direction DO, which is orthogonal to the thickness direction DT, is longer than the length of the second foil portion 152 in the orthogonal direction DO. Also, the first foil portion 151 is engaged with the first connecting member 40A, while the second foil portion 152 is not engaged with the first connecting member 40A. However, the shape of the first tab 150A is not limited to this. Either the first foil portion 151 or the second foil portion 152 can be engaged with the first connecting member 40A. The length of the second foil portion 152 in the orthogonal direction DO may also be longer than the length of the first foil portion 151 in the orthogonal direction DO.

[0079] A first active material layer 200A is stacked on a first conductive layer 120. The first active material layer 200A is a positive electrode active material layer, but it can also be a negative electrode active material layer. In this embodiment, the first active material layer 200A is also stacked on a second conductive layer 130. The first active material layer 200A includes a first inner active material layer 210A and a first outer active material layer 220A. The first inner active material layer 210A is stacked on the first conductive layer 120. The first outer active material layer 220A is stacked on the second conductive layer 130.

[0080] The upper edge of the first active material layer 200A is isolated from each of the plurality of first tabs 150A. The upper edge of the first inner active material layer 210A is isolated from the first foil portion 151 of each of the plurality of first tabs 150A. The upper edge of the first outer active material layer 220A is isolated from the second foil portion 152 of each of the plurality of first tabs 150A.

[0081] like Figure 9 As shown, the lower edge of the first active material layer 200A is parallel to the lower edge of the main body 111.

[0082] Furthermore, the separator 12 is stacked radially on the first active material layer 200A with the winding axis Z as the center. The separator 12 is also stacked radially on the first inner active material layer 210A. The separator 12 is also stacked radially on the first outer active material layer 220A.

[0083] The first protective portion 300 is electrically insulating, for example, made of ceramic. The first protective portion 300 covers the upper part of the first active material layer 200A. The first protective portion 300 further covers the first current collector 100A between the first tab 150A and the first active material layer 200A.

[0084] The first protective portion 300 includes a first inner protective portion 310 and a first outer protective portion 320. The first inner protective portion 310 covers the upper portion of the first inner active material layer 210A. The first inner protective portion 310 covers a first conductive layer 120 between the first foil portion 151 and the first inner active material layer 210A. The first outer protective portion 320 covers the upper portion of the first outer active material layer 220A. The first outer protective portion 320 covers a second conductive layer 130 between the second foil portion 152 and the first outer active material layer 220A.

[0085] The second protective portion 400 is electrically insulating, for example, made of ceramic. The second protective portion 400 covers the lower part of the first active material layer 200A. The second protective portion 400 also covers the lower side end face of the resin substrate 110.

[0086] The second protective portion 400 includes a second inner protective portion 410 and a second outer protective portion 420. The second inner protective portion 410 covers the lower portion of the first inner active material layer 210A. The second outer protective portion 420 covers the lower portion of the first outer active material layer 220A. The first electrode 11A may also not include the second protective portion 400.

[0087] like Figures 4-6 as well as Figure 9 As shown, the second electrode 11B is stacked on the first active material layer 200A in the aforementioned radial direction, separated by the separator 12. More specifically, the second electrode 11B is stacked on the first inner active material layer 210A, separated by the separator 12, and also on the first outer active material layer 220A, separated by the separator 12.

[0088] The second electrode 11B includes a second current collector 100B and a second active material layer 200B. The second current collector 100B includes a conductive support portion 140 and a plurality of second tabs 150B (see reference). Figure 6 The conductive support portion 140 extends along the orthogonal direction DO (first direction D1). A plurality of second tabs 150B extend from the upper end of the conductive support portion 140. The plurality of second tabs 150B are joined together by ultrasonic welding and are engaged with the second connecting member 40B (see reference). Figure 2 as well as Figure 3 ).

[0089] The plurality of second tabs 150B and the conductive support portion 140 are constituted by an integral component, such as a metal foil. In this embodiment, the plurality of second tabs 150B and the conductive support portion 140 are, for example, made of a metal containing copper. Thus, the second current collector 100B can be suitable for use as a negative current collector. Furthermore, when the first current collector 100A is a negative current collector, the plurality of second tabs 150B and the conductive support portion 140 can be made of a metal containing aluminum.

[0090] The second active material layer 200B is stacked on both sides of the conductive support portion 140 of the second current collector 100B. Furthermore, in this embodiment, the second electrode 11B is the negative electrode. Therefore, the second active material layer 200B is a negative electrode active material layer. Additionally, as... Figure 9 As shown, the edge of the second active material layer 200B on the first direction D1 is located forward of the edge of the first active material layer 200A. Therefore, the edge of the second electrode 11B on the first direction D1 is located forward of the edges of the first conductive layer 120, the second conductive layer 130, and the first active material layer 200A. Furthermore, the second active material layer 200B can also be a positive electrode active material layer.

[0091] Figure 10 This is a development view of the resin substrate according to Embodiment 1. (Refer to...) Figure 10 The detailed structure of the resin substrate 110 in Embodiment 1 will be described.

[0092] like Figure 10 As shown, the resin substrate 110 has a first resin component 110A and a second resin component 110B. The second resin component 110B has higher heat dissipation than the first resin component 110A. For example, the first resin component 110A can be a resin component made of PPS (polyphenylene sulfide), PET (polyethylene terephthalate), etc. As the second resin component 110B, for example, a resin made of PPE (polyphenylene sulfide), polyimide, etc. can be used. PPE has high self-extinguishing properties.

[0093] The resin substrate 110 has an outer end portion 110a and an inner end portion 110b at both ends in the winding direction DR. The outer end portion 110a is located on the outer side in the winding direction when the resin substrate 110 is wound. The inner end portion 110b is located on the inner side in the winding direction in the above-mentioned winding state.

[0094] In the resin substrate 110, the portion located on the inner side of the wound electrode body 10 has a higher heat dissipation performance than the portion located on the outer side of the wound electrode body 10.

[0095] Specifically, when the direction parallel to the winding axis of the winding electrode body 10 is set as the width direction of the resin substrate 110, in the resin substrate 110, as it moves toward the inner side of the winding electrode body 10, the proportion of the second resin member in the width direction becomes larger than the proportion of the first resin member 110A in the width direction. Furthermore, the width direction is parallel to the first direction D1.

[0096] The aforementioned outer end portion 110a and inner end portion 110b each have one end on one side and the other side in the aforementioned width direction, respectively.

[0097] In the unfolded state of the resin substrate 110, the region on one end in the width direction of the region divided into two parts along a diagonal line connecting one end of the outer end 110a to the other end of the inner end 110b is constituted by a second resin member 110B, and the region on the other end in the width direction of the region divided into two parts is constituted by a first resin member 110A. Furthermore, the first resin member 110A and the second resin member 110B are joined together, for example, by welding.

[0098] By constructing the resin substrate 110 in this way, in the wound electrode body 10 where the resin substrate 110 is wound, the proportion of the second resin member 110B disposed on the inner side in the winding direction is greater than the proportion of the first resin member 110A disposed on the inner side in the winding direction. On the other hand, in this wound electrode body 10, the proportion of the first resin member 110A disposed on the outer side in the winding direction is greater than the proportion of the second resin member 110B disposed on the outer side in the winding direction. As a result, the heat dissipation performance of the portion located on the inner side of the wound electrode body 10 is higher than that of the portion located on the outer side of the wound electrode body 10.

[0099] Furthermore, by configuring the second resin member 110B as described above, all of the multiple protruding portions 112 can be constructed from the second resin member 110B, which has high heat dissipation properties. This also improves the heat dissipation from the protruding portions 112.

[0100] Furthermore, by making the second resin component 110B a resin component with high self-extinguishing properties, the wound electrode body 10 can be made to have a self-extinguishing function, and the flame retardancy of the wound electrode body 10 becomes easier.

[0101] Furthermore, in the above example, it is shown that the boundary between the first resin member 110A and the second resin member 110B is straight, and the heat dissipation gradually increases towards the inner side of the wound electrode body 10, but it is not limited to this. The boundary between the first resin member 110A and the second resin member 110B may also be stepped, such that the number of steps increases from the inner end 110b towards the outer end 110a, or the heat dissipation may increase in stages towards the inner side of the wound electrode body 10.

[0102] (Implementation Method 2)

[0103] Figure 11 This is a development view of the resin substrate according to Embodiment 2. (Refer to...) Figure 11 The resin substrate 110X of Embodiment 2 will be described.

[0104] Compared with the resin substrate 110 of Embodiment 1, the resin substrate 110X of Embodiment 2 differs in the arrangement of the first resin member 110A and the second resin member 110B. Other configurations are largely the same. Furthermore, the resin substrate 110X of Embodiment 2 can replace the resin substrate 110 of Embodiment 1 for winding the electrode body 10.

[0105] In this embodiment, the resin substrate 110X is also configured such that the heat dissipation of the portion located inside the wound electrode body 10 is higher than that of the portion located outside the wound electrode body 10.

[0106] In the resin substrate 110X, a first resin member 110A is disposed on one side of the winding direction DR, and a second resin member 110B is disposed on the other side of the winding direction DR. That is, the first resin member 110A is located on the outer end 110a side, and the second resin member 110B is located on the inner end 110b side.

[0107] The proportion of the second resin member 110B, which is arranged along the winding direction DR, is larger than that of the first resin member 110A, which is arranged along the winding direction DR. Specifically, the length of the first resin member 110A along the winding direction DR is shorter than the length of the second resin member 110B along the winding direction DR. The first resin member 110A and the second resin member 110B are joined in a direction parallel to the winding axis.

[0108] By constructing the resin substrate 110X as described above, the heat dissipation of the inner portion of the wound electrode body 10 in the state where the resin substrate 110X is wound can be higher than that of the outer portion of the wound electrode body 10.

[0109] Furthermore, by configuring the second resin member 110B as described above, the proportion of the protruding portions 112 composed of the second resin member 110B with high heat dissipation among the plurality of protruding portions 112 can be increased. As a result, the heat dissipation from the protruding portions 112 can also be improved.

[0110] (Implementation Method 3)

[0111] Figure 12 This is a developed view of the resin substrate according to Embodiment 3. (Refer to...) Figure 12 The resin substrate 110Y of Embodiment 3 will be described.

[0112] Compared with the resin substrate 110X of Embodiment 2, the resin substrate 110Y of Embodiment 3 differs in the joining method (more specifically, the shape of the joining portion) between the first resin member 110A and the second resin member 110B. Other configurations are largely the same. Furthermore, the resin substrate 110Y of Embodiment 3 can replace the resin substrate 110 of Embodiment 1 for winding the electrode body 10.

[0113] In the resin substrate 110Y of Embodiment 3, the first resin member 110A is located on the outer end 110a side, and the second resin member 110B is located on the inner end 110b side. In addition, the proportion of the second resin member 110B arranged along the winding direction DR is larger than that of the first resin member 110A arranged along the winding direction DR.

[0114] In embodiment 3, the first resin member 110A is engaged with the second resin member 110B in a state where it is bitten into along the winding direction DR. As a result, the engagement between the first resin member 110A and the second resin member 110B can be stabilized.

[0115] (Implementation Method 4)

[0116] Figure 13 This is a development view of the resin substrate according to Embodiment 4. (Refer to...) Figure 13 The resin substrate 110Z of Embodiment 4 will be described.

[0117] Compared with the resin substrate 110 of Embodiment 1, the resin substrate 110Z of Embodiment 4 differs in that it is constructed by laminating the first resin member 110A and the second resin member 110B. Furthermore, the resin substrate 110Z of Embodiment 4 can replace the resin substrate 110 of Embodiment 1 when used to wind the electrode body 10.

[0118] In this embodiment, the resin substrate 110Z is also configured such that the heat dissipation of the portion located inside the wound electrode body 10 is higher than that of the portion located outside the wound electrode body 10.

[0119] Specifically, in the resin substrate 110Z, as it moves toward the inner side of the wound electrode body, the second proportion of the resin component 110B in the thickness direction DT becomes larger than the proportion of the first resin component 110A in the thickness direction DT.

[0120] In its unfolded state, the resin substrate 110Z has one end 110c and another end 110d on one side and the other side of the thickness direction DT, respectively. In this unfolded state, the region on one side of the thickness direction DT, which is divided into two parts along a diagonal line connecting the other end 110d of the thickness direction DT located at the outer end 110a to the end 110c of the thickness direction DT located at the inner end 110b, is formed by a first resin member 110A. The region on the other side of the two-part region in the thickness direction DT is formed by a second resin member 110B.

[0121] Even with this configuration, in the wound electrode body 10 where the resin substrate 110Z is wound, the heat dissipation of the portion located on the inner side of the wound electrode body 10 is higher than that of the portion located on the outer side of the wound electrode body 10.

[0122] (Implementation Method 5)

[0123] Figure 14 This is a development view of the resin substrate according to Embodiment 5. (Refer to...) Figure 14The resin substrate 110W of Embodiment 5 will be described.

[0124] Compared with the resin substrate 110 of Embodiment 1, the resin substrate 110W of Embodiment 5 differs in that it controls heat dissipation by adjusting the amount of filler 115 dispersed in a single resin component. Furthermore, the resin substrate 110W of Embodiment 5 can replace the resin substrate 110 of Embodiment 1 when used to wind the electrode body 10.

[0125] like Figure 14 As shown, the amount of filler 115 dispersed is greater on the inner side of the wound electrode body 10 than on the outer side. This results in higher heat dissipation in the portion located on the inner side of the wound electrode body 10 compared to the portion located on the outer side. Regarding the amount of filler 115 dispersed, it can gradually increase towards the inner side of the wound electrode body 10, or it can increase in stages. For example, metal particles such as aluminum can be used as filler 115. Even with the configuration described above, approximately the same effects as in Embodiment 1 can be obtained.

[0126] Embodiments of the present invention have been described, but it should be considered that the embodiments disclosed herein are illustrative rather than restrictive in all inventions. The scope of the invention is defined by the claims and is intended to include all modifications within the scope and equivalent meaning of the claims.

Claims

1. A wound electrode body, which is obtained by winding a first electrode and a second electrode with a polarity different from that of the first electrode into a flat shape with a separator between them. The first electrode includes: Resin substrate; A conductive layer is disposed on the surface of the resin substrate; And a first active material layer, disposed on the main surface of the conductive layer on the side opposite to the side where the resin substrate is located, relative to the conductive layer. The portion of the resin substrate located on the inner side of the wound electrode has higher heat dissipation than the portion located on the outer side of the wound electrode.

2. The wound electrode body according to claim 1, As the coiled electrode moves toward the inside, the heat dissipation of the resin substrate gradually or in stages increases.

3. The wound electrode body according to claim 1, The resin substrate is composed of a first resin component and a second resin component with higher heat dissipation performance than the first resin component. When the direction parallel to the winding axis of the wound electrode body is set as the width direction, in the resin substrate, as it moves toward the inside of the wound electrode body, the proportion of the second resin member in the width direction becomes larger than the proportion of the first resin member in the width direction.

4. The wound electrode body according to claim 1, The resin substrate is formed by laminating a first resin component with a second resin component that has a higher heat dissipation performance than the first resin component. In the resin substrate, as the second resin component moves toward the inside of the wound electrode, the proportion of the second resin component in the thickness direction increases compared to the proportion of the first resin component in the thickness direction.

5. The wound electrode body according to claim 1, The resin substrate includes an inner end located at one end in the winding direction of the wound electrode body and an outer end located at the other end in the winding direction. The resin substrate is formed by joining a first resin component located on the outer end side to a second resin component located on the inner end side, which has a higher heat dissipation capacity than the first resin component. The proportion of the second resin member arranged along the winding direction is greater than the proportion of the first resin member arranged along the winding direction.

6. The wound electrode body according to claim 5, The first resin component is engaged with the second resin component in a manner that bites into it along the winding direction.

7. The wound electrode body according to any one of claims 3 to 6, The second resin component has self-extinguishing properties.

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