Electrode body

Abstract

When an insulating film is used in the electrode body, the heat dissipation of the electrode body is improved. [Solution] The first electrode sheet includes a first portion L1 located on the outermost periphery and winding once around the winding axis, a second portion L2 located inside the first portion L1 and winding once around the winding axis, and a third portion L3 located inside the second portion L2 and winding once around the winding axis. The plurality of holes P include a first hole P1 formed in the first portion L1, a second hole P2 formed in the second portion L2, and a third hole P3 formed in the third portion L3. Of the second portion L2, if the portion facing the first hole P1 in a direction perpendicular to the surface of the first portion L1 is designated as the first opposing portion, then the second hole P2 is formed at a position away from the first opposing portion. Of the third portion L3, if the portion facing the second hole P2 in a direction perpendicular to the surface of the second portion L2 is designated as the second opposing portion, then the third hole P3 is formed at a position away from the second opposing portion.

Description

Technical Field

[0001] The present disclosure relates to an electrode body.

Background Art

[0002] JP-A-2019-96592 discloses an electrode body (electrode member) including an insulating substrate (insulating film) and conductive layers (conductive films) provided on two surfaces of the insulating substrate facing each other in the thickness direction. JP-A-2019-96592 discloses that through holes (hole portions) penetrating in the thickness direction are formed in the insulating substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when an insulating film is used for the electrode body, since the thermal conductivity of the insulating film is low, the heat dissipation property of the electrode body deteriorates. When an insulating film is used for the electrode body, it is required to improve the heat dissipation property of the electrode body.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide an electrode body in which the heat dissipation property of the electrode body is improved when an insulating film is used for the electrode body.

Means for Solving the Problems

[0006] (1) An electrode body according to a certain aspect of the present disclosure is an electrode body in which a laminated sheet including a first electrode sheet, a separator, and a second electrode sheet is wound around a winding axis. The first electrode sheet includes a current collector layer including an insulating film and a conductive film provided on the surface of the insulating film, and an active material layer provided on the main surface of the conductive film, which is located on the side opposite to the side where the insulating film is located relative to the conductive film. A plurality of holes penetrating the current collector layer are formed in the region of the current collector layer in which the active material layer is laminated. A high thermal conductivity portion is formed in each of the plurality of holes. The high thermal conductivity portion is formed of a material having a higher thermal conductivity than the thermal conductivity of the insulating film. In the wound state in which the first electrode sheet is wound around a winding axis, it includes a first portion located on the outermost periphery and making one turn around the winding axis, a second portion located inside the first portion and making one turn around the winding axis, and a third portion located inside the second portion and making one turn around the winding axis. The multiple holes include a first hole formed in the first portion, a second hole formed in the second portion, and a third hole formed in the third portion. If the portion of the second portion facing the first hole in a direction perpendicular to the surface of the first portion is designated as the first opposing portion, then the second hole is formed at a position away from the first opposing portion. If the portion of the third portion facing the second hole in a direction perpendicular to the surface of the second portion is designated as the second opposing portion, then the third hole is formed at a position away from the second opposing portion.

[0007] (2) In the electrode body described in (1) above, the high thermal conductivity portion is formed by at least one of a conductive film covering the inner circumferential surface that defines each of the plurality of holes, and an active material layer covering the inner circumferential surface.

[0008] (3) In the electrode body described in (1) above, each of the multiple holes is formed such that the length in the direction in which the winding axis extends is longer than the length in the direction perpendicular to the winding axis.

[0009] (4) The electrode body described in (1) above includes a flat region and a curved region in the wound state. The density of the multiple holes is higher in the curved region than in the flat region.

[0010] (5) The electrode body described in (1) above includes a flat region and a curved region in the wound state. The density of the multiple holes is higher in the flat region than in the curved region.

[0011] (6) The electrode body described in (1) above includes an end located on one side in the direction in which the winding axis extends. The current collector layer includes an end edge located at the end. The current collector layer includes a protruding piece formed on the end edge and projecting in the direction in which the winding axis extends. The protruding piece includes a root portion located on the end edge side and a tip portion extending from the root portion in the direction in which the winding axis extends. The protruding piece has two or more holes formed through it. The density of the two or more holes is lower at the root portion than at the tip portion.

[0012] (7) The electrode body described in (1) above includes an end located on one side in the direction in which the winding axis extends. The current collector layer includes an end edge located at the end. The current collector layer includes a protruding piece formed on the end edge and projecting in the direction in which the winding axis extends. The protruding piece includes a root portion located on the end edge side and a tip portion extending from the root portion in the direction in which the winding axis extends. The protruding piece has two or more holes that penetrate it. The density of the two or more holes is lower at the tip portion than at the root portion. [Effects of the Invention]

[0013] According to this disclosure, when an insulating film is used in the electrode body, the heat dissipation of the electrode body can be improved. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view showing a power storage cell including an electrode body according to this embodiment. [Figure 2] Figure 1 is a perspective view showing the electrode body 10. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 2. [Figure 4] This is a perspective view showing a magnified portion of the first electrode sheet 1. [Figure 5]It is a plan view showing the deployed current collector layer 110. [Figure 6] It is a plan view showing an enlarged view of the protruding piece portion T1 shown in FIG. 5. [Figure 7] It is a plan view showing an enlarged view of the protruding piece portion of the electrode body in Modification 1. [Figure 8] It is a plan view showing the deployed current collector layer of the first electrode sheet of the electrode body in Modification 2.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments and modifications of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0016] [Embodiment] FIG. 1 is a perspective view showing a storage battery cell including an electrode body according to the present embodiment. The storage battery cell 100 is a so-called rectangular battery. The storage battery cell 100 is a secondary battery configured to be capable of charging and discharging. The storage battery cell 100 may be a secondary battery such as a lithium-ion battery or a nickel-hydrogen battery. The storage battery cell 100 can be used, for example, as a cell included in a power storage module mounted on an electric vehicle.

[0017] The storage battery cell 100 includes an electrode body 10, a case 50, a first external terminal 61, a second external terminal 62, a first terminal support portion 71, and a second terminal support portion 72. In FIG. 1, the electrode body 10 is schematically shown.

[0018] The case 50 has conductivity. The conductive portion of the case 50 is made of a metal such as aluminum. The case 50 houses the electrode body 10. The case 50 also houses an electrolytic solution (not shown).

[0019] Case 50 includes a case body 51 and a lid 52. The case body 51 includes a bottom wall 510 and a peripheral wall 511 rising from the bottom wall 510. The bottom wall 510 and the lid 52 are spaced apart in a first direction. The first direction corresponds to the vertical direction. The first, second, and third directions shown in Figure 1 are orthogonal to each other. Note that the first, second, and third directions only need to intersect each other, and do not need to be orthogonal to each other.

[0020] The lid 52 includes a lid body 520 and an insulating cover 521. The lid body 520 is joined to the peripheral wall 511 by welding or the like so as to close the opening in the peripheral wall 511.

[0021] The first external terminal 61 and the second external terminal 62 are spaced apart in the third direction. The first external terminal 61 and the second external terminal 62 are provided to be exposed to the outside in the energy storage cell 100. The first external terminal 61 is the positive terminal, and the second external terminal 62 is the negative terminal.

[0022] The first terminal support portion 71 is locked to the lid body 520. The first terminal support portion 71 supports the first external terminal 61 from the outer circumference of the first external terminal 61. The second terminal support portion 72 is locked to the lid body 520. The second terminal support portion 72 supports the second external terminal 62 from the outer circumference of the second external terminal 62.

[0023] Figure 2 is a perspective view showing the electrode body 10 shown in Figure 1. The electrode body 10 is a wound electrode body in which a laminated sheet S is wound around a winding axis M. The direction D1 in which the winding axis M extends is substantially parallel to the first direction shown in Figure 1. The laminated sheet S includes a plurality of portions L that make one turn around the winding axis M, a plurality of protruding pieces T1, and a plurality of protruding pieces T2. A first current collector tab (not shown) is joined to the plurality of protruding pieces T1, and a second current collector tab (not shown) is joined to the plurality of protruding pieces T2. The first current collector tab is electrically connected to a first external terminal 61 (see Figure 1) by a first connecting member (not shown). The second current collector tab is electrically connected to a second external terminal 62 (see Figure 1) by a second connecting member (not shown).

[0024] Figure 3 is a cross-sectional view taken along line III-III in Figure 2. In Figure 3, the protruding portion T1 is omitted. The laminated sheet S includes a first electrode sheet 1, a separator 3, and a second electrode sheet 2. The first electrode sheet 1, the separator 3, and the second electrode sheet 2 are laminated in the lamination direction D2 and wound around the winding axis M (see Figure 2). The electrode body 10 may also be a laminated electrode body in which the first electrode sheet 1, the separator 3, and the second electrode sheet 2 are laminated in the lamination direction D2.

[0025] The first electrode sheet 1 is the positive electrode. The first electrode sheet 1 includes a current collector layer 110 and two active material layers 120. The current collector layer 110 includes an insulating film 11 and two conductive films 12.

[0026] The insulating film 11 is made of an electrically insulating resin composition. For example, the insulating film 11 is made of a resin composition containing a polyester resin. The polyester resin is preferably polyethylene terephthalate, for example. This makes it possible to increase the rigidity of the current collector layer 110 while maintaining the electrical insulating properties of the insulating film 11. Consequently, the insulating film 11 can be made relatively thin. The insulating film 11 includes surfaces 111a and 111b that are spaced apart in the lamination direction D2. Each of surfaces 111a and 111b is a surface along the winding direction D3. Surface 111b is located closer to the winding axis M than surface 111a.

[0027] Each of the two conductive films 12 consists of a metal layer. Each conductive film 12 consists of a metal containing aluminum. This allows the current collector layer 110 to be suitably used as a positive electrode current collector. The two conductive films 12 include conductive film 12a and conductive film 12b. Conductive film 12a is provided on the surface 111a of the insulating film 11. Conductive film 12b is provided on the surface 111b of the insulating film 11. Conductive films 12a and 12b are deposited on the insulating film 11.

[0028] The current collector layer 110 includes a region R1 in which the active material layer 120 is laminated and a region R2 in which the active material layer 120 is not laminated.

[0029] The two active material layers 120 include an active material layer 120a and an active material layer 120b. The active material layer 120a is provided on the main surface 112a of the conductive film 12a, on the side opposite to the side where the insulating film 11 is located relative to the conductive film 12a. The active material layer 120b is provided on the main surface 112b of the conductive film 12b, on the side opposite to the side where the insulating film 11 is located relative to the conductive film 12b. The main surfaces 112a and 112b correspond to two main surfaces of the current collector layer 110 that are spaced apart in the lamination direction D2. The main surfaces 112a and 112b are surfaces along the winding direction D3. The active material layer 120a is coated on the conductive film 12a, and the active material layer 120b is coated on the conductive film 12b.

[0030] The second electrode sheet 2 is the negative electrode. The second electrode sheet 2 includes a current collector layer 210 and two active material layers 220. The current collector layer 210 includes a conductive film 22. The conductive film 22 consists of a metal layer. The conductive film 22 consists of a metal containing copper. Thus, the current collector layer 210 can be suitably used as a negative electrode current collector. The conductive film 22 includes main surfaces 122a and 122b that are spaced apart in the lamination direction D2. The main surfaces 122a and 122b correspond to two main surfaces of the current collector layer 210 that are spaced apart in the lamination direction D2. The main surfaces 122a and 122b are surfaces along the winding direction D3.

[0031] The two active material layers 220 include an active material layer 220a and an active material layer 220b. Active material layer 220a is provided on the main surface 122a. Active material layer 220b is provided on the main surface 122b. Active material layers 220a and 220b are coated onto the conductive film 22.

[0032] The separator 3 is provided between the first electrode sheet 1 and the second electrode sheet 2. The separator 3 separates the first electrode sheet 1 and the second electrode sheet 2 while allowing ions to move between them. The ions are, for example, lithium ions. The separator 3 has electrical insulating properties.

[0033] In the region R1 of the current collector layer 110 where the active material layer 120 is laminated, a plurality of holes P are formed that penetrate the current collector layer 110 in the lamination direction D2. A high thermal conductivity portion Q is formed in each of the plurality of holes P. The high thermal conductivity portion Q is formed of a material having a higher thermal conductivity than the thermal conductivity of the insulating film 11. In this embodiment, the high thermal conductivity portion Q is formed by a conductive film 12 that covers the inner circumferential surface defining each of the plurality of holes P, and the active material layer 120 filled in the holes P.

[0034] Furthermore, the high thermal conductivity portion Q is formed by a conductive film 12 covering the inner circumferential surface defining each of the multiple holes P, and the holes P do not necessarily have to be filled with an active material layer 120. Alternatively, the high thermal conductivity portion Q may be formed by an active material layer 120 covering the inner circumferential surface defining each of the multiple holes P, and an active material layer 120 filling the holes P. Alternatively, the high thermal conductivity portion Q is formed by an active material layer 120 covering the inner circumferential surface defining each of the multiple holes P, and the holes P do not necessarily have to be filled with an active material layer 120. Alternatively, the high thermal conductivity portion Q may be formed by a conductive film 12 covering the inner circumferential surface defining each of the multiple holes P, and an active material layer 120 covering said inner circumferential surface.

[0035] The first electrode sheet 1, in a wound state where it is wound around the winding axis M, includes a first portion L1 located on the outermost periphery and making one turn around the winding axis M, a second portion L2 located inside the first portion L1 and making one turn around the winding axis M, and a third portion L3 located inside the second portion L2 and making one turn around the winding axis M. The plurality of holes P include a first hole P1 formed in the first portion L1, a second hole P2 formed in the second portion L2, and a third hole P3 formed in the third portion L3.

[0036] Figure 4 is a magnified perspective view of a portion of the first electrode sheet 1. For clarity, the active material layer 120 is omitted in Figure 4. Of the second portion L2, if the portion facing the first hole portion P1 in a direction perpendicular to the surface K1 of the first portion L1 is designated as the first opposing portion J1, then the second hole portion P2 is formed at a position away from the first opposing portion J1. Surface K1 is the surface of the first portion L1 along the winding direction D3. The direction perpendicular to surface K1 corresponds to the lamination direction D2.

[0037] In the third portion L3, if the portion facing the second hole P2 in a direction perpendicular to the surface K2 of the second portion L2 is defined as the second opposing portion J2, then the third hole P3 is formed at a position away from the second opposing portion J2. Surface K2 is the surface of the second portion L2 along the winding direction D3. The direction perpendicular to surface K2 corresponds to the lamination direction D2.

[0038] Figure 5 is a plan view showing the unfolded current collector layer 110. Each of the multiple holes P is formed such that the length in the direction D1 in which the winding axis M extends is longer than the length in the direction perpendicular to the winding axis M (see Figure 2). Alternatively, each hole P may be formed such that the length in the direction perpendicular to the winding axis M is equal to the length in the direction D1 in which the winding axis M extends.

[0039] The electrode body 10 (specifically, the current collector layer 110) includes a flat region H and a curved region W in its wound state. The density of the multiple holes P is higher in the curved region W than in the flat region H. However, the density of the multiple holes P may be the same in the curved region W and the flat region H.

[0040] Referring again to Figure 2, the electrode body 10 includes ends E1 and E2, which are spaced apart in the direction D1 in which the winding axis M extends. End E1 is the end of the electrode body 10 located on one side in the direction D1 in which the winding axis M extends. Referring again to Figure 5, the current collector layer 110 includes an end F1 located at end E1 (see Figure 2). The current collector layer 110 includes a protruding piece T1 formed on the end F1 and projecting in the direction D1 in which the winding axis M extends. The protruding piece T1 is formed in a region R2 in which the active material layer 120 is not laminated.

[0041] Figure 6 is a plan view showing an enlarged view of the protruding portion T1 shown in Figure 5. The protruding portion T1 includes a root portion T11 located on the end side F1 and a tip portion T12 extending from the root portion T11 in the direction D1 in which the winding axis M extends. A first current collector tab (not shown) is joined to the tip portion T12. Two or more holes U are formed in the protruding portion T1. Each of the two or more holes U penetrates the protruding portion T1 of the current collector layer 110 in the stacking direction D2. Each hole U is formed such that the length in the direction D1 in which the winding axis M extends is longer than the length in the direction perpendicular to the winding axis M (see Figure 2). Alternatively, each hole U may be formed such that the length in the direction perpendicular to the winding axis M is equal to the length in the direction D1 in which the winding axis M extends. Furthermore, each hole U may be formed such that the length in the direction perpendicular to the winding axis M is longer than the length in the direction D1 in which the winding axis M extends.

[0042] A conductive portion V is formed in each of the two or more holes U. The conductive portion V is formed by a conductive film 12 (see Figure 3) that covers the inner circumferential surface defining the hole U. The density of the two or more holes U is lower at the base portion T11 than at the tip portion T12.

[0043] As described above, in this embodiment, the current collector layer 110 has a plurality of holes P that penetrate through it. A highly thermally conductive portion Q is formed in each hole P. Generally, when an insulating film is used for the electrode body, the thermal conductivity of the insulating film is low, so the heat dissipation performance of the current collector layer including the insulating film and conductive film is reduced. In contrast, in this embodiment, the current collector layer 110 has a plurality of holes P in which highly thermally conductive portions Q are formed. This makes it possible to improve the heat dissipation performance of the electrode body 10.

[0044] Furthermore, generally speaking, when several holes are arranged in a row, the heat dissipation of the area of ​​the electrode body where the holes are arranged in a row will be higher than that of other areas of the electrode body. As a result, temperature unevenness occurs on the surface of the electrode body (the surface along the winding direction of the electrode sheet). When temperature unevenness occurs on the surface of the electrode body, heat transfer occurs between high-temperature and low-temperature areas on the surface of the electrode body, which may reduce the heat dissipation of the electrode body.

[0045] In contrast, in this embodiment, as explained with reference to Figure 4, the second hole P2 is formed at a position away from the first opposing portion J1, and the third hole P3 is formed at a position away from the second opposing portion J2. As a result, in this embodiment, the holes P are not aligned in a line in the first portion L1, which is located on the outermost periphery of the first electrode sheet 1, the second portion L2, which is located inside the first portion L1, and the third portion L3, which is located inside the second portion L2. This suppresses the occurrence of temperature unevenness on the surface of the electrode body 10. Therefore, according to this embodiment, heat can be efficiently released from the surface of the electrode body 10. Consequently, according to this embodiment, the heat dissipation performance of the electrode body can be improved when an insulating film is used for the electrode body.

[0046] According to this embodiment, the high thermal conductivity portion Q is formed by at least one of a conductive film 12 covering the inner circumferential surface defining each of the multiple holes P, and an active material layer 120 covering the inner circumferential surface. When the conductive film 12 is deposited on the insulating film 11, the conductive film 12 easily adheres to the inner circumferential surface defining the holes P. Also, when the active material layer 120 is coated onto the conductive film 12, the active material layer 120 easily adheres to the inner circumferential surface defining the holes P. Therefore, according to this embodiment, the high thermal conductivity portion Q can be easily formed in the holes P. Furthermore, when the high thermal conductivity portion Q is formed by a conductive film 12 covering the inner circumferential surface defining each of the multiple holes P, the conductivity of the electrode body 10 can be improved because the inner circumferential surface is covered by the conductive film 12.

[0047] According to this embodiment, each of the multiple holes P is formed such that the length in the direction D1 in which the winding axis M extends is longer than the length in the direction perpendicular to the winding axis M. Generally, in an electrode body, current is collected in the direction in which the winding axis extends. Therefore, according to this embodiment, it is possible to suppress an increase in current collection resistance.

[0048] According to this embodiment, the density of the multiple holes P is higher in the curved region W than in the flat region H. This makes it easier to bend the electrode body 10 in the curved region W.

[0049] In this embodiment, the protruding piece T1 has two or more holes U formed therein. This improves the heat dissipation of the protruding piece T1. In addition, in this embodiment, the density of the two or more holes U is lower at the base T11 than at the tip T12. The current collection path is concentrated at the base T11. Therefore, by lowering the density of the holes U at the base T11, it is possible to suppress a decrease in current collection efficiency. Furthermore, as described above, the first current collection tab is joined to the tip T12. Since a conductive part V is formed in each hole U, the electrical resistance at the joint between the tip T12 and the first current collection tab can be reduced.

[0050] [Example 1] Figure 7 is a plan view showing an enlarged view of the protruding portion of the electrode body in Modified Example 1. The difference between the electrode body in Modified Example 1 and the electrode body 10 in the above embodiment is the protruding portion of the current collector layer 110. In other respects, the electrode body in Modified Example 1 is the same as the electrode body 10 in the above embodiment.

[0051] In Modified Example 1, the electrode body includes a protruding piece T1A instead of a protruding piece T1 (see Figure 6) as a protruding piece of the current collector layer 110. Specifically, in Modified Example 1, the current collector layer 110 includes a protruding piece T1A formed on the end edge F1 and protruding in the direction D1 in which the winding axis M extends. The protruding piece T1A is formed in a region R2 (see Figure 5) where the active material layer 120 is not laminated. The protruding piece T1A includes a root portion T11A located on the end edge F1 side and a tip portion T12A extending from the root portion T11A in the direction D1 in which the winding axis M extends. A first current collector tab (not shown) is joined to the tip portion T12A. Two or more holes U are formed in the protruding piece T1A. Each of the two or more holes U penetrates the protruding piece T1A of the current collector layer 110 in the lamination direction D2. A conductive portion V is formed in each of the two or more holes U. The conductive portion V is formed by a conductive film 12 (see Figure 3) that covers the inner circumferential surface defining the hole U. The density of the two or more holes U is lower at the tip portion T12A than at the base portion T11A. In other respects, the protruding piece T1A in Modification 1 is the same as the protruding piece T1 in the above embodiment.

[0052] As described above, in Modification 1, the protruding piece T1A has two or more holes U formed therein. Therefore, the heat dissipation of the protruding piece T1A is improved. Also, in the electrode body of Modification 1, the density of two or more holes U is lower at the tip T12A than at the base T11A. As mentioned above, the first current collector tab is joined to the tip T12A. Therefore, by lowering the density of holes U at the tip T12A, the electrical resistance at the joint between the tip T12A and the first current collector tab can be reduced. In addition, the current collection path is concentrated at the base T11A. Since a conductive part V is formed in each hole U, a decrease in current collection efficiency can be suppressed.

[0053] [Differentiation 2] Figure 8 is a plan view showing the unfolded current-collecting layer of the first electrode sheet of the electrode body in Modification 2. The difference between the electrode body in Modification 2 and the electrode body 10 in the above embodiment is the current-collecting layer of the first electrode sheet. In other respects, the electrode body in Modification 2 is the same as the electrode body 10 in the above embodiment.

[0054] Specifically, in Modified Example 2, the electrode body includes a current collector layer 110B instead of the current collector layer 110 (see Figure 5) as the current collector layer of the first electrode sheet 1 (see Figure 3). In the region R1 of the current collector layer 110B where the active material layer 120 (see Figure 3) is laminated, a plurality of holes P are formed that penetrate the current collector layer 110B in the lamination direction D2. In Modified Example 2, the electrode body (specifically, the current collector layer 110B) includes a flat region H and a curved region W when wound. The difference between the current collector layer 110B and the current collector layer 110 lies in the density of the plurality of holes P in the curved region W and the density in the flat region H. In Modified Example 2, the density of the plurality of holes P is higher in the flat region H than in the curved region W. In other respects, the current collector layer 110B in Modified Example 2 is the same as the current collector layer 110 in the above embodiment.

[0055] Thus, according to Modification 2, the density of multiple holes P is higher in the flat region H than in the curved region W. Generally, the flat region H is often closer to case 50 (see Figure 1) than in the curved region W. Therefore, the heat dissipation of the flat region H is often lower than that of the curved region W. In contrast, according to Modification 2, the density of multiple holes P is higher in the flat region H than in the curved region W. Therefore, according to Modification 2, the heat dissipation of the flat region H can be improved.

[0056] The embodiments and variations disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications are intended to be within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0057] 1 First electrode sheet, 2 Second electrode sheet, 3 Separator, 10 Electrode body, 11 Insulating film, 12, 12a, 12b, 22 Conductive film, 50 Case, 51 Case body, 52 Lid, 61 First external terminal, 62 Second external terminal, 71 First terminal support, 72 Second terminal support, 100 Energy storage cell, 110, 210, 110B Current collector layer, 111a, 111b, K1, K2 Surface, 112a, 112b, 122a, 122b Main surface, 120, 120a, 120b, 220, 220a, 220b Active material layer, 510 Bottom wall, 511 Peripheral wall, 520 Lid body, 521 Insulating cover, D1 Direction, D2 Lamination direction, D3 Winding direction, E1, E2 End, F1 Edge, H flat area, J1 1st opposing part, J2 2nd opposing part, L part, L1 1st part, L2 2nd part, L3 3rd part, M winding axis, P,U hole, P1 1st hole, P2 2nd hole, P3 3rd hole, Q high thermal conductivity part, R1,R2 area, S laminated sheet, T1,T1A,T2 Projecting piece part, T11, T11A root part, T12, T12A tip part, V conductive part, W curved area.

Claims

1. An electrode body in which a laminated sheet including a first electrode sheet, a separator, and a second electrode sheet is wound around a winding axis, The first electrode sheet is A current collector layer including an insulating film and a conductive film provided on the surface of the insulating film, The conductive film includes an active material layer provided on the main surface of the conductive film that is located on the side opposite to the side where the insulating film is located, In the region of the current collector layer in which the active material layer is laminated, a plurality of holes penetrating the current collector layer are formed. Each of the aforementioned multiple holes has a high heat conductivity portion formed therein. The high thermal conductivity portion is formed of a material having a higher thermal conductivity than the thermal conductivity of the insulating film. The first electrode sheet, in a wound state where it is wound around the winding axis, includes a first portion located on the outermost periphery and making one turn around the winding axis, a second portion located inside the first portion and making one turn around the winding axis, and a third portion located inside the second portion and making one turn around the winding axis. The plurality of holes include a first hole formed in the first portion, a second hole formed in the second portion, and a third hole formed in the third portion. If the portion of the second part that faces the first hole in a direction perpendicular to the surface of the first part is called the first opposing portion, then the second hole is formed at a position away from the first opposing portion. Of the third portion, if the portion facing the second hole in a direction perpendicular to the surface of the second portion is defined as the second opposing portion, then the third hole is an electrode body formed at a position away from the second opposing portion.

2. The electrode body according to claim 1, wherein the high thermal conductivity portion is formed by at least one of the conductive film covering the inner circumferential surface defining each of the plurality of holes and the active material layer covering the inner circumferential surface.

3. The electrode body according to claim 1, wherein each of the plurality of holes is formed such that the length in the direction in which the winding axis extends is longer than the length in the direction perpendicular to the winding axis.

4. The electrode body, in the wound state, includes a flat region and a curved region. The electrode body according to claim 1, wherein the density of the plurality of holes is higher in the curved region than in the flat region.

5. The electrode body, in the wound state, includes a flat region and a curved region. The electrode body according to claim 1, wherein the density of the plurality of holes is higher in the flat region than in the curved region.

6. The electrode body includes an end located on one side in the direction in which the winding axis extends, The current collector layer includes the end edge located at the end, The current collector layer includes a protruding piece formed on the end edge and projecting in the direction in which the winding axis extends, The protruding portion includes a root portion located on the end side and a tip portion extending from the root portion in the direction in which the winding axis extends. The protruding piece has two or more holes that penetrate it. The electrode body according to claim 1, wherein the density of the two or more holes is lower at the base than at the tip.

7. The electrode body includes an end located on one side in the direction in which the winding axis extends, The current collector layer includes the end edge located at the end, The current collector layer includes a protruding piece formed on the end edge and projecting in the direction in which the winding axis extends, The protruding portion includes a root portion located on the end side and a tip portion extending from the root portion in the direction in which the winding axis extends, The protruding piece has two or more holes that penetrate it. The electrode body according to claim 1, wherein the density of the two or more holes is lower at the tip than at the base.

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