Current collector and battery

Abstract

This suppresses localized heat generation in the current collector. [Solution] The current collector 100A comprises a support layer 110, a conductive layer 120, and a tab portion 140. The support layer 110 is made of an electrically insulating resin composition. The conductive layer 120 is laminated on the support layer 110. The tab portion 140 is made of a film-like material. The tab portion 140 includes a tab body portion 141 and a heat dissipation portion 142. The tab body portion 141 is connected to the conductive layer 120. The tab body portion 141 is configured to be connectable to other conductive members so as to be electrically connected to them. The heat dissipation portion 142 is bent multiple times.

Description

Technical Field

[0001] The present disclosure relates to a current collector and a battery.

Background Art

[0002] Japanese Patent Publication No. 2024-510696 discloses a conventional electrode plate. The electrode plate includes a current collector, an active material layer, and an electrical connection member. The current collector includes a support layer and a conductive layer. The support layer is made of an insulating material. The conductive layer is provided on one surface of the support layer. The electrical connection member and the current collector are welded and connected at the edge of the current collector. This welded connection region is called an intermediate welding region.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional current collector, the support layer is an insulating material. Therefore, the electrical resistance of the current collector is relatively high. Then, the intermediate welding region is likely to generate heat when energized.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a current collector capable of suppressing local heat generation and a battery including the same.

Means for Solving the Problems

[0006] A current collector according to a certain aspect of the present disclosure comprises a support layer, a conductive layer, and a tab portion. The support layer is made of an electrically insulating resin composition. The conductive layer is laminated on the support layer. The tab portion is made of a film-like material. The tab portion includes a tab body and a heat dissipation portion. The tab body is connected to the conductive layer. The tab body is configured to be joinable to other conductive members so as to be electrically connected to them. The heat dissipation portion is bent multiple times.

[0007] A battery according to a certain aspect of this disclosure comprises an electrode body and an external terminal. The electrode body includes a first electrode, a second electrode, and a separator. The first electrode includes a current collector and an active material layer. The current collector includes a support layer, a conductive layer, and a tab portion. The support layer is made of an electrically insulating resin composition. The conductive layer is laminated to the support layer. The tab portion is made of a film-like material. The tab portion includes a tab body and a heat dissipation portion. The tab body is connected to the conductive layer. The tab body is configured to be connectable to other conductive members so as to be electrically connected to other conductive members. The heat dissipation portion is bent multiple times. The active material layer is laminated to the conductive layer. The separator is laminated to the active material layer. The second electrode is laminated to the active material layer via the separator. The external terminal is electrically connected to the tab body. [Effects of the Invention]

[0008] According to this disclosure, localized heat generation in the current collector can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing a battery according to Embodiment 1. [Figure 2] This is a cross-sectional view of the electrode body in Figure 1, taken in the direction of the arrow line II-II. [Figure 3] This is an exploded view of the first electrode in Embodiment 1. [Figure 4] This is a view from one direction of the tab portion of the deployed first electrode according to Embodiment 1. [Figure 5]This is a partial cross-sectional view of the first electrode in Figure 3, as seen in the direction of the VV arrow. [Figure 6] This is a partial cross-sectional view of the first electrode in Figure 3, as seen in the direction of the arrow along the line VI-VI. [Figure 7] This is an exploded view of the first electrode in Embodiment 2. [Figure 8] This is a partial cross-sectional view of the first electrode in Figure 7, taken in the direction of the VIII-VIII arrow. [Modes for carrying out the invention]

[0010] Hereinafter, current collectors and batteries according to each embodiment of this disclosure will be described with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated.

[0011] (Embodiment 1) Figure 1 is a cross-sectional view showing a battery according to Embodiment 1. The battery 1 shown in Figure 1 is a so-called prismatic battery. Battery 1 may be a rechargeable secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. Battery 1 can be used, for example, as a cell included in an energy storage module mounted on an electric vehicle.

[0012] As shown in Figure 1, the battery 1 according to Embodiment 1 of the present disclosure comprises an electrode body 10, a case 20, a first external terminal 30A, a second external terminal 30B, a first connecting member 40A, and a second connecting member 40B. First, the components of the battery 1 other than the electrode body 10 will be described.

[0013] Case 20 is conductive. The conductive portion of Case 20 is made of a metal such as aluminum. Case 20 houses the electrode body 10. Case 20 also houses an electrolyte solution, which is not shown in the diagram.

[0014] Case 20 includes a case body 21 and a lid 22. The case body 21 includes a bottom wall 21a and a peripheral wall 21b that rises from the bottom wall 21a.

[0015] The lid 22 is joined to the peripheral wall 21b by welding or the like so as to close the opening of the peripheral wall 21b. The lid 22 has a first connection hole 22a and a second connection hole 22b formed therein.

[0016] The first external terminal 30A and the second external terminal 30B are provided so as to be exposed to the outside in the battery 1. The first connecting member 40A and the second connecting member 40B have conductivity. At least a part of the first connecting member 40A and the second connecting member 40B is disposed inside the case 20.

[0017] The first external terminal 30A or the first connecting member 40A is inserted into the first connection hole 22a. The first external terminal 30A is electrically connected to the first connecting member 40A. Specifically, the first external terminal 30A and the first connecting member 40A are joined to each other. The first connecting member 40A is joined to the electrode body 10. Thereby, the first external terminal 30A is electrically connected to the electrode body 10.

[0018] The second external terminal 30B or the second connecting member 40B is inserted into the second connection hole 22b. The second external terminal 30B is electrically connected to the second connecting member 40B. Specifically, the second external terminal 30B and the second connecting member 40B are joined to each other. The second connecting member 40B is joined to the electrode body 10. Thereby, the second external terminal 30B is electrically connected to the electrode body 10.

[0019] In this embodiment, the first external terminal 30A is a positive electrode terminal and the second external terminal 30B is a negative electrode terminal. The first external terminal 30A and the second external terminal 30B are arranged side by side in the second direction D2. The second direction D2 is a direction orthogonal to the first direction D1.

[0020] Next, the electrode body 10 will be described. The battery 1 according to this embodiment includes a plurality of electrode bodies 10. The battery 1 typically includes two electrode bodies 10. These electrode bodies 10 are arranged side by side in the third direction D3. The third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2.

[0021] In the following, one of the multiple electrode bodies 10 will be described. Note that each of the multiple electrode bodies 10 may have the configuration shown below.

[0022] Figure 2 is a cross-sectional view of the electrode body of Figure 1, viewed in the direction of the arrow II-II. As shown in Figures 1 and 2, the electrode body 10 includes a first electrode 11A, a second electrode 11B, and a separator 12. The electrode body 10 is wound such that the first electrode 11A, the second electrode 11B, and the separator 12 surround a winding axis Z. Thus, in this embodiment, the electrode body 10 is a so-called wound electrode body. However, the electrode body 10 may also be a laminated electrode body in which the first electrode 11A, the second electrode 11B, and the separator 12 are stacked in one direction (for example, a third direction D3). In Figure 2, the separator 12 is schematically shown by a dashed line.

[0023] The first electrode 11A and the second electrode 11B have a sheet-like outer shape. The electrode body 10 is composed of a group of electrode plates in which the first electrode 11A and the second electrode 11B are wound around one or more separators 12. In this embodiment, the first electrode 11A is the positive electrode and the second electrode 11B is the negative electrode. However, the first electrode 11A may be the negative electrode and the second electrode 11B may be the positive electrode.

[0024] The separator 12 is provided between the first electrode 11A and the second electrode 11B. The separator 12 separates the first electrode 11A and the second electrode 11B while allowing ions to move between them. The ions are, for example, lithium ions. The separator 12 has electrical insulating properties.

[0025] Figure 3 is an unfolded view of the first electrode in Embodiment 1. That is, Figure 3 shows the state of the first electrode 11A before it is wound. Figure 4 is a view of the tab portion of the unfolded first electrode according to Embodiment 1, seen from one direction. Figure 5 is a partial cross-sectional view of the first electrode in Figure 3, viewed in the direction of the VV arrow. Figure 6 is a partial cross-sectional view of the first electrode in Figure 3, viewed in the direction of the VI-VI arrow.

[0026] As shown in Figures 2 to 6, the first electrode 11A includes a first current collector 100A, a first active material layer 200A, a first protective section 400, and a second protective section 500.

[0027] The first current collector 100A includes a support layer 110, a first conductive layer 120, a second conductive layer 130, and a plurality of tab portions 140.

[0028] The support layer 110 is made of an electrically insulating resin composition. Therefore, the first current collector 100A is a composite current collector made of a conductive material and an electrically insulating material. As a result, the first current collector 100A is lighter and the overall safety of the battery 1 is improved compared to when the first current collector 100A is made entirely of metal.

[0029] The support layer 110 is made of a resin composition containing, for example, a polyamide resin, a polyester resin, or a polyolefin resin. To increase rigidity, it is preferable that the support layer 110 is made of a resin composition containing a polyester resin. It is even more preferable that the support layer 110 is substantially made of a polyester resin. The polyester resin may be, for example, polyethylene terephthalate. This makes it possible to increase the rigidity of the first current collector 100A while maintaining the electrical insulation properties of the support layer 110. Consequently, the support layer 110 can be made relatively thin.

[0030] The thickness direction DT of the support layer 110 is approximately perpendicular to the first direction D1. That is, the support layer 110 extends in a direction approximately perpendicular to the first direction D1.

[0031] The thickness of the support layer 110 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less, in order to reduce the overall thickness of the electrode body 10. The thickness of the support layer 110 is not particularly limited as long as it has the desired rigidity. The thickness of the support layer 110 may be, for example, 2 μm or more.

[0032] The first conductive layer 120 is laminated on the support layer 110. The first conductive layer 120 is provided on one surface of the support layer 110. The first conductive layer 120 is provided over the entire surface of the support layer 110.

[0033] In this embodiment, the first conductive layer 120 is located on the side of the winding axis Z when viewed from the support layer 110. However, the first conductive layer 120 may be located on the side opposite to the winding axis Z when viewed from the support layer 110.

[0034] The second conductive layer 130 is laminated on the support layer 110 opposite to the first conductive layer 120. That is, the second conductive layer 130 is provided on the other side of the support layer 110. The second conductive layer 130 is provided over the entire other side.

[0035] The thickness of the first conductive layer 120 and the thickness of the second conductive layer 130 are thinner than the thickness of the support layer 110. The thickness of the first conductive layer 120 and 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, in order to reduce the overall thickness of the electrode body 10. The thickness of the first conductive layer 120 and the second conductive layer 130 may be, for example, 0.1 μm or more, in order to prevent the electrical resistance of the first conductive layer 120 and the second conductive layer 130 from becoming too high. Note that if the thickness of the first conductive layer 120 and the second conductive layer 130 are 5 μm or less, it is difficult to directly weld the first conductive layer 120 and the second conductive layer 130 to each other or to directly join them to each other by ultrasonic welding.

[0036] The method for forming the first conductive layer 120 and the second conductive layer 130 is not particularly limited. Typically, the first conductive layer 120 and the second conductive layer 130 may be provided on the support layer 110 by a vapor deposition method or the like. The first conductive layer 120 and the second conductive layer 130 may be composed of metal films. In this case, the first conductive layer 120 and the second conductive layer 130 may be bonded to the support layer 110 via a resin adhesive.

[0037] Furthermore, the first conductive layer 120 and the second conductive layer 130 are typically made of a metal containing aluminum. As a result, the first current collector 100A, which includes the first conductive layer 120 and the second conductive layer 130, can be suitably used as a positive electrode current collector. The first current collector 100A may also be a negative electrode current collector, and the first conductive layer 120 and the second conductive layer 130 may be made of a metal containing copper.

[0038] As shown in Figure 3, the multiple tab portions 140 are aligned in the winding direction DR of the electrode body 10. The multiple tab portions 140 are spaced apart from each other.

[0039] As shown in Figure 2, the multiple tab portions 140 are arranged in the third direction D3. The multiple tab portions 140 are joined to each other by ultrasonic bonding or the like. Furthermore, as shown in Figure 1, the multiple tab portions 140 are joined to the first connecting member 40A by ultrasonic bonding or the like. As a result, the first external terminal 30A is electrically connected to the tab portion 140. The configuration of each of the multiple tab portions 140 will be described below.

[0040] The tab portion 140 consists of one or more film-like members. Typically, the tab portion 140 consists of a metal film containing aluminum or copper.

[0041] As shown in Figures 3 to 6, the tab portion 140 includes a tab body portion 141, a plurality of heat dissipation portions 142, and an auxiliary portion 145.

[0042] The tab body portion 141 is connected to the first conductive layer 120. Typically, the tab body portion 141 is directly bonded to the first conductive layer 120. The tab body portion 141 is bonded to the first conductive layer 120, for example, by ultrasonic welding. The tab body portion 141 extends along a first direction D1 on the first conductive layer 120. The tab body portion 141 extends away from the first conductive layer 120. The extension direction DE of the tab body portion 141 is substantially parallel to the first direction D1.

[0043] The tab body portion 141 is configured to be connectable to other conductive members so as to be electrically connected to them. In this embodiment, the tab body portion 141 is joined to the first connecting member 40A by ultrasonic bonding. The tab body portion 141 may also be directly joined to the first external terminal 30A.

[0044] As shown in Figure 3, the heat dissipation section 142 is connected to the tab body section 141 in the winding direction DR. The heat dissipation section 142 is formed from a single component integrated with the tab body section 141. In this embodiment, two heat dissipation sections 142 are located on either side of the tab body section 141 in the winding direction DR. The heat dissipation section 142 is shorter than the tab body section 141 in the extension direction DE of the tab body section 141.

[0045] As shown in Figure 6, the heat dissipation section 142 is located on the opposite side from the support layer 110 when viewed from the first conductive layer 120. The heat dissipation section 142 is joined to the first conductive layer 120 by ultrasonic welding.

[0046] As shown in Figure 4, the heat dissipation section 142 is bent multiple times. The tab body section 141 is either not bent or bent fewer times than the heat dissipation section 142. Typically, as shown in Figure 2, the tab body section 141 is bent fewer times than the heat dissipation section 142. This facilitates joining the tab body section 141 to other conductive members (first connecting member 40A).

[0047] As shown in Figures 4 and 6, the heat dissipation section 142 includes a plurality of valley folds 143 and a plurality of mountain folds 144.

[0048] Multiple valley folds 143 and multiple mountain folds 144 are arranged alternately. Multiple valley folds 143 protrude toward the first conductive layer 120 in the thickness direction DT. Multiple mountain folds 144 protrude toward the opposite side from the first conductive layer 120 in the thickness direction DT. Multiple valley folds 143 extend along the extension direction DE. Multiple valley folds 143 extend throughout the entire heat dissipation section 142. Multiple mountain folds 144 extend along the extension direction DE. Multiple mountain folds 144 extend throughout the entire heat dissipation section 142. Multiple valley folds 143 are directly bonded to the first conductive layer 120 by ultrasonic bonding.

[0049] The auxiliary portion 145 is joined to the second conductive layer 130 by ultrasonic welding. The auxiliary portion 145 extends along the first direction D1 on the second conductive layer 130. The auxiliary portion 145 extends from the second conductive layer 130 in the extension direction DE. The auxiliary portion 145 is also joined to the tab body portion 141 and the heat dissipation portion 142 (valley fold portion 143) by ultrasonic welding. In the extension direction DE, the auxiliary portion 145 is shorter than both the tab body portion 141 and the heat dissipation portion 142 (valley fold portion 143). In addition, the auxiliary portion 145 is aligned with the tab body portion 141 and the heat dissipation portion 142 in the thickness direction DT. Furthermore, in this embodiment, the auxiliary portion 145 is formed from a metal film separate from the tab body portion 141 and the heat dissipation portion 142.

[0050] The thickness of each of the tab body 141, heat dissipation portion 142, and auxiliary portion 145 is greater than the thickness of the first conductive layer 120 and the second conductive layer 130, respectively. The thickness of each of the tab body 141, heat dissipation portion 142, and auxiliary portion 145 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The thickness of each of these is not particularly limited as long as it has the desired rigidity. The thickness of each of these may be, for example, 2 μm or more.

[0051] As shown in Figures 2, 5, and 6, the first active material layer 200A is laminated on the first conductive layer 120 and the second conductive layer 130. The first active material layer 200A is a positive electrode active material layer, but it may also be a negative electrode active material layer. The first active material layer 200A is separated from the tab portion 140.

[0052] The separator 12 is stacked on the first active material layer 200A in the radial direction centered on the winding axis Z.

[0053] The first protective portion 400 is made of an electrically insulating ceramic. As shown in Figures 5 and 6, the first protective portion 400 covers a portion of the first active material layer 200A laminated on the first conductive layer 120 on the DE side in the extension direction. The first protective portion 400 covers the entire surface of the first conductive layer 120 between the first active material layer 200A and the tab body portion 141 and the heat dissipation portion 142. The first protective portion 400 is also partially positioned between the first conductive layer 120 and the tab body portion 141 and the heat dissipation portion 142.

[0054] The second protective portion 500 is made of an electrically insulating ceramic. The second protective portion 500 covers a portion of the first active material layer 200A, which is laminated on the second conductive layer 130, on the DE side in the extension direction. The second protective portion 500 covers the entire surface of the second conductive layer 130 between the first active material layer 200A and the auxiliary portion 145. The second protective portion 500 is also partially positioned between the second conductive layer 130 and the auxiliary portion 145.

[0055] As shown in Figure 2, the second electrode 11B is laminated on the first active material layer 200A via a separator 12 in the radial direction. In this embodiment, the electrode body 10 includes multiple separators 12, but it may also include a single separator 12.

[0056] The second electrode 11B includes a second current collector 100B and a second active material layer 200B. The second current collector 100B is drawn out from between the second active material layers 200B to one side in the first direction D1. The second current collector 100B is joined to the second connecting member 40B by ultrasonic welding (see Figure 1).

[0057] The second current collector 100B is made of, for example, a metal film. The second current collector 100B is made of, for example, a metal containing copper. This allows the second current collector 100B to be suitably used as a negative electrode current collector. In the case where the first current collector 100A is a negative electrode current collector and the second current collector 100B is a positive electrode current collector, the second current collector 100B may be made of a metal containing aluminum.

[0058] The second active material layer 200B is laminated on both sides of the second current collector 100B. In this embodiment, the second electrode 11B is the negative electrode. Therefore, the second active material layer 200B is the negative electrode active material layer. The second active material layer 200B may also be the positive electrode active material layer.

[0059] As described above, the first current collector 100A according to Embodiment 1 comprises a support layer 110, a first conductive layer 120, and a tab portion 140. The support layer 110 is made of an electrically insulating resin composition. The first conductive layer 120 is laminated on the support layer 110. The tab portion 140 is made of a film-like material. The tab portion 140 includes a tab body portion 141 and a heat dissipation portion 142. The tab body portion 141 is connected to the first conductive layer 120. The tab body portion 141 is configured to be connectable to other conductive members so as to be electrically connected to them. The heat dissipation portion 142 is bent multiple times.

[0060] As described above, the film-like material constituting the tab portion 140 is folded multiple times in the heat dissipation portion 142, thereby increasing the surface area of ​​the heat dissipation portion 142 in a limited space (for example, inside the case 20 of the battery 1). This allows for effective heat dissipation of the heat generated at the connection between the first conductive layer 120 and the tab body portion 141 when power is applied. Therefore, localized heat generation of the electrode body 10 can be suppressed.

[0061] Furthermore, in this embodiment, the tab body portion 141 extends away from the first conductive layer 120. The heat dissipation portion 142 includes a plurality of valley folds 143 and a plurality of mountain folds 144. The plurality of valley folds 143 and the plurality of mountain folds 144 are arranged alternately with respect to each other. The plurality of valley folds 143 protrude toward the first conductive layer 120. The plurality of mountain folds 144 protrude toward the opposite side from the first conductive layer 120. The plurality of valley folds 143 extend along the extension direction DE of the tab body portion 141. The plurality of mountain folds 144 extend along the extension direction DE.

[0062] As described above, since the multiple valley folds 143 and multiple mountain folds 144 extend along the extension direction DE, the heat dissipation section 142 becomes relatively compact in the orthogonal direction DX (winding direction DR in this embodiment) perpendicular to the extension direction DE. Consequently, the entire tab section 140 becomes compact in the orthogonal direction DX, making it easy to connect the tab body section 141 to the first conductive layer 120.

[0063] Furthermore, in this embodiment, the tab body portion 141 is either not bent or bent fewer times than the heat dissipation portion 142.

[0064] With the above configuration, since the tab body portion 141 includes many relatively flat parts, it becomes easy to join the tab body portion 141 to other conductive members.

[0065] (Embodiment 2) Next, the first current collector and battery according to Embodiment 2 of this disclosure will be described. Note that some configurations and effects similar to those in Embodiment 1 may not be repeated in the description.

[0066] Figure 7 is an unfolded view of the first electrode in Embodiment 2. Figure 8 is a partial cross-sectional view of the first electrode in Figure 7, viewed in the direction of the arrow VIII-VIII.

[0067] As shown in Figures 7 and 8, in Embodiment 2, the multiple valley folds 143a extend along the orthogonal direction DX which is perpendicular to the extension direction DE of the tab body portion 141. The multiple mountain folds 144a extend along the orthogonal direction DX.

[0068] As described above, since the multiple valley folds 143a and multiple mountain folds 144a extend along the orthogonal direction DX, the heat dissipation portion 142a can be formed by compressing a relatively long film-like member in the extension direction DE. Furthermore, since the tab body portion 141 extends from the first conductive layer 120, the tab body portion 141 is also a relatively long member in the extension direction DE. Therefore, the film-like member constituting the tab portion 140 exhibits a small change in length in the extension direction DE throughout the orthogonal direction DX. As a result, the film-like member constituting the tab portion 140 can be easily cut from the raw film, providing a first current collector 100A that is easy to manufacture.

[0069] In this embodiment, the heat dissipation section 142a is not directly connected to the tab body section 141. The heat dissipation section 142a is not joined to the first conductive layer 120 by ultrasonic welding.

[0070] In this embodiment, the tab portion 140 further includes a joint portion 146a. The joint portion 146a is connected to the tab body portion 141 in the winding direction DR. The joint portion 146a is connected to the heat dissipation portion 142a at its end on the extension direction DE side. The joint portion 146a is aligned with the heat dissipation portion 142a. The joint portion 146a is joined to the first conductive layer 120 by ultrasonic bonding.

[0071] In the above-described embodiment, the combinatable configurations may be combined with each other.

[0072] The embodiments 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 within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]

[0073] 1 Battery, 10 Electrode body, 11A First electrode, 11B Second electrode, 12 Separator, 20 Case, 21 Case body, 21a Bottom wall, 21b Peripheral wall, 22 Lid, 22a First connecting hole, 22b Second connecting hole, 30A First external terminal, 30B Second external terminal, 40A First connecting member, 40B Second connecting member, 100A First current collector, 100B Second current collector, 110 Support layer, 120 First conductive layer, 130 Second conductive layer, 140 Tab section, 141 Tab body section, 142,142a Heat dissipation section, 143,143a Valley fold section, 144,144a Mountain fold section, 145 Auxiliary section, 146a Joint section, 200A First active material layer, 200B Second active material layer, 400 First protective section, 500 second protective section, D1 first direction, D2 second direction, D3 third direction, DE extension direction, DR winding direction, DT thickness direction, DX orthogonal direction, Z winding axis.

Claims

1. It is a current collector, Supporting layer, A conductive layer, Equipped with a tab section, The support layer is made of an electrically insulating resin composition. The conductive layer is laminated on the support layer, The tab portion is made of a film-like material, The tab portion includes a tab body portion and a heat dissipation portion. The tab body is connected to the conductive layer, The tab body is configured to be connectable to other conductive members so as to be electrically connected to them. The heat dissipation section is a current collector that has been bent multiple times.

2. The tab body extends away from the conductive layer, The heat dissipation section includes a plurality of valley folds and a plurality of mountain folds, The aforementioned plurality of valley folds and the plurality of mountain folds are arranged alternately with respect to each other. The aforementioned multiple valley folds protrude toward the conductive layer side. The aforementioned multiple mountain-fold portions protrude on the side opposite to the conductive layer, The aforementioned plurality of valley folds extend along the extension direction of the tab body portion, The current collector according to claim 1, wherein the plurality of mountain-fold portions extend along the extension direction.

3. The tab body extends away from the conductive layer, The heat dissipation section includes a plurality of valley folds and a plurality of mountain folds, The aforementioned plurality of valley folds and the plurality of mountain folds are arranged alternately with respect to each other. The aforementioned multiple valley folds protrude toward the conductive layer side. The aforementioned multiple mountain-fold portions protrude on the side opposite to the conductive layer, The aforementioned plurality of valley folds extend along a direction perpendicular to the extension direction of the tab body, The current collector according to claim 1, wherein the plurality of mountain-fold portions extend along the orthogonal direction.

4. The current collector according to claim 2 or 3, wherein the tab body is not bent, or is bent fewer times than the number of times the heat dissipation portion is bent.

5. It is a battery, Electrode body and Equipped with external terminals, The electrode body includes a first electrode, a second electrode, and a separator. The first electrode comprises a current collector and an active material layer. The current collector includes a support layer, a conductive layer, and a tab portion. The support layer is made of an electrically insulating resin composition. The conductive layer is laminated on the support layer, The tab portion is made of a film-like material, The tab portion includes a tab body portion and a heat dissipation portion. The tab body is connected to the conductive layer, The tab body is configured to be connectable to other conductive members so as to be electrically connected to them. The heat dissipation section is bent multiple times. The active material layer is laminated on the conductive layer, The separator is laminated on the active material layer, The second electrode is laminated on the active material layer via the separator, The external terminal is a battery that is electrically connected to the tab body.

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