Current collector and battery

Abstract

To improve the adhesion between the support layer and the conductive layer of the current collector. [Solution] The current collector 100A comprises a support layer 110, a first conductive layer 120, and a first adhesive layer 130. The support layer 110 is made of an electrically insulating resin composition. The first conductive layer 120 is laminated on the support layer 110 via the first adhesive layer 130. The first conductive layer 120 includes a first surface 121. The first surface 121 faces the first adhesive layer 130. The first surface 121 is subjected to a chemical surface roughening treatment.

Description

Technical Field

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

Background Art

[0002] Japanese Patent Application 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 conductive layer is formed by a method of vacuum deposition, mechanical roll pressing, or adhesion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is room for improvement in improving the adhesive force between the support layer and the conductive layer in the current collector. The present disclosure has been made in view of this problem, and an object thereof is to provide a current collector in which the adhesive force between the support layer and the conductive layer is improved, and a battery including the same.

Means for Solving the Problems

[0005] A current collector according to an aspect of the present disclosure includes a support layer, a first conductive layer, and a first adhesive layer. The support layer is made of a resin composition having electrical insulation. The first conductive layer is laminated on the support layer via the first adhesive layer. The first conductive layer includes a first surface. The first surface faces the first adhesive layer. The first surface is subjected to a chemical surface roughening treatment.

[0006] 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 first conductive layer, and a first adhesive layer. The support layer is made of an electrically insulating resin composition. The first conductive layer is laminated to the support layer via the first adhesive layer. The first conductive layer includes a first surface and a second surface. The first surface faces the first adhesive layer. The first surface is chemically surface roughened. The second surface faces away from the first surface. The active material layer is laminated on the second surface. 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 first conductive layer. [Effects of the Invention]

[0007] According to this disclosure, the adhesion between the support layer and the conductive layer can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a battery according to one embodiment. [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 one embodiment. [Figure 4] This is a partial cross-sectional view of the first electrode in Figure 3, as seen in the direction of the IV-IV line arrow. [Modes for carrying out the invention]

[0009] Hereinafter, a current collector and a battery according to one embodiment of the present 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.

[0010] Figure 1 is a cross-sectional view showing a battery according to one embodiment. 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.

[0011] As shown in Figure 1, a battery 1 according to one embodiment 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.

[0012] 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.

[0013] 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.

[0014] The lid 22 is joined to the peripheral wall 21b by welding or other means so as to close the opening in the peripheral wall 21b. The lid 22 has a first connecting hole 22a and a second connecting hole 22b formed therein.

[0015] 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 are conductive. At least a portion of the first connecting member 40A and the second connecting member 40B are located inside the case 20.

[0016] The first external terminal 30A or the first connecting member 40A is inserted into the first connecting 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.

[0017] The second external terminal 30B or the second connecting member 40B is inserted into the second connecting 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.

[0018] In addition, in the present 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.

[0019] Next, the electrode body 10 will be described. The battery 1 according to the present 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.

[0020] In the following, one electrode body 10 among the plurality of electrode bodies 10 will be described. Note that each of the plurality of electrode bodies 10 may have the configuration shown below.

[0021] FIG. 2 is a cross-sectional view of the electrode body in FIG. 1 as viewed in the direction of the arrow along line II-II. As shown in FIGS. 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 the periphery of the winding axis Z. Thus, in the present embodiment, the electrode body 10 is a so-called wound electrode body. However, the electrode body 10 may be a laminated electrode body in which the first electrode 11A, the second electrode 11B, and the separator 12 are laminated in one direction (for example, the third direction D3). In FIG. 2, the separator 12 is schematically shown by a broken line.

[0022] 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 via one or more separators 12. In the present 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.

[0023] 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 the passage of ions between the first electrode 11A and the second electrode 11B. The ions are, for example, lithium ions. The separator 12 has electrical insulation.

[0024] FIG. 3 is a developed view of the first electrode in one embodiment. That is, FIG. 3 shows the state before the first electrode 11A is wound. FIG. 4 is a partial cross-sectional view of the first electrode in FIG. 3 as viewed in the direction of the arrow along line IV-IV.

[0025] As shown in FIGS. 2 to 4, the first electrode 11A includes a first current collector 100A, a pair of first active material layers 200A, a first protection part 400, and a second protection part 500.

[0026] The first current collector 100A includes a support layer 110, a first conductive layer 120, a first adhesive layer 130, a second conductive layer 140, a second adhesive layer 150, a plurality of tab portions 160, and a plurality of conductive auxiliary portions 170.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The first conductive layer 120 is laminated on the support layer 110 via the first adhesive layer 130. The first conductive layer 120 is provided on one side of the support layer 110. When viewed from the thickness direction DT, the first conductive layer 120 is provided so as to cover the entirety of one side of the support layer 110.

[0032] 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.

[0033] The first conductive layer 120 includes a first surface 121 and a second surface 122. The first surface 121 is oriented toward the first adhesive layer 130. The first surface 121 is in contact with the first adhesive layer 130. Typically, the entire first surface 121 is in contact with the first adhesive layer 130.

[0034] Surface 121 has been subjected to chemical surface roughening treatment. Examples of chemical surface roughening treatments include etching or anodizing.

[0035] The arithmetic mean roughness Ra of the first surface 121 is preferably, for example, 0.5 μm or less. Having an arithmetic mean roughness Ra of 0.5 μm or less facilitates the anchoring effect of the first adhesive layer 130. The arithmetic mean roughness Ra of the first surface 121 may also be 0.2 μm or less, or 0.1 μm or less. For example, the arithmetic mean roughness Ra of the first surface 121 may be 0.01 μm or more.

[0036] The second surface 122 faces away from the first surface 121. The second surface 122 is in contact with one of the first active material layers 200A. The second surface 122 is in contact with multiple tab portions 160.

[0037] The second surface 122 is subjected to a surface roughening treatment. Examples of surface roughening treatments include laser surface treatment, sandblasting, or the chemical surface roughening treatment described above. The second surface 122 may also be subjected to surface modification treatment by corona discharge treatment, plasma treatment, or UV irradiation treatment.

[0038] The arithmetic mean roughness Ra of the second surface 122 is greater than the arithmetic mean roughness Ra of the first surface 121. Preferably, the arithmetic mean roughness Ra of the second surface 122 is 1 μm or more. When the arithmetic mean roughness Ra of the second surface 122 is 1 μm or more, the active material particles contained in the first active material layer 200A are more easily embedded.

[0039] The first adhesive layer 130 is provided on one surface of the support layer 110. The first adhesive layer 130 is provided over the entire surface of one side of the support layer 110.

[0040] The second conductive layer 140 and the second adhesive layer 150 are located on the opposite side from the first conductive layer 120 and the first adhesive layer 130 when viewed from the support layer 110.

[0041] The second conductive layer 140 is laminated to the support layer 110 via the second adhesive layer 150. The second conductive layer 140 is provided on the other side of the support layer 110. The second conductive layer 140 is provided so as to cover the entire other side of the support layer 110 when viewed from the thickness direction DT.

[0042] The second conductive layer 140 includes a third surface 141 and a fourth surface 142. The third surface 141 is oriented toward the second adhesive layer 150. The third surface 141 is in contact with the second adhesive layer 150. Typically, the entire third surface 141 is in contact with the second adhesive layer 150.

[0043] Surface 3, section 141, has been subjected to chemical surface roughening treatment. Examples of chemical surface roughening treatments include etching or anodizing.

[0044] The arithmetic mean roughness Ra of the third surface 141 is preferably 0.5 μm or less. Having an arithmetic mean roughness Ra of 0.5 μm or less facilitates the anchoring effect of the second adhesive layer 150. The arithmetic mean roughness Ra of the third surface 141 may also be 0.2 μm or less or 0.1 μm or less. For example, the arithmetic mean roughness Ra of the third surface 141 should be 0.01 μm or more.

[0045] The fourth surface 142 faces away from the third surface 141. The fourth surface 142 is in contact with the other first active material layer 200A. The fourth surface 142 is in contact with a plurality of conductive auxiliary parts 170.

[0046] The fourth surface 142 is subjected to a surface roughening treatment. Examples of surface roughening treatments include laser surface treatment, sandblasting, or the chemical surface roughening treatment described above. The fourth surface 142 may also be subjected to surface modification treatment by corona discharge treatment, plasma treatment, or UV irradiation treatment.

[0047] The arithmetic mean roughness Ra of the fourth surface 142 is greater than the arithmetic mean roughness Ra of the third surface 141. Preferably, the arithmetic mean roughness Ra of the fourth surface 142 is, for example, 1 μm or more. When the arithmetic mean roughness Ra of the fourth surface 142 is 1 μm or more, the active material particles contained in the first active material layer 200A are more easily embedded.

[0048] The second adhesive layer 150 is provided on the other surface of the support layer 110. The second adhesive layer 150 is provided over the entire other surface of the support layer 110.

[0049] The method for forming the first conductive layer 120 and the second conductive layer 140 is not particularly limited. In this embodiment, the first conductive layer 120 and the second conductive layer 140 are typically made of a metal film. The metal film may typically be manufactured by extrusion molding. Also, the first conductive layer 120 and the second conductive layer 140 are typically made of a metal containing aluminum. As a result, the first current collector 100A, which has the first conductive layer 120 and the second conductive layer 140, 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 140 may be made of a metal containing copper.

[0050] The thickness of the first conductive layer 120 and the thickness of the second conductive layer 140 are thinner than the thickness of the support layer 110. The thickness of the first conductive layer 120 and the second conductive layer 140 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 140 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 140 from becoming too high. Note that if the thickness of the first conductive layer 120 and the second conductive layer 140 are 5 μm or less, it is difficult to directly weld the first conductive layer 120 and the second conductive layer 140 to each other or to directly join them to each other by ultrasonic welding.

[0051] Furthermore, the first adhesive layer 130 and the second adhesive layer 150 are not particularly limited as long as they have adhesive properties. Typically, the first adhesive layer 130 and the second adhesive layer 150 consist of an adhesive containing a resin. Examples of resins that can be included in the adhesive include phenolic resin, epoxy resin, melamine resin, urea resin, urethane resin, alkyd resin, silicone resin, unsaturated polyester resin, polyolefin resin, polyimide, acrylic resin, etc., and can be used individually or in combination of two or more. Among these, it is preferable to use at least one selected from the group consisting of epoxy resin, urethane resin, silicone resin, polyolefin resin, and acrylic resin. By using resins from this group, a more suitable adhesive strength can be achieved.

[0052] The thickness of the first adhesive layer 130 and the second adhesive layer 150 may be, for example, 0.5 μm or more, 1 μm or more, 2 μm or more, or 3 μm or more. The thickness of the first adhesive layer 130 and the second adhesive layer 150 may be, for example, 10 μm or less, 5 μm or less, or 3 μm or less.

[0053] As shown in Figure 3, the multiple tab portions 160 are aligned in the winding direction DR of the electrode body 10. The multiple conductive auxiliary portions 170 are aligned in the winding direction DR of the electrode body 10. The multiple tab portions 160 are spaced apart from each other. The multiple conductive auxiliary portions 170 are spaced apart from each other. The multiple conductive auxiliary portions 170 are aligned with the multiple tab portions 160 in a one-to-one correspondence in the thickness direction DT.

[0054] As shown in Figure 2, the multiple tab portions 160 are arranged in the third direction D3. The multiple tab portions 160 are joined to each other by ultrasonic bonding or the like. Furthermore, as shown in Figure 1, the multiple tab portions 160 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 160. Consequently, the first external terminal 30A is electrically connected to the first conductive layer 120 and the second conductive layer 140. The configurations of each of the multiple tab portions 160 and each of the multiple conductive auxiliary portions 170 will be described below.

[0055] The tab portion 160 is connected to the first conductive layer 120. Typically, the tab portion 160 is directly bonded to the first conductive layer 120. The tab portion 160 is bonded to the first conductive layer 120, for example, by ultrasonic welding. The tab portion 160 extends along a first direction D1 on the first conductive layer 120. The tab portion 160 extends away from the first conductive layer 120. The extension direction DE of the tab portion 160 is substantially parallel to the first direction D1. Alternatively, the tab portion 160 may be directly bonded to the first external terminal 30A.

[0056] The conductive auxiliary portion 170 is connected to the second conductive layer 140. Typically, the conductive auxiliary portion 170 is directly bonded to the second conductive layer 140. The conductive auxiliary portion 170 is bonded to the second conductive layer 140, for example, by ultrasonic welding. The end of the conductive auxiliary portion 170 in the extension direction DE is bonded to the tab portion 160 by ultrasonic welding.

[0057] The tab portion 160 and the conductive auxiliary portion 170 are made of a film-like material. Typically, the tab portion 160 and the conductive auxiliary portion 170 are made of a metal film containing aluminum or copper.

[0058] The thickness of the tab portion 160 and the conductive auxiliary portion 170 is greater than the thickness of the first conductive layer 120 and the second conductive layer 140, respectively. The thickness of the tab portion 160 and the conductive auxiliary portion 170 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.

[0059] The first active material layer 200A is laminated on the second surface 122 and the fourth surface 142, respectively. The first active material layer 200A contains a plurality of binder particles and a plurality of active material particles. Each of these plurality of active material particles typically contains a positive electrode active material. Examples of positive electrode active materials include LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(NiCoMn)O2, Li(NiCoAl)O2, LiFePO4, and LiMn 0.5 Fe 0.5 The material may contain at least one selected from the group consisting of PO4, LiMnPO4, LiNiPO4, and LiCoPO4. For example, "(NiCoMn)" in "Li(NiCoMn)O2" indicates that the sum of the composition ratios in parentheses is 1. However, each of these multiple active material particles may contain a negative electrode active material such as graphite particles or silicon oxide particles. The average particle diameter D50 of the multiple active material particles may be, for example, 0.01 μm or more, 0.1 μm or more, 0.5 μm or more, 1 μm or more, or 5 μm or more, and may be 50 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, or 7.5 μm or less. The separator 12 is laminated on the first active material layer 200A in the radial direction centered on the winding axis Z.

[0060] The first protective portion 400 is made of an electrically insulating ceramic. The first protective portion 400 covers a portion of the first active material layer 200A, which is 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 portion 160. The first protective portion 400 is also partially positioned between the first conductive layer 120 and the tab portion 160.

[0061] 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 140, on the DE side in the extension direction. The second protective portion 500 covers the entire surface of the second conductive layer 140 between the first active material layer 200A and the conductive auxiliary portion 170. The second protective portion 500 is also partially positioned between the second conductive layer 140 and the conductive auxiliary portion 170.

[0062] 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.

[0063] 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).

[0064] 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. Furthermore, the second current collector 100B may have the same configuration as the first current collector 100A.

[0065] 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.

[0066] As described above, a first current collector 100A according to one embodiment of the present disclosure comprises a support layer 110, a first conductive layer 120, and a first adhesive layer 130. The support layer 110 is made of an electrically insulating resin composition. The first conductive layer 120 is laminated on the support layer 110 via the first adhesive layer 130. The first conductive layer 120 includes a first surface 121. The first surface 121 faces the first adhesive layer 130. The first surface 121 is subjected to a chemical surface roughening treatment.

[0067] According to the above configuration, the chemical surface roughening treatment applied to the first surface 121 allows the first adhesive layer 130 to penetrate into the recesses of the first surface 121. In other words, an anchoring effect of the first adhesive layer 130 is generated. This improves the adhesive strength between the support layer 110 and the first conductive layer 120.

[0068] In this embodiment, the first conductive layer 120 further includes a second surface 122. The second surface 122 faces away from the first surface 121. The second surface 122 is surface-roughened.

[0069] With the above configuration, the active material particles contained in the first active material layer 200A can easily fit into the recesses of the second surface 122. Therefore, the adhesion between the second surface 122 and the first active material layer 200A further laminated on the second surface 122 can be improved.

[0070] Furthermore, in this embodiment, the arithmetic mean roughness Ra of the second surface 122 is greater than the arithmetic mean roughness Ra of the first surface 121. With this configuration, the first surface 121 and the second surface 122 can each be given an appropriate roughness according to the purpose. This is because it is preferable that the recess for improving adhesion with the first active material layer 200A be larger than the size of the recess for generating the anchoring effect.

[0071] In this embodiment, the first current collector 100A further comprises a second conductive layer 140 and a second adhesive layer 150. The second conductive layer 140 and the second adhesive layer 150 are located on the opposite side from the first conductive layer 120 and the first adhesive layer 130 when viewed from the support layer 110. The second conductive layer 140 is laminated to the support layer 110 via the second adhesive layer 150. The second conductive layer 140 includes a third surface 141 and a fourth surface 142. The third surface 141 faces the second adhesive layer 150. The third surface 141 is chemically surface roughened. The fourth surface 142 faces the opposite side from the third surface 141. The fourth surface 142 is surface roughened. The arithmetic mean roughness Ra of the fourth surface 142 is greater than the arithmetic mean roughness Ra of the third surface 141.

[0072] According to the above configuration, the chemical surface roughening treatment applied to the third surface 141 allows the second adhesive layer 150 to penetrate into the recesses of the third surface 141. In other words, an anchoring effect of the second adhesive layer 150 is generated. This improves the adhesion between the support layer 110 and the second conductive layer 140. Furthermore, the surface roughening treatment applied to the fourth surface 142 makes it easier for the active material particles contained in the first active material layer 200A to fit into the recesses of the fourth surface 142. Therefore, the adhesion between the fourth surface 142 and the first active material layer 200A further laminated on the fourth surface 142 can be improved. Moreover, since the arithmetic mean roughness Ra of the fourth surface 142 is greater than the arithmetic mean roughness Ra of the third surface 141, the third surface 141 and the fourth surface 142 can be made to have an appropriate roughness according to the purpose.

[0073] In the above-described embodiments, the combinable configurations may be combined with each other.

[0074] 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]

[0075] 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, 121 First surface, 122 Second surface, 130 First adhesive layer, 140 Second conductive layer, 141 Third surface, 142 Fourth surface, 150 Second adhesive layer, 160 Tab part, 170 Conductive auxiliary part, 200A First active material layer, 200B Second active material layer, 400 First protective part, 500 Second protective section, D1 first direction, D2 second direction, D3 third direction, DE extension direction, DR winding direction, DT thickness direction, Z winding axis.

Claims

1. It is a current collector, Supporting layer, First conductive layer and A first adhesive layer is provided, The support layer is made of an electrically insulating resin composition. The first conductive layer is laminated on the support layer via the first adhesive layer. The first conductive layer includes a first surface, The first surface is facing the first adhesive layer, The first surface is a current collector that has undergone chemical surface roughening treatment.

2. The first conductive layer further includes a second surface, The second face is oriented opposite to the first face. The current collector according to claim 1, wherein the second surface is subjected to a surface roughening treatment.

3. The current collector according to claim 2, wherein the arithmetic mean roughness of the second surface is greater than the arithmetic mean roughness of the first surface.

4. The second conductive layer, Further comprising a second adhesive layer, The second conductive layer and the second adhesive layer are located on the opposite side from the first conductive layer and the first adhesive layer when viewed from the support layer. The second conductive layer is laminated on the support layer via the second adhesive layer. The second conductive layer includes a third surface and a fourth surface, The third surface is facing the second adhesive layer, The third surface has been subjected to chemical surface roughening treatment. The fourth face is oriented opposite to the third face. The fourth surface has been subjected to a surface roughening treatment. The current collector according to claim 3, wherein the arithmetic mean roughness of the fourth surface is greater than the arithmetic mean roughness of the third surface.

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 first conductive layer, and a first adhesive layer. The support layer is made of an electrically insulating resin composition. The first conductive layer is laminated on the support layer via the first adhesive layer. The first conductive layer includes a first surface and a second surface, The first surface is facing the first adhesive layer, The first surface has been subjected to a chemical surface roughening treatment. The second face is oriented opposite to the first face. The active material layer is laminated on the second surface, 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 electrically connected to the first conductive layer, and is a battery.

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