Current collector and battery

Abstract

The invention relates to a current collector and a battery. The current collector includes a support portion and a conductive portion. The support part is made of a resin composition having electrical insulating properties. The conductive portion includes a first conductive layer, a second conductive layer, and a third conductive layer. The first conductive layer and the second conductive layer extend from the support portion. The third conductive layer is disposed between the first conductive layer and the second conductive layer, is bonded to both the first conductive layer and the second conductive layer, and extends from between the first conductive layer and the second conductive layer.

Description

Technical Field

[0001] This disclosure relates to current collectors and batteries. Background Technology

[0002] Japanese Patent Application Publication No. 2024-510696 discloses an electrode plate. The electrode plate includes a current collector, an active material layer, and an electrical connection member. The active material layer is disposed on one surface of the current collector. The electrical connection member is electrically connected to the current collector. The current collector includes a support layer and a conductive layer. The conductive layer is disposed on one surface of the support layer. The electrical connection member and the current collector are welded together at the edge of the current collector; this welded connection area is referred to as a relay welding area. Summary of the Invention

[0003] The current collector connected to the electrical connection components is relatively thick. This increases the overall volume ratio of the current collector in the battery, resulting in a lower energy density. Furthermore, if the active material layer is increased and the relay welding area is decreased to improve the battery's energy density, the resistance of the relay welding area increases.

[0004] This disclosure was made in view of the above-mentioned problems, and its object is to provide a current collector that is thin and can reduce the resistance of the conductive part.

[0005] One aspect of this disclosure provides a current collector comprising a support portion and a conductive portion. The support portion is made of a resin composition having electrical insulating properties. The conductive portion includes a first conductive layer, a second conductive layer, and a third conductive layer. The first and second conductive layers extend from the support portion. The third conductive layer is disposed between the first and second conductive layers, bonded to both the first and second conductive layers, and extends from between the first and second conductive layers.

[0006] In one aspect of the current collector of this disclosure, it is preferred that the third conductive layer is separated from the support portion.

[0007] In one aspect of the current collector of this disclosure, it is preferred that the thickness of the third conductive layer is substantially equal to the thickness of the support portion.

[0008] In one aspect of the current collector of this disclosure, it is preferred that the thickness of the first conductive layer is thinner than the thickness of the third conductive layer. The thickness of the second conductive layer is thinner than the thickness of the third conductive layer.

[0009] One aspect of the battery disclosed herein includes an electrode body, an external terminal, and a connecting portion. 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 portion and a conductive portion. The support portion is made of an electrically insulating resin composition. The conductive portion includes a first conductive layer, a second conductive layer, and a third conductive layer. The first and second conductive layers extend from the support portion. The third conductive layer is disposed between the first and second conductive layers, bonded to both the first and second conductive layers, and extends between the first and second conductive layers. The active material layer is laminated on the first conductive layer. The separator is laminated on the active material layer. The second electrode is laminated on the active material layer across the separator. The external terminal is electrically connected to the connecting portion. The connecting portion is bonded to the third conductive layer.

[0010] In one aspect of the battery disclosed herein, it is preferred that the third conductive layer is separated from the support portion.

[0011] In one aspect of the battery disclosed herein, it is preferred that the thickness of the third conductive layer is substantially equal to the thickness of the support portion.

[0012] In one aspect of the battery disclosed herein, it is preferred that the thickness of the first conductive layer is thinner than the thickness of the third conductive layer. The thickness of the second conductive layer is thinner than the thickness of the third conductive layer.

[0013] In one aspect of the battery disclosed herein, it is preferred that the support portion has a support edge. The support edge faces the extending direction. The extending direction is the direction in which the first conductive layer extends from the support portion. The active material layer has an active material edge. The active material edge faces the extending direction. The active material edges are arranged side by side with the support edge in the thickness direction of the support portion.

[0014] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description relating to the invention, which is understood in conjunction with the accompanying drawings. Attached Figure Description

[0015] Figure 1 This is a perspective view of the battery according to Embodiment 1.

[0016] Figure 2 This is an exploded perspective view of the battery according to Embodiment 1.

[0017] Figure 3 It is observed along the direction of the arrow on line III-III. Figure 1 A cross-sectional view of the battery.

[0018] Figure 4 It is observed along the direction of the arrow on line IV-IV. Figure 3 A cross-sectional view of the electrode body.

[0019] Figure 5 It is observed along the direction of the arrow on the VV line. Figure 3 A cross-sectional view of the electrode body.

[0020] Figure 6 It is a local observation along the direction of the arrow on line VI-VI. Figure 3 A schematic cross-sectional view of the electrode body.

[0021] Figure 7 This is the unfolded diagram of the first electrode.

[0022] Figure 8 It is an enlarged representation Figure 5 A partial cross-sectional view of region VIII of the first electrode. Detailed Implementation

[0023] The current collector and battery of one embodiment of the present disclosure will be described with reference to the accompanying drawings. It should be noted that in the drawings referred to below, the same or equivalent components are labeled with the same reference numerals.

[0024] Figure 1 This is a perspective view of the battery according to Embodiment 1. (e.g.) Figure 1 As shown, the battery 1 in Embodiment 1 is a so-called prismatic battery. Battery 1 can be a lithium-ion battery, nickel-metal hydride battery, or the like, configured as a rechargeable battery. Battery 1 can, for example, be used as a unit included in an energy storage module mounted in an electric vehicle.

[0025] Figure 2 This is an exploded perspective view of the battery according to Embodiment 1. Figure 3 It is observed along the direction of the arrow on line III-III. Figure 1 A cross-sectional view of the battery. (e.g.) Figures 1 to 3 As shown, a battery 1 according to one embodiment of this disclosure includes an electrode body 10, a housing 20, a first external terminal 30A, a second external terminal 30B, a first connecting portion 40A, a second connecting portion 40B, a first sealing ring 50A, a second sealing ring 50B, a first terminal support portion 60A, a second terminal support portion 60B, an insulating member 70, and a fuse protection portion 80. First, the structure of the battery 1 other than the electrode body 10 will be described.

[0026] The housing 20 is conductive. The conductive parts of the housing 20 are made of a metal such as aluminum. The housing 20 houses the electrode body 10. The housing 20 also houses an electrolyte (not shown).

[0027] The housing 20 includes a housing body 21 and a cover 22. The housing body 21 includes a bottom wall 21a and a peripheral wall 21b rising from the bottom wall 21a.

[0028] The bottom wall 21a includes a bottom body 21aa, a pressure relief valve 21ab, an outer protective membrane 21ac, and an inner protective membrane 21ad. The peripheral wall 21b rises from the bottom body 21aa. The pressure relief valve 21ab is disposed on the bottom body 21aa. The outer protective membrane 21ac covers the pressure relief valve 21ab from the outside. The inner protective membrane 21ad covers the pressure relief valve 21ab from the inside. The bottom body 21aa and the pressure relief valve 21ab are made of metal such as aluminum.

[0029] An opening is formed at the upper end of the peripheral wall 21b. The peripheral wall 21b has a generally rectangular shape when viewed from the opening direction. The opening and the bottom wall 21a are aligned along a first direction D1. The first direction D1 can also be the height direction of the battery 1 or the vertical direction. The peripheral wall 21b is made of a metal such as aluminum.

[0030] The cover 22 includes a cover body 22a, a sealing bolt 22b, a bolt cover 22c, and an insulating cover 22d.

[0031] The cover body 22a is joined to the peripheral wall 21b by welding or the like to close the opening of the peripheral wall 21b. A first connecting hole 22aa, a second connecting hole 22ab, and an electrolyte injection hole 22ac are formed in the cover body 22a. The electrolyte injection hole 22ac is a through hole used to inject electrolyte into the casing body 21 during the manufacturing process of the battery 1.

[0032] A sealing plug 22b seals the injection hole 22ac. A plug cover 22c covers the injection hole 22ac and the sealing plug 22b. An insulating cover 22d covers the injection hole 22ac, the sealing plug 22b, and the plug cover 22c.

[0033] The first external terminal 30A and the second external terminal 30B are provided in a manner that exposes them to the outside within the battery 1. The first connecting portion 40A and the second connecting portion 40B are conductive. At least a portion of the first connecting portion 40A and the second connecting portion 40B are disposed inside the housing 20.

[0034] The first external terminal 30A or the first connecting portion 40A passes through the first connecting hole 22aa. The first external terminal 30A and the first connecting portion 40A are electrically connected. Specifically, the first external terminal 30A and the first connecting portion 40A are engaged with each other. The first connecting portion 40A is engaged with the electrode body 10. Thus, the first external terminal 30A is electrically connected to the electrode body 10.

[0035] The second external terminal 30B or the second connecting portion 40B passes through the second connecting hole 22ab. The second external terminal 30B and the second connecting portion 40B are electrically connected. Specifically, the second external terminal 30B and the second connecting portion 40B are engaged with each other. The second connecting portion 40B is engaged with the electrode body 10. Thus, the second external terminal 30B is electrically connected to the electrode body 10.

[0036] It should be noted that in this embodiment, the first external terminal 30A is the positive terminal and the second external terminal 30B is the negative terminal. The first external terminal 30A and the second external terminal 30B are arranged in the second direction D2. The second direction D2 is a direction orthogonal to the first direction D1.

[0037] A first sealing ring 50A is disposed along the first connecting hole 22aa. The first sealing ring 50A is located in the gap between the cover body 22a and the first external terminal 30A, sealing this gap. A second sealing ring 50B is disposed along the second connecting hole 22ab. The second sealing ring 50B is located in the gap between the cover body 22a and the second external terminal 30B, sealing this gap. The first sealing ring 50A and the second sealing ring 50B are electrically insulating.

[0038] The first terminal support portion 60A is engaged with the cover body 22a. The first terminal support portion 60A supports the first external terminal 30A from its outer periphery. The first terminal support portion 60A includes a first locking ring 61A and a first covering ring 62A. The first locking ring 61A extends annularly around the first connecting hole 22aa and is directly engaged with the cover body 22a. The first covering ring 62A covers the first locking ring 61A. The first locking ring 61A supports the first external terminal 30A via the first covering ring 62A. The first covering ring 62A is made of a resin member having electrical insulation or relatively weak conductivity.

[0039] The second terminal support 60B is engaged with the cover body 22a. The second terminal support 60B supports the second external terminal 30B from its outer periphery. The second terminal support 60B includes a second locking ring 61B and a second covering ring 62B. The second locking ring 61B extends annularly around the second connecting hole 22ab and is directly engaged with the cover body 22a. The second covering ring 62B covers the second locking ring 61B. The second locking ring 61B supports the second external terminal 30B via the second covering ring 62B. The second covering ring 62B is made of an electrically insulating resin component.

[0040] The insulating member 70 is electrically insulating. The insulating member 70 is disposed between the electrode body 10 and the housing 20. The insulating member 70 electrically insulates the electrode body 10 and the housing 20 from each other. The insulating member 70 includes an insulating bracket 71, a peripheral insulating portion 72, a bottom insulating portion 73, and an insulating strip 74.

[0041] An insulating bracket 71 is disposed between the electrode body 10 and the cover body 22a. The insulating bracket 71 has high rigidity and is in contact with both the electrode body 10 and the cover body 22a. Thus, the electrode body 10 is fixed to the housing 20 in the first direction D1.

[0042] The peripheral insulating portion 72 is disposed between the electrode body 10 and the peripheral wall 21b. The peripheral insulating portion 72 is composed of a film-like component.

[0043] The bottom insulating portion 73 is disposed between the electrode body 10 and the bottom wall 21a. The bottom insulating portion 73 is composed of a film-like component.

[0044] Insulating tape 74 is bonded to both the peripheral insulating portion 72 and the bottom insulating portion 73. Insulating tape 74 fixes the peripheral insulating portion 72 and the bottom insulating portion 73 to each other.

[0045] like Figure 2 As shown, the battery 1 of this embodiment includes a plurality of electrode bodies 10. Typically, the battery 1 includes two electrode bodies 10. These electrode bodies 10 are arranged in a third direction D3. The third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2. It should be noted that the peripheral insulating portion 72 may also integrally cover the plurality of electrode bodies 10 in such a way that these electrode bodies 10 are fixed to each other.

[0046] The following description focuses on one of the plurality of electrode bodies 10. It should be noted that the plurality of electrode bodies 10 may also each have the structure shown below.

[0047] Figure 4 It is observed along the direction of the arrow on line IV-IV. Figure 3 A cross-sectional view of the electrode body. Figure 5 It is observed along the direction of the arrow on the VV line. Figure 3 A cross-sectional view of the electrode body. Figure 6 It is a local observation along the direction of the arrow on line VI-VI. Figure 3 A schematic cross-sectional view of the electrode body. (e.g.) Figures 2 to 6 As shown, the electrode body 10 includes a first electrode 11A, a second electrode 11B, and a spacer 12. The electrode body 10 is wound around a winding axis Z, with the first electrode 11A, the second electrode 11B, and the spacer 12. Thus, in this embodiment, the electrode body 10 is a so-called wound electrode body. However, the electrode body 10 could also be a stacked electrode body in which the first electrode 11A, the second electrode 11B, and the spacer 12 are stacked in one direction (e.g., a third direction D3). It should be noted that in... Figures 4 to 6 In the middle, the separator 12 is schematically represented by a dashed line.

[0048] The first electrode 11A and the second electrode 11B have a sheet-like shape. The electrode body 10 is composed of an electrode plate assembly formed by winding the first electrode 11A and the second electrode 11B with one or more separators 12 between them.

[0049] In this embodiment, the first electrode 11A is the positive electrode and the second electrode 11B is the negative electrode. However, it is also possible that the first electrode 11A is the negative electrode and the second electrode 11B is the positive electrode.

[0050] A separator 12 is disposed between the first electrode 11A and the second electrode 11B. The separator 12 allows ions to move between the first electrode 11A and the second electrode 11B, and separates the first electrode 11A from the second electrode 11B. The ions are, for example, lithium ions. The separator 12 is electrically insulating.

[0051] The first electrode 11A, the second electrode 11B, and the separator 12 are located at the innermost peripheral side with the winding axis Z as the center. Conversely, the first electrode 11A, the second electrode 11B, and the separator 12 are located at the outermost peripheral side with the winding axis Z as the center. The outer peripheral end edge of the separator 12 in the winding direction DR is fixed by a strip member 13 disposed on the outer peripheral surface of the separator 12.

[0052] The separator 12 may also comprise, for example, a polyolefin resin. The separator 12 may also be substantially composed of a polyolefin resin. The polyolefin resin may also comprise at least one selected from, for example, polyethylene (PE) and polypropylene (PP).

[0053] The first electrode 11A includes a first current collector 100A, a first active material layer 200A, and a protective part 300.

[0054] Figure 7 This is the unfolded diagram of the first electrode. That is, in Figure 7 The image shows the state of the first electrode 11A before it was wound. Figure 8 It is an enlarged representation Figure 5 A partial cross-sectional view of region VIII of the first electrode. (See attached image.) Figure 7 and Figure 8 As shown, the first current collector 100A includes a support portion 110 and a conductive portion 120.

[0055] The support portion 110 is made of an electrically insulating resin composition. Therefore, the first current collector 100A is a composite current collector composed of conductive and electrically insulating components. Furthermore, the support portion 110 is made of a material with higher rigidity than the separator 12. The support portion 110 is, for example, made of a resin composition comprising a polyamide-based resin, a polyester-based resin, or a polyolefin-based resin. To improve rigidity, the support portion 110 is preferably made of a resin composition comprising a polyester-based resin. More preferably, the support portion 110 is substantially made of a polyester-based resin. This polyester-based resin may, for example, be polyethylene terephthalate. This maintains the electrical insulation of the support portion 110 and improves the rigidity of the first current collector 100A. Furthermore, the support portion 110 can be made relatively thin.

[0056] The orthogonal direction DO, which is orthogonal to the thickness direction DT of the support portion 110, is approximately parallel to the first direction D1. That is, the support portion 110 extends approximately parallel to the first direction D1.

[0057] The support portion 110 has a support end edge 110e, a first support surface 111, and a second support surface 112. The support end edge 110e faces one side in a first direction D1. The support end edge 110e extends along the winding direction DR of the electrode body 10. The first support surface 111 is a surface facing one side in the thickness direction DT of the support portion 110. The second support surface 112 is a surface facing the other side in the thickness direction DT of the support portion 110.

[0058] To reduce the overall thickness of the electrode body 10, the thickness of the support portion 110 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The thickness of the support portion 110 is not particularly limited as long as it possesses the desired rigidity. For example, a thickness of 2 μm or more is acceptable.

[0059] like Figures 5 to 8 As shown, the conductive part 120 includes a first conductive layer 121, a second conductive layer 122, and a plurality of third conductive layers 123.

[0060] The first conductive layer 121 is disposed on the first support surface 111 of the support portion 110 (see reference). Figure 8 The first conductive layer 121 extends from the support portion 110. More specifically, the first conductive layer 121 extends in a manner that protrudes from the first support surface 111. The direction in which the first conductive layer 121 extends from the support portion 110, i.e., the extension direction DE, is the direction in which the support end edge 110e faces. The extension direction DE can be along the first direction D1 or along the orthogonal direction DO.

[0061] In this embodiment, the first conductive layer 121 is located on the Z side of the winding axis when viewed from the support portion 110. In addition, the first conductive layer 121 is in contact with the support portion 110 covering the entire surface of the first support surface 111.

[0062] A second conductive layer 122 is disposed on the second support surface 112 of the support portion 110. The second conductive layer 122 extends from the support portion 110. More specifically, the second conductive layer 122 extends in a manner that protrudes from the second support surface 112. The direction in which the second conductive layer 122 extends from the support portion 110 is the same as the direction in which the first conductive layer 121 extends from the support portion 110, i.e., the extension direction DE. The extension length of the second conductive layer 122 extending from the support portion 110 is substantially equal to the extension length of the first conductive layer 121 extending from the support portion 110, but they may also be different.

[0063] In this embodiment, the second conductive layer 122 is located on the side opposite to the Z-side of the winding axis when viewed from the support portion 110. Furthermore, the second conductive layer 122 is in contact with the support portion 110, covering the entire surface of the second support surface 112.

[0064] In addition, in this embodiment, the first conductive layer 121 has multiple extended portions (see reference). Figure 7 The second conductive layer 122 has multiple extensions. The multiple extensions of the first conductive layer 121 and the multiple extensions of the second conductive layer 122 are arranged in a one-to-one correspondence in the thickness direction DT.

[0065] Multiple third conductive layers 123 are disposed between the first conductive layer 121 and the second conductive layer 122 (see reference). Figure 7 and Figure 8 A plurality of third conductive layers 123 are bonded to both the first conductive layer 121 and the second conductive layer 122. The plurality of third conductive layers 123 extend between the first conductive layer 121 and the second conductive layer 122. The plurality of third conductive layers 123 are opposite to the support end edge 110e of the support portion 110. The plurality of third conductive layers 123 are separate from the support end edge 110e of the support portion 110. The plurality of third conductive layers 123 may also be connected to the support end edge 110e of the support portion 110.

[0066] It should be noted that the plurality of third conductive layers 123 and the plurality of extensions of the first conductive layer 121 are arranged in a one-to-one correspondence along the thickness direction DT (see reference). Figure 7 Multiple third conductive layers 123 and multiple extensions of the second conductive layer 122 are arranged in a one-to-one correspondence in the thickness direction DT. In addition, multiple third conductive layers 123 are bonded to the first conductive layer 121 and the second conductive layer 122, for example, by ultrasonic welding.

[0067] Multiple third conductive layers 123 are arranged such that they are aligned with each other in the third direction D3 (see reference). Figure 5 Multiple third conductive layers 123 are joined to each other, for example, by ultrasonic welding. Multiple third conductive layers 123 are joined to the first connecting portion 40A, for example, by ultrasonic welding (see reference). Figure 2 and Figure 3 ).

[0068] The thickness of the first conductive layer 121 is thinner than the thickness of the third conductive layer 123, and also thinner than the thickness of the support portion 110 (see reference). Figure 8The thickness of the second conductive layer 122 is thinner than the thickness of the third conductive layer 123, and also thinner than the thickness of the support portion 110. To make the overall thickness of the electrode body 10 thinner, the thicknesses of the first conductive layer 121 and the second conductive layer 122 are, for example, 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. To suppress excessive resistance in the first conductive layer 121 and the second conductive layer 122, the thicknesses of the first conductive layer 121 and the second conductive layer 122 are, for example, 0.1 μm or more. The thickness of the third conductive layer 123 is not particularly limited, but may be, for example, 20 μm or less, 15 μm or less, or 10 μm or less. The thickness of the third conductive layer 123 may also exceed 5 μm.

[0069] It should be noted that when the thickness of the first conductive layer 121 and the thickness of the second conductive layer 122 are less than 5 μm, it is difficult to directly weld the first conductive layer 121 and the second conductive layer 122 to each other or directly join them by ultrasonic welding. The thickness of the third conductive layer 123 is substantially equal to the thickness of the support portion 110.

[0070] The methods for forming the first conductive layer 121, the second conductive layer 122, and the third conductive layer 123 are not particularly limited. In this embodiment, the first conductive layer 121, the second conductive layer 122, and the third conductive layer 123 are typically made of a metal film. Thus, the first conductive layer 121 and the second conductive layer 122 are provided extending from the support portion 110. The metal film can typically be manufactured by compression molding. The first conductive layer 121 and the second conductive layer 122 can be bonded to the support portion 110 using an adhesive, or they can be pressed to the support portion 110 by mechanical rolling. Furthermore, the first conductive layer 121, the second conductive layer 122, and the third conductive layer 123 are typically made of a metal containing aluminum. Therefore, the first current collector 100A, which has the conductive portion 120, can be suitable for use as a positive current collector. It should be noted that the first current collector 100A can also be a negative current collector, and the first conductive layer 121, the second conductive layer 122 and the third conductive layer 123 can also be made of a metal containing copper.

[0071] A first active material layer 200A is stacked on a first conductive layer 121. The first active material layer 200A is a positive electrode active material layer, but it can also be a negative electrode active material layer. In this embodiment, the first active material layer 200A is further stacked on a second conductive layer 122. The first active material layer 200A includes a first inner active material layer 210A and a first outer active material layer 220A. The first inner active material layer 210A is stacked on the first conductive layer 121. The first outer active material layer 220A is stacked on the second conductive layer 122.

[0072] The first active material layer 200A has an active material end edge 200Ae. The active material end edge 200Ae faces the extension direction DE. The active material end edge 200Ae is arranged side by side with the support end edge 110e in the thickness direction DT of the support portion 110. More specifically, the active material end edge 200Ae of the first inner active material layer 210A is arranged side by side with the support end edge 110e in the thickness direction DT. The active material end edge 200Ae of the first outer active material layer 220 is arranged side by side with the support end edge 110e in the thickness direction DT.

[0073] It should be noted that the separator 12 is stacked on the first active material layer 200A (refer to) in the radial direction centered on the winding axis Z. Figure 5 (etc.). The separator 12 is stacked on the first inner active material layer 210A in the aforementioned radial direction. The separator 12 is also stacked on the first outer active material layer 220A in the aforementioned radial direction.

[0074] The protective portion 300 is electrically insulating, for example, made of ceramic. The protective portion 300 covers the upper part of the first active material layer 200A. The protective portion 300 covers the active material end edge 200Ae.

[0075] The protective portion 300 includes an inner protective portion 310 and an outer protective portion 320. The inner protective portion 310 covers the upper part of the first inner active material layer 210A. The outer protective portion 320 covers the upper part of the first outer active material layer 220A.

[0076] When viewed from the first conductive layer 121, the inner protective portion 310 is also provided on the first conductive layer 121 on the side opposite to the third conductive layer 123. Therefore, the protective portion 300 is not located on the conductive path from the first conductive layer 121 to the third conductive layer 123. Therefore, the resistance rise of the conductive portion 120 can be suppressed. Furthermore, when viewed from the second conductive layer 122, the outer protective portion 320 is also provided on the second conductive layer 122 on the side opposite to the third conductive layer 123. Therefore, the protective portion 300 is not located on the conductive path from the second conductive layer 122 to the third conductive layer 123. Therefore, the resistance rise of the conductive portion 120 can be suppressed.

[0077] like Figures 4 to 6 As shown, the second electrode 11B is stacked on the first active material layer 200A in the aforementioned radial direction, separated by the separator 12. More specifically, the second electrode 11B is stacked on the first inner active material layer 210A, separated by the separator 12, and also stacked on the first outer active material layer 220A, separated by the separator 12.

[0078] The second electrode 11B includes a second current collector 100B and a second active material layer 200B. The second current collector 100B includes a conductive support portion 140 and a plurality of tabs 150 (see reference). Figure 6 The conductive support portion 140 extends along the orthogonal direction DO (first direction D1). A plurality of tabs 150 extend from the upper end of the conductive support portion 140. The plurality of tabs 150 are joined together by ultrasonic welding, and are joined to the second connecting portion 40B (see reference). Figure 2 and Figure 3 ).

[0079] The plurality of tabs 150 and the conductive support portion 140 are constituted by an integral component, for example, by a metal film. In this embodiment, the plurality of tabs 150 and the conductive support portion 140 are constituted, for example, by a metal containing copper. Thus, the second current collector 100B can be adapted to be used as a negative current collector. It should be noted that when the first current collector 100A is a negative current collector and the second current collector 100B is a positive current collector, the plurality of tabs 150 and the conductive support portion 140 may also be constituted by a metal containing aluminum.

[0080] The second active material layer 200B is stacked on both sides of the conductive support portion 140 of the second current collector 100B. It should be noted that in this embodiment, the second electrode 11B is the negative electrode. Therefore, the second active material layer 200B is a negative electrode active material layer. It should also be noted that the second active material layer 200B can also be a positive electrode active material layer.

[0081] As described above, a first current collector 100A according to an embodiment of the present disclosure includes a support portion 110 and a conductive portion 120. The support portion 110 is made of a resin composition having electrical insulating properties. The conductive portion 120 includes a first conductive layer 121, a second conductive layer 122, and a third conductive layer 123. The first conductive layer 121 and the second conductive layer 122 extend from the support portion 110. The third conductive layer 123 is disposed between the first conductive layer 121 and the second conductive layer 122, bonded to both the first conductive layer 121 and the second conductive layer 122, and extends between the first conductive layer 121 and the second conductive layer 122.

[0082] According to the above structure, the third conductive layer 123 is disposed between the first conductive layer 121 and the second conductive layer 122 extending from the support portion 110, thus avoiding the third conductive layer 123 from overlapping with the support portion 110 in the thickness direction DT of the support portion 110. As a result, the thickness of the first current collector 100A is reduced. Furthermore, by bonding the third conductive layer 123 to the extending first conductive layer 121 and the second conductive layer 122, a larger bonding area with the first conductive layer 121 and the second conductive layer 122 can be ensured. This reduces the resistance of the conductive portion 120.

[0083] Furthermore, in this embodiment, the third conductive layer 123 is separated from the support portion 110. According to this structure, when the third conductive layer 123 is inclined relative to the direction in which it extends relative to the support portion 110, the first conductive layer 121 and the second conductive layer 122 can be easily bent between the third conductive layer 123 and the support portion 110. This prevents localized stress concentration in the first conductive layer 121 and the second conductive layer 122.

[0084] In addition, in this embodiment, the thickness of the third conductive layer 123 is substantially equal to the thickness of the support portion 110.

[0085] According to the above structure, bending of the first conductive layer 121 and the second conductive layer 122 between the support portion 110 and the third conductive layer 123 can be suppressed. Furthermore, the strength of the conductive portion 120 is improved.

[0086] Furthermore, in this embodiment, the thickness of the first conductive layer 121 is thinner than the thickness of the third conductive layer 123. The thickness of the second conductive layer 122 is thinner than the thickness of the third conductive layer 123.

[0087] According to the above structure, the bonding strength between the third conductive layer 123 and other components (typically the first connecting portion 40A) can be ensured, and the thickness of the first current collector 100A can be made thinner.

[0088] In this embodiment, the battery 1 of one embodiment of the present disclosure includes an electrode body 10, a first external terminal 30A, and a first connecting portion 40A. The electrode body 10 includes a first electrode 11A, a second electrode 11B, and a separator 12. The first electrode 11A includes a first current collector 100A and a first active material layer 200A. The first current collector 100A includes a support portion 110 and a conductive portion 120. The support portion 110 is made of a resin composition having electrical insulating properties. The conductive portion 120 includes a first conductive layer 121, a second conductive layer 122, and a third conductive layer 123. The first conductive layer 121 and the second conductive layer 122 extend from the support portion 110. The third conductive layer 123 is disposed between the first conductive layer 121 and the second conductive layer 122, bonded to both the first conductive layer 121 and the second conductive layer 122, and extends from between the first conductive layer 121 and the second conductive layer 122. A first active material layer 200A is stacked on a first conductive layer 121. A separator 12 is stacked on the first active material layer 200A. A second electrode 11B is stacked on the first active material layer 200A through the separator 12. A first external terminal 30A is electrically connected to a first connecting portion 40A. The first connecting portion 40A is bonded to a third conductive layer 123.

[0089] According to the above structure, the third conductive layer 123, which is bonded to the first connecting portion 40A, is disposed between the first conductive layer 121 and the second conductive layer 122 extending from the support portion 110, thus preventing the third conductive layer 123 from overlapping with the support portion 110 in the thickness direction DT. As a result, the thickness of the first current collector 100A is reduced. Therefore, by reducing the volume ratio of the first current collector 100A of the entire battery 1 and increasing the volume ratio of the first active material layer 200A, the energy density of the battery 1 can be improved. Furthermore, by bonding the third conductive layer 123 to the extending first conductive layer 121 and second conductive layer 122, the bonding area with the first conductive layer 121 and second conductive layer 122 can be ensured to be larger. This reduces the resistance of the conductive portion 120 and increases the first active material layer 200A, thereby improving the energy density of the battery 1.

[0090] In this embodiment, the support portion 110 has a support edge 110e. The support edge 110e faces the extending direction DE. The extending direction DE is the direction in which the first conductive layer 121 extends from the support portion 110. The first active material layer 200A has an active material edge 200Ae. The active material edge 200Ae faces the extending direction DE. The active material edge 200Ae is arranged side by side with the support edge 110e in the thickness direction DT of the support portion 110.

[0091] According to the above structure, the first active material layer 200A is firmly supported to the active material end edge 200Ae by the support portion 110 via the first conductive layer 121. Simultaneously, the first active material layer 200A can extend in the extension direction DE to a position parallel to the support end edge 110e. Furthermore, the energy density of the battery 1 can be improved.

[0092] It should be noted that during the process of the first active material layer 200A being disposed on the first conductive layer 121, the first active material layer 200A, together with the first conductive layer 121 and the support portion 110, is sometimes compressed in the thickness direction DT. In this case, according to the above structure, the portion near the active material end edge 200Ae in the first active material layer 200A can be compressed more reliably together with the support portion 110.

[0093] In the description of the above embodiments, the structures that can be combined can also be combined with each other.

[0094] Embodiments of the present invention have been described, but should be considered as illustrative rather than restrictive in all respects. The scope of the invention is defined by the claims and is intended to include all modifications equivalent to or within the scope of the claims.

Claims

1. A current collector, wherein, This current collector has the following features: Support; and Conductive part, The support portion is made of an electrically insulating resin composition. The conductive portion includes a first conductive layer, a second conductive layer, and a third conductive layer. The first conductive layer and the second conductive layer extend from the support portion. The third conductive layer is disposed between the first conductive layer and the second conductive layer, bonded to both the first conductive layer and the second conductive layer, and extends from between the first conductive layer and the second conductive layer.

2. The current collector according to claim 1, wherein, The third conductive layer is separated from the support portion.

3. The current collector according to claim 1, wherein, The thickness of the third conductive layer is substantially equal to the thickness of the support portion.

4. The current collector according to any one of claims 1 to 3, wherein, The thickness of the first conductive layer is thinner than the thickness of the third conductive layer. The thickness of the second conductive layer is thinner than the thickness of the third conductive layer.

5. A battery, wherein, This battery has the following features: Electrode body; External terminals; and Connector 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 portion and a conductive portion. The support portion is made of an electrically insulating resin composition. The conductive portion includes a first conductive layer, a second conductive layer, and a third conductive layer. The first conductive layer and the second conductive layer extend from the support portion. The third conductive layer is disposed between the first conductive layer and the second conductive layer, bonded to both the first and second conductive layers, and extends from between the first and second conductive layers. The active material layer is stacked on the first conductive layer. The separator is stacked on top of the active material layer. The second electrode is stacked on the active material layer with the separator in between. The external terminal is electrically connected to the connecting part. The connecting portion is bonded to the third conductive layer.

6. The battery according to claim 5, wherein, The third conductive layer is separated from the support portion.

7. The battery according to claim 5, wherein, The thickness of the third conductive layer is substantially equal to the thickness of the support portion.

8. The battery according to any one of claims 5 to 7, wherein, The thickness of the first conductive layer is thinner than the thickness of the third conductive layer. The thickness of the second conductive layer is thinner than the thickness of the third conductive layer.

9. The battery according to any one of claims 5 to 7, wherein, The support portion has a support end edge extending from the support portion toward the first conductive layer, i.e., the extension direction. The active material layer has active material end edges facing the extension direction. The active material edge is arranged side by side with the support edge in the thickness direction of the support portion.

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