Current collector and battery

Abstract

The invention relates to a current collector and a battery. The current collector includes an insulating support layer, a conductive support layer, a first conductive layer, and a tab portion. The insulating support layer is configured from a resin composition having electrical insulating properties. The conductive support layer is adjacent to the insulating support layer. The first conductive layer is laminated on both the insulating support layer and the conductive support layer. The tab portion is arranged in parallel with the conductive support layer with the first conductive layer interposed therebetween, and is bonded to the first conductive layer by ultrasonic bonding.

Description

Technical Field

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

[0002] An electrode plate is disclosed in Japanese Patent Application Publication No. 2024-510696. The electrode plate includes a current collector and an electrical connection member. The electrical connection member is electrically connected to the current collector. 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 the relay weld area. The current collector includes a support layer and a conductive layer. The conductive layer is disposed on one surface of the support layer. The support layer uses an organic polymer material or a polymer composite material. Summary of the Invention

[0003] When the conductive layer and the electrical connection member (ear portion) are welded together, there is a possibility that the insulating support layer melts, and a portion of the support layer becomes mixed into the weld joint area. In this case, the resistance in the weld joint area increases. Consequently, when current flows between the conductive layer and the electrical connection member, the weld joint area heats up. Furthermore, in the above-described situation, the bonding strength between the conductive layer and the electrical connection member in the weld joint area decreases.

[0004] This disclosure was made in view of the above-mentioned problems, and its object is to provide a current collector that reduces heat generation at the junction of the conductive layer and the tab and increases the bonding strength of the junction, and a battery having the current collector.

[0005] According to one aspect of this disclosure, a current collector includes an insulating support layer, a conductive support layer, a first conductive layer, and a tab. The insulating support layer is composed of a resin composition having electrical insulating properties. The conductive support layer is adjacent to the insulating support layer. The first conductive layer is laminated between the insulating support layer and the conductive support layer. The tab is arranged side-by-side with the conductive support layer across the first conductive layer and is bonded to the first conductive layer by ultrasonic bonding.

[0006] A battery according to one aspect of this disclosure includes an electrode body and external terminals. The electrode body includes a first electrode, a second electrode, and a separator. The first electrode includes a current collector and a one-sided active material layer. The current collector includes an insulating support layer, a conductive support layer, a first conductive layer, and a tab. The insulating support layer is composed of a resin composition having electrical insulating properties. The conductive support layer is adjacent to the insulating support layer. The first conductive layer is laminated between the insulating support layer and the conductive support layer. The tab is arranged side-by-side with the conductive support layer across the first conductive layer and is bonded to the first conductive layer by ultrasonic bonding. The one-sided active material layer is laminated between the first conductive layer. The separator is laminated between the one-sided active material layer. The second electrode is laminated between the separator and the one-sided active material layer. The external terminals are electrically connected to the tabs.

[0007] According to this disclosure, it is possible to reduce the heat generation at the junction of the conductive layer and the tab, and to improve the bonding strength of the junction. Attached Figure Description

[0008] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and wherein:

[0009] Figure 1 This is a cross-sectional view showing one embodiment of a battery.

[0010] Figure 2 It is observed along the direction of the arrow on line II-II. Figure 1 A cross-sectional view of the electrode body.

[0011] Figure 3 It is observed along the direction of the arrow on line III-III. Figure 1 A cross-sectional view of the electrode body.

[0012] Figure 4 It is a local observation along the direction of the arrow on line IV-IV. Figure 1 A schematic cross-sectional view of the electrode body.

[0013] Figure 5 This is the unfolded diagram of the first electrode.

[0014] Figure 6 It is an enlarged representation Figure 3 A partial cross-sectional view of region VI of the first electrode. Detailed Implementation

[0015] 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.

[0016] Figure 1 This is a cross-sectional view showing one embodiment of a battery. Figure 1 The battery 1 shown is a so-called square battery. Battery 1 can 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 battery cell included in an energy storage module mounted in an electric vehicle.

[0017] like Figure 1 As shown, a battery 1 according to one embodiment of the present disclosure includes an electrode body 10, a housing 20, a first external terminal 30A, a second external terminal 30B, a first connecting member 40A, and a second connecting member 40B. First, the structure of the battery 1 excluding the electrode body 10 will be described.

[0018] 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).

[0019] 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.

[0020] The cover 22 is joined to the peripheral wall 21b by welding or the like to close the opening of the peripheral wall 21b. The cover 22 has a first connecting hole 22a and a second connecting hole 22b.

[0021] The first external terminal 30A and the second external terminal 30B are arranged in such a way that they are 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 disposed inside the housing 20.

[0022] The first external terminal 30A or the first connecting member 40A passes through 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 engaged with each other. The first connecting member 40A is engaged with the electrode body 10. Thus, the first external terminal 30A is electrically connected to the electrode body 10.

[0023] The second external terminal 30B or the second connecting member 40B passes through 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 engaged with each other. The second connecting member 40B is engaged with the electrode body 10. Thus, the second external terminal 30B is electrically connected to the electrode body 10.

[0024] 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 side by side in the second direction D2. The second direction D2 is a direction orthogonal to the first direction D1.

[0025] Next, the electrode bodies 10 will be described. 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 side by side in a third direction D3. The third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2.

[0026] 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.

[0027] Figure 2It is observed along the direction of the arrow on line II-II. Figure 1 A cross-sectional view of the electrode body. Figure 3 It is observed along the direction of the arrow on line III-III. Figure 1 A cross-sectional view of the electrode body. Figure 4 It is a local observation along the direction of the arrow on line IV-IV. Figure 1 A schematic cross-sectional view of the electrode body. (See example...) Figures 1 to 4 As shown, the electrode body 10 includes a first electrode 11A, a second electrode 11B, and a spacer 12. In the electrode body 10, the first electrode 11A, the second electrode 11B, and the spacer 12 are wound around 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 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... Figures 2 to 4 In the middle, the separator 12 is schematically represented by a dashed line.

[0028] 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 spacers 12 between them.

[0029] 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.

[0030] A separator 12 is disposed between the first electrode 11A and the second electrode 11B. The separator 12 allows ions to travel back and forth between the first electrode 11A and the second electrode 11B, and separates the first electrode 11A and the second electrode 11B. The ions are, for example, lithium ions. The separator 12 is electrically insulating.

[0031] The first electrode 11A, the second electrode 11B, and the separator 12 are located on the innermost circumference with the winding axis Z as the center. The separator 12 is located on the outermost circumference with the winding axis Z as the center. The outer circumferential edge of the separator 12 in the winding direction DR is fixed by a strip member 13 disposed on the outer circumferential surface of the separator 12.

[0032] The separator 12 may, for example, comprise a polyolefin resin. The separator 12 may also be substantially composed of a polyolefin resin. The polyolefin resin may, for example, comprise at least one selected from the group consisting of polyethylene (PE) and polypropylene (PP).

[0033] Figure 5 This is the unfolded diagram of the first electrode. That is, in Figure 5 The image shows the state of the first electrode 11A before it is wound. Figure 6 It is an enlarged representation Figure 3 A partial cross-sectional view of region VI of the first electrode. (See attached image.) Figures 3 to 6 As shown, the first electrode 11A includes a current collector 100A, an active material layer 200A on one side, an active material layer 300A on the other side, a first protection part 400, and a second protection part 500.

[0034] The first current collector 100A includes an insulating support layer 110, multiple conductive support layers 120, a first conductive layer 130, multiple tabs 140, a second conductive layer 150, and multiple bonding aids 160.

[0035] The insulating support layer 110 is made of a resin composition with electrical insulating properties. Therefore, the first current collector 100A is a composite current collector made of conductive and electrically insulating components. As a result, compared to the case where the first current collector 100A is made entirely of metal, the first current collector 100A is lighter, and the safety of the battery 1 as a whole is improved.

[0036] The insulating support layer 110 is, for example, composed of a resin composition comprising a polyamide resin, a polyester resin, or a polyolefin resin. To improve rigidity, the insulating support layer 110 is preferably composed of a resin composition comprising a polyester resin. More preferably, the insulating support layer 110 is substantially composed of a polyester resin. This polyester resin may, for example, be polyethylene terephthalate. This allows the electrical insulation of the insulating support layer 110 to be maintained and improves the rigidity of the first current collector 100A. Furthermore, the insulating support layer 110 can be made relatively thin.

[0037] The orthogonal direction DO, which is orthogonal to the thickness direction DT of the insulating support layer 110, is approximately parallel to the first direction D1. That is, the insulating support layer 110 extends approximately parallel to the first direction D1.

[0038] The insulating support layer 110 includes an end face 111, a first surface 112, and a second surface 113. The end face 111 faces one side of the orthogonal direction DO (first direction D1). The first surface 112 is a surface facing one side of the thickness direction DT of the insulating support layer 110. The second surface 113 is a surface facing the other side of the thickness direction DT of the insulating support layer 110.

[0039] To reduce the overall thickness of the electrode body 10, the thickness of the insulating support layer 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 insulating support layer 110 is not particularly limited as long as it possesses the desired rigidity. For example, a thickness of 2 μm or more is acceptable.

[0040] like Figure 5 As shown, multiple conductive support layers 120 are arranged side-by-side in the winding direction DR of the electrode body 10. The multiple conductive support layers 120 are separated from each other. The structure of each of the multiple conductive support layers 120 will be described below.

[0041] like Figure 6 As shown, the conductive support layer 120 is adjacent to the insulating support layer 110. More specifically, the conductive support layer 120 and the insulating support layer 110 are adjacent in the orthogonal direction DO (first direction D1). The thickness direction of the conductive support layer 120 is the same as the thickness direction DT of the insulating support layer 110. The conductive support layer 120 is in contact with the end face 111.

[0042] The conductive support layer 120 is conductive. The material constituting the conductive support layer 120 is not particularly limited. It can be a metal such as aluminum or copper, or a conductive resin. The conductive resin can also become conductive by containing fillers with high conductivity, such as carbon or metals.

[0043] The thickness of the conductive support layer 120 is not particularly limited, but it is preferably substantially equal to that of the insulating support layer 110. Thus, the first conductive layer 130 and the second conductive layer 150, described later, can extend substantially parallel and uniformly in the orthogonal direction DO (first direction D1). The thickness of the conductive support layer 120 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. For example, the thickness of the conductive support layer 120 can be 2 μm or more.

[0044] A first conductive layer 130 is stacked on both the insulating support layer 110 and the conductive support layer 120. The first conductive layer 130 is disposed on a first surface 112 of the insulating support layer 110. The first conductive layer 130 extends from the insulating support layer 110 at multiple locations. More specifically, the first conductive layer 130 extends from the first surface 112. The direction in which the first conductive layer 130 extends from the insulating support layer 110, i.e., the extension direction DE, is the direction in which the end face 111 faces. The extension direction DE can be along a first direction D1 or along an orthogonal direction DO. Multiple conductive support layers 120 are stacked on each of the multiple extensions of the first conductive layer 130.

[0045] In this embodiment, the first conductive layer 130 is located on one side of the winding axis Z when viewed from the insulating support layer 110. However, the first conductive layer 130 may also be located on the side opposite to the winding axis Z when viewed from the insulating support layer 110.

[0046] like Figure 5As shown, a plurality of tabs 140 are arranged side by side in the winding direction DR of the electrode body 10. The plurality of tabs 140 are separated from each other. The plurality of tabs 140 are arranged side by side in the thickness direction DT in a one-to-one correspondence with a plurality of conductive support layers 120.

[0047] like Figure 3 As shown, multiple tabs 140 are joined together by means of ultrasonic bonding or the like. Furthermore, as... Figure 1 As shown, the plurality of tabs 140 are also connected to the first connecting member 40A via ultrasonic bonding or the like. Thus, the first external terminal 30A is electrically connected to the tabs 140. The structure of each of the plurality of tabs 140 will be described below.

[0048] like Figure 6 As shown, the tab 140 is arranged side-by-side with the conductive support layer 120, separated by the first conductive layer 130. The tab 140 is bonded to the first conductive layer 130 by ultrasonic bonding. Figure 6 The diagram shows a first bonding portion J1, which serves as the bonding portion between the first conductive layer 130 and the tab 140. The tab 140 extends from the first conductive layer 130 in the extending direction DE. The end edge of the tab 140 on the side opposite to the extending direction DE is arranged side by side with the end face 111 in the thickness direction DT.

[0049] The second conductive layer 150 is located opposite to the first conductive layer 130 when viewed from the conductive support layer 120. The second conductive layer 150 is disposed on the second surface 113 of the insulating support layer 110. The second conductive layer 150 is stacked on both the insulating support layer 110 and the conductive support layer 120. The second conductive layer 150 extends from the insulating support layer 110 at multiple locations. More specifically, the second conductive layer 150 extends from the second surface 113. The direction in which the second conductive layer 150 extends from the insulating support layer 110 is the same as the direction in which the first conductive layer 130 extends from the insulating support layer 110, i.e., the extension direction DE. The extension length of the second conductive layer 150 extending from the insulating support layer 110 is substantially equal to the extension length of the first conductive layer 130 extending from the insulating support layer 110. Multiple conductive support layers 120 are stacked on each of these extended portions of the second conductive layer 150.

[0050] like Figure 5As shown, a plurality of bonding aids 160 are arranged side-by-side in the winding direction DR of the electrode body 10. The plurality of bonding aids 160 are separated from each other. The plurality of bonding aids 160 are arranged side-by-side in the thickness direction DT in a one-to-one correspondence with a plurality of conductive support layers 120. Viewed from the thickness direction DT, each of the plurality of bonding aids 160 has the same shape as the conductive support layers 120 arranged side-by-side in the thickness direction DT. The structure of the plurality of bonding aids 160 will be described below.

[0051] like Figure 6 As shown, the bonding auxiliary portion 160 is arranged side-by-side with the tab portion 140, separated by the second conductive layer 150, the conductive support layer 120, and the first conductive layer 130. The bonding auxiliary portion 160 is bonded to the second conductive layer 150 by ultrasonic bonding. Figure 6 The diagram shows the second joining portion J2, which serves as the joining portion between the second conductive layer 150 and the joining auxiliary portion 160. The end edge of the joining auxiliary portion 160 facing the extension direction DE is arranged side-by-side with the end edges of the conductive support layer 120, the first conductive layer 130, and the second conductive layer 150 facing the extension direction DE in the thickness direction DT. The end edge of the joining auxiliary portion 160 facing a direction opposite to the extension direction DE is arranged side-by-side with the end face 111 in the thickness direction DT.

[0052] The thickness of the first conductive layer 130 is thinner than the thickness of the conductive support layer 120 and thinner than the thickness of the insulating support layer 110. The thickness of the second conductive layer 150 is thinner than the thickness of the conductive support layer 120 and thinner than the thickness of the insulating support layer 110. In order to make the overall thickness of the electrode body 10 thinner, the thickness of the first conductive layer 130 and the thickness of the second conductive layer 150 are, for example, 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. In order to suppress the resistance of the first conductive layer 130 and the second conductive layer 150 from becoming too high, the thickness of the first conductive layer 130 and the second conductive layer 150 is, for example, 0.1 μm or more. It should be noted that when the thickness of the first conductive layer 130 and the second conductive layer 150 is 5 μm or less, it is difficult to directly weld the first conductive layer 130 and the second conductive layer 150 together or directly join them together by ultrasonic welding.

[0053] The thickness of the tab portion 140 and the bonding aid portion 160 is not particularly limited as long as it is sufficient for ultrasonic bonding. The thickness of the tab portion 140 and the bonding aid portion 160 is thicker than the thickness of the first conductive layer 130 and thicker than the thickness of the second conductive layer 150. The thickness of the tab portion 140 and the bonding aid portion 160 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The thickness of the tab portion 140 and the bonding aid portion 160 is not particularly limited as long as they possess the desired rigidity. For example, the thickness of the tab portion 140 and the bonding aid portion 160 can be 2 μm or more.

[0054] The method for forming the first conductive layer 130 and the second conductive layer 150 is not particularly limited. In this embodiment, typically, the first conductive layer 130 and the second conductive layer 150 are made of a metal film. Therefore, the first conductive layer 130 and the second conductive layer 150 can be easily laminated onto both the insulating support layer 110 and the conductive support layer 120. Typically, the metal film can also be manufactured by extrusion. The first conductive layer 130 and the second conductive layer 150 can be bonded to the insulating support layer 110 and the conductive support layer 120 using an adhesive, or they can be pressed onto the insulating support layer 110 and the conductive support layer 120 using mechanical rolling. Furthermore, typically, the first conductive layer 130 and the second conductive layer 150 are made of a metal containing aluminum. Therefore, the first current collector 100A, equipped with the first conductive layer 130 and the second conductive layer 150, is 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 130 and the second conductive layer 150 can also be made of a metal containing copper.

[0055] The materials constituting the tab portion 140 and the engagement aid portion 160 are not particularly limited, but in this embodiment, the engagement aid portion 160 is made of the same material as the tab portion 140. The tab portion 140 and the engagement aid portion 160 are, for example, made of a metal film, typically made of a metal containing aluminum or copper.

[0056] One side of the active material layer 200A is stacked on the first conductive layer 130. The other side of the active material layer 300A is stacked on the second conductive layer 150. Both the one side of the active material layer 200A and the other side of the active material layer 300A are positive electrode active material layers, but they can also be negative electrode active material layers. The one side of the active material layer 200A is separated from the tab portion 140. The other side of the active material layer 300A is separated from the bonding auxiliary portion 160.

[0057] It should be noted that the separator 12 is stacked radially on one side of the active material layer 200A (refer to) with the winding axis Z as the center. Figure 3(etc.). In addition, the separator 12 is also stacked on the other side of the active material layer 300A in the aforementioned radial direction.

[0058] The first protective portion 400 is made of electrically insulating ceramic. The first protective portion 400 covers a portion of the extension direction DE side of one side of the active material layer 200A. The first protective portion 400 covers the entire surface of the first conductive layer 130 between one side of the active material layer 200A and the tab portion 140. It should be noted that the first protective portion 400 is not disposed between the first conductive layer 130 and the tab portion 140.

[0059] The second protective portion 500 is made of electrically insulating ceramic. The second protective portion 500 covers a portion of the DE-side of the active material layer 300A on the other side. The second protective portion 500 covers the entire surface of the second conductive layer 150 between the active material layer 300A on the other side and the bonding auxiliary portion 160. It should be noted that the second protective portion 500 is not disposed between the second conductive layer 150 and the bonding auxiliary portion 160.

[0060] like Figures 2 to 4 As shown, the second electrode 11B is stacked on one side of the active material layer 200A in the aforementioned radial direction, separated by the separator 12. The second electrode 11B is also stacked on the other side of the active material layer 300A, separated by the separator 12. In this embodiment, the electrode body 10 includes multiple separators 12, but it may also include a single separator 12.

[0061] 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 170 and a plurality of second electrode tabs 180 (see reference). Figure 4 The conductive support portion 170 extends along the orthogonal direction DO (first direction D1). A plurality of second electrode tabs 180 extend from the upper end of the conductive support portion 170. The plurality of second electrode tabs 180 are joined together by ultrasonic welding and are engaged with the second connecting member 40B (see reference). Figure 1 ).

[0062] The plurality of second electrode tabs 180 and conductive support portions 170 are constituted by an integral component, for example, by a metal film. In this embodiment, the plurality of second electrode tabs 180 and conductive support portions 170 are constituted, for example, by a metal containing copper. Thus, the second current collector 100B can be suitable for use 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 second electrode tabs 180 and conductive support portions 170 may also be constituted by a metal containing aluminum.

[0063] The second active material layer 200B is stacked on both sides of the conductive support portion 170 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.

[0064] As described above, in a battery 1 according to one embodiment of this disclosure, the current collector 100A includes an insulating support layer 110, a conductive support layer 120, a first conductive layer 130, and a tab 140. The insulating support layer 110 is made of a resin composition having electrical insulating properties. The conductive support layer 120 is adjacent to the insulating support layer 110. The first conductive layer 130 is stacked on both the insulating support layer 110 and the conductive support layer 120. The tab 140 is arranged side by side with the conductive support layer 120 across the first conductive layer 130 and is bonded to the first conductive layer 130 by ultrasonic bonding.

[0065] As described above, when the tab 140 and the first conductive layer 130 are joined together by ultrasonic welding, sometimes a conductive support layer 120 is mixed in at the first joint portion J1, which is the joint portion of the first conductive layer 130 and the tab 140. Therefore, in the first joint portion J1, the tab 140 and the first conductive layer 130 are sometimes not uniformly joined. However, since the conductive support layer is conductive, even if the tab 140 and the first conductive layer 130 are not uniformly joined, the situation that hinders the conductivity of the first joint portion J1 is suppressed. Therefore, according to the above structure, the heat generation at the joint portion J1 of the first conductive layer 130 and the tab 140 is reduced. Furthermore, by using a material with a higher melting point than the insulating support layer 110 to form the conductive support layer 120, melting of the conductive support layer 120 can be suppressed. Therefore, the joint between the first conductive layer 130 and the tab 140 in the first joint portion J1 becomes more uniform. Therefore, according to the above structure, the bonding strength of the first joint portion J1 can be improved.

[0066] Furthermore, the current collector 100A according to one embodiment of this disclosure also includes a second conductive layer 150 and a bonding auxiliary portion 160. The second conductive layer 150 is stacked on both the insulating support layer 110 and the conductive support layer 120, and is located opposite to the first conductive layer 130 when viewed from the conductive support layer 120. The bonding auxiliary portion 160 is made of the same material as the tab portion 140. The bonding auxiliary portion 160 is arranged side by side with the tab portion 140, separated by the second conductive layer 150, the conductive support layer 120, and the first conductive layer 130, and is bonded to the second conductive layer 150 by ultrasonic bonding.

[0067] According to the above structure, by forming a second joint portion J2, which is an ultrasonically bonded joint portion of the first joint portion J1 and the second conductive layer 150, simultaneously with the first joint portion J1, it is possible to improve the uniformity of the joint between the first joint portion J1 and the second joint portion J2 at a lower cost. Furthermore, in the conductive path from the second conductive layer 150 to the tab portion 140, heat generation in the second joint portion J2 and the first joint portion J1 can be reduced. It should be noted that the first joint portion J1 and the second joint portion J2 can be formed, for example, by sandwiching the conductive support layer 120, the first conductive layer 130, the tab portion 140, the second conductive layer 150, and the joint auxiliary portion 160 in a region R where they are stacked, using a welding head and anvil (neither shown) for ultrasonic bonding.

[0068] Furthermore, in a battery 1 according to one embodiment of this disclosure, the first electrode 11A further includes a first protective portion 400 and a second protective portion 500. The first protective portion 400 is made of electrically insulating ceramic. The first protective portion 400 covers a portion of one side of the active material layer 200A, covers the entire surface of the first conductive layer 130 between the one side of the active material layer 200A and the tab portion 140, and is not disposed between the first conductive layer 130 and the tab portion 140. The second protective portion 500 is made of electrically insulating ceramic. The second protective portion 500 covers a portion of the other side of the active material layer 300A, covers the entire surface of the second conductive layer 150 between the other side of the active material layer 300A and the bonding auxiliary portion 160, and is not disposed between the second conductive layer 150 and the bonding auxiliary portion 160.

[0069] According to the above structure, the first protective portion 400 can prevent metallic foreign matter generated due to the bonding of the tab 140 with other components from contacting the first conductive layer 130 or one side of the active material layer 200A. Furthermore, since the first protective portion 400 is not disposed between the first conductive layer 130 and the tab 140, the first conductive layer 130 and the tab 140 can be tightly sealed when the first bonding portion J1 is formed. This further prevents a decrease in the bonding strength of the first bonding portion J1. Furthermore, the second protective portion 500 can prevent metallic foreign matter generated due to the bonding of the tab 140 with other components from contacting the second conductive layer 150 or the other side of the active material layer 300A. Furthermore, since the second protective portion 500 is not disposed between the second conductive layer 150 and the bonding aid portion 160, the first conductive layer 130 and the tab 140 can be tightly sealed when the first bonding portion J1 is formed together with the second bonding portion J2. Therefore, it is possible to suppress the decrease in the bonding strength of the second bonding portion J2.

[0070] In the description of the above embodiments, the structures that can be combined can also be combined with each other.

[0071] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this disclosure is defined not by the foregoing description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A current collector, wherein, This current collector has the following features: Insulating support layer; Conductive support layer; The first conductive layer; and extreme ear area, The insulating support layer is composed of an electrically insulating resin composition. The conductive support layer is adjacent to the insulating support layer. The first conductive layer is stacked on both the insulating support layer and the conductive support layer. The tab portion is arranged side by side with the conductive support layer through the first conductive layer, and is bonded to the first conductive layer by ultrasonic bonding.

2. The current collector according to claim 1, wherein The current collector also has: The second conductive layer; and Joining auxiliary part, The second conductive layer is stacked on top of both the insulating support layer and the conductive support layer, and is located opposite to the first conductive layer when viewed from the conductive support layer. The engagement auxiliary portion is made of the same material as the material constituting the tab portion. The bonding auxiliary portion is arranged side by side with the tab portion, separated by the second conductive layer, the conductive support layer and the first conductive layer, and is bonded to the second conductive layer by ultrasonic bonding.

3. A battery, wherein, This battery has the following features: Electrode body; and external terminals, 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 on one side. The current collector includes an insulating support layer, a conductive support layer, a first conductive layer, and a tab portion. The insulating support layer is composed of an electrically insulating resin composition. The conductive support layer is adjacent to the insulating support layer. The first conductive layer is stacked on both the insulating support layer and the conductive support layer. The tabs are arranged side-by-side with the conductive support layer, separated by the first conductive layer, and are bonded to the first conductive layer by ultrasonic bonding. The active material layer on one side is stacked on the first conductive layer. The separator is stacked on the active material layer on one side. The second electrode is stacked on one side of the active material layer, separated by the separator. The external terminal is electrically connected to the electrode portion.

4. The battery according to claim 3, wherein, The first electrode also includes an active material layer on the other side. The current collector also includes a second conductive layer and a bonding auxiliary portion. The second conductive layer is stacked on top of both the insulating support layer and the conductive support layer, and is located opposite to the first conductive layer when viewed from the conductive support layer. The engagement auxiliary portion is made of the same material as the material constituting the tab portion. The bonding auxiliary portion is arranged side-by-side with the tab portion, separated by the second conductive layer, the conductive support layer, and the first conductive layer, and is bonded to the second conductive layer by ultrasonic bonding. The active material layer on the other side is stacked on the second conductive layer. The separator is also stacked on the other side of the active material layer. The second electrode is also stacked on the other side of the active material layer, separated by the separator.

5. The battery according to claim 4, wherein, The first electrode further includes a first protective part and a second protective part. The first protective part is made of electrically insulating ceramic. The first protective portion covers a portion of the active material layer on one side, covers the entire surface of the first conductive layer between the active material layer on one side and the tab, and is not disposed between the first conductive layer and the tab. The second protective part is made of electrically insulating ceramic. The second protective portion covers a portion of the active material layer on the other side, covers the entire surface of the second conductive layer between the active material layer on the other side and the bonding auxiliary portion, and is not disposed between the second conductive layer and the bonding auxiliary portion.

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