Current collector and battery

Abstract

This reduces heat generation at the joint between the conductive layer and the tab portion, and improves the bonding strength of the joint. [Solution] The current collector 100A comprises an insulating support layer 110, a conductive support layer 120, a first conductive layer 130, and a tab portion 140. The insulating support layer 110 is made of an electrically insulating resin composition. The conductive support layer 120 is adjacent to the insulating support layer 110. The first conductive layer 130 is laminated on both the insulating support layer 110 and the conductive support layer 120. The tab portion 140 is aligned with the conductive support layer 120 via the first conductive layer 130 and is joined to the first conductive layer 130 by ultrasonic bonding.

Description

Technical Field

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

Background Art

[0002] JP-T-2024-510696 discloses an electrode plate. 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 and connected at the edge of the current collector. The welded connection region is called an intermediate welding region. The current collector includes a support layer and a conductive layer. The conductive layer is provided on one surface of the support layer. An organic polymer material or a polymer composite material is used for the support layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the conductive layer and the electrical connection member (tab portion) are welded to each other, the insulating support layer may melt and a part of the support layer may mix into the welded connection region. In this case, the electrical resistance in the welded connection region increases. As a result, when an electric current flows between the conductive layer and the electrical connection member, the welded connection region generates heat. Also, in the above case, in the welded connection region, the bonding strength between the conductivity and the electrical connection member decreases.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a current collector and a battery including the same, in which heat generation at the joint portion between the conductive layer and the tab portion is reduced and the joint strength of the joint portion is improved.

Means for Solving the Problems

[0006] A current collector according to a certain aspect of the present disclosure comprises an insulating support layer, a conductive support layer, a first conductive layer, and a tab portion. The insulating support layer is made of an electrically insulating resin composition. 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 adjacent to the conductive support layer via the first conductive layer and is joined to the first conductive layer by ultrasonic bonding.

[0007] A battery according to a certain aspect of this disclosure comprises an electrode body and an external terminal. The electrode body includes a first electrode, a second electrode, and a separator. The first electrode includes a current collector and 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 portion. The insulating support layer is made of an electrically insulating resin composition. 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 adjacent to the conductive support layer via the first conductive layer and is bonded to the first conductive layer by ultrasonic bonding. The one-sided active material layer is laminated on the first conductive layer. The separator is laminated on the one-sided active material layer. The second electrode is laminated on the one-sided active material layer via the separator. The external terminal is electrically connected to the tab portion. [Effects of the Invention]

[0008] According to this disclosure, heat generation at the joint between the conductive layer and the tab portion can be reduced, and the bonding strength of the joint can be improved. [Brief explanation of the drawing]

[0009] [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 a cross-sectional view of the electrode body in Figure 1, taken in the direction of the arrow III-III. [Figure 4] This is a schematic cross-sectional view of the electrode body in Figure 1, partially viewed in the direction of the IV-IV arrow. [Figure 5]This is a diagram of the first electrode. [Figure 6] This is a partial cross-sectional view showing an enlarged view of region VI of the first electrode in Figure 3. [Modes for carrying out the invention]

[0010] A current collector and a battery according to one embodiment of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same numbers.

[0011] 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.

[0012] 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.

[0013] Case 20 is conductive. The conductive portion of Case 20 is made of a metal such as aluminum. Case 20 houses the electrode body 10. Case 20 also houses an electrolyte (not shown).

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

[0015] The lid 22 is joined to the peripheral wall 21b by welding or 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.

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

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

[0018] 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.

[0019] 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.

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

[0021] In the following, one electrode body 10 out of 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.

[0022] Figure 2 is a cross-sectional view of the electrode body in Figure 1, viewed in the direction of the arrow II-II. Figure 3 is a cross-sectional view of the electrode body in Figure 1, viewed in the direction of the arrow III-III. Figure 4 is a schematic cross-sectional view of the electrode body in Figure 1, partially viewed in the direction of the arrow IV-IV. As shown in Figures 1 to 4, the electrode body 10 includes a first electrode 11A, a second electrode 11B, and a separator 12. The electrode body 10 is wound such that the first electrode 11A, the second electrode 11B, and the separator 12 surround a winding axis Z. Thus, in this embodiment, the electrode body 10 is a so-called wound electrode body. However, the electrode body 10 may also be a laminated electrode body in which the first electrode 11A, the second electrode 11B, and the separator 12 are stacked in one direction (for example, a third direction D3). In Figures 2 to 4, the separator 12 is schematically shown by a dashed line.

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

[0024] In this embodiment, the first electrode 11A is the positive electrode and the second electrode 11B is the negative electrode. However, the first electrode 11A may be the negative electrode and the second electrode 11B may be the positive electrode.

[0025] The separator 12 is provided between the first electrode 11A and the second electrode 11B. The separator 12 separates the first electrode 11A and the second electrode 11B while allowing ions to move between them. The ions are, for example, lithium ions. The separator 12 has electrical insulating properties.

[0026] Of the first electrode 11A, the second electrode 11B, and the separator 12, the separator 12 is located on the innermost side with respect to the winding axis Z. Also, of the first electrode 11A, the second electrode 11B, and the separator 12, the separator 12 is located on the outermost side with respect to the winding axis Z. The outer edge of the separator 12 in the winding direction DR is fixed by a tape member 13 placed on the outer surface of the separator 12.

[0027] The separator 12 may contain, for example, a polyolefin resin. The separator 12 may be substantially made of a polyolefin resin. The polyolefin resin may contain, for example, at least one selected from the group consisting of polyethylene (PE) and polypropylene (PP).

[0028] Figure 5 is an unfolded view of the first electrode. That is, Figure 5 shows the state of the first electrode 11A before it is wound. Figure 6 is a partial cross-sectional view showing an enlarged view of region VI of the first electrode in Figure 3. As shown in Figures 3 to 6, the first electrode 11A includes a current collector 100A, one-sided active material layer 200A, the other-sided active material layer 300A, a first protective part 400, and a second protective part 500.

[0029] The first current collector 100A includes an insulating support layer 110, a plurality of conductive support layers 120, a first conductive layer 130, a plurality of tab portions 140, a second conductive layer 150, and a plurality of bonding auxiliary portions 160.

[0030] The insulating 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 member and an electrically insulating member. As a result, the first current collector 100A is lighter compared to the case where the first current collector 100A is made entirely of metal, and the overall safety of the battery 1 is enhanced.

[0031] The insulating 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 insulating support layer 110 is made of a resin composition containing a polyester resin. It is even more preferable that the insulating 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 insulating support layer 110. Consequently, the insulating support layer 110 can be made relatively thin.

[0032] The orthogonal direction DO, which is perpendicular 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.

[0033] 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 the surface facing one side of the thickness direction DT of the insulating support layer 110. The second surface 113 is the surface facing the other side of the thickness direction DT of the insulating support layer 110.

[0034] 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, in order to reduce the overall thickness of the electrode body 10. The thickness of the insulating support layer 110 is not particularly limited as long as it has the desired rigidity. The thickness of the insulating support layer 110 may be, for example, 2 μm or more.

[0035] As shown in Figure 5, the multiple conductive support layers 120 are aligned in the winding direction DR of the electrode body 10. The multiple conductive support layers 120 are spaced apart from each other. The configuration of each of the multiple conductive support layers 120 will be described below.

[0036] As shown in Figure 6, the conductive support layer 120 is adjacent to the insulating support layer 110. More specifically, the conductive support layer 120 is adjacent to the insulating support layer 110 in the orthogonal direction DO (first direction D1). The thickness direction of the conductive support layer 120 is the same direction as the thickness direction DT of the insulating support layer 110. The conductive support layer 120 is in contact with the end face 111.

[0037] The conductive support layer 120 is conductive. The material constituting the conductive support layer 120 is not particularly limited. It may be a metal such as aluminum or copper, or a conductive resin. The conductive resin may be conductive by containing a highly conductive filler such as carbon or metal.

[0038] 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. This allows the first conductive layer 130 and the second conductive layer 150, described later, to spread uniformly and substantially parallel 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. The thickness of the conductive support layer 120 may be, for example, 2 μm or more.

[0039] The first conductive layer 130 is laminated on both the insulating support layer 110 and the conductive support layer 120. The first conductive layer 130 is provided on the 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 so as to protrude from the first surface 112. The extension direction DE, which is the direction in which the first conductive layer 130 extends from the insulating support layer 110, is the direction in which the end face 111 faces. The extension direction DE may be along the first direction D1 or along the orthogonal direction DO. Multiple conductive support layers 120 are laminated on each of the multiple extending portions of the first conductive layer 130.

[0040] In this embodiment, the first conductive layer 130 is located on the side of the winding axis Z when viewed from the insulating support layer 110. However, the first conductive layer 130 may be located on the opposite side from the winding axis Z when viewed from the insulating support layer 110.

[0041] As shown in Figure 5, the multiple tab portions 140 are aligned in the winding direction DR of the electrode body 10. The multiple tab portions 140 are spaced apart from each other. The multiple tab portions 140 are aligned in the thickness direction DT so as to correspond one-to-one with the multiple conductive support layers 120.

[0042] As shown in Figure 3, the multiple tab portions 140 are joined to each other by ultrasonic bonding or the like. Furthermore, as shown in Figure 1, the multiple tab portions 140 are joined to the first connecting member 40A by ultrasonic bonding or the like. As a result, the first external terminal 30A is electrically connected to the tab portion 140. The configuration of each of the multiple tab portions 140 will be described below.

[0043] As shown in Figure 6, the tab portion 140 is aligned with the conductive support layer 120 via the first conductive layer 130. The tab portion 140 is joined to the first conductive layer 130 by ultrasonic bonding. In Figure 6, the first bonding portion J1, which is the joint between the first conductive layer 130 and the tab portion 140, is shown. The tab portion 140 extends from the first conductive layer 130 in the extension direction DE. The edge of the tab portion 140 opposite to the extension direction DE is aligned with the end face 111 in the thickness direction DT.

[0044] 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 provided on the second surface 113 of the insulating support layer 110. The second conductive layer 150 is laminated 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 so as to protrude 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 extension direction DE in which the first conductive layer 130 extends from the insulating support layer 110. 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 laminated on each of the multiple extending portions of the second conductive layer 150.

[0045] As shown in Figure 5, the multiple bonding support portions 160 are arranged in the winding direction DR of the electrode body 10. The multiple bonding support portions 160 are spaced apart from each other. The multiple bonding support portions 160 are arranged in the thickness direction DT in a one-to-one correspondence with the multiple conductive support layers 120. Each of the multiple bonding support portions 160 has the same outer shape as the conductive support layers 120 arranged in the thickness direction DT when viewed from the thickness direction DT. The configuration of the multiple bonding support portions 160 will be described below.

[0046] As shown in Figure 6, the bonding auxiliary portion 160 is aligned with the tab portion 140 via 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. In Figure 6, the second bonding portion J2, which is the bonding portion between the second conductive layer 150 and the bonding auxiliary portion 160, is shown. The edge of the bonding auxiliary portion 160 facing the extension direction DE is aligned with the 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 edge of the bonding auxiliary portion 160 facing away from the extension direction DE is aligned with the end face 111 in the thickness direction DT.

[0047] 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. The thicknesses of the first conductive layer 130 and 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 reduce the overall thickness of the electrode body 10. The thicknesses of the first conductive layer 130 and the second conductive layer 150 are, for example, 0.1 μm or more, in order to prevent the electrical resistance of the first conductive layer 130 and the second conductive layer 150 from becoming too large. Note that if the thicknesses of the first conductive layer 130 and the second conductive layer 150 are 5 μm or less, it is difficult to directly weld the first conductive layer 130 and the second conductive layer 150 to each other or to directly join them to each other by ultrasonic welding.

[0048] The thickness of the tab portion 140 and the bonding support portion 160 are not particularly limited as long as they are thick enough for ultrasonic bonding. The thickness of the tab portion 140 and the bonding support portion 160 are 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 support portion 160 are 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 support portion 160 are not particularly limited as long as they have the desired rigidity. The thickness of the tab portion 140 and the bonding support portion 160 may be, for example, 2 μm or more.

[0049] The method for forming the first conductive layer 130 and the second conductive layer 150 is not particularly limited. In this embodiment, the first conductive layer 130 and the second conductive layer 150 are typically made of a metal film. This allows the first conductive layer 130 and the second conductive layer 150 to be easily laminated onto both the insulating support layer 110 and the conductive support layer 120. The metal film may typically be manufactured by extrusion molding. The first conductive layer 130 and the second conductive layer 150 may be bonded to the insulating support layer 110 and the conductive support layer 120 with an adhesive, or they may be pressed onto the insulating support layer 110 and the conductive support layer 120 by mechanical roll pressing. Also, the first conductive layer 130 and the second conductive layer 150 are typically made of a metal containing aluminum. This allows the first current collector 100A, which includes the first conductive layer 130 and the second conductive layer 150, to be suitably used as a positive electrode current collector. Furthermore, the first current collector 100A may be a negative electrode current collector, and the first conductive layer 130 and the second conductive layer 150 may be made of a metal containing copper.

[0050] The materials constituting the tab portion 140 and the joining auxiliary portion 160 are not particularly limited, but in this embodiment, the joining auxiliary portion 160 is made of the same material as the tab portion 140. The tab portion 140 and the joining auxiliary portion 160 are made of, for example, a metal film, and are typically made of a metal containing aluminum or copper.

[0051] One active material layer 200A is laminated on the first conductive layer 130. The other active material layer 300A is laminated on the second conductive layer 150. Both the one active material layer 200A and the other active material layer 300A are positive electrode active material layers, but they may also be negative electrode active material layers. The one active material layer 200A is separated from the tab portion 140. The other active material layer 300A is separated from the bonding auxiliary portion 160.

[0052] The separator 12 is laminated on one side of the active material layer 200A in the radial direction centered on the winding axis Z (see Figure 3, etc.). The separator 12 is also laminated on the other side of the active material layer 300A in the same radial direction.

[0053] The first protective portion 400 is made of an electrically insulating ceramic. The first protective portion 400 covers a portion of the one-side active material layer 200A on the DE side in the extension direction. The first protective portion 400 covers the entire surface of the first conductive layer 130 between the one-side active material layer 200A and the tab portion 140. The first protective portion 400 is not located between the first conductive layer 130 and the tab portion 140.

[0054] The second protective portion 500 is made of an electrically insulating ceramic. The second protective portion 500 covers a portion of the other active material layer 300A on the DE side in the extension direction. The second protective portion 500 covers the entire surface of the second conductive layer 150 between the other active material layer 300A and the bonding auxiliary portion 160. The second protective portion 500 is not located between the second conductive layer 150 and the bonding auxiliary portion 160.

[0055] As shown in Figures 2 to 4, the second electrode 11B is laminated in the radial direction on one side of the active material layer 200A via a separator 12. The second electrode 11B is also laminated on the other side of the active material layer 300A via a separator 12. In this embodiment, the electrode body 10 includes multiple separators 12, but it may also include a single separator 12.

[0056] The second electrode 11B includes a second current collector 100B and a second active material layer 200B. The second current collector 100B includes a conductive support portion 170 and a plurality of second tab portions 180 (see Figure 4). The conductive support portion 170 extends along the orthogonal direction DO (first direction D1). The plurality of second tab portions 180 extend from the upper end of the conductive support portion 170. The plurality of second tab portions 180 are joined to each other by ultrasonic welding and are also joined to the second connecting member 40B (see Figure 1).

[0057] The multiple second tab portions 180 and conductive support portions 170 are made of an integral material, for example, a metal film. In this embodiment, the multiple second tab portions 180 and conductive support portions 170 are made of a metal including copper, for example. This allows the second current collector 100B to be suitably used as a negative electrode current collector. If the first current collector 100A is a negative electrode current collector and the second current collector 100B is a positive electrode current collector, the multiple second tab portions 180 and conductive support portions 170 may be made of a metal including aluminum.

[0058] The second active material layer 200B is laminated on both sides of the conductive support portion 170 of the second current collector 100B. In this embodiment, the second electrode 11B is the negative electrode. Therefore, the second active material layer 200B is the negative electrode active material layer. The second active material layer 200B may also be the positive electrode active material layer.

[0059] As described above, in a battery 1 according to one embodiment of the present disclosure, the current collector 100A comprises an insulating support layer 110, a conductive support layer 120, a first conductive layer 130, and a tab portion 140. The insulating support layer 110 is made of an electrically insulating resin composition. The conductive support layer 120 is adjacent to the insulating support layer 110. The first conductive layer 130 is laminated on both the insulating support layer 110 and the conductive support layer 120. The tab portion 140 is aligned with the conductive support layer 120 via the first conductive layer 130 and is joined to the first conductive layer 130 by ultrasonic bonding.

[0060] As described above, when the tab portion 140 and the first conductive layer 130 are joined to each other by ultrasonic welding, the conductive support layer 120 may be mixed into the first joint portion J1, which is the joint between the first conductive layer 130 and the tab portion 140. As a result, the tab portion 140 and the first conductive layer 130 may not be joined uniformly to each other in the first joint portion J1. However, since the conductive support layer is conductive, even if the tab portion 140 and the first conductive layer 130 are not joined uniformly to each other, the impediment to conductivity in the first joint portion J1 is suppressed. Therefore, according to the above configuration, heat generation in the first joint portion J1, which is the joint between the first conductive layer 130 and the tab portion 140, is reduced. Furthermore, by forming the conductive support layer 120 using a material with a higher melting point than the insulating support layer 110, the melting of the conductive support layer 120 can be suppressed. As a result, the joining of the first conductive layer 130 and the tab portion 140 in the first joint portion J1 becomes relatively uniform. Therefore, with the above configuration, the joint strength of the first joint portion J1 can be improved.

[0061] Furthermore, a current collector 100A according to one embodiment of the present disclosure further comprises a second conductive layer 150 and a bonding auxiliary portion 160. The second conductive layer 150 is laminated on both the insulating support layer 110 and the conductive support layer 120, and is located opposite 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 material constituting the tab portion 140. The bonding auxiliary portion 160 is aligned with the tab portion 140 via 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.

[0062] According to the above configuration, by forming the second bonding portion J2, which is the bonding portion between the bonding auxiliary portion 160 and the second conductive layer 150 by ultrasonic bonding, at the same time as the first bonding portion J1, it is possible to improve the uniformity of the bonding of the first bonding portion J1 and the second bonding portion J2 at a lower cost. Consequently, heat generation in the second bonding portion J2 and the first bonding portion J1 can be reduced along the conductive path from the second conductive layer 150 to the tab portion 140. The first bonding portion J1 and the second bonding portion J2 can be formed, for example, by sandwiching a horn and anvil (neither shown) for ultrasonic bonding between the conductive support layer 120, the first conductive layer 130, the tab portion 140, the second conductive layer 150, and the bonding auxiliary portion 160 in the region R where they are stacked on top of each other.

[0063] Furthermore, in a battery 1 according to one embodiment of the present 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 an electrically insulating ceramic. The first protective portion 400 covers a part of the one-side active material layer 200A, covers the entire surface of the first conductive layer 130 between the one-side active material layer 200A and the tab portion 140, and is not positioned between the first conductive layer 130 and the tab portion 140. The second protective portion 500 is made of an electrically insulating ceramic. The second protective portion 500 covers a part of the other-side active material layer 300A, covers the entire surface of the second conductive layer 150 between the other-side active material layer 300A and the bonding auxiliary portion 160, and is not positioned between the second conductive layer 150 and the bonding auxiliary portion 160.

[0064] With the above configuration, the first protective part 400 can prevent metallic foreign matter generated by the joining of the tab portion 140 with other members from coming into contact with the first conductive layer 130 or the one-sided active material layer 200A. Furthermore, since the first protective part 400 is not positioned between the first conductive layer 130 and the tab portion 140, the first conductive layer 130 and the tab portion 140 can be brought into close contact when forming the first joint portion J1. Consequently, a decrease in the bonding strength of the first joint portion J1 can be suppressed. In addition, the second protective part 500 can prevent metallic foreign matter generated by the joining of the tab portion 140 with other members from coming into contact with the second conductive layer 150 or the other-sided active material layer 300A. Furthermore, since the second protective part 500 is not positioned between the second conductive layer 150 and the bonding auxiliary part 160, the first conductive layer 130 and the tab portion 140 can be brought into close contact when forming the first joint portion J1 together with the second joint portion J2. Consequently, the decrease in the joint strength of the second joint portion J2 can be suppressed.

[0065] In the above-described embodiment, the combinatable configurations may be combined with each other.

[0066] 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]

[0067] 1 Battery, 10 Electrode body, 11A First electrode, 11B Second electrode, 12 Separator, 13 Tape member, 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 Insulating support layer, 111 End face, 112 First surface, 113 Second surface, 120 Conductive support layer, 130 First conductive layer, 140 Tab portion, 150 Second conductive layer, 160 Joining auxiliary portion, 170 Conductive support portion, 180 Second tab portion, 200A One-sided active material layer, 200B Second active material layer, 300A Other side active material layer, 400 first protective part, 500 second protective part, D1 first direction, D2 second direction, D3 third direction, DE extension direction, DO orthogonal direction, DR winding direction, DT thickness direction, J1 first joint portion, J2 second joint portion, R region, Z winding axis.

Claims

1. It is a current collector, Insulating support layer, A conductive support layer, First conductive layer and Equipped with a tab section, The insulating support layer is made of an electrically insulating resin composition. 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 aligned with the conductive support layer via the first conductive layer and is joined to the first conductive layer by ultrasonic bonding, in a current collector.

2. The second conductive layer, It further includes a joining support part, The second conductive layer is laminated on 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 aforementioned joining support portion is made of the same material as the material that constitutes the tab portion. The current collector according to claim 1, wherein the bonding auxiliary portion is aligned with the tab portion via 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. 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 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 portion. The insulating support layer is made of an electrically insulating resin composition. 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 aligned with the conductive support layer via the first conductive layer and is joined to the first conductive layer by ultrasonic bonding. The aforementioned one-sided active material layer is laminated on the first conductive layer, The separator is laminated on the one-sided active material layer, The second electrode is laminated on the one-sided active material layer via the separator. The external terminal is a battery that is electrically connected to the tab portion.

4. The first electrode further includes the other side active material layer, The current collector further includes a second conductive layer and a bonding auxiliary portion. The second conductive layer is laminated on 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 aforementioned joining support portion is made of the same material as the material that constitutes the tab portion. The bonding auxiliary portion is aligned with the tab portion via 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 other active material layer is laminated on the second conductive layer, The separator is further laminated on the other active material layer. The battery according to claim 3, wherein the second electrode is further laminated on the other active material layer via the separator.

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

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