Current collector and battery

Abstract

To provide a current collector that is thin and has low electrical resistance in the conductive part. [Solution] The current collector 100A according to the present disclosure comprises a support portion 110 and a conductive portion 120. The support portion 110 is made of an electrically insulating resin composition. 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 positioned 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.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The thickness of the current collector to which the electrical connection member is connected is relatively thick. As a result, the volume ratio of the current collector in the entire battery becomes high, and the energy density of the battery becomes small. Further, in order to improve the energy density of the battery, when the active material layer is enlarged and the intermediate welding region is reduced, the electrical resistance in the intermediate welding region increases.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a current collector that is thin and can reduce the electrical resistance in the conductive portion.

Means for Solving the Problems

[0006] A current collector according to a certain aspect of the present disclosure comprises 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 positioned 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.

[0007] In a current collector according to a certain aspect of this disclosure, preferably, the third conductive layer is separated from the support portion.

[0008] In a current collector according to a certain aspect of the present disclosure, preferably, the thickness of the third conductive layer is substantially equal to the thickness of the support portion.

[0009] In a current collector according to a certain aspect of this disclosure, preferably, 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.

[0010] A battery according to a certain aspect of this disclosure comprises an electrode body, an external terminal, and a coupling. 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 and a conductive part. The support is made of an electrically insulating resin composition. The conductive part includes a first conductive layer, a second conductive layer, and a third conductive layer. The first and second conductive layers extend from the support. The third conductive layer is positioned 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. The active material layer is laminated to the first conductive layer. The separator is laminated to the active material layer. The second electrode is laminated to the active material layer via the separator. The external terminal is electrically connected to the coupling. The coupling is bonded to the third conductive layer.

[0011] In a battery according to a certain aspect of this disclosure, preferably, the third conductive layer is separated from the support portion.

[0012] In a battery according to a certain aspect of this disclosure, preferably, the thickness of the third conductive layer is substantially equal to the thickness of the support portion.

[0013] In a battery according to a certain aspect of this disclosure, preferably, 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.

[0014] In a battery according to a certain aspect of this disclosure, preferably, the support portion has a support edge. The support edge is oriented in the direction of extension. The extension 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 is oriented in the direction of extension. The active material edge is aligned with the support edge in the thickness direction of the support portion. [Effects of the Invention]

[0015] According to this disclosure, it is possible to provide a current collector that is thin in thickness and has low electrical resistance in the conductive part. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view showing a battery according to Embodiment 1. [Figure 2] This is a disassembled perspective view of the battery according to Embodiment 1. [Figure 3] Figure 1 is a cross-sectional view of the battery as seen in the direction of the arrow III-III. [Figure 4] Figure 3 is a cross-sectional view of the electrode body as seen in the direction of the IV-IV line arrow. [Figure 5] Figure 3 is a cross-sectional view of the electrode body as seen in the direction of the VV arrow. [Figure 6] Figure 3 is a schematic cross-sectional view of the electrode body, partially viewed in the direction of the arrow along the line VI-VI. [Figure 7] This is a diagram of the first electrode. [Figure 8] This is a magnified partial cross-sectional view of region VIII of the first electrode in Figure 5. [Modes for carrying out the invention]

[0017] The current collector and the battery according to an embodiment of the present disclosure will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

[0018] FIG. 1 is a perspective view showing a battery according to Embodiment 1. As shown in FIG. 1, the battery 1 according to Embodiment 1 is a so-called rectangular battery. The battery 1 may be a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a nickel-hydrogen battery. The battery 1 can be used, for example, as a cell included in a power storage module mounted on an electric vehicle.

[0019] FIG. 2 is an exploded perspective view of the battery according to Embodiment 1. FIG. 3 is a cross-sectional view of the battery of FIG. 1 as viewed in the direction of the arrow III-III. As shown in FIGS. 1 to 3, the battery 1 according to an embodiment of the present disclosure includes an electrode body 10, a case 20, a first external terminal 30A, a second external terminal 30B, a first connection portion 40A, a second connection portion 40B, a first seal ring 50A, a second seal 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 components of the battery 1 other than the electrode body 10 will be described.

[0020] The case 20 has conductivity. The conductive portion of the case 20 is made of a metal such as aluminum, for example. The case 20 houses the electrode body 10. The case 20 also houses an electrolytic solution (not shown).

[0021] The 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 stands up from the bottom wall 21a.

[0022] The bottom wall 21a includes the bottom body 21aa, the pressure relief valve 21ab, the outer protective film 21ac, and the inner protective film 21ad. The peripheral wall 21b rises from the bottom body 21aa. The pressure relief valve 21ab is provided on the bottom body 21aa. The outer protective film 21ac covers the pressure relief valve 21ab from the outside. The inner protective film covers the pressure relief valve 21ab from the inside. The bottom body 21aa and the pressure relief valve 21ab are made of a metal such as aluminum.

[0023] An opening is formed at the upper end of the peripheral wall 21b. The peripheral wall 21b has a substantially rectangular outer shape when viewed from the direction of the opening. The opening and the bottom wall 21a are aligned in a first direction D1. The first direction D1 may be the height direction or vertical direction of the battery 1. The peripheral wall 21b is made of a metal such as aluminum.

[0024] The lid 22 includes a lid body 22a, a sealing plug 22b, a plug cover 22c, and an insulating cover 22d.

[0025] The lid body 22a is joined to the peripheral wall 21b by welding or the like so as to close the opening in the peripheral wall 21b. The lid body 22a has a first connecting hole 22aa, a second connecting hole 22ab, and an electrolyte injection hole 22ac formed therein. The electrolyte injection hole 22ac is a through hole for injecting electrolyte into the case body 21 during the manufacturing process of the battery 1.

[0026] The sealing plug 22b seals the injection hole 22ac. The plug cover 22c covers the injection hole 22ac and the sealing plug 22b. The insulating cover 22d covers the injection hole 22ac, the sealing plug 22b, and the plug cover 22c.

[0027] The first external terminal 30A and the second external terminal 30B are provided so as to be exposed to the outside in the battery 1. The first connecting 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 located inside the case 20.

[0028] The first external terminal 30A or the first connecting portion 40A is inserted through the first connecting hole 22aa. The first external terminal 30A is electrically connected to the first connecting portion 40A. Specifically, the first external terminal 30A and the first connecting portion 40A are joined to each other. The first connecting portion 40A is joined to the electrode body 10. As a result, the first external terminal 30A is electrically connected to the electrode body 10.

[0029] The second external terminal 30B or the second connecting portion 40B is inserted through the second connecting hole 22ab. The second external terminal 30B is electrically connected to the second connecting portion 40B. Specifically, the second external terminal 30B and the second connecting portion 40B are joined to each other. The second connecting portion 40B is joined to the electrode body 10. As a result, the second external terminal 30B is electrically connected to the electrode body 10.

[0030] 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 aligned in the second direction D2. The second direction D2 is perpendicular to the first direction D1.

[0031] The first seal ring 50A is provided along the first connecting hole 22aa. The first seal ring 50A is provided in the gap between the lid body 22a and the first external terminal 30A, and seals this gap. The second seal ring 50B is provided along the second connecting hole 22ab. The second seal ring 50B is provided in the gap between the lid body 22a and the second external terminal 30B, and seals this gap. The first seal ring 50A and the second seal ring 50B have electrical insulating properties.

[0032] The first terminal support portion 60A is locked to the lid body 22a. The first terminal support portion 60A supports the first external terminal 30A from the outer circumference of the first external terminal 30A. The first terminal support portion 60A includes a first locking ring 61A and a first covering ring 62A. The first locking ring 61A extends in an annular shape so as to surround the first connecting hole 22aa and is locked directly to the lid 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 material that is electrically insulating or has relatively weak conductivity.

[0033] The second terminal support portion 60B is locked to the lid body 22a. The second terminal support portion 60B supports the second external terminal 30B from the outer circumference of the second external terminal 30B. The second terminal support portion 60B includes a second locking ring 61B and a second covering ring 62B. The second locking ring 61B extends in an annular shape so as to surround the second connecting hole 22ab and is locked directly to the lid 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 material.

[0034] The insulating member 70 has electrical insulating properties. The insulating member 70 is placed between the electrode body 10 and the case 20. The insulating member 70 electrically insulates the electrode body 10 and the case 20 from each other. The insulating member 70 includes an insulating bracket 71, a circumferential insulating portion 72, a bottom insulating portion 73, and an insulating tape 74.

[0035] The insulating bracket 71 is positioned between the electrode body 10 and the lid body 22a. The insulating bracket 71 is relatively rigid and is in contact with both the electrode body 10 and the lid body 22a. As a result, the electrode body 10 is fixed to the case 20 in the first direction D1.

[0036] The circumferential insulating portion 72 is positioned between the electrode body 10 and the circumferential wall 21b. The circumferential insulating portion 72 is made of a film-like material.

[0037] The bottom insulating portion 73 is positioned between the electrode body 10 and the bottom wall 21a. The bottom insulating portion 73 is made of a film-like material.

[0038] The insulating tape 74 is adhered to both the circumferential insulating portion 72 and the bottom insulating portion 73. The insulating tape 74 fixes the circumferential insulating portion 72 and the bottom insulating portion 73 to each other.

[0039] As shown in Figure 2, the battery 1 according to this embodiment comprises a plurality of electrode bodies 10. Typically, the battery 1 comprises two electrode bodies 10. These electrode bodies 10 are aligned in a third direction D3. The third direction D3 is perpendicular to both the first direction D1 and the second direction D2. The circumferential insulating portion 72 may integrally cover the plurality of electrode bodies 10 so that these electrode bodies 10 are fixed to each other.

[0040] In the following description, one of the multiple electrode bodies 10 will be explained. Note that each of the multiple electrode bodies 10 may have the configuration shown below.

[0041] Figure 4 is a cross-sectional view of the electrode body in Figure 3, viewed in the direction of the IV-IV arrow. Figure 5 is a cross-sectional view of the electrode body in Figure 3, viewed in the direction of the VV arrow. Figure 6 is a schematic cross-sectional view of the electrode body in Figure 3, partially viewed in the direction of the VI-VI arrow. As shown in Figures 2 to 6, the electrode body 10 includes a first electrode 11A, a second electrode 11B, and a separator 12. The electrode body 10 is wound such that the first electrode 11A, the second electrode 11B, and the separator 12 surround the 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 4 to 6, the separator 12 is schematically shown by a dashed line.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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).

[0047] The first electrode 11A includes a first current collector 100A, a first active material layer 200A, and a protective part 300.

[0048] Figure 7 is an unfolded view of the first electrode. That is, Figure 7 shows the state of the first electrode 11A before it is wound. Figure 8 is a partial cross-sectional view showing an enlarged view of region VIII of the first electrode in Figure 5. As shown in Figures 7 and 8, the first current collector 100A includes a support portion 110 and a conductive portion 120.

[0049] The support portion 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. Furthermore, the support portion 110 is made of a material that is more rigid than the separator 12. The support portion 110 is made of a resin composition that includes, for example, a polyamide resin, a polyester resin, or a polyolefin resin. To increase rigidity, it is preferable that the support portion 110 is made of a resin composition that includes a polyester resin. It is even more preferable that the support portion 110 is substantially made of a polyester resin. The polyester resin may be, for example, polyethylene terephthalate. This makes it possible to increase the rigidity of the first current collector 100A while maintaining the electrical insulation properties of the support portion 110. Consequently, the support portion 110 can be made relatively thin.

[0050] The orthogonal direction DO, which is perpendicular 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.

[0051] The support portion 110 has a support edge 110e, a first support surface 111, and a second support surface 112. The support edge 110e faces one side of the first direction D1. The support edge 110e extends along the winding direction DR of the electrode body 10. The first support surface 111 is the surface facing one side of the thickness direction DT of the support portion 110. The second support surface 112 is the surface facing the other side of the thickness direction DT of the support portion 110.

[0052] 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, in order to reduce the overall thickness of the electrode body 10. The thickness of the support portion 110 is not particularly limited as long as it has the desired rigidity. The thickness of the support portion 110 may be, for example, 2 μm or more.

[0053] As shown in Figures 5 to 8, the conductive portion 120 includes a first conductive layer 121, a second conductive layer 122, and a plurality of third conductive layers 123.

[0054] The first conductive layer 121 is provided on the first support surface 111 of the support portion 110 (see Figure 8). The first conductive layer 121 extends from the support portion 110. More specifically, the first conductive layer 121 extends so as to protrude from the first support surface 111. The extension direction DE, which is the direction in which the first conductive layer 121 extends from the support portion 110, is the direction in which the support edge 110e faces. The extension direction DE may be along the first direction D1 or along the orthogonal direction DO.

[0055] In this embodiment, the first conductive layer 121 is located on the side of the winding axis Z when viewed from the support portion 110. Furthermore, the first conductive layer 121 is in contact with the support portion 110 over the entire surface of the first support surface 111.

[0056] The second conductive layer 122 is provided 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 so as to protrude 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 extension direction DE in which the first conductive layer 121 extends from the support portion 110. The extension length of the second conductive layer 122 extending from the support portion 110 is substantially equal to, but may be different from, the extension length of the first conductive layer 121 extending from the support portion 110.

[0057] In this embodiment, the second conductive layer 122 is located on the side opposite to the winding axis Z when viewed from the support portion 110. Furthermore, the second conductive layer 122 is in contact with the support portion 110 over the entire surface of the second support surface 112.

[0058] Furthermore, in this embodiment, the first conductive layer 121 has a plurality of extended portions (see Figure 7). The second conductive layer 122 also has a plurality of extended portions. The plurality of extended portions of the first conductive layer 121 are arranged in a one-to-one correspondence with the plurality of extended portions of the second conductive layer 122 in the thickness direction DT.

[0059] Multiple third conductive layers 123 are arranged between the first conductive layer 121 and the second conductive layer 122 (see Figures 7 and 8). Multiple third conductive layers 123 are bonded to both the first conductive layer 121 and the second conductive layer 122. Each of the multiple third conductive layers 123 extends from between the first conductive layer 121 and the second conductive layer 122. Multiple third conductive layers 123 face the support edge 110e of the support portion 110. Multiple third conductive layers 123 are spaced apart from the support edge 110e of the support portion 110. Multiple third conductive layers 123 may be in contact with the support edge 110e of the support portion 110.

[0060] The multiple third conductive layers 123 are arranged in the thickness direction DT so as to correspond one-to-one with the multiple extensions of the first conductive layer 121 (see Figure 7). The multiple third conductive layers 123 are also arranged in the thickness direction DT so as to correspond one-to-one with the multiple extensions of the second conductive layer 122. Furthermore, the multiple third conductive layers 123 are joined to the first conductive layer 121 and the second conductive layer 122, for example, by ultrasonic welding.

[0061] Multiple third conductive layers 123 are arranged so as to be aligned with each other in the third direction D3 (see 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 Figures 2 and 3).

[0062] The thickness of the first conductive layer 121 is thinner than the thickness of the third conductive layer 123 and thinner than the thickness of the support portion 110 (see Figure 8). The thickness of the second conductive layer 122 is thinner than the thickness of the third conductive layer 123 and thinner than the thickness of the support portion 110. 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, in order to reduce the overall thickness of the electrode body 10. The thicknesses of the first conductive layer 121 and the second conductive layer 122 may be, for example, 0.1 μm or more, in order to prevent the electrical resistance of the first conductive layer 121 and the second conductive layer 122 from becoming too high. 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 be greater than 5 μm.

[0063] Furthermore, if the thickness of the first conductive layer 121 and the second conductive layer 122 are 5 μm or less, it is difficult to directly weld the first conductive layer 121 and the second conductive layer 122 to each other, or to directly join them to each other by ultrasonic welding. The thickness of the third conductive layer 123 is substantially equal to the thickness of the support portion 110.

[0064] The method for forming the first conductive layer 121, the second conductive layer 122, and the third conductive layer 123 is 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 so as to extend from the support portion 110. The metal film may typically be manufactured by extrusion molding. The first conductive layer 121 and the second conductive layer 122 may be bonded to the support portion 110 with an adhesive, or they may be pressed to the support portion 110 by a mechanical roll press. Also, the first conductive layer 121, the second conductive layer 122, and the third conductive layer 123 are typically made of a metal containing aluminum. Thus, the first current collector 100A having the conductive portion 120 can 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 121, the second conductive layer 122, and the third conductive layer 123 may be made of a metal containing copper.

[0065] The first active material layer 200A is laminated on the first conductive layer 121. The first active material layer 200A is a positive electrode active material layer, but may also be a negative electrode active material layer. In this embodiment, the first active material layer 200A is also laminated on the 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 laminated on the first conductive layer 121. The first outer active material layer 220A is laminated on the second conductive layer 122.

[0066] The first active material layer 200A has an active material edge 200Ae. The active material edge 200Ae is oriented in the extension direction DE. The active material edge 200Ae is aligned with the support edge 110e in the thickness direction DT of the support portion 110. More specifically, the active material edge 200Ae of the first inner active material layer 210A is aligned with the support edge 110e in the thickness direction DT. The active material edge 200Ae of the first outer active material layer 220 is aligned with the support edge 110e in the thickness direction DT.

[0067] The separator 12 is laminated on the first active material layer 200A in the radial direction centered on the winding axis Z (see Figure 5, etc.). The separator 12 is laminated on the first inner active material layer 210A in the same radial direction. The separator 12 is also laminated on the first outer active material layer 220A in the same radial direction.

[0068] The protective part 300 has electrical insulating properties and is made of, for example, ceramic. The protective part 300 covers the upper part of the first active material layer 200A. The protective part 300 covers the edge 200Ae of the active material.

[0069] The protective section 300 includes an inner protective section 310 and an outer protective section 320. The inner protective section 310 covers the upper part of the first inner active material layer 210A. The outer protective section 320 covers the upper part of the first outer active material layer 220A.

[0070] The inner protective portion 310 is further provided on the first conductive layer 121 on the side opposite to the third conductive layer 123 when viewed from the first conductive layer 121. Therefore, the protective portion 300 is not located on the conductive path from the first conductive layer 121 to the third conductive layer 123. Thus, an increase in the electrical resistance of the conductive portion 120 can be suppressed. Similarly, the outer protective portion 320 is further provided on the second conductive layer 122 on the side opposite to the third conductive layer 123 when viewed from the second conductive layer 122. Therefore, the protective portion 300 is not located on the conductive path from the second conductive layer 122 to the third conductive layer 123. Thus, an increase in the electrical resistance of the conductive portion 120 can be suppressed.

[0071] As shown in Figures 4 to 6, the second electrode 11B is laminated on the first active material layer 200A via the separator 12 in the radial direction. More specifically, the second electrode 11B is laminated on the first inner active material layer 210A via the separator 12, and is also laminated on the first outer active material layer 220A via the separator 12.

[0072] 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 Figure 6). The conductive support portion 140 extends along the orthogonal direction DO (first direction D1). The plurality of tabs 150 extend from the upper end of the conductive support portion 140. The plurality of tabs 150 are joined to each other by ultrasonic welding and are also joined to the second connecting portion 40B (see Figures 2 and 3).

[0073] The multiple tabs 150 and conductive support portion 140 are made of a single integrated material, for example, a metal film. In this embodiment, the multiple tabs 150 and conductive support portion 140 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 tabs 150 and conductive support portion 140 may be made of a metal including aluminum.

[0074] The second active material layer 200B is laminated on both sides of the conductive support portion 140 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.

[0075] As described above, a first current collector 100A according to one embodiment of the present disclosure comprises a support portion 110 and a conductive portion 120. The support portion 110 is made of an electrically insulating resin composition. 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.

[0076] With the above configuration, since the third conductive layer 123 is positioned between the first conductive layer 121 and the second conductive layer 122 extending from the support portion 110, the third conductive layer 123 can avoid 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 extended first conductive layer 121 and the second conductive layer 122, a wide bonding area with the first conductive layer 121 and the second conductive layer 122 can be secured. As a result, the electrical resistance in the conductive portion 120 can be reduced.

[0077] Furthermore, in this embodiment, the third conductive layer 123 is separated from the support portion 110. With this configuration, when the third conductive layer 123 is tilted with respect to the direction in which the support portion 110 extends, the first conductive layer 121 and the second conductive layer 122 can easily bend between the third conductive layer 123 and the support portion 110. This suppresses localized stress concentration in the first conductive layer 121 and the second conductive layer 122.

[0078] Furthermore, in this embodiment, the thickness of the third conductive layer 123 is substantially equal to the thickness of the support portion 110.

[0079] According to the above configuration, 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. Consequently, the strength of the conductive portion 120 is improved.

[0080] 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.

[0081] According to the above configuration, the thickness of the first current collector 100A can be made thinner while ensuring the bonding strength between the third conductive layer 123 and other members (typically the first connecting portion 40A).

[0082] Furthermore, in this embodiment, the battery 1 according to one embodiment of the present disclosure comprises 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 an electrically insulating resin composition. 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 positioned between the first conductive layer 121 and the second conductive layer 122, bonded to both the first and second conductive layers 121 and extending from between the first and second conductive layers 122. The first active material layer 200A is laminated on the first conductive layer 121. The separator 12 is laminated on the first active material layer 200A. The second electrode 11B is laminated on the first active material layer 200A via the separator 12. The first external terminal 30A is electrically connected to the first connecting portion 40A. The first connecting portion 40A is bonded to the third conductive layer 123.

[0083] According to the above configuration, the third conductive layer 123, which is joined to the first connecting portion 40A, is positioned between the first conductive layer 121 and the second conductive layer 122 extending from the support portion 110. Therefore, the third conductive layer 123 can avoid overlapping with the support portion 110 in the thickness direction DT of the support portion 110. This reduces the thickness of the first current collector 100A. Thus, by reducing the volume ratio of the first current collector 100A in 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 joining the extended first conductive layer 121 and the second conductive layer 122, the bonding region with the first conductive layer 121 and the second conductive layer 122 can be made wider. This reduces the electrical resistance in the conductive portion 120 and increases the volume of the first active material layer 200A, thereby improving the energy density of the battery 1.

[0084] Furthermore, in this embodiment, the support portion 110 has a support edge 110e. The support edge 110e is oriented in the extension direction DE. The extension 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 is oriented in the extension direction DE. The active material edge 200Ae is aligned with the support edge 110e in the thickness direction DT of the support portion 110.

[0085] According to the above configuration, the first active material layer 200A is firmly supported by the support portion 110 via the first conductive layer 121 up to the active material edge 200Ae. At the same time, the first active material layer 200A can extend in the extension direction DE to a position aligned with the support edge 110e. Consequently, the energy density of the battery 1 can be improved.

[0086] Furthermore, during the process of providing the first active material layer 200A on the first conductive layer 121, the first active material layer 200A may be compressed in the thickness direction DT together with the first conductive layer 121 and the support portion 110. In this case, with the above configuration, the portion of the first active material layer 200A near the active material edge 200Ae can be compressed more reliably together with the support portion 110.

[0087] In the above-described embodiment, the combinatable configurations may be combined with each other.

[0088] 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]

[0089] 1 Battery, 10 Electrode body, 11A First electrode, 11B Second electrode, 12 Separator, 13 Tape material, 20 Case, 21 Case body, 21a Bottom wall, 21aa Bottom body, 21ab Pressure relief valve, 21ac Outer protective film, 21ad Inner protective film, 21b Peripheral wall, 22 Lid, 22a Lid body, 22aa First connecting hole, 22ab Second connecting hole, 22ac Liquid injection hole, 22b Sealing plug, 22c Plug cover, 22d Insulating cover, 30A First external terminal, 30B Second external terminal, 40A First connecting part, 40B Second connecting part, 50A First sealing ring, 50B Second sealing ring, 60A First terminal support part, 60B Second terminal support part, 61A First locking ring, 61B Second locking ring, 62A First covering ring, 62B 1. Second covering ring, 70. Insulating member, 71. Insulating bracket, 72. Peripheral insulating part, 73. Bottom insulating part, 74. Insulating tape, 80. Fuse protection part, 100A. First current collector, 100B. Second current collector, 110. Support part, 110e. Support edge, 111. First support surface, 112. Second support surface, 120. Conductive part, 121. First conductive layer, 122. Second conductive layer, 123. Third conductive layer, 140. Conductive support part, 150. Tab, 200A. First active material layer, 200Ae. Active material edge, 210A. First inner active material layer, 220A. First outer active material layer, 200B. Second active material layer, 300. Protection part, 310. Inner protection part, 320. Outer protection part, D1. First direction, D2. Second direction, D3. Third direction, DE. Extension direction, DO. Orthogonal direction, DR winding direction, DT thickness direction, Z winding axis.

Claims

1. It is a current collector, Support part and It includes a 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, A current collector wherein 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 thickness of the first conductive layer is thinner than the thickness of the third conductive layer. The current collector according to any one of claims 1 to 3, wherein the thickness of the second conductive layer is thinner than the thickness of the third conductive layer.

5. It is a battery, Electrode body and External terminals, It includes a connecting part, The electrode body includes a first electrode, a second electrode, and a separator. The first electrode comprises a current collector and an active material layer. The current collector includes a support 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 positioned 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. 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 via the separator, The external terminal is electrically connected to the connecting portion. The aforementioned connecting portion is joined to the third conductive layer, and the battery.

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

9. The support portion has a support edge facing the extension direction, which is the direction in which the first conductive layer extends from the support portion. The active material layer has an active material edge facing the extension direction, The battery according to any one of claims 5 to 7, wherein the edge of the active material is aligned with the support edge in the thickness direction of the support portion.

Images