Current collector and battery

Abstract

The present invention provides a current collector that can improve the energy density of a battery when used as a component of that battery. [Solution] The current collector 100A comprises a support portion 110, a first conductive layer 120, and a second conductive layer 130. The support portion 110 is made of an electrically insulating resin composition. The support portion 110 includes a support layer 111 and an extension portion 112. The first conductive layer 120 is in contact with the support layer 111 on one side in the thickness direction DT of the support layer 111. The second conductive layer 130 is in contact with the support layer 111 on the other side in the thickness direction DT. The extension portion 112 extends from the support layer 111 in an orthogonal direction DO perpendicular to the thickness direction DT.

Description

Technical Field

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

Background Art

[0002] Japanese Patent Application Laid-Open No. 2024-510696 discloses an electrode plate used in a secondary battery. The electrode plate includes a current collector, an active material layer, and an electrical connection member. The current collector includes a support layer and a conductive layer provided on one surface of the support layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for further improvement in the energy density of batteries. From the perspective of improving the energy density of batteries, there is room for further improvement in the structure of the current collectors used in batteries.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a current collector that can improve the energy density of a battery when used as a component of the battery.

Means for Solving the Problems

[0006] A current collector according to an aspect of the present disclosure includes a support portion, a first conductive layer, and a second conductive layer. The support portion is made of a resin composition having electrical insulation. The support portion includes a support layer and an extension portion. The first conductive layer is in contact with the support layer on one side in the thickness direction of the support layer. The second conductive layer is in contact with the support layer on the other side in the thickness direction. The extension portion extends from the support layer in a direction orthogonal to the thickness direction.

[0007] In a current collector according to a certain aspect of the present disclosure, preferably, the extension is curved in at least one direction in the thickness direction.

[0008] In a current collector according to a certain aspect of the present disclosure, preferably, the extension includes a first extension and a second extension. The first and second extensions are aligned with each other in the thickness direction. The first extension is curved away from the second extension. The second extension is curved away from the first extension.

[0009] In a current collector according to a certain aspect of the present disclosure, preferably, pores are formed in the extension portion.

[0010] A battery according to a certain aspect of this disclosure comprises an electrode body and a case. The case is conductive. The case houses the electrode body. The electrode body includes a first electrode, a second electrode, and a separator. The first electrode includes a current collector and an active material layer. The current collector includes a support portion, a first conductive layer, and a second conductive layer. The support portion is made of an electrically insulating resin composition. The support portion includes a support layer and an extension portion. The first conductive layer is in contact with the support layer on one side in the thickness direction of the support layer. The second conductive layer is in contact with the support layer on the other side in the thickness direction. 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 extension portion extends from the support layer in an orthogonal direction perpendicular to the thickness direction.

[0011] In a battery according to a certain aspect of the present disclosure, preferably, the extension extends beyond the second electrode in the extension direction from the support layer.

[0012] In a battery according to a certain aspect of this disclosure, more preferably, the extension extends beyond the separator in the extension direction.

[0013] In a battery according to a certain aspect of this disclosure, preferably, the extension is curved in at least one direction in the thickness direction.

[0014] In a battery according to an aspect of the present disclosure, more preferably, the extending portion is aligned with the separator in the extending direction in which the extending portion extends from the support layer.

[0015] In a battery according to an aspect of the present disclosure, even more preferably, the extending portion is aligned with the second electrode in the extending direction.

[0016] In a battery according to an aspect of the present disclosure, preferably, the extending portion includes a first extending portion and a second extending portion. The first extending portion and the second extending portion are aligned with each other in the thickness direction. The first extending portion is bent toward the side opposite to the second extending portion side. The second extending portion is bent toward the side opposite to the first extending portion side.

[0017] In a battery according to an aspect of the present disclosure, preferably, pores are formed in the extending portion.

Advantages of the Invention

[0018] According to the present disclosure, it is possible to provide a current collector that can improve the energy density of a battery when used as a component of the battery.

Brief Description of the Drawings

[0019] [Figure 1] It is a perspective view showing a battery according to Embodiment 1. [Figure 2] It is an exploded perspective view of the battery according to Embodiment 1. [Figure 3] It is a cross-sectional view of the battery of FIG. 1 seen in the direction of the arrow III-III. [Figure 4] It is a cross-sectional view of the electrode body of FIG. 3 seen in the direction of the arrow IV-IV. [Figure 5] It is a cross-sectional view of the electrode body of FIG. 3 seen in the direction of the arrow V-V. [Figure 6] It is a schematic cross-sectional view of the electrode body of FIG. 3 partially seen in the direction of the arrow VI-VI. [Figure 7] It is a developed view of the first electrode. [Figure 8]It is a partial cross-sectional view showing an enlarged area VIII of the first electrode in FIG. 5. [Figure 9] It is a partial cross-sectional view showing an enlarged area IX of the electrode body in FIG. 5. [Figure 10] It is a view of the electrode body as seen from the side in the extending direction together with the bottom insulating portion. [Figure 11] It is a partial cross-sectional view of the battery according to the modified example. [Figure 12] It is a developed view of the first electrode in the modified example. [Figure 13] It is a partial cross-sectional view of the electrode body of the battery according to Embodiment 2. [Figure 14] It is a partial cross-sectional view of the electrode body of the battery according to Embodiment 3.

Mode for Carrying Out the Invention

[0020] The current collector and the battery according to each 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.

[0021] (Embodiment 1) 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 capable of charge and discharge, 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.

[0022] Figure 2 is an exploded perspective view of the battery according to Embodiment 1. Figure 3 is a cross-sectional view of the battery in Figure 1, viewed in the direction of the arrow III-III. As shown in Figures 1 to 3, the battery 1 according to Embodiment 1 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, a second connecting member 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.

[0023] Case 20 is conductive. The conductive portion of Case 20 is made of a metal such as aluminum. Case 20 houses the electrode body 10. Case 20 also houses an electrolyte solution, which is not shown in the diagram.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The lid 22 includes a lid body 22a, a sealing plug 22b, a plug cover 22c, and an insulating cover 22d.

[0028] 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.

[0029] 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.

[0030] The first external terminal 30A and the second external terminal 30B are provided so as to be exposed to the outside in the battery 1. The first connecting member 40A and the second connecting member 40B are conductive. At least a portion of the first connecting member 40A and the second connecting member 40B are located inside the case 20.

[0031] The first external terminal 30A or the first connecting member 40A is inserted through the first connecting hole 22aa. 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. As a result, the first external terminal 30A is electrically connected to the electrode body 10.

[0032] The second external terminal 30B or the second connecting member 40B is inserted through the second connecting hole 22ab. 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. As a result, the second external terminal 30B is electrically connected to the electrode body 10.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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, and a bottom insulating portion 73.

[0038] 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.

[0039] The circumferential insulating portion 72 is positioned between the electrode body 10 and the circumferential wall 21b. The electrode body 10 is made of a film-like material.

[0040] 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. In this embodiment, the bottom insulating portion 73 is adhered to the electrode body 10. Furthermore, the bottom insulating portion 73 covers only a portion of the bottom surface of the electrode body 10. The detailed configuration of the bottom insulating portion 73 will be described below together with the configuration of the electrode body 10.

[0041] 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 they are fixed to each other. In this embodiment, the insulating member 70 also includes a plurality of bottom insulating portions 73 so as to correspond one-to-one with the plurality of electrode bodies 10.

[0042] 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.

[0043] 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, a separator 12, and a tape member 13. 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 and Figure 11 described later, the separator 12 is schematically shown by a dashed line.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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).

[0049] The first electrode 11A includes a first current collector 100A, a first active material layer 200A, a first protective section 300, and a second protective section 400.

[0050] Figure 7 is an unfolded view of the first electrode. That is, Figure 7 shows the state before the first electrode 11A is wound. Figure 8 is a partial cross-sectional view showing an enlarged view of region VIII of the first electrode in Figure 5. Figure 9 is a partial cross-sectional view showing an enlarged view of region IX of the electrode body in Figure 5. As shown in Figures 5 to 9, the first current collector 100A includes a support portion 110, a first conductive layer 120, a second conductive layer 130, and a plurality of first tabs 150A.

[0051] 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.

[0052] The support portion 110 includes a support layer 111 and an extension portion 112. The orthogonal direction DO, which is perpendicular to the thickness direction DT of the support layer 111, is approximately parallel to the first direction D1. That is, the support layer 111 extends approximately parallel to the first direction D1.

[0053] The extension portion 112 extends from the support layer 111 in the orthogonal direction DO (see Figure 9). The extension portion 112 extends from the support layer 111 along the first direction D1. More specifically, the extension portion 112 extends downward from the underside of the support layer 111. The extension portion 112 is curved in at least one direction of the thickness direction DT. Specifically, the extension portion 112 is curved toward the winding axis Z. However, the extension portion 112 may also be curved in the direction opposite to the winding axis Z. Furthermore, the extension portion 112 may extend so as to be folded multiple times in both one and the other direction of the thickness direction DT. As a result, the extension portion 112 may overlap in the orthogonal direction DO. The extension portion 112 is formed from a member integral with the support layer 111.

[0054] Furthermore, the extension portion 112 extends over the entire length of the first electrode 11A (first current collector 100A) in the winding direction DR of the electrode body 10 (see Figure 7).

[0055] The thickness of the extension portion 112 may be greater than the thickness of the support layer 111. This improves the strength of the extension portion 112 and suppresses damage to the extension portion 112 when bent. The extension portion 112 may be formed from a material having higher rigidity than the support layer 111.

[0056] 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.

[0057] The first conductive layer 120 is in contact with the support layer 111 on one side in the thickness direction DT. In this embodiment, the first conductive layer 120 is located on the side of the winding axis Z when viewed from the support layer 111. Furthermore, the first conductive layer 120 is in contact with the support layer 111 over its entire surface on one side in the thickness direction DT.

[0058] The second conductive layer 130 is in contact with the support layer 111 on the other side in the thickness direction DT. In this embodiment, the second conductive layer 130 is located on the side opposite to the winding axis Z when viewed from the support layer 111. Furthermore, the second conductive layer 130 is in contact with the support layer 111 over its entire surface on the other side in the thickness direction DT.

[0059] The first conductive layer 120 and the second conductive layer 130 are each made of a metal. In this embodiment, the first conductive layer 120 and the second conductive layer 130 are made of a metal containing aluminum. As a result, the first current collector 100A can be suitably used as a positive electrode current collector. The first current collector 100A may also be a negative electrode current collector, and the first conductive layer 120 and the second conductive layer 130 may be made of a metal containing copper.

[0060] The thickness of the first conductive layer 120 and the thickness of the second conductive layer 130 are thinner than the thickness of the support portion 110. The thickness of the first conductive layer 120 and the second conductive layer 130 is, for example, 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less, in order to reduce the overall thickness of the electrode body 10. The thickness of the first conductive layer 120 and the second conductive layer 130 may be, for example, 0.1 μm or more, in order to prevent the electrical resistance of the first conductive layer 120 and the second conductive layer 130 from becoming too high.

[0061] The first conductive layer 120 and the second conductive layer 130 are provided, for example, by depositing a metal containing aluminum onto the support layer 111. The first conductive layer 120 and the second conductive layer 130 may each be film-like members bonded to the support layer 111.

[0062] Each of the multiple first tabs 150A is joined to the first conductive layer 120 and the second conductive layer 130, for example, by ultrasonic welding. Each of the multiple first tabs 150A extends from the support portion 110 in the direction opposite to the extension direction DE (see Figure 9) from which the extension portion 112 extends from the support layer 111.

[0063] Multiple first tabs 150A are arranged so as to be aligned with each other in the third direction D3 (see Figure 5). Multiple first tabs 150A are joined to each other, for example by ultrasonic welding. Multiple first tabs 150A are joined to the first connecting member 40A, for example by ultrasonic welding (see Figures 2 and 3).

[0064] As shown in Figure 8, each of the multiple first tabs 150A includes a first foil portion 151 and a second foil portion 152.

[0065] The first foil portion 151 is located on the opposite side of the support portion 110 when viewed from the first conductive layer 120. The first foil portion 151 is joined to the first conductive layer 120. The second foil portion 152 is located on the opposite side of the support portion 110 when viewed from the second conductive layer 130. The second foil portion 152 is joined to the second conductive layer 130. On the opposite side of the extension portion 112 when viewed from the support layer 111, the second foil portion 152 is joined to the first foil portion 151. These components are joined to each other, for example, by ultrasonic welding.

[0066] In this embodiment, the length of the first foil portion 151 in the orthogonal direction DO, perpendicular to the thickness direction DT, is longer than the length of the second foil portion 152 in the orthogonal direction DO. The first foil portion 151 is joined to the first connecting member 40A, while the second foil portion 152 is not joined to the first connecting member 40A. However, the configuration of the first tab 150A is not limited thereto. The first foil portion 151 or the second foil portion 152 may be joined to the first connecting member 40A. The length of the second foil portion 152 in the orthogonal direction DO may be longer than the length of the first foil portion 151 in the orthogonal direction DO.

[0067] The first active material layer 200A is laminated on the first conductive layer 120. 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 130. 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 120. The first outer active material layer 220A is laminated on the second conductive layer 130.

[0068] The upper edge of the first active material layer 200A is separated from each of the multiple first tabs 150A. The upper edge of the first inner active material layer 210A is separated from each of the first foil portions 151 of the multiple first tabs 150A. The upper edge of the first outer active material layer 220A is separated from each of the second foil portions 152 of the multiple first tabs 150A.

[0069] As shown in Figure 9, the lower edge of the first active material layer 200A is aligned with the lower edge of the support layer 111. In other words, the lower edge of the first active material layer 200A is aligned with the portion of the extension 112 that extends from the support layer 111.

[0070] Furthermore, the separator 12 is laminated on the first active material layer 200A in the radial direction centered on the winding axis Z. 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.

[0071] The first protective part 300 has electrical insulating properties and is made of, for example, ceramic. The first protective part 300 covers the upper part of the first active material layer 200A. The first protective part 300 further covers the first current collector 100A between the first tab 150A and the first active material layer 200A.

[0072] The first protective section 300 includes a first inner protective section 310 and a first outer protective section 320. The first inner protective section 310 covers the upper part of the first inner active material layer 210A. The first inner protective section 310 covers the first conductive layer 120 between the first foil section 151 and the first inner active material layer 210A. The first outer protective section 320 covers the upper part of the first outer active material layer 220A. The first outer protective section 320 covers the second conductive layer 130 between itself and the first outer active material layer 220A.

[0073] The second protective portion 400 has electrical insulating properties and is made of, for example, ceramic. The second protective portion 400 covers the lower part of the first active material layer 200A. The second protective portion 400 also covers a part of the extension 112.

[0074] The second protective portion 400 includes a second inner protective portion 410 and a second outer protective portion 420. The second inner protective portion 410 covers the lower part of the first inner active material layer 210A. The second inner protective portion 410 further covers a portion of the inner circumferential surface of the extension portion 112 in the radial direction. The second outer protective portion 420 covers the lower part of the first outer active material layer 220A. The second outer protective portion 420 further covers a portion of the outer circumferential surface of the extension portion 112 in the radial direction. The first electrode 11A does not necessarily include the second protective portion 400.

[0075] As shown in Figures 4 to 6 and Figure 9, 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.

[0076] 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 second tabs 150B (see Figure 6). The conductive support portion 140 extends along the orthogonal direction DO (first direction D1). The plurality of second tabs 150B extend from the upper end of the conductive support portion 140. The plurality of second tabs 150B are joined to each other by ultrasonic welding and are also joined to the second connecting member 40B (see Figures 2 and 3).

[0077] The multiple second tabs 150B and conductive support portion 140 are made of a single integrated material, for example, metal foil. In this embodiment, the multiple second tabs 150B 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, the multiple second tabs 150B and conductive support portion 140 may be made of a metal including aluminum.

[0078] 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. Also, as shown in Figure 9, the edge of the second active material layer 200B in the extension direction DE is located ahead of the edge of the first active material layer 200A. Thus, the edge of the second electrode 11B in the extension direction DE is located ahead of the edges of the first conductive layer 120, the second conductive layer 130, and the first active material layer 200A. The second active material layer 200B may also be the positive electrode active material layer.

[0079] Here, we will further explain the extension portion 112 of the support portion 110 in the first current collector 100A of the first electrode 11A.

[0080] The extension portion 112 extends beyond the second electrode 11B in the extension direction DE from the support layer 111. Furthermore, the extension portion 112 extends beyond the separator 12 in the extension direction DE.

[0081] Furthermore, the extension portion 112 is bent in at least one direction in the thickness direction DT, so that in the extension direction DE from the support layer 111, the extension portion 112 is aligned with the separator 12. More specifically, the extension portion 112 is aligned with the second electrode 11B in the extension direction DE.

[0082] Figure 10 is a view of the electrode body together with the bottom insulating portion, seen from the extension direction side. As shown in Figure 10, the extension portion 112 has adjacent portions that overlap each other in the radial direction centered on the winding axis Z.

[0083] Furthermore, as shown in Figures 5 and 10, the bottom insulating portion 73 is positioned on the outer circumference of the extension portion 112 in the radial direction centered on the winding axis Z, when viewed from the extension direction DE of the extension portion 112. The bottom insulating portion 73 is positioned alongside the first electrode 11A and the second electrode 11B, which are located on the outermost circumference of the electrode body 10.

[0084] As described above, the first current collector 100A according to Embodiment 1 of the present disclosure comprises a support portion 110, a first conductive layer 120, and a second conductive layer 130. The support portion 110 is made of an electrically insulating resin composition. The support portion 110 includes a support layer 111 and an extension portion 112. The first conductive layer 120 is in contact with the support layer 111 on one side in the thickness direction DT of the support layer 111. The second conductive layer 130 is in contact with the support layer 111 on the other side in the thickness direction DT. The extension portion 112 extends from the support layer 111 in an orthogonal direction DO perpendicular to the thickness direction DT.

[0085] According to the above configuration, the extension portion 112 faces a conductive member (for example, the bottom body 21aa of the case 20) located on the side from which the extension portion 112 extends when viewed from the first current collector 100A. This allows the first conductive layer 120 and the second conductive layer 130 to be easily electrically insulated from the conductive member. As a result, on the side from which the extension portion 112 extends, the insulating member (for example, the bottom insulating portion 73) placed between it and the conductive member can be simplified, or the insulating member can be made unnecessary in the battery 1. This allows the volume ratio of the electrode body 10 including the first current collector 100A in the battery 1 to be relatively increased. Therefore, the energy density of the battery 1 can be improved.

[0086] In this embodiment, the extended portion 112 is bent in at least one direction in the thickness direction DT.

[0087] According to the above configuration, on the side where the extension portion 112 extends, the first conductive layer 120 or the second conductive layer 130 can be more reliably electrically insulated from the conductive member.

[0088] A battery 1 according to Embodiment 1 of the present disclosure comprises an electrode body 10 and a case 20. The case 20 is conductive. The case 20 houses the electrode body 10. 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, a first conductive layer 120, and a second conductive layer 130. The support portion 110 is made of an electrically insulating resin composition. The support portion 110 includes a support layer 111 and an extension portion 112. The first conductive layer 120 is in contact with the support layer 111 on one side in the thickness direction DT of the support layer 111. The second conductive layer 130 is in contact with the support layer 111 on the other side in the thickness direction DT. The first active material layer 200A is laminated on the first conductive layer 120. 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 extension portion 112 extends from the support layer 111 in an orthogonal direction DO perpendicular to the thickness direction DT.

[0089] According to the above configuration, the extension portion 112 faces the case 20 (for example, the bottom body 21aa) located on the side from which the extension portion 112 extends when viewed from the first current collector 100A, thereby easily electrically insulating the first conductive layer 120 and the second conductive layer 130 from the conductive member. As a result, on the side from which the extension portion 112 extends, the insulating member (for example, the bottom insulating portion 73) placed between the case 20 and the extension portion 112 can be simplified, or the insulating member can be made unnecessary in the battery 1. This allows the volume ratio of the electrode body 10 including the first current collector 100A in the battery 1 to be increased relatively. Therefore, the energy density of the battery 1 can be improved.

[0090] In this embodiment, the extension portion 112 extends beyond the second electrode 11B in the extension direction DE from the support layer 111.

[0091] With the above configuration, in the extension direction DE, the extension portion 112 comes into contact with the case 20, making it easy to electrically insulate the second electrode 11B from the case 20.

[0092] In this embodiment, the extension portion 112 extends beyond the separator 12 in the extension direction DE.

[0093] With the above configuration, the extension portion 112 can be reliably contacted by the case 20 on the extension direction DE side. Consequently, the electrode body 10 can be electrically insulated from the case 20 even more easily.

[0094] In this embodiment, the extension portion 112 is aligned with the separator 12 in the extension direction DE from the support layer 111.

[0095] With the above configuration, the extension portion 112 can be reliably contacted by the case 20 on the extension direction DE side. Consequently, the electrode body 10 can be electrically insulated from the case 20 even more easily.

[0096] In this embodiment, the extension portion 112 is aligned with the second electrode 11B in the extension direction DE.

[0097] According to the above configuration, the second electrode 11B can be more reliably electrically isolated from the case 20.

[0098] The extension portion 112 does not necessarily have to extend over the entire length of the first electrode 11A (first current collector 100A) in the winding direction DR of the electrode body 10. Figure 11 is a partial cross-sectional view of a modified battery. Figure 12 is an unfolded view of the first electrode in the modified battery. As shown in Figures 11 and 12, the extension portion 112V may be provided only in a portion of the first electrode 11A in the winding direction DR. This region may include the end portion of the winding in the winding direction DR, or it may include the beginning portion of the winding. That is, this region may include the outermost portion of the first electrode 11A with respect to the winding axis Z, or it may include the innermost portion.

[0099] (Embodiment 2) Next, a current collector and battery according to Embodiment 2 of this disclosure will be described. The current collector and battery according to Embodiment 2 differ from those in Embodiment 1 in the configuration of the support portion. The same configuration and effects as in Embodiment 1 will not be repeated in this description.

[0100] Figure 13 is a partial cross-sectional view of the electrode body of the battery according to Embodiment 2. The cross-section shown in Figure 13 corresponds to the cross-section of Embodiment 1 shown in Figure 9.

[0101] As shown in Figure 13, in the support portion 110X according to this embodiment, the support layer 111X includes a first support layer 113 and a second support layer 114. The first support layer 113 and the second support layer 114 are laminated together in the thickness direction DT. The first support layer 113 and the second support layer 114 are formed separately from each other. The first support layer 113 and the second support layer 114 may be formed from the same material or from different materials.

[0102] Furthermore, the extension portion 112X includes a first extension portion 115 and a second extension portion 116. The first extension portion 115 and the second extension portion 116 are aligned with each other in the thickness direction DT. The first extension portion 115 is curved on the opposite side from the second extension portion 116. The second extension portion 116 is curved on the opposite side from the first extension portion 115.

[0103] With the above configuration, both the first conductive layer 120 and the second conductive layer 130 can be more reliably insulated from the conductive member located on the side from which the extension portion 112X extends (for example, the bottom body 21aa of the case 20).

[0104] The first extension portion 115 extends from the first support layer 113. The second extension portion 116 extends from the second support layer 114. The first extension portion 115 and the second extension portion 116 extend beyond the second electrode 11B in the extension direction DE from the first support layer 113 and the second support layer 114, respectively. Furthermore, the first extension portion 115 and the second extension portion 116 extend beyond the separator 12 in the extension direction DE.

[0105] Furthermore, the first extension portion 115 and the second extension portion 116 are bent in opposite directions in the thickness direction DT. As a result, the first extension portion 115 and the second extension portion 116 are aligned with the separators 12 located on both sides in the radial direction in the extension direction DE. More specifically, the first extension portion 115 and the second extension portion 116 are aligned with the second electrodes 11B located on both sides in the radial direction in the extension direction DE.

[0106] (Embodiment 3) Next, a current collector and battery according to Embodiment 3 of this disclosure will be described. The current collector and battery according to Embodiment 3 differ from those of Embodiment 1 in the configuration of the support portion. The same configuration and effects as those of Embodiment 1 will not be repeated in this description.

[0107] Figure 14 is a partial cross-sectional view of the electrode body of the battery according to Embodiment 3. The cross-section shown in Figure 14 corresponds to the cross-section of Embodiment 1 shown in Figure 9.

[0108] As shown in Figure 14, in the support portion 110Y according to this embodiment, a pore 112p is formed in the extension portion 112Y.

[0109] According to the above configuration, the liquid or gas, such as an electrolyte, that is filled into the case 20 can easily spread throughout the entire interior of the case 20 by passing through the pores 112p.

[0110] As described above, the pores 112p specifically impart liquid permeability or gas permeability to the extension portion 112Y in the thickness direction of the extension portion 112Y. The pores 112p are located in a position adjacent to the first electrode 11A in the extension direction DE. The pores 112p are located in a position adjacent to the second electrode 11B in the extension direction DE. The pores 112p are located in a position where the extension portions 112Y overlap each other in the extension direction DE (first direction D1).

[0111] In the above-described embodiment, the combinatable configurations may be combined with each other.

[0112] 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]

[0113] 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 member, 40B Second connecting member, 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 110A First current collector, 110B Second current collector, 110,110X,110Y Support part, 111,111X Support layer, 112,112V,112X,112Y Extension part, 112p Pore, 113 First support layer, 114 Second support layer, 115 First extension part, 116 Second extension part, 120 First conductive layer, 130 Second conductive layer, 140 Conductive support part, 150A First tab, 150B Second tab, 151 First foil part, 152 Second foil part, 200A First active material layer, 200B Second active material layer, 210A First inner active material layer, 220A First outer active material layer, 300 first protective section, 310 first inner protective section, 320 first outer protective section, 400 second protective section, 410 second inner protective section, 420 second outer protective section, 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 First conductive layer and It comprises a second conductive layer, The support portion is made of an electrically insulating resin composition. The support portion includes a support layer and an extension portion. The first conductive layer is in contact with the support layer on one side in the thickness direction of the support layer, The second conductive layer is in contact with the support layer on the other side in the thickness direction, The extension portion is a current collector that extends from the support layer in a direction perpendicular to the thickness direction.

2. The current collector according to claim 1, wherein the extended portion is bent in at least one direction in the thickness direction.

3. The extension includes a first extension and a second extension. The first extension and the second extension are arranged relative to each other in the thickness direction. The first extension is curved on the opposite side from the second extension. The current collector according to claim 1, wherein the second extension is bent to the opposite side from the first extension.

4. The current collector according to any one of claims 1 to 3, wherein a pore is formed in the extension portion.

5. It is a battery, Electrode body and Equipped with a case, The aforementioned case has conductivity, The case houses the electrode body, 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, a first conductive layer, and a second conductive layer. The support portion is made of an electrically insulating resin composition. The support portion includes a support layer and an extension portion. The first conductive layer is in contact with the support layer on one side in the thickness direction of the support layer, The second conductive layer is in contact with the support layer on the other side in the thickness direction, 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 extension portion extends from the support layer in a direction perpendicular to the thickness direction, and the battery.

6. The battery according to claim 5, wherein the extension extends beyond the second electrode in the extension direction from the support layer.

7. The battery according to claim 6, wherein the extension extends beyond the separator in the extension direction.

8. The battery according to claim 5, wherein the extension is bent in at least one direction in the thickness direction.

9. The battery according to claim 8, wherein the extension portion is aligned with the separator in the extension direction from the support layer.

10. The battery according to claim 9, wherein the extension portion is aligned with the second electrode in the extension direction.

11. The extension includes a first extension and a second extension. The first extension and the second extension are arranged relative to each other in the thickness direction. The first extension is curved on the opposite side from the second extension. The battery according to any one of claims 5 to 10, wherein the second extension is curved on the opposite side from the first extension.

12. The battery according to any one of claims 5 to 10, wherein pores are formed in the extension portion.

Images