Current collector and battery

Abstract

The invention relates to a current collector and a battery. The current collector is provided with a laminate and a conductive member. The laminate includes a support layer, a first conductive layer, and a second conductive layer. The support layer is configured from a resin composition having electrical insulating properties. The conductive member is disposed on an end edge of the laminated body. The conductive member is bonded to both the first conductive layer and the second conductive layer.

Description

Technical Field

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

[0002] An electrode plate is disclosed in Japanese Patent Application Publication No. 2024-510696. The electrode plate includes a current collector, an active material layer, and an electrical connection member. The current collector includes a support layer and a conductive layer. The support layer is made of an electrically insulating material. The conductive layer is disposed on one surface of the support layer. The electrical connection member and the current collector are welded together at the edge of the current collector. Summary of the Invention

[0003] Current collectors sometimes have two or more conductive layers. Furthermore, when a conductive path is established from one conductive layer to another, consider: first, attaching electrical connection members (tabs) to each of these conductive layers; second, further attaching these tabs. However, such a conductive path from one conductive layer to another is relatively long. Therefore, this conductive path increases the resistance of the current collector, making it prone to overheating when conducting.

[0004] This disclosure was made in view of the above-mentioned problems, and its purpose is to provide a current collector and a battery capable of suppressing heat generation during conduction.

[0005] According to one aspect of this disclosure, a current collector includes a laminate and a conductive member. The laminate includes a support layer, a first conductive layer, and a second conductive layer. The support layer is composed of an electrically insulating resin composition. The conductive member is disposed on an end edge of the laminate. The conductive member is bonded to both the first and second conductive layers.

[0006] A battery according to one aspect of this disclosure includes an electrode body and external terminals. The electrode body includes a first electrode, a second electrode, and a separator. The first electrode includes a current collector and an active material layer. The current collector includes a laminate and a conductive member. The laminate includes a support layer, a first conductive layer, and a second conductive layer. The support layer is composed of a resin composition having electrical insulating properties. The conductive member is disposed on an end edge of the laminate. The conductive member is bonded to both the first and second conductive layers. The active material layer is laminated on the first conductive layer. The separator is laminated on the active material layer. The second electrode is laminated on the active material layer through the separator. The external terminals are electrically connected to the first conductive layer.

[0007] According to this disclosure, it is possible to suppress heat generation when energized. Attached Figure Description

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

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

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

[0011] Figure 3 This is a developed view of the first electrode in one embodiment; and

[0012] Figure 4 It is observed along the direction of the arrow on line IV-IV. Figure 3 A partial cross-sectional view obtained from the first electrode. Detailed Implementation

[0013] Hereinafter, a current collector and a battery according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. The same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0014] Figure 1 This is a cross-sectional view showing one embodiment of a battery. Figure 1 The battery 1 shown is a so-called square battery. Battery 1 can be a rechargeable secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery. Battery 1 can be used, for example, as a battery cell included in an energy storage module mounted in an electric vehicle.

[0015] like Figure 1 As shown, a battery 1 according to one embodiment of the present disclosure includes an electrode body 10, a housing 20, a first external terminal 30A, a second external terminal 30B, a first connecting member 40A, and a second connecting member 40B. First, the structure of the battery 1 excluding the electrode body 10 will be described.

[0016] The housing 20 is conductive. The conductive parts of the housing 20 are made of a metal such as aluminum. The housing 20 houses the electrode body 10. The housing 20 also houses an electrolyte (not shown in the figure).

[0017] The housing 20 includes a housing body 21 and a cover 22. The housing body 21 includes a bottom wall 21a and a peripheral wall 21b rising from the bottom wall 21a.

[0018] The cover 22 is joined to the peripheral wall 21b by welding or the like to close the opening of the peripheral wall 21b. The cover 22 has a first connecting hole 22a and a second connecting hole 22b.

[0019] The first external terminal 30A and the second external terminal 30B are arranged to be exposed to the outside in the battery 1. The first connecting structural member 40A and the second connecting structural member 40B are conductive. At least a portion of the first connecting structural member 40A and the second connecting structural member 40B is disposed inside the housing 20.

[0020] The first external terminal 30A or the first connecting member 40A passes through the first connecting hole 22a. The first external terminal 30A is electrically connected to the first connecting member 40A. Specifically, the first external terminal 30A and the first connecting member 40A are engaged with each other. The first connecting member 40A is engaged with the electrode body 10. Thus, the first external terminal 30A is electrically connected to the electrode body 10.

[0021] The second external terminal 30B or the second connecting member 40B passes through the second connecting hole 22b. The second external terminal 30B is electrically connected to the second connecting member 40B. Specifically, the second external terminal 30B and the second connecting member 40B are engaged with each other. The second connecting member 40B is engaged with the electrode body 10. Thus, the second external terminal 30B is electrically connected to the electrode body 10.

[0022] It should be noted that in this embodiment, the first external terminal 30A is the positive terminal and the second external terminal 30B is the negative terminal. The first external terminal 30A and the second external terminal 30B are arranged in the second direction D2. The second direction D2 is a direction orthogonal to the first direction D1.

[0023] Next, the electrode bodies 10 will be described. The battery 1 of this embodiment includes a plurality of electrode bodies 10. Typically, the battery 1 includes two electrode bodies 10. These electrode bodies 10 are arranged in a third direction D3. The third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2.

[0024] The following description focuses on one of the plurality of electrode bodies 10. It should be noted that the plurality of electrode bodies 10 may also each have the structure shown below.

[0025] Figure 2 It is observed along the direction of the arrow on line II-II. Figure 1 A cross-sectional view obtained from the electrode body. For example... Figure 1 and Figure 2 As shown, the electrode body 10 includes a first electrode 11A, a second electrode 11B, and a spacer 12. The electrode body 10 is wound around the first electrode 11A, the second electrode 11B, and the spacer 12 in a manner that surrounds 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 be a stacked electrode body in which the first electrode 11A, the second electrode 11B, and the spacer 12 are stacked in one direction (e.g., the third direction D3). It should be noted that in Figure 2 In the middle, the separator 12 is schematically represented by a dashed line.

[0026] The first electrode 11A and the second electrode 11B have a sheet-like shape. The electrode body 10 is composed of an electrode plate assembly, which is formed by winding the first electrode 11A and the second electrode 11B with one or more spacers 12 between them. In this embodiment, the first electrode 11A is the positive electrode and the second electrode 11B is the negative electrode. However, it is also possible for the first electrode 11A to be the negative electrode and the second electrode 11B to be the positive electrode.

[0027] A separator 12 is disposed between the first electrode 11A and the second electrode 11B. The separator 12 allows ions to move between the first electrode 11A and the second electrode 11B, and separates the first electrode 11A and the second electrode 11B. The ions are, for example, lithium ions. The separator 12 is electrically insulating.

[0028] Figure 3 This is a developed view of the first electrode in one embodiment. That is, in Figure 3 The image shows the state of the first electrode 11A before it is wound. Figure 4 It is observed along the direction of the arrow on line IV-IV. Figure 3 A partial cross-sectional view obtained from the first electrode.

[0029] like Figures 2 to 4 As shown, the first electrode 11A includes a first current collector 100A, a pair of first active material layers 200A, a first protective part 400, and a second protective part 500.

[0030] And, as Figure 4 As shown, the first current collector 100A includes a laminate 110, a conductive member 120, a plurality of first tabs 160, and a plurality of second tabs 170. The laminate 110 includes a support layer 111, a first conductive layer 112, and a second conductive layer 113.

[0031] The support layer 111 is made of an electrically insulating resin composition. Therefore, the first current collector 100A is a composite current collector composed of conductive and electrically insulating components. As a result, compared to the case where the first current collector 100A is entirely made of metal, the first current collector 100A is lighter, and the safety of the battery 1 as a whole is improved.

[0032] The support layer 111 is made of a material with higher rigidity than the separator 12. The support layer 111 is, for example, made of a resin composition comprising a polyamide resin, a polyester resin, or a polyolefin resin. To improve rigidity, the support layer 111 is preferably made of a resin composition comprising a polyester resin. More preferably, the support layer 111 is substantially made of a polyester resin. This polyester resin may, for example, be polyethylene terephthalate (PET). This allows the electrical insulation of the support layer 111 to be maintained and the rigidity of the first current collector 100A to be improved. Furthermore, the support layer 111 can be made relatively thin.

[0033] The thickness direction DT of the support layer 111 is approximately orthogonal to the first direction D1. That is, the support layer 111 extends along the first direction D1.

[0034] To reduce the overall thickness of the electrode body 10, the thickness of the support layer 111 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. The overall thickness of the support layer 111 is not particularly limited as long as it provides the desired rigidity. For example, the thickness of the support layer 111 can be 2 μm or more.

[0035] The first conductive layer 112 is disposed on one side of the support layer 111 in the thickness direction DT. The first conductive layer 112 is stacked on the support layer 111. The first conductive layer 112 may also be stacked over the entire surface of one side of the support layer 111.

[0036] The second conductive layer 113 is disposed on the other side of the support layer 111 in the thickness direction DT. The second conductive layer 113 is stacked on the support layer 111. The second conductive layer 113 may also be stacked over the entire surface of the other side of the support layer 111.

[0037] The first conductive layer 112 and the second conductive layer 113 are made of metal. This metal can include aluminum, copper, or nickel, etc. In this embodiment, the first conductive layer 112 and the second conductive layer 113 are made of a metal containing aluminum. Therefore, the first current collector 100A, having the first conductive layer 112 and the second conductive layer 113, is suitable for use as a positive current collector. The first conductive layer 112 can also be made of substantially only aluminum. It should be noted that the first current collector 100A can also be a negative current collector.

[0038] The thicknesses of the first conductive layer 112 and the second conductive layer 113 are each thinner than the thickness of the support layer 111. To reduce the overall thickness of the electrode body 10, the thicknesses of the first conductive layer 112 and the second conductive layer 113 are, for example, 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. To suppress excessive resistance, the thicknesses of the first conductive layer 112 and the second conductive layer 113 are, for example, 0.1 μm or more. It should be noted that when the thicknesses of the first conductive layer 112 and the second conductive layer 113 are 5 μm or less, it is relatively difficult to directly weld the first conductive layer 112 and the second conductive layer 113 together or to directly join them by ultrasonic welding.

[0039] The method for forming the first conductive layer 112 and the second conductive layer 113 is not particularly limited. Typically, the first conductive layer 112 and the second conductive layer 113 can also be directly disposed on the support layer 111 by sputtering or vapor deposition. The first conductive layer 112 and the second conductive layer 113 can also be made of metal films. In this case, the first conductive layer 112 and the second conductive layer 113 can also be bonded to the support layer 111 by means of a resin adhesive.

[0040] The conductive member 120 is disposed on the end edge 110E of the laminate 110. The end edge 110E is oriented in one of the directions orthogonal to the thickness direction DT. Specifically, the end edge 110E is oriented in one of the first directions D1, and more specifically, the end edge 110E is oriented in the extension direction DE, which will be described later.

[0041] The conductive member 120 is bonded to both the first conductive layer 112 and the second conductive layer 113. Furthermore, the conductive member 120 is also bonded to the support layer 111.

[0042] The conductive member 120 is joined to both the end edge 112E of the first conductive layer 112 and the end edge 113E of the second conductive layer 113. These end edges 112E and 113E face one of the directions orthogonal to the thickness direction DT. Specifically, the end edges 112E and 113E face one of the first directions D1, and more specifically, the end edges 112E and 113E face the extension direction DE, which will be described later. Furthermore, the conductive member 120 is also joined to the end edge 111E of the support layer 111. The conductive member 120 may also be provided at each of the end edges 111E, 112E, and 113E, extending throughout the entire laminate 110 in the winding direction DR. In this embodiment, the end edge 110E of the laminate 110 includes these end edges 111E, 112E, and 113E.

[0043] The conductive component 120 only needs to be conductive, and its material is not particularly limited. The conductive component 120 can be a conductive resin component, a metal component, or carbon, typically a conductive resin component.

[0044] Typically, conductive resin components are formed by curing a conductive resin slurry. The conductive resin slurry comprises a conductive component containing a metal or carbon and an electrically insulating resin component. The metal, as the conductive component, can include, for example, Ag, Cu, or Ni. The carbon, as the conductive component, can include, for example, carbon black, graphite, carbon fibers, carbon nanotubes, or graphene sheets.

[0045] The resin composition (adhesive) is not particularly limited, and examples include polyurethane resin, polyester resin, phenoxy resin, polyamide resin, polyamide-imide resin, polyimide resin, polyurethane resin, acrylic resin, polystyrene, styrene-acrylic resin, styrene-butadiene copolymer, epoxy resin, phenolic resin, polyether resin, polycarbonate resin, alkyd resin, polysulfone resin, polyethersulfone resin, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer, silicone resin, or fluorine resin, etc.

[0046] When the conductive member 120 is a conductive resin member, a conductive resin member can also be formed by impregnating and coating the end edge 110E of the laminate 110 with a conductive slurry and further curing the conductive slurry.

[0047] When the conductive member 120 is a metal member, the metal member may also contain Al, Ag, Cu, or Ni, etc. This metal member may, for example, be deposited on the end edge 111E of the support layer 111 by vapor deposition. When the conductive member 120 is carbon, carbon may be deposited on the end edge 111E by conventionally known coating methods.

[0048] The Young's modulus of the material constituting the conductive member 120 can also be lower than that of the material constituting the support layer 111. This prevents the conductive member 120 from reducing the processability of the first current collector 100A. The processability of the first current collector 100A refers, for example, to the ease of winding.

[0049] like Figure 3 As shown, a plurality of first tabs 160 are arranged in the winding direction DR of the electrode body 10. A plurality of second tabs 170 are arranged in the winding direction DR of the electrode body 10. The plurality of first tabs 160 are separated from each other. The plurality of second tabs 170 are separated from each other. The plurality of second tabs 170 are arranged in a one-to-one correspondence with the plurality of first tabs 160 in the thickness direction DT.

[0050] And, as Figure 2 As shown, a plurality of first electrodes 160 are arranged in the third direction D3. The plurality of first electrodes 160 are joined together by means of ultrasonic bonding or the like. Furthermore, as... Figure 1 As shown, multiple first tabs 160 are joined to the first connecting member 40A via ultrasonic bonding or the like. Thus, the first external terminal 30A is electrically connected to the first tabs 160. Furthermore, the first external terminal 30A is electrically connected to the first conductive layer 112 and the second conductive layer 113. The structures of each of the multiple first tabs 160 and each of the multiple second tabs 170 will be described below.

[0051] The first tab 160 is ultrasonically welded to the surface of the first conductive layer 112 opposite to the support layer 111. The first tab 160 is partially bonded to the first conductive layer 112. The first tab 160 extends substantially along the first direction D1 on the first conductive layer 112. The first tab 160 extends away from the first conductive layer 112. The extension direction DE of the first tab 160 is substantially parallel to the first direction D1. It should be noted that the first tab 160 can also be directly bonded to the first external terminal 30A. In addition, the first tab 160 is in contact with the conductive member 120 in the thickness direction DT.

[0052] The second tab 170 is ultrasonically welded to the surface of the second conductive layer 113 opposite to the support layer 111. The second tab 170 is partially bonded to the second conductive layer 113. The second tab 170 extends on the second conductive layer 113 generally along the first direction D1. The second tab 170 extends along the extension direction DE away from the second conductive layer 113. The end of the second tab 170 in the extension direction DE is ultrasonically bonded to the first tab 160. The extension length of the second tab 170 is shorter than the extension length of the first tab 160. The second tab 170 is in contact with the conductive member 120 in the thickness direction DT.

[0053] The first tab 160 and the second tab 170 are composed of a membrane-like component. The first tab 160 and the second tab 170 are typically composed of a metal membrane containing aluminum or copper, etc.

[0054] The thickness of each of the first tab 160 and the second tab 170 is greater than the thickness of each of the first conductive layer 112 and the second conductive layer 113. The thickness of each of the first tab 160 and the second tab 170 is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less. Their respective thicknesses are not particularly limited as long as they possess the desired rigidity. For example, their respective thicknesses can be 2 μm or more.

[0055] A first active material layer 200A is partially stacked on the first conductive layer 112. Another first active material layer 200A is partially stacked on the second conductive layer 113. These first active material layers 200A are positive electrode active material layers, but they can also be negative electrode active material layers. These first active material layers 200A are separated from the first tab 160 and the second tab 170. The separator 12 is stacked on the first active material layers 200A radially about the winding axis Z.

[0056] The first protective portion 400 is made of electrically insulating ceramic. The first protective portion 400 covers a portion of the first active material layer 200A, which is stacked on the first conductive layer 112, along its extension direction DE. The first protective portion 400 covers the entire surface of the first conductive layer 112 between the first active material layer 200A and the first tab 160. The first protective portion 400 is also partially disposed between the first conductive layer 112 and the first tab 160 in the thickness direction DT.

[0057] The second protective portion 500 is made of electrically insulating ceramic. The second protective portion 500 covers a portion of the first active material layer 200A, which is stacked on the second conductive layer 113, along its extension direction DE. The second protective portion 500 covers the entire surface of the second conductive layer 113 between the first active material layer 200A and the second tab 170. Furthermore, the second protective portion 500 is also partially disposed between the second conductive layer 113 and the second tab 170 along its thickness direction DT.

[0058] like Figure 2 As shown, the second electrode 11B is stacked on the first active material layer 200A in the aforementioned radial direction, separated by the spacer 12. In this embodiment, the electrode body 10 includes a plurality of spacers 12, but may also include a single spacer 12.

[0059] The second electrode 11B includes a second current collector 100B and a second active material layer 200B. The second current collector 100B extends from the middle of the second active material layer 200B towards one side in the first direction D1. The second current collector 100B is joined to the second connecting member 40B by ultrasonic welding (see reference). Figure 1 ).

[0060] The second current collector 100B is, for example, made of a metal film. The second current collector 100B is, for example, made of a metal containing copper. Therefore, the second current collector 100B is suitable for use as a negative current collector. It should be noted that when the first current collector 100A is the negative current collector and the second current collector 100B is the positive current collector, the second current collector 100B may also be made of a metal containing aluminum. Alternatively, the second current collector 100B may have the same structure as the first current collector 100A.

[0061] The second active material layer 200B is stacked on both sides of the second current collector 100B. It should be noted that in this embodiment, the second electrode 11B is the negative electrode. Therefore, the second active material layer 200B is a negative electrode active material layer. It should also be noted that the second active material layer 200B can also be a positive electrode active material layer.

[0062] As described above, a first current collector 100A according to an embodiment of the present disclosure includes a laminate 110 and a conductive member 120. The laminate 110 includes a support layer 111, a first conductive layer 112, and a second conductive layer 113. The support layer 111 is made of a resin composition having electrical insulating properties. The conductive member 120 is disposed on an end edge 110E of the laminate 110. The conductive member 120 is bonded to both the first conductive layer 112 and the second conductive layer 113.

[0063] According to the above structure, the first conductive layer 112 and the second conductive layer 113 can be interconnected via the conductive member 120 disposed on the end edge 110E of the laminate 110 without passing through the tabs stacked on the surfaces of the first conductive layer 112 and the second conductive layer 113. Therefore, the conductive path between the first conductive layer 112 and the second conductive layer 113 becomes shorter. Consequently, the resistance value in this conductive path becomes smaller, which can suppress the heat generation when the first current collector 100A is energized.

[0064] In this embodiment, the first conductive layer 112 is disposed on one side of the support layer 111 in the thickness direction DT. The second conductive layer 113 is disposed on the other side of the support layer 111 in the thickness direction DT. The conductive member 120 is bonded to both the end edge 112E of the first conductive layer 112 and the end edge 113E of the second conductive layer 113.

[0065] According to the above structure, the conductive path between the first conductive layer 112 and the second conductive layer 113 is further shortened. As a result, the resistance value in this conductive path becomes smaller, which can further suppress the heat generation when the first current collector 100A is energized.

[0066] Furthermore, the first current collector 100A in this embodiment also includes a first tab 160 and a second tab 170. The first tab 160 is ultrasonically welded to the surface of the first conductive layer 112. The first tab 160 is in contact with the conductive member 120. The second tab 170 is ultrasonically welded to the surface of the second conductive layer 113. The second tab 170 is ultrasonically welded to the first tab 160. The second tab 170 is in contact with the conductive member 120.

[0067] According to the above structure, in the conductive path between the first conductive layer 112 and the second conductive layer 113, the area of ​​the cross-section of the conductor orthogonal to the conductive path becomes larger. As a result, the resistance value in the conductive path between the first conductive layer 112 and the second conductive layer 113 is further reduced. Furthermore, the heat generation when the first current collector 100A is energized can be further suppressed.

[0068] In this embodiment, the conductive member 120 is a conductive resin member. The conductive resin member is formed by curing a conductive resin slurry. The conductive resin slurry includes a conductive component containing metal or carbon and a resin component having electrical insulating properties.

[0069] According to the above structure, the conductive resin component may soften due to the heat generated during the ultrasonic welding of the first tab 160 and the second tab 170. This suppresses any obstruction to the ultrasonic welding of the first tab 160 and the second tab 170. Furthermore, peeling of the first tab 160 and the second tab 170 can be suppressed. Additionally, the conductive resin component can be more firmly connected to the first tab 160 and the second tab 170.

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

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

Claims

1. A current collector, wherein, This current collector has the following features: Layered bodies; and Conductive components The laminate includes a support layer, a first conductive layer, and a second conductive layer. The support layer is composed of an electrically insulating resin composition. The conductive component is disposed on the end edge of the laminate. The conductive component is bonded to both the first conductive layer and the second conductive layer.

2. The current collector according to claim 1, wherein, The first conductive layer is disposed on one side of the support layer in the thickness direction. The second conductive layer is disposed on the other side of the support layer in the thickness direction. The conductive member is joined to both the end edge of the first conductive layer and the end edge of the second conductive layer.

3. The current collector according to claim 2, wherein, The current collector also has a first tab and a second tab. The first electrode tab is bonded to the surface of the first conductive layer by ultrasonic welding. The first electrode tab is connected to the conductive component. The second electrode tab is bonded to the surface of the second conductive layer by ultrasonic welding. The second electrode tab is joined to the first electrode tab by ultrasonic welding. The second electrode is connected to the conductive component.

4. The current collector according to claim 3, wherein, The conductive component is a conductive resin component, which is formed by curing a conductive resin slurry, the conductive resin slurry comprising a conductive component containing metal or carbon and a resin component having electrical insulating properties.

5. A battery, wherein, This battery has the following features: Electrode body; and external terminals, The electrode body includes a first electrode, a second electrode, and a separator. The first electrode includes a current collector and an active material layer. The current collector includes a laminate and a conductive component. The laminate includes a support layer, a first conductive layer, and a second conductive layer. The support layer is composed of an electrically insulating resin composition. The conductive component is disposed on the end edge of the laminate. The conductive component is bonded to both the first conductive layer and the second conductive layer. The active material layer is stacked on the first conductive layer. The separator is stacked on top of the active material layer. The second electrode is stacked on the active material layer with the separator in between. The external terminal is electrically connected to the first conductive layer.

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