Composite current collector and battery

Abstract

The utility model provides a composite current collector and a battery, comprising: a support layer, and a first film layer and a second film layer arranged on both sides of the support layer; a through hole is arranged at one end of the support layer; the first film layer and the second film layer can be connected to each other through the through hole. Compared with the traditional structure of welding two metal films together through a welding process, the composite current collector and the battery of the utility model do not have a local strengthening area after welding, the composite current collector is softer, the production process of the pole ear is more stable and convenient, and the space required for the current collector to fold the pole ear is also reduced.

Description

Technical Field

[0001] The present application relates to the technical field of lithium ion batteries, and in particular to a composite current collector and battery for lithium ions. Background Art

[0002] As an important part of electric vehicles, the safety and reliability of secondary batteries are particularly important. The puncture test of secondary batteries is generally risky, so composite current collectors have been developed in the industry. However, conventional composite current collectors usually coat a layer of metal film on the insulating film, and then weld the metals on both sides of the insulating film to their respective thin metals through welding (such as roll welding), and then connect the metal films on both sides; however, welding will increase the thickness of the composite current collector at the welding point, and the welding point is not easy to bend. During the production of the pole ear, the composite current collector needs to set up an additional folding ear space, which leads to a reduction in the overall space utilization of the composite current collector. Utility Model Content

[0003] In order to solve the technical problems of difficult bending and low space utilization of the upper and lower metal film layers in the composite current collector caused by the welding process in the prior art, the utility model provides a composite current collector, including: a support layer, and a first film layer and a second film layer arranged on both sides of the support layer; a through hole is arranged at one end of the support layer; the first film layer and the second film layer can be connected to each other through the through hole.

[0004] Furthermore, the other end of the support layer is also provided with a through hole.

[0005] Furthermore, the through hole is provided in plurality.

[0006] Furthermore, two rows of through holes are formed at the first end of the support layer, and the two rows of through holes are symmetrically arranged.

[0007] Further, the through hole is formed within a range of 50 mm from an end of the supporting layer.

[0008] Furthermore, the through hole is formed in a rectangular shape.

[0009] Furthermore, the support layer is made of insulating material.

[0010] Furthermore, the first film layer is made of metal material.

[0011] Furthermore, the thickness of the first film layer is 0.5 μm-3 μm.

[0012] Another aspect of the utility model provides a composite current collector having the above characteristics.

[0013] Compared with the traditional structure of welding two metal films together through welding technology, the composite current collector of the utility model will not have a local reinforcement area after welding, the composite current collector is softer, the pole ear production process is more stable and convenient, and it can also reduce the space required for the current collector to fold the pole ear. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the composite current collector of the utility model;

[0015] Figure 2 It is a schematic diagram of the decomposition of the composite current collector of the utility model;

[0016] Figure 3 It is a partial cross-sectional view of the composite current collector of the utility model;

[0017] Figure 4 It is a schematic diagram of the support layer in the composite current collector of the utility model. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0019] like Figure 1-4 As shown, a composite current collector 10 provided by the present invention includes a support layer 102 and a first film layer 101 and a second film layer 103 arranged on both sides of the support layer 102. Figure 1As shown, the composite current collector 10 of the utility model has a first end 11 and a second end 12 in the axial direction and a main body 13 arranged between the first end 11 and the second end 12; the main body 13 can be used to support the positive and negative active materials of the battery. Specifically, the support layer 102 also includes a first end 1022 and a second end 1023 and a main body 1024 arranged between the first end 1022 and the second end 1023. The first end 1022 of the support layer 102 is provided with a through hole 1021; the second end 1023 of the support layer 102 is also provided with a through hole 1021. In this embodiment, there are 4 through holes 1021 at the first end, and 4 through holes at the second end; the four through holes 1021 at the first end are formed in two rows in the front-to-back direction, and each row is provided with 2 through holes, and the through holes 1021 in the front and back rows are symmetrically arranged. The through hole 1021 is formed within a range of approximately 50 mm from the first end. This arrangement can maintain the strength of the composite current collector at the end without affecting the conductive performance of the end. In this embodiment, the first through hole 1021 is formed in a rectangular shape. Of course, the first through hole can also be configured as a circle or other shapes. The first film layer 101 and the second film layer 103 in the first end 11 and the second end 12 of the utility model can be connected to each other through the through hole 1021.

[0020] In this embodiment, the support layer 102 preferably adopts a high molecular polymer, and the thickness is preferably 4-6um, usually an insulating material such as PP, PET, etc. The first film layer 101 is connected to the support layer 102 by electroplating, electrodeposition, etc. In this embodiment, the support layer 102 provides a skeleton support function, which plays a decisive role in the physical and mechanical properties such as tensile strength and elongation of the composite current collector 10. The first film layer 101 is formed on the support layer 102, and the second film layer is formed below the support layer 102. The first film layer 101 and the second film layer 102 play a role in current collection, which is the main part of the composite current collector, and determines the conductive properties of the composite current collector. When the composite current collector of the utility model is used as a negative electrode material of a battery, the first film layer is formed as a copper layer; when the composite current collector of the utility model is used as a positive electrode material of a battery, the second film layer in this embodiment can be formed as an aluminum layer. The material of the first film layer can be flexibly selected according to the use occasion of the composite current collector and is not limited to copper or aluminum, and can also be formed as other metal materials or conductive materials. However, in order to improve the space utilization of the composite current collector, the utility model preferably sets the thickness of the first film layer within the range of 0.5-3 μm to ensure that the composite current collector has good conductivity without increasing the thickness of the composite current collector, thereby improving the space utilization of the composite current collector in the battery.

[0021] like Figure 3As shown, the composite current collector of the utility model is arranged with multiple through holes 1021 and the support layer material 102 at the axial end, so that the first film layer 101 and the second film layer 103 can be contacted and connected at the end of the composite current collector through the multiple through holes 1021. The arrangement of the multiple through holes 1021 can increase the contact area between the first film layer 101 and the second film layer 103, and improve the contact stability between the first film layer 101 and the second film layer 103. At the same time, the support layer 102 is also arranged between the multiple through holes 1021, and the support layer 102 can increase the mechanical properties and support strength of the composite current collector at the two axial ends. In this embodiment, in the first end provided with the through hole, the area ratio between the through hole and the support layer is preferably 1 / 3, and such an arrangement can ensure good electrical conductivity and mechanical properties at the end of the composite current collector.

[0022] like Figure 3 As shown, the composite current collector of the utility model forms a pole ear in one piece at the axial end. Specifically, the first film layer 101 and the second film layer 101 can pass through the through hole 1021 in the support layer 102 to be connected. Since the first thin layer 101 and the second film layer 101 are formed of metal, an electrical connection can be formed when the first film layer and the second film layer are in contact. The first film layer and the second film layer are connected by chemical plating or electrodeposition. The two film layers are directly formed, and the connection is softer. There is no problem of a strengthening zone in the welding area because the first film layer and the second film layer are connected by welding in the prior art. In addition, in the subsequent production process of the pole ear, the space for folding the pole ear can be reduced. The battery made of the composite current collector of the utility model can improve the safety performance and space utilization of the battery.

[0023] Obviously, the above embodiments of the present invention are only examples for the purpose of clearly explaining the present invention.

[0024] It is not a limitation of the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. A composite current collector, characterized in that: include: A support layer, and a first film layer and a second film layer disposed on both sides of the support layer; A through hole is disposed at one end of the support layer; the first film layer and the second film layer can be connected to each other through the through hole.

2. The composite current collector according to claim 1, characterized in that: The other end of the supporting layer is also provided with a through hole.

3. The composite current collector according to claim 1, characterized in that: The through holes are arranged in plurality.

4. The composite current collector according to claim 3, characterized in that: Two rows of through holes are formed at the first end of the support layer, and the two rows of through holes are symmetrically arranged.

5. The composite current collector according to claim 1, characterized in that: The through hole is formed within a range of 50 mm from an end of the supporting layer.

6. The composite current collector according to claim 1, characterized in that: The through hole is formed in a rectangular shape.

7. The composite current collector according to claim 1, characterized in that: The supporting layer is made of insulating material.

8. The composite current collector according to claim 1, characterized in that: The first film layer is made of metal material.

9. The composite current collector according to claim 1, characterized in that: The thickness of the first film layer is 0.5-3 μm.

10. A battery, characterized in that: It comprises a composite current collector as described in any one of claims 1 to 9.

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