Current collector

Abstract

The utility model provides a current collector which comprises a base film body, a first metal layer and a second metal layer are arranged on the upper surface and the lower surface of the base film body, the base film body comprises a PP layer, non-woven fabric layers are arranged on the upper surface and the lower surface of the PP layer respectively, and each non-woven fabric layer comprises a PET layer. According to the utility model, the binding force between the metal layer and the base film is improved through the non-woven fabric layer, and the cycle life of the battery is effectively prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field, especially a kind of current collector. BACKGROUND

[0002] The positive electrode composite current collector structure on current market is with PET layer as middle layer, and metal aluminum layer is arranged on the upper and lower surfaces of PET layer. And the structure of negative electrode composite current collector is with PP layer as middle layer, and metal copper layer is arranged on the upper and lower layers of PP film.

[0003] But the current negative electrode composite current collector if only uses PP film as middle layer, then the binding force of PP film and the metal layer on its upper and lower sides is not enough, leading to battery failure.

[0004] Therefore, prior art needs to be improved and improved. UTILITY MODEL CONTENT

[0005] In view of the above deficiencies of prior art, the utility model provides a kind of current collector, can improve the binding force of metal layer and base film, effectively improve the cycle life of battery.

[0006] In order to achieve the above purpose, the utility model takes the following technical scheme:

[0007] A kind of current collector, including base film body, the upper surface and lower surface of the base film body are provided with first metal layer and second metal layer, the base film body includes PP layer, the upper surface and lower surface of the PP layer are respectively provided with non-woven fabric layer, the non-woven fabric layer includes PET layer.

[0008] Further, the width of the non-woven fabric layer is greater than the width of the PP layer.

[0009] Further, the pore size of the part of the non-woven fabric layer beyond the PP layer is greater than the pore size of the overlapping part of the non-woven fabric and the PP layer.

[0010] Further, the base film body is provided with aluminum oxide layer, and the aluminum oxide layer is provided with aluminum layer.

[0011] Further, the PP layer contains conductive parts.

[0012] Further, the mass of the conductive part accounts for 10%-20% of the mass of the PP layer.

[0013] Further, the material of the first metal layer and the second metal layer is different.

[0014] Further, the first metal layer is copper layer, and the second metal layer is aluminum layer, and the mass of the first metal layer and the second metal layer is the same.

[0015] Further, any one of a nickel copper layer, a titanium copper layer, a copper alloy layer or an aluminum alloy layer is arranged between the first metal layer and the base film body, and an aluminum oxide layer or a silicon nitride layer is arranged between the second metal layer and the base film body.

[0016] Compared with the prior art, the current collector provided by the utility model, comprising a base film body, the upper surface and the lower surface of the base film body are provided with a first metal layer and a second metal layer, the base film body comprises a PP layer, the upper surface and the lower surface of the PP layer are respectively provided with a non-woven fabric layer, and the non-woven fabric layer comprises a PET layer. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings required to be used in the embodiments or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to the structures shown in these drawings without creative labor.

[0018] Figure 1 The structure diagram of the base film provided by the utility model is shown.

[0019] The drawing mark is explained as follows:

[0020] The base film body-1, the first metal layer-2, the second metal layer-3, the PP layer-4, the non-woven fabric layer-5. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present application, the present application will be more fully described below with reference to the relevant drawings. The drawings show the embodiments of the present application. However, the present application can be realized in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application.

[0023] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "transverse", "longitudinal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to indicating the orientation or positional relationship, the above-mentioned terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific circumstances.

[0024] In addition, the terms "first" and "second" and the like used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. As used herein, the singular forms "a", "an" and "the" can also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "include / contain" or "have" and the like specify the presence of the stated features, integers, steps, operations, components, parts or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts or combinations thereof.

[0025] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there can be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or a middle element can be present. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes.

[0026] In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, also not within the protection scope required by the present application.

[0027] As Figure 1As shown, the current collector provided by this utility model includes a base film body 1. A first metal layer 2 and a second metal layer 3 are disposed on the upper and lower surfaces of the base film body 1. The base film body 1 includes a PP layer 4, and non-woven fabric layers 5 are disposed on the upper and lower surfaces of the PP layer 4, respectively. The non-woven fabric layer 5 includes a PET layer. The non-woven fabric layer 5 has pores. When a metal layer, i.e., a coating, is formed on the base film body 1, the metal layer will bond to the pores on one hand and form on the non-woven fabric layer 5 on the other, effectively increasing the bonding force between the metal layer and the base film body 1. Furthermore, the PP film can prevent the base film body 1 from expanding in the battery electrolyte. Because the non-woven fabric layer 5 has pores and is very thin, the expansion is negligible, which can improve the cycle life of the battery. PET refers to polyethylene terephthalate, a commonly used polymer substrate, and the PP layer refers to polypropylene.

[0028] Compared with the prior art, the technical solution provided by this utility model improves the bonding force between the metal layer and the base film through the non-woven fabric, thereby effectively improving the cycle life of the battery.

[0029] Furthermore, the width of the nonwoven fabric layer 5 is greater than the width of the PP layer 4. In this embodiment, the width of the nonwoven fabric layer 5 is greater than the width of the PP layer 4 in the width direction of the base film, so as to reduce the influence of the PET material on the resistance at the tab welding point during tab welding.

[0030] Furthermore, the pore size of the portion of the nonwoven fabric extending beyond the PP layer 4 is larger than the pore size of the portion of the nonwoven fabric overlapping with the PP layer 4, in order to reduce the influence of the PET material on the resistance at the electrode welding point during electrode welding.

[0031] Furthermore, an aluminum oxide layer is disposed on the base film body 1, and an aluminum layer is disposed on the aluminum oxide layer. In this embodiment, the aluminum oxide layer and the aluminum layer are disposed between the base film body 1 and the first metal layer 2, and between the base film body 1 and the second metal layer 3. The aluminum layer is formed on the film by heating aluminum in a crucible, and the aluminum oxide is formed on the base film body 1 by heating aluminum wire in an evaporation boat, where the aluminum wire evaporates and rises, combining with oxygen. The aluminum oxide layer can increase the bonding force between the metal layer and the PP layer 4.

[0032] Furthermore, the PP layer 4 includes a conductive component, such as a metal or a conductive polymer material. This conductive component reduces the internal resistance of the composite current collector. Preferably, the conductive component accounts for 10%-20% of the mass of the PP layer 4 for better results in reducing internal resistance.

[0033] Furthermore, the first metal layer 2 and the second metal layer 3 are made of different materials. In this embodiment, the first metal layer 2 is a copper layer and the second metal layer 3 is an aluminum layer, which can improve the puncture resistance of the composite current collector.

[0034] Furthermore, the first metal layer 2 and the second metal layer 3 have the same mass, which can prevent the composite current collector from curling.

[0035] Furthermore, a nickel-copper layer, a titanium-copper layer, a copper alloy layer, or an aluminum alloy layer is disposed between the first metal layer 2 and the base film body 1, which can improve the bonding force between the first metal layer 2 and the base film body 1; an aluminum oxide layer or a silicon nitride layer is disposed between the second metal layer 3 and the base film body 1, which can improve the bonding force between the second metal layer 3 and the base film body 1.

[0036] In this embodiment, the composite current collector with a copper layer on one side and an aluminum layer on the other side of the base film body 1 is fabricated as follows: First, the base film body 1 is taken and placed in a vacuum evaporation equipment to deposit aluminum metal onto the base film body 1. Then, the aluminum-plated base film body 1 is placed in a magnetron sputtering coating equipment to form metallic copper on the side of the base film body 1 without copper.

[0037] In summary, the current collector provided by this invention features a nonwoven fabric layer with a width greater than that of the PP layer, and the pore size of the portion of the nonwoven fabric extending beyond the PP layer is larger than the pore size of the overlapping portion of the nonwoven fabric and the PP layer. This reduces the impact of the PET material on the resistance at the electrode welding point during tab welding. The alumina layer increases the bonding force between the metal layer and the PP layer. The conductive material accounts for 10%-20% of the mass of the PP layer, further enhancing the effect of reducing internal resistance. This invention improves the bonding force between the metal layer and the base film through the nonwoven fabric layer, effectively increasing the cycle life of the battery.

[0038] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the scope of protection of the present invention.

Claims

1. A current collector, characterized in that, The base film body (1) includes a base film body (1), the upper and lower surfaces of which are provided with a first metal layer (2) and a second metal layer (3), the base film body (1) includes a PP layer (4), the upper and lower surfaces of which are respectively provided with a non-woven fabric layer (5), the non-woven fabric layer (5) including a PET layer.

2. The current collector according to claim 1, characterized in that, The width of the nonwoven fabric layer (5) is greater than the width of the PP layer (4).

3. The current collector according to claim 2, characterized in that, The pore size of the portion of the nonwoven fabric that extends beyond the PP layer (4) is larger than the pore size of the portion of the nonwoven fabric that overlaps with the PP layer (4).

4. The current collector according to claim 1, characterized in that, An aluminum oxide layer is disposed on the base film body (1), and an aluminum layer is disposed on the aluminum oxide layer.

5. The current collector according to claim 1, characterized in that, The PP layer (4) contains conductive elements.

6. The current collector according to claim 5, characterized in that, The mass of the conductive element accounts for 10%-20% of the mass of the PP layer (4).

7. The current collector according to claim 1, characterized in that, The first metal layer (2) and the second metal layer (3) are made of different materials.

8. The current collector according to claim 7, characterized in that, The first metal layer (2) is a copper layer, and the second metal layer (3) is an aluminum layer. The first metal layer (2) and the second metal layer (3) have the same mass.

9. The current collector according to claim 8, characterized in that, The first metal layer (2) and the base film body (1) are provided with any one of a nickel copper layer, a titanium copper layer, a copper alloy layer or an aluminum alloy layer, and the second metal layer (3) and the base film body (1) are provided with an aluminum oxide layer or a silicon nitride layer.

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