Preparation method of composite conductive film, composite conductive film and preparation system

Abstract

The invention provides a preparation method of a composite conductive film. The preparation method comprises the following steps: (S1) providing a porous base material film with a plurality of through holes; (S2) compounding a non-porous sacrificial layer on the first surface of the porous base material film, so that the non-porous sacrificial layer covers the first surface and seals the first end opening of the through hole; (S3) depositing a first metal layer on the exposed second surface of the porous substrate film, wherein the first metal layer covers the second surface and extends to cover the inner wall of the through hole; (S4) removing the non-porous sacrificial layer to expose the first surface of the porous base material film and the first end opening of the through hole; and (S5) depositing a second metal layer on the exposed first surface, wherein the second metal layer covers the first surface and extends to cover the inner wall of the through hole. The composite conductive film prepared by the preparation method has lower internal resistance and higher conductivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a preparation method of a composite conductive film, a composite conductive film and a preparation system. BACKGROUND

[0002] The composite conductive film has flexibility and conductivity, and the conductivity depends on the conductive material on the surface. Generally, the conductive metal material is deposited on both sides of the surface of the non-through hole base film by vacuum plating process, and the middle is not conductive. The through holes of the base film can connect the conductive metal layers on both sides to enhance the conductivity and combination. However, the vacuum deposition of conductive metal material on both sides of the porous base film can only be made on sheet materials at present, and cannot be produced by winding. The winding process has the following three difficulties: 1. The tensile property does not meet the minimum tension of winding, and the film body will be deformed; 2. The plated metal of the porous film will pollute the main drum through the holes; 3. The cooling efficiency of the vacuum plating of the porous base film is low, and the problem of thermal deformation occurs. SUMMARY

[0003] The composite conductive film has flexibility and conductivity, and the conductivity depends on the conductive material on the surface. Generally, the conductive metal material is deposited on both sides of the surface of the non-through hole base film by vacuum plating process, and the middle is not conductive. The through holes of the base film can connect the conductive metal layers on both sides to enhance the conductivity and combination. However, the vacuum deposition of conductive metal material on both sides of the porous base film can only be made on sheet materials at present, and cannot be produced by winding. The winding process has the following three difficulties: 1. The tensile property does not meet the minimum tension of winding, and the film body will be deformed; 2. The plated metal of the porous film will pollute the main drum through the holes; 3. The cooling efficiency of the vacuum plating of the porous base film is low, and the problem of thermal deformation occurs. SUMMARY

[0004] In view of the above technical problems of the prior art, the present application provides a preparation method of a composite conductive film to solve the technical problem that the vacuum deposition of conductive metal material on both sides of the porous base film can only be made on sheet materials at present, and cannot be produced by winding.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: A method for preparing a composite conductive film, comprising the following steps: (S1) providing a porous substrate film having a plurality of through-holes; (S2) compounding a non-porous sacrificial layer on a first surface of the porous substrate film, so that the non-porous sacrificial layer covers the first surface and seals first end openings of the through-holes; (S3) depositing a first metal layer on an exposed second surface of the porous substrate film, the first metal layer covering the second surface and extending to cover inner walls of the through-holes; (S4) removing the non-porous sacrificial layer to expose the first surface of the porous substrate film and the first end openings of the through-holes; (S5) depositing a second metal layer on the exposed first surface, the second metal layer covering the first surface and extending to cover the inner walls of the through-holes, and forming a continuous conductive path with the first metal layer in the through-holes; wherein the first metal layer and the second metal layer together constitute a double-sided metallized composite conductive film penetrating through the porous substrate film.

[0006] Further, the porous substrate film having a plurality of through-holes in step (S1) can be a finished substrate film with holes or a porous substrate film having a plurality of through-holes formed on a non-porous substrate film by laser drilling, mechanical punching or chemical etching.

[0007] Further, in the step (S2), the compounding is achieved by hot-press compounding, adhesive compounding or melt lamination.

[0008] Further, in the step (S4), the removing is achieved by dissolution peeling, thermal decomposition peeling or mechanical peeling.

[0009] Further, the porous substrate film is a polyimide film, a polyester film, a polyolefin microporous film or an aramid fiber film.

[0010] In another aspect, the present application also provides a composite conductive film prepared according to the method for preparing a composite conductive film, comprising: a porous substrate film having a plurality of through-holes; a first metal layer covering a second surface of the porous substrate film; a second metal layer covering a first surface of the porous substrate film; wherein the first metal layer and the second metal layer form a three-dimensional interconnected conductive network through a metal conductive layer covering inner walls of the through-holes.

[0011] Further, the material of the first metal layer and the second metal layer is independently selected from copper, aluminum, nickel or alloys thereof.

[0012] In another aspect, the present application also provides a preparation system for preparing the composite conductive film, comprising: a punching device for forming through holes on a porous substrate film; a compounding device for compounding a non-porous sacrificial layer on a first surface of the porous substrate film; a first plating device for depositing a first metal layer on a second surface of the porous substrate film; a stripping device for removing the non-porous sacrificial layer; a second plating device for depositing a second metal layer on the exposed first surface; and a conveying mechanism for sequentially conveying the substrate to each device; wherein the compounding device is located downstream of the punching device, and the stripping device is located between the first plating device and the second plating device.

[0013] Further, the first plating device and the second plating device are independently a vacuum evaporation cabin, a magnetron sputtering cabin or a chemical plating tank.

[0014] Compared with the prior art, the preparation method of the composite conductive film of the present application comprises the following steps: (S1) providing a porous substrate film having a plurality of through holes; (S2) compounding a non-porous sacrificial layer on a first surface of the porous substrate film, so that the non-porous sacrificial layer covers the first surface and closes the first end opening of the through holes; (S3) depositing a first metal layer on the exposed second surface of the porous substrate film, the first metal layer covering the second surface and extending to cover the inner wall of the through holes; (S4) removing the non-porous sacrificial layer to expose the first surface of the porous substrate film and the first end opening of the through holes; (S5) depositing a second metal layer on the exposed first surface, the second metal layer covering the first surface and extending to cover the inner wall of the through holes, and forming a continuous conductive path with the first metal layer in the through holes; wherein the first metal layer and the second metal layer together constitute a double-sided metallized composite conductive film penetrating through the porous substrate film. Through the above preparation method, the winding mass production plating of the porous substrate film can be realized, and the existence of the non-porous sacrificial layer solves the problem of main drum pollution in the process of making the porous substrate film. The composite conductive film prepared by the above preparation method has lower internal resistance and higher conductivity, which can reduce the overcurrent heating of the tab in the battery. The composite conductive film can be compatible with ultrasonic spot welding, roll welding, pressure fusion welding and other welding processes. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The flowchart of the preparation method of the composite conductive film provided by the present application; Figure 2 The structure diagram of the composite conductive film provided by the present application. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and effect of the present application clearer and more explicit, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only intended to explain the present application and not to limit the present application.

[0017] It should be noted that when a component is referred to as "mounted on", "fixed on" or "provided on" another component, it can be directly on the other component or a middle component can be present at the same time. When a component is referred to as "connected to" another component, it can be directly connected to the other component or a middle component can be present at the same time.

[0018] It should also be noted that the left, right, up, down and other orientation terms in the embodiments of the present application are only relative concepts or are referenced to the normal use state of the product, and should not be considered as limiting.

[0019] Currently, vacuum deposition of conductive metal material on both sides of the porous substrate film can only be made on sheet materials, and cannot be made by winding mass production. The winding process has the following three difficulties: 1. The tensile properties do not meet the minimum tension of winding, and the film body will be deformed; 2. The porous film plating will have the risk of main drum pollution by plated metal penetrating the holes; 3. The problem of low cooling efficiency and thermal deformation of the porous substrate film vacuum plating. In view of the above problems, the inventors propose a preparation method of a composite conductive film, as shown in Figure 1 The preparation method of the composite conductive film includes a step (S1), which is: providing a porous substrate film having a plurality of through holes; "providing a porous substrate film having a plurality of through holes" means obtaining a porous substrate film having a plurality of through holes as a raw material for producing the composite current collector. The porous substrate film serves as a support layer of the composite conductive film, which on the one hand reduces the mass of the traditional pure metal conductive film, and on the other hand, with the support layer of the composite conductive film, the metal burr generated when the composite conductive film is punctured can also be reduced. The porous substrate film can be one or more of polyimide film, polyester film, polyolefin microporous film or aramid fiber film.

[0020] Further, the preparation method of the composite conductive film further includes a step (S2), which is: compounding a non-porous sacrificial layer on a first surface of the porous substrate film, so that the non-porous sacrificial layer covers the first surface and seals the first end opening of the through hole; simply speaking, the purpose of the step (S2) is to form a non-porous sacrificial layer on one surface of the porous substrate film. The method can be a hot pressing compounding process, such as dry compounding, wet compounding, extrusion compounding and co-extrusion compounding, or can be adhesive compounding or melt lamination, etc. Of course, it can also be other processes, as long as the porous substrate film and the non-porous sacrificial layer can be combined together, any process can be used.

[0021] Further, the preparation method of the composite conductive film further comprises a step (S3) of depositing a first metal layer on the exposed second surface of the porous substrate film, the first metal layer covering the second surface and extending to cover the inner wall of the through hole; the step (S3) means that the first metal layer is deposited on the side of the porous substrate film which is not in contact with the non-porous sacrificial layer. Since the porous substrate film has holes, the holes of the porous substrate film are exposed to the vacuum plating environment, so that the metal vapor generated in the vacuum plating process enters the holes of the porous substrate film, that is, fills the holes of the porous substrate film, and at the same time forms on the surface of the porous substrate film, thereby forming the first metal layer. In this way, since the first metal layer penetrates into the interior of the porous substrate film, the metal of the first metal layer is tightly combined with the porous substrate film, thereby improving the bonding force between the metal layer and the porous substrate film.

[0022] Further, the preparation method of the composite conductive film further comprises a step (S4) of removing the non-porous sacrificial layer to expose the first surface of the porous substrate film and the first end opening of the through hole; the purpose of the step (S4) is to remove the non-porous sacrificial layer from the porous substrate film, so that the side of the porous substrate film which does not form a metal layer is exposed, and is ready for the next plating. In this way, the non-porous sacrificial layer can be recycled, thereby reducing the cost. In the step (S4), the non-porous sacrificial layer can be removed from the porous substrate film by means of dissolution peeling, thermal decomposition peeling or mechanical peeling.

[0023] Further, the preparation method of the composite conductive film further comprises a step (S5) of depositing a second metal layer on the exposed first surface, the second metal layer covering the first surface and extending to cover the inner wall of the through hole, and forming a continuous conductive path with the first metal layer in the through hole; wherein the first metal layer and the second metal layer together constitute a double-sided metallized composite conductive film penetrating through the porous substrate film. The purpose of the step (S5) is to form a second metal layer on the surface of the porous substrate film which does not form a metal layer. Since the first metal layer has been formed and penetrates into the interior of the porous substrate film, the first metal layer and the second metal layer can be in contact with each other, thereby reducing the internal resistance of the composite conductive film. Moreover, since the holes of the porous substrate film may not be filled with the first metal layer, the second metal layer can also fill the holes of the porous substrate film, thereby further reducing the internal resistance of the composite conductive film.

[0024] On the other hand, the present application also provides a composite conductive film prepared according to the preparation method of the composite conductive film, which comprises Figure 2As shown, the composite conductive film comprises: a porous substrate film 3 with a plurality of through holes; a first metal layer 2 covering the second surface 5 of the porous substrate film 3; a second metal layer 1 covering the first surface 4 of the porous substrate film; wherein the first metal layer 1 and the second metal layer 2 form a three-dimensional interlinked conductive network by covering the inner wall of the through hole with a metal conductive layer. The composite conductive film has the above structure, which greatly reduces its internal resistance, and because the metal layer is embedded in the interior of the composite conductive film, not only can the internal resistance be reduced, but also the strength of the composite conductive film can be improved while improving the bonding strength of the metal layer and the porous substrate film of the composite conductive film. Preferably, the material of the first metal layer 2 and the second metal layer 1 can be independently selected from copper, aluminum, nickel or alloys thereof.

[0025] On the other hand, the present application also provides a preparation system for preparing the composite conductive film, comprising: a punching device for forming through holes on the porous substrate film; preferably, the punching device can be a laser punching device, a mechanical punching device or a chemical etching device. Here, the punching device is not limited, because it is an existing device, and as long as it can punch the porous substrate film.

[0026] Further, the preparation system of the composite conductive film further comprises a device for compounding a non-porous sacrificial layer on the first surface of the porous substrate film; here, the non-porous sacrificial layer can increase the strength of the porous substrate film, prevent the porous substrate film from being scalded by high temperature and causing curling and other defects, and prevent the existence of through holes from causing pollution to the main drum during the plating process. Similarly, dry compounding machines, wet compounding machines, extrusion compounding machines and co-extrusion compounding machines can be used to set the non-porous sacrificial layer on the porous substrate film, or adhesive compounding machines or melt lamination machines, etc., which are all known machines and equipment.

[0027] Further, the preparation system of the composite conductive film further comprises a first plating device for depositing a first metal layer on the second surface of the porous substrate film; the first plating device can be a magnetron sputtering device, a vacuum evaporation device, etc., which are all known devices.

[0028] Further, the preparation system of the composite conductive film further comprises a stripping device for removing the non-porous sacrificial layer; the stripping device is used to strip the non-porous sacrificial layer from the porous substrate film, and after stripping, a second metal layer can be formed on the surface of the porous substrate film without the first metal layer. The stripping device can be a dissolution stripping device, a thermal decomposition stripping device or a mechanical stripping device. These devices are all known devices.

[0029] Further, the preparation system of the composite conductive film further comprises a second film plating device for depositing a second metal layer on the exposed first surface; the second film plating device can be an evaporation device and a magnetron sputtering device, which are also existing.

[0030] Further, the preparation system of the composite conductive film further comprises a transmission mechanism for sequentially transferring the substrate to each device; wherein the composite device is located downstream of the punching device, and the peeling device is located between the first film plating device and the second film plating device.

[0031] In summary, the preparation method of the composite conductive film comprises the following steps: (S1) providing a porous substrate film with a plurality of through holes; (S2) compounding a non-porous sacrificial layer on a first surface of the porous substrate film, so that the non-porous sacrificial layer covers the first surface and seals the first end opening of the through hole; (S3) depositing a first metal layer on the exposed second surface of the porous substrate film, the first metal layer covers the second surface and extends to cover the inner wall of the through hole; (S4) removing the non-porous sacrificial layer to expose the first surface of the porous substrate film and the first end opening of the through hole; (S5) depositing a second metal layer on the exposed first surface, the second metal layer covers the first surface and extends to cover the inner wall of the through hole, and forms a continuous conductive path with the first metal layer in the through hole; wherein the first metal layer and the second metal layer together constitute a double-sided metallized composite conductive film penetrating through the porous substrate film. Through the above preparation method, the winding mass production film plating of the porous substrate film can be realized, and the existence of the non-porous sacrificial layer solves the problem of main drum pollution in the manufacturing process of the porous substrate film. The composite conductive film prepared by the above preparation method has lower internal resistance and higher conductivity, which can reduce the overcurrent heating of the tab in the battery. The composite conductive film can be compatible with ultrasonic spot welding, roll welding, pressure fusion welding and other welding processes.

[0032] It can be understood that, for those skilled in the art, equivalent replacements or changes can be made according to the technical solutions and the inventive concept of the present application, and all these changes or replacements shall belong to the protection scope of the appended claims of the present application.

Claims

1. A method for producing a composite conductive film, characterized by comprising the steps of: The method comprises the following steps: ​ (S1) providing a porous substrate film with a plurality of through-holes; (S2) compounding a non-porous sacrificial layer on a first surface of the porous substrate film, so that the non-porous sacrificial layer covers the first surface and seals first end openings of the through-holes; (S3) depositing a first metal layer on an exposed second surface of the porous substrate film, the first metal layer covering the second surface and extending to cover inner walls of the through-holes; (S4) removing the non-porous sacrificial layer to expose the first surface of the porous substrate film and the first end openings of the through-holes; (S5) depositing a second metal layer on the exposed first surface, the second metal layer covering the first surface and extending to cover the inner walls of the through-holes, and forming a continuous conductive path with the first metal layer in the through-holes.

2. The method of claim 1, wherein the conductive film is a composite conductive film. The porous substrate film with a plurality of through-holes in step (S1) can be a finished substrate film with holes or a porous substrate film with a plurality of through-holes formed on a non-porous substrate film by laser drilling, mechanical punching or chemical etching.

3. The method for preparing the composite conductive film according to claim 1, characterized in that, The compounding in step (S2) is achieved by hot-press compounding, adhesive compounding or melt lamination.

4. The method of claim 1, wherein the composite conductive film is prepared by a method comprising: The removal in step (S4) is achieved by dissolution peeling, thermal decomposition peeling or mechanical peeling. ​ 5. The method for preparing the composite conductive film according to claim 1, characterized in that, The porous substrate film is a polyimide film, a polyester film, a polyolefin microporous film or an aramid fiber film.

6. A composite conductive film prepared according to the method of any one of claims 1 to 5, characterized in that, The method comprises: a porous substrate film with a plurality of through-holes; a first metal layer covering a second surface of the porous substrate film; a second metal layer covering a first surface of the porous substrate film; wherein the first metal layer and the second metal layer form a three-dimensional interconnection conductive network through a metal conductive layer covering inner walls of the through-holes.

7. The composite conductive film according to claim 6, wherein The materials of the first metal layer and the second metal layer are independently selected from copper, aluminum, nickel or alloys thereof.

8. A system for preparing the composite conductive film according to claim 7, characterized by, The method comprises: a punching device for forming through-holes on a porous substrate film; a compounding device for compounding a non-porous sacrificial layer on a first surface of the porous substrate film; a first plating device for depositing a first metal layer on a second surface of the porous substrate film; a peeling device for removing the non-porous sacrificial layer; a second plating device for depositing a second metal layer on the exposed first surface; a transmission mechanism for sequentially transferring the substrate to each device; wherein the compounding device is located downstream of the punching device, and the peeling device is located between the first plating device and the second plating device.

9. The system of composite conductive films of claim 1, wherein, The first plating device and the second plating device are independently a vacuum evaporation cabin, a magnetron sputtering cabin or a chemical plating tank.

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