Multi-metal protection composite copper foil for solid-state lithium battery and preparation method of multi-metal protection composite copper foil

Abstract

The invention discloses a multi-metal protection composite copper foil for a solid-state lithium battery and a preparation method of the multi-metal protection composite copper foil. The multi-metal protection composite copper foil for the solid-state lithium battery comprises a base film layer, a first conductive structure arranged on the front surface of the base film layer and a second conductive structure arranged on the back surface of the base film layer, the base membrane layer is a porous membrane layer or a fiber membrane layer; the first conductive structure comprises a first isolation layer, a first bonding layer, a first conductive copper layer and a first protection layer; the second conductive structure comprises a second isolation layer, a second combination layer, a second conductive copper layer and a second protection layer. The weight of the solid-state lithium battery can be reduced, the manufacturing cost of the solid-state lithium battery can be reduced, the service life of the solid-state lithium battery can be prolonged, and the charging and discharging speed of the solid-state lithium battery can be increased.

Description

Technical Field

[0001] The present invention relates to the technical field of battery production, and in particular to a multi-metal protective composite copper foil for solid-state lithium batteries and a preparation method thereof. Background Art

[0002] Existing solid-state lithium batteries generally use copper foil as the negative electrode current collector. Since copper foil is generally solid copper, it is heavy, and the amount of copper material used is large and the cost is high, which leads to the heavy weight of the solid-state lithium battery and increases the manufacturing cost of the solid-state lithium battery. At the same time, the copper foil is easily corroded by the electrolyte in the solid-state lithium battery, and the service life is short, thereby reducing the service life of the solid-state lithium battery. In addition, during the charge and discharge process of the solid-state lithium battery, since there are no holes on the copper foil for the lithium ions in the electrolyte to pass through, the speed at which the lithium ions in the electrolyte move from one side of the copper foil to the other side of the copper foil will be relatively slow, reducing the charge and discharge speed of the solid-state lithium battery. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the present invention provides a multi-metal protective composite copper foil for a solid-state lithium battery and a preparation method thereof, which can reduce the weight of the solid-state lithium battery and reduce the manufacturing cost of the solid-state lithium battery, while extending the service life of the solid-state lithium battery and increasing the charging and discharging speed of the solid-state lithium battery.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A first aspect of the present invention provides a multi-metal protective composite copper foil for a solid-state lithium battery, comprising a base film layer, a first conductive structure arranged on the front side of the base film layer, and a second conductive structure arranged on the back side of the base film layer; the base film layer is a porous film layer or a fiber film layer; the first conductive structure comprises a first isolation layer, a first bonding layer, a first conductive copper layer and a first protective layer, the first isolation layer is arranged on the front side of the base film layer, the first bonding layer is arranged on the side of the first isolation layer away from the base film layer, the first conductive copper layer is arranged on the side of the first bonding layer away from the first isolation layer, and the first protective layer is arranged on the side of the first conductive copper layer away from the first bonding layer; the second conductive structure comprises a second isolation layer, a second bonding layer, a second conductive copper layer and a second protective layer, the second isolation layer is arranged on the back side of the base film layer, the second bonding layer is arranged on the side of the second isolation layer away from the base film layer, the second conductive copper layer is arranged on the side of the second bonding layer away from the second isolation layer, and the second protective layer is arranged on the side of the second conductive copper layer away from the second bonding layer.

[0006] As a preferred technical solution, the porous membrane layer is a PET porous membrane layer, a PP porous membrane layer, a PI porous membrane layer or a PE porous membrane layer.

[0007] As a preferred technical solution, the fiber membrane layer is a PET fiber membrane layer, a PP fiber membrane layer, a PI fiber membrane layer or a PE fiber membrane layer.

[0008] As a preferred technical solution, the pores of the porous membrane layer or fiber membrane layer have a pore size of 0.05-500 μm and a porosity of 0.1%-80%.

[0009] As a preferred technical solution, the materials of the first isolation layer, the second isolation layer, the first protective layer and the second protective layer are all one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese.

[0010] As a preferred technical solution, the first bonding layer and the second bonding layer are both made of copper or copper alloy.

[0011] As a preferred technical solution, the thickness of the base film layer is 1-30 μm.

[0012] As a preferred technical solution, the thickness of the first isolation layer and the second isolation layer are both 5-100 nm, the thickness of the first bonding layer and the second bonding layer are both 10-200 nm, and the thickness of the first protective layer and the second protective layer are both 5-2000 nm.

[0013] As a preferred technical solution, the thickness of the first conductive copper layer and the second conductive copper layer are both 500-2000 nm.

[0014] A second aspect of the present invention provides a method for preparing a multi-metal protective composite copper foil for a solid-state lithium battery, comprising the following steps:

[0015] S1. Providing a base membrane layer, wherein the base membrane layer is a porous membrane layer or a fiber membrane layer;

[0016] S2, setting a first conductive structure on the front side of the base film layer;

[0017] S3, setting a second conductive structure on the back side of the base film layer;

[0018] Step S2 includes the following steps:

[0019] S21, providing a first isolation layer on the front side of the base film layer by magnetron sputtering, evaporation or chemical plating;

[0020] S22, disposing a first bonding layer on a side of the first isolation layer away from the base film layer by magnetron sputtering, evaporation or chemical plating;

[0021] S23, disposing a first conductive copper layer on a side of the first bonding layer away from the first isolation layer by electroplating or evaporation;

[0022] S24, providing a first protective layer on a side of the first conductive copper layer away from the first bonding layer by magnetron sputtering or evaporation;

[0023] Step S3 includes the following steps:

[0024] S31, providing a second isolation layer on the back side of the base film layer by magnetron sputtering, evaporation or chemical plating;

[0025] S32, disposing a second bonding layer on a side of the second isolation layer away from the base film layer by magnetron sputtering, evaporation or chemical plating;

[0026] S33, disposing a second conductive copper layer on a side of the second bonding layer away from the second isolation layer by electroplating or evaporation;

[0027] S34, disposing a second protective layer on a side of the second conductive copper layer away from the second bonding layer by magnetron sputtering or evaporation.

[0028] The beneficial effects of the present invention are as follows: the present invention can reduce the weight of the composite copper foil and the amount of copper material by setting the base film layer, thereby reducing the weight of the solid-state lithium battery and the manufacturing cost of the solid-state lithium battery. The first conductive copper layer and the second conductive copper layer can meet the current carrying performance requirements and tensile strength requirements of the composite copper foil, thereby meeting the performance requirements of the solid-state lithium battery. The first protective layer and the second protective layer can protect the first conductive copper layer and the second conductive copper layer respectively, thereby preventing the electrolyte in the solid-state lithium battery from corroding the first conductive copper layer and the second conductive copper layer, prolonging the service life of the composite copper foil, thereby prolonging the service life of the solid-state lithium battery. The base film layer is a porous film layer or a fiber film layer. During the charging and discharging process of the solid-state lithium battery, the holes on the porous film layer or the holes on the fiber film layer can serve as channels for the movement of lithium ions in the electrolyte, so that the lithium ions in the electrolyte of the solid-state lithium battery can quickly move from one side of the composite copper foil to the other side of the composite copper foil, thereby improving the charging and discharging speed of the solid-state lithium battery. In addition, by setting the first isolation layer and the second isolation layer, the first conductive copper layer and the base film layer can be isolated, and the second conductive copper layer and the base film layer can be isolated, thereby protecting the base film layer. During the high and low temperature cycle test of the solid-state lithium battery, the base film layer can be prevented from being burned through, thereby improving the stability of the composite copper foil during the high and low temperature cycle test of the solid-state lithium battery. By setting the first bonding layer and the second bonding layer, the adhesion between the first isolation layer and the first conductive copper layer, and the adhesion between the second isolation layer and the second conductive copper layer can be improved, and the first conductive copper layer and the second conductive copper layer can be prevented from falling off. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Figure 1 This is a schematic structural diagram of a multi-metal protective composite copper foil for a solid-state lithium battery provided by one embodiment of the present invention;

[0031] Figure 2 is based on Figure 1 The multi-metal protective composite copper foil for solid-state lithium batteries shown is a flowchart schematic diagram of a method for preparing a multi-metal protective composite copper foil for solid-state lithium batteries;

[0032] Figure 3 yes Figure 2 A schematic flow chart diagram of step S2 of a method for preparing a multi-metal protective composite copper foil for a solid-state lithium battery is shown;

[0033] Figure 4 yes Figure 2 The flowchart schematic diagram of step S3 of the method for preparing multi-metal protective composite copper foil for solid-state lithium batteries is shown. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by technicians in this field without creative work are all within the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the formation of a better connection structure by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the invention can be combined interchangeably without conflicting with each other.

[0035] Please refer to Figure 1 An embodiment of the present invention provides a multi-metal protective composite copper foil for a solid-state lithium battery, comprising a base film layer 10, a first conductive structure 20 arranged on the front side of the base film layer 10, and a second conductive structure 30 arranged on the back side of the base film layer 10.

[0036] The base membrane layer 10 is a porous membrane layer or a fiber membrane layer.

[0037] The first conductive structure 20 includes a first isolation layer 21, a first bonding layer 22, a first conductive copper layer 23 and a first protective layer 24. The first isolation layer 21 is arranged on the front side of the base film layer 10. The first bonding layer 22 is arranged on a side of the first isolation layer 21 away from the base film layer 10. The first conductive copper layer 23 is arranged on a side of the first bonding layer 22 away from the first isolation layer 21. The first protective layer 24 is arranged on a side of the first conductive copper layer 23 away from the first bonding layer 22.

[0038] The second conductive structure 30 includes a second isolation layer 31, a second bonding layer 32, a second conductive copper layer 33, and a second protective layer 34. The second isolation layer 31 is disposed on the back side of the base film layer 10. The second bonding layer 32 is disposed on a side of the second isolation layer 31 away from the base film layer 10. The second conductive copper layer 33 is disposed on a side of the second bonding layer 32 away from the second isolation layer 31. The second protective layer 34 is disposed on a side of the second conductive copper layer 33 away from the second bonding layer 32.

[0039] Through the above structure, the composite copper foil of the present invention, the base film layer 10 serves as the supporting layer of the entire composite copper foil, has the characteristics of light weight, low cost and good ductility, can reduce the weight of the composite copper foil and can reduce the amount of copper material, thereby reducing the weight of the solid-state lithium battery and the manufacturing cost of the solid-state lithium battery, and at the same time can improve the ductility of the composite copper foil, the first conductive copper layer 23 and the second conductive copper layer 33 are set, and have good conductivity, which can meet the current-carrying performance requirements and tensile strength requirements of the composite copper foil, thereby meeting the performance requirements of the solid-state lithium battery, the first isolation layer 21 and the second isolation layer 31 are set, and the first conductive copper layer 23 and the base film layer 10 can be isolated, and the second conductive copper layer 33 and the base film layer 10 can be isolated, thereby protecting the base film layer 10, and during the high and low temperature cycle test of the solid-state lithium battery, the base film can be avoided. The layer 10 is burned through, thereby improving the stability of the composite copper foil during the high and low temperature cycle test of the solid-state lithium battery. The first bonding layer 22 is set to improve the adhesion between the first isolation layer 21 and the first conductive copper layer 23, and prevent the first conductive copper layer 23 from falling off. The second bonding layer 32 is set to improve the adhesion between the second isolation layer 31 and the second conductive copper layer 33, and prevent the second conductive copper layer 33 from falling off. The first protective layer 24 is set to protect the first conductive copper layer 23, thereby preventing the solid electrolyte in the solid-state lithium battery from corroding the first conductive copper layer 23. The second protective layer 34 is set to protect the second conductive copper layer 33, thereby preventing the solid electrolyte in the solid-state lithium battery from corroding the second conductive copper layer 33, extending the service life of the composite copper foil, thereby extending the service life of the solid-state lithium battery. In addition, the base membrane layer 10 is a porous membrane layer or a fiber membrane layer. During the charge and discharge process of the solid-state lithium battery, the holes on the porous membrane layer or the holes on the fiber membrane layer can serve as channels for the movement of lithium ions in the electrolyte, so that the lithium ions in the electrolyte of the solid-state lithium battery can quickly move from one side of the composite copper foil to the other side of the composite copper foil, thereby improving the charge and discharge speed of the solid-state lithium battery.

[0040] In this embodiment, the front and back sides of the base film layer 10 are respectively provided with a first isolation layer 21 and a second isolation layer 31 by magnetron sputtering, evaporation or chemical plating methods, the first bonding layer 22 is provided on the side of the first isolation layer 21 away from the base film layer 10 by magnetron sputtering, evaporation or chemical plating methods, the second bonding layer 32 is provided on the side of the second isolation layer 31 away from the base film layer 10 by magnetron sputtering, evaporation or chemical plating methods, the first conductive copper layer 23 is provided on the side of the first bonding layer 22 away from the first isolation layer 21 by electroplating or evaporation methods, the second conductive copper layer 33 is provided on the side of the second bonding layer 32 away from the second isolation layer 31 by electroplating or evaporation methods, the first conductive copper layer 23 is provided on the side of the first bonding layer 22 away from the first bonding layer 22 by magnetron sputtering or evaporation methods, and the second protective layer 34 is provided on the side of the second conductive copper layer 33 away from the second bonding layer 32 by magnetron sputtering or evaporation methods.

[0041] The porous membrane layer is a PET (Polyethylene terephthalate, polyethylene terephthalate plastic) porous membrane layer, a PP (Polypropylene, polypropylene) porous membrane layer, a PI (Polyimide, polyimide) porous membrane layer or a PE (Polyethylene, polyethylene) porous membrane layer. The density of the PET porous membrane layer, the PP porous membrane layer, the PI porous membrane layer, and the PE porous membrane layer is low, which can further reduce the weight of the composite copper foil, thereby further reducing the weight of the solid-state lithium battery, and is easy to manufacture.

[0042] The fiber membrane layer is a PET fiber membrane layer, a PP fiber membrane layer, a PI fiber membrane layer or a PE fiber membrane layer. The density of the PET fiber membrane layer, the PP fiber membrane layer, the PI fiber membrane layer and the PE fiber membrane layer is low, which can further reduce the weight of the composite copper foil, thereby further reducing the weight of the solid-state lithium battery and facilitating manufacturing.

[0043] The pores of the porous membrane layer or the fiber membrane layer have a pore size of 0.05-500μm and a porosity of 0.1%-80%, which can ensure that lithium ions can pass through the pores. When the first isolation layer 21 and the second isolation layer 31 are respectively arranged on the front and back sides of the base membrane layer 10 by magnetron sputtering, evaporation or chemical plating, metal filling in the pores can be avoided.

[0044] The materials of the first isolation layer 21, the second isolation layer 31, the first protective layer 24 and the second protective layer 34 are all one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese. A dense isolation layer can be formed by using a variety of combinations of metals. When the material of the first protective layer 24 and the second protective layer 34 is lithium, the first protective layer 24 and the second protective layer 34 can also play a role in replenishing the number of lithium ions in the electrolyte of the solid-state lithium battery, thereby improving the capacity and service life of the solid-state lithium battery.

[0045] The first bonding layer 22 and the second bonding layer 32 are both made of copper or copper alloy, and the first conductive copper layer 23 and the second conductive copper layer 33 are both made of copper. The first bonding layer 22 and the second bonding layer 32 use copper or copper alloy. When the first conductive copper layer 23 is provided on a side of the first bonding layer 22 away from the first isolation layer 21 by electroplating or evaporation, and when the second conductive copper layer 33 is provided on a side of the second bonding layer 32 away from the second isolation layer 31 by electroplating or evaporation, the speed of generating the first conductive copper layer 23 and the second conductive copper layer 33 can be increased.

[0046] The thickness of the base film layer 10 is 1-30μm (micrometer), preferably 10μm, the thickness of the first isolation layer 21 and the second isolation layer 31 are both 5-100nm (nanometer), preferably 50nm, the thickness of the first bonding layer 22 and the second bonding layer 32 are both 10-200nm, preferably 100nm, the thickness of the first conductive copper layer 23 and the second conductive copper layer 33 are both 500-2000nm, preferably 1000nm, the thickness of the first protective layer 24 and the second protective layer 34 are both 5-2000nm, preferably 1000nm. With this thickness, the total thickness of the composite copper foil of the present invention is between 2.04-38.6μm. The small thickness can further reduce the weight of the composite copper foil, thereby further reducing the weight of the solid-state lithium battery.

[0047] Please refer to Figure 2 Based on the above-mentioned solid-state lithium battery composite copper foil, the present invention also provides a method for preparing a solid-state lithium battery composite copper foil, comprising the following steps:

[0048] S1. Provide a base film layer 10. The width and length of the base film layer 10 can be set according to actual conditions. The thickness of the base film layer 10 is 1-30 μm. The base film layer 10 is a porous film layer or a fiber film layer. The porous film layer is a PET porous film layer, a PP porous film layer, a PI porous film layer or a PE porous film layer. The fiber film layer is a PET fiber film layer, a PP fiber film layer, a PI fiber film layer or a PE fiber film layer. The pores of the porous film layer or the fiber film layer have a pore size of 0.05-500 μm and a porosity of 0.1%-80%.

[0049] S2. Dispose a first conductive structure 20 on the front surface of the base film layer 10.

[0050] like Figure 3 As shown, step S2 includes the following steps:

[0051] S21, a first isolation layer 21 is provided on the front surface of the base film layer 10 by magnetron sputtering, evaporation or chemical plating. The material of the first isolation layer 21 is one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese. The thickness of the first isolation layer 21 is 5-100 nm.

[0052] S22, a first bonding layer 22 is provided on a side of the first isolation layer 21 away from the base film layer 10 by magnetron sputtering, evaporation or chemical plating. The first bonding layer 22 is made of copper or copper alloy. The thickness of the first bonding layer 22 is 10-200 nm.

[0053] S23, a first conductive copper layer 23 is provided on a side of the first bonding layer 22 away from the first isolation layer 21 by electroplating or evaporation. The first conductive copper layer 23 is made of copper, and has a thickness of 500-2000 nm.

[0054] S24, a first protective layer 24 is provided on a side of the first conductive copper layer 23 away from the first bonding layer 22 by magnetron sputtering or evaporation. The material of the first protective layer 24 is one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese. The thickness of the first protective layer 24 is 5-2000 nm.

[0055] S3. Dispose a second conductive structure 30 on the back side of the base film layer 10.

[0056] like Figure 4 As shown, step S3 includes the following steps:

[0057] S31, a second isolation layer 31 is provided on the back of the base film layer 10 by magnetron sputtering, evaporation or chemical plating. The material of the second isolation layer 31 is one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese. The thickness of the second isolation layer 31 is 5-100 nm.

[0058] S32, a second bonding layer 32 is provided on a side of the second isolation layer 31 away from the base film layer 10 by magnetron sputtering, evaporation or chemical plating. The second bonding layer 32 is made of copper or copper alloy. The thickness of the second bonding layer 32 is 10-200 nm.

[0059] S33, a second conductive copper layer 33 is provided on a side of the second bonding layer 32 away from the second isolation layer 31 by electroplating or evaporation. The second conductive copper layer 33 is made of copper, and has a thickness of 500-2000 nm.

[0060] S34, a second protective layer 34 is provided on a side of the second conductive copper layer 33 away from the second bonding layer 32 by magnetron sputtering or evaporation. The material of the second protective layer 34 is one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese. The thickness of the second protective layer 34 is 5-2000 nm.

[0061] The preparation method of the present invention has a simple process and is easy to manufacture. The prepared composite copper foil is light in weight and low in cost, thereby reducing the weight of the solid-state lithium battery and reducing the manufacturing cost of the solid-state lithium battery. At the same time, it can extend the service life of the solid-state lithium battery and improve the charge and discharge speed of the solid-state lithium battery, thereby greatly meeting the use requirements.

[0062] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A multi-metal protective composite copper foil for solid-state lithium batteries, characterized in that: It includes a base film layer, a first conductive structure arranged on the front side of the base film layer, and a second conductive structure arranged on the back side of the base film layer; The base membrane layer is a porous membrane layer or a fiber membrane layer; The first conductive structure comprises a first isolation layer, a first bonding layer, a first conductive copper layer and a first protective layer, wherein the first isolation layer is arranged on the front side of the base film layer, the first bonding layer is arranged on a side of the first isolation layer away from the base film layer, the first conductive copper layer is arranged on a side of the first bonding layer away from the first isolation layer, and the first protective layer is arranged on a side of the first conductive copper layer away from the first bonding layer; The second conductive structure includes a second isolation layer, a second bonding layer, a second conductive copper layer and a second protective layer. The second isolation layer is arranged on the back side of the base film layer, the second bonding layer is arranged on the side of the second isolation layer away from the base film layer, the second conductive copper layer is arranged on the side of the second bonding layer away from the second isolation layer, and the second protective layer is arranged on the side of the second conductive copper layer away from the second bonding layer.

2. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The porous membrane layer is a PET porous membrane layer, a PP porous membrane layer, a PI porous membrane layer or a PE porous membrane layer.

3. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The fiber membrane layer is a PET fiber membrane layer, a PP fiber membrane layer, a PI fiber membrane layer or a PE fiber membrane layer.

4. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The pores of the porous membrane layer or the fiber membrane layer have a pore size of 0.05-500 μm and a porosity of 0.1%-80%.

5. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The materials of the first isolation layer, the second isolation layer, the first protective layer and the second protective layer are all one or more combinations of cobalt, aluminum, nickel, cadmium, magnesium, lithium and manganese.

6. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The first bonding layer and the second bonding layer are both made of copper or copper alloy.

7. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The thickness of the base film layer is 1-30 μm.

8. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The thickness of the first isolation layer and the second isolation layer are both 5-100 nm, the thickness of the first bonding layer and the second bonding layer are both 10-200 nm, and the thickness of the first protection layer and the second protection layer are both 5-2000 nm.

9. The multi-metal protective composite copper foil for solid-state lithium batteries according to claim 1, characterized in that: The thickness of the first conductive copper layer and the second conductive copper layer are both 500-2000 nm.

10. A method for preparing a multi-metal protective composite copper foil for solid-state lithium batteries, characterized in that: The following steps are involved: S1. Providing a base membrane layer, wherein the base membrane layer is a porous membrane layer or a fiber membrane layer; S2, setting a first conductive structure on the front side of the base film layer; S3, setting a second conductive structure on the back side of the base film layer; Step S2 includes the following steps: S21, providing a first isolation layer on the front side of the base film layer by magnetron sputtering, evaporation or chemical plating; S22, disposing a first bonding layer on a side of the first isolation layer away from the base film layer by magnetron sputtering, evaporation or chemical plating; S23, disposing a first conductive copper layer on a side of the first bonding layer away from the first isolation layer by electroplating or evaporation; S24, providing a first protective layer on a side of the first conductive copper layer away from the first bonding layer by magnetron sputtering or evaporation; Step S3 includes the following steps: S31, providing a second isolation layer on the back side of the base film layer by magnetron sputtering, evaporation or chemical plating; S32, disposing a second bonding layer on a side of the second isolation layer away from the base film layer by magnetron sputtering, evaporation or chemical plating; S33, disposing a second conductive copper layer on a side of the second bonding layer away from the second isolation layer by electroplating or evaporation; S34, disposing a second protective layer on a side of the second conductive copper layer away from the second bonding layer by magnetron sputtering or evaporation.

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