Composite copper foil, manufacturing method, and lithium ion battery

Abstract

The present disclosure relates to the technical field of lithium ion batteries, in particular to a composite copper foil, a manufacturing method and a lithium ion battery. The manufacturing method of the composite copper foil comprises: taking a composite copper foil with partial copper film peeling as a quasi-base film, and attaching a polymer material to the surface of the quasi-base film to obtain a base film; and depositing a copper metal layer on the two side surfaces of the base film. The above technical solution improves the defective product into a base film by attaching a polymer material to the surface of the composite copper foil with partial copper film peeling, and further deposits a copper metal layer on the two side surfaces of the base film to obtain a composite copper foil meeting the requirements, thereby realizing the reuse of defective products and reducing the cost.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of lithium ion batteries, in particular to a composite copper foil, a manufacturing method and a lithium ion battery. BACKGROUND

[0002] The composite copper foil is a sandwich structure of "copper-polymer-copper" formed by depositing a copper layer on the upper and lower surfaces of a polymer material as a base film. The composite copper foil has the characteristics of small density, thin thickness and good electrical conductivity, and thus has the potential to replace traditional lithium electrolytic copper foil. The production yield of the composite copper foil is about 85% at present, and the defective products often have the problem of copper foil falling off. Therefore, how to process and reuse the defective products is a technical problem to be solved. SUMMARY

[0003] In order to solve the problems in the related art, the embodiments of the present disclosure provide a composite copper foil, a manufacturing method and a lithium ion battery.

[0004] In a first aspect, the embodiments of the present disclosure provide a manufacturing method of a composite copper foil, comprising:

[0005] The composite copper foil with the copper film partially falling off is used as a quasi-base film, and a polymer material is attached to the surface of the quasi-base film to obtain a base film;

[0006] A copper metal layer is deposited on the two side surfaces of the base film.

[0007] According to the embodiments of the present disclosure, a nano-injection molding process is used to attach a polymer material to the surface of the quasi-base film to obtain a base film.

[0008] According to the embodiments of the present disclosure, the deposition of the copper metal layer on the two side surfaces of the base film comprises:

[0009] A magnetron sputtering process combined with an electroless plating process is used to deposit a copper metal layer on the two side surfaces of the base film;

[0010] The magnetron sputtering process includes a pre-stage and a subsequent stage. In the pre-stage, a 10-15nm thin film is formed on the two side surfaces of the base film. After adjusting the parameters of the magnetron sputtering, the process enters the subsequent stage. Copper is continued to be plated on the 10-15nm thin film, and finally a 25-40nm thin film is formed.

[0011] According to the embodiments of the present disclosure, the adjustment of the parameters of the magnetron sputtering comprises the following steps:

[0012] The surface image of the base film and the image in the thickness direction of the base film are obtained;

[0013] The flatness of the surface of the thin film obtained in the pre-stage is determined according to the surface image of the base film and the image in the thickness direction of the base film;

[0014] The parameters of the magnetron sputtering are adjusted according to the flatness of the film surface.

[0015] In a second aspect, the embodiments of the present disclosure provide a composite copper foil obtained by the method for manufacturing the composite copper foil according to any one of the first aspect.

[0016] According to embodiments of the present disclosure, the composite copper foil comprises:

[0017] The first film layer is a polymer material;

[0018] The first copper film is located above the first film layer;

[0019] The second film layer is a polymer material and is located above the first copper film;

[0020] The second copper film is located above the second film layer;

[0021] The third copper film is located below the first film layer;

[0022] The first film layer and the first copper film constitute the composite copper foil with partial copper film peeling; and the first film layer, the first copper film, and the second film layer constitute the base film.

[0023] According to embodiments of the present disclosure, the composite copper foil comprises:

[0024] The first film layer is a polymer material;

[0025] The first copper film is located above the first film layer;

[0026] The second copper film is located below the first film layer;

[0027] The second film layer is a polymer material and is located above the first copper film and the second copper film respectively;

[0028] The third copper film is located above the second film layer respectively;

[0029] The first film layer, the first copper film, and the second copper film constitute the composite copper foil with partial copper film peeling; and the first film layer, the first copper film, the second copper film, and the second film layer constitute the base film.

[0030] According to embodiments of the present disclosure, the first copper film is a continuous copper film or a discontinuous copper film.

[0031] According to embodiments of the present disclosure, the first copper film is a continuous copper film or a discontinuous copper film; and / or, the second copper film is a continuous copper film or a discontinuous copper film.

[0032] In a third aspect, the embodiments of the present disclosure provide a lithium ion battery comprising the composite copper foil according to any one of the second aspect.

[0033] The manufacturing method of the composite copper foil according to the embodiment of the present disclosure comprises: taking the composite copper foil with partial copper film falling off as a quasi-base film, and attaching a polymer material to the surface of the quasi-base film to obtain a base film; and depositing a copper metal layer on both sides of the base film. The above technical solution improves the defective product into a base film by attaching a polymer material to the surface of the composite copper foil with partial copper film falling off, and further deposits a copper metal layer on both sides of the base film to obtain a required composite copper foil, thereby realizing the reuse of defective products and reducing the cost.

[0034] It should be understood that the general description above and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0035] Other features, objects, and advantages of the present disclosure will become more apparent from the following detailed description of the non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0036] Figure 1 A structure schematic diagram of a composite copper foil according to an embodiment of the present disclosure is shown.

[0037] Figure 2 A structure schematic diagram of a composite copper foil according to another embodiment of the present disclosure is shown.

[0038] Figure 3 A flowchart of a manufacturing method of a composite copper foil according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0039] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily implement them. In addition, parts irrelevant to the description of the exemplary embodiments are omitted in the drawings for the sake of clarity.

[0040] In the present disclosure, it should be understood that terms such as "include" or "have" are intended to indicate the presence of features, numbers, steps, actions, components, parts or combinations thereof disclosed in the specification, and do not exclude the presence or addition of one or more other features, numbers, steps, actions, components, parts or combinations thereof.

[0041] In addition, it should be further noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0042] The composite copper foil is a sandwich structure of "copper-polymer-copper" formed by depositing copper layers on the upper and lower surfaces of a polymer film as a base film. The composite copper foil has the advantages of small density, thin thickness, good conductivity, etc., and thus has the potential to replace traditional lithium electrolytic copper foil. The production yield of the composite copper foil is about 85% at present, and the defective products often have copper foil peeling. Therefore, how to process and reuse the defective products is a technical problem to be solved.

[0043] Figure 1 A structure diagram of a composite copper foil according to an embodiment of the present disclosure is shown.

[0044] As shown in Figure 1 The composite copper foil includes a first film layer 111, a first copper film 112, a second film layer 12, a second copper film 13, and a third copper film 14. The first film layer 111, the first copper film 112, and the second film layer 12 constitute a base film. The second copper film 13 and the third copper film 14 are copper metal layers deposited on the two surfaces of the base film. The second copper film 13 is located above the second film layer 12, and the third copper film 14 is located below the first film layer 111. The second copper film 13 includes a sputtering layer 131 and an electroplating layer 132. The sputtering layer 131 is located on the surface of the base film, and the electroplating layer 132 is located above the sputtering layer 131. The third copper film 14 includes a sputtering layer 141 and an electroplating layer 142. The sputtering layer 141 is located on the surface of the base film, and the electroplating layer 142 is located above the sputtering layer 141.

[0045] The composite copper foil is usually a sandwich structure of "copper-polymer-copper". In the present disclosure, the first film layer 111 and the first copper film 112 constitute a composite copper foil 11 with partial copper film peeling, i.e., the upper or lower copper foil in the sandwich structure is peeled off. Such a composite copper foil with partial copper film peeling is usually a defective product. Based on the defective product, the present disclosure forms a second film layer to improve the defective product into a base film, and further deposits copper metal layers on the two surfaces of the base film to obtain a composite copper foil meeting the requirements, thereby realizing the reuse of the defective product and reducing the cost.

[0046] Figure 1 In the shown composite copper foil 11, the first copper film 112 is a continuous copper film, i.e., there is no area of copper film peeling on the surface of the first film layer 111. It can be understood that the first copper film 112 can also be a discontinuous copper film, i.e., there is an area of copper film peeling on the surface of the first film layer 111. Such a defective product can also be improved into a base film by forming a second film layer, which will not be described here.

[0047] According to an embodiment of the present disclosure, the first film layer 111 and the second film layer 12 are both high polymer materials, for example, polyethylene terephthalate (PET) material, polypropylene (PP) material, or polyimide (PI) material, etc. The materials of the first film layer 111 and the second film layer 12 can be the same or different, which is not limited in the present disclosure.

[0048] According to an embodiment of the present disclosure, the second film layer 12 can be attached to the first copper film 112 by nano-injection molding process.

[0049] Nano-injection molding refers to nano molding technology (NMT), that is, the surface of the metal is first nano-treated, and then the plastic is directly injection molded on the metal surface, so that the metal and the plastic can be integrally formed. The "nano" refers to a microporous process, that is, the surface of the metal is treated by a specific solution to form micropores at the nano level, and the main purpose is to better combine the metal surface with the plastic and improve the connection strength.

[0050] According to an embodiment of the present disclosure, the sputtering layer 131 and the sputtering layer 141 are nickel-chromium alloy layers or copper layers. The sputtering layer is prepared by a magnetron sputtering process. The sputtering layer is preferably a nickel-chromium alloy layer. Compared with a copper layer, the nickel-chromium alloy layer usually has a certain degree of porosity, thereby providing a certain roughness for the upper electroplated layer and improving the adhesion performance of the electroplated layer. Of course, the sputtering layer can also be a copper layer, which is not limited in the present disclosure. The electroplated layer 132 and the electroplated layer 142 are copper layers, which are prepared by a water electroplating process or a vacuum evaporation process combined with a water electroplating process. The thickness of the sputtering layer is increased to 1 μm to meet the use requirements of the composite copper foil.

[0051] Figure 2 A structure schematic diagram of a composite copper foil according to another embodiment of the present disclosure is shown.

[0052] As shown in Figure 2 The composite copper foil includes a first film layer 211, a first copper film 212, a second copper film 213, a second film layer 22, and a third copper film 23. The first film layer 211, the first copper film 212, the second copper film 213, and the second film layer 22 constitute a base film. The third copper film 23 is a copper metal layer deposited on both surfaces of the base film. The third copper film 23 is located above the second film layer 22. The third copper film 23 includes a sputtering layer 231 and an electroplated layer 232. The sputtering layer 231 is located on the surface of the base film, and the electroplated layer 232 is located above the sputtering layer 231.

[0053] The composite copper foil is usually a "copper-polymer-copper" composite sandwich structure. In the present disclosure, the first film layer 211, the first copper film 212, and the second copper film 213 constitute a composite copper foil 21 with the copper film partially falling off, and the second film layer 22 and the third copper film 23 constitute a composite copper foil 22 with the copper film completely falling off. Figure 1Different from this, the second copper film 213 does not fall off as a whole, but is partially peeled off from the first film layer 211, and local thinning and other defects can also occur. On the basis of the defective product, the second film layer is formed to improve the defective product into a base film, and further, a copper metal layer is deposited on the two side surfaces of the base film to obtain a required composite copper foil, so that the defective product is reused, and the cost is reduced.

[0054] Figure 2 The first copper film 212 in the illustrated composite copper foil 21 is a continuous copper film, that is, the surface of the first film layer 211 does not have a region where the copper film falls off. It can be understood that the first copper film 212 can also be a discontinuous copper film, that is, the surface of the first film layer 211 has a region where the copper film falls off. Such a defect can also be improved by forming a second film layer to improve the defective product into a base film, which will not be described here.

[0055] Figure 3 A flowchart of a manufacturing method of a composite copper foil according to an embodiment of the present disclosure is shown.

[0056] As shown in Figure 3 , the manufacturing method of the composite copper foil includes the following steps:

[0057] Step one: taking the composite copper foil with partial copper film falling off as a quasi-base film, and attaching a polymer material on the surface of the quasi-base film to obtain a base film;

[0058] Step two: depositing a copper metal layer on the two side surfaces of the base film.

[0059] According to the embodiment of the present disclosure, the composite copper foil with partial copper film falling off can be taken as a quasi-base film in step one. For example, the composite copper foil is a sandwich structure of "copper-polymer-copper", and the double-layer structure after the copper film on the upper layer or the lower layer of the polymer falls off is taken as a quasi-base film, and the first film layer 111 and the first copper film 112 constitute a quasi-base film as shown in Figure 1 , for example, Figure 1 , or the three-layer structure after the copper film on the upper layer or the lower layer of the polymer falls off is taken as a quasi-base film, and the first film layer 211, the first copper film 212 and the second copper film 213 constitute a quasi-base film as shown in Figure 2 , for example, Figure 2 .

[0060] According to the embodiment of the present disclosure, the high polymer material is attached to the surface of the quasi-base film in step one, and the process of nano-injection involved in the present disclosure mainly includes the following steps. First, the copper film is treated by T or E treatment, and nano-sized holes are formed on the surface of the copper film by using T or E treatment agent, so as to ensure that the nano-holes are filled with T or E liquid and the air in the nano-holes is discharged. Then, the surface of the copper film is dried, and finally, the injection is performed in the mold to form a close combination structure of the high polymer material and the copper film. The nano-injection process is a mature technology, and the specific technical details can be referred to the prior art, which will not be described here.

[0061] According to the embodiment of the present disclosure, the copper metal layer is deposited on the two side surfaces of the base film in step two. The commonly used copper plating process includes two-step method and three-step method, and the two-step method or the three-step method can be used to deposit the copper metal layer on the two side surfaces of the base film.

[0062] Specifically, the process flow of the two-step method includes a magnetron sputtering process and an electroplating process. First, a copper metal layer (about 25-40 nm) is plated on the two side surfaces of the base film by the magnetron sputtering process, so that the copper metal layer can be conductive and ensure that the film layer has good density and bonding force. Then, the copper metal layer is thickened to 1 μm by the electroplating process. The three-step method is based on the two-step method, and an evaporation process is added before the electroplating process to accelerate the deposition of the copper metal layer.

[0063] The magnetron sputtering process, i.e. vacuum magnetron sputtering plating, is the first step of the composite copper foil manufacturing process. The vacuum magnetron sputtering plating uses high-energy plasma (mainly argon ions in the composite copper foil manufacturing process) to bombard the target material, so that the target material is sputtered in the form of atomic groups or ions and deposited on the surface of the base film.

[0064] The evaporation process, i.e. vacuum evaporation plating, is the core step of the three-step method. The vacuum evaporation plating is a process of evaporating metal copper in the form of atomic groups or molecular groups under vacuum conditions, and depositing the metal copper on the surface of the base film to form a thin film. The deposition amount of the evaporated metal copper is about three times that of the magnetron sputtering, which can more effectively help the deposition of copper and make the metal layer more uniform, thereby making up for the problem of insufficient thickness of the copper layer in the two-step method.

[0065] The core of the electroplating process is to thicken the metal copper layer to the required thickness. The electroplating is essentially a displacement reaction. The two electrodes for displacement are placed in the solution, and the copper ions in the solution are reduced to copper and deposited on the surface of the base film to form a copper layer with the desired thickness.

[0066] According to the embodiment of the present disclosure, the magnetron sputtering process includes a pre-stage and a subsequent stage, the pre-stage forms a 10-15nm thin film on both sides of the base film, and the subsequent stage continues to deposit copper on the 10-15nm thin film after adjusting the parameters of the magnetron sputtering, and finally forms a 25-40nm thin film.

[0067] Specifically, the adjusting the parameters of the magnetron sputtering includes the following steps:

[0068] obtaining a surface image of the base film and an image in the thickness direction of the base film;

[0069] determining the flatness of the surface of the thin film obtained in the pre-stage according to the surface image of the base film and the image in the thickness direction of the base film;

[0070] adjusting the parameters of the magnetron sputtering according to the flatness of the surface of the thin film.

[0071] In the present disclosure, the thickness of the thin film formed in the pre-stage should not be too large or too small. If it is less than 10nm, it is not conducive to subsequent image acquisition and image analysis. If it is greater than 15nm, it is not convenient to adjust the flatness of the surface of the thin film in the subsequent stage, and it may also be necessary to increase the overall sputtering times, resulting in a decrease in production efficiency.

[0072] In the present disclosure, the surface image of the base film and the image in the thickness direction of the base film can be obtained by using existing image acquisition technology, for example, a high-magnification camera, infrared imaging, etc. The present disclosure does not limit this.

[0073] According to the embodiment of the present disclosure, the adjusted parameters of the magnetron sputtering can include but are not limited to adjusting the sputtering pressure, the sputtering power, the target-substrate distance, the substrate type, the substrate temperature, the background vacuum degree, the linear speed, etc. One or several parameters are adjusted according to the actual situation and experience, and then the magnetron sputtering in the subsequent stage is carried out, so as to improve the flatness of the base film after coating. In the magnetron sputtering, it is difficult to ensure that the argon ions uniformly bombard the target material. Therefore, by adjusting the parameters of the magnetron sputtering and combining multiple magnetron sputtering, the randomness of the bombarded particles is reduced, the flatness of the coating surface after magnetron sputtering is ensured, and the high-temperature cycle test performance of the composite copper foil is improved, so as to meet the use needs.

[0074] Based on the same or similar inventive concept, the present disclosure provides a lithium ion battery including a composite copper foil as a negative electrode end, which is obtained by using the manufacturing method of the composite copper foil described in the above embodiments.

[0075] The above description is merely that of the preferred embodiments of the present disclosure and a description of the technical principles of the present disclosure. It should be understood by those skilled in the art that the inventive scope involved in the present disclosure is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by the combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features with similar functions disclosed in the present disclosure (but not limited to) can be used.

Claims

1. A method for manufacturing a composite copper foil, characterized by, The application relates to a manufacturing method of a composite copper foil. A base film is formed by attaching a polymer material to the surface of a quasi-base film formed by partially peeling off a copper film of the composite copper foil; A copper metal layer is deposited on the two side surfaces of the base film; The method for depositing the copper metal layer on the two side surfaces of the base film comprises: The copper metal layer is deposited on the two side surfaces of the base film by a magnetron sputtering process combined with a water electroplating process. The magnetron sputtering process comprises a preceding stage and a subsequent stage.

2. The method of manufacturing a composite copper foil according to claim 1, characterized by, The parameters of the magnetron sputtering process are adjusted according to the flatness of the surface of the thin film obtained in the preceding stage. The method is obtained by the manufacturing method of the composite copper foil according to any one of claims 1-2. The composite copper foil comprises: A first film layer made of a polymer material; 3. A composite copper foil, characterized by, A first copper film above the first film layer; 4. The composite copper foil according to claim 3, characterized by A second film layer made of a polymer material above the first copper film; A second copper film above the second film layer; A third copper film below the first film layer; The first film layer and the first copper film form the composite copper foil with the copper film partially peeled off; and the first film layer, the first copper film and the second film layer form the base film. The composite copper foil comprises: A first film layer made of a polymer material; A first copper film above the first film layer; 5. The composite copper foil according to claim 3, wherein A second copper film below the first film layer; A second film layer made of a polymer material above the first copper film and the second copper film; A third copper film above the second film layer; The first film layer, the first copper film and the second copper film form the composite copper foil with the copper film partially peeled off; and the first film layer, the first copper film, the second copper film and the second film layer form the base film. The first copper film is a continuous copper film or a discontinuous copper film. The first copper film is a continuous copper film or a discontinuous copper film; and / or the second copper film is a continuous copper film or a discontinuous copper film. The application relates to a composite copper foil.

6. The composite copper foil according to claim 4, wherein The composite copper foil is obtained by the manufacturing method according to any one of claims 3-7.

7. The composite copper foil according to claim 5, wherein ​ 8. A lithium-ion battery, characterized by, ​

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