Preparation method and production system of composite copper foil

Abstract

The invention relates to a preparation method and a production system of a composite copper foil. The method comprises the following steps: generating a copper foil on the surface of a cathode roller by adopting an electrolytic method; the supporting film is compounded on the surface of the copper foil in a rolling compounding mode, so that the first electrolytic copper foil containing the supporting film is prepared, and the supporting film is one or a combination of multiple of an electrostatic film and a glue film; stripping the first electrolytic copper foil containing the supporting film from the surface of the cathode roller; the first electrolytic copper foil containing the supporting film is taken and comprises a first copper foil and a first supporting film which are sequentially arranged in a stacked mode, the surface of the first copper foil is coated with glue, and a first adhesive layer is prepared; compositing the first electrolytic copper foil containing the supporting film on the first side surface of the macromolecular base film under the action of the first adhesive layer; stripping the first support film; wherein the binding force between the first supporting film and the first copper foil is F1, the binding force between the first adhesive layer and the first copper foil is F2, and F1 is smaller than F2. The method is simple to operate, good in compounding effect and low in process and equipment cost.

Description

Technical Field

[0001] This application relates to the field of composite material production technology, and more specifically, to a method for preparing composite copper foil and a production system. Background Technology

[0002] In recent years, the rapid development of 5G, consumer electronics, new energy vehicles, and energy storage has driven a rapid increase in the demand for metal foil, especially copper foil. Copper foil, a key material for the negative electrode current collector in lithium batteries, is mainly prepared by electrolytic deposition (ED) and rolling (RA). Electrolytic copper foil (ED copper foil) involves electrolytically depositing copper ions on the cathode, forming a green foil by controlling the current density and adding additives, and then surface-treating it (such as roughening and passivation) to create the finished product. It has advantages such as low cost, mature technology, and the ability to mass-produce ultra-thin copper foil with a thickness ≤6μm. Rolled copper foil (RA copper foil), on the other hand, is made by physically rolling high-purity copper ingots, followed by annealing and pickling processes. It has excellent ductility (e.g., elongation at break >10%), but its thickness is difficult to reduce to less than 6μm, resulting in high costs. Currently, electrolytic copper foil holds over 90% of the market share, dominating lithium battery applications.

[0003] The battery industry is currently moving towards thinner and more advanced designs. However, copper foil suffers from high production costs, high density, and a large weight percentage in batteries, leading to lower energy density. To address this, the industry has developed ultra-thin copper foil with a thickness of 4.5μm. However, as the thickness of the copper foil decreases further, its peelability significantly reduces, making it prone to tearing during the peeling process from the cathode roller surface.

[0004] In addition, to further reduce the proportion of copper foil in batteries and improve energy density, the industry has also developed current collectors composed of a polymer base film and metal foil layers disposed on one or both sides of the polymer base film, called composite current collectors, such as composite copper foil current collectors and composite aluminum foil current collectors. However, traditional composite copper foil is usually made by a "two-step" or "three-step" copper plating process. The "two-step" process first deposits a metal layer with a thickness of tens of nanometers on the surface of a polymer film by magnetron sputtering, making it conductive and ensuring that the film layer has good density and adhesion. Then, the metal layer is thickened to the target thickness, such as 1μm, by electroplating. The "three-step" process is based on the "two-step" process, adding vapor deposition before the electroplating process to accelerate the deposition of the metal layer. Both the "two-step" and "three-step" processes have problems such as complex and uncontrollable processes, poor uniformity of composite copper foil, high equipment cost, relatively simple equipment functions, high production costs, and difficulty in mass production. Summary of the Invention

[0005] Based on this, this application provides a new method and production system for preparing composite copper foil, which can simplify the composite production process, reduce costs, improve the peelability of ultrathin copper foil, ensure uniform and stable composite of composite copper foil, and have good performance.

[0006] The technical solution of this application is a method for preparing composite electrolytic copper foil, comprising the following steps:

[0007] S100: Copper foil is generated on the surface of the cathode roller by electrolysis;

[0008] S200: A support film is laminated onto the surface of the copper foil by a roll forming process to prepare a first electrolytic copper foil containing a support film, wherein the support film is one or more of an electrostatic film and an adhesive film.

[0009] S300: Peel the first electrolytic copper foil containing the support film from the surface of the cathode roller;

[0010] S400: Take the first electrolytic copper foil containing the support film, which includes a first copper foil and a first support film stacked in sequence, and apply adhesive to the surface of the first copper foil to prepare a first adhesive layer;

[0011] S500: Through the action of the first adhesive layer, the first electrolytic copper foil containing the support film is laminated onto the first side surface of the polymer base film;

[0012] S600: Peel off the first support membrane;

[0013] Wherein, the bonding force between the first supporting film and the first copper foil is F1, and the bonding force between the first adhesive layer and the first copper foil is F2, and F1 and F2 satisfy: F1 < F2. Further, F1 and F2 satisfy: F2 / F1 ≥ 1.5.

[0014] In one embodiment, F1 is 0.5N / 25mm to 1.0N / 25mm.

[0015] In one embodiment, F2 is 1.5N / 25mm to 5.0N / 25mm.

[0016] In one embodiment, the tensile strength of the support membrane is ≥150 MPa, the elongation at break is ≥80%, and the tensile strength corresponding to a constant elongation of 3% is ≥40 MPa.

[0017] In one embodiment, the thickness of the support film is 15 μm to 50 μm.

[0018] In one embodiment, the electrostatic film is made of one or more of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyurethane (PU), and ethylene-vinyl acetate copolymer (EVA).

[0019] In one embodiment, the adhesive film includes a substrate and an adhesive layer on the surface of the substrate, wherein the substrate is made of one or more of the following materials: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyimide (PI), polyamide (PA), polyester (PC), polyvinyl chloride (PVC), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polybutylene terephthalate (PBT), acrylonitrile-styrene copolymer (SAN), acrylonitrile-butadiene-styrene terpolymer (ABS), polyarylsulfone (PASF), polyethylene naphthalate (PEN), poly3,4-ethylenedioxythiophene (PEDOT), polyaniline (PANI), and polypyrrole (PPy); and the adhesive layer includes one or more of the following materials: rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, organosilicon polymers and their modified compounds, and polyolefins and their modified compounds.

[0020] In one embodiment, the thickness of the copper foil is 0.8 μm to 6 μm.

[0021] In one embodiment, the thickness of the polymer base film is 1 μm to 6 μm.

[0022] In one embodiment, the polymer base film is made of one or more of the following materials: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyimide (PI), polyamide (PA), polyester (PC), polyvinyl chloride (PVC), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polybutylene terephthalate (PBT), acrylonitrile-styrene copolymer (SAN), acrylonitrile-butadiene-styrene terpolymer (ABS), polyarylsulfone (PASF), polyethylene naphthalate (PEN), poly3,4-ethylenedioxythiophene (PEDOT), polyaniline (PANI), and polypyrrole (PPy).

[0023] In one embodiment, the thickness of the first adhesive layer is 0.2 μm to 4 μm.

[0024] In one embodiment, the first adhesive layer comprises one or more combinations of rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, silicone polymer and modified compounds thereof, and polyolefin and modified compounds thereof.

[0025] In one embodiment, the method for preparing the composite copper foil further includes: after step S300 and before step S400, performing passivation treatment and / or winding treatment on the electrolytic copper foil containing the support film.

[0026] In one embodiment, S400 further includes a step of performing a first heat treatment on the first adhesive layer.

[0027] In one embodiment, the method for preparing the composite copper foil further includes: after step S600, performing passivation treatment and / or winding treatment on the composite copper foil.

[0028] In one embodiment, the method for preparing the composite copper foil further includes the following steps:

[0029] A100: Repeat steps S100, S200 and S300 to prepare the second electrolytic copper foil containing the support film, which includes a second copper foil and a second support film stacked in sequence;

[0030] A200: Apply adhesive to the surface of the second copper foil to prepare a second adhesive layer;

[0031] A300: The second electrolytic copper foil containing the support film is laminated to the second side surface of the polymer base film through the action of the second adhesive layer;

[0032] A400: Peel off the second support membrane;

[0033] Wherein, the bonding force between the second support film and the second copper foil is F3, and the bonding force between the second adhesive layer and the second copper foil is F4, wherein F3 and F4 satisfy: F3 < F4. Further, F3 and F4 satisfy: F4 / F3 ≥ 1.5.

[0034] In one embodiment, F3 is 0.5N / 25mm to 1.0N / 25mm.

[0035] In one embodiment, F4 is 1.5N / 25mm to 5.0N / 25mm.

[0036] In one embodiment, the thickness of the second adhesive layer is 0.2 μm to 4 μm.

[0037] In one embodiment, the second adhesive layer comprises one or more of the following: rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, silicone polymer and modified compounds thereof, and polyolefin and modified compounds thereof.

[0038] In one embodiment, A200 further includes a step of heat-treating the second adhesive layer.

[0039] In one embodiment, the method for preparing the composite copper foil further includes: after step A400, performing passivation treatment and / or winding treatment on the composite copper foil after peeling off the second support film.

[0040] The present invention also provides a composite copper foil production system for implementing the method for preparing composite copper foil as described above, comprising:

[0041] A first electrolytic copper foil production system containing a support film includes: a first support film unwinding device for unwinding a first support film; a first foil production device including a first cathode roller for at least producing a first copper foil; and a first support film laminating device including a first laminating roller group that abuts against the first cathode roller for laminating the first support film and the first copper foil to obtain a first electrolytic copper foil containing a support film.

[0042] The first adhesive coating system is located downstream of the first electrolytic copper foil production system containing a support film, and includes a first adhesive coating device for coating the first copper foil with adhesive to prepare a first adhesive layer.

[0043] A base film unwinding system, used at least for unwinding polymer base films;

[0044] The first composite system, located downstream of the first coating system and the base film unwinding system, includes a first composite roller group for bonding a first electrolytic copper foil containing a support film and a first adhesive layer to a first side surface of the polymer base film.

[0045] A first support film peeling and winding device is located downstream of the first composite system and is used to peel and wind up the first support film.

[0046] Composite copper foil winding system for winding composite copper foil;

[0047] The polymer base film is transported at least in the path sequence of the base film unwinding system, the first composite system, and the composite copper foil winding system.

[0048] In one embodiment, the first electrolytic copper foil production system containing a support film further includes a first winding device located downstream of the first support film composite system for winding the first electrolytic copper foil containing a support film; the composite copper foil production system further includes a first unwinding system located upstream of the first coating system and on the first side of the polymer base film for unwinding the first electrolytic copper foil containing a support film.

[0049] In one embodiment, the first adhesive coating system further includes a first heating device located downstream of the first adhesive coating device and upstream of the first composite system, for performing a first heat treatment on the first adhesive layer.

[0050] In one embodiment, the composite copper foil production system further includes a composite copper foil passivation system located upstream of the composite copper foil winding system for passivating the composite copper foil. Further, the composite copper foil passivation system is located downstream of the first support film peeling and winding device.

[0051] In one embodiment, the composite copper foil production system described above further includes:

[0052] A second electrolytic copper foil production system containing a support film includes: a second support film unwinding device for unwinding a second support film; a second foil production device including a second cathode roller for at least producing a second copper foil; and a second support film laminating device including a second laminating roller group that abuts against the second cathode roller for laminating the second support film and the second copper foil to obtain a second electrolytic copper foil containing a support film.

[0053] The second coating system, located downstream of the second electrolytic copper foil production system containing the support film, includes a second coating device for coating the second copper foil with adhesive to prepare a second adhesive layer.

[0054] The second composite system is located downstream of the second coating system and the base film unwinding system and upstream of the first composite system. It includes a second composite roller group for bonding the second electrolytic copper foil containing the support film and the second adhesive layer to the second side surface of the polymer base film.

[0055] The second support film peeling and winding device is located downstream of the second composite system and upstream of the composite copper foil winding system, and is used to peel and wind the second support film.

[0056] The polymer base film is transported in at least the following path sequence: base film unwinding system, second composite system, first composite system, and composite copper foil winding system.

[0057] In one embodiment, the second electrolytic copper foil production system containing a support film further includes a second winding device located downstream of the second support film composite system for winding the second electrolytic copper foil containing a support film; the composite copper foil production system further includes a second unwinding system located upstream of the second coating system for unwinding the second electrolytic copper foil containing a support film.

[0058] In one embodiment, the second adhesive coating system further includes a second heating device located downstream of the second adhesive coating device and upstream of the second composite system, for performing a second heat treatment on the second adhesive layer.

[0059] In one embodiment, a buffer loop is provided between the first composite system and the second composite system to coordinate the linear speed and tension of each membrane material in the first composite system and the second composite system, so that each production line can operate continuously and stably.

[0060] In one embodiment, the second support film peeling and winding device is located upstream of the first composite system.

[0061] In one embodiment, both the first support film peeling and winding device and the second support film peeling and winding device are located downstream of the first composite system.

[0062] In one embodiment, the composite copper foil passivation system is located downstream of the second support film peeling and winding device.

[0063] In one embodiment, the first electrolytic copper foil production system containing a support film, the first adhesive coating device, the first heating device, and the first support film peeling and winding device are all located on the first side of the base film unwinding system; the second electrolytic copper foil production system containing a support film, the second adhesive coating device, the second heating device, and the second support film peeling and winding device are all located on the second side of the base film unwinding system.

[0064] In one embodiment, the first support film composite device and the first support film unwinding device are located on the same side of the first cathode roller, and the first winding device is located on the other side of the first cathode roller. The first electrolytic copper foil production system containing the support film also includes a first film material transfer roller located around the first support film unwinding device. The first electrolytic copper foil containing the support film forms a U-shaped transfer path around the first support film unwinding device on the first film material transfer roller, with the U-shaped opening facing the first winding device.

[0065] In one embodiment, the first electrolytic copper foil production system containing a support film further includes a first passivation device located downstream of the first support film composite device and upstream of the first winding device, for passivating the first electrolytic copper foil containing the support film.

[0066] In one embodiment, the second support film composite device and the second support film unwinding device are located on the same side of the second cathode roller, and the second winding device is located on the other side of the second cathode roller. The second electrolytic copper foil production system containing the support film also includes a second film material transfer roller located around the second support film unwinding device. The second electrolytic copper foil containing the support film forms a U-shaped transfer path around the second support film unwinding device on the second film material transfer roller, with the U-shaped opening facing the second winding device.

[0067] In one embodiment, the second electrolytic copper foil production system containing a support film further includes a second passivation device located downstream of the second support film composite device and upstream of the second winding device, for passivating the second electrolytic copper foil containing a support film.

[0068] This application includes at least the following beneficial effects:

[0069] For ultrathin copper foil, its peelability deteriorates significantly with decreasing thickness. Taking copper foil as an example, the mechanical strength of ultrathin copper foil (e.g., thickness ≤ 6 μm) is much lower than that of thick copper foil (e.g., thickness ≥ 35 μm). During peeling, the copper foil needs to withstand the tension at the peeling point on the roller surface and the traction force during subsequent transport. Ultrathin copper foil is prone to breakage or tearing due to stress concentration at the moment of peeling, leading to peeling failure. Furthermore, ultrathin copper foil may generate high internal stress during rapid deposition, and its grain size is relatively large relative to its thickness, resulting in reduced ductility and increased brittleness. In addition, although the cathode roller surface has been polished, it still has a certain degree of roughness. Ultrathin copper foil is more likely to embed into rough peaks and valleys, forming a mechanical interlocking effect and increasing peeling resistance. Thick copper foil, due to its high rigidity, is not easy to completely conform to the microscopic contour, and the interlocking effect is weaker.

[0070] This application employs an online lamination method to directly prepare electrolytic copper foil containing a support film on the surface of a cathode roller. The support film includes an electrostatic film and / or an adhesive film. The electrostatic film has electrostatic adsorption properties, while the adhesive film has adhesive properties. Combined with the roller lamination method, the support film and copper foil can be stably laminated together. Furthermore, compared to the bonding force between the copper foil and the cathode roller, the bonding force between the electrostatic film and the copper foil, or between the adhesive film and the copper foil, is stronger. After the support film and copper foil are bonded together as a whole, the thickness and / or strength increase, significantly improving the peelability of the ultra-thin copper foil. Peeling the electrolytic copper foil containing the support film as a whole from the surface of the cathode roller can effectively avoid defects such as tearing and breakage of the copper foil. The preparation process of this electrolytic copper foil containing a support film is simple and quick, requiring no complex and expensive production equipment, and is easy to industrialize.

[0071] Based on this, an adhesive layer is prepared by coating the copper foil surface. Utilizing the adhesive properties of the adhesive layer, a polymer base film can be directly and stably laminated with the surface of the electrolytic copper foil containing the support film to form a composite copper foil. This results in high composite strength and structural stability between the polymer base film and the copper foil. After lamination, the support film is then peeled off. Both the support film lamination process and the polymer base film lamination process, as well as the support film peeling process, offer advantages such as simplicity, speed, and ease of control. In particular, the polymer base film lamination process does not require the complex and expensive production equipment (such as sputtering and evaporation equipment) of traditional two-step or three-step methods, facilitating mass production and overcoming the problem of difficult mass production of composite copper foil. The resulting composite copper foil can be further used to prepare copper-clad laminates or composite current collectors, showing broad prospects. Attached Figure Description

[0072] Figure 1 This is a flowchart illustrating a method for preparing composite copper foil according to an embodiment of this application;

[0073] Figure 2 This is a schematic diagram of the structure of an electrolytic copper foil containing a support film according to an embodiment of this application;

[0074] Figure 3 This is a schematic diagram of the structure of a single-sided composite copper foil according to an embodiment of this application;

[0075] Figure 4 This is a schematic diagram of the structure of a double-sided composite copper foil according to an embodiment of this application;

[0076] Figure 5 This is a flowchart illustrating a method for preparing double-sided composite copper foil according to an embodiment of this application;

[0077] Figure 6 This is a flowchart illustrating a method for preparing double-sided composite copper foil according to another embodiment of this application;

[0078] Figure 7 This is a schematic diagram of a production system for preparing electrolytic copper foil containing a support film, according to an embodiment of this application.

[0079] Figure 8 This is a schematic diagram of the structure of a conventional foil-making equipment according to an embodiment of this application;

[0080] Figure 9 This is a schematic diagram of a production system for preparing electrolytic copper foil containing a support film, according to an embodiment of this application.

[0081] Figure 10 This is a schematic diagram of a production system for preparing electrolytic copper foil containing a support film, as shown in an embodiment of this application, illustrating the material feeding sequence during the preparation of the metal foil;

[0082] Figure 11This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0083] Figure 12 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0084] Figure 13 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0085] Figure 14 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0086] Figure 15 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0087] Figure 16 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0088] Figure 17 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0089] Figure 18 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0090] Figure 19 This is a schematic diagram of a production system for preparing composite copper foil according to an embodiment of this application;

[0091] Figure 20 Image of a double-sided composite copper foil prepared according to an embodiment of this application;

[0092] Explanation of reference numerals in the attached drawings: Electrolytic copper foil with supporting film ZB, copper foil 10, supporting film 20, first electrolytic copper foil with supporting film ZB-1, second electrolytic copper foil with supporting film ZB-2, first copper foil 10-1, second copper foil 10-2, first supporting film 20-1, second supporting film 20-2, first adhesive layer 30-1, second adhesive layer 30-2, foil production equipment / foil production device 1, cathode roller 11, first cathode roller 111, second cathode roller 112, electrolytic cell 12, first electrolytic cell 121, second electrolytic cell 122, supporting film unwinding device 100, first supporting film unwinding device 100-1, second supporting film unwinding device 100-2, supporting film composite device 2, first supporting film composite device 201 The following components are included: second support film composite device 202, guide roller 21, first guide roller 211, second guide roller 212, composite pressure roller 22, first composite roller group 221, second composite roller group 222, guide roller 23, first guide roller 231, second guide roller 232, film material transfer roller 3, film material transfer roller No. 1 31, film material transfer roller No. 2 32, passivation device 4, first passivation device 4-1, second passivation device 4-2, passivation groove 41, traction roller 42, passivation roller 43, squeeze roller 44, winding device 5, first winding device 5-1, second winding device 5-2, No. 1 winding tension roller 51, No. 2 winding tension roller 52, winding roller 53, copper foil peeling roller 13, copper foil passivation device 14, copper foil passivation groove 14. 01. Copper foil flattening roller 1402. First tension roller 1403. Copper foil passivation liquid lower roller 1404. Copper foil squeezing roller 1405. Copper foil drying oven 1406. Copper foil winding device 15. Copper foil winding and flattening roller 1501. Copper foil winding tension roller 1502. Copper foil winding transfer roller 1503. Copper foil winding roller 1504. Cleaning device 16. Polishing device 17. Single-sided composite copper foil DFB. Polymer base film 40. Double-sided composite copper foil SFB. Electrolytic copper foil production system with support film ZBS. First electrolytic copper foil production system with support film ZBS-1. Second electrolytic copper foil production system with support film ZBS-2. First unwinding system 1000. Transfer roller 1001. First coating system 2000. The system comprises a first adhesive coating device 2001, a first heating device 2002, a base film unwinding system 3000, a first composite system 4000, a first composite roller group 40011, a first support film peeling and winding device 501, a first support film peeling roller 5011, a first support film winding roller 5012, a second support film peeling and winding device 502, a second support film peeling roller 5021, a second support film winding roller 5022, a composite copper foil winding system 6000, a composite copper foil passivation system 7000, a second unwinding system 8000, a second adhesive coating system 9000, a second adhesive coating device 9001, a second heating device 2002, a second composite system 10000, a second composite roller group 10001, and a buffer loop 11000. Detailed Implementation

[0093] The technical solution of this application will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of this application, but not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. In addition, the drawings are not drawn to a 1:1 scale, and the relative dimensions of each element are drawn in the drawings only as examples to facilitate understanding of this application, but are not necessarily drawn to the actual scale. The scale in the drawings does not constitute a limitation on this application.

[0094] The specific embodiments and accompanying drawings described herein are for illustrative purposes only and should not be construed as limiting the scope of this application. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0095] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application and in its specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0096] In this application, "and / or" includes any and all combinations of one or more of the associated listed items. The terms "comprising," "having," and "including" as used in this application are intended to cover non-exclusive inclusion, unless explicit qualifying terms such as "only," "consisting of," etc., are used, in which case another component may be added.

[0097] In this application, terms such as "preferred," "more preferably," "preferably," and "even more preferably" refer to embodiments of this application that may provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, terms such as "preferred," "more preferably," "preferably," and "even more preferably" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application. Similarly, terms such as "further," "even more," and "particularly" are used only for descriptive purposes to indicate differences in content, but should not be construed as a limitation on the scope of protection of this application.

[0098] In this application, "A and B are independently selected from x, y or z" means that A and B are independent events, and event A does not affect the occurrence of event B. Therefore, when A is selected from x, B can be selected from any one of x, y or z; when A is selected from y, B can be selected from any one of x, y or z; when A is selected from z, B can be selected from any one of x, y or z.

[0099] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all subranges to which they are included.

[0100] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0101] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0102] In this application, room temperature refers to 0℃~60℃, including but not limited to 10℃~40℃, or further to 20℃~30℃.

[0103] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying a sequence, relative importance, or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0104] In this application, "multiple" or "several" means at least two, such as two, three, etc., unless otherwise expressly specified. "Several" means at least one, such as one, two, three, etc., unless otherwise expressly specified. "At least one" means any one, any two, or any two and more. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0105] In this application, directional terms such as "center," "lateral," "longitudinal," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this application.

[0106] In this application, when describing positional relationships, unless otherwise specified, when an element such as a layer, film, or substrate is referred to as being "on" another film layer, it may be directly on the other film layer or there may be intermediate film layers. Furthermore, when a layer is referred to as being "below" another layer, it may be directly below it or there may be one or more intermediate layers. It is also understood that when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or there may be one or more intermediate layers.

[0107] In this application, the viscosity of hydroxyethyl cellulose is the viscosity of a 2w% aqueous solution of the corresponding hydroxyethyl cellulose, measured at 25°C using a Brook viscometer, and the unit is mPa·s.

[0108] In this application, the test methods for tensile testing of materials (such as tensile strength and elongation at break) are well known to those skilled in the art, and this application does not limit them. For example, the test methods can refer to GB / T29847-2013, SJ / T 11483-2014, or GB / T 1040.3-2006. The test instrument can be a universal tensile testing machine (also known as a universal material testing machine or tensile testing machine) to test the tensile strength and elongation at break of the sample.

[0109] According to the general understanding in the electrolytic copper foil industry, conventional or standard copper foil has a thickness of 12μm or more, such as 18μm, 35μm, or 70μm, possessing both excellent mechanical properties and peelability. Thin copper foil has a thickness of 9μm to 12μm, increasing the difficulty of processing. Ultra-thin copper foil has a thickness of less than 9μm, with 6μm and 5μm copper foil being the main types, significantly increasing the difficulty of production, peeling, transport, and post-processing (such as surface treatment and lamination). Extremely thin copper foil has a thickness of less than 4.5μm, making production, peeling, transport, and post-processing (such as surface treatment and lamination) extremely difficult. Copper foil with a thickness of less than 3μm is usually difficult to peel off independently and requires a carrier.

[0110] With the development of lithium battery technology, high energy density, lightweight design, battery safety, and reduced battery costs have become the focus of lithium battery manufacturers' efforts. Traditional lithium batteries use electrolytic copper foil as the negative electrode current collector. Currently, the mainstream electrolytic copper foil on the market has a thickness of ≥6μm, a tensile strength of ≥330MPa, and an elongation at break of 3.0%~4.0%. Some companies have developed copper foil with a thickness of 4.5μm, a tensile strength of 280MPa~380MPa, and an elongation at break of 3.0%~4.0% (understandably, the data may vary slightly due to different testing standards and conditions). As the thickness of the copper foil decreases further, its mechanical properties drop significantly. During peeling, the copper foil needs to withstand the tension at the peeling point on the roller surface and the traction force during subsequent transport. Ultra-thin copper foil is prone to breakage or tearing due to stress concentration at the moment of peeling, leading to peeling failure. Furthermore, although the cathode roller surface is usually polished, microscopic roughness still exists. Ultra-thin copper foil is more likely to embed into rough peaks and valleys, forming a mechanical interlocking effect and increasing peeling resistance. Furthermore, thin copper foils have short deposition times and narrow process windows, which can generate high internal stress during rapid deposition. Relative to their thickness, the grain size is larger, reducing ductility and increasing brittleness. Simultaneously, fluctuations in electrolyte composition, current density, and temperature can easily lead to uneven deposition layer structure (such as coarse crystals or abnormal local stress), resulting in significant differences in local adhesion and easy breakage during peeling. Therefore, the tearing problem becomes increasingly severe as the copper foil thickness decreases. Traditional methods to address copper foil tearing involve complex pretreatment of the cathode or structural modification, such as using special coatings (e.g., chromium, ceramic) to reduce adhesion while maintaining a smooth surface; modifying the anode; or altering the electrolyte additive composition. These methods are either cumbersome, have high equipment costs, poor electrolyte suitability, or difficult-to-control electrolysis parameters, resulting in unstable copper foil performance and large batch-to-batch variations, making industrialization difficult.

[0111] In addition, to further reduce the use of copper foil, effectively lower the cost of battery current collectors, and improve the overall energy density and safety of batteries, the industry has developed current collectors composed of a polymer base film and metal foil layers disposed on one or both sides of the polymer base film, called composite current collectors, such as composite copper foil current collectors. Traditional composite copper foil is usually made by a "two-step" or "three-step" copper plating process. Both the "two-step" and "three-step" methods have problems such as complex and uncontrollable processes, poor uniformity of composite copper foil, high equipment costs, relatively simple equipment functions, high production costs, and difficulty in mass production, which urgently need to be improved.

[0112] To solve the above problem, see Figure 1 One embodiment of this application provides a method for preparing composite copper foil, comprising the following steps:

[0113] S100: Copper foil 10 is generated on the surface of cathode roller 11 by electrolysis;

[0114] S200: The support film 20 is laminated onto the surface of the copper foil 10 by a roll forming process to prepare the first electrolytic copper foil ZB-1 containing the support film, wherein the support film 20 is one or more of an electrostatic film and an adhesive film.

[0115] S300: Peel the first electrolytic copper foil ZB-1 containing the support film from the surface of the cathode roller 11;

[0116] S400: Take the first electrolytic copper foil ZB-1 containing the support film, which includes a first copper foil 10-1 and a first support film 20-1 stacked in sequence, and apply adhesive to the surface of the first copper foil 10-1 to prepare a first adhesive layer 30-1.

[0117] S500: Through the action of the first adhesive layer 30-1, the first electrolytic copper foil ZB-1 containing the support film is laminated onto the first side surface of the polymer base film 40;

[0118] S600: Peel off the first support membrane 20-1;

[0119] Wherein, the bonding force between the first support film 20-1 and the first copper foil 10-1 is F1, and the bonding force between the first adhesive layer 30-1 and the first copper foil 10-1 is F2. F1 and F2 satisfy: F1 < F2.

[0120] This application employs an online lamination method to directly prepare an electrolytic copper foil ZB containing a support film on the surface of a cathode roller 11. The support film 20 comprises an electrostatic film and / or an adhesive film. The electrostatic film has electrostatic adsorption properties, and the adhesive film has adhesive properties. Combined with the roller lamination method, the support film 20 and the copper foil 10 can be stably laminated together. Furthermore, compared to the bonding force between the copper foil 10 and the cathode roller 11, the bonding force between the electrostatic film and the copper foil, or between the adhesive film and the copper foil, is stronger. After the support film 20 and the copper foil 10 are bonded together as a whole, the thickness and / or strength increase, significantly improving the peelability of the ultra-thin copper foil. Peeling the electrolytic copper foil ZB containing the support film as a whole from the surface of the cathode roller 11 can effectively avoid defects such as copper foil tearing and breakage. The preparation process of this electrolytic copper foil ZB containing the support film is simple and quick, requires no complex and expensive production equipment, and is easy to industrialize. Based on this, an adhesive layer 30 is prepared by coating the surface of copper foil 10 with adhesive. Utilizing the adhesive properties of the adhesive layer 30, the polymer base film 40 can be directly and uniformly laminated onto the surface of the electrolytic copper foil ZB containing the support film to form a composite copper foil. This results in high composite strength and structural stability between the polymer base film 40 and the copper foil 10. After lamination, the support film is then peeled off. Whether it is the support film lamination process, the polymer base film lamination process, or the support film peeling process, it has the advantages of simple operation, speed, and easy control. In particular, the polymer base film lamination process does not require the complex and expensive production equipment of the traditional two-step or three-step method, which facilitates mass production and overcomes the problem of difficult mass production of composite copper foil.

[0121] See Figure 2 ,according to Figure 1 The electrolytic copper foil ZB containing a support film prepared by the method shown includes copper foil 10 and support film 20 stacked sequentially.

[0122] See Figure 3 ,according to Figure 1 The method shown illustrates the preparation of a single-sided composite copper foil (DFB), comprising a copper foil 10, a first adhesive layer 30-1, and a polymer base film 40 sequentially stacked. Additionally, the surface of the copper foil 10 can be passivated as needed to prepare a passivation layer. (Repeat) Figure 1 The steps shown in the preparation of adhesive layer 30 (e.g., labeled as second adhesive layer 30-2) and composite polymer base film 40 with copper foil 10 can be used to prepare... Figure 4 The double-sided composite copper foil (SFB) shown includes a first copper foil 10-1, a first adhesive layer 30-1, a polymer base film 40, a second adhesive layer 30-2, and a second copper foil 10-2, which are sequentially stacked. Similarly, the surfaces of the first copper foil 10-1 and / or the second copper foil 10-2 can be passivated as needed to prepare a first passivation layer and a second passivation layer, respectively.

[0123] Understandably, for ease of understanding, the following description distinguishes the electrolytic copper foil ZB containing the supporting film used in the two processes according to the needs of preparing single-sided composite copper foil (DFB) and double-sided composite copper foil (SFB). For example, the electrolytic copper foil ZB containing the supporting film used in preparing single-sided composite copper foil (DFB) is the first electrolytic copper foil ZB-1 containing the supporting film, which includes a first copper foil 10-1 and a first supporting film 20-1 stacked sequentially. Similarly, the other electrolytic copper foil ZB containing the supporting film used in preparing double-sided composite copper foil (SFB) is the second electrolytic copper foil ZB-2 containing the supporting film, which includes a second copper foil 10-2 and a second supporting film 20-2 stacked sequentially. The first electrolytic copper foil ZB-1 containing the supporting film and the second electrolytic copper foil ZB-2 containing the supporting film may be the same or different. The copper foil 10 described in this application includes a first copper foil 10-1 and a second copper foil 10-2. The definition of the first copper foil 10-1 and the second copper foil 10-2 is directly referenced to the copper foil 10. However, the first copper foil 10-1 and the second copper foil 10-2 are independent of each other and may be the same or different in specific embodiments, such as having the same or different thicknesses. Similarly, the support film 20 described in this application includes a first support film 20-1 and a second support film 20-2. The definition of the first support film 20-1 and the second support film 20-2 is directly referenced to the support film 20. However, the first support film 20-1 and the second support film 20-2 are independent of each other and may be the same or different in specific embodiments, such as having the same or different thicknesses and materials.

[0124] In one embodiment, F2 / F1 ≥ 1.5, which facilitates the smooth progress of step S600, peeling off the first support membrane 20-1. Understandably, the ratio of F2 / F1 includes, but is not limited to, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Further, F2 / F1 ≥ 2. Even further, F2 / F1 is 2 to 5.

[0125] Furthermore, F2 is 1.5N / 25mm to 5.0N / 25mm, which facilitates the smooth peeling of the first support film 20-1 by S600. Understandably, F2 includes, but is not limited to: 1.5N / 25mm, 1.6N / 25mm, 1.8N / 25mm, 2.0N / 25mm, 2.1N / 25mm, 2.4N / 25mm, 2.5N / 25mm, 2.7N / 25mm, 3.0N / 25mm, 3.2N / 25mm, 3.5N / 25mm, 3.6N / 25mm, 3.9N / 25mm, 4.0N / 25mm, 4.2N / 25mm, 4.5N / 25mm, 4.8N / 25mm, or 5.0N / 25mm.

[0126] In one embodiment, F1 is 0.5N / 25mm to 1.0N / 25mm. Thus, the first support film 20-1 can be temporarily and effectively bonded to the surface of the first copper foil 10-1, which facilitates the smooth online peeling of the first copper foil 10-1 in step S300 and improves the transport stability of the first electrolytic copper foil ZB-1 containing the support film. It also facilitates the smooth peeling of the first support film 20-1 in step S600. Understandably, F1 includes, but is not limited to, 0.5N / 25mm, 0.6N / 25mm, 0.7N / 25mm, 0.8N / 25mm, 0.9N / 25mm, or 1.0N / 25mm.

[0127] In one embodiment, the thickness of the support film 20 (such as the first support film 20-1 or the second support film 20-2) is 15μm to 50μm. In this way, the support film 20 can be temporarily and effectively bonded to the surface of the copper foil 10, which is beneficial to the smooth progress of the online stripping of the copper foil 10 in S300 and to improve the transmission stability of the electrolytic copper foil ZB containing the support film. Understandably, the thickness of the support film 20 includes, but is not limited to, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, or 50μm.

[0128] In one embodiment, the tensile strength of the support film 20 (such as the first support film 20-1 or the second support film 20-2) is ≥150 MPa. This facilitates the smooth progress of the online copper foil stripping step 10 in S300 and improves the transport stability of the electrolytic copper foil ZB containing the support film. Further, the tensile strength of the support film 20 is 200 MPa to 350 MPa, including but not limited to: 200 MPa, 210 MPa, 230 MPa, 250 MPa, 280 MPa, 290 MPa, 300 MPa, 320 MPa, or 350 MPa.

[0129] In one embodiment, the elongation at break of the support film 20 (such as the first support film 20-1 or the second support film 20-2) is ≥80%. This facilitates the smooth progress of the online copper foil stripping step 10 in S300 and improves the transport stability of the electrolytic copper foil ZB containing the support film. Further, the elongation at break of the support film 20 is 80%~450%, including but not limited to: 80%, 90%, 100%, 120%, 150%, 180%, 200%, 220%, 250%, 300%, 350%, 400%, or 450%.

[0130] In one embodiment, the supporting film 20 (such as the first supporting film 20-1 or the second supporting film 20-2) has a tensile strength ≥ 40 MPa at a constant elongation of 3%. This facilitates the smooth progress of the online copper foil peeling step 10 in S300 and improves the transport stability of the electrolytic copper foil ZB containing the supporting film. It is understood that the tensile strength of the supporting film 20 at a constant elongation of 3% includes, but is not limited to, 40 MPa, 50 MPa, 80 MPa, 90 MPa, 100 MPa, 110 MPa, 120 MPa, 130 MPa, 140 MPa, or 150 MPa.

[0131] In one embodiment, the support film 20 is an electrostatic film, and its material is one or more combinations of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyurethane (PU), and ethylene-vinyl acetate copolymer (EVA). Exemplarily, the electrostatic film is made of polyethylene (PE) or polyvinyl chloride (PVC).

[0132] In one embodiment, the support film 20 is an adhesive film, which includes a substrate and an adhesive layer on the surface of the substrate. The substrate is made of one or more of the following materials: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyimide (PI), polyamide (PA), polyester (PC), polyvinyl chloride (PVC), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polybutylene terephthalate (PBT), acrylonitrile-styrene copolymer (SAN), acrylonitrile-butadiene-styrene terpolymer (ABS), polyarylsulfone (PASF), polyethylene naphthalate (PEN), poly3,4-ethylenedioxythiophene (PEDOT), polyaniline (PANI), and polypyrrole (PPy). The adhesive layer on the surface of the substrate includes one or more of the following materials: rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, organosilicon polymers and their modified compounds, and polyolefins and their modified compounds. Furthermore, the thickness of the substrate is 14.1μm~49.9μm, and the thickness of the adhesive layer is 0.1μm~25.9μm.

[0133] For example, the adhesive film is a PET adhesive film or a PP adhesive film, the substrate is PET or PP, and the thickness is 14.1μm to 49.9μm; the adhesive layer includes one or more of polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin and polyester resin, and the thickness is 0.1μm to 25.9μm.

[0134] Referring to the above, this application utilizes a support film 20 to online peel off the copper foil 10 from the surface of the cathode roller 11, which can significantly improve the peelability of the copper foil 10, especially the peelability of ultra-thin copper foil. Optionally, the thickness of the copper foil 10 (such as the first copper foil 10-1 or the second copper foil 10-2) is 0.8 μm to 6.0 μm, including but not limited to 0.8 μm, 0.85 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, etc. The thicknesses are 2.1 μm, 2.2 μm, 2.3 μm, 2.4 μm, 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3.0 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm, 3.5 μm, 4.0 μm, 4.5 μm, 4.8 μm, 5.0 μm, 5.2 μm, 5.5 μm, or 6.0 μm. Furthermore, this application can significantly improve the peelability of extremely thin copper foils. Exemplarily, the thickness of the copper foil 10 is 0.8 μm to 3.5 μm, and more specifically, 0.8 μm to 2.0 μm.

[0135] In one embodiment, before step S500, S400 further includes a step of performing a first heat treatment on the first adhesive layer 30-1. This can improve the adhesiveness of the first adhesive layer 30-1, thereby improving the composite effect. Optionally, the temperature of the first heat treatment is 40℃~100℃. Further, the first heat treatment is performed by first gradually increasing the temperature and then gradually decreasing it.

[0136] Referring to the above, the main difference between preparing double-sided composite copper foil SFB and preparing single-sided composite copper foil DFB is that it requires preparing or unwinding electrolytic copper foil ZB containing a support film twice, applying adhesive to prepare adhesive layer 30, and then compositing it with polymer base film 40 (which can be regarded as two compositings) and peeling and rewinding the support film 20 twice.

[0137] In one embodiment, the method for preparing the composite copper foil further includes the following steps:

[0138] A100: Repeat steps S100, S200 and S300 to prepare the second electrolytic copper foil ZB-2 containing the support film, which includes a second copper foil 10-2 and a second support film 20-2 stacked in sequence.

[0139] A200: Apply adhesive to the surface of the second copper foil 10-2 to prepare the second adhesive layer 30-2;

[0140] A300: Through the action of the second adhesive layer 30-2, the second electrolytic copper foil ZB-2 containing the support film is laminated to the second side surface of the polymer base film 40;

[0141] A400: Peel off the second support membrane 20-2;

[0142] Wherein, the bonding force between the second support film 20-2 and the second copper foil 10-2 is F3, and the bonding force between the second adhesive layer 30-2 and the second copper foil 10-2 is F4, and F3 and F4 satisfy: F3 < F4.

[0143] The descriptions of F3 and F4 are similar to those of F1 and F2 above. For example, F4 / F3 ≥ 1.5, which facilitates the smooth progress of step 20-2 of A400 peeling off the second support membrane. Understandably, the ratio of F4 / F3 can be, but is not limited to, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, or 10. Further, F4 / F3 ≥ 2. Even further, F4 / F3 can be 2 to 5.

[0144] Furthermore, F4 is 1.5N / 25mm to 5.0N / 25mm, which facilitates the smooth peeling of the second support film 20-2 by A400. Understandably, F4 includes, but is not limited to: 1.5N / 25mm, 1.6N / 25mm, 1.8N / 25mm, 2.0N / 25mm, 2.1N / 25mm, 2.4N / 25mm, 2.5N / 25mm, 2.7N / 25mm, 3.0N / 25mm, 3.2N / 25mm, 3.5N / 25mm, 3.6N / 25mm, 3.9N / 25mm, 4.0N / 25mm, 4.2N / 25mm, 4.5N / 25mm, 4.8N / 25mm, or 5.0N / 25mm.

[0145] In one embodiment, F3 is 0.5N / 25mm to 1.0N / 25mm. Thus, the second support film 20-2 can be temporarily and effectively bonded to the surface of the second copper foil 10-2, facilitating the smooth progress of the S300 step of peeling off the second copper foil 10-2 and improving the transport stability of the second electrolytic copper foil ZB-2 containing the support film. It also facilitates the smooth progress of the A400 step of peeling off the second support film 20-2. Understandably, F3 includes, but is not limited to, 0.5N / 25mm, 0.6N / 25mm, 0.7N / 25mm, 0.8N / 25mm, 0.9N / 25mm, or 1.0N / 25mm.

[0146] Understandably, this application does not impose any particular restrictions on the preparation of the first electrolytic copper foil ZB-1 with a support film and the second electrolytic copper foil ZB-2 with a support film, the preparation of the first adhesive layer 30-1 and the second adhesive layer 30-2, or the peeling order of the first support film 20-1 and the second support film 20-2. For example, the first support film 20-1 can be peeled off after the first round of composite preparation of single-sided composite copper foil DFB; or after the second round of composite preparation of double-sided composite copper foil SFB, the first support film 20-1 and the second support film 20-2 can be peeled off simultaneously or in stages. Optionally, steps A100, A200, A300 and A400 are all after step S500; or steps A100, A200 and A300 are all before step S500, and step A400 is either before or after step S500.

[0147] Furthermore, referring to the advantages of the first heat treatment described above, in one embodiment, before step A300, A200 further includes a step of performing a second heat treatment on the second adhesive layer 30-2. This can improve the adhesiveness of the second adhesive layer 30-2, thereby enhancing the composite effect. Optionally, the temperature of the second heat treatment is 40℃~100℃. Further, the second heat treatment is performed by first gradually increasing the temperature and then gradually decreasing it.

[0148] See Figure 5 One embodiment of this application provides a method for preparing such... Figure 4 The method for preparing double-sided composite copper foil (SFB) includes the following steps:

[0149] S100: Copper foil 10 is generated on the surface of cathode roller 11 by electrolysis;

[0150] S200: The support film 20 is laminated onto the surface of the copper foil 10 by a roll forming process to prepare the first electrolytic copper foil ZB-1 containing the support film, wherein the support film 20 is one or more of an electrostatic film and an adhesive film.

[0151] S300: Peel the first electrolytic copper foil ZB-1 containing the support film from the surface of the cathode roller 11;

[0152] S400: Take the first electrolytic copper foil ZB-1 containing the support film, which includes a first copper foil 10-1 and a first support film 20-1 stacked in sequence; apply adhesive to the surface of the first copper foil 10-1 to prepare a first adhesive layer 30-1; and perform a first heat treatment on the first adhesive layer 30-1.

[0153] S500: Through the action of the first adhesive layer 30-1, the first electrolytic copper foil ZB-1 containing the support film is laminated to the first side surface of the polymer base film 40 to prepare a single-sided composite copper foil intermediate; it can be understood that the first copper foil 10-1 is close to the polymer base film 40, and the first support film 20-1 is far away from the polymer base film 40.

[0154] S600: Peel off the first support film 20-1; wherein, the bonding force between the first support film 20-1 and the first copper foil 10-1 is F1, and the bonding force between the first adhesive layer 30-1 and the first copper foil 10-1 is F2, and F1 and F2 satisfy: F1 < F2.

[0155] A100: Repeat steps S100, S200 and S300 to prepare the second electrolytic copper foil ZB-2 containing the support film, which includes a second copper foil 10-2 and a second support film 20-2 stacked in sequence.

[0156] A200: Apply adhesive to the surface of the second copper foil 10-2 to prepare a second adhesive layer 30-2; subject the second adhesive layer 30-2 to a second heat treatment;

[0157] A300: Through the action of the second adhesive layer 30-2, the second electrolytic copper foil ZB-2 containing the support film is laminated to the second side surface of the polymer base film 40 to prepare a double-sided composite copper foil intermediate; it can be understood that the second copper foil 10-2 is close to the polymer base film 40, and the second support film 20-2 is far away from the polymer base film 40.

[0158] A400: Peel off the second support film 20-2; wherein, the bonding force between the second support film 20-2 and the second copper foil 10-2 is F3, and the bonding force between the second adhesive layer 30-2 and the second copper foil 10-2 is F4, and F3 and F4 satisfy: F3 < F4.

[0159] See Figure 6 One embodiment of this application provides another preparation method as follows: Figure 4 The method for double-sided composite copper foil (SFB) shown includes the following steps:

[0160] S100: Copper foil 10 is generated on the surface of cathode roller 11 by electrolysis;

[0161] S200: The support film 20 is laminated onto the surface of the copper foil 10 by a roll forming process to prepare the first electrolytic copper foil ZB-1 containing the support film, wherein the support film 20 is one or more of an electrostatic film and an adhesive film.

[0162] S300: Peel the first electrolytic copper foil ZB-1 containing the support film from the surface of the cathode roller 11;

[0163] A100: Repeat steps S100, S200 and S300 to prepare the second electrolytic copper foil ZB-2 containing the support film, which includes a second copper foil 10-2 and a second support film 20-2 stacked in sequence.

[0164] A200: Apply adhesive to the surface of the second copper foil 10-2 to prepare the second adhesive layer 30-2;

[0165] A300: The second electrolytic copper foil ZB-2 containing the support film is laminated to the second side surface of the polymer base film 40 through the second adhesive layer 30-2 to prepare a double-sided composite copper foil intermediate; it can be understood that the second copper foil 10-2 is close to the polymer base film 40, and the second support film 20-2 is far away from the polymer base film 40.

[0166] S400: Take the first electrolytic copper foil ZB-1 containing the support film, which includes a first copper foil 10-1 and a first support film 20-1 stacked in sequence, and apply adhesive to the surface of the first copper foil 10-1 to prepare a first adhesive layer 30-1.

[0167] S500: Through the action of the first adhesive layer 30-1, the first electrolytic copper foil ZB-1 containing the support film is laminated onto the first side surface of the polymer base film 40;

[0168] S600 / A400: Peel off the first support film 20-1 and the second support film 20-2; wherein, the bonding force between the first support film 20-1 and the first copper foil 10-1 is F1, the bonding force between the first adhesive layer 30-1 and the first copper foil 10-1 is F2, and F1 and F2 satisfy: F1 < F2; the bonding force between the second support film 20-2 and the second copper foil 10-2 is F3, the bonding force between the second adhesive layer 30-2 and the second copper foil 10-2 is F4, and F3 and F4 satisfy: F3 < F4.

[0169] Understandably, to improve the composite effect, roll forming can also be added in step S500, whereby the polymer base film 40 is laminated onto the surface of the first copper foil 10-1 of the first electrolytic copper foil ZB-1 containing the first supporting film as described above, through a combination of roll forming and adhesive bonding. Step A300 is similar.

[0170] Understandably, copper foil is prone to oxidation. To improve the oxidation resistance of the electrolytic copper foil ZB with a supporting film and the composite copper foil, optionally, the electrolytic copper foil ZB with a supporting film is passivated after step S300 and before step S400. Similarly, optionally, in Figure 1 Following step S600, the single-sided composite copper foil DFB is passivated. Similarly, optionally, in Figure 5Following step S600, the single-sided composite copper foil DFB is passivated, and then... Figure 5 Following step A400, the double-sided composite copper foil (SFB) is passivated. Similarly, optionally, in... Figure 6 After step S600 / A400 shown, the double-sided composite copper foil SFB is passivated.

[0171] Furthermore, it is understood that in this application, the electrolytic copper foil ZB containing the support film peeled off from the surface of the cathode roller 11 can ① be directly transferred downstream to be laminated with the polymer base film 40; or ② be first wound up, then unwound and laminated; this application does not impose any special restrictions on this. For the scheme of directly transferring the electrolytic copper foil ZB containing the support film peeled off from the surface of the cathode roller 11 to be laminated with the polymer base film 40 downstream, it can reduce process and copper foil loss. For the scheme of first winding the electrolytic copper foil ZB containing the support film and then unwinding, it is beneficial to reduce the difficulty of equipment layout and make it easier to control the line speed of each functional area, thereby reducing subsequent shrinkage or empty lamination of the laminated copper foil.

[0172] In one embodiment, the polymer base film 40 is made of one or more of the following materials: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyimide (PI), polyamide (PA), polyester (PC), polyvinyl chloride (PVC), polystyrene (PS), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polybutylene terephthalate (PBT), acrylonitrile-styrene copolymer (SAN), acrylonitrile-butadiene-styrene terpolymer (ABS), polyarylsulfone (PASF), polyethylene naphthalate (PEN), poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), and polypyrrole (PPy). Further, the polymer base film 40 is made of one or more of PET, PP, and PI. Even further, the polymer base film 40 is made of one or more of PET and PP. Exemplarily, the polymer base film 40 is made of PET.

[0173] In one embodiment, the thickness of the polymer base film 40 is 1 μm to 6 μm, including but not limited to: 1 μm, 1.9 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, or 6 μm. Further, the thickness of the polymer base film 40 is independently 1.9 μm to 5 μm.

[0174] In one embodiment, the thicknesses of the first adhesive layer 30-1 and the second adhesive layer 30-2 are independently 0.2 μm to 4 μm, including but not limited to: 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, 0.6 μm, 0.7 μm, 0.75 μm, 0.8 μm, 0.85 μm, 0.9 μm, 1 μm, 1.9 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, or 4 μm. Further, the thicknesses of the first adhesive layer 30-1 and the second adhesive layer 30-2 are independently 0.2 μm to 2 μm.

[0175] In one embodiment, the first adhesive layer 30-1 and the second adhesive layer 30-2 each independently comprise one or more combinations of rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, silicone polymer and its modified compounds, and polyolefin and its modified compounds. Exemplarily, the first adhesive layer 30-1 and the second adhesive layer 30-2 are cured from a polyurethane adhesive.

[0176] For example, the electrolytic copper foil containing the supporting film described in this application can be adopted. Figure 7 The electrolytic copper foil production system with a supporting film shown is prepared by ZBS. The production system includes:

[0177] Support film unwinding device 100, used for unwinding support film 20;

[0178] The foil forming apparatus 1 includes an electrolytic cell 12 and a cathode roller 11, wherein the electrolytic cell 12 is used to contain an electrolyte, and the bottom of the cathode roller 11 can be immersed in the electrolyte to form a copper foil 10 on the surface of the cathode roller 11.

[0179] The support film laminating device 2 includes a guide roller 21, a laminating pressure roller 22, and a guide roller 23. The guide roller 21 is located downstream of the support film unwinding device 100 and upstream of the laminating pressure roller 22, and is used to pull the unwound support film 10 to the surface of the cathode roller 11. The laminating pressure roller 22 and the cathode roller 11 abut against each other and are used to laminate the support film 20 and the copper foil 10 to obtain an electrolytic copper foil ZB containing the support film. The guide roller 23 is located downstream of the laminating pressure roller 22 and is used to peel the electrolytic copper foil ZB containing the support film from the surface of the cathode roller 11.

[0180] Several film material conveying rollers 3 are located downstream of the supporting film composite device 2, and are used at least to convey electrolytic copper foil ZB containing the supporting film to the downstream for winding or composite with polymer base film 40.

[0181] In addition, as described above, this application can choose to first wind up the electrolytic copper foil ZB containing the support film, and then perform unwinding and lamination operations. This helps to reduce the difficulty of equipment layout and makes it easier to control the production line speed of each functional area, thereby reducing the shrinkage or empty lamination of the composite copper foil.

[0182] See Figure 7 The production system ZBS for electrolytic copper foil ZB containing a support film further includes: a winding device 5, located downstream of the support film composite device 2, for winding the electrolytic copper foil ZB containing the support film, and the winding device 5 and the support film composite device 2 are located on the same side of the cathode roller 11. See also Figure 7 According to the direction of membrane material transport, the winding device 5 includes a No. 1 winding tension roller 51, a No. 2 winding tension roller 52, and a winding roller 53 in sequence.

[0183] Understandably, copper foil is prone to oxidation; see [reference needed]. Figure 7 The ZBS production system for electrolytic copper foil ZB containing a support film further includes: a passivation device 4, located downstream of the support film composite device 2 and upstream of the winding device 5, for passivating the electrolytic copper foil ZB containing the support film. See also Figure 7 The passivation device 4 includes a passivation tank 41, a traction roller 42, a passivation roller 43, and a squeeze roller 44.

[0184] Furthermore, it is understood that this application does not impose any special limitations on the foil-making apparatus 1. Existing foil-making equipment technology is known to be mature, and its structure is as follows: Figure 8As shown, the copper foil production equipment 1 mainly includes a cathode roller 11, an electrolytic cell 12 (optionally, some electrolytic cells 12 are buried underground), a copper foil stripping roller 13, a copper foil passivation device 14, a copper foil passivation tank 1401, a copper foil flattening roller 1402, a copper foil tension roller 1403, a copper foil passivation liquid roller 1404, a copper foil squeezing roller 1405, a copper foil drying box 1406, a copper foil winding device 15, a copper foil winding flattening roller 1501, a copper foil winding tension roller 1502, a copper foil winding guide roller 1503, and a copper foil winding roller 1504. Understandably, the downstream of the copper foil stripping roller 13, such as the copper foil passivation device 14 and the copper foil winding device 15, can be considered as the post-processing side. The electrolytic cell 12 is used to contain the electrolyte. The bottom of the cathode roller 11 can be immersed in the electrolyte to form copper foil on the surface of the cathode roller 11. The copper foil is peeled off from the surface of the cathode roller 11 by the copper foil peeling roller 13 and transferred to the downstream copper foil passivation device 14. The copper foil passivation tank 1401 is filled with passivation liquid. The copper foil is transferred to the copper foil passivation tank 1401 by the copper foil flattening roller 1402, the first tension roller 1403 and the copper foil passivation liquid lower roller 1404. The copper foil is immersed in the passivation liquid for passivation treatment. Then, the passivation liquid is removed by the copper foil squeezing roller 1405 and it enters the copper foil drying box 1406 for drying. The passivated copper foil enters the copper foil winding device 15. Specifically, the passivated and dried copper foil is transferred to the copper foil winding roller 1504 for winding by the copper foil winding flattening roller 1501, the copper foil winding tension roller 1502 and the copper foil winding over roller 1503. Further, see Figure 8 The foil production equipment 1 may also include a cleaning device 16, mainly comprising an acid-extrusion roller, a spray roller, and an air shower pipe (not specifically shown in the figure). The acid-extrusion roller, spray roller, and air shower pipe are arranged circumferentially around the cathode roller 11 and distributed sequentially from low to high along the direction away from the bottom of the electrolytic cell 12, mainly used to improve the cleanliness of the copper foil surface. In addition, the foil production equipment 1 may also include a polishing device 17 for polishing the surface of the cathode roller 11.

[0185] For example, see Figure 9 This application can directly use existing foil-making equipment 1 as the foil-making device 1 in the production system ZBS for preparing electrolytic copper foil with a support film. The copper foil peeling roller 13 and the composite pressure roller 22 are arranged circumferentially along the cathode roller 11 and are respectively located on both sides of the cathode roller 11. Furthermore, the copper foil passivation device 14 and the copper foil winding device 15 are located on the same side of the cathode roller 11 as the copper foil peeling roller 13. This production system can achieve integrated foil making and composite processes, and can be used to prepare both metallic copper foil and the electrolytic copper foil ZB with a support film described in this application, further reducing equipment costs and floor space, and improving the utilization rate of existing equipment. Specifically, on the one hand, see... Figure 10The ZBS electrolytic copper foil production system with a support film can produce metal foil independently using existing foil-making equipment 1, and perform conventional passivation and winding processes according to the original method and transport route, without being affected by the support film unwinding device 100 and the support film composite device 2. For thicker copper foil, its mechanical properties and peelability are better, and it can be completely peeled off from the surface of the cathode roller 11 directly by the copper foil peeling roller 13. On the other hand, see... Figure 9 The ZBS electrolytic copper foil production system containing the support film can also use the existing foil production equipment 1 and the support film unwinding device 100 and support film composite device 2 of this application to prepare composite copper foil. Through the action of the support film 20, the peelability of the metal copper foil is significantly improved. For extremely thin metal foils (such as 1μm copper foil) with poor mechanical properties and extremely difficult to peel, after being composited with the support film 20 and then peeled off as a whole, the peelability of the copper foil ZB containing the support film is significantly improved. It can be completely peeled off from the surface of the cathode roller 11 by the guide roller 23, and then passivated (optionally) and wound up, which reduces the loss of copper foil 10, improves production efficiency and further reduces production costs.

[0186] Further, see Figure 9 By changing the position of the composite copper foil conveying roller assembly 3, the transport path of the electrolytic copper foil ZB containing the support film can be altered. This allows the existing foil-making equipment to be used simultaneously as the foil-making device 1, passivation device 4, and winding device 5 in the production system for preparing electrolytic copper foil containing the support film, without requiring modifications to the existing foil-making equipment 1. This significantly improves the utilization rate of the existing foil-making equipment 1 and greatly reduces equipment costs. Furthermore, the film conveying roller 3 is located around the support film unwinding device 100. The electrolytic copper foil ZB containing the support film forms a U-shaped transport path around the support film unwinding device 100 on the film conveying roller 3, with the U-shaped opening facing the copper foil winding device 15, which can act as the winding device 5 to wind the electrolytic copper foil ZB containing the support film. Understandably, before winding, the electrolytic copper foil ZB containing the support film can also be transported to the copper foil passivation device 14 as needed, which can act as the passivation device 4 to passivate the electrolytic copper foil ZB containing the support film. For example, see Figure 9 The membrane material transport roller 3 includes a membrane material transport first roller 31, located above the guide roller 23. This is a turning roller used to turn the electrolytic copper foil ZB containing the support film. Specifically, after being peeled off by the guide roller 23, the copper foil 10 of the electrolytic copper foil ZB containing the support film faces the cathode roller 11. After being turned by the membrane material transport first roller 31, the support film 20 in the electrolytic copper foil ZB containing the support film faces the cathode roller 11, while the copper foil 10 faces away from the cathode roller 11. The membrane material transport roller 3 also includes a membrane material transport second roller 32, located downstream of the membrane material transport first roller 31, around the periphery of the support film unwinding device 100. This roller is used for better flattening and controlling the tension of the composite copper foil during transport. See also... Figure 9 The support film 20 is transported in the following order: support film unwinding device 100, guide roller 21, composite pressure roller 22, guide roller 23, film material transport first pass roller 31, film material transport second pass roller 32, copper foil passivation device 14 and copper foil winding device 15.

[0187] For ease of description, the production system for preparing the first electrolytic copper foil with a support film will be referred to as ZBS-1 below. Correspondingly, the cathode roller 11 used is the first cathode roller 111, the electrolytic cell 12 is the first electrolytic cell 121, and the first support film composite device 2 includes the first guide roller 211, the first composite pressure roller 221 and the first guide roller 231. Similarly, the production system for the first electrolytic copper foil with a support film, referred to as ZBS-1, also includes the first passivation device 4-1 and the first winding device 5-1. The production system for preparing the second electrolytic copper foil containing the support film is designated as ZBS-2. Correspondingly, the cathode roller 11 used is the second cathode roller 112, the electrolytic cell 12 is the second electrolytic cell 122, and the second support film composite device 2-2 includes a second guide roller 212, a second composite pressure roller 222, and a second guide roller 232. Similarly, the production system for the second electrolytic copper foil containing the support film designated as ZBS-2 also includes a second passivation device 4-2 and a second winding device 5-2.

[0188] See Figure 11 This application also provides a method for implementation Figure 1 The composite copper foil production system of the method for preparing composite copper foil shown includes:

[0189] The first electrolytic copper foil production system ZBS-1 with a supporting film includes:

[0190] The first support film unwinding device 100-1 is used to unwind the support film 20-1;

[0191] The first foil-generating device 1-1 includes a first electrolytic cell 121 and a first cathode roller 111, used to generate a first copper foil 10-1;

[0192] The first support film composite device 2-1 includes a first guide roller 211, a first composite pressure roller 221 and a first guide roller 231, which is used to composite the first support film 20-1 and the first copper foil 10-1 to obtain and peel off the first electrolytic copper foil ZB-1 containing the support film.

[0193] The first adhesive coating system 2000 is located downstream of the first electrolytic copper foil production system ZBS-1 containing a support film. It includes a first adhesive coating device 2001 for coating the first copper foil 10-1 with adhesive to prepare a first adhesive layer 30-1; and a first heating device 2002 for performing a first heating treatment on the first adhesive layer 30-1 to improve the adhesiveness and thus improve the composite effect.

[0194] Base film unwinding system 3000, used for unwinding polymer base film 40;

[0195] The first composite system 4000 is located downstream of the first adhesive coating system 2000 and the base film unwinding system 3000, and includes a first composite roller group 4001 for bonding the first electrolytic copper foil containing the support film and the first adhesive layer 30-1 to the first side surface of the polymer base film 40.

[0196] The first support film peeling and winding device 501 is located downstream of the first composite system 4000 and includes a first support film peeling roller 5011 for peeling the first support film 20-1 and conveying the single-sided composite copper foil downstream; and a first support film winding roller 5012 for winding the first support film 20-1 after being peeled from the first support film peeling roller 5011.

[0197] The composite copper foil winding system 6000 is located downstream of the first support film peeling and winding device 501 and is used to wind up the composite copper foil.

[0198] The first electrolytic copper foil production system ZBS-1 containing the support film, the first adhesive coating system 2000, and the first support film peeling and winding device 501 are all located on the first side of the polymer base film 40.

[0199] See Figure 11 The polymer base film 40 is transported in the following order: base film unwinding system 3000, first composite system 4000, first support film peeling roller 5011, and composite copper foil winding system 6000.

[0200] Understandably, see Figure 11 To improve the oxidation resistance of the composite copper foil, a composite copper foil passivation system 7000 can be installed downstream of the first support film peeling and winding device 501 and upstream of the composite copper foil winding system 6000 to passivate the single-sided composite copper foil intermediate. The specific setup can refer to conventional passivation systems in the art, and this application does not impose any special limitations on it. Additionally, it is understood that, in order to better flatten and control the tension of the polymer base film 40, the electrolytic copper foil ZB containing the support film, or the composite copper foil intermediate during the transport process, some transport rollers (or tension rollers) 1001 can be arranged on the composite copper foil production system as needed (some transport rollers are not marked in the attached figures). Furthermore, to avoid excessive overlap of film materials, the attached... Figures 11-19 The composite copper foil production system in the article omits the adhesive layer 30.

[0201] As mentioned above, this application, in addition to being able to prepare such... Figure 3 The single-sided composite copper foil DFB shown can also be used to prepare, for example... Figure 4The double-sided composite copper foil SFB is shown. In addition, it can be understood that the main difference between preparing double-sided composite copper foil SFB and preparing single-sided composite copper foil is that it is necessary to prepare electrolytic copper foil ZB containing a support film twice, which is composited with polymer base film 40 (double composite) and the support film 20 is peeled and wound up twice. The support film 20-1 and the second support film 20-2 can be peeled off separately or simultaneously.

[0202] See Figure 12 This application provides a method for implementing such Figure 6 The production system for the preparation method of the double-sided composite copper foil, the composite copper foil production system comprising:

[0203] As above Figure 11 The system shown comprises a first electrolytic copper foil production system ZBS-1 with a support film, a base film unwinding system 3000, a first composite system 4000, a first support film peeling and winding device 501, a composite copper foil passivation system 7000, and a composite copper foil winding system 6000; and

[0204] The second electrolytic copper foil production system ZBS-2, which includes a supporting film, comprises:

[0205] The second support film unwinding device 100-2 is used to unwind the support film 20-2;

[0206] The second foil-generating device 1-2 includes a second electrolytic cell 122 and a second cathode roller 112, used to generate a second copper foil 10-2;

[0207] The second support film composite device 2-2 includes a second guide roller 212, a second composite pressure roller 222 and a second guide roller 232, for composite the second support film 20-2 and the second copper foil 10-2 to obtain and peel off the second electrolytic copper foil ZB-2 containing the support film.

[0208] The second adhesive coating system 9000 is located downstream of the second electrolytic copper foil production system ZBS-2 containing a support film. It includes a second adhesive coating device 9001 for coating the second copper foil 10-2 with adhesive to prepare a second adhesive layer 30-2; and a second heating device 2002 for performing a second heating treatment on the second adhesive layer 30-2 to improve the adhesiveness and thus improve the composite effect.

[0209] The second composite system 10000 is located downstream of the second coating system 9000 and the base film unwinding system 3000, and upstream of the first composite system 4000. It includes a second composite roller group 10001 for composite polymer base film 40, second adhesive layer 30-2 and second electrolytic copper foil ZB-2 containing a support film.

[0210] The second support film peeling and winding device 502 is located downstream of the second composite system 10000 and upstream of the composite copper foil passivation system 7000 and the composite copper foil winding system 6000. It includes a second support film peeling roller 5021 for peeling the second support film 20-2 and conveying the composite copper foil intermediate to the downstream; and a second support film winding roller 5022 for winding the second support film 20-2 after being peeled from the second support film peeling roller 5021.

[0211] The first electrolytic copper foil production system ZBS-1 with a support film, the first adhesive coating system 2000, and the first support film peeling and winding device 501 are all located on the first side of the polymer base film 40; the second electrolytic copper foil production system ZBS-2 with a support film, the second adhesive coating system 9000, and the second support film peeling and winding device 502 are all located on the second side of the polymer base film 40.

[0212] Understandably, the first support membrane 20-1 and the second support membrane 20-2 can be peeled off stepwise or simultaneously. For the simultaneous peeling scheme, see [link to relevant documentation]. Figure 12 The second support film peeling and winding device 502 and the first support film peeling and winding device 501 are both located downstream of the first composite system 4000. The second support film peeling roller 5021 and the first support film peeling roller 5011 are the same. They simultaneously peel off the second support film 20-2 and the first support film 20-1 through reverse peeling action and transfer the composite copper foil intermediate to the downstream. The peeled second support film 20-2 is wound up by the second support film winding roller 5022, and the peeled first support film 20-1 is wound up by the first support film winding roller 5012.

[0213] Additionally, as described above, this application can choose to first wind up the electrolytic copper foil ZB containing the support film, and then perform the unwinding and lamination operations. This helps reduce the difficulty of equipment layout and makes it easier to control the production line speed of each functional area, thereby reducing subsequent shrinkage or empty lamination of the composite copper foil. For example, it can be done according to... Figure 7 or Figure 9 The production system shown for preparing electrolytic copper foil ZB with a support film ZBS prepares and winds the electrolytic copper foil ZB with the support film, and then unwinds it to the composite copper foil production line for preparing composite copper foil.

[0214] See Figure 13 This application provides another composite copper foil production system (in this embodiment, the electrolytic copper foil ZB containing the support film is first wound up, then unwound and transported downstream to be laminated with the polymer base film 40), the composite copper foil production system includes:

[0215] The first unwinding system 1000 is used to unwind the first electrolytic copper foil ZB-1 containing the support film;

[0216] The first adhesive coating system 2000 is located downstream of the first unwinding system 1000 and includes a first adhesive coating device 2001 for coating the first copper foil 10-1 with adhesive to prepare a first adhesive layer 30-1; and a first heating device 2002 for performing a first heating treatment on the first adhesive layer 30-1 to improve adhesiveness and thus improve the composite effect.

[0217] like Figure 11 The base film unwinding system 3000, the first composite system 4000, the first support film peeling and winding device 501, the composite copper foil passivation system 7000, and the composite copper foil winding system 6000 are shown.

[0218] The first unwinding system 1000, the first adhesive coating system 2000, and the first support film peeling and winding device 501 are all located on the first side of the polymer base film 40.

[0219] See Figure 13 The polymer base film 40 is transported in the following order: base film unwinding system 3000, first composite system 4000, first support film peeling roller 5011, composite copper foil passivation system 7000 and composite copper foil winding system 6000.

[0220] Understandably, such as Figure 13 The composite copper foil production system shown can produce, in addition to, the following: Figure 3 The single-sided composite copper foil DFB shown can also be used to prepare, for example... Figure 4 The double-sided composite copper foil SFB is shown. The main difference between preparing a double-sided composite copper foil SFB and a single-sided composite copper foil is that it requires two winding and unwinding operations of the electrolytic copper foil ZB containing the support film, respectively with the polymer base film 40 (double-layer composite) and two peeling and winding operations of the support film 20. Optionally, the base film unwinding system 1000 first unwinds the polymer base film 40, then unwinds the single-sided composite copper foil, and the support film 20-1 and the second support film 20-2 can be peeled off separately (see...). Figure 14 ) or simultaneous stripping (see Figure 15 ).

[0221] See Figure 16 This application provides a double-sided composite copper foil production system. In this embodiment, both the first electrolytic copper foil ZB-1 containing a support film and the second electrolytic copper foil ZB-2 containing a support film undergo winding and unwinding. The first support film 20-1 and the second support film 20-2 are simultaneously peeled off. The composite copper foil production system includes:

[0222] The second unwinding system 8000 is used to unwind the second electrolytic copper foil ZB-2 containing a support film;

[0223] The second adhesive coating system 9000 is located downstream of the second unwinding system 8000 and includes a second adhesive coating device 9001 for coating the second copper foil 10-2 with adhesive to prepare the second adhesive layer 30-2; and a second heating device 9002 for performing a second heating treatment on the second adhesive layer 30-2 to improve the adhesiveness and thus improve the composite effect.

[0224] Base film unwinding system 3000, used for unwinding polymer base film 40;

[0225] The second composite system 10000 is located downstream of the second adhesive coating system 9000 and the base film unwinding system 3000, and includes a second composite roller group 10001 for composite polymer base film 40, second adhesive layer 30-2 and second electrolytic copper foil ZB-2 containing a support film.

[0226] The first unwinding system 1000 is used to unwind the first electrolytic copper foil ZB-1 containing the support film;

[0227] The first adhesive coating system 2000 is located downstream of the first unwinding system 1000 and includes a first adhesive coating device 2001 for coating the first copper foil 10-1 with adhesive to prepare a first adhesive layer 30-1; and a first heating device 2002 for performing a first heating treatment on the first adhesive layer 30-1 to improve adhesiveness and thus improve the composite effect.

[0228] The first composite system 4000 is located downstream of the first adhesive coating system 2000 and the second composite system 10000, and includes a first composite roller group 4001 for bonding the first electrolytic copper foil containing the support film and the first adhesive layer 30-1 to the first side surface of the polymer base film 40.

[0229] The first support film peeling and winding device 501 and the second support film peeling and winding device 502 are both located downstream of the first composite system 4000. The first support film peeling roller 5011 and the second support film peeling roller 5021 are the same. They simultaneously peel off the first support film 20-1 and the second support film 20-2 through reverse peeling action and transfer the composite copper foil intermediate to the downstream. The peeled first support film 20-1 is wound up by the first support film winding roller 5012, and the peeled second support film 20-2 is wound up by the second support film winding roller 5022.

[0230] The composite copper foil passivation system 7000 is located downstream of the first support film peeling and winding device 501 and the second support film peeling and winding device 502, and is used to passivate the composite copper foil intermediate.

[0231] The composite copper foil winding system 6000 is located downstream of the composite copper foil passivation system 7000 and is used to wind up the composite copper foil.

[0232] The first unwinding system 1000, the first coating system 2000, and the first support film take-up roller 5012 are all located on the first side of the polymer base film 40; the second unwinding system 8000, the second coating system 9000, and the second support film take-up roller 5022 are all located on the second side of the polymer base film 40.

[0233] See Figure 16 The polymer base film 40 is transported in the following order: base film unwinding system 3000, second composite system 10000, first composite system 4000, first support film peeling roller 5011 / second support film peeling roller 5021, composite copper foil passivation system 7000 and composite copper foil winding system 6000.

[0234] See Figure 17 In order to coordinate the linear speed and tension of each membrane material in the first composite system and the second composite system, and to ensure the continuous and stable operation of each production line, a buffer loop 11000 can be set between the first composite system 4000 and the second composite system 10000.

[0235] See Figure 18 This application also provides another double-sided composite copper foil production system. In this embodiment, both the first electrolytic copper foil ZB-1 containing a support film and the second electrolytic copper foil ZB-2 containing a support film undergo winding and unwinding. The first support film 20-1 and the second support film 20-2 are simultaneously peeled off. The composite copper foil production system includes:

[0236] The second unwinding system 8000 is used to unwind the second electrolytic copper foil ZB-2 containing a support film;

[0237] The second adhesive coating system 9000 is located downstream of the second unwinding system 8000 and includes a second adhesive coating device 9001 for coating the second copper foil 10-2 with adhesive to prepare a second adhesive layer 30-2; and a second heating device 9002 for performing a second heating treatment on the second adhesive layer 30-2 to improve adhesiveness and thus improve the composite effect.

[0238] Base film unwinding system 3000, used for unwinding polymer base film 40;

[0239] The second composite system 10000 is located downstream of the second adhesive coating system 9000 and the base film unwinding system 3000, and includes a second composite roller group 10001 for composite polymer base film 40, second adhesive layer 30-2 and second electrolytic copper foil ZB-2 containing a support film.

[0240] The first unwinding system 1000 is used to unwind the first electrolytic copper foil ZB-1 containing the support film;

[0241] The first adhesive coating system 2000 is located downstream of the first unwinding system 1000 and includes a first adhesive coating device 2001 for coating the first copper foil 10-1 with adhesive to prepare a first adhesive layer 30-1; and a first heating device 2002 for performing a first heating treatment on the first adhesive layer 30-1 to improve adhesiveness and thus improve the composite effect.

[0242] The first composite system 4000 is located downstream of the first adhesive coating system 2000 and the second composite system 10000, and includes a first composite roller group 4001 for bonding the first electrolytic copper foil containing the support film and the first adhesive layer 30-1 to the first side surface of the polymer base film 40.

[0243] The first support film peeling and winding device 501 and the second support film peeling and winding device 502 are both located downstream of the first composite system 4000. The first support film peeling roller 5011 and the second support film peeling roller 5021 are the same. They simultaneously peel off the first support film 20-1 and the second support film 20-2 through reverse peeling action and transfer the composite copper foil intermediate to the downstream. The peeled first support film 20-1 is wound up by the first support film winding roller 5012, and the peeled second support film 20-2 is wound up by the second support film winding roller 5022.

[0244] The composite copper foil passivation system 7000 is located downstream of the first support film peeling and winding device 501 and the second support film peeling and winding device 502, and is used to passivate the composite copper foil intermediate.

[0245] The composite copper foil winding system 6000 is located downstream of the composite copper foil passivation system 7000 and is used to wind up the composite copper foil.

[0246] In this embodiment, the first unwinding system 1000, the first coating system 2000, and the first support film winding roller 5012 are all located on the first side of the polymer base film 40; and the second heating device 9002 and the first heating device 2002 are located in the same heating system 2003. This embodiment adopts a three-dimensional integrated layout, making full use of vertical space and vertically integrating process equipment, thereby optimizing the space of the production line. While ensuring the process flow remains unchanged, it shortens the floor area of ​​the equipment / production line, effectively reduces the need for lateral space, and significantly reduces equipment costs. Further, see... Figure 18 The second heating device 9002 and the first heating device 2002 are symmetrically arranged, such as axially symmetrical arrangement, with the first copper foil 10-1 facing the second copper foil 10-2.

[0247] See Figure 18The polymer base film 40 is transported in the following order: base film unwinding system 3000, second composite system 10000, first composite system 4000, first support film peeling roller 5011 / second support film peeling roller 5021, composite copper foil passivation system 7000 and composite copper foil winding system 6000.

[0248] Additionally, see Figure 19 In order to coordinate the linear speed and tension of each membrane material in the first composite system and the second composite system, and to ensure the continuous and stable operation of each production line, a buffer loop 11000 can be set between the first composite system 4000 and the second composite system 10000.

[0249] This application also provides a battery comprising a current collector, said current collector being prepared according to the method for preparing composite copper foil as described above. Given that composite copper foil has advantages such as being thin and light, possessing excellent mechanical properties, and having good processability, batteries made from current collectors prepared using this composite copper foil have advantages such as high energy density, good cycle performance, and safety and reliability.

[0250] This application also provides an electrical device comprising a battery as described above, the battery providing electrical energy to the electrical device. Exemplarily, the electrical device includes products such as vehicles, lighting equipment, industrial robotic arms or robots, medical devices, and consumer electronics (such as handheld appliances, wearable electronics, and smart home devices). Exemplarily, the electrical device includes, but is not limited to: automobiles, electric bicycles, lighting equipment, robotic arms, robots, medical devices, cooling / heating equipment, AR / VR / MR headsets, smart audio glasses, Bluetooth headsets, wearable speakers, smartwatches, smart bracelets, smart rings, SIM cards, bank cards, smart cards, information cards, heated clothing, smart shoes, smart belts, portable sensors, smart tags, smart locks, cameras, remote controls, mobile phones, computers, or tracking devices.

[0251] The technical solution of this application will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0252] 1. Raw material description:

[0253] (1) The description of the support membrane is shown in Table 1 below:

[0254] Table 1

[0255]

[0256] (2) The first adhesive layer 30-1 and the second adhesive layer 30-2 have the same composition, both being polyurethane adhesives. The first and second heat treatment processes are both gradient heating followed by gradient cooling. Specifically, the temperature is gradually increased from room temperature to 50°C, then gradually increased to 60°C, 70°C and 80°C, and then gradually decreased to 70°C, 60°C and 50°C. The thickness of a single layer is about 0.75 μm. The bonding force between the first adhesive layer 30-1 and the first copper foil 10-1 is 2.0 N / 25 mm to 2.1 N / 25 mm, and the bonding force between the second adhesive layer 30-2 and the second copper foil 10-2 is 2.0 N / 25 mm to 2.1 N / 25 mm.

[0257] (3) PET base film: commercially available, with a thickness of approximately 4.5 μm.

[0258] (4) Copper foil: self-made, preparation method is as follows:

[0259] S100. Prepare the electrolyte according to the formula in Table 2, and supply the electrolyte between the anode plate and the cathode roller;

[0260] S200, under the conditions of electrolyte temperature of 45℃~55℃ and anode current density of 50A / dm²~60A / dm², the electrolyte is circulated to electrolyze and produce foil, and an ultrathin copper foil with a thickness of about 1μm is obtained. It is understood that the thickness refers to the average thickness, and due to the limitations of the measurement method, there may be errors within the acceptable range in this field.

[0261] Table 2 Electrolyte Formulation

[0262]

[0263] HEC stands for hydroxyethyl cellulose, specifically a mixture of hydroxyethyl cellulose with viscosities of 24000 mPa·s and 30000 mPa·s in a weight ratio of 1:1; SPS stands for sodium polydisulfide dipropane sulfonate; and PEG stands for polyethylene glycol.

[0264] (5) Passivation solution: The passivation solutions in the following examples have the same composition, including water, citric acid 1g / L, benzotriazole 0.5g / L and methylbenzotriazole 0.1g / L.

[0265] In addition, it is understood that the thickness described in this application refers to the average thickness, which is subject to error within the acceptable range in the art due to limitations in the measurement method.

[0266] 2. The testing method is as follows:

[0267] (1) The mechanical properties test methods for electrolytic copper foil ZB with supporting film and composite copper foil FB are based on GB / T29847-2013, and the test instrument is Dongguan Sitai ST-D200.

[0268] (2) Peelability of ultra-thin copper foil: Peel the electrolytic copper foil ZB containing the support film from the cathode roller 11 and observe whether there is copper foil 10 residue on the cathode roller 11. If there is no residue, it indicates that the copper foil peelability is good. If there is residue, it indicates that the copper foil peelability is poor.

[0269] (3) Peelability of the support film: Peel the first support film 20-1 and the second support film 20-2 from the double-sided composite copper foil intermediate and observe whether there is any support film residue on the double-sided composite copper foil intermediate and whether the copper foil is damaged. If there is no support film residue and / or the copper foil is intact, it indicates that the support film has good peelability. If there is support film residue and / or the copper foil is damaged, it indicates that the support film has poor peelability.

[0270] (3) Antioxidant properties of electrolytic copper foil ZB with support film and composite copper foil FB: Place the electrolytic copper foil or composite copper foil with support film in a constant temperature oven at 140℃±2℃ for 15min and observe the appearance of the copper foil.

[0271] Example 1

[0272] This embodiment provides an electrolytic copper foil ZB with a supporting film and its preparation method, and a double-sided composite copper foil SFB and its preparation method, as detailed below:

[0273] (1) Adopt Figure 7 The production system shown prepares electrolytic copper foil ZB containing a support film:

[0274] The support film unwinding system 100 unwinds the support film 20, wherein the support film is a PE electrostatic film-1;

[0275] An ultrathin copper foil 10 with a thickness of approximately 1 μm is generated on the surface of a cathode roller 11 using an electrolytic method and existing foil-making equipment 1.

[0276] The support film 20 is laminated onto the surface of the copper foil 10 by a roll forming process in the support film laminating device 2 to prepare an electrolytic copper foil ZB containing a support film.

[0277] The electrolytic copper foil ZB containing the support film is peeled off from the surface of the cathode roller 11, and no ultra-thin copper foil residue remains on the surface of the cathode roller 11.

[0278] The electrolytic copper foil ZB containing the supporting film is conveyed to the copper foil passivation device 14 through the film conveying rollers 31 and 32 for passivation treatment.

[0279] The passivated electrolytic copper foil ZB containing the support film is wound up using a copper foil winding device 15.

[0280] (2) Adopt Figure 17 The composite copper foil production system shown prepares double-sided composite copper foil (SFB):

[0281] The electrolytic copper foil ZB containing the support film obtained by the second unwinding system 8000 unwinding (1) is marked as the second electrolytic copper foil ZB-2 containing the support film.

[0282] The second coating system 9000 coats and heats the second electrolytic copper foil ZB-2 containing the support film to prepare the second adhesive layer 30-2, and then transfers it to the downstream second composite system 10000.

[0283] The base film unwinding system 3000 unwinds the PET base film to the downstream second composite system 10000;

[0284] The second composite system 10000 composites the second electrolytic copper foil ZB-2 containing the support film onto the second side surface of the polymer base film 40 through the action of roll forming and the second adhesive layer 30-2, and then transfers it to the downstream buffer loop 11000 and the first composite system 4000.

[0285] The electrolytic copper foil ZB containing the support film obtained by the first unwinding system 1000 unwinding (1) is marked as the first electrolytic copper foil ZB-1 containing the support film.

[0286] The first coating system 4000 coats and heats the first electrolytic copper foil ZB-1 containing a support film to prepare the first adhesive layer 30-1, and then transfers it to the downstream first composite system 4000.

[0287] The first composite system 4000 composites the first electrolytic copper foil ZB-1 containing the support film onto the first side surface of the polymer base film 40 through the action of roll forming and the first adhesive layer 30-1, and then transfers it to the downstream first support film peeling and winding device 501 and the second support film peeling and winding device 502.

[0288] A double-sided composite copper foil intermediate is prepared by peeling and winding the first support film 20-1 and the second support film 20-2 using the first support film peeling and winding device 501 and the second support film peeling and winding device 502 respectively. The appearance of the first copper foil 10-1 and the second copper foil 10-2 after peeling off the support film 20 is observed.

[0289] The double-sided composite copper foil intermediate is transferred to the composite copper foil passivation system 7000 for passivation treatment, and then wound up in the composite copper foil winding system 6000 to prepare the double-sided composite copper foil SFB. See product image. Figure 20 The copper foil surface is flat, without wrinkles, warping, or residual adhesive.

[0290] Example 2

[0291] This embodiment provides an electrolytic copper foil containing a support film and its preparation method, as well as a double-sided composite copper foil and its preparation method. The difference between this embodiment and Embodiment 1 is that the support film is a PVC electrostatic film-2.

[0292] Example 3

[0293] This embodiment provides an electrolytic copper foil containing a support film and its preparation method, as well as a double-sided composite copper foil and its preparation method. The difference between this embodiment and Embodiment 1 is that the support film is a PVC electrostatic film-3.

[0294] Example 4

[0295] This embodiment provides an electrolytic copper foil with a supporting film and its preparation method, as well as a double-sided composite copper foil and its preparation method. The difference between this embodiment and Embodiment 1 is that the thickness of the copper foil is approximately 2 μm.

[0296] Example 5

[0297] This embodiment provides an electrolytic copper foil with a supporting film and its preparation method, and a double-sided composite copper foil and its preparation method. The difference between this embodiment and Embodiment 1 is that the supporting film is a PET adhesive film.

[0298] Example 6

[0299] This embodiment provides an electrolytic copper foil containing a support film and its preparation method, as well as a double-sided composite copper foil and its preparation method. The difference between this embodiment and Embodiment 1 is that the support film is a PP adhesive film.

[0300] Example 7

[0301] This embodiment provides an electrolytic copper foil with a supporting film and its preparation method, as well as a double-sided composite copper foil and its preparation method. The difference between this embodiment and Embodiment 4 is that the supporting film is a PP adhesive film.

[0302] Comparative Example 1

[0303] This comparative example provides an electrolytic copper foil and its preparation method. The difference between this example and Example 1 is that the step of unwinding the support film and then combining the support film with the copper foil is omitted. The ultra-thin copper foil with a thickness of about 1 μm is directly peeled off from the surface of the cathode roller, and the peeling fails.

[0304] Comparative Example 2

[0305] This comparative example provides an electrolytic copper foil and its preparation method. The difference between this example and Example 4 is that the step of unwinding the support film and then combining the support film with the copper foil is omitted. The ultra-thin copper foil with a thickness of about 1 μm is directly peeled off from the surface of the cathode roller, and the peeling fails.

[0306] test

[0307] I. The electrolytic copper foils containing the supporting film in Examples 1 to 7 were tested, and the results are shown in Table 3 below.

[0308] Table 3

[0309] As shown in Table 3, this application uses an online composite method of support film and electrolytic copper foil to directly prepare electrolytic copper foil containing support film on the surface of cathode roller. The support film includes electrostatic film and / or adhesive film, which can significantly improve the peelability of ultra-thin copper foil. The electrolytic copper foil containing support film can be peeled off from the surface of cathode roller as a whole, which can effectively avoid defects such as copper foil tearing and breakage.

[0310] II. The composite copper foils in Examples 1 to 7 were tested, and the results are shown in Table 4 below.

[0311] Table 4. Parameters and performance results of double-sided composite copper foil (SFB)

[0312] As shown in Table 4, this application prepares an adhesive layer by coating the copper foil surface with adhesive. Utilizing the adhesive properties of the adhesive layer, a polymer base film can be directly and stably bonded to the surface of an electrolytic copper foil containing a support film to form a composite copper foil. This results in high composite strength and structural stability between the polymer base film and the copper foil. The support film is then peeled off after bonding. The operation is simple, quick, and easy to control. There is no adhesive residue on the copper foil surface. The resulting composite copper foil has good mechanical properties and appearance, good oxidation resistance, and excellent overall performance, showing broad application prospects.

[0313] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0314] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing composite copper foil, characterized in that, Includes the following steps: S100: Copper foil is generated on the surface of the cathode roller by electrolysis; S200: A support film is laminated onto the surface of the copper foil by a roll forming process to prepare a first electrolytic copper foil containing a support film, wherein the support film is one or more of an electrostatic film and an adhesive film. S300: Peel the first electrolytic copper foil containing the support film from the surface of the cathode roller; S400: Take the first electrolytic copper foil containing the support film, which includes a first copper foil and a first support film stacked in sequence, and apply adhesive to the surface of the first copper foil to prepare a first adhesive layer; S500: Through the action of the first adhesive layer, the first electrolytic copper foil containing the support film is laminated onto the first side surface of the polymer base film; S600: Peel off the first support membrane; Wherein, the bonding force between the first support film and the first copper foil is F1, and the bonding force between the first adhesive layer and the first copper foil is F2, and F1 and F2 satisfy: F1 < F2.

2. The method for preparing composite copper foil according to claim 1, characterized in that, Satisfy one or more of the following conditions (1) to (3): (1) F1 and F2 satisfy: F2 / F1≥1.5; (2) The tensile strength of the support membrane is ≥150 MPa, the elongation at break is ≥80%, and the tensile strength corresponding to a constant elongation of 3% is ≥40 MPa. (3) The thickness of the support film is 15μm~50μm.

3. The method for preparing composite copper foil according to claim 2, characterized in that, Satisfy one or more of the following (1)~(2): (1) F1 is 0.5N / 25mm~1.0N / 25mm; (2) F2 is 1.5N / 25mm~5.0N / 25mm.

4. The method for preparing composite copper foil according to claim 1, characterized in that, Satisfy one or more of the following (1)~(2): (1) The material of the electrostatic film is one or more of polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride, polybutylene terephthalate, polyurethane and ethylene-vinyl acetate copolymer; (2) The adhesive film includes a substrate and an adhesive layer on the surface of the substrate, wherein the substrate is made of one or more of the following materials: polyethylene terephthalate, polyethylene, polypropylene, polyimide, polyamide, polyester, polyvinyl chloride, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride, polybutylene terephthalate, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene terpolymer, polysulfone, polyethylene naphthalate, poly3,4-ethylenedioxythiophene, polyaniline, and polypyrrole; and the adhesive layer includes one or more of the following materials: rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, organosilicon polymers and their modified compounds, and polyolefins and their modified compounds.

5. The method for preparing composite copper foil according to any one of claims 1 to 4, characterized in that, Satisfy one or more of the following conditions (1) to (8): (1) The thickness of the copper foil is 0.8μm~6μm; (2) The thickness of the polymer base film is 1μm~6μm; (3) The polymer base film is made of one or more of the following materials: polyethylene terephthalate, polyethylene, polypropylene, polyimide, polyamide, polyester, polyvinyl chloride, polystyrene, polytetrafluoroethylene, polyvinylidene fluoride, polybutylene terephthalate, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene terpolymer, polysulfone, polyethylene naphthalate, poly3,4-ethylenedioxythiophene, polyaniline and polypyrrole; (4) The thickness of the first adhesive layer is 0.2 μm to 4 μm; (5) The first adhesive layer comprises one or more of the following: rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, organosilicon polymer and its modified compounds, and polyolefin and its modified compounds. (6) After step S300 and before step S400, the method further includes a passivation treatment and / or a winding treatment of the electrolytic copper foil containing the support film; (7) S400 further includes the step of performing a first heat treatment on the first adhesive layer; (8) After step S600, the composite copper foil is further subjected to passivation treatment and / or winding treatment.

6. The method for preparing composite copper foil according to claim 5, characterized in that, It also includes the following steps: A100: Repeat steps S100, S200 and S300 to prepare the second electrolytic copper foil containing the support film, which includes a second copper foil and a second support film stacked in sequence; A200: Apply adhesive to the surface of the second copper foil to prepare a second adhesive layer; A300: The second electrolytic copper foil containing the support film is laminated to the second side surface of the polymer base film through the action of the second adhesive layer; A400: Peel off the second support membrane; Wherein, the bonding force between the second support film and the second copper foil is F3, and the bonding force between the second adhesive layer and the second copper foil is F4, and F3 and F4 satisfy: F3 < F4.

7. The method for preparing composite copper foil according to claim 6, characterized in that, F3 and F4 satisfy the condition: F4 / F3≥1.

5.

8. The method for preparing composite copper foil according to claim 7, characterized in that, Satisfy one or more of the following (1)~(2): (1) F3 is 0.5N / 25mm~1.0N / 25mm; (2) F4 is 1.5N / 25mm~5.0N / 25mm.

9. The method for preparing composite copper foil according to claim 6, characterized in that, Satisfy one or more of the following conditions (1) to (4): (1) The thickness of the second adhesive layer is 0.2 μm to 4 μm; (2) The second adhesive layer comprises one or more of the following: rosin resin, terpene resin, petroleum resin, polyurethane resin, polyacrylic resin, epoxy resin, phenolic resin, polyester resin, polyimide, organosilicon polymer and its modified compounds, and polyolefin and its modified compounds. (3) A200 further includes a step of performing a second heat treatment on the second adhesive layer; (4) After step A400, the composite copper foil after the second support film is stripped is further subjected to passivation treatment.

10. A composite copper foil production system for implementing the method for preparing composite copper foil according to any one of claims 1 to 9, characterized in that, include: A first electrolytic copper foil production system containing a support film includes: a first support film unwinding device for unwinding a first support film; a first foil production device including a first cathode roller for at least producing a first copper foil; and a first support film laminating device including a first laminating roller group that abuts against the first cathode roller for laminating the first support film and the first copper foil to obtain a first electrolytic copper foil containing a support film. The first adhesive coating system is located downstream of the first electrolytic copper foil production system containing a support film, and includes a first adhesive coating device for coating the first copper foil with adhesive to prepare a first adhesive layer. A base film unwinding system, used at least for unwinding polymer base films; The first composite system, located downstream of the first coating system and the base film unwinding system, includes a first composite roller group for bonding a first electrolytic copper foil containing a support film and a first adhesive layer to a first side surface of the polymer base film. A first support film peeling and winding device is located downstream of the first composite system and is used to peel and wind up the first support film. Composite copper foil winding system for winding composite copper foil; The polymer base film is transported at least in the path sequence of the base film unwinding system, the first composite system, and the composite copper foil winding system.

11. The composite copper foil production system according to claim 10, characterized in that, Also includes: A second electrolytic copper foil production system containing a support film includes: a second support film unwinding device for unwinding a second support film; a second foil production device including a second cathode roller for at least producing a second copper foil; and a second support film laminating device including a second laminating roller group that abuts against the second cathode roller for laminating the second support film and the second copper foil to obtain a second electrolytic copper foil containing a support film. The second coating system, located downstream of the second electrolytic copper foil production system containing the support film, includes a second coating device for coating the second copper foil with adhesive to prepare a second adhesive layer. The second composite system is located downstream of the second coating system and the base film unwinding system and upstream of the first composite system. It includes a second composite roller group for bonding the second electrolytic copper foil containing the support film and the second adhesive layer to the second side surface of the polymer base film. The second support film peeling and winding device is located downstream of the second composite system and upstream of the composite copper foil winding system, and is used to peel and wind the second support film. The polymer base film is transported in at least the following path sequence: base film unwinding system, second composite system, first composite system, and composite copper foil winding system.

12. The composite copper foil production system according to claim 11, characterized in that, One or more of the following conditions (1) to (3) are met: (1) The second electrolytic copper foil production system containing a support film further includes a second winding device, which is located downstream of the second support film composite system and is used to wind up the second electrolytic copper foil containing a support film; the composite copper foil production system further includes a second unwinding system, which is located upstream of the second coating system and is used to unwind the second electrolytic copper foil containing a support film. (2) The second adhesive coating system further includes a second heating device, located downstream of the second adhesive coating device and upstream of the second composite system, for performing a second heating treatment on the second adhesive layer; (3) A buffer loop is provided between the first composite system and the second composite system to coordinate the linear speed and tension of each membrane material in the first composite system and the second composite system, so that each production line can operate continuously and stably. (4) The second support film peeling and winding device is located upstream of the first composite system; or, the first support film peeling and winding device and the second support film peeling and winding device are both located downstream of the first composite system.

13. The composite copper foil production system according to any one of claims 10 to 12, characterized in that, One or more of the following conditions (1) to (3) are met: (1) The first electrolytic copper foil production system containing a support film further includes a first winding device, which is located downstream of the first support film composite system and is used to wind up the first electrolytic copper foil containing a support film; the composite copper foil production system further includes a first unwinding system, which is located upstream of the first coating system and on the first side of the polymer base film and is used to unwind the first electrolytic copper foil containing a support film. (2) The first adhesive coating system further includes a first heating device, located downstream of the first adhesive coating device and upstream of the first composite system, for performing a first heating treatment on the first adhesive layer; (3) The composite copper foil production system also includes a composite copper foil passivation system, which is located upstream of the composite copper foil winding system and is used to passivate the composite copper foil.

14. The composite copper foil production system according to claim 13, characterized in that, The first electrolytic copper foil production system containing a support film, the first adhesive coating device, the first heating device, and the first support film peeling and winding device are all located on the first side of the base film unwinding system; the second electrolytic copper foil production system containing a support film, the second adhesive coating device, the second heating device, and the second support film peeling and winding device are all located on the second side of the base film unwinding system.

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