A method for producing a double-sided metallized polyaramid composite film, a polyaramid composite film

Abstract

This application relates to the technical field of battery materials, and in particular to a method for preparing a double-sided metallized polyaramid composite film, and the polyaramid composite film itself. The method for preparing a double-sided metallized polyaramid composite film includes the following steps: coating a polyaramid slurry onto at least one side of a base film to form a polyaramid coating on at least one side of the base film; performing double-sided metallization on the base film coated with the polyaramid coating to obtain a double-sided metallized polyaramid composite film; wherein the base film is a porous base film. This application discloses a method for preparing a double-sided metallized polyaramid composite film and the polyaramid composite film. Through the pore channels of the porous base film, metal particles can form a through-connection when the base film is double-sided metallized, achieving effective conductivity between the metal coatings on both sides, reducing the difficulty of subsequent battery welding, and simultaneously improving the interlayer bonding strength and high-temperature resistance of the coatings.

Description

Technical Field

[0001] This application relates to the technical field of battery materials, and in particular to a method for preparing a polyarylamide composite film with double-sided metal plating, and the polyarylamide composite film. Background Technology

[0002] With the rapid iteration of lithium-ion batteries and new energy storage devices towards higher power, higher safety, and miniaturization, current collectors, as the core load-bearing and conductive components of these devices, directly determine the electrochemical performance, cycle stability, and reliability of the equipment. Polyarylamides, due to their excellent mechanical strength, high-temperature resistance, chemical corrosion resistance, and lightweight properties, have made composite membranes from them the preferred current collector material in these fields, and are widely used in various new energy equipment such as power batteries and energy storage power stations.

[0003] Currently, the mainstream technical route for preparing polyarylamide composite current collector membranes in the industry usually uses non-porous polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET) films as substrate supports, and employs physical deposition processes such as magnetron sputtering to deposit conductive metal layers on both sides of the substrate film, thereby obtaining a polyarylamide composite membrane with conductive functions. Among these processes, magnetron sputtering has become the core technology for preparing the metal layer of existing composite membranes due to its advantages such as strong metal layer adhesion and controllable deposition rate.

[0004] However, existing preparation methods have many inherent defects, which seriously restrict the performance improvement and application promotion of polyarylamide composite films, specifically in the following aspects: First, the non-porous PE, PP, and PET substrate films used in existing solutions have a completely dense surface structure with no pores for material penetration. During the magnetron sputtering deposition of metal layers, high-energy metal particles can only physically adhere to the substrate surface and cannot penetrate into the substrate to form a through-connection. This results in the metal coatings on both sides of the substrate being independent and lacking effective conductive channels, leading to poor overall conductivity and high resistance of the composite film. This problem directly increases the welding difficulty in the subsequent battery assembly process, easily causing assembly defects such as poor welding contact, incomplete soldering, and desoldering. This not only affects the reliability of the internal connections of the battery but also significantly reduces the battery production yield and increases production costs.

[0005] Secondly, the bonding between the non-porous substrate and the metal coating is only a simple physical bond, and the adhesion between the two is weak. Meanwhile, the high-temperature resistance of substrate materials such as PE, PP, and PET is limited, and the magnetron sputtering process generates thermal radiation and ion bombardment heat, causing the substrate surface temperature to rise beyond its tolerance range, leading to problems such as substrate shrinkage, deformation, and even damage. These substrate abnormalities directly cause failure phenomena such as peeling and cracking of the surface metal coating, significantly reducing the mechanical strength, structural stability, and service life of the polyaramid composite film, failing to meet the requirements for long-term stable operation of new energy equipment.

[0006] In summary, existing polyarylamide composite membrane preparation technologies suffer from drawbacks such as poor conductivity, insufficient structural stability, and cumbersome preparation processes, which fail to meet the high-performance development needs of current lithium-ion batteries and new energy storage devices.

[0007] Therefore, developing a polyarylamide composite film preparation technology that can solve the above-mentioned technical pain points, simplify the preparation process, and improve product performance has become a key technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this application provides a method for preparing a polyaramid composite film with double-sided metal plating, and the polyaramid composite film itself.

[0009] In a first aspect, this application provides a method for preparing a double-sided metallized polyaramid composite film, employing the following technical solution: A method for preparing a double-sided metallized polyaramid composite film includes the following steps: A polyaramid slurry is coated on at least one side of a base film to form a polyaramid coating on at least one side of the base film; A base film coated with a polyaramid coating is subjected to double-sided metallization to obtain a double-sided metallized polyaramid composite film. The base membrane is a porous base membrane.

[0010] Preferably, the air permeability of the base membrane is 10-500 Sec / 100mL.

[0011] By adopting the above technical solution, this application selects a porous and breathable membrane as the base membrane. Through the pore structure of the base membrane, a through-conducting channel is constructed. When double-sided metal plating is performed on the base membrane, metal particles or ions can penetrate through the pores to the other side of the base membrane and form a cross-over or three-dimensional coating with the metal particles on the opposite side. This changes the independent series connection of the two coatings to parallel conduction, reducing the resistance of the composite membrane. At the same time, the pores enhance the bonding force between the coating and the base membrane through mechanical interlocking and buffer plasma thermal radiation to prevent the base membrane from deforming.

[0012] Preferably, the thickness of the polyaramid coating on one side is 0.1-3 μm.

[0013] By adopting the above technical solution, this application limits the single-sided thickness of the polyarylamide coating to 0.1-3μm, which takes into account both the conductivity of the coating and the thinness of the structure: if the thickness is too low, the conductive material cannot form a continuous conductive network, making it difficult to achieve stable conductivity and unable to support subsequent direct metal plating; if the thickness is too high, it will increase the overall thickness and weight of the composite film, which does not meet the development requirements of miniaturization and lightweighting of lithium-ion batteries and energy storage devices, and may also affect the adhesion between the coating and the base film, making the coating prone to peeling off.

[0014] Preferably, the base film includes at least one of PE, PP, and PET.

[0015] Preferably, the thickness of the base film is 2-20 μm.

[0016] By adopting the above technical solution, the thickness of the base film selected in this application is 2-20μm, which can balance the supporting strength of the base film and the overall thinness of the composite film: if the thickness is too low, the mechanical strength of the base film is insufficient, and it is easy to be stretched and damaged during coating, metal plating and subsequent processing; if the thickness is too high, it will increase the volume and weight of the composite film, affecting the energy density of lithium-ion batteries and other devices, and failing to meet the miniaturization requirements.

[0017] Preferably, the base film coated with polyaramid coating is subjected to double-sided metal plating to form a metal plating layer on both sides of the base film coated with polyaramid coating, wherein the thickness of the metal plating layer on one side is 1-5 μm.

[0018] Preferably, the polyaramid slurry is selected from any one of the following: (1) The polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials; (2) The polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials.

[0019] Preferably, when the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the method for preparing the double-sided metallization during the double-sided metallization process of the base film coated with the polyarylamide coating includes any one of the following steps: (1) When the metal is aluminum, the base film coated with polyarylamide coating is subjected to double-sided aluminum plating by magnetron sputtering to form an aluminum plating layer on both sides of the base film coated with polyarylamide coating. (2) When the metal is copper, the base film coated with polyarylamide coating is double-sided copper plated by magnetron sputtering or electrochemical electroplating to form copper plating layers on both sides of the base film coated with polyarylamide coating.

[0020] By adopting the above technical solution, based on the base film with conductive properties after coating, double-sided metal plating can be performed directly without a pre-plating process: When the metal is aluminum, magnetron sputtering is used for aluminum deposition. High-energy ions from magnetron sputtering bombard the aluminum target, causing aluminum atoms to detach and form high-energy metal particles. These metal particles are then uniformly deposited on both sides of a base film coated with a conductive polyarylamide coating. Since the base film already possesses conductivity and reasonable permeability, the metal particles can partially penetrate into the coating, forming an effective connection with the conductive network within the coating. This enables the aluminum layers on both sides to conduct, solving the problem of non-conductive coatings on both sides of existing non-porous base films. Simultaneously, the presence of the polyarylamide coating buffers the ion bombardment heat during magnetron sputtering, preventing shrinkage and deformation of the base film and improving the adhesion between the coating and the base film.

[0021] When the metal is copper, copper is plated using magnetron sputtering or electrochemical electroplating. In magnetron sputtering, high-energy ions bombard a copper target, causing copper particles to deposit on both sides of the coating surface. The conductive network of the coating enables conductivity between the two copper layers, while the polyaramid coating enhances adhesion and structural stability. In electrochemical electroplating, electrolysis is used, with the conductive coating-coated base film as the cathode and copper as the anode. In the electrolyte, copper ions gain electrons at the cathode (base film coating surface) and are reduced to copper atoms, uniformly depositing to form the copper plating layer. Because the base film coating already possesses good conductivity, it can be directly used as the cathode conductive carrier for electroplating, eliminating the need for pre-plating copper to form a conductive underlayer. This simplifies the process while ensuring a uniform, dense copper plating layer that bonds tightly to the coating, preventing plating peeling.

[0022] Preferably, when the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the polyarylamide slurry comprises the following raw materials in parts by weight: 1-20 parts of polyarylamide resin, 60-90 parts of solvent, and 0.1-20 parts of conductive nanomaterials.

[0023] More preferably, the polyaramid resin is at least one of meta-aramid, para-aramid, modified composite aramid, polyimide, and polyaramid anhydride.

[0024] More preferably, the solvent is at least one of dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0025] More preferably, the conductive nanomaterial is at least one of reduced graphene oxide, carbon nanotubes, and conductive carbon black.

[0026] By adopting the above technical solution, this application improves the polyarylamide slurry raw material and adds conductive nanomaterials to form a three-dimensional conductive network in the slurry, thereby reducing the volume resistivity of the coating. This eliminates the complex step of pre-plating metal to form a conductive underlayer, improves the metal plating efficiency by several times, and reduces costs.

[0027] The conductive nanomaterials added to the polyarylamide slurry coating are connected in parallel with the pore pathways to assist in conduction. Furthermore, the polar functional groups form hydrogen bonds with the base film and metal coating to strengthen the interface through metallurgical bonding. Ultimately, the double-sided metal coating achieves high-efficiency conductivity, protection, and weldability on the basis of low resistance, strong bonding, and high flatness, resulting in a composite film with low resistance, high stability, and long life.

[0028] Preferably, when the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the method for preparing the double-sided metallization during the process of double-sided metallization of the base film coated with the polyarylamide coating includes any one of the following steps: (1) When the metal is aluminum, the base film coated with polyarylamide coating is subjected to double-sided aluminum plating by magnetron sputtering to form an aluminum plating layer on both sides of the base film coated with polyarylamide coating. (2) When the metal is copper, the base film coated with polyarylamide coating is pre-plated with copper on both sides by magnetron sputtering to form a pre-plated copper layer on both sides of the base film coated with polyarylamide coating. Then, the pre-plated copper layer is pre-plated with copper on both sides by magnetron sputtering or electrochemical electroplating to form a copper plating layer on the surface of the pre-plated copper layer.

[0029] By adopting the above technical solution, this application forms a coating with high purity, high heat resistance and excellent mechanical strength by coating a polyarylamide insulating slurry that does not contain conductive nanomaterials; aluminum plating is carried out by direct deposition using magnetron sputtering, and copper plating is carried out by pre-plating a thin copper layer as a seed layer by magnetron sputtering before electroplating / sputtering, ensuring the continuity and adhesion of the metal layer on the insulating substrate. It is suitable for scenarios with high requirements for coating insulation, corrosion resistance or purity, and ensures the long-term stability of the composite film.

[0030] Preferably, when the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the polyarylamide slurry comprises the following raw materials in parts by weight: 1-20 parts of polyarylamide resin and 60-90 parts of solvent.

[0031] More preferably, the polyaramid resin is at least one of meta-aramid, para-aramid, modified composite aramid, polyimide, and polyaramid anhydride.

[0032] More preferably, the solvent is at least one of dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0033] Secondly, this application provides a double-sided metal-plated polyaramid composite film, employing the following technical solution: A double-sided metallized polyaramid composite film, wherein the double-sided metallized polyaramid composite film is prepared by the above method.

[0034] In summary, this application includes at least one of the following beneficial technical effects: This application discloses a method for preparing a polyaramid composite film with double-sided metal plating, and the polyaramid composite film. A polyaramid slurry is coated onto the outer side of a base film, and then the base film coated with the polyaramid coating is subjected to double-sided metal plating to obtain the double-sided metal-plated polyaramid composite film. This application utilizes the pore channels of the porous base film, allowing metal particles to form a through-connection during double-sided metal plating, achieving effective conductivity between the two metal plating layers. This completely solves the problem of existing non-porous substrate plating layers not being interconnected and having high overall resistance. Simultaneously, it improves the interlayer bonding strength and high-temperature resistance of the plating layers, effectively preventing battery short circuits and extending cycle life. Detailed Implementation

[0035] The technical solutions of this application are further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0036] All raw materials involved in this application are commercially available products, among which, Graphite, CAS: 7782-42-5, purchased from Aladdin; Polyimide, CAS No.: 62929-02-6; This application provides a method for preparing a double-sided metallized polyaramid composite film, comprising the following steps: A polyaramid slurry is coated on at least one side of a base film to form a polyaramid coating on at least one side of the base film; A base film coated with a polyaramid coating is subjected to double-sided metallization to obtain a double-sided metallized polyaramid composite film. Preferably, the base membrane is a porous base membrane.

[0037] Preferably, the thickness of the polyaramid coating on one side is 0.1-3 μm; Preferably, the base film includes at least one of PE, PP, and PET; Preferably, the thickness of the base film is 2-20 μm; Preferably, the air permeability of the base membrane is 10-500 Sec / 100mL; Preferably, the base film coated with polyaramid coating is subjected to double-sided metal plating to form a metal plating layer on both sides of the base film coated with polyaramid coating, wherein the thickness of the metal plating layer on one side is 1-5 μm.

[0038] Preferably, the polyaramid slurry is selected from any one of the following: (1) The polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials; (2) The polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials.

[0039] In one specific implementation scheme, when the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the specific details are as follows: When the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the preparation method for double-sided metallization of the base film coated with the polyarylamide coating includes any one of the following steps: (1) When the metal is aluminum, the base film coated with polyarylamide coating is subjected to double-sided aluminum plating by magnetron sputtering to form an aluminum plating layer on both sides of the base film coated with polyarylamide coating. (2) When the metal is copper, the base film coated with polyarylamide coating is double-sided copper plated by magnetron sputtering or electrochemical electroplating to form copper plating layers on both sides of the base film coated with polyarylamide coating.

[0040] Preferably, when the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the polyarylamide slurry comprises the following raw materials in parts by weight: 1-20 parts of polyarylamide resin, 60-90 parts of solvent, and 0.1-20 parts of conductive nanomaterials.

[0041] Preferably, the polyaramid resin is at least one of meta-aramid, para-aramid, modified composite aramid, polyimide, and polyaramid anhydride (a precursor in the synthesis of polyamide-imide (PAI)). Preferably, the solvent is at least one of dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0042] Preferably, the conductive nanomaterial is at least one of reduced graphene oxide, carbon nanotubes, and conductive carbon black.

[0043] In one specific implementation scheme, when the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the specific implementation is as follows: When the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the preparation method for double-sided metallization of the base film coated with the polyarylamide coating includes any one of the following steps: (1) When the metal is aluminum, the base film coated with polyarylamide coating is subjected to double-sided aluminum plating by magnetron sputtering to form an aluminum plating layer on both sides of the base film coated with polyarylamide coating. (2) When the metal is copper, the base film coated with polyarylamide coating is pre-plated with copper on both sides by magnetron sputtering to form a pre-plated copper layer on both sides of the base film coated with polyarylamide coating. Then, the pre-plated copper layer is pre-plated with copper on both sides by magnetron sputtering or electrochemical electroplating to form a copper plating layer on the surface of the pre-plated copper layer.

[0044] Preferably, when the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the polyarylamide slurry comprises the following raw materials in parts by weight: 1-20 parts of polyarylamide resin and 60-90 parts of solvent.

[0045] Preferably, the polyaramid resin is at least one of meta-aramid, para-aramid, modified composite aramid, polyimide, and polyaramid anhydride (a precursor in the synthesis of polyamide-imide (PAI)). Preferably, the solvent is at least one of dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0046] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0047] Raw material source:

[0048] The preparation of reduced graphene oxide follows these steps: Mix 1g of graphite and 23g of concentrated sulfuric acid for 10 minutes. Add 0.5g of sodium nitrate and 3g of potassium permanganate and mix for 10 minutes. Heat to 40℃ and react for 20 minutes. Add 150g of water and mix for 10 minutes. Heat to 90℃ and react for 20 minutes. Add 100mL of water and 1.5g of hydrogen peroxide and mix for 10 minutes. Filter and wash the filter cake thoroughly with 5% hydrochloric acid until no SO4 is found in the filtrate. 2- Centrifugation yields graphite oxide; Add 0.15g of graphene oxide to 250mL of distilled water, sonicate for 1 hour, then add 1.5g of sodium borohydride, react at 75℃ for 1.5 hours, filter, wash the filter cake with ethanol and water, centrifuge to obtain reduced graphene oxide.

[0049] Example 1:

[0050] A method for preparing a double-sided aluminum-coated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 10 kg of polyarylamide resin and 75 kg of solvent were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0051] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0052] (2) Slurry coating base film The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided aluminum plating A polyaramid-coated base film was subjected to double-sided aluminum plating using magnetron sputtering to form aluminum plating layers on both sides of the base film, ultimately resulting in a double-sided aluminum-plated polyaramid composite film.

[0053] The thickness of the aluminum plating layer on one side is 2.5 μm.

[0054] Example 2:

[0055] A method for preparing a double-sided aluminum-coated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 1 kg of polyarylamide resin and 60 kg of solvent were stirred at 500 r / min for 50 min, and then filtered through a 350 mesh screen to obtain polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0056] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0057] (2) Slurry coating base film The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided aluminum plating A polyaramid-coated base film was subjected to double-sided aluminum plating using magnetron sputtering to form aluminum plating layers on both sides of the base film, ultimately resulting in a double-sided aluminum-plated polyaramid composite film.

[0058] The thickness of the aluminum plating layer on one side is 2.5 μm.

[0059] Example 3:

[0060] A method for preparing a double-sided aluminum-coated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 20 kg of polyarylamide resin and 90 kg of solvent were stirred at 500 r / min for 50 min, and then filtered through a 350 mesh screen to obtain polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0061] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0062] (2) Slurry coating base film The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided aluminum plating A polyaramid-coated base film was subjected to double-sided aluminum plating using magnetron sputtering to form aluminum plating layers on both sides of the base film, ultimately resulting in a double-sided aluminum-plated polyaramid composite film.

[0063] The thickness of the aluminum plating layer on one side is 2.5 μm.

[0064] Example 4:

[0065] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 10 kg of polyarylamide resin and 75 kg of solvent were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0066] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0067] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A double-sided copper pre-plating method is used to pre-plat the base film coated with polyaramid coating by magnetron sputtering to form a pre-plated copper layer on both sides of the base film coated with polyaramid coating. Then, a double-sided copper plating method is used to pre-plated copper layer to form a copper plating layer on the surface of the pre-plated copper layer, and finally a double-sided copper-plated polyaramid composite film is obtained.

[0068] The total thickness of the pre-plated copper layer and the copper plating layer on one side is 2.5 μm.

[0069] Example 5:

[0070] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 1 kg of polyarylamide resin and 60 kg of solvent were stirred at 500 r / min for 50 min, and then filtered through a 350 mesh screen to obtain polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0071] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0072] (2) Slurry coating base film The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A double-sided copper pre-plating method is used to pre-plat the base film coated with polyaramid coating by magnetron sputtering to form a pre-plated copper layer on both sides of the base film coated with polyaramid coating. Then, a double-sided copper plating method is used to pre-plated copper layer to form a copper plating layer on the surface of the pre-plated copper layer, and finally a double-sided copper-plated polyaramid composite film is obtained.

[0073] The total thickness of the pre-plated copper layer and the copper plating layer on one side is 2.5 μm.

[0074] Example 6:

[0075] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 20 kg of polyarylamide resin and 90 kg of solvent were stirred at 500 r / min for 50 min, and then filtered through a 350 mesh screen to obtain polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0076] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0077] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A double-sided copper pre-plating method is used to pre-plat the base film coated with polyaramid coating by magnetron sputtering to form a pre-plated copper layer on both sides of the base film coated with polyaramid coating. Then, a double-sided copper plating method is used to pre-plated copper layer to form a copper plating layer on the surface of the pre-plated copper layer, and finally a double-sided copper-plated polyaramid composite film is obtained.

[0078] The total thickness of the pre-plated copper layer and the copper plating layer on one side is 2.5 μm.

[0079] Example 7:

[0080] A method for preparing a double-sided aluminum-coated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 10 kg of polyarylamide resin, 75 kg of solvent, and 10 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0081] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0082] The conductive nanomaterial is reduced graphene oxide.

[0083] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided aluminum plating A polyaramid-coated base film was subjected to double-sided aluminum plating using magnetron sputtering to form aluminum plating layers on both sides of the base film, ultimately resulting in a double-sided aluminum-plated polyaramid composite film.

[0084] The thickness of the aluminum plating layer on one side is 2.5 μm.

[0085] Example 8:

[0086] A method for preparing a double-sided aluminum-coated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 1 kg of polyarylamide resin, 60 kg of solvent, and 0.1 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0087] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0088] The conductive nanomaterial is reduced graphene oxide.

[0089] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided aluminum plating A polyaramid-coated base film was subjected to double-sided aluminum plating using magnetron sputtering to form aluminum plating layers on both sides of the base film, ultimately resulting in a double-sided aluminum-plated polyaramid composite film.

[0090] The thickness of the aluminum plating layer on one side is 2.5 μm.

[0091] Example 9:

[0092] A method for preparing a double-sided aluminum-coated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 20 kg of polyarylamide resin, 90 kg of solvent, and 20 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0093] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0094] The conductive nanomaterial is reduced graphene oxide.

[0095] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided aluminum plating A polyaramid-coated base film was subjected to double-sided aluminum plating using magnetron sputtering to form aluminum plating layers on both sides of the base film, ultimately resulting in a double-sided aluminum-plated polyaramid composite film.

[0096] The thickness of the aluminum plating layer on one side is 2.5 μm.

[0097] Example 10:

[0098] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 10 kg of polyarylamide resin, 75 kg of solvent, and 10 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0099] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0100] The conductive nanomaterial is reduced graphene oxide.

[0101] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A copper plating process is used to double-sided plate the base film coated with polyaramid coating, so as to form a copper plating layer on both sides of the base film coated with polyaramid coating, and finally obtain a polyaramid composite film with double-sided copper plating.

[0102] The thickness of the copper plating layer on one side is 2.5 μm.

[0103] Example 11:

[0104] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 1 kg of polyarylamide resin, 60 kg of solvent, and 0.1 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0105] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0106] The conductive nanomaterial is reduced graphene oxide.

[0107] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A copper plating process is used to double-sided plate the base film coated with polyaramid coating, so as to form a copper plating layer on both sides of the base film coated with polyaramid coating, and finally obtain a polyaramid composite film with double-sided copper plating.

[0108] The thickness of the copper plating layer on one side is 2.5 μm.

[0109] Example 12:

[0110] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 20 kg of polyarylamide resin, 90 kg of solvent, and 20 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0111] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0112] The conductive nanomaterial is reduced graphene oxide.

[0113] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A copper plating process is used to double-sided plate the base film coated with polyaramid coating, so as to form a copper plating layer on both sides of the base film coated with polyaramid coating, and finally obtain a polyaramid composite film with double-sided copper plating.

[0114] The thickness of the copper plating layer on one side is 2.5 μm.

[0115] Example 13:

[0116] A method for preparing a double-sided copper-plated polyaramid composite film includes the following steps: Step 1: Coating the base film with polyaramid slurry (1) Preparation of polyarylamide slurry: 10 kg of polyarylamide resin, 75 kg of solvent, and 10 kg of conductive nanomaterials were stirred at 500 r / min for 50 min and then filtered through a 350 mesh screen to obtain a polyarylamide slurry. The polyaramid resin is a modified composite aramid; the preparation method of the modified composite aramid includes the following steps: Under nitrogen protection, 1-butyl-3-methylimidazolium chloride ionic liquid and DMAC were mixed at a volume ratio of 13:87 and stirred until homogeneous to obtain a composite solvent. Then, 7 mol of the third monomer (6 mol of 4,4'-diaminodiphenyl ether and 1 mol of adipate diamine) was added to the composite solvent and completely dissolved. Then, 3 mol of p-phenylenediamine was added and stirred until completely dissolved. The mixture was then cooled to -10°C. Finally, 10 mol of terephthaloyl chloride was added in three portions and stirred at 1000 r / min. When the viscosity of the system increased sharply, the cooling was stopped and the reaction was allowed to continue at room temperature for 2 h. Finally, calcium hydroxide was added to adjust the pH of the system to 7. After degassing with a vacuum pump, the modified composite aramid was obtained.

[0117] The solvent is dimethylacetamide and N-methylpyrrolidone in a mass ratio of 1:1.

[0118] The conductive nanomaterial is reduced graphene oxide.

[0119] (2) Coating the base film with polyaramid slurry The polyaramid slurry is coated on both sides of the base film using a coating machine, and then cured in a coagulation bath using an immersion reverse method. It is then washed with deionized water and dried to form a polyaramid coating on both sides of the base film. The base membrane is a porous PE membrane with a thickness of 7.6 μm and an air permeability of 140 sec / 100 mL; The thickness of the polyaramid coating on one side is 0.5 μm; Step 2: Double-sided copper plating A copper plating process was used to double-sided plate a base film coated with a polyaramid coating, so as to form a copper plating layer on both sides of the base film coated with the polyaramid coating, and finally obtain a polyaramid composite film with double-sided copper plating.

[0120] The thickness of the copper plating layer on one side is 2.5 μm.

[0121] Example 14:

[0122] The difference from Example 10 is that the polyaramid resin is meta-aramid (20wt% dimethylacetamide solution of poly(m-phenylene isophthalamide)).

[0123] Example 15:

[0124] The difference from Example 10 is that the polyaramid resin is para-aramid (poly(p-phenylene terephthalamide)).

[0125] Example 16:

[0126] The difference from Example 10 is that the polyaramid resin is polyimide.

[0127] Comparative Example 1:

[0128] The difference from Example 1 is that the base membrane is a non-porous base membrane, that is, the air permeability of the base membrane is 0 Sec / 100 mL.

[0129] Comparative Example 2:

[0130] The difference from Example 4 is that the base membrane is a non-porous base membrane, that is, the air permeability of the base membrane is 0 Sec / 100 mL.

[0131] Comparative Example 3:

[0132] The difference from Example 7 is that the base membrane is a non-porous base membrane, that is, the air permeability of the base membrane is 0 Sec / 100 mL.

[0133] Comparative Example 4:

[0134] The difference from Example 10 is that the base membrane is a non-porous base membrane, that is, the air permeability of the base membrane is 0 Sec / 100 mL.

[0135] Comparative Example 5:

[0136] The difference from Example 13 is that the base membrane is a non-porous base membrane, that is, the air permeability of the base membrane is 0 Sec / 100 mL.

[0137] Performance testing:

[0138] 1. Heat shrinkage properties The double-sided metallized polyaramid composite film sample prepared in this application was degassed of residual air between the film and cut into 300*100 mm pieces along the flat area. The length A1 and width B1 of the cut sample were measured. The sample was placed in an oven at 140°C for 2 hours. After the heat treatment, the sample was taken out and allowed to cool naturally at room temperature for 10 minutes. The length A2 and width B2 of the sample were measured. The thermal shrinkage performance of the diaphragm was characterized by the longitudinal thermal shrinkage rate and the transverse thermal shrinkage rate. Longitudinal thermal shrinkage rate of diaphragm = ((A1-A2) / A1) × 100%; The transverse thermal shrinkage rate of the diaphragm is calculated as ((B1-B2) / B1)×100%.

[0139] 2. Tensile strength: The double-sided metallized polyaramid composite film sample was cut into rectangular paper pieces with a specification of 20mm×50mm along the flat area using a cutting knife. The tensile strength was tested using a servo high and low temperature tensile tester with a tensile speed of 5mm / min and a gravity sensor specification of 500kN.

[0140] Ionic conductivity: Assemble a stainless steel (SS) symmetric cell (SS|separator|SS) and test it by electrochemical impedance spectroscopy (EIS) with a frequency range of 0.1Hz-100kHz and an amplitude of 10mV.

[0141] The formula for calculating ionic conductivity (σ) is shown in the figure below: σ = d / (Rb × A); In the formula, d is the diaphragm thickness (cm), Rb is the resistance (Ω, obtained by the intercept of the high-frequency region of the EIS spectrum with the real axis), and A is the area of ​​the stainless steel electrode (cm²). 2 ).

[0142] 4. Discharge capacity: The double-sided metallized polyaramid composite film sample was assembled into a CR2032 button battery in the order of positive electrode active material, electrolyte, separator, and lithium sheet. The battery was then pressed tightly with a battery packaging machine and left to stand for more than 12 hours until the battery was fully balanced. The discharge capacity of the sample was then tested on the battery testing system to test the discharge capacity of the sample at 3C.

[0143] 5. Battery capacity retention rate: The double-sided metallized polyaramid composite film sample was assembled into a CR2032 button cell in the order of positive electrode active material, electrolyte, separator, and lithium sheet. The cell was then pressed tightly using a battery packaging machine and left to stand for more than 12 hours until it was fully balanced. After that, a charge-discharge cycle test was performed on the battery testing system with a constant current rate of 1C and a charge-discharge cutoff voltage of 2.5-3.8V. The battery capacity retention rate was recorded after 100 cycles.

[0144] Table 1 Performance Test Table Longitudinal thermal shrinkage rate (%) Transverse thermal shrinkage rate (%) Tensile strength (MPa) Ionic conductivity (S / cm) Discharge capacity (mAh) Battery capacity retention rate (%) Example 1 10.1 11.1 138 <![CDATA[6.7×10 -4 ]]> 136 81.4 Example 2 10.6 11.5 132 <![CDATA[6.5×10 -4 ]]> 132 80.1 Example 3 10.4 11.3 134 <![CDATA[6.6×10 -4 ]]> 135 80.9 Example 4 9.3 10.1 146 <![CDATA[7.1×10 -4 ]]> 141 83.5 Example 5 9.9 10.9 141 <![CDATA[6.8×10 -4 ]]> 135 81.1 Example 6 9.6 10.7 144 <![CDATA[7.5×10 -4 ]]> 138 82.5 Example 7 9.1 9.9 149 <![CDATA[7.2×10 -4 ]]> 143 85.1 Example 8 9.7 10.7 146 <![CDATA[7.0×10 -4 ]]> 140 82.2 Example 9 9.5 10.5 143 <![CDATA[7.1×10 -4 ]]> 141 83.7 Example 10 8.9 9.7 158 <![CDATA[7.6×10 -4 ]]> 154 89.1 Example 11 9.3 10.3 150 <![CDATA[7.2×10 -4 ]]> 146 84.5 Example 12 9.1 10.1 155 <![CDATA[7.4×10 -4 ]]> 147 85.5 Example 13 9.5 10.3 151 <![CDATA[7.3×10 -4 ]]> 145 83.9 Example 14 10.7 11.6 131 <![CDATA[6.7×10 -4 ]]> 130 80.3 Example 15 10.9 11.9 130 <![CDATA[6.5×10 -4 ]]> 129 80.1 Example 16 10.8 11.7 129 <![CDATA[6.6×10 -4 ]]> 127 80.2 Comparative Example 1 12.8 13.8 119 <![CDATA[5.3×10 -4 ]]> 118 75.4 Comparative Example 2 12.1 12.8 121 <![CDATA[5.6×10 -4 ]]> 120 76.5 Comparative Example 3 11.8 12.4 123 <![CDATA[5.9×10 -4 ]]> 122 77.5 Comparative Example 4 11.5 12.3 125 <![CDATA[6.1×10 -4 ]]> 123 78.7 Comparative Example 5 11.4 12.1 128 <![CDATA[6.3×10 -4 ]]> 124 79.6 The performance test results show that the double-sided metallized polyarylamide composite membranes prepared in Examples 1-16 of this application have good thermal stability, reducing the thermal shrinkage of the separator at high temperatures, thereby improving the electrochemical stability of the lithium battery. The double-sided metallized polyarylamide composite membranes prepared in this application have excellent mechanical strength and thermal shrinkage performance, effectively preventing battery short circuits and extending cycle life. The separators prepared in this application have good ionic conductivity, which does not affect the battery's discharge capacity, and the battery cycle life is also guaranteed.

[0145] Based on the test results of Example 1 and Comparative Example 1, it can be seen that the double-sided aluminum-coated polyarylamide composite film prepared in Example 1 has better overall performance than that of Comparative Example 1. This indicates that the porous base film selected in this application enables effective conduction of the metal coatings on both sides, completely solving the problem of non-conductivity and high overall resistance of the existing non-porous base coatings. At the same time, the prepared double-sided aluminum-coated polyarylamide composite film has good mechanical strength and thermal shrinkage properties.

[0146] Based on the test results of Example 4 and Comparative Example 2, it can be seen that the double-sided copper-plated polyarylamide composite film prepared in Example 4 has better overall performance than that of Comparative Example 2. This indicates that the porous substrate film selected in this application enables effective conduction of the metal coatings on both sides, completely solving the problem of non-conductivity and high overall resistance of the existing non-porous substrate coatings. At the same time, the prepared double-sided copper-plated polyarylamide composite film has good mechanical strength and thermal shrinkage properties.

[0147] Based on the test results of Example 7 and Comparative Example 3, it can be seen that the double-sided aluminum-plated polyarylamide composite film prepared in Example 7 has better overall performance than that of Comparative Example 3. This indicates that the porous base film used in this application achieves effective conductivity between the metal coatings on both sides, completely solving the problem of non-conductivity and high overall resistance of existing non-porous base coatings. The prepared double-sided aluminum-plated polyarylamide composite film has good mechanical strength and thermal shrinkage properties. At the same time, by adding conductive nanomaterials, the pre-plating process of aluminum / copper can be eliminated, improving the conductivity of the base film. The base film coated with polyarylamide slurry can be directly plated with copper.

[0148] Based on the test results of Example 10 and Comparative Example 4, it can be seen that the double-sided copper-plated polyarylamide composite film prepared in Example 10 has better overall performance than that of Comparative Example 4. This indicates that the porous base film used in this application achieves effective conductivity between the metal plating layers on both sides, completely solving the problem of non-conductivity and high overall resistance of existing non-porous base plating layers. The prepared double-sided copper-plated polyarylamide composite film has good mechanical strength and thermal shrinkage properties. At the same time, by adding conductive nanomaterials, the pre-plating process of aluminum / copper can be eliminated, improving the conductivity of the base film. The base film coated with polyarylamide slurry can be directly plated with copper.

[0149] The double-sided metallized polyarylamide composite membrane prepared in this application combines multiple advantages such as lightweight, low resistance, high temperature resistance, high adhesion, and convenient welding. It can be widely used in lithium-ion batteries, new energy storage equipment, and other fields. Compared with traditional composite membranes, it effectively improves battery energy density, extends cycle life, and significantly enhances the core competitiveness of battery products. Simultaneously, it solves many application pain points of existing composite membranes, possessing excellent prospects for industrialization and economic and social benefits. Furthermore, the porous interface and hydrophilicity of the polyarylamide composite membrane can improve the wetting efficiency of surface pretreatment solutions, reduce waste, and lower environmental pressure during production, aligning with the industry trend of green production.

Claims

1. A process for the production of a double-sided metallized polyaramid composite film, characterized by: Includes the following steps: A polyaramid slurry is coated on at least one side of a base film to form a polyaramid coating on at least one side of the base film; A base film coated with a polyaramid coating is subjected to double-sided metallization to obtain a double-sided metallized polyaramid composite film. The base membrane is a porous base membrane.

2. The method of claim 1, wherein the method is characterized by: The thickness of the polyaramid coating on one side is 0.1-3 μm; And / or, the base film includes at least one of PE, PP, and PET; And / or, the thickness of the base film is 2-20 μm; And / or, the air permeability of the base membrane is 10-500 Sec / 100 mL; And / or, the base film coated with polyaramid coating is subjected to double-sided metallization to form a metallized layer on both sides of the base film coated with polyaramid coating, wherein the thickness of the metallized layer on one side is 1-5 μm.

3. The method for preparing a double-sided metallized polyaramid composite film according to claim 1, characterized in that: The polyaramid slurry is selected from any one of the following: (1) The polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials; (2) The polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials.

4. The method for preparing a double-sided metallized polyaramid composite film according to claim 3, characterized in that: When the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the preparation method for double-sided metallization of the base film coated with the polyarylamide coating includes any one of the following steps: (1) When the metal is aluminum, the base film coated with polyarylamide coating is subjected to double-sided aluminum plating by magnetron sputtering to form an aluminum plating layer on both sides of the base film coated with polyarylamide coating. (2) When the metal is copper, the base film coated with polyarylamide coating is double-sided copper plated by magnetron sputtering or electrochemical electroplating to form copper plating layers on both sides of the base film coated with polyarylamide coating.

5. The method for preparing a double-sided metallized polyaramid composite film according to claim 3, characterized in that: When the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the preparation method for double-sided metallization of the base film coated with the polyarylamide coating includes any one of the following steps: (1) When the metal is aluminum, the base film coated with polyarylamide coating is subjected to double-sided aluminum plating by magnetron sputtering to form an aluminum plating layer on both sides of the base film coated with polyarylamide coating. (2) When the metal is copper, the base film coated with polyarylamide coating is pre-plated with copper on both sides by magnetron sputtering to form a pre-plated copper layer on both sides of the base film coated with polyarylamide coating. Then, the pre-plated copper layer is pre-plated with copper on both sides by magnetron sputtering or electrochemical electroplating to form a copper plating layer on the surface of the pre-plated copper layer.

6. The method for preparing a double-sided metallized polyaramid composite film according to claim 4, characterized in that: When the polyarylamide slurry is a polyarylamide slurry containing conductive nanomaterials, the polyarylamide slurry comprises the following raw materials in parts by weight: 1-20 parts of polyarylamide resin, 60-90 parts of solvent, and 0.1-20 parts of conductive nanomaterials.

7. The method for preparing a double-sided metallized polyaramid composite film according to claim 5, characterized in that: When the polyarylamide slurry is a polyarylamide slurry that does not contain conductive nanomaterials, the polyarylamide slurry comprises the following raw materials in parts by weight: 1-20 parts of polyarylamide resin and 60-90 parts of solvent.

8. A method for preparing a double-sided metallized polyaramid composite film according to claim 6 or 7, characterized in that: The polyaramid resin is at least one of meta-aramid, para-aramid, modified composite aramid, polyimide, and polyaramid anhydride; And / or; the solvent is at least one of dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

9. The method for preparing a double-sided metallized polyaramid composite film according to claim 6, characterized in that: The conductive nanomaterial is at least one of reduced graphene oxide, carbon nanotubes, and conductive carbon black.

10. A polyaramid composite film with double-sided metal plating, characterized in that: The double-sided metallized polyaramid composite film is prepared by the method described in any one of claims 1-9.