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CN-121975116-A - Car gauge-grade electrolyte-resistant packaging material and preparation method thereof

CN121975116ACN 121975116 ACN121975116 ACN 121975116ACN-121975116-A

Abstract

The invention discloses a preparation method of a vehicle-gauge electrolyte-resistant packaging material, which comprises the steps of carrying out step-by-step copolymerization on fluorine-containing aromatic dianhydride, aromatic diamine, amino-terminated polysiloxane and diamine monomer with protected polar groups to obtain a functional polyamide-imide prepolymer solution, adding a cross-linking agent containing reversible bonds into the solution to be uniformly mixed to prepare precursor slurry, coating the precursor slurry on the surface of a base material, carrying out step heating and curing to crosslink and form a polymer to form a packaging material matrix, carrying out activation treatment on the surface of the packaging material matrix, constructing a chemical bonding barrier layer formed by an electrolyte-repellent component and an interface anchoring component on the surface of the packaging material matrix through selective grafting reaction, and carrying out thermal-chemical post treatment to stabilize the internal structure of the packaging material and activate functional side chain groups, so that the packaging material forms a complete and autonomous protection system for resisting electrolyte erosion.

Inventors

  • ZHANG LIANGHAO

Assignees

  • 广东瑞和新材料有限公司

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. The preparation method of the vehicle-gauge electrolyte-resistant packaging material is characterized by comprising the following steps of: S1, carrying out step-by-step copolymerization on fluorine-containing aromatic dianhydride, aromatic diamine, amino-terminated polysiloxane and diamine monomer with protected polar groups to obtain a functional polyamide-imide prepolymer solution, and adding a cross-linking agent with reversible bonds into the functional polyamide-imide prepolymer solution to be uniformly mixed to obtain precursor slurry; s2, coating the precursor slurry on the surface of a substrate, and carrying out step heating and curing to crosslink and shape a polymer to form a packaging material matrix; s3, carrying out activation treatment on the surface of the packaging material matrix, constructing a chemical bonding barrier layer formed by an electrolyte component and an interface anchoring component on the surface of the packaging material matrix through selective grafting reaction, and then carrying out thermal-chemical post treatment to stabilize the internal structure of the packaging material matrix and activate functional side chain groups to obtain the electrolyte-resistant packaging material.
  2. 2. The method for preparing the vehicle-gauge electrolyte-resistant packaging material according to claim 1, wherein the step-wise copolymerization reaction is carried out under the protection of inert atmosphere, the reaction temperature is controlled to be 30-80 ℃, and the reaction time is controlled to be 2-5 hours.
  3. 3. The method for preparing a vehicle-grade electrolyte-resistant packaging material according to claim 1, wherein the crosslinking agent containing reversible bonds is a furan-maleimide type dynamic covalent crosslinking agent, and the addition amount of the crosslinking agent is 5-15% of the total mass of solids in the functionalized polyamide-imide prepolymer solution.
  4. 4. The method for preparing the vehicle-gauge electrolyte-resistant packaging material according to claim 1, wherein the specific process of the stepped temperature-rising curing is that the stepped temperature-rising curing is carried out for 1-2 hours at 120+/-10 ℃, then the stepped temperature-rising curing is carried out for 2-4 hours at 180+/-10 ℃, and finally the stepped temperature-rising curing is carried out for 0.5-1.5 hours at 220+/-10 ℃.
  5. 5. The method for preparing the vehicle-grade electrolyte-resistant packaging material according to claim 1, wherein the selective grafting reaction is characterized in that an activated packaging material matrix is immersed in a solution containing alkenyl silane and a mixed solution of a perfluoroalkyl compound containing a thiol group and phosphate silane in sequence, and a thiol-ene click chemical reaction is initiated by ultraviolet light to form the chemical bonding barrier layer.
  6. 6. The method for preparing a vehicle-grade electrolyte-resistant packaging material according to claim 5, wherein in step S3, the thermal-chemical post-treatment is specifically that the packaging material with the barrier layer built is vacuum thermally annealed at 120±5 ℃ for 2-4 hours, then soaked in a weakly alkaline buffer solution at 40±5 ℃ for 20-40 minutes, and then washed and dried.
  7. 7. The method for preparing the vehicle-gauge electrolyte-resistant packaging material according to claim 1, wherein the step S1 specifically comprises the following steps: S11, in a first reactor, carrying out a pre-polycondensation reaction on fluorine-containing aromatic dianhydride and first part of aromatic diamine in a metered proportion in a polar aprotic solvent under the protection of inert atmosphere to generate a prepolymer A solution with anhydride groups at the tail end; S12, sequentially adding metered amino-terminated polysiloxane and aromatic diamine monomer with ester group-protected carboxyl into the prepolymer A solution, performing first-stage block copolymerization under preset low-temperature conditions, and introducing a flexible siloxane chain segment and a releasable group precursor into a polymer skeleton; S13, adding a second part of aromatic diamine into the reaction system, heating and performing a second-stage polycondensation reaction until the viscosity of the system is increased to a target range, so as to obtain a functional polyamide-imide prepolymer solution containing a fluorine hard segment, a siloxane soft segment and a protective side group; s14, transferring the functionalized polyamide-imide prepolymer solution into dispersing equipment, slowly adding a cross-linking agent which is dissolved in an auxiliary solvent in advance under continuous stirring, and simultaneously adding a catalytic amount of imidazole accelerator; And S15, carrying out vacuum defoaming treatment on the obtained mixed system, and filtering to remove mechanical impurities possibly existing to obtain uniform and stable precursor slurry for coating.
  8. 8. The method for preparing the vehicle-gauge electrolyte-resistant packaging material according to claim 1, wherein the step S3 specifically comprises the following steps: s31, immersing the packaging material matrix into a potassium persulfate aqueous solution with a preset concentration, and carrying out surface chemical oxidation treatment under a heating condition to generate an activated surface with hydrophilicity and a micro-roughness structure on the surface; S32, immersing the packaging material matrix subjected to the activation treatment into a first treatment liquid containing an alkenyl silane coupling agent, and carrying out pre-curing at a preset temperature after carrying out lifting and film forming so as to form a layer of bottom reaction interface rich in carbon-carbon double bonds on the surface of the matrix; s33, immersing the packaging material matrix with the surface formed with the bottom layer reaction interface into a second treatment liquid, wherein the second treatment liquid comprises a mixed solution of a perfluoroalkyl compound with a thiol group at the tail end and alkenyl silane containing a phosphate anchoring group.
  9. 9. The method for preparing a vehicle-grade electrolyte-resistant packaging material according to claim 8, wherein the step S33 further comprises: S34, irradiating ultraviolet light on the packaging material matrix immersed in the second treatment liquid, triggering thiol groups in the second treatment liquid to perform click chemical reaction with carbon-carbon double bonds on the reaction interface of the bottom layer, and simultaneously promoting hydrolytic condensation of silane components, so that a chemically bonded composite barrier layer is constructed on the surface; s35, placing the packaging material with the surface constructed with the composite barrier layer in a vacuum oven for thermal annealing treatment so as to promote densification of the barrier layer and stabilize a dynamic cross-linked structure inside the material; S36, soaking the packaging material subjected to thermal annealing in a weak alkaline buffer solution, and processing at a controlled temperature and in a controlled time to partially hydrolyze and activate the protected polar side chain groups in the material body, and finally cleaning and drying to obtain the electrolyte-resistant packaging material.
  10. 10. A vehicle grade electrolyte resistant packaging material prepared by the method of preparing a vehicle grade electrolyte resistant packaging material according to any one of claims 1 to 9, the packaging material comprising: a polymer body with a fluorine-containing chain segment, a polysiloxane flexible chain segment and a releasable polar group embedded in a molecule, wherein a dynamic reversible crosslinking structure is built in the polymer body; And a composite barrier layer bonded to the outer surface of the polymer body by chemical bonding, the composite barrier layer being composed of an electrolyte-phobic component and an interfacial anchoring component.

Description

Car gauge-grade electrolyte-resistant packaging material and preparation method thereof Technical Field The invention relates to the technical field of packaging materials, in particular to a vehicle-gauge electrolyte-resistant packaging material and a preparation method thereof. Background With the rapid development of new energy automobile industry, the power battery system evolves towards higher energy density, longer cycle life and higher safety and reliability. In this context, the performance of the packaging material used for insulation, buffering and structural fixation between the battery cells inside the battery module is critical. The material is in a harsh chemical environment rich in lithium salt electrolyte for a long time, and bears temperature change and mechanical vibration, and the stability of electrolyte corrosion resistance is directly related to long-term sealability, insulation reliability and overall service life of a battery module, so that development of a special packaging material meeting the requirements of vehicle regulations is one of key technical challenges in industry. At present, the common technical path for improving the electrolyte resistance of the polymer material in the industry mainly focuses on two types, namely, applying an additional barrier coating on the surface of a traditional packaging material (such as common epoxy resin and organic silicon) by adopting a physical coating process and introducing a solvent-resistant monomer into a molecular chain by complex chemical copolymerization. However, physical coatings tend to have limited bonding with the substrate, and are prone to interfacial delamination or coating failure under long-term thermo-mechanical stress, resulting in failure of the protection. The complex molecular synthesis generally faces the problems of complex process, high cost, difficult control of material batch stability and the like, and the stringent requirements of the vehicle-scale products on mass production consistency and cost control are difficult to meet. The prior art schemes can not fundamentally and integrally solve the core problem that the body swelling and interface protection failure collaborative occurrence caused by long-term infiltration and permeation of electrolyte of the packaging material under the dynamic electrochemical environment. In view of this, improvements in the prior art are needed to solve the technical problem that the conventional battery module packaging material is easily soaked by the electrolyte in the long-term dynamic electrochemical environment. Disclosure of Invention The invention aims to provide a preparation method of a vehicle-gauge electrolyte-resistant packaging material, which solves the technical problems. To achieve the purpose, the invention adopts the following technical scheme: The preparation method of the vehicle-gauge electrolyte-resistant packaging material comprises the following steps: S1, carrying out step-by-step copolymerization on fluorine-containing aromatic dianhydride, aromatic diamine, amino-terminated polysiloxane and diamine monomer with protected polar groups to obtain a functional polyamide-imide prepolymer solution, and adding a cross-linking agent with reversible bonds into the functional polyamide-imide prepolymer solution to be uniformly mixed to obtain precursor slurry; s2, coating the precursor slurry on the surface of a substrate, and carrying out step heating and curing to crosslink and shape a polymer to form a packaging material matrix; s3, carrying out activation treatment on the surface of the packaging material matrix, constructing a chemical bonding barrier layer formed by an electrolyte component and an interface anchoring component on the surface of the packaging material matrix through selective grafting reaction, and then carrying out thermal-chemical post treatment to stabilize the internal structure of the packaging material matrix and activate functional side chain groups to obtain the electrolyte-resistant packaging material. Optionally, the step-by-step copolymerization reaction is carried out under the protection of inert atmosphere, wherein the reaction temperature is controlled to be 30-80 ℃ and the reaction time is controlled to be 2-5 hours. Optionally, the crosslinking agent containing reversible bond is furan-maleimide dynamic covalent crosslinking agent, and the addition amount of the crosslinking agent is 5% -15% of the total mass of solids in the functionalized polyamide-imide prepolymer solution. Optionally, the specific process of the step heating solidification is that firstly, the step heating solidification is carried out for 1-2 hours at 120+/-10 ℃, then the step heating solidification is carried out for 2-4 hours at 180+/-10 ℃, and finally, the step heating solidification is carried out for 0.5-1.5 hours at 220+/-10 ℃. Optionally, the selective grafting reaction is specifically that the activated packaging material matrix is immersed