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CN-121983750-A - Ceramic diaphragm with low surface density and high liquid absorption and retention performance and preparation method thereof

CN121983750ACN 121983750 ACN121983750 ACN 121983750ACN-121983750-A

Abstract

The invention discloses a ceramic diaphragm with low surface density and high liquid absorption and retention performance and a preparation method thereof, wherein the ceramic diaphragm with low surface density and high liquid absorption and retention performance comprises the following components: the preparation method of the slurry comprises the steps of mixing porous glass, water, a dispersing agent, a functional auxiliary agent, a thickening agent, an adhesive and a wetting agent uniformly to obtain the slurry, wherein the functional auxiliary agent is a cellulose nanocrystal solution. The ceramic diaphragm with low surface density, high liquid absorption and retention performance has excellent liquid absorption rate, liquid retention rate, breakdown voltage, needling strength and heat resistance.

Inventors

  • WANG LIANGLIANG
  • YUAN HAICHAO
  • XU FENG
  • Su bihai
  • TIAN HAILONG
  • WANG TENGFEI

Assignees

  • 河北金力新能源科技有限公司

Dates

Publication Date
20260505
Application Date
20260120

Claims (10)

  1. 1. A ceramic diaphragm with low surface density and high liquid absorption and retention performance is characterized by comprising a base film and a coating on the base film, wherein the coating is obtained by coating slurry, the method for preparing the slurry comprises the steps of mixing porous glass, water, a dispersing agent, a functional auxiliary agent, a thickening agent, an adhesive and a wetting agent uniformly to obtain the slurry, wherein the functional auxiliary agent comprises cellulose nanocrystals, and the ratio of the porous glass, the water, the dispersing agent, the functional auxiliary agent, the thickening agent, the adhesive and the wetting agent is (20-28) to (30-42) to (0.6-1.2) to (3-6) to (2-5) to (1.5-3.0) to (0.03-0.06) in parts by weight.
  2. 2. The ceramic membrane of claim 1, wherein the dispersant is an acrylate copolymer solution, the thickener is a carboxymethyl cellulose solution, the binder is an acrylic acid copolymer emulsion, and the wetting agent comprises alkylphenol ethoxylates.
  3. 3. The ceramic separator according to claim 1, wherein the porous glass is borosilicate porous glass having a porosity of 20% to 70% and a specific surface area of 50 to 500m 2 /g.
  4. 4. The ceramic separator according to claim 2, wherein the acrylate copolymer solution has a solids content of 45-55wt%.
  5. 5. The ceramic membrane of claim 2, wherein the acrylic copolymer emulsion has a solids content of 54 to 56wt%.
  6. 6. The method for preparing the ceramic membrane with low surface density and high liquid absorption and retention performance according to claim 1, which is characterized by comprising the steps of coating slurry on a base membrane, drying, and obtaining a coating on the base membrane to obtain the ceramic membrane with low surface density and high liquid absorption and retention performance.
  7. 7. The method according to claim 6, wherein the thickness of the single-sided coating is 2-4 μm.
  8. 8. The method according to claim 6, wherein the slurry has a particle size d50=0.6 to 0.8 μm and d90=1.8 to 2.4 μm, and the slurry has a viscosity of 60 to 130 mPa.s at 25 ℃.
  9. 9. The porous glass and the functional auxiliary agent are applied to cooperatively improve the liquid absorption rate and the liquid retention rate of the diaphragm.
  10. 10. The application of porous glass and functional auxiliary agent to synergistically improve the heat resistance of a diaphragm.

Description

Ceramic diaphragm with low surface density and high liquid absorption and retention performance and preparation method thereof Technical Field The invention belongs to the technical field of battery diaphragms, and particularly relates to a ceramic diaphragm with low surface density and high liquid absorption and retention performance and a preparation method thereof. Background The environmental protection problem is more serious in the current society, the development of clean energy becomes a future development trend, and the safety of electric automobiles as an important new energy industry is receiving more and more social attention. The safety, the cruising ability and the like of the lithium ion battery serving as a power source of an electric automobile are important in scientific research, and the performance of the lithium ion battery serving as a diaphragm of one of key inner layer components of the lithium ion battery determines the interface structure and the internal resistance value of the battery, so that the capacity, the circulation and the safety performance of the battery are directly influenced. In a lithium ion battery, after the separator sucks electrolyte, the separator can prevent the battery from being short-circuited and simultaneously allow the conduction of lithium ions, and when the battery is overcharged or the temperature is raised, the separator blocks the conduction of current through closed pores to prevent explosion. The common diaphragm is a ceramic diaphragm, the coating of the ceramic diaphragm is inorganic particles such as boehmite, alumina and the like, and the ceramic diaphragm formed by the ceramic diaphragm has higher surface density, so that the weight of the battery is higher, and the liquid absorption and retention performance is poorer. In addition, the compatibility of the coating formed by inorganic particles such as boehmite, alumina and the like with a base film is poor, and a large amount of adhesive is needed to be added, so that not only can the pore of a diaphragm be blocked, the liquid absorption rate be reduced, but also the contact resistance of a battery can be increased, the coating is easy to fall off and fall off powder, and finally the battery is caused to fail. Meanwhile, the ceramic particles have small specific surface area and compact accumulation, the liquid retaining capacity is attenuated after the ceramic particles are processed into a polar group, and the battery is easy to generate lean liquid phenomenon in long circulation, so that the service life and the safety of the battery are influenced. Based on the above, the invention provides the composite coating diaphragm with low surface density and high liquid absorption and retention performance, which is favorable for obtaining a lightweight lithium ion battery. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a ceramic diaphragm with low surface density and high liquid absorption and retention performance. The invention also aims at providing a preparation method of the ceramic diaphragm with low surface density and high liquid absorption and retention performance. The aim of the invention is achieved by the following technical scheme. The ceramic diaphragm with low surface density and high liquid absorption and retention performance comprises a base film and a coating on the base film, wherein the coating is obtained by coating slurry, and the method for preparing the slurry comprises the steps of mixing porous glass, water, a dispersing agent, a functional auxiliary agent, a thickening agent, an adhesive and a wetting agent uniformly to obtain the slurry, wherein the functional auxiliary agent is a Cellulose Nano Crystal (CNC) solution, and the ratio of the porous glass, the water, the dispersing agent, the functional auxiliary agent, the thickening agent, the adhesive and the wetting agent is (20-28) to (30-42) to (0.6-1.2) to (3-6) to (2-5) to (1.5-3.0) to (0.03-0.06) in parts by weight. In the technical scheme, the dispersing agent is an acrylic ester copolymer solution, the thickening agent is a carboxymethyl cellulose solution, the adhesive is an acrylic acid copolymer emulsion, and the wetting agent comprises alkylphenol ethoxylates. In the technical scheme, the porous glass is borosilicate porous glass, the porosity of the porous glass is 20% -70%, the specific surface area is 50-500 m 2/g, and the pore diameter is 5-20 nanometers. In the technical scheme, the particle size of the porous glass is 0.5-3 mu m. In the technical scheme, the solid content of the acrylate copolymer solution is 45-55wt%. In the above technical solution, the solid content of the Cellulose Nanocrystal (CNC) solution is 10wt%. In the above technical scheme, the solid content of the carboxymethyl cellulose solution is 5wt%. In the technical scheme, the solid content of the acrylic copolymer emulsion is 54-56wt%. The preparation method of the ceramic membran