What are the preparation methods for lithium battery separators?

Lithium battery separator preparation method: dry method: polyolefin resin is melted, extruded, and blown into a crystalline polymer film. After crystallization is resolved and annealed, a highly oriented multilayer structure is obtained, which is further stretched at high temperatures. Stretching, peeling off the crystal surface to form a porous structure, which can increase the pore size of the film. Wet method: also known as phase separation method or thermally induced phase separation method, mixing liquid hydrocarbons or small molecular substances with polyolefin resin, heating and melting, forming an average mixture, then cooling for phase separation, pressing to obtain a membrane, and then The membrane is heated to a temperature close to the melting point, biaxially stretched to align the molecular chains, and finally kept for a certain period of time, and the residual solvent is eluted with volatile substances to prepare interpenetrating microporous membranes. As a key material for lithium batteries, the lithium battery separator serves as an electronic isolation function, preventing direct contact between the positive and negative electrodes, allowing lithium ions in the electrolyte to pass freely. At the same time, the separator is also crucial for ensuring the safe operation of the battery. use. Lithium battery separators have the highest technical barriers among the four materials, and their cost ratio is second only to cathode materials, about 10% to 14%. In some high-end batteries, the cost of separators can even reach 20%. The performance of the diaphragm directly affects the internal resistance, discharge capacity, cycle life and battery safety performance of lithium batteries. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the manufacturing methods for lithium iron phosphate?