Production process of lithium iron battery diaphragm
The production process of lithium iron battery separators is mainly divided into dry stretching and wet stretching. The many characteristics that lithium-ion battery separators must have, put forward special requirements for their production process, and the production process includes raw material formula and rapid formula adjustment, micropore preparation technology, and independent design of complete equipment.
The dry uniaxial stretching process is a method of producing hard elastic fibers to prepare highly oriented polypropylene or polyethylene films with low crystallinity. In the high-temperature annealing process, a film with high crystallinity is obtained. This film is first stretched at low temperature to form micro-defects, and then at high temperature the defects are pulled apart to form micro-pores. At present, more than one-third of my country's output uses the dry double-drawing process, and products occupy a large proportion in the low-end market.
The wet production process is also called phase separation or thermally induced phase separation. The wet process mixes liquid hydrocarbons or some small molecular substances with polyolefin resins, heats and melts to form a uniform mixture, and then cools down for phase separation and compression Obtain the membrane, and then heat the membrane to a temperature close to the melting point, perform bidirectional stretching to align the molecular chains, and finally keep it warm for a certain period of time, eluting the residual solvent with volatile substances, and prepare interpenetrating microporous membrane materials.