The invention provides a battery
coating film
slurry, a battery separator, a secondary battery and their respective preparation methods. The preparation of the battery
coating film
slurry includes: providing a
polymer unit, the
polymer unit comprising vinylidene
fluoride and a
fluorine-containing
polymer unit , providing a nucleating agent, adding the nucleating agent during the
polymerization of the
polymerization unit to obtain a modified polymer; and preparing the battery
coating film
slurry based on the modified polymer. Through the above technical solution, the present invention designs the battery coating film slurry, and adopts a non-aqueous
system, which can not only bond the diaphragm and the
pole piece together, improve the
hardness of the battery, but also the
crystal form of the polymer prepared
Polar crystal transformation, more complete
crystal structure and higher
crystallinity, smaller
swelling ratio, better bonding performance; the manufactured battery has smaller
internal resistance and better cycle performance. The water-based
system is used to disperse the polymer, which solves the shortcomings of the oil-based
system for preparing copolymers, gives full play to the advantages of water-based
polymer coating products, and further improves the
environmental protection effect.