Patent ID: 11394083

Abstract:
A secondary battery separator including a porous substrate and a porous film firmly bonded to each other, the porous film being disposed on or above the porous substrate. The porous film contains a fluorine-containing polymer that contains a polymerized unit based on vinylidene fluoride, a polymerized unit based on tetrafluoroethylene, and a polymerized unit based on a monomer represented by the following formula (2-2): R5R6C═CR7R8CO2Y1  (2-2) wherein R5, R6, and R7 are each independently a hydrogen atom or a C1-C8 hydrocarbon group; R8 is a C1-C8 hydrocarbon group; and Y1 is an inorganic cation and/or an organic cation. Also disclosed is a secondary battery including the secondary battery separator; a positive electrode; a negative electrode; and a non-aqueous electrolyte solution.