Patent ID: 8790419

Claim:
A method of manufacturing a cell separator, the method comprising: providing a water-repellent porous synthetic resin film or membrane having a large number of fine pores with a pore diameter of 1 μm or less; preparing a water-based paste comprising an aqueous solvent containing at least one type of alcohol, at least one type of granular ceramic, and at least one type of binder that is soluble or dispersible in the aqueous solvent, wherein a solids content comprising the granular ceramic and the binder in the paste is adjusted to 44% by mass to 52% by mass, and the ratio of the alcohol contained in the aqueous solvent is adjusted to 11% by mass to 36% by mass; coating the paste onto a surface of the synthetic resin film membrane; forming a protective layer mainly composed to the granular ceramic with a solids content of at least 55% by mass on the surface of the synthetic resin film or membrane by eliminating the alcohol from the paste on the surface; and drying the protective layer mainly composed of the granular ceramic on the surface.