SEPARATOR FOR CELL, CELL, AND METHOD FOR PRODUCING SEPARATOR

摘要

Conventionally, a separator has a function of losing its ion conductivity because melt takes place if the temperature rises when a failure such as short-circuit occurs and accordingly the sizes of pores in the separator decreases. However, the pores clog if the temperature rises to an extent and the separator itself melts, resulting in deformation such as shrinkage, making holes because of dissolution, and thereby causing dielectric breakdown. A separator (3) for a cell according to the invention free from the above problem, comprises a first porous layer (3a) mainly containing thermoplastic resin and a second porous layer (3b) formed over the first porous layer (3a) and having a heat resistance higher than that of the first porous layer (3a).