SEPARATOR FOR POWER STORAGE DEVICE, AND NONAQUEOUS ELECTROLYTE BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a separator for a power storage device which has a good cycle characteristic, and a good trickle characteristic and which never worsens in battery characteristics even if it is operated over a long period of time.SOLUTION: A separator for a power storage device comprises: a polyolefin resin porous film; and a porous layer on at least one face of the polyolefin resin porous film, which includes an inorganic filler and a resin binder. In the separator for a power storage device, the ratio D(MD)/D(TD) of the Li ion diffusion coefficient of the polyolefin resin porous film in MD direction to that in TD direction is 2.0-5.0.SELECTED DRAWING: None