LAMINATED POROUS FILM, BATTERY SEPARATOR AND BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a porous film which has maintaining breakdown (BD) characteristics of a polypropylene resin and has shutdown (SD) characteristics for securing battery safety as well. SOLUTION: The laminated porous film has a lamination of at least two layers of porous layers, and the one layer of the porous layers is a layer containing polypropylene resin, and the other layer is a shutdown layer composed of a composition having a crystal melting peak temperature lower than the crystal melting peak temperature of a resin composition of the layer containing the polypropylene resin and moreover has a β-activity and/or β crystallogenicity. COPYRIGHT: (C)2009,JPO&INPIT