OUTER CASING MATERIAL FOR BATTERY AND LITHIUM SECONDARY BATTERY

PURPOSE: The present invention provides a battery exterior which can exhibit an excellent property of electrically insulating of an internal base material layer. The battery exterior, in which an internal layer includes the base material layer and a sealant layer, is configured to present excellent electrical insulating and heat sealing properties. CONSTITUTION: A battery exterior (4) is made by interposing a bonding layer between an outer layer (11), a thin metal layer (10) and an internal layer. The internal layer has a base material layer and a sealant layer which contains propylene-ethylene random copolymers with the melt flow rate within the range of 3-30 g/10 mins at room temperature and a resin composition with the melt flow rate within the range of 0.1-15 g/10 mins at room temperature. The resin composition comprises as 50-80% by weight of polypropylene (A) and as 20-50% by weight of propylene and ethylene (B) or/and 50-85% by weight of propylene-ethylene polymerization unit of copolymers, as copolymer elastomers with C4-12 α-olefin.