Patent ID: 8920959

Claim:
A lithium ion battery outer cover material, comprising: sequentially laminating onto one side of a base material layer (SB) a first adhesive layer (AD- 1 ) containing an adhesive, an aluminum foil layer (AL) provided with a corrosion prevention treated layer (CL) on at least one side thereof, a second adhesive layer (AD- 2 ) containing an adhesive or adhesive resin, and a sealant layer (SL); wherein, the base material layer (SB) has a film base material (A) as indicated below: film base material (A): film base material in which the difference (α 2 −α 1 ) between elasticity to the yield point (α 1 ) and elasticity to the rupture point (α 2 ) as measured according to JIS-K7127 is 100% or more in at least one of the MD direction and TD direction.