Sealing film for packaging material of an energy storage device, packaging material for energy storage device and energy storage device

摘要

A sealing film has a structure made of a laminated body of two or more layers. The laminated body contains a first resin layer 7 comprising 50 mass% or more of a random copolymer containing propylene and a copolymer component other than propylene as copolymer components, and a second resin layer 8 formed of a mixed resin containing a first resin elastomer-modified olefin-based resin having a crystallization temperature of 105 ° C or more and a crystallization energy of 50 J / g or more, and a second elastomer-modified olefin-based resin having a crystallization temperature of 85 ° C or more and a crystallization energy of 30 J / g or less. With this structure, when the internal pressure of an energy storage device is excessively increased, breakage (separation) occurs in the interior of the sealing layer, thereby releasing gases, which in turn can prevent bursting of the packaging material due to an increase in internal pressure.