| abstract |
[Problem] To provide a battery packaging material which can ensure safety even when the pressure or temperature increase in a battery has progressed persistently. [Solution] A battery packaging material which is made of a laminate comprising, as the essentials, a base material layer, a metal layer and a sealant layer in this order. When a product obtained by packaging a battery element with the packaging material in a hermetically sealed state through heat sealing is heated, the packaging material delaminates at at least a part of the interface between the metal layer and the outside surface of the sealant layer with the hermetically sealed state being kept, and thereafter works so as to make the product unsealed. |