Patent ID: 8283061

Claim:
A film-encased electric device comprising: an electric device element having a positive pole tab and a negative pole tab connected thereto; encasing films having at least respective heat-sealable resin layers and which surround said electric device element with the heat-sealable resin layers that face each other, the facing heat-sealable resin layers being thermally fused to each other along outer peripheral regions thereof to provide a heat-sealed area therealong, said encasing films having an inner space therebetween that serves as an electric device element housing which accommodates said electric device element sealed therein, with said positive pole tab and said negative pole tab extending from said electric device element; and a pressure releaser disposed in a portion of said heat-sealed area on a side from which said positive pole tab and said negative pole tab extend, between said positive pole tab and said negative pole tab, or on a side different from the side from which said positive pole tab and said negative pole tab extend, said pressure releaser being arranged to allow said thermally fused encasing films to peel off progressively more preferentially therein than other regions due to internal pressure buildup in said electric device element housing; said pressure releaser having a cross-linked structure made of a cross-linked resin with a lower peel strength than the rest of the heat-sealed area and disposed in a continuous region in which said cross-linked structure has a portion exposed to said electric device element housing and another portion held in contact with ambient air.