| 摘要 |
PROBLEM TO BE SOLVED: To easily and surely set a release pressure and a pressure releasing position when a wrapping film is expanded due to gas generated under an abnormal state. SOLUTION: The film-wrapped battery 1 has a battery element 2, and two wrapping films 4, 5 for sealing the battery element 2. The wrapping films 4, 5 contains thermally fusible resin layers and non-air-permeable layers, the thermally fusible layers are made to face each other to hold the battery element therebetween, and the battery element 2 is sealed by thermally fusing their peripheral fringe parts. A bridge structure part 8 in which the thermally fusible resin layers are bridged is formed in either one of the two wrapping films 4, 5 so as to have a part exposed to a battery element housing part and the other part making contact with the outside air in part of the region of a thermally fused part 6 formed by thermal fusion. In the bridge structure part 8, the length L1 of an inner fringe forming the fringe of the battery housing part side is longer than the length L2 of the outer fringe, or fringe making contact with the outside air. COPYRIGHT: (C)2009,JPO&INPIT
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