Patent ID: 7267906
Filing Date: 2007-09-11
Classification: H01G,H01M,Y02E,Y10T

Abstract:
1. A film-covered electric device having an electric device element, and a casing film arranged for enclosing said electric device element to seal said electric device element, said casing film comprising: a sealing area formed by thermally fusing the facing surfaces of said casing film together throughout the perimeter of said casing film around the periphery of said electric device element; an electric device element receiving part formed inside said sealing area as a space for encapsulating said electric device element; at least one unfused portion communicating with said electric device element receiving part, and having a cove shape that opens to said electric device element receiving part; a sealed stress concentrating portion touching said unfused portion and which concentrates the peeling stress of said casing film, the peeling stress being generated by the expansion of said electric device element receiving part according to the rise of inside pressure of said electric device element receiving part; and a pressure release part formed within said sealed stress concentrating portion for opening the inside of said electric device element receiving part to the outside thereof by peeling said casing film at said sealed stress concentrating portion, wherein two unfused portions are provided in spaced relationship with each other along the periphery of said sealing area, and said sealed stress concentrating portion is located between said two unfused portions, wherein said sealed stress concentrating portion is formed as an island-shaped fused portion located between said two unfused portions.