Patent attributes
A film-covered electric device has an electric device element and casing films. The casing films include a sealing area formed by thermally fusing the facing surfaces of the casing films together around the periphery of the electric device element, an electric device element receiving part encapsulating the electric device element inside the sealing area, and unfused portions formed in the shape of cove communicating with the electric device element receiving part. The casing films further include a stress concentrating portion touching the unfused portions for concentrating thereon the peeling stress of the casing films generated at the sealing area by the expansion of the electric device element receiving part, and a pressure releasing part is formed in the stress concentrating portion.
