Patent ID: 6531242
Filing Date: 2003-03-11
Classification: H01M,Y02E,Y02P

Abstract:
A closed battery comprising an outer container, an electrode element consisting of a positive electrode, a negative electrode, and a separator, accommodated in said outer container together with an electrolyte, and a closing member secured to an inner periphery of an open end portion of said outer container so as to close the open end portion,said closing member consisting of a valve element and a metal foil produced by continuously laminating, said valve element being formed of a metal substrate, on which a plurality of perforated openings are disposed along an endless circumference with small intervals between each opening, and said metal foil being laminated to an inner surface of the metal substrate so as to close said perforated openings, wherein portions of said small intervals between said openings formed on the metal substrate, which are transformable by a small force, are elongated so as to cause a portion of the metal substrate encircled by said plurality of perforated openings disposed on the endless circumference to be projected when internal pressure of the closed battery is increased.