Patent ID: 6127062
Filing Date: 2000-10-03
Classification: H01M,Y02E

Abstract:
In an electrochemical cell having an open ended cylindrical housing and an end cap assembly inserted therein closing said housing, said cell having a positive and a negative terminal, said end cap assembly comprising an end cap and an electrically insulating sealing member, said insulating sealing member having an elongated electrically conductive current collector passing therethrough, the current collector being in electrical contact with the end cap, said insulating sealing member electrically insulating the end cap from said housing, and the edge of said housing being crimped over the peripheral edge of said end cap to form a cell shoulder along the line of crimp, the improvement comprising:the end cap assembly comprising an end cap, and an insulating sealing member underlying said end cap when the cell is viewed in vertical position with the end cap assembly on top, wherein the insulating member electrically insulates the end cap from the cell housing; said end cap being formed of a disk of single piece metallic construction having a convoluted surface and at least one aperture through its surface; said end cap having a depressed surface around its central longitudinal axis; said insulating member comprising an insulating disk having a nonuniform thickness and having a convoluted integral surface wherein a portion of said integral surface underlies said aperture in said end cap disk when the cell is viewed in vertical position with the end cap assembly on top, said portion of said insulating disk underlying said aperture forming a rupturable membrane, wherein said rupturable membrane abuts said aperture in said end cap, whereby when gas pressure within the cell rises said rupturable membrane penetrates through said aperture and ruptures thereby releasing gas directly into the surrounding environment through said aperture.