Patent ID: 6887614

Claim:
An electrochemical cell comprising an open ended cylindrical housing and an end cap assembly inserted therein closing said housing, said end cap assembly comprising a support disk comprising metal and an underlying electrically insulating sealing disk when the cell is viewed in vertical position with the end cap assembly on top, wherein said support disk has a downwardly extended surface, said downwardly extended surface extending downwardly from a high point thereon to low point thereon, said downwardly extended surface being slanted at an angle of between 40 and 80 degrees from the cell's central longitudinal axis so that said high point is closer to the cell's central longitudinal axis than said low point when the cell is viewed in vertical position with the end cap assembly on top, said downwardly extended surface having at least one aperture therethrough, wherein said sealing disk comprises plastic material and has a downwardly extending wall abutting said downwardly extended surface of said support disk on the side thereof facing the cell interior, wherein said abutting wall of said sealing disk has a groove on its inside surface facing the cell interior, said groove forming a rupturable membrane abutting said aperture, whereby when gas pressure within the cell rises, said rupturable membrane penetrates through said aperture and ruptures thereby releasing gas into the surrounding environment through said aperture.