Patent ID: 7875376

Claim:
An electrochemical cell comprising: a container having a first end, a second end, a side wall extending between the first and second ends, and an end metal wall extending across the first end; a positive electrode disposed within and in contact with said container; a negative electrode disposed in said container, within a central cavity in said positive electrode; an aqueous alkaline electrolyte disposed in said container; a pressure relief vent mechanism formed in the end metal wall of said container, away from a peripheral transition between the end wall and the side wall, for releasing internal pressure from within said container when the internal pressure becomes excessive, wherein said pressure relief vent mechanism comprises a single reduced thickness groove formed in a C-shape having first and second ends and a curved portion between the first and second ends, wherein said groove is offset from the center of the end metal wall such that the curved portion of the C-shaped reduced thickness groove midway between the ends is closer to the center of the end metal wall than are the first and second ends; and a cover with a central outward protruding nubbin disposed over the outside of the end metal wall of the container and substantially covering the pressure relief vent mechanism.