A ventable seal is provided for closing the open end of an electrochemical
cell. The seal incorporates indentations formed in the outer surface of
the centrally located hub that abuts a flexible diaphragm at a ventable
interface. If a cell's internal pressure reaches an unsafe level and the
seal ruptures, the indentations prevent resealing of the ruptured seal
thereby avoiding a second build up of pressure within the cell.
