Patent ID: 8003242

Claim:
A liquid retaining pressure relief valve for use in an electrochemical battery cell having a cell cover comprising, in combination: a valve housing including a gas passageway extending between opposite ends thereof; a pressure regulator assembly sealably mounted in one of said opposite ends of said valve housing, said pressure regulator assembly including a regulator body having a center bore communicating with at least one vent channel for venting gasses passing through said gas passageway to the ambient atmosphere, and an elastomer band covering said at least one venting channel and on an exterior surface of said regulator body; and a membrane vent assembly sealably mounted in the other opposite end of said valve housing which directs gasses into said gas passageway from the interior of said battery cell, said membrane vent assembly including a hollow vent body having a larger outer diameter ring shaped lower section and a smaller outer diameter ring shaped upper section mounted within said gas passageway of said valve housing, a cupped shaped cap mounted beneath said larger diameter lower section forming together with said larger diameter lower section a vent chamber communicating with said gas passageway in said valve housing and having a plurality of slots radially disposed around said vent chamber, and a gas permeable liquid repellant membrane extending entirely across said vent chamber and having its outer edges embedded and liquid tightly sealed within said vent body, said slots allowing gas to enter into said vent chamber while substantially restricting the passage of liquid.