End cap seal assembly for a lithium cell

An end cap assembly for a primary lithium cell is disclosed. The end cap has a principal application in closing and sealing a primary lithium cell having wound electrodes. The cell may typically have an anode comprising lithium and a cathode comprising iron disulfide (FeS2). The end cap assembly has a metal cathode contact cup therein having a closed end and opposing open end with integral side walls therebetween. The cathode contact cup is electrically connected to the cathode and is within the electrical pathway between the cathode and terminal end cap. The cathode contact cup has one or more grooves formed at the closed end thereof resulting in thinned or rupturable portions of remaining metal underlying said grooves. The thin or rupturable remaining metal portions are exposed directly to gas within the cell interior and are designed to rupture when gas within the cell builds to a predetermined level.