Means of providing pressure relief to sealed galvanic cell

DETAILED DESCRIPTION Briefly stated, in accordance with one aspect of the invention the foregoing objects are achieved by providing a generally tubular galvanic cell envelope with a compressively fitted end cap formed of a resilient plastic material which is resistant to attack by the cell electrolyte, and exhibits a low characteristic creep.
The end cap is provided with a pair of passages, one for tightly receiving an electrode and the other having disposed therein a plug formed of the same or a different material as the end cap.
In a preferred embodiment, the plug is formed with a hollow core, the dimensions of the core being selected to allow the plug to seat with the requisite tightness in the passage.
The outermost end of the passage is spaced from the overlying cell structure so as to allow adequate clearance for the plug.
In a preferred method of forming the cell, the end cap is made somewhat larger than the mouth of the envelope which receives it.
A molded plug is placed a predetermined depth into a vent passage in the end cap.
After the envelope is filled with electrolyte, separators and other appropriate materials the end cap is forced into the envelope mouth and tightly crimped into place.
The lateral compression of the end cap increases the frictional resistance between the plug and passage walls, so that the plug can be caused to release at a predetermined pressure.
With another embodiment the plug is made larger than the passage to provide the necessary interference in the absence of lateral compression of the end cap.