Battery seal for encapsulatable cell

Claim 1

An encapsulatable electrochemical power cell comprising: a. a first cup-shaped metallic member, said cup including therein a first electrochemical reactant which together with said first member defines a first polarity electrode; b. a cover member for said first member of a second cup-shaped metal member formed of an elastically resilient material, said cup member having a base portion and side walls of a substantial height, said cover member containing a second electrochemical reactant which together with said cover member defines an electrode of opposite polarity to said first electrode; said cover member having the open end thereof of a size to be inserted partially within the open end of a said first member to define an overlap region therebetween and to leave a major portion of said side walls exposed above said overlap region; c. a grommet member of a substantially rigid material that is susceptible to cold flow positioned intermediate the first member and said cover member in the overlap region therebetween and constituting the sole material therebetween in said overlap region, said first member having the upper open end thereof formed inwardly to bear against said grommet member and thence to deform the open end of said cover member inwardly to less than its spring limit to produce an elastic spring bias of said cover member outwardly against said grommet member thereby providing a seal against loss of electrolyte from within said cell and which spring bias will follow the movement of said grommet should cold flow thereof occur to thereby maintain seal integrity; and, d. a compressible and resilient layer of material having a thickness of at least 1/16 inch extending along and around the exposed sidewall of said cover member from said seal overlap region upwardly along the major portion of the sidewall of said cover member.