Patent ID: 8298704

Claim:
A battery gasket for sealing an opening of a battery case of a cylindrical alkaline battery, the battery gasket comprising: an injection-molded resin integral with a cylindrical boss portion having a through hole in which a current collector is inserted, a rim portion for sealing the opening of the battery case, and a connecting portion for connecting the boss portion and the rim portion, wherein the boss portion has an annular injection portion at an end face thereof, which is a trace of an injection molding gate, a ratio (S 1 /S 2 ) between an axial cross-sectional area (S 1 ) of the boss portion and an axial cross-sectional area (S 2 ) of the injection portion is in the range of 10 to 25, and an outer diameter of the boss portion is in the range of 3.0 to 4.2 mm.