Patent attributes
A rechargeable battery including an electrode assembly; a case accommodating the electrode assembly; and a cap assembly coupled with an opening of the case with a gasket between the cap assembly and the case, wherein the cap assembly includes a vent plate that is electrically connected to a cap plate; a middle plate that is separated from the vent plate, that includes a through-hole that is penetrated by a vent protruding from the vent plate, and that is electrically connected to the second electrode; an insulator interposed between the vent plate and the middle plate; and a sub-plate electrically connecting the vent with the middle plate, wherein at least one of the vent plate or the middle plate includes a protrusion and a groove facing the insulator, the protrusion being coupled with a complementary groove in the insulator and the groove being coupled with a complementary protrusion in the insulator.