CYLINDRICAL SECONDARY BATTERY

A cylindrical secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a cylindrical case accommodating the electrode assembly and electrically connected to the second electrode plate; a terminal coupled to a lower surface of the case through a first gasket and electrically connected to the first electrode plate; a cap plate sealing the upper end of the case; and a second gasket between the case and the cap plate, the second gasket having: a sidewall portion in close contact with a side surface of the case; and a bottom portion extending inwardly from a bottom end of the sidewall portion and having at least one opening formed therein. The bottom portion of the second gasket having flange parts extending from the sidewall portion in an edge region and a bridge part connecting the flange parts to each other.