SECONDARY BATTERY

A secondary battery includes: a case having an internal space; an electrode assembly accommodated in the internal space of the case; a current collector electrically connected to the electrode assembly; and a cap assembly. The cap assembly includes: a cap plate sealing the case; an electrode terminal coupled to the current collector through the cap plate; and a gasket between the electrode terminal and the cap plate. The gasket has a flange portion, and the flange portion of the gasket is between an upper surface of the cap plate and the electrode terminal.