SECONDARY BATTERY

A secondary battery includes: a cylindrical case; an electrode assembly accommodated in the cylindrical case and wound in a cylindrical shape; and a current interrupt device electrically connected to the electrode assembly and sealing the cylindrical case. The current interrupt device includes a cap-down electrically connected to the electrode assembly, a safety vent electrically connected to the cap-down, and an insulating gasket between the cap-down and the safety vent and covering outer circumferences of the cap-down and the safety vent.