SECONDARY BATTERY AND MANUFACTURING METHOD OF SECONDARY BATTERY

The present invention relates to a secondary battery, which has a simplified cap assembly structure to ensure an inner space, and thus can have increased capacity. Disclosed in one embodiment is a secondary battery comprising: an electrode assembly; a case for accommodating the electrode assembly; and a cap assembly coupled to the top of the case and electrically connected to the electrode assembly, wherein the cap assembly comprises: a cap plate having a ring-shaped first groove formed on the upper surface thereof, and a ring-shaped second groove formed on the lower surface thereof and connected to the first groove; and an insulation member insert-injected into the first groove.