BUTTON-TYPE SECONDARY BATTERY

A button-type secondary battery having a cup which has an opened upper side and in which an electrode assembly and an electrolyte are mounted; a top plate which is coupled to an upper end of the cup to close the opened upper side of the cup and in which a through-hole is formed; a positive electrode terminal including a protrusion having a diameter capable of being inserted into the through-hole and a hook having a diameter greater than that of the through-hole, the protrusion being inserted into the through-hole so that the hook is disposed outside or inside the cup; and a gasket inserted to insulate a portion at which the protrusion and the hook are in contact with the top plate when the protrusion of the positive electrode terminal is inserted into the through-hole. The gasket bonds the positive electrode terminal to the top plate.