Patent ID: 8785017

Claim:
A secondary battery comprising: an electrode assembly; a can accommodating the electrode assembly; and a cap assembly coupled to an upper portion of the can and including an upper cap that transfers a current of the electrode assembly to an exterior of the can; wherein the upper cap includes a terminal part including a first flat portion disposed at a center of the upper cap and a second flat portion extending from a periphery of the first flat portion, a peripheral part disposed at a periphery of the terminal part and stepped from the terminal part, and a connection part connecting the terminal part to the peripheral part having a gas exhausting hole wherein the gas exhausting hole comprises a first curved portion disposed at a portion where the gas exhausting hole meets the terminal part and a second curved portion disposed at a portion where the gas exhausting hole meets the connection part and the peripheral part wherein the gas exhausting hole extends through a portion of the terminal part and a portion of the peripheral part.