Patent ID: 8597809

Claim:
A rechargeable battery comprising: an electrode assembly; a battery case accommodating the electrode assembly; and a cap assembly comprising: a cap plate comprising a top portion; and a vent member comprising two or more notches and a supporting portion, wherein the vent member is configured to break at the two or more notches and bend along two or more lines adjacent to the supporting portion forming at least two openings in the cap plate; wherein the vent member is configured to form at least one flap having a length at least twice its width when the vent is broken at at least one of the notches and bent along the at least one of the lines; and wherein the at least one flap comprises an edge that contacts an edge of the top portion of the cap plate at a point further from the center of the vent than the supporting portion; wherein the cap plate comprises at least two exhaust ports wherein each of the at least two openings in the cap plate correspond to a single one of the at least two exhaust ports.