Patent ID: 8497033

Claim:
A prismatic battery, comprising: an electrode assembly including electrode plates and a separator, the separator being wound between the electrode plates; a can defining a space receiving the electrode assembly; and a cap plate covering the space, the cap plate being configured to deform away from the space when predetermined sides of the can are deformed toward the space, wherein a hole is defined through the cap plate in a center region thereof, wherein the electrode assembly further includes an electrode terminal disposed through the hole such that an upper portion thereof is exposed at an exterior of the prismatic battery, the electrode terminal being electrically coupled to one of the electrode plates via a terminal plate and being electrically insulated from the cap plate, wherein the cap plate has at least two stepped portions extending away from the space, the at least two stepped portions: forming one concave feature around the center region including a center portion on which the hole is formed, and offsetting the center region from peripheral regions of the cap plate such that a distance from the center region to the space is greater than a distance from the peripheral regions to the space, wherein each stepped portion has a side surface inclined at an angle with respect to a major surface of the cap plate, and wherein the terminal plate and the electrode terminal are coupled to the cap plate, the terminal plate and a lower portion of the electrode terminal being disposed between the concave feature and the electrode assembly.