Patent ID: 8178235

Claim:
A rechargeable battery comprising: an electrode assembly comprising a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode; a case housing the electrode assembly and having an open end for receiving the electrode assembly into the case, the case comprising a case wall having a wall end surface at the open end; and a cap plate closing the open end and comprising a base surface parallel to and contacting the wall end surface, an outside surface located outside the case and opposite the base surface, and an inclined outer edge surface having an outer end attached to the wall end surface, the inclined outer edge surface being inclined outwardly and extending from the outside surface to the base surface, wherein the cap plate is welded at the outer end to the wall end surface and seals the case at the outer end, wherein the outer end is spaced apart from a wall outer edge of the wall end surface around a circumference of the rechargeable battery, and wherein an angle between the inclined outer edge surface and the base surface is greater than 0° and less than 90°.