Patent ID: 8802263

Claim:
A battery pack, comprising: a battery; and a plurality of metal cases surrounding the battery, wherein the plurality of metal cases includes a first metal case and a second metal case and the first and second metal cases are welded to each other, wherein the battery includes: a first surface and a second surface defined by the directions of width and thickness; a third surface and a fourth surface defined by the directions of height and thickness; a fifth surface and a sixth surface defined by the directions of width and height; a frame surrounding the first to fourth surfaces, the frame including an opening exposing the fifth surface and an opening exposing the sixth surface; and a protective circuit module between the first surface and the frame, wherein the first metal case includes: a first plate covering the fifth surface; and a second plate covering the third surface and a third plate covering the fourth surface, and wherein the second metal case includes: a fourth plate covering the sixth surface; and a fifth plate covering the third surface and a sixth plate covering the fourth surface.