Patent ID: 7479758

Claim:
A battery pack comprising: a rectangular core pack having an electrode group, which includes a cathode, an anode, and a separating film, and an electrolyte mounted therein in a sealed state; a case body having an inner space for receiving the core pack; and an upper cover mounted on the case body having the core pack received therein for sealing the core pack, wherein the upper case is provided at the edge thereof with a plurality of elastic locking members, and the case body is provided at the edge thereof with a plurality of locking grooves, which correspond to the locking members of the upper case, such that the locking members of the upper case are inserted into the locking grooves of the case body while the core pack is received in the case body, whereby the upper cover is coupled to the case body, wherein each of the locking members comprises a pair of locking protrusions, which are connected to each other while a spacing groove is formed between the locking protrusions, the locking protrusions are provided at the outsides thereof with protrusions, which are formed in the shape of a downward taper, each of the locking grooves has a width less than the maximum distance between the protrusions of the locking protrusions, and wherein the upper cover is made of stainless steel, and the case body is made of a plastic material, wherein the case body is made of a plastic resin at least at the areas of the case body where the locking grooves are formed, whereby the locking protrusions inserted into the locking groove penetrate into the case body adjacent to the locking groove, and the case body conforms to the locking protrusions, by a restoring force to further increase the locking force between the locking member and the locking groove.