US Patent 7211347 Battery packs having improved heat radiation

A battery pack (1) has a double casing structure, including an inner case (2) disposed inside an outer case (3). The inner case (2) includes a radiator plate (9) that is in contact with the side walls of battery cells (4) disposed within the battery pack (1). A forked air passage (32) extends from an air inlet (27) and is defined between the inner case (2) and the outer case (3) and along the outer surface of the radiator plate (9) until reaching a pair of air outlets (31).