Patent ID: 7572547

Claim:
A battery pack, comprising: a plurality of battery cells; a housing substantially enclosing the plurality of battery cells; a cooling air intake port and a cooling air exhaust port defined within the housing, and at least one cooling air passage extending between the cooling air intake port and the cooling air exhaust port, wherein the at least one cooling air passage is at least partially defined by surfaces of the battery cells and an inner surface of the housing wherein the plurality of battery cells include upstream battery cells located at an upstream portion of the at least one cooling air passage and downstream battery cells located at a downstream portion of the at least one cooling air passage, the surfaces of the upstream battery cells include an upstream communication area that directly communicates with the at least one cooling air passage and upstream isolated area that is isolated from the at least one cooling air passage, the surfaces of the downstream battery cells include a downstream communication area that directly communicates with the at least one cooling air passage and downstream isolated area that is isolated from the at least one cooling air passage, and the upstream communication area of the upstream battery cells is smaller than the downstream communication area of the downstream battery cells and the upstream isolated area of the upstream battery cells is larger than the downstream isolated area of the downstream battery cells.