Patent ID: 8426051

Claim:
A battery pack comprising: a plurality of battery cells being positioned side-by-side such that peripheral side surfaces of the battery cells are disposed closely together; a housing substantially enclosing the plurality of battery cells; a cooling air intake port and a cooling air exhaust port defined within the housing; a cooling air passage extending between the cooling air intake port and the cooling air exhaust port along an inner surface of the housing, the cooling air passage being at least partially defined by at least one peripheral side surface of the battery cells and an inner surface of the housing, whereby cooling air directly communicates with the at least one peripheral side surface of the battery cells; and a heat insulating material disposed at an upstream portion of the cooling air passage and configured to at least partially shield at least one upstream battery cell from cooling air flowing through the cooling air passage, wherein the heat insulating material comprises a relatively rigid cover disposed on the peripheral side surface of the at least one upstream battery cell.