Patent ID: 7511455

Claim:
A power supply unit mountable in a vehicle, comprising: a battery pack accommodating a battery module including a plurality of battery cells, said battery module being formed in said battery pack to include a plurality of layered battery groups which include said plurality of battery cells, a component box accommodating an electric component electrically connected to said battery module, said component box having a shape of a substantially flat plate, and a cooling device for supplying a coolant to said battery module to cool down said battery module, wherein said battery pack includes a casing as an exterior material for said battery module, said battery pack further includes a coolant passage through which said coolant passes between an outer surface of said battery module and said casing, a contacting surface of said component box is placed in substantial contact along the contacting surface with one of longitudinally extending side surfaces of said casing, said side surfaces extending in a direction in which said plurality of layered battery groups are layered among the plurality of side surfaces of said casing, thereby placing said component box in contact with the coolant passage through the contacting surface, and said component box is placed with a center thereof positioned at a central portion of said side surface of said casing extending in the direction in which said plurality of layered battery groups are layered, such that heat exchange of increased uniformity over said plurality of layered batteries occurs between said component box and said battery pack through the contacting surface without transfer of any coolant from the cooling device into the component box.