Patent ID: 7014949

Claim:
A battery pack comprising: an outer case including first and second walls, the first wall including a draft port portion through which input cooling air is introduced, the second wall being located opposite to the first wall and including an exhaust port portion; a first row of at least 2 cylindrical lithium ion secondary batteries arranged in the outer case to face the first wall, and the first row of cylindrical lithium ion secondary batteries being spaced apart from each other; and a second row of at least 2 cylindrical lithium ion secondary batteries arranged adjacent to the first row of cylindrical lithium ion secondary batteries in the outer case, and arranged in portions facing respective spaces between the cylindrical lithium ion secondary batteries of the first row to thereby be offset with respect to the cylindrical lithium ion secondary batteries of the first row, wherein: parts of outer circumferential surfaces of the first row of cylindrical lithium ion secondary batteries, each of which is closer than any other part to the first wall, face the draft port portion of the first wall of the outer case; and parts of outer circumferential surfaces of the second row of cylindrical lithium ion secondary batteries, each of which is closer than any other part to the first wall, directly face the draft port portion of the outer case through the spaces.