Battery pack with cooling passage

A battery pack comprising a plurality of battery modules each including a battery cell and a battery case housing the battery cell therein, the plurality of battery modules being electrically connected to each other and stacked in a stacking direction so that a cooling passage for allowing a cooling medium to flow is defined between opposed surfaces of adjacent battery cases, wherein

• one of the opposed surfaces has a plurality of first ribs projecting toward the other of the opposed surfaces and extending parallel to each other along the one of the opposed surfaces,
• the other of the opposed surfaces has a plurality of second ribs projecting toward the one of the opposed surfaces and extending parallel to each other along the other of the opposed surfaces, and
• in the cooling passage, the first ribs and the second ribs intersect each other, and end portions of the first ribs and end portions of the second ribs are in contact with each other with respect to the stacking direction.