<p>A battery pack in which cells (1) are arranged is configured so that: each of the cells (1) has a discharge opening (114) for discharging gas in one direction, the gas being generated in the cell (1); the cells (1) are arranged as units each consisting of two of the cells (1); and the two of the cells (1) are arranged so that the directions of the gas discharged from the discharge openings (114) of the cells (1) face each other.</p>
