POWER SUPPLY DEVICE

A power supply device includes a plurality of batteries and an exterior case. Each battery includes an exhaust valve that opens if an internal pressure becomes higher than a predetermined pressure. The exterior case accommodates the batteries. The exterior case includes a collision-enhancing type gas-releasing path that releases a gas discharged through the exhaust valve to the outside. The collision-enhancing type releasing path includes first and second collision plates. The gas discharged through the exhaust valve collides against the first and second collision plates and is then released to the outside of the exterior case. The first collision plate reflects a flowing direction of the gas discharged through the exhaust valve in collision of the gas against a surface of the first collision plate. The second collision plate faces the first collision plate.