BATTERY PACK

A battery pack to be mounted on a vehicle includes a battery, a passage unit, a gas pump, a first valve, and an arithmetic and control unit. The passage unit is disposed on at least one of sides of the battery. The passage unit allows fluid to flow through an inside of the passage unit. The gas pump operates with electric power of the battery. The gas pump draws gas in the inside of the passage unit. The first valve shuts off a fluid passage through which the gas is to be supplied to the inside of the passage unit. The arithmetic and control unit controls the gas pump and the first valve, and performs a first temperature regulating process. The process includes driving the gas pump while the first valve is not shut off, and then drawing the gas from the inside of the passage unit.