After an alkaline secondary battery is determined to be in an over-discharge state, a battery pack is discharged while an electrolytic solution contained in the alkaline secondary battery in the over-discharge state is decomposed so that traveling using power of a motor is performed. The electrolytic solution remains in the alkaline secondary battery even when the alkaline secondary battery is in the over-discharge state. The alkaline secondary battery in the over-discharge state can be discharged and a vehicle can be allowed to travel by decomposing the electrolytic solution. In this manner, a traveling distance available during evacuation traveling of the vehicle can be increased.