An electric power storage system for a vehicle, the vehicle including a motor for moving the vehicle, and a battery configured to supply electric power to the motor, the battery being adapted to be charged with external power supplied from an external power supply, the electric power storage system comprises: a temperature sensor configured to detect a temperature of the battery; a battery heater configured to raise the temperature of the battery; a charger that is connectable with the external power supply, and is configured to deliver the external power to the battery and the battery heater, respectively; characterized in comprising a controller configured to perform charge control and temperature regulation control when the temperature of the battery is equal to or lower than a predetermined temperature, the charge control being control for charging the battery with the external power, the temperature regulation control being control for supplying a part of the external power to the battery heater and raising the temperature of the battery when the temperature of the battery is equal to or lower than the predetermined temperature, the controller being configured to perform control for supplying a first electric power to the battery heater when a state of charge of the battery is larger than a predetermined value and the temperature of the battery is equal to or lower than the predetermined temperature, and the controller being configured to perform control for supplying a second electric power to the battery heater when the state of charge of the battery is equal to or smaller than the predetermined value and the temperature of the battery is equal to or lower than the predetermined temperature, the first electric power being smaller than the second electric power. a temperature sensor configured to detect a temperature of the battery; a battery heater configured to raise the temperature of the battery; a charger that is connectable with the external power supply, and is configured to deliver the external power to the battery and the battery heater, respectively; characterized in comprising a controller configured to perform charge control and temperature regulation control when the temperature of the battery is equal to or lower than a predetermined temperature, the charge control being control for charging the battery with the external power, the temperature regulation control being control for supplying a part of the external power to the battery heater and raising the temperature of the battery when the temperature of the battery is equal to or lower than the predetermined temperature, the controller being configured to perform control for supplying a first electric power to the battery heater when a state of charge of the battery is larger than a predetermined value and the temperature of the battery is equal to or lower than the predetermined temperature, and the controller being configured to perform control for supplying a second electric power to the battery heater when the state of charge of the battery is equal to or smaller than the predetermined value and the temperature of the battery is equal to or lower than the predetermined temperature, the first electric power being smaller than the second electric power. perform charge control and temperature regulation control when the temperature of the battery is equal to or lower than a predetermined temperature, the charge control being control for charging the battery with the external power, the temperature regulation control being control for supplying a part of the external power to the battery heater and raising the temperature of the battery when the temperature of the battery is equal to or lower than the predetermined temperature, the controller being configured to perform control for supplying a first electric power to the battery heater when a state of charge of the battery is larger than a predetermined value and the temperature of the battery is equal to or lower than the predetermined temperature, and the controller being configured to perform control for supplying a second electric power to the battery heater when the state of charge of the battery is equal to or smaller than the predetermined value and the temperature of the battery is equal to or lower than the predetermined temperature, the first electric power being smaller than the second electric power.