ENERGY STORAGE SYSTEM

This energy storage device comprises: an energy storage body; a charging circuit configured to supply a charging current to the energy storage body; and a control unit connected to the energy storage body. This energy storage body has: a plurality of capacitor elements mutually connected in series, each having two ends; a plurality of resistors connected to the plurality of capacitor elements; and a plurality of switch elements connected to the plurality of capacitor elements and the plurality of resistors. One of the two ends of each capacitor element of the plurality of capacitor elements is connected to one end of one corresponding resistor of the plurality of resistors. The other of the two ends of each capacitor element is connected to one end of one corresponding switch element of the plurality of switch elements. The other end of the one corresponding resistor is connected to the other end of the one corresponding switch element. The one corresponding switch element is configured to be able to selectiv