The versatility of a power feeding device is improved. A power storage system includes a power storage device and a power feeding device. The power storage device includes data for identifying the power storage device. The power storage device includes a power storage unit, a switch that controls whether power from the power feeding device is supplied to the power storage unit, and a control circuit having a function of controlling a conduction state of the switch in accordance with a control signal input from the power feeding device. The power feeding device includes a signal generation circuit having a function of identifying the power storage device by the data input from the power storage device, generating the control signal corresponding to the identified power storage device, and outputting the generated control signal to the power storage device.