POWER SUPPLY SYSTEM FOR ELECTRIC VEHICLE, ELECTRIC VEHICLE, AND CONTROL METHOD OF POWER SUPPLY SYSTEM FOR ELECTRIC VEHICLE

A power supply system includes a main power storage device (BA) and a plurality of sub power storage devices (BB1, BB2). A converter (12B) is sequentially connected to one of the sub power storage devices (BB1, BB2) to convert voltage between the selected sub power storage device and an electric power feeding line (PL2) bidirectionally. The sub power storage device undergoes a connection switching process, and when there is no new sub power storage device remaining for replacement, then, in accordance with that sub power storage device's SOC and the vehicle's state, a request is generated to disconnect the sub power storage device. Here, when a condition regarding a temperature of at least one of the main power storage device and the plurality of sub power storage devices is satisfied, generation of a disconnection request is prohibited, in order to protect the main power storage device.