Patent ID: 8212398

Claim:
A power supply device having a plurality of power storage devices connected in parallel, comprising: temperature detection units for detecting temperatures of each of the plurality of power storage devices; switch elements respectively connected to each of the plurality of power storage devices in series; and a control unit for controlling ON and OFF states of each of the switch elements, wherein the control unit performs a temperature control for increasing a time ratio of the OFF state in controlling the ON and OFF states of each of the switch elements based on each of the temperatures detected by the temperature detection units, and wherein the control unit starts the temperature control if a temperature detected by one of the temperature detection units exceeds a start-control temperature, and the control unit stops the temperature control when a temperature detected by the temperature detection unit falls below a cancel-control temperature which is lower than the start-control temperature, or the control unit starts the temperature control if a temperature detected by one of the temperature detection units exceeds a control determination temperature, and the control unit stops the temperature control when a time elapsed after a temperature detected by the temperature detection unit falls below the control determination temperature reaches a control determination time.