POWER SUPPLY SYSTEM

A power supply system comprises: a battery pack 44 that outputs at least one of a status signal and an abnormal signal; a switch circuit 30 for connecting a storage battery control group to a power input/output line; and a sub-controller 24 that receives at least one of the status signal and the abnormal signal from the battery pack 44 and controls the switch circuit 30 by outputting a control signal to the switch circuit 30. At least part of communication between the sub-controller 24 and the battery pack 44 and at least part of communication between the sub-controller 24 and the switch circuit 30 are performed using optical fibers.