POWER STORAGE SYSTEM

IDs are appropriately assigned to a plurality of slave devices. A power storage system includes: a master device including a first controller, and a pair of first communication terminals; and a slave device including a second controller, a pair of second communication terminals, and a battery unit, wherein the slave device includes a pair of first switches series-connected to the pair of second communication terminals; the pair of first communication terminals and the pair of second communication terminals are connected to each other; when the slave device is notified of a predetermined communication signal from the master device, the second controller controls and turns the pair of first switch from on to off; and the first controller assigns an ID to the slave device.