POWER STORAGE SYSTEM

In a power storage system, each of a plurality of power storage modules includes at least one cell, and the plurality of power storage modules are connected in series. A management device manages the plurality of power storage modules. Each of the plurality of power storage modules contains a first insulation unit having a primary side and a secondary side that are insulated from each other. The first insulation unit outputs a signal containing information of at least one cell to a communication line. The signal is referenced to predetermined standard voltage between a voltage at one end and a voltage at the other end of the plurality of power storage modules. The management device contains a second insulation unit having a primary side and a secondary side that are insulated from each other, and a circuit unit insulated from the communication line by the second insulation unit.