Management device and power supply system

1. A management device comprising:

a plurality of sub-management units that respectively manage a plurality of power storage modules each including a plurality of cells connected in series; and

a main management unit that manages the plurality of power storage modules via the plurality of sub-management units, wherein

the main management unit and the plurality of sub-management units are daisy-chain connected by a power line,

the main management unit is configured to supply DC power from a power storage unit other than the plurality of power storage modules to the plurality of sub-management units via the power line, wherein the power line is configured to transmit the DC power therethrough,

each of the main management unit and the plurality of sub-management units includes a communication unit, and

each communication unit superimposes a communication signal on the DC power transmitted through the power line.

2. The management device according to claim 1 , wherein

each of the plurality of sub-management units further includes:

a voltage detection circuit that detects a voltage of each of the plurality of cells included in a corresponding one of the plurality of power storage modules; and

an equalization circuit that equalizes capacities/voltages of the plurality of cells included in the corresponding one of the plurality of power storage modules, and

the communication unit transmits the voltages of the plurality of cells detected by the voltage detection circuit to the main management unit via the power line, and receives a control signal for controlling the equalization circuit from the main management unit via the power line.

3. The management device according to claim 2 , wherein

each of the plurality of sub-management units further includes a direct current-direct current converter that converts a DC voltage supplied from a power storage unit other than the plurality of power storage modules via the power line, into a predetermined DC voltage, and

the equalization circuit charges, among the plurality of cells included in the corresponding one of the plurality of power storage modules, a cell designated by the control signal with a DC voltage converted by the direct current-direct current converter.

4. The management device according to claim 1 , wherein each of the plurality of sub-management units further includes

a first signal wiring that connects a first connection point of the power line and a first communication terminal of the communication unit,

a second signal wiring that connects a second connection point of the power line and a second communication terminal of the communication unit,

a first insulating circuit that is inserted in the first signal wiring for insulating between the first connection point and the first communication terminal in terms of DC,

a second insulating circuit that is inserted in the second signal wiring for insulating between the second connection point and the second communication terminal in terms of DC, and

a low-pass filter inserted between the first connection point and the second connection point of the power line.

5. The management device according to claim 4 , wherein

the first insulating circuit is a capacitor,

the second insulating circuit is a capacitor, and

the low-pass filter is an inductor.

6. The management device according to claim 4 , wherein

the first insulating circuit is a transformer,

the second insulating circuit is a transformer, and

the low-pass filter is an inductor.

7. A power supply system comprising:

a plurality of power storage modules each including a plurality of cells connected in series, and

the management device according to claim 1 .