VOLTAGE MEASUREMENT DEVICE

A cell stack management system (1) includes a cell monitoring unit (10) that measures an output voltage of a plurality of power storage cells (81), a battery management unit (20) that manages a cell stack (8), and a first communication network (NW1) that connects the cell monitoring unit (10) and the battery management unit (20). The battery management unit (20) includes: a first communication circuit (21) connected to the first communication network (NW1); a second communication circuit (22) connected to a second communication network (NW2) for connecting to a higher-level system (2); a control circuit (23) that controls the battery management unit (20); and a control circuit power supply (33). The cell stack management system (1) includes a normal mode and a low-power mode as modes of operation. During transition from the low-power mode to the normal mode, the first communication circuit (21) activates at least one of the control circuit power supply (33), the control circuit (23), or the second communication circuit (22).