BATTERY SYSTEM AND BATTERY MANAGEMENT DEVICE

A voltage measurer measures a voltage of a battery cell. A controller controls charging-discharging of the battery cell. The controller performs control to apply a reverse current for canceling a polarization voltage of the battery cell through the battery cell after the completion of charging-discharging of the battery cell. For example, after the charging-discharging of the battery cell completes, the controller sets a current command value, in a power converter, that instructs flow of a reverse current of a preset value for a preset time.