CHARGE STATE EQUALIZING DEVICE AND ASSEMBLED BATTERY SYSTEM PROVIDED WITH SAME

A device that equalizes state of charge of each of a plurality of cells 1 connected in series which form an assembled battery includes a control circuit 20 and a discharge circuit 21 for discharging each cell 1. The control circuit 20 includes means that derives, for each cell to be discharged having a state of charge evaluation value different from an equalization target value, a discharge time or discharge end value with which the state of charge of a cell to be discharged becomes equal to that of a cell not to be discharged, based on the state of charge evaluation values of the cell to be discharged and the cell not to be discharged before the discharge by the discharge circuit 21 is started, a state of charge evaluation value changing speed during discharge of a cell, and a state of charge evaluation value changing speed during no discharge of a cell, and means that starts the discharge by the discharge circuit 21 for the cell to be discharged, and thereafter ends the discharge by the discharge circuit 21 for each cell to be discharged when the derived discharge time has elapsed or when the state of charge evaluation value reaches the derived discharge end value.