There are provided a battery control system and a battery control method which can eliminate a management device controlling voltages of individual cells in a battery pack, resist the influence of noise, prevent an increase in size, and reduce the load on a management device. A cell for a battery pack will be interconnected with another cell to be used as a battery pack, the cell comprises unit cell 5 and control circuit 1, unit cell 5 is one electrochemical cell, and control circuit 1 includes: measurement means 1 a for acquiring cell-state information including at least a voltage of unit cell 5; transmission means 1f for transmitting the cell-state information to the outside; reception means 1f for receiving external information; and means 1d for discharging unit cell 5 based upon the cell-state information on unit cell 5 and the external information, to bring the voltages of interconnected cells closer.