A battery management system is provided for managing a battery that supplies power to a vehicle. The battery includes a plurality of cells. The battery management system includes a sensing unit for measuring a voltage of each of the plurality of cells. The battery management system detects at least one first cell among the plurality of cells that needs to be balanced according to the measured voltage of each of the plurality of cells. In addition, the battery management system performs a cell balancing operation on said at least one first cell by using different methods according to a driving state of the vehicle.