A cell balancing battery module comprising: a cell string having N ports in series; a maximum and minimum finding circuit coupled with the N ports and the at least one switched capacitor comparison circuit for performing a voltage comparison procedure to find a highest voltage port number and a lowest voltage port number, the voltage comparison procedure including a plurality of voltage comparison operations using two phases of at least one switched capacitor comparison circuit; a charge and discharge connecting circuit coupled with the N ports and an inductor, and being configured to select a highest voltage port out of the N ports according to the highest voltage port number to deliver energy to the inductor, and select a lowest voltage port out of the N ports according to the lowest voltage port number to receive energy released from the inductor.