Automatic Cell Balancing with Switched Capacitor for Multi Cell Connectivity

Large number of lithium-ion cells are connected serially to gain high output voltage in electric vehicles. The adjacent cell-to-cell balancing method has slow speed and is less efficient in such multi-cell series-connected battery string. Automatic cell balancing using switched capacitor for multi-cell connectivity for 16 cells is presented in this paper. Balancing speed of the proposed switched capacitor equalizer does not rely on the number of battery cells and initial mismatch distribution of cell voltages. To provide a simple and flexible design for large amount of series connected battery cells, modularized architecture is proposed. MATLAB/Simulink model are developed for 4, 8 and 16 cells respectively. Simulation results are presented for to verify the feasibility of the proposed cell balancing technique.