Voltage equalization for series connected lithium-ion battery cells

Battery powered electric vehicle technologies are advancing in the present world for minimizing the global warming effects. The electric vehicle concept comes as alternate to internal combustion engine vehicles that uses electric energy from electric energy storage systems of high-energy capacity and long-life cycle. Lithium-ion (Li-Ion) batteries are utilized as energy storage in most of the electric vehicles as its high energy density, long life cycle etc. However, Li-Ion battery needs the maintenance for safety operation and long lasting. As protection, series connected battery cells monitoring and equalizing are mandatory. The individual cell monitoring and active balancing techniques are highly efficient as battery management system (BMS). In this paper, an equalization technique is proposed that exposes the individual cell monitoring and fast balancing of cell voltages. The balancing circuit with this equalization technique is modeled in MATLAB/Simulink and the balancing outputs are produced with series connected 8 Li-Ion battery cells.