Analysis Of Cell Balancing Techniques In BMS For Electric Vehicle

This paper explains how the Battery Management System (BMS) in an Electric Vehicle uses cell balancing techniques to balance the li-ion cells in lithium-ion battery pack. Cell balancing is done to ensure that all li-ion cells in a battery pack are charged and drained together. There are two types of cells balancing techniques: Passive cell balancing and active cell balancing. Passive cell balancing is accomplished by discharging the excess charge to a bleeding resistor but active cell balancing is accomplished by transferring the charge from higher charged cell to lower charged cell. Moreover, the charge is squandered in passive cell balancing, therefore in this technique cell balancing efficiency is harmed. However, when it comes to active cell balancing, charge transfer is accomplished via a transformer, inductor and capacitor so this balancing technique gives high efficiency compared to passive one. The simulation results of all methods of cell balancing are presented in this paper.