Review of Present Status and Recent Development in Active Cell Balancing Technique

Electric Vehicles (EVs) prove to be a sustainable mode of transportation concerning environment friendliness and the limited reserve of petrol and diesel. Notably, a crucial constituent of an EV is the battery. So, it becomes significant to safeguard the battery and prolong its operational life. Battery Management Systems (BMS) is a smart technique employed in EVs that manages and controls the charging and discharging operations of batteries. Cell Balancing (CB) is an imperative function of the BMS that maximizes battery efficiency by balancing the State Of Charge (SOC) levels and consequently the voltages of the cells in a battery pack. CB phenomenon is broadly classified into the Passive Cell Balancing (PCB) and Active Cell Balancing (ACB) strategies. PCB strategy involves the expulsion of charge from higher SOC cells to the connected dissipative resistors for balancing its SOC as per the lower SOC cells. This technique is usually preferred for low-power applications involving low cost. However, for high-power applications, it necessitates the use of the ACB strategy where charge from higher SOC cells is disseminated among the lower SOC cells so that the SOC of all the cells balances to an average SOC value. As a result, the battery run time can be augmented and that would extend the driving range of an EV. This work focuses on reviewing the different ACB strategies of BMS that can be successfully used for EV s.