A Study of Energy Loss in LiFePO4 Battery-Balancing Schemes for Electric Vehicle Applications

High energy density LiFePO4 battery plays an important role in the EV application. Due to strictly charging requirement, battery balancing is a necessary function in a battery management system (BMS) for charging this type of battery. Normally, there are two types of battery balancing circuit, i.e. active and passive balancing circuit. Because of simplicity, a passive circuit is chosen. Technically, passive balancing has energy loss while batteries are balancing. This research is focused on exploring three kinds of passive-balancing schemes about energy loss and at various conditions e.g. considering at balancing current or state of charge among all cells (SOCmax - SOCmin). The simulation results show that the different balancing schemes do not have significant effect on energy loss.