Adaptive Battery Equalization Algorithm for Capacitor-based Battery Management System

Abstract

In recent years, as energy-saving and environmental protection were widely concerned around the world, the lithium iron phosphate (LFP) battery has been widely used in hybrid electric vehicle (HEV) and electric vehicle (EV). Generally the battery pack for HEV is composition of the number of cells in series. In this case, imbalance among cells due to the difference of degradation and temperature will be accelerated by the cycles of charge and discharge without an appropriate battery equalization management system. However, the balancing system only intended to reduce the difference of cell voltage or Stage of Charge (SoC) before. "Adaptive Battery Equalization Algorithm for Capacitor-based Battery Management System" this thesis proposed re-explains the meaning of battery equalization. Instead of long-term using battery equalizer on standby, this thesis equalizes the battery when charging to save much spending time. It could not only adjust the balancing mechanism automatically in order to keep the available charge but also raise the average SoC to prevent the effect of battery aging and improve the cycle number of battery. Experiment results indicate that the available charge increases 1.5% and the battery capacity efficiently improves 7.3%.