Research into an Efficient Energy Equalizer for Lithium-Ion Battery Packs

An efficient multi-mode energy equalizer for lithium-ion battery packs is proposed and energy balance strategies are studied in this paper. The energy balance strategies include the selection of the controlled object in the battery's different working states and the current form of the controlled object. During the energy balancing process, the strongest single cell or the weakest single cell is selected as the controlled object according to the different working states of the battery, and the balanced current of the controlled object is continuous. Therefore, the energy equalizer proposed in this paper has a fast balancing speed, an improved balancing effect, and an excellent balancing reliability. According to the energy equalizer, the relevant experimental platform was built, and balance experiments in the battery's different working states using a battery pack composed of four serially-connected lithium iron phosphate batteries were completed. Finally, the experimental results proved the effectiveness of the energy equalizer.