Research on portable balance devices and balancing strategy for batteries

Abstract

Consistency of batteries determines life and discharge period of battery Pack and many factors. As to difference in performance of batteries which have been used for a period of time, a balancing method based on SOC and voltage detection is proposed in this paper. On the aspect of balancing strategy, difference between instant voltage and SOC needs to be evaluated by referring a weight table to choose appropriate charging or discharging strategy in different situation. As for detection and control of hardware, a two-way DC-DC balancing circuit is established to balance power between packed batteries. Finally, a platform composed by 12 cell lithium-ion batteries is established to perform a charging and discharging experiment with 0.3 time of rated power. The effectiveness of balancing strategy is examined by comparing SOC results at end of the entire experiment in both situation with and without balancing strategy.