Hierarchical platform for monitoring, managing and charge balancing of LiPo batteries

One of the key aspects which determines the performance of a Lithium battery pack used for traction on electric vehicles is how the charge is equally distributed among the cells. Indeed, charge balancing is one of the main function that a Battery Management System (BMS) has to perform. Even though the study of balancing systems is currently considered a hot topic, there are no common procedures and metrics to evaluate their performance. A three-level hierarchy BMS with test benching features was designed for this purpose and it is discussed in this article. It is able to provide valuable comparisons and information about the efficiency and the balancing time of different circuitries, when used together with an ad-hoc defined test procedure. Some experiments carried out on different passive and active balancing circuits are presented and discussed.