Advances in HEV Battery Management Systems

A critical element of a hybrid-electric-vehicle (HEV) propulsion system is the battery management system (BMS), which controls the performance of the HEV battery, the costliest and heaviest component of the propulsion system. This paper examines the relevance and criticality of an HEV BMS as a whole; that is, its general functions and “responsibilities”. Of these, its ability to accurately estimate and report the state-of-charge (SOC) is arguably the most important. This paper will explain why SOC estimation is important, and will examine advances in the state of the art of SOC estimation methods, with a focus on Kalman Filter techniques.