Battery management systems in the China-made “Start” series FCHVs

In the China-made ldquoStartrdquo series fuel cell hybrid vehicles (FCHVs), the power battery pack, which contains a series of Lithium-ion batteries, plays an important role in the dynamic system. For developing the vehicles with high performance and good reliability, the batteries have to be managed to obtain maximum performance under various operating conditions. In this paper, a battery management system (BMS) was introduced which was designed for optimizing the use of the batteries. This system was a level-based system which contains a high-level system called ldquoCentral ECUrdquo (CECU) and several low-level systems called ldquoLocal ECUrdquo (LECU). The software of the battery management system was designed based on the UC/OS-II to guarantee the real-time requirement. The system performs such several tasks including states monitoring (State of Charge, SOC and State of Health, SOH), creepage detection, cell balance, thermal management, power limitation, diagnostics etc. In the two experiments shown in the paper, results indicate that this BMS performs well in managing the power batteries used in ldquoStartrdquo series FCHVs, it could estimate the states of the battery accurately, detect the creepage and do some protect in real time, balance the cell very well and maintain the temperature of the battery pack in a satisfactory manner. Other critical functions have also been tested during the vehiclepsilas on-road testing.