Research And Implementation Of The New Type Lithium Lon Battery Management System In EV

The importance of electric vehicle (EV) is emphasized in the world due to the enhancement of environmentalism and the pressure of energy storage. The main restriction of the EV development is the storage battery and its application technology. How to prolong the life cycle of the battery, enhance its reliability and efficiency are the key problems to EV industry. So the study of battery management system (BMS) becomes more and more important.The battery management system performs many functions, including inspecting the whole process when it's running, cell equalization, protecting and diagnosing the battery, estimating the state of charge (SOC). On the basis of the battery management system developed by different countries, we improve on the design idea and the architecture of battery management system, for example, using CAN field-bus, cell equalization module, 1-wire bus, a new estimate algorithm of the state of charge and fuzzy diagnostic expert system. The system is proved to be practical by experiments.At the beginning, this paper describes the total design of the distributed battery management system. Then the function modules of each node are introduced with emphases on the improvement such as the new measure methods of the voltage of the battery, CAN field-bus with 14 nodes, cell equalization methods, the fuzzy diagnostic expert system and the new estimate algorithm of the state of charge which synchronously taking into account the factors affecting it.Lastly, the paper introduces the problem happened in the system debugging and resolution, analyses the experiment result.