Research Of The Battery Management System For EV

With the global economic development and the energy, environmental protection and other issues become more prominent, Electric Vehicles with zero emissions and low noise advantages of energy saving green vehicles has become the most important development directions, and more and more world attention, the rapid development in the twenty-first century. But the power source for electric vehicles-Power lithium-ion battery is the bottleneck of the development of electric vehicles. As the development of electric vehicles as one of the key technologies of the battery management system (BMS) is the key to solve the problem, more attention is the key to the industrialization of electric vehicles.Battery management system monitors and management of electric vehicle battery power to run the entire process, including the battery of basic information (including voltage, current, temperature and power) monitoring, estimated the remaining capacity, charge and discharge balance between single batteries, battery fault diagnosis and so on.In this paper, Chang He Ideal car modified for the test platform for electric vehicles, lithium-ion battery for the study, developed the battery management system for electric vehicle. Purpose of real-time monitoring of lithium-ion battery, extended the battery's life, increase energy efficiency and battery reliability.First analyzes the operating characteristics of lithium-ion battery remaining capacity factors and impact, compared the estimated battery state of charge (SOC) of several methods, and introduced the SOC estimation method used in this paper, which is ampere hour method and open circuit voltage combined.Secondly, for the characteristics of lithium-ion battery, designed the battery protection system based on Micro Controller Unit. Could be achieved single cell voltage monitoring to prevent the cells appeared in the use of charge, over discharge and so on; Monitoring the battery current and temperature signals, to prevent battery over current, over temperature, short circuit to reduce the battery life phenomenon. The management system based on Micro Controller Unit to achieve collected the battery voltage, current and accurate temperature, using the serial and Controller Area Network interface to complete communication links between the management system and other systems.Finally, building the experimental platform on electric vehicle, and connected the lithium-ion batteries and battery management system and associated debugging, testing, measured data and conducted data analysis. The results showed that:The battery management system's hardware was designed and implemented by paper reliability, economy and anti-interference ability. Can be achieved:Acquisition of the battery pack voltage, current, temperature'analog; balanced charge and discharge; calculate remaining battery time and judge the state of the battery; real-time display battery information and failure alarm functions.