Research Of The Battery Energy Management System For Hybrid Vehicle

Under the pressure of environment pollution and the scarcity of oil source, to be dedicated to the strategy of sustainable development, Hybrid Electric Vehicle (HEV) becomes an important consideration in the twenty-first century in order to get sustainable development of Automobile industry. All specialist in whole world have agreed on this: the application of Hybrid Electric Vehicle will not be a transition phase, but be a new revolution of Automobile industry. Because the service life of NiMH battery is limited and the running circumstances of HEV are considerably complex, which influences the service life of NiMH battery, it is very essential to realize to efficiently manage energy of NiMH battery. But the Battery Management System (BSM) of HEV is very expensive and its circuit is complex, simultaneously, chemical changes are also complex during discharging and charging of NiMH battery, so it is extraordinarily difficult to calculate and estimate an accurate surplus energy and State of Charge of NiMH batteries. Up to now, this technology is still researching and developing.Based on the experiment of NiMH battery, investigations on characteristics of discharging and charging of NiMH battery, and analysis of influencing factor of NiMH battery, an approach of Ah—COE—OCU has been carried out to estimate an accurate surplus energy and State of Charge of NiMH batteries, and consider the compensation of the temperature, aging and self-discharging etc. After theoretic analysis has been completed, simulations are given to determine parameters of batteries for Changan HEV.On the basis of the experiment of NiMH battery, theoretic analysis and parameters determined, simulation of NiMH battery discharging has been carried, and simulation results are identical with the practice. Then, the impulse phases quick charging has been applied to process the simulation of quick charging of NiMH battery based on mechanism analysis and theoretic comparison about quick charging of NiMH battery. Simulation results are satisfactory.At last, researches and designs of the Battery Management System (BSM) of HEV battery are introduced. This system can not only check-up performance (such as thecurrent of discharging and charging, voltage and temperature) of every battery, and have functions of giving an alarm and trouble diagnosing early to prevent excessive discharging and charging of the battery, but also provide a direct display of surplus energy and state of charge of NiMH battery of HEV.