Modelling And Simulation Study Of Battery System Of Electric Vehicle

With the emergence of energy crisis and environmental pollution, the low-emission and energy-conservation car relying mainly on electric vehicle (EV) has been paid attention to and developed. In the earlier period of electric vehicle development, the modelling and simulation with computer has the vital role. As the energy storage system of EV, the battery performance is the important attribute of deciding the entire vehicle performance, and the battery is the integrated system of electricity, chemistry, the thermodynamics, the dynamic characteristic exceptionally complex, therefore the battery modelling and simulation really is the important link and difficult partial of the electric vehicle modelling and simulation. In the practice of scientific research item, the author applies the theory of bond graph to the modeling of the battery of EV after further researching, and has received the very good effect, also opens up the new train of thought of the battery modelling and simulation.The author briefly introduces the present situation of modelling and simulation of the battery and its temperature management system on EV. And discusses the rationale of bond graph and its application in engineering emphasis on the use in the electricity system and the thermodynamic system in detail, and obtains the state equation at last. The means of battery modelling is discussed and the method of equivalent circuit is applicable, and the reference model is adopted because of its higher precision and more reasonable after comparing the several kinds of commonly used equivalent circuits, moreover the bond graph model of the equivalent circuit of reference model is established. Also the thermodynamics condition and energy flow of the parallel-flow air cooling mode that is one of the modes of battery's temperature management system is studied, and the bond graph model of the temperature management system is built. The bond graph model of the battery system is obtained by coupling the bond graph model of the equivalent circuit and the bond graph model of the temperature management system. Furthermore the mathematical model of the battery system is deduced. The more reasonable algorithm of SOC is applied after discussing the influence factor the definition of SOC and comparing and analyzing several commonlyused calculating method. Using the MATLAB/SIMULINK simulation software, the simulation model of the battery system is established. The dynamic simulation of a kind of Ni-Zn battery is realized, and the results are very good comparison with the experimental result. Also the vehicle simulation is realized. Based on the above work, the author has established a set of perfect modelling and simulation system of the battery on EV, and it provides the reliable basis for the simulation of vehicle and the control strategy. The model suits to all liquids electro-chemical battery. Author's work has carried on the effective attempt for study and simulating the complex dynamic characteristic of battery, opened up the new train of thought and made the contribution for the development of bond graph theory.