Study On The Charging And Discharging Characteristics Of Power Battery Pack Used In Electric Vehicle

The problems of energy, environment and economic are always had the attention by people. Electric vehicle as a kind of traffic tools is energy saving, environmental friendly and has become the research focus in automotive field. However, the problems of driving mileage short, expensive existed in the electric vehicle make it difficult to widely used. The key to the questions is to improve the technology of power battery, to enhance its performance and low price. It is finished that the simulation research about the charging and discharging characteristics of the power battery pack used in EV. This provides theoretical basis for the development of the power battery technology.There are many kinds of power battery type and in this paper lead acid battery and lithium ion batteries are study objects. First the work principle of the two batteries and fast charging principle are elaborated. Power battery recharging circuit is introduced and the simulation model of charging power that is formed by the high frequency switching power was built. Finally, the third-order model of the lead acid battery and the nonlinear battery model of lithium ion battery are used in the simulation research. The charging and discharging characteristics for the large capacity monomer battery are studied. The charging characteristics of lithium ion battery under the fast charging methods and the charging and discharging characteristics, temperature characteristics of lead acid battery with the driving process of fuel cell electric vehicle are researched.The main research results are as follows. ZVS phase shifting full bridge converter as a DC-DC converter is employed in high frequency switching power, which with the control strategy of equal loss for switch tube. Five-stage constant current fast charge method is put forward based on fast charging principle. The charging current of the fast charge method are determined using consecutive orthogonal arrays. The simulation results using the five order constant current fast charging method show that is a kind of high efficient and practical charging methods. Third-order model of lead acid battery is applied in fuel cell electric vehicle successfully which has important significance to improve battery management system and electric car energy management system.