Research And Design Of Battery Management System For Electric Vehicle

Electric vehicle(EV) technology development has been progressing at a great pace around the world. As a representative of the new energy vehicle, electric vehicle has been widely used. Compared with other kinds of batteries, Lithium-ion batteries have prominent advantage, such as high capacity, high level voltage, high specific power, long serving life, low self-discharging, environmental-friendly and so on. More and more EV producer choose Lithium-ion batteries as the power battery. Restricted by current technology, EV with Lithium-ion batteries perform not as well as traditional fuel vehicle in terms of dynamic performance. Working performance of Lithium-ion is closely related to and contingent upon surrounding temperature. When the battery works in high temperature, it might be in danger of catching fire; when in low temperature, its capacity will decline, leading to the shortage of vehicle driving distance. Therefore, the development of a battery thermal management system(BTMS) is crucial.In the process of charging and discharging, the battery generates lot of heat. If the battery pack can`t disseminate the heat uniformly and rapidly, the temperature among the batteries will vary according to the location. Suitable ambient temperature is the necessary condition for the well functioning of batteries. This paper research the BTMS for EV, and then proposes an effective cooling system for battery pack. The specific research work includes:This paper refers to a large number of literature relevant to electric vehicles, power battery and battery thermal management system. Frist we discuss the component, working principle and thermal behavior of Lithium-ion battery; then we get the thermal and physical parameters of single battery according to suggested theory calculation. This paper builds the model of battery and compares the results with simulation experiments. On the basis of the model, this paper discusses the influence of discharge rate and ambient temperature on the battery temperature based on simulation experiment.With the assistance of ANSYS Fluent, this paper simulates the result of the temperature of battery pack. After the verification of the accuracy of the battery pack model, this paper designs several kinds of structure of fluid channel. The result indicates that the battery thermal management system using air medium performs significantly worse than using liquid medium. And different structure of inlet and outlet will affect the effect of cooling ability of battery pack. Given the same amount of input, a diagonal route of heat dissemination proves to possess much better cooling effect, with a maximum range of 5℃, producing generally satisfactory cooling results.Building upon this, the paper presents and compares the component of the cooling system in detail, including the bottom half, the frame, and presents the 3D models of these parts. It provides insight to the research and design of BTMS.