| With more and more serious problem of environment coming and the need of development for low-carbon society, the electric vehicles have achieved leap-forward development under the great support of the country in recent years. The electric vehicles cannot make rapid development without constant update and progress of key technology, As the core power source of electric vehicles, especially pure electric vehicles, Power battery has become the focus of research. Thermal management system directly affects the safety, consistency and durability of battery, it is the important part of research. Therefore, it has very important practical significance to study the thermal management system of power battery.When the electric vehicle is running for a long time, the battery will generate a lot of heat, if the heat accumulated in the pack cannot be discharged in time, battery’s life will be reduced, much more serious, maybe it will make heat out of control, which can threat personal safety. In this paper, CFD method is used to analyze the temperature field of the power battery, and the performance of heat dissipation is evaluated by previous results.In this paper, the coefficient of thermal conductivity was firstly calculated according to the composition materials and structure features of battery, the heating curve is fitted by Bernard equation and experiment, then, the simulation of single battery is carried out, and temperature-rising tests are made when the battery is at 30℃, the feasibility of the simulation model and the accuracy of the numerical results are verified by comparing the results.Secondly, pure electric vehicle simulation model is built by advisor, dynamic characteristic of power battery is analyzed respectively under the NEDC and HWFET test conditions, the working range of the output current of battery in different working conditions are found out, which is laying a foundation for later heat dissipation analysis.Then, the numerical analysis is carried out after the simulation model of the battery pack is set up. velocity field and temperature field distribution in battery pack are obtained when battery is working at the discharge rate of 0.75C and 1C. At last, it is discussed that how the supply air velocity and air temperature affect the heat dissipation of battery pack.Finally, two improved structure are proposed aiming at the problem of local high temperature in the battery, both of that are increasing air flow velocity and flow rate at the corner of the pack, reducing the temperature of battery, raising the temperature uniformity, improving the heat dissipation performance. |
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