基于液冷的锂离子电池组热均衡性研究

In order to improve the thermal equilibrium of automotive Lithium battery module at high temperature and high rate, according to the heat transfer characteristics of the cylindrical Lithium battery, a three-dimensional thermal model of the 18650 Lithium battery cell was established, and the thermal characteristics simulation was carried out under natural convection at 40 °C. Finally, the reliability of heat generation model was verified in a temperature rise test. On this basis, a jacketed battery module cooling system was proposed for the power battery pack of a certain type of pure electric vehicle. Fluent software was used to study the influence of coolant flow, coolant temperature and discharge ratio on the heat dissipation equilibrium of battery pack at 40 ℃. The results show that increasing the coolant flow rate can effectively reduce the maximum temperature and temperature difference of the battery pack and the temperature difference of the battery itself, and improve the temperature uniformity between single cells. But when the inlet flow is increased up to 0.03 kg/s, the improvement effect is very limited. When the coolant temperature is reduced, the maximum temperature of the battery pack decreases, but the maximum temperature difference of the whole battery pack and the temperature difference between individual batteries rise continuously, and the maximum temperature difference between the single cells decreases slightly. When the discharge rate increases, the maximum temperature and the maximum temperature difference of the battery pack continue to rise, the temperature difference between the single cells and the temperature difference of the battery itself increases significantly, and the thermal balance of the battery pack becomes worse.