电动汽车动力电池生热模型和散热特性

结合Bernardi生热速率模型建立了单体电池正极片集流体、负极片集流体和电池极板的热耦合模型以及成组电池传热模型；利用Fluent软件仿真分析了自然通风环境中LiFePO₄单体电池的生热特性，模拟了强制空气对流冷却条件下成组电池的生热和散热特性，分析了电池箱出风口位置对电池温度的影响；计算了不同放电倍率下电池组温度变化.计算结果表明：动力电池恒流放电末期，正、负极片的电流密度最大值出现在极耳处，正、负极耳温度高于极板温度，且正极耳温度大于负极耳温度；强制冷却条件下成组电池热特性满足安全工作温度要求；电池箱出风口位置直接影响冷却空气速度场和电池组温度场分布，出风口设置在电池箱下部有助于改善其热状态一致性.对特征点温度监控数据与仿真结果的误差小于5%，能够满足工程需要.

Heating generation model and heat dissipation performance of the power battery in electric vehicle

The thermal coupling models were established on the positive plate collector, the negative plate collector and the battery plate, which based on the Bernardi heat generation rate model of a single battery. The heat transfer model of battery group was founded as well. In the natural ventilation environment, the heat generation characteristics of a single battery LiFePO₄ was simulated by using Fluent software. The performances of heat generation and dissipation of battery group were simulated under the condition of forced air convection cooling. The effect of air-outlet position on battery temperature was analyzed. The effect on battery temperature was analyzed based on air-outlet position. In different discharge ratio, the battery temperature was calculated. The calculated results show that the pole ear temperature is higher than polar balde, and the postive ear temperature is greater than negative ear at the end of constant current discharging; The thermal performance of battery could meet the demands of the safe operating temperature in forced cooling conditions; The air-outlet position directly affests the air velocity profile and battery temperature field; The below air-outlet contributes to improve the consistency in thermal state. The error in calculating and testing result is less than 5% at the feature points, which could meet the needs in engineering.