纯电动客车氢镍动力电池包散热系统研究

Research on Ni-MH battery pack heat dissipation system of pure electric bus

氢镍动力电池包散热不良会影响电动汽车整车的使用性能,严重时还将导致安全事故,因此电池包散热系统性能至关重要。建立了三维非稳态氢镍动力电池包散热系统模型,应用计算流体力学(CFD)的方法,对采用不同进、出风口角度(θ)的氢镍动力电池包流场和温度场进行数值模拟。结果表明随θ角度的增大,动力电池包中最高温升和最大温差都会有所降低,并且θ角度较小时改变θ值对散热的影响最为明显,随着θ角度的逐渐增大,散热效果变得不再明显。在这基础上,分析了氢镍动力电池包散热不良的原因并提出了散热结构改进方案,最后经两次改进后,氢镍动力电池包散热系统仿真结果表明:电池包中的最高温升由50℃降为36℃,最大温差由26℃降为6℃,电池包散热明显改善。

The effect of non-uniform heat dissipation of Ni/MH battery pack will affect the vehicle performance, and will also lead to some serious safety issues. The structure design schemes on heat dissipation system were proposed for battery pack. A three-dimensional heat dissipation system model was built for Ni/MH battery pack. The CFD models of different inlet angles and outlet angles（θ angle） were used to simulate the flow field and temperature field of the Ni/MH battery packages. The results show that the highest temperature and the temperature difference of battery pack decrease with the increase of theta angle, and the heat dissipation effect by altering the value of theta is most obvious when theta angle is small,as the theta angle gradually increases, the cooling effect is not obvious. On this basis, a structure improvement scheme for the heat dissipation system of Ni/MH battery pack was proposed and the simulation was performed. The results indicate that after two improvements, the temperature rise of battery pack lowers from 50 ℃ to 36 ℃ and the temperature difference among the batteries lowers from 26 ℃ to 6 ℃, and cooling effect is good.