电动汽车用高导热车载线温度场分布与载流量分析

Analysis on Ampacity and Temperature Distribution of Electric Vehicle Cable with High Thermal Conductivity

为了扩大新能源汽车市场,提升新能源汽车动力传输的效率,需要提高其内部车载线的载流能力,但同时随着负载电流的增加,车载线的散热困难问题凸显。本研究应用COMSOL软件建立车载线电热耦合的有限元仿真模型,应用Nelder-Mead方法求解出载流量,并对比解析方法,验证Nelder-Mead方法的有效性。仿真分析绝缘材料热导率的提升对车载线载流量和散热的改善效果。结果表明:应用热导率为0.833 W/(m·K)的硅橡胶/氮化硼纳米片(20%)高导热复合材料,仿真得到车载线的载流量提升了5.12%,在过载时能更好地促进散热,但也增加了绝缘临界半径,导致绝缘厚度在绝缘临界半径以内减薄时,导体温度有轻微升高。

In order to expand the new energy vehicle market and improve the power transmission efficiency of new energy vehicles,it is necessary to improve the current-carrying capacity of its internal cables.But at the same time,with the increase of load current,the heat dissipation problem of vehicle cable has become prominent.In this study,a finite element simulation model of vehicle cable considering electric field and thermal field was established by COMSOL software,the ampacity was solved by the Nelder-Mead method,and then the effectiveness of Nelder-Mead method was verified by the analytical methods.The improvement effect of the increase of insulation material thermal conductivity on the current-carrying capacity and heat dissipation of the vehicle cable was simulated analyzed.The results show that when a silicone rubber/boron nitride nanosheets(20%)composites with 0.833 W/(m·K)of thermal conductivity was used in vehicle cable,the ampacity of vehicle cable obtained by simulation increases by 5.12%,which can promote heat dissipation more significantly at overload,but it would increase the critical radius of insulation,resulting in a slight increase of conductor temperature when the insulation thickness decreases within the critical radius of insulation.