Heat pipe/phase change material passive thermal management of power battery packs under different driving modes

In Fluent's study of battery thermal dissipation in real driving mode. A passive battery thermal management (BTM) strategy based on heat pipe/phase change material (HP/PCM) coupling is proposed. The effects of different PCMs (including RT-31 and Paraffine-EG), HP, coupling systems, and different driving conditions (including constant speed, hill climbing, and dynamic driving) on the thermal behavior of the battery module are investigated. The results showed that: (1) the two coupling systems, HP/RT-31 and HP/Paraffin-EG, have lower battery surface temperatures and better overall temperature uniformity compared to the no HP/PCM, HP alone, and PCM alone. Battery maximum temperatures were reduced by more than 10 % compared to no HP/PCM. The temperature reductions were 1.48 K and 0.67 K compared to HP only, and 3.1 K and 3.4 K compared to RT-31 only and Paraffin-EG only, respectively. Where HP dominated the reduction of the maximum temperature, and PCM played a key role in maintaining temperature uniformity. (2) Under different uniform driving conditions, the coupling system exhibits more significant temperature reduction at higher speeds, with a maximum temperature reduction of 13.9 % at 120 km/h driving. (3) Uphill driving in high temps lowers resistance, boosts electrochemical activity, slows temp rise, and reduces temperature difference. The passive thermal management system designed in this paper, not only makes the battery temperature rise effectively but also has important significance in improving energy utilization and reducing the additional energy consumption of power batteries.