Suitability of different phase change materials for thermal management of Li-ion battery modules across diverse operating conditions: Experimental and numerical approach

Abstract

Efficient thermal management of lithium-ion (Li-ion) battery modules is crucial, specifically when using phase change materials (PCMs) based passive cooling strategies. Though PCMs have been widely explored, their thermal control ability depends on the type of PCM, operation under constant/cyclic load, ambient temperature, etc. This study evaluates the suitability of different PCMs for thermal management of a battery pack (18 V, 7.2 Ah) under diverse operating conditions through a combined experimental and numerical approach. The operating parameters studied are charge/discharge at various C-rates, constant & cyclic load profiles, PCM types, and ambient temperatures. The surface temperature and temperature non-uniformity of the battery module are monitored and compared under natural air convection, both without and with PCM cooling. The results showed that the use of PCM lowered the average battery pack temperature compared to air cooling, and achieved a reduction of 7 °C at 2 C discharging. Furthermore, the use of PCM improved the temperature non-uniformity of the battery module, limiting it to 4.5 °C during discharging at 2 C, which is 16.6 °C in natural convection. Under cyclic loading conditions, the use of PCM led to a significant temperature reduction of approximately 20 °C compared to natural convection. Moreover, numerical simulations reveal that Eicosane performs better at an ambient temperature of 30 °C, whereas 1-Hexadecanol is more effective at 40 °C. Additionally, results confirm that higher ambient temperatures adversely impact the battery surface temperature. The study provides critical insights into the effectiveness of PCM selection to cater to the thermal management needs of the Li-ion battery packs under variable operating conditions.