Experimental and Numerical Analysis of a Hybrid Thermal Management Concept at Different Discharge Rates for a Cylindrical Li-Ion Battery Module

Abstract

In this paper, an experimental and numerical study was conducted to analyze the performance of a hybrid thermal management concept for cylindrical lithium-ion battery modules at various discharge rates. The proposed concept consists of primary cooling through phase change material (PCM) and secondary cooling through vertical liquid channels between the PCM and airflow at the top of the cells. Two experimental studies were performed to obtain the temperature and heat flux profiles. In addition, the thermal performance of the battery module was obtained for 1 C, 2 C, 3 C, 5 C, and 7 C discharge rates using the numerical study. The results show that the maximum temperature was limited to ~30 °C. Additionally, the temperature uniformity in all the discharge rates was maintained below 5 °C. Finally, a meager amount of PCM was utilized during all the discharge cycles. At 1 C none of the PCM changed its phase, whereas at 2 C, 0.32%, 3 C, 0.14%, 5 C, 0.3%, and at 7 C, 0.12% of PCM changed its phase. The proposed hybrid concept can maintain the thermal environment required by the Li-ion cells for effective performance. Furthermore, this concept does not require excessive pumping fluid power and high air velocities, which reduces the energy required for the operation of the thermal management system, thereby increasing the available energy for propulsion.

Keywords

• phase change material
• hybrid cooling
• liquid channels
• battery thermal management
• computational fluid dynamics (CFD)
• Li-ion cylindrical cells