Comparison of different thermal management strategies in tropical conditions for Li ion batteries and the effect of using Phase change materials (PCM)

The automobile sector is moving towards electrification as a replacement for the conventional IC Engine as the power source of vehicles. In electric vehicles, Li-ion battery is the widely used energy source for traction and is a major differentiator among various sub components that affect vehicle performance, safety and efficiency. The life of the battery pack is affected by different stress factors like SoC (state of charge), DoD (depth of discharge), C-rates (charge and discharge currents) and battery temperature. Out of the mentioned stress factors, the life of batteries is most influenced by the temperature excursion seen by the li-ion cells in the battery pack. There are various thermal management strategies available to keep the temperature under control like air cooling , chilled liquid cooling and hybrid cooling systems. The benefit of using Phase Change Materials (PCM) in case of hybrid cooling systems in mitigating thermal runaway propagation within the battery pack and the peak load temperature rise has been studied by several researchers. In this paper, an attempt has been made to compare the above mentioned three cooling solutions for the battery pack and also to understand the applicability of phase change materials (PCM ) for thermal management of Li-ion batteries in Indian tropical conditions. CFD and 1 D  commercial tools have been used to carry out this study under various scenarios such as normal operation, fast charging, and thermal runaway situation. In CFD, Heat generation in the cell has been calculated using the Equivalent Circuit Model. As part of this work a unique set of metrics have been decided to evaluate and compare the battery designs and cooling strategies. Detailed merits and demerits of each cooling system is discussed