Thermal Management of the Li-Ion Battery Pack with Phase Change Material (PCM)

In electric vehicles, Li-ion battery pack is the most expensive subsystem. Therefore, extending the life of the battery pack and thereby reducing the need for battery pack replacement is necessary to offer a viable product at a competitive cost of ownership. Thermal management of battery pack plays an important role in achieving the above mentioned objective since the performance and life of lithium ion batteries is greatly influenced by temperature. There are various thermal management strategies available to keep the temperature under control like air cooling, chilled liquid cooling and hybrid cooling systems. In this paper, a comparison between phase change material (PCM) and PCM/liquid hybrid cooling is made. The result of the study to understand the applicability of PCM for thermal management of Li-ion batteries is presented. CFD thermal analysis under constant electrical load of 1C rate is carried out. Heat generation in the cell is calculated using the equivalent circuit model (ECM). As part of this work, a unique set of metrics were used to evaluate and compare the battery designs and cooling strategies. Detailed merits and demerits of the different cooling strategies are presented.