Employing extended surfaces for a hybrid battery thermal management system comprising PCM and refrigerated cooling air: An experimental investigation

If electric vehicles (EVs) are to supersede a larger share of the automobile market, developing safer battery packs with longer life and larger energy and power capacities is crucial. An effective battery thermal management system (BTMS) can promise many critical attributes of an EV battery pack, such as safety, life, and reliability. This article presents an effective BTMS with a novel hybrid design in which phase change material (PCM) is hybridized with a refrigerated air stream equipped with fins. The presented hybrid design is investigated experimentally and the role of fin structure and environmental conditions are examined. In addition, active and passive cooling strategies are also investigated to provide a more comprehensive analysis. The results show that the pure passive BTMS cannot control the module temperature in hot environments. On the other hand, although an active BTMS incorporating the refrigerated air provides a fast cooling process, the maximum temperature difference exceeds the improper value of 15 degrees C. The results demonstrate that the hybrid BTMSs can effectively control the temperature as well as minimize the maximum temperature difference. Furthermore, employing fins in the hybrid BTMSs leads to faster cooling. Among the three investigated fin structures, the spiral structure shows the best performance in controlling the average temperature of the module with a 4.2 degrees C temperature reduction relative to a similar case with no fin. The results of this study show that in long-term operation, a hybrid cooling strategy requires about one-third less energy in comparison to an active cooling strategy.