The effect of liquid channels and cold plates on the performance of hybrid thermal management strategies for cylindrical Li-ion cells

Abstract

In this paper, phase change material (PCM) based hybrid thermal management strategies are proposed for cylindrical Lithium-ion battery modules. Experimental and numerical studies are conducted to analyze the proposed strategies at a high discharge rate of 7 C. Three different types of thermal management configurations are developed. In all the configurations primary coolant is the PCM and secondary coolants are liquid and air. In one of the configuration vertical liquid coolant channels are placed between the PCM and airflow at the top of the cells. Whereas, in the two configurations different designs of cold plates are utilized in place of liquid channels. The experimental studies are conducted to obtain the temperature and heat flux profiles of the battery module. Moreover, a numerical model is developed and validated using the experimental data obtained. Using the numerical model, the thermal performance of the battery module was obtained for the proposed strategies. Based on the results, the maximum temperature of the battery module was limited to 29.1 °C and a high temperature uniformity was achieved by the end of the discharge cycle with the temperature difference limited to 1.2 °C. Additionally, the proposed hybrid thermal management strategy was capable of maintaining the required optimal thermal operating conditions without changing the phase of the PCM. Furthermore, it eliminates the requirement of a pump and reservoir since there is no flow of liquid within the battery module. This reduces the energy required for the operation of the thermal management system, thereby increasing the available energy for propulsion. Additionally, the developed strategy also increases the safety of the battery modules as it is capable of maintaining the required thermal environment in high discharge rates up to 7 C.