Experimental investigation of thermal management system for lithium ion batteries module with coupling effect by heat sheets and phase change materials

Some potential safety risks for lithium ion battery such as overheating, combustion, and explosion occurred in practical application may cause accidents of electric vehicles. Phase change material (PCM)-based thermal management system was demonstrated as a feasible approach. However, the batteries have to endure various environment and climate, which would not work normally under cold area. Especially when the surrounding temperature falls to below 10 degrees C, which can bring about the energy and power of Li-ion batteries rapidly reducing. In this study, a coupling heating strategy of the PCM-based batteries module with 2 heat sheets at low temperature was proposed for batteries module and cannot only balance the temperature among different batteries in the module but also ensure to pre-heat the batteries module at low temperature. The experiment displayed that 7% of EG in paraffin-based composite PCMs was the best proportion for batteries module, considering both fluidity and thermal conductivity factors. In addition, the temperature difference of PCM-based batteries module was 2.82 degrees C, while that of the air-based one was 14.49 degrees C, which was 5 times more than former, exhibiting an excellent performance in balancing temperature uniformly, and was beneficial for prolonging the lifespan of batteries. The coupling heating strategy-based PCM with heat sheets provided as an extremely promising technology for lithium batteries module at low temperature.