Experimental and Numerical Investigations of a Thermal Management System Using Phase-Change Materials and Forced-Air Cooling for High-Power Li-Ion Battery Packs

Abstract

The thermal management system of a power battery is crucial to the safety of battery operation; however, for the phase-change material (PCM) thermal management system of a battery, the thermal cycling of phase-change material under large discharge rate conditions will lead to thermal conductivity degradation and thermal stress problems. A method of manufacturing PCM containers with metal fins to package pure phase-change material is put forward to solve the problem. The system temperature under different conditions is studied using numerical and experimental methods. A thermal resistance model is built to analyze the thermal transfer performance of PCM containers with fins. The results show that the PCM container structure can effectively control the battery temperature within the suitable temperature range under the low discharge rate, but the maximum temperature of the battery pack at the high discharge rate of 3 C will exceed the optimum operating temperature range. Adding fins can reduce the maximum temperature and improve the system temperature uniformity. By combining fins with forced-air cooling, the maximum temperature and maximum temperature difference of the battery pack at a high discharge rate can be effectively reduced.

Keywords

• thermal management
• Li-ion batteries
• high-rate discharge
• phase-change material
• PCM container structure
• forced-air cooling