Thermal Management Optimization for a Wireless Charging System of Electric Vehicle with Phase Change Materials

Abstract

The high-power wireless charging system for the electric vehicle (EV) generates irreversible magnetic loss and quantities of heat during the charging process. Using thermal management with phase change material (PCM) can reduce the temperature rising rate and ensure the operation safety. A thermal management optimization for a 6.6 kW wireless EV charging system with PCMs was studied. The mathematical model of the heat transfer process in the charging system with thermal management was developed. It was solved by a MATLAB procedure and verified by an experimental measurement. A concept of effective time was proposed as the optimization index to evaluate the performance of the thermal management system. The results indicated that the thermal conductivity of the PCM needed to be improved for a better thermal performance. The modified PCM as paraffin with expanded graphite (EG) was adopted and the optimum thickness and thermal properties were obtained. The effective time by using the optimal PCM layer was 3 and 1.2 times that by using the original PCM layer for the charging system with 5% and 10% energy loss, respectively. The optimal layer can keep the temperature of the charging system below 60 °C in long-term operation.