HEAT TRANSFER ANALYSIS FOR LI-ION BATTERY PACKAGE WITH A HYBRID THERMAL MANAGEMENT SYSTEM USING PHASE CHANGE MATERIAL AND FORCED CONVECTION

Battery charging and performance maintenance is one of the core technologies of electric vehicles. The performance of the battery is temperature-sensitive and the temperature should be kept within a certain range. Due to the nature of the car being driven and parked in the outdoors with extreme temperature changes, an efficient thermal management system is required. Cooling fans are mainly used for thermal management, but the power to drive the fans is used and the cooling capacity is limited. A method of using phase change materials has been proposed. The phase change material has a disadvantage in that the operating point is limited and heat transfer control is not easy. In this study, we propose a hybrid thermal management system with a cooling fan and a phase change material filled inside the battery pack. In order to investigate the cooling performance of the system, a series of CFD has been conducted for the hybrid cooling unit of the Li-ion battery pack in which the phase change and forced convection by implementing an immersed boundary method handling the conjugate heat transfer with a phase change. The simulation results show that the uniformity of the inter-cell temperature can be greatly improved when the phase-change material is filled.