Design, Integration, and Multiphase Modeling of Phase Change Material (PCM) for Thermal Management of BEV Inverter

Sammanfattning

With the rapid advancement of electromobility sector, the power density and heat generation of electronic chips is significantly rising. Due to its higher load and lower thermal mass, electronics chips in BEV inverters, such as MOSFETs, are increasingly susceptible to rapid temperature rises. Through the utilization of latent heat absorption, Phase Change Material (PCM) offers a promising passive cooling solution for sudden temperature spikes, while eliminating the requirement of continuous coolant flow for BEV inverter cooling. This paper aims to evaluate the effect of PCM integration on thermal performance by investigating the effect of heat sink designs, PCM materials, PCM coverage strategies, and metal foam porosity on MOSFET temperature. Based on the results, Design 3 and Design 5 demonstrated the best performance in dissipating heat into the PCM domain due to their high effective mean thermal conductivity. However, the influence of porosity on thermal performance proved to be complex and highly dependent on the overall heat sink design. This trade-off is more noticeable in Design 3, where the thermal conductivity and latent heat capacity are properly balanced. Additionally, the choice of PCM material strongly influenced the timing and effectiveness of flattening temperature. Highmelting-point PCM tends to delay melting, while low-melting-point PCM often leads to premature melting. In this case, RT64HC offered the best balance in promoting thermal buffering effect. The PCM coverage strategy also affected thermal performance significantly. Partial coverage was ineffective due to insufficient PCM volume, while full x-axis coverage outperformed y-axis coverage by allowing more uniform and direct heat exposure. The two best configurations in this study were full y-axis with RT64HC at P0.2 and full x-axis with RT64HC at P0.3, where both configurations promoted flattening temperature during second acceleration cycle. However, the x-axis configuration is preferred for its greater potential for future improvement.