Cold-start performance investigation of fuel cell electric vehicles with heat pump-assisted thermal management systems

In this study, the cold-start performance of fuel cell (FC) electric vehicles was investigated via integration of a heat pump system with a thermal management system (TMS). A model for the proposed heat pump-assisted TMS and FC stack was developed using experimental data. On the basis of the validated model, the potential of the heat pump-assisted TMS was comprehensively evaluated from the standpoint of three critical factors: air velocity, compressor speed, and coolant volume flow rate (VFR). Consequently, it was observed that the cold-start performance can be maximized in the case of a large coolant VFR, high compressor speed, and air velocity above 0.96 m s⁻¹. Among the three variables, the most dominant was the coolant VFR, followed by the air velocity. When the compressor speed, air velocity, and coolant VFR were optimized, the cold-start time and total energy consumption of the heat pump-assisted TMS could be reduced by 29.9 and 11.3%, respectively, when compared to those of the baseline TMS during the cold-start period. In addition, an increase in the ambient temperature improved cold-start performance with the heat pump-assisted TMS.