Steady-State Characteristic Assessment and Dynamic Performance Testing for a Metal-Supported Solid Oxide Fuel Cell Auxiliary Power Unit with Methanol On-Board Reforming

The highly efficient and low-pollution solid oxide fuel cell (SOFC) power generation system offers a clean energy supply solution, playing a significant role in promoting energy transformation and accelerating the development of low-carbon energy. Safe and portable liquid fuels have received extensive attention in mobile SOFC applications due to their excellent fuel versatility. However, the overall performance of the SOFC system is highly dependent on reforming options and operating strategies. In this study, a novel methanol-reforming on-board SOFC auxiliary power unit (APU) system is proposed. The performance of SOFC with methanol under steam and autothermal reforming is evaluated by thermodynamic analysis at 550 °C with 0.3 A/cm² current density for a metal-supported SOFC stack. The methanol autothermal reforming (ATR) consumes less heat and shows better start-up performance compared with steam reforming, making it more suitable for the SOFC-APU system. The maximum electrical efficiency of the SOFC system can reach 47.5% with methanol ATR. By optimizing the reforming strategy and operating parameters, the conceptual design of the SOFC-APU system achieves a balance between system efficiency and methanol consumption during the steady operation phase. The simulation results showed that the electrical efficiency of the system reached 52.1% with a 0.46 g/s methanol flow rate at a 70% anode gas recirculation ratio. Based on the above SOFC-APU system, a dynamic series hybrid system with a battery as the main driving power source and an SOFC as an auxiliary power source was designed and simulated. The hybrid system can meet the dynamic and economic requirements, making up for the short mileage and endurance of the electric vehicle. Meanwhile, it reduces the peak power demand of the battery system and prolongs the battery life, showing the development potential of an SOFC in the future transportation field.