Flexible Fuel Cell System Design for Electric Bus: Durability Enhancement and Fuel Economy Improvement

This article proposes an optimal design approach for the multiple fuel cell stack system (MFCS) used in electric vehicles. The MFCS has the flexibility to determine the operating fuel cell stacks depending on the power requirement, resulting in improvements in durability and fuel economy. To explore the potential of the MFCS, we first model the dynamics of the fuel cell electric vehicle (FCEV). Then, a two-stage optimization framework incorporating dynamic programming (DP) with the genetic algorithm (GA) is proposed. DP is employed to generate the global energy management strategy (EMS) for each candidate solution, while GA is utilized to ensure the even usage of fuel cell stacks. By employing the two-stage optimization framework, the optimal stack numbers, and component sizes for a practical application are obtained with the minimum hourly cost. The results indicate that the MFCS achieves its optimal performance with a stack number of 3, leading to a remarkable increase in its lifetime by 16.60% compared to the single fuel cell system. In addition, the component sizing yields even greater durability, showcasing a remarkable 34.97% improvement in a lifetime when compared to the original design.