Evolution of Characteristic Parameters in Fuel Cell Dynamic Response Under Durability Testing

The evolution of two key dynamic response parameters—undershoot voltage and stabilization time—was investigated throughout a 1000-h durability test on four distinct PEMFCs. Results demonstrate that cells with superior mass transport exhibited higher undershoot voltages, an effect amplified at higher current densities due to a more pronounced gas supply-demand imbalance. Notably, the undershoot voltage decreased during the initial cell activation phase. Conversely, stabilization time showed no clear correlation with load magnitude but increased systematically with performance degradation. These findings reveal a strong connection between dynamic response characteristics and performance decay, providing meaningful insights for the design, application, and health assessment of high-performance fuel cells.