Dynamic Electrical-Thermal-Mass Response Characteristics of Alkaline Water Electrolysis System

The intermittent and fluctuating features of renewable sources present challenges for the efficient and secure operation of alkaline water electrolysis for hydrogen production. However, its dynamic response characteristics are still less investigated. Through the integration of dynamic experiments and simulations instead of the traditional steady-state analysis, the dynamic electrical-thermal-mass response characteristics of electrolyzer systems are evaluated at both the system and cell levels. The variation in cell voltage follows a pronounced monotonicity in spatial distribution under dynamic operation. Industrial electrolyzers exhibit prolonged cold-start durations (>1 h), dominated by thermal inertia rather than electrical or pressure dynamics. The spatially resolved simulation identifies cathode–anode exit temperature asymmetries (ΔT=1.5 K). The hydrogen to oxygen ratio and oxygen to hydrogen ratio show almost synchronously delayed and inertial responses, with lye mixing predominating total hydrogen crossover (74.1%±2.5% contribution). This work has proposed experimental basis and simulation tools to better understand and predict the dynamic performance of electrolyzer systems in favor of future optimization of electrolysis system design, renewable energy integration, and clustering operation.