Dynamic modeling of alkaline water electrolysis cell with consideration of two-phase bubble transport for renewables dedicated operation

A one-dimensional dynamic model has been developed to analyze the dynamic characteristics of alkaline water electrolysis (AWE) in response to variable load changes. In the model, the control volume is discretized in a perpendicular direction according to the general zero-gap alkaline water electrolysis cell configuration. Dynamic conservation equations are applied to resolve the mass and energy balances. Each control volume is configured with individual and localized properties and is associated with adjacent control volumes to model the entire cell assembly. The model effectively simulates observed experimental data, especially the cell voltage dynamic response shape after changes to the current density. The validated model is used to investigate the influence of key physical factors on the dynamic cell voltage response. The results reveal that the time delay caused by temperature changes is considerably longer than that induced by gas saturation, which stabilizes much more rapidly after a load change. Based on the parametric study, an operating condition control strategy for realizing dynamic stability is presented. The dynamic model developed in this original study has been demonstrated to be a useful tool for investigating the effect of inlet conditions and load changes. Moreover, it can contribute to the development of control strategies for enhancing green hydrogen production performance with fluctuating power sources.