Experimental Validation and Semi-Empirical 0-D Modelling of Pressure Effects in AEM Electrolysers

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Abstract
Anion Exchange Membrane (AEM) water electrolysis is emerging as a costeffective technology. Currently, the modeling of pressurized AEM stacks remains limited for fast system-level simulations. This work presents a semi-empirical zero dimensional (0D) model accounting for pressure effects in AEM electrolyzers and validates it against an experimental campaign on a 2.4 kW stack operating at 10-30 bar, 30-50 • C, and current densities up to 0.48 A/cm 2. Experimental results show that increasing hydrogen-side pressure leads to a net reduction in cell voltage, overcoming the Nernstian penalty. This behavior is attributed to pressure-induced mitigation of gas bubble coverage, resulting in lower apparent ohmic losses and a 17% reduction in area-specific resistance. To capture this effect, a linear pressure-correction factor, θ p , is introduced in the resistance formulation. Model parameters are identified using a global weighted non-linear least-squares approach. The pressure-corrected model improves accuracy, reducing voltage errors by 33% and lowering the Akaike Information Criterion (AIC). The framework provides a physically grounded tool for real-time control of pressurized AEM systems.