A comprehensive study of parameters distribution in a short PEM water electrolyzer stack utilizing a full-scale multi-physics model

Abstract

Proton exchange membrane (PEM) electrolyzer is regarded as one of the most promising technologies for hydrogen production. To meet the requirements of large-scale hydrogen production, PEM electrolyzer stack that composed by series units are necessary. However, the composition brings extra problems such as maldistribution from the manifold to each unit, which results in parameters differences among the units and further gives rise to stack degradation. In this study, a full-scale three-dimensional multi-physics model is developed to simulate a short PEM electrolyzer stack with four single electrolyzer units. All the electrolyzer components and connections (e.g. manifold) are included in the model, and the temperature distribution, liquid saturation, membrane water content and electrolyzer performance are investigated in detail. The results indicate that performance of each single electrolyzer decreases from the first to the last unit along the water flow direction. It is recommended that the inlet temperature of electrolyzer stack should not exceed 60°C. To ease the thermal management, the water supply mode for cathode side can obviously lower the stack temperature to a preferred range, and improve the temperature uniformity. This study provides a comprehensive understanding of the distribution behaviors inside the electrolyzer stack and guides the operating parameters optimization.