A comprehensive review of flow channel designs and optimizations for water electrolysis technology

Electrolysis of water to produce hydrogen is a rosy way to utilize renewable energy sources. In the common water electrolysis technologies: proton exchange membrane (PEM) water electrolysis, alkaline water electrolysis (AWE), solid oxide electrolysis cell (SOEC) and anion exchange membrane (AEM) water electrolysis, the flow channel directly correlates with the flow distribution and pressure drop. The uniform flow distribution ensures sufficient reactant supply and timely product discharge in the electrolyzer, which facilitates electrolytic efficiency and uniform temperature distribution, while the lower pressure drop reduces the energy consumption of pumping water. This paper introduces the researches related to the existing flow channel design in four water electrolysis technologies and compares the strengths and weaknesses of different designs, and discusses the objectives and optimization direction. Enhancing heat and mass transfer capability is the main goal of flow channel design, but this performance improvement is generally accompanied by an increase in pressure drop, which increases energy consumption. The choice of flow channel needs to take into account the advantages of all aspects of performance. Finally, the challenges encountered in the design of flow channels are pointed out and a prospect based on the newly introduced research methods is given.