Investigation of the electrochemical performance in alkaline water electrolysis cells based on a 3D multiphysics model: Effect of flow field and electric field

Abstract

Alkaline water electrolysis (AWE) is a promising technology for the industrial production of green hydrogen. However, in the AWE cell, the influence of gas–fluid two–phase flow and electron conduction on the electrochemical performance has not been revealed clearly. In this study, the flow field and the electric field inside a zero-gap AWE cell operated at high pressure are simulated using a 3D multiphysics numerical model. The maximum deviation between the simulated and measured voltage is only 0.18 %. Then, the electrochemical performance of the AWE cell with a mesh flow field is analyzed from the perspective of gas removal and electron conduction. The results show that the conductive column exhibits a negative effect on gas removal at a low inlet velocity, and the fluid distribution effect of the conductive column becomes apparent as the inlet velocity increases. Furthermore, the effect of the tangential velocity and the normal velocity of the electrolyte on the gas removal is considered separately. Moreover, the ohmic loss caused by electron conduction is also found to be responsible for the performance degradation of an AWE cell. This study provides a new perspective on the effect of the flow field on cell performance and justifies the importance of electron conduction on electrochemical performance.