Grid-Oriented multiphysics model of Power-to-Hydrogen electrolyzers

Abstract

This paper proposes a multiphysics model of Power-to-Hydrogen electrolyzer that possesses outperforming mathematical properties for fast calculation. The proposed model features a one-dimensional linear diphasic-flow model to describe the bubble effect in low-temperature water electrolysis, which is a crucial physical process affecting cell performance. According to the characteristics of the multiphysics in electrolysis cells, the bubble layer is introduced to only solve the bubble distributions near the electrodes, decreasing the computing scale compared with traditional Calculating Fluid Dynamics (CFD) models. Besides, by the homogeneous flow assumptions and the liquid-phase steady parallel flow, the analytical solution of the momentum conservation is derived to eliminate the nonlinearity of the Naiver-Stokes equation. Once the thickness of the bubble layer is determined, the proposed model can be computed over 10 times faster than the traditional diphasic-flow models, at the expense of the accuracy loss of the i-V characteristics within 0.5%. As a result, the model can be applied to the integrated simulation in the energy system to efficiently acquire both operating characteristics and the multiphysics of the PtH electrolyzer.