Variation of Two-Phase Species Distribution inside a Unitized Regenerative Fuel Cell during an Electrolytic Cell Mode

Abstract

A three-dimensional electrolytic cell model coupling the two-phase mass transportation behaviors in the unitized regenerative fuel cell is established. This simulation work mainly studies the distribution rule of species inside the electrolytic cell and analyzes the liquid water saturation in inlet and working voltage, respectively. The results show that the high saturation of liquid water at the inlet can increase the oxygen concentration in the catalytic layer on the oxygen side, and the oxygen concentration gradually reduces following the direction of the catalytic layer to the gas channel, and the oxygen concentration is increased with the direction from the inlet to outlet. When the cell voltage increases from 1.35 to 1.95 V, from the catalytic layer to the gas channel, the change rate of liquid water saturation increases from 0.38 to 12.89%, the change rate of hydrogen concentration increases from 0.37 to 1.70%, and the change rate of oxygen concentration decreases from 90.48 to 80.48%. It is concluded that with the increase of electrolytic cell voltage, the gas production rate increases. On the hydrogen electrode side, the high gas yield makes it easier for hydrogen discharge from the cell.