Dynamic response during mode switching of unitized regenerative fuel cells with orientational flow channels

Abstract

Oxygen side flow channel structures have significant influence on the dynamic response of relevant parameters in operation mode switching procedures of a unitized regenerative fuel cell. In this paper, an unsteady, non-isothermal, two-phase, two-dimensional unitized regenerative fuel cell model is established to study the dynamic response of two-phase species concentration distributions, current density distributions etc. when the cell mode swiches from the fuel cell mode to the electrolyzer when using orientational flow channel at the oxygen side. The influence of eight oxygen-side channels on the mode switching process is compared. Results show that the required time for each parameter reaching the stable state in the fuel cell mode is longer than the dynamic response time after switching to electrolytic cell mode when using orientational flow channels. In addition, different flow channel structures at the oxygen-side affect the time requirement for stabilizing each parameter during mode switching, while they do not change the characteristics of the stable state mode.