Experimental investigation on voltage response to operation parameters of a unitized regenerative fuel cell during mode switching from fuel cell to electrolysis cell

Abstract

Summary In this work, a proton exchange membrane unitized regenerative fuel cell with a 25 cm2 active area and a transparent window was designed to study the influence of mode switching from the fuel cell mode to the electrolysis cell mode on the cell voltage and the gas‐liquid two‐phase flow behaviors in the oxygen flow channels. Results indicate that: the growth rate of electrolysis cell voltage before the water pumped to the oxygen flow channels decreases with the increase of the fuel cell current density; while the growth rate of electrolysis cell voltage before the water pumped to the oxygen flow channels increases with the cell temperature; the voltage of electrolysis cell mode before the water pumped to the oxygen flow channels decreases with the increase of water flow rate; the different voltage reduction speeds are attributed to the different water flow rates. The water temperature has an obscure influence on the cell voltage of electrolysis cell mode before the water pumped to the oxygen flow channels.

Heat and mass transfer in a unitized regenerative fuel cell during mode switching

“…This is because the effect of mass transfer along width direction of porous payers cannot be described based on a two‐dimensional model. Noticed that the reduction of the electric performance of the cell switching to EC mode is similar with experimental results in the study of Li, Hang, Ye, and Ma. In experiments, a long water supply tube results in water supply untimely and thus results in a slight reduction of the cell performance.…”

“…An experimental investigation showed that a slight decline of the electric performance occurs in practical operation of a lab-scaled URFC. 18 The authors suggested that untimely water supply results in water starvation, thereby, causes a slight reduction of the voltage. Over experiment, the advantage of numerical simulation is capable to forecast the species and heat distributions within the cell.…”

“…On the other hand, mode switching from FC mode to EC mode is inevitable in future engineering application of the URFC. An experimental investigation showed that a slight decline of the electric performance occurs in practical operation of a lab‐scaled URFC . The authors suggested that untimely water supply results in water starvation, thereby, causes a slight reduction of the voltage.…”

Another Chance for Classic AFCs? Experimental Investigation of a Cost‐Efficient Unitized Regenerative Alkaline Fuel Cell, Using Platinum‐Free Gas Diffusion Electrodes

“…In [14] titanium felts with a high specific surface area are researched for regenerative fuel cells with acidic media. In [15] a unitized regenerative PEM fuel cell was researched during switching form fuel cell to electrolysis mode while water has been pumped into the oxygen gas channels. It was figured out that the rate of the two-phase volume flow and the water temperature have a big influence on a temporary voltage peak.…”

Mass transfer and cell performance of a unitized regenerative fuel cell with nonuniform depth channel in oxygen‐side flow field

“…The distribution of gas-liquid two-phase flow in URFC is important in cell performance. Excessive liquid water easily causes water flooding and seriously hinders the normal operation of URFC due to the existence of gas and liquid in the cell during the actual operation [18][19][20][21][22][23] . Therefore, studying two-phase flow in simulation and reducing flooding phenomenon is important.…”