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

Li, Hui Yan; Guo, Hang; Ye, Fang; Fang, Chong

doi:10.1002/er.4073

Cited by 21 publications

(10 citation statements)

References 26 publications

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“…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.…”

Section: Resultssupporting

confidence: 85%

“…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.…”

Section: Discussionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Guo

et al. 2018

Int J Energy Res

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Summary With the occurrence of reversible electrochemical reactions, mode switching considerably affects the electric performance of unitized regenerative fuel cells (URFCs) owing to the complicated mass and heat transfer. Although limited researches have been done, no such studies on mass and heat transfer through a three‐dimensional view are envisioned during mode switching. A three‐dimensional full‐cell model was developed and validated to study the dynamic characteristics of a proton exchange membrane‐based URFC during mode switching. Mode switching was performed by changing operation voltage from 0.60 to 1.65 V. Results showed that species and heat transfer affect the electric performance of the cell during mode switching, especially through the third dimensional. Local water starvation occurs on oxygen side catalyst layer and thus results in slight reduction on current density and hydrogen generation. Restricted to heat transfer capacity through ribs, heat transfer process adds total response time in URFCs. Heat flux and surface heat transfer coefficient are forecasted on the hydrogen and oxygen sides. A total time of 4 seconds is essential for URFC reaching a new relative balanced state.

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Section: Resultssupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Guo

et al. 2018

Int J Energy Res

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Wagner

Kohnke²

2020

Fuel Cells

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The big challenge of global phase-down of carbon dioxide emissions leads us to alternatives in storing electric energy from renewable sources. For the worldwide use of batteries and fuel cells very high amounts of precious electrode materials are needed. Batteries require rare earth metals and environmentally harmful Lithium, PEM fuel cells require noble platinum and iridium. Thus, an economical and eco-friendly alternative to lithium-ion-batteries should be found, especially for the use in domestic homes. In the on-hand work, a well-known type of fuel cell is revised and considered in the new context of global material usage. Therefore, an alkaline fuel cell with the classic design of an electrolyte gap inbetween the electrodes is observed. Gas-diffusion-electrodes are used, based on Raney-nickel. Results are given for different catalysts: Raney-nickel, Raney-silver, manganic-oxide, carbon and ruthenium. For the analysis current-voltage-characteristics, chronopotentiometry and SEM micrographs are used. The results are discussed in comparison to a unitized reversible PEM fuel cell. At low current density, the alkaline cell is obtaining round-trip efficiencies close to 70%, while the PEM cell achieves only 60% efficiency. With Silver-catalyst clear higher efficiencies up to 80% are presentable. The PEM fuel cell shows obvious better performance at high current densities.

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Jia

Guo

et al. 2019

Int J Energy Res

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Summary In this study, the cell performance of nonuniform depth and conventional straight channel in a unitized regenerative fuel cell (URFC) is compared. Various shapes of oxygen‐side channel cases are also proposed. Several parameters, such as the distribution of reactants and products and current density and powers in fuel cell (FC) and electrolytic cell (EC) modes, are investigated. A steady‐state model of two‐dimensional, two‐phase, nonisothermal, and coupled electrochemical reaction is developed. Five oxygen‐side channel shapes are also designed, in which the depth along the flow direction is narrowed. Result shows that narrowing the average channel depth can promote and guide the reactant transfer to the catalyst layer and avoid the blocking of the production. Thus, in comparison with the conventional channel, the cell performances of nonuniform depth and shallow straight channel cases are improved in both modes. In addition, with the decrease of average channel depth, the temperature uniformity gets better, which is also conductive to the improvement of cell performance. Furthermore, in FC mode at low voltage and EC mode, the cell net power basically increases with the decrease of the average channel depth ratio. And when the average channel depth is the same, the net power of straight channel is always lower than nonuniform depth case. This study introduces the round‐trip energy efficiency as an evaluation indicator of URFC. This efficiency can be increased by improving the cell performance of both modes, especially at high current density.

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

Cited by 21 publications

References 26 publications

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

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

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

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

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