A complete polarization model of a solid oxide fuel cell and its sensitivity to the change of cell component thickness

Chan, Siew Hwa; Khor, K.A.; Xia, Zetao

doi:10.1016/s0378-7753(00)00556-5

Cited by 812 publications

(430 citation statements)

References 7 publications

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“…Furthermore, to draw the I − V curve, both voltage and the corresponding cell current density must be considered. To obtain the I − V curve, cell current is fixed and the corresponding voltage is calculated [28] by taking into account of different polarization losses based on the empirical data of the fabricated cell. It is worthy to note that for any fuel cell, the operating potential can be calculated as the departure from ideal voltage caused by the various polarizations [29]:…”

Section: Cathode and Anode Overpotentialmentioning

confidence: 99%

An air-breathing microfluidic formic acid fuel cell with a porous planar anode: experimental and numerical investigations

Shaegh¹,

Nguyen²,

Chan³

2010

J. Micromech. Microeng.

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Abstract. This paper reports the fabrication, characterization and numerical simulation of an air-breathing membraneless laminar flow-based fuel cell (LFFC) with carbon-fiber-based paper as anode. The fuel cell uses 1 M formic acid as the fuel. Parameters from experimental results were used to establish a three-dimensional numerical model with COMSOL Multiphysics. The simulation predicts the mass transport and electrochemical reactions of the tested fuel cell using the same geometry and operating conditions. Simulation results predict that the oxygen concentration over air-breathing cathode is almost constant for different flow rates of fuel and electrolyte. In contrast, growth of depletion boundary layer of fuel over anode can be the major reason for low current density and low fuel utilization. At a low flow rate of 10 µl/min, simulation results show a severe fuel diffusion to the cathode side, which is the main reason for the degradation of open-circuit potential from 0.78 V at 500 µl/min to 0.58 V at 10 µl/min as observed in experiments. Decreasing the total flow rate fifty times from 500 µl/min to 10 µl/min only reduces the maximum power density approximately two times from 7.9 mW/cm 2 to 3.9 mW/cm 2 , while fuel utilization increases from 1.03% to 38.9% indicating a higher fuel utilization at low flow rates. Numerical simulation can be used for further optimization, to find a compromise between power density and fuel utilization.

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Section: Cathode and Anode Overpotentialmentioning

confidence: 99%

An air-breathing microfluidic formic acid fuel cell with a porous planar anode: experimental and numerical investigations

Shaegh¹,

Nguyen²,

Chan³

2010

J. Micromech. Microeng.

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“…Fuller et al's method 39 was applied to determine the ordinary binary diffusion coefficients, and the method reported by Chan et al 37 was used to calculate the Knudsen diffusion coefficients and the overall effective diffusion coefficients. The anode and cathode effective diffusion coefficients and ␦ O 2 were calculated using the equations reported by Chan et al 37 The y i 0 terms in Eq. 17 and 18 are the gas molar fractions in the bulk flow, taken as the average values of the anode and cathode inlet and outlet streams.…”

Section: Reversible Nernst Voltagementioning

confidence: 99%

Simulation of a Tubular Solid Oxide Fuel Cell Stack Operating on Biomass Syngas Using Aspen Plus

Doherty¹,

Reynolds²,

Kennedy³

2010

J. Electrochem. Soc.

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A tubular solid oxide fuel cell stack was modeled, and its operation on biomass syngas was investigated. The objective of this work was to develop a computer simulation model of a biomass gasification–solid oxide fuel cell system capable of predicting performance under various operating conditions and using diverse fuels. The stack was modeled using Aspen Plus and considers ohmic, activation, and concentration losses. It was validated against published data for operation on natural gas. Operating parameters such as fuel and air utilization factor ( Unormalf and Unormala , respectively), current density j , and steam to carbon ratio (STCR) were varied and had significant influence. The model was run on wood and miscanthus syngas. The results indicated that there must be a trade-off between voltage, efficiency, and power with respect to j and that the stack should be operated at a low STCR and a high Unormalf . Also, the stack should be operated at a Unormala of ∼20% . Operation on biomass syngas was compared to natural gas operation and, as expected, performance degraded. Better stack performance was observed for wood syngas compared to miscanthus syngas. High efficiencies were predicted making these systems very promising.

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“…(29) and (30) and plotted in terms of Φ e,c − E rev,c and Φ e,a − E rev,a (31)) of the Butler-Volmer equation (Chan et al, 2001). The evolution of the electric potential of the ionic phase across the cell thickness stands for the ohmic losses, η ohm .…”

Section: Computational Grid and Simulation Techniquesmentioning

confidence: 99%

“…Another class of studies exists, consisting of studies which do not aim to model the cell as a whole, but focus on the analysis of phenomena occurring locally in the porous electrodes and/or in the electrolyte (Chan et al, 2001;Ciucci and Goodwin, 2007;Fleig, 2002Fleig, , 2003Hao and Goodwin, 2007;Kenney and Karan, 2004;Lehnert et al, 2000;Søgaard et al, 2006;Suwanwarangkul et al, 2003;Zhu and Kee, 2007). Polarization mechanisms, charge transfers and heterogeneous reactions are among their interests.…”

Section: Introductionmentioning

confidence: 99%

“…However, concentration losses may become significant because of gas diffusion resistances in the electrodes. It has been shown that an anode-supported cell can operate with a wider range of current density and yield higher power densities than a cathode-supported cell (Chan et al, 2001). The couplings of micro processes such as mass and heat transport, chemistry, electrochemistry and charge transfer occurring in the porous electrodes as well as in the electrolyte are crucial for the overall performance of the cell/stack, however, these processes are fairly far from being well understood.…”

Section: Introductionmentioning

confidence: 99%

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Numerical modeling of solid oxide fuel cells

Kosinski

Hoffmann

et al. 2008

Chemical Engineering Science

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This paper presents a numerical model for a planar solid oxide fuel cell (SOFC) with mixed ionic-electronic conducting electrodes. Transport of positive or negative charges, which takes place in the direction of down-or up-gradient electric potential, respectively, within the composite electrodes and through the electrolyte membrane, is mimicked by making use of an algorithm for Fickian diffusion in the commercial software. The output cell voltage, which is the potential difference between the two current collectors, is fixed at a given value. The coupled equations describing the conservation of mass, momentum and energy and the chemical and electrochemical processes are solved using the commercial package Star-CD, augmented with subroutines developed in-house. Results for the concentration of chemical species and the distributions of temperature and current density in an anode-supported SOFC with direct internal reforming are presented and discussed. The potential for using this model as a general numerical tool to study the impact of the detailed processes taking place in solid oxide fuel cells is discussed.

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A complete polarization model of a solid oxide fuel cell and its sensitivity to the change of cell component thickness

Cited by 812 publications

References 7 publications

An air-breathing microfluidic formic acid fuel cell with a porous planar anode: experimental and numerical investigations

An air-breathing microfluidic formic acid fuel cell with a porous planar anode: experimental and numerical investigations

Simulation of a Tubular Solid Oxide Fuel Cell Stack Operating on Biomass Syngas Using Aspen Plus

Numerical modeling of solid oxide fuel cells

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