• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.241-246
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• 2023

Fuel cells are one of the renewable energy sources that have sparked a lot of scientific attention for solving problems related to the energy crisis and environmental pollution. One of the most crucial subjects concerning the utilization of fuel cells is modeling. Therefore, an analytical steady-state and dynamic fuel cell model was described in this study. The parameter for the identification process was investigated, and the MATLAB/Simulink implementation was demonstrated. A 15-W proton exchange membrane fuel cell was used to apply the suggested modeling methodology. Comparing experimental and simulation findings indicated that the model error was constrained to 3%. This study showed that temperature and humidity affect fuel cell performance.

• New & Renewable Energy
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• v.5 no.1
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• pp.11-17
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• 2009

To improve the performance of the anode-supported Solid Oxide Fuel Cell (SOFC) which can be operated at an intermediate temperature, the functional layer (FL) is introduced on a anode substrate. And the scandia-stabilized zirconia (ScSZ) and samaria-doped ceria (SDC) which have higher ionic conductivity and better chemical stability than yttria-stabilized zirconia (YSZ) are used as material for the anode FL with the Ni, The fabrication process of anode-supported single cell with the anode FL was established and the power density of those was evaluated. As a result, the sample with anode FL (Ni-YSZ) has higher power density than normal cell. The single cell which was composed of the FL (Ni-YSZ) and electrolyte (YSZ) showed about $550mW/cm^2$ of the maximum power density at $650^{\circ}C$ and $1430mW/cm^2$ at $750^{\circ}C$ respectively, In case of the single cell using the ScSZ and SDC as anode FL, the performance of samples decreased rapidly and those showed unstable voltage during long-term test. In case of using methane as a fuel, the cell performance with each FL decreased comparing with $H_2$ fuel. In the region of a high current density, there are large concentration polarizations.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.264-266
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• 1997

Fuel cell systems offer high energy efficiencies for transportation application. In addition, they can use alcohols and alternative fuels as the fuel, while producing little or no noxious emissions. Fuel cell-powered vehicles should be competitive in performance characteristics and in capital and maintenance costs with internal combustion engine vehicles. The objective of the present study is to design a fuel cell-powered passenger car to analyze technical feasibility.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.860-864
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• 2005

In this study, we fabricated honeycomb type Mixed-Gas Fuel Cell (MGFC) which has advantages of stacking to the axial direction and increasing volume power density. Honeycomb-shaped anode with four channels was prepared by dry pressing method. Two alternative channels were coated with electrolyte and cathode slurry in order to make cathodic reaction sites and the others were filled with partial oxidation (POX) catalyst to increase fuel conversion. Furthermore we employed the sol-gel technique which can increase cell performance and decrease carbon coking.

• Advances in Energy Research
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• v.8 no.4
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• pp.253-264
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• 2022

This paper deals with the effects of design (active area, current density, membrane conductivity) and operating parameters (temperature, relative humidity) on the performance of hydrogen-fuelled proton exchange membrane (PEM) fuel cell. The design parameter of a PEM fuel cell with the active area of the single cell considered in this study is 25 cm² (5 × 5). The operating voltage and current density of the fuel cell were 0.7 V and 0.5 A/cm² respectively. The variations of activation voltage, ohmic voltage, and concentration voltage with respect to current density are analyzed in detail. The membrane conductivity with variable relative humidity is also analyzed. The results show that the maximum activation overpotential of the fuel cell was 0.4358 V at 0.21 A/cm² due to slow reaction kinetics. The calculated ohmic and concentrated overpotential in the fuel cell was 0.01395 V at 0.76 A/cm² and 0.027 V at 1.46 A/cm² respectively.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.687-693
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• 2019

As the hydrogen fuel cell market is expanded starting from hydrogen electric vehicle and power generation field, the demand for fuel cells and hydrogen increases recently. Therefore, research works on fuel cell durability and fuel efficiency are required in order to activate the fuel cell market and commercialization. A dead-ended anode system was used in this study to optimize the fuel cell performance and fuel efficiency. The effect of purge condition according to the applied current and hydrogen supply pressure on the fuel cell performance were evaluated. In addition, the influence of water back diffusion on the different electrolyte membrane thickness was analyzed. The accumulated water was purged with a solenoid valve in the case of 3% voltage decrease in the dead-ended anode system. The experiment was performed with the hydrogen supply pressure of 0.1~0.5 bar and purge duration of 0.1~1 second. A maximum fuel efficiency of 98.9% was achieved under the purge duration of 0.1 s and hydrogen supply pressure of 0.1 bar with a NR 211 (25.4 um) membrane. However, the fuel cell performance decreased in a long-term operation due to some frequent flooding. The fuel efficiency and purge interval increased due to decreased back diffusion rates of the water and nitrogen with a NR 212 (50.8 um) membrane.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.963-972
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• 2003

Performance characteristics of the planar-type solid oxide fuel cell (SOFC) are investigated by the analysis of flow fields coupled with heat and mass transfer phenomena in anode and cathode channels. For these purposes, performance analysis of the SOFC is conducted based on electrochemical reaction phenomena in electrodes and electrolyte coupled with flow fields in anode and cathode channels. In the present study, the isothermal model adopted in the previous paper prepared by the same authors is extended to the non-isothermal model by solving energy equation additionally with momentum and mass transfer equations using CFD technique. It is found that the difference between isothermal and non-isothermal models come from non-uniform temperature distribution along anode and cathode electrodes by solving energy equation in non-isothermal model. Non-uniform temperature distribution in non-isothermal model contributes to the increase of average temperature of the fuel cell and influences its performance characteristics.

• Journal of the Korean Electrochemical Society
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• v.6 no.3
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• pp.183-186
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• 2003

In a PEM fuel cell electrode, backing layer has tremendous impact on electrode performance. The backing layer provides structural support for the porous electrode, distributes the reactants to the other layers and acts as a current collector. It has major influence on the water management in a PEM fuel cell. Selection of suitable backing layer material for the fabrication of electrode is thus very important to achieve high performance. In this paper we have compared the performance of PEM fuel cell electrodes fabricated using carbon paper EC-TPI-060T, carbon cloth EC-CCI-060T, (ElectroChem Inc.USA) and Carbon cloth from Textron, USA (CPW 003 grade). Mass transport problem was observed under non-pressurized condition, at high current densities, in the caie of EC-CC1-060T carbon cloth electrode (at $50^{\circ}C$), due to its higher thickness. The performance of carbon paper electrode was higher than EC-CCI-060T carbon cloth electrode. The performance of Textron carbon cloth was comparable to EC-TPI -060T carbon paper.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.11
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• pp.697-704
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• 2016

Coal modified by acid treatment was investigated to analyze the correlation between the cell performance and electrochemical parameters in a direct carbon fuel cell (DCFC). The fuels were subjected to thermogravimetry analysis, gas adsorption test, and X-ray photoelectron spectroscopy to investigate the fuel properties and surface characteristics. After the treatment of raw coal, the thermal reactivity of the treated fuels increased, and the specific surface area decreased, though the mean pore diameters of three fuels were similar. The coal treated by $HNO_3$ showed the highest ratio of oxygen to carbon, and also an increase in the surface oxygen groups on the fuel surface. Through comparison between the fuel surface properties and electrochemical performance, it was confirmed that the surface oxygen groups have an influence on the improvement in the DCFC performance.

• Journal of the Korean Society of Visualization
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• v.19 no.2
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• pp.56-62
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• 2021

Solid oxide fuel cells (SOFCs) is the high efficiency fuel cell operating at high temperatures ranging from 700-1000℃. Design of the flow paths of the fuel and air in SOFCs is important to improve cell performance and prevent cell degradation. However, the uneven distribution of current density in the traditional type having one inlet and outlet causes cell degradation. In this regard, the parallel flow path with two inlet and outlets was designed and compared to the traditional type based on computational fluid dynamics (CFD) simulation. To check the cell performance, hydrogen distribution, velocity distribution and current density distribution were monitored. The results validated that the parallel designs with two inlets and outlets have a higher cell performance compared to the traditional design with one inlet and outlet due to a larger reaction area. In case of uniform-type paths, more uniform current density distribution was observed with less cross-sectional variation in flow paths. In case of contracted and expanded inflow paths, significant improvement of performance and uniform current density was not observed compared to uniform parallel path. Considering SOFC cell with uniform current density can prevent cell degradation, more suitable design of SOFC cell with less cross-sectional variation in the flow path should be developed. This work can be helpful to understand the role of flow distribution in the SOFC performance.