• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.12
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• pp.1022-1030
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• 2009

Numerical analysis was carried out to investigate the effect of GDL (Gas diffusion layer) porosity on the performance of PEMFC (proton exchange membrane fuel cell). A complete three-dimensional model was chosen for single straight channel geometry including cooling channel. Main emphasis is placed on the heat and mass transfer through the GDL with different porosity. The present numerical results show that at high current densities, the cell voltage is influenced by the GDL porosity while the cell performance is nearly the same at low current densities. At high current densities, low value of GDL porosity results in decrease of the fuel cell performance since the diffusion of reactant gas through GDL becomes slow with decreasing porosity. On the other hand, for high GDL porosity, the effective thermal conductivity becomes low and the heat generated in the cell is not removed rapidly. This causes the temperature of fuel cell to increase and gives rise to dehydration of the membrane, and ultimately increase of the ohmic loss.

• Journal of Hydrogen and New Energy
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• v.23 no.1
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• pp.19-25
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• 2012

The efficiency and life time of the Proton Exchange Membrane fuel cell (PEMFC) system is critically affected by incoming gas with humidity which should be maintained properly at normal operating conditions. Typically, incoming gas of automotive fuel cell is humidified by external humidifier but the characteristics of device is rarely reported. In this study, characteristics of water transfer in the membrane humidifiers have been experimentally investigated for flow rates of gas and for different flow arrangement under steady state condition. At first, capability of mass transfer through the membrane is examined at constant temperature. Then, the temperature distribution effect on the capability of mass transfer is tested over various inlet conditions. In summary, this research presents the mass transfer capability of hydrophilic membrane over various operating conditions.

• Membrane Journal
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• v.18 no.4
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• pp.336-344
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• 2008

This manuscript deals with the investigation of the possibility of the crosslinked poly(vinyl alcohol) membranes with both poly(styrene sulfonic acid-co-maleic acid) and 3-(trihydroxysilyl)-1-propanesulfonic acid (THS-PSA) for the fuel cell application. The studies were focused on the characterization of the resulting membranes through water content, thermal gravimetric analysis, ion exchange capacity, ion conductivity and methanol permeability measurements and then compared with the existing Nafion membrane. Typically, the ion conductivity lied in the range of $10^{-3}$ to $10^{-2}\;S/cm$ while the methanol permeability showed the range of $10^{-6}$ to $10^{-8}\;cm^2/s$.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.1
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• pp.37-44
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• 2013

In this paper, the characteristics of portable fuel cell system are introduced and the dynamic response of output voltage of fuel cell stack with internal humidifier is analyzed. When the output of the fuel cell (FC) stack is short-circuited for humidification, the output voltage of the FC stack rapidly drops. In order to maintain the load voltage in the required range, dynamic compensation methods are proposed: 1) installing a capacitor behind the output of the FC stack; 2) utilizing the bi-directional converter. Especially, bi-directional converter is used when short of the FC output is detected or predicted by algorithm using data which is measured during previous three cycles. These methods are simulated by PSIM 9.0, then experimental results from the fuel cell system prototype verify the validity of the proposed methods.

• Journal of Hydrogen and New Energy
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• v.21 no.2
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• pp.143-148
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• 2010

Research and Development (R&D) investment of hydrogen and fuel cell, funded by government from 2007 to 2008 in Korea, has been analyzed. R&D investment of hydrogen and fuel cell in 2008 would see 9% and 29% of total budget in the field of renewable energy, respectively. It was found that R&D investment is mainly dependent on mission of Ministry in Korea. Basic and apply research would be mainly invested by Ministry of Education, Science and Technology (MEST), while development research would be conducted by Ministry of Knowledge Economy (MKE). In R&D investment by performer, hydrogen technology would be conducted by government-funded institute and university. It was also shown that funds for hydrogen production have been much supported than hydrogen storage. Meanwhile, fuel cell would be mainly conducted by major companies. It was also shown that funds for proton exchange membrane fuel cell (PEMFC) have been much invested than other technology in fuel cell.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.230-234
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• 2005

Fabrication of MEA is important factor for proton exchange membrane fuel cell (PEMFC). MEA of PEMFC with hot pressing and direct coating method were prepared, and performances were evaluated and compared each other. The effect of MEA preparation methods, hot pressing methods and direct coating methods, on the cell performance was analyzed by impedance spectroscopy and SEM. The performance of PEMFC with direct coating method was better than with hot pressing method because membrane internal resistance and membrane-interfacial resistance were reduced by elimination of hot pressing process in MEA fabrication. In addition the micro structure of MEA with direct coating method reveals uniform interface between membrane and catalyst layer.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.105-108
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• 2007

Fuel cell with high electric efficiency has many probabilities of commercial use. Especially, proton exchange membrane fuel cell (PEMFC) which is a low temperature fuel cell and has less influence on $CO_2$ concentration is considered the power generation system of small building and household. We calculated the optimal operational plans of 1 kW household PEMFC power system based on the daily electricity and heat demand patterns of Japan and Korea. Calculated results show that the economic feasibility of PEMFC power system is very sensitive to the cost policy of electricity and natural gas.

• Journal of Hydrogen and New Energy
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• v.20 no.5
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• pp.390-396
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• 2009

The flooding, especially in channel, is one of the critical issue to put proton exchange membrane fuel cell (PEMFC) to practical use. In this paper, channel flooding was investigated the pressure difference at cathode channel outlet. A ratio of pressure difference changes to 25, 50% as its variation rate. The pressure variable rate is reflected in dimensionless number FN. As a result, modified dimensionless number $FN^*$ correctly predicted the channel flooding. This study analyzes that a variety of pressure difference is how to affect flooding at the cathode of the PEMFC.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.1-7
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• 2005

PEMFC (Proton Exchange Membrane Fuel Cell) is considered as an attractive option to produce electric power in manyapplications. A fundamental step of theoretical fuel cell open circuit potential is examined and compared with the measured data from 1.2KW PEMFC module. The hydrogen pressure and stack temperature are also measured during the operation of PEMFC module. It is found that the stack voltage and current data agree in general with the results calculated by chemical potential approach though they still have a discrepancy. It is analysed that the discrepancy is due to activation polarization, concentration overvoltage and ohmic overvoltage.

• Advances in materials Research
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• v.6 no.2
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• pp.129-153
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• 2017

Platinum is a transition metal that is very resistant to corrosion. It is used as catalyst for converting methyl alcohol to formaldehyde, as catalytic converter in cars, for hydrocracking of heavy oils, in Fuel Cell devices etc. Moreover, Platinum compounds are important ingredient for cancer chemotherapy drugs. The nano forms of Platinum due to its unique physico-chemical properties that are not found in its bulk counterpart, has been found to be of great importance in electronics, optoelectronics, enzyme immobilization etc. The stability of Platinum nanoparticles has supported its use for the development of efficient and durable proton exchange membrane Fuel Cells. The present review concentrates on the use of Platinum conjugated with various metal or compounds, to fabricate nanocomposites, to enhance the efficiency of Platinum nanoparticles. The recent advances in the synthesis methods of different Platinum-based nanocomposites and their applications in Fuel Cell, sensors, bioimaging, light emitting diode, dye sensitized solar cell, hydrogen generation and in biosystems has also been discussed.