• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.178-183
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• 2004

The main objective of the present study is to analyze the feasibility of fuel cell powered vehicle, which leads to carry out system design and performance analysis. The major design concepts which include battery, driving motor, and fuel cell module are analyzed and discussed for the future development. The traction power of fuel cell vehicle is calculated according to the driving courses specified. Further, the fuel cell stack is analyzed to determine the capacity of stack as a function of velocity for the appropriate power required.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.10
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• pp.981-985
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• 2007

We present a MEMS-based portable Direct Methanol Fuel Cell (micro-DFMC), featured by a platinum sputtered microcolumn electrode and a built-in fuel chamber containing a limited amount of methanol fuel. Also presented is a micro-DMFC stack structure having a common electrolyte sandwiched by the microcolumn electrodes. The single cells with ME16 and PE16 electrodes show the maximum power densities of $31.04{\pm}0.29{\mu}W/cm^2$ and $9.75{\pm}0.29{\mu}W/cm^2$, respectively; thus indicating the microcolumn electrode (ME16) generates the power density (3.2 times) higher than the planar electrode (PE16). The single cell tests of ME16 and ME4 electrodes (Fig.8) show the maximum power of $31.04{\pm}0.29{\mu}W/cm^2$, and $25.23{\pm}2.7{\mu}W/cm^2$, respectively; thus demonstrating the increased window frame reduces the normalized standard power deviation (standard deviation over the average power). The normalized deviation of 0.11 in ME4 cell has been reduced to 0.01 in ME16 cell due to the increased window frames. The maximum power density of 4-cell stack is 15.7 times higher than that of the single cell. 4-cell stack produces the power capacity of 20.3mWh/g during 980min operation at the voltage of 450mV with the load resistance of $800{\Omega}$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.583-584
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• 2012

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.552-552
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• 2005

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.206-209
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• 2004

Mechanical behavior of a fuel stack was studied using an orthotropic material model. The fuel stack is essentially composed of a bipolar plate (BP), a gasket, an end plate, a membrane electrolyte assembly (MEA), and a gas diffusion layer (GDL). Each component is fastened with a suitable pressure. It is important to maintain a suitable contact pressure distribution of BP, because it influences the power efficiency of the fuel cell stack. When it is exposed to high temperature, its behavior must be stable. Hence, we performed stress analysis at high temperature as well as at room temperature. At high temperature, the contact pressure distribution becomes poor. Many patents have shown that using an elastomer can overcome this phenomena. Its effect was also studied. By using an elastomer, we found a good contact pressure distribution at high temperature as well as at room temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.160-164
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• 1991

The effect of various parameters, such as temperature, current density and operating valtage on the performance of phosphoric acid fuel cell stack was studied by using numerical analysis. The utilization ratio of reaction gas, inlet condition of reaction air and cooling air, inlet condition of cooling air flow latin were changed regularly, The results showed good agreements with the existing results and experimental ones.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.2
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• pp.134-142
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• 2012

A bipolar plate is a major component of a fuel cell stack, which occupies 50~60% of the total weight and over 50% of the total cost of a typical fuel cell stack. In this study, a composite bipolar plate is designed and fabricated to develop a compact and light-weight direct methanol fuel cell (DMFC) stack for a small-scale Unmanned Aerial Vehicle (UAV) application. The composite bipolar plates for DMFCs are prepared by a compression molding method using resole type phenol resin as a binder and natural graphite and carbon black as a conductor filler and tested in terms of electrical conductivity, mechanical strength and hydrogen permeability. The flexural strength of 63 MPa and the in-plane electrical conductivities of 191 S $cm^{-1}$ are achieved under the optimum bipolar plate composition of phenol : 18%; natural graphite : 82%; carbon black : 3%, indicating that the composite bipolar plates exhibit sufficient mechanical strength, electrical conductivity and hydrogen permeability to be applied in a DMFC stack. A DMFC with the composite bipolar plate is tested and shows a similar cell performance with a conventional DMFC with graphite-based bipolar plate.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.27-30
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• 2007

This study considers the feasibility of the concentration control of the methanol solution by oscillating flow in the anode channel of passive type Direct Methanol Fuel Cells(DMFC). DMFC stack performance is largely influenced by the fuel concentration. If the fuel concentration is either lower than 0.5M or more than 2M, its performance deteriorates seriously because of the fuel starvation or the fuel crossover. In this respect the optimization of the fuel concentration is crucially important to maximize the DMFC stack performance. In this work, the effects of oscillating actuation in the fuel supply are studied to control the fuel concentration. Two important nondimensional parameters are introduced, each of which represents either the oscillating frequency or the oscillating amplitude. It is shown how these factors affect the stack performance and the efficiency of the DMFC stack.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.6
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• pp.765-772
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• 2011

In this research, the fuel cell system model capable of generating codes in real time was developed to construct of a HIL (Hardware-In-the-Loop) for a SOFC-powered ship. Moreover, the effects of the distribution of the exhaust gas flow rates in a stack, the flow rates of fuels and temperature of air supplied on the temperature characteristics of fuels supplied to the cathode and the anode, the output power of the stack and system efficiency are examined to minimize the temperature difference between fuels supplied to the stack used in a 500kW SOFC system using methane as a fuel. As a result, the temperatures of fuels supplied to the cathode and the anode maintain at 830K when the opening factor of three-way valve located at outlet of turbine is 0.839. Also the process for optimization of methane flow rate considering the fuel cell stack and system efficiency is required to increase the temperatures of fuels supplied to the stack.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.81-87
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• 2017

SOFC(Solid Oxide Fuel Cell) is one of the high-temperature fuel cells, SOFC system and Stack has a high temperature operating Characteristics. These Characteristics cause a lot of trouble in the design of the system and selection materials, securing durability, and securing safety performance. Therefore, For Commercialization and Supply of SOFC, the development of safety performance assessment techniques and evaluation systems should go together. In this study, we analyzed the evaluation items of SOFC Safety performance standards and risk factors of the stack for design of stack safety performance evaluation system. Based on the analyzed data, the evaluation item was deducted for design of stack safety performance evaluation system. Through the results of this study, we expect to facilitate the supply of SOFC and contribute to a safe use environment.