• Transactions of the Korean hydrogen and new energy society
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• v.26 no.2
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• pp.127-135
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• 2015

High-Temperautre Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) with phosphoric acid-doped polybenzimidazole (PBI) membrane has high power density because of high operating temperature from 100 to $200^{\circ}C$. In fuel cell stack, heat is generated by electrochemical reaction and high operating temperature makes a lot of heat. This heat is caouse of durability and performance decrease about stack. For these reasons, heat management is important in HT-PEMFC. So, we developed HT-PEMFC model and study heat flow in HT-PEMFC stack. In this study, we placed coolant plate number per cell number ratio as variable and analysed heat flow distribution in stack.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.85.2-85.2
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• 2010

There is widespread effort to develop polymer membranes in place of Nafion for high temperature polymer electrolyte membrane fuel cell(PEMFC). In our study, SiO2 membranes are arranged by electrospinning method. For impregnation solution, the modified sulfonated poly(ether ether ketone)(SPEEK) polymer is prepared from sulfonation, sulfochlorination, partial reduction and lithiation reaction. The modified polymer is cross-linked with 1,4-diiodobetane in NMP solvent and then blended with Heteropoly acid(HPA). The characterization of membranes is confimed by FT-IR, Thermogravimetry(TGA), water uptake test and single cell performance test for PEMFC, etc. The composite membrane shows satisfactory thermal and mechanical properties. Beside, The membrane exhibits good ion exchange capacity and high proton conductivity. As a result, The composite membrane is promising as an alternative membrane in high temperature PEMFC.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.81.1-81.1
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• 2011

High temperature proton exchange membrane fuel cell (HT-PEMFC) has been regarded as a promising clean energy sources. In this study, a quasi-three-dimensional dynamic model of HT-PEMFC has been developed and the local dynamic characteristics are investigated. The model has the geometrical simplification of 2+1D reduction (quasi-3D). The one-dimensional model consists of nine control volumes in cross-sectional direction to solve the energy conservation and the species conservation equations. Then, the one-dimensional model is discretized into 25 local sections along the gas flow direction to account for gas and thermal transport in channels. With this discretization, the local characteristics of HT-PEMFC such as species conservation, temperature, and current density can be captured. In order to study the basic characteristics of HT-PEMFC, it is important to investigate the local dynamic characteristics. Thus, the model is simulated at various operating conditions and the local dynamic characteristics related to them are observed. The model is useful to investigate the distribution of HT-PEMFC characteristics and the physical phenomena in HT-PEMFC.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.69-72
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• 2008

The local water contents and water transfer characteristics in the PEMFC system were investigated by numerical simulations and experiments. The performance of a lab-scale PEMFC is measured for fully humidified gases conditions and non-humidified ones. In order to observe the local water contents and water transfer characteristics inside PEMFC, the numerical simulation using CFD module on STAR-CD(es-pemfc) were conducted. The results show that the water content was increased as increasing current density, whereas it was decreased in high current density region. Then there was close correlation between high water content and internal temperature inside of MEA, and high current density was observed when internal temperature was dramatically increased.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.439-445
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• 2007

Proton exchange membrane Fuel Cells(PEMFCs) have been spotlighted because of their broad potential application for potable electrical devices, automobiles and residential usages. However, their utilization is limited to low temperature operation due to the electrolyte dehydration at high temperature. High temperature PEMFC operation offers high CO tolerance and easy water management. This review presents development of high temperature($120{\sim}200^{\circ}C$) PEMFC. Especially, PEMFC which is based on acid-doped PBI membrane is discussed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.82.2-82.2
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• 2010

The development of bipolar plate having high efficiency and chemical properties has a major impact on fuel cell applications commercialization. Even though graphite bipolar plate has high electric conductivity and chemical resistance, it has demerits about mass production and brittle property for commercialization. Hence, metallic bipolar plate can be substitute for fuel cell bipolar plate. Although its inadequate corrosion behavior under PEMFC environment lead to a deterioration of membrane by dissolved metal ions, metallic bipolar plate for PEMFC is more suitable for automotive and residential power generation system because of its high mechanical strength, low gas permeability and applicability to mass production. Therefore, several types of coating has been applied to prevent corrosion and oxide film growth and to achieve more high durability. This work presents durability of coated metal bipolar plate for low temperature PEMFC which made for fuel cell vehicle. This results showed surface treatment increase long-term durability, even electric conductivity and corrosion resistance.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.89.1-89.1
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• 2011

The influence of potential and humidity on the electrochemical carbon corrosion in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs) is investigated by measuring $CO_2$ emission at different potentials for 30 min using on-line mass spectrometry. These results are compared with low tempterature polymer electrolyte membrane fuel cells(LT-PEMFCs) operated at lower temperature and higher humidity condition. Although the HT-PEMFC is operated at non humidified condition, the emitted $CO_2$ in the condition of HT-PEMFC is more than LT-PEMFC at the same potential in carbon corrosion test. Thus, carbon corrosion shows a stronger positive correlation with the cell temperature. In addition, the presence of a little amount of water activate electrochemical carbon corrosion considerably in HT-PEMFC. With increased carbon corrosion, changes in fuel cell electrochemical characteristics become more noticeable and thereby indicate that such corrosion considerably affects fuel cell durability.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.2
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• pp.144-154
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• 2016

HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) using PA (phosphoric acid) doped PBI (polybenzimidazole) membrane has been researched for extending the lifetime. However, the existing work on durability of HT-PEMFC focuses on identifying degradation causes of lab scale. The short life time of HT-PEMFC is still the problem for its commercialization. In this paper, an operating method to maximize life time of 5kW HT-PEMFC stack are proposed. The proposed method includes major steps such as minimization of OCV (Open Circuit Voltage) exposure, control of the proper stack temperature, and N2 purging for the stack. This long life operating method was based on the fragmentary results of degradation from previous research works. Experimentally, the 5 kW homemade HT-PEMFC stack was operated for a long time based on the proposed method and the stack successfully can operate within the desired degradation rate for the target life time.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.5
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• pp.442-449
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• 2018

Research on High temperature polymer electrolyte fuel cell (HT-PEMFC) has actively been conducted all over the world. Since the HT-PEMFC can be operated at a high temperature of $120-180^{\circ}C$ using phosphoric acid-doped polybenzimidazole (PBI) electrolyte membrane, it has considerable advantages over conventional PEMFC in terms of operating conditions and system efficiency. However, If the thermal distribution is not uniform in the stack unit, degradation due to local reaction and deterioration of lifetime are difficult to prevent. The thin plate separator reduces the volume of the fuel cell stack and improves heat transfer, consequently, enhancing the cooling effect. In this paper, a large area flow field of thin plate separator for HT-PEMFC is designed and sub-stack is fabricated. We have studied stack performance evaluation under various operating conditions and it has been verified that the proposed design can achieve acceptable stack performance at a wide operating range.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.5
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• pp.569-578
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• 2011

The $SiO_2$ membranes for polymer electrolyte membrane fuel cell (PEMFC) are preapared by electrospinning method. It leads to high porosity and surface area of membrane to accommodate the proton conducting materials. The composite membrane was prepared by impregnating of Nafion ionomer into the pores of electrospun $SiO_2$ membranes. The $SiO_2$:heteropolyacid (HPA) nano-particles as a inorganic proton conductor were prepared by microemulsion process and the particles are added to the Nafion ionomer. The characterization of the membranes was confirmed by field emission scanning electron microscope (FE-SEM), thermogravimetry analysis (TGA), and single cell performance test for PEMFC. The Nafion impregnated electrospun $SiO_2$ membrane showed good thermal stability, satisfactory mechanical properties and high proton conductivity. The addition of the $SiO_2$:HPA nano-particle improved proton conductivity of the composite membrane, which allow further extension for operation temperature in low humidity environments. The composite membrane exhibited a promising properties for the application in high temperature PEMFC.