• 멤브레인
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• 제26권2호
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• pp.141-145
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• 2016

고분자전해질막은 전극 이외에 전기 화학 연료전지의 성능을 결정하는 중요한 요소이다. 고분자전해질막은 가스나 양성자 등의 작은 분자를 선택적으로 수송해야 한다. 고분자전해질막을 투과한 가스는 급속히 전기 화학적 환원을 발생시켜 음극 촉매의 열화를 유발하기 때문에 수소 장벽으로 작동해야 하며 가능한 한 빨리 양성자를 이동시켜야 한다. 지금까지 고분자전해질막의 수소 기체 투과도를 측정하는데 한정된 방법(예 : Constant volume/variable pressure (Time-lag)법)을 사용했다. 그러나 측정의 대부분은 고분자전해질막은 건조된 진공 하에서 이루어진다. 그렇지 않으면 얻어진 수소 투과도는 측정 오차가 커지는 원인이 되기 쉽다. 이 연구에서는 일반적으로 고분자전해질막으로 사용되는 Nafion212의 수소 가스 투과 특성을 온도와 습도가 동시에 제어되는 in-situ 측정 시스템을 이용하여 평가하였다.

• 한국표면공학회지
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• 제48권5호
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• pp.199-204
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• 2015

Recently, fuel cell is a good alternative for energy source. Separator is a important component for fuel cell. In this study, The surface of separator was modified for corrosion resistance and electric conductivity. Reduced graphene oxide (rGO) was made by Staudenmaier's method. Nickel, phosphorus and rGO were coated on 6061 aluminum alloy as a separator of proton exchange membrane fuel cell by composite electroless plating. Scanning electron microscope, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were used to examine the morphology of Ni-P-rGO. Surface images were shown that the rGO was dispersed on the surface of Ni-P electroless plating, and nickel was combined with the un-reduced oxygen functional group of rGO.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.438-442
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• 2006

The degradation of Nafion membrane by hydrogen peroxide was investigated in polymer electrolyte membrane fuel cell (PEMFC). Degradation tests were carried out in a solution of $10{\sim}30%$ hydrogen peroxide containing 4ppm $Fe^{2+}$ ion which is well known as Fenton's reagent at $80^{\circ}C$ for 48hr. Characterization of degraded membranes were examined through the IR, Water-uptake, Ion exchange capacity, mechanical strength and $H_2$ permeability. After degradation, C-F, S-O and C-O chemical bonds of membrane were broken by radical formed by $H_2O_2$ decomposition. Breaking of C-F bond which is the membrane backbone reduced the mechanical strength of Nafion membrane and hence induced pinholes, resulting in increase of $H_2$ crossover through the membrane. Also the decomposition of C-O and S-O, side chain and terminal bond of membrane, decreased the ion exchange capacity of the membrane.

• 멤브레인
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• 제22권3호
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• pp.155-170
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• 2012

연료전지는 석유엔진과 비교하여 높은 전류밀도와 효율성, 그리고 친환경적이기 때문에 21세기 들어 대체 발전시스템으로서 각광받아왔다. 연료전지 시스템에서 고분자 전해질 막은 핵심부품으로써 현재 Nafion막이 연료전지시스템에서 사용 중이지만 높은 제조단가와 고온에서 낮은 전도도를 가지는 단점을 가지고 있다. 그러므로 많은 학자들이 낮은 제조단가, 높은 물리적 특성들을 달성하기 위한 연구를 진행하여 왔으며 연료전지의 상용화와 동시에 고성능의 연료전지의 개발을 위하여 많은 방법들이 개발되어 왔다. 그중, 유무기 복합막은 유기물과 무기물의 물성을 균일하게 조합할 수 있으므로 잠재성을 가지고 있는 제조방법이다. 본고에서는 다양한 무기물이 사용되어 제조된 유무기 복합막의 연구동향에 대하여 조사하였다.

• 설비공학논문집
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• 제19권1호
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• pp.86-93
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• 2007

The PEM (polymer electrolyte membrane) fuel cell is one of the promising fuel cell systems as a new small power generating device for automobiles and buildings. The optimal design of cooling plates installed between MEA (membrane electrode assembly) is very important to achieve high performance and reliability of the PEMFC because it is very sensitive to temperature variations. In this study, six types of cooling plate models for the PEMFC including basic serpentine and parallel shapes were designed and their cooling performances were analyzed by using three-dimensional fluid dynamics with commercial software. The model 3 designed by revising the basic serpentine model represented the best cooling performance among them in the aspect of uniformity of temperature distribution and thermal reliability, The serpentine models showed higher pressure drop than the parallel models due to a higher flow rate.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.89.2-89.2
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• 2011

In automotive applicatons or water vehicles, the polymer electrolyte membrane fuel cell(PEMFC) stack is keep moving while their operation. Especially the inclination environment can take a effect to fuel cell stack perfromance, because this condition can cause a bad effect to water exhaust of fuel cell stack. In this study, a large scale stack(over 100kW power) is inclined upto 30 degree in lengthwise and crosswise using stack lift equipment. And the stack is operated in 10~100% load. No significant change has appeared in crosswise inclined condition and lenthwise low angle. But in lenthwise large angle tilting condition, the fuel cell performance has significantly decreased. And this performance decrease is aggravated in low load. An active water exhaust device is applied to the stack to prevent the performance decrease. And in lenthwise large angle tilting condition, this device cause a good effect to fuel cell stack performance.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.523-530
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• 2019

For the low-Pt electrodes for polymer electrolyte fuel cells (PEMFCs), the optimization of ionomer content for anode catalyst layers was carried out. A commercial catalyst of 20 wt.% Pt/C was used instead of 50 wt.% Pt/C which is commonly used for PEMFCs. The ionomer content varies from 0.6 to 1.2 based on ionomer to carbon ratio (I/C) and the catalyst layer is formed over the electrolyte by the ultrasonic spray process. Evaluation of the prepared MEA in the unit cell showed that the optimal ionomer content of the air electrode was 0.8 on the I/C basis, while the hydrogen electrode was optimal at the relatively high ionomer content of 1.0. In addition, a large difference in cell performance was observed when the ionomer content of the hydrogen electrode was changed. Increasing the ionomer content from 0.6 to 1.0 by I/C in a hydrogen electrode with 0.05 mg/㎠ platinum loading resulted in more than double cell performance improvements on a 0.6 V. Through the analysis of various electrochemical properties in the single cell, it was assumed that the change in ionomer content of the hydrogen electrode affects the water flow between the hydrogen and air electrodes bounded by the membrane in the cell, which affects the overall performance of the cell. A more specific study will be carried out to understand the water flow mechanism in the future, and this study will show that the optimization process of hydrogen electrode can also be a very important cell design variable for the low-Pt and high-performance MEA.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.140-140
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• 2009

The polymer electrolyte membrane fuel cell(PEMFC) with the advantages of low-operating temperature, high current density, low cost and volume, fast start-up ability, and suitability for discontinuous operation becomes the most reasonable and attractive power system for transportation vehicle and micro-grid power plant in a household. 200W PEM-type FCs system was integrated by this study, then the electrical characteristics and diagnosis of the fuel cell were analyzed with variations on mass flow rate and stack temperature. The ranges of the variations are $20{\sim}70^{\circ}C$ on stack temperature and 1~8L/min on $H_2$ volume.

• 한국수소및신에너지학회논문집
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• 제19권3호
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• pp.232-238
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• 2008

Research has been proceeded on fuel cell which is fueled by hydrogen. Polymer electrolyte membrane fuel cell (PEMFC) is promising power source due to high power density, simple construction and operation at low temperature. But it has problems such as high cost, temperature dependent performance. These problems could be solved by experiment which is useful for analysis and optimization of fuel cell performance and heat management. In this paper, when hydrogen flows constantly at the stoichiometry of ${\xi}=1.6$, the performance of the fuel cell stack was increased and the voltage difference between each cells was decreased according to the increase of air stoichiometry by 2.0, 2.5, 3.0. Therefore, the control of air flow rate in the same gas channel is important to get higher performance. Purpose of this research is to expect operation temperature, flow rate, performance and mass transportation through experiment and to help actual manufacture of PEM fuel cell stack.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.578-583
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• 2006

This paper introduces conceptual design of scroll expander-compressor unit for fuel cell. Since air discharged out of the fuel cell stack after reaction has still high pressure energy, some power can be extracted out of it by directing it to pass through an expanding device so that the extracted power can be used to drive an auxiliary compressor. For this purpose, a scroll type expander coupled to a scroll type compressor was designed: orbiting scroll of the expander and that of the compressor were made to share three of common drive pins installed in the mid frame plate, and central cavity in the mid-plate was used as a back pressure chamber to provide axial compliance for both orbiting scrolls. Performance analysis for the expander showed that the shaft power of the expander could reduce the auxiliary power consumption in the fuel cell by about one third at the scroll clearance of $10{\mu}m$.