• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.212-214
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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 PEMFC(Polymer electrolyte membrane fuel cell) system applied to middle and small-scaled micro-grid power system was constructed by this study, then the electrical characteristics and diagnosis of the fuel cell were analyzed with thermal variation.

• 한국군사과학기술학회지
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• 제17권5호
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• pp.694-702
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• 2014

One of the most important devices in an underwater vessel is a propulsion system. It should be a quiet and efficient system for stealthy operations in the large mission area. Hence lead-acid battery system has been used to supply the energy to electric motor. Recent technological developments and improvements, such as polymer electrolyte membrane(PEM) fuel cell and lithium polymer battery and have created the potential to improve overall power and propulsion performance. An underwater vessel always starts their mission with a limited energy and is not easy to refuel. Therefore design of energy elements, such as fuel cell and battery, and their load distribution are important to increase the maximum operating time of underwater vessel. In this paper, the lead-acid battery/PEM fuel cell and lithium polymer battery/PEM fuel cell were suggested as propulsion system and their performances were analyzed by modeling and simulation using Matlab/Simulink. Each model concentrated on representing the characteristics of energy element depending on demand current. As a result the effect of load distribution between battery and fuel cell was evaluated and the operation time of each propulsion system was able to be estimated exactly.

• 한국수소및신에너지학회논문집
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• 제29권4호
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• pp.331-338
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• 2018

In this study, sulfonated PAES block copolymers have been synthesized via nucleophilic substitution reaction. Hydrophobic oligomer was prepared using 2,6-dihydroxynaphthalene and bis(4-chlorophenyl) sulfone, whereas hydrophilic oligomer was prepared using sulfonated bis(4-chlorophenyl) sulfone and bis(4-hydroxyphenyl) sulfone. The chemical structure of polymers was analyzed by $^1H$ NMR, FT-IR and GPC. The thermal properties of polymers were measured by TGA and DSC. The oxidative stability of membranes was investigated by Fenton's test. Furthermore, the proton conductivity of membrane was found to be 26 mS/cm at $90^{\circ}C$. All physiochemical properties suggest that fabricated membrane have a great potential for applications in PEMFC.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.84.1-84.1
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• 2010

Since the discovery of the carbon nanotube(CNTs), they have attracted much attention because of unique properties that may impact many fields of science and technology. The considerable properties of CNTs include high surface area, outstanding thermal, electrical conductivity and mechanical stability. However, uniform deposition of Pt nanoparticles on carbon surface remains inaccessible territory because of the inert carbon surface. In this study, we prepared directly oriented CNTs on carbon paper as a catalyst support in cathode electrode. carbon surface was functionalized using aryl diazonium salt for increasing adhesion of Ni particles which is precursor for growing CNTs. For fabricate electrode, CNTs on carbon paper were grown by chemical vapor deposition using Ni catalyst and Pt nanoparticles were deposited on CNTs oriented carbon paper by polyol method. The performance was measured using Proton electrolyte Membrane Fuel Cell(PEMFC). The structure and morphology of the Pt nanoparticles on CNTs were characterized by Scanning electron Microscopy(SEM) and Transmission electron Microscopy (TEM). The average diameter of Pt nanoparticles was 3nm.

• 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.

• 에너지공학
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• 제25권3호
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• pp.66-72
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• 2016

본 연구에서는 술폰화된 sodium 5,5'-carbonylbis(2-fluorobenzene sulfonate) 단량체를 이용하여 친수성 올리고머를 합성한 뒤 소수성 올리고머와 1:1로 공중합반응을 시켜 sulfonated poly(arylene ether ketone) (SPAEK) 공중합체를 합성하였다. 제조한 공중합체의 구조 분석은 $^1H$-NMR, FT-IR, GPC를 사용하여 실시하였고, GPC에서 공중합체의 평균분자량은 $209,700g\;mol^{-1}$, 다분산지수(PDI)는 1.25이었다. 열적 안정성을 확인하기 위하여 TGA 분석을 실시하였고, $200^{\circ}C$이상에서의 열 안정성을 확인하였다. 고분자 전해질 막의 양이온 전도도는 상대습도 100%, $80^{\circ}C$의 온도에서 약 $9.0mS\;cm^{-1}$이었다. 측정된 결과로부터 본 연구에서 제조한 탄화수소계 전해질 막은 술폰화 정도를 증가시키거나 약간의 구조적 변형을 통해 연료전지용 고분자 전해질 막으로 적용 가능할 것으로 기대된다.

• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.41-55
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• 2018

General polymer electrolyte fuel cell (PEMFC) operates at less than $80^{\circ}C$. Therefore liquid phase water resulting from electrochemical reaction accumulates and floods the cell which in turn increases the mass transfer loss. To prevent the flooding, it is common to employ serpentine flow channel, which can efficiently export liquid phase water to the outlet. The major drawback of utilizing serpentine flow channel is the large pressure drop that happens between the inlet and outlet. On the other hand, in the high temperature polymer electrolyte fuel cell (HT-PEMFC), since the operating temperature is 130 to $180^{\circ}C$, the generated water is in the state of gas, so the flooding phenomenon is not taken into consideration. In HT-PEMFCs parallel flow channel with lower pressure drop between the inlet and outlet is employed therefore, in order to circulate hydrogen and air in the cell less pumping power is required. In this study we analyzed HT-PEMFC's different flow channels by parallel computation using previously developed 3-D isothermal model. All the flow channels had an active area of $25cm^2$. Also, we numerically compared the performance of HT-PEMFC parallel flow channel with different manifold area and Rib interval against the original serpentine flow channel. Results of the analysis are shown in the form of three-dimensional contour polarization curves, flow characteristics in the channel, current density distribution in the Membrane, overpotential distribution in the catalyst layer, and hydrogen and oxygen concentration distribution. As a result, the performance of a real area fuel cell was predicted.

• 에너지공학
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• 제20권3호
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• pp.171-177
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• 2011

본 연구에서는 폴리비닐알코올(PVA)을 전해질 막으로 이용하기 위하여 가교제로서 글루타르알데히드(GLA)와 무기물 첨가제로 알루미늄실리케이트($Al_2O_3{\cdot}3SiO_2$)를 사용하여 PVA/GLA/$Al_2O_3{\cdot}3SiO_2$ 복합막을 제조하였다. PVA/GLA/$Al_2O_3{\cdot}3SiO_2$ 복합막은 GLA의 비율이 증가함에 따라 함수율이 감소되었고, 알루미늄실리케이트 함량이 증가함에 따라 함수율 향상이 예상되어 수소이온 전도도가 향상되는 경향을 보였다. 제조된 고분자의 가교결합은 IR과 함수율의 경향성으로 확인되었다. 제조된 고분자의 열분석은 TGA에 의해 수행되었다. TGA의 분석결과 PVA/GLA 복합막은 가교결합으로 인하여 PVA보다 열안정성이 우수하였으며, 복합막의 알루미늄실리케이트의 비율이 증가할수록 열안정성이 더욱 증대되는 것을 알 수 있었다. 본 연구에서 제조된 복합막은 열안전성을 갖으며 $60^{\circ}C$까지는 양이온전도도가 증가하는 경향을 갖지만 $90^{\circ}C$로 온도가 높아짐에 따라 성능이 낮아지는 경향을 보였다. 따라서 보다 적극적인 노력을 통하여 향후 이온전도성 복합 전해질막으로 적용 가능성을 타진해야 할 것으로 기대된다.

• 전기화학회지
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• 제12권2호
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• pp.142-147
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• 2009

탄소 담지체의 결정도와 형태가 전기화학적 부식특성과 입자뭉침 현상에 미치는 영향을 평가하기 위해서on-line mass spectrometry와 cyclic voltammogram(CV)법을 사용하였다. 부식실험은 단위 전지형태에서1.4 V의 정전압 조건으로 30분간 시행되었으며 이 때 발생한 $CO_2$ 의 양을 on-line mass spectrometry로 측정하였다. 실험 결과 결정성이 높은 carbon nanofiber (CNF)를 사용한 Pt/CNF 촉매가 결정도가 낮은 담지체를 사용한 상용 Pt/C 촉매보다 $CO_2$ 발생량이 적어 전기화학적 부식에 대한 저항성이 큰 것으로 나타났다. 부식실험 전후의 임피던스와 CV측정에서도 탄소 부식의 영향이 적은 Pt/CNF에서 그 변화가 크지 않은 것으로 관찰되었다. 이러한 결과는 탄소 부식이 고분자 전해질형 연료전지(PEMFC)의 내구성을 결정하는 중요한 요소임을 보여준다. 하지만 탄소 부식이 영향을 미치지 않는 조건에서 실시한 반복 CV 실험 결과 촉매 입자 이동에 의한 뭉침현상은 Pt/CNF에서 더 큰 것으로 나타났다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.77.1-77.1
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• 2010

Durability problems of gas diffusion layer(GDL) is one of the important issues for accomplishing commercialization of proton exchange membrane fuel cell(PEMFC). GDL is strongly related to the performance of PEMFC because one of the main function of GDL is to work as a path of fuel, air and water. When the GDL is degraded, it causes water balance problems such as the flooding phenomenon. Thus, investigating the durability characteristics of the GDL is important and understanding the GDL degradation process is needed. In this study, the GDLs are degraded by carbon corrosion stress method which is the electrochemical degradation mode. To determine the effects of carbon corrosion of the GDL, 1.45 V of potential is imposed for 96 hours. In this manner, in the previous research, the structure between the substrate and the MPL is weaken. Further investigations are needed to clarify this phenomenon. Therefore, in this study, the carbon corrosion stress method is carried out with GDLs which have various MPL penetration levels and the effects of the MPL penetration level on the characteristics change of the GDL are analyzed. The changes in characteristics are measured with various properties of GDL such as weight, thickness and static contact angle. The degraded GDL shows loss of their properties.