• Title/Summary/Keyword: 고분자전해질형 연료전지

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Effect of hydrogen recirculation in PEM fuel cell with 2D steady-state model (2차원 정상상태 모델을 이용한 고분자전해질형 연료전지의 수소 재순환의 영향)

  • Chung, Hyun-Seok;Ha, Tae-Jung;Kim, Hyo-Won;Cho, Sung-Woo;Han, Chong-Hun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.209-212
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    • 2007
  • 고분자전해질형 연료전지의 구조 및 구성품의 물성에 따른 성능 및 물이동 현상에 관해서 많은 연구가 진행되고 있다, 이들 연구는 대체적으로 연료 전지의 BOP(Balance of plant)를 포함하는 연료전지 시스템에 관한 연구 보다는 단위 전지 및 스택에 관한 연구에 국한되어 왔다. 연료전지의 시스템에 관한 연구들 또한 세부적인 연료전지 내부의 거동에 대해서는 고려하지 않고 있었다. 이는 연료전지의 상세 모델을 이용해 연료전지 시스템에 대해 접근하기 보다는 시스템의 성능 및 동특성에 대한 연구가 주를 이루었기 때문으로 생각된다. 본 연구에서는 연료전지 음극의 수소 배출가스를 재순환할 경우 연료전지 내부에서의 거동에 미치는 영향에 대해 2차원 정상상태 모델을 이용하여 분석해 보았다. 또한 재순환된 수소에 의한 연료전지 내부 거동의 변화 및 수소 이용율 상승 효과를 연료 전지 성능과 함께 비교해 보았다 이를 위해 2차원 정상상태 모델을 개발하였고 이를 실험을 통해 검증하는 작업을 수행하였다. 여기에 사용된 연료전지 모델은 Gore社 의 $PRIMea^{(R)}$을 사용한 연료전지의 성능을 잘 예측하고 내부의 유동 및 물이동 현상에 관한 정보를 제공한다. 이는 여러 하이브리드 자동차용 연료전지 시스템이 연료전지 배출가스의 재순환을 고려하고 있는 상황에서 연료전지 작동 조건의 최적화에 유용한 정보를 제공 할 수 있다는 의의를 가진다.

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Cooling Fluid Study in Proton Exchange Membrane Fuel Cell (고분자전해질형 연료전지의 냉각유체에 대한 연구)

  • 김준범;이흥주
    • 한국전기화학회:학술대회논문집
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    • pp.93-96
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    • 2005
  • 고분자전해질형 연료전지에서는 수소이온의 이온전도성 저하를 방지하기 위하여 외부에서 가습하여 주는 방식이 일반적이지만, 가습에 소요되는 부품을 일부라도 제거할 경우 연료전지의 효율은 높이고 제작단가도 경감할 수 있다. 이를 위하여 저가습 및 무가습 실험을 수행하였으며, 정확한 data의 수집과 시험장비의 자동제어를 위하여 National Instrument사의 compact field point (cFP)를 사용하였다. Humidifier와 heater의 온도를 조절하여 공급유체의 상대습도 및 온도를 각각 조절하였으며, 이에 필요한 이론적 온도는 Antoine equation 을 사용하여 산정하였다. Anode와 cathode 양측 $100\%$ 가습 경우를 기준으로 가습량을 조절하면서 실험을 수행하였으며 성능 차이를 그래프로 도시하여 양측의 변화에 대한 영향을 볼수 있도록 하였다. Stack의 온도가 $70^{\circ}C$이고 양측 무가습일 경우에 성능 측정이 어려워서 stack의 온도를 저온에서부터 변화시키면서 무가습 성능을 실시간으로 측정하여 보았다. 일반적으로 hydronium ion은 anode측에서 cathode측으로 계속 이동하여야 전기를 생성할 수 있으므로 cathode측 무가습이 anode측 무가습보다 성능이 더 잘 나오는 것으로 예측하였으나 이와 반대되는 경향의 실험 결과를 얻었다. 양측 무가습의 경우에는 공기 중의 상대습도와 back diffusion 등에 영향을 받을 수 있으므로 각종 변수들의 영향을 분리하여 관찰할 수 있는 실험을 수행 중에 있다.

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An Experimental Study on Measurement of Oxygen Concentration in the Cathode Channel of PEMFC by Using GC (GC를 이용한 고분자전해질형 연료전지의 공기극 채널 내 산소 농도 분포에 관한 실험적 연구)

  • Ha Taehun;Kim Han-Sang;Min Kyoungdoug
    • 한국신재생에너지학회:학술대회논문집
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    • pp.384-387
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    • 2005
  • Fuel cell has been well known as a clean alternative power for vehicles. Recently, an experimental technique has been developed measurement of species and distributions by using gas chromatograph. In this study, cathode channel oxygen distributions as various conditions were investigated using gas chromatograph and cell visualization. And discussed relation between flooding and oxygen concentrations. As a result of experiment, oxygen consumpt ion is affected wi th flooding. Flooding is observed in channel near hydrogen inlet, and oxygen consumption is low at that region.

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TA Study on the Performance and the Efficiency in Polymer Electrolyte embrane Fuel Cell (고분자전해질형 연료전지의 성능해석 및 효율에 관한 연구)

  • Kim Hong-Gun;Kim Yoo-Shin;Yang Sung-Mo;Nah Seok-Chan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.4
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    • pp.75-80
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    • 2005
  • An experimental study is carried out to investigate the performance and the efficiency humidifying Membrane Electrolyte Assembly and having the double-tied catalyst layers in a fuel cell system which is taken into account the physical and thermal concept. Subsequently, an electric output produced by PEMFC(Polymer Electrolyte Membrane Fuel Cell) is measured to assess the performance of a stack, and the efficiency is also evaluated according to the different situation in which unit cell is placed with and without the humidification of the MEA. It is found that the measured values of stack voltage and current are influenced by the stack temperature, humidification, and the double-tied catalyst layers which give more enhanced values to be applied to electric units.

Numerical Study of Droplet Dynamics in a PEMFC Air Flow Channel (고분자전해질형 연료전지의 공기 채널 내에서의 액적 거동에 대한 수치적 연구)

  • Choi, Ji-Young;Son, Gi-Hun
    • Proceedings of the KSME Conference
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    • pp.2390-2395
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    • 2008
  • The water droplet motion in an air flow microchannel with pores through which water emerges is studied numerically by solving the equations governing the conservation of mass and momentum. The gas-liquid interface is tracked by a level set method which is based on a sharp-interface representation for accurately imposing the matching conditions at the interface and is modified to implement the contact angle conditions on the wall and pores. The numerical results show that the droplet growth and detachment pattern depend significantly on the contact angle and inlet air velocity. Also, the dynamic interaction between the droplets growing on multiple pores is investigated. The pore arrangement subject to droplet merging is found to be not effective for water removal.

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Experimental Study on Carbon Corrosion of Gas Diffusion Layer in PEM Fuel Cell (고분자전해질형 연료전지 가스확산층의 탄소 부식에 관한 실험적 분석)

  • Ha, Taehun;Cho, Junhyun;Park, Jaeman;Min, Kyoungdoug;Lee, Eunsook;Jyoung, Jy-Young
    • 한국신재생에너지학회:학술대회논문집
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    • pp.76.1-76.1
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    • 2010
  • Recently, many efforts to solve the durability problem of PEM fuel cell are carried on constantly. However, despite this attention, durability researches of gas diffusion layer (GDL) are not much reported yet. Generally, GDL of PEM fuel cell experiences three external attacks, which are dissolution of water, erosion of gas flow, corrosion of electric potential. In this study, among these degradation factors, carbon corrosion of electric potential was focused and investigated with accelerated carbon corrosion test. Through the test, it is confirmed that carbon corrosion occurred at GDL, and corroded GDL decreased a performance of operating fuel cell. The property changes of GDL were measured with various methods such as air permeability meter, pore distribution analyzer, thermo gravimetric analyzer, and tensile stress test to discover the effects of carbon corrosion. Carbon corrosion caused not only loss of weight and thickness, but also degradation of mechanical strength of GDL. In addition, to analysis the reason of GDL property changes, a surface and a cross section of GDL were observed with scanning electron microscope. After 100 hours test, the GDL showed serious damage in center of layer.

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Electrode Performance of Pt-Cr-Ni Alloy Catalysts for Oxygen Electrode in Polymer Electrolyte Fuel Cell (고분자전해질형 연료전지에서 산소극을 위한 백금-크롬-니켈 합금촉매의 전극특성)

  • Sim, Jung-Pyo;Lee, Hong-Gi
    • Korean Journal of Materials Research
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    • v.10 no.12
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    • pp.831-837
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    • 2000
  • To improve the catalytic activity of platinum on polymer electrolyte fuel cell(PEFC), platinum was alloyed with cobalt and nickel at various temperature. By XRD, it was observed the crystal structure of alloy catalysts were the ordered face centered cubic(f.c.c) due to the superlattice line at $33^{\circ}$. As heat-treatment temperature was increased, the particle size of alloys also were increased and the crystalline lattice parameters were decreased. According to the results from mass activity, specific activity and Tafel slope measured by cell performance test and cyclic voltammogram, the catalyst activities of alloys are higher than that pure platinum.

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PEMFC performance on reverse voltage by fuel starvation (연료 부족에 의한 고분자전해질형 연료전지의 역전압 성능)

  • Lee, Hung-Joo;Song, Hyun-Do;Kim, Jun-Bom
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.2
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    • pp.133-140
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    • 2006
  • The performance of proton exchange membrane fuel cell was decreased by reverse voltage using fuel starvation. Performance decrease in local area could be affected by duration and extent of reverse voltage. Hydrogen and air stoichiometic ratio was used to find the experimental condition of abrupt voltage decrease. LabVIEW was used to make control logic of automatic load off system in preset voltage. Reverse voltage experiment was done down to -1.2 V at constant current condition. When fuel cell voltage was reached to preset voltage, electronic load was disconnected to make open circuit voltage for 1 minute. Fuel cell performance was checked every 5 cycle and the degree of performance decrease and/or recovery was estimated. Ohmic resistance and charge transfer resistance were increased and platinum surface area was reduced 41% after reverse voltage experiment.

Investigation of Water Droplet Behaviour on GDL Surface and in the Air Flow Channel of a PEM Fuel Cell under Flooding Conditions (플러딩 조건 하에서의 고분자전해질형 연료전지 GDL 표면과 공기극 유로 채널에서의 물방울 유동 특성 고찰)

  • kim, Hansang;Min, Kyoungdoug
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.5
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    • pp.476-483
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    • 2012
  • Proper water management is crucial for the efficient operation of polymer electrolyte membrane (PEM) fuel cell. Especially, for automotive applications, A novel water management that can avoid both membrane dry-out and flooding is a very important task to achieve good performance and efficiency of PEM fuel cells. The aim of this study is to investigate the liquid water behavior on the gas diffusion layer (GDL) surface and in the cathode flow channel of a PEM unit fuel cell under flooding conditions. For this purpose, a transparent unit fuel cell is devised and fabricated by modifying the conventional PEM fuel cell design. The results of water droplet behavior under flooding conditions are mainly presented. The water distributions in the cathode flow channels with cell operating voltage are also compared and analyzed. Through this work, it is expected that the data obtained from this fundamental study can be effectively used to establish the basic water management strategy in terms of water removal from the flow channels in a PEM fuel cell stack.