• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.96.2-96.2
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• 2011

Water transport through the microporous membrane was modeled considering capillary condensation as well as capillary flow in porous media as a function of pore diameter and relative humidity at the surface. The present model was adopted by the numerical simulation of non-isothermal, non-homogenous flow in a shell and tube typed gas to gas membrane humidifier for PEMFC (proton exchange membrane fuel cell) and the result shows good agreement with experimental data.

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.390-396
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• 2009

The flooding, especially in channel, is one of the critical issue to put proton exchange membrane fuel cell (PEMFC) to practical use. In this paper, channel flooding was investigated the pressure difference at cathode channel outlet. A ratio of pressure difference changes to 25, 50% as its variation rate. The pressure variable rate is reflected in dimensionless number FN. As a result, modified dimensionless number $FN^*$ correctly predicted the channel flooding. This study analyzes that a variety of pressure difference is how to affect flooding at the cathode of the PEMFC.

• Korean Chemical Engineering Research
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• 제60권1호
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• pp.12-19
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• 2022

소형 이송형 고분자전해질 연료전지 (PEMFC)에 많이 사용되는 cathode 개방형 PEMFC 스택은 내구성이 약한 문제점이 있다. 13개의 셀로 이루어진 PEMFC 스택의 가속 내구성 평가를 통해 스택의 열화 원인을 찾고 cathode 개방형 스택의 내구성 향상에 기여하고자 하였다. Cathode가 대기에 개방되어 있고, 기밀 유지가 어려운 cathode 개방형 스택의 구조적 문제점 때문에 시동/정지 (SU/SD)시 수소/공기 경계가 형성되어 cathode를 열화시킨다. 본 연구에서는 cathode 개방형 스택에 SU/SD 1,800회 반복 후 초기 성능의 54%가 감소하여 비교적 짧은 시간에 내구성을 평가할 수 있었다. 스택 해체 후 각 셀을 2등분하여 성능분석하였다. 전체적으로 공기 유입이 용이한 anode 출구부 MEA가 유입부 MEA보다 전극 열화가 더 심해서 SU/SD시 수소/공기 경계 형성이 주요 열화 원인임을 확인했다.

• Korean Chemical Engineering Research
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• 제52권6호
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• pp.695-700
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• 2014

고분자전해질 연료전지로 물을 전기분해하여 수소와 산소를 발생시킬 수 있다. 그러나 1.7V 이상의 높은 전압에서 수전해 반응이 일어나므로 전극과 고분자 전해질 막의 열화가 빠르게 진행된다. 수전해 과정에서 anode의 열화를 방지하기 위해 촉매로 지지체 없는 $IrO_2$를 보통 사용하는데 본 연구에서는 고분자전해질 연료전지용 Pt/C 촉매를 수전해 반응에 그대로 사용했을 때 전극과 막의 열화 현상을 분석하였다. 1.8~2.0 V 전압 범위에서 수전해 반응 후 고분자 전해질 연료전지 구동 조건에서 I-V, CV, 임피던스, LSV를 측정했다. 수전해 전압이 높을수록 전극과 막의 열화 속도가 증가하였다. 2.0 V에서 1분 동안 수전해 반응했을 때 수소 수율은 88%였고, 전극과 고분자 막이 열화되어 0.6 V에서 성능이 49% 감소하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.539-542
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• 2007

The transient response of PEMFC (proton exchange membrane fuel cell) is important criteria in the application of PEM fuel cell to real automotive system. In this work, using a transparent unit PEM fuel cell, the transient response and cathode flooding during load change are investigated. The cell voltage is acquired according to the current density change($0.3Acm^2$ to $0.6A/cm^2$) under various stoichiometry conditions and different flooding intensities, Also the cathode gas channel images are obtained by CCD imaging system simultaneously. The different level of undershoots appeared at the moment of load changes under different cathode stoichiometries and flooding intensities. The correlation of the dynamic behavior with stoichiometry and cathode flooding is induced from the results of these experiments.

• 대한기계학회논문집B
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• 제33권8호
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• pp.596-603
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• 2009

The performance of proton exchange membrane fuel cell (PEMFC) is seriously changed by the humidification condition which is intrinsic characteristics of the PEMFC. Typically, the humidification of fuel cell is carried out with internal or external humidifier. A membrane humidifier is applied to the external humidification of residential power generation fuel cell due to its convenience and high performance. In this study, a simple static model is constructed to understand the physical phenomena of the membrane humidifier in terms of geometric parameters and operating parameters. The model utilizes the concept of shell and tube heat exchanger but the model is also able to estimate the mass transport through the membrane. Model is constructed with FORTRAN under Matlab/$Simulink^{(R)}$ $\Box$environment to keep consistency with other components model which we already developed. Results shows that the humidity of wet gas and membrane thickness are critical parameters to improve the performance of the humidifier.

• 대한화학회지
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• 제59권5호
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• pp.413-422
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• 2015

연료전지는 수소와 산소를 연료로 하여 전기를 생산해 내는 장치로, 전기분해에 의해 음극에서 생성된 수소이온을 양극으로 전달할 수 있는 전해질을 필요로 한다. 전해질로써 Nafion과 같은 불소계 고체 고분자 막이 개발되어 왔으나, 고온에서의 수소이온 전도도 감소 및 높은 함수율에 따른 안정성 감소 등의 문제로 인해 새로운 연료전지용 고분자 전해질 막의 개발을 필요로 하였다. 본 연구에서는 술폰산기가 밀집된 구조를 갖는 단량체를 이용함으로써 높은 수소이온 전도도를 확보하고 이에 따른 고분자 막의 높은 함수율은 고분자 사슬 내에 나이트릴(CN) 작용기를 친수성 올리고머에 함께 도입함으로써 고분자 사슬간 쌍극자-쌍극자 상호작용을 통해 극복할 수 있도록 하였다. 결과적으로 물리적 가교가 형성된 고분자 막들은 높은 함수율 대비 우수한 치수안정성을 나타내었으며, 모든 조성에서 Nafion-117 고분자막에 비해 낮은 IEC값을 가짐에도 불구하고 보다 높은 전도도를 나타내었다.

• Journal of Electrochemical Science and Technology
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• 제15권1호
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• pp.132-151
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• 2024

Proton exchange membrane fuel cell (PEMFC) has received extensive attention as it is the most common hydrogen energy utilization device. This research not only investigated the effect of obstacle number and shape on PEMFC performance, but also studied the effect of the blockage degree in the channel of PEMFC on its performance. It was found that compared with traditional scheme, longitudinally distributed obstacles scheme can significantly promote reactants transfer to catalyst layer, and the blockage degree in the channel effect PEMFC performance most. The scheme with 10 rectangular obstacles in single channel and 60% channel blockage had the best output performance and the most uniform distribution of reactants and products. Obstacle height distribution can significantly affect PEMFC performance, the blockage degree in the whole basin was large, particularly as the channel was blocked to higher degree in region 2 and region 3, higher net power density and better mass transfer effect can be obtained. Among them, the fuel cell with the blockage degree of 40%, 60% and 60% in region 1, region 2 and region 3 have the best PEMFC output performance and mass transfer, the net power density was 29.8% higher than that of traditional scheme.

• 대한기계학회논문집B
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• 제33권12호
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• pp.1022-1030
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• 2009

Numerical analysis was carried out to investigate the effect of GDL (Gas diffusion layer) porosity on the performance of PEMFC (proton exchange membrane fuel cell). A complete three-dimensional model was chosen for single straight channel geometry including cooling channel. Main emphasis is placed on the heat and mass transfer through the GDL with different porosity. The present numerical results show that at high current densities, the cell voltage is influenced by the GDL porosity while the cell performance is nearly the same at low current densities. At high current densities, low value of GDL porosity results in decrease of the fuel cell performance since the diffusion of reactant gas through GDL becomes slow with decreasing porosity. On the other hand, for high GDL porosity, the effective thermal conductivity becomes low and the heat generated in the cell is not removed rapidly. This causes the temperature of fuel cell to increase and gives rise to dehydration of the membrane, and ultimately increase of the ohmic loss.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.19-25
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• 2012

The efficiency and life time of the Proton Exchange Membrane fuel cell (PEMFC) system is critically affected by incoming gas with humidity which should be maintained properly at normal operating conditions. Typically, incoming gas of automotive fuel cell is humidified by external humidifier but the characteristics of device is rarely reported. In this study, characteristics of water transfer in the membrane humidifiers have been experimentally investigated for flow rates of gas and for different flow arrangement under steady state condition. At first, capability of mass transfer through the membrane is examined at constant temperature. Then, the temperature distribution effect on the capability of mass transfer is tested over various inlet conditions. In summary, this research presents the mass transfer capability of hydrophilic membrane over various operating conditions.