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GDL 기재 형상에 따른 연료전지 막의 손상에 관한 연구
백경돈(Kyung Don Baik),공임모(Im Mo Kong),김민수(Min Soo Kim),홍보기(Bo Ki Hong),한국일(Kook Il Han) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
The compression pressure of polymer electrolyte membrane fuel cells for vehicle applications is typically high enough to minimize contact resistance among the cell components such as membrane electrode assembly (MEA), gas diffusion layer (GDL), and bipolar plate. However, an excessive compression pressure may cause a durability problem since the carbon fibers in the GDL may penetrate into the membrane through catalyst layer of MEA. In this study, the effects of two GDLs with different micro-porous layers, either rough (GDL-1) or smooth (GDL-2) surface, on the open circuit voltage (OCV) have been closely examined. It was observed that the OCV of GDL-1 was decreased more than that of GDL-2 with increasing compression pressure. The concentration of hydrogen crossover of GDL-1 was increased more than that of GDL-2 with compression pressure, implying that the degree of penetration into membrane of GDL-1 should be higher than that of GDL-2.
연료전지 자동차 적용을 위한 소형 PEMFC 시스템 개발
백경돈(Kyung Don Baik),김성일(Sung Il Kim),공임모(Im Mo Kong),김민수(Min Soo Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
The polymer electrolyte membrane fuel cell (PEMFC) has been suggested as a promising alternative to the traditional internal combustion engine for future transportation applications. To meet such demands, PEMFC systems have been studied extensively since the late 1990s. In this study, the new concept of fuel cell system was developed and adopted to the fuel cell vehicle (FCV). Both hydrogen and air recirculation systems are adopted for reducing the volume of the fuel cell system. The 3 kW of the fuel cell stack performance was measured under the dry feeding condition. The performance of air recirculation system was also investigated to identify the effect of the air recirculation on the gas humidification. Results show that if the exhaust air was recirculated largely, the performance of fuel cell stack decreased because of the reduced air mole fraction in the air feeding gas. However, the performance drop of the fuel cell stack reduced as the air recirculation ratio decreases, implying that there is an optimum value of air recirculation ratio.
고분자 전해질 연료전지의 GDL 이방성이 채널로의 GDL 침투에 미치는 영향에 관한 연구
백경돈(Kyung Don Baik),홍보기(Bo Ki Hong),김민수(Min Soo Kim) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5
The effects of the metallic bipolar plate (MBP) structure on the performance of polymer electrolyte membrane fuel cells with gas diffusion layers (GDLs) having anisotropic bending stiffness have been investigated. The Ⅰ-Ⅴ performances of the fuel cells with 90˚ GDLs, whose directions of higher stiffness are perpendicular to the direction of the major flow field, were higher than those with 0˚ GDLs, whose directions of higher stiffness are parallel with the direction of the major flow field. As the land/channel width ratio increased (i.e., wider land width), the Ⅰ-Ⅴ performances of both 0˚ and 90˚ GDL cells increased, presumably due to less GDL intrusion and more intimate contact. However, an excessively large land width greatly decreased the Ⅰ-Ⅴ performances because of the reduced channel width for mass transport. As the land/channel width ratio increased, the high frequency resistance (HFR) values of the cells decreased due to better contact, but the air pressure differences of cathode increased due to the reduced channel width. The differences of Ⅰ-Ⅴ performances and HFR values between the 0˚ and 90˚ GDL cells gradually reduced with increasing land/channel width ratio, because of the reduced anisotropic stiffness effects of the GDLs due to the better support by the MBPs with wider lands.
백경돈(Kyung Don Baik),김성일(Sung Il Kim),공임모(Im Mo Kong),김민수(Min Soo Kim) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Gas crossover through the membrane is well known phenomena in PEM fuel cells. Characterization of oxygen crossover which represents the permeation was investigated in this study. Oxygen crossover from the cathode side to the anode side causes the carbon corrosion which affects the fuel cell durability. Thus it is important to analyze the characterization of oxygen crossover in PEM fuel cells at various conditions such as different cell temperature and relative humidity of supplying gases. In this study, mass spectrometer has been applied at anode exit stream to measure the amount of oxygen crossover at OCV condition. Instead of supplying hydrogen gas, helium gas was supplied at anode side because helium gas does not react with oxygen gas at anode side. Results show that temperature and relative humidity affect the oxygen crossover. As temperature increases, anode exit concentration of oxygen decreases due to the change of oxygen concentration at cathode side.
고분자 연료전지 스택에서 질소 크로스오버 특성에 관한 연구
백경돈(Kyung Don Baik),김민수(Min Soo Kim) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.3
Crossover of nitrogen from cathode to anode is inevitable in typical membranes used in PEM fuel cells. This crossovered nitrogen normally accumulates in the hydrogen recirculation system at anode side channels. Excessive buildup of nitrogen in the anode side lowers the relative hydrogen concentration and finally affects the performance of fuel cell stack. So it is very important to analysis the nitrogen gas crossover at various operating conditions. In this study, characterization of nitrogen gas crossover in PEM fuel cell stack was investigated. The mass spectroscopy (MS) has been applied to measure the amount of the crossovered nitrogen gas at the anode exit. Results show that nitrogen gas crossover rate was affected by current density, anode and cathode stoichiometric ratio and operating pressure. Current density, anode stoichiometric ratio and anode operating pressure do not affect nitrogen crossover rate but anode exit concentration of nitrogen. Cathode pressure and stoichiometric ratio largely affect the nitrogen crossover rate.
고분자 연료전지 스택에서 질소 크로스오버 특성에 관한 연구
백경돈(Kyung Don Baik),김민수(Min Soo Kim) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Crossover of nitrogen from cathode to anode is inevitable in typical membranes used in PEM fuel cells. This crossovered nitrogen accumulates in anode recirculation system and excessive buildup of nitrogen in the recirculating anode gas lowers the hydrogen concentration and finally affects the performance of fuel cell stacks. In this study, characterization of nitrogen gas crossover was investigated in PEM fuel cell stacks. The mass spectroscopy (MS) has been applied to measure the amount of the crossovered nitrogen at the exit of anode. Results show that anode and cathode stoichiometric number (SR<SUB>c</SUB>) have a big effect of nitrogen crossover.
고분자 전해질 막 연료전지에서 수소 크로스오버 특성에 관한 연구
백경돈(Baik Kyung Don),공임모(Kong Im Mo),정애리(Jung Aeri),김민수(Kim Min Soo) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
In this study, the effects of operating parameters including temperature, relative humidity, hydrogen pressure and membrane thickness on hydrogen crossover have been investigated. It is found that hydrogen crossover increases proportionally to the increase in both temperature and relative humidity for all membrane samples. The increase in hydrogen crossover is also observed with increasing hydrogen pressure. A comparison among all of the operating parameters on hydrogen crossover is analyzed using a multiple linear regression analysis. The results indicate that the main factors causing increase in hydrogen crossover are in the order of membrane thickness, hydrogen pressure, RH, and temperature.
고분자 전해질 막 연료전지 시스템에서 공급기체 맥동을 이용한 플러딩 해소 방안 연구
김성일(Sung Il Kim),백경돈(Kyung Don Baik),공임모(Im Mo Kong),김영상(Young Sang Kim),김민수(Min Soo Kim) 대한설비공학회 2012 대한설비공학회 학술발표대회논문집 Vol.2012 No.11
Water flooding is very critical problem especially at low temperature and high current densities in PEMFC. Cathode flooding is more harsh than anode flooding at operating in open mode, however, anode flooding can be serious when the fuel cell is operated with hydrogen recirculation system. In this research, the mitigation method of water flooding is studied by pulsating flow of reactant gas in hydrogen recirculation system with ejector. The experimental results shown that the pulsating flow affects the movement of water in the fuel cell and it extend the period of anode purge. Moreover, it is also found that the anode pulsating effect also affects the movement of water in the cathode.