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고분자 전해질막 연료전지에서 수소 크로스오버에 의한 물 생성에 관한 연구
공임모(Im Mo Kong),정애리(Aeri Jung),김민수(Min Soo Kim) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
Hydrogen crossover through a membrane is an inevitable phenomenon in a polymer electrolyte membrane fuel cell (PEMFC). Also, the hydrogen crossed over from anode side is directly reacted with oxygen at cathode side. As a result of direct reaction, water is produced and it hydrates the membrane. Thus, the membrane is not dried completely due to the hydrogen crossover and its direct reaction with oxygen. In this study, hydrogen concentration at the cathode outlet was measured with the mass spectrometer under OCV condition when dry N2/H2, Air/H2 and Air/Air were supplied. Then, direct reaction rate and the amount of produced water were calculated. As a result, it was found that the operating temperature is a dominant parameter on direct reaction rate while the flow rate is negligible.
공급 기체의 유동 배열이 자가가습형 고분자전해질막 연료전지의 동적 성능에 미치는 영향
공임모(Im Mo Kong),정애리(Aeri Jung),김민수(Min Soo Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Operating proton exchange membrane fuel cells (PEMFCs) without external humidifier has many advantages such as system simplicity, reduced system volume and weight, and reduced blower power. For these reason, many researchers have attempted to operate PEMFCs with dry gases and have evaluated the effect of operating parameters including flow arrangements. However, most of them were only focused on the steady-state performance of the fuel cell. In this study, we evaluated the dynamic performance of the fuel cell after start-up with different flow arrangements of co-flow and counter flow. During the experiments, dry gases were supplied to the fuel cell. The results showed that the cell performance is recovered more quickly with the counter-flow arrangement. In addition, with counter-flow arrangement, the cell showed better steady-state performance.
차량용 연료전지에서 기체확산층을 통과하는 기체유동에 관한 연구
공임모(Im Mo Kong),백경돈(Kyung Don Baik),김민수(Min Soo Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
A gas diffusion layer (GDL) is one of the main components in PEMFCs for a vehicle. The first role of GDL is a transport medium. Reactant gases and produced water are transported through the GDL. The next role of GDL is a support structure for MEA. So, GDL is usually made of porous material and the reactant gas flows in two directions passing through the GDL. The first direction is channel to membrane (through-plane) and the second one is channel to channel (in-plane). Measurement of the gas permeability in two directions provides much more detailed information about GDL structure and transport behavior. However, gas permeability don’t mean actual flow rate in GDL. In this study, the ratios of actual gas flow rate of through and in-plane directions are investigated in a practical point of view. The result shows that actual gas flow rate of through-plane direction is higher than that of in-plane direction, although gas permeability of through-plane direction is lower than that of in-plane direction.
고분자 전해질막 연료전지의 저가습 운전을 위한 다층구조 기체확산층에 관한 연구
공임모(Im Mo Kong),김성일(Sung Il Kim),김동규(Dong kyu Kim),김민수(Min Soo Kim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
Downsizing system is very important issue in a fuel cell vehicle using polymer electrolyte membrane. Polymer electrolyte membrane must be hydrated properly to ensure high proton conductivity of the membrane. Mostly, external humidifying systems using membrane, bubbler, and injection are used to humidify reactant gas. However, these external humidifiers expand the volume, weight and complexity of a fuel cell system. In this study, multi-layer structured gas diffusion layer (GDL) is utilized to a fuel cell to enhance water retention capacity for low humidity operation. Multi-layer structured GDL forms small empty spaces and plays a role as a internal humidifying system. Using Multi-layer structured GDL, the performance of fuel cell are improved more than 10% compared to normal GDL under low humidity operating conditions.
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.
공기호흡형 연료전지에서 작동 온도가 시스템 성능에 미치는 영향
정애리(Aeri Jung),공임모(Im Mo Kong),김민수(Min Soo Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
In an air-breathing proton exchange membrane fuel cell system, water management is very important issue. Generally, flooding problem is occurred at low temperature condition. However, as operating temperature is increased, water is removed well by water evaporation and gas diffusion. Therefore, it can be expected that flooding is solved at higher temperature. In this study, effect of operating temperature on performance in an air-breathing proton exchange membrane fuel cell is examined. As a result, it is found that the performance of the system is improved until specific temperature as operating temperature increased. The reason for enhanced performance is found as effective water removal through the analytical approach for water contents in gas diffusion layers.
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.