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Cathode 산소 공급조건에서 고분자막 내구평가 프로토콜의 가습/건조 시간 변화의 영향
임대현 ( Daehyeon Lim ),오소형 ( Sohyeong Oh ),정성기 ( Sunggi Jung ),정지홍 ( Jihong Jeong ),박권필 ( Kwonpil Park ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.1
Since the durability evaluation for improving the durability of PEMFC polymer membranes is very important for the development of PEMFC, research and development of the polymer membrane durability evaluation protocol (AST) continues. Recently, DOE's polymer membrane chemical/mechanical durability evaluation AST was developed and applied to Nafion XL for review. In order to shorten the evaluation time, oxygen was used as a cathode gas instead of air, and it was finished in 144 hours. Since DOE AST has a large number of voltage changes with 45 seconds of humidification and 30 seconds of drying, the degradation of the electrode has more influence on the MEA durability. Therefore, one cycle time was lengthened with 60sec of wet/300sec of dry, and the drying time was made longer than the humidification time to further deteriorate the polymer membrane, and it was finished in 240 hours. It was confirmed that the DOE AST for evaluation of the durability of the polymer membrane was accompanied by electrode degradation.
화학적/기계적 열화 병행방법에 의한 PEMFC 고분자막 내구성 평가
임대현 ( Daehyeon Lim ),오소형 ( Sohyeong Oh ),정성기 ( Sunggi Jung ),정지홍 ( Jihong Jeong ),박권필 ( Kwonpil Park ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.3
In order to improve the PEMFC (Proton Exchange Membrane Fuel Cell) durability, it is important to accurately evaluate the durability of the membrane in a short time. Recently, DOE (Department of Energy) reported a protocol that combines the chemical and mechanical durability of membranes to evaluate them effectively. This protocol applies chemical/mechanical deterioration to the membrane by repeating wet/dry while OCV (Open Circuit Voltage) holding. The problem of this protocol is that it is highly affected by electrode degradation due to change cycles in OCV and that the evaluation time is long. By using oxygen instead of air as the cathode gas while leaving the other conditions of the DOE protocol as it is, the durability evaluation time could be reduced from 408 hours to 144 hours. By reducing the number of voltage change cycles to 1/3, the electrode degradation due to the voltage change cycle was reduced to 1/12 when oxygen was used compared to air at the end, thereby enabling more accurate evaluation of polymer membrane durability.
PEMFC Cathode 산소 조건에서 전극 촉매 내구성 평가
오소형 ( Sohyeong Oh ),임대현 ( Daehyeon Lim ),박권필 ( Kwonpil Park ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.1
In this study, we tried to develop a method of accelerated degradation of the electrode by simply using a electronic loader without using a potentiostat to evaluate the durability of the electrode catalyst. To this end, the durability of the electrode was evaluated by repeating the stepwise voltage change using the self-generated voltage by introducing oxygen without introducing nitrogen into the cathode. For accurate electrode durability evaluation, that is, in order not to deteriorate the polymer membrane, the high voltage was lowered to 0.9 V in stepwise voltage change and the relative humidity was 100% to suppress degradation of the polymer membrane due to radicals. After 30,000 cycles (50 hours) of voltage change, the electrode active area decreased by 41.4%. It was confirmed that the electrode was deteriorated, but the polymer membrane was not deteriorated, that there was no increase in hydrogen permeability, no decrease in membrane thickness, and no increase in HFR(High Frequency Resistance).
서진이(Jinny Seo),임대현(Daehyeon Lim),정혜순(Hyesoon Jeong) 한국인터넷전자상거래학회 2003 인터넷전자상거래연구 Vol.3 No.1
온라인 기술시장은 단순한 기술 수요자와 공급자가 만나는 자리 뿐만 아니라 기술의 거래에 관련되는 절차와 그에 필요한 금융, 법률, 기술의 평가에 대한 정보를 제공함으로써 기술의 거래에 있어서 그 시간적, 물리적 비용을 줄이는데 그 존재의 이유가 있다 하겠다.<br/> 그러나 현재 기술시장은 온라인 뿐만 아니라 오프라인에서도 시장이 활성화되어 있지 못한 상태로 온라인 기술시장을 통한 정보의 확산 및 시장의 분위기 조성등의 기반 구축이 더욱 필요한 상황이라 하겠다.<br/> 이에 본 연구에서는 현재 우리나라 온라인 기술이전 시장 현황을 살펴보고 그 상황과 문제점을 도출한 후 해외의 온라인 기술이전 시장의 현황을 비교하여 우리나라 온라인 기술이전시장에 적합한 운영방안을 마련하고자 한다.
오소형 ( Sohyeong Oh ),조원진 ( Wonjin Cho ),임대현 ( Daehyeon Lim ),유동근 ( Donggeun Yoo ),박권필 ( Kwonpil Park ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.3
The durability of the PEMFC stack for large commercial vehicles should be more than 5 times that for passenger vehicles. If the Chemical Accelerated Stress Test (AST) of PEMFC(Proton Exchange Membrane Fuel Cells) membrane for passenger cars is applied as it is for large commercial vehicles, there is a problem that the AST time becomes more than 2,500 hours. In order to shorten the AST time of DOE (Department of Energy), the chemical durability of the polymer membrane was evaluated using oxygen instead of air as a cathode gas. In this study, Nafion XL was used as a polymer membrane to evaluate accelerated durability under OCV, 90?, RH 30%, H<sub>2</sub>/(air or oxygen) conditions. Among the DOE membrane durability target criteria, the decrease rate of short resistance was the fastest. By using oxygen instead of air, the degradation rate of the polymer membrane was accelerated while being less affected by electrode deterioration, reducing the polymer membrane durability evaluation time to less than half.
PEMFC 고분자 막의 Short 저항 및 Shorting에 관한 연구
오소형 ( Sohyeong Oh ),권종혁 ( Jonghyeok Gwon ),임대현 ( Daehyeon Lim ),박권필 ( Kwonpil Park ) 한국화학공학회 2021 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.59 No.1
The shorting resistance (SR) of the PEMFC(Proton Exchange Membrane Fuel Cell) polymer membrane is an important indicator of the durability of the membrane. When SR decreases, shorting current (SC) increases, reducing durability and performance. When SR becomes less than about 0.1 kΩ?cm<sup>2</sup>, shorting occurs, the temperature rises rapidly, and MEA(Membrane Electrode Assembly) is burned to end stack operation. In order to prevent shorting, we need to control the SR, so the conditions affecting the SR were studied. There were differences in the SR measurement methods, and the SR measurement method, which improved the DOE(Department of Energy) and NEDO(New Energy and Industrial Technology Development Organization) method, was presented. It was confirmed that the SR decreases as the relative humidity, temperature and cell compression pressure increase. In the final stage of the accelerated durability evaluation process of the polymer membrane, SR rapidly decreased to less than 0.1 kΩ·cm<sup>2</sup>, and the hydrogen permeability became higher than 15 mA/cm<sup>2</sup>. After dismantling the MEA, SEM(Scanning Electron Microscope) analysis showed that a lot of platinum was distributed inside the membrane.