• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1177-1182
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• 2012

The corrosion resistance of 316L stainless steel coated with NiO-YSZ (Ni added yttria stabilized zirconia) was examined in a proton exchange membrane fuel cell (PEMFC) environment. The NiO-YSZ coating was carried out using a sol-gel dip coating method, and the corrosion resistance and interfacial contact resistance (ICR) were determined by the composition and morphology of the NiO-YSZ film. The corrosion resistance increased with increasing Ni content in the NiO-YSZ film, but rapid corrosion was observed when the YSZ film contained more than 15 wt % Ni due to surface cracks. The polarization resistance was improved by several orders of magnitude when 316L stainless steel was coated with a 15 wt % NiO-YSZ film compared to bare 316L. The ICR of the NiO-YSZ film was decreased to that of bare 316L when the YSZ film contained 25 wt % NiO, suggesting the possible application of NiO-YSZ coated stainless steel for a bipolar plate.

• 한국가스학회지
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• 제11권3호
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• pp.40-43
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• 2007

스택의 디자인과 운전조건을 최적화하여 PEMFC stack의 성능을 상당히 증진시킬수 있다. 그러한 결과로, 500시간의 DSS(Daily Start-up & Shutdown) 누적 운전후에 일별 운전성능은 조금의 편차가 있었지만 (0.02-0.9%), 스택의 성능은 거의 변화가 없음을 알 수 있었다. 따라서 PEMFC 시스템의 상용화를 위해서는 스택의 수명 및 운전의 신뢰성을 향상시켜야 한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.39-41
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• 2008

본 논문에서는 PEM(Proton Exchange Membrane) 연료전지 스택의 동적 특성에 관한 시뮬레이션에 대하여 기술한다. 연료전지의 출력은 부하 변동에 따른 가스 압력의 변화와 동작 온도의 변화 등에 민감하게 반응하는 특성을 갖고 있다. 본 논문에서는 부하 변화에 따른 스택 내부 채널의 가스 압력 변화를 계산하고 이를 Nernst 방정식에 적용하여 출력전압의 변동을 계산한 뒤 부하에 따른 손실을 계산하는 방법으로 동적 모델링을 수행하고 이를 이용한 시뮬레이션을 실시하였다. 스택의 각종 파리미터는 실험을 통해 추출되었고, 이를 적용한 Matlab/Simulink 시뮬레이션을 통해 제안된 모델이 연료전지 스택의 정특성 및 동특성을 적절하게 추종함을 확인하였다.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.57-68
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• 2016

In this study, we present the modern hybrid system based power generation for electric vehicle applications. We describe the hybrid structure of modified current source based DC - DC converters used to extract the maximum power from Photovoltaic (PV) and Fuel Cell system. Due to reduced dc-link capacitor requirement and higher reliability, the current source inverters (CSI) better compared to the voltage source based inverter. The novel control strategy includes Distributed Maximum Power Point Tracking (DMPPT) for photovoltaic (PV) and fuel cell power generation system. The proposed DC - DC converters have been analyzed in both buck and boost mode of operation under duty cycle 0.5>d, 0.5<d<1 and 0.5<d for capable electric vehicle applications. The proposed topology benefits include one common DC-AC inverter that interposes the generated power to supply the charge for the sharing of load in a system of hybrid supply with photovoltaic panels and fuel cell PEM. An improved control of Direct Torque and Flux Control (DTFC) based induction motor fed by current source converters for electric vehicle.In order to achieve better performance in terms of speed, power and miles per gallon for the expert, to accepting high regenerative braking current as well as persistent high dynamics driving performance is required. A simulation model for the hybrid power generation system based electric vehicle has been developed by using MATLAB/Simulink. The Direct Torque and Flux Control (DTFC) is planned using Xilinx ISE software tool in addition to a Modelsim 6.3 software tool that is used for simulation purposes. The FPGA based pulse generation is used to control the induction motor for electric vehicle applications. FPGA has been implemented, in order to verify the minimal error between the simulation results of MATLAB/Simulink and experimental results.

• 세라미스트
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• 제21권4호
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• pp.388-405
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• 2018

In this paper, we review about current development of electrode materials for Li-ion batteries and catalysts for fuel cells. We scrutinized various electrode materials for cathode and anode in Li-ion batteries, which include the materials currently being used in the industry and candidates with high energy density. While layered, spinel, olivine, and rock-salt type inorganic electrode materials were introduced as the cathode materials, the Li metal, graphite, Li-alloying metal, and oxide compound have been discussed for the application to the anode materials. In the development of fuel cell catalysts, the catalyst structures classified according to the catalyst composition and surface structure, such as Pt-based metal nanoparticles, non-Pt catalysts, and carbon-based materials, were discussed in detail. Moreover, various support materials used to maximize the active surface area of fuel cell catalysts were explained. New electrode materials and catalysts with both high electrochemical performance and stability can be developed based on the thorough understanding of earlier studied electrode materials and catalysts.

• 전기화학회지
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• 제12권1호
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• pp.61-67
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• 2009

Flow-field design has much influence over the performance of proton exchange membrane fuel cell (PEMFC) because it affects the pressure magnitude and distribution of the reactant gases. To obtain the pressure magnitude and distribution of reactant gases in five kinds of flow-field designs, computational fluid dynamics (CFD) analysis was performed. After the CFD analysis, a single cell test was carried out to obtain the performance values. As expected, the pressure differences due to different flow-field configurations were related to the PEMFC performance because the actual performance results showed the same tendency as the results of the CFD analysis. A large pressure drop resulted in high PEMFC performance. The single serpentine configuration gave the highest performance because of the high pressure difference magnitudes of the inlet/outlet. On the other hand, the parallel flow-field configuration gave the lowest performance because the pressure difference between inlet and outlet was the lowest.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.37-43
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• 2008

The durability test of turbo-blower for PEM fuel cell is very important process of BOP development. It is a major barrier to the commercialization of these systems for stationary and transportation power applications. Commercial viability depends on improving the durability of the air supply system to increase the reliability and to reduce the lifetime cost. In this study, turbo-blower supported by oil-free bearing is introduced as the air supply system used by 80kW proton exchange membrane fuel systems. The turbo-blower is a turbo machine which operates at high speed, so air foil bearings suit their purpose as bearing elements. The impeller of blower was adopted mixed type of centrifugal and axial. So, it has several advantages for variable operating condition. The turbo-blower test results show maximum parasitic power levels below 1.67kW with the 30,000 rpm rotating speed, the flow rate of air has maximum 163SCFM(@PR1.1). For proper application of FCV, these have to durability test. This paper describes the experiment for confirming endurance and stability of the turbo-blower for 500 hours.

• 멤브레인
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• 제17권4호
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• pp.311-317
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• 2007

Poly(vinyl alcohol-co-ethylene) (PVA-co-PE)와 poly(styrene sulfonic acid-co-maleic acid) (PSSA-co-PMA)을 고분자 블렌딩 방법으로 50 : 50의 무게비율로써 수소이온 전도성 가교형 전해질막을 제조하였다. PSSA와 PMA이 3 : 1과 1 : 1의 몰 구성비로 되이 있는 두 가지 종류의 PSSA-co-PMA 고분자를 수소이온 전도성 고분자로 사용하였으며, PVA-co-PE 고분자는 에틸렌의 함량이 0, 27 그리고 44 mol%인 고분자를 사용하였다. 전해질 막은 PVA의 히드록실 그룹과 PMA의 카르복시릭 그룹 사이의 에스테르화 반응을 통한 열가교를 통해 제조하였고, FT-IR을 통하여 이를 확인하였다. PSSA-co-PMA의 몰비율이 3 : 1로 구성되어 제조된 전해질막은 몰비율 1 : 1로 구성되어 제조된 막보다 더 낮은 이온교환용량과 더 높은 함수율, 수소이온 전도도를 나타내었다. 또한, 전해질막에서 PE의 함량이 증가할수록 이온교환용량, 함수율, 수소이온 전도도가 계속해서 감소하는 경향성을 보였다. 전해질막의 이러한 물성들은 술폰산기의 함량과 친수성, 막의 가교구조 사이의 경쟁적인 효과로써 설명하였다.

• Korean Chemical Engineering Research
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• 제56권1호
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• pp.1-5
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• 2018

본 연구에서는 고분자전해질 연료전지(PEMFC)가 실제 구동되는 고전류밀도 범위까지 임피던스를 분석해 이온전도도에 대해 연구하였다. 가스확산층(GDL)유무가 임피던스에 미치는 영향을 수소투과도 측정에 의해 간접적으로 검토하였다. 저전류 범위(<$80mA/cm^2$)에서 상대습도(RH)가 60% 이상 높을 때는 고분자 막의 수분 함량이 충분해 막의 이온전도도가 전류 변화의 영향을 받지 않았다. 그러나 RH가 낮을 때는 전류밀도가 증가하면서 수분 생성에 의해 이온전도도가 증가했다. 고전류 영역($100{\sim}800mA/cm^2$)에서 HFR (High Frequency Resistance)로 구한 막의 이온전도도 실험값과 수치해석에 의해 구한 값을 비교하였다. RH 100%에서는 실험값과 모사한 값 모두 전류 변화에 영향을 받지 않고 일정한 이온전도도를 유지함을 보였다. RH 30~70%에서는 전류밀도 증가에 따라 이온전도도가 증가하다 일정해 지는 경향을 나타냈다.

• 한국수소및신에너지학회논문집
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• 제19권6호
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• pp.498-504
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• 2008

Metal-reducing bacterium, Geobacter sulfurreducens is available for mediator-less microbial fuel cell (MFC) because it has biological nanowires(pili) which transfer electrons to outside the cell. In this study, in the anode chamber of the MFC system using G. sulfurreducens, the concentrations of NaCl, sodium phosphate and sodium bicarbonate as electrolytes were mainly optimized for the generation of electricity from acetate. 0.4%(w/v) NaClO and 0.5M $H_2SO_4$ could be utilized for the sterilization of acrylic plates and proton exchange membrane (major construction materials of the MFC reactor), respectively. When NaCl concentration in anode phosphate buffer increased from 5 to 50 mM, power density increased from 6 to $20\;mW/m^2$. However, with increasing sodium phosphate buffer concentration from 5 to 50 mM, power density significantly decreased from 18 to $1\;mW/m^2$. Twenty-four mM sodium bicarbonate did not affect electricity generation as well as pH under 50 mM phosphate buffer condition. Optimized anode chamber of MFC using G. sulfurreducens generated relatively high power density ($20\;mW/m^2$) with the maximum coulombic efficiency (41.3%).