• 한국수소및신에너지학회논문집
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• 제6권2호
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• pp.53-63
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• 1995

차세대의 새로운 발전방식인 용융탄산염형 연료전지 시스템개발 사업중 실용 스택개발을 위하여 전극유효연적이 $100cm^2$ 인 단위전지를 10단 적층한 Cross Flow형 MCFC스택을 제작하고 2성능측정설비를 구성하여 장기운전시험을 실시하였다 연료로는 $H_2/CO_2/H_2O$의 비율을 72%/18%/10% 로 조성한 가스를 이용하고 산화제가스로는 $O_2/CO_2$ 및 $Air/CO_2$ 비율이 33%/67%, 70%/30%가 되는 가스를 이용하여 운전할때의 초기성능 및 15A($150mA/cm^2$) 정부하 상태에서의 장기운전시험시의 전압 강하율을 조사하였다. 운전시간 310시간이 경과된 후의 스택전압은 8.39V이었고 이때의 출력은 125.8W를 보여주었다. 한편 1845시간이 경과한후 공기를 산화제로 이용하는 경우 전압은 6.95V로서 출력 104W를 나타내고 있다. 초기성능치에 의한 에너지 변환효율은 이용율이 40%인 경우 29.65%이었고 80%로 증가하는 경우 약 51.5%가 된다. 1840시간의 경과한때 까지의 전압 강하율은 약 52.4mV/1000hr로서 이전의 스택보다는 전압강하율이 감소되고 있으며 스택의 성능 저하의 주요한 요인은 개회로 전압의 저하로 내부단락동에서 기인하는 것으로 여겨진다. 또한 장기운전사 스택내부에서의 단위전지 전압분포가 균일하지 않음을 알 수 있어 이에 대한 개선을 필요로 한다.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.68-75
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• 2010

The one of the major problems in the development of PEMFC was regarding to the assurance of sealing on stack. The failure on the sealing creates the problems of fuel leakage, mixing, internal combustion, damage on parts and can be a direct reason for the degrading the efficiency of fuel cell. This paper studies on the analytical approach for improving the contacting pressure distribution on the gasket at the evaluation on the sealing of fuel cell stack. So, the assembly analysis on multi layered fuel cell stack was performed. The research on the simplification of finite element model was performed for three dimensional analysis at the multi layered state. The improved contact pressure distribution was obtained through the case studies on gasket for better sealing. In addition, the number of the cell was determined for the effective analysis and the structural characteristics were evaluated based on this research.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.1-4
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• 2008

Fuel cells have the potential of providing several times higher energy storage densities than those possible using current state-of-the-art lithium-ion batteries, but current energy density of fuel cell system is not better than that of lithium-ion batteries. To achieve the high energy density, volume and weight of fuel cell system need to be reduced by miniaturizing system components such as stack, fuel tank, and balance-of-plant. In this paper, the thin flexible PCB (Printed circuit board) is used as a current collector to reduce the stack volume. Two end plates are made from light weight aluminum alloy plate. The plate surface is wholly oxidized through the anodizing treatment for electrical insulation. The opening rate of cathode plate hole is optimized through unit cell performance measurement of various opening rates. The performances are measured at room temperature and ambient pressure condition without any repulsive air supply. The active area of MEA is 10.08 $cm^2$ and active area per a unit cell is 1.68 $cm^2$. The peak power density is about 210 mW/$cm^2$ and the air-breathing planar stack of 2 Wis achieved as a small volume of 18 cc.

• 한국수소및신에너지학회논문집
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• 제27권1호
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• pp.42-48
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• 2016

This study presents an experiment investigation on natural convection heat transfer of air-cooling Proton exchange membrane fuel cells (PEMFCs) in a enclosure system for unmanned aerial vehicles (UAVs). Considered are replacing fuel cell stack with Aluminum block for heat generating inside a enclosure chamber. The volume ratio of fuel cell stack and chamber for simulation to the actual size of aerial vehicle is 1 to 15. The parameters considered for experimental study are the environmental temperature range from $25^{\circ}C$ to $-60^{\circ}C$ and the block heat input of 10 W, 20 W and 30 W. Effect of the thermal conductivity of the block and power level on heat transfer in the chamber are investigated. Experimental results illustrate the temperature rise at various locations inside the chamber as dependent upon heat input of fuel cell stack and environmental temperature. From the results, dimensionless correlation in natural convection was proposed with Nusselt number and Rayleigh number for designing air-cooling PEMFC powered high altitude long endurance (HALE) UAV.

• 조명전기설비학회논문지
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• 제27권8호
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• pp.51-59
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• 2013

High temperature fuel cell system, such as molten carbonate fuel cells(MCFC) and solid oxide fuel cells(SOFC), are capable of operating at MW rated power output. The power output change of high temperature fuel cell imposes the thermal and mechanical stresses on the fuel cell stack. To minimize the thermal-mechanical stresses on the stack, increases in the power output of high temperature fuel cell typically must be made at a slow rate. So, the short time interruption of high temperature fuel cell causes considerable generated energy losses. Because of the characteristic of high temperature fuel cell, we analyzed the impact of electrical fault in the fuel cell plant on other fuel cell generators in the same plant site. A various grounding configuration and voltage sag are analyzed. Finally, we presented the solution to minimize the effect of fault on other fuel cell generators.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.94-96
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• 1994

To develop the 2kw class MCFC stack, preliminarly 3 cell and 10 cell stack having a $100cm^2$ effective electrode area were fabricated and tested. These stacks showed 30 W and 100 W of output respectively and average cell voltage of 0.734V at $150mA/cm^2$. The stack performance decreased with the increase of fuel utilization rate. In durability test of 10 cell stack, the performance was sharply decreased at the rate of 180mV/1000Hr during 720hours operation time.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.460-465
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• 2003

The modeling of PEM (Proton Exchange Membrane) fuel cell system consisting of fuel cell stack and BOP (Balance of Plant) is presented in this paper. The effects of temperature, pressure (air, hydrogen), and humidity on the fuel cell system performance were mainly investigated using thermo-dynamical and electro-chemical equations. To understand the power distribution characteristics of fuel cell system, the effects of operating temperature and air pressure on maximum power and system power were also demonstrated. Through this study, we can get the basic insight into the fuel cell stack and BOP component sizing and it can be used effectively for the optimization of the practical fuel cell systems in purpose.

• 전자공학회지
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• 제30권1호
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• pp.43-49
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• 2003

이동 전자기기 혹은 이동 전원에 적용 가능한 휴대용 Fuel Cell에 필요한 재료는 놀은 전력을 요구하는 주택용이나 무공해 자동차용 및 대형발전 장비용 Fuel Cell과는 다르게 이해되어야 한다. 휴대용 Fuel Cell은 상온, 상압에서 작동되어야 하고 Fuel Cell의 효율을 높이기 위한 여러가지 주변 장치들이 제거 혹은 소형화 되어야 하므로, 이러한 열악한 조건에 적합한 재료의 개발이 필수적이다. 본 논문에서는 휴대용 Fuel Cell이 요구하는 촉매층, 확산전극, 수소이온 전도막 재료 및 Stack 혹은 Cell Pack의 개념에 대해 설명하고자 하며, 본 연구소에서 개발한 소형 PEMFC(MEA : 400㎽/㎠-무가습 수소/공기, 1 Bar, 30℃, Membrane: 0.1S/㎝; Stack : 40W)와 소형 DMFC (MEA : 50㎽/㎠-5M 메탄올 Passive, 상온 ; MEA : 100㎽/㎠ 2M 메탄올-Active, 1Bar, 상온 ; Membrane : Hybrid : Cell Pack : 2W)와 관련한 기술내용 및 상용화 전망에 대하여 언급하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.554-557
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• 2008

In this study, two types of central flow distributor designs are presented and compared to obtain the optimal compact design which has the least flow resistance and the uniform flow distribution in a vehicular fuel cell stack. For effective and reliable prediction on the thermo-flow characteristics of the reactants flow over the entire fuel cell stack domain, open channel flow in the bipolar plates of the power generating cells were simulated by applying a simplified flow resistance model with an empirical porous concept. A number of case studies were performed to figure out an optimal configuration of a central flow distributor device in terms of the time-dependent thermo-flow behavior and load-dependent flow distribution. The results showed that the stable and load-independent thermo-flow uniformity is very design specific, which is closely associated with the design of central manifolding devices in order to achieve the enhanced volumetric power density and the reliable long-lasting operating of fuel cells.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.197-200
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• 2007

FCEV uses electric energy generated from fuel cell stack, thus all consisting parts must be re-designed to be suitable for electricity based system. Cathode air blower which supplies compressed air into fuel cell stack has similar shape of turbocharger, but a radial turbine of traditional turbocharger is removed and high speed BLDC motor is installed . Generally, maximum 10% of electric power of fuel cell stack is consumed in air blower, therefore an effective design of air blower can improve the performance of FCEV directly. This study will present an aerodynamic design process of an air blower and compare computational results with experimental data.