• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권4호
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• pp.218-224
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• 2004

We present a miniature Direct Methanol Fuel Cell (micro-DMFC) using platinum sputtered microcolumn electrodes with a limited amount of fuel. We use the microcolumn electrode in order to improve the power density of the micro-DMFC that consists of two electrodes and polymer electrolyte. We also design the built-in fuel chamber in the anode for the portable electronics applications. We design and fabricate both microcolumn and planar electrodes, having an identical projective area of 5mm${\times}$5mm. The diffusion current density of the microcolumn electrode is 1.73 times higher than that of the planar electrode at electrode potential of 1.1V in the half-cell test. The micro-DMFC based on the microcolumn electrodes shows the maximum power of 10.8$\pm$7.54㎼(43.23$\pm$0.16㎼/$\textrm{cm}^2$) at the projective area of 5mm${\times}$5mm, while the planar electrode micro-DMFC shows the maximum power of 0.81$\pm$0.42㎼(3.24$\pm$1.68㎼/$\textrm{cm}^2$) at the same projective area. The micro-DMFC based on the microcolumn electrodes shows 13 times higher power density that the micro-DMFC based on the planar electrodes does.

• 한국안전학회지
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• 제29권4호
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• pp.34-41
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• 2014

The goal of this study is to investigate some crack behaviors which affect the crack propagation angle at the planar solid oxide fuel cell with cracks under the fabricating and operating temperature and analyze the stresses by 3 steps processing on the solid oxide fuel cell. Currently, there are lots of researches of the performance improvement for fuel cells, and also for the more powerful efficiency. However, the planar solid oxide fuel cell has demerits which the electrode materials have much brittle properties and the thermal condition during the operating process. It brings some problems which have lower reliability owing to the deformation and cracks from the thermal expansion differences between the electrolyte, cathode and anode electrodes. Especially the crack in the corner of the electrodes gives rise to the fracture and deterioration of the fuel cells. Thus it is important to evaluate the behavior of the cracks in the solid oxide fuel cell for the performance and safety operation. From the results, we showed the stress distributions from the cathode to the anode and the effects of the edge crack in the electrolyte and the slant crack in the anode. Futhermore the crack propagation angle was expected according to the crack length and slant angle and the variation of the stress intensity factors for the each fracture mode was shown.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.121-124
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• 2007

Stacks of solid oxide fuel cell under 1kW max power were designed on planar type employing anode supported cell and metallic interconnects. The stacks composed of 3-cells, 8-cells, and 16-cells were fabricated by using single cell purchased from Indec, sealant and interconnect prepared at RIST. In performance test of the final 16-cells stacks, OCV was recorded to be 16.7 V. Peak power and power density were 1 kW, 0.77 $W/cm^{2}$ at $820^{\circ}C$, respectively. In addition, the long term degradation rate of the power exhibited 2.25 % in 500 h at $750^{\circ}C$.

• 전기학회논문지
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• 제57권11호
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• pp.2086-2094
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• 2008

Finding a planar surface on 3D space is very important for efficient and safe operation of a mobile robot. In this paper, we propose a method using a plane detection cell (PDC) and iterative randomized Hough transform (IRHT) for finding the planar region from a 3D range image. First, the local planar region is detected by a PDC from the target area of the range image. Each plane is then segmented by analyzing the accumulated peaks from voting the local direction and position information of the local PDC in Hough space to reduce effect of noises and outliers and improve the efficiency of the HT. When segmenting each plane region, the IRHT repeatedly decreases the size of the planar region used for voting in the Hough parameter space in order to reduce the effect of noise and solve the local maxima problem in the parameter space. In general, range images have many planes of different normal directions. Hence, we first detected the largest plane region and then the remained region is again processed. Through this procedure, we can segment all planar regions of interest in the range image.

• 한국전산유체공학회지
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• 제15권1호
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• pp.31-36
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• 2010

In the present study, computations for flow fields inside the CDI unit cells with electrodes and spacers have been made to evaluate their performance. Three types of unit cells that include a planar type, a serpentine channel type, and a spiral wound type were considered and their flow characteristics were compared. From the computational results, it is found that the serpentine channel type has a large flow resistance and can not guarantee the outflow flux for industrial applications. On the other hand, the planar type can sustain a large enough outflow flux but it's efficiency is low for the electrode-use because of the non-uniform velocity distribution inside the cell and dead zones in every corner. Finally, The spiral wound type has not only a large outflow flux as much as the planar type has, but also a high efficiency for the electrode-use because of uniform velocity distribution. From this comparison, we can expect that the spiral wound type of CDI unit cell would have a high performance deionization capability.

• 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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• 제28권6호
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• pp.657-662
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• 2017

This paper presents the reversible electrolysis characteristics of a solid oxide fuel cell (SOFC) using a $10{\times}10cm^2$ anode supported planar cell with an active area of $81cm^2$. In this work, current-voltage characteristic test and reversible electrolysis cycle test were carried out sequentially for 2,114 hours at a furnace temperature of $700^{\circ}C$. The current-voltage characteristics for reversible electrolysis mode was measured at a current of ${\pm}26.7A$ under various $H_2O$ utilization conditions. The reversible electrolysis cycle was performed 50 times at a current of ${\pm}32.4A$. As a result, The performance degradation of SOEC mode was larger than that of SOFC mode.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1740-1745
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• 2004

A simplified resistor network model for electrical and mass transport in anode-supported planar solid oxide fuel cell (SOFC) was constructed in order to investigate the effect of interconnect rib geometry on the cell performance. For accurate potential calculation, activation and concentration over-potentials at the electrode/electrolyte interfaces were fully considered in this calculation. When contact resistance was not considered, the optimum interconnect rib length were calculated to be $0.1{\sim}0.2$ mm for 2 mm half unit cell for given operation conditions and properties. However, with realistic contact resistance, the interconnect rib length should be increased to provide larger contact area and thus to obtain better performance.

• 한국광학회지
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• 제31권1호
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• pp.37-44
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• 2020

본 연구에서는 기본적인 평면 태양 전지 구조에 1차원 주기를 가지는 에미터 전극 배치를 통해 광학 및 전기적 효율을 최적화하는 설계방법을 제안한다. 에미터 전극의 주기가 줄어들면 애퍼처 비율이 감소해 빛 흡수율이 줄어들어 태양 전지 성능 저하에 영향을 끼친다. 본 연구에서는 시뮬레이션을 통해 가장 간단한 평판형 태양 전지 구조 내에서 에미터 전극 배열의 최적안을 제시하였다. 광학적 측면에서 에미터 전극이 없이 광흡수층 전면에서의 광흡수를 하는 레퍼런스 소자와 성능이 유사한 조건을 도출했다. 그리고 광흡수 및 전기적 효율 측면을 모두 고려하여 가장 효과적인 전극 구조를 제안하였다. 본 연구 결과는 광전 변환으로 생성된 전하를 전극으로 가장 효율적으로 전달할 수 있는 구조를 제안함으로써, 대체 에너지원에서 큰 비중을 차지하고 있는 태양 전지의 활용성을 높이는데 기여할 것이다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.123.1-123.1
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• 2010

The solid oxide fuel cell (SOFC) has attracted great deal of attention due to its high electrical efficiency, high waste-heat utilization, fuel flexibility, and application versatility. However, SOFC technology is still not matured enough to fulfill the practical requirements for commercialization. Therefore, all the research and development activities are mainly focused on a development of practically viable SOFCs with higher performance and better reliability. We were successful in fabricating high-performance anode-supported unit cells by employing hierarchically controlled multi-layered electrodes for both structural reliability and high performance. In addition, a novel composite sealing gasket made it possible to achieve excellent sealing integrity even with considerable surface irregularities in a multi-cell planar arrayed stack.