• 한국환경과학회지
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• 제5권4호
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• pp.535-544
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• 1996

In the development of Molten Carbonate Fuel Cell, one of the serious problems is the dissolution of cathode material. Therefore, the development of the alternative cathode which is stable in molten carbonate is needed. In this research, the licoo, was chosen as alternative cathode material. $LiCoO_2$ powder was synthesized by high temperature calcination method and by citrate sol-gel method. And its structure and physical iharacteristics were analyzed by XRD, 1 R, TCA and porosimeter. The conductivity and solubility of $LiCoO_2$ electrode were also measured. Homogeneous $LiCoO_2$ Powder was obtained by citrate sol-Rel method at 445$^{\circ}C$, however, obtained above 75$0^{\circ}C$ by high temperature calcination method. Homogeneous particle size distribution and fine powder were obtained by the citrate sol-Rel method. $LiCoO_2$ electrode showed higher electric conductivity ($1.7 $\Omega$^{-1}cm^{-1}$) than NiO (0.1 $\Omega$^{-9} cm^{-1}) at $650^{\circ}C$. The solubilities of $LiCoO_2$ electrode in electrolyte were varies 0.6 to 1.0 ppm during 200 hours. So, the solubilities of $LiCoO_2$ were much lower than that of NiO.

• 한국산학기술학회논문지
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• 제7권3호
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• pp.291-297
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• 2006

매우 작은 브릿지 형상을 무수히 지닌 용융탄산염 연료전지용 쉴드슬롯판이 생산 과정 중 일정한 곡률을 가지게 되는데, 자중으로 인해 본래의 곡률을 알 수 없게 되어 교정 작업에 지장을 초래한다. 본 연구에서는 이러한 쉴드슬롯판의 유효 물성치를 실험을 통하여 구하고, 이를 바탕으로 수치해석을 통해 쉴드슬롯판의 원래 곡률을 추정하였다. 구한 유효 물성치를 검증하기 위하여 정방향 및 역방향으로 놓인 쉴드슬롯판의 자중 처짐 형상을 계산을 통해 구하여 실험 결과와 비교하였다. 비교 결과 추정된 유효 물성치는 매우 타당하였고 이로부터 쉴드슬롯판의 원래 곡률을 추정할 수 있었다. 본 연구에서 추정된 유효 물성치는 추후 쉴드슬롯판의 편평도 향상에 대한 연구에서 유용한 자료로 활용될 수 있다.

• 신재생에너지
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• 제3권1호
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• pp.54-59
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• 2007

A sintering aid, $B_{2}O_{3}$ have been included into a $LiAlO_{2}$ electrolyte support by a tape casting method in order to reinforce mechanical strength of the support for molten carbonate fuel cells [MCFCs). Starting idea originates from the low melting point of $B_{2}O_{3}$ ($450^{\circ}C$), which can provide the low temperature consolidation of ceramic materials. The mechanical properties and the microstructure changes of the $B_{2}O_{3}$-included electrolyte support were examined by scanning electron microscope, mercury porosimetry, X-ray powder diffraction [XRD], high temperature differential scanning calorimeter and three-point bending strength measurement. The mechanical strength was clearly improved by addition of $B_{2}O_{3}$. The increase of mechanical strength results from the neck growth of a new $LiAlO_{2}$ phase between $LiAlO_{2}$ particles by the liquid phase sintering. Average pore size and porosity of the electrolyte support reinforced by addition of the sintering aid, $B_{2}O_{3}$, was $0.24{\mu}m$ and 59%, respectively which were suitable microstructure of a matrix for an application of MCFCs.

• 한국수소및신에너지학회논문집
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• 제18권4호
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• pp.406-412
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• 2007

An experimental study on the design of a catalytic combustor for 1.6 kW MCFC system has been performed. The roles of the catalytic combustor are to completely burn anode off-gas and to supply sufficient $CO_2$ to cathode channels. In order to avoid hot spot or fuel slippage, flow uniformity at the catalyst inlet was achieved by installing two crossing perforated plates between the catalyst and the mixing chamber with minimal pressure drop. A Pd/Ce/Ni-$Al_2O_3$ catalyst was used for complete combustion of the off-gas at GHSV=36,000.

• 소성∙가공
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• 제21권6호
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• pp.341-347
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• 2012

The metallic bipolar plates of the molten carbonate fuel cell(MCFC) are composed of shielded slot plates and a center-plate. The shielded slot plates support the center-plate and the membrane electrode assembly. Compressive forces are applied to the shielded slot plate in order to increase the contact area between shielded slot plates and the membrane electrode assembly (MEA). In the design of the shielded slot plate, it is necessary to predict the mechanical behavior of the shielded slot plate. The shielded slot plates are manufactured by a three-stage forming process consisting of slitting, preforming and the final forming process. The mechanical behavior of the shielded slot plate is largely affected by the forming process. In this study, the simulation of the three-stage forming process was used to predict the mechanical behavior of the shielded slot plate. The present simulation approach showed good agreements with the experimental results.

• 소성∙가공
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• 제21권5호
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• pp.298-304
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• 2012

The shielded slot plates for a molten carbonate fuel cell(MCFC) have a sheared corrugated trapezoidal pattern. In the FEM simulations for the production of the shielded slot plate, the user material subroutine VUMAT in the commercial FEM software ABAQUS was used to implement a ductile fracture criterion. The critical damage value for the ductile fracture criterion was determined by comparing the experimental results of the shearing process with the simulation results. Using the ductile fracture criterion, the FEM simulation of the three-dimensional forming process of the shielded slot plate was conducted. The effects of the shearing process on the forming process were examined through FEM simulation and experiments. The forming simulation of nine unit cells was conducted. Using the simulation results of the forming process, the deformed shape after springback was calculated. The experimental result shows good agreement with the simulation.

• 수산해양기술연구
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• 제27권2호
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• pp.125-131
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• 1991

Electrolyte matrix fabrication process can be classifed as hot pressing, tape casting, callendering, electrophoretic deposition. however, these have limits in practice. Hot pressing is cumbersome method, because of careful heating and cooling. Furthermore, the perfected tile is so fragile that it is difficult to fit in a cell. Therefore this method is not adequate for mass production of the electrolyte matrix. Using electrophoretic deposition method, a very thin matrix can be made, but many attempts of the electrolyte embeding were found to be failure. Tape casting and callendering methods are employed in most of the matrix fabrication for the present. But these methods require lots of water as a solvent, so that coating of the LiAlO sub(2) with electrolyte is difficult. Recently, hot roll milling method has been developed and the perfected matrix was proved to be free from crack. The method, however, needs a roller to make a matrix and a perfected matrix is carefully striped off from the cooled roller. Therefore, this method requires a long time due to the cooling process. The author proposes a cold rolling process. On this method, heated slurry of the LiAlO sub(2) mixed with binder, is rolled with a cold roller. The heated slurry dose not adhere to the roller, since contacted hot slurry is rapidly solidified. Therefore fabrication speed is increased, without getting rid of merits of the hot rolling process.

• 한국표면공학회지
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• 제40권3호
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• pp.149-158
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• 2007

Of all components of MCFC(molten carbonate fuel cell), corrosion of separator is one of the most decisive factor for commercializing of MCFC. In order to provide better understanding of corrosion behavior and morphology for gas channel of separator plate, post-analysis after cell operation for 1200 hours at $650^{\circ}C$ was performed by optical microscope, SEM and EPMA. Intergranular corrosion was observed on gas channel of separator plate. Corrosion product layer was identified as Fe-oxide, Cr-oxide and Ni-oxide by EPMA, and oxide thickness was measured with a $60{\mu}m-150{\mu}m$. Also, gas channel of separator was damaged by severe intergrannular attack with post analysis in consistent with immersion test. Moreover, pitting on the channel plate was observed with a depth of $18{\sim}24{\mu}m$. The results of immersion method are well agreement with post analysis measurements.

• 한국재료학회지
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• 제18권5호
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• pp.259-265
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• 2008

The corrosion and degradation factors of a current collector in a molten carbonate fuel cell (MCFC) were investigated to determine the optimized coating thickness of nickel on STS316L. The results show that the surface morphology and electrical properties depended on the nickel coating thickness. The surface morphology gradually changed from a flat to a porous structure along as the nickel coating thickness decreased, and the electrical resistance of the nickel-coated STS316L increased as the nickel coating thickness decreased. This can be attributed to the diffusion of elements of Fe and Cr from the substrate through the nickel grain boundaries. Additionally, carburization in the metal grains or grain boundaries in an anodic environment was found to influence the electrical properties due to matrix distortion. The resistance of Cr-oxide layers formed in an anodic environment causes a drop in the potential, resulting in a decrease in the system efficiency.

• 소성∙가공
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• 제20권4호
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• pp.273-278
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• 2011

Employing the TRIZ problem solving technique, a hybrid-type center plate for the molten carbonate fuel cell(MCFC) was developed for the purpose of improving gas sealing and maintenance. The manufacturing method of the hybrid-type center plate was divided into a trimming operation and a two-step bending process. In the latter, a modified punch shape was used to reduce springback. Using finite element(FE) simulations, bending stresses in the thickness and the in-plane directions were computed and the bending conditions were optimized. The optimized results of the two-step bending process were used as a basis for the design of the trimming process of the hybrid-type center plate. Finally, the external manifold-type center plate and the hybrid-type center plate were fabricated using a die set that accounts for the optimized conditions. It was found that the numerical simulation results were in good agreement with the experiments.