• 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.

• 전기학회논문지
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• 제62권1호
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• pp.105-108
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• 2013

To resolve global environmental problems, many automobile companies are making a great deal of effort to develop so-called green-cars. One of the solutions is an electric vehicle equipped with the PEMFC (Proton Exchange Membrane Fuel Cell) stack. However, the cost of the stack, at the moment, is still too high. This obstacle must be resolved for commercialized fuel cell cars. One of the reasons for high cost is a relatively large amount of Pt (platinum) in the membrane. In this paper, a method for reducing the Pt-loading is introduced. Furthermore, the durability of the stack will be important for a company to stay competitive in world markets (in the future). For this, the diagnosis of the stack must be conducted on-line. Some diagnosis methods as key technology are also introduced in this paper.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.87.1-87.1
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• 2011

The residential Fuel Cell system has high efficiency of 85% with transferring natural gas to electrical power and heat, directly and it is a friendly environmental new technology in that $CO_2$ emission can reduce 40% compared with conventional power generator and boiler. The residential fuel cell system consists of two main parts which have electrical and hot storage units. The electrical unit contains a fuel processor, a stack, an inverter, a control unit and balance of plant(BOP), and the cogeneration unit has heat exchanger, hot water tank, and auxiliaries. 5kW class fuel process was developed and tested from 2009, it was evaluated for long-term durability and reliability test including with improvement in optimal operation logic. Stack development was crried out through improvement of design and evaluation protocol. Development of system controller was successfully accomplished through strenuous efforts and original control logic was optimized in 5kW class PEMFC system. In addition, we have been focused on development of system process and assembly technology, which bring about excellent improvement of reliability of system. The 5kW class PEMFC system was operated under dynamic conditions for 1,000 hours and it showed a good performance of total efficiency and durability.

• 한국수소및신에너지학회논문집
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• 제35권4호
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• pp.370-376
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• 2024

Load variations reduce the lifespan of polymer electrolyte fuel cells (PEFCs). To analyze the impact of load variations on durability of PEFCs, two stacks were built and operated continuously for 400 hours, one under load variations and the other under constant current condition with the same energy output. Using the example model provided by Mathworks, we obtained load variation data for the experiments. The performance curves were measured every 100 hours and analyzed by current interruption method and electrochemical impedance spectroscopy. The degradation comparison shows a much larger decrease in performance under the load variation. The activation resistance, electrical resistance, and mass transfer resistance are all found to increase more.

• 한국수소및신에너지학회논문집
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• 제20권3호
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• pp.208-215
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• 2009

PEMFC stack power output is needed to be around 100 kW to meet the requirements of automotive application and scaling-up the active area of the stack cells will allow a higher power. In the case of scaling-up the active area of cells, it is difficult to obtain uniform in-plane internal conditions such as temperature, relative humidity and stoichiometry of the feed gas. These ununiformity with the location in the cell would affect both the performance and durability of the stack, so it is important to understand phenomena in the cell for improving them. In this study, the current density, electrochemical resistance and performance distribution measurement was performed to understand the ununiformity in a single cell using in-situ method; (1) Current Density Distribution (CDD) Device and (2) Segmented Cell Fixture. The influence of location of feed gas on the performance of a single cell was experimentally measured and discussed by using a segmented single cell which was composed of 8 compartments. The correlation between the location and performance in a single cell was discussed by these two tools and it was extended between the local characterization and the durability in a MEA by comparing the used cell with a fresh one. It was also studied in terms of electrochemistry by Electrochemical Impedance Spectroscopy.

• 한국세라믹학회지
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• 제44권8호
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• pp.407-411
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• 2007

A 3-cell stacked anode-supported solid oxide fuel cell was designed and fabricated to achieve a complete gas seal and the facile stacking of components. The stack was assembled with a unit cell with $10{\times}10cm^2$ area, and each cell was interconnected by a stainless steel 430 separator using a proprietary sealant sheet. The stack performance was examined at various gas flow rates of $H_2+3.5vol%\;H_2O$, and air at a fixed temperature of $800^{\circ}C$. No gas leakage was found from the sealing between cells and inter-connects within a measurement system in this research during a prolonged time of 500 h in operation. The test resulted in an open circuit voltage of 3.12 V, a peak power of 149 W, and a power density of $0.61W/cm^2$, while the long term durability of the power showed 19.1% degradation during the prolonged time of 500 h when tested at $800^{\circ}C$.

• 한국수소및신에너지학회논문집
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• 제25권3호
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• pp.271-279
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• 2014

A 25kW-class polymer electrolyte membrane (PEM) fuel cell system has been developed for the propulsion of a leisure boat. The fuel cell system was designed to satisfy various performance requirements, such as resistance to shock, stability under rolling and pitching oscillations, and durability under salinity condition, for its marine applications. Then, the major components including a 30kW-class PEM fuel cell stack, a DC-DC converter, a seawater cooling system, secondary battery packs, and balance of plants were developed for the fuel cell system. The PEM fuel cell stack employs a unique design structure called an anodic cascade-type stack design in which the anodic cells are divided into several blocks to maximize the fuel utilization without hydrogen recirculation devices. The performance evaluation results showed that the stack generated a maximum power of 31.0kW while maintaining a higher fuel utilization of 99.5% and an electrical efficiency of 56.1%. Combining the 30-kW stack with other components, the 25kW-class fuel cell system boat was fabricated for a leisure. As a result of testing, the fuel cell system reached an electrical efficiency of 48.0% at the maximum power of 25.6kW with stable operability. In the near future, two PEM fuel cell systems will be installed in a 20-m long leisure boat to supply electrical power up to 50kW for propelling the boat and for powering the auxiliary equipments.

• 멤브레인
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• 제33권3호
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• pp.127-136
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• 2023

본 연구에서는 실리카 복합막 기반 고분자 전해질막을 5단 연료전지 스택에 적용하여 성능 평가를 수행하였다. 이를 통하여, 개별 구성 요소의 성능도 중요하지만, 전체적인 관점에서 공급되는 연료의 유량이 스택 성능에 중요한 역할을 하며, 특히 수소의 유량에 크게 의존한다는 사실이 확인하였다. 산소의 유량을 증가시켜도 성능의 변화는 미미한 반면, 수소의 유량을 증가시키면 성능이 향상되는 것을 확인하였다. 그러나 수소의 유량 증가는 수소와 산소 유량 비율의 불균형을 초래하여 장기적으로는 스택 성능과 내구성을 저하시키는 문제가 관찰되었다. 이러한 현상을 스택 구성 요소 및 개별 단위 셀에서도 관찰할 수 있었으며, 따라서 스택 운전 시 각 구성 요소의 성능을 최적화하는 것 외에도 균일한 유량 제어를 위해 유로 설계 및 운전 조건을 최적화하는 것이 중요하다는 것을 알 수 있었다. 마지막으로 실리카 복합막은 최대 출력 기준 25 W 이상의 성능을 나타내어 실제 연료전지 시스템에 적용하기에 충분한 성능을 갖춘 것으로 판단된다.

• 한국수소및신에너지학회논문집
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• 제34권4호
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• pp.358-368
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• 2023

The fuel cell market is expected to grow rapidly. Therefore, it is necessary to scale up fuel cells for buildings, power generation, and ships. A multi-stack system can be an effective way to expand the capacity of a fuel cell. Multi-stack fuel cell systems are better than single-stack systems in terms of efficiency, reliability, durability and maintenance. In this research, we developed a residential fuel cell stack and system model that generates electricity using the fuel cell-photovoltaic hybrid system. The efficiency and hydrogen consumption of the fuel cell system were calculated according to the three proposed power distribution methods (equivalent, Daisy-chain, and optimal method). As a result, the optimal power distribution method increases the efficiency of the fuel cell system and reduces hydrogen consumption. The more frequently the multi-stack fuel cell system is exposed to lower power levels, the greater the effectiveness of the optimal power distribution method.

• 한국세라믹학회지
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• 제44권12호
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• pp.720-726
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• 2007

Current collectors of SOFC play a significant role on the performance of power generation. In this study a single cell stacked SOFC was assembled using Ag-mesh as a cathode current collector, and evaluated its performance. No gas leakages of the single cell stack occurred in the tests of gas detection and OCV measurement. The OCV and initial power of the stack were 1.09V and $0.45W/cm^2$, respectively, under the flow rates of air at 2,500 cc/min and $H_2$ at 1,000 cc/min at the test temperature of $750^{\circ}C$. A degradation rate of 44.0% was measured during the prolonged time of 307 h. The relatively low durability of the tested single cell stack was found to be the evaporation of Ag-mesh at the current corrector.