• 한국전기화학회:학술대회논문집
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• 2005.07a
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• pp.253-256
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• 2005

• Transactions of the Korean hydrogen and new energy society
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• v.32 no.4
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• pp.245-255
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• 2021

Various studies about metallic bipolar plates have been conducted to improve fuel cell performance through flow field design optimization. These research works have been mainly focused on fuel cells for vehicle, but not fuel cells for building. In order to reduce the price and volume of fuel cell stacks for building, it is necessary to apply a metallic flow field, In this study, for a metallic flow field applied to a fuel cell for building, the effect of a change in the flow field shape on the performance of a polymer electrolyte membrane fuel cell was confirmed using a model and experiments with a down-sizing single cell. As a result, the flow field using a metal foam outperforms the channel type flow field because it has higher internal differential pressure and higher reactants velocity in gas diffusion layer, resulting in higher water removal and higher oxygen concentration in the catalyst layer than the channel type flow field. This study is expected to contribute to providing basic data for selecting the optimal flow field for the full stack of polymer electrolyte membrane fuel cells for buildings.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.321-325
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• 2005

Bipolar plate is the main part with MEA in automotive PEMFC. It must have a good electrical conductivity and excellent corrosion resistance, be cost effective. Therefore, stainless steels have been studied by many researchers because of its corrosion resistance and cost benefits. But their properties are not sufficient for the application to bipolar plate for automotive PEMFC. In this work, we have performed stamping using various commercial stainless steels to select candidate material for biploar plate and to derive design parameters for stamping simulation. The results showed that a small curvature at the corner of flow field is more favorable due to easier a plastic deformation. Stamping process was simulated by changing surface condition, and the size and angle of channel. The optimum shape and spring back phenomena were evaluated. Surface coating was applied to increase the corrosion resistance and electrical conductivity of stainless steel. The electrical interfacial resistance was 10 to $15m{\Omega}cm^2$ under clamping force of 150psi. But corrosion resistance of coating on the stainless steel was not good due to the unstableness of microstructure.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.220-223
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• 2009

Metallic bipolar plate for molten carbonate fuel cell(MCFC) is composed of the shielded slot plate and the center plate. Among these, the center plate plays an important role in gas sealing. Therefore, manufacturing of the center plate is considered one of the key issues in MCFC. The center plate is manufactured by bending process. In bending process, springback and recoiling are two main problems. By using the modified punch shape with 'step', springback and recoil are reduced. The aim of this article is to find the effect of modified punch shape. So, the bending stress along thickness direction and material direction were investigated using FEM.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.19-20
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• 2014

연료전지 스택을 구성하는 핵심 부품 중 하나인 분리판(Bipolar plate)은 반응 연료인 수소와 산소를 분리하여 셀(cell)의 전면적에 균일하게 분배, 공급, 배기 및 전기화학반응에 의해 생성된 전류를 수집하며, 높은 가스밀폐성, 전기전도성 및 내식성이 요구된다. 분리판 소재로는 흑연, 고분자-탄소 복합체 및 금속 등이 사용되고 있으며, 이중 연료전지 스택의 부피, 무게 및 제조비용 감소를 위하여 금속분리판이 주목받고 있다. 그러나 금속분리판의 경우 연료전지 작동환경에서 부식반응에 의한 이온 용출로 인해 전극촉매나 고분자전해질막의 오염을 유발할 수 있다는 단점이 있어 최근 금속계 분리판의 코팅을 통하여 분리판의 내식특성 및 전기적 특성을 향상시키는 연구가 활발히 진행되고 있다.

• Journal of the Korean institute of surface engineering
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• v.48 no.3
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• pp.87-92
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• 2015

Carbon thin films were deposited on STS 316L sheets by inductively coupled plasma enhanced magnetron sputtering with or without substrate bias voltage. Typical Raman spectrum for amorphous diamond-like carbon (DLC) was obtained, and the interfacial contact resistance (ICR) was measured to show its conductive nature. The electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion mechanism of the carbon coating under the polymer electrolyte membrane fuel cell (PEMFC) condition. According to the pore-corrosion mechanism, the electrolyte penetrates the carbon coating through the pores and reacts with the substrate. As the substrate corrosion proceeds, the pore enlargement occurs and the surface area of the substrate exposed to the electrolyte. Applicability of the carbon coating for the PEMFC bipolar plate was evaluated by potentiodynamic polarization experiments. Finally, an adhesion problem was briefly considered.

• New & Renewable Energy
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• v.4 no.1
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• pp.31-36
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• 2008

Stainless steels have been widely considered as metallic bipolar plates, due to their passive surface film, which is good for corrosion resistance. However, the high resistivity of the passive film increases interfacial contact resistance between the bipolar plates and the electrodes. Stainless steels thermal spray coated with a mixture of tungsten carbide and stainless steel powders showed that the coated layer safely combined with the matrix but they suffered many internal defects including voids and cracks. Many cracks were formed in the coated layer and the interface of the matrix and the coated layer during the rolling process. The coated and rolled stainless steels showed lower interfacial contact resistance and corrosion resistance than bare stainless steel because of low resistivity of tungsten carbide and numerous defects, which caused crevice corrosion, in the coated layer.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.181-181
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• 2012

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.130.1-130.1
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• 2010

분리판(Bipolar plate)은 MEA 및 GDL의 구조적지지, 연료와 산화제를 공급해 주는 통로역할, 발생한 전류의 수집 및 전달, 그리고 반응 생성물의 수송 및 제거 등의 다양한 역할을 한다. PEMFC 및 DMFC의 분리판에 주로 사용되고 있는 재질은 Graphite 및 금속 물질이다. Graphite는 내부식성이 좋고 가벼워 현재 가장 많이 사용되고 있지만, 가공이 어렵고 깨질 위험이 있으며 두껍고 비교적 값이 비싸다. 금속은 가공성이 좋고 높은 전기 전도도를 가지며 가격이 저렴한 반면, 내부식성이 좋지 않은 단점이 있다. 연료전지를 실용화하는데 있어 중요한 문제 중 하나는 전지 성능의 수명과 경제성이며, 위와 같은 Graphite와 금속의 특성으로 인하여, Graphite 분리판을 금속 분리판으로 대체하기 위한 연구가 활발히 진행되고 있다. 본 연구에서는 원가절감을 위한 대량생산공정 중 하나인 염욕질화공정의 도입 및 적용을 위한 목적으로, 다양한 처리조건에 의해서 금속 표면을 처리하였으며, 표면처리된 금속은 부식특성, 접촉저항, 및 내구성 등을 평가하고 이를 통하여 금속계 분리판 적용성에 대해 알아보고자 한다.

• Corrosion Science and Technology
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• v.12 no.4
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• pp.171-178
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• 2013

In a polymer membrane fuel cell stack, the bipolar plate is a key element because it accounts for over 50% of total costs of the stack. In order to lower the cost of bipolar plates, 316L stainless steels coated with nitrides such as TiN and CrN by physical vapor deposition were investigated as alternative materials for the replacement of traditional brittle graphite bipolar-plates. For this purpose, interfacial contact resistances were measured and electrochemical corrosion tests were conducted. The results showed that although both TiN and CrN coatings decreased the interfacial contact resistances to less than $10m{\Omega}{\cdot}cm^2$, they did not significantly improve the corrosion resistance in simulated polymer electrolyte membrane fuel cell environments. A CrN coating on 316L stainless steel showed better corrosion resistance than a TiN coating did, indicating the possibility of using modified CrN coated metallic bipolar plates to replace graphite bipolar plates.