• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.82.2-82.2
• /
• 2010

The development of bipolar plate having high efficiency and chemical properties has a major impact on fuel cell applications commercialization. Even though graphite bipolar plate has high electric conductivity and chemical resistance, it has demerits about mass production and brittle property for commercialization. Hence, metallic bipolar plate can be substitute for fuel cell bipolar plate. Although its inadequate corrosion behavior under PEMFC environment lead to a deterioration of membrane by dissolved metal ions, metallic bipolar plate for PEMFC is more suitable for automotive and residential power generation system because of its high mechanical strength, low gas permeability and applicability to mass production. Therefore, several types of coating has been applied to prevent corrosion and oxide film growth and to achieve more high durability. This work presents durability of coated metal bipolar plate for low temperature PEMFC which made for fuel cell vehicle. This results showed surface treatment increase long-term durability, even electric conductivity and corrosion resistance.

• New & Renewable Energy
• /
• v.3 no.1 s.9
• /
• pp.75-82
• /
• 2007

Aluminum was used as metallic bipolar plate material to reduce a stack weight. The functional materials such as conductive material, Au and nonconductive material, PTFE [polytetrafluoroethylene] were coated on the bipolar plate to enhance electrical contact and corrosion prevention in PEMFC. The active area of bipolar plate is divided into the top layer part that electric current mainly passes, and the bottom layer part that gas and water pass. The bottom layer part in the flow channel needs not to have electrical conductivity because it doesn't pass electric current directly. In this reason, Au on the top layer and PTFE on the bottom layer were coated to apply high electrical conductivity and/or good corrosion resistance. Although the single cell performance using Au-PTFE/Al bipolar plate was shown 78% in comparison with that of graphite, specific power of Au-PTFE/Al bipolar plate(0.4 W/g) was twice as much as graphite bipolar plate.

• Journal of the Korean Society of Industry Convergence
• /
• v.21 no.4
• /
• pp.175-181
• /
• 2018

Stamping process and rubber pad forming process were performed to manufacture the bipolar plate for fuel cells. For that, a vacuum die casting process and a semi-solid forming process wherein liquid-state materials were used were adopted. After preparing the blank with the stainless steel thin plate having a thickness of 0.1 mm, the bipolar plate channel was formed with the stamping process and rubber pad forming process. The depth of the bipolar plate channel prepared by the stamping method was 0.45 mm and the depth of the bipolar plate channel prepared by the rubber pad forming process was 0.41 mm. Meanwhile, with the vacuum die casting and semi solid forming, the bipolar plate having a channel depth of 0.3 mm, same as the size of the die, could be formed.

• Transactions of Materials Processing
• /
• v.21 no.1
• /
• pp.5-12
• /
• 2012

The weight of the bipolar plate is one of the crucial aspects of improving power density in PEMFC stacks. Aluminum alloys have good mechanical properties such as density, electrical resistivity, and thermal conductivity. Furthermore, using aluminum in a bipolar plate instead of graphite reduces the bipolar plate cost and makes machining easier. Therefore in this study, an aluminum alloy was selected as the appropriate material for a bipolar plate. Results from feasibility experiments with the aim of developing fuel cells consisting of Al bipolar plates with multiple channels are presented. Dynamic loading was applied and the formability of micro channels was estimated as a function of punch pressure and die radius. Sheets of Al5052 with a thickness of 0.3mm were used. For a die radius of 0.1mm the formability was optimized with a sine wave dynamic load of 90kN at maximum pressure and 5 cycles of a sine wave punch travel. The experimental results demonstrate the feasibility of the proposed manufacturing technique for producing bipolar plates.

• Carbon letters
• /
• v.14 no.1
• /
• pp.40-44
• /
• 2013

The bipolar plate is the most important and most costly component of proton exchange membrane fuel cells. The development of a suitable low density bipolar plate is scientifically and technically challenging due to the need to maintain high electrical conductivity and mechanical properties. Here, bipolar plates were developed from different particle sizes of natural and expanded graphite with phenolic resin as a polymeric matrix. It was observed that the particle size of the reinforcement significantly influences the mechanical and electrical properties of a composite bipolar plate. The composite bipolar plate based on expanded graphite gives the desired mechanical and electrical properties as per the US Department of Energy target, with a bulk density of 1.55 $g.cm^{-3}$ as compared to that of ~1.87 $g.cm^{-3}$ for a composite plate based on natural graphite (NG). Although the bulk density of the expanded-graphite-based composite plate is ~20% less than that of the NG-based plate, the I-V performance of the expanded graphite plate is superior to that of the NG plate as a consequence of the higher conductivity. The expanded graphite plate can thus be used as an electromagnetic interference shielding material.

• Composites Research
• /
• v.34 no.6
• /
• pp.406-411
• /
• 2021

PEM (proton exchange membrane) fuel cells generate only water as a by-product, and thus are in the spotlight as an eco-friendly energy source. Among the various components composing the stack of the fuel cell, research on the bipolar plate that determines the efficiency of the fuel cell is being actively conducted. The composite bipolar plate has high strength, rigidity and corrosion resistance, but has the disadvantage of having a relatively low electrical conductivity. In this study, to overcome these shortcomings, a gas diffusion layer (GDL)-composite bipolar plate assembly was developed and its performance was experimentally verified. The graphite foil coating method developed in the previous study was applied to reduce the contact resistance between the bipolar plate and the GDL. In addition, in order to improve electron path in the stack and minimize the contact resistance between the GDL and the bipolar plate, a GDL-bipolar plate assembly was fabricated using a thin metal foil. As a result of the experiment, it was confirmed that the developed GDL-bipolar plate assembly had 98% lower electrical resistance compared to the conventional composite bipolar plate.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.6_1
• /
• pp.683-691
• /
• 2021

Bipolar plates with channel width of 0.5 mm, 0.4 mm, and 0.3 mm respectively were printed using a 3D printer. The shape of three b ipolar plates was rectangular, the channel depth was 0.5 mm, and the thickness of base was 0.5 mm. The bipolar plate with channel width of 0.5 mm had 45 channels, and their active area was 44.5 mm × 50 mm. The bipolar plate with channel width of 0.4 mm had 57 channels and its active area was 45.2 mm × 50 mm, and the bipolar plate with channel width of 0.3 mm had 75 channels and its active area was 44.7 mm × 50 mm. The bipolar plates were printed using PLA filament. The cross-sectional lengths of the bipolar plates with channel widths of 0.5 mm and 0.4 mm were identical by 96% of the designed cross-sectional length. Whereas the bipolar plate with a channel length of 0.3 mm had a large difference of 25% from the designed cross-sectional length.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.11
• /
• pp.3589-3592
• /
• 2012

Carbon composite bipolar plates with various carbon black contents were prepared by a compression molding method. The electrical conductivity and electrochemical stability of the bipolar plates have been evaluated. It is found that the electrical conductivity increases with increasing carbon black contents up to 15 wt %. When the carbon black contents are greater than 15 wt %, the electrical conductivity decreases because of a poor compatibility between epoxy resin and carbon black, and a weakening of compaction in the carbon composite bipolar plate. Based on the results, it could be concluded that there are optimum carbon black contents when preparing the carbon composite bipolar plate. Corrosion tests show that the carbon composite bipolar plate with 15 wt % carbon black exhibits better electrochemical stability than a graphite bipolar plate under a highly acidic condition. When the optimized carbon composite bipolar plate is applied to vanadium redox flow cells, the performance of flow cells with the carbon composite bipolar plate is comparable to that of flow cells with the graphite bipolar plate.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.144.2-144.2
• /
• 2010

Bipolar plate는 고분자 전해질 연료전지(PEMFC)에서 핵심 부품 중의 하나이고, 전해질 막이나 촉매 등에 비해서는 상대적으로 쉽게 접근할 수 있기 때문에 많은 연구가 수행되고 있다. Bipolar plate를 제조하는 기술은 크게 금속을 프레스 가공하는 방법, graphite 판을 직접 밀링하는 방법 및 고분자/카본계의 press molding 법 등 3가지로 분류되며, 본 연구에서는 3번째 방법에 의해서 bipolar plate를 대량 생산하는 방법에 대해 연구하였다. 고분자 매트릭스는 에폭시계 수지를 사용하였고, 카본계 재료는 graphite 분말과 carbon nanotube를 사용하였다. 이들 재료들을 일정한 비율로 혼합한 후 differential scanning calorimetry(DSC)를 사용하여 열분석 하였고, 그 결과를 Kissinger equation에 대입하여 경화반응 속도론을 연구하였다. 또한, 경화된 에폭시/탄소 복합재료의 전기전도도, 유리전이온도, 표면에너지 특성 등을 분석하였다.

• Corrosion Science and Technology
• /
• v.13 no.6
• /
• pp.224-232
• /
• 2014

Effect of pretreatments on the graphene coated bipolar plate of proton exchange membrane fuel cell(PEMFC) was investigated in simulated environments for PEMFC by using electrochemical measurement techniques. Interfacial contact resistance(ICR) between the graphene coated bipolar plate and the gas diffusion layer(GDL) was measured. The value of ICR decreased with an increase in compaction stress($20N/cm^2{\sim}220N/cm^2$). ICR of graphene coated bipolar plate was higher than that of bare 316L stainless steel. However, Potentiodynamic measurement results showed that the corrosion resistance of graphene coated bipolar plate was higher than that of bare 316L stainless steel. $H_2SO_4$ acid pretreatment was the most effective among various pretreatments. The lowest ICR and the corrosion current density were obtained when using $H_2SO_4$ solution pretreatment.