GOLD-PLATED TITANIUM VS CARBON-IMPLANTED TITANIUM AS MATERIAL FOR BIPOLAR PLATES IN PEM FUEL CELLS

2019 ◽  
Vol 26 (08) ◽  
pp. 1950038
Author(s):  
M. S. VLASKIN ◽  
A. V. GRIGORENKO ◽  
E. I. SHKOLNIKOV ◽  
A. S. ILYUKHIN
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Performance Enhancement ◽  
Precious Metals ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Electrical Performance ◽  
Carbon Ions ◽  
Bipolar Plates ◽  
Gold Plating

Three different types of current-collecting plates for air-hydrogen PEM fuel cell were manufactured and tested: unmodified titanium plates; gold-plated titanium plates and titanium plates treated by carbon ions implantation. It was shown that the applied surface modifications reduce contact resistance between titanium plate and carbon gas diffusion layer. Total ohmic resistance of fuel cell is reduced by 1.8 and 1.4 times in case of gold-plated titanium and carbon-implanted titanium, respectively, in comparison with uncoated titanium. Although gold plating turned out to be more profitable than carbon ion implantation in terms of electrical characteristics, in the last case, the performance enhancement was reached without using precious metals, which at mass production must play more important role. This technology promises to reduce the cost of bipolar plates manufacturing, while maintaining high electrical performance of PEM fuel cells.

scholarly journals Effective Technique for Improving Electrical Performance and Reliability of Fuel Cells

2017 ◽  
Vol 8 (4) ◽  
pp. 1868
Author(s):  
A. Albarbar ◽  
M. Alrweq
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Content ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Electrical Performance ◽  
And Performance

To optimise the electrical performance of proton exchange membrane (PEM) fuel cells, a number of factors have to be precisely monitored and controlled. Water content is one of those factors that has great impact on reliability, durability and performance of PEM fuel cells. The difficulty in controlling water content lies in the inability to determine correct level of water accumulated inside the fuel cell. In this paper, a model-based technique, implemented in COMSOL, is presented for monitoring water content in PEM fuel cells. The model predicts, in real time, water content taking account of other processes occurring in gas channels, across gas diffusion layers (GDL), electrodes, and catalyst layer (CL) and within the membrane to minimize voltage losses and performance degradation. The level of water generated is calculated as function of cell’s voltage and current. Model’s performance and accuracy are verified using a transparent 500 mW PEM fuel cell. Results show model predicted current and voltage curves are in good agreement with the experimental measurements. The unique feature of this model is that, no special requirements are needed as only current, and voltage of the PEM fuel cell were measured thus, is expected to pave the path for developing non-intrusive control and monitoring systems for fuel cells.

PVD Coated Bipolar Plates for PEM Fuel Cells

2005 ◽  
Vol 2 (4) ◽  
pp. 290-294 ◽  
Author(s):  
Shuo-Jen Lee ◽  
Ching-Han Huang ◽  
Yu-Pang Chen ◽  
Chen-Te Hsu
Keyword(s):  
Corrosion Resistance ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Physical Vapor Deposition ◽  
Corrosion Current ◽  
Pem Fuel Cells ◽  
Bipolar Plates ◽  
Coating Materials ◽  
Pvd Coating ◽  
Simulated Fuel

Aluminum was considered a good candidate material for bipolar plates of the polymer electrolyte membrane (PEM) fuel cells due to its low cost, light weight, high strength and good manufacturability. But there were problems of both chemical and electrochemical corrosions in the PEM fuel cell operating environment. The major goals of this research are to find proper physical vapor deposition (PVD) coating materials which would enhance surface properties by making significant improvements on corrosion resistance and electrical conductivity at a reasonable cost. Several coating materials had been studied to analyze their corrosion resistance improvement. The corrosion rates of all materials were tested in a simulated fuel cell environment. The linear polarization curve of electrochemical method measured by potentiostat instrument was employed to determine the corrosion current. Results of the corrosion tests indicated that all of the coating materials had good corrosion resistance and were stable in the simulated fuel cell environment. The conductivities of the coated layers were better and the resistances changed very little after the corrosion test. At last, single fuel cells were made by each PVD coating material. Fuel cell tests were conducted to determine their performance w.r.t. that was made of graphite. The results of fuel cell tests indicated that metallic bipolar plates with PVD coating could be used in PEM fuel cells.

Effect of Vibration on the Liquid Water Transport of PEM Fuel Cells

2009 ◽  
Author(s):  
Luis Breziner ◽  
Peter Strahs ◽  
Parsaoran Hutapea
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Transport ◽  
Liquid Water ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Sinusoidal Vibration ◽  
Fuel Cell Performance ◽  
Liquid Water Transport

The objective of this research is to analyze the effects of vibration on the performance of hydrogen PEM fuel cells. It has been reported that if the liquid water transport across the gas diffusion layer (GDL) changes, so does the overall cell performance. Since many fuel cells operate under a vibrating environment –as in the case of automotive applications, this may influence the liquid water concentration across the GDL at different current densities, affecting the overall fuel cell performance. The problem was developed in two main steps. First, the basis for an analytical model was established using current models for water transport in porous media. Then, a series of experiments were carried, monitoring the performance of the fuel cell for different parameters of oscillation. For sinusoidal vibration at 10, 20 and 50Hz (2 g of magnitude), a decrease in the fuel cell performance by 2.2%, 1.1% and 1.3% was recorded when compared to operation at no vibration respectively. For 5 g of magnitude, the fuel cell reported a drop of 5.8% at 50 Hz, whereas at 20 Hz the performance increased by 1.3%. Although more extensive experimentation is needed to identify a relationship between magnitude and frequency of vibration affecting the performance of the fuel cell as well as a throughout examination of the liquid water formation in the cathode, this study shows that sinusoidal vibration, overall, affects the performance of PEM fuel cells.

Fluorescence Microscopy for the Measurement of the Surface Properties of the Gas Diffusion Layers of Fuel

2010 ◽  
Author(s):  
Brooks Friess ◽  
Mina Hoorfar
Keyword(s):  
Water Management ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Fluorescence Microscopy ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Experimental Methodology ◽  
Test Fluid ◽  
Average Height ◽  
Wetted Area

One of the major problems of current proton exchange membrane (PEM) fuel cells is water management. The gas diffusion layer (GDL) of the fuel cell plays an important role in water management since humidification and water removal are both achieved through the GDL. Various numerical models developed to illustrate the multiphase flow and transport in the fuel cell require the accurate measurement of the GDL properties (wettability and surface energy). In a recent study, the capillary penetration technique has been used to measure indirectly the wettability of the GDL based on the experimental height penetration of the sample liquid into the porous sample. In essence, a high resolution microscope/camera was used to detect the rate of penetrated height into the sample GDL. The shortcoming of this type of visualization is that it can only be used for thin hydrophilic GDL samples with zero Teflon loadings. For the thick and high Teflon loading GDLs, there is not enough contrast to detect the height of the penetrated liquid. In the real fuel cells, the GDLs are made of the micro-porous and macro-porous layers with an optimum Teflon loading. Therefore, it is required to develop a new experimental methodology capable of detecting the rate of penetration and as a result the wettability of GDLs samples used in fuel cells. In this paper, the fluorescence microscopy technique is integrated into the experimental setup of the capillary penetration method to improve the contrast between the wetted and non-wetted area. The fluorescence setup uses a powder die, dissolved in the test fluid, which is excited by a concentrated ultraviolet light illuminated in the vertical manner. To acquire the profile images of the penetrated liquid, an optical mirror was used. This new setup has the added advantage of providing a visual representation of the different regimes of penetration (e.g., the fingering effect reported for the pathways of the liquid penetrated into the GDLs) that are defined by the capillary number and mobility ratio of each fluid. Since the GDL samples used in this study are relatively hydrophobic (e.g., with 40% Teflon loadings), the pattern of liquid penetration is not uniform. Thus, an image analysis program was developed to determine the average height of penetration based on the area under the entire wetted area. The general Washburn equation was then used to fit the extracted height data and provide the average internal contact angle for each test liquid.

Alloys that form conductive and passivating oxides for proton exchange membrane fuel cell bipolar plates

2004 ◽  
Vol 19 (6) ◽  
pp. 1723-1729 ◽  
Author(s):  
Neil Aukland ◽  
Abdellah Boudina ◽  
David S. Eddy ◽  
Joseph V. Mantese ◽  
Margarita P. Thompson ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Oxide Films ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Bipolar Plates ◽  
Concentrated Solutions ◽  
Exchange Membrane

During the operation of proton exchange membrane (PEM) fuel cells, a high-resistance oxide is often formed on the cathode surface of base metal bipolar plates. Over time, this corrosion mechanism leads to a drop in fuel cell efficiency and potentially to complete failure. To address this problem, we have developed alloys capable of forming oxides that are both conductive and chemically stable under PEM fuel cell operating conditions. Five alloys of titanium with tantalum or niobium were investigated. The oxides were formed on the alloys by cyclic voltammetry in solutions mimicking the cathode- and anode-side environment of a PEM fuel cell. The oxides of all tested alloys had lower surface resistance than the oxide of pure titanium. We also investigated the chemical durability of Ti–Nb and Ti–Ta alloys in more concentrated solutions beyond those typically found in PEM fuel cells. The oxide films formed on Ti–Nb and Ti–Ta alloys remained conductive and chemically stable in these concentrated solutions. The stability of the oxide films was evaluated; Ti alloys having 3% Ta and Nb were identified as potential candidates for bipolar plate materials.

On the Use of Pressure-Loaded Blister Tests to Characterize the Strength and Durability of Proton Exchange Membranes

2009 ◽  
Vol 6 (3) ◽  
Author(s):  
David A. Dillard ◽  
Yongqiang Li ◽  
Jacob R. Grohs ◽  
Scott W. Case ◽  
Michael W. Ellis ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Cyclic Fatigue ◽  
Proton Exchange Membranes ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Biaxial Stress ◽  
Bipolar Plates ◽  
Dimensional Changes ◽  
Strength And Durability

The use of pressurized blister specimens to characterize the biaxial strength and durability of proton exchange membranes (PEMs) is proposed, simulating the biaxial stress states that are induced within constrained membranes of operating PEM fuel cells. PEM fuel cell stacks consist of layered structures containing the catalyzed PEMs that are surrounded by gas diffusion media and clamped between bipolar plates. The surfaces of the bipolar plates are typically grooved with flow channels to facilitate distribution of the reactant gases and water by-product. The channels are often on the order of a few millimeters across, leaving the sandwiched layers tightly constrained by the remaining lands of the bipolar plates, preventing in-plane strains. The hydrophilic PEMs expand and contract significantly as the internal humidity, and to a lesser extent, temperature varies during fuel cell operation. These dimensional changes induce a significant biaxial stress state within the confined membranes that are believed to contribute to pinhole formation and membrane failure. Pressurized blister tests offer a number of advantages for evaluating the biaxial strength to bursting or to detectable leaking. Results are presented for samples of three commercial membranes that were tested at 80°C and subjected to a pressure that was ramped to burst. The bursting pressures exhibit significant time dependence that is consistent with failure of viscoelastic materials. Rupture stresses, estimated with the classic Hencky’s solution for pressurized membranes in conjunction with a quasielastic estimation, are shown to be quite consistent for a range of blister diameters tested. The technique shows considerable promise not only for measuring biaxial burst strength but also for measuring constitutive properties, creep to rupture, and cyclic fatigue damage. Because the tests are easily amenable to leak detection, pressurized blister tests offer the potential for characterizing localized damage events that would not be detectable in more commonly used uniaxial strength tests. As such, this specimen configuration is expected to become a useful tool in characterizing mechanical integrity of proton exchange membranes.

A Feasibility Study of Ribbon Architecture for PEM Fuel Cells

2010 ◽  
Vol 7 (5) ◽  
Author(s):  
Daniel F. Walczyk ◽  
Jaskaran S. Sangra
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
High Volume ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Open Circuit ◽  
Membrane Electrode ◽  
Fixture Design ◽  
Design Development ◽  
Test Fixture

The feasibility of an alternative fuel cell architecture, called a ribbon membrane electrode assembly (MEA), is demonstrated for low-temperature polymer electrolyte membrane (PEM) fuel cells used in portable power applications by comparing it to a traditional bipolar “stack” architecture. A ribbon MEA consists of adjacent PEM cells sharing a common gas diffusion layer to allow for lateral electrical current flow and an integral gas-tight, conductive interconnect/seal, where adjacent cells meet to prevent reactant gas leakage. The resulting lateral arrangement of MEAs can be used to supply all MEAs simultaneously instead of individual bipolar plates with flow fields for a stack. A pair of two-cell ribbon MEAs, with and without an interconnect/seal, were designed, prototyped, and sealed by thermal pressing. The MEAs were clamped in a two-piece box fixture to provide reactant gases on the anode and cathode sides, hooked to a fuel cell (FC) test stand and yielded an open circuit voltage (OCV) of 1.43 V with an interconnect/seal and 0.6 V without. A two-cell bipolar stack PEMFC with identical MEA specifications had an OCV of 1.86 V. Polarization curves for the ribbon MEA with interconnect/seal showed the sensitivity of performance to clamping pressure and positioning of the copper current collectors. The ribbon MEA polarization curve was also shifted downward by 0.42 V as compared with that of the traditional stack, and suspected causes (e.g., gas leaking) are attributable to the nonoptimal test fixture design. Hence, the ribbon MEA architecture is shown to be feasible. Future work suggested includes improvements to the test fixture design, development of automated manufacturing capabilities for high volume production, and demonstration of a multicell (>2) ribbon MEA PEMFC design.

PEM Fuel Cell Bipolar Plate Reliability and Material Selection

2003 ◽  
Author(s):  
Michael J. Ajersch ◽  
Michael W. Fowler ◽  
Kunal Karan ◽  
Brant A. Peppley
Keyword(s):  
Fuel Cells ◽  
Life Cycle ◽  
Fuel Cell ◽  
Failure Modes ◽  
Material Selection ◽  
Pem Fuel Cell ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Cycle Performance ◽  
Bipolar Plates

The majority of the research on PEM fuel cells to date has been focused on assessing fuel cell behavior in the early stages of its life cycle. However, as widespread commercialization approaches, PEM fuel cells will be required to operate reliably for increasingly longer periods of time. It therefore also becomes equally important to characterize fuel cell performance at the end of its lifecycle. The reliability of a PEM fuel cell is dependent on the material properties, the manufacturing methods, and the design of its individual components. Among these components, the bipolar plates have received the least attention as a factor that may limit a fuel cell’s life cycle performance. Driven by the need for cost and weight reduction of fuel cell stacks, a significant amount of development work has been directed towards the development of new materials and designs for bipolar plates. Selection of an appropriate design and/or material for bipolar plates requires that reliability and durability data must be available, and that testing protocols appropriate and indicative of fuel cell operation be established. This paper provides a review fuel cell bipolar plate reliability and durability. Topics that will be addressed include bipolar plate functionality and design requirements, plate materials selection, plate failure modes. This is followed by a description of new bipolar plate reliability/durability test methods being developed at the CAMM Fuel Cell Research Group.

scholarly journals Use of Electrochemical Impedance Spectroscopy for the Evaluation of Performance of PEM Fuel Cells Based on Carbon Cloth Gas Diffusion Electrodes

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Saverio Latorrata ◽  
Renato Pelosato ◽  
Paola Gallo Stampino ◽  
Cinzia Cristiani ◽  
Giovanni Dotelli
Keyword(s):  
Fuel Cells ◽  
Electrochemical Impedance Spectroscopy ◽  
Fuel Cell ◽  
Impedance Spectroscopy ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Carbon Cloth ◽  
Gas Diffusion Electrodes

Polymer electrolyte membrane fuel cells (PEMFCs) have attracted great attention in the last two decades as valuable alternative energy generators because of their high efficiencies and low or null pollutant emissions. In the present work, two gas diffusion electrodes (GDEs) for PEMFCs were prepared by using an ink containing carbon-supported platinum in the catalytic phase which was sprayed onto a carbon cloth substrate. Two aerograph nozzles, with different sizes, were used. The prepared GDEs were assembled into a fuel cell lab prototype with commercial electrolyte and bipolar plates and tested alternately as anode and cathode. Polarization measurements and electrochemical impedance spectroscopy (EIS) were performed on the running hydrogen-fed PEMFC from open circuit voltage to high current density. Experimental impedance spectra were fitted with an equivalent circuit model by using ZView software which allowed to get crucial parameters for the evaluation of fuel cell performance, such as ohmic resistance, charge transfer, and mass transfer resistance, whose trends have been studied as a function of the applied current density.

Electrical Performance of PEM Fuel Cells With Different Gas Diffusion Layers

2011 ◽  
Vol 8 (4) ◽  
Author(s):  
P. Gallo Stampino ◽  
L. Omati ◽  
G. Dotelli
Keyword(s):  
Water Management ◽  
Fuel Cells ◽  
High Current Density ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Open Circuit ◽  
Electrical Performance ◽  
Carbon Paper ◽  
Carbon Cloth ◽  
Current Densities

The microporous layer (MPL) is a key component of polymer electrolyte membrane fuel cells (PEM-FCs), and it is in charge of the gas and water management at the electrode-gas diffusion layer (GDL) interfaces. A MPL was prepared and coated onto two different commercial GDLs: a carbon paper (woven-non-woven (WNW)) and a carbon cloth (CC). Electrical performances of the so-obtained gas diffusion media (GDM), i.e., GDL coated with the MPL, were investigated in single cell testing (steady-state polarization curves) using a Nafion® catalyst coated membrane with a platinum loading of 0.5 mg/cm2 both for the anode and the cathode. Moreover, in order to better understand the polarization phenomena during the running of the FC, impedance spectroscopy was carried out in galvanostatic mode at different current densities. In particular, the effect of the air relative humidity (RH 100%, 80%, and 60%) was investigated, while the hydrogen was fed always fully humidified (100%). The WNW substrate has demonstrated to be superior to CC in a vast range of current densities (from open circuit voltage to 0.8 A/cm2). However, at high current density, the WNW GDM has some problems in water management.

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