scholarly journals Evaluating the Effect of Metal Bipolar Plate Coating on the Performance of Proton Exchange Membrane Fuel Cells

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3203 ◽  
Author(s):  
Oluwatosin Ijaodola ◽  
Emmanuel Ogungbemi ◽  
Fawwad Nisar. Khatib ◽  
Tabbi Wilberforce ◽  
Mohamad Ramadan ◽  
...  

Environmental concerns of greenhouse gases (GHG) effect from fossil commodities and the fast increase in global energy demand have created awareness on the need to replace fossil fuels with other sources of clean energy. PEM fuel cell (PEMFC) is a promising source of energy to replace fossil fuels. The commercialization of the cell depends on its price, weight and mechanical strength. Bipolar plates are among the main components of PEMFC which perform some significant functions in the fuel cell stack. Metal bipolar plate is considered by the research community as the future material for fuel cells. However, surface coating is required for metals to enhance its corrosion resistance, hydrophilicity and interfacial contact resistance (ICR) in PEM fuel cells. Open pore cellular metal foam (OPCMF) materials have been used to replace the conventional flow field channel in recent times due to its low electrical resistance, high specific area and high porosity; however, it endures the same corrosion problem as the metallic bipolar plate. This investigation offers an overview on different types of bipolar plates and techniques in coating metallic bipolar platse and open pore metal foam as flow field channel materials to improve the corrosion resistance which will eventually increase the efficiency of the fuel cell appreciably.

2018 ◽  
Vol 933 ◽  
pp. 342-350
Author(s):  
Yussed Awin ◽  
Nihad Dukhan

Bipolar plates in Proton Exchange Membrane fuel cells (PEMFC) distribute fuel and oxidant over the reactive sites of the membrane electrode assembly. In a stack, bipolar plates collect current, remove reaction products and manage water. They also separate neighboring cells and keep the oxidant and the fuel from mixing; they provide structural support to the stack. The plates are typically graphite with parallel or serpentine channels. The efficiency of a stack depends on the performance of the bipolar plates, which depends on the material and flow field design. The drawbacks of graphite include weight, fabrication inaccuracy, cost, porosity, and brittleness. Open-cell metal foam is investigated as a flow field/bipolar plate and compared to conventional graphite bipolar plates. The complex internal structure of the foam was modeled using an idealized unit cell based on a body center cube. This cell maintained the actual structural features of the foam. Clones of the idealized cell were virtually connected to each other to form the new bipolar plate. SolidWorks, and Auto-CAD were used to generate the unit cell and the computational domain, which was imported into ANSYS. Meshing of the domain produced than 350,000 elements, and 70,000 nodes. Appropriate boundary and operating conditions for PEMFC were applied, and the PEMFC module within ANSYS was used to obtain the temperature and flow distribution as well as the fuel cell performance. In comparison to conventional bipolar plates, results show that the cell current and voltage densities were improved, and temperature distribution on the membrane was even, and within the allowable limit. As importantly, there was a weight reduction of about 40% as a result of using metal foam as a bipolar plate.


2005 ◽  
Vol 2 (4) ◽  
pp. 290-294 ◽  
Author(s):  
Shuo-Jen Lee ◽  
Ching-Han Huang ◽  
Yu-Pang Chen ◽  
Chen-Te Hsu

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.


Author(s):  
Michael J. Ajersch ◽  
Michael W. Fowler ◽  
Kunal Karan ◽  
Brant A. Peppley

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.


2016 ◽  
Vol 30 (16) ◽  
pp. 1650155 ◽  
Author(s):  
Ebrahim Afshari ◽  
Masoud Ziaei-Rad ◽  
Nabi Jahantigh

In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.


Author(s):  
Michael Pien ◽  
Steven Lis ◽  
Radha Jalan ◽  
Marvin Warshay ◽  
Suresh Pahwa

Higher efficiency operation of PEM fuel cells needs an advanced passive way to remove product water. Water flooding in gas flow channels reduces efficiency and needs to be mitigated by a support of balance of plant design and components which results in parasitic power losses. ElectroChem’s Integrated Flow Field (IFF) design with the integration of hydrophobic and hydrophilic matrix has been proven to solve these challenges with no impact on the performance. The hydrophobic and hydrophilic matrix facilitates two phase (gas and liquid) flow to and away from the interface between the electrode membrane assembly and the flow field. A phase-separation feature of the IFF allowed the fuel cells to operate on a flow rate at its consumption rate. The IFF fuel cell has demonstrated operation at the ideal one stoichiometric ratio with 100% gas utilization and orientation independent. The IFF also served as gas humidifier through the creation of simultaneous distribution of gas and water within the cell. The self-humidification capability keeps the cell operating without the humidity of the input gas. The IFF design also enhanced the performance of water electrolysis which is a reverse process of fuel cell. The IFF supported the passive water feed to the cell and gas separation from the cell.


2004 ◽  
Vol 19 (6) ◽  
pp. 1723-1729 ◽  
Author(s):  
Neil Aukland ◽  
Abdellah Boudina ◽  
David S. Eddy ◽  
Joseph V. Mantese ◽  
Margarita P. Thompson ◽  
...  

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.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 471 ◽  
Author(s):  
Xuyang Zhang ◽  
Andrew Higier ◽  
Xu Zhang ◽  
Hongtan Liu

Flow field plays an important role in the performance of proton exchange membrane (PEM) fuel cells, such as transporting reactants and removing water products. Therefore, the performance of a PEM fuel cell can be improved by optimizing the flow field dimensions and designs. In this work, single serpentine flow fields with four different land widths are used in PEM fuel cells to study the effects of the land width. The gas diffusion layers are made of carbon cloth. Since different land widths may be most suitable for different reactant flow rates, three different inlet flow rates are studied for all the flow fields with four different land widths. The effects of land width and inlet flow rate on fuel cell performance are studied based on the polarization curves and power densities. Without considering the pumping power, the cell performance always increases with the decrease in the land width and the increase in the inlet flow rates. However, when taking into consideration the pumping power, the net power density reaches the maximum at different combinations of land widths and reactant flow rates at different cell potentials.


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