Papers by Keyword: PEM Fuel Cell

Abstract: The wide applicability of proton exchange membrane fuel cells (PEMFCs) is hindered by their dependency on the Nafion membrane as a state-of-the-art electrolyte. Nafion membranes can only operate at relatively low temperatures, up to 80°C. Therefore, any application of the fuel cell above this temperature would cause the PEMFC to lose its proton conductivity and mechanical integrity. For this reason, the development of Nafion-free membranes for PEMFCs has been studied extensively through the corporation of several additives over polymer substrates. The charge transfer abilities of metal-organic frameworks (MOFs), among other properties, make them one of the possible additives. The objective of this work is to synthesize Nafion-free membranes based on graphene oxide, MOFs, ionic liquids, polyethylene glycol, and zirconium phosphate over PTTFE membrane as an alternative to Nafion membranes. The preliminary results gave proton conductivities in the range of 10^-4 S/cm up to 150°C with graphene oxide MOF addition to all samples.

Abstract: The polymer electrolyte membrane (PEM) fuel cells flow fields channels serve the same roles as nutrient and reactant circulation systems in plants and animals, so bio-inspired flow field channels with a similar could improve reactant uniform transport efficiency and boost fuel cell performance. In this analysis, the lung channel configuration of a humane lung and a tree leaf bio-inspired flow field channels are used as an anode and cathode bipolar plate. A channel model is developed for three new flow field patterns designs: leaf design, lung design and triple-serpentine. It has been observed that the performance improvement in terms of power in the bio-inspired flow field is 13.32% more than the triple serpentine. This indicates the bio-inspired design has good performance than other flow field design. Further a parametric steady is carried out experimentally to study the effect of cell operating temperature, anode and cathode humidity, hydrogen and oxygen flow rate on the cell performance.

Abstract: The Proton Exchange Membrane Fuel Cells (PEMFCs) performance is improved by flow field channel design. The flow field reactant distribution geometry on PEMFCs is primarily influenced by the perceived effect of pressure and transmission characteristics of reactant flow fields on the efficiency of fuel cells. Nutrients distributed in the biological branching structures systems found their optimum arrangement have more efficiently in each part. The flow fields design channels in polymer electrolyte membrane (PEM) fuel cells serve the same roles as nutrient transport systems in plants and animals, so bio-inspired flow fields design with a similar could maximize reactant transport efficiency and improve fuel cell performance. In this analysis, the lung channel design of a humane lung and a tree leaf bio-inspired flow field design is used for the flow fields of the anode and cathode bipolar plates. SOLIDWORKS produces a 3-D numerical CFD design for four new flow field pattern designs: leaf design, lung design, single-serpentine, and triple-serpentine. The model is simulated using ANSYS FLUENT-15.0 software to obtain pressure distributions in the flow field, concentration profiles of hydrogen on anode and oxygen on cathode channel, current flux density on the membrane, water concentration on the membrane, water generating in a cathode channel, the polarization curve and the power curve. It is observed that bio-inspired leaf and lung design performs better than serpentine flow field channels. So, leaf and lung design can be used in mopeds and automobiles to enhance electrical efficiency and at the same time reduce fuel consumption.

Abstract: In this study, the effects of cyclic voltammetry (CV) has been modeled with Rule-based mamdani-type fuzzy (RBMTF), by using experimental data for proton exchange membrane fuel cell with PVA/AG. In the system developed, RBMTF apply input parameters are CV, scan rate and time, output parameters are current density and voltage. 12300 values for experimental study also obtained with RBMTF. Membership functions (MFs) are the building blocks of fuzzy set theory, i.e., fuzziness in a fuzzy set is determined by its MF. Accordingly, the shapes of MFs are important for a particular problem since they effect on a fuzzy inference system. They may have different shapes like triangular, trapezoidal, Gaussian, etc. When the results obtained from RBMTF and statistical analyses of experimental data have been compared, it has been determined that the two groups of data are coherent, and that there is not a significant difference between them. As a result, this study indicates that RBMTF with different membership functions can be safely used for CV.

Abstract: A proton exchange membrane (PEM) fuel cell is an electrochemical device that directly converts chemical energy of hydrogen into electric energy.The structure of the flow channel is critical to the PEM fuel cell performance. In this paper, the effect of the cathode flow channel baffles on PEM fuel cell performance was investigated numerically. A three-dimensional model was established for the PEM fuel cell which consisted of bipolar plates with three serpentine flow channels, gas diffusion layers, catalyst layers and PEM. Baffles were added in the cathode flow channels to study the effect of the cathode flow channel baffle on the PEM fuel cell performance. And then, numerical simulation for the PEM fuel cell with various cathode channel baffle heights ranging from 0.2 mm to 0.6 mm was conducted.The simulated results show that there existed an optimal cathode flow channel baffle height in terms of the electrochemical performance as all other parameters of the PEM fuel cell were kept constant. It is found that the PEM fuel cell had the good electrochemical performance as the flow channel baffle heights was 0.4mm in this work.

Abstract: Liquid organic hydrogen carriers (LOHC) are a promising form to store hydrogen. However, the process of dehydrogenation has to be demonstrated for applications with proton exchange membrane (PEM) fuel cells which require very pure hydrogen. Here we document the measured degradation effects due to CO contamination on a PEM fuel cell that is supplied with hydrogen from a LOHC and we want to use later in a maritime application.

Abstract: Keywords: Thermal management; PEM fuel cell; Nanofluid Abstract. Tremendous need for an optimum conversion efficiency of a Polymer Exchange Membrane Fuel Cell (PEMFC) operation has triggered varieties of advancements namely on the thermal management engineering scope. Excellent heat dissipation is correlated to higher performance of a fuel cell thus increasing its conversion efficiency. This study reveals the potential advancement in thermal engineering of a fuel cell stack related to nanofluid technology. Nanofluids are seen as a potential evolution of nanotechnology hybridisation with fuel cell serving as a cooling medium. The thermophysical characteristics have been reviewed and challenges with regards to fuel cell application is discussed. Nanofluid has been successfully tested on many thermal management systems isolated from thermoelectrical environments such as fuel cell. The main challenge is formulating a nanofluid coolant with high thermal conductivity but with strict limit on electrical conductivity of less than 5 μS/cm. Lack of electrical conductivity data for various nanofluids in open literature is another challenge in nanofluid application in fuel cell.

Abstract: Both assembly force and temperature play an important role in the proton exchange membrane (PEM) fuel cell performance. In this paper, contact pressure between bipolar plate and gas diffusion layer (GDL) in a PEM fuel cell under various assembly forces and at different temperatures was studied numerically. Considering the coupling effects of assembly force and operating temperature on contact pressure, a three-dimensional finite element model of the PEM fuel cell was established and the contact pressure between the GDL and the bipolar plate was studied using commercial code ABAQUS. In order to verify the simulated results, the experimental study was conducted to investigate the contact pressure distribution between the bipolar plate and the GDL. The experimental results are in good agreement with the finite element method (FEM) results. The simulated and experimental results reveal that the contact pressure increased with the increase of assembly force and temperature. It is found that the contact pressure distribution between the bipolar plate and the GDL had the best uniformity under the applied torque of 3.0N·m and at the operating temperature of 80 °C in this work.

Abstract: Fuel cell operation with a dead-ended systems anode reduces fuel cell system cost, weight, and volume because the anode external humidification and recirculation hardware can be eliminated. However, water accumulation is one of the key factors which influence the stability of its performance. Generally, the anode flooding of PEMFC with anodic dead-end operating mode can be avoided by using periodic purge process. But such an operating method can lower the utilization efficiency of hydrogen because small amount of hydrogen is expelled out of fuel cell and wasted. In order to improve the utilization efficiency of hydrogen, the pulsating technique at anode has been proposed. In this paper, the investigation of the hydrogen pulsation effects for PEMFC stack has been made, with only continuous hydrogen supply, with between continuous hydrogen and pulsation hydrogen at different positions, such as the inlet or outlet of anode. The results shows that the performance of a PEMFC stack has been improved significantly when the pulsation hydrogen flow introduced from the outlet at anode.

Abstract: As fossil fuels are becoming less reliable and more costly, the Proton Exchange Membrane Fuel Cell (PEMFC) is emerging as the primary candidate to replace the stationary and transport applications. In this study numerical simulation on PEMFC is done by commercially available Computational Fluid Dynamics (CFD) software. A three-dimensional, model of a single PEM Fuel cell with serpentine flow field design has been used for the study. The numerical model is 3-D steady, incompressible, single phase and isothermal includes the governing of mass, momentum, energy, and species along with electrochemical equations. All of these equations are simultaneously solved in order to get current flux density and H₂, O₂ and H₂O fractions along the flow field design.