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Polymer Electrolyte Membrane Fuel Cell (PEMFC) portable power generators are gaining importance in emergency applications. In this study, an air-cooled PEMFC stack was designed and fabricated for net 500 W power output. Gas Diffusion Electrodes (GDE's) were manufactured by ultrasonic spray coating technique. Stack design was based on electrochemica...
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... plates were bolted to end plates under specified pressure. When the all fixing plates were bolted and tightened, the pressure of hydraulic press was realised. Fig. 3i shows the final state of the PEMFC stack. The necessary gas, blower and voltage monitoring connectors were mounted on stack for the next step that was the performance tests of stack (Fig. ...
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... Fig. 3b shows the placement of current collector. After placing of first current collector by keeping Nafion laminated side contacting to end plate whilst the gold coated side were touching bipolar plate, the first bipolar plates were accom- modated as shown in Fig. 3c. The each bipolar plate was sealed with pre-cut gasket material before assembling of stack. The next steps of assembling were to accommodate MEA ' s and bipolar plates sequentially until placing of last bipolar plate as illustrated as in Fig. 3d and e. Fig. 3f shows the placement of second current collector. The second end plate was placed over the current collector and then pressed under hydraulic press as shown in Fig. 3h. The total replacement was obtained by hydraulic press and all external fixing plates were bolted to end plates under specified pressure. When the all fixing plates were bolted and tightened, the pressure of hydraulic press was realised. Fig. 3i shows the final state of the PEMFC stack. The necessary gas, blower and voltage monitoring connectors were mounted on stack for the next step that was the performance tests of stack (Fig. 4). Temperature profile inside the PEMFC is a very important parameter because a large variety of processes, such as kinetics of the electrochemical reactions, water condensation and diffusion, evaporation rate, and transport phenomena of reactant gases through the porous media, strongly depend on it. Moreover, it also directly affects the polymer of the membrane [23]. The heat generated in the stack is mainly produced in the cathode side of the cells by electrochemical reaction, or by irreversible processes that take place in the different elements due to ohmic or contact electric resistance. Furthermore, the way in which reactant gases are supplied to the cell can also affect the temperature profile of the device. Keeping the stack temperature at a desired level has a significant effect on safe and efficient operation of fuel cells. The generation of large amounts of heat results in an increase in the membrane resistance, which form hot spots in the membrane. Unless sufficient heat is removed, ...
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We present a novel membrane electrode assembly (MEA) fabrication method for proton exchange membrane water electrolysis (PEMWE). Inspired by previous work on PEM fuel cells (PEMFCs), we fabricated PEMWE-MEAs via direct membrane deposition (DMD). DMD-MEAs were fabricated by spray coating the membrane directly onto the cathode electrode-in this case,...
Proton exchange membrane (PEM) fuel cells operate with dead-ended anode in order to reduce system cost and complexity when compared with hydrogen re-circulation systems. In the first part of this work, we showed that localized fuel starvation events may occur, because of water and nitrogen accumulation in the anode side, which could be particularly...
Citations
... It can be produced from various renewable and nonrenewable sources, including hydro, wind, solar, biomass, geothermal, coal, natural gas, and nuclear [6]. Hydrogen fuel cells are an environmentally friendly technology that converts incoming hydrogen to electricity and contributes to producing renewable energy [7,8]. The system operates via a non-combustive electrochemical reaction between hydrogen and oxygen from the air, with water vapor as the resulting emission. ...
This paper precisely estimates the looming demand for hydrogen within the transportation sector, spanning 14 pivotal G20 nations from 2022 to 2050, anchored in the global vehicle hydrogen market penetration rate. Employing a robust techno-economic modeling methodology and leveraging Geographic Information System (GIS) for enriched visualization, it unveils distinct environmental dividends across three thoughtfully devised scenarios: Business-as-Usual, Moderate, and Aggressive. Findings herald India and China as pinnacles of hydrogen demand, with South Korea and Japan tailing closely. The study forecasts the energy consumption for solar hydrogen production in G20 countries to oscillate between 3.02 and 2.89 million GWh in 2022, while production costs are anticipated to range from $8.47/kg to $10.01/kg. In an assertive scenario, the paper illuminates a pathway towards achieving a significant CO2 reduction, unmasking environmental savings of up to a staggering 48%, equivalent to 1.5 million mtCO2, by 2050.
... In this study, therefore, a 100 kW FC is selected for the 4-passenger FCEV. The parasitic losses are taken into consideration during the design of PEMFC to account for energies consumed by supplementary equipments such as the pumps, the air compressor and the radiator fan [65,66]. Full load current density and voltage are taken as 0.4 A$cm À2 , and 0.68 V, respectively. ...
... Full load current density and voltage are taken as 0.4 A$cm À2 , and 0.68 V, respectively. 780 cm 2 active area PEMFC with the dead-end mode is selected, which offers the best hydrogen utilization rate with minimum auxiliary power consumption [65,67]. The operating temperature is fixed to 65 C, with a stoichiometric ratio of 1/3 for H 2 /air and with a 1.2 atm feeding pressure [65]. ...
... 780 cm 2 active area PEMFC with the dead-end mode is selected, which offers the best hydrogen utilization rate with minimum auxiliary power consumption [65,67]. The operating temperature is fixed to 65 C, with a stoichiometric ratio of 1/3 for H 2 /air and with a 1.2 atm feeding pressure [65]. ...
Using hydrogen fuel cell electric vehicles equipped with proton exchange membrane fuel cells could reduce greenhouse gas emissions from the transportation sector. Heating is necessary for a safe cold start-up process, but current methods consume a lot of electrical energy. In this research, it is proposed to heat the
hydrogen by using vortex tubes to separate the compressed hydrogen into a low and a high enthalpy streams and by using a heat exchanger to pump heat from the ambient into the cold stream. This system uses only the excess pressure available from the hydrogen tank as the motive power. A real gas thermodynamic model coupled with a genetic algorithm is used to maximize the hydrogen inlet temperature to the fuel cell for
three different configurations of vortex tubes and heat exchangers for a 4-passenger 100kW fuel cell electric vehicle while minimizing the heat exchanger conductance and area product. For hydrogen stored at -30oC , vortex tubes can increase the hydrogen feeding temperature from -1.6oC (Joule-Thompson heating in an isenthalpic throttling valve) to up to 18.3oC , which corresponds to a heating power of 622W.
... In air-cooled PEMFCs, the cathode side is directly connected to the environment, using ambient air as both coolant and oxidant. These are preferred power sources in specific applications like unmanned aerial vehicles (UAVs), portable electronics, and emergency power supplies [4][5][6][7][8]. This is due to their excellent traits, like low parasitic power and compact design [9]. ...
The choice of a suitable cathode flow field under varying ambient conditions (humidity and temperature) is essential for restraining mass transfer resistance and preventing localized overheating in air-cooled proton exchange membrane fuel cells (PEMFCs). To achieve this objective, this study recommends adopting a modified design that integrates tapered oblique fin (OF) channels into the ribs of the conventional parallel flow field. Subsequently, the superiorities of the modified design in terms of mass transfer capabilities and performance improvements under various ambient conditions are assessed compared to the conventional design through numerical analysis. The results show significant enhancements in mass transfer and cell performance with the modified design at higher humidity levels (e.g., 60 %-90 %). Besides, the modified design also achieves better performance in low air temperatures (e.g., 281.15 K-302.15 K). At an air temperature of 281.15 K, a maximum performance improvement of 9.34 % can be obtained. Air temperature and humidity both non-linearly affect current density distribution uniformity in the cathode CL. This is attributed to the complex interplay between water accumulation and oxygen transport under the ribs, coupled with convection phenomena within the OF channels. Moreover, the modified design more effectively enhances the temperature uniformity within porous electrodes at lower air temperatures.
... Although the 6 wt% objective can be reached, the tank volume is an issue. It has been possible to reach pressures of 70 MPa, and in 2002, Quantum Technology's 10,000 psi (68 MPa) Certification for on-board tanks was attained [30]. According to the office of technology policy report [31] [32], Toyota and Honda vehicles utilised hydrogen that was stored under high pressure and were available for lease in the latter part of 2002. ...
In recognition of the harmful effects of typical gasoline automobile emissions, the scientific community is turning to environmentally benign energy sources. Despite the abundance of renewable energy sources, hydrogen is the most effective one for use as automobile fuel. Like electricity, hydrogen is a powerful energy carrier capable of carrying large quantities of energy. The capacity of the vehicle's onboard hydrogen storage must be taken into account while developing fuel cell cars. This research looks at a recent advancement in hydrogen fuel cell engines to investigate the practicality of utilising hydrogen as a primary fuel in transportation systems, A fuel cell is an electrochemical device that produces energy by reacting chemical gases and oxidants. The fuel cell separates the cation and anion in the reactant in addition to using anodes to produce power. Reactants are compounds employed in fuel cells that cause a chemical reaction that results in the production of water as a byproduct. Hydrogen is one of the most efficient energy carriers, therefore the fuel cell can provide direct current (DC) electricity to run the electric car. A hydrogen fuel cell, batteries, and a control system along with methods can be used to make a responsible hybrid vehicle.
... Therefore, structurally, the number of bipolar plates also increases according to the number of MEA stacks. A sufficient number of MEA stacks is required for the high power output of the system (Devrim et al., 2015). That is, the weight of the entire system inevitably increases for high power output, and a significant portion of the weight is occupied by the weight of the bipolar plate. ...
The weight reduction of the bipolar plate (BP) is essential for commercializing unitized regenerative fuel cells (URFCs). In order to lighten the weight of the bipolar plate, we have used Pb/C composite powder as a cost-effective primary material, which is a mixture of low-density graphite and lead. Further, varied lead-carbon weight ratios (1: 8, 1:4, 1:1, 4:1, and 8:1) were investigated for fabricating the bipolar plate by hot-pressing process adding styrene-butadiene rubber (SBR) as a binder. The specific surface area, porosity, and microstructure characteristics corresponding to the varied lead-graphite ratio of the prepared bipolar plates were studied. The relative difference in conductivity upon the compressibility of the plates is also examined. Finally, the wettability and electrochemical properties of the prepared bipolar plates were evaluated through water contact angle and cyclic voltammetry analysis.
... Clamping pressure is an important parameter influencing PEMWE's performance and safety. Optimal performance is achieved when an even distribution of clamping pressure is applied across all BPPs; this can be achieved mechanically by using internal and external bolts i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( x x x x ) x x x or fixing plates [48,49]. Frensch et al. [48] investigated the influence of clamping pressure ranging from 0.77 MPa to 3.45 MPa at different temperatures and current ranges. ...
Hydrogen is the best energy vector for renewable and intermittent power sources. Electrolysis coupled with renewable energy resources is the most promising for the production of green hydrogen among the current hydrogen production methods. The polymer electrolyte membrane water electrolyzer (PEMWE) is the frontrunner of electrolyzer technology because of its ability to operate at high current densities and compact design, thereby enabling high-pressure operation. This review summarizes the static parameters (stack assembly and design aspects) and dynamic parameters (operating parameters and gas bubble removal) affecting PEMWE's performance, as well as static parameters (stack design) and dynamic parameters (operating parameters) affecting durability. For PEMWE, stack design plays an important role in the electrolyzer performance and durability, such as the fabrication of the bipolar plate and the material selection of the stack components. Recently, novel stack designs have shown promising performance and durability enhancements by lowering the ohmic and mass losses, enabling constant clamping pressure inside the stack, and eliminating the degradation of the BPP plates by using 3D-printed plastic plates, which also greatly lower the cost of the stack. Operating parameters, including temperature, pressure, and water flow rate, can be regulated during operation. However, temperature and pressure have a more significant impact on PEMWE's performance and durability than water flow rate. Research on magnetic fields, ultrasonic power, pulsed power, and pressure swings has shown promising results in increasing gas removal rate to enhance PEMWE's performance by addressing intrinsic mass transport limitations. However, their application to large PEMWE systems has not been extensively tested. Further studies are needed to elucidate their mechanism and potential in PEMWE applications.
... The catalyst layer (CL) is composed of carbon-based platinum or platinum alloy nanocatalysts (Pt/C) and the binder, which is typically Nafion, acts as an electrolyte in contributing to the electrochemical triple-phase boundary formation. Gas Diffusion Layer (GDL) is primarily composed of PTFEhydrophobic-based carbon paper or carbon-made fabric, via which reactant is carried into the Catalyst Layer (CL) and the product, in the form of water, is released on the cathode side [6][7]. In a bipolar plate, the current collector is a gas-impermeable carbon or steel plate covered with protective layers. ...
The PEM fuel cell was examined using numerical simulation in varied circumstances. To restore the fuel cell performance, a 3D-based PEMFC model was designed employing COMSOL Multiphysics 5.1. The analysis validity was confirmed using the V-I curves derived from data analysis in varied operational circumstances. The continuity, momentum, species transport and charge equations were used to represent the cell transport phenomenon. The flow of permeable medium in the gas diffusion layer was defined by employing Brinkman equations. V-I curves were obtained using the Butler-Volmer equations. According to findings, the current supply in the cathode catalyst layer achieves an optimum one, functioning as mass transport, ionic and charge transport resistances. It indicates optimum current supply in the cell holds a feature of highest oxygen deprivation on the channel's output side.
... PEM fuel cells are composed of a core membrane electrode assembly (MEA), bipolar plates, current collectors, and endplates [28]. MEA is a multi-layered structure that consists of a polymeric membrane, catalyst layers, and gas diffusion layers. ...
The most critical development in conventional underwater applications in recent years is to use hydrogen energy systems, including Air Independent Propulsion (AIP) systems. Proton Exchange Membrane (PEM) fuel cell-powered AIP systems increase interest worldwide. They offer many advantages such as longer endurance time without going to the surface for 2–3 weeks or without snorkeling with an average speed, perfectly silent operation, environmentally friendly process, high efficiency, and low thermal dissipation underwater. PEM fuel cells require a continuous source of hydrogen and oxygen as reactants to sustain a chemical reaction to produce electrical energy. Hydrogen storage is the critical challenge regarding the quality of supplied hydrogen, system weight, and volume. This paper reviewed hydrogen/oxygen storage preferences coupled with PEM Fuel Cell applications in the literature for unmanned underwater vehicles. Since underwater vehicles have different volume and weight requirements, no single hydrogen storage technique is the best for all underwater applications.
... J. Zhao et al integrated vapor chambers as heat spreaders into an air-cooled stack for thermal management improvement [15] and tested an air-cooled PEMFC stack with a dead-end anode to study the transient behavior at different step currents [16]. Y. Devrim et al designed and fabricated a 500 W air-cooled PEMFC stack with reaction area of 100 cm 2 for portable power generators and tested its performance [17]. F. Barreras et al studied the pressure drop of the forced air flow for the open cathode stack with a specifically designed measuring setup [18] and designed a 2 kW stack's cooling system with theoretical model predictions of electrochemical and heat behaviors [19]. ...
Proton exchange membrane fuel cell (PEMFC) is a promising electrical power source for the unmanned aerial vehicles (UAVs). In this paper, a novel kW-scale air-cooled PEMFC stack based on graphite plate is designed with 125 cm² reaction area for the UAVs applications. The extra edge channels of air cooling are designed for enhanced performance and lowered weight of the stack. Meanwhile, for optimized power system integration of the stack, the counter-cross and co-cross operations are compared in terms of performance and thermal behaviors. Validated by the 5-cell short stack tests, a 3D multi-physical model is developed to investigate the uniformity of local performance and thermal behaviors under various operating conditions. The results suggest that the counter-cross operation has better performance than that of the co-cross with enhanced uniformity of reaction current and water content distributions. The multiple-island shaped electrolyte current distribution patterns are observed while the local water content and temperature distributions accord with the cathode flow field structure. The thermal convection of the extra edge channels could enhance the stack performance with lowered membrane dehydration and uniformity of the temperature distributions. The findings of this work are beneficial for optimization of the stack design with relevant operation strategy.
... 13 New techniques are being sought to optimize performance by understanding the internal workings of these devices. 14 Recently, an air-cooled PEMFC stack with an active area of 100 cm 2 and 24 cells was designed by Devrim et al. 15 for a portable power generator. In this system, PEMFC stack temperature was monitored and automatically adjusted during the operation using a blower equipped with an electronic on-off control setup. ...
Air-cooled fuel cell systems feature a light-weight and simple design and are thus recognized as a suitable technology for drone and aviation applications. As compared to liquid-cooled fuel cell systems, however, they suffer from low specific power per unit volume and unstable performance due to severe electrolyte dehydration and nonuniform profiles of current density and temperature inside a fuel cell stack. Here, we present a high-pressure air-cooled fuel cell system in which atmospheric air is pre-compressed by a compressor and then fed into the fuel cell stack. To minimize the compressor power consumption, the system is designed to recirculate the exhaust air from the fuel cell stack. A three-dimensional two-phase fuel cell model is implemented with a high-pressure air-cooled fuel cell system mainly consisting of an air-cooled fuel cell stack, compressor, air chamber and duct, and heat exchanger and is used to predict superior fuel cell performances under various high-pressure conditions. Simulation results show that the fuel cell operation at 2 atm allows an increase of up to two times the stack power and 1.5 times the net system power compared to a 1-atm fuel cell operation.
