Fuel cells

2007 ◽  
Author(s):  
David Jollie
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Long Time ◽  
And Performance ◽  
The 1960S ◽  
Definition Of ◽  
Exchange Membrane

The vision of a world without oil or other fossil fuels is both surreal and at the same time seductive as a solution to current concerns over climate change and oil availability. It is also, to some extents, an irrelevant one for fuel cells. Rather than being an energy source they provide a mechanism for transforming one form of energy (chemical) to another (typically electricity or heat). In this way, they resemble batteries, internal combustion engines, and even steam engines. The key to their value is really their efficiency: they are able to carry out this transformation cleanly and efficiently. Fuel cells are not yet fully developed. The technology and the fuel cell effect were discovered in 1839 by, depending on your point of view, William Grove or Christian Schoenbein (Sanstede et al., 2003). For a long time after this, the technology was essentially dormant until the 1940s when Francis Bacon started working on it and the 1950s when Allis-Chalmers built the first application of the technology (a fuel cell powered tractor). Research and development accelerated when fuel cells were chosen as power sources for space missions in the 1960s and the 1970s oil price shocks increased interest in other technologies, but the real impetus came in the 1990s when DaimlerChrysler examined the proton exchange membrane fuel cell and decided that it could be used to power a vehicle. Considerable effort is still to be expended on improving fuel cell technology in terms of cost and performance. Ancillary questions like the best method of fuelling and of carrying fuel still remain to be solved. However, we have begun to see fuel cells entering the commercial marketplace and the coming years and decades should see this accelerate. A simple definition of a fuel cell might be ‘a device that reacts a fuel and an oxidant, without combustion, producing heat and electricity’. The best-known case, that of a proton exchange membrane (PEM) fuel cell (PEMFC), is illustrated in Fig. 11.1. In a PEM fuel cell, the fuel is hydrogen, the oxidant is oxygen and the only chemical product is water, as described in reaction (1): . . . 2H2 + O2 ⇒ 2H2O + heat + electricity (11.1) . . .

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.

Performance Studies on PEM Fuel Cell with 2, 3 and 4 Pass Serpentine Flow Field Designs

2014 ◽  
Vol 592-594 ◽  
pp. 1728-1732 ◽  
Author(s):  
M. Muthukumar ◽  
P. Karthikeyan ◽  
V. Lakshminarayanan ◽  
A.P. Senthil Kumar ◽  
M. Vairavel ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Flow Field ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Flow Parameters ◽  
Serpentine Flow Field ◽  
Performance Curves ◽  
And Performance ◽  
Exchange Membrane

The geometrical and flow parameters are governing the performance of the Proton Exchange Membrane Fuel Cell (PEMFC). The flow channels are used for distributing the reactants uniformly throughout the active area of fuel cell. Among different flow field designs, the serpentine flow field can give better performance to the PEM fuel cell. This paper numerically investigates the effects of the serpentine flow field with different number of passes. The 2 pass, 3 pass and 4 pass serpentine flow field designs of same rib size and channel size were modelled and analyzed using commercially available software package. From the polarization curves and performance curves drawn using the numerical results, the performance of three flow channel designs were compared and the maximum power densities of each design were found

MODELING OF PEM FUEL CELLS WITH FINITE-THICKNESS CATALYSTS

2009 ◽  
Vol 23 (03) ◽  
pp. 537-540 ◽  
Author(s):  
JIANG HUI YIN ◽  
JUN CAO
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Performance Optimization ◽  
Proton Exchange Membrane ◽  
Cell Model ◽  
Finite Thickness ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
And Performance ◽  
Exchange Membrane

A general proton exchange membrane fuel cell model including two finite-thickness catalysts is developed in this study, allowing for an in-depth understanding of the effects of the two key electrochemical reactions taking place in the two catalysts. The model is used to predict the performances of fuel cells employing two different flow channel designs, providing insights for fuel cell design and performance optimization.

scholarly journals Accelerated Lifetime Testing for Proton Exchange Membrane Fuel Cells Using Extremely High Temperature and Unusually High Load

2011 ◽  
Vol 8 (5) ◽  
Author(s):  
Jianlu Zhang ◽  
Chaojie Song ◽  
Jiujun Zhang
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
High Load ◽  
Proton Exchange ◽  
Accelerated Lifetime ◽  
Lifetime Testing ◽  
Exchange Membrane

In this paper, two testing protocols were developed in order to accelerate the lifetime testing of proton exchange membrane (PEM) fuel cells. The first protocol was to operate the fuel cell at extremely high temperatures, such as 300 °C, and the second was to operate the fuel cell at unusually high current densities, such as 2.0 A/cm2. A PEM fuel cell assembled with a PBI membrane-based MEA was designed and constructed to validate the first testing protocol. After several hours of high temperature operation, the degraded MEA and catalyst layers were analyzed using SEM, XRD, and TEM. A fuel cell assembled with a Nafion 211 membrane-based MEA was employed to validate the second protocol. The results obtained at high temperature and at high load demonstrated that operating a PEM fuel cell under certain extremely high-stress conditions could be used as methods for accelerated lifetime testing.

scholarly journals Optimal Estimation of Proton Exchange Membrane Fuel Cells Parameter Based on Coyote Optimization Algorithm

2021 ◽  
Vol 11 (5) ◽  
pp. 2052
Author(s):  
Amlak Abaza ◽  
Ragab A. El-Sehiemy ◽  
Karar Mahmoud ◽  
Matti Lehtonen ◽  
Mohamed M. F. Darwish
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Optimization Algorithm ◽  
Distribution Systems ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Exchange Membrane

In recent years, the penetration of fuel cells in distribution systems is significantly increased worldwide. The fuel cell is considered an electrochemical energy conversion component. It has the ability to convert chemical to electrical energies as well as heat. The proton exchange membrane (PEM) fuel cell uses hydrogen and oxygen as fuel. It is a low-temperature type that uses a noble metal catalyst, such as platinum, at reaction sites. The optimal modeling of PEM fuel cells improves the cell performance in different applications of the smart microgrid. Extracting the optimal parameters of the model can be achieved using an efficient optimization technique. In this line, this paper proposes a novel swarm-based algorithm called coyote optimization algorithm (COA) for finding the optimal parameter of PEM fuel cell as well as PEM stack. The sum of square deviation between measured voltages and the optimal estimated voltages obtained from the COA algorithm is minimized. Two practical PEM fuel cells including 250 W stack and Ned Stack PS6 are modeled to validate the capability of the proposed algorithm under different operating conditions. The effectiveness of the proposed COA is demonstrated through the comparison with four optimizers considering the same conditions. The final estimated results and statistical analysis show a significant accuracy of the proposed method. These results emphasize the ability of COA to estimate the parameters of the PEM fuel cell model more precisely.

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.

Development of a Space-Rated Proton Exchange Membrane Fuel Cell Powerplant

1999 ◽  
Author(s):  
William C. Hoffman ◽  
Arturo Vasquez ◽  
Scott M. Lazaroff ◽  
Michael G. Downey
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Potential System ◽  
Water Separator ◽  
Oxygen Gas ◽  
Product Water ◽  
Exchange Membrane

Abstract Power systems for human spacecraft have historically included fuel cells due to the superior energy density they offer over battery systems depending on mission length and power consumption. As space exploration focuses on the evolution of reusable spacecraft and also considers planetary exploration power system requirements, fuel cells continue to be a factor in the potential system solutions. Substantial efforts are currently underway in the commercial markets to produce a proton exchange membrane (PEM) fuel cell capable of meeting terrestrial power demands in residential, commercial, and automotive applications. However, there are unique characteristics of spaceflight that can only be dealt with through specific engineering solutions. From a systems perspective, removing product water from the cell stack and separating the water from the oxygen gas stream in a PEM fuel cell are two critical functions. One method to remove product water from the cell stack and subsequently separate the product water from the oxygen involves using components with no moving parts — a gas ejector and membrane gas-water separator. Tests are currently underway at the Johnson Space Center to evaluate and refine gas ejectors to satisfy the fuel cell requirement to circulate cathode reactant gas (oxygen) at 1 to 3 times the stoichiometric consumption flow rates in order to adequately remove water from the cathode. A gas-water separator utilizing hydrophobic and hydrophilic materials is also being evaluated to perform the function of separating the water from the oxygen gas stream. Analytical and experimental evaluations are continuing on the fuel cell components, including cell stacks, with the goal of developing a comprehensive design basis for a fuel cell powerplant capable of delivering 20 kW at approximately 28 VDC. Through the select critical component refinement in work at the Johnson Space Center, engineers are improving the readiness and reducing the technical and cost risks of a PEM fuel cell capable of operating in a space environment.

A Parametric Study of PEM Fuel Cell Performances

2002 ◽  
Author(s):  
Lin Wang ◽  
Attila Husar ◽  
Tianhong Zhou ◽  
Hongtan Liu
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Parametric Study ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Proton Exchange ◽  
Polarization Curves ◽  
Exchange Membrane

The effects of different parameters on the performances of proton exchange membrane fuel cells were studied experimentally. Experiments with different fuel cell temperatures, humidification temperatures and backpressures of reactant gases have been carried out. Polarization curves from experimental data are presented and the effects of the parameters on the performance of the PEM fuel cell are discussed. The experimental data obtained in this work are used to validate our 3-D mathematical model. It is found that modeling results agree well with our experimental data.

Degradation Effects on PEM Fuel Cells Supplied with Hydrogen from a LOHC System

2016 ◽  
Vol 839 ◽  
pp. 165-169 ◽  
Author(s):  
Thomas Luschtinetz ◽  
Andreas Sklarow ◽  
Johannes Gulden
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Pure Hydrogen ◽  
Exchange Membrane

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.

scholarly journals A Comprehensive Review on Measurement and Correlation Development of Capillary Pressure for Two-Phase Modeling of Proton Exchange Membrane Fuel Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Chao Si ◽  
Xiao-Dong Wang ◽  
Wei-Mon Yan ◽  
Tian-Hu Wang
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Capillary Pressure ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Porous Electrodes ◽  
Two Phase ◽  
Exchange Membrane

Water transport and the corresponding water management strategy in proton exchange membrane (PEM) fuel cells are quite critical for the improvement of the cell performance. Accuracy modeling of water transport in porous electrodes strongly depends on the appropriate constitutive relationship for capillary pressure which is referred to aspc-scorrelation, wherepcis the capillary pressure andsis the fraction of saturation in the pores. In the present PEM fuel cell two-phase models, the Leverett-Udellpc-scorrelation is widely utilized which is proposed based on fitting the experimental data for packed sands. However, the size and structure of pores for the commercial porous electrodes used in PEM fuel cells differ from those for the packed sands significantly. As a result, the Leverett-Udell correlation should be improper to characterize the two-phase transport in the porous electrodes. In the recent decade, many efforts were devoted to measuring the capillary pressure data and developing newpc-scorrelations. The objective of this review is to review the most significant developments in recent years concerning the capillary pressure measurements and the developedpc-scorrelations. It is expected that this review will be beneficial to develop the improved PEM fuel cell two-phase model.

Sign in / Sign up

Export Citation Format

Share Document