Water Balance in PEM Fuel Cells

2002 ◽  
Author(s):  
Michael G. Izenson ◽  
Roger W. Hill
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Balance ◽  
Power Systems ◽  
Direct Methanol Fuel Cells ◽  
Pem Fuel Cells ◽  
Electrochemical Characteristics ◽  
Water Production ◽  
Water Losses ◽  
Power Sources

Fuel cells based on polymer electrolyte membranes (PEMs) are attractive power sources because they are efficient, non-polluting, and do not rely on non-renewable fossil fuels. Water management is a critical design issue for these fuel cells because the PEM must be maintained at the proper water content to remain ionically conducting without flooding the electrodes. Furthermore, portable PEM power systems should operate at water balance. That is, water losses from the cell should be balanced by the rate of water production from the fuel cell reaction. A portable system that operates at water balance does not require an external supply of water. The rate of water production depends on the cell’s electrochemical characteristics. The rate of water loss depends on the flow rates of reactants and products, transport of water and fuel across the PEM, and the stack operating temperature. This paper presents the basic design relationships that govern water balance in a PEM fuel cell. Specific calculations are presented based on data from hydrogen/air and direct methanol fuel cells currently under development for portable power systems. We will show how the water balance operating point depends on the cell operating parameters and show the sensitivity to off-design conditions.

Water Balance in PEM and Direct Methanol Fuel Cells

2004 ◽  
Vol 2 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Michael G. Izenson ◽  
Roger W. Hill
Keyword(s):  
Fuel Cells ◽  
Water Balance ◽  
Power Systems ◽  
Direct Methanol Fuel Cells ◽  
Polymer Electrolyte Membrane ◽  
Pem Fuel Cells ◽  
Electrolyte Membrane ◽  
Direct Methanol ◽  
Specific Calculations ◽  
Methanol Fuel Cells

Water management is a critical design issue for polymer electrolyte membrane (PEM) fuel cells, because the PEM must be maintained at the proper water content to remain ionically conducting without flooding the electrodes. Furthermore, portable PEM power systems should operate at water balance to minimize weight. This paper presents the basic design relationships that govern water balance in a PEM fuel cell. Specific calculations are presented based on data from hydrogen/air and direct methanol fuel cells currently under development for portable power systems. We will show how the water balance operating point depends on the cell operating parameters and show the sensitivity to off-design conditions.

Fuel Cell Applications of Single Wall Carbon Nanotubes

2003 ◽  
Author(s):  
R. P. Raffaelle ◽  
B. Landi ◽  
T. Gennett ◽  
R. S. Morris ◽  
B. Dixon ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Direct Methanol Fuel Cells ◽  
Active Material ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Aspect Ratios

Novel carbon materials with nanometer dimensions are of potentially significant importance for a number of advanced technological applications. Currently, considerable interest exists in the possible applications of single wall carbon nanotubes (SWNTs) to proton exchange membrane (PEM) fuel cells. Proposed uses include as anode materials in both hydrogen and direct methanol fuel cells, solid polymer electrolyte additives, active cathode materials and bipolar plate interconnects. One of the desirable attributes afforded by the use of SWNTs in fuel cell applications stems from a combination of their extremely high electrical conductivity and large aspect ratios which results in a low weight percent for the electrical percolation threshold. This conductivity combined with the outstanding catalytic surface area offered by these nanostructured materials makes them a potentially outstanding active material for PEM electrodes. In addition, the high thermal conductivity, enhanced mechanical properties and corrosion resistance of polymer-SWNT composites may play a large role in developing new fuel cell designs such as thin-film microelectronic fuel cells. We will review the current applications involving SWNTs in PEM fuel cells and report on the recent work in the Nanopower Research Lab at RIT and it partners on utilizing high purity SWNT’s in microelectronic fuel cells.

Water and Thermal Balance in PEM Fuel Cells

2003 ◽  
Author(s):  
Michael G. Izenson ◽  
Roger W. Hill
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Balance ◽  
Electrochemical Performance ◽  
Thermal Management ◽  
Direct Methanol Fuel Cells ◽  
Pem Fuel Cell ◽  
Thermal Balance ◽  
Operating Conditions ◽  
Portable Power

The high energy density available from polymer electrolyte membrane (PEM) fuel cell systems makes them attractive sources of portable power. A key consideration for minimum weight portable power systems is that they must operate simultaneously at water balance (no external water supply) and thermal balance (controlled temperature). Water and thermal management are intimately linked since evaporation is a potent source of cooling. The cell’s electrochemical performance and the ambient environment determine the rates of water production and transport as well as heat generation and removal. This paper presents the basic design relationships that govern water and thermal balance in PEM fuel cell stacks and systems. Hydrogen/air and direct methanol fuel cells are both addressed and compared. Operating conditions for simultaneous water and thermal balance can be specified based on the cell’s electrochemical performance and the operating environment. These conditions can be used to specify the overall size and complexity of the cooling equipment needed in terms of the “UA” product of the heat exchangers. The water balance properties can have strong effects on the size of the thermal management equipment required.

Water and Thermal Balance in PEM and Direct Methanol Fuel Cells

2004 ◽  
Vol 1 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Michael G. Izenson ◽  
Roger W. Hill
Keyword(s):  
Fuel Cells ◽  
Water Balance ◽  
Power Systems ◽  
Thermal Management ◽  
Direct Methanol Fuel Cells ◽  
Polymer Electrolyte Membrane ◽  
Thermal Balance ◽  
Operating Conditions ◽  
Direct Methanol ◽  
Methanol Fuel Cells

A key consideration for portable power systems is that they must operate simultaneously at water balance (no external water supply) and thermal balance (controlled temperature). Water and thermal management are intimately linked since evaporation is a potent source of cooling. This paper presents the basic design relationships that govern water and thermal balance in polymer electrolyte membrane (PEM) fuel cell stacks and systems. Hydrogen/air and direct methanol fuel cells are both addressed and compared. Operating conditions for simultaneous water and thermal balance can be specified based on the cell’s electrochemical performance and the operating environment. These conditions can be used to specify the overall size and complexity of the cooling equipment. The water balance properties can have strong effects on the size of the thermal management equipment required.

scholarly journals Fuel Cell Power Systems for Maritime Applications: Progress and Perspectives

2021 ◽  
Vol 13 (3) ◽  
pp. 1213
Author(s):  
Hui Xing ◽  
Charles Stuart ◽  
Stephen Spence ◽  
Hua Chen
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Systems ◽  
Maritime Transportation ◽  
Pollutant Emissions ◽  
Maritime Industry ◽  
Molten Carbonate ◽  
Power Capacity ◽  
Processing Technologies ◽  
Power Sources

Fuel cells as clean power sources are very attractive for the maritime sector, which is committed to sustainability and reducing greenhouse gas and atmospheric pollutant emissions from ships. This paper presents a technological review on fuel cell power systems for maritime applications from the past two decades. The available fuels including hydrogen, ammonia, renewable methane and methanol for fuel cells under the context of sustainable maritime transportation and their pre-processing technologies are analyzed. Proton exchange membrane, molten carbonate and solid oxide fuel cells are found to be the most promising options for maritime applications, once energy efficiency, power capacity and sensitivity to fuel impurities are considered. The types, layouts and characteristics of fuel cell modules are summarized based on the existing applications in particular industrial or residential sectors. The various research and demonstration projects of fuel cell power systems in the maritime industry are reviewed and the challenges with regard to power capacity, safety, reliability, durability, operability and costs are analyzed. Currently, power capacity, costs and lifetime of the fuel cell stack are the primary barriers. Coupling with batteries, modularization, mass production and optimized operating and control strategies are all important pathways to improve the performance of fuel cell power systems.

SWNT Enhanced PEM Fuel Cells

2004 ◽  
Author(s):  
H. J. Ruf ◽  
B. J. Landi ◽  
R. P. Raffaelle
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Direct Methanol Fuel Cells ◽  
Weight Percent ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Cell Performance ◽  
Solid Polymer ◽  
Single Wall Carbon Nanotubes ◽  
Fuel Cell Performance

Considerable interest exists in the application of single wall carbon nanotubes (SWNTs) to proton exchange membrane fuel cells (PEMFCs). Proposed applications include use as anode materials in both hydrogen and direct methanol fuel cells, solid polymer electrolyte additives, active cathode materials, and bipolar plate interconnects. SWNTs have extremely high electrical conductivity and catalytic surface areas which make them potentially outstanding active materials for PEMFC electrodes. Additionally the enhanced mechanical properties may play a roll in developing new fuel cell designs such as thin-film microelectronic fuel cells. In a previous study SWNTs were combined with commercially obtained E-TEK Vulcan XC-72 and Nafion® to produce composite cathode membranes. The addition of nanotubes resulted in enhanced fuel cell performance over an equivalent weight percent doping of E-TEK alone. This increased performance was achieved with a 50% reduction in the quantity of platinum present in the cathode. In the present study we investigate fuel cell performance when both the anode and cathode membranes contain graphite, platinum and SWNTs. The SWNTs were characterized by use of thermogravimetric analysis, Raman and UV/VIS/NIR spectroscopes as well as high resolution field emission scanning electron microscopy. Fuel cell performance was determined by comparison of the IV characteristics.

Review on challenges of direct liquid fuel cells for portable application

2015 ◽  
Vol 12 (6) ◽  
pp. 591-606 ◽  
Author(s):  
Venkateswarlu Velisala ◽  
G. Naga Srinivasulu ◽  
B. Srinivasa Reddy ◽  
K. Venkata Koteswara Rao
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Density ◽  
Liquid Fuel ◽  
Electronic Devices ◽  
High Energy ◽  
Pem Fuel Cells ◽  
Green Energy ◽  
High Energy Density ◽  
Power Sources

Fuel cells technologies are the most promising green energy technologies for diverse applications. One of the fastest growing areas is the portable electronic applications where the power range is the order of 1–100 W. For most of the portable electronic devices, rechargeable battery is the major energy source. Due to limitations like limited capacity, requirement of external power for recharge have led many researchers to look for alternative power sources to power portable electronic devices. The high energy density of fuel cells makes them very attractive alternative to batteries for portable power applications. There are a variety of fuel cell technologies being considered to replace batteries in portable electronic equipment. Direct Liquid Fuel Cells (DLFCs) have attracted much attention due to their potential applications as a power source for portable electronic devices. The advantages of DLFCs over hydrogen fed PEM fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. Unlike batteries, fuel cells need not be recharged, merely refueled. This paper provides an overview on challenges of DLFCs (Direct Liquid Fuel Cells), like fuel crossover, cost, durability, water management, weight and size along with approaches being investigated to solve these challenges. Portable Fuel Cell Commercialization Targets for future and producers of portable fuel cells across the globe are also discussed in this paper.

scholarly journals Self-assembled network polymer electrolyte membranes for application in fuel cells at 250℃

2021 ◽  
Author(s):  
Seungju Lee ◽  
YoungSuk Jo ◽  
Son-Jong Hwang ◽  
Yongha Park ◽  
Yeong Cheon Kim ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Systems ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Membrane ◽  
High Energy ◽  
Pem Fuel Cells ◽  
Energy Storage And Conversion ◽  
Electrolyte Membrane ◽  
Self Assembled

Abstract Modern H2-based energy storage and conversion devices require a polymer electrolyte membrane (PEM) fuel cell–based integrated power system with synergistic heat integration. The key issue in integrated power systems is developing a PEM that can operate at 200–300 °C. However, currently used phosphoric-acid-based high-temperature PEM fuel cells limited stability at higher operating temperatures. Herein, we introduce a cerium hydrogen phosphate (CeHP) PEM that conducts protons above 200 °C through a self-assembled network (SAN). The SAN-CeHP-PBI reached maximum power densities of 2.4 W cm-2 and operate stably for over 7000 minute without any voltage decay at 250 ℃ under H2/O2 and anhydrous conditions. The developed fuel cell can be combined with an external hydrogen generator that uses a liquid hydrogen carrier such as N-ethylcarbazole and methanol as fuel, thus achieving a high energy efficiency. The thermal stability and fuel flexibility of these SAN-CeHP-PBI demonstrate potential for commercial applications.

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.

Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

2016 ◽  
Vol 30 (16) ◽  
pp. 1650155 ◽  
Author(s):  
Ebrahim Afshari ◽  
Masoud Ziaei-Rad ◽  
Nabi Jahantigh
Keyword(s):  
Heat Flux ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Pressure Drop ◽  
Flow Field ◽  
Pem Fuel Cells ◽  
Coolant Flow ◽  
Temperature Uniformity ◽  
Variable Heat ◽  
Variable Heat Flux

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.

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