A Two Phase Model of a Phosphoric Acid Doped PEM Fuel Cell

2006 ◽  
Author(s):  
Denver F. Cheddie ◽  
Norman D. H. Munroe
Keyword(s):  
Fuel Cell ◽  
Phosphoric Acid ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Intermediate Temperature ◽  
Phase Model ◽  
Normal Operation ◽  
Two Phase

A two-phase model of an intermediate temperature (120–200 °C) proton exchange membrane (PEM) fuel cell is presented. This model accounts for two phase effects due to gas solubility in the phosphoric acid/PBI electrolyte, and considers aqueous phase electrochemical reactions. It accounts for all polarization and transport phenomena, and shows a good fit with experimental data in the temperature range (150–190 °C). This paper investigates catalyst utilization in intermediate temperature PEM fuel cells with phosphoric acid doped membranes. Simulations show that, under normal operation, 1–2% of the catalyst is utilized at both electrodes. Strategies are suggested to help reduce the cost of producing power from such systems.

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.

Nonlinear Analysis of Two-Phase Instabilities in PEMFC Parallel-Channel Cathodes

2010 ◽  
Author(s):  
Nicholas Siefert ◽  
Chi-Hsin Ho ◽  
Shawn Litster
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Liquid Water ◽  
Proton Exchange Membrane ◽  
Critical Issue ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Stoichiometric Ratio ◽  
Two Phase ◽  
Voltage Loss

Liquid water management is a critical issue in the development of proton exchange membrane (PEM) fuel cells. Liquid water produced electrochemically can accumulate and flood the microchannels in the cathodes of PEM fuel cells. Since the liquid coverage of the cathode can fluctuate in time for two-phase flow, the rate of oxygen transport to the cathode catalyst layer can also fluctuate in time, and this can cause the fuel cell power output to fluctuate. This paper will report experimental data on the voltage loss and the voltage fluctuations of a PEM fuel cell due to flooding as a function of the number of parallel microchannels and the air flow rate stoichiometric ratio. The data was analyzed to identify general scaling relationships between voltage loss and fluctuations and the number of channels in parallel and the air stoichiometric ratio. The voltage loss was found to scale proportionally to the square root of the number of channels divided by the air stoichiometric ratio. The amplitude of the fluctuations was found to be linearly proportional to the number of microchannels and inversely proportional to the air stoichiometric ratio squared. The data was further analyzed by plotting power spectrums and by evaluating the non-linear statistics of the voltage time-series.

Progress on Reflective Terahertz Imaging for Identification of Water in Flow Channels of PEM Fuel Cells

2011 ◽  
Vol 110-116 ◽  
pp. 2301-2307
Author(s):  
P. Buaphad ◽  
P. Thamboon ◽  
C. Tengsirivattana ◽  
J. Saisut ◽  
K. Kusoljariyakul ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Water Distribution ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Thz Radiation ◽  
Promising Tool ◽  
Flow Channels ◽  
Exchange Membrane

This work reports an application of reflective terahertz (THz) imaging for identification of water distribution in the proton exchange membrane (PEM) fuel cell. The THz radiation generated from relativistic femtosecond electron bunches is employed as a high intensity source. The PEM fuel cell is designed specifically for the measurement allowing THz radiation to access the flow field region. The THz image is constructed from reflected radiation revealing absorptive area of water presence. The technique is proved to be a promising tool for studying water management in the PEM fuel cell. Detailed experimental setup and results will be described.

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.

In-Situ Measurements of Water Transfer Due to Different Mechanisms in a PEM Fuel Cell

2007 ◽  
Author(s):  
Attila Husar ◽  
Andrew Higier ◽  
Hongtan Liu
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Membrane Electrode Assembly ◽  
Pem Fuel Cells ◽  
Water Transfer ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Order Of Magnitude

Water management is of critical importance in a proton exchange membrane (PEM) fuel cell. Yet there are very limited studies of water transfer through the membrane and no data are available for water transfer due to individual mechanisms through the membrane electrode assembly (MEA) in an operational fuel cell. Thus it is the objective of this study to measure water transfer through the MEA due to different mechanisms through the membrane electrode assembly (MEA) of an operational PEM fuel cell. The three different mechanisms of water transfer, i.e., electro-osmotic drag, diffusion and hydraulic permeation were isolated by specially imposed boundary conditions. Therefore water transfer through the MEA due to each mechanism could be measured separately. In this study, all the data were collected in an actual assembled operational fuel cell, and some of the data were collected while the fuel cell was generating power. The measured results showed that water transfer due to hydraulic permeation, i.e. the pressure difference between the anode and cathode is at least an order of magnitude lower than those due to other two mechanisms. The data for water transfers due to electro-osmosis and diffusion through the MEA are in good agreement with some of the data and model predications in the literature for the membrane. The methodology used in this study is simple and can be easily adopted for in-situ water transfer measurement due to different mechanisms in actual PEM fuel cells without any cell modifications.

Corrosion-Resistant Tantalum Coatings for PEM Fuel Cell Bipolar Plates

2002 ◽  
Vol 756 ◽  
Author(s):  
Leszek Gladczuk ◽  
Chirag Joshi ◽  
Anamika Patel ◽  
Jim Guiheen ◽  
Zafar Iqbal ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Substrate Surface ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Body Centered Cubic ◽  
Bipolar Plates ◽  
Corrosion Resistant ◽  
Tantalum Coatings

ABSTRACTTantalum is a tough, corrosion resistant metal, which would be suitable for use as bipolar plates for proton exchange membrane (PEM) fuel cells, if it was not for its high weight and price. Relatively thin tantalum coatings, however, can be deposited on other inexpensive and lighter weight metals, such as aluminum and steel, providing a passive protection layer on these easily formed substrates. We have successfully deposited, high quality α (body-centered-cubic, bcc) and β (tetragonal) phase tantalum coatings that were a few micrometers thick by dc magnetron sputtering on steel and aluminum. The growth of the thermodynamically preferred body-centered-cubic (bcc) tantalum phase was induced by a choice of deposition conditions and substrate surface treatment. The microstructure and corrosion resistance of the α-phase in an environment approximately simulating the electrochemical conditions used in a PEM fuel cell were investigated under potentiodynamic conditions. Preliminary potentiostatic measurements of a β-phase sample are also presented.

Development of an Optical Sensor for Temperature Measurement and Water Droplet Detection in PEMFC Gas Channels

2011 ◽  
Author(s):  
Kristopher Inman ◽  
Xia Wang ◽  
Brian Sangerozan
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Temperature Measurement ◽  
Water Droplet ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Droplet Movement ◽  
Temperature Measurement System

Thermal and water management in Proton Exchange Membrane (PEM) fuel cells provide a significant challenge for engineers and fuel cell designers as both have a direct effect on performance and durability. Internal temperature is very difficult to measure due to component geometry and the internal environment possessed by PEM fuel cells along with a lack of sufficient temperature measurement methods which are often highly invasive. This research presents initial developments for creating a non-intrusive temperature measurement system, based on the principles of phosphor thermometry, which also has the ability to optically detect liquid water formation and movement in PEMFC gas channels. The sensor was designed, calibrated and then installed in a 25 cm2 PEM fuel cell for in-situ testing. The experimental data show that a relationship exists between temperature variation and water droplet movement in gas channels of a PEM fuel cell.

Transparent PEM Fuel Cells for Direct Visualization Experiments

2010 ◽  
Vol 7 (6) ◽  
Author(s):  
M. I. Rosli ◽  
D. J. Borman ◽  
D. B. Ingham ◽  
M. S. Ismail ◽  
L. Ma ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Field Pattern ◽  
Direct Visualization ◽  
Serpentine Flow Field ◽  
Water Behavior

This paper reviews some of the previous research works on direct visualization of water behavior inside proton exchange membrane (PEM) fuel cells using a transparent single cell. Several papers which have employed the method have been selected and summarized, and a comparison between the design of the cell, materials, methods, and visual results are presented. The important aspects, advantages of the method, and a summary on the previous investigations are discussed. Some initial works on transparent PEM fuel cell design using a single serpentine flow-field pattern are described. The results show that the direct visualization via transparent PEM fuel cells could be one potential technique for investigating the water behavior inside the channels and a very promising way forward to provide useful data for validation in PEM fuel cell modeling and simulation.

scholarly journals High temperature PEM fuel cell steady-state transport modeling

2013 ◽  
Vol 24 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Viorel Ionescu
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Waste Heat ◽  
Water Concentration ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Electrochemical Kinetics

AbstractA fuel cell is a device that can directly transfer chemical energy to electric and thermal energy. Proton exchange membrane fuel cells (PEMFC) are highly efficient power generators, achieving up to 50-60% conversion efficiency, even at sizes of a few kilowatts. There are several compelling technological and commercial reasons for operating H2/air PEM fuel cells at temperatures above 100 °C; rates of electrochemical kinetics are enhanced, water management and cooling is simplified, useful waste heat can be recovered, and lower quality reformed hydrogen may be used as the fuel. All of the High Temperature PEMFC model equations are solved with finite element method using commercial software package COMSOL Multiphysics. The results from PEM fuel cell modeling were presented in terms of reactant (oxygen and hydrogen) concentrations and water concentration in the anode and cathode gases; the polarization curve of the cell was also displayed.

Effects of CO on Performance of HT-PEM Fuel Cells

2013 ◽  
Vol 724-725 ◽  
pp. 723-728
Author(s):  
Xue Nan Zhao ◽  
Hong Sun ◽  
Zhi Jie Li
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Large Scale ◽  
Proton Exchange Membrane ◽  
High Efficiency ◽  
Electrochemical Reaction ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Fuel Cell Performance

High temperature proton exchange membrane (HT-PEM) fuel cell is considered as one of the most probable fuel cells to be large-scale applied due to characteristics of high efficiency, friendly to environment, low fuel requirement, ease water and heat management, and so on. However, carbon monoxide (CO) content in fuel plays an important role in the performance of HT-PEM fuel cells. Volt-ampere characteristics and AC impedance of HT-PEM fuel cell are tested experimentally in this paper, and effects of CO in fuel on its performance are analyzed. The experimental results show that CO in fuel increases remarkably the Faraday resistance of HT-PEM fuel cell and decreases the electrochemical reaction at anode; the more CO content in fuel is, the less HT-PEM fuel cell performance is; with the increasing cell temperature, the electrochemical reaction on the surface of catalyst at anode is improved and the poisonous effects on the HT-PEM fuel cell are alleviated.

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