Operating Polymer Electrolyte Membrane Research Articles

In Situ Investigation of Water Distribution in Polymer Electrolyte Fuel Cell Using Neutron Radiography

This paper investigates the water content within operating polymer electrolyte membrane (PEM) fuel cells using neutron radiography. We consider fuel cells with various PTFE loadings in their gas diffusion layers (GDL) and microporous layers (MPL), and examine the impacts of MPL/GDL properties on the liquid water behavior and fuel cell performance. Fuel cells are tested at both dry and fully hydrated conditions with different serpentine flow fields. Water contents in the projected areas of channel and land regions are probed. We find that the fuel cell may be subject to more flooding at low current-density operation. Both MPL and GDL wetting properties have substantial impacts on the water content. Cell performance also varies on different scenarios of the MPL/GDL wetting properties. The quad-channel flow field exhibits higher water content without remarkable change in performance at low current densities. Liquid water profile along the channel is presented and on-set clearly indicated.

Simultaneous In Situ Measurement of Temperature and Relative Humidity in a PEMFC Using Optical Fiber Sensors

The development, implementation, and demonstration of in-fiber Bragg grating (FBG) sensors for a simultaneous measurement of temperature and relative humidity (RH) in an operating polymer electrolyte membrane fuel cell (PEMFC) are presented. Etched fiber, polymer-coated FBG sensors with fast response and high sensitivity are installed in situ in a minimally invasive manner in the cathode unipolar plate of a single PEMFC with serpentine flow fields. The performance of the fuel cell under transient operating conditions is monitored. Step increases in current induce significantly larger increases in RH near the outlet than near the inlet of the cell, and associated transients within the fuel cell are found on a time scale approaching the sensor response time . The improved response of the technique, together with the significantly improved temperature and RH resolution, provides useful information on the dynamics of heat and water management. The technique is well suited for distributed measurements, and its relatively low cost and nonintrusive character make it a good candidate for practical multipoint monitoring of complete stacks.

Magnetic Resonance Imaging of Water in Operating Polymer Electrolyte Membrane Fuel Cells

Fuel CellsVolume 9, Issue 5 p. 760-760 ErratumFree Access Magnetic Resonance Imaging of Water in Operating Polymer Electrolyte Membrane Fuel Cells† This article corrects the following: Magnetic Resonance Imaging of Water in Operating Polymer Electrolyte Membrane Fuel Cells S. Tsushima, S. Hirai, Volume 9Issue 5Fuel Cells pages: 506-517 First Published online: July 28, 2009 S. Tsushima, S. Tsushima tsushima@mech.titech.ac.jp Research Center for Carbon Recycling and Energy, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552, JapanSearch for more papers by this authorS. Hirai, S. Hirai Research Center for Carbon Recycling and Energy, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552, JapanSearch for more papers by this author S. Tsushima, S. Tsushima tsushima@mech.titech.ac.jp Research Center for Carbon Recycling and Energy, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552, JapanSearch for more papers by this authorS. Hirai, S. Hirai Research Center for Carbon Recycling and Energy, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552, JapanSearch for more papers by this author First published: 29 September 2009 https://doi.org/10.1002/fuce.200990016 † Paper presented at the LANL-NEDO-AIST Workshop, October 26 – November 1, 2007, Tokyo, Japan. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume9, Issue5October, 2009Pages 760-760 RelatedInformation

Magnetic Resonance Imaging of Water in Operating Polymer Electrolyte Membrane Fuel Cells

AbstractWater management in polymer electrolyte membrane fuel cells (PEMFCs) is extremely important for the high performance and durable operation of fuel cells. Therefore, fundamental understanding of water transport involved in operating PEMFCs is necessary. This article presents a review of in situ magnetic resonance imaging (MRI) visualisation of water in operating PEMFCs, which is recognised as a powerful diagnostic tool for probing water behaviours, both in flow fields and in the membrane electrode assembly (MEA). The basic principles and hardware related to MRI visualisation are described with emphasis on the design, construction and material selection of a PEMFC for MRI experiments. The MRI results reported by several groups are outlined to illustrate the versatility and potential usefulness of in situ visualisation of water in operating PEMFCs using MRI.

Modeling and Experimental Analyses of a Two-Cell Polymer Electrolyte Membrane Fuel Cell Stack Emphasizing Individual Cell Characteristics

Performance of individual cells in an operating polymer electrolyte membrane (PEM) fuel cell stack is different from each other because of inherent manufacturing tolerances of the cell components and unequal operating conditions for the individual cells. In this paper, first, effects of different operating conditions on performance of the individual cells in a two-cell PEM fuel cell stack have been experimentally investigated. The results of the experiments showed the presence of a voltage difference between the two cells that cannot be manipulated by operating conditions. The temperature of the supplying air among others predominantly influences the individual cell voltages. In addition, those effects are explored by using a dynamic model of a stack that has been developed. The model uses electrochemical voltage equations, dynamic water balance in the membrane, energy balance, and diffusion in the gas diffusion layer, reflecting a two-phase phenomenon of water. Major design parameters and an operating condition by conveying simulations have been changed to analyze sensitivity of the parameters on the performance, which is then compared with experimental results. It turns out that proton conductivity of the membrane in cells among others is the most influential parameter on the performance, which is fairly in line with the reading from the experimental results.

Investigation of Current Density Effect on Water Vapor Concentration Profile along PEMFC Channels by TDLAS

In this article, we applied tunable diode laser absorption spectroscopy (TDLAS) technique to measure variation of water vapor concentration in gas flow channels in an operating polymer electrolyte membrane fuel cell (PEMFC). TDLAS measurement offered an optical remote sensing to detect slight change of water vapor concentration, showing that electrochemical reaction in an operating PEMFC is not uniformly observed. We performed TDLAS measurement in gas flow channels in the anode and the cathode with variation of cell current density. We observed increase of water vapor concentration due to electrochemical reaction along the cathode channel as well as along the anode channel from the inlet, suggesting that generated water was exhausted through the both channels. It was also shown that less electrochemical reaction was observed in the upstream of the channel presumably due to less hydration of the membrane because of dry gas supply.

In-situ Measurement of Water Vapor and Oxygen Concentration in a PEMFC Channel by Tunable Diode Laser Absorption Spectroscopy Techniques

n this study in-situ measurements of water vapor and oxygen concentration in gas flow channels in an operating polymer electrolyte membrane fuel cell (PEMFC) are obtained using Tunable Diode Laser Absorption Spectroscopy (TDLAS). Wavelengths of the diode laser are 1392nm for measurement of water vapor concentration and 760nm for measurement of oxygen concentration, respectively. It was successfully demonstrated that the optical remote sensing based on TDLAS techniques can detect local variations of oxygen and water vapor concentration in the channel of a PEMFCs under load.

Lanthanide–Platinum Intermetallic Compounds as Anode Electrocatalysts for Direct Ethanol PEM Fuel Cells: II. Performance of Nanopowders in an Operating PEM Fuel Cell

The electrochemical stability and electrocatalytic performance in ethanol oxidation of a new class of anode electrocatalysts is presented. Nanopowders of the Laves-phase intermetallic compounds were utilized to exploit the strong oxidizing power of tetravalent lanthanides in an anode electrocatalyst. These nanopowders are stable in the environment of the anode of a polymer electrolyte membrane (PEM) fuel cell. Steady-state polarization curves in an operating PEM fuel cell demonstrate that the new electrocatalysts are active toward the electro-oxidation of ethanol. The new electrocatalysts exhibited ca. more overpotential than PtRu at a given current density based on the total electrocatalyst surface area in the anode, but this may be due to issues with particle size and electrode structure. Analysis of the anode effluent with on-line gas chromatography showed that two-electron electro-oxidation to acetaldehyde was the main reaction pathway at potentials of interest and implied that ethanol adsorbs without C–C bond cleavage through the oxygen in the hydroxyl group.

In situ neutron imaging technique for evaluation of water management systems in operating PEM fuel cells

This paper explores the method of neutron imaging as an experimental tool to perform in situ non-destructive analysis on an operating polymer electrolyte membrane hydrogen fuel cell. Neutrons are ideal for the imaging of hydrogen fuel cells because of their sensitivity to hydrogen-containing compounds such as water. This research focused on using imaging techniques to develop methods for testing and evaluating the water management system of a fuel cell. A real-time radiography dataset consisting of 1000 images at 2-s intervals was used to create a movie which showed water production, transport, and removal throughout the cell. This dataset was also analyzed to quantify and calculate the amount of water present in the cell at any time and masking techniques were used to differentiate between water in the cell flow channels and in the gas diffusion layer. Additionally, a tomography dataset allowed for the creation of a digital 3-dimensional (3-D) reconstruction of the dry cell which can be analyzed for structural defects.

An In Situ Method for Determination of Current Distribution in PEM Fuel Cells Applied to a Direct Methanol Fuel Cell

This paper describes and demonstrates a new method for determination of current density distribution in an operating polymer electrolyte membrane (PEM) fuel cell. The technique is a modification of the current mapping technique that relies on an array of shunt resistors embedded within a current collecting plate. Standard, nonaltered membrane electrode assemblies are utilized with gas diffusion layers in direct contact with an electrically segmented current collector/flow field. Multiple current measurements are taken simultaneously, allowing transient distribution detection with a multichannel potentiostat. Both steady state and transient data are presented for an operating liquid fed direct methanol fuel cell. Cathode flooding is predicted, and shown to occur at relatively high cathode flow rates. This technique can contribute to knowledge and understanding of key phenomena including water management and species distribution in PEM fuel cells. © 2002 The Electrochemical Society. All rights reserved.