Enhancement of Oxygen Diffusion in a Gas Diffusion Layer of a Fuel Cell Electrode by Magnetizing Force

2010 ◽  
Author(s):  
Eiji Tasaka ◽  
Yutaka Asako
Keyword(s):  
Diffusion Layer ◽  
Oxygen Transfer ◽  
Oxygen Diffusion ◽  
Air Flow ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Magnetic Flux Density ◽  
Fuel Cell Electrode ◽  
Magnetizing Force ◽  
Cell Electrode

Possibility of enhancement of oxygen diffusion in a gas diffusion layer of a fuel cell electrode is numerically investigated. Since oxygen is paramagnetic gas, it is attracted to a field of high magnetic flux density by the magnetizing force. If there exists gradient of the oxygen concentration and the gradient of magnetic flux density in the gas diffusion layer, air flow occurs in the layer. Numerical computations were conducted for air flow in the gas diffusion layer of the electrode under the magnetic field which is generated by parallel electric currents. Darcy model is used to represent the air flow in the layer and the oxygen concentration was solved. The effects of the permiability of the electrode, intensity of the electric current, the location of the electric wire and the thickness of the electrode on the enhancement of oxygen transfer were investigated. As a result, 5 to 20% of enhancement of oxygen transfer by using magnetizing force was observed.

Effect of Carbon Fiber Felt Pretreatment on Properties of Carbon Fiber Paper

2011 ◽  
Vol 194-196 ◽  
pp. 1620-1623 ◽  
Author(s):  
Xue Jun Zhang ◽  
Hao Pei ◽  
Zeng Min Shen
Keyword(s):  
Fuel Cell ◽  
Carbon Fiber ◽  
Diffusion Layer ◽  
Gas Permeability ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Carbon Fiber Felt ◽  
Fuel Cell Electrode ◽  
Carbon Fiber Paper ◽  
Cell Electrode

Gas diffusion layer is a very important component in fuel cell, and carbon fiber paper is widely used as substrate of gas diffusion layer. This paper has developed one way to produce carbon fiber paper from carbon fiber felt with or without pretreatment. The properties and microstructure of carbon fiber paper were also stdied. The results show that the pretreatment of carbon fiber felt is helpful to prepare carbon fiber paper with good properties. The content of carbon derived from resin during pretreatment has effects on density, thickness, porosity, gas permeability, porosity and tensile streagth of carbon fiber paper. Carbon fiber paper made from carbon fiber felt with pretreatment has better interface adhension than that of carbon fiber paper made from carbon fiber felt without pretreatment. Carbon fiber paper was produced with thickness of 0.28mm, density of 0.43g/cm3, porosity of 77%, gas permeability of 2500 mL•mm/(cm2•hr•mmAq), specific resistance of 0.017Ω•cm and tensile strength of 18MPa, which is a promising materials for fuel cell electrode.

Modeling of Flooding Phenomena in Hydrophobic Gas Diffusion Layer of PEFC

2007 ◽  
Author(s):  
Kazuhiko Kudo ◽  
Akiyoshi Kuroda ◽  
Shougo Takeoka ◽  
Yosuke Shimazu
Keyword(s):  
Diffusion Layer ◽  
Liquid Water ◽  
Air Flow ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Flow Channel ◽  
Cathode Side ◽  
Model Following ◽  
Condensed Water ◽  
Different Diameters

The mechanism of liquid water removal, water vapor diffusion and oxygen diffusion in cathode side gas diffusion layer (GDL) of PEFC is studied by modeling the GDL as a hydrophobic flat plate with many straight holes with different diameters. As the results of the consideration using the model, following results are obtained. The spots where liquid water condensation is taken place between GDL-MEA gap are limited to the inlets of holes with larger diameters, and the condensed water is drained to air flow channel only through the larger holes. Other holes with smaller diameters are free of liquid water, and oxygen diffuses from the air flow channel to the catalyst surface through such holes. The reduction of output voltage of fuel cell due to the increase in the current density may be caused by the reduction of the oxygen concentration in GDL-MEA gap. The condensate tends to penetrate into larger holes instead of filling the gap of GDL and MEA.

G133 Oxygen Diffusion Characteristics of Gas Diffusion Layer with Moisture

2007 ◽  
Vol 2007 (0) ◽  
pp. 239-240 ◽  
Author(s):  
Yutaka TASAKI ◽  
Shixue WANG ◽  
Yasushi ICHIKAWA ◽  
Denis. Kramer ◽  
Pierre. Boillat ◽  
...  
Keyword(s):  
Diffusion Layer ◽  
Oxygen Diffusion ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Diffusion Characteristics

E144 Oxygen Diffusion Characteristics for Wet Gas Diffusion Layer

2006 ◽  
Vol 2006 (0) ◽  
pp. 177-178
Author(s):  
Shixue WANG ◽  
Yoshio UTAKA ◽  
Yutaka TASAKI ◽  
Masanori MOCHIMARU
Keyword(s):  
Diffusion Layer ◽  
Oxygen Diffusion ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Wet Gas ◽  
Diffusion Characteristics

Measurement of Oxygen Diffusion Characteristics of Porous Media Used for the Gas Diffusion Layer of Proton-Exchange Membrane Fuel Cells

2007 ◽  
Author(s):  
Shixue Wang ◽  
Yoshio Utaka ◽  
Yutaka Tasaki
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Experimental Method ◽  
Diffusion Layer ◽  
Oxygen Diffusion ◽  
Proton Exchange Membrane ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Exchange Membrane

It is known that the mass transfer characteristics of the gas diffusion layer (GDL) are closely related to the performance of a proton-exchange membrane fuel cell. In this study, an experimental method was established for measuring the gas diffusion coefficient in porous media by using an oxygen concentration sensor based on a galvanic battery operating at normal temperature. The oxygen diffusion coefficient in air measured by this method corresponded with data in the literature within ±6% deviation. The oxygen diffusion coefficients of two kinds of porous media generally used for the GDL were measured by the experimental method for dry and wet samples. The results indicate that the gas diffusion coefficient in porous media not only depends on porosity but is also affected by other factors, for example, tortuosity. It was also found that the diffusion coefficient in different directions, for example, through-plane and in-plane, in porous media can be very different. The oxygen diffusion coefficient in the porous media containing liquid water varied nonlinearly with the saturation level and was strongly affected by other factors as well.

scholarly journals Interaction of Vibration and Air Flow-Accelerating Droplet Emission from the Gas Diffusion Layer of Proton Exchange Membrane Fuel Cell

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Sitong Chen ◽  
Xueke Wang ◽  
Tong Zhu ◽  
Xiaofeng Xie
Keyword(s):  
Diffusion Layer ◽  
High Speed ◽  
Proton Exchange Membrane ◽  
Air Flow ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Vertical Vibration ◽  
Proton Exchange ◽  
Elevated Frequency ◽  
Exchange Membrane

In order to explore the influence of vibration that the vehicles are often subjected on water management of PEMFC, the dynamic characteristics of vibrating droplet on gas diffusion layer (GDL) surface were investigated through a high-speed image technology. The operating condition of vertical and horizontal excitations separately or coupled with air flow under different frequencies and amplitudes are applied on the substrate, so that the laws for the transition from Wenzel-Cassie regime to Cassie regime and the contact angle, the deformation rate for the width and height are obtained. It is observed that the wetting diameter of the droplet is smaller than the initial value under vertical vibration, making it easier for the gas to discharge the water droplets from the PEMFC. For the horizontal excitation, the droplet is pulled apart when the applied energy exceeded the cohesive energy at elevated frequency and amplitude. Moreover, as to the interaction of vibration and air flow, the droplet was more likely to move forward under the gas-driven force.

Measurement Technique of Oxygen Diffusion Resistance through Gas Diffusion Layer

2013 ◽  
Vol 58 (1) ◽  
pp. 889-895
Author(s):  
H. Ohira ◽  
K. Kikuchi ◽  
A. Ida ◽  
J. Tomiyasu ◽  
A. Yamamoto
Keyword(s):  
Diffusion Layer ◽  
Measurement Technique ◽  
Oxygen Diffusion ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Diffusion Resistance
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