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.

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.

scholarly journals A Study on the Evaluation of Effective Properties of Randomly Distributed Gas Diffusion Layer (GDL) Tissues with Different Compression Ratios

2020 ◽  
Vol 10 (21) ◽  
pp. 7407
Author(s):  
Haksung Lee ◽  
Chan-Woong Choi ◽  
Ki-Weon Kang ◽  
Ji-Won Jin
Keyword(s):  
Fuel Cell ◽  
Carbon Fiber ◽  
Diffusion Layer ◽  
Effective Properties ◽  
Compressive Load ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Fiber Content ◽  
Equivalent Material ◽  
Carbon Cloth

The gas diffusion layer (GDL) typically consists of a thin layer of carbon fiber paper, carbon cloth or nonwoven and has numerous pores. The GDL plays an important role that determines the performance of the fuel cell. It is a medium through which hydrogen and oxygen are transferred and serves as a passage through which water, generated by the electrochemical reaction, is discharged. The GDL tissue undergoes a compressive loading during the stacking process. This leads to changes in fiber content, porosity and resin content due to compressive load, which affects the mechanical, chemical and electrical properties of the GDL and ultimately determines fuel cell performance. In this study, the geometry of a GDL was modeled according to the compression ratios (10%, 20%, 30%, 40% and 50%), which simulated the compression during the stacking process and predicted the equivalent properties according to the change of GDL carbon fiber content, matrix content and pore porosity, etc. The proposed method to predict the equivalent material properties can not only consider the stacking direction of the material during stack assembling process, but can also provide a manufacturing standard for fastening compressive load for GDL.

Carbon fiber paper for fuel cell electrode☆

Fuel ◽  
2002 ◽  
Vol 81 (17) ◽  
pp. 2199-2201 ◽  
Author(s):  
Xuejun Zhang ◽  
Zengmin Shen
Keyword(s):  
Fuel Cell ◽  
Carbon Fiber ◽  
Fuel Cell Electrode ◽  
Carbon Fiber Paper ◽  
Cell Electrode

Effects of Assembly Pressure on the Gas Diffusion Layer and Performance of a PEM Fuel Cell

2011 ◽  
Vol 110-116 ◽  
pp. 48-52 ◽  
Author(s):  
Hao Ming Chang ◽  
Min Hsing Chang
Keyword(s):  
Fuel Cell ◽  
Diffusion Layer ◽  
Gas Permeability ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Carbon Paper ◽  
Membrane Electrode ◽  
Clamping Pressure

Assembly pressure plays an important role in the factors affecting the performance of a PEM fuel cell. An insufficient clamping pressure may cause large contact resistance and thus lower the cell performance. On the other hand, over-clamping may reduce the porosity and permeability of the gas diffusion layer (GDL) and also result in poor cell performance. Therefore, it is very important to determine the proper assembly pressure for obtaining optimal performance. In this study, we design a special test fixture to evaluate the effect of assembly pressure on the performance of a PEM fuel cell. Without disassembling the fuel cell, the clamping pressure can be adjusted in situ to measure the cell performance directly and precisely. The unique single cell design eliminates the influence of gasket around the membrane electrode assembly (MEA) and makes it possible to estimate the compression effect of GDL independently. Three different types of carbon paper are used in the experiments as the GDLs. The variations of water contact angle, gas permeability, and in-plane electrical resistivity with the assembly pressure are also measured to explore the effects of assembly pressure on these physical properties. The results show that an optimal assembly pressure is always observed in each case, indicating an adequate compression on GDL is quite necessary for fuel cells.

Sign in / Sign up

Export Citation Format

Share Document