scholarly journals In-Plane Thermal Conductivity of PEM Fuel Cell Gas Diffusion Layers

2011 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Ned Djilali ◽  
Majid Bahrami
Keyword(s):  
Thermal Conductivity ◽  
Fuel Cell ◽  
Effective Thermal Conductivity ◽  
Thermal Contact ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Carbon Paper ◽  
Test Bed ◽  
Diffusion Layers ◽  
Wide Range

Heat transfer through the gas diffusion layer (GDL) is a key process in the design and operation of a PEM fuel cell. The analysis of this process requires determination of the effective thermal conductivity. This transport property differs significantly in the through-plane and in-plane directions due to the anisotropic micro-structure of the GDL. In the present study, a novel test bed that allows the separation of in-plane effective thermal conductivity and thermal contact resistance in GDLs is described. Measurements are performed using Toray carbon paper TGP-H-120 samples for a range of PTFE content at a mean temperature of 65–70°C. The measurements are complemented by a compact analytical model that achieves good agreement with the experimental data. The in-plane effective thermal conductivity is found to be about 12 times higher than the through-plane conductivity and remains approximately constant, k ≈ 17.5 W/mK, over a wide range of PTFE content.

scholarly journals Effect of Compression on the Effective Thermal Conductivity and Thermal Contact Resistance in PEM Fuel Cell Gas Diffusion Layers

2010 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Ned Djilali ◽  
Majid Bahrami
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Fuel Cell ◽  
Contact Resistance ◽  
Effective Thermal Conductivity ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Analytical Models

Heat transfer through the gas diffusion layer (GDL) of a PEM fuel cell is a key process in the design and operation a PEM fuel cell. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance between the GDL and adjacent surfaces/layers. In the present study, a guarded-hot-plate apparatus has been designed and built to measure the effective thermal conductivity and thermal contact resistance in GDLs under vacuum and atmospheric pressure. Toray carbon papers with the porosity of 78% and different thicknesses are used in the experiments under a wide range of compressive loads. Moreover, novel analytical models are developed for the effective thermal conductivity and thermal contact resistance and compared against the present experimental data. Results show good agreements between the experimental data and the analytical models. It is observed that the thermal contact resistance is the dominant component of the total thermal resistance and neglecting this phenomenon may result in enormous errors.

A 5-cm2 PEM Fuel Cell Gas Diffusion Layer Experimental Study and Scanning Electron Microscopy Visualization

2019 ◽  
Author(s):  
Jose Montoya Segnini ◽  
Gerardo Carbajal
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fuel Cell ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Carbon Paper ◽  
Carbon Cloth ◽  
Gas Diffusion Layers ◽  
Diffusion Layers ◽  
Scanning Electron

Abstract The present experimental study aims to determine the effect of two different gas diffusion layers in the performance of a 5-cm2 proton exchange membrane (PEM) fuel cell. The gas diffusion layers consisted of a carbon cloth gas diffusion (GDL-CT) and a non-woven carbon paper (Sigracet 25 BC, Sigracet 29, and BC Sigracet 35 BC). The effect of the GDL parameters on the fuel cell performance was evaluated by the polarization curve. Based on the polarization curve results, it was confirmed that the carbon cloth gas diffusion layer had a better performance than the non-woven carbon. Different temperatures, hydrogen flow rates and inlet pressures were tested. Images from the scanning electron microscopy were obtained to visualize the internal structure of a carbon paper GDL and a carbon cloth GDL; it was observed different surface structures between them.

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