A Comprehensive Fractal Approach in Determination of the Effective Thermal Conductivity of Gas Diffusion Layers in Polymer Electrolyte Membrane Fuel Cells

Abstract

The challenges in the fuel cell industry is to produce the efficient thermal and water management for accurate determination the effectiveness thermal conductivity of gas diffusion layers (GDL) used in polymer electrolyte membrane fuel cells (PEMFC’s). This is one of the factors affecting the durability of a fuel cell and need to get a solution to minimize costs and optimize the use of electrodes and cells. The main objective of this research is focusing on the capability of the fractal approach for estimation effectiveness thermal conductivity of gas diffusion media. Moreover, on this research also to propose modified fractal equations in determination of the effective thermal conductivity of GDL in PEMFCs based on previous study. Other objectives in this study are demonstrated the thermal conductivity of GDL treated with PTFE contents by using through-plane thermal conductivity experiment method. The through plane method (experimental method) has been used in estimating thermal conductivity of the GDL. Thermal resistance for GDL also has been investigating under compression pressure 0.1 Mpa until 1.0 MPa. In fractal equation, the determination of tortuous and pore fractal dimension can be done by using Scanning Electron Microscopy (SEM) method. Determination of effectiveness thermal conductivity using of fractal equation with slightly modified. In findings, it was found that fractal equation have been modified measured on the GDL parameter characteristics shows the effectiveness thermal conductivity of GDL for Toray carbon paper 060 and 090 is 0.3218 W/mK and 0.3306 W/mK respectively, compared to through plane thermal conductivity experimental value which is 0.3378 W/mK and 0.3236 W/mK respectively. For Sigracet 35 AA and 35 BA by using fractal approach technique is 0.1619 W/mK and 0.1182 W/mK respectively, compared to through plane thermal conductivity experimental value which is 0.1594 W/mK and 0.2752 W/mK respectively.