Determination of the Orthotropic Mechanical Elastic Properties of Gas Diffusion Layers for PEMFCs

One of the most important components of proton exchange membrane fuel cell is the gas diffusion layer (GDL), due to its position between the catalyst layers, where the electrochemical reactions take place, and the bipolar plates supplying the reactant gases. The GDL must have an optimal mechanical stiffness to ensure the transport of the different gases and the water produced by the fuel cell operation. Measuring the mechanical properties of the different GDLs available in the market require the development of specific methodologies due to their orthotropic behavior. This article aims to assess and create a database for selecting GDLs for specific applications and assisting engineers in fuel cell modeling. This study focuses on developing robust characterization methods to assess the different properties of GDLs in different directions: within the plane, along both the machine and transverse directions, and perpendicular to the plane. These tests allow to determine parameters like in-plane tensile and shear moduli, out-of-plane compression and shear moduli, and in-plane Poisson's ratios. By examining a wide range of commercial specimens, including different types, area weights, hydrophobic treatments, manufacturing processes, and microporous layers, this study aims to provide a comprehensive analysis of the orthotropic mechanical properties of GDLs.