Modeling the original and cyclic compression behavior of non-woven gas diffusion layers for fuel cells

Abstract

It is established that the compression behavior of gas diffusion layers (GDL) is dependent on the level of the mechanical stress it experienced during its lifetime. As a matter of fact, every cycle of compression induces damages in the GDL, including fibers breakage and/or their spatial reorganization. As observed in the experimental work, the first cycle of compression of GDLs as received from the suppliers is already altered by a previous compression that is applied during the manufacturing process. This paper then presents a model able to predict the cyclic behavior of GDL, considering the existence of this compressive stress applied during the manufacturing process. The experimental mechanical properties of the three main types of non-woven GDL (rolls, sheets and felts) were first measured and then predicted using the proposed model, thereby allowing to separate the influences of the manufacturing process, the type of fibers, the presence of a micro-porous layer and a hydrophobic treatment on the GDL.