Modelling the Inhomogeneous Stress Distribution in PEM Gas Diffusion Layers taking into Account Fiber Substrate and Microporous Layer

Proton exchange membrane fuel cells and electrolyzers rely on carbon fiber gas diffusion layers for effective reactant transport, water management, and mechanical support. The mechanical integrity behavior of the carbon fiber substrate and the microporous layer is critical during assembly due to compression-induced stresses. In this brief, a coupled mechanical model is used that captures the inhomogeneous stress and displacement distributions in the fiber/microporous layer composite structure under compression. The fiber substrate is modeled using 1D beam theory, while the MPL is represented through a 3D finite element method. An artificial composite structure is generated based on microstructural parameters. The model captures localized deformation and stress concentration phenomena consistent with experimental observations. Results reveal that the inhomogeneities in mechanical stiffness due to fiber clustering and MPL intrusion into fiber pores, can play a significant role in the overall cell mechanics. This work advances the understanding of GDL mechanical behavior and offers insights into improving fuel cell performance and longevity through more robust component design.