Modeling study on anisotropic heat conduction of PEMFC GDLs facilitated by Micro-CT

The gas diffusion layer (GDL) serves as a pivotal component governing heat transfer in proton exchange membrane fuel cells (PEMFCs). Excessive heat accumulation within the catalyst layer may lead to irreversible degradation of electrochemical activity due to accelerated catalyst sintering and carbon support corrosion. Building upon multi-modal characterization integrating micro-computed tomography (Micro-CT) and scanning electron microscopy (SEM) of GDLs, this investigation systematically deciphers the interdependent relationships between fiber architecture, sphere network topology, and compression-mediated morphological evolution through advanced computational analytics and finite element modeling. The quantified synergy elucidates microstructure-property linkages governing anisotropic thermal and gas transport phenomena. The computational findings reveal pronounced anisotropic thermal conduction characteristics within GDLs, demonstrating significantly inferior thermal transport capabilities in the through-plane (TP) direction compared to the in-plane (IP) direction. Reduced fiber length diminishes multi-directional heat dissipation, whereas GDL thickening enhances multi-directional thermal transport efficiency. Quantitative analysis demonstrates a 23-fold higher susceptibility of effective thermal conductivity (ETC) to compression ratio compared to thickness variation, conclusively establishing microstructural heterogeneity as the primary determinant of anisotropic thermal transport. Spatially resolved thermal flux mapping reveals strong geometric coupling with porosity gradients. These multiscale findings provide new design paradigms for optimizing GDL architectures through targeted manipulation of fiber-sphere coupling mechanics.