Stochastic 3D Modeling of the GDL Structure in PEMFCs Based on Thin Section Detection

Abstract

We propose a mathematical model to describe the microstructure of the gas diffusion layer ͑GDL͒ in proton exchange membrane fuel cells ͑PEMFCs͒ based on tools from stochastic geometry. The GDL is considered as a stack of thin sections. This assumption is motivated by the production process and the visual appearance of relevant microscopic images. The thin sections are modeled as planar ͓two-dimensional ͑2D͔͒ random line tessellations which are dilated with respect to three dimensions. Our 3D model for the GDL consists of several layers of these dilated line tessellations. We also describe a method to fit the proposed model to given GDL data provided by scanning electron microscopy images which can be seen as 2D projections of the 3D morphology. In connection with this, we develop an algorithm for the segmentation of such images which is necessary to obtain the required structural information from the given grayscale images.

3D analysis, modeling and simulation of transport processes in compressed fibrous microstructures, using the Lattice Boltzmann method

“…The virtual geometry of the microstructure of our transport simulations are based on the model of Thiedmann et al [51]. This model describes fiber based GDL material very well by a simple approach which makes it a promising candidate for virtual material design [56].…”

“…This model describes fiber based GDL material very well by a simple approach which makes it a promising candidate for virtual material design [56]. The fibers of paper type GDLs are almost oriented in planes which leads to the basic assumption of the Thiedmann model [51]. The fibers of the virtual geometry are created layer-wise by a 2D Poisson line process.…”

“…The stochastic fiber model was developed further by Thiedmann et al [51,52,53]. An important feature of the planar approach is the assumption of isotropy in z direction and the validation of their model against 3D tomographic data.…”

“…Its geometry was generated by the 3D stochastic model from Thiedmann et al [51] with their extended binder model [52,53]. The chosen geometry model is favorable for virtual material design because of its planar oriented structure which is nevertheless validated against 3D data.…”

“…First, Hao and Cheng created their virtual geometry from the Schladitz model [49] whereas our approach is based on the model from Thiedmann [51] and its extension regarding the binder [52,53].…”