Capturing the Morphology of the Micro-Porous Layer Using a Stochastic Approach
Numerical simulation is one of the most promising alternatives to systematically characterize the MPL and its effective transport properties. We have previously established and validated a numerical framework for the GDL1. In this work, we propose a stochastic method to generate the physical structure of the MPL material. The model utilizes material specifications such as porosity, size of the particles and PTFE loading as input for structure generation. The model also incorporates parameters to recreate the morphology of an actual structure, such as the clustering and the agglomeration of the particles and the location of the PTFE. This novel technique allows generating a realistic porous media that is validated against experimental data. The results show very good agreement with the measured pore size distribution of a standard MPL material sample. The validated 3D structure is then used to compute the effective transport properties2 that are also in good agreement with the limited data available in the literature3. The model is subsequently applied to investigate the effect of certain parameters on the structure and thus on the effective properties. The results of the study provide some insight on how the MPL manufacturing process and particle size can be tuned for specific target properties. Overall, the stochastic modeling framework is intended to become a useful design tool for simulation and design of next generation MPL materials.
This research was supported by Ballard Power Systems and the Natural Sciences and Engineering Research Council of Canada through an Automotive Partnership Canada (APC) grant. We highly appreciate the support form Professor Ned Djilali’s group at the University of Victoria. This research made use of computing resources provided by WestGrid and Compute/Calcul Canada.
1. M. El Hannach, and E. Kjeang, J. Electrochem. Soc., under review
2. K. J. Lange, P.-C. Sui, and N. Djilali, Commun. Comput. Phys., 14, 537–573 (2013).