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Un modèle physique multiéchelle de la dynamique électrochimique dans une pile à combustible à électrolyte polymère – Une approche Bond Graph dimension infinie.

Abstract : In order to analyze the experimental results of impedance spectroscopy on electrodes of Polymer Electrolyte Fuel Cells (PEFC), we have developed a new knowledge model to understand the dynamic behaviour of a Membrane-Electrodes Assembly. This multiscale and mechanistic model, is based on irreversible thermodynamics and electrodynamics, and depends on the internal physical parameters, such as the effective electrode surface, the electric permittivity of the materials, the reaction kinetics and the diffusion coefficients of the reactive species.
The model results of the coupling of a microscopic scale transport phenomena description of charges (electrons and protons) through the electrode and the electrolyte thickness, a spatially distributed microscopic model of the reactant diffusion (hydrogen and oxygen) through the Nafion® layer covering the Pt/C particles, and a spatially distributed nanoscopic description of the Nafion®-Pt/C interface. This interfacial model is based on an internal description of the electrochemical double layer dynamics, coupling the transport phenomena in the diffuse layer and the electrochemical reactions and water adsorption in the compact layer.
This multiscale model introduces many couplings between different physical domains, such as diffusion-migration transport and electrochemistry. A distributed-parameter Bond Graph of this model has allowed to calculate the causalities of the different couplings, using 20-Sim®, and to give the model a modular structure (allowing to include other physico-chemical phenomena, or to be adapted and re-used in other electrochemical systems). The numerical resolution has been performed in Matlab/Simulink® coupled to Femlab® (finite elements method)
The system dynamics, depending on the current, the temperature, the reactant pressures, and the structural composition of the electrodes can be simulated. The model allows evaluating the sensitivity of impedance spectra to operating conditions and electrodes composition, and it gives access to the contributions of the different phenomena and constitutive layers.
An experimental validation of the model was carried out on a specific bench and single cell. Impedance spectroscopy measurements achieved on the test bench have allowed the validation of the proposed model and the estimation of some of its parameters.
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https://tel.archives-ouvertes.fr/tel-00110968
Contributor : Alejandro Antonio Franco Connect in order to contact the contributor
Submitted on : Thursday, November 2, 2006 - 5:21:44 PM
Last modification on : Wednesday, September 22, 2021 - 8:24:02 AM
Long-term archiving on: : Tuesday, April 6, 2010 - 6:59:41 PM

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  • HAL Id : tel-00110968, version 1

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Alejandro Antonio Franco. Un modèle physique multiéchelle de la dynamique électrochimique dans une pile à combustible à électrolyte polymère – Une approche Bond Graph dimension infinie.. Modélisation et simulation. Université Claude Bernard - Lyon I, 2005. Français. ⟨tel-00110968⟩

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