Effect of channel geometry on the performance of a PEM Fuel Cell models under self-sustained oscillations in the anodic potential induced by CO poisoning

FALAGUERRA, TOMÁS; LEVITAN, DAVID; GIUNTA PABLO; CORREA PERELMUTER, GABRIEL

Foz do Iguazu

Simposio; HYPOTHESIS XIV; 2019

The main objective of this work is to analyze through a multi-dimensional model the temperature and hydrogen distribution within the fuel cell in the presence of CO impurities in the H2 inlet, and its effect on overall performance.A three-dimensional transport and thermal model of a single cell was simulated into seven domains: membrane, flow channels for hydrogen and oxygen, each platinum catalyst layer (CL), and the Gas Diffusion Layer (GDL) by COMSOL Multiphysics. This model was coupled with a 1-D in-house electrochemical double layer model. Species concentration distribution, transport phenomena and the current density were calculated simultaneously and later coupled with thermal model solved over all the computational domains. The inputs of the model are the initial cathode concentrations (N2, O2, H2O), the anode inlet mass fractions (H2, H2O, CO), cathode and anode inlet flows and pressures, the initial temperature of the system and the electric potential difference between both electrodes.The in-house anode model is built upon electrostatic, chemical kinetic and thermodynamic principles underlying the operation of a fuel cell, giving all introduced variables a physical meaning, and also featuring a novel probabilistic treatment of dipole interactions in the compact layer. Two regions of the electrochemical double layer are modelled: in the ?diffuse layer? farther away from the electrode an explicit system of differential equations is derived for the electrostatic potential and protonic concentration, while in the ?compact layer? of adsorbed molecules several modifications have been made from previous models to account for the presence of different species of dipole molecules on the electrode surface.Since the aim of this work was to study the behavior of the fuel cell under the effect of CO at the anode side, we apply the model only to this electrode. The electrochemistry of the cathode side is captured with by Butler-Volmer kinetic expressions with no further level of detail. The coupling of scales allows for the study of the interplay between the kinetics of CO-poisoned H2 oxidation, the transport of chemical species, and the effect of local temperature variations on the system. The study show how managing the operation parameters the cell have differents answers to the cell poisoning, titaH tita OH pueden adecuarse mediantes estos factores.. And selecting the adequate parameters the power obtained by the cell could be increased.