Membrane degradation model for 3D CFD analysis of fuel cell performance as a function of time

Abstract

Available online xxxKeywords: Polymer electrolyte fuel cell Nafion degradation Modelling Computational fluid dynamics Local operating condition a b s t r a c t The paper describes a development of a degradation model, which enables to predict timedependent changes in performance of a polymer electrolyte fuel cell. The developed model consists of two main parts: 1) a new semi-empirical model taking into account changes in physico-chemical properties of a polymer electrolyte membrane operating in the fuel cell, 2) a validated CFD model computing the 3D performance of the cell. In the semi-empirical model, the degradation rates of the membrane thickness and conductivity depend on the oxygen crossover rate. The acid group concentration is calculated from the membrane conductivity based on the percolation theory approach. The gas diffusion coefficients are modelled empirically as a function of the membrane thickness. The model of the membrane degradation is coupled with the CFD model and applied to analyse the cell behaviour as a function of time. The simulation shows that the cell current density decreases faster with lowering relative humidity and increasing temperature. The in-plane degradation of the membrane is non-uniform and depends on the local operating condition.

Advanced CFD Analysis of an Air‐cooled PEM Fuel Cell Stack Predicting the Loss of Performance with Time

“…The derivation of Eq. 47 32 is based on the experimental data from 33. The membrane parameters $ \psi $ at an operating time t are calculated via …”

CFD Simulation of an Industrial PEM Fuel Cell with Local Degradation Effects

“…In the past two decades, CFD models have been extensively developed and applied to investigate factors influencing durability and degradation rates of materials determining the lifetime of fuel cells [10,[20][21][22][23][24][25][26][27]. Gidwani et al [20] studied durability and degradation of PEM fuel cells with a focus on carbon corrosion at electrodes.…”

“…Using CO-tolerant catalysts (PtRu/C) led to improvement of the cell performance at low temperature. In [24] and [25] the PEM fuel cell simulation package developed by AVL List GmbH was coupled with a semi-empirical degradation model describing the dependency of material parameters on operating conditions. The degradation rates of the membrane thickness and conductivity were dependent on the oxygen crossover rate, a relation which is additionally confirmed by the findings of the present work.…”

“…In the past two decades, CFD models have been extensively developed and applied to investigate factors influencing durability and degradation rates of materials determining the lifetime of fuel cells , . Gidwani et al.…”

“…25 show several 3D simulation results for the aged cell at an approximate voltage of 0.48 V for all three…”