Haut PDF Proton exchange membrane fuel cell behavioral model suitable for prognostics.

Proton exchange membrane fuel cell behavioral model suitable for prognostics.

Proton exchange membrane fuel cell behavioral model suitable for prognostics.

Abstract Prognostics and Health Management (PHM) is a discipline that enables the estimation of the Remaining Useful Life (RUL) of a system and is not yet much applied to Proton Exchange Membrane Fuel Cell PEMFC. How- ever it could permit the definition of adequate conditions allowing extending PEMFC’s too short life duration. For that purpose, a model that can repro- duce the behavior of a PEMFC is needed. This paper presents a model of a PEMFC that could serve for a prognostics purpose. The model is composed of a static part and a dynamic parts that are independent. On one side, the static part is developed thanks to equations describing the physical phenom- ena and is based on the Butler-Volmer law. On the other side, the dynamic part is an electrical equivalency of physical phenomenon. The models are validated thanks to experimental data gathered in long term tests. For that purpose the parameters are successively updated based on characterization measurements (polarisation curves and EIS (electrochemical impedance spec- troscopy)). Then the results of the model are compared to the ageing data in order to evaluate if the model is able to reproduce the behavior of the fuel cell. The usefulness of this model for prognostics is finally discussed.
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Contribution of nanoclays to the barrier properties of a model proton exchange membrane for fuel cell application

Contribution of nanoclays to the barrier properties of a model proton exchange membrane for fuel cell application

(2) Laboratoire de Chimie Industrielle, Institut de Chimie B6, University of Liège, Sart Tilman, B-4000 Liège, Belgium Abstract Direct methanol fuel cells (DMFCs) that use a proton exchange membrane (PEM) as electrolyte, is a promising alternative source of energy for the future. However, methanol crossover from the anodic side to the cathodic one is a major problem in DMFC. Proper dispersion of layered silicates within the fuel cell membrane has been proposed as a strategy for improving the barrier properties of the membrane. The validity of this approach has been tested in case of a model membrane consisting of phosphotungstic acid doped poly(vinyl alcohol). A solvent casting technique has been used, which allows the nanofiller to be delaminated by an ultrasonic pre- treatment, as confirmed by TEM and XRD analysis. The layered silicates have a favourable impact on the methanol permeability, whose the decrease overcompensates some loss in ionic conductivity.
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Model-Based Control of a Continuous Coating Line for Proton Exchange Membrane Fuel Cell Electrode Assembly

Model-Based Control of a Continuous Coating Line for Proton Exchange Membrane Fuel Cell Electrode Assembly

4. Linear-Quadratic-Gaussian Controller The model presented in the previous section is far from perfect, and neither will be the measurements taken from the process. A linear-quadratic-Gaussian (LQG) approach, a combination of a Kalman Filter and a linear quadratic regulator (LQR), is chosen for real-time control under uncer- tainties. The model is converted from a Lagrangian reference frame to an Eulerian reference frame, and method of lines is applied to convert the resulting partial differential equations into a set of ordinary differential equations. These differential equations are used to obtain the nominal operating condi- tions, and then these conditions are used to linearize the system. The linearized state-space model is used to design the linear quadratic regulator and Kalman filter.
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A general model for air-side proton exchange membrane fuel cell contamination

A general model for air-side proton exchange membrane fuel cell contamination

[48–50] . In another kinetic model study [51] , both associative and dissociative mechanisms were analyzed. In recent years, many theoretical explorations of the ORR mech- anism using quantum mechanic methods have been reported, as shown in the review articles [52,53] . These studies supplied information on each elementary step, such as activation ener- gies, reaction energies, and reversible potentials. Anderson and co-workers [54,55] investigated the activation barrier for each of the following electron transfer steps:

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Pore network modelling of condensation in gas diffusion layers of proton exchange membrane fuel cell

Pore network modelling of condensation in gas diffusion layers of proton exchange membrane fuel cell

However, the simulations at the rib–channel scales must still be improved before being in a position to really perform studies aiming at improving the design of GDL or more generally better control the ageing problem. One must develop a model coupling the pore network model of the GDL to models describing the transfers and the other phenomena of importance (electro- chemical reactions, mechanical deformations, etc) in the other components of the cell. To just mention one issue, oxygen transfer was not considered in our simulations since the current density distribution at the GDL inlet was an input in the simulations and not a result of the computation. Predicting the current density distribution is of course desirable. Such a modeling coupling the components should be extended so as to take into account not only the cathode but the anode and the membrane as well. Such a coupled modeling approach could permit to fully clarify the water transfer mechanisms. This work puts a strong emphasis on the condensation process with the assumption that the water enters the GDL essentially in vapour form. Although there is no doubt in our opinion that condensation is a major mechanism, the situation is proba- bly subtler than considered in the present work. For instance, it is likely that condensation can
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Fault Detection and Isolation for Proton Exchange Membrane Fuel Cell Using Impedance Measurements and Multiphysics Modeling

Fault Detection and Isolation for Proton Exchange Membrane Fuel Cell Using Impedance Measurements and Multiphysics Modeling

Abstract This study proposes a model-based tool for fault detection and isolation for Proton Exchange Membrane Fuel Cell (PEMFC) for embedded applications that is robust to behaviour changes due to power demand fluctuations and stack ageing. The considered faults are the abnormal operating conditions that can shorten the fuel cell lifetime. The fault detection approach is based on residual generation using both voltage and high frequency resistance measurements and thus combining the advantages of knowledge-based model and EIS diagnosis approaches. To that end, a multi-physics fuel cell model has been used. This model computes not only the stack voltage but also the high frequency resistance in dynamic conditions. Additionally, the model is modified to take into account the ageing of the fuel cell. Validation is carried out on experimental characterizations during 1,000 hours ageing. The results on a new fuel cell stack show a score of 91% for fault isolation. However, this score drops dramatically while the stack is ageing. Finally, thanks to ageing modelling, diagnosis performances remain reliable during fuel cell stack ageing.
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Numerical predictions of transport phenomena in a proton exchange membrane fuel cell

Numerical predictions of transport phenomena in a proton exchange membrane fuel cell

This is because current is more evenly distributed across the mem- brane for the 1D model; while the actual situation is such that the current density varies locally from the regions located near the air channel to those adjacent to the ribs, depending on the rate of diffusion of oxygen 共i.e., concentration兲, which affects the gradi- ent of the local potential field. For the case considered here, the local variations of current density are relatively small and good agreement between the two methods is seen in Fig. 2. Local cur- rent density variations depend not only on the mass-transfer con- ductivities 共exchange coefficients兲, but also on geometric factors, such as the thickness of the layers and the ratio of channel width to that of the ribs.
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Numerical analysis of water transport through the membrane electrolyte assembly of a polymer exchange membrane fuel cell

Numerical analysis of water transport through the membrane electrolyte assembly of a polymer exchange membrane fuel cell

Bernardi and Verbrugge 关12兴 developed the hydraulic model with assumptions that the membrane is fully hydrated with liquid water. They analyzed the effects of different operating conditions on water balance in fuel cells. However, this model is not suitable for a partially dry membrane. Recently, Janssen 关13兴 developed a two-dimensional phenomenological model based on concentrated solution theory to describe the transport of water in the mem- brane, and of water vapor and liquid water in the electrodes. This model gave a clear description of water transport in a partially dry membrane as well as in a fully hydrated membrane, but it was a water transport model only and did not couple with a cell model to thoroughly understand the effect of water transport on cell perfor- mance. Therefore, to further understand water transport through the membrane electrolyte assembly 共MEA兲 of a PEM fuel cell, a model should include two-phase transport in the electrodes and gas diffusion layers, describe fully water transport in a cell oper- ating with saturated and unsaturated gases, and couple with a cell model.
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Highly fluorinated comb-shaped copolymer as proton exchange membranes (PEMs): fuel cell performance

Highly fluorinated comb-shaped copolymer as proton exchange membranes (PEMs): fuel cell performance

) and the sluggish oxidation kinetics of methanol at the anode pose serious problems for the commercialization of DMFC technology. As a result, a substantial amount of current research is aimed at designing and developing higher-temperature and lower- cost alternative polymer materials based on non-fluorinated or partially fluorinated polymeric systems with reduced methanol permeability while maintaining high proton conductivity [2] . The majority of this work is based on non-fluorinated, polyaromatic- based condensation polymers that contain ionic functionality in the form of sulfonic acid groups located along the polymer back- bone. Generally, these polymers can achieve suitable conductivities only at high ion-exchange capacities (IECs), resulting in high water uptake and large membrane dimensional changes that are unsuit-
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Global Parameters Sensitivity Analysis and Development of a Two-Dimensional Real-Time Model of Proton-Exchange-Membrane Fuel Cells

Global Parameters Sensitivity Analysis and Development of a Two-Dimensional Real-Time Model of Proton-Exchange-Membrane Fuel Cells

This paper presents a 2-D real-time modeling approach for a proton-exchange-membrane fuel cell (PEMFC). The proposed model covers multi-physical domains for both fluidic and electrochemical features, which considers in particular the flow field geometric form of fuel cell. The characteristics of reactant gas convection in the serpentine gas pipeline and diffusion phenomenon through the gas diffusion layer (GDL) are thoroughly considered in fluidic domain model. In addition, a three levels iterative solver is developed in order to accurately calculate the implicit spatial physical quantities distribution in electrochemical domain. Moreover, the proposed 2-D real-time modeling approach uses a numerical method to achieve a fast execution time, and can thus be further easily applied to any real- time control implementation or online diagnostic system. After experimental validation under different fuel cell operating conditions, an iterative Least Angle Regression (LAR) method is used to efficiently and accurately perform the global parameters sensitivity analysis based on Sobol definition. The online analysis results give an insight into the influences of modeling parameters on fuel cell performance. The effect of interactions between parameters’ sensitivities is especially investigated, which can provide useful information for degradation understanding, parameters tuning, re-calibration of the parameters and online prognostic.
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Proton Exchange Membrane Electrolyzer Emulator for Power Electronics Testing Applications

Proton Exchange Membrane Electrolyzer Emulator for Power Electronics Testing Applications

In recent years, research on hydrogen technologies has intensified to meet challeng‐ ing issues and to make easier their large‐scale dissemination and integration for different  applications (transportation, energy storage, power‐to‐gas, and industry) [9–12]. For fuel  cell (FC) applications, intensive research has been carried out for control and fault recon‐ struction  purposes  such as  the  enhancement  of the maximum FC net  power through a  sliding mode variable structure control [13], the observation of the system states based on  a second‐order sliding mode observer [14], the minimization of the hydrogen consump‐ tion  through  a  state  machine  control  applied  to  an  FC/supercapacitor  hybrid  tramway  [15],  and  the  optimization  of  the  FC  net  power  and  the  decrease  of  oxygen  starvation  through a model‐based robust control [16]. In these works, a real‐time FC emulation sys‐ tem has been employed to validate the developed control strategies. 
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Pore network modelling of condensation in gas diffusion layers of proton exchange membrane fuel cells

Pore network modelling of condensation in gas diffusion layers of proton exchange membrane fuel cells

into account the impact of liquid water on thermal conductivity and the consideration of the latent heat transfer. Since the gas mixture on the cathode side is made of air, oxygen and water vapour, the modelling of the diffusion transport could be improved by fully considering the gas phase as a ternary mixture. The oxygen transport does not play any role in the model consid- ered in the present paper. This is so because we consider the cur- rent density distribution at the GDL inlet as an input data. Note in passing that the current density was spatially uniform at the GDL inlet in our simulations. However, tests with non-uniform dis- tributions (lower at the entrance of rib region and greater at the entrance of channel regions as well as conversely) did not lead to significantly different results from those reported in the present paper. A more satisfactory solution would be to develop a mod- elling coupling the transfers in the GDL with the transfers in the catalyst layer (and the MPL). In such a model, the current density distribution would be an output of the model and not an input. Furthermore, this would enable one to predict the impact of liquid water formation on the fuel cell performance, i.e. the polarization curve. Work in this direction in progress. The model presented and discussed in the present paper is nevertheless a key element for such a significantly more involved modelling.
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Effect of open circuit voltage on degradation of a short proton exchange membrane fuel cell stack with bilayer membrane configurations

Effect of open circuit voltage on degradation of a short proton exchange membrane fuel cell stack with bilayer membrane configurations

Given the current research developments in PEM fuel cell degra- dation under OCV, further understanding is certainly required, especially regarding the correlations between various causes of degradation. Experimental investigations into the degradation mechanisms of different components and their complex inter- dependence with operating conditions are increasingly being correlated with modeling activities to gain improved understand- ing. For example, based on a theoretical model of mixed potential, Vilekar and Datta [9] suggested that both hydrogen crossover and the resulting oxygen reduction reaction (ORR) overpotential at the cathode play critical roles in OCV. More recently, Yoon and Huang [10] have carried out an experiment at low relative humid- ity and high temperature under OCV. They exposed the fuel cell (with homemade bilayer MEAs) to OCV under two gas feeding con- ditions, hydrogen/air and 4% hydrogen/oxygen. The bilayer MEA was separable into two pieces of one-side coated membranes to facilitate the corresponding analysis. In addition to in situ elec- trochemical analysis, they performed postmortem examination, including uniaxial mechanical testing, infrared (IR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray
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Data-driven Prognostics of Proton Exchange Membrane Fuel Cell Stack with constraint based Summation-Wavelet Extreme Learning Machine.

Data-driven Prognostics of Proton Exchange Membrane Fuel Cell Stack with constraint based Summation-Wavelet Extreme Learning Machine.

1. INTRODUCTION Fuel cell (FC) technology is an alternate source of renewable energy that has the power to change the world with a clean energy for the future. A FC can generate electricity as long as fuel is supplied. Among different types of Fuel Cells, the Proton Exchange Membrane Fuel Cell (PEMFC) is a promising technology for the use of mobile, stationary and transportation applications. Mainly, due to the advantages like: high power density, rapid startup, light weight, low temperature [1]. However, the main barriers in commercialization of PEMFCs technology are long-term performances, durability, and high production and maintenance costs [2]. PEMFC suffers from a limited life span [3], and there is a need to increase its durability for large scale industrial deployment. In other words, opimization of FC service and minimization of its life cycle costs/ risks require continuous monitoring of aging process and accurate prediction of life time at which it will be unable to perform the desired functionality. In this context, Prognostics and Health Management (PHM) of FC is an emering discipline that has the potential for improving the use, support and life management of a FC system that consist of a stack and several supporting components. However, repairing the FC stack requires spealist attention. The parts of FC are generally manufactured with expensive and in some cases scarce materials. Ensuring that FC stack is in service for as long as possible is of vital importance [4], which highlights the requirement prognostics. Therefore, leaving aside ancillary systems, the dicussions in this paper are limited to prognostics of FC stack particularly with a data-driven approach.
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Proton Exchange Membrane Fuel Cell Operation and Degradation in Short-Circuit

Proton Exchange Membrane Fuel Cell Operation and Degradation in Short-Circuit

Zhao and Burke [10] compare FC/UC hybridization using different powertrain configurations, and power split control strategies. Based on fuel economy/consumption and component/system efficiency for the same size vehicles having the same road load characteristics, simulation results demonstrate that passive hybrid architecture increases the global efficiency mainly because of the elimination of the power electronics energy losses. Hinaje et al. [12] propose the implementation of a PEMFC as a current source controlled by hydrogen flow rate. The work mainly focuses on mass transport in the electrodes to describe the transient electrical behavior. This is done for FC/UC passive hybridization and PEMFC short–circuit. Fuel cell degradation has not been revealed after this experience. Recently, Morin et al. [5] studied FC/UC passive hybridization static and dynamic properties at the scale of each cell of a fuel cell stack. Yalcinoz [15] propose control strategies for fuel cell/ultra capacitors passive hybridization for portable applications, in which a dynamic model of the PEMFC are evaluated under various load conditions. The UC supplies the load variations and transient power demand of a laptop.
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Proton exchange membrane fuel cell remaining useful life prognostics considering degradation recovery phenomena

Proton exchange membrane fuel cell remaining useful life prognostics considering degradation recovery phenomena

of data to develop complete models for behavior, aging, and degradation. Moreover, data for different applications and different operating conditions should be gathered to ensure the generality and the transferability of the developed approaches. Approaches based on machine learning techniques have been proposed: the method in ( Morando et al. 2017 ) requires a large data series and a long time for tuning of several model parameters. The work in ( Javed et al. 2016 ) has overcome the data limitation, but it needs state constraints to guarantee the RUL predictions. For approaches involving a model, the modeling level depends on the level of understanding of PEMFC behaviors. For some not-well-understood behaviors, e.g. the recovery phenomena, it can be interesting to rely on empirical (based on experimental data) modeling of degradation trends to improve the precision of final prediction. When feasible, a physics- based behavioral model to reproduce PEMFC aging behavior can be proposed, as in ( Lechartier et al. 2015 ). The model is composed of a static part and dynamic parts that are independent. The static part is developed thanks to equations describing the physical phenomena and is based on the Butler-Volmer law that takes into account the activation loss at the cathode and the anode. In ( Bressel et al. 2016 ), the PEMFC RUL prediction subjected to a µ-CHP profile is carried out by using an Extended Kalman Filter (EKF) throughout a physics-based voltage model.
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Modelling and numerical simulation of water transfer in Proton Exchange Membrane Fuel Cells

Modelling and numerical simulation of water transfer in Proton Exchange Membrane Fuel Cells

fact that the reactant gas poorly diffuses in this region even when the GDL is dry owing to the longer diffusion path compared to the straight paths in the regions below the half-channels. In other words, the reactant gas transport predominantly occurs in the regions of the GDL below the channels and much less in the region below the rib. The significant lower values of τ for the two other regimes is thus a consequence of the liquid water presence in the regions below the two half channels. Another striking observation is the impact of the wettability configuration as regards the pure liquid injection and mixed regimes. In the random configuration, the gas access is improved when f increases in the pure liquid injection regime. The impact is significant since there is about a factor 2 between the lower values of τ (f ∼20%) and the greater values (f ∼80%). As can be seen from Fig.5.4 and Fig.5.7, the variation of τ with f is well correlated with the variation of the overall liquid water saturation. When the saturation increases with f , then τ decreases with f and conversely. However, it can be seen that τ is higher for f = 100% than for f =0% while the overall saturations are close (Fig.5.4). This is fully consistent with the impact of f on the pattern depicted in Fig.5.3. Thus, the loss of hydrophobicity for this regime and this wettability configuration is globally more beneficial than detrimental. The conclusion is exactly opposite for this regime with the non-uniform wettability configuration. This is a consequence of the flooding of the central region in this case which severely limits the gas access when f is sufficiently high. Although the impact of f in the random wettability configuration is less clear for the mixed regime, the conclusion regarding the impact of the wettability configuration for this regime is somewhat similar since again the reactant gas access is severely affected when f is sufficiently high in the non-uniform wettability configuration. This highlights the fact that the impact of the wettability variations can be subtle.
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Effects of open-circuit operation on membrane and catalyst layer degradation in proton exchange membrane fuel cells

Effects of open-circuit operation on membrane and catalyst layer degradation in proton exchange membrane fuel cells

a b s t r a c t Durability issues have been attracting a great deal of attention in hydrogen/air proton exchange mem- brane (PEM) fuel cell research. In the present work, membrane electrode assembly (MEA) degradation under open circuit (OC) conditions was carried out for more than 250 h. By means of several on-line elec- trochemical measurements, the performance of the fuel cell was analysed at different times during the degradation process. The results indicate that structural changes in the PEM and catalyst layers (CLs) are the main reasons for the decline in performance during OC operation. The results also show that degra- dation due to platinum oxidation or catalyst contamination can be partially recovered by a subsequent potential cycling process, whereas the same cycling process cannot recover the membrane degradation. Crown Copyright © 2009 Published by Elsevier B.V. All rights reserved.
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Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

[33] Hofmann MA, Ambler CM, Maher AE, Chalkova E, Zhou XY, Lvov SN, Allcock HR. Synthesis of polyphosphazenes with sulfonimide side groups. Macromolecules 2002;35:6490–3. [34] Liu B, Kim DS, Guiver MD, Kim YS, Pivovar BS. Sulfonated poly(arylene ether)-type polymers as proton exchange mem- branes: synthesis and performance. In: Peinemann K-V, Nunes SP, editors. Membranes for energy conversion. Weinheim: Wiley–VCH Verlag GmbH & Co. KgaA; 2008. p. 1–45.

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Designing the 3D Architecture of PGM-Free Cathodes for H 2 /Air Proton Exchange Membrane Fuel Cells

Designing the 3D Architecture of PGM-Free Cathodes for H 2 /Air Proton Exchange Membrane Fuel Cells

5 to achieve a high active-site density in FeNC, while the fibrous geometry is beneficial for enhanced mass-transport properties in catalytic layers. In addition, the macroporous voids between CNFs can also act as water drains during PEMFC operation, mitigating flooding issues in micro- and mesopores. Despite promising results, two critical aspects related to the use of electrospinning have been under-investigated in previous studies on the co-electrospinning of ZIF-8 and a polymer carrier as a strategy for preparing FeNC catalysts. The first critical aspect concerns the Fe speciation after pyrolysis, and the lack of a clear view whether the same or different Fe speciation was obtained compared to the well-established synthesis approaches involving ZIF-8 powder. 32 The second critical aspect relates to tuning the crystal size of ZIF-8 smaller than the polymer fibre diameter for i) improved O 2 accessibility of active sites in the
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