Publications by Zacharie Wuillemin

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Structural stability issues in planar solid oxide fuel cells arise from the mismatch between the coefficients of thermal expansion of the components. The stress state at operating temperature is the superposition of several contributions, which differ depe ...

Solid Oxide Fuel Cells (SOFCs) are likely candidates for electricity production with high efficiency and promise reasonable fuel tolerance. While fuel impurities are known anode poisons, less attention is brought to air-purity, especially to air-side conta ...

It is now common knowledge that flow uniformity within repeat-elements - as well as among them in stack configuration - is of major importance for the performance and reliability of solid oxide fuel cells (SOFCs). At first, a design optimization of the configuration of the gas diffusion layer (GDL) may appear sufficient to ensure that the fuel is converted uniformly. However, in practice, the precision of assembly and manufacturing tolerances are known to have a large impact on the quality of the fuel distr

The properties of sealing materials are important for the performance and reliability of solid oxide fuel cells (SOFCs). Even if the properties of a sealing material can be studied separately, it remains difficult to quantify the effect of an imperfect sea ...

There still exists a large gap between simulation work and industrial applications in the context of control and optimization of solid-oxide fuel-cell (SOFC) systems. In an effort to bridge this gap, this study describes the experimental implementation of ...

Structural stability issues in planar solid oxide fuel cells (SOFC) arise from the mismatch between the coefficients of thermal expansion (CTE) of the components. The stress state at operating temperature is the superposition of several contributions, which differ depending on the component. First, the cells undergo residual stresses due to the sintering phase during the manufacturing process. Furthermore, the load applied during the assembly of the stack to ensure the electric contact and flatten the cells

The properties of sealing materials are important for the performance and reliability of solid oxide fuel cells (SOFC). Even if the properties of a sealing material can be studied separately, it remains difficult to quantify the effect of an imperfect seal ...

Lifetime prediction and improvement of solid oxide fuel cell (SOFC) devices require a reliable electrochemical model that supports the implementation of degradation phenomena. This study comprises two parts. This Part I describes the calibration of an elec ...

In order to characterize a new SOFC stack design, to investigate degradation processes and to validate models, a diagnostic test station was designed and realized. It allows to characterize repeat-elements locally by measuring the local potential, current density and temperature over the active area. The active area is segmented in 18 small electrically insulated measurement points (segments), in addition to a main segment. The profile of current density was investigated up to an average of 0.6A/cm2 and 67%

The experimental implementation of real-time optimization (RTO) to a commercial solid-oxide fuel-cell (SOFC) system is reported in this paper. The goal of RTO is to maximize the system efficiency at steady state subject to several operating constraints. Th ...

Our planar SOFC stacking technology uses unprofiled metallic interconnects (MIC) and thin cells of tape cast anode supported YSZ. The key element is the gas diffusion layer (GDL) between cell and MIC, which consists of so-called SOFConnex™. Using square ce ...

Spatially resolved analyses, by energy-dispersive X-ray spectroscopy (EDS) scanning electron microscopy (SEM), allowed the quantification of exogenous Si contamination in a solid oxide fuel cell (SOFC) cathode after operation. The Si quantification, taking ...

To improve the industry benchmark of solid oxide fuel cell (SOFC) systems, we consider anode off-gas recirculation (AOR) using a small-scale fan. Evolutionary algorithms compare different system design alternatives with hot or cold recirculation. The syste ...

A CFD model was developed to predict with accuracy the local electrochemical performance in an operating solid oxide fuel cell. A particular focus was given on the study of performance limitations and degradation sources caused by the design of the fuel cell, by the choice of materials and components, or by improper operating points. The model is used to understand typical degradation effects observed on stacks tested in collaboration with HTCeramix - SOFCpower. The model is able to predict several degradat

The locally-resolved degradation behavior was studied during 1900 hours in an SOFC repeat-element. In-situ measurements of local electrochemical performance were made on 18 locations over a segmented anode-supported cell. The evolution of local current densities, overpotentials and area-specific resistances was studied, showing a reorganization of the electrochemical reaction with time. The extent and the spatial distribution of degradation were established for different electrochemical reactions steps usin

The increasing quality and durability of Solid Oxide Fuel Cells (SOFC) state-of-the-art materials renders the long-term testing of fuel cells difficult since considerably long equipment times are needed to obtain valuable results. Moreover, reproducibility issues are common due to the high sensitivity of the performance and degradation on the testing conditions. An original segmented cell configuration has been adopted in order to carry out four tests in parallel, thus decreasing the total experimental time

This work aims to compare the effect of combined chromium and sulfur contaminating conditions to the Cr contamination alone on the Cr poisoning mechanisms in (La,Sr)MnO3-(Zr,Y)O-2 solid oxide fuel cell (SOFC) cathodes. Whereas Cr2O3 and (Cr,Mn)(3)O-4 are f ...

Results on solid oxide fuel cell stacks tested at 800° C with H2 fuel and using planar Ni-zirconia anode supported cells, 80x80x0.2 mm in size, are presented. Modeling and numerical simulation is used to interpret observed results and develop improved desi ...

Zacharie Wuillemin

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Simulation of thermal stresses in anode-supported solid oxide fuel cell stacks. Part I: Probability of failure of the cells

Air Side Contamination in SOFC Stack Testing

Impact of Random Geometric Distortions on the Performance and Reliability of an SOFC

Modeling and Study of the Influence of Sealing on a Solid Oxide Fuel Cell

Real-time optimization of an experimental solid-oxide fuel-cell system

Air Side Contamination in Solid Oxide Fuel Cell Stack Testing

Simulation of Thermal stresses in anode-supported solid oxide fuel cell stacks

Modeling and study of the influence of sealing on a solid oxide fuel cell

Electrochemical Model of Solid Oxide Fuel Cell for Simulation at the Stack Scale I. Calibration Procedure on Experimental Data

Investigation of Local Electrochemical Performance and Local Degradation in an Operating Solid Oxide Fuel Cell

Fast RTO Applied to a Commercial SOFC System

Design of 500 W Class SOFC Stack with Homogeneous Cell Performance

Glass-Forming Exogenous Silicon Contamination in Solid Oxide Fuel Cell Cathodes

Modeling and Designing of a Radial Anode Off-Gas Recirculation Fan for Solid Oxide Fuel Cell Systems

Modeling of Local Cell Degradation in Solid Oxide Fuel Cells: Cumulative Effect of Critical Operating Points

Locally-Resolved Study of Degradation in a SOFC Repeat- Element

Simulation of thermal stresses in anode-supported solid oxide fuel cell stacks. Part II: Loss of gas-tightness, electrical contact and thermal buckling

Segmented cell testing for cathode parameter investigation

Combined Cr and S poisoning in solid oxide fuel cell cathodes

Modeling and experimental validation of solid oxide fuel cell materials and stacks