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Arata Nakajo

Cette personne n’est plus à l’EPFL

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Publications associées (40)

Investigating Reliability on Fuel Cell Model Identification. Part II: An Estimation Method for Stochastic Parameters

Stefan Diethelm, Daniel Favrat, Jan Van Herle, Arata Nakajo, Leonidas Tsikonis

An alternative way to process data from polarization measurements for fuel cell model validation is proposed. The method is based on re- and subsampling of IV data, with which repetitive estimations are obtained for the model parameters. This way statistic ...

Wiley-Blackwell2012

Progressive activation of degradation processes in solid oxide fuel cell stacks: Part II: Spatial distribution of the degradation

Daniel Favrat, Jan Van Herle, Arata Nakajo

Solid oxide fuel cell (SOFC) stack design must yield the highest performance, reliability and durability to achieve the lowest cost of electricity delivered to end-users. Existing modelling tools can cope with the first aim, but cannot yet provide sufficie ...

Elsevier2012

Mechanical reliability and durability of SOFC stacks. Part I: Modelling of the effect of operating conditions and design alternatives on the reliability

Daniel Favrat, Jan Van Herle, Arata Nakajo

Electrochemical and mechanical aspects in solid oxide fuel cell stack must be understood to meet the reliability targets for market implementation. This study presents a stack modelling framework that combines thermo-electrochemical models, including degra ...

Elsevier2012

Mechanical reliability and durability of SOFC stacks. Part II: Modelling of mechanical failures during ageing and cycling

Daniel Favrat, Jan Van Herle, Arata Nakajo

Intricate relationships between mechanical and electrochemical degradation aspects likely affect the durability of solid oxide fuel cell stacks. This study presents a modelling framework that combines thermo-electrochemical models including degradation and ...

2012

Compilation of mechanical properties for the structural analysis of solid oxide fuel cell stacks. Constitutive materials of anode-supported cells

Jan Van Herle, Arata Nakajo, Antonin Faes

The mechanical failure of one cell is sufficient to lead to the end of service of a solid oxide fuel cell (SOFC) stack. Therefore, there is growing interest in gaining knowledge on the mechanical properties of the cell materials for stress analysis. This s ...

2012

Experimental Real-Time Optimization of a Solid Oxide Fuel Cell Stack via Constraint Adaptation

Dominique Bonvin, Zacharie Wuillemin, Arata Nakajo, Grégory François, Leonidas Tsikonis, Gene Bunin

The experimental validation of a real-time optimization (RTO) strategy for the optimal operation of a solid oxide fuel cell (SOFC) stack is reported in this paper. Unlike many existing studies, the RTO approach presented here utilizes the constraint-adapta ...

2012

Robust Real-Time Optimization of a Solid Oxide Fuel Cell Stack

Dominique Bonvin, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo, Alejandro Gabriel Marchetti, Benoît Chachuat, Leonidas Tsikonis

On-line control and optimization can improve the eﬃciency of fuel cell systems whilst simultaneously ensuring that the operation remains within a safe region. Also, fuel cells are subject to frequent variations in their power demand. This paper investigate ...

2011

Electrochemical model of solid oxide fuel cell for simulation at the stack scale. Part II: Implementation of degradation processes

Stefan Diethelm, Daniel Favrat, Jan Van Herle, Arata Nakajo, Pietro Tanasini

The degradation of the electrochemical performance of solid oxide fuel cell (SOFC) devices is a major hurdle to overcome before commercialisation. The interplay between the phenomena and the long testing times complicate the research, which highlights the ...

2011

The Effects of Dynamic Dispatch on the Degradation and Lifetime of Solid Oxide Fuel Cell Systems

Daniel Favrat, Jan Van Herle, Arata Nakajo

Understanding of mechanisms affecting degradation, durability and performance of solid oxide fuel cell (SOFC) stacks and integrated systems has become important due to increasing worldwide deployment. A novel simulation approach accounting for state-of-the ...

2011

Thermomechanical and Electrochemical Degradation in Anode-Supported Solid Oxide Fuel Cell Stacks

Arata Nakajo

The solid oxide fuel cell (SOFC) is a direct energy conversion device, which allows the production of electricity with high efficiency while maintaining pollutant emissions at a low level. It offers better fuel flexibility and lower vulnerability to impuri ...

EPFL2011

Compilation of mechanical properties for the structural analysis of solid oxide fuel cell stacks. Part II: Metallic interconnect, sealants and gas diffusion layers

Jan Van Herle, Arata Nakajo

Solid oxide fuel cell (SOFC) stacks are extremely vulnerable to mechanical failures in any of their constituents, which ultimately lead to cell cracking. Like all devices, distinct failure sequences arise from different events or design particularities. Th ...

2011

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

Stefan Diethelm, Daniel Favrat, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo

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 ...

2011

Experimental Real-Time Optimization of a Solid Oxide Fuel Cell Stack via Constraint Adaptation

Dominique Bonvin, Zacharie Wuillemin, Arata Nakajo, Grégory François, Leonidas Tsikonis, Gene Bunin

2010

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

Daniel Favrat, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo

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 ...

2009

RedOx study of anode supported solid oxide fuel cell

Aïcha Hessler-Wyser, Jan Van Herle, Arata Nakajo, Antonin Faes, David Dubois

The common technology for solid oxide fuel cells (SOFC) is based on a cermet (ceramic-metal composite) anode of nickel with yttria stabilized zirconia (YSZ), often used as the supporting structure. One of the main limitations of this technology is the tole ...

2009

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

Daniel Favrat, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo

2009

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

Daniel Favrat, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo, Minh-Tâm Luong, Nordahl Autissier

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 ...

2008

Impact of Materials and Design on Solid Oxide Fuel Cell Stack Operation

Stefan Diethelm, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo, Nordahl Autissier

Planar SOFC stack technology based on a unique concept (SOFConnex™) uses structured gas distribution layers between unprofiled metal sheet interconnects and thin Ni-YSZ anode supported electrolyte cells. The layers are flexible both in material and designa ...

2008

Design of 500 W Class SOFC Stack with Homogeneous Cell Performance

Stefan Diethelm, Jan Van Herle, Zacharie Wuillemin, Arata Nakajo, Emily Thorn, Nordahl Autissier

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 ...

The Electrochemical Society2007

Modeling of thermal stresses and probability of survival of tubular SOFC

Arata Nakajo

The temperature profile generated by a thermo-electro-chemical model was used to calculate the thermal stress distribution in a tubular solid oxide fuel cell (SOFC). The solid heat balances were calculated separately for each layer of the MEA (membrane ele ...

2006

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