Latest news

On 2nd April 2019, Kamil Mrozewski defended his thesis. Awarded by INP Toulouse, his work was supervised by Laplace, the GEET doctoral school and IRT Saint Exupéry.
The high quality and the relevance of Kamil’s thesis contributed to get significant results as a part of Fuchya project.

The aeronautical R&D activities are currently shaped by the issues associated with the pollutant-rich nature of the industry and the natural evolution towards more effective and sustainable technologies. In this regard, the development of more electric aircraft would contribute to reducing fossil fuel consumption by incorporating alternative sources and converters of energy, such as FCs. However, a FC system would have to comply with particular reliability and safety constraints, especially as the aeronautical environment is not very indulgent: abundant pressure and temperature cycling as well as mechanical loads, varying both in frequency and amplitude, in all three dimensions. Vibrations and shocks can in particular lead to a sudden or gradual loosening of the FC, thus degrading its performance, and possibly provoking a gas leak. It therefore seems important to be able to monitor the tightening state of a FC over time, ideally in a non-intrusive manner.

Results reported in the literature indicate that the quality of the mechanical tightening of a FC assembly might be assessed through its ohmic resistance (Rohm), more precisely through its electronic part (Re-, formed by the bulk resistances of FC layers and the interfacial contact resistances). In nominal operating conditions, the second and more dominant part of Rohm – the protonic resistance (RH+, formed by the membrane and ionomer resistances) – does not depend on clamping pressure. This amalgamation of resistances of different natures prevents an easy extraction of Re- without the use of invasive sensors and thus an estimation of the quality of the mechanical tightening of a FC assembly.

This thesis proposes an in situ preventive diagnosis method that is capable of detecting the degradation of clamping conditions of a FC through the modelling of its ohmic resistance. A theoretical study is performed and demonstrates that the RH+ and Re- resistances can be separated from the total Rohm, based on their temperature dependence. The proposed method is verified with experimental data generated during the characterization of low and high temperature Polymer Electrolyte Membrane (PEM) single cells. Although some differences between the values identified by the algorithm and those reported in the literature are observed, they correctly depict the behavior of the mechanical tightening of the tested FCs. Overall, the results are encouraging in the aim of monitoring the quality of mechanical tightening of a FC through the evolution of RH+ and Re-.

Melika HINAJE	Rapporter	Professor at GREEN, Université de Lorraine
Denis CANDUSSO	Rapporter	Researcher at IFSTTAR/SATIE/FCLab
Yann BULTEL	Examiner	Professor at LEPMI, Grenoble INP
Catherine CADET	Examiner	Lecturer (HDR) at GIPSA-lab, UGA
Julien D’ARBIGNY	Invited	Engineer at Safran Aerotechnics
Théophile HORDÉ	Invited	Technical Manager at Safran Power Units
Fabio COCCETTI	Invited	Head of Components Modelling and Reliability Competence Centre, IRT Saint Exupéry
Christophe TURPIN	Thesis Director	Researcher at LAPLACE, Toulouse INP
Antoine PICOT	Thesis Co-Director	Lecturer at LAPLACE, Toulouse INP

“Determination of Mechanical Tightening of a Single PEM Cell via Electrical Measurements (Application in Aircraft)” K. MROZEWSKI, A. PICOT, O. RALLIERES, C. TURPIN, G. GAGER, J. D’ARBIGNY, T. HORDE, L. PRISSE – 7th International Conference on Fundamentals and Development of Fuel Cells (FDFC 2017) – Stuttgart, Germany

“High-level diagnostic methods of FC operational availability: Assessing the quality of mechanical tightening of single LT-PEM and HT-PEM cells via electrical measurements” K. MROZEWSKI, A. PICOT, O. RALLIERES, C. TURPIN, G. GAGER, J. D’ARBIGNY, T. HORDE, L. PRISSE – Plenary meeting of the Groupement de Recherche “Hydrogène, systèmes et Piles à Combustible” (GdR HySPàC 2017) – Limoges, France

“Determination of Mechanical Tightening of Single LT-PEM and HT-PEM Cells via Electrical Measurements” K. MROZEWSKI, A. PICOT, O. RALLIERES, C. TURPIN, G. GAGER, J. D’ARBIGNY, T. HORDE, L. PRISSE – 12th International Conference on Modelling and Simulation of Electric Machine, Converters and Systems (ELECTRIMACS 2017) – Toulouse, France

“Procédé et dispositif d’évaluation de l’état de serrage d’une pile à combustible”

The request of the patent was lodged on 14/01/2019 under number FR1900318, with these inventors:

• IRT Saint Exupéry, MROZEWSKI Kamil
• Toulouse INP / LAPLACE, PICOT Antoine
• CNRS / Toulouse INP / LAPLACE, TURPIN Christophe
• Zodiac Aerotechnics, D’ARBIGNY Julien