Simulazione dettagliata della resistenza ohmica per celle IPSOFC

Simulazione dettagliata della resistenza ohmica per celle IP-SOFC Laura Repetto, Paola Costamagna Genova, 12 Dicembre 2007 Università di Genova Dipartimento di Ingegneria Chimica e di Processo ‘G. B. Bonino’

Summary of the work carried out AIM Detailed simulation of the ohmic losses of the IP-SOFC (Integrated Planar-Solid Oxide Fuel Cell) and calculation of the ohmic resistance. HOW Numerical solution of partial differential equations through the commercial software Comsol Multiphisycs. WHAT I DID ü Development of a physical / matematical model ü Model validation ü Use of the model to predict the IP-SOFC performance Genova, 12 Dicembre 2007

Solid Oxide Fuel Cell (SOFC) is a particular Fuel Cell characterized by the use of a ceramic electrolyte (a solid oxide). The electrochemical reactions are: Cathodic reaction Anodic reaction Tubular geometry Planar geometry Genova, 12 Dicembre 2007

IP-SOFC The IP-SOFC concept is a proprietary SOFC design currently developed by Rolls-Royce Fuel Cell Systems Ltd. tubular geometry IP-SOFC geometry + Mechanical stability of the cell components e- planar geometry Lower manufacturing costs e- Simplified IP-SOFC geometry NOTE: the electrochemical reactions on cathodic and anodic side have not been simulated Genova, 12 Dicembre 2007

Model equations Genova, 12 Dicembre 2007

Comsol Multiphysics • Comsol Multiphysics is a modelling package able to simulate the physical process described with partial differential equations (PDEs). • It is based on the finite elements method (FEM). • It is an interactive environment. • It provides specialised modules with predefined PDEs for different scientific fields (in my work the Electromagnetics Module and in particular the Conductive Media DC section has been used). • These modules use standardized terminology and material libraries. Usually it is not necessary to write the equations since they are included in the modules; it is sufficient to describe the physical/mathematical properties of the problem (materials conductivity, continuity of the solution along the interfaces etc) Genova, 12 Dicembre 2007

Comsol results (1) Norma della densità di corrente nell’elettrolita Femlab Matlab Genova, 12 Dicembre 2007

Comsol results (2) e- e- Colour map of the Voltage Genova, 12 Dicembre 2007

Comsol results (3) e- e- Streamlines and colour map of the current density norm Genova, 12 Dicembre 2007

Model predictions Model validation Model prediction Geometry optimisation Design the optimal geometry in order to increase the performance of the cell and, at the same time, to lower manufacturing costs. Work carried out: ü study of the current path in the electrolyte Secondary interconnect (SIC) study Design the optimal geometry of the secondary interconnect in order to increase the performance of the cell and, at the same time, to lower manufacturing costs. ü study of the current path in the cathodic and anodic collectors Genova, 12 Dicembre 2007

Geometry optimisation (2) Genova, 12 Dicembre 2007

Future work Ø Simulation of new geometries. Ø Optimisation study. Ø Complete model including ohmic, activation and concentration losses. Publications Ø Laura Repetto, Gerry Agnew, Adriana Del Borghi, Fabio Di Benedetto, Paola Costamagna. “Detailed Simulation of the Ohmic Resistance of SOFCs”: Journal of Fuel Cell Science and Technology; volume 4, issue 4, pp 413 -417. Ø S. Grosso, L. Repetto, P. Costamagna. “IP-SOFC model”, chapter 9 of the book “Modeling Solid Oxide Fuel Cells: Methods, Procedures and Techniques”, editor R. Bove, Springer, in press. Ø Laura Repetto, Paola Costamagna. “FEM Model of the Ohmic Resistance of IP-SOFCs”: Journal of Applied Electrochemistry; submitted. Genova, 12 Dicembre 2007

Thank you for your attention Genova, 12 Dicembre 2007