Simulazione dettagliata della resistenza ohmica per celle IP-SOFC

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

2. 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 • Development of a physical / matematical model • Model validation • Use of the model to predict the IP-SOFC performance

3. Tubular geometry Planar geometry Solid Oxide Fuel Cell (SOFC) 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

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

5. Model equations

6. 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)

7. Comsol results (1) Norma della densità di corrente nell’elettrolita Femlab Matlab

8. e- e- Comsol results (2) Colour map of the Voltage

9. e- e- Comsol results (3) Streamlines and colour map of the current density norm

10. 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: • study of the current path in the electrolyte • study of the current path in the cathodic and anodic collectors 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.

11. Geometry optimisation (2)

12. Future work • Simulation of new geometries. • Optimisation study. • Complete model including ohmic, activation and concentration losses. • Publications • 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. • 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. • Laura Repetto, Paola Costamagna. “FEM Model of the Ohmic Resistance of IP-SOFCs”: Journal of Applied Electrochemistry; submitted.

13. Thank you for your attention