Analysis of Thermal Stress Distribution Sensitivity in a Planar Solid Oxide Fuel Cell

A fuel cell is an electro-chemical tool capable of converting chemical energy into electrical energy. The high operating temperature of the solid oxide fuel cell (SOFC), (between 700oC to 1000oC), causes thermal stress which is the origin of crack initiation and propagation. Thermal stress causes gas escape, structure variability and SOFC operation cessation before its lifetime. The purpose of the current paper is to present a method that predicts the thermal stress distribution and forecasts the beginning of fissure or crack occurrences in an anisotropic porous electrode of the planar SOFC. The governing coupled non-linear differential equations of heat transfer, fluid flow, mass transfer, mass continuity, and momentum are solved numerically. A code based on computational fluid dynamics (CFD), computational structural mechanics and finite element method (FEM) is developed and utilized. The results show that the highest thermal stress occurs at the lower corners of anode and the upper corners of cathode. The cathode’s thickness at the left side increases by 1.5% and the concentrated temperature and thus the fissure occurs between the top and bottom left corners of the cathode.