Temperature and stress distributions in micro-tubular SOFC

The runtime of mobile robotic platforms can be greatly increased using Solid Oxide Fuel Cell (SOFC) stacks fueled by readily available propane and hybridized with lithium ion batteries. However, SOFC systems suffer long-term degradation due to thermal cycling during startup and shutdown. The operating temperature range of the SOFC is around 800 to 1100 oC. The aim of this study is to understand the factors that influence the lifetime of micro-tubular Solid Oxide Fuel Cell (mSOFC) stacks. Three-dimensional models are developed to investigate the effect of operating conditions and temperature distribution on thermal stresses and electrical performance of mSOFC. The simulation results provide information about the location and magnitude of stresses for a given cell design. In addition, the sensitivity of axial and radial Von Mises stresses are analyzed using various temperature profiles. The model can be used determine the limit of thermal gradient induced stresses in the mSOFC components to avoid rapid degradation.