The efficiency and lifetime of solid oxide fuel cells (SOFCs) is compromised by mechanical failure of cells in the system. Improving the mechanical reliability is a major step in ensuring feasibility of the technology. To quantify the stress in a cell, mechanical properties of the different layers need to be accurately known. Since the mechanical properties are heavily dependent on the microstructures of the materials, it is highly advantageous to understand the impact of microstructures and to be able to determine accurate effective mechanical properties for cell or stack scale analyses. The purpose of this work is to provide such a link. State-of-the-art SOFCs are supported by a porous layer of Ni-3YSZ which has a complex microstructure and a drastic difference in behaviors between their phases. This work investigates the microscopic stress distribution and macroscopic creep rate of porous Ni-3YSZ in the operating temperature through numerical micromechanical modeling. Three-dimensional microstructures of Ni-3YSZ anode supports are reconstructed from a two-dimensional image stack obtained via focused ion beam tomography. Time-dependent stress distributions in the microscopic scale are computed by the finite element method. The macroscopic creep response of the porous anode support is determined based on homogenization theory. It is shown that micromechanical modeling provides an effective tool to study the effect of microstructures on the macroscopic properties.
|Title of host publication||Proceedings of 11th European SOFC and SOE Forum 2014|
|Number of pages||10|
|Publisher||European Fuel Cell Forum|
|Publication status||Published - 2014|
|Event||European fuel cell 2014 - 11th European SOFC and SOE Forum 2014 - Lucerne, Switzerland|
Duration: 1 Jul 2014 → 4 Jul 2014
|Conference||European fuel cell 2014 - 11th European SOFC and SOE Forum 2014|
|Period||01/07/2014 → 04/07/2014|
Kwok, K., Jørgensen, P. S., & Frandsen, H. L. (2014). Micromechanical Modeling of Solid Oxide Fuel Cell Anode Supports based on Three-dimensional Reconstructions. In Proceedings of 11th European SOFC and SOE Forum 2014 [B1109] European Fuel Cell Forum.