Multiscale approach to simulate multiphysics in Solid Oxide Cell (SOC) electrodes

  • Rodríguez Cambra, Álvaro (ITAINNOVA)
  • García Camprubí, María (ITAINNOVA)
  • Gil, Francisco (ITAINNOVA)
  • Sáenz, Carlos (ITAINNOVA)
  • Ortún, Javier (ITAINNOVA)

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Solid Oxide Cells (SOCs) are electrochemical devices that convert the chemical energy of a fuel directly into electrical energy when operating in fuel mode, or vice versa when in electrolysis mode. They commonly consist of a porous anode of a Ni-YSZ cermet, a porous cathode of LSM and a dense electrolyte of YSZ. This technology is in a pre-commercial stage that has to face challenges such as degradation phenomena or scalability to reach the market. Simulation tools can pave the way to commercialization by providing useful insight into the coupled multiphysics phenomena occurring in the porous electrodes, namely: mass transport, charge transfer, conjugate heat transfer, electrochemical/side reactions, etc. In this work, a multiscale approach to simulate multiphysics in Solid Oxide Cell (SOC) electrodes is presented. First step of the methodology addresses the reconstruction of the porous structure of the electrodes. To this end, LIGGGHTS®, an open-source Discrete Element Method (DEM) code, is coupled with SPPARKS, an open-source Kinetic Monte Carlo (KMC) code. The resulting geometry stands for the domain of study for the detailed analysis of the multiphysics in the electrode. This is addressed using an in-house model implemented in OpenFOAM®, an open-source code based on the Finite Volume Method (FVM). The results are then used to determine macroscopic parameters required by the classical porous media approach of the FVM, such as permeability and the effective volumetric active area. These outcomes can then be used to enhance the accuracy of the macroscale simulation of a full SOC. The methodology and its application to a specific SOC anode is presented. The anode microstructure is generated and the reaction areas are identified. Then the anode operation is simulated to assess macroscopic parameters of the porous media. The results are compared with the standard macroscopic approaches used in the literature.