Multiscale Electrochemistry Modeling of Solid Oxide Fuel Cells

Abstract

In this paper, we present two levels of electrochemical modeling for solid oxide fuel cells: cell continuum and microscale electrochemistry. The microscale electrochemistry model simulates the performance of porous electrode materials based on the microstructure of the material, the distribution of reaction surfaces, and the transport of oxygen ions through the material. The overall fuel cell current-voltage relations are obtained using the microscale electrochemistry modeling and form the basic input to the continuum level electrochemistry model. The continuum electrochemistry model calculates the current electrical density, cell voltage, and heat production in fuel cell stacks with H2 or other fuels, taking into account as inputs local values of the gas partial pressures and temperatures. This approach is based on a parameterized current-voltage (I-V) relation and includes the heat generation from both Joule heating and chemical reactions. It also accounts for species production and destruction via mass balance. The continuum electrochemistry model is then coupled with a flow-thermal-mechanical simulation framework for fuel cell stack design and optimizing operating conditions.