Transient thermomechanical analysis of a 1 kW solid oxide fuel cell stack based on 3D multiphysical field model

Abstract

ABSTRACT In this paper, a model of a complete structured methane (CH4) internal reforming solid oxide fuel cell (SOFC) stack is developed. Material properties are extracted from experiments to establish a numerical simulation model to elucidate the mechanical failure mechanism of the stack under the combined effect of multiple factors. The steady-state and transient temperature and stress distributions of the stack are investigated. Results show that the higher the number of stacked layers, the more inhomogeneous the temperature distribution, the lower the fuel and oxygen (O2) utilization and potential of the cell, and the reduced flow rate in the top layer. The maximum temperature difference decreases rapidly during the first 50 mins of the stack shutdown. The first principal stress at the anode of the co-flow stack first decreases in the first few minutes of shutdown, then increases rapidly and is higher than the value at time 0. The first principal stress in the anode of the counterflow stack first increases and then decreases, with an increase of about 100 MPa. The maximum first principal stresses of the electrolyte and cathode decrease nearly monotonically, and the first principal stresses are smaller than the steady-state values.