Numerical modeling and current collection designs for flat-chip solid oxide fuel cell

A newly developed flat-chip solid oxide fuel cell (FCSOFC) shows advantages for its improved tolerance towards fast start-up and thermal shock, which makes it suitable to serve as portable or backup power supplier. In this study, a three-dimensional electro-chemo-thermo coupled numerical model is developed to analyze the factors limiting the power output of FCSOFC. Experiments are also carried out to acquire the effective electrode properties and validate model accuracy. The simulation results indicate that a feasible modification strategy is to reduce the ohmic loss in the anode nonreactive region. Three potential designs of the current collection are therefore proposed, with varied current collection passages placed at the vertical side, upper surface, and internal of the anode, respectively. Since collecting current from vertical side has limited current-conduction cross section and placing current collector on anode-sitting surface reduces cell functional electrode area, the third design, i.e. enhancing current collection from internal anode is recommended. The effects of current collector size on cell performance are investigated based on simulation. A maximal average current density of 776.76 A m−2 is obtained, increased by 17.4% compared with the original structure. The analysis also shows that for upper and internal collector designs, the cell performance has a nonmonotonic relationship with the collector size. The optimal anode current size is determined by the joint effects of various polarizations. The study shows that the proposed numerical model is effective to improve cell performance, providing insightful guidance for the design of FCSOFC.