A novel interconnect design of solid oxide fuel cell stacks to mitigate thermal and electrochemical imbalance

Kurzfassung

With the growing demand for eco-friendly energy to against the climate change, solid oxide fuel cell (SOFC) is gaining attraction. However, SOFC suffers from performance degradation during long-term operation due to various stresses that occur within the stack, which is a barrier to commercialization. Since the inhomogeneous operating environment generated during the practical operation is the main source of various stresses, we have proposed a new stack design (J. Kim, et al., 2021) to uniformize the inhomogeneous operating environment formed in the conventional crossflow type stack design (reference design). However, the computational model used in that previous study assumed electrochemical reactions as constants and did not consider charge conservation, which limits the prediction accuracy of the simulations. In addition, it mainly focuses on the heat transfer mechanism in the vertical direction of the entire stack and does not analyze various physical phenomena within a single repeating unit. In addition, there was a lack of explanation of how and why the new design was derived. The limitations and shortcomings of our previous work are addressed in this study. A detailed comparison of the reference and the new design in terms of temperature, chemical species and electrochemical reactions are performed based on three-dimensional multiphysics simulation. The electrochemical reaction kinetics are calculated by Butler-Volmer equation, and the charge conservations are computed to improve the reliability of the simulation results. Also, the detailed heat and mass transfer phenomena inside one repeating unit of the stack were analyzed. Furthermore, it was explained in detail how basic thermal and flow management principles were applied in the process of deriving the new design. The simulation results demonstrated that the new design operates in a more homogeneous environment compared to the reference design.