Dynamic analysis of current overshoots in reversible solid oxide cells

Abstract

Reversible solid oxide cell (RSOC) has attracted significant attention due to its multi-functionalities for energy conversion and storage. This device works as a fuel cell (FC) or an electrolyzer cell (EC) with superior efficiency. However, its dynamic response is complex and may cause a large overshoot of current operated in reversible cell mode, which impairs the long-term stability of RSOC. Although several works report the overshoot phenomenon, the mechanism and effects on cell performance are still unclear so far. In this work, we build a 3D dynamic planar RSOC model to investigate the detailed behavior of overshoot. The results show that the overshoot of current for RSOC can be caused under switching mode conditions. Especially a larger overshoot of current can be observed within switching mode from EC to FC. The overshoot of current is mainly caused by the load change, slower gas diffusion, and differentiated temperature distribution in RSOC.