Transient Performance of Micro-Tubular Solid Oxide Fuel Cells and Stacks

Abstract

The transient performance of micro-tubular solid oxide fuel cells and six-cell stacks was investigated, with promising results. It was found that a single cell can take less than 0.5 seconds to adjust to load changes, even when the change crosses the majority of the cell's range. When steps of equal size were ranged across the current-voltage spectrum, more distortion was seen at the higher voltages. Six-cell stacks were tested with the cells arranged both in series and parallel. The response time was marginally longer for these stacks, being 0.6 to 0.7 seconds, irrespective of step size. Again, very good load-following characteristics were observed, with no observable degradation in performance. In addition, no under-shooting of the voltage was seen in any of these tests, despite several predictions of such in the literature.