Parallel Connection of Single Solid Oxide Fuel Cells to Increase Availability

摘要

With a simple cell model a comparison between different connection concepts of single solid oxide fuel cells (SOFC) has been accomplished. The simulation shows that in the case of unequal single cell resistances of a given stack the power generated by a parallel connection is larger than that by a serial one. Additionally it is easier to avoid cell overload in a parallel connection. In contrast the parallel connection of cells suffers from a small output voltage at high currents that has to be converted to higher voltages. A mixed concept of parallel and serial connection is proposed. Also an electronic converter has been developed for an SOFC with an output power of 200 W at 12 V output with an input voltage of only 2.8 V, that is only four SOFC single cells or parallel branches connected in series respectively. The efficiency of the converter is 94 % at the specified operation point.