Interconnection for Electrically Connecting the Cells

The interconnection requires two interconnect wires but these are often combined into a single material which makes contact with the anode on one side and the cathode on the other. 

Fl0iire 1.7 Expansion of Lao. TsSr. oCrOs as the oxygen is extracted by hydrogen [25]. 

To avoid these problems, Sulzer has used metal interconnects in their small-scale residential SOFC heat and power unit [29]. The alloy is largely chromium, with 5 wt% iron and 1 wt% yttria to give dispersion strengthening, made by Plansee AG in Austria. This alloy has almost the same expansion coefficient as YSZ and has the benefit of improved strength and toughness when compared with lanthanum chromite. But it requires coating to prevent chromium migration and is also expensive at the present time. 

Another approach is to adopt a design similar to the lead acid battery and to use wires brought out from the electrodes and connected externally. This is the approach adopted by Adelan in their microtubular design. Clearly, the design of the cells and how they fit into the overall stack is vitally important in deciding such issues. 

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