Segmented cell in series design

Fig. 10.1 Pictures for the different designs of SOFCs and the related cross-sectional diagrams (a) electrolyte-supporting planar cell, (b) anode-supported planar cell, (c) tubular cell, (d) segmented cell in-series design.

The segmented cell in series design is being investigated by Mitsubishi Heavy Industries (Japan), ABB, and Rolls Royce. This cell contains segmented cells arranged in a thin, banded structure on a porous support alumina tube. The sealing is provided by the interconnect, which also serves as an electrical contact between the cathode of one cell and anode of the next cell (Fig. 4.18). The oxidant flows outside and the fuel flows from one cell to the next inside the tubular cell stack. 

Fig. 18.8 Impurities in anodes for four SOFC stacks with different materials and designs. Impurities were determined with SIMS on the 24 h operation and on the longer (about 5,000 h) operations, (a) High-temperature segment-in-series cell by MHI, (b) intermediate flatten tubular cell by Kyocera, (c) high temperature sealless tubular cells by TOTO, and (d) intermediate temperature disk-type planar cells by Mitsubishi Materials corp...

One effective method of cost reduction would be to reduce the operating temperature, and in this respect four types of stack have been developed. These include (i) a tubular design, with the tubes closed at one end (Westinghouse prototypes) or opened at both ends (ii) a planar technology (iii) a segmented series arrangement of individual cells (Rolls-Royce) and (iv) a monolith concept (Argonne National Laboratory). 

---