Tubular Cell Design Seal-Less

Tubular design of SOFC was initially made by Siemens Westinghouse, USA. Each tube in the mbular stack is made of a large test tube closed at one end which eliminates seal requirement. The tubular SOFC consists of two tubes, i.e. an outer tube and an iimer tube (Fig. 4.13a). The outer mbe (cell tube) consists of an inner surface and outer surface. The outer surface of the ceU tube is regarded as the anode side of the ceU and the iimer surface is considered to be the cathode side of the cell tube. The solid electrolyte is fabricated within the inner and outer surface of the cell tube. The inner tube is also known as the injection/guidance mbe. The injection tube is made up of alumina through which preheated air is injected towards the bottom of the ceU mbe. This preheated air then Uows over the cathode surface of the cell through the gap between the cell and injection mbes. 

For the bell and spigot design, electrolytes are developed in the form of short cylindrical segments in order to fit them onto each other and be connected to form a long tube by the bell and spigot joints as shown in Fig. 4.16. 

Another SOFC design known as the SOFC roll design has been fabricated using tape-casting and co-firing as a single unit (Fig. 4.17). The roll geometry eliminates 

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. 

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