The current density and temperature distributions of anode-supported flat-tube solid oxide fuel cells affected by various channel designs

The advantages of a flat-tube solid oxide fuel cell (FT-SOFC) include easy sealing, low stack volume and low resistance to current collection. Because the performance of the FT-SOFC is closely linked to the interior hydrogen channel design, this paper studied various channel designs using a numerical approach. Ordinary FT-SOFCs have many channels with small cross-sectional areas. Unfortunately, this design makes it possible for the sealing material to block the channel entrance. Furthermore, it is difficult for the hydrogen to be evenly distributed under this type of design. To overcome these problems, a new design was developed to reduce the number of channels and increase the cross-sectional area. Contrary to expectations, the numerical approach applied here revealed that new design resulted in poor hydrogen transport into the support region and an average current density of 2846.7 A/m2, lower than that of the traditional design. Another design with a gradually increasing width from inlet to outlet was applied to increase the performance, maintain the mechanical strength and reduce the pressure drop of SOFCs. This design improved the average current density to 3135.4 A/m2. However, the cell performance with this channel design decreased significantly when the channel inlet became too narrow or when the outlet became too wide.

► The channel designs for flat-tube solid oxide fuel cells (FT-SOFCs) are studied in this paper. ► The FT-SOFC which has 13 channels with circle cross-sectional area takes 3291.5 A/m2. ► The FT-SOFCs having 3 channels with rectangular cross-sectional area are compared. ► The FT-SOFC having gradually increased width from the inlet to the outlet is 3135.4 A/m2. ► The FT-SOFC reversing inlet and outlet of the former design is 3283.14 A/m2.