Development of Segmented-in-series Cell-stacks with Flat-Tubular Substrates

The SOFC cell-stacks called "flat-tube segmented-in-series cell-stacks" have been developed jointly by Tokyo Gas and Kyocera. The cell-stacks were composed of multiple single-cells (8YSZ electrolyte, Ni/8YSZ anode, and LaSrCoFe cathode) and current-collectors, placed on both sides of the flat-tubular substrate. The fuel to electric power-generation efficiency of the latest cell-stack converted as the methane fuel was estimated to be more than 53% HHV-DC at 1023 K at the current density, 0.2 A/cm(2). The complex impedance spectra of the cell-stacks were measured under the operating conditions, for investigations of the relation between the performance and components design. By the measurements under several conditions, we identified the relationship between the impedance spectra and the fuel usage dependence and degradation of the segmented-in-series type cell-stack performance. Based on these results, we are continuing further studies of the component design (especially anode), for higher efficiency and long-term durability of the cell-stacks.