Short Stack Kit for the Open Flange™ Set-up Using Soft Mica Seals

Abstract

Fiaxell has been active since 2008 in the Solid Oxide Fuel Cells (SOFC) industry and has been developing components and products for SOFC research. Fiaxell is the inventor of the “2R-Cell”, an anode supported cell able to withstand full re-oxidation and thermal cycles. The 2R-Cell is robust and has demonstrated high fuel utilization (85-90%) and electrical efficiency up to 50% with pure hydrogen on button cells. Fiaxell has developed the Open Flange™ Set-Up in order to test SOFC and SOEC cells. The Set-Up allows researchers to do various experiments, such as current-voltage characteristics, polarization, impedance spectroscopy measurements, electrolysis, co-electrolysis and in situgas processing (POX, SR) thanks to its integrated steam generator. Fiaxell is now offering a complete short stack kit that can be directly mounted onto the Open Flange™ Set-Up platform. This kit allows researchers to perform a range of experiments and to study stack parameters such as flow distribution, electrical contact resistance, and to investigate protective coatings to avoid chromium evaporation, in situfuel processing and sealing gas tightness. Each parameter can be independently characterized and optimized by combining ideal and real stack conditions on both sides of the cell, for instance Crofer steel on the anode and gold mesh on the cathode. Fiaxell is proposing Crofer 22H interconnects with different flow pattern designs for 50 X 50 mm and 80 X 60 mm cells. Alternatively, customers can propose their own customized design which can then be chemically grooved and laser cut by Fiaxell. The short stack kit comes with soft mica sealing but can also be made gas tight with any glass paste or other sealants. The soft mica seals have been designs to be easily removed and replaced, contrary to the use of glass based sealants that require mechanical grinding to remove. Mechanical simulations and calculations have been made to ensure that the design of the end Flange™ is adequate to compress the entire stack without any distortion or stress concentration points, especially on the interconnect plates. In order to see the gas distribution in the interconnect pattern, Fiaxell has developed an alternative, and complementary method to simulation, which consists of direct visualization and image analysis of the real flow motion. Screen captures will be included and discussed. In this paper, we present the experimental results of the short stack tests using two different interconnect patterns and also discuss the effectiveness of the soft mica gasket seals. Image caption: Exploded view of two cells short stack showing the three bipolar plates (interconnect) and soft mica gaskets (in beige). The short stack has been designed as a kit to be integrated directly on the Open Flange™ Set-Up platform. Figure 1