Glass coated compressible solid oxide fuel cell seals

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• 作者：M. Rautanen ; O. Thomann ; O. Himanen ; J. Tallgren ; J. Kiviaho
• 关键词：SOFC ; Seal ; Thermiculite 866 ; Glass ; Leak ; Stack
• 刊名：Journal of Power Sources
• 出版年：1 February, 2014
• 年：2014
• 卷：247
• 期：Complete
• 页码：243-248
• 全文大小：760 K

文摘

With the growing footprint of solid oxide fuel cell stacks, there is a need to extend the operating range of compressible gaskets towards lower stress levels. This article describes a method to manufacture SOFC seals by coating a compressible sealing material (Thermiculite 866) with glass to obtain good sealing performance even at compression stresses as low as 0.1聽MPa. Glass layer can be coated using an organic carrier consisting of terpineol, ethanol and ethyl cellulose. The coated seals can be heat treated by simply ramping the temperature up to operating temperature at 60聽Kh^鈭? and therefore no extra steps, which are typical to glass seals, are required. Coated seals were manufactured using this route and evaluated both ex-situ and in a real stack. Leak rates of 0.1-0.3聽ml聽(m聽min)^鈭? were measured at 2-25聽mbar overpressure using 50/50 H₂/N₂. A 30-cell stack was manufactured and tested using coated seals. At nominal operating conditions of 0.25聽A聽cm^鈭? and 650聽掳C average cathode temperature, 46% fuel utilization and 20% air utilization the stack had a total hydrogen cross leak of 60聽ml聽min^鈭? corresponding to 0.7% of the inlet hydrogen flow rate.