Medium and high temperature sealing method of plate type solid oxide fuel battery and its sealing material

Abstract

A series of sealant materials suitable to 800-1000 deg.C are prepared by using microcrystalline glass in system of CaO-Al2O3-SiO2-B2O3. Range of softening temperature of the series of microcrystalline glass is 750-850 deg.C, and range of crystallizatino is 800-1000 deg.C. In warming up procedure, pristine glass softened at 750-850 deg.C is drenched and adhered with ZrO2 electrolyte and Ni-Cr material of bipolar plate. When temperature goes up continuously, integral recrystallization is occurred, and intensity of material is enhanced. Experiments prove that the material suits to sealing use at temperature 800-1000 deg.C: certain mechanical strength and size, wettability, coefficient of thermal expansion, chemical stability and good matching to materials of batteries. The invention possesses advantages of wide range of sealing temperature, easy manufacturing and sealing technique and high cost performance ratio.

Description

Technical field [0001] The invention relates to a medium-high temperature sealing method for a flat solid oxide fuel cell. Background technique [0002] Solid oxide fuel cell (SOFC) is highly efficient (not limited by Carnot cycle, thermoelectric efficiency can reach 70%-80%), environmentally friendly (no combustion process, almost no nitrogen and sulfur oxides), quiet ( No moving parts, low noise) and high reliability, it is called the green energy of the 21st century. Compared with other structures such as tubular, series-sealed and corrugated, the planar SOFC structure has the advantages of short current flow, uniform collection, and high battery power density. It has always been the main object of SOFC research and development. [0003] Due to the medium and high temperature, fuel gas (H 2 etc.) and oxidizing gases (O 2 etc.), if the parts of SOFC or the connection between different parts leak, and the two gases mix, the SOFC will not work, and in severe cases, it wil...

AI Technical Summary

Problems solved by technology

However, the preparation process of sealant and its sealing technology are relatively complicated, especially the strict cleaning requirements of the sealing place restrict its application occasions

Because in order to further increase the power density of the current planar SOFC, the development trend is to thin the working layer (to reduce internal resistance), and the working layer of 30-50 μm is easily damaged during repeated cleaning with strong acid and strong alkali solutions.

At the same time, it is difficult to ensure that the paste sealant is applied evenly during the sealing process, and the lack of certain high-temperature dimensional stability will bring difficulties to the cooperation between the bipolar plate and the battery body

Moreover, the paste glue will shrink greatly when kept at high temperature for a long time, which will cause deformation and stress concentration, and eventually lead to sealing failure

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