Sealing arrangement for high-temperature fuel cell stack

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This patent presents a novel sealing assembly specifically designed for high-temperature fuel cell stacks, such as those used in solid oxide fuel cells (SOFCs). The invention features a ceramic insulation layer with a specially formulated brazing material (solder) that includes germanium and optionally silicon and aluminum titanate. This composition greatly improves the gas-tightness, electrical insulation, and mechanical strength of connections between metal components, reducing issues such as solder leakage, porosity, and electrical shorting, while ensuring reproducible, reliable seals under high operating temperatures.

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• Sealing and electrically insulating joints between metal parts in high-temperature fuel cell stacks (e.g., SOFCs).
• Forming gas-tight, electrically insulated connections in other high-temperature electrochemical devices or reactors.
• Manufacturing robust stack assemblies for industrial-scale energy systems that require durable, long-lived seals between ceramics and metals.
• Use in processes where reliable high-temperature insulation and gas tightness are essential, such as in advanced batteries or chemical reactors.

BenefitsContent extracted from patent full text and abstract with AI.

• Improves gas-tightness of metal-ceramic seals, minimizing leaks even at high temperatures.
• Reduces porosity and the risk of solder running or leakage, thus enhancing mechanical durability and reliability.
• Ensures strong electrical insulation between metallic stack components, preventing short-circuits.
• Compatible with common manufacturing techniques such as thermal spraying, thus facilitating cost-effective production.
• Offers reproducible results and high consistency in seal performance, supporting mass production.
• Enables longer device lifetime and better efficiency in fuel cell stacks, contributing to reduced operational costs.

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Patent Abstract

Disclosed is a sealing assembly for metal components, wherein the sealing assembly has an electrical insulating effect, and wherein the sealing assembly comprises a ceramic layer and a base brazing material disposed thereon, to which germanium is added. The addition of germanium advantageously ranges from 0.1 to 5.0 mol %, and preferably between 0.5 and 2.5 mol %. A particular embodiment provides for the use of a brazing material which additionally comprises silicon in the range of >0 to 2.5 mol %, and preferably between 0.1 and 0.9 mol %. Furthermore, a brazing material having a further addition of 10 to 40% by volume of Al2TiO5, and preferably between 20 and 30% by volume of Al2TiO5, has proven to be particularly suited for the sealing assembly. The use of the special brazing material composition inside the sealing assembly generally results in reproducibly tight and insulating joints having the following properties: a) escape of brazing material is prevented and running of brazing material is reduced, b) the porosity of the brazing material (primarily individual pores or narrow pore lines) is markedly reduced, c) the brazed joints have sufficient electrical resistance, and d) the brazed joints are generally sufficiently gas-tight (leakage rate during He leakage test