High-temperature fuel cell stack, and production thereof

Abstract

Disclosed is a cassette for a high-temperature fuel cell stack, comprising at least one fuel cell that encompasses an anode, a cathode, and an electrolyte, and a metal cell frame which surrounds the fuel cell. Said metal cell frame has two sections, i.e. an internal, thin compensating frame that contacts the fuel cell and a thicker, rigid external frame which is used for contacting the interconnector. The internal compensating frame comprises a circumferential bead at room temperature, said bead entirely disappearing at temperatures ranging between 980 DEG C and 1100 DEG C as a result of the prevailing stresses. The bead has special relief functions. It is significant that said special function of the formed bead is exclusively achieved by the fact that the faults in the compensating metal sheet or the compensating film are formed solely because of the joining sequence used, i.e. only in combination with the joining process used. In comparison, a part that already has a bead prior to the joining process could also compensate stresses but not to the same extent as a bead produced using said joining process.

Description

technical field [0001] The present invention relates to a high-temperature fuel cell system, especially a fuel cell system with an oxide ceramic electrolyte (SOFC=Solid Oxide Fuel Cell (Solid Oxide Fuel Cell)) and a manufacturing method thereof. Background technique [0002] A fuel cell is a source of electrical current in which chemical energy is converted into electrical energy by electrochemical oxidation of readily oxidizable substances, in most cases the oxidation of hydrogen with oxygen. Due to the low voltage supplied to the individual fuel cells, usually in order to increase the electrical performance, a number of fuel cells are connected in series via so-called interconnectors and are electrically insulated and sealed here with glass solder (Glaslot). (fuel cell stack). The individual cell layers (ie ceramic cells with metal interconnections) are also referred to as boxes. [0003] The operating temperature of a high temperature fuel cell stack (SOFC stack) is in ...

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Problems solved by technology

As a result, there is often a high risk of rupture for the ceramic cells due to fundamental differences in the thermal expansion of the cells and the interconnector as well as the frame, and especially due to the temperature differences that occur in SOFCs during heating and cooling.

[0008] In addition, there is a potential risk of cracking in the glass-solder joint between the individual boxes, since the glass-solder is in principle brittle and thermal stresses occur between the individual material layers as described above

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