JPH01186760A - Fuel cell - Google Patents

Abstract

PURPOSE:To prevent the generation of a large gas leakage even when a crack is generated at an electrolyte plate, and to improve the safety, by composing the cell with thick sheet of an electrolyte plate arranged at the cathode side, a thin sheet of the catalyst plate arranged at the cathode side, and a metallic powder sintered plate arranged between the both sheets. CONSTITUTION:An electrolyte plate 1 is divided into a thick sheet 9 and a thin sheet 10, and a metallic powder sintered plate 11 is furnished between the both sheets 9 and 10 to compose a fuel cell. The thin sheet 10 is contacted to an anode 2 while the thick sheet 9 is contacted to a cathode 3, and, the sheets 9 and 10 and the metallic powder sintered plate 11 are all made in the same form larger than the anode 2 and the cathode 3. When the thick sheet 9 of the electrolyte plate 1 is cracked, the metallic powder sintered plate 11 prevents the cross leakage of the fuel, and the strength of the metallic powder sintered plate 11 is maintained by the sheets 9 and 10 holding the plate 11. In such a composition, the cross leakage of the fuel is prevented and the safety of the fuel cell can be secured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to molten carbonate fuel cells.

[Prior Art] Fig. 2 shows an example of a conventional molten carbonate fuel cell, in which an anode 2 smaller than the electrolyte plate 1 is arranged on one side of the electrolyte plate 1, and a cathode 3 is arranged on the other side. Furthermore, a reduction side metal member 5 is provided which has a recess surrounding the anode 2 other than the side surface of the electrolyte plate 1, and has a fuel passage 4 for guiding fuel to the anode 2 at the bottom of the recess. An oxidizing side metal member 7 is provided at the bottom of the recess, which has an oxidizing agent passage 6 for guiding the oxidizing agent to the cathode 3. By sandwiching the electrolyte plate l at the protruding parts of
A reduction side and an oxidation side are separated.

8 in the figure is a BPB (bubble pressure barrier) installed between the electrolyte plate 1 and the anode 2 and having the same size as the anode 2, and mainly uses a sintered plate of metal powder. There is.

The molten carbonate fuel cell is normally operated at a temperature of about 650°C. .7, the electrolyte plate I often cracks. When this crack occurs, fuel leaks to the oxidizing agent side, creating a danger of combustion, explosion, etc.

For this reason, in the past, BP was used between the electrolyte plate 1 and the anode 2.
B8 is provided to reduce cross leakage of fuel gas when cracks occur in the electrolyte plate.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional device, when the electrolyte plate 1 generates a crack C at the end position of the anode 2 and BPB 8, the gap between the metal member 5 and the anode 2 and BPB 8 There is a risk that a large amount of fuel gas may cross-leak L from the gaps between the two.

The present invention was made by focusing on the above-mentioned conventional problems.
The purpose is to improve the safety of fuel cells by preventing large gas leaks from occurring immediately even if an electrolyte plate cracks anywhere.

[Means for Solving the Problems] The present invention attempts to solve the above technical problems, and
In a molten carbonate fuel cell, between an anode housed in a metal member on the reduction side and a cathode housed in a metal member on the oxidation side, the anode has a larger shape than the anode and the cathode, and is disposed on the cathode side. Relating to a fuel cell characterized by having an electrolyte plate consisting of a thick sheet, a thin sheet placed on the anode side, and a metal powder sintered plate of the same size as both sheets placed between the two sheets. It is something.

[Operation] Accordingly, in the present invention, the metal powder sintered plate prevents cross-leakage of fuel when the thick sheet of electrolyte plate cracks. Further, the strength of the metal powder sintered plate is maintained by being held between the sheets, and oxidation of the metal powder sintered plate is prevented by locating the neutral point of reduction and oxidation inside the thick sheet.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the present invention, in which the electrolyte plate 1 is divided into a thick sheet 9 and a thin sheet 10, and both sheets 9 are further divided into a thick sheet 9 and a thin sheet 10.
．． A metal powder sintered plate 11 is arranged between the thin sheets 10 and 10, and the thin sheet 10 is used as the anode 2, and the thick sheet 9 is used as the anode 2.
are brought into contact with the cathode 3, respectively, and the sheet 9. Each of the IO and metal powder sintered plates 11 is formed into the same shape larger than the anode 2 and cathode 3, and the ends of the two sheets 9.10 are sandwiched between the outer peripheral protrusions of the metal member 5.7. ing.

Further, the thick sheet 9 is formed to have such a thickness that the neutral point n between the reducing atmosphere and the oxidizing atmosphere is located inside it.

With the above configuration, the metal powder sintered plate 11 and the reduction side metal member 5
A thin sheet 10 is provided between the metal powder sintered plate 11 and the oxidized metal member 7, and a thick sheet 9 is provided between the metal powder sintered plate 11 and the oxidized metal member 7.

Further, the metal powder sintered plate 11 has a problem in that its strength decreases as oxidation progresses. For this reason, the thickness of the sheet 9 is increased so that the neutral point n is located inside the thickness of the thick sheet 9, so the metal powder sintered plate 11 is always placed in a reducing atmosphere to maintain its strength. can be done.

Even if the thick sheet 9 cracks in this state, since the metal powder sintered plate 11 covers the entire surface of the thick sheet 9, the strength of the metal powder sintered plate 11 will prevent the crack from penetrating the electrolyte plate 1. do not have.

Moreover, as time passes, the metal powder sintered plate 11 is gradually oxidized from the cracked part of the thick sheet 9, and its strength decreases.
It is supported by the metal members 5 and 7 via the metal members 5 and 7, and there is almost no possibility of cracking.

Therefore, even if cracks occur in the thick sheet 9 at any location, fuel cross leakage can be prevented and the safety of the fuel cell can be ensured.

It should be noted that the present invention is not limited to the above-described embodiments, and the illustrated structure may be repeatedly laminated in multiple layers, and the thick sheet may have a single structure or a structure formed by stacking a plurality of thin sheets. It goes without saying that various changes can be made without departing from the gist of the invention.

[Effects of the Invention] As described above, according to the fuel cell of the present invention, a thick sheet with an electrolyte plate disposed on the cathode side, a thin sheet disposed on the anode side, and a sintered metal powder disposed between the two sheets. Since it is composed of a plate, even if a crack occurs in the thick sheet, the metal sintered plate prevents fuel from cross-leaking to the oxidizing atmosphere side, and furthermore, both sides of the metal powder sintered plate are supported by the sheet. This makes it possible to effectively maintain its strength, and by selecting the thickness so that the neutral point is located inside the thick sheet, the metal powder sintered plate can be maintained in a reducing atmosphere. This can provide excellent effects such as preventing the oxidation of oxidation.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of a conventional fuel cell. ■ is an electrolyte plate, 2 is an anode, 3 is a cathode, 5 is a metal member on the reduction side, 7 is a metal member on the oxidation side, 9 is a thick sheet, 1
0 indicates a thin sheet, and 11 indicates a metal powder sintered plate.

Claims (1)

[Claims] 1) In a molten carbonate fuel cell, there is a space between an anode housed in a metal member on the reduction side and a cathode housed in a metal member on the oxidation side. A fuel cell characterized by having an electrolyte plate consisting of a thick sheet placed on the anode side, a thin sheet placed on the anode side, and a metal powder sintered plate having the same size as both sheets placed between the two sheets. .