CN100524894C - Flat-plate -type solid-oxide fuel battery stack sealing method and its dedicated sealing member - Google Patents

Abstract

A flat-plate solid oxide fuel cell stack sealing method is characterized in that sealing glass is used as the sealing base material, NiO powder is used as an anode coating, LSM cathode powder is used as a cathode coating raw material, and NiO powder and LSM cathode powder are made into a spray solution , and then sprayed on the sides of the sealing glass as required, and the dried sealing material is used for the sealing of single cells and stainless steel connectors or single cells and other components in the battery stack. The invention also discloses a corresponding special seal. It can greatly improve the chemical stability of the sealing material and reduce its thermal expansion coefficient to the same level as the sealed component, thereby greatly reducing the thermal stress during the thermal cycle of the solid oxide fuel cell stack, promoting sealing and improving fuel efficiency. Battery Life.

Description

Flat-type solid oxide fuel cell stack sealing method and its special seal

technical field

The invention relates to a fuel cell stack sealing method and the technical field of related sealing elements.

Background technique

In a flat solid oxide fuel cell stack, the sealing of single cells and connectors, single cells and other components is particularly critical to prevent the leakage of fuel and oxidizing gas, resulting in mixed explosions. During high-temperature operation of high-temperature solid oxide fuel cells, the sealing between single cells and metal connectors and other components requires similar thermal expansion coefficients and chemical compatibility. Therefore, it is important to invent a composite sealing method with stable performance and a thermal expansion coefficient close to that of a single cell.

Existing published patents, such as the sealing method described in CN 1825672A, CN 1649186A, CN 1494176A, CN 1599092A, etc., have the mixture of glass-ceramic, glass matrix and ceramic fiber as the sealing material. However, due to the different thermal expansion coefficients and unstable chemical stability of the existing sealing material technology during the thermal cycle of the solid oxide fuel cell, there will be gaps between the sealing material and the sealing parts during the operation of the fuel cell, and the surface of the sealing material will be damaged. Problems such as peeling or cracking of the battery. So further improvement and design are needed.

The present invention is used for sealing between single cells and stainless steel connectors or other components in solid oxide fuel cell stacks, and it is aimed at between single cells of solid oxide fuel cells and stainless steel connectors, single cells and other components A new way of sealing. The applicant used sealing glass+spray+YSZ or LSM cathode powder+solid oxide fuel cell (Sealing glass+Spray+NiO or LSM powder+Solid oxide fuel cell) as a key word to retrieve the U.S. "Metals Abstracts" (Metals Abstracts) ), "Engineering Abstracts Index" (EI) in the United States, my country's "China Journal Network" and "VIP Chinese Periodical Database" and other scientific and technological literature indexes have not found complete relevant literature. The applicant also searched the United States Patent Abstracts and European Patent Abstracts (EP&PCT) and "China Patent Information Network" and found no similar patents.

Contents of the invention

The primary technical problem to be solved by the present invention is to provide a flat-plate solid oxide fuel cell stack sealing method, which can greatly improve the chemical stability of the sealing material, and reduce its thermal expansion coefficient to the same extent as the sealed component, so that it can Greatly reduces thermal stress during SOFC stack thermal cycling, facilitates sealing and increases fuel cell life.

Another technical problem to be solved by the present invention is to provide a special sealing member in the above method, so as to promote sealing and improve the service life of the fuel cell.

The technical scheme adopted by the present invention to solve the above-mentioned primary technical problems is: a flat-plate solid oxide fuel cell stack sealing method, which is characterized in that sealing glass is used as the sealing base material, NiO powder is used as the anode coating, and LSM cathode powder is used as the cathode Coating materials, NiO powder and LSM cathode powder are made into spray solution, and then sprayed on the side of the sealing glass as required. The dried sealing material is used for the sealing of single cells and stainless steel connectors or single cells and other components in the battery stack.

Preferably, the coating thickness of the sealing glass is in the range of 5-15 μm, and the thickness of the glass is in the range of 0.1-0.3 mm, which is convenient for use in sealing the actual flat-plate solid oxide fuel cell stack.

The spraying solution uses 40-60wt.% ethanol and 60-40wt.% polyethylene glycol as solvents, the particle size of the powder is in the range of 4.5-10 μm, and the concentration of the spraying solution is in the range of 20-30wt%, which is convenient for spraying.

The technical solution adopted by the present invention to solve the above-mentioned another technical problem is: a special sealing member in the sealing method of a flat-plate solid oxide fuel cell stack, which uses sealing glass as the sealing base material, and the sides of the sealing glass are respectively coated with NiO powder Anodic coating of LSM cathode powder or cathodic coating of LSM cathode powder.

The coating thickness of the sealing glass is in the range of 5-15 μm, and the thickness of the glass is in the range of 0.1-0.3 mm.

The particle size of the powder is in the range of 4.5-10 μm.

Compared with the prior art, the present invention has the advantages that: by adopting the above-mentioned sealing method, the chemical stability of the sealing material can be greatly improved, and its coefficient of thermal expansion can be reduced to the same degree as that of the sealed component, while the improvement of thermal stability and thermal expansion The reduction of the coefficient can greatly reduce the thermal stress during the thermal cycle of the solid oxide fuel cell stack, promote sealing and improve the life of the fuel cell. Therefore, the sealing glass that has been sprayed with NiO, LSM and other powders as the raw material for the composite The sealing material can seal between single cells and stainless steel connectors and other components in a solid oxide fuel cell stack, and achieves remarkable practical effects.

Description of drawings

Figure 1 is a partially cut perspective view of a solid oxide fuel cell stack, and the drawing numbers are 1, 3, 5, 7—sealing glass, 4—sealing separator, 2—single cell, 6—stainless steel connector, two sealing glasses A sealing partition is clamped to form a sealing assembly, such as 3, 4, and 5 to form a sealing assembly.

Fig. 2 is a schematic diagram of sealing between a single cell and a stainless steel connector in a solid oxide fuel cell stack; the figure number is 8-430 stainless steel connector; 9-coating; 10-sealing glass; 11-single cell.

Fig. 3 is a partially enlarged schematic diagram of the composite sealing material, and the drawing numbers are 12—LSM coating; 13—sealing glass; 14—NiO coating.

Detailed ways

The present invention will be described in further detail below in conjunction with the embodiments and accompanying drawings.

As shown in Figures 1-2, the sealing between the single cells 11 and the 430 stainless steel connectors 8 in the battery stack. During the assembly process of the battery stack, there is a connection between the single cells 11 and the single cells 11 to separate hydrogen and oxygen, and the plate is a 430 stainless steel connection 8 . One side of the connector 8 is in contact with the cathode of the single cell 11, and the other side is in contact with the anode of the single cell 11, that is, oxygen gas is passed through while hydrogen gas is passed through. The connecting piece 8 is sprayed with LSM cathode powder on the oxygen-passing layer, and nickel-plated on the hydrogen-passing side. In order to prevent hydrogen from leaking, it will explode when mixed with oxygen. A sealing material component needs to be added on the two sides of the periphery of the connecting member that are in contact with the cells, where the sealing material is usually sealing glass 10 . Because the thermal expansion coefficient of the sealing glass is different from that of the single cell and its chemical stability is not good enough, a layer of LSM powder coating 9 of about 10 μm is sprayed on the side of the sealing glass 10 that is in contact with the cathode of the single cell 11, which is the same as spraying LSM stainless steel. The layer in contact with the connector is also sprayed with a layer of LSM powder coating 9 of about 10 μm to make a special seal, which is sealed between the single cell cathode and the stainless steel connector. A layer of sealing glass 10 is also added between the anode of the single cell and the nickel-plated stainless steel connecting piece. Both sides of the sealing glass 10 are coated with a layer of NiO powder coating 9 of about 10 μm to make a special seal. Sealed between the cell anode and the nickel-plated stainless steel connection. During the operation of the battery stack, the NiO coating on the first layer of the sealing glass is reduced to Ni coating by hydrogen, and its chemical stability and thermal expansion coefficient are exactly the same as those of the nickel-plated stainless steel connectors, thereby minimizing the thermal cycling process. The resulting thermal stress and maximized its chemical stability.

Of course, in some sealing occasions, sealing glass 13 with a thickness of 0.1-0.3 mm can be used as the sealing base material, NiO powder with a particle size of 4.5 μm, and LSM cathode powder are respectively made into spray solutions, and the solvents are 50wt.% ethanol and 50wt. % polyethylene glycol, and control the mass concentration in the range of 20 to 30%, so that NiO coating 14 is sprayed on both sides of the sealing glass 13 as an anode coating, and LSM coating 12 is a cathode coating, and it is made after drying For special seals, as shown in Figure 3, the thickness of each coating is about 15 μm. The dried sealing material can be used for the sealing of single cells and stainless steel connectors or single cells and other components in the battery stack.

Claims (7)

1, a kind of flat-plate-type solid-oxide fuel battery stack sealing method, it is characterized in that adopting seal glass as the sealing basic material, the NiO powder is that anodic coating, LSM cathode powder are the cathode raw material, NiO powder, LSM cathode powder are made spray solution, be sprayed at the side up and down of seal glass subsequently as required, dried encapsulant is used for the sealing of battery pile monocell and stainless steel adapting piece or monocell and other assemblies.

2, method according to claim 1, the coating layer thickness that it is characterized in that described seal glass is at 5～15 mu m ranges, and thickness of glass is in 0.1～0.3mm scope.

3, method according to claim 2, it is characterized in that described spray solution is to adopt 40～60% (wt) ethanol and 60～40% (wt) polyethylene glycol as solvent, the powder particle size is at 4.5～10 mu m ranges, and the concentration of spray solution is 20～30% (wt) scope.

4, method according to claim 3 is characterized in that described spray solution is to adopt 50% (wt) ethanol and 50% (wt) polyethylene glycol as solvent.

5, special-purpose seal in a kind of flat-plate-type solid-oxide fuel battery stack sealing method, it is characterized in that adopting seal glass as the sealing basic material, the side up and down of seal glass scribbles the anodic coating of NiO powder or the cathode of LSM cathode powder respectively.

6, seal according to claim 5, the coating layer thickness that it is characterized in that described seal glass is at 5～15 mu m ranges, and thickness of glass is in 0.1～0.3mm scope.

7, seal according to claim 6 is characterized in that described powder particle size is at 4.5～10 mu m ranges.

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