JPH06231777A - Solid electrolytic fuel cell - Google Patents

Abstract

PURPOSE:To make thermal expansion and contraction free to improve thermal stability by forming a unit cell in a unit cell/base body complex, which forms the module of a fuel cell, on the entire body of the outer peripheral surface of a hollow base body, and by adhering the unit cell/base body complex to the inside of the module box, in a suspended manner. CONSTITUTION:A unit cell/base body complex 18 comprises a unit cell 17 consisting of a lanthanum manganite cathode 12 provided on the entire circumference of a specific part of a cathode base body 11 which is a pipe made of lanthanum manganite, a solid electrolytic body 13 consisting of YSZ, and a Ni-YSZ anode 14. A collector 15 consisting of Pd-Pt, and a collector 16 of a Ni plate provided on the surface of the anode 14 are provided on the inside of a base plate 11. The collector 16 is placed on the anode 14 and is mounted in the axial direction for each quarter cycle, while the collector 15 is extended to the outside of the collector 18, and is connected to a Ni inter-connector 31 through a Ni felt forming the collector 16. The collectors 15, 16 of adjacent complex bodies 18 are connected together in series to improve current collecting effect and to reduce electric resistance loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cell structure of a solid oxide fuel cell, and more particularly to a single cell / substrate assembly.

[0002]

2. Description of the Related Art A fuel cell using an oxide solid electrolyte such as zirconia has a high operating temperature of 800 to 1100 ° C., and therefore has high power generation efficiency and does not require a catalyst.
In addition, since the electrolyte is solid, it is easy to handle and is expected as a third generation fuel cell.

However, the solid oxide fuel cell is
Since ceramics is the main constituent material, it is easily damaged by heat, and it is difficult to achieve it because there is no suitable gas sealing method. Therefore, as a fuel cell, a cylindrical one having a special shape has been devised, which solves the above two problems and succeeds in the operation test of the cell. FIG. 5 is a perspective view showing a cell of a conventional cylindrical solid oxide fuel cell.

An air electrode 52 made of lanthanum manganite LaMnO ₃ is laminated around a support tube 51 made of calcia-stabilized zirconia. Next, a vertically striped interconnector 55 made of lanthanum chromite LaCrO ₃ and a solid electrolyte body 53 made of yttria-stabilized zirconia YSZ are laminated. A fuel electrode 54 is provided on the solid electrolyte body 53.
However, a cell connecting portion 56 made of Ni felt is formed on the interconnector 55. Air is flown inside the support pipe 51 and fuel gas is flown outside. Since the interconnector 55 appears to have vertical stripes in the axial direction of the support tube, this type of cell is called a vertical stripe structure.

FIG. 8 is a process chart showing a conventional method for manufacturing a solid oxide fuel cell unit. A film is formed around the support tube 51, which is zirconia stabilized by calcia, by a dip method using a slurry made of lanthanum manganite LaMnO ₃ , and the air electrode 52 is laminated by firing. Next, a vertical striped interconnector 55 made of lanthanum chromite LaCrO ₃ was used for EVD (Electrochemical Vapor) using a mask.
por Deposition) method to form a film. Furthermore, YSZ (Y ₂
A solid electrolyte body 53 made of O ₃ stabilized ZrO ₂ ) is formed by an EVD method using a mask. Further, a metal Ni slurry is used to form a film by a dip method and is baked to form a skeleton of metal Ni, and then YSZ is deposited around the metal Ni by an EVD method to form a fuel electrode 54 made of Ni-YSZ. .

FIG. 6 is a sectional view showing a module of a conventional cylindrical solid oxide fuel cell. A housing 61, which is heat shielded by a heat insulating material 63 and is made of Inconel inside and stainless steel outside,
A cell 66 is supported inside the 62 via porous plates 64 and 65. Air is pumped into the cell via an air plenum. Further, hydrogen gas is flowed to the outside of the cell via the fuel plenum 67. The gas that has completed the reaction is burned in the combustion section 68 and is exhausted. The cell is supported on the porous plate 64 by nickel felt 69.

FIG. 7 is a connection diagram showing a module of a conventional cylindrical solid oxide fuel cell. This is called a bundle structure, and each cell has a Ni felt 71 and an anode bus 7.
2 and the cathode bus 73 are connected in series and in parallel. The electrical connection is made via the cell's interconnector 55. The above-mentioned conventional cylindrical solid oxide fuel cell is characterized in that the cells are free from thermal expansion and contraction, and the module does not require a gas seal.

[0008]

However, in the conventional cell manufacturing method as described above, masking and demasking are required when stacking the interconnector and the solid electrolyte body, which makes the cell manufacturing process complicated. There was a problem of becoming. Also, the cells thus prepared have vertical stripe interconnectors, which makes the cells non-uniform in the circumferential direction, which results in insufficient mechanical strength or thermal stability during thermal cycling. was there.

The present invention has been made in view of the above points, and an object thereof is to provide a solid oxide fuel cell which is easy to manufacture and has excellent mechanical strength by using a cell structure which does not require vertical stripe interconnectors. To do.

[0010]

According to the present invention, there is provided a fuel cell module, comprising: (1) a unit cell / base assembly; and (2) a module housing. The cell / base body assembly is one in which single cells are laminated on a predetermined entire circumference of the outer surface of a hollow base body, and the module housing suspends and suspends a plurality of the single cell / base body bodies together with an oxidant gas. This can be achieved by individually passing both the reaction gas of the oxidant gas and the reaction gas of the fuel gas through the inlet manifold chamber and the fuel gas inlet manifold chamber to the inside of the assembly and the single cell outside the assembly.

[0011]

When a single cell composed of a cathode, a solid electrolyte body and an anode is laminated in a predetermined circumferential direction of a substrate, masking is not required and the cell production becomes easy. Further, in the case where the base has a single cell in the entire circumferential direction, the cell is structurally mechanically uniform and mechanically strong.

Further, since the cell of the present invention is used by suspending it inside the module casing, it is free from thermal expansion and contraction and has high thermal stability of the fuel cell.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a perspective view showing a unit cell / substrate assembly of a solid oxide fuel cell according to an embodiment of the present invention. FIG. 2 shows a single cell of a solid oxide fuel cell according to an embodiment of the present invention.
It is a flowchart showing the manufacturing method about a substrate aggregate.

[0014] The cathode 12 made of lanthanum manganite LaMnO ₃ on a predetermined entire circumference of the cathode substrate 11 single cell / substrate assembly 18 is a tube made of lanthanum manganite LaMnO _3, consisting of YSZ solid electrolyte body 13 And Ni
The anode 14 made of -YSZ is sequentially stacked. The cathode 12, the solid electrolyte body 13, and the anode 14 are a single cell 17. Pd—Pt is provided inside the cathode substrate 11.
A current collector 15 made of Ni, a Ni felt, and a current collector 16 made of a Ni plate are provided on the surface of the anode 14.

Such a unit cell / substrate assembly 18 is manufactured as follows. The cathode substrate 11 is a tube made of lanthanum manganite LaMnO ₃ was immersed in the slurry made of lanthanum manganite LaMnO _3, baked to form the cathode 12 after drying. Then, while rotating the substrate, yttria-stabilized zirconia YSZ is deposited by plasma spraying to form a solid electrolyte body 13. Further Ni and Y
The anode 14 is laminated by immersing it in a slurry made of SZ, drying and firing it.

FIG. 3 is a sectional view showing a solid oxide fuel cell module according to an embodiment of the present invention. 4 shows a module of a solid oxide fuel cell according to an embodiment of the present invention, and FIG. 4 (a) is a sectional view taken along line AA of FIG.
(B) is a BB sectional view of FIG. 3. Module housing 3
Reference numeral 9 includes an oxidant gas inlet manifold chamber 32, an oxidant gas outlet manifold chamber 33, a fuel gas inlet manifold chamber 34, and a fuel gas outlet manifold chamber 35. Fuel gas is supplied from the fuel gas inlet manifold chamber 34 to the reaction chamber 37 and discharged from the fuel gas outlet manifold chamber 35. The oxidant gas is supplied to the inside of the cylindrical cell from the oxidant gas inlet manifold chamber 32, and is discharged through the oxidant gas outlet manifold chamber 33.

The unit cell / substrate assembly 18 is supported and suspended by a dense partition plate 38 which separates the oxidant gas inlet manifold chamber 32 and the fuel gas outlet manifold chamber 35. In this state, the unit cell / base assembly 18 is suspended in the vertical direction, and free thermal expansion and contraction are possible. The steam chamber 36 is provided between the fuel gas inlet manifold chamber 34 and the oxidant gas outlet manifold chamber 33. The steam in the steam chamber is set to a positive pressure with respect to the reaction gas. In this way, the oxidant gas is prevented from leaking into the fuel gas. Even if steam leaks into the fuel gas inlet manifold chamber 34, there is no problem because the fuel gas used is a fuel that requires steam reforming, such as methane. Further, even if steam leaks into the oxidant gas outlet manifold chamber 33, there is no problem because it is on the oxidant gas discharge side. Further, even if the fuel gas leaks from the fuel gas outlet manifold chamber 35 to the oxidant gas inlet manifold chamber 32, the leaking fuel gas is exhaust gas, so that it does not affect the fuel utilization rate and causes no problem in cell characteristics. Note that carbon dioxide gas, inert gas, nitrogen gas, or fuel exhaust gas may be used instead of steam.

Next, the current collection of the fuel cell will be described. The current collector 16 is a U-shaped Ni plate and a Ni felt, and is attached on the anode 14 in the axial direction every ¼ turn. The current collector 15 is excellent in oxidation resistance and conductivity, such as Pt-.
A pressure film of Pd, Ag-Pd, or the like is attached in the axial direction for every 1/4 turn inside the single cell / base assembly 18. Current collector 1
5 is extended to the outside of the unit cell / base body assembly 18 and is connected to the Ni interconnector 31 via the Ni felt 41. The Ni interconnector 31 has a ring shape and connects the current collectors 15 and 16 of the adjacent single cell / base body assembly 18 in series. Since the Ni interconnector 31 is in the reducing gas atmosphere, it does not oxidize. Ni interconnector 3
1 can be attached not only to the upper part but also to the lower part to enhance the effect of current collection. By using the current collector, the electric resistance loss of the fuel cell can be reduced.

The oxygen gas reaching the cathode 12 is reduced to oxygen ions and diffuses in the solid electrolyte body 13. Oxygen ions are oxidized on the surface of the anode 14 and react with hydrogen gas to form water vapor. At this time, a change in free energy of the reaction of producing water vapor from hydrogen gas and oxygen gas is converted into electric energy, and a negative voltage is generated at the anode 14 and a positive voltage is generated at the cathode 12. The voltage per unit cell is 0.5-0.9V.
A predetermined voltage can be obtained.

[0020]

According to the present invention, a fuel cell module having (1) a unit cell / base assembly and (2) a module housing, wherein the unit cell / base assembly is hollow. A single cell is laminated on a predetermined entire circumference of an outer surface of a base body, and a module housing suspends a plurality of the single cell / base body assembly, and an oxidant gas inlet manifold chamber and a fuel gas inlet manifold. Since both reaction gases of the oxidant gas and the fuel gas are separately passed through the chamber to the inside of the assembly and to the unit cells outside the assembly, masking is required when manufacturing the unit cell / substrate assembly. This facilitates cell manufacturing. Further, when the single cell is provided in the entire circumferential direction of the substrate, the cell is structurally uniform in mechanical strength and mechanically strong.
A substrate assembly is obtained. Further, since the single cell / base body assembly of the present invention is used by being suspended inside the module housing, it is free from thermal expansion and contraction, and the thermal stability of the fuel cell is high. In this way, a solid oxide fuel cell that is easy to manufacture and excellent in reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a unit cell / base assembly of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 2 is a process diagram showing a method for manufacturing a single cell / base assembly of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a module of a solid oxide fuel cell according to an embodiment of the present invention.

4 shows a module of a solid oxide fuel cell according to an embodiment of the present invention, FIG. 4 (a) is a sectional view taken along line AA of FIG. 3, and FIG. 4 (b) is a sectional view taken along line BB of FIG.

FIG. 5 is a perspective view showing a cell of a conventional cylindrical solid oxide fuel cell.

FIG. 6 is a sectional view showing a module of a conventional cylindrical solid oxide fuel cell.

FIG. 7 is a connection diagram showing a module of a conventional cylindrical solid oxide fuel cell.

FIG. 8 is a process chart showing a method for manufacturing a conventional solid oxide fuel cell unit.

[Explanation of symbols]

 11 Cathode Base 12 Cathode 13 Solid Electrolyte 14 Anode 15 Current Collector 16 Current Collector 17 Single Cell 18 Single Cell / Substrate Assembly 31 Ni Interconnector 32 Oxidizing Gas Inlet Manifold 33 Oxidizing Gas Outlet Manifold 34 Fuel Gas Inlet Manifold 35 Fuel Gas Outlet Manifold 36 Steam Chamber 37 Reaction Chamber 38 Partition Plate 39 Module Housing 41 Nickel Felt 51 Support Tube 52 Air Electrode 53 Solid Electrolyte Body 54 Fuel Electrode 55 Interconnector 56 Cell Connection 61 Stainless Steel Housing 62 Inconel Housing 63 Heat insulating material 64 Porous plate 65 Porous plate 66 Air plenum 67 Fuel plenum 68 Combustion part 69 Nickel felt 71 Ni felt 72 Anode bus 73 Cathode bus

Claims (7)

[Claims] 1. A fuel cell module comprising: (1) a unit cell / base assembly, and (2) a module housing, wherein the unit cell / base assembly has a predetermined outer surface of a hollow base. A single cell is laminated around the entire circumference of the module, and the module housing suspends a plurality of the single cell / base assembly, and the assembly is provided through an oxidant gas inlet manifold chamber and a fuel gas inlet manifold chamber. A solid oxide fuel cell characterized in that both reaction gases of an oxidant gas and a fuel gas are individually passed through a single cell inside the body and outside the assembly. 2. The solid oxide fuel cell according to claim 1, wherein the hollow substrate is a tube. 3. The solid oxide fuel cell according to claim 1, wherein the module casing is provided with a steam chamber for preventing leakage of both reaction gases flowing therethrough. 4. The solid oxide fuel cell according to claim 1, wherein current collectors are provided on both electrodes of the unit cell / base assembly. 5. The solid oxide fuel cell according to claim 4, wherein the unit cell / substrate assembly is connected in series with each other by a ring-shaped interconnector that presses the current collector. . 6. The solid oxide fuel cell according to claim 4, wherein the cathode current collector is Pt—Pd or Ag—Pd. 7. The solid oxide fuel cell according to claim 4, wherein the anode current collector is a Ni felt and a Ni plate.