JPH06196198A - Solid electrolyte type fuel cell - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a solid oxide fuel cell having a large area, small internal resistance, and excellent thermal stability. [Structure] A unit cell 7 and a separator 37 are laminated on two main surfaces of a cell substrate 33 having a tunnel gas flow path 34 to form an assembly 11. The aggregate 11 is laminated via a spacer 31 arranged at the center thereof. An air supply manifold 35 and an air exhaust manifold 36 pass through the stacked assembly 11 and the spacer 31, respectively. A compressible conductor 32 is inserted in the gap between the stacked assemblies 11.

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 solid oxide fuel cell having a large area and a small internal resistance.

[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.

Structurally, the solid oxide fuel cell is roughly divided into a cylindrical type and a flat plate type, and both types use ceramics as a main material. FIG. 7 is an exploded perspective view showing a conventional flat plate solid oxide fuel cell. Lantern Manganite La
A single cell 48 is formed from a cathode 46 made of MnO _3, a solid electrolyte body 44 made of yttria-stabilized zirconia YSZ, and an anode 45 made of nickel-zirconia Ni-ZrO ₂ cermet. Porous or dense lanthanum manganite LaMnO ₃ ribbed conductive substrate 41, lanthanum chromite LaCrO ₃ dense interconnector 43, porous or dense nickel-zirconia Ni-ZrO ₂ cermet ribbed conductive The separator 47 is formed from the flexible substrate 42. The unit cells 48 and the separators 47 are alternately stacked. Different gases are caused to flow in the grooves of the separator 47 that intersect three-dimensionally at right angles. The interconnector 43 separates the oxidant gas and the fuel gas. In the solid oxide fuel cell, in order to reduce the internal resistance and to increase the current, the solid electrolyte body has a large area and a small thickness (several tens to several hundreds of μm).
It is necessary to Also, for each electrode, several 100 μm is used to improve gas diffusivity and reduce electrode resistance.
It is required to be thin. Therefore, the maximum size of a single cell is limited to about 1 mm. Since the flat plate type has a high space utilization rate, the output density can be increased.

In the conventional flat plate type solid oxide fuel cell as described above, it is difficult to produce a large area battery because cracks and warps easily occur in the single cell. Further, in the conventional battery, since both the separator and the single cell contain a hard ceramic material, if the flatness and smoothness are poor, the contact resistance becomes large and the internal resistance of the battery becomes large.

Japanese Unexamined Patent Publication No. 3-55764 discloses a solid oxide fuel cell having a large area and a small internal resistance. FIG. 8 is a perspective view of a central cut main part showing a different conventional solid oxide fuel cell. This battery has a porous substrate 30 having therein a tunnel gas flow path 34 for guiding an oxidant gas.
And a single cell 7 formed by laminating an oxidizer electrode 1, a solid electrolyte body 5, and a fuel electrode 6 in this order on one main surface of the porous substrate.
A separator 37 formed by stacking on the other main surface of the porous substrate, and a separator 37 located on the periphery of the main surface of the porous substrate and functioning as a spacer when polymerizing another laminate 10. A prismatic body 13 that forms a fuel electrode space 12 that fills the fuel gas, and a compressible metal body that is placed in the fuel electrode space and that supplies the fuel gas to the fuel electrode and that electrically connects the fuel electrode and the separator. And 32. The laminated body 10 is laminated via the hollow pin 14 with a flange. The fuel filled in the fuel electrode space 12 flows through the nickel felt 32 and is then discharged through the fuel gas discharge slit 9 to react with the surrounding air and burn.

[0006]

However, in such a conventional solid oxide fuel cell, the prismatic body 13 is used.
And the laminated body 10 have different thermal expansion coefficients, the prismatic body 13 hinders the thermal expansion and contraction of the laminated body 10, and therefore the laminated body 10
There was a problem of cracking. Further, the flanged hollow pin 14 was not fitted to the manifolds of the upper and lower laminated bodies due to the positional displacement between the laminated bodies 10, which made assembly difficult. Further, the oxidant gas and the fuel gas are discharged to the periphery of the stack and burned to excessively raise the temperature around the stack, which makes it difficult to control the temperature of the stack.

The present invention has been made in view of the above points, and an object thereof is to provide a solid oxide fuel cell having a large area, low internal resistance, and excellent thermal reliability.

[0008]

According to the present invention, there is provided a support membrane type flat plate solid oxide fuel cell, comprising: (1) a cell substrate; (2) a single cell; ) A separator, (4) spacer, and (5) compressible conductor are included, the cell substrate is a conductive porous substrate, and a tunnel gas flow path through which the first reaction gas flows is provided inside. A single cell and a separator are respectively laminated on two different main surfaces while being provided, and the single cell is a solid electrolyte body, a first electrode arranged on each of the two main surfaces, and a second electrode. , Laminated on the cell substrate via the first electrode,
The separator is a conductive and dense layer, and includes a single cell, a cell substrate, and a separator that forms a single cell / cell substrate / separator assembly and penetrates a central portion of the first reaction gas supply manifold. With a reaction gas exhaust manifold of
The spacer penetrates the first reaction gas supply manifold and the first reaction gas discharge manifold, and has a groove for a sealing glass ring around the manifold, and the assembly and the reaction gas are provided at the center of the assembly. Manifolds are aligned with each other, the spacers are alternately stacked with the assembly through the unit cells and separators of the assembly, and the compressible conductor is a porous conductor and assembled with the stacked spacers. The second reaction gas is supplied to and discharged from the inserted compressible conductor, which is inserted into the body gap.
This is achieved by the fact that the aggregate, the spacer and the compressible conductor form a stack.

[0009]

Since the unit cell is directly formed on the main surface of the cell substrate, the unit cell is fixed on the surface of the cell substrate and warpage is prevented even in the case of a large area. Since the compressive conductor is well fitted to the surface to be electrically connected and crimped, the contact resistance between the aggregates is reduced.

A spacer arranged in the center of the assembly,
Since the aggregate is laminated via the compressive conductor inserted in the peripheral portion, the thermal expansion and contraction of the aggregate is free.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. Example 1 FIG. 1 is a perspective view of a central cut main part showing a solid oxide fuel cell according to an example of the present invention.

FIG. 2 is a sectional view of the solid oxide fuel cell shown in FIG. 1, taken along the line AA. FIG. 3 is a plan view showing a spacer of the solid oxide fuel cell according to the embodiment of the present invention. FIG. 4 is a sectional view showing a spacer of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 5 is a sectional view showing a stack of a solid oxide fuel cell according to an embodiment of the present invention. Diameter 300
mm, 6 mm thick lanthanum manganite LaMnO ₃ cell substrate 33 has a tunnel gas flow passage 34 in which air flows.
Are formed concentrically and radially. The tunnel gas flow path 34 communicates with an air supply manifold 35 and an air exhaust manifold.

Lanthanum manganite LaMnO ₃ was sprayed onto one main surface of the cell substrate 33, and the porous cathode 4 was formed into one.
It is formed to a thickness of 00 μm. This cathode is the cell substrate 3
Since it is the same material as No. 3, it can be omitted. On the cathode 4, dense yttria-stabilized zirconia YSZ is sprayed to a thickness of 100 μm to form the solid electrolyte body 2. The yttria-stabilized zirconia YSZ is also sprayed on the outer surface of the cell substrate to make the outer surface airtight. Subsequently, nickel oxide-zirconia NiO-ZrO ₂ is sprayed, and the porous anode 3 is formed to have a thickness of 100 μm. The sprayed nickel oxide-zirconia NiO-ZrO ₂ is reduced by hydrogen gas during the operation of the fuel cell and is active nickel-zirconia Ni-ZrO 2.
It becomes ₂ cermets.

On the other main surface of the cell substrate 33, lanthanum chromite LaCrO ₃ is sprayed and a separator 37 is densely formed. An air supply manifold 3 is provided at the center of the cell base 33.
5 and an air exhaust manifold 36 are formed. A part of the air flowing through the air supply manifold 35 flows through the tunnel gas flow path 34 inside the cell substrate 33, reaches the cathode 4, and is then discharged by the air discharge manifold 36.

The spacer 31 has a diameter of 100 mm and a thickness of 2 m.
m alumina disk with an air supply manifold and an air exhaust manifold inside. These two manifolds match the manifold of the assembly 11 when the spacer 31 is laminated to the assembly 11. A glass ring groove 39 is provided in the spacer 31 for gas sealing, and the glass ring is fitted therein. The glass ring melts at the operating temperature and a gas seal is formed. The air supply manifold and the air discharge manifold are respectively the air supply pipe 1 described later.
5 and the air exhaust pipe 16.

The spacers 31 are laminated alternately with the aggregates 11 via the unit cells of the aggregates and the separators to form a stack 27. The spacer 31 is mounted by assembling the reaction gas manifolds in the central portion of the assembly 11 so as to match each other.
Assembly is easy, and the stress generated inside the assembly due to the difference in the thermal expansion coefficient between the assembly 11 and the spacer 31 is limited to a small area in the center of the assembly. This greatly reduces the cracking of the aggregate.

The nickel felt 32 is the above-mentioned stack 27.
Is inserted in the gap between the assembly and the spacer to electrically connect the separator 37 and the anode 3 of the different assembly. The nickel felt 32 is stable and compressible in a reducing atmosphere, and during compression, it is well adapted to the surface state of the compression surface and reduces the contact resistance between the aggregates. The nickel felt 32, together with the spacer 3 placed at the center of the assembly, allows the assembly to thermally expand freely, so that the thermal stability of the fuel cell stack is enhanced.

FIG. 6 is a perspective view showing a module of a solid oxide fuel cell according to an embodiment of the present invention. The upper and lower surfaces of the stack 27 are sandwiched by the upper end plate 25 and the lower end plate 26. The stack 27 and these end plates are magnetic cylindrical containers 53.
Are stored through the alumina felts 21, 22, 23, and 24. Alumina felts 21 and 22 are inserted on the side wall of the stack leaving two spaces. Alumina felts 23 and 24 are inserted above and below the upper end plate 25 and the lower end plate 26, respectively. The two spaces serve as a manifold for supplying and discharging the fuel gas. This manifold is connected to a fuel gas supply pipe 17 and a fuel gas discharge pipe 18, respectively. Fuel gas is supplied from the fuel gas supply manifold 19 to the anode 3 via the nickel felt 32. Excess fuel gas passes through the fuel gas exhaust manifold 20 and the fuel gas exhaust pipe 1
Emitted from 8. The upper end plate 25 and the lower end plate 26 function as a current collector plate of the stack 27. The stack 27 is pressed by the cover plate 40 via the alumina felts 23 and 24,
Adhesion between the aggregate 11 and the spacer 31 is enhanced.

Since the oxidant gas and the fuel gas are separately supplied and discharged by the reaction gas supply manifold and the reaction gas discharge manifold, the oxidant gas and the fuel gas do not burn around the fuel cell due to the discharge and Temperature control becomes easy. Instead of lanthanum manganite LaMnO ₃ Nickel in Example 2 cell substrate 33 - zirconia Ni-ZrO ₂ cermet used. Nickel oxide-zirconia NiO-ZrO ₂ was sprayed on one main surface of the cell substrate 33, and 100 porous anodes were formed.
It is formed to a thickness of μm. Then, a dense yttria-stabilized zirconia YSZ is sprayed to a thickness of 100 μm to form a solid electrolyte body. Subsequently, lanthanum manganite LaMnO ₃ is sprayed to form a porous cathode with a thickness of 100 μm. The anode can be omitted because it is the same material as the cell substrate. Nickel oxide-zirconia NiO-ZrO ₂
Is reduced by hydrogen gas during operation of the fuel cell to become active nickel-zirconia Ni-ZrO ₂ cermet.

A fuel gas supply manifold and a fuel gas exhaust manifold are formed in the central portion of the cell base 33 in place of the air supply manifold and the air exhaust manifold. Indium oxide felt instead of the nickel felt 32 is inserted in the gap between the stack assembly and the spacer to electrically connect the separator and the anode of the different assembly. Indium oxide oxide is stable in an oxidizing atmosphere.

Others are the same as in the first embodiment.

[0023]

According to the present invention, there is provided a support membrane type flat plate type solid oxide fuel cell, comprising: (1) a cell substrate;
(2) A single cell, (3) separator, (4) spacer, and (5) compressible conductor are included, the cell substrate is a conductive porous substrate, and the first reaction gas is inside. Is provided with a tunnel gas flow path through which a single cell and a separator are respectively laminated on two different main surfaces on the outside, and the single cell is a solid electrolyte body and a first electrode arranged on each of the two main surfaces. An electrode and a second electrode, which are laminated on the cell substrate via the first electrode, a separator is a conductive and dense layer, and the unit cell, the cell substrate, and the separator are unit cells / A first reaction gas supply manifold, which forms a cell base / separator assembly and penetrates through the central portion, and a first reaction gas discharge manifold, and the spacer is the first reaction gas supply manifold and the first reaction gas. With the exhaust manifold penetrating A groove for a sealing glass ring is provided around the manifold, and the assembly and the reaction gas manifold are arranged in the central portion of the assembly so as to be aligned with each other, and the spacer is disposed through the unit cell and the separator of the assembly. Are alternately laminated with the aggregate, and the compressible conductor is a porous conductor and is inserted in the gap between the laminated spacer and the aggregate.
The second reaction gas is supplied to and discharged from the inserted compressive conductor, and the aggregate, the spacer, and the compressible conductor form a stack, so that the unit cell is a cell. It is fixed directly to the main surface of the substrate, and warpage is prevented even in the case of a large area. Since the compressive conductor is well fitted to the surface to be electrically connected and crimped, the contact resistance between the aggregates is reduced. Furthermore, since the aggregate is laminated with the spacer and the compressible conductor, the thermal expansion and contraction are free and the thermal reliability is enhanced. In this way, a solid oxide fuel cell having a large area, low internal resistance and excellent reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a central cut main portion showing a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 2 is a sectional view of the solid oxide fuel cell shown in FIG. 1, taken along the line AA.

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

FIG. 4 is a sectional view showing a spacer of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 5 is a sectional view showing a stack of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 6 is a perspective view showing a module of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a conventional flat plate solid oxide fuel cell.

FIG. 8 is a perspective view of a center cut main part showing a different conventional flat plate solid oxide fuel cell.

[Explanation of symbols]

 1 Oxidizer Electrode 2 Solid Electrolyte Body 3 Anode 4 Cathode 5 Solid Electrolyte Body 6 Fuel Electrode 7 Single Cell 8 Slit 9 Fuel Gas Discharge Slit 10 Laminated Body 11 Aggregate 12 Fuel Electrode Space 13 Prism 14 Hollow Body with Flanges 15 Air Supply Pipe 16 Air exhaust pipe 17 Fuel gas supply pipe 18 Fuel gas exhaust pipe 19 Fuel gas supply manifold 20 Fuel gas exhaust manifold 21 Alumina felt 22 Alumina felt 23 Alumina felt 24 Alumina felt 25 Upper end plate 26 Lower end plate 27 Stack 30 Porous substrate 31 Spacer 32 Nickel felt 33 Cell substrate 34 Tunnel gas flow channel 35 Air supply manifold 36 Air exhaust manifold 37 Separator 39 Glass ring groove 40 Lid plate 41 Conductive substrate with ribs 42 Conductive substrate with ribs 43 In Connector 44 solid electrolyte body 45 anode 46 cathode 47 separator 48 single cell

Claims (11)

[Claims] 1. A support membrane type flat plate solid oxide fuel cell, comprising: (1) a cell substrate, (2) a single cell, (3) a separator, (4) a spacer, and (5) compression. And a conductive base material, the cell substrate is a conductive porous substrate, and a tunnel gas flow path through which the first reaction gas flows is provided inside and a single cell on two different main surfaces outside. And a separator are laminated respectively, and the single cell is a solid electrolyte body, a first electrode and a second electrode respectively arranged on both main surfaces of the solid electrolyte body. Stacked, the separator is a conductive and dense layer, the unit cell, the cell substrate, and the separator is the unit cell / cell substrate / separator assembly and the first reaction gas supply manifold penetrating the central portion. , A first reaction gas exhaust manifold, The first reaction gas supply manifold and the first reaction gas discharge manifold pass through, and a groove for a sealing glass ring is provided around the manifold, and the assembly and the reaction gas are provided at the center of the assembly. Manifolds are placed in line with each other, the spacer is through the unit cell and separator of the assembly,
The compressible conductors are laminated alternately with the aggregate, and the compressible conductor is a porous conductor and is inserted into the gap between the laminated spacer and the aggregate. A solid oxide fuel cell, in which a reaction gas is supplied and discharged, and the assembly, the spacer, and the compressible conductor form a stack. 2. The solid oxide fuel cell according to claim 1, wherein the stack is housed in a box via a compressible insulator. 3. The fuel cell according to claim 2, wherein the compressible insulator is disposed on the upper and lower sides of the stack and on the side wall so as to be separated from each other, leaving two spaces for the side wall serving as a second reaction gas supply and discharge manifold. And a solid oxide fuel cell. 4. The solid oxide fuel cell according to claim 1, wherein the first reaction gas is an oxidant gas and the second reaction gas is a fuel gas. 5. The solid oxide fuel cell according to claim 4, wherein the first electrode and the cell substrate are both lanthanum manganite LaMnO ₃ . 6. The solid oxide fuel cell according to claim 1, wherein the first reaction gas is a fuel gas and the second reaction gas is an oxidant gas. 7. The fuel cell according to claim 6, wherein the first electrode and the cell substrate are both nickel-zirconia Ni-Z.
A solid oxide fuel cell, which is a cermet made of rO ₂ . 8. The solid oxide fuel cell according to claim 1, wherein the cell substrate also serves as the first electrode. 9. The solid oxide fuel cell according to claim 1, wherein the separator is lanthanum chromite LaCrO ₃ . 10. The solid oxide fuel cell according to claim 4, wherein the compressible conductor is Ni felt. 11. The solid oxide fuel cell according to claim 6, wherein the compressible conductor is indium oxide oxide.