JPH08250133A - Cell structure and high temperature solid electrolytic fuel cell thereof - Google Patents

Abstract

PURPOSE: To provide a cell structure, realizing the strength improvement of the seal portion, etc., of an electrolyte membrane (ion exchange membrane) suitable to be used for a high-temperature steam electrolysis (SOE: Solid Oxide Electrolyte) using a solid electrolyte and a solid electrolytic fuel cell (SOFC: Solid Oxide Fuel Cell), and a high temperature solid electrolytic fuel cell using the cell structure. CONSTITUTION: Fuel and air electrodes 12 and 13 are arranged on both the surfaces of an electrolyte membrane 11 to constitute a power generating membrane 14. The shape of the membrane 14 is made corrugation, and also an interconnector 15 having electron conductivity and a gas shut-off property, and a sealing member 16 having a nearly U-shaped cross section, are integrally joined on the surface side of one electrode 13 of the membrane 14 and on the lower end part of the interconnector 15 respectively, to arrange a metallic material 17, in an unrestrictive condition, on the surface side of the other electrode 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to high temperature steam electrolysis (SOE) using a solid electrolyte and a solid oxide fuel cell (SOFC).
The present invention relates to a cell structure for improving the strength of a seal portion of an electrolyte membrane (ion exchange membrane) suitable for use in a battery and a high temperature solid electrolyte fuel cell using the same.

[0002]

2. Description of the Related Art A fuel cell supplies fuel such as hydrogen and an oxidant such as air to both sides of an electrolyte to generate electric power. Generally, there are a cylindrical type and a flat type, and a flat type among them. Since it can be operated at high current density and has good volume efficiency, it is expected to be put to practical use. As a representative configuration example, FIG. 6 shows an example of an external manifold type fuel cell and FIG. 7 shows an example of an external manifold type fuel cell.

As shown in FIG. 6, an external manifold type fuel cell has a box type air introduction manifold 02A and a fuel introduction manifold 02B, an air discharge manifold 03A and a fuel on its side surface after the fuel cell cell stack 01 is assembled. This is a structure in which each discharge manifold 03B is installed. On the other hand, in the internal manifold type fuel cell, as shown in FIG. 7, since the gas introduction / exhaust portion is provided in the cell 04, the unit cell is assembled and the introduction pipes 05A and 05B and the discharge pipe 06A are joined from the lower part. By doing so, a fuel cell is constructed.

[0004]

By the way, in the case of the above-mentioned conventional fuel cell, the sealing property is obtained by joining the unit cells.

If this junction is perfect, no leak will occur and good characteristics can be obtained. However, there are the following problems in the prior art. In order to completely join the unit cells and withstand the temperature change during operation / stop, the thermal expansion coefficients of the constituent members must be completely the same. In addition, an operation that does not cause a large difference in temperature during operation is required.

In view of the above-mentioned problems, the present invention has made the operation of matching the thermal expansion coefficient and the operation of reducing the temperature difference during operation more lenient so that the thermal expansion coefficient can be improved even if there is a slight temperature difference. It is an object of the present invention to provide a cell structure that enables manufacture and operation of a solid oxide fuel cell even if they are different, and a high temperature solid electrolyte fuel cell using the cell.

[0007]

A solid oxide fuel cell according to the present invention, which achieves the above object, is a cell in which a fuel electrode and an air electrode are arranged on both sides of an electrolyte membrane to form a power generation membrane or an electrolyte membrane. In the structure, the electrolyte membrane has a corrugated shape, and a fuel electrode and an air electrode are arranged on both sides thereof, and an interconnector having electronic conductivity and gas blocking property on one air electrode surface side of the power generation membrane. Are integrally joined, and a metallic material is arranged on the other fuel electrode surface side in an unconstrained state.

In the above cell structure, an air introducing pipe is provided between the air electrode surface of the power generating membrane and the interconnector, and fuel gas and air are supplied to the respective electrodes in the same direction, and the air introducing pipe is introduced. Before the air is supplied through the tube, the air is supplied from the direction opposite to the film supply direction and residual heat is generated.

In the above cell structure, the metal material is N
It is characterized in that it is a simple metal mesh or alloy of i, Pt, Co, Cr, a mesh, a felt, or a porous body.

On the other hand, the structure of the high temperature solid electrolyte fuel cell according to the present invention is a high temperature solid electrolyte fuel cell in which a fuel such as hydrogen and an oxidizing agent such as an air electrode are supplied to both sides of the solid polymer electrolyte to generate electricity. Therefore, the cell according to any one of claims 1 to 3 is arranged in a power generation chamber, two opposite sides of the four sides of the cell are sealed and gas-shielded, and the other one side is opened to the combustion chamber side and air is provided. An introduction pipe is provided penetrating to the air electrode side, and one side facing the other side seals an end portion thereof and arranges a header seal member for dispersing gas, and a plurality of cells are provided through the metal material. It is characterized by being arranged.

That is, in the present invention, the shape of the power generation membrane is a wave shape, and the gas (fuel and air) flows in one direction. Conventionally, the unit cells are constrained from above and below by being laminated and joined, but in the present invention, the unit cells are unconstrained by being sandwiched by non-constraining conductive substances such as metal felt. It is necessary to supply gas to the unit cells, but this is done by using a gas introduction pipe that also functions as a heat exchanger on the air side and by making the entire cell stack into a fuel atmosphere on the fuel side.

[0012]

The air is introduced downward from the gas introduction pipe and exchanges with the energy of the combustion exhaust gas to generate residual heat. The preheated air enters the cell and descends while receiving the heat generated in the cell. The air that has reached the bottom of the cell flows laterally and subsequently rises on the cathode side in the cell. Oxygen is consumed here for power generation. The remaining air enters the combustion chamber where it undergoes combustion reaction with unreacted fuel and becomes exhaust gas. One of the introduced fuels is supplied to the surface of the fuel electrode along the metal felt and flows upward.

Power generation is performed by introducing the fuel gas into one of the power generation membranes and the oxidizing gas (air) into the other in the above-described procedure. The current extracted by this power generation flows into the next cell through the metal felt, the voltage is further increased, and finally it is extracted to the external circuit.

[0014]

EXAMPLES A preferred example of the present invention will be described below, but the present invention is not limited thereto.

FIG. 1 is a block diagram of a fuel cell according to this embodiment. 2 and 3 are schematic configuration diagrams of a main part thereof. FIG.
3 is a diagram illustrating a method of assembling a cell member of a fuel cell according to the present embodiment. FIG. 5 is a drawing showing the flow of fuel gas in the fuel cell according to the present embodiment.

As shown in FIG. 2, a cell 1 according to the present embodiment.
0 is a fuel electrode 12 and an air electrode 13 on both sides of the electrolyte membrane 11.
Are arranged to form the power generation film 14, and FIG.
As shown in FIGS. 3 and 4, the electrolyte membrane 14 has a wavy shape.

Further, one air electrode 13 of the power generation film 14 is used.
On the surface side, an interconnector 15 having electronic conductivity and gas blocking property and a seal member 16 having a substantially U-shaped cross section are integrally joined to the lower end portion thereof, and the other fuel electrode 1
The metal material 17 is arranged on the second surface side in an unconstrained state.

Further, an air introducing pipe 18 is arranged between the surface of the air electrode 13 of the power generation membrane 14 and the interconnector 15, and each of the electrodes 12 and 13 is arranged in the same direction (in the present embodiment). While supplying the fuel gas 19 and the air 20 from the lower side to the upper side in the example), the air 20 is introduced from the direction opposite to the supply direction (in the present embodiment, from the upper side to the lower side) before the supply. By being introduced through the pipe 18, it is supplied while remaining heat.

Further, as shown in FIGS. 1 and 3, in the power generation chamber main body 21 for accommodating the cells, two partition members 25 and 26 are provided for a combustion chamber 22, an air chamber 23 and a fuel chamber 24.
Is divided into three parts, and the cell 10 is composed of the interconnector 15 and the metal felt 17 as one unit so as to sandwich the corrugated power generation film 11 in the power generation chamber 21.

That is, in the high temperature solid oxide fuel cell according to the present embodiment, as shown in FIGS. 1 and 3, the cells are arranged in the power generation chamber 21 and the four sides of the power generation membrane 14 on both sides facing each other. Two sides are sealed and gas is blocked, one side is opened to the combustion chamber 22 side, and an air introduction pipe 18 is provided so as to penetrate to the air electrode side. One opposite side seals the end portion and disperses gas. End seal portion 1 as a header seal member
6 are arranged, and a plurality of unit cells are arranged through a metal material 17.

Further, as shown in FIGS. 1 and 2, the end seal portion 16 for sealing the end portion provided at the lower end portion of the corrugated power generation membrane 14 guides the introduced air 20 in the lateral direction and forms each corrugation. It serves as a header for supplying the air 20 to the surface of the air electrode 13.

Further, as shown in FIGS. 2 and 3, when the lower end portion of the upper power generation membrane 14 is sealed using the end seal portion 16, air 20 from the fuel electrode 13 side to the fuel electrode 12 side is sealed. A sealing material 27 is provided to prevent communication between the fuel electrode 12 and the fuel electrode 12, and only the fuel 19 is supplied to the surface of the fuel electrode 12. The supplied fuel 19 is introduced through a plurality of small holes 28 provided in the partition member 26 for separating the fuel chamber 24 and the combustion chamber 22. This small hole 28 may be provided at a position corresponding to the corrugation of the power generation film 14, but is not limited to this.

A method for assembling the above fuel cell members will be described below. As shown in FIG. 4, an interconnector 15 is arranged on the air electrode side of a corrugated power generation membrane 14 having a fuel electrode and an air electrode formed on both sides, and a metal felt 17 is arranged on the fuel electrode 12 side to form a power generation cell. It is what constitutes. In this embodiment, two air introduction pipes 18 are provided between the air electrode and the interconnector 15, and the lower end portion of the power generation membrane 14 is filled with the end seal portion 16 and the filling material 27 to form a unit cell. Are fired and joined together. Next, as shown in FIGS. 1 and 3, a fuel cell stack 29 is formed by sequentially stacking the fired unit cells in the power generation chamber 21 via the metal felt 17.

According to the fuel cell having the above structure, (1) it is possible to provide a solid fuel cell having an excellent yield. That is, the cells 10 in the cell group are independent of each other and can be individually fired and inspected, so that the yield is improved. (2) Excellent maintainability. That is, since the cells 10 in the cell group are independent of each other and can be individually inspected and inspected, it is possible to deal with it by replacing only the defective cell 10 and the maintainability is excellent. is there. (3) Excellent in durability and temperature recycling. That is, since the non-contact metal felt 17 absorbs the stress generated by the nonuniform temperature of the cell 10 by the deformation, the stress generated by the rapid temperature increase / decrease or the high current density operation is small.

The flow of gas on the air electrode side will be described below with reference to the drawings. As shown in FIGS. 1 and 3, first, the air 20 introduced into the air chamber 23 from the outside is introduced downward from the air introduction pipe 18 and penetrates the combustion chamber 22 on the way. Thus, the residual heat of the air 20 is exchanged with the energy of the combustion exhaust gas. When the surplus-heated air 20 passes near the surface of the power generation film 14, it also descends in the air introduction pipe while receiving the combustion heat generated in the cell. The sufficiently preheated air 20 reaching the lowermost portion of the power generation membrane 14 comes into contact with the end seal portion 16 and, as a result, flows in the lateral direction, and subsequently rises on the surface side of the air electrode 13 of each corrugation. Oxygen is consumed here for power generation.
The remaining air 20 enters the combustion chamber 22 where it undergoes a combustion reaction with the unreacted fuel 19 at one fuel electrode 12,
It becomes exhaust gas and is discharged to the outside.

Next, the flow of the fuel gas will be described. As shown in FIGS. 2 and 5, the fuel 19 is introduced into the fuel chamber 24 from the outside, and enters the combustion chamber 22 in which the power generation membrane 14 is housed from the small hole 28 provided in the partition member 26 above the fuel 19. . The introduced fuel 19 flows upward along the metal felt (one side of which is in contact with the interconnector of the other cell and the other side is in contact with the fuel electrode 12 of the power generation membrane 14).

(2) Power Generation Power is generated by introducing the fuel gas 19 to one side of the power generation membrane 14 and the air 20 as an oxidizing gas to the other side according to the procedure described above. The current extracted by this power generation flows into the next unit cell through the metal felt 17 provided on the fuel electrode side, the voltage is further increased, and finally, the current extraction plate (not shown) (the metal plate of FIG. 1 is used). Placed at the right and left ends of the group), and taken out to an external circuit.

Next, a specific example of the above configuration will be described. The air introduction tube 18 is an alumina tube having an outer diameter of 1.5 mm, an inner diameter of 1 mm and a length of 30 cm. Power generation membrane 14 is 200m
It is made of YSZ (yttria-stabilized zirconia) of m × 200 mm and has a sinusoidal corrugated plate with a pitch of 3 mm.
A fuel electrode 12 (NiO / YSZ) is provided on one side, and an air electrode 13 (LaMnO ₃ is added with Sr and is an electrically conductive oxide on one side thereof. It is abbreviated as LSM, and its typical composition is La.
_{It is 0.9} Sr _0.1 Mn ₃ . ) Is applied and baked for about 50 μm.

The interconnector 15 has a thickness of 2 mm and 200
It is a rectangle of mm × 210 mm. The end seal portion 16 has a substantially U-shaped cross section, is made of an insulating material such as zirconia or alumina, and has a function as an air header.

This was assembled as shown in FIG. 4, the joint portion was sealed with a joint material, and after filling the seal material 27, the unit cell was completed by firing at 1000 to 1400 ° C. Next, the power generation chamber 21 having a heat insulating layer
The stack is completed by sequentially laminating the metal felts 17 therein.

Examples of the metal material 17 include Ni mesh, stainless steel mesh, Cr mesh, Fe.
Examples thereof include, but are not limited to, a simple substance such as a mesh, an Inconel mesh, an Incoloy mesh, a Co mesh, and a Pt mesh, or an alloy. In addition to the metal mesh, a porous body made of these metals or a felt made of fine wires of these metals can be used.

In this embodiment, the cell of the electrolyte membrane (ion exchange membrane) suitable for the solid oxide fuel cell (SOFC) has been described above.
The present invention is not limited to this, and the present invention is directed to high temperature steam electrolysis (SOE: Solid Oxide) using a solid electrolyte.
Electrolyte) It can also be applied to cell structures that improve the strength of the cell seals.

[0033]

As described above, according to the present invention, (1) a solid fuel cell having an excellent yield can be provided. That is, in the conventional solid electrolyte fuel cell, it is difficult to fire, and it was necessary to discard the whole when some cells were incomplete, but according to the present invention, the cell groups are independent,
Moreover, since the firing and the inspection can be performed individually, the yield is improved. (2) Excellent maintainability. In other words, when a conventional solid electrolyte fuel cell is operated, if cracks occur in some members, the temperature rises at the cracks and eventually the entire cell may be damaged. However, although it was necessary to replace the entire cell, according to the present invention, since each cell group is independent and can be individually inspected and inspected, it is possible to deal with it by replacing only the defective cell. This is because it becomes possible to improve the maintainability. (3) Excellent in durability and temperature recycling. That is, in the cell according to the present invention, the stress generated due to the non-uniform temperature is absorbed by the deformation of the metal felt, so that the stress generated due to the rapid temperature increase / decrease and the operation at the high current density can be small. is there.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a fuel cell according to an embodiment.

FIG. 2 is a configuration diagram of a fuel cell according to the present embodiment.

FIG. 3 is a configuration diagram of a fuel cell according to the present embodiment.

FIG. 4 is a diagram illustrating a method of assembling the members of the fuel cell according to the present embodiment.

FIG. 5 is a diagram showing a gas flow of the fuel cell according to the present embodiment.

FIG. 6 is a configuration diagram of a fuel cell according to a conventional example.

FIG. 7 is a configuration diagram of a fuel cell according to a conventional example.

[Explanation of symbols]

 10 Cell 11 Electrolyte Membrane 12 Fuel Electrode 13 Air Electrode 14 Power Generation Membrane 15 Interconnector 16 End Seal Part 17 Metal Material (Metal Felt) 18 Air Inlet Tube 19 Fuel Gas 20 Air 21 Power Generation Chamber Main Body 22 Combustion Chamber 23 Air Chamber 24 Fuel Chamber 27 Seal material 28 Small hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hikaru Kitamura 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (72) Inventor Tokumi Satake Hyogo-ku, Kobe-shi, Hyogo 1-1-1 Wadazakicho Mitsubishi Heavy Industries Ltd. Kobe Shipyard

Claims (4)

[Claims] 1. A cell structure in which a fuel electrode and an air electrode are arranged on both sides of an electrolyte membrane to form a power generation membrane or an electrolyte membrane, and the electrolyte membrane has a corrugated shape with a fuel electrode and an air electrode on both sides. In addition, an interconnector having electronic conductivity and gas blocking property is integrally joined to one air electrode surface side of the above-mentioned power generation membrane, and a metal material is unconstrained on the other fuel electrode surface side. A cell structure characterized by being arranged. 2. The cell structure according to claim 1, wherein an air introduction pipe is arranged between the air electrode surface of the power generation membrane and the interconnector, and fuel gas and air are supplied to each electrode from the same direction. In addition, the cell structure is characterized in that the air is supplied from the direction opposite to the film supply direction and residual heat is supplied before the air is supplied by the air introduction pipe. 3. The cell structure according to claim 1 or 2, wherein the metal material is a simple metal mesh or alloy of Ni, Pt, Co, Cr, a mesh, felt, or a porous body. 4. A high-temperature solid electrolyte fuel cell in which a fuel such as hydrogen and an oxidant such as an air electrode are supplied to both sides of a solid polymer electrolyte to generate electric power, and the cell according to any one of claims 1 to 3 is used in the power generation chamber. Of the four sides of the cell, two sides on opposite sides of the cell are sealed and gas-shielded, and the other side is opened to the combustion chamber side and the air introduction pipe is provided so as to penetrate to the air electrode side. A high-temperature solid electrolyte characterized in that one side facing the other side has a header sealing member for sealing the end portion thereof and dispersing gas, and a plurality of cells are arranged through the metal material. Fuel cell.