JPH08127888A - Cell structure - Google Patents

Abstract

PURPOSE: To develop highly efficient steam electrolyzer and fuel cell by laminating plural unit cells each provided with a cathode and an anode on both sides of a specified solid electrolyte so that the facing of the anodes and that of the cathodes are alternately provided. CONSTITUTION: A unit cell 13 provided with a cathode 12A and an anode 12B is laminated on both sides of a solid electrolyte 11 consisting of Y2 O3 -stabilized ZrO2 (YSZ) through a ceramic ring 21 so that the facing of the anodes and that of the cathodes are alternately provided at regular intervals in the thickness direction of the electrolyte, and further a cathode reaction passage 22A and an anode reaction passage 22B are alternately formed. Steam and air are supplied respectively to the cathode 12A and anode 12B to decompose the steam into hydrogen and oxygen by utilizing the characteristic of the YSZ permeable only to O2 , or gaseous hydrogen is passed on the cathode side and gaseous oxygen on the anode side to generate an electric power between both electrodes with high reaction efficiency.

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).
ell) and suitable cell structure.

[0002]

2. Description of the Related Art The structure of a flat plate type electrolysis cell is shown in FIG. 5 as an example of a high temperature steam electrolysis cell. As shown in the figure, the cathode 12A and the anode 12B are attached to both surfaces of the solid electrolyte 11 to form the unit cell 13,
Further, one of them is connected to a collector 14 and an interconnector (also separator) 15 is used to form a joined body. A plurality of groove portions 16 for supplying a fluid such as gas or water vapor are formed in the interconnector 15 so that the gas or water vapor respectively flows in the groove direction, and the single cells adjacent to each other in the plate thickness direction of the electrolyte 11 are formed. The anode and the cathode are electrically connected and the gas is separated. Also, single cell 1
3 is supported by a ceramic support plate (manifold) 18 via a sealant 17, and the interconnector 1
5 is an electrolytic cell formed by stacking a plurality of single cells via a fastening member (not shown) (such as a ceramic bolt).

Next, a principle diagram of steam electrolysis is shown in FIG.
The solid electrolyte 11 used here is zirconia (YSZ) stabilized with yttria. This YSZ has a property of selectively permeating only oxygen ions (O ²⁻ ), and as shown in FIG.
Water vapor (H ₂ O) is supplied to the 2A side and oxygen (O ₂ ) is supplied to the anode electrode 12B side, and a current is supplied from an external DC power source 19 to generate oxygen ions (O ₂ ) in the solid electrolyte 11.
^2- ) Only move.

The supplied water vapor (H ₂ O) is depleted of oxygen ions (O ²⁻ ) and becomes only hydrogen (H ₂ ), and the oxygen ions (O ²⁻ ) moved in the solid electrolyte 11 are the anode electrodes. Emitting electron (e ⁻ ) at 12B, oxygen gas (O ₂ )
Becomes In this way, water vapor (H ₂ O) can be decomposed (electrolyzed) into oxygen gas (O ₂ ) and hydrogen gas (H ₂ ) by using YSZ for the solid electrolyte 11, and oxygen (O ₂ ) can be generated by electrolysis. ₂ ) and hydrogen (H ₂ ) can be obtained.

A solid polymer electrolyte fuel cell has a similar structure, and its principle is shown in FIG. The solid electrolyte 11 used here is zirconia (YSZ) stabilized with yttria. This YSZ is
It has a property of selectively permeating only oxygen ions (O ²⁻ ), and when hydrogen and oxygen (or air) are supplied to each of the electrodes 12A and 12B and an oxygen partial pressure difference is given, oxygen ions (O 2 Only ^2- ) moves and takes out the transfer of electrons at the electrodes to the outside, so that power can be generated and the lamp etc. can be turned on.

[0006]

By the way, in the prior art, as shown in FIG. 5, a plurality of layers are laminated in the same direction as the plate thickness direction of the cell via an interconnector (separator) 15, and the current path thereof is an electrolyte. Since it flows in one direction of the plate thickness direction, a separator 15 for separating gas is required between each cell. In this case, the gas flow path is composed of a separator and a single cell, but since the separator 15 is merely a gas separation membrane, only half the area of one gas flow path acts as a reaction surface. There's a problem. The above is the same for the cell structure of the fuel cell shown in FIG. 7, which has a cell structure similar to that of the electrolysis cell.

In view of the above problems, it is an object of the present invention to effectively utilize the electrode area, improve the output per unit volume of the cell, and provide a cell structure with high reaction efficiency.

[0008]

A cell structure according to the present invention which achieves the above object has a cathode electrode and an anode electrode disposed on both surfaces of an electrolyte, and a cathode fluid and an anode fluid are provided to these electrodes. In the cell structure in which each is supplied, a cathode electrode and an anode electrode are arranged on both surfaces of the electrolyte to form a single cell, and the single cell is alternately arranged with the cathodes facing each other and the anodes facing each other. As described above, the cathode reaction passage and the anode reaction passage are formed by stacking at a predetermined interval. In the stacking direction of the unit cell, for the cathode and the cathode for supplying and discharging the fluid to the cathode electrode and the anode electrode, respectively. A fluid supply passage and a fluid discharge passage for the anode are formed so as to penetrate therethrough, and a fluid supply passage and a fluid discharge passage for the cathode and the anode are formed. Cathode electrodes and anode electrodes are connected to the cathode reaction passage and the anode reaction passage, respectively, and holes are formed in each electrolyte to be a current passage, and a cathode electrode is formed through a conductive material. And is electrically connected to the anode electrode.

In the cell structure having the above structure, the plurality of laminated single cells are characterized in that they are laminated at a predetermined interval via ceramic rings so that cathodes and anodes face each other.

In the cell structure having the above configuration, the electrical connection is made through an interconnector and a conductive agent.

In the cell structure having the above structure, in a plurality of stacked unit cells, the anode electrode provided on the electrolyte of the unit cell of the first layer is electrically connected to the cathode electrode of the unit cell of the second layer, The anode electrode provided on the electrolyte of the second unit cell is electrically connected to the cathode electrode of the unit cell of the second layer, and this connection is sequentially performed.

In the cell structure having the above structure, the electrolyte is Y
It is characterized by being used for a flat plate type high temperature steam electrolysis cell made of SZ (Yttria Stabilized Zirconia).

The cell structure of the above construction is characterized in that the electrolyte is used in a cell of a fuel cell using a solid electrolyte.

[0014]

In the above structure, since the gas is separated by the electrolyte plate, it is not necessary to provide a partition plate, a separator or the like for gas separation as in the conventional case, and both sides of the gas flow path are connected to the reaction surface. Since it can be used, the output per unit deposition of the cell can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the cell structure according to the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a schematic cross-sectional view of the cell structure according to this embodiment, showing the AA cross-sectional view of FIG. 2, and FIG. 2 is a perspective view from the top of the cell structure according to this embodiment. Also,
3 is a schematic sectional view taken along the line BB of FIG. 2, and FIG. 4 is a cross section of FIG.
The outline of each -C cross section is shown.

As shown in these drawings, a cathode electrode 12A and an anode electrode 12B are provided on both surfaces of the electrolyte 11.
Are arranged to form a unit cell 13, and a cell structure is formed by laminating the electrolyte 11 at predetermined intervals in the plate thickness direction via a ceramic ring 21. Therefore, in the single cell 13, the anodes and the cathodes are laminated via the ceramic rings 21 at predetermined intervals so that the anodes and the cathodes are alternately arranged. The anode reaction passages 22B are alternately formed.

In the stacking direction of the unit cell 13, as shown in FIGS. 3 and 4, a fluid is applied to each of the cathode electrode 12A and the anode electrode 12B (in this embodiment, "steam (H ₂ O)" is used as the cathode side fluid. , A cathode fluid supply passage 23A for supplying / discharging “air (Air)” as an anode side fluid and a fluid discharge passage 24A, and an anode fluid supply passage 23B and a fluid discharge passage 24B are formed so as to penetrate therethrough. In addition, the cathode and anode fluid supply passages 23A and 23B and the fluid discharge passage 24 are provided.
A and 24B communicate with the cathode reaction passage 21A and the anode reaction passage 21B, respectively, such that the cathodes and the anodes communicate with each other.

FIG. 3 shows an outline of a state diagram in which the cathode electrodes 12A face each other to form a cathode reaction passage 22A, and the vertical passage on the right side of the drawing is a cathode fluid supply passage 23A. One of the passages in the vertical direction on the left side shows the discharge passage 24A, and each passage 23A,
24A communicates with the cathode reaction passage 22A through a communication hole 25A. On the other hand, in FIG. 4, an outline of a state diagram in which the anode electrodes 12B face each other to form an anode reaction passage 22B is shown, and the vertical passage on the left side of the drawing is the anode fluid supply passage 23B. The one vertical passage on the right side shows the discharge passage 24B, and each passage 23B, 24B communicates with the anode reaction passage 22B through a communication hole 25B.

As shown in FIG. 1, the electrolyte 11 of each of the stacked unit cells 13 is provided with a hole 26 serving as a current flow path, and the interconnector 27 and the cathode conductive material 2 are formed.
The anode electrode 12A and the cathode electrode 12B are electrically connected via a conductive member such as 8A, the anode conductive material 28B, and the bonding intermediate material 29.

In this embodiment, as shown in FIG.
In the plurality of stacked unit cells 13, the first layer unit cell 1
3-1 Anode electrode 12B provided on the electrolyte 11
Is electrically connected to the cathode electrode 12A of the second layer single cell 13-2, and the anode electrode 12B provided on the electrolyte 11 of the second single cell 13-2 is the third layer single cell 13A.
-2 cathode electrode 12A is electrically connected, and this connection is sequentially made. That is, the odd-numbered single cells 13-
1,13-3 ··· are defined as “A groups” and even-numbered single cells 1
When 3-2, 13-4 ... Are "B groups", the anode electrodes 12B of the unit cells of the A group are electrically connected to the cathode electrodes 12A of the group B adjacent in the cathode direction of the unit cells. . On the other hand, the cathode electrodes 12A of the A group are electrically connected to the anode electrodes 12B of the B group which are adjacent to each other in the anode direction of the unit cell. Although the stacking direction of the unit cells 13 is the vertical direction in the present embodiment, the present invention is not limited to this, and a plurality of cell structures are arranged in the direction orthogonal to the vertical direction. Can also be adapted.

Next, an example of a method of manufacturing the cell structure according to this embodiment will be described.

As shown in FIGS. 1 to 4, when laminated,
Fluid supply passages 23A, 24 and fluid discharge passages 23B, 2
4B and a flat plate-shaped electrolyte 11 each having a hole serving as a current flow path, and an interconnector 27 made of conductive ceramics, a bonding intermediate material 29 having insulating property or low conductivity is sandwiched. Then, temporarily fix both with an adhesive,
By applying a slurry made of an anode agent to be the anode electrode 12B to one surface of the electrolyte 11 which is one surface thereof, and then applying pressure in the thickness direction of the electrolyte at high temperature,
These parts are joined and fired.

Further, a cathode is applied and fired on the lower surface side of the electrolyte 11 obtained by firing the anode electrode 12B in the same manner by using a slurry made of a cathodic agent which becomes the cathode electrode 12A. -1 was constructed.

Next, contrary to the single cell 13-1 of the first layer,
A second-layer single cell 13-2 was formed by firing the cathode electrode 12A on the upper surface side of the electrolyte 11 and the anode electrode 12B on the lower surface side.

In this way, the odd-numbered unit cells 13-1, 13-3
... is the cathode electrode 12A on the upper surface side of the electrolyte, and one even-layer single cell 13-2, 13-4 is the anode electrode 12
Using B formed on the upper surface side of the electrolyte 11,
Using the ceramic ring 21, the electrolyte 11 was sequentially laminated in the plate thickness direction and temporarily fixed with an adhesive. At this time, the electrolytes are arranged such that the cathode surface and the cathode surface face each other and the anode surface and the anode surface face each other.

Further, as shown in FIG. 1, for example, the interconnectors 27 facing each other, which are joined to the electrolyte 11 of the unit cell 13-1 of the first layer and the electrolyte of the unit cell 13-2 of the second layer adjacent thereto, Between 27, the interconnector 2 of both
In order to electrically connect 7 and 27, the cathode side conductive agent 28A is sandwiched between the cathode side and the anode side conductive agent 28B is sandwiched between the anode side. Moreover, you may make it laminate | stack by combining what formed the electrolyte 13 into a unit.

By pressing the above-mentioned laminated body in the plate thickness direction of the electrolyte at a high temperature, these materials are bonded and fired to manufacture an electrolytic cell.

As a result, since the gas that is a fluid is separated by the electrolyte plate, no members such as a partition plate and a separator for separating the gas are required, and both surfaces of the gas flow path are used as reaction surfaces. Therefore, the output per unit area of the cell can be improved.

Further, by disposing an insulating joining intermediate material between the electrolyte and the interconnector, damage to the joining portion between the electrolyte and the interconnector due to deterioration of current flow during operation of the cell is prevented, and durability of the cell is improved. It is possible to improve the property.

[0031]

As described above with reference to the embodiments, since the gas separation is performed by the electrolyte plate, a plate for gas separation is not required and both surfaces of the gas flow passage are used as reaction surfaces. The output per unit area of the cell can be improved. Further, the manufacturing can be efficiently performed by a simple method.

Further, by disposing an insulating joining intermediate material between the electrolyte and the interconnector, damage to the joining portion between the electrolyte and the interconnector due to deterioration of current flow during cell operation is prevented, and durability of the cell is improved. It is possible to improve the property.

Further, the electrolysis cell according to the present invention can be used in a plate type high temperature steam electrolysis cell and a cell of a fuel cell to improve the efficiency of each.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a cell structure according to this example.

FIG. 2 is a perspective view from the upper surface of the cell body according to the present embodiment.

FIG. 3 is a schematic view of a BB cross section of FIG.

FIG. 4 is a schematic view of a CC cross section of FIG.

FIG. 5 is a schematic view of a conventional electrolytic cell structure.

FIG. 6 is a principle diagram of steam electrolysis.

FIG. 7 is a principle diagram of a fuel cell.

[Explanation of symbols]

 11 Electrolyte 12A Cathode Electrode 12B Anode Electrode 13 Single Cell 21 Ceramic Ring 22A Cathode Reaction Passage 22B Anode Reaction Passage 23A Cathode Fluid Supply Passage 23B Anode Fluid Supply Passage 24A Cathode Fluid Discharge Passage 24B Anode Fluid Discharge Passage 25A, 25B Communication hole 26 Hole 27 Interconnector 28A Cathode conductive material 28B Anode conductive material 29 Joining intermediate material

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshihito Souman 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (72) Masahiko Inoue, Kobe, Hyogo Prefecture Hyogo 1-1-1 Wadazaki-cho, Tokyo Mitsubishi Heavy Industries, Ltd. Kobe Shipyard

Claims (6)

[Claims] 1. A cell structure in which a cathode electrode and an anode electrode are provided on both surfaces of an electrolyte, and a cathode fluid and an anode fluid are supplied to these electrodes, respectively. In the cell structure, the cathode electrode and the anode are provided on both surfaces of the electrolyte. The electrodes are arranged to form a single cell, and the single cells are laminated at a predetermined interval so that the cathodes and the anodes are alternately arranged, and the cathode reaction passage and the anode are laminated. A reaction passage is formed, and in the stacking direction of the unit cell, a fluid supply passage and a fluid discharge passage for the cathode and the anode for supplying / discharging the fluid to / from the cathode electrode and the anode electrode are formed, respectively. In addition, the cathode and anode fluid supply passages and the fluid discharge passages are respectively connected to the cathode reaction passage and the anode reaction passage, respectively. The cathodes and the anodes are communicated with each other, and holes to be a current flow path are formed in each of the stacked electrolytes, and the electrolytes are electrically connected to the cathode electrode and the anode electrode through a conductive material. A cell structure characterized by that. 2. The cell structure according to claim 1, wherein the plurality of single cells to be stacked are stacked with a predetermined space therebetween through a ceramic ring so that cathodes and anodes face each other. Cell structure. 3. The cell structure according to claim 1 or 2, wherein the electrical connection is made through an interconnector and a conductive agent. 4. The cell structure according to any one of claims 1 to 3, wherein, in a plurality of stacked single cells, the anode electrode provided on the electrolyte of the first layer single cell is electrically connected to the cathode electrode of the second layer single cell. The cell structure characterized in that the anode electrode provided on the electrolyte of the second unit cell is electrically connected to the cathode electrode of the unit cell of the third layer, and the connection is sequentially made. 5. The cell structure according to any one of claims 1 to 4, which is used in a flat plate type high temperature steam electrolysis cell in which an electrolyte is YSZ (Yttria Stabilized Zirconia). 6. The cell structure according to any one of claims 1 to 4, wherein the electrolyte is a solid electrolyte and is used for a cell of a fuel cell.