JPH09147890A - Solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve power generation characteristics and life characteristics by effectively suppressing the invasion of the excessive portion of sealing mate rial intervening between the cell and the peripheral portion of a separator plate into the edge portions of an anode and a cathode. SOLUTION: Excessive sealing material leading recessed portions 50 which lead the excessive portions of the sealing material in a parting direction from the edge portions of a cathode 11 and an anode are provided in portions approaching the cathode 11 and the anode at a stacking time on the top and bottom faces of end portions 30. The excessive sealing material leading recessed portion 50 has a wedge shape in a plan view spreading in a parting direction from the cathode 11 or the anode, and a tilting tapered face is formed inside so that a space between the recessed portion 50 and an opposite solid electrolyte plate 10 may become wider as it goes outward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell, and more particularly to improvement of outer peripheral portions of upper and lower surfaces of a separator plate.

[0002]

2. Description of the Related Art A flat plate type solid oxide fuel cell is
A cell in which an anode is arranged on one side of the central portion of the solid electrolyte plate and a cathode is arranged on the other side thereof, and an anode gas (hydrogen-rich fuel gas) and a cathode gas (air, etc.) are disposed so as to face the anode and the cathode, respectively. And a separator plate in which each gas channel of the oxidizer gas (1) is formed, and a plurality of sheets are alternately laminated. And high temperature (about 8
By supplying the anode gas and the cathode gas to the anode and the cathode, respectively, at 00 ° to 1000 ° C., an electrochemical reaction is generated through the solid electrolyte plate to generate power.

In such a flat plate type fuel cell, as in the fuel cell described in Japanese Patent Application No. 7-37310, an anode gas and a cathode are provided near the end of the separator plate 302 shown in FIG. Anode gas supply / discharge holes 306, 307 and cathode gas supply / discharge holes 316, 317 for distributing gas to each separator plate 302 and collecting gas from each separator plate 302 are provided. The outer peripheral portion 303 of the upper and lower surfaces of the separator plate 302 (that is, the side portions of the upper and lower surfaces of the separator plate 302, the anode gas supply / discharge holes 306 and 307, and the cathode gas supply / discharge hole 3).
16 and 317) are sealing materials 320 (see FIG. 6)
Is applied to form a melt seal portion (the lower surface is not shown), and in this portion, the space between the opposing cells 301 is sealed so that the anode gas and the cathode gas are separated from each other by the cells 301 and the separator plate 302. Outer periphery 30
It is prevented from leaking to the outside of the fuel cell through the space between the three.

The assembly of such a fuel cell is
First, on the outer peripheral portion 303 of the upper and lower surfaces of the separator plate 302,
This is performed by stacking the cells 301 after applying a sealing material 320 such as glass, which exhibits softening properties at the operating temperature of the fuel cell, in the form of powder.

[0005]

By the way, when assembling the above fuel cell, if the amount of the sealing material 320 applied to the outer peripheral portions 303 of the upper and lower surfaces of the separator plate 302 is too small, the sealing is performed at the operating temperature of the fuel cell. Even if the material 320 is softened, the sealing material 320 does not reach all the corners of the cell 3 and
01 and the outer peripheral portion 303 of the separator plate 302, there is a portion that is not sufficiently sealed, so that there arises a problem that the airtightness is impaired at that portion.

[0006] Therefore, conventionally, when assembling such a fuel cell, the amount of the sealing material 320 applied to the outer peripheral portions 303 of the upper and lower surfaces of the separator plate 302 is set to be excessive so that the cells 301 and the separator plate are separated. Outer peripheral portion 3 of 302
During the period 03, the sealing material 320 is spread over the entire area. Therefore, during operation, as shown in FIG. 6, the surplus portions 320a and 320b of the sealing material 320 were in a state of protruding from between the cells 301 and the outer peripheral portion 303 of the separator plate 302.

Here, the cell 301 and the separator plate 302
The sealing material 320a that protrudes outward from between the outer peripheral portions 303 is not a big problem because it does not affect the power generation life of the fuel cell, but it does not become a big problem, that is, toward the center, that is, the cathode 311 or The sealing material 320b protruding in the direction close to the anode 312 is diffused into the anode gas or the cathode gas, or the cathode 311 is diffused.
It comes into contact with the anode 312 and the anode 312 and enters the edge portions of the cathode 311 and the anode 312.

Therefore, the cathode 311 and the anode 3 are provided in the portion where the sealing material 320b has entered.
12 causes a chemical reaction with the sealing material 320b, and the cathode 3
11 or the anode 312 is corroded to deteriorate the performance as an electrode, or in extreme cases, the diffusion of the anode gas or the cathode gas into the cell 301 is hindered, so that the power generation voltage of the cell 301 is lowered. There was a problem of doing.

In view of the above problems, the present invention effectively suppresses the surplus of the sealing material interposed between the cell and the outer peripheral portion of the separator plate from entering the edges of the anode and the cathode, and An object of the present invention is to provide a solid oxide fuel cell capable of improving power generation characteristics and life characteristics of the cell.

[0010]

In order to solve the above problems, in the invention according to claim 1, a cell in which an anode is arranged on one side of a central portion of a solid electrolyte plate and a cathode is arranged on the other side. And a plurality of anode gas channels are formed on the surface facing the anode, and a separator plate having a cathode gas channel formed on the surface facing the cathode is alternately laminated. An anode gas supply / exhaust hole and a cathode gas supply / exhaust hole for distributing the anode gas and the cathode gas to each separator plate or collecting from the separator plate, respectively, and side and upper surfaces of the separator plate and the The peripheral parts of the anode gas supply / discharge hole and the cathode gas supply / discharge hole are
In a solid oxide fuel cell, which is a melt seal part in which a sealing material is arranged, and a space between the opposing solid electrolyte plates is sealed in the melt seal part, the anode is provided on the upper surface and the lower surface of the melt seal part. Alternatively, the present invention is characterized in that a guide portion for guiding an excessive amount of the sealing material close to the cathode in a direction away from the anode or the cathode is formed.

Therefore, the upper and lower surfaces of the melt seal portion of the separator plate are formed so as to guide the excess sealing material in the vicinity of the anode or cathode in the direction away from the anode or cathode. It is possible to effectively prevent the surplus portion from entering the edges of the anode and cathode, prevent corrosion of the anode and cathode, etc., and prevent deterioration of the power generation characteristics, life characteristics, etc. of the fuel cell. .

According to a second aspect of the present invention, the upper surface and the lower surface of the melt-sealed portion are continuously spaced apart from the solid electrolyte plate facing each other as the distance from the anode or the cathode increases, in a range close to the anode or the cathode. It is characterized in that a sealing material guiding portion having a tapered surface that widens inside is provided.

Here, the larger the stacking interval between the solid electrolyte plate and the separator plate facing each other, the smaller the dynamic resistance received by the sealing material moving between them. Therefore, according to the second aspect of the present invention, when the fuel cell is in operation, the surplus of the sealing material has a large stacking interval between the opposing solid electrolyte plates on the upper and lower surfaces of the melt seal portion of the separator plate. Direction is effectively guided in the direction away from the anode or the cathode, so that the excess sealing material is prevented from entering the edges of the anode or the cathode.

According to a third aspect of the present invention, the melt-sealing portion is such that the sealing material guiding portion communicates with the outer peripheral portion of the separator plate and the inner wall of the anode gas supply / discharge hole or the cathode gas supply / discharge hole. It is characterized in that it is a concave portion formed on the upper surface and the lower surface. Therefore,
When the fuel cell is in operation, the excess sealing material passes through the recesses and efficiently protrudes outside the separator plate or inside the anode gas supply / discharge holes and the cathode gas supply / discharge holes. Even in many cases, they can be suppressed from penetrating into the edges of the anode and the cathode.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a solid oxide fuel cell according to the present invention will be specifically described below with reference to the drawings. (Embodiment 1) FIG. 1 is an exploded perspective view of a solid oxide fuel cell in this embodiment. For the sake of explanation, in FIG. 1, the front direction of the drawing is the front of the fuel cell, and the back direction of the drawing is the rear of the fuel cell.

The solid oxide fuel cell is a flat plate type fuel cell, and as shown in FIG. 1, a predetermined number of cells 1 and separator plates 2 are alternately laminated, and both ends thereof are a pair of end plates (not shown). It is held down by. The number of stacked cells 1 and separator plates 2 is normally set to several tens to several hundreds based on the size of the unit cell voltage of the fuel cell and the required external output. In FIG. 1, one cell 1 and one separator plate 2 are shown for convenience of illustration.

In the cell 1, the cathode 11 is arranged at the center of the upper surface of the solid electrolyte plate 10, and the anode 1 is arranged at the center of the lower surface.
2 (not shown in FIG. 1 because it is located on the opposite side of the cathode 11). Then, for example, the solid electrolyte plate 10 is composed of a plate having a size of about 150 mm × 150 mm, which is made of a dense fired body of partially stabilized zirconia containing 3 mol% yttria, and the cathode 11 is a perovskite of La _0.9 Sr _0.1 MnO ₃ . Type oxide, the anode 12 is Ni-Z
Each is composed of rO ₂ cermet.

Anode gas supply / exhaust hole openings 13 and 14 (provided that the anode gas is distributed to or recovered from each separator plate 2 are provided at both the front center and the rear left and right parts of the solid electrolyte plate 10. The anode gas supply / exhaust holes on the left rear side are hidden behind the separator plate 2 and are not shown in the figure.) Are provided respectively, and cathode gas is provided on each of the rear center portion and the front left and right portions. Cathode gas supply / discharge holes 15, 16 and 17 for distributing or recovering from each separator plate 2 are provided in the plate 2, respectively.

The separator plate 2 is a plate having the same size as the solid electrolyte plate 10 and made of, for example, a Ni--Cr heat resistant alloy, and has a central portion (ie, anode) on the upper and lower surfaces thereof. 12 and the portion facing the cathode 11), each having a plurality of anode gas channels 2
2 and a cathode gas channel (not shown because they are located on the back side of the separator plate 2) are formed, and are connected to the anode gas channel 22 and the cathode gas channel near each end. An anode side internal manifold 22a and a cathode side internal manifold (not shown) are provided. Further, anode gas supply / discharge holes 23, 24, 25 for distributing anode gas to each separator plate 2 or recovering each anode plate from each separator plate 2 are respectively provided in the front center part and the rear left and right parts, and the rear center part is formed. And cathode gas supply / exhaust holes 26, 27, 28 for distributing the cathode gas to each separator plate 2 or collecting from each separator plate 2 in the front left and right parts.
Has been established respectively.

It should be noted that the anode formed on the solid electrolyte plate 10 is
, And cathode gas supply / discharge holes 15,
... and the anode gas supply / discharge holes formed in the separator plate 2
23, ... and cathode gas supply / discharge holes 26 ,.
Correspond to each other so that they each overlap exactly
The position, shape and size are set. Also,
The peripheral portions 30 (that is, the separation
Side portions of the upper and lower surfaces of the anode plate 2, the anode gas supply / discharge holes 23, ...
And the peripheral portions of the cathode gas supply / discharge holes 26, ...
Silicate glass (81SiO_Two-13B_TwoO_Three-2Al
_TwoO _Three-3Na_TwoO-1K_TwoO (wt%)) as a material
Sealing material 40 (however, not shown in FIG. 1)
No. ) Is arranged in the melt seal part.
The part is sealed between the opposing solid electrolyte plates 10.
It has become so.

By the way, on the upper and lower surfaces of the above-mentioned peripheral portion 30,
As shown in FIG. 1, a plurality of excessive sealing material guiding recesses 50 are formed by cutting, polishing, or the like in a portion close to the anode 12 and the cathode 11 during stacking. Here, FIG. 2 is a schematic view in which a part of the cross section taken along the line XX of FIG. 1 is enlarged, and the part of the recess 50 for guiding the excess sealing material is cut.

The recess 50 for guiding the excess sealing material is wedge-shaped in a plan view and spreads away from the cathode 11 or the anode 12, and one end near the center thereof is
The other end, which is located in the vicinity of the anode 12 and the cathode 11 and is located on the outer side, is open to the outer wall of the peripheral portion 30 or the inner walls of the anode gas supply / discharge holes 23, ... And the cathode gas supply / discharge holes 26 ,.

In addition, as shown in FIG. 2, inside the recess 50 for guiding the excess sealing material, the stacking interval with the facing solid electrolyte plate 10 is inclined so that it becomes larger as the distance from the cathode 11 or the anode 12 increases. Tapered surface 5
1 is formed, and the depth is 0 at one end near the center and about 100 to 200 μm at the other end near the outside.

The surplus amount of the sealing material 40 arranged in the recess 50 for guiding the excessive sealing material is generated during the operation of the fuel cell.
Outside the peripheral portion 30, or the anode gas supply / discharge holes 23, ...
And the cathode gas supply / discharge holes 26, ... This is because when the surplus of the sealing material 40 protrudes between the upper and lower surfaces of the peripheral portion 30 and the solid electrolyte plate 10 facing the peripheral portion 30, the upper and lower surfaces of the peripheral portion 30 and the solid electrolyte plate 1 are covered.
The direction in which the dynamic resistance due to the frictional force from 0 becomes smaller,
That is, the reason is that the upper and lower surfaces of the peripheral portion 30 and the solid electrolyte plate 10 facing the peripheral portion 30 are likely to protrude in a direction in which the distance becomes wider. In addition, this means that the excess sealing material guiding recess 50
However, it also contributes to the fact that it is a wedge type that spreads away from the cathode 11 or the anode 12.

Regarding the formation position, the number, the size, etc. of the above-mentioned excess sealing material guiding recesses 50, the operating temperature of the fuel cell, the material of the separator plate 2 and the sealing material 40, the peripheral portion 3
Based on the size of 0, the excess amount of the sealing material 40 is prevented from entering the edges of the cathode 11 and the anode 12, and the space between the solid electrolyte plate 10 and the peripheral portion 30 of the separator plate 2 is effectively sealed. Is set to.

In order to confirm this, a comparative example having the same structure as that of the solid oxide fuel cell of the present embodiment, except that the peripheral sealing portion 30 of the separator plate 2 is not provided with the excessive sealing material guiding recess 50. The solid electrolyte fuel cell of No. 1 was used to measure the degree of penetration of the sealing material 40 at the edge of the cathode 11 or the anode 12. In addition, the measurement is performed after the operation of the fuel cell is completed by detecting the Si component, which is the main component of the sealing material 40, at the edge of the cathode 11 or the anode 12, and how much the Si component is from the edge of the cathode 11 or the anode 12. The width is compared whether it exists inside.

As a result, in the fuel cell of this embodiment, 1 m
The Si component was detected only in a width of about m, but in the fuel cell of the comparative example, the Si component was detected in a width of about 5 mm, confirming the effect of this example. It should be noted that the above-mentioned recessed portion 50 for guiding the excess sealing material does not necessarily have to be wedge-shaped, and the same effect can be obtained even if it has a U-shaped shape, for example. Further, in this embodiment, the position where the recessed portion 50 for guiding the excess sealing material is formed is the portion of the peripheral portion 30 which is close to the anode 12 and the cathode 11, but the position is not limited to this, and the peripheral portion 30 may be formed. It may be formed anywhere on the surface.

For example, when the surplus sealing material guiding recess 50 is similarly formed in the edge portions 31 on the upper and lower surfaces of the separator plate 2, the surplus portion of the sealing material 40 is the anode gas supply / discharge holes 23 ,. Since it is possible to suppress the protrusion of the cathode gas supply / discharge hole 26, ...
, And the inner walls of the cathode gas supply / discharge holes 26, ... Can be made into a more balanced flat surface, and it is possible to suppress the turbulent flow of the anode gas and the cathode gas flowing through the inside, which is more preferable. .

(Embodiment 2) The solid oxide fuel cell of this embodiment is similar to the solid electrolyte fuel cell of Embodiment 1 except that the separator plate 2 shown in FIG.
The separator plate 102 as shown in FIG. 4 is used, and the other configurations are the same as those in the first embodiment. The separator plate 102 and the separator plate 2 in the first embodiment are different only in the configuration of the peripheral portion 130.

A peripheral portion 130 on the upper and lower surfaces of the separator plate 102.
Is provided with a recessed portion 150 for guiding the excess sealing material, which has a tapered surface 151 inclined so that the distance from the solid electrolyte plate increases as the distance from the anode and the cathode increases, over the entire portion in the vicinity of the anode and the cathode. There is. In such a fuel cell, the surplus of the sealing material is evenly and effectively protruded outward in the region where the recess 150 for guiding the surplus sealing material is provided. Penetration into the edges of the anode and the cathode can be suppressed more effectively.

(Modification) In the solid oxide fuel cell of Example 1, a separator plate 202 as shown in FIG. 4 can be used instead of the separator plate 2. The separator plate 202 is different from the separator plate 2 only in the configuration of the peripheral portion 230.

A peripheral portion 230 on the upper and lower surfaces of the separator plate 202
Is provided with a plurality of oval recesses 250 deeply formed so as to take in a surplus of the sealing material in a portion close to the anode and the cathode. Even in such a fuel cell, the excess amount of the sealing material is introduced into the recess 250 to some extent, so that the sealing material is prevented from entering the anode and cathode edges. Further, in this case, the amount of protrusion of the separator plate 202 to the outside can be reduced to some extent.

The formation position, shape, and
The number, size, etc. are set in the same manner as in the case of the above-mentioned recesses 50 for guiding the excess seal material. In the above-described Example 1 (or Example 2, reference example), the peripheral portion 3
Although 0 (or 130, 230) is formed integrally with the separator plate 2 (or 102, 202), the peripheral portion 30 (or 130, 230) and the separator plate 2 (or 102, 202) are The present invention can also be applied to those formed separately.

[0034]

As described above, in the present invention, the excess amount of the sealing material is guided in the direction away from the anode and the cathode, and the corrosion of the anode and the cathode due to the penetration of the sealing material into the edges of the anode and the cathode. It is possible to prevent the deterioration of power generation characteristics, life characteristics and the like. Therefore, the reliability of the solid oxide fuel cell can be improved and the practical value is great.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a solid oxide fuel cell according to a first embodiment.

FIG. 2 is a partially enlarged view of a section taken along line XX of FIG.

FIG. 3 is a perspective view of a separator plate according to a second embodiment.

FIG. 4 is a perspective view of a separator plate according to a modified example of the present invention.

FIG. 5 is an exploded perspective view of a solid oxide fuel cell according to a conventional example.

6 is a partial enlarged view of a cross section taken along the line AA of FIG.

[Explanation of symbols]

 1 Cell 2, 102, 202 Separator Plate 10 Solid Electrolyte Plate 11 Cathode 12 Anode 22 Anode Gas Channel 23-25 Anode Gas Supply / Discharge Hole 26-28 Cathode Gas Supply / Discharge Hole 30, 130, 230 Circumference 40 Sealing Material 50, 150 Excessive sealing material guiding recess 250 recess

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shoten Kadowaki 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Inventor Yasuo Miyake 2-chome, Keihan Hondori, Moriguchi City, Osaka Prefecture No. 5-5 Sanyo Electric Co., Ltd.

Claims (3)

[Claims] 1. A cell in which an anode is arranged on one side of a central portion of a solid electrolyte plate and a cathode is arranged on the other side of the solid electrolyte plate, and a plurality of anode gas channels are formed on a surface facing the anode. And a separator plate having a cathode gas channel formed on the surface facing each other are alternately laminated, and the anode gas and the cathode gas are distributed to each separator plate or collected from each separator plate near the end of the separator plate. An anode gas supply / discharge hole and a cathode gas supply / discharge hole are opened respectively, and a sealing material is arranged on the upper and lower sides of the separator plate and the peripheral portions of the anode gas supply / discharge hole and the cathode gas supply / discharge hole. In the solid electrolyte fuel cell, which is a melt-sealed portion that is sealed, and is sealed between the opposing solid electrolyte plates at that portion, A solid electrolyte type, characterized in that, on the upper surface and the lower surface of the melt seal portion, an induction portion for inducing a surplus of the sealing material adjacent to the anode or the cathode in a direction away from the anode or the cathode is formed. Fuel cell. 2. The upper surface and the lower surface of the melt-sealed portion are tapered surfaces in which a space between the facing solid electrolyte plate and the facing solid electrolyte plate is continuously widened as the distance from the anode or the cathode is increased. 2. The solid oxide fuel cell according to claim 1, further comprising a sealing material guide portion having the inside thereof formed therein. 3. The seal material guide portion is formed on the upper surface and the lower surface of the melt seal portion so as to communicate with the outer peripheral portion of the separator plate and the inner wall of the anode gas supply / discharge hole or the cathode gas supply / discharge hole. The solid oxide fuel cell according to claim 2, wherein the solid electrolyte fuel cell is a concave portion.