JPH1197042A - Layered fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve the gas sealability of a seal part such as a wet seal part or a manifold seal part, and to precisely keep the cell performance. SOLUTION: This layered fuel cell comprises an edge spring 31 interposed between the inner peripheral edge 7b and an interconnector 6 for closely bringing an anode edge plate 7 into contact with an electrolyte matrix 2 by pressing an inner peripheral edge part 7b of the anode edge plate 7 to a peripheral edge part 2a of the electrolyte matrix 2 by the elastic force, and a seal reinforcement plate 35 having a projecting part 35a on an area opposing to the inner peripheral edge part 7b, along a peripheral edge direction thereof, is interposed between the edge spring 31 and the inner peripheral edge 7b of the anode edge plate 7, for reinforcing the adhesive force between the anode edge plate 7 and the electrolyte matrix 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit cell having a fuel electrode (anode) and an air electrode (cathode) opposed to the anode with an electrolyte matrix interposed therebetween, a fuel gas at the anode and an oxidant at the cathode. The present invention relates to a stacked fuel cell configured by alternately stacking separators for guiding gas with a space therebetween, and more particularly to a stacked fuel cell having improved gas sealing properties using an elastic member such as a spring.

[0002]

2. Description of the Related Art A fuel cell is a power generation system in which hydrogen ions generated at a fuel electrode (anode) electrochemically react with oxygen ions on an air electrode (cathode) via an electrolyte matrix to directly generate electric energy. In general, a large-capacity stacked fuel cell is formed by stacking a plurality of unit cells each having the above-described anode, electrolyte matrix, and cathode.

[0003] A fuel gas such as hydrogen gas for generating hydrogen ions is continuously supplied between the cells of the stacked fuel cell, and an oxidizing gas such as air for generating oxygen ions is provided on the cathode. And a function of continuously supplying the cells and a function of electrically connecting the respective cells in series. In order to prevent the fuel gas and the oxidizing gas from being mixed with each other at the time of gas supply and to prevent the power generation performance from deteriorating, the separator is separated from the fuel gas flow path through which only the fuel gas flows and the fuel gas flow path. And an oxidizing gas flow path through which only the oxidizing gas flows.

[0004] Among the stacked fuel cells having the separator described above, FIG. 6 shows a molten carbonate fuel cell using an electrolyte matrix formed by molten carbonate, in particular. FIG. 6 shows only a single cell portion of the fuel cell, which is composed of a single cell and a separator laminated on the single cell. FIG. 7 shows a cross-sectional view taken along the line CC in FIG. 6 (this cross-sectional view shows a state in which two single cells are stacked).

The unit cell 1 is composed of a rectangular plate-shaped electrolyte matrix 2 and a rectangular plate-shaped anode 3 and cathode 4 which are arranged in close contact with both sides (upper and lower surfaces on the lamination side).

[0006] The electrolyte matrix 2 is formed by filling the gaps between porous bodies composed of metal oxide particles with carbonates. The carbonates are solid at room temperature, but at a power generation operating temperature. It becomes a molten state. Further, the electrolyte matrix 2 is formed to be slightly larger than the anode 3 and the cathode 4. Anode 3 and cathode 4
Is a porous body of a metal or a metal oxide, and the carbonate is also partially filled in the pore gap between the anode 3 and the cathode 4. The size of the anode 3 and the size of the cathode 4 are different from each other in order to prevent a shearing force from acting at the boundary between the anode 3 and the cathode 4 (electrode) and an adjacent separator (edge plate described later). Have been.

A fuel cell constituted by stacking the above-mentioned unit cells 1 is operated at a temperature of about 650 ° C. During the operation, the anode 3 and the cathode 4 of each unit cell 1 are operated.
Are supplied with a fuel gas and an oxidizing gas, respectively. The fuel gas and the oxidizing gas are electrochemically reacted at the interface between the molten carbonate and the anode 3 and the cathode 4 to generate electric energy.

On the other hand, on the upper and lower sides of the cell 1,
The separator 5 is arranged in close contact (in FIG. 6, only a part of the separator 5 is shown on the upper surface side of the unit cell 1). The separator 5 is basically formed by laminating a plate-shaped gas-impermeable interconnector 6, an anode edge plate 7, a cathode edge plate 8, an anode current collector 9, and a cathode current collector 10. The fuel gas 11 is introduced to the anode 3 and the oxidant gas 12 is introduced to the cathode 4 without being mixed.

The anode edge plate 7 and the cathode edge plate 8 are formed in a rectangular thin plate shape having a substantially uniform thickness, and a rectangular opening plate having a central portion cut out in a rectangular shape for disposing the anode 3 and the cathode 4. Is configured as The outer peripheral edges 7a, 8a of the both edge plates 7, 8 are connected to the outer peripheral edge 6a of the interconnector 6.
a is sandwiched from the anode side and the cathode side so as to sandwich “a”. In addition, edges (inner peripheral edges) 7b, 8b around the rectangular opening H in the anode edge plate 7 and the cathode edge plate 8 project in a convex shape toward the anode side and the cathode side, respectively. The plate 7 and the cathode edge plate 8 have outer peripheral edges 7a, 8a
And an inner peripheral edge portion 7b, 8b. Then, (the electrolyte matrix 2 of) the unit cell 1 in which the inner peripheral edges 7b, 8b of the edge plates 7, 8 face the inner peripheral edges.
Is closely contacted with the peripheral edge portion 2a.

Since the anode edge plate 7 and the cathode edge plate 8 are formed of thin plates as described above, the inner peripheral edges 7b and 8b are bent toward the anode side and the cathode side. It is possible to absorb a dimensional deviation and the like in the laminating direction (thickness direction) of each component of the separator.

Anode current collector 9 and cathode current collector 10
Are unevenly planarized at substantially constant intervals by, for example, alternately bending stainless steel rectangular flat plates. The anode current collector plate 9 is arranged so as to be surrounded by the anode edge plate 7, and the convex portion of the concave and convex surface on the anode side is joined to the anode 3, and the convex portion of the concave and convex surface on the interconnector 6 side is joined to the interconnector 6. ing. Similarly, the cathode current collector plate 10 is also arranged so as to be surrounded by the cathode edge plate 8, and the convex portion of the concave and convex surface on the cathode side corresponds to the cathode 4, and the convex portion of the concave and convex surface on the interconnector 6 corresponds to the interconnector 6. Each is joined. The current collectors 9 and 10 thus configured are in close contact with the electrodes 3 and 4 to support the surfaces of both electrodes and collect electricity generated on the unit cell 1 uniformly in the surface. The gas flow path is secured by the space formed by the projections of the uneven surface. These current collectors have two parts: a part that supports and collects the electrode surface (called a current collector) and a part that supports the current collector and secures a gas flow path (called a current collector support). It may consist of two independent components.

As shown in FIG. 7, between the anode edge plate 7 and the cathode edge plate 8 and the interconnector 6, there are provided an anode edge spring 13 and a cathode edge spring 14 which can expand and contract in the cell stacking direction. The inner edge portions 7b and 8b of the anode edge plate 7 and the cathode edge plate 8 are pressed against the peripheral edge portion 2a of the electrolyte matrix 2 by the action of the anode edge spring 13 and the cathode edge spring 14, respectively. The edge plate 7 and the cathode edge plate 8 are securely adhered to the electrolyte matrix 2. As a result, the molten carbonate of the electrolyte matrix 2 wets (wet seals) the interface between the both edge plates 7 and 8 and the electrolyte matrix 2, so that the fuel gas and the oxidizing gas are supplied to the both edge plates 7 and 8 and Leakage from between the electrolyte matrices 2 is prevented (Japanese Patent Laid-Open No. 6-290797).
Reference).

FIG. 8 shows an example of the above-described edge spring (for example, the anode edge spring 13). According to FIG. 8, the edge spring 13 is connected to the electrolyte matrix 2.
An inner edge portion 7b opposed to the edge portion 2a is interposed between the anode edge plate 7 and the interconnector 6, which are in close contact with one edge portion 2a of the four edge portions. It has a structure in which a plurality of spring plates 20 having a spring structure are stacked (FIG. 8 shows a four-stage structure).

That is, each of the spring plates 20 of the edge spring 13 extends along the peripheral direction of the inner peripheral edge 7b of the anode edge plate 7 (the electrolyte matrix peripheral edge 2a in contact with the inner peripheral edge 7b) over one surface of the thin plate. (Peripheral direction of the inner peripheral edge 7b) are provided along the direction perpendicular to the inner peripheral edge 7b.

The projecting portion 20a of each spring plate 20 is formed by projecting a corresponding portion of the thin plate toward the inner peripheral edge 7b of the anode edge plate 7 in a convex shape. The direction is orthogonal to the peripheral direction of the peripheral portion 7b. One of the spring plates 20 adjacent in the laminating direction has its protruding portion 20a.
Are stacked so as to be shifted by a half pitch from the other adjacent protruding portion 20a.

In FIG. 8, one of the four peripheral edges 2a of the electrolyte matrix 2 and the peripheral edge 2a
Although only the edge spring 13 provided along is shown, the anode edge spring 13 having the above-described structure is
Interposed between the anode edge plate 7 and the interconnector 6 along the four edges of the unit cell 2. The cathode edge spring 14 has the same structure.

Further, a gas supply / discharge manifold is provided in a cell reaction portion of the stacked fuel cell. FIGS. 6 and 7 show an internal manifold type fuel cell in which a manifold is provided inside the separator 5. Each separator 5 (anode edge plate 7 and cathode edge plate 8) has the separator 5 (anode edge plate 7). A through-hole (manifold hole) 25 penetrating through the edge plate 7 and the cathode edge plate 8) in the stacking direction is provided, and the two through-holes 25 facing the unit cell 1 in an airtight state via a manifold ring 26. The fuel cells 11 and the oxidizing gas 12 supplied from outside are connected to each other along a flow path formed by the edge plates 7 and 8 and the interconnector 6 through the manifold ring 26 and the through hole 25. 1 (see the arrow in FIG. 6), and the fuel gas and the oxidizing gas discharged from the cell 1 are supplied to the through hole 25 and the manifold ring 26. It is adapted to discharge to the outside through.

Incidentally, one of the structures of the manifold ring portion including the manifold ring is such that one of the anode-side and cathode-side end faces of the manifold ring is joined to an adjacent anode edge plate or cathode edge plate, and the other is formed. By merely mechanically (non-adhered) contacting the end face to the adjacent cathode edge plate or anode edge plate with an electrically insulating sealing material interposed therebetween,
There is known a configuration in which the sealing property between the sealing material of the manifold portion and the edge plate is improved without causing the deterioration of the sealing property due to the peeling of the adhesive, and the leakage of the fuel gas and the oxidizing gas is prevented.

In the above-described configuration in which the manifold ring is brought into mechanical contact with the edge plate, it is desirable that the manifold ring be contracted in accordance with the contraction force of the edge spring, and a structure having a spring function like the edge spring is employed. You can also. JP-A-07-
In 2013353, like the edge spring,
A manifold portion including a manifold ring is formed by using a spring member formed by stacking a plurality of spring plates having projecting portions of equal pitch along the inner peripheral edge of the through hole.

As described above, a molten carbonate fuel cell having a laminated structure is formed by laminating a separator and a unit cell. Particularly, at the interface between the edge plate and the unit cell (electrolyte matrix), only the contact is made. The fuel cell and the oxidizing gas inside and outside the single cell are sealed by the fuel cell, so that the fuel cell is tightened from above and below in order to improve the contact state.

[0021]

In the fuel cell having the above-described stacked structure having the edge springs, the edge springs 13 and 14 are interposed along the four peripheral edges 2a of the unit cell 2, respectively. That is, the edge springs 13 (14) are connected to the unit cells 1 parallel to the flow directions (see arrows) of the fuel gas 11 and the oxidizing gas 12 shown in FIG.
From the region along the peripheral portion 2a of the (electrolyte matrix 2) and the region along the peripheral portion 2a of the unit cell 1 perpendicular to the flow direction of the fuel gas 11 and the oxidizing gas 12, that is, from the manifold (through hole 25). It is also provided on a flow path formed by the edge plates 7 and 8 up to the cell 1 and the interconnector 6. Therefore, in the conventional configuration, as shown in FIG. 8, the bending line of each protrusion 20a is set in a direction perpendicular to the peripheral direction of the inner peripheral edge 7b (8b) of the edge plate 7 (8), In the edge spring 13 (14) provided on the flow path, the edge spring 1
The gas smoothly flows through the space (flow path) formed by the protrusion 20a and the roots 20b, 20b of the third (14).

However, since the protruding portions 20a are provided discontinuously (non-uniformly) at predetermined pitches p along the peripheral edge of the unit cell 1, the thin plate-like shape is formed with the contraction of the edge springs 13 (14). A discontinuous pressure acts on the edge plates 7 and 8. As a result, in the central portion M of the inner peripheral edge portion 7b of the edge plate (for example, the anode edge plate 7) in contact with each of the protrusions 20a of the spring plate 20, the central portion M and the peripheral edge portion 2a of the electrolyte matrix 2 are securely connected. There is a danger that the contact surface pressure required to adhere to the surface cannot be obtained, and there is a danger that the gas sealing performance is impaired (the same applies to the cathode edge plate 8).

Similarly, since the projecting portions of the spring plate are arranged on the inner peripheral edge of the through hole at a predetermined pitch along the peripheral direction of the manifold portion having the spring function, the same applies to the manifold ring. Contact pressure is not obtained at the contact surface between the sealing material
There has been a risk that the sealing performance between the manifold and the separator may be impaired.

As described above, the contact surface pressure is insufficient at the seal portion between the cell and the separator (edge plate) (wet seal portion) and between the manifold portion and the separator (edge plate) (manifold seal portion). If the sealing property is deteriorated, leakage of the fuel gas and the oxidizing gas, inflow of the battery atmosphere gas, mixing of the fuel gas and the oxidizing gas, and the like may occur, thereby deteriorating the performance of the battery and reducing the reliability of the fuel cell. Had occurred.

The present invention has been made in view of the above-mentioned circumstances, and further enhances gas sealing properties of seal portions such as a wet seal portion and a manifold seal portion to maintain a high level of cell performance and improve the reliability of a fuel cell. It is an object of the present invention to provide a stacked fuel cell having improved characteristics.

[0026]

In order to achieve the above object, according to the present invention, a portion of an edge plate which is in contact with a unit cell (electrolyte matrix) is opposed to an inner peripheral edge portion of the edge plate. In some cases, for example, the case may be indirectly opposed via a cover or the like), and a reinforcing plate provided with a protruding portion along the circumferential direction is interposed, so that a peripheral edge of the inner peripheral edge portion is provided. A continuous and uniform contact surface pressure acts in the direction (peripheral direction of the unit cell), whereby the adhesion between the unit cell and the edge plate is strengthened, and the sealing property can be improved.

Further, according to the present invention, since the reinforcing ring provided with a protruding portion along the circumferential direction of the insulating ring is provided at a portion facing the insulating ring in contact with the separator, the reinforcing ring is provided in the circumferential direction of the insulating ring. A continuous and uniform contact surface pressure acts along the gap, whereby the adhesion between the separator and the insulating ring is strengthened, and the sealing performance can be improved.

That is, according to the stacked fuel cell of the present invention, a plurality of single cells each having an electrolyte matrix sandwiched between an anode and a cathode are stacked, a fuel gas is supplied to the anode, and a fuel gas is supplied to the cathode. A stacked fuel cell in which a separator for introducing an oxidant gas is interposed between adjacent unit cells, wherein the separator separates a flow path of the fuel gas and a flow path of the oxidant gas. An interconnector for forming the interconnector, and two edge plates having openings at the central portions respectively disposed on the anode adjacent side and the cathode adjacent side of the interconnector surface so as to sandwich the peripheral edge of the interconnector. The inner peripheral edge of the periphery of the opening of each edge plate is configured to be in contact with the peripheral edge of the electrolyte matrix, and the front edge is located between the edge plate and the interconnector. A fuel gas flow path and an oxidizing gas flow path are formed, the interconnector and the anode central part and the interconnector and the cathode central part are interposed respectively to support the anode and the cathode, and the fuel gas flow path and In a stacked fuel cell having a current collector for securing an oxidant gas flow path, the inner peripheral edge is interposed between the inner peripheral edge of each edge plate and the interconnector and elastically deforms the inner peripheral edge. An edge spring that is pressed against the periphery of the electrolyte matrix to make the edge plate and the electrolyte matrix adhere to each other, and in order to reinforce the adhesion between the edge plate and the electrolyte matrix, the inside of the edge spring and each of the edge plates is used. A reinforcing member provided with a protruding portion along the peripheral direction at a portion facing the inner peripheral portion between the peripheral portion and the peripheral edge; To have.

[0029] According to the stacked fuel cell described in claim 2, the protruding portion is provided toward the inner peripheral edge of the edge plate.

According to the third aspect of the present invention, the edge spring is provided at a portion facing the inner peripheral edge of the edge plate along a direction perpendicular to the peripheral direction of the inner peripheral edge. It is formed by laminating a plurality of spring plates having a plurality of protrusions arranged at a predetermined pitch in the peripheral direction, and the protrusions of the spring plate adjacent in the stacking direction are shifted by half a pitch from the other protrusion adjacent to the spring plate. It is configured.

According to the stacked fuel cell described in claim 4, the reinforcing member is configured as an opening plate having an opening having substantially the same size as the opening of the edge plate,
The protruding portion is provided continuously over the entire periphery of the electrolyte matrix at a portion of the opening plate facing the inner periphery of the edge plate.

On the other hand, in order to achieve the above object, according to the stacked fuel cell according to the fifth aspect, a plurality of single cells each having an electrolyte matrix sandwiched between an anode and a cathode are stacked and a plurality of cells are stacked on the anode. In a stacked fuel cell comprising a fuel gas and a separator for introducing an oxidant gas to the cathode with a separator interposed between each unit cell, the separator is used for independently introducing the fuel gas and the oxidant gas. And a plurality of holes that penetrate the separator in the stacking direction, and a manifold portion that is interposed between the through holes of adjacent separators via the unit cells and that allows the through holes to communicate with each other in an airtight manner. The part is a ring-shaped manifold spring that can be contracted in the laminating direction, and at least one of the manifold spring and the adjacent separator. Also a interposed by the insulating ring electrically insulating, which is adhered to the separator between one,
The manifold spring includes a reinforcing ring provided with a protruding portion along a circumferential direction of the insulating ring at a portion facing the insulating ring in order to reinforce the adhesion between the insulating ring and the separator. I have.

[0033] According to the stacked fuel cell described in claim 6, the protruding portion is provided toward the inner peripheral edge of the insulating ring.

According to the stacked fuel cell described in claim 7, the manifold spring is provided along the circumferential direction of the reinforcing ring at a portion facing the reinforcing ring and the seal reinforcing ring. A plurality of ring-shaped spring plates having a plurality of protrusions arranged at a predetermined pitch are stacked such that one of the adjacent ring-shaped spring plates is shifted by a half pitch from the other adjacent protrusion. And a laminate formed by covering the laminate with a spring cover.

According to the stacked fuel cell described in claim 8, the protrusion of the reinforcing ring is provided continuously over the entire circumference of the insulating ring.

According to a ninth aspect of the present invention, the stacked fuel cell is a molten carbonate type fuel cell using an electrolyte matrix formed by molten carbonate as the electrolyte matrix.

[0037]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is an enlarged view showing a part of an anode edge spring portion in a stacked fuel cell according to the present embodiment, and FIG.
It is sectional drawing in the -A arrow direction. Note that the stacked fuel cell of this embodiment is different from the stacked fuel cell shown in FIGS. 6 to 8 only in the edge spring portion. The same reference numerals are given and the description is omitted.

According to FIG. 1, the stacked fuel cell 30 has an inner peripheral edge formed on one of the four peripheral edges 2a of the cell 1 (electrolyte matrix 2) as in FIG. 7
b has an edge spring 31 interposed between the anode edge plate 7 and the interconnector 6 to each other. The edge spring 31 has a structure in which spring plates 32 having a leaf spring structure are stacked in multiple stages.
FIG. 1 shows a three-stage structure).

The protruding portion 32a of each spring plate 32 is formed to be bent in a convex shape so that the corresponding portion of the thin plate is directed toward the inner peripheral edge 7b of the anode edge plate 7 which is in close contact with the electrolyte matrix 2, The bending line is a direction orthogonal to the longitudinal direction of the inner peripheral edge 7b. One of the spring plates 32 adjacent in the stacking direction is stacked such that the protruding portion 32a is shifted by half a pitch from the other adjacent protruding portion 32a.

The anode edge spring 31 having the above-described structure is interposed between the anode edge plate 7 and the interconnector 6 in accordance with the four peripheral edges of the unit cell 1.

In the fuel cell 30 of the present embodiment, the spring plate 32 ′ on the inner peripheral edge 7 b side of the anode edge plate 7 of the anode edge spring 31 having a multi-stage structure and the inner peripheral edge 7 b of the anode edge plate 7 And a seal reinforcing plate 35 is interposed therebetween. The seal reinforcing plate 35 has a thin plate shape, and at least one (one) protruding portion 35a is formed in a portion of the anode edge plate 7 facing the inner peripheral edge 7b along the peripheral direction of the inner peripheral edge 7b. Have been. The protruding portion 35a is formed by bending a corresponding portion of the thin plate toward the inner peripheral edge 7b of the anode edge plate 7 in a convex shape, and the bending line is formed in the peripheral direction of the inner peripheral edge 7b. The directions are parallel. The projecting portion 35a is formed by pressing a corresponding portion of the thin plate by, for example, a press.

In FIG. 1, one peripheral portion 2 of the cell 1 is provided.
Although only the seal reinforcing plate 35 interposed between the inner peripheral edge portion 7b of the anode edge plate 7 and the anode edge spring 31 which are in close contact with a is shown, this seal reinforcing plate 35 is
The four anode edge springs 31 and the anode edge plate 7 corresponding to the four anode edge springs 31 interposed respectively along the four peripheral edges of the cell 1.
Are respectively interposed between the inner peripheral edge portion 7b and the inner peripheral edge portion 7b.

The thickness of the seal reinforcing plate 35 including the protrusion 35a in the stacking direction is such that
In consideration of the fact that the fuel cell 11 and the oxidizing gas 12 are provided also in a region (that is, on a gas flow path) along the surface of the peripheral portion 2a of the unit cell 1 orthogonal to the flow direction of the fuel gas 11 and Stipulated. That is, the anode edge plate 7
The thickness (indicated by a + b in FIG. 2) of the anode 3 and the anode current collector 9 disposed in the rectangular opening H in the stacking direction is the thickness of the seal reinforcing plate 35 in the stacking direction and the edge spring 31. If the sum (a + b ≧ c) of the total thickness (represented by c in FIG. 2) of the anode edge plate 7 in the stacking direction including the protruding portions 32a is equal to or greater than (a + b ≧ c), the gas in the edge spring 13 In order not to reduce the flow cross-sectional area, the thickness in the stacking direction including the protruding portion 35a of the seal reinforcing plate 35 may be determined within a range satisfying the above relational expression.

The cathode edge spring portion has the same structure as the anode edge spring portion shown in FIGS.

According to this configuration, the reaction force of the anode edge spring 31 acts on the contact portion (seal portion) between the inner peripheral edge 7b of the anode edge plate 7 and the peripheral edge 2a of the electrolyte matrix 2 via the seal reinforcing plate 35. I do. At this time,
Since the reaction force concentrates on the protrusion 35a of the seal reinforcing plate 35, the local surface pressure along the protrusion 35a is reduced over the entire periphery 2a of the electrolyte matrix 2 to which the anode edge plate 7 is in close contact. Can work. Therefore, a continuous and strong surface pressure can be applied to the contact portion between the anode edge plate 7 and the electrolyte matrix 2.
Further, the protrusion 35a provided on the seal reinforcing plate 35 is
This has the effect of increasing the strength of the thin plate in the protruding direction, so that a more uniform surface pressure can be applied to the continuous direction of the protruding portion 35a of the seal reinforcing plate 35.

The above-described operation can be similarly obtained at the contact portion between the cathode edge plate 8 and the electrolyte matrix 2.

That is, according to the present configuration, the cell 1 (the electrolyte matrix 2 thereof) and the separator 5 (the edge plate 7 of the separator 5,
8) can be surely brought into close contact with each other by a uniform and strong surface pressure, and a wet seal can be reliably formed. As a result, leakage of the fuel gas and the oxidizing gas, inflow of the battery atmosphere gas, mixing of the fuel gas and the oxidizing gas, and the like can be significantly suppressed, and the battery performance and the reliability of the fuel cell can be improved.

In this configuration, the thickness of the seal reinforcing plate 35 in the stacking direction including the protruding portion 35a is set to the edge spring 31.
Since the gas flow cross-sectional area is set within a range that does not decrease, the wet seal can be reliably formed while maintaining good gas flow.

The protrusion 35a formed on the seal reinforcing plate 35 desirably faces the inner peripheral edge 7b of the edge plate 7 as shown in FIG. 1, and is locally contacted by the protrusion 35a. Surface pressure can be increased.

FIG. 1 shows an example in which one protruding portion 35a of the seal reinforcing plate 35 is provided, but the protruding portion along the peripheral direction of the inner peripheral edge portion 7b of the edge plate 7 is formed as the inner peripheral edge portion. A plurality of rows may be provided along a direction orthogonal to the peripheral direction. With this configuration, the contact surface pressure acting on each protrusion decreases, but, on the other hand, the portion where the contact surface pressure acts on the edge plate and the electrolyte matrix is formed in a plurality of rows. In this case, the unit cell 1 and the separator 5 can be brought into close contact with each other, and there is an advantage that the contact surface pressure acting area is increased. This modification is particularly effective when the pressure difference between the fuel gas and the oxidizing gas and the battery atmosphere gas is small, taking advantage of the above advantages.

Further, as a modification of the present configuration, a seal reinforcing plate interposed between the spring plate and the inner peripheral edge of the edge plate may be provided upside down from FIG. That is, the protruding portion in this modification is formed by bending a corresponding portion of the thin plate in a convex shape so as to face the spring plate.

With this configuration, the two attachment portions (see 32b in FIG. 1) forming the protrusion act on the contact portion between the edge plate (inner peripheral portion) and the electrolyte matrix (peripheral portion). The edge plate and the electrolyte matrix can be brought into close contact with each other at the two attachment portions (seal locations).

(Second Embodiment) FIG. 3 shows an anode edge plate 7 and a seal reinforcing plate 40 interposed between the anode edge plate 7 and an anode spring (not shown) in the stacked fuel cell of this embodiment. FIG. 4 is an enlarged perspective view, and FIG. 4 is a sectional view taken along line BB in FIG.
The anode spring and other components are the first
The description is omitted because it is the same as the embodiment.

According to FIG. 3 and FIG. 4, the seal reinforcing plate 40 of the present configuration is configured as a rectangular opening plate whose center is cut out in a rectangular shape, and the size (area) of the rectangular opening H1. Is substantially equal to the rectangular opening H of the anode edge plate 7.

As in the first embodiment, an edge (peripheral edge) 40a around the rectangular opening H1 of the seal reinforcing plate 40 facing the inner peripheral edge 7b of the anode edge plate 7 is provided. At least one (one) protruding portion 40b is formed along the peripheral direction of the peripheral portion 40a over the entire periphery of the peripheral portion 40a including the corner portion. The seal reinforcing plate 40 is manufactured by, for example, press integral molding.

The cathode edge spring portion has the same structure as the anode edge spring portion shown in FIGS.

Next, the operation of the present configuration will be described in comparison with a conventional edge spring.

That is, in a conventional stacked fuel cell using an edge spring formed by stacking a plurality of spring plates provided with protrusions at a predetermined pitch, the fuel cell is usually aligned with the four edges of a rectangular unit cell. Although four edge springs are interposed between the unit cell and the edge plate, the contact surface pressure is likely to decrease at both ends of each edge spring because the spring plate flat portion to be bent is supported on one side, The wet seal was easily damaged at the corners of the cell.

However, the use of the seal reinforcing plate having the above configuration can make up for the above-mentioned disadvantage. That is, since the seal reinforcing plate 40 is connected at each corner, the adjacent edge springs 31 can be bridged at the corner. In addition, the protruding portion 40b of the seal reinforcing plate 40 is
Is formed continuously over the entire periphery of the cell, the peripheral corner of the cell 1 (electrolyte matrix 2) and the inner peripheral corner of the anode edge plate 7 are formed based on the reaction force of each edge spring 31. , A local surface pressure can be applied to the contact portion through the protrusion 40b of the seal reinforcing plate 40.

The above-described operation can be similarly obtained at the contact portion between the cathode edge plate 8 and the electrolyte matrix 2.

Therefore, in the present configuration, even at the peripheral corner of the cell 1 (electrolyte matrix 2), the electrolyte matrix 2 and the edge plate 7,
8) can be surely brought into close contact with each other by a uniform and strong surface pressure, so that a wet seal can be reliably formed. As a result, similarly to the first embodiment, leakage of the fuel gas and the oxidizing gas and the like can be significantly suppressed, and the cell performance and the reliability of the fuel cell can be improved.

(Third Embodiment) FIG. 5 is an enlarged view of a gas supply / discharge manifold section (particularly, an oxidant gas supply manifold section) in a stacked fuel cell (inner manifold fuel cell) of this embodiment. It is a figure which shows the part (manifold part) in cross section. Note that components other than the manifold section are the same as those in the above-described embodiment, and therefore, the same reference numerals as those in FIGS.

According to FIG. 5, the anode edge plate 7 and the cathode edge plate 8 of the separators 5 and 5 'adjacent to each other in the stacking direction have through holes penetrating the anode edge plate 7 and the cathode edge plate 8 in the stacking direction. A manifold ring part 50 is interposed between the two through holes 25 facing each other with the unit cell 1 interposed therebetween. That is, the through hole 25 of the anode edge plate 7 of the separator 6 is connected to the through hole 25 of the cathode edge plate 8 'of the separator 5' in an airtight manner via the manifold ring 50, and is supplied from outside. The oxidizing gas is supplied to the manifold ring portion 50 and the through-hole 25 as shown by a broken arrow S in FIG.
To the cell 1 along the flow path formed by the cathode edge plates 8, 8 'and the interconnector 6.

The manifold ring portion 50 includes a ring-shaped manifold spring 51 and an insulating ring 52. The manifold spring 51 is formed by laminating a plurality of ring-shaped spring plates 53 and a seal reinforcing ring 54. The body is covered with a spring cover 55.

The end face of the spring cover 55 on the cathode edge plate 8 'side is joined to the inner peripheral edge of the through hole 25 in the cathode edge plate 8' facing the end face by, for example, welding, and the end face on the anode edge plate 7 side is insulated. The inner peripheral edge of the through hole 25 of the anode edge plate 7 is mechanically (non-adhered) in contact with the anode edge plate 7 via the ring 52.

As the insulating ring 52, a ceramic porous body impregnated with a molten salt is used.
A wet seal is formed between (the insulating ring 52) and the anode edge plate 7.

On the other hand, the spring plate 53 is provided on the ring-shaped thin plate with projections at equal pitches along the entire circumferential direction, and the spring plate 53 provided with the projections is provided along the axial direction. The adjacent spring plates 53 are stacked while being shifted in phase. Therefore, the manifold spring 51 can be contracted in the stacking direction of the spring plate 53 by bending the flat portion of the spring plate 53.

A seal reinforcing ring 54 is interposed between the spring plate 53 closest to the anode edge plate 7 among the spring plates 53 and the spring cover 55 adjacent to the insulating ring 52. The seal reinforcing ring 54 is formed of a ring-shaped thin plate, and has at least one (one) ring-shaped protruding portion continuous over the entire circumference along the circumferential direction of the insulating ring 52 on the end surface on the insulating ring 52 side. 54
a is formed. The corresponding portion of the ring-shaped protruding portion 54a is the insulating ring 52.
It is bent and formed so as to face.

Further, a gas flow path ring (not shown) is provided between the cathode edge plate 8 'and the interconnector 6' to block the cathode gas flow path formed by the interconnector 6 'and the cathode edge plate 8'. I do not support it.

The fuel gas supply manifold, the fuel gas discharge manifold, and the oxidant gas discharge manifold have the same configuration as the above-described oxidant gas supply manifold.

According to this configuration, when the stacked fuel cell is tightened in the stacking direction, the manifold spring is held in a state where the gas flow path formed by the interconnector 6 'and the cathode edge plate 8' is held by the gas flow path ring. 51 contracts in the stacking direction, and the height of the oxidizing gas manifold portion changes in accordance with the contraction of the manifold spring 51.

The contraction of the manifold spring 51 causes the reaction force to act on the insulating ring 52 via the manifold spring 51 and the seal reinforcing ring 54, and to move along the insulating ring 52 and the through hole 25 of the anode edge plate 7. It acts on the contact portion with the inner peripheral edge. At this time, the reaction force is concentrated on the ring-shaped protrusion 54a of the seal reinforcing plate ring 54, and the ring-shaped protrusion 54a
Is formed in a ring shape and continuously, so that the entire surface of the insulating ring 52 to which the anode edge plate 7 is in close contact is
A continuous and uniform contact surface pressure along the ring-shaped protrusion 54a can be applied.

The above-described operation is similarly performed in the fuel gas supply manifold, the fuel gas discharge manifold, and the oxidizing gas discharge manifold.

That is, according to this configuration, since a continuous and strong surface pressure can be applied to the contact portion between each edge plate 7, 8 and each manifold portion, the manifold portion is applied to each edge plate 7, 8. The contact can be surely made tight, and the wet seal can be reliably formed. As a result, the sealing performance between the manifold portion and the edge plate (separator) can be maintained at a high level, and leakage of fuel gas and oxidizing gas, inflow of battery atmosphere gas, mixing of fuel gas and oxidizing gas, and the like can be achieved. Can be greatly suppressed, and the cell performance and the reliability of the fuel cell can be improved.

It is desirable that the ring-shaped protrusion 54a formed on the seal reinforcing ring 54 is directed toward the insulating ring 52 as shown in FIG. It is concentrated on the protruding portion of the reinforcing ring, and can maintain a high contact surface pressure.

Although FIG. 5 shows an example in which one ring-shaped protrusion 54a of the seal reinforcing ring 54 is provided, a plurality of concentric rings may be provided. With such a configuration, the contact surface pressure acting on each ring-shaped protrusion is reduced, but on the other hand, the contact surface pressure acts on the insulating ring and the edge plate in a plurality of portions, so that the plurality of portions In this case, the manifold portion and the edge plate (separator) can be brought into close contact with each other, which has the advantage that the contact surface pressure acting area increases. This modification is particularly effective when the pressure difference between the fuel gas and the oxidizing gas and the battery atmosphere gas is small, taking advantage of the above advantages.

Further, as a modification of the present configuration, a seal reinforcing ring interposed between the spring plate 53 and the spring cover 55 adjacent to the insulating ring 52 may be provided upside down from FIG. That is, the ring-shaped protrusion in this modification is formed by bending a corresponding portion of the ring-shaped thin plate in a convex shape so as to face the spring plate.

With this configuration, the ring-shaped protrusion 5
Since the two attachment portions forming 4a act on the contact portion between the manifold portion (insulating ring) and the edge plate (inner peripheral portion), the manifold portion and the edge plate are provided at the two attachment portions (seal portions). And can be brought into close contact with each other.

In the present embodiment, the inner peripheral edge of the through hole 25 of the anode edge plate 7 and the insulating ring 52 are brought into mechanical (non-adhered) contact with each other. The inner peripheral edge of 25 and the insulating ring 52 may be brought into mechanical contact with each other, or both the anode edge plate and the cathode edge plate may be brought into mechanical contact with the insulating ring 52. In this case, a seal reinforcing ring is provided on both insulating rings.

In this embodiment, the ring-shaped projection 5
4a is provided on the end face of the seal reinforcing ring 54 on the insulating ring 52 side over the entire circumference along the circumferential direction of the insulating ring 52. However, even if only a required portion is provided instead of the entire circumference. Good.

Further, according to the first to third embodiments, the anode edge spring and the manifold spring are configured as leaf springs. However, the present invention is not limited to this, and has the necessary elasticity. The spring member may have any structure as long as it does not hinder gas flow.

In the present invention, a molten carbonate fuel cell using an electrolyte matrix formed by molten carbonate as an electrolyte matrix has been described as an example. However, the present invention is not limited to this. A stacked fuel cell using other electrolyte matrices, such as one using phosphoric acid as the electrolyte matrix, may be used.

[0084]

As described above, according to the present invention, the cell (electrolyte matrix) and the separator (edge plate) can be surely brought into close contact with each other by a uniform and strong surface pressure, and the wet seal can be obtained. Can be reliably formed. As a result, leakage of the fuel gas and the oxidizing gas, inflow of the battery atmosphere gas, mixing of the fuel gas and the oxidizing gas, and the like can be significantly suppressed, and the battery performance and the reliability of the fuel cell can be improved.

Further, according to the present invention, since a continuous and strong surface pressure can be applied to the contact portion between the separator (edge plate) and each manifold portion, the manifold portion can be securely brought into close contact with the separator. As a result, a wet seal can be reliably formed. As a result, the sealing performance between the manifold and the separator can be maintained at a high level, and leakage of the fuel gas and the oxidizing gas, inflow of the battery atmosphere gas, mixing of the fuel gas and the oxidizing gas, and the like are greatly reduced. And the cell performance and the reliability of the fuel cell can be improved.

[Brief description of the drawings]

FIG. 1 is an enlarged view showing a part of an anode edge spring part in a stacked fuel cell according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is an enlarged perspective view showing an anode edge plate and a seal reinforcing plate in a stacked fuel cell according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along the line BB in FIG. 3;

FIG. 5 is an enlarged sectional view showing an oxidizing gas supply manifold portion in a stacked fuel cell according to a third embodiment of the present invention.

FIG. 6 is an exploded perspective view showing a single cell portion of a conventional stacked fuel cell.

FIG. 7 is a sectional view taken along the line CC in FIG. 6;

FIG. 8 is an enlarged view showing a part of an anode edge spring portion in a conventional stacked fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single cell 2 Electrolyte matrix 2a Peripheral part of electrolyte matrix (cell) 3 Anode 4 Cathode 5 Separator 6 Interconnector 7 Anode edge plate 7b Inner peripheral part of anode edge plate 8 Cathode edge plate 8b Inner peripheral part of cathode edge plate 25 Through hole 26 Manifold ring 30 Stacked fuel cell 31 Edge spring 32 Spring plate 32a Projection 35, 40 Seal reinforcement plate 35a, 40b Projection 40a Inner peripheral edge of seal reinforcement plate 50 Manifold ring part 51 Manifold spring 52 Insulation ring 53 Ring Spring Plate 54 Seal Reinforcement Ring 54a Ring Projection 55 Spring Cover

Claims (9)

[Claims] A plurality of unit cells each having an electrolyte matrix sandwiched between an anode and a cathode are stacked, and separators for guiding fuel gas to the anode and oxidizing gas to the cathode are separated from each other. A stacked fuel cell interposed between cells, wherein the separator is an interconnector formed to separate the fuel gas flow path and the oxidant gas flow path, and a peripheral edge of the interconnector. The central portion disposed on the anode adjacent side and the cathode adjacent side of the surface of the interconnector so as to sandwich the portion has two edge plates with openings, and the inner peripheral edge around the opening of each edge plate is A fuel gas flow path and an oxidizing gas flow path are formed between the edge plate and the interconnector so as to be in contact with the periphery of the electrolyte matrix. A current collector for interposing the interconnector and the anode central portion and the interconnector and the cathode central portion to support the anode and the cathode and to secure the fuel gas flow path and the oxidizing gas flow path; In the stacked fuel cell having the edge plate and the electrolyte matrix, the inner peripheral edge is interposed between the inner peripheral edge of each edge plate and the interconnector, and the inner peripheral edge is pressed against the peripheral edge of the electrolyte matrix by elastic force. In order to reinforce the adhesive force between the edge plate and the electrolyte matrix, between the edge spring and the inner peripheral edge of each of the edge plates, at a portion opposed to the inner peripheral edge portion. A stacked fuel cell comprising a reinforcing member provided with a protruding portion along a peripheral direction thereof. 2. The stacked fuel cell according to claim 1, wherein the projecting portion is provided toward an inner peripheral edge of the edge plate. 3. A plurality of edge springs are provided at a portion facing the inner peripheral edge of the edge plate along a direction orthogonal to a peripheral direction of the inner peripheral edge, and are arranged at a predetermined pitch in the peripheral direction. 3. The lamination type according to claim 1, wherein a plurality of spring plates having protrusions are formed by laminating the plurality of spring plates, and the protrusions of the spring plates adjacent in the stacking direction are shifted from the other adjacent protrusions by a half pitch. Fuel cell. 4. The reinforcing member is configured as an opening plate having an opening having substantially the same size as the opening of the edge plate, and the projecting portion is an inner peripheral edge of the edge plate in the opening plate. 4. The fuel cell stack according to claim 3, wherein the fuel cell is provided continuously over the entire periphery of the electrolyte matrix at a portion opposed to the fuel cell. 5. A plurality of unit cells each comprising an electrolyte matrix sandwiched between an anode and a cathode, and a plurality of unit cells each having a separator for leading a fuel gas to the anode and an oxidant gas to the cathode with the oxidant gas being separated from each other. In the stacked fuel cell interposed therebetween, a plurality of holes provided in the separator to independently guide the fuel gas and the oxidizing gas and penetrating the separator in the stacking direction, A manifold portion interposed between the through holes of adjacent separators through which the through holes are air-tightly communicated, the manifold portion is a ring-shaped manifold spring that can be contracted in the laminating direction, and the manifold spring. An electrically insulating insulation interposed between at least one of the adjacent separators and closely attached to the separator. The manifold spring is provided with a protruding portion along a circumferential direction of the insulating ring at a portion facing the insulating ring in order to reinforce the adhesion between the insulating ring and the separator. A stacked fuel cell comprising a reinforcing ring. 6. The stacked fuel cell according to claim 5, wherein the protruding portion is disposed toward an inner peripheral edge of the insulating ring. 7. The manifold spring includes a plurality of protrusions provided at a portion facing the seal reinforcing ring along a circumferential direction of the reinforcing ring and arranged at a predetermined pitch in the circumferential direction. A laminate formed by laminating a plurality of ring-shaped spring plates having such that one protruding portion of the adjacent ring-shaped spring plates is shifted by half a pitch from the other protruding portion adjacent thereto, and 7. A structure in which the laminate is covered with a spring cover.
The stacked fuel cell according to the above. 8. The stacked fuel cell according to claim 7, wherein the protrusion of the reinforcing ring is provided continuously over the entire circumference of the insulating ring. 9. The stacked fuel cell according to claim 1, wherein the stacked fuel cell is a molten carbonate fuel cell using an electrolyte matrix formed of a molten carbonate as the electrolyte matrix.