JPH0349160A - Laminated fuel cell - Google Patents

Abstract

PURPOSE:To obtain good sealing property, prevent the mixing of oxidizer gas and fuel gas, and prevent leakage by providing ring-shaped seal members inserted with insulators between multiple ring-shaped metal members between adjacent upper and lower separators of manifolds. CONSTITUTION:Ring-shaped seal members 14 are provided in oxidizer gas feed/ exhaust manifolds 4 and 5 and fuel gas feed/exhaust manifolds 6 and 7, ring- shaped metal members 16a and 16b of ring-shaped seal members 14 and adjacent separators 3 are welded together, thus both gases are completely sealed for feeding end exhausting, and oxidizer gas and fuel gas are not mixed. When respective members have approximate linear expansion coefficients at connection sections between ring-shaped metal members 16a and 16b and insulators 15 and welded sections between ring-shaped metal members 16a and 16b and separators 3, no distortion is generated by the difference in thermal expansion, and durability and the sealing property can be secured.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to stacked fuel cells.

(Prior art) In general, a fuel cell is formed by applying a positive electrode plate and a negative electrode plate to both sides of an electrolyte plate, and supplying oxidizing gas to the positive electrode plate side and fuel gas to the negative electrode plate side, thereby forming a unit cell. It converts chemical energy directly into electrical energy based on a chemical reaction between a gas and an electrolyte.

However, the output voltage of the unit cells as described above is as low as IV at most, and in order to obtain a practical voltage, a plurality of unit cells must be stacked in series.

FIG. 24 is a perspective view showing the appearance of a conventional stacked fuel cell. For example, an electrolyte plate 1 formed into a sheet by mixing an electrolyte of a mixed alkali carbonate of lithium carbonate and potassium carbonate and lithium aluminate fine powder, and a gas diffusion plate made of porous sintered nickel plates (not shown) on both sides. Applying electrodes, supplying an oxidant gas containing oxygen and carbon dioxide to the positive electrode side and supplying a fuel gas containing hydrogen to the negative electrode side to form a unit cell (2), and connecting the electrolyte plate 1 and a conductive separator. 3 are alternately stacked one on top of the other, and are tightened with bolts (not shown) to form a stacked fuel cell.

Further, this stacked fuel cell is provided with manifolds 4 and 5 for supplying and discharging oxidant gas, and manifolds 6 and 7 for supplying and discharging fuel gas.

Further, as shown in detail in FIG. 25, which is a vertical cross-sectional view, the separator 3 is composed of a separator body 8 and a side wall 9 surrounding the separator body 8, and electrolyte plates 1 and 1 are provided on both sides of the side wall 9. A flat abutting surface 10 is formed which contacts the end of the holder. A gas layer 11 made of oxidizing gas and a gas layer 12 made of fuel gas surrounded by the electrolyte plate 1 and the separator 3 are communicated with the manifold 4 or 6 through the through hole 13 and supplied with a predetermined gas, The liquid is discharged through a through hole 13 into a manifold 5 or 7 shown in FIG. 24, respectively.

In the stacked fuel cell configured as described above, in order to prevent the oxidizing gas and the fuel gas from mixing, and to prevent these gases from leaking to the outside from the side wall 9, It is necessary to seal between the abutment surface 10 of the separator 3 and the electrolyte plate 1 in contact therewith. For this reason,
After stacking conventional unit batteries, the operating temperature of the battery is 650℃.
A wet seal method is used in which the temperature is raised to ℃ and sealed with an electrolyte that melts as the temperature rises.

In other words, the electrolyte in the electrolyte plate described above has a temperature of 4.
It melts at a eutectic temperature of 88° C., and this melt fills the gap existing between the end of the electrolyte plate 1 and the contact surface 10 of the separator 3, thereby providing a gas seal.

(Problems to be Solved by the Invention) However, in conventional stacked fuel cells that employ the wet seal method as described above, variations in the wettability of the electrolyte plate, the applied pressure, or the thickness f[of each part of the electrode] may occur. ,
Influenced by variations in the machining accuracy of the contact surface of the separator, leakage distance, etc., there is a risk that the seal between the separator and the electrolyte plate will be insufficient. In particular, if the sealing is insufficient at the boundary between the manifold and the separator abutting surfaces as described above, there is a problem in that the oxidizing gas and the fuel gas mix and react, impairing the effective use of the reaction gas. . or,
There was a risk of leakage from each manifold to the outside air.

Therefore, the present invention particularly provides a stacked fuel cell in which electrolyte plates and separators are alternately stacked so that an oxidant gas layer and a fuel gas layer are arranged on both sides of the electrolyte plate to form a unit cell. The object of the present invention is to provide a stacked fuel cell that has good sealing properties at the boundary between the contact surface of the manifold and the separator, and that does not cause mixing of oxidizing gas and fuel gas and prevents leakage. do.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention stacks a plurality of electrolyte plates, positive electrodes, negative electrodes, and separators, and supplies gas to the gas path in contact with the electrodes. A stacked fuel cell provided with a discharge manifold, characterized in that a ring-shaped sealing member formed by interposing an insulator between a plurality of ring-shaped metal members is provided between adjacent separators in the manifold. It is.

(Function) In the stacked fuel cell of the present invention, a ring-shaped seal member is constructed with an insulator interposed between a plurality of ring-shaped metal members, and each ring-shaped metal member of the ring-shaped seal member and the adjacent ring-shaped metal members in the manifold Separators are sealed between each manifold to prevent the gases guided to the respective manifolds from leaking to the outside.Therefore, the fuel gas and oxidizer gas do not mix, and the necessary gases are supplied to the necessary flow paths. It becomes possible to exhaust the air.

(Example) The present invention will be explained in detail below.

In the embodiment shown in FIGS. 1 and 2, gas layers 11 and 12 of oxidizing gas and fuel gas are formed on both sides of the electrolyte plate 1, and the electrolyte plate 1 and separator 3 are
and in particular, each manifold 4 to 7.
A ring-shaped seal member 14 is provided inside the ring.

That is, referring to FIG. 2 showing the oxidizing agent supply manifold 4, the ring-shaped seal member 14 is a ring-shaped seal member having a rectangular cross section and made of a ceramic material such as alumina or zirconia with high electrical insulation properties. Ring-shaped metal members 16a, 16 are provided on both upper and lower surfaces of the insulator 15.
(b) are placed one on top of the other, and the contact surfaces are closely bonded by brazing, ceramic bonding, or the like. Then, a gap S is provided so that the ring-shaped seal members 14 formed in this way are not in contact with each other, and this gap S is used to connect the oxidizing gas layer 11 to be connected to the manifold 4.
and the ring-shaped metal member 16a.

The outer periphery of 16b is welded to two adjacent separators 3 all around.

The same applies to the other manifolds 5.6 and 7.

In the above configuration, adjacent ring-shaped seal members 1
A predetermined gas can be supplied to a predetermined gas layer 11.12 through a through hole 13 from a gap S formed between 5. Discharge to 7.

Therefore, in the stacked fuel cell of this example, the ring-shaped seal member 14 is provided inside the oxidizing gas supply/discharge manifolds 4, 5 and the fuel gas supply/discharge manifold 6. ring-shaped metal member 16a,
Since the separators 16b and the adjacent separators 3 are welded together, the supply and discharge of both gases are completely sealed, and the oxidizing gas and the fuel gas do not mix.

Further, the coupling portion between the ring-shaped metal members 16a, 16b and the insulator 15, and the ring-shaped metal members 16a, 1
If the linear expansion coefficients of the respective members are approximated at the welded portion between the separator 6b and the separator 3, distortion due to differences in thermal expansion will not occur, and durability and sealing performance can be ensured.

Furthermore, since the insulator 15 is made of a ceramic material, it can have high electrical insulation, and even if it is made considerably thin, the electrical insulation between the separators 3 can be ensured in a thin space.

In the above description, the ring-shaped metal members 16a and 16b of the ring-shaped seal member 14 and the adjacent separators 3 are welded together, but for example, the outer peripheral edges of the ring-shaped metal members 16a and 16b are It may be fitted into grooves previously provided on the inner circumferential surfaces of the manifolds 4 to 7 and sealed.

Further, in the sealing method using the groove, the ring-shaped metal members 16a and 16b having a coefficient of linear expansion larger than that of the separator 3 are incorporated into the groove, and the gap created in the groove is formed by a thermal expansion difference. It can also be sealed using.

The embodiment shown in FIG. 3 is an example in which the ring-shaped seal member 14 shown in FIG. 2 is modified into a flexible structure with respect to the plane direction defined by the electrolyte plate 1 and the stacking direction of the fuel cell.

That is, the ring-shaped sealing member 17 of this example consists of two ring-shaped metal members 18a and 18b, an insulator 19 and a thin flat plate 18c interposed between them, and one insulator and the ring-shaped metal member 18b. The metal members 18a and 1.8b are joined to the inner and outer peripheral surfaces of the one insulator, respectively, and the ends of the ring-shaped metal members 18a and 18b to be joined to the one insulator are connected in opposite directions. It has a U-shaped cross section. The other end surface of the ring-shaped metal member 18a is welded to the corresponding adjacent separator 3 via the thin plate 18C, and the other end surface of the ring-shaped metal member 18b is welded directly to the corresponding adjacent separator 3.

Therefore, the ring-shaped seal member 17 of this example has the same sealing performance and durability as the example shown in FIG. It is possible to absorb strain due to the difference in thermal expansion between the insulator 3 and the insulator 19, and it is possible to further improve sealing performance and durability without straining the bonded surfaces. or,
When welding with the separator 3, errors in component manufacturing can be absorbed and the welding work can be easily performed.

Furthermore, since the thin flat plate 18C has a flexible structure in the stacking direction, stable performance can be provided even when the thickness of the electrolyte plate 1 changes.

In the embodiment shown in FIG. 4, one end of the ring-shaped metal members 18"a and 18"b of the ring-shaped seal member 17° and an insulator 19" are respectively attached to the ring-shaped seal member 17 shown in FIG. They are joined at corresponding upper and lower planes, and the other ends of the ring-shaped metal members 18''a and 18'b are connected to the thin flat plate 18.
°c and 18"d, respectively, and are joined at the upper and lower planes corresponding to the ring-shaped metal members 18°a and 18"d.
The cross-sectional shape of "b" is roughly U-shaped and wavy. Therefore, by joining them at corresponding upper and lower planes, the creep deformation of the electrolyte plate 1 (this creep deformation is shown by arrow A in the figure) is prevented. (deforms in the direction of contraction with respect to the upper and lower planes), a compressive load is applied to each joint, increasing the joint strength.Furthermore, the ring-shaped metal member 18°a.

By making the shape of 18゛b approximately U-shaped and wavy, the flexibility in the planar direction defined by the electrolyte plate is further increased, the shear load applied to the joint is reduced, and stable performance can be provided. In addition, 1g of ring-shaped metal members'
! , 18'b are located on the inner diameter side and the outer diameter side with respect to the insulator 19', thereby achieving a flexible configuration that is effective even in a narrow space.

In the embodiment shown in FIG. 5, raised portions 18θ and 18° are provided on the inner periphery of the ring-shaped metal member 18”a and the outer periphery of the ring-shaped metal member 18”b of the ring-shaped seal member 17°. At the same time, the raised portions 18''e, 1 of the ring-shaped metal members 18°'a, 18''b of the thin flat plates 18°c, 18''d
There is a rising part 18°'g, 18 in the part opposite to 8°°r.
``h'' is provided, and the end faces of the rising portions are welded together.

Ring-shaped metal members 18"a, 18"b and thin flat plate 1
8"C118°'d (direct separator if a thin flat plate is not provided) and a rising part 18 provided respectively.
By welding the ends °'e, 18"f and 18°'g, 18"h, deformation occurring in the partition plate 8 or the abutment surface 10 due to welding shrinkage, thermal effects, etc. is reduced.

Therefore, smooth contact is provided between the electrolyte plate 1 and the contact surface 10, and uniform spacing is provided between the electrolyte plate 1 and the partition plate 8. It goes without saying that the position, shape, etc. of the raised portion can be changed as appropriate. In this embodiment, the separator 3 itself is made of a thin plate or a thin flat plate at 18°C 118°C.
This is particularly effective when configured with -d.

The embodiment shown in FIG. 6 differs from the ring-shaped seal member 17 shown in FIG. Member 21a.

A thick portion is provided to increase the thickness of 21b.

The ring-shaped metal members 21a and 21b and the insulating part 22
Materials are selected so that the coefficient of linear expansion is approximate.

In the ring-shaped sealing member 20 of this example, the linear expansion coefficients of the ring-shaped metal members 21a, 2 lb and the insulator 22 are approximate, so that the linear expansion coefficient and the linear expansion coefficient of the separator 3 are different at the joint surface between the two. Thermal stress generated due to the difference in the metal members 21a, 21. It can be absorbed into the thin part of b.

In the embodiment shown in FIG. 7, a ring-shaped small member 23 is used as a ring-shaped seal member 20 shown in FIG. 24b and metal rings 25a, 25b, which are divided and joined together. The insulator 26 is similar to that of FIG.

The ring-shaped sealing member 23 of this example is manufactured by cutting, for example, a tubular member into ring-shaped metal members 24a and 24b manufactured by sheet metal processing, instead of the ring-shaped metal members 21a and 2 lb shown in FIG. Metal rings 25a, 25
Since b can be manufactured by, for example, welding, manufacturing is easy.

The embodiment shown in FIG. 8 differs from the ring-shaped seal member 17 shown in FIG. It is joined together.

In the ring-shaped seal member 27 of this example, the insulator 29 is held from the side and upper and lower sides, so the bonding strength between the insulator 29 and the ring-shaped metal members 28a and 28b is increased.

The embodiment shown in FIG. 9 differs from the ring-shaped seal member 17 shown in FIG. They are joined from both sides.

The ring-shaped seal member 30 of this example has sufficient bonding strength and is a simple L-shaped combination, so it is easy to manufacture.

In the embodiment shown in FIG. 10, the ring-shaped metal members 34a and 34b of the ring-shaped seal member 33 are joined to the ring-shaped seal member 30 shown in FIG. It is something. The ring-shaped seal member 33 of this example has a bonding strength similar to or higher than that of the ring-shaped seal member 30 of FIG.
It is easy to position the bond between a, 34b and the insulator 35.

The embodiment shown in FIG. 11 differs from the ring-shaped seal member 17 shown in FIG. At the same time, the ring-shaped metal member 3
The joining ends of 7a and 37b are both formed into a symmetrical arcuate cross section. Further, a constriction 37k is provided between this arc portion and the separator 3.

In the ring-shaped seal member 36 of this example, since the ring-shaped metal members 37a and 37b have the same shape, they can be used in common, and manufacturing costs can be reduced. or,
The constriction 37k allows the structure to be flexible in the stacking direction of the fuel cell and in a direction perpendicular thereto, and can absorb strain caused by thermal expansion.

The embodiment shown in FIG. 12 is a ring-shaped metal member 37a of the ring-shaped seal member 36 shown in FIG.

The metal members 40a and 40b of the ring-shaped sealing member 39 are shaped like an ellipse, and have straight hairs so that the ends of the metal members 40a and 40b connected to the insulator 41 are vertically joined from above and below to the arcuate portion of the ring-shaped seal member 37b.

In the ring-shaped seal member 39 of this example, as in the embodiment shown in FIG. It can be manufactured. moreover,
Since the straight line length is provided and the tip is sealingly connected to the insulator 41, the sealing performance can be improved. That is, strain absorption due to thermal expansion or deformation of the circular arc portion at this time suppresses peeling of the straight portion hair and the insulator 41 even further in the straight portion.

In the embodiment shown in FIG. 13, in contrast to the ring-shaped seal member 17 shown in FIG. Furthermore, a ring-shaped metal member 4 is inserted into the slit provided on both the upper and lower surfaces of the insulator 44.
The ends of 3a and 43b are fitted into a slit connection.

Materials are selected so that the coefficient of linear expansion of the ring-shaped metal members 43g and 43b is slightly larger than that of the insulator 44.

In the ring-shaped seal member 42 of this example, the gap created between the grooves provided on the upper and lower surfaces of the insulator 44 and the joint ends of the ring-shaped metal members 43a, 43b is caused by the difference in thermal expansion between the ring-shaped metal members 43a and 43b. 43b, the sealing performance is improved, and the ring-shaped metal members 43a, 43b and the insulator 44 are firmly connected.

The embodiment shown in FIG. 14 is a modification of the embodiment shown in FIG. 2, in which the ring-shaped metal member and the insulator are joined by press-fitting or tightening.

That is, the ring-shaped metal members 46a and 46b of the ring-shaped seal member 45 of this example have a ring wall 46R raised along the inner peripheral surface of the insulator 47, and the ring wall 46R and the insulator 47 are press-fitted. It is joined by staking.

Therefore, the ring-shaped seal member 45 of this example has a strong integral structure by press-fitting the ring-shaped metal members 46a, 46b and the insulator 47, and can provide excellent sealing performance. Further, the ring-shaped metal member 46a,
Since the insulator 46b and the insulator 47 can be joined without using ceramic bonding or the like, manufacturing thereof is easy.

Furthermore, when the separator 3 is made into a thin plate structure, the ring-shaped metal members 46a, 46b can be used as separator constituent members as they are, and more efficient manufacturability can be achieved.

The embodiment shown in FIG. 15 is an improvement of the embodiment shown in FIG.
The inner circumferential surface of the ring wall 50R of the ring-shaped metal members 50a, 50b is formed into a V-shaped cross section, and the ring wall 50R of the ring-shaped metal members 50a, 50b is formed along this V-shaped portion.
This is an example of joining by press-fitting or staking.

Therefore, in the ring-shaped sealing member 48 of this example, by making the insulator 49 V-shaped, due to the difference in linear expansion coefficient between the insulator 49 and the ring-shaped metal members 50a and 50b, the ring wall 5OR is The insulator 49 and the ring-shaped metal member 50a slide along the
, 50b, pressure is applied to the contact surface with the contact surface with the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface of the contact surface with the contact surface is subjected to pressure, thereby achieving better sealing performance.

The embodiment shown in FIG. 16 is also an improvement of the embodiment shown in FIG.
The inner circumferential surface of the ring wall 53R of the ring-shaped metal members 53a, 53b is formed into a circular arc shape in cross section.
This is an example of joining by press-fitting or staking.

Therefore, in the ring-shaped sealing member 51 of this example, since the insulator 52 is formed into an arc shape, the ring wall 53R is shaped into an arc shape due to the temperature rise due to the difference in linear expansion coefficient between the insulator 52 and the ring-shaped metal members 53a and 53b. The insulator 52 and the ring-shaped metal member 53a,
Pressure acts on the contact surface with 53b, allowing for better sealing performance.

The embodiment shown in FIG. 17 is a ring wall 46R of the ring-shaped seal member 45, 48, 51 shown in FIGS. 14 to 16.
, 50R, and 53R at appropriate intervals to form a ring wall 54R, and the ring wall 54R and the insulator 55 are joined by press-fitting or staking.

Therefore, since the ring wall 54R of this example has an appropriate number of slits SL, compared to the embodiment shown in FIGS. 14 to 16,
Press-fitting or caulking of the ring wall 54R and the insulator 55 can be easily performed, and the ring-shaped seal member 56 can be manufactured easily.

In the embodiment shown in FIG. 18, the ring walls 46R, 50R, and 53R of the ring-shaped seal member 45° 48.51 shown in FIGS. 14 to 16 with respect to FIG. The ring walls 57R, 58R and the insulator 59
This is an example of joining by press-fitting or staking.

Therefore, in the ring-shaped seal member 60 of this example, since the concave and convex portions are opposed to each other, the insulator 59 can be more closely joined to the ring-shaped seal member 60 compared to the embodiment shown in FIG. can be easily provided within the thin space between the separators 3.

The embodiment shown in FIG. 19 differs from the embodiment shown in FIG. 14 in that two wetting materials 63a and 63b are bonded to both sides of the insulator 62 of the ring-shaped seal member 61 to form a wetting block 64. , this wet block 64 and the ring-shaped metal member 65
This is an example in which parts a and 65b are joined by press-fitting or staking.

More specifically, the wetting materials 63a and 63b are made of a member such as the electrolyte plate 1 shown in FIG. 25, which melts at high temperatures and becomes wet on its surface, and the surface thereof and the ring A sealing function is provided between the shaped metal members 65a and 65b.

Therefore, in the ring-shaped seal member 61 of this example, the wetting material 6
Since members similar to those of the electrolyte plate 1 were used as the members 3a and 63b, the wetting materials 63a and 63b were used during battery operation.
The surfaces of are in a wet state to produce a molten material, and this molten material is attached to the ring-shaped metal members 65a, 65b and the wetting material 63a,
It is possible to fill the gap existing between the rings 63b and improve the sealing performance of the ring-shaped seal member 61.

Further, in this case, if the linear expansion coefficients of the ring-shaped metal members 65a, 65b and the separator 3 are approximated, the ring-shaped metal members 65a, 65b will not be strained due to thermal expansion, and the sealing performance can be improved. . In addition, since the wetting members 63a and 63b generally have a large coefficient of linear expansion, the thermal expansion of the wetting block 64 is larger than the thermal expansion between adjacent separators 3. The contact pressure increases, and the sealing performance of the ring-shaped seal member 61 can be further ensured.

In the above explanation, the wet block 64 is divided into the insulating material 62 and the wet materials 63a and 63b, but it is not necessary to divide the wet block. Blocks may also be used.

Furthermore, in order to ensure sealing performance, members similar to those of the electrolyte plate 1 were used as the wetting materials 63a and 63b, but any member that is easily flexible at the operating temperature of the battery may be used. For example, materials such as ceramics molded into thin paper, which easily expand and contract at battery operating temperatures, or materials such as silver waves, which are highly malleable and can be processed into thin pieces, soften and deform at battery operating temperatures. Easy members may be used.

The embodiment shown in FIG. 20 is a modification of the embodiment shown in FIG. Wetting rings 63'a, 63' within 62°a, 62°b
b is inserted to form a wet block 64.

More specifically, the wetting rings 63"a, 63°b are made of a member that melts at a high temperature and its surface becomes wet, and the surface and the ring-shaped metal members 65"a, 65"
``b'' has a sealing function. Therefore, during battery operation, the surfaces of the wet rings 63°a and 63'b become wet, producing a molten material, and this molten material is attached to the ring-shaped metal member. 65"a, 65'b and the wetting ring 6
It is possible to fill the gap existing between 3°a and 63°b and improve the sealing performance of the ring-shaped seal member 61''.Here, by providing the grooves 62°a and 62'b, the melting It becomes possible to reduce the leakage of materials.Furthermore, if the respective wetting rings 63°a and 63°b are constructed of members having different temperature ranges in which they become wet,
It is possible to widen the sealable temperature range. In addition, in this example, two full grooves 62°a and 62'b are shown, but it is of course possible to configure them with one or more grooves, and furthermore, the grooves 62°a and 62°b can be formed in a ring shape. It is also possible to provide the metal members 65'a and 65°b.

The embodiment shown in FIG. 21 has a ring-shaped seal member 66 that is substantially the same as the embodiment shown in FIG.
A dispersed phase 68 made of a metal having a larger coefficient of thermal expansion than the insulator is dispersed in the insulator 67. It is preferable that the dispersed phase 68 be distributed more densely as it approaches the ring-shaped metal members 69a and 69b, and more sparsely in the center. Further, the dispersed phase 68 is distributed to such an extent that the dispersed phases do not come into contact with each other in the entire area or a part of the insulator 67.
Insulation is maintained between the ring-shaped metal members 69a and 69b on both sides of the ring.

In this way, by mixing the dispersed phases at a volume ratio that prevents them from contacting each other and compositing them by sintering, etc., the thermal expansion coefficient of the insulator can be adjusted to the same level as that of the insulator single phase without impairing the inherent insulation properties of the insulator. Compared to the case of , it is possible to make the coefficient of thermal expansion closer to that of the ring-shaped metal member. As a result, the adhesiveness of ceramic bonding between the insulator and the ring-shaped metal member during manufacturing is improved, as well as the difference in expansion during temperature fluctuations that may cause the interface between the ring-shaped metal member and the insulator to peel off. As a result, a strong bonding interface can be obtained as a result of the thermal stress caused by the bonding being suppressed to be lower than that in the case of bonding an insulator made of a single insulating phase and a ring-shaped metal member.

The embodiment shown in FIG. 22 also has a ring-shaped seal member 70 that is substantially the same as the embodiment shown in FIG.
Ring-shaped metal members 73a and 73 joined to insulator 71
A dispersed phase 72 having a smaller coefficient of thermal expansion than the metal member is dispersed and composited near the joint on the b side.

In this way, by dispersing and compounding a substance with a small coefficient of thermal expansion in the form of particles or fibers in a part of the ring-shaped metal member near the bonding interface between the insulator and the ring-shaped metal member, the ring-shaped metal member near the bonding interface is The coefficient of thermal expansion of the metal member can be made closer to that of the insulator 71 than in the case of a single metal phase. The local thermal stress that could cause the metal to peel off can be suppressed to a lower level than in the case of a single metal phase.

The embodiment shown in FIG. 23 also has a ring-shaped seal member 74 that is substantially the same as the embodiment shown in FIG.
A composite material layer 76 is sandwiched between an insulator 75 and ring-shaped metal members 77a and 77b. The insulator phase and the composite material layer 76 made of an insulator, etc., and a metal are bonded by combining a powder layer made of the insulator raw material and a separately mixed insulator, etc., and a metal layer during sintering during the production of the insulator. Powder layers made of composite powder or the like may be stacked and sintered.

In this way, when the insulator and the ring-shaped metal members are directly joined by interposing a composite layer made of an insulator and metal between the insulator 75 and the ring-shaped metal members 77a and 77b, Compared to this, bondability is improved, and the difference in thermal expansion coefficient between the constituent layers sandwiching the bonding interface is also reduced, and the occurrence of thermal stress due to the difference in thermal expansion that may cause separation of the interface is also reduced.

The adhesive strength of the composite metal can be increased by selecting a metal that easily diffuses into each other with the metal constituting the ring-shaped metal member, or by mixing another binder material.

In this embodiment, the composite material layer 76 can be formed in multiple stages, and from the insulator 75 side, ring-shaped metal members 77a, 77
The effect can be further improved by gradually increasing the expansion coefficient toward the b side.

As described above, in the embodiments shown in FIGS. 2 to 23, both gases can be completely sealed within the manifold using the ring-shaped sealing member, so the problem of gas mixing between the manifolds can be solved. In addition, there is no need to provide an unnecessary long leakage prevention distance around the manifold using a wet seal method, and a compact stacked fuel cell with reliable sealing performance can be constructed.

In the above embodiment, the separator 3 and the ring-shaped metal member were joined by welding, by fitting the ring-shaped metal member into a groove provided in the separator 3, or by contacting without providing a groove. The joining method is not limited to these, and an appropriate joining method may be adopted depending on the design of the ring-shaped seal member.

In addition, in order to increase the contact distance between the bonding surfaces of the insulator and the ring-shaped metal member, for example, ring-shaped unevenness is provided on both end surfaces of the insulator, and these are fitted into the unevenness provided on the ring-shaped metal member. Good too.

Furthermore, in the embodiments shown in FIGS. 3 to 13 and 20 to 23, the ring-shaped metal member is deformed into a U-shaped cross section, an L-shaped cross section, etc. for ease of manufacturing. Although the ring-shaped metal member has a flexible structure, the shape of the ring-shaped metal member is not limited to this. Furthermore, Figures 14 to 1
The ring-shaped metal member shown in FIG. 9 may have a flexible structure like the ring-shaped metal members shown in FIGS. 3 to 13 and 20 to 23. The wet blocks 64, 64° shown in the figure can be applied to the ring-shaped seal members shown in FIGS. 15 to 18, and the configurations of the respective embodiments can be combined as appropriate.

The present invention is not limited to the above-mentioned embodiments, but can be implemented in other appropriate modes by making appropriate design changes.

[Effects of the Invention] As described above, since the present invention is a stacked fuel cell as described in the claims, a unit cell is constructed by arranging an oxidizing gas layer and a fuel gas layer on both sides of an electrolyte plate. In a stacked fuel cell in which the electrolyte plates and separators are alternately stacked, a ring-shaped seal member is configured between two ring-shaped metal members with an insulating part interposed therebetween, and the ring-shaped seal member A seal is formed between each metal member and an adjacent separator in the manifold, and the gas guided to each manifold is cut off by this seal, so that mixing of gases does not occur. Furthermore, since each manifold and the outside air can be effectively sealed, there is no need to take an unnecessarily long leakage prevention distance, and a compact fuel cell with reliable sealing performance can be constructed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a stacked fuel cell according to an embodiment of the present invention, FIG. 2 is a detailed view of a ring-shaped seal member shown in the direction of the arrow ■ in FIG. 1, and FIG. 3 is a diagram of another embodiment. An example is shown, and a detailed view corresponding to FIG. 2, and FIGS. 4 to 16 are sectional views showing other embodiments and further enlarging the sectional view corresponding to FIG. 3,
FIG. 17 shows another embodiment, an enlarged view of the ring wall seen from arrow Xv in FIG. 16, and FIG. 18 shows another embodiment,
An enlarged view corresponding to FIG. 17, FIG. 19 shows another embodiment,
4 to 16, and FIGS. 20 to 23 respectively show other embodiments, a sectional view corresponding to FIG. 3 is further enlarged, and FIG. 24 is a conventional A perspective view of the stacked fuel cell used to explain the example, Figure 25 is the x in Figure 24.
It is a longitudinal cross-sectional view taken along the line xn-xxn. 1... Electrolyte plate (2)... Unit cell 3... Separator 4.5, 6.7... Manifold 11... Oxidizing gas layer 12... Fuel gas layer 13... Connection Hole 14.17, 20, 23, 27, 30, 33° 36.3
9,42,45,48,51,56.661゜66゜70゜74...Ring-shaped seal part

Claims (14)

[Claims] (1) In a stacked fuel cell in which a plurality of electrolyte plates, positive electrodes, negative electrodes, and separators are laminated, and a manifold is provided for supplying and discharging gas to a gas path in contact with the electrodes, the space between adjacent upper and lower separators in the manifold A stacked fuel cell characterized in that a ring-shaped seal member is provided with an insulator interposed between a plurality of ring-shaped metal members. (2) The stacked fuel cell according to claim 1, wherein the ring-shaped seal member has a flexible structure with respect to the stacking direction of the stacked fuel cell. (3) The stacked fuel cell according to claim 1, wherein the ring-shaped seal member has a flexible structure with respect to a plane direction defined by the electrolyte plate. (4) The stacked fuel cell according to claim 1, wherein each ring-shaped metal member of the ring-shaped seal member and the insulator are connected by slits. (5) The stacked fuel cell according to claim 1, wherein each ring-shaped metal member of the ring-shaped seal member and the separator are sealed in a sealed connection. (6) The stacked fuel cell according to claim 5, wherein each ring-shaped metal member of the ring-shaped seal member and the separator are sealed by welding, brazing, or ceramic bonding. Characteristic stacked fuel cells. (7) The stacked fuel cell according to claim 1, wherein ring walls are respectively raised from the ring-shaped metal member along the inner peripheral surface of the insulator, and the insulator and the ring-shaped metal member are connected to each other. A stacked fuel cell characterized by being joined by press-fitting and staking. (8) The stacked fuel cell according to claim 7, wherein the inner peripheral surface of the insulator has a concave cross section. (9) The stacked fuel cell according to claim 1, wherein at least a part of the insulator is provided with a wetting member whose surface becomes wet or flexible at high temperature, and both sides of the wetting member and the insulator are provided. A stacked fuel cell characterized in that a seal is formed between the ring-shaped metal member on the side. (10) The stacked fuel cell according to claim 1, wherein the ring-shaped metal member and the separator portion are connected by providing a rising or falling portion in each opposing portion. A stacked fuel cell characterized by: (11) The stacked fuel cell according to claim 1, wherein the insulator is composed of a composite member of a metal and an insulating ceramic. (12) The stacked fuel cell according to claim 1, wherein the ring-shaped metal member portion near the bonding interface between the insulator and the ring-shaped metal member has a coefficient of thermal expansion smaller than that of the metal. A stacked fuel cell is characterized by being constructed from a composite material. (13) The stacked fuel cell according to claim 1, wherein at least the insulator portion near the bonding interface between the insulator and the ring-shaped metal member is made of a composite material made of an insulating substance and a metal. A stacked fuel cell characterized by the following structure. (14) The stacked fuel cell according to claim 13,
A stacked fuel cell characterized in that the composite material layers are arranged in multiple stages and an insulating layer is interposed between adjacent composite material layers.