JPH07201353A - Fuel cell - Google Patents

Abstract

PURPOSE:To always provide a stable generating function by bringing surfaces opposed to each other of a member, relating to a constitution of sealing a manifold region, and a separator singly mechanically into contact air-tightly sealed, so as to improve reliability of gas seal performance in a manifold part. CONSTITUTION:A fuel cell comprises a layer-built type fuel cell main unit formed by interposing a separator 5 for forming a fuel system gas flow path 7c and oxidant system gas flow path 7d between unit fuel cells 3, 3' and a manifold region air-tightly communicating with both the gas flow paths respectively through a hole 8 piercing the separator 5 in the thickness direction. This manifold region is constituted by arranging a plurality of ring-shaped members (example: concurrently using seal ring 10), containing at least electric insulating manifold ring 6, with mutual lamination direction surfaces putting into contact with each other and also by bringing surfaces opposed to each other of the ring-shaped member and the separator 5, corresponding to this ring-shaped member, mechanically into contact air-tightly sealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell in which unit fuel cells are laminated, and more particularly, to improve the reliability of gas sealing performance of a manifold portion, and to improve manufacturability and detachability of unit fuel cells. The present invention relates to a fuel cell.

[0002]

2. Description of the Related Art As is well known, in a fuel cell, the Gibbs free energy component of the difference between the chemical potential of a fuel gas and an oxidant gas and the chemical potential of a product of the reaction is directly converted into an electric energy. It is a system to convert to. A fuel cell that directly converts this chemical energy into electric energy sandwiches an electrolyte plate (electrolyte layer) made of, for example, molten carbonate,
A pair of electrodes (anode and cathode) are arranged on both main surface sides. Then, the oxidant gas and the fuel gas are separately supplied from both electrode sides, each gas is brought into contact with both electrodes, and the battery reaction is promoted by mediating the ion migration in the electrolyte plate, so that the ions in the electrolyte plate The basic configuration is to take the flow out of the battery and obtain it as an electromotive force.

However, the electromotive force obtained by the unit fuel cell is a low value which is less than 1 V at most. Therefore, when used as a high-output power generation system, the unit fuel cell area increases (for example,
1m x 1m) and multiple unit fuel cells (for example, several tens to one)
(About 00 pieces) is stacked in series to form a fuel cell stack, and by operating with the temperature of the electromotive section maintained at a high temperature of about 600 to 700 ° C, the added output of each unit cell is obtained. Has been taken.

Next, an example of a conventional fuel cell will be described with reference to the drawings. FIG. 16 is a perspective view showing a developed main structure of a fuel cell stack, and FIG. 17 is a cross-sectional view showing a main structure of the fuel cell stack taken along line AA.

An anode 2a is formed on both main surfaces of the electrolyte plate (layer) 1.
And between the unit fuel cells 3 having the cathode 2b,
Separator members 5a, 5 are provided via current collecting plates 4a, 4b, respectively.
A separator 5 formed by b and 5c is arranged. In addition, a manifold ring (for example, made of ceramic) 6 having electrical insulation is airtightly connected to a required separator 5 and is laminated.

Here, the separator members 5a, 5b, 5c are required to have workability, heat resistance, and corrosion resistance against an electrolyte.
It is generally made of stainless steel, and is normally partitioned by a separator 5a, one surface side of which is the fuel system gas flow path 7a (or oxidant system gas flow path 7b) of the first unit fuel cell 3 and the other surface side of which is Oxidant gas flow path 7b of the second unit fuel cell 3
(Or, the fuel system gas flow path 7a) is divided. The separator 5 also has a function as a fuel system gas channel 7c or an oxidant system gas channel 7d in the stacking direction, and a through hole 8 connected to the manifold ring 6 is provided in the thickness direction. Since the separators 5 should not be electrically short-circuited by mechanical contact, the manifold ring 6 mechanically connected to the separators 5 is required to have electrical insulation.

Further, it is important that the fuel system gas channel 7c and the oxidant system gas channel 7d maintain a sufficient space for supplying and discharging the corresponding gas. That is, the supply of the fuel-based gas and the oxidant-based gas required for power generation is performed both in the stacking direction of the unit fuel cells 3 and in the in-plane direction of the unit fuel cells 3, and the manifold ring 6 and the surface are arranged in the stacking direction. The gas is supplied inward by gas channels 7c and 7d formed by the separator 5. Then, between the manifold ring 6 and the separator 5,
Since it is required to maintain the gas sealability, those joints are generally joined and sealed using a brazing material 9a or a high temperature adhesive.

[0008]

As described above, in the fuel cell stack (stacked fuel cell), the manifold ring 6 is generally made of ceramic and the separator members 5a, 5b, 5c are made of metal. Therefore, there is a large difference in the coefficient of thermal expansion with respect to the temperature. Therefore,
In the process of functioning as a fuel cell, that is, in the temperature raising / lowering process during power generation, thermal stress is generated in the manifold ring 6, the separator 5, and the brazing material 9a and a bonding agent such as an adhesive. Here, when the thermal stress generated is large, the brazing material
9a and adhesives are easily peeled off, the manifold ring 6 is easily broken, and even if moderate thermal stress is generated, damage caused by thermal stress due to repeated temperature rising / falling processes is accumulated.
This may lead to peeling of the brazing material 9a or adhesive, breakage of the manifold ring 6, and deterioration of gas sealability in the manifold region.

When the gas sealing performance deteriorates in this way,
The leakage of the fuel gas and the oxidant gas, the deterioration of the cell performance due to the inflow of the purge gas, and the fear that the combustion may occur due to the mixing of the fuel gas and the oxidant gas occur, which can be said to be a problem in terms of safety and reliability. Furthermore, in assembling and manufacturing the fuel cell, since the laminated separator 5 is joined via the manifold ring 6, the process of laminating and arranging the unit fuel cells 3, 3'and the separator 5 becomes complicated. . In addition, if a problem occurs in a part of the unit fuel cells 3, 3'after stacking them, it is difficult to replace and attach them, and there is a problem in productivity.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a fuel cell which improves reliability of gas sealing performance of a manifold portion and always exhibits a stable power generation function.

[0011]

In order to achieve the above object, in the fuel cell of the present invention, a unit fuel cell having a structure in which an electrolyte layer is sandwiched by a pair of electrode layers from both main surface sides is used. A fuel cell gas passage on one main surface side, and a laminated fuel cell main body formed by interposing a separator for forming an oxidant gas passage on the other main surface side, and the separator penetrates in the thickness direction. A fuel cell and a manifold region that is in air-tight communication with the fuel-based gas flow passage and the oxidant-based gas flow passage, respectively, and the manifold region includes at least a plurality of electrically insulating manifold rings. The ring-shaped members are arranged such that their surfaces in the stacking direction are in contact with each other, and the surfaces of the ring-shaped members and the separators corresponding to the ring-shaped members are mechanically brought into contact with each other so that the air-conditioning It is characterized by being configured sealed with.

Further, it is characterized in that a manifold region tightening means is provided for generating a tightening force for airtightly contacting mutually facing surfaces of the ring-shaped member and the separator.

Further, the ring-shaped member is characterized by being provided with a metal seal ring having a restoring property to the tightening force. Further, the ring-shaped member is provided with a spacer having rigidity with respect to the tightening force.

Further, an electromotive portion for generating electric power based on the fuel gas and the oxidant gas supplied to the fuel gas passage and the oxidant gas passage, respectively, and the electromotive portion is used as the unit. An electromotive section clamping means for generating a clamping force for clamping in the stacking direction of the fuel cell is provided, and the clamping force of the manifold area clamping means is set to be larger than the clamping force of the electromotive section clamping means.

Further, the present invention is characterized in that the intermediate region header is formed so as to be branched from the manifold region and connects the manifold regions in the stacking direction of the unit fuel cells.

[0016]

In the fuel cell according to the present invention, the members that are involved in the sealing structure of the manifold region and the surfaces of the separator that face each other are simply mechanically contacted and hermetically sealed and then bonded or Since the manifold area is gas-sealed without joining, thermal stress caused by the difference in thermal expansion between members is eliminated. Therefore, in the temperature raising / lowering process during the operation of the fuel cell, the occurrence of breakage (damage) of the manifold ring or the like is eliminated and a highly reliable gas seal is secured.

In particular, when a spacer having sufficient rigidity with respect to the tightening force is arranged in the gas passage of the tightening portion for hermetically sealing the manifold area, at least one of the plurality of seal members is tightened in the tightening direction. On the other hand, when a deformable material is used, it is possible to secure more reliable gas sealing performance in the manifold area.

Moreover, since the airtight sealing is performed only by mechanical contact in the manifold area, and the separator is not bonded or joined to the sealing member including the manifold ring, the process of stacking the unit fuel cells and the separator can be facilitated, and When a problem occurs in a part of the unit fuel cells after the stacking and arrangement, parts such as the unit fuel cell and the separator member can be easily attached / detached and replaced.

Further, the tightening means for hermetically sealing the manifold area and the means for tightening the electromotive section of the unit fuel cell are separately configured, and the tightening force of the manifold area is controlled by the electromotive section of the unit fuel cell. By setting the strength higher (stronger) than the tightening force, it is possible to secure highly reliable gas sealing performance in the manifold area.

Further, the characteristic part of the present invention having the above-mentioned action is to install an intermediate gas header in the gas flow path in the stacking direction,
It is similarly applicable to a fuel cell of a type configured to supply a required gas to each unit fuel cell through the intermediate gas header.

[0021]

EXAMPLES Examples of the fuel cell of the present invention will be described below with reference to FIGS. 1 to 15. (First Embodiment) FIG. 1 is a sectional view showing the structure of a main part of a fuel cell according to the first embodiment of the present invention, and FIGS. 2 to 4 are also used for the fuel cell according to the first embodiment of the present invention. It is a perspective view which shows the structural member of a principal part.

The fuel cell according to this embodiment has an electrolyte plate 1
The unit fuel cells 3 and 3 ′ are arranged such that the (electrolyte layer) is sandwiched between a pair of electrodes, that is, the anode 2 a and the cathode 2 b from both main surface sides thereof. A separator 5 composed of separator members 5a, 5b and 5c is arranged between the unit fuel cells 3 and 3'through current collecting plates 4a and 4b, respectively. In order to form a required gas channel between the plurality of separators 5, a space between the separators 5 is formed by stacking an electrically insulating ceramic manifold ring 6 and a metal ring member (seal ring) 10. Are configured to be connected airtightly.

That is, the manifold ring 6 and the seal ring 10 are laminated and interposed between the separators 5,
It functions as a fuel gas channel or an oxidant gas channel.

FIG. 2 is a perspective view showing a concrete example of the structure of the manifold ring 6. The manifold ring 6 is made of, for example, ceramics such as alumina, zirconia, magnesia, aluminum nitride, and silicon nitride, has an outer diameter of about 100 to 200 mm, a thickness of about 3 to 8 mm, and a unit fuel cell. 3 has a region of about 1 m × 1 m.

In the structure described above, the metallic separator members 5a, 5b, 5c are made of stainless steel in view of requirements such as workability, heat resistance, and corrosion resistance against electrolytes. The metallic separator members 5a, 5b, 5c are provided with holes 8 penetrating in the stacking direction to form gas channels in the stacking direction, and the separator member 5a is used as a partition plate to form a unit fuel with the separator member 5b. The fuel system gas channel 7c (or the oxidant system gas channel 7d) to the cell 3 side and the oxidant system gas channel 7d (or the fuel system gas channel 7c) to the unit fuel cell 3 side are formed between the separator member 5c. Is forming.

Further, in order to sufficiently secure the fuel system gas channel 7c or the oxidant system gas flow path 7d formed by the separator members 5a, 5b and 5c, respectively, and to ensure the planarity of the separator 5 in the manifold region. In order to obtain good contact with the manifold ring 6 and the seal ring 10, for example, a spacer having a configuration shown in perspective in FIG.
11 is built in the separator 5.

As will be described later, the material of the spacer 11 is made of a material having sufficient rigidity to withstand tightening, and specifically, stainless steel, Ni-based or Cr-based heat-resistant metal. The spacer can also be formed of ceramics such as alumina, zirconia, magnesia, or the like.

On the other hand, since the seal ring 10 is required to be deformable with respect to tightening, it is made of metal such as stainless steel, and can be deformed and restored in response to tightening and unfastening ( The member has a deformable and restorable property, for example, a spring 10a. That is, the seal ring 10
Fuel system gas channel 7c for unit fuel cell 3, 3 '
When the manifold region that seals and connects the gaps or between the oxidant gas channels 7d is tightened with a required force, it is deformed or restored by the tightening force.

FIG. 4 is an exploded perspective view showing the seal ring 10 and the spring 10a having a deformable and restorative property. In the present invention, the seal ring 10 having the structure including the separator 5 surface functioning as a gas channel in the stacking direction, both end surfaces of the manifold ring 6, and the spring 10a.
The surface and the surface of the separator 5 are laminated in the above-mentioned order, and the surfaces of the surfaces are in contact with each other. Then, these members are tightened and sealed in the stacking direction by a required tightening force to form an airtight manifold region.

That is, the unit fuel cells 3, 3 ′ are arranged between the unit fuel cells 3, 3 ′ through the current collector plates 4 a, 4 b, and in-plane to the electrodes 2 a (2 b) of the unit fuel cells 3, 3 ′. Direction of the gas channel 7c (7d) in which the spacer 11 is formed inside is formed so as to surround the through hole 8 forming the gas flow path in the stacking direction, and the manifold ring 6 side and deformation / restorability The surfaces of the seal rings 10 containing the members (springs) 10a having the above are contacted in a laminated manner, and by tightening this area in the laminating direction, good contact is maintained, thus adopting a hermetically sealed structure. There is.

In this configuration example, a part of the gas channel in the stacking direction is formed by the metal seal ring 10 having the spring 10a built therein. Therefore, even when the electrolyte plate 1 undergoes creep deformation during power generation to reduce its thickness and the distance between the separators 5 decreases, the change in the distance changes due to the metal seal ring 10 containing the spring 10a. Absorbed by the restorable deformation of.

In such a manifold area structure, the metal separator 5 and the metal seal ring 10 having a difference in thermal expansion and the ceramic manifold ring 6 are combined. However, since these merely adopt a configuration in which they are in mechanical contact with each other, the occurrence of thermal stress due to the difference in thermal expansion due to temperature rise / fall during power generation of the fuel cell is eliminated. . Therefore, destruction of the manifold ring 6 due to thermal stress, which has been a problem in the past, can be avoided, and high reliability of gas sealing performance can be maintained.

Further, since the structure of the manifold region is a combination by mechanical contact, not only the assembly and manufacturing are simplified, but also the unit fuel cells 3,
It is easy to replace the components of 3'and bring many advantages in terms of productivity and maintenance.

In the structure of the laminated fuel cell in which the unit fuel cells 3 and 3'are arranged in layers, the metal seal ring 10 and the separator 5 are brazed, welded, and heated at a high temperature before the lamination arrangement. It may be bonded in advance by adhesion with an adhesive or the like. In this case, the manufacturing process is facilitated and the gas sealability can be improved. Also, regarding the spacer 11 built in the separator 5,
The opposing separator members 5a, 5b, 5c may be preliminarily joined by brazing, welding, bonding with a high temperature adhesive, or the like prior to stacking. In this case, the manufacturing process becomes easy.

Furthermore, the solid members constituting the manifold region, that is, the contact surface or the peripheral surface of the separator 5, the ceramic manifold ring 6, and the seal ring 11, are usually used as a release agent such as boron nitride or alumina. By interposing ceramic fine particles such as, or low melting point glass fine particles, good gas sealing properties can be maintained for a long period of time. Further, since the seizure of the members can be prevented and the disassembling can be facilitated, the disassembling work when replacing the defective unit fuel cell among the unit fuel cells formed by stacking a plurality of members can be easily performed.

FIG. 5 is a perspective view showing another structural example of the spacer 11 incorporated in the separator 5 according to the modification of the first embodiment of the present invention. In this modification, in the fuel cell having the same configuration as that of the first embodiment, another method for ensuring the flatness of the separator 5 in the manifold region and obtaining good contact with the manifold ring 6 and the seal ring 10 is provided. It relates to a configuration example.

That is, the spacer 11 according to this modification.
Has upper and lower surfaces formed into flat surfaces as shown in FIG. In this way, when the upper and lower surfaces of the spacer 11 are configured as flat surfaces, the flat surface of the separator 5 is maintained, so that the manifold area is configured and the solid members that are in contact with each other are kept in good contact during tightening. Sagging contributes to the formation of airtight seals and bonds.

(Second Embodiment) FIG. 6 is a cross-sectional view showing the structure of the main part of a fuel cell according to the second embodiment of the present invention. In this configuration example, in comparison with the configuration example shown in FIG. 1, the thickness of the ceramic manifold ring 6 is smaller than that of the first embodiment, and the metal thick plate rings 12, 12 are formed. ′ Is laminated on both sides of the manifold ring 6 to form a predetermined gas channel. The other structure is basically the same as that of the first embodiment.

In the structure of the second embodiment, the gas seal structure in the manifold area is composed of the separator member 5b, the seal ring 10, the thick plate ring 12, the manifold ring 6, the thick plate ring 12 'and the separator member 5c. By stacking, the surfaces adjacent to each other are brought into contact with each other and tightened in the stacking direction. Here, since the thick plate rings 12 and 12 'can maintain the flatness of the upper and lower surfaces higher than those of the thin separator members 5b and 5c and the seal ring 10, the contact with the manifold ring 6 is further improved. It becomes possible to do.

Also in this configuration example, since the solid members forming the manifold region are simply in mechanical contact with each other, a difference in thermal expansion is caused by temperature rise / fall during power generation of the fuel cell. The generation of thermal stress is eliminated. Therefore, destruction of the manifold ring 6 due to thermal stress, which has been a problem in the past, can be avoided,
High gas seal reliability is maintained. Furthermore, since the structure of the manifold area is a combination by mechanical contact, assembly and manufacturing are simplified, and
It is possible to easily perform disassembly work when replacing a defective unit fuel cell among a plurality of unit fuel cells configured by stacking.

In assembly and manufacturing, prior to the laminated arrangement of the separator member 5b, the seal ring 10 and the thick plate ring 12, and the thick plate ring 12 'and the separator member 5c,
Assembling workability and gas sealability are improved by preliminarily joining them by brazing, welding, or bonding with a high-temperature adhesive.

(Third Embodiment) FIG. 7 is a cross-sectional view showing the structure of the main part of a fuel cell according to the third embodiment of the present invention. In this configuration example, in contrast to the configuration example shown in FIG. 6, the ceramic manifold ring 6 is configured such that the outer peripheral surface is thicker than the inner peripheral surface. One of the surfaces 12 and 12 'is characterized in that it is formed in a tapered shape in which the outer peripheral surface is thinner than the inner peripheral surface. The faces of the thick plate rings 12 and 12 'are laminated on both sides of the manifold ring 6 to form a desired gas channel.

The other structure is basically the same as that of the embodiment described above. Also in the structure of the stacked fuel cell shown in FIG. 7, the gas seal structure in the manifold region has a separator member 5b, a seal ring 10, a thick plate ring 12, a manifold ring 6, a thick plate ring 12 'and a separator member. By stacking 5c, adjacent surfaces are brought into contact with each other and tightened in the stacking direction.

Further, in the case of this configuration example, the manifold ring 6 is used when the temperature of the fuel cell is raised or lowered during power generation.
Since there is a difference in thermal expansion between the thick plate rings 12 and 12 ', thermal expansion causes deformation in the direction of increasing the radius. And
This deformation is larger for the metal plate rings 12 and 12 ',
Since these contact surfaces are pushed from the inner peripheral side to the outer peripheral side, mutual contact becomes more solid and the gas sealability is improved.

In addition, since the solid members forming the manifold area are merely in mechanical contact with each other, the thermal expansion difference is caused by the temperature change during power generation of the fuel cell. Generation of thermal stress will be eliminated. Therefore, destruction of the manifold ring 6 due to thermal stress, which has been a problem in the past, can be avoided, and high reliability of the gas seal can be maintained. Further, since the structure of the manifold area is a combination by mechanical contact, the assembly and manufacturing are simplified, and the defective unit fuel cell among the unit fuel cells formed by stacking a plurality of units is replaced. The disassembly work can be done easily.

Before assembly and manufacturing, the separator member 5b, the seal ring 10 and the thick plate ring 12, and the thick plate ring 12 'and the separator member 5c are stacked and arranged.
If they are previously joined by brazing, welding, bonding with a high-temperature adhesive, etc., the assembly workability and the gas sealability can be improved.

(Fourth Embodiment) FIG. 8 is a cross-sectional view showing the structure of the main part of a fuel cell of a fourth embodiment of the present invention. In this configuration example, in contrast to the configuration example shown in FIG. 7, the so-called manifold region is made opposite to the ceramic manifold ring 6 in which the outer peripheral surface is thicker than the inner peripheral surface. Tapered metal plate ring with a thinner outer peripheral surface than the inner peripheral surface 1
The feature is that only 2 and 12 'are used as the solid member (the seal ring 10 is removed). The surfaces of the thick plate rings 12 and 12 'are laminated on both sides of the manifold ring 6 to form a desired gas channel. The other structure is the same as that of the embodiment described above.

Also in the structure of the laminated fuel cell shown in FIG. 8, the gas seal structure in the manifold region has a separator member 5b, a thick plate ring 12, a manifold ring 6, a thick plate ring 12 'and a separator member 5c. By laminating, the surfaces adjacent to each other are brought into contact with each other and tightened in the laminating direction.

In the case of this configuration example, the creep deformation of the electrolyte plate 1 is absorbed by the deformation of the separator members 5a, 5b, 5c. Further, when the fuel cell is heated or cooled during power generation, the manifold ring 6 and the thick plate rings 12 and 12 'are deformed in the direction of increasing the radius due to thermal expansion.
Due to the difference in linear thermal expansion, this deformation is caused by a metal plate ring.
12, 12 'are larger, and their contact surfaces are pushed from the inner peripheral side to the outer peripheral side, so that mutual contact becomes more solid and the gas sealing performance is improved.

In addition, since the solid members forming the manifold region are merely in mechanical contact with each other, the difference in thermal expansion caused by the temperature change during power generation of the fuel cell is also caused. The generation of thermal stress is eliminated. Therefore, destruction of the manifold ring 6 due to thermal stress, which has been a problem in the past, can be avoided, and high reliability of the gas seal can be maintained. Further, since the structure of the manifold area is a combination by mechanical contact, the assembly and manufacturing are simplified, and the defective unit fuel cell among the unit fuel cells formed by stacking a plurality of units is replaced. The disassembly work can be done easily.

In the assembly / manufacturing, prior to the laminated arrangement of the separator member 5b and the thick plate ring 12 and between the thick plate ring 12 'and the separator member 5c, they are previously joined by brazing, welding, bonding with a high temperature adhesive, etc. If so, the assembling workability and the gas sealing property can be improved.

(Fifth Embodiment) FIG. 9 is a sectional view showing the structure of a main part of a fuel cell according to a fifth embodiment of the present invention. Figure 9
In the laminated fuel cell main body 13, a separator is provided between unit fuel cells having a structure in which an electrolyte plate is sandwiched between anode electrodes and cathode electrodes from both main surface sides thereof, with a collector plate interposed therebetween. It is arranged.

Here, the laminated fuel cell main body portion 13 discharges the gas supply manifold region 14 for supplying the required fuel system gas and oxidant system gas to the unit fuel cell, and the fuel system gas and the oxidant system gas. The gas discharge manifold region 15 and the electromotive section 16 are roughly classified. Airtight bellows
17a, 17b, 17c are arranged above the laminated fuel cell main body 13, and gas supply / exhaust ports 18a, 18b, 18c are provided.
Depending on the pressure of the gas supplied and exhausted from the electromotive unit 16,
The gas supply manifold region 14 and the gas discharge manifold region 15 have a function of tightening each in the stacking direction. Further, the lower tightening plate 19a and the upper tightening plate 19b are provided, and the laminated fuel cell main body 13 and the airtight bellows 17a, 17b, 17c are tightening rods for fixing the lower tightening plate 19a and the upper tightening plate 19b. It is fixed with a predetermined positional relationship by the tightening force of 20a, 20b.

In this structure, the airtight bellows 17a,
A gas having a pressure higher than that of the ambient gas in the enclosure (housing) in which the laminated fuel cell main body 13 and the like are housed is supplied to 17b and 17c. Due to the pressure of this high-pressure gas, a compressive force acts on the laminated fuel cell main body 13, electrical contact and gas seal are secured in the electromotive portion of the unit fuel cell, and gas seals are secured in the manifold regions 14 and 15. It
Then, by making the supply pressure of the high-pressure gas to the airtight bellows 17a, 17b, 17c different, it is possible to appropriately control the tightening force of the electromotive section, the tightening force of the manifold regions 14, 15, and the like. This control allows the contact surface pressure of the electromotive section and the contact surface pressures of the manifold regions 14 and 15 to be controlled independently to each other in an optimal state even in the operation of the fuel cell, corresponding to the operating conditions. It means that you can do it.

By making the contact surface pressure of the manifold region higher than the contact surface pressure of the electromotive portion, the sealing performance of the manifold region can be improved. FIG. 10 relates to a modification of the fifth embodiment of the present invention and is a cross-sectional view showing the configuration of the main part of the fuel cell.

In this configuration example, the laminated fuel cell main body 13 and the airtight bellows 17a, 17b, 17c have a lower tightening plate 19a and an upper tightening plate 19b, and a tightening rod 2
When tightening and fixing by the 0a and 20b, the insertion positions of the tightening rods 20a and 20b are set in the manifold regions 14 and 15, and the fixing positions are maintained and fixed. When this structure is adopted, it can be made compact as compared with the fifth embodiment shown in FIG. Note that FIG.
In the figure, 21 is an envelope (housing), and 22 is a fuel cell support.

FIG. 11 is a cross-sectional view showing the structure of the main part of the fuel cell according to a modification of the fifth embodiment of the present invention. In this configuration example, the airtight bellows 17a, 17b,
Instead of using the 17c, the upper tightening plates 23a, 2a are provided for each of the stacked fuel cell main body 13 and the manifold regions 14, 15.
While placing 3b and 23c, upper leaf springs 24a, 24b and 24c
And lower leaf springs 24a ', 24b', 24c ', and tightening rods 25a, 25b, 25c in the stacking direction. Even in such a configuration, by appropriately setting the tightening force, the contact surface pressure of the electromotive section and the contact surface pressure of the manifold regions 14 and 15 can be independently and appropriately controlled. Further, in this case, since the relatively expensive airtight bellows 17a, 17b, 17c can be omitted, cost reduction and downsizing can be achieved.

In this structure, as described above, the contact surface pressures of the manifold regions 14 and 15 and the electromotive section 16 are individually controlled by selectively setting the tightening force of the airtight bellows 17a, 17b, 17c and 17d. ing. Therefore, by setting the contact surface pressure of the manifold regions 14 and 15 higher than the contact surface pressure of the electromotive section 16, it is possible to maintain good gas sealing in the manifold region.

Here, an example in which the tightening force of the manifold regions 14 and 15 is set to be larger than the tightening force of the electromotive section 16 to improve the gas seal in the manifold region has been described. Depending on the case, conversely, the tightening of the electromotive section 16 may be set to be larger than or equal to the tightening force of the force manifold regions 14 and 15.

(Sixth Embodiment) Generally, in a fuel cell, if the number of unit fuel cells stacked increases, it becomes difficult to supply or discharge gas along the stacking direction. A configuration in which the intermediate gas header is arranged at the position is adopted.

12 to 15 show the essential parts of a structural example relating to a fuel cell provided with such an intermediate gas header. First, FIGS. 12 (a) and 12 (b) are a schematic top view and a side view of the intermediate gas header, and FIG. 13 is a cross-sectional view showing the intermediate gas header in cross section. Further, FIG. 14 is a side view of a fuel cell equipped with an intermediate gas header, and FIG.
14A and 14B respectively show top views taken along the line AA.

In FIGS. 12 (a) and 12 (b), 26 is an intermediate gas header, which is a fuel gas supply passage (or fuel gas discharge passage) 26a forming a part of the manifold area 14 (15) and an oxidant gas supply. The fuel gas supply pipe (or fuel gas discharge pipe) 31a, the oxidant gas supply pipe (or oxidant gas discharge pipe) 31a, and the supply passages or discharge passages 26a and 26b are provided. It has a structure branched from 31b. And the intermediate gas header 26
13, a box-shaped internal space is airtightly divided by a partition plate 27c to form a fuel gas supply port (or fuel gas discharge port) 27a, an oxidant gas supply port (or oxidant gas) as shown in FIG. 27b is formed.

Then, their supply port or discharge port 27
a and 27b are respectively connected to the manifold regions of the unit fuel cell stack cells 28 arranged above and below to form the required manifold regions 14 and 15, and the fuel gas supply pipe (or fuel gas discharge pipe) 31a and the oxidation The agent gas supply pipe (or oxidant gas discharge pipe) 31b is connected to the fuel gas supply pipe (or fuel gas discharge pipe) 31a of the other intermediate gas header 26 via the expansion-contraction type connection pipe 29 to supply gas. Tube 31a
From (31b), gas supply path 26a (26b), manifold area
Gas is supplied to each unit fuel cell via 14,15.

FIG. 14 shows a schematic overall structure of a fuel cell provided with the intermediate gas header 26. In this fuel cell, an intermediate gas header 26 and an intermediate spacer 30 are interposed between stacked cells 28 formed by stacking a plurality of unit fuel cells, and the cells are positioned and stacked. Further, the airtight bellows 17a, 17b, 17c, 17d are arranged on the upper surface side in the stacking direction, and the manifold plates 14, 15 and the electromotive section 16 are arranged in the stacking direction by the tightening plates 19a, 19b and the tightening rods 20a, 20b. Tightened, fixed, and sealed. Here, each manifold area 14 and 15 and the electromotive section 16
The degree of compression is appropriately adjusted by the airtight bellows 17a, 17b, 17c, 17d. Also, the intermediate spacer
As shown in FIG. 15, reference numeral 30 denotes an intermediate gas header 26 which is formed to have an outer size of the electromotive section 16 of the unit fuel cell laminated cell 28 or a size larger than that, and which forms a part of the manifold regions 14 and 15.
And are spaced apart from. The intermediate spacer 30 is
In order to electrically connect the unit fuel cell laminated cells 28, they are made of an electronically conductive material.

In the fuel cell having the above structure, the envelope 21
Fuel gas and oxidant gas supplied from the outside enter the manifold region of the unit fuel cell stack cell 28 via each intermediate gas header 26. After that, after being supplied to a so-called channel portion and undergoing a cell reaction, the fuel gas and the oxidant gas pass through the exhaust manifold region, gather at the intermediate gas header 26, and are exhausted to the outside of the envelope 21 through the gas exhaust pipes 27a and 27b. It

In this structure, as described above, the contact surface pressures of the manifold regions 14 and 15 and the electromotive section 16 are individually controlled by selectively setting the tightening force of the airtight bellows 17a, 17b, 17c and 17d. ing. Therefore, by setting the contact surface pressure of the manifold regions 14 and 15 higher than the contact surface pressure of the electromotive section 16, it is possible to maintain good gas sealing of the manifold section.

In addition, in the fuel cell having the above structure, when each member such as the electrolyte plate forming the unit fuel cell is deformed by creep or the like and the overall height in the vertical direction is reduced, the reduced amount is installed in the vertical direction. The contracted expansion and contraction connecting tube 29 can be absorbed by contracting, and in the manifold regions 14 and 15 and the electromotive section 16,
It can be absorbed by the expansion of the airtight bellows 17a, 17b, 17c, 17d.

Here, the tightening force of the manifold regions 14 and 15 is set to be larger than the tightening force of the electromotive section 16 to improve the gas sealing in the manifold region. However, for example, the stacked state of the fuel cell is described. Depending on the case, conversely, the tightening of the electromotive section 16 may be set to be larger than or equal to the tightening force of the force manifold regions 14 and 15.

The fuel cell according to the sixth embodiment is not limited to the above-mentioned constitution, but can be variously modified and implemented without departing from the spirit of the invention. For example,
On one side of the main body of the intermediate gas header 26, a fuel gas supply pipe
31a and the oxidant gas discharge pipe 31b are installed, and the oxidant gas supply pipe 31b and the fuel gas supply pipe 31a are installed on the other (opposite side) sides, respectively, so that the fuel gas and the oxidant gas flow in opposite directions. May be configured.

[0070]

As described above, in the fuel cell according to the present invention, it is possible to prevent the destruction of the manifold area due to the thermal stress, while improving the reliability of the gas seal in the manifold area. In other words, the influence of thermal stress generated during the assembly manufacturing process or the temperature rising / falling process during operation is greatly reduced and avoided, and the destruction of the manifold ring, which has a large impact on the reliability or safety of the fuel cell, is avoided. Therefore, the manifold area always holds a reliable gas seal and exhibits a stable function. In terms of manufacturing, the replaceability of the constituent members of the unit fuel cell is also good, and it can be said that this will greatly contribute to the improvement of yield and productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a main part of a fuel cell according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration of a manifold ring used for forming a manifold region of the fuel cell according to the first embodiment of the present invention.

FIG. 3 is a perspective view showing the structure of a spacer incorporated in the separator of the fuel cell according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view showing a configuration of a seal ring used for forming a manifold region of the fuel cell according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing another configuration of a spacer incorporated in the separator of the fuel cell according to the modification of the first embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a configuration of a main part of a fuel cell according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a configuration of a main part of a fuel cell according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a configuration of a main part of a fuel cell according to a fourth embodiment of the present invention.

FIG. 9 is a cross-sectional view showing the structure of a main part of a fuel cell according to a fifth embodiment of the present invention.

FIG. 10 is a cross-sectional view showing the configuration of the main parts of a fuel cell according to a modification of the fifth embodiment of the present invention.

FIG. 11 is a cross-sectional view showing the configuration of the main parts of a fuel cell according to a modification of the fifth embodiment of the present invention.

12A and 12B show a configuration of a main part of an intermediate gas header included in a fuel cell according to a sixth embodiment of the present invention, wherein FIG. 12A is a plan view and FIG. 12B is a side view.

FIG. 13 is a sectional view of an intermediate gas header included in a fuel cell according to a sixth embodiment of the present invention.

FIG. 14 is a schematic vertical sectional view of a fuel cell according to a sixth embodiment of the present invention.

FIG. 15 is a schematic cross-sectional view of a fuel cell according to a sixth embodiment of the present invention.

FIG. 16 is an exploded perspective view showing a configuration of a main part of a conventional stacked fuel cell.

FIG. 17 is a cross-sectional view showing the configuration of a main part of a conventional fuel cell.

[Explanation of symbols]

1 ... Electrolyte plate (electrolyte layer) 2a ... Anode 2b ... Cathode 3, 3 '... Unit fuel cell 4a, 4b ... Current collector plate 5 ... Separator 5a, 5b, 5c ... Separator member 6 ... Manifold ring 7c, 7d ... Gas channel 8 ... Through hole 9a ... Brazing material 10 ... Seal ring 10a ... Spring 11 ... Spacer 12, 12 '... Thick plate ring 13 ... Stacked fuel cell main body 14, 15 ... Manifold region 16 ... Electromotive parts 17a, 17b, 17c … Airtight bellows 18a, 18b, 18c… Gas supply / exhaust ports of airtight bellows 19a, 19b, 23a, 23b, 23c… Tightening plates 20a, 20b, 25a, 25b, 25c, 25d, 25e… Tightening rods 21… Enclosure 22 ... Supports 24a, 24b, 24c ... Upper springs 24a ', 24b', 24c '
… Lower spring 26… Intermediate gas header 27a… Fuel gas supply / exhaust port 27b… Oxidant gas supply /
Exhaust port 28 Unit battery stack cell 29… Expandable connection pipe 30… Intermediate spacer 31a… Fuel gas supply / exhaust pipe 31b… Oxidant gas supply /
Discharge pipe

Claims (7)

[Claims] 1. A fuel system gas flow path is provided on one main surface side of the unit fuel cell and a fuel gas flow path is provided on the other main surface side between unit fuel cells having a structure in which an electrolyte layer is sandwiched between a pair of electrode layers from both main surface sides. A laminated fuel cell main body having a separator for forming an agent-based gas flow channel, and the fuel-based gas flow channel and the oxidant-based gas flow channel through holes penetrating in the thickness direction of the separator. In the fuel cell, each of the plurality of ring-shaped members including at least an electrically insulating manifold ring is arranged in contact with each other in a stacking direction surface. At the same time, the fuel cell is characterized in that the ring-shaped member and the separator corresponding to the ring-shaped member are mechanically brought into contact with each other to hermetically seal the surfaces. 2. The fuel cell according to claim 1, further comprising a manifold region tightening means for generating a tightening force for airtightly contacting mutually facing surfaces of the ring-shaped member and the separator. . 3. The fuel cell according to claim 2, wherein the ring-shaped member is provided with a metal seal ring having a restoring property to the tightening force. 4. The fuel cell according to claim 2, wherein the ring-shaped member includes a spacer having rigidity with respect to the tightening force. 5. A fuel system gas flow path is provided on one main surface side of the unit fuel cell, and a fuel system gas flow path is provided on the other main surface side between unit fuel cells having a structure in which an electrolyte layer is sandwiched between a pair of electrode layers from both main surface sides. A laminated fuel cell main body having a separator for forming an agent-based gas flow channel, and the fuel-based gas flow channel and the oxidant-based gas flow channel through holes penetrating in the thickness direction of the separator. In the fuel cell, each of which has a manifold region that communicates with each other in an airtight manner, and wherein the manifold region includes a seal member including at least an electrically insulating manifold ring and a spacer having rigidity with respect to a tightening force in a surface in a stacking direction with respect to each other. Are placed in contact with each other, and the tightening force for mechanically contacting the opposing surfaces of the seal member and the separator corresponding to the seal member to hermetically seal the surfaces is generated. A fuel cell, characterized in that the fuel cell is configured by providing a means for tightening a manifold region to be generated. 6. An electromotive unit for generating electric power based on the fuel gas and the oxidant gas supplied to the fuel gas passage and the oxidant gas passage, respectively, and the electromotive unit serving as the unit. An electromotive section tightening means for generating a tightening force for tightening in the stacking direction of the fuel cell, wherein the tightening force of the manifold area tightening means is set to be larger than the tightening force of the electromotive section tightening means. The fuel cell according to claim 2 or claim 5. 7. The intermediate header, which is formed so as to branch to the manifold region and connects between the manifold regions in the stacking direction of the unit fuel cells. The fuel cell according to claim 5.