JP2002184448A - Solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate assembly of a solid electrolyte fuel cell by preventing contact and short-circuit between reaction gas supply pipes. SOLUTION: Cells and separators 3 are stacked alternately and a fuel gas supply hole 27A and an oxidizer gas supply hole 27B in each separator 3 are arranged in a staggered fashion such that they are 90 deg. away fro each other in the circumferential direction. Fuel gas reaction pipes 30 branching from a fuel gas supply manifold 14 are arranged alternately on both sides in a staggered fashion and are connected via insulating connecting pipes 32 to a separator fuel gas supply pipe 31 connected to the fuel gas supply holes 27A. External threads at the ends of the fuel gas supply pipe 30 and the separator fuel gas supply pipe 31 are threadably engaged with the internal threads 32a of the connecting pipes 32. The oxidizer gas supply pipe 34 of an oxidizer gas supply manifold 15 is similarly connected via the connecting pipes 32 to a separator oxidizer gas supply pipe 35 connected to the oxidizer gas supply holes 27B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolyte fuel cell comprising, for example, a flat solid electrolyte, and more particularly to a solid electrolyte fuel cell comprising a sealless type in which power generation cells and separators are alternately stacked. .

[0002]

2. Description of the Related Art As an example of a conventional solid oxide fuel cell, there is a stack type in which power generation cells such as single cells and separators are alternately stacked. In this solid oxide fuel cell, a fuel gas and an oxidizing gas are used as reaction gases, and the positive electrode side and the negative electrode side of the solid electrolyte are sandwiched between separators, and the reaction gas flow paths formed on the positive electrode side and the negative electrode side of the separator, respectively. An oxidizing gas such as oxygen or air is supplied to one of the grooves, and a fuel gas such as hydrogen is supplied to the other to cause a reaction. In the solid oxide fuel cell, a hole is formed in the power generation cell and the separator at the center of the power generation cell as a reaction gas supply manifold for supplying the reaction gas to the concave groove which is the flow path of the reaction gas on both surfaces of the separator. Or
There is a configuration in which holes are formed outside the power generation cell and inside the separator, and these holes are connected to form a reaction gas supply manifold. However, in such a configuration, a seal structure must be provided inside the solid oxide fuel cell in order to prevent the reaction gas from leaking from each of the holes, which disadvantageously increases the manufacturing cost due to a complicated configuration. is there.

Another solid electrolyte fuel cell is disclosed in, for example, JP-A-3-129675. In this fuel cell, a reaction gas supply manifold is provided.
The reaction gas is distributed to the grooves on both sides of each separator by being fitted near the central axis of the stacked power generation cells and separators. However, such a configuration has a disadvantage that the manufacturing process is complicated and the manufacturing cost is increased because the configuration is complicated. As another stack type solid oxide fuel cell, there is a fuel cell in which a reaction gas supply manifold is provided outside the fuel cell, and a reaction gas is supplied to each separator via a reaction gas supply pipe.

[0004]

However, in the solid oxide fuel cell, in response to the demand for small size and light weight, separators having a small thickness are alternately stacked with power generation cells to reduce the stack volume of the fuel cell. In addition, when trying to obtain a high power output, since the dimensional difference between the thickness of the separator and the diameter of the reaction gas supply pipe becomes small, the reaction gas supply pipes stacked in the same direction come into contact with each other. . In this case, when the reaction gas supply manifold and the separator are connected via the reaction gas supply pipe at the time of assembling the solid oxide fuel cell, the hand of an operator becomes inaccessible and it becomes difficult to assemble by manual operation. There's a problem. In addition, since the reaction gas supply pipes are usually formed of a conductive metal material, if the reaction gas supply pipes adjacent to each other in the stacking direction come into contact with each other, the electrical insulation between the separators cannot be maintained, and the solid electrolyte fuel There is a problem that the power generation characteristics of the battery are impaired.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid oxide fuel cell capable of easily assembling by preventing contact between reaction gas supply pipes. It is another object of the present invention to provide a solid oxide fuel cell capable of ensuring electrical insulation between separators even when the size and thickness of the separator are reduced.

[0006]

In the solid oxide fuel cell according to the present invention, power generation cells and separators are alternately stacked, and each of the separators and the reaction gas supply manifold are connected by a reaction gas supply pipe. The solid oxide fuel cell is characterized in that the reaction gas supply pipes arranged in the stacking direction are arranged so as to be shifted from each other in a direction crossing the stacking direction. In the stacking direction of the separator, the reaction gas supply pipes are arranged so as to be shifted from each other in a direction intersecting the stacking direction. Thus, the reaction gas supply pipe can be easily connected, and the assemblability by manual operation or the like is improved. In particular, it is preferable that the reaction gas supply pipes are alternately arranged on both sides of the reaction gas supply manifold in the stacking direction and arranged in a staggered manner.

A solid oxide fuel cell according to the present invention is a solid oxide fuel cell comprising power generation cells and separators alternately stacked, and each of the separators and a reaction gas supply manifold connected by a reaction gas supply pipe. The battery is characterized in that at least a part of the reaction gas supply pipe is provided with an insulating pipe to ensure electrical insulation. Even if the reaction gas supply pipe oscillates or the like, the insulating pipe portions come into contact with each other, thereby maintaining electrical insulation between the reaction gas supply pipes and preventing an electrical short circuit. In addition, even in the longitudinal direction of the reaction gas supply pipe, insulation between the separator side and the reaction gas supply manifold can be secured.

In the solid oxide fuel cell according to the present invention, power generation cells and separators are alternately stacked,
In a solid oxide fuel cell in which each of the separators and the reaction gas supply manifold are connected by a reaction gas supply pipe, the reaction gas supply pipes arranged in the stacking direction are mutually offset in a direction intersecting the stacking direction. And at least a portion of the reaction gas supply pipe is provided with an insulating pipe to ensure electrical insulation. By shifting the position of the reaction gas supply pipe, a gap is created between adjacent reaction gas supply pipes in the stacking direction, making it easy to connect the reaction gas supply pipe between the separator and the reaction gas supply manifold, etc. Improves the assemblability.
In addition, even if the reaction gas supply pipe oscillates in the stacking direction, the insulating pipe portions come into contact with each other, thereby maintaining the electrical insulation between the reaction gas supply pipes and also preventing an electrical short circuit. Insulation between the separator and the reaction gas supply manifold can also be secured in the longitudinal direction of the reaction gas supply pipe.

Further, a female screw portion is formed in the insulating tube portion,
The reaction gas supply pipes on the separator side and the reaction gas supply manifold side may be screwed into the female screw part, and the thermal expansion coefficient of the reaction gas supply pipe may be set to be larger than that of the insulating pipe part. At a high power generation temperature, the reaction gas supply pipe expands more thermally, so that the adhesion to the insulating pipe part is improved, and gas leakage at the connection part is eliminated, so that a decrease in power generation efficiency can be prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid oxide fuel cell according to an embodiment of the present invention will be described below with reference to FIGS.
1 is a side view of the solid oxide fuel cell according to the embodiment, FIG. 2 is a plan view of the solid oxide fuel cell shown in FIG. 1,
3 is a vertical sectional view taken along the line AA of FIG. 2, showing the structure of the extraction electrode portion in FIG. 2, FIG. 4 is a sectional view showing a main part of the solid oxide fuel cell shown in FIG. 1, and FIG. FIG. 6 is an explanatory view showing the reaction gas supply manifold, and FIG. 7 is a partially enlarged view of FIG. 6 showing a connection portion between the reaction gas supply manifold and the fuel gas supply pipe cut away. The solid oxide fuel cell 1 according to the embodiment has, for example, a substantially columnar appearance as shown in FIGS.
For example, as a stack (laminated body) 4 in which a substantially disk-shaped single cell 2 and, for example, a substantially disk-shaped separator 3 in which a porous metal plate (current collector) is interposed in concave portions on both surfaces thereof are alternately stacked. It is configured. And single cells 2 stacked coaxially
A pair of fixing plates 6 and 7 having central holes 6a and 7a are provided on both sides of the stack 4 including the separator 3 and a plurality of studs at predetermined intervals along the outer periphery of the stack 4 between the fixing plates 6 and 7. Bolts 8 are fitted, and both ends of each stud bolt 8 are fastened with nuts 9 via flat washers, so that each unit cell 2, separator 3 and porous metal plate are fixed between fixed plates 6 and 7. , And is fixedly held in a pressed state in which it comes into close contact with the boss.

The central holes 6a, 7a of the fixing plates 6, 7 are provided.
And extraction electrodes 11, 12 extending coaxially with the central holes 6a, 7a from both ends of the stack 4 are provided. These extraction electrodes 11, 12 are composed of disk portions 11a, 12a and cylindrical portions 11b, 12b, and are provided with a cylindrical portion 11b. , 12b are formed in a substantially bellows shape by alternately forming ring-shaped slits from the inside and the outside in a direction substantially orthogonal to the axial direction, thereby providing a spring structure to the extraction electrodes 11, 12. Therefore, when a plurality of solid oxide fuel cells 1 are connected in series in the axial direction as one block, the difference in thermal expansion due to the temperature difference between the blocks when the solid oxide fuel cell 1 expands during operation can be absorbed. become. One side of the disk plates 11a and 12a of the extraction electrodes 11 and 12 is in direct contact with the end separator 3A of the stack 4, and the other opposite side is surrounded by an insulating sheet 5 such as a ceramic sheet. It is in contact with fixing plates 6 and 7. The cylindrical portions 11b and 12b of the extraction electrodes 11 and 12 having a spring structure extend from the center of the other one side of the disk portions 11a and 12a, and extend through the central holes 6a and 6 of the fixing plates 6 and 7.
7a is positioned substantially coaxially therethrough so as not to contact each other with a certain gap. Slits 6b, 7b are formed from the opposing side surfaces of the fixing plates 6, 7 in the direction of the central axis of the stack 4 (the direction of the central holes 6a, 7a). A fuel gas supply manifold 14 (reactive gas supply manifold) for distributing and supplying a fuel gas such as hydrogen to each of the separators 3 is provided in one of the pair of slits 6 b and 7 b arranged in the central axis direction.
Are fitted substantially parallel to the central axis of the. Similarly, an oxidizing gas supply manifold 15 (reactive gas supply manifold) for distributing and supplying an oxidizing gas such as oxygen or air to each separator 3 is fitted in the other pair of slits 6b and 7b. And these manifolds 14, 15
Both ends are fixed to the outside of the fixing plates 6 and 7 with nuts 16... Via flat washers.

Next, an example of the structure of each single cell 2 and separator 3 of the stack 4 will be described mainly with reference to FIGS. In FIG. 4, one single cell 2 is a disc-shaped solid electrolyte plate 1 made of an oxide solid electrolyte such as zirconia.
8, positive electrode (air electrode) 19 and negative electrode (fuel electrode) on both sides
20. The separator 3 has a disk shape made of stainless steel or the like, and has a surface 22 in the thickness direction.
A and the back surface 22B have substantially the same shape.
The fuel gas is supplied from the fuel gas supply manifold 14 to the A side, and the oxidizing gas supply manifold 1 is supplied to the back surface 22B side.
The oxidant gas is supplied from 5. The front surface 22A is pressed against the negative electrode 20 of the single cell 2, and the back surface 22B is pressed against the positive electrode 19.

The surface 2 of the separator 3 shown in FIGS. 4 and 5
2A, the inner peripheral surface 2 inside the annular outer peripheral surface 23A.
4A is recessed toward the back surface 22B from the outer peripheral surface 23A and fitted with a disc-shaped porous metal plate 25 to be flush with the outer peripheral surface 23A, and has a bottomed cylindrical shape at the center of the inner peripheral surface 24A. 26A are formed. The recess 26A has a surface 22A.
And a fuel gas supply hole 27A which is open to the outer wall surface 3a of the separator 3 through the inside of the separator 3. In the present embodiment, only one fuel gas supply hole 27A is formed on the outer wall surface 3a near the surface 22A of each separator 3, but a plurality of fuel gas supply holes may be provided.

A plurality of substantially spiral-shaped grooves 28A for fuel gas are formed at predetermined intervals on the surface of the inner peripheral surface 24A. One end of each of the concave grooves 28A communicates with the concave portion 26A, and the other end has an outer peripheral surface. Communicate with fuel gas discharge holes 29A. The plurality of fuel gas discharge holes 29A are formed at predetermined intervals so as to penetrate substantially in the radial direction, and the fuel gas flowing from the concave portion 26A to the inside of the concave groove 28A is formed on the outer wall surface 3 of the separator 3.
a can be discharged. The back surface 2 of the separator 3
2B has substantially the same configuration as the front surface 22A, and the rear surface 22B is provided with an oxidizing gas supply hole 27B instead of a fuel gas.
From the outer surface 3a through the plurality of grooves 28B for oxidizing gas and from the outer wall 3a through the oxidizing gas discharge holes 29B. The oxidizing gas supply hole 27B is provided, for example, one at a position opposed to the fuel gas supply hole 27A in the circumferential direction by, for example, 180 ° and shifted in the thickness direction. still,
The fuel gas supply passage 27A, the concave portion 26A, the concave groove 28A, the fuel gas discharge hole 29A, etc., which are the configuration of the fuel gas flow channel provided on the front surface 22A side, and the oxidizing gas flow channel configuration provided on the back surface 22B side. As shown in FIG. 4, the oxidizing gas supply hole 27B, the concave portion 26B, the concave groove 28B, the fuel gas discharge hole 29B, and the like are separated from each other on the front side and the back side in the thickness direction of the separator 3, and do not communicate with each other.

In the structure of the stack 4, the separators 3 are stacked with the front surface 22A and the back surface 22B facing in the same direction, and the fuel gas supply holes 27A on the front surface 22A side of the separator 3 and the back surface 22B The oxidizing gas supply hole 27B is provided 180 ° opposite to the oxidizing gas supply hole 27B. The gas supply holes 27B are held at a predetermined angle, for example, 90 ° from each other in the circumferential direction. In this way, the fuel gas supply holes 27A and the oxidizing gas supply holes 27B of each separator 3 are stacked in a zigzag pattern alternately shifted by 90 ° in the stacking direction. Also, as shown in FIGS. 1 and 2, the fuel gas supply manifold 14 is disposed in the circumferential direction of the separators 3 and 3 adjacent to each other in the stacking direction.
The middle of the fuel gas supply holes 27A, 27A separated by 0 ° (for example, 45 ° from each fuel gas supply manifold 14, 14)
Angle). Further, as shown in FIGS. 6 and 7, the fuel supply manifold 14 includes a plurality of gas supply pipes 30.
Are formed to be branched to the left and right sides and to be alternately shifted in the longitudinal direction. At the connection between the fuel gas supply manifold 14 and each fuel gas supply pipe 30, a throttle 33 for controlling the flow rate of the fuel gas is formed (see FIG. 7).

The fuel gas supply holes 27 of each separator 3
A is connected to each of the separator-side fuel gas supply pipes 31.
And the fuel gas supply pipe 30 are connected to the connection pipe 3 having a larger outer diameter.
2 are connected. The connection tube 32 is formed of an insulating material, for example, ceramic, has an outer shape of a quadrangular prism, and has an internal through hole formed as a female screw portion 32a. The connecting portions of the fuel gas supply pipe 30 and the separator-side fuel gas supply pipe 31 are externally threaded to form externally threaded portions 30a, 31a. These externally threaded portions 30a, 31a are formed.
Are connected to each other by screwing into the female screw portion 32a of the connection pipe 32. At this time, the external thread portions 30a and 31a are not in contact with each other. At this time, the female screw portion 3 of the connection pipe 32
2a is formed in a reverse threaded structure including a right-handed screw structure and a left-handed screw structure in the longitudinal direction, and each of the male screw portions 30a and 31a of the fuel gas supply pipe 30 and the separator-side fuel gas supply pipe 31 is also provided with a reverse screw structure. By rotating 32 in the same direction, both gas supply pipes 30, 31 can be tightened and fixed. The oxidizing gas supply manifold 15 is also arranged and configured in the same manner as the fuel gas supply manifold 14. In this oxidizing gas supply manifold 15 as well, an oxidizing gas supply pipe 34 is provided for each separator 3 via a throttle section 36. Connected. The plurality of oxidizing gas supply pipes 34 are also alternately branched from the oxidizing gas supply manifold 15 to both sides at different levels. The male thread portions 35a and 34a of the separator-side oxidant gas supply pipe 35 and the oxidant gas supply pipe 34 connected to the respective oxidant gas supply holes 27B are screwed and connected by the female thread portions 32a of the connection pipe 32. ing. The fuel gas supply pipe 30 and the separator-side fuel gas supply pipe 31, and the oxidant gas supply pipe 34 and the separator-side oxidant gas supply pipe 35 constitute a reaction gas supply pipe.

Here, each throttle 33 at the connection between the fuel gas supply manifold 14 and each fuel gas supply pipe 30, the oxidant gas supply manifold 15, and each oxidant gas supply pipe 3
The ratio of the hole diameter of each of the constricted portions 36 of the connection portion with No. 4 is determined by the supply amount and supply pressure of each reaction gas and the gas supply pipes 30 to be laminated.
4 are set in relation to the number of stages. In the embodiment, when the supply pressure of the reaction gas is, for example, 1 atm, the diameter of each of the apertures 33, 36 is φ0.4 mm, φ
By setting it to about 0.7 mm, the fuel gas supply hole 2 of each separator 3 in which the single cell 2 having a diameter of about 150 mm is installed.
7A and the oxidizing gas supply holes 27B can be supplied with the respective reaction gases in an amount suitable for power generation at a ratio of about 1: 5,
The power generation output can be stabilized. In the embodiment shown in FIG.
The separators 3 of the stack 4 in the solid oxide fuel cell 1 are stacked, for example, in 50 stages via the single cells 2, and the separators 3 at both ends thereof are provided on the front surface 22A side or the rear surface 22B side facing inward, respectively. Each of the other fuel gas supply pipes 3
0 and the oxidizing gas supply pipe 34 are sealed with a cap nut.

The solid oxide fuel cell 1 according to the present embodiment has the above-described structure. When assembling the fuel cell, a plurality (for example, about 50 cells) of the single cells 2 and the separators 3 are formed.
Are alternately coaxially stacked, and the
The fuel gas supply holes 27A and the oxidant gas supply holes 27B formed opposite to each other are alternately rotated in the circumferential direction by 90 ° to be arranged in a staggered manner in the stacking direction to form the stack 4. Fixing plates 6 and 7 are provided at both ends of the stack 4 in the axial direction.
And the stack 4 is tightened and fixed with a plurality of stud bolts 8. Next, each fuel gas supply pipe 30 of the fuel gas supply manifold 14 and a separator side fuel gas supply pipe 31 connected to the fuel gas supply hole 27A of each separator 3 are screwed together via a ceramic connection pipe 32. Connect. At this time, the separator-side fuel gas supply pipe 31
Are staggered in the laminating direction to form a gap, so that even if the thickness and diameter of the separator 3 and the gas supply pipes 30 and 31 are small, the connection operation by the connection pipe 32 can be easily performed manually. The connection between the oxidizing gas supply pipe 34 of the oxidizing gas supply manifold 15 and the separator-side oxidizing gas supply pipe 35 is similarly performed using the connection pipe 32.

The fuel gas supply manifold 14 and the oxidant gas supply manifold 15 are fitted into the slits 6b, 7b of the fixed plates 6, 7 at both ends, and are fixed to the fixed plates 6, 7 with nuts 16, respectively. At this time, if the tightening force of the nuts 6, 7 is set to be substantially the same as the tightening force of the stud bolts 8, the load of the thermal expansion of the stack 4 due to the subsequent temperature rise can be set to the same level. The solid oxide fuel cell 1 thus obtained is connected to the gas supply pipes 30, 31 and 3.
The staggered arrangement of the 4 and 35 makes it difficult for them to come into contact with each other, thereby improving the assemblability. Further, the gas supply pipes 30, 31, 34, 3 temporarily laminated at the same position in the left-right direction
Even if the gas supply pipes 5 swing and come into contact with each other, the ceramic connection pipes 32...
It is possible to prevent an electrical short circuit due to contact between the first, the third, and the third 35. In particular, by making the outer diameter of the connection pipe 32 a quadrangular prism shape and making the outer diameter larger than that of the gas supply pipes 30, 31, 34, and 35, the contact between the gas supply pipes 30, 31, 34, and 35 can be reliably prevented. In addition, when the ceramic connection pipe 32 is attached to the gas supply pipes 30, 31, 34, and 35, the connection pipe 32 can be easily attached manually, thereby improving workability.

Next, the operation of the solid oxide fuel cell 1 according to the embodiment will be described. First, the fuel gas from the fuel gas supply manifold 14 is distributed to the fuel gas supply pipe 30, the connection pipe 32, and the separator-side fuel gas supply pipe 31 through each of the throttles 33, and further, through each fuel gas supply hole 27A. 3 is supplied to the concave portion 26A on the side of the surface 22A and supplied to a plurality of spiral grooves 28A. On the other hand, an oxidizing gas from the oxidizing gas supply manifold 15 is supplied to the oxidizing gas
Are distributed to the connection pipe 32 and the separator-side oxidizing gas supply pipe 35, and are further introduced into the recesses 26B on the back surface 22B side in the respective separators 3 through the respective oxidizing gas supply holes 27B to form a plurality of spiral grooves 28B. Supplied to Here, the oxygen contained in the oxidant gas moves in the form of oxygen ions inside the solid electrolyte plate 18 of the single cell 2 from the positive electrode 19 side to the negative electrode 20 side, and is contained in the fuel gas on the negative electrode 20 side. Reacts chemically with hydrogen gas. The heat generated by the chemical reaction heats the solid oxide fuel cell 1 from the inside and generates a potential difference between the positive electrode 19 and the negative electrode 20.

On the surface 22A side of the separator 3,
Unreacted fuel gas and water vapor generated by a chemical reaction are discharged from the fuel gas discharge nozzle 29A, and unreacted oxidant gas is discharged from the oxidant gas discharge nozzle 29B on the back surface 22B side of the separator 3. Both discharge nozzles 29A, 2
The fuel gas and the oxidant gas discharged from 9B are mixed, for example, outside the separator 3, and the solid oxide fuel cell 1 is heated from the outside by heat generated by a chemical reaction (combustion). When the vicinity of the connection pipe 32 is heated, the male screw portions 30a, 31a of the gas supply pipes 30, 31 (34, 35) made of metal having a higher thermal expansion coefficient than the ceramic connection pipe 32, such as stainless steel, are thermally expanded. As a result, the contact with the female screw portion 32a of the connection pipe 32 can be reliably prevented from leaking the reaction gas.

As described above, according to the solid oxide fuel cell 1 of the present embodiment, the fuel gas supply holes 27A and the oxidizing gas supply holes 27B of the separator 3 are stacked in a staggered manner in the stacking direction, so that the fuel Gas supply manifold 14
And oxidant gas supply manifold 15 and fuel gas supply hole 2
7A and the oxidizing gas supply holes 27B are connected to the gas supply pipes 30, 3
The connection work via the connection pipes 1, 34, 35 and the connection pipe 32 is easy, the contact between the reaction gas supply pipes can be prevented, and the workability is improved. Even if these gas supply pipes 30, 31, or 34, 35 fluctuate during the operation of the solid oxide fuel cell 1, they can be prevented by the contact between the insulating (non-conductive) connection pipes 32, and electrical Short circuits can be reliably prevented.
Also, during power generation, due to the difference in the coefficient of thermal expansion between the insulating connecting pipe 32 and the metal gas supply pipes 30, 31, 34, 35, the connecting portions of the connecting pipe 32 and the metal gas supplying pipes 30, 31, ensure reliable leakage of the reaction gas. , And a decrease in power generation efficiency can be prevented.

In the above-described embodiment, the fuel and oxidizing gas supply holes 27 of each separator 3 in the stacking direction are provided.
A, 27B and the gas supply pipes 30, 31, 34, 35 are arranged in a staggered arrangement, and the gas supply pipes 30, 31, 34, 3
5 is connected via the insulating connection pipe 32, but the present invention is not limited to the above embodiment. For example, the fuel and oxidizing gas supply holes 2 of the separators 3 in the stacking direction.
7A, 27B and the gas supply pipes 30, 31, 34, 35 are arranged in a staggered arrangement, and the insulating connection pipe 3 is used.
2, the gas supply pipe 30, 31 or 34,
35 may be connected to each other (insulated).
Alternatively, conversely, the fuel and oxidizing gas supply holes 27A, 27B of each separator 3 and the gas supply pipes 30, 31, 3,
The reaction gas supply holes 27A and 27B are arranged in a line and stacked without adopting the staggered arrangement of the fuel and oxidant gas supply manifolds 14 and 15 and the fuel and oxidant gas supply holes 27A and 27B. Gas supply pipes 30 and 3 connecting
Only the structure in which the insulating connection pipe 32 is connected between 1, 34, and 35 may be adopted. In either case, the gas supply pipes 30, 31 or 3 adjacent in the stacking direction
Electrical short circuit due to contact between 4, 35 can be prevented.
In the former case, the staggered arrangement can improve the assemblability of the solid oxide fuel cell 1. In the latter case, the outer diameters of the connection pipes 32 are brought into contact with each other in the laminating direction of the separators 3 so that the stability is good, and the gas supply pipes 30, 31, or 3
Electrical short circuit due to contact between the 4, 35 can be reliably prevented.

When the fuel gas supply holes 27A and the oxidant gas supply holes 27B of the stacked separators 3 are arranged in a staggered manner, the fuel gas supply holes 27A or the oxidant gas supply holes 2A
The circumferential shift angle of 7B is not limited to 90 ° and can be set to any angle. Further, the shift angle does not necessarily need to be constant, and may be different from each other. Also, fuel gas supply holes 27 formed in each separator 3
A and the oxidizing gas supply holes 27B are not necessarily one each, and two or more may be provided. In this case, a plurality of fuel gas supply manifolds 14 and oxidant gas supply manifolds 15 may be provided, or a single manifold may be supplied with a plurality of branch pipes. The female thread portion 32a of the insulating connection tube 32 is not limited to the reverse thread, and may be formed by, for example, a one-way female thread. In this case, two gas supply pipes 30 to be connected,
It is also possible to form male threads in the same direction also at the ends of 31 or 34, 35, and connect the connecting pipes 32 to both ends sequentially by screwing.

[0025]

As described above, in the solid oxide fuel cell according to the present invention, since the reactant gas supply pipes arranged in the stacking direction are arranged so as to be shifted from each other in the direction intersecting the stacking direction, the solid electrolyte fuel cells are stacked. A gap is formed between the reaction gas supply pipes in the directions, so that connection of the reaction gas supply pipe between the separator and the reaction gas supply manifold can be easily performed, and assemblability by manual work or the like is improved.

Further, in the solid oxide fuel cell according to the present invention, at least a part of the reaction gas supply pipe is provided with an insulative tube to ensure electrical insulation, so that the reaction gas supply pipe is arranged in the stacking direction. Even if it oscillates, the contact between the insulating tubes keeps the electrical insulation between the reaction gas supply pipes and also prevents the electrical short circuit.

In the solid oxide fuel cell according to the present invention, the reaction gas supply pipes arranged in the stacking direction are arranged so as to be shifted from each other in a direction intersecting the stacking direction, and at least one of the reaction gas supply pipes is arranged. Since an insulating tube is provided in the section to ensure electrical insulation, a gap is created between the reaction gas supply pipes, and the connection of the reaction gas supply pipe between the separator and the reaction gas supply manifold is performed. It is easy to perform and the assemblability is improved. In addition, even if the reaction gas supply pipe oscillates in the stacking direction, the electrical insulation between the reaction gas supply pipes is maintained due to the contact between the insulative pipes, and an electrical short circuit can be prevented.

Further, a female screw portion is formed in the insulating tube portion,
The reaction gas supply pipes on the separator side and the reaction gas supply manifold side are screwed into the female screw part, and the thermal expansion coefficient of the reaction gas supply pipe is larger than that of the insulating pipe part. Adhesion with the reaction gas supply pipe is improved, so that gas leakage at the connection portion is eliminated and a decrease in power generation efficiency can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view of a solid oxide fuel cell according to an embodiment of the present invention.

FIG. 2 is a plan view of the solid oxide fuel cell shown in FIG.

FIG. 3 is a diagram showing the structure of an extraction electrode portion in FIG.
It is a line part longitudinal cross-sectional view.

FIG. 4 is a partial longitudinal sectional view showing a laminated structure of a separator and a single cell.

FIG. 5 is a plan view of the front side of the separator.

FIG. 6 is a configuration diagram showing a fuel gas supply manifold and a fuel gas supply pipe.

7 is a partially enlarged view showing a connection portion between the fuel gas supply manifold and the fuel gas supply pipe shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Solid electrolyte fuel cell 2 Single cell (power generation cell) 3 Separator 14 Fuel gas supply manifold 15 Oxidant gas supply manifold 30 Fuel gas supply pipe (reaction gas supply pipe) 30a, 31a Male screw part 31 Separator side fuel gas supply pipe ( Reaction gas supply pipe) 32 Connection pipe (tube part) 32a Female thread part 34 Oxidant gas supply pipe (reaction gas supply pipe) 35 Separator side oxidant gas supply pipe (reaction gas supply pipe)

Claims (4)

[Claims] 1. A solid oxide fuel cell in which power generation cells and separators are alternately stacked, and each of the separators and a reaction gas supply manifold are connected by a reaction gas supply pipe. Wherein the reactant gas supply pipes are arranged so as to be shifted from each other in a direction intersecting the stacking direction. 2. A solid oxide fuel cell comprising power generation cells and separators alternately stacked, and each of said separators and a reaction gas supply manifold connected by a reaction gas supply pipe. A solid oxide fuel cell characterized in that at least a part of the solid electrolyte fuel cell is provided with an insulative tube to ensure electrical insulation. 3. A solid oxide fuel cell in which power generation cells and separators are alternately stacked, and each of the separators and a reaction gas supply manifold are connected by a reaction gas supply pipe, and are arranged in the stacking direction. The reaction gas supply pipes are arranged so as to be shifted from each other in a direction intersecting with the laminating direction, and at least a part of the reaction gas supply pipe is provided with an insulative tube to ensure electrical insulation. A solid oxide fuel cell comprising: 4. A female screw portion is formed in said insulating tube portion,
4. The solid oxide fuel cell according to claim 2, wherein reaction gas supply pipes on the separator side and the reaction gas supply manifold side are screwed into the female screw portion.