JP2001093552A - Tube connection structure for a fuel battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube connection structure for a fuel battery that prevents leakage of gas in the region of connecting the tubes without distortion. SOLUTION: A fuel gas inlet tube 27 is inserted in a ceramic fuel gas guide tube 23, and heat-expanded to connect with the gas guide tube 23. The internal peripheral surface of the inserted end of the fuel gas inlet tube 27 is formed to have a tape-like thin end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel cell piping connection structure.

[0002]

2. Description of the Related Art In a fuel cell, a power generation membrane in which an electrolyte is sandwiched between an oxidizer electrode and a fuel electrode is maintained at a high temperature (100%).
0 ° C.), an oxidant gas such as air is supplied to the oxidant electrode side, and a fuel gas such as hydrogen is supplied to the fuel electrode side, whereby these gases are electrochemically reacted with an electrolyte. Power can be obtained.

In such a power generation device using a fuel cell, a stack is formed by connecting a large number of the power generation films in series via an interconnector, and a manifold of the gas is attached to the stack, and the gas is discharged. The required electromotive force can be obtained by being able to collectively supply the power generation films of the stack.

Since the temperature difference between the inside and the outside of the furnace is large, if the piping in the furnace connected to the manifold and the piping outside the furnace for supplying the gas are constituted by a single member, The pipe may be distorted near the boundary between the inside and the outside of the furnace, and the fixed support portion of the pipe near the boundary may be cracked or otherwise inoperable.

For this reason, as shown in FIG. 6, a pipe 111 outside the furnace for supplying the gas is made of a metal material,
A pipe 112 in the furnace connected to the manifold is made of a ceramic material, and a metal pipe 111 is inserted into the ceramic pipe 112 (see FIG. 6A). The pipe 111 is thermally expanded to expand its diameter, and the outer peripheral surface of the pipe 111 is connected to the pipe 1.
By deforming plastically so as to be in close contact with the inner peripheral surface of the pipe 12 (see FIG. 6B), it is possible to prevent the generation of distortion in the fixed support portion while securely connecting the pipes 111 and 112. .

[0006]

In the pipe connection structure as described above, the metal pipe 111 must have a sufficient thickness so that the pipe 112 does not crack when the pipe 111 is compressed by thermal expansion. The size is set. However, since the strength of the ceramic pipe 112 varies from production lot to production lot, in some cases, the
12 may be cracked, resulting in gas leakage or the like.

In view of the above, an object of the present invention is to provide a fuel cell piping connection structure capable of preventing gas leakage from a connection portion while preventing generation of distortion.

[0008]

In order to solve the above-mentioned problems, a first fuel cell piping connection structure according to the present invention comprises a metal pipe inserted into a ceramic pipe. In a fuel cell pipe connection structure for connecting these pipes by thermally expanding the pipes,
It is characterized in that the inner peripheral surface on the insertion end side of the metal pipe is formed in a tapered shape so as to become thinner toward the end side.

According to a second aspect of the present invention, there is provided a fuel cell piping connection structure according to the present invention, wherein a metal piping is inserted into a ceramic piping to thermally expand the metal piping. Thus, in the pipe connection structure for a fuel cell connecting these pipes, the outer peripheral surface on the insertion end side of the metal pipe is formed in a tapered shape so as to become thinner toward the end side, while the metal pipe is formed. The inner peripheral surface at the end of the ceramic pipe into which is inserted is formed into a tapered shape so as to be thinner toward the end, and the metal pipe is urged toward the ceramic pipe. The present invention is characterized in that an urging means is provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the fuel cell piping connection structure according to the present invention will be described below, but the present invention is not limited to the following embodiments.

[Embodiment of the First Invention] An embodiment of a fuel cell piping connection structure according to the first invention will be described with reference to FIGS. 1 is a schematic structural view of a power generator of a flat solid electrolyte fuel cell to which the piping connection structure is applied, FIG. 2 is a cross-sectional view taken along line II-II of FIG.
FIG. 3 is an enlarged view illustrating the operation of the arrow III in FIG.

As shown in FIG. 1, the interior of the furnace 11 is divided into three parts by an upper partition plate 12 and a lower partition plate 13, and a space above the upper partition plate 12 forms a battery chamber 14, and an upper partition plate 12 between the lower partition plate 13 and the refractory material 1
An exhaust gas chamber 15 is formed through the intermediary 7. Upper partition plate 1
A stack 18 in which a plurality of flat solid electrolyte fuel cells are stacked is placed on the upper bottom plate 16.

As shown in FIGS.
The manifolds 19 to 22 for the inlet and outlet of the fuel gas and the oxidizing gas (air) are attached to both side surfaces of the fuel cell and the oxidizing gas (air) so as to correspond to each other. The fuel gas inlet manifold 19 is connected to an upper end of a fuel gas inlet pipe 23 which is a ceramic pipe passing through the bottom plate 16 and the upper partition plate 12 so that the lower end is located in the exhaust gas chamber 15. The fuel gas outlet manifold 20 is connected to a fuel gas discharge pipe 24, which is a ceramic pipe that penetrates the bottom plate 16 and the upper partition plate 12 so that the lower end is positioned in the exhaust gas chamber 15. The oxidizing gas inlet manifold 21 is connected to an oxidizing gas introducing pipe 25 which is a ceramic pipe that penetrates through the bottom plate 16 and the upper partition plate 12 such that the lower end is located in the exhaust gas chamber 15. The oxidizing gas outlet manifold 22 is connected to an oxidizing gas discharge pipe 26 which is a ceramic pipe that penetrates through the bottom plate 16 and the upper partition plate 12 such that the lower end is located in the exhaust gas chamber 15.

At the lower end of the fuel gas introduction pipe 23, FIG.
As shown in (a), the base end side of a fuel gas inlet pipe 27 which is a metal pipe whose inner peripheral surface is tapered so as to be thinner toward the base end side is inserted. At the lower end of the fuel gas discharge pipe 24, similarly to the fuel gas inlet pipe 27, a fuel gas outlet pipe which is a metal pipe whose inner peripheral surface is tapered so as to be thinner toward the base end side. 2
8 is inserted at the base end side. At the lower end of the oxidizing gas introduction pipe 25, like the fuel gas inlet pipe 27, an oxidizing gas made of a metal pipe whose inner peripheral surface is tapered so as to be thinner toward the base end side. The base end side of the inlet pipe 29 is inserted. At the lower end of the oxidizing gas discharge pipe 26, similarly to the fuel gas inlet pipe 27, an oxidizing gas which is a metal pipe whose inner peripheral surface is tapered so as to be thinner toward the base end side. The base end side of the outlet pipe 30 is inserted.

That is, the metal pipes 27 to 30 are formed such that the inner peripheral surface thereof is tapered so that only the ends inserted into the ceramic pipes 23 to 26 are thin.

As shown in FIGS. 1 and 2, the fuel gas inlet pipe 27 penetrates through the lower partition plate 13 and the furnace 11 and has a tip located outside the furnace 11. Fuel gas outlet pipe 2
8 passes through the lower partition plate 13 and the furnace 11 and
1 has a tip located outside. Oxidant gas inlet pipe 29
Passes through the lower partition plate 13 and the furnace 11
The tip is located outside of. Oxidant gas outlet pipe 30
Passes through the lower partition plate 13 and the furnace 11
The tip is located outside of. These tubes 27-30
While penetrating the lower partition plate 13 without a gap,
It passes through the furnace 11. Flexible joints 31 to 34 are attached to the tips of these tubes 27 to 30, respectively, so that the gap between the tubes 27 to 30 and the furnace 11 is shielded.

In such a flat solid electrolyte fuel cell power generator, when the operating temperature (about 1000 ° C.) is set, the metal pipes 27 to 30 expand relatively thermally, while the ceramic pipes 27 to 30 expand. Since the tubes 23 to 26 hardly thermally expand, the outer peripheral surfaces of the metal tubes 27 to 30 on the tip side are in close contact with the inner peripheral surfaces of the ceramic tubes 23 to 26 and are plastically deformed. The tubes 27-30
And the tubes 23 to 26 made of ceramics are securely connected (see FIG. 3B).

Subsequently, when the fuel gas 1 is supplied from the fuel gas inlet pipe 27 and the oxidant gas 2 is supplied from the oxidant gas inlet pipe 29, the fuel gas 1 is supplied to the fuel gas inlet pipe 27 and the fuel gas introduction pipe 23. Is supplied into the fuel gas inlet manifold 19 without leaking from the joint portion of the stack 1.
At the same time, the oxidizing gas 2 is supplied into the oxidizing gas inlet manifold 21 without leaking from the connecting portion between the oxidizing gas inlet pipe 29 and the oxidizing gas introducing pipe 25 and is sent into the stack 18. , These gases 1, 2
Reacts electrochemically in the stack 18 to generate power.

The fuel gas 1 used for power generation in the stack 18
Is connected to the fuel gas outlet manifold 20 from within the stack 18.
The fuel gas is discharged into the fuel gas discharge pipe 24 through the fuel gas discharge pipe 24 and is discharged to the outside without leaking from the joint portion between the fuel gas discharge pipe 24 and the fuel gas outlet pipe 28, while the oxidizing gas supplied to the stack 18 for power generation 2 is an oxidizing gas discharge pipe 26 through the oxidizing gas outlet manifold 22 from inside the stack 18.
The gas is discharged to the outside without leaking from the connecting portion between the oxidizing gas discharge pipe 26 and the oxidizing gas outlet pipe 30.

That is, the ceramic tubes 23-2
The metal pipes 27 to 30 are formed by tapering the inner peripheral surfaces of the pipes 27 to 30 so that only the distal ends of the metal pipes 27 to 30 inserted into the pipes 6 are thinned.
Therefore, plastic deformation is more likely to occur at the tip side.

For this reason, the ceramic pipes 23-
There is variation in the strength of 26, and the metal pipe 27-
Even if cracks occur in the tubes 23 to 26 at the time of pressure bonding due to thermal expansion of 30, the distal ends of the tubes 27 to 30 are easily plastically deformed. Therefore, as shown in FIG. The distal end side of the pipes 27 to 30 is the above-mentioned ceramic pipe 2
The state in which the pipes 3 to 26 are in close contact with the inner peripheral surfaces of the pipes 23 to 26 is maintained without being damaged.

Therefore, according to such a fuel cell pipe connection structure, even if the strength of the ceramic pipes 23 to 26 varies, the metal pipes 27 to 30 can be used.
Cracks due to the thermal expansion of the pipes are restricted to only the lower end portions of the pipes 23 to 26, and the distal ends of the pipes 27 to 30 are
6 can always be kept in close contact with the inner peripheral surface, so that it is possible to prevent gas from leaking from the connection portion while preventing the occurrence of distortion.

[Embodiment of the Second Invention] An embodiment of the pipe connection structure for a fuel cell according to the second invention will be described with reference to FIG. FIG. 4 is an extracted enlarged sectional view of a main part of the pipe connection structure. However, the same members as those of the above-described embodiment will be denoted by the same reference numerals as those used in the description of the above-described embodiment, and the description thereof will be omitted.

As shown in FIG. 4, the fuel gas introduction pipe 23 '
Is formed in a tapered shape such that the inner peripheral surface at the lower end has a larger inner diameter toward the lower end. On the other hand, the fuel gas inlet pipe 27 ′ is slidably supported by the lower partition plate 13, and is formed in a tapered shape such that the outer peripheral surface of the distal end has a smaller outer diameter toward the distal end side. A flange portion 2 is provided in the exhaust gas chamber 15 above the partition plate 13.
7'a is provided. A compression coil spring 35 made of ceramics is provided between the lower partition plate 13 and the flange portion 27'a of the fuel gas inlet pipe 27 '.

That is, the fuel gas inlet pipe 27 ′ is pressed by the urging force of the compression coil spring 35 so that the tapered end of the fuel gas inlet pipe 27 ′ is always in close contact with the tapered lower end of the fuel gas introduction pipe 23 ′. It is. In the present embodiment, such a flange portion 27′a, the compression coil spring 35, and the like constitute an urging unit.

The fuel gas outlet pipe 28 ', the oxidizing gas inlet pipe 29', and the oxidizing gas outlet pipe 30 ', which are other metal pipes, have the same structure as the fuel gas inlet pipe 27'. , A fuel gas discharge pipe 2 which is another ceramic pipe
4 ', oxidizing gas introduction pipe 25', oxidizing gas discharge pipe 2
6 'has the same structure as the fuel gas introduction pipe 23'.

In such a pipe connection structure for a fuel cell, when an excessive adhesion force is applied to the tubes 23 'to 26' due to the thermal expansion of the metal tubes 27 'to 30', the tube 27 'To 30' are moved downward so as to compress and compress the compression coil spring 35 while keeping the tapered tip of the tube 23 'to 26' in close contact with the tapered lower end of the tube 23 'to 26'.

For this reason, the tube 23 'made of ceramics is used.
The metal tube 2 has a variation in the strength of
Excessive adhesion due to thermal expansion of 7'-30 '
3 'to 26', the pipe 2
3 'to 26' without damaging said tubes 27 'to 3'.
0 'can always be brought into close contact with the tubes 23' to 26 '.

Therefore, according to such a pipe connection structure for a fuel cell, similar to the above-described embodiment,
Gas leakage from the connection portion can be prevented while preventing generation of distortion.

Further, even if the temperature in the furnace is lowered and the diameter of the metal pipes 27 'to 30' is reduced, the urging force of the compression coil spring 35 causes the metal pipes 27 'to 30' to be reduced. The pipes 23 'to 2 each having a tapered tip made of ceramics.
Since it is always in close contact with the 6 'tapered lower end, it is possible to prevent gas from leaking between the metal pipes 27' to 30 'and the ceramic pipes 23' to 26 '. it can.

The ceramic tubes 23 'to 2'
6 'is connected to the upper part of each of the manifolds 19 to 22, and the metal pipes 27' to 3 'are provided at the upper ends of the pipes 23' to 26 '.
In the case where the tip of 0 'is connected, the flange portions 27'a to 30'a of the metal tubes 27' to 30 'and the compression coil spring 35 are omitted, and as shown in FIG. Due to the weight of the metal pipes 27 'to 30', the pipe 27 '
It is also possible to press the tip of 〜30 ′ so as to be always in close contact with the upper end of the tube 23 ′ to 30 ′.

In other words, in this embodiment, the urging means is constituted by the flange portions 27'a to 30'a, the compression coil spring 35, and the like. 35, etc., instead of the metal tube 27 '
It is also possible to constitute the biasing means by itself to 30 '.

In such a case, when the temperature in the furnace is lowered and the diameter of the metal pipes 27 'to 30' is reduced,
Due to the weight of the tubes 27 ′ to 30 ′, the metal tube 2
The tapered ends of 7 ′ to 30 ′ are always in close contact with the tapered lower ends of the ceramic tubes 23 ′ to 26 ′, so that the metal tubes 27 ′ to 3 ′.
Leakage of gas from between 0 'and the pipes 23' to 26 'made of ceramics can be easily prevented.

[0034]

According to the first fuel cell piping connection structure of the present invention, a metal piping is inserted inside a ceramic piping, and the metal piping is thermally expanded to connect these pipings. In the pipe connection structure for a fuel cell, the inner peripheral surface of the metal pipe at the insertion end side is formed in a tapered shape so as to be thinner toward the end side, and the insertion end side of the metal pipe is plastically deformed. This facilitates maintaining the state in which the tip end of the metal pipe is in close contact with the inner peripheral surface of the ceramic pipe without damaging the ceramic pipe. Therefore, even if the strength of the ceramic pipe varies, the cracks due to the thermal expansion of the metal pipe are suppressed only at the end of the ceramic pipe, and the insertion end side of the metal pipe is made of ceramic. Since it can be kept in close contact with the inner peripheral surface of the pipe at all times, it is possible to prevent gas leakage from the connection portion while preventing the occurrence of distortion.

The fuel cell pipe connection structure according to the second aspect of the present invention is a fuel cell in which metal pipes are inserted inside ceramic pipes and the metal pipes are thermally expanded to connect these pipes. In the pipe connection structure of the above, the outer peripheral surface at the insertion end side of the metal pipe is formed in a tapered shape so as to be thinner toward the end side, while the ceramic pipe is inserted with the metal pipe. Since the inner peripheral surface on the end side is formed in a tapered shape so as to be thinner toward the end side, and biasing means for biasing the metal pipe toward the ceramic pipe is provided. When excessive adhesion force is applied to the ceramic pipe due to the thermal expansion of the metal pipe, the tapered end of the metal pipe is inserted into the tapered end of the ceramic pipe. While the adhesion can be moved so as to resist the biasing means. Therefore, even if the strength of the ceramic pipe varies, the ceramic pipe may be damaged even if excessive adhesion due to the thermal expansion of the metal pipe may be applied to the ceramic pipe. In addition, since the metal pipe can always be brought into close contact with the ceramic pipe, it is possible to prevent gas leakage from the connection portion while preventing the occurrence of distortion.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a power generator of a flat solid electrolyte fuel cell to which a fuel cell piping connection structure according to a first invention is applied.

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

FIG. 3 is an extracted enlarged view for explaining an operation of an arrow III part in FIG. 1;

FIG. 4 is an extracted enlarged sectional view of a main part of the embodiment of the fuel cell piping connection structure according to the second invention.

FIG. 5 is an extracted enlarged sectional view of a main part of another embodiment of the fuel cell piping connection structure according to the second invention.

FIG. 6 is an extracted enlarged sectional view of a main part of an example of a conventional pipe connection structure of a fuel cell.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel gas 2 oxidant gas 11 furnace 12 upper partition plate 13 lower partition plate 14 battery room 15 exhaust gas chamber 16 bottom plate 17 refractory material 18 stack 19 fuel gas inlet manifold 20 fuel gas outlet manifold 21 oxidant gas inlet manifold 22 oxidant gas Outlet manifold 23,23 'Fuel gas inlet tube 24,24' Fuel gas outlet tube 25,25 'Oxidizer gas inlet tube 26,26' Oxidizer gas outlet tube 23'a ~ 26'a Flange 27,27 'Fuel Gas inlet tube 28, 28 'Fuel gas outlet tube 29, 29' Oxidizing gas inlet tube 30, 30 'Oxidizing gas outlet tube 31-34 Flexible joint 35 Compression coil spring

Continuation of front page (72) Inventor Masahiko Irie 1-1-1 Wadazakicho, Hyogo-ku, Kobe-shi, Hyogo F-term in Mitsubishi Heavy Industries, Ltd. Kobe Shipyard 5H027 AA06

Claims (2)

[Claims] In a fuel cell piping connection structure in which a metal pipe is inserted into a ceramic pipe and the metal pipe is thermally expanded, the metal pipe is inserted. A pipe connection structure for a fuel cell, wherein an inner peripheral surface on an end side is formed in a tapered shape so as to become thinner toward the end side. 2. A fuel cell piping connection structure in which a metal pipe is inserted into a ceramic pipe and the metal pipe is thermally expanded to connect these pipes, wherein the metal pipe is inserted. The outer peripheral surface on the end side is tapered so as to be thinner toward the end side, while the inner peripheral surface on the end side of the ceramic pipe into which the metallic pipe is inserted is closer to the end side. A pipe connection structure for a fuel cell, characterized in that the pipe connection structure is formed in a tapered shape so as to be thin and provided with an urging means for urging the metal pipe toward the ceramic pipe.