JPH0551153B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in solid electrolyte fuel cells and methods for manufacturing the same.

[Prior Art] Conventionally, as a solid electrolyte fuel cell, one using an internal air and external fuel supply system as shown in FIG. 4, for example, is known.

1 in the figure is a porous ceramic tube as a base tube. On this tube 1, an oxygen electrode 2 is fixed. An interconnector 3 is fixed onto the oxygen electrode 2. A holding material 4 is fixed onto this interconnector 3. An electrolyte material 5 is fixed on a portion of the interconnector 3 and the oxygen electrode 2. A fuel electrode 6 is fixed onto this electrolyte material 5.

A fuel cell having such a structure has conventionally been manufactured using a thermal spraying apparatus shown in FIG. 11 in the figure is
This is a thermal spray booth that is a component of the rotary traverse device 12. The rotary traverse device 12 includes:
It mainly consists of a torch driving section 13 and a base tube rotating section 14 above the torch driving section 13. A thermal spray gun 16 is provided above the torch driving section 13 for spraying the base tube 15 attached to the base tube rotation section 14 . Near the thermal spraying booth 11, there are a powder supply device 17, a control device 18, and a power source 1.
9 is provided. That is, conventionally, the base tube 15
The fuel cell shown in FIG. 4 was manufactured while controlling the torch driving section 13 and the base tube rotating section 14 of the rotary traverse device 12 according to the design shape of the fuel cell.

[Problems to be Solved by the Invention] However, according to the prior art, when the interconnector 4 is fixed, only one side of the interconnector 4 is subjected to a thermal load due to its structure, so stress ( Thermal stress, bending stress) is generated, and inherent defects (cracks) in the tube 1, the oxygen electrode 2, and the electrolyte material 5 occur. However, although this drawback does not become a major problem in the initial stage, the crack progresses due to long-term operation or repeated operation and stoppage, resulting in damage to the fuel cell and a decrease in performance.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid electrolyte fuel cell that can suppress the occurrence of cracks in the base tube, oxygen electrode, and electrolyte material, and a method for manufacturing the same.

[Means for solving the problem] The first invention of the present application includes a base tube, an oxygen electrode fixed on the entire circumference of the base tube, and a plurality of oxygen electrodes fixed at symmetrical positions in the circumferential direction of the oxygen electrode. a part of the interconnector and an electrolyte material fixed to the oxygen electrode, a fuel electrode fixed to the electrolyte material, and a portion of the interconnector not covered with the electrolyte material. The main feature is that the fuel electrode is disposed in the fuel electrode and includes a holding material made of the same material as the fuel electrode.

The second invention of the present application includes a step of fixing an oxygen electrode on the entire circumference of the base tube, and arranging thermal spray guns at symmetrical positions on the circumference of the base tube, and using these spray guns to attach the interconnector to the base tube. a step of fixing an oxygen electrode at symmetrical positions in the circumferential direction, a step of fixing an electrolyte material to a part of the interconnector and the oxygen electrode, a step of fixing a fuel electrode on the electrolyte material, The method further comprises the step of fixing a holding material made of the same material as the fuel electrode to a portion of the interconnector that is not covered with the electrolyte material.

[Function] According to the present invention, the stress applied to the base tube (porous ceramic tube), the oxygen electrode, and the electrolyte material can be reduced compared to conventional ones, and the occurrence of cracks can be suppressed.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is an explanatory diagram of a solid electrolyte fuel cell according to the present invention. 21 in the figure is a porous ceramic tube serving as a base tube. This tube 21
A ceramic oxygen electrode 22 is fixed on the top. Interconnectors 23a and 23b made of Ni, Al, etc. are fixed to circumferentially symmetrical positions (180 degree positions) of this oxygen electrode 22. An electrolyte material 24 made of zirconia or the like is fixed to a portion of each of these interconnectors 23a, 23b and the oxygen electrode 22. This electrolyte material 2
A fuel electrode 25 made of Ni or the like is fixed on top of the fuel electrode 4 . Holding members 26a and 26b made of the same material as the fuel electrode 25 are fixed onto the interconnectors 23a and 23b, respectively.

The solid electrolyte fuel cell according to the above embodiment has a first
As shown in the figure, interconnectors 23a and 2 are placed at symmetrical positions (180 degree positions) in the circumferential direction of the oxygen electrode 22, respectively.
3b, when the interconnectors 23a, 23b are fixed, the interconnectors 23a, 23b are fixed at the same time. Therefore, the porous ceramic tube 21 and the oxygen electrode 2
2. The stress applied to the electrolyte material 24 can be reduced and the occurrence of cracks can be suppressed. In particular, when the interconnectors 23a and 23b are arranged in the direction of dividing the circumference into two as shown in FIG. 1, the thermal stress can be drastically reduced to almost zero by arranging the thermal spraying equipment facing each other.

The fuel cell having the above structure is manufactured using a thermal spraying apparatus shown in FIG. Reference numeral 31 in the figure is a thermal spray booth that includes a rotary traverse device 32 as one component.
The rotary traverse device 32 mainly includes a torch driving section 33 and a base tube rotating section 34 above the torch driving section 33. Above the torch driving section 33, thermal spray guns 36a and 36b are provided, respectively, for spraying the base tube 35 attached to the base rotating section 34. A powder supply device 37, a control device 38, and a power source 39 are provided near the thermal spraying booth 31.

When manufacturing a fuel cell using a thermal spraying apparatus manufactured in this manner, the torch driving section 33 and the substrate tube rotation section 34 of the rotary traverse device 32 are controlled in accordance with the design shape of the substrate tube 35, and the rotation of the substrate tube 35 is controlled. Thermal spraying is performed by arranging thermal spraying guns 36a and 36b at opposing positions on the circumference. That is, first, after fixing the oxygen electrode 22 on the base tube 35, the thermal spray guns 36a, 3
6b fix the interconnectors 23a and 23b at symmetrical positions in the circumferential direction of the oxygen electrode 22, respectively. Subsequently, the electrolyte material 24 is fixed to a portion of the interconnectors 23a, 23b and the oxygen electrode 22. Next, holding members 26a and 26b, which are the same members as the fuel electrode 25, are fixed onto the electrolyte material 24 to manufacture a solid electrolyte fuel cell. Therefore, if the interconnectors 23a and 23b are fixed by the method of the present invention, the interconnectors 23a and 23b will be fixed at the same time, and the porous ceramic tube 2 will be fixed as described above.
1, the oxygen electrode 22, and the electrolyte material 24 can be drastically reduced to almost zero, and the occurrence of cracks can be suppressed.

In addition, Ni-
The Al-based interconnector was thermally sprayed under the following conditions in order to be fixed to only one side as shown in Fig. 6a and b (conventional example).

Plasma spraying conditions Primary gas (Ar): 50/min Secondary gas (H ₂ ): 8/min Current: 650A Voltage: 65V Powder feed gas: 3/min Powder feed rate: 20g/min Spraying distance: 120mm Gun Traveling speed: 10 m/min As a result, the base tube could not withstand the thermal stress and broke 1 minute after the start of thermal spraying.

Next, thermal spraying was carried out under the same conditions to fix the interconnectors in symmetrical positions as shown in Fig. 7 (invention). After about 10 minutes of thermal spraying, there was no damage to the base tube, and the interconnectors with the predetermined film thickness were It is now possible to secure the connector. From the above, it was confirmed that the present invention is superior to the conventional method.

In the above embodiment, a case has been described in which the interconnectors are provided at positions opposite to each other on the circumference of the oxygen electrode (positions at 180 degrees); however, the present invention is not limited to this. For example, there is a case where a pair of interconnectors are further arranged at positions whose phases are shifted by 90 degrees (positions divided into four equal positions in the circumferential direction). Also, for example, if another pair of interconnectors are placed at positions with a phase shift of 90 degrees (at positions divided into four equal parts in the circumferential direction), or 6,
It is also possible to arrange the interconnectors in the directions divided into 8, 10, . . . .

In the present invention, when batteries having a plurality of interconnectors are grouped together, the method for electrically connecting adjacent batteries is, for example, as follows. That is, first, the interconnectors of adjacent batteries are connected to each other, and the positive electrode sides of the square batteries are commonly connected. Furthermore, on the negative electrode side, the exposed portions of the fuel electrode on the surface are connected to each other in common.

At the end of the battery array, a conductor that commonly connects the interconnectors of each battery and a conductor that commonly connects the fuel electrodes of each battery are arranged electrically insulated from each other. Use as a negative potential current collector.

Further, the thermal spraying apparatus according to the present invention is not limited to the one shown in FIG. 2, but may be the one shown in FIG. 3. This thermal spraying device has two thermal spraying robots 4 compared to the one in Figure 2.
1a and 41b are newly added to the rotary traverse device 32, and thermal spray guns 42a and 42b are provided at the tips of these robots 41a and 41b, respectively.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a highly reliable solid electrolyte fuel cell that can suppress the occurrence of cracks in the base tube, oxygen electrode, and electrolyte material, and a method for manufacturing the same.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a solid electrolyte fuel cell according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a thermal spraying apparatus according to the present invention, and FIG. 3 is an explanatory diagram of another thermal spraying apparatus according to the present invention, Fig. 4 is an explanatory diagram of a conventional solid electrolyte fuel cell, Fig. 5 is an explanatory diagram of a conventional thermal spraying device, and Fig. 6 is a conventional diagram in which an interconnector is fixed only on one side in the longitudinal direction of a base tube to which an oxygen electrode is fixed. FIG. 7 is an explanatory diagram of an example, in which figure a is a front view, figure b is a schematic side view, and figure 7 shows an interconnector fixed symmetrically in the longitudinal direction of a base tube to which an oxygen electrode is fixed. FIG. 2 is an explanatory diagram of the present invention. 21... Porous ceramic tube, 22...
Oxygen electrode, 23a, 23b...interconnector, 2
4... Electrolyte material, 25... Fuel electrode, 26a, 26
b...Holding material, 31...Thermal spray booth, 32...Rotary traverse device, 33...Torch drive unit, 34
...Base tube drive section, 36a, 36b, 42a, 4
2b...Thermal spray gun, 41a, 41b...Thermal spray robot.

Claims (1)

[Scope of Claims] 1. A base tube, an oxygen electrode fixed on the entire circumference of the base tube, an interconnector fixed at symmetrical positions in the circumferential direction of the oxygen electrode, and the interconnector. an electrolyte material partially fixed to the oxygen electrode, and a fuel electrode fixed on the electrolyte material;
A solid electrolyte fuel cell characterized by comprising a holding material disposed on a portion of the interconnector that is not covered with an electrolyte material and made of the same material as the fuel electrode. 2. A step of fixing an oxygen electrode on the entire circumference of the base tube,
arranging thermal spray guns at symmetrical positions on the circumference of the base tube, and fixing the interconnectors at symmetrical positions in the circumferential direction of the oxygen electrode using these spray guns; a step of fixing an electrolyte material to the electrode and the oxygen electrode, a step of fixing a fuel electrode on the electrolyte material, and a step of fixing a holding material made of the same material as the fuel electrode to a portion of the interconnector that is not covered with the electrolyte material. A method for manufacturing a solid electrolyte fuel cell, comprising the step of fixing.