JP2002008682A - Solid electrolyte type fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make uniform a distribution of a power output generated inside a single cell by uniformly supplying a reaction gas. SOLUTION: In an inside of an outer perimeter section 14 of a separator 12 of the solid electrolyte type fuel cell, a fuel-gas supply hole 16a and an oxidizer gas supply hole 16b, and a fuel-gas exhaust nozzles 17a..., 17a and an oxidizer gas exhaust nozzle are prepared. Seven dented parts 18a..., 18a are arranged on a surface 15A of the inner perimeter section 15, and seven dented parts are prepared on the back surfaces. Inside of the inner perimeter section 15, a plurality of pipings 19a, 19b, and 19c for fuel gas which connects the fuel-gas supply hole 16a with insides of the dent parts 18a each other, is arrange. A plurality of the oxidizer gas supply holes which connect the oxidizer gas supply hole 16b with the insides of the dent parts on the back surface of the inner perimeter section, is arranged. Spiral dented grooves 21a,..., 21a for fuel gas which whirl around with each dent part 18a as a center, and spiral grooves for oxidizer gas which whirl around with each dent part on the back surface as a center are arranged.

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 having a positive electrode and a negative electrode sandwiched from both sides, and having a positive electrode and a negative electrode, respectively. The present invention relates to a separator for supplying different reaction gases.

[0002]

2. Description of the Related Art Conventionally, there has been known a solid electrolyte fuel cell which does not require a gas seal between a solid electrolyte body and a separator, such as a solid electrolyte fuel cell disclosed in Japanese Patent Application Laid-Open No. 3-129675. I have. FIG. 6 is a perspective view of a main part of a solid oxide fuel cell 1 according to an example of the above-mentioned conventional technology. The solid oxide fuel cell 1 is configured by alternately stacking a single cell 2 having a positive electrode and a negative electrode sandwiching a solid electrolyte plate made of an oxide solid electrolyte such as zirconia from both sides, and a separate plate 3. Have been. On the surface of the separate plate 3 facing the single cell 2, a plurality of annular concave grooves connected to each other are formed coaxially with the central axis P of the solid oxide fuel cell 1. In the vicinity of the central axis P, a fuel gas supply pipe 4 for supplying a fuel gas to the annular groove on one surface side of the separate plate 3 and an oxidizing gas for supplying an oxidizing gas to the annular groove on the other surface side. An agent gas supply pipe 5 is provided so as to penetrate the inside along the central axis P. Then, on the surface of the separate plate 3, the central axis P
The fuel gas and the oxidizing gas circulated from the reaction gas outlets provided in the gas supply pipes 4 and 5 in the vicinity to the outer peripheral side are supplied to the fuel gas outlet 6 opened on the outer peripheral surface of the separate plate 3. And the oxidizing gas is discharged from the oxidizing gas discharge port 7 to the outside.

[0003]

By the way, in the solid oxide fuel cell 1 according to one example of the prior art, a reaction gas outlet for blowing a reaction gas from each of the gas supply pipes 4 and 5 on the surface of the separate plate 3. Is provided only in the vicinity of the central axis P, and is configured to diffuse and supply the fuel gas and the oxidizing gas from the central portion of the separate plate 3 to the outer peripheral portion. For this reason, for example, when the size of the solid electrolyte plate is increased in order to increase the power generation output, a problem arises in that the fuel gas and the oxidizing gas cannot be uniformly and efficiently supplied to the power generation surface of the solid electrolyte plate. That is, the concentrations of the fuel gas and the oxidizing gas are relatively high in the vicinity of the reactant gas outlet, and the reactant gas is consumed by the power generation reaction from the center to the outer periphery, and the fuel gas outlet 6 and the oxidant gas are oxidized. In the vicinity of the chemical gas outlet 7, the concentrations of the fuel gas and the oxidizing gas are relatively low. Then, the variation in the power generation output depending on the position inside the enlarged single cell 2 increases, and the output density per single cell 2 decreases,
The power generation output may be reduced. The present invention has been made in view of the above circumstances, and is a solid oxide fuel cell capable of uniformly supplying a reaction gas to a solid electrolyte body and making the distribution of power generation output within a single cell uniform. The purpose is to provide.

[0004]

In order to solve the above-mentioned problems and to achieve the above object, a solid oxide fuel cell according to the present invention according to the present invention comprises a solid electrolyte sandwiched between a positive electrode and a negative electrode. A single cell, a solid oxide fuel cell including a separator stacked on the positive electrode side and the negative electrode side of the single cell, a plurality of reaction gas supply holes provided on the surface of the separator, A reaction gas distribution pipe that is provided inside the separator and connects the opening on the separator side and the reaction gas supply hole, and the reaction gas supply hole on the surface of the separator facing the single cell. It is characterized in that it has a substantially spiral groove for reacting gas flow that spirals around the center.

[0005] According to the solid oxide fuel cell having the above structure, one or a plurality of spiral grooves for reactant gas flow spiraling around each reactant gas supply hole on the surface of the separator, and the separator are laminated. A flow path for a plurality of reaction gases is formed by the surface of the single cell thus formed. The reaction gas is supplied to each reaction gas supply hole from the opening on the side of the separator by, for example, a reaction gas circulation pipe inside the separator, and the reaction gas circulation groove is formed at each reaction gas supply hole from the reaction gas circulation pipe. And acts on the solid electrolyte of the single cell while being swirled smoothly along the spiral reaction gas flow groove.

In this case, since the reaction gas supplied through the reaction gas distribution pipe is distributed to a plurality of reaction gas supply holes on the surface of the separator, the concentration of the reaction gas is high over the entire power generation surface of the solid electrolyte. Can uniformly supply the reaction gas, which can contribute to the uniformization of the concentration distribution of the reaction gas. This eliminates the need to increase the flow rate of the reaction gas, for example, in order to prevent the concentration of the reaction gas from decreasing near the outlet of the reaction gas, and prevents the utilization rate of effectively using the reaction gas from decreasing. can do. Moreover, since the number of reaction gas supply holes is plural, the spiral reaction gas circulation groove has a compact shape, and the reaction gas supplied from the reaction gas supply hole is allowed to flow through the reaction gas circulation groove. An increase in the partial pressure (concentration) difference of the reaction gas before being discharged to the outside is suppressed. For this reason, the degree of the power generation reaction is suppressed from changing depending on the position, and it is possible to prevent a large variation in the power generation output.

Further, in the solid oxide fuel cell according to the present invention, the groove for reactant gas flow is provided in a region within a predetermined distance from the reactant gas supply hole, and the predetermined distance is equal to or smaller than the predetermined distance. It is characterized in that it is set according to the output density of the solid oxide fuel cell. According to the solid oxide fuel cell having the above-described structure, for example, the number of reaction gas supply holes and the number of turns of the reaction gas circulation groove can be maintained so that a high output density state can be maintained uniformly throughout the single cell. Set. For example, by increasing the number of reaction gas supply holes, a substantially spiral reaction gas circulation groove that spirals around these reaction gas supply holes becomes a compact shape, and the reaction gas supplied from the reaction gas supply hole is reduced. The difference between the partial pressures (concentrations) of the reaction gas is prevented from increasing during the time when the gas is caused to flow through the groove for flowing the reaction gas and discharged to the outside. Can be prevented.

Further, in the solid oxide fuel cell according to the present invention as set forth in claim 3, the separator is provided with the groove for flowing the reaction gas on two opposing surfaces, and the reaction gas is formed on one of the surfaces. The flow groove and the reaction gas flow groove on the other surface are formed in the same shape when viewed from both surfaces. According to the solid oxide fuel cell having the above structure, one of the reaction gas circulation grooves sandwiching the unit cell from both sides and the other of the reaction gas circulation grooves are arranged so as to intersect with each other.
For example, even when an internal pressure is generated due to a pressure difference between the reaction gas supplied to one of the reaction gas flow grooves and the reaction gas supplied to the other reaction gas flow groove, the solid electrolyte Can be prevented from being deformed or damaged.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid oxide fuel cell according to one embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side sectional view of a main part of a solid oxide fuel cell 10 according to an embodiment of the present invention, FIG. 2 is a side view of a separator 12 shown in FIG. 1, and FIG. FIG. 4 is a plan view of the separator 12 shown in FIG. 2 on the air electrode side, in which the flow path of the reaction gas in the inside is emphasized, and FIG. 5 is a plan view of FIG. FIG. 3 is a sectional view taken along line AA of the separator 12 shown in FIG. The solid oxide fuel cell 10 according to the present embodiment is formed, for example, in a substantially columnar appearance, and has a disk-shaped solid electrolyte plate 11A made of, for example, an oxide solid electrolyte such as zirconia.
And a positive electrode 11B and a negative electrode 11C on both sides of the solid electrolyte plate 11A, a separator 12, and a disc-shaped porous metal plate 13. The solid electrolyte plate 11A and the two electrodes 11B and 11C form one single cell 11, and the porous metal plate 13 is interposed between the single cell 11 and the separator 12, so that the single cell 11 and the separator 12
Are alternately stacked.

As shown in FIG. 2, a separator 12 made of, for example, stainless steel or the like is formed in a disk shape, and the surface 12A side (fuel electrode side) and the back surface 12B side (air electrode side) in the thickness direction of the separator 12. Side), for example, a fuel gas containing hydrogen is supplied to the front surface 12A side, and an oxidizing gas containing oxygen is supplied to the back surface 12B side. The separator 12 is composed of a substantially annular plate-shaped outer peripheral portion 14 having a predetermined length radially inward from the outer peripheral surface 12C, and a substantially disk-shaped inner peripheral portion 15. The inner peripheral portion 15 is formed thinner than the outer peripheral portion 14. That is, the surface 15A of the inner peripheral portion 15 is formed so as to be recessed one step from the surface 14A of the outer peripheral portion 14, and similarly, the back surface 15B of the inner peripheral portion 15 is formed so as to be recessed one step from the back surface 14B of the outer peripheral portion 14. A porous metal plate 13 is attached to the one-step recessed portion, and a laminated body including an inner peripheral portion 15 and two porous metal plates 13 sandwiching the inner peripheral portion 15 from both sides is provided. The thickness is equal to or slightly greater than the thickness of the outer peripheral portion 14.
4 is made thicker.

As shown in FIG. 3, the outer peripheral portion 14 is provided with, for example, one fuel gas supply hole 16a which is opened at the outer peripheral surface 12C and extends radially inside the fuel electrode side.
Further, as shown in FIG. 4, for example, one oxidizing gas supply hole 16 b that opens in the outer peripheral surface 12 </ b> C and extends radially inward on the air electrode side is provided with a fuel gas supply hole 16 a in the circumferential direction of the separator 12. It is arranged at a position shifted by 180 °.

As shown in FIG. 3, a plurality of (for example, six) fuel gas discharge nozzles 17 penetrating the outer peripheral portion 14 in the radial direction are provided at positions shifted toward the surface 14A inside the outer peripheral portion 14.
, 17a are arranged at predetermined intervals in the circumferential direction, and these fuel gas discharge nozzles 17a,.
7a can adjust the flow rate of the discharged fuel gas to a predetermined amount. Similarly, as shown in FIG. 4, a plurality of (for example, six) oxidizing gas discharge nozzles 17 b, which penetrate the outer peripheral portion 14 in the radial direction, at positions shifted toward the back surface 14 </ b> B inside the outer peripheral portion 14. , 17b are arranged at predetermined intervals in the circumferential direction.
, 17b can adjust the flow rate of the oxidizing gas to be discharged to a predetermined amount.

The fuel gas supply hole 16a is disposed at a substantially intermediate position between two fuel gas discharge nozzles 17a, 17a adjacent in the circumferential direction of the separator 12, and similarly,
The oxidizing gas supply holes 16b are provided between two oxidizing gas discharge nozzles 17b, 17 adjacent in the circumferential direction of the separator 12.
It is arranged at a substantially middle position of b. Although the radial length of the outer peripheral portion 14 is not particularly limited, the fuel gas discharged from the fuel gas discharge nozzle 17a and the oxidant gas discharged from the oxidant gas discharge nozzle 17b are separated. When a heat is generated due to a chemical reaction, the solid electrolyte plate 11 may be referred to, for example, by referring to the temperature characteristics of the solid electrolyte plate 11A.
A is set so that a large temperature difference does not occur between the outer peripheral side and the inner peripheral side of A.

A plurality (a) of a plurality of (a) are arranged at a predetermined distance on a center position on the surface 15A of the inner peripheral portion 15 and on a circumference of about (2/3) r with respect to the radius r of the inner peripheral portion 15 ( (For example, 6 positions), each having a bottom surface 18A, for example, a total of 7
, 18a are provided, and these bottom surfaces 18A,..., 18A are arranged at positions shifted toward the front surface 15A inside the inner peripheral portion 15, and similarly, the back surface 15B of the inner peripheral portion 15 is provided. The upper center position and a plurality of (for example, six) positions arranged at equal intervals at a predetermined distance on a circumference of about (2/3) r with respect to the radius r of the inner peripheral portion 15 have respective Bottom 1
.., 18b, for example, a total of seven recesses 18b,.
Are provided, and these bottom surfaces 18B are arranged at positions shifted inside the inner peripheral portion 15 toward the back surface 15B. That is, the concave portion 18a on the front surface 15A side and the concave portion 1 on the back surface 15B side
8b is prevented from communicating.

As shown in FIG. 4, for example, inside the inner peripheral portion 15 on the fuel electrode side, six concave portions 18a arranged on a circumference having a radius of about (2/3) r are provided. , 18a are connected to form an annular fuel gas pipe 19a. Further, a plurality of (for example, four) fuel gas radially extending from the central portion of the concave portion 18a is connected to the concave portion 18a arranged at the central position of the inner peripheral portion 15 and the annular fuel gas pipe 19a. Piping 19b, ..., 19b
Is disposed, and the annular fuel gas pipe 19a and the outer peripheral portion 14 are provided.
Gas pipe 19 connecting the fuel gas supply holes 16a
c is provided. Similarly, inside the inner peripheral portion 15 on the air electrode side, six concave portions 18b,..., 18b arranged on a circumference having a radius of about (2/3) r are connected to form a circle. An annular oxidant gas pipe 19d is provided. Further, a plurality of (for example, four) oxidants extending radially from the concave portion 18b at the center position so as to connect the concave portion 18b disposed at the center position of the inner peripheral portion 15 and the annular oxidant gas pipe 19d. A gas pipe 19e,..., 19e is provided, and the oxidant gas pipe 19 connects the annular fuel gas pipe 19d to the oxidant gas supply hole 16b of the outer peripheral portion 14.
f is provided.

Here, six recesses 18a,..., 18a arranged on a circumference having a radius of about (2/3) r are
A straight line connecting 8a and the center position of the inner peripheral portion 15 is disposed so as to pass through a substantially intermediate position between the two fuel gas discharge nozzles 17a, 17a of the outer peripheral portion 14 adjacent in the circumferential direction of the separator 12. That is, one of these straight lines passes through the fuel gas supply hole 16a. Further, four fuel gas pipes 19b,.
Are equiangular with each other in the circumferential direction of the separator 12, that is, 90 °.
And each fuel gas pipe 19
b is arranged so as to intersect with the direction in which the fuel gas pipe 19c extends. That is, four fuel gas pipes 1
Of the fuel gas pipes 9b,..., 19b, the two fuel gas pipes 19b, 19b, which form an angle of 180 °, have a radius of about (２).
r is connected to each of the recesses 18a on the circumference of r.
The fuel gas pipe 19c is connected to the fuel gas pipes 19b and 19b.
recesses 18a other than the respective recesses 18a, 18a to which b is connected
It is connected to the. Thereby, the fuel gas supply holes 16a
First, the fuel gas supplied from the fuel gas pipe 19c connected to the annular fuel gas pipe 19a is circulated in the annular fuel gas pipe 19a in an annular shape.
Are introduced into four fuel gas pipes 19b,..., 19b.

Similarly, a total of seven recesses 1 on the air electrode side are provided.
, 18b, the annular oxidizing gas pipe 19d, and the four oxidizing gas pipes 19e,..., 19e are a total of seven concave portions 18a,. The separators 12 are arranged symmetrically on the fuel electrode side and the air electrode side so as to face the gas pipe 19a and the four fuel gas pipes 19b,..., 19b. However, the oxidizing gas pipe 19f connected to the oxidizing gas supply hole 16b of the outer peripheral portion 14 is point-symmetric with respect to the center point of the separator 12 with respect to the fuel gas pipe 19c connected to the fuel gas supply hole 16a. Are located in

As shown in FIG. 3, on the surface 15A of the inner peripheral portion 15, a plurality of (for example, 16) fuel gas grooves 21a,...
1a is formed at a predetermined interval between the adjacent grooves 21a, 21a. One end of each fuel gas groove 21a is opened in the recess 18a, and the other end is coaxial with each recess 18a. Is connected to the annular annular groove 21b for fuel gas disposed in the fuel cell. In the recess 18a, the openings of the plurality of (for example, 16) fuel gas recesses 21a,..., 21a are arranged at predetermined intervals in the circumferential direction on the inner wall surface of the recess 18a. Further, the bottom surface 21A of the fuel gas groove 21a is disposed at a position shifted from the fuel gas pipe 19a toward the surface 15A in the thickness direction inside the inner peripheral portion 15.

Here, a plurality of (for example, seven) annular grooves 21b,..., 21b for fuel gas arranged coaxially with the recesses 18a,.
They are arranged so as to circumscribe each other, and are connected to each other at these circumscribed portions. That is, six fuel gas annular grooves 21b,..., 21b surround the outer circumference of the fuel gas annular groove 21b arranged coaxially with the center position on the surface 15A of the inner peripheral portion 15. Is arranged. Further, the fuel gas is inscribed in six annular grooves 21b,..., 21b for fuel gas arranged on a circumference having a radius of about (2/3) r, and connected to each other at these inscribed portions. The outer circumferential side fuel gas annular groove 21 c is formed on the surface 1 of the inner circumferential portion 15.
A plurality of fuel gas discharge nozzles 17a,..., 17a of the outer peripheral portion 14 are connected to the outer peripheral side annular groove 21c for fuel gas. In addition, on the surface 15A of the inner peripheral portion 15, the radially outer side of the annular fuel gas pipe 19a and the inner peripheral side of the outer peripheral fuel gas annular groove 21c in the radial direction of the separator 12. The plurality of annular grooves 21b are coaxially arranged at predetermined intervals in the radial direction between the adjacent annular grooves 21b for the fuel gas. , 21d are formed. And
These fuel gas arc-shaped concave grooves 21d,..., 21d are connected to adjacent fuel gas annular concave grooves 21b, 21b.

Similarly, as shown in FIG.
5, a plurality of (for example, 16) grooves 21e for oxidant gas extending spirally from each recess 18b.
, 21e are formed at a predetermined interval between the adjacent grooves 21e, 21e.
1e is open in the recess 18b and the other end is in each recess 1b.
8b is connected to an annular oxidant gas annular groove 21f arranged coaxially with 8b. And a plurality (for example, 7
, 21f) are connected to each other at circumscribed portions and have a radius of about (2/3).
, 21f arranged on the circumference of the circle r and connected to each other at the inscribed portions thereof at the outer peripheral side annular groove for oxidizing gas. Groove 21g
A plurality of oxidant gas discharge nozzles 1 on the outer peripheral portion 14 are provided in the outer peripheral side oxidant gas annular groove 21g.
, 17b are connected.

In the radial direction of the separator 12, the oxidizing gas is located on the outer circumferential side of the annular oxidizing gas pipe 19 a and on the inner circumferential side of the outer circumferential oxidizing gas annular groove 21 g. Between the annular grooves 21f for gas, a part of a plurality of annular grooves arranged coaxially with the annular groove 21g for outer peripheral oxidant gas and spaced apart from each other by a predetermined distance in the radial direction. Arc groove 21 for oxidizing gas
h,..., 21h are provided. The arc-shaped grooves 21h,..., 21h for the oxidizing gas are connected to adjacent annular grooves 21f, 21f for the oxidizing gas. Here, the groove 21a for the fuel gas on the front surface 15A side of the inner peripheral portion 15 and the groove 21e for the oxidizing gas on the back surface 15B side are formed, for example, in the same shape, and swirl in the same direction. It has been like that. That is, as shown in FIG. 3 and FIG.
When the fuel gas groove 21a as viewed from the A side is formed so as to be separated from the concave portion 18a while swirling clockwise, the oxidizing gas groove as viewed from the back surface 12B side of the separator 12. 21e is also formed so as to be separated from the concave portion 18b while swirling clockwise.

As shown in FIGS. 1 and 5, a disc-shaped porous member having the same outer diameter as the inner peripheral portion 15 is brought into surface contact with the front surface 15A and the rear surface 15B of the inner peripheral portion 15, respectively. Metal plates 13, 13 are disposed, and the back surface 13 </ b> B of the porous metal plate 13 and the grooves 21 a,
21b, 21c, and 21d define a fuel gas flow passage, and the back surface 13B of the porous metal plate 13 and the grooves 21e, 21f, 21g, and 21h for the oxidant gas define an oxidant gas flow passage. Have been. The porous metal plate 13
Is not particularly limited, but is preferably set to be equal to or less than half the depth of each of the grooves 21a and 21b. Here, the thickness of the porous metal plate 13 is set to be ,
When the depth is larger than half of the depth of the groove 21b,
a,..., 21h, the flow rate of the fuel gas or the oxidizing gas may decrease, and the power generation output may decrease. Also,
The outer diameter of the solid electrolyte plate 11 </ b> A is formed to be larger than the outer diameter of the porous metal plate 13.
The outer peripheral portion of the unit cells 11 stacked in 2 is brought into almost surface contact with the outer peripheral portion 14 of the separator 12 when the laminate is pressed and held from both sides, so that the inner peripheral portion of the unit cells 11 and the separator 12 15 to form an airtight closed space.

The groove width L and depth D of the fuel gas groove 21a and the oxidizing gas groove 21b are not particularly limited. The internal pressures of the fuel gas and the oxidizing gas are set to predetermined values, and the groove width L is preferably set to each of the bottom surfaces 21A,.
, 21D are equal to the area of the surface 15A of the inner peripheral portion 15, and the respective bottom surfaces 21 of the concave grooves 21e,.
.., 21H are set to be equal to the area of the back surface 15B. Here, when the groove width L is equal to
, 21D such that the total area of the bottom surfaces 21A,..., 21D of the grooves 21a,..., 21d is smaller than the area of the front surface 15A, or
, 21h, the total area of the bottom surfaces 21E,..., 21H is set to be small, so that the solid electrolyte plate 11A cannot be used effectively.
, 21D or the total area of the bottom surfaces 21E,..., 21H is set to be large.

For example, the diameter of the solid electrolyte plate 11A is set to about 1
In the case of 50 mm, the annular groove 21 b for fuel gas is used.
And the diameter of the annular groove 21f for the oxidizing gas is about 50 mm.
When the groove width L is 1 mm and the groove depth D is 1 mm, each of the 16 spiral fuel gas grooves 21a,.
When the grooves 1a and the oxidizing gas grooves 21e,..., 21e are formed, the fuel gas and the oxidizing gas go around the separator 12 by about half a turn, and the discharge nozzles 17a,
It is discharged from 17b. Here, both annular concave grooves 21b,
By setting the diameter of 21f to about 50 mm, the partial pressure (concentration) is increased until the fuel gas and the oxidizing gas supplied from the recesses 18a and 18b are discharged from the discharge nozzles 17a and 17b to the outside. 3.) The state where the output density is high in the entire region of the single cell 11 can be maintained by suppressing the difference from increasing.

The solid oxide fuel cell 10 according to the present embodiment has the above-described configuration. Next, the operation of the solid oxide fuel cell 10 will be described. First, a fuel gas supply hole 16a provided in the outer peripheral portion 14 of the separator 12
The fuel gas containing hydrogen is supplied to the fuel gas pipe 19c. The fuel gas supplied to the fuel gas pipe 19c is annularly circulated in the annular fuel gas pipe 19a, and is also supplied into each of the recesses 18a arranged on the circumference. The fuel gas introduced from the annular fuel gas pipe 19a into the four fuel gas pipes 19b,..., 19b is supplied to the recess 18a at the center. Then, the fuel gas supplied to each recess 18a is a spiral 1
The fuel gas is distributed to the six fuel gas grooves 21a,..., 21a.

On the other hand, an oxidizing gas containing oxygen is supplied to the oxidizing gas pipe 19f from an oxidizing gas supply hole 16b provided in the outer peripheral portion 14 of the separator 12. Then, the oxidizing gas is supplied from the oxidizing gas pipe 19f into the concave portion 18b on the back surface 15B side, and is distributed from the concave portions 18b to 16 spiral oxidizing gas concave grooves 21e,. You. Here, oxygen contained in the oxidizing gas moves in the solid electrolyte plate 11A from the positive electrode 11B side to the negative electrode 11C side in the form of oxygen ions in the form of oxygen ions, and chemically reacts with the hydrogen gas contained in the fuel gas on the negative electrode 11C side. react. The heat generated by the chemical reaction heats the solid oxide fuel cell 10 from the inside and generates a potential difference between the positive electrode 11B and the negative electrode 11C.

On the front surface 12A of the separator 12, water vapor generated by a chemical reaction with the unreacted fuel gas is discharged from the fuel gas discharge nozzle 17a. On the back surface 12B of the separator 12, the unreacted oxidizing gas is discharged. It is discharged from the oxidizing gas discharge nozzle 17b. Both nozzles 17
The fuel gas and the oxidant gas discharged from a and 17b are mixed, for example, outside the separator 12, and the solid oxide fuel cell 10 is heated from the outer peripheral side by heat generated by a chemical reaction.

As described above, according to the solid oxide fuel cell 10 of the present embodiment, the plurality of recesses 18a for distributing and supplying the fuel gas and the oxidizing gas to the fuel electrode side and the air electrode side of the separator 12 are provided. , 18b are provided, so that the fuel gas and the oxidizing gas can be supplied uniformly in a high concentration state over the entire power generation surface of the solid electrolyte plate 11A. As a result, it is possible to prevent a reduction in the utilization rate of effectively using the fuel gas and the oxidizing gas. Moreover, the spiral fuel gas grooves 21a,.
The oxidant gas grooves 21e,..., 21e have a compact shape, so that the fuel gas and the oxidant gas are not consumed until they are discharged to the outside, thereby preventing the concentration difference from increasing. This suppresses a change in the degree of the power generation reaction depending on the position, and prevents a large variation in the power generation output.

[0029]

As described above, according to the solid oxide fuel cell of the first aspect of the present invention, the reactive gas is uniformly supplied in a high concentration state over the entire power generation surface of the solid electrolyte. This can contribute to making the concentration distribution of the reaction gas uniform. As a result, it is possible to prevent the utilization rate of effectively using the reaction gas from decreasing.
In addition, it is possible to prevent the difference in the partial pressure (concentration) of the reaction gas from increasing between the time when the reaction gas supplied from the reaction gas supply hole flows through the groove for flowing the reaction gas and is discharged to the outside. I have. For this reason, the degree of the power generation reaction is suppressed from changing depending on the position, and it is possible to prevent a large variation in the power generation output. Furthermore, according to the solid oxide fuel cell of the present invention as set forth in claim 2, the reaction gas supplied from the reaction gas supply hole is caused to flow through the reaction gas flow groove and to be discharged to the outside. Therefore, the difference in the partial pressure (concentration) of the reaction gas is suppressed from increasing, and the output density can be made uniform. Furthermore, according to the solid oxide fuel cell of the present invention as set forth in claim 3, even when the internal pressure due to the pressure difference of the reaction gas between the fuel electrode side and the air electrode side of the separator is generated, the solid It is possible to prevent the electrolyte from being deformed or damaged.

[Brief description of the drawings]

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

FIG. 2 is a side view of the separator shown in FIG.

FIG. 3 is a plan view of the separator shown in FIG. 2 on the fuel electrode side.

FIG. 4 is a plan view of the separator shown in FIG. 2 on the air electrode side, in which a flow path of a reaction gas in the inside is emphasized.

FIG. 5 is a cross-sectional view taken along line AA of the separator shown in FIG.

FIG. 6 is a perspective view of a main part of a solid oxide fuel cell according to an example of the related art.

[Explanation of symbols]

Reference Signs List 10 solid electrolyte fuel cell 11 single cell 11A solid electrolyte plate (solid electrolyte) 12 separator 18a, 18b recess (reaction gas supply hole) 19a annular fuel gas pipe (reaction gas distribution pipe) 19b, 19c fuel gas pipe (Reaction gas distribution pipe) 19d Annular oxidant gas pipe (reaction gas distribution pipe) 19e, 19f Oxidant gas pipe (reaction gas distribution pipe) 21a Fuel gas groove (reaction gas distribution groove) ) 21e Groove for oxidant gas (groove for reactant gas flow)

Claims (3)

[Claims] 1. A solid oxide fuel cell comprising: a single cell made of a solid electrolyte sandwiched between a positive electrode and a negative electrode; and a separator laminated on the positive electrode side and the negative electrode side of the single cell. A plurality of reaction gas supply holes provided on the surface of the separator; a reaction gas distribution pipe provided inside the separator and connecting the opening on the separator side to the reaction gas supply hole; A solid oxide fuel cell, comprising: a substantially spiral groove for reactant gas flow spiraling around the reactant gas supply hole on the surface of the separator facing the cell. 2. The reaction gas circulation groove is provided in a region within a predetermined distance from the reaction gas supply hole, and the predetermined distance is set according to an output density of the solid oxide fuel cell. The solid oxide fuel cell according to claim 1, wherein: 3. The separator has the reaction gas flow groove on two opposing surfaces, the reaction gas flow groove on one surface, and the reaction gas flow groove on the other surface. 3. The solid oxide fuel cell according to claim 1, wherein the concave grooves are formed in the same shape as each other as viewed from both surface sides. 4.