JP2004146343A - Fuel cell and fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately perform a positioning operation of a plurality of electrolyte/electrode assemblies while arraying the assemblies and maintaining the desired power generating performance. <P>SOLUTION: A fuel cell 10 interposes a plurality of electrolyte/electrode assemblies 56 between separators 58. Each separator 58 has plates 60, 62 laminated to each other. A fuel gas channel 67 and an oxidant gas channel 82 are formed between the plates 60, 62. Three pieces of positioning protrusions 81 for positioning and disposing each of the electrolyte electrode assemblies 56 at prescribed positions are integrally formed on each plate 62. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell in which a disc-shaped electrolyte-electrode assembly composed of an electrolyte sandwiched between an anode electrode and a cathode electrode is disposed between separators, and a fuel cell stack for stacking the fuel cells.
[0002]
[Prior art]
In general, a solid oxide fuel cell (SOFC) uses an oxide ion conductor, for example, stabilized zirconia as an electrolyte, and has a single cell in which an anode electrode and a cathode electrode are provided on both sides of the electrolyte. (Electrolyte-electrode assembly) is sandwiched between separators (bipolar plates). This fuel cell is usually used as a fuel cell stack by continuously stacking a predetermined number of fuel cells.
[0003]
In this type of fuel cell, when an oxidizing gas, for example, a gas or air mainly containing oxygen (hereinafter, also referred to as an oxygen-containing gas) is supplied to the cathode electrode, the oxidizing gas is generated at the interface between the cathode electrode and the electrolyte. Oxygen in the oxidizing gas is ionized (O ^2- ), And oxygen ions move to the anode electrode side through the electrolyte. Since a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) or CO is supplied to the anode electrode, oxygen ions and hydrogen (or CO ) Reacts with water (or CO ₂ ) Is generated. The electrons generated during that time are taken out to an external circuit and used as DC electric energy.
[0004]
In general, a solid oxide fuel cell has a high operating temperature of 800 ° C. to 1000 ° C., so that internal reforming of fuel gas can be performed by using high-temperature exhaust heat. Turn to generate electricity. Therefore, the solid oxide fuel cell has the highest power generation efficiency among various types of fuel cells, and is desired to be used not only in combination with a gas turbine but also for in-vehicle use.
[0005]
By the way, since stabilized zirconia has low ionic conductivity, it is necessary to form the stabilized zirconia in a thin film shape in order to obtain a large current. However, it has been pointed out that the mechanical strength of the stabilized zirconia becomes weak, and as a result, it is impossible to increase the current of the solid oxide fuel cell.
[0006]
Therefore, for example, as disclosed in Patent Literature 1, a plurality of small-area single cells are arranged in a metal separator, and a fuel gas supply hole and an oxidizing gas supply hole are provided at a central portion of the single cell. A formed solid oxide fuel cell is known.
In Patent Document 1, it is possible to increase the total area of the cell in one plane, and to prevent the substrate from being damaged, thereby improving the reliability.
[0007]
However, according to Patent Document 1, when a plurality of unit cells are arranged on the separator, each unit cell cannot be positioned at a desired position. Therefore, it is actually difficult to accurately align the fuel gas supply manifold and the oxidant gas supply manifold provided on the separator with the fuel gas supply hole and the oxidant gas supply hole provided on each unit cell. Above, it is very difficult. As a result, there is a problem that the assembling work of the fuel cell becomes considerably complicated and time-consuming, and a reduction in workability is caused.
[0008]
Therefore, for example, as disclosed in Patent Document 2, a plate made of the same material as the gas separation plate is arranged outside at least one of the gas separation plates provided at the upper and lower ends of the battery stack, and each side of the battery stack is disposed. There is known an internal manifold type flat solid electrolyte fuel cell module in which an insulative side support member for supporting the fuel cell is extended for each side of the cell stack, and one end of the insulative side support member is joined to the plate.
[0009]
[Patent Document 1]
JP-A-6-310164 (paragraph [0032], FIG. 1)
[Patent Document 2]
JP-A-7-122287 (paragraph [0006], FIG. 1)
[0010]
[Problems to be solved by the invention]
However, Patent Document 2 described above is for preventing the cells and the gas separation plate from laterally shifting in the horizontal direction, and is not for positioning the cells.
Therefore, in Patent Literature 2, there is a problem that a plurality of cells cannot be accurately positioned and arranged within the separator surface.
[0011]
The present invention is intended to solve this kind of problem, while maintaining a desired power generation performance by arranging a plurality of electrolyte-electrode assemblies, and easily and accurately positioning the electrolyte-electrode assemblies. It is an object of the present invention to provide a fuel cell and a fuel cell stack capable of performing the above.
[0012]
[Means for Solving the Problems]
In the fuel cell according to the first aspect of the present invention, the plate constituting the separator is provided with a projection for positioning and arranging the plurality of electrolyte-electrode assemblies in the plane of the separator. Thereby, a plurality of electrolyte-electrode assemblies can be accurately and easily arranged within the separator surface, and effectively preventing displacement of the electrolyte-electrode assembly due to heat history or the like. It becomes possible. In addition, the electrolyte / electrode assembly can be easily and reliably arranged, the workability of assembling the fuel cell can be improved satisfactorily, and the power generation performance of each fuel cell can be effectively enhanced.
[0013]
In the fuel cell according to claim 2 of the present invention, the protrusion is provided at a position where one or more arrangement layers in which a plurality of electrolyte-electrode assemblies are arranged concentrically with the center of the separator can be formed. I have. For this reason, a large number of electrolyte-electrode assemblies are efficiently arranged in the separator surface, the amount of power generation per unit volume of the fuel cell is increased, and the high output of the fuel cell can be easily achieved with a compact configuration. Can be
[0014]
In addition, even when one of the plurality of electrolyte-electrode assemblies is disconnected, the remaining electrolyte-electrode assembly can conduct electricity. Therefore, the reliability of power generation can be improved.
[0015]
Further, in the fuel cell according to claim 3 of the present invention, the protrusions are arranged such that the electrolyte / electrode assembly of the inner peripheral side arrangement layer and the electrolyte / electrode assembly of the outer peripheral side arrangement layer are shifted in phase from each other. It is provided in the position where it is. As a result, the plurality of electrolyte-electrode assemblies can be arranged densely with each other, and the fuel cell can be reliably made compact while maintaining the desired power generation performance.
[0016]
Still further, in the fuel cell according to claim 4 of the present invention, three or more protrusions are provided corresponding to positions around each electrolyte / electrode assembly, and three or more of the electrolyte / electrode assemblies are provided. It is configured to be able to be accommodated between the above-mentioned protrusions in a non-contact state. For this reason, it is only necessary to dispose the electrolyte-electrode assembly between the three or more projections. This simplifies the assembly operation of the fuel cell at a stroke, and even if the electrolyte-electrode assembly thermally expands. The electrolyte-electrode assembly can be prevented from being damaged.
[0017]
In the fuel cell stack according to claim 5 of the present invention, the disc-shaped separator is provided with a projection for positioning and arranging a plurality of electrolyte-electrode assemblies in the plane of the separator, and the flange is provided with: A hole for inserting a stack tightening bolt is formed between the electrolyte-electrode assembly arranged at the outermost periphery. Therefore, the outer dimensions of the entire fuel cell stack are reduced, and the size of the fuel cell stack can be easily reduced.
[0018]
Furthermore, in the fuel cell stack according to claim 6 of the present invention, one or more arrangement layers in which a plurality of electrolyte-electrode assemblies are arranged are provided concentrically with the center of the separator. Thus, a plurality of electrolyte-electrode assemblies are arranged in the plane of the separator, and the output of the entire fuel cell stack can be easily increased with a compact configuration.
[0019]
Furthermore, in the fuel cell stack according to claim 7 of the present invention, three or more projections are provided corresponding to positions around each electrolyte-electrode assembly, and three or more projections are provided. It is configured to be able to be accommodated in a non-contact state between the plurality of protrusions or more. Therefore, assembling work of the entire fuel cell stack can be simplified at a stroke, and damage to the electrolyte / electrode assembly due to heat history or the like can be effectively prevented.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic perspective explanatory view of a fuel cell stack 12 in which a plurality of fuel cells 10 according to the first embodiment of the present invention are stacked, and FIG. 2 is a partial sectional explanatory view of the fuel cell stack 12. is there.
[0021]
The fuel cell 10 is a solid oxide fuel cell, and is used for various purposes, such as for installation and for in-vehicle use. In the first embodiment, as an application example of the fuel cell stack 12, for example, a configuration incorporated in a gas turbine 14 is shown in FIG. In FIG. 3, the fuel cell stack 12 has a shape different from that of the fuel cell stack 12 shown in FIGS. 1 and 2 in order to be incorporated into the gas turbine 14, but has a substantially identical configuration.
[0022]
A fuel cell stack 12 is built around a combustor 18 in a casing 16 constituting the gas turbine 14. After reacting from the center of the fuel cell stack 12 to a chamber 20 on the combustor 18 side, And the exhaust gas as the oxidant gas is discharged. The chamber 20 becomes narrower in the flow direction of the exhaust gas (the direction of the arrow X in FIG. 3), and the heat exchanger 22 is provided on the outer peripheral portion on the distal end side. A turbine (output turbine) 24 is disposed on the front end side of the chamber 20, and a compressor 26 and a generator 28 are coaxially connected to the turbine 24. The gas turbine 14 is configured to be axially symmetric as a whole.
[0023]
The discharge passage 30 of the turbine 24 communicates with a first passage 32 of the heat exchanger 22, and the supply passage 34 of the compressor 26 communicates with a second passage 36 of the heat exchanger 22. The second passage 36 communicates with the outer periphery of the fuel cell stack 12 via the heated air introduction passage 38.
[0024]
As shown in FIG. 1, the fuel cell stack 12 includes a plurality of fuel cells 10 having an outer peripheral corrugated disk shape stacked in the direction of arrow A, and flanges 40 a and 40 b disposed at both ends in the stacking direction. For example, they are integrally fastened and held via eight fastening bolts 42. At the center of the fuel cell stack 12, a circular fuel gas supply passage 44 is formed in the direction of arrow A with the flange 40a at the bottom (see FIG. 2).
[0025]
Around the fuel gas supply passage 44, a plurality of, for example, four exhaust gas passages 46 are formed in the arrow A direction with the flange 40b as a bottom. The flanges 40a, 40b and the end plates 97a, 97b are insulated by insulating plates 98a, 98b, and output terminals 48a, 48b are provided from the end plates 97a, 97b, respectively.
[0026]
As shown in FIGS. 4 and 5, the fuel cell 10 has a cathode electrode 52 and an anode electrode 54 provided on both sides of an electrolyte (electrolyte plate) 50 composed of an oxide ion conductor such as stabilized zirconia, for example. The electrolyte-electrode assembly 56 provided. The electrolyte electrode assembly 56 is formed in a relatively small disk shape.
[0027]
The fuel cell 10 is configured by disposing a pair of separators 58 with a plurality of, for example, 16 electrolyte / electrode assemblies 56 interposed therebetween. In the plane of the separator 58, an inner peripheral side array layer P1 in which eight electrolyte / electrode assemblies 56 are arranged concentrically with the fuel gas supply passage 44, which is the center of the separator 58, An outer peripheral side arrangement layer P2 on which eight electrolyte / electrode assemblies 56 are arranged is provided on the outer periphery of the side arrangement layer P1 (see FIG. 4).
[0028]
The separator 58 includes a plurality of, for example, two plates 60 and 62 stacked on each other. The plates 60 and 62 are made of, for example, a sheet metal such as a stainless alloy, and are provided with corrugated outer peripheral portions 60a and 62a, respectively (see FIGS. 7 and 8).
[0029]
As shown in FIGS. 6, 7, and 9, a rib portion 63a for providing the fuel gas supply passage 44 and the four exhaust gas passages 46 is formed in the center of the plate 60. On the plate 60, four inner projections 64 a circulating in the respective exhaust gas passages 46 are formed by bulging toward the plate 62 along the inner periphery from the rib 63 a.
A protruding portion 65 a protruding in a direction away from the plate 62 is formed around the fuel gas supply passage 44 of the plate 60.
[0030]
The plate 60 is provided with an outer protrusion 66a radially with respect to the fuel gas supply communication hole 44, and communicates with the fuel gas supply communication hole 44 between the inner protrusion 64a and the outer protrusion 66a. A fuel gas passage 67 is formed.
[0031]
The outer protrusion 66a is provided with a plurality of first walls 68a and second walls 70a alternately protruding a predetermined distance in a radially outward direction. As shown in FIG. 9, in the first wall portion 68a, an imaginary circle connecting the tips forms a center line of the inner peripheral side arrangement layer P1, and eight electrolyte / electrode junctions are formed along the inner peripheral side arrangement layer P1. The bodies 56 are arranged.
A second wall portion 70a is provided between the first wall portions 68a, and a center line of the outer peripheral side array layer P2 is formed by an imaginary circle passing through a tip of the second wall portion 70a. Eight electrolyte / electrode assemblies 56 are arranged along the center line of the outer peripheral side arrangement layer P2.
[0032]
Three oxidizing gas inlets 78 are formed around the distal ends of the first wall portion 68a and the second wall portion 70a, respectively, penetrating the plate 60. The plate 60 has a first boss 80 protruding toward each of the electrolyte-electrode assemblies 56 arranged along the inner peripheral side arrangement layer P1 and the outer peripheral side arrangement layer P2, and in contact with each electrolyte-electrode assembly 56. It is bulged.
[0033]
As shown in FIGS. 6, 8, and 9, near the inside of the corrugated outer portion 60a of the plate 60, the plate 60 has the same shape as the corrugated outer portion 60a, and projects in the direction away from the plate 62 to form a One round convex portion 83a is formed. The plate 60 has a plurality of outer circumferential protrusions 85a and inner circumferential protrusions 87a which are opposed to each other (or are displaced from each other) on both sides of the first circumferential protrusion 83a with a predetermined interval therebetween. Are provided.
[0034]
As shown in FIGS. 6, 7 and 10, a rib 63b is formed at the center of the plate 62 in opposition to the rib 63a of the plate 60, and four ribs projecting toward the plate 60 are formed. The inner protrusion 64b is bulged. A protruding portion 65 b protruding in a direction away from the plate 60 is formed around the fuel gas supply passage 44 of the plate 62.
[0035]
The plate 62 is provided with an outer protrusion 66b facing the outer protrusion 66a and protruding toward the plate 60. In the plates 60 and 62, a fuel gas passage 67 is formed in which the inner protrusions 64a and 64b and the outer protrusions 66a and 66b are in contact with each other and communicate with the fuel gas supply passage 44. The outer projection 66b is provided with a plurality of first wall portions 68b and second wall portions 70b alternately protruding by a predetermined distance in a radially outward direction.
[0036]
The plate 62 has a second boss portion 86 protruding toward each electrolyte-electrode assembly 56 arranged along the inner peripheral side arrangement layer P1 and the outer peripheral side arrangement layer P2, and in contact with each electrolyte-electrode assembly 56. It is bulged. Each dimension of the second boss portion 86 in the radial direction and the height direction is set smaller than that of the first boss portion 80. A fuel gas inlet 88 communicating with the fuel gas passage 67 is formed through the plate 62.
[0037]
The plate 62 is provided with positioning projections 81 for positioning and positioning the eight electrolyte / electrode assemblies 56 along the inner peripheral side arrangement layer P1 and the outer peripheral side arrangement layer P2. In the first embodiment, three or more positioning projections 81 are provided corresponding to positions around each electrolyte / electrode assembly 56, and three positioning projections 81 are provided, for example. It is set at a position that can be accommodated between the positioning projections 81 in a non-contact state. The positioning protrusion 81 is set to have a larger dimension in the height direction than the second boss 86 (see FIG. 6).
[0038]
As shown in FIGS. 6, 8 and 10, near the inner side of the outer peripheral portion 62a of the plate 62, the plate 62 has the same shape as that of the outer peripheral portion 62a, and projects in the direction away from the plate 60, and The two-turn convex portion 83b is formed. The plate 62 has a plurality of outer circumferential protrusions 85b and inner circumferential protrusions 87b which are opposed to each other (or are displaced from each other) with the second circumferential protrusion 83b interposed therebetween with a predetermined interval therebetween. Are formed one by one.
[0039]
Between the plate 60 and the plate 62, a fuel gas passage 67 is formed between the inner protrusions 64a, 64b and the outer protrusions 66a, 66b, and a fuel gas passage 67 is formed outside the outer protrusions 66a, 66b. An oxidizing gas passage 82 is formed corresponding to the two sides (see FIG. 11). The oxidizing gas passage 82 communicates with an oxidizing gas inlet 78 formed in the plate 60.
[0040]
As shown in FIG. 6, the separator 58 is provided with an insulating seal 90 for sealing the fuel gas supply passage 44. The insulating seal 90 is formed by, for example, disposing a ceramic plate material or spraying ceramic onto the convex portion 65a of the plate 60 or the convex portion 65b of the plate 62. The first and second orifices 83a and 83b of the plates 60 and 62 are formed by bulging in a direction away from each other, and the first and second orbits 83a and 83b are formed of ceramics or the like. Is provided by interposition or thermal spraying.
[0041]
As shown in FIGS. 5 and 6, the electrolyte / electrode assembly 56 is sandwiched between a plate 60 constituting one separator 58 and a plate 62 constituting the other separator 58. Specifically, the first boss 80 and the second boss 86 are bulged on the plates 60 and 62 facing each other with the electrolyte electrode assembly 56 interposed therebetween. The electrolyte / electrode assembly 56 is sandwiched between the second boss 86 and the second boss 86.
[0042]
As shown in FIG. 11, a fuel gas supply passage 94 communicating between a fuel gas passage 67 and a fuel gas inlet 88 is provided between the electrolyte electrode assembly 56 and a plate 62 constituting one separator 58. Is formed. An oxidizing gas supply passage 96 communicating from the oxidizing gas passage 82 through an oxidizing gas inlet 78 is formed between the electrolyte / electrode assembly 56 and the plate 60 constituting the other separator 58. .
The opening dimensions of the fuel gas supply passage 94 and the oxidizing gas supply passage 96 are set in accordance with the respective heights of the second boss 86 and the first boss 80. Since the flow rate of the fuel gas is smaller than the flow rate of the oxidizing gas, the size of the second boss portion 86 is set smaller than that of the first boss portion 80.
[0043]
As shown in FIG. 6, the fuel gas passage 67 communicates with the fuel gas supply passage 44 formed between the plates 60 and 62 constituting the same separator 58. The oxidizing gas passage 82 is formed on the same plane as the fuel gas passage 67, and is provided to the outside via the first and second orbital protruding portions 83 a and 83 b of the plates 60 and 62 constituting the same separator 58. It is open.
[0044]
Each separator 58 functions as a current collector when the first and second bosses 80 and 86 sandwich the electrolyte-electrode assembly 56 along the laminating direction, and the inner protrusions 64 a of the plates 60 and 62. , 64b and the outer projections 66a, 66b are in contact with each other, whereby the fuel cells 10 are connected in series along the direction of arrow A.
[0045]
As shown in FIGS. 1 and 2, the fuel cells 10 configured as described above are stacked in the direction of arrow A, and end plates 97a and 97b are arranged at both ends in the stacking direction. Outside the end plates 97a, 97b, flanges 40a, 40b are laminated with insulating plates 98a, 98b interposed. Holes 100a, 100b are formed in the flanges 40a, 40b corresponding to the portions where the corrugated outer peripheral portions 60a, 62a of the plates 60, 62 are curved inward. The fastening bolts 42 are inserted into the holes 100a and 100b, and the nuts 104 are screwed into ends of the holes 100a and 100b, whereby a desired tightening force is applied to the stacked fuel cells 10.
[0046]
The operation of the fuel cell stack 12 configured as described above will be described below.
[0047]
When assembling the fuel cell 10, first, the plates 60 and 62 constituting the separator 58 are joined. Specifically, as shown in FIG. 6, the inner projections 64a, 64b and the outer projections 66a, 66b integrally formed on the plates 60, 62 are fixed by brazing or the like, and a ring-shaped insulating seal is provided. 90 is provided on the plate 60 or the plate 62 around the fuel gas supply passage 44 by, for example, thermal spraying or the like. On the other hand, a wavy insulating seal 92 is provided, for example, by thermal spraying, on the first orifice 83a of the plate 60 or the second orifice 83b of the plate 62.
[0048]
Thus, a separator 58 is formed, and a fuel gas passage 67 and an oxidizing gas passage 82 are formed between the plates 60 and 62 on the same plane. Further, the fuel gas passage 67 communicates with the fuel gas supply passage 44, while the oxidizing gas passage 82 is open to the outside between the corrugated outer peripheral portions 60a and 62a.
[0049]
Next, the electrolyte electrode assembly 56 is sandwiched between the separators 58. As shown in FIG. 4 and FIG. 5, eight separators / electrode assemblies 56 are arranged on the surfaces facing each other, that is, between the plates 60 and 62, corresponding to the inner peripheral side arrangement layer P1. At the same time, eight electrolyte / electrode assemblies 56 are arranged along the outer peripheral side arrangement layer P2.
[0050]
At this time, three positioning projections 81 are provided at the positions where the respective electrolyte-electrode assemblies 56 are arranged, and the electrolyte-electrode assembly 56 is accommodated between the three positioning projections 81. You. First and second bosses 80 and 86 are formed in the positioning projection 81 so as to protrude in a direction approaching each other, and the first and second bosses 80 and 86 form an electrolyte-electrode assembly. 56 are pinched.
[0051]
For this reason, as shown in FIG. 11, between the cathode electrode 52 of the electrolyte electrode assembly 56 and the plate 60, the oxidizing gas supply passage communicating with the oxidizing gas passage 82 through the oxidizing gas inlet 78 is provided. A channel 96 is formed. On the other hand, between the anode electrode 54 of the electrolyte electrode assembly 56 and the plate 62, a fuel gas supply flow path 94 communicating with the fuel gas passage 67 via the fuel gas inlet 88 is formed. Further, a discharge passage 106 is formed between the separators 58 for mixing the reacted fuel gas and the oxidizing gas and leading the mixture to the fuel gas supply passage 44.
[0052]
The fuel cells 10 assembled as described above are stacked in the direction of arrow A, and the fuel cell stack 12 is assembled (see FIGS. 1 and 2).
[0053]
Thus, a fuel gas (for example, a hydrogen-containing gas) is supplied to the fuel gas supply communication hole 44 of the flange 40 b constituting the fuel cell stack 12, and the oxidant pressurized from the outer peripheral side of the fuel cell stack 12. An oxygen-containing gas (hereinafter, also referred to as air), which is a gas, is supplied. The fuel gas supplied to the fuel gas supply passage 44 is introduced into the fuel gas passage 67 in the separator 58 constituting each fuel cell 10 while moving in the stacking direction (the direction of arrow A) (see FIG. 6). .
[0054]
As shown in FIG. 5, the fuel gas moves along the first wall portions 68a, 68b and the second wall portions 70a, 70b that constitute the outer protrusions 66a, 66b, and the fuel gas inlets from the respective leading ends. The fuel gas is introduced into the fuel gas supply flow path 94 through the fuel gas supply passage 88. The fuel gas inlet 88 is provided corresponding to the center position of the anode electrode 54 of each electrolyte electrode assembly 56, and the fuel gas introduced into the fuel gas supply passage 94 is provided at the center of the anode electrode 54. It flows from the part toward the outer periphery (see FIG. 11).
[0055]
On the other hand, the oxidizing gas supplied from the outer peripheral side of each fuel cell 10 is supplied to the oxidizing gas passage 82 formed between the plates 60 and 62 of each separator 58.
The oxidizing gas supplied to the oxidizing gas passage 82 is introduced from the oxidizing gas inlet 78 into the oxidizing gas supply channel 96, and extends from the center of the cathode electrode 52 of the electrolyte electrode assembly 56 to the outer periphery thereof. (See FIGS. 5 and 11).
[0056]
Therefore, in each of the electrolyte electrode assemblies 56, the fuel gas is supplied from the center of the anode electrode 54 toward the outer periphery, and the oxidant gas is supplied from the center of the cathode electrode 52 toward the outer periphery. At this time, oxygen ions move to the anode electrode 54 through the electrolyte 50, and power is generated by a chemical reaction.
[0057]
Here, each electrolyte / electrode assembly 56 is sandwiched by first and second bosses 80 and 86, and the first and second bosses 80 and 86 function as current collectors. Therefore, the fuel cells 10 are electrically connected in series in the direction of arrow A (stacking direction), and can take output between the output terminals 48a and 48b. Further, even when one of the plurality of electrolyte / electrode assemblies 56 is disconnected, the remaining electrolyte / electrode assembly 56 can be energized, and the reliability of power generation can be improved. Can be improved.
[0058]
On the other hand, the reacted fuel gas and oxidizing gas (exhaust gas) that have moved to the outer periphery of each electrolyte-electrode assembly 56 move toward the center of the separator 58 via a discharge passage 106 formed between the separators 58. I do. Near the center of the separator 58, four exhaust gas passages 46 forming an exhaust gas manifold are formed, and exhaust gas is discharged from the exhaust gas passages 46 to the outside.
[0059]
In this case, in the first embodiment, a relatively small-diameter circular electrolyte-electrode assembly 56 is provided, and a plurality of, for example, 16 electrolyte-electrode assemblies 56 are arranged between the separators 58. Therefore, the thickness of the electrolyte / electrode assembly 56 can be reduced, the resistance polarization can be reduced, the temperature distribution can be reduced, and breakage due to thermal stress can be avoided. Therefore, the power generation performance of the fuel cell 10 can be effectively improved.
[0060]
Further, an inner peripheral side array layer P1 in which eight electrolyte / electrode assemblies 56 are arranged concentrically with the fuel gas supply passage 44, which is the center of the separator 58, and an outer peripheral side of the inner peripheral side array layer P1. And an outer peripheral side arrangement layer P2 in which eight electrolyte / electrode assemblies 56 are arranged. At this time, the electrolyte / electrode assembly 56 of the outer peripheral side array layer P2 is arranged out of phase with the electrolyte / electrode assembly 56 of the inner peripheral side array layer P1.
[0061]
More specifically, the electrolyte / electrode assemblies 56 of the outer peripheral side arrangement layer P2 are arranged corresponding to the electrolyte / electrode assemblies 56 of the inner peripheral side arrangement layer P1. Thereby, the plurality of electrolyte-electrode assemblies 56 can be densely arranged with each other, and an advantage that the entire fuel cell 10 can be easily made compact while maintaining desired power generation performance can be obtained.
[0062]
Further, in the first embodiment, the shape of the plates 60 and 62 constituting the separator 58 is set to the corrugated outer peripheral portions 60a and 62a, and the portion curved toward the center of the fuel gas supply passage 44, that is, the outer peripheral portion A fastening bolt 42 is provided at a portion corresponding to a portion between the electrolyte electrode assemblies 56 arranged in the side arrangement layer P2 (see FIG. 1). Therefore, the outer dimensions of the entire fuel cell stack 12 are effectively reduced, and the size of the fuel cell stack 12 can be easily reduced.
[0063]
Further, as shown in FIGS. 6 and 11, three positioning projections 81 are integrally formed on the plate 62 constituting the separator 58, respectively, corresponding to the positions of the respective electrolyte-electrode assemblies 56. ing. Accordingly, the electrolyte-electrode assembly 56 can be accurately arranged at a desired position of the separator 58 only by disposing the electrolyte-electrode assembly 56 between the three positioning projections 81.
[0064]
Thereby, particularly when the plurality of electrolyte-electrode assemblies 56 are arranged on the separator 58, the positioning accuracy of the electrolyte-electrode assemblies 56 is easily and reliably performed, and the workability of assembling the fuel cell 10 is greatly improved. The effect is obtained. Moreover, since the positioning accuracy of the electrolyte electrode assembly 56 is improved, the fuel gas and the oxidizing gas can be accurately supplied to the center of the electrolyte electrode assembly 56. Therefore, the power generation performance of each fuel cell 10 can be improved satisfactorily.
[0065]
Furthermore, the three positioning projections 81 are set at positions where the electrolyte electrode assembly 56 can be accommodated in a non-contact state. Therefore, even if thermal expansion occurs in the electrolyte / electrode assembly 56 and the separator 58, the electrolyte / electrode assembly 56 does not come into contact with the positioning projection 81 and receives stress, and the electrolyte / electrode assembly 56 It is possible to effectively avoid damage and misalignment.
[0066]
In addition, the positioning projection 81 is integrally formed on the plate 62 by press molding or the like. Accordingly, there is no need to provide a special positioning material for positioning each electrolyte-electrode assembly 56, and the number of parts can be effectively reduced, and the weight of the separator 58 and the configuration of the separator 58 can be simplified. become. For this reason, there is an advantage that the fuel cell 10 having excellent assembling workability and maintaining a stable power generation function can be reliably assembled.
[0067]
Since the positioning projection 81 is provided on the fuel gas side where the passage height is low, that is, on the second boss 86 side, the molding height of the positioning projection 81 can be set low.
[0068]
Next, the operation when the fuel cell stack 12 is incorporated in the gas turbine 14 shown in FIG. 3 will be schematically described.
[0069]
As shown in FIG. 3, in the gas turbine 14, the combustor 18 is driven at the time of starting, the turbine 24 is rotated, and the compressor 26 and the power generator 28 are driven. The outside air is introduced into the supply passage 34 by the driving of the compressor 26, and the air having a high pressure and a predetermined temperature (for example, 200 ° C.) is sent to the second passage 36 of the heat exchanger 22.
[0070]
The first passage 32 of the heat exchanger 22 is supplied with a high-temperature exhaust gas as a fuel gas and an oxidant gas after the reaction, and the air introduced into the second passage 36 of the heat exchanger 22 is heated. You. The heated air is introduced into the outer peripheral portion of each fuel cell 10 constituting the fuel cell stack 12 through the heated air introduction passage 38. For this reason, power is generated in the fuel cell 10, and the exhaust gas as the fuel gas and the oxidant gas after the reaction is discharged to the chamber 20 in the casing 16.
[0071]
At that time, the exhaust gas discharged from the solid electrolyte type fuel cell 10 has a high temperature of 800 ° C. to 1000 ° C., and the exhaust gas rotates the turbine 24 to generate power by the power generator 28 and heat exchange. The external air sent to the container 22 and sucked can be heated. Accordingly, it is not necessary to use the combustor 18 and the turbine 24 can be rotated using the exhaust gas discharged from the fuel cell stack 12.
[0072]
In addition, since the exhaust gas has a high temperature of 800 ° C. to 1000 ° C., internal reforming of the fuel supplied to the fuel cell stack 12 can be performed. Therefore, internal reforming can be performed using various fuels such as natural gas, butane, and gasoline as the fuel.
[0073]
FIG. 12 is a cross-sectional explanatory view showing a schematic configuration of a gas turbine 120 according to a second embodiment to which a relatively small fuel cell stack 12a is applied, and FIG. 13 is a front explanatory view of the gas turbine 120. is there. Note that the same components as those of the gas turbine 14 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the third embodiment described below, the detailed description is also omitted.
[0074]
Eight fuel cell stacks 12 a are mounted around the combustor 18 at intervals of 45 ° around the outer periphery of a casing 122 constituting the gas turbine 120. Each fuel cell stack 12a is surrounded by a housing 124, and a heated air introduction passage 126 is formed in the housing 124.
[0075]
In the gas turbine 120 configured as described above, eight fuel cell stacks 12a are mounted on the outer periphery of the casing 122 at intervals of 45 °. For this reason, the effect that the electromotive force increases and the overall length of the gas turbine 120 is effectively shortened is obtained.
[0076]
FIG. 14 is a cross-sectional explanatory view showing a schematic configuration of a gas turbine 130 according to a third embodiment to which a relatively large fuel cell stack 12b is applied, and FIG. 15 is a front explanatory view of the gas turbine 130. is there.
[0077]
On the outer circumference of the casing 132 constituting the gas turbine 130, four fuel cell stacks 12b are provided around the combustor 18 on two circumferences separated by a predetermined distance in the axial direction (arrow X direction), respectively. ° Mounted at intervals. The phases of the fuel cell stacks 12b mounted on each circumference are shifted from each other by 45 ° so that the fuel cell stacks 12b do not overlap each other. Each fuel cell stack 12b is surrounded by a housing 134, and a heating air introduction passage 136 is formed in the housing 134.
[0078]
In the gas turbine 130 configured as described above, four fuel cell stacks 12b are mounted on the outer periphery of the casing 132 at intervals of 90 ° and shifted by 45 ° from each other. For this reason, a large number (eight) of relatively large fuel cell stacks 12b can be arranged, improving the power generation efficiency, and effectively reducing the outer peripheral dimensions of the entire gas turbine 130, thereby reducing the size of the gas turbine 130. The effect that it becomes possible to achieve the effect is obtained.
[0079]
In the first to third embodiments, the case where the fuel cell stacks 12, 12a, and 12b are used by being incorporated into the gas turbines 14, 120, and 130 has been described. However, the present invention is not limited to this. It is also possible to use the battery stacks 12, 12a and 12b for vehicle use.
[0080]
【The invention's effect】
In the fuel cell and the fuel cell stack according to the present invention, the plate constituting the separator is provided with a projection for positioning and arranging the plurality of electrolyte / electrode assemblies in the plane of the separator. Thereby, in the separator surface, a plurality of electrolyte-electrode assemblies can be accurately arranged, and effectively preventing the electrolyte-electrode assembly from being displaced due to heat history or the like. Will be possible. In addition, the electrolyte / electrode assembly can be easily and reliably arranged, and the workability of assembling the fuel cell is improved.
[Brief description of the drawings]
FIG. 1 is a schematic perspective explanatory view of a fuel cell stack in which a plurality of fuel cells according to a first embodiment of the present invention are stacked.
FIG. 2 is a partially sectional explanatory view of the fuel cell stack.
FIG. 3 is an explanatory sectional view showing a schematic configuration of a gas turbine incorporating the fuel cell stack.
FIG. 4 is an exploded perspective view of the fuel cell.
FIG. 5 is a partially exploded perspective view showing the operation of the fuel cell.
FIG. 6 is a partially omitted cross-sectional view of the fuel cell stack.
FIG. 7 is an exploded perspective view of a separator constituting the fuel cell.
FIG. 8 is a partially enlarged exploded perspective view of the fuel cell.
FIG. 9 is an explanatory front view of one plate constituting the separator.
FIG. 10 is an explanatory front view of the other plate constituting the separator.
FIG. 11 is an explanatory diagram of the operation of the fuel cell.
FIG. 12 is an explanatory sectional view showing a schematic configuration of a gas turbine according to a second embodiment to which a relatively small fuel cell stack is applied.
FIG. 13 is an explanatory front view of the gas turbine.
FIG. 14 is an explanatory sectional view showing a schematic configuration of a gas turbine according to a third embodiment to which a relatively large fuel cell stack is applied.
FIG. 15 is an explanatory front view of the gas turbine.
[Explanation of symbols]
10: fuel cell 12, 12a, 12b: fuel cell stack
14, 120, 130 ... gas turbine
16, 122, 132 ... casing
18: Combustor 22: Heat exchanger
24 Turbine 26 Compressor
28: generator 38, 126, 136: heated air introduction passage
40a, 40b: flange 44: fuel gas supply passage
46: exhaust gas passage 50: electrolyte
52: cathode electrode 54: anode electrode
56: Electrolyte-electrode assembly 58: Separator
60, 62: plate 60a, 62a: corrugated outer periphery
64a, 64b ... inner protrusion 65a, 65b ... protrusion
66a, 66b: outer projection 67: fuel gas passage
78: oxidizing gas inlet 80, 86: boss
81: Positioning projection 82: Oxidizing gas passage
83a, 83b ... orbital protrusion 88 ... fuel gas inlet
90, 92: insulating seal 94: fuel gas supply channel
96 oxidant gas supply passage

Claims (7)

An electrolyte-electrode assembly constituted by sandwiching an electrolyte between an anode electrode and a cathode electrode is a fuel cell disposed between separators,
The separator includes a plurality of plates stacked on each other, a fuel gas passage for supplying a fuel gas to the anode electrode, and an oxidizing gas for supplying an oxidant gas to the cathode electrode, between the plates. While the agent gas passage is formed,
A fuel cell, characterized in that at least one plate is provided with a projection for positioning and arranging a plurality of the electrolyte / electrode assemblies in the plane of the separator. 2. The fuel cell according to claim 1, wherein the protrusion is provided at a position where one or more arrangement layers in which the plurality of electrolyte-electrode assemblies are arranged concentrically with the center of the separator can be formed. 3. And the fuel cell. 3. The fuel cell according to claim 2, wherein the protrusion is located at a position where the electrolyte / electrode assembly of the inner peripheral side arrangement layer and the electrolyte / electrode assembly of the outer peripheral side arrangement layer are arranged out of phase with each other. A fuel cell, comprising: a fuel cell; 4. The fuel cell according to claim 1, wherein the protrusions are provided at three or more positions corresponding to positions around each of the electrolyte-electrode assemblies, and the electrolyte-electrode assembly is provided. 5. Is configured to be accommodated in a non-contact state between three or more of the protrusions. A fuel cell in which a disc-shaped electrolyte / electrode assembly composed of an electrolyte sandwiched between an anode electrode and a cathode electrode is disposed between disc-shaped separators, and a plurality of the fuel cells are stacked and both ends in the stacking direction. A fuel cell stack, wherein a flange is disposed on the fuel cell stack,
The separator is provided with protrusions for positioning and arranging the plurality of electrolyte-electrode assemblies in the plane of the separator,
A fuel cell stack, wherein a hole is formed in the flange corresponding to the space between the electrolyte-electrode assembly disposed on the outermost periphery, for inserting a stack fastening bolt. 6. The fuel cell stack according to claim 5, wherein the protrusion is provided at a position where one or more arrangement layers in which the plurality of electrolyte-electrode assemblies are arranged concentrically with the center of the separator can be formed. Characteristic fuel cell stack. 7. The fuel cell stack according to claim 5, wherein three or more protrusions are provided corresponding to positions around each electrolyte-electrode assembly, and three or more electrolyte-electrode assemblies are provided. 8. A fuel cell stack, wherein the fuel cell stack is configured to be accommodated in a non-contact state between the protrusions.

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