JP3487606B2 - Solid oxide fuel cell power reactor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell power generator using a solid electrolyte. 2. Description of the Related Art A solid oxide fuel cell is an air electrode made of, for example, a perovskite-type lanthanum-based composite oxide with a solid electrolyte such as yttria-stabilized zirconia (YSZ) or calcia-stabilized zirconia (CSZ) interposed therebetween. And a fuel electrode mainly composed of nickel or the like, and an electromotive force is obtained by electrochemically reacting air flowing toward each of the electrodes with a fuel gas through a solid electrolyte. In this type of fuel cell, the fuel gas flow path and the air flow path need to be separated in an airtight state.
For example, it is known that a solid electrolyte is formed in a cylindrical shape, and electric power is obtained by a cylindrical single cell provided with the electrodes on the inner and outer surfaces. In this case, since the power obtained by the single cell is small, a plurality of cylindrical cell stacks having one or two or more single cells are arranged in the casing, and these are electrically connected in series or in series / parallel to reduce the power. There are many power reactors that have been obtained. FIG. 4 is a sectional view of a power generating furnace in which a plurality of cell stacks each having one single cell are housed. In the figure, reference numeral 1 denotes a power generating furnace casing which forms the outer surface of the power generating furnace. An air partition plate 2 and an air gas partition plate 3 are fixed inside the power generating furnace casing 1. Thus, three chambers are vertically arranged, that is, a first air chamber 4, a second air chamber 5, and a fuel gas chamber 6.
Is divided into The first air chamber 4 is provided with an air supply hole 4a for supplying air for power generation.
Is provided with an air discharge hole 5a for discharging generated air, and a fuel gas chamber 6 is provided with a fuel gas supply hole 6a for supplying fuel gas for power generation and a fuel gas chamber 6 for discharging fuel gas used for power generation. A fuel gas discharge hole 6b is provided. In FIG. 1, reference numeral 7 denotes a cell stack positioned vertically in a fuel gas chamber 6. The cell stack 7 has an air electrode on the inner surface of a cylindrical solid electrolyte and a fuel electrode on the outer surface. The formed single cell 8 of a cylindrical shape and the single cell 8 formed on the upper end side of the single cell 8 are constituted by an insulated guide portion 9. It has a closed shape. The lower end of the cell stack 7 is supported on a bottom plate 1 a forming the fuel gas chamber 6 of the power generator casing 1, and the upper open end side guide 9 has a hole formed in the air gas partition plate 3. It is positioned so as to penetrate the portion 3a and face the second air chamber 5 side. An air introduction pipe 10 extending downward through the air partition plate 2 is inserted into the cell stack 7 up to the vicinity of its closed end.
An air passage 11 is formed between the fuel cell 0 and the cell stack 7, and a fuel gas passage 12 is formed near the outer peripheral surface of the cell stack 7. Then, the air supplied from the air supply hole 4a into the first air chamber 4 is introduced into the air flow path 11 in the cell stack 7 through the air introduction pipe 10, and the fuel gas supply hole 6a
When the fuel gas supplied from the fuel cell into the fuel gas chamber 6 is introduced into the fuel gas flow path 12 outside the cell stack 7, the single cell 8
The oxygen gas in the air and the hydrogen gas in the fuel gas electrochemically react with each other via the solid electrolyte therein to generate an electromotive force in the single cell 8, and desired electric power is generated from the plurality of cell stacks 7. Taken out. After the generated air is collected in the second air chamber 5, it is discharged to the outside through the air discharge hole 5 a, and the used fuel gas is discharged through the fuel gas discharge hole 6 b of the fuel gas chamber 6. It is discharged outside. The electrochemical reaction via the solid electrolyte is performed at a high temperature of about 1000 ° C., and the cell stack 7 is mainly composed of a perovskite-type lanthanum-based composite oxide or YSZ. While the power generation furnace casing 1 is mainly formed of a metal such as Ni and has a different coefficient of thermal expansion, the cell stack 7 and the power generation furnace casing 1 have different thermal expansion rates. Differences in volume occur. For this reason, the diameter of the hole portion 3a of the air partition plate 2 is made sufficiently larger than the outer diameter of the guide portion 9 of the cell stack 7, so that the cell stack 7 and the power reactor casing 1 can be freely moved at the start-up of the power reactor. It can be thermally expanded. Therefore, the cell stack 7 has a one-end supporting structure supported only on the lower end side by the power generating furnace casing 1 side, and there is an inconvenience that a large stress is generated at the lower end portion. Therefore, the strength of the material is about 1000
At a high temperature of ℃, there is a problem that the closed end side of the cell stack 7 is deformed or cracked. Further, since there is a gap between the guide portion 9 of the cell stack 7 and the air gas partition plate 3, for example, fuel gas on the high pressure side leaks from the gap into the second air chamber 5 side, and hydrogen in the fuel gas The gas may be burned near the guide portion 9 of the cell stack 7, and the combustion heat may destroy the cell stack 7 and the like. On the other hand, as shown in FIG. 5, the periphery of the guide portion 9 of the cell stack 7 inserted into the hole 3a of the air gas partition plate 3 is fixedly supported by the air gas partition plate 3 without any gap. At the same time, if the lower end of the cell stack 7 is separated from the bottom plate 1a of the power generation furnace casing 1 so that the cell stack 7 can be thermally expanded freely, the above-described leakage of the fuel gas does not occur. However, also in this case, since the cell stack 7 has one end supporting structure in which only the upper end side is supported by the power generator casing 1 via the air gas partition plate 3, there is a disadvantage that a large stress is generated at the upper end. there were. The present invention has been made in view of the above circumstances, and a solid oxide fuel cell capable of supporting a cell stack positioned in a vertical direction without generating a large stress in a power generation furnace casing without generating a large stress. It is intended to provide a power generation furnace. [0010] In order to achieve the above object, the present invention has a single cell formed by sandwiching a solid electrolyte between a pair of electrodes, and has air and fuel gas inside and outside thereof. DOO cylindrical cell Rusutakku where Ru is washed away, in a power reactor the solid electrolyte fuel cell power generation furnaces in the power reactor casing which forms the outer surface are supported by the power reactor casing in a state of being positioned in the vertical direction The two ends of the cell stack are fixed to a support member fixed in a power reactor casing.
Is constant, and, together when being supported, the power reactor around the casing between the support member, together with the bellows to absorb the thermal expansion difference between this power reactor casing the cell stack is provided, and the bellows The power generation furnace casing is made of the same material. [0011] [action] cylindrical cell Rusutakku becomes the ends support for its opposite ends is supported by the supporting support member which is secured to the internal power reactor <br/> casings grayed, large stress to the cell stack Is supported without causing In this case, the cell stack because it is positioned in the vertical direction, the thermal expansion difference between the cell stack and the power reactor casing occurs be fixed to supporting lifting the ends of the cell stack to the support member, a large thereto Although thermal stress may occur, this thermal expansion difference is absorbed by expansion and contraction means provided around the power generation furnace casing between the support members, so that no large thermal stress occurs in the cell stack and the power generation furnace casing. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a solid oxide fuel cell type power reactor according to one embodiment of the present invention. The basic configuration of the power reactor is the same as that of the power reactor shown in FIG. That is, in this power generation furnace, a plurality of cell stacks 7 in which single cells 8 are formed have their lower closed ends fixed on the bottom plate 1a of the power generation furnace casing 1 mainly composed of a metal such as Ni. It is positioned in the fuel gas chamber 6 in a state where the upper guide portion 9 side is penetrated through the air gas partition plate 3. Then, an air introduction pipe 10 whose upper end penetrates through the air partition plate 2 and opens to the first air chamber 4 is inserted into the cell stack 7 through the second air chamber 5, and the air introduction pipe 10 and the cell An air passage 11 is formed between the stacks 7, and a fuel gas passage 12 is formed in the fuel gas chamber 6 near the outer periphery of the cell stack 7. The first air chamber 4 has an air supply hole 4a,
The second air chamber 5 has an air discharge hole 5a, and the fuel gas chamber 6 has a fuel gas supply hole 6a and a fuel gas discharge hole 6b. FIG. 2 shows a cross section of a single cell 8 of the cell stack 7. The single cell 8 is formed on a cylindrical solid electrolyte 8a made of, for example, YSZ and an inner surface of the solid electrolyte 8a. A cylindrical air electrode 8b made of a lanthanum-based composite oxide, and a solid electrolyte 8
a fuel electrode 8c formed on the outer surface side of FIG. 1a and made of, for example, Ni—ZrO ₂ cermet;
b and protrudes outward from the fuel electrode 8c, and is composed of a vertically elongated interconnector 8d made of, for example, a perovskite-type lanthanum-based composite oxide. In addition, since the air electrode 8b also has a role of a support tube of the single cell 8, its thickness is larger than that of the others. In this case, the interconnectors 8d and the air electrodes 8b of the unit cells 8 of the cell stack 7 adjacent to each other in the left-right direction are electrically connected in series via the conductive felt 13 and are adjacent in the front-rear direction. The fuel cells 8c of the unit cells 8 of the cell stack 7 are electrically connected in parallel via the conductive felt 13, and the unit cells 8 of the plurality of cell stacks 7 are connected in series and parallel as a whole. It has a configuration. In this embodiment, the upper and lower ends of the cell stack 7 are fixed and supported by the power generator casing 1 itself and a supporting member supported by the same. That is, the upper guide portion 9 of the cell stack 7 is supported in a state where the outer peripheral surface side thereof is fixed to the air gas partition plate 3 supported by the power generator casing 1 without any gap, and the lower guide portion 9 of the cell stack 7 is closed. The closed end is supported by being fixed to a bottom plate 1a which is a part of the power reactor casing 1. Around the power generator casing 1 between the air gas partition plate 3 as the upper and lower support members of the cell stack 7 and the bottom plate 1a, the thermal expansion of the cell stack 7 during power generation and the air gas partition plate 3 A metal bellows 14 having excellent heat resistance is attached as expansion and contraction means for absorbing the difference between the thermal expansion amount of the power generation furnace casing 1 and the bottom plate 1a.
The bellows 14 is made of, for example, the same material as the power generating furnace casing 1 and has a gas-tight structure in which gas leakage does not occur. Therefore, even if the temperature of the cell stack 7 and the fuel gas chamber 6 becomes high during power generation and the strength of the cell stack 7 and the like is reduced, the cell stack 7 is uniformly supported at two upper and lower locations. The load applied to the support of the cell stack 7 is reduced by half, and no large stress is generated in the cell stack 7. For this reason, no crack is generated in the fixed portion between the guide portion 9 of the cell stack 7 and the air partition plate 2, and no deformation occurs in the closed portion of the cell stack 7. The cell stack 7 is mainly made of perovskite-type lanthanum-based composite oxide or ceramics such as YSZ, and has a lower coefficient of thermal expansion than that of the power generator casing 1 mainly made of metal such as Ni. Since the cell stack 7 is small, a difference in thermal expansion occurs between the cell stack 7 and the power generation furnace casing 1. Since this difference in thermal expansion is absorbed by the bellows 14, both ends of the cell stack 7 are fixed to the power generation furnace casing 1. However, no thermal stress is generated in the cell stack 7. In the above embodiment, the cell stack 7 is 1
Although the description has been given of the case where the fuel cell chamber 8 includes a plurality of single cells 8, a plurality of so-called vertical stripe-shaped cell stacks 7 each having a plurality of cylindrical single cells 8 in the vertical direction are arranged in the fuel gas chamber 6. Is also good. For example, when the power generation furnace casing 1 is made of a material whose coefficient of thermal expansion is smaller than that of the cell stack 7, the closed end side of the cell stack 7 needs to be fixed to the bottom plate 1a of the power generation furnace casing 1. Instead, the closed end side of the cell stack 7 may be placed on the bottom plate 1a of the power generating furnace casing 1, and the cell stack 7 may be supported by the bottom plate 1a. FIG. 3 is a sectional view of a solid oxide fuel cell type power generating furnace according to another embodiment of the present invention. In this power generation furnace, the inside of a power generation furnace casing 21 mainly made of a metal such as Ni is divided into a first air chamber 24 and a fuel by a first air gas partition plate 22 and a second air gas partition plate 23 fixed thereto. The fuel cell chamber 25 is divided into a gas chamber 25 and a second air chamber 26, and a plurality of cylindrical cell stacks 27 each having a plurality of single cells 28 formed therein are vertically positioned in the fuel gas chamber 25. The cell stack 27 is composed of a plurality of cylindrical single cells 28 provided independently of each other, and guide portions 29 provided on both sides of the plurality of single cells 28. Guide portion 29 penetrates the first and second air gas partition plates 22 and 23, and the outer peripheral surface side of the guide portion 29 is fixed to the first and second air gas partition plates 22 and 23 without any gap. Supported. The air flow path 3 is provided in the cell stack 27.
0 is formed, and a fuel gas flow path 31 is formed near the outer peripheral surface of the cell stack 27. The single cell 28 has an air electrode and a fuel electrode formed on the inner and outer surfaces of a cylindrical solid electrolyte, and an interconnector for conducting to the air electrode is protruded outside the fuel electrode. The materials and the shapes of the components are the same as those of the single cell shown in FIG. In addition, the adjacent cell stack 2
7 are connected in series and parallel to each other via conductive felt. Further, N around the power generator casing 21 between the first air gas partition plate 22 and the second air gas partition plate 23
A bellows 32 which is a gas-tight expansion / contraction means composed of a cell stack 27 and the first and second air gas partition plates 2 is attached.
The difference in thermal expansion between the power generation furnace casing 21 and the power generation furnace casing 23 is absorbed. 24a is an air supply hole,
25a is a fuel gas supply hole, 25b is a fuel gas discharge hole, 2
6a is an air discharge hole. Therefore, also in this power generating furnace, the air supplied to the first air chamber 24 through the air supply hole 24a is introduced into the air flow path 30 in the cell stack 27, and the fuel gas supply hole 25a is When the fuel gas supplied to the fuel gas chamber 25 via the fuel cell is introduced into the fuel gas passage 31 near the outer peripheral surface of the cell stack 27, the oxygen gas in the air and the hydrogen gas in the fuel gas are converted into a single cell 28. Reacts electrochemically through the solid electrolyte, and an electromotive force is generated in each single cell 28 in the cell stack 27. Then, for the entire power generating furnace, electric power corresponding to the number of cell stacks 27 is taken out for each single cell 28 of the cell stack 27. After the generated air is collected in the second air chamber 26, it is discharged to the outside through the air discharge holes 26a, and the generated fuel gas is discharged to the outside through the fuel gas discharge holes 25b. In this case, since the cell stack 27 is evenly supported at the two upper and lower portions, the force applied to the supporting portion of the cell stack 27 is reduced by half, so that no large stress is generated in the cell stack 27 and the like, and Of the first air chamber 24 and the fuel gas chamber 25, and between the second air chamber 26 and the fuel gas chamber 25, There is no leakage of air or fuel gas. Further, in this case, a difference in thermal expansion occurs between the cell stack 27 and the power generator casing 21 between the first and second air gas partition plates 22 and 23. Since the difference in thermal expansion is absorbed by the bellows 32, No large thermal stress is generated in the cell stack 27 or the like. Each single cell 28 in the cell stack 27
May be connected to each unit cell 28 in another cell stack 27 in any manner, or may not be connected. Furthermore, each single cell 28 in the cell stack 27 may be connected in series with each other, or the cell stack 27 may have only one single cell 28. Further, in this embodiment, one annular bellows is provided, but two or more annular bellows may be provided. According to apparent this invention from the above description, even when the cylindrical cell Rusutakku is positioned vertically by the generator furnace casing, power reactor casings grayed cell stack Ri by the supporting support member secured to the inside
Fixed with both ends supported, and because it is so as to absorb the expansion and contraction means provided to differential thermal expansion that occurs between the cell stack and the power reactor casing to the generator furnace casing, without significant stress to the cell stack The cell stack can be supported in the power reactor casing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional front view of a solid oxide fuel cell type power reactor according to one embodiment of the present invention. FIG. 2 is a cross-sectional plan view showing details around a single cell. FIG. 3 is a sectional front view of a solid oxide fuel cell type power generating furnace according to another embodiment of the present invention. FIG. 4 is a sectional front view of a conventional solid oxide fuel cell power generator. FIG. 5 is a cross-sectional front view of another conventional solid oxide fuel cell power generator. [Description of Signs] 1 ... power generation furnace casing, 1a ... bottom plate (supporting member),
3 ... air gas partition plate (support member), 7 ... cell stack, 8 ... single cell, 8a ... solid electrolyte, 8b ... air electrode, 8c ... fuel electrode, 14 ... bellows (expansion and contraction means), 21 ... power generation furnace casing, Reference numeral 22 denotes a first air gas partition plate (support member), 23 denotes a second air gas partition plate (support member), 27 denotes a cell stack, 28 denotes a single cell, and 32 denotes a bellows (expansion and contraction means).

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takenori Nakajima 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (56) References JP-A-63-207055 (JP, A) JP-A-63- 110560 (JP, A) JP-A-3-1303065 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 8/12 H01M 8/02 H01M 8/24

Claims (1)

(57) Patent Claims 1. A solid electrolyte has a single cell formed by sandwiching a pair of electrodes, a cylindrical cell Rusutakku that Ru air and fuel gas is passed through the inside and outside In a solid oxide fuel cell type power reactor supported by the power generator casing while being positioned vertically in a power reactor casing forming an outer surface of the power reactor, both ends of the cell stack
Part is fixed to the support member fixed in the power generator casing
Is, and both the are supported, around the power reactor casing between the support member, together with the bellows to absorb the thermal expansion difference between this power reactor casing the cell stack is provided, wherein this bellows A solid oxide fuel cell type power reactor, wherein a power reactor casing is made of the same material.