JP2013171789A - Solid oxide fuel battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide fuel battery which, even when a deteriorated cell occurs, can continue to generate electricity without affecting the other cells.SOLUTION: A solid oxide fuel battery has a plurality of cell stacks 11 housed therein, in each of which cells 20, each including a fuel electrode, a solid electrolyte membrane and an air electrode 23 in a substrate tube, are formed in the circumferential direction of the substrate tube, and a plurality of the cells 20 are arranged along the longer direction of the substrate tube, and an interconnector electrically connecting the cells 20 together in series is formed between the adjacent cells 20. As opposite ends of the plurality of cell stacks 11 are coupled one to another by metal plate, the plurality of cell stacks 11 are electrically arranged in parallel, so that at an operation temperature, the air electrode 23 of any of the cells 20 of any of the cell stacks 11 contacts the air electrode 23 of the cell 20 of the cell stack 11 adjacent thereto to become electrically connected.

Description

  The present invention relates to a solid oxide fuel cell in which a plurality of cell stacks are housed.

  A cylindrical solid oxide fuel cell (SOFC) has a plurality of cells in which a fuel electrode, a solid electrolyte membrane, and an air electrode are stacked in the circumferential direction on a base tube, and adjacent cells are interconnectors. A cell stack electrically connected in series is provided. Both end portions of the plurality of cell stacks are arranged in parallel by being fitted into a tube plate having a plurality of holes, and are accommodated inside the solid oxide fuel cell. A current collecting plate is disposed at each end of the cell stack, and the plurality of cell stacks are electrically connected to each other in parallel by the current collecting plate (see Patent Document 1).

  In a cylindrical solid oxide fuel cell, an air electrode, a solid electrolyte, and a fuel electrode are formed on the surface of a cylindrical support tube. In the cylindrical solid oxide fuel cell disclosed in Patent Document 3, an air electrode is formed on the inner surface of the cylindrical solid electrolyte, and a fuel electrode is formed on the outer surface. In both Patent Document 2 and Patent Document 3, there is a region where the solid electrolyte and the fuel electrode do not exist in the longitudinal direction of the cylinder, and an interconnector electrically connected to the air electrode is exposed to the outside in that region. ing. That is, one cylinder constitutes one cell.

  In Patent Document 2, a plurality of the above cells are connected in the longitudinal direction of a cylinder, and an interconnector of one cell and a fuel electrode of an adjacent cell are connected in series. A plurality of fuel cells connected in series are arranged in parallel, and the fuel cells are connected in series by a conductive member.

  In Patent Document 3, a conductive plate mainly composed of Ni is disposed between an interconnector of one cell and a fuel electrode of an adjacent cell, and the cells are electrically connected in series.

JP 2007-109598 A (paragraph [0023], FIG. 1) Japanese Patent No. 3595091 (paragraphs [0012] to [0022], FIGS. 1 to 6) Japanese Patent No. 4663137 (Claim 1, paragraphs [0022] to [0027], [0033], FIGS. 1 and 2)

  The electric circuit diagram of the cell stack in the cylindrical solid oxide fuel cell is as shown in FIG. Since the cells 61 are connected in series, the currents flowing through the cells 61 in one cell stack 60 are the same. The solid oxide fuel cell is operated with the voltage at both ends being equipotential between the cell stacks 60.

  When a plurality of cell stacks are arranged as shown in the electric circuit diagram of FIG. 8, when a certain cell deteriorates, the resistance of the cell increases and the performance of the cell decreases. The current supplied to the cell stack including the deteriorated cell is smaller than the amount of current supplied to the other cell stack. That is, if there is even one deteriorated cell in the cell stack, it affects the entire cell stack and the amount of current to other healthy cells also decreases, so the power generation amount in that cell stack decreases. It was. In addition, the amount of current supplied to other cell stacks other than the cell stack including the deteriorated cells increases. Since the durability of the cell depends on the current density, there is a problem that the durability of other cell stacks may be lowered.

  In view of the above problems, an object of the present invention is to provide a solid oxide fuel cell capable of continuing power generation without affecting other cells even when a deteriorated cell is generated.

  In order to solve the above problems, the present invention provides a cell including a fuel electrode, a solid electrolyte membrane, and an air electrode formed on a base tube in a circumferential direction of the base tube, and a plurality of the cells are formed on the base tube. A solid oxide fuel cell in which a plurality of cell stacks arranged in the longitudinal direction and having interconnectors for electrically connecting the cells in series between adjacent cells are accommodated in a plurality of cells. In addition, by connecting both ends of the plurality of cell stacks with metal plates, the plurality of cell stacks are electrically arranged in parallel, and at any operating temperature, any of the cells in any of the cell stacks A solid oxide fuel cell is provided in which the air electrode is in contact with and electrically connected to the air electrode of the cell of the adjacent cell stack.

  In the above invention, it is preferable that the air electrodes of all the cells of all the cell stacks are in contact with the air electrodes of the cells in the adjacent cell stack.

  In the solid oxide fuel cell of the present invention, the current generated in any cell not only passes through the cells connected in series in the cell stack, but also passes through the cells in the adjacent cell stack via the air electrode. Collected. Therefore, when a cell in a certain cell stack deteriorates, a current generated in a cell in the same cell stack can flow to an adjacent cell stack via the air electrode of a cell other than the deteriorated cell. For this reason, even if a deteriorated cell occurs in the cell stack, another normal cell contributes to power generation. The solid oxide fuel cell of the present invention can maintain a high power generation amount even when a deteriorated cell is generated.

Alternatively, in the above invention, the air electrodes of some of the cells of some of the cell stacks are separated from the air electrodes of the cells of the adjacent cell stack, and the air electrodes of the remaining cells are It may be in contact with the air electrode of the cell of the adjacent cell stack.
In this case, when the air electrodes are in contact with each other, the air electrodes are formed thicker than when the air electrodes are separated from each other.

In the solid oxide fuel cell of the present invention, some cells are brought into contact with the cells of the adjacent cell stack to ensure electrical connection between the cell stacks. At the same time, some cells are separated from the cells in the adjacent cell stack. In this way, a desired oxidant gas flow path can be created in the power generation section of the cell stack.
In the present invention, by changing the film thickness of the air electrode, the cells can be brought into contact with or separated from each other at a predetermined position. That is, a desired oxidizing gas flow path can be appropriately set by an easy method.

  In this case, the air electrode is relatively thick and the air electrode is relatively positioned so that the oxidizing gas flows in a meandering manner around the cell stack to increase the flow path of the oxidizing gas. It is preferable that the thin cells are arranged.

  As described above, when the flow path of the oxidizing gas in the power generation section of the cell stack is lengthened, the pressure loss of the oxidizing gas inside the solid oxide fuel cell increases, and the flow rate of the oxidizing gas can be increased. Moreover, since the residence time of the oxidizing gas is increased around the power generation unit, the heat transfer characteristics can be improved.

  In the above invention, the air electrode may be in contact with the air electrode of the cell of the adjacent cell stack via a conductive film, and the conductive film may be formed on at least one of the air electrodes.

In this case, the conductive film includes LaCrO ₃ , (La, Sr) CrO ₃ , La (Cr, Mg) O ₃ , (La, Ca) CrO ₃ , (Sr, La) TiO ₃ , (La, Sr) MnO. ₃ , (La, Sr, Ca) MnO ₃ , (La, Sr) FeO ₃ , (La, Sr, Ca) FeO ₃ , (La, Sr) CoO ₃ , (La, Sr, Ca) CoO ₃ It is preferable that it is a film | membrane.

  By providing the conductive film, the conductivity between the cells when the cells contact each other can be improved.

In the solid oxide fuel cell of the present invention, not only cells are electrically connected within one cell stack, but also cells are electrically connected between adjacent cell stacks. When a deteriorated cell is generated in an arbitrary cell stack, a current generated in another normal cell in the cell stack flows to a cell in the adjacent cell stack through the air electrode. That is, even if a deteriorated cell occurs in the cell stack, another normal cell contributes to power generation. For this reason, a high power generation amount can be maintained.
Further, it is possible to prevent the current supply amount to other cell stacks from increasing and the durability of the other cell stacks from being lowered. As a result, high durability can be ensured for the entire solid oxide fuel cell.

1 is a schematic view of a solid oxide fuel cell according to a first embodiment. It is the schematic of the cell stack electric power generation vicinity of the solid oxide fuel cell which concerns on 1st Embodiment at the time of electric power generation. It is an electric circuit diagram of the cell stack in the solid oxide fuel cell according to the first embodiment. In the solid oxide fuel cell according to the first embodiment, it is an electric circuit diagram illustrating a current flow when a deteriorated cell is generated. It is the schematic of the cell stack electric power generation part vicinity of the solid oxide fuel cell which concerns on 2nd Embodiment at the time of electric power generation. It is the schematic of the cell stack electric power generation vicinity of the solid oxide fuel cell which concerns on another example of 2nd Embodiment at the time of electric power generation. It is the schematic of the cell stack electric power generation vicinity of the solid oxide fuel cell which concerns on another example of 2nd Embodiment at the time of electric power generation. It is an electric circuit diagram of the cell stack in the conventional solid oxide fuel cell.

<First Embodiment>
The solid oxide fuel cell according to the first embodiment will be described below.
1A and 1B are schematic views of a solid oxide fuel cell according to a first embodiment, in which FIG. 1A is a front longitudinal sectional view, FIG. 1B is a side longitudinal sectional view, and FIG. ) Is a top view.

  The solid oxide fuel cell 1 according to the first embodiment includes a container 2 and tube plates (metal plates) 3a and 3b. The tube plate 3 a partitions the inside of the container 2 into a power generation chamber 4 and a fuel supply chamber 5 provided on the power generation chamber 4. The tube sheet 3b partitions the inside of the container 2 into a power generation chamber 4 and a fuel discharge chamber 6 provided at the lower portion of the power generation chamber 4.

  An oxidizing gas supply unit 7 is connected to the lower part of the power generation chamber 4. An oxidizing gas discharge unit 8 is connected to the upper part of the power generation chamber 4. Depending on the size of the power generation chamber 4, a plurality of oxidizing gas supply units 7 and oxidizing gas discharge units 8 may be installed in the power generation chamber 4. In this embodiment, the oxidizing gas is a gas containing oxygen, and air is particularly preferable.

  A fuel supply unit 9 is connected to the fuel supply chamber 5. A fuel discharge unit 10 is connected to the fuel discharge chamber 6. In the present embodiment, the fuel gas is hydrogen gas or methane gas.

  The container 2 stores a plurality of cell stacks 11 therein. The cell stack 11 is composed of a porous substrate tube. A power generation unit is formed at the center of the cell stack 11, and both sides of the power generation unit are non-power generation units. The non-power generation portions of the plurality of cell stacks 11 are fixed by tube plates 3a and 3b, respectively. A plurality of holes are opened in the tube plates 3a, 3b, and the cell stacks 11 are fitted into the holes via seal rings (not shown). A plurality of cell stacks 11 are aligned by the tube sheet 3. In the example shown in FIG. 1, seven cell stacks 11 are aligned when viewed from the front, and 30 cell stacks 11 are aligned when viewed from the side. However, the number of cell stacks 11 accommodated is not limited to the above.

  A part of the power generation unit and the non-power generation unit of the cell stack 11 are housed in the power generation chamber 4, but both ends of the non-power generation unit are disposed in the fuel supply chamber 5. As a result, the fuel gas in the fuel supply chamber 5 flows inside the cell stack 11 and is discharged to the fuel discharge chamber 6.

In the power generation unit of the cell stack 11, a plurality of cells are formed along the longitudinal direction of the cell stack 11. For example, 85 cells are formed in one cell stack 11, but the present invention is not limited to this.
One cell is formed along the circumferential direction of the base tube. One cell is composed of a stack of a fuel electrode, a solid oxide film, and an air electrode from the base tube side. Adjacent cells are connected by an interconnector. Ca-stabilized zirconia is applied as the base tube material. As the fuel electrode material, for example, a mixture of Ni and YSZ is applied. YSZ is applied as the solid electrolyte membrane material. As the air electrode material, LaMnO ₃ -based material, LaFeO ₃ -based material, LaCoO ₃ -based material, or the like is applied. As the interconnector material, LaCrO ₃ , (La, Sr) CrO ₃ , La (Cr, Mg) O ₃ , (La, Ca) CrO ₃ , (Sr, La) TiO ₃ are applied.

  The heat insulating material 12 is installed around the non-power generation portion of the cell stack 11 inside the power generation chamber 4 and around the outside of the power generation chamber 4 corresponding to the position of the non-power generation portion of the cell stack 11. The cell stack 11 and the heat insulating material 12 are separated from each other, and the oxidizing gas can flow through the gap. At the time of power generation, the power generation unit is heated to 750 ° C. to 950 ° C., but the periphery of the tube plates 3a and 3b is set to about 550 ° C. according to the specifications from the material side. By providing the heat insulating material 12, the power generation unit is maintained at a high temperature. In addition, by providing the heat insulating material 12, the area of the flow path of the oxidizing gas is reduced, and the flow velocity of the oxidizing gas is increased.

  In the fuel supply chamber 5 and the fuel discharge chamber 6, current collector plates 13 a and 13 b are respectively installed at both ends of the cell stack 11. Current collector plates 13a and 13b are connected to collector electrodes 14a and 14b, respectively. The plurality of cell stacks 11 are electrically connected in parallel by the current collector plates 13a and 13b.

FIG. 2 is a schematic view of the vicinity of the power generation unit of the cell stack during power generation of the solid oxide fuel cell according to the first embodiment. 2A is a longitudinal sectional view, and FIG. 2B is a transverse sectional view of the power generation unit.
During power generation of the solid oxide fuel cell according to the first embodiment, the power generation unit 22 of the cell stack 11 is heated to about 750 ° C. to 950 ° C. In the power generation unit 22, the air electrodes 23 of all the cells 20 are in contact with the air electrodes 23 of the cells 20 of the adjacent cell stack 11. That is, the air electrodes of the cells 20 located at the same height of the adjacent cell stacks 11 are in contact with each other. In one cell stack, the air electrodes are not in contact with each other, and the solid electrolyte membrane and the interconnector are exposed between the air electrodes between adjacent cells (reference numeral 24 in FIG. 2). On the other hand, no cell is formed in the non-power generation unit 21.

  FIG. 3 is an electric circuit diagram of the solid oxide fuel cell according to the first embodiment. The cell 20 is represented by a resistor 25 and a battery 26. In one cell stack 11, cells 20 are connected in series. The cell stacks 11 are connected in parallel not only between the ends of the cell stacks 11 but also between the cells 20.

Fuel gas is supplied from the fuel supply unit 9 into the fuel supply chamber 5. The fuel gas flows from the fuel supply unit 9 to the inside of the base tube of the cell stack 11 and circulates inside the cell stack 11.
An oxidizing gas is supplied from the oxidizing gas supply unit 7 into the power generation chamber 4. The oxidizing gas passes between the cell stack 11 and the heat insulating material 12 and flows into the vicinity of the power generation unit 22 of the cell stack 11. The oxidizing gas that has flowed around the power generation unit 22 flows through the gap between the cylindrical cell stacks 11 in FIG. 2B or the gap between the cell stack 11 and the power generation chamber 4 in FIG.

  The fuel gas flowing inside the cell stack 11 diffuses outward from the base tube side. The oxidizing gas flowing outside the cell stack 11 diffuses from the air electrode 23 toward the base tube. In the solid electrolyte membrane, the fuel gas and oxygen in the oxidizing gas react to generate electricity. The generated current not only passes through the cells 20 connected in series in the cell stack 11 but also passes through the cells 20 in the adjacent cell stack 11 via the air electrode and reaches the current collector plate 13. The current is taken out through the collector electrode 14.

  The fuel gas that has not contributed to the reaction flows out from the cell stack 11 to the fuel discharge chamber 6. The fuel gas in the fuel discharge chamber 6 is discharged outside the solid oxide fuel cell 1 through the fuel discharge unit 10. The oxidizing gas that has not contributed to the reaction is discharged outside the solid oxide fuel cell 1 through the oxidizing gas discharge unit 8.

  FIG. 4 is an electric circuit diagram showing an example of a current flow when a deteriorated cell is generated. When any cell in any cell stack deteriorates, the resistance in the deteriorated cell 27 becomes larger than other normal cells. For this reason, the current generated in the other cells 20 flows so as to bypass the deteriorated cell 27 and reaches the current collector 13. Other normal cells 20 in the same cell stack 11 as the deteriorated cell 27 generate power. The generated current flows from any normal cell 20 in the cell stack 11 to the adjacent cell stack 11 via the air electrode. In this embodiment, even if the deteriorated cell 27 occurs, other normal cells 20 in the same cell stack 11 can contribute to power generation.

  In the solid oxide fuel cell 1 of the present embodiment, the cell stack 11 only needs to expand during power generation and the air electrodes 23 of the cell 20 are in contact with each other. Therefore, when the cell stack 11 is fitted to the tube plates 3a and 3b (room temperature ) Does not necessarily require that the air electrodes 23 of the cells 20 of the adjacent cell stacks 11 are in contact with each other. The thickness of the air electrode 23 is determined in consideration of the distance between the cell stacks, the cell temperature during power generation, the thermal expansion coefficient of each layer of the cell stack, and the like. For example, when the air electrodes 23 come into contact with each other due to thermal expansion, if there is a concern that the air electrode 23 may be damaged due to large stress, the cells 20 are separated from each other at room temperature, The thickness of the air electrode 23 is designed to ensure contact.

In order to improve conductivity when the air electrodes 23 of the cells 20 are in contact with each other, a conductive film may be formed on the surface of the air electrode 23 of each cell 20. The conductive film is formed on the air electrode 23 of at least one of the two cells 20 in contact. The conductive film is made of conductive ceramics. The conductive ceramic applicable to the present embodiment is required to have high conductivity and a thermal expansion coefficient comparable to that of the air electrode material (LaMnO ₃ -based material, LaFeO ₃ -based material, LaCoO ₃ -based material). Is done. Specifically, the conductive ceramic includes conductive materials represented by LaCrO ₃ , (La, Sr) CrO ₃ , La (Cr, Mg) O ₃ , (La, Ca) CrO ₃ , and (Sr, La) TiO _3. A functional oxide is applicable. These are materials used for interconnectors. Alternatively, the conductive film may be a LaMnO ₃ based material, a LaFeO ₃ based material, or a LaCoO ₃ based material. Specifically, (La, Sr) MnO ₃ , (La, Sr, Ca) MnO ₃ , (La, Sr) FeO ₃ , (La, Sr, Ca) FeO ₃ , (La, Sr) CoO ₃ , (La , Sr, Ca) CoO ₃ represented by a conductive oxide is applicable. In this case, the conductive film uses a material different from the air electrode.

  The conductive film may be formed on the entire surface of the air electrode 23, or may be formed on a part of the surface of the air electrode 23. The conductive film is formed using screen printing or a jet dispenser. After forming the conductive film, the cell stack 11 may be fired to sinter the conductive film. Alternatively, the cell stack 11 may be housed in the solid oxide fuel cell 1 without firing after forming the conductive film. In this case, the conductive film is sintered by heating the cell stack 11 during operation.

  The film thickness of the conductive film is determined in consideration of the distance between the cell stacks, the thickness of the air electrode, the temperature of the cell during power generation, the thermal expansion coefficient of each layer of the cell stack, and the like. When the conductive film is provided, the thickness of the air electrode is appropriately set in consideration of the thickness of the conductive film.

Second Embodiment
A solid oxide fuel cell according to the second embodiment will be described below. The solid oxide fuel cell of the second embodiment is the same as that of the first embodiment except for the power generation part of the cell.

FIG. 5 is a schematic view of the vicinity of the power generation unit of the cell stack during power generation, for the solid oxide fuel cell according to the second embodiment. FIG. 5A is a front longitudinal sectional view, and FIG. 5B is a longitudinal sectional view seen from the right side of FIG. 5A. FIG. 5 shows an example in which nine cell stacks 30 are arranged when viewed from the front and five cell stacks 30 are arranged when viewed from the side, and six cells 31 are formed in one cell stack 30.
In the solid oxide fuel cell according to the second embodiment, the air electrodes 32a of some of the cells 31 in some of the cell stacks 30 are not in contact with the air electrodes 32b of the cells 31 of the adjacent cell stacks 30 and are separated from each other. doing. The air electrode 32 b of the remaining cell 31 is in contact with the air electrode 32 b of the cell 31 of the adjacent cell stack 30. In the example of FIG. 5, the cell in which the air electrode 32a is separated from the air electrodes of other cells is provided at an arbitrary position. The cells 31 of the adjacent cell stacks 30 are electrically connected only at the portion where the air electrodes are in contact with each other.

  The air electrode 32b of the cell 31 that is in contact with the air electrode 32b of the cell 31 of the adjacent cell stack 30 is formed relatively thicker than the air electrode 32a of the cell 31 that is not in contact. Thus, in order to change the thickness of the air electrode of the cell 31 in one cell stack 30, it is good to form an air electrode using a jet dispenser.

  The oxidizing gas flowing into the periphery of the power generation section of the cell stack 30 flows through the gap between the cylindrical cell stacks 30 and also through the gap between the cells 31 where the air electrode is not in contact. If the flow area of the gap between the cells 31 that are not in contact with the air electrode is larger than the gap between the cell stacks 30, the oxidizing gas mainly flows between the cells 31.

  FIG. 6 is a schematic view of the vicinity of the power generation unit of the cell stack during power generation, for another example of the solid oxide fuel cell according to the second embodiment. 6 (a) is a front longitudinal sectional view, FIG. 6 (b) is a longitudinal sectional view seen from the left side of FIG. 6 (a), and FIG. 6 (c) is a right side of FIG. 6 (a). It is the longitudinal cross-sectional view seen from the surface. The solid oxide fuel cell of FIG. 6 has eight cell stacks 40 when viewed from the front and four cells stack when viewed from the side, and 12 cells 41 are formed in one cell stack.

In the example of FIG. 6, two rows of air electrodes 42 b that are in contact with the air electrodes of the cells 41 of the adjacent cell stack 40 are provided in the vertical direction. When viewed from the front (FIG. 6A), the left end or the right end of the row of air electrodes 42b is an air electrode 42a that does not contact the air electrode of the cell of the adjacent cell stack. In FIG. 6, two air electrodes 42a are provided in each row. In FIG. 6A as viewed from the front, the rows of air electrodes 42b are arranged so that the positions where the air electrodes 42a are provided are alternately arranged in the vertical direction.
Between the row | line | columns of the air electrode 42b, the row | line | column in which only the air electrode 42a which does not contact the air electrode of the cell of an adjacent cell stack is provided is arranged.

  In the solid oxide fuel cell of FIG. 6, the flow area is designed so that the oxidizing gas that flows into the periphery of the power generation section mainly passes through the gaps of the cells 41 that are not in contact with the air electrode 42a. For this reason, when viewed from the front (FIG. 6A), the oxidizing gas circulates from below to above while meandering the power generation section. By doing so, the flow path of the oxidizing gas that circulates through the power generation unit becomes long, so that the pressure loss increases and the flow rate of the oxidizing gas around the power generation unit increases. Furthermore, since the residence time of the oxidizing gas in the power generation unit becomes longer, the heat exchange rate increases. Therefore, heat transfer characteristics are improved.

  In the example of FIG. 6, the number of rows in which the air electrodes 42b are provided in the vertical direction, the number of air electrodes 42a in the row, and the number of rows in which only the air electrodes 42a are provided are not particularly limited. These may be appropriately set in consideration of the flow area of the oxidizing gas. However, if the number of columns in which the air electrodes 42b are provided in the vertical direction increases, the cell 41 at the center of the column may not be sufficiently supplied with the oxidizing gas, so the number of columns is one or two. Is more advantageous.

  FIG. 7 is a schematic view of the vicinity of the power generation unit of the cell stack during power generation, for still another example of the solid oxide fuel cell according to the second embodiment. 7 (a) is a front longitudinal sectional view, FIG. 7 (b) is a longitudinal sectional view seen from the left side of FIG. 7 (a), and FIG. 7 (c) is a right side view of FIG. 7 (a). It is the longitudinal cross-sectional view seen from the surface. The solid oxide fuel cell shown in FIG. 7 has eight cell stacks 50 when viewed from the front and five cell stacks when viewed from the side, and 12 cells 51 are formed in one cell stack.

In the example of FIG. 7, two rows of air electrodes 52b that are in contact with the air electrodes of the cells 51 of the adjacent cell stack 50 are provided in the vertical direction. When viewed from the front (FIG. 7A), the row of air electrodes 52 b is provided across all the cell stacks 50. On the other hand, when viewed from the side (FIG. 7B, FIG. 7C), the left end or right end of the row of air electrodes 52b is not in contact with the air electrode 52a that is not in contact with the air electrode of a cell in the adjacent cell stack. It has become. In FIG. 7, one air electrode 52a is provided in each row. The rows of the air electrodes 52b are arranged so that the positions at which the air electrodes 52a are provided alternate in the vertical direction when viewed from the side.
Between the rows of the air electrodes 52b, rows in which only the air electrodes 52a are provided are arranged.

  Also in this example, the flow area is designed so that the oxidizing gas flowing into the periphery of the power generation section mainly passes through the gaps of the cells 51 that are not in contact with the air electrode 52a. For this reason, when viewed from the side (FIGS. 7B and 7C), the oxidizing gas circulates from below to above while meandering the power generation section. By doing so, the flow path of the oxidizing gas that circulates through the power generation unit becomes long, so that the pressure loss increases and the flow rate of the oxidizing gas around the power generation unit increases. Furthermore, since the residence time of the oxidizing gas in the power generation unit becomes longer, the heat exchange rate increases. Therefore, heat transfer characteristics are improved.

  In the example of FIG. 7, the number of rows in which the air electrodes 52b are provided in the vertical direction, the number of air electrodes 52a in the row, and the number of rows in which only the air electrodes 52a are provided are not particularly limited. It is preferable to set appropriately considering the flow path area.

Also in the second embodiment, a conductive film may be formed on the surface of the air electrode in a cell in which the air electrodes are in contact with each other.
In the case of providing a conductive film, the thickness of the air electrode may be the same in the cell stack, and contact between cells of the adjacent cell stack may be ensured by the conductive film. In this case, the conductive film is formed with a thickness that allows the cells to contact each other by thermal expansion during power generation.

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell 2 Container 3a, 3b Tube plate 4 Power generation chamber 5 Fuel supply chamber 6 Fuel discharge chamber 7 Oxidation gas supply part 8 Oxidation gas discharge part 9 Fuel supply part 10 Fuel discharge part 11, 30, 40, 50 , 60 Cell stack 12 Heat insulation material 13 Current collector plate 14 Current collector electrode 20, 31, 41, 51, 61 Cell 21 Non-power generation unit 22 Power generation unit 23, 32a, 32b, 42a, 42b, 52a, 52b Air electrode 24 Solid electrolyte membrane And interconnector 25, 65 resistance 26, 66 battery 27 deteriorated cell

Claims (7)

A cell including a fuel electrode, a solid electrolyte membrane, and an air electrode is formed on the base tube in the circumferential direction of the base tube, and a plurality of the cells are arranged along the longitudinal direction of the base tube, and the adjacent cells A solid oxide fuel cell containing a plurality of cell stacks in which an interconnector that electrically connects the cells in series is formed between
By connecting both ends of the plurality of cell stacks with a metal plate, the plurality of cell stacks are electrically arranged in parallel,
A solid oxide fuel cell in which the cathode of any of the cells in any of the cell stacks is in contact with and electrically connected to the cathode of the cells of the adjacent cell stack at an operating temperature.   2. The solid oxide fuel cell according to claim 1, wherein the cathodes of all the cells of all the cell stacks are in contact with the cathodes of the cells in the adjacent cell stack.   The cathodes of some of the cells of some of the cell stacks are spaced apart from the cathodes of the cells of the adjacent cell stack, and the cathodes of the remaining cells of the adjacent cell stack The solid oxide fuel cell according to claim 1, which is in contact with the air electrode of the cell.   The solid oxide fuel cell according to claim 3, wherein when the air electrodes are in contact with each other, the air electrode is formed thicker than when the air electrodes are separated from each other.   The cell having a relatively thick air electrode and the cell having a relatively thin air electrode so that the circulation path of the oxidant gas becomes longer due to the meandering gas flowing through the periphery of the cell stack. The solid oxide fuel cell according to claim 3 or 4, wherein The air electrode is in contact with the air electrode of the cell of the adjacent cell stack through a conductive film;
The solid oxide fuel cell according to any one of claims 1 to 5, wherein the conductive film is formed on at least one of the air electrodes. The conductive film is composed of LaCrO ₃ , (La, Sr) CrO ₃ , La (Cr, Mg) O ₃ , (La, Ca) CrO ₃ , (Sr, La) TiO ₃ , (La, Sr) MnO ₃ , ( La, Sr, Ca) MnO ₃ , (La, Sr) FeO ₃ , (La, Sr, Ca) FeO ₃ , (La, Sr) CoO ₃ , (La, Sr, Ca) CoO ₃ The solid oxide fuel cell according to claim 6.

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