JP5554090B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell having a cylindrical shape.

  A solid oxide fuel cell (SOFC) is a fuel cell that generates electric power by an electrochemical reaction between a fuel gas reformed by reacting a hydrocarbon or oxygen-containing hydrocarbon with water vapor and oxygen. During this power generation, water is generated. When a reverse reaction is performed by a fuel cell, hydrogen and oxygen are generated from water. The fuel cell used in this way is called a water electrolysis device or a water electrolysis cell.

  In this solid oxide fuel cell, a power generation element is formed by laminating a fuel electrode, a solid oxide electrolyte, and an air electrode on the outer peripheral surface of a cylindrical base tube. A plurality of power generation elements are arranged in series in a predetermined interval (gap), and a plurality of power generation elements are connected in series by an interconnector.

  Accordingly, when the fuel gas is supplied into the base tube and oxygen is supplied to the air electrode, the oxygen supplied to the air electrode is ionized, permeates the electrolyte membrane, and reaches the fuel electrode. A potential difference is generated between the fuel electrode and the air electrode due to an electrochemical reaction between oxygen and fuel gas that has reached the fuel electrode, and electricity is generated by taking out the generated potential difference to the outside.

  An example of such a fuel cell is described in Patent Document 1 below. The fuel cell described in Patent Document 1 includes a power generation element in which a fuel electrode, a solid electrolyte, and an air electrode are sequentially stacked on the surface of a columnar support body in which a fuel gas passage is formed in the axial length direction. A plurality of power generation elements are provided in series in the longitudinal direction, and a plurality of power generation elements are connected in series with an interconnector, and the support is made of an iron group metal and / or an iron group metal oxide, inorganic powder, A porous insulating layer that electrically insulates the support base from the power generating element is provided on the surface of the porous support base that contains the main component.

JP 2004-179071 A

  By the way, this solid oxide fuel cell is manufactured by applying the fuel electrode, the electrolyte, the interconnector, and the air electrode on the outer surface of the base tube, and firing them. In this case, since the interconnector and the electrolyte have different compositions, their thermal expansion coefficients are different, and a minute gap is generated at the interface between the two after firing. Therefore, when the supply amount of fuel gas decreases in the base tube during abnormal operation of the fuel cell, when the differential pressure reversal phenomenon occurs in which the pressure on the fuel electrode side decreases with respect to the air electrode, oxygen is interconnected from the air electrode side. And leak through the minute gap between the electrolyte and the fuel electrode. Then, the leaked oxygen reacts with nickel contained in the fuel electrode and the base tube to generate nickel oxide, and the fuel electrode and the base tube expand (reoxidation expansion), so that the base tube may be damaged. There is sex. That is, when the outer peripheral portion of the fuel electrode and the base tube expands, compressive stress is generated here, while tensile stress acts on the inner peripheral portion of the base tube, and as a result, the base tube is damaged by the internal stress.

  The present invention solves the above-described problems, and an object of the present invention is to provide a fuel cell that improves durability and reliability by preventing damage to a base tube by improving robustness.

In order to achieve the above object, a fuel cell of the present invention includes a fuel cell, a solid electrolyte, and an air electrode that are sequentially laminated on the outer surface of a cylindrical substrate tube, and the power generation device is formed on the substrate. In the fuel cell in which a plurality of power generation elements are arranged in the axial direction of the tube and the plurality of power generation elements are connected in series by an interconnector, on the outer surface of the base tube, at the boundary between the interconnector and the solid electrolyte A plurality of gas-impermeable layers are arranged at predetermined intervals in the axial direction of the base tube, and the power generation includes the solid electrolyte that forms the boundary portion facing the gas-impermeable layer outside the gas-impermeable layer. element (hereinafter, referred to as the counter power device) with the fuel electrode of the is provided, adjacent to the gas impermeable layer, provided the solid electrolyte of the power generating element next to the counter generating element, a fuel electrode of the counter generating elements Outside By solid electrolyte the counter generating elements are provided, the gas impermeable layer adjacent, together are separated by a solid electrolyte, also fuel poles to form a power generating element adjacent each separated by a solid electrolyte, it and characterized To do.

  In the fuel cell of the present invention, the gas impermeable layer is formed as a coating film having a predetermined thickness on the outer surface of the base tube.

In the fuel cell of the present invention, the gas-impermeable layer is formed in an inter-element region in which at least one of the fuel electrode, the solid electrolyte, and the air electrode is not stacked in a region in an axial direction of the base tube. It is characterized by being provided.

In the fuel cell of the present invention, the gas impermeable layer is formed of a non-porous material.

According to the fuel cell of the present invention, the fuel electrode, the solid electrolyte, and the air electrode are sequentially laminated on the outer surface of the cylindrical base tube to form a power generation element, and the power generation element is predetermined in the axial direction of the base tube. A plurality of power generation elements are arranged in series with an interconnector at intervals, and a gas-impermeable layer is formed on the outer surface of the substrate tube at the boundary between the interconnector and the solid electrolyte. A fuel electrode of a power generating element (hereinafter referred to as a counter power generating element) having a solid electrolyte that is arranged in a plurality of positions with a predetermined interval in the axial direction of the gas and has a boundary portion facing the gas impermeable layer outside the gas impermeable layer together are provided, adjacent to the gas impermeable layer, it provided the solid electrolyte of the power generating element next to the opposite power generation elements, the solid electrolyte of the counter generating element is provided outside the fuel electrode of the counter generating element Because of the adjacent gas Kaso, together separated by a solid electrolyte, also fuel poles to form a power generating element adjacent respectively as separated by a solid electrolyte. Therefore, by providing a gas impervious layer corresponding to the boundary between the interconnector and the solid electrolyte between the base tube and the fuel electrode, it is possible to suppress air leakage from the air electrode side to the base tube side and to be robust. As a result, it is possible to prevent damage to the base tube and improve durability and reliability.

  According to the fuel cell of the present invention, since the gas impermeable layer is formed as a coating film having a predetermined thickness on the outer surface of the base tube, the same method as the fuel electrode, solid electrolyte, air electrode, etc. The manufacturing process can be prevented from becoming complicated.

According to the fuel cell of the present invention, the gas-impermeable layer is provided in the inter-element region in which at least one of the fuel electrode, the solid electrolyte, and the air electrode is not stacked in the axial direction of the base tube. A decrease in power generation efficiency due to the impermeable layer and the reinforcing portion can be suppressed.

According to the fuel cell of the present invention, since the gas-impermeable layer is formed of a non-porous material, the composition of the gas-impermeable layer and the reinforcing portion can be simplified, and the manufacturing cost can be reduced.

FIG. 1 is a schematic configuration diagram illustrating a fuel cell according to Embodiment 1 of the present invention. FIG. 2 is a schematic configuration diagram showing a fuel cell according to Embodiment 2 of the present invention. FIG. 3 is a schematic configuration diagram showing a fuel cell according to Embodiment 3 of the present invention.

  Exemplary embodiments of a fuel cell according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example.

  FIG. 1 is a schematic configuration diagram illustrating a fuel cell according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the fuel cell of Example 1 is configured such that a fuel electrode 12, a solid electrolyte 13, and an air electrode 14 are sequentially laminated on the outer surface of a cylindrical base tube 11 and a power generation element 15 is formed. A plurality of power generation elements 15 are formed at predetermined intervals in the axial direction of the base tube 11, and a plurality of power generation elements 15 are connected in series by an interconnector 16. The gas is intermittently impermeable between the base tube 11 and the fuel electrode 12 in the axial direction of the base tube 11 corresponding to the power generating elements 15 arranged in the axial direction of the base tube 11. A layer 17 is provided. In this embodiment, the gas impermeable layer 17 is provided between the outer surface of the base tube 11 and the fuel electrode 12 and corresponding to the boundary between the interconnector 16 and the solid electrolyte 13.

The fuel cell of Example 1 will be specifically described. The base tube 11 is a ceramic cylinder and contains an iron group metal (for example, Ni), an iron group metal oxide (for example, NiO) having an internal reforming ability, an alloy or an alloy oxide thereof. Yes, for example, a mixture of Ni and CSZ (calcia stabilized zirconia-CaO stabilized ZrO ₂ ). In this case, since the base tube 11 needs to pass the fuel gas in the fuel passage to the fuel electrode 12, it is porous, and it is necessary to adjust the particle diameter of the mixture or to mix the pore material. .

The fuel electrode 12 is, for example, a mixture of Ni and YSZ (yttrium stabilized zirconia-Y ₂ O ₃ stabilized ZrO ₂ ) and is porous. The solid electrolyte 13 is, for example, YSZ (yttrium-stabilized zirconia-Y ₂ O ₃ stabilized ZrO ₂ ), and is nonporous in order to avoid contact between the fuel electrode gas and the air electrode gas. The air electrode 14 is made of, for example, at least one kind of porous conductive ceramics such as a LaMnO ₃ -based material, a LaFeO ₃ -based material, and a LaCoO ₃ -based material.

In order to constitute the power generation element 15, the fuel electrode 12 and the air electrode 14 adjacent to the outside of the fuel electrode 12 are connected by the interconnector 16, and the fuel electrode 12 not covered by the interconnector 16 is solid. The solid electrolyte 13 is covered with the electrolyte 13 and is also present in the gap between the adjacent fuel electrodes 12. The interconnector 16 is made of, for example, a perovskite oxide such as SrTiO ₃ , a LaCrO ₃ -based material, or the like, and is made nonporous to prevent gas leakage.

The gas-impermeable layer 17 is a region where the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 are not laminated in the axial direction of the base tube 11, that is, the fuel electrode 12, the solid electrolyte 13, and the air electrode. 14 is provided in the inter-element region W ₀ where at least one of them is not laminated, and the gas impermeable layer 17 is formed on the outer surface of the base tube 11 as a coating film having a predetermined thickness. .

  The gas impermeable layer 17 preferably has at least the same thermal expansion coefficient as that of the fuel electrode 12, and more preferably has the same thermal expansion coefficient as that of the fuel electrode 12, the solid electrolyte 13, and the air electrode 14. The gas impermeable layer 17 is configured as a dense layer having a lower porosity than the base tube 11.

Specifically, in the fuel cell of the present embodiment, the surface side of the substrate tube 11, the area where all of the fuel electrode 12 and the solid electrolyte 13 and the air electrode 14 is not layered is the inter-element region W _0. That is, the surface side of the substrate tube 11, an element region between W ₀ is a region which is not stacked in one of the fuel electrode 12 and the solid electrolyte 13 and the air electrode 14. On the other hand, a region where all of the fuel electrode 12 and the solid electrolyte 13 and the cathode 14 are stacked is the power generation area W _1. The gas impermeable layer 17 is provided in the inter-element region W ₀ so as to cover the surface of the base tube 11.

The interconnector 16 is laminated on the outside of the solid electrolyte 13, the inside is disposed between the solid electrolytes 13 adjacent in the axial direction of the base tube 11, and is laminated on the outside of the fuel electrode 12. Therefore, this interconnector 16 is formed with boundary surfaces (boundary portions) B between the solid electrolytes 13, and the gas-impermeable layer 17 is provided in the inter-element region W ₀ corresponding to the boundary surfaces B. ing.

Further, the gas impermeable layer 17 is required to prevent the gas (mainly oxygen) from the power generation element 15 side from passing through the base tube 11 to the base tube 11 between the base tube 11 and the power generation element 15. Quality. Since the gas impermeable layer 17 is not provided in the power generation region W _1, hardly gives an adverse effect on the passing through the fuel gas in the substrate tube 11 to the fuel electrode 12.

In this case, the gas-impermeable layer 17 is made of, for example, La ₂ ZrO ₇ (lanthanum zirconate), Y ₃ Al ₅ O ₁₂ (yttrium aluminate), SrTi _{1 + x} O ₃ (strontium titanate), Al ₂ O ₃ (alumina). And a mixture of MgAl ₂ O ₄ (magnesium aluminate) and nonporous. In this case, since it is not porous, there is no need to adjust the particle diameter or mix the pore material, and as a result, the gas impermeable layer 17 has a lower porosity than the base tube 11.

  Further, since the fuel cell of this embodiment is formed by laminating the fuel electrode 12, the gas impermeable layer 17, the solid electrolyte 13, and the interconnector 16 on the outer surface of the base tube 11, this sintering is performed. It is necessary to be careful of cracks in time. For this reason, the gas impermeable layer 17 is mixed with materials such that the thermal expansion coefficient is the same as that of the base tube 11, the fuel electrode 12, the solid electrolyte 13, and the interconnector 16.

In the fuel cell according to Example 1 configured as described above, the base tube 11 is formed by extrusion molding on the outer peripheral surface of a cylindrical mandrel (not shown), and the gas impermeability is formed outside the base tube 11. After the layer 17, the fuel electrode 12, the solid electrolyte 13, and the interconnector 16 are stacked, the air electrode 14 is formed and sintered (for example, held at 1100 ° C. to 1300 ° C. for 1 hour). In this case, the gas-impermeable layer 17, the fuel electrode 12, the solid electrolyte 13, the interconnector 16, and the air electrode 14 form a uniformly mixed slurry by mixing the above-mentioned powder material with an organic solvent. A predetermined material is applied to a predetermined position on the outer surface of the base tube 11 by a printing method. The thickness of the fuel electrode 12 is about 30% of the thickness of the base tube 11, and the thickness of the gas impermeable layer 17 is several tens of μm and should be 10% or less of the thickness of the fuel electrode 12. It is desirable to set it to 5% or less. On the other hand, the axial length of the gas impermeable layer 17 is the minimum length only at a position corresponding to the boundary surface B between the solid electrolyte 13 and the interconnector 16, and an element including a position corresponding to this boundary surface B during regions W ₀ everything is maximum length, in which may be in the length range. In production, the gas-impermeable layer 17 does not extend from the inter-element region W ₀ to the power generation region W ₁ by a small amount.

  The fuel cell of the above-described embodiment reacts by the following operation. That is, the fuel gas serving as the fuel for the cell reaction flows inside the base tube 11, passes through the pores of the base tube 11, and reaches the fuel electrode 12. This fuel gas is steam reformed by the active metal contained in the fuel electrode 12. Hydrogen generated by steam reforming passes through the pores of the fuel electrode 12 and reaches the solid electrolyte 13. On the other hand, the air flows outside the base tube 11 (air electrode 14). The oxygen in the air is ionized while passing through the pores of the air electrode 14 or reaches the solid electrolyte 13. The ionized oxygen passes through the solid electrolyte 13 and reaches the fuel electrode 12. The oxygen ions that have passed through the solid electrolyte 13 react with the fuel gas. The potential difference generated by such a cell reaction is extracted from the fuel electrode 12 and the air electrode 14 to be generated.

  When an abnormality occurs during power generation by the fuel cell, for example, when the amount of fuel gas supplied into the base tube 11 is reduced, a differential pressure reversal phenomenon occurs in which the pressure on the fuel electrode 12 side decreases with respect to the air electrode 14 side. Occur. At this time, oxygen on the air electrode 14 side leaks to the fuel electrode 12 through a minute gap between the solid electrolyte 13 and the interconnector 16. However, in this embodiment, the gas impermeable layer 17 is provided between the base tube 11 and the fuel electrode 12 corresponding to the boundary surface B between the solid electrolyte 13 and the interconnector 16. Therefore, the leaked oxygen is not blocked by the gas impervious layer 17 and leaks from the fuel electrode 12 to the base tube 11 side, and reoxidation expansion of the base tube 11 is suppressed, and due to internal stress of the base tube 11. Damage is prevented.

  In this case, since the gas impermeable layer 17 is non-porous (dense layer), the strength of the base tube 11 itself is increased. Therefore, although oxygen on the air electrode 14 side reaches the solid electrolyte 13, the interconnector 16, and the fuel electrode 12 and is oxidized, the base tube 11 sufficiently receives the stress acting from the reoxidized and expanded fuel electrode 12. In this respect, the base tube 11 is prevented from being damaged.

  As described above, in the fuel cell of Example 1, the power generation element 15 is formed by sequentially laminating the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 on the outer surface of the cylindrical base tube 11. A plurality of elements 15 are arranged at predetermined intervals in the axial direction of the base tube 11, and a plurality of power generating elements 15 are connected in series by an interconnector 16, and are formed between the base tube 11 and the fuel electrode 12. Thus, a gas impermeable layer 17 is provided corresponding to the boundary surface B between the interconnector 16 and the solid electrolyte 13.

  Therefore, by providing the gas impermeable layer 17 corresponding to the boundary surface B between the interconnector 16 and the solid electrolyte 13 between the base tube 11 and the fuel electrode 12, the air electrode 14 side to the base tube 11 side is provided. Air leakage is suppressed, and it is possible to cope with an emergency operation, thereby improving the robustness. As a result, the base tube 11 can be prevented from being damaged and the durability and reliability can be improved.

  In the fuel cell of Example 1, the gas impermeable layer 17 is formed on the outer surface of the base tube 11 as a coating film having a predetermined thickness. Therefore, the gas-impermeable layer 17 can be formed by the same method as the fuel electrode 12, the solid electrolyte 13, the air electrode 14 and the like, and the manufacturing process can be prevented from becoming complicated.

  In the fuel cell of Example 1, the gas impermeable layer 17 is set to have the same thermal expansion coefficient as that of at least the fuel electrode 12 and the solid electrolyte 13. Therefore, the gas-impermeable layer 17, the fuel electrode 12, and the solid electrolyte 13 are in close contact with each other without any gap, and the generation of cracks during firing can be suppressed.

Further, in the fuel cell of Example 1, the gas impermeable layer 17 is disposed in the axial direction of the base tube 11 in the inter-element region W ₀ where at least one of the fuel electrode 12 and the solid electrolyte 13 is not laminated. Provided. Accordingly, a decrease in power generation efficiency due to the gas impermeable layer 17 can be suppressed.

  Further, in the fuel cell of Example 1, the gas impermeable layer 17 is formed of a nonporous material. Therefore, when the gas impermeable layer 17 is manufactured, it is not necessary to adjust the particle diameter or to mix the pore material, the composition of the gas impermeable layer 17 can be simplified, and the manufacturing cost can be reduced.

  FIG. 2 is a schematic configuration diagram showing a fuel cell according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 2, the fuel cell of Example 2 has a fuel electrode 12, a solid electrolyte 13, and an air electrode 14 sequentially stacked on the outer surface of a cylindrical base tube 11 so that a power generation element 15 is formed. A plurality of power generation elements 15 are formed at predetermined intervals in the axial direction of the base tube 11, and a plurality of power generation elements 15 are connected in series by an interconnector 16. Reinforcing portions 21 are provided intermittently in the axial direction of the base tube 11 on the inner surface of the base tube 11 and between the power generating elements 15 arranged in the axial direction of the base tube 11. In the present embodiment, a reinforcing portion 21 having a higher strength than the base tube 11 is provided on the inner surface of the base tube 11 and corresponding to the boundary portion between the interconnector 16 and the solid electrolyte 13.

  The fuel cell of Example 2 is substantially the same as the fuel cell of Example 1 described above, the configuration of the power generation element 15, and the point where the power generation element 15 is connected in series by the interconnector 16. Detailed description of the points will be omitted.

The reinforcing portion 21 is a region where the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 are not laminated in the axial direction of the base tube 11, that is, the fuel electrode 12, the solid electrolyte 13, and the air electrode 14. At least one of them is provided in the inter-element region W ₀ , and the reinforcing portion 21 is formed on the inner surface of the base tube 11 as a coating film having a predetermined thickness. In this case, the reinforcing portion 21 is provided on the inner surface side of the base tube 11, and the inner surface is provided uniformly with the inner surface of the base tube 11. That is, the reinforcing portion 21 is disposed so as to be embedded inside the base tube 11 on the inner surface side.

  The reinforcing portion 21 preferably has at least the same thermal expansion coefficient as that of the base tube 11, and more preferably has the same thermal expansion coefficient as that of the fuel electrode 12, the solid electrolyte 13, and the air electrode 14. The reinforcing portion 21 is configured as a dense layer having a lower porosity than the base tube 11.

Specifically, in the fuel cell of the present embodiment, the surface side of the substrate tube 11, the area not laminated in one of the fuel electrode 12 and the solid electrolyte 13 and the air electrode 14 is in inter-element region W ₀ . On the other hand, a region where all of the fuel electrode 12 and the solid electrolyte 13 and the cathode 14 are stacked is the power generation area W _1. The reinforcing portion 21 is provided in the inter-element region W ₀ so as to cover the inner surface of the base tube 11.

The interconnector 16 is laminated on the outside of the solid electrolyte 13, the inside is disposed between the solid electrolytes 13 adjacent in the axial direction of the base tube 11, and is laminated on the outside of the fuel electrode 12. Therefore, this interconnector 16 is formed with boundary surfaces (boundary portions) B between the solid electrolytes 13, and reinforcing portions 21 are provided in the inter-element regions W ₀ corresponding to the boundary surfaces B. .

The reinforcing portion 21 needs to have a strength higher than the strength of the base tube 11 on the inner surface side of the base tube 11. Further, it is effective that the reinforcing portion 21 does not transmit gas (mainly oxygen) from the power generation element 15 side to the base tube 11 side on the inner surface side of the base tube 11 and is desirably nonporous. . Since the gas impermeable layer 17 is not provided in the power generation region W _1, hardly gives an adverse effect on the passing through the fuel gas in the substrate tube 11 to the fuel electrode 12.

In this case, the reinforcing portion 21 includes La ₂ ZrO ₇ (lanthanum zirconate), Y ₃ Al ₅ O ₁₂ (yttrium aluminate), SrTi _{1 + x} O ₃ (strontium titanate), Al ₂ O ₃ (alumina) and MgAl ₂ O. ₄ (Magnesium aluminate) mixture is used. In this case, the reinforcing part 21 may be porous or non-porous.

  Further, in the fuel cell of this embodiment, the fuel electrode 12, the solid electrolyte 13, and the interconnector 16 are laminated on the outer surface of the base tube 11, and the reinforcing portion 21 is laminated on the inner surface and sintered (fired). It is necessary to pay attention to cracks during this sintering. Therefore, the material of the reinforcing portion 21 is set so that the thermal expansion coefficient is the same as that of the base tube 11, the fuel electrode 12, the solid electrolyte 13, and the interconnector 16.

In the fuel cell according to Example 2 configured as described above, the reinforcing portion 21 and the base tube 11 are formed by multiple (double) extrusion molding on the outer peripheral surface of a cylindrical mandrel (not shown). The fuel electrode 12, the solid electrolyte 13, the interconnector 16, and the air electrode 14 are laminated on the outside of the tube 11 and then manufactured by sintering (for example, holding at 1350 ° C. to 1400 ° C. for 1 hour). In this case, the fuel electrode 12, the solid electrolyte 13, the interconnector 16, and the air electrode 14 form a slurry in which the above-described powder material is mixed with an organic solvent to form a uniform mixture, and the substrate tube 11 is formed by screen printing. A predetermined material is applied to a predetermined position on the outer surface of the substrate. In this case, the axial length of the reinforcing portion 21 is the minimum length only at a position corresponding to the boundary surface B between the solid electrolyte 13 and the interconnector 16, and between the elements including the position corresponding to the boundary surface B. All the areas W ₀ have the maximum length, and only need to be within this length range. In production, the reinforcing portion 21 does not extend from the inter-element region W ₀ to the power generation region W ₁ by a small amount.

  When an abnormality occurs during power generation by the fuel cell of this embodiment, for example, when the amount of fuel gas supplied into the base tube 11 is reduced, the pressure on the fuel electrode 12 side is reduced with respect to the air electrode 14 side. Differential pressure reversal phenomenon occurs. At this time, oxygen on the air electrode 14 side leaks to the fuel electrode 12 through a minute gap between the solid electrolyte 13 and the interconnector 16. Therefore, oxygen on the air electrode 14 side reaches the solid electrolyte 13, the interconnector 16, and the fuel electrode 12, and these are oxidized. However, since the reinforcing portion 21 is strong, the strength of the base tube 11 itself is increased. Therefore, the base tube 11 can sufficiently receive the stress acting from the reoxidized and expanded fuel electrode 12, and the base tube 11 is prevented from being damaged.

  Thus, in the fuel cell of Example 2, the power generation element 15 is formed by sequentially laminating the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 on the outer surface of the cylindrical base tube 11, and this power generation A plurality of elements 15 are arranged at predetermined intervals in the axial direction of the base tube 11, and a plurality of power generating elements 15 are connected in series by an interconnector 16. A reinforcing portion 21 having a higher strength than the base tube 11 is provided corresponding to the boundary surface B between the solid electrolyte 13 and the solid electrolyte 13.

  Therefore, by providing the reinforcing portion 21 having higher strength than the base tube 11 corresponding to the boundary surface B between the interconnector 16 and the solid electrolyte 13 on the inner surface of the base tube 11, the rigidity of the base tube 11 itself is increased. Correspondence at the time of driving | operation becomes possible and robustness can be improved, As a result, damage to the base tube 11 can be prevented and durability and reliability can be improved.

Further, in the fuel cell of Example 2, the reinforcing portion 21 is provided in the inter-element region W ₀ where at least one of the fuel electrode 12 and the solid electrolyte 13 is not laminated in the axial direction of the base tube 11. ing. Therefore, a decrease in power generation efficiency due to the reinforcing portion 21 can be suppressed.

  Further, in the fuel cell of Example 2, the reinforcing portion 21 is formed of a nonporous material. Therefore, when manufacturing the reinforcement part 21, it is not necessary to adjust a particle diameter or to mix a pore material, the mixing | blending of the reinforcement part 21 can be simplified, and manufacturing cost can be reduced.

  Further, in the fuel cell of Example 2, the reinforcing portion 21 is provided on the inner surface side of the base tube 11, and the inner surface is provided uniformly with the inner surface of the base tube 11. Therefore, by making the inner peripheral surface of the base tube 11 a smooth surface without irregularities, the rigidity of the base tube 11 can be improved while minimizing the influence on the gas fluidity of the fuel gas and the gas permeability of the base tube 11. In addition, the manufacturing process can be prevented from becoming complicated.

  FIG. 3 is a schematic configuration diagram showing a fuel cell according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel cell of Example 3, as shown in FIG. 3, the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 are sequentially laminated on the outer surface of the cylindrical tube 11 so that the power generation element 15 is formed. A plurality of power generation elements 15 are formed at predetermined intervals in the axial direction of the base tube 11, and a plurality of power generation elements 15 are connected in series by an interconnector 16. Reinforcing portions 22 are provided intermittently in the axial direction of the base tube 11 on the inner surface of the base tube 11 and between the power generating elements 15 arranged in the axial direction of the base tube 11. In the present embodiment, a reinforcing portion 22 having a higher strength than the base tube 11 is provided on the inner surface of the base tube 11 and corresponding to the boundary between the interconnector 16 and the solid electrolyte 13.

  The fuel cell of Example 3 is substantially the same as the fuel cell of Examples 1 and 2 described above, the configuration of the power generation element 15, and the point where the power generation element 15 is connected in series by the interconnector 16. Detailed description of this point will be omitted.

In the region of the base tube 11 in the axial direction, the reinforcing portion 22 is not formed by stacking all of the fuel electrode 12, the solid electrolyte 13, and the air electrode 14, that is, the fuel electrode 12, the solid electrolyte 13, and the air electrode 14. At least one of them is provided in the inter-element region W ₀ , and the reinforcing portion 22 is formed on the inner surface of the base tube 11 as a coating film having a predetermined thickness. In this case, the reinforcing portion 22 is provided on the inner surface side of the base tube 11 and is disposed so as to protrude inward from the inner surface of the base tube 11.

  In addition, since this reinforcement part 22 is the same as the reinforcement part 21 of Example 2, and the composition etc., detailed description is abbreviate | omitted.

  In the fuel cell according to Example 3, a base tube 11 is formed by extrusion molding on the outer peripheral surface of a cylindrical mandrel (not shown), and a fuel electrode 12, a solid electrolyte 13, an interface is formed outside the base tube 11. After the connector 16 is laminated, the mandrel is removed from the base tube 11, the reinforcing portion 22 is laminated on the inner surface of the base tube 11, sintered (for example, held at 1350 ° C. to 1400 ° C. for 1 hour), and thereafter The air electrode 14 is formed into a film and sintered (for example, held at 1100 ° C. to 1300 ° C. for 1 hour). In this case, the fuel electrode 12, the solid electrolyte 13, the interconnector 16, and the reinforcing portion 22 form a slurry in which an organic solvent is mixed with the above-described powder material to form a uniform mixture, and the base tube 11 is formed by screen printing. A predetermined material is applied to a predetermined position on the outer surface and the inner surface.

  When an abnormality occurs during power generation by the fuel cell of this embodiment, for example, when the amount of fuel gas supplied into the base tube 11 is reduced, the pressure on the fuel electrode 12 side is reduced with respect to the air electrode 14 side. Differential pressure reversal phenomenon occurs. At this time, oxygen on the air electrode 14 side leaks to the fuel electrode 12 through a minute gap between the solid electrolyte 13 and the interconnector 16. Therefore, oxygen on the air electrode 14 side reaches the solid electrolyte 13, the interconnector 16, and the fuel electrode 12, and these are oxidized. However, since the reinforcing portion 22 is strong, the strength of the base tube 11 itself is increased. Therefore, the base tube 11 can sufficiently receive the stress acting from the reoxidized and expanded fuel electrode 12, and the base tube 11 is prevented from being damaged.

  Thus, in the fuel cell of Example 3, the power generation element 15 is formed by sequentially laminating the fuel electrode 12, the solid electrolyte 13, and the air electrode 14 on the outer surface of the cylindrical base tube 11, and this power generation A plurality of elements 15 are arranged at predetermined intervals in the axial direction of the base tube 11, and a plurality of power generating elements 15 are connected in series by an interconnector 16. A reinforcing portion 22 having a higher strength than the base tube 11 is provided corresponding to the boundary surface B between the solid electrolyte 13 and the solid electrolyte 13.

  Therefore, by providing the reinforcing portion 22 having higher strength than the base tube 11 corresponding to the boundary surface B between the interconnector 16 and the solid electrolyte 13 on the inner surface of the base tube 11, the rigidity of the base tube 11 itself is increased. Correspondence at the time of driving | operation becomes possible and robustness can be improved, As a result, damage to the base tube 11 can be prevented and durability and reliability can be improved.

  In Examples 2 and 3 described above, the reinforcing portions 21 and 22 are provided on the inner surface of the base tube 11, but may be provided on the outer surface of the base tube 11 as in the gas-impermeable layer 17 of the first example. Good.

  The fuel cell according to the present invention is provided with a gas-impermeable layer or a reinforcing portion corresponding to the boundary between the interconnector and the solid electrolyte, thereby improving robustness and preventing damage to the base tube. This is intended to improve reliability and can be applied to any type of fuel cell.

DESCRIPTION OF SYMBOLS 11 Base tube 12 Fuel electrode 13 Solid electrolyte 14 Air electrode 15 Power generation element 16 Interconnector 17 Gas impermeable layer (reinforcement part)
21, 22 Reinforcement part B Boundary surface (boundary part)

Claims (1)

A fuel electrode, a solid electrolyte, and an air electrode are sequentially laminated on the outer surface of a cylindrical base tube, and a plurality of power generation elements are arranged in the axial direction of the base tube, and the plurality of power generation elements Are connected in series by an interconnector,
A plurality of gas-impermeable layers are arranged on the outer surface of the base tube at a boundary portion between the interconnector and the solid electrolyte at a predetermined interval in the axial direction of the base tube,
Power generating element (hereinafter, referred to as the counter power device) having the solid electrolyte constituting the boundary portion facing the said gas impermeable layer on the outside of the gas impermeable layer with fuel electrode is provided, the gas impermeable layer A solid electrolyte of the power generation element next to the counter power generation element is provided adjacent to the counter power generation element, and the solid electrolyte of the counter power generation element is provided outside the fuel electrode of the counter power generation element ,
Adjacent gas impermeable layers are separated by a solid electrolyte, and the fuel electrodes forming the adjacent power generation elements are also separated by a solid electrolyte.
The fuel cell characterized by the above-mentioned.

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