JP2016146275A - Fuel battery single cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery single cell that can reduce the distribution of power generation within a cell surface as compared with a prior art.SOLUTION: A fuel battery single cell 1 comprises a zirconium type solid electrolytic layer 2, an anode 3, a cathode 4 containing Sr, and an intermediate layer 5 provided between the solid electrolytic layer 2 and the cathode 4. An entrance 310 for fuel gas is provided at the first end face 31 side of the anode 3, and an exit 320 for fuel gas is provided at the second end face 32 side which confronts the first end face 31 of the anode 3. The intermediate layer 5 contains a pattern forming portion 501 in which an intermediate layer material exists, and a pattern non-forming portion 502 in which the intermediate layer material does not exist, and is divided into plural regions 51 along a direction vertical to the flow direction F of the fuel gas. The pattern formation rate of each region 51 which is represented by the rate of the area of the pattern formation portion 501 contained in each area 51 to the area of each region 51 stepwise increases from the entrance 310 side of the fuel gas to the exit 320 side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell single cell, and more particularly to a fuel cell single cell using a solid electrolyte as an electrolyte.

2. Description of the Related Art Conventionally, a fuel cell single cell having an anode to which fuel gas is supplied, a zirconia-based solid electrolyte layer, and a cathode containing Sr and supplied with an oxidant gas is known. Further, a fuel having an intermediate layer provided between the solid electrolyte layer and the cathode in order to suppress high electric resistance SrZrO ₃ formed by the reaction of Zr and Sr at the interface between the solid electrolyte layer and the cathode. Battery cells are also known.

  As the fuel cell, for example, in Patent Document 1 described above, the porosity in the atmospheric porosity portion of the anode located on the downstream side in the fuel gas flow direction is located on the upstream side in the fuel gas flow direction. A solid oxide fuel cell unit cell formed larger than the porosity at the upstream side of the anode is disclosed.

JP 2012-94427 A

  A fuel cell single cell usually has different fuel gas consumption on the inlet side and outlet side of the fuel gas. Therefore, the fuel cell single cell tends to generate power generation in the cell plane. When a power generation distribution is generated in the cell plane, a temperature distribution is generated in the cell plane. When a temperature distribution is generated in the cell plane, a thermal stress is generated due to local power generation concentration, which tends to cause deterioration and cracking of the cell. Therefore, in the fuel cell single cell, it is required to reduce the power generation distribution in the cell plane.

  Note that the above-described technique for controlling the porosity of the anode in the fuel gas flow direction needs to form a pore distribution in the in-plane direction of the anode, which makes it difficult to manufacture the cell and is not practical.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a fuel cell single cell capable of reducing the power generation distribution in the cell plane as compared with the conventional art.

One embodiment of the present invention includes a zirconia-based solid electrolyte layer, an anode provided on the first surface side of the solid electrolyte layer, to which fuel gas is supplied, and a first surface of the solid electrolyte layer. A fuel which is provided on the second surface side on the opposite side and contains Sr and has a cathode to which an oxidant gas is supplied and an intermediate layer provided between the solid electrolyte layer and the cathode A single battery cell,
The fuel gas inlet is provided on the first end face side of the anode, and the fuel gas outlet is provided on the second end face side facing the first end face of the anode,
The intermediate layer is
A pattern forming portion in which the intermediate layer material exists and a pattern non-formed portion in which the intermediate layer material does not exist, and along a plane perpendicular to the flow direction of the fuel gas from the fuel gas inlet to the outlet Divided into multiple areas,
The pattern formation rate of each region represented by the ratio of the area of the pattern forming portion included in each region to the area of each region is a step from the fuel gas inlet side to the fuel gas outlet side. The fuel cell unit cell is characterized in that it becomes larger.

The intermediate layer of the fuel cell single cell includes a pattern forming portion where the intermediate layer material is present and a pattern non-forming portion where the intermediate layer material is not present. Therefore, in the single fuel cell, SrZrO ₃ having a high electric resistance is formed by the reaction between the cathode covering the intermediate layer and the solid electrolyte layer in the pattern non-formed part. The intermediate layer is divided into a plurality of regions along a plane perpendicular to the fuel gas flow direction, and the pattern formation rate of each region is directed from the fuel gas inlet side to the fuel gas outlet side. It is configured to increase gradually. Therefore, on the fuel gas inlet side, the cell resistance due to SrZrO ₃ increases, and the amount of fuel gas consumption is suppressed, making it difficult to generate power. On the other hand, on the fuel gas outlet side, the cell resistance due to SrZrO ₃ is lowered, and the consumption amount of the fuel gas is increased to facilitate power generation. In other words, the fuel cell single cell is intended to make power generation uniform by actively utilizing the high electrical resistance layer that has been actively excluded in the past.

  Therefore, according to the present invention, it is possible to obtain a fuel cell single cell capable of reducing the power generation distribution in the cell plane as compared with the prior art.

1 is a schematic cross-sectional view of a fuel cell single cell of Example 1. FIG. FIG. 3 is a view of an intermediate layer in a single fuel cell of Example 1 as viewed from the cathode side. It is an enlarged view of the entrance area | region which comprises some intermediate | middle layers shown by FIG. FIG. 3 is an enlarged view of an intermediate region constituting a part of the intermediate layer shown in FIG. 2. It is an enlarged view of the exit area | region which comprises some intermediate | middle layers shown by FIG. It is explanatory drawing for demonstrating the width | variety of a pattern formation part and the width | variety of a pattern non-formation part. FIG. 4 is a view of an intermediate layer in a single fuel cell of Example 2 as viewed from the cathode side. It is a simulation result of case 1-2, case 2, and case 3 in an experimental example. It is a simulation result of case 1-1, case 1-2, case 1-3, case 1-4, and case 3 in an experimental example.

  The fuel cell unit cell is a solid electrolyte type fuel cell unit cell that uses a solid electrolyte as an electrolyte. As the solid electrolyte constituting the solid electrolyte layer, a solid oxide ceramic exhibiting oxygen ion conductivity can be used. A fuel cell using solid oxide ceramics as a solid electrolyte is called a solid oxide fuel cell (SOFC).

  The fuel cell unit cell can have a flat battery structure from the viewpoint of high power generation performance. Specifically, the fuel cell unit cell may have a shape such as a quadrangular shape having a predetermined cell thickness. The fuel cell unit cell may be an anode support type in which an anode as an electrode is a support. When the technology for providing pore distribution in the fuel gas flow direction or the technology for changing the conductivity by changing the material in the fuel gas flow direction is applied to an anode-supported fuel cell single cell, the anode as a support The strength of the anode decreases, and the manufacture of the anode becomes complicated. On the other hand, the fuel cell single cell uses the high electric resistance layer generated in the pattern non-formed part in the intermediate layer to achieve uniform power generation. For this reason, the fuel cell single cell has a low need to change the configuration of the anode serving as the support in order to reduce the power generation distribution in the cell plane. Therefore, in this case, the unevenness of the strength of the anode as the support hardly occurs, and the manufacture of the anode is difficult to be complicated.

  The fuel cell single cell preferably employs a method in which fuel gas and oxidant gas flow in a uniaxial direction.

  In this case, it is possible to obtain a fuel cell single cell that easily reduces the power generation distribution in the cell plane that occurs in the uniaxial direction. Specifically, the fuel gas and the oxidant gas flow in the uniaxial direction include a parallel flow method in which the fuel gas and the oxidant gas flow in the same direction in the cell plane, and the fuel gas and the oxidant gas flow in the cell. A counterflow system that flows in the reverse direction in the plane can be exemplified. More preferably, the fuel cell single cell adopts a parallel flow system from the viewpoint of ease of reduction of power generation distribution, gas sealability, and the like.

  In the parallel flow method, an oxidant gas inlet is disposed on the first end face side of the cathode (same side as the first end face side of the anode) and the second end face facing the first end face of the cathode. An oxidant gas outlet is disposed on the end face side (the same side as the second end face side of the anode). In the counter flow system, an oxidant gas inlet is disposed on the second end face side of the cathode, and an oxidant gas outlet is disposed on the first end face side of the cathode. As the fuel gas, for example, a gas mainly composed of hydrogen gas, methane gas, or the like can be used. As the oxidant gas, for example, oxygen gas, air gas, or the like can be used.

Specifically, the intermediate layer material constituting the intermediate layer is, for example, CeO ₂ , CeO ₂ , Gd, Sm, Y, La, Nd, Yb, Ca, Dr, and Ho, or one kind selected from Ho Examples thereof include cerium oxide-based oxides such as ceria-based solid solutions doped with two or more elements. The thickness of the intermediate layer is preferably 1 to 10 μm, more preferably 1 to 5 μm, from the viewpoints of reducing ohmic resistance, suppressing element diffusion from the cathode, and the like.

  The intermediate layer includes a pattern forming portion in which the intermediate layer material exists and a pattern non-formed portion in which the intermediate layer material does not exist. Specifically, for example, the pattern forming portion can be composed of a plurality of dot portions formed from an intermediate layer material. Specifically, for example, the dot portions can have a prismatic shape, a cylindrical shape, or the like, and can be separated from each other. On the other hand, the pattern non-formation part can specifically be constituted by gaps formed between a plurality of dot parts, for example. In the intermediate layer, the pattern forming portion can have regularity, for example, by regularly arranging a plurality of dot portions. In this case, it becomes easy to reduce the power generation distribution in the cell plane.

  In the region including the pattern forming portion and the pattern non-forming portion, the minimum value of the width of the pattern forming portion can be 100 μm or more. In this case, the balance of securing the pattern forming portion, the formability of the pattern forming portion, and the Sr diffusion suppressing effect is excellent. The minimum value of the width of the pattern forming portion is preferably 200 μm or more, more preferably 300 μm or more, and even more preferably 500 μm or more. The minimum value of the width of the pattern forming portion is preferably 2000 μm or less, more preferably 1500 μm or less, and even more preferably 1000 μm from the viewpoints of securing the pattern non-forming portion and reducing the fuel gas concentration distribution accompanying local power generation distribution. It can be as follows. Further, the width of the pattern non-formed part can be set to 50 to 500 μm. In this case, it becomes easy to ensure the effect of reducing the power generation distribution in the cell plane. Further, it can be easily handled by a method such as a screen printing method, and there is an advantage that a range of methods can be selected. The width of the pattern-unformed part is preferably 75 μm or more, more preferably 100 μm or more. The width of the pattern non-formed part is preferably 400 μm or less, more preferably 300 μm or less, and still more preferably 200 μm or less from the viewpoint of securing the area of the pattern forming part. The width can be measured by viewing the intermediate layer from the cathode side surface.

  The intermediate layer is divided into a plurality of regions along a plane perpendicular to the fuel gas flow direction from the fuel gas inlet to the outlet. Specifically, the intermediate layer is preferably 2 to 10 regions, more preferably 2 to 8 regions, from the viewpoints of, for example, the effect of reducing the power generation distribution in the cell plane and the ease of forming the intermediate layer. More preferably, it can be divided into 3 to 5 regions.

  The intermediate layer may be equally divided or may not be equally divided. Specifically, the intermediate layer has, for example, the division ratio of the region closest to the fuel gas inlet in each region (sometimes referred to as an “inlet side region”) at the fuel gas outlet. The area can be divided so as to be smaller than the division ratio of the area in the vicinity (sometimes referred to as “exit side area”). The amount of fuel gas supplied to the anode portion corresponding to the inlet side region is relatively large. Therefore, power generation concentration tends to be high in the entrance side region. Therefore, when configured as described above, it is easy to effectively suppress power generation concentration in the inlet side region, and it is easy to reduce the power generation distribution in the cell plane without significantly reducing the power generation amount. More specifically, the split ratio of the intermediate layer can be configured to increase from the fuel gas inlet side toward the fuel gas outlet side, for example. In this case, it becomes easier to obtain the above-described effects.

  In the intermediate layer, the pattern formation rate of each region represented by the ratio of the area of the pattern forming portion included in each region to the area of each region is gradually increased from the fuel gas inlet side to the fuel gas outlet side. growing. Specifically, such an intermediate layer is formed by, for example, forming a material for forming an intermediate layer on the surface of the solid electrolyte layer by a printing method such as a screen printing method using a mask in which a predetermined pattern is formed, It can be formed relatively easily by firing. The area on the cathode side is used as the area for calculating the pattern formation rate.

  Here, the pattern formation rate of the entrance side region among the above regions can be specifically set within a range of 50 to 80%, for example. In this case, the balance between securing the amount of power generation and reducing the power generation distribution in the cell plane is good. The pattern formation rate in the inlet side region is preferably 55% or more, and more preferably 60% or more, from the viewpoint of improving the amount of power generation and reducing the power generation distribution in the cell plane. The pattern formation rate in the inlet side region is preferably 75% or less, more preferably 70% or less, from the viewpoint of reducing the power generation distribution in the cell plane.

  Moreover, the pattern formation rate of an exit side area | region among said each area | region can specifically be in the range of 95-100%, for example. In this case, it becomes easier to secure the amount of power generation. The pattern formation rate of the exit side region can be preferably 96% or more, more preferably 98% or more, and even more preferably 100% (that is, the exit side region does not include a pattern non-formed part). .

  Examples of the material constituting the solid electrolyte layer, the anode, and the cathode in the single fuel cell include the following.

  As the solid electrolyte layer material, zirconium oxide-based oxides such as yttria-stabilized zirconia (YSZ) and scandia-stabilized zirconia (ScSZ) can be suitably used from the viewpoint of excellent strength and thermal stability. As the solid electrolyte layer material, yttria-stabilized zirconia is preferable from the viewpoints of ion conductivity, mechanical stability, compatibility with other materials, and chemical stability from an air atmosphere to a fuel gas atmosphere. The thickness of the solid electrolyte layer is preferably 3 to 20 μm, more preferably 5 to 15 μm, from the viewpoint of reducing ohmic resistance.

  Examples of the anode material include a mixture of a catalyst such as Ni or NiO and a solid electrolyte such as the above-described zirconium oxide-based oxide. NiO becomes Ni in a reducing atmosphere during power generation. From the viewpoint of gas diffusion, electrical resistance, strength, etc., the thickness of the anode is preferably 100 to 800 μm, more preferably 200 to 700 μm, for example. The anode may be composed of a single layer or may be composed of a plurality of layers. When the anode is composed of a plurality of layers, specifically, the anode includes, for example, an active layer disposed on the solid electrolyte layer side and a diffusion layer disposed on the side of the active layer opposite to the solid electrolyte layer side. It can be set as the structure provided. The active layer is mainly a layer for enhancing the electrochemical reaction on the anode side. The diffusion layer is a layer capable of diffusing the supplied fuel gas.

As the cathode material, for example, a perovskite oxide containing Sr, a mixture of a perovskite oxide containing Sr and a solid electrolyte, or the like can be preferably used. Specific examples of the perovskite oxide containing Sr include La _1-x Sr _x Co _1-y Fe _y O ₃ -based oxides (x = 0.4, y = 0.8, etc.), La _1-x Sr _x CoO ₃ system oxide (x = 0.4, etc.), La _1-x Sr _x FeO ₃ system oxide (x = 0.4, etc.), La _1-x Sr _x MnO ₃ system oxidation Examples of such materials (x = 0.4, etc.), Sm _1-x Sr _x CoO ₃ oxides (x = 0.5, etc.), etc. These can be used alone or in combination of two or more. Of the perovskite oxides containing Sr, La _1-x Sr _x Co _1-y Fe _y O ₃ is preferable from the viewpoint of high catalytic activity even at low temperature operation (eg, about 600 to 700 ° C.). Preference is given to oxides such as La _1-x Sr _x CoO ₃ oxides and Sm _1-x Sr _x CoO ₃ oxides. In the composition formula of the perovskite oxide, the atomic ratio of oxygen is represented as 3. As is apparent to those skilled in the art, for example, when the atomic ratio x (y) is not 0, In reality, the atomic ratio of oxygen often takes a value smaller than 3 because holes are formed. However, since the number of oxygen vacancies varies depending on the type of element to be added and the manufacturing conditions, the oxygen atomic ratio is represented as 3 for the sake of convenience (the same applies hereinafter).

Moreover, as a solid electrolyte that can be used in combination with a perovskite oxide containing Sr, Y ₂ O ₃ , Sc ₂ O ₃ , Gd ₂ O ₃ , Sm ₂ O ₃ , Yb ₂ from the viewpoint of oxygen ion conductivity and the like. Zirconium oxide-based oxides such as stabilized zirconia (including partially stabilized zirconia, hereinafter omitted) including one or more rare earth oxides such as O ₃ and Nd ₂ O ₃ , CeO ₂ , and the above-mentioned ceria-based solid solution Etc. can be illustrated.

  The thickness of the cathode is preferably 20 to 100 μm, more preferably 30 to 80 μm, from the viewpoints of gas diffusibility, electrode reaction resistance, current collection, and the like.

Specifically, for example, the cathode may be formed by forming a material for forming a cathode on the surface of the intermediate layer by a printing method such as a screen printing method and baking the material. In this case, at the time of forming the cathode, the cathode forming material easily enters the unpatterned portion of the intermediate layer. As a result, a part of the cathode is filled in the unpatterned portion, the cathode and the solid electrolyte layer are easily in contact with each other, and SrZrO ₃ is easily formed.

  In addition, each structure mentioned above can be arbitrarily combined as needed, in order to acquire each effect etc. which were mentioned above.

  Hereinafter, the fuel cell single cell of an Example is demonstrated using drawing. In addition, about the same member, it demonstrates using the same code | symbol.

Example 1
The fuel cell single cell of Example 1 is demonstrated using FIGS. As shown in FIGS. 1 to 5, the fuel cell unit cell 1 of this example is provided on the zirconia-based solid electrolyte layer 2 and the first surface side of the solid electrolyte layer 2, and is supplied with fuel gas. An anode 3 that is provided, a cathode 4 that is provided on the second surface side opposite to the first surface of the solid electrolyte layer 2 and that contains Sr and is supplied with an oxidant gas, and a solid electrolyte layer 2 and an intermediate layer 5 provided between the cathode 4.

  In this example, specifically, the fuel cell single cell 1 is a flat single cell having the anode 3 as a support. The fuel gas supplied to the anode 3 is hydrogen gas, and the oxidant gas supplied to the cathode 4 is air gas. The single fuel cell 1 employs a method in which fuel gas and oxidant gas flow in a uniaxial direction. Specifically, a parallel flow method in which fuel gas and oxidant gas flow in the same direction in the cell plane. It is said that. In the figure, symbol F indicates the flow direction of the fuel gas, and symbol O indicates the flow direction of the oxidant gas.

  Specifically, in this example, the solid electrolyte layer 2 is formed in a square shape having a thickness of 10 μm, a size of 100 mm in the same direction as the fuel gas flow direction F, and a size of 100 mm in the direction perpendicular to the fuel gas flow direction F. Has been. Similarly, the anode 3 is formed in a rectangular shape having a thickness of 450 μm, a size of 100 mm in the same direction as the fuel gas flow direction F, and a size of 100 mm in the direction perpendicular to the fuel gas flow direction F. The cathode 4 is formed in a square shape having a thickness of 50 μm, a size of 90 mm in the same direction as the fuel gas flow direction F, and a size of 90 mm in the direction perpendicular to the fuel gas flow direction F. The intermediate layer 5 is formed in a square shape having a thickness of 5 μm, a size of 90 mm in the same direction as the fuel gas flow direction F, and a size of 90 mm in the direction perpendicular to the fuel gas flow direction F.

In this example, the solid electrolyte layer 2 is formed from a zirconium oxide-based oxide. Specifically, the zirconium oxide-based oxide is yttria-stabilized zirconia (hereinafter, 8YSZ) containing 8 mol% of Y ₂ O ₃ . The anode 3 is formed in layers from a mixture of a catalyst and a solid electrolyte. Specifically, the solid electrolyte constituting the anode 3 is 8YSZ which is a zirconium oxide-based oxide. Specifically, the catalyst constituting the anode 3 is Ni or NiO. The volume ratio of catalyst to solid electrolyte is 50/50. The cathode 4 is formed in a layer form from a perovskite oxide containing Sr. Perovskite oxide, _{specifically, La 1-x Sr x Co} 1-y Fe y O 3 (x = 0.4, y = 0.8, or less, LSCF) it is. The intermediate layer 5 is made of a cerium oxide-based oxide. The cerium oxide-based oxide is specifically ceria doped with 10 mol% of Gd (hereinafter, 10 GDC).

  In the single fuel cell 1, a fuel gas inlet 310 is provided on the first end face 31 side of the anode 3. A fuel gas outlet 320 is provided on the second end face 32 side facing the first end face 31 of the anode 3.

  The intermediate layer 5 includes a pattern forming portion 501 where the intermediate layer material is present and a pattern non-forming portion 502 where the intermediate layer material is not present. The intermediate layer 5 is divided into a plurality of regions 51 along a plane perpendicular to the fuel gas flow direction F from the fuel gas inlet 310 to the outlet 320. The pattern formation rate of each region 51 represented by the ratio of the area of the pattern forming portion 501 included in each region 51 to the area of each region 51 is from the fuel gas inlet 310 side to the fuel gas outlet 320 side. It is getting bigger step by step.

  In this example, specifically, the intermediate layer 5 is divided into three along a plane perpendicular to the fuel gas flow direction F. Hereinafter, for convenience of explanation, the region 51 closest to the fuel gas inlet 310 is referred to as an inlet side region 511, and the region 51 closest to the fuel gas outlet 320 is referred to as an outlet side region 513. Further, a region 51 sandwiched between the inlet side region 511 and the outlet side region 513 is referred to as an intermediate region 512. In this example, the number of intermediate regions 512 is one, but a plurality of intermediate regions 512 may be arranged. The division ratio of the inlet side region 511, the intermediate region 512, and the outlet side region 513 is 1: 1: 1. That is, in this example, each area of the entrance side region 511, the intermediate region 512, and the exit side region 513 is the same. However, the pattern formation rates of the inlet side region 511, the intermediate region 512, and the outlet side region 513 are different, and the pattern formation rate of the inlet side region 511 <the pattern formation rate of the intermediate region 512 <the outlet side region 513. The pattern formation rate relationship is satisfied. In this example, the pattern formation rate of the entrance region 511 is 60%, and the pattern formation rate of the intermediate region 512 is 80%. Therefore, both the entrance side region 511 and the intermediate region 512 include the pattern forming portion 501 and the pattern non-forming portion 502. On the other hand, the pattern formation rate of the outlet side region 513 is 100%. That is, as shown in FIG. 5, the exit side region 513 does not include the pattern non-formed portion 502, and the entire region is configured by the pattern forming portion 501.

  Specifically, in the entrance side region 511 and the intermediate region 512, the pattern forming unit 501 is composed of a plurality of dot portions 501a formed of an intermediate layer material, as shown in FIGS. The dot portions 501a have a quadrangular prism shape and are separated from each other. The plurality of dot portions 501a are regularly arranged at regular intervals in a direction perpendicular to the fuel gas flow direction F and the fuel gas flow direction F, respectively. The pattern non-formation part 502 is comprised from the clearance gap 502a formed between the some dot parts 501a arrange | positioned as mentioned above.

  More specifically, as shown in FIG. 3, the entrance-side region 511 has a dimension d1 = 1 mm, a dimension d2 = 1 mm, a dimension d3 = 290 μm, a dimension d4 = 290 μm, and a dimension d5 = 410 μm. More specifically, as shown in FIG. 4, the intermediate region 512 has a dimension d1 = 1 mm, a dimension d2 = 1 mm, a dimension d3 = 120 μm, a dimension d4 = 120 μm, and a dimension d5 = 170 μm. Therefore, in this example, the minimum value of the width of the pattern forming portion 501 is 1 mm. Further, the minimum value of the width of the pattern non-formed portion 502 is 120 μm, and the width of the pattern non-formed portion 502 is 170 μm.

  For example, as shown in FIG. 6, when the pattern forming portion 501 has an uneven portion on the outer peripheral portion, the minimum value of the width of the pattern forming portion 501 is x1 in the drawing. The minimum value of the width of the pattern non-formed part 502 is y1 in the figure, and the maximum value of the width of the pattern non-formed part 502 is y2 in the figure.

  The fuel cell single cell 1 of this example can be manufactured as follows, for example.

  A sheet-like anode forming material and a sheet-like solid electrolyte layer forming material are laminated in this order to obtain a laminate. In addition, the laminated body can be crimped or degreased by a CIP molding method or the like. The obtained laminate is co-fired at a temperature of about 1250 to 1500 ° C. Thereby, a sintered body in which the anode 3 and the solid electrolyte layer 2 are laminated in this order is obtained. A pasty intermediate layer forming material is applied to the outer surface of the solid electrolyte layer 2 in the obtained sintered body by a screen printing method or the like so that the intermediate layer 5 having a predetermined pattern is formed. The laminate on which the intermediate layer forming material is applied is fired at a temperature of about 1000 to 1500 ° C. Thereby, the intermediate layer 5 is formed on the outer surface of the solid electrolyte layer 2. A paste-like cathode forming material is applied to the surface of the intermediate layer 5 by a screen printing method or the like, and baked at a temperature of about 900 to 1200 ° C. Thereby, the cathode 4 is formed on the surface of the intermediate layer 5. Thus, the fuel cell single cell 1 is obtained.

  Next, the effect of the fuel cell single cell of this example is demonstrated.

The intermediate layer 5 of the fuel cell single cell 1 of this example includes a pattern forming portion 501 where the intermediate layer material is present and a pattern non-forming portion 502 where the intermediate layer material is not present. Therefore, in the single fuel cell 1 of the present example, the cathode 4 covering the intermediate layer 5 reacts with the solid electrolyte layer 2 in the unpatterned portion 502, thereby forming SrZrO ₃ having high electrical resistance. . The intermediate layer 5 is divided into a plurality of regions 51 along a plane perpendicular to the fuel gas flow direction F, and the pattern formation rate of each region 51 is determined from the fuel gas inlet 310 side to the fuel gas. It is configured to increase stepwise toward the outlet 320 side. Therefore, on the fuel gas inlet 310 side, the cell resistance due to SrZrO ₃ increases, and the amount of fuel gas consumption is suppressed, making it difficult to generate power. On the other hand, on the fuel gas outlet 320 side, the cell resistance due to SrZrO ₃ is lowered, and the amount of consumption of the fuel gas is increased to facilitate power generation. That is, in the fuel cell single cell 1 of this example, the power generation is made uniform by positively using the high electrical resistance layer that has been positively excluded conventionally. Therefore, the fuel cell single cell 1 of this example can reduce the power generation distribution in the cell plane as compared with the conventional case.

(Example 2)
A single fuel cell of Example 2 will be described with reference to FIG. As shown in FIG. 7, in the fuel cell single cell 1 of this example, the intermediate layer 5 is configured such that, in each region 51, the division ratio of the inlet side region 511 is smaller than the division ratio of the outlet side region 513. It is divided into Specifically, the split ratio of the intermediate layer 5 is configured to increase from the fuel gas inlet 310 side toward the fuel gas outlet 320 side. More specifically, in this example, the division ratio of the inlet side region 511, the intermediate region 512, and the outlet side region 513 is 1: 2: 3. In addition, the pattern formation rate of each area | region is the same as that of Example 1, and the other structure is also the same as that of Example 1. FIG.

  The amount of fuel gas supplied to the anode 3 portion corresponding to the inlet side region 511 is relatively large. Therefore, the power generation concentration tends to be high in the inlet side region 511. Therefore, when configured as in this example, it is easy to effectively suppress power generation concentration in the inlet side region 511, and it is easy to reduce the power generation distribution in the cell plane without significantly reducing the power generation amount. . In particular, in this example, since the split ratio of the intermediate layer 5 is configured to increase from the fuel gas inlet 310 side toward the fuel gas outlet 320 side, the above-described effects can be easily obtained. Other functions and effects are the same as those of the first embodiment.

<Experimental example>
Hereinafter, it demonstrates more concretely using an experiment example.
A simulation was conducted to investigate the power generation distribution in the cell plane of a single fuel cell. This will be described.

(Case 1-1)
In the single fuel cell of Example 1, the same except that the pattern formation rate of the inlet side region 511 is 50%, the pattern formation rate of the intermediate region 512 is 80%, and the pattern formation rate of the outlet side region 513 is 100%. Thus, a fuel cell single cell of case 1-1 was obtained.

(Case 1-2)
The single fuel cell of Example 1 was used as the single fuel cell of Case 1-2. Therefore, in this case, the pattern formation rate of the entrance region 511 is 60%, the pattern formation rate of the intermediate region 512 is 80%, and the pattern formation rate of the exit region 513 is 100%.

(Case 1-3)
In the single fuel cell of Example 1, the pattern formation rate of the inlet side region 511 is 70%, the pattern formation rate of the intermediate region 512 is 80%, and the pattern formation rate of the outlet side region 513 is 100%. Thus, a single fuel cell of Case 1-3 was obtained.

(Case 1-4)
In the single fuel cell of Example 1, the pattern formation rate of the inlet side region 511 is 80%, the pattern formation rate of the intermediate region 512 is 80%, and the pattern formation rate of the outlet side region 513 is 100%. Thus, a single fuel cell of Case 1-4 was obtained.

(Case 2)
The fuel cell single cell of Example 2 was used as the fuel cell single cell of Case 2.

(Case 3)
In the single fuel cell of the first embodiment, the intermediate layer 5 does not include the pattern non-formed portion 502, and the intermediate layer 5 is uniformly intermediate from the fuel gas inlet 310 side toward the fuel gas outlet 320 side. The fuel cell single cell of Case 3 was made in the same manner except that the layer material was used.

For each case set as described above, the fuel gas when the power generation rate is 0.25 A / cm ^{2 with} the fuel gas utilization rate being 75% and the oxidant gas air gas utilization rate being 30%. The relationship between the distance from the inlet 310 and the power generation ratio (%) was calculated. The power generation ratio (%) is a value calculated from the power generation amount of each part / the total power generation amount × 100 when the power generation surface is equally divided into 10 mm pitches in the fuel gas flow direction. The fuel gas and air gas were assumed to flow uniformly in the cell plane. It was also assumed that there was no temperature effect due to heat generation during power generation. In addition, it is assumed that no power generation occurs in a portion corresponding to the pattern non-formed portion 502. The simulation results for each case are shown in Table 1, FIG. 8 and FIG. The power generation ratio (MAX / MIN) shown in Table 1 is a value of (maximum value of power generation ratio) / (minimum value of power generation ratio), and means a power generation distribution in the cell plane. In addition, the power generation amount and the power generation area of each case are values when the power generation amount of case 3 as a comparison is 1 and the power generation area is 1.

  According to the simulation result, the following can be understood. First, the fuel cell single cells of Case 1-2, Case 2, and Case 3 are compared. As shown in Table 1 and FIG. 8, the fuel cell single cells of Case 1-2 and Case 2 generate power without significantly reducing the amount of power generation compared to the single fuel cell of Case 3 corresponding to the conventional example. It was confirmed that the ratio (MAX / MIN) was reduced. From this result, it can be seen that the fuel cell single cells of case 1-2 and case 2 can reduce the power generation distribution in the cell plane as compared with the conventional case.

  Next, the fuel cell single cells of case 1-1, case 1-2, case 1-3, case 1-4, and case 3 are compared. As shown in Table 1 and FIG. 9, when the pattern formation rate of the inlet side region 511 decreases, the power generation ratio (MAX / MIN) tends to increase. Moreover, when the pattern formation rate of the entrance area 511 increases, the power generation ratio (MAX / MIN) tends to increase. From this result, the pattern formation rate of the entrance side region 511 is in the range of 50% to 80%, preferably more than 50% to less than 80%, more preferably in the range of 60% to 70%. It can be seen that the power generation distribution in the cell plane can be further reduced.

  As mentioned above, although the Example of this invention was described in detail, this invention is not limited to the said Example, A various change is possible within the range which does not impair the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Fuel cell single cell 2 Solid electrolyte layer 3 Anode 31 1st end surface 32 2nd end surface 310 Fuel gas inlet 320 Fuel gas outlet 4 Cathode 5 Intermediate layer 501 Pattern formation part 502 Pattern non-formation part 51 Area | region F Fuel gas Flow direction

Claims (8)

A zirconia-based solid electrolyte layer (2), an anode (3) provided on the first surface side of the solid electrolyte layer (2), to which fuel gas is supplied, and the solid electrolyte layer (2) A cathode (4) provided on the second surface side opposite to the first surface and containing Sr and supplied with an oxidant gas, the solid electrolyte layer (2), and the cathode (4 A fuel cell single cell (1) having an intermediate layer (5) provided between
The fuel gas inlet (310) is provided on the first end face (31) side of the anode (3), and the second end face (32) facing the first end face (31) of the anode (3). ) Side is provided with the fuel gas outlet (320),
The intermediate layer (5)
The fuel gas including a pattern forming portion (501) in which the intermediate layer material is present and a pattern non-formed portion (502) in which the intermediate layer material is not present and traveling from the fuel gas inlet (310) to the outlet (320) Are divided into a plurality of regions (51) along a plane perpendicular to the flow direction (F) of
The pattern formation rate of each region (51) represented by the ratio of the area of the pattern formation portion (501) included in each region (51) to the area of each region (51) is the inlet of the fuel gas. A fuel cell single cell (1), which gradually increases from the (310) side toward the fuel gas outlet (320) side.   The pattern formation rate of a region (51) located closest to the fuel gas inlet (310) among the regions (51) is in a range of 50 to 80%. 1. A fuel cell single cell (1) according to 1.   The pattern formation rate of a region (51) located closest to the fuel gas outlet (320) among the regions (51) is in a range of 95 to 100%. A single fuel cell (1) according to 1 or 2.   Of the regions (51), the division ratio of the region (51) closest to the fuel gas inlet (310) is the region (51) closest to the fuel gas outlet (320). The fuel cell single cell (1) according to any one of claims 1 to 3, characterized in that the fuel cell single cell (1) is smaller than a split ratio.   The division ratio of the intermediate layer (5) increases from the fuel gas inlet (310) side toward the fuel gas outlet (320) side. The fuel cell single cell (1) described in 1.   In the region (51) including the pattern formation part (501) and the pattern non-formation part (502), the minimum value of the width of the pattern formation part (501) is 100 μm or more, and the pattern non-formation part ( The fuel cell single cell (1) according to any one of claims 1 to 5, characterized in that the width of 502) is in the range of 50 to 500 µm.   The fuel cell single cell (1) according to any one of claims 1 to 6, wherein the fuel gas and the oxidant gas flow in a uniaxial direction.   The fuel cell single cell (1) according to any one of claims 1 to 7, wherein the anode (3) is a support.

Images