JP5240700B2 - Fuel cell stack and manufacturing method thereof - Google Patents

Description

The present invention relates to a fuel cell stack and a manufacturing how to generate power by utilizing the properties of the solid electrolyte.

Conventionally, a solid electrolyte fuel cell (solid oxide fuel cell: hereinafter also referred to as SOFC) using a solid electrolyte (solid oxide) is known as a fuel cell.
In this SOFC, normally, a plurality of solid electrolyte fuel cell cells (single cells) each having a fuel electrode and an air electrode on each surface of a solid electrolyte membrane (layer) are used. In other words, a stack is formed by stacking a large number of solid oxide fuel cells, and fuel gas is supplied to the fuel electrode, air is supplied to the air electrode, and the fuel (for example, hydrogen) and oxygen in the air are supplied to the solid electrolyte. Electric power is generated by chemical reaction through the layers.

  The solid oxide fuel cell is roughly classified into a self-supporting membrane cell and a support membrane cell. Among these, as the support membrane type cell, a so-called anode support type cell in which a solid electrolyte layer is formed on a fuel electrode substrate is common.

  In addition to the plate-like body, as the solid electrolyte fuel cell, a solid electrolyte layer is formed outside a cylindrical air electrode (inner electrode) as described in Patent Document 1, for example, and the solid electrolyte layer A cylindrical body in which a fuel electrode (outer electrode) is formed outside is proposed.

  In the technique of this patent document 1, the external electrode is formed thin, but since the outer electrode is used as a current path for current collection, the path for taking out the current becomes long and the internal resistance increases. It was.

On the other hand, in the technique of Patent Document 2 that has been developed in recent years, a continuous solid phase matrix that is a current collecting material continuous on the outer periphery of the outer electrode is used, which improves the current collecting characteristics, specifically, the internal resistance. Reduction can be expected.
Japanese Patent No. 3217695 JP 2005-518075 gazette

However, the technique of Patent Document 2 has a problem in that the positioning accuracy of the fuel cell is poor because the cylindrical fuel cell is immersed in the slurry of the continuous solid phase matrix.
In addition, although there is an effect of improving the current collecting characteristics, there is a problem that it is disadvantageous in terms of gas diffusion. That is, if the gas diffusion performance is low, the power generation performance is low, which is not preferable.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to facilitate the positioning of a fuel cell, for example, a fuel cell stack having a high power generation performance and the like and an excellent gas diffusion performance. and to provide a manufacturing how.

a) First, each claim of the fuel cell stack and the manufacturing method thereof will be described.
(1) In the invention of claim 1, a plurality of cylindrical fuel cell portions each having a cylindrical inner electrode and a cylindrical solid electrolyte layer formed on the outer peripheral surface thereof are arranged in parallel (for example, in parallel). The fuel cell layered portion is sandwiched between conductive plates made of porous conductive ceramics in the thickness direction, and between the solid electrolyte layer and the conductive plate-like body. The gist of the fuel cell stack is provided with an outer electrode of the fuel cell portion.

In the present invention, the fuel cell layer portion in which a plurality of cylindrical inner electrode (hence the tubular fuel cell unit) in parallel (e.g. parallel), with the structure interposing a conductive plate (current collector) Therefore, it is easy to arrange a plurality of inner electrodes (and hence the fuel cell portion) in a uniform manner, and the positioning accuracy of the inner electrodes (and hence the fuel cell portion) can be increased. That is, there is an effect that the positioning accuracy of the fuel cell is higher than that of the conventional technique in which the fuel cell is immersed in the slurry.

Further, there is an advantage that gas permeability can be secured while maintaining the activity of the outer electrode of the solid electrolyte layer (that is, the structure can be changed between the outer electrode and the conductive plate).
Here, the fuel cell section is provided with an inner electrode and a solid electrolyte layer, and a fuel cell (cell) is provided with an outer electrode. Further, the fuel cell portion has a cylindrical shape (preferably a cylindrical shape), and the outer diameter thereof can be 3 mm or less (in the case of a polygon, an ellipse or the like, the maximum outer diameter).

  (2) In the invention of claim 2, the conductive plate-like body includes a plurality of parallel grooves into which the fuel cell part is fitted, and the fuel cell part is fitted into the groove. It is characterized by being sandwiched and fixed between conductive plate-like bodies.

  In the present invention, the fuel cell portion is fitted into each of the plurality of parallel grooves on the surface of the conductive plate-like body, and the plurality of fuel cell portions are sandwiched by the conductive plate-like body from both sides thereof, so that the fuel cell portion is firmly fixed. it can.

(3) The invention of claim 3 is characterized in that the conductive plate has a gas permeability coefficient of 5 × 10 ⁻⁵ cm ² · sec ⁻¹ · Pa ⁻¹ or more.
When the conductive plate has this gas permeability coefficient, the amount of introduced gas is ensured, and the advantage of a highly integrated structure (advantage that it can be compact and can realize a sufficient output density even at low temperatures) is obtained. It is done.

In other words, in the present invention, the conductive plate has a high gas permeability coefficient, and a fuel cell stack having a structure with a high integration density and a resistance to thermal cycling can be realized.
For example, when an output density of 2 W / cm ³ is achieved in a cylindrical fuel cell held by a cubic conductive plate having a thickness of about 1 cm, as shown by an oblique solid line in FIG. When a differential pressure of 0.2 MPa or more is set on the gas inlet side and outlet side of the plate-like body, and further considering the cooling of the fuel cell, when the utilization rate of the introduced gas is 30%, the gas permeability coefficient is If it is 5 × 10 ⁻⁵ cm ² · sec ⁻¹ · Pa ⁻¹ or more, the amount of gas introduced and filled is sufficient, and the above-described advantages of the highly integrated structure can be obtained.

FIG. 13 shows the relationship between the amount of gas that can be permeated and the amount of gas necessary for power generation with respect to the gas permeability coefficient. That is, it is a graph showing the required amount of air calculated from the amount of current assumed to obtain 2 W / cm ³ in a 1 cm ³ cubic cell and the amount of gas that can permeate at each gas permeability coefficient. In addition, the vertical axis | shaft of FIG. 13 is the gas amount per unit time, a horizontal axis is a gas permeation coefficient, and the required amount of _air was calculated in the air utilization factor (Efair) 30% also considering the cooling of the cubic cell. .

(4) The invention of claim 4 is characterized in that the conductive plate has a gas permeability coefficient of 1 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more.
For example, when an output density of 2 W / cm ³ is achieved in a cylindrical fuel cell held by a cubic conductive plate having a thickness of about 1 cm, as shown by an oblique broken line in FIG. When a differential pressure of 0.1 MPa or more is set on the gas inlet side and outlet side of the plate-like body and the utilization rate of the introduced gas is 30% in consideration of cooling of the fuel cell, the gas permeability coefficient is When it is 1 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more, the amount of gas introduced and filled is sufficient, and the above-described advantages of the highly integrated structure can be obtained.

(5) The invention of claim 5 is characterized in that the conductive plate has a gas permeability coefficient of 5 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more.
For example, in the case of achieving a power density of 2 W / cm ³ in a cylindrical fuel cell held by a cubic conductive plate having a thickness of about 1 cm, as shown by an oblique alternate long and short dash line in FIG. When the differential gas pressure of 0.02 MPa or more is set on the gas inlet side and outlet side of the porous plate, and the utilization rate of the introduced gas is set to 30% in consideration of the cooling of the fuel cell, the gas permeability coefficient Is 5 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more, the amount of gas introduced and filled is sufficient, and the above-described advantages of the highly integrated structure can be obtained.

In the fuel cell stack, the smaller the differential pressure, the easier the system design, so it is desirable that the gas permeability coefficient is large (from the viewpoint of system design).
(6) In the invention of claim 6, the particles in the structure of the conductive plate-like body have an average particle diameter of 10 to 60 μm, and the porosity of the conductive plate-like body is 40 to 60%. It is characterized by that.

In the present invention, since the particles in the structure of the conductive plate-like body are coarse with an average particle diameter of 10 to 60 μm, there is an effect that the gas permeability coefficient (and hence the gas diffusion coefficient) is high.
Therefore, even when the particle size of the particles in the structure of the outer electrode is reduced to increase the electrode area and increase the power generation performance, it has excellent gas diffusion performance, and as a result, it has even better power generation performance. Has a remarkable effect.

  Furthermore, in the present invention, since the porosity is 40% or more, gas permeation is sufficient, and it is easy to obtain the performance of the fuel cell. Further, since the porosity is 60% or less, there is an advantage that the strength of the conductive plate-like body is high even if coarse particles are used as the raw material.

(7) In the invention according to claim 7, the particles in the structure of the conductive plate have an average particle size of 1 to 10 μm, and the porosity of the conductive plate is 50 to 90%. It is characterized by that.
In the present invention, since the porosity is as high as 50 to 90%, even if the particle diameter is 1 to 10 μm, the gas diffusion performance is excellent. In particular, by reducing the particle diameter, there is an advantage that high gas diffusion performance (due to high porosity) can be realized and sufficient strength can be obtained for the conductive plate-like body.

  That is, in the present invention, since the porosity is 50% or more, sufficient gas permeability is obtained, and since the porosity is 90% or less (the particle size may be small), the conductive plate shape Sufficient strength is obtained for the body.

  In the present invention, the difference between the particle size of the particles in the structure of the conductive plate and the particle size of the particles in the structure of the outer electrode is small. The particle size is smaller than that of the conductive plate), for example, by introducing a pore former into the raw material at the stage of producing the conductive plate, the configuration of the present invention can be realized.

(8) The invention according to claim 8 is characterized in that the conductive plate-like body has a maximum pore diameter in a range of 10 to 300 μm, and at least a part of each pore communicates. To do.
In the present invention, since the maximum pore diameter of the conductive plate-like body is 10 μm or more, the gas permeation performance is high, and since the maximum pore diameter is 300 μm or less, there is no need to increase the arrangement interval of each fuel cell part. The device can be made compact.

(9) In the ninth aspect of the invention, the relationship between the porosity and the particle diameter of the conductive plate-like body is (maximum pore diameter / 100) <average particle diameter <(maximum pore diameter / 4). Features.
In the present invention, since there is a relationship of (maximum pore diameter / 100) <average particle diameter, holes (pores) formed of a pore former or the like are easily connected to each other, and gas permeability is high. Further, since there is a relationship of average particle diameter <(maximum pore diameter / 4), the balance between the pore diameter and the particle diameter is good, and sufficient strength can be secured.

(10) The invention of claim 10 is characterized in that the particles in the structure of the outer electrode have an average particle diameter of 0.1 to 2 μm.
The present invention exemplifies a preferable average particle diameter of particles in the structure of the outer electrode, and within this range, the electrode area is wide and the electrode performance (and hence power generation performance) is high.

(11) The invention of claim 11 is characterized in that the outer electrode connects the solid electrolyte layer and a conductive plate-like body.
In the present invention, since the outer electrode connects the solid electrolyte layer and the conductive plate-like body, highly reliable electrical connection can be obtained, and the stack structure can be simplified.

(12) The invention of claim 12 is characterized in that the inner electrode is a support for the fuel cell section, and the thickness of the solid electrolyte layer is 30 μm or less.
The present invention exemplifies the configuration of the fuel cell unit. In the present invention, since the inner electrode is a support and a thin solid electrolyte layer of 30 μm or less is formed on the surface thereof, the resistance in the solid electrolyte layer can be reduced.

Incidentally, with cylindrical inner electrode adjacent arranged in parallel are connected together, the fuel cell unit having a solid electrolyte layer annular and is surrounded by forming the outer periphery of the connected inner electrode to the integrated The fuel cell unit is sandwiched between conductive plates made of porous conductive ceramics in the thickness direction, and an outer electrode of the fuel cell unit is interposed between the solid electrolyte layer and the conductive plate member It can be set as the structure provided with.
This arrangement, since each other inner electrodes are those which are connected together, high dimensional accuracy, also are easy to handle, has an advantage of high workability in manufacturing.

Moreover, it can be set as the structure by which the adjacent inner side electrode of the said fuel cell part was integrally connected through the connection part which has electroconductivity.
This configuration, the fuel cell unit to each other has been connected together, so that the inner electrode is (via the connecting part) integrally, there is an advantage that the structure for electrical connection can be simplified.

Furthermore , the wall surface part itself of the adjacent inner side electrode of the said fuel cell part can be set as the structure connected integrally.
This configuration has an advantage that the strength is high because the fuel cell portions are integrally connected and the wall surface of the inner electrode is integral.

( 13 ) A thirteenth aspect of the present invention is the fuel cell stack manufacturing method according to any one of the first to twelfth aspects of the present invention, wherein the fuel cell unit precursor is composed of the inner electrode and a solid electrolyte layer formed on the inner electrode. A first step of producing a sintered body of a battery body or a fuel cell part precursor, and a conductive plate precursor or a sintered body of a conductive plate precursor made of the porous conductive ceramic material And stacking the fuel cell part precursor with a conductive plate precursor, stacking the sintered body of the fuel cell part precursor with a conductive plate precursor, The fuel cell part precursor is stacked by sandwiching the sintered body of the conductive plate precursor, or the sintered body of the fuel cell part precursor is sandwiched by the sintered body of the conductive plate precursor. And a third step of stacking.

The present invention exemplifies a method for manufacturing a fuel cell stack, whereby the fuel cell stack can be easily manufactured.
In addition, here, each precursor has shown the molded object before baking, for example, the molded object after extrusion molding is mentioned (In addition, what was calcined is also included.). The order of the first step and the second step may be reversed.

( 14 ) According to the invention of claim 14 , between the fuel cell part precursor and the conductive plate precursor, between the sintered body of the fuel cell part precursor and the conductive plate precursor. Between the fuel cell part precursor and the sintered body of the conductive plate precursor, or between the fired body of the fuel cell part precursor and the fired body of the conductive plate precursor. Further, the material for the outer electrode is disposed and fired.

  Thereby, an outer electrode can be formed between the fuel cell part and the conductive plate (in a state where the fuel cell part and the conductive plate are in contact). This outer electrode exhibits a function of joining the fuel cell portion and the conductive plate-like body.

( 15 ) The invention of claim 15 is characterized in that the inner electrode precursor is produced by extrusion molding.
The present invention exemplifies a method of forming an inner electrode precursor (molded body before firing the inner electrode). Thereby, a large amount of inner electrode precursors can be easily manufactured. In this case, the inner electrode precursor is a molded body before firing.

( 16 ) The invention of claim 16 is characterized in that the conductive plate precursor is produced by extrusion.
The present invention exemplifies a method for forming a conductive plate precursor, whereby a large amount of conductive plate precursor can be easily produced. The conductive plate precursor in this case is a molded body before firing.

( 17 ) The invention of claim 17 is the method of manufacturing a fuel cell stack according to any one of claims 1 to 12 , wherein a raw material obtained by adding a spherical pore former to the porous conductive ceramics is used. Forming the conductive plate precursor and firing the conductive plate precursor to produce the conductive plate body which is a sintered body having pores.

  The present invention exemplifies a manufacturing method using a pore former. In the present invention, since a spherical pore former is used, it is easy to produce a conductive plate having a high porosity as in the case of the seventh aspect of the invention, and the control of the pore diameter is easy.

( 18 ) The invention of claim 18 is characterized in that a volume ratio of the spherical pore former to the raw material (porous conductive ceramic material + the entire raw material of the pore former) is 60 to 90% by volume. To do.

The present invention exemplifies a preferable ratio of the pore former. This ratio is an optimum ratio for realizing the invention of claim 7.
( 19 ) The invention according to claim 19 is characterized in that the firing temperature of the conductive plate precursor is 1300 ° C. or higher.

The present invention illustrates a preferred temperature range. If it is this temperature range, since especially high electroconductivity is obtained, it is suitable.
b) Hereinafter, each configuration of the fuel cell stack will be described in detail.

The inner electrode and the outer electrode are used as a fuel electrode in contact with the fuel gas and an air electrode in contact with the combustion-supporting gas serving as the oxygen source, respectively.
The “fuel electrode” is in contact with the fuel gas serving as the hydrogen source and functions as a negative electrode in the single cell.

As the fuel electrode, a cermet made of metal (particularly Ni) particles and ceramic particles can be employed.
In addition to Ni, Cu, Fe, Co, Ag, Pt, Pd, W, Mo, and alloys thereof can be used as the metal.

  Examples of the ceramic include zirconia, YSZ, ScSZ, SDC, GDC, alumina, silica, and titania. In particular, YSZ, ScSZ, SDC, and GDC are desirable. This is because they have oxygen ion conductivity and enhance the electrochemical activity of the fuel electrode.

The “air electrode” is in contact with a combustion-supporting gas that serves as an oxygen source and functions as a positive electrode in a single cell.
The material for the air electrode can be appropriately selected depending on the use conditions of the solid oxide fuel cell. As this material, for example, a metal, a metal oxide, a metal composite oxide, or the like can be used. Examples of the metal include metals such as Pt, Au, Ag, Pd, Ir, Ru, Ru, and alloys containing two or more metals.

Furthermore, examples of the metal oxide include oxides such as La, Sr, Ce, Co, Mn, and Fe (for example, La ₂ O ₃ , SrO, Ce ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , FeO). Etc.). Further, as the complex oxide, various complex oxides containing at least one of La, Pr, Sm, Sr, Ba, Co, Fe, Mn, etc. (for example, La _1-x Sr _x CoO ₃ series) Complex oxides, La _1-x Sr _x FeO ₃ complex oxides, La _1-x Sr _x Co _1-y Fe _y O ₃ complex oxides, La _1-x Sr _x MnO ₃ complex oxides, Pr _1-x Ba _x CoO ₃ composite oxide, Sm _1-x Sr _x CoO ₃ composite oxide, and the like.

  -Examples of the "solid electrolyte layer" include YSZ (yttria stabilized zirconia), ScSZ (scandia stabilized zirconia), SDC (ceria doped with samaria), GDC (ceria doped with gadria), perovskite oxide, etc. It is done. These may be a single film or a multilayer film in which two or more kinds of compositions have a laminated structure. Examples of the multilayer film include a YSZ + SDC film and a YSZ + GDC film.

  The solid electrolyte layer has ionic conductivity capable of moving at least a part of one of the fuel gas introduced into the fuel electrode or the combustion-supporting gas introduced into the air electrode during operation of the fuel cell as ions. . Although what kind of ion can be conducted is not particularly limited, examples of the ion include oxygen ion and hydrogen ion.

-As a constituent material of the porous conductive plate-like body, any element of Ag, La, Sr, Mn, Co, Fe, Sm, Ce, Pr, Nd, Ca, Ba, Ni, Mg, Ti, Alternatively, an oxide containing one or more of these elements can be employed. For example, La _1-x Sr _x CrO ₃ -based material (the outer electrode can be either a fuel electrode or an air electrode), La _1-x Sr _x Co _1-y Fe _y O ₃ -based material (the outer electrode is an air electrode) Only possible), La _1-x Sr _x MnO ₃ based material (only when the outside is an air electrode), Sm _1-x Sr _x CoO ₃ based material (only when the outside is an air electrode), etc. Material can be adopted.

  ・ "Fuel gas" refers to hydrogen, hydrocarbons that serve as hydrogen sources, mixed gases of hydrogen and hydrocarbons, fuel gases that have been humidified by passing these gases through water at a predetermined temperature, and water vapor mixed with these gases. Fuel gas and the like.

  The hydrocarbon is not particularly limited, and examples thereof include natural gas, naphtha, and coal gasification gas. Further, the main components are saturated hydrocarbons having 1 to 10, preferably 1 to 7, more preferably 1 to 4 carbon atoms such as methane, ethane, propane, butane and pentane, and unsaturated hydrocarbons such as ethylene and propylene. Those having a saturated hydrocarbon as a main component are more preferable. These fuel gas may use only 1 type and can also use 2 or more types together. Moreover, you may contain inert gas, such as nitrogen and argon.

  -“Flame-supporting gas” includes a mixed gas of oxygen and other gases. The mixed gas may contain 80% by volume or less of an inert gas such as nitrogen and argon. Among these combustion-supporting gases, air (containing about 80% by volume of nitrogen) is preferable because it is safe and inexpensive.

c) will be described below with the reactor stack and a manufacturing how applicable the structure of the present invention.
<1> Reactor layer shape in which a plurality of reactor sections each having a cylindrical inner porous ceramic body and a solid treatment layer that can permeate specific ions, atoms, or molecules formed on the outer peripheral surface thereof are arranged in parallel And the reactor layered portion is sandwiched by a plate-like body made of porous ceramics in the thickness direction, and an outer porous ceramic body is provided between the solid treatment layer and the plate-like body. reactor stack to be.

Since this reactor stack has a structure in which a reactor layered portion in which a plurality of cylindrical inner porous ceramic bodies are arranged in parallel (for example, in parallel) is sandwiched between plate-like bodies, the inner porous ceramic bodies are arranged together. And the positioning accuracy of the inner porous ceramic body can be increased. That is, there is an advantage that the positioning accuracy of the reactor is higher than the conventional technique in which the reactor is immersed in the slurry.

  Here, the reactor section includes an inner porous ceramic body (for example, an inner electrode having a catalytic function) and a solid electrolyte layer, and an outer porous ceramic body (for example, an outer electrode). Is a reactor (cell).

  Further, when conductive materials are used as the inner porous ceramic body and the outer porous ceramic body, the porous conductive ceramic used in the fuel cell stack is used as the plate-like body. (The same applies to the following).

<2> The particles in the structure of the outer porous ceramic body have an average particle diameter of 0.1 to 2 μm.
This exemplifies the preferable average particle diameter of the particles in the structure of the outer porous ceramic body, and within this range, it has high gas reaction and separation performance.

<3> Reactor layer shape in which a plurality of reactor parts having a cylindrical inner porous ceramic body and a solid treatment layer that is permeable to specific ions, atoms, or molecules formed on the outer peripheral surface thereof are arranged in parallel comprising a part, the reactor stack, wherein the reactor layer portion is sandwiched by the plate-like member made of a porous ceramic in the thickness direction thereof.

Since this reactor stack has a structure in which a reactor layered portion in which a plurality of cylindrical inner porous ceramic bodies are arranged in parallel (for example, in parallel) is sandwiched between plate-like bodies, the inner porous ceramic bodies are arranged together. And the positioning accuracy of the inner porous ceramic body can be increased.

Note that this is a reactor stack that does not require an outer porous ceramic body.
<4> The plate-like body includes a plurality of parallel grooves into which the reactor portion is fitted on the surface thereof, and the reactor portion is fitted into the groove and fixed between the plate-like bodies. It is characterized by.

In this configuration, the reactor part is fitted into each of a plurality of parallel grooves on the surface of the plate-like body, and the plurality of reactor parts are sandwiched between the plate-like bodies from both sides, so that the reactor part can be firmly fixed.

<5> The plate-like body has a gas permeability coefficient of 5 × 10 ⁻⁵ cm ² · sec ⁻¹ · Pa ⁻¹ or more.
This plate-like body has a high gas permeability coefficient, and can realize a reactor stack having a high integration density and a structure resistant to thermal cycling.

  That is, as in the invention of claim 3, when the plate-like body has this gas permeability coefficient (particularly when a differential pressure of 0.2 MPa or more is set on the gas inlet side and outlet side of the plate-like body). The amount of gas to be introduced is ensured, and the advantages of a highly integrated structure (advantages of being compact and capable of realizing a sufficient reaction even at low temperatures) are obtained.

<6> The plate-like body has a gas permeability coefficient of 1 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more.
As in the invention of claim 4, when the plate-like body has this gas permeability coefficient (especially when a differential pressure of 0.1 MPa or more is set between the gas inlet side and the outlet side of the plate-like body), The amount of gas to be produced is ensured, and the advantages of a highly integrated structure can be obtained.

<7> The plate-like body has a gas permeability coefficient of 5 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more.
As in the invention of claim 5, when the plate-like body has this gas permeability coefficient (especially when a differential pressure of 0.02 MPa or more is set between the gas inlet side and the outlet side of the plate-like body), The amount of gas to be produced is ensured, and the advantages of a highly integrated structure can be obtained.

In the reactor stack, the smaller the differential pressure, the easier the system design, so it is desirable that the gas permeability coefficient be large (from the viewpoint of system design).
<8> The particles in the structure of the plate-like body have an average particle diameter of 10 to 60 μm, and the porosity of the plate-like body is 40 to 60%.

Similar to the sixth aspect of the invention, since the particles in the plate-like structure are coarse with an average particle diameter of 10 to 60 μm, there is an effect that the gas permeability coefficient (and hence the gas diffusion coefficient) is high.
Therefore, even when the particle size of the particles in the structure of the outer porous ceramic body is reduced to increase the surface area and increase the reaction performance, it has excellent gas diffusion performance, resulting in even better reaction performance. There is a remarkable effect of having.

Further, in this configuration , since the porosity is 40% or more, gas permeation is sufficient, and it is easy to obtain the performance of the reactor. Further, since the porosity is 60% or less, there is an advantage that the strength of the plate-like body is high even if coarse particles are used as the raw material.

<9> The particles in the structure of the plate-like body have an average particle diameter of 1 to 10 μm, and the porosity of the plate-like body is 50 to 90%.
In this configuration , the porosity is as high as 50 to 90% as in the case of the seventh aspect of the invention. Therefore, even if the particle diameter is 1 to 10 μm, the gas diffusion performance is excellent. In particular, by reducing the particle diameter, there is an advantage that high gas diffusion performance (due to high porosity) can be realized and sufficient strength can be obtained for the plate-like body.

Further, this configuration can be realized, for example, by introducing a pore former into the raw material at the stage of producing the plate-like body.
<10> The plate-like body is characterized in that the pores have a maximum pore diameter in the range of 10 to 300 μm, and at least a part of each pore communicates.

In this configuration, similarly to the invention of claim 8, since the maximum pore diameter of the plate-like pores is 10 μm or more, the gas permeation performance is high, and the maximum pore diameter is 300 μm or less. There is no need to increase the arrangement interval, and the apparatus can be made compact.

<11> The relationship between the porosity of the plate-like body and the particle size is (maximum pore size / 100) <average particle size <(maximum pore size / 4).
In this configuration, as in the invention of claim 9, since there is a relationship of (maximum pore diameter / 100) <average particle diameter, the holes (pores) formed by the pore former and the like are easily connected to each other, High gas permeability. Further, since there is a relationship of average particle diameter <(maximum pore diameter / 4), the balance between the pore diameter and the particle diameter is good, and sufficient strength can be secured.

<12> the reactor layer portion, the inner porous ceramic body adjacent to each other and having a structure that is integrally connected.
In this configuration, since the inner porous ceramic bodies are integrally connected, there are advantages that the dimensional accuracy is high, the handling is easy, and the workability at the time of manufacture is high.

<13> The next case earthenware pots in side the porous ceramic body, characterized in that connected together through a connecting portion.
This is an example of a structure in which the inner porous ceramic bodies are integrally connected, and the inner porous ceramic body is integral (via the connecting portion), so that there is an advantage that the structure can be simplified.

When the inner porous ceramic body is an inner electrode, the connecting portion has conductivity.
<14> wall portion itself of the adjacent coupling power sale in side the porous ceramic body is characterized in that it is integrally connected.

This is an example of a structure in which the inner porous ceramic bodies are integrally connected, and since the wall surface of the inner porous ceramic body is integral, there is an advantage that the strength is high.
<15> In the reactor stack manufacturing method described above, a reactor part precursor or a reactor part precursor comprising the inner porous ceramic body and a solid treatment layer capable of transmitting specific ions, atoms, or molecules formed on the surface thereof A first step of producing a sintered body of the above, a second step of producing a plate-like body precursor made of the porous ceramic material or a sintered body of the plate-like body precursor, and the reactor part precursor Stacked by sandwiching a plate-shaped precursor, stacked by sandwiching the sintered body of the reactor part precursor with the plate-shaped precursor, and sintering the reactor part precursor with the sintered body of the plate-shaped body precursor And a third step of stacking and stacking the sintered body of the reactor part precursor with the sintered body of the plate-like body precursor.

This configuration exemplifies a method for manufacturing a reactor stack, and thus the reactor stack can be easily manufactured.
In addition, here, each precursor has shown the molded object before baking, for example, the molded object after extrusion molding is mentioned (In addition, what was calcined is also included.). The order of the first step and the second step may be reversed.

<16> Between the reactor part precursor and the plate precursor, between the sintered body of the reactor part precursor and the plate precursor, the reactor part precursor and the plate precursor. The outer porous ceramic body material is disposed and fired between the sintered body of the body or between the sintered body of the reactor part precursor and the sintered body of the plate-like body precursor. It is characterized by.

  Thereby, an outer porous ceramic body can be formed between the reactor part and the plate-like body (in a state where the reactor part and the plate-like body are in contact). The outer porous ceramic body exhibits a function of joining the reactor portion and the plate-like body.

<17> An inner porous ceramic body precursor is produced by extrusion molding.
This configuration exemplifies a method for forming the inner porous ceramic body precursor. Thereby, a large amount of inner porous ceramic body precursors can be easily manufactured. In this case, the inner porous ceramic body precursor is a molded body before firing.

<18> The plate-like body precursor is formed by extrusion.
This configuration exemplifies a method for forming a plate-like precursor, whereby a large amount of plate-like precursor can be easily produced. In this case, the plate-like precursor is a molded body before firing.

<19> In the reactor stack manufacturing method described above, by forming a plate-like precursor using a raw material obtained by adding a spherical pore former to the porous ceramic, and firing the plate-like precursor, The plate-like body, which is a sintered body having pores, is manufactured.

Similar to the invention of the seventeenth aspect , this configuration exemplifies a manufacturing method using a pore former. Here, since the spherical pore former is used, it is easy to produce a conductive plate having a high porosity, and the pore diameter can be easily controlled.

<20> The volume ratio of the spherical pore former to the raw material is 60 to 90% by volume.
Similar to the eighteenth aspect of the present invention, this configuration illustrates a preferable proportion of the pore former.

<21> The firing temperature of the plate-like body precursor is 1300 ° C. or higher.
Similar to the invention of the nineteenth aspect , this configuration exemplifies a preferable temperature range. Within this temperature range, for example, when the plate-like body has conductivity, it is preferable because high conductivity can be obtained.

Since each configuration of the reactor stack is substantially the same as each configuration of the fuel cell stack, a brief description will be given.
-As the "solid treatment layer", the same material as the solid electrolyte used in the fuel cell stack can be used, but in addition, a thin film (solid treatment layer) that can transmit specific ions, atoms, or molecules can be used. Various materials can be used. For example, a material constituting a palladium metal film or a palladium / silver alloy film can be employed.

The specific ion, atom, or molecule includes an ion, atom, or molecule such as hydrogen or oxygen.
-Reactor materials differ depending on the type of reactor and cannot be summarized easily. For example, as a technology for purifying NOx, the reactor has the same material structure as that of the fuel cell and is used as a reactor for purifying NOx. It is possible to operate.

Further, for example, in the case of hydrogen production technology, a specific ion-permeable thin film is made of palladium metal having hydrogen permeability or at least one element of palladium and Pt, Au, Ag, Cu, Ni, etc. An alloy and an oxide having a BaCeO ₃ -based perovskite structure are conceivable.

  -For the inner porous ceramics and the outer porous ceramics, either one having no catalytic ability or one having catalytic ability can be installed. The material having catalytic ability may be any material capable of decomposing hydrocarbon compounds such as natural gas, naphtha, coal gasification gas, methane, ethane, propane, butane, pentane, Ni, Cu, Fe, Co, Ag. , Pt, Pd, W, Mo and alloys thereof can be employed. In addition, examples of materials that do not have catalytic ability include alumina, magnesia, zirconia, titania, and mixtures and compounds thereof.

  Here, when using porous ceramics that do not have catalytic ability, only a palladium-based metal thin film can be obtained by introducing a mixed gas such as carbon monoxide and hydrogen after treatment with a simple reformer into the reactor. It is effective as a reactor for extracting pure hydrogen.

  As the constituent material of the porous plate-like body, when conductivity is required, Ag, La, Sr, Mn, Co, Fe, Sm, Ce, Pr, Nd, Ca, Ba, Ni, Mg, Ti Any of these elements or an oxide containing one or more of these elements can be used. The porous plate-like body does not need to be conductive except when an electrode is used, and various porous ceramics such as alumina can be used. In addition, as the porous plate-like body, materials having different particle diameters from the materials mentioned as the porous ceramics can be employed.

  Hereinafter, examples (examples) of the embodiments of the present invention will be described.

Here, a solid oxide fuel cell (hereinafter also simply referred to as a fuel cell) stack and a manufacturing method thereof will be described.
a) First, the overall configuration of the fuel cell stack of this embodiment will be described.

  As shown in FIG. 1, in the fuel cell stack 1 of this embodiment, a large number of cylindrical fuel cell portions 3 are arranged in parallel in the axial direction, and the fuel cell layered portions 5 are arranged in a line in the left-right direction. The fuel cell layered portion 5 is formed in a plurality of layers parallel to the vertical direction of the figure.

  Further, the fuel cell layered portion 5 is sandwiched from above and below by a conductive plate (current collector) 9 through an outer electrode (air electrode) 7. That is, the fuel cell layered portion 5 is in a state of being stacked via the outer electrode 7 and the conductive plate-like body 9, and electricity can be taken out from the vertical direction in the figure.

  Specifically, as shown in FIG. 2, a solid electrolyte layer 13 having oxygen ion conductivity is formed on the outer peripheral surface of a cylindrical inner electrode (fuel electrode) 11 in contact with a fuel gas (for example, hydrogen) to form a fuel cell unit. 3 is formed, and an outer electrode 7 in contact with a combustion-supporting gas (for example, oxygen in the air) is formed so as to be in contact with the solid electrolyte layer 13. This outer electrode 7 is in contact with the outer peripheral surface of another similar fuel cell unit 3 (and hence each solid electrolyte layer 13) arranged in a horizontal row in the same figure, and is shared with other fuel cell units 3 It is. When the outer electrode 7 is formed only in the groove 15 (see FIG. 4), the outer electrode 7 is not shared with the other fuel cell units 3.

The outer electrode 7 is disposed between each fuel cell unit 3 and the conductive plate 9 to ensure electrical connection and connect each fuel cell unit 3 to the conductive plate 9 ( Joining).
Therefore, a fuel cell (cell) 8 is constituted by the inner electrode 11, the solid electrolyte layer 13 and the outer electrode 7, and the fuel cell is composed of the inner electrode 11 and the solid electrolyte layer 13 separated into a plurality of locations (four locations in the figure). The fuel cell layered portion 5 is composed of a layered outer electrode 7 that is continuous with the portion 3. The number of fuel cell units 3 is shown differently in each figure for easy explanation, but of course, the number is actually the same (for example, 10 vertical x 10 horizontal x 100 in total). .
Among these, the fuel cell unit 3 is a cylinder having an outer diameter of 3 mm or less, as shown in FIG. 3. Except for both ends of the cylindrical outer surface of the inner electrode 11 having a thickness of, for example, 50 to 400 μm. For example, it is covered with a solid electrolyte layer 13 having a thickness of 2 to 30 μm.

  In addition, as shown in FIG. 4, the conductive plate-like body 9 is formed by forming grooves 15 having a semicircular cross-sectional shape into which the fuel cell unit 3 is fitted in parallel on both upper and lower sides. The conductive plate 9 at the upper and lower ends of the fuel cell stack 1 has grooves 15 formed only on one surface side.

  In particular, in this embodiment, the average particle diameter of the structure of the structure (sintered body) of the outer electrode 7 is 0.1 to 2 μm (desirably 0.1 to 1 μm, more desirably 0.3 to 0.00). The average particle diameter of the particles of the structure (sintered body) of the outer electrode 7 is 10 to 60 μm (desirably 20 to 50 μm, more desirably 30 to 8 μm). 50 μm), and is composed of coarser particles than the outer electrode 11.

  In the fuel cell stack 1 described above, power can be generated by flowing air in the X direction in FIG. 1 and flowing fuel gas in the Y direction via the conductive plate-like body 9. For example, the electricity collected on the inner electrode (fuel electrode) 11 side is taken out from both ends of the fuel cell unit 3, and the current collection on the outer electrode (air electrode) 7 side is taken out from the upper and lower planes of FIG. be able to.

b) Next, a method for manufacturing the fuel cell stack 1 will be described.
For example, NiO: 50% by weight with an average particle size of 0.1 to 2 μm (preferably 0.1 to 1 μm, more preferably 0.3 to 0.8 μm), an average particle size of 0.1 to 2 μm (preferably 0.1 Gd _0.2 Ce _0.8 O _1.9 : 39% by weight and cellulose binder: 7% by weight of 1 wt. The external weight% was added and mixed for another 30 minutes.

After passing this mixture through three rolls, the prepared substrate was left overnight.
Thereafter, as shown in FIG. 5, the substrate was subjected to extrusion molding using a uniaxial hydraulic cylinder type extrusion molding machine 21.

Further, a butyral binder: 4 wt.% And methyl ethyl ketone: 100 wt.% Are added to Gd _0.2 Ce _0.8 O _{1.9 and} mixed for 24 hours to form a slurry 23. The fuel formed in the slurry 23 by the extrusion molding. The polar molded body (that is, the inner electrode precursor) 25 was immersed. As a result, a solid electrolyte coating 27 was formed on the surface of the fuel electrode molded body 25.

Thereafter, the fuel electrode molded body 25 (that is, the fuel cell part precursor) on which the coating film 27 was formed was simultaneously fired in the atmosphere at 1400 ° C. for 1 hour to produce the fuel cell part 3.
On the other hand, 93% by weight of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ (LSCF powder) having an average particle size of 10 to 60 μm (preferably 20 to 50 μm, more preferably 30 to 50 μm) and 7% by weight of a cellulose binder are dry-treated. After mixing with a mixer for 1 hour, water was added in an external weight of 14% by weight with respect to the powder and mixed for another 30 minutes.

  In addition, as a method of obtaining coarse particles such as the above LSCF powder, after calcination of the LSCF powder (about 0.1 to 2 μm), the particle size is adjusted, or the LSCF powder (0.1 to 2 μm) is used. Grade) is formed into spherical particles using a rolling granulator or spray dry, and used after calcination.

Then, after passing the mixture through three rolls, the prepared substrate was left overnight.
Then, the said base material was extrusion-molded with the screw-type extrusion molding machine (not shown).

  Next, this molded body (that is, the conductive plate precursor) was fired in the atmosphere at 1200 to 1500 ° C. for 1 to 3 hours to produce a conductive plate 9. Thereby, the electroconductive plate-like body 9 with a large average particle diameter is obtained.

  Thereafter, the electrode material of the outer electrode 7 was applied to the surface of the conductive plate 9 (the surface on the side of the groove 15 sandwiching the fuel cell unit 3). Specifically, with respect to LSCF powder having an average particle size of 0.1 to 2 μm (preferably 0.1 to 1 μm, more preferably 0.3 to 0.8 μm), ethyl cellulose as a binder: 5% by weight, dispersed Agent: 1 wt%, butyl carbitol: 13 wt% was added, and paste 10 mixed by three rolls was applied by screen printing so that the grooves 15 were filled.

Then, the fuel cell unit 3 was installed on the groove 15 of the conductive plate 9 and sandwiched and laminated by another conductive plate 9.
Thereafter, it is baked at 1000 ° C. for 2 hours in the atmosphere to form the fuel cell stack 1 of this example. In addition, the outer electrode 7 whose average particle diameter is smaller than the conductive plate 9 is obtained by the final firing.

  The fuel cell stack 1 manufactured as described above has a small surface area of 0.1 to 2 [mu] m and a large surface area of the electrode because the tissue particles of the outer electrode 7 are as small as 0.1 to 2 [mu] m. Therefore, electric resistance is small and power generation performance is excellent.

  Moreover, since the particle | grains of the structure | tissue of the electroconductive plate-shaped body 9 are as large as 10-60 micrometers and a particle | grain are coarse, air tends to pass through the inside of the electroconductive plate-shaped body 9. FIG. Therefore, since the ability of gas diffusion is high, there is an advantage that the power generation performance is improved from that point.

(Experimental example 1)
Next, an experimental example in which the characteristics of the conductive plate used in the fuel cell stack described above, that is, the gas permeability coefficient, the electrical conductivity, and the porosity are measured will be described.

  In this experimental example, the same material as the conductive plate-like body of Example 1 (material without a pore-forming material) was used, and a sample was manufactured in the same manufacturing process. As shown in Table 1 below, the firing temperature was 1100 to 1400 ° C.

<Measurement of gas permeability coefficient>
The shape of the sample used for the measurement of the gas permeability coefficient is a disk shape with a diameter of 30 mm and a thickness of 1 mm.

A sample 37 is sandwiched between upper and lower packings 33 and 35 in the measurement jig 31 shown in FIG. 6, and the upper jig 39 and the upper jig 41 are tightened and sealed with screws (not shown).
A round hole with a diameter of 8 mm was opened at the center of the packings 33 and 35. Gas pressure was applied from below and the amount of gas coming out from above was measured with a soap film flow meter.

Moreover, the inlet side gas pressure was adjusted in the range which can measure an exact flow rate with a soap film flowmeter in the range of 0.05-0.2 MPa, and measured. The results are shown in Table 1 below.
In addition, the gas permeability coefficient C was calculated | required by following formula (1). Here, F is a gas flow rate (permeate gas flow rate: mlmin ⁻¹ ), t is a sample thickness (cm), 60 is a time (second), A is a gas permeation area (sample area: cm ² ), and P is from one side. It is the added gas pressure (gas pressure difference at the inlet and outlet: Pa).

Gas permeability coefficient C = Ft / 60AP (1)

<Measurement of electrical conductivity>
The electrical conductivity was a sample for evaluation using a columnar sample having a length of 3 mm × width of 4 mm × length of 40 mm, and an electrode attached as defined in JIS R1661. The measurement was performed using a DC power source and a voltmeter in an atmosphere at 600 ° C. in the air. Specifically, by applying a direct current from both ends of the sample and recording the voltage at that time, current I (A), voltage E (V), sample cross-sectional area A (cm ² ), distance between voltage terminals From L (cm), the electrical conductivity k (Scm ⁻¹ ) was determined using the following formula (2). The results are also shown in Table 1 below.

Electrical conductivity k = IL / EA (2)

<Measurement of average particle diameter>
The average particle diameter was obtained by observing with a scanning electron microscope in a visual field where 100 or more particles constituting the conductive plate-like body could be observed, and averaging them. The results are also shown in Table 1 below. In Table 1 below, the average particle diameter after firing is shown.

<Measurement of porosity>
With respect to the obtained sample, dry weight W1, vacuum weight in water for 15 minutes or more, hydrous weight W2 containing water, and wet water weight W3 of the sample were measured. P was determined. Here, the density of water is ρw, and the density of the constituent material is ρc. The results are also shown in Table 1 below.

Porosity P = {1− (W1 × ρw) / ((W2−W3) × ρc)} × 100 (3)

The handling property in Table 1 (and Table 2 below) refers to the state of the sample when picked up by hand. The case where it would collapse if it was not raised was marked as x.

  As is clear from Table 1, in Samples Nos. 2 to 5, the average particle diameter is 10 μm or more and 60 μm or less, so the gas permeability coefficient, electrical conductivity, and porosity are high, and the current collection of the porous body of the fuel cell It turns out that it is suitable as a body.

On the other hand, sample No. 1 has an average particle size as small as 2.1 μm and a porosity as low as 38%, so it is difficult to obtain a gas permeation amount necessary for power generation.
In Samples Nos. 6 and 7, the average particle diameter is as coarse as 70 μm, and it is difficult to sinter ceramics and handling is difficult. In addition, since measurement of a gas permeability coefficient and electrical conductivity is difficult if a support is not attached, the measured value is not described here.

(Experimental example 2)
Next, an experimental example when a conductive plate-like body is manufactured using a pore former will be described.
<Preparation of sample>
La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ -δ (LSCF powder) having an average particle size of 0.1 to 11 μm and 50 to 95% by volume of spherical polymethyl methacrylate bead powder having an average particle size of 5 to 350 μm are mixed. In addition, 7% by weight of a cellulosic binder was added to the LSCF powder, and after mixing for 1 hour with a dry mixer, 14% by weight of water was added to the LSCF powder and mixed for another 30 minutes.

Then, after passing the mixture through three rolls, the prepared substrate was left overnight.
Thereafter, the substrate was subjected to extrusion molding with a screw-type extrusion molding machine.
Next, this molded body (that is, a conductive plate precursor) was fired in the atmosphere at 1200 to 1400 ° C. for 1 hour to produce a conductive plate sample.

And the following measurements were performed using this sample.
<Measurement of gas permeability coefficient>
The shape of the sample used for measurement of the gas permeability coefficient is a disk shape having a diameter of 20 mm and a thickness of 2 mm.

Using the same apparatus as that shown in FIG. 6, the gas pressure was applied from above and the amount of gas coming out from below was measured with a soap film flow meter.
Others were the same as in Experimental Example 1, and the gas permeation coefficient was determined by the equation (1). The results are shown in Table 2 below.

<Measurement of electrical conductivity>
The electrical conductivity was determined by the above formula (2) in the same manner as in Experimental Example 1. The results are also shown in Table 2 below.

<Measurement of average particle diameter>
The particle diameter of the raw material powder before sintering was determined by an average particle diameter using a laser diffraction particle size distribution measuring device. Moreover, the average particle diameter after sintering of each sample was determined in the same manner as in Experimental Example 1. The results are also shown in Table 2 below.

<Measurement of maximum pore diameter>
The maximum pore diameter was determined by confirming the largest pore in a field of view where 20 or more pores formed of a pore-forming material could be observed with a scanning electron microscope, and increasing the magnification of the microscope. The results are also shown in Table 2 below.

<Measurement of porosity>
In the same manner as in Experimental Example 1, the porosity was determined by the above formula (3). The results are also shown in Table 2 below.

As apparent from Table 2, sample Nos. 1 to 11 satisfy the conditions of claims 7 to 9, and the gas permeation coefficients of these samples ensure the amount of gas permeation necessary for obtaining power generation performance. It is suitable because it is made.

  Sample No. 12 is a sample having an average particle diameter (after sintering) of less than 1 μm, but this gas permeability coefficient has only a low value even though the porosity is 58%. When the structure of the sample was observed with an electron microscope, the pores were not in communication with each other. Therefore, it was difficult to ventilate the conductive plate-like body composed of particles having a fine particle size. I understood that.

  Sample No. 13 had a particle size of 11 μm or more and a high porosity of 71%, but this sample was very fragile and difficult to handle. This is probably because the electroconductive plate-like body was produced from coarse particles, so that sintering did not proceed so much and many pores were present, and therefore it became brittle.

Sample No. 14 has a porosity of less than 50%, and it can be seen from the gas permeability coefficient that a sufficient gas permeation amount cannot be secured to obtain power generation performance.
Sample No. 15 is a fragile sample having a porosity exceeding 90% but difficult to handle.

  Sample No. 16 is a sample having a maximum pore diameter exceeding 300 μm. This sample has sufficient gas permeation performance to obtain power generation performance. For example, when arranging cylindrical fuel cells, the cylindrical fuel cells must be arranged at intervals of 300 μm or more, and the size is large. turn into.

  In sample No. 17, the pore diameter was 10 μm or less, but sufficient gas permeation performance could not be obtained even though the porosity was 61%. It was found by electron microscope observation that when the pore diameter is small, communication holes are hardly formed.

  Sample No. 18 has a particle size of 1/100 or less of the maximum pore size, but a sufficient gas permeability coefficient is not obtained despite the porosity of 68%. It was confirmed by structure observation with an electron microscope that the particle diameter was too small for the pores and the pores were not in communication with each other.

  In sample No. 19, the particle size is 10 μm with respect to the maximum pore size of 17 μm. At this time, only a sample that was difficult to handle fragilely was obtained because the pore size was too small for the size of the particles.

When these samples are confirmed, in order to obtain a sample having a porosity of 50 to 90%, it is understood that the amount of pore former added is 60 to 90%.
Furthermore, from Sample Nos. 7 to 9, when the firing temperature was changed, the change in gas permeability coefficient was slight, but the electrical conductivity was greatly changed. From these results, it was found that a sample having better electrical characteristics can be obtained at a higher firing temperature.

Next, the second embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
a) First, the configuration of the fuel cell stack of this embodiment will be described.
The fuel cell stack 51 of this embodiment (see FIG. 9) is a stack (laminate) that is substantially the same as that of the first embodiment.

  In particular, in this embodiment, the fuel cell portion is not separated as in the first embodiment, but the fuel cell portion 53 has an integral structure as shown in FIG. The solid electrolyte layer 55 is integrally formed in a band shape.

  Specifically, as shown in FIG. 8, cylindrical inner electrodes (fuel electrodes) 57 are integrally formed in a horizontal row by a connecting portion 59 made of the same material. A solid electrolyte layer 55 is formed in an annular shape so as to surround the outer periphery of the integral inner electrode 57.

b) Next, a method for manufacturing the fuel cell stack 51 of this embodiment will be described.
The manufacturing method of the fuel cell stack of this embodiment is basically the same as that of the first embodiment, and will be described briefly.

As shown in FIG. 9, the substrate produced in the same manner as in Example 1 was extruded using a uniaxial hydraulic cylinder type extrusion molding machine 61.
Similarly, the fuel electrode molded body 67 formed by the extrusion molding (cylinder connected in the lateral direction) was immersed in the slurry 65 for forming the solid electrolyte coating 63. As a result, a solid electrolyte film 63 was formed on the surface of the fuel electrode molded body 67.

Thereafter, the fuel electrode molded body 67 on which the coating 63 was formed was fired in the same manner to manufacture the fuel cell portion 69.
On the other hand, in the same manner as in Example 1, the substrate for the conductive plate-like body 71 was subjected to extrusion molding with a screw-type extrusion molding machine (not shown).

Next, the conductive plate-shaped body was fired in the same manner to produce a conductive plate-shaped body 71.
Thereafter, a similar paste 73 was applied to the surface of the conductive plate-like body 71 so that the grooves 75 were filled by screen printing.

Then, on the conductive plate 71, the outer peripheral convex portion (cylindrical convex portion) of the fuel cell unit 69 was installed in the groove 75, and the other conductive plate 71 was sandwiched and laminated.
Thereafter, the fuel cell stack 51 of the present embodiment is formed by firing in the same manner.

  Also in this embodiment, the same effects as those of the first embodiment can be obtained, and the fuel cell unit 69 is not separated but integrated, and thus there are advantages that it is easy to handle.

Next, the third embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
Unlike the fuel cell stacks of the first and second embodiments, the present embodiment relates to a solid electrolyte reactor (hereinafter also simply referred to as a reactor (reactor)) stack. It is almost the same as the battery stack, and its material and application are mainly different.

  The reactor stack (ceramics reactor) in the present embodiment is a solid electrolyte having a characteristic of passing a specific element and promoting a reaction using a permeated gas, or a specific element from a mixture of a plurality of gas species. Or for the purpose of reaction.

  Regarding this reactor stack, the reactor stack may be energized to forcibly react and separate. Moreover, even if it does not supply with electricity, what can react and isolate | separate by the catalytic ability and ion selectivity which material itself has may be sufficient.

In any of these, since it is important that the gas diffuses efficiently inside the reactor, the reaction or separation method, the type of reaction, or the type of separation is not selected.
The reactor stack can be applied to NOx purification technology and hydrogen production technology as described below.

  a) For example, when exhaust gas from a diesel engine vehicle is introduced into an inner electrode (for example, a fuel electrode similar to a fuel cell) of a reactor stack and forcedly energized, NOx contained in the exhaust gas releases oxygen atoms on the electrode. Can be purified.

  In this case, the material structure of the reactor stack may be Ni, Pt, or the like as the NOx introduction side electrode, and any solid electrolyte having oxygen ion conductivity may be used. A zirconia electrolyte, a ceria electrolyte, Any lanthanum galade electrolyte may be used. The counter electrode may be any electrode that can oxygenate oxygen ions. In addition to Pt and Ag, combinations such as an air electrode (for example, an outer electrode) used in the fuel cell are conceivable.

  Therefore, in this embodiment, when the reactor stack similar to that in FIG. 1 is used and exhaust gas is supplied in the X direction of FIG. 1, for example, the gas containing NOx is decomposed into nitrogen and oxygen by the inner electrode of the reactor. At the gas outlet in the direction, the amount of NOx decreases and a gas containing decomposed nitrogen can be taken out.

  b) For example, when a catalyst capable of hydrogenating a gas such as methane at a high temperature (for example, the inner electrode) is used and a membrane having hydrogen ion conductivity is used for the solid electrolyte layer (membrane), the methane side and the hydrogen extraction side It can be used as a reactor stack that can extract hydrogen by applying a gas differential pressure.

In this reactor stack, metals such as Ni, Cu, and Pt can be considered as catalysts for reforming methane and the like (and hence electrodes), and a thin film of a solid electrolyte having hydrogen permeability includes a palladium metal film and An alloy of palladium and at least one element of Pt, Au, Ag, Cu, Ni, or the like, or an electrolyte having a BaCeO ₃ perovskite structure can be employed. Furthermore, any one of alumina, zirconia, magnesia, titania, a mixture thereof, and a compound can be adopted as the porous plate-like body.

In this case, since hydrogen can be taken out by differential pressure, there is no counter electrode, and any material can be used as long as the reactor stack can be maintained in a gas-permeable structure.
The structural relationship between the reactor stack and the fuel cell stack 1 of Example 1 is shown in FIG. 2. The fuel cell portion 3, the fuel cell layer portion 5, the outer electrode 7, and the conductive plate 9 , The inner electrode 11, the solid electrolyte layer 13, and the fuel cell 8 are respectively a reactor part, a reactor layer part, an outer electrode (or outer porous ceramic body), a porous plate-like body, and an inner electrode (or inner porous part). It corresponds to a ceramic body), a solid electrolyte layer (or solid treatment layer), and a reactor cell.

Needless to say, the present invention is not limited to the above-described embodiments and the like, and can be implemented in various modes without departing from the scope of the present invention.
(1) As shown in FIG. 10, for example, a configuration in which the walls (wall surface portions) of the plurality of inner electrodes 81 are integrated to form a plate-like fuel cell portion 83 (or a reactor portion) can be employed.

(2) The inner electrode and the outer electrode may be reversed. For example, the gas flow path may be switched so that the inner electrode is an air electrode and the outer electrode is a fuel electrode.
(3) Furthermore, as a method for arranging a large number of cylindrical fuel cell units, a method in which the number of arrangements in the vertical and horizontal directions is different from the arrangement in the same vertical and horizontal numbers as in the first embodiment. Therefore, in this case, the fuel cell stack is rectangular when viewed from the axial direction.

  As shown in FIG. 11, as a method of arranging the fuel cell units 91, as in the first embodiment, in addition to the square lattice shape as viewed from the axial direction, for example, the positions are shifted by half in the upper and lower rows. It may be a houndstooth pattern.

  (4) In addition, as shown in FIG. 12, the structure of the fuel cell stack is such that the cylindrical fuel cell portion 103 is formed only on one surface (upper side of the figure) of the porous conductive plate 101. A groove 105 to be completely fitted may be provided, and one surface (downward in the figure) may be flat without providing a groove.

  (5) In addition to the reactor using the solid electrolyte as the solid processing layer, the present invention can be applied to a reactor using the above-described palladium metal film, palladium / silver alloy film, or the like.

  (6) Further, in Example 3, an example using a porous conductive plate was given. However, in the case of a reactor that does not require conductivity, a porous plate (with no conductivity) ( However, the same average particle diameter as in Example 3 can be used. For example, any of alumina, zirconia, magnesia, thania, a mixture thereof, and a compound can be used.

1 is a perspective view showing a solid oxide fuel cell stack of Example 1. FIG. It is sectional drawing which expands and shows a part of AA cross section of FIG. 1 is a perspective view showing a fuel cell unit used in a solid oxide fuel cell stack of Example 1. FIG. 2 is a perspective view showing a conductive plate used in the solid oxide fuel cell stack of Example 1. FIG. 2 is an explanatory diagram showing a method for manufacturing a solid oxide fuel cell stack of Example 1. FIG. It is explanatory drawing which shows the experimental method of an experiment example. 6 is a perspective view showing a fuel cell unit used in the solid oxide fuel cell stack of Example 2. FIG. 6 is an enlarged cross-sectional view of a fuel cell unit used in Example 2. FIG. 6 is an explanatory view showing a method for producing a solid oxide fuel cell stack of Example 2. FIG. It is sectional drawing which shows the cross section of the internal electrode of another fuel cell part. It is explanatory drawing which shows the other arrangement | sequence method of a fuel cell part. It is explanatory drawing which shows the other structure of a fuel cell stack. It is a graph which shows the relationship between the gas amount permeate | transmitted with respect to a gas permeability coefficient, and the gas amount required at the time of electric power generation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell stack 3, 91, 103 ... Fuel cell part 5 ... Fuel cell layered part 7 ... Air electrode (outer electrode)
8 ... Fuel cell 9, 101 ... Conductive plate 11 ... Fuel electrode (inner electrode)
13 ... Solid electrolyte layer

Claims (19)

A cylindrical fuel cell unit having a cylindrical inner electrode and a cylindrical solid electrolyte layer formed on the outer peripheral surface thereof includes a plurality of fuel cell layered units arranged in parallel,
The fuel cell layered portion is sandwiched between conductive plates made of porous conductive ceramics in the thickness direction, and an outer electrode of the fuel cell unit is interposed between the solid electrolyte layer and the conductive plate-shaped body. A fuel cell stack comprising the fuel cell stack.   The conductive plate-like body includes a plurality of parallel grooves into which the fuel cell unit is fitted on the surface thereof, and the fuel cell unit is fitted into the groove and fixed between the conductive plate-like members. The fuel cell stack according to claim 1, wherein the fuel cell stack is formed. 3. The fuel cell stack according to claim 1, wherein the conductive plate member has a gas permeability coefficient of 5 × 10 ⁻⁵ cm ² · sec ⁻¹ · Pa ⁻¹ or more. 4. The fuel cell stack according to claim 3, wherein the conductive plate-like body has a gas permeability coefficient of 1 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more. 5. The fuel cell stack according to claim 4, wherein the conductive plate-like body has a gas permeability coefficient of 5 × 10 ⁻⁴ cm ² · sec ⁻¹ · Pa ⁻¹ or more.   The particles in the structure of the conductive plate-like body have an average particle diameter of 10 to 60 µm, and the porosity of the conductive plate-like body is 40 to 60%. The fuel cell stack according to any one of 5.   The particles in the structure of the conductive plate-like body have an average particle diameter of 1 to 10 µm, and the porosity of the conductive plate-like body is 50 to 90%. The fuel cell stack according to any one of 5.   8. The fuel cell according to claim 7, wherein the conductive plate-like body has a maximum pore diameter of 10 to 300 [mu] m, and at least a part of the pores communicates with each other. stack.   The relationship between the porosity and the particle diameter of the conductive plate-like body is (maximum pore diameter / 100) <average particle diameter <(maximum pore diameter / 4), The fuel cell stack described.   The fuel cell stack according to any one of claims 1 to 9, wherein the particles in the structure of the outer electrode have an average particle diameter of 0.1 to 2 µm.   The fuel cell stack according to any one of claims 1 to 10, wherein the outer electrode connects the solid electrolyte layer and a conductive plate-like body.   The fuel cell stack according to any one of claims 1 to 11, wherein the inner electrode is a support of the fuel cell unit, and the thickness of the solid electrolyte layer is 30 µm or less. In the manufacturing method of the fuel cell stack according to any one of claims 1 to 12 ,
A first step of producing a fuel cell part precursor comprising the inner electrode and a solid electrolyte layer formed on the inner electrode or a sintered body of the fuel cell part precursor;
A second step of producing a conductive plate precursor or a sintered body of a conductive plate precursor made of the porous conductive ceramic material;
Stacking the fuel cell part precursor with a conductive plate precursor, stacking the fuel cell part precursor with a conductive plate precursor, and stacking the fuel cell part precursor A third step of stacking the fuel cell part precursor with a sintered body of the conductive plate precursor, or stacking the fuel cell part precursor with a sintered body of the conductive plate precursor When,
A method for producing a fuel cell stack, comprising: Between the fuel cell part precursor and the conductive plate precursor, between the sintered body of the fuel cell part precursor and the conductive plate precursor, the fuel cell part precursor and the The material of the outer electrode is disposed between the sintered body of the conductive plate precursor or between the fired body of the fuel cell unit precursor and the fired body of the conductive plate precursor. 14. The method of manufacturing a fuel cell stack according to claim 13 , wherein firing is performed. The method for producing a fuel cell stack according to claim 13 or 14 , wherein the inner electrode precursor is produced by extrusion molding. The method for producing a fuel cell stack according to any one of claims 13 to 15 , wherein the conductive plate precursor is produced by extrusion molding. In the manufacturing method of the fuel cell stack according to any one of claims 1 to 12 ,
A sintered plate having pores by forming a conductive plate precursor using a raw material obtained by adding a spherical pore former to the porous conductive ceramic, and firing the conductive plate precursor. A method for producing a fuel cell stack, comprising producing the conductive plate-like body. The method for manufacturing a fuel cell stack according to claim 17 , wherein a volume ratio of the spherical pore former to the raw material is 60 to 90% by volume. The method for producing a fuel cell stack according to claim 17 or 18 , wherein a firing temperature of the conductive plate precursor is 1300 ° C or higher.