JP2007123128A - Electrochemical reactor stack and electrochemical reaction system comprising it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical reactor stack capable of achieving miniaturization and increase of efficiency; and to provide an electrochemical reaction system using it. <P>SOLUTION: In an electrochemical reactor cell stack, each reactor cell has a raft-like structure wherein an ion conductor (ion conduction phase) is stacked on a compact comprising a plurality of hollow tube-bound bodies each formed of an anode (fuel electrode) material; and this electrochemical reactor stack is composed by stacking a cathode (air electrode) on the compact. This electrochemical reaction system comprises it. A cathode material can be stacked on an electrolyte layer on the tube by accurately controlling it, and thereby the electrochemical reaction system such as a solid oxide type fuel cell capable of lowering its operation temperature can be provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrochemical reactor stack and an electrochemical reaction system such as a solid oxide fuel cell composed of the reactor stack. More specifically, the present invention can be easily stacked and an air flow path. A cell stack that can be freely designed and formed in series and in parallel within the module, and using this cell stack to lower the operating temperature and greatly increase the power generation voltage per unit module The present invention relates to an electrochemical reaction system that makes it possible. The present invention provides an electrochemical reactor stack suitably used as a clean energy source, an environmental purification device, and the like, and a new technology and a new product relating to an electrochemical reaction system using the reactor stack.

  As a typical electrochemical reactor, there is a solid oxide fuel cell (hereinafter referred to as “SOFC”). The SOFC is a fuel cell using a solid oxide electrolyte having ionic conductivity as an electrolyte. The basic structure of the SOFC is usually composed of three layers of cathode-solid oxide electrolyte-anode, and the SOFC is usually used in a temperature range of 800 to 1000 ° C.

  When fuel gas (hydrogen, carbon monoxide, hydrocarbon, etc.) is supplied to the anode of the SOFC and air, oxygen, etc. are supplied to the cathode, there is a difference between the oxygen partial pressure on the cathode side and the oxygen partial pressure on the anode side. Therefore, a voltage according to the Nernst equation is generated between the electrodes. Oxygen becomes ions at the cathode and moves to the anode side through the solid electrolyte, and the oxygen ions reaching the anode react with the fuel gas and release electrons. Therefore, for example, if a load is connected to the anode and cathode of this SOFC, electricity can be directly taken out as a fuel cell.

  In the future, in order to put SOFC into practical use, it is essential to lower the operating temperature of SOFC. By reducing the operating temperature to 800 ° C. or lower, particularly 500 to 600 ° C., use of inexpensive materials and a reduction in operating cost can be expected, and the versatility of SOFC is expected to increase by lowering the operating temperature. In addition, due to the lowering of operating temperature, the SOFC characteristics become highly dependent on the electrode structure in the low temperature operating range, and it is important to lower the process temperature in the SOFC manufacturing process to control the structure. It becomes.

  In order to lower the operating temperature of SOFC, it is inevitable to make the electrolyte thin, and so far, electrode support type cells, particularly anode support type cells, have been widely studied (Non-patent Document 1). In addition, it is expected that further miniaturization of SOFC will lead to the production of new markets such as use as an auxiliary power source for automobiles and portable power sources. For this purpose, it is necessary to improve the cell surface area per unit volume, and an SOFC structure composed of tubular cells has also been proposed (Patent Document 1).

  However, the tubular cell modules proposed so far have a structure in which the tube cell is stably held by the cathode material, and as the tube diameter becomes smaller, the packing of the tubular cell becomes difficult. There was a problem. Further, this structure has problems such as difficulty in securing an air gas flow path and the need to use a large amount of expensive cathode material, and all the tubes are connected in parallel. Therefore, there is a limitation that the voltage per module is about 1V.

JP 2004-335277 A Nikkei Mechanical separate volume, fuel cell development forefront, Nikkei BP, June 29, 2001, p. 71-80

  Under such circumstances, the present inventors have developed a tubular cell that can surely solve the problems of the above-described conventional members and a new usage form thereof in view of the above-described conventional technology. As a result of intensive research as a goal, a structure in which a plurality of tubular anodes (fuel electrodes) are connected to each other in a plane is constructed, and an electrolyte layer and a cathode (air electrode) are formed on the structure. Therefore, it is possible to provide a cell stack in which cells can be easily integrated and a sufficient air passage can be provided, and a cell stack in which series and parallel connections can be freely designed and formed in a module can be provided. It is possible to provide a cell stack that can greatly increase the power generation voltage in the unit module, and to reduce the operating temperature by using the cell stack. Ability to provide an electrochemical reaction system, found a novel finding etc., further extensive research, and completed the present invention.

  The present invention provides a cell stack that can be easily integrated and has a sufficient air passage, and also provides a cell stack in which series and parallel connections can be freely designed and formed in a module. It is possible to provide a cell stack that can greatly increase the power generation voltage in the unit module, and to use the cell stack to lower the operating temperature and greatly increase the power generation voltage per unit module. It is an object of the present invention to provide an electrochemical reaction system. Another object of the present invention is to provide a cell stack capable of significantly reducing the amount of expensive cathode material used in the conventional tubular cell and a reactor system using the cell stack. It is what.

The present invention for solving the above-described problems comprises the following technical means.
(1) A structure in which a plurality of tubular anodes (fuel electrodes) having an electrolyte layer (ion conduction phase) on the surface are coupled to each other is formed, and a cathode (air electrode) is formed on the electrolyte layer of the structure. ) Are stacked, an electrochemical reactor stack.
(2) A structure in which a plurality of tubular anodes (fuel electrodes) capable of forming an electrolyte layer (ion conduction phase) on the surface is coupled to each other is formed, and the electrolyte layer (ion conductor) is formed on the structure. Electrochemical reactor stack characterized in that a phase) and a cathode (air electrode) are laminated.
(3) The electrochemical reactor stack according to the above (1) or (2), wherein a plurality of tubular anodes (fuel electrodes) form a structure in which the anodes are joined in a plane.
(4) The electrolyte material is composed of two or more elements selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W. The electrochemical reactor stack according to (1) or (2), wherein the electrochemical reactor stack is an oxide compound.
(5) An oxidation in which the tubular anode (fuel electrode) material contains an electrolyte material, Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, Ti and / or one or more of these elements The electrochemical reactor stack according to (1) or (2), which is composed of a physical compound.
(6) The cathode (air electrode) material is composed of an Ag, La, Sr, Mn, Co, Fe, Sm, Ca, Ba, Ni, Mg element and / or an oxide compound containing one or more of these elements. The electrochemical reactor stack according to (1) or (2).
(7) The electrochemical reactor stack according to (6) above, wherein the cathode material is a transition metal perovskite oxide or a composite of a transition metal perovskite oxide and a solid electrolyte material.
(8) The electrochemical reactor stack according to (1) or (2), wherein the electrolyte layer has a thickness of 1 to 100 microns.
(9) An electrochemical reaction system for taking out an electric current by an electrochemical reaction, comprising the electrochemical reactor stack according to any one of (1) to (8) as a component as a reactor. .
(10) The electrochemical reaction system according to (9), wherein a plurality of the electrochemical reactor stacks are integrated and modularized.
(11) The electrochemical reaction system according to (9) or (10), wherein the electrochemical reaction system is a solid oxide fuel cell, an exhaust gas purification electrochemical reactor, or a hydrogen production electrochemical reactor.

Next, the present invention will be described in more detail.
The electrochemical reactor stack according to the present invention is a so-called raft in which a plurality of ceramic hollow tubular anodes (fuel electrodes) having an electrolyte layer (ion conducting phase) on the surface are assembled and bonded in parallel (one-dimensional) with each other. A hollow tubular anode lined up by an electrolyte layer is bonded, or an electrolyte layer is laminated on the anode tube joined together, and a cathode (air electrode) is formed on the electrolyte layer. ) Are laminated.

  Conventionally, when producing a tube-type electrochemical cell, an anode material is produced as a tube (usually including sintering at 1400 ° C. or higher), and an electrolyte is laminated and sintered (usually at 1400 ° C. or higher). In addition, a plurality of process steps were required in which a tube was placed in the cathode structure and further sintered (usually 1000 ° C. or higher). In that case, when the tube diameter becomes a microtube having a diameter of 2 mm or less, the construction of the process becomes more difficult. However, according to the configuration of the electrochemical reactor stack of the present invention, a raft-like structure in which the tubular anodes are assembled and bonded in a plane is first produced by the tubular anodes before firing. Simultaneous firing of the anode tube and construction of an electrochemical cell structure are possible, and a structure that can be easily handled even with a microcell having a tube diameter of 2 mm or less is obtained.

  In addition, according to the configuration of the electrochemical reactor stack, the cathode material can be laminated on the electrolyte layer of the raft-shaped structure with a required thickness controlled with an arbitrary thickness with high accuracy. It is possible to construct an electrochemical reactor stack that can realize an electrochemical reactor stack with excellent cost performance and a low operating temperature (about 400 to 650 ° C.) using the electrochemical reactor stack. It becomes. Examples of the electrochemical reaction system of the present invention include a solid oxide fuel cell (SOFC), an exhaust gas purification electrochemical reactor, a hydrogen production electrochemical reactor, and the like. In the electrochemical reactor stack, an anode, an electrolyte, a cathode By appropriately selecting the material, it is possible to construct an electrochemical reaction system such as a highly efficient SOFC, for example.

  In the present invention, from the viewpoint that a material having high ionic conductivity is essential for the electrolyte material, Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, An oxide compound containing two or more elements selected from Bi, Nb, and W is desirable.

  The hollow tube-shaped anode material preferably includes a material having high activity with respect to the fuel gas. The electrolyte material and the elements of Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, Ti It is necessary to realize a highly efficient electric chemical reactor that has at least one type of oxide compound. Further, the cathode (air electrode) material is preferably a material having high activity for ionization of oxygen, and in particular, elements of Ag, La, Sr, Mn, Co, Fe, Sm, Ca, Ba, Ni, Mg and / or oxidation. A material composed of one or more compounds is preferred. Hereinafter, an electrochemical reactor stack and an electrochemical reaction system including the electrochemical reactor stack according to an embodiment of the present invention will be described in detail.

  First, the structure of the electrochemical reactor stack according to the present invention will be described. FIG. 1 is a schematic view of an electrochemical reactor stack according to the present invention. For example, the types shown in FIG. In the type of FIG. 1 a, a plurality of tubular anodes (fuel electrodes) having a dense electrolyte layer 1 on the surface are connected to each other in a plane by the electrolyte layer. In this case, the electrolyte layer functions as a medium for binding the tubular anode. And an electrochemical reactor stack is comprised by arrange | positioning the cathode 4 outside the electrolyte layer. In the type of FIG. 1b, a plurality of tubular anodes are coupled to each other in a planar manner. In this case, the tubes of the plurality of tubular anodes are bonded and bonded in advance, but the bonding method and means are not particularly limited, and appropriate methods and means can be used. And the electrochemical reactor stack is comprised by laminating | stacking the electrolyte layer 1 and the cathode 4 on the surface. In the present invention, the number of anode tubes per unit when the above-mentioned anode tubes are one-dimensionally arranged and coupled is arbitrary, and their coupling method is also arbitrary.

  First, the electrolyte layer 1 will be described. The thickness of the electrolyte layer 1 needs to be determined in consideration of the tube diameter of the porous tube, the specific resistance of the solid electrolyte layer itself, and the like. The electrolyte layer 1 is preferably dense and has a thickness in the range of 1 to 100 microns, and the particle size of the electrolyte material is preferably 50 microns or less in order to suppress the electric resistance of the electrolyte. preferable. Since this electrolyte layer is laminated on the surface of the anode tube, it is possible to easily reduce the thickness of the electrolyte layer and to control the thickness with high accuracy. Normally, under the conditions of use as a fuel cell, a fuel gas such as hydrogen, carbon monoxide, or methane is supplied to the tube hole 4, and an oxidant gas such as air or oxygen is supplied to the cathode side. However, their specific configuration can be arbitrarily designed.

  Here, in the electrochemical reactor stack according to the present invention, the tube diameter, the tube length, and the tube thickness of the tubular anode are not particularly limited, and the entire size of the required electrochemical reactor stack is considered. In addition, it can be arbitrarily set so as to obtain necessary characteristics as an anode. The porosity of the tubular anode is preferably 30 to 60%, but is not limited to this, so that the three-phase interface (reaction field) is maintained and the tube strength does not decrease. In addition, various controls can be performed within the preferable range. Moreover, a and b of FIG. 1 are specific examples of the structure obtained by the difference in the manufacturing process, and both are exemplified as preferable examples of the present invention.

  As the electrolyte material, it is necessary to use a material that realizes high ion conduction. As materials used for these, Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, An oxide compound containing two or more kinds of elements selected from Ba, La, Sr, Ga, Bi, Nb, and W is exemplified as desirable.

Among them, stabilizers such as yttria (Y ₂ O ₃ ), calcia (CaO), scandia (Sc ₂ O ₃ ), magnesia (MgO), ytterbia (Yb ₂ O ₃ ), erbia (Er ₂ O ₃ ), etc. Stabilized zirconia, yttria (Y ₂ O ₃ ), gadolinia (Gd ₂ O ₃ ), ceria (CeO ₂ ) doped with samaria (Sm ₂ O ₃ ), and the like are preferable examples. The stabilized zirconia is preferably stabilized with one or more stabilizers, and is preferably a composite with alumina (Al ₂ O ₃ ).

  Specifically, yttria-stabilized zirconia (YSZ) added with 5 to 10 mol% yttria as a stabilizer, gadolinia doped ceria (GDC) added with 5 to 10 mol% gadolinia as a dopant, and the like are preferable examples. Can be mentioned. For example, in the case of YSZ, it is not preferable that the yttria content is less than 5 mol% because the oxygen ion conductivity of the anode is lowered. On the other hand, if the yttria content exceeds 10 mol%, the oxygen ion conductivity of the anode similarly decreases, which is not preferable. The same applies to GDC.

  The material of the tubular anode needs to be a composite composed of a mixture of anode material and electrolyte material. The anode material is a metal selected from Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, Ti and / or an oxide composed of one or more of these elements, and is also a catalyst. Specifically, nickel (Ni), cobalt (Co), ruthenium (Ru), etc. are mentioned as a suitable example. Among these, nickel (Ni) can be suitably used because it is cheaper than other metals and has a sufficiently high reactivity with fuel gas such as hydrogen. It is also possible to use a composite in which these elements and oxides are mixed.

  Here, in the composite of the anode material and the electrolyte material, the mixing ratio of the former and the latter is preferably in the range of 90:10 wt% to 40:60 wt%, and the balance of electrode activity, consistency of thermal expansion coefficient, etc. More preferably, it is 80: 20% by weight to 50: 50% by weight.

  On the other hand, the cathode material is preferably a material having high activity for ionization of oxygen, and in particular, Ag, La, Sr, Mn, Co, Fe, Sm, Ca, Ba, Ni, Mg, and / or oxidation thereof. A material composed of one or more physical compounds is preferred. Among them, for example, transition metal perovskite oxides, and composites of transition metal perovskite oxides and electrolyte materials can be preferably used. In the case of using the above composite, oxygen ion conductivity is improved among the electron conductivity and oxygen ion conductivity, which are characteristics necessary for the cathode, so that oxygen ions generated at the cathode easily migrate to the electrolyte layer. Thus, there is an advantage that the electrode activity of the cathode is improved.

  Here, when a composite of a transition metal perovskite oxide and a solid electrolyte material is used, the mixing ratio of the former and the latter is preferably in the range of 95: 5 wt% to 60:40 wt%. From the viewpoint of excellent balance such as coefficient consistency, it is more preferably 90:10 wt% to 70:30 wt%.

Specific examples of the transition metal perovskite oxide include LaSrMnO ₃ , LaCaMnO ₃ , LaMgMnO ₃ , LaSrCoO ₃ , LaCaCoO ₃ , LaSrFeO ₃ , LaSrCoFeO ₃ , LaSrNiO ₃ Co, and SmS ₃ Can be mentioned.

  However, as shown in FIG. 1, anode exposed portions 5 are formed at both ends of the anode tube by exposing a part of the anode without the electrolyte layer 1 being laminated. The anode exposed portion 5 functions as an external lead electrode of the anode. The exposure amount of the anode exposed portion 2 is not particularly limited, and can be appropriately adjusted in consideration of a gas sealing material, an electrode current collecting method, a gas outlet channel, and the like.

  Next, an operation method when the electrochemical reactor stack according to the present invention is operated as a single SOFC will be described. As shown in FIG. 2, the anode exposed portion 5 is disposed in the fuel gas introduction pipe 9, and the anode exposed portion 2 is sealed in the fuel gas introduction pipe 9 by a gas sealing material 8. Specific examples of the main material constituting the fuel gas introduction means include heat-resistant stainless steel and ceramics depending on the operating conditions of the SOFC.

That is, the anode exposed portion 5 of the electrochemical reactor stack is mounted inside the fuel gas introduction pipe 9, and each electrode connection portion is sealed with a gas sealing material 8. The material for the gas sealing material 8 is not particularly limited as long as it does not allow gas to pass therethrough. However, it is necessary to match the thermal expansion coefficient of the anode portion. Specifically, mica glass, ceramics such as spinel (MgAl ₂ O ₄ ), and the like are preferable examples.

A current collector 10 is attached to the electrode surface (the anode exposed portion 5 and the cathode 4). Specific examples of the main material constituting the current collector 10 include conductive ceramics such as lanthanum chromite (LaCrO ₃ ), noble metal meshes such as gold, silver and platinum, stainless steel, nickel mesh, nickel felt, and the like. An example.

  Further, using an oxidant gas or fuel gas introduction means (for example, an external manifold), the fuel gas is introduced into the anode part and the oxidant gas is introduced from the outside of the cell stack, and collected at the pipe connection part and the current collector 10. By connecting the load 12 via the electric wire 11, power generation is possible.

  In the above description, one operation method in the case where the electrochemical reactor stack according to the present invention is operated as a single SOFC has been described. However, the operation method is not limited to the SOFC, and the hydrogen production electric It can also be applied to chemical reactors and exhaust gas purification electrochemical reactors. It is also possible to construct a power generation apparatus in which the electrochemical reactor stack according to the present invention is electrically connected in series to form a module. At that time, the use of the electrochemical reactor stack facilitates the configuration of a space-saving module for generating a high voltage.

  Next, the operation of the electrochemical reactor stack according to the present invention will be described. In the electrochemical reactor stack according to the present invention, for example, a dense electrolyte layer is laminated on a hollow tube-shaped anode (fuel electrode), and the tube-shaped anode is formed one-dimensionally in a plane to form a raft shape. And a cathode is formed outside the electrolyte layer.

  Conventionally, the production of a cell stack using cells having a tube diameter of 2 mm or less has been extremely difficult due to the difficulty of handling. However, according to the structure of the electrochemical reactor stack, first, a raft-like structure is produced by the tube-like anode, so that a structure that can be easily handled even with a microtube having a tube diameter of 2 mm or less is obtained. In addition, the structure which is desired to be manufactured can be easily stacked due to the structure, and the module voltage per volume can be increased by connecting them in series. In the present invention, the shape, structure, tube diameter and the like of the anode tube are not particularly limited, and can be arbitrarily designed.

  Moreover, according to the structure of the above electrochemical reactor stack, the cathode material can be laminated in the electrolyte layer on the tube in an arbitrary thickness in the required amount, thereby making the electrochemical reactor excellent in cost performance. You can build a stack. Next, the suitable manufacturing method of the electrochemical reactor stack of this invention is demonstrated. The method for producing an electrochemical reactor stack according to the present invention basically includes the following steps.

  That is, the method of manufacturing an electrochemical reactor stack according to the present invention includes a step of manufacturing an anode tube, a step of bonding a solid electrolyte layer to the outer surface of the anode tube, and assembling and bonding the tubes to manufacture a raft structure. And a step of applying and sintering a cathode material on the outside of the solid electrolyte layer on the raft structure. Hereinafter, these will be described in detail.

  First, an anode tube is made using a mixture of anode material and electrolyte material. Specifically, an oxidation containing two or more elements selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W. A powder of a physical compound, a powder of a metal element or oxide selected from Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, and Ti; And kneading with water, and the resulting plastic mixture is extruded to form a tubular formed body having a predetermined tube diameter, tube length, and tube thickness. These methods and means for producing the tubular molded body are not particularly limited, and appropriate methods and means can be used.

  Next, after the slurry containing the electrolyte material powder is attached to the obtained tubular anode molded body, it is arranged in a raft shape and dried. As a result, an electrolyte layer forming layer that becomes a solid electrolyte layer is attached to the surface of the tube by subsequent firing, and a raft structure is obtained in which the tubes are joined by the electrolyte layer (a in FIG. 1). Moreover, it is possible to obtain a raft-like structure by an anode tube by bonding the obtained tube-shaped molded body before drying, and thereafter, a slurry containing an electrolyte material powder is adhered and dried (see FIG. 1 b).

  Examples of the method for attaching the slurry include a method in which openings on both ends of a porous tube are sealed with a resin adhesive, and then the tube is immersed in a slurry containing a solid electrolyte and dip coated. Although it is mentioned as a suitable example, it is not limited to this, and various attachment methods such as a brush coating method and a spray method can be used in addition to the dip coating method.

  At this time, it is necessary that an exposed portion in which the anode portion is exposed is formed on one end of the outer surface of the obtained tubular anode with an electrolyte layer without adhering slurry containing a solid electrolyte. . This is fired at a predetermined temperature to obtain a tube structure with an electrolyte layer. The tube structure is preferably fired at a temperature of about 1200 to 1600 ° C., but is not particularly limited to this range. In consideration of the material of the tube, the porosity, etc., the electrolyte layer The temperature at which the density is densified to about 90% or more is arbitrarily set.

  A cathode material is then applied to the electrolyte layer. As the cathode material, in particular, a material composed of one or more of Ag, La, Sr, Mn, Co, Fe, Sm, Ca, Ba, Ni, Mg and / or an oxide compound thereof is suitable. A slurry can be prepared from these powders, and the cathode can be formed on the electrolyte layer using the same method as that for the preparation of the solid electrolyte.

  Next, the obtained tube structure is fired at a predetermined temperature to form an electrochemical reactor stack. In this case, the firing temperature is preferably about 800 to 1200 ° C., but is not particularly limited and can be variously adjusted in consideration of the type of the cathode material and the like. As described above, an electrochemical reactor stack having a structure in which the solid electrolyte layer 1 is bonded to the outer surface of the anode tube 2 and the cathode 3 is laminated on the outer side of the electrolyte layer can be obtained.

  If necessary, for example, the cathode or anode portion of the obtained electrochemical reactor stack can be machined to adjust the surface and adjust the dimensions accordingly. In the above manufacturing method, the case where the cathode is laminated after the porous tube assembly with the electrolyte is prepared in advance by firing the tube coated with the slurry of the electrolyte material. It is also possible to produce an anode tube with electrolyte first, and then join the tubes together with a cathode material slurry to form a raft-like structure.

  When these electrochemical reactor stacks are stacked as a stack, for example, as shown in FIG. 3, tubes are arranged in parallel, and a common fuel gas introduction and current collecting manifold 13 is formed in each tube structure. can do. The manifold on the anode side can be used as an electrochemical reactor capable of multivolt power generation by being connected to a cathode current collector on the upper stage via an interconnect or the like.

  In addition, when the stack is constructed using the electrochemical reactor stack, the tubes to which the electrolyte layers are joined can be integrally joined with the cathode material, so that it has been difficult to connect them conventionally. Even when the outside of the tube is in an oxidizing atmosphere, the tubes can be easily electrically connected without using an expensive precious metal wire or the like. The method, means and form of laminating the electrochemical reactor of the present invention as a stack are not particularly limited, and can be arbitrarily selected and designed according to the type and purpose of use. In the present invention, an appropriate electrochemical reaction system can be constructed by incorporating the electrochemical reactor stack as a reactor in the electrochemical reaction system, and the production method and means thereof are not particularly limited.

The following effects are exhibited by the present invention.
(1) According to the present invention, an electrochemical reactor stack having a novel cell structure and suitably used as a clean energy source, an environmental purification device, or the like can be provided.
(2) An electrochemical reaction system such as a solid oxide fuel cell using the electrochemical reactor stack can be provided.
(3) A structure of an electrochemical reactor stack that can be easily handled even with a microtube having a tube diameter of 2 mm or less can be constructed.
(4) By using a stack having a one-dimensional structure composed of a raft-like structure, it is possible to easily form a module by serial joining, thereby greatly improving the power generation voltage per module. Become.
(5) Since the process temperature in the manufacturing process of the tubular anode can be lowered, it is possible to use an inexpensive cathode material, and to solve the problem of the conventional material in which a large amount of an expensive cathode material is used. it can.
(6) The thickness of the electrolyte layer can be reduced and the surface area per unit surface can be greatly increased, and the cathode material can be laminated on the electrolyte layer at an arbitrary thickness with high precision, It is possible to provide an electrochemical reaction system capable of improving cost performance and reducing the operating temperature to about 400 to 650 ° C.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

In this example, an electrochemical reactor stack was produced according to the following procedure. First, nitrocellulose as a binder and carbon powder as a pore-forming agent are added to a powder having a ZrO ₂ -10 mol% Y ₂ O ₃ composition (made by Tosoh Corporation), kneaded with water to form a clay, and then extruded. A tubular molded body was molded by a molding method. The tube diameter and tube thickness of the obtained tubular molded body were 1.5 mm and 0.4 mm, respectively (tube outer diameter 1.5 mm, tube inner diameter 0.7 mm).

Next, the obtained tubular molded body was made 2 cm long, and the opening at one end was sealed with vinyl acetate, and then this tube was immersed in a slurry containing a solid electrolyte having a composition of ZrO ₂ -10 mol% Y ₂ O _3. Then, the electrolyte layer was dip coated to obtain a tubular molded body with an electrolyte. A raft-like structure was prepared by closely attaching five tubes with electrolyte. Thereafter, the other end of the anode tube was exposed by 5 mm to form an exposed portion.

  Next, this coil-shaped molded body was dried and then fired at 1450 ° C. for 2 hours to obtain a raft-like structure with an electrolyte. FIG. 4 shows an enlarged cross-sectional photograph. It can be seen that the tubes are joined by the electrolyte material.

Next, a paste containing LaSrCoFeO ₃ (manufactured by Nippon Ceramics Co., Ltd.) as a cathode material in the container was applied to the electrolyte layer surface, dried at 100 ° C., and then fired at 1000 ° C. for 1 hour. Thereby, an electrochemical reactor stack was obtained.

  The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiment, only a single raft-like structure is shown. However, when a stack is constructed, it can be manufactured by the same procedure.

  As described above in detail, the present invention relates to an electrochemical reactor stack and an electrochemical reaction system composed thereof. According to the configuration of the electrochemical reactor stack of the present invention, first, a raft-like shape is formed by a tube. Since the structure is produced, a structure that can be easily handled even with a microtube having a tube diameter of 2 mm or less is obtained. Since the raft-like structure is a one-dimensional structure stack, it can be easily connected in series when modularized. Therefore, it is possible to generate a higher voltage than a conventional member per module. In addition, according to the above configuration, the cathode material can be stacked in a required amount on the electrolyte layer on the coil, thereby enabling an electrochemical reactor stack with excellent cost performance and a lower operating temperature. An electrochemical reaction system can be constructed.

1 is a schematic view of an electrochemical reactor stack according to the present invention. It is a block diagram in the case of using the electrochemical reactor stack which concerns on this invention as SOFC single-piece | unit. It is an example of modularization using the electrochemical reactor stack which concerns on this invention. It is an expanded sectional view of the electrochemical reactor stack which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte layer 2 Anode tube 3 Tube empty 4 Cathode 5 Anode exposed part 6 Fuel gas 7 Air 8 Sealing material 9 Fuel gas introduction pipe 10 Current collector 11 Current collection wire 12 Load 13 Manifold

Claims (11)

  A structure in which a plurality of tubular anodes (fuel electrodes) having an electrolyte layer (ion conduction phase) on the surface is connected to each other is formed, and a cathode (air electrode) is laminated on the electrolyte layer of the structure. Electrochemical reactor stack characterized by being made.   A structure in which a plurality of tubular anodes (fuel electrodes) capable of forming an electrolyte layer (ion conduction phase) on the surface is bonded to each other is formed, and the electrolyte layer (ion conductor phase) and the structure are formed on the structure. Electrochemical reactor stack, characterized in that a cathode (air electrode) is laminated.   The electrochemical reactor stack according to claim 1 or 2, wherein a plurality of tubular anodes (fuel electrodes) form a structure in which the anodes are planarly coupled to each other.   An oxide containing two or more elements selected from Zr, Ce, Mg, Sc, Ti, Al, Y, Ca, Gd, Sm, Ba, La, Sr, Ga, Bi, Nb, and W The electrochemical reactor stack according to claim 1, which is a compound.   The tubular anode (fuel electrode) material is composed of an electrolyte material and an oxide compound containing Ni, Cu, Pt, Pd, Au, Ru, Co, La, Sr, Ti and / or one or more of these elements. The electrochemical reactor stack according to claim 1 or 2, wherein the electrochemical reactor stack is configured.   The cathode (air electrode) material is composed of Ag, La, Sr, Mn, Co, Fe, Sm, Ca, Ba, Ni, Mg elements and / or oxide compounds containing one or more of these elements. The electrochemical reactor stack according to claim 1 or 2.   The electrochemical reactor stack according to claim 6, wherein the cathode material is a transition metal perovskite oxide or a composite of a transition metal perovskite oxide and a solid electrolyte material.   The electrochemical reactor stack according to claim 1 or 2, wherein the electrolyte layer has a thickness of 1 to 100 microns.   A system for taking out an electric current by an electrochemical reaction, comprising the electrochemical reactor stack according to claim 1 as a constituent element as a reactor.   The electrochemical reaction system according to claim 9, wherein the plurality of electrochemical reactor stacks are integrated and modularized.   The electrochemical reaction system according to claim 9 or 10, wherein the electrochemical reaction system is a solid oxide fuel cell, an exhaust gas purification electrochemical reactor, or a hydrogen production electrochemical reactor.