JP5061408B2 - STACK FOR SOLID ELECTROLYTE FUEL CELL AND SOLID ELECTROLYTE FUEL CELL - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid oxide fuel cell that uses a solid electrolyte to obtain electric energy by an electrochemical reaction and a stack used therefor, and more particularly, a cell plate structure and a cell plate in which an electrode and a solid electrolyte are formed. Concerning stack improvements.
[0002]
[Prior art]
In recent years, fuel cells have attracted attention as environmentally friendly clean energy sources capable of high energy conversion. Among them, solid electrolyte type fuel cells are oxide ion conductive solids such as yttria-stabilized zirconia as electrolytes. It is a battery of the type that uses an electrolyte, attaches porous electrodes on both sides, supplies fuel gas such as hydrogen and hydrocarbons on one side and air or oxygen gas on the other side with the solid electrolyte as a partition, The fuel cell operates at about 1000 ° C.
[0003]
It is known that the conductivity of such a solid electrolyte is about an order of magnitude lower than the conductivity of electrolytes of phosphoric acid fuel cells and molten carbonate fuel cells. In general, since the electrical resistance of the electrolyte part becomes a power generation loss, in order to improve the power generation output density, it is important to reduce the film resistance as much as possible by reducing the thickness of the solid electrolyte. In order to ensure the function, an area larger than a certain size is required. Therefore, in a solid oxide fuel cell, a cell structure (single cell structure) in which a solid electrolyte membrane is formed on a support having mechanical strength is used. It has been adopted. As a specific fuel cell structure, the following structure has been proposed.
[0004]
(1) Cylindrical type
A cylindrical and porous base tube is used as a support, and a cell structure is formed by laminating a fuel electrode layer, an electrolyte layer, and an air electrode layer on the surface of the base tube.
There are a cylindrical horizontal stripe type in which a plurality of single cell structures are arranged on one base tube, and a cylindrical vertical stripe type in which one single cell is formed on a single base tube. In either type, a battery is constructed by electrically connecting a plurality of cylinders with an interconnector, and either one of fuel gas or air is introduced into the inside of the substrate tube, and the other is introduced outside the substrate tube. Power is generated by introducing gas. Such a cylindrical solid oxide fuel cell has a feature that does not particularly require a seal between the fuel gas and the air because one of the fuel gas and the air flows in the base tube. In addition, because it is cylindrical, it has the advantage of being resistant to thermal shocks associated with starting and stopping of the fuel cell, and it is possible to design a stack that maintains the manifold part connected to the gas piping at a relatively low temperature, which is durable. Is characterized by high.
[0005]
(2) Flat plate type (1)
Basically, it has the same structure as phosphoric acid type or carbonated molten salt type. That is, a separator plate in which a fuel electrode plate having a fuel gas flow path formed on both sides of an interconnector plate and an air electrode plate having an air flow path bonded together, and a fuel electrode layer and an air electrode layer on both sides of a sheet-like electrolyte layer It is the structure which stuck together the planar cell board which laminated | stacked.
In order to reduce the IR loss of the power generation output and improve the output density, it is considered important to make the electrolyte layer thin, and support either the porous fuel electrode or the air electrode. A cell structure in which an electrolyte membrane and the other electrode layer are formed as a body has been proposed. For example, a configuration in which an electrolyte layer having a film thickness of 15 μm is formed on a 1.5 mm thick Ni-cermet fuel electrode layer by a vacuum slip casting method (Proceedings of The 3rd International Fuel Cell Conference, P349) is disclosed.
In this flat plate type, the effective power generation cell area that can be installed per unit volume of the fuel cell can be increased as compared with the cylindrical type, and thus the output density can be improved.
[0006]
(3) Flat plate type (2)
In the flat plate type {circle around (1)} described above, damage due to the difference in thermal expansion coefficients among the fuel electrode plate, air electrode plate, and interconnector plate constituting the separator plate is prevented to improve the thermal durability. Alternatively, improving the heat resistance of the interconnector flat plate against both fuel gas (reducing atmosphere) and air (oxidizing atmosphere) is a major technical issue.
In order to improve this, the fuel electrodes and the air electrodes are stacked so as to face each other, and the fuel gas flow path is made of the fuel electrode material between the fuel electrodes, and the air flow is made of the air electrode material between the air electrodes. A fuel cell stack having a configuration in which a path is formed has been proposed (Japanese Patent Laid-Open No. 9-45355). According to this configuration, it is not necessary to use a separator, so that it is possible to further reduce the size and improve the thermal durability.
[0007]
(4) Monolith type
The structure is similar to the flat plate type. That is, a fuel electrode layer in which gas flow paths are not formed on both surfaces of the interconnector flat plate, a separator plate in which an air electrode layer is formed, a corrugated fuel electrode layer, an electrolyte layer, and an air electrode layer are integrated into three layers. It is a structure in which cell films are alternately bonded. The flow path is formed by the corrugated cell plate, and the effective power generation cell area that can be installed per unit volume of the fuel cell stack can be increased, so that the output density can be improved.
[0008]
[Problems to be solved by the invention]
As described above, in order to reduce the size of the fuel cell stack and increase the output density, the effective cell area that can be installed per stack unit volume is increased, and the power generation output per unit cell area is increased. This is very important.
However, in the prior art (1), there is a problem that it is generally difficult to increase the effective power generation cell area that can be installed per unit volume of the fuel cell stack. In particular, miniaturization of the fuel cell stack is important for mounting on a moving body such as an automobile, and for vehicle mounting, it is important to improve start-up performance. There is a problem that it takes time to raise the temperature to a temperature where power generation is possible, and the startability of the fuel cell stack is deteriorated.
[0009]
On the other hand, the prior art (2) generally has a configuration in which the density of the effective cell area can be easily increased.
However, since one surface of the separator plate is exposed to fuel gas and the other surface is exposed to air, it is difficult to improve the heat durability against both gases, and there is a problem in improving the heat durability. In addition, the gas sealability of the manifold part that connects the stack mainly made of ceramic material and the metal gas pipe is not sufficient, and furthermore, since it includes the joint part of different materials of ceramics and metal, it is weak against thermal shock. There is also a problem.
[0010]
In the prior art (3), by using a configuration that does not use a separator, it is possible to improve the durability, which is a problem of the prior art (2), and to improve the effective cell area density per unit stack volume.
However, similarly to the above, there is a problem that the gas sealability and thermal shock resistance of the manifold portion are not sufficient. In this configuration, all the stacked cell plates are electrically connected in parallel, so the fuel cell stack is a low voltage, high current type, and when a high voltage is required, the power generation output of the stack is It is difficult to design, and when boosting or transmitting power, there is a problem that loss is increased in the wiring portion.
[0011]
Furthermore, since the prior art (4) employs a configuration in which the cell plate portion composed of the electrolyte layer and both electrode layers is formed in a corrugated shape to divide the gas flow path, the effective cell per unit stack volume is adopted. The area density can be improved.
However, there is a problem that the mechanical strength is not sufficient, and in order to improve the strength, it is necessary to increase the thickness of the electrolyte. If it is too thick, the membrane resistance of oxygen ion conduction in the electrolyte portion will increase. Therefore, there is a problem that the power generation output per unit cell area is reduced.
[0012]
The present invention has been made paying attention to such problems of the prior art, the purpose of which is to reduce the membrane resistance by reducing the thickness of the electrolyte layer, it is possible to sufficiently ensure the electrode reaction area, It is an object of the present invention to provide a stack for a solid oxide fuel cell and a solid oxide fuel cell using the same, which are highly reliable for use modes in which starting and stopping frequently occur.
[0013]
[Means for Solving the Problems]
As a result of intensive investigations to achieve the above object, the present inventors have given a specific shape to an electrode layer using a predetermined substrate, or appropriately selected the lamination specifications of each layer, etc. Has been achieved, and the present invention has been completed.
[0014]
  That is, the present inventionSolidThe body electrolyte fuel cell stack is a solid oxide fuel cell stack formed by laminating a cell plate sandwiching an air electrode layer and a fuel electrode layer on a solid electrolyte layer.
  The cell plate has a substrate having a groove on the upper surface and / or the lower surface, and a fuel electrode layer, a solid electrolyte layer and an air electrode layer, or an air electrode layer, a solid electrolyte layer and a fuel electrode on the substrate surface on the groove side. These layers laminated in order of layers and substantially transferring the shape of the groove,
  A penetrating opening is partially formed at the bottom of the concave groove, and the fuel electrode layer or the air electrode layer protrudes from the opening,
  At least one pair of the cell plates is laminated so that the fuel electrode layers or the air electrode layers are opposed to each other.,
  The tubular groove formed by joining the fuel electrode layers or the air electrode layers functions as a fuel or air gas flow path.TheIt is characterized by that.
[0015]
  In addition, the present inventionSolidA preferred form of the stack for the body electrolyte fuel cell is characterized in that the substrate is made of a porous material and functions as a gas flow channel having a polarity opposite to that of the gas flow channel handled by the tubular groove.
[0017]
  Furthermore,Of the present inventionA preferred embodiment of the stack for a solid oxide fuel cell is that the substrate and the air electrode are formed in a region other than the through opening, or in this region and a partial region of the through opening, on the upper or lower surface of the substrate. An insulating stress relaxation layer is added between the fuel layer and the fuel electrode layer.
[0019]
  The solid oxide fuel cell of the present invention is as described above.Of the present inventionA solid oxide fuel cell using a fuel cell stack,
  It is characterized in that the cell plate assembly composed of the pair of cell plates and separators having flow paths are alternately laminated.
[0020]
  Furthermore, another solid oxide fuel cell of the present invention is as described above.Of the present inventionA solid oxide fuel cell using a fuel cell stack,
  An electrical insulating layer is interposed between the cell plate assembly composed of the pair of cell plates and the adjacent cell plate assembly.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the stack for a solid oxide fuel cell and the solid oxide fuel cell of the present invention will be described in detail. In the present specification, “%” indicates a mass percentage unless otherwise specified.
For convenience of explanation, one surface of each layer such as a substrate or an electrode layer is a “front surface” or “upper surface”, and the other surface is a “back surface” or “lower surface”. The electrode layer such as “surface electrode” or “upper electrode”, “back electrode” or “lower electrode” is described as an equivalent element, and a configuration in which the electrode layers are replaced with each other is also included in the scope of the present invention. It is.
[0022]
As described above, the fuel cell stack of the present invention has a structure in which the solid electrolyte layer is sandwiched between the air electrode layer and the fuel electrode layer, that is, the air electrode layer-solid electrolyte layer-fuel electrode layer, or the stacking order thereof is reversed. The cell plate having a laminated structure of fuel electrode layer-solid electrolyte layer-air electrode layer, which is an embodiment, is used.
[0023]
  here,Of the present inventionIn the stack, a concave groove is formed in a substrate that functions as a support of the laminated structure, and an electrode layer, a solid electrolyte layer, and an electrode layer are sequentially laminated on the substrate with the concave groove, and the layer of the substrate is laminated on these layers. The shape of the groove is substantially transferred, and the groove is formed in the electrode layer located on the outermost surface, that is, the fuel electrode layer or the air electrode layer to form a cell plate.
  Then, at least one pair of such cell plates is prepared, both cell plates are joined so that the concave grooves of both cell plates are opposed to each other, and a cell plate set is obtained. Stack to form a stack. As a result, in the cell plate assembly, tubular grooves are formed by the concave grooves, and the tubular grooves are formed by the fuel electrode layers or the air electrode layers, and the polarities are the same. No problem occurs even if the fuel gas channel or the air gas channel is used.
[0024]
  The present inventionNoThe tack uses the configuration as described above, and does not require a separator as an essential component. In the present invention, it is possible to form a cell plate that is lighter, thinner, and shorter than conventional cell plates by applying semiconductor integrated technology as will be described later. A substrate having a penetrating opening (a substrate with an opening) can also be used, and these points are also different from the above-mentioned JP-A-9-45355.
[0025]
  on the other hand,referenceThe stack has a groove formed in one or both of the air electrode layer and the fuel electrode layer, and the electrode layer not located on the outermost surface also has a function as a support. For the formation of tubular grooves and lamination of cell plate assemblies, etc.Of the present inventionThe same as in the case of stack.
[0026]
As described above, in the stack and the solid oxide fuel cell according to the present invention, one of the fuel gas and the air, for example, the fuel gas flows through a tubular path formed by joining the grooved cell plates. And separated from the air by the solid electrolyte layer. As a result, the fuel gas is configured to flow through the tubular flow path sealed with the fuel electrode layer and the solid electrolyte layer, so that it is exposed to both the fuel gas and the air, and high temperature durability is required for both gases. It can be set as the structure which does not require a separator.
[0027]
In the present invention, the cross-sectional shape of the concave groove of the cell plate is not particularly limited as long as it can form a tubular flow path when the two concave grooves are joined. A shape obtained by appropriately dividing a rectangle and a polygon, typically a semicircular shape, a semi-elliptical shape, a rectangular shape or a half shape of a polygon can be used.
In addition, when joining the electrode layers of each cell plate with the concave grooves of the two cell plates facing each other, the purpose of functioning as a bonding material or the purpose of assisting the current collecting function of the electrode layer, mechanical thermal stress In order to alleviate this, an intermediate layer can be formed and laminated in a part between two electrode layers.
[0028]
In the present invention, it is possible to use a porous substrate as the substrate of the cell plate. In this case, the substrate has a function of maintaining the strength of the cell plate, and forms an electrode layer or a solid electrolyte layer. In addition to fulfilling the function as the support substrate, it can also function as a gas flow path for flowing air when the fuel gas flows through the tubular flow path, for example, a gas that does not flow through the tubular flow path.
In this case, it is possible to form a stack having a high lamination density in which only the cell plate assembly is laminated without using the separator plate in which the flow path is formed. Moreover, when this porous substrate is electrically conductive, it is also possible to have a function of collecting current generated by the cell.
Furthermore, in order to adjust the generated voltage to the required power generation value, an electrical insulating layer can be inserted between adjacent cell plate assemblies and stacked, and the cell plate assemblies can be electrically connected in series.
In this case, since the same kind of gas flows on both surfaces of the electrical insulating layer, a separator that also requires durability against both gases is not required.
[0029]
On the other hand, if the substrate of the cell plate is porous and allows gas to pass through but has insufficient function as a gas flow path, or if a gas impermeable substrate with an opening is used, the cell plate strength It is excellent in the function which hold | maintains, and the function which supports an electrode layer or a solid electrolyte layer film | membrane. In particular, there is an advantage that it is easy to form a solid electrolyte layer functioning as a gas partition in a dense and thin film. Furthermore, there is an advantage that the substrate is excellent in the function of transferring the heat energy heated at the time of startup.
[0030]
When a stack is formed using such a substrate having gas impermeability or an opening, a pair of cell plates (cell plate assembly) and a separator having a gas flow path can be alternately stacked.
That is, one separator is stacked for every two cell plates, and the stacking density of the portion having the power generation function can be improved as compared with the conventional configuration in which the separator is inserted for each cell plate. .
When both sides of the separator in the stacking direction are electrically insulated, the upper cell plate assembly and the lower cell plate assembly can be electrically insulated, and the cell plates are electrically connected in series. It becomes possible. For example, the separator can be formed of insulating ceramics or the like, or can be formed by insulating the surface that is bonded or in contact with at least one cell plate of a metallic separator.
[0031]
  Furthermore, as mentioned above,referenceIn the stack, one of the air electrode and the fuel electrode layer can serve as the cell plate substrate.
  For the purpose of assisting the function of the gas flow path and for the purpose of controlling the generated voltage, a stack configuration in which a separator and an electrically insulating gas-impermeable layer are inserted into each of the two cell plate assemblies can be used.
[0032]
Next, the materials of the solid electrolyte layer and the electrode layer in the stack and the solid oxide fuel cell of the present invention and the production methods thereof will be described.
In the present invention, materials for the solid electrolyte layer and the electrode layer are not particularly limited, and known materials can be used for each. For example, as the fuel electrode material, known nickel, nickel cermet, platinum and the like can be used. As an air electrode, for example, La_1-xSr_xMnO₃, La_1-xSr_xCoO₃Perovskite type oxides such as can be used.
On the other hand, as the solid electrolyte layer, known Nd₂O₃, Sm₂O₃, Y₂O₃And Gd₂O₃Stabilized zirconia and CeO₂-Based solid solution, bismuth oxide and LaGaO₃Etc. can be used.
[0033]
In addition, as a method for forming a solid electrolyte layer or an electrode layer, a film forming method such as a known EVD method, thermal spraying method, sputtering method or vapor deposition method, a tape casting method, a dipping method, a sol-gel method, a coating method, a spray method, or the like Can be applied.
When one of the electrode layers is used as a substrate, the raw material powder formed by a known powder metallurgy technique is formed into a desired grooved substrate by an extrusion method or the like, and sintered to form a substrate with a groove. A cum electrode layer can be manufactured.
[0034]
Furthermore, as described above, the porous substrate can be used in the present invention, but as the porous substrate, a porous metal or ceramic having gas permeability can be used. For example, stabilized ZrO to which 15 mol of known CaO is added₂And Al₂O₃Ceramic sintered bodies such as Ni, Ni alloys, SUS, and Fe alloys can be used, and sintered alloys and sintered cermets can be used.
A porous substrate with a concave groove can also be manufactured by a known manufacturing method. For example, it can be manufactured by a method of extruding into a desired shape and then firing, or a method of manufacturing a known foam metal.
Furthermore, the porous substrate is a layer having a relatively high porosity that mainly functions as a gas flow path, and a relatively porous layer that mainly functions as a support substrate when forming an electrode layer or a solid electrolyte layer. It can also be a substrate formed of at least two layers with a low rate layer.
[0035]
Furthermore, in the substrate having an opening used in the present invention, a concave groove is formed on at least one of the upper surface and the lower surface of the substrate, and an opening penetrating from the upper surface of the substrate to the lower surface is formed in a part of the concave groove. Which can be used either gas permeable or impermeable. For example, quartz, refractory glass, alumina, magnesia, partially stabilized zirconia, silicon, Ni, Ni-based alloy, SUS, and Fe-based alloy can be used.
[0036]
When the substrate is electrically conductive, a portion other than the substrate opening or the substrate for the purpose of electrically insulating the substrate and one of the electrodes or for reducing the thermal stress between the substrate and the solid electrolyte layer or the electrode layer An electrical insulation / thermal stress relaxation layer may be formed on at least one side of a part of the opening.
In this case, for example, containing silicon oxide, silicon nitride, phosphosilicate glass (PSG), phosphoborosilicate glass (BPSG), alumina, titania, zirconia, ceria or MgO and any mixture thereof, preferably these A material having a main component can be used. Moreover, the metal which has silicon, titanium, chromium, iron, cobalt, nickel, zirconium, molybdenum, tungsten, or tantalum, and these mixed metals as a main component can be used.
[0037]
【Example】
Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited to these examples.
[0038]
(Reference example 1)
  In FIG.This exampleThe manufacturing process of the cell board used in is shown.
  The porous substrate 1 was produced on the mold 5 having a convex portion according to a known method for producing a porous metal body. That is, a mixture composed mainly of Ni raw material powder having an average particle size of 0.5 to 5 μm together with an organic solvent, a water-soluble resin binder, a surfactant, a plasticizer and water is applied onto the convex mold 5 by the doctor blade method. To form a surface layer having a relatively low porosity, and then changing the mixing ratio of the organic solvent, water-soluble resin binder and surfactant in the raw material mixture to form a substrate layer having a relatively high porosity in the same manner. A molded body was formed by overlapping.
  Furthermore, a heat treatment comprising a bubble forming process, a degreasing process, and a sintering process is performed, and the surface layer 1a having a porosity of 20% and a film thickness of 10 μm is relatively low, and the film thickness is 80% and the film thickness is the thinnest part. A porous substrate 1 composed of a porous substrate layer 1b having a concave groove of 500 μm was formed.
[0039]
Next, the fuel electrode layer 2, the electrolyte layer 3, and the air electrode layer 4 were formed on the concave groove surface side of the substrate 1 by a known sputtering method. That is, the substrate 1 is set in an RF magnetron sputtering apparatus, and the substrate is first cleaned with an Ar ion beam for 5 minutes by a reverse sputtering method, followed by RF output using a target of Ni and yttria stabilized zirconia cermet. A film thickness of 5 μm was formed under the conditions of 300 W and a film forming pressure of 5 Pa. Next, the target was replaced with yttria-stabilized zirconia, and a film having a thickness of 2 μm was formed under the conditions of an RF output of 300 W and a pressure of 1 Pa. Further, the target was replaced with LSM, and a cell plate 6 was formed by forming a film of 5 μm under the conditions of an RF output of 300 W and a film forming pressure of 5 Pa.
[0040]
  next,This exampleThe stack was created as shown in FIG.
  Two cell plates 6 are laminated so that the concave grooves are opposed to each other (a and b), and a bonding layer 7 in which an Ag-based brazing material capable of low-temperature baking is applied to both sides of the ribbon-shaped Pt line on portions other than the concave grooves. Were inserted, laminated, and fired at 900 ° C. to form a cell plate assembly 8. A SUS gas introduction pipe 9 was inserted into the tubular gas flow path formed by the concave grooves of the two cell plates 6 and baked at the same time (c).
  Next, SUS end plates 10 having a thickness of 1 mm are installed at both ends of the three stacked cell plate assemblies 8, and the SUS end plates 10 are mechanically fastened with bolts (not shown) to form a stack. 11 was formed (d).
[0041]
About the obtained stack 11, air is introduced into a tubular flow path (X direction) formed by the cell plate assembly 8 and provided with a SUS gas introduction pipe (not shown), and a direction perpendicular to this (Y direction) ), Fuel hydrogen gas was introduced into the porous substrate 1 and the power generation characteristics were evaluated at 600 ° C. (e). 0.1 W / cm for cell effective area²Was able to generate electricity.
As shown in FIG. 2 (e), in the XY cross section, the cell plate laminated cross sectional area for introducing the fuel is limited, or the portion where the SUS gas introduction pipe is connected has a relatively low temperature and is abrupt. The stack temperature can be adjusted so that thermal stress is hardly applied to the temperature rise.
[0042]
  Like the aboveThis exampleAccording to the stack, since one gas can be introduced into the tubular flow path formed by the cell plate assembly, the gas sealing property of the gas introduction part is improved and it is durable against high temperature or thermal shock. The advantage that the property is improved is obtained.
  In addition, since a separator that is exposed to both fuel gas and air, which is one cause for reducing durability, is not used, it is possible to obtain a solid oxide fuel cell with improved high-temperature durability.
  Furthermore, since no separator is used, the number of stacked cell plates can be increased per unit length in the Z direction in FIG. As a result, the power density per stack capacity can be improved, and a small-sized fuel cell with excellent startability can be manufactured.
[0043]
(Example1)
  A manufacturing process of the cell plate used in this embodiment will be described with reference to FIG. FIG. 3 is a partial cross-sectional view and a plan view of the cell plate in each manufacturing process.
  First, as shown in FIG. 3, an insulating stress relaxation layer 22, such as a silicon nitride film, was formed on both sides of the Si substrate 21 by a low pressure CVD method (a).
  Next, a desired region of the silicon nitride film 22 on the back surface of the substrate is formed by photolithography and CF.₄The silicon etching port 26 was formed by removing by chemical dry etching using gas (b).
  Next, silicon etching is performed using a silicon etching solution, for example, hydrazine at a temperature of about 80 ° C. to form a substrate opening 27 between the front and back surfaces of the Si substrate 21 and a diaphragm 29 of the silicon nitride film 22 ( c).
  Next, an electrolyte film 23 such as YSZ (yttria stabilized zirconia), for example, was formed in a 1.5 cm square region with a thickness of about 2 μm so as to cover the diaphragm 29 using an evaporation mask by RF sputtering (d).
[0044]
Then again as shown in FIG.₄Etching was performed from the back surface of the Si substrate by chemical dry etching using gas to remove the silicon nitride film diaphragm 28 in contact with the back surface of the electrolyte film 23, thereby exposing the back surface of the electrolyte film 23. At the same time, the silicon nitride film on the back surface of the Si substrate 21 was also removed (e).
Next, LSM was deposited on the Si substrate surface to a thickness of about 500 nm in a 1.8 cm square region so as to cover the region where the electrolyte film 23 was formed using the vapor deposition mask by RF sputtering, and the lower electrode layer 24 was formed (f ).
Next, an Ni film is formed to a thickness of about 500 nm from the back surface of the Si substrate 21 by using the EB vapor deposition method, and the upper electrode 25 that directly contacts the back surface of the electrolyte film 23 is formed. (G).
[0045]
The obtained two cell plates 29 were laminated so that the concave grooves 25g formed by substrate etching face each other as shown in FIG. The cell plate set 29P and the separator 30 made of insulating ceramics and having a flow path formed thereon were alternately stacked 10 layers at a time to form a stack of this example (a).
An electric wiring diagram of the obtained stack is shown in FIG. 5B, and a perspective view is shown in FIG.
About this stack, the fuel H is added to the tubular flow path formed by the cell plate groove.₂Gas and air were introduced into the side of the separator, and the power generation characteristics were evaluated at 700 ° C. It was possible to obtain 11V as the power generation voltage of the stack.
[0046]
As described above, according to the stack of the present embodiment, since one gas can be introduced into the tubular flow path formed by the cell plate assembly, the gas sealing property is improved and the durability is excellent. A stack can be formed.
In addition, compared with a stack having a configuration in which conventional cell plates and separators are alternately stacked, in this embodiment, a configuration in which two cell plates and one separator are alternately stacked can be used. A fuel cell having a high density can be manufactured.
Furthermore, in this embodiment, the separator is not exposed to both fuel and air at high temperatures, so that a fuel cell having excellent durability can be obtained.
[0047]
In addition, by stacking electrically insulating separators, it is possible to connect cell plate assemblies in electrical series, and it is easy to perform high-voltage power generation according to power generation requirements. In addition, since the cell plate having a high substrate density and good planarity can be used, it is possible to form a thinner and more dense electrolyte layer, thereby reducing power generation loss. Therefore, it is possible to manufacture a fuel cell having a high output density, a small size, and improved startability.
When using a gas-impermeable substrate, gas separation is possible without forming an electrolyte layer on the entire surface of the substrate. The effect which can be reduced is acquired.
[0048]
As a modification of the present embodiment, the configuration of the cell plate can be as shown in FIG.
That is, an insulating stress relaxation layer formed on one surface of the substrate is used for the structure in which the electrolyte layer is formed from the surface of the substrate where the groove is formed or for the purpose of increasing the groove by increasing the strength of the electrolyte layer. A configuration in which the layer is reinforced can be employed.
[0049]
(Reference example 2)
  In this exampleThe manufacturing process of the cell plate to be used will be described with reference to FIG.
  Reference example1 was used to form a sintered body of the air electrode layer substrate 34 by a known tape casting method and coating method. A mixture containing LSM having a raw material average particle size of 0.5 to 1 μm was tape-cast on a mold 35 and fired in the atmosphere at 1200 ° C. The film thickness was 200 μm at the thinnest portion of the concave portion and the porosity was 20%.
  In the same manner as in Example 1, the electrolyte layer 33 and the fuel electrode layer 32 were formed on the concave groove side to manufacture the cell plate 36.
  The obtained two cell plates 36 were laminated so as to face each other to form a cell plate assembly 37, and the cell plate assembly 37 and the separator 38 were alternately laminated to form a stack 39.
  Example1When the power generation characteristics were evaluated in the same manner as described above, 0.15 W / cm²was gotten.
[0050]
According to the present embodiment, two cell plates having an air electrode substrate 34 that also has a concave groove and also serves as a substrate are laminated so as to form a tubular flow path, whereby a tube-type cell that is resistant to thermal shock. A stack can be constructed that is similar to the stack in which
On the other hand, it has the outstanding advantage that the manufacturing process according to the manufacturing method of the flat plate type which is simple and excellent in mass productivity can be adopted.
[0051]
(Reference example 3)
  Reference exampleThe cell plate assembly manufactured in the same manner as 1 is laminated with 10 layers of alumina insulating flat plates alternately,This example(Fig. 8).
  Reference exampleThe power generation characteristics were evaluated in the same manner as in Example 1, and 8 V was obtained as the power generation voltage.
  in this way,This exampleWith this cell plate and stack structure, it is possible to produce a small solid oxide fuel cell that can generate high voltage power and has a high cell plate stacking density.
[0052]
  Although the present invention has been described in detail with some preferred embodiments, the present invention is not limited to these embodiments, and various modifications are possible within the scope of the gist of the present invention.
  For example,Of the present inventionFor the cell plate related to the stack, a cell plate having a groove on only one of the front surface and the back surface (upper surface or lower surface) was used, but the present invention is not limited to this. With cell plate havingOf the present inventionIt is also possible to form a stack.
[0053]
【The invention's effect】
As described above, according to the present invention, a specific shape is imparted to an electrode layer or the like using a predetermined substrate, or a lamination specification of each layer is appropriately selected. Providing a stack for a solid oxide fuel cell that can reduce resistance, secure a sufficient electrode reaction area, and is highly reliable for usage that frequently starts and stops, and a solid oxide fuel cell using the same can do.
See separate bullet
[Brief description of the drawings]
[Figure 1]An example of a stack for a solid oxide fuel cellIt is sectional explanatory drawing which shows the manufacturing process of the cell board used for.
2 is a cross-sectional and perspective view showing a stack using the cell plate shown in FIG. 1. FIG.
Fig. 3 Stack of the present inventionThe fruitIt is a partial cross section and plane explanatory drawing which show the manufacturing process of the cell board used for an Example.
FIG. 4 Stack of the present inventionThe fruitIt is a partial cross section and plane explanatory drawing which show the manufacturing process of the cell board used for an Example.
5 is a cross-sectional view, wiring, and perspective view showing a stack using the cell plate shown in FIG. 4. FIG.
6 is a partial cross-sectional view showing a modified example of the cell plate shown in FIG. 4;
[Fig. 7]Other examples of stacksIt is sectional drawing which shows the manufacturing process of the cell board used for and a stack using the same.
[Fig. 8]Other examples of stacksFIG.
[Explanation of symbols]
    1,21 substrate
    1a Substrate surface layer
    1b Substrate layer
    2, 32 Fuel electrode layer
    3, 33 Electrolyte layer
    4, 34 Air electrode layer
    5, 35 type
    6, 36 cell plate
    7 Bonding layer
    8 cell board assembly
    9 Gas introduction pipe
  10 End plate
  11, 39 stacks
  22 Insulation stress relaxation layer
  23 Electrolyte layer
  24 Lower electrode layer
  25 Upper electrode layer
  25g groove
  26 Etching port
  27 opening
  28 Diaphragm
  29 Cell plate
  29P cell board assembly
  30, 38 Separator
  37 cell board assembly

Claims (9)

In a stack for a solid oxide fuel cell, which is formed by laminating a cell plate sandwiching an air electrode layer and a fuel electrode layer on a solid electrolyte layer,
The cell plate has a substrate having a groove on the upper surface and / or the lower surface, and a fuel electrode layer, a solid electrolyte layer and an air electrode layer, or an air electrode layer, a solid electrolyte layer and a fuel electrode on the substrate surface on the groove side. These layers laminated in order of layers and substantially transferring the shape of the groove,
A penetrating opening is partially formed at the bottom of the concave groove, and the fuel electrode layer or the air electrode layer protrudes from the opening,
At least one pair of the cell plates is laminated so that the fuel electrode layers or the air electrode layers are opposed to each other ,
Tubular groove formed by the junction between the fuel electrode layer or between the air electrode layer is, that acts as a gas flow path for fuel or air, a solid oxide fuel cell stack, characterized in that.   2. The solid oxide fuel cell stack according to claim 1, wherein the substrate is made of a porous material and functions as a gas channel having a polarity opposite to that of a gas channel handled by the tubular groove. The solid electrolyte layer and the air electrode layer or the fuel electrode layer are laminated so as to close the through opening from the substrate surface opposite to the groove side, and the fuel electrode layer or the air electrode layer is on the groove side. Layered from the substrate surface,
The cross section of the through-opening has a stacked structure of a fuel electrode layer-solid electrolyte layer-air electrode layer or an air electrode layer-solid electrolyte layer-fuel electrode layer in order from the substrate surface on the concave groove side. The solid oxide fuel cell stack according to claim 1 . The air electrode layer or the fuel electrode layer is laminated so as to close the through opening from the substrate surface opposite to the groove side, and the fuel electrode layer or air electrode layer and the solid electrolyte layer are on the groove side. Layered from the substrate surface,
The cross section of the through-opening has a stacked structure of a fuel electrode layer-solid electrolyte layer-air electrode layer or an air electrode layer-solid electrolyte layer-fuel electrode layer in order from the substrate surface on the concave groove side. The solid oxide fuel cell stack according to claim 1 . Insulating stress relaxation between the substrate and the air electrode layer or the fuel electrode layer in a region other than the through-opening portion on the upper surface or the lower surface of the substrate, or in this region and a partial region of the through-opening portion. The stack for a solid oxide fuel cell according to any one of claims 1 to 4 , further comprising a layer. Substrate made of the porous material, in its cross-section, any one of claims 1 to 5, the porosity of the substrate surface near the groove side, characterized in that it is formed lower than the porosity in the substrate The stack for a solid oxide fuel cell according to one item. A solid oxide fuel cell comprising the fuel cell stack according to any one of claims 1 to 6 ,
A solid oxide fuel cell, wherein the cell plate assembly comprising the pair of cell plates and a separator having a flow path are alternately laminated. A solid oxide fuel cell comprising the fuel cell stack according to any one of claims 1 to 6 ,
A solid oxide fuel cell, wherein an electrical insulating layer is interposed between a cell plate assembly comprising the pair of cell plates and an adjacent cell plate assembly. A solid oxide fuel cell comprising the fuel cell stack according to any one of claims 1 to 6 ,
A solid oxide fuel cell, wherein a separator and an electrically insulating layer are interposed between a cell plate assembly composed of a pair of cell plates and an adjacent cell plate assembly.

Images