JP2009245654A - Manufacturing method for solid oxide fuel cell, and the solid oxide fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a solid oxide fuel cell capable of preventing warpages, when sintering together an electrolyte green sheet and an electrode green sheet, including a material of a fuel electrode or an air electrode and improving reliability at making of a fuel cell stack. <P>SOLUTION: At least one of electrolyte green sheets 2a, 2b containing an electrolyte material and having a through-hole 7 on at least a part of the electrolyte green sheet and having a gas-permeating zone in the thickness direction, is arranged on at least one of the electrode green sheets 1 containing one electrode material of a fuel electrode or an air electrode; the electrode green sheet is bent so as to make it laminated in two layers or more by at least one crease; and a laminate, wherein the gas-permeating zone is arranged on one surface is formed, by holding the bent electrode green sheet between the electrolyte green sheets; an electrolyte and one electrode are formed by sintering the laminate; and the other electrode 41 is formed on the electrolyte on the surface, where the gas-permeating zone is not formed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a solid oxide fuel cell and a solid oxide fuel cell.

  A fuel cell is a cell that can directly convert chemical energy generated when fuel is oxidized into electric energy while continuously supplying fuel from the outside and exhausting combustion products. The types of fuel cells are classified according to the electrolyte, and those using metal oxides having ion conductivity for the electrolyte are called solid oxide fuel cells. Various types of solid oxide fuel cells have been proposed. For example, Patent Document 1 discloses a fuel electrode (anode), an electrolyte, and an air electrode (cathode) on both surfaces of an electrolyte layer. A stacked unit cell is disclosed.

By the way, in order to produce the above single cell, there is a method of laminating sheets called so-called ceramic green sheets and sintering them. For example, when an electrolyte green sheet containing an electrolyte material and a fuel electrode green sheet containing a fuel electrode material are laminated and co-sintered, a laminate of an electrolyte and a fuel electrode is formed. And if an air electrode is formed in the surface on the opposite side to the surface in which the fuel electrode is formed in electrolyte, a solid oxide fuel cell will be obtained.
JP 2006-339034 A

  By the way, the electrolyte green sheet and the fuel electrode green sheet have different coefficients of thermal expansion, so that there is a problem that warping occurs when they are co-sintered. As a result, when plate-like separators and interconnectors are stacked and stacked, a load is applied to a part of the cells, cell destruction occurs, and gas sealing becomes difficult.

  Therefore, the present invention has been made to solve the above-described problem, and can prevent warping when co-sintering an electrolyte green sheet and an electrode green sheet containing a fuel electrode or an air electrode material. An object of the present invention is to provide a method for manufacturing a solid oxide fuel cell and a solid oxide fuel cell, which can prevent cell breakage in stacking and improve reliability and yield.

  The method for producing a solid oxide fuel cell according to the present invention has been made in order to solve the above problem, and includes at least one electrode green sheet containing an electrode material of either a fuel electrode or an air electrode. A step of disposing at least one electrolyte green sheet containing an electrolyte material and having a gas permeable region in the thickness direction in at least a part of the region; and at least one of the electrode green sheets A folded body in which two or more layers are folded at a crease, the folded electrode green sheet is sandwiched from both sides by the electrolyte green sheet, and the gas permeable region is arranged on one side A step of forming the sintered body, forming an electrolyte and one electrode, and the gas permeable region in the laminated body. Forming the other electrode on the electrolyte on the surface on which no is formed.

  According to the manufacturing method, one electrode and the electrolyte green sheet are bent, and the laminate is formed so that the electrode green sheet is sandwiched by the electrolyte green sheet from both sides. That is, since the electrode green sheet is sandwiched by the same material, when co-sintering is performed, the warp generated on one surface of the electrode green sheet is caused by the warp generated on the other surface. As a result, the occurrence of warpage can be prevented as a whole. Therefore, the reliability in stacking can be improved and the yield can be improved. Each green sheet can be used by stacking one by one, but can also be used in a state where a plurality of green sheets are stacked. For example, a plurality of electrode green sheets can be laminated, and a plurality of electrolyte green sheets can be laminated thereon, and adjusted so as to have a predetermined film thickness, thereby forming the laminate.

  In the above manufacturing method, the electrolyte green sheet can be formed of one sheet, but can be formed of two sheets. In this case, a gas permeable region can be formed in one sheet. it can.

  Moreover, although the area | region which can permeate | transmit a gas can be made into various aspects, it can be comprised, for example by forming a some through-hole in an electrolyte green sheet. At this time, the through-hole can be a mesh-like region composed of a large number of small holes. Thus, the gas permeable region can be formed, for example, such that the electrode green sheet is exposed through a through hole or the like.

  In addition, a solid oxide fuel cell according to the present invention is made to solve the above-described problem, and includes a flat first electrolyte and a flat shape disposed on one surface of the first electrolyte. A flat air electrode disposed on the other surface of the first electrolyte, a flat air electrode disposed on the fuel electrode or the air electrode, and formed with a gas permeable region in the thickness direction. 2 electrolytes.

  According to this configuration, since the electrode of the fuel electrode or the air electrode is sandwiched between the first and second electrolytes, if any one electrode is sandwiched between the electrolytes at the time of manufacture, the warp will occur. Can be prevented. As a result, cell breakage in stacking can be prevented, and reliability and yield can be improved. In addition, although flat shape means shapes with small thickness, such as a sheet form and a thin film form, it will not necessarily be restricted if it is a shape with thickness smaller than the length of the width direction. For this battery, power is generated by supplying a fuel gas such as a hydrocarbon-based gas to the fuel electrode and an oxidant gas such as air to the air electrode, but a mixed gas can also be supplied. .

  The gas permeable region of the second electrolyte can take various forms, but can be formed by, for example, a plurality of through holes. As an example of a through-hole, it can form in the mesh form which consists of many small holes, for example.

  According to the present invention, when an electrolyte green sheet containing an electrolyte material and an electrode green sheet containing a fuel electrode or an air electrode material are co-sintered, warping can be prevented, and as a result, stacking can be performed. The reliability can be improved.

  An embodiment of a method for producing a solid oxide fuel cell according to the present invention will be described. The solid oxide fuel cell according to the present embodiment is configured by arranging a sheet-like fuel electrode and an air electrode on both surfaces of a sheet-like electrolyte. The member constituting the battery is mainly formed of a green sheet. Initially, the material which comprises each member is demonstrated.

  First, the electrolyte, fuel electrode, and air electrode used in this embodiment can be formed of a ceramic powder material. The average particle size of the powder used at this time is preferably 10 nm to 100 μm, more preferably 50 nm to 50 μm, and particularly preferably 100 nm to 10 μm. In addition, an average particle diameter can be measured according to JISZ8901, for example. Hereinafter, each member will be described in detail.

(Electrolytes)
As the electrolyte material, those known as electrolytes for solid oxide fuel cells can be used. For example, ceria oxide (GDC) doped with samarium or gadolinium, lanthanum doped with strontium or magnesium, An oxygen ion conductive ceramic material such as a galide oxide, zirconia oxide (YSZ) containing scandium or yttrium can be used.

(Fuel electrode)
As the fuel electrode, for example, a mixture of a metal catalyst and a ceramic powder material made of an oxide ion conductor can be used. As the metal catalyst used at this time, a material that is stable in a reducing atmosphere, such as nickel, iron, cobalt, or a noble metal (platinum, ruthenium, palladium, etc.) and has hydrogen oxidation activity can be used. In addition, as the oxide ion conductor, one having a fluorite structure or a perovskite structure can be preferably used. Examples of those having a fluorite structure include ceria-based oxides doped with samarium, gadolinium, and the like, and zirconia-based oxides containing scandium and yttrium. In addition, examples of those having a perovskite structure include lanthanum galide oxides doped with strontium and magnesium. Among the above materials, it is preferable to form the fuel electrode with a mixture of an oxide ion conductor and nickel. The mixed form of the ceramic material made of the oxide ion conductor and nickel may be a physical mixed form, or may be a powder modification to nickel or a nickel modification to ceramic material. Good. Moreover, the ceramic material mentioned above can be used individually by 1 type or in mixture of 2 or more types. The fuel electrode 2 can also be configured using a metal catalyst alone.

(Air electrode)
The ceramic powder material that forms the air electrode may have the same particle size as that of the fuel electrode. As the ceramic powder material, for example, a metal oxide made of Co, Fe, Ni, Cr, Mn or the like having a perovskite structure or the like can be used. Specifically, (Sm, Sr) CoO ₃ , (La, Sr) MnO ₃ , (La, Sr) CoO ₃ , (La, Sr) (Fe, Co) O ₃ , (La, Sr) (Fe, Co , Ni) O _{3 and the} like, and (La, Sr) (Fe, Co) O ₃ is preferable. The ceramic material mentioned above can be used individually by 1 type or in mixture of 2 or more types.

(Formation method)
And these electrolyte, fuel electrode, and air electrode can be formed on the sheet | seat used as a base material by the doctor blade method, for example. At that time, these electrolyte, fuel electrode, and air electrode need to be made into a paste, and are formed by adding appropriate amounts of binder resin, plasticizer, dispersant, organic solvent, etc., with the above-mentioned materials as the main components. The More specifically, in mixing the main component and the binder resin, it is preferable to add a binder resin or the like so that the main component is 20 to 90% by weight, preferably 40 to 60% by weight. If the paste thus formed is dried at a predetermined temperature for a predetermined time on the base sheet, a green sheet is completed.

(Battery manufacturing method)
Hereinafter, a method for manufacturing a solid oxide fuel cell according to the present embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing a method for manufacturing the first solid oxide fuel cell according to the present embodiment. Here, a fuel cell is manufactured using an electrolyte, a fuel electrode, and an air electrode green sheet each containing an electrolyte material, a fuel electrode material, and an air electrode material.

  First, as shown in FIG. 1 (a), first and second electrolyte green sheets 2a and 2b are arranged at two positions on a fuel electrode green sheet 1 at a predetermined interval. Here, the green sheets 1, 2a, 2b can be stacked one by one, but a plurality of sheets can be stacked to have a predetermined film thickness. At this time, it arrange | positions so that one edge part of each electrolyte green sheet 2a, 2b may each correspond with the both right-and-left both ends of the fuel electrode green sheet | seat 1. FIG. A plurality of through holes 7 are formed in the second electrolyte green sheet 2b. Next, as shown in FIG. 1B, the fuel electrode green sheet 1 is folded in half and pressed to form the laminate 3. At this time, the crease is formed in the gap between the two electrolyte green sheets 2a and 2b. In this laminate 3, the fuel electrode green sheet 1 is folded in half, and the electrolyte green sheets 2a and 2b are arranged so as to sandwich the fuel electrode green sheet 1 from both sides. Subsequently, the laminate 3 is sintered at a known condition, for example, at about 1450 ° C. for about 1 hour. Thus, the first and second electrolytes 21a and 21b and the fuel electrode 11 are formed. Subsequently, as shown in FIG. 1 (c), an air electrode green sheet is disposed on the first electrolyte 21a disposed on the upper surface of the multilayer body 3, and a known condition, for example, about 1 at about 1000 ° C. The air electrode 4 is formed by time sintering. The fuel cell is completed through the above steps.

  Note that a current collector that collects current from the fuel electrode 11 can be formed on the second electrolyte 21b, for example, as shown in FIG. The current collector 8 needs to be formed with a plurality of through holes so as to be porous or have a gas permeable flow region so as not to disturb the gas permeability of the second electrolyte 21b. The current collector 8 can be made of, for example, a conductive metal such as Fe, Ti, Cr, Cu, Ni, Ag, Au, or Pt. A paste that is used alone or a mixture of two or more is used. The paste is filled in the through hole 7 of the second electrolyte 21 b so as to come into contact with the fuel electrode 11. Thereafter, it is dried under known conditions and used as a current collector. Further, as shown in FIG. 1 (d), a similar current collector 8 can be formed on the air electrode 4.

  As described above, according to the present embodiment, the fuel electrode green sheet 1 is bent, and the fuel electrode green sheet 1 is sandwiched by the first and second electrolyte green sheets 2a and 2b from both sides. 3 is formed. That is, since the fuel electrode green sheet 1 is sandwiched between the same materials, the warpage that occurs in the fuel electrode green sheet 1 and the first electrolyte green sheet 2a occurs when co-sintering is performed. It is offset by the warp generated between the two electrolyte green sheets 2b, and the generation of the warp can be prevented as a whole. Therefore, the reliability at the time of stacking can be improved. Further, since the fuel electrode and the electrolyte can be sintered at the same time without requiring a holding plate or the like, the productivity can be improved.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, the formation method of the laminated body in the said embodiment is an illustration, and the other method is also possible. That is, it is only necessary to form a laminated body in which the fuel electrode green sheet is sandwiched between the electrolyte green sheets from both sides by folding the green sheet. At this time, as described above, instead of using the two electrolyte green sheets 2a and 2b, a single electrolyte green sheet may be used. In this case, the electrolyte green sheet may be formed with at least part of a gas permeable region such as a through hole, and the region may be disposed on any surface sandwiching the fuel electrode green sheet.

  Moreover, the penetration 7 formed in the 2nd electrolyte 21b can be formed, for example in mesh shape, and the magnitude | size of the mesh in this case can be made into # 100- # 150 grade, for example. In addition, the gas permeable region formed in the electrolyte may be provided by forming the electrolyte with a porous structure.

Moreover, in the said embodiment, although the laminated body 3 is formed with the fuel electrode green sheet 1 and the electrolyte green sheet 2, you may form a laminated body with an air electrode green sheet and an electrolyte green sheet. The method in this case is the same as that using the above-described fuel electrode green sheet.
In addition, as another method for forming the electrode after sintering the laminate, a green sheet may be used as described above, but it can also be manufactured by the following method.

  For example, in addition to the doctor blade method described above, as a wet coating method, for example, a screen printing method, an electrophoresis method, a doctor blade method, a dispenser coating method, a spray coating method, a dip coating method, or the like can be applied. Do the tie. In addition, it can be formed by a dry coating method. Examples of dry coating methods include vapor deposition, sputtering, ion plating, chemical vapor deposition (CVD), electrochemical vapor deposition, ion beam, laser ablation, atmospheric pressure plasma deposition, and reduced pressure. It can also be formed by a plasma film forming method or the like. If necessary, sintering is performed after coating to form another electrode.

It is a figure which shows 1st Embodiment of the manufacturing method of the solid oxide fuel cell which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel electrode green sheet 11 Fuel electrode 2a, 2b Electrolyte green sheet 21a, 21b Electrolyte 3 Laminated body 4 Air electrode green sheet 41 Air electrode 7 Through-hole

Claims (5)

At least one electrolyte containing an electrolyte material and having at least part of a gas-permeable region in the thickness direction on at least one electrode green sheet containing either the electrode material of the fuel electrode or the air electrode Placing a green sheet;
The electrode green sheet is folded so that two or more layers are laminated by at least one crease, and the folded electrode green sheet is sandwiched from both sides by the electrolyte green sheet, and the gas is permeable to one side. Forming a laminate in which regions are arranged;
Sintering the laminate to form an electrolyte and one electrode;
Forming the other electrode on the electrolyte on the surface where the gas permeable region is not formed in the laminate;
A method for producing a solid oxide fuel cell.   2. The method for producing a solid oxide fuel cell according to claim 1, wherein the electrolyte green sheet includes two sheets, and the gas permeable region is formed on one sheet.   The method for producing a solid oxide fuel cell according to claim 1 or 2, wherein the gas permeable region has a plurality of through holes formed in the electrolyte green sheet. A flat first electrolyte;
A flat fuel electrode disposed on one surface of the first electrolyte;
A flat air electrode disposed on the other surface of the first electrolyte;
A flat second electrolyte disposed on the fuel electrode or air electrode and formed with a gas permeable region in the thickness direction;
A solid oxide fuel cell. The solid oxide fuel cell according to claim 4, wherein the gas permeable region of the second electrolyte has a plurality of through holes.

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