JP5194943B2 - Method for producing solid oxide fuel cell and solid oxide fuel cell produced by this method - Google Patents

Description

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

  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. 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. A solid oxide fuel cell manufacturing method capable of preventing cell damage during stacking and improving reliability and yield can be provided, and a solid oxide fuel cell manufactured by this method For the purpose.

  The present invention has been made to solve the above-described problems, and at least one electrode material containing an electrolyte material is formed on at least one electrode green sheet containing the material of either the fuel electrode or the air electrode. Placing the electrolyte green sheet, folding the electrode green sheet so that two or more layers are laminated by at least one crease, and sandwiching the folded electrode green sheet from both sides Forming the laminate so as to sinter, laminating the laminate to form an electrolyte and one electrode, removing the electrolyte on one side of the laminate, and the laminate Forming the other electrode on the electrolyte on the other surface of the substrate.

  According to this configuration, one electrode and the electrolyte green sheet are bent, and the laminate is formed so that the electrode green sheet is sandwiched by one electrolyte 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 increased and the yield can be improved. Moreover, since one electrode and electrolyte can be sintered simultaneously, productivity can be improved.

  In the above manufacturing method, the step of removing the electrolyte on one side of the laminate and the step of forming the other electrode on the electrolyte on the other side of the laminate are preceded by any step. You may go. The other electrode can be obtained by, for example, laminating green sheets or forming them by printing and then sintering. In addition, each green sheet can be used by stacking one sheet at a time, but can also be used in a state where a plurality of 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.

  The laminate as described above can be formed by various methods. For example, by making the electrode green sheet approximately the same size as the electrolyte green sheet and folding both the green sheets in two, a laminate can be formed so that the electrolyte green sheet is held between the electrode green sheets. .

  Alternatively, the electrolyte green sheet is disposed at two positions on the electrode green sheet, and the electrode green sheet is folded in two, thereby sandwiching the electrode green sheet obtained by folding the electrolyte green sheet disposed at the two positions. Thus, a laminate can also be formed.

  The present invention has been made to solve the above problems, and is manufactured by the above-described method for manufacturing a solid oxide fuel cell. This battery does not warp and can improve the reliability in stacking.

  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 the present 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, etc. 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, and 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, three manufacturing methods of the battery according to the present embodiment will be described. FIG. 1 is a diagram showing a method for producing a first solid oxide fuel cell according to the present embodiment, FIG. 2 is a diagram showing a second production method, and FIG. 3 is a diagram showing a third production method. is there. 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 Manufacturing Method First, as shown in FIG. 1A, an electrolyte green sheet 2 having the same size as this is disposed on a fuel electrode green sheet 1. Here, the green sheets 1 and 2 can be stacked one by one, but a plurality of green sheets can be stacked to have a predetermined film thickness. The same applies to the second and third manufacturing methods described later. Next, as shown in FIG.1 (b), this is folded in half and pressed to form a laminate. In this laminate 3, the fuel electrode green sheet 1 is folded in two, and the electrolyte green sheet 2 is disposed in a folded state so that the fuel electrode green sheet 1 is sandwiched from both sides. In addition, the electrolyte green sheet is arrange | positioned in the part of a crease | fold so that a crease | fold may be covered. Subsequently, the laminate is sintered at a known condition, for example, at about 1450 ° C. for about 1 hour. Thus, the electrolyte 21 and the fuel electrode 11 are formed. Following this, as shown in FIG. 1C, the electrolyte 21 disposed on the lower surface of the laminate 3 is removed by polishing. Thereafter, as shown in FIG. 1 (d), the air electrode green sheet 4 is disposed on the electrolyte 21 disposed on the upper surface of the laminate 3, and is sintered at a known condition, for example, about 1000 ° C. for about 1 hour. Form an air electrode. The fuel cell is completed through the above steps.

Second Manufacturing Method As shown in FIG. 2A, an electrolyte green sheet 2 having the same size as this is disposed on the fuel electrode green sheet 1. Next, as shown in FIG. 2B, this is folded at two folds and pressed. In other words, the laminated green sheets are bent so that the ends of the green sheets are in contact with each other, and in the cross-sectional shape, the laminated body 3 having a shape in which the electrolyte green sheet 2 covers the periphery of the fuel electrode green sheet 1 having two layers is formed. To do. Subsequently, the laminate is sintered at a known condition, for example, at about 1450 ° C. for about 1 hour. Thus, the electrolyte 21 and the fuel electrode 11 are formed. Following this, as shown in FIG. 2C, the electrolyte 21 disposed on the lower surface of the laminate 3 is removed by polishing. Thereafter, as shown in FIG. 2 (d), the air electrode green sheet 4 is disposed on the electrolyte 21 disposed on the upper surface of the laminate 3, and sintered at a known condition, for example, about 1000 ° C. for about 1 hour. . The fuel cell is completed through the above steps. In the first and second manufacturing methods, the electrolyte 21 disposed so as to cover the crease may be removed after sintering.

Third Manufacturing Method First, as shown in FIG. 3A, the electrolyte green sheets 2a and 2b are arranged on the fuel electrode green sheet 1 at two positions at a predetermined interval. One end of each electrolyte green sheet 2a, 2b is arranged so as to coincide with the left and right ends of the fuel electrode green sheet 1, respectively. Next, as shown in FIG. 3B, the fuel electrode green sheet 1 is folded in half and pressed to form a laminate. 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 electrolytes 21a and 21b and the fuel electrode 11 are formed. Following this, as shown in FIG. 3C, the electrolyte 21b disposed on the lower surface of the laminate 3 is removed by polishing. Thereafter, as shown in FIG. 3 (d), the air electrode green sheet 4 is placed on the electrolyte 21 placed on the upper surface of the laminate 3, and sintered at a known condition, for example, about 1000 ° C. for about 1 hour. Form an air electrode. The fuel cell is completed through the above steps.

  As described above, according to the present embodiment, at least the fuel electrode green sheet 1 of the fuel electrode green sheet 1 and the electrolyte green sheet 2 is bent, and the fuel electrode green sheet 1 is sandwiched by the electrolyte green sheet 2 from both sides. Thus, the laminate 3 is formed. That is, since the fuel electrode green sheet 1 is sandwiched by the same material, the warp that occurs between the fuel electrode green sheet 1 and the electrolyte green sheet 2 on one side when co-sintering is performed. However, it is offset by the warp generated between the electrolyte green sheet 2 on the other side, 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, 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 1 is sandwiched between the electrolyte green sheets 2 from both sides by folding the green sheet.

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 formation method or the like, and 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. It is a figure which shows 2nd Embodiment of the manufacturing method of the solid oxide fuel cell which concerns on this invention. It is a figure which shows 3rd 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 2 Electrolyte green sheet 21 Electrolyte 3 Laminated body 4 Air electrode

Claims (4)

Disposing at least one electrolyte green sheet containing an electrolyte material on at least one electrode green sheet containing an electrode material of either a fuel electrode or an air electrode;
Folding the electrode green sheet so that two or more layers are laminated with at least one crease, and forming the laminated body so that the electrolyte green sheet sandwiches the folded electrode green sheet from both sides;
Sintering the laminate to form an electrolyte and one electrode;
Removing the electrolyte on either side of the laminate;
Forming the other electrode on the electrolyte on the other surface of the laminate;
A method for producing a solid oxide fuel cell.   The electrode green sheet is the same size as the electrolyte green sheet, and the laminate is formed so that the electrode green sheet is sandwiched between the electrolyte green sheets by folding both green sheets in half. The method for producing a solid oxide fuel cell according to claim 1.   The electrolyte green sheet is disposed at two positions on the electrode green sheet at a predetermined interval, and the electrode green sheet is folded in two to thereby bend the electrolyte green sheet disposed at two positions. The method for producing a solid oxide fuel cell according to claim 1, wherein the laminate is formed so as to sandwich a sheet.   The solid oxide fuel cell manufactured by the manufacturing method of the solid oxide fuel cell in any one of Claim 1 to 3.

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