JP2009187847A - Manufacturing method for support of fuel cell and manufacturing method for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a fuel cell and a manufacturing method for a support of a fuel cell capable of restraining oxygen shortage in an electrolyte while restraining oxidation of a metal support. <P>SOLUTION: The manufacturing method for a fuel cell 100 comprises a first arrangement process of arranging a protection layer 20 made of formation metal of an oxide electrode or formation metal of an oxide electrolyte on a metal support 10 having gas permeability, a second arrangement process of arranging an oxide electrolyte 30 on the protection layer 20, and a calcining process of calcining the oxide electrolyte and the protection layer under an oxidizing atmosphere. Oxidation of the metal support can be restrained on this manufacturing method for a fuel cell since the calcining process is carried out after the protection layer is arranged. Further, oxygen shortage in the oxide electrolyte can be restrained since the oxidizing atmosphere can be used in the calcining process. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a fuel cell support and a method for manufacturing a fuel cell.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. Since this fuel cell is excellent in terms of the environment and can realize high energy efficiency, it has been widely developed as a future energy supply system.

  Examples of the fuel cell using a solid electrolyte include a solid polymer fuel cell and a solid oxide fuel cell. In a solid oxide fuel cell, a porous support for supporting an electrolyte may be used.

  Patent Document 1 discloses a solid oxide fuel cell using a porous ceramic substrate made of a ceramic material such as alumina or zirconia and having a large number of through-holes communicating with both front and back surfaces.

JP 2005-166455 A

  By the way, a porous metal support may be used as the porous support. If the electrolyte is baked on the metal support, the metal support may be oxidized. In this case, the electrical resistance may increase. Therefore, when the electrolyte is baked in a hydrogen atmosphere, oxygen in the electrolyte may be insufficient. As a result, there is a possibility that sufficient conductivity cannot be obtained for the electrolyte.

  An object of this invention is to provide the manufacturing method of the fuel cell which can suppress the oxygen shortage in electrolyte, and the manufacturing method of the support body for fuel cells, suppressing the oxidation of a metal support body.

  The fuel cell manufacturing method according to the present invention includes a first disposing step of disposing a protective layer made of a constituent metal of an oxide electrode or a constituent metal of an oxide electrolyte on a gas-permeable metal support, A second disposing step of disposing the oxide electrolyte, and a firing step of firing the oxide electrolyte and the protective layer in an oxidizing atmosphere. According to the method for manufacturing a fuel cell according to the present invention, since the firing step is performed after the protective layer is disposed, the oxidation of the metal support is suppressed. Thereby, an increase in electric resistance of the fuel cell can be suppressed. In addition, since an oxidizing atmosphere can be used in the firing step, oxygen deficiency in the oxide electrolyte can be suppressed. As a result, high ionic conductivity is obtained in the oxide electrolyte.

  The manufacturing method may further include a forming process step of performing an electrode forming process on the lower surface of the metal support, and the protective layer may be a constituent metal of the oxide electrolyte. According to this manufacturing method, when the protective layer is a constituent metal of an oxide electrolyte, an electrode can be formed on the lower surface of the metal support.

  The manufacturing method may further include a removal step of removing the oxide film on the lower surface of the metal support after the firing step. According to this manufacturing method, an increase in electric resistance of the fuel cell due to the oxide film can be suppressed. The above manufacturing method may further include a step of forming an electrode on the oxide electrolyte.

  In the above manufacturing method, the metal support may be made of ferritic stainless steel. According to this manufacturing method, the fuel cell can be manufactured at a low cost, and separation of the metal support and the oxide electrolyte in the manufactured fuel cell can be suppressed.

  The fuel cell support manufacturing method according to the present invention includes a disposing step of disposing a protective layer made of a constituent metal of an oxide electrode or a constituent metal of an oxide electrolyte on a metal support having gas permeability, and an oxidizing atmosphere. And a firing step of firing the protective layer. According to the method for manufacturing a fuel cell support according to the present invention, since the firing step is performed after the protective layer is disposed, the oxidation of the metal support is suppressed. Thereby, when the support body for fuel cells is used for a fuel cell, the increase in the electrical resistance of a fuel cell can be suppressed. In addition, since the protective layer is disposed, oxygen deficiency in the oxide electrolyte can be suppressed when the oxide electrolyte is baked on the fuel cell support. As a result, high ionic conductivity is obtained in the oxide electrolyte.

  In the above manufacturing method, the metal support may be made of ferritic stainless steel. According to this manufacturing method, the fuel cell support can be manufactured at a low cost, and the separation of the metal support and the oxide electrolyte when the oxide electrolyte is formed on the manufactured fuel cell support is suppressed. be able to.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the fuel cell which can suppress the oxygen deficiency in electrolyte while suppressing the oxidation of a metal support body, and the manufacturing method of the support body for fuel cells can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described.

  A method for manufacturing the fuel cell 100 according to Embodiment 1 of the present invention will be described. FIG. 1A to FIG. 1E are manufacturing process diagrams illustrating a method for manufacturing the fuel cell 100 according to the first embodiment. 1A to 1E are cross-sectional views.

  First, as shown in FIG. 1A, a metal support 10 having gas permeability is prepared. The metal support 10 functions as a support substrate for the fuel cell 100. The metal support 10 is made of a porous metal having a plurality of holes 12 formed therein. In the present embodiment, the hole 12 is a through-hole penetrating from the lower surface side to the upper surface side of the metal support 10. The gas supplied to the metal support 10 passes through the hole 12 and passes through the metal support 10 from the lower surface side to the upper surface side. Although the thickness of the metal support body 10 is not specifically limited, For example, they are 10 micrometers-several hundred micrometers. The diameter of the hole 12 is not particularly limited, but is about 20 μm, for example. The metal which comprises the metal support body 10 is not specifically limited.

Next, the protective layer arranging step shown in FIG. The protective layer arranging step is a step of arranging the protective layer 20 on the metal support 10. The protective layer 20 is made of a constituent metal of the oxide electrode. In the present embodiment, the protective layer 20 is made of a constituent metal of the cathode electrode 50 described later. Examples of the cathode electrode 50 include LaSrCoO ₃ , La _0.8 Sr _0.2 MnO ₃ , Pr _0.8 Sr _0.2 CoO ₃ , La _0.8 Sr _0.2 CoO ₃ , and Pr _0.5 Sr _{0. .5} CoO ₃ , La _0.8 Sr _0.2 FeO ₃ , Pr _0.8 Sr _0.2 FeO ₃ , La _0.7 Sr _0.25 FeO ₃ , Ba _0.5 Sr _0.5 Co _0.8 Ceramics such as Fe _0.2 O ₃ , La _0.8 Sr _0.2 Co _0.8 Fe _0.2 O ₃ , La _0.6 Sr _0.4 Co _0.8 Fe _0.2 O ₃ are used. . In this embodiment, as an example, LaSrCoO ₃ is used for the cathode electrode 50. Therefore, in this embodiment, a LaSrCo alloy is used as the protective layer 20.

  Examples of the method for arranging the protective layer 20 include screen printing, spraying with colloid spray, sputtering, ion plating, thermal spraying, EB deposition, sol-gel method, plating, and the like.

Next, the electrolyte placement step shown in FIG. The electrolyte disposing step is a step of disposing the oxide electrolyte 30 on the protective layer 20. As the oxide electrolyte 30, an oxygen ion conductive electrolyte or a proton conductive electrolyte is used. As the oxygen ion conductive electrolyte, for example, ceramics such as GdCeO ₂ , SmCeO ₂ , YSZ (ZrYO ₂ ), (La, Sr) (Ga, Mg) O ₃ are used. As the proton conductive electrolyte, for example, ceramics such as BaCeO ₃ , BaZrO ₃ , SrZrO ₃ , SrCeO ₃ are used. In this embodiment, GdCeO ₂ having oxygen ion conductivity is used as the oxide electrolyte 30.

  The arrangement method of the oxide electrolyte 30 is not particularly limited as long as the ceramic electrolyte can be arranged. As a method for arranging the oxide electrolyte 30, for example, methods such as screen printing, spraying with a colloid spray, sputtering, ion plating, thermal spraying, EB deposition, sol-gel method, plating, and the like are used.

Subsequently, the baking process shown in FIG.1 (d) is performed. The firing step is a step of firing the protective layer 20 and the oxide electrolyte 30 in an oxidizing atmosphere containing oxygen. By the firing step, the oxide electrolyte 30 becomes dense and the LaSrCo alloy constituting the protective layer 20 is oxidized to LaSrCoO ₃ . The firing conditions are not particularly limited as long as the oxide electrolyte 30 can be densified and the protective layer 20 can be oxidized. In this embodiment, the atmosphere is an air atmosphere, the temperature is about 1200 ° C. to 1400 ° C., and the time is about 3 hours. Through the process of FIG. 1D, the protective layer 20 is oxidized to have electrode activity. That is, the protective layer 20 can exhibit the function as the cathode electrode 50 by the process of FIG.

Next, the anode electrode film forming step shown in FIG. The anode electrode film forming step is a step of forming the anode electrode 40 on the oxide electrolyte 30. As the anode electrode 40, for example, ceramics such as (GdCeO ₂ + NiO), (SmCeO ₂ + NiO), (YSZ (ZrYO ₂ ) + NiO), ((La, Sr) (Ga, Mg) O ₃ + NiO) are used. . In this embodiment, (GdCeO ₂ + NiO) is used as the anode electrode 40.

  The method for forming the anode electrode 40 is not particularly limited as long as it is a method capable of forming a ceramic film. As a method for forming the anode electrode 40, for example, methods such as screen printing, spraying with colloid spray, sputtering, ion plating, thermal spraying, EB deposition, sol-gel method, plating, etc. are used. The fuel cell 100 is manufactured by the above manufacturing method.

The fuel cell 100 generates power by the following action. First, hydrogen (H ₂ ) is supplied to the anode electrode 40. Oxygen (O ₂ ) is supplied to the metal support 10. Oxygen supplied to the metal support 10 reaches the cathode electrode 50 through the hole 12.

  In the cathode electrode 50, oxygen that has passed through the metal support 10 and reached the cathode electrode 50 reacts with electrons that have reached the cathode electrode 50 through an external electric circuit to become oxygen ions. The oxygen ions are transferred to the anode electrode 40 side through the oxide electrolyte 30.

The hydrogen supplied to the anode electrode 40 emits electrons at the anode electrode 40 and reacts with oxygen ions moving through the oxide electrolyte 30 from the cathode electrode 50 side to become water (H ₂ O). The emitted electrons are taken out by an external electric circuit that electrically connects the anode electrode 40 and the cathode electrode 50. The electrons taken out to the outside reach the cathode electrode 50 after performing electrical work. Power generation is performed by the above operation.

  According to the method for manufacturing the fuel cell 100 according to the present embodiment, since the firing step is performed after the protective layer 20 is disposed, the oxidation of the metal support 10 is suppressed. Thereby, an increase in electric resistance of the fuel cell 100 can be suppressed. In addition, since an oxidizing atmosphere can be used in the firing step, oxygen deficiency in the oxide electrolyte 30 can be suppressed. As a result, high ionic conductivity is obtained in the oxide electrolyte 30.

In the present embodiment, the protective layer 20 is made of a constituent metal of the cathode electrode 50, but is not limited thereto. For example, the protective layer 20 may be made of a constituent metal of the anode electrode 40. In this case, for example, when the anode electrode 40 is (GdCeO ₂ + NiO), the protective layer 20 is a GdCeNi alloy. In this case, the anode electrode 40 is disposed instead of the cathode electrode 50 in the step of FIG.

  Moreover, it is preferable to use ferritic stainless steel as the metal support 10. This is because ferritic stainless steel is available at low cost and has a thermal expansion coefficient close to that of the oxide electrolyte 30. Note that when the coefficient of thermal expansion of the metal support 10 and the coefficient of thermal expansion of the oxide electrolyte 30 are close, peeling between the metal support 10 and the oxide electrolyte 30 is suppressed.

Moreover, it is preferable that the oxide electrolyte 30 and the anode electrode 40 contain the same ceramics. In this case, since the crystal structure of the oxide electrolyte 30 and the crystal structure of the anode electrode 40 are close to each other, the bond between the oxide electrolyte 30 and the anode electrode 40 is strengthened. For example, when the oxide electrolyte 30 is GdCeO ₂ , the anode electrode 40 is (GdCeO ₂ + NiO), and when the oxide electrolyte 30 is YSZ (ZrYO ₂ ), the anode electrode 40 is (YSZ (ZrYO ₂ ) + NiO). Preferably there is.

  In this embodiment, the protective layer arranging step of FIG. 1B corresponds to the first arranging step according to claim 1, and the electrolyte arranging step of FIG. 1C corresponds to the second arranging step of claim 1. The firing step in FIG. 1D corresponds to the firing step described in claim 1.

  In this embodiment, when manufacturing a fuel cell support, the process of FIG. 1 (d) may be performed after the processes of FIG. 1 (a) and FIG. 1 (b) are performed. In this case, the protective layer arranging step of FIG. 1B corresponds to the arranging step described in claim 6, and the baking step of FIG. 1D corresponds to the baking step of claim 6.

  Then, the manufacturing method of the fuel cell 100a which concerns on Example 2 of this invention is demonstrated. FIG. 2A to FIG. 2F are manufacturing process diagrams illustrating a method of manufacturing the fuel cell 100a according to the second embodiment. 2A to 2F, cross-sectional views are shown. First, as shown in FIG. 2A, a metal support 10 is prepared. The process of FIG. 2A is the same as the process of FIG.

  Next, the protective layer arranging step shown in FIG. The protective layer arranging step is a step of arranging the protective layer 20 a on the metal support 10. The protective layer 20a is different from the protective layer 20 of FIG. 1B in that it is made of a constituent metal of the oxide electrolyte 30. Other configurations are the same as those of the protective layer 20 in FIG.

For example, when the oxide electrolyte 30 is GdCeO ₂ , the constituent metals of the oxide electrolyte 30 are Gd and Ce. That is, in this case, the protective layer 20a is made of a GdCe alloy.

  As a method for arranging the protective layer 20a, for example, methods such as screen printing, spraying with a colloid spray, sputtering, ion plating, thermal spraying, EB deposition, sol-gel method, plating, and the like are used.

  Next, the electrolyte placement step shown in FIG. The electrolyte disposing step is a step of disposing the oxide electrolyte 30 on the protective layer 20a. The electrolyte arrangement process in FIG. 2C is the same as the electrolyte arrangement process in FIG.

Next, the cathode electrode forming process shown in FIG. The cathode electrode forming process is a process for forming the cathode electrode 50 on the lower surface of the metal support 10. In the present embodiment, for example, LaSrCoO ₃ is formed as the cathode electrode 50. Examples of the method for forming the cathode electrode 50 include screen printing, spraying with colloid spray, sputtering, ion plating, thermal spraying, EB deposition, sol-gel method, plating, and the like. In the present embodiment, the cathode electrode 50 is formed in the hole 12 of the metal support 10 by the process of FIG.

Next, the firing step shown in FIG. The firing step is a step of firing the protective layer 20a and the oxide electrolyte 30 in an oxidizing atmosphere. By the firing step, the GdCe alloy constituting the protective layer 20a is oxidized to GdCeO ₂ and the oxide electrolyte 30 and GdCeO ₂ constituting the protective layer 20a are densified. In this embodiment, the atmosphere is an air atmosphere, the temperature is about 1200 ° C. to 1400 ° C., and the time is about 3 hours.

  2E, the protective layer 20a is oxidized to exhibit ionic conductivity. That is, the protective layer 20a can exhibit a function as an oxide electrolyte by the process of FIG. The protective layer 20a after the step of FIG. 2 (e) is referred to as an oxide electrolyte 30a. In this case, the oxide electrolyte 30a and the oxide electrolyte 30 are integrated to function as the electrolyte of the fuel cell 100a.

  Next, the anode electrode film forming step shown in FIG. The anode electrode film forming step is a step of disposing the anode electrode 40 on the oxide electrolyte 30 disposed in the electrolyte disposing step of FIG. The second electrode placement step in FIG. 2F is the same as the anode electrode film formation step in FIG. The fuel cell 100a is manufactured by the above manufacturing method.

  According to the manufacturing method of the fuel cell 100a according to the present embodiment, since the firing step is performed after the protective layer 20a is disposed, the oxidation of the metal support 10 is suppressed. Thereby, an increase in electric resistance of the fuel cell 100a can be suppressed. In addition, since an oxidizing atmosphere can be used in the firing step, oxygen deficiency in the oxide electrolytes 30 and 30a can be suppressed. As a result, high ionic conductivity is obtained in the oxide electrolytes 30 and 30a.

  In the step of FIG. 2D, the cathode electrode 50 is formed, but the present invention is not limited to this. For example, the anode electrode 40 may be formed in the process of FIG. In this case, in the step of FIG. 2 (f), the cathode electrode 50 is formed instead of the anode electrode 40.

  Moreover, although the cathode electrode formation process of FIG.2 (d) is performed before the baking process of FIG.2 (e), it is not restricted to this. The execution time of the cathode electrode forming process is not particularly limited.

  In this embodiment, the protective layer arranging step in FIG. 2B corresponds to the first arranging step according to claim 1, and the electrolyte arranging step in FIG. 2C corresponds to the second arranging step according to claim 1. 2 (d) corresponds to the forming process described in claim 2, and the baking process in FIG. 2 (e) corresponds to the baking process described in claim 1.

  Further, in the present embodiment, when the fuel cell support is manufactured, the step of FIG. 2 (e) may be executed after the steps of FIG. 2 (a) and FIG. 2 (b) are executed. In this case, the protective layer arranging step in FIG. 2B corresponds to the arranging step described in claim 6, and the baking step in FIG. 2E corresponds to the baking step described in claim 6.

  Then, the manufacturing method of the fuel cell stack 200 which concerns on Example 3 of this invention is demonstrated. FIG. 3A to FIG. 3C are manufacturing process diagrams illustrating a method for manufacturing the fuel cell stack 200 according to the third embodiment. 3A to 3C are cross-sectional views. First, as shown in FIG. 3A, a fuel cell 100b is prepared. As the fuel cell 100b, either the fuel cell 100 manufactured by the manufacturing method according to the first embodiment or the fuel cell 100a manufactured by the manufacturing method according to the second embodiment can be used. In the present embodiment, the fuel cell 100 according to the first embodiment is used as the fuel cell 100b.

  Next, the oxide film removal step shown in FIG. In the case where the metal support 10 is made of metal, an oxide film is formed on the surface of the metal support 10 of the fuel cell 100b opposite to the cathode electrode 50 by the firing process of FIG. Therefore, in the oxide film removal step, the oxide film formed on the surface opposite to the cathode electrode 50 of the metal support 10 of the fuel cell 100b is removed. As the oxide film removal method, an oxide film removal method such as mechanical polishing or chemical etching can be used.

  Next, as shown in FIG. 3C, a plurality of fuel cells 100 b are stacked via the separator 60. The fuel cell stack 200 is manufactured by the above manufacturing method. According to the manufacturing method of the fuel cell stack 200 according to the present embodiment, an increase in electric resistance due to the oxide film can be suppressed.

FIG. 1A to FIG. 1E are manufacturing process diagrams illustrating a method of manufacturing a fuel cell according to the first embodiment. FIG. 2A to FIG. 2F are manufacturing process diagrams illustrating a method of manufacturing a fuel cell according to the second embodiment. FIG. 3A to FIG. 3C are manufacturing process diagrams illustrating a method for manufacturing a fuel cell stack according to the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Metal support body 12 Hole part 20 Protective layer 30 Oxide electrolyte 40 Anode electrode 50 Cathode electrode 60 Separator 100 Fuel cell 200 Fuel cell stack

Claims (7)

A first disposing step of disposing a protective layer made of a constituent metal of an oxide electrode or a constituent metal of an oxide electrolyte on a metal support having gas permeability;
A second disposing step of disposing an oxide electrolyte on the protective layer;
And a firing step of firing the oxide electrolyte and the protective layer in an oxidizing atmosphere. Further comprising a forming process step of performing an electrode forming process on the lower surface of the metal support,
The method for manufacturing a fuel cell according to claim 1, wherein the protective layer is a constituent metal of the oxide electrolyte.   3. The method of manufacturing a fuel cell according to claim 1, further comprising a removing step of removing an oxide film on a lower surface of the metal support after the firing step. 4.   The method for producing a fuel cell according to claim 1, further comprising a step of forming an electrode on the oxide electrolyte.   The method of manufacturing a fuel cell according to claim 1, wherein the metal support is made of ferritic stainless steel. A disposing step of disposing a protective layer made of a constituent metal of an oxide electrode or a constituent metal of an oxide electrolyte on a metal support having gas permeability;
And a firing step of firing the protective layer in an oxidizing atmosphere.   The method of manufacturing a fuel cell support according to claim 6, wherein the metal support is made of ferritic stainless steel.

Images