JP2012089443A - Manufacturing method of fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a fuel cell capable of suppressing delamination of a second member from a first member.SOLUTION: The manufacturing method of a fuel cell including a first member 10 and a second member 20 includes a sintering step for sintering the second member 20 on the first member 10. The sintering step includes a sintering sub-step in which the start of sintering of the bottom surface of the second member 20 is intended to take place prior to the start of sintering of the upper surface of the second member 20. According to the manufacturing method, delamination of the second member 20 from the first member 10 can be suppressed.

Description

  The present invention relates to 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.

  The fuel cell has a structure in which a porous substrate, one electrode, an electrolyte layer, and the other electrode are laminated in this order (see, for example, Patent Document 1). In this fuel cell, for example, on the first member (porous substrate, one electrode, electrolyte layer), the second member (one electrode and one member when the first member is a porous substrate) In the case of an electrode, it is manufactured including a firing step of sintering an electrolyte layer, and in the case where the first member is an electrolyte layer, the other electrode).

JP 2009-59697 A

  However, in the above manufacturing method, the degree of adhesion between the second member and the first member at the time of sintering is insufficient, and the second member may be peeled off from the first member.

  An object of this invention is to provide the manufacturing method of the fuel cell which can suppress peeling from the 1st member of a 2nd member.

  A method of manufacturing a fuel cell according to the present invention is a method of manufacturing a fuel cell including a first member and a second member, and includes a firing step of sintering the second member on the first member, It includes a firing step of firing so that the start of sintering of the lower surface of the second member precedes the start of sintering of the upper surface of the second member.

  According to the method for manufacturing a fuel cell according to the present invention, after the lower surface of the second member starts sintering and comes into close contact with the first member, the upper surface of the second member starts to be sintered. Thereby, peeling of the second member from the first member can be suppressed.

  In the above method, the firing step may include a step of applying and sintering a second member constituting material constituting the second member on the first member a plurality of times. In the above method, the firing step further includes a provisional firing step of pre-sintering the second member constituent material under conditions where sintering is not completed, and a second member constituent material is further disposed on the pre-sintered second member constituent material. And a main firing step of sintering the preliminarily sintered second member constituent material and further arranged second member constituent material. In the above method, the firing temperature in the preliminary firing step may be lower than the firing temperature in the main firing step.

  In the firing step, the temperature of the second member may be lowered sequentially from the lower surface to the upper surface. According to this method, the sintering start of the lower surface of the second member can be preceded by the sintering start of the upper surface of the second member. Thereby, peeling of the second member from the first member can be suppressed. In the firing step, a heat source may be disposed on the opposite side of the first member from the second member.

  In the above method, the first member may be an electrode, and the second member may be a solid oxide electrolyte. In the above method, the first member may be a porous substrate, and the second member may be an electrode containing a solid oxide. In the above method, the first member may be a solid oxide electrolyte, and the second member may be an electrode containing a solid oxide.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the fuel cell which can suppress peeling from the 1st member of a 2nd member can be provided.

It is typical sectional drawing of a fuel cell. 6 is a schematic cross-sectional view showing an anode forming step according to Example 1. FIG. 3 is a schematic cross-sectional view showing an electrolyte layer forming step according to Example 1. FIG. 3 is a schematic cross-sectional view showing an electrolyte layer forming step according to Example 1. FIG. FIG. 3 is a schematic cross-sectional view showing a cathode forming step according to Example 1. 6 is a schematic cross-sectional view showing an example of an electrolyte layer forming step according to Example 2. FIG. 6 is a schematic cross-sectional view showing another example of the electrolyte layer forming step according to Example 2. FIG.

  Hereinafter, modes 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. First, the configuration of the fuel cell 100 will be described, and then the manufacturing method according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional view of the fuel cell 100. The fuel cell 100 has a structure in which the support 10, one electrode, the electrolyte layer 30, and the other electrode are stacked in this order. In this embodiment, the fuel cell 100 has a structure in which the support 10, the anode 20, the electrolyte layer 30, and the cathode 40 are laminated in this order as an example.

  As the support 10, a member having gas permeability and capable of supporting the electrolyte layer 30 can be used. In this embodiment, a porous substrate is used as an example of the support 10. As an example of the porous substrate, a porous metal plate having a plurality of holes 11 communicating with the upper surface and the lower surface is used. The material of the porous metal plate is not particularly limited. For example, a material (such as stainless steel) containing a component that forms an insulating oxide film on the surface by oxidation is used.

The material of the anode 20 is not particularly limited as long as it has electrode activity as an anode. For example, an electrode material containing a solid oxide such as NiO / ZrO ₂ , NiO / CeO ₂ , NiO / BaZrO _3, or the like is used. Can be used.

The material of the electrolyte layer 30 is not particularly limited. For example, a solid oxide electrolyte such as ZrO ₂ , CeO ₂ , LaGaO ₃ , or BaZrO ₃ can be used.

The material of the cathode 40 is not particularly limited as long as it has electrode activity as a cathode. For example, an electrode material containing a solid oxide such as LaMnO ₃ , LaCoO ₃ , La ₂ NiO ₄ , or SmCoO _{3 is} used. Can be used.

The fuel cell 100 generates power by the following action. First, hydrogen (H ₂ ) is supplied to the support 10, and oxygen (O ₂ ) is supplied to the cathode 40. In the cathode 40, oxygen supplied to the cathode 40 and electrons supplied from the external electric circuit react to form oxygen ions. In the case of an oxygen ion conductive electrolyte, oxygen ions are transferred to the anode 20 side through the electrolyte layer 30.

On the other hand, the hydrogen supplied to the support 10 passes through the holes 11 of the support 10 and reaches the anode 20. The hydrogen that has reached the anode 20 emits electrons at the anode 20 and reacts with oxygen ions conducted through the electrolyte layer 30 from the cathode 40 side to become water (H ₂ O). The emitted electrons are taken out by an external electric circuit. The electrons extracted outside are supplied to the cathode 40 after performing electrical work. Power generation is performed by the above operation.

  Then, the manufacturing method of the fuel cell 100 is demonstrated. The manufacturing process of the fuel cell 100 according to the present embodiment includes a process of forming the anode 20 (hereinafter referred to as an anode forming process), a process of forming the electrolyte layer 30 (hereinafter referred to as an electrolyte layer forming process), a cathode 40 (hereinafter referred to as a cathode formation step). 2 is a schematic cross-sectional view showing the anode forming step, FIGS. 3 and 4 are schematic cross-sectional views showing the electrolyte layer forming step, and FIG. 5 is a schematic cross-sectional view showing the cathode forming step.

  First, the anode forming process will be described. As shown in FIG. 2A, a constituent material of the anode 20 (hereinafter referred to as an anode constituent material 21) is applied on the support 10.

  Next, as shown in FIG. 2B, a temporary firing step is performed in which the anode constituent material 21 is presintered under the condition that the sintering is not completed. As an example of conditions under which sintering is not completed, in this embodiment, firing at a temperature lower than the firing temperature in the main firing step is used. That is, in the anode forming step of this example, the firing temperature in the temporary firing step is lower than the firing temperature in the main firing step. The anode constituent material after the preliminary firing step is referred to as an anode temporary sintered body 22. In the present embodiment, the firing temperature refers to the temperature of the member to be sintered as an example. For example, in FIG. 2B, the firing temperature is the temperature of the anode constituent material 21.

  Next, as shown in FIG. 2C, an anode constituent material 21 is further applied onto the anode preliminary sintered body 22. Next, as shown in FIG. 2 (d), a main firing step is performed in which the anode preliminary sintered body 22 and the anode constituent material 21 are sintered under conditions for completing the sintering. As a result, the anode pre-sintered body 22 and the anode constituent material 21 become porous and integrated into the anode 20 as shown in FIG. The anode forming step is performed through the above steps.

  The effects of the anode forming process will be described in comparison with the anode forming process according to the comparative example. In the anode forming process according to the comparative example, the anode 20 is formed without performing the preliminary sintering process. Specifically, in the anode forming step according to the comparative example, after the anode constituent material 21 having the same thickness as the completed anode 20 is applied on the support 10, the anode constituent material 21 is completely sintered. It is enforced by performing a main firing step of sintering under conditions.

  In the case of the anode forming step according to the comparative example, the anode constituent material 21 may be sintered while being peeled from the support 10 during firing. In this case, the anode 20 may be cracked. As a cause of this peeling, it is considered that the degree of adhesion between the support 10 and the anode constituent material 21 is not sufficient when the sintering of the anode constituent material 21 is started and volume shrinkage is started.

  More specifically, when the anode constituent material 21 is sintered in the anode forming step according to the comparative example, the upper surface of the anode constituent material 21 is exposed to the outside as compared with the lower surface. However, the upper surface tends to be hot. Therefore, the upper surface starts sintering earlier than the lower surface of the anode constituent material 21. As a result, the upper surface of the anode constituent material 21 starts to contract before the lower surface in a state where the adhesion between the lower surface of the anode constituent material 21 and the support 10 is insufficient. As a result, it is considered that the lower surface of the anode constituent material 21 is peeled off from the support 10.

  On the other hand, according to the anode forming step according to the present embodiment, when the upper surface of the anode constituent material 21 disposed on the anode preliminary sintered body 22 starts sintering in the main firing step, the anode temporary The lower surface of the sintered body 22 is in a state where sintering is started. That is, the anode forming step according to the present example is fired so that the sintering start of the lower surface of the anode constituent material 21 disposed on the support 10 precedes the sintering start of the upper surface of the anode constituent material 21. It is a process including a baking process.

  In this case, in the main firing step, the upper surface of the anode constituent material 21 on the anode temporary sintered body 22 starts sintering while the support 10 and the anode temporary sintered body 22 are in close contact with each other. Further, peeling between the anode pre-sintered body 22 and the anode constituent material 21 is suppressed because both are the same material. Therefore, peeling of the anode 20 from the support 10 is suppressed. As a result, cracks in the anode 20 are suppressed.

  Subsequently, an electrolyte layer forming step according to the present embodiment will be described. First, as shown in FIG. 3A, a constituent material of the electrolyte layer 30 (hereinafter referred to as an electrolyte layer constituent material 31) is applied on the anode 20 manufactured in the anode forming step.

  Next, as shown in FIG. 3B, a temporary firing step is performed in which the electrolyte layer constituent material 31 is presintered under the condition that the sintering is not completed. As an example of conditions under which the sintering is not completed, in this embodiment, firing at a temperature lower than the firing temperature in the main firing step described later is used. That is, in the electrolyte layer forming step of this example, the firing temperature in the temporary firing step is lower than the firing temperature in the main firing step. The electrolyte layer constituent material after the preliminary firing step is referred to as an electrolyte layer temporary sintered body 32. The thickness of the electrolyte layer pre-sintered body 32 is not particularly limited, but is about several μm, for example.

  Next, as shown in FIG. 3C, an electrolyte layer constituting material 31 is further applied on the electrolyte layer temporary sintered body 32. The thickness of the electrolyte layer constituting material 31 is not particularly limited, but is, for example, about several tens of μm. Next, as shown in FIG. 4A, a main firing step is performed in which the electrolyte layer temporary sintered body 32 and the electrolyte layer constituent material 31 are sintered at a temperature at which the sintering is completed. Thereby, the electrolyte layer pre-sintered body 32 and the electrolyte layer constituent material 31 become dense and are integrated into an electrolyte layer 30 as shown in FIG. The electrolyte formation step is performed by the above steps.

  According to the electrolyte layer forming step according to the present embodiment, when the upper surface of the electrolyte layer constituent material 31 disposed on the electrolyte layer temporary sintered body 32 starts sintering, the electrolyte layer temporary sintered body 32 has already been sintered. The lower surface starts sintering and is in close contact with the anode 20. Thereby, peeling of the electrolyte layer 30 from the anode 20 is suppressed. As a result, cracks in the electrolyte layer 30 are suppressed.

  Next, the cathode forming process according to this example will be described. First, as shown in FIG. 5A, a material of the cathode 40 (hereinafter referred to as a cathode constituent material 41) is applied on the electrolyte layer 30 manufactured in the electrolyte layer forming step.

  Next, as shown in FIG. 5B, a temporary firing step is performed in which the cathode constituent material 41 is pre-sintered under the condition that the sintering is not completed. As an example of conditions under which the sintering is not completed, in this embodiment, firing at a temperature lower than the firing temperature in the main firing step described later is used. That is, in the cathode formation step of this example, the firing temperature in the temporary firing step is lower than the firing temperature in the main firing step. The cathode constituent material after the preliminary firing step is referred to as a cathode preliminary sintered body 42.

  Next, as shown in FIG. 5C, a cathode constituent material 41 is further applied on the cathode preliminary sintered body 42. Next, as shown in FIG. 5A, a main firing step is performed in which the cathode preliminary sintered body 42 and the cathode constituent material 41 are sintered at a temperature at which the sintering is completed. Thereby, the cathode pre-sintered body 42 and the cathode constituent material 41 become porous and are integrated into a cathode 40 as shown in FIG. The electrolyte formation step is performed by the above steps. Further, the fuel cell 100 is manufactured through the above steps.

  According to the cathode forming step according to the present embodiment, when the upper surface of the cathode constituent material 41 arranged on the cathode preliminary sintered body 42 starts sintering, the lower surface of the cathode preliminary sintered body 42 has already been sintered. Is in close contact with the electrolyte layer 30. Thereby, peeling of the cathode 40 from the electrolyte layer 30 is suppressed. As a result, cracks in the cathode 40 are suppressed.

  In addition, the heating method at the time of the temporary baking process and the main baking process in the anode forming process, the electrolyte layer forming process, and the cathode forming process of the present embodiment is not particularly limited. For example, a heat source such as an infrared lamp or a heating element (heated SiC or the like) may be disposed in a desired place to perform the temporary firing step and the main firing step.

  Further, at least one of the anode forming step, the electrolyte layer forming step, and the cathode forming step may include a firing step having a temporary firing step. In addition, it is preferable that at least the electrolyte layer forming step includes a firing step having a temporary firing step. This is because the anode 20 and the cathode 40 are porous and the electrolyte layer 30 is dense, so that the performance degradation of the fuel cell 100 when cracks occur is larger in the electrolyte layer 30 than in the anode 20 and cathode 40.

  In this embodiment, the anode forming step, the electrolyte layer forming step, and the cathode forming step include a temporary baking step and a baking step, and include a step of applying and sintering the constituent material twice. However, the number of times of applying and sintering the constituent material is not limited and may be performed three or more times. In this embodiment, the firing temperature in the preliminary firing step is set lower than the firing temperature in the main firing step, but the present invention is not limited to this as long as the sintering of the constituent materials is not completed.

  Then, the manufacturing method of the fuel cell 100 which concerns on Example 2 of this invention is demonstrated. First, the electrolyte layer forming process according to the present embodiment will be described. The electrolyte layer forming step according to the present example is different from the electrolyte layer forming step according to Example 1 in that peeling of the electrolyte layer 30 is suppressed without performing a temporary firing step. FIG. 6A and FIG. 6B are schematic cross-sectional views showing an example of the electrolyte layer forming step according to the present example. First, as shown in FIG. 6A, an electrolyte layer constituting material 31 is applied on the anode 20. The thickness of the electrolyte layer constituting material 31 at this time is adjusted so that the completed electrolyte layer 30 has a desired thickness.

  Next, as shown in FIG. 6B, a main firing step is performed in which the electrolyte layer constituting material 31 is sintered under the conditions for completing the sintering. The main firing step according to the present example is performed in a state where the electrolyte layer constituent material 31 is heated by a heat source so that the temperature of the electrolyte layer constituent material 31 decreases in order from the lower surface to the upper surface.

  As an example of heating by this heat source, in the main baking step in the present embodiment, the heat source 200 is disposed on the side opposite to the electrolyte layer constituting material 31 of the support 10, and the heat source 200 is provided on the electrolyte layer constituting material 31 side of the support 10. Done without placing. In this case, the temperature increases in the order of the support 10, the anode 20, and the electrolyte layer constituent material 31. As a result, the temperature of the electrolyte layer constituent material 31 decreases in order from the lower surface to the upper surface. The type of the heat source 200 is not particularly limited, but an infrared lamp is used as an example in this embodiment. Through the above steps, the electrolyte layer forming step according to this example is performed.

  According to the electrolyte layer forming step according to the present example, the temperature of the electrolyte layer constituent material 31 decreases in order from the lower surface to the upper surface, and thus the electrolyte layer constituent material 31 starts sintering in order from the lower surface to the upper surface. . As a result, the electrolyte layer constituent material 31 is sintered from the lower surface in close contact with the anode 20 to the upper surface. As a result, peeling of the electrolyte layer 30 from the anode 20 is suppressed, and the occurrence of cracks in the electrolyte layer 30 is suppressed.

  In addition, the main baking process of the electrolyte layer formation process which concerns on a present Example is not restricted to the method of FIG.6 (b). FIG. 7 is a schematic cross-sectional view illustrating another example of the electrolyte layer forming step according to the second embodiment. In FIG. 7, the number of the heat sources 200 arranged on the side opposite to the electrolyte layer constituting material 31 of the support 10 is larger than the number of the heat sources 200 arranged on the electrolyte layer constituting material 31 side of the support 10. Even in this case, the temperature of the electrolyte layer constituting material 31 decreases in order from the lower surface to the upper surface. Thereby, peeling of the electrolyte layer 30 from the anode 20 is suppressed, and the generation of cracks in the electrolyte layer 30 is suppressed.

  The anode forming step according to the present example is also performed by the same method as the electrolyte layer forming step. Specifically, in the anode forming step, after the anode constituent material is applied on the support 10, the main firing step is performed without performing the temporary firing step. The main firing step is performed in a state where the anode constituent material is heated by the heat source 200 so that the temperature of the anode constituent material decreases in order from the lower surface to the upper surface. In this case, the anode constituent material starts sintering sequentially from the lower surface to the upper surface. As a result, peeling of the anode is suppressed, and generation of cracks is suppressed.

  Further, the cathode forming step according to the present embodiment is also performed by the same method as the electrolyte layer forming step. Specifically, in the cathode forming step, after the cathode constituent material is applied on the electrolyte layer 30, the main firing step is performed without performing the temporary firing step. The main firing step is performed in a state where the cathode constituent material is heated by the heat source 200 so that the temperature of the cathode constituent material decreases in order from the lower surface to the upper surface. In this case, the cathode constituent material starts sintering sequentially from the lower surface to the upper surface. As a result, the peeling of the cathode is suppressed and the generation of cracks is suppressed.

  In this embodiment, at least one of the anode forming step, the electrolyte layer forming step, and the cathode forming step is a firing step according to this embodiment, that is, the temperature of the component to be fired is from the lower surface to the upper surface. What is necessary is just to include the baking process which becomes low in order. Further, in the anode forming step, the electrolyte layer forming step, and the cathode forming step according to Example 1, the heat source 200 may be arranged as shown in FIG. 6B or FIG.

  The manufacturing method according to the first and second embodiments may be applied when manufacturing a fuel cell having a structure in which the support 10, the cathode 40, the electrolyte layer 30, and the anode 20 are laminated in this order. In this case, peeling of the cathode 40 from the support 10, peeling of the electrolyte layer 30 from the cathode 40, and peeling of the anode 20 from the electrolyte layer 30 can be suppressed.

DESCRIPTION OF SYMBOLS 10 Support body 11 Hole 20 Anode 21 Anode constituent material 22 Anode temporary sintered body 30 Electrolyte layer 31 Electrolyte layer constituent material 32 Electrolyte layer temporary sintered body 40 Cathode 41 Cathode constituent material 42 Cathode temporary sintered body 100 Fuel cell 200 Heat source

Claims (9)

A method of manufacturing a fuel cell comprising a first member and a second member,
Including a firing step of sintering the second member on the first member;
The method for manufacturing a fuel cell, comprising: a firing step in which the firing of the lower surface of the second member is preceded by the firing of the upper surface of the second member in the firing step.   2. The method of manufacturing a fuel cell according to claim 1, wherein the firing step includes a step of applying and sintering a second member constituting material constituting the second member on the first member a plurality of times. . The firing step includes
A pre-baking step of pre-sintering the second member constituent material under conditions where sintering is not completed;
A second member constituent material is further disposed on the presintered second member constituent material, and the presintered second member constituent material and the further disposed second member constituent material are sintered. The method for producing a fuel cell according to claim 2, further comprising a main firing step.   The method for producing a fuel cell according to claim 3, wherein a firing temperature in the temporary firing step is lower than a firing temperature in the main firing step.   2. The method of manufacturing a fuel cell according to claim 1, wherein, in the firing step, the temperature of the second member decreases in order from the lower surface to the upper surface.   6. The method of manufacturing a fuel cell according to claim 5, wherein, in the firing step, a heat source is disposed on the opposite side of the first member to the second member.   The fuel cell manufacturing method according to claim 1, wherein the first member is an electrode, and the second member is a solid oxide electrolyte.   The method for producing a fuel cell according to claim 1, wherein the first member is a porous base material, and the second member is an electrode containing a solid oxide.   The fuel cell manufacturing method according to claim 1, wherein the first member is a solid oxide electrolyte, and the second member is an electrode containing a solid oxide.

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