JP2009231104A - Method for manufacturing fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a fuel cell, wherein the interfacial delamination between a hydrogen separation film and an electrolyte film at the time of power generation can be suppressed. <P>SOLUTION: The method for manufacturing a fuel cell includes a hydrogen treatment step of performing the hydrogen treatment for a hydrogen separation film-electrolyte film junction (10) where an electrolyte film (14) having the proton conductivity is provided on a hydrogen separation film (12) for transmitting the hydrogen in a state of proton and/or hydrogen atom prior to power generation of the hydrogen separation film-electrolyte film junction. The method for manufacturing the fuel cell suppresses the delamination between the hydrogen separation film and the electrolyte film during power generation or after power generation because a stress between the hydrogen separation film and the electrolyte film has been relaxed prior to power generation. As a result, degradation in the power generation performance of the fuel cell is suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

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.

  Among the fuel cells, those using solid electrolytes include solid polymer fuel cells, solid oxide fuel cells, hydrogen separation membrane cells, and the like. Here, the hydrogen separation membrane battery is a fuel cell provided with a dense hydrogen separation membrane. A dense hydrogen separation membrane is a membrane formed of a hydrogen-permeable metal that permeates hydrogen in the state of protons and / or hydrogen atoms. The dense hydrogen separation membrane functions not only as a support substrate for the electrolyte membrane but also as an anode during power generation.

  Patent Document 1 discloses a technique for suppressing delamination between a hydrogen separation metal layer and an electrolyte layer accompanying expansion of the hydrogen separation metal layer during hydrogen permeation.

WO2004-084333

  However, in the technique of Patent Document 1, when the fuel cell is exposed to a power generation atmosphere, there is a possibility that separation occurs between the hydrogen separation metal layer and the electrolyte layer.

  An object of this invention is to provide the manufacturing method of the fuel cell which can suppress the interface peeling of the hydrogen separation membrane and electrolyte membrane at the time of electric power generation.

  The fuel cell manufacturing method according to the present invention is directed to a hydrogen separation membrane-electrolyte membrane assembly in which an electrolyte membrane having proton conductivity is provided on a hydrogen separation membrane that transmits hydrogen in the state of protons and / or hydrogen atoms. And a hydrogen treatment step of performing a hydrogen treatment before the power generation of the hydrogen separation membrane-electrolyte membrane assembly. According to the fuel cell manufacturing method of the present invention, since the stress between the hydrogen separation membrane and the electrolyte membrane is relaxed before power generation, the hydrogen separation membrane and the electrolyte membrane are separated from each other during or after power generation. Is suppressed. As a result, a decrease in power generation performance of the fuel cell is suppressed.

  In the above manufacturing method, the hydrogen treatment may be a treatment in which a heat treatment is performed on the hydrogen separation membrane-electrolyte membrane assembly in a hydrogen-containing atmosphere. The manufacturing method may further include a step of forming a cathode on the opposite side of the electrolyte membrane from the hydrogen separation membrane before the hydrogen treatment step. According to this manufacturing method, even if stress is applied to the hydrogen separation membrane-electrolyte membrane assembly during the formation of the cathode, the stress is relieved by the hydrogen treatment. Therefore, by performing the hydrogen treatment after the formation of the cathode, the stress between the hydrogen separation membrane and the electrolyte membrane is further relaxed.

In the above manufacturing method, the hydrogen separation membrane may be made of palladium. In the above manufacturing method, the electrolyte membrane may be made of SrZn _(1-X) In _X O ₃ .

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the fuel cell which can suppress the interface peeling of the hydrogen separation membrane and electrolyte membrane at the time of electric power generation can be provided.

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

(First embodiment)
A method for manufacturing a fuel cell according to the first embodiment of the present invention will be described. FIG. 1A to FIG. 1C are flowcharts showing a fuel cell manufacturing method according to the first embodiment. First, as shown in FIG. 1A, a hydrogen separation membrane-electrolyte membrane assembly 10 is prepared. The hydrogen separation membrane-electrolyte membrane assembly 10 is obtained by providing an electrolyte membrane 14 having proton conductivity on a hydrogen separation membrane 12 made of a hydrogen permeable metal that permeates hydrogen in the state of protons and / or hydrogen atoms. is there.

  As the hydrogen permeable metal constituting the hydrogen separation membrane 12, for example, a metal such as Pd (palladium), V (vanadium), Ta (tantalum), Nb (niobium), or an alloy thereof can be used. Further, a hydrogen separation membrane 12 in which a film of Pd, Pd alloy or the like having hydrogen dissociation ability is formed on the surface of the two surfaces of the hydrogen permeable metal layer on which the electrolyte membrane 14 is provided is used. May be. The thickness of the hydrogen separation membrane 12 is not particularly limited, but is, for example, about 5 μm to 100 μm. The hydrogen separation membrane 12 may be a self-supporting membrane or may be supported by a porous base metal plate.

A proton conductive electrolyte is used as the electrolyte membrane 14. For example, perovskite electrolyte (SrZn _(1-X) In _X O ₃ etc.), pyrochlore electrolyte (Ln ₂ Zr ₂ O ₇ (Ln: La (lanthanum), Nd (neodymium), Sm (samarium) etc.)), Monazite type rare earth orthophosphate electrolyte (LnPO ₄ (Ln: La, Pr (praseodymium), Nd, Sm, etc.)), Zenitype type rare earth orthophosphate electrolyte (LnPO ₄ (Ln: La, Pr, Nd, Sm, etc.)) , Rare earth metaphosphate electrolyte (LnP ₃ O ₉ (Ln: La, Pr, Nd, Sm, etc.)), rare earth oxyphosphate electrolyte (Ln ₇ P ₃ O ₁₈ (Ln: La, Pr, Nd, Sm, etc.)) Or the like can be used for the electrolyte membrane 14. Although the film thickness of the electrolyte membrane 14 is not specifically limited, For example, it is about 1 micrometer.

  Next, as shown in FIG. 1B, the hydrogen separation membrane-electrolyte membrane assembly 10 prepared in FIG. 1A is subjected to hydrogen treatment. The hydrogen treatment refers to a treatment in which heat treatment is performed on the hydrogen separation membrane-electrolyte membrane assembly 10 in a hydrogen-containing atmosphere. The hydrogen-containing atmosphere in this case is not particularly limited, but has a hydrogen partial pressure of, for example, about 50 kPa to 120 kPa. The temperature of the hydrogen separation membrane-electrolyte membrane assembly 10 at the time of heat treatment is not particularly limited, but may be within a predetermined temperature range including a temperature (for example, about 400 ° C.) when power is generated as a fuel cell. . As an example, the temperature of the hydrogen separation membrane-electrolyte membrane assembly 10 may be maintained at about 350 ° C. to 500 ° C. The hydrogen treatment time is not particularly limited, but may be about 0.2 hr to 2.0 hr.

  When the hydrogen treatment is executed, a hydrogen atmosphere acts and stress is applied to the electrolyte membrane 14. On the other hand, in the hydrogen atmosphere, the hydrogen permeable metal of the hydrogen separation membrane 12 becomes easy to move with time. Thereby, the stress between the hydrogen separation membrane 12 and the electrolyte membrane 14 is relaxed.

Subsequently, as shown in FIG. 1C, the cathode 20 is formed on the electrolyte membrane 14 of the hydrogen separation membrane-electrolyte membrane assembly 10. As the cathode 20, for _example, it can be used _{La 0.6 Sr 0.4 CoO 3, La} 0.5 Sr 0.5 MnO 3, La 0.5 Sr 0.5 FeO 3 or the like ceramics. The cathode 20 can be formed by, for example, PVD.

  The fuel cell 30 is manufactured by the above method. In the fuel cell 30, the hydrogen separation membrane 12 functions as a support for supporting and reinforcing the electrolyte membrane 14 and also functions as an anode. A plurality of fuel cells 30 may be stacked to constitute a fuel cell stack.

  The fuel cell 30 generates power by the following action. First, a fuel gas containing hydrogen is supplied to the hydrogen separation membrane 12. Hydrogen in the fuel gas passes through the hydrogen separation membrane 12 in the state of protons and / or hydrogen atoms and reaches the electrolyte membrane 14. The hydrogen atoms that have reached the electrolyte membrane 14 are dissociated into protons and electrons. Protons pass through the electrolyte membrane 14 and reach the cathode 20. The electrons are conducted through the hydrogen separation membrane 12 and pass through an external circuit (not shown) that electrically connects the hydrogen separation membrane 12 and a load (not shown) such as a motor and an auxiliary machine to the cathode 20. Supplied to the cathode 20 side.

  On the other hand, an oxidant gas containing oxygen is supplied to the cathode 20. In the cathode 20, water is generated from oxygen in the oxidant gas, protons conducted through the electrolyte membrane 14, and electrons supplied through an external circuit. With the above operation, power generation by the fuel cell 30 is performed. During power generation, the fuel cell 30 generates heat due to reaction heat. As a result, the temperature of the fuel cell 30 is about 400 ° C.

  According to the fuel cell manufacturing method of the present embodiment, since the stress between the hydrogen separation membrane 12 and the electrolyte membrane 14 is relaxed before power generation, the hydrogen separation membrane 12 during power generation or after power generation Separation from the electrolyte membrane 14 is suppressed. Thereby, a decrease in power generation performance of the fuel cell 30 is suppressed.

  Note that a hydrogen atmosphere acts on the hydrogen separation membrane-electrolyte membrane assembly 10 also during power generation. Therefore, it is conceivable to relieve stress between the hydrogen separation membrane 12 and the electrolyte membrane 14 during power generation without performing hydrogen treatment in advance. However, since oxygen is supplied in addition to hydrogen during power generation, oxygen may enter between the hydrogen separation membrane 12 and the electrolyte membrane 14 when stress is applied to the electrolyte membrane 14. In this case, there is a possibility that peeling between the hydrogen separation membrane 12 and the electrolyte membrane 14 is induced by combustion of hydrogen and oxygen.

  Compared to this, in the manufacturing method according to the present embodiment, the hydrogen treatment is performed in a state where air is not supplied to the cathode 20. Therefore, it is not affected by the combustion of hydrogen and oxygen. As a result, peeling between the hydrogen separation membrane 12 and the electrolyte membrane 14 can be suppressed.

  Note that a hydrogen permeation treatment may be performed in advance on the hydrogen separation membrane 12 before the electrolyte membrane 14 is formed. In this case, the electrolyte membrane 14 can be formed after the hydrogen separation membrane 12 is deformed in advance. In this case, peeling of the hydrogen separation membrane 12 and the electrolyte membrane 14 during or after power generation of the fuel cell 30 is further suppressed.

  Here, even if the hydrogen separation membrane-electrolyte membrane assembly 10 is not subjected to hydrogen treatment, the hydrogen separation membrane 12 and the electrolyte membrane 14 can be obtained only by performing hydrogen permeation treatment on the hydrogen separation membrane 12 before the formation of the electrolyte membrane 14. It is considered that peeling of the film is sufficiently suppressed. However, when the electrolyte membrane 14 is formed, hydrogen in the hydrogen separation membrane 12 is removed due to the influence of the atmosphere, temperature, etc. Therefore, when the hydrogen separation membrane-electrolyte membrane assembly 10 is exposed to a hydrogen atmosphere, hydrogen separation is performed again. The film 12 may be deformed. In this case, the hydrogen separation membrane 12 and the electrolyte membrane 14 may be peeled off. Therefore, the separation of the hydrogen separation membrane 12 and the electrolyte membrane 14 can be further suppressed by performing the hydrogen treatment on the hydrogen separation membrane-electrolyte membrane assembly 10 as in the present embodiment.

(Second Embodiment)
Then, the manufacturing method of the fuel cell which concerns on the 2nd Embodiment of this invention is demonstrated. FIG. 2A and FIG. 2B are flowcharts showing a method of manufacturing a fuel cell according to the second embodiment. First, as shown in FIG. 2A, a fuel cell 30a is prepared. The fuel cell 30 a is a hydrogen separation membrane cell in which the cathode 20 is formed on the electrolyte membrane 14 of the hydrogen separation membrane-electrolyte membrane assembly 10.

  Next, as shown in FIG. 2B, hydrogen treatment is performed on the fuel cell 30a. The hydrogen treatment is performed by the same method as the hydrogen treatment described with reference to FIG.

  Also in the fuel cell manufacturing method according to the present embodiment, the stress between the hydrogen separation membrane 12 and the electrolyte membrane 14 is relieved. Thereby, peeling of the hydrogen separation membrane 12 and the electrolyte membrane 14 during or after power generation of the fuel cell 30a is suppressed. In the present embodiment, even if stress is applied to the hydrogen separation membrane-electrolyte membrane assembly 10 when the cathode 20 is formed, the stress is relieved by the hydrogen treatment. Therefore, by performing the hydrogen treatment after the formation of the cathode 20, the stress between the hydrogen separation membrane 12 and the electrolyte membrane 14 is further relaxed.

  Hereinafter, the characteristics of the fuel cell manufactured by the manufacturing method according to the above embodiment were examined.

Example 1
In Example 1, a fuel cell 30a was manufactured according to the manufacturing method according to the second embodiment. Palladium was used as the hydrogen separation membrane 12. SrZn _(1-X) In _X O ₃ was used as the electrolyte membrane 14. As the cathode 20, La _0.6 Sr _0.4 CoO ₃ was used. First, the fuel cell 30a was heated to 400 ° C. in an air atmosphere and subjected to hydrogen treatment for 0.5 hours in a hydrogen atmosphere of 50 kPa to 120 kPa. Thereafter, the hydrogen separation membrane 12 was exposed to a hydrogen atmosphere, and the cathode 20 was exposed to air.

(Comparative Example 1)
In Comparative Example 1, no hydrogen treatment was performed on the fuel cell 30a. Others are the same as in the first embodiment.

(analysis)
FIG. 3A is a photograph of the fuel cell according to Example 1 viewed from the hydrogen separation membrane side. FIG. 3B is a photograph of the fuel cell according to Comparative Example 1 viewed from the hydrogen separation membrane side. As shown in FIG. 3B, in the fuel cell according to Comparative Example 1, a large number of peelings occurred. On the other hand, in the fuel cell according to Example 1, there was little peeling. Therefore, it was found that peeling is suppressed by performing hydrogen treatment before exposing the fuel cell to the power generation atmosphere.

FIG. 1A to FIG. 1C are flowcharts showing a fuel cell manufacturing method according to the first embodiment. FIG. 2A and FIG. 2B are flowcharts showing a method of manufacturing a fuel cell according to the second embodiment. FIG. 3A is a photograph of the fuel cell according to Example 1 viewed from the hydrogen separation membrane side. FIG. 3B is a photograph of the fuel cell according to Comparative Example 1 viewed from the hydrogen separation membrane side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydrogen separation membrane-electrolyte membrane assembly 12 Hydrogen separation membrane 14 Electrolyte membrane 20 Cathode 30 Fuel cell

Claims (5)

  In contrast to a hydrogen separation membrane-electrolyte membrane assembly in which an electrolyte membrane having proton conductivity is provided on a hydrogen separation membrane that permeates hydrogen in the state of protons and / or hydrogen atoms, the hydrogen separation membrane-electrolyte membrane assembly A method for producing a fuel cell, comprising a hydrogen treatment step of performing hydrogen treatment before power generation.   2. The method of manufacturing a fuel cell according to claim 1, wherein the hydrogen treatment is a treatment in which heat treatment is performed on the hydrogen separation membrane-electrolyte membrane assembly in a hydrogen-containing atmosphere.   3. The method of manufacturing a fuel cell according to claim 1, further comprising a step of forming a cathode on the opposite side of the electrolyte membrane from the hydrogen separation membrane before the hydrogen treatment step.   The method for producing a fuel cell according to claim 1, wherein the hydrogen separation membrane is made of palladium. The method for manufacturing a fuel cell according to claim ₁ , wherein the electrolyte membrane is made of SrZn _(1-X) In _X O ₃ .

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