JP2005222843A - Manufacturing method of fuel cell and electrolyte film for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance practicality of an electrolyte film composed of a hydrogen separation film layer and an electrolyte film layer containing an oxygen-deficient type proton conductive compound. <P>SOLUTION: The electrolyte film 100 laid between an oxygen electrode 20 and a hydrogen electrode 30 is formed by sandwiching an electrolyte film layer 110 between a dense hydrogen separation film layer 120 and an oxygen electrode side film layer 125 formed into a thin film. The electrolyte film layer 110 is formed into a film by using a proton conductive compound of a perovskite structure, and exerts a proton conductive property in a state that an oxygen atom is introduced in an inter-lattice oxygen deficiency. Although the oxygen electrode side film layer 125 is formed into a film by using a proton conductive compound of a perovskite structure, its oxygen ion conductivity is small, and consequently, its transport number of oxygen ion also becomes small, so that it exerts proton conductivity sufficient for practical use as an electrolyte film 100 constructing member. Further, the oxygen electrode side film layer 125 prevents or restrains escape of the oxygen already introduced in the inter-lattice oxygen deficiency by being covered by the electrolyte film layer 110. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell, and more specifically, a fuel cell in which an electrolyte membrane is composed of a hydrogen separation membrane layer that selectively permeates hydrogen and an electrolyte membrane layer of an oxygen-deficient proton conductor compound; It relates to a manufacturing method.

  A fuel cell receives supply of gas, for example, hydrogen gas and oxygen gas, at both electrodes sandwiching an electrolyte membrane, and generates power. When supplying such hydrogen gas, it is desirable to supply high-purity hydrogen in view of the progress of the electrode reaction, and various proposals have been made. As one of the techniques, it has been proposed to provide a hydrogen separation membrane layer having a property of selectively permeating hydrogen in the electrolyte membrane on the side of the hydrogen electrode to which hydrogen is supplied (for example, Patent Document 1).

JP-A-5-299105

  In the above-mentioned patent document, an electrolyte membrane in which a hydrogen separation membrane layer is bonded to a perfluorosulfonic acid type ion exchange membrane having proton conductivity is proposed in the embodiment. In such a fuel cell, the material of the hydrogen separation membrane layer is a metal, and the ion exchange membrane is a polymer resin. In the polymer resin film formation technique, the film thickness is limited, and the film thickness is thicker than the metal film formation technique. For this reason, the membrane resistance due to the film thickness is increased and the internal resistance of the fuel cell is likely to increase. Therefore, in order to improve the performance of the battery performance, the electrolyte membrane to which the thin hydrogen separation membrane layer is bonded is made thinner. It is desirable to plan.

  Examples of electrolyte raw materials having proton conductivity that can be thinned by the same film forming technique as the hydrogen separation membrane layer include perovskite proton conductor compounds and similar compounds. If a thin film of such a compound is used as the electrolyte membrane layer, since it is a thin film, the internal resistance can be reduced as well as the reduction of the membrane resistance, and the battery performance can be improved. However, these compounds exhibit proton-conducting properties when oxygen atoms are introduced into interstitial oxygen vacancies, so even if they are used in combination with hydrogen separation membrane layers, they can be improved in practical use. There is room for.

  The present invention has been made to solve the above-described problems, and an object thereof is to improve the practicality of an electrolyte membrane including a hydrogen separation membrane layer and an oxygen-deficient proton conductor compound electrolyte membrane layer.

  In order to solve at least a part of such problems, the fuel cell of the present invention is disposed between both the hydrogen electrode that receives the supply of the hydrogen-containing fuel gas and the oxygen electrode that receives the supply of the oxygen-containing oxygen gas. An electrolyte membrane is provided to be joined to both electrodes. For this electrolyte membrane, a hydrogen separation membrane layer on the hydrogen electrode side that selectively permeates hydrogen, an electrolyte membrane layer formed on the surface of the hydrogen separation layer, and an electrolyte membrane layer so as to be located on the oxygen electrode side In addition, the electrolyte membrane layer exhibits proton-conducting properties in a state in which oxygen atoms are introduced into interstitial oxygen deficiencies. The electrolyte membrane layer was formed on the surface of the hydrogen separation layer with an oxygen deficient proton conductor compound. On the other hand, for the oxygen electrode side membrane layer covering this electrolyte membrane layer, it exhibits proton conduction properties and suppresses oxygen atom escape from the electrolyte membrane layer due to the property of suppressing the movement of oxygen atoms in the membrane layer. It was assumed to exhibit the property to do.

  In the electrolyte membrane layer of oxygen-deficient proton conductor compound, it cannot be determined that oxygen atoms that have already been introduced into interstitial oxygen vacancies exist, and the oxygen atom introduction reaction into interstitial oxygen vacancies occurs reversibly. It is known. In other words, it is known that oxygen atoms enter and leave interstitial oxygen vacancies depending on the gas atmosphere (for example, oxygen deficiency), temperature, potential, and the like.

  Therefore, paying attention to the possibility that such oxygen atoms can enter and exit, in the fuel cell of the present invention, the electrolyte membrane layer is sandwiched between the hydrogen separation membrane layer and the oxygen electrode side membrane layer to cover both surfaces of the electrolyte membrane layer. This prevents or suppresses the release of oxygen atoms introduced into interstitial oxygen vacancies in the electrolyte membrane layer. Therefore, in the electrolyte membrane layer, the state in which oxygen atoms are introduced into interstitial oxygen vacancies can be maintained, so that the property of proton conduction in the electrolyte membrane layer is not significantly impaired. In addition, since the oxygen electrode side membrane layer exhibits the property of proton conduction, the function as an electrolyte membrane in which proton conductivity is indispensable is not impaired. Therefore, it is possible to improve the practicality when an electrolyte membrane using a hydrogen separation membrane layer and an oxygen-deficient proton conductor compound electrolyte membrane layer in combination is used in a fuel cell.

As a material for forming the hydrogen separation membrane layer, noble metals such as palladium and palladium alloys, and VA group elements such as vanadium (V), niobium (Nb), and tantalum (Ta) can be used. The hydrogen separation membrane layer exhibits the property of selectively permeating hydrogen. As a material for forming the electrolyte membrane layer, a perovskite proton conductor compound (for example, BaCeO ₃ , SrCeO ₃ , SrZrO ₃ , CaZrO _3, etc.) or a pyrochlore proton conductor compound (for example, Gd ₂ Ti _2). O ₇ system, La ₂ Zr ₂ O ₇ system, etc.) can be used. The electrolyte membrane layer formed from these proton conductor compounds exhibits the property of proton conduction in a state where oxygen atoms are introduced into interstitial oxygen defects.

Examples of the material for forming the oxygen electrode side membrane layer include proton conductors that exhibit only proton conductivity such as CsHSO ₄ and do not have oxygen ion conductivity, protons such as WO ₃ that have both proton conductivity and electron conductivity. In addition to an electron conductor, an oxygen-deficient proton conductor compound having both proton conductivity and oxygen ion conductivity and exhibiting proton conductivity in terms of ion transport number can be used. In this case, when an oxygen-deficient proton conductor compound is used for forming the oxygen electrode side membrane layer, prevention or suppression of oxygen atoms already introduced into interstitial oxygen vacancies in the electrolyte membrane layer covered with the oxygen electrode side membrane layer is prevented. From this point, an oxygen deficient proton conductor compound having an oxygen ion conductivity smaller than that of the oxygen deficient proton conductor compound forming the electrolyte membrane layer is used for forming the oxygen electrode side membrane layer.

For example, if BaCeO ₃ , SrCeO ₃ , SrZrO ₃ , and CaZrO ₃ ceramics are selected as the perovskite proton conductor compound, these ceramics have low oxygen ion conductivity in this order. become. If the electrolyte membrane layer is formed of a BaCeO ₃ based ceramic, the oxygen electrode side membrane layer may be formed of a SrCeO ₃ based, SrZrO ₃ based, or CaZrO ₃ based ceramic. Similarly, if the electrolyte membrane layer is a SrCeO ₃ based ceramic, the oxygen electrode side membrane layer is a SrZrO ₃ based or CaZrO ₃ based ceramic, and the electrolyte membrane layer is a SrZrO ₃ based ceramic, The layer may be a CaZrO ₃ based ceramic. And the electrolyte membrane layer formed from these compounds exhibits the property of proton conduction, and suppresses the escape of oxygen atoms from the electrolyte membrane layer due to the property of suppressing the movement of oxygen atoms in the membrane layer.

  The above-described fuel cell of the present invention can take various forms. For example, a through-hole penetrating the layer is formed in the oxygen electrode side membrane layer, and the electrolyte membrane layer is formed as an oxygen electrode in the hole range of the through-hole. It can also be exposed to. By so doing, the region where oxygen can escape from the electrolyte membrane layer is limited, and accordingly, it is possible to prevent or suppress the escape of oxygen atoms already introduced into interstitial oxygen vacancies in the electrolyte membrane layer. In addition, even if oxygen atoms already introduced into the interstitial oxygen vacancies in the electrolyte membrane layer occur in the through hole region, oxygen atoms can be injected into the interstitial oxygen vacancies through the through holes. It is also possible to compensate for the loss of oxygen.

  When such oxygen atoms are implanted, the degree of escape of oxygen atoms introduced into interstitial oxygen vacancies in the electrolyte membrane layer is estimated, and when the degree of escape of introduced oxygen atoms is estimated to increase, from the oxygen electrode side Oxygen is replenished to the electrolyte membrane layer through the through-hole, and the escape of oxygen atoms introduced into interstitial oxygen vacancies can be compensated.

  In this case, an estimation method based on the transition (decrease) in the temperature of the fuel cell or the environmental temperature is simple as a method for estimating that the degree of oxygen atoms introduced into interstitial oxygen vacancies in the electrolyte membrane layer has increased. . Moreover, it can also be performed as follows.

  The degree of escape of oxygen atoms introduced into interstitial oxygen vacancies in the electrolyte membrane layer affects the degree of proton conductivity. When proton conductivity changes, the power generation status, membrane resistance, and internal resistance also change. Therefore, the above estimation can also be performed based on the power generation status (specifically, output current transition) and internal resistance transition. In such estimation, the estimation can be performed in consideration of the fuel cell temperature.

In addition, the procedure adopted by the present invention to produce an electrolyte membrane that is disposed between a hydrogen electrode and an oxygen electrode of a fuel cell and joined to both electrodes,
Forming a hydrogen separation membrane layer having a property of selectively permeating hydrogen (1);
(2) forming an electrolyte membrane layer on the surface of the hydrogen separation layer using an oxygen-deficient proton conductor compound that exhibits proton conduction properties in a state where oxygen atoms are introduced into interstitial oxygen defects; ,
A step (3) of forming a coating film layer on the surface of the electrolyte membrane layer using a compound having a property of proton conduction and a property of limited movement of oxygen atoms,
The step (3) of forming the coating film layer is performed in a state where the electrolyte membrane layer is in a state where oxygen atoms are introduced into the interstitial oxygen vacancies.

  By doing so, a highly practical electrolyte membrane using both the hydrogen separation membrane layer and the oxygen-deficient proton conductor compound electrolyte membrane layer can be easily produced.

  In such a manufacturing method, in forming a coating film layer, as a compound used for forming the coating film layer, an oxygen-deficient type that exhibits proton conduction properties in a state in which oxygen atoms are introduced into interstitial oxygen defects An oxygen deficient proton conductor compound having a lower oxygen ion conductivity than the oxygen deficient proton conductor compound forming the electrolyte membrane layer can be used. By doing so, the electrolyte membrane layer and the coating membrane layer can be formed of the same compound, so that almost the same film formation method can be taken.

  In forming the electrolyte membrane layer, the hydrogen separation layer is disposed in a chamber, and the electrolyte membrane layer is formed on the surface of the hydrogen separation layer using the oxygen-deficient proton conductor compound, In forming the coating film layer, the inside of the chamber used for forming the electrolyte film layer is placed in an environment where the oxygen partial pressure is higher than that during the electrolyte film formation, so that the electrolyte film layer becomes deficient in the interstitial oxygen. It is also possible to form the coating film layer on the surface of the electrolyte membrane layer using the compound under the condition that oxygen atoms are introduced.

  Alternatively, in forming the coating film layer, oxygen atoms are injected into the electrolyte membrane layer from the surface of the membrane so that the electrolyte membrane layer is introduced with oxygen atoms into the interstitial oxygen deficiency. The coating film layer can be formed on the surface of the electrolyte membrane layer using the compound.

  Further, a coating film layer is formed on the surface of the electrolyte membrane layer so that a partial region of the surface of the electrolyte membrane layer is exposed, and then oxygen atoms are transferred from the membrane surface of the exposed region to the electrolyte membrane layer. Inject. Then, by this oxygen element implantation, the electrolyte membrane layer can be placed in a state where oxygen atoms are introduced into interstitial oxygen vacancies to cover the exposed region.

  If these methods are taken, the oxygen escape can be suppressed or prevented more easily and reliably in a state where the proton conductivity of the electrolyte membrane layer is expressed.

  Next, embodiments of the fuel cell according to the present invention will be described based on examples. FIG. 1 is an explanatory view schematically showing a cross section of a cell constituting the fuel cell 10 of the embodiment. This cell has a structure in which an electrolyte membrane 100 is sandwiched between an oxygen electrode 20 (cathode) and a hydrogen electrode 30 (anode). The oxygen electrode 20 and the hydrogen electrode 30 can be formed of various conductive materials such as platinum, and include an oxygen channel 22 and a hydrogen channel 32, respectively, as shown.

  The electrolyte membrane 100 is located on the oxygen electrode 20 side, a dense hydrogen separation membrane layer 120 formed as a thin film using vanadium (V), an electrolyte membrane layer 110 formed as a thin film using a solid oxide on the surface thereof, and the oxygen electrode 20 side. And an oxygen-electrode-side film layer 125 formed on the surface of the electrolyte film layer using an oxide. The hydrogen separation membrane layer 120 exhibits the property of selectively permeating hydrogen due to the characteristics of vanadium as a film forming material, and is located on the hydrogen electrode 30 side and joined to the electrode.

The electrolyte membrane layer 110 is formed using a BaCeO ₃ -based ceramic of a perovskite proton conductor compound, which is a typical example of an oxygen deficient proton conductor compound. Since it is a BaCeO ₃ ceramic thin film of a perovskite type proton conductor compound, which is a film-forming material, it exhibits proton conduction properties in a state where oxygen atoms are introduced into interstitial oxygen defects.

The oxygen electrode side membrane layer 125 is formed using a perovskite type proton conductor compound in the same manner as the electrolyte membrane layer 110. However, the oxygen electrode side membrane layer 125 is more oxygen ion than the BaCeO ₃ type ceramic that is a material for forming the electrolyte membrane layer 110. A perovskite proton conductor compound having a low transport number is used. That is, since the material for forming the electrolyte membrane layer 110 is a BaCeO ₃ -based ceramic, in this embodiment, the oxygen electrode side membrane layer 125 is formed of, for example, a SrCeO ₃ -based ceramic. In this case, SrZrO ₃ or CaZrO ₃ -based ceramics having an oxygen ion transport number smaller than that of the BaCeO ₃ -based material can also be used.

  Since the oxygen electrode side membrane layer 125 is a perovskite type proton conductor compound, it has both proton conductivity and oxygen ion conductivity. However, since the oxygen ion conductivity of the employed compound is small, the oxygen ion transport number is also small. . As a result, proton conductivity sufficient for practical use as a constituent member of the electrolyte membrane 100 for a fuel cell is exhibited.

In this case, the materials of the hydrogen separation membrane layer 120, the electrolyte membrane layer 110, and the oxygen electrode side membrane layer 125 are not limited to those described above. The hydrogen separation membrane layer 120 selectively transmits hydrogen. It is also possible to use noble metals such as palladium and palladium alloys that exhibit the properties to be used, and VA group elements such as niobium (Nb) and tantalum (Ta). For the electrolyte membrane layer 110, other perovskite proton conductor compounds exhibiting proton conduction properties in the state where oxygen atoms are introduced into interstitial oxygen defects, such as SrCeO ₃ , SrZrO ₃ , and CaZrO ₃ Or pyrochlore proton conductor compounds such as Gd ₂ Ti ₂ O ₇ -based and La ₂ Zr ₂ O ₇ -based ceramics may be used. The oxygen electrode side membrane layer 125 may have any oxygen ion conductivity smaller than that of the perovskite proton conductor compound or pyrochlore proton conductor compound used for the electrolyte membrane layer 110. As the oxygen ion conductivity of the film forming compound of the oxygen electrode side film layer 125 is smaller than that of the film forming compound of the electrolyte film layer 110, the oxygen that has escaped from the electrolyte film layer 110 passes through the oxygen electrode side film layer 125. This is preferable from the viewpoint of suppressing or preventing the escape of introduced oxygen from the electrolyte membrane layer 110.

  In order to promote the reaction at the hydrogen electrode 30 and the oxygen electrode 20 during the power generation process, a catalyst layer such as platinum (Pt) is usually provided in the cell. Although not shown, the catalyst layer can be provided between the electrolyte membrane 100, the oxygen electrode 20, and the hydrogen electrode 30, for example.

  As illustrated, air is supplied to the oxygen electrode 20 as a gas containing oxygen. A hydrogen-rich fuel gas is supplied to the hydrogen electrode 30. Hydrogen in the fuel gas is separated by the hydrogen separation membrane layer 120 and moves to the oxygen electrode side through the electrolyte membrane layer 110 and the oxygen electrode side membrane layer 125 having proton conductivity.

  Here, a manufacturing process of the electrolyte membrane 100 will be described. FIG. 2 is a process diagram for explaining a manufacturing process of the electrolyte membrane 100, and FIG. 3 is an explanatory diagram schematically showing a state of thin film formation. Since the electrolyte membrane layer 110, the oxygen electrode side membrane layer 125, and the hydrogen separation membrane layer 120 are all thin films, it is sufficient to apply an existing thin film forming method. For example, if the thickness of the electrolyte membrane layer 110 is 1 μm, the thickness of the oxygen electrode side membrane layer 125 is 0.1 μm, and the thickness of the hydrogen separation membrane layer 120 is about 40 μm, the following may be performed. In addition, the thickness of each layer can be set arbitrarily and is adjusted in the film forming process.

  First, the base material used as the hydrogen separation membrane layer 120 is formed (step S200). In forming this base material, a method suitable for forming a thin film having a thickness of about 40 μm of the hydrogen separation membrane layer 120, for example, a vapor phase growth method or a thin-wall forming method using the above metal or alloy such as vanadium (V), A substrate is formed.

  Next, this base material (hydrogen separation membrane layer 120) is placed on the set table 302 of the chamber 300 of the thin film forming apparatus, the inside of the chamber 300 is brought into an appropriate reduced pressure state, and then the electrolyte membrane layer 110 is placed on the surface of the base material. A film is formed (step S210). This thin film forming apparatus is configured to be able to form thin films of different materials by switching the film material supplied to the film forming apparatus 304. In addition, the thin film forming apparatus includes various methods suitable for the above-mentioned ceramic thin film formation, such as vapor phase growth (chemical vapor deposition, physical vapor deposition), sputtering, vacuum deposition, laser ablation, etc. The thin film can be formed by this method.

When forming the electrolyte membrane layer 110, a BaCeO ₃ -based ceramic as a material for forming the electrolyte membrane layer 110 is supplied to the film-forming device 304 to bring the chamber 300 into an appropriate pressure-reduced state, and then the thin film is formed to the above-described thickness. After the formation of the electrolyte membrane layer 110, oxygen or air is introduced into the chamber 300 at an appropriate pressure by an oxygen pressurization supply device 306 attached to the chamber 300, and the inside of the chamber is subjected to electrolyte deposition for a predetermined time. (Step S220).

  The deposited electrolyte membrane layer 110 introduces oxygen atoms into interstitial oxygen vacancies during the film formation process, but the introduction of oxygen atoms into interstitial oxygen vacancies is reversible. The degree is not necessarily high, and it is also expected that introduced oxygen is lost during the film forming process. However, in step S220, since the electrolyte membrane layer 110 is placed in an environment under a high oxygen partial pressure, introduction of oxygen atoms into the deficiency of interstitial oxygen occurs, and the oxygen ion transport number decreases and the proton transport number. And the proton conduction properties are reliably exhibited.

  In this way, in order to introduce oxygen atoms into interstitial oxygen vacancies in the electrolyte membrane layer 110 by setting the inside of the chamber 300 to a high oxygen partial pressure, the electrolyte membrane is supplied to the hydrogen separation membrane layer 120 and the electrolyte membrane layer 110 by the power source 308. A direct current potential may be applied so that the layer 110 side has a negative potential. In this way, since the electrolyte membrane layer 110 is exposed to oxygen under a high oxygen partial pressure and receives a negative voltage, the oxygen atoms are interstitial oxygen as negatively charged ions on the surface of the electrolyte membrane layer 110. Introduced into the defect. Therefore, oxygen atom introduction into interstitial oxygen deficiency becomes more active, and the electrolyte membrane layer 110 exhibits the property of proton conduction more reliably. If applying such a potential in combination with increasing the oxygen partial pressure, the time required for introducing oxygen atoms into interstitial oxygen defects can be shortened.

While the electrolyte membrane layer 110 is placed under a high oxygen partial pressure, the membrane material supplied to the film-forming device 304 is switched to the SrCeO ₃ -based ceramic that is the film-forming material of the oxygen electrode side membrane layer 125, and the electrolyte membrane layer The oxygen electrode side film layer 125 is formed on the surface of 110 to the above-described film thickness (step S230). Thus, the electrolyte membrane 100 in which the electrolyte membrane layer 110 is sandwiched between the hydrogen separation membrane layer 120 and the oxygen electrode side membrane layer 125 is completed. Then, the fuel cell 10 (cell) is completed by disposing the electrolyte membrane 100 between both the oxygen electrode 20 and the hydrogen electrode 30 as shown in FIG.

  In the fuel cell 10 of the present embodiment described above, the electrolyte membrane layer 110 is sandwiched between the dense hydrogen separation membrane layer 120 and the oxygen electrode side membrane layer 125 so that both surfaces of the electrolyte membrane layer 110 are hydrogenated. The separation membrane layer 120 and the oxygen electrode side membrane layer 125 were covered. Moreover, when the oxygen electrode side membrane layer 125 is deposited on the electrolyte membrane layer 110 that has been deposited on the hydrogen separation membrane layer 120, the electrolyte membrane layer 110 is placed under a higher oxygen partial pressure than when the electrolyte membrane is deposited. Thus, before the oxygen electrode side film layer 125 is formed, oxygen atoms are introduced into the interstitial oxygen vacancies in the electrolyte film layer 110, and then the oxygen electrode side film layer 125 is formed on the surface of the electrolyte film layer 110. To do.

  For this reason, since it is possible to prevent or suppress the introduction of oxygen atoms introduced into interstitial oxygen vacancies in the electrolyte membrane layer 110 constituting the electrolyte membrane 100, the electrolyte membrane layer 110 causes vacancy in interstitial oxygen. It is possible to reliably maintain the state in which oxygen atoms are introduced. Therefore, the oxygen ion transport number in the electrolyte membrane layer 110 is reduced, the hydrogen ion transport number is increased, and the proton conduction property in the electrolyte membrane layer 110 is not significantly impaired. Furthermore, since the introduction of oxygen atoms into interstitial oxygen vacancies is promoted in advance for the electrolyte membrane layer 110 prior to the formation of the oxygen electrode side membrane layer 125, the proton conduction property of the electrolyte membrane layer 110 is high. Can be reliably maintained with accuracy. On the other hand, since the oxygen electrode side membrane layer 125 exhibits the property of proton conduction depending on the selection of the forming material, the function as an electrolyte membrane in which proton conductivity is indispensable is not impaired. Therefore, in the fuel cell 10 of the present embodiment, the practicality of the electrolyte membrane 100 using both the hydrogen separation membrane layer 120 and the oxygen-deficient proton conductor compound electrolyte membrane layer 110 can be enhanced. Moreover, such an electrolyte membrane 100 can be easily manufactured.

  In this example, the oxygen electrode side membrane layer 125 located on the oxygen electrode 20 side is an oxygen deficient proton conductor compound that exhibits proton conduction properties in a state where oxygen atoms are introduced into interstitial oxygen defects. Although it is a thin film, since its oxygen ion conductivity is small, it is difficult for the introduced oxygen atoms to escape to interstitial oxygen defects. For this reason, since the property of proton conduction in the oxygen electrode side membrane layer 125 is not greatly impaired, the electrolyte membrane 100 can be practically used.

In the embodiment described above, when forming the oxygen electrode side membrane layer 125 (step S230), the membrane material is a proton conductor compound that exhibits only proton conductivity such as CsHSO ₄ and does not have oxygen ion conductivity, Only by using a proton / electron conductor compound having both proton conductivity and electron conductivity such as WO ₃ or an oxygen-deficient proton conductor compound having a smaller oxygen ion transport number than the electrolyte membrane layer 110 The oxygen electrode side membrane layer 125 made of a compound can be easily formed on the surface of the electrolyte membrane layer 110. And even if it is the oxygen-electrode side film | membrane layer 125 of these compounds, there can exist the effect mentioned above.

  Next, another embodiment will be described. FIG. 4 is a process diagram for explaining the manufacturing process of the second embodiment, and FIG. 5 is an explanatory view schematically showing the state of thin film formation in the manufacturing process of the second embodiment. This embodiment is different in that oxygen is injected from the surface of the electrolyte membrane layer 110 in place of the high oxygen partial pressure step in the manufacturing process of the embodiment described above.

  In other words, in the manufacturing process of the second embodiment, the base material to be the hydrogen separation membrane layer 120 (step S200) and the membrane formation of the electrolyte membrane layer 110 (step S210) are sequentially performed, and then applied to the electrolyte membrane layer 110. Oxygen implantation is performed (step S225). In this oxygen injection step, as shown in FIG. 5, plasma of oxygen or ozone is generated in the chamber 300 by the plasma generator 310, and the electrolyte membrane that has been formed on the surface of the hydrogen separation membrane layer 120 in step S210. Oxygen is implanted into the layer 110 from the film surface. Next, an oxygen electrode side membrane layer 125 is formed on the surface of the electrolyte membrane layer 110 (step S230), and the electrolyte membrane layer 110 is sandwiched between the hydrogen separation membrane layer 120 and the oxygen electrode side membrane layer 125 so as to sandwich the electrolyte membrane layer 110. The membrane 100 is manufactured.

  According to the manufacturing method of the present embodiment described above, oxygen is injected into the electrolyte membrane layer 110 by oxygen or ozone plasma prior to the formation of the oxygen electrode side membrane layer 125. Therefore, the electrolyte membrane layer 110 in which the introduction of oxygen atoms into interstitial oxygen vacancies is more reliably performed can be sandwiched between the hydrogen separation membrane layer 120 and the oxygen electrode side membrane layer 125 to form the electrolyte membrane 100. . For this reason, the state in which the introduction of oxygen atoms into the deficiency of interstitial oxygen has occurred can be more reliably maintained in the electrolyte membrane layer 110 constituting the electrolyte membrane 100. Therefore, since the proton conduction property of the electrolyte membrane layer 110 can be maintained high, practicality is further increased.

  In taking the above-described manufacturing steps, the electrolyte membrane layer 110 and the oxygen electrode side membrane layer 125 were formed in the same chamber 300, but the electrolyte membrane layer 110 was formed by another film forming apparatus. It is possible to set the hydrogen separation membrane layer 120 on which the electrolyte membrane layer 110 has been formed in a film forming apparatus for the oxygen electrode side membrane layer 125. In this case, the plasma generating device 310 may be attached to the film forming apparatus for the oxygen electrode side film layer 125.

  Next, an embodiment in which the structure of the oxygen electrode side film layer 125 and the film forming procedure / oxygen implantation method are different will be described. 6 is an explanatory view schematically showing a cross section of a fuel cell having another oxygen electrode side membrane layer 125, FIG. 7 is a process diagram showing a manufacturing process of the electrolyte membrane 100, and FIG. 8 is a through-hole formation performed in the manufacturing process. FIG. 9 is an explanatory view showing a state of through-hole formation in the oxygen electrode side film layer 125.

  As shown in the drawing, in this embodiment, the oxygen electrode side membrane layer 125 is provided with the through holes 126 penetrating through the membrane layer, and the through holes are closed with the filler 127. Since the total area of the through-hole 126 is sufficiently smaller than the total area of the oxygen electrode side membrane layer 125, even if proton conduction cannot be performed at the position where the through hole 126 is formed, the entire area can be seen from the oxygen electrode side membrane layer 125. For example, the proton conductivity of the membrane is not impaired. Therefore, the filler 127 may be a proton non-conductive material such as glass or ceramic, or a metal having proton conductivity. Note that, from the above-described area relationship, even if the filler 127 has oxygen ion conductivity, the prevention or suppression of oxygen ion loss obtained by covering the electrolyte membrane layer 110 with the oxygen electrode side membrane layer 125 is impaired. It is not a thing.

  The electrolyte membrane 100 having such an oxygen electrode side membrane layer 125 is manufactured as follows. As shown in FIG. 7, first, similarly to the previous embodiment, a base material to be the hydrogen separation membrane layer 120 is formed (step S200), and the perovskite type described above is formed on the surface of the base material (hydrogen separation membrane layer 120). The electrolyte membrane layer 110 of the proton conductor compound is formed by an appropriate method (step S210). Next, the oxygen electrode side membrane layer 125 is formed with a perovskite proton conductor compound having a smaller oxygen ion conductivity than the perovskite proton conductor compound of the electrolyte membrane layer 110 (step S240). In this film formation, as shown in FIG. 8, the electrolyte membrane layer 110 that has been formed on the substrate (hydrogen separation membrane layer 120) is pressed with tapered pressing legs 320 extending from a jig (not shown), In this state, the oxygen electrode side film layer 125 is formed by the method such as the vapor phase growth method described above. Then, since the oxygen electrode side film layer 125 is not formed at the place pressed by the pressing leg 320, the oxygen electrode side film layer 125 is removed by removing the pressing leg 320 after forming the oxygen electrode side film layer 125. A through-hole 126 is formed at the top. In addition, the formation position of this through-hole 126 is not restricted to the location corresponding to the oxygen flow path 22 as shown in FIG.

  Thereafter, oxygen is injected into the electrolyte membrane layer 110 (step S250). In this oxygen implantation step, oxygen or ozone plasma is generated in the chamber as described with reference to FIG. 5, and the bottom surface of the through-hole 126, that is, the exposed surface of the electrolyte membrane layer 110 (through-hole 126) is generated by the plasma. The oxygen is injected into the electrolyte membrane layer 110 from the opening region. Alternatively, as described in FIG. 3, oxygen is injected into the electrolyte membrane layer 110 from the exposed surface of the electrolyte membrane layer 110 (opening region of the through hole 126) by applying a potential in an environment under a high partial pressure of oxygen. You can also do it. Such oxygen implantation is also performed on the oxygen electrode side film layer 125. However, the oxygen electrode side film layer 125 has lower oxygen ion conductivity than the electrolyte film layer 110, and therefore the degree of oxygen injection. Is small and does not cause a significant decrease in proton conductivity. Note that if plasma irradiation is performed only on the portion where the through-hole 126 is formed and its periphery, the influence of oxygen implantation (decrease in proton conductivity) in the oxygen electrode side film layer 125 does not become a problem.

  Following such oxygen injection, the through-hole 126 is closed (step S260), and the electrolyte membrane 100 in which the electrolyte membrane layer 110 is sandwiched between the hydrogen separation membrane layer 120 and the oxygen electrode side membrane layer 125 is completed. When the through-hole 126 is closed, the pressing leg 320 may be lifted and removed, and molten glass or the like may be dropped onto the formation location of the through-hole 126 and then cured.

  Through the manufacturing process described above, the oxygen electrode side membrane layer 125 covers the electrolyte membrane layer 110 over the entire surface in a state where the through hole 126 is closed with the filler 127. Moreover, since the through-hole 126 provided for oxygen injection into the electrolyte membrane layer 110 is closed with the filler 127 that does not cause oxygen ion conduction, the oxygen electrode side membrane layer 125 manufactured in the above manufacturing process was used. Even the electrolyte membrane layer 110 can prevent or suppress the escape of oxygen atoms introduced into interstitial oxygen vacancies, and can exhibit high practicality.

  The through holes 126 provided for oxygen injection in the oxygen electrode side film layer 125 do not have to be scattered holes, and can take various forms such as a groove shape. FIG. 10 is an explanatory view for explaining another form of the through hole 126. As shown in the figure, a jig that presses the electrolyte membrane layer 110 when the oxygen electrode side membrane layer 125 is formed may have a grid-like pressing leg 322. In this way, through-holes 126 that are continuous in the form of a lattice are formed in the oxygen electrode-side film layer 125 that has been formed on the surface of the electrolyte membrane layer 110, and the continuous through-holes 126 are blocked by the filler 127. It will be.

  Next, an embodiment in which the through hole 126 is not partially blocked will be described. FIG. 11 is an explanatory diagram for explaining an example in which the through hole 126 is used for oxygen injection in the state of the fuel cell 10 in which the electrolyte membrane 100 is assembled and completed.

  In this fuel cell 10, the oxygen electrode side membrane layer 125 has a through hole 126 that is closed with a filler 127 and a through hole 126 that remains open (a non-closed through hole 126). In order to manufacture such an oxygen electrode side membrane layer 125, it is only necessary to prevent a part of the through holes 126 from being blocked by the filler 127 in step S260 described in FIG. In this case, all the through holes 126 can be left open. In the oxygen electrode side membrane layer 125, the non-blocking through hole 126 is made to coincide with the oxygen flow path 22 for the convenience of using the non-blocking through hole 126 for oxygen injection in the completed fuel cell 10 state. Yes.

  As described above, the fuel cell 10 includes a fuel cell in addition to the electrolyte membrane 100 having the electrolyte membrane layer 110 sandwiched between the oxygen electrode side membrane layer 125 and the hydrogen separation membrane layer 120, the oxygen electrode 20 and the hydrogen electrode 30. In addition to the control device 60 for performing power generation control and the like, the pump 40, the reforming device 50, the temperature sensor 62, the current sensor 64, the power source 70, and the switch 80 are included.

  The pump 40 supplies compressed air as a gas containing oxygen to the oxygen flow path 22 of the oxygen electrode 20. The reformer 50 reforms and generates hydrogen-rich fuel gas and supplies the gas to the hydrogen flow path 32 of the hydrogen electrode 30. Hydrogen in the fuel gas is separated by the hydrogen separation membrane layer 120 and moves to the oxygen electrode side through the electrolyte membrane layer 110.

  The control device 60 controls the operation of the fuel cell 10 through the control of the pump 40 and the reforming device 50 described above. When the switch 80 closes the circuit based on a control signal from the control device 60, the power source 70 has a negative electrode on the oxygen electrode 20 side between the oxygen electrode 20 and the hydrogen electrode 30 in each cell of the fuel cell 10. Apply a DC voltage as follows. Such voltage application is performed by the control device 60 in accordance with the sensor outputs of the temperature sensor 62 and the current sensor 64, which will be described later.

  The power source 70 is an external power source prepared separately from the fuel cell 10. If the fuel cell 10 of this embodiment is an on-vehicle device, a secondary battery included in the vehicle may be applied. Further, if the fuel cell 10 is incorporated in a stationary fuel cell power generation system, the DC power source 70 may be configured from the system power source.

  Next, operation control performed by the fuel cell 10 of the present embodiment will be described. FIG. 12 is a flowchart showing the contents of the oxygen escape suppression mode operation.

  This oxygen desorption suppression mode operation is repeatedly executed every predetermined time. However, since the oxygen desorption of the electrolyte membrane layer 110 is suppressed, the system having the fuel cell 10 (for example, It is desirable not only for the operation period of the vehicle, the fuel cell power generation system, etc.) but also for the non-operation period. First, the control device 60 senses the output status of the system ON / OFF switch and the like in addition to the temperature sensor 62 and the current sensor 64 (step S300), and based on the result, the interstitial oxygen deficiency in the electrolyte membrane layer 110 is detected. The degree of escape of introduced oxygen atoms is estimated (step S310), and it is determined whether or not oxygen atoms need to be introduced, that is, whether or not oxygen is lost (step S320).

Such estimation of oxygen loss can be performed by the following various methods.
<1> If the operation stop of the system having the fuel cell 10 (for example, a vehicle, a fuel cell power generation system, etc.) is continued, oxygen ions are not introduced from the oxygen electrode, so that the introduced oxygen escapes from the electrolyte membrane layer 110. obtain. Therefore, based on the sensor output transition of the temperature sensor 62, the elapsed time of the shutdown, and the like, when the system shutdown is continued, the degree of escape of oxygen atoms already introduced into the interstitial oxygen vacancy is high. presume.
<2> Moreover, since the internal resistance change of the fuel cell 10 is captured as a resistance change between the oxygen electrode 20 and the hydrogen electrode 30 of each cell, a very small potential is applied from the power source 70 between the two electrodes, The current transition is detected by the current sensor 64. If the current transition is associated with an increase in internal resistance, it is estimated that the degree of escape of oxygen atoms already introduced into interstitial oxygen vacancies is high. This estimation method is performed while the fuel cell 10 is not in operation because a potential is applied between both electrodes. In the estimation based on the above-described current transition, the estimation range may be given by the fuel cell temperature detected by the temperature sensor 62.
<3> If the detection temperature of the temperature sensor 62 and the detection current of the current sensor 64 are kept low with respect to the supply of hydrogen gas / oxygen gas, oxygen escape occurs in the electrolyte membrane layer 110 and proton conductivity is reduced. It is assumed that the function of the electrolyte membrane 100 is lowered and the function of the electrolyte membrane 100 is reduced (for example, an increase in internal resistance). Therefore, in such a case, it is estimated that the degree of escape of oxygen atoms introduced into interstitial oxygen vacancies is high.

  If it is estimated that the degree of escape of oxygen atoms introduced into interstitial oxygen vacancies is high in this way, in the subsequent step S330, oxygen implantation processing is performed and this routine is terminated. As this oxygen implantation treatment, the following treatment can be taken.

  While the electrolyte membrane 100 is not operating or at the start-up, hydrogen gas / oxygen gas is not supplied to the electrode or at a time when the gas supply for battery operation is prepared. is there. Therefore, when it is determined that there is oxygen depletion under such circumstances, the control device 60 drives and controls the pump 40 to supply oxygen (atmosphere) to the oxygen electrode 20 while switching the switch 80 to ON. A voltage is applied from the power source 70 between the electrode 20 and the hydrogen electrode 30 with the oxygen electrode side as a negative electrode. The oxygen supply / voltage application can be performed for a predetermined time, or can be continued until the integrated power applied from the power source 70 reaches a predetermined value, and then ended. It is not necessary to supply hydrogen gas to the hydrogen electrode 30 when supplying oxygen and applying voltage. At the time of starting the battery, after the oxygen supply / voltage application is completed, the control device 60 controls the supply of both hydrogen gas and oxygen gas to control the operation of the fuel cell 10.

  If the oxygen supply and voltage application described above are performed, the following phenomenon occurs in the fuel cell 10. The electrolyte membrane layer 110 on the oxygen electrode 20 side is exposed to oxygen in the oxygen gas in the opening region of the non-closed through-hole 126 without the filler 127 and receives a negative voltage. Therefore, in the electrolyte membrane layer 110, oxygen atoms are introduced (injected) into the interstitial oxygen vacancies as negatively charged ions from the surface of the open region of the non-blocking through-hole 126.

  Further, when the operation of the fuel cell 10 is stopped or continued, oxygen injection can be performed as follows. In this case, the control device 60 drives and controls the pump 40 to supply oxygen (atmosphere) to the oxygen electrode 20. At this time, since no hydrogen gas is supplied on the hydrogen electrode 30 side, the electrochemical reaction in the fuel cell 10 does not proceed and oxygen is not consumed. For this reason, in the oxygen electrode 20, the oxygen flow path 22 is filled with the pressurized oxygen gas, and compared with the case where the operation is stopped without such gas supply, the oxygen electrode 20 side. The oxygen partial pressure increases.

  As described above, when the operation of the fuel cell is stopped, the oxygen electrode 20 side continues in the period of the operation stop with a high oxygen partial pressure. That is, as described above, there is no consumption of oxygen due to power generation, and the oxygen gas supply system is a closed system. Therefore, as long as there is no gas leak, the situation of high oxygen partial pressure continues. Accordingly, since the electrolyte membrane layer 110 on the oxygen electrode 20 side is in contact with oxygen having a high oxygen partial pressure, the escape of oxygen atoms introduced into interstitial oxygen vacancies in the electrolyte membrane layer 110 is not occluded. Even if it occurs from the opening region of the through-hole 126, oxygen injection is attempted so as to compensate for the loss by oxygen under a high oxygen partial pressure. By this oxygen injection, oxygen atoms are introduced from the open region of the non-blocking through-hole 126 into interstitial oxygen deficiency, so that the oxygen ion conductivity is increased and the oxygen ion transport number is decreased, and vice versa. The transport number can be increased to maintain the property (degree) of proton conduction.

  Further, during the operation period (operation period) of the fuel cell 10, oxygen injection can be achieved as follows. During such an operation period, the control device 60 executes an operation control routine (not shown) that controls the operation of the fuel cell according to the load, and supplies hydrogen gas / oxygen gas to perform power generation control. In spite of such power generation, if it is determined in step S320 in FIG. 12 that there is oxygen loss, it is assumed that the battery temperature does not rise because power generation is slow relative to the gas supply. Therefore, in such a case, an instruction to add power generation is output so as to generate power exceeding the power generation required in the operation control routine, and the fuel cell 10 is added to generate power by obtaining the load. In this way, the following phenomenon can be obtained.

  Introduction of oxygen atoms into interstitial oxygen vacancies to exhibit proton conduction properties occurs by conduction of oxygen ions in the electrolyte membrane layer 110 of the oxygen-deficient proton conductor compound. In other words, the higher the oxygen ion conductivity, the more oxygen atoms are introduced into interstitial oxygen deficits, and the proton conduction property (degree) can be maintained. Since the oxygen ion conductivity has a positive correlation with the temperature, for example, when the fuel cell 10 is operated with a small amount of power generation and such an operation state continues, the temperature of the electrolyte membrane layer 110 does not rise, May remain low.

  In this case, since the electrolyte membrane layer 110 is at a low temperature, the oxygen ion conductivity in the electrolyte membrane layer 110 is lowered, and the introduction of oxygen atoms into interstitial oxygen vacancies does not proceed. Therefore, if oxygen atom introduction does not proceed in a situation where introduction of introduced oxygen atoms into interstitial oxygen vacancies occurs, oxygen ion transport number in which oxygen can move as ions in electrolyte membrane layer 110 increases. Since the hydrogen ion transport number that protons can move is small, it is expected that the property of proton conduction will deteriorate. Note that the situation where the introduction of introduced oxygen atoms into the deficiency of interstitial oxygen occurs here refers to the fact that the oxygen electrode side film layer 125 was formed on the electrolyte film layer 110, but the film formation error It can be caused by a defect.

  However, in the present embodiment, as described above, the power generation of the fuel cell 10 is added and executed, so that the electrolyte membrane layer 110 can be heated by such power generation. For this reason, as the temperature rises, oxygen atoms are introduced from the open region of the non-blocking through-hole 126 into the interstitial oxygen deficiency, so that the oxygen ion conductivity increases and the oxygen ion transport number decreases, and vice versa. Increases the hydrogen ion transport number. Therefore, according to the present embodiment in which oxygen injection is performed during operation of the fuel cell 10, the proton conduction property (degree) can always be maintained over the operation period of the fuel cell 10.

  In this case, the additional power generation of the fuel cell 10 can be, for example, uniformly added several percent to several tens of percent with respect to the current power generation state, and may be performed as follows. FIG. 13 is an explanatory view for explaining the state of power generation on the fuel cell 10 for suppressing oxygen loss during operation of the fuel cell.

  As shown in the figure, if the current power generation state is low, the increase rate can be set higher, and the increase rate can be reduced as the power generation state becomes higher. This has the following advantages.

  When the fuel cell 10 is actively generating power to cope with a high load or the like, the electrolyte membrane layer 110 is already at a high temperature, so that the introduction of oxygen atoms into the deficiency of interstitial oxygen is not blocked. As described above, the high proton conduction property can be maintained. Therefore, in such a case, it is preferable to reduce the rate of addition of power generation because the power generation of the fuel cell 10 will not be inadvertently increased. On the other hand, in the low power generation situation in which the electrolyte membrane layer 110 is expected to be at a low temperature as described above, the heating rate of the electrolyte membrane layer 110 is increased by increasing the rate of addition of power generation, and proton conduction can be achieved early. The property can be restored and maintained.

  When the increase rate is changed as described above, as shown by the dotted line in FIG. 13, the increase rate can be set to zero when higher than a predetermined power generation situation H0. That is, in this predetermined power generation situation H0, since the electrolyte membrane layer 110 is sufficiently hot, it is assumed that a high proton conduction property has already been developed, and the additional power generation is stopped. By doing so, the frequency of execution of the above-described additional power generation can be reduced according to the actual power generation situation, so that inadvertent consumption of hydrogen gas / oxygen gas can be suppressed and the system including the fuel cell 10 (vehicle or fuel cell power generation) System) will not cause an inadvertent decrease in efficiency.

  In this case, the power generation state H0 to be zero can be set to be large or small according to the sensor output of the temperature sensor 62. For example, if the temperature detected by the temperature sensor 62 is higher, it can be assumed that oxygen atoms are introduced into interstitial oxygen deficits, so the power generation status H0 is set to a small value. In this way, even if the actual power generation state is low, the above-described additional power generation is not necessary, and the frequency of execution thereof can be reduced, so that there is the above-described advantage.

  In addition, oxygen injection during a period in which the operation of the fuel cell 10 continues to be stopped can be performed by forced power generation. FIG. 14 is an explanatory diagram illustrating an example of a state of forced power generation for oxygen injection, and FIG. 15 is an explanatory diagram illustrating another example of a state of forced power generation.

  During the operation stop period of the fuel cell 10, the gas supply to the fuel cell 10 is originally stopped and no power generation is performed. However, the control device 60 performs forced power generation control during the operation stop continuation period. . Since this forced power generation is unnecessary for load operation or the like, if the vehicle is equipped with the fuel cell 10, as shown in FIG. It is only necessary to continuously generate a small amount of electricity of about% or less. Specifically, supply of hydrogen gas / oxygen gas to the oxygen electrode 20 and the hydrogen electrode 30 is controlled so as to generate such a small amount of power generation.

  Even in such a minute power generation, the temperature of the electrolyte membrane layer 110 can be increased during the power generation, so that the oxygen ion conductivity is increased as described above, and the opening of the non-blocking through-hole 126 is opened. Oxygen can be injected from the region, so that the property (degree) of proton conduction can be maintained even during the fuel cell shutdown period.

  Further, instead of forced micro power generation, it is possible to repeatedly stop and execute power generation as shown in FIG. When such power generation is repeated, as shown by pattern 1 and pattern 2 in the figure, various power generation amounts and power generation times can be used. Even if such power generation is repeated, the temperature of the electrolyte membrane layer 110 can be increased during the power generation, so that the property (degree) of proton conduction can be maintained even during the fuel cell shutdown period as described above. . In addition, since forced power generation may be performed periodically, excessive power generation operation becomes unnecessary, and inadvertent consumption of hydrogen gas or the like can be suppressed. The electromotive force obtained by repeating the power generation can be used, for example, for storage of a secondary battery.

  As mentioned above, although several Example of this invention was described, this invention is not limited to these Examples, Of course, it can implement with a various aspect in the range which does not deviate from the summary of this invention. For example, in order to inject oxygen from the open region of the non-closed through-hole 126, the voltage application between the oxygen electrode 20 and the hydrogen electrode 30 is assumed to be a constant voltage application, but can be modified as follows. FIG. 16 is an explanatory diagram for explaining a modification of voltage application for oxygen implantation.

  In the configuration shown in FIG. 11, the power supply 70 has a variable output voltage, or a variable resistor is incorporated in the circuit. Then, the control device 60 variably controls the output voltage up and down, and fluctuates the potential on the oxygen electrode 20 side up and down by controlling the variable resistance value up and down. In this way, the negative electrode potential applied to the oxygen electrode 20 changes as shown by the dotted line in FIG. When potential fluctuations occur in this manner, oxygen atom introduction into interstitial oxygen vacancies is expected to proceed actively due to the property that the oxygen atom introduction reaction into interstitial oxygen vacancies is also an electrochemical reaction. Therefore, the introduction of oxygen atoms from the opening region of the non-occluded through-hole 126 on the oxygen electrode 20 side under voltage application to the electrolyte membrane layer 110 is promoted, which is beneficial for maintaining the property of proton conduction in the electrolyte membrane layer 110. It is.

It is explanatory drawing which shows typically the cross section of the cell which comprises the fuel cell 10 of an Example. 5 is a process diagram for explaining a manufacturing process of the electrolyte membrane 100. FIG. It is explanatory drawing which shows the mode of thin film formation typically. It is process drawing for demonstrating the manufacturing process of 2nd Example. It is explanatory drawing which shows typically the mode of thin film formation in the manufacturing process of 2nd Example. It is explanatory drawing which shows typically the cross section of the fuel battery cell which has the other oxygen electrode side membrane layer 125. FIG. FIG. 5 is a process diagram showing a manufacturing process of the electrolyte membrane 100. It is explanatory drawing which shows the mode of the preparation of through-hole formation performed at a manufacturing process. It is explanatory drawing which shows the mode of through-hole formation in the oxygen electrode side membrane layer. It is explanatory drawing for demonstrating the other form of the through-hole 126. FIG. It is explanatory drawing for demonstrating the Example which used the through-hole 126 for oxygen injection in the state of the fuel cell 10 which incorporated the electrolyte membrane 100 and was completed. It is a flowchart which shows the content of oxygen escape suppression mode driving | operation. It is explanatory drawing explaining the mode of the onboard power generation of the fuel cell 10 for oxygen depletion suppression during fuel cell operation. It is explanatory drawing which shows an example of the mode of the forced electric power generation performed for oxygen injection. It is explanatory drawing which shows the other example of the mode of forced electric power generation. It is explanatory drawing explaining the modification of the voltage application for oxygen implantation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 20 ... Oxygen electrode 22 ... Oxygen flow path 30 ... Hydrogen electrode 32 ... Hydrogen flow path 40 ... Pump 50 ... Reformer 60 ... Control device 62 ... Temperature sensor 64 ... Current sensor 70 ... Power supply 80 ... Switch 100 ... Electrolyte membrane 110 ... Electrolyte membrane layer 120 ... Hydrogen separation membrane layer

Claims (9)

A fuel cell comprising a hydrogen electrode that is supplied with a hydrogen-containing fuel gas, an oxygen electrode that is supplied with an oxygen-containing oxygen gas, and an electrolyte membrane that is disposed between the electrodes and joined to both electrodes,
The electrolyte membrane is
A hydrogen separation membrane layer having a property of selectively permeating hydrogen on the hydrogen electrode side;
An electrolyte membrane layer formed on the surface of the hydrogen separation layer with an oxygen-deficient proton conductor compound exhibiting proton conduction properties in a state where oxygen atoms are introduced into interstitial oxygen defects,
An oxygen electrode side membrane layer that is formed on the surface of the electrolyte membrane layer so as to be located on the oxygen electrode side using a material exhibiting proton conduction properties and that exhibits the property of suppressing the movement of oxygen atoms in the membrane layer. Fuel cell. The fuel cell according to claim 1, wherein
The oxygen electrode side membrane layer is
A membrane layer formed on the surface of the electrolyte membrane layer with an oxygen-deficient proton conductor compound that exhibits proton-conducting properties in a state where oxygen atoms are introduced into interstitial oxygen defects,
The oxygen-deficient proton conductor compound forming the oxygen electrode side membrane layer is a compound having a lower oxygen ion conductivity than the oxygen-deficient proton conductor compound forming the electrolyte membrane layer. The fuel cell according to claim 1 or 2, wherein
The oxygen electrode side membrane layer is
A fuel cell comprising a through hole penetrating the layer, wherein the electrolyte membrane layer is exposed to the oxygen electrode in a hole range of the through hole. The fuel cell according to claim 3, wherein
Estimating means for estimating the degree of escape of oxygen atoms introduced into the interstitial oxygen vacancies in the electrolyte membrane layer;
When it is estimated that the degree of escape of the introduced oxygen atoms is increased, oxygen is replenished to the electrolyte membrane layer from the oxygen electrode side through the through holes, and the escape of oxygen atoms introduced into the interstitial oxygen vacancies is performed. A fuel cell comprising oxygen supplementing means for supplementing the fuel cell. A manufacturing method for manufacturing an electrolyte membrane disposed between a hydrogen electrode and an oxygen electrode of a fuel cell and bonded to both electrodes,
Forming a hydrogen separation membrane layer having a property of selectively permeating hydrogen (1);
(2) forming an electrolyte membrane layer on the surface of the hydrogen separation layer using an oxygen-deficient proton conductor compound that exhibits proton conduction properties in a state where oxygen atoms are introduced into interstitial oxygen defects; ,
A step (3) of forming a coating film layer on the surface of the electrolyte membrane layer using a compound having a property of proton conduction and a property of limited movement of oxygen atoms,
The step (3) of forming the coating film layer includes:
An electrolyte membrane manufacturing method that is executed in a state where the electrolyte membrane layer is in a state where oxygen atoms are introduced into the interstitial oxygen deficiency. A method for producing an electrolyte membrane according to claim 5,
The step (3) of forming the coating film layer includes:
The compound used for forming the coating film layer is an oxygen-deficient proton conductor compound that exhibits proton conduction properties in a state where oxygen atoms are introduced into interstitial oxygen defects, and forms the electrolyte membrane layer An electrolyte membrane manufacturing method using an oxygen deficient proton conductor compound having a lower oxygen ion conductivity than an oxygen deficient proton conductor compound. A method for producing an electrolyte membrane according to claim 5 or 6,
The step (2) of forming the electrolyte membrane layer includes:
The hydrogen separation layer is disposed in a chamber, and an electrolyte membrane layer is formed on the surface of the hydrogen separation layer using the oxygen deficient proton conductor compound.
The step (3) of forming the coating film layer includes:
By placing the inside of the chamber used in the step (2) of forming the electrolyte membrane layer in an environment having a high oxygen partial pressure, the electrolyte membrane layer is in a state where oxygen atoms are introduced into the interstitial oxygen defects. A method for producing an electrolyte membrane, wherein the coating membrane layer is deposited on the surface of the electrolyte membrane layer using the compound under the circumstances. A method for producing an electrolyte membrane according to claim 5 or 6,
The step (3) of forming the coating film layer includes:
By injecting oxygen atoms into the electrolyte membrane layer from the surface of the membrane, the electrolyte membrane layer is placed in a state where oxygen atoms are introduced into the defects of interstitial oxygen, and the electrolyte membrane is used with the compound. A method for producing an electrolyte membrane, comprising forming the coating film layer on a surface of the layer. A method for producing an electrolyte membrane according to claim 8,
The step (3) of forming the coating film layer includes:
Forming the coating film layer on the surface of the electrolyte membrane layer using the compound such that a partial region of the surface of the electrolyte membrane layer is exposed;
By injecting oxygen atoms from the film surface of the exposed region of the electrolyte membrane layer, the electrolyte membrane layer is placed in a state where oxygen atoms are introduced into the interstitial oxygen defects, and the exposed region is A method for producing an electrolyte membrane.

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