JP2004132876A - Oxygen pump element and oxygen pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen pump element effectively using a whole electrode face by reducing electric resistance of the electrode face, suppressing drop of impressed voltage, and enhancing electrode reaction with oxygen molecules, and to provide an oxygen pump device efficiently transferring heat from a heating means to the oxygen pump element and reducing necessary electric power for heating. <P>SOLUTION: A first electrode film 22 composed of metallic oxide particles 24 having a dissociative adsorption action of oxygen molecules and metallic particles 25 with higher conductivity than the metallic oxide particles 24, and a second electrode film 23 with higher conductivity than the first electrode film 23 are provided on both faces of an oxygen ion conductive substrate 21. By this, voltage drop is suppressed in planar directions of the first electrode film 22 and the second electrode film 23, and whole faces of the electrode films can be used as electrodes. Since the electrode reaction with oxygen molecules can be activated in the first electrode film 22, oxygen ion conductivity of the oxygen pump element can be improved. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an improvement in an electrode film of an oxygen pump element using an oxygen ion conductor and an oxygen pump device equipped with the oxygen pump element.
[0002]
[Prior art]
FIG. 7 shows a conventional oxygen pump device of this type. In FIG. 7, reference numeral 1 denotes a housing, 2 denotes an oxygen pump element including a first electrode 4, a thin film 5 of an oxygen ion conductor, and a second electrode 6 formed on a porous substrate 3 such as alumina. The first electrode film 4 has a structure in which fine particles of platinum are formed on the porous substrate 3, and the second electrode 6 has a structure in which fine particles of platinum are formed on the thin film 5 of the oxygen ion conductor. Reference numeral 7 denotes a heating unit including a heater printing film 9 formed by patterning a conductive paste on an insulating substrate 8 such as an alumina substrate by screen printing. The heating unit 7 is included in the housing 1. It is placed in a state where it is open to the atmosphere.
[0003]
In this configuration, when the oxygen pump element 2 is heated to a temperature at which the oxygen pump element 2 operates as an oxygen pump by the heating means 7 and a DC voltage is applied between the first electrode 4 as a cathode and the second electrode 5 as an anode. The oxygen in the air dissociated and adsorbed on the first electrode 4 moves through the oxygen ion conductor thin film 5 as oxygen ions, is carried to the second electrode 6, and is released into the atmosphere as oxygen molecules. You. Thereby, the oxygen concentration in the container attached to the housing 1 can be reduced (for example, see Patent Document 1).
[0004]
FIG. 8 shows a conventional oxygen pump element. FIG. 8A is a plan view of the oxygen pump element, and FIG. 8B is a cross-sectional view of the oxygen pump element taken along line AA ′ in FIG. In the figure, reference numeral 10 denotes a solid electrolyte layer which is an oxygen ion conductor, 11 denotes an electrode, and an electrode 11 discloses an oxygen pump element having a structure in which one layer is formed on both surfaces of the solid electrolyte layer 10. The electrode 11 is formed by applying a paste in which particles such as platinum are mixed by using a method such as screen printing, drying and firing.
[0005]
This oxygen pump element operates similarly to the oxygen pump device of Patent Document 1 (for example, see Patent Document 2).
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-23525 [Patent Document 2]
JP-A-11-94792
[Problems to be solved by the invention]
However, the electrodes composed of a film of platinum fine particles and a fired film by screen printing disclosed in Patent Documents 1 and 2 have a film thickness of about several tens of μm and activate an electrode reaction with oxygen molecules. It has a porous structure in order to increase the electrical resistance. In such an electrode, for example, when a DC voltage is applied from the outer peripheral portion of the electrode, the voltage drops at the central portion of the electrode due to electric resistance, so that the electrode reaction with oxygen molecules (dissociative adsorption and ionization of oxygen) decreases. In addition, there is a problem that the transport amount of oxygen ions is reduced. In particular, when the oxygen pump element is large, the electrode area becomes large, so that the voltage drop becomes extremely large, and the entire electrode surface cannot be functioned effectively. In addition, when the electrode film of platinum fine particles is thickened to prevent a voltage drop, the porous structure of the electrode film itself is lost, the electrode reaction with oxygen molecules is reduced, and the transport amount of oxygen ions is reduced as a whole. There was a problem.
[0008]
Further, in the configuration of the oxygen pump device of Patent Document 2, since the oxygen pump element 2 and the heating means 7 are in a state of being released to the atmosphere, the heat energy from the heating means 7 is generated not only in the oxygen pump element 2 but also in the atmosphere. It is also used for heating air, as a result, thermal efficiency deteriorates, the power consumption of the heating means 7 required to raise the temperature to the temperature for operating the oxygen pump element increases, and the aforementioned voltage drop of the electrode surface decreases. In addition to the problem, there is a problem that the oxygen pumping element has poor oxygen ion transport efficiency. In the embodiment, since the heating means 7 is disposed above the oxygen pump element 2, the heating of the oxygen pump element 2 has a disadvantage that radiant heat is almost used and convection heat of the heated air cannot be used.
[0009]
The present invention solves the above-mentioned conventional problems, and reduces the electrical resistance of the electrode surface, suppresses a drop in applied voltage, and further enhances the electrode reaction with oxygen molecules, thereby making the entire electrode surface effective. It is an object of the present invention to provide an oxygen pump device that functions as a pump device and that efficiently transmits heat from a heating unit to the oxygen pump device to reduce the power required for heating.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, an oxygen pump element of the present invention comprises an oxygen ion conductive substrate, and a metal oxide having a main component formed on both surfaces of the oxygen ion conductive substrate having a dissociative adsorption function of oxygen molecules. A first electrode film made of metal particles having higher conductivity than the metal oxide particles and a metal particle having higher conductivity than the first electrode film formed on the surface of the first electrode film; This is a configuration in which a second electrode film is provided.
[0011]
By providing the second electrode film having higher conductivity than the first electrode film, a voltage from a power source can be applied to the entire surface of the first electrode film without causing a voltage drop, and is present in the first electrode film. Since the metal particles having higher conductivity than the metal oxide particles can efficiently supply the voltage from the second electrode film to the metal oxide particles, the atomization reaction of the oxygen molecules of the metal oxide particles having the dissociative adsorption function is performed. The ionization reaction of atomized oxygen can be activated, and the oxygen ion conductivity of the acid element pump element can be improved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The first aspect of the present invention is directed to a first aspect in which a metal oxide particle whose main component has a dissociative adsorption function of oxygen molecules on both surfaces of an oxygen ion conductive substrate and a metal particle having higher conductivity than the metal oxide particle. By providing an electrode film and a second electrode film made of metal particles having higher conductivity than the first electrode film on the electrode film, a voltage from a power supply is dropped by the second electrode film over the entire surface of the first electrode film. Can be applied without any need. Oxygen molecules diffused and passed through the second electrode film activate the atomization reaction by the catalytic action of the metal oxide particles present in the first electrode film, and reduce the voltage applied from the second electrode. The metal ions present in the first electrode film are supplied to adjacent metal oxide particles having a dissociative adsorption function, so that the ionization reaction of atomized oxygen is activated and the oxygen ion conductivity of the oxygen pump element is improved. be able to. Further, since the voltage drop at the first electrode film and the second electrode film can be suppressed, the temperature distribution due to the self-heating of the first electrode film and the second electrode film can be reduced, so that the oxygen pump element can be damaged, such as cracks. Is suppressed, and excellent durability can be realized.
[0013]
According to a second aspect of the present invention, there is provided a semiconductor device comprising: a first metal oxide particle having a dissociative adsorption function of oxygen molecules on both surfaces of an oxygen ion conductive substrate; and a metal particle having higher conductivity than the metal oxide particle. An oxygen pump element provided with an electrode film and a second electrode film made of metal particles having higher conductivity than the first electrode film, and a partitioning means for partitioning the electrode films on both surfaces of the oxygen ion conductive substrate; By comprising at least one heating means for heating the oxygen pump element, and a heat insulating material having a ventilation function arranged so as to surround the oxygen pump element, the partition means, and the heating means, the oxygen pump element and the heating means can be heated to the atmosphere. The heat efficiency to the oxygen pump element by the heating means is improved because it is not directly touched, the electric power required for heating the oxygen pump element can be reduced, and energy saving can be achieved. Further, since the entire oxygen pump element can be uniformly heated, the effect of preventing damage to the oxygen pump element is further improved, and in addition to the effect of suppressing the voltage drop at the first electrode film and the second electrode film, the oxygen pump element can be heated. Excellent performance of the pump element can be maintained for a long time. In addition, since the oxygen pump element, the partitioning means, and the heating means can have a simple structure covered with a heat insulating material having a ventilation function, the size of the oxygen pump can be reduced, and mounting on the equipment can be facilitated. it can.
[0014]
The invention according to claim 3 has a structure in which a composite oxide having a perovskite structure is used as the metal oxide having a dissociative adsorption function of oxygen molecules, thereby improving the electrode reaction of oxygen molecules and improving heat resistance. Therefore, excellent oxygen ion conductivity can be realized, and the performance can be maintained for a long time.
[0015]
According to a fourth aspect of the present invention, the composite oxide having a perovskite structure is composed of at least one of lanthanum and samarium at the A site and at least one of cobalt, iron, and manganese at the B site.
[0016]
According to a fifth aspect of the present invention, a part of the A site of the complex oxide having a perovskite structure is substituted with strontium.
[0017]
According to the constitutions of claims 4 and 5, the electrode reaction of oxygen molecules can be further enhanced, so that the oxygen ion conductivity of the oxygen pump element can be improved.
[0018]
The invention according to claim 6 is configured to use at least one of platinum, gold, silver, palladium, ruthenium, rhodium, and nickel as metal particles having higher conductivity than metal oxide particles.
[0019]
According to a seventh aspect of the present invention, at least one of platinum, gold, silver, palladium, ruthenium, rhodium, and nickel is used as the metal particles having higher conductivity than the first electrode film.
[0020]
According to the configurations of claims 6 and 7, an electrode film having low electric resistance and high heat resistance can be obtained, so that excellent performance and durability of the oxygen pump can be realized.
[0021]
According to an eighth aspect of the present invention, the first electrode film is formed of a mixture of a metal oxide particle having a dissociative adsorption function of oxygen molecules, a metal particle having higher conductivity than the metal oxide particle, and a binder made of a metal oxide. It is composed of a fired film obtained by firing.
[0022]
In a ninth aspect of the present invention, the second electrode film is constituted by a fired film obtained by firing a mixture of a binder made of metal particles and a metal oxide having higher conductivity than the first electrode film.
[0023]
According to the constitution of claims 8 and 9, it is possible to form the first electrode film and the second electrode film having excellent adhesion, thereby providing an oxygen pump element having excellent heat shock resistance such as heat shock. And the performance as an oxygen pump can be maintained for a long time.
[0024]
According to a tenth aspect of the present invention, by using bismuth oxide as a binder made of a metal oxide, the diffusion resistance of oxygen molecules in the electrode film, and the oxygen atomized and ionized in the electrode film to the oxygen ion conductive substrate. , The diffusion resistance can be reduced, so that a decrease in oxygen ion conductivity can be suppressed.
[0025]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0026]
(Example 1)
FIG. 1 is a configuration diagram of an oxygen pump element according to a first embodiment of the present invention. FIG. 1A is a sectional view, and FIG. 1B is a plan view. In FIG. 1, reference numeral 21 denotes an oxygen ion conductive substrate, which uses a zirconia (YSZ) -based material doped with yttrium, a ceria-based (SDC) doped with samarium, or a lanthanum gallate-based material. Reference numeral 22 denotes a first electrode film formed on both surfaces of the oxygen ion conductive substrate 21, and reference numeral 23 denotes a second electrode film formed on the surface of the first first electrode film 22, and the first electrode film 22, the second electrode film Reference numeral 23 denotes a porous film formed by printing and firing a paste in which a binder made of a metal oxide for strengthening adhesion is mixed. Lead members 24 for applying a voltage from an oxygen pump driving power supply (not shown) to the oxygen pump element are respectively connected to the electrode films 23.
[0027]
FIG. 2 is a cross-sectional view of the first electrode film 22 of the oxygen pump element of FIG. 1 and schematically shows the state of each particle constituting the first electrode film 22. As shown in FIG. 2, the first electrode film 22 is made of metal oxide particles 25 having a dissociative adsorption function of oxygen molecules, metal particles 26 having higher conductivity than the metal oxide particles 25, and a binder 27 made of metal oxide. And these particles are in a dispersed state.
[0028]
FIG. 3 is a cross-sectional view of the second electrode film 23 of the oxygen pump element of FIG. 1, schematically showing the state of each particle constituting the second electrode film 23, and the same materials as those in FIG. Is attached. As shown in FIG. 3, the second electrode film 23 is made of a binder 27 made of a metal oxide having metal particles 26 having higher conductivity than the first electrode film 22, and these particles are in a dispersed state.
[0029]
The operation and operation of the oxygen pump element configured as described above will be described below.
[0030]
The oxygen pump element is heated by the heating means to a temperature at which it operates as an oxygen pump. Next, a voltage is applied from an oxygen pump driving power source via the lead member 24, using one of the second electrode films 23 as a cathode and the other as an anode. When the temperature of the oxygen ion conductive substrate 21 is raised to 500 to 800 ° C., the following electrode reaction is considered to occur in the first electrode film 22 on the cathode side. Oxygen molecules existing in the space on the cathode side diffuse through the porous films of the second electrode film 23 and the first electrode film 22, and the oxygen molecules mainly have a dissociative adsorption function of the oxygen molecules existing in the first electrode film 22. The metal oxide particles 24 dissociate and adsorb and are atomized. When a voltage from the driving power supply is applied to the metal particles 25 having a higher conductivity than the metal oxide particles 24 included in the first electrode film 22 through the second electrode film 23, the voltage is adsorbed on the metal oxide particles 24. The oxygen atoms and the oxygen atoms diffused into the metal particles 25 having better conductivity than the metal oxide particles 24 receive electrons and are taken into the oxygen ion conductive substrate 21 as oxygen ions. On the other hand, oxygen ions move in the oxygen ion conductive substrate 21 and reach the first electrode film 22 on the anode side. Oxygen ions that reach the first electrode film 22 become oxygen molecules due to an electrode reaction opposite to that of the cathode side, diffuse through the porous films of the first electrode film 22 and the second electrode film 23, and are released to the external space.
[0031]
Since the second electrode film 23 has higher conductivity than the first electrode film 22, a voltage from a power supply can be applied to the entire surface of the first electrode film 22 without voltage drop, and the entire surface of the first electrode film 22 can be applied. It can function effectively.
[0032]
Oxygen molecules diffused and passed through the second electrode film 23 are activated by the catalytic action of the metal oxide particles 25 present in the first electrode film, and activated by the second electrode 23. Since the applied voltage is supplied to the adjacent metal oxide particles 25 through the metal particles 26 existing in the first electrode film 22, the ionization reaction of atomized oxygen is activated, and the oxygen ion conductivity of the oxygen pump element is improved. Can be done.
[0033]
Further, since the voltage drop in the surface direction of the first electrode film 22 and the second electrode film 23 can be suppressed, the temperature distribution due to the self-heating of the first electrode film 22 and the second electrode film 23 can be reduced, so that oxygen Damage such as cracks of the pump element is suppressed, and excellent durability can be realized. In addition, since the first electrode film 22 includes the metal oxide particles 25 that enhance electrode reactivity such as atomization of oxygen molecules, the atomization reaction of oxygen molecules can be activated, so that a higher oxygen ion conductivity can be achieved. Nature can be realized.
[0034]
Next, specific effects of the present invention will be described with reference to FIGS.
[0035]
A lanthanum gallate-based solid electrolyte ((La _0.8 SrSr _0.2 ) (Ga _0.8 Mg _0.2 ) O ₃ ) having a diameter of 21 mm and a thickness of 0.3 mm was used as the oxygen ion conductive substrate 21. Perovskite-type composite oxide (Sm _0.5 Sr _0.5 CoO ₃ ) particles as metal oxide particles 25 having a dissociative adsorption function of oxygen molecules on both surfaces of the ion conductive substrate 21. Fine particles of gold (Au) as the highly conductive metal particles 26, bismuth oxide (Bi ₂ O ₃ ) particles as the binder 27 composed of an organic solvent and a metal oxide, and a cellulose-based vehicle, and a paste obtained by mixing these is screened. A printing film was formed by printing, and the first electrode film 22 having a diameter of 16 mm and a thickness of 10 to 20 μm was formed by drying and firing. At this time, the ratio of the perovskite-type composite oxide particles to the gold fine particles was 1: 1. Next, on each surface of the first electrode film 22, fine particles of gold (Au) as the metal particles 26, bismuth oxide (Bi ₂ O ₃ ) particles as the binder 27 made of an organic solvent and a metal oxide, and a cellulose-based vehicle are provided. A printed film was formed by screen printing using a paste obtained by mixing the two, dried, and fired to form a second electrode film 23 having a diameter of 16 mm and a film thickness of 10 to 20 μm. Since the second electrode film 23 does not include the metal oxide fine particles 25 of the first electrode film 22, it can be an electrode film having higher conductivity than the first electrode film 22.
[0036]
FIG. 4 is a circuit configuration diagram for measuring the VI characteristics of the oxygen pump element of the present invention. As shown in FIG. 4, a DC voltage from a power supply 28 is applied to the second electrode film 23 via the lead member 24.
[0037]
With respect to the oxygen pump element configured as described above, a DC voltage was applied by the circuit shown in FIG. 4 and the VI characteristics were evaluated. FIG. 5 is a graph showing the VI characteristics of the oxygen pump element according to the example of the present invention. For comparison, an oxygen pump element (comparative example) having only the first electrode film 22 according to the present invention is shown. The VI characteristics are also shown. As is apparent from FIG. 5, the oxygen pump element of the present invention has a larger ion current due to oxygen ions with respect to the voltage than the oxygen pump element of the comparative example.
[0038]
Examples of the highly conductive metal particles 26 used for the first electrode film 22 and the second electrode film 23 include platinum, silver, palladium, ruthenium, rhodium, and nickel in addition to gold. In addition, the same effect as that of gold can be obtained, and an electrode film having high heat resistance can be obtained, so that excellent oxygen pump performance and durability can be realized.
[0039]
The first electrode film 22 is formed by firing a mixture of a metal oxide particle 25 having an oxygen molecule dissociative adsorption function, a metal particle 26 having higher conductivity than the metal oxide particle 25, and a binder 27 made of a metal oxide. By forming the obtained fired film and the second electrode film 23 with a fired film obtained by firing a mixture of a metal particle 26 having a higher conductivity than the first electrode film 22 and a binder 27 made of a metal oxide, Since excellent adhesion can be realized, an oxygen pump element excellent in heat shock resistance such as heat shock can be provided, and performance as an oxygen pump can be maintained for a long period of time.
[0040]
Further, by using bismuth oxide as the binder 27 made of metal oxide, the diffusion resistance of oxygen molecules in the second electrode film 23 and the oxygen ion conductive substrate of the atomized and ionized oxygen in the first electrode film 22 are formed. Therefore, the diffusion resistance to oxygen can be reduced, so that a decrease in oxygen ion conductivity can be suppressed.
[0041]
In addition, as the metal oxide particles 25 having a dissociative adsorption function, a composite oxide having a perovskite structure having high heat resistance while enhancing an electrode reaction with oxygen molecules is suitable, and excellent oxygen ion conductivity can be realized. In addition, the performance can be maintained for a long time.
[0042]
In particular, among the perovskite-type composite oxides, the A site is composed of at least one of lanthanum and samarium and the B site is composed of at least one of cobalt, iron and manganese, and a part of the A site is substituted with strontium. The resulting material has excellent conductivity and electrode reactivity with oxygen.
[0043]
(Example 2)
FIG. 6 is a sectional view of the oxygen pump device according to the second embodiment of the present invention. In FIG. 6, reference numeral 29 denotes an oxygen pump element, and the oxygen pump element 29 having the configuration described in the first embodiment is used. 6, the oxygen pump element 29 is denoted by the same reference numeral as the oxygen pump element of the first embodiment, and the description is omitted.
[0044]
In FIG. 6, reference numeral 30 denotes a partitioning means for partitioning the first electrode film 22 and the second electrode film 23 formed on both surfaces of the oxygen ion conductive substrate 21, and has an opening facing the second electrode film 23. It is bonded to the oxygen ion conductive substrate 21 by a heat-resistant adhesive material such as glass. As the partitioning means 30, a metal plate or a foil of nickel, iron-chromium alloy, titanium, gold, platinum or the like, a ceramic plate of alumina, mullite or the like is used, but the thermal expansion difference with the oxygen ion conductive substrate 21 is small, Since a small thermal distortion is required, a metal foil of nickel or an iron-chromium alloy is applied. Reference numeral 31 denotes a heating unit provided below the oxygen pump element 29, and is connected via a lead wire 33 to a heating power supply 32 that applies electric power to the heating unit 31. As the heating means 31, a heating wire or foil such as an iron-chromium alloy or a nickel-chromium alloy is used.
[0045]
Numeral 34 denotes a heat insulating material having a ventilation function, which is composed of a porous body having a large number of communication holes, and is arranged so as to cover the oxygen pump element 29, the partitioning means 30, and the heating means 31. It is housed in a housing 35 provided with an opening so that oxygen can flow out to the atmosphere. As the heat insulating material 34 having the ventilation function, an aggregate of silica particles whose main component is an inorganic oxide is used.
[0046]
The operation and operation of the oxygen pump device configured as described above will be described below.
[0047]
First, when electric power is applied to the heating means 31 by the heating power supply 32, the heating means 31 heats the oxygen pump element 29. Next, a predetermined voltage is applied to each of the second electrode films 23 from the oxygen pump drive power supply 36 via the lead member 24 to the oxygen pump element 29. In the case of this embodiment, the lower second electrode film 23 is a cathode, and the upper second electrode film 23 is an anode. When the temperature of the oxygen pump element 29 is raised to 500 to 800 ° C. by the heating means 31 in this state, oxygen molecules existing in the space on the cathode side are dissociated and adsorbed on the first electrode film 22, and are converted into oxygen ions on the oxygen ion conductive substrate 21. And carried to the first electrode film 22 on the anode side. Oxygen ions that reach the first electrode film 22 on the anode side become oxygen molecules, diffuse through the first electrode film 22 and the second electrode film 23, and are released to the external space. Since the space on the cathode side and the space on the anode side are separated by the partition means 30, oxygen molecules existing in the space on the cathode side can always be transported to the space on the anode side. When oxygen molecules in the space on the cathode side are transported to the space on the anode side, the oxygen concentration on the cathode side decreases, but the air containing oxygen molecules in the atmosphere passes through the communication holes of the heat insulating material 34 on the cathode side having a ventilation function. It diffuses and flows into the space on the cathode side. On the other hand, oxygen molecules released from the second electrode film 23 from the space on the anode side diffuse through the heat insulating material 34 having a ventilation function on the anode side, and flow out into the atmosphere. While the oxygen pump element 29 is operating, oxygen molecules continue to be transported as shown by arrows in the figure. At this time, if the container is attached so as to be hermetically closed on the cathode side, the oxygen concentration in the container can be reduced.
[0048]
As described above, the heat insulating material 34 having the ventilation function is arranged so as to surround the oxygen pump element 29, the partitioning means 30 for partitioning the space, and the heating means 31 for heating the oxygen pump element 29, Since the oxygen pump element 29 and the heating means 31 do not come into direct contact with the atmosphere, the thermal efficiency is improved, the electric power required for heating the oxygen pump element 29 can be reduced, and energy can be saved. In addition, the entire oxygen pump element 29 can be uniformly heated, and the temperature distribution due to self-heating of each electrode film can be suppressed by the action of suppressing the voltage drop of the first electrode film 22 and the second electrode film 23. Therefore, the oxygen pump element 29 is prevented from being damaged due to cracks and the like, and the durability and reliability of the oxygen pump device can be improved. Further, since the oxygen pump element 29, the partitioning means 30, and the heating means 31 can have a simple structure covered with a heat insulating material 34 having a ventilation function, the size of the oxygen pump can be reduced, and the apparatus can be mounted on equipment. Can be facilitated.
[0049]
In addition, in particular, by forming the heat insulating material 34 having a ventilation function as a porous body having a large number of communication holes as in the present embodiment, it is possible to ensure a sufficient ventilation rate for air and oxygen molecules, Since the air introduced into the pump element 29 is gradually heated while passing through the communication hole of the porous body, the cooling of the oxygen pump element 29 is suppressed, and the thermal efficiency of the heating means 31 can be further increased.
[0050]
Note that the oxygen pump device of the present invention is applied to a device requiring a low oxygen atmosphere such as a food storage or a device requiring a higher oxygen concentration than the atmosphere.
[0051]
【The invention's effect】
As described above, according to the present invention, an electrode reaction with oxygen molecules can be caused on the entire surface of the electrode film of the oxygen pump element, so that the oxygen ion conductivity of the oxygen pump element can be improved. The performance as a pump can be improved, and the voltage drop on the electrode film can be suppressed, so that the temperature distribution due to the self-heating of the electrode film can be reduced, so that the damage such as cracks of the oxygen pump element is suppressed. Thus, excellent durability can be realized.
[0052]
Further, the oxygen pump device can improve the heat efficiency of the oxygen pump element by the heating means, so that the power required for heating the oxygen pump element can be reduced, and energy saving can be achieved. Since the entire element can be heated uniformly, damage such as cracks of the oxygen pump element can be prevented, and the durability and reliability of the oxygen pump device can be improved. In addition, since the oxygen pump device can have a simple structure, the size of the oxygen pump can be reduced, and mounting on the device can be facilitated.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view of an oxygen pump element according to a first embodiment of the present invention. FIG. 1B is a plan view of an oxygen pump element according to a first embodiment of the present invention. FIG. FIG. 3 is a cross-sectional view of a second electrode film of the present invention. FIG. 4 is a circuit configuration diagram for measuring VI characteristics of the oxygen pump element according to the first embodiment of the present invention. FIG. 6 is a graph showing VI characteristics of an oxygen pump element. FIG. 6 is a cross-sectional view of an oxygen pump device according to a second embodiment of the present invention. FIG. Sectional view of oxygen pump element in Patent Document 2
Reference Signs List 21 Oxygen ion conductive substrate 22 First electrode film 23 Second electrode film 25 Metal oxide particles having dissociative adsorption function of oxygen molecules 26 Highly conductive metal particles 27 Binder made of metal oxide 29 Oxygen pump element 30 Partitioning means 31 heating means 34 heat insulating material having ventilation function

Claims (10)

An oxygen ion conductive substrate, the main components formed on both surfaces of the oxygen ion conductive substrate are composed of metal oxide particles having a dissociative adsorption function of oxygen molecules and metal particles having higher conductivity than the metal oxide particles. An oxygen pump element comprising: a first electrode film; and a second electrode film formed of metal particles having higher conductivity than the first electrode film formed on the surface of the first electrode film. An oxygen ion conductive substrate, the main components formed on both surfaces of the oxygen ion conductive substrate are composed of metal oxide particles having a dissociative adsorption function of oxygen molecules and metal particles having higher conductivity than the metal oxide particles. An oxygen pump element comprising: a first electrode film to be formed; a second electrode film made of metal particles having higher conductivity than the first electrode film formed on the surface of the first electrode film; A partitioning means for partitioning the electrodes on both surfaces of the conductive substrate, at least one heating means for heating the oxygen pump element, and a ventilation function arranged so as to surround the oxygen pump element, the partitioning means and the heating means. An oxygen pump device comprising a heat insulating material. Metal oxide has a dissociation adsorption of oxygen molecules particles, chemical formula ABO oxygen pump element and the oxygen pump apparatus according to claim 1 or 2, wherein a complex oxide having a perovskite structure represented by _3. The oxygen pump element and the oxygen pump device according to claim 3, wherein the composite oxide having a perovskite structure is composed of at least one of lanthanum and samarium at the A site and at least one of cobalt, iron, and manganese at the B site. . The oxygen pump element and the oxygen pump device according to claim 3 or 4, wherein the composite oxide having a perovskite structure has a part of the A site substituted with strontium. 3. The oxygen pump element and the oxygen pump device according to claim 1, wherein the metal particles having higher conductivity than the metal oxide particles are at least one of platinum, gold, silver, palladium, ruthenium, rhodium, and nickel. The oxygen pump element and the oxygen pump device according to claim 1 or 2, wherein the metal particles having higher conductivity than the first electrode film are at least one of platinum, gold, silver, palladium, ruthenium, rhodium, and nickel. The first electrode film is a fired film obtained by firing a mixture of a metal oxide particle having a dissociative adsorption function of oxygen molecules and a binder made of a metal oxide and a metal oxide having higher conductivity than the metal oxide particle. The oxygen pump element and the oxygen pump device according to claim 1 or 2, which are configured. The oxygen pump element according to claim 1, wherein the second electrode film is formed of a fired film obtained by firing a mixture of a binder made of metal particles and a metal oxide having higher conductivity than the first electrode film. Oxygen pump device. 10. The oxygen pump element and the oxygen pump device according to claim 8, wherein the binder composed of a metal oxide is mainly composed of bismuth oxide.

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