JP2005298849A - Oxygen pumps - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the current flowing to circuits even if a plurality of pieces of oxygen ion conductive substrates are used. <P>SOLUTION: Units parallel connected to electrode films 1 formed at the oxygen ion conductive substrates 2 are created. The units 7 are connected in series. As a result, the amount of the flowing current can be suppressed while the capability equal to that of the conventional parallel connection is retained. Accordingly, the calorific value of the circuits can be reduced and the loss of energy suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an oxygen pump that exhausts oxygen from one space or enriches oxygen into one space by electrochemically moving oxygen ions.

  Conventionally, this type of oxygen pump, when using a plurality of oxygen ion conductive substrates at the same time, electrically connects the electrode films on the same electrode side with lead wires or the like, and applies a power supply voltage in parallel. (For example, see Patent Document 1).

FIG. 1 is a plan view of a conventional oxygen pump equivalent to the contents described in Patent Document 1. As shown in FIG. As shown in FIG. 1, 16 oxygen ion conductive substrates 2 on which an electrode film 1 is formed (in Patent Document 1, 25 oxygen ion conductive substrates are illustrated) are fixed to a support member 3. Has been. Lead wires 4 are drawn from the peripheral portions of the respective electrode films 1 and gathered, and are connected to the wiring 5 in the same potential state. A lead wire 4 is drawn out from the wiring 5 and connected to one pole of the power source. A lead wire 4 is also drawn from the back surface (not shown) with the same configuration and connected to the other pole of the power source. That is, the 16 oxygen ion conductive substrates are electrically connected in parallel.
WO96 / 28589 pamphlet

  However, in the conventional configuration, since a plurality of oxygen ion conductive substrates are connected in parallel, a high current that is several times the current flowing in each lead wire flows through the lead wire in which each lead wire is gathered. It will be. Therefore, power circuits such as lead wires, lead wire connecting portions, and switch portions generate heat, causing energy loss. Furthermore, for the purpose of actual use at home, for example, a current of several tens of amperes than a voltage of several tens of volts has a problem that the configuration of the power supply circuit becomes complicated and the cost becomes high.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a low current type oxygen pump.

  In order to solve the above-described conventional problems, the oxygen pump of the present invention creates a unit in which a plurality of oxygen ion conductive substrates having electrode films formed on both front and back surfaces are connected in parallel, and the units are connected in series. It is a thing.

  As a result, the magnitude of the current flowing through the power supply circuit can be reduced without reducing the amount of oxygen that moves from one side of the oxygen ion conductive substrates arranged in a plane to the other side.

  According to the oxygen pump of the configuration of the present invention, heat generation of a circuit configured to move oxygen can be suppressed, and thus energy loss can be reduced.

  The first invention supports a plurality of oxygen ion conductive substrates having electrode films formed on both front and back surfaces, a plurality of units in which the oxygen ion conductive substrates are electrically connected in parallel, and the units. A support member, and the units are electrically connected in series. As a result, the magnitude of the current flowing through the power supply circuit connected to the oxygen pump can be reduced, heat generation can be suppressed, and energy loss can be reduced.

  In the second invention, in particular, a part of the support member of the oxygen pump of the first invention is a conductive part having conductivity, and is electrically connected to the unit. As a result, not only the operation and effect of the first invention can be obtained, but also the substitution of the lead wire in the conductive portion can eliminate the hole through which the lead wire passes, and the backflow of the generated oxygen can be prevented. it can. Further, since the area of the conductive portion can be made larger than the cross-sectional area of the lead wire, heat generation in the circuit in the oxygen pump can be reduced. Therefore, energy loss can be suppressed.

  In the third invention, in particular, the connection method between the electrode films of the first invention is lead wire connection, and the lead wire is drawn from the vicinity of the center of the electrode film. Heat is also conducted from the lead wire to the outside, and the temperature at the joining portion tends to decrease. Since the bonding site is near the center, the heat distribution on the electrode film changes radially from the center with good symmetry, so that the thermal stress can be kept small. Therefore, thermal strain on the oxygen ion conductive substrate can be alleviated, and breakage of the oxygen ion conductive substrate such as cracks and cracks and increase in interface resistance can be suppressed. With the above configuration, the magnitude of the current flowing in the circuit can be reduced, and the heat generation in the circuit energization unit can be suppressed.

  In the fourth invention, in particular, the parallel connection method of the first invention is based on the conductive member connected to at least one peripheral edge of the electrode film formed on both the front and back surfaces. Thereby, a plurality of electrode films can be connected in parallel at a time, which is convenient. Moreover, since it can be made larger than the cross-sectional area of the lead wire, heat generation in the circuit in the oxygen pump can be reduced. Therefore, useless energy loss can be suppressed.

  In the fifth invention, in particular, the thickness of the conductive member of the fourth invention is 5 to 50 μm, and the material is at least one of a single metal and an alloy. With this thickness, when a thermal stress is generated in a direction parallel to the surface of the conductive member, the stress can be absorbed by the strain and a practical physical strength can be secured. In addition, by using a single metal or alloy, the resistance of the energizing portion can be reduced, and heat generation can be reduced.

  In the sixth invention, in particular, the material of the oxygen ion conductive substrate of the first invention is lanthanum gallate. Lanthanum gallate is a perovskite metal oxide mainly composed of lanthanum and gallium, and has high oxygen ion conductivity. Therefore, a predetermined performance can be ensured even if the operating temperature of the oxygen pump is set low. That is, since the operating temperature can be set low, power consumption can be kept small. Thus, energy loss can be suppressed.

  In the seventh invention, in particular, the main component of the metal paste for parallel connection of the first to fourth inventions is the same metal as the main component of the electrode film. By using the same metal as the main component, it is possible to reduce the interfacial resistance generated between different kinds of metals and to suppress heat generation. With the above configuration, energy loss can be reduced.

  In the eighth invention, in particular, the metal of the sixth invention is at least one of gold, silver, platinum, and palladium. These metal fired bodies not only have high conductivity, but are stable in a high-temperature atmosphere, so that an increase in resistance due to oxidation can be suppressed. Therefore, the heat generated by the resistance can be reduced and energy loss can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In this embodiment, a set of units is constituted by four oxygen ion conductive substrates, and an oxygen pump is constituted by the four sets of units. However, the present invention is limited to these numbers. is not.

(Embodiment 1)
FIG. 2 is a plan view of the oxygen pump according to the first embodiment of the present invention. In FIG. 2, the electrode film 1 is formed on both the front and back surfaces of the oxygen ion conductive substrate 2 so as to leave 2 mm of the peripheral edge of the oxygen ion conductive substrate 2.

  For the electrode film 1, a noble metal such as platinum, silver, or gold, or a metal oxide such as samarium-strontium-cobalt (SSCO) is used. These electrode films 1 are formed by screen printing, electrodeposition, vapor deposition, or sputtering, but screen printing is excellent in terms of cost. The electrode film in the present embodiment is a gold thin film formed to have a thickness of 5 to 15 μm by screen printing.

  A metal oxide such as zirconia or ceria is used for the oxygen ion conductive substrate 2, and lanthanum gallate is particularly preferable. Among them, a perovskite oxide having a composition of lanthanum-strontium-gallium-magnesium (LSGMO) is most useful because of its high transport number. In this embodiment, LSGMO having a diameter of 30 mm and a thickness of 0.2 mm is used.

  The oxygen ion conductive substrate 2 is supported by the unit support member 6 so that the periphery is sandwiched. The unit support member 6 is preferably made of an insulating material such as a ceramic such as silica or alumina, or a silicate mineral such as mica, because it is used at a high temperature of 500 ° C. or higher. In the present embodiment, a general-purpose silica-alumina plate having four holes substantially equal to the electrode shape is used.

  The unit 7 is configured using the above basic members. The oxygen ion conductive substrate 2 is sandwiched and fixed by a unit support member 6 using a spacer (not shown) or the like. Each electrode film is connected in parallel by a gold lead wire 4 having a diameter of 0.3 mm. Here, as the metal paste for bonding the lead wire and the electrode film, a gold paste whose main component is the same metal as the electrode film is used.

  As described above, two equipotential wirings 5 can be formed on the back and front, and two lead wires are drawn from the wiring 5 to another unit or power supply circuit. Four sets of units 7 are connected in series. Therefore, the lead wire 4 drawn out from the wiring 5 is joined to another wiring 5 on the opposite side to the support member 8. In this case, a hole is required for the lead wire 4 to pass through. However, in this embodiment, the hole is not provided, and the lead wire 4 is connected to the conductive portion 8 penetrating the support member 3.

  A nickel wire or the like can be used as the material of the lead wire 4, but gold, silver, or platinum is preferable from the viewpoint that the main components of the electrode film and the metal paste for bonding are the same. In the present embodiment, a gold wire having a diameter of 0.3 mm is used.

  The operation and action of the oxygen pump configured as described above will be described. First, four sets of units 7 covered with a heat insulating material (not shown) are heated to 650 ° C. or more by a heater (not shown) embedded in the heat insulating material. Thereafter, when a voltage is applied to the lead wire 4 connecting the units 7 in series, oxygen on one side of the support member 3 is ionized at the electrode film 1. The oxygen ions move in the oxygen ion conductive substrate 2 by the electric field and reach the electrode film 1 on the opposite side. After that, electrons are emitted and become oxygen molecules again. At this time, since the lead wires 4 drawn out from the wiring 5 are alternately connected to adjacent units via the conductive portions 8, the side where oxygen molecules are taken in and the side where oxygen molecules are generated are separated by the support member 3. Therefore, it has the same capability as that of the conventional parallel connection. On the other hand, the magnitude of the current flowing through the power supply circuit is a quarter of that of the conventional example as shown in Table 1, and decreases in inverse proportion as the number of unit sets increases.

  In this embodiment, a voltage of 6.4 V was applied, and about 90 cc of oxygen could be obtained with a current supply of 6.0 A. In order to obtain the same amount of oxygen by the conventional example, 24.0 A was required, and the resistance of the power supply circuit portion increased to nearly 100 ° C.

  As described above, according to the present embodiment, it is possible to suppress the heat generation of the power supply circuit unit and reduce the energy loss without reducing the oxygen generation amount.

(Embodiment 2)
FIG. 3A is a plan view of a unit portion of the oxygen pump according to the second embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along the line AA of FIG.

  The difference from the first embodiment is that a lead wire connecting portion 9 that is a contact point between the electrode film 1 and the lead wire 4 is drawn out from the vicinity of the center of the electrode film. The oxygen ion conductive substrate 2 is different in that it is square, but it may be circular or polygonal.

  The operation and action of the oxygen pump are the same as in the first embodiment. However, since the lead wire connecting portion 9 is near the center of the electrode film 1, the heat distribution on the electrode film changes radially from the center with good symmetry, so that the thermal stress can be kept small. Therefore, the thermal strain on the oxygen ion conductive substrate can be relaxed, the breakage of the oxygen ion conductive substrate such as cracks and cracks can be suppressed, and the adhesion with the lead connection portion 9 can be maintained. When the adhesiveness is lowered, the contact resistance is increased, causing unnecessary heat generation.

  As described above, according to the present embodiment, it is possible to suppress the heat generation that does not directly affect the heat generation of the power supply circuit unit and the oxygen ion conductive characteristics of the oxygen pump without reducing the oxygen generation amount, and the energy loss can be suppressed.

(Embodiment 3)
FIG. 4A is a plan view of a unit portion of an oxygen pump according to the third embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along the line AA in FIG. . The units of FIG. 4 are connected in parallel. FIG. 5 is a plan view of an oxygen pump in which four units of FIG. 4 are connected in series.

The difference from the first embodiment is that by using the unit support member 6 having conductivity, the lead wire used for the connection between the electrode films is eliminated, and the process is simplified.
The material of the conductive unit support member 6 is a single metal such as nickel, titanium, gold, platinum, or the like, which is an iron chrome alloy. However, the iron chrome alloy is inexpensive and easy to process. preferable.

  Moreover, the thickness of the electroconductive unit support member 6 is 5-50 micrometers. The thickness within this range can absorb the stress due to strain when thermal stress is generated, and at the same time, can ensure practical physical strength. In addition, the resistance of the energization unit can be reduced and heat generation can be reduced. In this embodiment, an iron-chromium alloy having a thickness of 10 μm is used.

  Such units are connected in series as shown in FIG. The lead wires 4 connecting the units do not need to be connected to the conductive portion 8 and are connected in series on one surface.

  The operation and action of the oxygen pump configured as described above are the same as those in the first embodiment. However, the manufacturing process of the oxygen pump is simplified in that each electrode is connected by the conductive unit support member 6 and each unit is connected by the lead wire 4 on one surface side. Further, since the unit support member 6 having a large area is used, the resistance is small and heat generation can be suppressed.

  As described above, according to this embodiment, it is possible to suppress heat generation that does not directly affect the heat generation of the power supply circuit unit and the oxygen ion conductive characteristics of the oxygen pump without reducing the oxygen generation amount, and energy loss can be suppressed.

  As described above, the oxygen pump according to the present invention can reduce the circuit current, and thus can be used as a household electric appliance. Examples of such an electric appliance include an oxygen enricher and an oxygen aspirator, or a product in which they are incorporated as a part of a function.

Plan view of oxygen pump in conventional example The top view of the oxygen pump in Embodiment 1 of this invention (A) is a top view of the structural unit of the oxygen pump in Embodiment 2 of this invention (b) is AA sectional drawing in (a). (A) is a top view of the structural unit of the oxygen pump in Embodiment 3 of this invention (b) is AA sectional drawing in (a). Plan view of an oxygen pump according to Embodiment 3 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode film 2 Oxygen ion conductive substrate 3 Support member 4 Lead wire 6 Unit support member 7 Unit 8 Conductive part

Claims (8)

A plurality of oxygen ion conductive substrates having electrode films formed on both front and back surfaces, a plurality of units in which the oxygen ion conductive substrates are electrically connected in parallel, and a support member that supports the units; An oxygen pump, wherein the units are electrically connected in series. The oxygen pump according to claim 1, wherein a part of the support member is a conductive part having conductivity and is electrically connected to the unit. The oxygen pump according to claim 1, wherein the oxygen pumps are connected in parallel by a lead wire drawn out from the vicinity of the center of the electrode film. 2. The oxygen pump according to claim 1, wherein the oxygen pumps are connected in parallel by a conductive unit support member connected to at least one peripheral edge of the electrode films formed on the front and back surfaces. The oxygen pump according to claim 4, wherein the unit support member has a thickness of 5 to 50 μm and is made of at least one of a single metal and an alloy. The oxygen pump according to claim 1, wherein the material of the oxygen ion conductive substrate is lanthanum gallate. The oxygen pump according to any one of claims 1 to 4, wherein the main component of the metal paste for parallel connection is the same metal as the main component of the electrode film. The oxygen pump according to claim 7, wherein the metal is at least one of gold, silver, platinum, and palladium.

Images