JP2007277070A - Oxygen supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen supply device which supplies oxygen in a short period of time while reducing temperature variations to a plurality of solid electrolytes without causing cracks in solid electrolytes. <P>SOLUTION: The voltage of the first voltage application means 14 which applies voltage to an oxygen pump element having a solid electrolyte 1 is controlled by the first voltage control means 15. The voltage of the second application means 19 which applies voltage to a heating means 16 for heating the oxygen pump element is controlled by a second voltage control means 18. When starting, voltage (a) is applied for a certain period of time by the second voltage control 18, and the applied voltage is changed to the voltage (b). Consequently, during the process of the temperature decrease of once raised temperature of the solid electrolyte 1, a specific voltage is applied to the oxygen pump element by the first voltage application means 14 to start. The relationship of the voltage (a) and voltage (b) satisfies (a)>(b). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an oxygen supply apparatus equipped with an oxygen pump element using an oxygen ion conductive solid electrolyte, and more particularly to a control method thereof.

  Conventionally, this type of oxygen pump element is configured by forming electrode films 102 and 103 on both sides of an oxygen ion conductive substrate 101 as shown in FIG. Lead members 104 and 105 are taken out from specific portions of the electrode films 102 and 103, respectively, and connected to a power source (not shown). The oxygen ion conductive substrate 101 is held by a support member 1066 (see, for example, Patent Document 1).

  In addition, as shown in FIG. 10, the oxygen pump element 107 includes a first electrode 109 formed on a porous substrate 108 such as alumina, a thin film 110 of oxygen ion conductor, and a second electrode 111. The first electrode film 109 has a structure in which platinum fine particles are formed on the porous substrate 108, and the second electrode 111 is formed by forming a thin film obtained by combining the platinum fine particles with the thin film 110 of the oxygen ion conductor.

  The heating means 112 includes a heater printing film 114 formed by patterning a conductive paste on an insulating substrate 113 such as an alumina substrate by screen printing. The heating means 112 is not included in the casing 115 and is disposed in a state released to the atmosphere.

  In this configuration, when the oxygen pump element 107 is heated to a temperature at which the oxygen pump element 107 operates as an oxygen pump by the heating means 112 and a DC voltage is applied between both electrodes using the first electrode 109 as a cathode and the second electrode 111 as an anode, As shown in FIG. 2, oxygen in the air dissociated and adsorbed by the first electrode 109 moves as oxygen ions in the thin film 110 of the oxygen ion conductor, is carried to the second electrode 111, and is released into the atmosphere as oxygen molecules. Is done. Thus, the oxygen concentration in the container attached to the housing 115 can be reduced (see, for example, Patent Document 2).

  Further, other oxygen pumps include those shown in FIGS. That is, when a plurality of oxygen ion conductive substrates are used at the same time, the electrode films on the same surface side are electrically connected by lead wires or the like, and the power supply voltage is applied in parallel.

That is, 25 oxygen ion conductive substrates 116 are fixed to the support member 117. Lead wires 119 are drawn from the peripheral portions of the respective electrode films 118 and gathered, and are connected to the wiring in the same potential state. A lead wire 120 is drawn from the wiring and is connected to one pole of the power source. In addition, a lead 121 wire similarly drawn from the back surface is connected to the other pole of the power source (see, for example, Patent Document 3).
JP 2000-86204 A JP 11-23525 A WO96 / 28589 pamphlet

  However, in the oxygen pump element shown in FIG. 9, the amount of heat during operation of the oxygen pump element is concentrated on the lead members 104 and 105, and local temperature spots are generated on the oxygen ion conductive substrate 102. There was a problem that cracking occurred.

  For this reason, there has been a problem of how to disperse the large heat generated during the operation of the oxygen pump element without any unevenness and to provide a long-term guarantee for that portion. Although there is no particular description about the starting method of the element, it is generally considered that the oxygen pump element is applied after being heated to a predetermined temperature.

  Further, in the configuration of the oxygen pump device shown in FIG. 10, since the oxygen pump element 107 and the heating means 112 are released to the atmosphere, the heat energy from the heating means 112 is not only in the oxygen pump element 107 but also in the atmosphere. As a result, the thermal efficiency is deteriorated, the power consumption of the heating means 112 necessary for raising the temperature to the temperature at which the oxygen pump element 107 is operated increases, and the oxygen ions of the oxygen pump element are increased. Had the problem of poor transport efficiency. Further, since the heating means 112 is disposed on the upper part of the oxygen pump element 107, the oxygen pump element 107 has a drawback that most of the radiation heat is used, and the convection heat of the heated air cannot be used.

  In this case as well, there is no particular description about the method for starting the element, but it is generally considered that the oxygen pump element is applied after being heated to a predetermined temperature.

  11 and 12, since a plurality of oxygen ion conductive substrates 116 are connected in parallel, a large current flows through the lead wires 120 and 121 where the lead wires are gathered. .

  Therefore, there is a problem that it is necessary to use a sufficiently thick lead wire or a special lead wire having a small electric resistance. Moreover, heat may be generated even in a portion having a small resistance value such as a connection portion or a switch portion.

  Further, for example, considering actual use at home, a current of several tens of amperes is more complicated than a voltage of several tens of volts, resulting in a problem that the configuration of the power supply circuit is complicated and the cost is high. In this case as well, there is no particular description about the method for starting the element, but it is generally considered that the oxygen pump element is applied after being heated to a predetermined temperature.

  The present invention solves the above-described conventional problems, and by intentionally changing the voltage applied to the heating means, temperature unevenness for a plurality of solid electrolytes is reduced as much as possible, and an unreasonable load is generated on the solid electrolytes. An object of the present invention is to provide an oxygen supply device capable of supplying oxygen in a shorter time.

  In order to solve the conventional problems, an oxygen supply device control method according to the present invention includes an oxygen pump element having at least a solid electrolyte, first voltage applying means for applying a voltage to the oxygen pump element, A first voltage control means for controlling one voltage application means; a heating means for heating the oxygen pump element; a second voltage application means for applying a voltage to the heating means; and a second voltage control means for controlling the second voltage application means. Two voltage control means, and a heat-insulating housing for housing the oxygen pump element and the heating means, and after the voltage a is applied for a predetermined time by the second voltage control means at the start-up, By changing to b, when the temperature of the solid electrolyte once increased, the voltage is applied by applying a predetermined voltage to the oxygen pump element by the voltage applying means A. The relationship between the voltage a and the voltage b at this time is obtained by setting the voltage a> Voltage b.

As a result, the temperature is rapidly heated by the heating means at the start-up, and the applied voltage is lowered, so that the temperature unevenness occurring between the plurality of solid electrolytes due to the layout at the time of heating is converged over time. Since the voltage is applied to the pump element, the oxygen pump element can be started smoothly without causing an excessive load on the solid electrolyte.

  The oxygen supply apparatus of the present invention can reduce temperature unevenness with respect to a plurality of solid electrolytes, and can further shorten the rise time during which oxygen can be supplied without causing an excessive load on the solid electrolytes.

  According to a first aspect of the present invention, there is provided an oxygen pump element comprising at least a solid electrolyte, first voltage applying means for applying a voltage to the oxygen pump element, first voltage control means for controlling the first voltage applying means, A heating means for heating the oxygen pump element; a second voltage applying means for applying a voltage to the heating means; a second voltage control means for controlling the second voltage applying means; the oxygen pump element and the heating means; The solid-state electrolyte that is once heated, by applying the voltage a by the second voltage control means for a predetermined time at the start-up, and then changing the applied voltage to the voltage b. At the time when the temperature is falling, the oxygen pump element is activated by applying a predetermined voltage to the oxygen pump element by the voltage applying means A, and the relationship between the voltage a and the voltage b at this time is set to voltage a> voltage b. It is a thing.

  As a result, after starting up, the heating means rapidly heats up at the maximum, and then the applied voltage is lowered, so that the temperature unevenness that occurs between the multiple solid electrolytes due to the layout at the time of heating elapses in the housing having the heat insulating means. Since the voltage is applied to the oxygen pump element in this state, the oxygen pump element can be started smoothly without causing an excessive load on the solid electrolyte. As a result, the risk of generating cracks in the solid electrolyte is greatly reduced.

  According to a second aspect of the present invention, there is provided an oxygen pump element comprising at least a solid electrolyte, first voltage application means for applying a voltage to the oxygen pump element, first voltage control means for controlling the first voltage application means, Heating means for heating the oxygen pump element; second voltage applying means for applying a voltage to the heating means; second voltage control means for controlling the second voltage applying means; the oxygen pump element and the heating means; In the oxygen supply device including the housing having heat insulation to be housed, the voltage a is applied by the second voltage control unit for a predetermined time at the start-up, and then the voltage is temporarily stopped to stop the temperature application. During a transition in which the temperature of the solid electrolyte is lowered, the oxygen pump element is activated by applying a predetermined voltage c to the oxygen pump element by the first voltage applying means, and then operating at a predetermined current value. The voltage applied by the first voltage applying means is finally shifted to the voltage d so as to be maintained, and the relation between the voltage c and the voltage d at this time is set to voltage c <voltage d It is.

  As a result, after starting up, the heating means is stopped at the maximum speed after starting up, and then the heating means is stopped, and the temperature unevenness generated between the plurality of solid electrolytes due to the layout at the time of heating converges with the passage of time inside the housing having the heat insulating means. In this state, since the voltage is applied to the oxygen pump element, an excessive load is not generated on the solid electrolyte, and the oxygen pump element can be started smoothly.

  Further, by shifting the voltage c applied to the oxygen pump element to a larger voltage d, the oxygen supply that reduces the power consumption required when supplying oxygen by efficiently balancing the heat by the amount of heat generated by the oxygen pump element. Equipment can be provided.

In particular, the third invention provides a plurality of openings in the metal foil member for the oxygen pump element of the first or second invention, and the openings are provided with an oxygen ion conductive solid through an insulating film. A plurality of electrolytes are arranged in a gas-sealed structure, the metal foil member serves as a space partition means, a positive electrode film and a negative electrode film are formed on both surfaces of the solid electrolyte, and the plurality of solid electrolytes are the positive electrode film and Since the negative electrode film is configured to be electrically connected in series, the voltage applied to a large number of solid electrolytes can be accumulated. It becomes possible to operate with.

  In addition, since the solid electrolyte is disposed on a thin metal foil member, it has sufficient gas sealing properties and sufficient flexibility against thermal shock and thermal strain, and suppresses peeling even in the long term. Can do.

  In the fourth invention, in particular, with respect to the solid electrolyte of any one of the first to third inventions, one solid electrolyte is divided into a plurality of positive electrode films and negative electrode films to constitute a capacitor. The positive electrode film and the negative electrode film are arranged in such a pair structure, and the voltage applied to one solid electrolyte is applied to the positive electrode film and the negative electrode film. By dividing it, it becomes possible to further accumulate, and with a small number of solid electrolytes, the current value to the whole oxygen pump element can be kept low, and a high voltage and a small current can be realized to operate with a general-purpose power source.

  The fifth aspect of the invention is a blower circuit having a supply / exhaust mechanism equipped with a heat exchanger on the negative electrode side of the oxygen pump element, particularly with respect to the oxygen supply device of any one of the first to fourth aspects of the invention. By being arranged, new air is forcibly supplied to the negative electrode side of the oxygen pump element, so even if the oxygen supply device has a large capacity, oxygen gas is supplied to the negative electrode side of the solid electrolyte, It becomes possible to demonstrate sufficient ability. In addition, since the air blower circuit is equipped with a heat exchanger, heat loss due to exhaust can be kept small.

  In the sixth aspect of the invention, in particular, by using a ribbon heater for the heating means of any one of the first to fifth aspects, a temperature at which the solid electrolyte can conduct oxygen ions, for example, 400 to 600 ° C. Heating can be rapidly performed with the maximum electric power, and the electric power can be easily changed after that.

  In the seventh invention, in particular, the ribbon heater according to the sixth invention has a surface area covered with an inorganic porous film to increase a geometric surface area that generates heat. It can be suitable for rapid heating.

  In the eighth invention, in particular, the inorganic porous film of the seventh invention is composed mainly of ZrO2, TiO2, Al2O3, and SiO2, so that the thermal expansion of the ribbon heater made of a metal material can be prevented. An inorganic porous film having rigidity that does not peel off can be formed.

  In particular, the ninth invention is the first electrode film directly bonded to the solid electrolyte with respect to the positive electrode film and the negative electrode film of any one of the third to eighth inventions, and the first electrode film on the first electrode film A first electrode film comprising a composite metal oxide component as a main electrode on a solid electrolyte, and a second electrode film as a film mainly comprising a noble metal component. Since the second electrode film is made of a highly conductive material, the same potential can be applied to the electrode portion having a certain area. Also, the first electrode film can enhance the electrode reaction for dissociating and adsorbing oxygen as an intermediate layer between the solid electrolyte and the second electrode film, so that a good catalytic action for changing from oxygen molecules to oxygen ions can be obtained. .

The tenth invention is a perovskite-type composite metal oxide mainly composed of lanthanum and gallium by using the solid electrolyte of any one of the first to ninth inventions as lanthanum gallate, It has oxygen ion conductivity at 400 ° C or higher. Therefore, since sufficient capability can be obtained by maintaining the operating temperature of the oxygen pump element at a relatively low temperature of about 600 ° C., deterioration of the oxygen pump element can be suppressed even in the long term.

  In an eleventh aspect of the invention, in particular, by using a ferritic stainless steel containing aluminum as the metal foil member of any one of the third to tenth aspects of the invention, it has excellent characteristics against high-temperature oxidation. Thus, stable characteristics can be maintained even when used at a temperature near 800 ° C. for a long time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
In FIG. 1, a solid electrolyte 1 is a sintered body of substitutional type lanthanum gallate (La _0.8 Sr _0.2 Ga _0.8 Mg _0.2 O ₃ ) molded into a flat plate having an arbitrary thickness. As the electrode film, the positive electrode film 2 and the negative electrode film 3 are formed so as to exhibit oxygen ion conductivity. Here, the solid electrolyte 1 will be described assuming a size of 16 × 16 mm and a thickness of 100 μm.

For the positive electrode film 2 and the negative electrode film 3, a perovskite complex oxide having conductivity was used. Specifically, a paste prepared by mixing Sm _0.5 Sr _0.5 CoO ₃ with a cellulose-based vehicle as an organic solvent is formed by screen printing to form a printed film, dried, and fired at 1100 ° C. to obtain a film thickness of about 15 μm. An electrode film having porosity was formed.

  Further, an Au porous positive second electrode film 4 and a negative second electrode film 5 were laminated on the surfaces of the positive electrode film 2 and the negative electrode film 3 as a second electrode film. In this case, a printed film was formed by screen printing using Au paste, dried, and baked at 800 ° C. to form a second electrode film having a thickness of about 3 μm. The positive second electrode film 4 and the negative second electrode film 5 can improve surface distribution unevenness on the solid electrolyte with respect to the potential when a voltage is applied between the positive electrode film 2 and the negative electrode film 3.

  FIG. 2 is a schematic configuration diagram of the oxygen pump element. Here, an oxygen pump element using 36 solid electrolytes 1 will be described. Each solid electrolyte 1 is connected to one metal foil member 6 on the negative electrode film 3 side. Fe-20Cr-5Al, 12 μm is used as the metal foil member 6, and 36 openings 713 × 13 mm are provided so that the surface of the negative second electrode film 5 of the solid electrolyte 1 is exposed.

  An insulating film 7 is disposed around the opening that has a bonding relationship with the solid electrolyte 1. Specifically, a BaO—CaO—Al 2 O 3 —SiO 2 glass ceramic paste was formed by screen printing to form a printed film, dried, and then fired at 880 ° C. to form an insulating film 8 having a thickness of about 10 μm. . The dimensions are an outer dimension of 18 × 18 mm and an inner dimension of 13 × 13 mm so that a part of the lead extraction portion can be formed.

  Further, a conductive film 8 is disposed on the insulating film 7 while maintaining an insulating relationship with the metal foil member 6. Specifically, a printed film was formed by screen printing using Au paste, dried, and baked at 800 ° C. to form a conductive film 8 having a thickness of about 3 μm.

  Solid electrolyte 1 and its outer peripheral negative electrode side are joined to conductive film 8 by a conductive film (not shown). Since the size of the solid electrolyte 1 is 16 × 16 mm and the opening provided in the metal foil member 6 is 13 × 13 mm, the joint portion formed by the conductive film has a width of 1.5 mm around the solid electrolyte 1.

  Screen printing was performed twice using Au paste as the conductive film. Then, 36 solid electrolytes 1 were bonded and fixed to the metal foil member 6 by drying and firing at 780 ° C. while applying a predetermined load.

  The lead extraction portion formed by the conductive film 8 electrically connected to the negative second electrode film 5 of the adjacent solid electrolyte 1 and the adjacent solid electrolyte positive second electrode film 4 side are connected to each other to electrically connect the series circuit. It has become. The connection was made with a gold wire 9 of φ0.1 mm. The individual solid electrolytes 1 are numbered in the order connected to the series circuit. The lead part 10 finally connected to the positive second electrode film of the first solid electrolyte 1 and the negative second electrode film of the 36th solid electrolyte 1 are electrically connected to the 36 solid electrolytes 1. A voltage is applied to the entire oxygen pump element from the lead portion 11 connected to the conductive film.

FIG. 3 shows an oxygen supply apparatus using the oxygen pump element.
Around one metal foil member 6 serving as a space partitioning means for 36 solid electrolytes 1, it is fixed to a support 13 via an electrically insulating gas sealant 12.

  The lead part 10 and the lead part 11 are connected to a first voltage applying means 14 via a conducting wire, and the first voltage applying means 14 is connected to a first voltage control means 15. The heating means 16 composed of a ribbon heater or the like is arranged to face the surface on the negative electrode side so that heat is evenly transmitted to the plurality of solid electrolytes 1.

  A second voltage applying means 19 is connected to the heating means 16 with a second voltage control means 18 having a means 17 for detecting the temperature of the solid electrolyte 1.

  FIG. 4 shows the heating means 16. That is, Fe-20Cr-5Al having a width of 1 mm and a thickness of 0.1 mm is used as the heater wire 20, and a mica frame 21 is used to fix the heater wire 20.

  The outer dimension of the heating means 16 is 130 × 63 mm, and two of these are arranged below the oxygen pump element. The two ribbon heaters are electrically constituted by a parallel circuit, and a voltage is applied to the lead portions 22 and 23.

  On the surface of the heating means 16, an inorganic porous film 24 is formed only in a straight portion with respect to the mica frame 21. The inorganic porous film 24 was formed by an aqueous solution in which ZrO2 particles and TiO2 particles were mixed and diffused in the SiO2 sol. After spraying the aqueous solution, the heater was energized to form an inorganic porous film 24 of about 20 μm.

  The heat insulating means 25 and 26 suppress the loss of heat generated by the heating means 16. Here, a heat insulating member molded into a flat plate mainly composed of silica and alumina was used. The heat insulating means 25 is provided with a vent hole 27 for supplying air.

  The air holes 27 are designed so that a space is provided in a wide area of the heat insulating member and is uniformly supplied to the negative electrode side of the solid electrolyte 1 by diffusion resistance accompanying air flow.

  The outside air from the blower pump 28 is guided to the vent hole 27 through the supply passage 31 of the blower circuit 30 provided with the heat exchanger 29, and finally the supply air receives heat by the heat insulating means 25 to the negative electrode side of the solid electrolyte 1. It reaches.

Therefore, cold outside air does not come to the negative electrode side of the solid electrolyte 1. Then exhaust passage 3
2 is discharged to the outside. At this time, the air passing through the air supply passage 31 by the heat exchanger 29 obtains heat from the air passing through the exhaust passage 32.

  A gas mixing means 35 is connected to the positive electrode side of the container 33 in which the oxygen pump element is accommodated via a vent 34. The mixing means 35 includes a gas induction pipe 36, a mixed gas introduction pipe 37, a gas mixer 38, and a gas pump 39.

  About the oxygen supply apparatus comprised as mentioned above, the starting operation and effect | action are demonstrated below.

  When electric power of about 400 W is applied to the heating unit 16 by the second voltage applying unit 19, the temperature of the solid electrolyte 1 in the heat insulating units 25 and 26 is rapidly increased.

  When it is detected that the temperature in the vicinity of the solid electrolyte has reached about 600 ° C. in about 40 seconds, the second voltage control means 18 controls the second voltage application means 190 so that the input to the heating means 16 is up to about 100 W at 50V. Decrease at once and leave for 20 seconds. At that time, the 36 solid electrolytes 1 had a temperature difference of about 150 ° C. when the temperature reached 600 ° C. due to the arrangement relationship with the heating means 16.

  However, cooling is performed inside the casing having heat insulation properties, and individual temperature differences are gradually converged to reach about 50 ° C. at the maximum. At this time, when a voltage of 28 V is applied to the oxygen pump element by the first voltage applying means 14, oxygen ions are conducted inside the solid electrolyte, and the current value increases. When the current value reaches 4.0 A, the voltage applied to the oxygen pump element is reduced to 22V. Thereafter, the input to the heating means 16 is reduced to about 40 V and 60 W so that the oxygen pump element maintains a current value of 4.0 A at a voltage of 22 V.

  FIG. 5 shows a temperature change diagram and a control mode for the solid electrolyte when the oxygen pump element is activated. The temperature change with respect to the solid electrolyte indicates the maximum temperature and the minimum temperature, and this difference becomes a temperature unevenness occurring between the solid electrolytes. In the present embodiment, it takes about 70 seconds for the oxygen pump element to reach a predetermined current value of 4.0 A.

  When a voltage is applied to each solid electrolyte through the positive second electrode film and the negative second electrode film when the temperature at which the solid electrolyte can conduct ions is reached, oxygen near the surface on the negative electrode film side becomes oxygen. By the electrochemical reaction, the inside of the solid electrolyte moves from the negative electrode film to the positive electrode film as oxygen ions, and is released as oxygen molecules from the surface on the positive electrode film side. When a current of 4.0 A flows through the 36 oxygen pump elements made of solid electrolyte, oxygen gas of about 520 ml / min can be obtained from the positive electrode side of the oxygen pump element.

  At this time, by starting the blower pump 28 as well, a predetermined amount of outside air is guided to the vent hole 27 via the air supply passage 31 and finally supplied to the negative electrode side of the solid electrolyte 1 while receiving heat by the heat insulating means 25. Is done. Here, 3200 ml / min of air was supplied. When the oxygen pump element is operating, oxygen is extracted from the negative electrode side of the solid electrolyte 22 to the positive electrode side, and the negative electrode side falls into a nitrogen-rich state.

  In order to suppress this, the air in the nitrogen-rich state is discharged to the outside through the exhaust passage 32, and new air is continuously supplied from the air supply passage 31. At this time, the air passing through the air supply passage 31 by the heat exchanger 29 obtains heat from the air passing through the exhaust passage 32. The heat recovery rate by the heat exchanger 29 was designed to be about 50%. Here, copper fins were used as heat exchange members. Thus, by providing a blower circuit having a supply / exhaust mechanism including a heat exchanger on the negative electrode side of the oxygen pump element, an oxygen supply device having a large oxygen pump flow rate can be provided with low power consumption.

  At this time, the metal foil member is also exposed to a high temperature state in addition to the atmospheric temperature of 600 ° C., but excellent oxidation resistance can be obtained by using a ferritic stainless steel containing aluminum.

  The vicinity of the surface on the positive electrode film side becomes a state close to pure oxygen by the generated oxygen gas, and is separated from the surface on the positive electrode side and passes through the heat insulating means 26 having air permeability. Therefore, the metal foil member 6 and the gas sealant 12 serving as means for partitioning the space effectively act as means for preventing gas leakage from the negative electrode film side. Further, the portion where the solid electrolyte 1 and the metal foil member 6 are gas-sealed also effectively acts as a means for preventing gas leakage from the negative electrode film side.

  The oxygen gas released from the positive electrode side passes through the vent 34 and is mixed with the mixed gas by the gas induction pipe 36, the mixed gas introduction pipe 37, and the gas mixer 38 that constitute the gas mixing means 35. The In this embodiment, the mixed gas is the atmosphere. The generated mixed gas is an oxygen-enriched gas, and its flow rate is determined by the suction and discharge speed of the gas pump 39.

  The oxygen concentration in the mixed gas is determined by the mixed gas flow rate and the amount of oxygen ions flowing through the solid electrolyte, that is, the magnitude of the ionic current.

(Comparative form 1)
Also in this comparative embodiment, the same oxygen supply apparatus as that in Embodiment 1 was used. The starting method at that time will be described.

  When power of about 200 W was applied to the heating means 16 at 70 V by the second voltage applying means 19, it was detected that the temperature in the vicinity of the solid electrolyte reached about 500 ° C. in about 60 seconds. At that time, the temperature difference generated between the individual solid electrolytes reached a maximum of 110 ° C.

  Accordingly, rather than applying a voltage to the solid electrolyte when a predetermined temperature is reached while applying a constant power to the heating means 16, the maximum power is applied to the heating means to overshoot the predetermined temperature, and then The method of applying a voltage to the solid electrolyte with a cooling time clearly can suppress temperature unevenness. This is because the temperature unevenness generated from the heating means 16 and the temperature unevenness generated from the layout of the solid electrolyte are added together. On the other hand, in the state where the input of the heating means 16 is suppressed, the maximum temperature is naturally the central portion, and gradually has a temperature gradient from there.

  By reducing the temperature unevenness as much as possible, the risk of cracking even when an excessive current is passed through the solid electrolyte can be greatly reduced. When the oxygen pump element is composed of a plurality of solid electrolytes, temperature unevenness of individual solid electrolytes is inevitable. By performing control to reduce temperature unevenness as much as possible under such conditions, the risk of causing the solid electrolyte to crack can be avoided.

  In the first embodiment, the voltage to the heating means 16 is lowered from 100V corresponding to the voltage a to 50V corresponding to the voltage b, and left for 20 sec. Therefore, if left for 30 seconds, the temperature unevenness is further reduced. However, the time until oxygen supply is delayed by the amount of time left. Therefore, it is necessary to make a compromise in view of the temperature unevenness of the solid electrolyte after leaving the voltage b.

  In the first embodiment, 36 solid electrolytes 1 are used. However, it is necessary to consider depending on the number of sheets used.

(Embodiment 2)
Also in this embodiment, the same oxygen supply apparatus as that in Embodiment 1 was used. The starting method at that time will be described.

  When electric power of about 480 W is applied to the heating means 16 by the second voltage applying means 19 at 110 V, the temperature of the solid electrolyte 1 in the heat insulating means 25 and 26 increases rapidly.

  When it is detected that the temperature in the vicinity of the solid electrolyte 1 has reached about 700 ° C. in about 40 seconds, the second voltage control means 18 controls the second voltage application means 19 to stop the input to the heating means 16 and 20 seconds. Leave for a while. At that time, the 36 solid electrolytes 1 had a temperature difference of about 130 ° C. when the temperature reached 700 ° C. due to the arrangement relationship with the heating means 16.

However, it is cooled inside the heat-insulating housing, and the temperature difference is gradually converged to reach a maximum of about 40 ° C. At this time, when a voltage of 25 V is applied to the oxygen pump element by the first voltage applying means 14, oxygen ions are conducted inside the solid electrolyte, and the current value increases. When the current value reaches 4.0 A, the voltage applied to the oxygen pump element is reduced to 20V.
At this time, the blower pump 28 is also activated, whereby a predetermined amount of outside air is guided to the vent hole 27 through the air supply passage 31 and supplied to the negative electrode side of the solid electrolyte 1.

  However, since only the oxygen pump element is a heat source inside the heat insulating means 25 and 26, the temperature of the solid electrolyte 1 gradually decreases thereafter. Therefore, in order to maintain the current value of the oxygen pump element at 4.0 A, it is necessary to increase the voltage from 20V to a maximum of 33V.

  At this time, the oxygen supply device reached a heat balanced state by the amount of heat generated by the oxygen pump element. When the oxygen pump element is started, the solid electrolyte and the vicinity thereof are considerably hot, so that the applied voltage c is 20 V. However, when the oxygen supply device is stabilized only by the amount of heat of the oxygen pump element, the applied voltage d is 33 V. It was necessary. Therefore, the relationship of voltage c <voltage d is established.

  FIG. 6 shows a temperature change diagram and a control mode for the solid electrolyte when the oxygen pump element is activated. The temperature change with respect to the solid electrolyte indicates the maximum temperature and the minimum temperature, and this difference represents the temperature unevenness occurring between the solid electrolytes. In the present embodiment, it takes about 70 seconds for the oxygen pump element to reach a predetermined current value of 4.0 A, and it finally reaches the heat balanced state after 8 minutes.

(Embodiment 3)
7 and 8 show an oxygen pump element according to the third embodiment, and the details of the configuration that performs the same operation as in the first embodiment are the same as those in the first embodiment.

  The configuration of the first electrode film and the second electrode film formed on the surface of the solid electrolyte 38 is the same. The dimensions of the solid electrolyte 38 are 32 × 32 mm and the thickness is 120 μm. Here, the positive electrode film and the negative electrode film are divided into four parts on one solid electrolyte 38. The dimension of one positive electrode film and negative electrode film was 13 × 13 mm, and the interval between adjacent electrode films was 1 mm. The metal foil member 39 is the same as that of the first embodiment, and nine openings 29 × 29 mm are provided.

An insulating film 40 is disposed around the opening that is in a bonding relationship with the solid electrolyte 38. The dimensions are an outer dimension of 33 × 35 mm and an inner dimension of 29.5 × 29.5 mm so that a part of the lead extraction portion can be formed. Further, a conductive film is disposed on the insulating film while maintaining an insulating relationship with the metal foil member 39.

  The positive second electrode film 41 and the negative second electrode film 42 divided into four are configured to be electrically connected in series. 7 and 8, individual solid electrolytes are numbered in a potential sequence connected to a series circuit.

  Specifically, three through holes 43 are arranged at the center line position of one solid electrolyte, and the positive second electrode film is electrically connected to the negative second electrode film located on the opposite side by using the through holes. It is connected to. The first negative second electrode film is a second positive second electrode film located next to the first negative second electrode film, and the second negative second electrode film is a third positive second electrode film using a through hole located in the center. The third negative second electrode film is connected to the adjacent fourth positive second electrode film.

  The fourth negative second electrode film is joined and connected to the conductive film 44 in which the solid electrolyte 38 is disposed on the metal foil member 39, and the conductive film 44 is provided with a portion protruding from the solid electrolyte 38. Is connected to the fifth positive second electrode film of the solid electrolyte 38 located adjacent to the gold electrode 45 by the gold wire 45. A voltage is applied to the lead portion 46 connected to be sequentially connected in the same manner and finally connected to the lead portion 46 connected to the first positive second electrode film and the 36th negative second electrode film. Thus, the oxygen pump element is operated.

  An oxygen supply device similar to that in Embodiment 1 was produced, and the oxygen pump element was operated. When power of about 400 W is applied to the heating means by the voltage applying means at 100 V, the temperature of the heat insulating means and the solid electrolyte in the heat insulating means rapidly increases. When it is detected that the temperature in the vicinity of the solid electrolyte has reached about 600 ° C. in about 40 seconds, the voltage application means is controlled by the voltage control means, the input to the heating means is reduced to about 100 W at 50 V, and left for 20 seconds. .

  At that time, the nine solid electrolytes had a temperature difference of about 120 ° C. when the temperature reached 600 ° C. due to the arrangement relationship with the ribbon heater, but they were cooled inside the casing having heat insulation properties, and the temperature difference gradually increased. The maximum temperature is about 40 ° C. At this time, when a voltage of 32 V is applied to the oxygen pump element by voltage application means, oxygen ions are conducted inside the solid electrolyte, and the current value increases.

  When the current value reaches 4.0 A, the voltage applied to the oxygen pump element is reduced to 24V. Thereafter, the input to the ribbon heater is reduced to about 40 V and 60 W so that the oxygen pump element maintains a current value of 4.0 A at a voltage of 24 V.

  As a result, it is possible to obtain about 520 ml / min of oxygen gas from the positive electrode side of the oxygen pump element by oxygen ion conduction. In addition, air supply of 3200 ml / min was performed on the negative electrode side of the oxygen pump element.

  Therefore, the device voltage can be increased by dividing the electrode film with a single solid electrolyte to form a series circuit, and using nine solid electrolytes, the same performance with the same current value as in the first embodiment. Could get. Since nine solid electrolytes are arranged on the metal foil member, and the gold wire and the lead part are connected to the seven, the manufacturing process is simplified as compared with the first embodiment.

  In the embodiment, a method of indirectly heating the solid electrolyte with a ribbon heater is used as the heating means. In order to lead the solid electrolyte to a temperature at which oxygen ions can be conducted rapidly, it is most efficient to add a large input to the ribbon heater, and the response when variable can be made very good.

  In the embodiment, the inorganic porous film on the surface of the ribbon heater is made of ZrO2 particles and TiO2 particles made of SiO2 sol. However, the present invention is not limited to this. In addition, TiO2 and Al2O3 can be used. The inorganic porous film may be any film that can withstand the rigidity when the ribbon heater is thermally expanded. By forming the inorganic porous film on the surface of the ribbon heater, it was possible to rapidly heat the solid electrolyte by about 20% compared to the case without the inorganic porous film.

  In the embodiment, lanthanum gallate is used as the solid electrolyte. However, the present invention is not limited to this, and yttrium-doped zirconia (YSZ), samarium-doped ceria (SDC), or the like may be used. However, at present, the lanthanum gallate material is the most preferable material in view of the durability of the material because the operating temperature is low as an oxygen ion conductor.

In the embodiment, Sm _0.5 Sr _0.5 CoO ₃ is used as the composite metal oxide of the first electrode film, but the present invention is not limited to this. However, since the composite metal oxide having a perovskite structure has high electrode reactivity with oxygen molecules and itself has conductivity, excellent oxygen ion conductivity can be realized. Particularly, among the perovskite complex oxides, those 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, and a part of the A site is replaced by strontium It had excellent conductivity and high oxygen molecule electrode reactivity.

  In the embodiment, Fe-20Cr-5Al, which is a ferritic stainless steel containing aluminum, is used as the metal foil member. However, the present invention is not limited to this, and a material having durability against high-temperature oxidation is used. Other metal foil materials can be used if present. However, at present, ferritic stainless steel containing aluminum has excellent characteristics against high-temperature oxidation.

  Furthermore, it is possible to add a rare earth metal for the purpose of improving the high temperature oxidation resistance. Moreover, although 12 micrometers in thickness was used, it is thought that 5-20 micrometers is preferable as a metal foil member. That is, in order to prevent the heat generated in the solid electrolyte from being transferred to the outer peripheral portion, the thinner the thickness, the better. However, if the thickness is 5 μm or less, the handling at the time of manufacture becomes worse.

  Further, in the embodiment, as a configuration of the metal foil member, only the case where the solid electrolyte is used as a partitioning means for partitioning the space by being bonded to the negative electrode film side has been described. It may be used as a partitioning means for partitioning the space portion.

  In the embodiment, Au-based materials are used as the second electrode film and the conductive film. However, the present invention is not limited to this, and any other Ag-based material or AgPd-based material can be used as long as it has a low heat resistance and heat resistance. Things can be used.

  In the embodiment, the case where the second electrode film is further disposed on the positive electrode film and the negative electrode film on the surface of the solid electrolyte has been described. However, the present invention can be applied to a structure in which the second electrode film is not disposed. For example, if the size of the electrode film formed on the surface of the solid electrolyte is 5 × 5 mm, the flowing current value is about 0.5 A, and the potential unevenness generated on the electrode film is not so large, so the second electrode film is necessary. Don't be.

As described above, the method for controlling an oxygen supply apparatus according to the present invention can be applied to an oxygen pump element using a solid electrolyte, and can be applied to a wide range of devices such as an air purifier, an air conditioner, a health promotion device, and a health promotion device using oxygen supply. Can be used for various purposes.

1 is a cross-sectional configuration diagram of a solid electrolyte serving as an oxygen pump element in Embodiment 1 of the present invention. Schematic configuration diagram of the oxygen pump element Schematic cross-sectional configuration diagram of the oxygen supply device External view of the ribbon heater as the heating means Temperature change chart and control mode chart when starting the oxygen pump element Temperature change diagram and control mode diagram at the time of starting the oxygen pump element in the second embodiment of the present invention Schematic block diagram of the positive electrode side of the oxygen pump element in the third embodiment of the present invention Schematic configuration diagram on the negative electrode side of the oxygen pump element Schematic configuration diagram of a conventional oxygen pump element Schematic configuration diagram of another conventional oxygen pump element Schematic configuration diagram of another conventional oxygen pump element Schematic sectional view of another conventional oxygen pump element

Explanation of symbols

1,38 Solid electrolyte 2,41 Positive electrode membrane (first electrode membrane)
3,42 Negative electrode film (first electrode film)
6, 39 Metal foil member 7, 40 Insulating film 8, 44 Conductive film 14 First voltage application means 15 First voltage control means 16 Heating means 18 Second voltage control means 19 Second voltage application means 25, 26 Heat insulation means 28 Blower Pump 29 Heat exchanger 30 Blower circuit 31 Air supply passage 32 Exhaust passage 35 Mixing means

Claims (11)

An oxygen pump element comprising at least a solid electrolyte; first voltage applying means for applying a voltage to the oxygen pump element; first voltage control means for controlling the first voltage applying means; and heating the oxygen pump element. A heat insulating housing that houses the oxygen pump element and the heating means; a heating means; a second voltage applying means for applying a voltage to the heating means; a second voltage control means for controlling the second voltage applying means; The solid electrolyte, once heated, is lowered by changing the applied voltage to the voltage b after the voltage a is applied by the second voltage control means for a predetermined time at the time of startup. At the time of transition, the oxygen pump element is activated by applying a predetermined voltage by the first voltage applying means, and the relationship between the voltage a and the voltage b at this time is set to voltage a> voltage b. Apparatus. An oxygen pump element comprising at least a solid electrolyte; first voltage applying means for applying a voltage to the oxygen pump element; first voltage control means for controlling the first voltage applying means; and heating the oxygen pump element. A heat insulating housing that houses the oxygen pump element and the heating means; a heating means; a second voltage applying means for applying a voltage to the heating means; a second voltage control means for controlling the second voltage applying means; And when the voltage a is applied by the second voltage control means for a predetermined time at the start-up, and then the voltage application is stopped, so that the temperature of the solid electrolyte once increased is reduced, After being activated by applying a predetermined voltage c to the oxygen pump element by the first voltage applying means, the first voltage applying means maintains the operating state at a predetermined current value. Finally migrated to steady state in to voltage d the voltage applied Te, oxygenator in which the relationship between the voltage c and the voltage d at this time the voltage c <voltage d. The oxygen pump element is provided with a plurality of openings in a metal foil member, and a plurality of oxygen ion conductive solid electrolytes are gas-sealed through the insulating film in the openings, and the metal foil member is a space. A positive electrode film and a negative electrode film are formed on both surfaces of the solid electrolyte, and a plurality of solid electrolytes are configured such that the positive electrode film and the negative electrode film are electrically connected in series. The oxygen supply apparatus according to claim 1 or 2, wherein In one solid electrolyte, a positive electrode film and a negative electrode film are arranged in a pair structure in which a capacitor is formed by dividing the positive electrode film and the negative electrode film so that the positive electrode film and the negative electrode film are electrically connected in series. The oxygen supply device according to any one of claims 1 to 3, wherein the oxygen supply device is configured as follows. The oxygen supply device according to any one of claims 1 to 4, wherein a blower circuit having a supply / exhaust mechanism including a heat exchanger is disposed on a negative electrode side of the oxygen pump element. The oxygen supply apparatus according to any one of claims 1 to 5, wherein the heating means comprises a ribbon heater. The oxygen supply device according to claim 6, wherein the surface of the ribbon heater is covered with an inorganic porous film. The oxygen supply apparatus according to claim 7, wherein the inorganic porous film is mainly composed of ZrO2, TiO2, Al2O3, and SiO2. The positive electrode film and the negative electrode film are composed of a first electrode film directly bonded to a solid electrolyte and a second electrode film formed on the first electrode film, and a composite metal oxide component is formed on the solid electrolyte. 9. The film according to claim 3, wherein a film mainly composed of the first electrode film and a film mainly composed of a noble metal component are disposed on the first electrode film as the second electrode film. The oxygen supply device according to item. The oxygen supply apparatus according to any one of claims 1 to 9, wherein the solid electrolyte is a lanthanum gallate system. The oxygen supply device according to any one of claims 3 to 10, wherein the metal foil member is ferritic stainless steel containing aluminum.