JPS60259949A - Electrochemical element and apparatus - Google Patents

Abstract

PURPOSE:To reduce effect of a pump voltage on a sensor electromotive force and aging with an excellent response by arranging an electrochemical pump cell and an electrochemical sensor cell to insulate solid electrolytic layers thereof electrically from each other with a high resistance ceramic layer. CONSTITUTION:An oxygen pump cell 2 and an oxygen concentration detection cell 4 are laminated through a high resistance ceramics layer 6 and sintered integrally. The cell 2 having a porous solid electrolytic layer 8 with a predetermined diffusion resistance is equipped with an outer pump electrode 10 on the surface exposed to gas to be measured such as exhaust gas while an inner pump electrode 12 is provided at the position corresponding to the electrode 10. The cell 4 has an airtight solid electrolytic layer 16 and an outer reference electrode 18 to be brought into contact with a reference gas is joined with a measuring electrode 20. The electrode 20 is made common to an electrode 12 and the electrodes 20 and 18 are connected to a measuring device 22. The layer 6 has a notch hole 24 at the position corresponding to the electrode 12. This can reduce effect of pump voltage on a sensor electromotive force and aging with an excellent response.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrochemical element and apparatus, and more particularly to an element and apparatus constituted by a stacked electrochemical cell using a solid electrolyte.

Conventionally, oxygen ion conductive solid electrolytes such as zirconia porcelain have been used in devices constructed with electrochemical elements using solid electrolytes, such as oxygen sensors that detect the oxygen concentration in the exhaust gas of automobile internal combustion engines. Sensors that measure oxygen concentration using the principle of an oxygen concentration battery are known. Further, electrochemical devices (elements) such as hydrogen, nitrogen, carbon dioxide, etc. detectors and pumps that utilize the same concentration cell principle as the oxygen sensor are also known. Until now, solid electrolytes used in the electrochemical elements of such devices have generally had a cylindrical shape with a bottom, but in recent years, several types of solid electrolytes have been developed to cover a wider range of applications. A stacked structure in which an electrochemical cell is constructed by using a solid electrolyte layer and providing a predetermined electrode in contact with the surface of the solid electrolyte has been studied.

By the way, as one such electrochemical element having a laminated structure, a plurality of electrochemical cells each having porous electrodes on both sides of a solid electrolyte are combined, and one of them is used as an electrochemical pump cell. It is also known that the other one is configured as an electrochemical sensor cell, but such an element has a laminated structure that is integrally sintered with a solid electrolyte interposed in between. When an attempt is made to apply a predetermined voltage to the pump cell section, specifically the pump electrode, to perform the pump function, the applied voltage leaks to the other sensor cell section and affects the electromotive force of the sensor cell. There was a problem that this caused measurement errors.

Furthermore, as shown in 5AE810433, an electrochemical device having two such electrochemical cells has a cavity located between the cells and has a predetermined diffusion resistance. Some structures have been disclosed in which a diffusion hole (pinhole) is provided and the cavity is communicated with the external gas atmosphere to be measured through the diffusion hole. In devices with a structure in which a cavity communicates with the outside, deposits such as soot may accumulate on the inner wall of the pinhole, changing its diffusion resistance, and if the cavity has a predetermined thickness inside. Since it is necessary,
There were problems such as insufficient responsiveness.

The present invention has been made against this background, and aims to provide excellent responsiveness, prevent the pump voltage from affecting the sensor electromotive force, and prevent deposits from forming on the sensor. and for this purpose, a pair of porous first and second electrodes are disposed on the surface of an ion-conducting solid electrolyte layer that is at least partially porous. a first electrochemical cell; a second electrochemical cell having a pair of porous third and fourth electrodes on the surface of an airtight ion-conducting solid electrolyte layer; interposed between at least the (porous) ionically conductive solid electrolyte layer of the first electrochemical cell and the (airtight) ionically conductive solid electrolyte layer of the second electrochemical cell. a laminated structure including a high-resistance ceramic layer that insulates the second electrochemical cell, and the second electrode of the second electrochemical cell and the third electrode of the second electrochemical cell are substantially insulated. The electrochemical elements were constructed so that they were exposed to the same atmosphere.

Therefore, according to the present invention, since the solid electrolyte layers of at least two electrochemical cells used as a pump cell and a sensor cell are electrically insulated by a high-resistance ceramic layer, a predetermined distance is provided between the electrodes of the pump cell. Even when a pump voltage is applied, no current leaks to the sensor cell side, and therefore the problem of the electromotive force of the sensor cell being affected can be effectively solved.

In addition, since a porous ion-conducting solid electrolyte layer is used as a gas diffusion layer in the first electrochemical cell, changes in diffusion resistance due to deposits are reduced, making it possible to obtain an element with little change over time. It became possible.

Furthermore, since there is no need for a cavity with a predetermined thickness inside, it was possible to obtain an element with excellent responsiveness.

Hereinafter, in order to clarify the present invention more specifically, the configuration of the present invention will be explained in detail based on embodiments shown in the drawings.

First, FIG. 1 shows an expanded view of the basic structure of an oxygen concentration detection element, which is a specific example of an electrochemical element according to the present invention. That is, in this oxygen concentration detection element (oxygen sensor), an oxygen pump cell 2 as a first electrochemical cell and an oxygen concentration detection cell (sensor cell) 4 as a second electrochemical cell are porous and have high resistance. Ceramic layer 6
It has a structure in which the sensors are laminated, sintered, and integrated through the layers, and is one of the so-called lean burn sensors.

The oxygen pump cell 2 constituting this element has a porous flat plate-shaped oxygen ion conductive solid electrolyte layer 8 made of itria-doped zirconia porcelain, etc. An outer pump electrode (first electrode) 10 of a porous layer made of, for example, platinum and yttria-doped zirconia is provided on the surface exposed to the gas to be measured, while the other surface (inner surface) of the porous solid electrolyte layer 8 is provided. ) is provided with an inner pump electrode (second electrode) 12 made of the same material as the outer pump electrode 10, that is, made of porous platinum-zirconia, at a position corresponding to the outer pump electrode 10. and those pump electrodes 1
0.12 are connected to an external power source 14 through their respective lead portions, and a predetermined voltage is applied between these electrodes.

Note that the porous solid electrolyte layer 8 of the oxygen pump cell 2
has a function as a diffusion layer that allows the component to be measured (oxygen in this case) in the gas to be measured to diffuse from one surface to the other through its open pores with a predetermined diffusion resistance. There is. In addition, this porous solid electrolyte layer 8 has a portion that is in contact with the inner pump electrode 12 functioning as a diffusion layer, and the other portions do not necessarily have to be porous and must be an airtight solid electrolyte. Good too. In an electrochemical cell constituted by a pair of electrodes 10 and 12 provided in contact with the solid electrolyte layer 8 and its outer and inner surfaces, respectively, a voltage is applied between these electrodes 10.1'2. By using a predetermined DC voltage, as is well known, and at a rate proportional to the amount of electricity of the DC, the oxygen in the gas to be measured, which has been led to the inner pump electrode 12 side by the above-mentioned diffusion, is electrochemically Due to the pump action, the gas is transferred to the outer pump electrode 10 side and released into the gas to be measured.

Further, the oxygen concentration detection cell 4 is connected to the oxygen pump -Iy-
The two models are different in that an airtight flat solid electrolyte layer 16 made of zirconia porcelain doped with ittria is used as the solid electrolyte layer. Outer reference electrode (fourth electrode) 1 brought into contact with reference gas of oxygen concentration
8, and the inner pump electrode 12 of the oxygen pump cell 2
By joining a measurement electrode (third electrode) 20 exposed to the atmosphere existing around the electrode, an electrochemical cell as an oxygen concentration battery is constructed.

Note that here, this measurement electrode 20 is a common electrode with the inner pump electrode 12.

The measuring electrode 2o and the reference electrode 18 are each guided to the outside by a lead part and installed in a predetermined measuring device (
It is connected to a potentiometer (potentiometer) 22 to measure the potential between these electrodes. That is, in this oxygen concentration detection cell 4, the reference electrode 18 is brought into contact with the reference gas, and the atmosphere around the inner pump electrode 12 of the oxygen pump cell 2, which contains a controlled amount of oxygen from the gas to be measured, is brought into contact with the reference electrode 18. A predetermined electromotive force based on the difference in oxygen concentration in these gases is measured between the gas and the measuring electrode 2o.

Note that the electrodes 10.12 of the oxygen pump cell 2 are preferably disposed facing each other as shown in FIG. 1 in order to lower the pump impedance, but the electrodes (20) of the oxygen concentration detection cell 4 are , 18 do not necessarily have to face each other.

Further, the high-resistance ceramic layer 6 is formed of porous alumina or high-resistance porcelain described in Japanese Patent Application No. 58-239956, and the inner pump electrode 1
2 (measuring electrode 20), and the electrode accommodated in this notch hole 24 acts as the inner pump electrode 12 for the oxygen pump cell 2, On the other hand, the oxygen concentration detection cell 4 is configured to function as a measurement electrode 20.

Then, the oxygen pump cell 2 and the oxygen concentration detection cell 4 are stacked and sintered with such a high-resistance ceramic layer 6 in between, and are integrated, thereby constructing the intended electrochemical device. It will be done.

In addition, in the basic structure of the electrochemical element shown in FIG. 1, the inner pump electrode 1 of the oxygen pump cell 2
2 and the measurement electrode 20 of the oxygen concentration detection cell 4 are used as a common electrode, which simplifies the structure and provides an economically advantageous structure, but as shown in FIG. It is also possible to adopt a basic structure in which the inner pump electrode 12 and the measurement electrode 20 are separate bodies, and by adopting such a separate and independent electrode structure,
Low-temperature operability is improved and hysteresis characteristics can be reduced.

In FIG. 2, unlike in FIG. 1, the porous solid electrolyte layer 8
is used for the oxygen concentration detection cell 4, and the hermetic mass electrolyte layer 16 is used for the oxygen pump cell 2, and it goes without saying that they function well as in FIG. 1.

In addition, a thin porous high-resistance ceramic layer 6 is interposed between the independent and separate inner pump electrode 12 and the measurement electrode 20. , the atmosphere surrounding the inner pump electrode 12 is brought into contact with the measuring electrode 20 . Since the inner pump electrode 12 and the measurement electrode 20 are generally grounded together, their lead parts are connected in the middle to integrate them and taken out to the outside as a single lead part. It is also possible to create a structure like this.

Note that the inner pump electrode 12 and the measurement electrode 20 do not necessarily need to be insulated, and the high-resistance ceramic layer 6 does not need to be interposed therebetween. For example, as shown in FIG. 3, an airtight high-resistance ceramic layer having a notch 24 between the inner pump electrode 12 and the measurement electrode 20 is used to form a porous solid electrolyte layer B and an airtight solid electrolyte layer 16. insulate and
In addition, between the inner pump electrode 12 and the measurement electrode 20, a thin porous ceramic layer 2 such as porous zirconia is provided.
5 may be present.

Therefore, in the electrochemical element having the structure shown in FIGS. 1 to 3, the porous solid electrolyte layer 8 is
A high-resistance ceramic layer 6 is provided between the solid electrolyte layer 16 and the solid electrolyte layer 16.
Because of the presence of the Since current leakage is effectively blocked by the high-resistance ceramic layer 6, the electromotive force of the oxygen concentration detection cell 4 is not substantially affected by the pump voltage. Therefore, problems such as measurement errors do not occur, and the device has excellent air-fuel ratio detection range and detection accuracy.

In addition, the porous solid electrolyte layer B of the oxygen pump cell 2 functions as a diffusion layer, so that the oxygen in the outside gas to be measured is
It is diffused to the inner pump electrode 12 side through the fine porous structure of the porous solid electrolyte layer 8, and since a conventional pinhole is not used as a diffusion path, there is no change in diffusion resistance due to deposits. Since the inner pump electrode 12 and the measurement electrode 20 are close to each other or are common, the element has good responsiveness.

In an electrochemical element with such a structure,
The oxygen partial pressure (concentration) in the atmosphere brought into contact with the measurement electrode 20 of the oxygen concentration detection cell 4 is controlled by the oxygen pump function of the oxygen pump cell 2 and the diffusion resistance of the porous solid electrolyte layer 8 as a diffusion layer. Since the oxygen partial pressure in the measurement atmosphere can be lower than the actual oxygen partial pressure of the measured gas, it is useful for controlling engines that generate exhaust gas in a lean atmosphere where the oxygen partial pressure is higher than the oxygen partial pressure of the stoichiometric air-fuel ratio. , is preferably used.

Of course, such an electrochemical element is used not only as a lean burn sensor as described above, but also as a measurement target gas such as exhaust gas in a neutral atmosphere where the oxygen partial pressure is approximately equal to the oxygen partial pressure of the stoichiometric air-fuel ratio. By reversing the direction of the current flowing through the pump cell 2, it can be used as a rich burn sensor, etc., which uses exhaust gas in a lean atmosphere where the oxygen partial pressure is lower than the oxygen partial pressure of the stoichiometric air-fuel ratio as the measured gas. In either case, the oxygen (measurement component) concentration or excess fuel concentration of the target gas to be measured can be determined according to a known measurement method.

In addition to the above-mentioned zirconia porcelain which is suitably employed as the solid electrolyte layer 8.16 of the present invention, aluminum nitride, 5rCeO3, Biz 03-rare earth oxide solid solution, La I-x Cax YO: As mentioned above, the porous solid electrolyte layer 8 has a portion in contact with the inner pump electrode 12 or the measurement electrode 20 that extends from one surface to the other. At least this part needs to be a porous layer that penetrates in the thickness direction, since the side surface of the porous layer functions as a diffusion layer that can diffuse the measurement component in the gas to be measured with a predetermined diffusion resistance.

Such a porous layer will have an appropriate porosity depending on the required degree of diffusion resistance, but the optimum open porosity will also vary depending on the manufacturing method of the porous layer. When using the mercury intrusion method, 2 to 3
It is preferably about 0%, and in the case of plasma spraying, it is preferably about 0.5 to 10% when measured by the mercury method.

Further, the solid electrolyte layer 16 needs to be more airtight than the porous solid electrolyte layer 8 as a diffusion layer, but it does not necessarily have to be a completely airtight layer, and may be exposed to the surrounding atmosphere such as in the gas to be measured. Even if the component to be measured (oxygen) present is permeable to a certain extent, it is guided by diffusion within the porous solid electrolyte layer 8 as a diffusion layer and passes through the inner pump electrode 12 (
It is sufficient that the airtightness is such that it does not adversely affect the atmosphere formed around the measuring electrode 20), in other words, it does not adversely affect the measurement of the electromotive force by the measuring electrode 20.

The high-resistance ceramic layer 6 interposed between the oxygen pump cell 2 and the oxygen concentration detection cell 4 is generally preferably a ceramic layer containing alumina or spinel as a main component; There is no problem in using ceramic materials whose main components are mullite, steatite, forsterite, cordierite, zircon, etc., and a high-resistance ceramic layer is formed with such ceramic materials. However, such a ceramic layer is generally porous and desirably formed as a thin layer.
Usually, when the porosity is about 10% to 30%, it is 300%.
It will be formed as a layer with a thickness of less than μm, preferably about 5 to 50 μm. However, as mentioned above, this high-resistance ceramic layer 6 may be an airtight layer having notched holes.
If the high-resistance zirconia material described in No. 956 is used, it is possible to form an airtight high-resistance layer.

Additionally, a porous ceramic layer 25 interposed between the inner pump electrode 12 and the measurement electrode 20 as shown in FIG.
As long as it is porous, a high-resistance ceramic layer or a porous solid electrolyte can be used without limitation.

Furthermore, when forming the oxygen pump cell 2, oxygen concentration detection cell 4, and high-resistance ceramic layer 6, and laminating them, the solid electrolyte 8, 16 constituting each cell is
The electrodes and their lead parts are printed on the raw material by screen printing, etc., and the ceramic powder paste that becomes the high-resistance ceramic layer is printed on either cell side (in this case, on the oxygen concentration detection cell 4 side). After that, the cells 2.4 can be superimposed to form the intended electrochemical element, and the whole can be sintered and integrated using a known simultaneous integral sintering method. Although preferred for improving strength, it is also possible to form an electrochemical device by sintering the laminate except for the porous solid electrolyte layer, and then forming a porous solid electrolyte layer by a known plasma spraying method.

In addition, when forming the intended electrochemical element by a method such as simultaneous integral sintering, each electrode 10, 1
2, 18, 20 and their lead parts are preferably fired at the same time. In that case, those electrodes and lead parts are made of platinum, palladium, rhodium,
It is desirable to print using a material mainly composed of platinum group metals such as iridium, ruthenium, and osmium, and to form electrodes or lead portions by firing the material. In addition, in order to prevent such peeling and disconnection of the electrodes and leads, fine powders such as zirconia and alumina are mixed into the electrodes and leads, and when they are fired, they do not come in contact with them. It is desirable to improve the integration with the layers.

The electrochemical device according to the present invention has a basic form as shown in FIGS. 1 to 3, but various improvements have been made in the structure while maintaining this basic form. Variations can be made, some examples of which are shown in FIGS. 4-9.

First, the electrochemical element shown in FIGS. 4 and 5 is
This is a modification of the device shown in FIG. 1 in which the inner pump electrode 12 and the measurement electrode 20 are used as a common pole, and has three major features different from the device shown in FIG.

That is, one of the major features is that a porous alumina layer 28 as an electrode protection layer is laminated on the surface of the porous solid electrolyte layer 8 constituting the oxygen pump cell 2 on the side where the outer pump electrode 10 is formed. Furthermore, an airtight ceramic layer 26 such as a zirconia layer is laminated thereon. A notch hole 30 is provided in a portion of the airtight ceramic layer 26 corresponding to the outer pump electrode 10, and this hole 30 allows the outer pump electrode 10 to be viewed from a direction perpendicular to the electrode surface. The gas to be measured is guided through the porous alumina layer 28. In other words, by providing the airtight ceramic layer 26 as a gas introduction direction control layer, which is made of airtight ceramic socks, around the outer pump electrode 10, the gas to be measured is prevented from entering from the side. ,
The gas to be measured can be diffused in the porous solid electrolyte layer 8 as a diffusion layer through the outer pump electrode 10 only from the direction perpendicular to the electrode surface.
As a result, the amount of diffusion of the gas to be measured in the inner pump electrode 12 is made uniform.

The second feature is that an airtight U-shaped spacer member 31 and a plate-shaped lid member 32 made of zirconia or the like are provided on the reference electrode 18 side of the airtight mass electrolyte layer 16 of the oxygen concentration detection cell 4, respectively. The hermetic mass electrolyte layer 16, the U-shaped spacer member 31, and the lid member 32 are laminated.
By being surrounded by the reference gas space 34, an airtight space, in other words, a reference gas space 34 isolated from the gas to be measured is formed. The reference electrode 18 is exposed in this reference gas space 34, and the reference gas space 34 is provided so as to extend toward one end in the longitudinal direction of the element, and is passed through an opening that opens at one end. It is designed to communicate with the atmosphere.

Since the reference electrode 18 is always exposed to a constant reference gas (atmosphere), it is possible to continuously measure, for example, a lean atmosphere where the oxygen partial pressure is lower than the oxygen partial pressure of the stoichiometric air-fuel ratio to a lean atmosphere where the oxygen partial pressure is high. , can be used as a wide area oxygen sensor.

Furthermore, the third major feature of such electrochemical elements is:
The heater layer 36 is provided on the outside of the lid member 32 forming the reference gas space 34 mentioned above, with an insulating layer 38 made of porous alumina or the like interposed therebetween. This heater layer 36 is provided because if the temperature of the gas to be measured such as exhaust gas to be measured is low and the solid electrolytes 8 and 16 are not maintained at a sufficiently high temperature, they will not be able to fully demonstrate their performance. , are provided to heat the solid electrolytes 8, 16 to a desired temperature.

This heater layer 36 is integrally bonded to the outside of the oxygen concentration detection cell 4 by sandwiching the heat generating part 40 and its lead part 42 between airtight ceramic layers 44 and 46 made of high-resistance zirconia or the like. The lead portion 42 is provided in such a manner that power can be supplied from an external power source through the lead portion 42.

Since the electrochemical device shown in this example adopts the above-mentioned basic form, it can advantageously enjoy the above-mentioned effects. The effect of following structural characteristics is also
They can be enjoyed together. In addition, 4 in Figure 4
8 is a high resistance layer for insulating the lead portion of the inner pump electrode 12 (measuring electrode 20) from the porous solid electrolyte layer 8, and is made of the same material as the high resistance ceramic layer 6.

Furthermore, in another embodiment of the electrochemical device according to the present invention shown in FIG.
Although it has a structure similar to that of the element shown in the figure, the reference electrode 18 of the oxygen concentration detection cell 4 is formed to have a large electrode surface, and the reference electrode 18 is formed with upper and lower airtight ceramic layers ( It is characterized by being airtightly surrounded by an airtight solid electrolyte layer 16 and an airtight lid member 32).

That is, by increasing the area of the electrode surface of the reference electrode 18 located on the heater layer 36 side, a slight leakage current from the heater layer 36 is absorbed, and the leakage current is transferred to the measurement electrode 20 side.
This is to prevent such leakage current from having an effect.

Note that an insulating layer 38 and the like is provided between the heater layer 36 and the oxygen concentration detection cell 4, but the leakage current from the heater layer 36 can be completely blocked by this. There is an inherent problem that such a leakage current flows to the oxygen concentration detection cell 4 side.

In addition, in the element of this embodiment, the reference electrode 18 is sandwiched between the airtight solid electrolyte layer 16 and the airtight lid member 32, and is thus surrounded by the airtight layer, so that the reference electrode 18 is surrounded by the airtight layer. The structure is isolated from the As is well known, a predetermined electromotive force is measured between the reference electrode 18 and the measurement electrode 20 in a state where the reference electrode 18 is maintained at a predetermined oxygen concentration potential formed by a pump action. That will happen.

Furthermore, in other embodiments of the present invention shown in FIGS. 7 and 8, the porous solid electrolyte layer 8 constituting the oxygen concentration detection cell 4 includes a plurality of solid electrolyte layers 3a having different porosity, A major feature is that it is composed of 3b. That is, by making the porous structure (porosity) of the porous solid electrolyte layer 8 different in the direction of gas diffusion, various effects can be obtained. By making the porosity of the electrolyte layer 8b larger than that of the solid electrolyte layer 8a on the gas to be measured side, in other words, by making it more porous, an atmosphere that can be brought into contact with the inner pump electrode 12 (measuring electrode 20) is created. This has the advantage that the rate of change in the output of the oxygen concentration detection cell relative to the claimed excess air ratio can be made more uniform, and the outer solid electrolyte layer 8a can be made more uniform than the inner solid electrolyte layer 8b. If the material is made more porous (higher porosity), clogging of the porous structure will be improved. Note that such a change in porosity can be performed stepwise as shown in the example, or it is also possible to use a porous layer in which the porosity changes continuously.

The solid electrolyte layer 9 is an airtight solid electrolyte layer in contact with the porous solid electrolyte layer 8, but as described above, it is separated from the part in contact with the inner pump electrode 12, and the porous solid electrolyte layer 8 It has no effect on the diffusion resistance.

Further, in this embodiment, as clearly shown in FIG. 8, the airtight ceramic layer 26 as the gas introduction direction control layer is a porous solid electrolyte composed of a plurality of solid electrolyte layers 8a, 3b, etc. It also surrounds the sides of the layer 8 and is hermetically joined to the airtight solid electrolyte layer 16 of the oxygen pump cell 2 via the airtight high resistance ceramic layer 6 made of high resistance zirconia. According to such a structure, the gas to be measured that diffuses through the porous solid electrolyte layer 8 (8a, 8b) flows through the notch hole 3 of the airtight ceramic layer 26.
Since the gas is introduced from the direction perpendicular to the electrode surface only through the electrode surface, it is possible to completely eliminate the diffusion of gas from the sides in the stacking direction.

Further, in this embodiment, the reference electrode 18 is isolated from the gas to be measured by the solid electrolyte layer 9 connected to the porous solid electrolyte layer 8 and the airtight high-resistance ceramic layer 6. The reference electrode 18 is connected in parallel with the potentiometer 52 and in series with the high resistance 56.
It supplies oxygen ions to maintain a high oxygen concentration potential.

In another embodiment of the present invention shown in FIG. 9, the solid electrolyte layer 16 constituting the oxygen concentration detection cell 4 has a cylindrical shape with a bottom, and a measuring electrode 20 and a high-resistance ceramic layer are provided on the outer surface of the solid electrolyte layer 16. 6, an inner pump electrode 12, a porous solid electrolyte layer 8, and an outer pump electrode 10, which constitute the oxygen pump cell 2, are laminated.

Although the other structures of this embodiment are slightly different in shape and arrangement, since they have the same functions as those of each of the above embodiments, they will be given the same numbers and detailed explanations will be omitted. That's it.

Although several embodiments of the present invention have been described above, the electrochemical device of the present invention should not be interpreted as being limited to such specific structures, but rather the gist of the present invention. The present invention may be implemented in forms with various modifications, modifications, improvements, etc. based on the knowledge of those skilled in the art without departing from the above, and the present invention includes such embodiments. It goes without saying.

The electrochemical element according to the present invention can be used not only as an example of a lean burn sensor but also as a rich burn sensor, as described above, and for measuring a gas to be measured such as exhaust gas that is combusted at a stoichiometric air-fuel ratio. It can be applied to oxygen sensors such as sensors, and it can also be applied to detectors or controllers of components involved in electrode reactions in fluids such as nitrogen, carbon dioxide, and hydrogen other than oxygen. It is.

[Brief explanation of drawings]

FIGS. 1 to 3 are perspective explanatory views showing the developed state of the basic structure of an oxygen concentration detection element, which is one of the electrochemical elements according to the present invention, and FIGS. FIG. 7 is a developed perspective explanatory view showing different specific examples of oxygen concentration detection elements adopting such basic structures, and FIGS. 1, 5, and 8 are IV in FIG. 4 and FIG. 7, respectively. - It is a schematic diagram showing the TV cross section and the ■-■ cross section, and it is a 9th
The figure is a sectional view showing a specific example of an oxygen concentration detection element employing such a basic structure. 2: Oxygen pump cell 4: Oxygen concentration detection cell 6: High resistance ceramic layer 8: Porous solid electrolyte layer 10: Outer pump electrode 12: Inner pump electrode 14: External power supply 16: Airtight solid electrolyte layer 18: Reference electrode 2
0: Measuring electrode 22: Measuring device 26: Airtight ceramic layer 30: Notch hole 31 Nice spacer member 32: Lid member 34: Reference gas space 36: Heater layer 38: Insulating layer Applicant Nippon Insulators Co., Ltd. Figure 1 Figure 2 Figure 3 Go to 25-' Figure 4 Figure 5 Figure 8 Figure 9 Figure 1n Hand 9 Neichi Seisho (self-prompted) Showa 5! ] July 10, 1, Indication of the case 1982 Patent example No. 116226 2, Name of the invention Electrochemical element and device 3, Person making the amendment Relationship to the case Patent applicant name (406) Nippon Insulator Co., Ltd. Company 4, Agent ■450 (1) Detailed description of the invention in the specification (2) Drawing 6, content of amendment (1) The “high-resistance ceramic layer” in the second line of page 19 of the specification was changed to “high-resistance ceramic layer” Corrected to "Resistance Ceramic Layer 6". (2) r L a 1-)CC on page 21, line 16
a x Y 03-” to [La+-ccazYOx-m
Correct to l. (3) “Insulating layer 38 consisting of
" is corrected to "Insulation consisting of N38." (4) In the same page, page 31, line 19, change “from output change rate” to “
Correct the output change rate to "more". (5) In the drawings, Figure 3 is corrected as shown in the attached sheet. Figure 3 Procedural amendments stamped on October 17, 1980 Manabu Shiga, Commissioner of the Patent Office, 1982 Patent Application No. 116226 2, Name of invention Electrochemical element and device 3, Person making the amendment Relationship to the case Patent applicant name (406) Nippon Insulator Co., Ltd. 4, agent fil Column for detailed explanation of the invention in the specification (2) Column 6 for a brief explanation of the drawings in the specification, Contents of amendment (1) ) Insert the following sentence between page 33, line 18 and line 19 of the specification on a new line. 10, FIG. 11, and FIG. 12 show a modification of the embodiment of the seventh leap. That is, in this modification, the embodiment of FIG. In contrast, the heater layer 36 is placed on the oxygen concentration detection cell 4 side, and the gas to be measured guided through the heater layer 36 and the notch and notch hole 30 provided in the oxygen concentration detection cell 4 has a porosity. Under a predetermined diffusion resistance regulated by a plurality of different solid electrolyte layers 8a and 8b, it is brought into contact with the measurement electrode 20 that is shared with the inner pump electrode 12 of the oxygen pump cell 2. The reference electrode 18 of the concentration detection cell 4 is also not brought into contact with the reference gas formed by electrolysis as in the embodiment shown in FIG.
The cutout portion of the letter-shaped spacer member 60 is brought into contact with the reference gas in the reference gas space 34 formed by covering the upper and lower solid electrolyte layers 16 and the lid member 32. Note that this reference gas space 34 is
It is connected to a reference gas supply source such as an external space through an opening at the end of the detection element, and a reference gas such as the atmosphere having a predetermined oxygen concentration is introduced thereinto. Further, here, the spacer member 60 and the lid member 32 are formed of a solid electrolyte, and together with the plurality of solid electrolyte layers 8a and 8b, constitute one solid electrolyte layer between the reference electrode 18 and the measurement electrode 20. Moreover, such an integral solid electrolyte layer and two electrodes constitute one electrochemical cell, that is, the oxygen concentration detection cell 4. (2) Page 35, line 11, 1... is a cross-sectional view. ", without a line break, [Figure 10 is a diagram corresponding to Figure 7 showing a modification of the embodiment in Figure 7;
The figure and FIG. 12 are Xa-Xa in FIG. 10, respectively.
It is a schematic diagram showing a cross section and an Xb-xb cross section. ” - Insert sentence. (3) Add Figures 10, 11M, and 12 as shown in the attached sheet. The above Figure 11 Figure 12 Procedural Amendment (December 8, 1981 Manabu Shiga, Commissioner of the Japan Patent Office, Rattan N1, Indication of the case, 1982 Patent Application No. 116226, 2, Name of the invention, Electricity) Chemical Elements and Devices 3, Relationship with the Amendment Person Case Name of Patent Applicant (406) Nippon Insulators Co., Ltd. 4, Agent (11 Claims column (2) of the specification) Details of the invention in the specification Explanation column 6, contents of amendment (1) The scope of claims is corrected as shown in the attached sheet. (2) “Outer pump electrode (first electrode), 10J” in page 13, lines 16-17 of the specification. [Corrected to "Outer pump electrode (second electrode) 1o". (3) "Inner pump electrode (
12" (second electrode) to "inner pump electrode (first electrode)
Corrected to ``12''. The appended claims (1) include: a porous first solid electrolyte layer having a predetermined gas diffusion resistance; and a porous first solid electrolyte layer provided on the surface of the second solid electrolyte layer. and a second electrode provided on the surface of the second solid electrolyte layer or the solid electrolyte layer connected thereto, separately from the first electrode; A third solid electrolyte layer consisting of a second solid electrolyte layer, a porous third electrode provided on the surface thereof, and a fourth electrode separated from the third electrode and provided on the surface of the second solid electrolyte layer. a second electrochemical cell; and at least a first solid electrolyte layer of the second electrochemical cell, a solid electrolyte layer connected thereto, and a second electrochemical cell interposed between the two cells; A laminated structure of high resistance ceramic layers electrically insulating a solid electrolyte layer of a chemical cell, the first electrode of the second electrochemical cell and the second electrochemical cell. An electrochemical device characterized in that the third electrodes of the electrodes are exposed to substantially the same atmosphere. (2) A patent claim in which the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are arranged at opposing positions with a porous ceramic layer interposed therebetween. The electrochemical device according to item 1. (3) Claim 1, wherein the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are constituted by one common electrode. electrochemical elements. (4) The second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell is surrounded by an airtight ceramic layer and isolated from the gas to be measured, and An electrochemical device according to any one of claims 1 to 3, which is exposed to a gas. (5) a space surrounded by the airtight ceramic layer is formed around the second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell; 5. The electrochemical device according to claim 4, wherein the space is communicated with the atmosphere. (6) A gas introduction direction control layer made of airtight ceramic is provided on the porous solid electrolyte layer and has pores facing the first electrode of the first electrochemical cell. 6. The electrochemical device according to claim 1, wherein the gas to be measured is guided to the second electrode from a direction perpendicular to the electrode surface through the hole. (7) According to any one of claims 1 to 6, wherein the porous solid electrolyte layer of the first electrochemical cell is composed of a plurality of solid electrolyte layers having different porosity. The electrochemical device described. (8) A porous first solid electrolyte layer having a predetermined gas diffusion resistance, and porous first and second electrodes provided opposite to each other on both sides of the second solid electrolyte layer. A first electrochemical cell consisting of a second solid electrolyte layer, a porous third electrode provided on the surface of the second solid electrolyte layer, and a second solid electrolyte layer surface separated from the third electrode. a second electrochemical cell comprising a fourth electrode provided on the second electrochemical cell; a laminated structure of high-resistance ceramic layers that electrically insulate the solid electrolyte layer and the solid electrolyte layer of the second electrochemical cell; a third electrode of said second electrochemical cell constitutes an electrochemical element exposed to substantially the same atmosphere; Control the atmosphere near the second electrode by passing a predetermined current between them, and detect the controlled atmosphere as a potential difference between the third and fourth electrodes of the second electrochemical cell. An electrochemical device characterized by: (9) A patent claim in which the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are arranged at opposing positions with a porous ceramic layer interposed therebetween. The electrochemical device according to item 8. α0) The first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are constituted by one common electrode. Electrochemical device. (11) Claim 8, wherein the fourth electrode of the second electrochemical cell is surrounded by an airtight ceramic layer, isolated from the gas to be measured, and exposed to a predetermined reference gas. The electrochemical device according to any one of items 1 to 10. 12) A space surrounded by the airtight ceramic layer is formed around a fourth electrode of the second electrochemical cell, and the space is communicated with the atmosphere. 12. Electrochemical device according to item 11. (+3) A porous first solid electrolyte layer having a predetermined gas diffusion resistance, a porous first electrode provided on the surface of the negative solid electrolyte layer, and a porous first electrode provided on the surface of the negative solid electrolyte layer. a first electrochemical cell comprising a second electrode provided on the surface of the solid electrolyte layer or a solid electrolyte layer connected thereto, separately from the first electrode; a second solid electrolyte layer; a second electrochemical cell consisting of porous third and fourth electrodes provided oppositely on both sides; and intervening between these two cells, at least It consists of a laminated structure of high-resistance ceramic layers that electrically insulate the first solid electrolyte layer, the solid electrolyte layer connected thereto, and the solid electrolyte layer of the second electrochemical cell, and a first electrode of the electrochemical cell and a third electrode of the second electrochemical cell constitute an electrochemical element exposed to substantially the same atmosphere; By passing a predetermined current between the third and fourth electrodes of the cell, the atmosphere near the third electrode is controlled, and the controlled atmosphere is applied to the first and fourth electrodes of the first electrochemical cell. An electrochemical device characterized in that detection is performed as a potential difference between second electrodes. θ4) The first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are arranged at opposite positions with a porous ceramic layer interposed therebetween. An electrochemical device according to scope 13. (15) Claim 13, wherein the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are constituted by one common electrode. electrochemical device. (16) The second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell is surrounded by an airtight ceramic layer and isolated from the gas to be measured, and 16. The electrochemical device according to claim 13, wherein the electrochemical device is exposed to a gas. 07) A space surrounded by the airtight ceramic layer is formed around the second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell, and 17. The electrochemical device of claim 16, wherein the electrochemical device is in communication with the atmosphere.

Claims (17)

[Claims] (1) A porous first solid electrolyte layer having a predetermined gas diffusion resistance, a porous first electrode provided on the surface of the second solid electrolyte layer, and a porous first solid electrolyte layer having a predetermined gas diffusion resistance. a first electrochemical cell comprising a second electrode provided on the surface of the solid electrolyte layer or a solid electrolyte layer connected thereto, separately from the first electrode; a second solid electrolyte layer; a second electrochemical cell comprising a porous third electrode provided on the surface and a fourth electrode provided on the second solid electrolyte layer surface separated from the third electrode; and , interposed between the two cells, at least the first solid electrolyte layer of the second electrochemical cell and the solid electrolyte layer connected thereto, and the solid electrolyte layer of the second electrochemical cell. A laminated structure of high-resistance ceramic layers electrically insulating the first electrochemical cell, and the first electrode of the second electrochemical cell and the third electrode of the second electrochemical cell are substantially An electrochemical element characterized in that it is exposed to the same atmosphere. (2) A patent claim in which the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are arranged at opposing positions with a porous ceramic layer interposed therebetween. The electrochemical device according to item 1. (3) Claim 1, wherein the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are constituted by one common electrode. electrochemical elements. (4) The second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell is surrounded by an airtight ceramic layer and isolated from the gas to be measured, and An electrochemical device according to any one of claims 1 to 3, which is exposed to a gas. (5) a space surrounded by the airtight ceramic layer is formed around the second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell; 5. The electrochemical device according to claim 4, wherein the space is communicated with the atmosphere. (6) A gas introduction direction control layer made of airtight ceramic is provided on the porous solid electrolyte layer and has pores facing the first electrode of the first electrochemical cell. 6. The electrochemical device according to claim 1, wherein the gas to be measured is guided to the second electrode from a direction perpendicular to the electrode surface through the hole. (7) According to any one of claims 1 to 6, wherein the porous solid electrolyte layer of the first electrochemical cell is composed of a plurality of solid electrolyte layers having different porosity. The electrochemical device described. (8) A porous first solid electrolyte layer having a predetermined gas diffusion resistance, and porous first and second electrodes provided opposite to both sides of the second solid electrolyte layer. A first electrochemical cell consisting of a second solid electrolyte layer, a porous third electrode provided on the surface of the second solid electrolyte layer, and a second solid electrolyte layer surface separated from the third electrode. a second electrochemical cell comprising a fourth electrode provided on the second electrochemical cell; and interposed between the two cells, at least the first solid electrolyte layer of the second electrochemical cell and connected thereto; a laminated structure of high-resistance ceramic layers that electrically insulate the solid electrolyte layer and the solid electrolyte layer of the second electrochemical cell; a third electrode of said second electrochemical cell constitutes an electrochemical element exposed to substantially the same atmosphere; Control the atmosphere near the second electrode by passing a predetermined current between them, and detect the controlled atmosphere as a potential difference between the third and fourth electrodes of the second electrochemical cell. An electrochemical device characterized by: (9) A patent claim in which the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are arranged at opposing positions with a porous ceramic layer interposed therebetween. The electrochemical device according to item 8. (10) Claim 8, wherein the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are constituted by one common electrode. electrochemical device. (11) The second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell is surrounded by an airtight ceramic layer and isolated from the gas to be measured, and An electrochemical device according to any one of claims 8 to 10, which is exposed to a gas. (12) a space surrounded by the airtight ceramic layer is formed around the second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell; 12. The electrochemical device according to claim 11, wherein the space is communicated with the atmosphere. (13) a porous first solid electrolyte layer having a predetermined gas diffusion resistance; a porous first electrode provided on the surface of the second solid electrolyte layer; a first electrochemical cell comprising a second electrode provided on the surface of the solid electrolyte layer or a solid electrolyte layer connected thereto, separately from the first electrode; a second solid electrolyte layer; a second electrochemical cell consisting of porous third and fourth electrodes provided oppositely on both sides; and intervening between these two cells, at least It is made of a laminated structure of high-resistance ceramic layers that electrically insulate one solid electrolyte layer, a solid electrolyte layer connected thereto, and the solid electrolyte layer of the second electrochemical cell; a first electrode of the electrochemical cell and a third electrode of the second electrochemical cell constitute an electrochemical element that is exposed to substantially the same atmosphere; By passing a predetermined current between the third and fourth electrodes of the first electrochemical cell, the atmosphere near the third electrode is controlled, and the controlled atmosphere is transferred to the first electrode of the first electrochemical cell. and a second electrode. (14) A patent claim in which the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are arranged at positions facing each other with a porous ceramic layer interposed therebetween. 14. The electrochemical device according to item 13. (15) Claim 13, wherein the first electrode of the first electrochemical cell and the third electrode of the second electrochemical cell are constituted by one common electrode. electrochemical device. (16) The second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell is surrounded by an airtight ceramic layer and isolated from the gas to be measured, and 16. The electrochemical device according to claim 13, wherein the electrochemical device is exposed to a gas. (17) A space surrounded by the airtight ceramic layer is formed around the second electrode of the first electrochemical cell or the fourth electrode of the second electrochemical cell, and 17. The electrochemical device according to claim 16, wherein the space is communicated with the atmosphere.