JP2013217743A - Gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas sensor capable of detecting gas and measuring a gas concentration appropriately in a simple construction, a method of manufacturing the gas sensor, and a coin battery type gas sensor using the gas sensor.SOLUTION: In a gas sensor, a sensor element 30 where a pair of electrodes are laminated through a solid electrolyte film is held by a pair of electrode covers through a pair of gas-permeable conductors 37, and the sensor element 30, the gas-permeable conductors 37, and the electrode covers include at least one open hole 34 communicating with them in a vertical direction.

Description

The present invention relates to a gas sensor capable of suitably detecting a gas and measuring a gas concentration with a simple structure, a method for manufacturing the gas sensor, and a coin battery type gas sensor using the gas sensor.

Conventionally, an electromotive force measurement type gas sensor or the like is known as a gas sensor for detecting a detection target gas. Such gas sensors are widely used not only in general households but also in various fields such as automobiles, semiconductors, food, distribution, medical care, and manufacturing.

In recent years, fuel cells have attracted attention as energy sources for electric vehicles. A fuel cell is a chemical cell that can continuously extract electric power by continuously supplying a fuel such as hydrogen and an oxidant such as oxygen.
It is known that hydrogen gas, which is an energy source for fuel cells, easily explodes due to ignition when the concentration in the air reaches a range of 4 to 75%. Therefore, when hydrogen is used, there is an increasing demand for a hydrogen gas sensor that can be accurately detected by a simple method at a concentration of 4% or less of the lower explosion limit concentration of hydrogen gas.

As such a hydrogen gas sensor, an electromotive force measurement method using a proton conductor is conventionally known. For example, Patent Document 1 discloses a method for measuring the amount of permeated hydrogen gas using a solid polymer electrolyte membrane with carbon cross electrodes attached to both sides.

Patent Document 2 discloses a hydrogen gas having both side support members positioned opposite to each other and a proton conductive layer sandwiched between the two, and introducing hydrogen gas from one side and flowing out hydrogen gas from the other side. A gas sensor is disclosed.

JP 2002-289243 A JP 2005-338051 A

However, the hydrogen gas sensors disclosed in Patent Documents 1 and 2 effectively output because a positional deviation occurs between the gas permeable conductor (carbon paper) and other supporting members that are in direct contact with the proton conductor. There is a problem that the counter contact area that can be taken out (hereinafter referred to as effective contact area) becomes smaller, and the signal becomes smaller than the actual output per support member area. In addition, when a plurality of products are produced, the electric signal values between the individual sensors are not the same, which causes variations in measured values.
On the other hand, in JP-A-2001-215214, JP-A-2003-75403, and the like, even if a positional deviation occurs, a deviation occurs in output for the purpose of securing an effective contact area necessary for product design. The proton conducting layer is designed to be larger than the electrode so that there is no such problem. Similarly, for the purpose of securing an effective contact area necessary for product design, as shown in FIG. 7, by using an electrolyte membrane and carbon paper having an excessively large area for design, the horizontal direction of each component element is used. Even if there is a deviation, it is possible to ensure an effective contact area. However, this method can solve the problem of misalignment due to pinching, but the materials are wasted in both the carbon paper and the electrolyte membrane, and it cannot be said that each member is effectively used.

The present invention solves the above problems, and can prevent a decrease in output due to a decrease in effective contact area due to a positional shift between the proton conductor and the support member with a simple structure, (2) An object of the present invention is to provide a gas sensor that can be easily manufactured at the time of assembling the sensor, and (3) can detect a gas and measure a gas concentration without variation even when a plurality of sensors are produced. .

In the present invention, a sensor element in which a pair of electrodes are stacked via a solid electrolyte membrane is sandwiched between a pair of electrode covers via a pair of gas permeable conductors. The electrode cover is a gas sensor having at least one communicating through hole in the vertical direction.
The present invention is described in detail below.

In the gas sensor in which a pair of gas permeable conductors and an electrode cover are stacked on the sensor element, the inventor forms at least one through-hole in the vertical direction so that the electrode and the support member have a simple structure. It is possible to prevent a decrease in output due to a positional deviation with respect to the (electrode cover), facilitating manufacture, and even when producing a plurality, it is possible to detect a gas and measure a gas concentration without causing variations. I found out that
Further, the present inventors have found that the waste of materials can be minimized in both the gas permeable conductor and the solid electrolyte membrane, and the present invention has been completed.

In the gas sensor of the present invention, the sensor element, the gas permeable conductor, and the electrode cover have at least one through hole in the vertical direction.
By having such a through-hole, for example, a positioning pin or the like is inserted into the through-hole of a laminate (sensor element) in which a pair of electrodes are laminated via the solid electrolyte membrane, and the gas-permeable conductor and By installing the electrode cover, it is possible to prevent a decrease in output due to a positional shift between the sensor element, the gas permeable conductor and the electrode cover, and it becomes easy to manufacture at the time of assembling the sensor. Even in this case, it is possible to provide a gas sensor capable of detecting a gas and measuring a gas concentration without causing variations.
Moreover, the gas sensor of the present invention has a through hole, so that it is possible to detect a gas and measure a gas concentration without obstructing the air flow even for a gas having an air flow.
Furthermore, it is possible to pass a gas pipe through the through hole, and it is also possible to grasp from where the gas leaks by passing a plurality of sensors through the gas pipe.
In addition, by having a through hole, it can be easily installed anywhere with a fixing pin.

FIG. 1 shows an example of a gas sensor of the present invention.
The gas sensor 30 has a configuration in which a sensor element composed of a first electrode 31, a second electrode 32, and a solid electrolyte membrane 33 is sandwiched between stainless steel electrode plates 36 via a gas permeable conductor 37. Also, one through hole 34 is formed in the vertical direction near the center of the gas sensor 30.
The stainless steel electrode plate 36 is also electrically connected to the first electrode 31 and the second electrode 32 via the gas permeable conductor 37, and thus has a function as an output output electrode. By connecting 39, the function as a gas sensor can be exhibited.
In the present invention, by using a gas sensor having a through hole, the sensor element including the first electrode 31, the second electrode 32, and the solid electrolyte membrane 33, and the stainless steel electrode plate 36 and the gas permeable conductor 37 are used. In this case, it is possible to detect the gas and measure the gas concentration without any variation even when producing multiple products, while preventing the output from decreasing and minimizing the waste of materials. A gas sensor can be provided.
Further, by adopting such a configuration, it is possible to perform accurate hydrogen gas measurement while protecting the first electrode 31, the second electrode 32, and the solid electrolyte membrane 33 that are important for hydrogen gas measurement.
As an application of the gas sensor 30, a configuration in which the gas sensor 30 is installed on a printed board may be adopted.

The shape of the sensor element in the present invention is not particularly limited, and may be a circular shape, a polygonal shape, or the like. In particular, when the shape of the sensor element is a rectangle such as a rectangle or a square, since the yield at the time of punching the sensor element at the time of manufacture is high, the material can be used effectively.

In the present invention, the cross-sectional shape of the through hole is not particularly limited, but the number of through holes and the optimum cross-sectional shape can be determined by the shape of the sensor element. For example, when the shape of the sensor element is circular, positioning can be performed by providing a plurality of through holes, but positioning can be determined if there is one through hole at the center. The cross-sectional shape of the through hole at this time may be circular or polygonal.
In addition, when the sensor element has a polygonal shape, for example, when the sensor element has a square shape, when positioning is performed by providing a single through-hole, a polygonal cross-sectional through-hole is provided at the center. In addition, when the through hole is to have a circular cross-sectional shape, at least two through holes are required.
Thus, the number of through holes and the cross-sectional shape of the through holes can be set according to the shape of the sensor element.

The ratio of the through area to the electrode cover area of the through hole is not particularly limited. However, if the through area is too large, the amount of waste material associated with the penetration increases and the output that can be taken out decreases. Moreover, when the ratio of a penetration area is too small, handling will become difficult in a manufacturing process. Therefore, it is preferable that the through area of the through hole occupies 0.5 to 15% with respect to the electrode cover area. By making it within the above-mentioned range, it is possible to prevent a decrease in output while preventing waste of material due to penetration, and it is easy to handle during the manufacturing process, and furthermore, variations in manufacturing a plurality can be reduced. Furthermore, in order to prevent waste of materials and a decrease in output, it is more preferable that the area of the through hole occupies 1 to 10% with respect to the electrode cover area.
Moreover, although the said through-hole should just be formed at least one, 1-5 pieces are preferable.

The formation position of the through hole is not particularly limited, but it is preferably formed at the center of the gas sensor for ease of positioning. Further, when a plurality of through holes are formed, they may be formed at the peripheral edge.

An example of a sensor element constituting the gas sensor of the present invention is shown in FIG.
The sensor element 10 includes a first electrode 11, a second electrode 12, and a solid electrolyte film 13, and the first electrode 11 and the second electrode 12 are stacked via the solid electrolyte film 13. . Also, one through hole 14 is formed in the vertical direction near the center of the sensor element 10.

The principle when the sensor element 10 is used for a hydrogen gas sensor will be described.
In the sensor element 10, the first electrode 11 and the second electrode 12 contain a metal having a catalytic action capable of dissociating hydrogen into protons. Thus, when hydrogen gas is present in the vicinity of the surfaces of the first electrode 11 and the second electrode 12, hydrogen is dissociated into protons and electrons as shown in the following formula (1).
H ₂ → 2H ⁺ + 2e ⁻ (1)
Protons generated by dissociation diffuse in the first electrode 11 and the second electrode 12 and reach the solid electrolyte membrane 13. At the same time, a reaction in which protons disappear due to oxygen present in the atmosphere near the surfaces of the first electrode 11 and the second electrode 12 as shown in the following formula (2).
2H ⁺ + 1 / 2O ₂ + 2e ⁻ → H ₂ O (2)
Therefore, in the sensor element 10, the reaction of the above formulas (1) and (2) occurs in the first electrode 11 and the second electrode 12 by electrically connecting the first electrode 11 and the second electrode 12. After hydrogen molecules contained in the atmosphere reach the electrode surface, the concentration of hydrogen molecules or protons decreases as they diffuse from the electrode surface to the inside.
Since such a reaction occurs continuously, a current corresponding to the hydrogen concentration flows in the external circuit, and thus the hydrogen concentration can be measured by measuring the current.
The proton that has moved to the second electrode 12 side is reduced by electrons through an external circuit by the reaction (2).

As the electrodes (first electrode and second electrode), noble metals, noble metal compounds, noble metal alloys, heavy metals such as molybdenum, tungsten, and titanium, heavy metal compounds, heavy metal alloys, and the like can be used.
In particular, when the gas sensor of the present invention is used as a hydrogen gas sensor, it preferably contains a metal having a catalytic action capable of dissociating hydrogen into protons, and may be carbon carrying a metal having a catalytic action capable of dissociating hydrogen into protons. . As a result, the reactions of the above formulas (1) and (2) can be generated in the first electrode and the second electrode.
As the metal having a catalytic action capable of dissociating hydrogen into protons, for example, a platinum group metal such as platinum, palladium, rhodium, ruthenium, iridium, osmium is preferably used.
Moreover, it is preferable to use what consists of a platinum group metal as a 1st electrode, and use what consists of carbon which carry | supported the platinum group metal as a 2nd electrode. As a result, even if the amount of catalytic metal is small, the area where the second electrode is in contact with oxygen and hydrogen in the atmosphere increases, so that the reaction (2) is further promoted and the proton concentration in the solid electrolyte membrane is reduced. Can be lowered.

The film thickness of the first electrode and the second electrode is preferably 1 to 200 nm. When the film thickness of the electrode is less than 1 nm, the electric resistance increases and it becomes difficult to take out the current. When the film thickness exceeds 200 nm, the number of protons that reach the solid electrolyte membrane decreases, so the current corresponding to the hydrogen concentration decreases and sensitivity increases. Lower. More preferably, it is 5 to 80 nm.

In the present invention, the thickness of the second electrode is preferably larger than the thickness of the first electrode, and the difference between the thickness of the second electrode and the thickness of the first electrode is preferably 10 to 200 nm.
If the difference in film thickness is less than 10 nm, the proton concentration difference becomes small and the current corresponding to the hydrogen concentration becomes small, so the sensitivity may be low. If it exceeds 200 nm, the response speed decreases and the solid electrolyte membrane Curling or the like may occur.
More preferably, it is 30-80 nm.

When the first electrode and the second electrode have different film thicknesses as described above, the film thickness of the first electrode is preferably 1 to 25 nm. If the thickness of the first electrode is less than 1 nm, the electrical resistance may increase and current may be difficult to extract. If the thickness exceeds 25 nm, the number of protons that reach the solid electrolyte membrane decreases, so the current according to the hydrogen concentration. May be reduced and the sensitivity may be lowered. More preferably, it is 5-10 nm.

When the first electrode and the second electrode have different film thicknesses as described above, the film thickness of the second electrode is preferably 30 to 200 nm.
If the film thickness of the second electrode is less than 30 nm, the amount of protons that reach the solid electrolyte membrane increases, so that the current value corresponding to the hydrogen concentration decreases and the sensitivity may decrease. Decrease in speed or curling of the solid electrolyte membrane may occur.
More preferably, it is 40-100 nm.

Examples of the solid electrolyte membrane include perfluorinated polymers having high proton conductivity such as perfluorosulfonic acid and perfluorocarboxylic acid, and partially sulfonated styrene-olefins such as Poly (styrene-ran-ethylene) and sulfonated. It is preferable to employ a solid polymer electrolyte membrane made of copolymer. Specifically, Nafion (manufactured by DuPont, registered trademark: NAFION), Aciplex (manufactured by Asahi Kasei Corporation, registered trademark: ACIPLEX) and the like can be suitably used. Further, conductive particles may be dispersed in the solid electrolyte membrane.

The thickness of the solid electrolyte membrane is preferably 5 to 200 μm.
If the thickness of the solid electrolyte membrane is less than 5 μm, the mechanical strength may be low and it may be easily broken, or a short circuit may occur between the first electrode and the second electrode due to pinholes. When it exceeds 200 μm, the response speed may be lowered.
More preferably, it is 10-100 micrometers.

As the gas permeable conductor, carbon paper, foam metal or the like can be used.
The carbon paper is a porous body made of carbon fiber and carbon, and is also used for a gas diffusion layer of a fuel cell, etc., and therefore has excellent gas permeability and conductivity. Foam metal is used for battery electrode materials, filters, and the like, and those having a porosity of 90% or more have particularly good gas permeability, and also have low resistance because they are metal.

The electrode cover is not particularly limited as long as it is a member having conductivity and capable of fixing and protecting the sensor element and the gas permeable conductor, but a stainless steel member is preferably used. .

As a method for manufacturing a gas sensor according to the present invention, a sensor element in which a pair of electrodes are stacked via a solid electrolyte membrane, a pair of gas permeable conductors, and at least one through hole in the vertical direction of the pair of electrode covers are provided. A step of forming, and a step of sandwiching the sensor element with the electrode cover through the gas permeable conductor while inserting a positioning pin into the through hole of the sensor element, the gas permeable conductor and the electrode cover, and A method having a step of fixing the electrode cover can be used.
By using such a method, it is possible not only to prevent displacement between the sensor element, the gas permeable conductor, and the electrode cover, but also to simplify the manufacturing process.

Examples of the step of forming at least one through hole in the vertical direction of the sensor element, the pair of gas permeable conductors, and the pair of electrode covers in which the pair of electrodes are stacked via the solid electrolyte membrane include, for example, A method of individually forming through holes in the sensor element, the gas permeable conductor, and the electrode cover, a method of simultaneously forming through holes, or the like can be used.
Examples of the method for forming the through hole include a Thomson blade, an etching blade, an engraving blade, a laser, and punching with a mold.

As a method for producing the sensor element, for example, a step of forming a first electrode and a second electrode having a predetermined thickness on both sides of the solid electrolyte membrane, and a step of cutting the obtained laminated body into a predetermined size And a method of performing a step of forming a through hole. In particular, by simultaneously performing the step of cutting to a predetermined size and the step of forming the through-hole, the number of manufacturing steps does not increase and the manufacturing steps can be simplified.

Examples of the method for forming the first electrode and the second electrode include methods capable of forming a thin film such as sputtering, vapor deposition, and laser ablation.

Next, in the manufacturing method of the present invention, the sensor element is sandwiched between the sensor element, the gas permeable conductor, and the electrode cover through the gas permeable conductor while inserting a positioning pin into the through hole of the electrode cover. I do. By performing such a process, the sensor element, the gas permeable conductor, and the electrode cover are not sandwiched when they are combined, and handling properties can be improved.

FIG. 3 shows an example of a method of clamping a sensor element with an electrode cover through a gas permeable conductor while inserting a positioning pin in the manufacturing method of the present invention.
A through hole is formed in the vertical direction near the center of the gas sensor including the first electrode 41, the second electrode 42, and the solid electrolyte membrane 43.
When the gas permeable conductor 47 and the stainless steel electrode plate 46 are installed above and below the gas sensor, a positioning pin 48 is inserted into the through hole of the gas sensor in advance, and then the pair of gas permeable conductor 47 and the stainless steel electrode. A plate 46 is installed.
As a result, a plurality of gas sensors are produced without any displacement between the gas sensor including the first electrode 41, the second electrode 42, and the solid electrolyte membrane 43, and the stainless steel electrode plate 46 and the gas permeable conductor 47. Even in this case, it is possible to provide a gas sensor capable of detecting a gas and measuring a gas concentration without causing variations.

Next, in the manufacturing method of the present invention, a step of fixing the electrode cover is performed. The fixing method is not particularly limited, and a method such as screwing can be used.

A coin battery type gas sensor using the gas sensor of the present invention is also one aspect of the present invention.
An example in which the present invention is applied to a coin battery type gas sensor is shown in FIG.
The hydrogen gas sensor 50 is an example when the present invention is used as a coin battery type hydrogen gas sensor.
The hydrogen gas sensor 50 has a configuration in which a laminated body including a first electrode 51, a second electrode 52, and a solid electrolyte membrane 53 is sandwiched between a pair of stainless steel electrode covers 56. Further, the stainless steel electrode cover 56 is also electrically connected to the first electrode 51 and the second electrode 52 through the gas permeable conductor 57, thereby also having a function as an electrode. Further, the pair of stainless steel electrode covers 56 are electrically insulated via insulating spacers 58. In this way, the electrode is clamped and fixed, so that the sensor becomes strong, and there is no loosening of screws or disconnection of the wiring, so the hydrogen gas sensor itself can be easily carried, and the detector replacement type It can also be used for a hydrogen gas sensor device.

As an electrode used for the coin battery type gas sensor, an electrode press-molded to a standard size such as CR2032 or CR2016 can be used, but when used for a hydrogen sensor, a vent hole is provided for gas permeation. As the insulating spacer, a molded one that matches the shape of the battery case made of polypropylene or the like is used.

The gas sensor of the present invention can be used to detect hydrogen gas, carbon monoxide gas, carbon dioxide gas, methane gas, nitrogen monoxide, nitrogen dioxide gas, sulfur dioxide gas, and the like and to measure the gas concentration. Among these, it is preferable to use for detection of hydrogen gas and measurement of gas concentration.

According to the present invention, in a gas sensor having a configuration in which a sensor element, a gas permeable conductor, and an electrode cover are stacked, the displacement between each member can be eliminated with a simple structure, and the contact area caused by the displacement is reduced. It is possible to eliminate the decrease in output signal.
In addition, by using the manufacturing method of the present invention, it is possible to easily assemble a gas sensor, reduce variations among manufactured gas sensors, and provide a gas sensor capable of stable gas detection and gas concentration measurement. can do.

It is a schematic diagram which shows an example of the gas sensor of this invention. It is a schematic diagram which shows an example of the sensor element which comprises the gas sensor of this invention. It is a schematic diagram which shows an example of the positioning method using the gas sensor of this invention. It is a schematic diagram which shows an example of the gas sensor of this invention. 6 is a schematic diagram illustrating a manufacturing process of a gas sensor of Example 2. FIG. 6 is a schematic diagram illustrating a manufacturing process of the gas sensor of Example 3. FIG. It is a schematic diagram at the time of applying the technology of the conventional gas sensor.

Examples of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1
A perfluorosulfonic acid polymer membrane (manufactured by DuPont) having a thickness of 50 μm was used as the solid electrolyte. A platinum film having a thickness of 10 nm was laminated as a first electrode on one surface of the perfluorosulfonic acid polymer film by sputtering (input power of 0.5 KW in Ar gas 0.4 Pa). Further, a platinum film having a thickness of 70 nm was stacked as the second electrode on the other side of the surface on which the first electrode was stacked by a sputtering method.
Thereafter, the etching blade was used to punch a circular shape having a diameter of 10.5 mm, and at the same time, a through hole having a diameter of 3 mm was punched in the center of the circular shape.
A pair of carbon paper having a through hole with a diameter of 3 mm (made by Toray Industries, Inc., circular shape with a diameter of 10.0 mm, thickness of about 0.2 mm) is arranged so as to sandwich the obtained laminate, and the diameter is further measured from both sides. The sample was sandwiched between a pair of stainless plates (circular shape with a diameter of 20 mm) having 3 mm through holes. At this time, as shown in FIG. 3, a cylindrical positioning pin having a diameter of 3 mm is inserted into the laminated body, the carbon paper, and the through hole of the stainless steel plate for alignment, and then the stainless steel plates are joined with resin screws. The sensor as shown in FIG. 1 was obtained by fastening and fixing the whole.
When the obtained sensor was placed in a glass tube and the output current value in air with a hydrogen concentration of 1% was measured, the current value was 40.8 μA (effective contact area of 87.92 mm ² according to the calculated value).
In addition, a total of 10 gas sensors were produced by the same method as in Example 1. For these gas sensors, when the output current value in the air with a hydrogen concentration of 1% was measured, the current values were 40.8 μA, 39.72 μA, 39.91 μA, 40.5 μA, 40.1 μA, 39.88 μA, 39. It was 90 μA, 40.8 μA, 40.4 μA, 40.0 μA, and the difference between the maximum value and the minimum value was 1.08 μA, so it was confirmed that the variation in the output current value was small.

(Example 2)
A perfluorosulfonic acid polymer membrane (manufactured by DuPont) having a thickness of 50 μm was used as the solid electrolyte. A platinum film having a thickness of 10 nm was laminated as a first electrode on one surface of the perfluorosulfonic acid polymer film by sputtering (input power of 0.5 KW in Ar gas 0.4 Pa). Further, a platinum film having a thickness of 70 nm was stacked as the second electrode on the other side of the surface on which the first electrode was stacked by a sputtering method.
Thereafter, punching into a circular shape with a diameter of 10.5 mm was performed using an etching blade, and at the same time, two through-holes with a diameter of 1 mm were simultaneously punched at a position 3.5 mm away from the edge on the circular diameter.
A pair of carbon paper having two through-holes with a diameter of 1 mm at a position 2.5 mm away from the edge on the diameter of the circle so as to sandwich the obtained laminate (Toray, Inc., circle with a diameter of 10.0 mm A pair having a through-hole with a diameter of 3 mm at the center and two through-holes with a diameter of 8 mm at a position 8 mm away from the edge on the circular diameter. Of stainless steel plates (circular shape with a diameter of 20 mm). At this time, as shown in FIG. 5, two cylindrical positioning pins having a diameter of 1 mm are inserted through the through holes of the laminate, the carbon paper, and the stainless plate, and then the stainless plates are made of resin. The sensor was obtained by fastening with screws and fixing the whole. FIG. 5A is a side view showing a manufacturing process in Example 2, and FIG. 5B is a top view. In Example 2, the gas sensor is manufactured by inserting the two positioning pins 68 into the through hole.
When the output current value of the obtained sensor in air with a hydrogen concentration of 1% was measured, the current value was 37.8 μA.

(Example 3)
As the solid electrolyte, a perfluorosulfonic acid polymer membrane (manufactured by DuPont) having a length of 50 mm × width of 50 mm × thickness of 50 μm was used. A platinum film having a thickness of 10 nm was laminated as a first electrode on one surface of the perfluorosulfonic acid polymer film by sputtering (input power of 0.5 KW in Ar gas 0.4 Pa). Further, a platinum film having a thickness of 70 nm was stacked as the second electrode on the other side of the surface on which the first electrode was stacked by a sputtering method.
Thereafter, a 10 mm × 10 mm square was punched out using an etching blade, and at the same time, a 2 mm × 2 mm square through hole was punched out in the center thereof.
A pair of carbon papers (made by Toray Industries Inc., 9 mm × 9 mm square, about 0.2 mm thick) having a 2 mm × 2 mm square through-hole at the center are arranged so as to sandwich the obtained laminate. And sandwiched between a pair of stainless steel plates (20 mm × 20 mm square shape) having a 2 mm × 2 mm square through hole in the center. At this time, as shown in FIG. 6, with a positioning pin having a square section of 1.8 mm × 1.8 mm, the laminated body, the carbon paper, and the stainless steel plate are inserted and aligned, and then the stainless steel plates are aligned with each other. Was fastened with a resin screw and the whole was fixed to obtain a sensor. FIG. 6A is a side view showing the manufacturing process in Example 3, and FIG. 6B is a top view. In Example 3, the gas sensor is manufactured by inserting the positioning pin 78 having a square cross section into the through hole.
When the output current value of the obtained sensor in air with a hydrogen concentration of 1% was measured, the current value was 43.4 μA.

(Comparative Example 1)
A perfluorosulfonic acid polymer membrane (manufactured by DuPont) having a thickness of 50 μm was used as the solid electrolyte. A platinum film having a thickness of 10 nm was laminated as a first electrode on one surface of the perfluorosulfonic acid polymer film by sputtering (input power of 0.5 KW in Ar gas 0.4 Pa). Further, a platinum film having a thickness of 70 nm was stacked as the second electrode on the other side of the surface on which the first electrode was stacked by sputtering. Thereafter, it was punched into a circular shape having a diameter of 13 mm.
A pair of carbon papers (manufactured by Toray Industries, Inc., circular shape with a diameter of 11 mm, thickness of about 0.2 mm) are arranged so as to sandwich the obtained laminate, and a pair of stainless steel plates (circular shape with a diameter of 20 mm) from both sides. ), And was fastened with resin screws, and the whole was fixed to obtain a sensor.
When the obtained sensor was placed in a glass tube and the output current value in air having a hydrogen concentration of 1% was measured, the current value was 25 μA.
Here, the reason why the current value (25 μA) in Comparative Example 1 was lower than that in the Example was considered to be due to the deviation between the gas-permeable conductor (carbon paper) and the support member (stainless plate).
In addition, a total of 10 gas sensors were produced by the same method as in Comparative Example 1. For these gas sensors, when the output current value in the air with a hydrogen concentration of 1% was measured, the current values were 30.2 μA, 27.8 μA, 25.0 μA, 33.1 μA, 34.5 μA, 35.8 μA, 26. 3 μA, 29.9 μA, 32.2 μA, and 32.9 μA, and the difference between the maximum value and the minimum value was 10.8 μA, so it was confirmed that the variation in the output current value was large.

According to the present invention, a gas sensor capable of preventing displacement between members with a simple structure and capable of detecting a gas and measuring a gas concentration without variation even when a plurality of members are produced. The gas sensor manufacturing method and the coin battery type gas sensor using the gas sensor can be provided.

Claims (6)

A sensor element in which a pair of electrodes are stacked via a solid electrolyte membrane is sandwiched between a pair of electrode covers via a pair of gas permeable conductors,
The sensor element, the gas permeable conductor, and the electrode cover have at least one through hole that communicates in the vertical direction. The gas sensor according to claim 1, wherein the through hole is formed in a central portion. 3. The gas sensor according to claim 1, wherein the gas sensor is used for detecting hydrogen gas, and the electrode is made of a metal having a catalytic action capable of dissociating hydrogen into protons. The gas sensor according to claim 3, wherein the metal having a catalytic action capable of dissociating hydrogen into protons is platinum. A method for producing the gas sensor according to claim 1, 2, 3, or 4,
Forming a sensor element in which a pair of electrodes are stacked via a solid electrolyte membrane, a pair of gas permeable conductors, and at least one through hole in a vertical direction of the pair of electrode covers; and
A step of clamping the sensor element with the electrode cover through the gas permeable conductor while inserting a positioning pin through the through hole of the sensor element, the gas permeable conductor and the electrode cover, and fixing the electrode cover A process for producing a gas sensor, comprising a step. A coin battery type gas sensor using the gas sensor according to claim 1, 2, 3 or 4.

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