JP5142323B2 - Hydrogen gas sensor - Google Patents

Description

  The present invention relates to a hydrogen gas sensor suitable for detection of hydrogen gas leaked into the atmosphere or detection of hydrogen concentration.

  In the future hydrogen energy utilization society, it is desired to construct a hydrogen energy utilization system that eliminates the danger of hydrogen explosion, is highly safe, and is convenient. For this purpose, development of a highly reliable hydrogen gas sensor capable of instantaneously and accurately detecting hydrogen gas leaking into the atmosphere is required.

  As such a hydrogen gas sensor, as shown in FIG. 10A, on a base material 100, two electrodes 101.102 made of materials having different chemical potentials with respect to hydrogen gas, and an electrolyte 103 interposed therebetween, A hydrogen gas sensor is provided. This is because the difference between the chemical potentials of the electrodes 101 and 102 with respect to the hydrogen gas is detected as an electromotive force, so that it is not necessary to provide a reference hydrogen gas pressure chamber or the like. Further, since the hydrogen gas concentration is detected based on the chemical potential, the hydrogen gas can be detected instantaneously.

  By the way, such a hydrogen gas sensor will be able to detect leakage earlier and more accurately by arranging it in a position close to a place where hydrogen may leak rather than vaguely arranging it in a wide space. That is easy to understand. For this purpose, as shown in FIG. 10B, the hydrogen gas sensor is formed on a tape-like base material 100, and this is a place where hydrogen may leak, for example, a connection flange or weld joint of a hydrogen gas pipe. Alternatively, it is conceivable to attach directly to the connection port between the outlet port of the hydrogen gas container and the pipe.

WO2005 / 080957 Publication

  However, in the conventional tape-shaped gas sensor, since the sensor is configured on one surface of the tape as the base material, the gas leaking from the pasting surface cannot be directly detected even if it is pasted on the leaking portion, and from the surroundings. The diffused gas was detected indirectly. On the other hand, if the sensor surface is directed to the leak location, that is, if the tape constituting the sensor is applied to the back side, the gas diffused from the surroundings cannot be detected, and even if the leak is detected directly on the back side, the leak gas Stays and accumulates, making it difficult to detect continuously and accurately.

  The present invention has been made in view of the above circumstances, and provides a hydrogen gas sensor capable of measuring leakage early and with high accuracy by arranging the sensor directly at a location where hydrogen gas leakage is expected. For the purpose.

In order to achieve the above object, the hydrogen gas sensor according to claim 1 includes a sensor structure unit including a first electrode and a second electrode made of different materials, and an electrolyte in contact with the electrodes. A hydrogen gas sensor that detects hydrogen gas based on an electromotive force value generated between these electrodes by contact with hydrogen gas, wherein the sensor structure portion is close to the through hole of the substrate on which a plurality of through holes are formed. A film is formed at the position where
The sensor structure is formed from the surface side of the base material having a front surface and a back surface, and does not reach the back surface from the surface through the micro through hole , and the inner surface of the micro through hole It is characterized in that the film is formed to reach

A hydrogen gas sensor according to a second aspect is the invention according to the first aspect, wherein the base material is a flat plate member having flexibility.
In invention of Claim 2, a base material is a flat member which has a softness | flexibility, and can also be easily attached to the surface of the curved member.

According to a third aspect of the present invention, in the hydrogen gas sensor according to the first or second aspect, the back surface of the base material is coated with an adhesive for attaching to the surface of the attachment object. Features.
In invention of Claim 3, it can attach to the surface of an attachment target object reliably with the adhesive agent apply | coated to the back surface of a base material.

According to a fourth aspect of the present invention, the hydrogen gas sensor according to the first aspect of the present invention is characterized in that the base material is formed in a shape that matches the shape of the object to be attached.
In the invention of claim 4, since the base material is formed in a shape that matches the shape of the object to be attached, it is easy to attach, and by fixing both in close contact, it is stable and reliable. High detection is performed.

The hydrogen gas sensor according to claim 5 is the invention according to claim 4, wherein the base material is provided with a structure for mechanically fixing the base material to an attachment target. To do.
In the invention described in claim 5, since the base material is mechanically fixed to the object to be attached, no adhesive is required and the replacement work is facilitated because it can be removed.

A hydrogen gas sensor according to a sixth aspect of the present invention is the invention according to any one of the first to fifth aspects, wherein the base material is provided with a transmission means for wirelessly communicating a detection signal from the sensor structure portion. It is characterized by.
According to the sixth aspect of the present invention, the wireless communication of the detection signal from the sensor structure unit eliminates the complexity due to the presence of wiring or the labor of wiring work, and the construction of a system for managing a plurality of sensors. Becomes easier.

  According to the first to sixth aspects of the invention, it is possible to measure the leakage early and with high accuracy by arranging the sensor directly at a position where hydrogen gas leakage is expected.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing the configuration of the hydrogen gas sensor of the present invention in principle, and FIG. 2 is an enlarged view showing the main part thereof. This hydrogen gas sensor includes a thin plate-like base material 10 having a plurality of through-holes 12 formed regularly or randomly, and a sensor structure 14 formed around the through-holes 12.

  As the base material 10, a flexible material suitable for a place where the hydrogen gas sensor is attached or an object is selected. Generally, a tape-like or sheet-like material made of a resin such as polyimide is convenient for being deformed and pasted so as to conform to the shape of the mounting portion. On the other hand, a rigid body formed in advance so as to conform to the shape of the object to be attached may be used, and in that case, it can be used so as to be fixed by a mechanical fixing structure such as a clamp or a bolt.

  The sensor structure 14 includes a detection electrode 16 and a reference electrode 18 having different chemical potentials for hydrogen gas, and a solid electrolyte 20 in contact with both. The solid electrolyte 20 is determined in consideration of the temperature range in which the sensor is used, the film formability during production, and other characteristics, but phosphotungstic acid and phosphomolybdic acid are preferred.

  The detection electrode 16 may be made of a material having a relatively high chemical potential of hydrogen, specifically, a material having a relatively high adsorption activity with respect to hydrogen gas, such as platinum, platinum alloy, palladium, and palladium alloy. it can. On the other hand, the reference electrode 18 is made of a material having a relatively low chemical potential of hydrogen, specifically, tungsten, nickel, titanium, titanium alloy, copper, iron, aluminum, or an alloy thereof, or an organic conductive material. It can be made of a material having a relatively low degree of adsorption activity for hydrogen gas.

  In this embodiment, each layer is formed by sputtering. First, the detection electrode 16 is formed on the substrate 10 so as to reach the inner surface from the peripheral portion on the front surface side of the through-hole 12. A lead wire 16 a is also integrally formed on the detection electrode 16. A film of the solid electrolyte 20 is formed so as to cover the detection electrode 16. The solid electrolyte 20 is formed by sputtering at a shallower angle, and a boundary line between the detection electrode 16 and the solid electrolyte 20 is formed on the inner surface of the through-hole 12. The reference electrode 18 is formed on the surface of the solid electrolyte 20. The lead wire 16a of the reference electrode 18 and the detection electrode 16 is connected to an electromotive force meter (not shown). Connection to the electromotive force meter is performed by wiring, but when incorporated on the base material 10 as described later, it can be directly connected on the base material.

  The hydrogen gas sensor configured as described above is used by attaching the back side to the surface of a member where hydrogen gas leakage is likely to occur. For this purpose, an adhesive may be applied in advance to a part or the entire surface of the back surface side and covered with a cover that can be easily peeled off. Also, it may be sold as a continuous long tape and cut and used as appropriate.

  The hydrogen gas sensor of this embodiment detects hydrogen gas by detecting an electromotive force generated when hydrogen gas reaches the contact portion (sensor structure portion 14) between the electrode and the electrolyte. Therefore, this sensor can detect both the hydrogen gas that has passed through the through-hole 12 and reached the sensor structure 14 and the hydrogen gas that has diffused and reached the atmosphere. Further, since the hydrogen gas generated from the back surface side is discharged from the through-hole 12, the generated hydrogen gas does not stay and detection can be continued by the recovery of the sensor structure section 14. Therefore, for example, it is possible to continuously check whether or not the leakage has stopped after the hydrogen gas leakage is detected and the measure for shutting off the supply of the hydrogen gas is taken.

  The shape and size of the base material 10 or the diameter and density of the through-holes 12 are appropriately selected according to the use location and purpose. In this embodiment, the hydrogen gas sensor formed in each through-hole 12 has the detection electrode 16 and the reference electrode 18 in common, and these sensors are connected in parallel. That is, the occurrence of leakage is detected by a detection signal from one of the sensors. On the other hand, if the signal is individually extracted from each sensor structure 14, it is possible to individually notify the location of leakage.

(Example)
Several types of hydrogen gas sensors having the configuration shown in FIGS. 1 and 2 were prepared, and a hydrogen detection test was performed. As the substrate 10, Example 1 is a polyimide tape having a thickness of 35 μm and a through hole 12 having a diameter of 0.35 μm is formed. Examples 2 and 3 are tetrafluoroethylene polymers having a thickness of 0.25 mm ( (Trade name: Teflon) tape having 0.75 mmΦ and 1.50 mmΦ through-holes 12 formed respectively. Moreover, sputtering was used for the film formation method of the sensor structure part 14.

  The test method is to measure an electromotive force generated between electrodes when hydrogen gas is blown onto a sensor from a hydrogen gas cylinder at an appropriate interval. As can be seen from FIG. 3, the hydrogen reaction characteristics of each example are illustrated, and hydrogen is detected rapidly. The recovery time required for the sensor to detect hydrogen and to be able to detect again after the surrounding hydrogen gas concentration has decreased is 1.8 seconds for Example 1 and 1.5 seconds for Example 2. Example 3 was 1.0 second, and it was found that the larger the diameter of the through-hole 12, the faster the recovery. There is no practical problem with the recovery time of any sensor.

  FIG. 4 shows another embodiment of the present invention, in which the through-hole 12 and the sensor are two-dimensionally arranged on a sheet that spreads in a plane instead of a tape. By arranging the sensors two-dimensionally in this way, it is possible to use a method of winding the entire length of the hydrogen pipe, for example, so as to completely check for leaks from the pipe at a relatively simple and low cost.

  In FIG. 5, the through-holes 12 and the sensors are two-dimensionally arranged on the sheet in the same manner as in FIG. Is. In this manner, by arranging the sensor structure 14 that operates individually in two dimensions, leakage of hydrogen gas from the attached member can be detected in more detail, and measures such as emergency measures can be taken. Become good easy. Also, in the case of detecting hydrogen gas diffusing from the surroundings, it becomes easy to identify the direction of the leakage source from the concentration gradient of each sensor, and to deal with it easily.

  FIG. 6 shows a hydrogen gas leakage management system using a tape-like or sheet-like hydrogen gas sensor as described above. That is, each hydrogen gas sensor is provided with a control unit 32. The control unit 32 transmits an electromotive force meter of each sensor structure unit 14, a microcomputer that processes an electromotive force signal, and a processing result. And a transmitter. Of course, it may be formed as a microprocessor in which these functions are integrated. A computer 36 having a receiver 34 is provided in the central management system at a predetermined position, and signals from a plurality of hydrogen gas sensors can be received to monitor and manage leakage.

  The control unit 32 includes identification information for specifying the attached hydrogen gas sensor, and the management system side can specify the signal source. Further, in the case where each sensor structure unit 14 is an individual type, the sensor structure unit 14 is provided with a function of transmitting a signal by specifying each sensor structure unit 14, so that a leak site can be specified in detail. When an object moves like a vehicle, a GPS function for specifying the position may be provided. The computer 36 on the management system side processes signals received from the hydrogen gas sensors, and performs operations such as issuing an alarm and stopping gas supply by opening / closing a valve in accordance with a predetermined protocol.

  By using a management system with such a communication function, even a facility distributed over a wide range can be managed efficiently and reliably without human intervention, and a safe hydrogen gas utilization system is constructed. Can contribute. Further, the hydrogen gas sensor incorporating the control unit 32 can be mass-produced at low cost by applying semiconductor manufacturing technology and the like, and the cost can be reduced.

  7 to 9 show another embodiment of the present invention, in which a substrate 10 having a predetermined shape is used. In the following embodiments, a highly rigid object such as resin, ceramic, or metal is used in addition to a flexible material depending on the purpose of use. In addition, when using a metal, an insulation process is required.

  FIG. 7 shows a ring-shaped thin plate as a base material 10a, and is similar to the previous embodiment in that minute through holes 12 and a sensor structure portion 14 are formed. This is attached to a tubular object such as a hydrogen gas pipe having a predetermined diameter. In the case of a pipe, the pipe is attached before the pipe work. When the diameter is standardized, it is convenient because it eliminates the need for mounting and does not require an adhesive. Of course, the piping may be entirely covered as being long in the axial direction, or a communication function as shown in FIG. 6 may be provided.

  FIG. 8A is a view showing the convenience of mounting the base member 10b as a coupling structure that can be opened and closed by a hinge 38. FIG. 8B is provided with a clamp 40 having a screw structure, and FIG. 8C is configured to elastically connect the claws 42 to each other. Of course, other mechanical couplings and couplings using adhesives, magnets, etc. can be employed as appropriate.

  FIG. 9 shows a state in which the hydrogen gas sensor of the embodiment of FIG. 7 or FIG. 8 is attached to a connection portion between a hydrogen gas container (gas cylinder) 44 and a pipe (gas hose) 46. In the case of the ring-shaped base material 10a shown in FIG. 7, it is good to shift and move what was previously attached to the piping side, after connecting piping and a cylinder. In the case of the openable base material 10b of FIG. 8, the inner surface may be provided with unevenness not only in a flat shape but also in conformity with the mounting portion.

  Thus, by manufacturing the base materials 10a and 10b in a shape suitable for the member to be attached, the installation work can be facilitated and the detection reliability can be improved. Since the pipes to be attached are standardized by standardization, the manufacturing cost of the sensor can be reduced by mass production. The base material itself may have a function as a specific part.

It is a figure which shows the structure of embodiment of the hydrogen gas sensor of this invention. It is a figure which expands and shows the principal part of the hydrogen gas sensor of FIG. It is a figure which shows the test result of the hydrogen gas sensor of embodiment of FIG. It is a figure which shows other embodiment of the hydrogen gas sensor of this invention. It is a figure which shows other embodiment of the hydrogen gas sensor of this invention. It is a figure which shows other embodiment of the hydrogen gas sensor of this invention. It is a figure which shows other embodiment of the hydrogen gas sensor of this invention. It is a figure which shows other embodiment of the hydrogen gas sensor of this invention. It is a figure which shows the use condition of the hydrogen gas sensor of embodiment of FIG. It is a figure which shows the conventional hydrogen gas sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a, 10b Base material 12 Through-hole 14 Sensor structure part 16 Detection electrode 18 Reference electrode 20 Solid electrolyte 32 Control part 34 Receiver 36 Computer 40 Clamp 42 Claw

Claims (6)

A sensor structure unit comprising a first electrode and a second electrode made of different materials and an electrolyte in contact with these electrodes, and based on an electromotive force value generated between these electrodes by contact with hydrogen gas A hydrogen gas sensor for detecting hydrogen gas,
The sensor structure part is formed into a film at a position close to the through hole of the base material on which a plurality of fine through holes are formed,
The sensor structure is formed from the surface side of the base material having a front surface and a back surface, and does not reach the back surface from the surface through the micro through hole , and the inner surface of the micro through hole A hydrogen gas sensor, wherein the film is formed so as to reach   The hydrogen gas sensor according to claim 1, wherein the base material is a flat plate member having flexibility.   The hydrogen gas sensor according to claim 1, wherein an adhesive for applying to the surface of the attachment object is applied to the back surface of the base material.   The hydrogen gas sensor according to claim 1, wherein the base material is formed in a shape that matches a shape of an object to be attached.   The hydrogen gas sensor according to claim 4, wherein the base material is provided with a structure for mechanically fixing the base material to an attachment target.   The hydrogen gas sensor according to any one of claims 1 to 5, wherein the base member is provided with a transmission unit for wirelessly communicating a detection signal from the sensor structure.

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