JP2010266425A - Hydrogen pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen pressure sensor capable of reducing detection errors caused by the infiltration of hydrogen into a component member thereof. <P>SOLUTION: A detecting base material 10 includes a cylindrical section 16 and a diaphragm 18 blocking an opening at one end of the cylindrical section 16. The detecting base material 10 has a container shape comprising the cylindrical section 16 as a circling side wall and the diaphragm 18 as a bottom wall, and an inner wall surface of the container shape forms a pressure receiving hole 22. The hydrogen pressure sensor is fixed to hydrogen piping so that the opening in the detecting base material 10 is properly aligned with an opening formed at the hydrogen piping. The diaphragm 18 has a plurality of wall surface directional holes 24 extended from a peripheral rim surface toward the center of the diaphragm 18. A semiconductor strain gauge 14 is fixed to a sensor outer wall surface of the diaphragm 18 via an adhesive glass layer 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hydrogen pressure sensor that detects a hydrogen pressure based on distortion of sensor constituent members.

  Research and development have been extensively conducted on fuel cell vehicles that run on electric power supplied from the fuel cells. A fuel cell generates electric power through a chemical reaction between oxygen and hydrogen. Therefore, the fuel cell vehicle is equipped with a hydrogen tank, and generates electricity using hydrogen sent from the hydrogen tank and oxygen in the air sent from the outside. In order to detect the amount of hydrogen accumulated in the hydrogen tank, a hydrogen pressure sensor is provided in the hydrogen pipe attached to the hydrogen tank.

  Along with research on fuel cell vehicles, hydrogen stations that supply hydrogen as fuel to fuel cell vehicles have been developed. The hydrogen station is a hydrogen supply facility that includes a hydrogen pressure accumulator, a booster, various control valves, a hydrogen dispenser, and the like. Also in this facility, the hydrogen pressure sensor plays an important role for hydrogen flow control and hydrogen pressure control of each device.

  Thus, the hydrogen pressure sensor is an important component in fuel cell vehicles, hydrogen stations, and the like. However, the demand for measuring high-pressure hydrogen has been low so far, and a hydrogen pressure sensor suitable for fuel cell vehicles, hydrogen stations, etc. has not been developed. Under such circumstances, it is desired to develop an inexpensive and highly reliable hydrogen pressure sensor by adding improvements in accordance with the characteristics of hydrogen based on a gas pressure sensor already used in commercial automobile applications. .

  As a sensor for detecting the pressure of a fluid such as hydrogen, for example, there is one described in Patent Document 1 below. This pressure sensor includes a cylindrical member, and allows fluid to enter an opening at one end of the cylindrical member. The other end of the cylindrical member is closed with a plate-like member. This plate-like member is called a diaphragm and is elastically deformed according to the pressure of the fluid that has entered the cylindrical member. A strain detecting element for detecting elastic deformation of the diaphragm is attached to the outer surface of the pressure sensor of the diaphragm. According to such a pressure sensor, it is possible to detect the pressure of the fluid that has entered the cylindrical member by electrically detecting the strain amount by the strain detection element.

JP 2001-296198 A

  The diaphragm, the cylindrical member, and the like of the pressure sensor described in Patent Document 1 are made of metal. When hydrogen pressure is detected using this pressure sensor, hydrogen may diffuse and permeate into the diaphragm, and hydrogen may be released to the outside of the pressure sensor through the diaphragm. As a result, when hydrogen stays between the diaphragm and the strain detection element and the strain detection element is deformed by the staying hydrogen, an error may occur in the pressure detection value.

  The present invention has been made for such a problem. That is, an object of the hydrogen pressure sensor is to reduce detection errors caused by hydrogen permeating into its constituent members.

  The present invention relates to a hydrogen pressure sensor that includes a container-shaped member having a circumferential side wall and a bottom wall, and a strain sensor that detects deformation of the bottom wall, and detects a hydrogen pressure inside the container shape of the container-shaped member. The bottom wall includes a gas flow path for guiding gas from the inside of the member forming the bottom wall to the outside of the container-shaped member.

  Further, in the hydrogen pressure sensor according to the present invention, a wall-surface direction hole extending along the wall surface direction in the member forming the bottom wall and opening outside the container-shaped member is provided as the gas flow path. Is preferred.

  In the hydrogen pressure sensor according to the present invention, the bottom wall is formed so that the wall surface has a rotationally symmetric shape, and each extends from the inside of the member forming the bottom wall toward the outer peripheral direction of the rotationally symmetric shape. It is preferable that the plurality of wall surface direction holes are provided at rotationally symmetric positions.

  In the hydrogen pressure sensor according to the present invention, it is preferable that the bottom wall has a glass layer on an outer surface of the container-shaped member, and the strain sensor is fixed to the glass layer.

  Further, in the hydrogen pressure sensor according to the present invention, the bottom wall has a gas flow path layer formed of a porous member and forming the gas flow path on the outer surface of the container-shaped member, and the strain sensor It is preferable to be fixed to the gas flow path layer.

  In the hydrogen pressure sensor according to the present invention, it is preferable that the gas flow path layer includes glass particles.

  The hydrogen pressure sensor according to the present invention includes the strain sensor provided on the outer surface of the container-shaped member of the container-shaped member, and an adhesive glass or an organic adhesive for fixing the strain sensor to the container-shaped member. It is preferable to adopt a configuration including an adhesive member such as.

  Further, as an application example of the present invention, a hydrogen pipe for introducing hydrogen from a hydrogen supply source, a pressure detection opening provided in the hydrogen pipe, and an inner side of the container-shaped member so as to cover the pressure detection opening You may comprise the hydrogen supply apparatus provided with the said hydrogen pressure sensor attached to the opening for pressure detection.

  ADVANTAGE OF THE INVENTION According to this invention, the detection error by hydrogen osmose | permeating the structural member of a hydrogen pressure sensor can be reduced.

It is a figure which shows the structure of the hydrogen pressure sensor which concerns on 1st Embodiment. It is a figure which shows the structure of the hydrogen pressure sensor which concerns on a modification. It is a figure which shows the structure of the hydrogen pressure sensor which concerns on 2nd Embodiment. It is a figure which shows the structural example at the time of providing a hydrogen pressure sensor in hydrogen piping.

  FIG. 1 shows the configuration of a hydrogen pressure sensor according to the first embodiment of the present invention. FIG. 1A is a perspective view of a hydrogen pressure sensor. FIG. 1B is an AB cross-sectional view of the hydrogen pressure sensor, and FIG. 1C is a view of the hydrogen pressure sensor as viewed from above in FIG. The hydrogen pressure sensor includes a detection substrate 10, a bonding glass layer 12, and a semiconductor strain gauge 14.

  The detection base material 10 includes a cylindrical part 16 and a diaphragm 18 that closes an opening at one end of the cylindrical part 16. The detection base material 10 has a container shape in which the cylindrical portion 16 is a circumferential side wall and the diaphragm 18 is a bottom wall, and the inner wall surface of the container shape forms a pressure receiving hole 22. In the opening of the detection base material 10, a flange 20 having a thickness outside the edge of the cylindrical portion 16 is formed. The hydrogen pressure sensor is fixed to the hydrogen pipe so that the opening of the detection base material 10 matches the opening provided in the hydrogen pipe.

  Here, the cylindrical portion 16 has a cylindrical shape, and the diaphragm 18 has a disk shape. The shape of the cylindrical portion 16 is not limited to the cylindrical shape, and may be other cylindrical shapes according to the shape of the attachment destination. Moreover, you may deform | transform the cylindrical part 16 so that the magnitude | size of the opening of one end may differ from the magnitude | size of the opening of an other end.

  The material of the detection substrate 10 is preferably determined in consideration of strength and thermal expansion coefficient from the viewpoints of manufacturability and detection accuracy. Moreover, as a material of the detection base material 10, you may use metals with hydrogen embrittlement resistance, such as an iron nickel alloy and an iron nickel cobalt alloy. However, in the case of a general metal, there is often no problem even if hydrogen embrittlement resistance is not particularly considered as a material selection factor. Moreover, it is preferable that the cylindrical part 16, the diaphragm 18, and the flange 20 are integrally formed.

  The diaphragm 18 extends from the inside of the forming member toward the peripheral edge surface, and extends in the plurality of wall surface direction holes 24 opened to the peripheral edge surface, that is, extends from the peripheral edge surface of the diaphragm 18 toward the center of the diaphragm 18. A plurality of wall surface direction holes 24 are opened. FIG. 1 shows an example in which eight wall surface direction holes 24 are arranged so that the angles formed by the adjacent wall surface direction holes 24 are equal. Here, each wall surface direction hole 24 terminates in the middle of reaching the center of the diaphragm 18, but the wall surface direction hole 24 may penetrate the diaphragm 18. The wall surface direction hole 24 can be processed by a drill, wire discharge, or the like.

  A semiconductor strain gauge 14 is fixed to a sensor outer wall surface of the diaphragm 18 via an adhesive glass layer 12. As the bonding glass layer 12, it is preferable to use a material having a thermal expansion coefficient approximate to that of the detection substrate 10. The semiconductor strain gauge 14 can be fixed by, for example, melting the bonding glass layer 12 and solidifying the bonding glass layer 12 with the semiconductor strain gauge 14 in contact with the molten bonding glass layer 12.

  Here, the case where glass is used as a member for fixing the semiconductor strain gauge 14 to the detection base material 10 is taken up. However, as this member, the thermal expansion coefficient is close to that of the detection base material 10 and other adhesive strength can be obtained. These materials may be used.

  From the semiconductor strain gauge 14, two detection conductors 26 for detecting the resistance value are drawn out. The resistance value of the semiconductor strain gauge 14 changes due to deformation. The change in resistance value can be detected by using the drawn detection lead wire 26. A protective layer made of silicon or the like that protects the semiconductor strain gauge 14 may be provided on the upper layer of the semiconductor strain gauge 14.

  Next, the operation of the hydrogen pressure sensor according to this embodiment will be described. The diaphragm 18 is elastically deformed by the pressure of hydrogen entering the pressure receiving hole 22 from the opening of the detection substrate 10. As a result, the semiconductor strain gauge 14 is elastically deformed by receiving a force from the diaphragm 18 via the bonding glass layer 12, and the resistance value changes according to the elastic deformation. The pressure detection device connected to the two detection conductors 26 determines the hydrogen pressure in the pressure receiving hole 22 based on the resistance value between the detection conductors 26.

  Hydrogen in the pressure receiving hole 22 permeates the diaphragm 18 by the pressure. The hydrogen that has permeated the diaphragm 18 is released into the wall surface direction hole 24 when the distance to the wall surface direction hole 24 is shorter than the distance to the bonding glass layer 12, and is guided to the wall surface direction hole 24 to be detected substrate. 10 to the outside. As described above, the wall surface direction hole 24 functions as a gas flow path that guides hydrogen from the diaphragm 18 to the outside of the pressure receiving hole 22.

  In the conventional gas pressure sensor, the wall surface direction hole 24 is not provided in the diaphragm 18. In such a conventional configuration, when the hydrogen that has passed through the diaphragm 18 reaches the bonding glass layer 12, the hydrogen enters the bubbles formed in the bonding glass layer 12, thereby deforming the bonding glass layer 12 and hydrogen. The inventors' investigation has revealed that an error occurs in the detected pressure value.

  According to the hydrogen pressure sensor according to the first embodiment of the present invention, the amount of hydrogen reaching the bonding glass layer 12 from the pressure receiving hole 22 through the diaphragm 18 can be reduced, and the bonding glass layer by the entry of hydrogen. Twelve deformations can be avoided. Thereby, the error of the hydrogen pressure detected by the semiconductor strain gauge 14 can be reduced.

  As a configuration example of the hydrogen pressure sensor, the inner diameter (diameter) of the pressure receiving hole 22 in the cylindrical portion 16 is 1 mm or more and 5 mm or less, the thickness of the cylindrical portion 16 is more than 1 mm, and the thickness of the diaphragm 18 is 0.2 mm or more. Examples thereof include 1.0 mm or less, a diameter of the surface of the bonding glass layer of 1 mm to 5 mm, and a thickness of the bonding glass layer 12 of 30 μm to 100 μm.

  In this case, a hydrogen pressure of 10 MPa or more and 200 MPa or less can be detected by using a semiconductor strain gauge widely used at the time of filing this application. Since the hydrogen pressure in the high-pressure hydrogen pipe used for the fuel cell vehicle is 10 MPa or more and 100 MPa or less, this configuration example can be said to be suitable for the fuel cell vehicle.

  With respect to the shape and size of the detection base material 10, the number of wall surface direction holes 24, the positions where the wall surface direction holes 24 are provided, etc., in view of the strength, rigidity, detection error reduction effect, etc. of the detection base material 10, experiments and simulations are performed. It is preferable to optimize based on the above.

  FIG. 2 shows a configuration of a hydrogen pressure sensor according to a modification. This figure shows the hydrogen pressure sensor as viewed from the semiconductor strain gauge 14 side. The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. In this hydrogen pressure sensor, short wall surface direction holes 24S are provided between the wall surface direction holes 24 in the hydrogen pressure sensor of FIG. 1, and the total number of wall surface direction holes 24 and 24S is 16. By arranging the wall surface direction holes 24 and 24S at equiangular intervals, the diaphragm 18 can have a rotationally symmetric structure with respect to an axis that passes through the center of the diaphragm 18 perpendicularly to the wall surface. By making the diaphragm 18 have a rotationally symmetric structure, the rigidity of the diaphragm 18 can be made uniform.

  FIG. 3 shows the configuration of a hydrogen pressure sensor according to the second embodiment of the present invention. FIG. 3A is a perspective view of the hydrogen pressure sensor. 3B is an AB cross-sectional view of the hydrogen pressure sensor, and FIG. 3C is an enlarged cross-sectional view of the gas flow path layer 28. The same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  This pressure sensor is obtained by replacing the bonding glass layer 12 included in the hydrogen pressure sensor according to the first embodiment with a gas flow path layer 28. Further, as shown in FIGS. 3A and 3B, the diaphragm 18 does not have to be provided with the wall surface direction hole 24.

  The gas flow path layer 28 is preferably formed of a material such as glass or ceramic. The gas flow path layer 28 includes a porous layer 30 provided on the upper layer of the diaphragm 18 and an adhesive layer 34 provided on the upper layer of the porous layer 30. The porous layer 30 is formed of a porous member having a plurality of pores having a diameter of several μm to several hundred μm (for example, 2 μm to 100 μm). The adhesive layer 34 is a layer that fixes the semiconductor strain gauge 14 to the gas flow path layer 28.

  When the gas flow path layer 28 is formed of glass, the porous layer 30 is formed by bonding glass particles 32 having a diameter of several μm to several hundred μm (for example, 2 μm to 100 μm) as shown in FIG. It may be formed. The diaphragm 18, the gas flow path layer 28, and the semiconductor strain gauge 14 may be fixed by melting the glass forming the gas flow path layer 28 and then solidifying it.

  Next, the operation of the hydrogen pressure sensor according to this embodiment will be described. The diaphragm 18 is elastically deformed by the pressure of hydrogen entering the pressure receiving hole 22 from the opening of the detection substrate 10. As a result, the semiconductor strain gauge 14 is elastically deformed by receiving a force from the diaphragm 18 via the gas flow path layer 28, and the resistance value changes according to the elastic deformation. The pressure detection device connected to the two detection conductors 26 determines the hydrogen pressure in the pressure receiving hole 22 based on the resistance value between the detection conductors 26.

  The hydrogen in the pressure receiving hole 22 penetrates the diaphragm 18 by the pressure and permeates to the gas flow path layer 28. The hydrogen that has reached the gas flow path layer 28 is released to the outside of the detection substrate 10 through the holes of the porous layer 30.

  According to the hydrogen pressure sensor according to the second embodiment of the present invention, the hydrogen that has passed through the diaphragm 18 from the pressure receiving hole 22 to reach the gas flow path layer 28 passes through the hole of the porous layer 30 and the detection substrate 10. To the outside. Therefore, deformation of the gas flow path layer 28 due to the entry of hydrogen is avoided. Thereby, the error of the hydrogen pressure detected by the semiconductor strain gauge 14 can be reduced.

  Note that the hydrogen sensor according to the second embodiment may have a structure in which the wall surface direction hole 24 is provided in the diaphragm 18 as in the first embodiment.

  FIG. 4 is a cross-sectional view showing a configuration example when the hydrogen pressure sensor according to the first embodiment is provided in a hydrogen pipe used in a fuel cell vehicle, a hydrogen pipe of a hydrogen supply device used in a hydrogen station, or the like. The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  A detection branch pipe 38 for detecting the hydrogen pressure is attached to the hydrogen pipe 36. The opening end of the detection branch pipe 38 is formed so as to coincide with the opening of the hydrogen pressure sensor. The hydrogen pressure sensor is attached to the detection branch pipe 38 so that its flange 20 matches the open end of the detection branch pipe 38. The hydrogen pressure sensor can be fixed using a member (not shown) that presses the hydrogen pressure sensor against the detection branch pipe 38 while being in contact with the flange upper surface 40.

  Hydrogen in the hydrogen pipe 36 enters the pressure receiving hole 22 from the opening of the hydrogen pressure sensor. Hydrogen applies pressure to the wall surface of the pressure receiving hole 22. According to such a configuration, the hydrogen pressure in the hydrogen pipe 36 can be detected by detecting the resistance value between the detection conductors 26 drawn from the hydrogen pressure sensor.

  Here, the example in which the hydrogen pressure sensor according to the first embodiment is provided in the hydrogen pipe has been described. However, the hydrogen pressure sensor according to the second embodiment is also configured in the same manner as the hydrogen pressure sensor according to the first embodiment. Can be attached to piping.

  The hydrogen pressure sensor according to the present invention can be used for fuel cell vehicles, devices for supplying hydrogen to fuel cell vehicles, and general hydrogen supply equipment for supplying hydrogen at high pressure.

  DESCRIPTION OF SYMBOLS 10 Detection base material, 12 Adhesion glass layer, 14 Semiconductor strain gauge, 16 Cylindrical part, 18 Diaphragm, 20 Flange, 22 Pressure receiving hole, 24 Wall surface direction hole, 26 Detection conducting wire, 28 Gas flow path layer, 30 Porous layer, 32 Glass particles, 34 Adhesive layer, 36 Hydrogen piping, 38 Detection branch pipe, 40 Flange upper surface.

Claims (6)

A container-shaped member comprising a circumferential wall and a bottom wall;
A strain sensor for detecting deformation of the bottom wall;
With
In the hydrogen pressure sensor for detecting the hydrogen pressure inside the container shape of the container-shaped member,
The bottom wall is
A hydrogen pressure sensor comprising a gas flow path for guiding gas from the inside of the member forming the bottom wall to the outside of the container-shaped member. The hydrogen pressure sensor according to claim 1,
A hydrogen pressure sensor, characterized in that a wall direction hole extending along a wall surface direction in a member forming the bottom wall and opening to the outside of the container-shaped member is provided as the gas flow path. The hydrogen pressure sensor according to claim 2,
The bottom wall is
The wall is formed in a rotationally symmetric shape,
A hydrogen pressure sensor, wherein a plurality of wall surface direction holes each extending from a member forming the bottom wall toward an outer peripheral direction of a rotationally symmetric shape are provided at rotationally symmetric positions. The hydrogen pressure sensor according to any one of claims 1 to 3,
The bottom wall is
Having a glass layer on the outer surface of the container-shaped member,
The strain sensor
A hydrogen pressure sensor fixed to the glass layer. The hydrogen pressure sensor according to any one of claims 1 to 4,
The bottom wall is
A gas channel layer formed of a porous member and forming the gas channel is provided on the outer surface of the container-shaped member,
The strain sensor
A hydrogen pressure sensor fixed to the gas flow path layer. The hydrogen pressure sensor according to claim 5,
The gas flow path layer is
A hydrogen pressure sensor comprising glass particles.

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