JP6261010B2 - Hydrogen remaining amount sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a hydrogen remaining amount sensor for detecting the remaining amount of hydrogen in a hydrogen storage container or the like containing a hydrogen storage alloy.

A hydrogen storage alloy container, which is one of the hydrogen storage containers, has begun to spread due to its excellent volume storage density, but there is a problem that it is difficult to obtain a clue to know the remaining amount of hydrogen in the hydrogen storage alloy container. If it is a normal hydrogen gas tank, the remaining amount of hydrogen can be easily known by attaching a pressure gauge. On the other hand, in the case of a hydrogen storage alloy, there is a flat region called a plateau represented by a PCT curve. In addition to the small pressure difference (minimum and maximum pressure difference) here, this plateau will change if the temperature of the alloy changes. Since the pressure of the gas also changes, it is difficult to accurately know the remaining amount of hydrogen in the container using only a pressure gauge.
In a hydrogen storage system for a large hydrogen storage alloy container, this is an indirect measurement method, but the remaining amount of hydrogen can be known from the integrated value using a high-precision mass flow meter. However, since the mass flow meter is expensive and difficult to downsize, it can be said that it is not suitable for a relatively small hydrogen storage alloy container. Therefore, a hydrogen remaining amount meter or sensor that can directly know the remaining amount of hydrogen suitable for this hydrogen storage alloy container has been proposed.

The method for measuring the remaining amount of hydrogen proposed in Patent Document 1 is a method in which a strain gauge is directly attached to the wall of a tank.
The method for detecting the remaining amount of hydrogen proposed in Patent Document 2 is a method in which three hydrogen storage alloys having different hydrogen storage pressures and a micro heater are combined in a tank.
The hydrogen remaining amount sensor proposed in Patent Document 3 is filled with a hydrogen storage alloy in a small sensor body, and a strain sensor is attached to the sensor, thereby detecting expansion of the hydrogen storage alloy due to hydrogen absorption and It is a way to know the quantity.

JP-A-6-66787 JP 2005-106617 A JP 2008-180682 A

However, in the method according to Patent Document 1, since the expansion deformation of the tank accompanying the expansion of the alloy varies depending on the location, it is considered that the accuracy is lacking unless there are a plurality of strain gauges.
Further, the method according to Patent Document 2 is a complicated mechanism, and it is considered difficult to manufacture at a low cost.
Furthermore, in the hydrogen remaining amount sensor in Patent Document 3, a graph showing the relationship between the remaining amount of hydrogen and the output is shown in the embodiment. However, the output waveform has a flat portion in a region where the hydrogen absorption rate is high, and the remaining amount of hydrogen. There is a problem that accuracy is difficult due to poor linearity between the output and the output.

  This invention was made in order to solve the problem of the remaining amount of hydrogen sensor in the background of the above circumstances, and by increasing the filling rate of the hydrogen storage alloy, the sensor output is increased and the remaining amount of hydrogen is detected with high accuracy. It is an object of the present invention to provide a hydrogen remaining amount sensor and a manufacturing method thereof.

That is, among the remaining hydrogen sensors of the present invention, the first embodiment is a remaining hydrogen sensor disposed in a space where hydrogen is absorbed and released by the main hydrogen storage alloy, and the hydrogen storage alloy for the sensor. The container body is filled with a powder having a filling rate of more than 60%, and the hydrogen body can be moved in and out. The sensor body is distorted as the hydrogen storage alloy for the sensor absorbs and releases hydrogen. Has an easy strain part that easily occurs, and a strain gauge for measuring the strain of the easy strain part is provided ,
The sensor main body has a cylindrical shape with a notch on the wall surface along the axial direction. The axial length is in the range of 5 mm to 30 mm, and the ratio of the diameter to the axial length is 1: 2 to 1: in the range of 4, the hydrogen remaining sensor, wherein the pipe strength is ^{3.0 N / mm 2 ~25.0N / mm} 2.
However, the filling rate is Ri filling rate der respect to the initial volume of the sensor body, the pipe strength is a value obtained from 2 (t / D) σYs, t: wall thickness, D: pipe diameter, ShigumaYs: in Strength Oh Ru.

  The hydrogen residual sensor of the second aspect is characterized in that, in the present invention of the above aspect, the sensor main body is filled with only a hydrogen storage alloy for a sensor as a filling material.

  According to a third aspect of the present invention, in the hydrogen residue sensor according to the first aspect, the sensor body has a cylindrical shape, and the hydrogen storage alloy for the sensor expands by 2% to 5% in the longitudinal direction of the cylinder cross section. It is characterized by being filled with a filling amount.

Of the method for producing a hydrogen residue sensor according to the present invention, the first embodiment is a method for producing a hydrogen remaining amount sensor disposed in a space where hydrogen is absorbed and released by a main hydrogen storage alloy,
It is possible to move hydrogen in and out, a part of which is easily distorted, which is easily distorted with hydrogen absorption and release , has a notch along the axial direction on the wall surface, and has an axial length of 5 mm. in the range of ～30Mm, size and ratio of the axial length of the diameter is 1: 2 to 1: in the range of 4, cylindrical shape pipe strength is ^{3.0 N / mm 2 ~25.0N / mm} 2 The sensor body is filled with hydrogen storage alloy powder for the sensor at a filling rate of more than 60% and in a filling amount that expands by 2% to 5% in the longitudinal direction of the cylinder cross section,
A strain gauge for measuring the strain of the easy strain portion is provided.
However, the filling rate is Ri filling rate der respect to the initial volume of the sensor body, the pipe strength is a value obtained from 2 (t / D) σYs, t: wall thickness, D: pipe diameter, ShigumaYs: in Strength Oh Ru.

According to the present invention, by filling the sensor body with a sufficient amount of powdered hydrogen storage alloy, the strain output in the sensor body accompanying hydrogen absorption can be obtained with high accuracy, thereby accurately determining the remaining amount of hydrogen. Make it possible to know.
That is, it is possible to efficiently transmit the expansion of the hydrogen storage alloy to the sensor main body, thereby providing a remaining amount sensor that can detect and output the remaining amount of hydrogen with high accuracy.

In addition, when filling, if the cylinder cross-sectional diameter of the sensor body expands to an extent that expands 2-5% from the original size, it is possible to increase the strain output and detect the alloy expansion accurately even in the low hydrogen concentration region. It becomes.
Furthermore, if the axial length of the sensor main body is optimized with respect to the cross-sectional length of the cylinder, the force due to the alloy expansion can be transmitted to the sensor main body without waste, and the sensor output can be highly accurate.

It is a perspective view of the hydrogen residual amount sensor of one Embodiment of this invention. Similarly, it is a figure explaining operation | movement of a hydrogen remaining amount sensor. It is the graph which showed the relationship between the hydrogen residual amount and distortion in the Example of this invention. It is a figure which shows the relationship of the sensor main body alloy filling rate in the Example of this invention, hydrogen remaining amount, and a sensor output waveform.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
First, the hydrogen storage alloy for the sensor that fills the sensor body is generally the same as the hydrogen storage alloy (main hydrogen storage alloy) housed in the hydrogen storage container or the like for which the remaining amount is to be measured. However, a hydrogen storage alloy different from the main hydrogen storage alloy may be filled as long as a characteristic capable of accurately detecting the remaining amount is obtained. The hydrogen storage alloy is prepared in a powder form for filling. The particle size of the hydrogen storage alloy powder is not particularly limited and can be set to an appropriate size. For example, a particle size of 100 μm to 1000 μm is desirable.

  The sensor body 1 has a cylindrical shape with both axial ends open, and is made of an aluminum material. Examples of the aluminum alloy include JIS A1070. However, the present invention is not limited to this material even when an aluminum material is used for the sensor body 1. The sensor body 1 is preferably a cylindrical sensor body as shown in FIG. However, in the present invention, the shape and material of the sensor main body are not particularly limited.

The sensor body 1 is preferably manufactured using an aluminum alloy pipe having a pipe strength of 3.0 N / m ^{2 to} 15.0 N / m ² . The pipe strength is a value obtained from 2 (t / D) σYs, where t is the wall thickness, D is the pipe diameter, and σYs is the yield strength. If the pipe strength is too low, plastic deformation occurs with the deformation of the sensor main body due to the absorption of hydrogen, making it impossible to measure the remaining amount of hydrogen. On the other hand, if the pipe strength is too high, the amount of distortion due to hydrogen release becomes small, making it difficult to detect the remaining amount of hydrogen with high accuracy.

  Moreover, the sensor main body 1 has the notch part 2 over the axial direction full length in a cylinder wall, and has a cross-sectional C shape. The inside of the cylinder of the sensor body 1 is a hydrogen storage alloy filling portion for the sensor. The opposite cylindrical wall of the notch portion 2 is an easily distorted portion 3 where stress concentrates when each sensor body is deformed with the notch portion 2 as an open end. The strain gauge 4 shown is affixed.

  The sensor body 1 is filled with hydrogen storage alloy powder 5. The filling method can be performed by an appropriate method, and the filling method is not particularly limited in the present invention. The hydrogen storage alloy is preferably filled at a filling rate of more than 60% with respect to the initial volume of the inner volume of the sensor body, and more preferably at a filling rate of 65% or more. Further, when filling, it is desirable to fill so as to expand 2% to 5% in the longitudinal direction of the cylinder cross section.

The sensor body preferably has a diameter of 5 to 12 mm and an axial length of 10 mm to 30 mm, and the ratio of the diameter to the axial length is 1: 2 to 1: More preferably, it is within the range of 4.
In this embodiment, the sensor output is highly accurate by appropriately setting the length of the hydrogen remaining amount sensor in the main body axial direction. When the axial length is short, the force due to the alloy expansion is not transmitted in the radial direction, but easily escapes in the axial direction. When the axial length is long, the alloy filling is likely to be uneven, and the output waveform becomes unstable. Axial length for the same reason, it is desirably on the 10 m m or more, even more desirably set to 30mm or less.

  In addition, the accuracy of the sensor output can be ensured by appropriately setting the ratio between the diameter and the axial length. When the ratio is small, the transmission of force due to the expansion of the alloy is deteriorated, and when the ratio is large, the alloy filling unevenness is likely to occur.

FIG. 2 is a schematic diagram showing a deformation associated with hydrogen absorption / release of the filling portion filled with the hydrogen storage alloy powder 5 for sensor in the C-type sensor body 1. When the hydrogen storage alloy expands by absorbing hydrogen, the sensor body 1 is elastically deformed so as to open the open end of the notch 2, so that the strain concentrates on the easy strain portion 3 on the opposite side of the open end, The strain gauge 4 receives compressive stress. The strain of the easy strain portion 3 is detected by the strain gauge 4.
In the above embodiment, the sensor body 1 is filled with the alloy until the sensor body diameter expands by 2 to 5% from the original size, and the volume of the hydrogen storage alloy filling space of the initial sensor body is larger than that of the hydrogen storage alloy. The filling rate is 65% or more. This makes it easier for strain to change even when the hydrogen absorption rate is low, and the excellent characteristics of the fuel gauge can be obtained. By filling the sensor body to a filling rate of 65% or more, the remaining amount sensor output can be increased to about 1.5 times that of the conventional technology, and the alloy expansion can be detected accurately even in a low hydrogen concentration region. It becomes possible.

An embodiment of the present invention will be described below.
An aluminum alloy C-shaped tube (Dφ 5 mm, L 20 mm) having a wall thickness of 0.25 mm is used as the sensor body for the remaining amount sensor so as to have the same shape as in FIG. However, L: sensor body length, D: sensor body diameter, t: sensor body thickness, and pipe strength was 3.40 N / mm ² .
Inside the sensor body, AB ₅ type hydrogen absorbing alloy powder filling rate of filled to about 72% (hydrogen storage alloy by weight 1.8 g). After filling with the hydrogen storage alloy resin mixture, a KFG type strain gauge manufactured by Kyowa Dengyo was attached. It was measured that the expansion in the radial direction was expanded to about 5.2 mm at the end of the alloy filling. Therefore, an expansion of about 4% was seen.

  A hydrogen storage container for testing was filled with 90 g of the same hydrogen storage alloy powder as that filled in the sensor body, and inserted near the center of the hydrogen storage alloy filling portion. The gap around the sensor body was filled with ceramic wool. The strain gauge output line was drawn to the outside through a joint and connected to a data collection device so that strain could be recorded as needed. A hydrogen introduction valve was attached to the hydrogen storage container.

  The hydrogen storage container was evacuated by a rotary pump at 80 ° C. for 10 hours and then immersed in a water bath at 15 ° C. to introduce 1 MPa of hydrogen to activate. After activation, hydrogen absorption and desorption was repeated four times to stabilize the output. Next, after fully filling 1 MPa of hydrogen at 20 ° C., a change in strain was recorded when hydrogen was released to atmospheric pressure at a maximum speed of 0.1 NL / min. A graph in which the remaining amount of hydrogen in the hydrogen storage container is plotted on the horizontal axis and the strain at that time is plotted on the vertical axis is shown in FIG.

The remaining amount of hydrogen is measured using a high-precision mass flow meter, and the integrated value is a percentage. As shown in Fig. 3, the amount of strain tends to increase along a straight line with the release of hydrogen (compression strain is eliminated), so the sensor can be used to accurately display the remaining amount. It became.
FIG. 4 shows a relationship diagram of the sensor body alloy filling rate, the remaining amount of hydrogen, and the maximum value of the error of the sensor output waveform. From FIG. 4, it is preferable that the filling rate is 65% or more in order to make the filling rate 10% or less with respect to the filling rate. Further, when an error of 8% or less is required, the filling rate is desirably 70% or more.

  As mentioned above, although this invention was demonstrated based on the said embodiment, an appropriate change with respect to this embodiment is possible unless it deviates from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Sensor main body 2 Notch part 3 Easy strain part 4 Strain gauge 5 Hydrogen storage alloy powder

Claims (4)

A hydrogen remaining amount sensor disposed in a space where hydrogen is absorbed and released by a main hydrogen storage alloy, wherein the hydrogen storage alloy powder for the sensor is filled at a filling rate exceeding 60%, and the movement of the hydrogen in and out A container-shaped sensor main body, the sensor main body partly having an easily distorted portion that easily distorts due to hydrogen absorption / release of the hydrogen storage alloy for the sensor, A strain gauge is provided to measure the strain of
The sensor main body has a cylindrical shape with a notch on the wall surface along the axial direction. The axial length is in the range of 5 mm to 30 mm, and the ratio of the diameter to the axial length is 1: 2 to 1: in the range of 4, the hydrogen remaining sensor, characterized in that the pipe strength, has a strength of ^{3.0 N / mm 2 ~25.0N / mm} 2.
However, the filling rate is Ri filling rate der respect to the initial volume of the sensor body, the pipe strength is a value obtained from 2 (t / D) σYs, t: wall thickness, D: pipe diameter, ShigumaYs: in Strength Oh Ru.   2. The hydrogen remaining amount sensor according to claim 1, wherein the sensor main body is filled only with a hydrogen storage alloy for a sensor as a filling material. 3. The remaining hydrogen sensor according to claim 1 , wherein the sensor main body is filled with the hydrogen storage alloy for the sensor in a filling amount that expands by 2% to 5% in the longitudinal direction of the cylinder cross section. A method for manufacturing a hydrogen remaining amount sensor disposed in a space where hydrogen is absorbed and released by a main hydrogen storage alloy,
It is possible to move hydrogen in and out, a part of which is easily distorted, which is easily distorted with hydrogen absorption and release , has a notch along the axial direction on the wall surface, and has an axial length of 5 mm. in the range of ～30Mm, size and ratio of the axial length of the diameter is 1: 2 to 1: in the range of 4, the pipe strength ^is 3.0N / mm ² ~25.0N / mm 2 cylinder Fill the mold-shaped sensor body with the hydrogen storage alloy powder for the sensor at a filling rate of more than 60% and a filling amount that expands by 2% to 5% in the longitudinal direction of the cylinder cross section,
A method of manufacturing a hydrogen remaining amount sensor, comprising: a strain gauge for measuring strain of the easy strain portion.
However, the filling rate is Ri filling rate der respect to the initial volume of the sensor body, the pipe strength is a value obtained from 2 (t / D) σYs, t: wall thickness, D: pipe diameter, ShigumaYs: in Strength Oh Ru.

Images