Inspection method of hydrogen tank

Abstract

The invention provides a technology capable of detecting abnormality of a hydrogen tank even if the hydrogen tank is not damaged. A method for inspecting a hydrogen tank having a cylindrical portion and two dome portions provided at both ends of the cylindrical portion includes: a step of filling the hydrogen tank with a fluid and applying a predetermined pressure; a step for acquiring a determined displacement amount, which is determined to be the maximum maximum value of the maximum displacement amount in the radial direction of the hydrogen tank at the dome portion or the maximum value of the displacement amount changing from increasing to decreasing; and a step for outputting the presence of an abnormality in the hydrogen tank when it is determined that the displacement amount is equal to or greater than the predetermined threshold value.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a method for inspecting a hydrogen tank. BACKGROUND

[0002] A technique capable of detecting a sign of damage of a hydrogen tank mounted on a fuel cell vehicle in advance is known. For example, a technique for detecting a sign of damage of a hydrogen tank based on acoustic emission generated in a case where a minute crack is generated in the hydrogen tank is disclosed in Patent Literature 1.

[0003] Patent Literature 1: International Publication No. 2009 / 008515

[0004] A technique capable of detecting an abnormality of a hydrogen tank even in a case where the hydrogen tank does not have damage is sought. SUMMARY

[0005] The present disclosure is achieved in order to solve the above-described problems, and can be implemented as the following modes.

[0006] According to the mode of the present disclosure, a method for inspecting a hydrogen tank having a cylindrical portion and two dome portions provided at both ends of the cylindrical portion is provided. The method includes a step of filling a fluid into the hydrogen tank and imparting a predetermined pressure, a step of acquiring a determination displacement amount that is a maximum displacement amount of the hydrogen tank in a radial direction of the dome portion or a maximum extreme value of the displacement amount from increasing to decreasing, and a step of outputting that an abnormality exists in the hydrogen tank in a case where the determination displacement amount is equal to or greater than a predetermined threshold value.

[0007] According to the inspection method of the mode, an abnormality of a hydrogen tank can be detected even in a case where the hydrogen tank does not have damage.

[0008] Further, the present disclosure can be implemented in various modes, for example, as an inspection device for a hydrogen tank, an inspection system, a control method of an inspection device, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is an explanatory diagram showing a structure of an inspection system.

[0010] Figure 2 is a flowchart showing an example of an inspection process.

[0011] Figure 3 is a diagram showing an example of a displacement amount of a tank main body.

[0012] EXPLANATION OF REFERENCE NUMERALS

[0013] 10…inspection system, 20…hydrogen tank, 21…tank main body, 22…joint, 23…cylindrical portion, 24…dome portion, 100…inspection device, 110…input / output interface, 120…storage portion, 130…CPU, 131…calculation portion, 132…determination portion, 200…imaging device. DETAILED DESCRIPTION

[0014] A. First Embodiment

[0015] Figure 1 is an explanatory view showing the structure of the inspection system 10 in the present embodiment. The inspection system 10 inspects abnormalities of the hydrogen tank 20. The inspection system 10 is provided with the inspection device 100 and the imaging device 200.

[0016] The hydrogen tank 20, for example, contains high-pressure hydrogen of 10 MPa to 70 MPa, and is mounted on a fuel cell vehicle. The hydrogen tank 20 is provided with the tank main body 21 and the joint 22.

[0017] The tank main body 21 has the cylindrical portion 23 and two dome portions 24 provided at both ends of the cylindrical portion 23. The dome portion 24 is a substantially hemispherical shape. The central axis of the cylindrical portion 23 and the central axis of the dome portion 24 are in agreement with the central axis of the hydrogen tank 20. The tank main body 21 is a member that does not transmit gas. The tank main body 21 is formed of a resin having gas barrier properties with respect to hydrogen, such as polyethylene, nylon, polypropylene, or the like. In the present embodiment, the tank main body 21 is made of resin, but can be made of metal.

[0018] A reinforcing layer is formed on the outer periphery of the cylindrical portion 23 and the dome portions 24. The reinforcing layer is formed, for example, by bundling 10,000 to 40,000 or so of fiber reinforced resin (CFRP) such as glass fiber, carbon fiber, or the like, and impregnating the fiber bundle with a thermosetting resin such as epoxy resin to form a fiber bundle, and further winding the formed fiber bundle around the outer periphery of the tank main body 21.

[0019] The joint 22 is a metal member that communicates the inside of the tank main body 21 with the outside. In the present embodiment, the joint 22 is provided at one end in the length direction of the tank main body 21, but can be provided at both ends.

[0020] The inspection device 100 is a device that inspects abnormalities of the hydrogen tank 20 using an image obtained by the imaging device 200 that photographs the hydrogen tank 20. The inspection device 100 is composed of a computer provided with an input / output interface 110, a storage portion 120, and a CPU 130. The input / output interface 110, the storage portion 120, and the CPU 130 are connected in a manner capable of bidirectional communication. The storage portion 120 is composed of a ROM and a RAM.

[0021] The CPU 130 realizes the functions of the calculation unit 131 and the determination unit 132 by executing a program installed in advance in the storage unit 120. However, a part or all of the functions of these units can be realized by a hardware circuit.

[0022] The calculation unit 131 calculates a displacement amount, which is the magnitude of displacement of each position of the dome portion 24 in the radial direction of the hydrogen tank 20, using an image acquired from the camera 200 via the input / output interface 110. The calculation unit 131 calculates the displacement amount, for example, by a digital image correlation (DIC) method. More specifically, the calculation unit 131 calculates the displacement amount based on the deformation of a pattern applied to the surface of the hydrogen tank 20.

[0023] When the displacement amount calculated by the calculation unit 131 is equal to or greater than a predetermined threshold value, the determination unit 132 determines that there is an abnormality in the hydrogen tank 20. The threshold value is a value determined in advance from test experience, and is a value indicating a low quality of strength. More specifically, the threshold value is a value indicating a high possibility that the tank main body 21 is broken from the dome portion 24 at an internal pressure lower than the target internal pressure in a rupture test. The rupture test is, for example, a test in which a fluid liquid is filled in the hydrogen tank 20 to increase the internal pressure of the hydrogen tank 20, and it is determined whether the expansion of the hydrogen tank 20 is within a reference, and whether the internal pressure at the time of rupture is within a reference.

[0024] Figure 2 is a flowchart indicating an example of an inspection process. This process is a process of detecting an abnormality of the hydrogen tank 20 in a pressure test. The pressure test is a test in which a fluid is filled in the hydrogen tank 20 and a predetermined pressure is applied. The pressure test is, for example, a test in which a liquid is filled in the hydrogen tank 20 to increase the internal pressure of the hydrogen tank 20, and it is determined whether the expansion of the hydrogen tank 20 is within a reference.

[0025] In step S100, a fluid is filled in the hydrogen tank 20, and a predetermined pressure is applied. More specifically, a liquid is filled in the hydrogen tank 20 until the internal pressure of the hydrogen tank 20 is increased to a predetermined value.

[0026] In step S110, the calculation unit 131 calculates a determination displacement amount in the dome portion 24 from an image captured by the camera 200. More specifically, the calculation unit 131 calculates the displacement amount of each position in the radial direction of the dome portion 24 of the hydrogen tank 20 before step S100 and the dome portion 24 of the hydrogen tank 20 after step S100 from the image captured by the camera 200, and determines the determination displacement amount. In the present embodiment, the determination displacement amount refers to the maximum maximum value among the maximum values in the distribution of the displacement amount of the dome portion 24 in a graph in which the position in the horizontal axis is the axis and the displacement amount in the vertical axis.

[0027] Figure 3is a graph indicating an example of the displacement amount of the tank main body 21. In Figure 3 In the graph shown, the horizontal axis indicates the position in the axial direction of the tank main body 21. The vertical axis indicates the displacement amount. The regression line G1 indicates the displacement amount in the normal case of the tank main body 21. The regression lines G2, G3, and G4 each indicate the displacement amount in the case where the tank main body 21 has an abnormality. The determination displacement amount of the regression line G1 is the displacement amount d1, the determination displacement amount of the regression line G2 is the displacement amount d2, the determination displacement amount of the regression line G3 is the displacement amount d3, and the determination displacement amount of the regression line G4 is the displacement amount d4. The displacement amount d1 is a value smaller than the threshold value dth, and the displacement amounts d2 and d3, d4 are each a value equal to or larger than the threshold value dth.

[0028] The determination section 132 determines in step S120 (refer to Figure 2 ) whether or not the determination displacement amount calculated in step S110 is equal to or larger than the threshold value dth decided in advance. The threshold value dth is a value equal to or smaller than the minimum displacement amount in the radial direction of the cylindrical portion 23, and is, for example, a value equal to or larger than 0.4 mm and equal to or smaller than 0.6 mm. In the case where the determination displacement amount is equal to or larger than the threshold value dth, the determination section 132 proceeds to the processing of step S130, and determines that the hydrogen tank 20 has an abnormality. In step S130, the determination section 132 can also notify the hydrogen tank 20 abnormality via a notification device not shown. On the other hand, in the case where the determination displacement amount is smaller than the threshold value dth, the determination section 132 proceeds to the processing of step S135, and determines that the hydrogen tank 20 has no abnormality.

[0029] According to the inspection method of the hydrogen tank 20 of the present embodiment described above, in the pressure resistance test, in the case where the expansion of the dome portion 24 is equal to or larger than the threshold value, it is determined that the hydrogen tank 20 has an abnormality. Therefore, even in the case where the hydrogen tank 20 has no damage, it is possible to detect an abnormality of the hydrogen tank 20.

[0030] B. Other Embodiments:

[0031] In the above-described embodiments, the determination displacement amount is the maximum value in the distribution graph in which the horizontal axis is the position in the axial direction and the vertical axis is the displacement amount of the dome portion 24. The determination displacement amount can also be only the displacement amount of the maximum value in the displacement amount of the dome portion 24.

[0032] The present disclosure is not limited to the above-described embodiments, and can be implemented in various structures without departing from the gist thereof. For example, the technical features in the embodiments corresponding to the technical features in each of the modes recited in the column of summary of the invention can be appropriately replaced or combined in order to solve the above-described problems or in order to achieve part or all of the above-described effects. In addition, if the technical features are not described as essential features in the present specification, they can be appropriately deleted.

Claims

1. A method for inspecting a hydrogen tank, the hydrogen tank having a cylindrical portion and two domed tops disposed at both ends of the cylindrical portion, wherein, The inspection methods for the hydrogen tank include: The process of filling the hydrogen tank with fluid and applying a predetermined pressure; The process of obtaining the determined displacement amount, wherein the determined displacement amount is the maximum radial displacement of the hydrogen tank at the dome or the maximum of the maximum values ​​of the displacement amount changing from increasing to decreasing; and If the determined displacement is above a predetermined threshold, the process of indicating an abnormality in the hydrogen tank is output.

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