Method for inspecting hydrogen tank

Abstract

To provide a technique capable of detecting abnormality of a hydrogen tank even when the hydrogen tank is not damaged.SOLUTION: An inspection method for a hydrogen tank including a tank body that stores hydrogen and a cap that is provided at an end portion of the tank body and includes a cylindrical portion and a flange portion protruding from the cylindrical portion in a radial direction of the cylindrical portion includes a step of filling the hydrogen tank with a fluid and applying a predetermined pressure, a step of acquiring a displacement difference that is a difference between a displacement amount of a first portion of the tank body in contact with the cylindrical portion in an axial direction of the tank body and a displacement amount of a second portion of the tank body in contact with the flange portion in the axial direction, and a step of outputting that there is an abnormality in the hydrogen tank when the displacement difference is equal to or greater than a predetermined threshold value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] There are known technologies that can detect early signs of damage to hydrogen tanks installed in fuel cell vehicles. For example, Patent Document 1 discloses a technology that detects signs of damage to a hydrogen tank based on acoustic emissions that occur when a small crack occurs in the hydrogen tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2009 / 008515 Summary of the Invention [Problem to be solved by the invention]

[0004] There was a need for technology that could detect abnormalities in hydrogen tanks even when there was no damage to the hydrogen tank. [Means for solving the problem]

[0005] The present disclosure has been made to solve the above-mentioned problems, and can be realized in the following forms.

[0006] According to an embodiment of the present disclosure, there is provided a method for inspecting a hydrogen tank having a tank body that stores hydrogen and a nozzle that is attached to an end of the tank body and has a cylindrical portion and a flange that protrudes radially from the cylindrical portion. This inspection method includes the steps of filling the hydrogen tank with a fluid and applying a predetermined pressure, obtaining a displacement difference that is the difference between the amount of displacement in the axial direction of the tank body of a first portion of the tank body that is in contact with the cylindrical portion and the amount of displacement in the axial direction of the tank body of a second portion of the tank body that is in contact with the flange, and outputting an indication that there is an abnormality in the hydrogen tank if the displacement difference is equal to or greater than a predetermined threshold. According to this type of inspection method, an abnormality in the hydrogen tank can be detected even if the hydrogen tank is not damaged.

[0007] The present disclosure can be realized in various forms, for example, in the form of an inspection device or inspection system for hydrogen tanks, a control method for an inspection device, and the like. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an explanatory diagram illustrating a configuration of an inspection system. [Figure 2] 10 is a flowchart illustrating an example of an inspection process. [Figure 3] FIG. 2 is a cross-sectional view of the nozzle portion of the hydrogen tank. DETAILED DESCRIPTION OF THE INVENTION

[0009] A. First embodiment: 1 is an explanatory diagram showing the configuration of an inspection system 10 in this embodiment. The inspection system 10 inspects a hydrogen tank 20 for abnormalities. The inspection system 10 includes an inspection device 100 and an imaging device 200.

[0010] The hydrogen tank 20 contains high-pressure hydrogen of, for example, 10 to 70 MPa, and is mounted on a fuel cell vehicle. The hydrogen tank 20 comprises a tank body 21 and a mouthpiece 22.

[0011] The tank body 21 has a cylindrical portion 23 and two dome portions 24 provided on both ends of the cylindrical portion 23. The dome portions 24 are generally hemispherical in shape. The central axis of the cylindrical portion 23 and the central axis of the dome portions 24 both coincide with the central axis of the hydrogen tank 20. The tank body 21 is a gas-impermeable material. The tank body 21 is formed from a resin that has gas barrier properties against hydrogen gas, such as polyethylene, nylon, or polypropylene. In this embodiment, the tank body 21 is made of resin, but it may also be made of metal.

[0012] A reinforcing layer is formed on the outer periphery of the cylindrical portion 23 and the dome portion 24. The reinforcing layer is formed by bundling approximately 10,000 to 40,000 strands of fiber reinforced plastic (CFRP) such as glass fiber or carbon fiber, impregnating the bundle with a thermosetting resin such as epoxy, and winding the resulting fiber bundle around the outer periphery of the tank body 21.

[0013] The nozzle 22 is a metal member that connects the inside and outside of the tank body 21. In this embodiment, the nozzle 22 is provided at one end in the longitudinal direction of the tank body 21, but it may be provided at both ends. The nozzle 22 has a tubular portion 25 and a flange portion 26.

[0014] The cylindrical portion 25 is a substantially cylindrical portion that communicates between the inside and outside of the tank body 21. A portion of the cylindrical portion 25 is exposed to the outside of the tank body 21. The flange portion 26 is connected to the cylindrical portion 25 and is a flange-shaped portion that protrudes in the radial direction of the cylindrical portion 25. The flange portion 26 is housed in the tank body 21.

[0015] The inspection device 100 is a device that inspects the hydrogen tank 20 for abnormalities using images of the hydrogen tank 20 captured by an imaging device 200. The inspection device 100 is composed of a computer equipped with an input / output interface 110, a memory unit 120, and a CPU 130. The input / output interface 110, the memory unit 120, and the CPU 130 are connected to enable bidirectional communication. The memory unit 120 is composed of ROM and RAM.

[0016] The CPU 130 executes a program pre-installed in the storage unit 120 to implement the functions of the calculation unit 131 and the determination unit 132. However, some or all of the functions of these units may be implemented by a hardware circuit.

[0017] The calculation unit 131 calculates a displacement difference, which is the difference in displacement between multiple parts of the hydrogen tank 20 in the axial direction, using images acquired from the imaging device 200 via the input / output interface 110. The calculation unit 131 calculates the displacement difference by, for example, digital image correlation (DIC). More specifically, the calculation unit 131 calculates the displacement difference based on the deformation of the pattern applied to the surface of the hydrogen tank 20.

[0018] The determination unit 132 determines that there is an abnormality in the hydrogen tank 20 if the displacement difference calculated by the calculation unit 131 is equal to or greater than a predetermined threshold. The threshold is a value determined in advance experimentally and empirically, and indicates low strength quality. More specifically, the threshold is a value indicating that, in a burst test, uneven expansion in the tank body 21 will occur, making it highly likely that rupture will occur from the dome portion 24 rather than from the cylindrical portion 23. The burst test is a test in which, for example, the hydrogen tank 20 is filled with a fluid liquid to increase the internal pressure of the hydrogen tank 20, and the manner in which the hydrogen tank 20 will rupture and whether the internal pressure at the time of rupture is within a standard range are determined.

[0019] 2 is a flowchart showing an example of an inspection process. This process is a process for detecting an abnormality in the hydrogen tank 20 during a pressure test. The pressure test is a test in which a fluid is filled into the hydrogen tank 20 and a predetermined pressure is applied. The pressure test is a test in which, for example, the hydrogen tank 20 is filled with a liquid 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 standard range.

[0020] In step S100, a fluid is filled into the hydrogen tank 20 to apply a predetermined pressure. More specifically, the hydrogen tank 20 is filled with liquid until the internal pressure of the hydrogen tank 20 increases to a predetermined value.

[0021] In step S110, calculation unit 131 calculates a displacement difference, which is the difference between the amount of displacement of the first section and the amount of displacement of the second section of hydrogen tank 20, from the image captured by imaging device 200. More specifically, calculation unit 131 calculates, from the image captured by imaging device 200, the difference between the amount of displacement in the axial direction of tank body 21 from the first section of hydrogen tank 20 before step S100 to the first section of hydrogen tank 20 after step S100, and the amount of displacement in the axial direction of tank body 21 from the second section of hydrogen tank 20 before step S100 to the second section of hydrogen tank 20 after step S100. Details of the first and second sections will be described later.

[0022] FIG. 3 is a cross-sectional view of the nozzle 22 portion of the hydrogen tank 20. The first portion 27 and the second portion 28 are portions located in the dome portion 24. The first portion 27 is the portion where the tank body 21 and the cylindrical portion 25 of the nozzle 22 are in contact. More specifically, the first portion 27 is the portion of the outer surface of the tank body 21 where the opening of the tank body 21 is in contact with the base portion of the flange 26 protruding from the cylindrical portion 25. The second portion 28 is the portion where the tank body 21 and the flange 26 are in contact. More specifically, the second portion 28 is the portion of the outer surface of the tank body 21 that corresponds in the axial direction to a contact portion 29 where the inner surface of the tank body 21 is in contact with the tip portion of the flange 26.

[0023] In step S120 (see FIG. 2), the determination unit 132 determines whether the displacement difference calculated in step S110 is equal to or greater than a predetermined threshold. The threshold is, for example, a value greater than or equal to 1.5 mm and less than or equal to 3 mm. If the displacement difference is equal to or greater than the threshold, the determination unit 132 proceeds to the processing of step S130 and determines that there is an abnormality in the hydrogen tank 20. In step S130, the determination unit 132 may notify the user of the abnormality in the hydrogen tank 20 via a notification device (not shown). On the other hand, if the displacement difference is less than the threshold, the determination unit 132 proceeds to the processing of step S135 and determines that there is no abnormality in the hydrogen tank 20.

[0024] According to the inspection method for hydrogen tank 20 of this embodiment described above, if uneven expansion occurs in tank body 21 during a burst test, it is determined that there is an abnormality in hydrogen tank 20. Therefore, even if hydrogen tank 20 is not damaged, an abnormality in hydrogen tank 20 can be detected.

[0025] B. Other Embodiments: In the above-described embodiment, the calculation unit 131 calculates the displacement difference. However, the calculation unit 131 may calculate only the amount of displacement of the first unit 27 and the second unit 28 in the axial direction of the tank body 21. In this case, the determination unit 132 calculates the displacement difference using the amount of displacement calculated by the calculation unit 131 and determines whether the displacement difference is equal to or greater than a threshold value. Alternatively, the displacement difference may be calculated by a device external to the inspection device 100. In this case, the determination unit 132 determines whether the displacement difference is equal to or greater than a threshold value using the displacement difference acquired from outside via the input / output interface 110.

[0026] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0027] 10...inspection system, 20...hydrogen tank, 21...tank body, 22...mouthpiece, 23...cylindrical portion, 24...dome portion, 25...tubular portion, 26...flange portion, 27...first portion, 28...second portion, 29...contact portion, 100...inspection device, 110...input / output interface, 120...storage unit, 130...CPU, 131...calculation unit, 132...determination unit, 200...imaging device

Claims

[Claim 1] A method for inspecting a hydrogen tank having a tank body that stores hydrogen, and a mouthpiece that is provided at an end of the tank body and has a cylindrical portion and a flange portion that protrudes from the cylindrical portion in a radial direction of the cylindrical portion, comprising: filling the hydrogen tank with a fluid to apply a predetermined pressure; acquiring a displacement difference that is a difference between an amount of displacement of a first portion of the tank body that is in contact with the cylindrical portion in the axial direction of the tank body and an amount of displacement of a second portion of the tank body that is in contact with the flange portion in the axial direction; An inspection method including a step of outputting an indication that there is an abnormality in the hydrogen tank when the displacement difference is equal to or greater than a predetermined threshold value.

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