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 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 to the hydrogen tank, a step of acquiring a determination displacement amount that is a largest displacement amount of the dome portions in a radial direction of the hydrogen tank or a largest local maximum value among local maximum values at which the displacement amount changes from an increase to a decrease, and a step of outputting that there is an abnormality in the hydrogen tank when the determination displacement amount 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 cylindrical portion and two dome portions provided on both ends of the cylindrical portion, the method including the steps of filling the hydrogen tank with a fluid and applying a predetermined pressure, obtaining a judged displacement amount that is the largest displacement amount of the dome portions in the radial direction of the hydrogen tank or the largest maximum value among the maximum values ​​where the displacement amount changes from an increase to a decrease, and outputting an indication that there is an abnormality in the hydrogen tank if the judged displacement amount 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. 10 is a diagram showing an example of the displacement amount of the tank body. 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 may be provided at both ends.

[0014] 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.

[0015] 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.

[0016] The calculation unit 131 calculates the amount of displacement, which is the magnitude of displacement at each position of the dome section 24 in the radial direction of the hydrogen tank 20, using images acquired from the imaging device 200 via the input / output interface 110. The calculation unit 131 calculates the amount of displacement by, for example, digital image correlation (DIC). More specifically, the calculation unit 131 calculates the amount of displacement based on the deformation of the pattern applied to the surface of the hydrogen tank 20.

[0017] The determination unit 132 determines that there is an abnormality in the hydrogen tank 20 if the displacement 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 there is a high possibility that the tank body 21 will burst from the dome portion 24 at an internal pressure lower than the target internal pressure in a burst test. 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 burst and whether the internal pressure at the time of rupture is within a standard range are determined.

[0018] 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.

[0019] 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.

[0020] In step S110, calculation unit 131 calculates a determinable displacement amount for dome portion 24 from the image captured by imaging device 200. More specifically, calculation unit 131 calculates the displacement amount for each position in the radial direction of dome portion 24 of hydrogen tank 20 from before step S100 to after step S100 from the image captured by imaging device 200, and determines the determinable displacement amount. In this embodiment, the determinable displacement amount is the largest maximum value among the maximum values ​​at which the displacement amount changes from increasing to decreasing in a graph showing the displacement amount for dome portion 24 with the horizontal axis representing position in the axial direction and the vertical axis representing the displacement amount.

[0021] FIG. 3 is a diagram showing an example of the displacement amount of the tank body 21. In the graph shown in FIG. 3, the horizontal axis represents the position in the axial direction of the tank body 21. The vertical axis represents the displacement amount. Regression line G1 represents the displacement amount when the tank body 21 is normal. Regression lines G2, G3, and G4 all represent the displacement amount when there is an abnormality in the tank body 21. The determined displacement amount for regression line G1 is displacement amount d1, the determined displacement amount for regression line G2 is displacement amount d2, the determined displacement amount for regression line G3 is displacement amount d3, and the determined displacement amount for regression line G4 is displacement amount d4. The displacement amount d1 is a value less than the threshold value dth, and the displacement amounts d2, d3, and d4 are all values ​​equal to or greater than the threshold value dth.

[0022] In step S120 (see FIG. 2), the determination unit 132 determines whether the determined displacement amount calculated in step S110 is equal to or greater than a predetermined threshold value dth. The threshold value dth is a value equal to or less than the smallest displacement amount in the radial direction of the cylindrical portion 23, and is, for example, a value between 0.4 mm and 0.6 mm. If the determined displacement amount is equal to or greater than the threshold value dth, 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 hydrogen tank 20 of the abnormality via a notification device (not shown). On the other hand, if the determined displacement amount is less than the threshold value dth, the determination unit 132 proceeds to the processing of step S135 and determines that there is no abnormality in the hydrogen tank 20.

[0023] According to the inspection method for hydrogen tank 20 of this embodiment described above, if the expansion of dome portion 24 is equal to or greater than a threshold value during a pressure test, it is determined that there is an abnormality in hydrogen tank 20. Therefore, even if there is no damage to hydrogen tank 20, an abnormality in hydrogen tank 20 can be detected.

[0024] B. Other Embodiments: In the above-described embodiment, the determination amount of displacement is the largest maximum value in a graph showing the amount of displacement in the dome portion 24 as axial position on the horizontal axis and the amount of displacement on the vertical axis. However, the determination amount of displacement is not limited to this, and may simply be the largest value among the amounts of displacement in the dome portion 24.

[0025] 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]

[0026] 10...inspection system, 20...hydrogen tank, 21...tank body, 22...mouthpiece, 23...cylindrical portion, 24...dome 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] 1. A method for inspecting a hydrogen tank having a cylindrical portion and two dome portions provided at both ends of the cylindrical portion, comprising: filling the hydrogen tank with a fluid to apply a predetermined pressure; acquiring a determination displacement amount that is the largest displacement amount of the dome portion in the radial direction of the hydrogen tank or the largest maximum value among the maximum values ​​at which the displacement amount changes from an increase to a decrease; An inspection method including a step of outputting an indication that there is an abnormality in the hydrogen tank when the determined displacement amount is equal to or greater than a predetermined threshold value.

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