Hydrogen tank

Abstract

The purpose of the present invention is to make it possible to inspect the inclusion of foreign matter through visual observation in a liner constituting a hydrogen tank. The hydrogen tank is provided with a liner, the liner is provided with a cylindrical part and dome parts respectively arranged at two ends of the cylindrical part, each dome part is provided with a main body and a joint part jointed with the cylindrical part, the joint part of each dome part is provided with a part to which a deep color is applied, and the light transmission of the main body is higher than that of the joint part.

Description

Technical Field

[0001] The present disclosure relates to a hydrogen tank for storing hydrogen. Background Art

[0002] Patent Document 1 discloses a technique for manufacturing a lining by welding three components, namely, a dome member, a cylinder, and a dome member, at two locations.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-112256

[0004] It is conceivable that the dome member and the cylinder body are joined by laser welding, but the material constituting the dome member absorbs the energy of the laser and generates heat, so it needs to be made black. However, since it is made black, it is difficult to detect foreign matter by appearance recognition. Summary of the invention

[0005] In view of the above-mentioned problems, an object of the present disclosure is to enable inspection of foreign matter mixing in a lining constituting a hydrogen tank by visual observation.

[0006] The present application discloses a hydrogen tank, which is a hydrogen tank with a lining, wherein the lining has a cylindrical portion and a dome portion respectively arranged at both ends of the cylindrical portion, the dome portion has a main body and a joint portion connected to the cylindrical portion, the joint portion of the dome portion has a portion applied with a dark color, and the light transmittance of the main body is higher than the light transmittance of the joint portion.

[0007] The bonding portion may be provided with a thin film portion extending in an annular shape along the circumference of the bonding portion.

[0008] It can also be constructed as follows: the joining portion has a first annular portion, and a second annular portion which is arranged at a position closer to the cylindrical portion than the first annular portion and has an outer diameter smaller than that of the first annular portion, the first annular portion is provided with an inclined portion whose diameter decreases as it moves toward the second annular portion, and the cylindrical portion and the dome portion are joined at least at the inclined portion of the first annular portion.

[0009] According to the present disclosure, the light transmittance of the main body of the dome portion is higher than that of the joint portion, so that foreign matter in the lining can be inspected by visual observation. On the other hand, the dome portion and the cylindrical portion are joined at the joint portion having a dark-colored portion, so even if they are joined by laser welding, sufficient joining quality can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is an external view showing the structure of the hydrogen tank 1 .

[0011] Figure 2 It is a cross-sectional view showing the structure of the hydrogen tank 1 .

[0012] Figure 3It is a cross-sectional view of the lining 10.

[0013] Figure 4 It is an exploded cross-sectional view of the lining 10.

[0014] Figure 5 It is a diagram for explaining the joint 14 of Embodiment 1.

[0015] Figure 6 It is used to Figure 5 explain a modified example of

[0016] Figure 7 It is a diagram for explaining the joint 24 of Embodiment 2.

[0017] Figure 8 It is for Figure 7 explaining a modified example of

[0018] Figure 9 It is for Figure 8 explaining a modified example of

[0019] Explanation of reference numerals

[0020] 1…Hydrogen tank; 2…Reinforcement layer; 3…Joint; 4…On-off valve; 10…Lining; 11…Cylindrical part; 12…Dome part; 13…Main body; 14, 24…Joints; 14a, 24a…Base parts; 14b, 24b…Dark parts; 241a…First annular part; 242a…Second annular part. Detailed implementation manners

[0021] 1. Basic structure of the hydrogen tank

[0022] The present disclosure has features on the lining included in the hydrogen tank. Before explaining this feature of the lining, the basic structure of the hydrogen tank including this lining as a component is explained.

[0023] The hydrogen tank 1 is a container for storing hydrogen as fuel in a liquid state or a gas state. Diagrams for explanation are shown in Figure 1 、 Figure 2 . Figure 1 is an external view, Figure 2 and is a cross-sectional view along the axis O of the hydrogen tank 1. From these diagrams, it can be seen that in the present embodiment, the hydrogen tank 1 has a lining 10, a reinforcement layer 2, a joint 3, and an on-off valve 4. Hereinafter, each structure will be explained.

[0024] 1.1. Lining

[0025] Here, an outline of the lining 10 is shown, and the details will be explained later.

[0026] The liner 10 is a hollow component that divides the internal space of the hydrogen tank 1 and is cylindrical in this embodiment. The liner 10 has a cylindrical portion 11 that is cylindrical with a substantially constant diameter, and dome-shaped dome portions 12 that are arranged to cover the openings at both ends of the cylindrical portion 11 respectively.

[0027] The side of the dome portion 12 opposite to the cylindrical portion 11 is dome-shaped, thereby reducing the diameter, and a joint 3 is arranged at the opening 12a formed at the reduced end.

[0028] 1.2. Reinforcement layer

[0029] For the reinforcement layer 2, it extends over multiple layers of laminated fibers, and the fibers are impregnated with a cured resin. The layer formed by the fibers is formed by winding fiber bundles around the outer periphery of the liner 10 in multiple layers to a specified thickness. The thickness of the reinforcement layer 2 and the number of windings of the fiber bundles are determined according to the required strength and are not particularly limited, but are about 10 mm to 30 mm.

[0030] <Fiber bundle>

[0031] The fiber bundles of the reinforcement layer 13 use carbon fibers, for example. The fiber bundles are ribbons in which carbon fibers are bundled and have a specified cross-sectional shape (for example, a rectangular cross-section). Specifically, although not particularly limited, the cross-sectional shape can be a rectangle with a width of 6 mm to 20 mm and a thickness of about 0.1 mm to 0.3 mm. The amount of carbon fibers contained in the fiber bundles is not particularly limited either, but for example, it can be composed of about 36000 carbon fibers.

[0032] <Impregnated resin>

[0033] The resin impregnated and cured in the fibers (fiber bundles) in the reinforcement layer 2 is not particularly limited as long as it can improve the strength of the fibers thereby. Among them, for example, thermosetting resins that are cured by heat can be cited. Specifically, there are epoxy resins, unsaturated polyester resins, etc. that contain amine-based or anhydride-based curing accelerators and rubber-based reinforcing agents. In addition, a resin composition that is mainly composed of an epoxy resin and cured by mixing a curing agent therein can also be cited. Thus, by allowing the resin composition as the mixture to reach and penetrate the fiber layer during the period from the mixing of the main agent and the curing agent to the curing, it is automatically cured.

[0034] <Protective layer>

[0035] A protective layer can also be arranged on the outer periphery of the reinforcement layer as needed. When setting it, for example, glass fibers are wound and impregnated with resin. It can be considered that the impregnated resin is the same as that of the reinforcement layer 12. Thus, impact resistance can be imparted to the hydrogen tank 1.

[0036] The thickness of the protective layer is not particularly limited, but can be about 1.0 mm to 1.5 mm.

[0037] 1.3. Joint

[0038] The joint 3 is a component respectively installed in two openings 12a of the lining 10, and is respectively arranged at both ends in the direction of the axis O of the lining 10. The joint 3 functions as an opening for connecting the inside and outside of the hydrogen tank 1, and an opening and closing valve 4 is installed on one of them. Therefore, a hole with a circular cross-section for arranging the opening and closing valve 4 is provided in the joint 3. An internal thread corresponding to the external thread of the opening and closing valve 4 is provided on the inner surface of the hole. The opening and closing valve 4 is fixed to the joint 3 by combining the external thread of the opening and closing valve 4 with the internal thread. In addition, on the inner surface of the hole, a sealing surface as a smooth surface is provided at a position closer to the inside of the tank (high-pressure side) than the internal thread. A sealing member provided on the outer periphery of the opening and closing valve 4 is in contact with this sealing surface to perform airtightness (sealing) inside the hydrogen tank 1.

[0039] The components constituting the joint 3 only need to have the required strength and are not particularly limited, but stainless steel, aluminum, etc. can be cited.

[0040] 1.4. Opening and closing valve

[0041] The opening and closing valve 4 is held in the hole of the joint 3 so as to straddle the inside and outside of the hydrogen tank 1. The opening and closing valve 4 is arranged in one of the two joints 3 provided at both ends in the long side direction of the hydrogen tank 1. In addition, a bolt 3a is arranged and sealed in the other joint 3.

[0042] The opening and closing valve 4 has a shaft portion arranged inside the hole of the joint 3, and an external thread combined with the internal thread of the joint 3 is provided on the outer peripheral surface of the shaft portion. Thus, the opening and closing valve 4 is fixed to the hole of the joint 3. In addition, a sealing member (not shown) is arranged on the outer peripheral surface of the opening and closing valve 4, and this sealing member is arranged in contact with the sealing surface on the inner surface of the hole of the joint 3 to perform airtightness (sealing).

[0043] The opening and closing valve 4 is a valve that switches to allow or restrict the extraction of hydrogen from the hydrogen tank 1.

[0044] The specific implementation manner of the opening and closing valve is not particularly limited, and a known opening and closing valve can be applied.

[0045] 2. Lining

[0046] Hereinafter, the lining will be described in detail. Figure 3 is a view showing the lining 10 from the Figure 2 same perspective. In addition, in Figure 4In the figure, the cylindrical part 11 and the dome part 12 are separated to show the liner 10. For the liner 10, the cylindrical part 11 and the dome part 12 are prepared separately, and the dome part 12 is joined (laser welded) to the entire circumference of the cylindrical part 11 so as to cover the respective openings at the end of the cylindrical part 11 ( Figure 3 The dotted line W is the joining part). Therefore, in the present embodiment, in the part of the dome part 12 that is joined to the cylindrical part 11, the joining parts of the respective embodiments described later are provided.

[0047] 2.1. Embodiment 1

[0048] 2.1.1. Cylindrical part

[0049] The cylindrical part 11 is the main part of the liner 10 where hydrogen is stored inside, and is a cylindrical member with a substantially constant diameter.

[0050] The material constituting the cylindrical part 11 is not particularly limited as long as it can be joined to the dome part 12 by laser welding. For example, a material composed of three layers with polyamide resin laminated on both sides of an ethylene vinyl alcohol copolymer resin can be cited.

[0051] The thickness of the cylindrical part 11 is not particularly limited, but typically it is 0.5 mm to 3.0 mm.

[0052] Such a cylindrical part 11 can be formed by extrusion molding, for example.

[0053] 2.1.2. Dome part

[0054] The dome part 12 is a member that is respectively disposed at both ends of the opening of the cylindrical part 11, is disposed so as to cover the opening, and is joined to the entire circumference of the cylindrical part 11. The diameter of the side of the dome part 12 opposite to the side joined to the cylindrical part 11 is reduced, and an opening 12a is formed at the reduced end. A joint 3 is disposed in the opening 12a.

[0055] Here, the material constituting the dome part 12 is not particularly limited as long as it can be joined to the cylindrical part 11 by laser welding. For example, it can be formed of polyamide resin and can be manufactured by injection molding.

[0056] As described above, the dome part 12 has a joining part 14 that is the part joined to the cylindrical part 11. That is, the dome part 12 has a main body 13 that is the main part of the dome part 12 (the part forming the part other than the joining part 14), and a joining part 14 disposed at the end on the side of the cylindrical part 11 in the main body 13.

[0057] In Figure 5 it shows in Figure 3A view showing an enlarged end portion of the main body 13 and a continuous joint portion 14, which is denoted by I in the figure. In addition, Figure 5 The cross-sections of the figures shown below are shown, but hatching is omitted for ease of viewing.

[0058] In the present embodiment, the joint portion 14 has a base portion 14a and a dark portion 14b.

[0059] The base portion 14a is a portion provided in an annular shape along the end face of the main body 13 and is integrally formed continuously with the main body 13. Therefore, the base portion 14a is formed of the same material as the main body 13.

[0060] In the present embodiment, the inner diameter of the base portion 14a is coplanar with the main body 13, there is no step therebetween, and the outer diameter is smaller than the main body 13. Thus, a main body 13 and a step 13a are formed.

[0061] The outer diameter of the base portion 14a is not particularly limited, but is preferably about the same as or slightly smaller than the inner diameter of the cylindrical portion 11. Also, the depth of the step 13a is not particularly limited, but is preferably about the same as the wall thickness of the cylindrical portion 11. Thus, when the cylindrical portion 11 is inserted into the step 13a, the outer diameter of the main body 13 and the outer diameter of the cylindrical portion 11 are substantially coplanar.

[0062] The dark portion 14b is a layer with a darker color provided along the outer peripheral surface of the base portion 14a. The meaning of "darker color" will be described later.

[0063] The thickness of the dark portion 14b is not particularly limited, but as long as it is a thickness capable of absorbing laser energy to generate heat and properly welding, it is typically 10 μm or more and 100 μm or less.

[0064] Regarding the darker color in the dark portion 14b, it is considered as follows.

[0065] It is configured such that when comparing the base portion 14a and the dark portion 14b, the light transmittance (transparency) of the base portion 14a is higher than that of the dark portion 14b. The light transmittance can be, for example, compared by comparing the total light transmittance. This is the ratio of the amount of light passing through an object when the amount of light passing through space without an object is set to 100%.

[0066] Thus, for the base portion 14a, light easily passes through, and foreign matters in the lining can be inspected by visual observation, so that expensive devices such as X-rays and destructive inspections can be omitted or reduced.

[0067] In addition, since inspection can be performed in a non-destructive manner, all product inspections can be carried out. Since the light transmittance is good during inspection, if a light source is used to transmit light, the inspection becomes easier.

[0068] On the other hand, the cylindrical portion 11 is inserted in such a manner that the inner peripheral surface at its end overlaps with the outer peripheral surface (i.e., the dark portion 14b) of the joint portion 14 of the dome portion 12. And as indicated by the arrow L in Figure 5 , laser light is irradiated onto the dark portion 14b from the outside. At this time, for the dark portion 14b, light is not easily transmitted. Therefore, if laser light is irradiated onto the dark portion 14b, it is easy to absorb the laser energy and generate heat through the dark portion 14b, causing the surrounding resin to melt and enabling efficient cladding.

[0069] Thus, according to the present embodiment, it is possible to achieve both ease of inspection and good-quality welding.

[0070] However, in order to make this effect more significant, it is preferable that the base portion 14a is a light color such as transparent or milky white (a color with a lower lightness, for example, 7 or more in the range of 0 to 10 in the Munsell color system). Transparent means that in the property of a substance through which light passes, the light transmittance is high, and the degree to which an object existing on the opposite side can be seen through the substance. Thereby, the ease of visual inspection can be improved. In the case of being opaque, by irradiating light from the back side, the visual inspection can be made easier.

[0071] On the other hand, for the dark portion 14b, in order to make the effect more significant, it is preferable that it is a color with a lower lightness, and more preferably black. For example, it is 5 or less in the range of 0 to 10 in the Munsell color system.

[0072] As a specific dark portion 14b, for example, it is formed by coating the base portion 14a with a material in which a black pigment such as carbon black is added to a resin (such as a polyamide resin).

[0073] In Figure 6 , a diagram for explaining a modification of the above-described Embodiment 1 is shown. Figure 6 It is a diagram based on the same perspective as Figure 5 . In this example, instead of the above-described dark portion 14b, a dark portion 14'b is used.

[0074] It can be considered that other parts are the same as above, so the same reference numerals are assigned and the description is omitted.

[0075] The dark portion 14'b is arranged to wind a ring-shaped member with a thin thickness around the outer periphery of the base portion 14a. It can be considered that the color of the ring-shaped member constituting the dark portion 14'b is the same as that of the above-described dark portion 14b.

[0076] For the ring-shaped member, for example, a strip-shaped material in which a black pigment such as carbon black is added to a resin (such as a polyamide resin) can be formed and wound around the base portion 14a.

[0077] By providing such a dark color portion 14 ′ b , the same effect as described above is also achieved.

[0078] 2.2. Implementation Method 2

[0079] exist Figures 7 - 9 , a diagram illustrating implementation example 2 is shown. Figures 7 - 9 All are based on Figure 5 The same perspective image, Figure 8 is relative to Figure 7 A variation of Figure 9 is relative to Figure 8 Another variation of .

[0080] In Embodiment 2, the shape of the joining portion is different from that of Embodiment 1, but other portions can be considered to be the same as those of Embodiment 1, and thus description thereof will be omitted here.

[0081] like Figure 7 As shown, in this embodiment, the engaging portion 24 has a base portion 24a and a dark-colored portion 24b.

[0082] The base portion 24a is a portion provided in an annular shape along the end surface of the main body 13, and is formed continuously and integrally with the main body 13. Therefore, the base portion 24a is formed of the same material as the main body 13.

[0083] In the present embodiment, the base portion 24a includes a first annular portion 241a disposed at a position on the main body 13 side, and a second annular portion 242a disposed on the opposite side of the first annular portion 241a from the main body 13 side.

[0084] The first annular portion 241 a and the second annular portion 242 a are both formed so that their inner diameters are flush with the main body 13 and there is no step between them and the main body 13 .

[0085] In contrast, regarding the outer diameter, the first annular portion 241a has an inclined surface in such a manner that the outer diameter is the same as that of the main body 13 on the main body 13 side, but the outer diameter decreases as it approaches the second annular portion 242a. Moreover, the outer diameter is the same as that of the second annular portion 242a on the second annular portion 242a side of the first annular portion 241a. Preferably, the inclination angle of the inclined surface is greater than 15 degrees and less than 75 degrees relative to the axis O. More preferably, it is greater than 30 degrees and less than 60 degrees. If the inclination angle is greater than 75 degrees, the force required for the engagement of the cylindrical portion 11 and the dome portion 12 tends to become too large. On the other hand, if the inclination angle is less than 15 degrees, the length used for pressing in during the engagement becomes longer, and there is a tendency for the processing time to be extended and the amount of material to increase.

[0086] On the other hand, the outer diameter of the second annular portion 242a is not particularly limited, but is preferably about the same as or slightly smaller than the inner diameter of the cylindrical portion 11. Moreover, the difference between the outer diameter of the second annular portion 242a and the outer diameter of the main body 13 is not particularly limited, but is preferably about the same as the wall thickness of the cylindrical portion 11. Thus, when the cylindrical portion 11 is inserted into the joint portion 24, the outer diameter of the main body 13 and the outer diameter of the cylindrical portion 11 are substantially coplanar.

[0087] In the present embodiment, the dark portion 24b is a layer with a darker color provided along the outer peripheral surface of the base portion 24a. It is considered that the shape and effect of the dark portion 24b are the same as those of the dark portion 14b described above.

[0088] According to such a joint portion 24, in addition to the effects described in the above Embodiment 1, the fitting of the cylindrical portion 11 and the dome portion 12 can be firmly performed. For example, in the case where there is no first annular portion, it becomes the embodiment described in Embodiment 1 Figure 5 of that kind, but at the inner corner portion of the step 13a, a circular arc-shaped portion (R shape) is formed to prevent stress concentration. Due to the presence of this R shape, as Figure 5 shown, a gap is formed at the end face where the main body 13 and the cylindrical portion 11 face each other.

[0089] In contrast, according to Embodiment 2, this gap can be eliminated to fit the cylindrical portion 11 and the dome portion 12, so that an increase in strength during deformation and prevention of the impregnating resin from entering the reinforcing layer 2 can be achieved. In addition, a load can be applied in the direction along the axis O as indicated by the arrow F during joining, so that it is easy to control the surface pressure when cladding the inclined surface, and stabilization of the cladding quality can be achieved. In addition, if there is a gap, the lining becomes thinner at this portion, so by eliminating the gap, the hydrogen permeation amount can also be reduced.

[0090] Figure 8 The example shown is Figure 7 a modified example of the example shown, and is an example in which the dark portion 24'b is arranged only in the first annular portion 241a. From the viewpoint of joint strength, it is preferable to arrange the dark portion 24b in both the first annular portion 241a and the second annular portion 242a for joining as Figure 7 shown, but if the strength can be sufficiently ensured, from the viewpoint of productivity, the dark portion 24'b can also be arranged only in the first annular portion 241a like this.

[0091] Figure 9 The example shown is Figure 8 a modified example of the example shown. In Figure 9In the example shown, it is an example where the end portion of the cylindrical portion 11 is not subjected to end processing along the inclination of the first annular portion 241a. Even in such an embodiment, the above-described effects are achieved. According to this example, since end processing of the cylindrical portion 11 is not required, the number of processes can be reduced.

Claims

1. A hydrogen tank having a lining, wherein: The lining has: a cylindrical portion; and The dome parts are respectively arranged at both ends of the cylindrical part. The dome portion has a main body and a joint portion joined to the cylindrical portion. The joint portion of the dome portion includes a dark-colored portion, and the main body has a higher light transmittance than the joint portion.

2. The hydrogen tank according to claim 1, wherein: The joining portion includes a thin film portion extending in an annular shape from the dark-colored portion along its circumference. The thin film portion is joined to the cylindrical portion so as to be in contact with the cylindrical portion.

3. The hydrogen tank according to claim 1 or 2, wherein: The joint portion has: a first annular portion; and The second annular portion is disposed closer to the cylindrical portion than the first annular portion and has an outer diameter smaller than that of the first annular portion. The first annular portion is provided with an inclined portion whose diameter decreases toward the second annular portion. The cylindrical portion and the dome portion are joined at least at the inclined portion of the first annular portion.

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