Method for manufacturing a high-pressure tank

Abstract

In the manufacturing method of the high-pressure tank of the present application, as the liner, a liner is prepared, which has: a liner main body having a neck portion continuous with a cylindrical portion in which a receiving space is formed and extending toward an opening portion; and a metal-made reinforcement body disposed in the neck portion. A reinforcing fiber base material is formed on an outer peripheral surface of the liner by winding the reinforcing fiber on the outer peripheral surface of the liner. The liner on which the reinforcing fiber base material is wound is disposed in a molding die, an internal pressure is applied to the receiving space, and a base resin is injected between the molding die and the liner, whereby the base resin is impregnated in the reinforcing fiber base material to form a reinforcement layer.

Description

Technical Field

[0001] This invention relates to a method for manufacturing high-pressure tanks. Background Technology

[0002] For example, high-pressure tanks for storing fuel gases are used in natural gas vehicles or fuel cell vehicles. Such high-pressure tanks have a lining that contains a fluid as a high-pressure gas, and a reinforcing layer made of fiber-reinforced resin that covers the outer periphery of the lining.

[0003] When manufacturing a high-pressure tank, firstly, a resin liner is prepared. The liner has a cylindrical body portion forming a storage space for high-pressure gas, and a neck portion continuously formed from the end of the cylindrical body portion. For this prepared liner, a reinforcing layer made of fiber-reinforced resin is formed on the outer peripheral surface of the cylindrical body portion and the neck portion (for example, see Japanese Patent Application Laid-Open No. 2020-60265).

[0004] Here, for example, when forming the reinforcing layer shown in Japanese Patent Application Laid-Open No. 2020-60265, it is assumed that after forming a reinforcing fiber substrate on the outer peripheral surface of the lining by winding reinforcing fibers around the outer peripheral surface of the lining, the matrix resin is impregnated into the reinforcing fiber substrate.

[0005] In this case, a liner wound with a reinforcing fiber substrate is placed in a molding die, internal pressure is applied to the liner's storage space, and a matrix resin is injected between the molding die and the liner. At this time, the circumferential stress acts on the cylindrical portion of the liner in a manner that expands circumferentially in the cylindrical portion, so the reinforcing fibers wound around the cylindrical portion of the liner are less likely to deviate from their winding direction.

[0006] However, the boundary between the cylinder and the neck is concave, causing circumferential stress to act in a way that narrows circumferentially at the boundary. This circumferential stress slightly reduces the diameter of the boundary, making it easy for the reinforcing fibers wrapped around it to loosen. In this state, even impregnating the reinforcing fibers (reinforcing fiber substrate) with matrix resin cannot guarantee the mechanical strength of the boundary. Summary of the Invention

[0007] The present invention was made in view of the fact that it provides a method for manufacturing a high-pressure vessel in which a matrix resin is impregnated while suppressing the loosening of reinforcing fibers wrapped around the boundary portion, thereby achieving stable strength.

[0008] In view of the above-mentioned problems, the manufacturing method of the high-pressure tank according to the present invention comprises a resin liner having a reservoir space for containing fluid and an opening at least at one end, and a reinforcing layer made of fiber-reinforced resin covering the outer peripheral surface of the liner, characterized in that the manufacturing method of the high-pressure tank includes: a step of preparing a liner having a liner body and a metal reinforcing body, the liner body having a neck that is continuous with a cylindrical portion having the reservoir space and extends toward the opening, the metal reinforcing body being disposed at least at the boundary between the neck and the cylindrical portion; a step of forming a reinforcing fiber substrate on the outer peripheral surface of the liner by winding reinforcing fibers around the outer peripheral surface of the liner; and a step of placing the liner with the reinforcing fiber substrate wound on a molding die, applying internal pressure to the reservoir space, and injecting a matrix resin between the molding die and the liner, thereby impregnating the reinforcing fiber substrate with the matrix resin to form the reinforcing layer.

[0009] According to the present invention, if internal pressure is applied to the receiving space formed by the liner during the formation of the reinforcing layer, the circumferential stress acts on the boundary portion where the neck of the liner meets the cylinder portion in a concave shape, thus the stress decreases in the circumferential direction. However, in the present invention, a metallic reinforcing body is provided at least at the boundary portion, thereby suppressing circumferential deformation of the boundary portion. This allows the matrix resin to impregnate the reinforcing fiber substrate while suppressing loosening of the reinforcing fibers wound around the boundary portion. As a result, a high-pressure vessel with stable strength can be obtained.

[0010] As a more preferred embodiment, in the process of preparing the lining, the reinforcing body and the lining body are integrally molded together.

[0011] According to this design, the reinforcing body and the lining body are integrally molded together, thus constraining the lining body to the reinforcing body. Therefore, even if circumferential stress acts on the boundary portion in a manner that decreases in the circumferential direction, the shape of the boundary portion can be maintained.

[0012] In a more preferred embodiment, the high-pressure tank is provided with a connecting member that covers the opening, an insertion portion that is inserted into the opening is formed in the connecting member, a sealing member that contacts the inner circumferential surface of the liner is provided in the insertion portion, and the reinforcing body extends to a position opposite to the sealing member.

[0013] Based on this configuration, the reinforcing body extends to a position opposite the sealing component, so that when using the high-pressure tank, even when fluid is being filled into and discharged into the storage space, the sealing performance based on the sealing component can be ensured by the reinforcing body.

[0014] According to the present invention, by impregnating the reinforcing fiber substrate with a matrix resin while suppressing the loosening of the reinforcing fibers wrapped around the boundary portion, stable strength can be obtained.

[0015] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements. Attached Figure Description

[0016] Figure 1 This is a perspective view showing the structure of a tank unit having a high-pressure tank manufactured by the manufacturing method according to this embodiment.

[0017] Figure 2 It is along Figure 1 A cross-sectional view of the high-pressure tank of line II-II.

[0018] Figure 3 yes Figure 2 An enlarged sectional view of the main parts of the high-pressure tank on the bracket side is shown.

[0019] Figure 4 It is used for in Figure 3 A cross-sectional view illustrating the process of preparing the lining in the manufacturing method of the high-pressure tank shown.

[0020] Figure 5 It is used for in Figure 1 The diagram illustrates the process of forming a reinforced fiber substrate in the manufacturing method of the high-pressure tank.

[0021] Figure 6 It is used for in Figure 3 The diagram illustrates the state of the reinforced fiber substrate formed during the manufacturing process of the high-pressure tank.

[0022] Figure 7 It is used for in Figure 1 A cross-sectional view illustrating the process of forming a reinforcing layer in the manufacturing method of the high-pressure tank shown.

[0023] Figure 8 This diagram illustrates the circumferential stress acting during the formation of the reinforcing layer in the manufacturing method of the high-pressure tank according to this embodiment. Detailed Implementation

[0024] 1. Regarding the high-pressure tank 10

[0025] First, let's refer to... Figures 1-3 The implementation of the tank unit 1, which includes the high-pressure tank 10, will be described below. Figure 1 and Figure 2As shown, the tank unit 1 involved in this embodiment includes a plurality of high-pressure tanks 10 and a pair of connecting parts 30, 30 connected to both ends of the high-pressure tanks 10.

[0026] The high-pressure tank 10 is a tank for filling high-pressure hydrogen in fuel cell vehicles. The gas that can be filled into the high-pressure tank 10 is not limited to high-pressure hydrogen. It can be filled with various compressed gases such as CNG (compressed natural gas), various liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), other gases (fluids), or temporarily filled with liquids or other fluids for pressure testing purposes.

[0027] The high-pressure tank 10 includes: a liner 11 forming a hydrogen storage space S and having openings 13 on both sides; and a reinforcing layer 12 layered on the liner 11 to cover the outer peripheral surface 11a of the liner 11. The liner 11 is composed of a liner body 11A and a metal reinforcing body 40, wherein the liner body 11A is made of a resin material with gas barrier properties. The reinforcing layer 12 is made of fiber-reinforced resin.

[0028] The liner body 11A has a cylindrical portion 14 with the aforementioned storage space S, and a pair of necks 15, 15 that are continuous with the end of the cylindrical portion 14 and have an opening 13. In this embodiment, the necks 15, 15 are formed on both sides of the liner 11, but the high-pressure canister 10 may also be a bottle-shaped structure with a neck 15 formed only on one side.

[0029] In this embodiment, the cylindrical portion 14 includes a cylindrical body 14a, which is an example of a cylindrical shape, and a shoulder 14b whose inner and outer diameters decrease as it enters the end of the cylindrical portion 14 from the body 14a. The shoulder 14b is a frustoconical cylindrical portion, and a neck 15 is formed continuously with the shoulder 14b. The neck 15 is a cylindrical portion that extends toward the opening 13 in a direction along the axis CL of the high-pressure tank 10. Therefore, in appearance, the boundary portion 16 between the cylindrical portion 14 (shoulder 14b) and the neck 15 has a recessed shape.

[0030] In this embodiment, a metal reinforcement 40 is provided at the boundary portion 16 between the neck 15 and the cylindrical portion 14. To ensure the sealing performance described later, the reinforcement 40 may also extend to a portion of the neck 15.

[0031] In this embodiment, an annular connector 20 is mounted on the outer peripheral surface 12b of the reinforcing layer 12 covering the neck 15. Multiple protrusions are formed on the inner peripheral surface 22 of the connector 20, and the reinforcing layer 12 is configured to engage with the inner peripheral surface 22 (specifically, with the protrusions interlocking). This allows the connector 20 to be locked to the reinforcing layer 12. An external thread is formed on the outer peripheral surface 21 of the connector 20, which can be threaded into the internal thread of the inner wall surface 34 of the connecting member 30, described later.

[0032] In this embodiment, the resin constituting the lining body 11A is preferably a resin with good gas barrier properties. Examples of such resins include polypropylene resins, nylon resins (e.g., 6-nylon resin or 6,6-nylon resin), polycarbonate resins, acrylic resins, ABS resins, polyamide resins, polyethylene resins, ethylene-vinyl alcohol copolymer resins (EVOH), or polyester resins, etc., which are thermoplastic resins.

[0033] The reinforcing layer 12 has a thermoplastic resin or a thermosetting resin impregnated on the reinforcing fiber (reinforcing fiber substrate) as the matrix resin. In this embodiment, the reinforcing fiber is a fiber bundle. As the reinforcing fiber, glass fiber, aramid fiber, boron fiber, and carbon fiber can be used, and carbon fiber is preferred, especially from the viewpoints of lightweight and mechanical strength. As the matrix resin, a thermosetting resin is preferred. The thermosetting resin is a phenolic resin, melamine resin, urea resin, or epoxy resin. From the viewpoints of mechanical strength, an epoxy resin precursor is preferred. The epoxy resin is an epoxy resin that has fluidity in the uncured state and forms a strong cross-linked structure after thermosetting.

[0034] The reinforcing layer 12 is formed by winding reinforcing fibers (reinforcing fiber bundles) impregnated with matrix resin onto the outer peripheral surface 11a of the lining 11 using either filament winding or sheet winding methods. The reinforcing layer 12 can be a spirally wound layer in which the fiber bundles are wound at an angle relative to the axis CL of the high-pressure tank 10. For example, it can be a layer woven in which the fiber bundles are wound at an angle relative to the axis CL of the high-pressure tank 10 (knitting machine winding). These layers can also be combined and stacked.

[0035] A pair of connecting parts 30, 30 are made of metals such as aluminum and steel, and consist of a bracket 30A and a manifold 30B. The bracket 30A is used to bind multiple high-pressure tanks 10, 10, ... together and install them on the vehicle.

[0036] Manifold 30B is a component that forms a gas flow path for introducing hydrogen into and releasing hydrogen from the receiving space S of the high-pressure tank 10. For example... Figure 2As shown, the main difference between bracket 30A and manifold 30B lies in the presence or absence of a gas flow path; therefore, refer to... Figure 3 The structure of the manifold 30B, which serves as the connecting component 30, will be described.

[0037] The manifold 30B is formed as an opening 13 covering the end of the high-pressure tank 10 in the axial direction CL. The manifold 30B has an insertion part 31 and a cap part 32. The cap part 32 is the part that is screwed onto the outer peripheral surface 21 of the connector 20 and covers the end face of the high-pressure tank 10. The insertion part 31 is formed in the center of the cap part 32.

[0038] The insertion portion 31 is a plug-like portion that is inserted into the neck 15 from the opening 13 along the inner peripheral surface 15a of the neck 15. An annular groove 35 is formed on the outer peripheral surface 31a of the insertion portion 31 along its circumference, and annular sealing members 61 and 62 are disposed in the annular groove 35 to seal the storage space S. Specifically, the sealing members 61 and 62 contact the inner peripheral surface 11b of the liner 11 (specifically, the inner peripheral surface 15a of the neck 15), and abut against the inner peripheral surface 11b in a slightly elastically deformable radial state to ensure the sealing within the storage space S. The sealing members 61 and 62 are made of an elastic material such as a gas-barrier resin or rubber.

[0039] In this embodiment, the reinforcing body 40 is cylindrical and serves as a component that restricts radial deformation of the inner circumferential surface 15a of the neck 15. The reinforcing body 40 is disposed at the boundary portion 16 between the neck 15 and the cylindrical portion 14 of the liner body 11A. The reinforcing body 40 at least restricts radial deformation of the boundary portion 16 and is formed to surround the outer circumferential surface 15d of the neck 15. In this embodiment, the reinforcing body 40 is integrally formed with the liner body 11A.

[0040] Furthermore, in this embodiment, the reinforcing member 40 extends around the outer peripheral surface 15d of the liner 11 to a position opposite to the sealing members 61 and 62. Since the reinforcing member 40 extends to a position opposite to the sealing members 61 and 62, when the high-pressure tank 10 is in use, even when fluid is filled into and discharged into the storage space S, the sealing performance based on the sealing members 61 and 62 can be ensured by the reinforcing member 40.

[0041] The material of the reinforcement 40 is stainless steel, aluminum or other metal materials. As long as it can limit the radial expansion of the inner circumferential surface 15a of the neck 15, the material is not particularly limited.

[0042] Here, "radial deformation of the inner circumferential surface 15a of the neck 15" is the deformation caused by circumferential stress in the neck 15 due to the pressure of hydrogen gas, and is the radial expansion of the lining 11 forming the neck 15 (more specifically, the portion of the lining 11 that abuts against the sealing members 61, 62).

[0043] Furthermore, the inner circumferential surface (opposing surface) of the reinforcing body 40 abuts against the outer circumferential surface 15d of the neck 15. In this embodiment, the reinforcing body 40 extends from the end face of the high-pressure tank 10 to a portion of the shoulder 14b of the cylindrical body portion 14. The end portion on the opening 13 side of the two ends of the reinforcing body 40 has a shape that extends radially toward the reinforcing body 40, while the end portion on the cylindrical body portion 14 side is formed along the shape of the boundary portion 16. As a result, the reinforcing body 40 can easily engage with the reinforcing layer 12, thereby preventing the reinforcing body 40 from falling off in the direction along the axis CL.

[0044] 2. Manufacturing method of high-pressure tank

[0045] The following is a reference. Figures 4-8 The manufacturing method of the high-pressure tank 10 of this embodiment will be described.

[0046] (Preparing the lining 11)

[0047] First, such as Figure 4 As shown, a liner 11 is prepared, comprising a resin liner body 11A and a metal reinforcing member 40. In this embodiment, the reinforcing member 40 is disposed in an injection molding machine (not shown), and the liner body 11A is integrally molded together with the reinforcing member 40. When molding the liner body 11A, it is also possible to manufacture the liner body 11A by joining the two segments after molding the liner body 11A into two separate parts, wherein the two segments are divided at a dividing surface orthogonal to the axis CL and located at the center of the liner body 11A. Alternatively, the liner body 11A can be disposed at the boundary portion 16 between the neck 15 and the cylindrical portion 14 after molding.

[0048] (Process for forming reinforced fiber substrate)

[0049] like Figure 5 and Figure 6As shown, a reinforcing fiber substrate 12A is formed on the outer peripheral surface 11a of the lining 11 by winding reinforcing fibers 12a around it. This forms a preform 10A. Continuous reinforcing fibers 12a are sequentially drawn from multiple spools 82, 82 of a braiding machine (knitting machine) 80, and the reinforcing fibers 12a are braided around the outer peripheral surface of a neck 15, forming the reinforcing fiber substrate 12A from the neck 15 on one side of the lining 11 to the bobbin portion 14 and the neck 15 on the other side. This method can be repeated to form the reinforcing fiber substrate 12A; spiral winding and braiding can be used together to form the reinforcing fiber substrate 12A, or spiral winding alone can be used.

[0050] (Process for forming reinforcing layer 12)

[0051] A preform 10A having a reinforced fiber substrate 12A formed in the hollow lining 11 as described above is formed. Figure 6 , Figure 7 The reinforcing layer 12 is then placed within the molding die 93 (between the lower die 93A and the upper die 93B, also known as the cavity). Next, the reinforcing layer 12 is formed using RTM impregnation technology.

[0052] Specifically, gas is applied to the receiving space S of the lining 11 via a gas supply pipe 95 embedded in the molding mold 93, and a matrix resin 11B is injected between the molding mold 93 and the lining 11 (specifically, inside the cavity), thereby impregnating the reinforcing fiber substrate 12A with the matrix resin 11B and forming a reinforcing layer 12.

[0053] Here, when the base resin 11B is a thermosetting resin, the impregnated base resin can be thermoset at a heating temperature above the curing start temperature after impregnation with the base resin 11B. Alternatively, the molding die 93 can be heated at a heating temperature above the pre-curing start temperature, and the base resin can be thermoset simultaneously with impregnation. On the other hand, when the base resin 11B is a thermoplastic resin, after impregnating the base resin 11B while it is heated to a state above its softening point, it is cooled and cured.

[0054] Furthermore, when injecting the base resin 11B between the molding mold 93 and the liner 11 (specifically, inside the cavity), the base resin 11B is injected via the resin injection pipe (also called the resin injection gate) 92 connected to the resin injection machine 91. At the same time, the air between the molding mold 93 and the liner 11 (specifically, inside the cavity) is degassed via the vacuum degassing pipe 97 connected to the vacuum pump 98.

[0055] Furthermore, if internal pressure is applied to the storage space S of the liner 11 and the matrix resin 11B is injected between the molding die 93 and the liner 11, the following phenomenon occurs. Specifically, as... Figure 8 As shown in part A, the circumferential stress T acts on the cylindrical portion 14 of the lining 11 in a manner that expands circumferentially toward the cylindrical portion 14, thus making it less likely for the reinforcing fibers wrapped around the cylindrical portion 14 of the lining 11 to deviate from their winding direction.

[0056] However, as Figure 8 As shown in section B, the boundary portion 16 between the cylinder portion 14 and the neck 15 is concave, and this shape causes the circumferential stress T to act in a way that reduces the diameter of the boundary portion 16 circumferentially. Due to this circumferential stress T, the diameter of the boundary portion 16 is slightly reduced, making it easy for the reinforcing fibers 12a of the reinforcing fiber substrate 12A wrapped around the boundary portion 16 to loosen. This phenomenon becomes more pronounced, especially when degassing is performed using the vacuum pump 98. In this state, even if the matrix resin 11B is impregnated with the reinforcing fiber substrate 12A, it is difficult to ensure the mechanical strength of the boundary portion 16.

[0057] Therefore, in this embodiment, a metal reinforcement 40 is provided at the boundary portion 16 between the neck 15 of the liner 11 and the cylindrical portion 14, thereby suppressing circumferential deformation of the boundary portion 16. As a result, the matrix resin 11B can be impregnated into the reinforcing fiber substrate 12A while suppressing the loosening of the reinforcing fibers wrapped around the boundary portion 16. Consequently, a high-pressure tank 10 with stable strength can be obtained.

[0058] In particular, in this embodiment, the reinforcing body 40 is integrally formed with the lining body 11A, thus constraining the lining body 11A to the reinforcing body 40. Therefore, even if the circumferential stress T acts on the boundary portion 16 in a manner that reduces in the circumferential direction, the shape of the boundary portion 16 can be maintained.

[0059] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the embodiments described above. Various design changes can be made without departing from the spirit of the present invention as set forth in the claims.

Claims

1. A method for manufacturing a high-pressure tank, the high-pressure tank comprising: a resin lining forming a fluid-receiving space, and having an opening at least at one end; A reinforcing layer, covering the outer peripheral surface of the lining, and composed of fiber-reinforced resin, is characterized in that... The method for manufacturing the high-pressure tank includes: As the lining, the process of preparing the following lining includes a lining body and a metal reinforcement, the lining body having a neck that is continuous with the cylindrical portion forming the storage space and extends toward the opening, and the metal reinforcement being disposed at least at the boundary between the neck and the cylindrical portion. The process of forming a reinforcing fiber substrate on the outer peripheral surface of the lining by winding reinforcing fibers on the outer peripheral surface of the lining; as well as The process of placing the liner wound with the reinforcing fiber substrate in a molding die, applying internal pressure to the receiving space, and injecting a matrix resin between the molding die and the liner, thereby impregnating the reinforcing fiber substrate with the matrix resin to form the reinforcing layer. In the process of preparing the lining, the reinforcing body is integrally formed with the lining body. The reinforcing body abuts against the outer peripheral surface of the neck in a manner that surrounds the outer peripheral surface of the neck. The end of the reinforcing body at the opening side is radially extended towards the reinforcing body.

2. The method for manufacturing a high-pressure tank according to claim 1, characterized in that, The high-pressure tank is equipped with a connecting component that covers the opening. The connecting member has an insertion portion that inserts into the opening. A sealing component that contacts the inner circumferential surface of the liner is installed in the insertion portion. The reinforcement extends to a position opposite the sealing member.

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