CN117489968A

CN117489968A - Method for manufacturing high-pressure tank

Info

Publication number: CN117489968A
Application number: CN202310614556.9A
Authority: CN
Inventors: 岸田知之; 泽井统
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2022-08-01
Filing date: 2023-05-29
Publication date: 2024-02-02
Also published as: JP2024019920A

Abstract

In the method for manufacturing a high-pressure tank according to the present invention, a liner is prepared, which comprises: a liner body having a neck portion continuous with the cylindrical body portion in which the accommodation space is formed and extending toward the opening portion; and a metal reinforcement disposed on the neck. The reinforcing fiber is wound around the outer peripheral surface of the liner, whereby a reinforcing fiber base material is formed on the outer peripheral surface of the liner. The reinforcing layer is formed by disposing the liner around which the reinforcing fiber base material is wound on the mold, applying an internal pressure to the storage space, and injecting a matrix resin between the mold and the liner, thereby impregnating the reinforcing fiber base material with the matrix resin.

Description

Method for manufacturing high-pressure tank

Technical Field

The present invention relates to a method for manufacturing a high-pressure tank.

Background

For example, a high-pressure tank for storing fuel gas is used in a natural gas vehicle, a fuel cell vehicle, or the like. The high-pressure tank is provided with a liner for containing a fluid as a high-pressure gas, and a reinforcing layer made of a fiber reinforced resin for covering the outer peripheral surface of the liner.

In manufacturing a high-pressure tank, first, a liner made of resin is prepared. The liner has a cylindrical body portion in which a receiving space for receiving the high-pressure gas is formed, and a neck portion formed continuously with an end portion of the cylindrical body portion. For the prepared liner, a reinforcing layer made of a fiber reinforced resin is molded on the outer peripheral surfaces of the tubular body and neck (for example, refer to japanese patent application laid-open No. 2020-60265).

Here, for example, in the case of forming the reinforcing layer shown in japanese patent application laid-open publication 2020-60265, it is assumed that the reinforcing fiber base material is formed on the outer peripheral surface of the liner by winding reinforcing fibers around the outer peripheral surface of the liner, and then the matrix resin is impregnated into the reinforcing fiber base material.

In this case, the liner around which the reinforcing fiber base material is wound is placed in the mold, an internal pressure is applied to the housing space of the liner, and a matrix resin is injected between the mold and the liner. At this time, since hoop stress acts on the tubular body portion of the liner so as to expand in the circumferential direction of the tubular body portion, the reinforcing fibers wound around the tubular body portion of the liner are less likely to deviate from winding.

However, since the boundary portion between the cylindrical body and the neck portion is concave, the hoop stress due to the shape acts so as to be reduced in the circumferential direction of the boundary portion. The diameter of the boundary portion is slightly reduced by the hoop stress, and the reinforcing fibers wound around the boundary portion are easily loosened. In this state, even if the matrix resin is impregnated with the reinforcing fibers (reinforcing fiber base material), it is difficult to secure the mechanical strength of the boundary portion.

Disclosure of Invention

The present invention has been made in view of such a point, and provides a method for manufacturing a high-pressure tank, which can obtain stable strength by impregnating a matrix resin while suppressing loosening of reinforcing fibers wound around a boundary portion.

In view of the above problems, a method for manufacturing a high-pressure tank according to the present invention is a method for manufacturing a high-pressure tank having a resin liner that forms a fluid storage space and has an opening formed at least at one end side, and a reinforcing layer made of a fiber reinforced resin that covers an outer peripheral surface of the liner, the method comprising: a step of preparing a liner having a liner body having a neck portion continuous with a tubular body portion in which the storage space is formed and extending toward the opening portion, and a metal reinforcement disposed at least at a boundary portion between the neck portion and the tubular body portion, as the liner; forming a reinforcing fiber base material on the outer peripheral surface of the liner by winding reinforcing fibers around the outer peripheral surface of the liner; and a step of disposing the liner around which the reinforcing fiber base material is wound in a mold, applying an internal pressure to the storage space, and injecting a matrix resin between the mold and the liner, thereby impregnating the reinforcing fiber base material with the matrix resin to form the reinforcing layer.

According to the present invention, when an internal pressure is applied to the receiving space formed by the liner at the time of forming the reinforcing layer, since the boundary portion between the neck portion and the cylindrical body portion of the liner is concave, hoop stress acts on the boundary portion so as to be reduced in the circumferential direction thereof. However, in the present invention, since the reinforcement made of metal is disposed at least at the boundary portion, deformation in the circumferential direction of the boundary portion can be suppressed. This makes it possible to impregnate the reinforcing fiber base material with the matrix resin while suppressing loosening of the reinforcing fibers wound around the boundary portion. As a result, a high-pressure tank with stable strength can be obtained.

In a more preferred embodiment, in the step of preparing the liner, the reinforcement body and the liner body are integrally molded.

According to this aspect, the reinforcement body is integrally molded with the liner body, and therefore the liner body is restrained to the reinforcement body. Therefore, even if hoop stress acts on the boundary portion in a manner to be reduced in the circumferential direction, the shape of the boundary portion can be maintained.

In a more preferred embodiment, the high-pressure tank is provided with a connecting member covering the opening, an insertion portion is formed in the connecting member, the insertion portion is provided with a sealing member which contacts an inner peripheral surface of the liner, and the reinforcing body extends to a position opposed to the sealing member.

According to this aspect, since the reinforcement member is extended to a position facing the seal member, the seal performance by the seal member can be ensured by the reinforcement member even when the high-pressure tank is used and the fluid is filled into and discharged from the storage space.

According to the present invention, the matrix resin is impregnated into the reinforcing fiber base material while loosening of the reinforcing fibers wound around the boundary portion is suppressed, and stable strength can be obtained.

Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which like reference numerals refer to like elements.

Drawings

Fig. 1 is a perspective view showing a structure of a tank unit including a high-pressure tank manufactured by the manufacturing method according to the present embodiment.

Fig. 2 is a sectional view of the high pressure tank taken along line II-II of fig. 1.

Fig. 3 is an enlarged cross-sectional view of a main portion of the high-pressure tank on the bracket side shown in fig. 2.

Fig. 4 is a sectional view for explaining a process of preparing a liner in the method of manufacturing a high-pressure tank shown in fig. 3.

Fig. 5 is a view for explaining a process of forming a reinforcing fiber base material in the method of manufacturing a high-pressure tank shown in fig. 1.

Fig. 6 is a view for explaining a state in which a reinforcing fiber base material is formed in the method for manufacturing a high-pressure tank shown in fig. 3.

Fig. 7 is a cross-sectional view for explaining a process of forming a reinforcing layer in the method of manufacturing a high-pressure tank shown in fig. 1.

Fig. 8 is a diagram for explaining hoop stress acting when forming a reinforcing layer in the method of manufacturing a high-pressure tank according to the present embodiment.

Detailed Description

1. With respect to the high pressure tank 10

First, referring to fig. 1 to 3, an embodiment of a tank unit 1 including a high-pressure tank 10 will be described. As shown in fig. 1 and 2, the tank unit 1 according to the present embodiment includes a plurality of high-pressure tanks 10 and a pair of connecting members 30, 30 connected to both ends of the high-pressure tanks 10.

The high-pressure tank 10 is a tank filled with high-pressure hydrogen gas, which is mounted on a fuel cell vehicle. The gas that can be filled in the high-pressure tank 10 is not limited to high-pressure hydrogen gas, and may be filled with compressed gases such as CNG (compressed natural gas), liquefied gases such as LNG (liquefied natural gas) and LPG (liquefied petroleum gas), other gases (fluids), or may be temporarily filled with fluids such as liquids for pressure resistance test.

The high-pressure tank 10 includes: a liner 11 forming a storage space S for storing hydrogen gas, and having openings 13 formed on both sides; and a reinforcing layer 12 laminated on the liner 11 so as to cover the outer peripheral surface 11a of the liner 11. The liner 11 is composed of a liner body 11A and a metal reinforcement 40, and the liner body 11A is composed of a resin material having gas barrier properties. The reinforcing layer 12 is made of fiber-reinforced resin.

The liner body 11A includes a tubular body 14 in which the storage space S is formed, and a pair of neck portions 15 and 15 continuous with the end of the tubular body 14 and in which the opening 13 is formed. In the present embodiment, the necks 15 and 15 are formed on both sides of the liner 11, but the high-pressure tank 10 may have a bottle-shaped structure in which the neck 15 is formed on only one side.

In the present embodiment, the cylindrical body 14 includes a cylindrical main body 14a as an example of a cylindrical shape, and a shoulder 14b having a reduced inner diameter and an reduced outer diameter as the main body 14a enters the end of the cylindrical body 14. The shoulder 14b is a truncated cone-shaped cylindrical portion, and a neck 15 is formed so as to be continuous with the shoulder 14b. The neck portion 15 is a cylindrical portion, and extends in a direction along the axis CL of the high-pressure tank 10 toward the opening portion 13. Therefore, the boundary portion 16 between the cylindrical body 14 (shoulder 14 b) and the neck 15 is formed in a concave shape in appearance.

In the present embodiment, a metal reinforcement 40 is disposed at the boundary portion 16 between the neck portion 15 and the tubular body portion 14. In order to ensure tightness as described later, the reinforcement 40 may extend to a part of the neck 15.

In the present embodiment, an annular joint 20 is attached to the outer peripheral surface 12b of the reinforcing layer 12 covering the neck portion 15. A plurality of projections are formed on the inner peripheral surface 22 of the joint 20, and the reinforcing layer 12 is formed so as to bite into the inner peripheral surface 22 (specifically, bite between the projections). This can lock the joint 20 and the reinforcing layer 12. A male screw is formed on the outer peripheral surface 21 of the joint 20, and the male screw can be screwed with a female screw of an inner wall surface 34 formed on a coupling member 30 to be described later.

Here, in the present embodiment, the resin constituting the liner body 11A is preferably a resin having good gas barrier properties. Examples of such resins include thermoplastic resins such as polypropylene resins, nylon resins (e.g., 6-nylon resins or 6, 6-nylon resins), polycarbonate resins, acrylic resins, ABS resins, polyamide resins, polyethylene resins, ethylene-vinyl alcohol copolymer resins (EVOH), and polyester resins.

The reinforcing layer 12 is formed by impregnating reinforcing fibers (reinforcing fiber base material) with a thermoplastic resin or a thermosetting resin as a matrix resin. In the present embodiment, the reinforcing fibers are fiber bundles. As the reinforcing fiber, a reinforcing fiber such as a glass fiber, an aramid fiber, a boron fiber, and a carbon fiber can be used, and in particular, a carbon fiber is preferably used from the viewpoints of lightweight property, mechanical strength, and the like. The base resin is preferably a thermosetting resin, and the thermosetting resin is a phenolic resin, a melamine resin, a urea resin, or an epoxy resin, and from the viewpoint of mechanical strength, an epoxy resin precursor is preferably used. The epoxy resin has fluidity in an uncured state and forms a strong crosslinked structure after heat curing.

The reinforcing layer 12 is formed by winding reinforcing fibers (reinforcing fiber bundles) impregnated with a matrix resin around the outer peripheral surface 11a of the liner 11 by a filament winding method or a sheet winding method. The reinforcing layer 12 may be a spirally wound layer in which the fiber bundles are wound so as to be inclined with respect to the axis CL of the high-pressure tank 10, for example, a layer (braiding machine winding) in which the fiber bundles are woven so as to be inclined with respect to the axis CL of the high-pressure tank 10, or may be formed by laminating these layers.

The pair of connection members 30, 30 are made of metal such as aluminum or steel, and are composed of a bracket 30A and a manifold 30B. The bracket 30A is a member for restraining the plurality of high-pressure tanks 10, 10, … as one body and mounted to the vehicle.

The manifold 30B is a member in which a gas flow path is formed that introduces hydrogen gas into the storage space S of the high-pressure tank 10 and discharges the hydrogen gas from the storage space S. As shown in fig. 2, the bracket 30A and the manifold 30B mainly have different gas flow paths, and therefore, the structure of the manifold 30B as the connecting member 30 will be described with reference to fig. 3.

The manifold 30B is formed so as to cover the opening 13 formed at the end of the high-pressure tank 10 in the axial direction CL, and the manifold 30B includes an insertion portion 31 and a cap portion 32. The cap portion 32 is a portion that is screwed to the joint 20 on the outer peripheral surface 21 of the joint 20 and covers the end surface of the high-pressure tank 10, and the insertion portion 31 is formed in the center of the cap portion 32.

The insertion portion 31 is a plug-like portion inserted into the neck portion 15 from the opening portion 13 along the inner peripheral surface 15a of the neck portion 15. An annular groove 35 is formed along the circumferential direction of the outer circumferential surface 31a of the insertion portion 31, and annular seal members 61, 62 for sealing the storage space S are disposed in the annular groove 35. Specifically, the seal members 61 and 62 are in contact with the inner peripheral surface 11b of the liner 11 (specifically, the inner peripheral surface 15a of the neck portion 15), and are in contact with the inner peripheral surface 11b in a state of being slightly elastically deformed in the radial direction in order to ensure the sealing property in the storage space S. The sealing members 61 and 62 are made of an elastic material such as a resin material or a rubber material having gas barrier properties.

In the present embodiment, the reinforcement 40 is cylindrical and is a member for restricting radial deformation of the inner peripheral surface 15a of the neck portion 15. The reinforcement 40 is disposed at the boundary portion 16 between the neck portion 15 of the liner body 11A and the tubular body 14. The reinforcement 40 is formed around the outer peripheral surface 15d of the neck portion 15 so as to restrict radial deformation of at least the boundary portion 16. In the present embodiment, the reinforcing body 40 is integrally formed with the liner body 11A.

In the present embodiment, the reinforcing body 40 extends to a position facing the seal members 61 and 62 so as to surround the outer peripheral surface 15d of the liner 11. Since the reinforcement 40 is extended to the position facing the seal members 61 and 62, the sealing performance by the seal members 61 and 62 can be ensured by the reinforcement 40 even when the high-pressure tank 10 is used and the fluid is filled into and discharged from the storage space S.

The material of the reinforcement 40 is not particularly limited as long as the deformation of the inner peripheral surface 15a of the neck portion 15 in the radial direction can be restricted by a metal material such as stainless steel or aluminum.

Here, the "radial deformation of the inner peripheral surface 15a of the neck portion 15" is a deformation when hoop stress is generated in the neck portion 15 due to the pressure of hydrogen gas, and is a deformation in which the liner 11 forming the neck portion 15 (more specifically, a portion of the liner 11 in contact with the seal members 61, 62) expands in the radial direction.

The inner peripheral surface (facing surface) of the reinforcement 40 is in contact with the outer peripheral surface 15d of the neck 15. In the present embodiment, the reinforcement 40 extends from the end surface of the high-pressure tank 10 to a part of the shoulder 14b of the cylindrical body 14. The opening 13-side end of the reinforcement 40 is formed in a shape expanding in the radial direction of the reinforcement 40, and the cylinder 14-side end is formed along the shape of the boundary portion 16. This facilitates engagement of the reinforcement 40 with the reinforcement layer 12, and prevents the reinforcement 40 from falling off in the direction along the axis CL.

2. Method for manufacturing high-pressure tank

Hereinafter, a method for manufacturing the high-pressure tank 10 according to the present embodiment will be described with reference to fig. 4 to 8.

(step of preparing liner 11)

First, as shown in fig. 4, a liner 11 including a liner body 11A made of resin and a reinforcement 40 made of metal is prepared. In the present embodiment, the reinforcing body 40 is disposed in an injection molding machine (not shown), and the liner body 11A is integrally molded with the reinforcing body 40. In the case of molding the liner body 11A, after molding two divided bodies that are perpendicular to the axis CL and are located at the center of the liner body 11A, the liner body 11A may be manufactured by joining the two divided bodies. Further, the liner body 11A may be arranged at the boundary portion 16 between the neck portion 15 and the tubular body 14 after being molded.

(step of forming reinforcing fiber base Material)

As shown in fig. 5 and 6, the reinforcing fiber 12A is wound around the outer peripheral surface 11a of the liner 11, whereby the reinforcing fiber base material 12A is formed on the outer peripheral surface 11a of the liner 11. Thereby, the preform 10A is formed. The continuous reinforcing fibers 12A are sequentially drawn from the plurality of bobbins 82, 82 of the braiding machine (or braiding machine) 80, the reinforcing fibers 12A are braided and wound around the outer peripheral surface of one neck portion 15, and the reinforcing fiber base material 12A is formed from the neck portion 15 on one side of the liner 11 to the tubular body portion 14 and the neck portion 15 on the other side. The reinforcing fiber base material 12A may be formed by repeating this method, the reinforcing fiber base material 12A may be formed by using spiral winding and braiding winding together, or the reinforcing fiber base material 12A may be formed by spiral winding alone.

(step of Forming reinforcing layer 12)

As described above, the preform 10A (fig. 6 and 7) having the reinforcing fiber base material 12A formed in the hollow liner 11 is placed in the mold 93 (between the lower mold 93A and the upper mold 93B, also referred to as a cavity). Next, the reinforcing layer 12 is molded using RTM impregnation techniques.

Specifically, the matrix resin 11B is impregnated into the reinforcing fiber base material 12A by applying an internal pressure to the storage space S of the liner 11 with a gas through the gas supply pipe 95 embedded in the mold 93 and injecting the matrix resin 11B between the mold 93 and the liner 11 (specifically, into the cavity), thereby forming the reinforcing layer 12.

Here, in the case where the matrix resin 11B is a thermosetting resin, the impregnated matrix resin may be thermally cured at a heating temperature equal to or higher than the curing start temperature after the impregnation of the matrix resin 11B. The mold 93 may be heated at a heating temperature equal to or higher than the initial temperature of the preliminary curing, and the matrix resin may be thermally cured while being impregnated. On the other hand, in the case where the matrix resin 11B is a thermoplastic resin, the matrix resin 11B is impregnated with the matrix resin 11B in a state of being heated to a softening point or higher, and then cooled to be solidified.

When the matrix resin 11B is injected between the mold 93 and the liner 11 (specifically, in the cavity), the matrix resin 11B is injected through a resin injection pipe (also referred to as a resin injection gate) 92 connected to the resin injector 91. At the same time, air between the mold 93 and the liner 11 (specifically, the cavity) is degassed via a vacuum degassing pipe 97 connected to a vacuum pump 98.

When an internal pressure is applied to the storage space S of the liner 11 and the matrix resin 11B is injected between the mold 93 and the liner 11, the following phenomenon occurs. Specifically, as shown in a portion a of fig. 8, the hoop stress T acts on the tubular body 14 of the liner 11 so as to expand in the circumferential direction of the tubular body 14, and therefore, the winding deviation of the reinforcing fibers wound around the tubular body 14 of the liner 11 is less likely to occur.

However, as shown in part B of fig. 8, the boundary portion 16 between the cylindrical body 14 and the neck portion 15 has a concave shape, and therefore the hoop stress T is caused by this shape to act so as to be reduced in the circumferential direction of the boundary portion 16. By this hoop stress T, the diameter of the boundary portion 16 is slightly reduced, and the reinforcing fibers 12A of the reinforcing fiber base material 12A wound around the boundary portion 16 are easily loosened. In particular, if the degassing is performed by the vacuum pump 98, such a phenomenon becomes more remarkable. In this state, even if the matrix resin 11B is impregnated into the reinforcing fiber base material 12A, it is difficult to secure the mechanical strength of the boundary portion 16.

Therefore, in the present embodiment, since the metal reinforcing body 40 is disposed at the boundary portion 16 between the neck portion 15 of the liner 11 and the tubular body 14, deformation in the circumferential direction of the boundary portion 16 can be suppressed. This makes it possible to impregnate the matrix resin 11B into the reinforcing fiber base material 12A while suppressing loosening of the reinforcing fibers wound around the boundary portion 16. As a result, the high-pressure tank 10 having stable strength can be obtained.

In particular, in the present embodiment, since the reinforcing body 40 is integrally molded with the liner body 11A, the liner body 11A is restrained by the reinforcing body 40. Therefore, even if the hoop stress T acts on the boundary portion 16 in a manner to be reduced in the circumferential direction, the shape of the boundary portion 16 can be maintained.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and 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 of manufacturing a high pressure tank, the high pressure tank comprising: a resin liner forming a storage space for storing a fluid, and having an opening at least at one end side; and a reinforcing layer covering the outer peripheral surface of the liner and made of fiber reinforced resin, characterized in that,

the manufacturing method of the high-pressure tank comprises the following steps:

a step of preparing a liner having a liner body and a metal reinforcing body, wherein the liner body has a neck portion continuous with a tubular body portion in which the storage space is formed and extending toward the opening, and the metal reinforcing body is disposed at least at a boundary portion between the neck portion and the tubular body portion;

forming a reinforcing fiber base material on the outer peripheral surface of the liner by winding reinforcing fibers around the outer peripheral surface of the liner; and

and a step of forming the reinforcing layer by disposing the liner around which the reinforcing fiber base material is wound in a mold, applying an internal pressure to the storage space, and injecting a matrix resin between the mold and the liner, thereby impregnating the matrix resin into the reinforcing fiber base material.

2. The method for manufacturing a high-pressure tank according to claim 1, wherein,

in the step of preparing the liner, the reinforcement body is integrally molded with the liner body.

3. The method for manufacturing a high-pressure tank according to claim 1, wherein,

the high-pressure tank is provided with a connecting member covering the opening,

an insertion portion inserted into the opening portion is formed in the connection member,

a sealing member contacting the inner peripheral surface of the liner is mounted on the insertion portion,

the reinforcement extends to a position opposed to the seal member.