Hydrogen tank manufacturing method

Abstract

This invention provides a method for manufacturing a hydrogen tank that allows for the thinning of the liner. [Solution] The method for manufacturing a hydrogen tank includes a dome reinforcement layer forming step S1 for forming a hollow dome reinforcement layer, a dome liner forming step S2 for forming a dome liner on the inner wall surface of the dome reinforcement layer by resin coating, a pipe reinforcement layer forming step S3 for forming a hollow pipe reinforcement layer, a pipe liner forming step S4 for forming a pipe liner on the inner wall surface of the pipe reinforcement layer by resin coating, and a joining step S5 for joining two dome-shaped divisions having a dome liner and a dome reinforcement layer covering the outer surface of the dome liner, and a pipe-shaped division having a pipe liner and a pipe reinforcement layer covering the outer surface of the pipe liner.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a hydrogen tank.

Background Art

[0002] As a hydrogen tank mounted on a fuel cell vehicle or the like, there is known one including a liner having a cylindrical pipe portion and a pair of dome liners provided at both axial ends of the pipe portion, and a reinforcing layer made of a fiber-reinforced resin covering the outer peripheral surface of the liner. Such a hydrogen tank having such a structure is manufactured, for example, as described in Patent Document 1, by first forming a resin-made hollow liner and winding a fiber bundle impregnated with resin around the outer peripheral surface of the formed liner by a filament winding method (FW method) to form a reinforcing layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The liner described in Patent Document 1 above is formed by injection molding or blow molding using a resin material. However, since injection molding and blow molding are not suitable for manufacturing a liner having a thickness less than the order of mm, there has been a problem that it is difficult to make the liner thinner.

[0005] The present invention has been made to solve such technical problems, and an object thereof is to provide a method for manufacturing a hydrogen tank capable of making the liner thinner.

Means for Solving the Problems

[0006] A method for manufacturing a hydrogen tank according to the present invention is a method for manufacturing a hydrogen tank comprising joining two dome-shaped divisions, each having a dome liner and a dome reinforcing layer covering the outer surface of the dome liner, and a pipe-shaped division having a pipe liner and a pipe reinforcing layer covering the outer surface of the pipe liner, the method comprising: a dome-shaped division manufacturing step of first forming the hollow dome reinforcing layer and then forming the dome liner on the inner wall surface of the formed dome reinforcing layer by resin coating or plating; a pipe-shaped division manufacturing step of first forming the hollow pipe reinforcing layer and then forming the pipe liner on the inner wall surface of the formed pipe reinforcing layer by resin coating or plating; and a joining step of joining the two dome-shaped divisions and the pipe-shaped division.

[0007] According to the hydrogen tank manufacturing method of the present invention, in the dome segment manufacturing step or pipe segment manufacturing step, a hollow dome reinforcement layer or pipe reinforcement layer is formed first, and a dome liner or pipe liner is formed on the inner wall surface of the formed dome reinforcement layer or pipe reinforcement layer by resin coating or plating. In this way, it becomes possible to form a thin liner compared to conventional methods of forming the liner by injection molding or blow molding. As a result, the liner can be made thinner. [Effects of the Invention]

[0008] According to the present invention, it is possible to make the liner thinner. [Brief explanation of the drawing]

[0009] [Figure 1] This is a process diagram showing a method for manufacturing a hydrogen tank according to an embodiment. [Figure 2] This is a schematic cross-sectional view illustrating the fabrication of the dome segment. [Figure 3] This is a schematic cross-sectional view illustrating the fabrication of a pipe section. [Figure 4] This is a schematic cross-sectional view illustrating the joint between the dome section and the pipe section. [Modes for carrying out the invention]

[0010] The following describes an embodiment of the hydrogen tank manufacturing method according to the present invention with reference to the drawings, but before that, the structure of the hydrogen tank will be briefly explained based on Figure 4(b).

[0011] [About hydrogen tanks] As shown in Figure 4(b), the hydrogen tank 1 of this embodiment comprises a substantially cylindrical liner 2 having a space for storing high-pressure hydrogen, a reinforcing layer 3 covering the outer surface of the liner 2, and a nozzle 4 attached to one end of the liner 2.

[0012] Liner 2 is formed of a material having hydrogen barrier properties. This liner 2 consists of a cylindrical pipe liner 21 and a pair of dome liners (first dome liner 22, second dome liner 23) provided on both sides of the pipe liner 21 in the axial direction (i.e., the axial direction L of the hydrogen tank 1). The pipe liner 21 extends for a predetermined length along the axial direction L of the hydrogen tank 1. The first dome liner 22 and the second dome liner 23 are formed continuously on both sides of the pipe liner 21 and each decreases in diameter as it moves away from the pipe liner 21.

[0013] Of the first dome liner 22 and the second dome liner 23, the aforementioned nozzle 4 is fitted into the center of the first dome liner 22. The nozzle 4 is made of a metal material such as aluminum or an aluminum alloy, which has been processed into a predetermined shape.

[0014] The reinforcing layer 3 has the function of reinforcing the liner 2 and improving the mechanical strength of the hydrogen tank 1, such as rigidity and pressure resistance, and is formed of fiber-reinforced resin in which reinforcing fibers are impregnated with resin. The reinforcing layer 3 includes a pipe reinforcing layer 31 that covers the outer surface of the pipe liner 21, a first dome reinforcing layer 32 that covers the outer surface of the first dome liner 22, and a second dome reinforcing layer 33 that covers the outer surface of the second dome liner 23.

[0015] The pipe reinforcement layer 31 is a reinforcement layer corresponding to the pipe liner 21 and has a cylindrical shape following the shape of the pipe liner 21. The reinforcing fibers used in the pipe reinforcement layer 31 are circumferentially oriented at an angle substantially orthogonal to the axial direction L of the hydrogen tank 1. In other words, the reinforcing fibers of the pipe reinforcement layer 31 are oriented in the circumferential direction of the hydrogen tank 1.

[0016] The first dome reinforcement layer 32 is a reinforcement layer corresponding to the first dome liner 22 and has a dome shape following the shape of the first dome liner 22. The reinforcing fibers used in the first dome reinforcement layer 32 are not oriented in the circumferential direction of the hydrogen tank 1 but extend in various directions intersecting the circumferential direction of the hydrogen tank 1. Also, a through hole 321 is formed at the center of the first dome reinforcement layer 32. The above-mentioned base 4 is inserted through the through hole 321.

[0017] The second dome reinforcement layer 33 is a reinforcement layer corresponding to the second dome liner 23 and has a dome shape following the shape of the second dome liner 23. The second dome reinforcement layer 33 is formed of a fiber-reinforced resin in which reinforcing fibers are impregnated with resin. The reinforcing fibers of the second dome reinforcement layer 33 are not oriented in the circumferential direction of the hydrogen tank 1 but extend in various directions intersecting the circumferential direction of the hydrogen tank 1.

[0018] Note that the reinforcing fibers of the pipe reinforcement layer 31 and the reinforcing fibers of the first dome reinforcement layer 32 or the second dome reinforcement layer 33 are not continuous (not connected). This is because, as will be described later, the pipe reinforcement layer 31 and the first dome reinforcement layer 32 or the second dome reinforcement layer 33 are separately manufactured.

[0019] In the present embodiment, the pipe liner 21 and the pipe reinforcement layer 31 covering the outer peripheral surface of the pipe liner 21 constitute the pipe split body 11, the first dome liner 22 and the first dome reinforcement layer 32 covering the outer peripheral surface of the first dome liner 22 constitute the first dome split body 12, and the second dome liner 23 and the second dome reinforcement layer 33 covering the outer peripheral surface of the second dome liner 23 constitute the second dome split body 13.

[0020] Then, in the axial direction L of the hydrogen tank 1, the pipe split body 11, the first dome split body 12, and the second dome split body 13 are integrally formed by joining one end of the pipe split body 11 to the first dome split body 12 and the other end of the pipe split body 11 to the second dome split body 13.

[0021] [Method for manufacturing a hydrogen tank] Hereinafter, a method for manufacturing the hydrogen tank 1 will be described. As shown in FIG. 1, the method for manufacturing the hydrogen tank 1 includes a dome reinforcing layer forming step S1, a dome liner forming step S2, a pipe reinforcing layer forming step S3, a pipe liner forming step S4, and a joining step S5. The dome reinforcing layer forming step S1 and the dome liner forming step S2 respectively correspond to the "dome split body manufacturing step" described in the claims, and the pipe reinforcing layer forming step S3 and the pipe liner forming step S4 respectively correspond to the "pipe split body manufacturing step" described in the claims.

[0022] Note that the dome split body manufacturing step (dome reinforcing layer forming step S1 to dome liner forming step S2) and the pipe split body manufacturing step (pipe reinforcing layer forming step S3 to pipe liner forming step S4) are independent of each other, so they may be performed in parallel or either one may be performed first. In the present embodiment, the dome reinforcing layer forming step S1 to the pipe liner forming step S4 will be described in this order.

[0023] In the dome reinforcing layer forming step S1, first, for example, by the FW method, a plurality of fiber bundles F1 impregnated with resin are wound around the outer peripheral surface of the mandrel 100 (see FIG. 2(a)). The mandrel 100 is, for example, made of metal and has a main body portion 101 and a shaft portion 102 that protrudes outward from one end of the main body portion 101. The main body portion 101 is formed in a circular shape when viewed from the axial direction of the shaft portion 102. A groove portion 101a extending over one circumference in the circumferential direction is formed on the outer peripheral surface at the axial center of the main body portion 101. The shaft portion 102 has the same diameter as the outer diameter of the base 4 and is rotatably supported by a rotation mechanism (not shown).

[0024] Then, by rotating the mandrel 100, the resin-impregnated fiber bundle F1 is wound around the mandrel 100 to cover its outer surface, forming the wound body 30. At this time, the presence of the shaft portion 102 creates a through hole (i.e., a through hole 321) where the shaft portion 102 is located.

[0025] The resin used to impregnate the fiber bundle F1 can be a thermosetting resin or a thermoplastic resin. Examples of thermosetting resins include phenolic resin, melamine resin, urea resin, and epoxy resin. Examples of thermoplastic resins include polyether ether ketone, polyphenylene sulfide, polyacrylic acid ester, polyimide, polyamide, and nylon 6. The fibers constituting the fiber bundle F1 can be glass fibers, aramid fibers, boron fibers, and carbon fibers, and carbon fibers are particularly preferred from the viewpoint of lightness and mechanical strength.

[0026] In this embodiment, the resin-impregnated fiber bundle F1 is carbon fiber reinforced polymer (CFRP) impregnated with epoxy resin.

[0027] Next, while rotating the mandrel 100, the cutting edge of the cutter 110 is inserted into the groove 101a of the mandrel 100 to divide the wound body 30, which is wound around the outer circumference of the mandrel 100, into two parts. This forms a pair of hollow dome reinforcement layers. Of the pair of formed dome reinforcement layers, the one with the through hole 321 is designated as the first dome reinforcement layer 32, and the one without the through hole 321 is designated as the second dome reinforcement layer 33 (see Figure 2(b)). Subsequently, the pre-fabricated mouthpiece 4 is attached to the through hole 321 (see Figure 2(c)).

[0028] In the dome liner formation process S2, the first dome liner 22 is formed by applying a resin coating or plating treatment to the inner wall surface of the first dome reinforcing layer 32, and the second dome liner 23 is formed by applying a resin coating or plating treatment to the inner wall surface of the second dome reinforcing layer 33. Examples of resin coatings include electrostatic powder coating, spray coating in solution, and application.

[0029] In this embodiment, a first dome liner 22 and a second dome liner 23 having a predetermined film thickness (e.g., 500 μm or less) are formed on the inner wall surfaces of the first dome reinforcement layer 32 and the second dome reinforcement layer 33, respectively, by resin coating. The resin used for resin coating is a resin with excellent hydrogen barrier properties and a hydrogen permeability coefficient of 6 × 10⁻⁶. -11 cm 3 ·cm / (cm 2 It is preferable that the resin has a hydrogen permeability coefficient of 5 × 10⁻¹⁰ sec·cmHg or less. -11 cm 3 ·cm / (cm 2 It is more preferable that the resin has a value of less than or equal to (sec·cmHg). This makes it possible to suppress the deterioration of hydrogen barrier properties due to a decrease in the thickness of the liner.

[0030] Examples of such resins include crystalline polymers such as EVOH (Ethylene Vinylalcohol Copolymer) and resins whose hydrogen permeability has been improved by the addition of nanofillers. In addition to EVOH, thermoplastic resins such as polyamide, polyethylene, and polyester, or thermosetting resins such as epoxy may also be used. When forming the liner by plating, a thin metal film having excellent hydrogen barrier properties and a predetermined film thickness (e.g., 500 μm or less) should be formed.

[0031] After forming the first dome liner 22 on the inner wall surface of the first dome reinforcement layer 32 and the second dome liner 23 on the inner wall surface of the second dome reinforcement layer 33, the materials are solidified (if thermoplastic resin is used) or cured (if thermosetting resin is used). This produces the first dome segment 12 and the second dome segment 13 (see Figure 2(d)).

[0032] In the pipe reinforcement layer formation step S3, a pipe reinforcement layer 31 is formed by winding a fiber bundle F2 impregnated with resin around the outer surface of, for example, a cylindrical mandrel 200 (see Figure 3(a)). The mandrel 200 is made of, for example, metal and has the same diameter as the inner diameter of the pipe reinforcement layer 31.

[0033] In this process, the mandrel 200 is rotated circumferentially by a rotating mechanism (not shown), and the resin-impregnated fiber bundle F2 is wrapped around the mandrel 200 multiple times so that the reinforcing fibers are oriented circumferentially around the mandrel 200. This forms a pipe reinforcement layer 31 with reinforcing fibers oriented circumferentially. The resin-impregnated fiber bundle F2 is, like the fiber bundle F1 described above, a carbon fiber reinforced polymer (CFRP) impregnated with epoxy resin.

[0034] Next, the epoxy resin impregnated into the fiber bundle F2 is cured by heating, and then the pipe reinforcement layer 31 is removed from the mandrel 200. This forms a hollow pipe reinforcement layer 31 (see Figure 3(b)).

[0035] In the pipe liner formation step S4, the pipe liner 21 is formed by resin coating or plating the inner wall surface of the pipe reinforcement layer 31. In this embodiment, the pipe liner 21 having a predetermined film thickness (for example, 500 μm or less) is formed on the inner wall surface of the pipe reinforcement layer 31 by resin coating, similar to the dome liner formation step S2 described above. The resin used for resin coating is a resin whose hydrogen permeability has been improved by adding crystalline polymers such as EVOH or nanofillers, similar to the dome liner formation step S2 described above.

[0036] After forming the pipe liner 21 on the inner wall surface of the pipe reinforcement layer 31, it is solidified (if a thermoplastic resin is used) or cured (if a thermosetting resin is used). This produces the pipe segment 11 (see Figure 3(c)).

[0037] In joining step S5, the fabricated pipe section 11 and a pair of dome sections (first dome section 12 and second dome section 13) are joined together to form the hydrogen tank 1. Specifically, as shown in Figure 4(a), first, one end of the pipe section 11 and the end of the first dome section 12 are butted together and fixed with adhesive. Next, the other end of the pipe section 11 and the end of the second dome section 13 are butted together and fixed with adhesive. This completes the manufacturing of the hydrogen tank 1 (see Figure 4(b)).

[0038] According to the manufacturing method of the hydrogen tank 1 of this embodiment, a hollow dome reinforcement layer (first dome reinforcement layer 32, second dome reinforcement layer 33) or pipe reinforcement layer 31 is first formed, and a dome liner (first dome liner 22, second dome liner 23) or pipe liner 21 is directly formed on the inner wall surface of the formed dome reinforcement layer (first dome reinforcement layer 32, second dome reinforcement layer 33) or pipe reinforcement layer 31 by resin coating. In this way, it becomes possible to form a thin liner 2 compared to conventional injection molding or blow molding methods. That is, a liner with a thickness of less than a millimeter can be easily manufactured. As a result, the liner 2 can be made thinner.

[0039] Furthermore, since the liner 2 can be made thinner, it is possible to store more hydrogen compared to conventional hydrogen tanks of the same shape and dimensions, thereby increasing the hydrogen storage density (hydrogen storage density (wt%) = amount of hydrogen stored / weight of the container). In addition, since the liner 2 can be made thinner, it becomes easier to reduce the weight of the hydrogen tank 1, further increasing the hydrogen storage density. Moreover, compared to conventional injection molding or blow molding to form the liner, molding dies are not required, thus reducing the cost of manufacturing equipment.

[0040] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of symbols]

[0041] 1: Hydrogen tank, 2: Liner, 3: Reinforcement layer, 4: Connector, 11: Pipe segment, 12: First dome segment, 13: Second dome segment, 21: Pipe liner, 22: First dome liner, 23: Second dome liner, 30: Winding, 31: Pipe reinforcement layer, 32: First dome reinforcement layer, 33: Second dome reinforcement layer, 321: Through hole

Claims

[Claim 1] A method for manufacturing a hydrogen tank, comprising joining together two dome-shaped divisions, each having a dome liner and a dome reinforcing layer covering the outer surface of the dome liner, and a pipe-shaped division having a pipe liner and a pipe reinforcing layer covering the outer surface of the pipe liner, A dome segment manufacturing process involves first forming the hollow dome reinforcing layer, and then forming the dome liner on the inner wall surface of the formed dome reinforcing layer by resin coating or plating, A pipe segment manufacturing process involves first forming the hollow pipe reinforcement layer, and then forming the pipe liner on the inner wall surface of the formed pipe reinforcement layer by resin coating or plating, A joining process for joining the two dome divisions and the pipe division, A method for manufacturing a hydrogen tank, characterized by including [the necessary components].

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