Hydrogen tank manufacturing method

Abstract

The present invention provides a method for manufacturing a hydrogen tank that enables the thinning of the pipe liner and prevents the occurrence of wrinkles and voids. [Solution] The method for manufacturing a hydrogen tank includes a pipe liner formation step S1, a pipe reinforcement layer formation step S2, a drawing step S3, a dome reinforcement layer formation step S4, a dome liner formation step S5, and a joining step S6. In the pipe liner formation step S1, a pipe liner is formed by heating the mandrel and shrink film together while the mandrel is inserted through the tubular shrink film. In the pipe reinforcement layer formation step S2, a pipe reinforcement layer is formed by winding multiple fiber bundles impregnated with resin around the outer surface of the formed pipe liner. In the drawing step S3, the pipe liner and pipe reinforcement layer formed on the mandrel are drawn out from the mandrel.

Description

Technical Field

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[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 is a problem that it is difficult to make the liner thinner. Also, in the case of injection molding and blow molding, gaps (voids) are likely to occur, so wrinkles and voids may also occur.

[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 pipe liner thinner and preventing the occurrence of wrinkles and voids.

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: a pipe division manufacturing step for manufacturing a pipe division having a cylindrical pipe liner and a pipe reinforcing layer covering the outer surface of the pipe liner; a dome division manufacturing step for manufacturing a dome division; and a joining step for joining the dome divisions manufactured in the dome division manufacturing step to both ends of the pipe division manufactured in the pipe division manufacturing step, wherein the pipe division manufacturing step comprises: a pipe liner forming step for forming the pipe liner by heating and bringing the mandrel and the shrink film into close contact while the mandrel is inserted through the shrink film; a pipe reinforcing layer forming step for forming the pipe reinforcing layer by winding a plurality of fiber bundles impregnated with resin around the outer surface of the formed pipe liner; and a withdrawal step for withdrawing the pipe liner and the pipe reinforcing layer formed on the mandrel from the mandrel. do.

[0007] In the hydrogen tank manufacturing method according to the present invention, a pipe liner is formed by heating the mandrel and shrink film together while the mandrel is inserted through the shrink film. This makes it possible to form a thin pipe liner compared to conventional injection molding or blow molding methods. Therefore, pipe liners with a thickness of less than a millimeter can be easily manufactured, thus enabling the thinning of pipe liners. Furthermore, the shrink film has the property of shrinking when heated; that is, it is a film that shrinks when heat is applied. By using a shrink film with such properties, a pipe liner can be formed on the mandrel without wrinkles or voids. [Effects of the Invention]

[0008] According to the present invention, it is possible to thin the pipe liner and prevent the occurrence of wrinkles and voids. [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 a pipe section. [Figure 3] This is a schematic cross-sectional view illustrating the fabrication of the dome segment. [Figure 4] This is a schematic cross-sectional view illustrating the joint between the pipe section and the dome 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 oriented circumferentially at an angle approximately perpendicular to the axis L direction 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 that follows 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. In addition, a through hole 321 is formed in the center of the first dome reinforcement layer 32. The aforementioned nozzle 4 is inserted through this 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 that follows the shape of the second dome liner 23. The second dome reinforcement layer 33 is formed of 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 that intersect with the circumferential direction of the hydrogen tank 1.

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

[0019] In this embodiment, the pipe liner 21 and the pipe reinforcing 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 reinforcing 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 reinforcing 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] [Regarding the manufacturing method of the hydrogen tank] Hereinafter, the manufacturing method of the hydrogen tank 1 will be described. As shown in FIG. 1, the manufacturing method of the hydrogen tank 1 includes a pipe liner forming step S1, a pipe reinforcing layer forming step S2, a drawing step S3, a dome reinforcing layer forming step S4, a dome liner forming step S5, and a joining step S6. And the pipe liner forming step S1, the pipe reinforcing layer forming step S2, and the drawing step S3 correspond to the "pipe split body manufacturing step" described in the claims, and the dome reinforcing layer forming step S4 and the dome liner forming step S5 correspond to the "dome split body manufacturing step" described in the claims.

[0022] Note that the pipe segment fabrication process (pipe liner formation process S1 to drawing process S3) and the dome segment fabrication process (dome reinforcement layer formation process S4 and dome liner formation process S5) are independent of each other and may be carried out in parallel or one may be carried out first. In this embodiment, the process will be described in the order of pipe liner formation process S1 to dome liner formation process S5.

[0023] In the pipe liner forming process S1, first, a cylindrical mandrel 100 is prepared (see Figure 2(a)). The mandrel 100 is made of metal, for example, and has the same diameter as the inner diameter of the pipe liner 21.

[0024] Next, a pre-formed cylindrical shrink film 110 is passed through the mandrel 100. Then, with the mandrel 100 inserted through the cylindrical shrink film 110, the mandrel 100 is heated, and the mandrel 100 and the shrink film 110 are brought into close contact to form the pipe liner 21 (see Figure 2(b)).

[0025] The shrink film 110 is a pre-stretched resin thin film that has the property of shrinking to its pre-stretch dimensions when heated. Examples of materials used for such shrink films 110 include polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS), polyethylene (PE), polypropylene (PP), and polyolefin (PO). In this embodiment, PET, which has relatively high strength, is used.

[0026] In the pipe reinforcement layer formation step S2, the pipe reinforcement layer 31 is formed by winding multiple resin-impregnated fiber bundles 120 around the outer surface of the pipe liner 21 formed on the mandrel 100 using the FW method. In this process, the resin-impregnated fiber bundles 120 are wound around the mandrel 100 multiple times so that the reinforcing fibers are oriented in the circumferential direction of the mandrel 100. This forms a pipe reinforcement layer 31 in which the reinforcing fibers are oriented in the circumferential direction.

[0027] The resin used to impregnate the fiber bundle 120 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 120 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.

[0028] In this embodiment, the resin-impregnated fiber bundle 120 is carbon fiber reinforced polymer (CFRP) impregnated with epoxy resin.

[0029] Next, the epoxy resin impregnated into the fiber bundle 120 is cured by heating. This transfers the shrink film 110 to the CFRP without wrinkles, and a pipe reinforcement layer 31 is formed on the outer surface of the pipe liner 21 (see Figure 2(c)).

[0030] In the drawing process S3, the pipe liner 21 and pipe reinforcement layer 31 formed on the mandrel 100 are drawn out from the mandrel 100. This produces a pipe section 11 having the pipe liner 21 and pipe reinforcement layer 31 (see Figure 2(d)).

[0031] In the dome reinforcement layer formation step S4, first, multiple fiber bundles 220 impregnated with resin are wound around the outer surface of the mandrel 200, for example, by the FW method (see Figure 3(a)). The mandrel 200 is made of metal, for example, and has a main body portion 201 and a shaft portion 202 that protrudes outward from one end of the main body portion 201. The main body portion 201 is formed in a circular shape when viewed from the axial direction of the shaft portion 202. A groove portion 201a extending circumferentially over a full circumference is formed on the outer surface of the main body portion 201 at the axial center. The shaft portion 202 has the same diameter as the outer diameter of the mouthpiece 4 and is rotatably supported by a rotating mechanism (not shown).

[0032] Then, by rotating the mandrel 200, the resin-impregnated fiber bundle 220 is wound around the outer surface of the mandrel 200 to form the wound body 30. At this time, the presence of the shaft portion 202 creates a through hole (i.e., a through hole 321) where the shaft portion 202 is located.

[0033] The resin-impregnated fiber bundle 220 is, like the fiber bundle 120 described above, a carbon fiber reinforced polymer (CFRP) impregnated with epoxy resin.

[0034] Next, while rotating the mandrel 200, the cutting edge of the cutter 210 is inserted into the groove 201a of the mandrel 200 to divide the wound body 30, which is wound around the outer circumference of the mandrel 200, 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 3(b)). Subsequently, the pre-fabricated nozzle 4 is attached to the through hole 321 (see Figure 3(c)).

[0035] In the dome liner formation step S5, the first dome liner 22 and the second dome liner 23 are formed by applying a liquid or softened resin material to the inner wall surface of the first dome reinforcement layer 32 and the inner wall surface of the second dome reinforcement layer 33, or by attaching a sheet made of resin material. The resin material used here has excellent hydrogen barrier properties.

[0036] 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, respectively (see Figure 3(d)).

[0037] In joining process S6, 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] In the manufacturing method of the hydrogen tank 1 according to this embodiment, the mandrel 100 is inserted into the tubular shrink film 110, and the mandrel 100 and the shrink film 110 are heated to bring them into close contact, thereby forming a pipe liner 21. In this way, it is possible to form a thin pipe liner 21 compared to conventional injection molding or blow molding methods. Therefore, a pipe liner 21 with a thickness of less than a millimeter (for example, 100 μm or less) can be easily manufactured, and the pipe liner 21 can be made thinner.

[0039] Furthermore, since the pipe liner 21 can be made thinner, more hydrogen can be stored compared to conventional hydrogen tanks of the same shape and dimensions, and the hydrogen storage density (hydrogen storage density (wt%) = amount of hydrogen stored / weight of the container alone) can be increased. Moreover, since the pipe liner 21 can be made thinner, it becomes easier to reduce the weight of the hydrogen tank 1, and the hydrogen storage density can be increased even further.

[0040] Furthermore, the shrink film 110 has the property of shrinking when heated. By using a shrink film 110 with such properties, the pipe liner 21 can be formed on the mandrel 100 without wrinkles or voids.

[0041] 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.

[0042] For example, the dome segments (first dome segment 12 and second dome segment 13) may be manufactured in the same manner as the pipe segment 11, by covering a pre-formed dome-shaped shrink film onto a mandrel, heating to bring the two together to form a dome liner, and then forming a dome reinforcing layer on the outer surface of the formed dome liner. Alternatively, a lid-shaped segment using a multi-load path structure may be used instead of the first dome segment 12 and second dome segment 13. [Explanation of symbols]

[0043] 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, 31: Pipe reinforcement layer, 32: First dome reinforcement layer, 33: Second dome reinforcement layer, 100, 200: Mandrel, 110: Shrink film, 120, 220: Fiber bundle, 321: Through hole

Claims

[Claim 1] A pipe division manufacturing step for producing a pipe division having a cylindrical pipe liner and a pipe reinforcing layer covering the outer surface of the pipe liner, The process of fabricating a dome segment, A joining step is to join the dome divisions produced in the dome division production step to both ends of the pipe division produced in the pipe division production step, A method for manufacturing a hydrogen tank, including The aforementioned pipe division process is as follows: A pipe liner forming step in which a mandrel is inserted through a tubular shrink film, and the mandrel and the shrink film are heated to bring them into close contact, thereby forming the pipe liner, A pipe reinforcement layer formation step involves winding multiple fiber bundles impregnated with resin around the outer surface of the formed pipe liner to form the pipe reinforcement layer, A drawing step is performed to remove the pipe liner and the pipe reinforcing layer formed on the mandrel from the mandrel, A method for manufacturing a hydrogen tank, characterized by having the following features.

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