阅读说明：本技术 高压罐的制造方法 (Method for manufacturing high-pressure tank ) 是由 上田直树 于 2020-03-06 设计创作，主要内容包括：本发明提供一种高压罐的制造方法,能够抑制高压罐的品质降低并且抑制由气体压力导致表面树脂层破坏。高压罐(10)的制造方法包括：在树脂制的内衬(11)的外表面形成未固化的纤维增强树脂层(12)的缠绕工序S1；以第1温度对未固化的纤维增强树脂层(12)进行局部加热,由此从未固化的纤维增强树脂层(12)渗出热固性树脂而形成表面树脂层(13),并且以产生裂缝(13a)的方式使表面树脂层(13)固化的第1加热工序S2；以及在第1加热工序S2之后,以低于第1温度的第2温度加热高压罐(10)整体,由此使纤维增强树脂层(12)整体和从纤维增强树脂层(12)整体渗出的表面树脂层(13)整体固化,得到在表面树脂层(13)局部产生了裂缝(13a)的高压罐(10)的第2加热工序S3。(The invention provides a method for manufacturing a high-pressure tank, which can inhibit the quality reduction of the high-pressure tank and inhibit the surface resin layer from being damaged due to the gas pressure. A method for manufacturing a high-pressure tank (10) includes: a winding step S1 for forming an uncured fiber-reinforced resin layer (12) on the outer surface of a resin liner (11); a 1 st heating step S2 in which the uncured fiber-reinforced resin layer (12) is locally heated at a 1 st temperature, whereby thermosetting resin is exuded from the uncured fiber-reinforced resin layer (12) to form a surface resin layer (13), and the surface resin layer (13) is cured so that cracks (13a) are generated; and a 2 nd heating step S3 of heating the entire autoclave (10) at a 2 nd temperature lower than the 1 st temperature after the 1 st heating step S2 to cure the entire fiber-reinforced resin layer (12) and the entire surface resin layer (13) that has oozed from the entire fiber-reinforced resin layer (12), thereby obtaining the autoclave (10) in which cracks (13a) are locally generated in the surface resin layer (13).)

1. A method for manufacturing a high-pressure tank including a resin liner, a fiber-reinforced resin layer covering the outer surface of the liner, and a surface resin layer covering the outer surface of the fiber-reinforced resin layer,

the manufacturing method is characterized by comprising:

forming an uncured fiber reinforced resin layer on the outer surface of the liner by winding a fiber bundle impregnated with a thermosetting resin around the outer surface of the liner;

a 1 st heating step of forming the surface resin layer by locally heating the uncured fiber-reinforced resin layer at a 1 st temperature to exude the thermosetting resin from a heated region of the uncured fiber-reinforced resin layer, and curing the surface resin layer so that cracks are generated in the surface resin layer; and

and a 2 nd heating step of heating the entire autoclave at a 2 nd temperature lower than the 1 st temperature after the 1 st heating step to cure the entire fiber-reinforced resin layer and the entire surface resin layer that has oozed out from the entire fiber-reinforced resin layer, thereby obtaining an autoclave in which the cracks are locally generated in the surface resin layer.

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

in the 1 st heating step, the locally heated region includes a winding end of the fiber bundle.

3. The method of manufacturing a high-pressure tank according to claim 1 or 2,

in the first heating step 1, the uncured fiber-reinforced resin layer is heated by locally blowing hot air.

Technical Field

The present invention relates to a method for manufacturing a high-pressure tank including a fiber-reinforced resin layer formed by winding a fiber bundle impregnated with a thermosetting resin around a resin liner.

Background

Conventionally, as a high-pressure tank (high-pressure gas storage container) for storing and supplying hydrogen or the like, a tank including a tank main body and a metal mouth (japanese language: mouth) portion attached to an opening end portion in a longitudinal direction of the tank main body is known. The tank main body includes, for example, a liner for holding hydrogen gas in an airtight manner and a Fiber-reinforced resin layer whose outer peripheral surface is reinforced by winding a Fiber bundle made of CFRP (Carbon Fiber reinforced plastics) or the like.

As a method for manufacturing a high-pressure tank, for example, a method is known in which an uncured fiber-reinforced resin layer is formed by winding fiber bundles around the outer surface of an inner liner by a filament winding method (hereinafter, also referred to as an "FW method"), and then the fiber-reinforced resin layer is heated and cured. When the uncured fiber-reinforced resin layer is heat cured, the thermosetting resin bleeds out from the uncured fiber-reinforced resin layer to form a surface resin layer covering the fiber-reinforced resin layer.

However, since the resin liner does not contain a substance that completely blocks gas, the gas filled in the liner permeates through the liner over time. Since the surface resin layer has a gas barrier function (gas barrier property), the gas that has permeated through the liner is blocked by the surface resin layer made of only the resin. When the gas penetrating through the liner is blocked by the surface resin layer and the gas pressure in the fiber-reinforced resin layer reaches a critical point, the surface resin layer is broken and the gas is released at a burst. In this case, although there is no problem in terms of safety in terms of the amount of gas released, abnormal noise is generated due to the destruction of the surface resin layer.

To overcome such a problem, for example, patent document 1 discloses a high-pressure tank in which the entire uncured surface resin layer is applied with a solvent and infiltrated, and then subjected to a heating treatment to form the entire surface resin layer into a porous structure. In this high-pressure tank, the gas that has passed through the liner passes through the surface resin layer, and therefore the surface resin layer is not destroyed and the gas is not released at once.

Prior art documents

Patent document 1: japanese patent laid-open publication No. 2011-144860

Disclosure of Invention

However, in the high-pressure tank of patent document 1, since the solvent is applied to the uncured surface resin layer, the quality of the high-pressure tank is degraded when the solvent penetrates into the fiber-reinforced resin layer.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a high-pressure tank, which can suppress a deterioration in quality of the high-pressure tank and also suppress a breakage of a surface resin layer due to a gas pressure.

A method for manufacturing a high-pressure tank according to the present invention includes a resin liner, a fiber-reinforced resin layer covering an outer surface of the liner, and a surface resin layer covering an outer surface of the fiber-reinforced resin layer, and includes: forming an uncured fiber reinforced resin layer on the outer surface of the liner by winding a fiber bundle impregnated with a thermosetting resin around the outer surface of the liner; a 1 st heating step of forming the surface resin layer by locally heating the uncured fiber-reinforced resin layer at a 1 st temperature to exude the thermosetting resin from a heated region of the uncured fiber-reinforced resin layer, and curing the surface resin layer so that cracks are generated in the surface resin layer; and a 2 nd heating step of heating the entire high-pressure tank at a 2 nd temperature lower than the 1 st temperature after the 1 st heating step to cure the entire fiber-reinforced resin layer and the entire surface resin layer that has oozed out from the entire fiber-reinforced resin layer, thereby obtaining a high-pressure tank in which the cracks are locally generated in the surface resin layer.

The method for manufacturing a high-pressure tank according to the present invention includes a 1 st heating step of forming the surface resin layer by locally heating the uncured fiber-reinforced resin layer at a 1 st temperature by bleeding out the thermosetting resin from a heated region of the uncured fiber-reinforced resin layer and curing the surface resin layer so that cracks are generated in the surface resin layer, and a 2 nd heating step of heating the entire high-pressure tank to obtain a high-pressure tank in which cracks are locally generated in the surface resin layer. This makes it possible to release the gas that has permeated the liner (gas in the fiber-reinforced resin layer) to the outside through the cracks in the surface resin layer, and therefore, it is possible to suppress the surface resin layer from being broken by the gas pressure in the fiber-reinforced resin layer and the gas from being released at once. Therefore, generation of abnormal noise due to the destruction of the surface resin layer can be suppressed.

In addition, since it is not necessary to apply a solvent to the uncured surface resin layer, the solvent does not penetrate into the fiber-reinforced resin layer, and the quality of the high-pressure tank is not deteriorated.

In the method for manufacturing a high-pressure tank, in the first heating step 1, a region to be locally heated preferably includes a winding end of the fiber bundle. According to such a technical configuration, it is not necessary to provide a step for fixing the winding end of the fiber bundle in addition to the 1 st heating step, and the increase in the manufacturing time can be suppressed. Further, since the winding end is cracked not only in the longitudinal direction but also in the width direction (the width direction of the fiber bundle), the gas in the fiber-reinforced resin layer can be reliably released to the outside through the cracks in the surface resin layer.

In the method for manufacturing a high-pressure tank, it is preferable that the uncured fiber-reinforced resin layer is heated by locally blowing hot air in the first heating step 1. According to such a technical configuration, the fiber-reinforced resin layer can be easily heated locally.

According to the present invention, it is possible to provide a method for manufacturing a high-pressure tank, which can suppress a reduction in quality of the high-pressure tank and can suppress a breakage of a surface resin layer due to a gas pressure.

Drawings

Fig. 1 is a partial sectional view showing the structure of a high-pressure tank manufactured by the manufacturing method according to the embodiment of the present invention.

Fig. 2 is a perspective view showing the structure of a high-pressure tank manufactured by the manufacturing method according to the embodiment of the present invention, and is a view showing a fiber-reinforced resin layer formed by circumferentially winding the outer peripheral portion.

Fig. 3 is an enlarged view of a portion a of fig. 1.

Fig. 4 is a flowchart illustrating a method of manufacturing a high-pressure tank according to an embodiment of the present invention.

Fig. 5 is a view for explaining the 1 st heating step of the method for manufacturing a high-pressure tank according to the embodiment of the present invention.

Fig. 6 is an enlarged view showing the structure of the periphery of the surface resin layer of the high-pressure tank manufactured by the manufacturing method according to the embodiment.

Fig. 7 is an enlarged view showing the structure of the periphery of the surface resin layer of the high-pressure tank manufactured by the manufacturing method according to the comparative example.

Description of the reference numerals

10: high-pressure tank, 11: inner liner, 12: fiber-reinforced resin layer, 13: surface resin layer, 13 a: crack, F: fiber bundle, Fa: winding end, S1: winding step (step of forming uncured fiber-reinforced resin layer), S2: 1 st heating step, S3: 2 nd heating step

Detailed Description

Hereinafter, a method for manufacturing the high-pressure tank 10 according to an embodiment of the present invention will be described with reference to the drawings. Hereinafter, the high-pressure tank 10 will be described as a tank filled with high-pressure hydrogen gas mounted on a fuel cell vehicle, but may be applied to other applications. The gas that can be filled in the high-pressure tank 10 is not limited to high-pressure hydrogen.

First, the structure of the high-pressure tank 10 will be described. As shown in fig. 1, the high-pressure tank 10 is a high-pressure gas storage container having a substantially cylindrical shape with dome-shaped ends. The high-pressure tank 10 includes a liner 11 having gas barrier properties, a fiber-reinforced resin layer 12, and a surface resin layer 13. The high-pressure tank 10 has openings at both ends, and a metal port 14 is attached to one opening and an end flange (end boss)16 is attached to the other opening.

The liner 11 is a resin member forming a housing space 17 for filling high-pressure hydrogen gas. Typically, the liner 11 is composed of a thermoplastic resin that can be processed into a substantially cylindrical shape or the like. The resin constituting the liner 11 is preferably a resin having good processability and good performance of holding hydrogen gas in the housing space 17 and gas barrier properties. Examples of such resins include thermoplastic resins such as polyesters, polyamides, polyethylene, and ethylene-vinyl alcohol copolymer resins (EVOH).

The liner 11 has a substantially cylindrical shape having dome portions at both ends as described above. An opening is formed in each dome portion of the liner 11, and a metal port 14 and an end flange 16 are provided in each opening. The fiber reinforced resin layer 12 and the surface resin layer 13 are formed along the outer surface of the liner 11, and thus the shape of the liner 11 determines the shape of the high-pressure tank 10.

The metal opening 14 is an outlet for hydrogen gas filled in the housing space 17. The metal port 14 may be provided with a valve 15, for example, and may be formed with a groove, not shown, that fits in the valve 15. As the metal opening 14, a metal opening formed by processing a metal material such as an aluminum alloy into a predetermined shape can be used.

The end flange 16 is a member provided at a dome portion on the opposite side of the metal port 14, and is a member to be attached to a shaft for rotating the liner 11 when the fiber-reinforced resin layer 12 is formed. Further, the shaft is mounted not only to the end flange 16 but also to the metal mouth 14. The end flange 16 may be made of a metal material such as an aluminum alloy, as in the case of the metal port 14.

The fiber-reinforced resin layer 12 is a layer that covers the outer surface of the liner 11, and has a function of reinforcing the liner 11 to improve the mechanical strength such as the rigidity and pressure resistance of the high-pressure tank 10. The fiber-reinforced resin layer 12 is composed of a thermosetting resin and reinforcing fibers. As the thermosetting resin, thermosetting resins such as phenol resin, melamine resin, urea resin, and epoxy resin are preferably used, and particularly, epoxy resin is preferably used from the viewpoint of mechanical strength and the like. As the reinforcing fiber, glass fiber, aramid fiber, boron fiber, carbon fiber, and the like can be used, and carbon fiber is preferably used particularly from the viewpoint of lightweight property, mechanical strength, and the like.

The epoxy resin is generally a resin obtained by mixing a prepolymer such as a copolymer of bisphenol a and epichlorohydrin with a curing agent such as polyamine and thermally curing the mixture. The epoxy resin has fluidity in an uncured state, and forms a strong cross-linked structure after heat curing.

The fiber-reinforced resin layer 12 is formed by winding a bundle of fibers (e.g., carbon fibers) impregnated with an uncured resin (e.g., epoxy resin) around the outer surface of the liner 11 and curing the resin. For example, a shaft is attached to the metal port 14 and the end flange 16 of the liner 11, the liner 11 is rotatably supported, and the fiber bundle impregnated with the resin is wound by spiral winding and hoop winding while rotating. The resin component is cured by heating at the curing temperature of the resin. By using both the spiral winding and the hoop winding, the mechanical strength such as pressure resistance can be ensured in the axial direction and the radial direction of the high-pressure tank 10.

The surface resin layer 13 is a layer in which uncured epoxy resin of the fiber-reinforced resin layer 12 is exuded to the outside. The surface resin layer 13 is a layer made of a resin formed only by the resin component being pushed outward when the fiber-reinforced resin layer 12 is heated.

In the present embodiment, as shown in fig. 2 and 3, the surface resin layer 13 is provided with a crack region R having a plurality of cracks 13a penetrating the surface resin layer 13 in the thickness direction. The crack region R is, for example, a region having a diameter of about 1.5 to 4 times the width of the fiber bundle F. That is, the cracks 13a are not formed in the entire surface resin layer 13, but are formed in part of the surface resin layer 13. In addition, the surface resin layer 13 of the crack region R is provided with 1-3, for example.

In the present embodiment, the slit region R includes at least the winding end Fa of the fiber bundle F. Further, the slit 13a is formed along the edge of the fiber bundle F. Therefore, the slit 13a is formed along the length direction of the fiber bundle F (the circumferential direction of the liner 11) in the vicinity of the winding end Fa of the fiber bundle F, and is also formed along the width direction of the fiber bundle F.

The surface resin layer 13 having the cracks 13a is highly permeable to gas, and therefore can release hydrogen gas that has permeated the liner 11 to the outside without being blocked. Therefore, the surface resin layer 13 is not broken by the increase in the air pressure in the fiber-reinforced resin layer 12.

Next, a method for manufacturing the high-pressure tank 10 according to an embodiment of the present invention will be described. Fig. 4 is a flowchart showing a method of manufacturing the high-pressure tank 10, and shows a step after providing the fiber-reinforced resin layer 12 on the outer surface of the liner 11 to which the metal port 14 and the end flange 16 are attached. As shown in fig. 4, the method of manufacturing the high-pressure tank 10 includes a winding process S1, a 1 st heating process S2, and a 2 nd heating process S3. The steps are performed in sequence. The winding step S1 is an example of the "step of forming an uncured fiber-reinforced resin layer" in the present invention.

In the winding step S1, the shaft as the rotating mechanism is attached to the opening 14 and the end flange 16 of the liner 11, and the liner 11 is rotatably supported. While the liner 11 is rotated, the fiber bundle F impregnated with the uncured thermosetting resin is wound so as to cover the outer surface of the liner 11. The winding method includes so-called spiral winding in which winding is performed at an angle different from an axis line CL (see fig. 2) of the liner 11 by several tens of degrees, and so-called hoop winding in which winding is performed at an angle close to a right angle to the axis line CL (see fig. 2) of the liner 11. Preferably, both the spiral winding and the hoop winding are alternately performed. Through this step, the uncured fiber reinforced resin layer 12 is formed on the outer surface of the liner 11.

In the 1 st heating step S2, the uncured fiber reinforced resin layer 12 is locally heated at the 1 st temperature higher than the curing temperature of the thermosetting resin (here, epoxy resin). At this time, in a heated region (hereinafter also referred to as a heating region) of the fiber-reinforced resin layer 12, the thermosetting resin is temporarily softened and oozes out of the fiber-reinforced resin layer 12 to form the surface resin layer 13. The 1 st heating step S2 is performed without rotating the liner 11, unlike the winding step S1. The heating region corresponds to the above-described crack region R.

In the present embodiment, the 1 st temperature is preferably 140 to 240 ℃ higher than the 2 nd temperature (temperature at which the thermosetting resin is cured) described later. As a result, as will be described later, the temperature difference when the surface resin layer 13 is cooled from the 1 st temperature to the predetermined temperature increases, and the load applied to the surface resin layer 13 increases, so that the surface resin layer 13 is likely to generate the crack 13 a.

In addition, when the uncured fiber-reinforced resin layer 12 is locally heated, it is preferable that the uncured fiber-reinforced resin layer is heated to the 1 st temperature at a temperature increase rate of, for example, 5.3 ℃/sec or more and is kept at the 1 st temperature for the 1 st predetermined time (for example, several minutes). Thereby, in the heating zone, the glass transition temperature of the thermosetting resin becomes a predetermined value or more, and the curing of the thermosetting resin is completed.

Then, by blowing cooling wind to the fiber reinforced resin layer 12 and the surface resin layer 13, the fiber reinforced resin layer 12 and the surface resin layer 13 are cooled forcibly from the 1 st temperature to a predetermined temperature (for example, a temperature lower than the glass transition temperature (for example, several tens degrees)), and are rapidly cooled. Thereby, in the heating region, a plurality of cracks 13a penetrating the surface resin layer 13 in the thickness direction are formed in the surface resin layer 13. Further, since the surface resin layer 13 is rapidly cooled by the forced cooling, the load applied to the surface resin layer 13 increases, and the surface resin layer 13 is more likely to generate the crack 13 a. The cooling rate when rapidly cooling the fiber-reinforced resin layer 12 and the surface resin layer 13 is, for example, preferably 12.5 ℃/sec or more.

In the present embodiment, as shown in fig. 5, the heating region when locally heating the uncured fiber-reinforced resin layer 12 includes the winding end Fa of the fiber bundle F. By blowing hot air from the air blowing device 20 so as to press the winding end Fa of the fiber bundle F toward the liner 11 side, the region including the winding end Fa is heated. Thus, since the winding end Fa of the fiber bundle F can be fixed to the surface of the fiber reinforced resin layer 12 in the first heating step S2, a step of fixing the winding end Fa of the fiber bundle F by a manual operation is not required. Further, since the curing of the thermosetting resin of the winding terminal Fa is completed, the situation in which the thermosetting resin of the winding terminal Fa softens and the winding terminal Fa is peeled off does not occur in the 2 nd heating step S3.

In addition, in the fiber reinforced resin layer 12, a step is formed along the edge of the fiber bundle F, and therefore stress concentrates on the edge of the fiber bundle F upon cooling. Therefore, the slit 13a is formed along the edge of the fiber bundle F. That is, the slits 13a are formed along the longitudinal direction of the fiber bundle F (the circumferential direction of the liner 11). In the present embodiment, since the heating region includes the winding end Fa of the fiber bundle F, the slit 13a is also formed along the width direction of the fiber bundle F.

In addition, since the diameter of the heating region in locally heating the uncured fiber-reinforced resin layer 12 is equal to or larger than the width of the fiber bundle F (for example, about 1.5 to 4 times), at least one edge of the winding end Fa passes through the heating region. Therefore, 1 or more cracks 13a are formed in the heating zone.

In the 2 nd heating step S3, the entire high-pressure tank 10 is heated at the 2 nd temperature (the temperature at which the thermosetting resin is cured or slightly higher than the curing temperature) lower than the 1 st temperature. As a result, the thermosetting resin softens and bleeds out from the fiber-reinforced resin layer 12 to form the surface resin layer 13 in the entire high-pressure tank 10 (except for the heating region of the 1 st heating step S2). The 2 nd heating step S3 is performed in a state where the liner 11 is rotated, unlike the 1 st heating step S2. In the 2 nd heating step S2, the entire high-pressure tank 10 is heated by, for example, induction heating.

When the entire high-pressure tank 10 is heated, the high-pressure tank is heated to the 2 nd temperature and is maintained at the 2 nd temperature for a 2 nd predetermined time (for example, several tens of minutes to several hundreds of minutes) longer than the 1 st predetermined time. Thereby, in the entirety of the fiber reinforced resin layer 12 and the surface resin layer 13, the glass transition temperature of the thermosetting resin becomes a predetermined value or more, and the curing of the thermosetting resin is completed. The fiber-reinforced resin layer 12 and the surface resin layer 13 are slowly cooled (at a cooling rate lower than the cooling rate) to the glass transition temperature of the thermosetting resin, and then cooled by cooling air.

As described above, the high-pressure tank 10 in which the cracks 13a were locally generated in the surface resin layer 13 was obtained.

Further, if the fiber-reinforced resin layer 12 is heated in the 2 nd heating step S3, voids (not shown) are generated in the fiber-reinforced resin layer 12 due to the air that enters the gaps between the fiber bundles F in the winding step S1 and the gas generated from the thermosetting resin. Then, if the liner 11 is filled with high-pressure gas during a pressure resistance test of the high-pressure tank 10 or the like, the fiber-reinforced resin layer 12 receives a load, and a crack 12a is generated in the fiber-reinforced resin layer 12 from the void (see fig. 3). Voids are likely to be generated along the edges of the fiber bundle F, and therefore the cracks 12a are also likely to be generated along the edges of the fiber bundle F.

As described above, the present embodiment includes: a 1 st heating step S2 of forming a surface resin layer 13 by locally heating the uncured fiber-reinforced resin layer 12 at a 1 st temperature, thereby bleeding out the thermosetting resin from a heated region of the uncured fiber-reinforced resin layer 12 and curing the surface resin layer 13 so that cracks 13a are generated in the surface resin layer 13; the 2 nd heating step S3 of heating the entire high-pressure tank 10 to obtain the high-pressure tank 10 in which the cracks 13a are locally generated in the surface resin layer 13. This allows the gas that has permeated the liner 11 (gas in the fiber-reinforced resin layer 12) to be released to the outside through the cracks 13a in the surface resin layer 13, and therefore, it is possible to suppress the release of the gas at a time due to the destruction of the surface resin layer 13 by the gas pressure in the fiber-reinforced resin layer 12. Therefore, generation of abnormal noise due to breakage of the surface resin layer 13 can be suppressed.

In addition, since it is not necessary to apply a solvent to the uncured surface resin layer 13, the solvent does not penetrate into the fiber-reinforced resin layer 12, which leads to a reduction in the quality of the high-pressure tank 10. Further, since the cracks 13a in the surface resin layer 13 are formed only locally, the strength of the high-pressure tank 10 is hardly reduced.

In addition, as described above, in the 1 st heating step S2, the locally heated region includes the winding end Fa of the fiber bundle F. This eliminates the need for a step of fixing the winding end Fa of the fiber bundle F, other than the 1 st heating step S2, and therefore, the manufacturing time can be kept from increasing. Further, since the crack 13a is generated not only in the longitudinal direction but also in the width direction of the fiber bundle F at the winding end Fa, the crack 12a of the fiber-reinforced resin layer 12 and the crack 13a of the surface resin layer 13 can be reliably intersected (connected). Therefore, the gas in the fiber-reinforced resin layer 12 can be reliably released to the outside through the cracks 13a in the surface resin layer 13.

In addition, as described above, in the 1 st heating step S2, the uncured fiber reinforced resin layer 12 is heated by locally blowing hot air. This makes it possible to easily heat the fiber-reinforced resin layer 12 locally.

Next, the effects of the present invention will be described in more detail with reference to examples.

(examples)