JP2021167653A - Manufacturing method of high pressure tank - Google Patents

Abstract

To provide a manufacturing method of a high pressure tank having a leak port for releasing gas accumulated between a liner and a reinforcement layer.SOLUTION: A method of manufacturing a high pressure tank by impregnating a resin composition into a fiber layer of a preform provided with a fiber layer 12 on an outer periphery of a liner 11 includes: a process for placing the preform on a mold; and a process for supplying the resin composition to the fiber layer of the preform at an inner side of the mold. In the process for placing the preform on the mold, a clearance is formed between an outer peripheral surface of the preform and a surface of the mold, and a tip of a rod-like pin is disposed in the clearance in a projecting manner, and in the process for supplying the resin composition, the resin composition is supplied to the clearance and the fiber layer.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a method of manufacturing a high pressure tank reinforced with a resin-impregnated fiber layer.

For example, a high-pressure tank for a fuel cell vehicle has a liner that forms an internal space of the high-pressure tank, and is high because a reinforcing layer made of a fiber layer impregnated with a resin is arranged on the outer periphery of the liner. Achieves strength.

To manufacture such a high-pressure tank, a preform in which fibers are wound around a liner to form a fiber layer is prepared, and the fiber layer of the preform is impregnated with a resin before curing and cured to form an RTM as a reinforcing layer. There is a method called (Resin Fiber Molding).

Patent Document 1 discloses a method for manufacturing a high-pressure tank by RTM, in which a preform having a fiber layer formed on the outer surface of a liner forming an internal space of the high-pressure tank is arranged in a mold. The fiber layer is impregnated with the resin by injecting the resin toward the preform placed in the mold and rotating the preform in the circumferential direction around the center axis of the preform as the center of rotation. Is disclosed.

Patent Document 2 discloses that a hole is drilled in the reinforcing layer, and that the gas accumulated between the liner and the reinforcing layer is removed from the hole.

Patent Document 3 discloses that gas is injected between the reinforcing layer and the liner to form a plurality of vent holes in the reinforcing layer.

JP-A-2019-056415 JP-A-2009-243660 JP-A-2009-216133

For example, in a high-pressure tank that stores hydrogen, hydrogen that has permeated the liner may stay between the liner and the reinforcing layer. When the pressure in the high-pressure tank in this state is reduced, high-concentration hydrogen gas may be released from the vicinity of the base (see P in FIG. 5A).

The present disclosure has been made in view of these circumstances, and an object of the present disclosure is to provide a method for manufacturing a high-pressure tank having a leak port for discharging gas accumulated between a liner and a reinforcing layer.

The present application is a method for manufacturing a high-pressure tank by impregnating a fiber layer of a preform having a fiber layer formed on the outer periphery of a liner with a resin composition, in a step of arranging the preform in a mold and inside the mold. In the step of supplying the resin composition to the fiber layer of the preform and arranging the preform in the mold, a gap is provided between the outer peripheral surface of the preform and the surface of the mold, and the gap is provided. Disclosed is a method for manufacturing a high-pressure tank in which the tip of a rod-shaped pin is arranged so as to project and the resin composition is supplied to the gap and the fiber layer.

According to the manufacturing method of the present disclosure, the resin layer becomes thin at the place where the pin is arranged and becomes a leak port, so that hydrogen is sequentially released from the leak port, hydrogen is retained, and a high concentration is obtained from the base and the seal portion. It is possible to prevent the release of hydrogen.

FIG. 1A is an exploded view illustrating the mold 20 and the preform 10, a cut surface along the axis of the preform, and FIG. 1B is a cut surface orthogonal to the axis. FIG. 2A is a diagram illustrating one posture in which the preform 10 is arranged on the mold 20, a cut surface along the axis of the preform, and FIG. 2B is a cut surface orthogonal to the axis. FIG. 3A is an exploded view for explaining another posture of the mold 20, a cut surface along the axis of the preform, and FIG. 3B is a cut surface orthogonal to the axis. FIG. 4A is a diagram showing a posture in which the pressing pin member 22 is away from the preform 10, and FIG. 4B is a diagram showing a posture in which the pressing pin member 22 is approaching the preform 10. FIG. 5A is a diagram illustrating the configuration of the high-pressure tank 15, a cut surface along the axis of the high-pressure tank 15, and FIG. 5B is an enlarged portion of FIG. 5A, and the leak port 18a is shown. It is a figure explaining. FIG. 6 is a diagram illustrating a flow of the high pressure tank manufacturing method S10. 7 (a) and 7 (b) are diagrams for explaining the step of installation in the mold S11 and the step of degassing S12. FIG. 8 is a diagram illustrating a step S13 of supplying the resin composition. 9 (a) and 9 (b) are views for explaining the step S14 of changing to the tightened state.

[Preform, high pressure tank, impregnation device, etc.]
1 to 4 show schematically a preform 10 to be impregnated and a mold 20 for impregnating the preform 10 with a resin. In FIGS. 1 to 4 and the drawings shown thereafter, unless otherwise specified, the mold 20 is represented by a cut surface (hatched), and the preform 10 is represented by a surface rather than a cross section, and is inside the preform 10. The morphology is represented by a broken line.
FIG. 1 is an exploded view of the mold 20 and the preform 10. FIG. 1 (a) is a cut surface in the direction along the cylindrical axis of the preform 10, and FIG. 1 (b) is a cut surface orthogonal to the axis along the AA'of FIG. 1 (a). It is a cut surface.
FIG. 2 is a diagram showing one posture in which the preform 10 is installed on the mold 20. FIG. 2A is a cut surface in the direction along the cylindrical axis of the preform 10, and FIG. 2B is a cut surface orthogonal to the axis along the BB'of FIG. 2A. It is a cut surface.
FIG. 3 is an exploded view of the preform 10 and the mold 20, and is a diagram showing a posture in which the extrusion pin member 22, which will be described later, approaches the preform 10 side. FIG. 3A is a cut surface in the direction along the cylindrical axis of the preform 10, and FIG. 3B is a cut surface orthogonal to the axis along the CC'of FIG. 3A. It is a cut surface.
FIG. 4 is a view focusing on a portion of the extrusion pin member 22, FIG. 4A shows a posture in which the extrusion pin member 22 is separated from the preform 10, and FIG. 4B shows a posture in which the extrusion pin 22 is preformed. It is a posture approaching 10.

As can be seen from the following description, the present disclosure is a so-called RTM (Resin Transfer Molding) in which a fiber layer provided in a preform is impregnated with a resin composition and then cured to form a reinforcing layer. It is related to the high-pressure tank and its manufacturing method.

<Preform>
The preform is an intermediate member that eventually becomes a high-pressure tank. This form is a high-pressure tank for fuel cell vehicles among high-pressure tanks.
As can be seen from FIGS. 1 to 3, the preform 10 is configured to have at least a liner 11 and a fiber layer 12.

The liner 11 is a hollow tubular member that partitions the internal space of the high-pressure tank. The liner 11 may be made of a material that can hold what is stored in the internal space without leaking, and a known material can be used. For example, a nylon resin or a polyethylene-based synthetic resin can be used. It is made of stainless steel, metal such as aluminum, and the like. However, the present disclosure is based on the premise that, for example, if the stored substance is hydrogen or the like, it may permeate through the wall of the liner 11 and leak.
The thickness of the liner 11 is not particularly limited, but is preferably 0.5 mm to 1.0 mm.

The fiber layer 12 is a layer in which fibers are wound around the outer surface of the liner 11 over a number of layers until the fibers have a predetermined thickness. The thickness of the fiber layer 12 is determined by the required strength and is not particularly limited, but is set to a thickness of about 10 mm to 30 mm. In particular, in a high-pressure tank for a fuel cell vehicle, it is necessary to thicken the fiber layer in order to secure the strength, and the pressure at the time of impregnation becomes high from the viewpoint of impregnating the fiber layer with the resin.
Carbon fibers are used as the fibers of the fiber layer, and more specifically, it is a band-shaped carbon fiber bundle having a predetermined cross-sectional shape (for example, a rectangular cross section) as a bundle of carbon fibers. A fiber layer is formed by wrapping such a carbon fiber bundle around the outer surface of the liner 11. Further, the fibers (bundles) are wound around the outer surface of the liner 11 by, for example, a filament winding method or the like.

<High pressure tank>
The fiber layer 12 of the preform 10 as described above is impregnated with the resin composition and cured to form a reinforcing layer, which becomes the high-pressure tank 15. FIG. 5 (a) is a cross-sectional view taken along the axis of the high-pressure tank 15, and FIG. 5 (b) is an enlarged view of the portion surrounded by the dotted line in FIG. 5 (a) to explain the laminated structure. ..

As can be seen from FIG. 5B, in the reinforcing layer 16 laminated on the outer peripheral portion of the liner 11, the high-pressure tank 15 includes a layer 17 in which the fiber layer 12 is impregnated with resin, and the liner 11 among the layers 17. It has a resin-only layer 18 formed on the opposite side, and the layer 18 is provided with a plurality of leak ports 18a which are recesses.
According to such a high-pressure tank 15, as shown by the dotted arrow in FIG. 5B, the hydrogen that has permeated the liner 11 permeates the layers 17 and 18, and collects at the leak port 18a portion, and the leak. It is quickly discharged to the outside from the port 18a. This is because the reinforcing layer 16 is thinned at the portion of the leak port 18a, so that hydrogen is collected and discharged here. As a result, hydrogen that has permeated the liner 11 stays between the liner and the reinforcing layer, and when the pressure is reduced, the concentration is high from between the reinforcing layer 16 and the base 19 (the portion indicated by P in FIG. 5A). It is possible to suppress the release of hydrogen gas at once.

The leak port 18a may be provided by including a portion of the outer peripheral portion of the high-pressure tank 15 that is parallel to the axis of the high-pressure tank (the portion indicated by Q in FIG. 5A).
The shape of the leak port 18a is not particularly limited, but its plan view shape is preferably circular from the viewpoint of workability and low stress concentration. Further, since it is preferable that the thickness of the layer 18 at the portion where the leak port 18a is arranged is about 1 mm, if the thickness of the layer 18 is 2 mm or more and 5 mm or less, the depth of the leak port 18a is It is preferably 1 mm or more and 4 mm or less. The arrangement pitch of the leak port 18a is also not limited, but is preferably 100 mm or less.

<Type>
The mold 20 is a mold for impregnating the fiber layer 12 of the preform 10 with a resin, and is configured to have an upper mold 21 and a lower mold 25 in this embodiment. By overlapping the upper mold 21 and the lower mold 25, an internal space along the shape of the preform 10 is formed inside the mold 20. This internal space can form a closed space.

In this embodiment, the upper die 21 can move relative to the lower die 25 as shown by the straight arrows in FIGS. 2 (a) and 2 (b). As a result, the preform 10 can be installed in the mold 20 and separated from the mold 20 (released), moved so as to apply pressure to the preform 10, and the applied pressure is applied. It is also possible to move to unload the cargo. More specifically, the mold 20 can be in the open state, the tightened state, and the unloading state as follows.
The open state is a state in which the upper die 21 is completely separated from the lower die 25 and the upper surface of the lower die 25 is exposed and opened (not shown). In this state, the preform 10 is installed on the lower mold 25, and the preform 10 is separated (released) from the mold 20 after impregnation.
The tightened state is a state in which the preform 10 is installed in the mold 20, and the upper mold 21 and the lower mold 25 are completely connected and tightened (see FIGS. 2 and 9). Even in this tightened state, a slight gap is formed between the fiber layer 12 of the preform 10 before impregnation and the surfaces of the upper mold 21 and the lower mold 25. As will be described later, the gap is filled with the resin to form the resin-only layer 18 of the high-pressure tank 15. This gap is the same for the upper mold 21 and the preform 10 and the lower mold 25 and the preform 10.
The unloading state is a state in which the preform 10 is installed in the mold 20 and the upper mold 21 and the lower mold 25 are slightly separated from each other in the tightened state (see FIGS. 7 and 8). The unloading state is achieved, for example, by slightly raising the upper die 21 with respect to the tightened state. At this time, the gap between the upper mold 21 and the preform 10 is larger than the gap between the lower mold 25 and the preform 10. Even in this unloading state, the sealed state is maintained so that the resin composition for impregnation supplied inside does not leak out of the mold 20.

Further, in the present embodiment, the upper die 21 is provided with an extrusion pin member 22 that can move closer to and further away from the preform 10 to be installed. The extrusion pin member 22 forms a leak port 18a of the high pressure tank 15. In this embodiment, the extrusion pin member 22 has a plurality of pins 22a and a connecting member 22b.

The pin 22a is a pin for forming the leak port 18a in the reinforcing layer 16 of the high-pressure tank 15, and has a plan view shape of the leak port 18a (a shape in which the leak port 18a is viewed from a direction parallel to the depth direction of the leak port 18a). ) Is a rod-shaped member having a cross section corresponding to). The pin 22a extends in a direction orthogonal to the axis of the preform 10, penetrates the upper die 21, and is configured to reach the space in which the preform 10 is arranged. Then, a plurality of pins 22a are arranged along the axis of the preform 10.
As will be described later, the leak port 18a is formed by the end portion of the pin 22a on the preform 10 side.

The connecting member 22b is a member for connecting a plurality of pins 22a and moving the plurality of pins 22a at the same time. In the present embodiment, the connecting member 22b is a rod-shaped member extending parallel to the axis of the preform 10, and the end portions of a plurality of pins 22a (the end opposite to the end on the preform 10 side) are connected to the side surface thereof. Has been done.
The connecting member 22b is arranged in the space provided in the upper mold 21, and is installed in the mold 21 so that the connecting member 22b can move in the direction toward and away from the preform 10.

As can be clearly seen from FIGS. 1 to 4, such an extruded pin member 22 has an upper die 21 at a position where the connecting member 22b is moved away from the preform 10 and the tip (preform side end) of the pin 22a is at a position. The posture is such that the tip of the pin 22a protrudes from the surface of the upper die 21 toward the preform 10 at a position where the connecting member 22b moves so as to approach the preform 10.

Further, the mold 20 is provided with a flow path 20a and a flow path 20b communicating from the outside. Each of these channels is as follows.
The flow path 20a appears in FIGS. 1 (b), 2 (b), and 3 (b), and is a flow path for the resin composition. The resin composition before curing is supplied from the flow path 20a toward the fiber layer 12. Therefore, the flow path 20a reaches the fiber layer 12 of the preform 10 installed in the mold 20 from the outside of the mold 20. Further, in the present embodiment, the flow path 20a is provided in the upper mold 21.
The flow path 20b appears in FIGS. 1 (a), 2 (a), and 3 (a), and is a flow path for vacuum degassing. The fiber layer 12 and the air around it are evacuated from the flow path 20b. Therefore, the flow path 20b reaches the fiber layer 12 of the preform 10 installed in the mold 20 from the outside of the mold 20. Further, in the present embodiment, the flow path 20b is provided in the lower mold 25.

Further, the mold 20 is configured so that the temperature can be maintained at a desired temperature by a temperature control device (not shown).

The material used for the mold 20 is not particularly limited, but as usual, a metal is preferably used, and the mold 20 is a so-called mold.

<Others>
In the impregnation device, the corresponding equipment is arranged for each of the above-mentioned flow paths. That is, a device for supplying the resin composition to be impregnated is connected to the flow path 20a, and a vacuum pump is connected to the flow path 20b. The specific specifications of the device are not particularly limited for each, and known devices can be used.

[Manufacturing method of high pressure tank]
Next, a method of manufacturing a high-pressure tank will be described. The mold will be described with reference to the mold 20 described above. However, the present invention is not limited to the use of the mold 20.

FIG. 6 shows the flow of the high-pressure tank manufacturing method S10 according to one example. As can be seen from FIG. 6, the high-pressure tank manufacturing method S10 according to this embodiment includes a mold installation step S11, a degassing step S12, a resin composition supply step S13, and a process of changing to a tightened state S14. , The step S15 of stopping the supply of the resin composition and the step S16 of the mold release are included. Hereinafter, each step will be described.

<Process of installation on mold S11>
In the process of installation on the mold S11 (may be referred to as “process S11”), as shown in FIG. 7, the preform 10 is installed on the mold 20 to put the mold 20 in the unloading state. FIG. 7A is a view showing the entire mold 20 and the preform 10, and FIG. 7B is a view focusing on the periphery of the extrusion pin member 22.
That is, the preform 10 is installed inside the mold 20, and at this time, the upper mold 21 is placed so that the gap between the upper mold 21 and the preform 10 is larger than the gap between the lower mold 25 and the preform 10. Arrange so as to be separated from the lower mold 25.

At this time, the extrusion pin member 22 is in a posture of projecting from the surface of the mold 21 into the gap so that the pin 22a approaches the preform 10. In this posture, it is preferable that the tip of the pin 22a is positioned so as to have a slight gap (δ in FIG. 7B) without touching the fiber layer 12. The size δ of the gap is not particularly limited, but is preferably about 1 mm. Such an arrangement of the pins 22a prevents the pins 22a from damaging the fibers of the fiber layer 12, disturbs the flow of the resin composition in the fiber layer 12, and causes the generation of air bubbles. Can be prevented.

More specifically, in the step S11 of the present embodiment, the preform 10 is transferred to the lower mold 25 in a state where the upper mold 21 is completely separated from the lower mold 25 and the upper surface of the lower mold 25 is completely exposed and opened. Install. Next, the upper mold 21 is arranged so as to cover the lower mold 25 and the preform 10 installed here. Then, the upper mold 21 is arranged in an unloaded state so as to be separated from the lower mold 25 as described above. At this time, the extrusion pin member 22 moves so that the pin 22a approaches the preform 10 by moving the connecting portion 22b, and the tip of the pin 22a projects into the gap between the upper mold 21 and the fiber layer 12. Arrange as follows.

<Deaeration process S12>
In the degassing step S12 (may be referred to as “step S12”), after obtaining the states of the preform 10 and the mold 20 by the step S11, vacuum degassing is performed to remove the air on the outer peripheral portion of the preform 10. Remove.

More specifically, in this embodiment, after the states of the preform 10 and the mold 20 are obtained in step S11, degassing is performed from the flow path 20b from the flow path 20b as shown in FIG. 7 (a) by a vacuum pump.

By vacuum degassing, the impregnated resin composition can be more smoothly permeated into the fiber layer. Further, this also makes it possible to suppress the entrainment of air bubbles in the impregnated resin.

<Process of supplying resin composition S13>
In step S13 of supplying the resin composition (may be referred to as “step S13”), the fiber layer of the preform 10 in which the resin composition before curing is arranged in the mold 20 in the state obtained in step S12. Supply for 12 units.

More specifically, in this embodiment, as shown in FIG. 8, the resin composition before curing is supplied to the flow path 20a from the device that supplies the resin composition, and the resin composition is the fiber of the preform 10. It reaches the outer periphery of the layer 12. FIG. 8 is a view showing a cross section of D-D'of FIG. 7 (a).
This resin composition is supplied with the pressure required for impregnation, whereby the resin composition permeates the fiber layer 12 and fills the space between the mold 21 and the fiber layer 12 (the portion where the pin 22a protrudes).
At this time, the mold 20 is in the state obtained in the step S12, a gap is provided between the upper mold 21 and the preform 10, the pressure on the preform 10 is suppressed, and when the resin composition flows. Resistance can be suppressed. Therefore, the supplied resin composition is smoothly filled with high uniformity over the entire space between the upper mold 21 and the preform 10.

The resin composition is not particularly limited as long as it can reach and permeate the fiber layer in a fluid state and then cure by some method to increase the strength of the fiber layer. Examples thereof include thermosetting resins that are cured by heat, and examples thereof include amine-based or anhydride-based curing accelerators, epoxy resins containing rubber-based reinforcing agents, and unsaturated polyester resins. In addition to this, a resin composition in which an epoxy resin is used as a main component and cured by mixing a curing agent with the epoxy resin can be mentioned. According to this, the resin composition, which is a mixture, reaches and permeates the fiber layer between the time when the main agent and the curing agent are mixed and the time when the curing agent is cured, so that the resin composition is automatically cured.

<Step S14 for changing to the tightened state>
In step S14 (sometimes referred to as “step S14”) of changing to the tightened state, the upper die 21 and the lower die 25 are moved so as to be close to each other, and the die 20 is tightened as shown in FIG. And. FIG. 9A is a view showing the entire mold 20 and the preform 10, and FIG. 9B is a view focusing on the periphery of the extrusion pin member 22.
As described above, even in this tightened state, a slight gap is formed between the fiber layer 12 of the preform 10 before impregnation and the surfaces of the upper mold 21 and the lower mold 25. This gap becomes the resin-only layer 18 of the high-pressure tank 15 shown in FIG. 5 (b).

Further, in this step S14, as can be seen from FIG. 9B, it is preferable that the distance δ of the gap between the tip of the pin 22a of the extrusion pin member 22 and the fiber layer 12 is maintained at the same distance as in step S12. As a result, the leak port 18a (see FIG. 5B) can be formed in the resin-only layer 18.

By this step S14, the pressure received by the resin composition from the mold 20 is increased, the impregnation of the resin composition is promoted, and the resin-only layer 18 and the leak port 18a are formed together.
In this embodiment, as shown by a straight arrow in FIG. 9A, the upper die 21 is brought closer to the lower die 25. Further, the extrusion pin member 22 maintains its position by moving so as to be relatively raised with respect to the upper die 21 as the upper die 21 moves.
In the step S14, the supply of the resin composition is still maintained.

<Step S15 of Stopping Supply of Resin Composition>
In step S15 (sometimes referred to as “step S15”) of stopping the supply of the resin composition, when the fiber layer 12 is sufficiently impregnated with the resin composition in step S14 and the desired supply amount is satisfied, Stop the supply of the resin composition. Then, it waits for the resin composition to cure.

<Release process S16>
In the mold release step S16 (may be referred to as “step S16”), the resin composition is cured in the step S15, and the resin-impregnated preform 10 is separated from the mold 20. ..
In this embodiment, the upper mold 21 of the mold 20 is separated from the lower mold 25 and is opened to release the mold.

[Effects, etc.]
A high-pressure tank 15 can be obtained by a manufacturing method including each of the above steps and a mold for that purpose. At this time, the leak port 18a can be efficiently and easily formed by the pressing pin member 22. Further, if the tip of the pin 22a is arranged apart from the fiber layer 12, it is possible to prevent the pin 22a from damaging the fiber layer 12 or entraining air bubbles in the fiber layer 12 when the resin composition is supplied.
As described above, according to the present disclosure, it is possible to efficiently form the leak port 18a, and to manufacture a high-quality impregnation and a high-pressure tank.

10 Preform 11 Liner 12 Fiber layer 15 High pressure tank 16 Reinforcing layer 17 (Fiber impregnated with resin) Layer 18 (Resin only) layer 18a Leak port 20 type 21 Upper type 22 Extrusion pin member 25 Lower type

Claims (1)

A method for manufacturing a high-pressure tank by impregnating the fiber layer of a preform having a fiber layer formed on the outer periphery of a liner with a resin composition.
The process of arranging the preform in the mold and
A step of supplying the resin composition to the fiber layer of the preform inside the mold.
In the step of arranging the preform in the mold,
A gap is provided between the outer peripheral surface of the preform and the surface of the mold, and the tip of the rod-shaped pin is arranged so as to protrude into the gap.
In the step of supplying the resin composition, the resin composition is supplied to the gap and the fiber layer.
Manufacturing method of high pressure tank.

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