JP7655069B2 - Manufacturing method of high pressure tank - Google Patents

Description

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

In high-pressure tanks formed by winding fiber-reinforced resin around a liner, the problem of clouding due to gas accumulating in the surface resin layer after the liner hardens is a problem. Patent Document 1 discloses a technique in which a first resin layer with a large breaking strain is formed on the liner, and then a second resin layer with a small breaking strain is formed on top of the first resin layer. This ensures gas barrier properties through the first resin layer, while generating fine cracks in the second resin layer, suppressing clouding of the surface.

JP 2017-72244 A

However, with the technology of Patent Document 1, resins with different properties must be prepared in advance for the first resin layer and the second resin layer to be impregnated into the fiber bundle, and switching between them during the manufacturing process is time-consuming.

The method for manufacturing a high-pressure tank according to the present invention is a method for manufacturing a high-pressure tank in which a liner is covered with a reinforcing layer, and includes a step of preparing a liner, and a step of forming a reinforcing layer by winding the fiber bundles impregnated with resin in multiple layers around the liner while adding a reinforcing material that reinforces the reinforcing layer to the fiber bundles, and is characterized in that, in the step of forming the reinforcing layer, the amount of reinforcing material added to the fiber bundles forming the outermost layer is less than the amount of reinforcing material added to the fiber bundles forming layers inside the outermost layer, or is zero.

According to the present invention, the breaking strain of the reinforcing layer is controlled by the amount of reinforcing material added, thereby making the breaking strain of the outermost layer relatively low. This makes it possible to easily manufacture tanks that can suppress the occurrence of cloudy areas on the tank surface.

In a more preferred embodiment, the fiber bundle is made of the same material from the start to the end of winding it around the liner, and the type of resin impregnated into the fiber bundle may also be the same from the start to the end of winding it around the liner.

When changing the fiber bundle or the resin material to be impregnated between the start and end of winding, it is conceivable that the time and effort required to take measures such as improving the device so that the fiber bundle can be changed or replacing the impregnation tank to change the resin may be required. In contrast, with this configuration, it is possible to provide a tank that more easily prevents gas from accumulating under the surface resin layer of the reinforcing layer without taking the measures described above.

In a more preferred embodiment, the reinforcing material is a curing agent that hardens the resin impregnated into the fiber bundles, and when the curing agent is added to the fiber bundles in the process of forming the reinforcing layer, the amount of curing agent added to the fiber bundles forming the outermost layer may be less than the amount of curing agent added to the fiber bundles forming the inner layers.

If the fiber bundle is impregnated with a resin containing a curing agent prior to the process of forming the reinforcing layer, the curing reaction will proceed before the winding, shortening the usable time (pot life). In contrast, with this configuration, the impregnated resin does not react with the curing agent prior to the process of forming the reinforcing layer, making it possible to extend the usable time (pot life).

In a more preferred embodiment, the hardener may be a solid hardener.

If the curing agent is liquid, it will flow over the surface of the wound fiber bundle (the tank surface during winding) before reacting with the impregnated resin, making it difficult to add the curing agent evenly to the resin on the tank surface. In contrast, with this configuration, a solid curing agent is less likely to flow over the tank surface, making it easier to disperse it evenly over the tank surface and add it to the resin.

In a more preferred embodiment, when adding a solid hardener to the fiber bundle in the process of forming the reinforcing layer, the solid hardener may be mixed with the same type of resin as the resin impregnated into the fiber bundle.

When only a solid curing agent is added, the reaction of the solid component proceeds only at the interface of the solid surface, so the reaction rate at the start of the curing reaction is slow and the curing time is long. In contrast, with this configuration, the curing time can be shortened by mixing the solid curing agent with the same type of resin as the resin impregnated in the fiber bundle before addition. This is because the reaction activity of the solid curing agent surface is increased in advance by reacting with the mixed resin, thereby increasing the start speed of the curing reaction with the resin impregnated in the fiber bundle. Furthermore, since a solid curing agent is used, the pot life of the premixed mixture is longer than when a liquid curing agent is premixed with the resin and added.

In a more preferred embodiment, the reinforcing material may be an elastic filler.

When a thermoplastic resin is used, it is not possible to change the breaking strain by changing the amount of hardener added. In contrast, this configuration has the effect of making it easy to change the breaking strain by changing the amount of elastic filler added.

In a more preferred embodiment, when adding elastic filler to the fiber bundles in the process of forming the reinforcing layer, the amount of elastic filler added to the fiber bundles forming the outermost layer may be set to 0.

If elastic filler is added to all layers, the breaking strain of the tank increases, but the breaking strain also increases in the surface resin layer, making it difficult for cracks to occur. In contrast, with this configuration, adding elastic filler to layers other than the outermost layer ensures breaking strain for the entire tank, while not adding it to the outermost layer makes it easier to induce cracks in the surface resin layer after hardening.

In a more preferred embodiment, in the process of forming the reinforcing layer, the fiber bundle may be wound around a roller before winding the fiber bundle around the liner and before adding the reinforcing material to the fiber bundle, to even out the resin impregnated in the fiber bundle.

When the reinforcing material is solid, when smoothing the resin impregnated into the fiber side, the solid reinforcing material may get between the roller and the fiber bundle, making it difficult to smooth out, and there is a risk of damaging the fiber bundle or roller. In contrast, with this configuration, the solid reinforcing material is added after the roller, which reduces the above-mentioned risk.

In a more preferred embodiment, the liner has a cylindrical body and hemispherical side ends at both ends of the body, and when adding reinforcing material to the fiber bundle in the process of forming the reinforcing layer, the amount of reinforcing material added to the fiber bundle that wraps around the side ends may be greater than the amount of reinforcing material added to the fiber bundle that wraps around the body.

According to this configuration, the dome portion contains a larger amount of reinforcing material than the cylindrical portion, and therefore the durability of the tank is improved when the tank falls and lands on the ground first with the dome portion.

FIG. 2 is a diagram showing the appearance of the high-pressure tank according to the first embodiment. 1 is a flowchart of a method for manufacturing a high-pressure tank according to a first embodiment; 2 is a cross-sectional view of the high-pressure tank shown in FIG. 1 along line AA. An illustration of the cloudiness of a high-pressure tank. An explanatory diagram of the abnormal noise caused by cloudiness in the high-pressure tank. 5A to 5C are diagrams illustrating a winding step, which is part of the step of forming a reinforcing layer, in the method for manufacturing the high-pressure tank according to the first embodiment. 1 is a diagram of a liner prepared in a process of preparing a liner. An explanatory diagram of hoop winding. An explanatory diagram of helical winding.

First Embodiment
Hereinafter, the first embodiment will be described with reference to the drawings.
1 shows the appearance of a high-pressure tank 1 manufactured by the manufacturing method of a high-pressure tank according to the first embodiment. An example of an application of such a high-pressure tank 1 is a hydrogen tank for storing hydrogen gas used as a reactant gas in a fuel cell. A variety of applications of the hydrogen tank are possible, such as a fuel cell vehicle and an emergency power source using a fuel cell. In addition, the object to be stored in the high-pressure tank is not limited to hydrogen gas, and any fluid, such as other gases or liquids, can be stored.

The high-pressure tank 1 has a cylindrical portion 11 and dome portions 12 formed on both sides of the cylindrical portion 11, and the overall shape of the high-pressure tank 1 is approximately ellipsoidal. Both the cylindrical portion 11 and the dome portion 12 are covered with a reinforcing layer 30 composed of a fiber bundle PF containing resin P. Metal nozzles 41, 42 are formed on both ends of the high-pressure tank 1. One of the nozzles 41, 42, for example the nozzle 41, becomes a fluid path when a valve or the like is connected when supplying the fluid stored inside the high-pressure tank 1 to the outside. In this case, the other nozzle 42 generally plays the role of a holding portion that holds the high-pressure tank 1 when a reinforcing layer is formed on the high-pressure tank 1. The other nozzle 42 is not an essential component for the function of the high-pressure tank 1.

Figure 2 shows the steps of the method for manufacturing the high-pressure tank 1 according to the first embodiment. This embodiment is composed of two steps. First, step S11 is performed to prepare the liner 20. Then, step S12 is performed to form the reinforcing layer 30.

In step S11 of preparing the liner 20, the liner 20 is first prepared from a material that is impermeable to the fluid trapped inside the high-pressure tank 1. Examples of materials for the liner 20 include PP (polypropylene), polyethylene, and nylon. The liner 20 may also be formed by mixing a gas-impermeable material such as a hydrogen storage alloy into such a resin. The liner 20 has a generally ellipsoidal shape with hemispherical side ends 22 at both ends of a cylindrical body 21, and forms the basis of the shape of the high-pressure tank 1. The liner 20 also has nozzles 41 and 42 at both ends. In this embodiment, the liner 20 is generally ellipsoidal, but is not limited to this as long as the steps described below can be performed. For example, a generally spherical shape is possible. In this case, the shape of the high-pressure tank itself is also likely to be generally spherical.

In the process S11 of preparing the liner, the nozzles 41 and 42 are held to hold the liner 20 rotatably around the axis C of the liner 20. In this embodiment, the liner 20 has nozzles 41 and 42 on both ends, but it is also possible to have only the nozzle 41, which serves as a fluid flow path. However, by having the nozzles 41 and 42 on both sides, it is possible to suppress deflection due to a force perpendicular to the axis C. This makes it possible to wind the fiber bundle PF precisely when winding it around the liner 20, as described below.

Next, step S12 of forming the reinforcing layer 30 will be described. In this embodiment, step S12 of forming the reinforcing layer 30 is roughly divided into the following two steps. In the first step, the fiber bundle PF impregnated with the resin P is wound around the liner 20. In the second step, the wound fiber bundle PF is hardened to form the reinforcing layer 30. Note that, although step S12 of forming the reinforcing layer 30 in this embodiment is divided into the above-mentioned two steps, this is not a required configuration. For example, the hardening of the resin P may be progressed while the fiber bundle PF is being wound.

Among the process S12 for forming the reinforcing layer 30, the process for hardening the fiber bundle PF will be described in detail. In this embodiment, a thermosetting resin is used as the resin P, and in the process for hardening the fiber bundle PF, the high-pressure tank 1 is placed in a heat hardening oven and heated. Note that it is not essential that the process for hardening the fiber bundle PF be provided separately from the process for winding the fiber bundle PF. For example, heating may be performed using a heater that partially heats the fiber bundle PF at the same time as winding it. It is also not essential to use a thermosetting resin for the resin P. For example, an ultraviolet-curable resin may be used and hardened by irradiating ultraviolet light.

Using FIG. 3, the surface resin layer 32 formed on the outermost surface of the reinforcing layer 30 in the high-pressure tank 1 after the fiber bundle PF has hardened will be described. The surface resin layer 32 is a layer formed when a part of the resin P seeps out of the reinforcing layer 30 from the gaps in the fiber bundle PF under the influence of the tension applied during winding during the transitional stage in which the resin P impregnated in the fiber bundle PF hardens. The resin P that seeps out of the reinforcing layer 30 accumulates on the outermost surface of the reinforcing layer 30 and hardens. As a result, the surface resin layer 32 is formed on the outermost surface of the reinforcing layer 30. For this reason, the surface resin layer 32 does not contain the fiber bundle F, and in this respect, it differs from the reinforcing layer 30. The resin that forms the surface resin layer 32 is mainly the resin that is impregnated in the fiber bundle PF that forms the outermost layer of the reinforcing layer 30 before hardening.

The clouding phenomenon caused by the surface resin layer 32 will be explained using Figures 4A and 4B. The surface resin layer 32 has higher gas barrier properties than the reinforcing layer 30. As a result, as shown in Figure 4A, the gas stored in the high-pressure tank 1 that has permeated the liner 20 also permeates the reinforcing layer 30, forming a retention area G directly below the surface resin layer 32. When the high-pressure tank 1 is viewed from the outside, this retention area G is visible as cloudy. If the amount of permeating gas increases and the internal pressure of the retention area G rises to a certain level, it will burst when it exceeds the strength of the surface resin layer 32, as shown in Figure 4B. At that time, it will be recognized as an abnormal noise from the outside. This abnormal noise is about 80 to 100 dB, but it is desirable to suppress it.

The present invention prevents the formation of stagnation portions G by winding the fiber bundle PF around the liner 20, which is part of process S12 for forming the reinforcing layer 30, as described below. This suppresses the occurrence of cloudiness and abnormal noise.

Figure 5 shows the process of winding the fiber bundle PF around the liner 20, which is part of step S12 of forming the reinforcing layer 30 in the manufacturing method of the high-pressure tank 1 according to the first embodiment. In this embodiment, first, in the impregnation tank 60 of Figure 5, a fiber bundle PF impregnated with resin P is produced. Specifically, resin (monomer resin) P that reacts with a curing agent and hardens is contained in the impregnation tank 60, and while transporting the fiber bundle F supplied from the bobbin 50, the fiber bundle F is immersed in the resin P of the impregnation layer 60, thereby impregnating the fiber bundle F with the resin P. In this way, a fiber bundle PF impregnated with resin P can be obtained.

The fiber bundle F is a reinforcing fiber for improving the strength of the reinforcing layer 30, and is, for example, made of carbon fiber. An example of the resin P that reacts with the curing agent and hardens is epoxy resin. The curing agent also functions as a reinforcing material for strengthening the reinforcing layer 30. An example of the curing agent is an amine-based curing agent, such as dicyandiamide. Other combinations may be used as long as the curing agent and the resin react and harden. In this embodiment, no curing agent is added to the resin P contained in the impregnation tank 60. In this embodiment, the fiber bundle PF is created in the impregnation tank 60, but this is not a required configuration. For example, a bobbin that can supply the fiber bundle PF that has been impregnated with the resin P in advance may be used instead of the bobbin 50.

Next, the fiber bundle PF created in this embodiment is supplied to the liner 20 after the resin P is leveled by the roller 70. The roller 70 has various roles, such as removing excess resin P from the fiber bundle PF, unifying the direction of the fiber bundle PF, and adjusting the tension of the fiber bundle PF. This roller may be provided with multiple rollers, or may be provided with a single roller. Also, the roller 70 may not be provided.

In this embodiment, the hardener is a solid hardener R. The resin P impregnated into the fiber bundle F reacts with the solid hardener R and hardens. When the fiber bundle PF impregnated with the resin P is wound around the liner 20, the fiber bundle PF is wound while adding the solid hardener R from the hardener supply device 80 to the fiber bundle PF. If the resin P containing the solid hardener R is impregnated into the fiber bundle PF before winding, the hardening reaction is accelerated before winding, and the usable time (pot life) is shortened. On the other hand, according to this configuration, the usable time (pot life) can be extended by adding the solid hardener R to the resin impregnated during winding. In this embodiment, the hardener supply device 80 is located near the liner 20, and supplies the solid hardener R toward the surface of the liner 20 and adds it to the fiber bundle PF. When adding, the solid hardener R may be dropped vertically downward as shown in the figure, or the solid hardener R may be sprayed from another direction to add the solid hardener R to the fiber bundle PF. Furthermore, instead of adding the solid hardener R to the fiber bundle PF after the fiber bundle PF reaches the liner 20, the solid hardener R may be added to the fiber bundle PF before the fiber bundle PF reaches the liner 20. When adding the solid hardener R to the fiber bundle PF before the fiber bundle PF reaches the liner 20, the supply device 80 may be provided, for example, at a supply port (generally called an Aikuchi) that supplies the fiber bundle PF to the liner 20 (not shown). In addition, the solid hardener R may be added to the fiber bundle PF at multiple locations simultaneously using multiple hardener supply devices 80. In either case, the solid hardener R reacts with the resin P to harden the resin P in the process of forming the reinforcing layer 30.

Next, the winding will be described with reference to Figures 6A to 6C. The winding is performed using hoop winding or helical winding, which are used in the general FW method. Hoop winding is a winding method mainly used to increase the strength of the body part 21 of the liner 20. For the liner 20 prepared as shown in Figure 6A, the fiber bundle PF is wound around the liner 20 so that the angle θ1 between the fiber bundle PF impregnated with resin P and the axis C of the high-pressure tank 1 is approximately right angles, as shown in Figure 6B. On the other hand, helical winding is a winding method mainly used to increase the strength of the side end part 22 of the liner 20. For the liner 20 prepared as shown in Figure 6A, the fiber bundle PF impregnated with resin P is wound around the side end part 22 on both sides of the high-pressure tank 1 so that it reciprocates as shown in Figure 6C. Unlike hoop winding, the angle θ2 between the fiber bundle PF and the axis C of the high-pressure tank 1 is generally about 50° or less. In addition, the angle θ1 of the hoop winding is generally almost a right angle, but for some purpose, it is also possible to use a high-angle helical winding with an angle of about 80° instead of the hoop winding. Hoop winding and helical winding are generally performed after the helical winding, but in this embodiment, the order is random, and the winding may be performed in one way, then the other way, and then the winding may be performed again.

During winding, in both hoop winding and helical winding, layers are stacked to form the reinforcing layer 30. The "layer" refers to the hoop layer and the helical layer, and the "layer addition amount" refers specifically to the mass of solid hardener R added per unit volume of the portion of each hoop layer and each helical layer that is wound around the body part 21 of the liner 20. In this embodiment, when forming the reinforcing layer 30, after the area that each layer is intended to cover is covered, the next outer layer is wound. The determination of whether the area that each layer is intended to cover has been covered may be made based on whether a predetermined time has elapsed since the start of winding, or the relative positional relationship between the liner 20 and the hardener supply device 80 may be used. The outer layer here refers to the layer on the radially outer side of the body part 21 of the liner 20.

The method of supplying the solid hardener R is to supply the solid hardener R from the hardener supply device 80 so that the amount of solid hardener R added is uniform within the same layer. In addition, a set amount is supplied for each layer, and in this embodiment, the amount added gradually decreases toward the outer side of the layer, but the amount added may be changed in stages rather than gradually. In either case, the amount of solid hardener R added to the outermost layer is the smallest compared to the inner layers, and the breaking strain is relatively small.

In this embodiment, the amount of solid hardener R added is uniform within the same layer, but as in the modified example described below, the solid hardener R may be added in a biased amount within the same layer. The mass per unit volume calculated by dividing the total mass of the solid hardener R added to each layer by the volume of the layer is the amount added to that layer.

According to the embodiment described above, it is possible to easily manufacture a high-pressure tank 1 in which the breaking strain of the outermost layer is smaller than that of the inner layer without changing the material of the fiber bundle or the resin to be impregnated from the start to the end of winding. As a result, for example, during a pressure test performed before shipping the high-pressure tank 1, a strain larger than the breaking strain of the surface resin layer after the reinforcing layer 30 has hardened can be applied, thereby causing cracks to occur in the surface resin layer. The occurrence of cracks can prevent gas that has leaked from inside the liner and permeated the reinforcing layer from accumulating under the surface resin layer. In other words, this embodiment makes it possible to easily manufacture a high-pressure tank 1 that suppresses the occurrence of cloudiness on the surface of the tank.

<Modification of the first embodiment>
Here, a modification of the first embodiment will be described.

In the first embodiment, cracks are induced during a pressure test, but the amount of solid hardener R added may be set so that cracks occur in the surface resin layer when the high-pressure tank 1 is used under normal conditions (e.g., tank internal pressure of 70 MPa). In addition, the amount of solid hardener R added may be set experimentally by conducting multiple experiments.

In the first embodiment, a solid hardener R is used as the hardener used as a reinforcing material, but a liquid hardener may also be used.

However, if the hardener is liquid, it will flow off the tank surface before reacting with the resin P impregnated into the fiber bundles, making it difficult to add it evenly. In contrast, a solid hardener is less likely to flow off the tank surface, making it easier to add it evenly.

The solid hardener R may be added as a hardener in a mixed state with the same type of resin P as the resin P impregnated in the fiber bundle PF. If the solid hardener R is added directly to the fiber bundle PF impregnated with the resin P, the reaction of the solid components proceeds only at the interface of the solid surface, so the reaction rate at the start of the hardening reaction is slow and the hardening time is long. In contrast, if the solid hardener R is mixed with the same type of resin P as the resin P impregnated in the fiber bundle PF before addition, as in this configuration, the hardening time can be shortened. This is because the reaction activity of the surface of the solid hardener R is increased in advance by the reaction with the mixed resin P, which increases the start speed of the hardening reaction with the resin P impregnated in the fiber bundle PF. In addition, compared to the case where a liquid hardener is mixed with the resin in advance, the use of a solid hardener has the effect of providing a longer pot life for the mixture that has been mixed in advance.

Second Embodiment
Next, a second embodiment will be described. The second embodiment has a similar configuration to the first embodiment, but differs from the first embodiment mainly in the type of reinforcing material.

In this embodiment, an elastic filler R' is used as a reinforcing material. The elastic filler R' differs from the solid hardener R used in the first embodiment in that it does not undergo a hardening reaction with the resin P impregnated in the impregnation tank 60. Since it does not undergo a hardening reaction, the elastic filler R' remains inside the reinforcing layer 30 as a tangible object even after hardening. Since the elastic filler R' has elasticity, even when a force is applied to the reinforcing layer 30 and stress occurs, it elastically deforms and relieves the generated stress. This makes it possible to increase the fatigue strength of the reinforcing layer 30. Examples of the elastic filler R' include alkaline rubber.

In this embodiment, it is possible to use a thermoplastic resin or the like as the resin P. If a resin that does not undergo a chemical reaction when cured is used as the resin P to be impregnated into the resin-impregnated fiber bundle PF, a hardener cannot be used as the reinforcing material. In other words, if a thermoplastic resin or the like is used, it is not possible to induce cracks in the surface resin layer by changing the amount of hardener added as in the first embodiment. In contrast, if an elastic filler R' is used as the reinforcing material, it is possible to induce cracks by controlling the breaking strain of each layer of the reinforcing layer by changing the amount of elastic filler R' added.

In addition, in this embodiment, it is not necessary to add elastic filler R' to the outermost layer. This is because in the first embodiment, it was necessary to add solid hardener R, which is a reinforcing material, to harden resin P. In this embodiment, elastic filler R' is not essential for hardening resin P, so the tank can be manufactured without adding elastic filler R' to the outermost layer.

If elastic filler R' is added to all layers, the breaking strain of the tank increases, but the breaking strain also increases in the surface resin layer of the high-pressure tank 1 after it has hardened, making it difficult for cracks to occur. On the other hand, with this configuration, by not adding elastic filler R' to the outermost layer, cracks are more likely to occur in the surface resin layer of the high-pressure tank 1 after it has hardened.

<Other embodiments>
Other elements that can be modified in common to the above-described embodiments include the following: The following modification examples can be implemented in combination with each other to the extent that there is no technical contradiction.

In each of the above embodiments, the hardener R is added after the resin P impregnated in the fiber bundle PF is leveled by the roller 70, but this is not a required configuration. If reinforcing material is supplied to the fiber bundle PF, the reinforcing material may be added before the roller 70.

However, if the hardener R is added before the resin P impregnated in the fiber bundle PF is leveled by the roller 70, the resin may react with the hardener and begin a hardening reaction, causing the resin to adhere to the roller 70. This may cause the resin to harden slowly on the roller 70, resulting in the resin sticking to the roller 70 and causing problems with the functionality of the roller 70.

Furthermore, if the reinforcing material is a solid, for example a solid hardener R or an elastic filler R', the following problems may occur. These problems include the fiber bundle PF being cut and the cut fiber bundle PF becoming entangled in the roller 70, damaging the roller, etc. This is thought to be because, when the solid hardener is between the fiber bundle PF and the roller 70 on the roller 70, the fiber bundle PF comes into contact with the corners of the surface of the solid hardener, and tension is applied there, causing a stress concentration that exceeds the breaking stress of the fiber bundle PF.

The occurrence of these problems can be prevented by adding reinforcing material after leveling the resin P impregnated into the fiber bundle PF with the roller 70 as in each of the above embodiments.

In each of the above embodiments, the amount of reinforcing material R added is uniform within the same layer, but this is not a required configuration. A larger amount may be added in some parts of the same layer. For example, the amount of reinforcing material added in the part where the side end portion 22 of the liner 20 is wound may be greater than the amount of reinforcing material added in the part where the body portion 21 is wound.

This configuration improves the durability of the tank when it falls and lands on the ground with the dome section 12 first. This is because, due to the shape of the high-pressure tank 1, it is more likely that the dome section 12 will hit the ground first than the cylindrical section 11 when it falls. It also takes into consideration that, when the tank falls on the cylindrical section 11, the contact area is large, whereas when the tank falls on the dome section 12, the contact area is small, and the pressure when it hits the ground is likely to be high.

In the above embodiments, the relationship of the amount of additive between layers other than the outermost layer is not specified, but the difference in the amount of additive between adjacent layers may be equal to or less than a predetermined value. In general, if the strength is discontinuous, stress concentration occurs in the discontinuous portion when stress occurs. In contrast, with this configuration, the strength change inside the reinforcing layer is continuous, so that the occurrence of stress concentration can be suppressed. The predetermined value is within an acceptable range for a continuous change in the amount of additive, and can be set to, for example, 10% of the amount of additive in the layer with the maximum amount of additive.

Reference Signs List 1 High pressure tank 20 Liner 30 Reinforcing layer 50 Bobbin 60 Impregnation tank 70 Roller 80 Reinforcement supply device F Fiber bundle P Resin PF Fiber bundle impregnated with resin R Solid hardener

Claims (5)

A method for manufacturing a high-pressure tank having a liner covered with a reinforcing layer, comprising the steps of:
providing the liner;
forming the reinforcing layer by winding the fiber bundle impregnated with resin around the liner in multiple layers while adding a reinforcing material for reinforcing the reinforcing layer to the fiber bundle;
having
In the step of forming the reinforcing layer, when adding the reinforcing material to the fiber bundles, the amount of the reinforcing material added to the fiber bundle forming the outermost layer is set to be less than the amount of the reinforcing material added to the fiber bundle forming a layer on an inner side than the outermost layer, or to be zero ;
The fiber bundle is made of the same material from the start of winding the fiber bundle around the liner to the end of winding, and the type of resin impregnated into the fiber bundle is also the same from the start of winding the fiber bundle around the liner to the end of winding,
The reinforcing material is a curing agent that cures the resin impregnated in the fiber bundle,
In the step of forming the reinforcing layer, when adding the hardener to the fiber bundles, the amount of the hardener added to the fiber bundles forming the outermost layer is made smaller than the amount of the hardener added to the fiber bundles forming the inner layer,
the curing agent is a solid curing agent;
In the step of forming the reinforcing layer, when the solid hardener is added to the fiber bundle, the solid hardener is mixed with the same type of resin as the resin impregnated into the fiber bundle.
A method for manufacturing a high-pressure tank. A method for manufacturing a high-pressure tank having a liner covered with a reinforcing layer, comprising the steps of:
providing the liner;
forming the reinforcing layer by winding the fiber bundle impregnated with resin around the liner in multiple layers while adding a reinforcing material for reinforcing the reinforcing layer to the fiber bundle;
having
In the step of forming the reinforcing layer, when adding the reinforcing material to the fiber bundles, the amount of the reinforcing material added to the fiber bundle forming the outermost layer is set to be less than the amount of the reinforcing material added to the fiber bundle forming a layer on an inner side than the outermost layer, or to be zero ;
The fiber bundle is made of the same material from the start of winding the fiber bundle around the liner to the end of winding, and the type of resin impregnated into the fiber bundle is also the same from the start of winding the fiber bundle around the liner to the end of winding,
The resin is a thermoplastic resin, and the reinforcing material is an elastic filler.
A method for manufacturing a high-pressure tank. 3. The method for manufacturing a high-pressure tank according to claim 2 , wherein, in the step of forming the reinforcing layer, when the elastic filler is added to the fiber bundles, an amount of the elastic filler added to the fiber bundle constituting the outermost layer is set to 0. 4. The method for manufacturing a high-pressure tank according to claim 1, wherein in the step of forming the reinforcing layer, the fiber bundle is wound around a roller before winding the fiber bundle around the liner and before adding the reinforcing material to the fiber bundle , and the resin impregnated in the fiber bundle is uniformed. The liner has a cylindrical body and hemispherical side ends at both ends of the body,
5. The method for manufacturing a high-pressure tank according to claim 1, wherein in the step of forming the reinforcing layer, when adding the reinforcing material to the fiber bundle, an amount of the reinforcing material added to the fiber bundle wound around the side end portion is made greater than an amount of the reinforcing material added to the fiber bundle wound around the body portion .

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