Manufacturing method of high pressure tank

Abstract

To easily produce a tank that can suppress the formation of cloudy areas on the surface of the tank.SOLUTION: A method for manufacturing a high-pressure tank in which a liner is covered with a reinforcing layer, includes the steps of preparing the liner, and adding a reinforcing material to reinforce the reinforcing layer to a resin-impregnated fiber bundle while winding the fiber bundle around the liner in multiple layers to form the reinforcing layer. In the step of forming the reinforcing layer, in adding the reinforcing material to the fiber bundle, the amount of the reinforcing material added to the fiber bundle forming the outermost layer is 0 or less than the amount of the reinforcing material added to the fiber bundle forming the layer inside the outermost layer.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a high-pressure tank. [Background technology]

[0002] 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 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-72244 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in 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, which requires the time-consuming task of switching between them during the manufacturing process. [Means for solving the problem]

[0005] The method for manufacturing a high-pressure tank according to the present invention is a method for manufacturing a high-pressure tank having a liner covered with a reinforcing layer, and includes the steps of preparing a liner, and forming a reinforcing layer by winding a resin-impregnated fiber bundle in multiple layers around the liner while adding a reinforcing material that strengthens the reinforcing layer to the fiber bundle, and is characterized in that, in the step of forming the reinforcing layer, the amount of reinforcing material added to the fiber bundle forming the outermost layer is less than the amount of reinforcing material added to the fiber bundle forming a layer further inside than the outermost layer, or is zero.

[0006] 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 a tank that can suppress the occurrence of cloudy parts on the surface of the tank.

[0007] In a more preferred embodiment, 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 may also be the same from the start of winding the fiber bundle around the liner to the end of winding.

[0008] When changing the material of the fiber bundle or the resin to be impregnated between the start and end of winding, it is considered that the time and effort required to improve the device so that the fiber bundle can be changed, to replace the impregnation tank to change the resin, etc. 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 above-mentioned measures.

[0009] In a more preferred embodiment, the reinforcing material is a curing agent that hardens the resin impregnated into the fiber bundles, and when adding the curing agent 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.

[0010] If the fiber bundle is impregnated with a resin containing a curing agent prior to the step of forming the reinforcing layer, the curing reaction will proceed prior to winding, shortening the pot life. In contrast, with this configuration, the impregnated resin does not react with the curing agent prior to the step of forming the reinforcing layer, making it possible to extend the pot life.

[0011] In a more preferred embodiment, the hardener may be a solid hardener.

[0012] 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, the solid curing agent is less likely to flow over the tank surface, making it easier to distribute it evenly over the tank surface and add it to the resin.

[0013] In a more preferred embodiment, when the solid curing agent is added to the fiber bundle in the step of forming the reinforcing layer, the solid curing agent may be mixed with the same type of resin as the resin impregnated into the fiber bundle.

[0014] 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, according to this configuration, the solid curing agent is mixed with the same type of resin as the resin impregnated in the fiber bundle before addition, so the curing time can be shortened. This is because the reaction activity of the solid curing agent surface can be 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.

[0015] In a more preferred embodiment, the reinforcing material may be an elastic filler.

[0016] When a thermoplastic resin is used as the resin, it is not possible to change the breaking strain by changing the amount of hardener added. In contrast, with this configuration, the breaking strain can be easily changed by changing the amount of elastic filler added.

[0017] As a more preferred embodiment, when the elastic filler is added to the fiber bundles in the step of forming the reinforcing layer, the amount of the elastic filler added to the fiber bundles forming the outermost layer may be set to 0.

[0018] If elastic filler is added to all layers, the breaking strain of the tank increases, but the breaking strain of the surface resin layer also increases, making it difficult for cracks to occur. On the other hand, with this configuration, by adding elastic filler to layers other than the outermost layer, the breaking strain of the tank as a whole is ensured, while by not adding it to the outermost layer, cracks are more likely to be induced in the surface resin layer after hardening.

[0019] In a more preferred embodiment, in the step 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 reinforcing material to the fiber bundle, to uniformize the resin impregnated into the fiber bundle.

[0020] When the reinforcing material is solid, when the resin impregnated in the fiber side is leveled, the solid reinforcing material gets between the roller and the fiber bundle, making it difficult to level, and there is a risk of damaging the fiber bundle or the roller. In contrast, with this configuration, the solid reinforcing material is added after the roller, which suppresses the above-mentioned risk.

[0021] In a more preferred embodiment, the liner has a cylindrical body portion and hemispherical side ends at both ends of the body portion, 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 wound around the side ends may be greater than the amount of reinforcing material added to the fiber bundle wound around the body portion.

[0022] 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. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a diagram showing the appearance of the high-pressure tank according to the first embodiment. [Diagram 2] 1 is a flow chart of a method for manufacturing a high-pressure tank according to a first embodiment; [Diagram 3] 2 is a cross-sectional view taken along line AA of the high-pressure tank shown in FIG. 1. [Figure 4A] An illustration of the cloudiness of a high-pressure tank. [Figure 4B] An explanatory diagram of the abnormal noise caused by cloudiness in the high-pressure tank. [Diagram 5] 5A to 5C are views showing 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. [Figure 6A] 1 is a diagram of a liner prepared in the process of preparing a liner. [Figure 6B] An explanatory diagram of hoop winding. [Figure 6C] An explanatory diagram of helical winding. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] <First embodiment> The first embodiment will be described below with reference to the drawings. 1 shows the appearance of a high-pressure tank 1 manufactured by the manufacturing method for 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 for a fuel cell. A variety of applications are possible for hydrogen tanks, such as fuel cell vehicles and emergency power sources using fuel cells. In addition, the object stored in the high-pressure tank is not limited to hydrogen gas, and any fluid, such as other gases or liquids, can be stored.

[0025] 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 a substantially ellipsoidal shape. Both the cylindrical portion 11 and the dome portion 12 are covered with a reinforcing layer 30 composed of a fiber bundle PF containing a resin P. Metallic nozzles 41 and 42 are formed on both ends of the high-pressure tank 1. One of the nozzles 41 and 42, for example the nozzle 41, becomes a fluid path by connecting a valve or the like when supplying the fluid stored inside the high-pressure tank 1 to the outside. In this case, the other nozzle 42 generally plays a role as 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.

[0026] 2 is a diagram showing steps of a method for manufacturing the high-pressure tank 1 according to the first embodiment. This embodiment is composed of two steps. First, step S11 of preparing the liner 20 is performed. Then, step S12 of forming the reinforcing layer 30 is performed.

[0027] In step S11 of preparing the liner 20, the liner 20 is first prepared from a material that has a property of not allowing the fluid trapped inside the high-pressure tank 1 to pass through. Examples of the material of the liner 20 include PP (polypropylene), polyethylene, and nylon. The liner 20 may also be formed by mixing such a resin with a gas-impermeable material such as a hydrogen storage alloy. The liner 20 has a substantially ellipsoidal shape with hemispherical side ends 22 at both ends of a cylindrical body portion 21, and serves as the basis for 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 substantially ellipsoidal, but is not limited to this as long as the steps described below can be performed. For example, a substantially spherical shape is possible. In this case, the shape of the high-pressure tank itself is also likely to be substantially spherical.

[0028] In step S11 of preparing a 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 the 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 bending due to a force perpendicular to the axis C. This makes it possible to wind the fiber bundle PF accurately when winding it around the liner 20 as described below.

[0029] 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 cured 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 an essential configuration. For example, the curing of the resin P may proceed while the fiber bundle PF is being wound.

[0030] 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 furnace and heated. 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 as the resin P. For example, an ultraviolet-curable resin may be used and hardened by irradiating ultraviolet light.

[0031] With reference to 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 is 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 in the transitional stage of hardening of the resin P impregnated in the fiber bundle PF. 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 is different 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 constitutes the outermost layer of the reinforcing layer 30 before hardening.

[0032] The clouding phenomenon caused by the surface resin layer 32 will be described with reference to Figs. 4A and 4B. The surface resin layer 32 has a higher gas barrier property than the reinforcing layer 30. As a result, as shown in Fig. 4A, the gas stored in the high-pressure tank 1 that has permeated the liner 20 also permeates the reinforcing layer 30 to form a retention portion G directly below the surface resin layer 32. When the high-pressure tank 1 is viewed from the outside, this retention portion G is visually recognized as clouding. When the amount of permeating gas increases and the internal pressure of the retention portion G rises to a certain level, it will burst when it exceeds the strength of the surface resin layer 32 as shown in Fig. 4B. At that time, it is recognized as an abnormal sound from the outside. This abnormal sound is about 80 to 100 dB, but it is desirable to suppress it.

[0033] In the present invention, the step of winding the fiber bundle PF around the liner 20, which is part of the step S12 for forming the reinforcing layer 30, is a step described below, thereby preventing the formation of the stagnation portion G. This suppresses the generation of cloudiness and abnormal noise.

[0034] 5 shows a step of winding the fiber bundle PF around the liner 20, which is part of step S12 for forming the reinforcing layer 30 in the manufacturing method of the high-pressure tank 1 according to the first embodiment. In this embodiment, first, a fiber bundle PF impregnated with a resin P is produced in an impregnation tank 60 shown in FIG. 5. Specifically, a resin (monomer resin) P that reacts with a curing agent and hardens is contained in the impregnation tank 60, and while conveying 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, the fiber bundle PF impregnated with the resin P can be obtained.

[0035] The fiber bundle F is a reinforcing fiber for improving the strength of the reinforcing layer 30, and for example, carbon fiber is used. 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 of these 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 an essential 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.

[0036] Next, the fiber bundle PF produced 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 a single roller. Also, the roller 70 may not be provided.

[0037] In this embodiment, the curing agent is a solid curing agent R. The resin P impregnated into the fiber bundle F reacts with the solid curing agent 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 curing agent R from the curing agent supply device 80 to the fiber bundle PF. If the resin P containing the solid curing agent R is impregnated into the fiber bundle PF before winding, the curing 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 curing agent R to the resin impregnated during winding. In this embodiment, the curing agent supply device 80 is located near the liner 20, and supplies the solid curing agent R toward the surface of the liner 20 and adds it to the fiber bundle PF. When adding, the solid curing agent R may be dropped vertically downward as shown in the figure, or the solid curing agent R may be sprayed from another direction and added to the fiber bundle PF. Furthermore, instead of adding the solid curing agent R to the fiber bundle PF after the fiber bundle PF reaches the liner 20, the solid curing agent R may be added to the fiber bundle PF before the fiber bundle PF reaches the liner 20. When the solid curing agent R is added 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). Also, the solid curing agent R may be added to the fiber bundle PF at multiple locations simultaneously using multiple curing agent supply devices 80. In either case, the solid curing agent R reacts with the resin P so that the resin P can be cured in the process of forming the reinforcing layer 30.

[0038] Next, the winding will be described with reference to Figs. 6A to 6C. The winding is performed using hoop winding, helical winding, or the like used in the general FW method. Hoop winding is a winding method used mainly to increase the strength of the body part 21 of the liner 20. The fiber bundle PF is wound around the liner 20 prepared as shown in Fig. 6A so that the angle θ1 between the fiber bundle PF impregnated with the resin P and the axis C of the high-pressure tank 1 is approximately a right angle as shown in Fig. 6B. On the other hand, helical winding is a winding method used mainly to increase the strength of the side end part 22 of the liner 20. The fiber bundle PF impregnated with the resin P is wound around the liner 20 prepared as shown in Fig. 6A so that it reciprocates around the side end parts 22 on both sides of the high-pressure tank 1 as shown in Fig. 6C. The angle θ2 between the fiber bundle PF and the axis C of the high-pressure tank 1 is different from hoop winding and is generally about 50° or less. In addition, the angle θ1 of the hoop winding is generally nearly 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. In general, the hoop winding and the helical winding are performed after the helical winding, but in this embodiment, the order is random, and the wire may be wound in one way and then wound in the other way, and then the winding way may be reversed.

[0039] During winding, in both the hoop winding and the helical winding, layers are stacked to form the reinforcing layer 30. The "layer" refers to the hoop layer and the helical layer, and the "addition amount of the layer" refers specifically to the mass of the 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 to be covered by each layer is covered, the winding of the layer one layer outside is performed. The determination of whether the area to be covered by each layer is 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.

[0040] As a method of supplying the solid hardener R, the hardener supply device 80 supplies the solid hardener R in such a manner that the amount of the solid hardener R added is uniform within the same layer. In addition, a predetermined amount of the solid hardener R is supplied for each layer, and in this embodiment, the amount of the solid hardener R added is gradually decreased toward the outer side of the layer, but the amount of the solid hardener R added may be changed in stages rather than gradually. In either case, the amount of the solid hardener R added to the outermost layer is the smallest compared to the inner layers, and the breaking strain is relatively small.

[0041] In this embodiment, the amount of solid hardener R added is uniform within the same layer, but as in a modified example described later, the amount of solid hardener R added may be biased 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 defined as the amount added to that layer.

[0042] According to the embodiment as 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, by applying a strain larger than the breaking strain of the surface resin layer after the reinforcing layer 30 is hardened during a pressure resistance test performed before shipping the high-pressure tank 1, it is possible to generate cracks in the surface resin layer. The generation of cracks makes it possible to prevent gas that has leaked from inside the liner and permeated the reinforcing layer from accumulating under the surface resin layer. In other words, according to this embodiment, it is possible to easily manufacture a high-pressure tank 1 that suppresses the generation of cloudiness on the surface of the tank.

[0043] <Modification of the first embodiment> Here, a modification of the first embodiment will be described.

[0044] 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 (for example, tank internal pressure of 70 MPa). In addition, as a method for setting such an amount to be added, it may be set experimentally by performing experiments multiple times.

[0045] In the first embodiment, the solid curing agent R is used as the curing agent serving as a reinforcing material, but a liquid curing agent may also be used.

[0046] However, if the hardener is liquid, it is difficult to add it evenly because it will flow off the tank surface before reacting with the resin P impregnated in the fiber bundle. On the other hand, a solid hardener is less likely to flow off the tank surface, making it easier to add it evenly.

[0047] The solid curing agent R may be added in a mixed state with the same type of resin P as the resin P impregnated in the fiber bundle PF as the curing agent. If the solid curing agent 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 curing reaction is slow and the curing time is long. In contrast, if the solid curing agent 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 curing time can be shortened. This is because the reaction activity of the surface of the solid curing agent R is increased in advance by the reaction with the mixed resin P, thereby increasing the start speed of the curing reaction with the resin P impregnated in the fiber bundle PF. In addition, compared to the case where a liquid curing agent is mixed with the resin in advance, the use of a solid curing agent has the effect of providing a longer pot life (pot life) of the mixture that has been mixed in advance.

[0048] <Second embodiment> Next, a second embodiment will be described. The second embodiment has roughly the same configuration as the first embodiment, but differs from the first embodiment mainly in the type of reinforcing material.

[0049] In this embodiment, an elastic filler R' is used as a reinforcing material. The elastic filler R' differs from the solid curing agent R used in the first embodiment in that it does not undergo a curing reaction with the resin P impregnated in the impregnation tank 60. Since it does not undergo a curing reaction, the elastic filler R' remains inside the reinforcing layer 30 as a tangible object even after curing. Since the elastic filler R' has elasticity, even when a force is applied to the reinforcing layer 30 and stress occurs, the elastic filler R' elastically deforms to relieve 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.

[0050] 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 during hardening is used as the resin P to be impregnated into the resin-impregnated fiber bundle PF, a curing agent 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 curing agent 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.

[0051] Furthermore, 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.

[0052] If the 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 after hardening of the high-pressure tank 1, making it difficult for cracks to occur. On the other hand, with this configuration, by not adding the elastic filler R' to the outermost layer, cracks are more likely to occur in the surface resin layer after hardening of the high-pressure tank 1.

[0053] <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.

[0054] 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. As long as the reinforcing material is supplied to the fiber bundle PF, the reinforcing material may be added before the roller 70.

[0055] However, if the curing agent R is added before the resin P impregnated in the fiber bundle PF is leveled by the roller 70, a problem may occur in which the resin reacts with the curing agent and starts a curing reaction, and adheres to the roller 70. As a result, the curing reaction of the resin progresses slowly on the roller 70, and the resin may become stuck on the roller 70, causing problems with the function of the roller 70.

[0056] Furthermore, if the reinforcing material is a solid, for example, a solid hardener R or an elastic filler R', the following problem may occur: the fiber bundle PF may be cut and the cut fiber bundle PF may become entangled in the roller 70, damaging the roller, etc. This is thought to be because, when the solid hardener is interposed 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, which exceeds the breaking stress of the fiber bundle PF.

[0057] By adding the reinforcing material after leveling the resin P impregnated into the fiber bundle PF with the roller 70 as in each of the above embodiments, it is possible to prevent the occurrence of these problems.

[0058] In the above embodiments, the amount of the reinforcing material R is uniform within the same layer, but this is not a required configuration. A larger amount may be added to some parts of the same layer. For example, the amount of the reinforcing material added to the part around which the side end portion 22 of the liner 20 is wound may be larger than the amount of the reinforcing material added to the part around which the body portion 21 is wound.

[0059] This configuration improves the durability of the tank when it is dropped and lands on the ground with the dome section 12 first. This is because, due to the shape characteristics 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 is dropped. It also takes into consideration that, whereas the contact area is large when the tank is dropped on the cylindrical section 11, the contact area is small when the tank is dropped on the dome section 12, and the pressure when it hits the ground is likely to be high.

[0060] 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 at the discontinuous portion when stress occurs. In contrast, according to 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 allowable range for the amount of additive to change continuously, and can be set to, for example, 10% of the amount of additive of the layer with the maximum amount of additive. [Explanation of symbols]

[0061] 1. High pressure tank 20 Liner 30 Reinforcement layer 50 Bobbin 60 Impregnation tank 70 Roller 80 Reinforcement supply device F fiber bundle P resin Fiber bundles impregnated with PF resin R Solid hardener

Claims

1. 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 the inner side of 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.

2. 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 the inner side of 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. In the step of forming the reinforcing layer, when the elastic filler is added to the fiber bundle, the amount of the elastic filler added to the fiber bundle forming the outermost layer is set to 0. A method for manufacturing the high-pressure tank according to claim 2.

4. In the step of forming the reinforcing layer, before winding the fiber bundle around the liner and before adding the reinforcing material to the fiber bundle, the fiber bundle is wound around a roller to even out the resin impregnated in the fiber bundle. A method for manufacturing a high-pressure tank according to any one of claims 1 to 3.

5. The liner has a cylindrical body and hemispherical side ends at both ends of the body, In the step of forming the reinforcing layer, when the reinforcing material is added to the fiber bundle, the amount of the reinforcing material added to the fiber bundle wound around the side end portion is made larger than the amount of the reinforcing material added to the fiber bundle wound around the body portion. A method for manufacturing a high-pressure tank according to any one of claims 1 to 4.

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