HIGH-PRESSURE TANK AND METHOD FOR MANUFACTURING A HIGH-PRESSURE TANK

Abstract

A high-pressure tank (1) has a first reinforcing layer (30) and a second reinforcing layer (34). The first reinforcing layer (30) is formed by connecting dome elements (32, 33) to respective end sections (31a) of a cylindrical element (31), the dome elements (32, 33) forming a pair and an inner circumferential surface (31b) of the cylindrical element (31) being exposed to a storage space (5) that stores gas. A first resin layer (21) covers the cylindrical element (31) between the first reinforcing layer (30) and the second reinforcing layer (34). The first resin layer (21) is less permeable to the gas in one thickness direction than the first reinforcing layer (30).

Description

BACKGROUND OF THE INVENTION

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

[0002] A high-pressure tank for storing flammable gas is used, for example, in natural gas vehicles, fuel cell vehicles, etc. This type of high-pressure tank has a reinforcing layer made of a fiber-reinforced resin and a storage chamber that holds the gas.

[0003] JP 2012-149 739 A proposes, for example, a high-pressure tank that has a first reinforcing layer made of a fiber-reinforced resin formed on the outer surface of a lining, and a second reinforcing layer made of a fiber-reinforced resin covering the first reinforcing layer. In the high-pressure tank described in JP 2012-149 739 A, the lining, which has gas barrier properties, forms a storage space that stores gas.

[0004] From US 2015 / 0 240 993 A1 and US 2009 / 0 314 785 A1, a high-pressure tank according to the preamble of claim 1 and a method for manufacturing a high-pressure tank according to the preamble of claim 2 are known. BRIEF SUMMARY OF THE INVENTION

[0005] High-pressure tanks undergo a pressure resistance test before shipping, during which the tank's storage chamber is filled with water. However, sometimes the water is not sufficiently removed from the storage chamber after the test, and some of it may remain. Additionally, water sometimes condenses due to temperature changes within the storage chamber when a high-pressure tank is in use. Due to the tank's position, this condensed water tends to collect on the inner surface of the cylindrical section (body section) of the high-pressure tank during operation.

[0006] Since the high-pressure tank described in JP 2012-149 739 A has a lining (resin layer) on the body section that reduces gas passage, this lining will come into direct contact with the water. Depending on the material of the lining (resin layer), the water may damage the lining.

[0007] Embodiments of the present invention provide a high-pressure tank which prevents a resin layer which reduces the passage of gas from being damaged by contact with water, and a method for manufacturing such a high-pressure tank.

[0008] A first embodiment of the present invention relates to a high-pressure tank having the features of claim 1.

[0009] According to this embodiment of the present invention, the resin layer covering the cylindrical element is less permeable to gas in the thickness direction (i.e., it has better gas barrier properties) than the first reinforcing layer. This configuration reduces leakage of gas passing through the cylindrical element of the first reinforcing layer to the outside through the second reinforcing layer. Furthermore, the resin layer does not form the storage space. Therefore, even if there is water in the storage space, this water will not come into direct contact with the resin layer. This configuration reduces damage to the resin layer from contact with water.

[0010] The dome elements are fitted onto the cylinder element from one of its outer sides. In each fitting section where the dome elements are fitted onto the cylinder element, a portion of the resin layer is located between the cylinder element and the dome element.

[0011] The gas in the storage chamber likely leaks through the fitting sections where the dome elements are fitted onto the cylinder element. However, according to this design, a portion of the resin layer is formed in the fitting sections between the cylinder element and the dome element. This configuration thus reduces gas leakage between the cylinder element and the dome elements.

[0012] A second embodiment of the present invention relates to a method for manufacturing a high-pressure tank according to claim 2.

[0013] According to the above embodiment of the present invention, the resin layer covering the cylindrical element is less permeable to gas in the thickness direction than the first reinforcing layer. It is therefore possible to produce a high-pressure tank that reduces gas leakage through the second reinforcing layer from the cylindrical element of the first reinforcing layer to the outside. Accordingly, it is not necessary to form a lining with good gas barrier properties on the inner circumferential surface of the cylindrical element. Furthermore, the resin layer does not form the storage space. Even if there is water in the storage space, this water will not come into direct contact with the resin layer. Since this configuration reduces damage to the resin layer from contact with water, resins, etc., that are easily damaged by water can also be used for the resin layer.This increases the number of choices for the resin layer material.

[0014] When manufacturing the connected element, in each fitting section where the dome elements are fitted onto the cylinder element, a portion of the resin layer is formed between the cylinder element and the dome element, the fitting sections being formed by fitting the dome elements from an outside of the cylinder element onto the cylinder element whose outer circumferential surface is covered with the resin layer.

[0015] This method allows for the creation of a high-pressure tank in which a portion of the resin layer forms between the cylinder element and each coupling element. This high-pressure tank thus reduces gas leakage between the cylinder element and each coupling element.

[0016] The high-pressure tank and the method for manufacturing a high-pressure tank according to the above embodiments of the present invention prevent the resin layer, which reduces the passage of the gas, from being damaged by contact with water. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] With reference to the accompanying drawings, in which the same reference numerals denote the same elements, the features, advantages, and technical and industrial significance of exemplary embodiments of the invention are described below. The drawings show: Fig. 1 a schematic sectional view showing the construction of a high-pressure tank according to an embodiment of the invention; Fig. 2 a partial sectional view showing the structure of the in Fig. The high-pressure tank shown in section 1 is shown; Fig. 3. A flowchart showing the steps of a process for producing the in Fig. 1 shows the high-pressure tanks; Fig. 4 a sectional view showing a method for forming a cylindrical element in a Fig. The element formation step shown in section 3 represents; Fig. 5 a partial sectional view showing a method for forming a pair of dome elements in the Fig. The element formation step shown in section 3 represents; Fig. 6 a sectional view of the dome elements, which are in the Fig. 3 element training steps shown were trained; Fig. 7 a sectional view of the dome elements of Fig. 6 with a second resin layer, which is in the Fig. 3 element training steps shown were performed on them; Fig. 8 a sectional view showing one in Fig. 3 shows the training step for the first resin layer; Fig. 9 a schematic perspective view that shows one in Fig. 3 represents the training step for the first reinforcement layer; Fig. 10 a sectional view of a connected element that is in the Fig. 3 training step shown for the first reinforcement layer was trained; Fig. 11 a sectional view showing the structure of a variation of the in Fig. The high-pressure tank shown in section 1 is shown; Fig. 12 a partial sectional view showing the structure of the in Fig. The 11 high-pressure tanks shown are shown; Fig. 13 a flowchart showing the steps of a process for producing the in Fig. 11 high-pressure tanks shown; Fig. 14 a schematic perspective view, which gives one in Fig. 13 shows the training step for the first reinforcement layer; and Fig. 15 a sectional view of a connected element that is in the Fig. The training step shown in section 13 was for the first reinforcement shift. DETAILED DESCRIPTION OF THE EXAMPLES OF EXECUTION

[0018] The following will refer to the Fig. Sections 1 to 15 describe an embodiment of the invention and a modification thereof. 1. High-pressure tank 1

[0019] Here, a high-pressure tank 1 is described as a tank installed in a fuel cell vehicle and filled with high-pressure hydrogen gas. However, the high-pressure tank 1 can also be used for other purposes. The gas used in the high-pressure tank 1 is not limited to high-pressure hydrogen gas. Examples of gases that can be used in the high-pressure tank 1 include various compressed gases such as compressed natural gas (CNG), various liquefied gases such as liquefied natural gas (LNG) and LPG, as well as other gases.

[0020] As in Fig. As shown in Figure 1, the high-pressure tank 1 is a generally cylindrical high-pressure gas storage container with domed, rounded ends. The high-pressure tank 1 has a gas barrier section 2 with gas barrier properties and a reinforcement section 3 made of a fiber-reinforced resin. The gas barrier section 2 has a first resin layer 21 and second resin layers 22, 23. The reinforcement section 3 has a first reinforcement layer 30 and a second reinforcement layer 34. The high-pressure tank 1 has an opening at one end, and a nozzle 4 is fitted around the opening. The high-pressure tank 1 also has a storage chamber 5 that stores gas. For use, the high-pressure tank 1 is mounted horizontally such that the axis (a cylindrical element 31, described below) of the high-pressure tank 1 extends in the horizontal direction.

[0021] The nozzle 4 is formed by machining a metallic material such as aluminum or an aluminum alloy into a predetermined shape. A valve 6 is attached to the nozzle 4, which controls the flow of hydrogen gas into and out of the storage chamber 5. The valve 6 is provided with a sealing element 6a. The sealing element 6a is in contact with the gas barrier section 2 in a projecting section 32b of a coupling element 32, which will be described later, and seals the storage chamber 5 of the high-pressure tank 1.

[0022] The gas barrier section 2 is a layer that reduces leakage of the gas stored in the storage chamber 5 to the outside. As described above, the gas barrier section 2 has the first resin layer 21 and the second resin layers 22, 23. The first resin layer 21 of this embodiment can be considered the “resin layer” according to the invention. The first resin layer 21 and the second resin layers 22, 23 are described later.

[0023] The reinforcing section 3 improves the mechanical strength of the high-pressure tank 1, specifically its stiffness and compressive strength, and is made of a fiber-reinforced resin consisting of resin-impregnated reinforcing fibers (continuous fibers). The reinforcing section 3 comprises a first reinforcing layer 30 and a second reinforcing layer 34, which covers the outer surface of the first reinforcing layer 30. The first reinforcing layer 30 has a cylindrical element 31 and a pair of dome elements 32, 33. The dome elements 32, 33 are connected to respective end sections 31a of the cylindrical element 31. The first reinforcing layer 30 is formed as a single piece by connecting the cylindrical element 31 and the dome elements 32, 33.

[0024] The first reinforcing layer 30 consists of a multitude of fiber-reinforced resin layers, which in turn consist of (matrix-)resin-impregnated reinforcing fibers. The reinforcing fibers of the cylindrical element 31 are oriented along the circumference of the cylindrical element 31 at an angle that is substantially perpendicular to the X-axis of the cylindrical element 31. In other words, the reinforcing fibers in the cylindrical element 31 are oriented in the circumferential direction of the cylindrical element 31. The reinforcing fibers of the dome elements 32, 33 are not oriented in the circumferential direction of the cylindrical element 31, but extend in various directions that intersect the circumferential direction, from near the head ends of the dome elements 32, 33 to circumferential end sections 32a, 33a of the dome elements 32, 33.

[0025] In this embodiment, the reinforcing fibers of the cylinder element 31 and the reinforcing fibers of the dome elements 32, 33 are not continuous (not connected). As will be described later, this is because the cylinder element 31 and the dome elements 32, 33 are formed separately, and the dome elements 32, 33 are then attached to the respective ends of the cylinder element 31.

[0026] Examples of reinforcing fibers for the first reinforcing layer 30 (i.e., the cylindrical element 31 and the dome elements 32, 33) include glass fibers, aramid fibers, boron fibers, and carbon fibers. Carbon fibers are particularly preferable with regard to lightness, mechanical strength, etc.

[0027] The matrix resin with which the reinforcing fibers for the first reinforcing layer 30 are impregnated is, without being particularly limited, a thermoplastic resin or a reactive resin. Examples of thermoplastic resins include polyetheretherketone, polyphenylene sulfide, polyacrylates, polyimide, polyamide, nylon 6, and nylon 6.6. Examples of reactive resins include a phenolic resin, a melamine resin, a urea resin, and an epoxy resin. An epoxy resin is particularly preferable in view of mechanical strength, etc. Epoxy resins are liquid when uncured and, when thermally cured, form a strong, cross-linked structure.

[0028] The second reinforcing layer 34 consists of a plurality of fiber-reinforced resin layers made of (matrix) resin-impregnated reinforcing fibers. In this embodiment, the second reinforcing layer 34 covers the first resin layer 21, which is formed on the surface of the cylindrical element 31, and the outer surfaces of the dome elements 32, 33.

[0029] Specifically, the second reinforcing layer 34 is a layer of fiber-reinforced resin, with the reinforcing fibers oriented over the dome elements 32, 33. The reinforcing fibers of the second reinforcing layer 34 are oriented by helically winding a resin-impregnated fiber bundle such that they are inclined with respect to the X-axis of the cylinder element 31. The dome elements 32, 33 can be held to the cylinder element 31 by the reinforcing fibers. This prevents the dome elements 32, 33 from detaching outwards from the cylinder element 31 due to gas pressure in the X-axis direction when the high-pressure tank 1 is in use.

[0030] Examples of the reinforcing fibers of the second reinforcing layer 34 include similar materials to those mentioned above as examples of the reinforcing fibers of the first reinforcing layer 30, while examples of the matrix resin with which the reinforcing fibers for the second reinforcing layer 34 are impregnated include similar materials to those mentioned above as examples of the matrix resin of the first reinforcing layer 30.

[0031] In this embodiment, the first resin layer 21 of the gas barrier section 2 is formed between the first reinforcing layer 30 and the second reinforcing layer 34, so that it covers the cylindrical element 31. The first resin layer 21 is, for example, thinner than the first reinforcing layer 30. The thickness of the first resin layer 21 can be from 0.05 mm to 5 mm, while the thickness of the first reinforcing layer 30 can be 10 mm or more. The first resin layer 21 has a lower gas permeability (i.e., better gas barrier properties) in the thickness direction than the first reinforcing layer 30.

[0032] This reduces the leakage of gas passing through the first reinforcing layer 30 to the outside through the second reinforcing layer 34. In particular, the amount of gas permeation increases with the increasing surface area of ​​the high-pressure tank 1. Since, in this embodiment, the surface area of ​​the cylinder element 31 is larger than the total surface area of ​​the coupling elements 32, 33, a greater quantity of gas passes through the cylinder element 31 than through the coupling elements 32, 33. Accordingly, the first resin layer 21 is formed on the cylinder element 31. This effectively reduces the leakage of gas passing through the first reinforcing layer 30 to the outside through the second reinforcing layer 34.

[0033] The statement "the first resin layer 21 has a lower gas permeability in the thickness direction than the first reinforcing layer 30" means that the first resin layer 21 is less permeable to gas (has better gas barrier properties) in the radial direction of the cylindrical element 31 than the first reinforcing layer 30. The relationship between the gas permeability of the first resin layer 21 and the first reinforcing layer 30 can be verified by producing specimens of the same thickness as the first resin layer 21 and specimens of the same thickness as the first reinforcing layer 30 and measuring the amount of gas (stored gas) that passed through the specimens. For example, a resin with a lower gas permeability than the matrix resin with which the reinforcing fibers for the first reinforcing layer 30 are impregnated can be used for the first resin layer 21.

[0034] It is preferable for the first resin layer 21 to have adhesion to the first reinforcement layer 30 and the second reinforcement layer 34. This can prevent separation between the first resin layer 30 and the second resin layer 34 when the high-pressure tank 1 is in use, and thus the fatigue strength of the high-pressure tank 1 can be maintained.

[0035] For example, it is preferable that the resin of the first resin layer 21 and the fiber-reinforced resin of the first reinforcement layer 30 are chemically bonded by a chemical reaction, such as a cross-linking reaction or polymerization reaction.

[0036] The material for the first resin layer 21 can be a resin material that contains a synthetic resin with gas barrier properties and an elastomer as its base material. The synthetic resin with gas barrier properties is not particularly restricted, as long as it has better gas barrier properties than the matrix resin. The synthetic resin with gas barrier properties can, for example, be a thermoplastic resin. Examples of thermoplastic resins include polyester resins and polyvinyl alcohol resins. Considering good gas barrier properties, polyethylene naphthalate (PEN) is preferable as a polyester resin and ethylene-vinyl alcohol copolymer (EVOH) as a polyvinyl alcohol resin.

[0037] The elastomer is not particularly limited as long as it improves adhesion. The elastomer can be, for example, rubber or modified rubber—specifically, rubber modified to have functional groups on its surface. Examples of rubber include ethylene-butene copolymer (EBR), styrene-butadiene rubber (SBR), and nitrile rubber (NBR).

[0038] The functional groups of the modified rubber are not particularly restricted, as long as they are functional groups that improve the adhesion to the first reinforcing layer 30 and the second reinforcing layer 34. If, for example, the matrix resin for the first reinforcing layer 30 and the second reinforcing layer 34 is an epoxy resin, the functional groups of the modified rubber can be, for example, any functional groups that react with epoxy groups, such as carboxyl groups, hydroxyl groups, or amino groups.

[0039] Examples of such resin materials include a resin material containing PEN and modified rubber with carboxyl or amino groups, and a resin material containing EVOH and modified rubber with carboxyl or amino groups.

[0040] Alternatively, a sheet or film material with a three-layer structure can be used as the material for the first resin layer 21. Specifically, the material for the first resin layer 21 can be a sheet or film material composed of a barrier layer with gas barrier properties and adhesion promoter layers that have adhesive properties and are formed on both surfaces of the barrier layer. A resin for the barrier layer can be a similar resin to the synthetic resin with gas barrier properties described above. Examples of barrier layer resins include EVOH and PEN. A resin for the adhesion promoter layers can be, for example, a thermoplastic resin such as polypropylene resin (PP) or polyamide resin (PA).

[0041] Examples of such sheet or film materials include those composed of a barrier layer made of EVOH and adhesion promoter layers made of PP, formed on both surfaces of the barrier layer. Further examples include those composed of a barrier layer made of EVOH and adhesion promoter layers made of PA, formed on both surfaces of the barrier layer.

[0042] Alternatively, an adhesion promoter material consisting of a urethane resin and a filler, such as an inorganic material, can be used as the material for the first resin layer 21. The use of a urethane resin results in the first resin layer 21 exhibiting high elongation at low temperatures. The addition of the filler improves the gas barrier properties of the first resin layer 21. Another adhesion promoter material that can be used as the material for the first resin layer 21 is a modified epoxy resin, as it has good gas barrier properties and high elongation at low temperatures.

[0043] As in Fig. As shown in Figure 1, in this embodiment the second resin layers 22, 23 are designed such that they form inner surfaces 32f, 33f (see Figure 1). Fig. 6) of the dome elements 32, 33, specifically the surfaces of the dome elements 32, 33, which are each located on the inside of the high-pressure tanks 1. However, the second resin layers 22, 23 do not necessarily have to cover the Fig. The second resin layers 22, 23 can be formed between the first reinforcement layer 30 and the second reinforcement layer 34 such that they each cover the dome elements 32, 33.

[0044] The material for the second resin layers 22, 23 can be the resin material, the sheet or film material, or the adhesion promoter material mentioned above as an example of the material for the first resin layer 21. The material for the first resin layer 21 and the material for the second resin layers 22, 23 can be either the same or different.

[0045] How Fig. As shown in Figure 1, in this embodiment of the high-pressure tank 1, an inner circumferential surface 31b of the cylindrical element 31 is exposed towards the storage space 5, the storage space 5 being formed by the inner circumferential surface 31b of the cylindrical element 31 and the second resin layers 22, 23. The first resin layer 21 does not form the storage space 5. Therefore, even if water collects on the inner circumferential surface 31b of the cylindrical element 31 of the so-called horizontal high-pressure tank 1, this water will not come into direct contact with the first resin layer 21. This configuration reduces damage to the first resin layer 21 due to contact with water.

[0046] For example, resins with good gas barrier properties, such as PEN and EVOH, have polar groups in their molecules. Because of these polar groups, these resins are easily hydrolyzed by water or swell and can therefore have reduced gas barrier properties. In this embodiment, however, the first resin layer 21 does not come into direct contact with water, as described above. Therefore, the first resin layer 21 has good gas barrier properties.

[0047] As in the Fig. 1 and Fig. As shown in Figure 2, in the high-pressure tank 1 of this embodiment, the coupling elements 32, 33 are fitted onto the cylinder element 31 from the outside. Specifically, the circumferential end sections 32a, 33a of the coupling elements 32, 33 are fitted onto the end sections 31a of the cylinder element 31 from the outside of the cylinder element 31. An outer circumferential surface 31c (see Figure 2) Fig. 4) of the cylindrical element 31 is covered with the first resin layer 21.

[0048] In each pass section 30a, where the dome elements 32, 33 are fitted onto the cylinder element 31, a portion of the first resin layer 21 is formed between the cylinder element 31 and each dome element 32, 33. Although the gas stored in the storage chamber 5 tends to leak through the pass sections 30a, where the dome elements 32, 33 are fitted onto the cylinder element 31, this configuration reduces leakage between the cylinder element 31 and each dome element 32, 33.

[0049] In this embodiment, the inner surfaces 32f, 33f of the dome elements 32, 33 are each covered with the second resin layers 22, 23. In each of the fitting sections 30a, a portion of the first resin layer 21 and a portion of the second resin layers 22, 23 are formed between the cylinder element 31 and each dome element 32, 33, with the portion of the first resin layer 21 and the portion of the second resin layers 22, 23 lying on top of each other (being connected to each other). This configuration effectively reduces gas leakage between the cylinder element 31 and each dome element 32, 33. 2. Manufacturing process for high-pressure tank 1

[0050] Next, a method for manufacturing the high-pressure tank 1 according to the embodiment according to the invention will be described. Fig. Figure 3 is a flowchart illustrating the steps of the process for manufacturing high-pressure tank 1. As shown in Fig. As shown in Figure 3, the method for manufacturing the high-pressure tank 1 includes an element formation step S11, a formation step for the first resin layer S12, a formation step for the first reinforcement layer S13, and a formation step for the second reinforcement layer S14. The element formation step S11, the formation step for the first resin layer S12, and the formation step for the first reinforcement layer S13 can be considered, in the invention, as "making a connected element". 2-1. Element training step S11

[0051] As in Fig. As shown in Figure 3, the element formation step S11 is first carried out in the process for manufacturing the high-pressure tank 1. In this step, the cylinder element 31 is formed and the dome elements 32, 33 covered with the second resin layers 22, 23 are formed. This step can be omitted, whereby the cylinder element 31 and the dome elements 32, 33 covered with the second resin layers 22, 23 can be manufactured separately. Method for forming the cylindrical element 31

[0052] As in Fig. As shown in Figure 4, the cylindrical element 31 is formed in a method for forming the cylindrical element 31 by, for example, winding a fiber sheet F1 around a cylindrical mandrel 100. The outer diameter D1 of the mandrel 100 is an outer diameter that corresponds to the inner diameter of the cylindrical element 31, and it is preferably set to such a value that the coupling elements 32, 33 can be fitted onto the cylindrical element 31 from the outside.

[0053] When the cylindrical element 31 is formed, the fiber sheet F1 that is dispensed is wound several times around the mandrel 100 while the mandrel 100 is rotated circumferentially by a rotary mechanism (not shown). The fiber sheet F1 is a sheet consisting of reinforcing fibers oriented in one direction and impregnated with a matrix resin. The fiber sheet F1 is wound around the mandrel 100 such that the reinforcing fibers are oriented circumferentially. In this way, the cylindrical element 31 is formed in which the reinforcing fibers are oriented circumferentially.

[0054] Similar materials can be used as reinforcing fibers for the fiber sheet F1 as those mentioned above as examples of the reinforcing fibers of the first reinforcing layer 30, while similar materials can be used as matrix resin with which the reinforcing fibers for the fiber sheet F1 are impregnated, as mentioned above as examples of the matrix resin of the first reinforcing layer 30.

[0055] As in Fig. As shown in Figure 4, the end sections 31a of the cylindrical element 31 gradually become thinner towards the ends of the cylindrical element 31 in the axial direction X. With such a shape, it is less likely that steps will form at the connecting sections between the outer surface of the cylindrical element 31 and the outer surfaces of the dome elements 32, 33 when the circumferential end sections 32a, 33a of the dome elements 32, 33 are placed on the end sections 31a of the cylindrical element 31.

[0056] To gradually thin the end sections 31a of the cylindrical element 31 in the axial direction X towards the ends of the cylindrical element 31 in the axial direction X, the winding width of the fiber sheet F1 can be gradually reduced. Alternatively, the end sections 31a of the cylindrical element 31 in the axial direction X can be gradually thinned towards the ends of the cylindrical element 31 in the axial direction X by pressing the two end sections 31a through a roller, etc.

[0057] In the example described above, the cylindrical element 31 is formed by winding the fiber sheet F1 around the mandrel 100. However, the cylindrical element 31 can also be formed by filament winding (FW process) of a matrix resin-impregnated fiber bundle around the mandrel 100. Alternatively, the cylindrical element 31 can be formed by so-called centrifugal winding (CW process), namely by attaching a fiber sheet to the inner surface of the rotating mandrel 100.

[0058] If the matrix resin is a reactive resin, the fiber sheet F1 wound around the mandrel 100 is heated to cure the uncured reactive resin. If, on the other hand, the matrix resin is a thermoplastic resin, the thermoplastic resin is cooled in its softened state to allow the resin in the fiber sheet F1 to solidify. After the resin has cured or solidified, the cylindrical element 31 is removed from the mandrel 100. If a reactive resin is used, the matrix resin can be cured and allowed to react (crosslink or polymerize) with the resin of the first resin layer 21 after the first resin layer formation step S12, which is described later. This increases the adhesion between the cylindrical element 31 and the first resin layer 21. Method for forming the dome elements 32, 33 with second resin layers

[0059] In a process for forming the dome elements 32, 33 covered with the second resin layers 22, 23, the in Fig. 6 dome elements 32, 33 shown. As in Fig. As shown in Figure 5, in this process a fiber bundle F2 impregnated with a matrix resin is wound around a mandrel 200 by filament winding (FW process). Specifically, the mandrel 200 has a body section 201 and a shaft section 202, which extends outwards from one end of the body section 201.

[0060] Body section 201 has a circular shape when viewed along the axis of shaft section 202. Body section 201 has a groove 201a in its center along its axis. The groove 201a is formed in the outer circumferential surface of body section 201 and extends along its entire circumference. The mandrel 200 has a shape corresponding to the interconnected dome elements 32 and 33. The mandrel 200 has the groove 201a at a location corresponding to the connection between the dome elements 32 and 33. Shaft section 202 is rotatably supported by a rotary mechanism (not shown).

[0061] When the dome elements 32, 33 are formed, the mandrel 200 is first rotated to wind the fiber bundle F2 such that the fiber bundle F2 covers the outer surface of the mandrel 200, thereby forming a winding body 35. The fiber bundle F2 is also wound around the shaft section 202, in order to, as Fig. Figure 6 shows how to form the cylindrical projecting section 32b with a through-hole 32c. The fiber bundle F2 is wound at an angle of, for example, 30 to 50 degrees with respect to the axial direction of the shaft section 202.

[0062] The reinforcing fibers for fiber bundle F2 can be made of materials similar to those mentioned above as examples for the reinforcing fibers of the first reinforcing layer 30. Similarly, the matrix resin used to impregnate the reinforcing fibers for fiber bundle F2 can also be made of materials similar to those mentioned above as examples for the matrix resin of the first reinforcing layer 30. If the matrix resin for fiber bundle F2 is a thermoplastic resin, the fiber bundle F2 is wound around the mandrel 200 while the thermoplastic resin is softened by heating. Conversely, if the matrix resin for fiber bundle F2 is a reactive resin, the fiber bundle F2 is wound around the mandrel 200 while the reactive resin is uncured.

[0063] The winding body 35 can be pressed by a roller etc. near the point on the winding body 35 that corresponds to the connection between the coupling elements 32, 33, such that the circumferential end sections 32a, 33a of the coupling elements 32, 33 of the cylindrical element 31 gradually become thinner in the axial direction X towards the ends.

[0064] Next, the winding body 35, which was formed on the outer surface of the mandrel 200, is divided into two parts by means of a cutter 210 (see Fig. 5). As in Fig. As shown in Figure 6, the two parts of the winding body 35 are then removed from the mandrel 200. In this way, the dome elements 32, 33 are formed.

[0065] In the Fig. In the state shown in Figure 5, the nozzle 4 is attached to the outer surface of the preceding section 32b. If the resin with which the fiber bundle F2 of the winding body 35 is impregnated is a reactive resin, the winding body 35 is cured. If the resin with which the fiber bundle F2 of the winding body 35 is impregnated is a thermoplastic resin, the thermoplastic resin is cooled in its softened state to allow the resin in the fiber bundle F2 to solidify.

[0066] Once the resin with which the fiber bundle F2 is impregnated has hardened or solidified as described above, a blade of the cutter 210 is inserted into the groove 201a of the mandrel 200 while the mandrel 200 is rotated.

[0067] The fiber bundle F2 is cut by the cutter 210 in this way. The winding body can thus be divided into two parts. The two parts obtained in this way are then removed by the mandrel 200. In this way, the dome elements 32, 33 are formed.

[0068] As in the Fig. 6 and Fig. As shown in Figure 7, the second resin layers 22, 23 are next formed on the inner surfaces 32f, 33f of the dome elements 32, 33. Specifically, if the resin material or adhesion promoter material mentioned as an example of the material for the first resin layer 21 is used, the second resin layers 22, 23 can be formed by liquefying or softening the resin material or adhesion promoter material, applying the liquefied or softened resin material or adhesion promoter material to the inner surfaces 32f, 33f, and allowing the applied resin material or adhesion promoter material to cure or solidify. Alternatively, if the sheet or film material, etc., mentioned as an example of the material for the first resin layer 21 is used, the second resin layers 22, 23 can be formed by bonding the sheet or film material to the inner surfaces 32f, 33f.

[0069] In this embodiment, the formation of the dome elements 32, 33 and the coating of the dome elements 32, 33 with the second resin layers 22, 23 are carried out separately. However, the formation of the dome elements 32, 33 and the coating of the dome elements 32, 33 with the second resin layers 22, 23 can be carried out simultaneously. In this case, the surface of the Fig. For example, resin layers are formed on the mandrel 200 shown in Figure 5, which serve as the second resin layers 22, 23, whereby the winding body 35 can then be formed on these resin layers. Afterwards, the winding body 35 can be cut into two parts. In this way, the dome elements 32, 33 can be formed with the second resin layers 22, 23.

[0070] In the example described above, the second resin layers 22, 23 are formed on the inner surfaces 32f, 33f of the dome elements 32, 33. However, the invention is not limited to this, and the second resin layers 22, 23 can be formed on outer surfaces 32g, 33g (see Figure 1). Fig. 6) of the dome elements 32, 33 are formed on the surfaces of the dome elements 32, 33, which are each located on the outside of the high-pressure tank 1. In this case, the inner surfaces 32f, 33f of the dome elements 32, 33 can be exposed towards the storage space 5. 2-2. Training step for first resin layer S12

[0071] As in Fig. As shown in section 3, the next step is the training step for the first resin layer S12. As shown in the Fig. 4 and Fig. As shown in Figure 8, the first resin layer 21 is formed in this step such that it covers the outer circumferential surface 31c of the fabricated cylindrical element 31. The first resin layer 21 has a lower gas permeability in the thickness direction than the first reinforcing layer 30. It is preferable that the first resin layer 21 has adhesion to the first reinforcing layer 30 and the second reinforcing layer 34.

[0072] If, as described above, a resin material is used as the material for the first resin layer 21 which contains as a base material a synthetic resin with gas barrier properties and an elastomer that improves adhesion, the resin material can be liquefied or softened and applied to the outer circumferential surface 31c of the cylindrical element 31 to form the first resin layer 21.

[0073] If the first resin layer 21 (or the synthetic resin as base material) is a thermoplastic resin and the matrix resin of the second reinforcement layer 34 is a reactive resin, it is preferable that the glass transition temperature (Tg) of the resin of the first resin layer 21 is lower than the curing temperature of the matrix resin of the second reinforcement layer 34.

[0074] When the matrix resin of the second reinforcing layer 34, which will be described later, is cured by heating, the thermoplastic resin of the first resin layer 21 is softened (melted). Therefore, the first resin layer 21 adheres to the second reinforcing layer 34. The first resin layer 21 and the matrix resin of the second reinforcing layer 34 can be chemically bonded by a chemical reaction such as a crosslinking or polymerization reaction. This improves the adhesion between the first reinforcing layer 30 and the second reinforcing layer 34 via the first resin layer 21. The glass transition temperature Tg of a thermoplastic resin can be adjusted to a desired value by modifying the average molecular weight of the monomers, the degree of polymerization of the resin from monomers to polymers, and similar parameters.

[0075] If the matrix resin of the second reinforcement layer 34 is an epoxy resin, it is preferable that the elastomer contained in the resin material described above be modified rubber, specifically rubber modified to have functional groups on its surface that react with the epoxy groups of the epoxy resin. These functional groups can be, for example, carboxyl groups, hydroxyl groups, or amino groups. Accordingly, when the matrix resin of the second reinforcement layer 34 is cured by heating, the epoxy resin of the second reinforcement layer 34 and the functional groups of the modified rubber are chemically bonded. This improves the adhesion between the first reinforcement layer 30 and the second reinforcement layer 34.

[0076] As described above, a sheet or film material can be used as the material for the first resin layer 21. This material consists of a barrier layer with gas barrier properties and adhesion promoter layers that have adhesive properties and are formed on both surfaces of the barrier layer. When the first resin layer 21 is formed, the sheet or film material can, in this case, be wrapped at least once around the cylindrical element 31 and applied to the outer circumferential surface 31c of the cylindrical element 31.

[0077] If the adhesion promoter layer is a thermoplastic resin and the matrix resin of the second reinforcement layer 34 is a reactive resin, it is preferable that the thermoplastic resin be chemically bonded to the matrix resin under such a temperature condition that the matrix resin of the second reinforcement layer 34 is cured.

[0078] If the aforementioned adhesion promoter material is used as the material for the first resin layer 21, the adhesion promoter material can be applied to the outer circumferential surface 31c. If the resin material or adhesion promoter material contained in the material of the first resin layer 21 is a reactive resin, the resin can be cured by heating. If a reactive resin is used, the reactive resin of the first resin layer 21 can be cured together with the matrix resin of the second reinforcement layer 34 in the training step for the second reinforcement layer S14. This can improve the adhesion between the first resin layer 21 and the second resin layer 34.

[0079] In this embodiment, the first resin layer 21 is formed while the cylindrical element 31 remains on the mandrel 100. However, the first resin layer 21 can also be formed, for example, after the cylindrical element 31 has been removed from the mandrel 100. 2-3rd training step for first reinforcement layer S13

[0080] As in Fig. As shown in section 3, the training step for the first reinforcement layer S13 is then carried out. As shown in the Fig. 9 and Fig. As shown in Figure 10, in this step the dome elements 32, 33 are connected to the end sections 31a of the cylindrical element 31. Specifically, the circumferential end sections 32a, 33a of the dome elements 32, 33 are connected to the end sections 31a of the cylindrical element 31. In this way, a connected element 30A can be formed, which serves as the first reinforcing layer 30.

[0081] In this embodiment, the cylindrical element 31 has formed the first resin layer 21 on its outer circumferential surface 31c, while the dome elements 32, 33 have formed the second resin layers 22, 23 on their inner surfaces 32f, 33f. By connecting such a cylindrical element 31 and such dome elements 32, 33, it is possible, as shown in Fig. As shown in Figure 10, the connected element 30A is formed, which has the first reinforcement layer 30 and the gas barrier section 2.

[0082] When the cylindrical element 31 and the dome elements 32, 33 are joined, the dome elements 32, 33 are fitted onto the cylindrical element 31 from the outside, with its outer circumferential surface 31c being covered with the first resin layer 21. In each of the fitting sections 30a (see Fig. 2) in which the coupling elements 32, 33 are fitted onto the cylinder element 31, a portion of the first resin layer 21 is formed between the cylinder element 31 and each coupling element 32, 33. This allows the high-pressure storage tank 1 to be created, in which a portion of the first resin layer 21 is formed between the cylinder element 31 and each coupling element 32, 33. The high-pressure tank 1 reduces gas leakage between the cylinder element 31 and each coupling element 32, 33.

[0083] In this embodiment, in each of the fitting sections 30a between the cylindrical element 31 and each dome element 32, 33, a portion of the first resin layer 21 and a portion of the second resin layers 22, 23 are formed. When the cylindrical element 31 and the dome elements 32, 33 are joined, the portion of the first resin layer 21 and the portion of the second resin layers 22, 23 are therefore joined together in such a way that they lie on top of each other.

[0084] The cylindrical element 31 and the dome elements 32, 33 can be connected via the first and second resin layers 21 to 23 formed in the fitting sections 30a. If the resins forming the first and second resin layers 21 to 23 are thermoplastic resins, the fitting sections 30a can be heat-sealed (connected) by heating the fitting sections 30a and melting the thermoplastic resins. If, on the other hand, the resins forming the first and second resin layers 21 to 23 are reactive resins, the fitting sections 30a can be connected by curing them through heating.

[0085] If the matrix resins forming the cylinder element 31 and the dome elements 32, 33 are thermoplastic resins, alternatively the end sections 31a of the cylinder element 31 and the circumferential end sections 32a, 33a of the dome elements 32, 33 can be heat-sealed (joined) by heating the end sections 31a of the cylinder element 31 and the circumferential end sections 32a, 33a of the dome elements 32, 33 to melt the thermoplastic resins while the circumferential end sections 32a, 33a of the dome elements 32, 33 are fitted onto the end sections 31a of the cylinder element 31. If, on the other hand, the matrix resins forming the cylinder element 31 and the dome elements 32, 33 are reaction resins, the cylinder element 31 and the dome elements 32, 33 can be joined by fitting the dome elements 32, 33 onto the cylinder element 31 and curing the reaction resins by heating.

[0086] How Fig. As shown in Figure 10, in the connected element 30A, which was manufactured in this way, the inner circumferential surface 31b of the cylindrical element 31 is exposed towards the storage space 5, and the storage space 5 is formed by the inner circumferential surface 31b of the cylindrical element 31 and the second resin layers 22, 23. This means that the first resin layer 21 does not form the storage space 5.

[0087] In the connected element 30A, the outer circumferential surface 31c of the cylindrical element 31 is covered with the first resin layer 21. When the second reinforcing layer 34 is formed, which will be described later, the first resin layer 21 can accordingly be formed between the first reinforcing layer 30 and the second reinforcing layer 34, so that it covers the cylindrical element 31. As described above, such a first resin layer 21 has a lower gas permeability in the thickness direction than the first reinforcing layer 30. 2-4. Training step for second reinforcement layer S14

[0088] As in Fig. As shown in section 3, the training step for the second reinforcement layer S14 is then carried out. As shown in the Fig. 10 and Fig. As shown in Figure 1, in this step the second reinforcement layer 34 is formed by winding a fiber bundle impregnated with a resin (matrix resin) spirally around the dome elements 32, 33 around the manufactured connected element 30A.

[0089] Specifically, the fiber bundle impregnated with the matrix resin, which becomes the second reinforcing layer 34, is wound spirally in layers around the surface of the connected element 30A by a fiber winding process. As described above, in this embodiment, the outer circumferential surface 31c of the cylindrical element 31 in the connected element 30A is covered with the first resin layer 21. Accordingly, the fiber bundle is wound around the surface of the first resin layer 21 and the outer surfaces 32g, 33g of the dome elements 32, 33.

[0090] Spiral winding is a winding process in which the fiber bundle is wound obliquely (in the range of 10° or more and 60° or less) over the dome elements 32, 33 with respect to the axial direction X of the cylindrical element 31. The number of layers of the wound fiber bundle is, for example, approximately 2 to 10. However, the number of layers of the wound fiber bundle is not particularly limited as long as the second reinforcing layer 34 is sufficiently strong.

[0091] Similar materials to those mentioned above as examples of the reinforcing fibers of the first reinforcing layer 30 can be used as reinforcing fibers for the fiber bundle, while similar materials to those mentioned above as examples of the matrix resin of the first reinforcing layer 30 can be used as matrix resin with which the reinforcing fibers for the fiber bundles are impregnated.

[0092] If the matrix resin with which the fiber bundle is impregnated is a reactive resin, this resin will cure after the fiber bundle has been wrapped around the connected element 30A. If the matrix resin of the first reinforcement layer 30 and the resins of the first and second resin layers 21 to 23 are reactive resins and have not fully cured, these resins will also cure at this time. If the matrix resin with which the fiber bundle is impregnated is a thermoplastic resin, this resin will be allowed to cool or be forced cooled and allowed to solidify. If the matrix resin of the first reinforcement layer 30 and the resins of the first and second resin layers 21 to 23 are thermoplastic resins and have not fully solidified, these resins will also be cooled and allowed to solidify.

[0093] By forming the second reinforcing layer 34 in this way, the reinforcing section 3 can be formed with the first reinforcing layer 30 and the second reinforcing layer 34. In the reinforcing section 3, the first resin layer 21 is formed between the first reinforcing layer 30 and the second reinforcing layer 34 such that it covers the cylindrical element 31. Since the adhesion between the first reinforcing layer 30 and the second reinforcing layer 34 can be improved via the first resin layer 21, it is less likely that gaps will form between the first reinforcing layer 30 and the second reinforcing layer 34.

[0094] After the second reinforcement layer 34 has been formed as described above, the high-pressure tank 1 is completed by, as in Fig. Figure 1 shows that valve 6 is attached to the nozzle 4.

[0095] As described above, in this embodiment, the resin layer 21, which covers the cylinder element 31 between the first reinforcing layer 30 and the second reinforcing layer 34, has a lower gas permeability in the thickness direction than the first reinforcing layer 30. Accordingly, the high-pressure tank 1 can be manufactured in a way that reduces leakage of gas passing through the first reinforcing layer 30 to the outside via the second reinforcing layer 34. Therefore, it is not necessary to form a lining on the inner circumferential surface 31b of the cylinder element 31 that has good gas barrier properties.

[0096] Furthermore, as described above, the first resin layer 21 does not form the storage space 5. Even if there is water in the storage space 5, the first resin layer 21 will not come into direct contact with this water. Since this configuration reduces damage to the first resin layer 21 from contact with water, resins, etc., that are easily damaged by water can also be used for the first resin layer 21. This increases the number of material options for the resin layer. For example, a suitable resin with hydrophilic groups as functional groups (e.g., PEN, EVOH, or urethane), etc., can be used. 3. Variation Example

[0097] With reference to the Fig. Sections 11 to 15 describe a variation of the embodiment. The following description focuses on the differences compared to the embodiment above. The same elements and sections as in the embodiment above are designated with the same symbols, but a detailed description of them is omitted.

[0098] In the high-pressure tank 1 of the above embodiment, a portion of the first resin layer 21 is formed in each fitting section 30a between the cylinder element 31 and each coupling element 32, 33. However, the structure of the fitting section 30a is not limited to this.

[0099] For example, the first resin layer 21 can be like in the high-pressure tank 1 of the in the Fig. 11 and Fig. The modification shown in Figure 12 is formed continuously, so that in fitting sections 30b it covers at least a part of each of the outer surfaces 32g, 33g of the dome elements 32, 33. In detail, the first resin layer 21 extends on the outer circumferential surface of a connected element 30B (see Figure 12). Fig. 15) of the cylindrical element 31 and the dome elements 32, 33, which will be described later, such that it covers the boundary sections between the cylindrical element 31 and the dome elements 32, 33. This configuration reduces gas leakage from the boundary sections through the first resin layer 21.

[0100] As in Fig. As shown in Figure 13, in a modified method for manufacturing the high-pressure tank 1, the sequence of the formation step for the first reinforcing layer and the formation step for the first resin layer differs from that of the embodiment described above. The following description focuses on the differences compared to the embodiment described above. In the invention, an element formation step S21, a formation step for the first reinforcing layer S22, and a formation step for the first resin layer S23 correspond to the "production of a connected element."

[0101] In the modified method for manufacturing the high-pressure tank 1, element formation step S21 is similar to element formation step S11 of the exemplary embodiment above. As in Fig. As shown in Figure 14, in the training step for the first reinforcement layer S22, the dome elements 32, 33 are connected with the end sections 31a of the cylinder element 31 to form the connected element 30B before the first resin layer 21 is formed.

[0102] As in Fig. As shown in Figure 13, the training step for the first resin layer S23 is then carried out. As shown in Fig. As shown in Figure 15, in this step the first resin layer 21 is formed on the outer circumferential surface 31c of the cylindrical element 31 in the form of the connected element 30B in a manner similar to that of the formation step for the first resin layer S12 of the above embodiment. Specifically, the first resin layer 21 is formed such that it covers the outer circumferential surface 31c of the cylindrical element 31 and the outer circumferential surfaces of the circumferential end sections 32a, 33a of the dome elements 32, 33.

[0103] As in Fig. As shown in Figure 13, the next step in the training process for the second resin layer S24 is carried out. As shown in the Fig. 15 and Fig. As shown in Figure 11, in this step the second reinforcement layer 34 is formed in a similar manner to that of the formation step for the second reinforcement layer S14 of the above embodiment. In this way, the high-pressure tank 1 can be obtained according to the modification.

Claims

[1] High-pressure tank comprising the following: a first reinforcing layer (30) consisting of a first fiber-reinforced resin; and a second reinforcing layer (34) consisting of a second fiber-reinforced resin and covering the first reinforcing layer (30), wherein the high-pressure tank has a storage space (5) that stores gas, wherein: the first reinforcement layer (30) is a layer which is provided with a cylindrical element (31) and a pair of dome elements (32, 33), wherein the dome elements (32, 33) are connected to respective end sections of the cylindrical element (31) and an inner circumferential surface of the cylindrical element (31) is exposed towards the storage space (5); the second reinforcing layer (34) is a layer consisting of a fiber bundle impregnated with a resin, wherein the fiber bundle is wound spirally over the dome elements (32, 33) of the first reinforcing layer (30); the high-pressure tank also has a resin layer covering the cylinder element (31) between the first reinforcing layer (30) and the second reinforcing layer (34); and the resin layer (21) is less permeable to the gas in one thickness direction than the first reinforcing layer (30), characterized by , that the dome elements (32, 33) are fitted from an outer side of the cylindrical element (31) onto the cylindrical element (31); and in each fitting section where the dome elements (32, 33) are fitted onto the cylinder element (31), a part of the resin layer (21) is located between the cylinder element (31) and the dome element (32, 33). [2] A method for manufacturing a high-pressure tank comprising a first reinforcing layer (30) consisting of a first fiber-reinforced resin and a second reinforcing layer (34) consisting of a second fiber-reinforced resin covering the first reinforcing layer (30), wherein the high-pressure tank has a storage space (5) for storing gas, and the method comprises: Producing a connected element that serves as the first reinforcing layer (30) by connecting a pair of dome elements (32, 33) to a cylindrical element (31) having two end sections such that one of the dome elements (32, 33) is connected to one of the two end sections of the cylindrical element (31) and the other of the dome elements (32, 33) is connected to the other of the two end sections of the cylindrical element (31); and Forming the second reinforcing layer (34) by winding a fiber bundle impregnated with a resin spirally over the dome elements (32, 33) around the fabricated connected element, wherein, in the fabrication of the connected element, the connected element is formed in which a resin layer (21) covers the cylindrical element (31) and an inner circumferential surface of the cylindrical element (31) is exposed towards the storage space (5), and the resin layer (21) is less permeable to the gas in a thickness direction than the first reinforcing layer (30), characterized by , that When manufacturing the connected element in each fitting section where the dome elements (32, 33) are fitted onto the cylinder element (31), a part of the resin layer (21) is formed between the cylinder element (31) and the dome element (32, 33), wherein the fitting sections are formed by fitting the dome elements (32, 33) from an outside of the cylinder element (31) onto the cylinder element (31), the outer circumferential surface of which is covered with the resin layer (21).

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