Hydrogen tank

Abstract

To provide a hydrogen tank capable of reducing the amount of fiber-reinforced resin to be used.SOLUTION: The hydrogen tank includes a mouthpiece having a through-hole, a boss member disposed to face the mouthpiece in an axial direction of the hydrogen tank, a rod-like member assembly in which a plurality of long rod-like members each having one end portion disposed on the mouthpiece side and the other end portion disposed on the boss member side are arranged in a circumferential direction and a radial direction of the hydrogen tank such that the mouthpiece and the boss member serve as winding cores, and a reinforcing layer made of a fiber-reinforced resin disposed to cover an outer peripheral surface of the rod-like member assembly. The rod-shaped members adjacent to each other in the circumferential direction and the radial direction at the one end portion and the other end portion are bonded to each other. The rod-like members adjacent to each other in the circumferential direction and the radial direction at the intermediate portion between the one end portion and the other end portion are respectively arranged so as to have a gap communicating with the through hole of the mouthpiece.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hydrogen tank. [Background technology]

[0002] An example of such a conventional technical field is described in Patent Document 1. The hydrogen tank described in Patent Document 1 includes a liner having a cylindrical body portion and a pair of dome portions provided at both axial ends of the body portion, and a reinforcing layer covering the liner, and the reinforcing layer is formed from a fiber-reinforced resin in which fiber bundles are impregnated with resin. The reinforcing layer has a divided structure, including a body reinforcing layer corresponding to the body portion and a dome reinforcing layer corresponding to the dome portion. The body reinforcing layer and the dome reinforcing layer are bonded together with an adhesive such as epoxy resin in a state in which an end of the body reinforcing layer overlaps an end of the dome reinforcing layer so that the body reinforcing layer is located on the inside and the dome reinforcing layer is located on the outside, respectively. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-043009 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the hydrogen tank described in Patent Document 1, in order to ensure the adhesive strength between the fuselage reinforcement layer and the dome reinforcement layer, it is necessary to increase the area of ​​the overlapping ends of the fuselage reinforcement layer and the dome reinforcement layer (i.e., the adhesive area between the fuselage reinforcement layer and the dome reinforcement layer), which poses the problem of increasing the amount of fiber-reinforced resin used in the reinforcement layer.

[0005] The present invention has been made to solve these technical problems, and has an object to provide a hydrogen tank that can reduce the amount of fiber-reinforced resin used. [Means for solving the problem]

[0006] The hydrogen tank of the present invention comprises a nozzle having a through hole, a boss member arranged opposite the nozzle in the axial direction of the hydrogen tank, a rod-shaped member assembly formed by arranging a plurality of long rod-shaped members, one end of which is arranged on the nozzle side and the other end of which is arranged on the boss member side, in the circumferential and radial directions of the hydrogen tank so that the nozzle and the boss member form a winding core, and a reinforcing layer made of fiber-reinforced resin arranged to cover the outer surface of the rod-shaped member assembly, wherein at the one end and the other end, adjacent rod-shaped members in the circumferential and radial directions are respectively bonded, and at an intermediate portion between the one end and the other end, adjacent rod-shaped members in the circumferential and radial directions are respectively arranged so as to have a gap communicating with the through hole of the nozzle.

[0007] The hydrogen tank according to the present invention comprises a rod-shaped member assembly formed by arranging long rod-shaped members in the circumferential and radial directions of the hydrogen tank with the mouthpiece and boss member as a winding core, and a fiber-reinforced resin reinforcing layer arranged to cover the outer peripheral surface of the rod-shaped member assembly. The rod-shaped member assembly ensures the axial strength of the hydrogen tank, and the reinforcing layer ensures the circumferential strength of the hydrogen tank. This eliminates the need for a dome reinforcing layer, which was required in conventional divided structures, thereby saving the fiber-reinforced resin required for the dome reinforcing layer. Furthermore, since there is no need to bond the fuselage reinforcing layer to the dome reinforcing layer as in conventional structures, there is no increase in the amount of fiber-reinforced resin required to ensure a large bonding area. As a result, the amount of fiber-reinforced resin used can be reduced. In addition, at the intermediate portion between one end and the other end of the rod-shaped member assembly, adjacent rod-shaped members in the circumferential and radial directions of the hydrogen tank are arranged so as to have gaps that communicate with the through-holes in the mouthpiece, allowing hydrogen to be stored by utilizing the gaps between adjacent rod-shaped members.

[0008] In the hydrogen tank according to the present invention, the rod-shaped member preferably has a rod body and cylindrical tabs fitted around both longitudinal ends of the rod body so as to enclose both longitudinal ends of the rod body, and adjacent tabs in the circumferential direction and the radial direction at the one end and the other end are bonded to each other. The cylindrical tabs fitted around both ends of the rod body are thicker than the rod body. By bonding the tabs together, the adhesive strength between adjacent rod-shaped members can be increased and a large gap can be secured between adjacent rod bodies in the middle, thereby increasing the hydrogen storage capacity.

[0009] In the hydrogen tank according to the present invention, it is preferable that a cylindrical liner be disposed between the rod-shaped member assembly and the reinforcing layer, thereby enabling hydrogen gas to be stored more suitably. [Effects of the Invention]

[0010] According to the present invention, the amount of fiber reinforced resin used can be reduced. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing a hydrogen tank according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a hydrogen tank according to the embodiment. [Figure 3] FIG. 2 is a front view showing the nozzle side of the hydrogen tank. [Figure 4] FIG. 1 is a schematic diagram for explaining a manufacturing method of a hydrogen tank (a batch production method in rod units). [Figure 5] FIG. 1 is a schematic diagram for explaining a hydrogen tank (a batch production method using rod tanks as units). [Figure 6] FIG. 1 is a schematic diagram for explaining a manufacturing method of a hydrogen tank (a continuous production method for rod tank units). [Figure 7] 5A to 5C are schematic diagrams for explaining a method for manufacturing a hydrogen tank. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of a hydrogen tank according to the present invention will be described with reference to the drawings. In the description of the drawings, identical elements will be designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, in the following description, unless otherwise specified, "axial direction" refers to the axial direction of the hydrogen tank, "circumferential direction" refers to the circumferential direction of the hydrogen tank, and "radial direction" refers to the radial direction of the hydrogen tank.

[0013] [About hydrogen tanks] Fig. 1 is a perspective view showing a hydrogen tank according to an embodiment, Fig. 2 is a cross-sectional view showing the hydrogen tank according to an embodiment, and Fig. 3 is a front view showing the mouthpiece side of the hydrogen tank. The hydrogen tank 1 according to this embodiment is a tank with a circular cross-section that has an internal space for storing high-pressure hydrogen, and is equipped with a mouthpiece 2 arranged at one end of the hydrogen tank 1, a boss member 3 arranged at the other end of the hydrogen tank 1, a rod-shaped member assembly 4 arranged around the mouthpiece 2 and the boss member 3 so that the mouthpiece 2 and the boss member 3 form a winding core, and a reinforcing layer 5 that covers the outer peripheral surface of the rod-shaped member assembly 4.

[0014] The mouthpiece 2 has a stepped cylindrical shape with a through-hole 21 formed therein, and has a small-diameter portion 22 with a relatively small outer diameter, and a large-diameter portion 23 with a relatively large outer diameter. The large-diameter portion 23 is held in a state where it is surrounded by the rod-shaped member assembly 4. On the other hand, the small-diameter portion 22 is formed integrally with the large-diameter portion 23 and protrudes from the rod-shaped member assembly 4. This small-diameter portion 22 is intended to fit with a valve member (not shown). The through-hole 21 extends in the axial direction L of the hydrogen tank 1 and penetrates the small-diameter portion 22 and the large-diameter portion 23. The mouthpiece 2 having such a structure is formed from a metal material such as stainless steel or an aluminum alloy, or fiber-reinforced plastics (FRP).

[0015] 2, the boss member 3 is disposed opposite the nozzle 2 in the axial direction L. The boss member 3 is cylindrical, and its outer diameter is the same as that of the large diameter portion 23 of the nozzle 2. Like the nozzle 2, the boss member 3 is formed from a metal such as stainless steel or an aluminum alloy, or a fiber-reinforced resin.

[0016] The rod-shaped member assembly 4 is a cylindrical assembly formed by arranging a plurality of long rod-shaped members 40, one end of which is arranged on the mouthpiece 2 side and the other end of which is arranged on the boss member 3 side, in the circumferential and radial directions of the hydrogen tank 1 so that the mouthpiece 2 and the boss member 3 form a winding core. Hereinafter, one end of the rod-shaped member 40 arranged on the mouthpiece 2 side will be referred to as the "mouthpiece-side end 40a," and the other end of the rod-shaped member 40 arranged on the boss member 3 side will be referred to as the "boss member-side end 40b."

[0017] At the mouthpiece-side end 40a and the boss member-side end 40b of the rod-shaped members 40, adjacent rod-shaped members 40 in the circumferential and radial directions of the hydrogen tank 1 are respectively bonded to maintain airtightness. Furthermore, at the intermediate portion 40c between the mouthpiece-side end 40a and the boss member-side end 40b of the rod-shaped members 40, adjacent rod-shaped members 40 in the circumferential and radial directions of the hydrogen tank 1 are respectively arranged so as to have a gap communicating with the through-hole 21 of the mouthpiece 2.

[0018] More specifically, as shown in FIG. 2 , the rod-shaped member 40 has a rod body 41 and cylindrical tabs 42 fitted onto both longitudinal ends of the rod body 41 so as to surround both longitudinal ends of the rod body 41. The rod body 41 is, for example, a round rod with a circular cross section. The tabs 42 are shaped like a square tube with a through-hole formed therein through which the rod body 41 can be inserted. The tabs 42 are fitted onto both longitudinal ends of the rod body 41. One of the tabs 42 fitted onto both longitudinal ends of the rod body 41 constitutes the nozzle-side end 40a of the rod-shaped member 40, and the other constitutes the boss-side end 40b of the rod-shaped member 40.

[0019] Furthermore, at the mouthpiece side end 40a of the rod-shaped member 40, adjacent tabs 42 in the circumferential and radial directions of the hydrogen tank 1 are adhered to each other to maintain airtightness. Similarly, at the boss member side end 40b of the rod-shaped member 40, adjacent tabs 42 in the circumferential and radial directions of the hydrogen tank 1 are also adhered to each other to maintain airtightness.

[0020] As shown in FIG. 3, the rod-shaped members 40 form multiple layers (eight layers in FIG. 3) with the base 2 at the center. More specifically, a first layer consisting of multiple rod-shaped members 40 is arranged closest to the large-diameter portion 23 of the base 2, surrounding the large-diameter portion 23. A second layer consisting of multiple rod-shaped members 40 is arranged outside the first layer, and the third, ..., eighth layers are arranged outside the second layer. In each layer (i.e., in the circumferential direction of the hydrogen tank 1), the tabs 42 of adjacent rod-shaped members 40 are bonded to each other with an adhesive. In addition, in adjacent layers (i.e., in the radial direction of the hydrogen tank 1), the tabs 42 of adjacent rod-shaped members 40 are also bonded to each other with an adhesive. Note that a flexible resin such as an epoxy adhesive is used as the adhesive.

[0021] The reinforcing layer 5 has the function of reinforcing the rod-shaped member assembly 4 and improving the mechanical strength, such as the rigidity and pressure resistance, of the hydrogen tank 1, and has multiple layers formed from fiber-reinforced resin. The fiber-reinforced resin is formed by impregnating a fiber bundle, for example, made of fibers having a diameter of about several μm, with a thermosetting resin or a thermoplastic resin. Examples of the fiber include reinforcing fibers such as carbon fiber, glass fiber, aramid fiber, alumina fiber, boron fiber, steel fiber, PBO fiber, natural fiber, and high-strength polyethylene fiber, and it is particularly preferable to use carbon fiber from the viewpoints of light weight and mechanical strength.

[0022] Examples of thermosetting resins include epoxy resins, modified epoxy resins such as vinyl ester resins, phenolic resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, polyurethane resins, and thermosetting polyimide resins. Examples of thermoplastic resins include polyether ether ketone, polyphenylene sulfide, polyacrylic esters, polyimides, and polyamides.

[0023] The hydrogen tank 1 according to this embodiment includes a rod-shaped member assembly 4 formed by arranging long rod-shaped members 40 in the circumferential and radial directions of the hydrogen tank 1 so that the mouthpiece 2 and boss member 3 form a winding core, and a fiber-reinforced resin reinforcing layer 5 arranged to cover the outer circumferential surface of the rod-shaped member assembly 4. The rod-shaped member assembly 4 ensures the strength of the hydrogen tank 1 in the axial direction L, and the reinforcing layer 5 ensures the strength of the hydrogen tank 1 in the circumferential direction. This eliminates the need for the dome reinforcing layer required in conventional divided structures, thereby saving the fiber-reinforced resin required for the dome reinforcing layer. Furthermore, since there is no longer a need to bond the fuselage reinforcing layer and the dome reinforcing layer as in conventional structures, there is no need to increase the amount of fiber-reinforced resin required to ensure a large bonding area. As a result, the amount of fiber-reinforced resin used can be reduced, thereby reducing the manufacturing cost and weight of the hydrogen tank 1.

[0024] Furthermore, in the intermediate portion 40c between the nozzle side end portion 40a and the boss member side end portion 40b of the rod-shaped member assembly 4, the rod-shaped members 40 adjacent to each other in the circumferential and radial directions are arranged so as to have gaps that communicate with the through holes 21 of the nozzle 2, so that hydrogen can be stored by utilizing the gaps between the adjacent rod-shaped members 40.

[0025] Furthermore, the rod-shaped member 40 has a rod body 41 and cylindrical tabs 42 fitted onto both ends of the rod body 41 so as to enclose both longitudinal ends of the rod body 41, and adjacent tabs 42 in the circumferential and radial directions of the hydrogen tank 1 are bonded to each other at the mouthpiece-side end 40a and boss-side end 40b of the rod-shaped member 40. Because the tabs 42 are thicker than the rod body 41, bonding the tabs 42 to each other increases the adhesive strength between adjacent rod-shaped members 40 and also ensures a large gap between adjacent rod bodies 41 in the middle portion 40c. As a result, the hydrogen storage capacity of the hydrogen tank 1 can be increased.

[0026] Furthermore, since multiple rod-shaped members 40 can be bonded independently, it is possible to increase the bonding area and thereby improve the bonding strength of the rod-shaped members 40. For example, the outer diameter of the tab 42 of the rod-shaped member 40 can be increased or the length of the tab 42 in the direction of the axis L can be increased to increase the outer circumferential area of ​​the tab 42, thereby increasing the bonding area between adjacent tabs 42. Therefore, it is possible to increase the bonding strength between adjacent rod-shaped members 40.

[0027] Furthermore, the hydrogen storage capacity of the hydrogen tank 1 can be easily changed by increasing or decreasing the number of rod-shaped members 40 arranged in the radial direction of the hydrogen tank 1, making it suitable for manufacturing hydrogen tanks of different diameters. Moreover, since there is no need to separately manufacture a dome portion and a dome reinforcing layer to match the outer diameter of the tank as in the past, it is easy to manufacture hydrogen tanks 1 of different diameters.

[0028] Furthermore, because adjacent rod-shaped members 40 are bonded together with a flexible resin such as epoxy adhesive, each rod-shaped member 40 can move slightly in the axial L direction in response to a tensile load in the axial L direction, resulting in uniform tensile stress. Therefore, stress concentration can be alleviated compared to hydrogen tanks with conventional dome reinforcement layers. Furthermore, the reinforcement layer 5 extending in the axial L direction of the hydrogen tank 1 is less susceptible to deformation in the axial L direction, thereby suppressing the occurrence of cracks.

[0029] Furthermore, because the rod-shaped member assembly 4 is composed of an arrangement of multiple rod-shaped members 40, it is easy to install a strain gauge on each rod-shaped member 40 and perform health monitoring of the hydrogen tank 1 based on the detection results of the installed strain gauge. In other words, if a rod-shaped member 40 is damaged, the rigidity of the rod-shaped member 40 decreases, causing the damaged rod-shaped member 40 to pop out of the rod-shaped member assembly 4. By detecting this deformation with a strain gauge, health monitoring of the hydrogen tank 1 can be easily performed.

[0030] In addition to the above, various modifications of the hydrogen tank are possible.

[0031] [Variation 1] For example, a cylindrical liner may be disposed between the rod-shaped member assembly 4 and the reinforcing layer 5. The liner is formed into a cylindrical shape from, for example, a material having gas barrier properties. Examples of such materials include resin materials such as polyethylene and nylon, and metal materials such as aluminum and aluminum alloys. By disposing a liner between the rod-shaped member assembly 4 and the reinforcing layer 5, hydrogen gas can be stored more suitably.

[0032] [Variation 2] Furthermore, the rod-shaped member assembly 4 does not have to have the tabs 42. In this case, for example, the space corresponding to the tabs 42 is filled with adhesive. That is, an adhesive resin is used instead of the tabs 42. Furthermore, as shown in Figs. 5 and 6 described below, a ring member that groups multiple rod-shaped members together in a layered manner can also be used instead of the tabs 42.

[0033] [Variation 3] Furthermore, boss member 3 may have a through-hole that communicates with the gap that stores hydrogen gas. In other words, boss member 3 has the same structure as mouthpiece 2. A hydrogen tank having two mouthpieces in this way can be suitably applied to larger hydrogen tanks.

[0034] [About the manufacturing process of hydrogen tanks] A method for manufacturing a hydrogen tank will be described below. Hydrogen tank manufacturing methods mainly include a rod-unit batch production method (see FIG. 4), a rod-tank unit batch production method (see FIGS. 5 and 7), and a rod-tank unit continuous production method (see FIGS. 6 and 7). Note that "rod" here refers to a rod-shaped member. Note that in FIGS. 4 to 7, the fiber bundle 100 and rod-shaped member 40 may be indicated by dashed lines to make the description easier to understand.

[0035] The rod-unit batch production method is a method applied to the hydrogen tank 1 described in the embodiment, that is, a production method applied to a tank using rod-shaped members 40 having tabs 42. This rod-unit batch production method includes a winding process S11, a hardening and cutting process S12, a tab attachment process S13, and an assembly process S14.

[0036] In the winding step S11, a fiber bundle 100 unwound from a bobbin (not shown) is adjusted in tension by a plurality of rollers 101, and then wound around a rectangular parallelepiped mold 102 made of four connected cylindrical members (see FIG. 4(a)). The fiber bundle 100 is made by bundling carbon fibers, for example, with a diameter of about several μm, and is impregnated with an uncured thermosetting resin (for example, epoxy resin).

[0037] In the curing and cutting step S12, the fiber bundle 100 wound around the mold 102 is transported to a curing oven, where it is cured by heating, and then cut to the length required for the rod-shaped member 40 (see FIG. 4(b)). In the tab attachment step S13, tabs 42 are attached to both ends of each cut fiber bundle 100. The tabs 42 are made of a metal material or a hard resin material. In this way, a rod-shaped member 40 having the rod body 41 and tabs 42 described above is produced (see FIG. 4(c)).

[0038] Here, the fabrication of the reinforcing layer 5 will be described. The reinforcing layer 5 is fabricated by, for example, a filament winding method or a sheet winding method. In the case of the filament winding method, first, a reinforcing layer wound body is formed by winding (hoop winding) a plurality of carbon fiber bundles impregnated with an uncured thermosetting resin (e.g., epoxy resin) around the outer peripheral surface of a cylindrical mandrel. Next, the formed reinforcing layer wound body is cured by heating and then removed from the mandrel. In this way, a cylindrical reinforcing layer 5 is fabricated.

[0039] On the other hand, in the sheet winding method, a fiber sheet having a predetermined width is wound multiple times around the outer peripheral surface of a cylindrical mandrel to form a wound body for the reinforcing layer, and the wound body for the reinforcing layer is hardened by heating and then removed from the mandrel, thereby producing a cylindrical reinforcing layer 5. The fiber sheet used is, for example, a sheet of carbon fibers aligned in one direction and impregnated with a thermosetting resin.

[0040] In the assembly process S14, the rod-shaped members 40 are sequentially attached to the inner wall surface of the cylindrical reinforcing layer 5 to produce the rod-shaped member assembly 4 (see FIG. 4(d)). Specifically, for example, the tabs 42 of the rod-shaped members 40 are sequentially attached to the inner wall surface of the reinforcing layer 5 along the circumferential direction of the reinforcing layer 5 with epoxy adhesive to form the rod-shaped members 40 in the outermost layer (the eighth layer in the example shown in FIG. 3). At this time, the tabs 42 of adjacent rod-shaped members 40 are also bonded to each other with epoxy adhesive. In FIG. 4(d), for ease of understanding, the reinforcing layer 5 is indicated by a two-dot chain line and the rod-shaped members 40 are indicated by a solid line.

[0041] Next, rod-shaped members 40 are attached to the inner wall surfaces of rod-shaped members 40 in the eighth layer with epoxy adhesive, thereby forming rod-shaped members 40 in the seventh layer. At this time, the tabs 42 of adjacent rod-shaped members 40 are also bonded together with epoxy adhesive. This is repeated to form rod-shaped members 40 in the sixth, fifth, ..., and first layers. In this way, the rod-shaped member assembly 4 described above is produced inside the reinforcing layer 5.

[0042] Next, the previously prepared mouthpiece 2 and boss member 3 are inserted into both ends of the prepared rod-shaped member assembly 4, and are bonded to the rod-shaped member assembly 4 with epoxy adhesive. In this way, the above-mentioned hydrogen tank 1 is prepared.

[0043] The rod tank unit batch production method is a production method applied to tanks using rod-shaped members 40 that do not have tabs. The rod tank unit batch production method includes a rod-shaped member assembly forming process S21, a reinforcing layer forming process S22, and an assembly process S23.

[0044] In the rod-shaped member assembly forming step S21, a pair of axially opposing first ring members 103 are prepared. As shown in Fig. 5(a), a plurality of winding protrusions 104 are formed at equal intervals on the outer circumferential edge of each first ring member 103. The first ring member 103 and ring members described below are formed of, for example, a metal material or a hard resin material.

[0045] Next, the fiber bundle 100 is bridged between two opposing first ring members 103 to form a first layer located at the innermost position of the rod-shaped member assembly 4. At this time, the fiber bundle 100 is wound around one winding protrusion 104 of one of the two first ring members 103, and then the fiber bundle 100 is transported toward the other opposing first ring member 103 so as to be parallel to the axial direction, and the fiber bundle 100 is wound around the winding protrusion 104 of the other first ring member 103.

[0046] Next, the fiber bundle 100 is wound around a winding protrusion 104 adjacent to the winding protrusion 104 around which the fiber bundle 100 is wound, and then the fiber bundle 100 is turned back and conveyed toward one of the first ring members 103 (see FIG. 5(a)). The fiber bundle 100 is made by bundling carbon fibers with a diameter of, for example, about several μm, and is impregnated with an uncured thermosetting resin (for example, epoxy resin). The fiber bundle 100 is also configured to be able to move back and forth in the axial direction.

[0047] After the first layer of the rod-shaped member assembly 4 is formed, two second ring members 105 are prepared. The second ring members 105 are formed to have a slightly larger outer diameter than the first ring member 103 so that the first ring member 103 can be fitted inside. Note that the second ring member 105, like the first ring member 103, has a plurality of winding protrusions arranged at equal intervals on its outer circumferential edge.

[0048] Next, a second ring member 105 is fitted onto the first ring member 103 on which the first layer has been formed (see FIG. 5(b)), and then the second layer of the rod-shaped member assembly 4 is formed in the same manner as the first layer (see FIGS. 5(c) and 5(d)). Next, the above-mentioned method is repeated to form the third, fourth, ..., eighth layers in order, and then the layers are hardened by heating. In this way, the rod-shaped member assembly 4 is produced.

[0049] In the reinforcing layer forming step S22, the method for producing the reinforcing layer 5 described in the rod-unit batch production method is used, and the description thereof will be omitted.

[0050] In the assembly step S23, two methods shown in Figures 7(a) and (b) can be used. In the method shown in Figure 7(a), first, an adhesive (e.g., an epoxy adhesive) is applied to the ends of the rod-shaped member assembly 4 produced in the rod-shaped member assembly formation step S21, which will become the nozzle-side end 40a and the boss-member-side end 40b, respectively, to bond adjacent rod-shaped members 40 at these ends. At this time, the adhesive is also applied between adjacent ring members (e.g., between the first ring member 103 and the second ring member 105) and to the outer circumferential surfaces of the rod-shaped member assembly 4 that will be bonded to the reinforcing layer 5 (more specifically, the outer circumferential surfaces of the nozzle-side end 40a and the boss-member-side end 40b). Next, the adhesive-coated rod-shaped member assembly 4 is inserted into the reinforcing layer 5, and the adhesive is allowed to dry, thereby bonding the rod-shaped member assembly 4 and the reinforcing layer 5 together.

[0051] Next, a mouthpiece 2 and a boss member 3, which have been fabricated in advance, are inserted into both ends of the rod-shaped member assembly 4, and the mouthpiece 2 and the boss member 3 are bonded to the rod-shaped member assembly 4 with epoxy adhesive. In this way, a hydrogen tank is fabricated.

[0052] 7(b), first, the rod-shaped member assembly 4 produced in the rod-shaped member assembly forming step S21 is inserted into the reinforcing layer 5 produced in the reinforcing layer forming step S22. Next, an adhesive (e.g., an epoxy adhesive) is injected into the ends that will become the mouthpiece side end 40a and the boss member side end 40b, between the mouthpiece side end 40a and the reinforcing layer 5, and between the boss member side end 40b and the reinforcing layer 5. The adhesive is then dried to bond adjacent rod-shaped members 40 at the mouthpiece side end 40a and the boss member side end 40b, and to bond the rod-shaped member assembly 4 and the reinforcing layer 5 together.

[0053] Next, a mouthpiece 2 and a boss member 3, which have been fabricated in advance, are inserted into both ends of the rod-shaped member assembly 4, and the mouthpiece 2 and the boss member 3 are bonded to the rod-shaped member assembly 4 with epoxy adhesive. In this way, a hydrogen tank is fabricated.

[0054] The rod tank unit continuous production method is a production method applied to tanks using rod-shaped members 40 that do not have tabs. The rod tank unit continuous production method includes a rod-shaped member assembly forming process S31, a reinforcing layer forming process S32, and an assembly process S33.

[0055] The rod-shaped member assembly forming step S31 will be described by taking an example of forming a rod-shaped member assembly 4 having four layers of rod-shaped members 40 as shown in Fig. 6. In this rod-shaped member assembly forming step S31, a fiber bundle 106 for forming a first layer, a fiber bundle 107 for forming a second layer, a fiber bundle 108 for forming a third layer, and a fiber bundle 109 for forming a fourth layer are all prepared for each bobbin. The fiber bundles 106 to 109 are all the same, and are, for example, made by bundling carbon fibers with a diameter of about several µm and impregnated with an uncured thermosetting resin (e.g., epoxy resin).

[0056] The first layer forming fiber bundle 106, the second layer forming fiber bundle 107, the third layer forming fiber bundle 108, and the fourth layer forming fiber bundle 109 are prepared in the required numbers, and are arranged so as to form a circular tunnel. For example, if 25 rod-shaped members 40 are required to form the first layer of the rod-shaped member assembly 4, 31 rod-shaped members 40 to form the second layer, 37 rod-shaped members 40 to form the third layer, and 43 rod-shaped members 40 to form the fourth layer, then 25 fiber bundles 106, 31 fiber bundles 107, 37 fiber bundles 108, and 43 fiber bundles 109 are prepared.

[0057] As shown in Fig. 6, 25 fiber bundles 106 are arranged on the innermost side and are evenly arranged so as to form a tunnel with a circular cross section along the outer periphery of the central ring 110. Outside the 25 fiber bundles 106, 31 fiber bundles 107, which form the second layer, are arranged in a tunnel shape. Outside the 31 fiber bundles 107, 37 fiber bundles 108 are arranged in a tunnel shape, and outside the 37 fiber bundles 108, 43 fiber bundles 109 are arranged in a tunnel shape (see Fig. 6(a)).

[0058] Next, two semicircular ring members 111 that can be fitted together are arranged from the outside (for example, both the left and right sides) of the 25 fiber bundles 106 that will form the first layer so as to bind the 25 fiber bundles 106, and are fitted so as to be externally inserted into the central ring 110. In this way, the first layer of the rod-shaped member assembly 4 is formed (see FIG. 6(b)).

[0059] Next, two semicircular ring members 112 that can be fitted together are arranged from the outside (for example, both the left and right sides) of the 31 fiber bundles 107 that will form the second layer, so as to bind the 31 fiber bundles 107. The semicircular ring members 112 are formed to have a size that allows the pair of semicircular ring members 111 fitted inside them to be inserted when fitted together. Thereafter, the pair of semicircular ring members 112 are fitted together so as to be fitted outside the fitted semicircular ring members 111. This forms the second layer of the rod-like member assembly 4 (see FIG. 6(c)).

[0060] Next, two semicircular ring members 113 that can be fitted together are arranged from the outside (for example, both the left and right sides) of the 37 fiber bundles 108 that will form the third layer, so as to bind the 37 fiber bundles 108 (see FIG. 6(d)). Note that the semicircular ring members 113 are formed to have a size that allows the pair of semicircular ring members 112 fitted inside them to be inserted when fitted together. Thereafter, the pair of semicircular ring members 113 are fitted together so as to be fitted onto the fitted semicircular ring members 112. In this way, the third layer of the rod-shaped member assembly 4 is formed.

[0061] Next, the 43 fiber bundles 109 are evenly arranged so as to form a tunnel with a circular cross section along the outer periphery of the fitted pair of semicircular ring members 113. This forms the third layer of the rod-shaped member assembly 4 (see FIG. 6(e)).

[0062] Then, by repeating the above process, a continuous rod-shaped member assembly 4 is formed as shown in Fig. 6(f). Next, the continuous rod-shaped member assembly 4 is transported to a curing furnace 114, where the thermosetting resin impregnated in the fiber bundles 106 to 109 is cured. After that, the continuous rod-shaped member assembly 4 is cut to the required length. In this way, the rod-shaped member assembly 4 is produced.

[0063] The reinforcing layer forming process S32 uses the same method for producing the reinforcing layer 5 as described in the rod-unit batch production method, and its description will be omitted. Also, the assembly process S33 is the same as the assembly process S23 described in the rod-tank unit batch production method, and its description will be omitted.

[0064] Through the above steps, a hydrogen tank is produced.

[0065] The present invention will be described below with reference to examples, but the present invention is not limited to the scope of the examples.

[0066] [Example] In the examples, the hydrogen tank 1 (product of the present invention) described in the above embodiment was fabricated. The total weight of the fabricated product of the present invention, the weight of the CFRP (carbon fiber reinforced plastic) used, and the mass efficiency were each investigated. The results are summarized in Table 1. The mass efficiency is the ratio of the weight of hydrogen filled to the total weight of the hydrogen tank.

[0067] [Comparative Example] As a comparative example, a conventional hydrogen tank (conventional product) was fabricated with a reinforcement layer that included a dome reinforcement layer corresponding to the dome portion of the liner and a fuselage reinforcement layer corresponding to the fuselage portion of the liner. When bonding the dome reinforcement layer and the fuselage reinforcement layer, the ends of the dome reinforcement layer and the fuselage reinforcement layer were overlapped to form an adhesive area. The total weight, the weight of the CFRP used, and the mass efficiency of the fabricated conventional product were then investigated in the same manner as in the examples. The results are summarized in Table 1.

[0068] [Table 1]

[0069] As shown in Table 1, compared to conventional products, the product of the present invention uses less CFRP, can hold more hydrogen than conventional products, and has a smaller overall weight. Furthermore, the volumetric efficiency was improved by 7% compared to conventional products. Therefore, the hydrogen tank of the present invention has been shown to be effective in reducing the amount of fiber-reinforced resin used.

[0070] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as set forth in the claims. [Explanation of symbols]

[0071] 1: hydrogen tank, 2: nozzle, 3: boss member, 4: rod-shaped member assembly, 5: reinforcing layer, 21: through-hole, 22: small diameter portion, 23: large diameter portion, 40: rod-shaped member, 40a: nozzle-side end, 40b: boss member-side end, 40c: middle portion, 41: rod body, 42: tab

Claims

1. A hydrogen tank, a nozzle having a through hole; a boss member disposed opposite the nozzle in the axial direction of the hydrogen tank; a rod-shaped member assembly formed by arranging a plurality of long rod-shaped members, one end of which is disposed on the mouthpiece side and the other end of which is disposed on the boss member side, in the circumferential direction and the radial direction of the hydrogen tank so that the mouthpiece and the boss member form a winding core; a reinforcing layer made of fiber reinforced resin and arranged to cover the outer peripheral surface of the rod-shaped member assembly; Equipped with At the one end and the other end, the rod-shaped members adjacent to each other in the circumferential direction and the radial direction are bonded to each other, A hydrogen tank characterized in that, in the intermediate portion between the one end and the other end, adjacent rod-shaped members in the circumferential direction and the radial direction are arranged so as to have gaps that communicate with the through holes of the nozzle.

2. The rod-shaped member has a rod body and cylindrical tabs fitted onto both ends of the rod body so as to enclose both ends of the rod body in the longitudinal direction, 2. The hydrogen tank according to claim 1, wherein the tabs adjacent to each other in the circumferential direction and the radial direction at the one end and the other end are bonded to each other.

3. 2. The hydrogen tank according to claim 1, wherein a cylindrical liner is disposed between the rod-shaped member assembly and the reinforcing layer.

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