high-pressure tank

Abstract

A high-pressure tank is provided. The high-pressure tank provides improved strength and rigidity by optimizing the lamination pattern and structure of a fiber-reinforced plastic forming a bulge portion of the high-pressure tank used in a fuel tank of a fuel cell vehicle. The fiber-reinforced plastic, which has relatively high strength, is blended and used for a weak portion of a bulge portion of a support layer of a high-pressure tank where stress caused by internal pressure of the high-pressure tank is concentrated. Specifically, burst strength and rigidity are increased. The use amount of the fiber-reinforced plastic, the number of windings, and a thickness are reduced by directly reinforcing a weak point of the bulge portion. Consequently, the manufacturing cost of the high-pressure tank is reduced.

Description

BACKGROUND(a) Technical field

[0001] The present disclosure relates to a high-pressure tank, and more particularly to a high-pressure tank that provides improved strength and rigidity reinforcement by optimizing a lamination pattern and structure of a fiber-reinforced plastic constituting the tank. (b) Description of the related art

[0002] A fuel cell vehicle that uses hydrogen as fuel typically contains a high-pressure fuel tank for storing hydrogen in the form of a high-pressure gas. The high-pressure fuel tank includes an inner lining layer that prevents gas penetration and an outer support layer that stores or absorbs the tank's internal pressure. The lining layer is made of a plastic material, and the support layer is made of an expensive fiber-reinforced plastic.

[0003] For example, the carbon fiber reinforced plastic used for the support layer of a high-pressure fuel tank is a composite material formed using carbon fiber as the reinforcing fiber. This carbon fiber reinforced plastic can be used to produce a composite body that is lightweight and has improved strength and elasticity. However, compared to carbon steel, carbon fiber reinforced plastic is a costly material with increased costs. Fiber reinforced plastic is an anisotropic material that exhibits varying strength based on a fiber lamination pattern. If the lamination pattern is compromised, high strength cannot be maintained even if a significant amount of the material is used.

[0004] In this context, US Pat. No. 4,699,288 A discloses a high-pressure vessel construction in the form of an elongated tank comprising a plurality of layers of resin-impregnated graphite fibers and a plurality of layers of a hybrid of resin-impregnated glass and polymer fibers, with the glass and polymer fiber layers alternating with the graphite fiber layers. The outermost layers are wound in a ring shape, and the innermost layers are wound helically. A layer of elastomeric material is bonded to the inner surface of the innermost fiber layer, and a layer of rigid composite material is bonded to the inner surface of the elastomer layer.Furthermore, US 5,385,263 A discloses lightweight compressed gas cylinders housed in a module containing a distribution system and designed for easy loading, unloading, and transport on a flatbed trailer or other vehicle, in particular a hooklift, a specialized vehicle for the mechanical transport of large containers. The module eliminates the need to leave the vehicle itself at the site. A variety of cylinders made of composite materials can be used to achieve low weight, but certain novel composite cylinders are also disclosed that are particularly useful. These cylinders have a lightweight metallic liner or core cylinder wrapped with three layers of wound fibers. The inner and outer layers consist of axially wound glass fibers, and the intermediate layer is of braided carbon fiber.

[0005] JP 2010-270878 A describes a high-pressure tank comprising: a support layer defining an outer layer of the high-pressure tank and including a cylinder portion at a center thereof, wherein the cylinder portion is formed to have a structure in which ring layers and spiral layers, which are layered on an outer surface of a liner layer, are alternately layered, and wherein the ring layer, which is arranged under the ring layers and the spiral layers, is layered first to position the outer surface of the liner layer in direct contact with the ring layer;and bulge portions formed on both sides of the cylinder portion, the bulge portion including an inner spiral layer portion that is an inner layer and an outer spiral layer portion that is an outer layer, the inner spiral layer portion including a plurality of low-angle spiral layers, and at least one inner spiral layer of the plurality of inner spiral layers is a high-strength inner spiral layer having greater rigidity than the other inner spiral layers.

[0006] US 2013 / 0 087 567 A1 also discloses a high-pressure container for storing a liquid, comprising: a liner; and a fiber-reinforced resin layer configured to contain a fiber and cover the surface of the liner. The liner includes: a cylindrical liner portion having a cylindrical shape; and dome-shaped liner portions connected to respective sides of the cylindrical liner portion, each dome-shaped liner portion being connected to the cylindrical liner portion such that an outer surface of the dome-shaped liner portion is inclined at a predetermined angle to an outer surface of the cylindrical liner portion.The fiber-reinforced resin layer includes a tire layer formed on the outer surface of the cylindrical liner member to cover the outer surface of the cylindrical liner member, and provided by a tire winding that winds the fiber substantially perpendicular to a central axis of the cylindrical liner member. The tire layer is formed such that an outer surface of the tire layer, at a boundary between the tire layer and the dome liner member, has an angle smaller than the predetermined angle with the outer surface of the dome liner member.

[0007] The above information disclosed in this section is intended only to enhance the understanding of the background of the disclosure and may therefore contain information that does not constitute prior art already known to someone of ordinary skill in the art in this country. SUMMARY

[0008] It is therefore the object of the present disclosure to provide a high-pressure tank with improved strength and rigidity reinforcement by optimizing a lamination pattern and a structure of a fiber-reinforced plastic for forming a dome portion of the high-pressure tank for use in a fuel tank of a fuel cell vehicle or the like.

[0009] The problem is solved by a high-pressure tank having the features of claim 1. Advantageous further developments can be found in the subclaims.

[0010] In an exemplary embodiment, a high-pressure tank may include a support layer having an outer layer of the high-pressure tank including a cylindrical portion at a center thereof, wherein the cylindrical portion is formed to have a structure in which ring layers and spiral layers, which are layered on an outer surface of a liner layer, are alternately layered, and wherein the ring layer, which is arranged among the ring layers and the spiral layers, is layered first to position the outer surface of the liner layer in direct contact with the ring layer. Bulge portions may be formed on both sides of the cylindrical portion. The bulge portion may include a shallow-angled inner spiral layer portion constituting an inner layer and a shallow-angled outer spiral layer portion constituting an outer layer.The low-angle inner spiral layer portion may include a plurality of low-angle inner spiral layers. At least one low-angle inner spiral layer of the plurality of low-angle inner spiral layers may be a high-strength low-angle inner spiral layer having greater rigidity than the low-angle inner spiral layers.The at least one flat-angled inner spiral layer is formed from a fiber-reinforced plastic having a relatively higher strength and rigidity than fiber-reinforced plastics of any other of the plurality of flat-angled inner spiral layers of the portion of the flat-angled inner spiral layer or of any layer of the flat-angled outer spiral layers, and the at least one flat-angled inner spiral layer, which has a greater stiffness and strength than any other of the plurality of flat-angled inner spiral layers, is arranged as a layer within a thickness range corresponding to approximately 15 to 25% of the thickness of the arched portion such that the at least one flat-angled inner spiral layer completely wraps around the arched portions in the thickness range.

[0011] In an exemplary embodiment, the low-angle inner spiral layer portion may be formed into a thickness range corresponding to approximately 5% to 30% of a total thickness of the bulge portion. The low-angle outer spiral layer portion may be formed into a thickness range corresponding to approximately 70% to 95% of a total thickness of the bulge portion. In an exemplary embodiment, a portion of the plurality of low-angle inner spiral layers of the low-angle inner spiral layer portion may be high-strength low-angle inner spiral layers having greater stiffness than the remaining low-angle inner spiral layers, which may be low-stiffness low-angle inner spiral layers.

[0012] For example, the high-strength, low-angle inner spiral layers may be arranged as inner layers of the low-angle inner spiral layer section. The low-strength, low-angle inner spiral layers may be arranged as outer layers of the low-angle inner spiral layer section. In another exemplary embodiment, the high-strength, low-angle inner spiral layers may be arranged as outer layers of the low-angle inner spiral layer section. The low-strength, low-angle inner spiral layers may be arranged as inner layers of the low-angle inner spiral layer section.

[0013] In some exemplary embodiments, the low-angle inner spiral layer with high strength and the low-angle inner spiral layer with low strength may be arranged in an intermixed manner without limiting the layering order, or may be arranged in an intermixed manner in which the layers are alternately layered. According to an exemplary embodiment, fiber-reinforced plastics with improved strength compared to conventional plastics may be intermixed and used for a weak portion of a bulge portion of a support layer of a high-pressure tank where stress caused by internal pressure of the tank is concentrated. Consequently, the burst strength and rigidity can be increased, and the usage amount of the fiber-reinforced plastic can be reduced.The number of windings can be reduced by directly reinforcing a weak point of the bulge section and the manufacturing cost of the high-pressure tank can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above-mentioned and other features of the present disclosure will now be described in detail with reference to exemplary embodiments thereof illustrated in the accompanying drawings, which are given below for illustrative purposes only and thus do not limit the present disclosure, and in which: Fig. 1 is an exemplary cross-sectional view illustrating a high-pressure tank according to an exemplary embodiment of the present disclosure; Fig. 2 is an exemplary enlarged view showing part A in Fig. 1 according to an exemplary embodiment of the present disclosure; Fig. 3 is an exemplary enlarged view showing part B in Fig. 1 according to an exemplary embodiment of the present invention; the Fig. 4A to 4H are exemplary views illustrating a portion of a low-angle inner spiral layer according to the exemplary embodiment of the present disclosure; Fig. 5 is an exemplary enlarged view showing part C in Fig. 1 according to an exemplary embodiment of the present disclosure; the Fig. 6A-6C are exemplary conceptual views illustrating types of winding patterns for the high-pressure tank according to the exemplary embodiment of the present disclosure; Fig.7 is an exemplary graph illustrating a burst pressure of the high-pressure tank with respect to positions of a low-angle inner spiral layer having a high strength formed by winding a fiber-reinforced plastic having a high strength, according to an exemplary embodiment of the present disclosure; and Fig. 8 is an exemplary graph illustrating a burst pressure of the high-pressure tank with respect to usage ranges of a strength range of a bulge portion in which the low-angle inner spiral layer having a high strength is used, according to an exemplary embodiment of the present disclosure.

[0015] The reference numbers shown in the drawings include reference to the following elements, which are further discussed below: 100 high-pressure tank 110 lining layer 112 metal attachment 120 carrier layer 122 cylinder section 122a ring layer 122b Spiral layer 124 vault section 126a Section from a flat-angled inner spiral layer 126aa Low-angle inner spiral layer with high strength 126ab Low-angle inner spiral layer with low strength 126b Section from a flat-angled outer spiral layer 128 Transition section

[0016] It should be understood that the accompanying drawings are not necessarily to scale and present a somewhat simplified representation of various features illustrative of the basic principles of the disclosure. The specific embodiments of the present disclosure disclosed herein, including, for example, particular dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and environment of use. In the figures, reference numerals refer to like or equivalent parts of the present disclosure throughout the several figures of the drawings. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to various embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings and described below. While the disclosure will be described in connection with exemplary embodiments, it will be understood that the present description is not intended to limit the disclosure to these exemplary embodiments. On the contrary, the disclosure is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other exemplary embodiments that may be included within the spirit and scope of the disclosure as defined by the appended claims.

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a" and "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of the recited features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements.For example, to clarify the description of the present invention, unrelated parts are not shown, and the thicknesses of layers and regions are exaggerated for clarity. Furthermore, when a layer is stated to be "on" another layer or substrate, the layer may be directly on another layer or substrate, or a third layer may be interposed between them.

[0019] It will also be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of the recited features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0020] Unless specifically stated or obvious from the context, the term "approx." as used herein is to be understood as within a range of normal tolerance in the art, for example, within 2 standard deviations of the mean. "Approx." may be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from the context, all numerical values ​​provided herein are modified by the term "approx."

[0021] It is to be understood that the term "vehicle" or "vehicular" or other similar term used herein includes motor vehicles in general, such as passenger cars, including off-road vehicles (SUVs), buses, trucks, various business cars, watercraft, including a variety of boats and vessels, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from feedstocks other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more power sources, such as both gasoline-powered and electric-powered vehicles.

[0022] Hereinafter, an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. As in Fig. 1, a high-pressure tank 100 according to the present disclosure may include a liner layer 110, which is an inner layer and can prevent or block the penetration of fuel in the form of a high-pressure gas, and a support layer 120, which is an outer layer and receives the tank internal pressure, and a metal boss 112 integrally arranged on an inlet side of the liner layer 110 and connected to an opening and closing valve (not illustrated).

[0023] The lining layer 110 may be formed by injection molding a plastic material. The metal boss 112 may be integrally formed on the inlet side of the lining layer 110 by inserting the metal boss 112 into an injection mold and performing injection molding. The support layer 120 may be formed by a winding-lamination method for winding and laminating a fiber-reinforced plastic around an outer surface of the lining layer 110 and may include a cylinder portion 122 at a center thereof. Curved portions 124 may be integrally formed on both sides of the cylinder portion 122. The cylinder portion 122 may be a substantially straight portion of the high-pressure tank 100 and may be formed into a cylindrical shape along an outer shape of a center portion of the lining layer 110. As shown in Fig.2, the cylinder portion 122 may have a cross-sectional structure in which ring layers 122a and spiral layers 122b, which are formed by winding the fiber-reinforced plastic around the outer surface of the central portion of the liner layer 110, are alternately layered.

[0024] In particular, the ring layers 122a and the spiral layers 122b can each be formed by winding the fiber-reinforced plastic once around the outer surface of the lining layer 110 or by winding the fiber-reinforced plastic several times around the outer surface of the lining layer 110. In other words, the ring layers 122a and the spiral layers 122b, which are shown in Fig.2, by wrapping the fiber-reinforced plastic at least once around the outer surface of the lining layer 110. The configuration in which the annular layer 122a is disposed in an inner layer region of a thickness range of the carrier layer 120 and is layered more adjacent to the lining layer 110 may be advantageous for increasing the burst strength of the high-pressure tank 100. Consequently, the annular layer 122a and the spiral layers 122b of the cylinder portion 122 may be initially layered on the outer surface of the central portion of the lining layer 110 to be in (e.g., direct) contact with the outer surface of the central portion of the lining layer 110.

[0025] Regarding the Fig.6A-6C, the ring layers 122a may be formed by stacking them in a winding pattern in which the fiber-reinforced plastic may be wound around the outer surface of the liner layer 110. In other words, the fiber-reinforced plastic may be wound at an approximately right angle with respect to a direction L of a central axis of the high-pressure tank 100 (e.g., an axial direction of the liner layer 110). The spiral layers 122b may be formed by stacking them in a winding pattern in which the fiber-reinforced plastic wound around the outer surface of the liner layer 110 is wound at an acute angle within a predetermined range with respect to the direction L of the central axis of the high-pressure tank 100.

[0026] Specifically, the ring layers 122a can be formed by stacking them in a ring pattern in which the fiber-reinforced plastic is wound at an angle of approximately 89° with respect to the direction L of the central axis of the high-pressure tank 100. The spiral layers 122b can be formed by stacking them in a steep-angle spiral pattern in which the fiber-reinforced plastic is wound at an acute angle of approximately 45° to 88° with respect to the direction L of the central axis of the high-pressure tank 100, or by stacking them in a shallow-angle spiral pattern in which the fiber-reinforced plastic is wound at an acute angle of approximately α to 44° with respect to the direction L of the central axis of the high-pressure tank 100. For example, α may be a minimum winding angle of the fiber-reinforced plastic and α may be based on values ​​of an outer diameter z of the lining layer 110 and an outer diameter rb of the metal projection 112. In other words, the minimum winding angle of the fiber-reinforced plastic forming the flat-angle spiral pattern can be determined based on α=sin -1 (r b / z) can be determined.

[0027] The bulge portions 124 may be curved portions of the high-pressure tank 100 and formed into an approximately hemispherical shape along outer shapes of both end portions of the lining layer 110. As shown in Fig.3, the bulge portions 124 can be formed by wrapping the fiber-reinforced plastic around the outer surfaces of both end portions of the lining layer 110 (e.g., the outer surfaces of both end portions of the lining layer 110 and an outer surface of the metal boss 112) several times. Specifically, for the bulge portion 124, in order to directly enhance rigidity and strength, to reinforce bursting rigidity and bursting strength without increasing a thickness of the bulge portion or using a separate reinforcing member, the fiber-reinforced plastic having a relatively high strength can be used for a portion selected when the bulge portion 124 is formed by wrapping the fiber-reinforced plastic.

[0028] Furthermore, based on a thickness direction of the bulge portion 124, the bulge portion 124 may include a low-angle inner spiral layer portion 126a, which is the inner layer, and a low-angle outer spiral layer portion 126b, which is the outer layer. The fiber-reinforced plastic may have relatively high rigidity and strength and may be used for the low-angle inner spiral layer portion 126a, which is adjacent to the outer surfaces of both end portions of the liner layer 110 and the outer surface of the metal boss 112. The low-angle inner spiral layer portion 126a may include a plurality of low-angle inner spiral layers.At least one low-angle inner spiral layer of the low-angle inner spiral layers can be formed using the fiber-reinforced plastic having greater rigidity and strength than the fiber-reinforced plastic of the other low-angle inner spiral layers.

[0029] In other words, the low-angle inner spiral layer portion 126a may include at least one high-strength low-angle inner spiral layer 126aa formed by wrapping the fiber-reinforced plastic, which may have greater stiffness and strength than a fiber-reinforced plastic of the low-angle outer spiral layer portion 126b and may have greater stiffness and strength than a fiber-reinforced plastic of the other low-angle inner spiral layers (e.g., a low-strength low-angle inner spiral layer), around the outer surfaces of the liner layer 110 and the metal boss 112.For example, a low-strength, low-angle inner spiral layer 126ab and a high-strength, low-angle inner spiral layer 126aa may be formed by wrapping the fiber-reinforced plastic around the outer surfaces of the liner layer 110 and the metal boss 112.

[0030] Since the high-strength and high-rigidity fiber-reinforced plastic can be used for at least a portion of the low-angle inner spiral layer portion 126a of the bulge portion 124, which is an inner layer, the amount of use of the expensive high-strength fiber-reinforced plastic can be reduced, and the reinforcement of the strength and rigidity of the bulge portion 124 can be improved. When the bulge portions 124 are formed into a multi-layered shape by winding the fiber-reinforced plastic around the outer surfaces of both end portions of the liner layer 110 and the outer surface of the metal boss 112, the low-angle inner spiral layer portion 126a can be formed by winding the fiber-reinforced plastic.

[0031] The low-angle outer spiral layer portion 126b can be formed by winding the fiber-reinforced plastic. Specifically, the bulge portion 124 includes the low-angle inner spiral layer portion 126a, which can be formed into an inner layer region adjacent to the outer surface of the liner layer 110 in the thickness direction of the bulge portion 124. The low-angle outer spiral layer portion 126b can be formed into an outer layer region in the thickness direction of the bulge portion 124 by laminating it outside the low-angle inner spiral layer portion 126a.

[0032] Typically, the inner layer region of the bulge portion 124, in which the fiber-reinforced plastic is first wrapped around the outer surface of the liner layer 110, is structurally deteriorated by the internal pressure of the high-pressure tank 100 compared to the outer layer region. Consequently, the inner layer region is weakened due to stress concentrated in the inner layer region. Since the low-angle inner spiral layer portion 126a including at least one low-angle inner spiral layer 126aa with high strength can be formed in the inner layer region of the bulge portion 124 as described above, the strength of the weak portion of the bulge portion 124 can be improved.

[0033] In other words, the overall strength of the bulge portion 124 can be enhanced by using the fiber-reinforced plastic having relatively high strength and rigidity in at least one portion of the bulge portion 124. In particular, since the fiber-reinforced plastic having enhanced strength and rigidity can be used for the low-angle inner spiral layer portion 126a constituting the inner layer portion of the bulge portion 124, it is possible to more effectively enhance the strength of the bulge portion 124 compared to the fiber-reinforced plastic having high strength and rigidity used for the low-angle outer spiral layer portion 126b.

[0034] In general, the number of layers of fiber-reinforced plastic (e.g., the number of windings) can be increased to improve the weakness of the bulge portion 124, and thus, the strength of the bulge portion can be increased. If the number of layers of fiber-reinforced plastic is merely increased, the reinforcement effect may be insufficient compared to the amount of fiber-reinforced plastic used. Consequently, a significant amount of fiber-reinforced plastic may be required for use, causing a significant increase in manufacturing costs.

[0035] Therefore, as described above, since the low-angle inner spiral layer portion 126a in the inner layer region, which is a structurally weak portion of the bulge portion 124, is formed using the fiber-reinforced plastic having higher rigidity and strength than the fiber-reinforced plastic of the low-angle outer spiral layer portion 126b, stress can be prevented from being concentrated on the bulge portion 124. Furthermore, compared with the related art, the use amount of the fiber-reinforced plastic can be reduced to reduce the strength of the bulge portion 124, ensuring the reinforcement effect at the same level as that of a conventional bulge portion (e.g., a bulge portion made of a single fiber-reinforced plastic).

[0036] Furthermore, a detailed structure of the portion 126a of a flat-angled inner spiral layer with respect to the Fig. 4A to 4H. The enclosed Fig. 4A to 4D are views illustrating the low-angle inner spiral layer portion 126a according to the exemplary embodiment of the present disclosure. As shown in FIGS. Fig.4A-4C, the low-angle inner spiral layer portion 126a may include the plurality of low-angle inner spiral layers. One low-angle inner spiral layer of the plurality of low-angle inner spiral layers may be configured as the high-strength low-angle inner spiral layer 126aa, which has relatively greater stiffness and strength than the other low-angle inner spiral layers. In other words, the high-strength low-angle inner spiral layer 126aa may be disposed as a lowermost layer of the low-angle inner spiral layer portion 126a and may be in (e.g., direct) contact with the outer surface of the liner layer 110 and the outer surface of the metal boss 112 ( Fig.4A). The low-angle inner spiral layer 126aa having a high strength may be arranged as a topmost layer of the low-angle inner spiral layer portion 126a ( Fig. 4B) or as any layer between the lowest layer and the highest layer ( Fig. 4C).

[0037] As in the Fig.4D-4E illustrates, two or more shallow-angle inner spiral layers of the plurality of shallow-angle inner spiral layers of the shallow-angle inner spiral layer portion 126a may be the high-strength shallow-angle inner spiral layer 126aa, which has relatively greater stiffness and strength than the remaining shallow-angle inner spiral layers. In other words, some layers of the plurality of shallow-angle inner spiral layers of the shallow-angle inner spiral layer portion 126a may be the high-strength shallow-angle inner spiral layer 126aa. The remaining shallow-angle inner spiral layers may be the low-strength shallow-angle inner spiral layers 126ab.

[0038] In other words, based on the thickness direction of the low-angle inner spiral layer portion 126a, all the low-angle inner spiral layers 126aa having a high strength may be arranged in the inner layer region of the low-angle inner spiral layer portion 126a, and all the low-angle inner spiral layers 126ab having a low strength may be arranged in the outer layer region of the low-angle inner spiral layer portion 126a ( Fig.4D). Alternatively, based on the thickness direction of the low-angle inner spiral layer portion 126a, the high-strength low-strength inner spiral layers 126aa may be arranged in the outer layer region of the low-angle inner spiral layer portion 126a. The low-strength low-strength inner spiral layers 126ab may be arranged in the inner layer region of the low-angle inner spiral layer portion 126a ( Fig. 4E).

[0039] In other words, the total thickness of the low-angle inner spiral layers 126aa with a high strength may be equal to or different from the total thickness of the low-angle inner spiral layers 126ab. As shown in the Fig.4F-4G, in the shallow-angle inner spiral layer portion 126a, the plurality of high-strength shallow-angle inner spiral layers 126aa and the plurality of low-strength shallow-angle inner spiral layers 126ab may be arranged in an intermingled manner without limiting the layer stacking order (e.g., the order of winding the fiber-reinforced plastic). The high-strength shallow-angle inner spiral layers 126aa and the low-strength shallow-angle inner spiral layers 126ab may be arranged in an intermingled manner in which the high-strength shallow-angle inner spiral layers 126aa and the low-strength shallow-angle inner spiral layers 126ab may be stacked sequentially and alternately.In particular, the low-angle inner spiral layer 126aa having a high strength or the low-angle inner spiral layer 126ab having a low strength may be arranged as a lowermost layer of the low-angle inner spiral layer portion 126a.

[0040] As in Fig.4H, all of the layers of the plurality of low-angle inner spiral layers constituting the low-angle inner spiral layer portion 126a may be the high-strength low-angle inner spiral layer 126aa. Specifically, the low-angle inner spiral layers (e.g., the high-strength low-angle inner spiral layers and the low-strength low-angle inner spiral layers) of the low-angle inner spiral layer portion 126a may be formed by stacking them in a winding pattern in which the fiber-reinforced plastic wound around the outer surface of the liner layer 110 can be wound at an acute angle within a predetermined range with respect to the central axis direction L of the high-pressure tank 100.In particular, the shallow-angled inner spiral layers may be formed by stacking them in a shallow-angled spiral pattern in which the fiber-reinforced plastic is wound at an acute angle of approximately α to 44° with respect to the direction L of the center axis of the high-pressure tank 100 (. Fig. 6C). When the shallow-angled inner spiral layers are wound as described above, a section of the spiral layers of the cylinder portion 122 can be formed simultaneously.

[0041] The low-angle inner spiral layer portion 126a and the low-angle outer spiral layer portion 126b can be formed using different fiber-reinforced plastics (e.g., a composite material using carbon fiber as the reinforcing fiber and a composite material using glass fiber as the reinforcing fiber). Some layers of the low-angle inner spiral layers of the low-angle inner spiral layer portion 126a can be formed using the fiber-reinforced plastic having relatively greater strength and rigidity than the fiber-reinforced plastics of the other low-angle inner spiral layers and the low-angle outer spiral layers. Therefore, the amount of fiber-reinforced plastic used and the strength of the bulge portion 124 can be reduced.Furthermore, the weight and manufacturing cost of the high-pressure tank can be reduced, and fuel-to-weight efficiency can be improved due to the reduction in the weight of the high-pressure tank 100. The supply amount of fuel stored in the high-pressure tank 100 can be increased, thus increasing or extending the distance a vehicle can travel.

[0042] Since at least one shallow-angle inner spiral layer of the plurality of shallow-angle inner spiral layers constituting the shallow-angle inner spiral layer portion 126a of the bulge portion 124 may be the shallow-angle inner spiral layer 126aa having high strength, the inner layer region (e.g., the shallow-angle inner spiral layer portion) of the bulge portion 124 may have greater burst strength and rigidity than the outer layer region (e.g., the shallow-angle outer spiral layer portion). In the bulge portion 124, approximately 5% to 30% of the total thickness of the shallow-angle inner spiral layer portion 126a, which is the inner layer, and the shallow-angle outer spiral layer portion 126b, which is the outer layer, may be formed as the shallow-angle inner spiral layer portion 126a, and approximately70% to 95% of the total thickness as section 126b is formed from a low-angle outer spiral layer.

[0043] If the thickness of the low-angle inner spiral layer portion 126a is less than approximately 5% of the total thickness of the bulge portion 124, it may be difficult to increase the strength and rigidity of the bulge portion 124 to a desired level. If the thickness of the low-angle inner spiral layer portion 126a is more than approximately 30% of the total thickness of the bulge portion 124, the effect of increasing the strength and rigidity of the bulge portion 124 is not improved in terms of cost. Since the fiber-reinforced plastic with greater strength and greater rigidity is expensive, it is usually necessary to increase the strength and rigidity of the bulge portion 124 while minimizing the use of the fiber-reinforced plastic with high strength.

[0044] In other words, it may be possible to increase the strength and rigidity of the bulge portion 124 to a desired level even if the thickness of the low-angle inner spiral layer portion 126a including the high-strength low-angle inner spiral layer 126aa is more than about 30% of the total thickness of the bulge portion 124. In other words, the strength and rigidity of the bulge portion 124 can be increased to a desired level even if the high-strength low-angle inner spiral layer 126aa is arranged in a region exceeding about 30% of the total thickness of the bulge portion 124. When the thickness of the low-angle inner spiral layer portion 126a is more than aboutHowever, since the thickness of the bulge portion 124 is 30% of the total thickness of the bulge portion 124, the effect of reinforcing the bulge portion 124 cannot be improved in terms of the use amount of the fiber-reinforced plastic and the material cost.

[0045] The strength of the bulge portion 124 may be structurally increased toward a portion closer to the metal boss 112, and consequently, the strength of the low-angle inner spiral layer portion 126a may also be increased. Furthermore, as shown in Fig. 5, a transition region 128, which is a portion where the annular layer 122a of the cylindrical portion 122 ends, may be arranged between the bulge portion 124 and the cylindrical portion 122. The cylindrical portion 122, which is the straight portion of the support layer 120, and the bulge portion 124, which is the curved portion, are connected to each other at the transition portion 128.

[0046] To monitor the effect of increasing the burst pressure (e.g., burst strength) of the high-pressure tank when strengthening the strength and rigidity of the bulge portion according to the present disclosure, a high-pressure tank (Comparative Example 1) in which the bulge portion of the support layer is manufactured using a single fiber-reinforced plastic, and high-pressure tanks (Examples 1 and 2) in which the bulge portion of the support layer is manufactured using heterogeneous fiber-reinforced plastics were prepared. Furthermore, the burst pressure of the high-pressure tank according to Comparative Example 1 and the burst pressure of the high-pressure tanks according to Examples 1 and 2 were measured. The measurement results are shown in Table 1 below.

[0047] Specifically, the high-pressure tanks of Examples 1 and 2 and the high-pressure tank of Comparative Example 1 were manufactured under the same conditions, except that the bulge portion of the support layer of the high-pressure tank of Comparative Example 1 was formed using a low-strength fiber-reinforced plastic having a strength of 2,550 MPa and a rigidity of 135 GPa. The bulge portions of the support layers of the high-pressure tanks of Examples 1 and 2 were formed by blending and using a high-strength fiber-reinforced plastic having a strength of 3,040 MPa and a rigidity of 159 GPa and a low-strength fiber-reinforced plastic having a strength of 2,550 MPa and a rigidity of 135 GPa.

[0048] However, the high-pressure tank according to Example 1 was manufactured using the high-strength fiber-reinforced plastic for a thickness range corresponding to 5% of the total thickness of the bulge section and adjacent to the lining layer. The low-strength fiber-reinforced plastic is used for the remaining thickness range corresponding to 95% of the total thickness of the bulge section. The high-pressure tank according to Example 2 was manufactured using the high-strength fiber-reinforced plastic for the highest layer (e.g., outermost layer) in a thickness range corresponding to 30% of the total thickness of the bulge section and adjacent to the lining layer. The low-strength fiber-reinforced plastic is used for the remaining thickness range corresponding to 70% of the total thickness of the bulge section. Table 1 Burst pressure Comparison example 1 1,00 Example 1 1,03 Example 2 1,04

[0049] As shown in Table 1, the high-pressure tanks of Examples 1 and 2 exhibit a higher burst pressure than the high-pressure tank of Comparative Example 1. Therefore, by manufacturing a high-pressure tank having a burst pressure at the same level as that of Comparative Example 1, it is possible to reduce the usage amount of the fiber-reinforced plastic, reduce the weight of the high-pressure tank, and increase the hydrogen-to-weight efficiency compared to Comparative Example 1. The burst pressure of Examples 1 and 2 is determined based on the value of Comparative Example 1.

[0050] Furthermore, Fig. 7 shows a burst pressure of the high-pressure tank with respect to positions of the low-angle inner spiral layers with a high strength formed by winding the fiber-reinforced plastic with a high strength. Fig.Figure 8 illustrates the burst pressure of the high-pressure tank with respect to the strength range of the bulge portion where the low-angle, high-strength inner spiral layers are used. The respective burst pressure values ​​are determined based on the burst pressure values ​​when no high-strength fiber-reinforced plastic is used.

[0051] In relation to Fig.7, the burst pressure of the high-pressure tank varies depending on the position of the low-angle, high-strength inner spiral layer formed as a single layer by winding the high-strength fiber-reinforced plastic once based on the thickness of the bulge portion. Specifically, the burst pressure is increased when the low-angle, high-strength inner spiral layer is positioned as any layer within a thickness range approximately 5 to 30% of the bulge portion thickness. The burst pressure is significantly increased when the low-angle, high-strength inner spiral layer is positioned as any layer within a thickness range approximately 15 to 25% of the bulge portion thickness.

[0052] In relation to Fig.8, when the low-angle inner spiral layer with high strength is formed by entirely winding the fiber-reinforced plastic with high strength in a thickness range corresponding to approximately 0% to 30% of the thickness of the bulge portion, the burst pressure of the high-pressure tank is increased compared to when no fiber-reinforced plastic with high strength is used and the fiber-reinforced plastic with high strength is wound in a different thickness range.

[0053] While the burst pressure of the high-pressure tank was approximately 1.00 when the bulge portion was formed using the low-strength fiber-reinforced plastic without using the high-strength fiber-reinforced plastic, the burst pressure of the high-pressure tank was 1.11 when the high-strength fiber-reinforced plastic was wound in a thickness range corresponding to approximately 0% to 30% of the bulge portion thickness. The burst pressure of the high-pressure tank was 1.10 when the high-strength fiber-reinforced plastic was wound in a thickness range corresponding to approximately 31% to 100% of the bulge portion thickness.

[0054] When the high-strength fiber-reinforced plastic was used entirely for the thickness range corresponding to approximately 0% to 30% of the thickness of the bulge portion, as described above, the burst pressure of the high-pressure tank was increased compared to the case where the low-strength fiber-reinforced plastic was used without using the high-strength fiber-reinforced plastic. The higher burst pressure of the high-pressure tank can be obtained even when a minimal amount of the high-strength fiber-reinforced plastic was used compared to the case where the high-strength fiber-reinforced plastic was used entirely for the thickness range corresponding to approximately 31% to 100% of the thickness of the bulge portion.

[0055] Therefore, it can be seen that the effect of increasing the burst pressure of the high-pressure tank can be obtained by using the fiber-reinforced plastic having a high strength in a predetermined range of the bulge portion based on the strength of the bulge portion according to the present disclosure.

Claims

[1] High-pressure tank (100), comprising: a support layer defining an outer layer of the high-pressure tank (100) and including a cylinder portion (122) in a center thereof, wherein the cylinder portion (122) is formed to have a structure in which ring layers (122a) and spiral layers (122b) laminated on an outer surface of a liner layer (110) are alternately laminated, and wherein the annular layer (122a) disposed beneath the annular layers (122a) and the spiral layers (122b) is layered first to position the outer surface of the lining layer (110) in direct contact with the annular layer (122a); and Curved portions (124) formed on both sides of the cylinder portion (122), the curved portion (124) including a portion of a flat-angled inner spiral layer (126a) which is an inner layer and a portion of a flat-angled outer spiral layer (126b) which is an outer layer, wherein the flat-angle inner spiral layer portion (126a) includes a plurality of flat-angle inner spiral layers, and wherein at least one flat-angle inner spiral layer of the plurality of flat-angle inner spiral layers is a high-strength flat-angle inner spiral layer (126aa) having greater stiffness than the other flat-angle inner spiral layers, wherein the at least one low-angle inner spiral layer (126aa) is formed from a fiber-reinforced plastic having a relatively higher strength and stiffness than fiber-reinforced plastics of any other of the plurality of low-angle inner spiral layers of the portion of the low-angle inner spiral layer (126a) or each layer of the portion of the low-angle outer spiral layer (126b), and wherein the at least one low-angle inner spiral layer (126aa) having greater stiffness and strength than any other of the plurality of low-angle inner spiral layers is disposed as a layer within a thickness range corresponding to approximately 15 to 25% of the thickness of the dome portion, such that the at least one low-angle inner spiral layer (126aa) completely wraps the dome portions (124) in the thickness range. [2] The high-pressure tank (100) according to claim 1, wherein the low-angle inner spiral layer (126a) portion is formed into a thickness range corresponding to approximately 5% to 30% of a total thickness of each bulge portion. [3] High-pressure tank (100) according to claim 1, wherein the portion is formed from a low-angled outer spiral layer (126b) in a thickness range corresponding to approximately 70% to 95% of a total thickness of the bulge portions (124). [4] The high-pressure tank (100) of claim 1, wherein a portion of the plurality of low-angle inner spiral layers of the low-angle inner spiral layer portion (126a) are high-strength low-angle inner spiral layers (126aa) having a relatively high stiffness, and the remaining low-angle inner spiral layers are low-strength low-angle inner spiral layers (126ab) having a relatively low stiffness. [5] The high-pressure tank (100) of claim 4, wherein the low-angle inner spiral layers having a high strength (126aa) are arranged as inner layers of the low-angle inner spiral layer section, and wherein all the low-angle inner spiral layers having a low strength (126ab) are arranged as outer layers of the low-angle inner spiral layer section. [6] The high-pressure tank (100) of claim 4, wherein the low-angle inner spiral layers having a high strength (126aa) are arranged as outer layers of the low-angle inner spiral layer section, and wherein all the low-angle inner spiral layers having a low strength (126ab) are arranged as inner layers of the low-angle inner spiral layer section. [7] The high-pressure tank (100) according to claim 4, wherein the low-angle inner spiral layer with a high strength (126aa) and the low-angle inner spiral layer with a low strength (126ab) are arranged in a mixed pattern without limiting the order of stacking the layers. [8] The high-pressure tank (100) of claim 4, wherein the low-angle inner spiral layer having a high strength (126aa) and the low-angle inner spiral layer having a low strength (126ab) are arranged in an intermingled pattern in which the layers are alternately stacked on top of one another. [9] The high-pressure tank (100) according to claim 1, wherein the low-angle inner spiral layer portion (126a) is configured by the low-angle inner spiral layer having a high strength (126aa). [10] The high-pressure tank (100) according to claim 1, wherein the low-angle inner spiral layer having a high strength (126aa) is arranged as a lowermost layer of the low-angle inner spiral layer portion (126a). [11] A high-pressure tank (100) according to claim 1, wherein the bulge portions (124) are formed by winding a fiber-reinforced plastic around outer surfaces of a lining layer (110), and wherein a metal boss (112) is arranged at an acute angle within a predetermined range with respect to a direction of a central axis of the high-pressure tank (100).

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