High-pressure hydrogen storage bottle for mobile equipment

Abstract

The invention relates to a high-pressure hydrogen storage cylinder for mobile equipment, which comprises an airtight inner container and a carbon fiber winding layer, the carbon fiber winding layer is wound outside the airtight inner container, the cylinder body adopts an axisymmetric revolution body structure and consists of a cylinder mouth section seal head, a middle main body section and a cylinder navel end seal head, the cylinder mouth section seal head and the cylinder navel end seal head adopt ellipsoidal crown structures, and the middle main body section and the cylinder navel end seal head adopt ellipsoidal crown structures. And smooth transition design is adopted for the joints among the bottle opening section seal head, the middle main body section and the bottle navel end seal head. The carbon fiber winding layer is formed by compositing high-strength carbon fibers and a resin matrix and sequentially winding the high-strength carbon fibers and the resin matrix according to a certain angle, the carbon fiber winding layer is tightly combined with the airtight inner container into a whole after being cured and formed, and the carbon fiber winding direction angle is divided into a combination of the annular direction not passing through the end socket end and the spiral direction passing through the end socket end according to stress distribution and an opening of the gas cylinder; in order to ensure the strength and light weight, the winding angle can be adjusted and continuously changed according to the position no matter whether the winding is performed in the spiral direction or the annular direction. The pneumatic resistance is optimized, the space adaptability is high, and customization is convenient.

Description

Technical Field

[0001] This invention relates to the field of hydrogen energy storage technology, specifically to a high-pressure hydrogen storage cylinder for mobile equipment with stringent requirements for space, weight, and aerodynamic shape, and is particularly suitable for scenarios such as hydrogen fuel cell aircraft. Background Technology

[0002] Hydrogen fuel, as a highly promising new energy source in the global energy transition, has the core advantage of producing only water as a combustion product, achieving zero carbon emissions throughout its entire life cycle. This perfectly aligns with the urgent needs of transportation, aerospace, and other fields for green and low-carbon development, making it one of the key directions for solving the environmental pollution and resource depletion problems of traditional fossil fuels. However, the inherent physical properties of hydrogen energy pose a significant bottleneck to its large-scale commercial application. Specifically, gaseous hydrogen has an extremely low energy density, only about 12.7 kJ / L under standard atmospheric pressure and room temperature, far lower than traditional fuels such as gasoline (about 34.2 MJ / L) and diesel. This means that to meet the endurance requirements of equipment, it is necessary to increase the amount of hydrogen stored per unit volume or unit weight through specific technological means. Therefore, hydrogen storage technology has become the core key restricting the development of the hydrogen energy industry.

[0003] Currently, the mainstream hydrogen energy storage technologies worldwide are mainly divided into two categories: liquefaction storage and high-pressure gaseous storage. Liquefaction storage technology liquefies hydrogen by cooling it to an ultra-low temperature of -253°C, utilizing the high energy density of liquid hydrogen (approximately 10 MJ / L) for efficient storage. However, this technology has insurmountable shortcomings: on the one hand, maintaining the ultra-low temperature environment requires complex insulation systems and continuous refrigeration energy consumption, resulting in energy losses of up to 30%-40% during the liquefaction process, significantly increasing the total life cycle cost; on the other hand, liquid hydrogen is prone to evaporation loss during storage and transportation, which not only reduces storage efficiency but also imposes stringent safety requirements. Furthermore, it cannot be stored long-term without a cooling system, limiting its widespread application in mobile equipment. High-pressure gaseous storage has become the mainstream choice for mobile applications such as automobiles and aviation due to its high technological maturity and relatively controllable cost. This technology compresses hydrogen to a high pressure of 35MPa-70MPa and uses dedicated hydrogen storage cylinders for storage and transportation.

[0004] To balance the weight and pressure resistance of hydrogen storage cylinders, the industry generally adopts a carbon fiber wound composite structure. The inner liner is made of aluminum alloy or polymer material to provide airtightness, and the outer layer is wound with a composite material of high-strength carbon fiber and resin. This design can significantly improve the volume ratio (hydrogen storage volume per unit weight) of the hydrogen storage cylinder, meeting the basic requirements of lightweight mobile equipment.

[0005] Currently, the vast majority of automotive hydrogen storage cylinders adopt the classic structure of "cylindrical in the middle + hemispherical or semi-ellipsoidal end caps at both ends". This configuration can save space inside the vehicle, especially for the side-by-side placement of multiple hydrogen storage cylinders in heavy vehicles, and also facilitates mass production.

[0006] However, compared to automotive applications, hydrogen storage cylinders used in aviation or robotics face more complex technical challenges and constraints. For example, aviation equipment has more stringent requirements for weight-to-volume ratio. The payload of an aircraft directly affects its flight speed, range, and fuel economy. Therefore, aviation hydrogen storage cylinders need to be as lightweight as possible while meeting high-pressure resistance requirements. Secondly, the internal space of aviation equipment is extremely limited and must be adapted to the complex overall configuration of the fuselage, wings, etc. In particular, aircraft face complex mechanical environments such as aerodynamic drag, airflow disturbance, and vibration impact during takeoff, landing, and flight. The configuration of the hydrogen storage cylinder must simultaneously meet aerodynamic optimization requirements and stress balance requirements to avoid affecting flight safety due to local stress concentration. In conclusion, traditional hydrogen storage cylinder configurations and design concepts are no longer fully adapted to the specific needs of aviation scenarios, and there is significant room for optimization. The development of aviation hydrogen storage cylinders must move beyond traditional structural frameworks and incorporate systematic and targeted optimization designs that consider various factors such as specific flight parameters of the aircraft (e.g., cruise speed, maximum payload), range targets, overall configuration layout, aerodynamic design requirements, and mechanical environment characteristics. Only in this way can existing technological bottlenecks be overcome, laying the foundation for the large-scale application of hydrogen energy in the aviation field. Summary of the Invention

[0007] This invention aims to overcome the limitations of existing high-pressure hydrogen storage cylinder designs in adapting to mobile equipment with stringent requirements regarding space, weight, aerodynamic shape, and mechanical environment. Specifically, addressing the problems of low space utilization, poor system integration, impaired aerodynamic performance, or localized stress concentration caused by the difficulty in customizing designs based on the irregular installation space and external aerodynamic profile of existing equipment, this invention provides a high-pressure hydrogen storage cylinder for mobile equipment.

[0008] This invention proposes a high-pressure hydrogen storage cylinder for mobile equipment, which consists of an airtight inner liner, a carbon fiber winding layer, a bottle mouth, and a bottle navel. The carbon fiber winding layer is wound around the outside of the airtight inner liner. One side of the bottle body is the bottle mouth, and the other side is the bottle navel (or "bottom"). The high-pressure hydrogen storage cylinder adopts an axisymmetric gyroscopic structure. The bottle body is composed of three sections: the bottle mouth end cap, the middle main body section, and the bottle navel end cap. Both the bottle mouth end cap and the bottle navel end cap adopt an ellipsoidal crown structure. The middle main body section is a waist-shaped structure that is thin at both ends and thick in the middle. The connection between the bottle mouth end cap, the middle main body section, and the bottle navel end cap adopts a smooth transition design.

[0009] In this invention, the generatrix of the axisymmetric gyroscopic structure of the bottle body adopts a quadratic curve or an optimized smooth transition curve.

[0010] In this invention, the diameters at the connection points between the middle main body segment and the bottle mouth segment end cap and the bottle navel end cap can be unequal, giving the bottle a symmetrical appearance that is thicker at one end and thinner at the other.

[0011] In this invention, the ratio of the major and minor axes of the bottle neck end cap and the bottle navel end cap are not equal; that is, the surface area of ​​the bottle navel end cap with the smaller diameter is close to the surface area of ​​the bottle neck end cap with the larger diameter. This ensures strength requirements while reducing air resistance and increasing the density ratio.

[0012] In this invention, the radial radius of the bottle body gradually decreases continuously from the thickest part of the middle main body section to the apex of the bottle mouth section, the middle main body section, and the bottle navel end cap.

[0013] In this invention, the airtight inner liner is made of metal or polymer material, and the carbon fiber winding layer is a composite of high-strength carbon fiber and resin matrix, wound at a certain angle and in a certain order. After curing, the carbon fiber winding layer is tightly integrated with the airtight inner liner. The winding direction angle of the carbon fiber is divided into a combination of circumferential winding that does not pass the end cap and spiral winding that passes the end cap, depending on the stress distribution and the gas cylinder opening. In order to ensure strength and lightweight, the winding angle will be continuously adjusted and changed according to the position, regardless of whether it is spiral winding or circumferential winding.

[0014] In this invention, to further adapt to aerodynamic or shape matching requirements, the hydrogen storage cylinder can have an asymmetrical appearance that is thicker at the front and thinner at the back, achieving drag reduction. Specifically, this can be achieved by adjusting curve parameters to precisely match the spatial and aerodynamic layout of the aircraft, while ensuring uniform structural stress distribution and avoiding local stress concentration; a balance point is found between density ratio, aerodynamic characteristics, and shape features.

[0015] Similar to traditional vehicle-mounted hydrogen storage cylinders, this gas cylinder employs a double-layer composite structure. The inner layer is an airtight inner liner 11, and the outer layer is a carbon fiber wound reinforcement layer 12. The airtight inner liner 11 is made of metal or polymer material, effectively preventing hydrogen leakage and also serving as a mandrel for support during the outer winding process. The outer carbon fiber wound reinforcement layer 12 is composed of high-strength carbon fiber and a resin matrix, providing reliable pressure-resistant support for the gas cylinder. Similarly, to accommodate the asymmetrical configuration and stress distribution characteristics at both ends of the gas cylinder, the carbon fiber winding direction uses a combination of large-angle circumferential winding that does not pass through the end cap and spiral winding that does pass through the end cap. However, unlike traditional cylindrical hydrogen storage cylinders, because the radius of the middle section of the hydrogen storage cylinder continuously changes, the winding angle also varies with the radius during circumferential winding to ensure strength while achieving lightweighting. The spiral winding here should be interpreted broadly, including longitudinal winding that passes through the apex of the end cap on the navel side of the cylinder.

[0016] Finally, this invention can be applied to aircraft powered by hydrogen fuel cells, as well as aircraft powered by hydrogen-fired thermal engines. Therefore, its shape is more streamlined, allowing it to conform to the overall shape of the aircraft and be installed in wing pods, engine compartments, fuselage interiors, etc. Similarly, this invention can also be used in scenarios with specific aerodynamic and spatial requirements, such as robotics and supercars.

[0017] The beneficial effects of this invention are as follows: 1. Optimized Aerodynamic Drag: The smooth-transition three-section structure, asymmetrical appearance design, and streamlined gyratory generatrix allow the gas cylinder to be perfectly integrated into the aerodynamic layout of high-speed vehicles such as aircraft, reducing the drag coefficient. 2. Strong Space Adaptability: The asymmetrical configuration and customized gyratory generatrix design can be flexibly adjusted according to the vehicle's geometry, such as the internal space shape of the aircraft fuselage and wings, avoiding wasted space. 3. Significantly improved density ratio: The combination of the waist-drum shaped middle main body section and the differentiated end cap design effectively increases the hydrogen storage volume, improves the density ratio, and extends the driving range and working time under the same surface area, weight and length. 4. Convenient customization: It can be customized according to different load requirements and cost budgets, and is suitable for hydrogen fuel storage needs of various equipment such as helicopters, drones, small passenger planes, robots, and supercars. The principle of this invention is as follows: This invention deeply integrates configuration optimization and structural reinforcement to achieve synergistic optimization of density ratio, space adaptability and aerodynamic performance; at the same time, it adopts multi-directional variable angle carbon fiber winding technology to enhance pressure resistance on the basis of lightweighting.

[0018] The aforementioned technical features work together to form an integrated "configuration-process" solution, ultimately achieving a comprehensive breakthrough in the density ratio, aerodynamic resistance, structural strength, and spatial adaptability of gas storage cylinders, providing key technical support for the research and development of hydrogen-powered mobile equipment. Attached Figure Description

[0019] Figure 1 A cross-sectional view of the present invention.

[0020] Figure 2 An airtight inner liner 11 with an outer shape formed by splicing together three ellipsoidal arcs, wherein the outer shapes of the three ellipsoids are represented by different line types, and the thickened part is the part used in the inner liner in this embodiment.

[0021] Figure 3 Specific embodiments of variable-angle circumferential winding.

[0022] Figure 4Specific embodiments of variable angle spiral winding.

[0023] Figure 5 This invention is illustrated in the installation location on an aircraft.

[0024] In the diagram, the following labels are used: 2 is the fuselage section, 3 is the wing and engine nacelle, 11 is the airtight inner liner, 12 is the carbon fiber winding layer, 13 is the bottle neck, 14 is the bottle neck section end cap, 16 is the middle main body section, 15 is the bottle navel end cap, 21 is the forward section of the fuselage, 121 is the circumferentially wound fiber, 122 is the carbon fiber filament, 17 is the bottle navel, and 100 is the overall structure. Detailed Implementation Example 1

[0025] According to the present invention, a specific embodiment of an aviation hydrogen storage cylinder is provided for illustration.

[0026] The hydrogen storage cylinder is symmetrical about its central axis, with an inner liner made of aluminum alloy and an outer layer of carbon fiber. The opening is made of metal. Its cross-sectional structure is as follows: Figure 1 As shown, it includes an airtight inner liner 11, a carbon fiber winding layer 12, and a bottle neck 13. The bottle neck 13 is made of metal and, starting from the bottle neck 13, along the axis of symmetry, can be roughly divided into an ellipsoidal cap-shaped bottle neck end cap 14, a drum-shaped middle main body section 16, and an ellipsoidal cap-shaped bottle navel end cap 15. Among them, as... Figure 2 As shown, both the cap and the inner liner of the middle section are part of an ellipsoid. The three ellipsoids are tangent at the junction, and therefore have the same radius and slope at the junction. Secondly, the distance from the largest diameter point of the middle main body section 16 to the bottle mouth 13 is not equal to its distance to the bottle navel 17. The ratio of the major and minor axes of the ellipsoids corresponding to the bottle mouth end cap 14 and the bottle navel end cap 15 are different. Although both are oblate ellipsoids, the bottle navel end cap 15 is closer to a perfect sphere. Therefore, the overall shape presents a streamlined feature of being "thicker at one end and thinner at the other".

[0027] Then, after the carbon fiber bundles are impregnated with epoxy resin, they are orderly wrapped onto the surface of the airtight inner liner at a preset angle and with a certain tension, according to the hydrogen storage cylinder's structure and stress requirements, using a winding machine. Because the radius of curvature varies throughout the hydrogen storage cylinder, the tension on the carbon fiber winding layer 12 varies at different locations during inflation. The strength of the carbon fiber winding layer 12 is ensured by adjusting the angle according to the magnitude and direction of the force. In this embodiment, because the central main body section 16 of the hydrogen storage cylinder exhibits a central drum-like geometric feature, variable winding angle reinforcement is also required. Figure 3 The large-angle circumferential winding shown, which does not pass through the end cap, is also circumferential winding, with the winding angle of the central main section 16 being greater than that of the sides; or in other words, the spacing of the carbon fiber bundles 121 is smaller than that of the sides. Similarly, for longitudinal winding, due to the presence of the bottle opening, a variable angle technique is required. Figure 4The spiral winding combination shown is such that the carbon fiber filament 122 covers the entire end of the bottle navel without affecting the bottle mouth 13.

[0028] Finally, the different ratios of the major and minor axes of the two end caps result in similar surface areas for the bottle neck end cap 14 and the bottle navel end cap 15. This means that during carbon fiber winding, only the helical and longitudinally wound filaments cover both ends, ensuring that the winding thickness of the bottle navel end cap 15 is not excessive, thus increasing the effective hydrogen storage volume without adding weight. Finally, the wound preform is placed in a curing furnace to allow the resin to fully cross-link and cure, forming a dense carbon fiber resin composite reinforcement layer, ultimately resulting in a hydrogen storage bottle structure that combines high strength and lightweight.

[0029] Taking this embodiment without an external fairing and bottle mouth seal as an example, when the bottle mouth faces the wind, the incoming flow velocity is 50-500 km / h, and the maximum diameter is 0.5 m, compared with the traditional hydrogen storage cylinder with hemispherical heads at both ends and a cylindrical section in the middle, the present invention exhibits significant spatial and aerodynamic advantages. While maintaining the same surface area and total length, calculations show that the hydrogen storage capacity of the present invention can increase by 21%, and the windward area decreases by 20%. Numerical simulation results show that the drag coefficient decreases by 11%-17%, and the combined effect results in an overall drag reduction of 17%-21%. If the windward area and volume are maintained, although the surface area increases by 7.5%, the volume of the present invention can increase the hydrogen storage capacity by 30% and reduce the overall drag by 12%-16%.

[0030] like Figure 5 As shown, this invention can be installed inside the fuselage 2 or engine nacelle 3 of an aircraft, conforming to the aerodynamic shape of the aircraft to reduce air resistance while increasing space utilization, thus achieving weight and drag reduction. It can also be designed with a symmetrical front-to-back shape, or even be fitted to the front section 21 of the fuselage with a tapered front and thicker rear. Of course, it is not limited to this. Figure 5 As shown, the present invention can also be installed in components such as pods, hangars, and eVTOL engine cantilever arms of aircraft. In addition, the configuration concept based on customized design of space and aerodynamic shape can also be extended to other high-end mobile equipment with stringent requirements for space layout, lightweighting and shape, such as high-speed ground vehicles and special robots.

[0031] It should be clarified that the technical solutions disclosed in this invention are not limited to the specific forms and details described in the above specific embodiments. The above embodiments are merely illustrative examples of the technical solutions of this invention, used to clearly and intuitively illustrate the core concept and implementation methods of this invention, and are not intended to limit the scope of protection of this invention. Any person skilled in the art, after understanding the technical purpose and core technical concept of this invention, can make various modifications, adjustments, substitutions, and technical variations to the above specific embodiments without departing from the purpose and scope of protection defined by the claims. All such reasonable technical variations should fall within the scope of protection of this invention.

[0032] Specifically, the installation methods, winding angles, and material selection details mentioned in the above embodiments can all be reasonably adjusted technically and do not constitute a limitation of the present invention. For example, in practical applications, the length-to-width ratio and placement position of the front and rear ends can be flexibly adjusted according to the overall configuration, size, internal space layout, flight performance, airworthiness compliance, and other actual conditions of the aircraft. Furthermore, the above embodiments show the use of analytical equations to describe the geometric shape of the middle section of the hydrogen storage cylinder; this can also be replaced by segmentation, interpolation, series expansion, etc. Moreover, the above embodiments show a Type IV bottle with a polymer composite material liner; this can also be replaced with a Type III bottle with a metal liner, both of which fall within the scope of protection of the present invention.

[0033] In summary, the scope of protection of this invention should be determined by the appended claims, and not by the description of the specific embodiments above. Any technical solutions that are equivalent or similar to the technical solutions defined in the claims of this invention, made by those skilled in the art under the guidance of the technical teachings of this invention, fall within the scope of protection of this invention.

Claims

1. A high-pressure hydrogen storage cylinder for mobile equipment, characterized in that... It consists of an airtight inner liner, a carbon fiber winding layer, a bottle mouth, and a bottle navel. The carbon fiber winding layer is wrapped around the outside of the airtight inner liner. The bottle mouth is on one side of the bottle body, and the bottle navel is on the other side. The high-pressure hydrogen storage bottle adopts an axisymmetric gyroscopic structure. The bottle body is composed of three sections: the bottle mouth end cap, the middle main body section, and the bottle navel end cap. Both the bottle mouth end cap and the bottle navel end cap adopt an ellipsoidal crown structure. The middle main body section is a waist-shaped structure that is thin at both ends and thick in the middle. The connection between the bottle mouth end cap, the middle main body section, and the bottle navel end cap adopts a smooth transition design.

2. A high-pressure hydrogen storage cylinder for mobile equipment according to claim 1, characterized in that... The generatrix of the axisymmetric gyroscopic structure of the bottle adopts a quadratic curve or an optimized smooth transition curve.

3. A high-pressure hydrogen storage cylinder for mobile equipment according to claim 1, characterized in that... The diameters at the connection points between the middle main body section and the bottle mouth section end cap and the bottle navel end cap can be unequal, giving the bottle a symmetrical appearance that is thicker at one end and thinner at the other.

4. A high-pressure hydrogen storage cylinder for mobile equipment according to claim 1, characterized in that... The ratio of the major and minor axes of the bottle neck end cap and the bottle navel end cap are not equal; that is, the surface area of ​​the bottle navel end cap with the smaller diameter is close to the surface area of ​​the bottle neck end cap with the larger diameter. This design ensures strength requirements while reducing air resistance and increasing the density ratio.

5. A high-pressure hydrogen storage cylinder for mobile equipment according to claim 1, characterized in that... The radial radius of the bottle body gradually decreases continuously from the thickest part of the middle main body section to the apex of the bottle mouth section, the middle main body section, and the bottle navel end cap.

6. A high-pressure hydrogen storage cylinder for mobile equipment according to claim 1, characterized in that... The airtight inner liner is made of metal or polymer material. The carbon fiber winding layer is a composite of high-strength carbon fiber and resin matrix, wound at a certain angle and in a certain order. After curing, the carbon fiber winding layer is tightly integrated with the airtight inner liner. The winding direction angle of the carbon fiber is divided into a combination of circumferential winding that does not pass the end cap and spiral winding that passes the end cap, depending on the stress distribution and the gas cylinder opening. In order to ensure strength and light weight, the winding angle will be continuously adjusted and changed according to the position, regardless of whether it is spiral winding or circumferential winding.

Images