Multilayer carbon fiber reinforced composite hydrogen storage cylinder and manufacturing method thereof

Abstract

The invention relates to a multilayer carbon fiber reinforced composite hydrogen storage cylinder and a manufacturing method thereof, and belongs to the technical field of hydrogen storage cylinders. The gas cylinder comprises an alloy bottle opening, a plastic lining layer, a rubber self-tightening layer, a carbon fiber woven layer and a carbon fiber winding layer which are sequentially arranged from inside to outside. The alloy bottle opening is manufactured through traditional machining. The plastic lining layer covers the surfaces of the alloy bottle opening and the inner container, is made of polytetrafluoroethylene or high-density polyethylene, and has excellent hydrogen corrosion resistance and gas barrier property; the rubber self-tightening layer covers the outside of the plastic lining layer, and the bottle opening area is properly thickened to enhance the structure; the carbon fiber woven layer is manufactured by adopting a dry three-dimensional weaving process, and is impregnated and cured by resin after being woven; and the carbon fiber winding layer covers the braid layer by adopting a wet winding process and is used as a main bearing layer. Through structural design and process optimization of the multi-layer composite material, the advantages of light weight, high strength, high corrosion resistance, fatigue resistance and the like of the gas cylinder are realized.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage cylinder manufacturing technology, specifically to a multi-layer composite material hydrogen storage cylinder suitable for high-pressure hydrogen storage and its manufacturing method. More specifically, this invention relates to a composite material cylinder structure with a plastic inner liner, a rubber self-tightening layer, and a double-layer carbon fiber reinforcement layer, aiming to improve the cylinder's lightweight level, local structural strength, and corrosion resistance, making it suitable for hydrogen fuel cell vehicles, aerospace, stationary hydrogen storage systems, and other fields. Background Technology

[0002] Hydrogen energy, as a highly efficient and clean secondary energy source, utilizes high-pressure gaseous hydrogen storage as the most mature and widely used hydrogen storage technology. Hydrogen storage cylinders, as key carriers in hydrogen energy storage and transportation, directly affect the safety, economy, and reliability of the system. Traditional high-pressure hydrogen storage cylinders are mainly divided into four types: Type I (all-metal), Type II (metal liner with circumferential fiber winding), Type III (metal liner with full winding), and Type IV (non-metal liner with full winding).

[0003] Current technology has several drawbacks: Due to their low hydrogen storage density, all-metal Type I cylinders and Type II cylinders with circumferentially wound metal liner have been largely phased out. Type III cylinders are heavy and prone to hydrogen embrittlement of the metal layer, while Type IV cylinders have poor rigidity in their plastic liner, resulting in insufficient safety and stability during manufacturing and service. The fiber layer forming methods for carbon fiber reinforced composite hydrogen storage cylinders mainly include wet winding, dry winding (prepreg winding), and weaving. Wet winding is low-cost and efficient, but has poor precision in controlling resin content and fiber distribution; dry winding has high precision and good performance, but is costly and complex; three-dimensional weaving technology can achieve fiber interweaving in three-dimensional space, giving the composite material higher interlaminar strength and damage tolerance, but it is less efficient and more expensive when used alone as a load-bearing layer.

[0004] Therefore, there is an urgent need in this field for an innovative method for designing and manufacturing gas cylinder structures that can comprehensively utilize the advantages of various materials and processes to achieve the best balance between gas cylinder performance, cost, and reliability. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multilayer composite material structure hydrogen storage cylinder and its manufacturing method. This cylinder, through a novel layered structure design and material combination, more effectively solves problems such as hydrogen embrittlement of the metal liner, interlayer electrochemical corrosion, weak interface bonding, and insufficient fatigue resistance. At the same time, it has the advantages of lightweight, high strength, and controllable process, meeting the stringent requirements of high-pressure hydrogen storage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A multi-layer composite hydrogen storage cylinder, characterized by comprising the following layers arranged coaxially from the inside out: an alloy cylinder neck 10: serving as the structural foundation of the cylinder and the base for forming the outer plastic, rubber, and fiber layers; a plastic inner liner 20: tightly bonded to the surface of the alloy cylinder neck in the cylinder neck area and the cylinder neck-end transition zone, forming a secondary barrier resistant to hydrogen corrosion and gas barrier; a rubber self-tightening layer 30: covering the plastic inner liner, providing elastic buffering, stress equalization, and sealing compensation; a carbon fiber braided layer 40: formed on the outside of the rubber self-tightening layer using a three-dimensional dry braiding process, reducing the thickness of the winding layer, mitigating fiber accumulation at the end cap, and providing excellent interlayer strength and impact resistance; and a carbon fiber winding layer 50: covering the outside of the carbon fiber braided layer using a wet winding process, serving as the main pressure-bearing layer of the cylinder.

[0007] Preferably, the alloy bottle neck 10 is made of titanium alloy, aluminum alloy or stainless steel; the alloy bottle neck 10 is an integrally formed structure, manufactured by machining (such as spinning, forging and then machining); The transition area 70 between the alloy bottle neck 10 and the bottle neck-end is designed with gradual thickening and rounded corners to reduce stress concentration. An circumferential anti-slip ring 11 is added to the end cap structure area of ​​the alloy bottle neck 10 to reduce the relative sliding between the alloy bottle neck 10 and the outer plastic inner liner layer 20. Preferably, the plastic liner 20 is made of polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE); the plastic liner has a uniform thickness and is tightly bonded to the alloy liner through injection molding, rotational molding, or extrusion coating processes. Preferably, the material used for the rubber self-tightening layer 30 is fluororubber (FKM) or ethylene propylene rubber (EPR); the thickness of the rubber self-tightening layer 30 is 0.8-1.2 mm (preferably 1 mm) in the bottle body area, continuously varies in the end cap area, and increases to 1.5-2.5 mm towards the bottle mouth area; the elastic properties of the rubber self-tightening layer 30 can absorb micro-strain during the filling and defilling process of the gas cylinder, reduce fretting wear between the fiber layer and the inner liner, and can apply beneficial prestress to the inner liner and fiber layer through its own expansion. Preferably, the carbon fiber braided layer 40 uses high-strength carbon fiber tow (12K or 24K) of T700, T800 or T1000 grade, and is dry-braided by a three-dimensional four-way or five-way braiding machine; the braiding angle is optimized according to the stress distribution to achieve a reasonable distribution of fibers in the axial, circumferential and radial directions. Preferably, the carbon fiber winding layer 50 uses carbon fiber of the same or similar grade as the braided layer 40, and is wound by a computer-controlled wet winding machine; the resin system is a fatigue-resistant and high-toughness epoxy resin; the winding adopts a combination of circumferential winding and longitudinal winding, and the winding angle and number of layers are precisely calculated and laid up according to the design pressure, diameter and aspect ratio of the gas cylinder. Compared with the prior art, the beneficial effects of the present invention are as follows: The inner lining layer 20 and the rubber self-tightening layer 30 isolate the metal and carbon fiber to avoid electrochemical corrosion. During the filling and discharging of hydrogen in the gas cylinder, the rubber self-tightening layer 30 applies self-tightening force to the inner plastic liner layer 20 and the wound fiber layer 40, buffering the micro-strain of the other two layers during rapid filling and discharging, so that the stress distribution is more uniform. Compared to Type III gas cylinders, this structure uses an alloy cylinder mouth + plastic liner, which significantly reduces the weight of the inner liner; The fiber braided layer 40 has good structural integrity and strong anti-delamination ability, providing a stable and reliable support base for the outer fiber winding layer 50. Meanwhile, the double-layer fiber-reinforced structure can further reduce weight through optimized design while ensuring strength. The overall lightweight effect is better than that of traditional Type III gas cylinders and close to that of Type IV gas cylinders. Attached Figure Description Figure 1 This is a longitudinal cross-sectional structural diagram of a multi-layer composite material hydrogen storage cylinder provided in an embodiment of the present invention. Figure 2 yes Figure 1 A magnified view of a portion of area A, highlighting the multi-layered structure near the bottle opening. Figure 3 yes Figure 2 A magnified view of a portion of area C, highlighting the structural features of the transition between the alloy bottle neck and the plastic liner at the end cap. Figure 4 This is a three-dimensional structural diagram of a multi-layer composite material hydrogen storage cylinder provided in an embodiment of the present invention. Figure 5 yes Figure 4 A magnified view of a portion of region B, highlighting the three-dimensional structure of the head area. Figure 6 This is a flowchart of the main process flow of the manufacturing method provided in the embodiments of the present invention. In the attached diagram: 10, alloy bottle neck; 11, alloy bottle neck anti-slip ring; 20, plastic inner liner; 30, rubber self-tightening layer; 40, carbon fiber woven layer; 50, carbon fiber winding layer; 60, bottle neck; 70, transition rounded corner area; 80, end cap area.

Claims

1. A multi-layered composite hydrogen storage cylinder, characterized in that, The components, arranged sequentially from the inside out, include: an alloy bottle neck; a plastic inner liner covering the alloy bottle neck and the inner liner surface; a rubber self-tightening layer covering the plastic inner liner; a carbon fiber braided layer made using a dry three-dimensional braiding process; and a carbon fiber winding layer covering the carbon fiber braided layer using a wet winding process.

2. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, The plastic inner liner is made of polytetrafluoroethylene or high-density polyethylene, has a uniform thickness, and is resistant to hydrogen corrosion and has gas barrier properties.

3. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, The material of the rubber self-tightening layer is fluororubber, butyl rubber or ethylene propylene rubber, with a thickness of 0.8-1.2 mm. The thickness varies continuously in the cylinder head area and is 1.5-2.5 mm at the cylinder mouth.

4. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, The carbon fiber braided layer uses T700, T800 or T1000 grade carbon fiber with a fiber specification of 12K or 24K. After weaving, it is impregnated and cured with modified epoxy resin.

5. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, The carbon fiber winding layer adopts a wet winding process, with the winding angle arranged alternately in the circumferential and longitudinal directions, and the number of winding layers is determined according to the design pressure.

6. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, The alloy bottle neck and the gas cylinder pressure reducing valve can be integrally formed, or a straight thread connection can be used.

7. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, At the interface between the alloy bottle neck and the plastic inner liner, a circumferential anti-slip ring is added.

8. The multi-layer composite structure hydrogen storage cylinder according to claim 1, characterized in that, The self-tightening rubber layer has a uniform thickness in the bottle body and end cap sections, and its thickness gradually increases in the rounded corner transition section to the bottle mouth section.

9. A method for manufacturing a multilayer composite hydrogen storage cylinder as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: The alloy bottle neck is manufactured using machining and then subjected to surface pretreatment; Step 2: Fabricate a plastic liner on the outer surface of the alloy bottle neck; Step 3: Mold a self-tightening rubber layer onto the outer plastic liner layer; Step 4: Perform three-dimensional dry weaving on the outside of the rubber self-tightening layer to form a carbon fiber braided layer, and then impregnate and cure it with resin; Step 5: Wet carbon fiber is wound around the carbon fiber braided layer to form a carbon fiber wound layer, and then cured.

10. The method according to claim 8, characterized in that, The molding method for the plastic inner liner in step two is injection molding or extrusion overmolding.

11. The method according to claim 8, characterized in that, In step four, the starting point of the three-dimensional weaving is located at one end of the bottle opening. During the weaving process, the fiber delivery rate, tension, and rotation speed are dynamically adjusted according to the cross-sectional radius of the gas cylinder.

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