Manufacturing method of regenerated carbon fiber reinforced lining and composite material pressure vessel

Abstract

The invention relates to the technical field of hydrogen storage high-pressure containers, and discloses a manufacturing method of a regenerated carbon fiber reinforced lining, which comprises the following steps: S1, manufacturing a pressure container inner container seal head according to a seal head mold, manufacturing by adopting an injection molding process, embedding a metal bottleneck valve seat into the seal head mold, and controlling the temperature of an injection molding material to be 200-300 DEG C and the temperature of the mold to be 70-80 DEG C; the invention further discloses a composite material pressure container with the regenerated carbon fiber reinforced lining, the composite material pressure container comprises the recoverable lining, the recoverable lining comprises an end socket and a cylinder body, and the end socket and the cylinder body are connected into a whole through welding; and the two metal bottleneck valve seats are respectively connected with the sealing heads at the two ends of the recyclable lining and are used for connecting an external pipeline of the pressure container. By recycling nylon 6 or nylon 66 and carbon fiber prepreg to manufacture the cylinder body and combining reelpipe forming and optimized carbon fiber winding design, the strength and the pressure bearing capacity of the inner container are improved, material use is reduced, and the problem of mass increase caused by a high-density metal reinforcing piece is solved through a light-weight structure.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen storage high-pressure containers, and in particular to a method for manufacturing a recycled carbon fiber reinforced liner and a composite material pressure container. Background Art

[0002] Composite gas cylinders are widely used in aerospace, new energy vehicles and other fields as energy storage devices due to their high strength, light weight and high gas storage density. The inner liner of a traditional Type IV hydrogen storage cylinder is usually made of plastic. Although it has good corrosion resistance and air tightness, its strength is relatively low. Under the external pressure of the carbon fiber winding layer, the inner liner may experience structural deformation, such as collapse, warping, and separation from the fiber layer. This phenomenon is called external pressure instability. This instability phenomenon will affect the safety of the hydrogen storage cylinder and even cause hydrogen leakage or equipment damage.

[0003] After searching, it is found that in the prior art, for example, the patent with Chinese authorization announcement number CN117489969B proposes an improved design, in which a reinforcement is embedded in the inner liner of the gas cylinder, and is integrally formed with the inner liner by rotational molding. This design improves the strength of the inner liner by adding reinforcements, thereby reducing the possibility of collapse or warping of the inner liner under external pressure. At the same time, this structure can improve the bonding performance between the inner liner and the fiber layer to a certain extent, avoid separation of the inner liner from the winding layer, and improve the overall stability and safety of the gas cylinder. However, since the embedding of reinforcements requires more complex processing technology and additional structural design, it may increase manufacturing costs and have a certain impact on the lightweight design of the inner liner.

[0004] Although the above technologies have solved certain external pressure instability problems, there is still room for further improvement in terms of lightweight, high strength and manufacturing process optimization of the liner. In particular, how to effectively reduce weight and reduce costs while ensuring the strength of the cylinder liner is still a technical challenge that needs to be overcome in related fields. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a method for manufacturing a recycled carbon fiber reinforced liner and a composite pressure vessel, which solves the problems of external pressure instability, fiber waste and weight increase caused by insufficient strength of the inner liner of a traditional composite gas cylinder.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for making a recycled carbon fiber reinforced lining, comprising the following steps:

[0007] S1. According to the head mold, the pressure vessel liner head is manufactured by injection molding process. The metal bottle mouth valve seat is embedded in the head mold. The injection material temperature is 200℃~300℃, the mold temperature is 70℃~80℃, and the injection pressure is 50MPa~150MPa;

[0008] S2. Making the inner shell of the pressure vessel by using a tube rolling process;

[0009] S3. The head and the cylinder are combined by ultrasonic welding technology, the welding frequency is 15kHz~20kHz, the transducer amplitude is 15μm~20μm, and the welding time is 0.5s~1.5s;

[0010] S4. Design the carbon fiber wrapped outer reinforcement layer according to the minimum blasting strength, the tension of a single fiber bundle is 15N~20N, and the thickness of a single layer is 0.2mm~0.3mm;

[0011] S5. Curing the pressure vessel after wet winding.

[0012] Preferably, in step S1, the head material is recycled nylon 6 or recycled nylon 66 and chopped fibers, and the processing method of the metal bottle mouth valve seat in step S1 is not limited to molding or spinning.

[0013] Preferably, in step 2, the barrel material is selected from nylon plus prepreg or nylon plus chopped fibers, wherein nylon is divided into recycled nylon 6 or recycled nylon 66, and can be made by the following method:

[0014] Made of recycled nylon 6 or recycled nylon 66 and carbon fiber prepreg, it is made through the tube rolling process;

[0015] Or it can be made of recycled nylon 6 or recycled nylon 66 and chopped fibers through injection molding process.

[0016] Preferably, the design of the carbon fiber wound outer reinforcement layer in step 4 is based on thin film theory calculation, and the winding ply angle range is determined to be 10° to 90° through grid theory.

[0017] Preferably, the curing step in step S5 includes:

[0018] The temperature rises to 70-80°C and the curing time is 1.5-2.5h;

[0019] The temperature rises to 100-120°C and the curing time is 5-7 hours.

[0020] Preferably, the epoxy resin in step S5 is a tough epoxy resin resistant to medium and high temperatures.

[0021] A composite pressure vessel with a recycled carbon fiber reinforced liner, comprising:

[0022] A recyclable liner, the recyclable liner comprising a head and a cylinder, which are connected into one by welding;

[0023] Two metal bottle mouth valve seats, which are respectively connected to the end caps at both ends of the recyclable liner and are used to connect the external pipeline of the pressure vessel;

[0024] A sealing ring, which is arranged at the joint of the metal bottle mouth valve seat and the recyclable liner head;

[0025] A carbon fiber wound outer reinforcement layer, which is wound around the outside of the recyclable liner to provide enhanced strength;

[0026] A glass fiber outer protective layer covering the outside of the carbon fiber wound outer reinforcement layer to provide external protection

[0027] Preferably, the metal bottle mouth valve seat is made of aluminum alloy 6061.

[0028] The invention provides a method for manufacturing a recycled carbon fiber reinforced liner and a composite material pressure vessel.

[0029] It has the following beneficial effects:

[0030] 1. The present invention achieves the technical effect of significantly reducing production costs by adopting a technical solution combining recycled nylon 6, recycled nylon 66 and chopped fibers, combined with mechanical recycling and injection molding processes. Compared with the production solution that only relies on new raw materials in the prior art, the present invention effectively utilizes recycled materials, reduces dependence on new raw materials, and reduces raw material procurement costs. At the same time, the recycling of thermoplastic resins reduces the generation and treatment costs of waste materials and optimizes resource utilization efficiency. Through the reasonable design and optimization of the winding layer angle, the material strength and structural stability are guaranteed, and the performance unevenness or waste caused by excessive reliance on new materials is avoided, thereby further reducing the overall production cost. In addition, the efficient injection molding and winding processes adopted by the present invention greatly improve production efficiency, shorten the production cycle, and reduce processing energy consumption.

[0031] 2. The present invention accurately optimizes the layup design of the carbon fiber wound outer reinforcement layer through thin film theory and grid theory, determines the winding angle, and controls the single layer thickness and single fiber bundle tension, so that the distribution of the reinforcement layer is more uniform and reasonable. Compared with the problems of high difficulty in reinforcement design and difficulty in accurately controlling the fiber force in the prior art, the present invention significantly improves the design efficiency of the winding layer, ensures the reliability and consistency of the reinforcement, and further improves the controllability of the production process. In addition, this design scheme can effectively solve the problem that the filling and holding pressure values ​​of the Type IV bottle need to be determined through complex calculations before winding, and avoids the occurrence of bottle instability (such as bottle collapse) due to excessive tension, thereby improving the overall stability and safety of the product.

[0032] 3. The present invention uses recyclable nylon and chopped fibers to make the head and the cylinder, and combines a lightweight carbon fiber reinforcement layer and a glass fiber outer protective layer to achieve an overall lightweight design of the composite pressure vessel. Unlike the design in the prior art that generally uses high-density metals such as stainless steel or aluminum alloy as reinforcements, the present invention effectively avoids the problem of increased overall mass of the liner due to excessive material density, while improving the portability and applicability of the container, making it suitable for a wider range of usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the structure of the recyclable inner liner of the present invention;

[0034] Figure 2 It is a cross-sectional view of the recyclable liner composite pressure vessel of the present invention;

[0035] Figure 3 The present invention is a flowchart of the method for making.

[0036] Among them, 1. Recyclable lining; 2. Metal bottle mouth valve seat; 3. Sealing ring; 4. Carbon fiber wrapped outer reinforcement layer; 5. Glass fiber outer protective layer. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Please refer to the attached Figure 1 The embodiment of the present invention provides a composite pressure vessel with a recycled carbon fiber reinforced liner, comprising the following steps:

[0039] S1. According to the head mold, the pressure vessel liner head is manufactured by injection molding process. The metal bottle mouth valve seat 2 is embedded in the head mold. The injection material temperature is 200℃~300℃, the mold temperature is 70℃~80℃, and the injection pressure is 50MPa~150MPa;

[0040] S2. Making the inner shell of the pressure vessel by using a tube rolling process;

[0041] S3. The head and the cylinder are combined by ultrasonic welding technology, the welding frequency is 15kHz~20kHz, the transducer amplitude is 15μm~20μm, and the welding time is 0.5s~1.5s;

[0042] S4. Design the carbon fiber wrapped outer reinforcement layer 4 according to the minimum blasting strength, the tension of a single fiber bundle is 15N to 20N, and the thickness of a single layer is 0.2mm to 0.3mm;

[0043] S5. Curing the pressure vessel after wet winding.

[0044] In step S1, the head material is recycled nylon 6 or recycled nylon 66 and chopped fibers. In step S1, the processing method of the metal bottle mouth valve seat 2 is not limited to molding or spinning.

[0045] In step 2, the barrel material is nylon plus prepreg or nylon plus chopped fibers, wherein nylon is divided into recycled nylon 6 or recycled nylon 66, and can be made by the following methods:

[0046] Made of recycled nylon 6 or recycled nylon 66 and carbon fiber prepreg, it is made through the tube rolling process;

[0047] Or it can be made of recycled nylon 6 or recycled nylon 66 and chopped fibers through injection molding process.

[0048] The design of the carbon fiber wound outer reinforcement layer 4 in step 4 is based on thin film theory calculation, and the winding ply angle range is determined to be 10° to 90° through grid theory.

[0049] The design of the carbon fiber winding outer reinforcement layer is based on the thin film theory. By calculating the stress distribution of the container liner under internal pressure, the minimum thickness and strength requirements of the carbon fiber winding layer are determined. The specific method is as follows:

[0050] Thin film theory calculations:

[0051] According to the geometric parameters (diameter and length) and internal pressure (design pressure) of the liner, using the film theory formula:

[0052]

[0053] Among them, σ is the material stress, P is the design pressure inside the container, r is the inner diameter of the container, and t is the thickness of the winding layer.

[0054] The strength value required by the winding layer is calculated and used for subsequent layer design.

[0055] Grid Theory Optimization:

[0056] Based on the grid theory and the characteristics of film stress distribution, the angle range of the winding layer is determined to be 10° to 90°, which is mainly divided into the following layer angles:

[0057] ±10°~30°: Provide circumferential reinforcement to withstand the main stress of the container internal pressure;

[0058] ±45°~60°: Provide shear enhancement and improve the bonding performance between the liner and the winding layer;

[0059] ±75°~90°: Provides axial reinforcement and improves overall structural stability.

[0060] Winding process implementation

[0061] Materials preparation:

[0062] Using high-strength carbon fiber prepreg, the tension of a single fiber bundle is set within the range of 15N to 20N;

[0063] The single layer thickness is controlled to be 0.2mm~0.3mm.

[0064] Winding equipment and parameters:

[0065] Use CNC filament winding equipment and set the winding speed to 50-70 m / min;

[0066] Low-angle (10°~30°), medium-angle (45°~60°) and high-angle (75°~90°) laying are carried out in sequence to ensure that the stress of the reinforcement layer is evenly distributed in all directions.

[0067] Multi-layer winding:

[0068] According to the calculation results, the total winding layer thickness is determined to be 14 to 18 mm;

[0069] After each layer is completed, the tension is adjusted to ensure that the fibers are arranged tightly without lint or looseness.

[0070] Enhancement layer inspection:

[0071] After winding is completed, ultrasonic non-destructive testing is used to check whether there are gaps, delamination or uneven defects in the winding layer.

[0072] Through the layering scheme designed by thin film theory calculation and grid theory, the carbon fiber reinforcement layer forms multi-directional reinforcement when the inner liner is under pressure, which not only improves the pressure bearing capacity, but also ensures the reasonable utilization rate of the fiber and avoids fiber waste. At the same time, the combination of different layering angles effectively improves the structural stability of the winding layer and avoids the separation or local failure of the fiber layer and the inner liner.

[0073] The S5 step curing step includes:

[0074] The temperature rises to 70-80°C and the curing time is 1.5-2.5h;

[0075] The temperature rises to 100-120°C and the curing time is 5-7 hours.

[0076] The epoxy resin in step S5 is a tough epoxy resin resistant to medium and high temperatures.

[0077] Please see attached Figure 2 and attached Figure 3 , a composite pressure vessel with recycled carbon fiber reinforced liner, comprising:

[0078] A recyclable liner 1, comprising a head and a cylinder, which are connected into one by welding;

[0079] Two metal bottle mouth valve seats 2, which are respectively connected to the ends of the recyclable liner 1 and are used to connect the external pipeline of the pressure vessel;

[0080] A sealing ring 3 is provided at the joint between the metal bottle mouth valve seat 2 and the seal head of the recyclable liner 1;

[0081] A carbon fiber wound outer reinforcement layer 4, which is wound outside the recyclable liner 1, is used to provide enhanced strength;

[0082] The glass fiber outer protective layer 5 covers the outer side of the carbon fiber wound outer reinforcement layer 4 to provide external protection.

[0083] The metal bottle mouth valve seat 2 is made of 6061 aluminum alloy.

[0084] The recyclable liner 1 is composed of a head and a cylinder. They are connected into a whole by welding technology, which not only ensures the integration of the structure but also enhances the internal sealing. The welded liner is the basis for the container to withstand the internal pressure.

[0085] The metal bottle mouth valve seat 2 is set at the two end caps of the liner. It is responsible for connecting the pressure vessel with the external pipeline, and at the same time, through the cooperation with the liner cap, a high-strength joint is formed. The metal bottle mouth valve seat 2 is processed by aluminum alloy 6061, so that it has high corrosion resistance and mechanical strength, meeting the use requirements in high-pressure environments.

[0086] At the connection part, the sealing ring 3 prevents the internal gas or liquid from leaking.

[0087] The carbon fiber wound outer reinforcement layer 4 is mainly used to withstand the stress generated by the high pressure inside the container. Through the winding of carbon fiber, the lining structure is significantly strengthened. Not only the overall strength is improved, but also the weight of the container is effectively reduced, making it easier to use and transport.

[0088] The outermost layer is a glass fiber outer protective layer 5 to protect the reinforcement layer from the external environment, such as physical wear and chemical corrosion. At the same time, glass fiber has good impact resistance, further improving the overall reliability of the container.

[0089] Example 1: Composite pressure vessel using carbon fiber prepreg to prepare pressure vessel liner

[0090] Preparation of pressure vessel liner head:

[0091] Material selection: The head material is made of recycled nylon 6 and chopped fibers, mixed in a mass ratio of 70:30.

[0092] Process parameters:

[0093] The mixed material was added into the injection molding machine, and the injection material temperature was set to 250°C, the mold temperature to 75°C, and the injection pressure to 100 MPa.

[0094] The holding time is 20s and the cooling time is 60s.

[0095] Production steps:

[0096] The aluminum alloy 6061 metal bottle mouth valve seat is processed by spinning and then embedded in the head mold;

[0097] After the injection molding is completed, the mold is demoulded to obtain the head.

[0098] Preparation of pressure vessel liner cylinder:

[0099] Material selection: The barrel material is made of recycled nylon 6 and carbon fiber prepreg, with a mass ratio of 90:10.

[0100] Process parameters:

[0101] Through the tube-rolling process, the mixed material is evenly spread and rolled into a cylindrical structure;

[0102] The forming rate is controlled at 10m / min.

[0103] Welding head and cylinder:

[0104] Welding technology: ultrasonic welding technology is used.

[0105] The welding frequency is 20kHz;

[0106] The transducer amplitude is 20 μm;

[0107] The welding time is 1s.

[0108] Welding requirements: After welding, the surface is continuous without any unfused parts or holes.

[0109] Carbon fiber wound outer reinforcement:

[0110] Winding design basis: Based on film theory and grid theory, the layering scheme is: 8H+3s15+4H+2s20+4H+2s30+2H+2s35+2H+2s30+2H+2s20+2H+3s15+2H.

[0111] Process parameters:

[0112] The tension of a single fiber bundle is 20N;

[0113] The thickness of a single layer is 0.3 mm;

[0114] The total wrap thickness is 17.4 mm.

[0115] Epoxy Curing:

[0116] Curing steps:

[0117] The temperature rises to 75°C and the curing time is 2 hours;

[0118] The temperature was raised to 110°C and the curing time was 6 hours.

[0119] Final structure:

[0120] The outer surface of the winding layer is covered with a glass fiber outer protective layer, and the thickness of the protective layer is 17.4 mm.

[0121] Example 2: Composite material pressure vessel for making pressure vessel liner by injection molding of chopped fibers Preparation of pressure vessel liner head:

[0122] Material selection: The head material is made of recycled nylon 66 and chopped fibers, mixed in a mass ratio of 80:20.

[0123] Process parameters:

[0124] The injection material temperature is 220°C, the mold temperature is 80°C, and the injection pressure is 120MPa;

[0125] The holding time is 15s and the cooling time is 45s.

[0126] Production steps:

[0127] The aluminum alloy 6061 metal bottle mouth valve seat is embedded in the head mold after die pressing;

[0128] After the injection molding is completed, the mold is demoulded to obtain the head.

[0129] Preparation of pressure vessel liner cylinder:

[0130] Material selection: The barrel material is made of recycled nylon 66 and chopped fibers.

[0131] Process parameters:

[0132] Injection molding process, injection temperature is 240℃, mold temperature is 75℃, and injection pressure is 100MPa.

[0133] Welding head and cylinder:

[0134] Welding technology: ultrasonic welding technology.

[0135] The welding frequency is 18kHz;

[0136] The transducer amplitude is 18 μm;

[0137] The welding time is 1.2s.

[0138] Welding requirements: The welding surface is flat and free of defects.

[0139] Carbon fiber wound outer reinforcement:

[0140] Winding design basis: based on thin film theory calculation.

[0141] Process parameters:

[0142] The tension of a single fiber bundle is 18N;

[0143] The thickness of a single layer is 0.25 mm;

[0144] The total wrap thickness is 14.5 mm.

[0145] Epoxy Curing:

[0146] Curing steps:

[0147] The temperature rises to 70°C and the curing time is 1.5 hours;

[0148] The temperature was raised to 100°C and the curing time was 5 hours.

[0149] Final structure:

[0150] The outer surface of the winding layer is covered with a glass fiber outer protective layer, and the thickness of the protective layer is 0.25 mm.

[0151] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing a recycled carbon fiber reinforced lining, characterized in that: The following steps are involved: S1. According to the head mold, a pressure vessel liner head is manufactured by injection molding, and the metal bottle mouth valve seat (2) is embedded in the head mold. The injection molding material temperature is 200° C. to 300° C., the mold temperature is 70° C. to 80° C., and the injection molding pressure is 50 MPa to 150 MPa; S2. Making the inner shell of the pressure vessel by using a tube rolling process; S3. The head and the cylinder are combined by ultrasonic welding technology, the welding frequency is 15kHz~20kHz, the transducer amplitude is 15μm~20μm, and the welding time is 0.5s~1.5s; S4. Design the carbon fiber wrapped outer reinforcement layer (4) according to the minimum burst strength, the tension of a single fiber bundle is 15N to 20N, and the thickness of a single layer is 0.2mm to 0.3mm; S5. Curing the pressure vessel after wet winding.

2. The method for making a recycled carbon fiber reinforced lining according to claim 1, characterized in that: In step S1, the head material is selected from recycled nylon 6 or recycled nylon 66 and chopped fibers, and the processing method of the metal bottle mouth valve seat (2) in step S1 is not limited to molding or spinning.

3. The method for making a recycled carbon fiber reinforced lining according to claim 1, characterized in that: In step 2, the barrel material is selected from nylon plus prepreg or nylon plus chopped fibers, wherein nylon is divided into recycled nylon 6 or recycled nylon 66, and can be made by the following method: Made of recycled nylon 6 or recycled nylon 66 and carbon fiber prepreg, it is made through the tube rolling process; Or it can be made of recycled nylon 6 or recycled nylon 66 and chopped fibers through injection molding process.

4. The method for making a recycled carbon fiber reinforced lining according to claim 1, characterized in that: The design of the carbon fiber wound outer reinforcement layer (4) in step 4 is based on thin film theory calculation, and the winding layer angle range is determined to be 10° to 90° through grid theory.

5. The method for manufacturing a recycled carbon fiber reinforced lining according to claim 1, characterized in that: The curing step in step S5 includes: The temperature rises to 70-80°C and the curing time is 1.5-2.5h; The temperature rises to 100-120°C and the curing time is 5-7 hours.

6. The method for making a recycled carbon fiber reinforced lining according to claim 1, characterized in that: The wet winding in step S5 is specifically to pass the fiber through a resin impregnation tank and then wind it on the outer surface of the gas cylinder, wherein epoxy resin is placed in the impregnation tank, and the epoxy resin is a tough epoxy resin resistant to medium and high temperatures.

7. A composite pressure vessel with recycled carbon fiber reinforced lining, characterized in that: include: A recyclable liner (1), the recyclable liner (1) comprising a head and a cylinder, which are connected into one piece by welding; Two metal bottle mouth valve seats (2), which are respectively connected to the end caps of the recyclable liner (1) at both ends and are used to connect to the external pipeline of the pressure container; A sealing ring (3) is arranged at the joint between the metal bottle mouth valve seat (2) and the seal head of the recyclable liner (1); A carbon fiber wound outer reinforcement layer (4) is wound around the outside of the recyclable liner (1) to provide enhanced strength; The glass fiber outer protective layer (5) covers the outer side of the carbon fiber wound outer reinforcement layer (4) to provide external protection.

8. The composite pressure vessel with recycled carbon fiber reinforced liner according to claim 7, characterized in that: The metal bottle mouth valve seat (2) is made of aluminum alloy 6061.

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