Knitting process for carbon / carbon composite material prefabricated part of shaftless screw propeller

Abstract

The invention discloses a carbon / carbon composite material prefabricated part weaving process of a shaftless spiral propeller, and belongs to the technical field of carbon / carbon composite materials, and the carbon / carbon composite material prefabricated part weaving process comprises the following specific steps: manufacturing a metal shaftless spiral feeding propeller; carbon fiber prepreg is attached according to the shaftless spiral shape of the propeller to manufacture a carbon fiber prepreg material spiral, and a prefabricated part is obtained; the prefabricated part is cured, then demolding is conducted, the edge is polished, and a billet mold is obtained; fixing the blank model on a clamp of a braiding machine, braiding the blank model, and spraying resin on each layer of braided blank model; and curing the woven billet model, polishing, and finally carrying out chemical vapor deposition, carbonization, high-temperature treatment and dipping treatment to obtain the shaftless spiral carbon / carbon composite material. The obtained shaftless spiral carbon / carbon composite material is integrally formed, the strength of the product is improved, the shaftless spiral carbon / carbon composite material can replace a metal spiral propeller to prepare a negative electrode carbon material, the content of metal impurities is reduced, and the negative electrode manufacturing cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon / carbon composite materials, and specifically relates to a weaving process for a carbon / carbon composite preform of a shaftless screw propeller. Background Art

[0002] In recent years, the lithium-ion battery (hereinafter referred to as "lithium battery") industry in China has continued to grow.

[0004] The rapid growth of the lithium battery industry has brought a huge demand for high-performance and high-purity anode materials. Among them, the production of anode materials places higher requirements on the material propulsion system, especially for the strict control of material purity and metal impurity content. However, the metal screw propellers widely used in the current production of anode materials have the problem of metal impurity substitution, which not only affects the battery performance but also increases the difficulty and cost of subsequent purification processes.

[0005] In addition, traditional metal screw propellers have poor stability in high-temperature environments and are prone to shortened service life due to thermal expansion and corrosion. In contrast, carbon / carbon composite materials have the advantages of low density, high temperature resistance, corrosion resistance, and good thermal shock resistance. They have been widely used in fields such as aerospace and ships. For example, carbon / carbon composite propeller blades perform excellently in high-temperature and high-stress environments. Therefore, developing a weaving process for a carbon / carbon composite preform of a shaftless screw propeller suitable for the production of lithium battery anode materials has important practical significance. Summary of the Invention

[0006] Aiming at the above problems, the present invention provides a weaving process for a carbon / carbon composite preform of a shaftless screw propeller. The obtained shaftless carbon / carbon composite material is integrally formed, improving the strength of the product. It can replace metal screw propellers to prepare anode carbon materials, reduce the metal impurity content, and save the cost of anode production.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A weaving process for a carbon / carbon composite preform of a shaftless screw propeller, the specific steps are as follows:

[0009] S1: Fabricate a metal shaftless screw feeding propeller;

[0010] S2: Use carbon fiber prepreg to make a carbon fiber prepreg material helix according to the shaftless screw shape of the propeller obtained in step S1 to obtain a preform;

[0011] S3: Cure the preform obtained in S2, then demold and polish the edges to obtain a blank mold;

[0012] S4: Fix the embryo mold obtained in S3 firmly on the fixture of the knitting machine, knit the embryo mold, and spray resin for each layer knitted.

[0013] S5: Cure the knitted embryo mold, then perform grinding treatment, and finally perform chemical vapor deposition, carbonization, high temperature, and impregnation process treatments to obtain a shaftless spiral carbon / carbon composite material.

[0014] In a preferred embodiment, the thickness of the preform in step S2 is 10 - 15 mm.

[0015] In a preferred embodiment, the curing temperature in step S3 is 120 - 180 °C, and the curing time is 2 - 4 h.

[0016] In a preferred embodiment, the knitting material in step S4 is PAN-based carbon fiber, the thickness is 2 - 5 mm for each layer, the number of knitting layers is 10 - 15 layers, and the knitting speed of the knitting machine is 10 - 20 revolutions / min.

[0017] In a preferred embodiment, the resin in step S4 is epoxy resin, and the spraying thickness is 0.1 - 0.3 mm.

[0018] In a preferred embodiment, the curing temperature in step S5 is 150 - 200 °C, and the time is 3 - 5 h.

[0019] In a preferred embodiment, propane is introduced for chemical vapor deposition in step S5, the deposition temperature is 950 - 1200 °C, and the deposition time is 15 - 40 h.

[0020] In a preferred embodiment, the carbonization temperature in step S5 is 1500 - 1800 °C, and the carbonization time is 3 - 5 h.

[0021] In a preferred embodiment, the high temperature in step S5 is 2500 - 3000 °C, and the heat preservation time is 2 - 3 h.

[0022] In a preferred embodiment, the impregnating solution used for impregnation in step S5 is phenolic resin, and the impregnation time is 4 - 6 h.

[0023] Compared with the prior art, the beneficial effects of the present invention are: (1) The shaftless spiral carbon / carbon composite material prepared by the present invention realizes the integral molding of the overall structure, avoids the structural weak points caused by welding and splicing of traditional metal screw propellers, ensures the strength of the product. This integrated structure not only improves the mechanical strength of the product, but also reduces the performance degradation caused by fiber breakage or interfacial defects, thus significantly extending the service life; The shaftless spiral carbon / carbon composite material does not require machining treatment, which can save processing time and manufacturing costs;

[0024] (2) In the prior art, there are high requirements for the content of metal impurities in the production of anode materials. Currently, metal screw conveyors are basically used by everyone. Replacing metal screw conveyors with carbon / carbon composite materials can effectively reduce the introduction of metal impurities. This not only improves the purity of the anode materials of lithium batteries, but also reduces the difficulty and cost of subsequent purification processes, thus bringing significant economic benefits to lithium battery production enterprises;

[0025] (3) The carbon / carbon composite material produced by the present invention has excellent high-temperature performance. Its strength increases with the increase of temperature, and it can still maintain good structural stability below 2500 °C. This characteristic enables it to adapt to the high-temperature environment in the production of lithium batteries, avoiding deformation and damage caused by thermal expansion and corrosion of metal materials;

[0026] (4) The braiding process of the present invention combines three-dimensional braiding technology and resin transfer molding (RTM) process. Three-dimensional braiding technology can precisely control the arrangement and interweaving mode of fibers, improving the internal structure uniformity of preforms; at the same time, the RTM process avoids the phenomena of fiber layering disorder and thermal deformation during the molding process, reducing the possibility of delamination defects; this process combination not only improves product quality but also reduces manufacturing costs;

[0027] (5) The present invention makes preforms by laminating carbon fiber prepregs, which can precisely control the shape and thickness of the preforms, ensuring the smooth progress of subsequent braiding processes. Appropriate curing temperature and time guarantee the preliminary forming quality of the preforms. At the same time, the demolding and grinding processes further optimize the surface quality of the preforms. Braiding with PAN-based carbon fibers and combining with epoxy resin spraying can enhance the structural strength and corrosion resistance of the preforms. Through processes such as chemical vapor deposition, carbonization, high-temperature treatment, and impregnation, the densification and high-temperature performance of the materials are further improved. Description of the Drawings

[0028] Figure 1 Schematic diagram of the metal shaftless screw feeding propeller made in step S1 of Example 1;

[0029] Figure 2 Schematic diagram of the preform in step S2 of Example 1;

[0030] Figure 3 Schematic diagram of the demolding process in step S3 of Example 1;

[0031] Figure 4 Schematic diagram of the embryo mold obtained in step S3 of Example 1. Detailed Embodiments

[0032] To enable those skilled in the art to better understand the technical solution, the present invention will be described in detail below in conjunction with embodiments. The description in this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention.

[0033] Embodiment 1:

[0034] A weaving process for a carbon / carbon composite preform of a shaftless screw propeller, the specific steps are as follows:

[0035] S1: Use 3D printing to produce a metal shaftless screw feed propeller;

[0036] S2: Use carbon fiber prepreg to make a carbon fiber prepreg material helix by fitting the shaftless screw shape of the propeller obtained in step S1, to obtain a preform, and the thickness of the preform is 15 mm;

[0037] S3: Cure the preform obtained in S2, the curing temperature is 180 °C, the curing time is 2 h, then demold and polish the edge to obtain a blank mold;

[0038] S4: Fix the blank mold obtained in S3 on the fixture of the weaving machine, weave the blank mold, the weaving material is PAN-based carbon fiber, the thickness of each layer is 5 mm, the number of weaving layers is 10 layers, the weaving speed of the weaving machine is 15 revolutions / min, resin spraying is carried out for each woven layer, the resin is epoxy resin, and the spraying thickness is 0.2 mm;

[0039] S5: Cure the woven blank mold, the curing temperature is 150 °C, the time is 5 h, then polish it, and finally pass propane for chemical vapor deposition, the deposition temperature is 1200 °C, the deposition time is 15 h, and carry out carbonization, high-temperature, impregnation process treatment, the carbonization temperature is 1500 °C, the carbonization time is 5 h, to obtain a shaftless screw carbon / carbon composite material, the high-temperature temperature is 2500 °C, the heat preservation time is 3 h, and the impregnating liquid used for impregnation is phenolic resin, and the impregnation time is 6 h.

[0040] Embodiment 2:

[0041] A weaving process for a carbon / carbon composite preform of a shaftless screw propeller, the specific steps are as follows:

[0042] S1: Use 3D printing to produce a metal shaftless screw feed propeller;

[0043] S2: Use carbon fiber prepreg to make a carbon fiber prepreg material helix by fitting the shaftless screw shape of the propeller obtained in step S1, to obtain a preform, and the thickness of the preform is 10 mm;

[0044] S3: Cure the preform obtained in S2, the curing temperature is 160 °C, the curing time is 3 h, then demold and polish the edge to obtain a blank mold;

[0045] S4: Fix the embryo mold obtained in S3 firmly on the fixture of the knitting machine, and knit the embryo mold. The knitting material is PAN-based carbon fiber, with a thickness of 2 mm per layer and 15 knitting layers. The knitting speed of the knitting machine is 20 revolutions per minute. Resin spraying is carried out for each knitted layer. The resin is epoxy resin, and the spraying thickness is 0.3 mm.

[0046] S5: Cure the knitted embryo mold at a curing temperature of 180 °C for 4 h, then carry out grinding treatment, and finally introduce propane for chemical vapor deposition at a deposition temperature of 950 °C for 40 h, followed by carbonization, high-temperature, and impregnation process treatments. The carbonization temperature is 1800 °C and the carbonization time is 3 h to obtain a shaftless spiral carbon / carbon composite material. The high-temperature is 2700 °C and the heat preservation time is 2.5 h. The impregnating solution used for impregnation is phenolic resin, and the impregnation time is 4 h.

[0047] Example 3:

[0048] A knitting process for a shaftless spiral propeller carbon / carbon composite preform, the specific steps are as follows:

[0049] S1: Use 3D printing to make a metal shaftless spiral feeding propeller.

[0050] S2: Use carbon fiber prepreg to make a carbon fiber prepreg material spiral by fitting the shaftless spiral shape of the propeller obtained in step S1 to obtain a preform, and the thickness of the preform is 12 mm.

[0051] S3: Cure the preform obtained in S2 at a curing temperature of 120 °C for 4 h, then demold and grind the edges to obtain an embryo mold.

[0052] S4: Fix the embryo mold obtained in S3 firmly on the fixture of the knitting machine, and knit the embryo mold. The knitting material is PAN-based carbon fiber, with a thickness of 3 mm per layer and 13 knitting layers. The knitting speed of the knitting machine is 10 revolutions per minute. Resin spraying is carried out for each knitted layer. The resin is epoxy resin, and the spraying thickness is 0.1 mm.

[0053] S5: Cure the knitted embryo mold at a curing temperature of 200 °C for 3 h, then carry out grinding treatment, and finally introduce propane for chemical vapor deposition at a deposition temperature of 1000 °C for 35 h, followed by carbonization, high-temperature, and impregnation process treatments. The carbonization temperature is 1650 °C and the carbonization time is 4 h to obtain a shaftless spiral carbon / carbon composite material. The high-temperature is 3000 °C and the heat preservation time is 2 h. The impregnating solution used for impregnation is phenolic resin, and the impregnation time is 5 h.

[0054] Comparative Example 1:

[0055] A traditional metal screw propeller process, the specific steps are as follows: Stainless steel is used and processed by welding and machining to obtain a metal screw propeller.

[0056] Comparative Example 2:

[0057] The difference between this comparative example and Example 1 is that ordinary carbon fiber composite material is used instead of carbon-carbon composite material, and other process steps are the same as those in Example 1.

[0058] Comparative Example 3:

[0059] The difference between this comparative example and Example 1 is that the embryo mold of its propeller is manufactured and spliced in a segmented manner instead of being integrally formed.

[0060] Comparative Example 4:

[0061] The difference between this comparative example and Example 1 is that in step S4, a traditional RTM process is used to replace the three-dimensional braiding + resin transfer molding (RTM) process. Specifically, it is a process of injecting resin into a closed mold to infiltrate the reinforcing material and cure it.

[0062] The shaftless screw propellers produced in the above examples and comparative examples are used in the production of the negative electrode material of lithium batteries, and the obtained performance parameters are compared. The comparison results are shown in Table 1.

[0063] Table 1

[0064]

[0065]

[0066] It should be noted that in this article, the terms: including, containing and any other variants are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or device. Specific examples are used in this article to elaborate on the principle and implementation manner of the technical solution of the present invention. The description of the above examples is only used to help understand the method of the present invention and its core idea. The above is only the preferred implementation manner of the present invention. It should be pointed out that due to the limited nature of written expression and objectively there are infinite specific structures. For those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements, retouches or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, retouches, changes or combinations, or directly applying the concept and technical solution of the present invention to other occasions without improvement, should all be regarded as the protection scope of the present invention.

Claims

1. A braiding process for a carbon / carbon composite material preform of a shaftless screw propeller, characterized in that: The specific steps are as follows: S1: Fabrication of a metal shaftless screw feed propeller; S2: using the carbon fiber prepreg to bond the propeller shaftless spiral shape obtained in step S1 to make a carbon fiber prepreg material spiral to obtain a preform; S3: curing the prefabricated part obtained in S2, demoulding it, grinding its edges, and obtaining a mold; S4: Fix the mold obtained in S3 on the fixture of the braiding machine, weave the mold, and spray resin on each weaving layer; S5: The woven mold is solidified, polished, and finally subjected to chemical vapor deposition, carbonization, high temperature, and impregnation processes to obtain an axisless spiral carbon / carbon composite material.

2. A braiding process for a carbon / carbon composite material preform of a shaftless screw propeller according to claim 1, characterized in that: The thickness of the preform in step S2 is 10-15 mm.

3. The braiding process of a carbon / carbon composite material preform of a shaftless screw propeller according to claim 1 is characterized in that: In step S3, the curing temperature is 120-180° C. and the curing time is 2-4 hours.

4. The braiding process of a carbon / carbon composite material preform of a shaftless screw propeller according to claim 1 is characterized in that: In the step S4, the braided material is PAN-based carbon fiber, the thickness of each layer is 2-5 mm, the number of braided layers is 10-15 layers, and the braiding speed of the braiding machine is 10-20 revolutions / min.

5. The braiding process of a carbon / carbon composite material preform of a shaftless screw propeller according to claim 1, characterized in that: The resin in step S4 is epoxy resin, and the spraying thickness is 0.1-0.3 mm.

6. The braiding process of carbon / carbon composite material preform of shaftless screw propeller according to claim 1 is characterized in that: In step S5, the curing temperature is 150-200° C. and the curing time is 3-5 hours.

7. The braiding process of carbon / carbon composite material preform of shaftless screw propeller according to claim 1 is characterized in that: In the step S5, propane is introduced to perform chemical vapor deposition, the deposition temperature is 950-1200° C., and the deposition time is 15-40 hours.

8. The braiding process of carbon / carbon composite material preform of shaftless screw propeller according to claim 1 is characterized in that: In step S5, the carbonization temperature is 1500-1800° C., and the carbonization time is 3-5 hours.

9. The braiding process of carbon / carbon composite material preform of shaftless screw propeller according to claim 1, characterized in that: In step S5, the high temperature is 2500-3000° C., and the insulation time is 2-3 hours.

10. The braiding process of carbon / carbon composite material preform of shaftless screw propeller according to claim 1, characterized in that: The impregnation liquid used in the step S5 is phenolic resin, and the impregnation time is 4-6 hours.

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