A carbon / carbon composite material and its preparation method, realization device and application

Abstract

The present invention belongs to the technical field of composite materials, and discloses a carbon / carbon composite material and its preparation method, realization device and application. The carbon / carbon composite material mainly consists of a carbon matrix and a three-dimensional woven carbon fiber preform located therein; the preparation method is: the three-dimensional woven carbon fiber preform is impregnated with a liquid high-carbon substance, and then the preform is subjected to a first and second stage carbon treatment, a plasma treatment, and a third stage carbon treatment (or the semi-finished product is subjected to the first and second stage carbon treatment, and then impregnated into a mixture of carbon aerogel powder and liquid high-carbon substance and reacted in a reactor, and then subjected to a third stage carbon treatment), so as to obtain the carbon / carbon composite material; the device used includes semi-finished product continuous processing equipment, carbonization equipment, and plasma treatment equipment; the application is: used as an electrode of a structural battery. The carbon / carbon composite material prepared by the present invention has regular pore distribution, improves the ion loading capacity and has good mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials and relates to a carbon / carbon composite material and a preparation method, a realization device and an application thereof. Background Art

[0002] With the rapid progress of new energy technology, the transportation industry is actively moving towards a low-carbon, electrified future. In this transformation process, the core elements of the new energy transportation field, such as high-performance endurance, spacious and comfortable space, and economical and efficient operation, are all deeply affected by the key technologies of energy storage batteries. Due to the limitations of energy storage mechanism and structural design, traditional batteries face problems such as low energy density, large volume, poor adaptability to complex environments, and potential safety risks, making it difficult to meet the growing diversified needs of new energy transportation. As a rising star in energy storage technology, new energy structural batteries stand out with their significant advantages such as lightweight design, excellent energy density, high load stability, and long service life. More importantly, it is expected to reduce the dependence on a large number of conductive agents, activators and other materials in traditional electrode manufacturing, and open up an innovative path for the development of new energy green energy storage technology. Therefore, the application research of new materials in the field of structural batteries has attracted much attention, among which carbon fiber and its composite materials are favored due to their unique performance characteristics. The application of carbon fiber and its composite materials in electrode preparation not only broadens the selection range of structural battery materials, but also provides the possibility of achieving higher performance, lower cost, and more environmentally friendly energy storage solutions. With the continuous breakthrough of technology, the application prospects of carbon fiber composite materials in the field of new energy transportation will be broader.

[0003] In the application of carbon fiber and its composite materials to prepare electrodes, they can be roughly divided into the following categories according to the material type:

[0004] (1) Directly using carbon fiber as electrode, such as disclosed in CN104577052A, CN115863780A and CN116565329A.

[0005] (2) Adding functional substances into the carbon fiber precursor organic liquid and spinning them into fibers, and using the carbon-based composite fibers containing the functional substances obtained after carbonization as electrodes, as disclosed in CN109273276B.

[0006] (3) In the material form of carbon fiber film, carbon fiber felt, carbon fiber cloth, etc., which still retains the original carbon fiber properties and basic structural characteristics, other functional substances are attached to the surface after surface modification to serve as electrodes, such as the disclosures of CN115966652A, CN1107142098B and CN105513829A.

[0007] (4) Using carbon fiber composite materials as electrodes. For example, Ding Yinghui described carbon fiber reinforced polymer-based composite materials as structural battery electrodes in "Research Progress of Carbon Fiber Composite Materials for Structural Energy Storage". For example, CN115976434A disclosed carbon fiber reinforced metal-based composite materials as electrodes, and CN1075031A disclosed carbon / carbon composite materials as battery electrodes.

[0008] The above-mentioned (1)-(3) electrode materials are essentially based on the original carbon fiber as the skeleton, and are directly used as electrodes after surface modification or internal component modification. However, both physical and chemical surface modification methods will damage the surface structure of the carbon fiber, and its mechanical properties will be greatly reduced. In addition, indicators such as the uniformity of surface functional material deposition and the uniformity of internal functional material dispersion will directly affect the performance of the electrode. Secondly, when the positive electrode is made while retaining the carbon fiber form, a large amount of conductive agents, adhesives, activating materials and even metal collectors and other auxiliary materials are required, which is easy to cause waste of rare resources and cause environmental pollution risks, and the cost of the electrode is increased in disguise. More importantly, after the carbon fiber is combined with lithium / sodium metal ions, the insertion and extraction of lithium / sodium ions during the charging and discharging process will cause the carbon fiber to expand and contract, which will cause the carbon fiber electrode structure to decompose and further affect the cycle stability of the structural battery. Ultimately, the electrochemical properties of the carbon fiber electrode lithium-ion battery, such as energy density, cycle stability and service life, are far inferior to those of commercial lithium-ion batteries, and the commercialization process of carbon fiber electrode structural batteries is seriously hindered.

[0009] Compared with the above-mentioned (1)-(3) electrode materials, the above-mentioned (4) electrode materials show more significant advantages. They can not only effectively avoid the damage to the surface structure of carbon fiber by physical and chemical surface modification and reduce the loss of mechanical properties, but also optimize the microstructure of the electrode through the reasonable design of the composite material, thereby improving the energy density, cycle stability and service life. Among the above-mentioned 4 types of electrode materials, although carbon fiber reinforced polymer matrix composite materials can improve certain performance, their mechanical properties are unbalanced, their crack diffusion resistance is limited, and the polymer matrix is ​​not conductive, which limits the improvement of energy density and specific capacity. Carbon fiber reinforced metal matrix composite materials face challenges in lightweight and interface bonding strength. The direct contact between carbon fiber and metal can easily lead to structural embrittlement and affect the overall performance. In contrast, carbon / carbon composite materials, with their balanced mechanical properties, excellent crack diffusion resistance and enhanced conductivity, provide a more ideal solution for structural battery electrodes in the field of new energy transportation, and are expected to break through the existing technical bottleneck and promote the commercialization of carbon fiber electrode structural batteries.

[0010] For example, the literature (Highly Conductive Carbon / Carbon Composites as AdvancedMultifunctional Anode Materials for Structural Lithium-ion Batteries. Advanced Functional Materials, 34(40), 2403729 (1-11).) discloses the use of carbon fiber felt as reinforcement, methane as matrix carbon source, and ICVI (constant temperature chemical vapor deposition) method to prepare carbon / carbon composite electrodes. The literature characterizes the micromorphology of carbon / carbon composite electrodes, studies the electrochemical and mechanical properties of carbon / carbon composite electrodes, the electrochemical properties of assembled battery packs, etc., and discusses the effect of carbon / carbon material microstructure on ion / electron transport and the effect of its unique structure on Li + The storage mechanism, however, has the following problems:

[0011] ①Pore size and distribution are not ideal:

[0012] The pores originate from internal defects in the production and molding of composite materials and artificial processing. Their sizes range from micrometer to nanometer scales and their distribution is random. Although they can improve the ion storage capacity of carbon / carbon composites to a certain extent, they also inevitably weaken their comprehensive mechanical properties.

[0013] ② Insufficient mechanical properties:

[0014] The reinforcement of carbon / carbon composite materials is short fiber felt, and the internal fibers are only connected by overlapping and interlacing, resulting in insufficient static performance. The structure is difficult to withstand complex external loads, has limited dynamic performance, is prone to rapid failure, and cannot meet the application requirements of structural batteries.

[0015] ③Limitations of production process:

[0016] The isothermal chemical vapor deposition (ICVI) process is used to deposit the elemental carbon matrix, which requires high temperature (2400°C) and long time (2 hours) processing, high energy consumption and low efficiency.

[0017] Therefore, it is necessary to propose a carbon / carbon composite material and a preparation method, a realization device and an application thereof that can solve at least one of the above problems. Summary of the invention

[0018] The purpose of the present invention is to solve the problems existing in the prior art and to provide a carbon / carbon composite material and a preparation method, a realization device and an application thereof.

[0019] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0020] A method for preparing a carbon / carbon composite material (referred to as a method for preparing a carbon / carbon composite material C), comprising: impregnating a three-dimensional woven carbon fiber preform with a liquid high-carbon substance and then curing the preform to obtain a semi-finished product, and sequentially performing a first-stage carbon treatment, a second-stage carbon treatment, a plasma treatment, and a third-stage carbon treatment on the semi-finished product to obtain a carbon / carbon composite material;

[0021] During the carbon treatment process, in the internal space of the three-dimensional woven carbon fiber preform, the high-carbon-containing material filled undergoes a pyrolysis reaction under high temperature conditions, resulting in the complete or partial conversion of other small molecules except the C element into gaseous substances. A portion of the gaseous substances will escape, and the other portion of the gaseous substances will leave nano-scale pores inside the material. The remaining residual carbon undergoes a micro-condensation process and gradually aggregates into a dense carbon matrix structure. An excessively high residual carbon rate will reduce the formation of nano-scale pores and reduce the ion adsorption capacity of the material, while an excessively low residual carbon rate will lead to an increase in the number and size of pores, and even cause excessive aggregation of pores to form internal defects, thereby significantly weakening the mechanical properties of the material. Therefore, the present invention controls the residual carbon rate of the high-carbon-containing material to be 35%-50%;

[0022] The impregnation adopts vacuum injection infiltration technology;

[0023] The temperature of the first stage carbon treatment is 900-1100°C, and the time is 5-10h; the temperature of the second stage carbon treatment is 100-400°C higher than that of the first stage carbon treatment, and the time of the second stage carbon treatment is 1-3h shorter than that of the first stage carbon treatment; the temperature of the third stage carbon treatment is 200-500°C higher than that of the second stage carbon treatment, and the time of the third stage carbon treatment is 2-7h shorter than that of the second stage carbon treatment.

[0024] The temperature of the first stage of carbon treatment just reaches the temperature (850-900℃) at which the carbonization reaction of high carbon-containing substances occurs. The carbonization temperature allows the reaction to occur, but the reaction efficiency will not be too fast, and the exhaust process is relatively slow. The semi-finished product completes the full thickness thermal radiation penetration and carbonization process under the condition of producing a small exhaust volume for a long time. In this process, the inner layer of the semi-finished product serves as the source of small molecular bubbles, and most of the small molecular bubbles can be smoothly removed to achieve densification.

[0025] The second stage carbon treatment increases the temperature and shortens the time based on the first stage carbon treatment, which can accelerate the speed of thermal radiation penetrating the interior, so that some small molecular bubbles can be discharged from the middle layer of the semi-finished product, while retaining some small molecular bubbles in the middle layer of the semi-finished product to form nano-scale pores.

[0026] Adding plasma treatment after the second stage carbon treatment is to assist in breaking through a dense film on the surface during the carbonization process. At the same time, during the continuous bombardment and penetration of plasma, nano-scale pores will be assisted in the outer layer of the semi-finished product. This complements the third stage carbon treatment, forming more nano-scale pores in the outer layer of the semi-finished product than in the middle layer.

[0027] The present invention, by controlling the conditions of carbon treatment at each stage, can ultimately obtain a carbon / carbon composite material which is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein, and has an overall multi-layer integrated structure, a dense inner layer, a porous middle layer and an outer layer, the pores of which are mainly nanoscale pores, and the number of pores in the outer layer is greater than that in the middle layer.

[0028] As the preferred technical solution:

[0029] As described above, a method for preparing a carbon / carbon composite material, wherein the high-carbon-content substance is phenolic resin, polyimide resin, asphalt, etc., and the viscosity of the high-carbon-content substance at 25°C is 20-2000cps; the injection pressure during impregnation is 0.1-1bar, the greater the viscosity of the high-carbon-content substance, the greater the corresponding injection pressure, and the volume ratio of the high-carbon-content substance to the three-dimensional woven carbon fiber preform is 35-46:47-62.5; the curing temperature is 80-190°C, the pressure is 0.1-2MPa, and the time is 0.2-3h.

[0030] In the method for preparing a carbon / carbon composite material as described above, the plasma treatment uses a plasma emitter with a power of 500-900 W and a distance of 3-6 cm from the surface of the semi-finished product, and the plasma treatment time is 10-60 min.

[0031] A method for preparing a carbon / carbon composite material as described above, wherein the device used to prepare a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial, and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, wherein the number of the angle wheel, the dial, and the braiding yarn carrier base is multiple, the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate;

[0032] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0033] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0034] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0035] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0036] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0037] n>2; for the cutouts in each 6-cut circular plate of the nth layer that are not opposite to other cutouts, the braiding yarn carrier base in each cutout is filled with one cutout of a 2-cut circular plate, and the other cutout of the 2-cut circular plate is filled with another braiding yarn carrier base;

[0038] Or, n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the base of the knitting yarn carrier in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base, and the 2-cut circular plate is recorded as dial a; the base of the knitting yarn carrier in cut b is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base, and the 2-cut circular plate is recorded as dial a; One cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-cut circular plate is recorded as dial b; the braiding yarn carrier base in the cut c fills one cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c;

[0039] The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are simultaneously controlled to rotate 180° in the same direction. The angle wheels and dials are controlled to rotate in opposite directions. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

[0040] A method for preparing a carbon / carbon composite material as described above, wherein the device used to prepare a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial, and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, wherein the number of the angle wheel, the dial, and the braiding yarn carrier base is multiple, the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate;

[0041] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0042] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0043] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0044] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0045] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0046] n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the braiding yarn carrier base in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial a; the braiding yarn carrier base in cut b is filled with one One cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-cut circular plate is recorded as dial b; the braiding yarn carrier base in the cut c fills one cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c;

[0047] The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling all yarn carriers except the woven yarn carrier b to carry yarns, all the yarns are bundled and then rolled up. During the rolling up process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, all the dials except the dial b are rotated 180° at the same time, the rotation directions of the dial a and the dial c are controlled to be opposite, and the rotation directions of the other dials and angle wheels except the dials a~c are controlled to be opposite. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

[0048] A method for preparing a carbon / carbon composite material as described above, wherein the device used to prepare a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial, and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, wherein the number of the angle wheel, the dial, and the braiding yarn carrier base is multiple, the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate;

[0049] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0050] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0051] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0052] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0053] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0054] n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the braiding yarn carrier base in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial a; the braiding yarn carrier base in cut b is not filled with one cut of a 2-cut circular plate; the braiding yarn carrier base in cut c is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial c;

[0055] The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are rotated 180° at the same time. The rotation directions of dial a and dial c are controlled to be opposite, and the rotation directions of other dials and angle wheels except dial a and dial c are controlled to be opposite. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

[0056] In the method for preparing a carbon / carbon composite material as described above, at least one corner wheel is provided with a lining yarn carrier.

[0057] In the method for preparing a carbon / carbon composite material as described above, a lining yarn carrier is provided on the corner wheel, the number of the lining yarn carrier is 1, and the lining yarn carrier is located at the center of the corner wheel.

[0058] In the method for preparing a carbon / carbon composite material as described above, a corner wheel is provided with lining yarn carriers, the number of the lining yarn carriers is greater than 1, and the lining yarn carriers are distributed in a circle around the central axis of the corner wheel.

[0059] In the method for preparing a carbon / carbon composite material as described above, a circular slide rail is also provided on the corner wheel provided with a lining yarn carrier, the center of the circular slide rail is located on the central axis of the corner wheel, and the lining yarn carrier is slidably connected to the circular slide rail.

[0060] In the method for preparing a carbon / carbon composite material as described above, each corner wheel has a matching corner wheel drive motor, each dial has a matching dial drive motor, a pair of rollers are provided above the braiding yarn carrier, and a winding wheel is provided above the pair of rollers.

[0061] In the method for preparing a carbon / carbon composite material as described above, a metal bunching ring is provided above the braided yarn carrier, and the metal bunching ring is located below a pair of rollers and is grounded.

[0062] The present invention also provides a device for implementing a method for preparing a carbon / carbon composite material as described above, comprising semi-finished product continuous processing equipment, carbonization equipment, and a plasma treatment device;

[0063] The semi-finished product continuous processing equipment includes a high-carbon material injection machine and a preparation device for three-dimensional woven carbon fiber preforms arranged in sequence along the conveying direction, a preforming device, an infiltration and curing integrated molding mold, a post-processing device, a drawing device, and a cutting device.

[0064] After the three-dimensional woven carbon fiber preform is formed, it first passes through a preforming device, which can compress the outer dimensions of the three-dimensional woven carbon fiber preform to facilitate entry into the entrance of the infiltration and curing integrated molding mold, and prevent the infiltration and curing integrated molding mold from damaging the three-dimensional woven carbon fiber preform when the fluffy size enters, and then passes through the resin injection area and the heating and curing area of ​​the infiltration and curing integrated molding mold in sequence. In the resin injection area, high-carbon-content material is injected and infiltrated into the interior of the three-dimensional woven carbon fiber preform by a high-carbon-content material injection machine at a certain flow rate and pressure. In the heating and curing area, the high-carbon-content material impregnated in the three-dimensional woven carbon fiber preform is heat-cured, and part of the gas is discharged at this time. The small amount of gas that is not discharged inside forms micropores, and then passes through a post-processing device for shaping and eliminating internal residual stress, and then passes through a drafting device, and then passes through a cutting device, and is cut into suitable lengths for standby use.

[0065] The present invention adopts a continuous equipment group to operate in the stage of converting carbon fiber into semi-finished products to improve production efficiency; and when it comes to the carbon processing link, it is switched to an intermittent equipment group for operation. Despite this, the carbonization equipment design allows large quantities of semi-finished products to be loaded at one time, so the economic efficiency of the carbonization process is still considerable.

[0066] The present invention also provides a carbon / carbon composite material prepared by the preparation method of a carbon / carbon composite material as described in any of the above items, which is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein; the whole has a multi-layer integrated structure, the inner layer is dense, the middle layer and the outer layer are porous and the pores are mainly nano-scale pores, and the number of pores in the outer layer is greater than that in the middle layer.

[0067] As the preferred technical solution:

[0068] A carbon / carbon composite material as described above, wherein the volume proportion of the inner layer of the carbon / carbon composite material is 70-75%, the volume proportion of the middle layer is 10-15%, and the volume proportion of the outer layer is 10-15%, and the volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material;

[0069] The overall porosity of the carbon / carbon composite material is 2.5-7%, the pore volume of the outer layer accounts for 65-75% of the overall pore volume of the carbon / carbon composite material, the nanoscale pore volume accounts for 60-70% of all pore volumes, and the average pore diameter of the nanoscale pores is 5-70nm;

[0070] The density of carbon / carbon composite materials is 0.7-1.8g / cm 3 , tensile strength is 600-800MPa, tensile modulus is 250-400GPa, bending strength is 450-700MPa, chemical stability is strong, can withstand high temperatures of thousands of degrees and maintain normal mechanical properties without loss, hardness is 10-60GPa, which can better meet the complex requirements of structural batteries for lightweight and functionalization;

[0071] Since the inner layer of the carbon / carbon composite material of the present invention is dense, the hardness of the carbon / carbon composite material can be as high as 10-60 GPa;

[0072] The tensile strength of the carbon / carbon composite materials in the prior art is about 100-200 MPa, which is improved by 60-180% in the present invention. The flexural strength of the carbon / carbon composite materials in the prior art is about 50-210 MPa, which is improved by 80-200% in the present invention. The carbon / carbon composite materials in the present invention can reduce the range of crack propagation inhibition by 60-85% compared with the prior art, which is mainly attributed to the use of a three-dimensional woven carbon fiber preform different from the prior art in the present invention.

[0073] The present invention also provides a use of a carbon / carbon composite material as described in any one of the above items, which is used as an electrode of a structural battery.

[0074] As the preferred technical solution:

[0075] As described above, the negative electrode of the structural battery is a carbon / carbon composite material, and the positive electrode is a carbon / carbon composite material that has been treated with lithium / sodium ions for attachment. The carbon / carbon composite material proposed in the present invention does not require additional binders, conductive additives, and auxiliary treatments of active substances after processing, and can be directly used as an independent positive electrode after lithium / sodium ion attachment treatment. Compared with other existing electrode application methods, the electrode application proposed in the present invention is simpler and faster, and has more advantages in reducing the cost of rare precious metal resources for batteries. The structural battery using the electrode of the present invention has greater potential for improving the electrochemical performance and load structure stability.

[0076] For the application described above, the impact strength of the structural battery (the impact strength of the structural battery prepared in each embodiment is measured with reference to ASTM D7136 / D7136M-12 "Standard Test Method for Measurement of Drop Weight Impact Loss of Fiber Reinforced Polymer Collective Materials"; wherein the hemispherical drop weight has a diameter of 16 mm and a mass of 5.5 kg) is 200-300 MPa, and the specific capacity retention rate after 400 cycles at 0.5 times the rated capacity is 75-88%; compared with the structural battery of the prior art, the structural battery of the present invention can reduce weight by 30-50%, improve impact strength by about 60-80%, and maintain specific capacity after 400 cycles at 0.5 times the rated capacity. The specific capacity retention rate after 400 times can be increased by 50-150%. This is because the middle and outer layers of the carbon / carbon composite material are porous and the pores are mainly nanoscale pores. The number of pores in the outer layer is greater than that in the middle layer. When the carbon / carbon composite material is used as an electrode, the conductive factor has a considerable load in the outer and middle layers. At the same time, the conductive factor can be easily removed freely to give full play to the efficient charge and discharge performance. The three-dimensional woven structure and the filled carbon matrix synergistically reduce the risk of irreversible damage to the internal structure caused by the conductive factor due to high-frequency embedding and removal of the carbon fiber in the electrode, which is conducive to maintaining the structural stability of the electrode. The introduction of the three-dimensional woven carbon fiber preform structure is conducive to the improvement of its impact resistance.

[0077] The present invention also provides another method for preparing a carbon / carbon composite material (referred to as a method for preparing a carbon / carbon composite material D), comprising the following steps:

[0078] (a) impregnating a three-dimensional woven carbon fiber preform with a liquid high-carbon-content substance and then curing the preform to obtain a semi-finished product a;

[0079] (b) sequentially performing a first-stage carbon treatment and a second-stage carbon treatment on the semi-finished product a to obtain a semi-finished product b;

[0080] The temperature of the first stage carbon treatment is 900-1100°C and the time is 5-10h; the temperature of the second stage carbon treatment is 100-400°C higher than that of the first stage carbon treatment, and the time of the second stage carbon treatment is 1-3h shorter than that of the first stage carbon treatment;

[0081] (c) impregnating the semi-finished product b into a mixture of carbon aerogel powder and liquid high carbon content material in a volume ratio of 3-9:100, storing the mixture in a reactor, maintaining the temperature of the reactor at 45-75°C, and performing 4-6 cycles of "gradually pressurizing the reactor to 2-5 MPa and maintaining the pressure for 2-4 hours" to obtain a semi-finished product c, wherein the carbon aerogel powder is the carbon aerogel powder that has been washed with a strong oxidizing activator and dried;

[0082] (d) performing a third-stage carbon treatment on the semi-finished product c to obtain a carbon / carbon composite material;

[0083] The temperature of the third stage carbon treatment is 200-500°C higher than that of the second stage carbon treatment, and the time of the third stage carbon treatment is 2-7h shorter than that of the second stage carbon treatment;

[0084] All impregnations were performed using vacuum injection infiltration technology;

[0085] The residual carbon rate of all high-carbon materials is in the range of 35%-50%. The reason for setting the residual carbon rate in this way is the same as that of the preparation method C of the carbon / carbon composite material.

[0086] The preparation method C of the carbon / carbon composite material and the preparation method D of the carbon / carbon composite material of the present invention can both obtain carbon / carbon composite materials with the same structure. The main difference between the two is that the preparation method C of the carbon / carbon composite material performs plasma treatment before the third-stage carbon treatment, and the preparation method D of the carbon / carbon composite material impregnates a mixture of carbon aerogel powder and liquid high-carbon-content material before the third-stage carbon treatment. The carbon aerogel is rich in a large number of nanoscale pore structures. Adding carbon aerogel is equivalent to physically adding nanoscale pores to the high-carbon-content material. The present invention selects carbon aerogel powder that has been cleaned and dried with a strong oxidizing activator because the carbon aerogel powder has a low probability of agglomeration in the high-carbon-content material and has good dispersion uniformity.

[0087] As the preferred technical solution:

[0088] A method for preparing a carbon / carbon composite material as described above, wherein all high-carbon-content substances are phenolic resin, polyimide resin, asphalt, etc., and the viscosity of all high-carbon-content substances at 25°C is 20-2000cps; the injection pressure during all impregnation is 0.1-1bar, the greater the viscosity of the high-carbon-content substance, the greater the corresponding injection pressure, the volume of the high-carbon-content substance in step (a) is 54-71% of the total volume of the high-carbon-content substances in step (a) and step (c), and the ratio of the total volume of the high-carbon-content substances in step (a) and step (c) to the volume of the three-dimensional woven carbon fiber preform is 35-45:49-62; the curing temperature is 80-190°C, the pressure is 0.1-2MPa, and the time is 0.2-3h.

[0089] A method for preparing a carbon / carbon composite material as described above, wherein the device used to prepare a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial, and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, wherein the number of the angle wheel, the dial, and the braiding yarn carrier base is multiple, the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate;

[0090] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0091] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0092] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0093] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0094] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0095] n>2; for the cutouts in each 6-cut circular plate of the nth layer that are not opposite to other cutouts, the braiding yarn carrier base in each cutout is filled with one cutout of a 2-cut circular plate, and the other cutout of the 2-cut circular plate is filled with another braiding yarn carrier base;

[0096] Or, n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the base of the knitting yarn carrier in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base, and the 2-cut circular plate is recorded as dial a; the base of the knitting yarn carrier in cut b is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base, and the 2-cut circular plate is recorded as dial a; One cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-cut circular plate is recorded as dial b; the braiding yarn carrier base in the cut c fills one cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c;

[0097] The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are simultaneously controlled to rotate 180° in the same direction. The angle wheels and dials are controlled to rotate in opposite directions. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

[0098] A method for preparing a carbon / carbon composite material as described above, wherein the device used to prepare a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial, and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, wherein the number of the angle wheel, the dial, and the braiding yarn carrier base is multiple, the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate;

[0099] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0100] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0101] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0102] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0103] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0104] n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the braiding yarn carrier base in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial a; the braiding yarn carrier base in cut b is filled with one One cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-cut circular plate is recorded as dial b; the braiding yarn carrier base in the cut c fills one cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c;

[0105] The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling all yarn carriers except the woven yarn carrier b to carry yarns, all the yarns are bundled and then rolled up. During the rolling up process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, all the dials except the dial b are rotated 180° at the same time, the rotation directions of the dial a and the dial c are controlled to be opposite, and the rotation directions of the other dials and angle wheels except the dials a~c are controlled to be opposite. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

[0106] A method for preparing a carbon / carbon composite material as described above, wherein the device used to prepare a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial, and a braiding yarn carrier, wherein the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, wherein the number of the angle wheel, the dial, and the braiding yarn carrier base is multiple, the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate;

[0107] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0108] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0109] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0110] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0111] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0112] n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the braiding yarn carrier base in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial a; the braiding yarn carrier base in cut b is not filled with one cut of a 2-cut circular plate; the braiding yarn carrier base in cut c is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial c;

[0113] The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are rotated 180° at the same time. The rotation directions of dial a and dial c are controlled to be opposite, and the rotation directions of other dials and angle wheels except dial a and dial c are controlled to be opposite. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

[0114] In the method for preparing a carbon / carbon composite material as described above, at least one corner wheel is provided with a lining yarn carrier.

[0115] In the method for preparing a carbon / carbon composite material as described above, a lining yarn carrier is provided on the corner wheel, the number of the lining yarn carrier is 1, and the lining yarn carrier is located at the center of the corner wheel.

[0116] In the method for preparing a carbon / carbon composite material as described above, a corner wheel is provided with lining yarn carriers, the number of the lining yarn carriers is greater than 1, and the lining yarn carriers are distributed in a circle around the central axis of the corner wheel.

[0117] In the method for preparing a carbon / carbon composite material as described above, a circular slide rail is also provided on the corner wheel provided with a lining yarn carrier, the center of the circular slide rail is located on the central axis of the corner wheel, and the lining yarn carrier is slidably connected to the circular slide rail.

[0118] In the method for preparing a carbon / carbon composite material as described above, each corner wheel has a matching corner wheel drive motor, each dial has a matching dial drive motor, a pair of rollers are provided above the braiding yarn carrier, and a winding wheel is provided above the pair of rollers.

[0119] In the method for preparing a carbon / carbon composite material as described above, a metal bunching ring is provided above the braided yarn carrier, and the metal bunching ring is located below a pair of rollers and is grounded.

[0120] The present invention also provides a carbon / carbon composite material prepared by the preparation method of a carbon / carbon composite material as described in any of the above items, which is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein; the whole has a multi-layer integrated structure, the inner layer is dense, the middle layer and the outer layer are porous and the pores are mainly nano-scale pores, and the number of pores in the outer layer is greater than that in the middle layer.

[0121] As the preferred technical solution:

[0122] A carbon / carbon composite material as described above, wherein the volume proportion of the inner layer of the carbon / carbon composite material is 70-75%, the volume proportion of the middle layer is 10-15%, and the volume proportion of the outer layer is 10-15%, and the volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material;

[0123] The overall porosity of the carbon / carbon composite material is 2.5-7%, the pore volume of the outer layer accounts for 65-75% of the overall pore volume of the carbon / carbon composite material, the nanoscale pore volume accounts for 60-70% of all pore volumes, and the average pore diameter of the nanoscale pores is 5-70nm;

[0124] The density of carbon / carbon composite materials is 0.7-1.8g / cm 3 , tensile strength is 600-800MPa, tensile modulus is 250-400GPa, flexural strength is 450-700MPa, and hardness is 10-60GPa.

[0125] The present invention also provides a use of a carbon / carbon composite material as described in any one of the above items, which is used as an electrode of a structural battery.

[0126] As the preferred technical solution:

[0127] As described above, the negative electrode of the structural battery is a carbon / carbon composite material, and the positive electrode is a carbon / carbon composite material treated with lithium / sodium ions.

[0128] For the application described above, the impact strength of the structural battery is 200-300MPa, and the specific capacity retention rate is 75-88% after 400 cycles at 0.5 times the rated capacity.

[0129] Principle of the invention:

[0130] The present invention can solve the problems existing in the literature (Highly Conductive Carbon / Carbon Composites as Advanced Multifunctional Anode Materials for Structural Lithium-lon Batteries. Advanced Functional Materials, 34(40), 2403729 (1-11).), and the specific reasons are as follows:

[0131] In response to problem ①, the present invention successfully reduces the generation of unnecessary pores (such as cracks and micron-sized pores) by using vacuum injection infiltration technology, carbon aerogel, etc., which are generally regarded as defects that damage material properties. At the same time, it also promotes a significant increase in required pores (especially nano-sized pores), so that as many nano-sized pores as possible can be formed in specific areas of the elemental carbon matrix in the preform.

[0132] The present invention proposes a method of high temperature treatment in stages for precisely controlling the pore distribution in the preform. This method can subjectively design the distribution of pores within the contour of the preform from the inside out, thereby achieving precise control of the pore structure. The interior of the preform is designed to be as dense as possible to reduce the number of pores, thereby maintaining the mechanical properties of the composite material unaffected. Within a certain layer thickness range extending inward from the outer surface of the preform, a proper amount of pores are distributed, and the presence of these pores can effectively improve the ion storage capacity of the composite material.

[0133] Therefore, the present invention not only solves the problem of unsatisfactory pore size and distribution, but also successfully finds an ideal balance between improving ion storage capacity and maintaining comprehensive mechanical properties. This breakthrough has laid a solid foundation for the application of carbon / carbon composite materials in a wider range of fields and opened up a broader prospect.

[0134] In response to problem ②, the present invention innovatively proposes a preform structure, the remarkable features of which include large axial extension capability, high freedom of design of internal structure, unique three-dimensional integrated structure, compact structure and flexible adjustment of fiber content, and balanced performance between static and dynamic performance. The uniqueness of this preform structure is that each fiber inside it forms a dense braided node in the contour space of the preform by buckling and interlocking. This structure enables each fiber to continuously and completely penetrate the entire preform size space from the outside, not only evenly distributed in the three main directions of XYZ, but also covering other sub-directions. This design cleverly utilizes the omnidirectional distribution characteristics of fibers in space, effectively inhibits the propagation of crack defects inside and on the surface of the composite material, especially at the braided node, which can significantly block the further spread of cracks. Therefore, while exhibiting excellent static performance, the preform structure also maintains good dynamic performance, achieving a balance between the two. In addition, the structure also allows the addition of lining yarn along the axial direction. This design not only further improves the overall mechanical performance indicators of the preform, but also can directionally enhance its static performance in the axial direction, thereby meeting more complex and diverse application requirements.

[0135] In response to problem ③, the present invention first uses a high-carbon material to impregnate the preform to prepare a semi-finished product, and then performs a high-temperature heat treatment at a relatively low temperature. Compared with the high temperature of 2400°C and long treatment time required by the traditional ICVI process, the present invention significantly reduces energy consumption and shortens the heat treatment cycle (can be reduced by 25%-50%), which not only improves production efficiency but also reduces production costs, showing stronger economy and commercial production potential.

[0136] Beneficial effects:

[0137] (1) The three-dimensional braided carbon fiber preform of the present invention can realize dual degrees of freedom design of the external contour and internal structure, which provides a preparation basis for highly customized performance and structure of electrode materials. The external contour can be adapted to a wide range, and the performance distribution inside the same material can be freely designed to a high degree.

[0138] (2) The introduction of a three-dimensional overall structure gives the electrode material excellent comprehensive mechanical properties (including static properties such as bending resistance, shear resistance, and compression resistance, and dynamic properties such as impact resistance and fatigue resistance). It can prevent the expansion and contraction problems after the direct combination of carbon fiber and lithium / sodium ions, and can inhibit the large-scale rapid spread of cracks generated when the electrode is under load, thereby improving the service stability of the material and extending its life.

[0139] (3) The layout of the present invention with increasing pores from the inside to the outside not only significantly improves the ion loading capacity of the electrode material, but also ensures that the electrode material can still serve normally when subjected to a certain tolerance complex load, taking into account both the improvement of ion loading capacity and the maintenance of mechanical properties. It further realizes the direct electrode function application without conductive agent, binder, or active material coating, reduces the consumption of rare resources, reduces costs, and is conducive to promoting the dual-carbon green development strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0140] Figure 1 It is a schematic diagram of the semi-finished product continuous processing equipment line of the present invention;

[0141] Figure 2 is a schematic diagram of a carbon / carbon composite material of the present invention;

[0142] Figure 3 A schematic diagram of a structural battery prepared in the present invention;

[0143] Figure 4 is a schematic diagram of a device according to embodiment A6 of the present invention;

[0144] Figure 5 It is a schematic diagram of the weaving-bundling-winding process of the three-dimensional woven carbon fiber preform of the present invention;

[0145] Figure 6 A schematic diagram of a device in which two lining yarn carriers are respectively arranged on two corner wheels of the second layer and the third layer according to embodiment A5 of the present invention;

[0146] Figure 7 is a schematic diagram of a device according to embodiment A3 of the present invention;

[0147] Figure 8 It is a cross-sectional schematic diagram of an unfilled hollow core of a three-dimensional woven carbon fiber preform of the present invention;

[0148] Fig. 9 for Figure 8An axial view of a three-dimensional woven carbon fiber preform shown;

[0149] Fig.10 It is a cross-sectional schematic diagram of a three-dimensional woven carbon fiber preform of the present invention in which only a part of the hollow core is filled;

[0150] Fig.11 It is a cross-sectional schematic diagram of a three-dimensional braided carbon fiber preform of the present invention in which the hollow core is completely filled; Fig.10 , Fig.11 In the figure, the black circle indicates the axial lining yarn, and the size of the black circle indicates the thickness of the lining yarn;

[0151] Fig.12 A diagram showing the motion trajectory of the yarn when the device for preparing a three-dimensional braided carbon fiber preform of the present invention is used;

[0152] Fig.13 The schematic diagram of the angle wheel provided with a circular slide rail and a circular through hole in the preparation device of the three-dimensional woven carbon fiber preform of the present invention; in the figure, the black dot indicates the position of the lining yarn carrier;

[0153] Fig.14 It is a cross-sectional schematic diagram of a lining yarn carrier base containing a circular slide rail in a preparation device for a three-dimensional braided carbon fiber preform of the present invention;

[0154] Fig.15 It is a schematic diagram of a single lining yarn carrier in the preparation device of the three-dimensional braided carbon fiber preform of the present invention; in the figure, the sphere on the thickness surface of the lining yarn carrier represents a ball;

[0155] Fig.16 is a schematic diagram of a device according to embodiment A4 of the present invention;

[0156] Fig.17 A schematic diagram of a device in which four lining yarn carriers are arranged on the corner wheel of the first layer and one lining yarn carrier is arranged on each corner wheel of the second layer and the third layer according to embodiment A5 of the present invention;

[0157] Fig.18 It is a schematic structural diagram of a spindle in a device for preparing a three-dimensional braided carbon fiber preform of the present invention;

[0158] Fig.19 It is a structural schematic diagram of a yarn removal auxiliary frame in a preparation device for a three-dimensional braided carbon fiber preform of the present invention;

[0159] Fig. 20 A braided section of a three-dimensional braided carbon fiber preform of the present invention and an enlarged schematic diagram thereof;

[0160] Fig.21 is a schematic diagram of a device according to embodiment A7 of the present invention;

[0161] Fig. 22is a schematic diagram of a device according to embodiment A2 of the present invention;

[0162] Among them, 1-carbon matrix, 2-three-dimensional woven carbon fiber preform, 3-pores, 4-structural battery negative electrode, 5-structural battery positive electrode, 6-structural battery separator, 7-preparation device of three-dimensional woven carbon fiber preform, 8-preforming device, 9-infiltration and curing integrated forming mold, 10-post-processing device, 11-drawing device, 12-cutting device, 13-semi-finished product, 14-yarn, 15-woven node. DETAILED DESCRIPTION

[0163] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0164] The testing methods of the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0165] Tensile strength and tensile modulus: The tensile properties and tensile modulus of the carbon / carbon composite materials prepared in each example were measured with reference to GB / T 33501-2017 "Test method for tensile properties of carbon / carbon composite materials".

[0166] Bending strength: The bending properties of the carbon / carbon composite materials prepared in each example were measured with reference to GB / T 40398.2-2021 "Test methods for carbon-carbon composite carbon materials Part 2: Bending properties test" standard.

[0167] Hardness: The hardness of the carbon / carbon composite materials prepared in each embodiment was tested by means of a Bruker TI980 nanoindentation tester, using a standard berkvioch indenter test; wherein, the load resolution was 50 nN, the displacement resolution was 0.3 nm, and the loading displacement was 900 nm.

[0168] Example A1

[0169] A preparation device for a three-dimensional braided carbon fiber preform, comprising a chassis, an angle wheel, a dial and a braided yarn carrier;

[0170] The braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod;

[0171] Each braiding yarn carrier has a matching braiding yarn spindle (such as Fig.18 as shown) and the braiding yarn unwinding auxiliary frame (as shown Fig.19 As shown), the ceramic eyes on the braiding yarn unwinding auxiliary frame are made of aluminum oxide or titanium oxide;

[0172] There are multiple numbers of angle wheels, dials, and braided yarn carrier bases, each angle wheel has a matching angle wheel drive motor, and each dial has a matching dial drive motor;

[0173] The corner wheel is a 6-cut circular plate;

[0174] The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained;

[0175] Each of the cutouts of the 6-cut circular plate is filled with a braided yarn carrier base;

[0176] The dial is a 2-cut circular plate;

[0177] The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts;

[0178] The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same;

[0179] All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6×(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer;

[0180] Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time;

[0181] A metal bunching ring, a pair of rollers and a winding wheel are arranged above the braiding yarn carrier. The metal bunching ring is located below the pair of rollers and is grounded, and the winding wheel is located above the pair of rollers.

[0182] Example A2

[0183] A preparation device for a three-dimensional woven carbon fiber preform is basically the same as Example A1, except that: at least one corner wheel is provided with a lining yarn carrier located at the center of the corner wheel; the lining yarn carrier includes a lining yarn carrier base and a lining yarn carrier straight rod, each lining yarn carrier has a matching lining yarn spindle and a lining yarn withdrawal auxiliary frame, and the material of the porcelain eye on the lining yarn withdrawal auxiliary frame is aluminum oxide or titanium oxide.

[0184] Example A3

[0185] A preparation device for a three-dimensional woven carbon fiber preform is basically the same as that in Embodiment A1, except that: at least one corner wheel is provided with a lining yarn carrier greater than 1 and located at the center of the corner wheel;

[0186] like Fig.15 As shown, the lining yarn carrier comprises a lining yarn carrier base and a lining yarn carrier straight rod. The lining yarn carrier base is circular in shape, and balls are embedded on the circumferential surface and the bottom surface.

[0187] Each lining yarn carrier has a matching lining yarn spindle and a lining yarn unwinding auxiliary frame. The ceramic eye on the lining yarn unwinding auxiliary frame is made of aluminum oxide or titanium oxide.

[0188] like Fig.13 As shown, the corner wheel provided with the lining yarn carrier is provided with a circular slide rail and a circular through hole, and the circular through hole is located directly above the circular slide rail;

[0189] The center of the circular slide rail is located on the central axis of the angle wheel, and the lining yarn carrier base is slidably connected with the circular slide rail;

[0190] The circular through hole is used for the straight rod of the lining yarn carrier to pass through. The diameter of the circular through hole is smaller than the width of the circular slide rail. The cross-section diagram of the lining yarn carrier base and the circular slide rail is as follows: Fig.14 shown.

[0191] Example A4

[0192] A preparation device for a three-dimensional braided carbon fiber preform is basically the same as that in Example A1, except that:

[0193] When n>2, for the cuts in each 6-cut circular plate of the nth layer that are not opposite to other cuts, the braided yarn carrier base in each cut is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braided yarn carrier base;

[0194] When n=2, in each 6-notch circular plate of the nth layer, the number of notches that are not opposite to other notches is 3, which are respectively recorded as notch a, notch b and notch c, and notch b is located between notch a and notch c;

[0195] The braided yarn carrier base in the cutout a is filled with one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled with another braided yarn carrier base;

[0196] The braided yarn carrier base in the cutout b is filled with one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled with another braided yarn carrier base;

[0197] The braiding yarn carrier base in the cutout c fills one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled by the other braiding yarn carrier base.

[0198] Example A5

[0199] A preparation device for a three-dimensional braided carbon fiber preform, which is basically the same as that in Example A3, except that: n>2;

[0200] For the cuts in each 6-cut circular plate of the nth layer that are not opposite to other cuts, the knitting yarn carrier base in each cut is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base.

[0201] Example A6

[0202] A preparation device for a three-dimensional braided carbon fiber preform is basically the same as that in Example A3, except that: n=2;

[0203] In each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c;

[0204] The braiding yarn carrier base in the cutout a is filled with one cutout of a two-cutout circular plate, and the other cutout of the two-cutout circular plate is filled with another braiding yarn carrier base, and the two-cutout circular plate is marked as dial a;

[0205] The braiding yarn carrier base in the incision b is filled with one incision of a two-incision circular plate, and the other incision of the two-incision circular plate is filled with another braiding yarn carrier base, and the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-incision circular plate is recorded as dial b;

[0206] The braiding yarn carrier base in the cut c is filled with one cut of a two-cut circular plate, and the other cut of the two-cut circular plate is filled with another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c.

[0207] Example A7

[0208] A preparation device for a three-dimensional braided carbon fiber preform is basically the same as Example A6, except that: the braided yarn carrier base in the cutout b does not fill one cutout of a two-cutout circular plate.

[0209] Example B1

[0210] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0211] (1) Preparation of raw materials and equipment for three-dimensional woven carbon fiber preforms;

[0212] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0213] Device: A device of Example A1, wherein the number of layers of angle wheels is 2, the number of angle wheels is 7, the number of dials is 12, the number of braiding yarn carrier bases is 42, and the porcelain eyes on the braiding yarn unwinding auxiliary frame are made of alumina;

[0214] (2) First, the yarn is unwound from the standard reel and then wound onto the braiding yarn spindle, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and finally, the yarn on the braiding yarn spindle is passed through the porcelain eye on the side of the braiding yarn unwinding auxiliary frame and then bundled through the metal bundling ring;

[0215] (3) Weaving a three-dimensional woven carbon fiber preform;

[0216] like Figure 5 As shown, after all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a braiding angle of 30° (as shown in FIG. Fig. 20 As shown, the coordinated movement of the dial and the angle wheel will cause the yarn 14 to form a braided node 15), and after the winding is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0217] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0218] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0219] (c) Repeat steps (a) to (b) several times, and the trajectory of the yarn is as follows: Fig.12 As shown;

[0220] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0221] The final three-dimensional woven carbon fiber preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer is connected to the i-1-th layer through 12×(i-3)+18 evenly distributed braided nodes, and i is 2. The axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 2.7kN, and the elongation at break is 3.6%.

[0222] Example B2

[0223] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0224] (1) Prepare yarn and equipment;

[0225] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0226] Device: A device of Example A2, such as Fig. 22 As shown, there are 3 layers of angle wheels, 19 angle wheels, 42 dials, 114 braiding yarn carrier bases, one lining yarn carrier is arranged on each angle wheel, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of alumina, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of alumina;

[0227] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are coaxially assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn unwinding auxiliary frame are coaxially assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn unwinding auxiliary frame and the porcelain eyes on the side of the lining yarn unwinding auxiliary frame, and then bundled through the metal bundling ring;

[0228] (3) Weaving a three-dimensional woven carbon fiber preform;

[0229] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0230] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0231] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0232] (c) Repeat steps (a) to (b) multiple times;

[0233] The ambient temperature in steps (2) to (3) is 25°C and the relative humidity is 70%.

[0234] The final three-dimensional woven carbon fiber preform has a three-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 16.8kN, and the elongation at break is 3.8%.

[0235] Example B3

[0236] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0237] (1) Prepare yarn and equipment;

[0238] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0239] Device: A device of Example A3, such as Figure 7 As shown, there are 3 layers of angle wheels, 19 angle wheels, 42 dials, 114 braiding yarn carrier bases, 4 lining yarn carriers are arranged on each angle wheel, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of titanium oxide, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of titanium oxide;

[0240] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are coaxially assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn unwinding auxiliary frame are coaxially assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn unwinding auxiliary frame and the porcelain eyes on the side of the lining yarn unwinding auxiliary frame, and then bundled through the metal bundling ring;

[0241] (3) Weaving a three-dimensional woven carbon fiber preform;

[0242] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0243] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0244] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0245] (c) Repeat steps (a) to (b) multiple times;

[0246] The ambient temperature in steps (2) to (3) is 20°C and the relative humidity is 60%.

[0247] The final three-dimensional woven carbon fiber preform has a three-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer is connected to the i-1-th layer by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 21.8kN, and the elongation at break is 3.3%.

[0248] Example B4

[0249] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0250] (1) Prepare yarn and equipment;

[0251] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0252] Device: A device of Example A4, such as Fig.16 As shown, there are 3 layers of angle wheels, 19 angle wheels, 72 dials, 144 braiding yarn carrier bases, and the porcelain eyes on the braiding yarn unwinding auxiliary frame are made of alumina;

[0253] (2) First, the yarn is wound onto the braiding yarn spindle, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and finally, the yarn on the braiding yarn spindle is passed through the porcelain eye on the side of the braiding yarn unwinding auxiliary frame and then bundled through the metal bundling ring;

[0254] (3) Weaving a three-dimensional woven carbon fiber preform;

[0255] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0256] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0257] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0258] (c) Repeat steps (a) to (b) multiple times;

[0259] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0260] The final three-dimensional braided carbon fiber preform (whose cross section is as follows Figure 8 As shown, its axial surface is Fig. 9 As shown in FIG. 1 ), the three-layer structure is shown. The layers are numbered from 1 from the inside to the outside. The i-th layer is connected to the i-1-th layer by 12×(i-3)+18 evenly distributed braided nodes, 2≤i≤3. The axial tensile breaking strength of the three-dimensional braided carbon fiber preform is 11.6 kN, and the elongation at break is 4.0%.

[0261] Example B5

[0262] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0263] (1) Prepare yarn and equipment;

[0264] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0265] Device: A device of Example A5, such as Figure 6 As shown, there are 3 layers of angle wheels, 19 angle wheels, 72 dials, 144 braiding yarn carrier bases, 2 lining yarn carriers are respectively arranged on the 2 angle wheels of the 2nd layer and the 2 angle wheels of the 3rd layer, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of titanium oxide, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of titanium oxide;

[0266] (2) First, the yarn is wound onto the braiding yarn spindle and the backing yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn backing auxiliary frame are coaxially assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the backing yarn spindle and the backing yarn backing auxiliary frame are coaxially assembled onto the backing yarn carrier straight rod of the matching backing yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the backing yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn backing auxiliary frame and the porcelain eyes on the side of the backing yarn backing auxiliary frame, and then bundled through the metal bundling ring;

[0267] (3) Weaving a three-dimensional woven carbon fiber preform;

[0268] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0269] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0270] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0271] (c) Repeat steps (a) to (b) multiple times;

[0272] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0273] The final three-dimensional braided carbon fiber preform (whose cross section is as follows Fig.10 As shown in the figure, it has a three-layer structure, each layer is numbered from 1 from the inside to the outside, the i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes, and between the i-th layer and the i-1-th layer, some holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional braided carbon fiber preform is 13.1kN, and the elongation at break is 3.9%.

[0274] Example B6

[0275] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0276] (1) Prepare yarn and equipment;

[0277] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0278] Device: A device of Example A6, such as Figure 4 As shown, the number of corner wheels is 2, the number of corner wheels is 7, the number of dials is 30, the number of braiding yarn carrier bases is 60, one lining yarn carrier is arranged on each corner wheel, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of titanium oxide, and the porcelain eye on the lining yarn withdrawal auxiliary frame is made of titanium oxide;

[0279] (2) First, control the weaving yarn spindles and lining yarn spindles of the other weaving yarn carriers except the weaving yarn carrier b to wind the yarn around them, then assemble the weaving yarn spindles and the weaving yarn withdrawal auxiliary frame with the yarn wrapped around them concentrically to the weaving yarn carrier straight rod of the matching weaving yarn carrier, and at the same time, assemble the lining yarn spindles and the lining yarn withdrawal auxiliary frame concentrically to the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, pass the yarn on the weaving yarn spindle and the yarn on the lining yarn spindle through the porcelain eyes on the side of the weaving yarn withdrawal auxiliary frame and the porcelain eyes on the side of the lining yarn withdrawal auxiliary frame respectively, and then bundle them through the metal bundling ring;

[0280] (3) Weaving a three-dimensional woven carbon fiber preform;

[0281] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0282] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0283] (b) Controlling the dials other than the dials b and c to rotate 180° clockwise in the same direction under the drive of the dial drive motor, and controlling the dial c to rotate 180° counterclockwise under the drive of the dial drive motor;

[0284] (c) Repeat steps (a) to (b) multiple times;

[0285] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0286] The final three-dimensional woven carbon fiber preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, and i is 2. The axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 3.6kN, and the elongation at break is 3.2%.

[0287] Example B7

[0288] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0289] (1) Prepare yarn and equipment;

[0290] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness specification is 6k;

[0291] Device: A device of Example A7, such as Fig.21 As shown, the number of corner wheels is 2, the number of corner wheels is 7, the number of dials is 24, the number of braiding yarn carrier bases is 54, 3 lining yarn carriers are arranged on each corner wheel, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of titanium oxide, and the material of the porcelain eye on the lining yarn withdrawal auxiliary frame is titanium oxide;

[0292] (2) First, control the weaving yarn spindles and lining yarn spindles of the other weaving yarn carriers except the weaving yarn carrier b to wind the yarn around them, then assemble the weaving yarn spindles and the weaving yarn withdrawal auxiliary frame with the yarn wrapped around them concentrically to the weaving yarn carrier straight rod of the matching weaving yarn carrier, and at the same time, assemble the lining yarn spindles and the lining yarn withdrawal auxiliary frame concentrically to the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, pass the yarn on the weaving yarn spindle and the yarn on the lining yarn spindle through the porcelain eyes on the side of the weaving yarn withdrawal auxiliary frame and the porcelain eyes on the side of the lining yarn withdrawal auxiliary frame respectively, and then bundle them through the metal bundling ring;

[0293] (3) Weaving a three-dimensional woven carbon fiber preform;

[0294] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0295] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0296] (b) the dials other than the dial c are controlled to rotate 180° clockwise in the same direction under the drive of the dial drive motor, and the dial c is controlled to rotate 180° counterclockwise under the drive of the dial drive motor;

[0297] (c) Repeat steps (a) to (b) multiple times;

[0298] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0299] The final three-dimensional woven carbon fiber preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, and i is 2. The axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 4.7kN, and the elongation at break is 3.3%.

[0300] Example B8

[0301] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0302] (1) Prepare yarn and equipment;

[0303] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness is 12k;

[0304] Device: A device of Example A4, wherein the number of the angle wheels is 7, the number of the dials is 30, the number of the braiding yarn carrier bases is 60, the number of the angle wheels is 2, and the porcelain eyes on the braiding yarn unwinding auxiliary frame are made of titanium oxide;

[0305] (2) First, the yarn is unwound from the standard reel and then wound onto the braiding yarn spindle, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are concentrically assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and finally, the yarn on the braiding yarn spindle is passed through the porcelain eye on the side of the braiding yarn unwinding auxiliary frame and then bundled through the metal bundling ring;

[0306] (3) Weaving a three-dimensional woven carbon fiber preform;

[0307] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0308] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0309] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0310] (c) Repeat steps (a) to (b) multiple times;

[0311] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0312] The final three-dimensional woven carbon fiber preform has a two-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, the holes between all the braided nodes are unfilled, and i is 2. The axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 3.0 kN, and the elongation at break is 3.4%.

[0313] Example B9

[0314] A method for preparing a three-dimensional braided carbon fiber preform, comprising the following steps:

[0315] (1) Prepare yarn and equipment;

[0316] Yarn: Carbon fiber yarn, tensile strength is 4900MPa, elongation at break is 1.8%, thickness is 12k;

[0317] Device: A device of Example A5, such as Fig.17 As shown, the number of angle wheels is 19, the number of dials is 72, the number of braiding yarn carrier bases is 144, the number of angle wheels is 3 layers, 4 lining yarn carriers are arranged on 1 angle wheel of the first layer, 1 lining yarn carrier is arranged on 6 angle wheels of the second layer and 12 angle wheels of the third layer respectively, the porcelain eye on the braiding yarn withdrawal auxiliary frame is made of alumina material, and the material of the porcelain eye on the lining yarn withdrawal auxiliary frame is alumina material;

[0318] (2) First, the yarn is wound onto the braiding yarn spindle and the lining yarn spindle respectively, and then the braiding yarn spindle and the braiding yarn unwinding auxiliary frame are coaxially assembled onto the braiding yarn carrier straight rod of the matching braiding yarn carrier, and at the same time, the lining yarn spindle and the lining yarn unwinding auxiliary frame are coaxially assembled onto the lining yarn carrier straight rod of the matching lining yarn carrier, and finally, the yarn on the braiding yarn spindle and the yarn on the lining yarn spindle are respectively passed through the porcelain eyes on the side of the braiding yarn unwinding auxiliary frame and the porcelain eyes on the side of the lining yarn unwinding auxiliary frame, and then bundled through the metal bundling ring;

[0319] (3) Weaving a three-dimensional woven carbon fiber preform;

[0320] After all the yarns are bundled, they first pass through a pair of rollers and then are reeled in by a continuously rotating reel. During the reeling process, the angle wheel and the dial are controlled to rotate so that the braiding machine can weave at a 30° braiding angle. After the reeling is completed, a three-dimensional braided carbon fiber preform is obtained. The control process is as follows:

[0321] (a) Control all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel drive motor;

[0322] (b) controlling all the dials to rotate 180° clockwise in the same direction under the drive of the dial drive motor;

[0323] (c) Repeat steps (a) to (b) multiple times;

[0324] The ambient temperature in steps (2) to (3) is 23°C and the relative humidity is 68%.

[0325] The final three-dimensional braided carbon fiber preform (whose cross section is as follows Fig.11As shown in the figure, it has a three-layer structure, each layer is numbered from 1 from the inside to the outside, the i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes, and between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional braided carbon fiber preform is 18.1kN, and the elongation at break is 3.4%.

[0326] Example B10

[0327] A method for preparing a three-dimensional woven carbon fiber preform is basically the same as that of Example B9, except that: the control process of step (3) when weaving the three-dimensional woven carbon fiber preform is as follows: (a) controlling all corner wheels to rotate 60° counterclockwise in the same direction under the drive of the corner wheel driving motor; (b) controlling the dial intervals between the corner wheels of the i-th layer to remain fixed, the dial intervals between the corner wheels of the i-1th layer and the corner wheels of the i-th layer to remain fixed, and the other dials to rotate 180° clockwise in the same direction under the drive of the dial driving motor; (c) repeating steps (a) to (b) multiple times.

[0328] The final three-dimensional woven carbon fiber preform has a three-layer structure. The layers are numbered from 1 from the inside to the outside. The i-th layer and the i-1-th layer are connected by 12×(i-3)+18 evenly distributed braided nodes. Between the i-th layer and the i-1-th layer, all the holes between the braided nodes are filled, 2≤i≤3; the axial tensile breaking strength of the three-dimensional woven carbon fiber preform is 18.6kN, and the elongation at break is 3.2%.

[0329] Example C1

[0330] A method for preparing a carbon / carbon composite material, comprising the following steps:

[0331] (1) Preparation of raw materials and equipment;

[0332] High carbon content: phenolic resin, solid content is 65%, viscosity is 20cps at 25℃, residual carbon content is 50%;

[0333] Three-dimensional braided carbon fiber preform: prepared in Example B3;

[0334] Equipment for preparing carbon / carbon composite materials, including semi-finished product continuous processing equipment, carbonization equipment, plasma treatment equipment; such as Figure 1 As shown, the semi-finished product continuous processing equipment includes a high-carbon material injection machine and a preparation device 7 of a three-dimensional woven carbon fiber preform arranged in sequence along the conveying direction, a preforming device 8, an impregnation and curing integrated molding mold 9, a post-processing device 10, a drafting device 11, and a cutting device 12;

[0335] (2) The three-dimensional woven carbon fiber preform is impregnated with a high-carbon material by vacuum injection infiltration technology, and then cured for 3 hours at a temperature of 190° C. and a pressure of 0.1 MPa, and then post-processed by a post-processing device, and then stretched by a stretching device 11, and finally cut by a cutting device 12 to obtain a semi-finished product 13; wherein the injection pressure during impregnation is 0.1 bar, and the volume ratio of the high-carbon material to the three-dimensional woven carbon fiber preform is 35:62.5;

[0336] (3) The semi-finished product obtained in step (2) is subjected to a first-stage carbon treatment, a second-stage carbon treatment, a plasma treatment, and a third-stage carbon treatment in sequence to obtain a carbon / carbon composite material; wherein the temperature of the first-stage carbon treatment is 900°C and the time is 5 hours, the temperature of the second-stage carbon treatment is 100°C higher than the temperature of the first-stage carbon treatment, the time of the second-stage carbon treatment is 1 hour shorter than the time of the first-stage carbon treatment, the temperature of the third-stage carbon treatment is 200°C higher than the temperature of the second-stage carbon treatment, the time of the third-stage carbon treatment is 2 hours shorter than the time of the second-stage carbon treatment, the plasma treatment uses a plasma emitter, the power of the plasma emitter is 500W and the distance from the surface of the semi-finished product is 3 cm, and the time of the plasma treatment is 60 minutes.

[0337] The carbon / carbon composite material finally obtained is Figure 2 As shown, it is mainly composed of a carbon matrix 1 and a three-dimensional woven carbon fiber preform 2 located therein, and has a multi-layer integrated structure as a whole, the inner layer is dense, the middle layer and the outer layer are porous, and the pores 3 are mainly nano-scale pores, the number of pores 3 in the outer layer is greater than that in the middle layer, the volume proportion of the inner layer of the carbon / carbon composite material is 75%, the volume proportion of the middle layer is 10%, and the volume proportion of the outer layer is 15%, and the volume proportion of each layer is the percentage of the sum of the solid volume and the volume of the pores 3 of the layer to the sum of the solid volume and the volume of the pores 3 of the carbon / carbon composite material;

[0338] The overall porosity of the carbon / carbon composite is 2.5%, the pore volume of the outer layer accounts for 75% of the overall pore volume of the carbon / carbon composite, the nanoscale pore volume accounts for 70% of all pore volumes, and the average pore size of the nanoscale pores is 55nm;

[0339] The density of carbon / carbon composite material is 1.1g / cm 3 , tensile strength is 800MPa, tensile modulus is 400GPa, flexural strength is 700MPa, and hardness is 60GPa.

[0340] An application of a carbon / carbon composite material, using the carbon / carbon composite material prepared above to prepare a structural battery, specifically: Figure 3As shown, the carbon / carbon composite material prepared as above is used as the negative electrode 4 of the structural battery, the carbon / carbon composite material after lithium / sodium ion attachment treatment is used as the positive electrode 5 of the structural battery, and a glass fiber separation membrane is used as the structural battery separator 6.

[0341] Example C2

[0342] A method for preparing a carbon / carbon composite material, comprising the following steps:

[0343] (1) Preparation of raw materials and equipment;

[0344] High carbon content material: phenolic resin, solid content is 60%, viscosity is 200cps at 25℃, residual carbon content is 45%;

[0345] Three-dimensional woven carbon fiber preform: prepared in Example B2;

[0346] Devices used to prepare carbon / carbon composite materials, including semi-finished product continuous processing equipment, carbonization equipment, and plasma treatment equipment; semi-finished product continuous processing equipment includes a high-carbon material injection machine and a preparation device for three-dimensional woven carbon fiber preforms arranged in sequence along the conveying direction, a preforming device, an infiltration and curing integrated molding mold, a post-processing device, a drafting device, and a cutting device;

[0347] (2) A three-dimensional woven carbon fiber preform is impregnated with a high-carbon material by vacuum injection infiltration technology, and then cured for 2 hours at a temperature of 130°C and a pressure of 1.3 MPa, and then post-processed by a post-processing device, and then stretched by a stretching device, and finally cut by a cutting device to obtain a semi-finished product; wherein the injection pressure during impregnation is 0.6 bar, and the volume ratio of the high-carbon material to the three-dimensional woven carbon fiber preform is 39:56;

[0348] (3) The semi-finished product obtained in step (2) is subjected to a first-stage carbon treatment, a second-stage carbon treatment, a plasma treatment, and a third-stage carbon treatment in sequence to obtain a carbon / carbon composite material; wherein the temperature of the first-stage carbon treatment is 1000°C and the time is 8 hours, the temperature of the second-stage carbon treatment is 400°C higher than the temperature of the first-stage carbon treatment, the time of the second-stage carbon treatment is 2 hours shorter than the time of the first-stage carbon treatment, the temperature of the third-stage carbon treatment is 360°C higher than the temperature of the second-stage carbon treatment, the time of the third-stage carbon treatment is 5 hours shorter than the time of the second-stage carbon treatment, the plasma treatment uses a plasma emitter, the power of the plasma emitter is 700W and the distance from the surface of the semi-finished product is 5 cm, and the time of the plasma treatment is 40 minutes.

[0349] The finally prepared carbon / carbon composite material is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein, and has a multi-layer integrated structure as a whole, wherein the inner layer is dense, the middle layer and the outer layer are porous and the pores are mainly nano-scale pores, the number of pores in the outer layer is greater than that in the middle layer, the volume proportion of the inner layer of the carbon / carbon composite material is 73%, the volume proportion of the middle layer is 14%, and the volume proportion of the outer layer is 13%, and the volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material;

[0350] The overall porosity of the carbon / carbon composite material is 5%, the pore volume of the outer layer accounts for 60% of the overall pore volume of the carbon / carbon composite material, the nanoscale pore volume accounts for 65% of all pore volumes, and the average pore size of the nanoscale pores is 50nm;

[0351] The density of carbon / carbon composite material is 1.0g / cm 3 , tensile strength is 700MPa, tensile modulus is 350GPa, flexural strength is 500MPa, and hardness is 40GPa.

[0352] An application of a carbon / carbon composite material, using the carbon / carbon composite material prepared above to prepare a structural battery, specifically: using the carbon / carbon composite material prepared above as the negative electrode of the structural battery, using the carbon / carbon composite material after lithium / sodium ion attachment treatment as the positive electrode of the structural battery, and using a glass fiber separation membrane as a structural battery separator.

[0353] Example C3

[0354] A method for preparing a carbon / carbon composite material, comprising the following steps:

[0355] (1) Preparation of raw materials and equipment;

[0356] High carbon content material: phenolic resin, solid content is 50%, viscosity is 2000cps at 25℃, residual carbon content is 35%;

[0357] Three-dimensional woven carbon fiber preform: prepared in Example B1;

[0358] Devices used to prepare carbon / carbon composite materials, including semi-finished product continuous processing equipment, carbonization equipment, and plasma treatment equipment; semi-finished product continuous processing equipment includes a high-carbon material injection machine and a preparation device for three-dimensional woven carbon fiber preforms arranged in sequence along the conveying direction, a preforming device, an infiltration and curing integrated molding mold, a post-processing device, a drafting device, and a cutting device;

[0359] (2) A three-dimensional woven carbon fiber preform is impregnated with a high-carbon material by vacuum injection infiltration technology, and then cured for 0.2 h at a temperature of 80°C and a pressure of 2 MPa, and then post-processed by a post-processing device, and then stretched by a stretching device, and finally cut by a cutting device to obtain a semi-finished product; wherein the injection pressure during impregnation is 1 bar, and the volume ratio of the high-carbon material to the three-dimensional woven carbon fiber preform is 46:47;

[0360] (3) The semi-finished product obtained in step (2) is subjected to a first-stage carbon treatment, a second-stage carbon treatment, a plasma treatment, and a third-stage carbon treatment in sequence to obtain a carbon / carbon composite material; wherein the temperature of the first-stage carbon treatment is 1100°C and the time is 10 hours; the temperature of the second-stage carbon treatment is 230°C higher than the temperature of the first-stage carbon treatment; the time of the second-stage carbon treatment is 3 hours shorter than the time of the first-stage carbon treatment; the temperature of the third-stage carbon treatment is 500°C higher than the temperature of the second-stage carbon treatment; the time of the third-stage carbon treatment is 7 hours shorter than the time of the second-stage carbon treatment; the plasma treatment uses a plasma emitter; the power of the plasma emitter is 900 W and the distance from the surface of the semi-finished product is 6 cm; the time of the plasma treatment is 10 minutes.

[0361] The finally prepared carbon / carbon composite material is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein, and has a multi-layer integrated structure as a whole, wherein the inner layer is dense, the middle layer and the outer layer are porous and the pores are mainly nano-scale pores, the number of pores in the outer layer is greater than that in the middle layer, the volume proportion of the inner layer of the carbon / carbon composite material is 70%, the volume proportion of the middle layer is 15%, and the volume proportion of the outer layer is 15%, and the volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material;

[0362] The overall porosity of the carbon / carbon composite material is 7%, the pore volume of the outer layer accounts for 65% of the overall pore volume of the carbon / carbon composite material, the nanoscale pore volume accounts for 60% of all pore volumes, and the average pore size of the nanoscale pores is 53nm;

[0363] The density of carbon / carbon composite material is 0.8g / cm 3 , tensile strength is 600MPa, tensile modulus is 250GPa, flexural strength is 450MPa, and hardness is 10GPa.

[0364] An application of a carbon / carbon composite material, using the carbon / carbon composite material prepared above to prepare a structural battery, specifically: using the carbon / carbon composite material prepared above as the negative electrode of the structural battery, using the carbon / carbon composite material after lithium / sodium ion attachment treatment as the positive electrode of the structural battery, and using a glass fiber separation membrane as a structural battery separator.

[0365] Example D1

[0366] A method for preparing a carbon / carbon composite material, comprising the following steps:

[0367] (1) Preparation of raw materials;

[0368] High carbon content: phenolic resin, solid content is 65%, viscosity is 20cps at 25℃, residual carbon content is 50%;

[0369] Three-dimensional braided carbon fiber preform: prepared in Example B5;

[0370] Carbon aerogel powder: Prepare an acidic strong oxidizing activator with high-grade pure sulfuric acid, analytical-grade ammonium persulfate, and high-grade pure nitric acid in a mass ratio of 1:3:1, add 300 mL of deionized water and mix well, then immerse the carbon aerogel powder in the prepared strong oxidizing activator and treat it with ultrasonic vibration at 80°C for 1h, then filter out the carbon aerogel powder with analytical filter paper, neutralize and wash it with sodium hydroxide aqueous solution (concentration of 5wt%) 4 times, wash it with deionized water to pH 7, and finally dry the wet carbon aerogel in an oven at 85°C;

[0371] (2) The three-dimensional woven carbon fiber preform is impregnated with a liquid high-carbon material by vacuum injection infiltration technology, and then cured for 3 hours at a temperature of 190°C and a pressure of 2 MPa to obtain a semi-finished product a; wherein the injection pressure during impregnation is 0.1 bar;

[0372] (3) The semi-finished product a is subjected to a first-stage carbon treatment and a second-stage carbon treatment in sequence to obtain a semi-finished product b; wherein the temperature of the first-stage carbon treatment is 1100°C and the time is 5 hours; the temperature of the second-stage carbon treatment is 400°C higher than the temperature of the first-stage carbon treatment, and the time of the second-stage carbon treatment is 3 hours shorter than the time of the first-stage carbon treatment;

[0373] (4) The semi-finished product b was impregnated into a mixture of carbon aerogel powder and liquid high-carbon material in a volume ratio of 3:100 by vacuum injection infiltration technology, and stored in a reactor. The temperature of the reactor was maintained at 75°C. The reactor was gradually pressurized to 2 MPa and maintained at the pressure for 4 hours. Four cycles were repeated to obtain a semi-finished product c. The injection pressure during impregnation was 0.1 bar.

[0374] The volume of the high-carbon-content material in step (2) is 54% of the total volume of the high-carbon-content material in step (2) and step (4), and the ratio of the total volume of the high-carbon-content material in step (2) and step (4) to the volume of the three-dimensional woven carbon fiber preform is 35.5:62;

[0375] (5) The semi-finished product c is subjected to a third-stage carbon treatment to obtain a carbon / carbon composite material; wherein the temperature of the third-stage carbon treatment is 500°C higher than the temperature of the second-stage carbon treatment, and the time of the third-stage carbon treatment is 7 hours shorter than the time of the second-stage carbon treatment.

[0376] The carbon / carbon composite material finally obtained is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein, and has a multi-layer integrated structure as a whole, with a dense inner layer, a porous middle layer and an outer layer, and the pores are mainly nano-scale pores, and the number of pores in the outer layer is greater than that in the middle layer;

[0377] The volume proportion of the inner layer of the carbon / carbon composite material is 75%, the volume proportion of the middle layer is 10%, and the volume proportion of the outer layer is 15%. The volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material.

[0378] The overall porosity of the carbon / carbon composite is 2.5%, the pore volume of the outer layer accounts for 73% of the overall pore volume of the carbon / carbon composite, the nanoscale pore volume accounts for 70% of all pore volumes, and the average pore size of the nanoscale pores is 53nm;

[0379] The density of carbon / carbon composite material is 1.1g / cm 3 , tensile strength is 780MPa, tensile modulus is 380GPa, flexural strength is 500MPa, and hardness is 55GPa.

[0380] An application of a carbon / carbon composite material, using the carbon / carbon composite material prepared above to prepare a structural battery, specifically: using the carbon / carbon composite material prepared above as the negative electrode of the structural battery, using the carbon / carbon composite material after lithium / sodium ion attachment treatment as the positive electrode of the structural battery, and using a glass fiber separation membrane as a structural battery separator.

[0381] Example D2

[0382] A method for preparing a carbon / carbon composite material, comprising the following steps:

[0383] (1) Preparation of raw materials;

[0384] High carbon content material: phenolic resin, solid content is 60%, viscosity is 200cps at 25℃, residual carbon content is 45%;

[0385] Three-dimensional woven carbon fiber preform: prepared in Example B4;

[0386] Carbon aerogel powder: Prepare an acidic strong oxidizing activator with high-grade pure sulfuric acid, analytical-grade ammonium persulfate, and high-grade pure nitric acid in a mass ratio of 1:3:1, add 300 mL of deionized water and mix well, then immerse the carbon aerogel powder in the prepared strong oxidizing activator and treat it with ultrasonic vibration at 80°C for 1h, then filter out the carbon aerogel powder with analytical filter paper, neutralize and wash it with sodium hydroxide aqueous solution (concentration of 5wt%) 4 times, wash it with deionized water to pH 7, and finally dry the wet carbon aerogel in an oven at 85°C;

[0387] (2) The three-dimensional woven carbon fiber preform is impregnated with a liquid high-carbon material by vacuum injection infiltration technology, and then cured for 2 hours at a temperature of 120°C and a pressure of 1 MPa to obtain a semi-finished product a; wherein the injection pressure during impregnation is 0.6 bar;

[0388] (3) The semi-finished product a is subjected to a first-stage carbon treatment and a second-stage carbon treatment in sequence to obtain a semi-finished product b; wherein the temperature of the first-stage carbon treatment is 900°C and the time is 8 hours; the temperature of the second-stage carbon treatment is 260°C higher than the temperature of the first-stage carbon treatment, and the time of the second-stage carbon treatment is 2 hours shorter than the time of the first-stage carbon treatment;

[0389] (4) The semi-finished product b was impregnated into a mixture of carbon aerogel powder and liquid high-carbon material in a volume ratio of 6:100 by vacuum injection infiltration technology, and stored in a reactor. The temperature of the reactor was maintained at 60°C. The reactor was gradually pressurized to 3 MPa and maintained at the pressure for 3 h. The semi-finished product c was obtained after 5 cycles. The injection pressure during impregnation was 0.6 bar.

[0390] The volume of the high-carbon-content material in step (2) is 60% of the total volume of the high-carbon-content material in step (2) and step (4), and the ratio of the total volume of the high-carbon-content material in step (2) and step (4) to the volume of the three-dimensional woven carbon fiber preform is 38.5:57.5;

[0391] (5) The semi-finished product c is subjected to a third-stage carbon treatment to obtain a carbon / carbon composite material; wherein the temperature of the third-stage carbon treatment is 300°C higher than the temperature of the second-stage carbon treatment, and the time of the third-stage carbon treatment is 5 hours shorter than the time of the second-stage carbon treatment.

[0392] The carbon / carbon composite material finally obtained is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein, and has a multi-layer integrated structure as a whole, with a dense inner layer, a porous middle layer and an outer layer, and the pores are mainly nano-scale pores, and the number of pores in the outer layer is greater than that in the middle layer;

[0393] The volume proportion of the inner layer of the carbon / carbon composite material is 73%, the volume proportion of the middle layer is 14%, and the volume proportion of the outer layer is 13%. The volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material.

[0394] The overall porosity of the carbon / carbon composite is 4%, the pore volume of the outer layer accounts for 65% of the overall pore volume of the carbon / carbon composite, the nanoscale pore volume accounts for 63% of all pore volumes, and the average pore size of the nanoscale pores is 57nm;

[0395] The density of carbon / carbon composite material is 0.8g / cm 3 , tensile strength is 690MPa, tensile modulus is 340GPa, flexural strength is 490MPa, and hardness is 43GPa.

[0396] An application of a carbon / carbon composite material, using the carbon / carbon composite material prepared above to prepare a structural battery, specifically: using the carbon / carbon composite material prepared above as the negative electrode of the structural battery, using the carbon / carbon composite material after lithium / sodium ion attachment treatment as the positive electrode of the structural battery, and using a glass fiber separation membrane as a structural battery separator.

[0397] Example D3

[0398] A method for preparing a carbon / carbon composite material, comprising the following steps:

[0399] (1) Preparation of raw materials;

[0400] High carbon content material: phenolic resin, solid content is 50%, viscosity is 2000cps at 25℃, residual carbon content is 35%;

[0401] Three-dimensional woven carbon fiber preform: prepared in Example B7;

[0402] Carbon aerogel powder: Prepare an acidic strong oxidizing activator with high-grade pure sulfuric acid, analytical-grade ammonium persulfate, and high-grade pure nitric acid in a mass ratio of 1:3:1, add 300 mL of deionized water and mix well, then immerse the carbon aerogel powder in the prepared strong oxidizing activator and treat it with ultrasonic vibration at 80°C for 1h, then filter out the carbon aerogel powder with analytical filter paper, neutralize and wash it with sodium hydroxide aqueous solution (concentration of 5wt%) 4 times, wash it with deionized water to pH 7, and finally dry the wet carbon aerogel in an oven at 85°C;

[0403] (2) The three-dimensional woven carbon fiber preform is impregnated with a liquid high-carbon material by vacuum injection infiltration technology, and then cured for 0.2 h at a temperature of 80° C. and a pressure of 0.1 MPa to obtain a semi-finished product a; wherein the injection pressure during impregnation is 1 bar;

[0404] (3) The semi-finished product a is subjected to a first-stage carbon treatment and a second-stage carbon treatment in sequence to obtain a semi-finished product b; wherein the temperature of the first-stage carbon treatment is 1000°C and the time is 10 hours; the temperature of the second-stage carbon treatment is 100°C higher than the temperature of the first-stage carbon treatment, and the time of the second-stage carbon treatment is 1 hour shorter than the time of the first-stage carbon treatment;

[0405] (4) The semi-finished product b was impregnated into a mixture of carbon aerogel powder and liquid high-carbon material in a volume ratio of 9:100 by vacuum injection infiltration technology, and stored in a reactor. The temperature of the reactor was maintained at 45°C. The reactor was gradually pressurized to 5 MPa and maintained at the pressure for 2 h. Six cycles were repeated to obtain a semi-finished product c. The injection pressure during impregnation was 1 bar.

[0406] The volume of the high-carbon-content material in step (2) is 71% of the total volume of the high-carbon-content material in step (2) and step (4), and the ratio of the total volume of the high-carbon-content material in step (2) and step (4) to the volume of the three-dimensional woven carbon fiber preform is 45:49;

[0407] (5) The semi-finished product c is subjected to a third-stage carbon treatment to obtain a carbon / carbon composite material; wherein the temperature of the third-stage carbon treatment is 200°C higher than the temperature of the second-stage carbon treatment, and the time of the third-stage carbon treatment is 2h shorter than the time of the second-stage carbon treatment.

[0408] The carbon / carbon composite material finally obtained is mainly composed of a carbon matrix and a three-dimensional woven carbon fiber preform located therein, and has a multi-layer integrated structure as a whole, with a dense inner layer, a porous middle layer and an outer layer, and the pores are mainly nano-scale pores, and the number of pores in the outer layer is greater than that in the middle layer;

[0409] The volume proportion of the inner layer of the carbon / carbon composite material is 70%, the volume proportion of the middle layer is 15%, and the volume proportion of the outer layer is 15%. The volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material.

[0410] The overall porosity of the carbon / carbon composite material is 6%, the pore volume of the outer layer accounts for 60% of the overall pore volume of the carbon / carbon composite material, the nanoscale pore volume accounts for 60% of all pore volumes, and the average pore size of the nanoscale pores is 50nm;

[0411] The density of carbon / carbon composite material is 1.0g / cm 3 , tensile strength is 620MPa, tensile modulus is 270GPa, flexural strength is 470MPa, and hardness is 15GPa.

[0412] An application of a carbon / carbon composite material, using the carbon / carbon composite material prepared above to prepare a structural battery, specifically: using the carbon / carbon composite material prepared above as the negative electrode of the structural battery, using the carbon / carbon composite material after lithium / sodium ion attachment treatment as the positive electrode of the structural battery, and using a glass fiber separation membrane as a structural battery separator.

Claims

1. A method for preparing a carbon / carbon composite material, characterized in that: A three-dimensional braided carbon fiber preform is impregnated with a liquid high-carbon material and then solidified to obtain a semi-finished product, and the semi-finished product is sequentially subjected to a first-stage carbon treatment, a second-stage carbon treatment, a plasma treatment, and a third-stage carbon treatment to obtain a carbon / carbon composite material; The residual carbon rate of high carbon content materials is 35%-50%; The impregnation adopts vacuum injection infiltration technology; The temperature of the first stage carbon treatment is 900-1100°C, and the time is 5-10h; the temperature of the second stage carbon treatment is 100-400°C higher than that of the first stage carbon treatment, and the time of the second stage carbon treatment is 1-3h shorter than that of the first stage carbon treatment; the temperature of the third stage carbon treatment is 200-500°C higher than that of the second stage carbon treatment, and the time of the third stage carbon treatment is 2-7h shorter than that of the second stage carbon treatment; The plasma treatment uses a plasma emitter with a power of 500-900W and a distance of 3-6cm from the surface of the semi-finished product. The plasma treatment time is 10-60min. The carbon / carbon composite material has a multi-layer integrated structure as a whole, with a dense inner layer, a porous middle layer and an outer layer, and the pores are mainly nanoscale pores; the overall porosity of the carbon / carbon composite material is 2.5-7%, the pore volume of the outer layer accounts for 65-75% of the overall pore volume of the carbon / carbon composite material, the nanoscale pore volume accounts for 60-70% of all pore volumes, and the average pore size of the nanoscale pores is 5-70nm.

2. The method for preparing a carbon / carbon composite material according to claim 1, characterized in that: The viscosity of the high carbon content material at 25°C is 20-2000cps; the injection pressure during impregnation is 0.1-1bar, and the volume ratio of the high carbon content material to the three-dimensional woven carbon fiber preform is 35-46:47-62.5; the curing temperature is 80-190°C, the pressure is 0.1-2MPa, and the time is 0.2-3h.

3. The method for preparing a carbon / carbon composite material according to claim 1, characterized in that: The device used for preparing a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial and a braiding yarn carrier, the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, the number of the angle wheel, the dial and the braiding yarn carrier base are all multiple, characterized in that the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate; The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained; The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts; Area a, area b, and the bottom surface of the base of the braiding yarn carrier are the same in shape and size; All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6´(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer; Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time; n>2; for the cutouts in each 6-cut circular plate of the nth layer that are not opposite to other cutouts, the braiding yarn carrier base in each cutout is filled with one cutout of a 2-cut circular plate, and the other cutout of the 2-cut circular plate is filled with another braiding yarn carrier base; Or, n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the base of the knitting yarn carrier in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base, and the 2-cut circular plate is recorded as dial a; the base of the knitting yarn carrier in cut b is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another knitting yarn carrier base, and the 2-cut circular plate is recorded as dial a; One cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-cut circular plate is recorded as dial b; the braiding yarn carrier base in the cut c fills one cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c; The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are simultaneously controlled to rotate 180° in the same direction. The angle wheels and dials are controlled to rotate in opposite directions. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

4. The method for preparing a carbon / carbon composite material according to claim 1, characterized in that: The device used for preparing a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial and a braiding yarn carrier, the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, the number of the angle wheel, the dial and the braiding yarn carrier base are all multiple, characterized in that the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate; The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained; The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts; The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same; All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6´(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer; Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time; n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the braiding yarn carrier base in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial a; the braiding yarn carrier base in cut b is filled with one One cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, the braiding yarn carrier corresponding to the other braiding yarn carrier base is recorded as braiding yarn carrier b, and the two-cut circular plate is recorded as dial b; the braiding yarn carrier base in the cut c fills one cut of a two-cut circular plate, the other cut of the two-cut circular plate is filled by another braiding yarn carrier base, and the two-cut circular plate is recorded as dial c; The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling all yarn carriers except the woven yarn carrier b to carry yarns, all the yarns are bundled and then rolled up. During the rolling up process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, all the dials except the dial b are rotated 180° at the same time, the rotation directions of the dial a and the dial c are controlled to be opposite, and the rotation directions of the other dials and angle wheels except the dials a~c are controlled to be opposite. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

5. The method for preparing a carbon / carbon composite material according to claim 1, characterized in that: The device used for preparing a three-dimensional braided carbon fiber preform comprises a chassis, an angle wheel, a dial and a braiding yarn carrier, the braiding yarn carrier comprises a braiding yarn carrier base and a braiding yarn carrier straight rod, the number of the angle wheel, the dial and the braiding yarn carrier base are all multiple, characterized in that the angle wheel is a 6-cut circular plate, and the dial is a 2-cut circular plate; The formation process of the 6-cut circular plate is as follows: select 6 regions a with the same shape and size, which do not overlap each other and are evenly distributed around the central circumference of the circular plate u on the circular plate u, and the regions a are surrounded by 2 arcs, one of which coincides with the edge of the circular plate u. After the 6 regions a are cut to form 6 cuts, the 6-cut circular plate is obtained; The formation process of the 2-cut circular plate is as follows: select two regions b on the circular plate v that are of the same shape and size, do not overlap each other and are evenly distributed around the central circumference of the circular plate u, the regions b are surrounded by two arcs and one of the arcs coincides with the edge of the circular plate v, and the 6-cut circular plate is obtained after the two regions b are cut to form two cuts; The shape and size of the area a, area b and the bottom surface of the base of the braiding yarn carrier are the same; All the 6-cut circular plates are distributed in n layers, n≥2, and each layer is numbered from 1 from the inside to the outside. The number of 6-cut circular plates in the first layer is 1, and the number of 6-cut circular plates in the i-th layer is 6´(i-1), 2≤i≤n, and any two adjacent 6-cut circular plates are arranged at a distance; the 6-cut circular plates in the i-th layer are evenly distributed and the center point connection line forms a regular hexagon, and the vertices of the regular hexagons corresponding to the 2nd to nth layers are distributed on the 6 lines radiating outward from the center point of the 6-cut circular plate in the first layer; Each cut of the 6-cut circular plate is filled with a braided yarn carrier base; any two adjacent 6-cut circular plates have one cut facing each other, and the braided yarn carrier bases in the two opposite cuts are filled with two cuts of a 2-cut circular plate at the same time; n=2; in each 6-cut circular plate of the nth layer, the number of cuts that are not opposite to other cuts is 3, which are respectively recorded as cut a, cut b and cut c, and cut b is located between cut a and cut c; the braiding yarn carrier base in cut a is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial a; the braiding yarn carrier base in cut b is not filled with one cut of a 2-cut circular plate; the braiding yarn carrier base in cut c is filled with one cut of a 2-cut circular plate, and the other cut of the 2-cut circular plate is filled with another braiding yarn carrier base, and the 2-cut circular plate is recorded as dial c; The specific process of preparing a three-dimensional woven carbon fiber preform is as follows: after controlling each yarn carrier to carry yarn, all the yarns are bundled and then reeled up. During the reeling process, all the angle wheels are alternately controlled to rotate 60° in the same direction at the same time, and all the dials are rotated 180° at the same time. The rotation directions of dial a and dial c are controlled to be opposite, and the rotation directions of other dials and angle wheels except dial a and dial c are controlled to be opposite. After multiple cycles, a three-dimensional woven carbon fiber preform is obtained.

6. A device for implementing the method for preparing a carbon / carbon composite material as claimed in any one of claims 1 to 5, characterized in that: Including semi-finished product continuous processing equipment, carbonization equipment, plasma treatment equipment; The semi-finished product continuous processing equipment includes a high-carbon material injection machine and a preparation device for three-dimensional woven carbon fiber preforms arranged in sequence along the conveying direction, a preforming device, an infiltration and curing integrated molding mold, a post-processing device, a drawing device, and a cutting device.

7. A carbon / carbon composite material prepared by the method for preparing a carbon / carbon composite material as claimed in any one of claims 1 to 5.

8. A carbon / carbon composite material according to claim 7, characterized in that: The volume proportion of the inner layer of the carbon / carbon composite material is 70-75%, the volume proportion of the middle layer is 10-15%, and the volume proportion of the outer layer is 10-15%. The volume proportion of each layer is the percentage of the sum of the solid volume and the pore volume of the layer to the sum of the solid volume and the pore volume of the carbon / carbon composite material. The density of carbon / carbon composite materials is 0.7-1.8g / cm 3 , tensile strength is 600-800MPa, tensile modulus is 250-400GPa, flexural strength is 450-700MPa, and hardness is 10-60GPa.

9. Use of a carbon / carbon composite material as claimed in claim 7 or 8, characterized in that: Used as electrodes in structural batteries.

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