CVD (Chemical Vapor Deposition) coating furnace for silicon-carbon negative electrode material

Abstract

According to the silicon-carbon negative electrode material CVD deposition coating furnace provided by the invention, a plurality of silicon carbide sintered plates are spliced to form a large furnace liner, so that the industrial problem of manufacturing a large-size and high-barrel silicon carbide furnace liner through integral sintering is solved, and high cleanliness of a reaction environment is ensured; due to the design of the spliced silicon carbide microporous fluidization plate, the material leakage is effectively prevented while the high pore distribution rate is ensured to realize low-air-pressure efficient fluidization, and the difficulty in integral forming of a large-size fluidization plate is overcome. The resistance heating mode arranged in the center of the furnace body is combined with the external silicon carbide heat transfer pipe, a uniform and stable radial radiation thermal field is created, the deposition coating efficiency and uniformity are remarkably improved, and the silicon carbide heat transfer pipe serves as a key barrier and thoroughly isolates a metal heating element from reaction materials. The whole equipment realizes high-purity, high-efficiency and large-scale continuous CVD deposition coating production of the silicon-carbon negative electrode material under the conditions of high temperature, isolation of metal and air.

Description

Technical Field

[0001] This invention relates to the field of battery anode material technology, and in particular to a CVD deposition coating furnace for silicon-carbon anode materials. Background Technology

[0002] Silicon-carbon composite materials, as anode materials for lithium-ion batteries, are considered a key direction for improving battery energy density due to their theoretical specific capacity being far higher than that of traditional graphite materials. Chemical vapor deposition (CVD) is an effective method for preparing high-performance silicon-carbon anode materials, especially for uniformly coating nano-silicon layers on porous carbon substrates. This method decomposes precursor gases such as silanes at high temperatures, and the resulting silicon atoms are deposited and embedded in the pores of the carbon material, thereby forming a structurally stable composite. An ideal CVD process can significantly improve the electrochemical performance of the material and is expected to enable fast charging.

[0003] However, applying CVD technology to the industrial continuous production of silicon-carbon anode materials faces a series of severe technical challenges. First, the reaction process needs to be carried out at a high temperature of 600-800℃, and the material (porous carbon) must be in a fluidized state to ensure sufficient contact and uniform coating between the gas and solid. Existing fluidized bed production equipment is typically small-scale, mostly at the level of hundreds of kilograms per day, which is insufficient to meet the needs of large-scale production. One of the key factors limiting its scale-up lies in the construction of the core reactor—the fluidized bed deposition furnace. Traditional metal furnace shells are prone to reacting with active silicon components at high temperatures, introducing impurities. Using inert ceramic materials (such as silicon carbide) to manufacture large, especially large-diameter, tall, integral furnace shells presents problems such as difficult sintering, low yield, and high cost.

[0004] Secondly, the production process has extremely stringent requirements for isolating specific impurities. On the one hand, silicon materials cannot come into contact with any metal components at high temperatures; otherwise, they will react with metal ions to generate impurity phases with poor conductivity or electrochemical inertness, severely damaging the capacity and cycle life of the final battery product. On the other hand, the entire material handling process must be carried out under an inert atmosphere (such as nitrogen) to strictly isolate oxygen and prevent the silicon or intermediate products from being oxidized. This requires the equipment to have extremely high sealing performance, especially at the inlet and outlet ports, temperature and pressure measuring element interfaces, and furnace body joints.

[0005] Furthermore, the process requires precise intelligent control. CVD deposition is a complex process involving gas-solid heat and mass transfer and surface reactions. The uniformity, thickness, and density of the coating directly affect material properties. Real-time monitoring and stable control of key parameters such as reaction temperature, gas flow rate and ratio, and fluidization state are necessary. Existing equipment still has shortcomings in achieving uniform temperature field, uniform gas distribution, and continuous and stable process control within large-scale fluidized beds.

[0006] Therefore, there is an urgent need in this field to develop a CVD deposition coating equipment suitable for the industrial production of silicon-carbon anode materials. This equipment needs to be able to achieve large-scale continuous operation, its core reaction chamber must be able to withstand high temperatures, be completely inert to avoid contamination, and have excellent sealing performance to maintain a high-purity reaction environment. At the same time, it is also necessary to solve the manufacturing problem of large-scale high-temperature resistant inert furnaces and integrate advanced temperature control and process control systems. Summary of the Invention

[0007] The purpose of this invention is to provide a CVD deposition and coating furnace for silicon-carbon anode materials to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] This invention provides a CVD deposition coating furnace for silicon-carbon anode materials, comprising:

[0010] The furnace body has an outer shell, and its inner wall is equipped with a heat insulation layer;

[0011] A silicon carbide lining is installed inside the furnace shell. The silicon carbide lining is made of multiple silicon carbide sintered plates spliced ​​together by seams and bonded with special adhesive to form a cylindrical furnace liner.

[0012] A silicon carbide microporous fluidizing plate is disposed at the bottom of the silicon carbide liner. The silicon carbide microporous fluidizing plate is composed of multiple fan-shaped plates spliced ​​together, and has micropores with a diameter of 0.3 μm and a porosity of more than 45%.

[0013] The lower gas chamber is connected to the bottom of the furnace shell and is located below the silicon carbide microporous fluidizing plate. The lower gas chamber is provided with an inlet pipe for introducing reaction gas.

[0014] The lower gas chamber is connected to the bottom of the furnace shell and is located below the silicon carbide microporous fluidizing plate. The lower gas chamber is provided with an inlet pipe for introducing reaction gas.

[0015] A silicon carbide heat transfer tube is fitted outside the heating device to transfer heat to the reaction area and isolate the heating device from the material.

[0016] A furnace top heat dissipation device is installed on the top of the furnace shell to cool the furnace top area;

[0017] The feed pipe, return pipe, and exhaust pipe are located on the upper part of the furnace shell.

[0018] A silicon carbide discharge pipe is located below the silicon carbide microporous fluidizing plate for unloading.

[0019] The material circulation system connects the exhaust pipe, filter, blower and return pipe in sequence through pipelines.

[0020] Preferably, the space between the silicon carbide lining and the insulation layer of the inner wall of the furnace body is filled with a refractory and heat-insulating castable composed of refractory mortar and refractory filler, and the insulation layer contains aluminum silicate fiber; the furnace body shell is provided with furnace body support lugs for installation and fixation in the middle.

[0021] Preferably, the silicon carbide microporous fluidizing plate is funnel-shaped with a cone angle of 120-180 degrees; the silicon carbide microporous fluidizing plate is supported by a bracket steel ring and a fluidizing plate bracket provided below it, and the flange of the silicon carbide discharge pipe is embedded in the countersunk step of the bracket steel ring.

[0022] Preferably, the air inlet pipes provided on the lower air chamber include a first air inlet pipe, a second air inlet pipe, and a third air inlet pipe, which are used to introduce nitrogen, silane, and acetylene gas, respectively; the lower air chamber is also provided with a thermocouple mounting pipe.

[0023] Preferably, the heating device includes:

[0024] Stainless steel heating tubes are vertically installed in the center of the furnace body;

[0025] The heating element is located inside the stainless steel heating tube;

[0026] An electrode flange is located at the top of the stainless steel heating tube;

[0027] And an electrode assembly, which is electrically connected to the heating element.

[0028] Preferably, a 310s stainless steel electrode skeleton tube is provided at the center of the electrode flange, a thermocouple is installed inside the stainless steel electrode skeleton tube, and the stainless steel electrode skeleton tube is used to introduce nitrogen gas into the stainless steel heating tube; an electrode partition is provided between the electrode flange and the stainless steel heating tube.

[0029] Preferably, the furnace top heat dissipation device includes an upper water tank and a lower water tank arranged vertically. The upper water tank is provided with an upper water tank inlet pipe and an upper water tank outlet pipe, and the lower water tank is provided with a lower water tank inlet pipe and a lower water tank outlet pipe. The upper end of the silicon carbide heat transfer tube is installed in a floating manner within a support flange, and the support flange is connected between the upper flange of the lower water tank and the lower flange assembly of the upper water tank. The upper water tank is provided with an upper flange at the top.

[0030] Preferably, a silicon carbide furnace cover is installed on the top of the furnace shell via a connecting flange assembly. The silicon carbide furnace cover is made of multiple silicon carbide plates spliced ​​together with internal and external seams and connected with putty. A silicon carbide spacer is also provided above the silicon carbide furnace cover.

[0031] Preferably, the bottom of the filter is provided with a filter ash outlet, which is connected to the return pipe through an ash outlet pipe and a bracket sealing valve; the outlet of the blower is connected to an air inflator through a blower pipe, and the air inflator is connected to the feeding system; the outlet of the filter is connected to the inlet of the blower through an air outlet pipe, and an air supply pipe is also connected to the air outlet pipe.

[0032] Preferably, the heating device is a three-phase 380V resistance heater; the upper part of the furnace body is provided with a thermocouple tube for monitoring the furnace temperature, and the power supply is automatically adjusted by the control system connected to the thermocouple to maintain the furnace temperature at 600℃; at the pipe connection between the outer shell of the furnace body and the upper part of the silicon carbide lining, ceramic fiber bundles are filled in the gap between the silicon carbide sintering cylinder and the stainless steel outer sleeve; the flange of the silicon carbide heat transfer tube is fixed by compression wire assisted fixation.

[0033] The present invention achieves the following beneficial technical effects compared to the prior art:

[0034] This invention provides a CVD deposition and coating furnace for silicon-carbide anode materials. By employing multiple silicon carbide sintered plates spliced ​​together to form a large furnace liner, it innovatively solves the industry challenge of manufacturing large-size, tall silicon carbide furnace liners through integral sintering. This significantly increases equipment capacity and ensures a highly clean reaction environment, avoiding metal contamination. The unique spliced ​​silicon carbide microporous fluidizing plate design ensures a high porosity for efficient fluidization under low air pressure while effectively preventing material leakage and overcoming the difficulties of integral forming of large-size fluidizing plates. The resistance heating method located at the center of the furnace body, combined with external silicon carbide heat transfer tubes, creates a uniform and stable radial radiation heat field, significantly improving the efficiency and uniformity of deposition and coating. Simultaneously, the silicon carbide heat transfer tubes act as a critical barrier, completely isolating the metal heating elements from the reactants, constituting an intrinsically safe design. The high-efficiency cooling water tank system on the furnace top protects the top flange assembly and extends the equipment's lifespan. The entire equipment, through its all-silicon carbide contact surface, rigorous sealing design, and integrated material circulation and atmosphere control system, has successfully achieved high-purity, high-efficiency, and large-scale continuous CVD deposition and coating production of silicon-carbon anode materials under high-temperature, metal- and air-isolated conditions. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the CVD deposition coating furnace structure for silicon-carbon anode materials provided by this invention;

[0037] In the diagram: 1. Furnace shell, 2. Silicon carbide lining, 3. Silicon carbide heat transfer tube, 4. Heating element, 5. Electrode flange, 6. Electrode assembly, 7. Upper flange of upper water tank, 8. Upper flange of lower water tank, 9. Support flange, 10. Lower flange assembly of upper water tank, 11. Upper water tank, 12. Upper water tank outlet pipe, 13. Upper water tank inlet pipe, 14. Lower water tank inlet pipe, 15. Lower water tank, 16. Lower water tank outlet pipe, 17. Silicon carbide furnace cover, 18. Exhaust pipe, 19. Feed pipe, 20. Return pipe, 21. Ceramic fiber bundle, 22. Silicon carbide microporous fluidizing plate, 23. Silicon carbide discharge pipe, 24. 25. Lower air chamber, 26. First air inlet pipe, 27. Second air inlet pipe, 28. Bracket steel ring, 29. Fluidized plate bracket, 30. Third air inlet pipe, 31. Thermocouple, 32. Pressing wire, 33. Partition plate, 34. Insulation layer, 35. Connecting flange assembly, 36. Furnace body support lug, 37. Refractory heat-insulating castable, 38. Silicon carbide spacer, 39. Bracket sealing valve, 40. Stainless steel heating tube, 41. Thermocouple tube, 42. Ash outlet of purifier, 43. Filter, 44. Ash outlet pipe, 45. Blower, 46. Blower pipe, 47. Air conditioner, 48. Gas transmission pipe. Detailed Implementation

[0038] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] The purpose of this invention is to provide a CVD deposition coating furnace for silicon-carbon anode materials to solve the problems existing in the prior art.

[0042] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1:

[0044] Please see Figure 1 This invention provides a silicon-carbon anode material CVD deposition coating furnace, which aims to solve the problems of small scale, susceptibility to metal contamination, poor sealing and uneven temperature field in the existing silicon-carbon anode material CVD coating production equipment, and realize large-scale, high-purity and high-efficiency continuous production.

[0045] The main structure of the deposition coating furnace includes a furnace shell 1, an inner silicon carbide lining 2, a bottom silicon carbide microporous fluidizing plate 22, a central heating device, and a furnace top heat dissipation device.

[0046] The furnace shell 1, serving as the external support and protection structure of the equipment, is made of steel plate with a thickness of 12-20mm rolled into a cylinder with a diameter of 1-5 meters. To reduce heat loss, an insulation layer 33 composed of materials such as aluminum silicate fiber is laid on the inner wall of the furnace shell 1. Furnace support lugs 35 are welded to the outer side of the middle part of the furnace shell 1 to facilitate the stable installation of the entire furnace body on the external steel frame.

[0047] To achieve absolute inertia and cleanliness of the reaction chamber at high temperatures, a silicon carbide liner 2, composed of sintered silicon carbide material, is installed inside the insulation layer 33, forming the furnace liner. This silicon carbide liner 2 employs an innovative splicing structure, consisting of multiple sintered silicon carbide plates joined together through precisely designed interlocking seams, with the seams coated with a special high-temperature adhesive for bonding. During subsequent furnace firing, the adhesive generates silicon carbide joints, ensuring the strength and sealing of the joints and effectively preventing gas leakage. This splicing design allows for the manufacture of large furnace liners with inner diameters ranging from 1-5 meters and heights from 4-20 meters, breaking through the technical bottleneck of integrally sintered large-size silicon carbide components. The silicon carbide liner 2 is only 10-30 mm thick, yet its compressive strength at high temperatures remains above 100 MPa. To further enhance the structural integrity and thermal insulation performance, a refractory insulating castable 36 composed of refractory mortar and refractory filler is filled in the gap between the silicon carbide inner lining 2 and the outer insulation layer 33. After solidification and baking, a solid composite insulation layer is formed.

[0048] Several functional pipes are installed in the upper area of ​​the furnace shell 1 and the silicon carbide lining 2. Specifically, an exhaust pipe 18 is installed to discharge reaction tail gas; a thermocouple tube 40 is installed on the opposite side to install a thermocouple for monitoring the temperature of the upper part of the furnace; and a feed pipe 19 and a return pipe 20 are installed in the middle. The feed pipe 19 is used to add porous carbon powder and other raw materials into the furnace. All pipes penetrating the furnace wall adopt a composite structure: a silicon carbide sintered round tube is inserted in the middle as an inert lining in contact with the material, and a 304 stainless steel round tube is fitted on the outside and welded to the furnace shell 1. A flange is welded to the upper end. Ceramic fiber bundles 21 and baffles 32 are installed on the upper part of the heating element 4 and pressed with clamping wire 31 to achieve sealing and heat insulation.

[0049] One of the core components of the furnace reaction zone is the silicon carbide microporous fluidizing plate 22 located at the bottom of the silicon carbide lining 2. This fluidizing plate 22 is funnel-shaped with a cone angle of 120-180 degrees. It also employs a segmented splicing technique to address the challenge of large-size integral sintering, consisting of 6-18 fan-shaped silicon carbide plates connected by seams and sealed with adhesive. The fluidizing plate 22 is densely covered with micropores, each with a diameter of 0.3 μm and a porosity exceeding 45%. This design ensures uniform gas flow while effectively preventing powder leakage. The silicon carbide microporous fluidizing plate 22 is supported and fixed by a bracket steel ring 27 welded to the furnace body below and multiple fluidizing plate brackets 28. A silicon carbide discharge pipe 23 is connected to the lower center of the fluidizing plate 22 for discharging the material after the reaction is complete. The flange of the silicon carbide discharge pipe 23 is placed in the countersunk step machined from the inner hole of the bracket steel ring 27, and is covered with a 316 stainless steel sleeve to enhance mechanical strength. The middle part of the sleeve is welded to the lower air chamber 24 at the bottom.

[0050] The lower gas chamber 24 is a hemispherical cavity connected to the bottom of the furnace shell 1 via a large flange. Multiple inlet pipes are provided on the lower gas chamber 24, including a first inlet pipe 25 for introducing nitrogen, a second inlet pipe 26 for introducing silane gas, and a third inlet pipe 29 for introducing acetylene gas. In addition, a thermocouple mounting tube 30 is installed inside the lower gas chamber 24 for monitoring the inlet gas temperature. During the reaction, a mixed gas at a certain pressure flows upward from the lower gas chamber 24 through the micropores of the silicon carbide microporous fluidized bed 22, entering the furnace and blowing up the porous carbon powder located on the fluidized bed to form a fluidized bed of stable height.

[0051] The heat required for the reaction is provided by a heating device located on the central axis of the furnace. This heating device uses internal heating and mainly includes a stainless steel heating tube 39, a heating element 4 placed inside it, an electrode flange 5 at the top, and an electrode assembly 6 connected to an external power source. The heating element 4 is a three-phase 380V resistance heater. During installation, the entire heating element 4 is inserted into the center of the stainless steel heating tube 39, and the electrode flange 5 is connected to the flange at the top of the stainless steel heating tube 39 by screws. An electrode partition 32 is provided between the two for insulation. A 310s stainless steel electrode frame tube runs through the center of the electrode flange 5. This tube has multiple functions: first, it serves as the mounting frame for the resistance wire assembly of the heating element 4; second, a thermocouple 40 is installed in its inner hole for accurate monitoring of the temperature near the heating element; third, nitrogen gas can be continuously introduced into the stainless steel heating tube 39 through the inner hole of this tube to replace the internal air, prevent the resistance wire from oxidizing at high temperatures, and thus extend its service life.

[0052] To completely isolate the metal heating element from the reactants, a silicon carbide heat transfer tube 3 is tightly fitted around the stainless steel heating tube 39. The silicon carbide heat transfer tube 3 can withstand temperatures exceeding 1400℃ and has excellent thermal radiation performance, allowing it to evenly radiate heat from the center to the surrounding fluidized bed. It forms a permanent physical barrier between the material and the stainless steel heating tube 39. Even if the heat transfer tube cracks due to extreme conditions, the internal metal heating element remains protected by the stainless steel tube, preventing material contact and greatly enhancing equipment safety.

[0053] The top of the furnace body is a region with concentrated heat and a complex structure. A silicon carbide furnace cover 17 is installed on the top of the furnace shell 1 via a connecting flange assembly 34. This cover is also constructed from 8-18 silicon carbide plates joined together with internal and external seams and sealed with putty to ensure a tight seal. A silicon carbide spacer 37 is also installed above the silicon carbide furnace cover 17. A dedicated furnace top heat dissipation device is installed to protect the top flange assembly from high-temperature damage. This device includes an upper water tank 11 and a lower water tank 15 arranged vertically. The lower water tank 15 is hemispherical, with an upper flange 8 welded to its upper part, connected to the lower flange assembly 10 of the upper water tank via a support flange 9. The upper flange of the silicon carbide heat transfer tube 3 is installed in a floating manner: a 10mm thick ceramic fiber rope pad is placed under the flange edge, and then it is placed on the inner edge of the support flange 9, with a gap of approximately 5mm at the top. This floating installation method avoids damage to the silicon carbide components due to thermal expansion and contraction or installation stress. The upper water tank 11 is equipped with an upper water tank inlet pipe 13 and an upper water tank outlet pipe 12, and the lower water tank 15 is equipped with a lower water tank inlet pipe 14 and a lower water tank outlet pipe 16. The residual heat accumulated at the top is removed through continuous water circulation. The upper water tank 11 is equipped with an upper water tank flange 7 at the top. This flange is connected in series with the flange of the stainless steel heating tube 39 and the electrode flange 5 through an extended screw to form a stable flange assembly.

[0054] To achieve material recycling and closed-loop system operation, this invention establishes a complete material recycling system. During the reaction process, waste gas carrying fine powder is discharged from the exhaust pipe 18 at the top of the furnace and enters the filter 42. After filtration, the clean hot air is drawn and pressurized by the blower 45 through the exhaust pipe 44, and then transported to the air conditioner 47 connected to the feeding system through the blower pipe 46. This portion of hot air can be reused for material conveying or fluidization, achieving heat recovery. The useful fine powder retained by the filter 42 is sent back to the return pipe 20 through the filter ash outlet 41 and ash pipe 43 at its bottom, via the nut-shaped sealing valve 38 (a valve with sealing function), and finally returned to the reaction zone inside the furnace for re-coating, thereby improving the raw material utilization rate. A gas delivery pipe 48 is also connected to the exhaust pipe 44, which can export excess process gas to the tail gas treatment system (such as a liquid seal tank or flare) for safe disposal.

[0055] The working principle of this invention is as follows: First, porous carbon powder raw material is added into the furnace through the feed pipe 19 and piled on the silicon carbide microporous fluidized plate 22. Then, nitrogen is introduced into the system to replace the air. The central heating device is started, and the temperature of the fluidized bed area in the furnace is controlled at about 600°C through thermocouple 40 and the control system. At the same time, a mixture of nitrogen, silane and acetylene gas in a certain proportion is introduced from the lower gas chamber 24. The gas flows upward uniformly through the micropores of the fluidized plate, so that the porous carbon powder forms a stable fluidized state. At high temperature, silane gas decomposes to generate monomeric silicon and hydrogen. The monomeric silicon fully collides and contacts with the porous carbon particles in the fluidized state, and gradually embeds itself into the pores of the carbon material through the CVD vapor deposition mechanism to form a silicon-carbon composite anode material. This coating process lasts for about 7-9 hours. The reaction tail gas and the entrained fine powder enter the material circulation system through the exhaust pipe. The fine powder is recovered and sent back to the furnace, and the gas is treated and then discharged or reused. After the reaction is complete, heating and gas intake are stopped, and the final product is discharged through silicon carbide discharge pipe 23.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] It should be noted that the components mentioned in the above embodiments are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0058] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A silicon-carbon anode material CVD deposition coating furnace, characterized in that, The application relates to a carbonization furnace, which comprises the following parts: a furnace body shell (1) with an inner wall provided with a heat preservation layer (33); a silicon carbide inner liner (2) arranged in the furnace body shell (1), wherein the silicon carbide inner liner (2) is formed by splicing and bonding a plurality of silicon carbide sintered plates through a primary-secondary joint and adopting special cement, and the silicon carbide inner liner (2) is in a cylindrical shape; a silicon carbide microporous fluidization plate (22) arranged at the bottom of the silicon carbide inner liner (2), wherein the silicon carbide microporous fluidization plate (22) is formed by splicing a plurality of fan-shaped plates, and micropores are arranged on the silicon carbide microporous fluidization plate (22), the micropores have a diameter of 0.3 micrometers, and the hole distribution rate is higher than 45%; a lower gas chamber (24) connected to the bottom of the furnace body shell (1) and located below the silicon carbide microporous fluidization plate (22), wherein the lower gas chamber (24) is provided with a gas inlet pipe for feeding reaction gas; a heating device vertically arranged at the central axis position of the furnace inner liner and used for providing a heat source for the furnace; a silicon carbide heat transfer pipe (3) sleeved on the outside of the heating device and used for transferring heat to a reaction area and isolating the heating device from materials; a furnace top heat dissipation device arranged at the top of the furnace body shell (1) and used for cooling the top area of the furnace; a feeding pipe (19), a material returning pipe (20) and an exhaust pipe (18) arranged on the upper part of the furnace body shell (1); a silicon carbide discharging pipe (23) arranged below the silicon carbide microporous fluidization plate (22) and used for discharging materials; a material circulation system, wherein the material circulation system is connected with the exhaust pipe (18), a filter (42), a blower (45) and the material returning pipe (20) in sequence through pipelines.

2. The silicon-carbon negative electrode material CVD deposition coating furnace of claim 1, wherein, The silicon carbide inner liner (2) and the heat preservation layer (33) of the inner wall of the furnace body shell (1) are filled with refractory insulating castable (36) composed of refractory cement and refractory filler, the heat preservation layer (33) contains aluminum silicate fibers, and the middle part of the furnace body shell (1) is provided with a furnace body support lug (35) for fixed installation.

3. The silicon-carbon anode material CVD deposition coating furnace of claim 1, wherein, The silicon carbide microporous fluidization plate (22) is in a funnel shape, the taper angle of the silicon carbide microporous fluidization plate (22) is 120-180 degrees, the silicon carbide microporous fluidization plate (22) is supported through a bracket steel ring (27) and a fluidization plate bracket (28) arranged below the silicon carbide microporous fluidization plate (22), and the flange edge of the silicon carbide discharging pipe (23) is embedded in the counterbore step of the bracket steel ring (27).

4. The silicon-carbon anode material CVD deposition coating furnace of claim 1, wherein, The gas inlet pipe arranged on the lower gas chamber (24) comprises a first gas inlet pipe (25), a second gas inlet pipe (26) and a third gas inlet pipe (29) for feeding nitrogen, silane and acetylene gas respectively, and the lower gas chamber (24) is further provided with a thermocouple installation pipe (30).

5. The silicon-carbon anode material CVD deposition coating furnace of claim 1, wherein, The heating device comprises: a stainless steel heating pipe (39) vertically arranged at the center of the furnace body; a heating element (4) arranged in the stainless steel heating pipe (39); an electrode flange (5) arranged at the top of the stainless steel heating pipe (39); and an electrode group (6) electrically connected with the heating element (4).

6. The silicon-carbon anode material CVD deposition coating furnace of claim 5, wherein, The electrode flange (5) is centrally provided with a 310s stainless steel electrode skeleton pipe, a thermocouple (40) is installed in the stainless steel electrode skeleton pipe, and the stainless steel electrode skeleton pipe is used for introducing nitrogen into the inside of the stainless steel heating pipe (39); an electrode partition plate (32) is arranged between the electrode flange (5) and the stainless steel heating pipe (39).

7. The silicon-carbon anode material CVD deposition coating furnace of claim 1, wherein, The furnace top heat dissipation device comprises upper and lower water tanks (11) and (15), the upper water tank (11) is provided with an upper water tank water inlet pipe (13) and an upper water tank water outlet pipe (12), the lower water tank (15) is provided with a lower water tank water inlet pipe (14) and a lower water tank water outlet pipe (16); the upper end of the silicon carbide heat transfer pipe (3) is arranged in a floating mounting manner in a pipe supporting flange (9), the pipe supporting flange (9) is connected between a lower water tank upper flange (8) and a upper water tank lower flange set (10); the upper end of the upper water tank (11) is provided with an upper water tank upper flange (7).

8. The silicon-carbon anode material CVD deposition coating furnace of claim 7, wherein, The furnace body shell (1) is provided with a silicon carbide furnace upper cover (17) on the top through a connecting flange set (34), the silicon carbide furnace upper cover (17) is formed by splicing a plurality of silicon carbide plates through male and female joints and connecting the silicon carbide plates by means of mortar; the silicon carbide furnace upper cover (17) is further provided with a silicon carbide spacer sleeve (37) above.

9. The silicon-carbon anode material CVD deposition coating furnace of claim 1, wherein, The filter (42) is provided with a filter ash outlet (41) at the bottom, the filter ash outlet (41) is connected with the return pipe (20) through an ash outlet pipe (43) and a bracket seal valve (38); the outlet of the air blower (45) is connected with an aerator (47) through an air blowing pipe (46), the aerator (47) is communicated with the material feeding system; the outlet of the filter (42) is connected with the inlet of the air blower (45) through an air outlet pipe (44), and a gas conveying pipe (48) is further connected to the air outlet pipe (44).

10. The silicon-carbon anode material CVD deposition coating furnace of claim 1, wherein, The heating device is a three-phase 380V resistance heater; the furnace body is provided with a thermocouple pipe (40) at the upper part for monitoring the furnace temperature, and the control system connected with the thermocouple is used for automatically regulating and controlling the power to maintain the furnace temperature at 600℃; the gap between the silicon carbide sintering cylinder and the stainless steel outer sleeve pipe at the pipe connection position of the furnace body shell (1) and the silicon carbide lining (2) is filled with a ceramic fiber block (21); the flange of the silicon carbide heat transfer pipe (3) is fixed by means of compression wire drawing (31). The electrode flange (5) is centrally provided with a 310s stainless steel electrode skeleton pipe, a thermocouple (40) is installed in the stainless steel electrode skeleton pipe, and the stainless steel electrode skeleton pipe is used for introducing nitrogen into the inside of the stainless steel heating pipe (39); an electrode partition plate (32) is arranged between the electrode flange (5) and the stainless steel heating pipe (39).

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