Silicon negative electrode CVD and carbon coating equipment and continuous mass production method

Abstract

The present invention relates to silicon anode CVD and carbon coating equipment and a continuous mass production method, and relates to the field of silicon anode production. One end of the reactor is rotatably connected and communicated with a carbon rack feeding device, and the other end thereof extends into a fluidizing chamber and is rotatably connected to the upper portion of the fluidizing chamber. The sidewall of the other end of the reactor has multiple fluidizing holes. One end of the reactor is also provided with an exhaust hole, which is connected to the upper portion of the fluidizing chamber via an exhaust fan. The upper portion of the fluidizing chamber has an upper air inlet, which allows monosilane and nitrogen to be introduced into the upper air inlet. The lower portion of the fluidizing chamber has a lower air inlet, which allows acetylene and nitrogen to be introduced into the lower air inlet. The bottom of the fluidizing chamber has a discharge hole, and a heater is fixedly connected to the inner wall of the fluidizing chamber. The reactor and the fluidizing chamber are in a high-temperature, low-oxygen environment, and silicon anode products can be produced continuously in the reactor and the fluidizing chamber without stopping, thereby increasing the yield of silicon anodes, reducing production costs, and enabling large-scale production and use of silicon anodes.

Description

Technical Field

[0001] The present invention relates to the field of silicon negative electrode production, and in particular to silicon negative electrode CVD and carbon coating equipment and a continuous mass production method. Background Art

[0002] Traditional graphite anodes have a gram capacity of only approximately 370 mAh / g, and their layered structure limits their ability to absorb lithium ions, resulting in slow charging. Graphite anodes also pose a safety risk of fire. In comparison, silicon-carbon anodes offer significant advantages: silicon's gram capacity can reach up to 4200 mAh / g, and the porous structure of the carbon-based material enables faster charging than graphite. However, silicon expands more than three times its volume after charging, posing an explosion risk when used alone. The porous structure of the carbon matrix can alleviate this problem to some extent. Silicon-carbon anodes are based on a porous carbon framework (also known as a carbon-based framework, carbon skeleton, etc.), which provides porous, expandable space, thereby ensuring the structural stability and performance of the anode material. The carbon framework can be made of materials such as resin and coconut shell.

[0003] Currently, the industrial application of silicon-carbon anodes faces several challenges. The low production volume and high cost of silicon-based materials have hindered their large-scale application.

[0004] In terms of production technology, CVD (chemical vapor deposition) is one of the main methods for preparing silicon-carbon anode materials. This process uses monosilane (SiH4) as the raw material, decomposing it through heating to produce elemental silicon, which is then deposited on a carbon frame to form a deposited product. The deposited product is then coated with a layer of elemental carbon (carbon coating) to protect the deposited product inside.

[0005] CVD production equipment typically consists of two options: rotary kilns and fluidized beds. 1. Rotary kilns are suitable for larger production volumes, but can only produce 1kg per run and require 8 hours. Silane is flammable and explosive in the presence of oxygen, posing production risks. Therefore, rotary kilns must be operated under sealed, pressurized conditions, preventing continuous production. Furthermore, rotary kilns present issues such as dead spots and uneven reactions, making it difficult to increase production by scaling up the equipment. 2. Fluidized bed equipment offers significant advantages in terms of product quality uniformity, but it also faces bottlenecks such as inability to achieve continuous and mass production. The fluidized bed CVD process requires premixing of raw materials, followed by a heating and cooling cycle to complete a single CVD run (commonly known as a "one-pot"), which takes 6-8 hours. The output per unit is currently less than 10kg per pot.

[0006] Moreover, in the prior art, the CVD and carbon coating processes are implemented using two independent sets of equipment. Since the CVD production equipment cannot achieve continuous production, each time the CVD production equipment produces a deposited product, it is necessary to open the sealed CVD production equipment, take out the deposited product, and then put it into the carbon coating production equipment. This greatly increases the production time and cost, making the production cost of the silicon-carbon negative electrode (hereinafter referred to as silicon negative electrode) high and difficult to apply on a large scale. Summary of the Invention

[0007] The technical problem to be solved by the present invention is how to continuously produce silicon negative electrodes.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a silicon negative electrode CVD and carbon coating equipment, including a carbon rack feeding device, a reactor, a fluidizing chamber, a heater and an exhaust fan, one end of the reactor is rotatably connected and communicated with the carbon rack feeding device, and the other end thereof extends into the fluidizing chamber and is rotatably connected to the upper part of the fluidizing chamber, the side wall of the other end of the reactor has a plurality of fluidizing holes, and one end of the reactor is also provided with an exhaust hole, and the exhaust hole is communicated with the upper part of the fluidizing chamber through the exhaust fan, the upper part of the fluidizing chamber has an upper air inlet, and the upper air inlet is used to introduce monosilane and nitrogen, the lower part of the fluidizing chamber has a lower air inlet, and the lower air inlet is used to introduce acetylene and nitrogen, the bottom of the fluidizing chamber has a discharge hole, and the heater is fixedly connected to the inner wall of the fluidizing chamber.

[0009] The present invention has the following beneficial effects: a porous carbon rack is fed into a reactor via a carbon rack feeding device; a heater is used to create a high-temperature environment within the fluidization chamber, and monosilane and nitrogen are introduced through the upper air inlet, where the monosilane is thermally cracked into elemental silicon and hydrogen. An exhaust fan provides power, allowing gas and elemental silicon in the upper portion of the fluidization chamber to enter the reactor through the fluidization holes and then return to the fluidization chamber through the air extraction holes. Within the reactor, the elemental silicon and the carbon rack come into countercurrent contact, achieving full contact and depositing within the carbon rack pores, thereby producing a deposition product, thereby achieving chemical vapor deposition. Subsequently, as the reactor rotates, the deposited product is dispersed through the fluidization holes into the upper portion of the fluidization chamber, where it is fully fluidized. At this point, since the concentration of elemental silicon in the upper portion of the fluidization chamber is higher than at one end of the reactor, any portion of the carbon rack that has not yet completed deposition with elemental silicon can still fully contact and deposit with elemental silicon in the upper portion of the fluidization chamber. The deposited product enters the lower part of the fluidizing chamber directly under the action of gravity, and acetylene and nitrogen are introduced from the lower air inlet. Acetylene is cracked into carbon element and hydrogen by heat. The carbon element is coated on the outside of the deposited product, realizing the carbon coating process and obtaining a silicon negative electrode product; the silicon negative electrode product is discharged from the discharge hole.

[0010] The reactor and fluidizing chamber maintain a high-temperature, low-oxygen environment. The two devices complement each other, ensuring that no or only a small amount of air is introduced during the production process, keeping the internal oxygen content below 5ppm. Feeding the material through the carbon rack feeder also ensures that no or only a small amount of oxygen enters the carbon rack feeder. This allows for continuous, non-stop production of silicon anode products in the reactor and fluidizing chamber, increasing silicon anode yield, reducing production costs, and enabling large-scale production of silicon anodes.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the silicon negative electrode CVD and carbon coating equipment also includes an end feed barrel, one end of which is fixedly arranged outside the fluidizing chamber and has an end feed port, and the other end of the reactor is rotatably connected to the other end of the end feed barrel.

[0013] The beneficial effect of adopting the above further solution is that monosilane and nitrogen can be introduced from the other end of the reactor through the end feeding cylinder, thereby increasing the introduction efficiency of monosilane and improving the output.

[0014] Furthermore, the silicon negative electrode CVD and carbon coating equipment also includes a filter, and the exhaust hole, the filter, the exhaust fan and the upper part of the fluidizing chamber are connected in sequence through a pipeline.

[0015] The beneficial effect of adopting the above further solution is: a filter is provided at the inlet of the exhaust fan to prevent the carbon rack or the deposited product from entering the exhaust fan, so that the carbon rack or the deposited product can only be discharged from the fluidizing hole.

[0016] Furthermore, the silicon negative electrode CVD and carbon coating equipment further includes an upper circulation component and a lower circulation component, wherein the upper circulation component includes a first heat exchanger, a first dehydrogenator, and a first induced draft fan connected in sequence, and the inlet of the first heat exchanger and the outlet of the first induced draft fan are both connected to the upper part of the fluidizing chamber;

[0017] The lower circulation component includes a second heat exchanger, a second dehydrogenator, and a second induced draft fan which are connected in sequence. The inlet of the second heat exchanger and the outlet of the second induced draft fan are both connected to the lower part of the fluidizing chamber.

[0018] The beneficial effect of adopting the above further scheme is: an upper circulation component and a lower circulation component are respectively set at the upper and lower parts of the fluidizing chamber, and the upper and lower gases of the fluidizing chamber are respectively extracted, and the hydrogen in the gas is removed and then sent back to the fluidizing chamber for reuse.

[0019] Furthermore, the silicon negative electrode CVD and carbon coating equipment also includes a high-temperature fan, an air distribution plate and a discharge pipe. The bottom of the fluidizing chamber is provided with an air distribution chamber. The air inlet of the high-temperature fan is connected to the lower part of the fluidizing chamber, and the air outlet of the high-temperature fan is connected to the air distribution chamber. The air distribution plate is fixed on the top of the air distribution chamber. The discharge pipe is vertically arranged, passes through the air distribution plate and is fixedly connected to the air distribution plate. The discharge pipe has the discharge hole.

[0020] The beneficial effect of adopting the above further solution is that the high-temperature fan blows air from bottom to top into the fluidizing chamber through the air distribution plate, stirring the gas in the lower part of the fluidizing chamber and making the carbon coating reaction uniform. The silicon negative electrode product is discharged from the discharge pipe.

[0021] Furthermore, the silicon negative electrode CVD and carbon coating equipment also includes a discharge augers, and the discharge augers are connected to the discharge hole.

[0022] The beneficial effect of adopting the above further scheme is: the discharging auger discharges the silicon negative electrode product, and the auger is used for feeding. The silicon negative electrode product and the auger blades can be used to prevent external air from entering the fluidization chamber, isolating oxygen and ensuring the safety of the production process.

[0023] Furthermore, the heaters are provided in two groups, one group of heaters is provided in the middle of the fluidizing chamber and divides the fluidizing chamber into an upper fluidizing chamber located at its upper part and a lower fluidizing chamber located at its lower part, and the other group of heaters is provided at the bottom of the fluidizing chamber.

[0024] The beneficial effect of adopting the above further solution is: the heater is used to naturally divide the fluidizing chamber into two interconnected chambers, which can not only fully heat the fluidizing chamber, but also simplify the structure of the fluidizing chamber itself, without the need for additional processing of partitions and other structures in the fluidizing chamber.

[0025] Furthermore, the heater is an electric heater, the heater is annular, and the heater has an inverted conical guide hole.

[0026] The beneficial effect of adopting this further solution is that the guide hole is funnel-shaped, which is used to converge the material and gradually flow it into the lower fluidizing chamber, allowing the material to have sufficient residence time in the upper fluidizing chamber and slowing its rate of descent into the lower fluidizing chamber, thereby giving the material sufficient reaction time in both the upper and lower fluidizing chambers. The heater is an electric heater using a resistance wire, which can heat in anoxic conditions, avoiding the introduction of oxygen and the risk of explosion caused by combustion heating, and helping to control the oxygen content in the fluidizing chamber to below 5ppm.

[0027] Furthermore, the carbon rack feeding device includes a front end feed barrel, a pushing hydraulic cylinder and an air outlet barrel. The front end feed barrel is fixedly arranged, the pushing hydraulic cylinder is fixed in one end of the front end feed barrel, the middle part of the front end feed barrel has a front end feed port, the air outlet barrel is fixedly arranged and sleeved on the outside of the front end feed barrel, one end of the reactor is rotatably connected to the air outlet barrel, and is connected to the other end of the front end feed barrel and the air outlet barrel, and the end of the air outlet barrel located outside the reactor has the exhaust hole.

[0028] The beneficial effect of this further solution is that the carbon rack is fed into the front feed barrel through the front feed port, and the hydraulic cylinder pushes the carbon rack in the front feed barrel into the reactor. While feeding, the carbon rack also forms a seal with the front feed barrel, reducing the introduction of air during feeding. Gas in the reactor is discharged through the exhaust pipe and returned to the fluidizing chamber under the power of the exhaust fan.

[0029] The present invention also provides a method for continuous mass production of silicon negative electrode CVD and carbon coating, which is implemented using the silicon negative electrode CVD and carbon coating equipment, and includes the following steps:

[0030] A porous carbon frame is fed into the reactor through a carbon frame feeding device;

[0031] At the same time, the heater heats the fluidization chamber to 800-900 degrees Celsius, and monosilane and nitrogen are introduced from the upper air inlet. The monosilane is thermally cracked into silicon and hydrogen. Under the power of the exhaust fan, the silicon enters the reactor through the fluidization hole and contacts the carbon frame in countercurrent flow, thereby being deposited in the porous structure of the carbon frame to obtain a deposited product.

[0032] As the reactor rotates, the deposited product is scattered into the fluidization chamber through the fluidization holes. The deposited product is fully fluidized and falls to the lower part of the fluidization chamber under its own gravity. At the same time, the silicon element, nitrogen and hydrogen in the reactor return to the fluidization chamber under the power of the exhaust fan. Acetylene and nitrogen are introduced from the lower air inlet. The acetylene is thermally cracked into carbon element and hydrogen. The carbon element is coated on the outside of the deposited product to obtain a silicon negative electrode product.

[0033] The silicon negative electrode product is discharged from the discharge hole.

[0034] The beneficial effect is: using the reactor and fluidizing chamber that cooperate with each other to realize the two processes of silicon negative electrode CVD and carbon coating, silicon negative electrode products can be produced continuously without stopping, which increases the output of silicon negative electrode, reduces production costs, and enables silicon negative electrode to be produced and used on a large scale.

[0035] Furthermore, the continuous mass production method of silicon negative electrode CVD and carbon coating also includes: a high-temperature fan causes the gas in the lower part of the fluidizing chamber to flow from bottom to top through an air distribution plate, so that the carbon element is in full contact with the deposited product.

[0036] The beneficial effect of adopting the above further solution is that the high-temperature fan blows air from bottom to top into the fluidizing chamber through the air distribution plate, stirring the gas in the lower part of the fluidizing chamber and making the carbon coating reaction uniform. The silicon negative electrode product is discharged from the discharge pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic structural diagram of the silicon negative electrode CVD and carbon coating equipment of the present invention;

[0038] Figure 2 Schematic diagram of the material flow direction of the silicon negative electrode CVD and carbon coating equipment of the present invention.

[0039] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0040] 1. Carbon rack feeding device; 101. Feed hopper; 102. Pushing hydraulic cylinder; 103. Exhaust pipe;

[0041] 2. Reactor; 201. Fluidizing hole; 202. Extension tube; 203. End feeding tube;

[0042] 3. Fluidizing chamber; 301. Upper air inlet; 302. Lower air inlet; 303. Upper fluidizing chamber; 304. Lower fluidizing chamber;

[0043] 4. Heater; 5. High-temperature fan; 6. Air distribution plate; 7. Discharge auger; 8. Filter; 9. Exhaust fan;

[0044] 10. Upper circulation component; 1001. First heat exchanger; 1002. First dehydrogenator; 1003. First induced draft fan;

[0045] 11. Lower circulation component; 1101. Second heat exchanger; 1102. Second dehydrogenator; 1103. Second induced draft fan. DETAILED DESCRIPTION

[0046] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0047] Example 1

[0048] like Figure 1-Figure 2As shown, this embodiment provides a silicon negative electrode CVD and carbon coating equipment, including a carbon frame feeding device 1, a reactor 2, a fluidizing chamber 3, a heater 4 and an exhaust fan 9, one end of the reactor 2 is rotatably connected and communicated with the carbon frame feeding device 1, and the other end thereof extends into the fluidizing chamber 3 and is rotatably connected to the upper part of the fluidizing chamber 3, the side wall of the other end of the reactor 2 has a plurality of fluidizing holes 201, and one end of the reactor 2 is also provided with an exhaust hole, and the exhaust hole is communicated with the upper part of the fluidizing chamber 3 through the exhaust fan 9, the upper part of the fluidizing chamber 3 has an upper air inlet 301, and the upper air inlet 301 is used to introduce monosilane and nitrogen, the lower part of the fluidizing chamber 3 has a lower air inlet 302, and the lower air inlet 302 is used to introduce acetylene and nitrogen, the bottom of the fluidizing chamber 3 has a discharge hole, and the heater 4 is fixedly connected to the inner wall of the fluidizing chamber 3.

[0049] In this embodiment, a porous carbon rack is fed into reactor 2 via a carbon rack feeder 1. A heater 4 creates a high-temperature environment within fluidizing chamber 3, introducing monosilane (SiH4) and nitrogen (N2) through upper gas inlet 301. The monosilane is thermally cracked into elemental silicon (Si) and hydrogen (H2). A blower 9 provides power, allowing the gas and elemental silicon in the upper portion of fluidizing chamber 3 to enter reactor 2 through fluidizing holes 201 and then return to fluidizing chamber 3 through the gas extraction holes. The elemental silicon and carbon rack interact in countercurrent flow within reactor 2, ensuring sufficient contact. The silicon is deposited within the pores of the carbon rack, forming a deposited product, thereby achieving chemical vapor deposition. Powered by blower 9, the silicon, nitrogen, and hydrogen in reactor 2 are returned to fluidizing chamber 3, recycling the elemental silicon and improving monosilane utilization. Subsequently, as reactor 2 rotates, the deposited product is dispersed from fluidizing holes 201 into the upper portion of fluidizing chamber 3, where it is fully fluidized. At this point, because the silicon concentration in the upper portion of fluidizing chamber 3 is higher than at one end of reactor 2, any carbon racks that have not yet completed deposition with silicon can still fully contact and deposit silicon in the upper portion of fluidizing chamber 3. The deposited product, under the action of gravity, enters the lower portion of fluidizing chamber 3 directly. Acetylene (C2H2) and nitrogen (N2) are introduced through lower gas inlet 302. The acetylene is thermally cracked into carbon (C) and hydrogen (H2). The carbon coats the outside of the deposited product, completing the carbon coating process and producing a silicon anode product. The silicon anode product is then discharged through the discharge port.

[0050] Reactor 2 and fluidizing chamber 3 create a high-temperature, low-oxygen environment. The two devices complement each other, allowing for the introduction of only a small amount of air or no external air during production, keeping the internal oxygen content below 5 ppm. Feeding through the carbon rack feeder 1 also ensures that only a small amount of oxygen enters the carbon rack feeder 1. This allows for continuous, non-stop production of silicon anode products in reactor 2 and fluidizing chamber 3, increasing silicon anode yield, reducing production costs, and enabling large-scale production of silicon anodes.

[0051] Specifically, the sidewall of reactor 2 outside fluidizing chamber 3 is wrapped with an insulation layer to reduce heat loss. A spiral guide plate is fixed to the inner wall of reactor 2, or multiple guide plates are spaced along the spiral direction. As reactor 2 rotates, the guide plate pushes the carbon rack toward fluidizing hole 201.

[0052] Specifically, among the monosilane and nitrogen gases introduced through the upper gas inlet 301 , the volume ratio of monosilane to all gases introduced through the upper gas inlet 301 is less than or equal to 1%.

[0053] Optionally, the reactor 2 is cylindrical, or the reactor 2 is conical with a diameter at one end being larger than that at the other end, that is, the diameter at the end close to the carbon rack feeding device 1 is larger.

[0054] Specifically, the outer wall of reactor 2 is sheathed with a coaxial external gear. A motor is mounted on the frame, and a drive gear is attached to the motor's output shaft. The drive gear meshes with the external gear, driving reactor 2 to rotate about its own axis. Rollers are located on both sides of the lower portion of reactor 2. The axes of these rollers are parallel to the axis of reactor 2 and are rotatably mounted on the frame. The rollers abut against the outer wall of reactor 2, providing support. Multiple sets of rollers are spaced along the axial direction of reactor 2.

[0055] Based on the above technical solution, the silicon negative electrode CVD and carbon coating equipment also includes an end feed barrel 203, one end of which is fixedly arranged outside the fluidizing chamber 3 and has an end feed port, and the other end of the reactor 2 is rotatably connected to the other end of the end feed barrel 203.

[0056] Monosilane and nitrogen can be introduced from the other end of the reactor 2 through the end feeding cylinder 203, thereby increasing the efficiency of monosilane introduction and improving the output.

[0057] Specifically, the end feed port is used to introduce monosilane and nitrogen. Preferably, the end feed port and the upper air inlet 301 are both connected to the first air supply pipeline, and the first air supply pipeline is used to transport monosilane and nitrogen.

[0058] Furthermore, an extension tube 202 is fixed to and connected to the other end of the reactor 2. The diameter of the extension tube 202 is smaller than that of the other end of the reactor 2. The extension tube 202 extends out of the fluidizing chamber 3 and is rotatably connected to the other end of the end feed tube 203. The diameter of the end feed tube 203 is smaller than that of the extension tube 202. This gradually decreasing diameter structure can reduce heat loss to a certain extent. Preferably, a pair of rollers are provided below the portion of the extension tube 202 located outside the fluidizing chamber 3 to support the extension tube 202.

[0059] On the basis of the above technical solution, the silicon negative electrode CVD and carbon coating equipment further includes a filter 8, and the exhaust hole, the filter 8, the exhaust fan 9 and the upper part of the fluidizing chamber 3 are connected in sequence through pipelines.

[0060] A filter 8 is provided at the inlet of the exhaust fan 9 to prevent the carbon rack or deposited products from entering the exhaust fan 9 so that they can only be discharged from the fluidization hole 201 .

[0061] Specifically, the mesh diameter of the filter 8 is smaller than the diameter of the carbon frame and larger than the particle size of the silicon element generated in the fluidizing chamber 3 .

[0062] On the basis of the above technical solution, the silicon negative electrode CVD and carbon coating equipment further includes an upper circulation component 10 and a lower circulation component 11, wherein the upper circulation component 10 includes a first heat exchanger 1001, a first dehydrogenator 1002 and a first induced draft fan 1003 connected in sequence, and the inlet of the first heat exchanger 1001 and the outlet of the first induced draft fan 1003 are both connected to the upper part of the fluidizing chamber 3;

[0063] The lower circulation component 11 includes a second heat exchanger 1101, a second dehydrogenator 1102 and a second induced draft fan 1103 which are connected in sequence. The inlet of the second heat exchanger 1101 and the outlet of the second induced draft fan 1103 are both connected to the lower part of the fluidizing chamber 3.

[0064] An upper circulation assembly 10 and a lower circulation assembly 11 are respectively provided at the upper and lower parts of the fluidizing chamber 3 to extract the gas from the upper and lower parts of the fluidizing chamber 3, remove the hydrogen in the gas and return it to the fluidizing chamber 3 for reuse.

[0065] Specifically, silane and acetylene can be cracked as soon as they enter the fluidizing chamber 3. After the reaction, H2 is left in the upper and lower parts of the fluidizing chamber 3. The air flow in the upper part of the fluidizing chamber 3 (upper fluidizing chamber 303) includes silicon element (a solid that can flow with the gas), hydrogen and nitrogen, and the air flow in the lower part of the fluidizing chamber 3 (lower fluidizing chamber 304) includes carbon element, hydrogen and nitrogen. Therefore, the air flow in the upper fluidizing chamber 303 and the lower fluidizing chamber 304 can be reused after removing the hydrogen.

[0066] Among them, the first heat exchanger 1001 of the upper circulation component 10 is used to cool the air flow extracted from the upper fluidizing chamber 303. After the second dehydrogenator 1102 removes hydrogen from the air flow in the upper fluidizing chamber 303, it is sent back to the upper fluidizing chamber 303 by the first induced draft fan 1003.

[0067] Among them, the second heat exchanger 1101 of the lower circulation component 11 is used to cool the air flow extracted from the lower fluidizing chamber 304. After the second dehydrogenator 1102 removes hydrogen in the air flow of the lower fluidizing chamber 304, the second induced draft fan 1103 returns it to the lower fluidizing chamber 304.

[0068] The first dehydrogenator 1002 and the second dehydrogenator 1102 may be low-temperature catalytic oxidation reactors filled with catalysts (eg, Pd / Al2O3) to oxidize hydrogen into water.

[0069] On the basis of the above technical solution, the silicon negative electrode CVD and carbon coating equipment also includes a high-temperature fan 5, an air distribution plate 6 and a discharge pipe. The bottom of the fluidizing chamber 3 is provided with an air distribution chamber, the air inlet of the high-temperature fan 5 is connected to the lower part of the fluidizing chamber 3, and the air outlet of the high-temperature fan 5 is connected to the air distribution chamber. The air distribution plate 6 is fixed on the top of the air distribution chamber. The discharge pipe is vertically arranged, passes through the air distribution plate 6 and is fixedly connected to the air distribution plate 6, and the discharge pipe has the discharge hole.

[0070] The high-temperature blower 5 blows air from bottom to top into the fluidizing chamber 3 through the air distribution plate 6, stirring the gas in the lower part of the fluidizing chamber 3 to make the carbon coating reaction uniform. The silicon negative electrode product is discharged from the discharge pipe.

[0071] Optionally, one or more discharge pipes may be provided.

[0072] Specifically, the air distribution plate 6 is an air distribution plate with a hood. The air distribution plate 6 is plate-shaped and has a number of through holes. Each through hole is provided with a hood. The hood has multiple air holes with different angles. If the silicon negative electrode product falls on the air distribution plate 6, it will be blown up and fluidized again until the silicon negative electrode product falls into the discharge pipe and is discharged.

[0073] On the basis of the above technical solution, the silicon negative electrode CVD and carbon coating equipment further includes a discharge agitator 7, and the discharge agitator 7 is connected to the discharge hole.

[0074] The discharging auger 7 discharges the silicon negative electrode product. By using the auger to feed the material, the silicon negative electrode product and the auger blades can be used to prevent external air from entering the fluidizing chamber 3, isolating oxygen and ensuring the safety of the production process.

[0075] Specifically, the lower end of the discharge pipe passes through the air distribution chamber and is connected to the feed port of the discharge auger 7.

[0076] Based on the above technical solution, the heater 4 is provided with two groups, one group of the heaters 4 is arranged in the middle of the fluidizing chamber 3, and the fluidizing chamber 3 is divided into an upper fluidizing chamber 303 located at the upper part and a lower fluidizing chamber 304 located at the lower part; the other group of the heaters 4 is arranged at the bottom of the fluidizing chamber 3.

[0077] The heater 4 is used to naturally divide the fluidizing chamber 3 into two interconnected chambers, which can fully heat the fluidizing chamber 3 and simplify the structure of the fluidizing chamber 3 itself, without the need to additionally process structures such as partitions in the fluidizing chamber 3.

[0078] Specifically, the other end of the reactor 2 , the upper air inlet 301 and the upper circulation assembly 10 are all located in the upper fluidizing chamber 303 ; the lower air inlet 302 is located in the lower fluidizing chamber 304 .

[0079] On the basis of the above technical solution, the heater 4 is an electric heater, the heater 4 is annular, and the heater 4 has an inverted conical guide hole.

[0080] The funnel-shaped guide hole is used to converge the material and gradually flow it into the lower fluidizing chamber 304, allowing the material to remain in the upper fluidizing chamber 303 for a sufficient period of time while slowing its rate of descent into the lower fluidizing chamber 304. This allows the material to have sufficient reaction time in both the upper and lower fluidizing chambers 303 and 304. Heater 4 is an electric heater using a resistance wire for heating, enabling anaerobic heating. This avoids the introduction of oxygen and the risk of explosion caused by combustion heating, thus helping to control the oxygen content in fluidizing chamber 3 to below 5 ppm.

[0081] In one specific example, Figure 1 As shown, the heater 4 is in the shape of a ring with a right triangle in longitudinal section. Alternatively, in another example, the heater 4 is in the shape of a ring with a right trapezoid in longitudinal section.

[0082] Preferably, the outer surface of the heater 4 is wrapped with an insulating layer to avoid the risk of explosion caused by static electricity or electric sparks.

[0083] On the basis of the above technical solution, the carbon rack feeding device 1 includes a front end feed barrel, a pushing hydraulic cylinder 102 and an air outlet barrel 103. The front end feed barrel is fixedly arranged, and the pushing hydraulic cylinder 102 is fixed in one end of the front end feed barrel. The middle part of the front end feed barrel has a front end feed port, and the air outlet barrel 103 is fixedly arranged and sleeved on the outside of the front end feed barrel. One end of the reactor 2 is rotatably connected to the air outlet barrel 103, and is connected to the other end of the front end feed barrel and the air outlet barrel 103. The air outlet barrel 103 has the exhaust hole at one end outside the reactor 2.

[0084] The carbon rack is fed into the front feed barrel through the front feed port. A hydraulic pusher cylinder 102 delivers the carbon rack from the front feed barrel into reactor 2. While feeding, the carbon rack also forms a seal with the front feed barrel, minimizing the introduction of air during feeding. Gas within reactor 2 is drawn out through an exhaust pipe 103 and returned to fluidizing chamber 3 under the power of exhaust fan 9.

[0085] Specifically, a feed hopper 101 is fixed on the front feed port, and materials are fed into the front feed cylinder through the feed hopper 101.

[0086] Alternatively, the carbon rack feeding device 1 is a feeding auger, and the use of the auger for feeding can also prevent external air from entering the reactor 2.

[0087] Based on the above technical solution, the sidewall of the lower portion of fluidizing chamber 3 (lower fluidizing chamber 304) also has an exhaust gas outlet. The silicon anode CVD and carbon coating equipment are purged with nitrogen before use. After purging, excess nitrogen in fluidizing chamber 3 can be discharged through the exhaust gas outlet. Suitable gas purification equipment can also be installed outside the exhaust gas outlet as needed. The exhaust gas outlet is equipped with an exhaust valve for opening and closing.

[0088] Example 2

[0089] This embodiment also provides a method for continuous mass production of silicon negative electrode CVD and carbon coating, which is implemented using the silicon negative electrode CVD and carbon coating equipment, including the following steps:

[0090] A porous carbon frame is fed into the reactor 2 through the carbon frame feeding device 1;

[0091] Simultaneously, heater 4 heats the fluidizing chamber 3 to 800-900 degrees Celsius. Monosilane and nitrogen are introduced through the upper air inlet 301. The monosilane is thermally cracked into silicon and hydrogen. Powered by exhaust fan 9, the silicon enters reactor 2 through fluidizing holes 201 and countercurrently contacts the carbon frame, where it is deposited within the porous structure of the carbon frame, yielding a deposited product.

[0092] As the reactor 2 rotates, the deposited product is sprinkled into the fluidizing chamber 3 through the fluidizing holes 201. The deposited product is fully fluidized and falls to the lower part of the fluidizing chamber 3 under its own gravity. At the same time, the silicon element, nitrogen, and hydrogen in the reactor 2 return to the fluidizing chamber 3 under the power of the exhaust fan 9. Acetylene and nitrogen are introduced from the lower air inlet 302. The acetylene is thermally cracked into carbon element and hydrogen. The carbon element is coated on the outside of the deposited product to obtain a silicon negative electrode product.

[0093] The silicon negative electrode product is discharged from the discharge hole.

[0094] The beneficial effects of this embodiment are: the two processes of silicon negative electrode CVD and carbon coating are realized by using the reactor 2 and fluidizing chamber 3 that cooperate with each other, and the silicon negative electrode products can be produced continuously without stopping, thereby increasing the output of silicon negative electrodes, reducing production costs, and enabling silicon negative electrodes to be produced and used on a large scale.

[0095] Specifically, before using the silicon anode CVD and carbon coating equipment, the following steps are performed: nitrogen is introduced through the upper air inlet 301 and / or the lower air inlet 302; the high-temperature blower 5, the exhaust fan 9, the first induced draft fan 1003, and the second induced draft fan 1103 are activated; nitrogen is then used to purge the interior of the silicon anode CVD and carbon coating equipment, filling the reactor 2, the fluidizing chamber 3, and all pipelines with nitrogen to ensure an oxygen content of less than 5 ppm. Excess gas is then removed from the interior and discharged through the exhaust port at the bottom of the fluidizing chamber 3.

[0096] Based on the above technical solution, the continuous mass production method of silicon negative electrode CVD and carbon coating also includes: the high-temperature fan 5 makes the gas in the lower part of the fluidizing chamber 3 flow from bottom to top through the air distribution plate 6, so that the carbon element is in full contact with the deposited product.

[0097] The high-temperature blower 5 blows air from bottom to top into the fluidizing chamber 3 through the air distribution plate 6, stirring the gas in the lower part of the fluidizing chamber 3 to make the carbon coating reaction uniform. The silicon negative electrode product is discharged from the discharge pipe.

[0098] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0099] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0100] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0101] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0102] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Silicon anode CVD and carbon coating equipment, characterized in that, The invention comprises a carbon frame feeding device (1), a reactor (2), a fluidizing chamber (3), a heater (4) and an exhaust fan (9), wherein one end of the reactor (2) is rotatably connected and communicated with the carbon frame feeding device (1), and the other end thereof extends into the fluidizing chamber (3) and is rotatably connected with the upper part of the fluidizing chamber (3), and the side wall of the other end of the reactor (2) has a plurality of fluidizing holes (201), and one end of the reactor (2) is also provided with an exhaust hole, and the exhaust hole is communicated with the upper part of the fluidizing chamber (3) through the exhaust fan (9), and the upper part of the fluidizing chamber (3) has an upper air inlet (301), and the upper air inlet (301) is used to introduce monosilane and nitrogen. ) has a lower air inlet (302) at its lower portion, the lower air inlet (302) being used to introduce acetylene and nitrogen, the bottom of the fluidizing chamber (3) having a discharge hole, the heater (4) being fixedly connected to the inner wall of the fluidizing chamber (3); the heater (4) being provided with two groups, one group of the heaters (4) being provided in the middle of the fluidizing chamber (3) and dividing the fluidizing chamber (3) into an upper fluidizing chamber (303) located at its upper portion and a lower fluidizing chamber (304) located at its lower portion, and the other group of the heaters (4) being provided at the bottom of the fluidizing chamber (3); the heater (4) being an electric heater, the heater (4) being annular, and the heater (4) having an inverted conical guide hole.

2. The silicon negative electrode CVD and carbon coating equipment according to claim 1, characterized in that: It also includes an end feed cylinder (203), one end of which is fixedly arranged outside the fluidizing chamber (3) and has an end feed port, and the other end of the reactor (2) is rotatably connected to the other end of the end feed cylinder (203).

3. The silicon negative electrode CVD and carbon coating equipment according to claim 1, characterized in that: It also includes a filter (8), and the air extraction hole, the filter (8), the exhaust fan (9) and the upper part of the fluidizing chamber (3) are connected in sequence through a pipeline.

4. The silicon negative electrode CVD and carbon coating equipment according to claim 1, characterized in that: It also includes an upper circulation component (10) and a lower circulation component (11), wherein the upper circulation component (10) includes a first heat exchanger (1001), a first dehydrogenator (1002), and a first induced draft fan (1003) that are connected in sequence, and the inlet of the first heat exchanger (1001) and the outlet of the first induced draft fan (1003) are both connected to the upper part of the fluidizing chamber (3); The lower circulation component (11) comprises a second heat exchanger (1101), a second dehydrogenator (1102) and a second induced draft fan (1103) which are connected in sequence, and an inlet of the second heat exchanger (1101) and an outlet of the second induced draft fan (1103) are both connected to the lower part of the fluidizing chamber (3).

5. The silicon negative electrode CVD and carbon coating equipment according to claim 1, characterized in that: It also includes a high-temperature fan (5), an air distribution plate (6) and a discharge pipe. The bottom of the fluidizing chamber (3) is provided with an air distribution chamber. The air inlet of the high-temperature fan (5) is communicated with the lower part of the fluidizing chamber (3), and the air outlet of the high-temperature fan (5) is communicated with the air distribution chamber. The air distribution plate (6) is fixed on the top of the air distribution chamber. The discharge pipe is vertically arranged, passes through the air distribution plate (6) and is fixedly connected to the air distribution plate (6), and the discharge pipe has the discharge hole.

6. The silicon negative electrode CVD and carbon coating equipment according to claim 1, characterized in that: It also includes a discharge augers (7), and the discharge augers (7) are connected to the discharge hole.

7. The silicon negative electrode CVD and carbon coating equipment according to any one of claims 1 to 6, characterized in that: The carbon rack feeding device (1) includes a front-end feeding barrel, a pushing hydraulic cylinder (102) and an air outlet barrel (103), wherein the front-end feeding barrel is fixedly arranged, the pushing hydraulic cylinder (102) is fixed inside one end of the front-end feeding barrel, the middle part of the front-end feeding barrel has a front-end feeding port, the air outlet barrel (103) is fixedly arranged and sleeved on the outside of the front-end feeding barrel, one end of the reactor (2) is rotatably connected to the air outlet barrel (103), and is communicated with the other end of the front-end feeding barrel and the air outlet barrel (103), and the air outlet barrel (103) has the air extraction hole at one end outside the reactor (2).

8. A method for continuous mass production of silicon negative electrode CVD and carbon coating, characterized in that: The method is implemented using the silicon negative electrode CVD and carbon coating equipment according to any one of claims 1 to 7, comprising the following steps: A porous carbon frame is fed into the reactor (2) through a carbon frame feeding device (1); At the same time, the heater (4) heats the fluidization chamber (3) to 800-900 degrees Celsius, and monosilane and nitrogen are introduced from the upper air inlet (301). The monosilane is thermally cracked into silicon and hydrogen. Under the power of the exhaust fan (9), the silicon enters the reactor (2) from the fluidization hole (201) and contacts the carbon frame in countercurrent flow, thereby being deposited in the porous structure of the carbon frame to obtain a deposited product. As the reactor (2) rotates, the deposited product is scattered into the fluidizing chamber (3) through the fluidizing hole (201), the deposited product is fully fluidized, and falls into the lower part of the fluidizing chamber (3) under the action of its own gravity; at the same time, the silicon element, nitrogen and hydrogen in the reactor (2) return to the fluidizing chamber (3) under the power of the exhaust fan (9); acetylene and nitrogen are introduced from the lower air inlet (302), and the acetylene is thermally cracked into carbon element and hydrogen, and the carbon element is coated on the outside of the deposited product to obtain a silicon negative electrode product; The silicon negative electrode product is discharged from the discharge hole.

9. The method for continuous mass production of silicon negative electrode CVD and carbon coating according to claim 8, characterized in that: Also includes: The high-temperature fan (5) causes the gas in the lower part of the fluidizing chamber (3) to flow from bottom to top through the air distribution plate (6), so that the carbon element is fully in contact with the deposited product.

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