Continuous silicon-carbon negative electrode production process and equipment thereof

Abstract

The invention discloses a continuous silicon-carbon negative electrode production process and equipment thereof, and relates to the technical field of continuous silicon-carbon negative electrode production, purified porous carbon is added from the position of a feeding end, mixed gas composed of SiHCl3 and H2 is added from the position of a gas inlet pipe, and the weight ratio of the porous carbon to the mixed gas is controlled to be (0.2-5): 1; the particle size of the porous carbon is controlled to be 20-100 nm, the feeding amount of the porous carbon per hour is controlled to be 0.5-30% of the area of the furnace tube, and the porous carbon and the mixed gas react at the high-temperature section. According to the continuous silicon-carbon negative electrode production process and equipment provided by the invention, SiHCl3 is adopted to replace silane as a raw material, the process is simple, the lining is arranged on the inner wall of the furnace tube, and the first lifting plate, the second lifting plate and the third lifting plate are arranged on the high-temperature section, so that the retention time of a porous carbon material in the high-temperature section can be prolonged; meanwhile, the contact area of the porous carbon and the mixed gas is enlarged, so that the production reaction efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous silicon-carbon anode production, and specifically to a continuous silicon-carbon anode production process and its equipment. Background Art

[0002] With the development of the fields of electric vehicles and large-scale energy storage, the demand for the energy density of lithium-ion batteries is continuously increasing. The energy density of traditional graphite anode materials has approached its theoretical limit (372 mAh / g), making it difficult to meet the requirements for higher energy density. Silicon, as an anode material, has an extremely high theoretical specific capacity (4200 mAh / g), a low working voltage, and is rich in reserves in the earth's crust, with low cost and environmental friendliness. It is considered to be one of the most promising next-generation lithium-ion battery anode materials.

[0003] However, pure silicon has problems such as large volume expansion (about 300%) and low electronic conductivity during charge and discharge processes, which limit its practical applications. By nano-sizing silicon and compounding it with carbon to prepare silicon-carbon anode materials, these problems can be effectively solved. Carbon materials can not only buffer the volume expansion of silicon but also improve the conductivity and cycle stability of the materials.

[0004] Currently, in the process of large-scale continuous production of silicon-carbon anodes, the following production problems need to be actually solved:

[0005] 1. Most of the existing technologies use silane as raw materials, resulting in high production costs. In the process of large-scale production, it is not conducive to the long-term development of enterprises;

[0006] 2. During the chemical reaction between porous carbon and the mixed gas, it is difficult for the porous carbon to come into full contact with the mixed gas, and the dispersibility of the porous carbon is poor, resulting in difficulty in the good reaction process of the materials;

[0007] 3. The HCl generated by the reactants will cause corrosion when contacting the furnace tube, resulting in a low overall service life of the equipment, which is not conducive to the large-scale continuous production of silicon-carbon anodes by enterprises. Summary of the Invention

[0008] The purpose of the present invention is to address the above problems by providing a continuous silicon-carbon anode production process and its equipment. SiHCl is used 3 to replace silane as the raw material. The process is simple. A bushing is provided on the inner wall of the furnace tube, and the bushing is made of carbon-carbon or carbon-carbon plus graphite material to avoid corrosion by HCl. In the high-temperature section, a first material lifting plate, a second material lifting plate, and a third material lifting plate are provided, which can extend the residence time of the porous carbon material in the high-temperature section and at the same time increase the contact area between the porous carbon and the mixed gas, thereby improving the production reaction efficiency. During the preparation process, natural gas is added, and the hydrogen generated by the materials can be used as SiHCl 3The raw materials for the reaction, and the hydrogen in the mixed gas added simultaneously can be used as a gas to inhibit the cracking of natural gas, promote the formation of a rough layer of carbon from natural gas, and improve the electrical conductivity and thermal conductivity of the carbon produced after the cracking of natural gas.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A continuous silicon-carbon anode production process includes the following production steps:

[0011] Step A: Add purified and purified porous carbon at the feed end position, and add a mixed gas composed of SiHCl 3 and H 2 at the inlet pipe position. The weight ratio of the porous carbon to the mixed gas is controlled to be 0.2 - 5:1; the particle size of the porous carbon is controlled to be 20 - 100 nm, and the hourly input amount of the porous carbon is controlled at 0.5 - 30% of the furnace tube area. The following reaction occurs between the porous carbon and the mixed gas at the high-temperature section position:

[0012]

[0013] Step B: Drive the second motor, and the first lifting plate, the second lifting plate, and the third lifting plate in the high-temperature section position lift the porous carbon at the high-temperature section position, increasing the contact area between the porous carbon and silicon, and making their combination more sufficient.

[0014] As a further improvement of the above solution, the temperature control for feeding the porous carbon and the mixed gas into the inlet pipe position is changed to 18 - 24 °C, and the pressure control is 0.1 - 0.5 MPa.

[0015] As a further improvement of the above solution, natural gas is introduced into the high-temperature section, and the following reaction occurs to natural gas in the high-temperature section:

[0016] C 2 H 2＝ 2C + H 2

[0017] Among them, the generated H 2 is used as the raw material for the reaction of SiHCl 3 .

[0018] An apparatus for a continuous silicon-carbon anode production process includes a machine housing, a furnace tube is arranged inside the machine housing, a lining is arranged on the inner wall of the furnace tube, the lining is made of carbon-carbon or carbon-carbon plus graphite material, a low-temperature section, a high-temperature section, and a slow-cooling section are arranged inside the furnace tube, a first rotating shaft is rotatably arranged in the high-temperature section, and a first lifting plate, a second lifting plate, and a third lifting plate are arranged on the first rotating shaft. One end of the low-temperature section is connected to a feed pipe cylinder, a spiral feed rod is rotatably arranged inside the feed pipe cylinder, and a feed end is arranged at the upper part of the end of the feed pipe cylinder away from the low-temperature section.

[0019] As a further improvement of the above solution, one end of the spiral feeding rod is connected to the output shaft end of the first motor. A first bearing is arranged between one end of the first rotating shaft and the first support seat. A second bearing is arranged between the furnace tube and the feeding tube cylinder. A first cover plate is arranged at one end of the furnace tube.

[0020] As a further improvement of the above solution, a third bearing and a connecting plate are arranged between the furnace tube and the sleeve. A second cover plate is arranged at the end of the sleeve. The driven gear arranged on the outer part of the sleeve by key connection meshes with the driving gear arranged on the second rotating shaft by key connection. The driving pulley arranged on the second rotating shaft is in transmission connection with the driven pulley arranged on the first rotating shaft through a belt.

[0021] As a further improvement of the above solution, one end of the second rotating shaft is rotatably arranged in the second support seat, and the other end of the second rotating shaft is connected to the output shaft end of the second motor.

[0022] As a further improvement of the above solution, the first material lifting plate is in the shape of a rectangular plate, the second material lifting plate is in the shape of an inclined plate, and the third material lifting plate is in the shape of an S-shaped curved plate.

[0023] As a further improvement of the above solution, a plurality of thermometers are arranged on the machine housing. An air outlet pipe is arranged on the side of the machine housing and on the feeding tube cylinder. A control valve is arranged on the air inlet pipe.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] Using SiHCl 3 to replace silane as the raw material, the process is simple. A bushing is arranged on the inner wall of the furnace tube, and the bushing is made of carbon-carbon or carbon-carbon plus graphite material to avoid the corrosion of HCl. The first material lifting plate, the second material lifting plate, and the third material lifting plate are arranged in the high-temperature section, which can extend the residence time of the porous carbon material in the high-temperature section, and at the same time increase the contact area between the porous carbon and the mixed gas, thereby improving the production reaction efficiency. During the preparation process, natural gas is added, and the hydrogen generated by the material can be used as the raw material for the reaction of SiHCl 3 At the same time, the hydrogen in the added mixed gas can be used as the gas to inhibit the cracking of natural gas, promote the formation of a rough layer of carbon by natural gas, and improve the electrical conductivity and thermal conductivity of the carbon produced after the cracking of natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the front view structural schematic diagram of the equipment of the present invention.

[0027] Figure 2 It is the structural schematic diagram at the position of the sleeve of the present invention.

[0028] Figure 3 It is the structural schematic diagram at the position of the second bearing of the present invention.

[0029] The text annotations shown in the figure are as follows: 1. Feed end; 2. First motor; 3. Screw feeding rod; 4. Feeding tube; 5. First support seat; 6. First bearing; 7. First cover plate; 8. Second bearing; 9. Bushing; 10. Furnace tube; 11. First rotating shaft; 12. First material lifting plate; 13. Second material lifting plate; 14. Third material lifting plate; 15. Second support seat; 16. Driving gear; 17. Second rotating shaft; 18. Second motor; 19. Driving pulley; 20. Driven gear; 21. Sleeve; 22. Belt; 23. Driven pulley; 24. Control valve; 25. Inlet pipe; 26. Machine housing; 27. Thermometer; 28. Slow cooling section; 29. High temperature section; 30. Low temperature section; 31. Outlet pipe; 32. Third bearing; 33. Connecting plate; 34. Second cover plate. Detailed implementation mode

[0030] To enable those skilled in the art to better understand the technical solution, the present invention will be described in detail below in combination with embodiments. The description of this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention.

[0031] As Figures 1 - 3 shown, the specific solution of this embodiment is: A continuous silicon carbon negative electrode production process, including the following production steps:

[0032] Step A: Add the purified and purified porous carbon at the position of the feed end 1, and add the mixed gas composed of SiHCl 3 and H 2 at the position of the inlet pipe 25. The weight ratio of the porous carbon to the mixed gas is controlled as: 0.2 - 5:1; the particle size of the porous carbon is controlled at 20 - 100 nm, and the hourly input amount of the porous carbon is controlled at 0.5 - 30% of the area of the furnace tube 10. The following reaction occurs between the porous carbon and the mixed gas at the position of the high temperature section 29:

[0033]

[0034] Step B: Drive the second motor 18, and the first material lifting plate 12, the second material lifting plate 13, and the third material lifting plate 14 in the high temperature section 29 lift the porous carbon at the position of the high temperature section 29 to increase the contact area between the porous carbon and silicon, making their combination more sufficient.

[0035] As a preferred method of the above embodiment, the temperature control of the porous carbon and the mixed gas fed into the position of the inlet pipe 25 is changed to 18 - 24 °C, and the pressure control is 0.1 - 0.5 MPa.

[0036] As a preferred method of the above embodiment, natural gas is introduced into the high temperature section 29, and the following reaction occurs to natural gas in the high temperature section 29:

[0037] C2 H 2＝ 2C + H 2

[0038] Among them, the generated H 2 serves as the raw material for the reaction of SiHCl 3 .

[0039] An apparatus for a continuous silicon-carbon anode production process includes a machine housing 26. A furnace tube 10 is arranged inside the machine housing 26. A bushing 9 is arranged on the inner wall of the furnace tube 10. The bushing 9 is made of carbon-carbon or carbon-carbon plus graphite material. A low-temperature section 30, a high-temperature section 29, and a slow-cooling section 28 are arranged inside the furnace tube 10. A first rotating shaft 11 is rotatably arranged in the high-temperature section 29. First lifting plates 12, second lifting plates 13, and third lifting plates 14 are arranged on the first rotating shaft 11. One end of the low-temperature section 30 is connected to a feeding tube 4. A spiral feeding rod 3 is rotatably arranged inside the feeding tube 4. An inlet end 1 is arranged on the upper part of the end of the feeding tube 4 away from the low-temperature section 30.

[0040] As another specific embodiment of the present application, one end of the spiral feeding rod 3 is connected to the output shaft end of a first motor 2. A first bearing 6 is arranged between one end of the first rotating shaft 11 and a first support seat 5. A second bearing 8 is arranged between the furnace tube 10 and the feeding tube 4. A first cover plate 7 is arranged at one end of the furnace tube 10.

[0041] More specifically, by driving the first motor 2, the spiral feeding rod 3 makes a rotational movement. The material fed from the position of the inlet end 1 is pushed by the spiral feeding rod 3 into the furnace tube 10, and the silicon preparation reaction operation of the porous carbon and the mixed gas occurs at the position of the high-temperature section 29.

[0042] As another specific embodiment of the present application, a third bearing 32 and a connecting plate 33 are arranged between the furnace tube 10 and a sleeve 21. A second cover plate 34 is arranged at the end of the sleeve 21. A driven gear 20 arranged on the outside of the sleeve 21 by key connection meshes with a driving gear 16 arranged on a second rotating shaft 17 by key connection. A driving pulley 19 arranged on the second rotating shaft 17 is in transmission connection with a driven pulley 23 arranged on the first rotating shaft 11 through a belt 22.

[0043] As another specific embodiment of the present application, one end of the second rotating shaft 17 is rotatably arranged in a second support seat 15, and the other end of the second rotating shaft 17 is connected to the output shaft end of a second motor 18.

[0044] More specifically, by driving the second motor 18, the second rotating shaft 17 makes a rotational movement. The driving gear 16 drives the driven gear 20 to rotate, and both the sleeve 21 and the furnace tube 10 make rotational movements, so that the porous carbon material in the low-temperature section 30, the high-temperature section 29, and the slow-cooling section 28 can fully contact the mixed gas, and at the same time prevent the porous carbon material from caking and accumulating, thereby greatly promoting the reaction efficiency.

[0045] As another specific embodiment of the present application, the first material lifting plate 12 has a rectangular plate structure, the second material lifting plate 13 has an inclined plate structure, and the third material lifting plate 14 has an S-shaped curved plate structure.

[0046] As another specific embodiment of the present application, the first material lifting plate 12 has a rectangular plate structure, the second material lifting plate 13 has an inclined plate structure, and the third material lifting plate 14 has an S-shaped curved plate structure. When the first rotating shaft 11 makes a rotational motion, it can stir the porous carbon material in the furnace tube 10 irregularly, thereby greatly extending the residence time of the porous carbon material in the furnace tube 10 and further promoting the efficiency of the reaction to generate silicon.

[0047] As another specific embodiment of the present application, a plurality of thermometers 27 are provided on the machine housing 26, an air outlet pipe 31 is provided on the side of the machine housing 26 and on the feeding pipe cylinder 4, and a control valve 24 is provided on the air inlet pipe 25.

[0048] More specifically, the control valve 24 is used to control the on-off operation of the air inlet pipe 25.

[0049] The specific working principle of the device of the present invention:

[0050] Drive the first motor 2, and the spiral feeding rod 3 makes a rotational motion. The material fed from the feeding end 1 position is pushed by the spiral feeding rod 3 into the furnace tube 10. The preparation reaction operation of silicon occurs at the high-temperature section 29 where the porous carbon and the mixed gas are located. Drive the second motor 18, and the second rotating shaft 17 makes a rotational motion. The driving gear 16 drives the driven gear 20 to rotate, and both the sleeve 21 and the furnace tube 10 make rotational motions, so that the porous carbon material in the low-temperature section 30, the high-temperature section 29, and the slow-cooling section 28 can fully contact the mixed gas, while preventing the porous carbon material from caking and accumulating, thereby greatly promoting the reaction efficiency. The first material lifting plate 12 has a rectangular plate structure, the second material lifting plate 13 has an inclined plate structure, and the third material lifting plate 14 has an S-shaped curved plate structure. When the first rotating shaft 11 makes a rotational motion, it can stir the porous carbon material in the furnace tube 10 irregularly, thereby greatly extending the residence time of the porous carbon material in the furnace tube 10 and further promoting the efficiency of the reaction to generate silicon.

[0051] It should be noted that in this article, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such a process, method, article or device. Specific examples are used in this article to elaborate on the principles and implementation manners of the technical solution of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention. The above is only the preferred implementation manner of the present invention. It should be pointed out that due to the limited nature of written expression and the objectively infinite specific structures, for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should all be regarded as the protection scope of the present invention.

Claims

1. A continuous silicon-carbon negative electrode production process, characterized in that: The production process includes the following steps: Step A: adding the purified and cleaned porous carbon from the feed end (1), adding the mixed gas composed of SiHCl3 and H2 from the inlet pipe (25), the weight ratio of the porous carbon to the mixed gas is controlled to be: 0.2-5:1; the particle size of the porous carbon is controlled to be 20-100nm, the amount of porous carbon entering per hour is controlled to be 0.5-30% of the area of ​​the furnace tube (10), and the porous carbon and the mixed gas undergo the following reaction at the high temperature section (29): Step B: driving the second motor (18), the first lifting plate (12), the second lifting plate (13), and the third lifting plate (14) in the high temperature section (29) to lift the porous carbon in the high temperature section (29) to increase the contact area between the porous carbon and silicon, thereby making the combination more complete.

2. A continuous silicon-carbon negative electrode production process according to claim 1, characterized in that: The temperature control at the position where the porous carbon and the mixed gas are fed into the air inlet pipe (25) is changed to 18-24°C, and the pressure is controlled to 0.1-0.5MPa.

3. A continuous silicon-carbon negative electrode production process according to claim 1, characterized in that: Natural gas is introduced into the high temperature section (29), and the natural gas undergoes the following reactions in the high temperature section (29): C2H 2＝ 2C+H2 Among them, the generated H2 is used as the raw material for the reaction of SiHCl3.

4. An apparatus for the continuous silicon-carbon negative electrode production process according to claim 1, characterized in that: The invention comprises a machine casing (26), a furnace tube (10) is arranged in the machine casing (26), a bushing (9) is arranged on the inner wall of the furnace tube (10), a low temperature section (30), a high temperature section (29), and a slow cooling section (28) are arranged inside the furnace tube (10), a first rotating shaft (11) is rotatably arranged in the high temperature section (29), a first material lifting plate (12), a second material lifting plate (13), and a third material lifting plate (14) are arranged on the first rotating shaft (11), one end of the low temperature section (30) is connected to a feeding tube (4), a spiral feeding rod (3) is rotatably arranged in the feeding tube (4), and a feeding end (1) is arranged on the upper part of one end of the feeding tube (4) away from the low temperature section (30).

5. The equipment in the continuous silicon-carbon negative electrode production process according to claim 4 is characterized in that: One end of the spiral feeding rod (3) is connected to the output shaft end of the first motor (2), a first bearing (6) is arranged between one end of the first rotating shaft (11) and the first supporting seat (5), a second bearing (8) is arranged between the furnace tube (10) and the feeding tube (4), and a first cover plate (7) is arranged at one end of the furnace tube (10).

6. The equipment in the continuous silicon-carbon negative electrode production process according to claim 5, characterized in that: A third bearing (32) and a connecting plate (33) are arranged between the furnace tube (10) and the sleeve (21); a second cover plate (34) is arranged at the end of the sleeve (21); a driven gear (20) arranged on the outside of the sleeve (21) is meshed with a driving gear (16) arranged on the second rotating shaft (17) for transmission; and a driving pulley (19) arranged on the second rotating shaft (17) is transmission-connected to a driven pulley (23) on the first rotating shaft (11) via a belt (22).

7. The equipment in the continuous silicon-carbon negative electrode production process according to claim 6, characterized in that: One end of the second rotating shaft (17) is rotatably disposed in the second supporting seat (15), and the other end of the second rotating shaft (17) is connected to the output shaft end of the second motor (18).

8. The equipment in the continuous silicon-carbon negative electrode production process according to claim 7, characterized in that: The first material lifting plate (12) is a rectangular plate-shaped structure, the second material lifting plate (13) is an inclined plate-shaped structure, and the third material lifting plate (14) is an S-shaped curved plate-shaped structure.

9. The equipment in the continuous silicon-carbon negative electrode production process according to claim 8, characterized in that: A plurality of thermometers (27) are arranged on the housing (26), an air outlet pipe (31) is arranged on the side of the housing (26) and on the feeding tube (4), and a control valve (24) is arranged on the air inlet pipe (25).

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