Equipment for continuously preparing silicon-carbon negative electrode material

Abstract

The embodiment of the utility model discloses equipment for continuously preparing a silicon-carbon negative electrode material. The equipment comprises a silane vacuum adsorption unit, a first pipeline, a silane pyrolysis unit, a second pipeline, a silane pyrolysis cooling unit, a third pipeline and a carbon source coating device which are connected in sequence, the silane vacuum adsorption unit is used for adsorbing silane gas by the carbon carrier in a saturated manner; the silane pyrolysis unit is used for stirring a carbon material; the silane cracking and cooling unit is used for cooling the first intermediate product; and the carbon source coating device is used for carrying out carbon source gas coating on the silicon-carbon composite material. According to the embodiment of the utility model, the carbon carrier is subjected to saturated adsorption in the silane vacuum adsorption unit, so that a large amount of nitrogen is prevented from being introduced as carrier gas, pores of the carbon carrier are fully filled with silane gas, and a carbon material is put in the silane pyrolysis unit to perform a silane pyrolysis deposition reaction; the adsorption process and the pyrolytic deposition process are carried out in two reaction containers, so that the process stability is improved, and the process complexity is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of lithium ion battery negative material, especially in series preparation silicon carbon negative material's equipment. BACKGROUND

[0002] Lithium ion batteries have been widely used in recent years in portable electronic devices, large-scale energy storage devices, electric vehicles and other fields. Compared with the commonly used graphite negative electrode in lithium ion batteries, silicon material has ultra-high theoretical specific capacity and low delithiation potential, which makes silicon material one of the potential choices for upgrading and replacing carbon-based negative electrodes of lithium ion batteries. However, as a semiconductor material, the electrical conductivity of silicon is relatively low. During the electrochemical cycle process, the insertion and extraction of lithium ions will cause the material to expand and shrink by more than 300%, and the mechanical force generated will cause the material to gradually pulverize, resulting in structural collapse, ultimately leading to the separation of the electrode active material and the current collector, losing electrical contact, and greatly reducing the cycle performance of the battery. In addition, due to this volume effect, silicon is difficult to form a stable solid electrolyte interface (SEI) film in the electrolyte. With the destruction of the electrode structure, new SEI films are continuously formed on the exposed silicon surface, exacerbating the corrosion and capacity decay of silicon.

[0003] Currently, most of the silicon-carbon negative electrode materials are prepared using silane gas as the silicon source and porous carbon as the carrier. The porous carbon carrier is placed in a fluidized bed reaction unit, then nitrogen gas is introduced to remove oxygen, and then the temperature is raised to a specified temperature. An appropriate amount of silane gas is then introduced, and the porous carbon is fluidized using the introduced gas flow. In this process, the gas is simultaneously adsorbed. Due to the high activity of silane, nanosilicon generated by the dehydrogenation of silane cracking at this temperature is deposited in the porous carbon carrier.

[0004] However, in the existing scheme, adsorption and dehydrogenation cracking are carried out in the same reaction unit. As nanosilicon is deposited, the specific surface area of the reaction product gradually decreases, the weight of the reaction product continuously increases, and the powder state continuously changes, affecting the fluidization state. Therefore, it is necessary to adjust processes such as gas flow, ratio of reaction gas to carrier gas, etc. to ensure sufficient fluidization state, resulting in poor process stability. In addition, in the existing scheme, the gas is introduced from the bottom of the fluidized bed and diffuses out after passing through a porous carbon bed layer with a certain thickness. Therefore, the concentration of silane at the bottom or lower part of the bed is always higher than that at the upper part of the bed. The high concentration of silane in the middle and lower parts exceeds the adsorption capacity of the micropores or mesopores of the porous carbon, causing silane to inevitably deposit on the surface of the porous carbon. The surface "floating silicon" lacks the rigid restraint of the inner wall of the pores and is easily damaged in the later repeated charging and discharging processes, leading to the destruction of the surface carbon coating layer and the SEI film, and thus significantly reducing the cycle performance. SUMMARY

[0005] The utility model discloses a kind of equipment for continuously preparing silicon-carbon negative electrode material for at least part of problems and deficiencies in prior art.

[0006] In an aspect, the utility model discloses a kind of equipment for continuously preparing silicon-carbon negative electrode material, for example include: silane vacuum adsorption unit, for in vacuum environment and at first temperature with carbon carrier saturated adsorption silane gas to obtain the carbon material of saturated adsorption silane gas;Silane pyrolysis unit is connected the silane vacuum adsorption unit, the silane pyrolysis unit is used to stir after the carbon material of the saturated adsorption silane gas at second temperature to obtain the first intermediate product;Silane cracking cooling unit is connected the silane pyrolysis unit, the silane cracking cooling unit is used to cool the first intermediate product to third temperature to obtain the silicon-carbon composite material of silane cracking deposition nanometer silicon;Carbon source coating device is connected the silane cracking cooling unit, the carbon source coating device is used to form coating layer to obtain the silicon-carbon negative electrode material by carbon source gas coating in the silicon-carbon composite material of silane cracking deposition nanometer silicon surface;Pipeline assembly, including first pipeline, second pipeline and third pipeline, wherein the first pipeline is connected between the silane vacuum adsorption unit and the silane pyrolysis unit, the second pipeline is connected between the silane pyrolysis unit and the silane cracking cooling unit, the third pipeline is connected between the silane cracking cooling unit and the carbon source coating device.

[0007] The utility model embodiment carries out saturated adsorption to carbon carrier in the vacuum environment in silane vacuum adsorption unit, avoids that main stream craft needs to pass in a large number of nitrogen as carrier gas using fluidized bed, saves cost, and the most important thing is to realize that the pore of carbon carrier is filled with silane gas fully;Subsequently, the carbon material of saturated adsorption silane gas is placed in silane pyrolysis unit and carries out silane pyrolysis deposition reaction, is based on adsorption process and silane pyrolysis deposition process in two reaction containers, avoids the problem that the process stability is not good caused by adsorption treatment and pyrolysis deposition treatment in the same fluidized bed body in current general adoption, and then the complexity of existing process is reduced greatly.

[0008] In an embodiment of the utility model, the pipeline assembly further includes a fourth pipeline connected between the silane cracking cooling unit and the silane vacuum adsorption unit;The silane cracking cooling unit is further used to: when the silicon content in the silicon-carbon composite material of silane cracking deposition nanometer silicon reaches a first predetermined content, the silicon-carbon composite material of silane cracking deposition nanometer silicon is sent into the carbon source coating device;When the silicon content in the silicon-carbon composite material of silane cracking deposition nanometer silicon does not reach the first predetermined content, the silicon-carbon composite material of silane cracking deposition nanometer silicon is sent into the silane vacuum adsorption unit;Wherein, the first predetermined content is 45-60%.

[0009] In an embodiment of the utility model, the carbon source coating device specifically includes: organic carbon source pyrolysis coating unit, third pipeline is connected between silane cracking cooling unit with organic carbon source pyrolysis coating unit, organic carbon source pyrolysis coating unit is used to heat the silicon-carbon composite material of silane cracking deposition nanometer silicon under the protection of inert atmosphere at fourth temperature, and the carbon source gas is coated on the surface of the silicon-carbon composite material of silane cracking deposition nanometer silicon, obtains second intermediate product, cooling discharge unit is connected with organic carbon source pyrolysis coating unit, and the cooling discharge unit is used to cool the second intermediate product to fifth temperature and obtain the silicon-carbon negative electrode material, the pipeline assembly further includes fifth pipeline, and the fifth pipeline is connected between organic carbon source pyrolysis coating unit and cooling discharge unit.

[0010] In an embodiment of the utility model, the silane vacuum adsorption unit includes: a first body having a first accommodating cavity inside, a first silane input port and a first nitrogen gas input port are arranged on the first body; a first gas pressure detection structure is arranged on the first body and communicates with the first accommodating cavity, and the first gas pressure detection structure is used for measuring the gas pressure of the first accommodating cavity; a first oxygen content detection structure is arranged on the first body and communicates with the first accommodating cavity, and the first gas pressure detection structure is used for measuring the oxygen content of the first accommodating cavity.

[0011] In an embodiment of the utility model, the silane pyrolysis unit includes: a second body having a second accommodating cavity inside; a first heating structure is arranged on the first body, and the first heating structure is used for heating the reactant in the second accommodating cavity; a second oxygen content detection structure is arranged on the second body and communicates with the second accommodating cavity, and the second gas pressure detection structure is used for measuring the oxygen content of the second accommodating cavity.

[0012] In an embodiment of the utility model, the silane cracking cooling unit includes: a third body having a third accommodating cavity inside; a first cooling structure is arranged on the third body, and the first cooling structure is used for cooling the reactant in the third accommodating cavity; a third oxygen content detection structure is arranged on the third body and communicates with the third accommodating cavity, and the third gas pressure detection structure is used for measuring the oxygen content of the third accommodating cavity.

[0013] In an embodiment of the utility model, the carbon source pyrolysis coating unit includes: fourth main body, the fourth main body has fourth accommodation cavity inside, be provided with fourth nitrogen input and carbon source gas input on the fourth main body, second heating structure, set up on the fourth main body, second heating structure is used for heating the reactant in the fourth accommodation cavity, fourth oxygen content detection structure, set up on the fourth main body and communicate the fourth accommodation cavity, fourth gas pressure detection structure is used for measuring the oxygen content of fourth accommodation cavity.

[0014] In an embodiment of the utility model, the silane vacuum adsorption unit is provided with a first valve connected with the first pipeline and used for controlling opening and closing of the first pipeline, the silane pyrolysis unit includes a second valve connected with the second pipeline and used for controlling opening and closing of the second pipeline, the silane cracking and cooling unit includes a third valve connected with the third pipeline and used for controlling opening and closing of the third pipeline and a fourth valve connected with the fourth pipeline and used for controlling opening and closing of the fourth pipeline, and the organic carbon source pyrolysis coating unit includes a fifth valve connected with the fifth pipeline and used for controlling opening and closing of the fifth pipeline.

[0015] In an embodiment of the utility model, the tail gas conveying unit is used for processing tail gas in the silane pyrolysis unit, the silane cracking and cooling unit, the silane vacuum adsorption unit and the carbon source coating device, and / or the air extraction unit is used for vacuumizing the deposition device, the silane vacuum adsorption unit and the carbon source coating device.

[0016] In an embodiment of the utility model, the material conveying unit is connected with the silane vacuum adsorption unit and used for conveying the carbon carrier to the silane vacuum adsorption unit.

[0017] From the above, the technical features of the present application can have one or more of the following beneficial effects: the embodiment of the present application carries out saturated adsorption on the carbon carrier in the silane vacuum adsorption unit under vacuum environment, avoids the need for a large amount of nitrogen as a carrier gas in the mainstream process using a fluidized bed, saves costs, and importantly realizes the full filling of silane gas in the pores of the carbon carrier; then the carbon material saturated with silane gas is placed in the silane pyrolysis unit for silane pyrolysis deposition reaction, and the adsorption process and the silane pyrolysis deposition process are carried out in two reaction containers, which avoids the problem of poor process stability caused by the adsorption treatment and the pyrolysis deposition treatment in the same fluidized bed body, and further greatly reduces the complexity of the existing process; the effective control of the amount of silane adsorption and deposition is realized through the circulation mode, the problem of "silicon floating" on the surface of the carbon carrier is avoided, and the stability of the process is significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creating laborious work.

[0019] Figure 1 The structure schematic diagram of the equipment for continuously preparing silicon-carbon negative electrode material provided by the embodiment of the present application.

[0020] Figure 2 Another structure schematic diagram of the equipment for continuously preparing silicon-carbon negative electrode material provided by the embodiment of the present application.

[0021] Explanation of reference signs:

[0022] 10-equipment for continuously preparing silicon-carbon negative electrode material; 100-inlet conveying unit; 110-carrier gas channel;

[0023] 200-silane vacuum adsorption unit; 201-first main body; 2011-first silane input port; 2012-first nitrogen input port; 203-first air pressure detection structure; 204-first oxygen content detection structure; 205-first valve;

[0024] 310-silane pyrolysis unit; 311-second main body; 312-first heating structure; 314-second oxygen content detection structure; 315-second valve; 320-silane cracking cooling unit; 321-third main body; 322-first cooling structure; 324-third oxygen content detection structure; 325-third valve; 326-fourth valve;

[0025] 400-carbon source coating device; 410-organic carbon source pyrolysis coating unit; 411-fourth main body; 4111-fourth nitrogen gas input port; 4112-carbon source gas input port; 412-second heating structure; 414-fourth oxygen content detection structure; 415-fifth valve; 420-cooling and discharging unit;

[0026] 500-pipe assembly; 510-first pipe; 520-second pipe; 530-third pipe; 540-fourth pipe; 550-fifth pipe;

[0027] 600-tail gas conveying unit; 700-gas extraction unit. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below in combination with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the terms thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0030] It should also be noted that the division of the multiple embodiments in the present application is only for the convenience of description, and should not constitute a special limitation. The features in various embodiments can be combined and mutually referenced without contradiction.

[0031] Reference should be made to Figure 1The utility model discloses a kind of equipment 10 for continuously preparing silicon-carbon negative electrode material, for example including silane vacuum adsorption unit 200, silane pyrolysis unit 310, silane cracking cooling unit 320, carbon source coating device 400 and pipeline assembly 500.Wherein, silane vacuum adsorption unit 200 is for example set to the first side of silane pyrolysis unit 310, and is connected with silane pyrolysis unit 310, silane cracking cooling unit 320 is for example set to the second side of silane pyrolysis unit 310, and is connected with silane pyrolysis unit 310, carbon source coating device 400 is for example connected with silane cracking cooling unit 320.Silane vacuum adsorption unit 200 is for example used to saturate adsorption silane gas carbon carrier in vacuum environment and at first temperature to obtain the carbon material of saturated adsorption silane gas, silane pyrolysis unit 310 is for example used to stir the carbon material of the saturated adsorption silane gas at second temperature to obtain the first intermediate product, silane cracking cooling unit 320 is for example used to cool the first intermediate product to third temperature to obtain the silicon-carbon composite material of silane cracking deposition nanometer silicon, carbon source coating device 400 is for example used to form coating layer by carbon source gas coating on the surface of the silicon-carbon composite material of silane cracking deposition nanometer silicon to obtain the silicon-carbon negative electrode material.Pipeline assembly 500 is for example including first pipeline 510, second pipeline 520 and third pipeline 530, wherein the first pipeline 510 is connected between the silane vacuum adsorption unit 200 and the silane pyrolysis unit 310, the second pipeline 520 is connected between the silane pyrolysis unit 310 and the silane cracking cooling unit 320, and the third pipeline 530 is connected between the silane cracking cooling unit 320 and the carbon source coating device 400.Wherein, the first temperature is 25-360 ℃, the second temperature is 480-600 ℃, and the third temperature is less than or equal to 360 ℃.

[0032] For example, the user can place the carbon carrier in the silane vacuum adsorption unit 200 to saturate adsorption silane gas to obtain the carbon material of saturated adsorption silane gas, and then the carbon material of saturated adsorption silane gas enters the silane pyrolysis unit 310 for high-temperature stirring, and then enters the silane cracking cooling unit 320 for cooling. The dehydrogenation cracking reaction of silane in the carbon material of saturated adsorption silane gas at high temperature, and the nanometer silicon is deposited in the pore of the carbon carrier to obtain the silicon-carbon composite material of silane cracking deposition nanometer silicon. Then, the silicon-carbon composite material of silane cracking deposition nanometer silicon enters the carbon source coating device 400 for carbon source gas coating to obtain the silicon-carbon negative electrode material.

[0033] For example, the above-mentioned carbon carrier is, for example, a porous carbon material, and the above-mentioned silane gas is, for example, a silane gas.

[0034] The embodiment of the utility model carries out saturated adsorption to carbon carrier under vacuum environment in silane vacuum adsorption unit, avoided the main stream craft to adopt fluidized bed to need to pass in a large number of nitrogen as carrier gas, saved the cost, the important thing is realized the full filling of silane gas to carbon carrier's pore, then place carbon material of saturated adsorption silane gas in silane pyrolysis unit and carry out silane pyrolysis deposition reaction, based on adsorption process and silane pyrolysis deposition process in two reaction containers, avoided the problem of poor process stability caused by adsorption treatment and pyrolysis deposition treatment in the same fluidized bed body in the current general adoption, and further greatly reduced the complexity of the existing process.

[0035] In the foregoing, in one specific embodiment, the pipeline assembly 500 further comprises a fourth pipeline 540 connected between the silane cracking cooling unit 320 and the silane vacuum adsorption unit 200, i.e., the silane cracking cooling unit 320 is also connected to the silane vacuum adsorption unit 200. The silane cracking cooling unit 320 is further configured to: when the silicon content in the silane pyrolysis deposition nanosilicon silicon-carbon composite material reaches a first predetermined content, send the silane pyrolysis deposition nanosilicon silicon-carbon composite material into the carbon source coating device 400; and when the silicon content in the silane pyrolysis deposition nanosilicon silicon-carbon composite material does not reach the first predetermined content, send the silane pyrolysis deposition nanosilicon silicon-carbon composite material into the silane vacuum adsorption unit 200. The first predetermined content is 45-60%. For example, the user detects the silicon content in the silane pyrolysis deposition nanosilicon silicon-carbon composite material in the silane cracking cooling unit 320, and when the silicon content reaches 45-60%, the silane pyrolysis deposition nanosilicon silicon-carbon composite material can enter the carbon source coating device 400 for subsequent carbon source coating treatment, and when the silicon content does not reach 45-60%, the silane pyrolysis deposition nanosilicon silicon-carbon composite material needs to enter the silane vacuum adsorption unit 200 for repeated silane saturated adsorption and pyrolysis deposition treatment until the silicon content in the silane pyrolysis deposition nanosilicon silicon-carbon composite material reaches 45-60%.

[0036] Further, referring again to Figure 1The carbon source coating device 400 specifically comprises an organic carbon source pyrolysis coating unit 410 and a cooling discharge unit 420. The silane cracking cooling unit 320 is arranged on a first side of the organic carbon source pyrolysis coating unit 410 and connected to the organic carbon source pyrolysis coating unit 410, and the cooling discharge unit 420 is arranged on a second side of the organic carbon source pyrolysis coating unit 410 and connected to the organic carbon source pyrolysis coating unit 410. The pipe assembly 500 further comprises a fifth pipe 550 connected between the organic carbon source pyrolysis coating unit 410 and the cooling discharge unit 420. By arranging the silane vacuum adsorption unit 200 and the silane cracking cooling unit 320 on different sides of the silane pyrolysis unit 310, and arranging the silane cracking cooling unit 320 and the cooling discharge unit 420 on different sides of the organic carbon source pyrolysis coating unit 410, the silane vacuum adsorption unit 200, the silane pyrolysis unit 310, the silane cracking cooling unit 320, the organic carbon source pyrolysis coating unit 410 and the cooling discharge unit 420 can form a complete production line, and the reactants can reasonably travel on the production line.

[0037] As described above, the organic carbon source pyrolysis coating unit 410 is used to heat the silane cracking deposited nanosilicon silicon-carbon composite material at a fourth temperature under the protection of the inert atmosphere, and coat the carbon source gas on the surface of the silane cracking deposited nanosilicon silicon-carbon composite material, to obtain a second intermediate product. The cooling discharge unit 420 is used to cool the second intermediate product to a fifth temperature to obtain the silicon-carbon negative electrode material. The fourth temperature is 500-750°C, and the fifth temperature is less than or equal to 50°C.

[0038] Referring again to Figure 1 The silane vacuum adsorption unit 200 is provided with a first valve 205 connected to the first pipe 510 and used to control the opening and closing of the first pipe 510. The silane pyrolysis unit 310 comprises a second valve 315 connected to the second pipe 520 and used to control the opening and closing of the second pipe 520. The silane cracking cooling unit 320 comprises a third valve 325 connected to the third pipe 530 and used to control the opening and closing of the third pipe 530, and a fourth valve 326 connected to the fourth pipe 540 and used to control the opening and closing of the fourth pipe 540. The carbon source pyrolysis coating unit 410 comprises a fifth valve 415 connected to the fifth pipe 550 and used to control the opening and closing of the fifth pipe 550.

[0039] Further referring to Figure 1The apparatus 10 for continuously preparing the silicon-carbon negative electrode material further comprises, for example, a tail gas conveying unit 600 and / or a vacuum pumping unit 700. The deposition device 300, the silane vacuum adsorption unit 200 and the carbon source coating device 500 are connected to the tail gas conveying unit 600, respectively, which is used to treat the tail gas in the silane pyrolysis unit 310, the silane cracking cooling unit 320, the silane vacuum adsorption unit 200 and the carbon source coating device 400. The deposition device 300, the silane vacuum adsorption unit 200 and the carbon source coating device 500 are further connected to the vacuum pumping unit 700, respectively, which is used to vacuumize the deposition device 300, the silane vacuum adsorption unit 200 and the carbon source coating device 400. For example, the vacuum pumping unit 700 is a vacuum pump.

[0040] Further, referring to Figure 1 The apparatus 10 for continuously preparing the silicon-carbon negative electrode material further comprises, for example, a material conveying unit 100. The material conveying unit 100 is connected to the silane vacuum adsorption unit 200, which is used to convey the carbon carrier to the silane vacuum adsorption unit 200. For example, the material conveying unit 100 is connected to the fourth pipeline 540, through which the carbon carrier is conveyed to the silane vacuum adsorption unit 200. Of course, the specific position of the material conveying unit 100 can be changed according to the actual situation, which is not limited in the present application. The material conveying unit 100 further comprises a carrier passage 110, which is used to pass the carrier gas.

[0041] In a specific embodiment, referring to Figure 2 The silane vacuum adsorption unit 200 comprises, for example, a first body 201, a first gas pressure detection structure 203 and a first oxygen content detection structure 204. The first body 201 has, for example, a first accommodating cavity in which the reactants react. The first body 201 is further provided with a first silane input port 2011 and a first nitrogen gas input port 2012. The first gas pressure detection structure 203 is arranged on the first body 201 and communicates with the first accommodating cavity. The first gas pressure detection structure 203 is used to measure the gas pressure in the first accommodating cavity. For example, the first gas pressure detection structure 203 is a gas pressure detector. The first oxygen content detection structure 204 is arranged on the first body 201 and communicates with the first accommodating cavity. The first oxygen content detection structure 204 is used to measure the oxygen content in the first accommodating cavity. For example, the first oxygen content detection structure 204 is an oxygen content detector.

[0042] As described above, referring to Figure 2, the silane pyrolysis unit 310 for example comprises a second main body 311, a first heating structure 312 and a second oxygen content detection structure 314. The second main body 311 for example has a second accommodating cavity therein, and reactants for example react in the second accommodating cavity. The first heating structure 312 is disposed on the second main body 311, and is used to heat the reactants in the second accommodating cavity. The first heating structure 312 for example is a sleeve structure disposed on the second main body 311, and is for example a heater, but can also be other structures capable of heating, which are not limited in the present application. The second oxygen content detection structure 314 is disposed on the second main body 311 and is in communication with the second accommodating cavity, and is used to measure the oxygen content of the second accommodating cavity. The second oxygen content detection structure 314 for example is an oxygen content detector.

[0043] Referring to Figure 2 , the silane pyrolysis unit 310 for example comprises a second main body 311, a first heating structure 312 and a second oxygen content detection structure 314. The second main body 311 for example has a second accommodating cavity therein, and reactants for example react in the second accommodating cavity. The first heating structure 312 is disposed on the second main body 311, and is used to heat the reactants in the second accommodating cavity. The first heating structure 312 for example is a sleeve structure disposed on the second main body 311, and is for example a heater, but can also be other structures capable of heating, which are not limited in the present application. The second oxygen content detection structure 314 is disposed on the second main body 311 and is in communication with the second accommodating cavity, and is used to measure the oxygen content of the second accommodating cavity. The second oxygen content detection structure 314 for example is an oxygen content detector.

[0044] In addition, referring again to Figure 2The carbon source pyrolysis coating unit 410, for example, comprises a fourth body 411, a second heating structure 412, and a fourth oxygen content detection structure 414. The fourth body 411 has a fourth accommodating cavity therein, and reactants react in the fourth accommodating cavity. The fourth body 411 is provided with a fourth nitrogen inlet 4111 and a carbon source gas inlet 4112. The second heating structure 412 is arranged on the fourth body 411 and is used to heat the reactants in the fourth accommodating cavity. For example, the second heating structure 412 is a heater, and can also be other structures that can heat, which is not limited in the present application. The fourth oxygen content detection structure 414 is arranged on the fourth body 411 and communicates with the fourth accommodating cavity. The fourth oxygen content detection structure 414 is used to measure the oxygen content of the fourth accommodating cavity. For example, the fourth oxygen content detection structure 414 is an oxygen content detector.

[0045] For example, the following briefly describes a production process of preparing the silicon-carbon negative electrode material using the device 10 for continuously preparing the silicon-carbon negative electrode material.

[0046] S1) After adding the carbon carrier in the feed conveying unit 100, the carrier gas channel 110 is opened, so that the carbon carrier is conveyed into the first accommodating cavity of the silane vacuum adsorption unit 200 by taking nitrogen as the carrier gas. After opening the exhaust unit 700 to vacuumize the first accommodating cavity to a first vacuum degree, the first nitrogen inlet 2012 is opened to introduce nitrogen to a first gas pressure. Whether the oxygen content in the first accommodating cavity reaches a predetermined oxygen content is detected by the first oxygen content detection structure 204. If not, the above operation is repeated until the predetermined oxygen content is reached. If so, the exhaust unit 700 is used to vacuumize to a second vacuum degree, and then the first silane inlet 2011 is opened to introduce silane gas to a first gas pressure. The first vacuum degree is 100 Pa, the second vacuum degree is 10 Pa, the first gas pressure is 105 Pa, and the predetermined oxygen content is 20 ppm.

[0047] S2) While S1) is performed, the silane pyrolysis unit 310 is subjected to oxygen removal treatment and the oxygen content is controlled to be lower than 20 ppm, and is heated to a corresponding reaction temperature of 480-600°C. Then, the first valve 205 of the silane vacuum adsorption unit 200 is opened, and the carbon material saturated with adsorbed silane gas enters the second accommodating cavity of the silane pyrolysis unit 310 through the first pipeline 510 by gravity. The carbon material saturated with adsorbed silane gas is uniformly heated under the heating of the first heating structure 312, so that the silane pyrolysis forms ultrafine nanosilicon deposited in the pores of the porous carbon, and a first intermediate product is obtained. A small amount of overflowed silane and dust mixed in the nitrogen protective gas are treated by the exhaust treatment unit 600.

[0048] S3) While performing S1), the silane cracking cold zone unit 320 is subjected to oxygen removal treatment and the oxygen content is controlled to be lower than 20 ppm. Then the second valve 315 of the silane pyrolysis unit 310 is opened, and the first intermediate product enters the third accommodating cavity of the silane cracking cold zone unit 320 through the second pipeline 520 by gravity. When the temperature of the silane cracking cold zone unit 320 is lower than 360℃, the first intermediate product is cooled in the silane cracking cold zone unit 320 to obtain a silicon-carbon composite material with deposited nanosilicon by cracking. If the silicon content in the silicon-carbon composite material with deposited nanosilicon by cracking does not reach 45-60%, the third valve 325 of the silane cracking cold zone unit 320 is opened, so that the silicon-carbon composite material with deposited nanosilicon by cracking enters the silane vacuum adsorption unit 200 through the third pipeline 530 to repeat the above steps, until the silicon content in the silicon-carbon composite material with deposited nanosilicon by cracking in the silane cracking cold zone unit 320 reaches 45-60%. The dust mixed in the nitrogen protective gas is treated by the tail gas treatment unit 600.

[0049] S4) While performing S1), the carbon source pyrolysis coating unit 410 is subjected to oxygen removal treatment and the oxygen content is controlled to be lower than 20 ppm, and is heated to the corresponding reaction temperature of 500-750℃. Then the fourth valve 326 of the silane cracking cold zone unit 320 and the fourth nitrogen inlet 4111 of the carbon source pyrolysis coating unit 410 are opened, and the silicon-carbon composite material with deposited nanosilicon by cracking enters the fourth accommodating cavity of the carbon source pyrolysis coating unit 410 through the fourth pipeline 540 under the protection of nitrogen by gravity. The carbon source gas inlet 4112 is opened, and one or more of acetylene, propylene and methane is used as the carbon source gas. The carbon source gas is cracked into carbon atoms and hydrogen atoms by heating, the carbon atoms are deposited and coated on the outer surface of the silicon-carbon composite material with deposited nanosilicon by cracking to complete the coating treatment to obtain a second intermediate product. The uncracked acetylene and the dust mixed in the nitrogen protective gas are treated by the tail gas treatment unit 600.

[0050] S5) While performing S4), the cooling discharge unit 420 is subjected to oxygen removal treatment and the oxygen content is controlled to be lower than 20 ppm. Then the fifth valve 415 of the carbon source pyrolysis coating unit 410 is opened, and the second intermediate product enters the cooling discharge unit 420 through the fifth pipeline 550 by gravity, and the second intermediate product is cooled to below 50℃ to obtain a silicon-carbon negative electrode material.

[0051] The embodiment of the utility model carries out saturated adsorption to carbon carrier under vacuum environment in silane vacuum adsorption unit, avoided the main stream craft to adopt fluidized bed to need to pass in a large number of nitrogen as carrier gas, saved the cost, the important thing is realized the full filling of silane gas to the pore of carbon carrier, then place carbon material of saturated adsorption silane gas in silane pyrolysis unit and carry out silane pyrolysis deposition reaction, based on adsorption process and silane pyrolysis deposition process in two reaction vessels, avoided the problem of poor process stability caused by adsorption treatment and pyrolysis deposition treatment in the same fluidized bed body in the current general adoption, and further greatly reduced the complexity of the existing process; through the circulation mode, the effective control of silane adsorption amount and deposition amount is realized, the problem of " floating silicon" on the surface of carbon carrier is avoided, and the stability of the process is significantly improved.

[0052] It can be understood that the foregoing various embodiments are only exemplary descriptions of the utility model, and the technical solutions of various embodiments can be used in any combination or collocation under the premise that the technical features do not conflict, the structures are not contradictory, and the invention purpose of the utility model is not violated.

[0053] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the utility model, and not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. An apparatus for continuously producing a silicon-carbon negative electrode material, characterized by, include: a silane vacuum adsorption unit, configured to saturate the carbon support with silane gas under a vacuum environment and at a first temperature to obtain a carbon material saturated with silane gas; a silane pyrolysis unit connected to the silane vacuum adsorption unit, the silane pyrolysis unit being configured to stir the carbon material saturated with silane gas at a second temperature to obtain a first intermediate product; a silane cracking cooling unit connected to the silane pyrolysis unit, the silane cracking cooling unit being used to cool the first intermediate product to a third temperature to obtain a silicon-carbon composite material with nano-silicon deposited by silane cracking; A carbon source coating device, connected to the silane cracking cooling unit, for coating the carbon source gas on the surface of the silicon-carbon composite material deposited by silane cracking nano-silicon to form a coating layer to obtain the silicon-carbon negative electrode material; The pipeline assembly includes a first pipeline, a second pipeline and a third pipeline, wherein the first pipeline is connected between the silane vacuum adsorption unit and the silane pyrolysis unit, the second pipeline is connected between the silane pyrolysis unit and the silane cracking cooling unit, and the third pipeline is connected between the silane cracking cooling unit and the carbon source coating device.

2. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 1, wherein The pipeline assembly further includes a fourth pipeline, wherein the fourth pipeline is connected between the silane cracking and cooling unit and the silane vacuum adsorption unit; The silane cracking cooling unit is also used to: when the silicon content in the silicon-carbon composite material of nano-silicon deposited by silane cracking reaches a first predetermined content, send the silicon-carbon composite material of nano-silicon deposited by silane cracking into the carbon source coating device; when the silicon content in the silicon-carbon composite material of nano-silicon deposited by silane cracking does not reach the first predetermined content, send the silicon-carbon composite material of nano-silicon deposited by silane cracking into the silane vacuum adsorption unit; wherein the first predetermined content is 45-60%.

3. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 2, wherein The carbon source coating device specifically includes: An organic carbon source pyrolysis and coating unit, wherein the third pipeline is connected between the silane cracking and cooling unit and the organic carbon source pyrolysis and coating unit, and the organic carbon source pyrolysis and coating unit is used to heat the silicon-carbon composite material obtained by silane cracking and depositing nano-silicon at a fourth temperature under the protection of an inert atmosphere, and coat the carbon source gas on the surface of the silicon-carbon composite material obtained by silane cracking and depositing nano-silicon, to obtain a second intermediate product; a cooling and discharging unit connected to the organic carbon source pyrolysis and coating unit, and configured to cool the second intermediate product to a fifth temperature to obtain the silicon-carbon negative electrode material; The pipeline assembly further includes a fifth pipeline connected between the organic carbon source pyrolysis and coating unit and the cooling and discharging unit.

4. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 3, wherein The silane vacuum adsorption unit comprises: A first main body, wherein the first main body has a first accommodating cavity therein and is provided with a first silane input port and a first nitrogen input port; a first air pressure detection structure, disposed on the first main body and connected to the first accommodating cavity, the first air pressure detection structure being used to measure the air pressure of the first accommodating cavity; A first oxygen content detection structure is disposed on the first main body and is in communication with the first accommodating cavity. The first oxygen content detection structure is used to measure the oxygen content of the first accommodating cavity.

5. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 3, wherein The silane pyrolysis unit comprises: A second main body has a second accommodating cavity therein; A first heating structure is disposed on the second main body. The first heating structure is used to heat the reactants in the second accommodating cavity; A second oxygen content detection structure is disposed on the second main body and is in communication with the second accommodating cavity. The second oxygen content detection structure is used to measure the oxygen content of the second accommodating cavity.

6. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 3, wherein The silane pyrolysis unit comprises: A third main body has a third accommodating cavity therein; A first cooling structure is disposed on the third main body. The first cooling structure is used to cool the reactants in the third accommodating cavity; A third oxygen content detection structure is disposed on the third main body and is in communication with the third accommodating cavity. The third oxygen content detection structure is used to measure the oxygen content of the third accommodating cavity.

7. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 3, wherein The carbon source pyrolysis coating unit comprises: A fourth main body has a fourth accommodating cavity therein. The fourth main body is provided with a fourth nitrogen gas input port and a carbon source gas input port; A second heating structure is disposed on the fourth main body. The second heating structure is used to heat the reactants in the fourth accommodating cavity; A fourth oxygen content detection structure is disposed on the fourth main body and is in communication with the fourth accommodating cavity. The fourth oxygen content detection structure is used to measure the oxygen content of the fourth accommodating cavity.

8. The apparatus for continuously producing a silicon-carbon negative electrode material according to any one of claims 3 to 7, characterized by, The silane vacuum adsorption unit is provided with a first valve connected to the first pipeline and used to control the opening and closing of the first pipeline; The silane pyrolysis unit comprises a second valve connected to the second pipeline and used to control the opening and closing of the second pipeline; The silane pyrolysis unit comprises a second valve connected to the second pipeline and used to control the opening and closing of the second pipeline; The organic carbon source pyrolysis coating unit comprises a fifth valve connected to the fifth pipeline and used to control the opening and closing of the fifth pipeline.

9. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 8, wherein Further comprising: A tail gas conveying unit connected to the silane pyrolysis unit, the silane cracking and cooling unit, the silane vacuum adsorption unit, and the carbon source coating device. The tail gas conveying unit is used to process the tail gas in the silane pyrolysis unit, the silane cracking and cooling unit, the silane vacuum adsorption unit, and the carbon source coating device; and / or A gas extraction unit connected to the silane pyrolysis unit, the silane cracking and cooling unit, the silane vacuum adsorption unit, and the carbon source coating device. The gas extraction unit is used to extract vacuum in the silane pyrolysis unit, the silane cracking and cooling unit, the silane vacuum adsorption unit, and the carbon source coating device.

10. The apparatus for continuously producing a silicon-carbon negative electrode material according to claim 8, wherein Further comprising: A feed conveying unit is connected to the silane vacuum adsorption unit, and is used to convey the carbon carrier to the silane vacuum adsorption unit.

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