Production equipment and method of controllable high-performance novel silicon-carbon negative electrode material

Abstract

The invention provides production equipment and method of a controllable high-performance novel silicon-carbon negative electrode material. The production equipment of the controllable high-performance novel silicon-carbon negative electrode material comprises a cracking cabin, an atmosphere cabin, an online monitoring system, a pressure control system and a gas source management system, the cracking cabin is positioned in the atmosphere cabin and can horizontally rotate; the pressure control system and the gas source management system are connected with the cracking cabin; the pressure control system is configured to adjust the pressure of the cracking cabin, the gas source management system is configured to input inert gas, or silane gas and inert gas, or carbon source gas and inert gas into the cracking cabin, the pressure value of the cracking cabin changes in a certain gradient, and the online monitoring system is configured to monitor the reaction safety threshold value of production equipment and control the siliconizing amount. The production method of the controllable high-performance novel silicon-carbon negative electrode material is realized through the production equipment of the controllable high-performance novel silicon-carbon negative electrode material. The cracking gradient layer number can be controlled, the siliconizing ratio is flexibly adjusted, and the sudden explosion probability is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery negative electrode material preparation, and in particular to a production device and method for a controllable high-performance novel silicon-carbon negative electrode material. Background Art

[0002] The energy crisis is a serious challenge facing the world today. The development and life of human society cannot be separated from the support of energy. China's main fossil energy still relies on imports. As fossil energy is non-renewable and the global situation is becoming increasingly severe, the development of the new energy industry is necessary and inevitable. Traditional renewable energy is difficult to integrate into the power grid due to its regionality and time limit. It is necessary to further improve battery energy storage and battery capacity. It is difficult for existing graphite negative electrodes to do this. This makes the energy field's need to find an alternative negative electrode material with a higher specific capacity even more obvious. The most impressive is the silicon-based material, with its high theoretical specific capacity (4200mAh g -1 ), suitable working potential (~0.4V vs.Li / Li + ) and abundant natural reserves make it one of the most attractive alternative negative electrodes. However, the practical application of silicon negative electrodes is limited by its huge volume expansion rate (~400%) and the repeated accumulation of SEI film, which leads to mechanical crushing, structural degradation and extremely fast capacity decay. Therefore, silicon-based negative electrode materials have developed two new routes: silicon-carbon negative electrode and silicon-oxygen negative electrode.

[0003] Since the surface of the silicon-oxygen negative electrode is coated with silicon oxide, lithium oxide and lithium silicate will be continuously generated during the cycle, resulting in poor conductivity and poor cycle rate. In order to solve the first-effect problem of silicon-oxygen materials, material factories introduced active lithium salts to pre-lithiate silicon-oxygen materials, which caused the alkalinity of the materials to be too high, corroding equipment and making them difficult to apply to pulping and coating in battery cell factories.

[0004] The new silicon-carbon negative electrode is made by uniformly depositing silicon in porous carbon, and then performing secondary carbon coating. Through the skeleton structure of the porous carbon itself, it achieves high performance and inhibits the crushing of silicon particles. The commercial battery cells of the new silicon-carbon material are generally required to have more than 2,000 cycles. Its capacity, first efficiency and cycle performance are far superior to other conventional negative electrode materials, including silicon-oxygen negative electrode materials.

[0005] The existing technology generally adopts the fluidized bed method and the rotary furnace method, and both methods currently have many problems. The fluidized bed method first uses gas to boil the powder, and the gas consumption in this process is very large; secondly, due to the presence of nano-silicon on the surface of the siliconized precursor, direct removal will cause spontaneous combustion, which is very dangerous. Therefore, the precursor has to be carbon-coated twice in the fluidized bed to solve this hidden danger, but acetylene and other carbon source gases will undergo violent condensation reactions in the fluidized bed. When the furnace body is in an environment of a large amount of hydrogen, flammable dust, silane, and hydrocarbon gases, explosions may occur at any time regardless of the heating, constant temperature, or cooling process, and there have been many domestic explosion cases; at the same time, the fluidized bed has strict requirements on the consistency of the carbon substrate, occupies a huge space, has a large area of ​​fluidization dead corners, the cold mold is very different from the furnace body, and can only use heavy resin carbon substrates. The surface area of ​​the material is seriously siliconized and the batch stability is poor. These problems have not yet been solved.

[0006] The rotary kiln method is to replace the traditional CVD equipment with silane cracking equipment, and synthesize the new silicon-carbon negative electrode by cracking the mixed gas of inert gas and silane. Due to atmosphere sintering, in actual production, it is difficult for silane to enter the mesopores and micropores of the porous carbon-carbon substrate, and it grows more on the surface of the carbon substrate, which makes the synthesis of the new silicon-carbon negative electrode become the synthesis of micron silicon-coated carbon. Since silicon does not enter the porous carbon skeleton, its cycle performance is extremely poor; at the same time, the rotary kiln method is difficult to control the amount of silicon penetration, and it is prone to leakage and explosion.

[0007] In view of the above-mentioned technical difficulties, the traditional fluidized bed method and rotary kiln method are difficult to be applied to the production and preparation of new silicon-carbon negative electrodes; at the same time, the super-active nature of silane gas is very easy to explode in actual pilot and mass production, causing casualties and property losses, which brings huge challenges to large-scale production. Therefore, it is of great significance to provide a production device and method for a controllable high-performance new silicon-carbon negative electrode material. Summary of the invention

[0008] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to solve the technical problem that the traditional production and preparation method of the new silicon-carbon negative electrode is prone to explosion, and the second purpose is to solve the technical problem that it is difficult to control the amount of siliconization.

[0009] In order to achieve the above-mentioned objectives, on the one hand, the present invention provides a production equipment for a controllable high-performance new silicon-carbon negative electrode material, wherein the production equipment may include a cracking chamber, an atmosphere chamber, an online monitoring system, a pressure control system and a gas source management system, wherein the cracking chamber is located in the atmosphere chamber, and the cracking chamber can rotate horizontally; the pressure control system and the gas source management system are both connected to the cracking chamber; the pressure control system is configured to perform pressure adjustment processing on the cracking chamber, and the gas source management system is configured to input inert gas, or silane gas and inert gas, or carbon source gas and inert gas into the cracking chamber, and the pressure value of the cracking chamber changes with a certain gradient, and the online monitoring system is configured to monitor the reaction safety threshold of the production equipment and control the amount of silicon penetration.

[0010] According to an exemplary embodiment of one aspect of the present invention, a nested shaft may be provided at one end of the cracking chamber, the nested shaft passes through the atmosphere chamber and is connected to the motor, the pressure control system and the gas source management system may be connected to the nested shaft, and a sampler of a gas pressure and concentration sensor may be provided in the nested shaft and connected to the online monitoring system.

[0011] According to an exemplary embodiment of one aspect of the present invention, the body of the atmosphere chamber may include a metal layer, a thermal insulation layer and a nested heating assembly from the outside to the inside; a gas pressure and concentration sensor may be installed on the top of the atmosphere chamber, and the gas pressure and concentration sensor may be connected to an online monitoring system.

[0012] According to an exemplary embodiment of one aspect of the present invention, a plurality of limiting wheels may be provided at the bottom of the lysis chamber to provide the support and limiting required for the rotation of the lysis chamber.

[0013] According to an exemplary embodiment of an aspect of the present invention, a lifting device may be provided at the bottom of the atmosphere chamber.

[0014] According to an exemplary embodiment of one aspect of the present invention, an outer cabin door may be provided at one end of the atmosphere cabin, and an inner cabin door may be provided at one end of the cracking cabin, and the outer cabin door and the inner cabin door are in the same direction.

[0015] According to an exemplary embodiment of an aspect of the present invention, the inner door may be sequentially connected to a ball valve and an incinerator via a pipeline.

[0016] Another aspect of the present invention provides a method for producing a controllable high-performance new silicon-carbon negative electrode material. The production method can be implemented by the production equipment for the controllable high-performance new silicon-carbon negative electrode material as described above. The production method can include the following steps: S1, loading the carbon substrate into a cracking chamber, and adjusting the pressure of the cracking chamber to 1-100 Pa; the amount of the carbon substrate added is 10-95% of the volume of the cracking chamber; S2, rotating the cracking chamber, and the temperature is 500-650° C. and keeping it warm, The pressure is adjusted again to control the pressure value to 1-50Pa; S3, inert gas and silane gas are introduced into the cracking chamber to control the pressure change gradient of the cracking chamber, and the duration is 2-20 hours to obtain silicon-carbon precursors with different siliconization amounts; the mass of silane is 30-100% of the carbon substrate; S4, after introducing inert gas to make the cracking chamber slightly positive pressure, the temperature of the cracking chamber is adjusted to 500-700°C and kept warm, and carbon source gas and inert gas are introduced for secondary coating, and the coating time is 1-5 hours to obtain a new silicon-carbon negative electrode material.

[0017] According to an exemplary embodiment of another aspect of the present invention, the pressure change gradient may include 100Pa, 200Pa and 300Pa.

[0018] According to an exemplary embodiment of another aspect of the present invention, the carbon substrate may include one or more of resin carbon, biomass carbon, asphalt carbon and coke; the inert gas may include one or more of nitrogen, argon, helium and carbon dioxide; the silane concentration of the mixed gas of the inert gas and silane gas may be 2 to 100%; the carbon source gas may include one or more of methane, ethane, propane, ethylene, propylene and acetylene; the carbon source concentration of the mixed gas of the inert gas and carbon source gas may be 20 to 66%.

[0019] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0020] (1) The production equipment of the controllable high-performance new silicon-carbon negative electrode material proposed in the present invention can control the number of cracking gradient layers through the intelligent pressure control of the online monitoring system, and can flexibly adjust the siliconization ratio.

[0021] (2) The production method of the controllable high-performance new silicon-carbon negative electrode material proposed in the present invention reduces the risk of carbon source gas condensation explosion and improves the density of the carbon layer through low-medium temperature mixed hydrocarbon coating, thereby obtaining a high-performance new silicon-carbon negative electrode material.

[0022] (3) The production equipment of the controllable high-performance new silicon-carbon negative electrode material proposed in the present invention can solve the inherent safety, consistency, cost and other pain points of the existing fluidized bed method and rotary furnace method, and is more suitable for large-scale commercial mass production of new silicon-carbon negative electrode materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects and features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0024] Figure 1 A schematic diagram showing a structure of a production device for a controllable high-performance novel silicon-carbon negative electrode material according to an exemplary embodiment of the present invention;

[0025] Figure 2 A perspective structural diagram of the atmosphere chamber of the present invention is shown;

[0026] Figure 3 The SEM image of the novel silicon-carbon negative electrode material of Example 1 of the present invention is shown.

[0027] Description of main reference numerals:

[0028] 1-cracking chamber, 2-atmosphere chamber, 3-nested heating assembly, 4-limiting wheel, 5-gas pressure and concentration sensor, 6-online monitoring system, 7-motor, 8-pressure control system, 91-gas source cabinet, 92-flow meter, 10-lifting device, 11-thermal insulation layer, 12-inner cabin door, 13-outer cabin door, 14-incinerator. DETAILED DESCRIPTION

[0029] Hereinafter, a production device and method of a controllable high-performance novel silicon-carbon negative electrode material of the present invention will be described in detail in conjunction with the accompanying drawings and exemplary embodiments.

[0030] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "horizontal", "vertical", "top", "bottom", "inside", "outside", "front", "reverse", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] In the description of the present invention, unless otherwise specified, "multiple" and "several" mean two or more than two. In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Exemplary Embodiment 1

[0033] This exemplary embodiment provides a production device for a controllable high-performance new silicon-carbon negative electrode material.

[0034] Figure 1 A schematic diagram showing a structure of a production device for a controllable high-performance novel silicon-carbon negative electrode material according to an exemplary embodiment of the present invention; Figure 2 The perspective structural diagram of the atmosphere chamber of the present invention is shown. Figure 1 and Figure 2 To describe the production equipment of the controllable high-performance new silicon-carbon negative electrode material of this exemplary embodiment.

[0035] like Figure 1 and Figure 2 As shown in , the production equipment of the controllable high-performance new silicon-carbon negative electrode material mainly includes a cracking chamber 1, an atmosphere chamber 2, an online monitoring system 6, a pressure control system 8 and a gas source management system.

[0036] Wherein, the cracking cabin 1 is located in the atmosphere cabin 2, the cracking cabin 1 can rotate horizontally, and the material is subjected to a gas phase infiltration process in the cracking cabin 1. The pressure control system 8 is connected to the cracking cabin 1, and the gas source management system is connected to the cracking cabin 1. The pressure control system 8 is configured to perform intelligent pressure adjustment processing on the cracking cabin 1. The gas source management system is configured to input inert gas, or silane gas and inert gas, or carbon source gas and inert gas into the cracking cabin 1, and the pressure value of the cracking cabin 1 changes with a certain gradient. The online monitoring system 6 is configured to monitor the reaction safety threshold of the production equipment and control the siliconization amount.

[0037] In this exemplary embodiment, the pyrolysis chamber can adopt a gradient process. When pyrolysis is performed at a certain lower pressure value, the pressure value will rise, and when it rises to a certain threshold value, the pyrolysis is complete, and the pressure value is adjusted to the lower pressure value again, and the pyrolysis is repeated. This is a gradient process.

[0038] In this exemplary embodiment, the online monitoring system mainly monitors the pressure value change and threshold value of the cracking chamber, as well as the concentration change. The concentration change and the pressure value are linked, and dual parameter monitoring prevents process failure caused by sensor abnormality. The atmosphere chamber mainly monitors and maintains the inert gas pressure, and prevents silane gas leakage in the cracking chamber, so that hidden dangers can be discovered in time.

[0039] In this exemplary embodiment, the cracking chamber can adopt a shuttle structure with closed ends, and multiple gradient pressure environments can be achieved inside, or a conventional atmosphere environment can be achieved, and a special stirring plate structure is provided inside. The existing rotating and stirring structure can make the material react more evenly and with better consistency. The cracking chamber can adopt a furnace structure, and the internal pressure value can be as low as 2Pa. A low-pressure environment can greatly reduce the risk of cracking explosions. The cracking chamber adopts a special rotary furnace structure, and the upper limit of the speed can be 50Hz in a low-pressure environment.

[0040] In this exemplary embodiment, the cracking chamber can adopt a vertical or bedroom structure, and the temperature control area adopts three-temperature zone or multi-temperature zone heating to prevent the flow rate temperature difference from causing convection problems.

[0041] In this exemplary embodiment, an anti-floating powder structure may be provided at the external outlets at both ends of the cracking chamber. Since the carbon substrate has a small particle size and a bulk density and is easily carried out with the gas, this structure can effectively prevent the unreacted substrate material and the finished product from being doped.

[0042] In this exemplary embodiment, the material of the cracking chamber may include one or more of 304, 310, 310S, tungsten-lanthanum alloy and monel alloy, which can withstand high temperatures and corrosion, and is more conducive to achieving the effect of no impurities being brought in.

[0043] In this exemplary embodiment, serpentine and straight slatted material-cleaning plates may be used inside the cracking chamber, and the number of the material-cleaning plates may be 3 to 5.

[0044] In this exemplary embodiment, Figure 1 and 2 As shown in , a nested shaft may be provided at the left end of the cracking cabin 1, and the nested shaft passes through the atmosphere cabin 2 and is connected to the motor 7, and the motor 7 connects the atmosphere cabin 2 and the cracking cabin 1 through a shaft, and drives the cracking cabin 1 to rotate. The pressure control system is connected to the nested shaft, and the gas source management system is connected to the nested shaft. The pressure control system performs intelligent pressure control on the cracking cabin through the outer shaft (nested shaft) where the motor is located; the gas source management system can control the storage safety and flow threshold of the gas source. A sampler with a gas pressure and concentration sensor may be installed in the nested shaft, and is connected to the online monitoring system through the gas pressure and concentration sensor. Here, the gas pressure and concentration sensor may be an integrated sensor having the functions of a silane gas sensor and a pressure sensor.

[0045] Furthermore, if Figure 1 As shown in , the gas source management system may include a gas source cabinet 91 and a flow meter 92. The flow meter 92 is arranged on the outlet line of the gas source cabinet 91.

[0046] Further, the motor may include an explosion-proof DC variable frequency motor. The motor may be connected to the nested shaft in a meshing form via a coupler.

[0047] In this exemplary embodiment, a dust-proof device and a speed-changing device may be installed between the pressure control system and the pyrolysis chamber to prevent a large and rapid drop in pressure that would draw away a large amount of powder.

[0048] In this exemplary embodiment, the production equipment of the controllable high-performance new silicon-carbon negative electrode material may also include a carbon source gas sensor, a multi-point temperature sensor, a flow sensor and a speed controller; the carbon source gas sensor is located in the gas source management system, and the flow sensor is located at the gas source output end, and can be remotely controlled by the online monitoring system; the speed controller is located in the online monitoring system. In actual production, the operator only needs to be located at the online monitoring system to complete the setting of the process parameters. The temperature sensor is installed in the insulation layer in a multi-point multi-position mode, that is, installed in the thermal insulation layer of the atmosphere chamber; according to the length of the cracking chamber, 8 to 12 temperature sensor probes can be set on average, and their data ends are connected to the online monitoring system.

[0049] In this exemplary embodiment, the online monitoring system can be connected to various sensors in the production equipment through program control, and can remotely set and monitor the process program.

[0050] Furthermore, the online monitoring system can be combined with a computer via a PLC circuit for process control.

[0051] In this exemplary embodiment, Figure 1 As shown in , a gas pressure and concentration sensor 5 may be installed on the top of the atmosphere chamber 2 , and the gas pressure and concentration sensor 5 is connected to the online monitoring system 6 .

[0052] In this exemplary embodiment, the atmosphere chamber is an inert gas environment, which can prevent the polycondensation reaction in the cracking chamber from causing an explosion. The atmosphere chamber can provide an inert environment protection for the cracking chamber. Figure 2 As shown in the figure, the cabin of the atmosphere cabin may include a metal layer, a heat insulation layer 11 and a nested heating assembly 3 arranged from the outside to the inside. The heat insulation layer is laid on the inner wall of the atmosphere cabin; the nested heating assembly is fixed on the inner wall of the atmosphere cabin, surrounding the cracking cabin but not in contact, as contact will cause a short circuit; and the metal layer is arranged on the outer surface of the cabin wall.

[0053] Further, the material of the outermost metal layer may include one or more of 304, 310, 310S, tungsten-lanthanum alloy and monel alloy. The material of the heat-insulating layer of the middle layer may include one or more of aluminum silicate fiber, aluminum oxide fiber, composite carbon fiber, quartz sand and casting material. The material of the innermost nested heating component 3 may include one or more of iron-chromium-aluminum alloy strip, nickel-chromium alloy strip, tungsten strip, molybdenum strip and molybdenum-yttrium strip.

[0054] In this exemplary embodiment, a water cooling circulation facility can be set in the atmosphere cabin wall to speed up the time for the production equipment to drop from 300°C to 80°C. Dropping from the preset temperature to 300°C is generally relatively fast, while spontaneous cooling at 300°C under room temperature is very time-consuming. Due to the presence of silicon infiltration, when the pressure changes significantly, the material will spontaneously ignite as long as it comes into contact with air, which requires the cabin temperature to drop to a sufficiently low level.

[0055] In this exemplary embodiment, the pressure control system may include one or more of a slide valve pump, a rotary vane pump, a screw pump, and a Roots pump, and others may also be used. The pressure control system adopts a multi-stage pump combination form.

[0056] In this exemplary embodiment, Figure 2 As shown in , a plurality of limiting wheels 4 may be installed at the bottom of the cracking chamber 1. The limiting wheels provide the support and limiting required for the rotation of the cracking chamber.

[0057] Furthermore, 4 to 6 limiting wheels may be provided at the bottom of the pyrolysis chamber.

[0058] In this exemplary embodiment, Figure 1 As shown in the figure, a lifting device 10 may be provided at the bottom of the atmosphere chamber 2, and horizontal rotation, premixing, and feeding and discharging of the cracking chamber can be achieved by lifting. Batch mixing and / or feeding and discharging of samples (materials and / or products) can be achieved by using a lifting device (lifting platform) and forward and reverse rotation of the motor.

[0059] In this exemplary embodiment, Figure 1 As shown in FIG. 1 , the right end of the atmosphere chamber 2 is provided with an openable and closable outer chamber door 13. Figure 2 As shown in, the right end of the cracking chamber 1 can be provided with an openable and closable inner door 12. Here, the inner and outer doors can be used for the entry and exit of materials and products before and after the reaction.

[0060] In this exemplary embodiment, Figure 1 and Figure 2 As shown in the figure, the inner door 12 can be connected to the ball valve and the incinerator 14 in sequence through pipelines. Specifically, the center of the inner door can be connected to the ball valve (tail ball valve) and the incinerator through a pipeline, and the center of the door can have an axial pipe with a ball valve and connected to the incinerator. Here, the incinerator can be used for tail gas treatment of the secondary coating of the siliconized precursor.

[0061] In this exemplary embodiment, the gas source management system may include a gas source, a special gas cabinet, a special gas pipeline, a silane mass flow meter, a special pipeline seal, a silane-specific gas valve, a carbon source gas pipeline connector, a vacuum exhaust facility, and an online leakage monitoring facility. Among them, the special gas cabinet is dedicated to silane gas and has a pipeline emptying function; the carbon source gas pipeline connector is a conventional 304 material accessory; the vacuum exhaust facility is used to empty the pipeline impurity gas when switching the silane gas source; the silane-specific gas valve and connector are Swagelok explosion-proof special accessories; the online leakage monitoring facility is used to monitor the leakage safety threshold during the transportation of silane and carbon source gas. Here, the component structure of the gas source management system is a safety structure inherent in the transportation of special gases.

[0062] Exemplary Embodiment 2

[0063] This exemplary embodiment provides a method for producing a controllable high-performance novel silicon-carbon negative electrode material.

[0064] The production method of the controllable high-performance new silicon-carbon negative electrode material of this exemplary embodiment can be implemented by the production equipment of the controllable high-performance new silicon-carbon negative electrode material described in the above exemplary embodiment 1, and the production method may include the following steps:

[0065] S1, open the outer door and the inner door, load a certain amount of carbon substrate (the amount of carbon substrate added is 10-95% of the volume of the cracking chamber) into the cracking chamber, close the inner and outer doors, close the ball valve at the outer door, open the pressure control system, and adjust the pressure of the cracking chamber to P1 (1-100Pa). Here, if the carbon substrate is excessive, it will cause serious powder blowing and uneven coating caused by insufficient material lifting.

[0066] S2. Edit the process through the online monitoring system, start the cracking chamber rotation, adjust the equipment (cracking chamber) temperature to the preset temperature A (500-650°C) and keep it warm, and adjust the pressure again to make the pressure value reach P2 (1-50Pa). Here, rotation can make the powder temperature rise evenly. Temperature is the key factor in controlling cracking. After heating, the pressure value will rise and the pressure needs to be adjusted again. Rotation during cracking can also ensure the consistency of siliconization.

[0067] S3, the gas source delivery pipeline of the gas source management system is emptied and replaced, and inert gas D and silane gas are introduced into the cracking chamber at a slow flow rate and a certain mass X (silane mass), and the pressure change gradient of the cracking chamber is controlled to be △P (△P is 100Pa), and the pressure gradient is changed according to the control pressure gradient △P, 2△P, 3△P and other gradients, and the cracking is carried out at temperature A for a duration of T1 (2 to 20 hours) to obtain silicon-carbon precursors with different siliconization amounts. Among them, the mass X, that is, the mass of silane, is 30 to 100% of the carbon substrate. Here, the flow rate is related to the volume of the cracking chamber, the number of carbon substrates and the gradient pressure value, and needs to be converted; the mixed gas flow rate is generally roughly calculated as 1%*cracking chamber volume / min, where the limiting condition is that the maximum flow rate of silane does not exceed 20000SCCM. It should also be noted that the present invention adopts a gradient process. When cracking is carried out at a certain lower limit pressure value, the pressure value will rise, and the cracking is complete when it rises to a certain threshold value, and the pressure value is adjusted to the lower limit pressure value again, and the cracking is repeated. This is a gradient process.

[0068] S4. The delivery of inert gas D and silane gas can be stopped through the online monitoring system, and the pipeline is cleaned again. After the inert gas D is introduced to make the cracking chamber slightly positive pressure (greater than atmospheric pressure 0.1-0.3Kpa), the ball valve at the outer door is opened to start the incinerator. The temperature of the cracking chamber is adjusted to the preset temperature B (500-700°C) and kept warm, and the carbon source gas C and inert gas D are introduced for secondary coating. The coating time is T2 (1-5 hours) to obtain a new silicon-carbon negative electrode material.

[0069] S5. Turn off the carbon source gas supply, maintain and reduce the flow rate of inert gas D, wait until the temperature of the production equipment drops below 80°C, open the lifting platform, and rotate the cracking chamber to collect the product. Here, maintain an oxygen-free environment in the chamber, and generally reduce the flow rate of inert gas D to 1000-3000 SCCM.

[0070] In this exemplary embodiment, in step S3, the pressure change gradient may include gradients of 100 Pa, 200 Pa and 300 Pa. The specific process of pressure change may include: by slowly delivering a mixture of silane and inert gas, the pressure value in the cracking chamber is continuously increased, wherein a rise of 100 Pa is a gradient, and the number of gradient layers is controlled to accurately control the amount of siliconization, and all the increased gradients are maintained under the low pressure condition of the cracking chamber.

[0071] In this exemplary embodiment, in step S1, the carbon substrate may include one or more of resin carbon, biomass carbon, pitch carbon and coke. Here, the biomass carbon may include plant or biological carbon material products such as coconut shell carbon.

[0072] Furthermore, the carbon base raw material may be spherical or quasi-spherical porous carbon.

[0073] In this exemplary embodiment, in steps S1 to S5, the inert gas present may include one or more of nitrogen, argon, helium and carbon dioxide.

[0074] In this exemplary embodiment, in step S3, the silane concentration of the mixed gas of the inert gas and the silane gas may be 2 to 100%, which means that the volume ratio of the silane gas to the inert gas is 2 to 100%.

[0075] In this exemplary embodiment, in step S4, the carbon source gas may include one or more of methane, ethane, propane, ethylene, propylene and acetylene. The carbon source concentration of the mixed gas of inert gas and carbon source gas is 20-66%. This means that the volume ratio of carbon source gas to inert gas is 20-66%. For example, the mixed gas of propylene and acetylene may have a mixing ratio of 1.5-3:7. The use of mixed hydrocarbon coating can reduce the risk of rapid polycondensation explosion of a single carbon source gas and increase the density of the coating.

[0076] In this exemplary embodiment, in step S4, after the reaction is finished, the seals connecting the atmosphere chamber and the cracking chamber can be opened to restore the cracking chamber to normal pressure or slightly positive pressure, the outer and inner doors can be opened, and the lifting device and the motor can be turned on to collect the materials. Here, a special collector can be engaged with the inner hatch to avoid dust pollution, and a specially customized screw propeller can also be set for feeding.

[0077] In this exemplary embodiment, in the production method, the exhaust gas separated from the siliconizing process and the secondary coating process can be transported to an incinerator via an induced draft fan for combustion treatment, so as to achieve safe and environmentally friendly emission and harmless treatment of the exhaust gas.

[0078] In order to better understand the above exemplary embodiments of the present invention, they are further described below in conjunction with specific examples.

[0079] Example 1

[0080] The production method of the controllable high-performance new silicon-carbon negative electrode material is realized by the production equipment of the controllable high-performance new silicon-carbon negative electrode material to prepare the controllable high-performance new silicon-carbon negative electrode material. Specifically, the following steps may be included:

[0081] S1. Use a screw propeller to transport resin-based porous carbon with a particle size range of 3 to 8 um into the cracking chamber, close the inner and outer doors of the cracking chamber, and close the ball valve at the tail gas end. Start nitrogen replacement in the atmosphere chamber to reduce the oxygen content in the atmosphere chamber to below 0.001%. Start cleaning and nitrogen replacement in the cracking chamber, repeat three times, and maintain the pressure of the cracking chamber below 50 Pa.

[0082] S2. Turn on the heating and motor to raise the temperature of the cracking chamber to 550°C and adjust the pressure value to 5Pa again.

[0083] S3, silane and nitrogen mixed gas (flow ratio 1:20) enters the cracking chamber through the flow meter, and the pressure rises by 200Pa as a gradient, and the siliconization is circulated. After the reaction is completed (reaching the upper limit threshold), the pressure value is adjusted to 5Pa. Repeat this cycle, and according to the total flow, the total consumption mass of silane gas is controlled to be 30% of the carbon substrate, and the number of cycles is calculated.

[0084] S4. After the siliconization rounds are completed, the pressure value of the cracking chamber is adjusted to below 5Pa, and then three nitrogen replacements are performed to make the cracking chamber positive pressure (for example, 0.2-0.32mPa to prevent backflow). At this time, keep the nitrogen in, open the tail ball valve and the incinerator. Control the equipment to heat up to 700℃. A mixture of nitrogen, acetylene and propylene (flow ratio 30:7:3) enters the cracking chamber through a flow meter, and the total mass of the carbon source gas is controlled to be 7% of the siliconization precursor material, and the flow rate is 0.1 tube length / second, and the siliconization precursor is coated twice. It should be noted that for different carbon source gases, the carbon coating amount can be calculated more accurately according to the cracking rate and quality. The concentration of the carbon source gas affects its cracking rate and the air intake per unit time. By adjusting the time, a fixed carbon loading amount can be achieved. In actual production, the process is generally completed by adjusting the time, and the concentration / flow / temperature can be used as a secondary variable.

[0085] S5. After the coating is completed, nitrogen is purged until the temperature of the chamber drops to 80°C. The reaction is completed and the material is taken out. The morphology of the obtained new silicon-carbon negative electrode material can be found in Figure 3 The tail gas generated by the reaction can be burned in an incinerator to achieve safe and environmentally friendly emission.

[0086] After testing, it is found that Example 1 can realize mass production of high-performance new silicon-carbon negative electrode materials, the material loss rate of the new silicon-carbon material is extremely low, the particle size range of the prepared new silicon-carbon negative electrode material can be 5 to 8 um, and no impurities are introduced.

[0087] Example 2

[0088] The novel silicon-carbon negative electrode material is prepared by referring to the production method of the controllable high-performance novel silicon-carbon negative electrode material of Example 1, except that the total mass of the silane gas is increased to 50% of the carbon substrate.

[0089] Example 3

[0090] The novel silicon-carbon negative electrode material is prepared by referring to the production method of the controllable high-performance novel silicon-carbon negative electrode material of Example 1, except that the carbon substrate is replaced with a biomass carbon substrate.

[0091] Example 4

[0092] The novel silicon-carbon negative electrode material is prepared by referring to the production method of the controllable high-performance novel silicon-carbon negative electrode material of Example 2, except that the carbon substrate is replaced with a biomass carbon substrate.

[0093] Test cases 1 to 3

[0094] Several new silicon-carbon products on sale or in the market (for example, the silicon-carbon products of Test Examples 1 to 3 may be provided with product codes: WSC1900, LSC20 and TSC1700) were taken for conventional physical and chemical tests and electrochemical performance tests. The comprehensive test results can be seen in Table 1 below, which shows that the present invention can prepare and batch prepare new silicon-carbon negative electrode materials with high performance and excellent microstructure.

[0095] Table 1 Results of conventional physical and chemical tests and electrochemical performance tests

[0096]

[0097] In summary, the advantages proposed by the present invention include at least one of the following:

[0098] (1) The production equipment of the controllable high-performance new silicon-carbon negative electrode material proposed in the present invention produces and prepares the silicon-carbon negative electrode material under a gradient process, which greatly reduces the problem of sudden explosion in the reaction stage.

[0099] (2) The production equipment of the controllable high-performance new silicon-carbon negative electrode material proposed in the present invention can perform harmless treatment on tail gas and recycle the unreacted particles.

[0100] (3) Since the production method of the controllable high-performance new silicon-carbon negative electrode material proposed in the present invention adopts a pressure gradient siliconization process, the siliconization amount and siliconization area can be strictly controlled, and the particle size of the obtained product is basically consistent with the carbon substrate, and there will be no serious surface area silicon phenomenon or carbon encapsulation problem of micron silicon particles.

[0101] Although the above has described the production equipment and method of a controllable high-performance new silicon-carbon negative electrode material of the present invention in combination with exemplary embodiments, those skilled in the art should be aware that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A production device for a controllable high-performance new silicon-carbon negative electrode material, characterized in that: The production equipment includes a cracking chamber, an atmosphere chamber, an online monitoring system, a pressure control system and a gas source management system, wherein: The cracking chamber is located in the atmosphere chamber and can rotate horizontally; the pressure control system and the gas source management system are both connected to the cracking chamber; the pressure control system is configured to adjust the pressure of the cracking chamber, and the gas source management system is configured to input inert gas, or silane gas and inert gas, or carbon source gas and inert gas into the cracking chamber. The pressure value of the cracking chamber changes with a certain gradient, and the online monitoring system is configured to monitor the reaction safety threshold of the production equipment and control the amount of silicon penetration.

2. The production equipment of the controllable high-performance new silicon-carbon negative electrode material according to claim 1 is characterized in that: A nested shaft is provided at one end of the cracking chamber, the nested shaft passes through the atmosphere chamber and is connected to the motor, the pressure control system and the gas source management system are both connected to the nested shaft, a sampler of a gas pressure and concentration sensor is provided in the nested shaft and is connected to the online monitoring system.

3. The production equipment of the controllable high-performance new silicon-carbon negative electrode material according to claim 1 is characterized in that: The cabin body of the atmosphere cabin comprises a metal layer, a heat insulation layer and a nested heating assembly from the outside to the inside; a gas pressure and concentration sensor is installed on the top of the atmosphere cabin, and the gas pressure and concentration sensor is connected to an online monitoring system.

4. The production equipment of the controllable high-performance new silicon-carbon negative electrode material according to claim 1 is characterized in that: A plurality of limiting wheels are arranged at the bottom of the cracking chamber to provide the support and limiting required for the rotation of the cracking chamber.

5. The production equipment of the controllable high-performance new silicon-carbon negative electrode material according to claim 1 is characterized in that: A lifting device is arranged at the bottom of the atmosphere chamber.

6. The production equipment of the controllable high-performance new silicon-carbon negative electrode material according to claim 1, characterized in that: An outer door is arranged at one end of the atmosphere cabin, and an inner door is arranged at one end of the cracking cabin, and the outer door and the inner door are in the same direction.

7. The production equipment of the controllable high-performance new silicon-carbon negative electrode material according to claim 6 is characterized in that: The inner door is connected with a ball valve and an incinerator in sequence through pipelines.

8. A method for producing a new type of controllable high-performance silicon-carbon negative electrode material, characterized in that: The production method is implemented by a production device for a controllable high-performance novel silicon-carbon negative electrode material according to any one of claims 1 to 7, and the production method comprises the following steps: S1. Load the carbon substrate into the cracking chamber and adjust the pressure of the cracking chamber to 1-100 Pa; the amount of the carbon substrate added is 10-95% of the volume of the cracking chamber; S2, rotating the cracking chamber, and keeping the temperature at 500-650°C, and adjusting the pressure again to control the pressure value to 1-50Pa; S3, introducing inert gas and silane gas into the cracking chamber, controlling the pressure gradient of the cracking chamber, and carrying out the process for 2 to 20 hours to obtain silicon-carbon precursors with different siliconization amounts; the mass of silane is 30 to 100% of the carbon substrate; S4. After introducing inert gas to make the cracking chamber slightly positive pressure, adjust the temperature of the cracking chamber to 500-700° C. and keep it warm, introduce carbon source gas and inert gas for secondary coating, the coating time is 1-5 hours, and obtain a new silicon-carbon negative electrode material.

9. The method for producing a controllable high-performance novel silicon-carbon negative electrode material according to claim 8, characterized in that: The pressure change gradient includes 100Pa, 200Pa and 300Pa.

10. The method for producing a controllable high-performance novel silicon-carbon negative electrode material according to claim 8, characterized in that: The carbon substrate includes one or more of resin carbon, biomass carbon, asphalt carbon and coke; the inert gas includes one or more of nitrogen, argon, helium and carbon dioxide; the silane concentration of the mixed gas of the inert gas and silane gas is 2 to 100%; the carbon source gas includes one or more of methane, ethane, propane, ethylene, propylene and acetylene; the carbon source concentration of the mixed gas of the inert gas and carbon source gas is 20 to 66%.

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