Fluidized bed reactor for improving silicon-carbon negative electrode uniformity
Patent Information
- Application Number
- CN202522019146.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-18
- Publication Date
- 2026-09-22
- Estimated Expiration
- 2035-09-18
AI Technical Summary
[0003]然而，当处理粒径小于50μm的微米级硅碳材料或多孔碳材料颗粒时，其高比表面积导致颗粒间范德华力显著增强，易引发严重团聚，从而产生沟流(气体短路)和节涌(气泡合并)等非正常流化现象
[0025]本实用新型实施例提供的用于改善硅碳负极均一性的流化床反应器，通过切向湍流发生装置在床层高度60％–90％区域注入切向湍流气流，能够有效增加床层上部的紊动程度并彻底击碎顶部团聚体，从而改善颗粒的分散状态。并且，在优选的方案中，可通过沿流化床反应器筒体底部周向均匀分布的多个第二进气管提供底部多向对冲气流。可进一步形成高强度剪切涡旋，实现颗粒的原位分散，替代机械搅拌实现颗粒原位分散，并有效避免搅拌桨叶机械卡死的问题；通过在第一进气管的出气端的管壁上设置均匀的多个气孔提供底部横向吹穿气流，能够防止局部死角的产生，保证气固接触的充分性。通过上述多气流场的协同作用，实现了床层全域流态的重构，在硅碳负极制备中，能够使硅在多孔碳颗粒中的沉积均匀性提升至99％以上，实现硅碳负极材料的连续稳定生产。
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Figure CN224777987U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of powder dispersion equipment technology, and in particular to a fluidized bed reactor for improving the uniformity of silicon-carbon anodes. Background Technology
[0002] Silicon-carbon anode materials are considered a key direction for improving the energy density of lithium-ion batteries due to their breakthrough high specific capacity. In recent years, their market penetration rate has expanded rapidly at an average annual rate of approximately 35%, and global demand is projected to exceed 500,000 tons by 2030. To achieve the large-scale preparation of silicon-carbon composite materials, chemical vapor deposition (CVD) technology has gradually become the industry's recognized core process. CVD enables the nanoscale controllable deposition of silicon within the pore structure of porous carbon supports, thereby effectively improving the structural stability and electrochemical performance of silicon-carbon materials. As the core equipment of the CVD process, fluidized bed reactors, with their excellent gas-solid contact efficiency and mass transfer characteristics, have become the preferred choice for the industrial deposition of silicon-carbon composite materials.
[0003] However, when processing micron-sized silicon-carbon materials or porous carbon materials with a particle size of less than 50 μm, their high specific surface area leads to a significant enhancement of the van der Waals forces between particles, which easily causes severe agglomeration, resulting in abnormal fluidization phenomena such as channeling (gas short-circuiting) and throttling (bubble merging).
[0004] To address this issue, the industry generally adopts built-in mechanical stirring to alleviate agglomeration. However, this solution has inherent drawbacks: the shear force generated by stirring decreases rapidly with the bed height, making it difficult to cover the entire bed and ultimately leading to uneven deposition and the formation of "dead zones." In addition, because the particles continuously impact the stirring blades in a high-density fluidized state, mechanical jamming is easily caused, with a monthly failure rate exceeding 15%, which greatly affects the continuous and stable operation of the reaction system. Utility Model Content
[0005] The purpose of this invention is to provide a fluidized bed reactor for improving the uniformity of silicon-carbon anodes. By improving the structure of the fluidized bed reactor, tangential turbulent airflow is injected into the upper part of the bed to effectively break up the top agglomerates. Combined with the bottom counterflow airflow and the lateral blowing airflow, the particles are dispersed throughout the entire process, the deposition uniformity is significantly improved, and mechanical jamming is avoided, ensuring the stable production of silicon-carbon anodes.
[0006] To achieve the above objectives, this utility model provides a fluidized bed reactor for improving the uniformity of silicon-carbon anodes, the fluidized bed reactor comprising:
[0007] A fluidized bed reactor shell includes a feed inlet and a discharge outlet; the feed inlet is located on the top or side wall of the fluidized bed reactor shell; the discharge outlet is located at the bottom of the fluidized bed reactor shell.
[0008] The chassis is detachably mounted on the feed inlet of the fluidized bed reactor cylinder;
[0009] The first air inlet pipe is installed on the chassis, and the air outlet of the first air inlet pipe is located inside the fluidized bed reactor cylinder.
[0010] A tangential turbulence generator is installed on the upper side wall of the fluidized bed reactor cylinder. The outlet direction of the nozzle of the tangential turbulence generator is inclined upward relative to the radial plane of the fluidized bed reactor cylinder and is tangentially set at 15°-75° with the side wall. Tangential airflow is injected in the region of 60%-90% of the bed height.
[0011] Preferably, there are multiple tangential turbulence generators, which are evenly distributed around the perimeter of the fluidized bed reactor cylinder.
[0012] More preferably, there are three tangential turbulence generators.
[0013] Preferably, multiple air holes are evenly distributed on the wall of the air outlet end of the first air inlet pipe, and the air holes eject airflow that penetrates laterally from the center of the chassis to the side wall of the cylinder.
[0014] Preferably, the fluidized bed reactor further includes a rotating device, the rotating device comprising:
[0015] The drive unit is located below the chassis and is connected to the lower end of the first air intake pipe via a connecting part;
[0016] The control unit is connected to and drives the drive unit to rotate, thereby causing the first air intake pipe or the air outlet of the first air intake pipe to rotate.
[0017] Preferably, the fluidized bed reactor further includes multiple second air inlet pipes;
[0018] Multiple second air inlet pipes are evenly distributed circumferentially along the bottom of the fluidized bed reactor cylinder;
[0019] The outlet of each second air inlet pipe is inclined downwards at 15°-75° toward the bottom of the fluidized bed reactor cylinder, and the airflow ejected from the outlet forms a multi-directional jet that counteracts each other at the bottom of the fluidized bed reactor.
[0020] More preferably, there are 3-8 second air intake pipes.
[0021] Preferably, the fluidized bed reactor further includes a stirring paddle; the stirring paddle is disposed at the bottom of the fluidized bed reactor cylinder.
[0022] Preferably, the fluidized bed reactor further includes a heating device; the heating device is disposed outside the fluidized bed reactor cylinder and is attached to the outer wall of the fluidized bed reactor cylinder.
[0023] Preferably, the chassis is opened and closed by a snap-on mechanical switch or by a cylinder.
[0024] The chassis opens from the discharge port to discharge material into the fluidized bed reactor cylinder, or the chassis closes to the discharge port to seal the bottom of the fluidized bed reactor cylinder.
[0025] The fluidized bed reactor for improving the uniformity of silicon-carbon anodes provided in this embodiment injects tangential turbulent airflow into the 60%–90% region of the bed height using a tangential turbulence generator. This effectively increases the turbulence in the upper part of the bed and thoroughly breaks up top agglomerates, thereby improving particle dispersion. Furthermore, in a preferred embodiment, multiple second air inlets evenly distributed circumferentially along the bottom of the fluidized bed reactor cylinder provide multi-directional counter-current airflow at the bottom. This further generates high-intensity shear vortices, achieving in-situ particle dispersion, replacing mechanical stirring, and effectively avoiding the problem of mechanical jamming of the stirring blades. Multiple uniformly distributed air holes on the pipe wall at the outlet end of the first air inlet provide lateral blowing airflow at the bottom, preventing the formation of local dead zones and ensuring sufficient gas-solid contact. Through the synergistic effect of the above-mentioned multi-flow fields, the entire flow pattern of the bed is reconstructed. In the preparation of silicon-carbon anodes, the deposition uniformity of silicon in porous carbon particles can be improved to over 99%, achieving continuous and stable production of silicon-carbon anode materials. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the structure of a fluidized bed reactor for improving the uniformity of silicon-carbon anodes, provided in an embodiment of the present invention.
[0027] Figure 2 A schematic diagram of the bottom partial structure of the fluidized bed reactor provided in an embodiment of this utility model;
[0028] Figure 3 This is a schematic diagram of another modified structure of the fluidized bed reactor for improving the uniformity of silicon-carbon anodes, provided as an embodiment of the present invention. Detailed Implementation
[0029] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments.
[0030] This utility model provides a fluidized bed reactor for improving the uniformity of silicon-carbon anodes, such as... Figure 1 As shown, Figure 1 The arrows in the diagram indicate the airflow direction. A fluidized bed reactor includes:
[0031] The fluidized bed reactor shell 1 includes a feed inlet (not shown in the figure) and a discharge inlet (not shown in the figure). The feed inlet can be located on the top or side wall of the fluidized bed reactor shell 1, and preferably, a feed electric control valve can be installed inside the feed inlet to control the feed rate. The discharge inlet is located at the bottom of the fluidized bed reactor shell.
[0032] The chassis 2 is detachably mounted on the feed inlet at the bottom of the fluidized bed reactor cylinder 1.
[0033] The chassis 2 can be opened and closed by a snap-on mechanical switch or by a cylinder; the chassis 2 can be opened from the discharge port to discharge the material inside the fluidized bed reactor cylinder 1, or the chassis 2 can be closed at the discharge port to seal the bottom of the fluidized bed reactor cylinder 1.
[0034] The first air inlet pipe 3 is installed on the chassis 2, and the outlet end of the first air inlet pipe is located inside the fluidized bed reactor cylinder 1. The first air inlet pipe 3 is used to introduce the reaction gas and the carrier gas, that is, to introduce the main fluidizing gas.
[0035] A tangential turbulence generator 4 is installed on the upper side wall of the fluidized bed reactor shell 1. The outlet direction of the nozzle of the tangential turbulence generator 4 is inclined upward relative to the radial plane of the fluidized bed reactor shell 1 and is tangentially set at 15°-75° to the side wall, i.e., the outlet direction is at 15°-75° with the tangential direction of the side wall; more preferably, it is 30°-60°, specifically 30°, 45° or 60°. The tangential turbulence generator 4 is used to inject high-speed tangential airflow into the region of 60%-90% of the bed height.
[0036] Multiple tangential turbulence generators 4 can be evenly distributed along the circumference of the fluidized bed reactor cylinder. Preferably, there are 2-4, more preferably 3.
[0037] The tangential turbulence generator 4 induces a strong turbulence zone with a Reynolds number > 5000 in the upper part of the cylinder by injecting a high-speed tangential airflow in the 60%–90% region of the bed height, creating intense rotational turbulence. On the one hand, this turbulence effectively breaks up agglomerates formed in the top region during particle ascent and promotes their redispersibility; on the other hand, the interaction between the tangential airflow and the main fluidizing gas flow enhances bed turbulence and circulation, avoiding the formation of a "static zone" or "pseudo-fluidized zone" at the top, thereby improving gas-solid contact efficiency. Under this effect, particles maintain a good dispersion state throughout the entire bed, resulting in a more uniform deposition process.
[0038] In an alternative approach, conventional agitators can be installed in the fluidized bed reactor, such as... Figure 3As shown, the stirring paddle 6 applies shear force to the bed particles through mechanical agitation during operation, thereby weakening the van der Waals forces between particles and reducing agglomeration.
[0039] In another alternative solution, such as Figure 1 , Figure 2 Instead of a conventional stirring paddle, the fluidized bed reactor has multiple (e.g., 3-8) second air inlets 5 evenly distributed around the bottom of the fluidized bed reactor cylinder 1. The outlet of each second air inlet 5 is inclined downwards towards the bottom of the fluidized bed reactor cylinder 1 at an angle of 15°-75° (preferably 30°-60°, specifically 30°, 45° or 60°) to the cylinder. The airflow ejected from the outlet forms a multi-directional jet that counteracts each other at the bottom of the fluidized bed reactor.
[0040] The multi-directional jets generated by multiple second air inlets 5 can produce high-intensity shear and disturbance at the bottom of the bed, effectively breaking up particle accumulation and preventing the formation of dead zones. At the same time, it enhances the fluid circulation of the bottom particles, providing uniform gas-solid distribution conditions for the upper bed, thereby improving particle dispersion and silicon deposition uniformity, and realizing stable and continuous operation of the fluidized bed.
[0041] The gas used to generate the aforementioned tangential turbulence and mutually opposing multi-directional jets can be an inert gas, such as nitrogen or argon.
[0042] In a more preferred embodiment, such as Figure 2 As shown, multiple air holes 31 are evenly distributed on the wall of the outlet end of the first air inlet pipe 3. An airflow, flowing laterally from the center of the chassis to the side wall of the cylinder, is ejected through these air holes 31. This laterally blowing airflow further breaks up the localized accumulation of particles at the bottom, preventing the formation of dead zones or gas channel deviation. Simultaneously, it increases lateral disturbance and circulation at the bottom of the bed, contributing to the uniform distribution of particles throughout the entire bed. Figure 2 The arrows in the diagram indicate the direction of airflow.
[0043] Optionally, the fluidized bed reactor further includes a rotating device (not shown in the figure), which includes: a drive unit disposed below the chassis and connected to the lower end of the first inlet pipe via a connecting part; and a control unit connected to and driving the drive unit to rotate, thereby rotating the first inlet pipe or its outlet end. In the scheme where the outlet end is driven to rotate independently, the outlet end of the first inlet pipe can adopt a rotatable sleeve structure. By adding a rotating device, the airflow ejected from the first inlet pipe can form a sweeping effect at the bottom of the bed, expanding the airflow coverage area and making the bottom particles more uniformly stressed.
[0044] The fluidized bed reactor proposed in this embodiment may also include a heating device (not shown in the figure); the heating device is disposed outside the fluidized bed reactor shell and is attached to the outer wall of the fluidized bed reactor shell. The heating device maintains a suitable temperature inside the fluidized bed reactor.
[0045] The following describes a specific working process of the fluidized bed reactor of this application in a silicon deposition process in porous carbon, using a structure that does not have a conventional stirring paddle but has a second air inlet pipe as an example.
[0046] 1. Feeding:
[0047] The pretreated porous carbon matrix powder is fed into the fluidized bed chamber through the feed inlet, and the powder naturally accumulates at the bottom of the chamber to form an initial powder bed.
[0048] 2. Fluidized bed start-up:
[0049] Turn on the heating device to gradually raise the chamber temperature to the set reaction temperature. A mixture of silane and nitrogen is introduced through multiple evenly distributed pores on the wall of the first air inlet pipe at the bottom of the cylinder to form the main atmosphere for the deposition reaction and to create a transverse airflow to prevent localized particle accumulation.
[0050] 3. Airflow dispersion and homogenization:
[0051] Nitrogen gas is introduced through a tangential turbulence generator installed on the upper side wall of the cylinder to form tangential turbulence, thereby creating a ring-shaped vortex field that effectively disperses the powder bed and promotes uniform dispersion of particles. At the same time, gas entering through the second air inlet pipe at the bottom of the cylinder generates multi-directional jets that counteract each other, further preventing the accumulation of particles at the bottom and avoiding dead zones, thus enhancing the fluidization effect of the powder.
[0052] 4. Deposition reaction:
[0053] Under the combined action of multiple airflows, the powder is in a stable suspended fluidized state. Within the set process time, silane gas decomposes and is uniformly deposited on the porous carbon surface and inside the pores, thereby obtaining a uniform silicon-carbon composite structure.
[0054] 5. Feeding:
[0055] After deposition, the heating device and air intake are turned off, and the exhaust device is activated to remove residual gas and perform dust removal. Then, the bottom feed port is opened, and the deposited porous silicon-carbon anode material is discharged by airflow or gravity and enters the collection device.
[0056] To better illustrate the function and effect of the fluidized bed reactor proposed in this application, the following comparative description is provided using two examples and two comparative examples of silicon-carbon anode materials.
[0057] Example 1
[0058] Porous carbon matrix powder is placed in a fluidized bed reactor equipped with multiple second air inlets and without a stirring paddle. The powder naturally accumulates at the bottom of the chamber to form an initial powder bed.
[0059] Before starting, nitrogen gas is introduced into the cylinder to replace the air and create a protective atmosphere. The heating device is then activated to raise the temperature inside the cylinder to the reaction temperature of 540°C.
[0060] A mixture of silane and nitrogen at a flow rate of 20 L / min is introduced through the air holes (3 mm in diameter, 3 mm spacing between adjacent air holes, in two rows) at the outlet end of the first air inlet pipe at the bottom of the cylinder. This mixture serves not only as a reactant gas but also as a bottom transverse blow-through gas flow. Simultaneously, nitrogen is introduced through three tangential turbulence generators evenly arranged around the circumference at the top of the cylinder at a flow rate of 50 L / min, forming tangential turbulence in the 60%–90% bed height region. At the same time, nitrogen at a flow rate of 100 L / min is introduced through four second air inlets evenly spaced along the sidewall at the bottom, forming a counter-current jet.
[0061] Through the synergistic effect of multiple airflows, the powder maintains a stable suspended fluidized state. During the 5-hour deposition reaction, silane decomposes and is uniformly deposited on the surface and inside the pores of the porous carbon matrix, ultimately yielding a porous silicon-carbon anode material with a carbon content of 47.6 wt%.
[0062] Carbon coating was applied to the deposited porous silicon-carbon material. A mixture of acetylene and nitrogen was used as the carbon source, with an acetylene flow rate of 5 L / min and a nitrogen flow rate of 45 L / min. The coating process was carried out at 550 °C for 3 hours, resulting in a carbon-coated porous silicon-carbon anode material.
[0063] Example 2
[0064] Porous carbon matrix powder is placed in a fluidized bed reactor equipped with a stirring paddle, and the powder naturally accumulates at the bottom of the chamber to form an initial powder bed.
[0065] Before starting, nitrogen gas is introduced into the cylinder to replace the air and create a protective atmosphere. The heating device is then activated to raise the temperature inside the cylinder to the reaction temperature of 540°C.
[0066] A mixture of silane and nitrogen at a flow rate of 20 L / min is introduced through the air holes (3 mm in diameter, 3 mm spacing between adjacent air holes, in two rows) at the outlet end of the first air inlet pipe at the bottom of the cylinder. This mixture serves not only as a reactant gas but also as a bottom transverse blowing gas. Simultaneously, nitrogen is introduced through three tangential turbulence generators evenly arranged on the same circumference at the top of the cylinder at a flow rate of 50 L / min, forming tangential turbulence in the 60%–90% bed height region. At the same time, the bottom stirring impeller disperses the powder bed at a speed of 70 rpm, maintaining the fluidized state of the powder.
[0067] Through the combined effects of transverse airflow, tangential turbulence, and stirring paddle, the powder maintains a stable suspended fluidized state. During the 5-hour deposition reaction, silane decomposes and is uniformly deposited on the surface and inside the pores of the porous carbon matrix, ultimately yielding a porous silicon-carbon anode material with a carbon content of 48.5 wt%.
[0068] Carbon coating was applied to the deposited porous silicon-carbon material. A mixture of acetylene and nitrogen was used as the carbon source, with an acetylene flow rate of 5 L / min and a nitrogen flow rate of 45 L / min. The coating process was carried out at 550 °C for 3 hours, resulting in a carbon-coated porous silicon-carbon anode material.
[0069] Comparative Example 1
[0070] Porous carbon matrix powder is placed in a conventional fluidized bed reactor equipped with a stirring paddle, and the powder naturally accumulates at the bottom of the chamber to form an initial powder bed.
[0071] Before starting, nitrogen gas is introduced into the cylinder to replace the air and create a protective atmosphere. The heating device is then activated to raise the temperature inside the cylinder to the reaction temperature of 540°C.
[0072] A mixture of silane and nitrogen at a flow rate of 20 L / min is introduced through the first air inlet pipe at the bottom of the cylinder as the reaction gas; at the same time, the bottom agitator disperses the powder bed at a speed of 70 rpm to maintain the fluidized state of the powder.
[0073] During the 5-hour deposition reaction, silane decomposes and deposits on the surface and inside the pores of the porous carbon matrix, ultimately yielding a porous silicon-carbon anode material with a carbon content of 48.2 wt%.
[0074] Carbon coating was applied to the deposited porous silicon-carbon material. A mixture of acetylene and nitrogen was used as the carbon source, with an acetylene flow rate of 5 L / min and a nitrogen flow rate of 45 L / min. The coating process was carried out at 550 °C for 3 hours, resulting in a carbon-coated porous silicon-carbon anode material.
[0075] Comparative Example 2
[0076] Porous carbon matrix powder is placed in an improved fluidized bed reactor equipped with only a second air inlet pipe, and the powder naturally accumulates at the bottom of the chamber to form an initial powder bed.
[0077] Before starting, nitrogen gas is introduced into the cylinder to replace the air and create a protective atmosphere. The heating device is then activated to raise the temperature inside the cylinder to the reaction temperature of 540°C.
[0078] A mixture of silane at a flow rate of 20 L / min and nitrogen at a flow rate of 100 L / min is introduced through the first air inlet pipe at the bottom of the cylinder as the reaction gas; at the same time, nitrogen at a flow rate of 100 L / min is introduced through four second air inlets evenly spaced along the side wall at the bottom to form an opposing jet to maintain the fluidization state of the powder.
[0079] During the 5-hour deposition reaction, silane decomposes and deposits on the surface and inside the pores of the porous carbon matrix, ultimately yielding a porous silicon-carbon anode material with a carbon content of 47.8 wt%.
[0080] Carbon coating was applied to the deposited porous silicon-carbon material. A mixture of acetylene and nitrogen was used as the carbon source, with an acetylene flow rate of 5 L / min and a nitrogen flow rate of 45 L / min. The coating process was carried out at 550 °C for 3 hours, resulting in a carbon-coated porous silicon-carbon anode material.
[0081] The final materials obtained from the above embodiments and comparative examples were tested.
[0082] The specific surface area of the material was determined by nitrogen adsorption.
[0083] The powder resistivity was tested using a pellet pressing method: 1 g of the prepared porous silicon-carbon composite powder was weighed and placed in a metal mold with a diameter of approximately 10 mm. The mold was then pressed into a disc with a thickness of approximately 2 mm using a press at 6 MPa. Copper electrodes were placed at both ends of the disc, ensuring good contact. The resistance value R at both ends was measured using a DC ohmmeter. Based on the disc thickness L and cross-sectional area A, the powder volume resistivity ρ = R × A / L was calculated.
[0084] Half-cell assembly: The prepared material is uniformly mixed with commercial graphite A at a mass ratio of 1:1 and used as the negative electrode material for lithium-ion batteries. The obtained negative electrode material is uniformly mixed with 2% carbon black, 2% sodium cellulate, and 3% styrene-butadiene rubber in an aqueous solvent to form a battery slurry. This slurry is then coated onto copper foil, dried, and cut into 8×8mm pieces. 2 After vacuum drying the lithium wafers at 110 degrees Celsius for 12 hours, half-cells were assembled on the lithium wafers in a glove box to evaluate their electrochemical performance.
[0085] Electrochemical testing: In the first week, discharge at 0.1C to 0.005V, then at 0.05C to 0.005V, and finally at 0.02C to 0.005V. After a 5-second rest period, charge at 0.1C to 1V (cutoff). Subsequent cycles consist of discharging at 0.5C to 0.005V, then at 0.2C to 0.005V, then at 0.05C to 0.005V, and finally at 0.02C to 0.005V, followed by a 5-second rest period and then charging at 0.5C to 1V (cutoff). The discharge capacity in the first week and the cycle life for 100 cycles were tested.
[0086] The discharge process in the electrochemical test of the above half-cell is a lithium insertion process, which corresponds to the charging process in the full cell, and the charging process is a lithium desorption process, which corresponds to the discharge process in the full cell.
[0087] Full charge expansion rate test: This is for the expansion of the electrode sheet. The calculation method is the ratio of the difference in electrode sheet thickness before and after full charge to the electrode sheet thickness before full charge. The electrode sheet thickness before full charge refers to the electrode sheet thickness when it is not charged.
[0088] The withstand voltage test is evaluated by detecting the electrochemical performance of the sample before and after pressure. The withstand voltage test conditions are: pressurize the sample with 50 MPa for 5 minutes, and then measure the tethering performance after pressure.
[0089] First-cycle efficiency after pressure treatment: Carbon-coated porous silicon-carbon composite powder treated with 50 MPa for 5 min was used to prepare electrode sheets according to the above half-cell assembly method. The first-cycle discharge capacity was recorded at 0.1C to 0.005V, 0.05C to 0.005V, and 0.02C to 0.005V. The first-cycle charge capacity was then recorded at 0.1C to 1V. The first-cycle charge capacity / first-cycle discharge capacity was used to obtain the first-cycle efficiency after pressure treatment.
[0090] Uniformity verification: The material was placed at a magnification of 1k+500 and EDS energy dispersive spectroscopy was performed to capture the overall elemental distribution; at the same magnification, backscattering test was performed to output the percentage of dark particles.
[0091] The test results are shown in Table 1 below:
[0092]
[0093] Table 1
[0094] As can be seen, Example 1 achieved the best overall effect.
[0095] A comparison of Example 1 (bottom-flush multi-directional jet + tangential turbulence) and Example 2 (conventional stirring + tangential turbulence) revealed that the fluidized bed reactor in Example 1 not only stably produced qualified materials, but also further optimized the proportion of dark particles to 0.75%, achieving better particle dispersion while eliminating the risk of mechanical failure.
[0096] As can be seen from the comparison between Example 2 and Comparative Example 1, the improved reactor structure introduces tangential turbulence (nitrogen 50L / min), which can disperse the material through airflow and reduce the proportion of dark particles to 0.82%.
[0097] Data analysis of Example 2 and Comparative Example 2 shows that the improvement in reactor structure to introduce tangential turbulence has a much more significant effect than the improvement in reactor structure to introduce counter-current jets. Although the use of counter-current jets in Comparative Example 2 can suppress the agglomeration of porous carbon matrix to some extent compared to Comparative Example 1, resulting in a reduction in the proportion of dark particles in the material, Example 2 shows a significantly greater reduction in the proportion of dark particles in the material compared to Comparative Example 2, and also improves parameters such as cycle life and full charge expansion rate.
[0098] The fluidized bed reactor for improving the uniformity of silicon-carbon anodes provided in this embodiment injects tangential turbulent airflow into the 60%–90% region of the bed height using a tangential turbulence generator. This effectively increases the turbulence in the upper part of the bed and thoroughly breaks up top agglomerates, thereby improving particle dispersion. Furthermore, in a preferred embodiment, multiple second air inlets evenly distributed circumferentially along the bottom of the fluidized bed reactor cylinder provide multi-directional counter-current airflow at the bottom. This further generates high-intensity shear vortices, achieving in-situ particle dispersion, replacing mechanical stirring, and effectively avoiding the problem of mechanical jamming of the stirring blades. Multiple uniformly distributed air holes on the pipe wall at the outlet end of the first air inlet provide lateral blowing airflow at the bottom, preventing the formation of local dead zones and ensuring sufficient gas-solid contact. Through the synergistic effect of the above-mentioned multi-flow fields, the entire flow pattern of the bed is reconstructed. In the preparation of silicon-carbon anodes, the deposition uniformity of silicon in porous carbon particles can be improved to over 99%, achieving continuous and stable production of silicon-carbon anode materials.
[0099] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A fluidized bed reactor for improving the uniformity of silicon-carbon anodes, characterized in that, The fluidized bed reactor includes: A fluidized bed reactor shell includes a feed inlet and a discharge outlet; the feed inlet is located on the top or side wall of the fluidized bed reactor shell; the discharge outlet is located at the bottom of the fluidized bed reactor shell. The chassis is detachably mounted on the feed inlet of the fluidized bed reactor cylinder; The first air inlet pipe is installed on the chassis, and the air outlet of the first air inlet pipe is located inside the fluidized bed reactor cylinder. A tangential turbulence generator is installed on the upper side wall of the fluidized bed reactor cylinder. The outlet direction of the nozzle of the tangential turbulence generator is inclined upward relative to the radial plane of the fluidized bed reactor cylinder and is tangentially set at 15°-75° with the side wall. Tangential airflow is injected in the region of 60%-90% of the bed height.
2. The fluidized bed reactor according to claim 1, characterized in that, The tangential turbulence generators are multiple and are evenly distributed around the perimeter of the fluidized bed reactor cylinder.
3. The fluidized bed reactor according to claim 2, characterized in that, There are three tangential turbulence generators.
4. The fluidized bed reactor according to claim 1, characterized in that, Multiple air holes are evenly distributed on the wall of the outlet end of the first air inlet pipe, and airflow is ejected from the air holes that penetrates laterally from the center of the chassis to the side wall of the cylinder.
5. The fluidized bed reactor according to claim 4, characterized in that, The fluidized bed reactor further includes a rotating device, which comprises: The drive unit is located below the chassis and is connected to the lower end of the first air intake pipe via a connecting part; The control unit is connected to and drives the drive unit to rotate, thereby causing the first air intake pipe or the air outlet of the first air intake pipe to rotate.
6. The fluidized bed reactor according to claim 1, characterized in that, The fluidized bed reactor also includes multiple second air inlet pipes; Multiple second air inlet pipes are evenly distributed circumferentially along the bottom of the fluidized bed reactor cylinder; The outlet of each second air inlet pipe is inclined downwards at 15°-75° toward the bottom of the fluidized bed reactor cylinder, and the airflow ejected from the outlet forms a multi-directional jet that counteracts each other at the bottom of the fluidized bed reactor.
7. The fluidized bed reactor according to claim 6, characterized in that, There are 3-8 second air intake pipes.
8. The fluidized bed reactor according to claim 1, characterized in that, The fluidized bed reactor also includes a stirring paddle; the stirring paddle is located at the bottom of the fluidized bed reactor cylinder.
9. The fluidized bed reactor according to claim 1, characterized in that, The fluidized bed reactor also includes a heating device; the heating device is disposed outside the fluidized bed reactor cylinder and is attached to the outer wall of the fluidized bed reactor cylinder.
10. The fluidized bed reactor according to claim 1, characterized in that, The chassis can be opened and closed by a snap-on mechanical switch or by a cylinder. The chassis opens from the discharge port to discharge material into the fluidized bed reactor cylinder, or the chassis closes to the discharge port to seal the bottom of the fluidized bed reactor cylinder.