Horizontal vibrating fluidized bed coating device

Abstract

The utility model discloses a horizontal vibration fluidized bed formula coating device, including base and cylinder, the inside cylinder includes preheating section, coating section, solidification section and discharge section along the axial direction in proper order, and the fluidization gas chamber is communicated below the composite gas distribution board, and polymer introduction subassembly is used for evaporating polymer into steam and evenly permeating distribution in coating section, and the temperature required for the partition temperature control unit is used for independently regulating and controlling preheating section, coating section and solidification section. The utility model solves the existing coating device and has the problems such as poor fluidization uniformity, easy to produce ditch flow, elutriation and uneven steam distribution to make the coating too thick or leak bag, through the combination of vibration, composite gas distribution board and polymer introduction subassembly, can effectively inhibit the ditch flow, elutriation problem that micron silicon carbon particles easily appear in traditional fluidized bed, maintain the stability of fluidization, ensure that polymer steam and silicon carbon particles are fully, evenly contacted, realize the uniform coating of nanometer thickness and the deviation is extremely small.

Description

Technical Field

[0001] This utility model relates to the technical field of lithium battery material preparation equipment, specifically to a horizontal vibrating fluidized bed coating device. Background Technology

[0002] Silicon-carbon composite materials, used as high-capacity lithium-ion battery anodes, combine the high specific capacity of silicon (theoretically 4200 mAh / g) with the stability of carbon, potentially breaking through the theoretical limits of traditional graphite anodes. However, silicon experiences volume expansion exceeding 300% during charge and discharge, leading to particle pulverization and continuous SEI film growth, severely limiting cycle life. To overcome this defect, polymer-derived carbon coating technology has been widely adopted: polymer precursors such as PMMA (polymethyl methacrylate) are uniformly coated onto the surface of silicon-carbon particles, which are then pyrolyzed to form a tough, highly conductive carbon layer, effectively buffering volume changes and stabilizing the electrode interface.

[0003] Current industrial coating processes face three main bottlenecks: poor fluidization uniformity, due to the small particle size of silicon-carbon particles (D50 mostly 1-20μm), which easily leads to channeling and segregation in traditional vertical fluidized beds, with a fine powder entrainment rate >15%, resulting in raw material loss and dust safety hazards; uneven coating layer, with solvent residues (>500ppm) in impregnation or spray coating methods affecting battery performance; and uneven polymer vapor distribution in vapor-phase coating, resulting in excessively thick local coatings (>200nm) or gaps, causing local stress concentration during charging and discharging. Therefore, there is an urgent need to develop a dedicated device that combines fluidization stability and coating uniformity to meet the requirements of high-performance continuous production of silicon-carbon anode materials. Utility Model Content

[0004] The technical problem to be solved by this utility model is that existing coating devices have poor fluidization uniformity, which easily leads to channeling, separation and uneven steam distribution, resulting in excessive coating or leakage. The purpose is to provide a horizontal vibrating fluidized bed coating device.

[0005] This utility model is achieved through the following technical solution: A horizontal vibrating fluidized bed coating device includes: Base The cylinder body includes, in sequence along the axial direction, a preheating section, a coating section, a curing section, and a discharge section. The preheating section is connected to a feeding hopper, and the discharge section is connected to a discharge pipe. A composite gas distribution plate is also provided at the bottom of the cylinder body. A fluidizing gas chamber is connected below the composite gas distribution plate, and a gas source unit is connected to the fluidizing gas chamber. A polymer introduction component is used to evaporate the polymer into vapor and distribute it evenly throughout the coating section; The vibration unit, located inside the base, is used to drive the cylinder to vibrate in order to assist fluidization; The zoned temperature control unit is used to independently regulate the required temperatures of the preheating section, coating section, and curing section.

[0006] As one of the preferred technical solutions, the polymer introduction assembly includes a polymer evaporator, a steam injection pipe and a metal diffuser connected in sequence. The polymer evaporator is located outside the coating section, the steam injection pipe is obliquely arranged on the cylinder and its outlet end extends into the coating section, and the metal diffuser is located at the end of the steam injection pipe.

[0007] As one of the preferred technical solutions, a spiral guide vane is provided inside the steam injection pipe, and the porosity of the metal diffuser head is 40%-60%.

[0008] As one of the preferred technical solutions, the vibration unit includes multiple symmetrically arranged vibration motors, and the bottom of the base is provided with a spring support.

[0009] As one of the preferred technical solutions, the partitioned temperature control unit includes independent heating jackets respectively fitted on the outer walls of the preheating section, coating section and curing section, and each independent heating jacket is equipped with an armored thermocouple.

[0010] As one of the preferred technical solutions, the composite gas distribution plate includes a double-layer sintered metal plate, with a quartz sand layer filling the space between the double-layer sintered metal plates. The quartz sand particles have a bimodal particle size distribution, with one type of particle having a particle size of 0.6-0.8 mm and the other type having a particle size of 0.3-0.4 mm. The mass ratio of the two types of particles is (60-70):(30-40). The porosity of the distribution plate is 30%-50%, and the pore size is 50-200 μm.

[0011] As one of the preferred technical solutions, the outer wall of the discharge pipe is covered with a cooling jacket.

[0012] As one of the preferred technical solutions, the inner wall of the cylinder is covered with an alumina ceramic layer, the thickness of which is 0.2-0.5 mm and the surface roughness Ra≤0.1μm; an antistatic ion bar is installed on the top of the cylinder.

[0013] As one of the preferred technical solutions, a multi-stage cyclone separator is connected to the top of the cylinder near the discharge section.

[0014] As one of the preferred technical solutions, explosion relief discs are provided at the top of the discharge section and in the fluidizing gas chamber.

[0015] Compared with the prior art, this utility model has the following advantages and beneficial effects: 1. The horizontal vibrating fluidized bed coating device provided in this embodiment of the invention adopts a horizontal cylindrical body and is divided into preheating, coating, curing, and discharging functional sections. By combining vibration-assisted fluidization with a composite gas distribution plate, the channeling and segregation problems that easily occur in micron-sized silicon-carbon particles in traditional fluidized beds can be effectively suppressed, maintaining the stability of fluidization; the polymer introduction component ensures full and uniform contact between polymer vapor and silicon-carbon particles, achieving uniform coating with nanometer-level thickness and minimal deviation.

[0016] 2. The horizontal vibrating fluidized bed coating device provided in this embodiment of the utility model has a vibration frequency provided by the vibration unit that is not only used to assist fluidization, but its specific amplitude (0.5-3mm) is designed to break the polymer condensate film without destroying the intact coating layer, thereby achieving molecular-level spreading and homogenization. At the same time, the vibration energy is coupled with the kinetic energy of the polymer introduction component and cooperates with the zoned temperature control unit to ensure the penetration depth and distribution uniformity of polymer vapor in the bed. The linkage control of the three ensures the uniform coating and consistency of the product. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model; Figure 2 This is a cross-sectional view showing the connection between the cylindrical body and the base of this utility model; Figure 3 This is a side sectional view of the cylindrical body of this utility model.

[0018] The attached diagram shows the markings and corresponding component names: 1-Feeding hopper; 2-Cylinder; 201-Preheating section; 202-Coating section; 203-Curing section; 204-Discharge section; 3-Vibration motor; 4-Spring support; 5-Gas source; 6-Mass flow meter; 7-Hot air furnace; 8-Fluorescent gas chamber; 9-Polymer evaporator; 10-Steam jet pipe; 11-Metal diffuser head; 12-Composite gas distribution plate; 13-Alumina ceramic layer; 14-Independent heating jacket; 15-Sheathed thermocouple; 16-Antistatic ion bar; 17-Explosion relief diaphragm; 18-Differential pressure sensor; 19-Cooling jacket; 20-Discharge pipe; 21-Multi-stage cyclone separator; 22-Base. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0020] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] In the description of this utility model, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this utility model.

[0022] Example 1

[0023] This embodiment 1 provides a horizontal vibrating fluidized bed coating device for uniformly coating polymer precursors onto the surface of silicon-carbon particles, such as... Figure 1 and Figure 2 As shown, the device includes a base 22 and a cylindrical body 2. The cylindrical body 2 is positioned above the base 22, which supports and fixes it. The cylindrical body 2 is a horizontal cylindrical structure. Inside the cylindrical body 2, along the axial direction, it sequentially includes a preheating section 201, a coating section 202, a curing section 203, and a discharge section 204. The preheating section 201 is connected to a feeding hopper 1, allowing silicon carbide particles to enter from the feeding hopper 1 at a certain rate and then continuously enter the preheating section 201 via a loss-in-weight feeder. The discharge section 204 is connected to a discharge pipe 20, through which the coated silicon carbide particles are discharged.

[0024] A composite gas distribution plate 12 is also provided at the bottom of the cylinder 2. A fluidizing gas chamber 8 is connected below the composite gas distribution plate 12. In this process, a receiving cavity is provided inside the base 22, and the fluidizing gas chamber 8 is located in the receiving cavity and connected to the cylinder 2.

[0025] The fluidizing chamber 8 is connected to the gas source section 5. The gas source section 5 provides the required cleaning gas, wherein the cleaning gas or fluidizing gas is one or a mixture of nitrogen, argon, and helium, preferably nitrogen. Before fluidization, the cleaning gas purges the cylinder 2 to reduce the oxygen content inside the cylinder 2 and protect the equipment and materials.

[0026] In addition, the gas source unit 5 provides fluidizing gas. A mass flow meter and a hot air furnace 7 are provided between the gas source unit 5 and the fluidizing gas chamber 8. The total flow rate of the fluidizing gas is monitored and controlled by the mass flow meter 6. After the fluidizing gas is preheated to a specific temperature by the hot air furnace 7, it can be ensured that the fluidizing gas enters the fluidizing gas chamber 8. The preheated fluidizing gas is used to preheat silicon carbide particles and establish a fluidized state.

[0027] It is understood that the function of the composite gas distribution plate 12 is to provide uniform, stable, and anti-clogging gas distribution. Specifically, the composite gas distribution plate 12 includes a double-layer sintered metal plate, with a quartz sand layer filling the space between the two layers.

[0028] The quartz sand layer exhibits a bimodal particle size distribution, with one type of particle having a diameter of 0.6-0.8 mm and the other type having a diameter of 0.3-0.4 mm. The mass ratio of the two types of particles is (60-70):(30-40). The porosity of the distribution plate is 30%-50%, with pore sizes ranging from 50-200 μm. The quartz sand layer is designed with a bimodal particle size distribution (i.e., the sand layer is composed of two different particle size ranges of quartz sand mixed in a specific ratio). The core principle is to ensure airflow and prevent fine powder blockage through the synergistic filling of coarse and fine particles.

[0029] That is, after fine particles fill the gaps between coarse particles, the minimum pore size of the sand layer is determined by the fine particles, which can effectively prevent fine powder (such as powder with a particle size > 0.1 mm) in the material layer from penetrating into the interior of the sand layer, and prevent fine powder from clogging the pores of the sintering plate or entering the air chamber; the main skeleton constructed by coarse particles ensures that the overall air permeability resistance of the sand layer is not too high, and even if fine particles fill part of the gaps, the main pore channels can still ensure smooth airflow.

[0030] Furthermore, differential pressure sensors 18 are installed above and below the composite porous baffle. Specifically, the differential pressure sensors 18 indirectly reflect the flow state of the fluidizing gas by detecting the pressure difference between two pressure points. That is, if the pressure difference is too low, it indicates that the gas velocity is insufficient, and the powder is prone to deposition; if the pressure difference is too high, it indicates that the gas velocity is too high, and energy consumption increases. The gas supply to the fluidizing chamber 8 is adjusted based on the feedback of the pressure difference. Once the pressure stabilizes, the next step of operation can be performed.

[0031] Furthermore, a polymer introduction component is provided in the coating section 202. The function of the polymer introduction component is to evaporate the polymer into vapor and distribute it evenly in the coating section 202.

[0032] Additionally, a vibration unit is positioned below the cylinder 2 (located inside the base 22) to drive the cylinder 2 to vibrate and assist in fluidization. During vibration, the vibration unit drives the base 22 to vibrate and transmits the vibration to the cylinder 2. Furthermore, in this embodiment, the vibration unit is kinetically coupled with the polymer introduction component, thereby improving the penetration depth and distribution uniformity of steam in the bed.

[0033] It also includes a zoned temperature control unit for independently regulating the required temperatures of the preheating section 201, coating section 202, and curing section 203. Specifically, the zoned temperature control unit includes independent heating jackets 14 respectively fitted onto the outer walls of the preheating section 201, coating section 202, and curing section 203, and each independent heating jacket 14 is equipped with an armored thermocouple 15.

[0034] The achievable effects are as follows: the independent heating jacket 14 can be set with its own heating rate and holding time for each section, without having to accommodate the temperature requirements of other sections. This achieves precise and controllable temperature for each section, monitorable deviations, and the ability to block interference, ensuring that each process step is carried out at the optimal temperature. It also further prevents the adhesion of silicon-carbon particles.

[0035] Furthermore, the outer wall of the discharge pipe 20 is covered with a cooling jacket 19. The cooling jacket 19 allows the discharged particles to be cooled rapidly, ensuring stability and safety in the discharge process.

[0036] Differential pressure sensors 18 are installed above and below the composite porous baffle. The composite porous baffle ensures the uniformity of the fluidizing gas, and the quartz sand layer prevents fine particles from clogging the pores. The differential pressure sensors 18 detect the fluidization state, and proceed to the next step after the displayed stable pressure is reached.

[0037] Furthermore, a multi-stage cyclone separator 21 is connected to the top of the cylinder 2 near the discharge section 204. This separator can capture ultrafine particles (dust) carried out by the airflow, achieving material recovery and gas purification.

[0038] In addition, the top of the discharge section 204 and the fluidizing gas chamber 8 are both equipped with explosion relief discs 17 for overpressure protection.

[0039] The specific working process of this embodiment is as follows: First, the cylinder 2 is cleaned with cleaning gas. Then, heated fluidizing gas is introduced and the vibration unit is started. Silicon carbon particles enter from the preheating section 201 and form a fluidized state. Due to continuous feeding, the silicon carbon particles are pushed to the coating section 202 in the vibrating fluidized state. The polymer introduction component condenses, wets and spreads the polymer vapor on the lower temperature particle surface to form a film.

[0040] The coated particles enter the curing section 203 with fluidization, where the polymer molecular chains are further extended and initially cross-linked at a specific temperature, enhancing adhesion and uniformity.

[0041] The coated granules are discharged through the discharge pipe 20 of the discharge section 204, and are rapidly cooled to below 60°C by the external water-cooling jacket. Then, they are sent to the downstream tubular pyrolysis furnace through a sealed conveying system (for carbonization treatment at 850°C and under N2 atmosphere for 1 hour), thus realizing continuous production.

[0042] Example 2

[0043] To ensure sufficient and uniform contact between the polymer vapor and the silicon-carbon particles, this embodiment also includes a polymer introduction component. It is understood that, as... Figure 1 and Figure 3 As shown, multiple polymer introduction components are provided, and the multiple polymer introduction components are evenly arranged on the lower side of the coating section 202. There can be 2-6 polymer introduction components.

[0044] Each polymer primer assembly includes a polymer evaporator 9, a vapor jet pipe 10, and a metal diffuser head 11 connected in sequence. The polymer evaporator 9 is located outside the coating section 202. The vapor jet pipe 10 is obliquely arranged on the cylinder 2 with its outlet end extending into the coating section 202. The metal diffuser head 11 is located at the end of the vapor jet pipe 10. The function of the metal diffuser head 11 is to efficiently and uniformly disperse the gas (or vapor) into microbubbles or gas flow. Simultaneously, its structural characteristics enable it to resist clogging, resist corrosion, and stabilize mass transfer, providing crucial gas distribution functionality for gas-liquid contact.

[0045] The specific process is as follows: the external polymer evaporator 9 is started to evaporate the polymer, and the evaporated polymer is evenly injected into the fluidized bed through the steam injection pipe 10 and the metal diffuser head.

[0046] Specifically, the inclination angle α (in °) of the steam injection pipe 10 satisfies the following relationship with the diameter D (in m) of the cylinder 2 and the average particle size dp (in μm): α = k * (D / dp)^0.5, where k is a correction coefficient with a value ranging from 15 to 25. Additionally, a spiral guide vane is installed inside the steam injection pipe 10, and the porosity of the metal diffuser head 11 is 40%-60%. Verification has shown that this relationship and structure ensure optimal coating effect of polymer steam on particles of different sizes in devices of varying scales.

[0047] Example 3

[0048] In existing industrial coating processes, silicon-carbon particles tend to stick to the walls and agglomerate. The adhesion properties of polymer melts cause particles to accumulate on the inner walls of the equipment. In particular, the stagnation zone of horizontal fluidized beds is more prone to agglomeration, requiring frequent shutdowns for cleaning, and the continuous operating time is less than 48 hours.

[0049] Based on the above problems, this embodiment is configured as follows: the inner wall of the cylinder 2 is covered with an alumina ceramic layer 13, the thickness of the alumina ceramic layer 13 is 0.2-0.5 mm, and the surface roughness Ra≤0.1μm; an antistatic ion rod 16 is installed on the top of the cylinder 2.

[0050] The antistatic ion bar 16 neutralizes the static charge on the particle surface, ensuring the material remains loose and uniform. The alumina ceramic layer 13 directly withstands the impact and friction of the material, preventing the cylinder 2 from being worn through or pits from appearing on the inner wall, with a wear resistance life > 10,000 hours. After polishing, the alumina ceramic layer 13 has an extremely low surface roughness, making it difficult for material to adhere to the wall surface, thus reducing material waste or process interference caused by wall clumping.

[0051] Example 4

[0052] Based on Embodiment 1, the vibration unit in this embodiment includes multiple symmetrically arranged high-frequency vibration motors 3, and a spring support 4 is provided at the bottom of the base 22. Two to four vibration motors 3 can be symmetrically arranged. The operating parameters of the vibration motors 3 are an amplitude of 0.5-3 mm, a frequency of 20-100 Hz, and a vibration direction perpendicular to the axis of the cylinder 2. The vibration frequency is not only used to assist fluidization, but its specific amplitude (0.5-3 mm) is designed to just break the polymer condensate film without damaging the intact coated layer, thereby achieving molecular-level spreading and homogenization. Simultaneously, this vibration energy is coupled with the kinetic energy of the tilted jet steam, ensuring the penetration depth and distribution uniformity of the steam in the bed, effectively improving the uniformity and consistency of the coated product.

[0053] In this embodiment, the vibration motor 3 is located inside the receiving cavity, and the bottom of the base 22 is supported by a spring support 4 to avoid stress concentration caused by rigid connection. The vibration motor 3 and the spring support 4 work together to generate vibration on the base 22, and the base 22 supports the cylinder 2 and transmits the vibration.

[0054] The horizontal vibrating fluidized bed device of this invention, taking polymer PMMA (polymethyl methacrylate) as an example, specifically realizes the working process of PMMA-coated silicon-carbon anode as follows: Silicon-carbon composite particles with an average particle size (D50) of 8.0 μm were coated. During operation, high-purity nitrogen was first introduced to replace the air. Then, the temperatures of the preheating section 201, coating section 202, and curing section 203 were set to 85℃, 88℃, and 98℃, respectively. After the temperature stabilized, the bottom vibration motor 3 (frequency 50Hz, amplitude 1.5mm) was turned on, and 90℃ nitrogen gas (heated by the hot air furnace 7) was introduced as the fluidizing gas (gas velocity 0.3m / s). Silicon-carbon particles were added from the feed inlet at a rate of 50 kg / h. After the PMMA powder was vaporized in the polymer evaporator 9 (250°C), it was injected into the coating section 202 by a nitrogen flow of 30 Nm³ / h through multiple 45° inclined steam jet pipes 9. The particles remained in the container for an average of 40 minutes and were finally discharged through the outlet.

[0055] 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 horizontal vibrating fluidized bed coating device, characterized in that, include: Base The cylinder body includes, in sequence along the axial direction, a preheating section, a coating section, a curing section, and a discharge section. The preheating section is connected to a feeding hopper, and the discharge section is connected to a discharge pipe. A composite gas distribution plate is also provided at the bottom of the cylinder body. A fluidizing gas chamber is connected below the composite gas distribution plate, and a gas source unit is connected to the fluidizing gas chamber. A polymer introduction component is used to evaporate the polymer into vapor and distribute it evenly throughout the coating section; The vibration unit, located inside the base, is used to drive the cylinder to vibrate in order to assist fluidization; The zoned temperature control unit is used to independently regulate the required temperatures of the preheating section, coating section, and curing section.

2. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, The polymer introduction assembly includes a polymer evaporator, a steam injection pipe, and a metal diffuser connected in sequence. The polymer evaporator is located outside the coating section, the steam injection pipe is obliquely arranged on the cylinder and its outlet end extends into the coating section, and the metal diffuser is located at the end of the steam injection pipe.

3. The horizontal vibrating fluidized bed coating device according to claim 2, characterized in that, The steam injection pipe is equipped with a spiral guide vane, and the porosity of the metal diffuser head is 40%-60%.

4. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, The vibration unit includes multiple symmetrically arranged vibration motors, and the base is provided with a spring support at the bottom.

5. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, The zoned temperature control unit includes independent heating jackets respectively fitted on the outer walls of the preheating section, coating section and curing section, and each independent heating jacket is equipped with an armored thermocouple.

6. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, The composite gas distribution plate comprises a double-layer sintered metal plate, with a quartz sand layer filling the space between the two layers. The quartz sand particles have a bimodal particle size distribution, with one type of particle having a size of 0.6-0.8 mm and the other type having a size of 0.3-0.4 mm. The mass ratio of the two types of particles is (60-70):(30-40). The distribution plate has an open area of ​​30%-50% and a pore size of 50-200 μm.

7. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, The outer wall of the discharge pipe is covered with a cooling jacket.

8. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, The inner wall of the cylinder is covered with an alumina ceramic layer with a thickness of 0.2-0.5 mm and a surface roughness Ra≤0.1μm; an antistatic ion bar is installed on the top of the cylinder.

9. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, A multi-stage cyclone separator is connected to the top of the cylinder near the discharge section.

10. The horizontal vibrating fluidized bed coating device according to claim 1, characterized in that, Both the top of the discharge section and the fluidizing gas chamber are equipped with explosion relief discs.

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