Wide gas phase dispersion powder electrostatic deposition device and use method thereof

Abstract

The invention provides a wide-width gas-phase dispersion powder electrostatic deposition device and a using method thereof.The device comprises a reciprocating type guiding discharging module used for evenly supplying and preliminarily distributing powder in the width direction, and the reciprocating type guiding discharging module comprises a powder conveying pipe reciprocating in the width direction and a vibration comb arranged at the discharging end of the powder conveying pipe; the powder dispersing module is located below the discharging port of the distribution hopper and used for conducting electrostatic dispersion on powder and accelerating falling of the powder, and the powder dispersing module comprises a first rotating pin wheel set, a second rotating pin wheel set and a laminar flow gas nozzle which are sequentially arranged in the falling direction of the powder; the method overcomes the defects that in an existing continuous preparation technology, powder cannot be effectively dispersed in the belt walking width direction, the electrode preparation amplitude width is limited by the spray gun width, and the thickness uniformity of a wide diaphragm in the width direction is poor due to multiple spray guns, and the like, and the energy storage device production technology level is comprehensively improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage device fabrication technology, and more particularly to a wide-range gas-phase dispersed powder electrostatic deposition device and its usage method. Background Technology

[0002] In the fabrication of energy storage devices, the manufacturing of functional layers such as electrodes and solid electrolytes is moving towards solvent-free processes. Solvent-free powder layer preparation technology abandons traditional slurry coating processes, avoiding the use and recycling of large amounts of organic solvents. It offers significant advantages such as being environmentally friendly, having low energy consumption, a high proportion of active materials, avoiding side reactions between binders and active materials in solvents, and preventing stratification of components with different densities during solvent evaporation. Its core objective is to uniformly and densely lay micron- or submicron-sized active material particles, conductive agents, and binders on the surface of a metal current collector or support membrane, forming a powder layer with a specific thickness, uniform composition, and good consistency, which is then cured into a film through subsequent hot pressing and other processes.

[0003] Dispersing and assisted spreading of powder using turbulent airflow is currently the main method for preparing solvent-free powder layers. However, this method, due to the high-pressure, high-speed turbulence, generates frequent powder collisions. For viscous powders or core-shell structured powders with added binders in electrode preparation, this can easily lead to electrostatic accumulation and multi-particle aggregation and adhesion, resulting in uneven powder layer composition. Furthermore, the powder is prone to accumulating in the transfer pipeline, forming deposition mounds that affect the uniformity of powder dispersion. When the uneven powder layer is formed through subsequent roll forming processes, local defects caused by uneven stress due to hard cores and voids in the powder layer can affect the film's functionality. In the process of preparing battery electrodes, electrolyte films, or supercapacitor electrodes with excellent mechanical strength and electrochemical performance, how to uniformly disperse viscous powder particles coated with binders onto a wide-width conveyor belt surface has always been a key breakthrough direction in this field. Summary of the Invention

[0004] To address the technical problems of uneven powder dispersion, limited deposition width, poor thickness consistency, and difficulty in effectively removing large particle agglomerates in existing continuous dry electrode preparation technologies, this invention provides a wide-width gas-phase dispersed powder electrostatic deposition device and its usage method. This invention primarily utilizes a vibrating comb to guide the powder uniformly into a wide-width distribution hopper, combined with two sets of rotating pinwheels with progressively increasing linear velocities for quantitative wide-width discharge. Through the synergistic effect of online sieving using a V-shaped vibrating screen and an electrostatic confinement device, it achieves uniform, stable, and highly consistent electrostatic dispersion and deposition of micron-sized powder on a wide-width conveyor film, while simultaneously removing unqualified large particles, thus comprehensively improving the quality and production efficiency of the solvent-free powder deposition layer.

[0005] The technical means employed in this invention are as follows:

[0006] A wide-area gas-phase dispersed powder electrostatic deposition device, comprising: A reciprocating guide discharge module is used to uniformly supply and initially distribute powder along the width direction. The reciprocating guide discharge module includes a powder conveying pipe that reciprocates along the width direction and a vibrating comb set at the discharge end of the powder conveying pipe. The powder distribution module, located below the vibrating comb, is used to receive and buffer the powder output from the reciprocating guide discharge module. The powder distribution module includes a distribution hopper extending in the width direction. The powder dispersion module is located below the discharge port of the distribution hopper. It is used to electrostatically disperse the powder and accelerate the powder falling. The powder dispersion module includes a first rotating needle wheel group, a second rotating needle wheel group, and a laminar air nozzle arranged sequentially along the powder falling direction. The screening and recovery module, located below the powder dispersion module, is used to screen the falling powder. The screening and recovery module includes a V-shaped screen device. The powder deposition and confinement module includes a conveyor assembly for carrying and transporting the conveyor base film, and electrostatic confinement devices symmetrically arranged below the screening and recovery module and distributed along the width direction to confine the falling path of the powder.

[0007] Furthermore, the reciprocating guide discharge module, powder distribution module, powder dispersion module, screening and recovery module, and powder deposition and constraint module are disposed within the external frame; A crossbar is provided in the upper part of the interior of the outer frame; the crossbar is provided in the width direction, a reciprocating slide rail is provided on the crossbar, a reciprocating driver is provided on the reciprocating slide rail, a powder conveying pipe is fixed to the reciprocating driver in the vertical direction, and a vibrating comb is fixed to the lower end of the powder conveying pipe. An internal frame is provided below the crossbar, and a perforated inner wall box is provided inside the internal frame. The perforated inner wall box has an opening at the top and a distribution hopper is provided at the opening along the width direction. The lower part of the vibrating comb extends into the distribution hopper. The porous inner wall box at the bottom of the distribution hopper is provided with a first rotating pinwheel group, a second rotating pinwheel group, a laminar air nozzle and a V-shaped screen device in sequence from top to bottom; The lower part of the internal frame is provided with a conveyor belt base film that is transported from front to back.

[0008] Furthermore, the first rotating pinwheel assembly, the second rotating pinwheel assembly, the laminar flow nozzle, and the V-shaped screen device are arranged along the width direction; The first rotating needle wheel assembly includes two relatively rotating first rotating needle wheels arranged in a front-to-back manner, and the first rotating needle wheel assembly is located at the outlet of the dispensing hopper; The second rotating needle wheel assembly includes two relatively rotating second rotating needle wheels arranged in a front-to-back manner, and the first rotating needle wheel assembly and the second rotating needle wheel assembly are electrically connected to the needle wheel driver; The laminar flow nozzle extends into the porous inner wall box from the laminar flow air inlet and is inclined downwards. The end of the laminar flow nozzle is located below the second rotating needle wheel assembly.

[0009] Furthermore, the needle length of the first rotating needle wheel is equal to the minimum surface distance between the two first rotating needle wheels; the needle length of the second rotating needle wheel is equal to the minimum surface distance between the second rotating needle wheel and its nearest first rotating needle wheel; the needle length of the second rotating needle wheel is greater than the needle length of the first rotating needle wheel, and the rotational linear velocity of the second rotating needle wheel group is greater than the rotational linear velocity of the first rotating needle wheel group.

[0010] Furthermore, the laminar gas nozzle includes a laminar gas electrostatic electrode and a laminar gas electrostatic electrode line disposed inside the housing, wherein the laminar gas electrostatic electrode is connected to the laminar gas electrostatic electrode line.

[0011] Furthermore, the reciprocating drive includes a reciprocating drive block and a reciprocating drive wheel connected together. The reciprocating drive wheel moves horizontally on a reciprocating slide rail, and the reciprocating drive block fixes the powder conveying pipe.

[0012] Furthermore, the upper chamber air inlet, laminar flow air inlet and lower chamber air inlet are symmetrically arranged on the front and rear side walls of the internal frame from top to bottom, and the chamber temperature control pipe is installed inside the porous inner wall chamber.

[0013] Furthermore, a base film support plate and a support frame are sequentially arranged below the base film, and a heating device is installed inside the base film support plate.

[0014] Furthermore, a set of insulating support blocks is provided at the front and rear bottom of the porous inner wall box. The insulating support blocks support the high-voltage linear electrodes distributed along the deposition width direction. The high-voltage linear electrodes are connected to the high-voltage power supply line.

[0015] The present invention also provides a method for using a wide-width vapor-phase dispersed powder electrostatic deposition apparatus, which is based on any of the above-mentioned wide-width vapor-phase dispersed powder electrostatic deposition apparatuses, and includes the following steps: S1. Lay the base film and start the conveyor belt. Set and start the heating device of the base film support plate so that the surface temperature of the base film reaches and stabilizes at the first set temperature. S2. Set and activate the chamber temperature control tube in the porous inner wall chamber so that the temperature inside the chamber reaches and stabilizes at the second set temperature. S3. The dried deposited powder is conveyed through the powder conveying pipe, and the driver of the vibrating comb is started to make the powder flow out at a uniform rate. S4. Start the reciprocating drive to drive the powder conveying pipe to reciprocate along the width of the crossbar, so that the powder falls into the distribution hopper to form a powder layer; after the powder layer is stable, start the air supply system of the porous inner wall box, the pinwheel drive of the first and second rotating pinwheel groups, the air supply and power supply system of the laminar air nozzle, and the V-shaped screen device in sequence. S5. Adjust the rotational linear speed of the first rotating pinwheel group to keep the powder layer depth in the distribution hopper constant; adjust the rotational linear speed of the second rotating pinwheel group to 1 to 10 times the linear speed of the first rotating pinwheel group; adjust the laminar gas ionization voltage of the laminar gas nozzle to 15-80kV, and adjust the airflow size to make the powder stream fall stably; adjust the vibration parameters of the V-shaped screen device. S6. Qualified powder particles sieved by the V-shaped screen device fall and, under the electric field constraint generated by the 15-80kV linear confinement electrodes with the same charge, are deposited on the surface of the conveyor belt substrate to form a powder layer. Large powder particles that are sieved out are recovered by the V-shaped screen device. Compared with the prior art, the present invention has the following advantages: The present invention uses a vibrating comb located at the outlet of the powder conveying pipe, which can avoid the periodic accumulation of powder in the powder conveying pipe caused by using a reciprocating discharge end, and the discharge speed is not affected by the reciprocating distance.

[0016] The present invention employs a distribution hopper and two sets of rotating pinwheels for wide-width, constant-speed discharge, which can significantly reduce the problem of uneven local pressure of powder caused by the reciprocating spreading mode. The vibrating comb of the powder conveying pipe extends deep into the distribution hopper to level the powder in the hopper, avoiding uneven feeding of the substrate in the width direction caused by uneven powder pressure in the hopper.

[0017] This invention employs a temperature-controlled porous inner wall chamber to heat or cool the internal and external environments of the chamber. This can dynamically dry the powder by heating or cooling to reduce the viscosity of the powder binder, thereby improving the electrostatic dispersion efficiency of the powder. It can also avoid the agglomeration of the powder layer due to viscosity or water absorption capillary effect by changing the input gas source to dry air, nitrogen, argon, etc., which is more conducive to the electrostatic dispersion of the powder. A second rotating pinwheel assembly is used to clean the first rotating pinwheel, ensuring that there is no residue on the surface of the first rotating pinwheel and accelerating the full mixing of the powder and hot gas.

[0018] This invention uses a V-shaped vibrating screen installed at the powder discharge end for dynamic screening. The powder slides to a position suitable for continuous production and continuously recovers large particles without affecting the uniformity of the powder distribution.

[0019] This invention uses a linear high-voltage electrode in the width direction to constrain the falling powder, further reducing the fluctuation of powder deposition in the conveyor belt direction; applying additional voltage can increase the strength of the static charge carried by the powder, so that the deposited powder layer resists the airflow disturbance during the conveyor belt operation, and effectively maintains the consistency of the powder layer before reaching subsequent processing steps such as rolling and baking. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Fig. 1 This is a front view of the device of the present invention viewed from the width direction of the base film belt.

[0022] Fig. 2 This is a side view of the device of the present invention viewed from the width direction of the base film belt.

[0023] Fig. 3 This is a schematic diagram of the V-shaped screen device of the present invention.

[0024] In the diagram: 101, outer frame; 102, reciprocating slide rail; 103, inner frame; 104, porous inner wall box; 105, upper box air inlet; 106, laminar flow air inlet; 107, lower box air inlet; 108, box temperature control pipe; 201, powder conveying pipe; 202, vibrating comb; 2021, driver; 2022, comb teeth; 203, powder discharge; 2041, reciprocating drive block; 2042, reciprocating drive wheel; 205, distribution hopper; 206, powder layer inside the distribution hopper; 301, pinwheel driver; 302. 303. First rotating pinwheel assembly; 304. Second rotating pinwheel assembly; 305. Laminar gas nozzle; 306. Laminar gas electrostatic electrode; 307. Laminar gas electrostatic electrode wire; 308. V-shaped screen device; 309. Screen drive motor; 3002. V-shaped screen; 3003. Filter residue collector; 3004. Screen electrode wire; 3006. Electrostatic restraint device; 30061. High voltage power line; 30062. Insulating support block; 301. Sieve powder; 402. Belt-carrying base film; 403. Deposited powder layer; 404. Base film support plate. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0029] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0030] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0032] The device of the present invention overcomes the problem of uneven deposition thickness in the belt width direction of the cluster nozzle method, and also solves the disadvantage of the existing powder deposition method having many surface defects. It is particularly suitable for the high-precision production of polymer-coated micron-sized solid particle powder layers, such as positive electrode sheets, negative electrode sheets, or solid electrolyte separators, capacitor plates and other energy storage device membrane materials, and comprehensively improves the performance and production efficiency of energy storage devices.

[0033] The polymers include: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene oxide (PEO), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN), polyacrylic acid (PAA), polyvinyl alcohol (PVA), sodium alginate (Alg), β-cyclodextrin polymer (β-CDp), and other electrochemically stable viscous polymer materials.

[0034] In addition, the polymer also includes one or more additives to improve the performance of the coating layer, including conductive agents such as carbon black, porous carbon, carbon nanotubes, carbon fibers, modified graphene, conductive carbon black or micron-sized metal fibers; and electrolyte additives such as lithium bis(trifluoromethanesulfonylimide) (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium perchlorate (LiClO4).

[0035] Micron-sized solid particles include: nickel-cobalt-manganese ternary cathode materials, lithium iron phosphate-manganese iron phosphate cathode materials, silicon-carbon anode materials, solid electrolyte materials, porous carbon capacitor electrode materials, micron-sized metal particle materials, silicon carbide abrasives, silica spheres, passivated lithium powder, and other functional materials. The equipment of this invention exhibits good material and environmental compatibility; however, appropriate process or component parameters need to be selected based on the viscosity, particle size, and other parameters of each component powder.

[0036] like Figs. 1-3 As shown, this invention provides a wide-width vapor-phase dispersion powder electrostatic deposition device, which is a powder deposition equipment for preparing high-capacity ion battery positive and negative electrodes, solid electrolytes, and supercapacitor electrodes. This device is used for wide-width uniform electrostatic dispersion of micron-sized powder particles and deposition onto a transportable substrate film. Traditional vapor-phase dispersion uses a turbulent carrier gas to blow out the powder in a tube; however, this can lead to excessive collision and agglomeration of the powder during blowing, resulting in uneven powder mist. This device separates the powder feed rate from the traditional vapor-phase dispersion carrier gas flow, avoiding excessive collisions between powder particles that could cause agglomeration or nozzle blockage. By applying an ionized laminar flow field, the electrostatic repulsion between powder particles can be increased and aerodynamic collision disturbances reduced. It can be used for quantitative powder laying with different fluid properties, and the powder outlet width can be adjusted to adapt to transportable substrate films with different width requirements. The concentrated powder outlet range reduces powder waste and other problems.

[0037] The device is based on functional modules, specifically including: A reciprocating guide discharge module is used to uniformly supply and initially distribute powder along the width direction. The reciprocating guide discharge module includes a powder conveying pipe 201 that reciprocates along the width direction and a vibrating comb 202 disposed at the discharge end of the powder conveying pipe 201. Here, the width direction refers to the direction perpendicular to the conveying direction of the conveyor belt base film 401 in the plane where the conveyor belt base film 401 is located.

[0038] The powder distribution module, located below the vibrating comb 202, is used to receive and buffer the powder output from the reciprocating guide discharge module. The powder distribution module includes a distribution hopper 205 extending in the width direction.

[0039] The powder dispersion module, located below the discharge port of the distribution hopper 205, is used to electrostatically disperse the powder and accelerate its descent. The powder dispersion module includes a first rotating pinwheel assembly 302, a second rotating pinwheel assembly 303, and a laminar air nozzle 304 arranged sequentially along the powder's descent direction. The acceleration principle of the powder dispersion module is as follows: the second rotating pinwheel rotates at a higher speed than the first rotating pinwheel, providing mechanical acceleration, further accelerated by laminar airflow. The higher speed of the second rotating pinwheel helps to clean the first pinwheel and accelerate the powder, stretching the discharged powder stream.

[0040] The screening and recovery module, located below the powder dispersion module, is used to screen the falling powder. The screening and recovery module includes a V-shaped screen device 305.

[0041] The powder deposition and confinement module includes a conveyor assembly for carrying and transporting the conveyor base film 401, and electrostatic confinement devices 306 symmetrically arranged below the screening and recovery module and distributed along the width direction to confine the falling path of the powder.

[0042] In one specific embodiment, the reciprocating guide discharge module, powder distribution module, powder dispersion module, screening and recovery module, and powder deposition and constraint module are disposed within the external frame 101.

[0043] A crossbar is provided in the upper part of the interior of the outer frame 101. The crossbar is arranged along the width direction and a reciprocating slide rail 102 is provided on the crossbar. A reciprocating driver is provided on the reciprocating slide rail 102, and a powder conveying pipe 201 is fixed to the reciprocating driver in the vertical direction. A vibrating comb 202 is fixed to the lower end of the powder conveying pipe 201. Powder is conveyed through the powder conveying pipe 201 and driven by the reciprocating driver, so that the powder conveying pipe 201 slides horizontally back and forth along the reciprocating slide rail 102. The vibrating comb 202 is fixed to the end of the powder conveying pipe 201 and driven by the vibrating comb driver 2021. The comb teeth 2022 of the vibrating comb 202 are used to vibrate and comb the powder outlet 203, level its upper surface, and form a stable powder pressure at the lower end of the distribution hopper 205.

[0044] An internal frame 103 is installed below the crossbar. A perforated inner wall box 104 is installed inside the internal frame 103. The perforated inner wall box 104 has an opening at the top, and a distribution hopper 205 is installed at the opening along its width. The lower part of the comb teeth 2022 of the vibrating comb 202 extends into the distribution hopper 205. The distribution hopper 205 is located directly below the powder conveying pipe 201 and the vibrating comb 202. The width of the distribution hopper 205 is consistent with the reciprocating direction of the powder conveying pipe 201, and the width of the distribution hopper 205 covers the trajectory of the discharge end of the powder conveying pipe 201 during reciprocating motion. It is used to receive the powder flowing out of the powder conveying pipe 201 and accumulate it along the width direction of the distribution hopper 205. The comb teeth 2022 of the vibrating comb 202 extend into the powder layer in the distribution hopper 205, and reciprocate to comb, compact, and level the powder in the distribution hopper 205 as the powder conveying pipe 201 moves. The internal frame 103 has an upper chamber air inlet 105, a laminar flow air inlet 106, and a lower chamber air inlet 107 symmetrically arranged from top to bottom on its front and rear side walls. A chamber temperature control pipe 108 is installed inside the porous inner wall chamber 104. External gas enters the upper end of the porous inner wall chamber 104 through the upper chamber air inlet 105 and enters the lower end of the porous inner wall chamber 104 through the lower chamber air inlet 107. Gas inside the porous inner wall chamber 104 is discharged through the porous inner wall to prevent powder from falling onto the inner wall.

[0045] In the porous inner wall box 104 at the bottom of the distribution hopper 205, a first rotating pinwheel group 302, a second rotating pinwheel group 303, a laminar flow air nozzle 304 and a V-shaped screen device 305 are arranged sequentially from top to bottom.

[0046] The porous inner wall box 104 is located inside the internal frame 103. The inner surface of the porous inner wall box 104 has a porous structure to allow airflow and prevent dust from adhering to the inner wall. The porous inner wall box 104 is equipped with a box temperature control tube 108.

[0047] The first rotating needle wheel assembly 302 consists of two relatively rotating needle wheels, mounted below the dispensing hopper 205 and close to the discharge port of the dispensing hopper 205. The width of the first rotating needle wheel assembly 302 is greater than the width of the dispensing hopper 205, and the needle lengths of the first rotating needle wheel assembly 302 are the same and equal to the distance between the surfaces of the two needle wheel rollers. The second rotating needle wheel assembly 303 also consists of two relatively rotating needle wheels, mounted below the first rotating needle wheel assembly 302. The needle length of the second rotating needle wheel assembly 303 is equal to the distance between the roller surfaces of this needle wheel and the nearest needle wheel in the first rotating needle wheel assembly 302. The needle length of the second rotating needle wheel assembly 303 is greater than the needle length of the first rotating needle wheel assembly 302, preferably 1.1-2.0 times the needle length of the first rotating needle wheel assembly, and the rotational linear velocity of the second rotating needle wheel assembly 303 is also greater than that of the first rotating needle wheel assembly 302, preferably 1.1-5.0 times the needle length of the first rotating needle wheel assembly. The first rotating pinwheel assembly 302 and the second rotating pinwheel assembly 303 are electrically connected to the pinwheel driver 301.

[0048] Laminar flow gas nozzles 304 are symmetrically arranged in the middle of the porous inner wall box 104, connecting to the laminar flow gas inlet. The end of the laminar flow gas nozzle 304 is located below the second rotating needle wheel assembly 303. Laminar flow gas enters through the laminar flow gas inlet 106. The laminar flow gas nozzle 304 is equipped with a laminar flow gas electrostatic electrode 3041 for ionizing the laminar flow gas. The laminar flow gas electrostatic electrode 3041 is connected to the laminar flow gas electrostatic electrode wire 3042.

[0049] A V-shaped screen device 305 is installed between the dispersed powder falling path and the conveyor belt base membrane 401. The V-shaped screen 3052 of the V-shaped screen device 305 causes powder particles larger than the mesh size to roll towards the lowest point on the surface of the V-shaped screen 3052, while qualified powder particles smaller than the mesh size are evenly spread. The width of the V-shaped screen 3052 is greater than the powder falling width. A filter residue collector 3053 is located at one end of the V-shaped screen device 305. A screen drive motor 3051 drives the V-shaped screen 3052 to vibrate, conveying large particles located at the bottom of the V-shaped screen 3052 to the filter residue collector 3053 for recovery. The V-shaped screen 3052 is connected to the screen electrode wire 2054.

[0050] The electrostatic confinement device 306 consists of two sets of insulating support blocks 3062, two sets of high-voltage linear electrodes, and two sets of high-voltage power lines 3061. The two sets of insulating support blocks 3062 are symmetrically located at the bottom of the porous inner wall box 104. The two sets of insulating support blocks 3062 respectively support the two sets of high-voltage linear electrodes distributed along the deposition width direction. The high-voltage power lines 3061 introduce high voltage and connect to both sides of the electrodes.

[0051] The rollers of the first rotating needle wheel assembly 302 and the second rotating needle wheel assembly 303 can be made of wear-resistant metal materials, preferably stainless steel. The surface needles of the first rotating needle wheel assembly 302 and the second rotating needle wheel assembly 303 can be hard single needles or soft polymer needles, and the needle material can be stainless steel, plastic steel, PVC, PC, PE, etc. The needle density of the first rotating needle wheel assembly 302 and the second rotating needle wheel assembly 303 is selected according to the powder size and material. For high-viscosity, low-density powders, low-density, high-elasticity needles are preferred; for low-viscosity, high-density powders, high-density, low-elasticity needles are preferred, but the needle spacing should be 5-20 times greater than the powder's D50 particle size. The angle of repose of high-viscosity, low-density powders is >75°, and the compacted density is <2.5 g / cm³. 3 The angle of repose for stacking low-viscosity, high-density powders is <45°, and the compacted density is >2.5 g / cm³. 3 .

[0052] The porous inner wall box 104 can be made of smooth insulating materials such as ceramics, plexiglass, or polytetrafluoroethylene (PTFE). The diameter of the holes on the inner wall surface of the porous inner wall box 104 can be 0.05-2.00 mm, and the density is 10-40 holes per square centimeter. The heating device for the porous inner wall box 104 can be electric heating or oil heating, and the temperature range can be from room temperature to 200℃.

[0053] The dimensions of the powder conveying pipe 201, the width of the distribution hopper 205, the width of the vibrating comb 202, and the width of the rotating pinwheel assembly are all selected according to the width of the deposited conveyor belt base film 401, and are usually 2-5% wider at both ends than the width of the conveyor belt base film 401. Among them, the vibrating comb driver 2021 can be electric or pneumatic, and the screen drive motor 3051 is electrically driven.

[0054] A substrate film 401 is disposed at the lower part of the internal frame 103. The upper surface of the substrate film 401 is used to receive deposited powder to form a deposited powder layer 402. A substrate film support plate 403 is fixedly disposed on the substrate film 401 away from the deposition direction. The substrate film support plate 403 is placed horizontally on the ground by a support frame. The height of the substrate film support plate 403 is adjustable, and a heating element is provided inside the substrate film support plate 403. The surface of the substrate film support plate 403 in contact with the substrate film 401 is made of smooth stainless steel and is grounded with low resistance.

[0055] The working principle and preferred parameter range of this invention are as follows: The substrate film 401 to be deposited is laid on top of the substrate film support plate 403. The conveyor belt running speed is set to 5-30 m / min and the conveyor belt is started. The heating temperature of the substrate film support plate 403 is set and heating is started; the temperature can be from room temperature to 200℃. After the surface temperature of the conveyor belt stabilizes, the temperature control pipe 108 in the porous inner wall box 104 is set and started. After the temperature inside the box reaches the set value, the powder conveying program is started.

[0056] The dried deposited powder is conveyed to the outlet of the powder conveying pipe 201 through a positive and negative pressure airflow conveying system. The vibrating comb 202 is kept vibrating at a fixed frequency to ensure a uniform powder outflow rate. The reciprocating drive is started, and the reciprocating drive wheel 2042 drives the reciprocating drive block 2401 and the powder conveying pipe 201 to reciprocate along the width direction, so that the powder output 203 falls into the distribution hopper 205 to form a powder layer 206 in the distribution hopper.

[0057] After the powder layer 206 in the hopper is leveled and filled to the set depth, the porous inner wall box 104 is started to supply air with a positive pressure range of 0.5-500kPa. The power supply and air supply of the first rotating pinwheel group 302, the second rotating pinwheel group 303 and the laminar flow air nozzle 304 are started, and the power supply of the V-shaped screen device 305 and the electrostatic restraint device 306 is connected.

[0058] The linear velocity of the first rotating pinwheel assembly 302 is controlled to maintain a constant depth of the powder layer 206 in the distribution hopper, ensuring the feed rate equals the discharge rate. The linear velocity of the second rotating pinwheel assembly 303 is controlled to be 1-10 times that of the first rotating pinwheel assembly 302. Adjusting the laminar gas ionization voltage to 15-80kV with the same amplitude, and adjusting the airflow size of the left and right nozzles with the same amplitude, allows the powder to fall smoothly along the central axis. Adjusting the voltage of the electrostatic confinement device 306 to be equal to the laminar gas ionization voltage (range 15-80kV) prevents powder deposition on the electrode surface, thus confining the powder to fall near the central axis.

[0059] The mesh size of the V-shaped 3052 sieve is selected based on the powder size. For powders with a D50 diameter of 5-20μm, a mesh size of 150-400 can be used. The mesh size is generally 3-8 times the D50 diameter of the monodisperse powder. The amplitude of the V-shaped 3052 sieve can be 0.5-2.0mm, and the vibration frequency can be dynamically adjusted within the range of 10-500Hz according to the powder material, preferably 50-200Hz.

[0060] After the powder is sieved through the V-shaped screen 3052, the qualified sieved powder 307 falls onto the surface of the conveyor belt base membrane 401 and forms a deposited powder layer 402 under the electric field confinement generated by the linear confinement electrodes 15-80kV with the same charge. The large particles of powder that are screened out are transported to the filter residue collector 3053 for recovery.

[0061] Example 1 This embodiment utilizes carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) as binders and carbon black C65 and fumed carbon fiber VGCF as conductive agents to coat graphite electrode active material particles as deposition powder. The powder particle diameter D50 is 4μm. The specific steps for deposition onto the 14μm copper foil surface are as follows: The copper foil, serving as the base film 401, is laid on top of the base film support plate 403. The conveyor belt speed is set to 10 m / min and started. The heating temperature of the base film support plate 403 is set to 80℃ and started. The temperature control tube 108 in the porous inner wall box 104 is set to 5℃ to keep the temperature below the ambient temperature, preventing the styrene-butadiene rubber from liquefying due to high temperature, which would increase the viscosity of the powder and hinder its electrostatic dispersion. Dry air is used as the air source. After the surface temperature of the conveyor belt and the temperature inside the box stabilize, the powder conveying program is started.

[0062] The dried powder is conveyed to the outlet of the powder conveying pipe 201, and the vibrating comb 202 is kept vibrating. The reciprocating drive block 2041 is set to reciprocate at a fixed speed to make the powder fall evenly into the distribution hopper 205. After the powder layer 206 in the distribution hopper stabilizes, the porous inner wall box 104 is started to supply air at a positive pressure of 20 kPa, and the first rotating needle wheel group 302, the second rotating needle wheel group 303, the laminar flow air nozzle 304, the V-shaped screen device 305, and the electrostatic restraint device 306 are started.

[0063] The linear velocity of the first rotating pinwheel assembly 302 is controlled to maintain a constant powder layer depth, and the linear velocity of the second rotating pinwheel assembly 303 is controlled to be twice that of the first rotating pinwheel assembly 302. The ionization voltage of the laminar air nozzle 304 is adjusted to 20kV, and the voltage of the electrostatic confinement device 306 is adjusted to 55kV. A 400-mesh stainless steel V-shaped screen 3052 is selected, and the amplitude is set to 1.5mm and the frequency to 155Hz for sieving. Qualified powder is deposited on the surface of the copper foil, and large particles are recovered by the filter residue absorber 3053.

[0064] Example 2 In this embodiment, NCM811 electrode active material particles coated with PVDF binder and carbon black C65 conductive agent are used as deposition powder. The powder D50 is 10μm. The specific steps for deposition onto a 20μm aluminum foil surface are as follows: The aluminum foil serving as the conveyor base film 401 is laid on top of the base film support plate 403. The conveyor running speed is set to 5 m / min, and the heating temperature of the base film support plate 403 is set to 120℃. The temperature control tube 108 of the porous inner wall box 104 is set to 100℃, and the gas source is dry argon. The temperature control tube 108 preheats the powder, ensuring uniform temperature rise of the powder preheated by hot air, and preventing the powder coating layer from becoming too sticky, which would make it difficult for the powder to electrostatically disperse.

[0065] The powder conveying and module start-up process is the same as in Example 1. Parameters are set as follows: air supply pressure of the porous inner wall box 104 is 10 kPa; the linear velocity of the second rotating pinwheel assembly 303 is 5 times the linear velocity of the first rotating pinwheel assembly 302; the ionization voltage of the laminar flow nozzle 304 is 50 kV; and the voltage of the electrostatic confinement device 306 is 30 kV. A 400-mesh V-shaped screen 3052 is used, with an amplitude of 1.0 mm and a frequency of 115 Hz. Qualified powder is deposited on the aluminum foil surface, and large particles are recovered.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wide-width gas-phase dispersed powder electrostatic deposition device, characterized in that, include: A reciprocating guide discharge module is used to uniformly supply and initially distribute powder along the width direction. The reciprocating guide discharge module includes a powder conveying pipe that reciprocates along the width direction and a vibrating comb set at the discharge end of the powder conveying pipe. The powder distribution module, located below the vibrating comb, is used to receive and buffer the powder output from the reciprocating guide discharge module. The powder distribution module includes a distribution hopper extending in the width direction. The powder dispersion module is located below the discharge port of the distribution hopper. It is used to electrostatically disperse the powder and accelerate the powder falling. The powder dispersion module includes a first rotating needle wheel group, a second rotating needle wheel group, and a laminar air nozzle arranged sequentially along the powder falling direction. The screening and recovery module, located below the powder dispersion module, is used to screen the falling powder. The screening and recovery module includes a V-shaped screen device. The powder deposition and confinement module includes a conveyor assembly for carrying and transporting the conveyor base film, and electrostatic confinement devices symmetrically arranged below the screening and recovery module and distributed along the width direction to confine the falling path of the powder.

2. The wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to claim 1, characterized in that, The reciprocating guide discharge module, powder distribution module, powder dispersion module, screening and recovery module, and powder deposition and constraint module are set inside the external frame; A crossbar is provided in the upper part of the interior of the outer frame; the crossbar is provided in the width direction, a reciprocating slide rail is provided on the crossbar, a reciprocating driver is provided on the reciprocating slide rail, a powder conveying pipe is fixed to the reciprocating driver in the vertical direction, and a vibrating comb is fixed to the lower end of the powder conveying pipe. An internal frame is provided below the crossbar, and a perforated inner wall box is provided inside the internal frame. The perforated inner wall box has an opening at the top and a distribution hopper is provided at the opening along the width direction. The lower part of the vibrating comb extends into the distribution hopper. The porous inner wall box at the bottom of the distribution hopper is provided with a first rotating pinwheel group, a second rotating pinwheel group, a laminar air nozzle and a V-shaped screen device in sequence from top to bottom; The lower part of the internal frame is provided with a conveyor belt base film that is transported from front to back.

3. The wide-width gas-phase dispersed powder electrostatic deposition apparatus according to claim 2, characterized in that, The first rotating pinwheel assembly, the second rotating pinwheel assembly, the laminar air nozzle, and the V-shaped screen device are arranged along the width direction; The first rotating needle wheel assembly includes two relatively rotating first rotating needle wheels arranged in a front-to-back manner, and the first rotating needle wheel assembly is located at the outlet of the dispensing hopper; The second rotating needle wheel assembly includes two relatively rotating second rotating needle wheels arranged in a front-to-back manner, and the first rotating needle wheel assembly and the second rotating needle wheel assembly are electrically connected to the needle wheel driver; The laminar flow nozzle extends into the porous inner wall box from the laminar flow air inlet and is inclined downwards. The end of the laminar flow nozzle is located below the second rotating needle wheel assembly.

4. The wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to claim 3, characterized in that, The needle length of the first rotating needle wheel is equal to the minimum surface distance between the two first rotating needle wheels; the needle length of the second rotating needle wheel is equal to the minimum surface distance between the second rotating needle wheel and its nearest first rotating needle wheel. The needle length of the second rotating needle wheel is greater than that of the first rotating needle wheel, and the linear speed of rotation of the second rotating needle wheel group is greater than that of the first rotating needle wheel group.

5. The wide-width gas-phase dispersed powder electrostatic deposition apparatus according to claim 3, characterized in that, The laminar gas nozzle includes a laminar gas electrostatic electrode and a laminar gas electrostatic electrode line disposed inside the housing, and the laminar gas electrostatic electrode is connected to the laminar gas electrostatic electrode line.

6. The wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to claim 3, characterized in that, The reciprocating drive includes a reciprocating drive block and a reciprocating drive wheel connected together. The reciprocating drive wheel moves horizontally on a reciprocating slide rail, and the reciprocating drive block fixes the powder conveying pipe.

7. The wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to claim 1, characterized in that, The upper chamber air inlet, laminar flow air inlet, and lower chamber air inlet are symmetrically arranged from top to bottom on the front and rear side walls of the internal frame, and a chamber temperature control pipe is installed inside the porous inner wall chamber.

8. The wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to claim 1, characterized in that, A base film support plate and a support frame are arranged sequentially below the base film, and a heating device is installed inside the base film support plate.

9. The wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to claim 1, characterized in that, Each of the front and rear bottoms of the porous inner wall box is provided with a set of insulating support blocks. The insulating support blocks support the high-voltage linear electrodes distributed along the deposition width direction. The high-voltage linear electrodes are connected to the high-voltage power supply line.

10. A method of using a wide-width vapor-phase dispersed powder electrostatic deposition apparatus, implemented based on the wide-width vapor-phase dispersed powder electrostatic deposition apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Lay the base film and start the conveyor belt. Set and start the heating device of the base film support plate so that the surface temperature of the base film reaches and stabilizes at the first set temperature. S2. Set and activate the chamber temperature control tube in the porous inner wall chamber so that the temperature inside the chamber reaches and stabilizes at the second set temperature. S3. The dried deposited powder is conveyed through the powder conveying pipe, and the driver of the vibrating comb is started to make the powder flow out at a uniform rate. S4. Start the reciprocating drive to drive the powder conveying pipe to reciprocate along the width of the crossbar, so that the powder falls into the distribution hopper to form a powder layer; after the powder layer is stable, start the air supply system of the porous inner wall box, the pinwheel drive of the first and second rotating pinwheel groups, the air supply and power supply system of the laminar air nozzle, and the V-shaped screen device in sequence. S5. Adjust the rotational linear speed of the first rotating pinwheel group to keep the powder layer depth in the distribution hopper constant; adjust the rotational linear speed of the second rotating pinwheel group to 1 to 10 times the linear speed of the first rotating pinwheel group; adjust the laminar gas ionization voltage of the laminar gas nozzle to 15-80kV, and adjust the airflow size to make the powder stream fall stably. Adjust the vibration parameters of the V-shaped screen device; S6. The qualified powder that has been screened by the V-type screen device falls and is deposited on the surface of the conveyor belt base film under the electric field constraint generated by the linear constraint electrode with the same charge of 15-80kV to form a powder layer. The large particles of powder that have been screened out are recovered by the V-type screen device.

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