A screw granulation device for dry electrode processing

Abstract

This application relates to the field of material extrusion equipment technology, and in particular to a screw granulation device for dry electrodes, comprising a barrel and a temperature control structure disposed on the barrel, and an extrusion structure disposed on the barrel; the barrel has an extrusion chamber, and the extrusion structure includes a plurality of extrusion screws rotatably connected to the extrusion chamber and a drive assembly for driving the extrusion screws; the extrusion screws are sequentially arranged along their length as a conveying section, a pre-shearing section, a mixing section, a first dispersion section, a second dispersion section, and a granulation section; the drive assembly is disposed at one end of the barrel and connected to the extrusion screws. When the material passes through the mixing section, the first dispersion section, the second dispersion section, and the granulation section, the various functional sections work together to mix and disperse the material, such as PTFE, multiple times, avoiding material blockage in the extrusion screws, allowing direct dry coating without secondary grinding, thereby effectively improving the dispersion effect and flowability of the electrode extrusion and ensuring the stability of the electrode mixture performance.

Description

Technical Field

[0001] This application relates to the field of material extrusion equipment technology, and in particular to a screw granulation device for dry electrode. Background Technology

[0002] A screw extruder is an extrusion equipment that includes a barrel and a screw installed inside the barrel. When used for electrode preparation, the screw is driven to rotate by a motor. Dry materials enter the barrel through the feeding hopper, and under the drive of the motor, the screw conveys, shears, mixes, disperses and fibers the materials, which are then extruded through the discharge hopper.

[0003] Screw extruders have a relatively simple structure and good temperature control, which can basically meet the initial production needs of dry-process electrode materials. However, conventional screw extruders are mainly designed for melt molding of thermoplastic engineering plastics (such as polypropylene masterbatch), resulting in a low degree of matching for mixing and dispersion functions. The polytetrafluoroethylene (PTFE) binder in dry-process electrode materials is prone to agglomeration due to its inherent characteristics and does not require melt processing. When extruded using a conventional screw extruder, on the one hand, the dispersion effect of dry materials is poor, the screw gaps are easily clogged, making it difficult for PTFE to be fully fiberized and evenly distributed. The agglomerates are large, requiring secondary grinding, which affects production efficiency and electrode performance. On the other hand, the dry materials have poor flowability and poor sphericity, easily leading to edge defects in the films obtained during subsequent rolling stages. Utility Model Content

[0004] The purpose of this application is to provide a screw granulation device for dry electrode extrusion, which aims to improve the problems of poor dispersion and poor flowability of screw extruders used for dry electrode extrusion in related technologies, and improve the mixing and dispersion effect of screw extruders on dry materials.

[0005] This application provides a screw granulation apparatus for dry electrode production, including a barrel and an extrusion structure disposed on the barrel. The barrel has an extrusion chamber, and the extrusion structure includes a plurality of extrusion screws rotatably connected to the extrusion chamber and a drive assembly for driving the extrusion screws. The extrusion screws are sequentially provided with a conveying section, a pre-shearing section, a mixing section, a first dispersion section, a second dispersion section, and a granulation section along their length. The drive assembly is disposed at one end of the barrel and connected to the extrusion screws.

[0006] Furthermore, the mixing section includes a plurality of meshing blocks disposed on the extrusion screw, the plurality of meshing blocks being uniformly disposed and adjacent to each other along the extrusion screw, and the included angle between the central axes of adjacent meshing blocks being 60°-120°.

[0007] Furthermore, the first dispersing section includes a plurality of first gear blocks spaced apart from each other on the extrusion screw, and the plurality of first gear blocks on the extrusion screw are staggered relative to each other; the second dispersing section includes a plurality of second gear blocks spaced apart from each other on the extrusion screw, and the plurality of second gear blocks on the extrusion screw are staggered relative to each other.

[0008] Furthermore, the granulation section is conical in shape, having a coarse end and a fine end. The fine end is located on the side of the extrusion screw closer to the second dispersion section, and the coarse end is located on the side of the extrusion screw away from the second dispersion section.

[0009] Furthermore, the granulation section is provided with fish-scale patterns along its length to increase friction and conveying threads for transporting materials.

[0010] Furthermore, a transport section is provided between the mixing section, the first dispersion section, the second dispersion section and the granulation section, and the transport section includes a transport thread provided on the extrusion screw.

[0011] Furthermore, it also includes a discharge structure disposed on one side of the barrel along its length, the discharge structure including a discharge hopper connected to the extrusion chamber and a collection tank disposed on the discharge hopper; the discharge hopper is inclined and is provided with a filter screen, the filter screen being located above the collection tank.

[0012] The beneficial effects of this application are:

[0013] 1. A screw granulation device for dry electrodes according to this application, wherein several conveying screws are arranged in the barrel, and the conveying screws are sequentially arranged with a conveying section, a pre-shearing section, a mixing section, a first dispersion section, a second dispersion section and a granulation section. When the dry material enters the barrel, it is conveyed and extruded along the length of the conveying screw. After the conveying section quickly feeds the material into the extrusion chamber, the pre-shearing section first performs preliminary shearing on the material. Subsequently, the material passes through the mixing section, the first dispersion section, the second dispersion section and the granulation section. The various functional sections work together to mix and disperse the material, such as PTFE, multiple times, promote the full fiberization of the material, significantly reduce the agglomeration size of the material, avoid the material clogging the extrusion screw, and allow for direct dry coating without secondary grinding, thereby effectively improving the dispersion effect and flowability of the electrode extrusion and ensuring the stability of the electrode mixture performance.

[0014] 2. The screw granulation device for dry electrodes of this application has a discharge structure with an inclined discharge hopper and a filter screen. When the material is extruded, it slides along the inclined direction of the discharge hopper. The discharge hopper uses gravity to guide the material to roll, which is conducive to the further rotational molding of the material into spherical shapes and ensures that the particle shape is regular. At the same time, during the rolling and falling process of the material, the fine powder that does not form qualified spherical particles will be screened out through the mesh of the filter screen and fall into the collection tank below for centralized collection and processing. This allows the screw granulation device to perform initial screening of the material, prevent unqualified materials from entering the next process, and ensure the granulation quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a screw granulation device for dry electrodes provided in an embodiment of this application;

[0016] Figure 2 This is a cross-sectional schematic diagram of a screw granulation device for dry electrodes provided in an embodiment of this application;

[0017] Figure 3 This is a schematic diagram of the extrusion screw structure in an embodiment of this application;

[0018] Figure 4 yes Figure 3 A magnified view of part A in the middle;

[0019] Figure 5 yes Figure 3 A magnified view of part B in the middle section;

[0020] Figure 6 This is a schematic diagram of the granulation section in an embodiment of this application;

[0021] Figure 7 This is a schematic diagram of the material discharge structure in an embodiment of this application.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Barrel; 11. Feed hopper; 2. Temperature control structure; 21. Heating assembly; 22. Cooling assembly; 3. Extrusion structure; 31. Extrusion screw; 311. Conveying section; 312. Pre-shearing section; 313. Mixing section; 3131. Meshing block; 314. First dispersion section; 3141. First gear block; 315. Second dispersion section; 316. Granulation section; 3161. Coarse end; 3162. Fine end; 3163. Fish scale pattern; 3164. Conveying thread; 317. Transport section; 32. Drive assembly; 321. Gearbox; 322. Motor; 4. Discharge structure; 41. Discharge hopper; 411. Filter screen; 42. Collection tank. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0025] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0027] Reference Figure 1 as well as Figure 2 This application provides a screw granulation device for dry electrode, including a barrel 1 and a temperature control structure 2 disposed on the barrel 1, and an extrusion structure 3 disposed on the barrel 1. When the screw granulation device is running, the temperature control structure 2 is used to control the temperature inside the barrel 1 so as to cooperate with the extrusion structure 3 to perform extrusion. The extrusion structure 3 shears and disperses the material to achieve granulation.

[0028] Reference Figure 2 as well as Figure 3 Specifically, the barrel 1 is horizontally positioned and has an extrusion chamber. A feeding hopper 11, connected to the extrusion chamber, is located at one end of the barrel 1 along its length. Dry materials are fed into the extrusion chamber through the feeding hopper 11. The feeding hopper 11 also has an exhaust port connected to the extrusion chamber. The temperature control structure 2 includes a heating component 21 and a cooling component 22 disposed on the barrel 1. The heating component 21 can be electromagnetic heating, or it can be an induction heating coil, steam heating pipe, or heat transfer oil heat pipe. The cooling component 22 includes several condensation pipes, which cool the inside of the barrel 1 using water cooling. The cooling component 22 can also be an air-cooled structure, as long as it can adjust the temperature inside the barrel 1 as needed. Both the barrel 1 and the temperature control structure 2 are existing technologies and can be purchased; their specific structures and working principles will not be described in detail here.

[0029] The extrusion structure 3 includes a plurality of extrusion screws 31 rotatably connected to the extrusion chamber and a drive assembly 32 for driving the extrusion screws 31. The drive assembly 32 is disposed at one end of the barrel 1 and connected to the extrusion screws 31. In this embodiment, there are three extrusion screws 31, which are arranged parallel to each other and in a straight line. The three extrusion screws 31 extend along the length direction of the extrusion chamber. The drive assembly 32 includes a gearbox 321 disposed at one end of the barrel 1 and a motor 322 connected to the gearbox 321. The gearbox 321 is located between the extrusion screws 31 and the motor 322 and is connected to both the extrusion screws 31 and the motor 322. The power generated by the motor 322 is converted and transmitted through the gearbox 321. The gearbox 321 adjusts the rotational speed and distributes the torque, thereby driving the three extrusion screws 31 arranged in a straight line inside the barrel 1 to rotate synchronously.

[0030] To improve the processing efficiency of dry materials, the extrusion screw 31 is sequentially equipped with a conveying section 311, a pre-shearing section 312, a mixing section 313, a first dispersion section 314, a second dispersion section 315, and a granulation section 316 along its length. The conveying section 311 includes several conveying threads arranged along the length of the extrusion screw 31, and the pre-shearing section 312 includes several shearing threads arranged along the length of the extrusion screw 31. The pitch of the conveying threads is larger than that of the shearing threads. When material passes through the conveying threads, the larger pitch allows the material to quickly pass through the conveying section 311 and enter the pre-shearing section 312. When the material enters the pre-shearing section 312, the smaller pitch of the shearing threads pre-shears the dry material. The pre-shearing section 312 is located at the position corresponding to the heating component 21. It is understood that the pitches of the conveying section 311 and the pre-shearing section 312 can be adjusted according to actual needs, thereby regulating the conveying speed and shearing effect of the dry material.

[0031] Reference Figure 3 as well as Figure 4The mixing section 313 includes several meshing blocks 3131 disposed on the extrusion screw 31. The meshing blocks 3131 are evenly arranged and adjacent to each other along the length of the extrusion screw 31. The meshing blocks 3131 are generally rhomboid in shape, so that both sides of the meshing blocks 3131 have protrusions. For ease of description, the line connecting the two protrusions of the meshing blocks 3131 is taken as the central axis of the meshing blocks 3131. The included angle between the central axes of adjacent meshing blocks 3131 is 60°-120°. In this embodiment, the included angle between the central axes of adjacent meshing blocks 3131 is 90°. When the extrusion screw 31 rotates, the meshing blocks 3131 of adjacent extrusion screws 31 cooperate to generate shearing, kneading and stirring effects on the material: on the one hand, it can promote the fiberization of PTFE under stress, so that the fibers gradually become finer and dispersed from a coarse state; on the other hand, it can enhance the uniformity of the mixing of materials, such as active materials and PTFE, laying the foundation for further processing in the subsequent dispersion section, while avoiding uneven material processing caused by shearing in one direction.

[0032] Reference Figure 3 as well as Figure 5 The first dispersion section 314 and the second dispersion section 315 are used to disperse the material multiple times. The first dispersion section 314 and the second dispersion section 315 have the same structure. In this embodiment, the first dispersion section 314 includes a plurality of first gear blocks 3141 spaced apart on the extrusion screw 31, and the plurality of first gear blocks 3141 on the extrusion screw 31 are staggered with each other; the second dispersion section 315 includes a plurality of second gear blocks spaced apart on the extrusion screw 31, and the plurality of second gear blocks on the extrusion screw 31 are staggered with each other. With this arrangement, the gear blocks of the first dispersion section 314 and the second dispersion section 315 are arranged crosswise on the three extrusion screws 31. When the screws rotate, the teeth of the crosswise arranged gear blocks interlock and mesh with each other, forming a high-frequency, multi-angle shearing and dispersion effect on the material. When applied to dry materials, it can further break down the macroscopic agglomeration of residual PTFE fibers after mixing, and by precisely controlling the shear strength, it can avoid excessive stress that could cause the active material particles to break or the PTFE fibers to tear, ultimately achieving efficient dispersion of the material and meeting the requirements of dry coating for material dispersion.

[0033] Reference Figure 3 as well as Figure 6After passing through the first dispersion section 314 and the second dispersion section 315, the material enters the granulation section 316. The granulation section 316 is conical and has a coarse end 3161 and a fine end 3162. The fine end 3162 is located on the side of the extrusion screw 31 closer to the second dispersion section 315, and the coarse end 3161 is located on the side of the extrusion screw 31 further away from the second dispersion section 315. That is, the size of the granulation section 316 gradually increases along the material feeding direction. The granulation section 316 is provided with a fish-scale pattern 3163 to increase friction and a conveying thread 3164 for conveying material along its length. The fish-scale pattern 3163 covers the outer peripheral surface of the granulation section 316, and the conveying thread 3164 is provided along the outer peripheral surface of the granulation section 316 and rotates with the rotation of the extrusion screw 31. When the extrusion screw 31 rotates, the conical granulation section 316 gradually compresses the material during the conveying process. The conveying thread 3164 and the fish scale pattern 3163 work together. The propulsion force generated by the rotation of the conveying thread 3164 ensures that the material moves stably along the feed direction. The fish scale pattern 3163 increases the friction between the material and the surface of the extrusion screw 31, generating additional shearing action, promoting a more uniform distribution of dry materials such as PTFE fibers, achieving material homogenization, and ensuring consistent extruded material properties.

[0034] To ensure transportation efficiency, a transport section 317 is provided between the mixing section 313, the first dispersion section 314, the second dispersion section 315, and the granulation section 316. The transport section 317 includes a transport thread installed on the extrusion screw 31. The pitch of the transport thread is larger than that of the shearing thread; a larger pitch can be used for the transport thread to improve the transportation efficiency of dry materials. The core function of the mixing section 313, the first dispersion section 314, the second dispersion section 315, and the granulation section 316 is to mix, disperse, and homogenize the materials. Their structures, such as the meshing block 3131 and the gear block, focus on shearing and kneading, resulting in relatively weak conveying capacity. By setting up the transport section 311, its strong conveying characteristics can effectively compensate for the conveying shortcomings of the aforementioned functional sections, ensuring continuous and stable material flow between areas, avoiding material accumulation or processing interruptions due to insufficient conveying, and ensuring the smoothness of the overall extrusion process.

[0035] After the dry material enters the barrel 1 from the feeding hopper 11, it passes through various functional sections in sequence: the conveying section 311, with its high-efficiency conveying characteristics, initially conveys the material forward; the pre-shearing section 312, located in the area corresponding to the heating component 21, uses its shorter pitch to extend the material's residence time, and, in conjunction with the temperature control of the heating component 21, softens the PTFE while applying directional mechanical shearing force to break down the initial particle structure of the PTFE, creating stress conditions for subsequent fiberization. The mixing section 313 initiates PTFE fiberization in the shearing field; the first dispersion section 314 and the second dispersion section 315 grade and refine the fibers and disperse the active material agglomerates. Finally, the material passes through the granulation section 316 to form fiberized material particles. Volatile matter generated during the process is discharged through the exhaust port, and the finally qualified material is conveyed to the end of the barrel 1 via the granulation section 316.

[0036] Reference Figure 7 To ensure smooth material discharge, the screw granulator also includes a discharge structure 4 located on one side of the barrel 1 along its length. The discharge structure 4 includes a discharge hopper 41 connected to the extrusion chamber and a collection tank 42 located within the discharge hopper 41. A cooling assembly 22 at the front end of the discharge hopper 41 is specifically designed to cool the output material, which is then extruded through the discharge hopper 41. The discharge hopper 41 is inclined and equipped with a filter screen 411, located above the collection tank 42. Specifically, the discharge hopper 41 is inclined downwards, with the filter screen 411 located at the end of the discharge hopper 41 furthest from the barrel 1. The material, after being processed by the granulation section 316, enters the downwardly inclined discharge hopper 41 and rolls along the inclined direction under gravity. During this rolling process, the friction and extrusion forces between the materials and between the materials and the discharge hopper 41 interact, further shaping the material into spherical shapes. This effectively solves the problem of poor sphericity caused by poor material flowability, ensuring the regular shape of the granules.

[0037] Simultaneously, during the rolling descent of the material, fine powder that does not form qualified spherical particles will pass through the mesh of filter screen 411 and fall into the collection tank 42 below for centralized collection. This achieves both the formation and conveying of qualified spherical particles and the effective separation and recovery of fine powder, improving material utilization and ensuring the uniformity of the final product's particles. Understandably, the mesh size of filter screen 411 can be adjusted according to actual needs and process requirements to meet screening requirements.

[0038] The working principle of the screw granulation device for dry electrode processing disclosed in this application is as follows: Dry electrode material enters the barrel 1 through the feeding hopper 11. The motor 322 drives three extrusion screws 31 arranged in a straight line to rotate synchronously via the gearbox 321, initiating the material processing flow. The material first enters the conveying section 311, which smoothly pushes the material forward to provide continuous feed for subsequent processing. The material then enters the pre-shearing section 312, where the short-pitch screws extend the material residence time. Combined with the precise temperature control of the heating component 21, this allows the PTFE to reach a critical softening state. Simultaneously, the compression effect of the short-pitch screws generates directional mechanical shearing force, breaking down the van der Waals forces between PTFE particles and creating stress conditions for subsequent fiberization. Next, the material enters the mixing section 313, where multiple meshing blocks 3131 mesh with each other. Through strong shearing and kneading, the PTFE is fiberized and the fibers are refined, while simultaneously improving the uniformity of material mixing. The material is then conveyed via transport section 317 to the first dispersion section 314 and the second dispersion section 315. Cross-shaped gear blocks disperse the material; the first dispersion breaks down larger agglomerates, while the second dispersion further refines the material, significantly reducing agglomerate size. In granulation section 316, the material is pushed using conveyor threads 3164, and the fish-scale pattern 3163 enhances friction and shear force, resulting in a more uniform material density and fiber distribution. After processing in granulation section 316, the material enters the downward-sloping discharge hopper 41, where it rolls down the inclined hopper wall under gravity. During this rolling process, the friction and extrusion forces between the materials and between the materials and the hopper wall interact, gradually shaping the material into spherical shapes.

[0039] Exemplary embodiments of this disclosure have been specifically shown and described above. It should be understood that this disclosure is not limited to the detailed structures, arrangements, or implementations described herein; rather, this disclosure is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A screw granulator for dry electrode comprising a barrel (1) characterized in that, It also includes an extrusion structure (3) disposed on the barrel (1); the barrel (1) has an extrusion chamber, the extrusion structure (3) includes a plurality of extrusion screws (31) rotatably connected to the extrusion chamber and a drive assembly (32) for driving the extrusion screws (31); the extrusion screws (31) are provided with a conveying section (311), a pre-shearing section (312), a mixing section (313), a first dispersion section (314), a second dispersion section (315) and a granulation section (316) in sequence along their length direction; the drive assembly (32) is disposed at one end of the barrel (1) and connected to the extrusion screws (31).

2. The screw granulator for dry electrode according to claim 1, characterized in that, The mixing section (313) includes a plurality of meshing blocks (3131) disposed on the extrusion screw (31). The plurality of meshing blocks (3131) are evenly disposed and adjacent to each other along the extrusion screw (31), and the included angle between the central axes of adjacent meshing blocks (3131) is 60°-120°.

3. The screw granulator for dry electrode according to claim 1, characterized in that, The first dispersing section (314) includes a plurality of first gear blocks (3141) spaced apart from each other on the extrusion screw (31), and the plurality of first gear blocks (3141) on the extrusion screw (31) are staggered relative to each other; the second dispersing section (315) includes a plurality of second gear blocks spaced apart from each other on the extrusion screw (31), and the plurality of second gear blocks on the extrusion screw (31) are staggered relative to each other.

4. The screw granulator for dry electrode according to claim 1, characterized in that, The granulation section (316) is conical in shape and has a coarse end (3161) and a fine end (3162). The fine end (3162) is located on the side of the extrusion screw (31) closer to the second dispersion section (315), and the coarse end (3161) is located on the side of the extrusion screw (31) away from the second dispersion section (315).

5. The screw granulator for dry electrode according to claim 4, characterized in that, The granulation section (316) is provided with fish scale pattern (3163) for increasing friction and conveying thread (3164) for conveying materials along its length.

6. A screw granulator for dry electrode according to any one of claims 1 to 5, characterized in that, A transport section (317) is provided between the mixing section (313), the first dispersion section (314), the second dispersion section (315) and the granulation section (316), and the transport section (317) includes a transport thread provided on the extrusion screw (31).

7. The screw granulator for dry electrode according to claim 1, characterized in that, It also includes a discharge structure (4) disposed on one side of the barrel (1) along its length. The discharge structure (4) includes a discharge hopper (41) connected to the extrusion chamber and a collection tank (42) disposed on the discharge hopper (41). The discharge hopper (41) is inclined and is provided with a filter screen (411). The filter screen (411) is located above the collection tank (42).

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