Multi-screw extruder for dry-method electrode

Abstract

The utility model relates to the technical field of extrusion equipment, in particular to a multi-screw extruder for a dry-method electrode, which comprises a base and a machine barrel arranged on the base, and further comprises an extrusion structure and a temperature control structure arranged on the machine barrel, the extrusion structure comprises a planet wheel type extrusion assembly rotationally connected with the machine barrel and a driving assembly; the planet wheel type extrusion assembly comprises a main extrusion screw, a plurality of planet wheel type screws meshed with the main extrusion screw and an inner sleeve arranged on the planet wheel type screws in a wrapping mode, the planet wheel type extrusion assembly is provided with mixing plasticizing sections and conveying sections which are alternately arranged, and the thread pitch at the mixing plasticizing sections is smaller than the thread pitch at the conveying sections. The main extrusion screw and the planet wheel type screw work cooperatively, better shearing and stirring effects on materials can be achieved through the mixing and plasticizing section, the conveying efficiency of the materials can be guaranteed through the conveying section, and therefore the mixing effect and the conveying efficiency are both considered, and the mixing uniformity and the plasticizing quality of the materials are improved.

Description

Technical Field

[0001] This application relates to the field of extrusion equipment technology, and in particular to a multi-screw extruder for dry electrode fabrication. Background Technology

[0002] In the field of power battery manufacturing, compared with traditional wet coating, dry electrode technology has gradually become a key development direction for industry research and application due to its advantages such as environmentally friendly manufacturing process, thicker electrode sheets, and higher energy density. The mixing uniformity and mixing effect of dry electrode materials play a decisive role in the final electrode performance and affect the quality of the end battery.

[0003] Conventional extruders are mostly twin-screw extruders, which are not good at mixing materials when processing dry electrode materials: poor mixing uniformity, inadequate venting function, relatively high specific energy consumption, and significant shear heat. These defects are directly reflected in the produced electrode products, resulting in unstable performance and difficulty in meeting the production requirements of high-quality batteries for electrode consistency and stability. Utility Model Content

[0004] The purpose of this application is to provide a multi-screw extruder for dry electrode, which aims to improve the mixing quality and mixing efficiency of the extruder, and improve the mixing uniformity and plasticizing quality of the material.

[0005] This application provides a multi-screw extruder for dry electrode fabrication, including a base and a barrel disposed on the base, and further including an extrusion structure and a temperature control structure disposed on the barrel; the extrusion structure includes a planetary gear extrusion assembly and a drive assembly rotatably connected to the barrel; the planetary gear extrusion assembly includes a main extrusion screw, a plurality of planetary gear screws meshing with the main extrusion screw, and an inner sleeve covering the plurality of planetary gear screws; the planetary gear extrusion assembly has an alternately arranged mixing and plasticizing section and a conveying section, wherein the thread pitch at the mixing and plasticizing section is smaller than the thread pitch at the conveying section.

[0006] Furthermore, the mixing and plasticizing section and the conveying section are alternately arranged along the length direction of the main extrusion screw, the planetary gear screw, and the inner sleeve; a plurality of the planetary gear screws are evenly arranged along the circumferential direction of the main extrusion screw.

[0007] Furthermore, the drive assembly includes a motor disposed on one side of the barrel, a reducer disposed on the motor, and a transmission screw disposed on the reducer, the transmission screw being connected to the main extrusion screw.

[0008] Furthermore, the barrel has a feed hopper facing the conveying screw, which has helical blades arranged along its circumferential direction.

[0009] Furthermore, the barrel has a feed section for mounting the conveying screw, the feed section having a conical structure, and the diameter of the feed section gradually decreasing along the material conveying direction.

[0010] Furthermore, the barrel is provided with a plurality of air outlets along its length, and the plurality of air outlets are connected to the mixing and plasticizing section and the conveying section; a filter screen is provided in the air outlet.

[0011] Furthermore, the temperature control structure includes a heating layer disposed on the barrel, the heating layer being located between the outer wall of the barrel and the extrusion structure; an electromagnetic induction coil is disposed within the heating layer.

[0012] The beneficial effects of this application are:

[0013] 1. This application discloses a multi-screw extruder for dry electrode fabrication. By incorporating an extrusion structure and a temperature control structure within the barrel, the main extrusion screw of the planetary gear extrusion assembly works in tandem with the planetary gear screw, effectively increasing the contact area with the material and thus improving the mixing effect. Simultaneously, by arranging alternating mixing and plasticizing sections and conveying sections within the planetary gear extrusion assembly, with a smaller thread pitch in the mixing and plasticizing sections, the mixing and plasticizing sections achieve better shearing and mixing effects on the material, while the conveying sections ensure efficient material transport. This balances mixing effect and transport efficiency, which is beneficial for improving the mixing uniformity and plasticizing quality of dry electrode materials, especially the fiberization of polytetrafluoroethylene adhesives.

[0014] 2. This application discloses a multi-screw extruder for dry electrode fabrication. By setting a conveying screw with helical blades and a conical feeding section, the material fed from the hopper can quickly enter the feeding section and be conveyed and pre-treated by the conveying screw, thereby ensuring feeding efficiency and quality. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a multi-screw extruder for dry electrode provided in an embodiment of this application;

[0016] Figure 2 This is a cross-sectional schematic diagram of the multi-screw extruder in the embodiments of this application;

[0017] Figure 3 This is a schematic diagram of the planetary wheel extrusion assembly in an embodiment of this application;

[0018] Figure 4 This is a schematic diagram of the mating structure between the planetary wheel extrusion assembly and the barrel in an embodiment of this application.

[0019] Explanation of reference numerals in the attached figures:

[0020] 1. Base; 2. Barrel; 21. Feed hopper; 22. Feed section; 23. Air outlet; 231. Filter screen; 3. Extrusion structure; 31. Planetary gear extrusion assembly; 311. Main extrusion screw; 312. Planetary gear screw; 313. Inner sleeve; 314. Mixing and plasticizing section; 315. Conveying section; 32. Drive assembly; 321. Motor; 322. Reducer; 323. Conveying screw; 3231. Spiral blade; 4. Temperature control structure; 41. Heating layer. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Reference Figure 1 as well as Figure 2 This application provides a multi-screw extruder for dry electrode fabrication, including a base 1 and a barrel 2 disposed on the base 1, as well as an extrusion structure 3 and a temperature control structure 4 disposed on the barrel 2. During operation of the multi-screw extruder, dry electrode material is fed into the extrusion structure 3, which then inputs and uniformly mixes the material. The temperature control structure 4 controls the temperature inside the barrel 2.

[0025] Reference Figure 2 as well as Figure 3Specifically, the barrel 2 extends along the length of the base 1 and is horizontally positioned. An extrusion structure 3 is disposed within the barrel 2, comprising a planetary extrusion assembly 31 rotatably connected to the barrel 2 and a drive assembly 32. The planetary extrusion assembly 31 is used for uniformly mixing materials. The barrel 2 has an extrusion chamber, and the planetary extrusion assembly 31 is located within the extrusion chamber. The planetary extrusion assembly 31 includes a main extrusion screw 311, several planetary screws 312 meshing with the main extrusion screw 311, and an inner sleeve 313 covering the several planetary screws 312. The main extrusion screw 311 is located in the middle of the extrusion chamber, and the several planetary screws 312 are uniformly arranged along the circumferential direction of the main extrusion screw 311. The inner sleeve 313 extends along the length of the planetary screws 312, covering the outer side of the several planetary screws 312 and meshing with them. By configuring the planetary extrusion assembly 31 in this way, the main extrusion screw 311 can be driven to rotate by the drive assembly 32, which in turn drives several planetary screws 312 to rotate, thereby transporting and mixing the material.

[0026] To ensure efficient mixing and transport, the planetary extrusion assembly 31 has alternating mixing and plasticizing sections 314 and conveying sections 315, with the thread pitch in the mixing and plasticizing section 314 being smaller than that in the conveying section 315. More specifically, the mixing and plasticizing section 314 and the conveying section 315 are alternately arranged along the length of the main extrusion screw 311, the planetary screw 312, and the inner sleeve 313, i.e., the mixing and plasticizing section 314 and the conveying section 315 are intersected, and the thread pitch of the main screw, planetary screw 312, and inner sleeve 313 in the mixing and plasticizing section 314 is smaller than that in the conveying section 315. With this arrangement, in the mixing and plasticizing section 314, the thread pitch of the main screw, planetary screw 312, and inner sleeve 313 is smaller, resulting in stronger compression, shearing, and kneading effects on the material as it passes through. The smaller thread pitch increases the contact frequency and friction between the material and the screw and inner sleeve 313, promoting thorough kneading and dispersion of the material, especially facilitating the fiberization of the adhesive polytetrafluoroethylene. In the conveying section 315, the larger thread pitch facilitates rapid material transport, efficiently pushing the pre-plasticized material to the next stage.

[0027] Reference Figure 2 as well as Figure 4The drive assembly 32 includes a motor 321 mounted on one side of the barrel 2, a reducer 322 mounted on the motor 321, and a transmission screw 323 mounted on the reducer 322. The transmission screw 323 is connected to the main extrusion screw 311, and the transmission screw 323 and the main extrusion screw 311 are coaxially connected. The motor 321 generates power, which, after speed regulation by the reducer 322, drives the transmission screw 323 to rotate, thereby driving the main screw connected to it to rotate. During the rotation of the main screw, it drives multiple planetary gear screws 312 that are meshed around its outer wall to both rotate on their own axis and revolve around the central axis.

[0028] To ensure feeding speed and quality, the barrel 2 has a feed hopper 21 facing the conveying screw 323, which has helical blades 3231 arranged circumferentially. The barrel 2 also has a feed section 22 for mounting the conveying screw 323. The feed section 22 has a conical structure, and its diameter gradually decreases along the material conveying direction. Material enters the barrel 2 from the feed hopper 21. Under the action of the conveying screw 323, the rotational motion of the helical blades 3231 continuously conveys the material from the feed position to the extrusion chamber of the barrel 2, ensuring a continuous and stable flow of material into the extruder.

[0029] During the material conveying process, as the diameter of the conical structure gradually decreases, the extrusion pressure on the material gradually increases. This gradually increasing extrusion pressure helps to further compact the material, remove air from the material, and enhance the mixing and pre-plasticizing effect of the material, so that the material reaches a better state before entering the subsequent processing area. In addition, the planetary wheel extrusion assembly 31 can be limited by the smaller diameter end to prevent axial movement during its rotation.

[0030] Looking back Figure 1 as well as Figure 2 During the material extrusion process, volatile gases are generated, which need to be discharged promptly. The barrel 2 has several air outlets 23 along its length, connecting the mixing and plasticizing section 314 and the conveying section 315. Each air outlet 23 contains multiple layers of metal filters 231 with varying mesh sizes. Gas rises to the top of the barrel 2 and is discharged through the multiple evenly distributed air outlets 23. The multiple layers of metal filters 231 with different mesh sizes on the inner wall of the air outlets 23 filter the discharged gas, allowing it to pass smoothly through while any entrained material particles are intercepted and prevented from being discharged with the gas, thus achieving gas-solid separation.

[0031] The temperature control structure 4 includes a heating layer 41 disposed in the barrel 2, located between the outer wall of the barrel 2 and the extrusion structure 3. An electromagnetic induction coil (not shown in the figure) is disposed inside the heating layer 41, and the electromagnetic induction coil is wound inside the heating layer 41 and electrically connected to an external power source. When current passes through the electromagnetic induction coil, an alternating magnetic field is generated. The barrel 2, as a conductor, generates an induced current under the action of the alternating magnetic field. The induced current flows in the barrel 2 and generates Joule heat, thereby heating the material inside the barrel 2. By controlling the magnitude and frequency of the current, the heating power and temperature can be precisely adjusted, which helps to plasticize the material.

[0032] The working principle of the multi-screw extruder for dry electrode extrusion is as follows: the raw material for dry electrode extrusion enters the barrel 2 from the feed hopper 21. The motor 321 generates power to drive the conveyor screw 323 to rotate. The conical structure of the conveyor screw 323 and its corresponding position on the inner wall of the barrel 2 gradually increases the extrusion pressure on the material as the diameter decreases, compacting the material, removing air, and enhancing the mixing and pre-plasticizing effect. The main screw drives multiple planetary screws 312 that are meshed around its outer wall to both rotate on their own axis and revolve around the central axis. Inside the barrel 2, the material passes sequentially through the mixing and plasticizing section 314 and the conveying section 315. In the mixing and plasticizing section 314, the small thread spacing of the main screw, planetary screws 312, and inner sleeve 313 provides strong extrusion, shearing, and kneading to the material, promoting thorough mixing and plasticizing; the large thread spacing of the conveying section 315 efficiently pushes the pre-plasticized material to the next stage. The adhesive polytetrafluoroethylene undergoes shearing and fiberization; at the same time, the electromagnetic induction coil in the jacket of the barrel 2 generates an alternating magnetic field under the action of current, causing the barrel 2 to generate induced current and thus heat up, and precisely controlling the temperature to assist in the mixing of materials.

[0033] 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 multi-screw extruder for dry electrode fabrication, comprising a base (1) and a barrel (2) disposed on the base (1), characterized in that, It also includes an extrusion structure (3) and a temperature control structure (4) disposed on the barrel (2); the extrusion structure (3) includes a planetary gear extrusion assembly (31) and a drive assembly (32) rotatably connected to the barrel (2); the planetary gear extrusion assembly (31) includes a main extrusion screw (311), a plurality of planetary gear screws (312) meshing with the main extrusion screw (311) and an inner sleeve (313) covering the plurality of planetary gear screws (312); the planetary gear extrusion assembly (31) has an alternating mixing and plasticizing section (314) and a conveying section (315); the thread pitch at the mixing and plasticizing section (314) is smaller than the thread pitch at the conveying section (315).

2. The multi-screw extruder for dry electrode according to claim 1, characterized in that, The mixing and plasticizing section (314) and the conveying section (315) are alternately arranged along the length direction of the main extrusion screw (311), the planetary screw (312) and the inner sleeve (313); a plurality of the planetary screws (312) are uniformly arranged along the circumferential direction of the main extrusion screw (311).

3. A multi-screw extruder for dry electrode fabrication according to claim 1, characterized in that, The drive assembly (32) includes a motor (321) disposed on one side of the barrel (2), a reducer (322) disposed on the motor (321), and a transmission screw (323) disposed on the reducer (322), the transmission screw (323) being connected to the main extrusion screw (311).

4. A multi-screw extruder for dry electrode fabrication according to claim 3, characterized in that, The barrel (2) has a feed hopper (21) facing the conveying screw (323), and the conveying screw (323) is provided with helical blades (3231) in its circumferential direction.

5. A multi-screw extruder for dry electrode according to claim 4, characterized in that, The barrel (2) has a feed section (22) for mounting the conveying screw (323), the feed section (22) has a conical structure, and the diameter of the feed section (22) gradually decreases along the material conveying direction.

6. A multi-screw extruder for dry electrode according to any one of claims 1-5, characterized in that, The barrel (2) is provided with a plurality of air outlets (23) along its length, and the plurality of air outlets (23) are connected to the mixing and plasticizing section (314) and the conveying section (315); a filter screen (231) is provided in the air outlet (23).

7. A multi-screw extruder for dry electrode production according to any one of claims 1-5, characterized in that, The temperature control structure (4) includes a heating layer (41) disposed on the barrel (2), the heating layer (41) being located between the outer wall of the barrel (2) and the extrusion structure (3); an electromagnetic induction coil is disposed inside the heating layer (41).

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