Powder granulation mechanism and pole piece production system

Abstract

The present application discloses a powder granulation mechanism and an electrode production system, wherein the powder granulation mechanism comprises an inner cylinder, an outer cylinder, a suspension force supply device and a stirring device arranged in the inner cylinder, the inner cylinder is used to contain powder and binder, the inner cylinder and the outer cylinder are arranged at intervals from each other in their own radial direction and form a circulation channel, a plurality of first sieving holes are arranged through the wall of the inner cylinder, and the suspension force supply device is connected to the circulation channel; wherein the suspension force supply device can provide suspension force to the circulation channel. According to an embodiment of the present application, the powder granulation mechanism can mix and crush the mixture of powder and binder in the inner cylinder through the stirring device, the crushed particle structure flies into the circulation channel through the first sieving hole, and rolls and grinds under the action of the suspension force to improve the sphericity. The powder granulation mechanism can reduce the possible aggregation between the particle structures and improve the fluidity of the particle structure to improve the quality of the electrode.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a powder granulation mechanism and a pole piece production system. Background Art

[0002] In the preparation process of sheet structures, such as the preparation of battery pole pieces, powdered raw materials are usually formed into a granular structure with the help of a binder to facilitate subsequent feeding and other processes. After the granular structure is prepared, it is easy to agglomerate and cause defects such as uneven mixing and uneven density.

[0003] In the related art, a structure such as a screen is used to screen the particle structure. However, the vibration force and friction force during the screening process can easily destroy the binder in the particle structure, affect the strength of the sheet structure, and even cause the sheet structure to break during the rolling process. Utility Model Content

[0004] The present application provides a powder granulation mechanism and an electrode production system, which can prepare a particle structure that meets the particle size requirements while shaping the particle structure, improve the sphericity of the particle structure to enhance the fluidity of the material coming from the rolling mechanism, and reduce possible agglomeration between the particle structures.

[0005] In the first aspect, an embodiment of the present application provides a powder granulation mechanism, which includes an inner cylinder, an outer cylinder, a suspension force supply device and a stirring device arranged in the inner cylinder, which are arranged mutually. The inner cylinder is used to contain powder and binder, and the inner cylinder and the outer cylinder are arranged to be spaced apart from each other in their own radial direction and form a circulation channel. A plurality of first sieve holes are penetrated through the wall of the inner cylinder, and the suspension force supply device is connected to the circulation channel; wherein the suspension force supply device can provide suspension force to the circulation channel.

[0006] In the embodiment of the present application, the powder granulation mechanism is provided with a stirring device in the inner cylinder, and the stirring device can mix the powder and the binder in the inner cylinder and cut them into a particle structure. The particle structure with a particle size smaller than the first sieve hole can fly out of the inner cylinder through the first sieve hole into the circulation channel to reduce the agglomeration phenomenon that may occur between the particle structures. After the particle structure enters the circulation channel, since the particle structure has a linear velocity when flying out, and the suspension force supply device can provide suspension force to the particle structure to offset the self-weight of the particle structure, the particle structure can roll in the circulation channel to improve its own sphericity, improve the fluidity of the electrode production material, and improve the quality of subsequent processes.

[0007] In some optional embodiments, the inner cylinder and the outer cylinder are coaxially arranged, and the inner cylinder and the outer cylinder are relatively rotatable.

[0008] In these optional embodiments, the flow channel formed by the inner cylinder and the outer cylinder is uniform in shape, and the inner cylinder and the outer cylinder can rotate relative to each other and cooperate with the suspension force supply device to form a vortex, thereby increasing the disorder of the rolling motion of the particle structure in the flow channel, further improving the sphericity of the particle structure and accelerating the shaping of the particle structure.

[0009] In some optional embodiments, the stirring device is coaxially arranged with the inner cylinder, the inner cylinder is rotatably arranged in the outer cylinder, and the rotation speed of the inner cylinder is lower than the rotation speed of the stirring device.

[0010] In these optional embodiments, the probability of the particle structure formed by the crushing of the stirring device flying out from the first sieve holes on the wall of the inner cylinder tends to be the same, thereby reducing the probability of the particle structure gathering in a certain area in the flow channel. The rotation speed of the stirring device is higher than the rotation speed of the inner cylinder to achieve the effect of stirring, mixing and cutting and crushing the powder and binder.

[0011] In some optional embodiments, the difference between the rotation speed of the stirring device and the rotation speed of the inner drum is greater than or equal to 2000 rpm.

[0012] In these optional embodiments, there is a sufficient rotation speed difference between the stirring device and the inner cylinder to break the powder and the binder into a granular structure with a particle size smaller than the aperture size of the first sieve hole.

[0013] In some optional embodiments, the difference between the rotation speed of the stirring device and the rotation speed of the inner drum is less than or equal to 3000 rpm.

[0014] In these optional embodiments, the speed difference between the stirring device and the inner drum is within a reasonable range to avoid the particle size of the particle structure being too small and thus causing a negative impact on subsequent processes.

[0015] In some optional embodiments, the rotation speed of the stirring device is 3000-5000 rpm, and / or the rotation speed of the inner drum is 1000-2000 rpm.

[0016] In these optional embodiments, the stirring device can achieve good mixing and crushing effects on the powder and binder in the inner cylinder, and a vortex of sufficient strength can be formed between the inner cylinder and the outer cylinder to allow the particle structure to be fully rolled and polished in the vortex.

[0017] In some optional embodiments, the stirring device includes a stirring driving member and a shaft arranged at an output end of the stirring driving member, and the shaft is provided with at least one stirring paddle along its axial direction.

[0018] In these optional embodiments, the stirring device drives the shaft to rotate by means of a stirring drive, thereby driving the stirring paddles distributed axially along the shaft to break up and mix the powder and the binder and provide a cutting force capable of forming a particle structure and causing the particle structure to fly out of the first sieve hole.

[0019] In some optional embodiments, the stirring paddle includes at least two blades, and in the same stirring paddle, at least two blades are spaced apart and distributed along the circumference of the shaft.

[0020] In these optional embodiments, when the stirring paddle is driven by the shaft to rotate in the inner cylinder, the powder and the binder can be struck by one of the paddles and then by the other paddle, thereby reducing the time interval between the force applied to the powder and the binder and improving the crushing effect of the stirring device.

[0021] In some optional embodiments, in the same stirring paddle, at least two blades are spaced apart from each other along the axial direction of the shaft.

[0022] In these optional embodiments, at least two paddles located at different heights of the shaft can apply force to the powder and binder at different depths in the inner barrel to improve the uniformity of mixing.

[0023] In some optional embodiments, the blade includes a first portion and a second portion which are arranged along the radial direction of the shaft, the second portion is connected to the shaft through the first portion, and the thickness of the second portion is smaller than the thickness of the first portion.

[0024] In these optional embodiments, the second part with a smaller thickness can have a better cutting effect on the powder and the binder to obtain a particle structure with a smaller particle size, so that the particle structure is more likely to meet the particle size requirement, that is, smaller than the aperture of the first sieve hole; at the same time, the second part is located on the side of the stirring device closer to the wall of the inner cylinder to make it easier for the particle structure to fly out of the inner cylinder and enter the circulation channel.

[0025] In some optional embodiments, the second portion is disposed on the upper side of the first portion, and an extension direction of the second portion forms an obtuse angle with an extension direction of the first portion.

[0026] In these optional embodiments, during the rotation of the stirring device, the particle structure formed by the second cutting has an upward movement tendency and is more likely to fly out of the inner cylinder through the first screening holes and enter the circulation channel.

[0027] In some optional embodiments, the outer cylinder includes a top wall, and the top wall is provided with a plurality of second sieve holes communicating with the flow channel.

[0028] In these optional embodiments, the second screening hole can cooperate with the suspension force supply device to form secondary screening. For some particle structures with too small particle size, the suspension force is greater than its own weight, so that the particle structure has a tendency to move upward under the action of the suspension force and flows from the second screening hole to the outside of the outer cylinder without participating in subsequent processing steps.

[0029] In some optional embodiments, the aperture of the second sieve hole is smaller than the aperture of the first sieve hole, or the aperture of the second sieve hole is equal to the aperture of the first sieve hole.

[0030] In these optional embodiments, adjusting the aperture of the second sieve hole can adjust the uniformity of the final particle structure, which helps to obtain raw materials for electrode production with expected fluidity.

[0031] In some optional embodiments, the levitation force supply device includes at least one of a fan and a negative pressure pump to form an upward airflow in the circulation channel to provide levitation force, and the temperature of the upward airflow is lower than or equal to 10°C, wherein the fan is arranged at the bottom of the outer cylinder, and the negative pressure pump is arranged at the top of the outer cylinder.

[0032] In these optional embodiments, controlling the temperature of the rising airflow can adjust the effectiveness or viscosity of the binder located at the outer edge of the particle structure, thereby reducing the probability of the particle structure agglomerating or agglomerating in the rising airflow. The fan or negative pressure pump can form an rising airflow that flows from the bottom of the outer cylinder toward the top of the outer cylinder and can provide a suspension force for the particle structure, so that the particle structure will not fall to the bottom of the outer cylinder under its own weight.

[0033] In some optional embodiments, the temperature of the rising air flow is 0°C.

[0034] In these optional embodiments, the particle structure can roll efficiently and randomly in the flow channel while being free from aggregation and agglomeration under the action of the binder.

[0035] In some optional embodiments, the powder granulation mechanism further includes a collecting device, which is communicated with the flow channel and is disposed at the bottom end of the outer cylinder, and is used to collect the particle structure that falls due to its own weight.

[0036] In these optional embodiments, the powder granulation mechanism can periodically collect the particle structure in the flow channel by controlling the opening and closing of the suspension force supply device.

[0037] In a second aspect, an embodiment of the present application provides a pole piece production system, and the pole piece production system includes the powder granulation mechanism provided by any embodiment of the aforementioned first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic structural diagram of a powder granulation mechanism according to an embodiment of the present application;

[0040] Figure 2 This is a schematic structural diagram of a powder granulation mechanism according to another embodiment of the present application;

[0041] Figure 3 This is a schematic structural diagram of a powder granulation mechanism according to another embodiment of the present application;

[0042] Figure 4 This is a schematic structural diagram of a powder granulation mechanism according to another embodiment of the present application;

[0043] Figure 5 This is a schematic structural diagram of a powder granulation mechanism according to another embodiment of the present application.

[0044] In the drawings, the drawings are not necessarily drawn to scale.

[0045] The specific reference numerals involved in the drawings are as follows:

[0046] 110, inner cylinder; 111, first sieve hole; 112, inner cylinder driving member; 120, outer cylinder; 121, top wall; 1211, second sieve hole; 130, circulation channel;

[0047] 200, stirring device; 210, shaft; 220, stirring paddle; 221, paddle; 2211, first part; 2212, second part; 2213, third part; 230, stirring drive member;

[0048] 300. Suspension force supply device; 400. Collection device. DETAILED DESCRIPTION

[0049] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0051] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0054] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0055] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0056] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0057] Battery cells, such as lithium-ion battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells or magnesium-ion battery cells, have the advantages of high energy density, high power density, many cycles, long storage time, etc., and have been widely used in electrical devices suitable for battery cells. For example, electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.; spacecraft include airplanes, rockets, space shuttles and spacecrafts, etc.; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc.

[0058] The battery cell includes an electrode assembly for electrochemical reaction, which is mainly composed of a positive electrode sheet and a negative electrode sheet wound or stacked. The manufacturing of the electrode sheet is mainly divided into wet technology and dry technology. Among them, the dry technology has the advantages of high compaction density and high production efficiency. However, the dry technology still has the defect of difficult quality control.

[0059] During the dry preparation process, active materials and other powders are bonded by a binder to form a particle structure, which is then fed to a roller press mechanism to form a sheet structure, such as a membrane. However, the particle structure is prone to agglomeration under the action of the binder, resulting in differences in feed density at the feed point of the roller press mechanism, which in turn results in the final pole sheet having a defect of different density, affecting the performance of the battery.

[0060] In the related art, in order to avoid agglomeration of the particle structure under the action of the binder, some equipment adopts screening to ensure that the particle size of the raw materials entering the rolling mechanism meets the production requirements. However, the vibration and friction during the screening process will cause irreversible damage to the binder fibers in the particle structure, greatly affecting the strength of the membrane after rolling, and even causing the membrane to be unable to withstand the rolling strength and rupture.

[0061] In addition, although the screening operation can control the particle size of the raw materials entering the roller pressing mechanism, it cannot achieve the effect of shape screening or shaping, and has no effect on improving the fluidity of the incoming materials to the roller pressing mechanism.

[0062] In view of the above problems, the embodiment of the present application provides a powder granulation mechanism, which can shape the particle structure while preparing a particle structure that meets the particle size requirements, improve the sphericity of the particle structure to enhance the fluidity of the material coming from the roller pressing mechanism. At the same time, the powder granulation mechanism can also temporarily store the particle structures in a dispersed manner to reduce the possible agglomeration between the particle structures, thereby improving the problem of uneven density in the electrode product.

[0063] The technical solution described in the embodiment of the present application is not only applicable to a powder granulation mechanism, but also to a pole piece production system including a powder granulation mechanism.

[0064] See also Figure 1 In the first aspect, the embodiment of the present application provides a powder granulation mechanism, which includes an inner cylinder 110, an outer cylinder 120, a suspension force supply device 300 and a stirring device 200 arranged on the inner cylinder 110. The inner cylinder 110 is used to accommodate powder and binder. The inner cylinder 110 and the outer cylinder 120 are spaced apart from each other in their own radial direction and form a circulation channel 130. A plurality of first sieve holes 111 are penetrated through the wall of the inner cylinder 110. The suspension force supply device 300 is connected to the circulation channel 130; wherein the suspension force supply device 300 can provide suspension force to the circulation channel 130.

[0065] The powder material refers to the powdered raw material used to produce the substrate or membrane of the electrode, including at least one of the active material and the conductive agent. These powdered raw materials and the binder form a mixture under the action of the stirring device 200. After the mixture is crushed by the stirring device 200 to form a particle structure, the particle structure with a particle size smaller than the aperture size of the first sieve hole 111 can fly out of the inner cylinder 110 and be rolled and ground in the circulation channel 130.

[0066] The inner cylinder 110 and the outer cylinder 120 are mutually nested, which means that the outer cylinder 120 is arranged on the outer side of the inner cylinder 110 along the radial direction of the inner cylinder 110, wherein the inner cylinder 110 and the outer cylinder 120 can be arranged in contact, or the inner cylinder 110 and the outer cylinder 120 are arranged at intervals. In the embodiment of the present application, the inner cylinder 110 and the outer cylinder 120 are arranged at intervals in their own radial direction, which means that the inner cylinder 110 is spaced from the outer cylinder 120 in at least one radial direction of itself, or the outer cylinder 120 is spaced from the inner cylinder 110 in at least one radial direction of itself. That is, the circulation channel 130 can be arranged around the outer circumference of the entire inner cylinder 110, or the circulation channel 130 is arranged only corresponding to a part of the outer circumference of the inner cylinder 110.

[0067] The levitation force supply device 300 is a device that can provide levitation force that can be used to overcome the self-weight of the particle structure that flies out of the inner tube 110. The levitation force supply device 300 can provide buoyancy to the particle structure in the form of output airflow, or, when the particle structure is magnetic, the levitation force supply device 300 can provide magnetic force to enable the particle structure to overcome its own weight and achieve suspension.

[0068] The two ends of the circulation channel 130 are respectively connected to the bottom and the top of the outer cylinder 120, so that the circulation channel 130 can maintain a stable pressure during the operation of the powder granulation mechanism, thereby reducing the rotating airflow during the rotation of the stirring device 200 from being output to the circulation channel 130 through the first sieve hole 111 and affecting the movement direction of the particle structure.

[0069] The powder granulation mechanism provided in the embodiment of the present application is provided with a stirring device 200 in the inner cylinder 110. The stirring device 200 can mix the powder and the binder in the inner cylinder 110 and cut them into a particle structure. The shear force provided by the stirring device 200 to the binder can realize the fiberization of the binder so that the particle structure forms a block or flocculent pre-fiberized product to improve the compaction density and structural stability of the pole piece. The particle structure with a particle size smaller than the aperture size of the first sieve hole 111 can fly out of the inner cylinder 110 from the first sieve hole 111 and enter the circulation channel 130 to reduce the agglomeration phenomenon that may occur between the particle structures. After the particle structure enters the circulation channel 130, since the particle structure has a linear velocity when it flies out, and the suspension force supply device 300 can provide suspension force to the particle structure to offset the deadweight of the particle structure, the particle structure can roll in the circulation channel 130 to improve its own sphericity, improve the fluidity of the pole piece production material, and improve the quality of subsequent processes.

[0070] See also Figure 2 According to some embodiments of the present application, the inner cylinder 110 and the outer cylinder 120 are coaxially arranged, and the inner cylinder 110 and the outer cylinder 120 are relatively rotatably arranged.

[0071] Optionally, the inner cylinder 110 and the outer cylinder 120 are flush with each other at one end in the height direction, for example, the top ends of the inner cylinder 110 and the outer cylinder 120 are flush with each other, or the bottom ends of the inner cylinder 110 and the outer cylinder 120 are flush with each other.

[0072] Optionally, the top and bottom ends of the outer cylinder 120 are both arranged beyond the inner cylinder 110, that is, the entire inner cylinder 110 is arranged inside the cylinder body of the outer cylinder 120. Such a setting can reduce the situation where the particle structure flies out of the inner cylinder 110 from the first screening hole 111 and is separated from the outer cylinder 120 without being fully ground in the circulation channel 130.

[0073] It can be understood that the inner cylinder 110 and the outer cylinder 120 are relatively rotatably arranged, including that the inner cylinder 110 can rotate and the outer cylinder 120 is fixed, or the outer cylinder 120 can rotate and the inner cylinder 110 is fixed, or the inner cylinder 110 and the outer cylinder 120 can both rotate but the rotation speeds of the two are inconsistent.

[0074] Therefore, on a horizontal plane at the same height, the width of the circulation channel 130 in any radial direction of the inner cylinder 110 is the same, the circulation channel 130 formed by the inner cylinder 110 and the outer cylinder 120 is uniform in shape, and the suspension force provided to the particle structure at each location of the circulation channel 130 tends to be the same. The relative rotation that can occur between the inner cylinder 110 and the outer cylinder 120 can cooperate with the suspension force supply device 300 to form a vortex, improve the disorder of the rolling motion of the particle structure in the circulation channel 130, further improve the sphericity of the particle structure and accelerate the shaping of the particle structure.

[0075] Please continue reading Figure 2 According to some embodiments of the present application, the stirring device 200 is coaxially arranged with the inner cylinder 110 , the inner cylinder 110 is rotatably disposed in the outer cylinder 120 , and the rotation speed of the inner cylinder 110 is lower than the rotation speed of the stirring device 200 .

[0076] Optionally, the powder granulation mechanism includes an inner cylinder driving member 112, and the inner cylinder driving member 112 and the stirring device 200 are arranged on the same side of the inner cylinder 110 along the height direction, or the inner cylinder driving member 112 and the stirring device 200 are arranged on both sides of the inner cylinder 110 along the height direction. Figure 3 The inner cylinder driving member 112 is arranged at the bottom end of the inner cylinder 110 , and the stirring device 200 is arranged at the top end of the inner cylinder 110 .

[0077] It can be understood that the rotation speed of the inner drum 110 is lower than the rotation speed of the stirring device 200 so that the rotation speed of the stirring device 200 is higher than the rotation speed of the powder and the binder to form a mixing and crushing effect to generate a particle structure.

[0078] As a result, the probability of the particle structure crushed by the stirring device 200 flying out of the first sieve holes 111 on the wall of the inner cylinder 110 tends to be the same, reducing the probability of the particle structure gathering in a certain area in the flow channel 130. The rotation speed of the stirring device 200 is higher than that of the inner cylinder 110 to achieve the effect of stirring, mixing and cutting and crushing the powder and the binder.

[0079] According to some embodiments of the present application, the difference between the rotation speed of the stirring device 200 and the rotation speed of the inner drum 110 is greater than or equal to 2000 rpm.

[0080] It is understandable that, as the speed difference between the stirring device 200 and the inner cylinder 110 decreases, the stirring device 200's mixing effect on the mixture of powder and binder is weakened, and the density uniformity of the particle structure formed by cutting is reduced. In other words, the speed of the stirring device 200 relative to the mixture of powder and binder in the inner cylinder 110 is at least 2000 rpm to form a good mixing and crushing effect, thereby improving the structural strength of the pole piece.

[0081] Therefore, there is a sufficient rotation speed difference between the stirring device 200 and the inner cylinder 110 to break the powder and the binder into a particle structure with a particle size smaller than the aperture size of the first sieve hole 111 .

[0082] According to some embodiments of the present application, the difference between the rotation speed of the stirring device 200 and the rotation speed of the inner drum 110 is less than or equal to 3000 rpm.

[0083] It is understood that as the speed difference between the stirring device 200 and the inner cylinder 110 increases, the cutting effect of the stirring device 200 on the mixture of the powder and the binder is enhanced, and the particle size of the particle structure formed by cutting is reduced. In other words, the speed of the stirring device 200 relative to the mixture of the powder and the binder in the inner cylinder 110 is at most 3000 rpm to control the particle size of the particle structure and to fiberize the binder.

[0084] Therefore, the speed difference between the stirring device 200 and the inner drum 110 is within a reasonable range to prevent the particle size of the particle structure from being too small and causing negative impact on subsequent processes.

[0085] According to some embodiments of the present application, the rotation speed of the stirring device 200 is 3000-5000 rpm, and the stirring device 200 can take into account both the mixing effect and the crushing effect on the mixture of the powder and the binder.

[0086] It can be understood that, according to other embodiments of the present application, the rotation speed of the stirring device 200 can be appropriately adjusted according to the ratio, material, total amount, etc. of the powder and the binder.

[0087] According to some embodiments of the present application, the rotation speed of the inner cylinder 110 is 1000-2000 rpm, and a vortex of sufficient strength can be formed between the inner cylinder 110 and the outer cylinder 120 to allow the particle structure to fully roll and grind in the vortex.

[0088] It can be understood that, according to other embodiments of the present application, the rotation speed of the inner drum 110 can be appropriately adjusted according to the particle size, weight, etc. of the particle structure.

[0089] See also Figure 2According to some embodiments of the present application, the stirring device 200 includes a stirring driving member 230 and a shaft 210 disposed at an output end of the stirring driving member 230 , and the shaft 210 is provided with at least one stirring paddle 220 along its axial direction.

[0090] Optionally, the contact surface between the stirring paddle 220 and the mixture of powder and binder forms an angle greater than 0 and less than 90° with the horizontal plane. The smaller the angle, the better the cutting effect of the stirring paddle 220 on the mixture, and the worse the contact area and mixing effect of the mixture; the larger the angle, the weaker the cutting effect of the stirring paddle 220 on the mixture, and the better the contact area and mixing effect of the mixture.

[0091] Further optionally, the angle between the contact surface of the stirring paddle 220 and the mixture of powder and binder and the horizontal plane is one of 15°, 22.5°, 30°, 37.5°, 45°, 52.5°, 60°, 67.5°, 75°, and 82.5°.

[0092] Thus, the stirring device 200 drives the shaft 210 to rotate through the stirring driving member 230, thereby driving the stirring paddle 220 distributed axially along the shaft 210 to break up and mix the powder and the binder and provide a cutting force that can form a particle structure and make the particle structure fly out of the first sieve hole 111.

[0093] See also Figure 2 and Figure 3 According to some embodiments of the present application, the stirring paddle 220 includes at least two blades 221 , and in the same stirring paddle 220 , at least two blades 221 are distributed at intervals along the circumference of the shaft 210 .

[0094] Optionally, at least two blades 221 are evenly distributed along the circumference of the shaft 210. Exemplarily, the stirring paddle 220 includes two blades 221, which are arranged 180° apart, or the stirring paddle 220 includes three blades 221, and two adjacent blades 221 are arranged 120° apart.

[0095] Therefore, when the stirring paddle 220 is driven by the shaft 210 to rotate in the inner cylinder 110, the powder and the binder can be hit by one of the paddles 221 and then by the other paddle 221, thereby reducing the time interval between the powder and the binder being subjected to force and improving the mixing and crushing effects of the stirring device 200.

[0096] See also Figure 2 According to some embodiments of the present application, in the same stirring paddle 220 , at least two blades 221 are distributed at intervals along the axial direction of the shaft 210 .

[0097] Optionally, the distances between any two axially adjacent blades 221 along the shaft 210 are equal.

[0098] Optionally, the distance between two adjacent blades 221 near the bottom of the inner cylinder 110 is smaller than the distance between two adjacent blades 221 away from the bottom of the inner cylinder 110, so as to enhance the mixing effect of the stirring device 200 on the powder and binder accumulated at the bottom of the inner cylinder 110, so that the density of the mixture at different depths of the inner cylinder 110 tends to be the same.

[0099] Thus, at least two blades 221 located at different heights of the shaft 210 can exert force on the powder and the binder at different depths in the inner cylinder 110 to improve the mixing uniformity.

[0100] See also Figure 3 According to some embodiments of the present application, the blade 221 includes a first portion 2211 and a second portion 2212 arranged along the radial direction of the shaft 210, the second portion 2212 is connected to the shaft 210 through the first portion 2211, and the thickness of the second portion 2212 is less than the thickness of the first portion 2211.

[0101] Optionally, the angle between the second portion 2212 and the vertical plane is set to be the same as the angle between the first portion 2211 and the vertical plane.

[0102] Optionally, the angle between the second portion 2212 and the vertical plane is set differently from the angle between the first portion 2211 and the vertical plane. Exemplarily, the second portion 2212 and the first portion 2211 are set in a spiral shape, so that the mixture of the powder and the binder can be driven to roll along the extension direction of the blade 221 when in contact with the blade 221, that is, the mixture is mixed along the circumferential direction of the inner cylinder 110 while also being mixed in the radial direction of the inner cylinder 110, further improving the degree of mixing.

[0103] Thus, the second portion 2212 with a smaller thickness can be used as a blade portion, thereby achieving a better cutting effect on the powder and the binder, obtaining a particle structure with a smaller particle size, providing a better fiberization effect on the binder, and making the particle structure more likely to meet the particle size requirement, that is, smaller than the aperture of the first sieve hole 111; at the same time, the second portion 2212 is located on the side of the stirring device 200 that is closer to the wall of the inner cylinder 110 so that the particle structure has a higher radial movement speed, and the particle structure is more likely to fly out of the inner cylinder 110 and enter the circulation channel 130.

[0104] According to some embodiments of the present application, the second portion 2212 is disposed on the upper side of the first portion 2211 , and an extension direction of the second portion 2212 forms an obtuse angle with an extension direction of the first portion 2211 .

[0105] Optionally, an extension direction of the second portion 2212 is one of 105°, 120°, 135°, 150°, and 165° with an extension direction of the first portion 2211 .

[0106] Optionally, see Figure 4 A third portion 2213 is further provided between the first portion 2211 and the second portion 2212. The angle between the third portion 2213 and the horizontal plane is greater than the angle between the first portion 2211 and the horizontal plane and is smaller than the angle between the second portion 2212 and the horizontal plane, so as to realize the transition between the first portion 2211 and the second portion 2212 so that the mixture of powder and binder can flow more smoothly between the first portion 2211 and the second portion 2212.

[0107] Therefore, during the rotation of the stirring device 200 , the particle structure formed by cutting the second portion 2212 has an upward movement tendency and is more likely to fly out of the inner cylinder 110 through the first sieve holes 111 and enter the circulation channel 130 .

[0108] See also Figure 5 According to some embodiments of the present application, the outer cylinder 120 includes a top wall 121 , and the top wall 121 is provided with a plurality of second sieve holes 1211 .

[0109] Therefore, the second screening hole 1211 can cooperate with the suspension force supply device 300 to form a secondary screening. For some particle structures with too small particle size, the suspension force is greater than its own weight, so that the particle structure has a tendency to move upward under the action of the suspension force and flows from the second screening hole 1211 to the outside of the outer cylinder 120 without participating in subsequent processing steps.

[0110] According to some embodiments of the present application, the aperture of the second sieve hole 1211 is smaller than the aperture of the first sieve hole 111 , or the aperture of the second sieve hole 1211 is equal to the aperture of the first sieve hole 111 .

[0111] Therefore, the particle size of the remaining particle structure in the circulation channel 130 is less than or equal to the aperture of the first sieve hole 111 and greater than or equal to the aperture of the second sieve hole 1211. Adjusting the aperture of the second sieve hole 1211 can adjust the uniformity of the final particle structure, which helps to obtain electrode production raw materials with expected fluidity.

[0112] According to some embodiments of the present application, the levitation force supply device 300 includes a fan, which is disposed at the bottom of the outer cylinder 120 and outputs an ascending airflow to the circulation channel 130 to provide levitation force, and the temperature of the ascending airflow is lower than or equal to 10°C.

[0113] According to some embodiments of the present application, the suspension force supply device 300 includes a negative pressure pump or other equipment that can make the particle structure approach the suspension force supply device 300. The suspension force supply device 300 is arranged at the top of the outer cylinder 120 to form an upward airflow and provide suspension force to the particle structure to overcome its own weight, so that the particle structure can be suspended and stay in the circulation channel 130 for rolling grinding. The temperature of the upward airflow is less than or equal to 10°C.

[0114] Thus, the suspension force supply device can form an ascending airflow by blowing air toward the top of the outer cylinder 120 through a fan or sucking air from the bottom of the outer cylinder 120 through a negative pressure pump. The ascending airflow flows from the bottom of the outer cylinder 120 to the top of the outer cylinder 120 and can provide a suspension force to the particle structure, so that the particle structure will not fall to the bottom of the outer cylinder 120 under the action of its own weight. Controlling the temperature of the ascending airflow can adjust the effectiveness or viscosity of the binder at the outer edge of the particle structure, thereby reducing the probability of the particle structure agglomerating and agglomerating in the ascending airflow.

[0115] It can be understood that according to other embodiments of the present application, the temperature of the rising air flow can be adjusted according to the material and physical properties of the binder, but it is necessary to make the temperature range of the rising air flow at least partially outside the effective temperature of the binder so as to reduce the adhesion of the binder exposed to the outer edge of the particle structure, thereby reducing the aggregation of the particle structure during the disordered rolling process in the circulation channel 130.

[0116] According to some embodiments of the present application, the temperature of the rising air flow is 0°C.

[0117] It can be understood that as the temperature of the rising air flow decreases, the disorder of the particle structure moving inside the vortex becomes lower, and the shaping effect of the vortex on the particle structure becomes weaker.

[0118] As a result, the particle structure can roll efficiently and disorderly in the flow channel 130 while being free from aggregation and agglomeration under the action of the binder.

[0119] According to some embodiments of the present application, the powder granulation mechanism further includes a collecting device 400 , which is connected to the circulation channel 130 and is disposed at the bottom end of the outer cylinder 120 , and is used to collect the particle structure that falls due to its own weight.

[0120] Optionally, the collecting device 400 includes at least one detachable storage bin to facilitate batch transfer of the particle structure in the storage bin to the rolling mechanism.

[0121] Optionally, the collecting device 400 is directly connected to the feeding area of ​​the roller pressing mechanism to achieve continuous supply from the granulation process to the roller pressing process.

[0122] Therefore, by controlling the opening and closing of the suspension force supply device 300 to collect the particle structure completed by rolling grinding in the flow channel 130, the aggregation of the particle structure due to long-term accumulation can be reduced, which helps to improve the problem of poor structural strength caused by uneven density of the pole piece after rolling.

[0123] See also Figure 4 The embodiment of the present application provides a powder granulation mechanism, including an inner cylinder 110 and a stirring device 200 disposed in the inner cylinder 110, wherein the inner cylinder 110 is used to contain powder and binder, and a first sieve hole 111 is provided on the wall of the inner cylinder 110. The stirring device 200 can stir and mix the mixture of the powder and the binder and provide a shear force that can fiberize the binder to promote the mixing of the powder and the binder. At the same time, the shear force provided by the stirring device 200 can form a crushing effect on the mixture to form a particle structure, and the particle structure with a particle size smaller than the aperture of the first sieve hole 111 can be separated from the inner cylinder 110 from the first sieve hole 111.

[0124] The powder granulation mechanism also has an outer cylinder 120 coaxially sleeved outside the inner cylinder 110, and a circulation channel 130 is sandwiched between the inner cylinder 110 and the outer cylinder 120. A fan connected to the circulation channel 130 is also provided at the bottom of the outer cylinder 120, and the fan outputs airflow to the circulation channel 130 to provide buoyancy that can enable the particle structure to overcome its own weight, and the particle structure flying out of the first screening hole 111 is suspended and temporarily stored in the circulation channel 130. Since the particle structure has a radial linear velocity when flying out, the particle structure can continue to roll while suspended in the circulation channel 130, and the airflow can continuously apply force during the rolling process of the particle structure to form a grinding effect, thereby improving the sphericity of the particle structure.

[0125] The powder granulation mechanism is also provided with an inner cylinder driving member 112 for driving the inner cylinder 110 to rotate. The inner cylinder 110 rotates relative to the outer cylinder 120 and cooperates with the fan to form a vortex in the circulation channel 130. The vortex can provide buoyancy to the particle structure to overcome its own weight while providing a horizontal force that causes the particle structure to roll, thereby accelerating the shaping of the particle structure in the circulation channel 130.

[0126] When the particle structure needs to be collected, the fan is turned off to stop providing buoyancy to the particle structure, and the particle structure in the circulation channel 130 can fall under the influence of its own weight and be separated from the bottom end of the outer cylinder 120 for collection.

[0127] In the second aspect, an embodiment of the present application provides a pole piece production system, which includes the powder granulation mechanism provided by any of the aforementioned embodiments, so the pole piece production system has all the beneficial effects of the aforementioned powder granulation mechanism.

[0128] Optionally, the electrode production system also includes a rolling mechanism, which is used to receive the particle structure produced by the powder granulation mechanism and rolled and ground in the circulation channel 130. The particle structure has good fluidity and high density uniformity, so that the rolling mechanism can obtain a membrane with good structural strength through rolling molding, thereby improving the performance of the electrode and the battery.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A powder granulation mechanism, characterized in that: The invention comprises an inner cylinder, an outer cylinder, a suspension force supply device and a stirring device arranged on the inner cylinder, wherein the inner cylinder is used to contain powder and a binder, the inner cylinder and the outer cylinder are arranged at intervals from each other in their radial direction and form a flow channel, a wall of the inner cylinder is penetrated with a plurality of first sieve holes, and the suspension force supply device is connected with the flow channel; Wherein, the suspension force supply device can provide suspension force to the circulation channel.

2. The powder granulation mechanism according to claim 1, characterized in that: The inner cylinder and the outer cylinder are coaxially arranged, and the inner cylinder and the outer cylinder are relatively rotatable.

3. The powder granulation mechanism according to claim 2, characterized in that: The stirring device is coaxially arranged with the inner cylinder, the inner cylinder is rotatably arranged on the outer cylinder, and the rotation speed of the inner cylinder is lower than the rotation speed of the stirring device.

4. The powder granulation mechanism according to claim 3, characterized in that: The difference between the rotation speed of the stirring device and the rotation speed of the inner drum is greater than or equal to 2000 rpm.

5. The powder granulation mechanism according to claim 4, characterized in that: The difference between the rotation speed of the stirring device and the rotation speed of the inner cylinder is less than or equal to 3000 rpm.

6. The powder granulation mechanism according to claim 5, characterized in that: The rotation speed of the stirring device is 3000-5000 rpm, and / or the rotation speed of the inner cylinder is 1000-2000 rpm.

7. The powder granulation mechanism according to claim 1, characterized in that: The stirring device comprises a stirring driving member and a shaft arranged at the output end of the stirring driving member, and the shaft is provided with at least one stirring paddle along its axial direction.

8. The powder granulation mechanism according to claim 7, characterized in that: The stirring paddle includes at least two blades, and in the same stirring paddle, at least two blades are distributed at intervals along the circumference of the shaft.

9. The powder granulation mechanism according to claim 8, characterized in that: In the same stirring paddle, at least two blades are spaced apart from each other along the axial direction of the shaft.

10. The powder granulation mechanism according to claim 8, characterized in that: The blade includes a first portion and a second portion which are arranged along the radial direction of the shaft, the second portion is connected to the shaft through the first portion, and the thickness of the second portion is smaller than the thickness of the first portion.

11. The powder granulation mechanism according to claim 10, characterized in that: The second portion is disposed on the upper side of the first portion, and an extending direction of the second portion forms an obtuse angle with an extending direction of the first portion.

12. The powder granulation mechanism according to claim 1, characterized in that: The outer cylinder comprises a top wall, and the top wall is provided with a plurality of second sieve holes communicating with the flow channel.

13. The powder granulation mechanism according to claim 12, characterized in that: The aperture of the second sieve hole is smaller than the aperture of the first sieve hole, or the aperture of the second sieve hole is equal to the aperture of the first sieve hole.

14. The powder granulation mechanism according to claim 1, characterized in that: The levitation force supply device includes at least one of a fan and a negative pressure pump to form an upward airflow in the circulation channel to provide levitation force, and the temperature of the upward airflow is lower than or equal to 10°C, wherein the fan is arranged at the bottom of the outer tube, and the negative pressure pump is arranged at the top of the outer tube.

15. The powder granulation mechanism according to claim 14, characterized in that: The temperature of the rising air flow is 0°C.

16. The powder granulation mechanism according to claim 1, characterized in that: The powder granulation mechanism further comprises a collecting device, which is communicated with the circulation channel and is arranged at the bottom end of the outer cylinder, and is used for collecting the particle structure that falls due to its own weight.

17. A pole piece production system, characterized in that: It comprises a powder granulating mechanism as described in any one of claims 1 to 16.

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