A granulating device for a battery negative electrode material and a process thereof

Abstract

This invention provides a granulation device and process for battery negative electrode materials, relating to the field of granulation technology. The granulation device for battery negative electrode materials includes an inner shell and an outer shell. The highest position of the mixture inside the inner shell rises, and a moving ring and an inner protrusion move synchronously from bottom to top. The position of the inner protrusion matches the highest position of the mixture inside the inner shell, guiding the mixture towards the center of the inner shell and preventing it from adhering to the inner wall of the inner shell and further accumulating to form scale and evolve into a stagnant zone. When the agitator stops, the moving ring and the inner protrusion move from top to bottom, causing the mixture still adhering to the inner wall of the inner shell to peel off and be cleaned, reducing cleaning difficulty and downtime, and ensuring the continuity and stability of production. The mixture in the stagnant zone and the peeled-off mixture can continue to participate in the cyclic mixing and coating of the system, ensuring mixing uniformity and coating consistency, avoiding impact on the battery's rate performance, cycle stability, and material yield.

Description

Technical Field

[0001] This invention relates to the field of granulation technology, and in particular to a granulation device and process for battery negative electrode materials. Background Technology

[0002] In battery production, granulation is one of the core processes in the production of artificial graphite anode materials. It directly determines the particle size, distribution, and morphology of the anode material, thereby affecting key indicators such as rate performance, compaction density, and cycle life of the battery. Existing granulation processes are mainly divided into primary granulation and secondary granulation. Primary granulation involves pulverizing the raw coke into micron-sized fine powder using an air jet mill and then initially mixing it. Secondary granulation involves using high-temperature pyrolysis to bind the fine particles into composite particles of the target particle size. The core equipment for secondary granulation consists of a high-temperature coating granulation kettle and a rotary kiln. Among them, the vertical high-temperature coating granulation kettle is the most widely used. This equipment has a vertical closed structure, and the kettle body is equipped with a heating jacket and filled with a heat-conducting medium to achieve precise temperature control. It is equipped with a variable frequency speed-regulating stirring system inside, which can adopt paddle or turbine stirring forms. During operation, under the protective atmosphere of inert gases such as nitrogen, the industry mainstream adopts the method of simultaneous spray feeding of graphite micro powder and carbon-based binder. The dry graphite micro powder and liquid carbon-based binder are simultaneously atomized and sprayed into the kettle through dual atomizing nozzles, so that the two can collide and mix rapidly in the gas phase to improve coating uniformity and production efficiency. Then, the coating carbonization and granulation process is completed according to the preset temperature curve. At the same time, a tail gas treatment system is provided to collect the volatile gases generated by pyrolysis.

[0003] However, the above-mentioned coating granulation process has certain defects in actual production: the centrifugal force generated by the rotation of the agitator will drive the material in the reactor to move outward and rise along the reactor wall, forming a slow flow zone on the upper part of the reactor wall where the agitator cannot effectively scrape. The incompletely coated wetted solid-liquid particles formed by the collision of graphite micro powder and carbon-based binder in the gas phase will enter this slow flow zone and cause adhesion. The adhered material will continue to accumulate to form scale and evolve into a stagnation zone. The material in this area cannot participate in the circulation mixing and coating of the system, which not only causes uneven product composition and poor coating consistency, affecting the rate performance and cycle stability of the battery, but also reduces the material yield, increases the difficulty of equipment cleaning and downtime, and restricts the continuity and stability of production.

[0004] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] Therefore, it is necessary to provide a granulation equipment and process for battery anode materials to address the problems existing in the current coating granulation process.

[0006] The above objectives are achieved through the following technical solutions: A granulation device for battery negative electrode material includes an inner shell and an outer shell, both vertical and nested together, with a jacketed cavity formed between the inner and outer shells, filled with a heat-conducting medium. Graphite micropowder and a carbon-based binder simultaneously enter the inner shell from the top in an atomized form. A stirring element is provided at the bottom of the inner shell to stir the graphite micropowder and carbon-based binder and form a mixture. The inner shell is made of an elastic material, and a moving ring is provided outside the inner shell to deform the inner shell and form an inwardly convex portion. The moving ring has a first state and a second state. In the first state, the stirring element is activated, and the moving ring moves from bottom to top, causing the inwardly convex portion to move from bottom to top, and the position of the inwardly convex portion matches the highest position of the mixture in the inner shell. In the second state, the stirring element is stopped, and the moving ring moves from top to bottom, causing the inwardly convex portion to move from top to bottom.

[0007] Furthermore, the inner wall of the moving ring has two contact portions spaced vertically apart. These contact portions contact the outer wall of the inner shell and generate suction on it, so that the inner shell forms an inner convex portion between the two contact portions.

[0008] Furthermore, a side cavity is formed between the inner protrusion and the moving ring. The side cavity is equipped with a first pump body, which is used to pump a heat-conducting medium into the side cavity. The side cavity has a first through hole that communicates with the jacket cavity, and the heat-conducting medium in the side cavity can be discharged to the jacket cavity through the first through hole.

[0009] Furthermore, when the first pump body pumps the heat-conducting medium into the side cavity, it has an inflow rate, and when the heat-conducting medium in the side cavity is discharged to the jacket cavity through the first through hole, it has an outflow rate. When the inner convex part moves from top to bottom, the inflow rate is greater than the outflow rate, causing the inner convex part to gradually increase in size.

[0010] Furthermore, as the inner convex portion moves from top to bottom, the pumped flow rate alternately increases and decreases, causing the inner convex portion to gradually increase intermittently.

[0011] Furthermore, the movable ring is provided with a conduit, and the first through hole is connected to the jacket cavity through the conduit, with the end of the conduit facing upward.

[0012] Furthermore, the end of the catheter is positioned obliquely upwards.

[0013] Furthermore, the contact portion is an annular groove coaxial with the moving ring.

[0014] Furthermore, the inner wall of the inner shell is provided with a support ring coaxial with it, which is used to press the inner shell into the annular groove.

[0015] This invention also provides the following technical solutions: A granulation process for a battery negative electrode material includes the following steps: S01. Graphite powder and carbon-based binder enter the inner shell from the top in the form of atomization. The agitator is started to stir the graphite powder and carbon-based binder and form a mixture. The highest position of the mixture in the inner shell gradually rises, and the moving ring and the inner protrusion move synchronously from bottom to top. S02, the highest position of the mixture inside the inner shell stops rising, and the moving ring and inner protrusion remain stationary, while the agitator continues to start immediately; S03. When the agitator stops, the moving ring and the inner protrusion move synchronously from top to bottom, and then synchronously from bottom to top. S04. Repeat S02 and S03 a preset number of times; S05. Inert gas is introduced into the inner shell, and the temperature is raised to the pre-curing temperature using a heat-conducting medium and kept at that temperature to allow the carbon-based binder to undergo initial cross-linking. S06. Continue heating to the carbonization temperature and hold the temperature to allow the carbon-based binder to pyrolyze and transform into a binding carbon phase, thus completing the coating and granulation of graphite particles. S07. Cool to discharge temperature to obtain artificial graphite secondary granulation precursor.

[0016] The present invention has at least the following beneficial effects: Graphite powder and carbon-based binder are simultaneously atomized and enter the inner shell from the top. The agitator stirs the graphite powder and carbon-based binder to form a mixture, and the highest point of the mixture inside the inner shell gradually rises. Simultaneously, the moving ring moves from bottom to top, causing the inner convex portion to move from bottom to top, and the position of the inner convex portion matches the highest point of the mixture inside the inner shell. This guides the mixture towards the center of the inner shell, preventing it from adhering to the inner wall and further accumulating to form scale and a stagnant zone. When the highest point of the mixture inside the inner shell stops rising and remains so for a certain period, the agitator stops, and the moving ring moves from top to bottom, causing the inner convex portion to move from top to bottom. This causes the mixture still adhering to the inner wall of the inner shell to peel off and be cleaned, reducing cleaning difficulty and downtime, and ensuring production continuity and stability. The mixture in the stagnant zone and the peeled-off mixture can continue to participate in the system's cyclic mixing and coating, ensuring mixing uniformity and coating consistency to a certain extent, avoiding impact on the battery's rate performance, cycle stability, and material yield. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the granulation equipment for the battery negative electrode material provided in Embodiment 1 of the present invention; Figure 2 for Figure 1 Bottom view; Figure 3 for Figure 1 The front view; Figure 4 for Figure 3 Sectional view along axis AA; Figure 5 for Figure 4 A magnified view of a section at point B in the middle; Figure 6 for Figure 4 Schematic diagram of the moving ring structure; Figure 7 for Figure 6 Top view; Figure 8 for Figure 7 CC-direction sectional view; Figure 9 for Figure 8 A magnified view of a section at point D; Figure 10 for Figure 7 EE-directed sectional view; Figure 11 This is a schematic diagram of the structure of the granulation equipment for the battery negative electrode material provided in Embodiment 2 of the present invention; Figure 12 for Figure 11 FF section view; Figure 13 for Figure 12 A magnified view of a section at point G in the middle; Figure 14 for Figure 12 Schematic diagram of the moving ring structure; Figure 15 for Figure 14 HH-direction sectional view; Figure 16 for Figure 15 A magnified view of a section at point J; Figure 17 This is a schematic diagram of the granulation equipment for the battery negative electrode material provided in Embodiment 3 of the present invention; Figure 18 for Figure 17 A schematic diagram of the moving ring structure.

[0018] in: 101. Inner shell; 102. Outer shell; 103. Jacketed cavity; 104. Agitator; 105. Feed inlet; 106. First air inlet; 107. Liquid inlet; 108. Second air inlet; 109. First inlet; 110. Second inlet; 111. First outlet; 112. Observation window; 113. Insulation pipe; 114. Motor; 115. Discharge outlet; 201. Moving ring; 202. Inner protrusion; 203. First protective cover; 204. Telescopic cylinder; 205. Side hole; 206. Air passage; 207. Annular groove; 208. Support ring; 209. Side cavity; 210. First pump body; 211. First through hole; 212. Second through hole; 213. Conduit; 214. Second pump body; 215. Second protective cover. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used in this invention, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0022] Example 1 like Figures 1 to 10As shown, Embodiment 1 of the present invention provides a granulation device for battery negative electrode material, including an inner shell 101 and an outer shell 102, both vertical and nested together, with a jacket cavity 103 formed between the inner shell 101 and the outer shell 102, the jacket cavity 103 being filled with a heat-conducting medium; graphite micro powder and carbon-based binder simultaneously enter the inner shell 101 from the top in an atomized form; a stirring element 104 is provided at the bottom of the inner shell 101, the stirring element 104 being used to stir the graphite micro powder and carbon-based binder to form a mixture; the inner shell 101 is made of an elastic material, the inner shell 101... The outer shell is provided with a movable ring 201, which is used to deform the inner shell 101 and form an inwardly protruding inner convex part 202. The movable ring 201 has a first state and a second state. In the first state, the agitator 104 is started and the movable ring 201 moves from bottom to top, so that the inner convex part 202 moves from bottom to top and the position of the inner convex part 202 matches the highest position of the mixture inside the inner shell 101. In the second state, the agitator 104 is stopped and the movable ring 201 moves from top to bottom, so that the inner convex part 202 moves from top to bottom.

[0023] Graphite powder and carbon-based binder simultaneously enter the inner shell 101 from the top in an atomized form. The agitator 104 stirs the graphite powder and carbon-based binder to form a mixture, and the highest point of the mixture inside the inner shell 101 gradually rises. Simultaneously, the moving ring 201 moves from bottom to top, causing the inner protrusion 202 to move from bottom to top. The position of the inner protrusion 202 matches the highest point of the mixture inside the inner shell 101, guiding the mixture towards the center of the inner shell 101 and preventing it from adhering to the inner wall of the inner shell 101 and further accumulating to form scale and a stagnant zone. When the highest point of the mixture inside the inner shell 101 stops rising and remains so for a certain period, the agitator 104 stops, and the moving ring 201 moves from top to bottom, causing the inner protrusion 202 to move from top to bottom, causing the mixture still adhering to the inner wall of the inner shell 101 to peel off and be cleaned. This reduces cleaning difficulty and downtime, ensuring continuous and stable production. The mixture in the retention zone and the detached mixture can continue to participate in the system's cyclic mixing and coating, ensuring to a certain extent the uniformity of mixing and the consistency of coating, thus avoiding affecting the battery's rate performance, cycle stability, and material yield.

[0024] Among them, see Figure 1 and Figure 2The outer shell 102 has a feed inlet 105, a first air inlet 106, a liquid inlet 107, and a second air inlet 108 at its top. The feed inlet 105 is used to introduce graphite powder, and the first air inlet 106 is used to introduce compressed gas, causing the graphite powder to enter the inner shell 101 from the top in an atomized form. The liquid inlet 107 is used to introduce carbon-based binder, and the second air inlet 108 is used to introduce compressed gas, causing the carbon-based binder to also enter the inner shell 101 from the top in an atomized form, where it will collide and mix with the atomized graphite powder in the inner shell 101. The bottom of the outer shell 102 has a first inlet 109 and a second inlet 110. The first inlet 109 is used to introduce a heat-conducting medium into the jacket cavity 103, and the top of the outer shell 102 may have a first outlet 111 for discharging the heat-conducting medium, allowing the heat-conducting medium in the jacket cavity 103 to circulate. The second inlet 110 is used to introduce inert gas, such as nitrogen or argon, into the inner shell 101. The top of the outer shell 102 is also equipped with an observation window 112, lifting lugs, and a mounting bracket. Insulation pipes 113 are coiled around the side walls of the outer shell 102, and the insulation pipes 113 are filled with circulating insulation medium to insulate the heat-conducting medium in the jacket cavity 103. The bottom of the outer shell 102 is also equipped with a discharge port 115 for discharging materials. The specific structure, arrangement, and working principle of the relevant interfaces and components on the outer shell 102 are all existing technologies and will not be described in detail here.

[0025] In addition, the outer shell 102 can be made of stainless steel, carbon steel, or enamel, which have good corrosion resistance and strength. The inner shell 101 can be made of styrene-silicone rubber, which has a high melting point and excellent elasticity at high temperatures. The stirring element 104 can be a paddle or turbine type, preferably a paddle type, and a motor 114 is arranged on the top of the outer shell 102. The motor 114 is equipped with a corresponding power supply and control module to control start-stop and speed, etc., to adapt to different working conditions. The output end of the motor 114 extends to the bottom of the inner shell 101 and is fixed to the stirring element 104. The output end of the motor 114 drives the stirring element 104 to rotate, thereby stirring the mixture. The seal of the output end of the motor 114 adopts a special sanitary mechanical seal design to ensure that the mixture is not contaminated. An exhaust gas treatment system is also provided to collect and treat the volatile gases generated during pyrolysis. Multiple first protective covers 203 may be provided within the jacket cavity 103. Each first protective cover 203 is equipped with a telescopic cylinder 204. The telescopic cylinder 204 may be in the form of a pneumatic cylinder or a hydraulic cylinder, and is equipped with a corresponding power source and control module to control the start, stop, and telescopic stroke. The output end of the telescopic cylinder 204 extends and retracts vertically and is fixed to the moving ring 201 to drive the moving ring 201 to move vertically. See also... Figure 6 The moving ring 201 has multiple side holes 205 so that the jacket cavities 103 on the upper and lower sides of the moving ring 201 can be connected to each other.

[0026] It is worth noting that the upward moving speed of the moving ring 201 is less than its downward moving speed. The upward moving speed of the moving ring 201 depends on the rising speed of the highest position of the mixture inside the inner shell 101, and is therefore smaller. The downward moving speed of the moving ring 201 needs to be larger so that the mixture still adhering to the inner wall of the inner shell 101 can be quickly peeled off and cleaned, improving cleaning efficiency, further reducing downtime, and ensuring the continuity and stability of production.

[0027] Further, see Figure 5 and Figure 10 The inner wall of the moving ring 201 has two contact portions spaced vertically. The contact portions contact the outer wall of the inner shell 101 and generate suction on it, so that the inner shell 101 forms an inner protrusion 202 between the two contact portions.

[0028] An air passage 206 is formed within the moving ring 201. One end of the air passage 206 is connected to an external vacuum device, and the other end extends to a contact portion. When the contact portion contacts the outer wall of the inner shell 101, the external vacuum device creates a negative pressure within the air passage 206 and at the contact portion, generating suction on the corresponding position of the outer wall of the inner shell 101. This temporarily fixes the corresponding position of the outer wall of the inner shell 101, thereby forming an inner protrusion 202 between the two contact portions. The specific selection of the external vacuum device is not limited here. When the moving ring 201 moves up and down, the contact position between the outer wall of the inner shell 101 and the contact portion also changes accordingly, causing the inner protrusion 202 to move up and down synchronously.

[0029] Furthermore, the contact portion is an annular groove 207 coaxial with the moving ring 201.

[0030] The outer wall of the inner shell 101 can form a sealed chamber with the annular groove 207. The other end of the air passage 206 extends to the annular groove 207. When the external vacuum device generates negative pressure in the air passage 206 and the annular groove 207, the corresponding position of the outer wall of the inner shell 101 can be sucked into the annular groove 207.

[0031] Further, see also Figure 5 The inner wall of the inner shell 101 is provided with a support ring 208 coaxial with it, and the support ring 208 is used to press the inner shell 101 into the annular groove 207.

[0032] The support ring 208 is closed in its circumferential direction, which can apply an outward radial force to the support ring 208, causing the corresponding position of the inner shell 101 to deform and be squeezed into the annular groove 207, thereby further ensuring the sealing of the side cavity 209.

[0033] Further, see Figures 5 to 10A side cavity 209 is formed between the inner protrusion 202 and the moving ring 201. The side cavity 209 is equipped with a first pump body 210, which is used to pump a heat-conducting medium into the side cavity 209. The side cavity 209 has a first through hole 211 that communicates with the jacket cavity 103. The heat-conducting medium in the side cavity 209 can be discharged to the jacket cavity 103 through the first through hole 211.

[0034] The heat transfer medium can be a molten salt mixture capable of storing and transferring heat, such as a binary molten salt of sodium nitrate and potassium nitrate, which possesses high-temperature stability, good thermal conductivity, and fluidity. However, when the above-mentioned molten salt mixture is used as the heat transfer medium, the heat transfer medium is introduced from bottom to top and flows within the jacket cavity 103. As the heat transfer medium flows upward, its flow velocity gradually decreases, and a boundary layer or flow dead zone is generated in the upper part of the jacket cavity 103, further generating a crystalline scale layer, reducing the heat transfer coefficient of the heat transfer medium, narrowing the flow channel of the jacket cavity 103, and even causing blockage. The present invention pumps a heat-conducting medium into the side cavity 209 through the first pump body 210. The heat-conducting medium in the side cavity 209 is discharged to the jacket cavity 103 through the first through hole 211, so as to force circulation and disturb the heat-conducting medium in the jacket cavity 103, so as to maintain a certain high flow rate of the heat-conducting medium, thereby avoiding the generation of boundary layer or flow dead zone in the upper part of the jacket cavity 103 to a certain extent, avoiding the generation of crystalline scale layer, maintaining the heat transfer coefficient of the heat-conducting medium, and preventing the flow channel of the jacket cavity 103 from shrinking or even becoming blocked.

[0035] Furthermore, when the first pump body 210 pumps the heat-conducting medium into the side cavity 209, it has an inflow rate. When the heat-conducting medium in the side cavity 209 is discharged from the first through hole 211 to the jacket cavity 103, it has an outflow rate. When the inner protrusion 202 moves from top to bottom, the inflow rate is greater than the outflow rate, causing the inner protrusion 202 to gradually increase in size.

[0036] The bottom layer of mixed material is more likely to adhere to the inner wall of the inner shell 101 due to its greater pressure. When the inner protrusion 202 moves from top to bottom, the pumped flow rate is greater than the discharged flow rate, causing the inner protrusion 202 to gradually increase in size. This adapts to the different pressures exerted by the mixed material at different heights. Specifically, when cleaning the mixed material adhering to the top of the inner wall of the inner shell 101, the inner protrusion 202 is smaller, which can reduce the damage to the inner shell 101 to a certain extent. When cleaning the mixed material adhering to the bottom of the inner wall of the inner shell 101, the inner protrusion 202 is larger to ensure the cleaning effect.

[0037] Furthermore, as the inner protrusion 202 moves from top to bottom, the pump flow rate alternately increases and decreases, causing the inner protrusion 202 to gradually increase intermittently. The inner protrusion 202 gradually increases in a fluctuating manner, thereby improving cleaning efficiency.

[0038] Further, see Figure 6The moving ring 201 is provided with a conduit 213, and the first through hole 211 is connected to the jacket cavity 103 through the conduit 213. The end of the conduit 213 is set upward.

[0039] The heat-conducting medium in the side cavity 209 is discharged upward to the jacket cavity 103 through the first through hole 211 and the conduit 213, so as to specifically force circulation and disturb the heat-conducting medium in the upper part of the jacket cavity 103, so that the heat-conducting medium in the upper part of the jacket cavity 103 also maintains a certain high-speed flow, further avoiding the generation of boundary layer or flow dead zone in the upper part of the jacket cavity 103, avoiding the generation of crystalline scale layer, maintaining the heat transfer coefficient of the heat-conducting medium, and avoiding the narrowing or even blockage of the flow channel in the jacket cavity 103.

[0040] The movable ring 201 has a second through hole 212, one end of which is connected to the side cavity 209.

[0041] The first pump body 210 is located outside the moving ring 201. The suction end of the first pump body 210 is located inside the heat-conducting medium of the jacket cavity 103, and the discharge end of the first pump body 210 is connected to the other end of the second through hole 212. Therefore, the first pump body 210 draws in the heat-conducting medium in the jacket cavity 103 and pumps it into the side cavity 209 through the discharge end of the first pump body 210 and the second through hole 212, which can force circulation and agitation of the heat-conducting medium in the lower part of the jacket cavity 103. A second pump body 214 is also provided outside the moving ring 201. The suction end of the second pump body 214 is connected to the first through hole 211, and the conduit 213 is located at the discharge end of the second pump body 214 and is located inside the heat-conducting medium of the jacket cavity 103. Therefore, the second pump body 214 draws in the heat-conducting medium in the side cavity 209 through the first through hole 211 and pumps it into the jacket cavity 103 through the discharge end of the second pump body 214. This enables forced circulation of the heat-conducting medium in the jacket cavity 103 and the heat-conducting medium in the side cavity 209, while also heating the inner protrusion 202.

[0042] As the inner convex portion 202 moves from top to bottom, the pumping flow rate of the first pump body 210 is controlled to be larger while the discharge flow rate of the second pump body 214 is smaller, causing the inner convex portion 202 to gradually increase. Furthermore, the pumping flow rate of the first pump body 210 is controlled to alternately increase and decrease, causing the inner convex portion 202 to intermittently increase gradually. Even further, the suction end of the first pump body 210 is positioned downwards to draw in the heat-conducting medium located below the first pump body 210 within the jacket cavity 103, while the conduit 213 at the discharge end of the second pump body 214 is positioned upwards to discharge the heat-conducting medium in the side cavity 209 upwards into the jacket cavity 103 located above the first pump body 210. This forces circulation and agitation of the heat-conducting medium in both the upper and lower parts of the jacket cavity 103, maintaining a certain high-speed flow of the heat-conducting medium in both parts of the jacket cavity 103. Furthermore, multiple equal numbers of the first pump body 210 and the second pump body 214 can be provided, for example, three of each. The first pump body 210 and the second pump body 214 are staggered in the circumferential direction of the moving ring 201 to more evenly circulate the heat-conducting medium in the jacket cavity 103 and the heat-conducting medium in the side cavity 209. Correspondingly, the first through hole 211 and the second through hole 212 are staggered in the circumferential direction of the moving ring 201. The first pump body 210 and the second pump body 214 are each equipped with a corresponding power source and control module to control start-up, shutdown, and operating conditions. Since the first pump body 210 and the second pump body 214 are both located within the heat-conducting medium of the jacket cavity 103, they need to be cooled. Multiple second protective covers 215 can be provided on the moving ring 201. The first pump body 210 and the second pump body 214 are respectively located in the corresponding second protective covers 215. The second protective covers 215 are filled with cooling medium to cool the first pump body 210 and the second pump body 214.

[0043] Optionally, the first through hole 211 and the second through hole 212 are both set at an angle to the radial line of the moving ring 201, so as to force the heat-conducting medium in the side cavity 209 to circulate and disturb it.

[0044] Furthermore, the end of catheter 213 is positioned obliquely upward.

[0045] The heat-conducting medium in the side cavity 209 is discharged obliquely upward to the jacket cavity 103 through the first through hole 211 and the conduit 213, which increases the degree of forced circulation and disturbance of the heat-conducting medium in the upper part of the jacket cavity 103, further avoids the generation of boundary layer or flow dead zone in the upper part of the jacket cavity 103, avoids the generation of crystalline scale layer, maintains the heat transfer coefficient of the heat-conducting medium, and avoids the shrinkage or even blockage of the flow channel in the jacket cavity 103.

[0046] The suction end of the first pump body 210 is also inclined downward, with the inclination direction being the same as or opposite to that of the conduit 213, so as to enhance the degree of forced circulation and disturbance of the heat-conducting medium in the lower part of the jacket cavity 103.

[0047] This invention also provides a granulation process for battery negative electrode materials, including the following steps: S01, graphite powder and carbon-based binder simultaneously enter the inner shell 101 from the top in the form of atomization. The stirring component 104 is started to stir the graphite powder and carbon-based binder and form a mixture. The highest position of the mixture in the inner shell 101 gradually rises, and the moving ring 201 and the inner protrusion 202 move synchronously from bottom to top. S02, the highest position of the mixture inside the inner shell 101 stops rising, and the moving ring 201 and the inner protrusion 202 remain stationary, while the stirring component 104 continues to start for the first time; S03, when the agitator 104 stops, the moving ring 201 and the inner protrusion 202 move synchronously from top to bottom, and then synchronously from bottom to top; S04. Repeat S02 and S03 a preset number of times; S05. Inert gas is introduced into the inner shell 101, and the temperature is raised to the pre-curing temperature using a heat-conducting medium and kept at that temperature to allow the carbon-based adhesive to undergo initial cross-linking. S06. Continue heating to the carbonization temperature and hold the temperature to allow the carbon-based binder to pyrolyze and transform into a binding carbon phase, thus completing the coating and granulation of graphite particles. S07. Cool to discharge temperature to obtain artificial graphite secondary granulation precursor.

[0048] In S05, the pre-curing temperature is 80 to 150°C, and the holding time is 0.5 to 2 hours. In S06, the carbonization temperature is 400 to 700°C, and the holding time is 1 to 4 hours. In S07, natural cooling or forced cooling with inert gas is used, and the material is discharged after cooling to below 100°C. Furthermore, in S05 to S07, the agitator 104 can continue to operate, with the agitation speed decreasing sequentially.

[0049] The working principle of Embodiment 1 of the present invention is as follows: An external vacuum device creates negative pressure within the air passage 206 and the annular groove 207, drawing the corresponding position of the outer wall of the inner shell 101 into the annular groove 207. Simultaneously, the support ring 208 presses the inner shell 101 into the annular groove 207, temporarily fixing the corresponding position of the outer wall of the inner shell 101. This forms an inner protrusion 202 between the two contact parts of the inner shell 101, ensuring a seal against the side cavity 209. A heat-conducting medium is circulated into the jacket cavity 103 through the first inlet 109 and the first outlet 111, and an insulation medium is circulated into the insulation pipe 113 to insulate the heat-conducting medium within the jacket cavity 103. Graphite powder is introduced through the feed port 105, and compressed gas is introduced through the first air inlet 106, causing the graphite powder to enter the inner shell 101 from the top in an atomized form. Simultaneously, carbon-based binder is introduced through liquid inlet 107 and compressed gas is introduced through second air inlet 108, causing the carbon-based binder to enter the inner shell 101 in atomized form from the top. Inside the inner shell 101, the binder undergoes gas-phase collision and mixing with the atomized graphite powder. Simultaneously, motor 114 drives agitator 104 to rotate, stirring the graphite powder and carbon-based binder to form a mixture. The highest point of the mixture inside the inner shell 101 gradually rises, and telescopic cylinder 204 drives moving ring 201 to move synchronously from bottom to top, causing inner protrusion 202 to move from bottom to top. The position of inner protrusion 202 matches the highest point of the mixture inside the inner shell 101, guiding the mixture towards the center of the inner shell 101, preventing it from adhering to the inner wall of the inner shell 101 and further accumulating to form scale and a stagnant zone.

[0050] Feeding stops when the highest point of the mixture inside the inner shell 101 reaches a certain height, and the moving ring 201 and the inner protrusion 202 remain stationary. The motor 114 drives the stirring component 104 to continue rotating for a short time to continue stirring the graphite powder and carbon-based binder to form a mixture. The inner protrusion 202 continues to guide the mixture towards the center of the inner shell 101, preventing it from adhering to the inner wall of the inner shell 101 and further accumulating to form scale and evolve into a stagnant zone. Afterward, the stirring component 104 stops, and the telescopic cylinder 204 drives the moving ring 201 to move rapidly from top to bottom, causing the inner protrusion 202 to move from top to bottom, causing the mixture still adhering to the inner wall of the inner shell 101 to peel off and be cleaned, reducing cleaning difficulty and downtime, and ensuring the continuity and stability of production. The mixture in the stagnant zone and the peeled-off mixture can continue to participate in the system's circulating mixing and coating, ensuring mixing uniformity and coating consistency to a certain extent, avoiding affecting the battery's rate performance, cycle stability, and material yield. Repeat the above steps a preset number of times to ensure the mixing effect of the mixture.

[0051] The first pump body 210 draws in the heat-conducting medium located below the jacket cavity 103 and pumps it into the side cavity 209 through the discharge end of the first pump body 210 and the second through hole 212, which can force circulation and agitation of the heat-conducting medium in the lower part of the jacket cavity 103. The second pump body 214 draws in the heat-conducting medium in the side cavity 209 through the first through hole 211 and discharges it obliquely upward through the discharge end of the second pump body 214 and the conduit 213 into the jacket cavity 103 located above the first pump body 210, so as to force circulation and agitation of the heat-conducting medium in the upper part of the jacket cavity 103, maintain a certain high flow velocity of the heat-conducting medium, and to a certain extent avoid the generation of boundary layer or flow dead zone in the upper part of the jacket cavity 103, avoid the generation of crystalline scale layer, maintain the heat transfer coefficient of the heat-conducting medium, and avoid the narrowing or even blockage of the flow channel of the jacket cavity 103. Furthermore, as the inner protrusion 202 moves from top to bottom, the pumping flow rate of the first pump body 210 through the second through hole 212 is greater than the discharge flow rate of the second pump body 214 through the first through hole 211, causing the inner protrusion 202 to gradually increase in size. This adapts to the different pressures exerted on the mixed materials at different heights, ensuring effective cleaning of the mixed materials adhering to the inner wall of the inner shell 101. Simultaneously, the pumping flow rate alternately increases and decreases, causing the inner protrusion 202 to gradually increase in a fluctuating manner, thereby improving cleaning efficiency.

[0052] Then, inert gas is introduced into the inner shell 101 through the second inlet 110, and the temperature is raised to the pre-curing temperature using a heat-conducting medium and kept at that temperature to allow the carbon-based binder to undergo initial cross-linking. The temperature is then raised to the carbonization temperature and kept at that temperature to allow the carbon-based binder to undergo pyrolysis and transform into a bonding carbon phase, thus completing the coating and bonding granulation of graphite particles. The material is then cooled to the discharge temperature to obtain the precursor for secondary granulation of artificial graphite.

[0053] Example 2 like Figures 11 to 16 As shown, Embodiment 2 of the present invention provides a granulation device for battery negative electrode material. The difference between it and Embodiment 1 is that the contact part includes at least two annular grooves 207 coaxial with the moving ring 201. In this embodiment, the support ring 208 may not be provided. The sealing of the side cavity 209 is ensured by the multi-layer sealing structure formed by multiple annular grooves 207.

[0054] Example 3 like Figure 17 and Figure 18As shown, Embodiment 3 of the present invention provides a granulation device for battery negative electrode material, which differs from Embodiment 1 in that: multiple first pump bodies 210 are provided only on the outer shell 102, and no additional heat dissipation is required for the first pump bodies 210. The suction end of the first pump body 210 is connected to the external tank storing the heat transfer medium, and the discharge end of the first pump body 210 is connected to the second through hole 212. No conduit 213 is provided; the first through hole 211 is directly connected to the jacket cavity 103. The first pump body 210 pumps the external heat transfer medium into the side cavity 209 through the second through hole 212. The heat transfer medium in the side cavity 209 is directly discharged to the jacket cavity 103 through the first through hole 211. This also achieves the above-mentioned functions: forced circulation and disturbance of the heat transfer medium in the jacket cavity 103, maintaining a certain high flow rate, and to a certain extent avoiding the formation of a boundary layer or flow dead zone in the upper part of the jacket cavity 103, avoiding the formation of a scale layer, maintaining the heat transfer coefficient of the heat transfer medium, and preventing the flow channel of the jacket cavity 103 from narrowing or even becoming blocked. It also allows the inner convex portion 202 to gradually increase intermittently.

[0055] The working principle of Embodiment 3 of the present invention differs from that of Embodiment 1 as follows: The first pump body 210 pumps the external heat-conducting medium into the side cavity 209 through the second through hole 212. The heat-conducting medium in the side cavity 209 is directly discharged into the jacket cavity 103 through the first through hole 211. This forces circulation and agitation of the heat-conducting medium in the jacket cavity 103, maintaining a certain high flow rate. This helps to prevent the formation of a boundary layer or flow dead zone in the upper part of the jacket cavity 103, avoids the formation of scale, maintains the heat transfer coefficient of the heat-conducting medium, and prevents the flow channels of the jacket cavity 103 from narrowing or even becoming blocked. Furthermore, when the inner protrusion 202 moves from top to bottom, the pumping flow rate of the first pump body 210 through the second through hole 212 is greater than the discharge flow rate through the first through hole 211, causing the inner protrusion 202 to gradually increase in size. This adapts to the different pressures exerted on the mixture at different heights, ensuring effective cleaning of the mixture adhering to the inner wall of the inner shell 101.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A granulation device for battery negative electrode material, characterized in that, The system comprises an inner shell and an outer shell, both vertically arranged and nested within each other, with a jacketed cavity formed between them. The jacketed cavity is filled with a heat-conducting medium. Graphite powder and a carbon-based binder simultaneously enter the inner shell from the top in an atomized form. A stirring element is located at the bottom of the inner shell to stir the graphite powder and carbon-based binder and form a mixture. The inner shell is made of an elastic material, and a moving ring is fitted around it. The moving ring causes the inner shell to deform and form an inwardly protruding part. The moving ring has a first state and a second state. In the first state, the stirring element is activated, and the moving ring moves from bottom to top, causing the inwardly protruding part to move from bottom to top, with the position of the inwardly protruding part matching the highest position of the mixture inside the inner shell. In the second state, the stirring element is stopped, and the moving ring moves from top to bottom, causing the inwardly protruding part to move from top to bottom.

2. The granulation equipment for battery negative electrode material according to claim 1, characterized in that, The inner wall of the moving ring has two contact portions spaced vertically. These contact portions contact the outer wall of the inner shell and generate suction on it, so that the inner shell forms an inner convex portion between the two contact portions.

3. The granulation equipment for battery negative electrode material according to claim 2, characterized in that, A side cavity is formed between the inner protrusion and the moving ring. A first pump body is disposed in the side cavity. The first pump body is used to pump the heat-conducting medium into the side cavity. The side cavity has a first through hole that communicates with the jacket cavity. The heat-conducting medium in the side cavity can be discharged to the jacket cavity through the first through hole.

4. The granulation equipment for battery negative electrode material according to claim 3, characterized in that, When the first pump body pumps the heat-conducting medium into the side cavity, it has an inflow rate. When the heat-conducting medium in the side cavity is discharged to the jacket cavity through the first through hole, it has an outflow rate. When the inner convex part moves from top to bottom, the inflow rate is greater than the outflow rate, causing the inner convex part to gradually increase in size.

5. The granulation equipment for battery negative electrode material according to claim 4, characterized in that, As the inner convex part moves from top to bottom, the pump flow rate alternately increases and decreases, causing the inner convex part to gradually increase intermittently.

6. The granulation equipment for battery negative electrode material according to claim 3, characterized in that, The movable ring is equipped with a conduit, and the first through hole is connected to the jacket cavity through the conduit. The end of the conduit is set upward.

7. The granulation equipment for battery negative electrode material according to claim 6, characterized in that, The end of the catheter is positioned at an angle upwards.

8. The granulation equipment for battery negative electrode material according to claim 2, characterized in that, The contact part is an annular groove coaxial with the moving ring.

9. The granulation equipment for battery negative electrode material according to claim 3, characterized in that, The inner wall of the inner shell is provided with a support ring coaxial with it, which is used to press the inner shell into the annular groove.

10. A granulation process for a battery negative electrode material, applied to the granulation equipment for the battery negative electrode material according to any one of claims 1 to 9, characterized in that, Includes the following steps: S01. Graphite powder and carbon-based binder enter the inner shell from the top in the form of atomization. The agitator is started to stir the graphite powder and carbon-based binder and form a mixture. The highest position of the mixture in the inner shell gradually rises, and the moving ring and the inner protrusion move synchronously from bottom to top. S02, the highest position of the mixture inside the inner shell stops rising, and the moving ring and inner protrusion remain stationary, while the agitator continues to start immediately; S03. When the agitator stops, the moving ring and the inner protrusion move synchronously from top to bottom, and then synchronously from bottom to top. S04. Repeat S02 and S03 a preset number of times; S05. Inert gas is introduced into the inner shell, and the temperature is raised to the pre-curing temperature using a heat-conducting medium and kept at that temperature to allow the carbon-based binder to undergo initial cross-linking. S06. Continue heating to the carbonization temperature and hold the temperature to allow the carbon-based binder to pyrolyze and transform into a binding carbon phase, thus completing the coating and granulation of graphite particles. S07. Cool to discharge temperature to obtain artificial graphite secondary granulation precursor.

Images