Silicon-carbon negative electrode material preparation method and application

Abstract

The application belongs to the technical field of battery materials, and particularly relates to a preparation method and application of a silicon-carbon negative electrode material, which comprises the following steps: adding silicon powder and carbon raw materials into a mixing machine and mixing and stirring; conveying the mixed materials into a screening machine to screen out unqualified components; coating the mixed materials with liquid carbon; conveying the coated materials into a sintering furnace for secondary sintering; cleaning the sintered materials with a cleaning agent, and drying to obtain the silicon-carbon negative electrode material. The screening assembly is arranged, the fixed rod is driven to rotate by the first motor, and then the screening cylinder is driven to rotate, so that the too small particles in the silicon powder are thrown out of the through hole into the collecting cylinder under the action of centrifugal force, and the mixing of the silicon powder and the carbon raw materials is more uniform. The impact assembly is arranged, the impact ball reciprocally impacts the through hole under the elastic force of the spring while the fixed rod rotates, and the through hole is prevented from being blocked.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, and in particular relates to the preparation method and application of silicon-carbon anode materials. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles and aerospace due to their high energy density, good cycle performance, and light weight. In the production process of lithium batteries, the preparation of negative electrode materials is one of the important factors affecting the quality of lithium battery products.

[0003] A search revealed a patent document with publication number CN111106333B that discloses a silicon-carbon anode material, its preparation method, and its application. The method includes: mixing silicon powder and a solid carbon source in a V-type mixer; adding a liquid carbon source to the V-type mixer in a spray form, and further mixing to obtain a mixture; sending the mixture to a high-speed crusher, whereby the liquid carbon source is drawn into a film and coated onto the surface of the silicon powder and solid carbon source mixture to obtain a mixture with a coating layer; and calcining the mixture with the coating layer under an inert atmosphere to obtain the silicon-carbon anode material.

[0004] Although the above preparation method can produce silicon-carbon anode materials with uniform dispersion and stable composite structure of silicon and carbon, the following problems still exist in the preparation process:

[0005] Before mixing silicon powder, it needs to be ground. However, the above preparation method cannot screen the ground silicon powder, resulting in uneven particle size. This makes it impossible to mix silicon powder and carbon raw materials more evenly, thus reducing the mixing effect of silicon powder and carbon raw materials. Summary of the Invention

[0006] The purpose of this invention is to address the problem mentioned in the background art, which is that the inability to screen silicon powder leads to uneven particle size and reduced mixing effect. The invention provides a method for preparing silicon-carbon anode materials that can screen out excessively small particles in silicon powder, resulting in more uniform particle size.

[0007] To achieve the above objectives, the present invention adopts the following technical solutions:

[0008] Methods for preparing silicon-carbon anode materials include:

[0009] S1: Add silicon powder and carbon raw materials into the mixer and mix them.

[0010] S2: The mixed material is conveyed to a screening machine to remove unqualified components;

[0011] S3: Coating the mixture with liquid carbon;

[0012] S4: The coated material is transported to the sintering furnace for secondary sintering;

[0013] S5: The sintered material is cleaned with a cleaning agent, and then dried to obtain silicon-carbon anode material.

[0014] Preferably, in step S2, the screening machine includes:

[0015] The base has two side plates fixedly connected to its upper part, a screening cylinder is rotatably connected between the two side plates on the upper part of the base, and a feeding cylinder is fixedly connected to the base. One side of the feeding cylinder extends into the screening cylinder, and the other side extends to the bottom of the base.

[0016] A screening assembly includes a fixed plate, a first motor, a fixed rod, several through holes, and a collection cylinder. One of the two side plates is fixedly connected to the fixed plate above the screening cylinder. The fixed plate is equipped with the first motor, and the output shaft of the first motor is fixedly connected to the fixed rod. The fixed rod extends into the interior of the screening cylinder and is fixedly connected to the screening cylinder. Several through holes are provided on the side wall of the screening cylinder. A collection cylinder is fixedly connected between the two side plates, and the screening cylinder communicates with the interior of the collection cylinder through the several through holes.

[0017] The impact assembly includes an incomplete gear, a support plate, two guide rails, two racks, two springs, and two impact balls. The portion of the fixed rod extending into the screening cylinder is interference-fitted with the incomplete gear. The top of the conveying cylinder is fixedly connected to the support plate, and two guide rails are fixedly connected to the support plate. Racks are slidably connected to both guide rails, and the two racks are elastically connected to the inner walls of the two guide rails through two springs. Both racks can mesh with the incomplete gear, and impact balls are fixedly connected to the side of each rack near the inner wall of the screening cylinder.

[0018] Preferably, it further includes:

[0019] The stirring assembly includes a limiting plate, a slot, a first gear, several stirring rods, and several second gears. The limiting plate is fixedly connected to the top of the base. The limiting plate has a slot. The axis of the screening cylinder is rotatably connected to the center of the slot. The first gear is interference-fitted at the axis of the screening cylinder. Several stirring rods are rotatably connected in the slot. Each stirring rod is interference-fitted with a second gear, and each second gear meshes with the first gear.

[0020] Preferably, the conveying cylinder has a conveying chamber, the top of the conveying chamber is fixedly connected to a second motor, the output shaft of the second motor is fixedly connected to an auger, and the conveying chamber is connected to the inside of the screening cylinder through a conveying port.

[0021] Preferably, a feed hopper is provided above the screening cylinder.

[0022] Preferably, when the incomplete gear rotates to mesh with the rack, it drives the rack away from the inner wall of the screening cylinder.

[0023] Preferably, each of the stirring rods extends into the screening cylinder and is fixedly connected with several stirring blades.

[0024] Preferably, a valve is provided inside the feed inlet.

[0025] The application of silicon-carbon anode materials prepared by any of the preparation methods described herein to prepare lithium-ion batteries.

[0026] Compared with existing technologies, the advantages of the template of this invention are:

[0027] 1. By setting up a screening component, the present invention can drive the fixed rod to rotate through the first motor, thereby driving the screening cylinder to rotate. This causes the mixture inside the screening cylinder to rotate with the screening cylinder. Under the action of centrifugal force, the excessively small particles in the silicon powder are thrown out through the through holes into the collection cylinder, making the particle size of the silicon powder more uniform and the mixing of silicon powder and carbon raw materials more uniform.

[0028] 2. By setting up an impact component, the present invention can drive the rack to reciprocate away from the inner wall of the screening cylinder through the incomplete gear while the fixed rod rotates, so that the impact ball reciprocates to impact the through hole under the elastic force of the spring, thus preventing the through hole from becoming blocked.

[0029] 3. By setting up a stirring assembly, the present invention drives several stirring rods to rotate through the first and second gears while the screening cylinder rotates, and further stirs and mixes the mixture through the stirring blades, so as to achieve a better mixing effect of silicon powder and carbon raw materials.

[0030] 4. By setting up a feeding cylinder, after the screening and mixing are completed, the second motor can drive the auger to rotate and transport the mixture in the screening cylinder to the outside of the screening cylinder, which facilitates the rapid progress of the next preparation operation. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the process of preparing silicon-carbon anode materials provided by the present invention.

[0032] Figure 2 This is a schematic diagram of the screening machine in this invention;

[0033] Figure 3 yes Figure 2 Enlarged view of point A in the middle;

[0034] Figure 4This is a top view of the impact component in this invention.

[0035] Figure 5 This is a top view of the screening machine in this invention;

[0036] Figure 6 This is a top view of the stirring assembly in this invention.

[0037] Figure 7 This is a schematic diagram of the internal structure of the feed cylinder in this invention.

[0038] In the diagram, 1. Screening machine; 2. Base; 21. Side plate; 22. Screening cylinder; 23. Feeding cylinder; 231. Feeding chamber; 232. Second motor; 233. Screwdriver; 234. Feeding port; 3. Screening assembly; 31. Fixing plate; 32. First motor; 33. Fixing rod; 34. Through hole; 35. Collection cylinder; 4. Impact assembly; 41. Incomplete gear; 42. Support plate; 43. Guide rail; 44. Rack; 45. Spring; 46. Impact ball; 5. Stirring assembly; 51. Limiting plate; 52. Empty trough; 53. First gear; 54. Stirring rod; 541. Stirring blade; 55. Second gear. Detailed Implementation

[0039] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0040] Reference Figure 1 Methods for preparing silicon-carbon anode materials include:

[0041] S1: Add silicon powder and carbon raw materials into the mixer and mix them.

[0042] S2: The mixed material is conveyed to screening machine 1 to remove unqualified components;

[0043] S3: Coating the mixture with liquid carbon;

[0044] S4: The coated material is transported to the sintering furnace for secondary sintering;

[0045] S5: The sintered material is cleaned with a cleaning agent, and then dried to obtain silicon-carbon anode material.

[0046] Reference Figure 2-5 In the method for preparing silicon-carbon anode materials, in step S2, the screening machine 1 includes:

[0047] The base 2 has two side plates 21 fixedly connected to its top. A screening cylinder 22 is rotatably connected between the two side plates 21 on the top of the base 2. A conveying cylinder 23 is fixedly connected to the base 2. One side of the conveying cylinder 23 extends into the screening cylinder 22, and the other side extends to the bottom of the base 2.

[0048] The screening component 3 includes a fixed plate 31, a first motor 32, a fixed rod 33, several through holes 34, and a collection cylinder 35. One of the two side plates 21 is fixedly connected to the fixed plate 31 at a position above the screening cylinder 22. The first motor 32 is mounted on the fixed plate 31, and the fixed rod 33 is fixedly connected to the output shaft of the first motor 32. The fixed rod 33 extends into the interior of the screening cylinder 22 and is fixedly connected to the screening cylinder 22. Several through holes 34 are opened on the side wall of the screening cylinder 22. The collection cylinder 35 is fixedly connected between the two side plates 21, and the screening cylinder 22 communicates with the interior of the collection cylinder 35 through the several through holes 34.

[0049] A feeding hopper is provided above the screening cylinder 22, through which the mixture can be transported into the screening cylinder 22. After the mixture is transported into the screening cylinder 22, the first motor 32 drives the fixed rod 33 to rotate, which in turn drives the screening cylinder 22 to rotate. This causes the mixture in the screening cylinder 22 to rotate with the screening cylinder 22. Under the action of centrifugal force, the excessively small particles in the silicon powder are thrown out into the collection cylinder through several through holes 34, making the particle size of the silicon powder more uniform and the mixing of silicon powder and carbon raw materials more uniform, thereby improving the quality of the manufactured lithium battery products.

[0050] Impact assembly 4 includes an incomplete gear 41, a support plate 42, two guide rails 43, two racks 44, two springs 45, and two impact balls 46. The part of the fixed rod 33 extending into the screening cylinder 22 is interference-fitted with the incomplete gear 41. The top of the feed cylinder 23 is fixedly connected to the support plate 42. Two guide rails 43 are fixedly connected to the support plate 42. Racks 44 are slidably connected to both guide rails 43. The two racks 44 are elastically connected to the inner walls of the two guide rails 43 through two springs 45. Both racks 44 can mesh with the incomplete gear 41. Impact balls 46 are fixedly connected to the side of the two racks 44 near the inner wall of the screening cylinder 22.

[0051] It is worth mentioning that when the incomplete gear 41 rotates to mesh with the rack 44, it drives the rack 44 away from the inner wall of the screening cylinder 22. When the incomplete gear 41 is no longer meshing with the rack 44, the rack 44 approaches and impacts the inner wall of the screening cylinder 22 under the elastic force of the spring 45. While the fixed rod 33 rotates, it drives the incomplete gear 41 to rotate, which causes the two impact balls 46 to intermittently impact the inner wall of the screening cylinder 22 and impact its through hole 34 to prevent the through hole 34 from becoming blocked.

[0052] Reference Figure 2 and Figure 6 The method for preparing silicon-carbon anode materials, the screening machine 1 further includes:

[0053] The stirring assembly 5 includes a limiting plate 51, a slot 52, a first gear 53, several stirring rods 54, and several second gears 55. The limiting plate 51 is fixedly connected to the top of the base 2. The slot 52 is opened on the limiting plate 51. The axis of the screening cylinder 22 is rotatably connected to the center of the slot 52. The first gear 53 is interference-fitted at the axis of the screening cylinder 22. Several stirring rods 54 are rotatably connected in the slot 52. Each stirring rod 54 is interference-fitted with a second gear 55. Each second gear 55 meshes with the first gear 53.

[0054] Each stirring rod 54 extends into the screening cylinder 22 and is fixedly connected to several stirring blades 541. When the screening cylinder 22 rotates, the first gear 53 drives several second gears 55 to rotate, thereby causing several stirring rods 54 to rotate synchronously. This not only limits the screening cylinder 22 to prevent it from rotating too fast and deviating from its position, but also drives the stirring blades 541 on the stirring rods 54 to rotate rapidly, further stirring and mixing the mixture, resulting in a better mixing effect between silicon powder and carbon raw materials.

[0055] Reference Figure 2 and Figure 7 The conveying cylinder 23 has a conveying chamber 231 inside. A second motor 232 is fixedly connected to the top of the conveying chamber 231. An auger 233 is fixedly connected to the output shaft of the second motor 232. The conveying chamber 231 is connected to the inside of the screening cylinder 22 through the conveying port 234.

[0056] A valve is installed inside the feeding port 234. After screening is completed, the feeding port 234 is opened by the valve, and then the second motor 232 drives the auger 233 to rotate, so as to quickly feed the mixture in the screening cylinder 22, which facilitates the next preparation operation.

[0057] The functional principle of this invention can be explained through the following operational methods:

[0058] After the mixture is stirred, it is conveyed into the screening cylinder 22. Then the first motor 32 is turned on, which drives the fixed rod 33 to rotate, so that the screening cylinder 22, the incomplete gear 41 and the first gear 53 rotate synchronously.

[0059] The rotation of the screening cylinder 22 enables the silicon powder in the mixture to be thrown out under the action of centrifugal force, making the silicon powder particles in the mixture more uniform in size.

[0060] The rotation of the incomplete gear 41 drives the two racks 44 to reciprocate horizontally, which in turn causes the impact ball 46 to reciprocate to impact the inner wall of the screening cylinder 22, preventing silicon powder particles from clogging the through holes.

[0061] The rotation of the first gear 53 can drive several stirring rods 54 to rotate through the second gear 55, causing the stirring blades 541 to rotate rapidly, further stirring and mixing the mixture, and improving the mixing effect of silicon powder and carbon raw materials.

[0062] After screening, the valve is opened and the second motor 232 is activated, and the mixture is quickly fed out through the auger 233.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing silicon-carbon anode materials, characterized in that, include: S1: Add silicon powder and carbon raw materials into the mixer and mix them. S2: The mixed material is conveyed to the screening machine (1) to remove unqualified components; S3: Coating the mixture with liquid carbon; S4: The coated material is transported to the sintering furnace for secondary sintering; S5: The sintered material is cleaned with a cleaning agent and then dried to obtain silicon-carbon anode material; In step S2, the screening machine (1) includes: The base (2) has two side plates (21) fixedly connected above it. A screening cylinder (22) is rotatably connected between the two side plates (21) above the base (2). A conveying cylinder (23) is fixedly connected on the base (2). One side of the conveying cylinder (23) extends into the screening cylinder (22), and the other side extends to the bottom of the base (2). The screening component (3) includes a fixed plate (31), a first motor (32), a fixed rod (33), several through holes (34), and a collection cylinder (35). One of the two side plates (21) is fixedly connected to the fixed plate (31) above the screening cylinder (22). The fixed plate (31) is provided with the first motor (32). The output shaft of the first motor (32) is fixedly connected to the fixed rod (33). The fixed rod (33) extends into the interior of the screening cylinder (22) and is fixedly connected to the screening cylinder (22). Several through holes (34) are provided on the side wall of the screening cylinder (22). The collection cylinder (35) is fixedly connected between the two side plates (21). The screening cylinder (22) communicates with the interior of the collection cylinder (35) through several through holes (34). Impact assembly (4), the impact assembly (4) includes an incomplete gear (41), a support plate (42), two guide rails (43), two racks (44), two springs (45) and two impact balls (46). The part of the fixed rod (33) extending into the screening cylinder (22) is interference-fitted with the incomplete gear (41). The top of the feed cylinder (23) is fixedly connected to the support plate (42). Two guide rails (43) are fixedly connected to the support plate (42). Racks (44) are slidably connected to both guide rails (43). The two racks (44) are elastically connected to the inner walls of the two guide rails (43) through two springs (45). Both racks (44) can mesh with the incomplete gear (41). Impact balls (46) are fixedly connected to the side of the two racks (44) near the inner wall of the screening cylinder (22).

2. The method for preparing silicon-carbon anode material according to claim 1, characterized in that, Also includes: The stirring assembly (5) includes a limiting plate (51), a slot (52), a first gear (53), several stirring rods (54) and several second gears (55). The limiting plate (51) is fixedly connected above the base (2). The slot (52) is provided on the limiting plate (51). The axis of the screening cylinder (22) is rotatably connected to the center of the slot (52). The first gear (53) is interference-fitted at the axis of the screening cylinder (22). Several stirring rods (54) are rotatably connected in the slot (52). Each stirring rod (54) is interference-fitted with a second gear (55). Each second gear (55) meshes with the first gear (53).

3. The method for preparing silicon-carbon anode material according to claim 1, characterized in that, The conveying cylinder (23) has a conveying chamber (231) inside. A second motor (232) is fixedly connected to the top of the conveying chamber (231). An auger (233) is fixedly connected to the output shaft of the second motor (232). The conveying chamber (231) is connected to the inside of the screening cylinder (22) through the conveying port (234).

4. The method for preparing silicon-carbon anode material according to claim 1, characterized in that, A feed hopper is provided above the screening cylinder (22).

5. The method for preparing silicon-carbon anode material according to claim 1, characterized in that, When the incomplete gear (41) rotates to mesh with any rack (44), it drives the rack (44) away from the inner wall of the screening cylinder (22).

6. The method for preparing silicon-carbon anode material according to claim 2, characterized in that, Each of the stirring rods (54) extends into the screening cylinder (22) and is fixedly connected with several stirring blades (541).

7. The method for preparing silicon-carbon anode material according to claim 3, characterized in that, A valve is provided inside the feed inlet (234).

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