Lithium iron phosphate slurry pre-grinding device

Abstract

The utility model discloses a lithium iron phosphate slurry pre-grinding device which comprises a grinding cylinder, and a lithium iron phosphate slurry feeding port and a lithium iron phosphate slurry discharging port are formed in the two opposite sides of the grinding cylinder correspondingly. The grinding discs are located in the grinding cylinder body and are sequentially arranged in the direction from the feeding opening to the discharging opening, meanwhile, the grinding cylinder body is divided into a plurality of grinding spaces and a slurry buffering space, and the grinding spaces are filled with grinding media respectively; wherein a reinforcing rib penetrating through the center of the grinding disc is arranged on the surface of the grinding disc, and protruding parts are arranged at the two ends of the reinforcing rib. The lithium iron phosphate slurry is effectively pre-ground and well pre-dispersed through the pre-grinding device, meanwhile, the design strength of the grinding disc in the grinding device is high, and the service life of the pre-grinding device can be prolonged while the grinding effect is guaranteed.

Description

Technical Field

[0001] This application belongs to the field of lithium iron phosphate cathode material preparation technology for lithium-ion batteries, specifically relating to a lithium iron phosphate slurry pre-grinding device. Background Technology

[0002] In the preparation process of lithium iron phosphate cathode material, it is usually necessary to first disperse iron phosphate, lithium carbonate and glucose in pure water to form a slurry, then pump the slurry into a sand mill for grinding, and finally spray dry, calcin and pulverize to obtain the final lithium iron phosphate product.

[0003] The sand mill in the sand grinding stage mainly consists of a machine body, a grinding cylinder, a sand grinding disc, grinding media (micron-sized zirconium balls), a motor, and a feed pump. The feed pump pumps the slurry to be ground into the grinding cylinder. In the grinding cylinder, the sand grinding disc drives the mixture of material and grinding media to undergo efficient relative motion.

[0004] However, in actual production, it was found that the solid particles in the slurry introduced into the sand mill were too large, causing blockage of the separation filter. Furthermore, the solids in the slurry could not be stably suspended in pure water, resulting in solid-liquid separation and sedimentation. The solids pumped into the sand mill would form a viscous complex with the grinding media, jamming the grinding disc and causing the sand mill to stop.

[0005] Although some multi-stage grinding devices exist in the existing technology that can improve the grinding effect, these grinding devices mostly use multi-stage screens in conjunction with spiral stirring blades. On the one hand, the structure of the screens is unstable and easily damaged, which may lead to the grinding media passing through the screens or entering the slurry. On the other hand, the spiral stirring blades will constantly collide with the grinding media while stirring, which will cause wear and tear on the stirring blades and grinding media, making them prone to damage and making it difficult to guarantee the service life of the device. Utility Model Content

[0006] In view of this, the primary objective of this application is to provide a pre-grinding device for lithium iron phosphate slurry. This application uses a dynamic grinding disc instead of a traditional screen and stirring paddle, which serves to stir and separate the material balls, while reducing damage to the grinding media (grinding balls). This pre-grinding device can effectively and uniformly grind and disperse lithium iron phosphate slurry, ensuring that there are no large particles in the slurry pumped into the sand mill, and allowing the slurry entering the sand mill to be well and uniformly mixed with the grinding media, greatly avoiding the clogging of the separation filter and the adhesion of the grinding media.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] This application discloses a lithium iron phosphate cathode slurry pre-grinding device, comprising:

[0009] A grinding cylinder, wherein a lithium iron phosphate slurry inlet and an outlet are respectively provided on opposite sides of the grinding cylinder;

[0010] Several grinding discs are located inside the grinding cylinder and are arranged sequentially from the feed inlet to the discharge outlet, dividing the grinding cylinder into several grinding spaces and a slurry buffer space. The grinding spaces are filled with grinding media.

[0011] The grinding disc has a reinforcing rib running through its center on its surface, and the two ends of the reinforcing rib have protrusions.

[0012] This application utilizes multiple grinding discs to create multiple grinding spaces within the grinding cylinder. Reinforcing ribs are provided on the surface of the grinding discs, with protrusions at both ends of the reinforcing ribs. The pre-grinding device in this application not only effectively pre-grinds lithium iron phosphate slurry, achieving good pre-dispersion, ensuring that the slurry pumped into the sand mill is free of large particles, but also ensures excellent pre-dispersion, guaranteeing that the slurry entering the sand mill is well and uniformly mixed with the pre-grinding media, preventing clogging of the separation filter and adhesion of the grinding media.

[0013] In this application, a dynamic grinding disc is used to replace the traditional screen. The structure of the grinding disc is improved to enhance its strength. The reinforcing ribs on the surface of the grinding disc and the protrusions at both ends can rotate the grinding media, thereby reducing the risk of grinding media entering the slurry or passing through the screen due to damage to the traditional screen. It also avoids the wear problems of traditional stirring blades and grinding media. In summary, the pre-grinding device of this application improves the grinding effect of lithium iron phosphate slurry and greatly ensures the life of the grinding device.

[0014] In this application, "several" refers to multiple, usually two or more. For example, two, three or four can be set. The specific number can be selected according to actual needs. In some examples, in order to take into account both cost and experimental effect, there are three grinding discs. With this number, a better slurry pre-grinding effect can be achieved.

[0015] In some examples, the surface of the grinding disc is covered with through holes, the diameter of which is smaller than the diameter of the grinding media. These through holes allow the slurry ground in the previous grinding space to pass through and enter the next grinding space, thus achieving slurry screening and flow, and ultimately storing it in a slurry buffer space for discharge. In this application, the diameter of all through holes is smaller than the diameter of the grinding media. This is to ensure slurry screening and flow while preventing the grinding media in the grinding space from passing through the grinding disc. Furthermore, the gradually decreasing diameter of the through holes also increases the speed at which the slurry enters the next grinding space, preventing machine blockage.

[0016] In some examples, the size of the grinding disc increases progressively from the inlet to the outlet. This progressively increasing size design ensures that large particles in the grinding slurry do not skip the through-holes in the grinding disc and flow to the next grinding space. Furthermore, since the particle size distribution of the slurry differs between adjacent grinding spaces, this application designs the grinding disc size to increase progressively from the inlet to the outlet, ensuring a similar slurry exchange rate between adjacent grinding spaces. This results in more uniform grinding dispersion throughout the grinding cylinder, further improving the grinding effect.

[0017] In some examples, the diameter of the grinding media in the grinding space gradually decreases from the feed inlet to the discharge outlet. By setting grinding media of different sizes, slurries of different particle sizes are pre-ground, coarsely ground, and finely processed in stages to obtain an ideal finished slurry.

[0018] In some examples, the capacity of the grinding space and the slurry buffer space decreases progressively from the feed inlet to the discharge outlet. Since the grinding media in different grinding spaces are of different sizes, the progressively decreasing size of the grinding space is designed to ensure effective grinding of particles of different sizes in different grinding spaces, improve the utilization rate of the grinding space, and enhance the grinding effect.

[0019] Understandably, the number of reinforcing ribs on the grinding disc surface can be set as needed, without any particular limitation or requirement. In some examples, there are three sets of reinforcing ribs. Setting multiple sets of reinforcing ribs improves grinding efficiency and effectiveness.

[0020] It is understood that the lithium iron phosphate slurry pre-grinding device described in this application also includes a drive mechanism, which is located on the side of the grinding cylinder. In some examples, the drive mechanism is a motor commonly used in the art. The slurry is effectively ground by rotating the grinding disc through the drive mechanism.

[0021] Specifically, a rotating shaft is mounted on the drive mechanism. The rotating shaft extends into the interior of the grinding cylinder and passes through the center of the grinding disc, and is fixedly connected to the grinding disc. Because the rotating shaft passes through the center of the grinding disc and is fixedly connected to it, under the drive of the drive mechanism, the rotating shaft drives the grinding disc to rotate, thereby grinding the slurry within the grinding space.

[0022] The beneficial effects of this application are:

[0023] The lithium iron phosphate slurry pre-grinding device disclosed in this application is equipped with multiple grinding spaces, and the grinding precision increases step by step. The grinding disc is equipped with reinforcing ribs and protrusions. The lithium iron phosphate slurry is initially ground and dispersed through the first stage of grinding. Then, it is further ground and refined through subsequent grinding, thereby ensuring that there are no large particles in the slurry pumped into the sand mill and that the slurry is well pre-dispersed and there is no sedimentation. The reinforcing ribs and protrusions of the grinding disc drive the grinding balls to rotate and also play a role in improving the strength of the grinding disc, thereby enhancing the grinding efficiency. This allows the slurry entering the sand mill to be well and uniformly mixed with the grinding media, without clogging the separation filter or sticking the grinding media.

[0024] In addition to achieving good pre-grinding and dispersion, the pre-grinding device in this application also has the advantages of high grinding strength, low damage resistance, and long service life. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the internal structure of a lithium iron phosphate slurry pre-grinding device in a preferred embodiment of this application.

[0026] Figure 2 for Figure 1 A schematic diagram of the structure of the intermediate secondary grinding disc 42.

[0027] Figure 3 for Figure 2 A schematic diagram of the side cross-section structure of the intermediate secondary grinding disc 42.

[0028] In the diagram: 1-Grinding cylinder, 11-Inlet, 12-Outlet; 2-Drive mechanism, 21-Rotating shaft; 31-First-stage grinding space, 32-First-stage grinding disc, 33-First-stage grinding ball; 41-Second-stage grinding space, 42-Second-stage grinding disc, 421-Through hole, 422-Reinforcing rib, 423-Protrusion, 43-Second-stage grinding ball; 51-Third-stage grinding space, 52-Third-stage grinding disc, 53-Third-stage grinding ball; 6-Slurry buffer space. Detailed Implementation

[0029] The embodiments of this application will be clearly and completely described below. The technical solutions in the embodiments described below are exemplary and only possible technical implementations of this application, not all possible implementations. Those skilled in the art can combine the embodiments of this application to obtain other embodiments without creative effort, and these embodiments are also within the protection scope of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0031] This embodiment discloses a lithium iron phosphate slurry pre-grinding device, the structure of which is as follows: Figure 1 As shown, the pre-grinding device includes a grinding cylinder 1, with an inlet 11 and an outlet 12 on opposite sides of the grinding cylinder 1. The specific design can be customized as needed. In this embodiment, the inlet 11 and the outlet 12 are respectively located at the top and bottom of the grinding cylinder 1. The inlet 11 is used to allow the mixed lithium iron phosphate slurry to enter the grinding cylinder 1, while the outlet 12 is used to discharge the ground slurry from the grinding cylinder 1.

[0032] Please continue reading. Figure 1 A drive mechanism 2 is installed on the other side of the grinding cylinder 1. In this embodiment, the drive mechanism 2 is a motor. A rotating shaft 21 is installed on the drive mechanism 2, and the rotating shaft 21 can rotate under the drive of the drive mechanism 2. The rotating shaft 21 extends into the interior of the grinding cylinder 1.

[0033] Furthermore, inside the grinding cylinder 1, from the feed inlet 11 to the discharge outlet 12, a primary grinding disc 32, a secondary grinding disc 42, and a tertiary grinding disc 52 are sequentially arranged. The primary grinding disc 32, the secondary grinding disc 42, and the tertiary grinding disc 52 are all fixedly connected to the rotating shaft 21. Specifically, the rotating shaft 21 passes through the center of the primary grinding disc 32, the secondary grinding disc 42, and the tertiary grinding disc 52, thereby causing the primary grinding disc 32, the secondary grinding disc 42, and the tertiary grinding disc 52 to rotate under the drive of the rotating shaft 21, thereby grinding and dispersing the slurry inside the grinding cylinder 1. Furthermore, the interior of the grinding cylinder 1 is divided into a primary grinding space 31, a secondary grinding space 41, a tertiary grinding space 51, and a slurry buffer space 6 by a primary grinding disc 32, a secondary grinding disc 42, and a tertiary grinding disc 52. The primary grinding space 31, the secondary grinding space 41, and the tertiary grinding space 51 are respectively filled with primary grinding balls 33, secondary grinding balls 43, and tertiary grinding balls 53, thereby grinding and dispersing the slurry step by step.

[0034] In this embodiment, the secondary grinding disc 42 is taken as an example, and its structure is detailed in [reference needed]. Figure 2 and Figure 3The surface of the secondary grinding disc 421 is covered with through holes 421, facilitating the screening and transfer of the ground slurry from the previous grinding space to the next grinding space. Reinforcing ribs 422 are provided on its surface, penetrating the center of the secondary grinding disc 42 and symmetrical about the center of the secondary grinding disc 42. Vertical protrusions 423 are provided at both ends of the reinforcing ribs 422. As the secondary grinding disc 42 rotates, the reinforcing ribs 422 and the protrusions 423 can drive the secondary grinding balls 43, thereby fully grinding and dispersing the slurry in the secondary grinding space 41, enhancing the grinding effect. It is understood that the number of reinforcing ribs 422 is not particularly limited and can be set as needed. In this embodiment, three sets of reinforcing ribs 422 are evenly distributed on the surface of the secondary grinding disc 42. The structures of the primary grinding disc 32 and the tertiary grinding disc 52 are similar to those of the secondary grinding disc 42, and will not be described in detail here.

[0035] In this embodiment, the primary grinding disc 32, secondary grinding disc 42, and tertiary grinding disc 52 are of different sizes and gradually increase in size from the feed inlet 11 to the discharge outlet 12. This design ensures that large particles in the slurry do not skip the through holes on the grinding discs and flow into the next grinding space, while also achieving a more uniform grinding effect. Furthermore, the diameter of the through holes on the grinding discs is smaller than that of the primary grinding balls 33, secondary grinding balls 43, and tertiary grinding balls 53, thereby preventing grinding balls of different sizes from flowing into different grinding spaces, which would result in uneven grinding ball sizes within the spaces and ensure the grinding effect. At the same time, the gradually decreasing diameter of the through holes also increases the speed at which the slurry enters the next grinding space, preventing machine blockage. Furthermore, the accommodating space of the primary grinding space 31, the secondary grinding space 41, and the tertiary grinding space 51 gradually decreases from the feed inlet 11 to the discharge outlet 12. At the same time, the diameters of the primary grinding balls 33, the secondary grinding balls 43, and the tertiary grinding balls 53 also gradually decrease. The purpose is to effectively pre-grind, coarsely grind, and finely process slurries of different particle sizes using grinding balls of different sizes. The specific size of the grinding balls can be reasonably designed according to the distribution of the grinding spaces. Those skilled in the art have the ability to do so. For example, in this embodiment, the diameter of the primary grinding ball 33 is 5-10 mm, the diameter of the secondary grinding ball 43 is 2-5 mm, and the diameter of the tertiary grinding ball 53 is 1-2 mm. At the same time, providing grinding spaces of different sizes ensures that grinding balls of different sizes can effectively grind the slurry, while improving the utilization rate of the grinding spaces.

[0036] The following description of the working process of the lithium iron phosphate slurry pre-grinding device in the above embodiments will provide a clearer introduction to the pre-grinding device.

[0037] The mixed lithium iron phosphate slurry is pumped into the grinding cylinder 1 through the feed port 11. The slurry first enters the primary grinding space 31. Simultaneously, the drive mechanism 2 is activated, and the rotating shaft 21 begins to rotate under the action of the drive mechanism 2, driving the primary grinding disc 32, the secondary grinding disc 42, and the tertiary grinding disc 52 to rotate. The reinforcing ribs and protrusions on the surface of the grinding discs drive the grinding balls in the corresponding grinding spaces to rotate. The primary grinding balls 33, secondary grinding balls 43, and tertiary grinding balls 53 generate shearing and frictional forces, thoroughly grinding and dispersing the slurry entering the corresponding grinding spaces. The ground slurry is screened and flows through the through holes on the grinding discs, sequentially flowing through the primary grinding space 31, the secondary grinding space 41, and the tertiary grinding space 51, and finally stored in the slurry buffer space 6 to await discharge, and finally discharged from the grinding cylinder 1 through the discharge port 12.

[0038] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A pre-grinding device for lithium iron phosphate slurry, characterized in that, include: A grinding cylinder, wherein a lithium iron phosphate slurry inlet and an outlet are respectively provided on opposite sides of the grinding cylinder; Several grinding discs are located inside the grinding cylinder and are arranged sequentially from the feed inlet to the discharge outlet, dividing the grinding cylinder into several grinding spaces and a slurry buffer space. The grinding spaces are filled with grinding media. The grinding disc has a reinforcing rib running through its center on its surface, and the two ends of the reinforcing rib have protrusions.

2. The lithium iron phosphate slurry pre-grinding device as described in claim 1, characterized in that, There are three grinding discs.

3. The lithium iron phosphate slurry pre-grinding device as described in claim 1, characterized in that, The surface of the grinding disc is covered with through holes, and the diameter of the through holes is smaller than the diameter of the grinding media.

4. The lithium iron phosphate slurry pre-grinding device as described in claim 3, characterized in that, From the feed inlet to the discharge outlet, the diameter of the through holes on the surface of the grinding disc decreases step by step.

5. The lithium iron phosphate slurry pre-grinding device as described in claim 1, characterized in that, The size of the grinding disc increases progressively from the feed inlet to the discharge outlet.

6. The lithium iron phosphate slurry pre-grinding device as described in claim 1, characterized in that, From the feed inlet to the discharge outlet, the diameter of the grinding media in the grinding space gradually decreases.

7. The lithium iron phosphate slurry pre-grinding device as described in claim 1, characterized in that, From the feed inlet to the discharge outlet, the capacity of the grinding space and the slurry buffer space decreases progressively.

8. The lithium iron phosphate slurry pre-grinding device as described in claim 1, characterized in that, The reinforcing ribs consist of three sets.

9. The lithium iron phosphate slurry pre-grinding apparatus according to any one of claims 1-8, characterized in that, The lithium iron phosphate slurry pre-grinding device also includes a driving mechanism, which is located on the side of the grinding cylinder.

10. The lithium iron phosphate slurry pre-grinding device as described in claim 9, characterized in that, The drive mechanism is equipped with a rotating shaft that extends into the interior of the grinding cylinder and passes through the center of the grinding disc, and is fixedly connected to the grinding disc.

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