Lithium iron phosphate slurry preparation device

Abstract

This utility model discloses a lithium iron phosphate slurry preparation device, including multiple grinding mechanisms connected in series. Each grinding mechanism includes grinding components and screening components. The grinding precision of the multiple grinding components gradually increases along the series direction. The screening component has a feed inlet, a return inlet, and a discharge outlet. The feed inlet is connected to the discharge end of the grinding component. The return inlet and discharge outlet are used to discharge materials with particle sizes larger than and smaller than a set value, respectively. The return inlet is connected to the feed end of the grinding component, and the discharge outlet is connected to the feed end of the grinding component in the next grinding mechanism in the series. By connecting the grinding mechanisms in series, continuous production of lithium iron phosphate slurry is achieved, avoiding performance fluctuations between batches. Furthermore, by setting a screening component in each grinding mechanism, the grinding precision of each stage can be controlled, allowing for precise control of the abrasive particle size.

Description

Technical Field

[0001] This utility model relates to the field of lithium iron phosphate slurry preparation technology, and specifically to a lithium iron phosphate slurry preparation device. Background Technology

[0002] As the mainstream cathode material for lithium-ion batteries, the sand milling process is a key step affecting the material's performance during its preparation.

[0003] Currently, the grinding process in the preparation of lithium iron phosphate slurry uses multi-stage dispersed grinding equipment.

[0004] Multi-stage, decentralized grinding equipment shuts down after each grinding cycle and restarts for the next cycle, requiring frequent start-stop operations. This results in uneven particle size distribution in different batches of slurry, making continuous production impossible. Utility Model Content

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a lithium iron phosphate slurry preparation device to solve the technical problem that the grinding device in the existing lithium iron phosphate slurry preparation device needs to be frequently started and stopped, resulting in uneven particle size distribution of slurry processed in different batches and making it impossible to achieve continuous production.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] This utility model provides a lithium iron phosphate slurry preparation apparatus, comprising:

[0008] Multiple grinding mechanisms connected in series, each grinding mechanism including a grinding component and a screening component, wherein the grinding precision of the multiple grinding components gradually increases along the series direction, and the screening component has a feed inlet, a return inlet and a discharge outlet, wherein the feed inlet is connected to the discharge end of the grinding component, and the return inlet and discharge outlet are respectively used to discharge materials with particle sizes larger than a set value and smaller than a set value, respectively, wherein the return inlet is connected to the feed end of the grinding component, and the discharge outlet is connected to the feed end of the grinding component in the next grinding mechanism connected in series.

[0009] In one embodiment, the grinding mechanism further includes a first mixing tank and a feed pump, wherein the feed pump has its inlet end connected to the first mixing tank and its outlet end connected to the feed end of the grinding assembly.

[0010] In one embodiment, the grinding mechanism further includes a heat exchanger having a material flow channel and a coolant flow channel capable of heat exchange, the material flow channel being disposed on the communication path between the first mixing tank and the feed pump.

[0011] In one embodiment, the grinding mechanism further includes a second mixing tank, which is connected to the discharge end of the grinding assembly, and the feed inlet is connected to the second mixing tank and, via the second mixing tank, to the grinding assembly.

[0012] In one embodiment, the return port is connected to the first mixing tank and, via the first mixing tank, to the feed end of the grinding assembly.

[0013] In one embodiment, the grinding mechanism further includes a first iron remover and a second iron remover, wherein the first iron remover is disposed on the communication path between the first mixing tank and the feed pump, and the second iron remover is disposed on the communication path between the grinding assembly and the second mixing tank.

[0014] In one embodiment, the lithium iron phosphate slurry preparation apparatus further includes a storage tank connected to the discharge port in the grinding mechanism at the end.

[0015] In one embodiment, the lithium iron phosphate slurry preparation apparatus further includes a raw material mechanism, which includes multiple raw material storage components and a mixing tank. The inlet end of the mixing tank is connected to the outlet ends of the multiple raw material storage components, and the outlet end of the mixing tank is connected to the inlet end of the grinding component in the first grinding mechanism.

[0016] In one embodiment, the raw material storage assembly includes a raw material storage bin, a metering bin, a screw feeder, a dissolving tank, and a metering pump connected in sequence, with the discharge end of the metering pump connected to the mixing tank.

[0017] In one embodiment, the raw material mechanism further includes a buffer tank, and the discharge end of the mixing tank is an overflow port located in the mixing tank. The overflow port is connected to the buffer tank and is connected via the buffer tank to the feed end of the grinding component in the first grinding mechanism.

[0018] Compared with the prior art, the lithium iron phosphate slurry preparation device provided by this utility model has the following steps: the lithium iron phosphate slurry enters the grinding component of the first grinding mechanism, the grinding component grinds the lithium iron phosphate slurry, the ground lithium iron phosphate slurry enters the screening component, the lithium iron phosphate slurry with qualified particle size in the screening component enters the grinding component of the next grinding mechanism, and the particle size of the lithium iron phosphate slurry is further refined. The lithium iron phosphate slurry with unqualified particle size in the screening component returns to the feed end of the grinding component from the return port, and is ground again by the grinding component to control the particle size of the outflowing lithium iron phosphate slurry.

[0019] By connecting the grinding mechanisms in series, continuous production of lithium iron phosphate slurry can be achieved, avoiding performance fluctuations between batches. At the same time, by setting a screening component in each grinding mechanism, the grinding precision of each stage can be controlled, and the particle size of the slurry can be precisely controlled. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a lithium iron phosphate slurry preparation device provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the grinding mechanism in a lithium iron phosphate slurry preparation device provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the raw material mechanism in a lithium iron phosphate slurry preparation device according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the raw material storage component in a lithium iron phosphate slurry preparation device provided in an embodiment of this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] Grinding mechanism 1; grinding assembly 11; screening assembly 12; feed inlet 12a; return inlet 12b; discharge inlet 12c; first mixing tank 13; feed pump 14; heat exchanger 15; second mixing tank 16; first iron separator 17; second iron separator 18;

[0026] Storage tank 2;

[0027] Raw material mechanism 3; raw material storage component 31; raw material storage bin 311; metering bin 312; screw feeder 313; dissolving tank 314; metering pump 315; mixing tank 32; buffer tank 33. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0029] To address the technical problem of frequent start-ups and shutdowns of the grinding device in lithium iron phosphate slurry preparation equipment, which leads to uneven particle size distribution in different batches of slurry and prevents continuous production, this invention provides a lithium iron phosphate slurry preparation device that enables continuous production of lithium iron phosphate slurry and avoids the problem of uneven particle size distribution.

[0030] Please see Figure 1 , Figure 1This is a schematic diagram of the structure of a lithium iron phosphate slurry preparation device in one embodiment of the present invention. The lithium iron phosphate slurry preparation device includes multiple grinding mechanisms 1 connected in series. Each grinding mechanism 1 includes a grinding component 11 and a screening component 12. The grinding precision of the multiple grinding components 11 gradually increases along the series direction. The screening component 12 has a feed inlet 12a, a return inlet 12b, and a discharge inlet 12c. The feed inlet 12a is connected to the discharge end of the grinding component 11. The return inlet 12b and the discharge inlet 12c are used to discharge materials with particle sizes greater than a set value and smaller than a set value, respectively. The return inlet 12b is connected to the feed end of the grinding component 11, and the discharge inlet 12c is connected to the feed end of the grinding component 11 in the next grinding mechanism 1 connected in series.

[0031] Specifically, the lithium iron phosphate slurry enters the grinding component 11 of the first grinding mechanism 1, where the grinding component 11 grinds the lithium iron phosphate slurry. The ground lithium iron phosphate slurry then enters the screening component 12. The lithium iron phosphate slurry with qualified particle size in the screening component 12 enters the grinding component 11 of the next grinding mechanism 1 for further refinement of the particle size. The lithium iron phosphate slurry with unqualified particle size in the screening component 12 returns to the feed end of the grinding component 11 from the return port 12b, and is ground again by the grinding component 11 to control the particle size of the outflowing lithium iron phosphate slurry.

[0032] By connecting the grinding mechanisms 1 in series, continuous production of lithium iron phosphate slurry can be achieved, avoiding performance fluctuations between batches. At the same time, by setting a screening component 12 in each grinding mechanism 1, the grinding precision of each stage can be controlled, and the particle size of the slurry can be precisely controlled.

[0033] It should be understood that the number of grinding mechanisms 1 can be two, three, four, etc., and the grinding assembly 11 can be a horizontal sand mill, ball mill, three-roll mill, etc., and the screening assembly 12 can be a centrifugal vibrating screen, ultrasonic vibrating screen, etc. Specifically, such as Figure 1 As shown, in one embodiment, the number of grinding mechanisms 1 is three, the grinding component 11 is a sand mill, and the diameter of the zirconium balls used in the three sand mills decreases sequentially to adjust the grinding accuracy of the three sand mills. Grinding accuracy refers to the particle size of the ground particles. The higher the accuracy, the smaller the particle size. The screening component 12 is a dynamic centrifugal classifier.

[0034] It should be understood that the grinding component 11 can be directly fed with lithium iron phosphate slurry, specifically, as shown in the example below. Figure 2 As shown, in one embodiment, the grinding mechanism 1 further includes a first mixing tank 13 and a feed pump 14, with the feed end of the feed pump 14 connected to the first mixing tank 13 and the discharge end connected to the feed end of the grinding assembly 11.

[0035] Specifically, the slurry first enters the first mixing tank 13 for buffering and initial dispersion / homogenization. The feed pump 14 stably and controllably draws the slurry from the first mixing tank 13 and delivers it to the inlet of the grinding assembly 11. The first mixing tank 13 provides buffering, making the feed more stable, while allowing for initial mixing. The feed pump 14 ensures that the slurry enters the grinding zone at a constant pressure and flow rate, avoiding equipment overload or idling, and improving grinding efficiency and uniformity.

[0036] It should be understood that the feed pump 14 can be a diaphragm pump, a metering pump, etc.

[0037] In order to cool the lithium iron phosphate slurry entering the first grinding unit 1, for this purpose, such as Figure 2 As shown, in one embodiment, the grinding mechanism 1 further includes a heat exchanger 15, which has a material flow channel and a coolant flow channel capable of heat exchange. The material flow channel is located on the communication path between the first mixing tank 13 and the feed pump 14.

[0038] In this embodiment, a heat exchanger 15 is provided on the communication path between the first mixing tank 13 and the feed pump 14. Cooling liquid is introduced into the cooling channel of the heat exchanger 15. When the lithium iron phosphate slurry passes through the heat exchanger 15, heat exchange can be performed on the lithium iron phosphate slurry to reduce the temperature of the lithium iron phosphate slurry, so that the temperature of the lithium iron phosphate slurry is within the set range, thus avoiding the degradation of temperature-sensitive materials.

[0039] It should be understood that the heat exchanger 15 can be a plate heat exchanger 15, a shell and tube heat exchanger 15, etc.

[0040] In order to buffer the feed to the screening assembly 12, for this purpose, such as Figure 2 As shown, in one embodiment, the grinding mechanism 1 further includes a second mixing tank 16, which is connected to the discharge end of the grinding assembly 11, and the feed inlet 12a is connected to the second mixing tank 16 and, via the second mixing tank 16, to the grinding assembly 11. It should be understood that the discharge end of the grinding assembly 11 can be directly connected to the feed inlet 12a of the screening assembly 12.

[0041] The slurry exiting the grinding chamber may exhibit short-term inhomogeneity or pulsation. The second mixing tank 16 provides a buffer and, through slow agitation, ensures that the ground slurry is more uniform and stable before entering the screening process.

[0042] It should be understood that the return port 12b can be directly connected to the feed end of the grinding assembly 11, or it can be connected to the feed end of the grinding assembly 11 through other devices, such as buffer tank 33, circulation pump, etc. Specifically, in one embodiment, the return port 12b is connected to the first mixing tank 13, and is connected to the feed end of the grinding assembly 11 through the first mixing tank 13.

[0043] Specifically, by thoroughly mixing the coarse material with the new feed in the first mixing tank 13, a uniform slurry is ensured to enter the grinding process, avoiding localized over-concentration or blockage; this ensures that all coarse particles are returned to the machine for re-grinding, reducing waste.

[0044] The grinding process can easily introduce magnetic foreign objects, such as iron filings, resulting in a magnetic material content in the finished product exceeding 50 ppm. Therefore, such as... Figure 2 As shown, in one embodiment, the grinding mechanism 1 further includes a first iron remover 17 and a second iron remover 18. The first iron remover 17 is disposed on the communication path between the first mixing tank 13 and the feed pump 14, and the second iron remover 18 is disposed on the communication path between the grinding assembly 11 and the second mixing tank 16.

[0045] The first iron separator 17 is installed on the pipeline from the outlet of the first mixing tank 13 to the inlet of the feed pump 14, or on the pipeline from the outlet of the feed pump 14 to the grinding inlet. It removes ferromagnetic impurities before entering the grinding stage and protects the grinding core components from the hard impact and wear of large iron particles brought in by the raw materials. The second iron separator 18 is installed on the pipeline from the outlet of the grinding component 11 to the second mixing tank 16 (or the screening inlet). It removes ferromagnetic impurities that may be introduced by the wear of the grinding component 11 after the grinding stage and before screening.

[0046] It should be understood that the first iron separator 17 and the second iron separator 18 can be electromagnetic iron separators, permanent magnet self-unloading iron separators, etc.

[0047] In order to collect the final lithium iron phosphate slurry product formed by grinding, therefore, as follows Figure 2 As shown, in one embodiment, the lithium iron phosphate slurry preparation device further includes a storage tank 2, which is connected to the discharge port 12c in the end grinding mechanism 1.

[0048] The first iron remover 17 connects the screening discharge port 12c of the tail grinding mechanism 1 to the inlet of the storage tank 2, where the finished lithium iron phosphate slurry is collected as a buffer storage for the final product, balancing the production rhythm of the front grinding and the back coating processes.

[0049] In order to supply the raw materials for lithium iron phosphate slurry, therefore, such as Figure 3 As shown, in one embodiment, the lithium iron phosphate slurry preparation apparatus further includes a raw material mechanism 3, which includes multiple raw material storage components 31 and a mixing tank 32. The inlet end of the mixing tank 32 is connected to the outlet end of the multiple raw material storage components 31, and the outlet end of the mixing tank 32 is connected to the inlet end of the grinding component 11 in the first grinding mechanism 1.

[0050] Multiple raw materials are stored in their respective independent raw material storage components 31 and introduced into the mixing tank 32 according to a preset ratio. They are mixed in the mixing tank 32, where preliminary low-shear stirring and mixing are carried out to form an initial, relatively uniform, and unrefined lithium iron phosphate slurry. The discharge port of the mixing tank 32 is connected to the feed end of the grinding component 11 of the first grinding mechanism 1. The various raw materials are initially mixed evenly in the low-shear mixing tank 32, laying a good foundation for subsequent efficient grinding and dispersion. This avoids some materials being difficult to enter the grinding stage or being ground unevenly due to uneven premixing, and provides a stable and qualified premixed material input for subsequent grinding processes.

[0051] It should be understood that the number of raw material storage components 31 can be designed accordingly based on the type of raw material required, specifically, such as... Figure 3 As shown, in one embodiment, there are four raw material storage components 31, which respectively store iron sulfate, lithium source, carbon source, dispersant, etc., wherein the lithium source can be lithium carbonate, the carbon source can be glucose or sucrose, and the dispersant can be polyethylene glycol.

[0052] In order to ensure that all raw materials can be fully dissolved, therefore, such as Figure 3 As shown, in one embodiment, the raw material storage assembly 31 includes a raw material storage bin 311, a metering bin 312, a screw feeder 313, a dissolving tank 314, and a metering pump 315 connected in sequence. The discharge end of the metering pump 315 is connected to the mixing tank 32.

[0053] Raw materials are stored in the raw material storage bin 311. The raw materials enter the metering bin 312 for metering. The screw feeder 313 continuously feeds the raw materials from the metering bin 312 into the solvent tank. The raw materials are mixed and dissolved with pure water in the dissolving tank 314. The dissolved raw materials are pumped into the mixing tank 32 by the metering pump 315. Each metering pump 315 pumps the raw materials into the mixing tank 32 according to a preset ratio. Through the metering bin 312, screw feeder, and metering pump 315, a high-precision ratio of various raw materials is achieved, ensuring the accuracy of the slurry basic formula.

[0054] To ensure the mixing effect of mixing tank 32 and the stable feeding of grinding mechanism 1, therefore, as follows: Figure 3 As shown, in one embodiment, the raw material mechanism 3 further includes a buffer tank 33, and the discharge end of the mixing tank 32 is an overflow port provided in the mixing tank 32. The overflow port is connected to the buffer tank 33 and is connected to the feed end of the grinding component 11 in the first grinding mechanism 1 through the buffer tank 33.

[0055] The overflow port design forces the raw materials in the mixing tank 32 to be completely agitated and mixed for a period of time before flowing out, which significantly improves the uniformity of the initial premixed slurry. The buffer tank 33 serves as the feed buffer tank 33 of the grinding mechanism 1, ensuring that the feed flow and pressure to the first-stage grinding mechanism 1 are more stable and will not be affected by the short-term fluctuations of the upstream batching.

[0056] Specifically, in one embodiment, in order to control the discharge particle size of each grinding component 11, the grinding mechanism 1 further includes an online particle size analyzer (not shown in the figure). The online particle size analyzer is set at the discharge end of the grinding component 11 and is used to detect the discharge particle size of the grinding component 11. At the same time, it is connected to the feed pump 14 through a PLC controller (not shown in the figure). When the online particle size analyzer detects that the particle size exceeds the set value, the PLC controller controls the feed pump 14 to reduce the feeding speed.

[0057] The specific embodiments of this utility model described above do not constitute a limitation on the scope of protection of this utility model. Any other corresponding changes and modifications made based on the technical concept of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A lithium iron phosphate slurry preparation apparatus, characterized in that, include: Multiple grinding mechanisms connected in series, each grinding mechanism including a grinding component and a screening component, wherein the grinding precision of the multiple grinding components gradually increases along the series direction, and the screening component has a feed inlet, a return inlet and a discharge outlet, wherein the feed inlet is connected to the discharge end of the grinding component, and the return inlet and discharge outlet are respectively used to discharge materials with particle sizes larger than a set value and smaller than a set value, respectively, wherein the return inlet is connected to the feed end of the grinding component, and the discharge outlet is connected to the feed end of the grinding component in the next grinding mechanism connected in series.

2. The lithium iron phosphate slurry preparation apparatus according to claim 1, characterized in that, The grinding mechanism further includes a first mixing tank and a feed pump, wherein the feed pump has its inlet end connected to the first mixing tank and its outlet end connected to the feed end of the grinding assembly.

3. The lithium iron phosphate slurry preparation apparatus according to claim 2, characterized in that, The grinding mechanism also includes a heat exchanger, which has a material flow channel and a coolant flow channel capable of heat exchange. The material flow channel is located on the communication path between the first mixing tank and the feed pump.

4. The lithium iron phosphate slurry preparation apparatus according to claim 2, characterized in that, The grinding mechanism further includes a second mixing tank, which is connected to the discharge end of the grinding assembly. The feed inlet is connected to the second mixing tank and, through the second mixing tank, to the grinding assembly.

5. The lithium iron phosphate slurry preparation apparatus according to claim 4, characterized in that, The return port is connected to the first mixing tank, and is connected to the feed end of the grinding assembly via the first mixing tank.

6. The lithium iron phosphate slurry preparation apparatus according to claim 4, characterized in that, The grinding mechanism further includes a first iron remover and a second iron remover. The first iron remover is disposed on the communication path between the first mixing tank and the feed pump, and the second iron remover is disposed on the communication path between the grinding assembly and the second mixing tank.

7. The lithium iron phosphate slurry preparation apparatus according to claim 1, characterized in that, It also includes a storage tank, which is connected to the discharge port in the grinding mechanism at the end.

8. The lithium iron phosphate slurry preparation apparatus according to claim 1, characterized in that, It also includes a raw material mechanism, which includes multiple raw material storage components and a mixing tank. The inlet of the mixing tank is connected to the outlet of the multiple raw material storage components, and the outlet of the mixing tank is connected to the inlet of the grinding component in the first grinding mechanism.

9. The lithium iron phosphate slurry preparation apparatus according to claim 8, characterized in that, The raw material storage assembly includes a raw material storage bin, a metering bin, a screw feeder, a dissolving tank, and a metering pump connected in sequence, with the discharge end of the metering pump connected to the mixing tank.

10. The lithium iron phosphate slurry preparation apparatus according to claim 8, characterized in that, The raw material mechanism also includes a buffer tank. The discharge end of the mixing tank is an overflow port located in the mixing tank. The overflow port is connected to the buffer tank and is connected to the feed end of the grinding component in the first grinding mechanism via the buffer tank.

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