Microgravity granulation equipment for synthesizing positive electrode material

Abstract

The utility model relates to the technical field of anode material processing equipment, and discloses microgravity granulation equipment for anode material synthesis, which comprises a tower body, and a channel falling along the gravity direction is arranged in the tower body; the atomizing nozzle is arranged at the top of the tower body; the heat radiation heating device is arranged on the side wall of the tower body; and the vacuum system is connected with the tower body and is used for maintaining the vacuum degree in the tower body. According to the equipment, a high-vacuum-degree environment is constructed, a specific falling stroke is combined, and the surface tension spontaneous shrinkage effect of liquid drops in a simulated microgravity state is utilized, so that positive electrode material precursor particles with high sphericity, high stacking density and a compact internal structure can be prepared.

Description

Technical Field

[0001] This utility model relates to the technical field of cathode material processing equipment, specifically to a microgravity granulation device for cathode material synthesis. Background Technology

[0002] Phosphate-based cathode materials (lithium iron phosphate, lithium manganese iron phosphate, lithium sodium iron phosphate, etc.) are the core cathode materials for lithium-ion batteries, and their morphology control directly determines the battery's packing density, electrolyte wettability, and rate performance. Currently, the main equipment and methods used in industry to prepare lithium iron phosphate particles fall into the following two categories:

[0003] (1) Traditional atmospheric pressure spray drying granulation: In existing technologies, spray drying towers under atmospheric pressure are commonly used for granulation. The working principle is to atomize the slurry using high-speed centrifugal force or pressure nozzles, and then evaporate the moisture under the blowing of hot air at atmospheric pressure. However, this type of equipment has the following structural defects:

[0004] I. Morphological distortion: Under normal pressure, the droplets experience greater air resistance as they fall, and the hot air does not contact the droplets evenly, causing the droplet surface to dry too quickly and form a hard shell. When the internal vapor pressure accumulates, it is easy to burst or collapse, eventually generating a large number of hollow spheres or irregular particles.

[0005] II. Low packing density: Due to the irregularity of the particles, the geometric packing efficiency during electrode coating is extremely low, resulting in the material's packing density usually being difficult to exceed 1.6 g / cm³.

[0006] (2) Mechanical stirring granulation or disc granulation: This common technique utilizes the shear force generated by mechanical stirring to combine powder and binder into spheres. The disadvantage of this method is:

[0007] I. Uneven particle size distribution: Mechanical granulation makes it difficult to precisely control the particle diameter, resulting in significant differences in particle size and affecting the consistency of electrochemical performance;

[0008] II. Poor particle density: Due to the lack of effective external centripetal force induction, the primary particles inside the particles are loosely arranged, resulting in unsatisfactory compaction density and electrical conductivity.

[0009] Therefore, there is a lack of a dedicated granulation device in the existing technology that can granulate cathode material slurry into highly spherical particles. Utility Model Content

[0010] The purpose of this invention is to overcome the problems of poor particle morphology and low bulk density of cathode materials caused by gravity and atmospheric pressure air resistance in existing granulation equipment.

[0011] To achieve the above objectives, this utility model provides a microgravity granulation device for the synthesis of cathode materials, comprising:

[0012] The tower body, with an internal channel for falling along the direction of gravity;

[0013] Atomizing nozzles are disposed at the top of the tower body;

[0014] A thermal radiation heating device is installed on the side wall of the tower body;

[0015] A vacuum system, connected to the tower body, is used to maintain the vacuum level inside the tower body.

[0016] As a further improvement to the above technical solution:

[0017] Preferably, the tower body is provided with a vertical drop channel, and the effective drop height of the channel is 1.5m-3m.

[0018] Preferably, the nozzle orifice diameter of the atomizing nozzle is 10μm-100μm.

[0019] Preferably, the thermal radiation heating device is an infrared heater, which is arranged around the side wall of the tower body (1).

[0020] Preferably, the infrared heaters are arranged in sections along the height of the tower, and the heating temperature of each section of the infrared heater is independently adjustable.

[0021] Preferably, the vacuum system includes a vacuum pump assembly and a vacuum interface connected to the side wall of the tower body, and the vacuum system is capable of maintaining the vacuum level inside the tower body at -0.095MPa to -0.098MPa.

[0022] Preferably, the bottom of the tower body is provided with a particle collection chamber, which is used to receive secondary particles that have fallen freely and been dried.

[0023] Preferably, a pressure sensor is also provided at the top of the tower body. The pressure sensor is electrically connected to the controller of the vacuum system and is used to monitor and adjust the vacuum level inside the tower in real time.

[0024] Preferably, the front end of the atomizing nozzle is also connected to a slurry conveying system.

[0025] Preferably, the side wall of the tower body is also provided with an observation window, which is used to monitor the free fall and spherical shrinkage state of the droplets after being atomized by the atomizing nozzle in the tower body.

[0026] The microgravity granulation equipment for cathode material synthesis provided by this invention can produce cathode material precursor particles with high sphericity, high packing density and compact internal structure by constructing a high vacuum environment and combining it with a specific falling stroke, and utilizing the spontaneous contraction effect of surface tension of droplets under simulated microgravity. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a microgravity granulation device for synthesizing cathode materials according to a specific embodiment of this utility model;

[0028] Figure 2 This is a schematic diagram of the structure of an atomizing nozzle provided in a specific embodiment of this utility model;

[0029] Figure 3 This is a schematic diagram of the structure of a microgravity granulation device for synthesizing cathode materials provided in another specific embodiment of this utility model.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. Tower body; 2. Atomizing nozzle; 3. Thermal radiation heating device; 4. Vacuum system; 5. Particle collection bin; 6. Slurry conveying system; 7. Observation window. Detailed Implementation

[0032] To make the technical problems, technical solutions, and beneficial effects 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.

[0033] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0035] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "higher than", "lower than", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and 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. Therefore, they should not be construed as limitations on this utility model.

[0036] like Figure 1 As shown, this embodiment provides a microgravity granulation device for the synthesis of cathode materials, characterized in that it includes:

[0037] Tower body 1, wherein the interior of tower body 1 is provided with a channel for falling along the direction of gravity;

[0038] Atomizing nozzle 2 is disposed at the top of the tower body 1; used to atomize the positive electrode material precursor slurry into droplets of the required particle size, which then fall from the channel of the tower body along the direction of gravity.

[0039] A thermal radiation heating device 3 is installed on the side wall of the tower body 1; it is used to heat the droplets falling along the direction of gravity in the channel to remove the solvent and achieve the effect of drying and granulation.

[0040] And a vacuum system 4, connected to the tower body 1, is used to maintain the vacuum level inside the tower body 1 to simulate microgravity and create a low-resistance environment.

[0041] This invention provides a microgravity granulation device for the synthesis of cathode materials. By constructing a high-vacuum environment and combining it with a specific falling stroke, the device utilizes the spontaneous contraction effect of surface tension in simulated microgravity to cause the droplets to spontaneously contract into near-spherical shapes. Simultaneously, thermal radiation heating combined with a stable vacuum ensures uniform drying of the precursor particles, avoiding the cracking problems commonly found in traditional spray drying. The spherical cathode material particles prepared by this device are tightly packed, resulting in a bulk density of ≥1.8 g / cm³ for the finished cathode material.

[0042] It should be noted that, in this application, the cathode material includes, but is not limited to, any one of lithium iron phosphate, lithium manganese iron phosphate, lithium manganese phosphate, and lithium sodium iron phosphate.

[0043] According to some preferred embodiments of this invention, the effective drop height of the channel is 1.5m-3m. Since the droplets rapidly lose moisture during free fall, the higher the height, the longer the "flight time" of the droplets in the thermal field, thus ensuring that the secondary particles have reached the expected degree of dryness when they reach the bottom, forming spherical precursor particles.

[0044] According to some preferred embodiments of the present invention, the nozzle orifice diameter of the atomizing nozzle 2 is 10μm-100μm. More preferably, such as... Figure 2 As shown, there are multiple atomizing nozzles 2, and the specific number is determined according to actual production needs. For example, the number of atomizing nozzles 2 is 10, 100, or 1000.

[0045] According to some more preferred embodiments of the present invention, the plurality of atomizing nozzles 2 have the same aperture size and are used to synthesize and produce positive electrode materials with the same particle size.

[0046] According to some more preferred embodiments of the present invention, the aperture sizes of the plurality of atomizing nozzles 2 are different to meet the requirements of particle size distribution of positive electrode materials in actual production, and to synthesize positive electrode materials with different particle sizes.

[0047] According to some preferred embodiments of the present invention, the atomizing nozzle 2 is a pressure atomizing nozzle.

[0048] According to some preferred embodiments of the present invention, the thermal radiation heating device 3 is an infrared heater, which is arranged around the side wall of the tower body 1. More preferably, the infrared heater is arranged in segments along the height direction of the tower body 1, and the heating temperature of each segment of the infrared heater is independently adjustable, with a temperature adjustment range of 100℃-300℃.

[0049] According to some preferred embodiments of the present invention, the vacuum system 4 includes a vacuum pump assembly and a vacuum interface connected to the side wall of the tower body 1. The vacuum system 4 can maintain the vacuum level inside the tower body 1 at -0.095MPa to -0.098MPa.

[0050] According to some preferred embodiments of the present invention, such as Figure 3 As shown, the bottom of the tower body 1 is provided with a particle collection bin 5, which is used to receive secondary particles that have fallen freely and been dried. More preferably, the particle collection bin 5 is a conical receiving bin, and the bottom of the conical receiving bin is connected to an airlock discharge valve. When it is necessary to discharge the secondary particles, the air supply pressure is reduced, causing the secondary particles to flow through the valve outlet.

[0051] According to some preferred embodiments of the present invention, a pressure sensor is also provided at the top of the tower body 1. The pressure sensor is electrically connected to the controller of the vacuum system 4 and is used to monitor and adjust the vacuum level inside the tower in real time.

[0052] According to some preferred embodiments of the present invention, such as Figure 3As shown, the front end of the atomizing nozzle 2 is also connected to a slurry delivery system 6. More preferably, the slurry delivery system includes a slurry storage tank and a delivery pump connected in sequence. The slurry storage tank is used to store the cathode material precursor slurry, and the delivery pump is used to deliver the cathode material precursor slurry to the atomizing nozzle 2.

[0053] According to some preferred embodiments of the present invention, such as Figure 3 As shown, the side wall of the tower body 1 is also provided with an observation window 7, which is used to monitor the free fall and spherical contraction state of the droplets after atomization by the atomizing nozzle 2 in the tower body 1. More preferably, the observation window 7 is made of high-temperature resistant quartz glass and is sealed to the observation hole of the tower body 1 by flange fasteners.

[0054] like Figure 3 As shown, this utility model provides a specific microgravity granulation device for the synthesis of lithium iron phosphate cathode materials, comprising:

[0055] Tower body 1, the tower body 1 has an internal channel for falling along the direction of gravity, the effective falling height of the channel is 2m;

[0056] Atomizing nozzle 2 is disposed at the top of the tower body 1. The nozzle orifice diameter of the atomizing nozzle 2 is 50μm and the number of nozzles is 1000.

[0057] The thermal radiation heating device 3 is an infrared heater, which is arranged around the side wall of the tower body 1 to heat the precursor slurry droplets falling along the direction of gravity in the channel. The temperature adjustment range of the infrared heater is 100℃-300℃.

[0058] And a vacuum system 4, connected to the tower body 1, the vacuum system 4 includes a vacuum pump group and a vacuum interface connected to the side wall of the tower body 1, the vacuum system 4 can maintain the vacuum degree inside the tower body 1 at -0.095MPa to -0.098MPa;

[0059] Particle collection chamber 5 is located at the bottom of the tower body 1 and is used to receive secondary particles that have fallen freely and been dried.

[0060] The slurry conveying system 6 includes a slurry storage tank and a conveying pump connected in sequence. The slurry storage tank is used to store the cathode material precursor slurry, and the conveying pump is also connected to the atomizing nozzle 2 to convey the cathode material precursor slurry to the atomizing nozzle 2.

[0061] The observation window 7, made of high-temperature resistant quartz glass, is located on the side wall of the tower body 1 and is used to monitor the free fall and spherical shrinkage state of the droplets after being atomized by the atomizing nozzle 2 in the tower body 1.

[0062] Furthermore, this embodiment provides an application process for the microgravity granulation equipment described above for the synthesis of lithium iron phosphate cathode materials:

[0063] S1: The lithium iron phosphate precursor slurry is conveyed to the atomizing nozzle 2 for atomization treatment to obtain precursor slurry droplets with a particle size of 50μm;

[0064] S2: The precursor slurry droplets fall along the channel inside the tower 1 in the direction of gravity for drying and granulation to obtain secondary particles of lithium iron phosphate precursor; wherein, the falling height is 2m, the temperature of the channel inside the tower 1 is controlled at 200℃ by the thermal radiation heating device 3, and the vacuum degree of the channel inside the tower 1 is controlled at -0.098MPa by the vacuum system 4.

[0065] S3: The secondary particles of the lithium iron phosphate precursor fall into the particle collection bin 5 at the bottom of the tower body 1.

[0066] In practical applications, the secondary particles of lithium iron phosphate precursor produced by the microgravity granulation equipment provided by this invention are nearly spherical with a bulk density of not less than 1.8 g / cm³, which is 12%-15% higher than that of traditional methods. These secondary lithium iron phosphate precursor particles are tightly packed during sintering, increasing the contact area between particles. This results in an increase of over 20% in the intrinsic conductivity of the sintered lithium iron phosphate cathode material, a compaction density of 2.6 g / cm³-2.8 g / cm³, a 0.1C discharge capacity ≥159 mAh / g, a 10C high-rate discharge capacity retention rate ≥95%, and a capacity decay rate ≤5% after 500 cycles.

[0067] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.

Claims

1. A microgravity granulation device for the synthesis of cathode materials, characterized in that, include: The tower body (1) has a channel inside which it falls along the direction of gravity; Atomizing nozzle (2) is disposed at the top of the tower body (1); A thermal radiation heating device (3) is installed on the side wall of the tower body (1); And a vacuum system (4), connected to the tower body (1), for maintaining the vacuum level inside the tower body (1).

2. The microgravity granulation equipment according to claim 1, characterized in that, The effective drop height of the passage is 1.5m-3m.

3. The microgravity granulation equipment according to claim 1, characterized in that, The nozzle orifice diameter of the atomizing nozzle (2) is 10μm-100μm.

4. The microgravity granulation equipment according to claim 1, characterized in that, The thermal radiation heating device (3) is an infrared heater, which is arranged around the side wall of the tower body (1).

5. The microgravity granulation equipment according to claim 4, characterized in that, The infrared heaters are arranged in sections along the height of the tower body (1), and the heating temperature of each section of the infrared heater is independently adjustable.

6. The microgravity granulation equipment according to claim 1, characterized in that, The vacuum system (4) includes a vacuum pump assembly and a vacuum interface connected to the side wall of the tower body (1). The vacuum system (4) can maintain the vacuum level inside the tower body (1) at -0.095MPa to -0.098MPa.

7. The microgravity granulation equipment according to any one of claims 1-6, characterized in that, The bottom of the tower body (1) is provided with a particle collection chamber (5), which is used to receive secondary particles that have fallen freely and been dried.

8. The microgravity granulation equipment according to any one of claims 1-6, characterized in that, The top of the tower body (1) is also equipped with a pressure sensor, which is electrically connected to the controller of the vacuum system (4) for real-time monitoring and adjustment of the vacuum level inside the tower.

9. The microgravity granulation equipment according to any one of claims 1-6, characterized in that, The front end of the atomizing nozzle (2) is also connected to a slurry conveying system (6).

10. The microgravity granulation equipment according to any one of claims 1-6, characterized in that, The side wall of the tower body (1) is also provided with an observation window (7), which is used to monitor the free fall and spherical shrinkage state of the droplets after being atomized by the atomizing nozzle (2) in the tower body (1).

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