High-temperature coating machine for improving cycle performance of sodium ion battery positive electrode material

Abstract

The utility model provides a high-temperature coating machine for improving the cycle performance of a sodium-ion battery positive electrode material, relates to the technical field of new energy materials, and solves the technical problem that the existing nano coating agent is not tightly combined with the sodium-ion battery positive electrode material. The tank body is used for coating, the forward rotating blade is used for stirring a coating agent and a coating material, the reverse rotating blade is used for reversely rotating to form a shearing effect so as to enhance the combination degree of the coating agent and the coating material, and the forward rotating blade and the reverse rotating blade are in transmission connection through a transmission mechanism. According to the utility model, materials are uniformly mixed by the forward rotating blades, and a nano coating agent can be tightly coated on the surfaces of sodium ion battery positive electrode material particles under the shearing action by the reverse rotating blades; the coating procedure and the heat treatment are changed into integrated equipment, so that the investment amount is reduced, the production efficiency is improved, and the production energy consumption is reduced; the moisture and residual alkali of the positive electrode material can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy materials, and in particular to a high-temperature coating machine for improving the cycle performance of positive electrode materials of sodium ion batteries. Background Art

[0002] Sodium-ion batteries have the following characteristics: ① abundant reserves and low cost; ② fast charging and high rate; ③ zero-voltage transportation and storage; ④ high safety; ⑥ unique low-temperature performance.

[0003] At present, sodium-ion batteries have good application prospects in two-wheeled vehicles, passenger cars and energy storage fields, but the long cycle, high-temperature gas production and high-temperature storage of sodium-ion batteries have not been effectively solved, thus limiting their widespread application. The cycle, gas production and storage of sodium-ion batteries are usually caused by the instability of the interface between the positive electrode material and the electrolyte, resulting in side reactions. Therefore, solving the stability of the positive electrode material interface is a key technical problem.

[0004] When the existing positive electrode materials are powder coated, due to the different sizes of powder particles between different raw materials, the coating is often uneven, which has an adverse effect on the quality of the finished product. Therefore, as proposed in the patent with publication number CN210045096U, a high-efficiency heating mixer for coating agent production improves the mixing efficiency of the thick mixed liquid by forming an up and down circulation flow of the mixed liquid, and the use effect is better, which solves the problem of too slow mixing efficiency of the thick mixed liquid in the mixer. However, for the nano-encapsulation of the positive electrode material of the sodium ion battery, there is still the problem that the nano-coating agent is not tightly combined with the positive electrode material. Utility Model Content

[0005] The utility model aims to provide a high-temperature coating machine for improving the cycle performance of anode materials of sodium ion batteries, so as to solve the technical problem that the existing nano coating agent is not tightly combined with the cathode materials of sodium ion batteries.

[0006] The embodiments of the present invention are implemented by the following technical solutions:

[0007] A high-temperature coating machine for improving the cycle performance of positive electrode materials of sodium ion batteries comprises a coating tank and a forward-rotating blade for stirring a coating agent and a coating material, and also comprises a reverse-rotating blade for reversely rotating to form a shearing effect to strengthen the bonding degree between the coating agent and the coating material, wherein the forward-rotating blade and the reverse-rotating blade are connected by a transmission mechanism.

[0008] Preferably, the transmission mechanism includes a first rotating shaft and a second rotating shaft that are respectively connected to the forward rotating blade and the reverse rotating blade by shafts. The first rotating shaft and the second rotating shaft are respectively connected to a first rotating disk and a second rotating disk by shafts, and the first rotating disk and the second rotating disk are connected by a plurality of sets of meshing bevel gears.

[0009] Preferably, the transmission mechanism further includes a transmission box body for protecting and rotatably connecting the bevel gears.

[0010] Preferably, the first rotating shaft is connected to a transmission shaft, and the transmission shaft is connected to a driving device for providing driving power.

[0011] Preferably, the tank body further includes a plurality of exhaust pipes provided at the top for discharging gas, a plurality of nozzles for atomizing and spraying the coating agent, and a plurality of intake pipes provided at the bottom for introducing protective gas and cooling gas.

[0012] Preferably, the tank body further includes a feed inlet at the top for feeding and a discharge outlet at the bottom for discharging.

[0013] Preferably, the tank body further includes a heating device for heating it, a heat preservation layer for heat preservation, and a tank shell for providing strength support.

[0014] Preferably, the forward rotating blade is provided with three sheep's horn shapes, and the reverse rotating blade is provided with a scraper shape.

[0015] Adopting this technical solution, with a forward rotating blade and a reverse rotating blade, the forward rotating blade makes the material mix evenly, and the reverse rotating blade enables the nano - coating agent to be tightly coated on the surface of the sodium - ion battery cathode material particles through shear action;

[0016] Integrate the coating process and heat treatment into one device, eliminate the backend heat treatment kiln equipment, reduce investment, improve production efficiency and reduce production energy consumption;

[0017] The coated cathode material can be heated up inside the coater, and at the same time, the two blades can stir simultaneously. Therefore, the coated cathode material is more uniform and dense, and the agglomeration of the cathode material is reduced, improving the tap density of the cathode material;

[0018] When the high - temperature coater is working, the gas concentration inside is higher than that of the conventional track kiln. On the other hand, the temperature of the cathode material can be quickly reduced by external inert gas. Therefore, the moisture and residual alkali of the cathode material can be effectively reduced.

[0019] The technical solution of the embodiment of the present utility model has at least the following advantages and beneficial effects:

[0020] 1. The forward - rotating blades of the present utility model can evenly mix the materials, and the reverse - rotating blades enable the nano - coating agent to be tightly coated on the surface of the sodium - ion battery cathode material particles through shearing action;

[0021] 2. The present utility model integrates the coating process and heat treatment into one device, reducing the investment, improving the production efficiency and reducing the production energy consumption;

[0022] 3. The coated cathode material of the present utility model is more uniform and dense, and the agglomeration of the cathode material is reduced, improving the tap density of the cathode material;

[0023] 4. The present utility model can effectively reduce the moisture and residual alkali of the cathode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present utility model, so they should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0025] Figure 1 FIG. 1 is a schematic cross - sectional structure diagram of the high - temperature coating machine provided in Embodiment 1 of the present utility model;

[0026] Figure 2 FIG. 2 is a schematic top - view structure diagram of the high - temperature coating machine provided in Embodiment 1 of the present utility model;

[0027] Figure 3 FIG. 3 is a schematic structure diagram of the transmission mechanism of the high - temperature coating machine provided in Embodiment 1 of the present utility model;

[0028] Reference numerals: 1, driving device; 2, tank body; 3, exhaust pipe; 4, heating device; 5, transmission mechanism; 51, first rotating shaft; 52, second rotating shaft; 53, first rotating disk; 54, second rotating disk; 55, bevel gear; 56, transmission box body; 6, forward - rotating blade; 7, reverse - rotating blade; 8, heat - insulating layer; 9, intake pipe; 10, discharge port; 11, tank shell; 12, feed port; 13, nozzle; 14, transmission shaft. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. Usually, the components of the embodiments of the present utility model described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0032] In the description of the present invention, it should be noted that if the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or is the orientation or position relationship in which the product of the application is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0033] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Example 1

[0035] A high-temperature coating machine for improving the cycle performance of positive electrode materials for sodium ion batteries comprises a coating tank 2 and a forward-rotating blade 6 for stirring a coating agent and a coating material, and also comprises a reverse-rotating blade 7 for reversely rotating to form a shearing effect to strengthen the bonding degree between the coating agent and the coating material, wherein the forward-rotating blade 6 and the reverse-rotating blade 7 are connected by a transmission mechanism 5.

[0036] In this embodiment, the transmission mechanism 5 includes a first rotating shaft 51 and a second rotating shaft 52 respectively connected to the forward rotating blades 6 and the reverse rotating blades 7. The first rotating shaft 51 and the second rotating shaft 52 are respectively connected to a first rotating disk 53 and a second rotating disk 54. The first rotating disk 53 and the second rotating disk 54 are connected through a plurality of groups of meshing bevel gears 55.

[0037] In this embodiment, the transmission mechanism 5 further includes a transmission box body 56 for protecting and rotatably connecting the bevel gear 55.

[0038] In this embodiment, the first rotating shaft 51 is shaft-connected to a transmission shaft 14, and the transmission shaft 14 is drivingly connected to a driving device 1 for providing driving power.

[0039] In this embodiment, the tank body 2 further includes a plurality of exhaust pipes 3 provided at the top for discharging gas, a plurality of nozzles 13 for atomizing and spraying the coating agent, and a plurality of inlet pipes 9 provided at the bottom for introducing protective gas and cooling gas.

[0040] In this embodiment, the tank body 2 further includes a feed inlet 12 at the top for feeding and a discharge outlet 10 at the bottom for discharging.

[0041] In this embodiment, the tank body 2 further includes a heating device 4 for heating it, a heat preservation layer 8 for heat preservation, and a tank shell 11 for providing strength support.

[0042] In this embodiment, the driving device 1 uses a reduction motor, and the size of the exhaust pipe 3 is adjustable. The exhaust pipe 3 maintains the internal pressure balance and the overflow of moisture during high-temperature coating, and keeps the internal material rapidly cooled when the coating machine cools down.

[0043] In this embodiment, two symmetrically distributed nozzles 13 are located on a circumference with a diameter of 1 / 3 - 2 / 3 of the tank body diameter. The nozzles can form atomized small droplets of 1 - 100 microns from the nano-coating agent solution through high-pressure gas nozzles, so that it can be evenly coated on the surface of the particles of the sodium-ion battery positive electrode material.

[0044] In this embodiment, the material of the coating machine is high-temperature stainless steel, and the inner wall is coated with a tungsten carbide coating. The volume of the tank body is 2m 3 , and the motor speed is 500 rpm.

[0045] In this embodiment, the forward rotating paddle 6 on the upper layer is three-piece sheep horn-shaped with a diameter of 2 / 3 of the tank body diameter, and the reverse rotating paddle 7 on the lower layer is scraper-shaped with a linear distance of 5 cm from the inner wall of the tank body. All paddles have a tungsten carbide coating.

[0046] In this embodiment, the heating device 4 is resistance wire heating with a maximum temperature of 800 °C.

[0047] Working principle and usage method:

[0048] During operation, the forward rotating paddle 6 and the reverse rotating paddle 7 are used. The forward rotating paddle 6 mixes the materials evenly, and the reverse rotating paddle 7 enables the nano-coating agent to be tightly coated on the surface of the sodium-ion battery positive electrode material particles through shear action;

[0049] Integrate the coating process and heat treatment into one device, eliminating the need for a backend heat treatment furnace, reducing investment, improving production efficiency, and lowering production energy consumption;

[0050] After coating, the cathode material can be heated inside the coater. At the same time, two types of paddles can stir simultaneously. Therefore, the coated cathode material is more uniform and dense, reducing the agglomeration of the cathode material and improving the tap density of the cathode material;

[0051] When the high-temperature coater is operating, the gas concentration introduced inside is higher than that of a conventional tunnel furnace. On the other hand, the temperature of the cathode material can be rapidly reduced by external inert gas. Therefore, it can effectively reduce the moisture and residual alkali of the cathode material.

[0052] The sodium-ion layered oxide cathode material product obtained by the above device of the present utility model is subjected to performance testing.

[0053] 1. Free sodium or residual alkali test

[0054] For the free sodium or residual alkali test, an automatic potentiometric titrator, model: METTLER TOLEDO G20, is used. Weigh 5 g of the sample and dissolve it in 40 mL of aqueous solution, sonicate for 30 min, filter, make up the volume to 100 mL in a volumetric flask, shake well and let it stand, then take the supernatant for testing. The results are shown in Table 1.

[0055] 2. Discharge capacity and cycling performance

[0056] The following method is used to test the discharge capacity and cycling performance: After mixing the sodium-ion battery cathode material, conductive carbon black, and binder PVDF in a mass ratio of 80:10:10, add NMP to make a uniform slurry, coat it on aluminum foil, dry, roll it, and then cut it into a cathode sheet with a diameter of 14 mm. Assemble it into a sodium-ion battery using a CR2032-type button battery, with a glass fiber separator and an electrolyte of 1 mol / L NaPF6 solution with a solvent of EC / PC / DEC, and a sodium sheet as the negative electrode. The results are shown in Table 1 and Figure 1-2 as shown (using the materials obtained in Example 1 and Comparative Example 1 as samples for determination).

[0057] 3. Sodium-ion battery test

[0058] Sodium-ion battery test conditions: The temperature is 25°C ± 1°C, the charge-discharge cycle voltage range is 2.0 V - 4.0 V, the current is 0.1C (150 mAh / g), and the cycle test is carried out with a charge of 0.5C and a discharge of 1C. The results are shown in Table 1.

[0059] Table 1. Test results

[0060]

[0061]

[0062] Table 1 gives the comparison data of the physical and chemical properties of the layered oxide cathode material of the sodium-ion battery after coating by the high-temperature coater and the traditional coater in the present invention. Since the high-temperature coater can evenly coat the coating agent on the surface of the cathode material particles, the coating agent can react with the residual alkali on the surface of the cathode material, resulting in the free sodium content and pH value being lower than those of the traditional coater. At the same time, the discharge capacity (148 mAh / g) and the 50-week capacity retention rate (96.49%) are also higher than the capacity (146 mAh / g) and the retention rate (92.15%) of the traditional coater. On the other hand, the high-temperature coater of the present invention continuously stirs during the heating process, so the phenomenon of particle agglomeration will not occur, resulting in the tap density (1.92 g / cm3) being higher than the tap density of 1.92 g / cm3 of the traditional coater. From the above results, it can be seen that the layered oxide cathode material of the sodium-ion battery after coating by the high-temperature coater in the present invention is superior to the existing coater in terms of discharge capacity, rate performance, cycle performance, free sodium, pH, and tap density.

[0063] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, various modifications and changes can be made to the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A high-temperature coating machine for improving the cycling performance of the cathode material of a sodium-ion battery, comprising a tank body (2) for coating and a forward rotating paddle (6) for stirring the coating agent and the coating material, characterized in that: It also includes a counter-rotating blade (7) for counter-rotating to form a shearing effect to strengthen the bonding between the coating agent and the coating material. The forward-rotating blade (6) and the counter-rotating blade (7) are connected by a transmission mechanism (5).

2. The high-temperature coating machine for improving the cycling performance of the cathode material of a sodium-ion battery according to claim 1, characterized in that: The transmission mechanism (5) comprises a first rotating shaft (51) and a second rotating shaft (52) respectively connected to the forward rotating blade (6) and the reverse rotating blade (7); the first rotating shaft (51) and the second rotating shaft (52) are respectively connected to a first rotating disk (53) and a second rotating disk (54); the first rotating disk (53) and the second rotating disk (54) are connected in transmission via a plurality of groups of meshing bevel gears (55).

3. A high-temperature coating machine for improving the cycle performance of the cathode material of a sodium-ion battery according to claim 2, characterized in that: The transmission mechanism (5) also includes a transmission housing (56) for protecting and rotatably connecting the bevel gear (55).

4. A high-temperature coating machine for improving the cycling performance of the cathode material of a sodium-ion battery according to claim 2 or 3, characterized in that: The first rotating shaft (51) is axially connected to a transmission shaft (14), and the transmission shaft (14) is drivingly connected to a driving device (1) for providing driving power.

5. A high-temperature coating machine for improving the cycling performance of the cathode material of a sodium-ion battery according to any one of claims 1-3, characterized in that: The tank body (2) further comprises a plurality of exhaust pipes (3) arranged at the top for exhausting gas, a plurality of nozzles (13) for atomizing and spraying the coating agent, and a plurality of air inlet pipes (9) arranged at the bottom for introducing protective gas and cooling gas.

6. A high-temperature coating machine for improving the cycle performance of the cathode material of a sodium-ion battery according to any one of claims 1-3, characterized in that: The tank body (2) further comprises a feed inlet (12) at the top for feeding materials and a discharge outlet (10) at the bottom for discharging materials.

7. A high-temperature coating machine for improving the cycling performance of the cathode material of a sodium-ion battery according to any one of claims 1-3, characterized in that: The tank body (2) also includes a heating device (4) for heating the tank body, a heat-insulating layer (8) for keeping the tank body warm, and a tank shell (11) for providing strength support thereto.

8. A high-temperature coating machine for improving the cycling performance of the cathode material of a sodium-ion battery according to any one of claims 1-3, characterized in that: The forward-rotating blades (6) are configured as three-piece ram-horn-shaped blades, and the reverse-rotating blades (7) are configured as scraper-shaped blades.

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