A sintering device and sintering method for a cathode material

Abstract

The present invention relates to the field of cathode materials, and discloses a sintering device for cathode materials, which is successively provided with: a first rotary kiln from top to bottom. The first rotary kiln includes a stainless steel kiln body, a heater jacket arranged outside the stainless steel kiln body, a screw arranged inside the stainless steel kiln body, and a kiln inner lining arranged inside the stainless steel kiln body; a second rotary kiln, the inlet of the second rotary kiln is connected to the outlet of the first rotary kiln through a pipeline, and the second rotary kiln is provided with a primary sintering section and a primary cooling section; a mixer, a metering bin and a screw bin are respectively installed at the inlet and outlet at the top of the mixer. The metering bin is connected to the outlet of the second rotary kiln, and a ceramic inner lining is installed in the inner cavity of the mixer; a third rotary kiln, the inlet of the third rotary kiln is connected to the screw bin, and the third rotary kiln is divided into a secondary sintering section and a secondary cooling section. The sintering device for cathode materials of the present invention solves the problems of large floor area, high energy consumption, low production capacity and high cost of the existing sintering process.

Description

Technical Field

[0001] The present invention relates to the field of cathode materials, and particularly to a sintering device and a sintering method for cathode materials. Background Art

[0002] Currently, there are three characteristics in the development of the world's battery industry. First, green and environmentally friendly batteries are developing rapidly, including lithium-ion batteries, nickel-metal hydride batteries, etc. Second, the transformation from primary batteries to secondary batteries is in line with the sustainable development strategy. Third, batteries are further developing towards smaller, lighter, and thinner directions. Among commercial rechargeable batteries, lithium-ion batteries have the highest specific energy. In particular, polymer lithium-ion batteries can achieve the thinness of rechargeable batteries. Because lithium-ion batteries have high volume specific energy and mass specific energy, are rechargeable and pollution-free, and possess the three major characteristics of the current battery industry development, they have a relatively rapid growth in developed countries. The multi-component cathode material is the most important part of lithium-ion batteries. How to produce multi-component cathode materials with excellent performance in an efficient, environmentally friendly, and energy-saving manner is the main theme pursued by current researchers. Conventional cathode materials (such as lithium manganate, lithium cobaltate, lithium iron phosphate, lithium nickel manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium nickel cobalt manganese aluminate, and lithium-rich manganese-based materials, etc.) are all sintered at high temperature through a roller hearth kiln, and after cooling, they are crushed, coated, and subjected to secondary sintering treatment to ensure that the capacity, cycle performance, rate performance, and safety performance of the materials meet the requirements. However, this type of production method will have problems such as a large floor area of equipment, high energy consumption, low production capacity, and high cost.

[0003] Therefore, it is urgent to develop an efficient and energy-saving sintering device and a sintering method for producing cathode materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a sintering device and a sintering method for cathode materials, and this sintering device for cathode materials is used to improve the problems of large floor area, high energy consumption, low production capacity, and high cost in the existing process.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A sintering device for cathode materials is provided with the following components from top to bottom in sequence:

[0007] A first rotary kiln, the first rotary kiln includes a stainless steel kiln body, a heater jacket arranged outside the stainless steel kiln body, a screw arranged inside the stainless steel kiln body, and a kiln body lining is arranged inside the stainless steel kiln body;

[0008] A second rotary kiln, the inlet of the second rotary kiln is connected to the outlet of the first rotary kiln through a pipeline, and the second rotary kiln is provided with a primary sintering section and a primary cooling section;

[0009] A mixer, with a metering bin and a screw bin respectively installed at the inlet and outlet at the top of the mixer. The metering bin is connected to the outlet of the second rotary kiln, and a ceramic lining is installed in the inner cavity of the mixer;

[0010] A third rotary kiln, with its inlet connected to the screw bin. The third rotary kiln is divided into a secondary sintering section and a secondary cooling section.

[0011] Preferably, a feed inlet is provided at the feed end of the first rotary kiln.

[0012] Preferably, a first supplementary air inlet and a first recycled air inlet are provided at the discharge end of the first rotary kiln.

[0013] Preferably, a first jack is provided at a position opposite to the feed inlet of the first rotary kiln in the vertical direction.

[0014] Preferably, the material of the kiln inner lining is selected from one of stainless steel, alumina ceramic, silicon carbide ceramic and silicon nitride ceramic.

[0015] Preferably, a second exhaust port communicating with the first recycled air inlet is provided at the feed end of the second rotary kiln, and a second supplementary air inlet and a second recycled air inlet are provided at the discharge end of the second rotary kiln.

[0016] Preferably, the mixer is further provided with a coating agent feed inlet.

[0017] Preferably, a second jack for discharging is provided at a position opposite to the screw bin of the third rotary kiln in the vertical direction.

[0018] Preferably, a third air inlet is provided at the discharge end of the third rotary kiln, and a third exhaust port communicating with the second recycled air inlet is provided at the feed end of the third rotary kiln.

[0019] Preferably, the third rotary kiln is provided with a discharge port.

[0020] Preferably, the hot materials are transported between the rotary kilns by gravity transportation; the atmosphere introduced into the rotary kiln is continuously recycled, that is, a second exhaust port communicating with the first recycled air inlet is provided at the feed end of the second rotary kiln, and a third exhaust port communicating with the second recycled air inlet is provided at the feed end of the third rotary kiln.

[0021] A method for sintering a cathode material, comprising the following steps:

[0022] (1) Pre-burning and dehydrating the precursor and the lithium source in the first rotary kiln to obtain a mixed material A;

[0023] (2) Sintering the mixed material for the first time in the second rotary kiln, cooling and discharging, and then mixing it with a coating agent to obtain a mixed material B;

[0024] (3) Feed the mixture B into the third rotary kiln for the second sintering, cooling, sieving, and demagnetization to obtain the cathode material.

[0025] Preferably, the temperature of the pre-sintering dehydration in step (1) is 300°C - 500°C, and the time is 1 - 4 h.

[0026] Preferably, the atmosphere in the first, second, and third rotary kilns is one of air, nitrogen, and oxygen.

[0027] More preferably, the atmosphere in the rotary kiln is oxygen.

[0028] Preferably, the temperature of the first sintering in step (2) is 600°C - 900°C, and the time is 4 - 12 h.

[0029] Preferably, the cooling and discharging temperature in step (2) is 25°C - 400°C.

[0030] Preferably, the coating agent in step (2) is one or more of aluminum oxide, titanium oxide, aluminum phosphate, meta-aluminum phosphate, yttrium phosphate, and boric acid.

[0031] Preferably, the temperature of the second sintering in step (3) is 200°C - 600°C, and the time is 3 - 10 h.

[0032] Preferably, the cathode material in step (3) is one or more of lithium manganate, lithium cobaltate, lithium iron phosphate, lithium nickel manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium nickel cobalt manganese aluminate, and lithium-rich manganese-based materials.

[0033] The beneficial technical effects of the present invention are:

[0034] The cathode material sintering device of the present invention solves the problems of large floor area, high energy consumption, low production capacity, and high cost in the existing sintering process.

[0035] 1) The first rotary kiln in the pre-sintering section combines a screw and an inclined-angle discharging, which greatly avoids the problem of difficult discharging caused by factors such as sample caking and wall sticking in the pre-sintering section. Moreover, the pre-sintering section does not require cooling and can be directly input into the first sintering section, playing an energy-saving role;

[0036] 2) Sintering the cathode material in the second rotary kiln for the first time not only can prevent wall sticking, but also because the sintering material is in a dynamic process, the sample after the first sintering can enter the next link without mechanical crushing, saving a crushing process and equipment investment. At the same time, due to the continuous turning of the material during the sintering process, the material is heated evenly and contacts the atmosphere sufficiently, reducing Li / Ni mixing and improving the material consistency, thereby enhancing the electrochemical performance of the material;

[0037] 3) The gas introduced into the third rotary kiln can be recycled and applied to the second rotary kiln after being discharged, and the hot gas discharged from the second rotary kiln can be recycled and utilized in the preheating section, greatly saving gas consumption.

[0038] 4) The discharge temperature of the second rotary kiln can be controlled between 25°C and 400°C by adjusting the length of the heating zone. The second rotary kiln and the third rotary kiln have an integrated heating and cooling structure. The entire process transfers materials by gravity instead of conventional negative pressure transportation, further reducing costs. At the same time, since the cooling process is reduced, the process time is saved, thus greatly improving production efficiency. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of the positive electrode material sintering method of Example 1;

[0040] Figure 2 It is a schematic structural diagram of the first rotary kiln;

[0041] Figure 3 It is a schematic structural diagram of the second rotary kiln and the third rotary kiln;

[0042] Figure 4 It is a schematic production process diagram of Comparative Example 1. Detailed Embodiments

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below through embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the scope of the present invention.

[0044] Example 1

[0045] As Figures 1 to 3 shown: A positive electrode material sintering device is provided successively from top to bottom with:

[0046] The first rotary kiln 100, the first rotary kiln 100, the first rotary kiln 100 includes a stainless - steel kiln body 3, a heater jacket 2 arranged outside the stainless - steel kiln body 3, a screw 7 arranged inside the stainless - steel kiln body 3. There is a kiln inner lining 4 inside the stainless - steel kiln body 3. The feeding end of the first rotary kiln 100 is provided with a feeding port 1, the discharging end of the first rotary kiln 100 is provided with a first supplementary air inlet 5 and a first recycled air inlet 6, and a first jack 14 is provided at the feeding end of the first rotary kiln 100 at a position opposite to the feeding port 1 in the up - down direction; the uniformly - mixed precursor and lithium source are conveyed from the feeding port 1 to the first rotary kiln 100 located on the third - floor position. The pre - sintering temperature at the heater jacket 2 is set to 400 °C through the controller, then the first jack 14 is adjusted to make the stainless - steel kiln body 3 generate an inclination angle, and at the same time, the rotation speed of the screw 7 is set to control the sintering time. Among them, the rotation direction of the kiln inner lining 4 of the first rotary kiln 100 is opposite to the discharging direction of the screw 7, and then the pre - sintered mixture is continuously conveyed downward while it is hot by the action of gravity to the inlet inside the second rotary kiln 200 with a primary sintering section 15 located directly below.

[0047] The second rotary kiln 200, the inlet of the second rotary kiln 200 is connected to the outlet of the first rotary kiln 100 through a pipeline. The second rotary kiln 200 is provided with a primary sintering section 15 and a primary cooling section 8; the mixture is slowly conveyed to the discharging port in the second rotary kiln 200 due to the acting force of the inclined kiln body. Under the conditions of an oxygen atmosphere and a temperature of 650 °C, it first passes through the primary sintering section 15 and then enters the primary cooling section 8, and the discharging temperature is controlled to 200 °C by adjusting the length of the heating zone.

[0048] The mixer 400, the inlet and outlet at the top of the mixer 400 are respectively equipped with a metering bin 11 and a screw bin 12. The metering bin 11 is connected to the outlet of the second rotary kiln 200. A ceramic inner lining 10 is installed in the inner cavity of the mixer 400. The mixer 400 is provided with a coating agent feeding port 9; it is discharged to the second floor by the action of gravity, and the weight of the material fed into the mixer 400 is measured through the metering bin 11, and the coating agent is added from the coating agent feeding port 9. After being uniformly mixed, it is discharged to the screw bin 12 at the first - floor position.

[0049] The third rotary kiln 300, the inlet of the third rotary kiln 300 is connected to the screw bin 12. The third rotary kiln 300 is divided into a secondary sintering section 16 and a secondary cooling section 17; the mixture B is fed into the third rotary kiln 300, and under the conditions of an oxygen atmosphere and a temperature of 350 °C, it is subjected to a second sintering for 3 h, cooled to 30 °C, sieved, and demagnetized to obtain the cathode material.

[0050] The entire sintering process is carried out in an oxygen atmosphere. Oxygen is introduced through the third air inlet 22 at the discharge end of the third rotary kiln 300 and discharged from the third exhaust port 23 at the feed end of the third rotary kiln 300 and recycled as the intake air of the second recovery air inlet 21 at the discharge end of the second rotary kiln 200. The second rotary kiln 200 is provided with a second supplementary air inlet 20 and a second recovery air inlet 21 at the discharge end. Similarly, the exhaust gas of the second rotary kiln 200 is recycled as the intake air of the first rotary kiln 100, greatly saving gas consumption.

[0051] A method for sintering a cathode material, comprising the following steps:

[0052] (1) Add the precursor and lithium source into the first rotary kiln 100, and carry out pre-sintering dehydration for 1 h under an oxygen atmosphere and at a temperature of 400 °C to obtain a mixed material A;

[0053] (2) Add the mixed material into the second rotary kiln 200, and carry out the first sintering for 2 h under an oxygen atmosphere and at a temperature of 650 °C, cool to 200 °C and discharge, and then mix with alumina to obtain a mixed material B;

[0054] (3) Feed the mixed material B into the third rotary kiln 300, and carry out secondary sintering for 3 h under an oxygen atmosphere and at a temperature of 350 °C, cool to 30 °C, screen, and demagnetize to obtain the cathode material.

[0055] Example 2

[0056] As Figures 1 to 3 shown: A sintering device for a cathode material is successively provided with:

[0057] The first rotary kiln 100, the first rotary kiln 100. The first rotary kiln 100 includes a stainless steel kiln body 3, a heater jacket 2 arranged outside the stainless steel kiln body 3, a screw 7 arranged inside the stainless steel kiln body 3. A kiln inner lining 4 is arranged inside the stainless steel kiln body 3. The feed end of the first rotary kiln 100 is provided with a feed inlet 1, the discharge end of the first rotary kiln 100 is provided with a first supplementary air inlet 5 and a first recovery air inlet 6, and the first rotary kiln 100 is provided with a first jack 14 opposite to the feed inlet 1 in the up and down position; The uniformly mixed precursor and lithium source are transported from the feed inlet 1 to the first rotary kiln 100 located on the third floor. Set the pre-sintering temperature at the heater jacket 2 to 400 °C through the controller, then adjust the first jack 14 to make the stainless steel kiln body 3 generate an inclination angle, and at the same time set the rotation speed of the screw 7 to control the sintering time. The rotation direction of the kiln inner lining 4 of the first rotary kiln 100 is opposite to the discharge direction of the screw 7, and then use the gravity to continuously transport the pre-sintered mixed material while it is hot to the inlet inside the second rotary kiln 200 with a primary sintering section 15 arranged directly below.

[0058] The second rotary kiln 200, the inlet of the second rotary kiln 200 is connected to the outlet of the first rotary kiln 100 through a pipeline, and the second rotary kiln 200 is provided with a primary sintering section 15 and a primary cooling section 8; the mixed material is slowly conveyed towards the discharge port in the second rotary kiln 200 due to the tilting force of the kiln body, first passes through the primary sintering section 15 under the conditions of an oxygen atmosphere and a temperature of 700 °C, and then enters the primary cooling section 8, and the discharge temperature is controlled at 400 °C by adjusting the length of the heating zone.

[0059] The mixer 400, the inlet and outlet at the top of the mixer 400 are respectively equipped with a metering bin 11 and a screw bin 12, the metering bin 11 is connected to the outlet of the second rotary kiln 200, a ceramic lining 10 is installed in the inner cavity of the mixer 400, and the mixer 400 is provided with a coating agent feed port 9; the material is discharged to the second floor under the action of gravity, and the weight of the material fed into the mixer 400 is measured by the metering bin 11, and the coating agent is added from the coating agent feed port 9, and after being mixed evenly, it is discharged to the screw bin 12 at the first floor position.

[0060] The third rotary kiln 300, the inlet of the third rotary kiln 300 is connected to the screw bin 12, and the third rotary kiln 300 is divided into a secondary sintering section 16 and a secondary cooling section 17; the mixed material B is fed into the third rotary kiln 300, and under the conditions of an oxygen atmosphere and a temperature of 400 °C, it is subjected to secondary sintering for 3 h, cooled to 30 °C, sieved, and demagnetized to obtain the positive electrode material.

[0061] The entire sintering process is carried out in an oxygen atmosphere. Oxygen is introduced from the third air inlet 22 at the discharge end of the third rotary kiln 300, discharged from the third exhaust port 23 at the feed end of the third rotary kiln 300 and recycled as the intake air of the second recovery air inlet 21 at the discharge end of the second rotary kiln 200. The discharge end of the second rotary kiln 200 is provided with a second supplementary air inlet 20 and a second recovery air inlet 21. Similarly, the exhaust gas of the second rotary kiln 200 is recycled as the intake air of the first rotary kiln 100, greatly saving gas.

[0062] A method for sintering a positive electrode material, comprising the following steps:

[0063] (1) Add the precursor and lithium source into the first rotary kiln 100, and under the conditions of an oxygen atmosphere and a temperature of 400 °C, carry out pre-burning dehydration for 1 h to obtain the mixed material A;

[0064] (2) Add the mixed material into the second rotary kiln 200, and under the conditions of an oxygen atmosphere and a temperature of 700 °C, carry out first sintering for 2 h, cool to 400 °C and discharge, and then mix with alumina to obtain the mixed material B;

[0065] (3) Feed mixture B into the third rotary kiln 300, and conduct the second sintering for 3 h under an oxygen atmosphere at a temperature of 400 °C, cool to 30 °C, screen, and demagnetize to obtain the cathode material.

[0066] Example 3

[0067] As Figures 1 to 3 shown: A cathode material sintering device is successively provided from top to bottom with:

[0068] The first rotary kiln 100, the first rotary kiln 100. The first rotary kiln 100 includes a stainless steel kiln body 3, a heater jacket 2 arranged outside the stainless steel kiln body 3, and a screw 7 arranged inside the stainless steel kiln body 3. A kiln inner lining 4 is arranged inside the stainless steel kiln body 3. The feeding end of the first rotary kiln 100 is provided with a feeding port 1, the discharging end of the first rotary kiln 100 is provided with a first supplementary air inlet 5 and a first recovery air inlet 6, and the first rotary kiln 100 is provided with a first jack 14 that is opposite to the feeding port 1 in the up and down position; Feed the uniformly mixed precursor and lithium source from the feeding port 1 to the first rotary kiln 100 located on the third floor. Set the pre-sintering temperature at the heater jacket 2 to 450 °C through the controller, then adjust the first jack 14 to make the stainless steel kiln body 3 generate an inclination angle, and at the same time set the rotation speed of the screw 7 to control the sintering time. Among them, the rotation direction of the kiln inner lining 4 of the first rotary kiln 100 is opposite to the discharging direction of the screw 7, and then use the gravity to continuously convey the pre-sintered mixture while it is hot to the inlet of the second rotary kiln 200 provided with a primary sintering section 15 directly below.

[0069] The second rotary kiln 200. The inlet of the second rotary kiln 200 is connected to the outlet of the first rotary kiln 100 through a pipeline. The second rotary kiln 200 is provided with a first sintering section 15 and a first cooling section 8; The mixture is

[0070] slowly conveyed to the discharging port in the second rotary kiln 200 due to the inclination force of the kiln body, and under an oxygen atmosphere at a temperature of 700 °C, first pass through the first sintering section 15, and then enter the first cooling section 8, and control the discharging temperature to 25 °C by adjusting the length of the heating zone.

[0071] The mixer 400. The inlet and outlet at the top of the mixer 400 are respectively equipped with a metering bin 11 and a screw bin 12. The metering bin 11 is connected to the outlet of the second rotary kiln 200. A ceramic inner lining 10 is installed in the inner cavity of the mixer 400. The mixer 400 is provided with a coating agent feeding port 9; Discharge to the second floor under the action of gravity, measure the weight of the mixture fed into the mixer 400 through the metering bin 11, add the coating agent from the coating agent feeding port 9, and discharge the uniformly mixed material to the screw bin 12 located on the first floor.

[0072] The third rotary kiln 300, the inlet of the third rotary kiln 300 is connected to the screw bin 12, and the third rotary kiln 300 is divided into a second sintering section 16 and a second cooling section 17; the mixed material B is introduced into the third rotary kiln 300, and under the condition of an oxygen atmosphere and a temperature of 350 °C, the second sintering is carried out for 3 h, cooled to 30 °C, sieved, and demagnetized to obtain the cathode material.

[0073] The entire sintering process is carried out in an oxygen atmosphere. Oxygen is introduced through the third air inlet 22 at the discharge end of the third rotary kiln 300, discharged from the third exhaust port 23 at the feed end of the third rotary kiln 300 and recycled as the intake air of the second recovery air inlet 21 at the discharge end of the second rotary kiln 200. The second rotary kiln 200 is provided with a second supplementary air inlet 20 and a second recovery air inlet 21 at the discharge end. Similarly, the exhaust gas of the second rotary kiln 200 is recycled as the intake air of the first rotary kiln 100, greatly saving gas consumption.

[0074] A method for sintering a cathode material, comprising the following steps:

[0075] (1) Add the precursor and lithium source into the first rotary kiln 100, and carry out pre-burning dehydration for 1 h under the condition of a nitrogen atmosphere and a temperature of 450 °C to obtain the mixed material A;

[0076] (2) Add the mixed material into the second rotary kiln 200, and carry out the first sintering for 2 h under the condition of a nitrogen atmosphere and a temperature of 700 °C, cool to 25 °C and discharge, then mix with alumina to obtain the mixed material B;

[0077] (3) Introduce the mixed material B into the third rotary kiln 300, and carry out the second sintering for 3 h under the condition of a nitrogen atmosphere and a temperature of 350 °C, cool to 30 °C, sieve, and demagnetize to obtain the cathode material.

[0078] Comparative Example 1

[0079] A high-temperature sintering roller hearth kiln, one is used as the first sintering kiln, and the other is used as the second sintering kiln. The production process is as Figure 4 shown; each sagger of the first sintering kiln is loaded with 4 Kg of materials, 6 saggers are loaded in each row, the saggers are conveyed by roller rods, and the same temperature and time are set according to the length of the kiln and the running speed of the roller rods, and the same degree of oxygen atmosphere is provided. After discharging, the materials have been cooled to room temperature and are conveyed into a mechanical mill for crushing, then metered and mixed evenly with the coating agent in a pear knife mixer, and then conveyed into the sagger and sent to the second sintering kiln for second sintering. After sieving, demagnetizing, and packing, the product cathode material is obtained.

[0080] By comparing the required furnace length, electric power, air ventilation volume and equipment investment of the above-mentioned Example 1 and Comparative Example 1 through fixed production capacity, the differences are as shown in Table 1 below:

[0081] Table 1

[0082]

[0083] By comparing the parameters in the above table, it can be found that under the same production capacity, compared with the roller hearth kiln sintering in Comparative Example 1, the initial equipment investment of the rotary kiln in Example 1 is very close, but the total length of the furnace body is reduced by about 9 times, the energy consumption is reduced by about 2 times, and the ventilation volume is reduced by 7.4 times. Therefore, the production efficiency and operating cost of the rotary kiln process will be much lower than the existing roller hearth kiln process, and it will have a great impact on the existing process.

Claims

1. A sintering device for a cathode material, characterized in that, From top to bottom, there are provided successively: A first rotary kiln (100), the first rotary kiln (100) including a stainless - steel kiln body (3), a heater jacket (2) arranged outside the stainless - steel kiln body (3), a screw (7) arranged inside the stainless - steel kiln body (3), and a kiln inner lining (4) arranged inside the stainless - steel kiln body (3); A second rotary kiln (200), the inlet of the second rotary kiln (200) being connected to the outlet of the first rotary kiln (100) through a pipeline, and the second rotary kiln (200) being provided with a primary sintering section (15) and a primary cooling section (8); A mixer (400), a metering bin (11) and a screw bin (12) being respectively installed at the inlet and outlet at the top of the mixer (400), the metering bin (11) being connected to the outlet of the second rotary kiln (200), and a ceramic inner lining (10) being installed inside the cavity of the mixer (400); A third rotary kiln (300), the inlet of the third rotary kiln (300) being connected to the screw bin (12), and the third rotary kiln (300) being divided into a secondary sintering section (16) and a secondary cooling section (17).

2. The sintering device for the positive electrode material according to claim 1, wherein One end of the first rotary kiln (100) is provided with a feed inlet (1); the discharge end of the first rotary kiln (100) is provided with a first supplementary air inlet (5) and a first recovery air inlet (6); the first rotary kiln (100) is provided with a jack one (14) which is opposite to the feed inlet (1) in the up - down position.

3. The sintering device for the cathode material according to claim 1, characterized in that The feed end of the second rotary kiln (200) is provided with a second exhaust port (19) which communicates with the first recovery air inlet (6), and the discharge end of the second rotary kiln (200) is provided with a second supplementary air inlet (20) and a second recovery air inlet (21).

4. The sintering device for the positive electrode material according to claim 1, wherein The mixer (400) is further provided with a coating agent feed inlet (9).

5. The sintering device for the positive electrode material according to claim 1, characterized in that, The third rotary kiln (300) is provided with a jack two (18) for discharging which is opposite to the screw bin (12) in the up - down position.

6. The sintering device for the cathode material according to claim 1, wherein The discharge end of the third rotary kiln (300) is provided with a third air inlet (22), and the feed end of the third rotary kiln (300) is provided with a third exhaust port (23) which is connected to the second recovery air inlet (21).

7. A sintering method for a cathode material, characterized in that, Using the positive electrode material sintering device according to any one of claims 1 to 6, specifically including the following steps: (1) Pre - sintering and dehydrating the precursor and the lithium source in the first rotary kiln (100) to obtain a mixture A; (2) Passing the mixture A into the second rotary kiln (200), carrying out the first sintering, cooling and discharging, and then mixing with the coating agent to obtain a mixture B; (3) Passing the mixture B into the third rotary kiln (300), carrying out the second sintering, cooling, sieving and demagnetizing to obtain the positive electrode material.

8. The sintering method of the positive electrode material according to claim 7, characterized in that, The atmosphere of the first, second and third rotary kilns is one of air, nitrogen and oxygen.

9. The sintering method of the cathode material according to claim 7, characterized in that, The coating agent in step (2) is one or several of alumina, aluminum hydroxide, titanium oxide, aluminum phosphate, metaphosphoric acid aluminum, yttrium phosphate and boric acid.

10. The sintering method of the positive electrode material according to claim 7, characterized in that, The positive electrode material in step (3) is one or several of lithium manganate, lithium cobaltate, lithium iron phosphate, lithium nickel manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium nickel cobalt manganese aluminate and lithium - rich manganese - based.

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