Crushing method based on modified cathode material, modified cathode material and preparation method thereof

Abstract

The present application provides a crushing method based on a modified cathode material, the modified cathode material and a preparation method thereof. The above-mentioned crushing method based on the modified cathode material includes the following steps: obtaining a calcined product of talcum powder and a cathode material; putting the talcum powder and the calcined product into a jaw crusher for a first crushing operation to obtain a first crushed material; putting the first crushed material into a roll crusher for a second crushing operation to obtain a second crushed material; transporting the second crushed material to a pulverizer for a pulverizing operation. The above-mentioned crushing method based on the modified cathode material can reduce the wear of the material on the pipe wall during transportation and can reduce the content of metal impurities in the material.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of cathode materials, and particularly to a crushing method for modified cathode materials, a modified cathode material and a preparation method thereof. Background Art

[0002] With the increasing prominence of energy crisis and environmental problems, lithium-ion batteries have attracted much attention due to their many performance advantages such as high safety and no pollution. The cathode material of lithium-ion batteries is an important part of secondary lithium-ion batteries. It not only participates in the electrochemical reaction as an electrode material but also needs to serve as a lithium-ion source. Therefore, how to improve the performance of cathode materials has always been a research hotspot in the field of lithium-ion batteries.

[0003] Most of the methods to improve the performance of cathode materials are to modify the cathode materials. One of the common cathode material modification strategies is to coat the cathode materials. Further, for the coating modification of cathode materials, it is usually carried out in the liquid phase, but it is easy to cause the agglomeration of cathode materials in the liquid phase, which affects the electrochemical performance of cathode materials. Further, in order to reduce the reduction of the performance of cathode materials modified in the liquid phase, solid-phase coating modification has been developed, or doping modification of cathode materials is carried out, which usually includes doping in the solid phase and doping in the liquid phase. Whether it is coating modification or doping modification, in the specific process, it is necessary to pneumatically convey the reaction powder materials, including pneumatically conveying the cathode materials to be modified. Especially when it comes to solid-phase reactions, it is necessary to add cathode materials and various solid powder materials and other materials into the reactor.

[0004] However, during the material transportation process, due to the collision of material particles against the inside of the transportation pipeline, the inner wall of the pipeline will be worn, shortening the service life of the pipeline. At the same time, the transportation pipeline is usually made of metal. When the inner wall is worn, metal impurities will be mixed into the transported materials. Especially the presence of elemental iron will cause battery short circuit or even battery failure. Especially when the transportation pipeline is long, if the inner wall is severely worn, a large amount of metal impurities will be doped into the materials. In addition, after the materials are added into the reactor, it is also necessary to pre-stir the materials to make the materials relatively evenly mixed before carrying out the modification of the cathode materials. Summary of the Invention

[0005] The purpose of the present invention is to at least overcome any deficiencies in the prior art, and provide a crushing method for modified cathode materials, a modified cathode material and a preparation method thereof, which can reduce the wear of materials on the pipe wall during transportation and reduce the content of metal impurities in the materials.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A crushing method for modified cathode materials includes the following steps:

[0008] Obtain the calcined product of talcum powder and the cathode material;

[0009] Put the talcum powder and the calcined product into a jaw crusher for the first crushing operation to obtain the first crushed material;

[0010] Put the first crushed material into a roll crusher for the second crushing operation to obtain the second crushed material;

[0011] Transport the second crushed material to a grinder for grinding operation.

[0012] In one embodiment, obtain 8 to 15 parts by mass of the talcum powder and 85 to 92 parts by mass of the calcined product.

[0013] In one embodiment, the talcum powder includes SiO2, MgO, Al2O3 and impurities.

[0014] In one embodiment, the talcum powder includes the following components in parts by mass:

[0015] SiO2 50 - 70 parts;

[0016] MgO 8 - 35 parts;

[0017] Al2O3 0 - 1 part;

[0018] Impurities 4 - 10 parts.

[0019] In one embodiment, the particle size D50 of the talcum powder is 3μm - 20μm.

[0020] In one embodiment, the particle size D90 of the talcum powder is 6μm - 15μm.

[0021] In one embodiment, the particle size of the calcined product is 30mm - 100mm.

[0022] In one embodiment, the particle size of the first crushed material is 2mm - 10mm.

[0023] In one embodiment, the particle size of the second crushed material is 1μm - 50μm.

[0024] In one embodiment, the cathode material is cathode material NCM811.

[0025] In one embodiment, transport the second crushed material to a grinder for grinding operation through a pipeline of 3m - 5m.

[0026] A preparation method of a modified cathode material, comprising the crushing method of the modified cathode material described in any one of the above embodiments.

[0027] A modified cathode material is prepared by using the preparation method of the modified cathode material described in any one of the above embodiments.

[0028] Compared with the prior art, the present invention has at least the following advantages:

[0029] 1. In the crushing method of the modified cathode material of the present invention, talcum powder is added when crushing the calcined product of the cathode material. Since the particle size of the calcined product of the cathode material in the jaw crusher and the roll crusher is relatively large, and talcum powder can adhere well to the jaw crusher and the roll crusher, thus talcum powder can preferably reduce the friction between the calcined product and the inner walls of the jaw crusher and the roll crusher respectively, that is, reduce the wear of the cathode material on the inner walls of the jaw crusher and the roll crusher respectively, and preferably ensure the service life of the inner walls of the jaw crusher and the roll crusher, and preferably reduce the content of metal substances in the modified cathode material; In addition, it can preferably ensure the reduction of the particle size of the calcined product after the calcined product passes through the jaw crusher and the roll crusher, so that the jaw crusher and the roll crusher are used in combination with the pulverizer, that is, preferably ensure quickly reaching the required pulverized particle size of the calcined product, and because the calcined product mixed with talcum powder has good fluidity, thus reducing the friction and collision between the calcined product and the inner wall of the pulverizer, and further preferably reducing the content of metal substances in the modified cathode material;

[0030] 2. In the crushing method of the modified cathode material of the present invention, since talcum powder can play a role in modified coating or doping in the modification of the cathode material, that is, talcum powder will not become an impurity of the cathode material after being added to the calcined product of the cathode material for auxiliary crushing and pulverization, and talcum powder as a modifying substance realizes full mixing with the cathode material during the crushing and pulverization of the cathode material. Therefore, adding talcum powder when crushing the calcined product of the cathode material eliminates the pre-stirring and mixing process of the modifying substance and the cathode material in the preparation process of the modified cathode material, effectively improves the preparation efficiency of the modified cathode material, and realizes the improvement of the performance of the cathode material. Description of the Drawings

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0032] Figure 1The figure is a flowchart of a crushing method based on a modified cathode material in an embodiment of the present invention. Detailed implementation manners

[0033] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0034] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a middle element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0036] This application also provides a crushing method based on a modified cathode material. To better understand the crushing method based on a modified cathode material of this application, the following further explains the crushing method based on a modified cathode material of this application:

[0037] One embodiment of the crushing method based on a modified cathode material includes some or all of the following steps:

[0038] S100. Obtain the calcined product of talcum powder and cathode material. It can be understood that since talcum powder can play a role in modifying coating or doping in the modification of cathode materials, obtaining the calcined product of talcum powder and cathode material for mixing, crushing and pulverizing effectively realizes the pre-stirring and mixing of the modifying substance and the cathode material, and further realizes the subtraction of the pre-stirring and mixing process of the modifying substance and the cathode material in the preparation process of the modified cathode material, effectively accelerating the preparation efficiency of the modified cathode material and realizing the improvement of the performance of the cathode material.

[0039] S200. Put the talcum powder and the calcined material into a jaw crusher for the first crushing operation to obtain the first crushed material. It can be understood that since the talcum powder has good fluidity and good adhesiveness, when the talcum powder and the calcined material are put into the jaw crusher for the first crushing operation, the talcum powder and the calcined material are crushed together in the jaw crusher, so that the talcum powder quickly adheres to the inner wall of the jaw crusher, reducing the direct collision and friction between the calcined material and the inner wall of the jaw crusher during the crushing process, reducing the wear of the positive electrode material on the inner wall of the jaw crusher respectively, thus better ensuring the service life of the inner wall of the jaw crusher and better reducing the content of metal substances in the modified positive electrode material.

[0040] S300. Put the first crushed material into a roll crusher for the second crushing operation to obtain the second crushed material. It can be understood that in order to better ensure the effective crushing of the calcined material and reduce the loss of the calcined material during the crushing process, after the calcined material with larger particles is crushed in the jaw crusher, it is then put into the roll crusher for more delicate crushing, effectively and quickly reducing the particle size D90 of the calcined material; in addition, when the first crushed material enters the roll crusher, the talcum powder will quickly adhere to the inner wall of the roll crusher, reducing the direct collision and friction between the calcined material and the inner wall of the roll crusher during the crushing process, reducing the wear of the positive electrode material on the inner wall of the roll crusher respectively, thus better ensuring the service life of the roll crusher and better reducing the content of metal substances in the modified positive electrode material.

[0041] S400. Transport the second crushed material to a pulverizer for pulverization operation. It can be understood that after the calcined material passes through the jaw crusher and the roll crusher, the reduction of the particle size of the calcined material can be better ensured. Then, the jaw crusher and the roll crusher are used in combination with the pulverizer, which better ensures quickly reaching the required pulverized particle size of the calcined material. And because the calcined material mixed with talcum powder has good fluidity, the friction and collision between the calcined material and the inner wall of the pulverizer are reduced, further better reducing the content of metal substances in the modified positive electrode material; in addition, since the talcum powder can play a role in modification coating or doping in the modification of the positive electrode material, that is, the talcum powder will not become an impurity of the positive electrode material after being added to the calcined material of the positive electrode material for auxiliary crushing and pulverization, and the talcum powder, as a modifying substance, is fully mixed with the positive electrode material during the crushing and pulverization of the positive electrode material. Therefore, when adding talcum powder to crush the calcined material of the positive electrode material, the pre-stirring and mixing process of the modifying substance and the positive electrode material in the preparation process of the modified positive electrode material is eliminated, effectively accelerating the preparation efficiency of the modified positive electrode material and improving the performance of the positive electrode material.

[0042] The above-mentioned crushing method based on the modified cathode material adds talcum powder when crushing the calcined product of the cathode material. Since the particle size of the calcined product of the cathode material in the jaw crusher and the roll crusher is relatively large, talcum powder can adhere well to the jaw crusher and the roll crusher, thereby reducing the friction between the calcined product and the inner walls of the jaw crusher and the roll crusher, that is, reducing the wear of the cathode material on the inner walls of the jaw crusher and the roll crusher, thus better ensuring the service life of the inner walls of the jaw crusher and the roll crusher, and better reducing the content of metal substances in the modified cathode material; in addition, after the calcined product passes through the jaw crusher and the roll crusher, it can better ensure the reduction of the particle size of the calcined product, so that the jaw crusher and the roll crusher are used in combination with the pulverizer, that is, better ensuring that the required crushing particle size of the calcined product is quickly achieved, and because the calcined product mixed with talcum powder has good fluidity, the friction and collision between the calcined product and the inner wall of the pulverizer are reduced, further better reducing the content of metal substances in the modified cathode material; and because talcum powder can play a role in modified coating or doping in the modification of the cathode material, that is, talcum powder will not become an impurity of the cathode material after being added to the calcined product of the cathode material for auxiliary crushing and pulverization, and talcum powder, as a modifying substance, realizes full mixing with the cathode material during the crushing and pulverization of the cathode material. Therefore, adding talcum powder when crushing the calcined product of the cathode material eliminates the pre-stirring and mixing process of the modifying substance and the cathode material in the preparation process of the modified cathode material, effectively accelerating the preparation efficiency of the modified cathode material and improving the performance of the cathode material.

[0043] It should be noted that if only powder or lubricant is added to the calcined product in the early stage, the powder or lubricant will be more doped in the calcined product, mainly for assisting grinding or reducing the collision intensity of the calcined product on the jaw crusher and the roll crusher during collision. However, the calcined product will still have more friction and collision with the jaw crusher and the roll crusher respectively, so it is difficult to effectively remove the metal substances in the cathode material. Therefore, in this application, mixing talcum powder with the calcined product not only because talcum powder has good fluidity, can better assist grinding or reduce the collision intensity of the calcined product on the jaw crusher and the roll crusher during collision, and the hygroscopicity of talcum powder is poor, avoiding the increase of moisture in the cathode material, but also because talcum powder will quickly adhere to the inner wall of the jaw crusher or the roll crusher after entering the jaw crusher or the roll crusher, thereby making the calcined product more indirectly friction and collide with the inner wall of the jaw crusher or the roll crusher, thus better reducing the friction and collision between the calcined product and the inner wall of the pulverizer, and further reducing the content of metal substances in the modified cathode material.

[0044] In one embodiment, talcum powder in an amount of 8 to 15 parts by mass and calcined product in an amount of 85 to 92 parts by mass are obtained. It can be understood that when there is too much powder doped in the calcined product, the powder will break the calcined product. Therefore, the talcum powder is 8 to 15 parts, and the calcined product is 85 to 92 parts, which preferably ensures the rapid decrease in the particle size of the calcined product, and preferably ensures the indirect friction between the talcum powder and the jaw crusher and the roll crusher respectively and the calcined product, and further preferably ensures the reduction of the frictional collision between the calcined product and the inner wall of the pulverizer, and preferably realizes the reduction of the content of metal substances in the modified cathode material.

[0045] In one embodiment, talcum powder in an amount of 10 to 12 parts by mass and calcined product in an amount of 88 to 90 parts by mass are obtained. It can be understood that when the talcum powder is 10 to 12 parts and the calcined product is 88 to 90 parts, it better ensures the rapid decrease in the particle size of the calcined product, and preferably ensures the reduction of the frictional collision between the calcined product and the inner wall of the pulverizer, and preferably realizes the reduction of the content of metal substances in the modified cathode material.

[0046] In one embodiment, the talcum powder includes SiO2, MgO, Al2O3 and impurities, which preferably realizes the function of modified coating or doping that the talcum powder can play in the modification of the cathode material.

[0047] In one embodiment, the talcum powder includes the following components in parts by mass: SiO2 50 to 70 parts; MgO 8 to 35 parts; Al2O3 0 to 1 part; impurities 4 to 10 parts, which preferably realizes the function of modified coating or doping that the talcum powder can play in the modification of the cathode material, and preferably ensures the adhesion of the talcum powder to the inner walls of the jaw crusher and the roll crusher, and further preferably ensures the indirect friction between the talcum powder and the jaw crusher and the roll crusher respectively and the calcined product, and further preferably ensures the reduction of the frictional collision between the calcined product and the inner wall of the pulverizer, and preferably realizes the reduction of the content of metal substances in the modified cathode material.

[0048] In one embodiment, the impurities include bound water, CaO and Fe2O3, ensuring less influence on the properties of the cathode material.

[0049] In one embodiment, the loss on ignition of the impurities is 4.5% to 6%, ensuring less influence on the properties of the cathode material.

[0050] In one embodiment, the D50 of the talcum powder is 3 μm to 20 μm, which preferably realizes the effective adhesion of the talcum powder to the inner walls of the jaw crusher and the roll crusher, and ensures the full mixing, doping modification or coating modification of the talcum powder and the calcined product.

[0051] In one embodiment, the particle size D90 of the talcum powder is 6 μm to 15 μm, which further preferably realizes the effective adhesion of the talcum powder to the inner walls of the jaw crusher and the roll crusher, and ensures the sufficient mixing, doping modification or coating modification of the talcum powder and the calcined material.

[0052] In one embodiment, the particle size D50 of the talcum powder is 7 μm to 12 μm, which further preferably realizes the effective adhesion of the talcum powder to the inner walls of the jaw crusher and the roll crusher, and ensures the sufficient mixing, doping modification or coating modification of the talcum powder and the calcined material.

[0053] In one embodiment, the particle size D90 of the talcum powder is 8 μm to 10 μm, which further preferably realizes the effective adhesion of the talcum powder to the inner walls of the jaw crusher and the roll crusher, and ensures the sufficient mixing, doping modification or coating modification of the talcum powder and the calcined material.

[0054] In one embodiment, the particle size of the calcined material is 30 mm to 100 mm. When the particle size D50 of the talcum powder is 3 μm to 20 μm, the particle size of the calcined material is coordinated to be 30 mm to 100 mm, which preferably forms a particle size distribution, preferably improves the powder fluidity, reduces the friction on the inner walls of the jaw crusher and the roll crusher, and further reduces the content of metal substances in the modified cathode material.

[0055] In one embodiment, the particle size of the calcined material is 30 mm to 98.7 mm, which better coordinates with the particle size D50 of the talcum powder being 3 μm to 20 μm to form a particle size distribution, better improves the powder fluidity, reduces the friction on the inner walls of the jaw crusher and the roll crusher, and further reduces the content of metal substances in the modified cathode material.

[0056] In one embodiment, the particle size of the calcined material is 72.1 mm to 85.6 mm, which better coordinates with the particle size D50 of the talcum powder being 3 μm to 20 μm to form a particle size distribution, better improves the powder fluidity, reduces the friction on the inner walls of the jaw crusher and the roll crusher, and further reduces the content of metal substances in the modified cathode material.

[0057] In one embodiment, the particle size of the first crushed material is 2 mm to 10 mm, which coordinates with the subsequent roll crusher to ensure the rapid crushing of the first crushed material.

[0058] In one embodiment, the particle size of the first crushed material is 2 mm to 8 mm, which better coordinates with the subsequent roll crusher to ensure the rapid crushing of the first crushed material.

[0059] In one embodiment, the particle size of the first crushed material is 3 mm to 8 mm, which better matches the subsequent roll crusher and ensures the rapid crushing of the first crushed material.

[0060] In one embodiment, the particle size of the second crushed material is 1 μm to 50 μm, which matches the subsequent crusher and ensures the rapid crushing of the second crushed material.

[0061] In one embodiment, the particle size of the second crushed material is 9 μm to 47 μm, which better matches the subsequent crusher and ensures the rapid crushing of the second crushed material.

[0062] In one embodiment, the particle size of the second crushed material is 1 μm to 12 μm, which better matches the subsequent crusher and ensures the rapid crushing of the second crushed material.

[0063] In one embodiment, the particle size of the second crushed material is 7 μm to 33 μm, which better matches the subsequent crusher and ensures the rapid crushing of the second crushed material.

[0064] In one embodiment, the particle size of the second crushed material is 11 μm to 47 μm, which better matches the subsequent crusher and ensures the rapid crushing of the second crushed material.

[0065] In one embodiment, the cathode material is the cathode material NCM811. It can be understood that the cathode material NCM811 is a high-nickel ternary cathode material.

[0066] In one embodiment, before the step of transporting the second crushed material to the crusher for crushing operation and after the step of feeding the first crushed material into the roll crusher for the second crushing operation, the crushing method based on the modified cathode material further includes the following steps: performing a vibration treatment on the jaw crusher and the roll crusher to make the talcum powder attached to the stacked jaw crusher and roll crusher detach from the jaw crusher and the roll crusher. It can be understood that in the jaw crusher and the roll crusher, the calcined materials are directly added, and the loss of talcum powder is mainly due to the talcum powder attached to the inner walls of the jaw crusher and the roll crusher. Therefore, the talcum powder in the jaw crusher and the roll crusher is relatively easy to collect through vibration, which better realizes the controllability of the content of talcum powder in the calcined material, and thus is beneficial to the doping modification and coating modification of the cathode material.

[0067] In one embodiment, the second crushed material is transported through a 3m to 5m pipeline to a crusher for crushing operation. It can be understood that the loss of talcum powder in the jaw crusher and roll crusher is relatively easy to control. However, when the second crushed material is transported to the crusher, it is generally transported by belt or pipeline, making it difficult to control the loss of talcum powder by means such as vibration. Therefore, in this application, in order to ensure the controllability of the content of talcum powder in the cathode material, the second crushed material is transported through a 3m to 5m pipeline to a crusher for crushing operation, that is, the loss of talcum powder is controlled by the distance of the transportation line, which better realizes the effective control of the content of talcum powder in the cathode material and is beneficial to the doping modification and coating modification of the cathode material.

[0068] In one embodiment, the crusher is a jet mill or a mechanical crusher, which is beneficial to the further effective crushing of the second crushed material and ensures the crushing effect of the calcined material.

[0069] In one embodiment, the second crushed material is pneumatically transported through a 3m to 5m pipeline to a jet mill for crushing operation. It can be understood that pneumatic transportation can reduce the residue of talcum powder and cathode material in the pipeline, thereby reducing the waste of talcum powder and cathode material.

[0070] In one embodiment, the second crushed material is pneumatically transported through a 3m to 5m pipeline to a mechanical crusher for crushing operation.

[0071] In one embodiment, the second crushed material is transported through a 3m to 5m belt pipeline to a mechanical crusher for crushing operation. It can be understood that although pneumatic transportation can better reduce the waste of talcum powder and cathode material in the pipeline, the transportation efficiency of the second crushed material by pneumatic transportation is relatively low. In order to further improve the transportation efficiency of the second crushed material, the belt transportation method is used to transport the second crushed material.

[0072] In one embodiment, the second crushed material is transported through a 3m to 5m belt pipeline to a jet mill for crushing operation.

[0073] In one embodiment, the second crushed material is transported to the crusher for crushing operation by combining pneumatic transportation and belt transportation, which not only reduces the waste of talcum powder and cathode material, but also improves the transportation efficiency of the second crushed material.

[0074] This application also provides a preparation method of a modified cathode material. One implementation manner of the preparation method of the modified cathode material includes the crushing method of the modified cathode material in any of the above embodiments.

[0075] In one embodiment, the preparation method of the modified cathode material includes some or all of the following steps:

[0076] Obtaining raw materials for positive electrode materials;

[0077] Mixing the raw materials;

[0078] The mixed raw materials are sintered to obtain a calcined product of the positive electrode material;

[0079] The calcined product is crushed by using the crushing method based on the modified positive electrode material of any of the above embodiments;

[0080] Demagnetizing the calcined material after the crushing process;

[0081] The calcined product after the demagnetization treatment is subjected to solid phase coating treatment to obtain a modified positive electrode material.

[0082] In the above-mentioned method for preparing the modified positive electrode material, talcum powder is added when the calcined positive electrode material is crushed, which alleviates the problem of more metal substances being mixed into the positive electrode material due to more collision and friction between the calcined material and the machine during crushing, so that the mixing of metal substances is processed in the previous step that may cause more metal substances to be mixed, that is, the talcum powder is better attached to the jaw crusher and the roller crusher, reducing the friction between the calcined material and the inner wall of the jaw crusher and the inner wall of the roller crusher, thereby better reducing the content of metal substances in the modified positive electrode material, and then further demagnetizing the calcined material after the crushing treatment, further reducing the content of magnetic substances in the calcined material; in addition, the pre-mixing process of the modified material and the positive electrode material in the preparation process of the modified positive electrode material is eliminated, that is, the mixing of talcum powder and the positive electrode material is completed during the crushing process, which effectively accelerates the preparation efficiency of the modified positive electrode material and better ensures the performance of the positive electrode material.

[0083] It should be noted that the metal substances in the positive electrode material, such as iron and copper, especially copper, need to be implemented with more complex equipment in the subsequent demagnetization treatment. However, even so, it is still difficult to achieve a good removal effect of the metal substances in the positive electrode material. That is to say, if the increase of metal substances is not effectively controlled during the preparation of the positive electrode material, even if a large number of steps are added later to remove the metal substances in the positive electrode material, it is difficult to achieve an effective reduction in the content of metal substances in the positive electrode material. Therefore, in the present application, the metal substances are controlled when the calcined positive electrode material is crushed, that is, talcum powder is mixed and crushed together with the calcined material, which effectively reduces the collision and friction of the jaw crusher, roller crusher and pulverizer during crushing, thereby better reducing the content of metal substances in the modified positive electrode material.

[0084] In one embodiment, the solid-phase coating treatment of the calcined product after demagnetization treatment is specifically as follows: Add the calcined product after demagnetization treatment into the ball mill pot of the ball mill. Then, add grinding balls with a mass twice that of the material into the ball mill pot, and ball mill at a rotation speed of 200 r / min to 210 r / min for 1.5 h ± 0.5 h, and then take out the grinding balls; sinter the ball-milled calcined product at 800 °C ± 15 °C, and then cool it with the furnace; crush the cooled calcined product with a crusher to obtain a talc powder solid-phase coated cathode material with a particle size D50 of 8 μm to 12 μm, effectively realizing the talc powder coating modification of the cathode material.

[0085] In one embodiment, before the step of performing solid-phase coating treatment on the calcined product after demagnetization treatment and after the step of performing demagnetization treatment on the calcined product after crushing treatment, the preparation method of the modified cathode material further includes the following steps: performing drying treatment on the calcined product after demagnetization treatment, which is beneficial to the solid-phase coating modification of the cathode material.

[0086] In one embodiment, after the step of performing solid-phase coating treatment on the calcined product after demagnetization treatment, the preparation method of the modified cathode material further includes the following steps: performing washing and drying treatment on the calcined product after solid-phase coating treatment.

[0087] In one embodiment, after the step of performing washing and drying treatment on the calcined product after solid-phase coating treatment, the preparation method of the modified cathode material further includes the following steps: performing crushing, grading, batch mixing and packaging on the calcined product after washing and drying treatment.

[0088] In one embodiment, the calcined product after crushing treatment is transported to a magnetic separator through a pipeline of 3 m to 5 m for demagnetization treatment, which preferably ensures the controllability of the talc powder content.

[0089] In one embodiment, the operation of transporting the calcined product to the magnetic separator is the same as the operation of transporting the second crushed material to the crusher.

[0090] This application also provides a modified cathode material, which is prepared by using the preparation method of the modified cathode material according to any one of the above embodiments.

[0091] Compared with the prior art, the present invention has at least the following advantages:

[0092] 1. The crushing method of the modified cathode material according to the present invention adds talcum powder when crushing the calcined product of the cathode material. Since the particle size of the calcined product of the cathode material in the jaw crusher and the roll crusher is relatively large, and talcum powder can adhere well to the jaw crusher and the roll crusher, thus talcum powder can preferably reduce the friction between the calcined product and the inner walls of the jaw crusher and the roll crusher respectively, that is, reduce the wear of the cathode material on the inner walls of the jaw crusher and the roll crusher respectively, and then preferably ensure the service life of the inner walls of the jaw crusher and the roll crusher, and preferably reduce the content of metal substances in the modified cathode material; in addition, after the calcined product passes through the jaw crusher and the roll crusher, it can preferably ensure the reduction of the particle size of the calcined product, and then the jaw crusher and the roll crusher are used in combination with the pulverizer, that is, preferably ensure quickly reaching the required crushing particle size of the calcined product, and because the calcined product mixed with talcum powder has good fluidity, thus reducing the friction and collision between the calcined product and the inner wall of the pulverizer, and further preferably reducing the content of metal substances in the modified cathode material;

[0093] 2. The crushing method of the modified cathode material according to the present invention, since talcum powder can play a role in modified coating or doping in the modification of the cathode material, that is, talcum powder will not become an impurity of the cathode material after being added to the calcined product of the cathode material for auxiliary crushing and pulverization, and talcum powder, as a modifying substance, realizes full mixing with the cathode material during the crushing and pulverization of the cathode material. Therefore, adding talcum powder when crushing the calcined product of the cathode material eliminates the pre-stirring and mixing process of the modifying substance and the cathode material in the preparation process of the modified cathode material, effectively improves the preparation efficiency of the modified cathode material, and realizes the improvement of the performance of the cathode material.

[0094] The following are some examples. It should be noted that the following examples do not exhaust all possible situations, and the materials used in the following examples can be obtained from commercial channels without special instructions.

[0095] Example 1

[0096] The devices used for crushing are a jaw crusher, a roll crusher and a jet mill. Among them, the discharge port of the jaw crusher is located above the feed port of the roll crusher, and the output end of the roll crusher is connected to the jet mill by a pipeline through belt transportation. The length of the pipeline is 3.2 m. The calcined product and talcum powder are put into the jaw crusher for crushing to form the first crushed material, then enter the roll crusher for crushing to form the second crushed material, and then are transported by pipeline to the jet mill for pulverization. The output end of the jet mill is successively connected with a cyclone separator and a dust collector to collect the pulverized material, and then is transported to a magnetic separator through a pipeline for magnetic separation, and then enters the solid-phase coating process.

[0097] The solid-phase coating process includes: adding the above-mentioned materials into the ball mill tank of a ball mill, then adding grinding balls with a mass twice that of the materials, taking them out after ball milling at a speed of 200 r / min for 2 h; sintering the ball-milled materials at 800 °C and then cooling them in the furnace; crushing the cooled materials with a crusher to obtain talc powder solid-phase coated NCM811 with a particle size D50 of 10 μm; after the coating is completed, washing, drying and other processes are carried out on the coated NCM811 to prepare the finished product.

[0098] The addition amount of the above-mentioned talc powder is 8%, and the talc powder components include 52 g of SiO2, 8 g of MgO and 5 g of inevitable impurity components (including bound water, CaO and Fe2O3, and the loss on ignition is 5.1%), and the particle size of the talc powder is D50 = 4 μm and D90 = 8 μm.

[0099] The particle size of the calcined product is 72.1 mm; the particle size of the first crushed material is 10 mm, and the particle size of the second crushed material is 47 μm.

[0100] Example 2

[0101] The devices used for crushing are jaw crushers, roll crushers and mechanical pulverizers. Among them, the discharge port of the jaw crusher is arranged above the feed port of the roll crusher, and the output end of the roll crusher is transported to the mechanical pulverizer through a pipeline by belt and pneumatic means. The pipeline length is 3.8 m. The calcined product and talc powder are put into the jaw crusher for crushing to form the first crushed material, and then enter the roll crusher for crushing to form the second crushed material, and then are transported through the pipeline to the mechanical pulverizer for pulverization. The output end of the mechanical pulverizer is successively connected with a cyclone separator and a dust collector to collect the pulverized materials, and then are transported through the pipeline to a magnetic separator for magnetic separation, and then enter the solid-phase coating process. The solid-phase coating process includes: adding the above-mentioned materials into the ball mill tank of a ball mill, then adding grinding balls with a mass twice that of the materials, taking them out after ball milling at a speed of 210 r / min for 2 h; sintering the ball-milled materials at 810 °C and then cooling them in the furnace; crushing the cooled materials with a crusher to obtain talc powder solid-phase coated NCM811 with a particle size D50 of 10 μm; after the coating is completed, washing, drying and other processes are carried out on the coated NCM811 to prepare the finished product.

[0102] The addition amount of the above-mentioned talc powder is 10%, and the talc powder components include 70 g of SiO2, 34 g of MgO and 8 g of inevitable impurity components (including bound water, CaO and Fe2O3, and the loss on ignition is 4.5%), and the particle size of the talc powder is D50 = 10 μm and D90 = 15 μm.

[0103] The particle size of the calcined product is 75 mm; the particle size of the first crushed material is 6 mm, and the particle size of the second crushed material is 9 μm.

[0104] Example 3

[0105] The devices used for crushing are jaw crushers, roll crushers and mechanical pulverizers. Among them, the discharge port of the jaw crusher is set above the feed port of the roll crusher. The output end of the roll crusher and the mechanical pulverizer are transported by pipeline with belt and pneumatic power. The pipeline length is 4.0 m. The calcined material and talcum powder are put into the jaw crusher for crushing to form the first crushed material, then enter the roll crusher for crushing to form the second crushed material, and then are transported by pipeline to the mechanical pulverizer for pulverization. The output end of the mechanical pulverizer is successively connected with a cyclone separator and a dust collector to collect the pulverized material, and then is transported by pipeline to the magnetic separator for magnetic separation, and then enters the solid-phase coating process. The solid-phase coating process includes: adding the above-mentioned material into the ball mill tank of the ball mill, then adding grinding balls with twice the mass of the material, and taking out the material after ball milling at a speed of 210 r / min for 2 h; sintering the ball-milled material at 790 °C and then cooling it in the furnace; crushing the cooled material with a crusher to obtain talcum powder with a particle size D50 of 8 μm for solid-phase coating of NCM811; after the coating is completed, washing, drying and other processes are carried out on the coated NCM811 to prepare the finished product.

[0106] The addition amount of the above-mentioned talcum powder is 12%. The talcum powder components include 67 g of SiO2, 29 g of MgO, 1 g of Al2O3 and 8 g of inevitable impurity components (including bound water, CaO and Fe2O3, and the loss on ignition is 6%). The particle size of the talcum powder is D50 = 8 μm and D90 = 11 μm.

[0107] The particle size of the calcined material is 72.1 mm; the particle size of the first crushed material is 8 mm, and the particle size of the second crushed material is 33 μm.

[0108] Example 4

[0109] The devices used for crushing are jaw crushers, roll crushers and mechanical pulverizers. Among them, the discharge port of the jaw crusher is set above the feed port of the roll crusher. The output end of the roll crusher and the mechanical pulverizer are transported by pipeline with pneumatic power. The pipeline length is 4.5 m. The calcined material and talcum powder are put into the jaw crusher for crushing to form the first crushed material, then enter the roll crusher for crushing to form the second crushed material, and then are transported by pipeline to the mechanical pulverizer for pulverization. The output end of the mechanical pulverizer is successively connected with a cyclone separator and a dust collector to collect the pulverized material, and then is transported by pipeline to the magnetic separator for magnetic separation, and then enters the solid-phase coating process. The solid-phase coating process includes: adding the above-mentioned material into the ball mill tank of the ball mill, then adding grinding balls with twice the mass of the material, and taking out the material after ball milling at a speed of 205 r / min for 2 h; sintering the ball-milled material at 815 °C and then cooling it in the furnace; crushing the cooled material with a crusher to obtain talcum powder with a particle size D50 of 10 μm for solid-phase coating of NCM811; after the coating is completed, washing, drying and other processes are carried out on the coated NCM811 to prepare the finished product.

[0110] The addition amount of the talcum powder described above is 10%, and the talcum powder components include 51 g of SiO2, 8 g of MgO, 1 g of Al2O3, and 10 g of inevitable impurity components (including bound water, CaO, and Fe2O3, with a loss on ignition of 4.5%). The particle size of the talcum powder is D50 = 5 μm and D90 = 9 μm.

[0111] The particle size of the calcined material is 100 mm; the particle size of the first crushed material is 8 mm, and the particle size of the second crushed material is 25 μm.

[0112] Comparative Example 1

[0113] The devices used for crushing are a jaw crusher, a roll crusher, and a mechanical pulverizer. Among them, the discharge port of the jaw crusher is arranged above the feed port of the roll crusher. The output end of the roll crusher and the mechanical pulverizer are transported by pipeline with belt and pneumatic power. The pipeline length is 3.8 m. The calcined material is put into the jaw crusher for crushing to form the first crushed material, then enters the roll crusher for crushing to form the second crushed material, and then is transported by pipeline to the mechanical pulverizer for pulverization. The output end of the mechanical pulverizer is successively connected with a cyclone separator and a dust collector to collect the pulverized material, and then is transported to a magnetic separator through a pipeline for magnetic separation, and then enters the solid-phase coating process. The solid-phase coating process includes: premixing the above-mentioned material and talcum powder, then adding it into the ball mill tank of the ball mill, and then adding grinding balls with twice the mass of the material, and taking it out after ball milling at a speed of 210 r / min for 2 h; sintering the ball-milled material at 810 °C and then cooling it in the furnace; crushing the cooled material with a crusher to obtain talcum powder solid-phase coated NCM811 with a particle size D50 of 10 μm; after the coating is completed, washing, drying and other processes are carried out on the coated NCM811 to prepare the finished product.

[0114] The above-mentioned talcum powder is the talcum powder commonly available in the market. The addition amount of the talcum powder is 10%, and the particle size of the talcum powder is D50 = 10 μm and D90 = 15 μm.

[0115] The particle size of the calcined material is 75 mm; the particle size of the first crushed material is 6 mm, and the particle size of the second crushed material is 9 μm.

[0116] Comparative Example 2

[0117] The devices used for crushing are jaw crushers, roll crushers, and mechanical pulverizers. Among them, the discharge port of the jaw crusher is located above the feed port of the roll crusher. The output end of the roll crusher and the mechanical pulverizer are transported by pipeline through belt and pneumatic means. The pipeline length is 3.8 m. The calcined material is put into the jaw crusher for crushing to form the first crushed material, then enters the roll crusher for crushing to form the second crushed material, and then is transported by pipeline to the mechanical pulverizer for pulverization. The output end of the mechanical pulverizer is successively connected with a cyclone separator and a dust collector to collect the pulverized material, and then is transported to a magnetic separator through a pipeline for magnetic separation, and then enters the solid-phase coating process. The solid-phase coating process includes: premixing the above-mentioned material with 70 g of SiO2 and 34 g of MgO. Among them, the particle sizes of SiO2 and MgO are: D50 = 10 μm, D90 = 15 μm; then, it is added into the ball mill pot of the ball mill, and then grinding balls with twice the mass of the material are added, and it is taken out after ball milling at a speed of 210 r / min for 2 h; the ball-milled material is sintered at 810 °C and then cooled with the furnace; the cooled material is crushed by a crusher to obtain talc powder with a particle size D50 of 10 μm for solid-phase coating of NCM811; after coating, the coated NCM811 is washed, dried and other processes to prepare the finished product.

[0118] The particle size of the calcined material is 75 mm; the particle size of the first crushed material is 6 mm, and the particle size of the second crushed material is 9 μm.

[0119] The modified cathode materials of Examples 1 to 4 and the modified cathode materials of Comparative Examples 1 to 2 are detected below. Relevant test data are recorded during the preparation of the modified cathode materials. See Table 1 below. Among them, after each test, the pipeline is cleaned by air blowing to avoid material residue affecting the test data.

[0120] Table 1: Contents of corresponding components in examples and comparative examples

[0121]

[0122] [Note] Ten samples are randomly selected from the samples for qualitative detection of copper.

[0123] It should be noted that the talc powder content is detected by detecting the MgO content and then converting it in combination with the proportion of MgO content in the original added talc powder. For example: the detected MgO content in the discharge is a%; the MgO content in the added talc powder is b%, then the converted talc powder content in the discharge is a% / b%. In addition, the talc powder will be demagnetized during the crushing process, that is, before being put into the jaw crusher together with the calcined material. The capacity retention rate is the capacity retention rate after 200 charge-discharge cycles at 1C at room temperature of 25 °C. The qualitative detection method of copper is a general copper colorimetric detection, and whether copper is contained is judged by color change during the detection process.

[0124] As can be seen from Table 1, adding talcum powder synchronously when the cathode material is crushed effectively reduces the contents of iron and copper in the modified cathode material, especially in Examples 2 to 3. Moreover, the controllability of talcum powder is relatively high. After the talcum powder and the cathode material are crushed together, solid-phase coating is carried out immediately, and the obtained talcum powder solid-phase coated NCM811 has good specific capacity and capacity retention rate, especially in Examples 2 to 3. The specific capacity and capacity retention rate of the cathode material in Comparative Example 2 are poorer than those of the cathode materials in Examples 1-4, probably because: 1. Some impurities in the talcum powder have positive effects; 2. The magnetic substances in the materials are not removed thoroughly enough; 3. The influence of copper.

[0125] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A crushing method based on a modified cathode material, characterized in that, It includes the following steps: Obtain talcum powder with a mass fraction of 8 parts to 15 parts and a calcined product with a mass fraction of 85 parts to 92 parts, wherein the particle size D50 of the talcum powder is 3 μm to 20 μm; Put the talcum powder and the calcined product into a jaw crusher for a first crushing operation, so that the talcum powder adheres to the inner wall of the jaw crusher and obtain a first crushed material; Put the first crushed material into a roll crusher for a second crushing operation, so that the talcum powder adheres to the inner wall of the roll crusher and obtain a second crushed material; Transport the second crushed material to a pulverizer for a pulverizing operation.

2. The crushing method based on the modified cathode material according to claim 1, wherein The talcum powder includes SiO2, MgO, Al2O3 and impurities.

3. The crushing method based on the modified cathode material according to claim 1, characterized in that, The talcum powder includes the following components in mass fractions:

4. The crushing method based on the modified cathode material according to claim 1, wherein The particle size D90 of the talcum powder is 6 μm to 15 μm.

5. The crushing method based on the modified cathode material according to claim 1, wherein The particle size of the calcined product is 30 mm to 100 mm; and / or, The particle size of the first crushed material is 2 mm to 10 mm; and / or, The particle size of the second crushed material is 1 μm to 50 μm.

6. The crushing method based on the modified cathode material according to claim 1, characterized in that, The cathode material is cathode material NCM811.

7. The crushing method based on the modified cathode material according to any one of claims 1 to 6, characterized in that, Transport the second crushed material through a pipeline of 3 m to 5 m to a pulverizer for a pulverizing operation.

8. A preparation method of a modified cathode material, characterized in that, It includes the crushing method based on the modified cathode material according to any one of claims 1 to 7.

9. A modified cathode material, characterized in that, It is prepared by using the preparation method based on the modified cathode material described in claim 8.

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