A method for pretreating a lithium ion battery cathode material

Abstract

The application provides a lithium ion battery positive electrode material pretreatment method, according to a set temperature rising procedure, the positive electrode material is heated to a target temperature; at the target temperature, the positive electrode material is treated by dynamic airflow regulation in a preset atmosphere, and first intensity oscillation is carried out in the heat preservation treatment process; after cooling to room temperature, the positive electrode material is subjected to second intensity oscillation, so that the powder on the surface of the positive electrode material is separated from the current collector; wherein the oscillation frequency and amplitude of the second intensity oscillation are higher than those of the first intensity oscillation. Through sufficient heat treatment, the binder is completely disabled, and combined with the stepwise oscillation, the positive electrode material is efficiently and completely separated from the current collector, and at the same time, due to the loosening of the interface in advance, the positive electrode material particle breakage rate is reduced in the oscillation process; a controllable temperature rising procedure is adopted, the cracking and structural damage are reduced, and no organic chemical solvent is needed in the whole process, so that the environmental protection cost is low.

Description

Technical Field

[0001] This invention relates to the field of waste battery recycling, and specifically to a method for pretreatment of lithium-ion battery cathode materials. Background Technology

[0002] With the widespread application of lithium-ion batteries, their recycling and resource reuse after retirement has become an important issue. Cathode materials are one of the most recyclable components of batteries, and efficient and environmentally friendly pretreatment (i.e., peeling them off from the current collector aluminum foil) is a key prerequisite for subsequent recycling.

[0003] Currently, commonly used pretreatment methods have the following shortcomings: First, mechanical stripping easily leads to the breakage of cathode material particles, which mix with current collector fragments, reducing the purity and electrochemical performance of the recovered material. Second, solvent dissolution relies on organic solvents to remove binders, resulting in problems such as solvent volatilization polluting the environment, difficult residue removal, and the need for complex recovery devices, making it neither environmentally friendly nor economically viable. Third, while heat treatment avoids chemical pollution, it generally suffers from insufficient isothermal time, leading to incomplete binder decomposition and low stripping rates. Furthermore, traditional single heat treatment or rough vibration can easily damage the material. Therefore, there is an urgent need to develop a pretreatment method that is versatile, has a high stripping rate, is environmentally friendly, and can effectively protect the physicochemical structure of the cathode material. Summary of the Invention

[0004] In view of the aforementioned problems, this application is proposed to provide a method for pretreating lithium-ion battery cathode materials to overcome or at least partially solve the aforementioned problems, comprising: A method for pretreating lithium-ion battery cathode materials, used to recycle waste lithium-ion battery cathode materials, wherein the powder on the surface of the cathode material is bonded to a current collector by a binder, comprising the following steps: The positive electrode material is heated to the target temperature according to the set heating program; At the target temperature, the positive electrode material is subjected to heat preservation treatment in a preset atmosphere by dynamic airflow control, and a first intensity oscillation is performed during the heat preservation treatment process; After cooling to room temperature, the positive electrode material is subjected to a second intensity of oscillation to cause the powder on the surface of the positive electrode material to peel off from the current collector; wherein the oscillation frequency and amplitude of the second intensity oscillation are both higher than those of the first intensity oscillation.

[0005] Furthermore, the set heating program is a uniform heating, with an initial temperature of 25±5℃, a heating rate of 5℃-20℃ / min, and a target temperature of 300-600℃.

[0006] Furthermore, the set heating program is a gradient heating, heating to 100-200℃ at a rate of 5-20℃ / min and holding for 2-4 hours; then heating to 200-300℃ and holding for 3-6 hours; finally heating to 400-600℃ and holding for 4-8 hours.

[0007] Furthermore, the heating device is a muffle furnace or a tubular furnace heating device.

[0008] Furthermore, the heating device is equipped with an electrostatic adsorption plate to adsorb trace amounts of binder carbon powder remaining in the airflow during the heating and heat preservation process.

[0009] Furthermore, the preset atmosphere is oxygen, or a mixture of oxygen, nitrogen, and ozone.

[0010] Furthermore, the dynamic airflow control uses a first flow rate for ventilation during the heating phase and a second flow rate for ventilation during the heat preservation phase; wherein the first flow rate is higher than the second flow rate.

[0011] Furthermore, the heat preservation treatment time is 6-14 hours.

[0012] Furthermore, the step of performing the first intensity vibration during the heat preservation process includes: During the last 1-2 hours of the heat preservation process, a first-intensity vibration treatment is carried out simultaneously. The vibration frequency of the first-intensity vibration is 50-100Hz, and the amplitude is 2-5mm.

[0013] Furthermore, the second intensity oscillation has an oscillation frequency of 150-200Hz and an amplitude of 8-12mm.

[0014] This application has the following advantages: In the embodiments of this application, addressing the problems of poor versatility, insufficient environmental friendliness, and easy material damage in existing technologies, this application provides a solution for heat treatment and vibration-assisted peeling. Specifically, the positive electrode material is heated to a target temperature according to a set heating program; at the target temperature, the positive electrode material is kept warm in a preset atmosphere through dynamic airflow control, and a first intensity vibration is performed during the heat preservation process; after cooling to room temperature, the positive electrode material is subjected to a second intensity vibration to peel the powder on the surface of the positive electrode material from the current collector; wherein, the vibration frequency and amplitude of the second intensity vibration are higher than those of the first intensity vibration. By fully heat-treating to completely disable the binder, combined with step-like vibration, the positive electrode material is efficiently and completely peeled from the current collector. At the same time, due to the early loosening of the interface, the breakage rate of the positive electrode material particles is reduced during the vibration process, avoiding material damage caused by high-intensity vibration in the later stage; the use of a controllable heating program reduces cracking and structural damage caused by thermal stress, solves the problem of poor versatility of traditional methods, and does not require the use of organic chemical solvents throughout the process, resulting in low environmental protection and cost. Attached Figure Description

[0015] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the steps of a lithium-ion battery cathode material pretreatment method provided in an embodiment of this application. Detailed Implementation

[0017] To make the objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0018] The inventors, through analysis of existing technologies, discovered that: 1. Some pretreatment processes have insufficient isothermal time (usually <8h), which fails to fully deactivate the binder within the electrode, making subsequent material separation from the current collector difficult and resulting in a low separation rate; 2. They are not environmentally friendly, as some binder removal methods rely on organic solvents, leading to solvent volatilization pollution, difficult-to-clean residues, and the need for additional solvent recovery devices, increasing the complexity of the production process and environmental costs; 3. Conventional methods easily cause the cathode material to break and become mixed with the current collector, affecting the purity and electrochemical performance of subsequent materials.

[0019] Reference Figure 1 This application illustrates a method for pretreating lithium-ion battery cathode materials according to an embodiment of the present application, including the following steps: S110. Heat the positive electrode material to the target temperature according to the set heating program; S120. At the target temperature, the positive electrode material is kept warm in a preset atmosphere by dynamic airflow control, and a first intensity oscillation is performed during the warming process. S130. After cooling to room temperature, the positive electrode material is subjected to a second intensity oscillation to separate the powder on the surface of the positive electrode material from the current collector; wherein the oscillation frequency and amplitude of the second intensity oscillation are higher than those of the first intensity oscillation.

[0020] In the embodiments of this application, addressing the problems of poor versatility, insufficient environmental friendliness, and easy material damage in existing technologies, this application provides a solution of heat treatment and vibration-assisted peeling. By thoroughly heat-treating to completely disable the binder, combined with stepped vibration, the cathode material is efficiently and completely peeled from the current collector. Simultaneously, due to the pre-loosening of the interface, the breakage rate of cathode material particles is reduced during vibration, avoiding material damage caused by high-intensity vibration later. The controllable heating program reduces cracking and structural damage caused by thermal stress, solving the problem of poor versatility in traditional methods. Furthermore, the entire process requires no organic chemical solvents, resulting in environmental friendliness and low cost.

[0021] The following will further describe a method for pretreating lithium-ion battery cathode materials in this exemplary embodiment.

[0022] In one embodiment of the present invention, the specific process of "heating the positive electrode material to the target temperature according to the set heating program" in step S110 can be further described in conjunction with the following description.

[0023] The positive electrode material is placed in a heating device and heated to the target temperature according to a specific program. The heating device includes, but is not limited to, a muffle furnace or a tubular furnace. An electrostatic adsorption plate is installed in the heating device to adsorb trace amounts of binder carbon powder remaining in the gas flow, preventing it from mixing with the fine positive electrode powder and reducing impurities in the recycled material. The heating program is either gradient heating or uniform heating, and the binder is completely decomposed through precise control of the heating process.

[0024] As an example, when the heating program is a uniform heating process, the starting temperature is room temperature (25±5℃), the uniform heating rate is 5℃-20℃ / min, and the target temperature is 300-600℃.

[0025] As another example, when the heating program is a gradient heating, a three-stage gradient control mode is adopted: first, the temperature is increased to 100-200℃ at a rate of 5-20℃ / min and held for 2-4 hours; then the temperature is increased to 200-300℃ and held for 3-6 hours; finally, the temperature is increased to 400-600℃ and held for 4-8 hours.

[0026] In one embodiment of the present invention, the specific process of step S120, "at the target temperature, the positive electrode material is subjected to heat preservation treatment in a preset atmosphere by dynamic airflow control, and a first intensity oscillation is performed during the heat preservation treatment process," can be further described in conjunction with the following description.

[0027] At the target temperature, the positive electrode of the battery is kept at a constant temperature and subjected to low-intensity oscillation in a certain atmosphere through dynamic airflow control. By controlling the heating-oscillation coordinated timing, the overall stripping cycle can be shortened. At the same time, due to the early loosening of the interface, the breakage rate of the positive electrode material particles is reduced during the oscillation process, avoiding material damage caused by high-intensity oscillation in the later stage.

[0028] As an example, the heating atmosphere is a mixture of 10-100% oxygen and 0-90% nitrogen and ozone; the dynamic airflow control in this step is to use high flow rate (1-5L / min) during the heating stage and low flow rate (0.1-0.5L / min) during the heat preservation stage; the constant temperature heat preservation treatment time is 6-14h.

[0029] In one embodiment of the present invention, the specific process of step S130, which involves "after cooling to room temperature, subjecting the positive electrode material to a second intensity oscillation to cause the powder on the surface of the positive electrode material to peel off from the current collector; wherein the oscillation frequency and amplitude of the second intensity oscillation are both higher than those of the first intensity oscillation", can be further described in conjunction with the following description.

[0030] The cathode material is cooled using natural cooling or controlled-rate cooling to reduce cracking and particle breakage caused by thermal stress during cooling, thus better maintaining the crystal structure and physical property stability of the cathode material (such as lithium iron phosphate and ternary materials). The cooled cathode material is then removed and treated with high-intensity vibration to separate the powder and current collector from the surface of the cathode material. The separated battery cathode powder and current collector are then separated and collected. This invention requires no chemical solvents, is environmentally friendly and low-cost, is adaptable to various lithium battery cathode materials, has a high separation success rate and high efficiency, and is suitable for large-scale industrial lithium battery cathode pretreatment or recycling scenarios.

[0031] As an example, a controlled cooling rate of ≤10℃ / min was used. After cooling to room temperature, the low-intensity oscillation was immediately switched to a high-intensity oscillation module with an oscillation frequency of 150-200Hz and an amplitude of 8-12mm to complete the final stripping. Subsequently, the stripped battery positive electrode powder and current collector were separated by sieving with a 100-mesh sieve.

[0032] Example 1 1. Heating Treatment: The positive electrode material is placed in a muffle furnace and heated from room temperature to 500℃ at a uniform heating rate of 10℃ / min. Dynamic airflow control is used during the heating phase, with a flow rate of 3L / min. Simultaneously, the electrostatic adsorption plate (8kV) within the heating device is activated, and a near-infrared spectral sensor is installed to monitor the 1710cm² temperature in real time. -1 Absorbance of characteristic peaks of ester groups.

[0033] 2. Constant temperature and low-intensity oscillation: After heating to 500℃, a 21% oxygen-nitrogen mixed atmosphere is introduced, and the gas flow rate is switched to 0.3L / min. The constant temperature treatment is carried out for 10 hours. During the last 1.5 hours of constant temperature treatment, the low-intensity oscillation module is started simultaneously, with the oscillation frequency set to 80Hz and the amplitude to 3mm. The oscillation parameters are maintained according to the near-infrared sensor data to loosen the interface between the positive electrode material and the current collector.

[0034] 3. Cooling treatment: After the constant temperature period ends, a controllable cooling rate is adopted, with the cooling rate set at 8℃ / min, until the material temperature drops to room temperature.

[0035] 4. High-intensity oscillation and separation: After cooling, high-intensity oscillation is started with an initial frequency of 170Hz and an amplitude of 9mm; according to the sensor linkage control: when the absorbance is 0.2-0.6, the frequency is adjusted to 100Hz and the amplitude is 5mm, and when the absorbance is <0.2, it is stopped; a 100-mesh sieve is used to separate the positive electrode powder and the current collector, and the positive electrode powder with the binder completely degraded is obtained.

[0036] Example 2 1. Gradient heating treatment: The positive electrode material is placed in a tube furnace, and a three-stage gradient heating method is used: First stage: Heat to 150℃ at a rate of 10℃ / min, and hold for 3 hours; Second stage: Increase the temperature to 250℃ at a rate of 8℃ / min and hold for 4 hours; Third stage: Heat to 450℃ at a rate of 12℃ / min and hold for 5 hours; The entire heating process employs dynamic airflow control, with a ventilation rate of 3L / min. The electrostatic adsorption plate (7kV) and near-infrared spectral sensor are activated, and real-time monitoring is performed at 1710cm². - ¹Absorbance of the characteristic peak of the ester group.

[0037] 2. Isothermal and low-intensity oscillation: After heating to 450℃, a mixed atmosphere of 50% oxygen + 50% nitrogen is introduced, and the ventilation flow rate is switched to 0.2L / min. The total isothermal time is 12h. During the last 2h of isothermal control, the low-intensity oscillation module is started, with a frequency of 90Hz and an amplitude of 4mm. The parameters are maintained based on sensor data (absorbance > 0.6).

[0038] 3. Cooling process: After the constant temperature period ends, turn off the heating device and allow the room temperature to cool down naturally.

[0039] 4. High-intensity oscillation and separation: After cooling, high-intensity oscillation is started with an initial frequency of 170Hz and an amplitude of 9mm; according to the sensor linkage control: when the absorbance is 0.2-0.6, the frequency is adjusted to 100Hz and the amplitude is 5mm, and when the absorbance is <0.2, it is stopped; a 100-mesh sieve is used to separate the positive electrode powder and the current collector, and the positive electrode powder with the binder completely degraded is obtained.

[0040] Example 3 1. Heating Treatment: The positive electrode material was placed in a muffle furnace and heated from room temperature to 480℃ at a uniform heating rate of 15℃ / min; during the heating stage, the gas flow rate was 4L / min, the electrostatic adsorption plate was activated (voltage 6kV), and a near-infrared spectral sensor was installed to monitor the temperature at 1710cm² in real time. -1 Absorbance of characteristic peaks.

[0041] 2. Isothermal and low-intensity oscillation: After heating to 480℃, a mixed atmosphere of 50% oxygen + 50% nitrogen is introduced at a flow rate of 0.5L / min, and isothermal treatment is carried out for 14h; during the last hour of isothermal treatment, low-intensity oscillation is started at a frequency of 70Hz and an amplitude of 2mm, and the parameters are maintained according to the sensor data (absorbance > 0.6).

[0042] 3. Cooling treatment: After the constant temperature period ends, the temperature is reduced at a controlled rate of 10℃ / min to room temperature.

[0043] 4. High-intensity oscillation and separation: After cooling, high-intensity oscillation is started with an initial frequency of 170Hz and an amplitude of 8mm; according to the sensor linkage: when the absorbance is >0.6, the initial parameters are maintained; when it drops to 0.2-0.6, the frequency is adjusted to 110Hz and the amplitude to 6mm; when it is <0.2, the oscillation is stopped; the material is sieved through a 100-mesh sieve to obtain positive electrode powder with completely degraded binder.

[0044] Example 4 1. Heating Treatment: The positive electrode material is placed in a tube furnace and heated from room temperature to 520℃ at a uniform heating rate of 10℃ / min. During the heating stage, the gas flow rate is 2L / min. The electrostatic adsorption plate (voltage 8kV) and near-infrared spectral sensor are activated to focus on the oscillation area on the electrode surface and monitor the 1710cm² area in real time. -1 Absorbance of characteristic peaks of ester groups.

[0045] 2. Constant temperature and low-intensity oscillation: After heating to 520℃, a mixed atmosphere of 80% nitrogen and 20% oxygen was introduced at a flow rate of 0.35L / min, and the temperature was kept constant for 11 hours. During the last 1.5 hours of constant temperature, low-intensity oscillation was started with a frequency of 85Hz and an amplitude of 3mm.

[0046] 3. Cooling treatment: After the constant temperature period, a controllable cooling rate of 4℃ / min is adopted to ensure that the positive electrode material is cooled down to room temperature.

[0047] 4. High-intensity oscillation and separation: After cooling, high-intensity oscillation is started with an initial frequency of 185Hz and an amplitude of 10mm; according to the sensor linkage: when the absorbance is >0.6, the parameters are maintained; when it drops to 0.2-0.6, the frequency is adjusted to 110Hz and the amplitude to 7mm; when it is <0.2, the oscillation is stopped; the material is sieved through a 100-mesh sieve to obtain positive electrode powder with completely degraded binder.

[0048] Example 5 1. Heating Treatment: The lithium iron phosphate cathode material for energy storage was placed in a muffle furnace and heated from room temperature to 400℃ at a uniform heating rate of 12℃ / min. During the heating phase, the gas flow rate was 3.5L / min, and the electrostatic adsorption plate (voltage 7kV) and near-infrared spectral sensor were activated to monitor the temperature at 1710cm in real time. -1 Absorbance of characteristic peaks of ester groups.

[0049] 2. Isothermal and low-intensity oscillation: After heating to 400℃, air is introduced at a flow rate of 0.25L / min, and isothermal treatment is carried out for 9 hours; during the last 1.2 hours of isothermal treatment, low-intensity oscillation is started with a frequency of 65Hz and an amplitude of 2.5mm to adapt to the material characteristics at low temperature, and the parameters are maintained according to sensor data (absorbance > 0.6).

[0050] 3. Cooling process: After the constant temperature period ends, turn off the heating device and allow the room temperature to cool down naturally.

[0051] 4. High-intensity oscillation and separation: After cooling, high-intensity oscillation is started with an initial frequency of 165Hz and an amplitude of 8.5mm. According to the sensor linkage: when the absorbance is >0.6, the parameters are maintained; when it drops to 0.2-0.6, the frequency is adjusted to 100Hz and the amplitude is 5mm; when it is <0.2, the oscillation is stopped. The powder and the current collector are separated by sieving through a 100-mesh sieve to obtain positive electrode powder with the binder completely degraded.

[0052] Example 6 1. Heating Treatment: The positive electrode material was placed in a muffle furnace and heated from room temperature to 460℃ at a uniform heating rate of 18℃ / min; during the heating phase, the gas flow rate was 5L / min, and the electrostatic adsorption plate (voltage 9kV) and near-infrared spectral sensor were activated to monitor the temperature at 1710cm² in real time. -1 Absorbance of characteristic peaks of ester groups.

[0053] 2. Constant temperature and low-intensity oscillation: After heating to 460℃, a mixed atmosphere of 60% nitrogen and 40% oxygen was introduced at a flow rate of 0.45L / min, and the temperature was kept constant for 13 hours; during the last 1.8 hours of constant temperature, low-intensity oscillation was started with a frequency of 95Hz and an amplitude of 4.5mm.

[0054] 3. Cooling treatment: After the constant temperature period, a controllable cooling rate of 8℃ / min is adopted to ensure that the positive electrode material is cooled to room temperature.

[0055] 4. High-intensity oscillation and separation: After cooling, high-intensity oscillation is started with an initial frequency of 195Hz and an amplitude of 11mm; according to the sensor linkage: when the absorbance is >0.6, the parameters are maintained; when it drops to 0.2-0.6, the frequency is adjusted to 120Hz and the amplitude to 8mm; when it is <0.2, the oscillation is stopped; the powder is separated from the aluminum foil by sieving through a 100-mesh sieve to obtain positive electrode powder with the binder completely degraded.

[0056] Comparative Example 1 (High-intensity oscillation only after cooling) 1. Heating treatment: Place the positive electrode material in a muffle furnace and heat it to 500°C at a rate of 10°C / min. The air flow rate is 3L / min. Do not start the electrostatic adsorption plate and the near-infrared sensor. 2. Constant temperature treatment: After heating to 500℃, air is introduced at a flow rate of 0.3L / min, and the temperature is kept constant for 10 hours without low-intensity vibration; 3. Cooling process: Allow to cool naturally to room temperature; 4. Oscillation separation: After cooling, start high-intensity oscillation (frequency 180Hz, amplitude 10mm) directly, continue for 30 minutes and then stop, sieve with a 100-mesh screen, without near-infrared parameter control.

[0057] Comparative Example 2 (low-intensity oscillation only during the heating phase, no oscillation after cooling) 1. Heating treatment: The positive electrode material is placed in a tube furnace and heated to 450°C at a rate of 10°C / min, with an air flow rate of 3L / min. The electrostatic adsorption plate and near-infrared sensor are not activated. 2. Temperature control and oscillation: After heating to 450℃, a 50% oxygen-nitrogen mixture atmosphere was introduced at a flow rate of 0.2L / min. The temperature was controlled for 12 hours. In the last 2 hours, low-intensity oscillation (frequency 90Hz, amplitude 4mm) was started without parameter control. 3. Cooling process: Allow to cool naturally to room temperature; 4. Separation: After cooling, the material is directly sieved through a 100-mesh sieve without high-intensity shaking.

[0058] Experimental data:

[0059] Table 1 Comparison of Test Results Stripping efficiency: The mass analysis method is adopted, and the formula is "(mass of effective positive electrode powder after stripping ÷ total mass of initial positive electrode powder) × 100%", which is calculated by weighing the mass difference before and after using a precision electronic balance (accuracy 0.1mg).

[0060] Particle breakage rate: The particle size distribution of the cathode powder was determined using a laser particle size analyzer, and the percentage of broken particles with a particle size <1μm was calculated to account for the total particle mass.

[0061] As shown in Table 1 above, the stripping efficiency of this method is 88%-91%, while the stripping efficiency of the comparative method using only a single oscillation is 72%-79%, indicating that this method has a higher stripping efficiency. Furthermore, the particle breakage rate of this method (1.8%-2.5%) is also significantly lower than that of the comparative method (6.7%-8.3%). Therefore, the lithium-ion battery cathode material pretreatment method of this patent can achieve efficient and complete stripping of the cathode material from the current collector.

[0062] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0063] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0064] The above provides a detailed description of a lithium-ion battery cathode material pretreatment method. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and its core ideas. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for pretreating lithium-ion battery cathode materials, used to recycle waste lithium battery cathode materials, wherein the powder on the surface of the cathode material is bonded to a current collector by a binder, characterized in that... Including the following steps: The positive electrode material is heated to the target temperature according to the set heating program; At the target temperature, the positive electrode material is subjected to heat preservation treatment in a preset atmosphere through dynamic airflow control, and a first intensity oscillation is performed during the heat preservation treatment process; After cooling to room temperature, the positive electrode material is subjected to a second intensity of oscillation to cause the powder on the surface of the positive electrode material to peel off from the current collector; wherein the oscillation frequency and amplitude of the second intensity oscillation are both higher than those of the first intensity oscillation.

2. The method according to claim 1, characterized in that, The set heating program is a uniform heating rate, with an initial temperature of 25±5℃, a heating rate of 5℃-20℃ / min, and a target temperature of 300-600℃.

3. The method according to claim 1, characterized in that, The set heating program is a gradient heating, heating at a rate of 5-20℃ / min to 100-200℃ and holding for 2-4 hours; then heating to 200-300℃ and holding for 3-6 hours; finally heating to 400-600℃ and holding for 4-8 hours.

4. The method according to claim 1, characterized in that, The heating device is a muffle furnace or a tube furnace.

5. The method according to claim 4, characterized in that, The heating device is equipped with an electrostatic adsorption plate, which is used to adsorb trace amounts of binder carbon powder remaining in the airflow during the heating and heat preservation process.

6. The method according to claim 1, characterized in that, The preset atmosphere is oxygen, or a mixture of oxygen, nitrogen and ozone.

7. The method according to claim 1, characterized in that, The dynamic airflow control uses a first flow rate for ventilation during the heating phase and a second flow rate for ventilation during the heat preservation phase; wherein the first flow rate is higher than the second flow rate.

8. The method according to claim 1, characterized in that, The heat preservation treatment time is 6-14 hours.

9. The method according to claim 8, characterized in that, The step of performing the first intensity vibration during the heat preservation process includes: During the last 1-2 hours of the heat preservation process, a first-intensity vibration treatment is carried out simultaneously. The vibration frequency of the first-intensity vibration is 50-100Hz, and the amplitude is 2-5mm.

10. The method according to claim 1, characterized in that, The second intensity oscillation has an oscillation frequency of 150-200Hz and an amplitude of 8-12mm.

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