Method and device for stripping and recovering active materials of waste battery

Abstract

A method for stripping electrode sheets from a waste battery. The method comprises: stripping a mixed system comprising electrode sheets of a waste battery and a water-containing solvent under the assistance of ultrasound and ozone, and separating current collectors and electrode active materials from the electrode sheets. The present invention further comprises a solution of deeply removing impurities from the stripped electrode materials. A positive electrode active material of the battery is subjected to alkali leaching for aluminum removal, shearing ozone-assisted fluorine removal and the degradation of a residual electrolyte solution to obtain a high-purity positive electrode active material. The purposes of the deep removal of copper and the removal of residual organic electrolytes from a negative electrode active material can be achieved by means of acid leaching for copper removal and ozone oxidation. By adding a fluorine removal agent to a fluorine-containing and lithium-containing solution generated in the process of shearing fluorine removal, fluorine ions are converted into a stable precipitate, and therefore the generation of a harmful fluorine-containing gas is effectively prevented; and slightly-soluble LiF is converted into a lithium salt solution with a relatively high solubility, and then an Li2CO3 product is obtained by means of subsequent carbonization and decarburization reactions. The present invention further relates to a device capable of achieving the above-mentioned purposes.

Description

Method and device for stripping and recycling active materials from waste batteries Technical Field

[0001] The present invention belongs to the field of waste battery recycling, and in particular relates to the field of battery active material stripping and recycling. Background Art

[0002] With the gradual depletion of traditional mineral energy and increasing environmental protection requirements worldwide, clean lithium-ion energy is attracting significant attention. Statistics indicate that my country's lithium-ion battery shipments reached 655 GWh in 2022, a 100% year-on-year increase. Furthermore, China accounts for 69% of global lithium-ion battery shipments, making it a leading producer and user of lithium-ion batteries. Against this backdrop, the number of used lithium-ion batteries in my country is increasing, leading to a rapidly growing demand for battery recycling.

[0003] The stripping of battery active materials is a technical bottleneck and a critical step in the recycling of spent lithium-ion batteries. Generally speaking, the bonding force between the negative electrode material and the current collector gradually weakens with age, allowing subsequent separation through simple mechanical forces. However, the positive electrode material is tightly bonded to the aluminum foil using binders such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTEF), making it difficult to achieve effective separation using simple physical means.

[0004] Currently, the main techniques for separating electrode materials include solvent dissolution, heat treatment, and mechanical-physical methods. Solvent dissolution methods include organic solvent immersion and alkaline leaching. The organic solvent method, based on the principle of "like dissolves like," uses organic solvents such as N-methylpyrrolidone (NMP), dimethylformamide (DMF), and ethanol to dissolve the binder, thereby removing the active material. The alkaline leaching method uses an alkaline solution to dissolve the current collector (aluminum foil) to produce an aluminum-containing solution and active material. Solvent dissolution methods can effectively avoid toxic fume emissions, but organic solvents are relatively expensive and toxic, posing a significant health hazard to operators. Although alkaline solutions are less toxic, they produce large amounts of aluminum-containing solution, hindering subsequent impurity removal. Heat treatment, with its low cost and simple operation, is currently one of the most widely used techniques in the industry. This method uses high temperatures to decompose the binder in the electrode material, thereby removing the active material. However, the pyrolysis of organic materials such as PVDF produces large amounts of toxic gases, and the environmental pollution potential requires further evaluation and investigation. Furthermore, the pyrolysis of the binder (PVDF) and electrolyte (LiPF6) produces a large amount of F-containing gas, which not only pollutes the environment and corrodes equipment but also reacts with aluminum foil and LiFePO4 to form AlF3, LiAlPO4, and AlPO4. AlF3 is a very stable precipitate, insoluble in acids and alkalis and possessing excellent thermal stability. Therefore, once formed, it is difficult to effectively remove. Furthermore, the valence of Al is relatively stable, and the formation of LiAlPO4 and AlPO4 can significantly degrade the performance of the resulting lithium-ion battery after repair. The mechanical-physical method involves mechanically crushing the components of spent lithium-ion batteries to initially separate them. Ball milling, screening, and flotation are then used to obtain relatively pure electrode active materials. This method offers the advantages of simplicity and ease of industrialization, but the resulting electrode products contain high copper and aluminum content, making subsequent impurity removal challenging. Furthermore, this method does not effectively dispose of organic matter, requiring further treatment. Technical issues

[0005] In summary, current technologies for separating active materials from spent lithium-ion batteries suffer from high production costs, severe environmental pollution, and low product performance, creating a bottleneck that hinders the green and efficient recycling of spent lithium-ion batteries. There is an urgent need for a green, environmentally friendly, and efficient active material separation technology and device to achieve efficient, clean pretreatment of active materials from spent lithium-ion batteries. Technical Solutions

[0006] In response to the problems of low efficiency, high cost and difficult control of the quality of the stripped products in the existing electrode sheet stripping, the first purpose of the present invention is to provide a method for stripping the electrode sheets of waste batteries, aiming to achieve in-situ non-destructive stripping of the active materials of waste batteries, improve the stripping efficiency and reduce the processing cost.

[0007] The second purpose of the present invention is to provide a method for recycling and purifying electrode materials of old battery electrode plates, aiming to obtain high-purity electrode materials with low current collector, low fluorine and low organic residue from the electrode plates.

[0008] The present invention also includes equipment capable of stripping and recycling the waste battery electrode sheets.

[0009] A method for stripping waste battery electrode sheets comprises stripping a mixed system comprising waste battery electrode sheets and an aqueous solvent under the assistance of ultrasound and ozone to separate the current collector and electrode material in the electrode sheets.

[0010] The present invention's innovative research demonstrates that the ultrasound-ozone-assisted stripping process can rapidly separate battery active materials from the current collector at room temperature while maintaining the integrity of the current collector. The resulting active material maintains a stable chemical structure, greatly facilitating subsequent recycling or repair. Furthermore, during the stripping process, only trace amounts of current collector debris are mixed into the active material, allowing for subsequent thorough removal of impurities through simple acid-base treatment.

[0011] The stripping process described in this invention has excellent universality, particularly for electrode plates containing hydrophobic binders such as PVDF, achieving excellent stripping efficiency and effectiveness in aqueous systems. Furthermore, the method eliminates the need for plate fragmentation, simplifying the process and enabling better current collector recycling.

[0012] In the present invention, the waste battery electrode plates are electrode plates obtained by disassembling and separating waste lithium-ion batteries.

[0013] In the present invention, there is no special requirement for the type of waste lithium-ion batteries.

[0014] In the present invention, the electrode plates include positive plates and / or negative plates.

[0015] In the present invention, the positive electrode sheet may include a positive electrode current collector (such as Al foil) and a positive electrode material composited on its surface, wherein the positive electrode material includes a positive electrode active material, a binder and a conductive agent. There are no special requirements for the positive electrode active material, for example, 、 In at least one of the above, the M may be Fe or Mn, and the N may be at least one of Ni, Mn, and Co. The binder may be a water-soluble or water-insoluble binder, for example, PVDF.

[0016] In the present invention, the negative electrode sheet comprises a negative electrode current collector (e.g., Cu foil) and a negative electrode material composited on its surface. The negative electrode material comprises a negative electrode active material, a binder, and a conductive agent. The negative electrode active material, for example, comprises at least one of a carbon-based active material, a silicon-based active material, and a silicon-carbon composite material. The carbon-based active material may be, for example, graphite. The binder may be water-soluble or water-insoluble, such as CMC.

[0017] In the present invention, the electrode plates may be pre-cut as needed before being peeled off.

[0018] In the present invention, the positive electrode sheet and the negative electrode sheet in the electrode sheet can be peeled off separately or together.

[0019] In the present invention, the aqueous solvent is water or a mixed solvent of water and an organic solvent; the organic solvent is a solvent that is miscible with water and cannot be decomposed by ozone.

[0020] In the present invention, the liquid-to-solid ratio of the electrode plate to the aqueous solvent can be controlled as needed, and can be further adjusted to 1-10 mL / g in consideration of processing costs.

[0021] In the present invention, an ozone-containing atmosphere is introduced into the mixed system, and the stripping is performed under the assistance of ultrasound;

[0022] In the present invention, the ultrasonic and ozone-assisted gas-solid-liquid three-phase reaction treatment helps to significantly improve the stripping efficiency and effect.

[0023] Preferably, the concentration of ozone in the ozone-containing atmosphere is above 1 vol.%;

[0024] In the present invention, the amount of ozone introduced can be adjusted according to needs, production scale, and efficiency. Considering the processing cost, it can be 0.5-10 times the theoretical amount, and more preferably 3-10 times. The theoretical amount is the theoretical amount of ozone required to oxidize the binder in the electrode sheet.

[0025] The optional inlet flow rate can be above 10 mL / min, further above 100 mL / min, and furthermore can be 100-100000 mL / min.

[0026] Preferably, the ultrasonic power is 50 to 500 W, more preferably 80 to 200 W. In the present invention, under the above-mentioned excess power, the ultrasonic-ozone synergistic effect can be further improved, which helps to further synergistically improve the stripping efficiency and effect.

[0027] In the present invention, the temperature during the stripping process is above 0°C, for example, 0-100°C, and can be further 15-40°C considering the convenience of process operation;

[0028] In the present invention, there is no special requirement for the stripping time, and the stripping process takes more than 5 minutes. However, considering the excellent synergistic stripping efficiency of the process of the present invention, the efficiency of the technology can be achieved, and the stripping time can be controlled within 10 to 90 minutes.

[0029] In the present invention, the stripping method can be implemented based on existing equipment equipped with ultrasound.

[0030] The present invention also provides a method for recycling and purifying electrode materials of waste battery electrode plates, wherein a crude electrode material is obtained by the stripping method of the present invention, the crude electrode material is subjected to a deep current collector removal treatment to obtain a first-stage treated material, and the first-stage treated material is slurried and subjected to a shear ozone-assisted defluorination treatment to obtain a purified electrode material.

[0031] In the present invention, the electrode material crude product obtained by stripping can be subjected to deep current collector removal treatment based on known processes. For example, the deep current collector removal treatment is carried out by acid treatment or alkali treatment;

[0032] In the present invention, when the electrode material comprises a positive electrode material, the deep current collector removal treatment method is an alkali treatment. The operation steps include, for example, placing the crude positive electrode material obtained by stripping in an alkali solution for alkali treatment, followed by solid-liquid separation to obtain a treated material. The alkali solution is, for example, an aqueous solution of an alkali metal hydroxide.

[0033] In the present invention, when the electrode material comprises a negative electrode material, the method for deep current collector removal is acid treatment. The process steps include, for example, placing the crude negative electrode material obtained by stripping in an acid solution for acid treatment, followed by solid-liquid separation to obtain a treated material. The acid solution may be, for example, an aqueous solution of at least one of hydrochloric acid, sulfuric acid, and nitric acid.

[0034] In the present invention, the crude electrode material is subjected to a deep defluorination treatment in advance, and then defluorination is carried out in combination with a shear ozone method. The shearing method can achieve sufficient mass transfer and reaction of the three-phase reaction of gas (ozone), liquid (solution phase), and solid (organic matter), thereby improving the deep defluorination effect and helping to obtain high-quality electrode materials.

[0035] In the present invention, the solvent in the first stage slurrying process is an aqueous solvent. Considering the composition of the process and the reduction of three wastes, it can be the mother liquor of solid-liquid separation after stripping;

[0036] In the present invention, the content of the first-stage treated material in the slurry obtained by slurrying the first-stage treated material can be adjusted as needed, for example, it can be 3-5 g / mL.

[0037] In the present invention, a shear ozone-assisted defluorination treatment is innovatively performed on a first stage of treated material, thereby achieving a deep defluorination effect.

[0038] In the present invention, the shear ozone assisted treatment refers to a treatment process in which a slurry containing a first stage of treatment material and ozone are mixed and reacted by a shear mixing device. The shear mixing device can be a device known in the industry that can achieve shear mixing function by shearing.

[0039] In the present invention, during the shear ozone-assisted defluorination treatment process, the reaction system (slurry) can be circulated and input into the shear mixing device and ozone shear mixing for circulatory treatment.

[0040] In the present invention, during the circulation treatment stage, the slurry circulation input is located near the slurry surface. The slurry circulation output is located above and / or below the slurry surface (preferably at the bottom of the slurry). The circulation method described in the present invention can be understood as a top-input circulation method.

[0041] In the present invention, the input end is kept as close to the slurry surface as possible while ensuring slurry circulation. Preferably, the distance between the input end and the liquid surface is within 5 cm, more preferably within 2 cm. Research has shown that this circulation treatment method can further improve process synergy and contribute to improved deep fluoride removal.

[0042] In the present invention, the bottom of the slurry may specifically be a region that is more than 10 cm away from the liquid surface.

[0043] In the present invention, the slurry is circulated and further combined with the above-mentioned top-in circulation method, so that a deep defluorination effect can be achieved.

[0044] In the present invention, the ozone injection rate during the shear ozone-assisted defluorination treatment stage is 1 to 10 times, and more preferably 2 to 5 times, the theoretical amount required to completely convert the organic fluorine-containing components in the system into inorganic fluorine. The flow rate can be adjusted as needed, for example, to above 10 mL / min, further to above 100 mL / min, and even further to 100 to 100,000 mL / min.

[0045] Preferably, the shear rate in the shear ozone-assisted defluorination treatment stage is 1000-6000 r / min;

[0046] Preferably, the reaction temperature in the shear ozone-assisted defluorination treatment stage is 20-60°C;

[0047] Preferably, the reaction time of the shear ozone-assisted defluorination treatment stage is greater than 30 min;

[0048] Preferably, after the shear ozone-assisted defluorination treatment is completed, solid-liquid separation is performed to obtain purified electrode materials and fluorine-containing and lithium-containing waste liquids respectively; the above-mentioned fluorine-containing and lithium-containing waste liquids are defluorinated by a defluoridating agent to obtain fluoride precipitates and lithium-containing solutions respectively.

[0049] In the present invention, the stripping process can be achieved based on conventional equipment with ultrasonic function, and the shear ozone treatment process can also be achieved based on conventional shear gas-liquid mixing equipment.

[0050] In the present invention, in order to make the technical solution more industrially applicable, the present invention also designs a set of highly integrated waste battery electrode sheet stripping and recycling purification devices that are conducive to industrial application and can implement the recycling and purification method, including a box body, the box body is provided with a feed port, a discharge port (10) and a reaction zone, a discharge bin (2) and a discharge motor (1) are provided at the feed port, a current collector unloading belt (11) is provided at the discharge port, and a conveying mechanism is provided in the box body that passes through the feed port, the reaction zone and the discharge port in sequence;

[0051] The reaction zone contains a liquid phase reaction system. An active material discharge port (13) is provided at the bottom of the reaction zone. An active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13). A conveying mechanism passes through the liquid phase reaction system in the reaction zone. The reaction zone is also connected to a forced circulation pump (3), a gas-liquid shear mixing device, and an ultrasonic generator (15).

[0052] The gas-liquid shear mixing device comprises a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulation input pipeline connected to the solution inlet, and a circulation output pipeline (gas-liquid mixing pipeline 6) connected to the solution outlet, wherein the input end (19) of the circulation input pipeline is arranged at or below the liquid level of the liquid phase reaction system in the reaction zone; the nozzle (7) of the circulation output pipeline is arranged at the top, bottom or side of the reaction zone;

[0053] The transmission mechanism includes a transmission chain (9), a chain guide wheel (16), a charging bin (8), a chain transmission motor (17) and a driving wheel (18); a plurality of chain guide wheels (16) are fixedly connected to the box body; the transmission chain (9) is sleeved on each chain guide wheel (16) in a closed loop; a charging bin (8) is provided on each segment of the transmission chain (9); and the transmission chain (9) is driven by the chain transmission motor (17) and the driving wheel (18).

[0054] The device described in the present invention deeply couples ultrasound, ozone oxidation and shearing processes, and can achieve in-situ non-destructive stripping of positive and negative electrode active materials and deep removal of residual current collectors, organic matter and organic fluorine.

[0055] The device of the present invention mainly comprises a loading device (1, 2), a unloading device (10, 11; 12, 13, 14), an ultrasonic device (15), a chain transmission device (16, 17, 18) and a shearing device (5). During operation, the battery electrode pieces enter the loading bin (8) through the unloading bin (2) and enter the reaction area along with the chain transmission (9). During the reaction, the ultrasonic device (15) and the shearing device (5) are simultaneously turned on and ozone is continuously introduced. During the reaction, ozone enters the high-speed rotating part of the shearing machine together with the slurry circulated from the input end through the ozone inlet (4), thereby achieving a full mixing of the gas, liquid and solid three phases. Afterwards, the evenly mixed gas, liquid and solid three phases are sprayed into the reaction chamber through the mixture nozzle (7) to flush the battery pieces and further accelerate the shedding of the active material. After the reaction is completed, the current collector and the active material are discharged through the current collector outlet (10) and the active material discharge port (13) respectively.

[0056] In the present invention, the input end (19) is as close to the slurry liquid surface as possible while ensuring the early stage of slurry input. Preferably, the input end is inserted into the liquid surface of the reaction solution system, and the distance from the lower surface of the liquid surface is controlled to be less than 5 cm, preferably less than 2 cm. Beneficial effects

[0057] This invention innovatively utilizes an ultrasound-ozone-assisted stripping process to achieve non-destructive, in-situ stripping of battery active materials. The reaction process does not involve expensive, toxic reagents, resulting in excellent economic and technical performance. Unlike traditional pyrolysis processes, this reaction can be carried out at room temperature and does not produce harmful fluorine-containing gases. Furthermore, the chemical properties of the copper and aluminum foils remain virtually unchanged during the reaction, allowing subsequent deep removal of copper and aluminum through simple acid or alkaline leaching. This is highly beneficial for the extraction of valuable elements from battery materials or the direct repair of battery materials.

[0058] In the present invention, the electrode material obtained by stripping is subjected to residual current collector removal and subsequent shear ozone defluorination treatment to obtain pure electrode active material. The introduction of shear can greatly improve the defluorination effect. Further combined with the control of the circulation mode of the shear ozone treatment stage, the purpose of deep defluorination and degradation of organic matter can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1: Process flow chart of the present invention.

[0060] Figure 2 is a schematic diagram of the circulation process, wherein the left figure is a schematic diagram of the bottom-entry circulation method; the right figure is a schematic diagram of the top-entry circulation method;

[0061] Figure 3: Schematic diagram of the device for ultrasound-assisted ozone high-efficiency stripping of battery active materials according to the present invention.

[0062] 1. Discharge motor; 2. Discharge silo; 3. Forced circulation pump; 4. Ozone inlet; 5. Shear mixing device; 6. Gas-liquid mixing pipeline; 7. Gas-liquid mixture nozzle; 8. Loading silo; 9. Drive chain; 10. Collector (copper or aluminum foil) outlet; 11. Collector discharge belt; 12. Active material discharge pump; 13. Active material discharge port; 14. Active material discharge valve; 15. Ultrasonic generator; 16. Chain guide pulley; 17. Chain drive motor; 18. Drive pulley. 19. Input end of the circulation input pipeline.

[0063] The process principle of the present invention is described in detail as follows:

[0064] (1) Decomposition and removal of organic matter

[0065] The organic matter in waste lithium-ion batteries mainly includes electrolyte and binder. The degradation reaction of PVDF is as follows:

[0066] ;

[0067] In addition, ozone can also produce a certain amount of hydroxyl radicals (·OH) in the aqueous solution system, which can further react with organic matter such as PVDF. Taking PVDF as an example:

[0068] ;

[0069] The main components of the electrolyte are ethylene carbonate (EC), ethyl methyl carbonate (EMC), propylene carbonate (PC) and diethyl carbonate (DEC). All of the above substances are hydrocarbons, which will decompose into CO2 and H2O under the action of ozone.

[0070] (2) Deep removal of copper and aluminum

[0071] Cu(s)+H2SO4(aq)=CuSO4(aq)+H2(g)

[0072] Al(s)+NaOH(aq)+H2O(l)=NaAlO2(aq)+1.5H2(g)

[0073] (3) Lithium extraction and fluorine removal (using CaO as a defluorination agent)

[0074] LiF(aq,s)+CaO(s)+H2O(l)=CaF2(s)↓+LiOH(aq)

[0075] HF(aq)+CaO(s)=CaF2(s)↓+H2O(l). Modes for Carrying Out the Invention

[0076] The recycling process of the present invention may include the following steps:

[0077] (1) Discharge

[0078] Place the used lithium-ion batteries in a saturated sodium chloride or sodium sulfate solution and discharge them completely for later use.

[0079] (2) Battery disassembly

[0080] The waste batteries described in step (1) are manually or mechanically dismantled and separated to obtain negative and positive electrode plates.

[0081] (3) Ultrasonic-assisted ozone stripping of electrode active materials

[0082] The battery electrodes described in step (2) are placed in an ultrasonic tank filled with water. The ultrasonic equipment is turned on and a certain flow of ozone gas is introduced for a certain reaction time to obtain a current collector (copper foil or aluminum foil), a battery active material (positive electrode active material or negative electrode active material), and a positive electrode active material ultrasonic post-solution liquid A and a negative electrode active material ultrasonic post-solution liquid B.

[0083] (4) Deep removal of copper and aluminum

[0084] The positive electrode active material is further subjected to alkaline leaching to deeply remove residual aluminum foil debris; the negative electrode active material can be acid leached under certain conditions to achieve the purpose of deeply removing copper.

[0085] (5) Fluorine removal and degradation of residual electrolyte under shear-assisted ozone conditions

[0086] The positive electrode active material and ultrasonic liquid A after impurity removal in step (4) and the negative electrode active material and ultrasonic liquid B are placed in a shear enhancement reaction device respectively and ozone is continuously introduced for a certain period of time. During the shear reaction of the positive electrode active material, the material circulation method adopts the upper in and lower out method.

[0087] (6) Extraction of Li from solution system and opening of fluorine circuit

[0088] The solution obtained in step (5) is recycled until Li + 、F - After the solution is enriched to a certain extent, a certain amount of defluoridating agent is added to the solution to remove the F in the solution. - It is converted into a more stable fluoride precipitate and simultaneously produces a more soluble lithium salt.

[0089] The ozone concentration in step (3) is 1-100 vol.%, and the ozone introduction time is 15-90 min.

[0090] The volume ratio of the battery electrode to the aqueous phase in step (3) is 1:10 to 1:1.

[0091] The operating temperature in step (3) is 0-100°C, more preferably 15-40°C.

[0092] The ultrasonic power described in step (3) is 50~500W.

[0093] The material circulation mode of the shearing process in step (5) is top-in and bottom-out, and the shearing rate is 1000-6000 r / min.

[0094] The reaction temperature of the shearing process in step (5) is 20-60°C, the reaction liquid-solid ratio is 3-5, and the reaction time is >30 min.

[0095] The following examples illustrate the essence of the present invention, but the protection scope of the present invention is not limited thereto.

[0096] In the following cases, the unit of liquid-to-solid ratio is mL / g;

[0097] In the following cases, the current collectors and binders used in the batteries can be conventional in the industry. For example, the positive electrode current collector can be Al foil, and the binder can be PVDF. The negative electrode current collector can be Cu foil, and the binder can be an oil-based or water-based binder, such as CMC. The following are specific examples:

[0098] Example 1 (FeP positive electrode stripping)

[0099] Step 1: Disassemble the used lithium iron phosphate battery to obtain the positive and negative electrodes. Cut the resulting positive electrode into small pieces approximately 2 cm in length and place them in a water-filled ultrasonic bath (a conventional ultrasonic bath can be used). Then, turn on the ultrasonic equipment (100 W) and introduce 500 mL / min of ozone at room temperature for 30 minutes to produce aluminum foil, positive electrode active material, and post-ultrasonication liquid.

[0100] Step 2: Place the positive electrode active material after ultrasonic stripping in a liquid alkali reaction tank and react for 30 minutes at a temperature of 40°C and a liquid-solid ratio of 4:1 to obtain a positive electrode active material after deep dealuminization.

[0101] Step 3: The cathode active material after deep aluminum removal in Step 2 is mixed with the post-ultrasonication solution obtained in Step 1 in a container to form a mixed solution. A top-input circulation system is used (see Figure 2, right, for a schematic diagram, with the circulation inlet positioned at a distance of 2 cm or less from the mixed solution surface). The mixed solution is shear-mixed with ozone in a shear mixing device (in this case, a FULAI FL40Z) and circulated to the bottom of the mixed solution (at least 10 cm from the liquid surface) for 30 minutes. Ozone is continuously introduced at 500 mL / min during the reaction. The temperature during the cyclic reaction stage is 40°C, the reaction liquid-to-solid ratio is 3:1, and the shear speed is 3000 rpm. After the reaction, pure battery active material and leachate are obtained.

[0102] After chemical detection and calculation, the Li content in the raw material is 5.45%, the F content is 2.64%, the organic carbon content is 2.82%, and the physical phase of the positive electrode material is LiFePO4. After step one treatment, the stripping rate of the positive electrode active material is 99.01%, and the Al content in the obtained positive electrode material is 0.29%, the F content is 2.54%, the Li content is 4.25%, and the organic carbon content is 2.14%. After step two treatment, the Al content is reduced to 0.0085%, and the contents of other components remain basically unchanged. After step three treatment, the F content in the positive electrode material is reduced to 0.014%, the Li content is reduced to 3.45%, and the organic carbon content is reduced to 0.021%. The main physical phase of the positive electrode active material after deep impurity removal is .

[0103] Example 2 (Ternary Positive Electrode Stripping)

[0104] Step 1: Disassemble the used ternary lithium-ion batteries to obtain the positive and negative electrodes. Cut the resulting positive electrode sheets into small pieces approximately 2 cm in length and place them in a water-filled ultrasonic bath. Then, turn on the ultrasonic equipment (100 W) and introduce ozone at 500 mL / min for 30 minutes to produce aluminum foil, positive electrode active material, and post-ultrasonication liquid.

[0105] Step 2: Place the positive electrode active material after ultrasonic stripping in a liquid alkali reaction tank and react for 30 minutes at a temperature of 40°C and a liquid-solid ratio of 4:1 to obtain a battery active material after deep aluminum removal.

[0106] Step 3: The cathode active material after deep aluminum removal in Step 2 is mixed with the post-ultrasonication solution obtained in Step 1 in a container to form a mixed solution. A top-input circulation system is used (see Figure 2, right, for a schematic diagram, with the circulation inlet positioned at a distance of 2 cm or less from the mixed solution surface). The mixed solution is shear-mixed with ozone in a shear mixing device (in this case, a FULAI FL40Z) and circulated to the bottom of the mixed solution (at least 10 cm from the liquid surface) for 90 minutes. Ozone is continuously introduced at 500 mL / min during the reaction. The temperature during the cyclic reaction phase is 25°C, the liquid-to-solid ratio is 3:1, and the shear speed is 3500 rpm. After the reaction, pure battery active material and leachate are obtained.

[0107] After chemical testing and calculation, the Li content in the raw material was 4.58%, the F content was 3.01%, and the organic carbon content was 2.08%. After step one treatment, the stripping rate of the positive electrode active material was 99.21%. The Al content in the obtained positive electrode material was 0.19%, the F content was 2.57%, the Li content was 3.98%, and the organic carbon content was 1.75%. After step two treatment, the Al content was reduced to 0.0094%, and the contents of the other components remained basically unchanged. After step three treatment, the F content in the positive electrode active material was reduced to 0.014%, the Li content was reduced to 3.45%, and the organic carbon content was reduced to 0.015%. The leaching rates of Ni, Co, and Mn in the entire process were all lower than 2.5%.

[0108] Example 3 (Negative Electrode Stripping)

[0109] Step 1: Disassemble the used lithium iron phosphate batteries to obtain the positive and negative electrode sheets (active ingredient: graphite). Cut the negative electrode sheet into small pieces approximately 2 cm in length and place them in an ultrasonic bath filled with water. Then, operate the ultrasonic device (80 W) at room temperature for 20 minutes to produce copper foil, negative electrode active material, and post-ultrasonication solution.

[0110] Step 2: Place the negative electrode active material after ultrasonic stripping in a dilute sulfuric acid reaction tank and react for 30 minutes at a temperature of 40°C and a liquid-to-solid ratio of 4:1 to obtain a battery active material after deep copper removal.

[0111] Step 3: The cathode active material after deep aluminum removal in Step 2 is mixed with the post-ultrasonication solution obtained in Step 1 in a container to form a mixed solution. A top-input circulation system is used (see Figure 2, right, for a schematic diagram, with the circulation inlet positioned at a distance of less than or equal to 2 cm from the mixed solution surface). The circulating mixed solution is shear-mixed with ozone in a shear mixing device (in this case, a FULAI FL40Z) and circulated to the bottom of the mixed solution (at a distance of more than 10 cm from the liquid surface). The circulating reaction is continued for 90 minutes, with ozone continuously introduced at a rate of 500 mL / min. The temperature during the cyclic reaction phase is 25°C, the reaction liquid-to-solid ratio is 3:1, and the shear speed is 3000 rpm. After the reaction, pure anode active material and leachate are obtained.

[0112] Chemical testing and calculations revealed an organic carbon content of 1.02% in the raw material. After step one, the stripping rate of the negative electrode active material was 99.25%. The resulting positive electrode material contained 0.19% Cu and 0.87% organic carbon. After step two, the Cu content was reduced to 0.0024%. After step three, the residual organic carbon content in the negative electrode active material was 0.047%.

[0113] Example 4 (Fluorine precipitation and lithium extraction)

[0114] The leachates obtained in step 3 of Example 1 and Example 2 were mixed evenly, and 1.3 times the theoretical amount of CaO for fluorine precipitation was added thereto. The mixture was reacted at 60°C for 75 minutes and then filtered to obtain a Li-containing solution and a CaF2 precipitate, respectively. Subsequently, CO2 was continuously introduced into the above-mentioned Li-containing solution at room temperature for 30 minutes to obtain a LiHCO3 solution. The LiHCO3 solution was decarbonized at 90°C for 60 minutes, filtered, washed, and dried to obtain Li2CO3. Calculations showed that the precipitation rate of F was 96.24%, and the direct yield and purity of lithium carbonate were 84.57% and 99.81%, respectively.

[0115] Example 5

[0116] Compared with Example 1, the only difference is that the ultrasonic power during the stripping process of the positive electrode active material in step 1 is 300 W.

[0117] After chemical testing and calculation, the stripping rate of the positive electrode active material obtained by step one treatment is 98.12%. The positive electrode sheet has obvious perforation phenomenon. The Al content in the obtained positive electrode material is 2.13%, the F content is 2.05%, the Li content is 5.38%, and the organic carbon content is reduced to 1.95%. After step two treatment, the Al content is reduced to 0.012%, and the contents of other components remain basically unchanged. After step three treatment, the F content is reduced to 0.015%, the Li content is reduced to 3.55%, and the organic carbon content is reduced to 0.019%. The main phases of the battery positive electrode active material after the above steps are .

[0118] Example 6

[0119] Compared with Example 1, the only difference is that in step 3, the circulation mode is changed to the bottom-in mode, specifically, the input end of Example 1 is set to the output end, and the output end is set to the input end (see the left figure of Figure 2 for an example of the circulation mode).

[0120] After chemical testing and calculation, the stripping rate of the positive electrode active material obtained by step one is 99.01%. The Al content in the obtained positive electrode material is 0.29%, the F content is 2.54%, the Li content is 4.25%, and the organic carbon content is reduced to 2.68%. After step two treatment, the Al content is reduced to 0.0078%, and the contents of other components remain basically unchanged. After step three treatment, the F content is 0.12%, the Li content is reduced to 3.33%, and the organic carbon content is reduced to 0.11%. The main phases of the battery positive electrode active material after the above steps are .

[0121] Comparative Example 1 (ultrasound alone)

[0122] Compared with Example 1, the only difference is that in step 1, ozone is not introduced during the stripping process of the positive electrode active material.

[0123] After chemical testing and calculation, the stripping rate of the positive electrode active material obtained by step one is 30.12%. The Al content in the obtained positive electrode material is 0.27%, the F content is 2.55%, the Li content is 5.01%, and the organic carbon content is 2.64%. After step two, the Al content is reduced to 0.0072%, and the contents of other components remain basically unchanged. After step three, the F content is reduced to 0.013%, the Li content is reduced to 3.52%, and the organic carbon content is reduced to 0.09%. The main phases of the battery positive electrode active material after the above steps are .

[0124] Comparative Example 2 (Ozone alone)

[0125] Compared with Example 1, the only difference is that in step 1, the ultrasonic equipment is not turned on during the stripping process of the positive electrode active material.

[0126] After chemical testing and calculation, the stripping rate of the positive electrode active material obtained by step one is 8.12%. The Al content in the obtained positive electrode material is 0.12%, the F content is 2.58%, the Li content is 5.38%, and the organic carbon content is reduced to 2.44%. After step two, the Al content is reduced to 0.0066%, and the contents of other components remain basically unchanged. After step three, the F content is reduced to 0.014%, the Li content is reduced to 3.64%, and the organic carbon content is reduced to 0.07%. The main phases of the battery positive electrode active material after the above steps are .

[0127] Comparative Example 3

[0128] Compared with Example 1, the only difference is that the gas introduced during the stripping process of the positive electrode active material in step 1 is air with the same flow rate.

[0129] After chemical testing and calculation, the stripping rate of the positive electrode active material obtained by step one is 5.12%. The Al content in the obtained positive electrode material is 0.13%, the F content is 2.38%, the Li content is 5.02%, and the organic carbon content is reduced to 2.38%. After step two, the Al content is reduced to 0.0058%, and the contents of other components remain basically unchanged. After step three, the F content is reduced to 0.014%, the Li content is reduced to 3.64%, and the organic carbon content is reduced to 0.07%. The main phases of the battery positive electrode active material after the above steps are .

[0130] Comparative Example 4

[0131] Compared with Example 1, the only difference is that the gas introduced during the shear reaction in step 3 is air with the same flow rate.

[0132] After chemical testing and calculation, the stripping rate of the positive electrode active material after step one treatment is 99.21%, the Al content in the obtained positive electrode material is 0.19%, the F content is 2.58%, the Li content is 4.33%, and the organic carbon content is 2.34%. After step two treatment, the Al content is reduced to 0.0078%, and the contents of other components remain basically unchanged. After step three treatment, the F content in the positive electrode material is reduced to 2.25%, the Li content is reduced to 3.58%, and the organic carbon content is reduced to 1.98%. The main phase of the positive electrode active material after deep impurity removal is .

[0133] Comparative Example 5

[0134] Compared with Example 1, the only difference is that in step 3, a conventional circulation pump is used to replace the shear mixing equipment.

[0135] After chemical testing and calculation, the stripping rate of the positive electrode active material obtained by step one is 99.01%. The Al content in the obtained positive electrode material is 0.29%, the F content is 2.54%, the Li content is 4.25%, and the organic carbon content is reduced to 2.78%. After step two, the Al content is reduced to 0.0085%, and the contents of other components remain basically unchanged. After step three, the F content is 0.54%, the Li content is reduced to 3.45%, and the organic carbon content is reduced to 0.19%. The main phases of the battery positive electrode active material after the above steps are .

[0136] Second, the implementation scheme of the highly integrated device as shown in FIG3

[0137] As shown in FIG3 : the waste battery electrode sheet stripping and recycling purification device comprises a box body, the box body is provided with a feed port, a discharge port (10) and a reaction zone, a discharge bin (2) and a discharge motor (1) are provided at the feed port, a current collector unloading belt (11) is provided at the discharge port, and a conveying mechanism is provided in the box body that passes through the feed port, the reaction zone and the discharge port in sequence;

[0138] The reaction zone contains a liquid phase reaction system. An active material discharge port (13) is provided at the bottom of the reaction zone. An active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13). A conveying mechanism passes through the liquid phase reaction system in the reaction zone. The reaction zone is also connected to a forced circulation pump (3), a gas-liquid shear mixing device, and an ultrasonic generator (15).

[0139] The gas-liquid shear mixing device comprises a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulation input pipeline connected to the solution inlet, and a circulation output pipeline (gas-liquid mixing pipeline 6) connected to the solution outlet, wherein the input end (19) of the circulation input pipeline is arranged at or below the liquid level of the liquid phase reaction system in the reaction zone; the nozzle (7) of the circulation output pipeline is arranged at the top, bottom or side of the reaction zone;

[0140] The transmission mechanism includes a transmission chain (9), a chain guide wheel (16), a charging bin (8), a chain transmission motor (17) and a driving wheel (18); a plurality of chain guide wheels (16) are fixedly connected to the box body; the transmission chain (9) is sleeved on each chain guide wheel (16) in a closed loop; a charging bin (8) is provided on each segment of the transmission chain (9); and the transmission chain (9) is driven by the chain transmission motor (17) and the driving wheel (18).

[0141] During operation, the battery electrode pieces enter the loading hopper (8) through the unloading hopper (2) and enter the reaction area along the chain drive (9). During the reaction, the ultrasonic device (15) and the shearing device (5) are turned on at the same time and ozone is continuously introduced. During the reaction, ozone enters the high-speed rotating part of the shearing machine through the ozone inlet (4), thereby achieving full mixing of the gas, liquid and solid three phases. After that, the mixed gas, liquid and solid three phases are sprayed into the reaction chamber through the mixture nozzle (7) to flush the battery pieces and further accelerate the shedding of the active material. After the reaction is completed, the current collector and the active material are discharged through the current collector outlet (10) and the active material discharge port (13) respectively.

[0142] In the present invention, the input end (19) is as close to the slurry liquid surface as possible while ensuring the early stage of slurry input. Preferably, the input end is inserted into the liquid surface of the reaction solution system, and the distance from the lower surface of the liquid surface is controlled to be less than 5 cm, preferably less than 2 cm.

[0143] Example 7

[0144] Compared with Example 1, the difference is that in step 1, in the device of Figure 3, ultrasound is turned on and ozone is input through the ozone inlet to perform ultrasonic ozone treatment. Other conditions are the same as those in Example 1; wherein, the stripping time can be regulated by controlling the chain transmission speed.

[0145] In step 3, the cathode active material after deep aluminum removal in step 2 is mixed with the post-ultrasonication liquid obtained in step 1 and then treated using the equipment shown in Figure 2 (right), wherein the shear mixing equipment model is Chuangyue ONG-403-2. Other operations and parameters are the same as in Example 1.

[0146] After treatment, the stripping rate of the positive electrode active material is 99.08%. The Al content of the obtained positive electrode material is 0.23%, the F content is 0.54%, the Li content is 4.25%, and the organic carbon content is 1.05%. After step 2 treatment, the Al content is reduced to 0.0085%, and the contents of the other components remain basically unchanged. After step 3 treatment, the F content in the positive electrode material is reduced to 0.013%, the Li content is reduced to 3.58%, and the organic carbon content is reduced to 0.019%. The main phase of the positive electrode active material after deep impurity removal is .

Claims

1. A method for peeling off the electrode plate of a waste battery, characterized in that, A mixed system containing waste battery electrode sheets and an aqueous solvent is stripped under the assistance of ultrasound and ozone to separate the current collector and the electrode active material in the electrode sheets.

2. The stripping method of the waste battery electrode sheet according to claim 1, characterized in that, The waste battery electrode sheets are electrode sheets disassembled and separated from waste lithium-ion batteries; Preferably, the electrode sheets include positive electrode sheets and / or negative electrode sheets.

3. The stripping method of the waste battery electrode sheet according to claim 1, wherein The aqueous solvent is water or a mixed solvent of water and an organic solvent; the organic solvent is a solvent miscible with water and cannot be decomposed by ozone; Preferably, the liquid-solid ratio of the electrode sheets to the aqueous solvent is 1-10 mL / g.

4. The method for stripping the electrode sheet of a waste battery according to any one of claims 1 to 3, characterized in that, An ozone-containing atmosphere is introduced into the slurry, and stripping is carried out under the assistance of ultrasound; Preferably, the concentration of ozone in the ozone-containing atmosphere is above 1 vol.%; Preferably, the power of the ultrasound is 50-500 W; Preferably, the temperature during the stripping process is above 0 °C, preferably 0-100 °C, and more preferably 15-40 °C; Preferably, the time of the stripping process is above 5 min, preferably 10-90 min.

5. A method for recycling and purifying the electrode material of used battery electrode plates, characterized in that, The crude electrode material is obtained by using the stripping method according to any one of claims 1-4. The crude electrode material is subjected to deep current collector removal treatment to obtain a first-stage treated material. Then, the first-stage treated material is slurried and subjected to shear ozone-assisted defluorination treatment to obtain a purified electrode material.

6. The recovery and purification method of the electrode material of the waste battery electrode sheet according to claim 5, characterized in that, The method of deep current collector removal treatment is acid treatment or alkali treatment; Preferably, when the electrode material contains a positive electrode material, the method of deep current collector removal treatment is alkali treatment; when the electrode material contains a negative electrode material, the method of deep current collector removal treatment is acid treatment.

7. The method for recycling and purification of the electrode material of the waste battery electrode sheet according to claim 5, characterized in that, The solvent during the slurrying process of the first-stage treated material is an aqueous solvent, preferably the mother liquor obtained by solid-liquid separation after stripping; Preferably, the content of the first-stage treated material in the slurry during the slurrying of the first-stage treated material is 3-5 g / mL.

8. The method for recycling and purifying the electrode material of the waste battery electrode sheet according to any one of claims 5 to 7, characterized in that, The shear ozone-assisted treatment refers to the treatment process of mixing and reacting the slurry containing the first-stage treated material and ozone through a shear mixing device; Preferably, during the shear ozone-assisted defluorination treatment process, the slurry can be cyclically input into the shear mixing device and sheared and mixed with ozone for cyclic treatment; Preferably, during the cyclic treatment stage, the slurry cyclic input end is arranged near the slurry liquid level; the slurry cyclic output end is arranged above and / or below the slurry liquid level; Preferably, the input end of the cyclic input of the slurry is arranged at and below the slurry liquid level; preferably, the distance between the input end and the liquid level is within 5 cm, preferably within 2 cm.

9. The method for recycling and purifying the electrode material of the waste battery electrode sheet according to claim 8, characterized in that, The ozone injection amount during the shear ozone-assisted defluorination treatment stage is 1-10 times of the theoretical amount, and more preferably 2-5 times; Preferably, the shear rate during the shear ozone-assisted defluorination treatment stage is 1000-6000 r / min; Preferably, the reaction temperature during the shear ozone-assisted defluorination treatment stage is 10-60 °C; Preferably, the reaction time during the shear ozone-assisted defluorination treatment stage > 30 min; Preferably, after the shear ozone-assisted defluorination treatment is completed, solid-liquid separation is carried out to obtain purified electrode materials and fluoride- and lithium-containing waste liquid respectively; after the fluoride- and lithium-containing waste liquid is defluorinated by a defluorinating agent, fluoride precipitate and lithium-containing solution are obtained respectively.

10. The waste battery electrode sheet stripping and recycling and purification device of the recycling and purification method according to any one of 5 to 9, characterized in that, It includes a box body, the box body is provided with a feed inlet, a discharge outlet (10) and a reaction zone, a blanking bin (2) and a blanking motor (1) are provided at the feed inlet, a current collector unloading belt (11) is provided at the discharge outlet, and a conveying mechanism passing through the feed inlet, the reaction zone and the discharge outlet in sequence is provided inside the box body; There is a liquid-phase reaction system in the reaction zone, an active material discharge port (13) is provided at the bottom of the reaction zone, an active material discharge pump (12) and an active material discharge valve (14) are provided at the active material discharge port (13), the conveying mechanism passes through the liquid-phase reaction system in the reaction zone, and the reaction zone is also connected with a forced circulation pump (3), a gas-liquid shear mixing device and an ultrasonic generating device (15); The gas-liquid shear mixing device includes a shear mixing device (5) with an ozone inlet (4), a solution inlet and a solution outlet, a circulating input pipeline connected to the solution inlet, and a circulating output pipeline (gas-liquid mixing pipeline 6) connected to the solution outlet, the input end (19) of the circulating input pipeline is arranged at the liquid level and below the liquid level of the liquid-phase reaction system in the reaction zone; the nozzle (7) of the circulating output pipeline is arranged at the upper part, the bottom or the side part of the reaction zone; The conveying mechanism includes a transmission chain (9), a chain guide wheel (16), a loading bin (8), a chain drive motor (17) and a driving wheel (18), a plurality of chain guide wheels (16) are fixedly connected with the box body, the transmission chain (9) is sleeved on each chain guide wheel (16) in a closed loop, loading bins (8) are arranged on each section of the transmission chain (9), and the transmission chain (9) is driven by the chain drive motor (17) and the driving wheel (18).

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