Method for recycling waste lithium ion battery and recycling system thereof

Abstract

The present application belongs to the technical field of comprehensive recycling of waste lithium ion batteries, and particularly relates to a method for recycling waste lithium ion batteries and a recycling system thereof. The method for recycling waste lithium ion batteries provided by the present application uses the heat generated by the combustion of tail gas obtained through crushing treatment and pyrolysis gas material to provide heat for pyrolysis treatment, thereby reducing energy consumption and cost. The nitrogen-making tail gas is used to provide oxygen for the combustion treatment, thereby ensuring that the organic gas in the tail gas obtained through crushing treatment and the pyrolysis gas material is fully oxidized and combusted, reducing the air intake and the emission amount of the combustion tail gas. The purified tail gas and the nitrogen-making tail gas are used for cyclic combustion treatment, thereby reducing the tail gas emission amount. The method provided by the present application can reduce the tail gas emission amount, while reducing energy consumption and cost, and achieving environmental protection standard of tail gas emission.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive recycling technology of waste lithium-ion batteries, specifically relating to a method and recycling system for the resource-based recycling of waste lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries possess advantages such as high energy density, high voltage, good cycle performance, long lifespan, low self-discharge, and environmental friendliness, and are widely used in electric vehicles, electronic information, aerospace, and energy storage. However, discarded batteries contain large amounts of toxic and hazardous substances, such as heavy metals, organic matter (methyl carbonate, ethyl carbonate), and lithium hexafluorophosphate. Direct landfilling without treatment not only poses a significant threat to the natural environment and human health but also wastes important metal resources such as copper, aluminum, and lithium. Therefore, the efficient recycling of spent lithium-ion batteries is of great significance for solving resource and environmental problems.

[0003] After dismantling the battery packs of spent lithium-ion batteries, individual battery cells are obtained. Crushing and sorting these cells is an essential step, yielding valuable components such as the casing, copper foil, aluminum foil, and black powder. However, the corresponding recycling technology system is not yet fully developed. Currently, manual dismantling is commonly used, but this poses significant health risks, has low recycling efficiency, and the electrolyte in spent lithium-ion batteries is flammable, explosive, and its stability is difficult to guarantee. Furthermore, traditional processing techniques, even at a conventional scale of 10,000 tons / year of spent lithium-ion batteries, generate exhaust emissions of up to 8,000 cubic meters per second. 3 The equipment has an installed power of 1200 kW / h and a direct processing cost of 1200 yuan / ton. The recycling of waste lithium-ion batteries suffers from drawbacks such as high emissions, high energy consumption, and high costs. Ensuring the recovery rate of each component while reducing emissions, achieving environmental compliance, and saving energy are technical challenges that need to be addressed in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for the resource recycling of waste lithium-ion batteries. The method provided by this invention can reduce exhaust emissions, while reducing energy consumption and costs, and achieving environmental compliance of exhaust emissions.

[0005] To achieve the objectives of this invention, the following technical solutions are provided: A method for the resource recycling of waste lithium-ion batteries includes the following steps: S1. The waste lithium-ion batteries are crushed to obtain battery crushed material and exhaust gas; the battery crushed material is pyrolyzed to obtain pyrolyzed solid material and pyrolyzed gas material; the crushing and pyrolysis processes are carried out under a nitrogen atmosphere. S2. The tail gas and pyrolysis gas obtained from the crushing process are subjected to combustion treatment to obtain combustion tail gas; the heat generated by the combustion treatment is used to heat the pyrolysis process. S3. The combustion exhaust gas is treated to obtain purified exhaust gas; the purified exhaust gas and the nitrogen-generating exhaust gas produced by nitrogen generation are used for the combustion treatment.

[0006] Preferably, the crushing process is carried out at a temperature of 35~60℃ and a pressure of 10~200Pa; the exhaust gas obtained from the crushing process includes organic waste gas.

[0007] Preferably, the process before crushing further includes: insulating the waste lithium-ion batteries.

[0008] Preferably, the pyrolysis treatment is performed at a temperature of 300~600℃, a pressure of 10~200Pa, and a time of 1~2h.

[0009] Preferably, the combustion treatment is carried out at a temperature of 900~1000℃ for a time of 1~3s.

[0010] Preferably, the temperature of the combustion exhaust gas is 800~900℃; the exhaust gas treatment process further includes cooling the combustion exhaust gas to 180~240℃.

[0011] Preferably, the exhaust gas treatment includes sequentially performing dust removal, defluorination, dehydration, and carbon dioxide absorption.

[0012] Preferably, the pyrolysis treatment further includes: sorting the pyrolysis solid material to obtain recyclable components and residue; and subjecting the residue to harmless treatment.

[0013] Preferably, the sorting process includes vibrating sieving, air separation, or friction stripping; the recyclable components include electrode powder, copper foil, aluminum foil, electrode column, and outer shell.

[0014] This invention provides a waste lithium-ion battery resource recycling system, including a crushing system, a pyrolysis system, a sorting system, and an environmental protection system; the environmental protection system includes a waste gas collection system, a combustion system, and a tail gas treatment system; the crushing system, pyrolysis system, and sorting system are connected in sequence; the waste gas collection system is connected to both the crushing system and the pyrolysis system; the outlet of the waste gas collection system is connected to the inlet of the combustion system; the combustion system is used for combustion reaction, and the heat generated by the combustion reaction is used as energy for the pyrolysis system; the tail gas outlet of the combustion system is connected to the tail gas treatment system.

[0015] This invention provides a method for the resource recycling of waste lithium-ion batteries. The pyrolysis furnace used in this invention does not employ electric heating; instead, it utilizes the heat generated from the combustion of the tail gas obtained from the crushing process and the pyrolysis gaseous materials in the combustion chamber on the outer wall of the furnace to heat the furnace. Compared to traditional electric heating methods, the installed power is reduced by 800 kW / h. This invention also introduces oxygen-enriched nitrogen-generating tail gas from the nitrogen generator during pyrolysis into the combustion chamber to provide oxygen, ensuring the complete oxidation and combustion of organic gases in the tail gas and pyrolysis gaseous materials. Compared to the traditional process that only introduces air, the air intake during combustion is reduced by 42.85% ((0.3 / 0.21-1) / 1). (100% = 42.85%), resulting in a 40% reduction in combustion exhaust gas emissions. This invention utilizes a portion of the purified exhaust gas obtained after exhaust gas treatment to mix with nitrogen-generating exhaust gas and return it to the combustion chamber. Compared to traditional processes that directly discharge the treated gas, this reduces chimney emissions. Furthermore, the purified exhaust gas achieves ultra-low emissions according to HJ1186-2020 standards, complying with the dual-carbon policy and offering significant economic and environmental benefits. This invention, through the combustion and heating of exhaust gas and pyrolysis gas materials obtained from crushing, the oxygen supply from nitrogen-generating exhaust gas, and the recycling and combustion of purified exhaust gas, achieves energy savings of over 20% compared to traditional processes. Attached Figure Description

[0016] Figure 1 This is a flowchart of the waste lithium-ion battery resource recycling method in Example 1. Detailed Implementation

[0017] This invention provides a method for the resource recycling of waste lithium-ion batteries, comprising the following steps: S1. The waste lithium-ion batteries are crushed to obtain battery crushed material and exhaust gas; the battery crushed material is pyrolyzed to obtain pyrolyzed solid material and pyrolyzed gas material; the crushing and pyrolysis processes are carried out under a nitrogen atmosphere. S2. The tail gas and pyrolysis gas obtained from the crushing process are subjected to combustion treatment to obtain combustion tail gas; the heat generated by the combustion treatment is used to heat the pyrolysis process. S3. The combustion exhaust gas is treated to obtain purified exhaust gas; the purified exhaust gas and the nitrogen-generating exhaust gas produced by nitrogen generation are used for the combustion treatment.

[0018] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0019] This invention involves crushing waste lithium-ion batteries to obtain crushed battery material and exhaust gas; the crushing process is carried out under a nitrogen atmosphere. As one embodiment of this invention, prior to the crushing process, the waste lithium-ion batteries are further subjected to insulation treatment to obtain pre-crushed battery cells; the insulation treatment includes: placing the waste lithium-ion batteries in a plastic mold box; and attaching insulating adhesive to the positive and negative electrodes of the waste lithium-ion batteries. This invention insulates the positive and negative terminals of the waste lithium-ion batteries to prevent them from contacting each other during the crushing process, which could lead to a short circuit.

[0020] In one embodiment of the present invention, the crushing process is carried out in a crusher; in this embodiment, the crushing process specifically includes: conveying the pre-crushed battery cells to the feeding intermediate bin of the crusher, wherein the pre-crushed battery cells in the feeding intermediate bin intermittently enter the crushing chamber, and the crusher cutter head is used to shear the pre-crushed battery cells; in one embodiment of the present invention, the temperature of the crushing process is 35~60℃, specifically 45℃, and the pressure is 10~200Pa, specifically 100Pa.

[0021] In one embodiment of the present invention, the battery crushed material includes a separator, a positive electrode, a negative electrode, a terminal block, an electrode post, and a casing; the separator contains an electrolyte, the positive electrode includes a positive electrode sheet, a positive electrode material, and a binder, and the negative electrode includes a negative electrode sheet, a negative electrode material, and a binder; the exhaust gas obtained from the crushing process includes organic waste gas, which is obtained by the volatilization of some organic solvent in the electrolyte, and the exhaust gas obtained from the crushing process is collected into a waste gas collection system.

[0022] This invention involves pyrolyzing the crushed battery material to obtain pyrolyzed solid and pyrolyzed gaseous materials; the pyrolysis is performed under a nitrogen atmosphere. In one embodiment, the pyrolysis is carried out in a pyrolysis furnace, which is an externally heated, closed furnace with a sealed, oxygen-free environment. The nitrogen is supplied by a nitrogen generator. The pyrolysis temperature is 300-600℃ (500℃), the pressure is 10-200 Pa (specifically 50 Pa), and the time is 1-2 hours.

[0023] This invention employs nitrogen-protected, oxygen-free pyrolysis to decompose organic matter at high temperatures. This avoids the risk of combustion and explosion from electrolyte volatilization and the impact of organic matter on subsequent hydrometallurgical processes, thereby improving the electrode powder stripping rate. In this invention, the electrolyte is an organic compound. Since subsequent hydrometallurgical processes require extractants, the electrolyte will consume and affect the amount and effectiveness of the extractants. The thermal decomposition of lithium hexafluorophosphate and PVDF in the electrolyte reduces the fluorine content in the black powder, thus reducing the cost of subsequent hydrometallurgical defluorination. The pyrolysis gaseous material generated during the pyrolysis process expands upon heating, which can expel air from the pyrolysis furnace and reduce the amount of nitrogen required for replenishment.

[0024] In one embodiment of the present invention, the pyrolysis solid material includes a shell, a positive electrode sheet, a negative electrode sheet, and positive and negative electrode material powders; the pyrolysis gaseous material is pyrolysis gas and pyrolysis oil obtained by pyrolysis treatment of electrolyte, separator, and binder, wherein the pyrolysis oil is gaseous pyrolysis oil; the pyrolysis gaseous material is collected to a waste gas collection system. In this embodiment of the present invention, the electrolyte in the electrolyte includes lithium hexafluorophosphate (LiPF6), and the organic solvent in the electrolyte includes carbonate solvents; the separator includes polyethylene (PE) and / or polypropylene (PP); the binder includes polyvinylidene fluoride (PVDF); the pyrolysis gaseous material includes organic waste gas and inorganic acidic gas, wherein the organic waste gas includes alkanes, short-chain olefins, and ester organic compounds; and the inorganic acidic gas includes phosphorus pentafluoride and hydrogen fluoride.

[0025] In one embodiment of the present invention, the reaction occurring during the pyrolysis treatment includes: Pyrolysis of electrolyte LiPF6: LiPF6 = LiF↓ + PF5↑; Pyrolysis of organic solvents: CxHyOz(l) = CxHyOz(g)↑; Pyrolysis of PE membrane: -[-CH2-CH2-]-n=xC+yC2~C4+zC5~C 11 +……; Pyrolysis of PP membrane: -[-CH2-CH2-CH2]-n=xC+yC2~C4+zC5~C 11 +……; Pyrolysis of PVDF binder: -[-CF2-CH2-]-n=HF↑+C (pyrolysis residual carbon)↓.

[0026] This invention uses oxygen-free pyrolysis to decompose the organic matter in waste lithium-ion batteries into pyrolysis gaseous materials at high temperatures, while a small amount of organic matter is carbonized and fixed in the pyrolysis solid materials.

[0027] This invention involves combustion treatment of the tail gas obtained from the crushing process and the pyrolysis gas material to obtain combustion tail gas; the heat generated by the combustion treatment supplies heat for the pyrolysis process. In one embodiment of this invention, the combustion treatment is carried out in the combustion chamber on the outer wall of the pyrolysis furnace, the combustion temperature is 900~1000℃, and the residence time of the tail gas and pyrolysis gas material obtained from the crushing process in the combustion chamber is 1~3s, specifically 2s; the temperature of the combustion tail gas at the outlet of the combustion chamber is 800~900℃. In another embodiment of this invention, the combustion treatment is carried out in air, and the combustion treatment is introduced with air and nitrogen-generating tail gas generated by a nitrogen generator, the volume ratio of air to nitrogen-generating tail gas is 98.5:1.5; the oxygen content of the nitrogen-generating tail gas is 30~35%.

[0028] In this embodiment of the invention, in the initial stage of the pyrolysis process, natural gas or liquefied petroleum gas is used for external heating to provide heat for the pyrolysis process; after obtaining the tail gas and pyrolysis gas material obtained from the crushing process, the invention stops external heating and uses the heat generated by the combustion of the tail gas and pyrolysis gas material obtained from the crushing process to provide heat for subsequent pyrolysis processes.

[0029] The pyrolysis process described in this invention does not use electric heating. Instead, it utilizes the heat generated by the combustion of the tail gas obtained from the crushing process and the pyrolysis gaseous materials themselves to provide heat on the outer wall of the pyrolysis furnace. Compared with the traditional electric heating method, the installed power is significantly reduced, thereby reducing the energy consumption and cost of the pyrolysis furnace.

[0030] This invention utilizes the nitrogen-generating tail gas from the nitrogen generator to assist the combustion of the tail gas and pyrolysis gas materials obtained from the crushing process. The oxygen-enriched nitrogen-generating tail gas provides oxygen for combustion, which is beneficial for the complete combustion of the tail gas and pyrolysis gas materials obtained from the crushing process, reducing the amount of combustion tail gas generated. At the same time, it reduces the amount of air introduced during the combustion process, thereby reducing the processing cost.

[0031] In one embodiment of the present invention, the organic waste gas in the pyrolysis gaseous material is burned to obtain carbon dioxide and water, while the inorganic acidic gas is not burned and is directly used as part of the combustion exhaust gas; the combustion exhaust gas includes fluorine-containing waste gas, carbon dioxide, and water; the combustion reaction includes: xC+yC2~C4+zC5~C 11 +O2=CO2+H2O; C6H5F + 4O2 = 3CO2 + 2H2O + HF; CxHyOz+(x+y / 4-z / 2)O2=xCO2+y / 2H2O.

[0032] This invention treats the combustion exhaust gas to obtain purified exhaust gas; the purified exhaust gas is used for recirculating combustion; the nitrogen generated from nitrogen production is used for the crushing and pyrolysis processes, and the nitrogen-generating exhaust gas from nitrogen production is used for the combustion process. In one embodiment of this invention, the exhaust gas treatment includes sequentially performing dust removal, defluorination, dehydration, and carbon dioxide absorption.

[0033] In one embodiment of the present invention, the dust removal includes collecting dust from the combustion exhaust gas and removing it through a bag filter. The dust in the combustion exhaust gas does not contain organic gas components, and after dust removal by the bag filter, positive and negative electrode powder and dust-removed exhaust gas are obtained respectively. After dust removal, the combustion exhaust gas is cooled to 200°C.

[0034] In one embodiment of the present invention, the defluorination is carried out in a defluorination tower, and the defluorination includes passing the dust removal tail gas into the defluorination tower, spraying an alkaline absorbent, and obtaining precipitate and defluorinated tail gas; the alkaline absorbent includes sodium hydroxide or calcium hydroxide; the precipitate includes calcium fluoride and calcium phosphate; the defluorination reaction includes: PF5 + H2O = POF3 + 2HF; 2HF + Ca(OH)₂ = CaF₂ + 2H₂O; POF3+6NaOH=Na3PO4+3NaF+3H2O; 2Na3PO4+3CaO+3H2O=Ca3(PO4)2+6NaOH; 2NaF + CaO + H2O = CaF2 + 2NaOH.

[0035] In one embodiment of the present invention, the dehydration includes liquefying the water vapor in the defluorination tail gas into liquid water to obtain dehydrated tail gas; the reaction that occurs during the dehydration is as follows: H2O(g) = H2O(l).

[0036] In one embodiment of the present invention, the carbon dioxide absorption is carried out in a carbon dioxide absorption tower. The carbon dioxide absorption includes passing the dehydrated tail gas into the carbon dioxide absorption tower, absorbing it with alkaline solution, and obtaining purified tail gas and calcium carbonate precipitate. The present invention filters the calcium carbonate precipitate and the precipitate obtained from defluorination, treating them as general solid waste. The reaction occurring during the carbon dioxide absorption is as follows: CO2 + 2NaOH = Na2CO3 + H2O; Na2CO3+Ca(OH)2=2NaOH+CaCO3↓.

[0037] This invention collects purified exhaust gas obtained after exhaust gas treatment in a buffer tank for pressure and flow stabilization. Then, a portion of the purified exhaust gas in the buffer tank, along with nitrogen-generating exhaust gas, is sent into the combustion chamber. The oxygen content of the purified exhaust gas is 8-10%, and the oxygen content of the nitrogen-generating exhaust gas is 30-35%. The purified exhaust gas and nitrogen-generating exhaust gas are mixed for combustion treatment, with a volume ratio of 1.5:98.5. This invention uses the purified exhaust gas for recirculated combustion treatment instead of direct emission, reducing chimney exhaust gas emissions, complying with the dual-carbon policy, and having good economic and environmental benefits.

[0038] The pyrolysis treatment described in this invention further includes sorting the pyrolysis solid material obtained from the pyrolysis treatment to obtain recyclable components and residue; the residue is then subjected to harmless treatment. As one embodiment of this invention, the recyclable components include electrode powder, copper foil, aluminum foil, electrode column, and shell; the sorting treatment includes vibrating sieving, air separation, or friction stripping; in this embodiment, the sorting treatment specifically includes: using a vibrating screen to sieve the pyrolysis solid material to obtain positive and negative electrode material powder and sieving residue; mixing the positive and negative electrode material powder with the positive and negative electrode powder obtained from dust removal and selling it externally; separating the sieving residue by air separation to obtain heavy components and light components, the heavy components being shell and electrode column, which are sold as waste; the light components being positive electrode sheet and negative electrode sheet; and the light components being stripped of the electrode powder by friction to obtain electrode powder, copper foil, and aluminum foil, which can be directly sold externally.

[0039] This invention provides a waste lithium-ion battery resource recycling system, including a crushing system, a pyrolysis system, a sorting system, and an environmental protection system; the environmental protection system includes a waste gas collection system, a combustion system, and a tail gas treatment system; the crushing system, pyrolysis system, and sorting system are connected in sequence; the waste gas collection system is connected to both the crushing system and the pyrolysis system; the outlet of the waste gas collection system is connected to the inlet of the combustion system; the output of the combustion system is connected to the pyrolysis system; and the tail gas outlet of the combustion system is connected to the tail gas treatment system.

[0040] In one embodiment of the present invention, the crushing system, pyrolysis system, and sorting system are connected in sequence. The crushed battery material obtained from the crushing process is transported to the pyrolysis system for pyrolysis treatment, and the pyrolysis solid material obtained from the pyrolysis treatment is transported to the sorting system for sorting treatment. The waste gas collection system is connected to both the crushing system and the pyrolysis system, collecting the tail gas obtained from the crushing process generated by the crushing system and the pyrolysis gaseous material generated by the pyrolysis system. The outlet of the waste gas collection system is connected to the inlet of the combustion system, and the collected tail gas obtained from the crushing process and the pyrolysis gaseous material are sent to the combustion system for combustion treatment. The output of the combustion system is connected to the pyrolysis system to provide heat to the pyrolysis system. The tail gas outlet of the combustion system is connected to the tail gas treatment system, and the combustion tail gas is sent to the tail gas treatment system for tail gas treatment.

[0041] Figure 1This is a flowchart of the waste lithium-ion battery resource recycling method in Example 1. To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1 S1. The positive and negative terminals of waste lithium-ion batteries are insulated to obtain pre-crushed battery cells. The pre-crushed battery cells are then fed into the intermediate feeding chamber of a crusher. The pre-crushed battery cells are intermittently fed into the crushing chamber. The pre-crushed battery cells are crushed in a sealed, oxygen-free nitrogen environment at 45°C and 100Pa to obtain battery crushed material. The battery crushed material includes a polyethylene separator, a positive electrode, a negative electrode, terminal blocks, terminals, and a shell. The polyethylene separator contains an electrolyte, which includes LiPF6 electrolyte and carbonate organic solvents. The positive electrode includes a positive electrode sheet, a positive electrode material, and a polyvinylidene fluoride binder. The negative electrode includes a negative electrode sheet, a negative electrode material, and a polyvinylidene fluoride binder. During the crushing process, some of the carbonate organic solvents in the electrolyte evaporate to produce exhaust gas. The exhaust gas obtained from the crushing process is collected in an exhaust gas collection system. S2. The crushed battery material is transported to a pyrolysis furnace for pyrolysis treatment, yielding pyrolysis solid material and pyrolysis gaseous material. The pyrolysis furnace is a closed, oxygen-free environment. During the pyrolysis treatment, nitrogen gas is introduced into the furnace using a nitrogen generator, i.e., the pyrolysis treatment is carried out under a nitrogen atmosphere. The pyrolysis treatment temperature is 500℃, the pressure is 50Pa, and the time is 1 hour. The pyrolysis solid material includes the outer shell, positive electrode sheet, negative electrode sheet, and positive and negative electrode material powders. The pyrolysis gaseous material is pyrolysis gas and gaseous pyrolysis oil obtained by pyrolysis of LiPF6 electrolyte, carbonate organic solvent, polyethylene separator, and polyvinylidene fluoride binder. The pyrolysis gaseous material includes short-chain olefins, carbonate organic compounds, phosphorus pentafluoride, and hydrogen fluoride. The pyrolysis gaseous material is collected in an exhaust gas collection system. S3. The exhaust gas and pyrolysis gas material collected by the waste gas collection system are fed into the combustion chamber on the outer wall of the pyrolysis furnace and burned at 1000°C for 2 seconds. During the combustion process, nitrogen-generating exhaust gas (containing 30% oxygen) and air are introduced. The heat generated by the combustion of the exhaust gas and pyrolysis gas material is used to heat the pyrolysis process in the pyrolysis furnace. The combustion exhaust gas produced includes fluorine-containing waste gas, carbon dioxide and water, and the temperature at the outlet of the combustion chamber is 800~900°C. S4. The combustion exhaust gas is discharged from the combustion chamber to the exhaust gas treatment system. The dust in the combustion exhaust gas does not contain organic gas components. After dust removal by a bag filter, positive and negative electrode powder and dust removal exhaust gas are obtained separately. The dust removal exhaust gas is cooled to 200°C and passed into a defluorination tower. Sodium hydroxide and calcium hydroxide are used for spray defluorination to obtain calcium fluoride and calcium phosphate precipitates and defluorination exhaust gas. The water vapor in the defluorination exhaust gas is liquefied into liquid water to obtain dehydrated exhaust gas. The dehydrated exhaust gas is passed into a carbon dioxide absorption tower and absorbed by sodium hydroxide and calcium hydroxide to obtain purified exhaust gas and calcium carbonate precipitate. The calcium carbonate precipitate and the calcium fluoride and calcium phosphate precipitates obtained from the defluorination are treated as general solid waste. The purified exhaust gas is collected in a buffer tank for pressure and flow stabilization. Then, the purified exhaust gas in the buffer tank is combined with the nitrogen generation exhaust gas and enters the combustion chamber. S5. The pyrolysis solid material obtained from the pyrolysis treatment is sorted to obtain recyclable components and residue. The residue is PF5 hydrolyzed and reacted with calcium hydroxide to produce calcium fluoride and calcium phosphate. The residue is then subjected to harmless treatment. The recyclable components include electrode powder, copper foil, aluminum foil, electrode column, and shell. The sorting process includes: using a vibrating screen to sieve the pyrolysis solid material to obtain positive and negative electrode material powder and sieving residue; the sieving residue is then separated by air classification to obtain heavy components (specifically the shell and electrode column, which are sold as waste) and light components (positive electrode sheet and negative electrode sheet); the light components are then stripped of the electrode powder by friction to obtain electrode powder, copper foil, and aluminum foil, which can be directly sold.

[0043] Comparative Example 1 S1 is basically the same as in Example 1, except that nitrogen protection was not used during the crushing process. S2 is basically the same as Example 1, except that the pyrolysis furnace uses only electric heating and the installed power of the pyrolysis furnace is 800kW / h. S3 is basically the same as in Example 1, except that the nitrogen generator produces nitrogen tail gas directly, and the tail gas and pyrolysis gas material obtained from the crushing process are burned at high temperature in the secondary combustion chamber, with only air introduced during the combustion process; the tail gas and pyrolysis gas material obtained from the crushing process are treated in a separate combustion chamber to render them harmless; the heat generated by the combustion is not used to heat the pyrolysis process. S4. It is basically the same as Example 1, except that the purified exhaust gas is directly discharged without being used for recycling and combustion treatment. S5, Same as in Example 1.

[0044] The present invention compares the oxygen consumption of the waste lithium-ion battery recycling method provided in Example 1 with that of the recycling method provided in Comparative Example 1. The results are shown in Tables 1 and 2; the amount of nitrogen introduced is 300 m³. 3 / h.

[0045] Table 1. Composition, content, and reaction equations of pyrolysis gas materials.

[0046] Table 2 Oxygen consumption and composition and content of combustion exhaust gas from pyrolysis gaseous materials

[0047] Table 1 discloses the composition and content of the pyrolysis gaseous material, as well as the reaction equations for the reaction with oxygen during the combustion process, demonstrating the ratio of the pyrolysis gaseous material to oxygen. According to Table 2, the total moles of oxygen consumed during combustion are 28848.42063 mol; in this invention, 1 m 3 The air contains 9.375 mol of oxygen, and the oxygen content of the air is 21%. The oxygen content of the nitrogen generator exhaust gas is 30%. The volume of the nitrogen generator exhaust gas introduced into this invention is 2154.015407 m³. 3 The volume of air introduced using traditional methods is 3077.164868 m³. 3 Comparison shows that the waste lithium-ion battery recycling method provided by this invention can reduce the amount of air introduced, thereby reducing energy consumption and cost.

[0048] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for the resource recycling of waste lithium-ion batteries, comprising the following steps: S1. The waste lithium-ion batteries are crushed to obtain battery crushed material and exhaust gas; the battery crushed material is pyrolyzed to obtain pyrolyzed solid material and pyrolyzed gas material; the crushing and pyrolysis processes are carried out under a nitrogen atmosphere. S2. The tail gas and pyrolysis gas obtained from the crushing process are subjected to combustion treatment to obtain combustion tail gas; the heat generated by the combustion treatment is used to heat the pyrolysis process. S3. The combustion exhaust gas is treated to obtain purified exhaust gas; the purified exhaust gas and the nitrogen-generating exhaust gas produced by nitrogen generation are used for the combustion treatment.

2. The method according to claim 1, characterized in that, The crushing process is carried out at a temperature of 35~60℃ and a pressure of 10~200Pa; the exhaust gas obtained from the crushing process includes organic waste gas.

3. The method according to claim 1, characterized in that, The process before crushing also includes: insulating the waste lithium-ion batteries.

4. The method according to claim 1, characterized in that, The pyrolysis treatment is carried out at a temperature of 300~600℃, a pressure of 10~200Pa, and a time of 1~2h.

5. The method according to claim 1, characterized in that, The combustion treatment is carried out at a temperature of 900~1000℃ for a time of 1~3 seconds.

6. The method according to claim 1, characterized in that, The temperature of the combustion exhaust gas is 800~900℃; the exhaust gas treatment process further includes cooling the combustion exhaust gas to 180~240℃.

7. The method according to claim 1, characterized in that, The exhaust gas treatment includes sequential dust removal, defluorination, dehydration, and carbon dioxide absorption.

8. The method according to claim 1, characterized in that, The pyrolysis process further includes: sorting the pyrolysis solid material to obtain recyclable components and residue; and subjecting the residue to harmless treatment.

9. The method according to claim 8, characterized in that, The sorting process includes vibrating sieving, air separation, or friction stripping; the recyclable components include electrode powder, copper foil, aluminum foil, electrode column, and outer shell.

10. A waste lithium-ion battery resource recycling system, comprising a crushing system, a pyrolysis system, a sorting system, and an environmental protection system; the environmental protection system comprises a waste gas collection system, a combustion system, and a tail gas treatment system; the crushing system, the pyrolysis system, and the sorting system are connected in sequence; the waste gas collection system is connected to both the crushing system and the pyrolysis system; the outlet of the waste gas collection system is connected to the inlet of the combustion system; the combustion system is used to perform a combustion reaction, and the heat generated by the combustion reaction is used as energy for the pyrolysis system; the tail gas outlet of the combustion system is connected to the tail gas treatment system.

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