WO2025005665A1 - Method for reprocessing waste lithium secondary battery - Google Patents

Abstract

The present invention relates to a method for reprocessing a waste lithium secondary battery, the method comprising the steps of: primarily crushing a waste secondary battery including an electrolyte into a size of 8-15 mm; removing the separator using buoyancy while extracting the electrolyte containing lithium from the primarily crushed material using a solvent in a first extraction reactor; drying the primarily crushed material in a dryer; removing an iron component from the crushed material through a magnetic separation process; secondarily crushing the crushed material with iron components removed therefrom into a size of 5-8 mm; separating a copper electrode plate from the secondary crushed material using a second separator; thirdly crushing the copper electrode plate-separated crushed material into a size of 1-5 mm to separate an aluminum electrode plate and a positive electrode active material from the crushed material; extracting a black mass including the aluminum electrode plate and the positive electrode active material; and separating the black mass included in the lithium-containing solvent used in the electrolyte extraction step by using a separator.

Description

Method for reprocessing waste lithium secondary batteries

The present invention relates to a wet chemical pretreatment method for a spent lithium secondary battery reprocessing process, which not only recovers a high yield of lithium by extracting an electrolyte containing lithium from the shredded waste of a spent secondary battery by a chemical method while preventing fire and explosion that may occur when an undischarged cell is shredded, but also protects the atmospheric environment of a workplace by removing odor caused by the removal of the electrolyte, and recovers high-purity, high-yield black mass from the shredded waste, thereby satisfying environmental friendliness, carbon neutrality, and ESG.

With the advent of electric devices and machines that require large amounts of electricity, such as electric vehicles, mobility, and energy storage systems (ESS), large-capacity lithium secondary batteries have also emerged. However, in order to increase the efficiency of transportation and operation, the cells are stacked or packaged to form modules or packs, which are then adopted and applied to electric devices and machines that require large amounts of electricity. Electric vehicles are the best example of this.

In an environment where eco-friendly, carbon-neutral, and ESG-compliant technologies are required, a wider variety of electrical devices and mechanical devices that require large amounts of electricity will emerge, and the use of batteries is expected to increase rapidly. This trend will also lead to batteries being manufactured and distributed as various modules and packs by stacking or packaging cells. In the past, small batteries were used for small electronic devices, but now, with the emergence of large batteries for high capacity and electrical and mechanical devices, they are being adopted as modules or packs, and we are in an environment that requires a new reprocessing process technology for reprocessing waste lithium secondary batteries used in these modules and packs. Packs and modules are stacked with tens to hundreds of cells in series, which are charged with tens to hundreds of volts of current. In order to reprocess these packs and modules, the remaining electricity in the packs and modules is forcibly discharged with a discharger. However, modules and packs made by stacking tens or hundreds of cells have several to tens of undischarged cells due to errors in the BMS (Battery Management System) or cell abnormalities even when forced electrical discharge is performed. These cells can cause fire and explosion during reprocessing or crushing, making it difficult to create work efficiency and automated lines. To solve this problem and simultaneously resolve the electrolyte odor, there are cases where a high-temperature firing method and a wet method using water washing are used.

Korean Patent Publication No. 10-2020-0052761 discloses an underwater crushing process as a recycling device and method for waste lithium secondary batteries, which enables the recycling process to proceed quickly without requiring land and equipment for a discharge space by disassembling and recycling waste lithium secondary batteries directly into a recycling process without going through a discharge process.

A pretreatment method for a waste lithium secondary battery reprocessing process is disclosed, which recovers black mass through secondary crushing and tertiary crushing, transport of crushing conveyor belts using a shredder in water, drying in a kiln or rotary kiln, and classification.

Korean Patent Publication No. 10-2012-0126946 relates to a pretreatment method for a waste lithium secondary battery reprocessing process using water washing and sulfuric acid, and discloses a black mass extraction process through processes such as discharging, crushing, magnetic separation, classification, water washing, gravity separation, sulfuric acid solution peeling, and classification.

A pretreatment method for a waste lithium secondary battery reprocessing process is disclosed, which comprises the steps of crushing waste lithium secondary battery waste, such as waste lithium secondary battery electrolyte, separator, and positive and negative electrode composite fragments, into a size of 5 to 15 mm, washing the fragments with water to remove the electrolyte, separating the fragments from which the electrolyte has been removed to remove the separator, and treating the fragments from which the electrolyte and separator have been removed with a sulfuric acid solution having a concentration of 1 to 4 M to recover black mass.

Korean Patent Publication No. 10-2020-0077108 relates to a method for a waste lithium secondary battery reprocessing process using multi-stage sintering, and discloses a black mass extraction process through discharging, crushing, pulverizing, sintering, classification, and magnetic separation.

The present invention discloses a process for precipitating and discharging in brine, a process for primary crushing using a shredder cutter, a process for crushing using a cut crusher/hammer crusher/roll crusher, a process for crushing using one selected from the group consisting of a roll mill, a ball mill, a jet mill, a planetary mill, and an attrition mill, a process for multi-stage calcination ranging from 100 degrees to 1,000 degrees, a process for crushing the calcined crushed material in a lab and classifying it using a sieve, and a process for extracting black mass through a process of a magnetic separation step.

However, in the case of conventional pretreatment methods, in order to prevent explosion and fire due to crushing and pulverization of undischarged batteries for waste secondary battery processing, the electrolyte is hydrophilic and mixes with water, which not only causes water pollution, but also causes problems with the efficiency of separation rate and purity because the binder (PVDF, Polyvinylidene fluoride) increases the binding force due to the high temperature during drying. In addition, in the case of precipitation and discharge in brine and then crushing, pulverization, and classification, the quality of the air environment cannot be guaranteed due to the odor of the electrolyte, and the process is complicated and exposes the user to the risk of water pollution caused by the brine for discharge and sulfate. In the case of high-temperature calcination, it can cause other economic losses and environmental pollution, such as oxidation of aluminum plates due to high temperatures, economic losses due to oxidation loss of expensive lithium, and CO2 generation. In addition, the conventional process is complex and does not provide an answer to the question of whether it is a technology process that satisfies ESG based on the atmospheric environment, water quality environment, and carbon neutrality. Therefore, it is necessary to develop a technology process that is environmentally friendly, carbon neutral, and ESG-satisfying, capable of preventing explosions and fires in undischarged lithium secondary batteries in the field, has a simple process, enables high separation rate and high purity black mass extraction, and has a high recovery rate of expensive lithium.

The present invention aims to solve the above-mentioned problems and other problems. Another object is to provide a method for reprocessing waste lithium secondary batteries using a chemical method.

Conventionally, waste lithium secondary battery finished products are crushed and pulverized to make shreds and extract black mass. However, during crushing, undischarged cells are exposed to fire and explosion, and since they are soaked in electrolyte, the shreds turn into cakes when crushed and pulverized, making efficient separation impossible, and there were limitations in extracting high-purity black mass. Therefore, a process of extraction through drying, washing, and calcination is used to remove electrolyte and polymer raw materials. In the case of the drying method, acetone gas, which is a unique property of lithium secondary battery electrolyte, is generated during crushing and pulverization, which causes serious adverse effects on the health of workers due to air pollution in the factory, and the process due to washing requires additional environmental facilities and operating costs to prevent water pollution. In the case of the incineration method (KILN), a high-temperature treatment process of 400 to 1,000 degrees is performed in a rotary kiln to remove the binder used to attach the electrolyte, separator, and positive active material of the secondary battery positive plate and the carbon of the negative plate. At this time, not only is there an oxidation loss of lithium, which is an expensive raw material, and ionization of fluorine of PVDF, which is a binder, but also various heavy metal ions of other waste secondary battery raw materials are generated. Therefore, excessive environmental facilities and operating costs are required to prevent air emissions. In addition, the aluminum plates of the high-temperature treated shredded material in the rotary kiln go through a crushing and pulverizing process using a mill in an oxidized state. At this time, the oxidized aluminum plates are also pulverized by the mill process. In the process of separating the black mass, aluminum plates, and copper plates using a fine vibrating screen, undivided copper plates and undivided aluminum oxide are mixed into the black mass, lowering the purity of the black mass. Therefore, they act as impurities when manufacturing nickel sulfate (NiSO4), cobalt sulfate (CoSO4), and lithium hydroxide (LiOH), which are raw materials for secondary battery cathodes, using a wet process. Therefore, the cost required for washing to remove impurities increases and environmental pollution occurs, which are factors that limit the achievement of economic feasibility. In addition, high-temperature treatment causes excessive energy consumption and a large amount of carbon dioxide, which has a significant impact on the global atmospheric environment.

Accordingly, the method for reprocessing waste lithium secondary batteries according to one embodiment of the present invention sequentially separates the waste secondary batteries by removing the electrolyte through a chemical method that does not change the properties of each raw material, and then crushing and separating them, thereby simplifying the complex process and improving productivity in a way that satisfies the environment, carbon neutrality, and ESG, thereby providing a preprocessing method for the waste lithium secondary battery reprocessing process consisting of an automated line.

According to one aspect of the present invention to achieve the above or other purposes, a method for reprocessing a spent lithium secondary battery may be provided, including the steps of: first crushing a spent secondary battery containing an electrolyte into 8 to 15 mm pieces; extracting an electrolyte containing lithium from the first crushed particles using a solvent in an extraction reactor while removing a separator using buoyancy; drying the first crushed particles in a dryer; removing iron components from the crushed particles through a magnetic separation process; second crushing the particles from which the iron components have been removed into 5 to 8 mm pieces; separating a copper plate from the second crushed particles using a separator; third crushing the particles from which the copper plates have been separated into 1 to 5 mm pieces to separate an aluminum plate and a cathode active material from the particles; extracting a black mass containing the aluminum plate and the cathode active material; and separating a black mass contained in a solvent used in the lithium-containing electrolyte extraction step using a separator.

According to one aspect of the present invention, the solvent introduced into the extraction reactor in the step of extracting the electrolyte is methanol, ethanol, tetrachloromethane, trichloromethane, dichloromethane, pentachloroethane, 1,1,1,2 tetrachloroethane, 1,1,2,2 tetrachloroethane, 1,1,2 trichloroethane, 1,1,1 trichloroethane, tetrachloroethene, trichloroethene, cis 1,2 dichloroethene, trans 1,2 dichloroethene. It may be at least one selected from the group consisting of 1,1 dichloroethene, 1,2 dichloroethane, 1,1 dichloroethane, and NMP (N-Methyl-2-pyrrolidinone).

According to one aspect of the present invention, the solvent used in the step of extracting the electrolyte can be mixed at a ratio of 0.5 to 10 times the weight of the crushed material.

According to one aspect of the present invention, the temperature of the extraction reactor in the step of extracting the electrolyte may be 10 to 150°C.

According to one aspect of the present invention, after the electrolyte extraction step, the method may further include a step of fractionating the solvent containing the electrolyte into a solvent and an electrolyte containing lithium (Li) through a fractionating separator; and a step of re-supplying the fractionated solvent to the electrolyte extraction step.

According to one aspect of the present invention, the step of drying the primary crushed material can be performed at a temperature of 20°C to 200°C.

The method for reprocessing waste lithium secondary batteries according to the present invention is described as follows.

According to at least one of the embodiments of the present invention, after primary shredding of scrap, lithium secondary battery waste is extracted from the scrap in a chemical wet process in a reactor containing a solvent through an automated process, thereby increasing economic efficiency through lithium reprocessing and removing the odor of the electrolyte, thereby protecting the working environment and the atmospheric environment from the odor of the electrolyte.

According to at least one of the embodiments of the present invention, the scrap from which the electrolyte and lithium are extracted can be efficiently crushed and pulverized, thereby having the advantage of extracting high yield and high purity black mass.

According to at least one of the embodiments of the present invention, the electrolyte and solvent containing lithium extracted in the electrolyte extraction process can be separated, recovered, and reused to increase cost efficiency, and the electrolyte containing lithium has an advantage in that it can create additional profits through reprocessing. That is, after crushing waste lithium secondary batteries, the electrolyte is extracted in a reactor, and after the electrolyte extraction, the wet lithium secondary battery crushed matter is dried in a process to remove the odor of the electrolyte, and at the same time, crushing and separation are performed quickly and efficiently, and the solvent used in the electrolyte extraction has an advantage in that it can extract black mass that is reused through reprocessing.

Further scope of applicability of the present invention will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art, it should be understood that the detailed description and specific examples, such as preferred embodiments of the present invention, are given by way of example only.

Figure 1 is a flow chart of a method for reprocessing waste lithium secondary batteries related to the present invention.

Figure 2 is a photograph of waste lithium secondary battery fragments related to the present invention.

Figure 3 is a photograph of a separation membrane separated from the primary crushed material related to the present invention.

FIG. 4 is a photograph of a third crushed battery fragment related to the present invention.

Figure 5 is a photograph of a separated and extracted lithium electrolyte related to the present invention.

Figure 6 is a photograph of a separated black mass related to the present invention.

Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing symbols, the same or similar components will be given the same reference numerals and redundant descriptions thereof will be omitted. The suffix "part" used for components in the following description is assigned or used interchangeably only for the convenience of writing the specification, and does not in itself have a distinct meaning or role. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. In addition, the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, it should be understood that terms such as “comprises” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

The present invention relates to a wet chemical process for extracting high-yield, high-purity black mass by first crushing and pulverizing spent lithium secondary batteries containing electrolyte, and processing the crushed materials from which the electrolyte is extracted, and recovering the electrolyte including lithium with a high yield. When spent lithium secondary batteries containing electrolyte are first crushed, the electrolyte is wetted in the crushed materials, and the crushed materials turn into a cake by the electrolyte, so it is difficult to extract high-purity black mass and high-yield black mass. In addition, since the electrolyte mainly uses an aromatic organic solvent having a ketone structure, such as diethyl carbonate (DEC) and dimethyl carbonate (DMC), there has been a difficulty in securing an air environment in the workplace due to the odor of the electrolyte during crushing and pulverization.

In order to solve these problems, in one embodiment of the present invention, a pretreatment process for recycling a lithium secondary battery whose life has ended (EoL) is disclosed, which effectively crushes and pulverizes a spent lithium secondary battery containing an electrolyte by using a chemical method, to extract high-quality black mass with high purity and high separation rate and an electrolyte containing lithium. More specifically, first, when shredding spent lithium secondary batteries, undischarged cells can cause fire and explosion, so a process for extracting electrolyte containing lithium using a wet chemical method while preventing fire and explosion is disclosed, second, a process for drying a solvent in spent lithium secondary battery shreds from which the electrolyte has been removed is disclosed, third, a process for separating black mass extracted together with lithium, electrolyte, and solvent is disclosed, fourth, a process for separating the solvent and electrolyte containing lithium is disclosed, and fifth, a process for reusing the separated solvent is provided. In this process, high-purity, high-yield black mass is extracted from primary shreds through secondary shredding and separation processes, and an automated process for recovering electrolyte containing lithium at a high yield is provided.

In particular, it is a process for recovering black mass and electrolyte containing lithium through a low-temperature chemical wet method while preventing fire and explosion caused by undischarged cells during the first crushing, and provides an automated process for extracting lithium and black mass through a chemical process that satisfies environmental friendliness, carbon neutrality, and ESG.

That is, a method is disclosed for efficiently separating the main components of a spent lithium secondary battery, such as a pouch packaging or can, an electrolyte, a separator, aluminum as a positive electrode plate and a positive electrode active material, and copper as a negative electrode plate and a negative electrode active material, during the first crushing for reprocessing of a spent lithium secondary battery according to the present invention, thereby preventing fire and explosion due to undischarged cells, and efficiently separating the main components of a spent lithium secondary battery, such as a pouch packaging or can, an electrolyte, a separator, and a positive electrode plate, and a negative electrode active material, through an electrolyte extraction step. In addition, since the spent lithium secondary battery regeneration process according to an embodiment of the present invention can ensure safety against fire and explosion, etc., it is possible to perform a continuous process, and thus has the advantage of sealing the machines for all processes to prevent dust and air pollution, separating and extracting only black mass, and improving purity and separation amount.

FIG. 1 is a flow chart of a method for reprocessing waste lithium secondary batteries related to the present invention. Hereinafter, a method for reprocessing waste lithium secondary batteries according to one embodiment of the present invention will be described with reference to FIG. 1.

The above-mentioned waste lithium secondary battery reprocessing method comprises the steps of: first crushing waste secondary batteries containing electrolyte into 8 to 15 mm (S110); extracting lithium-containing electrolyte from the first crushed waste using a solvent in an extraction reactor while removing a separator using buoyancy (S120); drying the first crushed waste in a dryer (S130); removing iron components from the crushed waste through a magnetic separation process (S140); second crushing the crushed waste from which the iron components have been removed into 5 to 8 mm (S150); separating copper plates from the second crushed waste using a separator (S160); third crushing the crushed waste from which the copper plates have been separated into 1 to 5 mm (S170) to separate cathode active material from the aluminum plates; and removing black mass containing the aluminum plates and cathode active material. It is performed including a step of extracting (S180) and a step of separating (S190) the black mass included in the solvent used in the step of extracting the electrolyte containing lithium using a separator.

At this time, the step of crushing the first crushed material is crushed using a shredder, and the first to third crushings are crushed into gradually smaller sizes. The step of drying the first crushed material is performed at a temperature of 20°C to 160°C. At this time, it can be performed using a dryer such as a kiln furnace, a vacuum dryer, a thermal dryer, or a general dryer.

If the temperature is lower than 20℃, there is a problem that drying is not performed properly, and if it is higher than 160℃, the binder (PVDF) can further increase the bonding strength between the aluminum plate, positive electrode active material, and black mass, so the drying temperature is limited to 20 to 160℃.

At this time, FIG. 2 is a photograph of waste lithium secondary battery shreds related to the present invention, FIG. 3 is a photograph of a separator separated from the first shreds related to the present invention, and FIG. 4 is a photograph of the third shredded battery shreds related to the present invention.

In addition, the solvent introduced into the extraction reactor in the step of extracting the electrolyte is methanol, ethanol, tetrachloromethane, trichloromethane, dichloromethane, pentachloroethane, 1,1,1,2 tetrachloroethane, 1,1,2,2 tetrachloroethane, 1,1,2 trichloroethane, 1,1,1 trichloroethane, tetrachloroethene, trichloroethene, cis 1,2 dichloroethene, trans 1,2 dichloroethene, It may be at least one selected from the group consisting of 1,1 dichloroethene, 1,2 dichloroethane, 1,1 dichloroethane, and NMP (N-Methyl-2-pyrrolidinone). Depending on the solvent used, ignition can be prevented in advance by additionally purging with nitrogen during electrolyte extraction.

The solvent used in the step of extracting the electrolyte may be mixed at a ratio of 0.5 to 10 times the weight of the crushed material. If the amount of the solvent is less than 0.5 times the weight of the crushed material, the solvent may be completely absorbed by the separator of the crushed material, so that it simply becomes a cake in a wet state, making it difficult to extract the electrolyte. If the amount of the solvent is more than 10 times the weight, there is a problem of excessive cost.

In addition, in one embodiment of the present invention, the temperature of the extraction reactor for extracting the electrolyte from the waste lithium secondary battery scrap is 10 to 150°C for 2 to 30 minutes, and the process of transporting the electrolyte while stirring with a stirring machine such as a screw or a screw, or transporting the electrolyte while spraying the electrolyte, may be performed by using a machine (line, batch, etc.) that combines an impact tool using vibration or ultrasonic waves. If the temperature of the extraction reactor is higher than 150°C, the binder (PVDF) may melt, and considering the boiling point of the solvent, it is preferable to set it higher than 10°C.

Meanwhile, in one embodiment of the present invention, after the electrolyte extraction step, the solvent containing the electrolyte is fractionated into a solvent and an electrolyte containing lithium (Li) through a fractionating separator (S123), and the fractionated solvent is re-supplied to the electrolyte extraction step (S125) so that the solvent can be reused. More specifically, in a solvent in which lithium and the electrolyte are mixed, the solvent or a mixed solvent of two or more and the electrolyte containing lithium are separated from the electrolyte containing lithium using a fractionating separator or a layer separator at a temperature range of 20 to 150°C. If the temperature is lower than 20°C, it is difficult to extract the electrolyte, and if it is higher than 150°C, even if the electrolyte is extracted, the binder may melt. Therefore, in one embodiment of the present invention, the electrolyte extraction temperature is limited to 20 to 150°C.

Hereinafter, a method for reprocessing waste lithium secondary battery containing electrolyte according to one embodiment of the present invention will be described in more detail.

First, the spent lithium secondary battery waste containing the electrolyte is crushed and pulverized. This is the step of crushing the spent lithium secondary battery waste containing the electrolyte. The spent lithium secondary batteries are crushed into 8 to 15 mm sizes using a shredder. The 8 to 15 mm crushed materials are fed into an extraction reactor with 2.5 times the weight ratio of the crushed materials through a screw for 10 minutes, and a mixing process is added to increase the efficiency of the reaction to extract the electrolyte. During this process, the separator is automatically separated and the separated separator is removed.

The above extracted crushed material was sent to a dedicated drying machine and dried. At this time, the drying hot air was 30℃ to 45℃. If the drying temperature is 20℃ or lower, the drying speed of the solvent is low, making it difficult to achieve the target processing amount per hour. Even if the drying temperature is 45℃ or higher, the remaining binder, PVDF, did not affect the separation rate and purity of aluminum and the cathode material due to the increase in binder caused by heat curing.

Production and separation rate by drying temperature of shredded material division 30 degrees 35 degrees 40 degrees 45 degrees Separation rate 99% 99% 99% 99% water 99% 99% 99% 99%

Table 1 shows the results of measuring the production yield and separation rate according to the drying temperature of the crushed material. Referring to Table 1, it can be seen that the separation rate and purity at 30 to 45 degrees are both 99%.

After extracting the electrolyte, the residual separator was removed from the dried shreds using a separator to obtain waste secondary battery shreds. The obtained shreds were subjected to a belt magnetic separator process to obtain negative and positive electrode shreds and pulverized products from which iron components such as battery electrodes and cans were removed.

The crushed material from which the electrolyte, separator, can, and electrodes were removed was crushed into 5 to 8 mm pieces through a secondary shredder, and then the copper plate was removed through a separator. In order to separate the negative active material from which the copper plate was removed and the positive active material attached to the aluminum plate, the aluminum and positive active material were crushed into 1 to 5 mm pieces through a pin mill process, and the aluminum and positive active material were easily separated. The separated aluminum plate, positive active material, and negative active material were passed through an 80 to 120 mesh vibrating sieve to separate the aluminum plate, and the black mass with a purity of 99% or more could be separated and extracted. At this time, a photograph of the separated and extracted lithium electrolyte is shown in Fig. 5, and a photograph of the separated and extracted black mass is shown in Fig. 6.

The electrolyte and solvent containing lithium obtained through the electrolyte extraction process contain some black mass, which can be separated using a centrifuge. The electrolyte and solvent containing lithium were separated using the separator. Afterwards, the separated black mass cake was sent to a dryer to perform a drying process.

The mixed solvent containing the electrolyte was sent to a fractionator and fractionated at a temperature of 35 to 45°C to separate the solvent and the electrolyte containing lithium (Li). The Li content of the extracted electrolyte was 90% of the ratio input during battery manufacturing and varied depending on the amount of reaction solvent input.

The recovery rate of the solvent recovered using the fractionator was 98%, and the recovered separated solvent was sent back to the electrolyte extraction reactor and recycled.

The above detailed description should not be construed as restrictive in all respects but should be considered as illustrative. The scope of the invention should be determined by a reasonable interpretation of the appended claims, and all changes coming within the equivalent scope of the invention are intended to be embraced within the scope of the invention.

One embodiment of the present invention can be used in the technical field of reprocessing waste lithium secondary batteries to recover lithium at a high yield by extracting an electrolyte containing lithium from shredded waste secondary batteries by a chemical method.

Claims (6)

A step of first crushing a spent secondary battery containing electrolyte into pieces of 8 to 15 mm; A step of removing a separator by using buoyancy while extracting an electrolyte containing lithium from the first crushed material using a solvent in an extraction reactor; A step of drying the above primary crushed material in a dryer; A step of removing iron components from the crushed material through a magnetic separation process; A step of secondary crushing of the above-mentioned crushed material from which the iron components have been removed into 5 to 8 mm pieces; A step of separating the copper plate from the secondary crushed material using a separator; A step of separating the aluminum plate and positive electrode active material from the shredded material by crushing the shredded material from which the copper plate is separated into 1 to 5 mm pieces for the third time; A step of extracting black mass containing the above aluminum electrode plate and positive electrode active material; and A method for reprocessing a spent lithium secondary battery, comprising a step of separating black mass contained in a solvent used in the lithium-containing electrolyte extraction step using a separator. In claim 1, In the step of extracting the electrolyte, the solvent introduced into the extraction reactor is methanol, ethanol, tetrachloromethane, trichloromethane, dichloromethane, pentachloroethane, 1,1,1,2 tetrachloroethane, 1,1,2,2 tetrachloroethane, 1,1,2 trichloroethane, 1,1,1 trichloroethane, tetrachloroethene, trichloroethene, cis 1,2 dichloroethene, trans 1,2 dichloroethene, A method for recycling a spent lithium secondary battery, characterized in that at least one is selected from the group consisting of 1,1 dichloroethene, 1,2 dichloroethane, 1,1 dichloroethane, and NMP (N-Methyl-2-pyrrolidinone). In claim 2, A method for reprocessing waste lithium secondary batteries, characterized in that the solvent used in the step of extracting the electrolyte is mixed at a ratio of 0.5 to 10 times the weight of the crushed material. In claim 2, A method for reprocessing waste lithium secondary batteries, characterized in that the temperature of the extraction reactor in the step of extracting the electrolyte is 10 to 150°C. In claim 1, After the above lithium-containing electrolyte extraction step, The above lithium-containing electrolyte and solvent are separated into a solvent and an electrolyte containing lithium (Li) through a separator; and A method for recycling a spent lithium secondary battery, characterized in that it further comprises a step of re-supplying the separated solvent to the electrolyte extraction step. In claim 1, A method for reprocessing waste lithium secondary batteries, characterized in that the step of drying the first crushed material is performed at a temperature of 20°C to 150°C.

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