Method for recovering battery materials from used batteries

Abstract

This invention relates to the recycling of used batteries, and more particularly to a method for recovering the main components within used batteries by chemical discharge.

Description

Technical Field

[0001] The present invention relates to the recycling of used batteries, and more particularly to a method for recovering the main substances in used batteries through chemical discharge.

Background Art

[0002] Due to the global greenhouse gas reduction policy, the electric vehicle (EV) industry is rapidly developing, and as the use of energy storage systems (ESS) in cooperation with renewable energy is increasing rapidly, the demand for lithium ion batteries (LIB) is significantly increasing. In the case of such LIBs, after being used for about 10 years, they are usually discarded as the battery capacity decreases, and in the future, the generation amount of used lithium ion batteries, that is, used batteries, is also expected to increase rapidly.

[0003] As a result, the interest in the treatment and recycling of used batteries has increased, and various studies on the reuse of used batteries and lithium extraction or recovery technologies have been conducted. The existing recycling process of used batteries is roughly divided into a dry method and a wet method. The dry method melts and separates valuable metals such as cobalt and nickel by charging the entire amount into an electric furnace without separately pulverizing and sorting the used batteries, and other metals containing lithium are discharged as slag. In such a high-temperature dry process, it is difficult to recover lithium because it volatilizes and disappears or remains in the slag, and it requires high processing costs.

[0004] In the case of the wet method, after pulverizing and sorting the positive electrode material of the used battery, lithium is leached into a solution, valuable metals are separated in a solution state by solvent extraction, and lithium is produced in a metal or compound state through an electrolytic extraction or crystallization process, etc. However, the wet method itself is complicated, requires a large amount of cost, and furthermore, harmful compounds such as acids and alkaline solutions are used for lithium leaching, so there is a risk of environmental problems.

[0005] On the other hand, a technology has been devised to recover valuable metals from used batteries without using harmful compounds such as acid solutions (Patent Document 1). Specifically, the electrode recovered from waste lithium-ion batteries is heat-treated at a temperature of 180 to 450°C to melt and remove the binder, after which the separated electrode active material is obtained. Valuable metals are then recovered under aqueous solution conditions by electrolysis (capacitive de-ionization (CDI) technology). However, since a separate heat treatment step is required to melt and remove the binder from used batteries in order to recover electrode active material from used batteries, additional costs are incurred, and there is a problem that valuable metals, including lithium contained in the positive electrode active material, may be lost due to the high-temperature heat treatment. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Korean Registered Patent No. 10-2403455 Publication [Overview of the project] [Problems that the invention aims to solve]

[0007] The objective of this invention is to recover key substances from used batteries with high efficiency, speed, and low cost.

[0008] The object of the present invention is not limited to the object described above, and other objections not mentioned can be clearly understood from the following description. [Means for solving the problem]

[0009] An embodiment of the present invention relates to a battery material comprising the steps of: 1) charging a used battery; 2) dismantling the outer pouch of the charged used battery in a solution to induce chemical discharge; 3) separating the negative electrode substrate and separation membrane from the solution after the chemical discharge is completed; and 4) recovering the battery material with the solution.

[0010] The aforementioned used battery may be charged to a State of Charge (SOC) of 50 or higher.

[0011] The aforementioned solution dissolves the lithium in the charged negative electrode, and the solution may use water as a solvent, or it may use LeS (Lithium-extraction Solution) solution.

[0012] The chemical discharge may involve supplying the solution into the used battery to induce a spontaneous reaction between the lithium in the negative electrode and the solution.

[0013] The LeS may also contain water, which is a solvent that reacts with the charged negative electrode material to desorb lithium ions into the solution, and an anti-solvent that has low solubility in lithium compounds (such as anhydrous lithium hydroxide, lithium hydroxide monohydrate, and lithium carbonate) and crystallizes the lithium ions in the solution as lithium compounds.

[0014] The antisolvent may include one or more selected from the group consisting of methanol, ethanol, 2-propanol (isopropyl alcohol) (IPA), acetone, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethylene glycol, propylene glycol, methyl acetate, ethyl acetate, pentane, and heptane.

[0015] The battery material recovered from the solution may be any one of graphite, lithium (Li), copper foil, a separator membrane, or a positive electrode material.

[0016] The lithium (Li) may be in the form of a lithium compound, and the lithium compound may be Li2CO3, LiOH or LiOH.H2O.

[0017] The lithium compound recovered from the solution may be recovered by administering an alcohol-containing solvent to an aqueous lithium solution.

Advantages of the Invention

[0018] The present invention has the effect of recovering the main substances of used batteries at low cost and high efficiency through only four steps and recycling them as battery raw materials.

[0019] In addition, the present invention has the effect of recovering lithium in a low-energy-consuming and environmentally friendly manner when recovering lithium (Li) from used batteries first.

[0020] The technical effects of the present invention are not limited to those described above, and other technical effects not mentioned are those that can be clearly understood by those skilled in the art from the following description.

Brief Description of the Drawings

[0021] [Figure 1] It is a process flow diagram in the method for recovering battery materials according to an embodiment of the present invention. [Figure 2] It is a schematic diagram of the chemical discharge of a used battery during solution immersion in the method for recovering battery materials according to an embodiment of the present invention. [Figure 3] It is a process schematic diagram of the method for recovering battery materials according to an embodiment of the present invention. [Figure 4] It is a diagram showing the ICP-OES analysis results of the solution recovered by the method for recovering battery materials according to an embodiment of the present invention. [Figure 5] It is a diagram showing the FT-IR spectroscopic analysis results of the substance recovered by the method for recovering battery materials according to an embodiment of the present invention. [Figure 6]This figure shows the ICP-OES analysis results of a negative electrode recovered by a battery material recovery method according to one embodiment of the present invention. [Figure 7] This figure shows the results of XRD analysis of Li powder recovered by a battery material recovery method according to one embodiment of the present invention. [Figure 8] This figure shows the results of XRD analysis of a negative electrode material recovered by a battery material recovery method according to one embodiment of the present invention. [Figure 9] This figure shows an SEM image of a negative electrode material recovered by a battery material recovery method according to one embodiment of the present invention. [Figure 10] This is a schematic diagram of a process for recovering battery materials according to one embodiment of the present invention. [Figure 11] This figure shows a photographic image of the external case of a 60Ah battery according to one embodiment of the present invention being disassembled in an aqueous solution. [Figure 12] This figure shows the results of XRD analysis of Li powder recovered by a battery material recovery method according to one embodiment of the present invention. [Figure 13] This figure shows the XRD analysis results of the negative electrode material and positive electrode (positive electrode material + positive electrode substrate) recovered by the battery material recovery method according to one embodiment of the present invention. [Figure 14] This is a schematic diagram of a process for recovering battery materials according to another embodiment of the present invention. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described in detail so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in a variety of different forms and is not limited to the embodiments described herein. Also, the same reference numerals throughout the specification refer to the same components.

[0023] Figure 1 is a process flow diagram of a battery material recovery method according to one embodiment of the present invention.

[0024] Referring to Figure 1, a battery material recovery method according to one embodiment of the present invention includes the steps of: 1) charging a used battery (S100); 2) dismantling the outer pouch of the charged used battery in a solution to induce chemical discharge (S200); 3) separating the negative electrode substrate and separation membrane from the solution after the chemical discharge is completed (S300); and 4) recovering the battery material in the solution (S400).

[0025] The purpose of S100 is to charge the used battery, thereby moving lithium ions present in the positive electrode to the negative electrode, and inducing a spontaneous reaction in which the thermodynamically unstable charged negative electrode reacts with the solution to dissolve lithium ions. Through this, the structure of the positive electrode can be weakened by removing the lithium ions present in the positive electrode. The charging may be performed in the solution described later, or it may be pre-charged outside the solution.

[0026] In S100, the State of Charge (SOC) of the charge may preferably be 50 or higher, but may also be 60 or higher, 70 or higher, 80 or higher, 90 or higher, or in an overcharge state.

[0027] In this case, the charging speed may be set to C-rate 3 or lower.

[0028] In S100, the used battery may have a negative electrode made of graphite (C6) as the negative electrode material and copper foil (Cu foil) as the negative electrode substrate, and the positive electrode may have a lithium transition metal oxide as the positive electrode material and aluminum foil (Al foil) as the positive electrode substrate.

[0029] In S100, the charged negative electrode of the used battery may be LiC6.

[0030] S100 involves immersing the used battery in a solution for safety purposes, and the solution may be a non-volatile solution with a high specific heat. The solution is intended to prevent fires that may occur from the used battery by blocking oxygen and heat. For example, the solution may be a substance with a high specific heat, such as water or oil.

[0031] Figure 2 is a schematic diagram of the chemical discharge in S200. Referring to Figure 2, S200 induces a chemical discharge while the charged used battery is immersed in the solution. This chemical discharge is carried out by dismantling the outer pouch of the used battery, thereby supplying the solution to the inside of the used battery. More specifically, the solution flows into the inside of the used battery and reacts with the charged negative electrode. The solution reacts spontaneously with the thermodynamically unstable charged negative electrode while in contact with it, inducing a chemical discharge that releases lithium. The reaction time for the chemical discharge ranges from 10 minutes to 24 hours depending on the extent to which the outer pouch is dismantled.

[0032] In S200, the solution reacts with the charged negative electrode LiC6 to dissolve lithium in the solution, and the solution may be water, an aqueous solution in which Li is dissolved, or a LeS (Lithium-extraction solution) solution.

[0033] The solution may be supplied to the inside of the charged battery, and lithium in the negative electrode may be dissolved in the solution in the form of lithium ions, existing as a lithium solution. The lithium in the negative electrode may be lithium (or lithium ions) present in the negative electrode layered structure or lithium (or lithium ions) constituting the negative electrode SEI (Solid Electrolyte Interphase) layer and dendritic crystals (dendrite). More specifically, the solution is supplied to the inside of the charged battery, and a strong exothermic reaction between the lithium (or lithium ions) in the negative electrode and the solution causes the negative electrode material to be peeled off from the negative electrode current collector (e.g., Cu foil), which is the negative electrode substrate.

[0034] The aforementioned LeS may contain water, which is a solvent that reacts with the charged negative electrode material to desorb lithium ions into the solution, and an anti-solvent that has low solubility in lithium compounds (such as anhydrous lithium hydroxide, lithium hydroxide monohydrate, and lithium carbonate) and crystallizes the lithium ions in the solution into lithium compounds.

[0035] Pure water has high solubility for lithium, and high concentrations of lithium can accumulate during solution recycling or when processing a large number of cells. This can lead to lithium insertion into the lattice of the cathode material, potentially increasing lithium loss. However, when LeS is used as the chemical discharge solution, as in the present invention, lithium ions can easily precipitate in the form of LiOH, lowering the lithium concentration in the solution. Therefore, in the present invention, lithium insertion can be suppressed in the cathode material, ultimately increasing the lithium recovery rate.

[0036] Furthermore, since pure water has high solubility for Li, if a high-concentration Li aqueous solution is produced, the resulting high pH (for example, pH 14 or higher in the case of a 4M LiOH aqueous solution) will corrode the metals (Al, Cu, etc.) in the aqueous solution in a short time, which can lead to a decrease in the purity of the overall recovered material (positive electrode material, negative electrode material, current collector, etc.) containing lithium compounds, or necessitate an additional process to remove impurities from the recovered lithium compounds.

[0037] However, when LeS is applied as a chemical discharge solution as in the present invention, Li ions precipitate in the form of LiOH, reducing the amount of -OH ions in the solution and lowering the final pH. This has the effect of suppressing metal corrosion, reducing impurities, and increasing the overall purity of the recovered material.

[0038] Furthermore, it eliminates operational difficulties and worker safety issues caused by high pH and violent reactions that occur when processing large quantities of cells, giving it a competitive advantage in commercialization.

[0039] As a result, the pH of LeS in steps 2) to 4) can be maintained at 13 or below, even without the use of a separate pH adjusting agent, and preferably has a pH value of 7 to 13.

[0040] To obtain such effects, the antisolvent contained in the LeS of the present invention may include one or more selected from the group consisting of methanol, ethanol, 2-propanol (isopropyl alcohol) (IPA), acetone, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethylene glycol, propylene glycol, methyl acetate, ethyl acetate, pentane, and heptane.

[0041] The antisolvent contained in the LeS and the water can be mixed in a volume ratio of 7:1 to 1:7, preferably in a volume ratio of 5:1 to 1:5, and more preferably in a volume ratio of 3:1 to 1:3.

[0042] The LeS may be supplied to the inside of the charged battery, dissolving the lithium in the negative electrode and simultaneously precipitating the lithium as a salt due to the effect of the antisolvent.

[0043] Step 3) (S300) may also involve separating the solution, copper foil, and separator after the chemical discharge has been completed.

[0044] Step 4) (S400) may be the recovery of battery material from the solution, and more specifically, for safety reasons, the battery material may be separated within 10 minutes to 24 hours after the end of chemical discharge, and the recovered battery material may be any one of graphite, lithium (Li), and positive electrode material. More specifically, the graphite may be recovered first by filtering the solution under reduced pressure, and then the lithium (Li) may be recovered secondarily by drying the solution. In this case, an insoluble solvent may be added to the solution.

[0045] In step 4) (S400), the recovered lithium (Li) may be in the form of a lithium compound, and the lithium compound may be one or more lithium compounds selected from the group consisting of Li2CO3, LiOH, and LiOH.H2O.

[0046] If the lithium compound is Li2CO3, the lithium may be dried and recovered by adding carbon dioxide and a carbonate-based precipitant to the solution, the carbon dioxide may be CO or CO2, and the carbonate-based precipitant may be one or more selected from the group consisting of sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3), potassium carbonate (K2CO3), potassium bicarbonate (KHCO3), calcium carbonate (CaCO3), magnesium carbonate (MgCO3), barium carbonate (BaCO3), and dolomite (CaMg(CO3)2). Alternatively, the lithium may be precipitated by adding an insoluble solvent to the solution, filtered, and separated to recover the lithium. The insoluble solvent may be an alcohol-based solvent such as isopropyl alcohol, which has a solubility of 0 in Li2CO3. It is preferable to mix the solution and the insoluble solvent in a volume ratio of 1:1 to 1:9, and the precipitated lithium compound, Li2CO3, may be filtered (ex: using a Buchner funnel) and then dried.

[0047] If the lithium oxide is LiOH, the lithium can be recovered by precipitating the LiOH in the solution using a hydroxide-based precipitating agent or an insoluble solvent, then filtering and separating the solution. The hydroxide-based precipitating agent may be Ca(OH)2. The insoluble solvent has a solubility of 0 in LiOH, and more specifically, it may be isopropyl alcohol. It is also preferable to mix the solution and the insoluble solvent in a volume ratio of 1:1 to 1:9, and the precipitated lithium compound, which is a LiOH slurry, can be filtered (ex: using a Buchner funnel). Furthermore, to prevent the reaction of CO2 in the atmosphere with LiOH to form a Li2CO3 phase, it is preferable to dry the precipitation, filtration, and separation processes in an inert gas atmosphere or under vacuum. The inert gas may be argon (Ar) or nitrogen (N2).

[0048] Therefore, in step 4) (S400), the lithium compound recovered from the solution may be recovered by adding an alcohol-containing solvent such as isopropyl alcohol to the lithium aqueous solution.

[0049] Furthermore, in step 4) (S400), the positive electrode material recovered from the solution may be a positive electrode material and a positive electrode substrate. For example, the positive electrode material may be a lithium transition metal oxide, and the lithium transition metal oxide may be selected from the group consisting of LiCoO2, LiNiO2, Li[Ni,Co,Mn]O2, Li[Ni,Co,Al]O2, LiMn2O4, and LiFePO4. The positive electrode substrate may be aluminum foil (Al foil).

[0050] A battery material recovery method according to one embodiment of the present invention can consume minimal energy when recovering lithium. For example, assuming the conditions in Table 1 below, 1.7 kWh of energy is consumed per 1 kg of recovered lithium.

[0051] [Table 1] [Examples]

[0052] The present invention will be described in detail below through the examples provided.

[0053] Example 1. Application of a used 1Ah battery

[0054] Figure 3 is a schematic diagram of the process for recovering battery materials from a used 1Ah battery.

[0055] Referring to Figures 1 to 3, used batteries have a positive electrode composition as shown in Table 2 below, with LiNi 0.5 Co 0.2 Mn 0.3 A 1Ah pouch-type used battery (pouch cell) containing O2(NCM523), with a graphite negative electrode and LiPF6 as the electrolyte (total weight of the used battery is 17.2g) was prepared, and the prepared used battery had the Li content shown in Table 3 below. The used battery was charged to a state of charge (SOC) of 100 at 1C for 1 hour to move lithium in the layered structure of the negative electrode. The outer pouch was removed first while the used battery was placed in a tank filled with 155mL of water (aqueous solution), and chemical discharge of the used battery was performed (Figure 3, "Chemical Discharge"). After the chemical discharge of the used battery was completed, the aqueous solution in the tank (black solution = lithium aqueous solution + graphite), the copper foil of the negative electrode, and the cathode of the used battery were recovered (Figure 3, "Separation").

[0056] The recovered aqueous solution was a Black solution. The Black solution was filtered under reduced pressure to recover the graphite, and the solution from which the graphite, which was the negative electrode material, was separated (LiOH solution) was mixed with isopropyl alcohol in a 3:1 volume ratio. The precipitate that settled was filtered through a Buchner funnel, and then dried in the air to recover Li powder (Li2CO3) (Figure 3, "Drying").

[0057] [Table 2]

[0058] [Table 3]

[0059] Example 2. Application of a used 1Ah battery

[0060] The used battery was discharged in the same manner as in Example 1, except that the used battery was charged to a state of charge (SOC) of 60 at 1C to move lithium in the negative electrode layered structure.

[0061] Example 3. Application of a used 1Ah battery

[0062] The used battery was discharged in the same manner as in Example 1, except that the used battery was charged to a state of charge (SOC) of 50 at 1C to move lithium in the negative electrode layered structure.

[0063] Comparative Example 2. Recovery of battery materials using conventional technology

[0064] Using conventional technology, battery materials were recovered from a used 1Ah battery.

[0065] Specifically, the method employed consisted of steps divided into a pre-treatment process, where batteries were discharged to 0% SOC and then converted into a form that facilitated resource extraction, and a post-treatment process, where resources were extracted. The pre-treatment process involved discharging, dismantling, and crushing / grinding used batteries to produce black powder. The post-treatment process involved recovering valuable metals from this black powder through high-temperature heat treatment (>700°C) or acid treatment. As a result of using this method, a high energy consumption of 32 kWh / kg was incurred, and environmental pollution was induced by the generation of large amounts of CO2, harmful gases, and waste liquid.

[0066] Experimental Example 1: Analysis of Li content

[0067] In the above-described Example 1, the used battery charged to SOC100 was disassembled in a solution, and the graphite of the negative electrode (Before) before reacting with water (chemical discharge) was analyzed, and the graphite after reacting with water (After) was analyzed using ICP-OES (Inductively Coupled Plasma Optical Emission spectroscopy) to confirm the amount of lithium (Li) in the graphite, and the results are shown in Figure 4.

[0068] Referring to Figure 4, the amount of Li in the negative electrode of SOC100 during charging was 68,402 ppm. Therefore, the amount of Li in the negative electrode after chemical discharge was 1,022 ppm, confirming that more than 98% of the Li in the negative electrode dissolved in the aqueous solution. This confirms that more than 98% of the lithium (Li) present in the negative electrode (graphite) dissolved through a reaction with water.

[0069] Experimental Example 2. Analysis of Li Recovery

[0070] Figure 5 shows the results of Fourier transform infrared spectroscopy (FT-IR) analysis of the filtered solution obtained by filtering the water tank solution (Black solution) after the complete discharge of the used battery in Example 1, the mixed solution (Li sol:IPA 1:3) obtained by mixing the filtered solution with isopropyl alcohol in a volume ratio of 1:3, and the powdery precipitate (recovery Li salt) recovered by vacuum filtration after allowing the mixed solution to stand for 30 minutes (min) to confirm precipitation.

[0071] Referring to Figure 5, the filtering solution shows a high peak of OH groups, confirming that it exists in the form of an aqueous LiOH solution. Furthermore, the mixture (Li sol:IPA 1:3) shows a decrease in OH groups and the formation of new CH bond groups, confirming that it is a process of conversion to Li2CO3. Finally, the precipitate (recovery Li salt) shows strong C=O and CH bond groups, confirming that it exists as a Li2CO3 phase.

[0072] Furthermore, in Example 1, a used battery charged to the SOC100 was disassembled and reacted with water (chemical discharge). ICP-OES analysis was performed on the aqueous solution before (Before) and after (After) the reaction to confirm the amount of lithium in the aqueous solution, and the results are shown in Figure 6.

[0073] Referring to Figure 6, and considering that the volume of the aqueous solution is 155 mL, the Li concentration in the aqueous solution after chemical discharge is 2,182 mg / L (2,182 ppm). Therefore, the Li content in the aqueous solution after chemical discharge is 0.3382 g, which corresponds to approximately 72% of the Li amount in a 1 Ah battery (0.47 g).

[0074] Experimental Example 3. Analysis of Li component

[0075] XRD (X-ray Diffraction) analysis was performed on the Li powder (Li powder) recovered in Example 1, and the results of the XRD analysis are shown in Figure 7.

[0076] As can be seen in Figure 7, it exists in the form of Li2CO3 (see "Recovery Li2CO3" in Figure 7).

[0077] Furthermore, ICP analysis was performed on the Li powder recovered in Example 1, and the ICP analysis results are summarized in Table 4 below.

[0078] [Table 4]

[0079] Experimental Example 4. Analysis of the Anode Material

[0080] XRD analysis was performed on the graphite, which is the negative electrode material recovered in Example 1, and the results of the XRD analysis are shown in Figure 8.

[0081] Referring to Figure 8, it can be confirmed that the recovered negative electrode material is graphite (recovery graphite).

[0082] Furthermore, SEM images were analyzed of the graphite, which is the negative electrode material recovered in Example 1, and the SEM images are shown in Figure 9.

[0083] Referring to Figure 9, it can be confirmed that the recovered negative electrode material, graphite, was free of impurities and that its layered structure was maintained.

[0084] Experimental Example 5. Analysis of the recovery rate of major substances.

[0085] The recovery rates for the main substances recovered and separated in Examples 1-2 and Comparative Examples 1-2 are summarized in Table 5 below, based on Tables 2 and 3. The theoretical recovery amounts in Table 5 below are calculated from Tables 2 and 3. For example, assuming that all of the lithium (0.47g) present in the 1Ah (1,000mAh) used battery used in Example 1 was recovered, and converting this to Li2CO3, the total recoverable Li2CO3 is 2.48g. In addition, the "actual recovery amount" in Table 5 below is the actual weight measured after drying each substance recovered and separated in Example 1. On the other hand, the recovery rates for Li oxides in Table 4 below are calculated based on Li2CO3.

[0086] [Table 5] 1) Li2CO3 2) C6 (Graphite) 3) Cu (Cu foil) 4) Li x NiCoMnO2(0 <x<0.5) + Al foil 5) (SOC 100 the weight)

[0087] Example 4. Discharging of used batteries

[0088] Figure 10 is a schematic diagram of the process for recovering battery materials from a used 60Ah battery.

[0089] Referring to Figures 1, 2, and 10, used batteries have a positive electrode composition as shown in Table 6 below, with LiNi 0.6 Co 0.2 Mn 0.3A used 60Ah pouch-type battery (pouch cell) containing O2, with a graphite negative electrode and LiPF6 as the electrolyte (total weight of the used battery: 872.6g) was prepared, and the prepared used battery had the Li content shown in Table 6 below. The used battery was charged to a State of Charge (SOC) of 100 at 1C for 1 hour. As shown in Figure 11, the used battery was placed in a tank filled with 15L of water (aqueous solution), the outer pouch was removed first, and the used battery was chemically discharged ("Chemical Discharge" in Figure 10).

[0090] After the chemical discharge of the used battery is complete, the aqueous solution in the tank (Black solution = LiOH solution + graphite + positive electrode) and the copper foil (Cu foil) of the negative electrode of the used battery are separated (see "Separation" in Figure 10).

[0091] The recovered aqueous solution was Black Solution. The Black Solution was filtered under reduced pressure to recover a mixture of graphite and positive electrode (positive electrode material and Al foil). This filtered solution (LiOH solution) was then mixed with isopropyl alcohol in a 3:1 volume ratio. The settled precipitate was filtered using a Buchner funnel, and then dried in the air to recover Li powder (Li2CO3) (Figure 10, "Drying").

[0092] [Table 6]

[0093] Experimental Example 6. Analysis of Li component

[0094] XRD (X-ray Diffraction) analysis was performed on the Li powder (Li powder) recovered in Example 4, and the results of the XRD analysis are shown in Figure 12.

[0095] As can be seen in Figure 12, it exists in the form of Li2CO3 (see "Recovery Li2CO3" in Figure 12).

[0096] Experimental Example 7. Analysis of the components of the negative electrode material and positive electrode (positive electrode material and positive electrode substrate).

[0097] XRD (X-ray Diffraction) analysis was performed on the negative electrode material and positive electrode (NCM and Al) recovered in Example 4, and the results of the XRD analysis are shown in Figure 13.

[0098] Referring to Figure 13, it can be confirmed that the negative electrode material, graphite, was recovered, the positive electrode substrate, aluminum (Al), was recovered, and the LiNiO2 recovered from the positive electrode material, NCM, was recovered.

[0099] Experimental Example 7. Analysis of the recovery rate of major substances.

[0100] For the main substances recovered and separated in Example 4, the recovery rates are summarized in Table 7 below, based on Table 6.

[0101] [Table 7]

[0102] Example 5. Application of a used 1Ah battery

[0103] Instead of an aqueous solution, LeS was used as the solution. LeS was prepared by mixing isopropyl alcohol (Anti-solvent):H2O (Solvent) in a volume ratio of 3:1 and stirring at 300 rpm for 30 minutes. Unlike Example 1, where an aqueous solution was used, a 1Ah cell charged to 100% SOC was immersed in the LeS solution, and then the outer case was disassembled. The LiC6 and LeS reacted and precipitated in the form of a Li compound, settling at the bottom. Therefore, in the separation process, the precipitate, which was a mixture of the LeS solution, the Li compound, and graphite, was recovered by vacuum filtration. The precipitate was then immersed in water to dissolve the Li compound, and then separated from the graphite by vacuum filtration. The Li aqueous solution was mixed with isopropyl alcohol in a volume ratio of 1:7, and the settled Li precipitate was filtered through a Buchner funnel and dried in the air to recover Li powder (Li powder) (Li2CO3) (see "Drying" in Figure 14).

[0104] For the main substances recovered and separated in Example 5, the recovery rates are summarized in Tables 8 and 9 below, based on Table 2.

[0105] Example 6. Application of a used 1Ah battery

[0106] The preparation was carried out in the same manner as in Example 5, except that an aqueous solution of isopropyl alcohol (Anti-solvent):H2O (Solvent) in a volume ratio of 1:1 was used as LeS. The recovery rates for the main substances recovered and separated in Example 6 are summarized in Tables 8 and 9 below.

[0107] Example 7. Application of a used 1Ah battery

[0108] The preparation was carried out in the same manner as in Example 5, except that an aqueous solution of isopropyl alcohol (Anti-solvent):H2O (Solvent) in a volume ratio of 5:1 was used as LeS. The recovery rates for the main substances recovered and separated in Example 7 are summarized in Tables 8 and 9 below.

[0109] Example 8: Application of a used 1Ah battery

[0110] The preparation was carried out in the same manner as in Example 5, except that an aqueous solution of acetone (anti-solvent):H2O (solvent) in a volume ratio of 1:1 was used as the LeS. The recovery rates for the main substances recovered and separated in Example 8 are summarized in Tables 8 and 9 below.

[0111] Example 9. Application of a used 1Ah battery

[0112] The preparation was carried out in the same manner as in Example 5, except that a prepared aqueous solution of methanol (anti-solvent):H2O (solvent) = 1:1 was used as LeS. The recovery rates for the main substances recovered and separated in Example 9 are summarized in Tables 8 and 9 below.

[0113] Example 10. Application of a used 1Ah battery

[0114] The preparation was carried out in the same manner as in Example 5, except that an aqueous solution was used with LeS in a volume ratio of ethanol (anti-solvent):H2O (solvent) = 1:1. The recovery rates for the main substances recovered and separated in Example 10 are summarized in Tables 8 and 9 below.

[0115] [Table 8]

[0116] [Table 9]

[0117] Comparing Examples 5 to 10, it can be confirmed that the recovery rate of the Li compound is highest in the LeS solution using IPA within the antisolvent range.

[0118] Furthermore, ICP analysis was performed on the Li powder recovered in Example 5, and the ICP analysis results are summarized in Table 10 below.

[0119] [Table 10]

[0120] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present invention as defined in the following claims are also included within the scope of the present invention.

Claims

1. 1) Steps to charge used batteries, 2) A step of dismantling the outer pouch of the charged used battery in the solution to induce chemical discharge, 3) After the chemical discharge is completed, the steps are to separate the negative electrode substrate and the separation membrane from the solution, 4) A step of recovering battery material with the solution, Methods for recovering battery materials.

2. The method for recovering battery material according to claim 1, wherein in step 1) above, the used battery is charged to a State of Charge (SOC) of 50 or more.

3. The method for recovering battery material according to claim 1, wherein in step 2) above, the solution dissolves the lithium in the charged negative electrode.

4. The method for recovering battery material according to claim 3, wherein in step 2), the solution is either water used as a solvent or LeS (Lithium-extraction Solution) solution.

5. The method for recovering battery material according to claim 1, wherein in step 2), the chemical discharge is to supply the solution inside the used battery to induce a spontaneous reaction between the lithium in the negative electrode and the solution.

6. The method for recovering battery material according to claim 4, wherein the LeS contains water, which is a solvent that reacts with the charged negative electrode material to desorb lithium ions into a solution, and an anti-solvent that has low solubility in lithium compounds (such as lithium anhydrous hydroxide, lithium hydroxide monohydrate, and lithium carbonate) and crystallizes the lithium ions in the solution into lithium compounds.

7. The method for recovering battery material according to claim 6, wherein the antisolvent comprises one or more selected from the group consisting of methanol, ethanol, 2-propanol (isopropyl alcohol) (IPA), acetone, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), ethylene glycol, propylene glycol, methyl acetate, ethyl acetate, pentane, and heptane.

8. The method for recovering battery material according to claim 1, wherein in step 4) above, the battery material recovered from the solution is one of graphite, lithium (Li), copper foil, a separation membrane, and a positive electrode material.

9. The lithium (Li) mentioned above is Li ２ CO ３ , LiOH and LiOH.H ２ A method for recovering battery material according to claim 8, wherein the material is in the form of one or more lithium compounds selected from the group consisting of O.

10. The method for recovering battery material according to claim 8, wherein the lithium compound recovered from the solution is recovered by administering an alcohol-containing solvent to an aqueous lithium solution.

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