Method and system for extracting black mass from spent lithium-ion batteries

Abstract

A method for obtaining metal salts from spent lithium-ion (Li-ion) batteries may include contacting a leaching solvent with a portion of the spent lithium-ion battery to form a first dispersion. The first dispersion is heated to a temperature in the range of 50°C to 90°C by applying microwave radiation. The temperature of the first dispersion is maintained in the range of 50°C to 90°C for a period in the range of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion. The first dispersion is then filtered to obtain a first filtrate. The first dispersion is then filtered to separate undissolved material from the first filtrate. The undissolved precipitate is dehydrated to obtain a black mass.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 407,265, filed September 16, 2022, which is incorporated by reference herein in its entirety.

[0002] The present disclosure relates generally to the field of recycling used lithium ion batteries, and more particularly to systems and methods for extracting black mass from used lithium ion batteries. [Background technology]

[0003] The adoption of powered devices, such as automobiles and power tools, has grown rapidly over the past decade. The majority of powered devices use lithium-based batteries. Given the limited lifespan of lithium-based batteries, the number of used lithium-based batteries is predicted to increase dramatically in the coming years. Furthermore, the amount of metals and other natural resources used as raw materials for lithium-based batteries is finite. As a result, recycling used lithium-based batteries to recover valuable metals can be an important source of raw materials. In addition, the materials used in lithium batteries can cause pollution of water and other resources if left in landfills, so recycling used lithium-based batteries is also environmentally important. Therefore, the development of economically viable methods for recycling used batteries is necessary to keep the cost of raw materials (and, consequently, batteries) affordable and prevent pollution caused by materials from used lithium-based batteries.

[0004] The electrodes of lithium-based batteries are primarily formed of metals such as copper, iron, and aluminum, depending on the particular battery chemistry being used. Lithium-based batteries also typically contain what is known as black mass, which generally includes graphite and salts of several valuable metals, such as iron, cobalt, manganese, nickel, copper, and aluminum (depending on the particular battery chemistry). Black mass also includes salts of lithium, which form less than about 1% by weight of scrap batteries and typically less than about 2% by weight of the battery's active mass. In some of the newer battery chemistries, black mass may also include trace amounts of other metals, such as rare earths.

[0005] The most widely used technology for recycling used lithium batteries is high-temperature chemical processing. Such high-temperature chemical processes utilize smelting, which requires high temperatures, for example, in the range of about 500°C to about 1000°C. As a result, the energy costs associated with the recycling process are high, resulting in metal recovery costs that are substantially higher than the market value of the recovered metals. Furthermore, the gases produced during smelting are often hazardous and contribute to environmental pollution. Furthermore, the amount of each metal recovered via high-temperature chemical processes is typically low compared to, for example, hydrometallurgical processes. Therefore, these technologies are not sustainable in the long term.

[0006] Some hydrometallurgical processes can provide higher yields and potentially higher purity recovered metals. However, these processes generally require heating the leach solvate at relatively high temperatures, e.g., in the range of about 80°C to about 150°C, for extended periods of time. Therefore, the energy requirements of such processes remain high. Moreover, handling high-temperature leach solvate poses certain hazards that further increase the cost of such processes.

[0007] As a result, current technologies for recycling used batteries are not cost-effective compared to technologies for obtaining these materials fresh. Therefore, there is a need for cost-effective, low-energy, sustainable, and low-carbon footprint technologies for recovering materials from used batteries. Summary of the Invention

[0008] The embodiments disclosed herein stem from the recognition that high temperatures and / or high-temperature chemical reaction techniques are not required to efficiently recover metals from spent lithium-ion batteries. The present application discloses systems and methods for extracting black mass from spent lithium-ion batteries using a leaching solvent. Because the leaching solvent used in the disclosed embodiments is an aqueous solution, microwave radiation can be used to heat the leaching solvent to a suitable temperature and maintain the temperature of the leaching solvent to reduce the time and energy required to separate the black mass from any salts and metals mixed with it. Embodiments also utilize a leaching solvent that includes an oxidizing agent to further increase the efficiency of separating metals and salts from the black mass.

[0009] The leaching solvent of the presently disclosed embodiments is selected to be capable of dissolving the various metals used in lithium-ion batteries. Thus, when spent lithium-ion battery debris is contacted with the leaching solvent at a suitable temperature, the various metals from the battery are dissolved in the leaching solvent, leaving behind black mass. The embodiments disclosed herein further utilize the recognition that once the various metals are dissolved in the leaching solvent, the black mass can be separated from the leaching solution by filtration. Therefore, advantageously, the embodiments disclosed herein enable the extraction of black mass present in lithium-ion batteries without the need to use high-temperature chemical processes, thereby substantially reducing the time, cost, and carbon footprint of recovering metals from lithium-ion batteries.

[0010] Furthermore, the leachate separated from the black mass contains salts of various valuable metals and can be further processed to obtain high purity valuable metals.

[0011] Thus, in at least one embodiment, a method for extracting black mass from spent lithium-ion (Li-ion) batteries includes contacting a leaching solvent with a portion of the spent Li-ion battery to obtain a first dispersion. The first dispersion is heated to a temperature in the range of 50°C to 90°C by applying microwave radiation. The temperature of the first dispersion is maintained in the range of 50°C to 90°C for a period in the range of 10 seconds to 5 minutes by further applying microwave radiation to the heated electrode dispersion. The first dispersion is then filtered to separate undissolved material from the first filtrate. The undissolved precipitate is dehydrated to obtain black mass.

[0012] According to at least one embodiment, a system for recycling used Li-ion batteries may include a crusher, a cleaning chamber, one or more storage tanks, two or more reaction chambers, and a controller. The crusher is configured to break cells of the used Li-ion batteries into fragments. The cleaning chamber is configured to clean the fragments, for example, using water and / or other neutral solvent(s). The one or more storage tanks are configured to store chemicals and may include at least one first storage tank that stores a first base. Two or more reaction chambers are coupled to the one or more storage tanks via one or more pumps and valves. At least a first reaction chamber of the two or more reaction chambers is coupled to a microwave generator (e.g., comprising a magnetron) configured to provide microwave generation to reactants in the first reaction chamber, and at least a second reaction chamber of the two or more reaction chambers is coupled to the first storage tank. The controller is configured to control one or more pumps and / or one or more valves to adjust the transfer rate and amount of chemicals transferred from the one or more storage tanks to corresponding ones of the two or more reaction chambers. The controller is further configured to control the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber to heat the reactants in the first reaction chamber to a temperature within a predetermined range and maintain the temperature of the reactants within the predetermined range for a predetermined period of time. The precipitate and undissolved material from the first reaction chamber are separated from the solvent to obtain a black mass.

[0013] Additional features and advantages of the subject technology will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the subject technology. The advantages of the subject technology will be realized and attained by the structures particularly pointed out in the written description and embodiments herein, as well as the accompanying drawings.

[0014] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the subject technology.

[0015] Various features of exemplary embodiments of the present disclosure are described below with reference to the drawings. The illustrated embodiments are intended to illustrate, but not limit, the present disclosure. The drawings include the following figures: [Brief explanation of the drawings]

[0016] [Figure 1] 1 illustrates a schematic diagram of an apparatus for recycling spent lithium-ion batteries, according to at least some embodiments of the present disclosure. [Figure 2] 1 shows a flowchart of a method for obtaining metal salts from spent lithium ion batteries, according to at least some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the subject technology. It should be understood that the subject technology may be practiced without some of these specific details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the subject technology.

[0018] Furthermore, while the description sets forth specific details of various embodiments, it will be understood that the description is illustrative only and should not be construed as limiting. Additionally, while particular embodiments of the present disclosure may be disclosed or illustrated in the context of recycling certain types of lithium-ion batteries, it is contemplated that such embodiments may be used with all types of lithium-ion batteries, using modifications within the scope of the present disclosure and claims. Moreover, various applications of such embodiments and modifications thereof that may occur to those skilled in the art are also encompassed by the general concepts described herein.

[0019] A typical lithium-ion battery may contain graphite powder and salts of one or more valuable metals, such as lithium, aluminum, copper, cobalt, manganese, nickel, iron, etc., depending on the battery chemistry used. Some commonly used lithium-ion battery types and the graphite and various metal contents in those battery types are provided in Tables 1-6. [Table 1] Table 1: Lithium Cobalt Oxide (LCO) Batteries [Table 2] Table 2: Lithium Nickel Cobalt Aluminum (LNCA) Batteries [Table 3] Table 3: Nickel, manganese, and cobalt ratio of 1 / 3 each in an active cathode (NMC111) battery [Table 4] Table 4: Nickel Manganese Cobalt 60 / 20 / 20% Proportion in Active Cathode (NMC622) Battery [Table 5] Table 5: Nickel Manganese Cobalt 80 / 10 / 10% Proportions in Active Cathode (NMC811) Batteries [Table 6] Table 6: Lithium Iron Phosphate (LFP) Batteries

[0020] As is evident from Tables 1-6, graphite forms a significant portion of spent Li-ion batteries. The technology disclosed herein enables economical, sustainable, and large-scale recovery of graphite and other materials contained in black mass from spent Li-ion batteries. The methods disclosed herein have low energy requirements, thereby reducing the carbon footprint of the recycling process. Furthermore, the methods disclosed herein provide high-purity graphite that, with further processing, can advantageously be used directly in the manufacture of Li-ion batteries, and enable the extraction of valuable metals from the black mass, instead of obtaining graphite from other sources.

[0021] 1 shows a schematic diagram of an apparatus 100 for recycling used lithium-ion batteries, according to at least some embodiments of the present disclosure. In some embodiments, the apparatus 100 includes a crusher 102, a washing chamber 104, one or more chemical storage tanks 106, a controller 108, one or more reaction chambers, such as a separation chamber 110, a settling chamber 112, one or more wash water tanks 114, one or more recycled water tanks 116, and one or more pumps 120.

[0022] In some embodiments, the crusher 102 is designed to break down cells of used lithium ion batteries (also referred to herein as "used batteries" for convenient reference) into pieces having dimensions ranging from about 1 mm to about 5 cm. In some embodiments, the crusher 102 may include a chamber that can be sealed and evacuated to reduce the amount of oxygen in the chamber, thereby preventing oxidation of the used battery pieces. In some embodiments, the chamber may be repressurized using an inert gas such as, for example, nitrogen or argon.

[0023] In some embodiments, the washing chamber 104 is designed to wash the used battery debris obtained from the crusher 102. Washing the debris may include processes such as, for example, washing the debris with water (e.g., distilled water), sonicating the debris in water or after drying the washed debris, drying the washed and / or sonicated debris, etc.

[0024] In some embodiments, cleaning may be performed at room temperature or at elevated temperatures. In some embodiments, cleaning may be performed in air at atmospheric pressure. Alternatively or additionally, cleaning may be performed under vacuum and / or inert atmosphere, for example, in the presence of nitrogen, argon, etc.

[0025] In some embodiments, cleaning the debris may include dispersing the used battery debris in a fluid and filtering the debris using one or more filtration processes, such as using one or more meshes, each having a different mesh size. In some embodiments, the mesh size may range from about 50 μm to about 5 mm. For example, the filtration process may include sequentially filtering the dispersion through a mesh having a mesh size of about 5 mm, followed by filtering through a mesh having a mesh size of about 1 mm, followed by filtering through a mesh having a mesh size of about 500 μm, followed by filtering through a mesh having a mesh size of about 50 μm. In some embodiments, one or more of these steps may be omitted. Alternatively or additionally, one or more filtration steps may be added to the process.

[0026] In some embodiments, the separated material after filtering through a relatively small mesh size may be removed for further processing, such as, for example, contacting the material with chemicals such as leaching chemicals, acids, neutralizing solutions (e.g., alkaline solutions, acid solutions, salt solutions, etc.), water, and / or other proprietary solutions containing one or more chemicals useful in the recycling process. In some embodiments, the undissolved material after further processing may be further separated and dried to obtain graphite powder.

[0027] In some embodiments, one or more storage tanks 106 may store chemicals such as leaching chemicals, acids, neutralizing solutions (e.g., alkaline solutions, acid solutions, salt solutions, etc.), water, and / or other proprietary solutions containing one or more chemicals useful in the recycling process.

[0028] In some embodiments, each of the one or more storage tanks 106 may be connected to two or more reaction chambers 110, 112. Furthermore, the connections between the storage tanks and the reaction chambers may include control valves that may be controlled by the controller 108. The controller 108 is configured to control the amount of chemical transferred from the storage tanks 106 to the reaction chambers 110, 112 via the control valves (or other mechanisms). For example, the controller 108 may control parameters such as the volume and / or flow rate of the chemical transferred from the storage tanks to the corresponding reaction chambers.

[0029] In some embodiments, the controller 108 may utilize control parameters, such as, for example, pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemicals in a given reaction chamber, to control the volume, mass, and / or flow rate of chemicals transferred from a storage tank to a given reaction chamber. Consequently, the system 100 may measure one or more corresponding control parameters and further include one or more sensors for measuring one or more of the controlled parameters (e.g., volume, mass, flow rate, etc.).

[0030] In some embodiments, the controller 108 may control the temperature of the material in the reaction chambers, for example, by controlling the amount of heat delivered to one of the reaction chambers or the amount of material in the reaction chamber. For example, in some embodiments, the controller 108 may control the power input to a microwave generator (e.g., comprising a magnetron) coupled to one of the reaction chambers to control the amount of microwave energy delivered to the material in the reaction chamber. The controller 108 may control the power input based on a parameter such as, for example, the temperature of the material in the reaction chamber.

[0031] In some embodiments, two or more reaction chambers may be connected to a rinse water tank 114. The connection between the reaction chambers and the rinse water tank may, in some embodiments, be controlled by a control valve. Similar to the connection between the reaction chambers and the storage tank, the controller 108 may control, via the control valve, the amount and / or flow rate of water transferred from the rinse water tank 114 to the reaction chamber based on parameters such as pH, temperature, volume, turbidity, density, and / or other parameters associated with the chemicals in a given reaction chamber.

[0032] The two or more reaction chambers, in some embodiments, are further connected to a recycled water tank 116. Upon completion of the reaction in the reaction chamber, any solid material that is generated, e.g., precipitated and / or separated in a given reaction chamber, is removed. The solid material may be removed, for example, by filtration. In some embodiments, the chemical residue, e.g., the filtrate, is neutralized using a neutralizing solution introduced into the reaction chamber from a corresponding storage tank, e.g., via control of a control valve by the controller.

[0033] In some embodiments, the neutralization process can be carried out in several steps by gradually increasing the pH of the filtrate by gradually adding a neutralizing solution to sequentially precipitate different materials. For example, a first precipitate (e.g., a first metal salt) can be obtained at a first pH, a second precipitate can be obtained at a second pH, and so on. In such embodiments, the amount and flow rate of the neutralizing solution added to the reaction chamber can be controlled by a control valve based on the pH of the contents in the reaction chamber. In some embodiments, instead of a neutralizing solution, a solid-state neutralizing chemical, for example, can be added to the reaction chamber to increase the pH of the contents of the reaction chamber.

[0034] In some embodiments, after any possible precipitates resulting from the neutralization reaction have been removed, for example by filtration, the remaining water may be further treated to bring its pH to a neutral pH and subsequently transferred to the recycled water storage tank 116.

[0035] In some embodiments, the transfer of material to or from one or more of the storage tank 106, the reaction chambers 110, 112, the rinse water tank 114, and / or the recycled water tank 116 may be facilitated by one or more pumps 120. In some embodiments, the one or more pumps 120 are coupled to a controller 108 that can control the one or more pumps 120 to control the flow rate and / or volume of material being transferred.

[0036] In one aspect of the present disclosure, a suitable apparatus, such as, for example, apparatus 100, may be utilized to recycle used batteries. Specifically, in some embodiments, an apparatus, such as apparatus 100, may be utilized to extract black mass found in used Li-ion batteries. The black mass may be further processed to obtain graphite and salts of valuable metals, such as, for example, salts of lithium, aluminum, copper, iron, nickel, cobalt, and manganese.

[0037] FIG. 2 illustrates a flowchart of a method 200 for extracting black mass from spent lithium-ion batteries, according to at least some embodiments of the present disclosure. The method 200 may include, at 202, contacting a leaching solvent with a portion of the spent Li-ion battery to obtain a first dispersion. The first dispersion is heated at 204 to a temperature in a range of about 50° C. to about 90° C. by applying microwave radiation to the first dispersion. At 206, the temperature of the heated first dispersion is maintained in a range of about 50° C. to about 90° C. for a period in a range of about 10 seconds to about 5 minutes via the controlled application of microwave radiation. At 208, the first dispersion is filtered to separate a first filtrate from undissolved material. At 210, the undissolved material is isolated to obtain metal debris and black mass.

[0038] In some embodiments, a portion of a used Li-ion battery is obtained by crushing a lithium-ion battery. The process for obtaining a suitable portion of a Li-ion battery may further include steps such as separating the crushed portion through a series of separation steps to separate materials of different sizes. For example, in some embodiments, separation may include separating coarse fragments having a size in the range of about 0.5 mm to about 5 mm by utilizing a suitable sieve, followed by further separating finer fragments having a size in the range of about 50 μm to about 0.5 mm by utilizing a second suitable sieve. In some embodiments, several (e.g., 3, 4, 5, 6, 7, or more) separation steps may be performed using sieves with different mesh sizes.

[0039] A portion of a spent Li-ion battery, such as fine debris and / or black mass, may be introduced into a reaction chamber where the fine debris and / or black mass (hereinafter collectively referred to as "black mass" for ease of reference) are contacted with a leaching solvent at 202. In some embodiments, the leaching solvent may include an acid, such as, for example, sulfuric acid, hydrochloric acid, oxalic acid, etc. In some embodiments, the leaching solvent may include two or more acids.

[0040] In some embodiments, the leaching solvent may further comprise an oxidizing agent, such as, for example, hydrogen peroxide or nitric acid. In some embodiments, the concentration of the leaching solvent may be in the range of about 0.5N to about 10N. In some embodiments, the pH of the leaching solvent may be in the range of about 0 to about 0.7. In some embodiments, the leaching solvent may have a pH of about 0. In some embodiments, the leaching solvent is introduced into the reaction chamber from a storage tank. The amount and / or flow rate of the leaching solvent introduction may be controlled via a controller.

[0041] Table 7 provides the concentrations of various materials used in the leaching solvent, according to one example. [Table 7] Table 7: Leaching solvent specifications according to the examples.

[0042] Once the leaching solvent is introduced into the reaction chamber, the leaching solvent and black mass are stirred, for example, using a stirrer (which may or may not be controlled by a controller), to form a first dispersion.

[0043] Microwave radiation is then applied to the first dispersion at 204 to heat the first dispersion to a temperature within the range of about 50° C. to about 90° C. Thus, at 206, the first dispersion may be heated to a temperature of, for example, about 50° C., about 55° C., about 60° C., about 65° C., about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., or any temperature between any two of these values.

[0044] In some embodiments, the application of microwave radiation is controlled by a controller that uses the temperature within the reaction chamber as a feedback parameter. The temperature within the reaction chamber may be determined, for example, by a temperature sensor disposed within the reaction chamber. The temperature sensor may be coupled to the controller. In some embodiments, the controller may be a proportional-integral-derivative (PID) controller, although other types of controllers are contemplated within the scope of the present disclosure.

[0045] Additionally, in some embodiments, the first dispersion in the reaction chamber is stirred while being heated. Stirring the first dispersion can help distribute the heat generated by the application of microwave radiation more evenly throughout the first dispersion. Additionally or alternatively, the first dispersion can be sonicated during the heating process, for example, by applying ultrasound.

[0046] Once the temperature of the first dispersion reaches the desired value, application of microwave radiation is continued for a period of time ranging from about 10 seconds to about 5 minutes to maintain the temperature at the desired value, at 208. For example, the temperature of the first dispersion can be maintained at the desired value for about 10 seconds, about 15 seconds, about 20 seconds, about 25 seconds, about 30 seconds, about 35 seconds, about 40 seconds, about 45 seconds, about 50 seconds, about 55 seconds, about 60 seconds, about 70 seconds, about 80 seconds, about 90 seconds, about 100 seconds, about 120 seconds, about 140 seconds, about 160 seconds, about 180 seconds, about 200 seconds, about 220 seconds, about 240 seconds, about 260 seconds, about 280 seconds, about 300 seconds, or any amount of time between any two of these values.

[0047] In some embodiments, the continuous application of microwave radiation at 204 is controlled using a controller, such as, for example, the same controller used at 204. It will be understood that the continuous application of microwave radiation does not necessarily imply constant application of microwave radiation. Thus, in some embodiments, the microwave radiation at 206 may be applied in pulses. Each pulse may have a pulse width ranging from about 0.5 seconds to 5 seconds or more. The microwave pulses may or may not have the same peak power. Thus, in some embodiments, the continuous application of microwave radiation may include applying pulses of microwave radiation and controlling parameters such as, for example, pulse width, pulse peak power, pulse rate, and the amount of time the microwave radiation is applied to the first dispersion.

[0048] Additionally, at 206, the first dispersion may be agitated and / or sonicated using ultrasound to more evenly distribute the heat generated from the application of microwave radiation throughout the first dispersion.

[0049] After maintaining the temperature of the first dispersion for a predetermined period of time, the first dispersion may be cooled to room temperature at 208. The first dispersion may then be filtered to separate undissolved materials from the first filtrate. In some embodiments, the first dispersion may be cooled to room temperature before being filtered at 208. In some embodiments, filtering the first dispersion may include passing the first dispersion through a fine filter, mesh, or sieve. In some embodiments, the filtration process may separate materials larger than a predetermined size from the first filtrate. For example, the filtration process may separate any material from the first filtrate that is larger than, for example, about 1 μm, about 5 μm, about 10 μm, or about 50 μm.

[0050] It will be appreciated that salts of valuable metals from the black mass may be dissolved in the leaching solvent. Therefore, at the end of 208, the undissolved material comprises the insoluble portion of the black mass, which may comprise primarily graphite and undissolved metal debris. Meanwhile, the first filtrate may contain metal ions. Without wishing to be bound by theory, due to the presence of an oxidizing agent in the leaching solvent, the metal ions in the first filtrate are in their highest oxidation state.

[0051] The undissolved material is then segregated at 210 to obtain undissolved metal debris and graphite. In some embodiments, segregating the undissolved material includes passing the dispersion including the undissolved material sequentially through one or more sieves of different sizes.

[0052] In some embodiments, filters, meshes, or sieves can be designed or selected to allow separation of solid materials having different sizes. For example, a first mesh, filter, or sieve can separate solid materials having a size greater than about 1 mm, a second mesh, filter, or sieve can separate solid materials having a size in the range of about 0.5 mm to about 1 mm, a third mesh, filter, or sieve can separate solid materials having a size in the range of about 0.1 mm to about 0.5 mm, a fourth mesh, filter, or sieve can separate solid materials having a size in the range of about 50 μm to about 100 μm, a fifth mesh, filter, or sieve can separate solid materials having a size in the range of about 10 μm to about 50 μm, a sixth mesh, filter, or sieve can separate solid materials having a size in the range of about 1 μm to about 10 μm, etc.

[0053] In some embodiments, the material obtained after isolation using the smallest filter, mesh, or sieve (also referred to herein as "powder") is further processed to obtain graphite. For example, the powder may be washed in one or more washing cycles using water, dilute acid, and / or dilute base to remove any adsorbed salts or metals. The washed powder may then be dehydrated to obtain graphite powder.

[0054] The present disclosure therefore provides systems and methods for obtaining black mass containing graphite from spent lithium-ion batteries. Advantageously, the graphite powder so obtained via the processes disclosed herein already meets specifications for use in lithium-based batteries. As a result, the graphite powder obtained via the processes disclosed herein can be directly utilized in the manufacture of lithium-based batteries.

[0055] The method disclosed herein is a low-temperature method that uses microwave radiation to heat a dispersion of black mass to improve energy efficiency. Furthermore, because the process does not require smelting or other high-temperature processes, there are no gas emissions and the process is essentially a zero-pollution process. Additionally, the water used in the process can also be recycled, thereby further reducing waste. [Example]

[0056] 100 kg of LCO, LNCA, NMC111, NMC622, NMC811, and LFP (25 wt % contribution) batteries were recycled using the methods disclosed herein to recover electrode metals.

[0057] Table 8 provides the amount of electrode metal recovered after the process. [Table 8] Table 8: The amount of graphite recovered from the extraction process described herein.

[0058] Further considerations In some embodiments, any of the clauses herein may depend on any one of the independent clauses or any one of the dependent clauses. In an aspect, any of the clauses (e.g., dependent or independent clauses) may be combined with any other one or more clauses (e.g., dependent or independent clauses). In an aspect, a claim may include some or all of the words (e.g., steps, actions, means, or components) recited in a clause, sentence, phrase, or paragraph. In an aspect, a claim may include some or all of the words recited in one or more clauses, sentences, phrases, or paragraphs. In an aspect, some of the words in each clause, sentence, phrase, or paragraph may be deleted. In an aspect, additional words or elements may be added within a clause, sentence, phrase, or paragraph. In an aspect, the subject technology may be implemented without utilizing some of the components, elements, functions, or operations described herein. In an aspect, the subject technology may be implemented using additional components, elements, functions, or operations.

[0059] The subject technology is exemplified, for example, according to various aspects described below. Various examples of aspects of the subject technology are described as numbered clauses (1, 2, 3, etc.) for convenience. These are provided as examples and are not intended to limit the subject technology. Note that any of the dependent clauses may be combined in any combination and placed in their own independent clauses, e.g., clause 1 or clause 5. Other clauses may be presented in a similar manner.

[0060] Clause 1. A method for extracting black mass from spent lithium ion (Li-ion) batteries, the method comprising: contacting a leaching solvent with a portion of the spent Li-ion battery to obtain a first dispersion; heating the first dispersion to a temperature in a range of 50°C to 90°C by applying microwave radiation; maintaining the temperature of the first dispersion in a range of 50°C to 90°C for a period in a range of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion; filtering the first dispersion to separate a first filtrate from undissolved material; and isolating the undissolved material to obtain metal debris and black mass.

[0061] Clause 2. The method of clause 1, wherein the black mass comprises graphite.

[0062] Clause 3. The method of clause 1, wherein the leaching solvent comprises sulfuric acid.

[0063] Clause 4. The method of clause 3, wherein the leaching solvent further comprises an oxidizing agent.

[0064] Clause 5. The method of clause 4, wherein the oxidizing agent is hydrogen peroxide.

[0065] Clause 6. The method of clause 1, wherein the leaching solvent has a pH in the range of 0 to 7.0.

[0066] Clause 7. The method of clause 1, wherein heating the first dispersion further comprises agitating the first dispersion while applying microwave radiation.

[0067] Clause 8. The method of clause 1, wherein maintaining the temperature of the first dispersion includes controlling the application of microwave radiation using a controller.

[0068] Clause 9. The method of clause 1, wherein heating the first dispersion comprises heating the first dispersion to a temperature in the range of 60°C to 80°C.

[0069] Clause 10. The method of clause 1, wherein maintaining the temperature comprises maintaining the temperature of the first dispersion within a range of 60°C to 80°C for a period within a range of 30 seconds to 5 minutes.

[0070] Clause 11. The method of clause 1, wherein the portion of the spent lithium ion battery comprises metal debris and black mass comprising graphite and metal oxides.

[0071] Clause 12. The method of clause 11, wherein filtering the first dispersion comprises filtering the first dispersion through a sieve.

[0072] Clause 13. The method of clause 1, wherein heating the first dispersion further comprises continuously stirring the first dispersion while applying microwave radiation.

[0073] Clause 14. The method of clause 1, wherein maintaining the temperature of the first dispersion further comprises continuously stirring the first dispersion while applying microwave radiation.

[0074] Clause 15. The method of clause 1, wherein isolating the undissolved material comprises passing the dispersion including the undissolved material sequentially through one or more sieves of different sizes.

[0075] Clause 16. The method of clause 15, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

[0076] Clause 17. The method of clause 16, further comprising passing the dispersion through a sieve having a minimum mesh size and then drying the remaining undissolved material to obtain graphite powder.

[0077] Clause 18. A system for recycling used lithium ion batteries, the system comprising: a crusher configured to break cells of the used lithium ion batteries into fragments; one or more storage tanks configured to store chemicals, including at least one first storage tank that stores a first base; one or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, wherein a first reaction chamber of the one or more reaction chambers is coupled to a microwave generator configured to provide microwave radiation to reactants in the first reaction chamber; a separator configured to isolate undissolved materials from the first reaction chamber; and a controller. The controller is configured to control the one or more pumps and / or the one or more valves to adjust the transfer rate and amount of chemicals transferred from the one or more storage tanks to a corresponding one of the one or more reaction chambers, and to control the microwave generator to adjust the amount of microwave radiation provided to the first reaction chamber to heat the reactants in the first reaction chamber to a temperature within a predetermined range and maintain the temperature of the reactants within the predetermined range for a predetermined period of time. The pieces are placed in a first reaction chamber for contact with a leaching solvent.

[0078] Clause 19. The system of clause 18, wherein at least one of the one or more reaction chambers includes an agitator configured to agitate reactants therein.

[0079] Clause 20. The system of clause 18, wherein the mill comprises a chamber configured to be maintained under vacuum and / or to have an inert atmosphere.

[0080] Clause 21. The system of clause 18, wherein the leaching solvent comprises sulfuric acid and an oxidizing agent.

[0081] Clause 22. The system of clause 18, wherein the predetermined temperature range is 50°C to 90°C.

[0082] Clause 23. The system of clause 18, wherein the predetermined period is in the range of 10 seconds to 5 minutes.

[0083] Clause 24. The system of clause 18, wherein the leaching solvent has a pH in the range of 0 to 7.0.

[0084] Clause 25. The system of clause 18, wherein maintaining the temperature includes maintaining the temperature of the electrode dispersion within a range of 60°C to 80°C for a period of time within a range of 30 seconds to 5 minutes.

[0085] Clause 26. The system of clause 18, wherein the separator comprises one or more sieves of different sizes through which the dispersion of undissolved material passes in sequence.

[0086] Clause 27. The system of clause 26, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

[0087] Clause 28. The system of clause 18, wherein the microwave generator comprises a magnetron.

[0088] The foregoing description is provided to enable one skilled in the art to practice the various configurations described herein. While the subject technology has been particularly described with reference to various figures and configurations, it should be understood that these are for illustrative purposes only and should not be construed as limiting the scope of the subject technology.

[0089] There may be many other ways to implement the subject technology. The various functions and elements described herein may be divided differently than shown without departing from the scope of the subject technology. Various modifications to these configurations will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other configurations. Thus, many changes and modifications may be made to the subject technology by those skilled in the art without departing from the scope of the subject technology.

[0090] It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of example approaches. Based on design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged. Some steps may be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.

[0091] As used herein, the term "about" preceding a quantity indicates a discrepancy with the quantity. The discrepancy may be caused by manufacturing tolerances or may be based on differences in measurement techniques. In some cases, the discrepancy may be up to 10% from the listed value. One of ordinary skill in the art will understand that the discrepancy with a particular quantity may be context-dependent, and thus, for example, a discrepancy in dimensions at the microscale or nanoscale may be different from a discrepancy at the meter scale.

[0092] As used herein, the phrase "at least one of" preceding a list of items modifies the list as a whole, rather than each member (i.e., each item) of the list, using the word "and" or "or" to separate any of the items. The phrase "at least one of" does not require the selection of at least one of each listed item; rather, the phrase allows for a meaning including at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrase "at least one of A, B, and C" or "at least one of A, B, or C" refers to A only, B only, or C only, any combination of A, B, and C, and / or at least one of each of A, B, and C, respectively.

[0093] Terms such as "top," "bottom," "front," and "rear" as used in this disclosure should be understood to refer to any frame of reference, rather than the typical gravitational frame of reference. Thus, the top, bottom, front, and rear surfaces may extend upward, downward, diagonally, or horizontally within the gravitational frame of reference.

[0094] Furthermore, to the extent that the terms "include," "have," or the like are used in the description or claims, such terms are intended to be inclusive in the same manner as the word "comprise" would be interpreted as "comprise" when used as a transitional term in a claim.

[0095] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0096] Reference to an element in the singular is not intended to mean "one and only one," but rather "one or more," unless specifically stated otherwise. Masculine pronouns (e.g., his) include feminine and neuter pronouns (e.g., her and its), and vice versa. The term "some" refers to one or more. Underlined and / or italicized headings and subheadings are used for convenience only and do not limit the subject technology, and are not to be referred to in connection with the interpretation of the description of the subject technology. All structural and functional equivalents to the elements of the various configurations described throughout this disclosure that are known or later become known to those skilled in the art are expressly incorporated herein by reference and are intended to be included in the subject technology. Furthermore, nothing disclosed herein is intended as a public dedication, regardless of whether such disclosure is expressly recited in the description above.

Claims

1. 1. A method for extracting black mass from spent lithium-ion (Li-ion) batteries, the method comprising: contacting a leaching solvent with a portion of the spent Li-ion battery to obtain a first dispersion; heating the first dispersion to a temperature in the range of 50°C to 90°C by applying microwave radiation; maintaining the temperature of the first dispersion within a range of 50°C to 90°C for a period of time within a range of 10 seconds to 5 minutes by further applying microwave radiation to the heated first dispersion; filtering the first dispersion to separate a first filtrate from undissolved material; and isolating said undissolved material to obtain metal debris and said black mass.

2. The method of claim 1 , wherein the black mass comprises graphite.

3. 3. The method of claim 1 or 2, wherein the leaching solvent comprises sulfuric acid.

4. The method of claim 3 , wherein the leaching solvent further comprises an oxidizing agent.

5. The method of claim 4 wherein the oxidizing agent is hydrogen peroxide.

6. 6. The method of any one of claims 1 to 5, wherein the leaching solvent has a pH in the range of 0 to 7.

0.

7. The method of any one of claims 1 to 6, wherein heating the first dispersion further comprises stirring the first dispersion while applying the microwave radiation.

8. The method of any one of claims 1 to 7, wherein maintaining the temperature of the first dispersion comprises controlling the application of microwave radiation using a controller.

9. The method of any one of claims 1 to 8, wherein heating the first dispersion comprises heating the first dispersion to a temperature in the range of 60°C to 80°C.

10. 10. The method of any one of claims 1 to 9, wherein maintaining the temperature comprises maintaining the temperature of the first dispersion in the range of 60°C to 80°C for a period in the range of 30 seconds to 5 minutes.

11. The method of any one of claims 1 to 10, wherein the portion of the used lithium ion battery comprises metal debris and black mass comprising graphite and metal oxides.

12. The method of claim 11 , wherein filtering the first dispersion comprises filtering the first dispersion through a sieve.

13. 13. The method of any one of claims 1 to 12, wherein heating the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

14. 14. The method of any one of claims 1 to 13, wherein maintaining the temperature of the first dispersion further comprises continuously stirring the first dispersion while applying the microwave radiation.

15. 15. The method of any one of claims 1 to 14, wherein isolating the undissolved material comprises passing the dispersion including the undissolved material sequentially through one or more sieves of different sizes.

16. 16. The method of claim 15, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

17. 17. The method of claim 16, further comprising passing the dispersion through a sieve having a smallest mesh size and then drying any remaining undissolved material to obtain graphite powder.

18. 1. A system for recycling used lithium ion batteries, the system comprising: a crusher configured to break cells of the used lithium ion battery into fragments; one or more storage tanks configured to store chemicals, including at least one first storage tank that stores a first base; one or more reaction chambers coupled to the one or more storage tanks via one or more pumps and valves, wherein a first reaction chamber of the one or more reaction chambers is coupled to a microwave generator configured to provide microwave radiation to reactants therein; a separator configured to isolate undissolved material from the first reaction chamber of the one or more reaction chambers; a controller, controlling the one or more pumps and / or the one or more valves to adjust the transfer rate and amount of chemicals transferred from the one or more storage tanks to corresponding ones of the one or more reaction chambers; and a controller configured to control the microwave generator to adjust the amount of microwave radiation provided to the first of the one or more reaction chambers to heat the reactants in the first of the one or more reaction chambers to a temperature within a predetermined range and maintain the temperature of the reactants within the predetermined range for a predetermined period of time; The system wherein the debris is placed in the first reaction chamber of the one or more reaction chambers for contact with a leaching solvent.

19. 20. The system of claim 18, wherein at least one of the one or more reaction chambers includes an agitator configured to agitate the reactants therein.

20. 20. The system of claim 18 or 19, wherein the grinder comprises a chamber configured to be maintained under vacuum and / or to have an inert atmosphere.

21. 21. The system of any one of claims 18 to 20, wherein the leaching solvent comprises sulfuric acid and an oxidizing agent.

22. The system of any one of claims 18 to 21, wherein the predetermined temperature range is from 50°C to 90°C.

23. A system according to any one of claims 18 to 22, wherein the predetermined period is in the range of 10 seconds to 5 minutes.

24. 24. The system of any one of claims 18 to 23, wherein the leaching solvent has a pH in the range of 0 to 7.

0.

25. 25. The system of any one of claims 18 to 24, wherein maintaining the temperature comprises maintaining the temperature of the reactants within a range of 60°C to 80°C for a period of time within a range of 30 seconds to 5 minutes.

26. 26. The system of any one of claims 18 to 25, wherein the separator comprises one or more sieves of different sizes through which the dispersion of undissolved material passes in sequence.

27. 27. The system of claim 26, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

28. The system of any one of claims 18 to 27, wherein the microwave generator comprises a magnetron.

Images