Method and system for separating black mass from electrodes of used lithium ion batteries

Abstract

A method for separating black mass from electrodes of a used lithium-ion battery includes separating electrode pieces from remaining material of a portion of a used lithium-ion battery. The electrode pieces are heated to a temperature in the range of about 200°C to about 350°C for a predetermined period of time to obtain preheated electrode pieces. The preheated electrode pieces are placed in a neutral liquid to obtain a first suspension. Ultrasonic vibrations are applied to the first suspension to separate the black mass and binder from the metal pieces. The metal pieces, binder material, and black mass are then isolated from the electrode pieces to obtain black mass.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 420,959, filed October 31, 2022, the entirety of which is incorporated herein by reference for all purposes.

[0002] The present disclosure relates generally to the field of recycling used lithium ion batteries, and specifically to systems and methods for extracting black mass from used lithium ion batteries, and more specifically for separating black mass from electrodes of 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. Considering the service life of lithium-based batteries, the number of used lithium-based batteries is predicted to increase exponentially over the next few years. Furthermore, the amount of metals and other natural resources used as raw materials for lithium-based batteries is finite. Consequently, recycling used lithium-based batteries to recover valuable metals can be an important source of raw materials. In addition, because materials used in lithium batteries can cause pollution of water and other resources if left in landfills, recycling used lithium-based batteries is also environmentally important. Therefore, in order to keep the cost of raw materials (and, consequently, batteries) affordable and prevent pollution caused by materials from used lithium-based batteries, it is necessary to develop economically viable methods for recycling used 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] One challenge in recovering black mass from spent lithium-ion batteries is the PVDF binder used to bind the black mass from the electrode surface. As discussed herein, one approach involves heating the electrode at high temperatures (e.g., above 600°C to 800°C) to break the PVDF bonds. However, heating any material above 500°C results in a degradation of the material's properties. For example, heating a metal electrode in the presence of a metal salt can result in the diffusion of metal ions from the salt into the metal electrode. Furthermore, during the process, graphite present in the black mass along with the lithium can be lost (e.g., through oxidation as carbon dioxide), and the remaining elements (Co, Ni) are recovered in the form of alloys. Reusing these elements for various applications involves additional chemical operations that are costly.

[0006] 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

[0007] The embodiments disclosed herein stem from the realization that high temperature and / or high temperature chemical reaction techniques are not required to effectively separate black mass from electrodes of spent lithium ion batteries. This application discloses a system and method for separating black mass from electrodes of spent lithium ion batteries using a combination of heat and ultrasonic vibration. Because the ultrasonic vibrations used in the disclosed embodiments can also generate heat when used in water, ultrasonic vibrations can be utilized to reduce the time and energy required to separate black mass from the PVDF binder and metal electrode pieces.

[0008] Preheated debris from used lithium-ion batteries, which may include metals, binders, and black mass, is contacted with water, and ultrasonic vibrations are applied to the water and debris. Embodiments of the present disclosure utilize the recognition that a combination of heating and ultrasonic vibrations separates the black mass from the binder and metal electrode strips. Therefore, advantageously, 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. The black mass can then be processed to extract various valuable metal salts, which can be further processed to obtain high-purity valuable metals.

[0009] Thus, in at least one embodiment, a method for extracting black mass from a spent lithium-ion (Li-ion) battery includes separating electrode pieces from the remainder of a portion of the material of the spent lithium-ion battery. The electrode pieces include black mass, binder material, and metal pieces that form an electrode of the lithium-ion battery. The method further includes heating the electrode pieces to a temperature in the range of about 200°C to about 350°C for a predetermined period of time to obtain preheated electrode pieces, and placing the preheated electrode pieces in water to obtain a first suspension. Ultrasonic vibrations are applied to the first suspension to separate the black mass and binder material from the metal pieces. The metal pieces, binder material, and black mass separated from the electrode pieces are then isolated.

[0010] According to at least one embodiment, a system for recycling used Li-ion batteries may include a crusher, a first separator, one or more heating chambers, an ultrasonic generator, an ultrasonic treatment chamber coupled to the ultrasonic generator, a second separator, and a controller. The crusher is configured to break cells of the used Li-ion battery into fragments. The first separator is configured to separate the fragments of the used Li-ion battery into electrode pieces and remaining materials. The electrode pieces include black mass, binder material, and metal pieces. The one or more heating chambers are configured to heat the electrode pieces to a predetermined temperature for a predetermined period of time. The ultrasonic treatment chamber is configured to apply ultrasonic vibrations generated by the ultrasonic generator to a first suspension of preheated electrode pieces in water. The second separator is configured to separate the metal pieces, binder material, and black mass. The controller is configured to control the temperature in the one or more heating chambers. The controller is further configured to control the ultrasonic generator, often to control the frequency and intensity of the ultrasonic vibrations applied to the first suspension.

[0011] 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 structure particularly pointed out in the written description and embodiments herein, as well as the accompanying drawings.

[0012] 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.

[0013] Various features of illustrative 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. [Brief explanation of the drawings]

[0014] [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 extracting black mass from electrodes of spent lithium-ion batteries, according to at least some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] 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.

[0017] 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 listed in Tables 1-6.

[0018] [Table 1]

[0019] [Table 2]

[0020] [Table 3]

[0021] [Table 4]

[0022] [Table 5]

[0023] [Table 6]

[0024] As evident from Tables 1-6, black mass, including graphite, forms a significant portion of spent Li-ion batteries. The technology disclosed herein enables the recovery of black mass from spent Li-ion batteries, thereby enabling the economical, sustainable, and large-scale recovery of graphite, valuable metals, and valuable metal salts. The methods disclosed herein have low energy requirements, thereby reducing the carbon footprint of the recycling process. Furthermore, the methods disclosed herein enable the recovery of black mass from electrode pieces and the production of black-mass-free electrode metal strips. The recovered black mass can then be further processed to extract valuable metals and valuable metal salts, which can advantageously be used directly in the manufacture of Li-ion batteries, instead of obtaining these materials anew from other sources.

[0025] 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, one or more heating chambers 104, a heater 106 coupled to the heating chamber(s), an ultrasonic treatment chamber 108, an ultrasonic generator 110 coupled to the ultrasonic treatment chamber 108, a controller 120 configured to control the heater 106 and the ultrasonic generator 110, a first separator 112, and a second separator 116.

[0026] 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 can 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 can be repressurized using an inert gas such as, for example, nitrogen or argon.

[0027] The first separator 112 is configured to separate the electrode pieces within the used battery debris from the remainder of the used battery material. For example, the first separator 112 separates plastic, polymer, separator, and bulk black mass debris from the electrode pieces. In some embodiments, the first separator 112 may use techniques such as eddy current-based sorting, spectral imaging-based sorting, magnetic sorting, density separation, or a combination thereof. The electrode pieces separated in the first separator 112 are transferred to one or more heating chambers 104 for further processing.

[0028] In some embodiments, one or more heating chambers 104 are designed to heat the electrode pieces received from the first separator 112. The one or more heating chambers 104 may be coupled to a heater 106 configured to provide heat to the one or more heating chambers 104. In some embodiments, the one or more heating chambers may be configured to maintain an inert atmosphere using, for example, nitrogen, argon, and / or other inert gas(es). In some embodiments, the one or more heating chambers are configured to be maintained under vacuum. In some embodiments, the one or more heating chambers are configured to provide an oxidizing atmosphere. For example, in some embodiments, the one or more heating chambers may have a higher oxygen partial pressure relative to atmospheric air. In some embodiments, the one or more heating chambers may be evacuated and repressurized with substantially pure oxygen.

[0029] The heater 106 may be controlled using the controller 120 and may be configured to heat the electrode strips in one or more heating chambers to a temperature in the range of about 200° C. to about 350° C. For example, the electrode strips may be heated to a temperature of about 200° C., about 210° C., about 220° C., about 230° C., about 240° C., about 250° C., about 260° C., about 270° C., about 280° C., about 290° C., about 300° C., about 310° C., about 320° C., about 330° C., about 340° C., about 350° C., or any temperature between any two of these values.

[0030] In some embodiments, the heater 106 is configured to provide sufficient heat to maintain the temperature of the electrode strips in one or more heating chambers within a range of about 200° C. to about 350° C. for a period ranging from about 30 minutes to about 120 minutes. For example, the temperature of the electrode strips may be maintained for a period of about 30 minutes, about 40 minutes, about 50 minutes, about 60 minutes, about 70 minutes, about 80 minutes, about 90 minutes, about 100 minutes, about 110 minutes, about 120 minutes, or any amount of time between any two of these values.

[0031] The electrode tips thus heated (also referred to herein as "preheated electrode tips") may then be transferred to the sonication chamber 108. The sonication chamber 108 is coupled to an ultrasonic generator 110 configured to provide ultrasonic vibrations to the sonication chamber 108 (or contents therein). In some embodiments, the sonication chamber 108 may also be coupled to a heater 106 to allow heating of the contents of the sonication chamber 108.

[0032] In some embodiments, the sonication chamber 108 is configured to receive a first suspension of electrode pieces in a neutral liquid. In some embodiments, the neutral liquid may include water, alcohol, dimethyl sulfoxide (DMSO), dimethylacetamide, N,N-dimethylformamide, or any other suitable liquid for suspending the electrode pieces therein. Thus, in some embodiments, the sonication chamber 108 may be coupled to a storage tank (not shown) that provides the suitable liquid used to suspend the electrode pieces to form the first suspension. In some embodiments, the suitable liquid may be deionized water. In some embodiments, the suitable liquid may be an aqueous solution of ethyl alcohol. In some embodiments, the suitable liquid may be weakly alkaline or weakly acidic. In some embodiments, the suitable liquid may be neutral, for example, having a pH of about 7.

[0033] In some embodiments, water or other suitable liquid is introduced into sonication chamber 108 at room temperature. In some embodiments, water or other suitable liquid is introduced into sonication chamber 108 at a lower or higher temperature. For example, the temperature of water or other suitable liquid introduced into sonication chamber 108 can range from about 10°C to about 100°C.

[0034] In some embodiments, the preheated electrode pieces are introduced into the sonication chamber 108 after the introduction of water or other suitable liquid. In some embodiments, the preheated electrode pieces are introduced into the sonication chamber 108 simultaneously with the water or other suitable liquid. In some embodiments, the preheated electrode pieces are suspended in water or other suitable liquid to form a first suspension in a separate chamber (not shown), and the first suspension is then introduced into the sonication chamber 108. In such embodiments, the first suspension may be heated before being introduced into the sonication chamber 108. Alternatively, or additionally, the first suspension may be heated within the sonication chamber 108 to increase or maintain the temperature of the first suspension chamber.

[0035] The ultrasonic generator 110 is coupled to a controller 120, which controls the frequency and / or intensity of the ultrasonic vibrations provided to the ultrasonic treatment chamber 108. In particular, the controller 120 can control the amount of ultrasonic energy received by the ultrasonic treatment chamber 108.

[0036] In some embodiments, the ultrasonic vibrations received by the sonication chamber can have a frequency in the range of about 25 kHz to about 100 kHz. For example, the ultrasonic vibrations received by the sonication chamber 108 can have a frequency of about 25 kHz, about 30 kHz, about 35 kHz, about 40 kHz, about 45 kHz, about 50 kHz, about 55 kHz, about 60 kHz, about 65 kHz, about 70 kHz, about 75 kHz, about 80 kHz, about 85 kHz, about 90 kHz, about 95 kHz, about 100 kHz, or any other frequency between any two of these values.

[0037] In some embodiments, the ultrasonic generator is controlled so that the first suspension receives ultrasonic energy at a rate ranging from about 10 W / kg to about 1000 kW / kg. For example, the rate of ultrasonic energy received by the first suspension can be about 10 W / kg, about 50 W / kg, about 100 W / kg, about 200 W / kg, about 300 W / kg, about 400 W / kg, about 500 W / kg, about 750 W / kg, about 1000 W / kg, about 1250 W / kg, about 1500 W / kg, about 2000 W / kg, about 5000 W / kg, about 10 kW / kg, about 20 kW / kg, about 30 kW / kg, or about 40 kW / kg. W / kg, about 50 kW / kg, about 60 kW / kg, about 70 kW / kg, about 100 kW / kg, about 125 kW / kg, about 150 kW / kg, about 200 kW / kg, about 300 kW / kg, about 400 kW / kg, about 500 kW / kg, about 600 kW / kg, about 700 kW / kg, about 800 kW / kg, about 900 kW / kg, about 1000 kW / kg, or any ratio between any two of these values.

[0038] In some embodiments, ultrasonic vibrations are provided to the first suspension for a period ranging from about 10 minutes to about 100 minutes, for example, about 10 minutes, about 20 minutes, about 30 minutes, about 40 minutes, about 50 minutes, about 60 minutes, about 70 minutes, about 80 minutes, about 90 minutes, about 100 minutes, or any amount of time between any two of these values.

[0039] The second separator 116 is configured to separate metal pieces, binder material, and black mass resulting from the ultrasonic treatment of the electrode pieces. In some embodiments, the second separator 116 can include multiple sieves of different sizes through which the first suspension is sequentially passed. In some embodiments, each of the multiple sieves includes a mesh with a different mesh size. In some embodiments, the mesh size can be in the range of about 5 mm to about 0.01 mm. For example, the multiple sieves can have a mesh size of about 5 mm, about 1 mm, about 500 μm, about 50 μm, about 10 μm, or any value between any two of these sizes.

[0040] Upon passing through the second separator 116, the solids in the first suspension are separated into electrode pieces (e.g., metal pieces such as copper pieces), black mass fragments, black mass powder, and graphite powder. The black mass fragments may include graphite and salts of valuable metals.

[0041] Therefore, 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, specifically black mass from the electrodes of used Li-ion batteries. The black mass can 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.

[0042] FIG. 2 illustrates a flowchart of a method 200 for extracting black mass from spent lithium-ion batteries, specifically from electrodes of the lithium-ion battery, according to at least some embodiments of the present disclosure. The method 200 may include, at 202, separating electrode pieces from the remainder of a portion of the spent lithium-ion battery material, the electrode pieces including black mass, metal pieces, and binder material. The electrode pieces are heated at 204 to a temperature in the range of about 200° C. to about 350° C. using a suitable heating means to obtain preheated electrode pieces. At 206, the preheated electrode pieces are placed in a neutral liquid to obtain a first suspension. At 208, ultrasonic vibrations are applied to the first suspension to separate the black mass and binder material from the metal pieces. At 210, the metal pieces, binder material, and black mass are isolated.

[0043] In some embodiments, electrode pieces from used Li-ion batteries are obtained by crushing the lithium-ion batteries. The process for obtaining electrode pieces from Li-ion batteries may include, at 202, steps such as separating the crushed pieces 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.

[0044] In some embodiments, the separation step may be performed in 202 in a first separator that may be sealed and evacuated to reduce the amount of oxygen in the chamber, thereby preventing oxidation of the debris (including the electrode pieces) of the used battery. In some embodiments, the chamber may be repressurized using an inert gas, such as nitrogen or argon.

[0045] In some embodiments, the separating step, at 202, may include techniques such as eddy current-based sorting, spectral imaging-based sorting, magnetic sorting, density separation, or a combination thereof.

[0046] The electrode strips may be introduced into one or more heating chambers at 204, where the electrode strips are heated to a suitable temperature. In some embodiments, the heating step may be performed under an inert atmosphere, for example, using nitrogen, argon, and / or other inert gas(es). In some embodiments, the heating step may be performed under a vacuum. In some embodiments, the heating step may be performed under an oxidizing atmosphere. For example, in some embodiments, one or more heating chambers may have a higher oxygen partial pressure relative to atmospheric air. In some embodiments, one or more heating chambers may be evacuated and repressurized with substantially pure oxygen.

[0047] In some embodiments, a suitable temperature may range from about 200° C. to about 350° C. For example, the electrode strips may be heated to a temperature of about 200° C., about 210° C., about 220° C., about 230° C., about 240° C., about 250° C., about 260° C., about 270° C., about 280° C., about 290° C., about 300° C., about 310° C., about 320° C., about 330° C., about 340° C., about 350° C., or any temperature between any two of these values.

[0048] In some embodiments, the temperature of the electrode strip may be maintained at a suitable temperature for a period ranging from about 30 minutes to about 120 minutes. For example, the temperature of the electrode strip may be maintained for a period of about 30 minutes, about 40 minutes, about 50 minutes, about 60 minutes, about 70 minutes, about 80 minutes, about 90 minutes, about 100 minutes, about 110 minutes, about 120 minutes, or any amount of time between any two of these values.

[0049] The resulting preheated electrode strips may then be placed in a neutral liquid at 206 to obtain a first suspension. In some embodiments, the neutral liquid may include water, alcohol, dimethyl sulfoxide (DMSO), dimethylacetamide, N,N-dimethylformamide, or any other suitable liquid for suspending the electrode strips therein. In some embodiments, the neutral liquid may be deionized water. In some embodiments, the suitable liquid may be an aqueous solution of ethyl alcohol. In some embodiments, the suitable liquid may be an aqueous solution of any one or more of dimethyl sulfoxide (DMSO), dimethylacetamide, or N,N-dimethylformamide. In some embodiments, the suitable liquid may be neutral, for example, having a pH of about 7. In some embodiments, instead of a neutral liquid, the liquid used for the first suspension may be weakly alkaline or weakly acidic.

[0050] At 208, ultrasonic vibrations are applied to the first suspension, for example, by applying ultrasonic vibrations to a sonication chamber containing the first suspension. The ultrasonic vibrations may be generated using an ultrasonic generator. The temperature of the first suspension may, in some embodiments, be maintained during application of the ultrasonic vibrations. In some embodiments, the first suspension may be at room temperature during application of the ultrasonic vibrations. In some embodiments, the first suspension may be at a lower or higher temperature during the ultrasonic vibrations. For example, the temperature of the first suspension may be maintained to be within a range of about 10°C to about 100°C.

[0051] In some embodiments, the ultrasonic vibrations applied at 208 can have a frequency in the range of about 25 kHz to about 100 kHz. For example, the ultrasonic vibrations applied at 208 can have a frequency of about 25 kHz, about 30 kHz, about 35 kHz, about 40 kHz, about 45 kHz, about 50 kHz, about 55 kHz, about 60 kHz, about 65 kHz, about 70 kHz, about 75 kHz, about 80 kHz, about 85 kHz, about 90 kHz, about 95 kHz, about 100 kHz, or any other frequency between any two of these values.

[0052] In some embodiments, the ultrasonic generator is controlled so that the first suspension receives ultrasonic energy at a rate ranging from about 10 W / kg to about 1000 kW / kg. For example, the rate of ultrasonic energy received by the first suspension can be about 10 W / kg, about 50 W / kg, about 100 W / kg, about 200 W / kg, about 300 W / kg, about 400 W / kg, about 500 W / kg, about 750 W / kg, about 1000 W / kg, about 1250 W / kg, about 1500 W / kg, about 2000 W / kg, about 5000 W / kg, about 10 kW / kg, about 20 kW / kg, about 30 kW / kg, or about 40 kW / kg. W / kg, about 50 kW / kg, about 60 kW / kg, about 70 kW / kg, about 100 kW / kg, about 125 kW / kg, about 150 kW / kg, about 200 kW / kg, about 300 kW / kg, about 400 kW / kg, about 500 kW / kg, about 600 kW / kg, about 700 kW / kg, about 800 kW / kg, about 900 kW / kg, about 1000 kW / kg, or any ratio between any two of these values.

[0053] In some embodiments, the ultrasonic vibrations are applied to the first suspension for a period ranging from about 10 minutes to about 100 minutes, for example, about 10 minutes, about 20 minutes, about 30 minutes, about 40 minutes, about 50 minutes, about 60 minutes, about 70 minutes, about 80 minutes, about 90 minutes, about 100 minutes, or any amount of time between any two of these values.

[0054] Upon application of ultrasonic vibrations for a predetermined period of time, the black mass and binder material are separated from the metal pieces. At 210, the metal pieces, black mass, and binder material are then isolated, for example, in a second separator.

[0055] The isolating step at 210 can include sequentially passing the first suspension through a plurality of sieves of different sizes. In some embodiments, each of the plurality of sieves includes a mesh with a different mesh size. In some embodiments, the mesh size can be in the range of about 5 mm to about 0.01 mm. For example, the plurality of sieves can have a mesh size of about 5 mm, about 1 mm, about 500 μm, about 50 μm, about 10 μm, or any value between any two of these sizes.

[0056] In some embodiments, sieves can be designed or selected to allow separation of solid materials having different sizes. For example, a first sieve can separate solid materials having a size greater than about 5 mm, a second sieve can separate solid materials having a size in the range of about 5 mm to about 1 mm, a third sieve can separate solid materials having a size in the range of about 1 mm to about 0.5 mm, a fourth sieve can separate solid materials having a size in the range of about 500 μm to about 100 μm, a fifth sieve can separate solid materials having a size in the range of about 100 μm to about 50 μm, a sixth mesh, filter, or sieve can separate solid materials having a size in the range of about 50 μm to about 10 μm, etc.

[0057] The black mass obtained in 210 can be further processed to obtain graphite and salts of valuable metals. Additionally, the metal flakes obtained in 210 can be further processed to obtain pure metal flakes that can then be reused to make battery electrodes.

[0058] Therefore, the present disclosure provides systems and methods for obtaining black mass comprising graphite and metal salts from electrodes of spent lithium-ion batteries. Advantageously, the graphite powder so obtained via the processes disclosed herein already meets specifications for use in lithium-based batteries. Consequently, the graphite powder obtained via the processes disclosed herein can be directly utilized in the manufacture of lithium-based batteries. Even more advantageously, the systems and methods described herein can provide organic-free metal flakes, which can therefore be further processed to obtain pure metal flakes that can be reused to manufacture battery electrodes.

[0059] The methods disclosed herein are carried out at relatively low temperatures and do not require smelting or other high temperature processes. As a result, no gases are emitted and the process is essentially a zero-pollution process.

[0060] 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 one or more other 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.

[0061] The subject technology is illustrated according to various aspects, for example, as 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.

[0062] Clause 1. A method, comprising: separating electrode pieces from the remainder of a portion of material of a used lithium ion battery, the electrode pieces including black mass, metal pieces, and binder material; heating the electrode pieces to a temperature in the range of about 200°C to about 350°C for a predetermined period of time to obtain preheated electrode pieces; placing the preheated electrode pieces in a neutral liquid to obtain a first suspension; applying ultrasonic vibrations to the first suspension to separate the black mass and binder material from the metal pieces; and isolating the metal pieces, binder material, and black mass. Clause 2. The method of clause 1, wherein the predetermined period of time is in the range of about 30 minutes to about 120 minutes. Clause 3. The method of clause 1 or 2, wherein the ultrasonic vibrations have a frequency in the range of about 25 kHz to about 100 kHz. Clause 4. The method of any one of clauses 1-3, wherein applying ultrasonic vibrations comprises applying ultrasonic vibrations for a period of time in the range of about 10 minutes to about 100 minutes. Clause 5. The method of any one of clauses 1-4, wherein heating the electrode pieces comprises heating the electrode pieces in a vacuum. Clause 6. The method of any one of clauses 1-5, wherein heating the electrode strips comprises heating the electrode strips in the presence of an inert gas. Clause 7. The method of any one of clauses 1 to 6, wherein the neutral liquid in which the preheated electrode pieces are placed has a temperature in the range of about 10°C to about 100°C. Clause 8. The method of any one of clauses 1 to 7, wherein the neutral liquid has a pH of about 7. Clause 9. The method of any one of clauses 1 to 8, wherein the neutral liquid comprises one or more selected from the group consisting of deionized water, dimethyl sulfoxide (DMSO), dimethylacetamide, and N,N-dimethylformamide. Clause 10. The method of any one of clauses 1 to 9, wherein applying ultrasonic vibrations to the first suspension comprises applying ultrasonic energy in the range of about 10 W to about 100 kW per kg of first suspension, or in the range of about 50 W to about 1000 W per kg of first suspension, or in the range of about 100 W to about 500 W per kg of first suspension, or in the range of about 1 kW to about 5 kW per kg of first suspension, or in the range of about 5 kW to about 10 kW per kg of first suspension, or in the range of 10 kW to about 50 kW per kg of first suspension, or in the range of about 50 kW to about 100 kW per kg of first suspension. Clause 11. The method of any one of clauses 1 to 10, further comprising heating and / or maintaining the temperature of the first suspension within the range of about 10°C to about 100°C. Clause 12. The method of clause 11, wherein maintaining the temperature of the first suspension is for a duration that the ultrasonic vibrations are applied. Clause 13. The method of any one of clauses 1 to 12, wherein isolating the metal flakes, binder material and black mass comprises passing the first suspension sequentially through one or more sieves of different sizes. Clause 14. The method of clause 13, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm. Clause 15. The method of clause 14, further comprising passing the first suspension through a sieve having a smallest mesh size and then drying the remaining undissolved material to obtain graphite powder. Clause 16. The method of any one of clauses 1-15, wherein the remaining material of the portion of the used lithium ion battery includes fragments of one or more of plastic, metal separator, polymer separator, and electrolyte. Clause 17. 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; a first separator configured to separate the fragments of the used lithium ion batteries into electrode fragments and a remainder of the material, the electrode fragments including black mass, metal fragments, and binder material; one or more heating chambers configured to heat the electrode fragments to a predetermined temperature for a predetermined period of time; an ultrasonic treatment chamber coupled to an ultrasonic generator, the ultrasonic treatment chamber configured to apply ultrasonic vibrations generated by the ultrasonic generator to a first suspension of preheated electrode fragments in a neutral liquid; a second separator configured to separate the metal fragments, binder material, and black mass; and a controller configured to control the ultrasonic generator coupled to the ultrasonic treatment chamber to control the temperature in the one or more heating chambers and to control the application of the ultrasonic vibrations. Clause 18. The system of clause 17, further comprising a mixing chamber configured to mix the preheated electrode pieces with the neutral liquid to obtain the first suspension. Clause 19. A system as described in clause 17 or 18, wherein the controller is configured to control the frequency and intensity of the ultrasonic vibrations applied to the ultrasonic treatment chamber and to control the amount of time the ultrasonic vibrations are applied. Clause 20. A system described in any one of clauses 17 to 19, wherein one or more heating chambers are configured to be maintained under vacuum and / or to have an inert atmosphere. Clause 21. The system of any one of clauses 17 to 20, wherein the grinder is configured to be maintained under vacuum and / or to have an inert atmosphere. Clause 22. The system of any one of clauses 17 to 21, wherein the predetermined temperature is in the range of about 200°C to about 350°C. Clause 23. The system of any one of clauses 17 to 22, wherein the predetermined period is in the range of 30 minutes to approximately 120 minutes. Clause 24. A system described in any one of clauses 17 to 23, wherein the ultrasonic vibrations have a frequency in the range of about 25 kHz to about 100 kHz. Clause 25. The system of any one of clauses 17 to 24, wherein the ultrasonic vibrations are applied to the first suspension for a period of time in the range of about 10 minutes to about 100 minutes. Clause 26. The system of any one of clauses 17 to 25, wherein the ultrasonic vibrations have an energy in the range of about 10 W to about 100 kW per kg of the first suspension, or in the range of about 50 W to about 1000 W per kg of the first suspension, or in the range of about 100 W to about 500 W per kg of the first suspension, or in the range of about 1 kW to about 5 kW per kg of the first suspension, or in the range of about 5 kW to about 10 kW per kg of the first suspension, or in the range of 10 kW to about 50 kW per kg of the first suspension, or in the range of about 50 kW to about 100 kW per kg of the first suspension. Clause 27. The system of any one of clauses 17 to 26, further comprising a heater coupled to the ultrasonic treatment chamber, the heater configured to raise and / or maintain the temperature of the first suspension at a temperature within the range of about 10°C to about 100°C. Clause 28. The system of clause 27, wherein the temperature of the first suspension is maintained for a period of time within a range of about 10 minutes to about 100 minutes. Clause 29. The system of any one of clauses 17 to 28, wherein the second separator is configured to separate the metal pieces, binder material and black mass by sequentially passing the first suspension through one or more sieves of different sizes. Clause 30. The system of clause 29, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

[0063] 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 specifically 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.

[0064] 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.

[0065] 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 of the 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.

[0066] As used herein, the term "about" preceding a quantity indicates a difference from the quantity. The difference may be caused by manufacturing tolerances or may be based on differences in measurement techniques. In some cases, the difference may be up to 10% from the listed value. Those skilled in the art will understand that the difference in a particular quantity may be context-dependent; therefore, for example, a difference in dimensions on the microscale or nanoscale may be more different than a difference on the meter scale.

[0067] 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.

[0068] 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.

[0069] Furthermore, to the extent that terms such as "include," "have," and the like are used in the specification or claims, such terms are intended to be inclusive in the same manner as "comprise" would be interpreted as "comprise" when used as a transitional term in a claim.

[0070] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0071] Reference to an element in the singular is intended to mean "one and only one," but "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 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 above specification.

Claims

1. 1. A method comprising: Separating electrode pieces from the remainder of material of a portion of a used lithium ion battery, the electrode pieces including black mass, metal pieces, and binder material; heating the electrode strips to a temperature in the range of about 200°C to about 350°C for a predetermined period of time to obtain preheated electrode strips; placing the preheated electrode pieces in a neutral liquid to obtain a first suspension; applying ultrasonic vibrations to the first suspension to separate the black mass and the binder material from the metal pieces; and isolating the metal pieces, the binder material, and the black mass.

2. The method of claim 1 , wherein the predetermined period of time is in a range of about 30 minutes to about 120 minutes.

3. The method of claim 1 or 2, wherein the ultrasonic vibrations have a frequency in the range of about 25 kHz to about 100 kHz.

4. 4. The method of claim 1, wherein applying the ultrasonic vibrations comprises applying the ultrasonic vibrations for a period of time in a range from about 10 minutes to about 100 minutes.

5. The method of any one of claims 1 to 4, wherein heating the electrode pieces comprises heating the electrode pieces in a vacuum.

6. The method of any one of claims 1 to 5, wherein heating the electrode strips comprises heating the electrode strips in the presence of an inert gas.

7. 7. The method of claim 1, wherein the neutral liquid in which the preheated electrode pieces are placed has a temperature in the range of about 10°C to about 100°C.

8. The method of any one of claims 1 to 7, wherein the neutral liquid has a pH of about 7.

9. 9. The method of claim 1, wherein the neutral liquid comprises one or more selected from the group consisting of deionized water, dimethyl sulfoxide (DMSO), dimethylacetamide, and N,N-dimethylformamide.

10. 10. The method of any one of claims 1 to 9, wherein applying ultrasonic vibrations to the first suspension comprises applying ultrasonic energy in the range of about 10 W to about 100 kW per kg of the first suspension, or in the range of about 50 W to about 1000 W per kg of the first suspension, or in the range of about 100 W to about 500 W per kg of the first suspension, or in the range of about 1 kW to about 5 kW per kg of the first suspension, or in the range of about 5 kW to about 10 kW per kg of the first suspension, or in the range of 10 kW to about 50 kW per kg of the first suspension, or in the range of about 50 kW to about 100 kW per kg of the first suspension.

11. 11. The method of any one of claims 1 to 10, further comprising heating and / or maintaining the temperature of the first suspension in the range of about 10°C to about 100°C.

12. 12. The method of claim 11, wherein maintaining the temperature of the first suspension is for a duration that ultrasonic vibrations are applied.

13. 13. The method of any one of claims 1 to 12, wherein isolating the metal flakes, the binder material and the black mass comprises passing the first suspension sequentially through one or more sieves of different sizes.

14. 14. The method of claim 13, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

15. 15. The method of claim 14, further comprising passing the first suspension through a sieve having a smallest mesh size and then drying any remaining undissolved material to obtain graphite powder.

16. 16. The method of any one of claims 1 to 15, wherein the remaining material of the portion of the used lithium ion battery comprises fragments of one or more of plastic, metal separator, polymer separator, and electrolyte.

17. 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; a first separator configured to separate the pieces of the used lithium ion battery into electrode pieces and material remnants, the electrode pieces including black mass, metal pieces, and binder material; and one or more heating chambers configured to heat the electrode strips to a predetermined temperature for a predetermined period of time; an ultrasonic treatment chamber coupled to an ultrasonic generator, the ultrasonic treatment chamber configured to apply ultrasonic vibrations generated by the ultrasonic generator to a first suspension of preheated electrode pieces in a neutral liquid; a second separator configured to separate the metal pieces, the binder material, and the black mass; a controller for controlling the temperature within the one or more heating chambers; and a controller configured to control an ultrasonic generator coupled to the sonication chamber to control the application of the ultrasonic vibrations; A system comprising:

18. 20. The system of claim 17, further comprising a mixing chamber configured to mix preheated electrode pieces with the neutral liquid to obtain the first suspension.

19. 19. The system of claim 17 or 18, wherein the controller is configured to control the frequency and intensity of ultrasonic vibrations applied to the sonication chamber and to control the amount of time the ultrasonic vibrations are applied.

20. The system of any one of claims 17 to 19, wherein the one or more heating chambers are configured to be maintained under vacuum and / or to have an inert atmosphere.

21. The system of any one of claims 17 to 20, wherein the grinder is configured to be maintained under vacuum and / or to have an inert atmosphere.

22. The system of any one of claims 17 to 21, wherein the predetermined temperature is in the range of about 200°C to about 350°C.

23. The system of any one of claims 17 to 22, wherein the predetermined period of time is in the range of 30 minutes to about 120 minutes.

24. The system of any one of claims 17 to 23, wherein the ultrasonic vibrations have a frequency in the range of about 25 kHz to about 100 kHz.

25. 25. The system of any one of claims 17 to 24, wherein the ultrasonic vibrations are applied to the first suspension for a period of time in the range of about 10 minutes to about 100 minutes.

26. 26. The system of any one of claims 17 to 25, wherein the ultrasonic vibrations have an energy in the range of about 10 W to about 100 kW per kg of the first suspension, or in the range of about 50 W to about 1000 W per kg of the first suspension, or in the range of about 100 W to about 500 W per kg of the first suspension, or in the range of about 1 kW to about 5 kW per kg of the first suspension, or in the range of about 5 kW to about 10 kW per kg of the first suspension, or in the range of 10 kW to about 50 kW per kg of the first suspension, or in the range of about 50 kW to about 100 kW per kg of the first suspension.

27. 27. The system of any one of claims 17 to 26, further comprising a heater coupled to the sonication chamber, the heater configured to raise and / or maintain a temperature of the first suspension at a temperature in a range of about 10°C to about 100°C.

28. 28. The system of claim 27, wherein the temperature of the first suspension is maintained for a period of time in a range from about 10 minutes to about 100 minutes.

29. 29. The system of any one of claims 17 to 28, wherein the second separator is configured to separate the metal pieces, the binder material, and the black mass by sequentially passing the first suspension through one or more sieves of different sizes.

30. 30. The system of claim 29, wherein the one or more sieves have a mesh size in the range of about 5 mm to about 0.01 mm.

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