Battery shreds, battery disposal method, and battery disposal system

Abstract

The present invention relates to battery shreds, a battery disposal method and a waste battery disposal system. The battery shreds comprise cathodes and anodes, and comprise copper, wherein at least a portion of the copper is disposed on the anodes, the copper disposed on the anodes is circular or elliptical, and the proportion of the copper is 4.3% or less on the basis of 100% of the anodes.

Description

Battery shreds, battery processing method, and battery processing system

[0001] The present invention relates to waste battery recycling, and more specifically to battery shreds generated from waste battery recycling, a battery processing method, and a battery processing system.

[0002] The present invention claims priority based on Korean Patent Application No. 10-2024-0154388 filed on November 4, 2024, the entire contents of said application incorporated herein by reference.

[0003] Battery demand is rapidly increasing as they are widely used not only in electronic devices such as smartphones and mobile devices but also in electric vehicles. The demand for these batteries is expected to rise further as the demand for electric vehicles increases as the next-generation mode of transportation.

[0004] Since the aforementioned electric vehicle requires a battery with a large electrical capacity, it is installed and used in the vehicle in units of multiple battery cells, modules composed of multiple battery cells, and packs composed of multiple modules. As the usage of the electric vehicle increases rapidly, the amount of waste generated from batteries used in the electric vehicle is also increasing.

[0005] Recently, the issue of disposing of lithium-ion batteries, such as waste electric vehicle batteries, has emerged globally. These lithium-ion batteries pose fire hazards due to organic solvents and contain explosive substances as well as heavy metals such as Ni, Co, Mn, and Fe. Among these, Ni, Co, Mn, and Li are valuable metals with scarcity and utility value; therefore, the recovery and recycling processes following the disposal of these lithium-ion batteries have become critical issues.

[0006] The first step in the lithium-ion battery recycling process is to produce black powder or black alloy, which are intermediate products fed into the subsequent wet treatment process. At this time, pretreatment is very important to minimize chemical energy reactions in order to safely crush the lithium-ion battery. Various methods such as salt discharge, electric discharge, or cryogenic treatment are utilized as pretreatment methods, and can be broadly divided into dry treatment methods and wet treatment methods.

[0007] In the case of salt discharge, which is a representative example of the above wet treatment method, it is a treatment method that uses salt water with a solvent such as sodium chloride, has a low risk of fire, and is easy to access in the early stages of development due to the low difficulty of technology development. However, in the case of the above salt discharge, there is a problem of wastewater generation and contamination by the solvent.

[0008] Electric discharge methods, which are representative examples of the above dry processing methods, include reversible discharge, which is discharge condition up to the standard reduction potential within the battery, and irreversible discharge, which is discharge below the standard reduction potential. Generally, the standard reduction potential of the positive and negative electrodes of a typical ternary NCM battery is about 2.5 V. When an irreversible discharge is performed at a value of 2.5 V or lower, there is a problem in that the SEI layer on the surface of the negative electrode material decomposes, causing the battery's performance characteristics to deteriorate.

[0009] At this time, the electrolysis of the copper (Cu) current collector is determined by the speed of the electric discharge. In the case of the electric discharge mentioned above, there are resistance discharge, which discharges by allowing electricity to flow through the positive and negative electrodes using electrically conductive materials, and potential difference discharge, which forces electrons to flow by applying a larger potential difference between the positive and negative electrodes. Specifically, in potential difference discharge, a 220 to 440 V power source is lowered through a transformer using a discharger, and this voltage is higher than that of the battery. At this time, the magnitude of the voltage may be controlled to fix the current, or conversely, the voltage may be fixed while varying the current. The discharger supplies current at a voltage higher than that of the battery; at this time, the discharger supplies a relatively high voltage along with the battery's current, causing the battery to discharge. Thus, the principle of potential difference discharge is to discharge by utilizing the potential difference between the discharger and the battery.

[0010] The above resistance discharge is a method of continuously lowering the potential difference so that the voltage within the battery becomes 0 V when there is residual voltage within the battery. At this time, if a resistor, such as a resistor, is connected, the voltage within the battery may be removed by resistance heat. Although the above resistance discharge does not cause electrolysis of the copper current collector due to its slow discharge rate, it has the problem of requiring a very long processing time. Since the above potential difference discharge forcibly flows electrons from the negative electrode to the positive electrode, positively charged lithium ions also flow forcibly, and subsequently, electrolysis occurs as the reduction potential value of copper is exceeded. As such, active research is currently underway regarding the electrolysis of copper caused by a negative potential difference during electric discharge.

[0011] However, there is a problem in that copper is introduced into the black mass during the electric discharge process, which reduces the copper recovery rate and causes contamination issues related to copper content in the recovery processes of nickel, cobalt, and manganese.

[0012] The technical problem that the present invention aims to solve is to provide battery crushed material that has a low penetration rate and low copper contamination resulting from the electrolysis of copper, thereby increasing the recovery rate of valuable metals when applied to subsequent processes.

[0013] Another technical problem that the present invention aims to solve is to provide a method for treating a battery that reduces the penetration rate resulting from the electrolysis of copper and reduces copper contamination within the black mass.

[0014] Another technical problem that the present invention aims to solve is to provide a battery processing system having the aforementioned advantages.

[0015] According to one embodiment of the present invention, the battery crushed material comprises a positive electrode and a negative electrode, and comprises copper, wherein at least a portion of the copper is disposed on the negative electrode, and the shape of the copper disposed on the negative electrode may have a circular or elliptical shape, and the ratio of the copper disposed on the negative electrode may be 4.3% or less based on 100% of the negative electrode. In one embodiment, the copper may be leached and disposed on the negative electrode.

[0016] In one embodiment, the proportion of copper disposed on the cathode may be 4.0% or less based on 100% of the cathode. In one embodiment, the average particle size (D50) of the copper may be 1 to 7 μm.

[0017] A method for processing a battery according to another embodiment of the present invention relates to a method for processing a waste battery satisfying a first voltage, which is a cell unit voltage of a predetermined range, to produce black mass, and may include a first electric discharge step of electrically discharging the waste battery, a second electric discharge step of electrically discharging the waste battery satisfying a second voltage lower than the first voltage, and a step of crushing the waste battery. In one embodiment, the first electric discharge step may be performed at a rate of voltage decrease per hour based on the cell in the range of 0.1 to 2.5 V / h.

[0018] In one embodiment, the second electric discharge step may be a step of preventing voltage recovery of the waste battery that has undergone the first electric discharge step. In one embodiment, the first voltage may be greater than 0.5 V.

[0019] In one embodiment, the second voltage may be 0.5 V or less. In one embodiment, the second electric discharge step may use a resistive object having a resistance value higher than copper.

[0020] In one embodiment, the resistance value may be 1.68 * 10⁻⁸ ohm-m or greater. In one embodiment, the second electric discharge step may perform a resistance discharge. In one embodiment, the step of crushing the waste battery may crush the waste battery discharged to 1.0 V or less relative to the cell.

[0021] In one embodiment, the waste battery that has undergone the second electric discharge step may include a step of atmospheric treatment, and the atmospheric treatment step may be performed for 3 hours or more. In one embodiment, the method may include a step of classifying the battery shreds generated from the step of shredding the waste battery.

[0022] In one embodiment, a step of drying the battery shreds generated from the step of shredding the waste battery at 150°C or lower may be performed. In one embodiment, the proportion of copper in the battery shreds generated from the step of shredding the waste battery may be 4.0% or less based on 100% of the negative electrode. In one embodiment, the copper may have a circular or elliptical shape.

[0023] According to another embodiment of the present invention, a battery processing system relates to a waste battery processing system that processes a waste battery satisfying a first voltage, which is a cell unit voltage of a predetermined range, to produce black mass, and may include a first discharge unit that electrically discharges a waste battery having the first voltage, a second discharge unit that electrically discharges the waste battery satisfying a second voltage lower than the first voltage, and a waste battery crushing unit that crushes the waste battery. In one embodiment, the first voltage may be greater than 0.5 V.

[0024] In one embodiment, the first discharge unit may discharge the waste battery in the range of 0.1 to 2.5 V / h. In one embodiment, the second voltage may be 0.5 V or less. In one embodiment, the second discharge unit may discharge the waste battery using a resistive object having a resistance value higher than copper.

[0025] According to one embodiment of the present invention, battery crushed material provides black mass that minimizes copper, thereby increasing the recovery rate of valuable metals in subsequent processes.

[0026] According to another embodiment of the present invention, a battery treatment method comprises a plurality of electric discharges to reduce the penetration rate of copper electrolysis and reduce copper contamination in black mass.

[0027] According to another embodiment of the present invention, a battery processing system comprises a plurality of discharge units, thereby providing a system that reduces the penetration rate resulting from the electrolysis of copper and reduces copper contamination within the black mass.

[0028] Figure 1 is an SEM image showing the copper ratio on the surface of the negative electrode material in the battery crushed material according to one embodiment of the present invention.

[0029] Figure 2 is an SEM image showing the copper ratio on the surface of the negative electrode material in the battery crushed material according to a comparative example of the present invention.

[0030] Figure 3 shows the voltage rise according to the waiting time in the second electric discharge step according to one embodiment of the present invention.

[0031] FIG. 4 is an SEM image of a battery crushed material according to one embodiment of the present invention.

[0032] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0033] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0034] When it is stated that one part is "above" or "on" another part, it may be directly above or on the other part, or other parts may be involved in between. In contrast, when it is stated that one part is "directly above" another part, no other parts are interposed in between.

[0035] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0036] According to one embodiment of the present invention, the battery shredder is intended for recovering valuable metals from waste batteries and may have a layered structure in which the positive electrode and the negative electrode include a separator on at least one surface. The layered structure may be configured such that the positive electrode and the negative electrode are included on one or both surfaces of the separator based on the separator.

[0037] The above layered structure may include, for example, an anode-separator-cathode, a cathode-separator-anode, a separator-cathode, or a cathode-separator. As the layered structure is stacked in at least one layer, the battery fragment may have a predetermined thickness in the thickness direction. In this case, the number of layers of the layered structure may correspond to the number of separators.

[0038] In one embodiment, copper may be disposed within the negative electrode of the battery fragment. Specifically, the copper may be derived from a copper foil serving as a current collector. More specifically, the copper may be deposited on the negative electrode after being electrolyzed during an electric discharge process.

[0039] In one embodiment, the copper may be formed at the cathode. Specifically, the copper may be formed by electrolytic leaching into the electrolyte and then electrodepositing it on the anode. In this way, the copper placed at the cathode may be formed by electrolysis during a plurality of electric discharge processes described later.

[0040] In one embodiment, the proportion of copper disposed on the cathode may be 4% or less based on 100% of the total cathode. Specifically, the proportion of copper refers to the ratio of the area of ​​copper in the SEM image based on 100% of the total cathode. Specifically, the copper proportion may be 4.0% or less, more specifically 0.05 to 2.0% or less, even more specifically 0.05 to 1.2%, and even more specifically 0.05 to 0.1% or less. Satisfying the aforementioned range of the copper area corresponds to having a low copper content in the cathode, and by satisfying the aforementioned range of the copper area, the proportion of copper in the battery crushed material, specifically the black mass, can be kept low, and the burden of impurities in the subsequent process can be reduced.

[0041] If the area of ​​the copper exceeds the upper limit of the aforementioned area, it indicates that the electric discharge was performed excessively rapidly, leading to the excessive formation of contaminants and potentially increasing the burden of impurities in subsequent processes. If the area of ​​the copper exceeds the lower limit of the aforementioned area, excessive energy is consumed to remove the copper during the pretreatment process, resulting in a lack of economic feasibility.

[0042] In one embodiment, the shape of the copper disposed on the cathode may have a circular or elliptical shape. Specifically, the shape of the copper may maintain a shape formed on the cathode. More specifically, the copper may be applied to at least a portion of the surface of the cathode and maintain a state formed on the cathode.

[0043] The shape of the copper described above may be formed by the copper being leached into the electrolyte from the cathode during the multiple electric discharge processes described later, undergoing electrolysis, and then being electrodeposited onto the anode. In contrast, the copper current collector incorporated during the crushing process may have a rectangular shape, such as a plate shape. Thus, the shape of the copper may be a characteristic manifested at the cathode within the battery crush material by undergoing multiple electric discharges.

[0044] In one embodiment, the average particle size (D50) of the copper may be 1 to 7 μm. Specifically, the average particle size may be 2 to 5 μm, and more specifically, 2 to 4 μm. The average particle size may refer to the particle size distribution of the copper, specifically the particle size corresponding to 50% of the volume distribution based on the cumulative percentage. By satisfying the aforementioned range, the average particle size of the copper has the advantage of being easy to remove as an impurity in a subsequent process.

[0045] If the average particle size of the copper exceeds the upper limit of the aforementioned range, the large surface area occupied by copper on the cathode surface leads to problems such as excessive energy consumption for copper removal in subsequent processes and a decrease in the recovery rate of valuable metals. If the average particle size of the copper exceeds the lower limit of the aforementioned range, there is a problem such as excessive energy consumption for copper removal in the pretreatment process.

[0046] A battery processing method according to another embodiment of the present invention comprises a first electric discharge step of electrically discharging a waste battery having a first voltage, a second electric discharge step of electrically discharging the waste battery satisfying a second voltage lower than the first voltage, and a step of crushing the waste battery. Specifically, the battery processing method of the present invention may relate to a waste battery processing method for processing a waste battery to produce a battery crushed material, specifically, black mass.

[0047] The above-mentioned waste battery may refer to a battery that is difficult to use, including a battery that has reached the end of its lifespan or a cell that has been partially short-circuited. Specifically, the above-mentioned waste battery may include a plurality of cells, a module containing a plurality of cells, or a pack containing a plurality of modules. More specifically, the above-mentioned waste battery may refer to a state in which electrolyte has been injected.

[0048] In one embodiment, the first voltage may be greater than 0.5 V. Specifically, the first voltage may mean a voltage greater than 0.5 V, more specifically, greater than 1.0 V. Since the waste battery has the first voltage and carries chemical energy itself, there is a problem that it may increase the possibility of fire occurring in a subsequent process.

[0049] In one embodiment, the waste battery may be a battery having a reversible discharge range of about 2.5 V. Specifically, the waste battery is determined by the standard reduction potential difference between the positive and negative electrodes within the waste battery, and the reversible range may be based on the state in which an electrolyte is injected into the positive electrode, the negative electrode, and the separator.

[0050] In one embodiment, the first electric discharge step may be a step of electrically discharging the waste battery. Specifically, the electric discharge step may be a pretreatment step that minimizes chemical energy reactions within the waste battery before crushing the waste battery. More specifically, the first electric discharge step may be a pretreatment step that prevents safety issues, such as fire, from occurring due to external impacts applied during subsequent processes, such as dismantling and crushing of the waste battery.

[0051] The above-mentioned electric discharge step may involve performing a reversible discharge, which is a discharge condition up to the standard reduction potential within the waste battery, or an irreversible discharge, which is a discharge below the standard reduction potential. More specifically, the above-mentioned electric discharge step may be an irreversible discharge.

[0052] In one embodiment, the first electric discharge step may be performed in the range of 0.1 to 2.5 V / h. The first electric discharge step may be performed at a rate of voltage decrease per hour relative to the cell in the range of 0.1 to 2.5 V / h. Specifically, the first electric discharge step may be in the range of 0.5 to 1.5 V. By satisfying the aforementioned range, the first electric discharge step can minimize chemical energy reactions within the waste battery and prevent excessive leaching of copper to the negative electrode during electrolysis.

[0053] If the above range exceeds the upper limit of the aforementioned range, there is a problem where the amount of copper electrodeposited increases or the battery explodes due to swelling. If the above range exceeds the lower limit of the aforementioned range, the time required for discharge increases, resulting in poor economic efficiency.

[0054] The second electric discharge step may be a step of discharging the waste battery satisfying a second voltage lower than the first voltage. Specifically, when the waste battery, whose voltage has been lowered by the first electric discharge, reaches a second voltage satisfying a predetermined range, the process may be switched to the second electric discharge and the electric discharge may be performed. More specifically, the second electric discharge step may be a step of preventing the voltage recovery of the waste battery that has undergone the first electric discharge step. By including the second electric discharge step, the discharged waste battery is prevented from recovering its voltage, thereby allowing the process to be performed more safely in subsequent processes.

[0055] In one embodiment, the second voltage may be 0.5 V or less. Specifically, when the voltage of the waste battery reaches 0.5 V or less after passing through the first electric discharge step, a second electric discharge step may be performed to prevent the voltage from recovering.

[0056] The second electric discharge step may be a step of discharging by using an electrically conductive material to facilitate the flow of current between the positive and negative electrodes. Specifically, the second electric discharge step may be a step of allowing current to continuously flow between the positive and negative electrodes within the battery using the electrically conductive material so that the battery discharges itself. More specifically, the second electric discharge step may be a step of performing a resistance discharge.

[0057] In one embodiment, the second electric discharge step may utilize a resistive object having a resistance value higher than that of copper. Specifically, by utilizing the aforementioned resistive object, the second electric discharge step can prevent the copper current collector within the waste battery from being electrolyzed.

[0058]

[0059] *In the 54-day embodiment, the second electric discharge step has a resistance value of 1.68 * 10 -8 It may be possible to use a resistance object with a resistance of ohm-m or greater. By using a resistance object having the aforementioned resistance value in the second electric discharge step, the copper current collector in the waste battery may be electrolyzed and the voltage of the waste battery may be prevented from recovering.

[0060] In one embodiment, the second electric discharge step may include a step of air-treating the waste battery. Specifically, the air-treating step was performed for 3 hours or more, specifically, for 3 to 10 hours. By performing the second electric discharge step in the aforementioned range, voltage recovery of the waste battery is prevented, and the battery can be safely shredded in a subsequent process.

[0061] If the second electric discharge step exceeds the upper limit of the aforementioned range, voltage recovery occurs, sparks are generated during the battery crushing process, and the process processing time is excessively long. If the second electric discharge step exceeds the lower limit of the aforementioned range, voltage recovery occurs.

[0062] As such, in order to safely shred waste batteries, it is necessary to properly maintain the safe voltage of the batteries and the standby processing stage.

[0063] In one embodiment, the step of crushing the waste battery may include crushing the waste battery by applying physical or mechanical force to the waste battery and crushing it into a fine powder.

[0064] In one embodiment, the step of crushing the waste battery may be a crushing method using at least one of shearing, compression, and tensile force. Specifically, the crushing step may be performed by, for example, at least one of a hammer mill, a ball mill, and a stirred ball mill. The hammer mill may perform at least one step of disassembly, punching, and milling, and various types of crushing or grinding devices, such as industrial grinders, may be utilized as non-limiting examples. The step of crushing the battery may separate some large impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastic, from the composition contained in the battery.

[0065] In one embodiment, the step of crushing the waste battery may be performed such that the size of the battery crushed material is 100 mm or less. Specifically, the size of the battery crushed material may be 80 mm or less, more specifically, 50 mm or less. When the size of the battery crushed material satisfies the aforementioned range, there is an advantage of excellent process energy efficiency, and when the size of the battery crushed material is larger than the aforementioned range, there is an uneconomical problem due to excessive energy supply during the heat treatment step.

[0066] In one embodiment, the step of crushing the waste battery may be a step of crushing the waste battery that has been discharged to 1 V or less based on the cell. Specifically, the step of crushing the waste battery may be a step of crushing the waste battery having a voltage within a predetermined range after undergoing an electric discharge step of the waste battery. By crushing the waste battery after discharging it to the aforementioned range, the possibility of fire occurrence can be reduced.

[0067] In one embodiment, the method may include a step of classifying the battery shreds generated from the step of shredding the waste battery. The step of classifying the battery shreds may include a step of obtaining a product of about 100 μm or less by using a sieve with a range of 80 to 120 μm, specifically a sieve with a range of 90 to 110 μm, on the battery shreds. Specifically, the product recovered through the classifying step may refer to black mass.

[0068] In one embodiment, a step of drying the battery shreds generated from the step of shredding the waste battery may be performed. Specifically, the drying step may be performed on the battery shreds at 150°C or lower. The step of drying the battery shreds may be a process of removing the electrolyte from the battery shreds. As the step of drying the battery shreds is performed within the aforementioned range, the possibility of fire caused by residual voltage in the waste battery can be minimized.

[0069] According to another embodiment of the present invention, a battery processing system comprises a first discharge unit for electrically discharging a waste battery having a first voltage, a second discharge unit for electrically discharging the waste battery satisfying a second voltage lower than the first voltage, and a waste battery crushing unit for crushing the waste battery. Specifically, the battery processing system of the present invention may control and process the voltage of the waste battery in the first discharge unit and the second discharge unit to produce a battery crushed material, specifically, black mass.

[0070] In one embodiment, the waste battery may have a first voltage. Specifically, the first voltage may be controlled to a voltage greater than 0.5 V, more specifically, greater than 1.0 V. Since the waste battery is controlled to the first voltage and carries chemical energy itself, there is a problem that it may increase the possibility of fire occurring in a subsequent process.

[0071] In one embodiment, the first discharge unit may electrically discharge the waste battery. Specifically, the first discharge unit may be a pretreatment step that minimizes chemical energy reactions within the waste battery before crushing the waste battery. More specifically, the first discharge unit may be a pretreatment unit that prevents safety issues, such as fire, caused by external impacts applied during subsequent processes, such as dismantling and crushing of the waste battery.

[0072] The first discharge unit may perform a reversible discharge, which is a discharge condition up to the standard reduction potential within the waste battery, or an irreversible discharge, which is a discharge below the standard reduction potential. More specifically, the first discharge unit may be an irreversible discharge.

[0073] In one embodiment, the first discharge unit may be performed in a range of 0.1 to 2.5 V / h. The first discharge unit may be performed at a rate of voltage decrease per hour relative to the cell in a range of 0.1 to 2.5 V / h. Specifically, the first discharge unit may be in a range of 0.5 to 1.5 V. As the first discharge unit performs electrical discharge within the aforementioned range, the chemical energy reaction within the waste battery can be minimized, and excessive leaching of copper to the negative electrode during electrolysis can be prevented.

[0074] If the above range exceeds the upper limit of the aforementioned range, there is a problem where the amount of copper electrodeposited increases or the battery explodes due to swelling. If the above range exceeds the lower limit of the aforementioned range, the time required for discharge increases, resulting in poor economic efficiency.

[0075] The second discharge unit described above can discharge the waste battery satisfying a second voltage lower than the first voltage. Specifically, when the voltage of the waste battery, which has been lowered by the first discharge unit, reaches a second voltage satisfying a predetermined range, it may be switched by the second discharge unit to perform an electric discharge. More specifically, the second discharge unit can prevent the voltage of the waste battery that has passed through the first discharge unit from recovering. By including the second discharge unit, the voltage of the electrically discharged waste battery is prevented from recovering, thereby allowing the process to be performed more safely in subsequent processes.

[0076] In one embodiment, the second voltage may be 0.5 V or less. Specifically, when the voltage of the waste battery reaches 0.5 V or less after passing through the first discharge unit, the second discharge unit may be operated to prevent the voltage from recovering.

[0077] The second discharge unit may be a step of discharging by using an electrically conductive material to facilitate the flow of current between the positive and negative electrodes. Specifically, the second discharge unit may be a step of allowing current to continuously flow between the positive and negative electrodes within the battery using the electrically conductive material so that the battery discharges itself. More specifically, the second discharge unit may perform a resistance discharge.

[0078] In one embodiment, the second discharge unit may use a resistive object having a resistance value higher than copper. Specifically, by using the aforementioned resistive object, the second discharge unit can prevent the copper current collector in the waste battery from being electrolyzed.

[0079] In one embodiment, the second discharge part has a resistance value of 1.68 * 10 -8 It may use a resistance object with a resistance of ohm-m or higher. By using a resistance object having the aforementioned resistance value, the second discharge unit can prevent the copper current collector in the waste battery from being electrolyzed and prevent the voltage of the waste battery from recovering.

[0080] In one embodiment, the second discharge unit may perform ambient treatment on the waste battery. Specifically, the second discharge unit may be controlled to perform ambient treatment on the waste battery for 3 hours or more, specifically, for 3 to 10 hours. By performing ambient treatment on the waste battery within the aforementioned range, the second discharge unit prevents voltage recovery of the waste battery and can safely shred the battery in a subsequent process.

[0081] When the second discharge unit exceeds the upper limit of the aforementioned range, voltage recovery occurs, sparks are generated during the battery crushing process, and the process processing time is excessively long. When the second discharge unit exceeds the lower limit of the aforementioned range, voltage recovery occurs.

[0082] As such, in order to safely shred waste batteries, it is necessary to properly maintain the safe voltage of the batteries and the standby processing stage.

[0083] In one embodiment, the crushing unit may crush the waste battery by applying physical or mechanical force to the waste battery and crush it into a fine powder. In one embodiment, the crushing unit may crush the waste battery using at least one of shear, compression, and tensile force. Specifically, the crushing unit may be performed by, for example, at least one of a hammer mill, a ball mill, and a stirred ball mill. The hammer mill may be performed by at least one of disassembly, punching, and milling, and various types of crushing or grinding devices, such as industrial grinders, may be utilized as non-limiting examples. The crushing unit may separate some large impurities, such as aluminum (Al), copper (Cu), iron (Fe), and plastic, from the composition contained in the battery.

[0084] In one embodiment, the crushing unit may be performed such that the size of the battery crushed material is 100 mm or less. Specifically, the size of the battery crushed material may be 80 mm or less, more specifically, 50 mm or less. When the size of the battery crushed material satisfies the aforementioned range, there is an advantage of excellent process energy efficiency, and when the size of the battery crushed material is larger than the aforementioned range, there is an uneconomical problem due to excessive energy supply during the heat treatment step.

[0085] In one embodiment, the crushing unit may crush the waste battery discharged to 1 V or less based on the cell. Specifically, the step of crushing the waste battery may crush the waste battery having a voltage within a predetermined range after electric discharge is performed. By crushing the waste battery after discharging it to the aforementioned range, the possibility of fire occurrence can be reduced.

[0086] In one embodiment, the apparatus may include a classifier for classifying battery crushed material generated from the crushing unit. The classifier may obtain a product of about 100 μm or less by using a sieve with a range of 80 to 120 μm, specifically a sieve with a range of 90 to 110 μm, on the battery crushed material. Specifically, the product recovered through the classifier may refer to black mass.

[0087] In one embodiment, a drying unit may be included for drying the battery shreds generated from the crushing unit. Specifically, the drying unit may dry the battery shreds at 150°C or lower. The drying unit may remove the electrolyte within the battery shreds. As the drying step is performed within the aforementioned range, the drying unit may minimize the possibility of fire caused by residual voltage in the waste battery.

[0088]

[0089] Preferred embodiments and comparative examples of the present invention are described below. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0090]

[0091] <Experimental Example 1>: Whether resistance discharge is included

[0092] <Example 1>

[0093] (Step for preparing waste batteries)

[0094] The step of preparing the waste battery involved preparing a waste battery containing an NCM 622 positive electrode and having an electrolyte injected. At this time, the irreversible discharge range of the waste battery is characterized by being approximately 2.5 V for NCM and 2.7 V for LFP. This is based on the state in which an electrolyte is injected into the positive electrode, the negative electrode, and the separator.

[0095]

[0096] (Step of performing the first electric discharge)

[0097] The above waste battery was subjected to electric discharge at 1.5 V / hr-cell. Specifically, based on cell units, the above waste battery was subjected to a first electric discharge at the aforementioned discharge rate from a charged state to a voltage value within the reversible discharge range. At this time, in the first electric discharge, the charging was 3.1 V, and the discharging was performed down to 0.1 V.

[0098]

[0099] (Step of performing the second electric discharge)

[0100] After performing the first electric discharge, a second electric discharge was performed to prevent voltage recovery. This was performed using a resistive object while the voltage of the cell unit was 0.5 V or lower. Additionally, the second electric discharge was performed while standing for 3 hours. At this time, the resistive object used copper with a resistance of 1.68 * 10⁻⁸ ohm-m (20°) or higher, and the second electric discharge is characterized by this.

[0101]

[0102] (Step of crushing waste batteries)

[0103] The waste battery was shredded using a 2-axis 2-stage shredder to a size of 100 mm or less to form shredded battery material. At this time, the size of the shredded battery material refers to the length based on the major axis among the width, length, and height of the shredded battery material. At this time, the step of shredding the waste battery was performed within 3 hours after the discharge of the waste battery.

[0104]

[0105] (Step of drying battery crushed material)

[0106] A drying step was performed on the battery crushed material at a temperature of approximately 150°C to remove the electrolyte. By undergoing the drying step, the possibility of fire caused by residual voltage in the crushed material was minimized.

[0107]

[0108] (Step of separating the particle size of the above battery crushed material)

[0109] The battery crushed material that underwent the drying step was separated by particle size based on a particle size of 100 μm, and copper and aluminum originating from the current collector, which are larger than 100 μm, were removed.

[0110]

[0111] <Comparative Example 1>

[0112] The procedure was performed in the same manner as Example 1, except that the step of performing a second electric discharge of the waste battery was not taken.

[0113]

[0114] Table 1 below shows whether swelling occurred in the waste battery according to Example 1 and Comparative Example 1, the maximum temperature, and the ratio of copper placed on the surface of the negative electrode material within the battery crush. The maximum temperature and the ratio of copper were measured by the following method.

[0115] Swelling occurrence: After electrically discharging the waste battery, if the waste battery swells by 3 mm or more using a vernier caliper device, it is marked as O, and if the waste battery maintains a thickness lower than 3 mm, it is marked as X.

[0116] Maximum temperature of waste battery: The average temperature of the waste battery that has undergone electrical discharge was measured using a thermal imaging camera.

[0117] Copper ratio: The copper ratio is the percentage of the area occupied by two or more points relative to 100% of the total area of ​​the negative electrode, using the EDS component in SEM on the surface of the negative electrode material within the waste battery shredder that has undergone electric discharge and battery shredding processes.

[0118] Whether swelling occurs Maximum temperature [°C] Cu [%] Cu shape Cu shape Drawing Example 1 X 38 1.2 Circularity 1 Comparative Example 1 O 60 4.4 Circularity 2

[0119]

[0120] Looking at Table 1 above, it can be confirmed that Example 1, which underwent the first and second electric discharges as in the present invention, does not exhibit swelling, and that after the electric discharge, the maximum temperature of the waste battery is approximately 38°C, indicating a low probability of fire when applied to the crushing stage. Additionally, it can be confirmed that the copper ratio of the negative electrode material in the crushed battery material after the waste battery crushing stage is low at 1.2%, indicating that the electrolysis of impurities such as copper has been minimized. In contrast, in the case of Comparative Example 1, which did not include the second electric discharge, swelling of the waste battery occurred, and the maximum temperature was high, indicating a high probability of fire when applied to the crushing stage. Furthermore, it can be confirmed that the copper ratio of the negative electrode material in the crushed battery material after the waste battery crushing stage is high, indicating that impurities such as copper have been electrolyzed and leached into the crushed material. If impurities such as copper leach into the crushed material, the copper contamination is high when obtaining black mass, which may require a subsequent process to additionally remove copper, and there is a problem of a low recovery rate of the obtained valuable metal.

[0121] <Experimental Example 2> - Discharge Rate Control

[0122] <Example 2>

[0123] The procedure was performed in the same manner as Example 1, except that the discharge rate in the first electric discharge was controlled to 1.0 V / hr.

[0124]

[0125] <Example 3>

[0126] The procedure was performed in the same manner as Example 1, except that the discharge rate in the first electric discharge was controlled to 0.5 V / hr.

[0127]

[0128] <Comparative Example 2>

[0129] The procedure was performed in the same manner as Example 1, except that the discharge rate in the first electric discharge was controlled to 3.0 V / hr.

[0130]

[0131] <Comparative Example 3>

[0132] The procedure was performed in the same manner as Example 1, except that the discharge rate in the first electric discharge was controlled to 5.0 V / hr.

[0133]

[0134] <Comparative Example 4>

[0135] The procedure was performed in the same manner as Example 1, except that the discharge rate in the first electric discharge was controlled to 7.0 V / hr.

[0136]

[0137] Table 2 below shows whether swelling of the waste battery occurs, the maximum temperature, and the copper ratio of the negative electrode material in the battery crushed material when the discharge rate is controlled in the first electric discharge according to the embodiments and comparative examples of the present invention.

[0138] Discharge rate of the first electric discharge stage [V / hr] Whether swelling occurs Maximum temperature [°C] Cu [%] Example 1 1.5 x 38 1.2 Example 2 1.0 x 35 0.1 Example 3 0.5 x 30 0.05 Comparative Example 1 30 40 4.1 Comparative Example 2 50 50 12.2 Comparative Example 3 70 70 14.1

[0139]

[0140] Looking at Table 2 above, it was confirmed that the discharge rate satisfies the range of the present invention, so swelling of the waste battery does not occur, and the maximum battery temperature is lower than 40°C. In addition, it was confirmed that the copper content of the negative electrode material in the battery crushed material is low, at 1.5% or less. On the other hand, it was confirmed that when the discharge rate is performed at a rate higher than 1.5 V, swelling of the waste battery occurs, and the maximum temperature is high, so there is a high possibility of fire when applied to the crushing stage. In addition, it was confirmed that the copper content of the negative electrode material in the battery crushed material after the waste battery crushing stage is high, indicating that impurities such as copper are electrolyzed and leached into the crushed material. When impurities such as copper are leached into the crushed material, copper contamination is high when obtaining black mass, which may require a process to additionally remove copper in subsequent processes, and there is a problem of a low recovery rate of the obtained valuable metal.

[0141] Copper Ratio According to Discharge Rate

[0142] Figure 1 is an SEM image showing the copper ratio on the surface of the negative electrode material in the battery crushed material according to one embodiment of the present invention.

[0143] Figure 2 is an SEM image showing the copper ratio on the surface of the negative electrode material in the battery crushed material according to a comparative example of the present invention.

[0144] Figure 1 shows the copper ratio on the surface of the negative electrode material of a battery crushed material according to Example 2, and Figure 2 shows the copper ratio on the surface of the negative electrode material of a battery crushed material according to Comparative Example 2. Specifically, referring to Figures 1 and 2, it can be seen that when the discharge rate falls within the range of the present invention, the copper ratio on the surface of the negative electrode material is low, and when the electric discharge is performed at a discharge rate higher than that of the present invention, the degree of copper contamination is high.

[0145] Figure 3 shows the voltage rise according to the waiting time in the second electric discharge step according to one embodiment of the present invention.

[0146] Referring to Fig. 3, the process of the voltage of the waste battery recovering after the first electric discharge and the second electric discharge is shown. It was confirmed that when the waiting time exceeds 10 hours, the voltage of the waste battery increases by 1.0 V.

[0147] FIG. 4 is an SEM image of a battery crushed material according to one embodiment of the present invention.

[0148] Figure 4 is an SEM image of a battery fragment according to an embodiment of the present invention. Specifically, referring to Figure 4, when a discharge is performed through electric discharge, a voltage difference of +0.34 V or higher, which is the standard reduction potential of copper, is generated, and electrolysis is performed. Accordingly, the copper is re-electrodeposited at the anode, and the shape of the copper is formed into a circular shape, unlike the angular shape which is simply a cut shape. However, it can be confirmed that the amount of electrodeposition by such electrolysis varies depending on the discharge rate and the potential difference of the battery, and the size of the spherical copper also varies. Accordingly, it can be confirmed that the size of the electrodeposited copper and the degree of contamination can be easily measured by controlling the discharge rate.

[0149]

[0150] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. As battery shreds including a positive electrode and a negative electrode, Contains copper, At least some of the copper is disposed on the surface of the cathode graphite, and The shape of the copper placed on the above cathode has a circular or elliptical shape, and Battery shredder in which the ratio of copper disposed on the above cathode is 4.3% or less based on 100% of the above cathode.

2. In Paragraph 1, The copper above is a battery fragment placed by leaching into the cathode.

3. In Paragraph 1, Battery fragmentation in which the ratio of copper disposed on the above cathode is 4.0% or less based on 100% of the above cathode.

4. In Paragraph 1, Battery crushed material having an average copper particle size (D50) of 1 to 7 μm.

5. A method for processing waste batteries to produce black mass by processing waste batteries that satisfy a first voltage, which is a cell unit voltage of a predetermined range. A first electric discharge step for electrically discharging the above waste battery; A second electric discharge step for electrically discharging the waste battery satisfying a second voltage lower than the first voltage; and A waste battery disposal method comprising the step of crushing the waste battery.

6. In Paragraph 5, A waste battery treatment method in which the first electric discharge step is performed in the range of 0.1 to 2.5 V / h.

7. In Paragraph 5, A method for processing a battery in which the second electric discharge step is a step of preventing voltage recovery of the waste battery that has undergone the first electric discharge step.

8. In Paragraph 5, A method for handling a battery in which the first voltage above is greater than 0.5 V.

9. In Paragraph 5, A method for processing a battery in which the second voltage is 0.5 V or less.

10. In Paragraph 5, The above second electric discharge step is a method for processing a battery using a resistive object having a resistance value higher than copper.

11. In Paragraph 10, A method for handling a battery having a resistance value of 1.68 * 10⁻⁸ ohm-m or greater.

12. In Paragraph 5, The above second electric discharge step is a method for processing a battery that performs a resistance discharge.

13. In Paragraph 5, The step of crushing the waste battery is a method for processing batteries in which the waste battery discharged to 1.0 V or less based on the cell is crushed.

14. In Paragraph 5, The waste battery that has undergone the second electric discharge step may include a step of atmospheric treatment, and The above-mentioned standby processing step is a method for processing a battery that is performed for more than 3 hours.

15. In Paragraph 1, A method for processing batteries comprising the step of classifying battery shreds generated from the step of shredding the waste batteries above.

16. In Paragraph 1, A method for processing a battery, comprising the step of drying the battery shreds generated from the step of shredding the waste battery at 150°C or lower.

17. In Paragraph 1, A method for processing batteries in which the proportion of copper in the battery shredder generated from the step of shredding the waste battery is 4.0% or less based on 100% of the negative electrode.

18. In Paragraph 17, The above copper is a method for processing a battery having a circular or elliptical shape.

19. A waste battery processing system for manufacturing black mass by processing waste batteries that satisfy a first voltage, which is a cell unit voltage of a predetermined range. A first discharge unit that electrically discharges a waste battery having a first voltage; A second discharge unit that electrically discharges the waste battery satisfying a second voltage lower than the first voltage; and A waste battery processing system including a waste battery crushing unit for crushing the above waste batteries.

20. In Paragraph 19, A waste battery processing system in which the first voltage above is greater than 0.5 V.

21. In Paragraph 19, The above-mentioned first discharge unit is a waste battery processing system that discharges the waste battery in the range of 0.1 to 2.5 V / h.

22. In Paragraph 19, A waste battery processing system in which the second voltage is 0.5 V or less.

23. In Paragraph 19, The above second discharge unit is a waste battery processing system that discharges the waste battery using a resistance object having a resistance value higher than copper.

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