Battery disposal method

Abstract

The present invention relates to a battery processing method, and the battery processing method of the present invention includes the steps of preparing a waste battery, measuring the average charge and discharge time of the waste battery, measuring the average charge and discharge time of a module-level waste battery from the waste battery and comparing it with the average charge and discharge time, and determining whether the module is normal based on whether the average charge and discharge time of a pack-level waste battery and the charge and discharge time of a module-level waste battery satisfy Formula 1 as specified herein.

Description

Technical Field

[0001] Relates to waste batteries, and more particularly to battery processing methods.

Background Art

[0002] For electric vehicles, where demand and supply are increasing rapidly due to environmental issues, battery technology is a core element. The waste batteries generated from the electric vehicles have become a social problem regarding the processing of the waste batteries. The problem of processing waste batteries generated from the electric vehicles has emerged as a social problem. The waste batteries use lithium-ion batteries and contain organic solvents, explosive substances, and heavy metal substances such as Ni, Co, Mn, Fe, and P, as well as carbon and other electrolyte substances. Among these, in the case of Ni, Co, Mn, Fe, P, and Li, the scarcity value as valuable metals is large, and the recovery and reuse processes after lithium secondary batteries are discarded have emerged as an important research field.

[0003] Specifically, a lithium secondary battery mainly consists of copper and aluminum used as current collectors, Li, Ni, Co, and Mn-containing oxides constituting the positive electrode, and graphite constituting the negative electrode, and includes a separator that separates the positive electrode and the negative electrode and an electrolyte injected into the separator. The electrolyte is composed of a solvent and a salt. The solvent mainly uses a mixture of carbonate organic substances such as ethylene carbonate and propylene carbonate, and as the salt, for example, LiPF6 is used.

[0004] The aforementioned lithium secondary batteries, including waste batteries, present technical challenges in safely dismantling them. These waste batteries may be discharged from process scrap generated during battery manufacturing, from overused electric vehicles, or from energy storage systems. These waste batteries exist in cell units, modules, or packs, and it is common practice to check the voltage at the pack or module level. In most cases, these waste batteries are generated when they reach the end of their lifespan, but in some cases, they may be generated when the electrodes short-circuit.

[0005] When the aforementioned waste battery is generated due to a short circuit in the electrodes, electrical discharge is impossible, making it important to distinguish between these. However, since a single battery pack has a structure in which over 100 cells are connected in series or parallel, it is not easy to find the cells that have short-circuited in the parallel structure, making electrical discharge difficult.

[0006] To solve these problems, a water discharge method is used in which waste batteries are separated into individual cells, their outer casings are cut open, and then they are immersed in water or saltwater to discharge them. However, this water discharge method can cause various problems in subsequent processes due to the sodium and chlorine in the wastewater or saltwater. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The technical problem that this invention aims to solve is to provide a battery processing method that safely discharges a battery even if it contains short-circuited cells, and reduces the risk of fire when the discharged battery is crushed. [Means for solving the problem]

[0008] A battery processing method according to one embodiment of the present invention may include the steps of: preparing a pack unit containing multiple modules or a waste battery having two or more modules; measuring the charge and discharge rate of the pack unit containing multiple modules or a waste battery having two or more modules to measure the average charge and discharge time; measuring the charge and discharge rate of the module unit of the waste battery to measure the average charge and discharge time of the module unit of the waste battery and comparing it with the average charge and discharge time; and determining whether a module is normal or defective based on whether the average charge and discharge time of the pack unit of the waste battery and the charge and discharge time of the module unit of the waste battery satisfy the following formula 1.

[0009] <Expression 1>

number

[0010] (In the above equation 1, t aver This refers to the average charge and discharge average time per module for waste batteries in packs containing multiple modules or for waste batteries with two or more modules, and t module (This refers to the charge and discharge time / number of cells for a waste battery module.)

[0011] In one embodiment, the process may include a step of electrically discharging a normal module satisfying the above formula 1 to 0.1V or less. In one embodiment, the process may include a step of grounding the normal module after the step of electrically discharging it.

[0012] In one embodiment, the process may include a step of crushing the normal module that has undergone the electrical discharge. In one embodiment, the step of crushing the normal module may be performed with an inert gas.

[0013] In one embodiment, the step of crushing the normal module may be performed in an atmosphere with an oxygen concentration of 3% or less. In one embodiment, the step after crushing the normal module may include a step of drying the crushed material at a temperature of 200°C or less. In one embodiment, the step of measuring the charge and discharge rates of the waste battery and determining the average charge and discharge rate may be performed by charging and discharging the waste battery at a constant voltage or constant current.

[0014] A battery processing method according to another embodiment of the present invention may include the steps of: preparing a waste battery in module units containing a plurality of cells; measuring the charge and discharge rates of the waste battery; evaluating the temperature of each cell within the module; and determining whether the module is normal or defective based on whether the temperature deviation of each cell satisfies 3°C or less.

[0015] In one embodiment, the process may include a step of electrically discharging the normal module at 0.1V or less. In one embodiment, the process may include a step of crushing the electrically discharged normal module in an atmosphere with an oxygen concentration of 0.5% or less. In one embodiment, the process may include a step of drying the crushed material at a temperature of 200°C or less after the step of crushing the normal module. In one embodiment, the process may include a step of cryopreserving and crushing the defective module.

[0016] The battery processing method according to another embodiment of the present invention includes the steps of preparing a pack unit including a plurality of modules or a waste battery having two or more modules, measuring the charging and discharging speeds of the pack unit including the plurality of modules or the waste battery having two or more modules to measure the average charging and discharging times, measuring the charging and discharging speeds of the waste battery in module units to measure the charging and discharging times of the waste battery in module units, and comparing them with the average charging and discharging times, determining normal modules or defective modules of the waste battery in module units, crushing the normal modules or defective modules, and drying the crushed product at a temperature of 200 °C or lower, and the dried product can satisfy the following formula 2.

[0017] <Formula 2>

Number

[0018] (In the above formula 2, w1 and w2 respectively mean the initial weight (Kg) of the crushed product and the weight (Kg) of the dried product)

[0019] In one embodiment, the step of measuring the charging and discharging speeds in module units, comparing them with the average charging and discharging speeds, and determining normal modules or defective modules may include the step of determining whether the following formula 1 is satisfied.

[0020] <Formula 1>

Number

[0021] In one embodiment, after measuring the charging and discharging speeds in module units and comparing them with the average charging and discharging speeds, the step of electrically discharging normal modules that satisfy Equation 1 above may be included at 0.1 V or less. In one embodiment, after measuring the charging and discharging speeds in module units and comparing them with the average charging and discharging speeds, the step of freezing defective modules that do not satisfy Equation 1 above may be performed within a temperature range of -20°C or lower.

Effects of the Invention

[0022] A battery processing method according to one embodiment provides a battery processing method that discharges a battery safely even when including a short-circuited cell by checking the presence or absence of a short circuit in cell units through electrical discharge and performing a crushing process safely, reducing the risk of fire during crushing of the discharged battery.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a diagram in which the temperature is measured with a thermal imaging camera for the battery module itself of the present invention. [Figure 2a] FIG. 2a is a graph regarding the temperature rise before and during battery crushing. [Figure 2b] FIG. 2b is a graph regarding the temperature rise before and during battery crushing.

Modes for Carrying Out the Invention

[0024] 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 only used to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Therefore, the first part, component, region, layer, or section described below can be referred to as the second part, component, region, layer, or section within a scope that does not deviate from the scope of the present invention.

[0025] The technical terms used herein are for the sole purpose of referring to specific embodiments and are not intended to limit the invention. The singular forms used herein also include plural forms unless the text explicitly indicates otherwise. The meaning of “including” as used in this specification is to embody specific characteristics, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0026] When one part is described as being "on top of" another part, it means that it is either directly on top of the other part or that the other part is in between. In contrast, when one part is described as being "directly on top of" another part, there is no other part in between.

[0027] Although not defined differently, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by a person of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries are additionally interpreted as having the meaning consistent with the relevant technical literature and the present disclosure, and are not interpreted in their ideal or highly formal sense unless otherwise defined.

[0028] Embodiments of the present invention will be described in detail below. However, these are presented as examples only and do not limit the present invention, which is defined only by the scope of the claims described later.

[0029] A battery processing method according to one embodiment of the present invention may include the steps of preparing a waste battery in the form of a module containing multiple cells or a pack containing multiple modules, and determining whether a module is normal or defective. Specifically, the battery processing method of the present invention may be a battery processing method that determines whether a module is normal or defective by measuring the charge and discharge rate of a battery in the form of a module or pack, safely discharges the battery, and reduces the risk of fire when the battery is crushed.

[0030] The step of preparing a waste battery having a module containing multiple cells, a pack containing multiple modules, or two or more modules may be a lithium secondary battery separated from an automobile, a secondary battery separated from an electronic device such as a mobile phone, camera, or laptop computer, specifically a lithium secondary battery. The lithium secondary battery may be a battery in the form of a module containing multiple cells, or a waste battery in the form of a pack containing multiple modules. The waste battery may include normal modules having a voltage of approximately 2.0 to 4.5V relative to the cells, and defective modules that are short-circuited and whose voltage measurement is not easy.

[0031] In the step of preparing the waste battery, if the waste battery is a pack containing multiple modules or has two or more modules, the step of measuring the charge and discharge rate of the waste battery to determine the average charge and discharge rate may be included. Specifically, the step of measuring the charge and discharge rate of the waste battery to determine the average charge and discharge rate can be performed using constant-voltage discharge / recharge or constant-current discharge / recharge to ensure uniform charging and discharging. This allows for calculating the average charge and discharge time of a module by dividing the time taken to charge and discharge the entire pack by the number of modules.

[0032] After the step of measuring the charge and discharge rates of a waste battery in a pack containing multiple modules or a waste battery having two or more modules, and determining the average charge and discharge rate, the waste battery in the pack can be disassembled into module units. Specifically, this may be a pre-processing step to disassemble the waste battery in the pack, which is arranged in multiple module units, and calculate the charge and discharge rate of each module.

[0033] The process includes disassembling the waste battery pack into module units, measuring the charge and discharge rates of each module to determine the charge and discharge time of the waste battery module, and comparing it to the average charge and discharge time. Specifically, this may involve comparing the charge and discharge times of multiple waste battery modules with the average charge and discharge time of the waste battery pack.

[0034] The average charge and discharge time of a waste battery in a pack containing multiple modules or a waste battery with two or more modules, and the charge and discharge time of a waste battery in a module unit, can be used to determine whether or not the following formula 1 is satisfied. Specifically, if the average charge and discharge time of a waste battery in a pack containing multiple modules or a waste battery with two or more modules, and the charge and discharge time of a waste battery in a module unit, satisfy the following formula 1, it can be determined that it is a normal module; if it does not satisfy the above formula 1, it can be determined that it is a short-circuited module where a short circuit has occurred and charging and discharging does not proceed smoothly.

[0035] <Expression 1>

number

[0036] (In the above equation 1, t aver This refers to the average charge and discharge time of a waste battery in a pack containing multiple modules or a waste battery with two or more modules / the number of waste batteries per module. module (This refers to the charge and discharge time / number of cells for a waste battery module.)

[0037] Satisfying Equation 1 above means that the difference between the average charge and discharge time of a pack of used batteries and the charge and discharge time of a module of used batteries, divided by the average charge and discharge time of the pack of used batteries, is smaller than the fraction of cells in the module of used batteries. This can be an indicator of whether the module is functioning correctly. Conversely, not satisfying Equation 1 above means that the difference between the average charge and discharge time of a pack of used batteries and the charge and discharge time of a module of used batteries, divided by the average charge and discharge time of the pack of used batteries, is larger than the fraction of cells in the module of used batteries. This implies that at least one cell in the module is defective due to a short circuit or other reason.

[0038] Thus, the present invention allows for easy determination of whether the modules within a used battery are functioning normally or defective by measuring the charging and discharging speed of the used battery, calculating the charging and discharging time, and based on this, determining whether the modules within the used battery are functioning normally or defective.

[0039] In one embodiment, the process may include a step of electrically discharging a normal module satisfying Equation 1 to 0.1V or less. Specifically, a normal module satisfying Equation 1 is a module whose voltage can be reduced by electrical discharge, and by performing electrical discharge, the voltage of the module can be reduced to 0.1V or less relative to the cell, specifically to 0.8V or less, and more specifically to 0.5V or less. When the normal module is electrically discharged within the aforementioned range, no sparks are generated in the subsequent step of crushing the cell, and no smoke or fire is generated, so the process can be carried out safely. In contrast, if the voltage is outside the aforementioned range, safety problems may arise during the execution of the process.

[0040] In one embodiment, a faulty module that does not satisfy Equation 1 above may include a step of freezing it. The faulty module is a module that has a problem such as a short circuit and is unable to lower the cell reference voltage within the module through electrical discharge. By freezing the faulty module, the module can be easily discharged without generating wastewater, as in saltwater discharge.

[0041] In one embodiment, the step of freezing the defective module may be performed in a temperature range of -20°C or lower. In one embodiment, the step of freezing the defective module is performed at a temperature sufficient to freeze the electrolyte contained in the battery. Specifically, the step of freezing the defective module may be performed in a temperature range of, for example, -150 to -20°C. More specifically, the temperature range may be -150 to -50°C, and even more specifically, -80 to -60°C.

[0042] When the defective module is frozen within the temperature range, the voltage remaining inside the battery, for example, a voltage of about 2V to 3V, drops to near 0V. Therefore, even if a short circuit occurs where the positive and negative electrodes are in direct contact, no battery reaction occurs, the battery temperature does not increase, and gas generation and combustion of the electrolyte do not occur. Furthermore, since the electrolyte is in a frozen state or in a state where vaporization is suppressed, the mobility of lithium ions is very low, which can significantly reduce the current-carrying characteristics due to lithium ion movement. As a result, since the electrolyte does not vaporize, flammable gases such as ethylene, propylene, and hydrogen may not be generated.

[0043] If the freezing process falls outside the temperature range, the voltage remaining inside the battery will not drop to 0V, which may cause a battery reaction due to a short circuit, and the electrolyte will not be completely frozen, making it unsuitable. Thus, the battery processing method, by including a step of freezing defective modules before crushing batteries such as lithium secondary batteries, has the advantage of easily discharging defective modules that are difficult to discharge electrically and preventing the risk of fire that may occur in the battery crushing process.

[0044] In one embodiment, the step of freezing the defective module may be performed for 15 to 36 hours. Alternatively, the step of freezing the defective module may be performed for 20 to 30 hours, specifically 22 to 27 hours. By performing the step of freezing the defective module within the aforementioned time range, battery stabilization can be easily carried out, and if the battery is to be crushed, a fire from the battery can be prevented.

[0045] If the step of freezing the defective module takes significantly longer than the specified time, it becomes economically unfeasible. If the step of freezing the defective module is performed for significantly less time than the specified time, battery stabilization does not occur easily.

[0046] In one embodiment, the battery processing method may include a step of grounding the normal module after the step of electrical discharge. Specifically, the discharged battery, for example, the (+) and (-) terminals of the module, can be grounded to maintain a continuously discharged state. Including the grounding step prevents the voltage of the waste battery from recovering due to the standard reduction potential difference. In one embodiment, the step of grounding the normal module may be performed for 6 hours or more. Specifically, the step of grounding the module may be performed for 8 hours or more.

[0047] In one embodiment, the battery processing method may include a step of crushing the normal module that has undergone the electrical discharge step or the defective module that has undergone the freezing step. Specifically, this may mean a step of applying impact or pressure to the battery so that a part of the battery falls off from the battery, whether it is a normal module that has undergone the electrical discharge step or a defective module that has undergone the freezing step. The step of crushing the normal or defective module may mean a step of pulverizing the battery, a step of cutting the battery, a step of compressing the battery, and all combinations thereof. Specifically, the crushing step may include all steps of destroying the battery, whether it is a normal or defective module, to obtain small pieces of crushed material.

[0048] In one embodiment, the step of crushing the normal or defective module may include all steps of compressing the battery, which is the normal or defective module, or destroying the battery by applying an external force such as a shear force or a tensile force. The step of crushing the normal or defective module may be carried out, for example, using a crusher.

[0049] In one embodiment, the step of crushing the normal or defective module can be performed at least once. Specifically, the crushing step can be performed at least once, either continuously or discontinuously.

[0050] In one embodiment, the step of crushing normal or defective modules can be carried out under conditions of supplying an inert gas, carbon dioxide, nitrogen, water, or a combination thereof, or under a vacuum atmosphere of 100 torr or less. Performing the step of crushing normal or defective modules under the aforementioned gas atmosphere allows the process to be carried out more safely than when it is carried out in the atmosphere.

[0051] In one embodiment, the step of crushing normal or defective modules may be carried out in an atmosphere with an oxygen concentration of 3% or less. Specifically, the step of crushing normal or defective modules may be carried out with an oxygen concentration of 3% or less by volume, and more specifically, 0.1% or less. In one embodiment, the step of crushing normal or defective modules may be carried out within 6 hours.

[0052] In the crushing step, if the oxygen concentration satisfies the aforementioned range, the safety issues in the process can be resolved. However, if the oxygen concentration is excessively high, exceeding 6%, there is a problem of fire occurring when sparks are generated in the waste battery, due to a reaction with the electrolyte.

[0053] In one embodiment, the process may include a step of drying the crushed material at a temperature of 200°C or less, following the step of crushing the normal or defective module. The drying step may also be a step of removing the electrolyte from the crushed material.

[0054] In one embodiment, the drying step can be performed using hot air. Specifically, hot air using gas can be applied to the crushed result to remove the electrolyte from the crushed result.

[0055] In one embodiment, the gas for the hot air may be an inert gas. For example, the inert gas may be carbon dioxide, nitrogen, argon, helium, or a combination thereof. Using an inert gas as the gas for the hot air has advantages from the standpoint of fire prevention.

[0056] In one embodiment, the drying step may be carried out in an atmosphere with an oxygen concentration of 5% or less. By ensuring that the oxygen concentration in the drying step satisfies the aforementioned range, the possibility of smoke or fire generation can be reduced. Specifically, some of the shredded battery material may regain voltage over time, and at this time, smoke may be generated by a reaction with the volatile electrolyte. By drying within the aforementioned oxygen concentration range, the possibility of smoke generation from the battery material can be significantly reduced.

[0057] In one embodiment, the drying step may be carried out within 6 hours, specifically within 4 hours. When the inert gas is used in the drying step, if the oxygen concentration falls outside the range described above, it may lead to safety issues during the execution of the process.

[0058] In one embodiment, the dried product obtained through the drying step can satisfy the following formula 2.

[0059] <Expression 2>

number

[0060] (In Equation 2 above, w1 and w2 represent the initial weight (kg) of the crushed product and the weight (kg) of the dried product, respectively.)

[0061] Equation 2, mentioned above, represents the weight change when the crushed product is dried, and can serve as an indicator of electrolyte volatilization. Equation 2 can satisfy a range of 10% or less, specifically 2.0 to 8.0%, and more specifically, 3.8 to 7.8%. When Equation 2 satisfies the aforementioned range, more than 40% of the electrolyte in the crushed product volatilizes, and a stabilized crushed product can be obtained. If Equation 2 falls outside the aforementioned range, the electrolyte cannot be easily removed, which raises safety concerns or reduces process efficiency.

[0062] Another embodiment of the present invention provides a method for processing batteries in module units, each containing multiple cells. The battery processing method may include the steps of: preparing a waste battery in module units containing multiple cells; measuring the charge and discharge rates of the waste battery; evaluating the temperature of each cell within the module; and determining whether the module is normal or defective based on whether the temperature deviation of each cell satisfies 3°C or less.

[0063] The step of measuring the charge and discharge rates of the waste battery in module units, which include the plurality of cells, may be performed in the same manner as the method for measuring the charge and discharge rates of the waste battery in module units, as described above in the battery processing method for waste batteries in pack units, which include the plurality of modules.

[0064] A normal module satisfying Equation 3 above may include steps of electrical discharge, crushing, and drying, similar to the method of processing batteries from the pack-unit waste batteries described above. A defective module not satisfying Equation 3 above may include steps of freezing, crushing, and drying, similar to the method of processing batteries from the pack-unit waste batteries described above, and a detailed explanation thereof can be found in the above description to the extent that it does not contradict the above. [Examples]

[0065] The present invention is described in detail. However, the following examples are merely preferred embodiments of the present invention, and the present invention is not limited to these examples.

[0066] <Experimental Example 1>: Method for determining and processing normal modules in a battery pack Battery preparation steps In this invention, the battery is prepared as a module containing multiple cells, and as a battery pack containing multiple such modules.

[0067] Determining whether there is a short circuit in the battery The battery pack was charged and discharged. During this process, constant-voltage discharge / recharge or constant-current discharge / recharge was used to ensure uniform charging and discharging. This was done because multiple modules were arranged within the pack, and the average charge / discharge time for each module was calculated by dividing the total charge / discharge time for the entire pack by the number of modules. Subsequently, the modules were disassembled individually. After disassembly, each module was charged and discharged, using the same constant-voltage or constant-current discharge values ​​as used for the pack.

[0068] At this time, if you divide the average charge / discharge time of the pack by the number of modules, you get the average charge / discharge time of the modules (t aver The following is calculated: By comparing the charge and discharge rates of the separated modules, if a difference in charge and discharge rates of the separated modules exceeds a certain time, it can be determined that the module in question is the one that experienced a short circuit.

[0069] Average charge / discharge time (t aver The specified time was calculated using the following relational formula.

[0070] <Average charge / discharge time (t aver )> t aver = Average charge / discharge time per pack / Number of modules

[0071] <Specific time>

number

[0072] Through the above formula, if the difference between the average charge / discharge time of the pack and the average discharge time of the module is smaller than the fraction of the number of cells in the module, it is determined to be a normal module. If, through the above formula, the difference between the average charge / discharge time of the pack and the average discharge time of the module is larger than the fraction of the number of cells in the module, there is a high probability that at least one cell is defective due to a short circuit or the like, and it is determined to be a defective module.

[0073] Performing an electrical discharge on a normal module The above-mentioned average charge / discharge ratio and the specified time satisfy the aforementioned relationship, and an electrical discharge was performed on a normal module. During the electrical discharge, the presence or absence of sparks, smoke, and fire was measured while the cells were crushed by the voltage multiple times.

[0074] After discharge, the positive and negative terminals of the module were grounded to maintain continuous discharge and prevent voltage recovery due to the standard reduction potential difference. The grounding was maintained for at least 6 hours.

[0075] Table 1 below shows the results of measurements taken during the execution of an electrical discharge, specifically regarding the presence or absence of sparks due to voltage, as well as the presence or absence of smoke and fire.

[0076] The presence or absence of sparks, smoke, and fire was measured using the following method.

[0077] Spark generation: When measuring temperature using a thermal imaging camera, we checked whether the temperature rose by 20 degrees or more. If it was 20 degrees or more, we determined that a spark had occurred and indicated it as ○. If it was between 10 and 20 degrees, we indicated it as △. If the temperature did not rise and was below 10 degrees, we determined that no spark had occurred and indicated it as ×.

[0078] Presence or absence of smoke and fire: The presence or absence of smoke and fire was determined by visually observing for smoke or fire during the electrical discharge. ○ was used to indicate the presence of smoke or fire, and × was used to indicate the absence of smoke or fire.

[0079] [Table 1]

[0080] As shown in Table 1 above, it was confirmed that when electrical discharge was performed at a voltage lower than 1.0V relative to the cells in a module consisting of a series-parallel structure, no sparks were generated, and when electrical discharge was performed at a voltage lower than 2.0V, no smoke was generated. Figures 2a and 2b are graphs showing the temperature rise before and during battery crushing.

[0081] Figure 2a is a graph showing the temperature rise before crushing, and Figure 2b is a graph showing the temperature rise during battery crushing. It was confirmed that no temperature rise occurred before battery crushing, and that a temperature rise peak occurred when sparks were generated during battery crushing.

[0082] Battery destruction The aforementioned battery was crushed using a crusher. At this time, there was a possibility of additional fire occurring inside the crusher, so an inert gas such as nitrogen, argon, or carbon dioxide was introduced to maintain the oxygen level at 1 wt% or less. Furthermore, since the crushed material retains the structure of the battery even after being crushed, the size of the crushed material was adjusted so that it was within 100 mm relative to the long axis of the crushed material.

[0083] Removal of electrolyte from crushed material The electrolyte within the crushed material was removed by supplying hot air. Either air or nitrogen (N2) gas, an inert gas, was used as the hot air source. When air was used, the oxygen concentration was maintained at approximately 21%, and when an inert gas was used, the oxygen concentration was maintained at 5% or less. The presence or absence of smoke generation was then determined based on time. The hot air temperature was set to 120°C, and drying was carried out for 12 hours.

[0084] Table 2 below shows whether or not smoke is generated when hot air is supplied to the crushed material, depending on the conditions of the atmosphere and inert gas.

[0085] Smoke generation: To determine whether smoke was generated from the crushed material, the material was placed on a rotatable table and rotated slowly at 10 rpm for 4 hours. Smoke generation was indicated by ○, no smoke was generated but there was a burning smell or heat haze was indicated by △, and no smell or heat haze was generated at all, i.e., no smoke was generated, was indicated by ×.

[0086] [Table 2]

[0087] As shown in Table 2 above, when hot air is applied to the crushed material, no smoke is generated when the treatment time is within 2 hours under atmospheric conditions, and no smoke is generated when the treatment time is within 6 hours under inert gas conditions, thus confirming that there is no risk of fire.

[0088] Weight measurement test of crushed material Table 3 below shows the change in the weight of the crushed material over time when nitrogen gas is used as hot air and the temperature of the hot air is set to 120°C during the electrolyte drying step. The weight of the crushed material was measured by the following method.

[0089] Weight of crushed material: The weight of the crushed material was measured using a scale. The initial weight was the weight of the crushed material measured within one minute after crushing in the pre-drying step, the weight after drying was the weight of the crushed material after the step of drying with hot air, and the weight change rate was calculated by converting the change in weight after drying based on the initial weight of the crushed material.

[0090] [Table 3]

[0091] As seen in Table 2 above, it was confirmed that smoke was generated from the crushed material when the weight change rate was 2% or less. However, it was confirmed that no smoke was generated when the weight change rate of the crushed material was 3% or more. A change of approximately 6% in the weight specific gravity of the crushed material theoretically means that the electrolyte content decreased by 40% or more, since the total electrolyte content is approximately 12 to 13%.

[0092] <Experimental Example 2>: Method for identifying and handling defective modules in a battery pack In Experimental Example 1, defective modules were identified based on the presence or absence of a short circuit within the battery, and these defective modules were frozen without further electrical discharge. In the case of an internal short circuit, electrical discharge would not occur, so the modules were rendered harmless by freezing. Specifically, the defective modules were subjected to cryogenic treatment at -60°C for 24 hours.

[0093] Subsequently, the cryogenically treated batteries were crushed using a general crushing device, and the battery crushing step and subsequent drying steps were carried out in the same manner as in Experimental Example 1. The freezing temperature during cryopreservation may vary depending on the charge level of the waste battery. When the charge level is 3V or less relative to the cell, the freezing temperature is -50°C or lower, and when it is 3.5V or less, it is -70°C or lower. When it is 3.5V or higher, it is carried out at -90°C.

[0094] After crushing, it is necessary to store the material in a stabilization system without rotation, during which time the temperature rises due to self-heating. The crushing conditions for the material are most preferably within 10-50 mm, and the average size of the crushed material is most preferably 10-30 mm. If the size is larger than this, the risk of fire increases, and if it is smaller than 10 mm, difficulties occur where the material gets stuck between the crushing blades during crushing.

[0095] <Experimental Example 3>: Judgment and processing method for the battery module itself In the battery preparation step of Experimental Example 1, a battery module containing multiple cells, rather than a battery pack, was prepared. The battery module may have a parallel structure using two cells, or it may have a parallel structure with up to three or four cells. This varies depending on the battery module design. When charging and discharging a battery, heat is generated due to the movement of electric charge, but in cases where the battery is visible from the outside, a thermal imaging camera can detect short-circuited cells based on temperature deviations alone. During charging and discharging, the amount of heat generated increases as the standard potential of a ternary battery rises above 2.5V. Below 2.5V, the internal structure deforms, and the amount of heat generated increases.

[0096] Figure 1 shows the temperature of the battery module of the present invention measured using a thermal imaging camera.

[0097] Referring to Figure 1, in this invention, charging and discharging are distinguished separately. During discharging, the external case is removed, and temperature deviations between individual modules are measured via a thermal imaging camera. The figure below shows the temperature deviation in the module; if a short circuit occurs in the center, a gradual temperature rise will appear. An internal short circuit was confirmed when the temperature deviation differed by approximately 3°C or more compared to the surrounding area. In most normal cells, it was confirmed that temperature deviations occurred at 3°C ​​or less.

[0098] Although preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

Claims

1. Steps include preparing a waste battery in the form of a pack containing multiple modules or having two or more modules; A step of measuring the charging and discharging speed of the waste battery and determining the average charging and discharging time; A step of measuring the charge and discharge rates of module-level waste batteries within the waste battery, measuring the average charge and discharge time of module-level waste batteries, and comparing it with the average charge and discharge time; and A battery processing method comprising the step of determining whether a module is normal or defective based on whether the average charge and discharge time of a waste battery in a pack unit containing multiple modules or having two or more modules, and the charge and discharge time of a waste battery in a module unit, satisfy the following formula 1. <Formula 1> [Math 1] (In the above equation 1, t ａｖｅｒ This refers to the average charge and discharge average time of a waste battery in a pack containing multiple modules or a waste battery having two or more modules / the number of waste batteries per module, t ｍｏｄｕｌｅ This refers to the charge and discharge time / number of cells for a waste battery module.

2. The battery processing method according to claim 1, comprising the step of electrically discharging a normal module that satisfies the above formula 1 to 0.1V or less.

3. The battery processing method according to claim 2, further comprising the step of grounding the normal module after the step of discharging electricity.

4. The battery processing method according to claim 2, further comprising the step of crushing the normal module that has undergone the aforementioned electrical discharge.

5. The battery processing method according to claim 4, wherein the step of crushing the normal module is performed with an inert gas.

6. The battery processing method according to claim 4, wherein the step of crushing the normal module is carried out in an atmosphere with an oxygen concentration of 3% or less.

7. After the step of crushing the normal module, The battery processing method according to claim 3, further comprising the step of drying the crushed result at a temperature of 200°C or less.

8. The drying step is carried out in an atmosphere with an oxygen concentration of 5% or less. The battery processing method according to claim 7.

9. The battery processing method according to claim 1, further comprising the step of freezing the defective module.

10. The battery processing method according to claim 9, wherein the step of freezing the defective module is performed in a temperature range of -20°C or lower.

11. The battery processing method according to claim 1, wherein the step of measuring the charge and discharge rate of the waste battery and determining the average charge and discharge rate is performed by charging and discharging the waste battery with a constant voltage or constant current.

12. Steps to prepare waste batteries in module units containing multiple cells; A step of measuring the charging and discharging speed of the aforementioned waste battery; A step of evaluating the cell-level temperature within the module; and A battery processing method comprising the step of determining whether a module is normal or defective based on whether the temperature deviation of the cell unit is 3°C or less.

13. The battery processing method according to claim 12, further comprising the step of electrically discharging the normal module to 0.1V or less.

14. The battery processing method according to claim 13, further comprising the step of crushing the normal module that has undergone the electrical discharge in an atmosphere with an oxygen concentration of 0.5% or less.

15. After the step of crushing the normal module, The battery processing method according to claim 14, further comprising the step of drying the crushed result at a temperature of 200°C or less.

16. The battery processing method according to claim 12, further comprising the step of freezing and crushing the defective module.

17. Steps include preparing a waste battery in the form of a pack containing multiple modules or having two or more modules; A step of measuring the charging and discharging speed of the waste battery and determining the average charging and discharging time; A step of measuring the charge and discharge rates of a waste battery in a pack unit containing multiple modules or in a module unit within a waste battery having two or more modules, measuring the charge and discharge time of the waste battery in the module unit, and comparing it with the average charge and discharge time; A step of determining whether the waste battery module is a normal module or a defective module; Steps of crushing the normal module or the defective module; and The step includes drying the crushed result at a temperature of 200°C or lower. The aforementioned dried result satisfies the following equation 2, a battery processing method. <Formula 2> [Math 2] (In the above equation 2, w １ and w ２ (These represent the initial weight (kg) of the crushed product and the weight (kg) of the dried product, respectively.)

18. The battery processing method according to claim 17, wherein the step of measuring the charge and discharge rate for each module and determining whether a module is normal or defective by comparing it with the average charge and discharge rate includes the step of determining whether the following formula 1 is satisfied. <Formula 1> [Math 3]

19. The following steps are taken: measuring the charge and discharge rates for each module and comparing them with the average charge and discharge rates; The battery processing method according to claim 18, comprising the step of electrically discharging a normal module that satisfies the above formula 1 to 0.1V or less.

20. The following steps are taken: measuring the charge and discharge rates for each module and comparing them with the average charge and discharge rates; The battery processing method according to claim 17, wherein the step of freezing defective modules that do not satisfy the above formula 1 is performed in a temperature range of -20°C or lower.

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