WO2025135674A1 - Battery processing method - Google Patents

Abstract

The present invention relates to a battery processing method, and the method comprises the steps of: preparing waste batteries; measuring an average charging and discharging time of the waste batteries; measuring an average charging and discharging time of module-unit waste batteries among the waste batteries, and comparing the measured value with the average charging and discharging time of the waste batteries; and depending on whether an average charging and discharging time of pack-unit waste batteries and a charging and discharging time of a module-unit waste battery satisfy equation 1 according to the present specification, determining whether a corresponding module is normal.

Description

How to dispose of batteries

It relates to waste batteries, and more specifically, to methods of disposing of batteries.

Electric vehicles, the supply and demand of which are rapidly increasing due to environmental issues, require battery technology as a key element. The disposal of waste batteries generated from said electric vehicles has become a social problem. The disposal of waste batteries generated from said electric vehicles has become a social problem. The waste batteries use lithium ion batteries and contain organic solvents, explosive materials, and heavy metals such as Ni, Co, Mn, Fe, and P, as well as carbon and other electrolyte materials. Among these, Ni, Co, Mn, Fe, P, and Li have high scarcity value as valuable metals, and the recovery and recycling process after the lithium secondary battery is disposed of is emerging as an important research field.

Specifically, a lithium secondary battery mainly consists of copper and aluminum used as a current collector, Li, Ni, Co, and Mn-containing oxides forming a cathode, and graphite forming a cathode, a separator separating the cathode and the anode, and an electrolyte injected into the separator. The solvent used as the solvent and salt forming the electrolyte is mainly a mixture of carbonate organic substances such as ethylene carbonate and propylene carbonate, and for example, LiPF ₆ is used.

The waste batteries including the above lithium secondary batteries have technical issues that require safe dismantling. The waste batteries may be produced as process scraps during battery manufacturing, or may be discharged from electric vehicles or energy storage devices after use. The waste batteries exist in units of cells, modules, or packs, and it is common to check the voltage by unit of pack or module. In the case of the above waste batteries, there are many cases where they are produced as waste batteries due to the end of their lifespan, but in some cases, they are produced due to short-circuiting of electrodes.

In the case where the above-mentioned waste battery is caused by a short circuit in the electrodes, it is important to distinguish it because electrical discharge is impossible. However, since one pack is structured with hundreds of cells connected in series or parallel, it is difficult to find a short-circuited cell in the parallel structure, making it difficult to perform electrical discharge.

To solve these problems, a water discharge method is being utilized in which waste batteries are separated into cell units, the outer shell is cut open, and the batteries are immersed in water or salt water to discharge them. However, the sodium and chlorine in the waste water or salt water can cause various problems in the subsequent process.

The technical problem to be solved by the present invention 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 crushing the discharged battery.

According to one embodiment of the present invention, a battery processing method may include a step of preparing a waste battery having a pack unit including a plurality of modules or two or more modules, a step of measuring a charge and discharge rate of the waste battery having the pack unit including the plurality of modules or two or more modules to measure an average charge and discharge time, a step of measuring the charge and discharge rate of the waste battery having the module unit to measure an average charge and discharge time of the waste battery having the module unit and comparing the measured charge and discharge time with the average charge and discharge time, and a step of determining a normal module or a defective module based on whether the average charge and discharge time of the waste battery having the pack unit and the charge and discharge time of the waste battery having the module unit satisfy the following Equation 1.

<Formula 1>

(In the above equation 1, t _aver means the average charge and discharge time of a pack unit including multiple modules or the number of waste batteries per module unit having two or more modules, and t _module means the charge and discharge time of a waste battery per module unit/the number of cells.)

In one embodiment, the step of electrically discharging a normal module satisfying the above formula 1 to 0.1 V or less may be included. In one embodiment, after the electrically discharging step, the step of grounding the normal module may be included.

In one embodiment, the step of crushing the normal module that has performed the electric discharge may be included. In one embodiment, the step of crushing the normal module may be performed in an inert gas.

In one embodiment, the step of crushing the normal module may be performed in an atmosphere having an oxygen concentration of 3% or less. In one embodiment, after the step of crushing the normal module, the step of drying the crushed result at a temperature of 200° C. or less may be included. In one embodiment, the step of measuring the charge and discharge rates of the waste battery to determine an average charge and discharge rate may be performed by charging and discharging the waste battery at a constant voltage or constant current.

According to another embodiment of the present invention, a battery processing method may include a step of preparing a waste battery in a module unit including a plurality of cells, a step of measuring a charge and discharge rate of the waste battery, a step of evaluating a temperature of a cell unit within the module, and a step of determining a normal module or a defective module based on whether a temperature deviation of the cell unit satisfies 3° C. or less.

In one embodiment, the method may include a step of electrically discharging the normal module to 0.1 V or less. In one embodiment, the method may include a step of crushing the normal module, which has undergone the electrical discharge, in an atmosphere having an oxygen concentration of 0.5% or less. In one embodiment, the method may include a step of drying the crushed result at a temperature of 200° C. or less after the step of crushing the normal module. In one embodiment, the method may include a step of freeze-crushing the defective module.

According to another embodiment of the present invention, a battery processing method includes the steps of preparing a waste battery having a pack unit including a plurality of modules or two or more modules, measuring a charge and discharge rate of the waste battery having the pack unit including the plurality of modules or two or more modules to measure an average charge and discharge time, measuring the charge and discharge rate of the module-unit waste battery to measure the charge and discharge time of the module-unit waste battery and comparing the measured charge and discharge time with the average charge and discharge time, determining a normal module or a defective module of the module-unit waste battery, crushing the normal module or the defective module, and drying the crushed resultant at a temperature of 200°C or less, wherein the dried resultant can satisfy the following Equation 2.

<Formula 2>

(In the above formula 2, w ₁ and w ₂ represent the initial weight (Kg) of the crushed result and the weight (Kg) of the dried result, respectively)

In one embodiment, the step of measuring the charge and discharge rates of each module and comparing them with the average charge and discharge rates to determine whether the module is normal or defective may include a step of determining whether the following Equation 1 is satisfied.

<Formula 1>

In one embodiment, after the step of measuring the charge and discharge rates for each module and comparing them with the average charge and discharge rates, the step of electrically discharging a normal module satisfying Equation 1 to 0.1 V or less may be included. In one embodiment, after the step of measuring the charge and discharge rates for each module and comparing them with the average charge and discharge rates, the step of freezing a defective module not satisfying Equation 1 may be performed in a temperature range of -20° C. or less.

According to one embodiment of the present invention, a battery processing method is provided, which safely discharges a battery even if it includes a short-circuited cell by checking whether a cell is short-circuited through electrical discharge and safely performing a shredding process, and reduces the risk of fire when shredding the discharged battery.

Figure 1 is a drawing showing the temperature of the battery module itself of the present invention measured using a thermal imaging camera.

Figures 2a and 2b are graphs of temperature rise before and during battery crushing.

The terms first, second, and third, etc. are used to describe, but are not limited to, various parts, components, regions, layers, and/or sections. These terms are only used to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Thus, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms include the plural forms as well, unless the context clearly dictates otherwise. The word "comprising," as used herein, specifies particular features, regions, integers, steps, operations, elements, and/or components, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and/or components.

When a part is referred to as being "on" or "on" another part, it may be directly on or above the other part, or there may be other parts intervening. In contrast, when a part is referred to as being "directly on" another part, there are no other parts intervening.

Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted in an ideal or very formal sense unless defined.

Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples, and the present invention is not limited thereby, and the present invention is defined only by the scope of the claims described below.

According to one embodiment of the present invention, a battery processing method may include a step of preparing a waste battery in the form of a module including a plurality of cells or a pack including a plurality of modules, and a step of determining a normal module or a defective module. Specifically, the battery processing method of the present invention may be a battery processing method that safely discharges a battery and reduces the risk of fire when the battery is crushed by determining a normal module or a defective module by measuring a charge/discharge rate of a battery in the form of a module or a pack.

The step of preparing a module including a plurality of cells, a pack including a plurality of modules including a plurality of modules, or a spent battery having 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, a camera, or a laptop, specifically a lithium secondary battery. The lithium secondary battery may be a battery in a module unit including a plurality of cells, or a spent battery in a pack unit including a plurality of modules. The spent battery may include a normal module having a voltage of about 2.0 to 4.5 V on a cell basis and a defective module that is short-circuited and thus difficult to measure the voltage.

In the step of preparing the waste battery, if the waste battery is a pack unit including the plurality of modules or has two or more modules, a step of measuring an average charge and discharge rate by measuring a charge and discharge rate of the waste battery may be included. Specifically, the step of measuring the average charge and discharge rate by measuring the charge and discharge rate of the waste battery may be performed using a constant-voltage discharge (CVD) or a constant-current discharge (CDC) so that charging and discharging are performed uniformly. For a plurality of modules arranged in the pack, if the time taken to charge and discharge the entire pack is divided by the number of modules, the average charge and discharge time of the modules can be calculated.

After the step of measuring the charge and discharge rates of a waste battery having a pack unit including a plurality of modules or two or more modules to measure an average charge and discharge rate, the waste battery in the pack unit can be disassembled into module units. Specifically, it can be a preprocessing step for disassembling the waste battery in the pack unit arranged into a plurality of module units to calculate the charge and discharge rate of each module.

A step is included in which the spent batteries in the above-mentioned pack unit are disassembled into modules, and then the charging and discharging speeds are measured for each module, and the charging and discharging times of the spent batteries in the above-mentioned module unit are measured and compared with the average charging and discharging time. Specifically, it may be a step of comparing the charging and discharging times of a plurality of the spent batteries in the above-mentioned module unit with the average charging and discharging time of the spent batteries in the above-mentioned pack unit.

It can be determined whether the average charge and discharge time of a waste battery having a pack unit including a plurality of modules or two or more modules and the charge and discharge time of the waste battery in the module unit satisfy the following Equation 1. Specifically, if the average charge and discharge time of a waste battery having a pack unit including a plurality of modules or two or more modules and the charge and discharge time of the waste battery in the module unit satisfy the following Equation 1, it can be determined as a normal module, and if it does not satisfy Equation 1, it can be determined as a short-circuited module in which a short circuit occurs and charging and discharging are not performed smoothly.

<Formula 1>

(In the above equation 1, t _aver means the average charge and discharge time of a pack unit including multiple modules or the number of waste batteries per module unit having two or more modules, and t _module means the charge and discharge time of a waste battery per module unit/the number of cells.)

Satisfying the above equation 1 means that the difference between the average charge and discharge time of the waste battery in the pack unit and the charge and discharge time of the waste battery in the module unit is divided by the average charge and discharge time of the waste battery in the pack unit, which is less than the fraction of the number of cells in the waste battery in the module unit, and this can be an indicator of determining that the module is normal. In contrast, not satisfying the above equation 1 means that the difference between the average charge and discharge time of the waste battery in the pack unit and the charge and discharge time of the waste battery in the module unit is greater than the fraction of the number of cells in the waste battery in the module unit, which means that at least one of the cells in the module is defective due to a short circuit, etc.

In this way, the present invention measures the charging and discharging speed of a waste battery to calculate the charging and discharging time, thereby easily determining whether a module in the waste battery is normal or defective.

In one embodiment, the step of electrically discharging a normal module satisfying the above formula 1 to 0.1 V or less may be included. Specifically, the normal module satisfying the above formula 1 is a module whose voltage may be lowered by electrical discharge, and the voltage of the module may be lowered to 0.1 V or less, specifically, 0.8 V or less, and more specifically, 0.5 V or less, based on a cell, by performing electrical discharge. When the normal module is electrically discharged within the above-described range, sparks do not occur and smoke or fire do not occur in the post-process step of crushing cells, so that the process can be performed safely. In contrast, when it is outside the above-described range, a safety issue may be caused in performing the process.

In one embodiment, a defective module that does not satisfy the above equation 1 may include a step of freezing. The defective module is a module that has a problem such as a short circuit, and has a problem in that the reference voltage of the cells within the module cannot be lowered through electric discharge. By freezing the defective module, the module can be easily discharged without generating waste water like a salt water discharge.

In one embodiment, the step of freezing the defective module can be performed at 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 an electrolyte included in the battery. Specifically, the step of freezing the defective module can be performed at a temperature range of, for example, -150 to -20° C. More specifically, the temperature range can be performed at a temperature range of -150 to -50° C., and more specifically, -80 to -60° C.

When the above-mentioned defective module is frozen in the above-mentioned temperature range, the voltage remaining slightly inside the battery, for example, about 2 V to 3 V, is lowered to close to 0 V, so that even if a short circuit occurs in which the positive and negative electrodes are in direct contact, a battery reaction does not occur, so the battery temperature does not increase, and gas generation and combustion of the electrolyte do not occur. In addition, since the electrolyte is in a frozen state or a state in which vaporization is suppressed, the mobility of lithium ions is very low, so that the conduction characteristics according to the movement of lithium ions can be significantly reduced, and since vaporization of the electrolyte does not occur, flammable gases such as ethylene, propylene, and hydrogen can not be generated.

If the above freezing process is outside the above temperature range, the voltage remaining inside the battery may not be lowered to 0 V, which may cause a battery reaction due to a short circuit, and the electrolyte may not be completely frozen, which is not appropriate. In this way, the battery processing method includes a step of freezing a defective module before crushing a battery such as a lithium secondary battery, thereby having the advantage of easily discharging a defective module that is difficult to discharge electricity, thereby preventing the risk of fire that may occur during the battery crushing process.

In one embodiment, the step of freezing the defective module can be performed for 15 to 36 hours. The step of freezing the defective module can be performed for 20 to 30 hours, specifically, 22 to 27 hours. Since the step of freezing the defective module is performed within the above-described time range, battery stabilization can easily proceed, and when the battery is shredded, a fire can be prevented from occurring from the battery.

If the step of freezing the above-mentioned defective module takes excessively longer than the above-mentioned time, there is a problem of uneconomical efficiency. If the step of freezing the above-mentioned defective module is performed for excessively shorter than the above-mentioned time, there is a problem of battery stabilization not being easily performed.

In one embodiment, the battery processing method may include a step of grounding the normal module after the step of discharging the electric charge. Specifically, the (+) pole and the (-) pole of the waste battery, for example, the module, which has performed the electric discharge, may be grounded to continuously maintain the discharge state. By including the step of grounding, the voltage of the waste battery may be prevented from being recovered by 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.

In one embodiment, the battery processing method may include a step of crushing the normal module that has performed the electric discharge or the defective module that has performed the freezing step. Specifically, it may refer to a process of applying an impact or pressure to the battery so that a part of the battery falls off from the battery, which is a normal module that has performed the electric discharge or a defective module that has performed the freezing step. The step of crushing the normal or defective module may refer to a process of crushing the battery, a process of cutting the battery, a process of compressing the battery, and any combination thereof. Specifically, the step of crushing may include any process that can destroy the battery, which is a normal or defective module, to obtain small-sized fragments.

In one embodiment, the step of crushing the normal or defective module may include any process of compressing the battery, which is the normal or defective module, or applying an external force, such as a shear force or a tensile force, to destroy the battery. The step of crushing the normal or defective module may be performed, for example, using a crusher.

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

In one embodiment, the step of crushing a normal or defective module can be performed 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. Since the step of crushing a normal or defective module is performed under the aforementioned gas atmosphere, the process can be performed safely compared to when performed in the atmosphere.

In one embodiment, the step of crushing the normal or defective module can be performed in an atmosphere having an oxygen concentration of 3%% or less. Specifically, the step of crushing the normal or defective module can have an oxygen concentration of 3% or less by volume, more specifically, 0.1% or less. In one embodiment, the step of crushing the normal or defective module can be performed within 6 hours.

In the above crushing step, if the concentration of the oxygen satisfies the above-mentioned range, the safety problem in the process can be solved, and if the concentration of the oxygen is excessively high, exceeding 6%, there is a problem that a fire may occur by reacting with the electrolyte when a spark occurs in the waste battery.

In one embodiment, after the step of crushing the normal or defective module, a step of drying the crushed result at a temperature of 200° C. or lower may be included. The drying step may be a step for removing the electrolyte within the crushed result.

In one embodiment, the drying step may utilize hot air. Specifically, hot air using gas may be applied to the crushed result to remove the electrolyte within the crushed result.

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. By using an inert gas as the gas for the hot air, there is an advantage in terms of fire prevention.

In one embodiment, the drying step may be performed in an atmosphere having an oxygen concentration of 5% or less. By ensuring that the oxygen concentration in the drying step satisfies the above-described range, the possibility of smoke or fire generation may be reduced. Specifically, some of the cut battery shreds may recover voltage over time, and at this time, smoke may be generated as they react with the electrolyte that has been evaporated. At this time, by performing the drying in the above-described oxygen concentration range, the possibility of smoke generation from the battery shreds may be significantly reduced.

In one embodiment, the drying step can be performed within 6 hours, specifically, within 4 hours. When the inert gas is used in the drying step, if the oxygen concentration is outside the above-mentioned range, a problem of reduced safety in performing the process may occur.

In one embodiment, the dried result obtained through the drying step may satisfy the following equation 2.

<Formula 2>

(In the above formula 2, w ₁ and w ₂ represent the initial weight (Kg) of the crushed result and the weight (Kg) of the dried result, respectively)

The above equation 2 refers to the weight change amount when the crushed result is dried, and may be an indicator of the volatilization of the electrolyte. The equation 2 may satisfy 10% or less, specifically, 2.0 to 8.0%, and more specifically, 3.8 to 7.8%. When the equation 2 satisfies the above-mentioned range, the electrolyte in the crushed result may be volatilized by 40% or more, thereby obtaining a post-stabilized crushed product. When the equation 2 is out of the above-mentioned range, the electrolyte may not be easily removed, which may cause safety issues or reduce process efficiency.

A battery processing method according to another embodiment of the present invention may provide a method for processing a module-based battery including a plurality of cells. The battery processing method may include a step of preparing a module-based waste battery including a plurality of cells, a step of measuring a charge and discharge rate of the module-based waste battery, a step of evaluating a temperature of a cell unit within the module, and a step of determining a normal module or a defective module based on whether a temperature deviation of the cell unit satisfies 3° C. or less.

The step of measuring the charge and discharge rates of the waste battery in the module unit including the plurality of cells can be performed in the same manner as the method of measuring the charge and discharge rates of the waste battery in the module unit in the battery processing method of the waste battery in the pack unit including the plurality of modules described above.

A normal module satisfying the above formula 3 may include a step of discharging electricity, a step of crushing, and a step of drying, similar to the method of processing a battery from a unit-of-pack waste battery described above. A defective module not satisfying the above formula 3 may include a step of freezing, a step of crushing, and a step of drying, similar to the method of processing a battery from a unit-of-pack waste battery described above, and a detailed description thereof may be referred to the above-mentioned contents within the scope that is not contradictory.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

<Experimental Example 1>: Method for judging and processing normal modules in a battery pack

Battery Preparation Steps

In the present invention, a battery module including a plurality of cells and a battery pack including a plurality of the modules are prepared.

Determining if there is a short circuit in the battery

The above battery pack was charged and discharged. At this time, when charging and discharging the battery, constant-voltage discharge (CVD) or constant-current discharge (CDC) was used to uniformly charge and discharge. Since multiple modules are arranged in the pack, when the time taken to charge and discharge the entire pack is divided by the number of modules, the average charge and discharge time of the modules is obtained. Thereafter, disassembly is performed for each module. After disassembly for each module, charging and discharging is performed for each module, and this is performed using the same value of constant-voltage discharge or constant-current discharge used in the pack.

At this time, if you divide the number of modules in the pack, you get the average charge/discharge time (taver) of the module. By comparing the charge/discharge speeds of the separated modules, you can determine which module has a short circuit if the charge/discharge speeds of the separated modules differ by more than a certain amount of time.

The average charge/discharge time (taver) and the specific time above were calculated using the following relationship.

<Average charge/discharge time (traver)>

<Specific time>

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 less than the fraction of the number of cells in the module, the module is judged to be normal. In the above formula, if the difference between the average charge/discharge time of the pack and the average discharge time of the module is greater than the fraction of the number of cells in the module, there is a high possibility that at least one cell is defective due to a short circuit, etc., and the module is judged to be defective.

Performing electrical discharge on a normal module

An electric discharge was performed on a normal module, where the above average charge/discharge and the above specific time satisfied the above-mentioned relationship. The electric discharge was performed several times to crush the cell according to the voltage, and whether sparks occurred and whether smoke and fire occurred were measured.

After discharge, the + and - poles of the module were grounded to ensure continuous discharge and prevent voltage recovery due to the standard reduction potential difference. At this time, the grounding standard was performed for more than 6 hours.

Table 1 below shows the results of measuring whether sparks occur and whether smoke or fire occurs according to voltage when performing an electric discharge.

The occurrence of sparks and the occurrence of smoke and fire were measured using the following methods.

Spark occurrence : Using a thermal imaging camera, check whether the temperature rises by more than 20 degrees when measuring. If the temperature is more than 20 degrees, a spark is indicated by ○, if it is between 10 and 20 degrees, it is indicated by △, and if the temperature does not rise below 10 degrees, a spark is indicated by ×.

Smoke and fire occurrence : Smoke and fire occurrence was confirmed by visually observing smoke or fire when performing an electric discharge. If smoke or fire occurred, it was marked with ○, and if no smoke or fire occurred, it was marked with ×.

number When discharging
voltage
[V] Spark
(Spark)
generation performance
generation fire
generation note Experimental example 4 ○ ○ ○ Comparative example Experimental example 3.5 ○ ○ ○ Comparative example Experimental example 3 ○ ○ × Comparative example Experimental example 2.5 ○ ○ × Comparative example Experimental example 2 ○ ○ × Comparative example Experimental example 1.5 ○ × × Comparative example Experimental example 1.0 ○ × × Comparative example Experimental example 0.8 △ × × Example Experimental example 0.5 × × × Example Experimental example 0.2 × × × Example Experimental example 0.1 × × × Example

Looking at Table 1 above, it was confirmed that when electric discharge was performed at a voltage lower than 1.0 V based on cells in a module with a series-parallel structure, no spark occurred, and when electric discharge was performed at a voltage lower than 2.0 V, no smoke occurred. Figures 2a and 2b are graphs of temperature rise before and after battery crushing.

Figure 2a is a graph of temperature rise before shredding, and Figure 2b is a graph of temperature rise when the battery is shredded. It was confirmed that no temperature rise occurred before the battery was shredded, and that a temperature rise peak occurred when a spark occurred during the battery shredding.

Battery shredding

The above battery was shredded using a shredder. At this time, since additional fire may occur inside the shredder, inert gases such as nitrogen, argon, and carbon dioxide were injected to maintain the oxygen content below 1 wt%. In addition, since the shredded material maintains the structure of the battery even when shredded, the size of the shredded material was adjusted to be within 100 mm based on the long axis of the shredded material.

Removal of electrolyte from shredded material

The above-mentioned shredded material was supplied with hot air to remove the electrolyte in the above-mentioned shredded material. The atmosphere or nitrogen (N ₂ ) gas, which is an inert gas, was used as the gas for the hot air. At this time, when the gas was the atmosphere, the oxygen concentration was maintained at about 21%, and when the gas was an inert gas, the oxygen concentration was maintained at 5% or less. Thereafter, whether smoke was generated was determined over time. At this time, the temperature of the hot air was set to 120°C, and drying was performed for 12 hours.

Table 2 below shows whether smoke is generated when hot air is supplied to the above-mentioned shredded material, depending on the atmospheric and inert gas conditions.

Smoke generation: Whether or not the shredded material generated smoke was determined by placing the shredded material on a rotatable table and slowly rotating it at 10 rpm for 4 hours. If smoke was generated, it was marked as ○. If no smoke was generated, but a burning smell or a mist was generated, it was marked as △. If no smell or mist was generated at all, i.e. no smoke was generated, it was marked as ×.

Processing time Whether smoke occurs Inert gas
(Oxygen content:
5% or less) atmosphere
(Oxygen content:
21%) 1 × × 2 × × 3 × ○ 4 × ○ 6 △ ○ 8 ○ ○ 12 ○ ○ 16 ○ ○ 20 ○ ○ 24 ○ ○ 48 ○ ○

Looking at Table 2 above, when hot air was applied to the shredded material, no smoke was generated when treated for less than 2 hours under atmospheric conditions, and no smoke was generated when treated for less than 6 hours under inert gas conditions, confirming that there was no risk of fire.

Weight measurement test of shredded material

Table 3 below shows the change in weight of the shredded material over time when nitrogen gas was used as hot air in the step of drying the electrolyte and the temperature of the hot air was set to 120°C. The weight of the shredded material was measured using the method below.

Weight of shredded material : The weight of the shredded material was measured using a scale. The initial weight is the weight of the shredded material measured within 1 minute after shredding in the pre-drying stage. The weight after drying is the weight of the shredded material after the hot air drying stage. The weight change rate is the change rate of the weight after drying calculated based on the initial weight of the shredded material.

Drying time Weight Measurement Test Rotation test note Initial weight
[Kg] After drying
weight
[Kg] Weight change rate
[%] Smoke generation 20 minutes 1.01 0.99 2 ○ Comparative example 30 minutes 1.02 1.00 1.9 ○ Comparative example 1 hour 1.05 1.1 3.8 × Example 1 hour and 30 minutes 1.01 0.97 3.9 × Example 2 hours 1.03 0.97 5.8 × Example 3 hours 1.02 0.96 5.9 × Example 4 hours 1.01 0.95 5.9 × Example 6 hours 1.03 0.96 6.8 × Example 12 hours 1.02 0.94 7.8 × Example

Looking at Table 2 above, it was confirmed that smoke was generated from the shredded material when the weight change rate of the shredded material had a value of 2% or less. However, it was confirmed that smoke was not generated when the weight change rate of the shredded material satisfied 3% or more. Since the weight specific gravity of the shredded material changed by about 6%, theoretically, the total electrolyte is included at a weight specific gravity of about 12 to 13%, it can mean that the electrolyte was reduced by 40% or more.

<Experimental Example 2>: Method for judging and handling defective modules in battery packs

In Experimental Example 1, a defective module was determined based on whether there was a short circuit inside the battery, and the defective module was frozen without a separate electric discharge. In the case of an internal short circuit, since discharge does not occur even if an electric discharge is performed, neutralization was performed by freezing. Specifically, the defective module was subjected to cryogenic treatment at -60°C for 24 hours.

Thereafter, the batteries that underwent cryogenic treatment were crushed using a general crusher, and the battery crushing step and the subsequent drying step were performed in the same manner as in Experimental Example 1. The freezing temperature during cryo-crushing varies depending on the charge amount of the waste battery. When the charge amount is 3 V or less based on the cell, the freezing temperature is -50 ° C or lower, and when it is 3.5 V or lower, it is -70 ° C or lower. When it is 3.5 V or higher, it is -90 ° C or lower.

After shredding, it is necessary to store it without rotating it in the stabilization system, and at this time, the temperature rises due to self-heating. The shredding condition of the shredded material is best within 10~50mm, and the average shredding size is best within 10~30mm. If it is larger, the risk of fire increases, and if it is smaller than 10mm, it is difficult to shred it because it gets caught between the shredding blades.

<Experimental Example 3>: Judgment and processing method for the battery module itself

In the step of preparing the battery of Experimental Example 1, a battery module including multiple cells, not a battery pack, was prepared. The battery module may be configured to have a parallel structure using two cells, or may be configured to have a parallel structure of three to four cells. This varies depending on the module design of the battery. When charging and discharging the battery, heat is generated due to the movement of charges. In the case of a case visible from the outside, a thermal imaging camera can find a short-circuited cell with only the temperature difference. During charging and discharging, the amount of heat generated increases based on the standard potential of the ternary battery at 2.5 V. Below 2.5 V, the internal structure deforms and the amount of heat generated increases.

Figure 1 is a drawing showing the temperature of the battery module itself of the present invention measured using a thermal imaging camera.

Referring to Figure 1, in the present invention, charging and discharging are distinguished separately, and when discharging, the temperature deviation between individual modules is measured using a thermal imaging camera with the external case removed. The figure below shows the temperature deviation in the module, and if there is a short circuit in the center, the temperature rise is slow. It was confirmed that there was an internal short circuit when the temperature deviation was 3℃ or more compared to the surroundings. It was confirmed that in most cases of normal cells, the temperature deviation occurred at 3℃ or less.

Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made 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 (20)

A step of preparing a pack unit including a plurality of modules or a waste battery having two or more modules; A step of measuring the charging and discharging speed of the above-mentioned waste battery to measure the average charging and discharging time; A step of measuring the charging and discharging speed of the module-based waste battery in the above waste battery, measuring the average charging and discharging time of the module-based waste battery, and comparing it with the average charging and discharging time; and A battery processing method comprising a step of determining a normal module or a defective module based on whether the average charge and discharge time of a waste battery having a pack unit including the plurality of modules or two or more modules and the charge and discharge time of the waste battery in module units satisfy the following Equation 1. <Formula 1>

(In the above equation 1, t _aver means the average charge and discharge time of a pack unit including multiple modules or the number of waste batteries per module unit having two or more modules, and t _module means the charge and discharge time of a waste battery per module unit/the number of cells.) In the first paragraph, A battery processing method comprising a step of electrically discharging a normal module satisfying the above formula 1 to 0.1 V or less. In the second paragraph, A battery processing method comprising a step of grounding the normal module after the above electric discharging step. In the second paragraph, A battery processing method comprising the step of crushing the normal module that has performed the above electric discharge. In the fourth paragraph, A battery processing method wherein the step of crushing the above normal modules is performed in an inert gas. In the fourth paragraph, A battery processing method wherein the step of crushing the above normal module is performed in an atmosphere having an oxygen concentration of 3% or less. In the third paragraph, After the step of crushing the above normal module, A battery processing method comprising a step of drying the crushed result at a temperature of 200° C or less. In Article 7, A battery processing method wherein the above drying step is performed in an atmosphere having an oxygen concentration of 5% or less. In the first paragraph, A method for processing a battery, comprising the step of freezing the defective module. In Article 9, A battery processing method in which the step of freezing the above defective module is performed at a temperature range of -20°C or lower. In the first paragraph, A step of measuring the average charge and discharge speed by measuring the charge and discharge speed of the above-mentioned waste battery is a battery processing method in which the above-mentioned waste battery is charged and discharged with a constant voltage or constant current. A step for preparing a waste battery in a modular unit including multiple cells; A step of measuring the charging and discharging speed of the above-mentioned waste battery; A step of evaluating the temperature of each cell within the module; and A battery processing method comprising a step of determining a normal module or a defective module based on whether the temperature deviation of the above cell unit is 3℃ or less. In Article 12, A battery processing method comprising the step of electrically discharging the above normal module to 0.1 V or less. In Article 13, A battery processing method comprising the step of crushing the normal module that has undergone the above electric discharge in an atmosphere having an oxygen concentration of 0.5% or less. In Article 14, After the step of crushing the above normal module, A battery processing method comprising a step of drying the crushed result at a temperature of 200° C or less. In Article 12, A method for processing a battery, comprising the step of cryo-crushing the defective module. A step of preparing a pack unit including a plurality of modules or a waste battery having two or more modules; A step of measuring the charging and discharging speed of the above-mentioned waste battery to measure the average charging and discharging time; A step of measuring the charge and discharge speed of a module-based waste battery in a pack unit including the plurality of modules or a waste battery having two or more modules, thereby measuring the charge and discharge time of the module-based waste battery and comparing it with the average charge and discharge time; A step for determining whether the above module unit waste battery is a normal module or a defective module; A step of crushing the above normal module or defective module; and Comprising a step of drying the above crushed result at a temperature of 200 ℃ or less, The above dried result is a battery processing method satisfying the following equation 2. <Formula 2>

(In the above formula 2, w ₁ and w ₂ represent the initial weight (Kg) of the crushed result and the weight (Kg) of the dried result, respectively) In Article 17, A battery processing method comprising a step of measuring the charge and discharge rates of each module and comparing them with the average charge and discharge rates to determine whether a module is normal or defective, wherein the step of determining whether the step satisfies the following Equation 1 is included. <Formula 1>

In Article 18, After the step of measuring the charge and discharge speed for each module and comparing it with the average charge and discharge speed, A battery processing method comprising a step of electrically discharging a normal module satisfying the above formula 1 to 0.1 V or less. In Article 17, After the step of measuring the charge and discharge speed for each module and comparing it with the average charge and discharge speed, A battery processing method in which the step of freezing a defective module that does not satisfy the above formula 1 is performed in a temperature range of -20°C or less.

Images