Unit battery shredded material, battery shredded material including same, and battery processing method

Abstract

The present invention relates to a unit battery shredded material, a battery shredded material including same, and a battery processing method. The unit battery shredded material is for recovering valuable metal from a waste battery, wherein the unit battery shredded material has a layered structure including a separation film in which a cathode or an anode is stacked on at least one surface thereof, and satisfies conditions 1 to 3 in the present specification.

Description

Unit battery shredder, battery shredder containing the same, and method for processing batteries

[0001] The present invention relates to waste batteries, and to unit battery shreds extracted from waste battery recycling, battery shreds including the same, and a method for processing batteries.

[0002] As global demand for electric vehicles grows, the disposal of waste batteries generated from these vehicles is emerging as a social issue. Lithium secondary batteries, the primary raw material for these waste batteries, contain organic solvents, explosive materials, and heavy metals such as nickel, cobalt, manganese, and iron. However, nickel, cobalt, manganese, and lithium are valuable metals with high scarcity value. Therefore, the recovery and recycling processes for discarded lithium secondary batteries are emerging as a key research area.

[0003] Specifically, a lithium secondary battery is mainly composed of copper and aluminum used as a current collector, Li, Ni, Co, Mn containing oxides constituting a positive electrode material, and graphite used as an negative electrode material, and includes a separator separating the positive electrode material and the negative electrode material, and an electrolyte injected into the separator. The solvent and salt used as the electrolyte are mainly a mixture of carbonate organic substances such as ethylene carbonate and propylene carbonate, and LiPF6 is used as a representative salt.

[0004] In order to utilize the above-mentioned waste batteries, development is actively underway on a waste battery recycling process that crushes the waste batteries to produce intermediate materials such as waste battery shreds or black powder, and then recovers valuable metals through a post-process.

[0005] However, in the waste battery recycling process, the waste battery generally has a voltage in the range of 3.0 to 3.2 V in a fully discharged state per cell, although this voltage varies depending on the number of times the battery has been used or its condition, and has a voltage close to 4 V in a fully charged state. Therefore, in a module or pack in which tens to hundreds of cells are connected, the residual voltage has a considerable amount of energy, so when an external shock is applied to the waste battery to physically disassemble it, safety related to explosion or electric shock of the battery becomes a problem.

[0006] To prevent this, after disassembly, a hole is created in the battery and it is discharged in salt water. After the discharge is complete, the battery is shredded and subjected to high-temperature heat treatment to remove water and electrolyte.

[0007] At this time, the salt used in the brine discharge contains a large amount of substances such as Na, K, Cl, Mg, and Ca. Among the substances mentioned above, Cl in particular is partially removed during the high-temperature heat treatment process, but the black powder, which is a powder in the form of a mixture of Ni-Co-Mn-Li-O oxide and C obtained by further processing the shredded or shredded waste battery to remove Al, Cu, and a portion of the separator, contains impurities such as Na, K, and Mg, which causes a problem of reducing the recovery rate during the extraction process using acid leaching in the subsequent process of the battery recycling process.

[0008] In addition, research is needed on a post-processing method to remove the electrolyte contained in the shredded material in order to stably transport it to the post-processing stage after shredding the used batteries.

[0009] According to one embodiment of the present invention, through recycling of waste batteries, a unit battery shredder having a low impurity content and preventing fire occurrence is provided.

[0010] According to one embodiment of the present invention, the battery shredder has the advantages described above and comprises at least one unit battery shredder.

[0011] In another embodiment of the present invention, a method for processing a battery provides a method for producing battery shredder having the aforementioned advantages by removing volatile materials.

[0012] In one embodiment, the unit battery shredder is a unit battery shredder for recovering valuable metals from a spent battery, wherein the unit battery shredder has a layered structure including a separator having a positive electrode or a negative electrode laminated on at least one surface, and can satisfy the following conditions 1, 2, and 3.

[0013] <Condition 1> The above layered structure is a laminated structure having 1 or more layers and 7 or fewer layers.

[0014] <Condition 2> The size of the unit battery shreds based on the longest axis among the horizontal, vertical, and height directions is 100 mm or less.

[0015] <Condition 3> When the above unit battery shreds are reheated at 150°C, the weight of the above unit battery shreds decreases by 1.0% or less.

[0016] In one embodiment, the surface of the unit battery shredder includes a burnt region, which is an area where at least a portion of the surface is burned, and a top region on the surface where there are no burn marks, and the area ratio of the burnt region to the top region may be 30% or less. In one embodiment, the burnt region may be formed at an edge portion of the surface.

[0017] According to another embodiment of the present invention, the battery shredder is a unit battery shredder for recovering valuable metals from waste batteries,

[0018] The above unit battery shredder comprises at least one unit battery shredder having a layered structure including a separator with a positive or negative electrode laminated on at least one surface, and satisfying the following conditions 1, 2, and 3.

[0019] <Condition 1> The above layered structure is a laminated structure having 1 or more layers and 7 or fewer layers.

[0020] <Condition 2> The size of the unit battery shreds based on the longest axis among the horizontal, vertical, and height directions is 100 mm or less.

[0021] <Condition 3> When the above unit battery shreds are reheated at 150°C, the weight of the above unit battery shreds decreases by 1.0% or less.

[0022] In one embodiment, the content of the unit battery shredder may be 90% or more of the total volume of the battery shredder. In one embodiment, the unit battery shredder may include impurities of Na: 0.4% or less, Ca: 0.03% or less, Mg: 0.02% or less, and K: 0.02% or less, in wt%.

[0023] According to another embodiment of the present invention, a battery processing method comprises the steps of freezing a battery, crushing the frozen battery into battery shreds, and stabilizing the crushed battery shreds, wherein the battery shreds include at least one unit battery shred, and the unit battery shreds have a layered structure including a separator having a positive electrode or a negative electrode laminated on at least one surface, and satisfies the following conditions 1 and 2, and the stabilizing step may satisfy the following condition 5.

[0024] Condition 1

[0025] The above layered structure is a laminated structure having 1 or more layers and 7 or fewer layers.

[0026] Condition 2

[0027] The size of the unit battery shreds based on the longest axis among the horizontal, vertical, and height directions is 100 mm or less.

[0028] Condition 5

[0029] Low-temperature stabilization treatment is performed at 30°C or lower, and after the low-temperature stabilization treatment, high-temperature stabilization treatment is performed at 30°C or higher to 150°C.

[0030] In one embodiment, the weight of the battery shreds may be reduced by 2.8 to 4.6% in the low-temperature stabilization treatment step compared to the weight of the battery shreds before the low-temperature stabilization treatment step. In one embodiment, the weight of the battery shreds may be reduced by 8 to 10% in the high-temperature stabilization treatment step compared to the weight of the battery shreds before the low-temperature stabilization treatment step.

[0031] In one embodiment, the battery shredder may satisfy the following condition 4.

[0032] Condition 4

[0033] The tap density of the above battery shredder is 200 to 600 kg / m 3 am

[0034] In one embodiment, the low-temperature stabilization time in the low-temperature stabilization treatment may be 6 to 12 hours. In one embodiment, the high-temperature stabilization time in the high-temperature stabilization treatment may be 5 to 12 hours.

[0035]

[0036] In one embodiment, the stabilization treatment may be performed at a temperature of 0 to 150° C. applied to the shredded material. In one embodiment, a battery processing method including an intermediate stabilization treatment step prior to the high-temperature stabilization treatment step, wherein the intermediate stabilization treatment step may be performed at a temperature of 30 to 120° C.

[0037] In one embodiment, the intermediate stabilization treatment step is performed by a multi-stage heat treatment, and the multi-stage heat treatment may be performed sequentially at a first temperature of 30 to 60° C., a second temperature of 60 to 90° C., and a third temperature of 90 to 120° C. In one embodiment, the shredding step may include a step of controlling the proportion of the unit battery shreds to be 90% or more of the total volume of the battery shreds.

[0038] In one embodiment, the freezing step may be performed by cooling to -150°C to -20°C. In one embodiment, the freezing step may be performed by cooling to -60°C to -20°C, and the crushing step may be performed under vacuum conditions of 100 torr or less.

[0039] According to one embodiment of the present invention, the unit battery shredder includes low-temperature and high-temperature stabilization treatment steps at predetermined temperatures, thereby providing a unit battery shredder having a low impurity content and preventing fire occurrence.

[0040] In another embodiment of the present invention, the battery shredder provides a battery shredder having at least one unit battery shredder having the advantages described above.

[0041] According to another embodiment of the present invention, a battery processing method provides a method for producing battery shreds having the aforementioned advantages by controlling the weight reduction amount of the battery shreds by performing low-temperature and high-temperature stabilization treatment steps on the battery shreds at predetermined temperatures.

[0042] Figure 1 shows the change in voltage of a battery according to cooling temperature according to one embodiment of the present invention.

[0043] FIG. 2 is a graph showing the relationship between battery weight, external cooling temperature, and cooling time according to one embodiment of the present invention.

[0044] Figures 3a and 3b are photographs of an example according to the minimum cooling time of the present invention, and Figures 3c and 3d are photographs of a comparative example according to the minimum cooling time of the present invention.

[0045] Figure 4 is a graph of temperature over time of a shredded material according to one embodiment of the present invention.

[0046] FIG. 5a illustrates a unit battery shredder according to one embodiment of the present invention and a comparative example, FIG. 5b illustrates a mixing ratio according to a weight ratio of the battery shredder according to one embodiment of the present invention, and FIG. 5c illustrates a combustion section and a top section of the surface of the unit battery shredder.

[0047] Figures 6a to 6c are photographs showing the temperature measurement process of a waste battery and the temperature trend of the shredded material according to the SOC conditions.

[0048] Figure 7 is a graph showing the temperature increase trend of the shredded material according to the SOC % condition of the battery.

[0049] FIG. 8 is a graph showing the temperature of battery shreds over time in low-temperature stabilization, intermediate stage, and high-temperature stabilization stages according to one embodiment of the present invention.

[0050] Figure 9a is a schematic diagram of a stabilization device for performing a battery stabilization step, and Figure 9b is a graph showing self-heating of battery shreds inside a transport container.

[0051] Figure 10 shows the temperature change of the crushed material when the heating temperature was controlled for each section for heat treatment in the high-temperature stabilization stage.

[0052] Figure 11 shows the weight reduction ratio (%) of the electrolyte in the shredded battery according to the heat treatment temperature of 150°C after high-temperature stabilization treatment of the shredded battery.

[0053] Figure 12 shows the temperature and weight reduction according to the tap density of the battery shredder.

[0054] 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 used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, 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.

[0055] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0056] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0057] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0058] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and the present invention is not limited thereto, and the present invention is defined solely by the scope of the claims set forth below.

[0059] According to one embodiment of the present invention, the unit battery shredder is for recovering valuable metals from waste batteries, and has a layered structure including a separator on which a positive electrode or a negative electrode is laminated on at least one surface. Specifically, the layered structure may include a configuration in which the positive electrode or the negative electrode is included on one or both surfaces of the separator based on the separator. More specifically, the number of layers of the layered structure may correspond to the number of separators.

[0060] The above layered structure includes, for example, any one of anode-separator-cathode, anode-separator, separator-anode, separator-cathode, and cathode-separator, and for example, anode-separator-cathode-separator-anode-separator-cathode may have a three-layered layered structure. Specifically, the unit battery shredder may have a predetermined thickness in the thickness direction as at least one or more layers are laminated.

[0061] In one embodiment, the unit battery shredder may satisfy the following condition 1.

[0062] <Condition 1> The above layered structure may be a laminated structure having 1 or more layers and 7 or fewer layers.

[0063] The above-mentioned unit battery shredder may have a layered structure having a laminated structure of one or more layers and no more than seven layers. Specifically, the layered structure may have a layered structure of one or more layers and no more than five layers. As the layered structure is laminated within the above range, the temperature rise of the shredder can be minimized and the heating time can be appropriately taken. If the layered structure is laminated thicker than the upper limit of the above range, the temperature rise excessively increases and the heating time also increases, which may cause a fire due to combustion.

[0064] In one embodiment, the unit battery shredder may satisfy the following condition 2.

[0065]

[0066] <Condition 2> The size of the above unit battery shreds may be 100 mm or less based on the longest axis among the horizontal, vertical, and height directions.

[0067] In one embodiment, the unit battery shredder may have a size of 100 mm or less based on its longitudinal axis. Specifically, the size of the unit battery shredder may be 50 mm or less. If the size of the unit battery shredder is excessively large, there is a problem that the temperature of the battery shredder itself may rise above 100°C, which increases the possibility of a fire occurring.

[0068] In one embodiment, the unit battery shredder may satisfy the following condition 3.

[0069] <Condition 3> When the above unit battery shreds are reheated to 150°C, the weight of the above unit battery shreds is reduced to 1% or less.

[0070] The above condition 3 may be an indicator of whether the unit battery shreds have undergone low-temperature and high-temperature stabilization steps. Specifically, when the unit battery shreds are reheated at 150°C and cooled, the weight of the battery shreds before heating and the weight of the battery shreds after heating may be compared, and the weight of the battery shreds after heating may be reduced by 1% or less compared to the weight of the battery shreds before heating.

[0071] If the weight of the above unit battery shreds satisfies the above-mentioned range, the low-temperature stabilization treatment and high-temperature stabilization treatment of the present invention can be performed, thereby providing safe unit battery shreds that can reduce the possibility of fire occurring in a subsequent process. If the weight of the above unit battery shreds exceeds the above-mentioned range, there is a problem that a fire occurs in a subsequent process because the electrolyte in the unit battery shreds does not easily volatilize.

[0072] In one embodiment, the surface of the unit battery shredder may include a burnt portion and a top portion. The burnt portion refers to an area where at least a portion of the surface of the unit battery shredder is burned, and the top portion refers to a top portion of the surface where there are no traces of combustion.

[0073] In one embodiment, the area ratio of the combustion portion to the top portion on the surface of the unit battery shredder may be 30% or less. By satisfying the area ratio of the combustion portion to the top portion to be 30% or less, the possibility of the unit battery shredder burning and causing a fire can be prevented. If the area ratio of the combustion portion to the top portion exceeds 30%, there is a risk that the unit battery shredder will burn and cause a fire accompanied by smoke.

[0074] In one embodiment, on the surface of the unit battery shredder, the combustion portion may be positioned at an edge of the surface. The top portion may be positioned near the center of the surface of the unit battery shredder. The combustion portion refers to an area that exhibits a darker color compared to the top portion.

[0075] In another embodiment of the present invention, the battery shredder may include at least one of the aforementioned unit battery shredders. In one embodiment, the battery shredder may comprise at least 90% of the total volume of the at least one unit battery shredder. Specifically, the content of the unit battery shredder may be at least 95% of the total volume of the battery shredder.

[0076] Specifically, the battery shredder may correspond to the content that the proportion of unit battery shredders having a laminated structure exceeding 7 layers may be 10% or less, specifically 5% or less, in the total volume of the battery shredder, or the proportion of at least one unit battery shredder having a size exceeding 100 mm in the long axis may be 10% or less, specifically 5% or less, in the total volume of the battery shredder.

[0077] In this way, the proportion of battery shreds having a layered structure exceeding 7 layers per unit volume within the entire volume of battery shreds or the proportion of unit battery shreds having a size exceeding 100 mm in terms of the long axis satisfies the above range, thereby preventing fire from occurring.

[0078] In one embodiment, the battery shredder is recovered from a waste battery and includes impurities, which may include, in weight percent, Na, Ca, Mg, and K. The battery shredder may be a shredder residue or black powder produced through a process of recovering and crushing the waste battery, which is a pretreatment process of a waste battery recycling process.

[0079] The above battery shredder may contain impurities such as Na, Ca, Mg, and K. The battery shredder may facilitate the extraction of Li, a cognate valuable metal, in a post-process by reducing the content of the impurities.

[0080] According to one embodiment of the present invention, the battery shredder includes impurities, and the impurities may include, in wt%, Na: 0.4% or less (excluding 0%), Ca: 0.03% or less (excluding 0%), Mg: 0.02% or less, and K: 0.02% or less.

[0081] Below, the reasons for limiting the content of the above impurities are explained.

[0082]

[0083] Na: 0.4 wt% or less (excluding 0%)

[0084] Sodium (Na) is a homologous element in the post-process of recovering valuable metals from the above-mentioned battery scrap, and has the side effect of lowering the recovery of lithium or increasing the cost in the causticization process by partially reacting sodium instead of lithium in the lithium hydroxide formation process to form sodium hydroxide. The above-mentioned battery scrap may contain 0.4 wt% or less of the sodium, and specifically, may contain 0.1 wt% or less of the sodium.

[0085] When the above sodium is contained in an amount greater than the above range, there is a problem that the yield decreases in the process required to produce lithium carbonate as Na is a Group 1 element identical to Li in the crystallization process of Li dissolved in the solvent after the leaching process and solvent extraction process when Na increases.

[0086]

[0087] Ca: 0.03 wt% or less (excluding 0%)

[0088] Calcium (Ca), like sodium, is an element that lowers the recovery rate of valuable metals in the post-processing of recovering valuable metals from the battery shredder. Calcium is more reactive than aluminum when forming lithium aluminate, forming a lithium cassinate structure, thereby hindering the formation of lithium aluminate, which is advantageous for subsequent reactions, thereby lowering the final lithium recovery rate. The battery shredder may contain 0.03% or less of calcium, and specifically, may contain 0.02% or less of calcium by weight.

[0089] If the above calcium is contained in an amount greater than the above range, there is a problem that the yield and process time increase during the solid-liquid separation process, which is an impurity purification process after the leaching process, as Ca increases. In addition, if the content of the above calcium is excessively large, when nickel, cobalt, manganese hydroxide and lithium hydroxide, which are precursors, are synthesized to produce a cathode material, Li[NiCoMn] 1-x Ca x )]O2, the potassium forms a cathode oxide structure, which hinders the movement of lithium ions, resulting in a problem of reduced battery capacity.

[0090]

[0091] Mg: 0.02 wt% or less

[0092] Magnesium (Mg) is an element that makes it difficult to separate solid and liquid phases during acid leaching in a metal recovery process. The battery waste may contain 0.02 wt% or less of magnesium, specifically, 0.01 wt% or less.

[0093] If the magnesium content is higher than the above range, there is a problem of burdening the recovery process of nickel, cobalt, lithium, etc. In addition, if the magnesium content is excessively high, when producing a cathode material by synthesizing with precursors such as nickel, cobalt, manganese hydroxide, and lithium hydroxide, Li[NiCoMn] 1-x Mgx ) is synthesized with O2, forming a cathode oxide structure, which hinders the movement of lithium ions and reduces the capacity of the battery.

[0094]

[0095] K: 0.02 wt % or less

[0096] Potassium (K), also a cognate element with lithium, acts to inhibit lithium from forming hydroxide compounds. The battery waste may contain potassium in an amount of 0.02 wt% or less, specifically, 0.01 wt% or less. If potassium is present in an amount greater than the above range, it can cause a load on the causticization process, thereby reducing the lithium recovery rate.

[0097]

[0098] According to another embodiment of the present invention, a battery processing method comprises the steps of freezing a battery, crushing the frozen battery, and stabilizing the crushed battery. The battery processing method may be a method for processing various types of batteries containing lithium ions, and the batteries may be, for example, lithium secondary batteries separated from automobiles, secondary battery batteries separated from electronic devices such as mobile phones, cameras, and laptops, and specifically, lithium secondary batteries.

[0099] In one embodiment, the step of freezing the battery may satisfy the following equation 1.

[0100] <Formula 1>

[0101] Minimum cooling time (Hr) = A × (W 0.33 )

[0102] (A = 4 × e(-0.02×dT), W = battery weight (Kg), dT= │external cooling temperature - target temperature│, ││ represents the absolute value)

[0103] In the above equation 1, W represents the weight of the battery, for example, the weight of a battery pack, a single battery, or a combination thereof. The minimum cooling time refers to the external cooling temperature, which is the cooling temperature applied to the battery, for example, the target temperature for cooling the electrolyte within the battery.

[0104] The step of freezing the battery has the advantage of allowing the electrolyte inside the battery to be cooled for a period longer than the minimum cooling time, thereby stably performing subsequent processes. However, if the step of freezing the battery is performed for a period shorter than the minimum cooling time, the electrolyte may not be cooled, which may lead to a risk of fire when crushed.

[0105] The step of freezing the battery is performed at a temperature sufficient to freeze the electrolyte contained within the battery. Specifically, the step of freezing may be performed at 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.

[0106] When the battery is frozen in the above temperature range, the voltage remaining slightly inside the battery, for example, about 2 V to 3 V, is lowered to close to 0 V, and even if a short circuit occurs in which the positive and negative electrodes are in direct contact, no battery reaction occurs, 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 in 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.

[0107] If the above freezing process is outside the above temperature range, for example, if it cools to a temperature higher than -60℃, the voltage remaining inside the battery will not be lowered to 0 V, so a battery reaction due to a short circuit may occur, and the electrolyte will not be completely frozen, which is not appropriate. In addition, if it is cooled to -150℃, the electrolyte is sufficiently frozen, and the voltage inside the battery will also be lowered to 0 V, so there is no need to lower the temperature below this. In this way, the battery processing method has the advantage of preventing the risk of fire that may occur during the battery crushing process by including a freezing step before crushing a battery such as a lithium secondary battery.

[0108] The step of shredding the frozen battery may refer to a process of applying shock or pressure to the battery so that a portion of the battery detaches from the battery. In one embodiment, the step of shredding the battery may refer to a process of crushing the battery, a process of cutting the battery, a process of compressing the battery, or a combination thereof. Specifically, the step of shredding may include any process that can destroy the battery to obtain small-sized shredded materials.

[0109] In one embodiment, the step of crushing the battery may include any process that destroys the battery by compressing the frozen battery or applying an external force, such as a shear force or a tensile force. The step of crushing the battery may be performed, for example, using a crusher.

[0110] In one embodiment, the step of crushing the battery may be performed at least once. Specifically, the step of crushing may be performed at least once, either continuously or discontinuously.

[0111] In one embodiment, the step of crushing the battery can be performed under conditions of supplying an inert gas, carbon dioxide, nitrogen, water, or a combination thereof, or under vacuum conditions of 100 torr or less. For example, when the process of freezing the battery is performed by cooling it in a temperature range of -60 to -20°C, when performed under the above-described conditions, the supply of oxygen can be suppressed, preventing the electrolyte from reacting with oxygen, thereby preventing an explosion caused by this, and the vaporization of the electrolyte can be suppressed, thereby preventing the generation of flammable gases such as ethylene, propylene, or hydrogen.

[0112] In one embodiment, at least one of the unit battery shreds included in the battery shreds may satisfy the following condition 1.

[0113] Condition 1

[0114] The above layered structure may have one or more layers and seven or fewer layers.

[0115] The above condition 1 may mean that the layered structure of the unit battery shredder including a separator with a positive or negative electrode laminated on at least one surface is controlled in the step of shredding into a layered structure of 1 or more layers and 7 or fewer layers.

[0116] In one embodiment, the layered structure may be a laminated structure having 1 to 7 layers. Specifically, the layered structure may be a laminated structure having 1 to 5 layers. As the layered structure is laminated within the above range, the temperature rise of the shredded material can be minimized and the heating time can be appropriately taken. If the layered structure is laminated thicker than the upper limit of the above range, the temperature rise excessively increases and the heating time also increases, which may cause combustion.

[0117] In one embodiment, at least one of the unit battery shreds included in the battery shreds may satisfy the following condition 2.

[0118] Condition 2

[0119] The size of the unit battery shreds may be 100 mm or less based on the long axis, which is the longest axis among the horizontal, vertical, and height directions.

[0120] In one embodiment, the size of the unit battery shreds, specifically, the longest axis among the horizontal, vertical, and height directions, may be controlled in the shredding step to be 100 mm or less, specifically 50 mm or less. If the maximum size of the battery shreds is greater than 100 mm, the heat generation temperature caused by instability as the battery shreds are shredded may rise to a temperature range of 120°C, which is the average vaporization temperature of the electrolyte, which may cause stability problems such as fire.

[0121] In one embodiment, at least one of the unit battery shreds included in the battery shreds may satisfy the following condition 4.

[0122] Condition 4

[0123] The tap density of the above-mentioned shredded battery waste is 200 to 600 kg / m 3 am.

[0124] The above tap density usually refers to the apparent density obtained by mechanically tapping a measuring container containing a powder sample. Specifically, in order to determine the tap density characteristics of the lithium-ion battery shredder, a commercial battery module consisting of about 30 cells weighing 30 kg was crushed with a crusher, placed in a case (volume: 0.44 m wide × 0.7 m long × 0.5 m high) manufactured to stabilize the shredder, and mechanically tapped to measure the apparent density. More specifically, the density (ρ = M / V) was obtained by dividing the battery weight (M, kg) by the case volume (V, m3). The tap density of the unit battery shredder calculated by the above-described method was 200 to 600 kg / m 3 Specifically, the tap density is 200 to 300 kg / m 3 It could be.

[0125] If the tap density exceeds the upper limit, there is a risk of fire due to the instantaneous generation of heat by the short circuit of the densely stacked pieces of shredded material, and there is a problem of reduced stabilization processing capacity due to the narrow space through which the electrolyte can escape to the outside. If the tap density exceeds the lower limit, there is a problem of many gaps being created between the shredded material and the material taking up a large volume, requiring an additional pressurization process to transport it to the subsequent process.

[0126] In one embodiment, the step of shredding the battery may further include a step of controlling the proportion of the unit battery shreds to be 90% or more, specifically 95% or more, of the total volume of the battery shreds. Specifically, this may correspond to controlling the proportion of the unit battery shreds having a laminated structure exceeding 7 layers to be 10% or less of the total volume of the battery shreds. Specifically, the proportion of the unit battery shreds having a laminated structure exceeding 7 layers may be controlled to be 5% or less of the total volume of the battery shreds. By satisfying the above range, there is an advantage in that the occurrence of a fire can be prevented.

[0127] In one embodiment, the step of stabilizing the shredded battery fragments may satisfy the following condition 5.

[0128] Condition 5

[0129] Low-temperature stabilization treatment is performed at 30°C or lower, and high-temperature stabilization treatment is performed at 120 to 150°C.

[0130] Specifically, the stabilizing step may include a low-temperature stabilization step and a high-temperature stabilization step performed at a higher temperature than the low-temperature stabilization step. The stabilizing step performs the low-temperature stabilization step and the high-temperature stabilization step simultaneously, thereby volatilizing the electrolyte within the shredded battery waste, thereby reducing the weight of the shredded battery waste and decreasing the tap density.

[0131] The above low-temperature stabilization step may be a step of stabilizing the crushed battery shreds at a temperature of 30°C or lower. Specifically, the low-temperature stabilization step may be a step of stabilizing the crushed battery shreds through self-heating. More specifically, the self-heating of the shreds varies depending on the condition of the SOC (State of Charge), which indicates the remaining capacity of the battery. More specifically, when the SOC is 30% or higher, sudden heat generation may occur, which may result in a fire. Therefore, the low-temperature stabilization step may be a preliminary step of stabilizing the battery at a temperature of 10°C or lower to minimize the aforementioned fire risk.

[0132] In one embodiment, the low-temperature stabilization treatment step may be performed for 6 to 12 hours. If the low-temperature stabilization treatment step is outside the upper limit of the aforementioned time range, the risk of fire is minimized, but there is a problem that the manufacturing lead time is extended and productivity is reduced. If the low-temperature stabilization treatment step is outside the lower limit of the aforementioned time range, the electrolyte may not be removed sufficiently safely, which may cause a problem of a fire occurring in a post-process. In one embodiment, the weight of the battery shredded material may be reduced by 2.8 to 4.6% during the low-temperature stabilization treatment step. Specifically, the weight of the battery shredded material may be reduced by 2.8 to 4.6% compared to the weight of the battery shredded material before the low-temperature stabilization treatment step. By reducing the weight of the battery shredded material within the aforementioned range through the low-temperature stabilization treatment, the low-temperature volatile electrolyte may be easily removed.

[0133] The above high-temperature stabilization treatment step may be performed at 120 to 150°C. Specifically, the high-temperature stabilization treatment step may be a step of applying high-temperature heat to the battery shreds stabilized through the low-temperature stabilization treatment step to volatilize the electrolyte within the battery shreds.

[0134] If the above-mentioned high-temperature stabilization treatment step exceeds the upper limit of the aforementioned temperature range, there is a risk of fire. If the above-mentioned high-temperature stabilization treatment step exceeds the lower limit of the aforementioned temperature range, there is a risk of the electrolyte within the battery shreds not being sufficiently volatilized.

[0135] In one embodiment, the high-temperature stabilization step may be performed for 6 to 12 hours. If the high-temperature stabilization step exceeds the upper limit of the aforementioned time range, productivity may be affected due to increased manufacturing lead times. If the high-temperature stabilization step exceeds the lower limit of the aforementioned time range, the electrolyte may not be sufficiently removed, potentially causing a fire in the subsequent process.

[0136] In one embodiment, the weight of the battery shreds may be reduced by 8 to 10% in the high-temperature stabilization treatment step compared to the weight of the battery shreds prior to performing the low-temperature stabilization treatment step. Specifically, by satisfying the aforementioned range in weight of the battery shreds, it can be confirmed that the high-temperature volatile electrolyte is easily volatilized.

[0137] For example, based on 100% of the battery's weight, the electrolyte may account for 10 to 15%. After the high-temperature stabilization treatment step is completed, approximately 60 to 70% of the electrolyte's weight is evaporated, which means a reduction of 9 to 10% based on the total 100% weight of the battery.

[0138] In one embodiment, an intermediate stabilization step may be included prior to the high-temperature stabilization step, and the time of the intermediate stabilization step may be included in the high-temperature stabilization time. The intermediate stabilization step may be a step for volatilizing the electrolyte within the battery shreds between the low-temperature stabilization step and the high-temperature stabilization step.

[0139] The intermediate stabilization treatment step may be performed at a temperature higher than the low-temperature stabilization treatment step and lower than the high-temperature stabilization treatment step. In one embodiment, the intermediate stabilization treatment step may be performed at a temperature of 30 to 120°C.

[0140] In one embodiment, the intermediate stabilization treatment step may be performed as a multi-stage heat treatment. The intermediate stabilization treatment step may be performed sequentially at a first temperature of 30 to 60 °C, a second temperature of 60 to 90 °C, and a third temperature of 90 to 120 °C.

[0141] In this way, by performing an intermediate stabilization treatment step prior to a high-temperature stabilization treatment step, the temperature of the battery shreds can be gradually increased to stably volatilize the electrolyte within the battery shreds.

[0142]

[0143] Hereinafter, preferred embodiments and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

[0144] <Experimental Example>

[0145] <Battery internal temperature according to minimum freezing time>

[0146] Figure 1 shows the change in voltage of a battery according to cooling temperature according to one embodiment of the present invention.

[0147] Referring to Fig. 1, when the battery voltage is measured while freezing the battery to -80°C, the battery pack shows almost the same voltage at a high temperature of about 40°C, room temperature, and up to -60°C, confirming that the battery characteristics are not lost. Next, when the temperature decreases from -60°C to -70°C, the voltage drops rapidly, and below -70°C, the voltage becomes 0 V. In this way, it was confirmed that a short circuit does not occur when the battery is frozen to -60 to -150°C.

[0148] FIG. 2 is a graph showing the relationship between battery weight, external cooling temperature, and cooling time according to one embodiment of the present invention.

[0149] Referring to FIG. 2, it can be confirmed that a battery processing method according to an embodiment of the present invention can derive a minimum cooling time for cooling a battery in the step of freezing a battery. Specifically, it can be confirmed that the minimum cooling time is related to the battery weight, the external cooling temperature, and the target temperature. Specifically, when the target temperature is set to -70°C and the battery weights are 2.5 kg (A), 10 kg (B), 20 kg (C), and 50 kg (D), the external cooling temperature and the minimum cooling time are shown. When cooling the battery, it can be confirmed that the electrolyte of the battery begins to cool after a predetermined period of time and the voltage becomes 0 V. Through this, it can be confirmed that a minimum maintenance time is required to sufficiently cool the inside, specifically the electrolyte, when cooling the battery.

[0150] Specifically, in a heat transfer situation for cooling where heat is lost to the outside, considering the specific heat of the battery itself, it can be confirmed that the battery weight and cooling time are required. Thus, the present invention can determine the minimum time required for cooling by using the external cooling temperature for refrigeration, the target temperature, and the battery weight.

[0151] Table 1 below lists the minimum cooling time based on battery weight and external cooling temperature.

[0152] Battery weight [kg] External cooling temperature [℃] Target temperature [℃] Formula 1 Minimum cooling Time[h]A_12.5-120-701.91.9A_22.5-100-702.92.9A_32.5-80-704.44.4B_110-120-703.13.1B_210-100-704.64.6B_310-80-707.0 7.0C_120-120-703.93.9C_220-100-705.85.8C_320-80-708.88.8D_150-120-705.35.3D_250-100-707.97.9D_350-80-7011.911.9

[0153] Looking at Table 1 above, it can be seen that the smaller the battery weight, the shorter the minimum cooling time required for the battery to be cooled. Furthermore, when cooling is performed with the minimum cooling time corresponding to the value of Equation 1 derived from the relationship between the battery weight, external cooling temperature, and target temperature, it can be confirmed that the battery, specifically the electrolyte of the battery, is cooled. Furthermore, when the battery is cooled for a time longer than the value of Equation 1, no fire occurs during the subsequent process of crushing the battery.

[0154] Figures 3a and 3b are photographs of an example according to the minimum cooling time of the present invention, and Figures 3c and 3d are photographs of a comparative example according to the minimum cooling time of the present invention.

[0155] Referring to Figures 3a and 3b, the fire occurrence status of shredded material was tested when the battery was frozen for a time shorter than the minimum cooling time required for cooling. In the experiment, when the battery weight was 25 kg, the external cooling temperature was -95°C, and the target freezing temperature was -70°C, the experiment was conducted for 5 hours, which is lower than the value of Equation 1, when the value of Equation 1 below was 7 hours.

[0156] <Formula 1>

[0157] Minimum cooling time = A × (W 0.33 )

[0158] (A = 4 × e(-0.02×dT), W = battery weight (Kg), dT= │external cooling temperature - target temperature│, ││ represents the absolute value)

[0159] Referring to Figures 3c and 3d, the fire occurrence status of shredded material was tested when the battery was frozen for a period exceeding the minimum freezing time required for cooling. The above experiment was conducted under the same battery weight as Figures 3a and 3b, the external cooling temperature, and the minimum freezing time of 7 hours or more.

[0160] Table 2 below compares the fire occurrence status of the examples and comparative examples according to the same battery weight, external cooling temperature, and minimum freezing time according to 3a to 3d. The fire occurrence status was determined as "O" if fire occurrence was observed after crushing the battery, and "X" if not.

[0161] Battery weight [Kg] External cooling temperature [℃] Target temperature [℃] Formula 1 Actual cooling time [h] Fire occurrence Comparative example 25- 95- 707.05 O Example 25- 95- 707.07 X

[0162] Looking at Table 2 above, it can be seen that if the battery is cooled to a value lower than the value in Equation 1, which corresponds to the minimum cooling time, the electrolyte is not cooled, resulting in a fire after the battery is shredded. Thus, it can be confirmed that if the battery is cooled using the value in Equation 1 as the minimum cooling time, the shredded material can be reliably utilized without a fire after the battery is shredded.

[0163]

[0164] <Battery Shredding Stage - Shredder Size>

[0165] Even if a frozen battery is shredded, the likelihood of a fire occurring during shredding is low. However, a potential difference will develop within the shredded material depending on the battery's state of charge. In the present invention, a standard for stabilizing the shredded material was established by measuring the temperature rise of the shredded material.

[0166]

[0167] Figure 4 is a graph of temperature over time of a shredded material according to one embodiment of the present invention.

[0168] Figure 4 shows the temperature change over time for 20 mm-sized shredded materials to determine the maximum ignition temperature. Specifically, after shredding a battery that had undergone a freezing step, the resulting shredded materials, 20 mm in size, were exposed to the air and subjected to air cooling to measure the temperature change over time. For 20 mm-sized shredded materials, the maximum ignition temperature was confirmed to be approximately 65°C. This is lower than the average evaporation temperature of the electrolyte, 120°C.

[0169] Table 3 below shows the temperature increase amount measured according to the size of the shredded material.

[0170] Average shredded material size (mm) 110 20 50 100 150 Heating amount [℃] 30 50 65 90 110 140

[0171] Looking at Table 3 above, it can be confirmed that there is a difference in the reheating temperature depending on the size of the crushed material, and it was confirmed that the average size of the crushed material should be crushed to within 100 mm in the long axis, which is the longest axis among the horizontal, vertical, and height directions, as the stabilization temperature for process design.

[0172] Additionally, depending on the size of the shredded material, the shredded material requires time to physically stabilize. Stabilizing the shredded material involves maintaining the material at a temperature lower than 120°C for a predetermined process time, or maintaining the material for a predetermined process time while in an inert gas atmosphere to reduce contact with atmospheric oxygen.

[0173] In the present invention, the crushed material was maintained at a room temperature of 30°C for approximately 3 hours based on an average crushed material size of 20 mm, and at this time, it was confirmed that the increased temperature of the crushed material had dropped to the room temperature level.

[0174] For the above stabilization time, for fragments less than 100 mm, there is no problem if the holding time is within a few minutes, but for fragments greater than 100 mm, the stabilization time must be at least 3 hours.

[0175]

[0176] <Battery shredding stage - Shredder layer control stage of battery shredder>

[0177] When crushing is performed below the minimum freezing time of the crushed material, the crushed material does not undergo brittle fracture in an ultra-low temperature state, and thus the size of the crushed material increases, or the thickness of the crushed material increases due to the existence of multiple layers of positive and negative current collectors. As the layer thickness of the crushed material increases, there are problems in that the temperature rises significantly and the heating time takes a long time.

[0178] Table 4 below shows the temperature rise according to the layered structure in a unit battery shredder according to one embodiment of the present invention, measured using a thermal imaging camera.

[0179] Referring to Table 4 below, in the case of a layered structure, anode-separator-cathode means 1 layer, and when the shredded material is laminated in multiple layers, it is arranged in the order of anode-separator-cathode-separator-anode-separator-cathode... Specifically, it means that the separator structure is arranged in multiple layers between the anode or the cathode in the waste battery as a 1-layer structure. Specifically, the anode or cathode may be arranged on at least one side of the separator based on the separator.

[0180] In Table 4 below, the average size of the shredded material was evaluated as 20 mm, and the temperature of each layer of the shredded material after shredding was evaluated and the recovery time required to rise from the freezing temperature to the maximum temperature and then drop back down to 40°C was measured.

[0181] At this time, the size of the shredded material was measured based on the long axis among the long and short axes of the shredded material.

[0182] Layered structure Number of layers [Number of layers] Size of crushed material [mm] Maximum temperature [℃] Below 40 ℃ Recovery time [min] Note Experimental example 2 206 3 1 1 0 Example Experimental example 3 206 4 1 1 0 Example Experimental example 5 207 5 1 4 4 Example Experimental example 7 201 0 5 2 0 0 Example Experimental example 10 1 0 Combustion-comparative example

[0183] FIGS. 5A to 5C illustrate unit battery fragments according to one embodiment and a comparative example of the present invention.

[0184] Referring to FIG. 5a, examples and comparative examples can be confirmed according to the shredder size and the number of layers of the layered structure of the unit battery shredder.

[0185] When examining the above FIG. 5a and Table 4 simultaneously, it was confirmed that when the number of layers of the layered structure was 3 or less, the temperature of the crushed material was stably maintained at 110°C or less, and when the number of layers was higher than 7, the temperature rose to a temperature higher than 105°C and combustion occurred because it reacted with the electrolyte.

[0186] Referring to Fig. 5b, the mixing ratio according to the weight ratio of the battery shreds can be confirmed. Specifically, the weight of the battery shreds with a layered structure of 7 layers or less (left side of Fig. 5b) was mixed at 905 g, and the weight of the battery shreds with a layered structure of more than 7 layers (right side of Fig. 5b) was mixed at 95 g.

[0187] It was confirmed that, for the battery shredders, if the size exceeds 100 mm for one layer, the maximum temperature rises to over 105°C, which increases the possibility of fire. In addition, it was confirmed that, even if the size is less than 100 mm, the possibility of fire increases when the number of layers in the layered structure is 10 or more, specifically, more than 7.

[0188] Table 5 below shows the possibility of fire occurrence according to the weight % ratio of the battery shredder of the present invention having a layered structure exceeding 7 layers.

[0189] 7th floor Excess weight ratio [%] Number of experiments [number of times] Frequency of fire occurrence [number of times] Fire occurrence Remarks Experimental example 2 Less than 100X - Experimental example 2 - 5100X - Experimental example 6 - 10101△ Smoke occurrence Experimental example 10 Exceeds 33O Fire occurrence

[0190] Looking at Table 5 above, as a result of measuring the frequency of fire occurrence within the shredded material in units of 1 kg cells, it was confirmed that even when the weight ratio of shredded material with a layered structure exceeding 7 layers was included, if it was included at 10% or less based on the total weight ratio, fire occurrence was almost non-existent. In addition, when the weight ratio of shredded material with a layered structure exceeding 7 layers was included at 10% or more based on the total weight ratio, fire occurrence was confirmed in all three experiments. At this time, it was confirmed that the ignition location of the fire started in the shredded material that was thicker than 7 layers.

[0191] In this way, it was confirmed that when the weight ratio of shredded material having a layered structure of more than 7 layers is 10% or less, specifically 5% or less, of the total weight of the shredded material, fire in the shredded material can be prevented, and it was confirmed that the frequency of fire occurrence increases when the weight ratio of shredded material having a layered structure of more than 7 layers or shredded material having a size greater than 100 mm among the total weight of the battery shredded material exceeds 10%.

[0192] In addition, Table 6 below confirms whether smoke is generated according to the ratio of combustion traces on the surface of the shredded material according to one embodiment of the present invention.

[0193] Combustion area / normal area ratio [%] Smoke generation Remarks Experimental example 10X Example Experimental example 20X Example Experimental example 30X Example Experimental example 30 Exceeded O Comparative example

[0194] FIG. 5c illustrates a combustion section and a top section of a surface of a unit battery shredder according to one embodiment of the present invention.

[0195] Referring to Figure 5c, the surface of the unit battery shredded material can be identified as a normal area without signs of combustion due to high temperature and a surface of the shredded material with signs of combustion due to high temperature. The burned area refers to an area with signs of combustion due to high temperature, and may be specifically a rapidly heated area. It refers to an area with a darker color compared to the normal area, which is an unburned area. The burned area appears to have mostly burned edges.

[0196] Looking at Figure 5c and Table 6 above, when there are almost no traces of combustion due to high temperature on the surface of the unit battery shredder or when the traces of combustion within the surface area are 30% or less, it was confirmed that no combustion occurred when evaluating the presence or absence of smoke generation. When the traces of combustion within the surface area exceeded 30%, it was confirmed that a fire accompanied by smoke occurred.

[0197]

[0198] <Battery Stabilization Stage: Temperature Trends of Shredded Material According to SOC Conditions of Waste Battery>

[0199] Figures 6a to 6c are photographs showing the temperature measurement process of a waste battery and the temperature trend of the shredded material according to the SOC conditions.

[0200] Figures 6a and 6b show the temperature before and after battery shredding, and Figure 6c shows the temperature trend of the shredded material according to the SOC condition of the spent battery. Referring to Figure 6a, in order to measure the temperature before the spent battery was shredded, a hole of about 30 mm was drilled in the center of the battery module, and a TC (Thermal Couple) was installed to measure the temperature. Referring to Figure 6b, in order to measure the temperature of the shredded material after the spent battery was shredded, a TC (Thermal Couple) was installed in the center of the shredded material to measure the temperature.

[0201] Referring to Fig. 6c, the temperature patterns measured at 0% and 30% SoC conditions of the battery are shown. The SoC stands for 'State of Charge' and refers to the state of charge of a lithium-ion battery. Specifically, to indicate the remaining capacity of the battery, the currently usable battery capacity is divided by the total capacity and expressed as a percentage (%). This graph was measured by installing a TC (Thermal Couple) at the center of the shredded material to measure the internal temperature after the battery was cryo-fractured.

[0202] Figure 7 is a graph showing the temperature increase trend of the shredded material according to the SOC % condition of the battery.

[0203] Referring to Fig. 7, it was confirmed that the battery with SoC 0% was shredded in a frozen state, and the initial temperature started at approximately -60℃ and rose to a maximum temperature of approximately 30℃, and the battery with SOC 30% was confirmed to rise to 60℃. Through this, it is necessary to check in advance the SOC status of the shredded material that is to be stabilized at low temperature by self-heating during stabilization. Specifically, it was confirmed that the maximum temperature trend according to the SOC condition was 80% or higher, and a fire occurred during stabilization.

[0204]

[0205] <Battery stabilization stage>

[0206] FIG. 8 is a graph showing the temperature of battery shreds over time in low-temperature stabilization, intermediate stage, and high-temperature stabilization stages according to one embodiment of the present invention.

[0207] Figure 8 is a graph showing the temperature of battery shreds when stabilization treatments were continuously performed for up to 24 hours, including low-temperature stabilization for up to 12 hours, intermediate stabilization for up to 12 hours, and high-temperature stabilization for up to 12 hours. It was confirmed that by performing the low-temperature stabilization process, followed by the intermediate and high-temperature stabilization steps, the battery shreds could be stabilized by preventing a rapid increase in temperature, thereby obtaining a stabilized battery.

[0208] Figure 9a is a schematic diagram of a stabilization device for performing a battery stabilization step, and Figure 9b is a graph showing self-heating of battery shreds inside a transport container.

[0209] Referring to Figure 9a, after the cryo-fracturing of the battery is completed, the shredded material is placed into a stabilization device. Subsequently, the low-temperature stabilization process is performed for up to 12 hours at temperatures of approximately 10 to 20°C, gradually removing the low-temperature electrolyte while transporting.

[0210] Figure 9b illustrates the temperature change in a transport container containing shredded battery waste with an SOC of 30% or less. Specifically, the ambient temperature in Figure 9b refers to the temperature of the transport container. During the low-temperature stabilization stage, the temperature inside the transport container increases due to the self-heating of the battery shredded battery waste during transport. At this time, it is desirable to control the temperature of the battery shredded battery waste to 30°C or lower during the low-temperature stabilization stage.

[0211] Figure 10 shows the temperature change of the crushed material when the heating temperature was controlled for each section for heat treatment in the high-temperature stabilization stage.

[0212] Referring to Figure 10, the crushed material that has undergone the low-temperature stabilization step undergoes a high-temperature stabilization treatment step. In the high-temperature reduction treatment step, the temperature is controlled by adjusting the power (%) of the heating device for each section (6 sections) for continuous heat treatment, thereby increasing the temperature of the crushed material, and thereby removing the electrolyte within the crushed material.

[0213]

[0214] <Temperature heating pattern of stabilized shredded material>

[0215] Figure 11 shows the weight reduction ratio (%) of the electrolyte in the shredded battery according to the heat treatment temperature of 150°C after high-temperature stabilization treatment of the shredded battery.

[0216] Referring to Fig. 11, when performing high-temperature stabilization treatment on a battery, the heat treatment temperature of the shredded material is changed, and the weight reduction ratio (%) of the electrolyte contained in the entire shredded material is shown to some extent depending on the temperature conditions. Specifically, when the battery shredded material subjected to high-temperature stabilization treatment was heated to 150°C, it was confirmed that the amount of electrolyte contained in the battery shredded material was reduced to approximately 65 wt% after the high-temperature stabilization treatment, when the total amount of electrolyte contained in the battery shredded material was 100 wt%. The battery shredded material subjected to the high-temperature stabilization treatment is a stabilized lithium-ion shredded material that can be safely processed for battery processing in subsequent processes such as primary sorting or dry high-temperature treatment.

[0217] Therefore, as a major characteristic of the crushed material stabilized after cryo-crushing, it was confirmed that the crushed material stabilized at low temperature was additionally stabilized at high temperature, and when the stabilized battery crushed material was heated at 150°C, the change in mass before and after heating was very low.

[0218]

[0219] <Tap density change>

[0220] Figure 12 shows the temperature and weight reduction according to the tap density of the battery shredder.

[0221] Referring to Figure 12, before performing low-temperature stabilization, the tap densities of the crushed battery waste were 250, 350, 450, and 550 kg / m, respectively. 3 When the battery shredder has undergone the battery stabilization step of the present invention, the weight reduction amount is shown. When the tap density of the battery shredder is 550 kg / m 3 at 250 kg / m 3 When sequentially lowered, it was confirmed that a gap was formed within the battery shreds, facilitating the evaporation of the electrolyte and increasing the weight reduction compared to the weight of the electrolyte (100%) inside the battery.

[0222]

[0223] <Evaluation Example>: Data according to low-temperature stabilization and high-temperature stabilization conditions

[0224] Table 7 below shows the weight reduction amount and tap density of the unit battery shredder having a layered structure of seven layers and having a size of 20 mm based on the long axis, which is the longest axis among the horizontal, vertical, and height directions, when the unit battery shredder is subjected to low-temperature stabilization treatment and high-temperature stabilization treatment step conditions described in Table 7 below.

[0225] At this time, a multi-stage intermediate stabilization treatment step was performed between the low-temperature stabilization treatment step and the high-temperature stabilization treatment step, and the intermediate stabilization treatment steps were heat-treated continuously in the temperature ranges of 30 to 60, 60 to 90, and 90 to 120 ℃, respectively, and the high-temperature heat treatment time mentioned above was performed for 12 h including the intermediate stabilization treatment time.

[0226] The weight loss of the crushed material after the low-temperature stabilization treatment step and the high-temperature stabilization treatment step was measured using a weight measuring device.

[0227] Tap density was measured by crushing a commercial battery module (consisting of 30 cells) weighing approximately 30 kg using a crusher, placing it in a stabilized volume case (0.44 m wide × 0.7 m long × 0.5 m high), and mechanically tapping it to obtain the apparent density. Specifically, the density (ρ = M / V) is obtained by dividing the battery weight (M, kg) by the volume of the case (V, m3).

[0228] The weight loss ratio after reheating the shredded material was determined by reheating the unit battery shredded material that had gone through the high-temperature stabilization treatment step to 150 ℃ and then checking the weight loss ratio before and after heating.

[0229] Stability was indicated as × if a fire occurred during the battery crushing process, and ○ if no fire occurred.

[0230] Tap density [kg / m 3 ] Low-temperature stabilization treatment stage conditions Low-temperature stabilization treatment stage Weight reduction of crushed material after the low-temperature stabilization treatment stage [%] High-temperature stabilization treatment stage Weight reduction of crushed material after the high-temperature stabilization treatment stage [%] Weight reduction ratio after reheating of crushed material [%] Stability Temperature [℃] Time [h] Temperature [℃] Time [h] Example 250 10 6 3.7 150 129.5 0.7 ○ Example 250 10 9 3.9 140 129.30.5 ○ Example 250 20 124.11 30 68.5 0.9 ○ Example 250 25 124.4 150 129.6 1.0 ○ Comparative example 250 0242.5 100 56.43.1 × Comparative example 250 40 33.1 200 57.3 2.2 ×

[0231] Referring to Table 7 above, the low-temperature stabilization treatment of the example was performed in the range of 10 to 25°C for 6 to 12 hours, and the high-temperature stabilization treatment was performed in the range of 130 to 150°C for 6 to 12 hours. At this time, when examining the weight loss after reheating the shredded material, it can be confirmed that it is 1.0% or less, and since the weight loss after reheating the shredded material satisfies 1.0% or less, it was confirmed that the electrolyte reduction amount was large and stability in the post-process was secured. In contrast, when the low-temperature stabilization treatment process was not performed or was performed at a high temperature such as 40°C, there was a problem that there was a risk of fire in the battery, and it was confirmed that the weight loss of the obtained battery shredded material was low. In addition, when the low-temperature stabilization treatment was not sufficiently performed and the high-temperature stabilization treatment was performed, there was a problem that low-temperature volatile electrolyte was excessively generated during the high-temperature treatment, which further increased the risk of fire, and there was a problem that the electrolyte reduction was not sufficiently achieved compared to the standard time.

[0232] 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

1. As a unit battery shredder for recovering valuable metals from waste batteries, The above unit battery shredder is a unit battery shredder having a layered structure including a separator having a positive electrode or a negative electrode laminated on at least one surface, and satisfying the following conditions 1, 2, and 3. <Condition 1> The above layered structure is a laminated structure having 1 or more layers and 7 or fewer layers. <Condition 2> The size of the unit battery shreds based on the longest axis among the horizontal, vertical, and height directions is 100 mm or less. <Condition 3> When the above unit battery shreds are reheated at 150°C, the weight of the above unit battery shreds decreases by 1.0% or less.

2. In paragraph 1, The surface of the above unit battery shreds is a combustion zone, which is an area where at least a portion of the surface is burned, and Including a top portion with no traces of combustion on the surface, Unit battery shreds having an area ratio of the combustion zone to the above-mentioned normal zone of 30% or less.

3. In paragraph 2, The above combustion unit is a unit battery shredder formed at the edge of the surface.

4. As a unit battery shredder for recovering valuable metals from waste batteries, A battery shredder comprising at least one unit battery shredder having a layered structure including a separator having a positive electrode or a negative electrode laminated on at least one surface, and satisfying the following conditions 1, 2, and 3. <Condition 1> The above layered structure is a laminated structure having 1 or more layers and 7 or fewer layers. <Condition 2> The size of the unit battery shreds based on the longest axis among the horizontal, vertical, and height directions is 100 mm or less. <Condition 3> When the above unit battery shreds are reheated at 150°C, the weight of the above unit battery shreds decreases by 1.0% or less.

5. In paragraph 4, The content of the above unit battery shreds is 90% or more of the total volume of the above battery shreds.

6. In paragraph 4, Battery scrap containing impurities in weight %, Na: 0.4 % or less, Ca: 0.03 % or less, Mg: 0.02 % or less, and K: 0.02 % or less.

7. Step for freezing the battery; A step of crushing the frozen battery into battery shredders; and Comprising a step of stabilizing the shredded battery waste, The above battery shreds comprise at least one unit battery shred, The above unit battery shredder has a layered structure including a separator with a positive or negative electrode laminated on at least one side, and satisfies the following conditions 1 and 2: The above stabilizing step is a battery processing method that satisfies the following condition 5. <Condition 1> The above layered structure is a laminated structure having 1 or more layers and 7 or fewer layers. <Condition 2> The size of the unit battery shreds based on the longest axis among the length, width, and height directions is 100 mm or less. <Condition 5> Low-temperature stabilization treatment is performed at 30°C or lower, and after the low-temperature stabilization treatment, high-temperature stabilization treatment is performed at 30°C or higher to 150°C.

8. In paragraph 7, A battery processing method, wherein the weight of the battery shreds in the low-temperature stabilization treatment step is reduced by 2.8 to 4.6% compared to the weight of the battery shreds before performing the low-temperature stabilization treatment step.

9. In paragraph 7, A battery processing method, wherein the weight of the battery shreds in the high-temperature stabilization treatment step is reduced by 8 to 10% compared to the weight of the battery shreds before performing the low-temperature stabilization treatment step.

10. In paragraph 7, The above battery shredder is a battery processing method that satisfies the following condition 4. <Condition 4> The tap density of the above battery shreds is 200 to 600 kg / m 3 am 11. In paragraph 7, A battery treatment method wherein the low-temperature stabilization time in the above low-temperature stabilization treatment is 6 to 12 hours.

12. In paragraph 7, A battery treatment method wherein the high temperature stabilization time in the above high temperature stabilization treatment is 5 to 12 hours.

13. In paragraph 7, A battery processing method performed at a temperature of 0 to 150°C applied to the shredded material for stabilization treatment.

14. In paragraph 7, A battery processing method including an intermediate stabilization processing step prior to the above high temperature stabilization processing step, A battery processing method wherein the intermediate stabilization treatment step is performed at a temperature of 30 to 120° C.

15. In paragraph 14, The above intermediate stabilization treatment step is performed by multi-stage heat treatment, A battery processing method in which the above multi-stage heat treatment is sequentially performed at a first temperature of 30 to 60°C, a second temperature of 60 to 90°C, and a third temperature of 90 to 120°C.

16. In paragraph 7, A battery processing method wherein the shredding step includes a step of controlling the proportion of the unit battery shreds to be 90% or more within the total volume of the battery shreds.

17. In paragraph 7, A battery processing method in which the freezing step is performed by cooling to -150°C to -20°C.

18. In paragraph 7, The above freezing step is performed by cooling to -60℃ to -20℃, A battery processing method in which the above crushing step is performed under vacuum conditions of 100 torr or less.

Images