Processing method of battery member

Abstract

To provide a processing method for a battery member which achieves both enhancement in the collection rate of a carbon component and reduction in the loss rate of the metal component.SOLUTION: A processing method disclosed herein includes: a heating step S10 of heating, at 850°C or higher, a collection object including a positive electrode including at least a lithium-transition metal complex oxide having a layered structure and a negative electrode including a carbon material; and a separation step S30 of adding a foaming agent and a scavenger to a slurry including the collection target after the heating step S10 and separating a metal component and a carbon component included in the collection target.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed herein relates to a method for treating battery components. [Background technology]

[0002] Lithium ion secondary batteries are widely used in various fields. Various materials including metal components such as Ni, Co, and Mn and carbon components such as graphite are used in these lithium ion secondary batteries. For example, lithium transition metal composite oxides such as lithium nickel composite oxide, lithium cobalt composite oxide, and lithium nickel cobalt manganese composite oxide are used as the positive electrode active material. Aluminum foil or the like is used for the positive electrode core. On the other hand, carbon materials or the like are used for the negative electrode active material. Copper foil or the like is used for the negative electrode core. In recent years, recovery techniques have been considered for recovering metal components and carbon components from used batteries and process scraps and reusing them as battery materials. For example, Non-Patent Document 1 discloses that a slurry containing the object to be recovered is filtered and then fired at 500 ° C., and then flotation is performed to separate the positive electrode active material and graphite. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Ruiting Zhan, Zachary Oldenburg, Lei Pan,Recovery of active cathode materials from lithium-ion batteries usingfroth flotation,Sustainable Materials and Technologies 17,September 2018 Summary of the Invention [Problem to be solved by the invention]

[0004] Non-Patent Document 1 describes that when the graphite recovery rate is 98% or more, the loss rate of the positive electrode active material is 8%. In recent years, for example, in Europe, there has been a movement to set a high resource recycling rate (95% or more), and there is a demand for both an improvement in the recovery rate of the carbon component and a reduction in the loss rate of the metal component contained in the positive electrode active material. In particular, it is preferable that the loss rate of the metal component is 5% or less.

[0005] The present invention has been made in consideration of the above circumstances, and its main object is to provide a method for treating battery components which achieves both an improvement in the recovery rate of carbon components and a reduction in the loss rate of metal components. [Means for solving the problem]

[0006] The method for treating battery components disclosed herein includes a heating step of heating a recovery object including a positive electrode including at least a lithium transition metal composite oxide having a layered structure and a negative electrode including a carbon material at 850°C or higher, and a separation step of adding a foaming agent and a collector to a slurry including the recovery object after the heating step to separate metal components and carbon components contained in the recovery object.

[0007] In the treatment method having the above configuration, the metal components in the target are reduced to elemental metal state by heating the target to 850°C or higher. The elemental metal aggregates, and the specific gravity can be favorably increased. This improves the sedimentation property of the metal components and improves the separability from the carbon components. Therefore, the metal components and the carbon components can be favorably separated in the separation process, and the recovery rate of the carbon components is improved and the loss rate of the metal components is favorably realized. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a vertical cross-sectional view that illustrates a schematic internal structure of a lithium-ion secondary battery. [Diagram 2] FIG. 2 is a perspective view that typically shows an electrode assembly of the lithium ion secondary battery shown in FIG. [Diagram 3]FIG. 3 is a flowchart illustrating a method for treating battery components according to one embodiment. [Figure 4] FIG. 4 is a flow chart illustrating in detail the heating step in the manufacturing method according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. Note that matters other than those specifically mentioned in this specification and necessary for implementing the technology disclosed herein can be understood as design matters for a person skilled in the art based on the prior art in the field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the field.

[0010] 1. Items to be recalled The method for treating battery components disclosed herein is a method for separating and recovering metal components such as Ni, Co, Mn, and carbon components such as graphite from a predetermined collection target. The recovered metal components and carbon components can be suitably used as materials for the positive electrode active material and / or negative electrode active material of a lithium ion secondary battery. An example of the collection target here is a used lithium ion secondary battery. This lithium ion secondary battery will be specifically described below. FIG. 1 is a vertical cross-sectional view that typically shows the internal structure of a lithium ion secondary battery. FIG. 2 is a perspective view that typically shows an electrode body of the lithium ion secondary battery shown in FIG. 1.

[0011] As shown in FIG. 1, the lithium ion secondary battery 1 includes a case 10, an electrode assembly 20, and an electrolyte (not shown).

[0012] (1) Case The case 10 is a box-shaped container. An electrode body 20 and an electrolyte are housed inside the case 10. For example, a metal material (such as aluminum (Al)) having a certain strength is used for the case 10. A positive electrode terminal 12 and a negative electrode terminal 14 are attached to the case 10. The positive electrode terminal 12 and the negative electrode terminal 14 are connected to the electrode body 20 inside the case 10. Specifically, the positive electrode terminal 12 is connected to a positive electrode plate 30 (see FIG. 2) of the electrode body 20. The positive electrode terminal 12 is made of aluminum (Al) or the like. On the other hand, the negative electrode terminal 14 is connected to a negative electrode plate 40 (see FIG. 2) of the electrode body 20. The negative electrode terminal 14 is made of copper (Cu) or the like.

[0013] (2) Electrode body The electrode body 20 is a power generating element of the lithium ion secondary battery 1. As shown in Fig. 2, the electrode body 20 includes a positive electrode plate 30, a negative electrode plate 40, and a separator 50. The electrode body 20 shown in Fig. 2 is a wound electrode body. This wound electrode body is produced by stacking the positive electrode plate 30, the negative electrode plate 40, and the separator 50 to form a long strip-shaped laminate, and then winding the laminate. However, the structure of the electrode body 20 is not particularly limited, and may be any other conventionally known structure (such as a laminated electrode body).

[0014] The positive electrode plate 30 includes a positive electrode core 32, which is a metal foil having electrical conductivity, and a positive electrode active material layer 34 applied to the surface of the positive electrode core 32. The positive electrode core 32 is made of a metal foil (for example, aluminum foil). The positive electrode active material layer 34 is a composite layer containing a positive electrode active material, a conductive material, a binder, and the like. The positive electrode active material is preferably a lithium transition metal composite oxide having a layered structure. Examples of the lithium transition metal composite oxide having such a layered structure include lithium nickel composite oxide, lithium cobalt composite oxide, and lithium nickel manganese cobalt composite oxide. According to the manufacturing method of this embodiment, metal components (valuable metals) such as Ni, Co, and Mn can be efficiently recovered from a recovery target containing such a lithium transition metal composite oxide having a layered structure. Examples of the conductive material contained in the positive electrode active material layer 34 include carbon materials such as acetylene black and graphite. Moreover, examples of the binder contained in the positive electrode active material layer 34 include resin materials such as polyvinylidene fluoride (PVdF).

[0015] The negative electrode plate 40 includes a negative electrode core 42, which is a metal foil having electrical conductivity, and a negative electrode active material layer 44 applied to the surface of the negative electrode core 42. The negative electrode core 42 is made of a metal foil (e.g., copper foil). The negative electrode active material layer 44 is a composite layer containing a negative electrode active material, a binder, a thickener, and the like. The negative electrode active material contains a carbon material. Examples of the carbon material include graphite, hard carbon, and soft carbon. Examples of the negative electrode active material include silicon (Si), a composite containing carbon and silicon (SiC), silicon oxide (SiO X ) and the like. Among them, it is preferable that the negative electrode active material contains graphite. Examples of the binder contained in the negative electrode active material layer include resin materials such as styrene butadiene rubber (SBR). Examples of the thickener contained in the negative electrode active material layer include resin materials such as carboxymethyl cellulose (CMC).

[0016] The separator 50 is an insulating sheet interposed between the positive electrode plate 30 and the negative electrode plate 40. For example, a resin material such as polyethylene (PE), polypropylene (PP), polyester, cellulose, or polyamide is used for the separator 50. A heat-resistant layer containing an inorganic filler may be formed on the surface of the separator 50. Examples of such inorganic fillers include inorganic oxides such as aluminum oxide, magnesium oxide, silicon oxide, and titanium oxide; nitrides such as aluminum nitride and silicon nitride; metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide; and clay minerals such as mica, talc, boehmite, zeolite, apatite, and kaolin.

[0017] (3) Electrolyte The electrolyte is present between the positive electrode plate 30 and the negative electrode plate 40. This allows charge carriers (Li ions) to move between the positive electrode plate 30 and the negative electrode plate 40. Examples of the electrolyte include a non-aqueous electrolyte solution and a gel electrolyte. Note that the electrolyte may be any electrolyte that can be used in a lithium ion secondary battery without any particular limitation, and does not limit the technology disclosed herein.

[0018] The lithium ion secondary battery 1 has been described above as an example of the object to be collected in the manufacturing method according to the present embodiment. However, the processing method disclosed herein is not limited to the method of collecting the lithium ion secondary battery 1 having the above configuration. For example, at the manufacturing site of the lithium ion secondary battery, some defect may occur in the electrode body after production, and it may become impossible to use it in the product. Such an electrode body may be a collection object because it contains metal components (valuable metals) such as Ni and Co derived from the positive electrode active material and carbon materials such as graphite derived from the negative electrode active material. Alternatively, the electrode body taken out by disassembling a used secondary battery may also be a collection object because it contains metal components such as Ni and Co derived from the positive electrode active material and carbon materials such as graphite derived from the negative electrode active material. In other words, the collection object of the processing method disclosed herein may include at least a lithium transition metal composite oxide having a layered structure and a carbon material, and is not particularly limited to a specific structure.

[0019] 2. Battery component disposal method The treatment method for battery components disclosed herein will be described below. FIG. 3 is a flow chart for explaining the treatment method disclosed herein. FIG. 4 is a flow chart for explaining the heating step in FIG. 3 in detail. The treatment method for battery components disclosed herein includes at least a heating step S10 and a separation step S30. In the separation step S30, which will be described in detail later, the metal component and the carbon component are physically separated and recovered by utilizing the hydrophilicity of the metal component and the hydrophobicity of the carbon component. The treatment method disclosed herein may further include a separation step S20. According to the treatment method disclosed herein, the sedimentation property of the metal component is improved, so that the separation property between the metal component and the carbon component is improved in the separation step S30. This makes it possible to preferably realize an improvement in the recovery rate of the carbon component and a reduction in the loss rate of the metal component. In this specification, the term "carbon component recovery rate" refers to the amount of carbon recovered in the separation process relative to the amount of carbon in the recovery target supplied to the separation process. The amount of carbon can be calculated, for example, by thermogravimetry-differential thermal analysis (TG-DTA). The term "metal component loss rate" refers to the amount of metal recovered in the separation process relative to the amount of metal in the recovery target supplied to the separation process, and the calculated value is subtracted from 100%. The amount of metal can be calculated, for example, by inductively coupled plasma analysis (ICP).

[0020] (1)Heating process S10 In the heating step S10, the above-mentioned recovery target is heated at 850°C or higher. In the recovery target, the metal components (e.g., Ni, Co, Mn) contained in the positive electrode active material are present in the form of metal ions. In the heating step S10, the recovery target is heated at 850°C or higher, so that the metal components can be suitably reduced to the state of simple metals (metal Ni, metal Co, metal Mn). In addition, by heating at least 850°C or higher, the reduced simple metals can be agglomerated, and the specific gravity of the metal components can be increased, improving sedimentation properties. As a result, in the separation step S30 described below, the separability between the metal components and the carbon components can be suitably improved.

[0021] In the heating step S10, the liquid components (electrolyte, etc.) in the collected object and the coating on the surface of the positive electrode active material can be suitably removed by heating the collected object. In addition, the resin components (binder, separator, etc.) contained in the collected object can be carbonized. When a charged lithium ion secondary battery 1 is the collected object, the function as a battery can be stopped by carrying out the heating step S10. This makes it possible to safely carry out the subsequent steps. Although not particularly limited, the heating step S10 may include a preparation step S11, a measurement step S12, a determination step S13, a reducing component addition step S14, and a firing step S15 as shown in FIG. 4. The following will be specifically described.

[0022] (a) Preparation step S11 In the preparation step S11, a collection target is prepared that includes at least a positive electrode containing a lithium composite oxide having a layered structure and a negative electrode containing a carbon material. As described above, in the technology disclosed herein, the "collection target" is not limited to a completed lithium ion secondary battery, but includes defective parts (such as an electrode body) and an electrode body after dismantling a battery. The details of the collection target have already been described, so a duplicated description will be omitted.

[0023] (b) Measurement step S12 In the measurement step S12, the amounts of oxygen element (O) and reduced components contained in the collection target are measured. In the measurement step S12, a part of the collection target is taken as a measurement sample, and the oxygen element and reduced components of the measurement sample are measured. Furthermore, the measurement step S12 only needs to be performed when the type of collection target is changed, and does not need to be performed for all of the prepared collection targets. This can improve production efficiency.

[0024] In this specification, the "reducing component" is not particularly limited as long as it is a component that can reduce a metal component (e.g., Ni, Co, Mn, etc.) contained in the positive electrode active material in the firing step S15 described later. In the treatment method disclosed herein, carbon element (C) can be preferably used as the reducing component. Carbon can be particularly preferably used as the reducing component from the viewpoint that it is not easily oxidized and is stable until the firing step S15 is started. In addition, the types of objects to be recovered can include various carbon materials (conductive materials, binders, negative electrode active materials, etc.). By using these carbon materials as a supply source of the reducing component, it is possible to contribute to reducing the cost required for recovery.

[0025] The means for measuring the amount of substance of the reduced component (carbon element) in the recovery target is not particularly limited, and any conventionally known measuring means can be used without particular limitation. For example, means for measuring the amount of substance of carbon element include thermogravimetric differential thermal analysis (TG-DTA), SEM-EDS analysis, oxygen flow combustion-non-dispersive infrared analysis, and combustion volume method.

[0026] Next, a method for measuring the amount of substance of the oxygen element in the object to be recovered will be described. First, when the chemical composition of the positive electrode active material in the object to be recovered is known in advance, it is advisable to measure the amount of substance of the metal element in the object to be recovered and calculate the amount of substance of the oxygen element based on the amount of substance of the metal element. This makes it possible to easily measure the amount of substance of the oxygen element in a metal oxide (for example, a lithium transition metal composite oxide having a layered structure). A specific example of such a measurement procedure is as follows. First, a solution is prepared by dissolving a part of the object to be recovered (a measurement sample) in an acid. Next, an inductively coupled plasma analysis (ICP) is performed on this solution. This makes it possible to measure the total amount of substance M of the transition metal elements (Ni, Co, Mn) in the object to be recovered. Then, the chemical composition of the positive electrode active material in the object to be recovered (LiNi x Co y Mn z O δ ) is known, the ratio (x+y+z:δ) of the total amount of substance of the transition metal elements (x+y+z) to the amount of substance of O (δ) can be obtained. In this case, the amount of substance N of the oxygen element can be calculated from the ICP measurement results (total amount of substance M of the metal elements) based on the following formula (1). N = δ M / (x + y + z) (1)

[0027] The means for measuring the amount of substance of the oxygen element in the object to be recovered is not limited to the above means, and any conventionally known measuring means can be used without any particular limitation. For example, the oxygen element in the object to be recovered may be directly measured using SEM-EDS analysis, XRF analysis, etc. By using these methods, the amount of substance of the oxygen element can be measured even if the chemical composition of the positive electrode active material in the object to be recovered is unknown.

[0028] (c) Judgment step S13 In the determination step S13, it is determined whether or not the substance amount ratio of the reducing component to the oxygen element is equal to or greater than a predetermined threshold value. Here, the "threshold value" in this step is set based on the stoichiometric ratio of the oxide of the reducing component. For example, when carbon element is used as the reducing component, the above-mentioned "oxide of the reducing component" is carbon dioxide (CO 2In this case, in order to suitably reduce the metal components contained in the positive electrode active material in the firing step S15 described later, the above threshold value is set to be less than or equal to CO 2 It is preferable to set the ratio of carbon element to oxygen element (1 / 2) or more in the determination step S13. In the determination step S13, it is determined whether the substance ratio of carbon element (reducing component) to oxygen element in the recovery target (hereinafter also referred to as "C / O ratio") is 1 / 2 or more. If the C / O ratio is 1 / 2 or more (YES in S13 in FIG. 4), proceed to the calcination step S15. On the other hand, if the C / O ratio is less than 1 / 2 (NO in S13 in FIG. 4), it is preferable to proceed to the reducing component addition step S14. This makes it possible to more suitably reduce the metal components to their elemental metal state.

[0029] As described above, the threshold value in this step may be set to a value equal to or greater than the stoichiometric ratio of the oxide of the reducing component. For example, when the reducing component is carbon element, the threshold value may be set to 3 / 4 or more (more preferably 1 or more, even more preferably 5 / 4 or more, and particularly preferably 3 / 2 or more). This allows only the recovery target containing a large amount of reducing component (carbon element) to be subjected to the calcination step S15, thereby further promoting the reduction of the metal oxide in the calcination step S15.

[0030] (d) Reducing component addition step S14 The reducing component adding step S14 is a step of adding a reducing component to the recovery target when the determination result of the determination step S13 is less than the threshold value (NO in S13 in FIG. 4). In the processing method disclosed herein, it is preferable to perform the reducing component adding step S14 when the determination result of the determination step S13 is less than the threshold value. For example, it is preferable to add a reducing component (carbon-containing material) to the recovery target whose C / O ratio is determined to be less than 1 / 2 in the determination step S13 so that the C / O ratio becomes equal to or greater than the threshold value (1 / 2 or more). This makes it possible to more suitably reduce the metal components contained in the positive electrode active material to a state of simple metal. Note that examples of the carbon-containing material include carbon materials such as graphite, hard carbon, and soft carbon. For example, a negative electrode plate 40 containing a carbon material such as graphite may be further added. The carbon-containing material may also be a resin material such as polyolefin or polyester. These resin materials are carbonized in the early stage of the baking step S15 to generate carbon elements, and therefore can be used as a source of carbon elements.

[0031] In the reducing component adding step S14, a reducing component may be added in an amount that greatly exceeds the threshold value. For example, when the reducing component is carbon element, a carbon-containing material may be added so that the C / O ratio in the recovery target is 3 / 4 or more (more preferably 1 or more, even more preferably 5 / 4 or more, and particularly preferably 3 / 2 or more). This allows the recovery target containing a large amount of reducing component (carbon element) to be subjected to the firing step S15, thereby further promoting the reduction of metal oxide in the firing step S15.

[0032] (e) Firing process S15 In the firing step S15, the recovery target is fired (heated) at 850°C or higher. This allows at least a part of the metal components (e.g., Ni, Co, Mn, etc.) contained in the positive electrode active material to be reduced to a state of simple metals (e.g., metal Ni, metal Co, metal Mn, etc.). These simple metals can be aggregated to increase the specific gravity. This makes it easier for the metal components derived from the positive electrode active material to settle, and in the separation step S30 described below, the separability between the metal components and the carbon components contained in the negative electrode active material is improved. Therefore, both the improvement of the carbon component recovery rate and the reduction of the loss rate of the metal components are suitably achieved. For example, when the recovery target is fired at 850°C or higher in the firing step S15, a reaction as shown in the following formula (2) may occur. This allows at least a part of the metal components contained in the positive electrode active material to be reduced to a state of simple metals.

[0033] LiNi x Co y Mn z O δ +C 1 / 2δ =Li+xNi+yCo+zMn+1 / 2δ·CO 2 (2)

[0034] The heating temperature in the firing step S15 (more specifically, the temperature in the heating furnace) may be 850°C or higher. As the heating temperature increases, the metal element tends to be generated more easily and the metal element tends to aggregate more easily. As described above, the metal element is generated and further aggregates, increasing the specific gravity and improving the sedimentation property. In order to separate the metal component and the carbon component more efficiently in the separation step S30 described later, it is preferable that most of the metal component is reduced to the state of the metal element and the metal element is suitably aggregated. Therefore, from this viewpoint, the heating temperature is preferably 875°C or higher, and may be 900°C or higher. On the other hand, from the viewpoint of reducing the metal component, the upper limit of the heating temperature is not particularly limited, and may be 1500°C or lower, 1400°C or lower, or 1300°C or lower. In addition, in consideration of reducing the cost required for the firing step S15, the upper limit of the heating temperature is preferably 1200°C or lower, more preferably 1100°C or lower, and particularly preferably 1000°C or lower.

[0035] Although not particularly limited, the calcination step S15 is preferably performed by heating the object to be recovered under an inert atmosphere. This can prevent oxygen element from being supplied to the object to be recovered during heating, and more preferably reduces at least a part of the metal oxide (such as lithium transition metal composite oxide) to a state of simple metal. In addition, it is possible to minimize the emission of carbon components as carbon dioxide, which is a greenhouse gas. Specifically, the calcination step S15 is preferably performed by heating the object to be recovered while circulating an inert gas such as argon or nitrogen. Note that the "inert atmosphere" in this specification refers to a heating atmosphere containing the above-mentioned inert gas as a main component. That is, it is not limited to a completely inert atmosphere in which the content of the inert gas is 100% (the content of the oxygen element is 0%), but also includes a heating atmosphere in which the content of the oxygen element is 5% or less (preferably 3% or less, more preferably 1% or less, even more preferably 0.5% or less, and particularly preferably 0.1% or less).

[0036] The calcination time in the calcination step S15 is not generally specified because it differs depending on the amount of the material to be recovered, etc. The calcination time in the calcination step S15 is, for example, preferably 1 hour to 12 hours, and more preferably 2 hours to 8 hours.

[0037] (2) Sorting process S20 As shown in FIG. 3, in the treatment method disclosed herein, it is preferable to carry out the sorting step S20 after carrying out the heating step S10. In the sorting step S20, metal foils such as the positive electrode core 32 and the negative electrode core 42 contained in the collection target after the heating step S10 are physically removed and sorted. In the sorting step S20, for example, the positive electrode core 32 and the negative electrode core 42 are sorted from the collection target after firing using a sieve and removed from the collection target. Since the positive electrode core 32 and the negative electrode core 42 can be composed of metal foil as described above, they have a low specific gravity and tend to float together with graphite in the separation step S30 described later. For this reason, the sorting step S20 is carried out before the separation step S30 to reduce the content of metal foil in the collection target, so that graphite can be more suitably collected in the separation step S30. It should be noted that the sorting step S20 is not a step intended to completely remove the metal foils of the positive electrode cores 32, the negative electrode cores 42, and the like from the objects to be recovered.

[0038] (3) Separation process S30 In the separation step S30, the metal components and the carbon components in the target are separated and recovered. In the separation step S30, a method of flotation of a slurry obtained by adding water to the target after the heating step S10 or the target after the sorting step S20 is preferably used. Flotation (floatation) is a physical sorting method in which hydrophobic components are made to float by adhering them to air bubbles, while hydrophilic components are made to settle. In the flotation, the hydrophobic components and the hydrophilic components can be efficiently separated. In the treatment method disclosed herein, the metal components are hydrophilic components, and the carbon components are hydrophobic components. Therefore, by performing flotation on the slurry containing the target, the carbon components (particularly graphite) of the hydrophobic components can be made to float, and the metal components (valuable metals) of the hydrophilic components can be made to settle, and each can be recovered in a separated state.

[0039] In the separation step S30 using flotation, first, water is added to the object to be recovered after the heating step S10 or the object to be recovered after the sorting step S20 to prepare a slurry containing the object to be recovered. Next, a foaming agent and a collector are added to the slurry and stirred. Then, by stirring the slurry while introducing air, the hydrophobic carbon component is attached to the air bubbles and floated to be recovered. Meanwhile, the remaining slurry contains metal components derived from the positive electrode active material, so the slurry is recovered. This allows the carbon component and the metal component to be suitably separated and recovered separately.

[0040] When separating and recovering the metal components derived from the positive electrode active material and the carbon components derived from the negative electrode active material by flotation, the positive electrode active material is generally fired at a temperature of about 500°C in order to remove the coating and binder on the surface of the positive electrode active material and to increase its hydrophobicity. However, according to the study by the present inventors, the particle diameter of the positive electrode active material is about 10 μm to 20 μm, and the true density is 4.5 g / cm 3 Since the specific gravity of the positive electrode active material is about 8.9 g / cm, it is more likely to settle than carbon materials (especially graphite), but it may float up together with the carbon materials. In contrast, in the treatment method disclosed herein, the metal components contained in the positive electrode active material are reduced to a simple metal state (metallized) by heating (sintering) at 850°C or higher, and the specific gravity is reduced to 8.9 g / cm. 3 The weight of each metal particle can be increased to about 100% by agglomerating the metalized metal components. The weight of each metal particle can be increased by agglomerating the metalized metal components, thereby improving the sedimentation rate compared to the conventional method. This makes it possible to suppress the metal components from floating up together with the carbon components during the separation step S30, thereby reducing the loss rate of the metal components (loss rate of the positive electrode active material). Furthermore, the improved separability allows the process to be carried out under conditions that allow the carbon components to be recovered as much as possible, thereby improving the recovery rate of the carbon components. Therefore, according to the treatment method disclosed herein, it is possible to preferably achieve both a reduction in the loss rate of the metal components and an improvement in the recovery rate of the carbon components.

[0041] The types of foaming agent and collector used during flotation are not particularly limited. The foaming agent dissolves in a solvent to generate foam and has the function of stabilizing the generated foam. Examples of foaming agents include 4-methyl-2-pentanol (MIBC), pine oil, and turpentine oil. The amount of foaming agent is not particularly limited, but is preferably 50 to 200 g / t, more preferably 100 to 150 g / t, relative to 1 ton (t) of the object to be recovered. The collector has the function of selectively adsorbing to the surface of the carbon material and increasing the hydrophobicity of the surface. Examples of collectors include kerosene and heavy oil. The amount of collector is not particularly limited, but is preferably 50 to 200 g / t, more preferably 100 to 150 g / t, relative to 1 ton (t) of the object to be recovered.

[0042] The carbon material recovered in the separation step S30 can be suitably used as a battery material (negative electrode material) by appropriately drying the carbon material recovered in the separation step S30. The metal components recovered in the separation step S30 can be separated into individual metals by appropriately carrying out conventional steps such as an acid leaching step, a neutralization precipitation step, and a solvent extraction step, and can be suitably used as a battery material (positive electrode material).

[0043] The above describes the method for treating battery components according to the present embodiment. As described above, in the method disclosed herein, the recovery target is calcined at 850° C. or higher, thereby improving the separability of the metal components contained in the positive electrode active material and the carbon components contained in the negative electrode active material, and each of them can be recovered appropriately. Note that the technology disclosed herein is not limited to the above-mentioned embodiment, and includes other embodiments in which various configurations are changed.

[0044] [Test example] Test examples relating to the technology disclosed herein will be described below. Note that the contents of the test examples described below are not intended to limit the technology disclosed herein.

[0045] 1. Preparation of test samples (Example 1) In this test, a mixture of positive and negative electrode plates was targeted for recovery, and test samples were prepared according to the following procedure. First, a secondary battery to be recovered was prepared. The positive electrode plate of the secondary battery was prepared by disposing a positive electrode active material layer on the surface of a positive electrode core (Al foil). The positive electrode active material in the positive electrode active material layer was lithium nickel cobalt manganese composite oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ) The negative electrode plate was prepared by coating the surface of a negative electrode core (Cu foil) with a negative electrode active material layer. The negative electrode active material in the negative electrode active material was graphite. Then, this secondary battery (a mixture of a positive electrode plate and a negative electrode plate) was crushed to prepare a powder sample.

[0046] Next, a part of the powder sample prepared above was taken and dissolved in sulfuric acid. Then, ICP was performed on the solution to measure the total amount of Ni, Co, and Mn, M. The composition of the positive electrode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ), the amount of substance N of the oxygen element was set to twice the total amount of substance M (N=2M). In this test, a thermogravimetric differential thermal analysis (TG-DTA) was performed on a portion of the powder sample. In this thermogravimetric differential thermal analysis, the powder sample was heated in an air atmosphere at 800°C. In this analysis, the heating rate from room temperature (20°C) to 800°C was set to 5°C / min. In this way, the amount of carbon in the powder sample prepared above was measured. The measured amount of substance ratio of oxygen element to carbon element (C / O ratio) was then calculated to be 0.01 to 0.01%, and the amount of carbon in the powder sample prepared above was then calculated to be 0.01 to 0.01%. 2 As a result, in the powder of Example 1, the C / O ratio was 1 / 2 or more.

[0047] Next, the powder sample was heated under an inert atmosphere. Specifically, in Example 1, the powder sample was placed in an electric furnace, and the temperature inside the furnace was raised to 1000°C while supplying Ar gas. The heating rate was set to 5°C / min. Then, heating was performed for 5 hours while maintaining the temperature inside the furnace at 1000°C. After that, the temperature inside the furnace was cooled to 50°C, and the powder sample of Example 1 was collected.

[0048] The collected powder sample was sieved through a sieve with a mesh size of 500 μm to obtain a sample after heating. 25 g of the heated sample was fed to a flotation cell and conditioned (mixed) for 5 minutes at a rotation speed of 700 rpm. Next, 3.1 mL (100 g / t solid content) of kerosene was added as a collector, and the slurry was conditioned for 3 minutes. Next, 3.1 mL (100 g / t solid content) of 4-methyl-2-pentanol (MIBC) was added as a foaming agent, and the slurry was conditioned for 2 minutes. Thereafter, air was supplied at a blowing rate of 2 L / min to perform flotation. The bubbles generated during flotation for 1 minute were collected. The collected bubbles were washed with water to obtain a sample of Example 1.

[0049] (Examples 2 to 6) In Examples 2 to 6, the temperature inside the furnace was changed as shown in Table 1. Other than this, the samples of Examples 2 to 6 were obtained in the same manner as Example 1. Note that, in the powder samples of Examples 2 to 6, the measured substance amount ratio of oxygen element to carbon element (C / O ratio) was also 2 The stoichiometric ratio was greater than or equal to 1 / 2.

[0050] (Example 7) In Example 7, a secondary battery (a mixture of positive and negative plates) similar to that in Example 1 was prepared as a recovery target. The secondary battery was crushed and sieved through a sieve with a mesh size of 500 μm to prepare a powder sample. 25 g of the powder sample was supplied to a flotation cell, and flotation was carried out under the same conditions as in Example 1 to obtain the sample of Example 7. That is, in Example 7, flotation was carried out without heating the powder sample.

[0051] 2.Evaluation Test (1) Calculation of carbon component recovery rate TG-DTA analysis was performed on the flotation sample after flotation in each example, and the recovery rate of the carbon component in each example was calculated. Specifically, the flotation sample after flotation in each example was dried, and the carbon amount was calculated from the weight loss amount by TG-DTA. The carbon amount was divided by the carbon amount in the sample supplied to the flotation cell to calculate the recovery rate of the carbon component in each example. The results are shown in Table 1.

[0052] (2) Calculation of metal component loss rate ICP analysis was performed on the sedimentation sample after flotation in each example, and the loss rate of the metal component in each example was calculated. Specifically, the sedimentation sample after flotation in each example was dried, dissolved in acid, and ICP analysis was performed to calculate the amount of metal derived from the positive electrode active material in the sample. The recovery rate of the metal component in each example was calculated by dividing the amount of metal by the amount of metal derived from the positive electrode active material in the sample supplied to the flotation cell. The loss rate of the metal component in each example was calculated by subtracting the recovery rate of the metal component in each example from 100 (%). The results are shown in Table 1.

[0053] [Table 1]

[0054] As shown in Table 1, in Examples 1 to 3, the recovery rate of the carbon component was 90% or more, and the loss rate of the metal component was 4% or less. This is presumably because, by heating the powder sample at 850°C or more, most of the metal components were reduced to a state of simple metal, and the reduced metal components aggregated, increasing their specific gravity and improving sedimentation. Furthermore, by carrying out the separation process after the heating process, it is presumed that the separability of the metal components and the carbon components was improved, and the loss rate of the metal components could be kept low even with a high recovery rate of the carbon components.

[0055] Although the technology disclosed herein has been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. In other words, the technology disclosed herein includes the embodiments described in the following items 1 to 6.

[0056] <Item 1> A heating step of heating a recovery target including a positive electrode including at least a lithium transition metal composite oxide having a layered structure and a negative electrode including a carbon material at 850° C. or higher; a separation step of adding a foaming agent and a collector to the slurry containing the recovery target after the heating step to separate metal components and carbon components contained in the recovery target; A method for treating a battery component comprising the steps of:

[0057] <Item 2> The positive electrode includes a metal foil as a positive electrode core, and the negative electrode includes a metal foil as a negative electrode core, 2. The method according to item 1, further comprising a sorting step of sorting metal foil contained in the target to be recovered prior to the separation step.

[0058] <Item 3> 3. The method according to item 1 or 2, wherein the lithium transition metal composite oxide having a layered structure contains at least Ni and Co.

[0059] <Item 4> 4. The method according to any one of items 1 to 3, wherein the heating step is carried out in an inert atmosphere.

[0060] <Item 5> 5. The method according to any one of items 1 to 4, wherein the heating step includes a reducing component adding step of adding a reducing component such that an amount of the reducing component relative to an amount of the oxygen element contained in the recovery target is equal to or greater than a threshold based on a stoichiometric ratio of an oxide of the reducing component.

[0061] <Item 6> The reducing component is elemental carbon, and the threshold value is CO2 6. The method according to item 5, wherein the value is equal to or greater than the stoichiometric ratio. [Explanation of symbols]

[0062] 1. Lithium-ion secondary battery 10 Cases 12 Positive terminal 14 Negative terminal 20 Electrode body 30 Positive plate 32 Positive electrode core 34 Cathode active material layer 40 Negative plate 42 Negative electrode core 44 Negative electrode active material layer 50 Separator

Claims

1. A heating step of heating a recovery target including a positive electrode including at least a lithium transition metal composite oxide having a layered structure and a negative electrode including a carbon material at 850° C. or higher; a separation step of adding a foaming agent and a collector to the slurry containing the recovery target after the heating step to separate metal components and carbon components contained in the recovery target; A method for treating a battery component comprising the steps of:

2. The positive electrode includes a metal foil as a positive electrode core, and the negative electrode includes a metal foil as a negative electrode core, The method according to claim 1 , further comprising a sorting step of sorting metal foils contained in the objects to be recovered prior to the separation step.

3. The method according to claim 1 , wherein the lithium transition metal composite oxide having a layered structure contains at least Ni and Co.

4. The method of claim 1 , wherein the heating step is carried out under an inert atmosphere.

5. 2. The treatment method according to claim 1, wherein the heating step includes a reducing component adding step of adding the reducing component so that the amount of substance of the reducing component relative to the amount of substance of the oxygen element contained in the recovery target is equal to or greater than a threshold based on a stoichiometric ratio of an oxide of the reducing component.

6. The reducing component is carbon element, and the threshold value is CO ２ The method of claim 5, wherein the stoichiometric ratio is equal to or greater than the stoichiometric ratio of

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