Method for treating 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 members.

Background Art

[0002] Lithium-ion secondary batteries are widely used in various fields. Various materials including metal components such as Ni, Co, Mn, etc. and carbon components such as graphite are used for 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. Also, aluminum foil or the like is used for the positive electrode core. On the other hand, carbon materials or the like are used as the negative electrode active material. And copper foil or the like is used for the negative electrode core. In recent years, recovery technologies for recovering metal components and carbon components from used batteries and process scrap materials and reusing them as battery materials have been studied. For example, in Non-Patent Document 1, it is disclosed that after filtering a slurry containing the recovery target and then firing at 500°C, froth flotation is performed to separate the positive electrode active material and graphite.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems 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, there has been a movement to set a high resource recycling rate (95% or more) within the European region, and it is required to achieve both an improvement in the recovery rate of the carbon component and a reduction in the loss rate of the metal components contained in the positive electrode active material. In particular, the loss rate of the metal components preferably becomes 5% or less.

[0005] The present invention has been made in view of such circumstances, and its main object is to provide a method for treating battery members that achieves both an improvement in the recovery rate of the carbon component and a reduction in the loss rate of the metal components.

Means for Solving the Problems

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

[0007] In the treatment method having the above configuration, by heating the recovery target at 850°C or higher, the metal components in the recovery target are reduced to the state of metal simple substances. And since the metal simple substances aggregate, the specific gravity can be suitably increased. Thereby, the sedimentation property of the metal components is improved, and the separability from the carbon components is improved. For this reason, the metal components and the carbon components can be suitably separated in the separation step, and an improvement in the recovery rate of the carbon components and a reduction in the loss rate of the metal components are suitably realized.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. It should be noted that matters other than those specifically mentioned in this specification and necessary for the implementation of the technology disclosed herein can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field.

[0010] 1. Objects to be Recovered The method for processing a battery member disclosed herein is a method for separating and recovering metal components such as Ni, Co, Mn, etc. and carbon components such as graphite from a predetermined object to be recovered. The recovered metal components and carbon components can be suitably used, for example, as materials for the positive electrode active material and / or the negative electrode active material of a lithium-ion secondary battery. An example of the object to be recovered here is a used lithium-ion secondary battery. Hereinafter, this lithium-ion secondary battery will be specifically described. FIG. 1 is a longitudinal sectional view schematically showing the internal structure of a lithium-ion secondary battery. FIG. 2 is a perspective view schematically showing the 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 body 20, and an electrolyte (not shown).

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

[0013] (2) Electrode body The electrode body 20 is a power generation 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. Note that the electrode body 20 shown in FIG. 2 is a wound electrode body here. This wound electrode body is produced by laminating the positive electrode plate 30, the negative electrode plate 40, and the separator 50 to form a long strip-shaped laminate and winding the laminate. However, the structure of the electrode body 20 is not particularly limited, and other conventionally known structures (such as a laminated electrode body) may be used.

[0014] The positive electrode plate 30 includes a positive electrode core 32 which is a conductive metal foil, and a positive electrode active material layer 34 provided on the surface of the positive electrode core 32. The positive electrode core 32 is composed of a metal foil (for example, aluminum foil). Further, the positive electrode active material layer 34 is a composite material 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 such a lithium transition metal composite oxide having a layered structure include a lithium nickel composite oxide, a lithium cobalt composite oxide, and a lithium nickel manganese cobalt composite oxide. According to the manufacturing method according to the present embodiment, metal components (valuable metals) such as Ni, Co, Mn, etc. can be efficiently recovered from a recovery target containing such a lithium transition metal composite oxide having a layered structure. Further, examples of the conductive material contained in the positive electrode active material layer 34 include carbon materials such as acetylene black and graphite. Further, 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 conductive metal foil, and a negative electrode active material layer 44 provided on the surface of the negative electrode core 42. The negative electrode core 42 is composed of a metal foil (for example, copper foil). Further, the negative electrode active material layer 44 is a composite material 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. Further, the negative electrode active material may contain silicon (Si), a composite (SiC) containing carbon and silicon, 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] Further, the separator 50 is an insulating sheet interposed between the positive electrode plate 30 and the negative electrode plate 40. For this separator 50, resin materials such as polyethylene (PE), polypropylene (PP), polyester, cellulose, polyamide, etc. are used, for example. Also, 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, titanium oxide, nitrides such as aluminum nitride, silicon nitride, metal hydroxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and clay minerals such as mica, talc, boehmite, zeolite, apatite, kaolin, etc.

[0017] (3) Electrolyte The electrolyte exists between the positive electrode plate 30 and the negative electrode plate 40. Thereby, charge carriers (Li ions) can be moved between the positive electrode plate 30 and the negative electrode plate 40. Examples of the electrolyte include non-aqueous electrolytes, gel electrolytes, etc. Note that the electrolyte can be used without particular limitation as long as it is an electrolyte that can be used in a lithium-ion secondary battery, and does not limit the technology disclosed herein.

[0018] As described above, as an example of the object to be recovered in the manufacturing method according to the present embodiment, the lithium-ion secondary battery 1 has been described. However, the processing method disclosed herein is not limited to only the method of recovering the lithium-ion secondary battery 1 having the above configuration. For example, at the manufacturing site of a lithium-ion secondary battery, some defects may occur in the electrode body after production, making it unusable as a product. Such an electrode body can also be a recovery target 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, a used secondary battery is disassembled, and the removed electrode body can also be a recovery target because it contains metal components such as Ni and Co derived from the positive electrode active material and carbon components such as graphite derived from the negative electrode active material. That is, the object to be recovered by the processing method disclosed herein only needs to contain at least a layered lithium transition metal composite oxide and a carbon material, and is not particularly limited to a specific structure.

[0019] 2. Processing Method of Battery Member The processing method of the battery member disclosed herein will be described below. FIG. 3 is a flowchart for explaining the processing method disclosed herein. FIG. 4 is a flowchart for explaining in detail the heating step in FIG. 3. The processing method of the battery member disclosed herein includes at least a heating step S10 and a separation step S30. In the separation step S30, as will be described in detail later, the metal component and the carbon component are physically separated using the hydrophilicity of the metal component and the hydrophobicity of the carbon component, and each is recovered. The processing method disclosed herein may further include a sorting step S20. According to the processing method disclosed herein, the sedimentation property of the metal component is improved, so that the separability between the metal component and the carbon component in the separation step S30 is improved. Thereby, an improvement in the recovery rate of the carbon component and a reduction in the loss rate of the metal component are preferably realized. In addition, in this specification, the "recovery rate of the carbon component" means the amount of carbon recovered in the separation step with respect to the amount of carbon in the object to be recovered supplied to the separation step. Such an amount of carbon can be calculated, for example, by thermogravimetric differential thermal analysis (TG-DTA). The "loss rate of the metal component" means obtaining the amount of metal recovered in the separation step with respect to the amount of metal in the object to be recovered supplied to the separation step, and subtracting the value from 100%. Such an amount of metal can be calculated, for example, by inductively coupled plasma analysis (ICP).

[0020] (1) Heating Step S10 In the heating step S10, the above-mentioned object to be recovered is heated at 850°C or higher. Among the objects to be recovered, the metal components (for example, Ni, Co, Mn) contained in the positive electrode active material exist in the state of metal ions. In the heating step S10, by heating the object to be recovered at 850°C or higher, the metal components can be preferably reduced to the state of simple metals (metal Ni, metal Co, metal Mn). And by heating at least at 850°C or higher, the reduced simple metals can be aggregated, and the specific gravity of the metal components can be increased, so that the sedimentation property is improved. Thereby, in the separation step S30 described later, the separability between the metal components and the carbon components can be preferably improved.

[0021] In the heating step S10, by heating the above-mentioned object to be recovered, the liquid components (such as electrolytes) in the object to be recovered and the coating film on the surface of the positive electrode active material can be preferably removed. In addition, the resin components (binder, separator, etc.) contained in the object to be recovered can also be carbonized. When the fully charged lithium-ion secondary battery 1 is used as the object to be recovered, the function as a battery can be stopped by performing the heating step S10. Thereby, the subsequent steps can be carried out safely. 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. This will be specifically described below.

[0022] (a) Preparation step S11 In the preparation step S11, an object to be recovered including at least a positive electrode containing a layered lithium composite oxide and a negative electrode containing a carbon material is prepared. As described above, in the technology disclosed herein, the "object to be recovered" is not limited to the completed lithium-ion secondary battery, but includes defective parts (such as electrode bodies) and electrode bodies after battery disassembly. Since the details of the object to be recovered have already been described, duplicate descriptions are omitted.

[0023] (b) Measurement step S12 In the measurement step S12, the amount of substance of oxygen element (O) and reducing components contained in the object to be recovered is measured. In the measurement step S12, a part of the object to be recovered may be sampled as a measurement sample, and the oxygen element and reducing components of the measurement sample may be measured. Further, the measurement step S12 may be performed only when the type of the object to be recovered is changed, and it is not necessary to perform it on all the prepared objects to be recovered. Thereby, the manufacturing efficiency can be improved.

[0024] Note that the "reducing component" in this specification is not particularly limited as long as it can reduce the metal components (for example, 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 employed as the reducing component. Carbon can be particularly preferably employed as the reducing component from the viewpoint that it is difficult to be oxidized and is stable until the start of the firing step S15. Further, various carbon materials (conductive materials, binders, negative electrode active materials, etc.) can be included in the type of the object to be recovered. By using these carbon materials as a supply source of the reducing component, it is possible to contribute to the reduction of the cost required for recovery.

[0025] The means for measuring the amount of substance of the reducing component (carbon element) in the object to be recovered is not particularly limited, and conventionally known measuring means can be used without particular limitation. For example, as the means for measuring the amount of substance of the carbon element, thermogravimetric differential thermal analysis (TG-DTA), SEM-EDS analysis, combustion-non-dispersive infrared analysis in an oxygen stream, volumetric combustion method, etc. can be mentioned.

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

[0027] Note that the means for measuring the amount of substance of the oxygen element in the recovery target is not limited to the above means, and conventionally known measurement means can be adopted without particular limitation. For example, the oxygen element in the recovery target may be directly measured using SEM-EDS analysis, XRF analysis, etc. By using these methods, even when the chemical composition of the positive electrode active material in the recovery target is unknown, the amount of substance of the oxygen element can be measured.

[0028] (c) Determination step S13 In the determination step S13, it is determined whether the molar 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 using carbon element as the reducing component, the above "oxide of the reducing component" becomes carbon dioxide (CO2). At this time, in the firing step S15 described later, in order to preferably reduce the metal component contained in the positive electrode active material, it is preferable to set the above threshold value to a value equal to or greater than the ratio (1 / 2) of the carbon element to the oxygen element in CO2. In the determination step S13, it is determined whether the molar ratio of the carbon element (reducing component) to the oxygen element in the object to be recovered (hereinafter, also referred to as "C / O ratio") is 1 / 2 or more. When the C / O ratio is 1 / 2 or more (YES in S13 of FIG. 4), the process proceeds to the firing step S15. On the other hand, when the C / O ratio is less than 1 / 2 (NO in S13 of FIG. 4), it is preferable to proceed to the reducing component addition step S14. Thereby, the metal component can be more preferably reduced to the state of the metal simple substance.

[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, still more preferably 5 / 4 or more, particularly preferably 3 / 2 or more). Thereby, only the object to be recovered containing a large amount of the reducing component (carbon element) can be supplied to the firing step S15, so that the reduction of the metal oxide in the firing step S15 can be further promoted.

[0030] (d) Reducing component addition step S14 The reducing component addition step S14 is a step of adding a reducing component to the object to be recovered when the determination result of the above determination step S13 is less than the threshold value (NO in S13 in FIG. 4). In the processing method disclosed herein, when the determination result of the determination step S13 is less than the threshold value, it is preferable to perform the reducing component addition step S14. For example, for an object to be recovered determined to have a C / O ratio of less than 1 / 2 in the determination step S13, it is preferable to add a reducing component (carbon-containing material) so that the C / O ratio becomes equal to or higher than the threshold value (1 / 2 or higher). Thereby, the metal component contained in the positive electrode active material can be more suitably reduced to the state of a simple metal. Here, 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. Also, the carbon-containing material may be a resin material such as polyolefin or polyester. Since these resin materials are carbonized at the initial stage of the firing step S15 to generate carbon elements, they can be used as a supply source of carbon elements.

[0031] In the reducing component addition step S14, a reducing component in an amount greatly exceeding the above threshold value may be added. For example, when the reducing component is a carbon element, a carbon-containing material may be added so that the C / O ratio in the object to be recovered becomes 3 / 4 or higher (more preferably 1 or higher, still more preferably 5 / 4 or higher, and particularly preferably 3 / 2 or higher). Thereby, since an object to be recovered containing a large amount of a reducing component (carbon element) can be subjected to the firing step S15, the reduction of the metal oxide in the firing step S15 can be further promoted.

[0032] (e) Firing step S15 In the firing step S15, the object to be recovered is fired (heated) at 850°C or higher. As a result, at least a part of the metal components (for example, Ni, Co, Mn, etc.) contained in the positive electrode active material can be reduced to the state of simple metals (for example, metallic Ni, metallic Co, metallic Mn, etc.). Then, these simple metals can be aggregated to increase the specific gravity. As a result, the metal components derived from the positive electrode active material are more likely to settle, and in the separation step S30 described later, the separability between the metal components and the carbon components contained in the negative electrode active material is improved. Therefore, it is possible to suitably achieve both an improvement in the carbon component recovery rate and a reduction in the loss rate of the metal components. For example, when the object to be recovered is fired at 850°C or higher in the firing step S15, a reaction as shown in the following formula (2) may occur. As a result, at least a part of the metal components contained in the positive electrode active material can be reduced to the state of simple metals.

[0033] LiNi x Co y Mn z O δ +C 1 / 2δ =Li+xNi+yCo+zMn+1 / 2δ·CO2(2)

[0034] The heating temperature (more specifically, the temperature inside the heating furnace) in the firing step S15 may be 850°C or higher. As the heating temperature increases, simple metals are more likely to be generated, and the simple metals tend to aggregate. As described above, when simple metals are generated and further aggregated, the specific gravity increases and the sedimentation property improves. In order to more efficiently separate the metal components and the carbon components in the separation step S30 described later, it is preferable that most of the metal components are reduced to the state of simple metals and the simple metals are preferably aggregated. Therefore, from this perspective, the heating temperature is preferably 875°C or higher, and may be 900°C or higher. On the other hand, from the perspective of reducing the metal components, 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 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, in the firing step S15, it is preferable to heat the object to be recovered in an inert atmosphere. By doing so, it is possible to prevent the supply of oxygen elements to the object to be recovered during heating, and more preferably, at least a part of the metal oxide (such as lithium transition metal composite oxide) can be reduced to the state of a simple metal. In addition, the carbon component can be minimized from being discharged as carbon dioxide, which is a greenhouse gas. Specifically, in the firing step S15, it is preferable to heat the object to be recovered while flowing an inert gas such as argon or nitrogen. Note that the "inert atmosphere" in this specification refers to a heating atmosphere mainly containing the above-mentioned inert gas. That is, it is not limited to a complete inert atmosphere in which the content of the inert gas is 100% (the content of oxygen elements is 0%), and a heating atmosphere in which the content of oxygen elements is 5% or less (preferably 3% or less, more preferably 1% or less, still more preferably 0.5% or less, and particularly preferably 0.1% or less) is also included.

[0036] The firing time in the firing step S15 varies depending on the amount of the object to be recovered and the like, and thus cannot be generally defined. The firing time in the firing step S15 is preferably, for example, 1 hour to 12 hours, and more preferably 2 hours to 8 hours.

[0037] (2) Sorting step S20 As shown in FIG. 3, it is preferable to perform the sorting step S20 after performing the heating step S10 in the processing method disclosed herein. In the sorting step S20, metal foils such as the positive electrode core 32 and the negative electrode core 42 included in the object to be recovered after the heating step S10 are physically removed and sorted. For the sorting step S20, for example, it is advisable to sort and remove the positive electrode core 32 and the negative electrode core 42 from the object to be recovered after firing using a sieve. Since the positive electrode core 32 and the negative electrode core 42 can be composed of metal foils as described above, they have a low specific gravity and tend to float together with graphite in the subsequent separation step S30. Therefore, by performing the sorting step S20 before the separation step S30 and reducing the content of the metal foil in the object to be recovered, graphite can be more suitably recovered in the separation step S30. Note that the sorting step S20 is not a step intended to completely remove metal foils such as the positive electrode core 32 and the negative electrode core 42 from the object to be recovered.

[0038] (3) Separation step S30 In the separation step S30, the metal component and the carbon component in the object to be recovered are separated and recovered respectively. In the separation step S30, a method of performing flotation on a slurry obtained by adding water to the object to be recovered after the heating step S10 or the object to be recovered after the sorting step S20 is preferably adopted. Flotation is a physical separation method in which hydrophobic components are attached to bubbles and floated, while hydrophilic components are sedimented. In flotation, hydrophobic components and hydrophilic components can be efficiently separated. In the processing method disclosed herein, the metal component is a hydrophilic component and the carbon component is a hydrophobic component. Therefore, by performing flotation on the slurry containing the object to be recovered, the carbon component (especially graphite) of the hydrophobic component can be floated, and the metal component (valuable metal) of the hydrophilic component can be sedimented, and they can be recovered in a separated state respectively.

[0039] In the separation step S30 using flotation, first, water is added to the material to be recovered after the heating step S10 or the material to be recovered after the sorting step S20 to prepare a slurry containing the material to be recovered. Next, a foaming agent and a collector are added to the slurry and stirred. Then, while introducing air into the slurry and stirring, the carbon component, which is a hydrophobic component, is attached to the bubbles and floated and recovered. On the other hand, since the residual slurry contains a metal component derived from the positive electrode active material, the slurry is recovered. Thereby, the carbon component and the metal component can be suitably separated and recovered respectively.

[0040] When separating and recovering the metal component derived from the positive electrode active material and the carbon component derived from the negative electrode active material by flotation, in order to remove the coating film, binder, etc. on the surface of the positive electrode active material and enhance the hydrophobicity, it is common to bake at a temperature of about 500°C. However, according to the studies of the present inventors, the positive electrode active material has a particle size of about 10 μm to 20 μm and a true density of 4.5 g / cm 3 Therefore, although it is easier to settle than the carbon material (especially graphite), it may float up together with the carbon material. On the other hand, in the treatment method disclosed herein, by heating (baking) at 850°C or higher, the metal component contained in the positive electrode active material is reduced (metallized) to the state of a single metal, and the specific gravity can be increased to about 8.9 g / cm 3 Furthermore, by aggregating the metallized metal components, the weight per metal particle can be increased, and the sedimentation property can be improved more than before. Therefore, it is possible to suppress the metal component from floating up together with the carbon component during the separation step S30 and reduce the loss rate of the metal component (the loss rate of the positive electrode active material). In addition, since the separability is improved, it can be carried out under the conditions of recovering the carbon component as much as possible, so the recovery rate of the carbon component is improved. Therefore, according to the treatment method disclosed herein, it is possible to suitably achieve both the reduction of the loss rate of the metal component and the improvement of the recovery rate of the carbon component.

[0041] The types of foaming agents and collectors used in flotation beneficiation are not particularly limited. The foaming agent has the function of dissolving in a solvent to generate bubbles and stabilizing the generated bubbles. Examples of the foaming agent include 4-methyl-2-pentanol (MIBC), pine oil, turpentine oil, etc. The amount of the foaming agent is not particularly limited, but in terms of the amount per ton (t) of the material to be recovered, it is preferably, for example, 50 to 200 g / t, and more preferably 100 to 150 g / t. The collector has the function of selectively adsorbing on the surface of the carbon material and enhancing the hydrophobicity of the surface. Examples of the collector include kerosene, heavy oil, etc. The amount of the collector is not particularly limited, but in terms of the amount per ton (t) of the material to be recovered, it is preferably, for example, 50 to 200 g / t, and more preferably 100 to 150 g / t.

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

[0043] As described above, the method for treating battery members according to this embodiment has been described. As described above, in the treatment method disclosed herein, by firing the material to be recovered at 850 °C or higher, the separability between the metal components contained in the positive electrode active material and the carbon components contained in the negative electrode active material is improved, and each can be suitably recovered. Note that the technology disclosed herein is not limited to the above-described embodiment, and includes other embodiments in which various configurations are changed.

[0044] [Test Example] Hereinafter, test examples related to the technology disclosed herein will be described. 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, the mixture of the positive electrode plate and the negative electrode plate was the object to be recovered, 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 O2). The negative electrode plate was prepared by coating a negative electrode active material layer on the surface of a negative electrode core (Cu foil). The negative electrode active material in the negative electrode active material was graphite. Then, this secondary battery (the mixture of the positive electrode plate and the negative electrode plate) was crushed to prepare a powder sample.

[0046] Next, a part of the prepared powder sample was collected and dissolved in sulfuric acid. Then, ICP was performed on the dissolved solution to measure the total amount of substances M of Ni, Co, and Mn. And based on the composition of the positive electrode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2), the amount of substance twice the total amount of substances M was defined as the amount of substance N of oxygen element (N = 2M). Also, in this test, thermogravimetric differential thermal analysis (TG-DTA) was performed on a part 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. Thereby, the amount of carbon in the prepared powder sample was measured. And it was examined whether the measured molar ratio of carbon element to oxygen element (C / O ratio) was equal to or greater than the stoichiometric ratio (1 / 2) of CO2. 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 in 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 at this time was set to 5°C / min. Then, heating was performed for 5 hours while maintaining the furnace temperature at 1000°C. After that, after cooling the furnace temperature to 50°C, the powder sample of Example 1 was recovered.

[0048] The recovered powder sample was sieved through a sieve with an aperture of 500 μm to obtain a post-heating sample. 25 g of the post-heating sample was fed into a flotation cell and conditioned (mixed) at a rotational speed of 700 rpm for 5 minutes. Subsequently, 3.1 mL of kerosene (100 g / t in solid content) as a collector was added, and the slurry was conditioned for 3 minutes. Next, 3.1 mL of 4-methyl-2-pentanol (MIBC) as a frother was added, and the slurry was conditioned for 2 minutes. Thereafter, air was supplied at a blowing rate of 2 L / min, and flotation separation was carried out. During the 1-minute flotation separation, the generated foam was recovered. The recovered foam was washed with water to obtain the sample of Example 1.

[0049] (Examples 2 to 6) In Examples 2 to 6, the furnace temperature was changed as shown in Table 1. Except for this, the samples of Examples 2 to 6 were obtained in the same manner as in Example 1. In addition, in the powder samples of Examples 2 to 6, the measured molar ratio of oxygen element to carbon element (C / O ratio) was also equal to or higher than the stoichiometric ratio (1 / 2) of CO2.

[0050] (Example 7) In Example 7, as the object to be recovered, a secondary battery (a mixture of a positive electrode plate and a negative electrode plate) similar to that in Example 1 was prepared. Such a secondary battery was crushed to prepare a powder sample sieved through a sieve with an aperture of 500 μm. 25 g of the powder sample was fed into a flotation cell, and flotation separation was carried out under the same conditions as in Example 1 to obtain the sample of Example 7. That is, in Example 7, flotation separation was carried out without heating the powder sample.

[0051] 2. Evaluation test (1) Calculation of the recovery rate of the carbon component TG-DTA analysis was carried out on the flotation samples after flotation separation in each example to calculate the recovery rate of the carbon component in each example. Specifically, after drying the flotation samples after flotation separation in each example, the carbon amount was calculated from the weight loss amount of TG-DTA. By dividing the carbon amount by the carbon amount in the sample fed into the flotation cell, the recovery rate of the carbon component in each example was calculated. The results are shown in Table 1.

[0052] (2) Calculation of the loss rate of the metal component ICP analysis was performed on the sedimentation samples after flotation separation for each example, and the loss rate of the metal component for each example was calculated. Specifically, after drying the sedimentation samples after flotation separation for each example, they were dissolved in acid and subjected to ICP analysis to calculate the amount of metal derived from the positive electrode active material in the sample. 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 recovery rate of the metal component for each example was calculated. By subtracting the recovery rate of the metal component for each example from 100 (%), the loss rate of the metal component for each example was calculated. The results are shown in Table 1.

[0053]

Table 1

[0054] As shown in Table 1, it can be seen that in Examples 1 to 3, the recovery rate of the carbon component is 90% or more and the loss rate of the metal component is 4% or less. This is presumably because by heating the powder sample at 850 °C or higher, most of the metal components are reduced to the state of simple metals, and the reduced metal components aggregate to increase the specific gravity and improve the sedimentation property. And by performing the separation step after the heating step, the separability between the metal component and the carbon component is improved, and it is presumed that even with a high recovery rate of the carbon component, the loss rate of the metal component can be kept low.

[0055] Although the technologies disclosed herein have been described in detail above, these are merely examples and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes of the specific examples exemplified above. That is, the technologies disclosed herein include the forms described in Items 1 to 6 below.

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

[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. The treatment method according to Item 1, further including a sorting step of sorting the metal foil contained in the object to be recovered before the separation step.

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

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

[0060] <Item 5> The heating step includes a reducing component addition step of adding the reducing component so that the amount of substance of the reducing component is equal to or greater than a threshold value based on the stoichiometric ratio of the oxide of the reducing component with respect to the amount of substance of the oxygen element contained in the object to be recovered. The treatment method according to any one of Items 1 to 4.

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

Explanation of Reference Numerals

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

Claims

1. A heating step of heating a recovery target containing a positive electrode including a lithium transition metal composite oxide having at least 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 a slurry containing the recovery target after the heating step to separate a metal component and a carbon component contained in the recovery target; comprising: In the heating step, based on the amount of substance of the oxygen element contained in the recovery target, the amount of substance of the reducing component is added such that the amount of the reducing component is equal to or greater than a threshold value based on the stoichiometric ratio of the oxide of the reducing component, A method for treating battery members, including a reducing component adding step of adding the reducing component.

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 treatment method according to claim 1, further comprising a sorting step of sorting the metal foil contained in the recovery target before the separation step.

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

4. The treatment method according to claim 1, wherein the heating step is carried out in an inert atmosphere.

5. The reducing component is a carbon element, and the threshold value is a value equal to or greater than the stoichiometric ratio of CO ２ The treatment method according to claim 1, which is a value equal to or greater than the stoichiometric ratio of

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