Method for processing battery component

Abstract

Provided is a method for processing a battery member, which improves the recovery rate of a carbon component and reduces the loss rate of a metal component. A treatment method disclosed herein includes: a heating step S10 in which a recovery target containing at least a positive electrode containing a lithium transition metal composite oxide having a layered structure and a negative electrode containing a carbon material is heated at 850 DEG C or higher; and a separation step (S30) in which a foaming agent and a collecting agent are added to the slurry containing the object to be recovered after the heating step (S10), and a metal component and a carbon component contained in the object to be recovered are separated.

Description

Technical Field

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

[0002] Lithium ion secondary batteries are widely used in various fields. The lithium ion secondary batteries use various materials including metal components such as Ni, Co, and Mn, and carbon components such as graphite. For example, the positive electrode active material uses lithium transition metal composite oxides such as lithium nickel composite oxide, lithium cobalt composite oxide, and lithium nickel cobalt manganese composite oxide. In addition, aluminum foil is used for the positive electrode core. On the other hand, carbon materials are used for the negative electrode active material. In addition, copper foil is used for the negative electrode core.

[0003] In recent years, research is being conducted on recycling technologies that recycle metal components and carbon components from used batteries, processing waste, etc. and reuse them as battery materials. For example, in non-patent literature 1 (Ruiting Zhan, Zachary Oldenburg, Lei Pan, Recovery of active cathode materials from lithium-ion batteries using froth flotation, Sustainable Materials and Technologies 17, September 2018), a technology is disclosed in which a slurry containing a recycling object is filtered and calcined at 500° C., and then flotation separation is performed to separate positive electrode active material and graphite. Summary of the invention

[0004] Non-patent document 1 states 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 is a trend to establish a high resource recovery rate (95% or more), requiring both an increase in the recovery rate of the carbon component and a decrease in the loss rate of the metal component contained in the positive electrode active material. In particular, the loss rate of the metal component is preferably 5% or less.

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

[0006] The battery component processing method disclosed in this article includes the following steps: a heating step, heating the recycling object at above 850°C, wherein the recycling object at least contains: a positive electrode comprising a lithium transition metal composite oxide with a layered structure, and a negative electrode comprising a carbon material; and a separation step, adding a foaming agent and a collecting agent to the slurry of the recycling object after the above heating step, so as to separate the metal components and carbon components contained in the above recycling object.

[0007] In the treatment method of the above structure, by heating the recovery object at 850°C or above, the metal component in the recovery object can be reduced to the state of a metal single substance. Moreover, since the metal single substance is condensed, the specific gravity can be appropriately increased. As a result, the sedimentation of the metal component is improved, and the separation from the carbon component is improved. Therefore, the metal component and the carbon component can be appropriately separated in the separation process, and the recovery rate of the carbon component and the loss rate of the metal component can be appropriately improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a longitudinal cross-sectional view schematically showing the internal structure of a lithium-ion secondary battery.

[0009] Figure 2 It is schematically indicated Figure 1 A perspective view of an electrode body of a lithium-ion secondary battery shown.

[0010] Figure 3 1 is a flowchart illustrating a method for handling a battery component according to an embodiment.

[0011] Figure 4 This is a flowchart illustrating in detail a heating step in a treatment method according to one embodiment.

[0012] Explanation of symbols

[0013] 1Lithium-ion secondary battery

[0014] 10 Shell

[0015] 12 Positive terminal

[0016] 14 Negative terminal

[0017] 20 electrode body

[0018] 30 positive plate

[0019] 32 positive electrode core

[0020] 34 Positive electrode active material layer

[0021] 40 negative plate

[0022] 42 negative electrode core

[0023] 44 Negative electrode active material layer

[0024] 50 Isolators DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. It should be noted that matters other than those specifically mentioned in this specification and matters required for the implementation of the technology disclosed herein can be grasped as design matters for those skilled in the art based on the prior art in this field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in this field.

[0026] 1. Recycling objects

[0027] The method for processing battery components disclosed herein is a method for separating and recovering metal components such as Ni, Co, and Mn and carbon components such as graphite from a specified recycling object. The recovered metal components and carbon components can be appropriately used as materials for positive electrode active materials and / or negative electrode active materials of lithium ion secondary batteries. As an example of the recycling object here, a used lithium ion secondary battery can be cited. The lithium ion secondary battery is specifically described below. Figure 1 It is a longitudinal cross-sectional view schematically showing the internal structure of a lithium-ion secondary battery. Figure 2 It is schematically indicated Figure 1 A perspective view of an electrode body of a lithium-ion secondary battery shown.

[0028] like Figure 1 As shown, the lithium ion secondary battery 1 includes a case 10 , an electrode body 20 , and an electrolyte (not shown).

[0029] (1) Housing

[0030] The housing 10 is a box-shaped container. The electrode body 20 and the electrolyte are contained in the housing 10. The housing 10 is made of a metal material (aluminum (Al) or the like) having a certain strength. In addition, a positive terminal 12 and a negative terminal 14 are installed in the housing 10. The positive terminal 12 and the negative terminal 14 are connected to the electrode body 20 in the housing 10. Specifically, the positive terminal 12 is connected to the positive electrode plate 30 (see Figure 2 ) is connected. The positive terminal 12 is made of aluminum (Al) or the like. On the other hand, the negative terminal 14 is connected to the negative electrode plate 40 (see Figure 2 The negative electrode terminal 14 is made of copper (Cu) or the like.

[0031] (2) Electrode body

[0032] The electrode body 20 is a power generation element of the lithium ion secondary battery 1. Figure 2 As shown, the electrode body 20 includes a positive electrode plate 30, a negative electrode plate 40 and a separator 50. Figure 2The electrode body 20 shown here is a wound electrode body. The wound electrode body is made 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. The structure of the electrode body 20 is not particularly limited, and can be other structures that have been known to the public (laminated electrode body, etc.).

[0033] The positive electrode plate 30 includes: a positive electrode core 32 as 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 (e.g., aluminum foil). In addition, the positive electrode active material layer 34 is a mixture layer containing a positive electrode active material, a conductive material, a binder, etc. The positive electrode active material is preferably a lithium transition metal composite oxide having a layered structure. As an example of the lithium transition metal composite oxide having a layered structure, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel manganese cobalt composite oxide, etc. can be cited. According to the processing method involved in this embodiment, metal components (precious metals) such as Ni, Co, and Mn can be efficiently recovered from the recycling object containing such a lithium transition metal composite oxide having a layered structure. In addition, as the conductive material contained in the positive electrode active material layer 34, carbon materials such as acetylene black and graphite can be cited. In addition, as the binder contained in the positive electrode active material layer 34, resin materials such as polyvinylidene fluoride (PVdF) can be cited.

[0034] The negative electrode plate 40 includes: a negative electrode core 42 which is a metal foil having conductivity, and a negative electrode active material layer 44 provided on the surface of the negative electrode core 42. The negative electrode core 42 is made of a metal foil (e.g., copper foil). In addition, the negative electrode active material layer 44 is a composite layer containing a negative electrode active material, a binder, a thickener, etc. The negative electrode active material contains a carbon material. Examples of the carbon material include graphite, hard carbon, and soft carbon. In addition, the negative electrode active material may contain silicon (Si), a composite containing carbon and silicon (SiC), silicon oxide (SiO X ) etc. Among them, the negative electrode active material preferably includes graphite. As a binder included in the negative electrode active material layer, a resin material such as styrene-butadiene rubber (SBR) can be cited. As a thickener included in the negative electrode active material layer, a resin material such as carboxymethyl cellulose (CMC) can be cited.

[0035] In addition, the separator 50 is an insulating sheet sandwiched between the positive electrode plate 30 and the negative electrode plate 40. The separator 50 uses, for example, a resin material such as polyethylene (PE), polypropylene (PP), polyester, cellulose, polyamide, etc. In addition, a heat-resistant layer containing an inorganic filler can be formed on the surface of the separator 50. Examples of the inorganic filler 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.

[0036] (3) Electrolytes

[0037] The electrolyte is present between the positive electrode plate 30 and the negative electrode plate 40. This enables the charge carrier (Li ion) to move between the positive electrode plate 30 and the negative electrode plate 40. As an example of the electrolyte, a non-aqueous electrolyte, a gel electrolyte, etc. can be cited. It should be noted that the electrolyte can be used without particular limitation for an electrolyte that can be used in a lithium ion secondary battery, and the technology disclosed herein is not limited.

[0038] As an example of a recycling object in the treatment method involved in the present embodiment, a lithium-ion secondary battery 1 is described above. However, the treatment method disclosed herein is not limited to a method in which the lithium-ion secondary battery 1 of the above-mentioned structure is used as a recycling object. For example, at the manufacturing site of lithium-ion secondary batteries, sometimes the electrode body after production has some defects and cannot be used in products. Since such an electrode body also contains metal components (precious metals) such as Ni and Co from the positive electrode active material and carbon materials such as graphite from the negative electrode active material, it can also be a recycling object. Alternatively, the electrode body taken out by decomposing the used secondary battery can also be a recycling object because it contains metal components such as Ni and Co from the positive electrode active material and carbon components such as graphite from the negative electrode active material. That is, the recycling object of the treatment 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.

[0039] 2. Processing methods of battery components

[0040] The following is an explanation of the method for processing the battery components disclosed in this article. Figure 3 is a flow chart illustrating the processing method disclosed herein. Figure 4 It is detailed description Figure 3Flowchart of the heating process in . The processing method of the battery component disclosed in this article includes at least a heating process S10 and a separation process S30. In the separation process S30, the hydrophilicity of the metal component and the hydrophobicity of the carbon component are used to physically screen the metal component and the carbon component and recover them separately, and the details are described below. The processing method disclosed in this article may further include a screening process S20. According to the processing method disclosed in this article, the sedimentation property of the metal component is improved, thereby improving the separation property of the metal component and the carbon component in the separation process S30. As a result, it is possible to appropriately achieve an increase in the recovery rate of the carbon component and a decrease in the loss rate of the metal component.

[0041] It should be noted that in this specification, the "recovery rate of carbon components" refers to the amount of carbon recovered in the separation process relative to the amount of carbon in the recovery object supplied to the separation process. The carbon amount can be calculated, for example, by thermogravimetric differential thermal analysis (TG-DTA). In addition, the "loss rate of metal components" refers to the amount of metal recovered in the separation process relative to the amount of metal in the recovery object supplied to the separation process, and the value obtained by subtracting the value from 100%. The metal amount can be calculated, for example, by inductively coupled plasma mass spectrometry (ICP: Inductively Coupled Plasma).

[0042] (1) Heating step S10

[0043] In the heating step S10, the above-mentioned recycling object is heated at 850°C or above. In the recycling object, the metal components (such as 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 recycling object at 850°C or above, the metal components can be appropriately reduced to the state of metal elements (metal Ni, metal Co, metal Mn). Moreover, by heating at least at 850°C or above, the reduced metal elements can be condensed, the specific gravity of the metal components can be increased, and thus the sedimentation properties can be improved. As a result, in the separation step S30 described later, the separation properties of the metal components and the carbon components can be appropriately improved.

[0044] In the heating step S10, by heating the above-mentioned recycling object, the liquid components (electrolyte, etc.) in the recycling object and the film on the surface of the positive electrode active material can be appropriately removed. In addition, the resin components (binders, separators, etc.) contained in the recycling object can also be carbonized. When the charged lithium-ion secondary battery 1 is used as the recycling object, the function as a battery can be stopped by implementing the heating step S10. In this way, the next step can be safely implemented. Figure 4 As shown, the heating step S10 may include a preparation step S11, a measurement step S12, a determination step S13, a reducing component adding step S14, and a calcination step S15, but is not particularly limited.

[0045] (a) Preparation Step S11

[0046] In the preparation step S11, a recycling object is prepared, and the recycling object at least includes: a positive electrode including a layered lithium transition metal composite oxide and a negative electrode including a carbon material. As described above, the "recycling object" in the technology disclosed herein is not limited to a completed lithium-ion secondary battery, but also includes defective parts (electrode bodies, etc.), electrode bodies after battery disassembly, etc. It should be noted that the details of the recycling object have been described, so repeated descriptions are omitted.

[0047] (b) Measurement step S12

[0048] In the measuring step S12, the amount of oxygen element (O) and the reducing component contained in the recycling object is measured. In the measuring step S12, a part of the recycling object can be taken as a sample for measurement, and the oxygen element and the reducing component of the sample for measurement can be measured. In addition, the measuring step S12 can be implemented only when the type of recycling object is changed, and it is not necessary to implement it for all the prepared recycling objects. This can improve the processing efficiency.

[0049] It should be noted that the "reducing component" in this specification is not particularly limited as long as it is a component that can reduce the metal components (for example, Ni, Co, Mn, etc.) contained in the positive electrode active material in the calcination step S15 described later. In the treatment method disclosed herein, carbon element (C) is preferably used as the reducing component. From the perspective of being less prone to oxidation and more stable until the start of the calcination step S15, it is particularly preferred to use carbon as the reducing component. In addition, the types of recycling objects may include various carbon materials (conductive materials, binders, negative electrode active materials, etc.). By using these carbon materials as a supply source of reducing components, it helps to reduce the cost required for recycling.

[0050] The method for measuring the amount of the reducing component (carbon element) in the recovery object is not particularly limited, and the known measurement method can be used without particular limitation. For example, as a method for measuring the amount of carbon element, thermogravimetric differential thermal analysis (TG-DTA), SEM-EDS analysis, combustion oxidation-non-dispersive infrared absorption method, combustion volume method, etc. can be cited.

[0051] Next, a method for determining the amount of oxygen element in the recycling object is described. First, when the chemical composition of the positive electrode active material in the recycling object is known in advance, the amount of metal element in the recycling object can be determined, and the amount of oxygen element can be calculated based on the amount of metal element. In this way, the amount of oxygen element in the metal oxide (for example, a lithium transition metal composite oxide having a layered structure) can be easily determined. A specific example of the measurement step is as follows. First, a solution in which a part of the recycling object (the sample for measurement) is dissolved in an acid is prepared. Next, the solution is subjected to inductively coupled plasma mass spectrometry (ICP: Inductively Coupled Plasma). In this way, the total amount M of transition metal elements (Ni, Co, Mn) in the recycling object can be determined. Then, after the chemical composition of the positive electrode active material in the recycling object (LiNi x Co y Mn z O δ ), the ratio (x+y+z:δ) of the total amount of transition metal elements (x+y+z) to the amount of O (δ) can be determined. In this case, the amount of oxygen element N can be calculated from the ICP measurement result (the total amount of metal elements M) based on the following formula (1).

[0052] N=δ·M / (x+y+z) (1)

[0053] It should be noted that the method for determining the amount of oxygen in the recovered object is not limited to the above method, and a known determination method can be used without particular limitation. For example, SEM-EDS analysis, XRF analysis, etc. can be used to directly determine the oxygen in the recovered object. By using these methods, the amount of oxygen can be determined even when the chemical composition of the positive electrode active material in the recovered object is unknown.

[0054] (c) Determination step S13

[0055] In the determination step S13, it is determined whether the amount ratio of the reducing component to the oxygen element is above 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 is used as the reducing component, the "oxide of the reducing component" is carbon dioxide (CO2). At this time, in the calcination step S15 described later, in order to properly reduce the metal components contained in the positive electrode active material, it is preferred to set the threshold value to a value greater than the ratio of the carbon element to the oxygen element in CO2 (1 / 2). In the determination step S13, it is determined whether the amount ratio of the carbon element (reducing component) to the oxygen element in the recovery object (hereinafter also referred to as "C / O ratio") is above 1 / 2. When the C / O ratio is above 1 / 2 ( Figure 4On the other hand, when the C / O ratio is less than 1 / 2 ( Figure 4 If the step S13 is not performed, it is preferred to proceed to the reducing component adding step S14. Thus, the metal component can be more appropriately reduced to a state of a metal single substance.

[0056] It should be noted that, as described above, the threshold value in this step can be set to a value greater than the stoichiometric ratio of the oxide of the reducing component. For example, when the reducing component is carbon, the threshold value can be set to 3 / 4 or more (more preferably 1 or more, further preferably 5 / 4 or more, and particularly preferably 3 / 2 or more). Thus, only the recovery object containing a large amount of reducing component (carbon element) can be supplied to the calcining step S15, so the reduction of the metal oxide in the calcining step S15 can be further promoted.

[0057] (d) Reducing component adding step S14

[0058] The reducing component adding step S14 is performed when the determination result of the determination step S13 is lower than the threshold value ( Figure 4 In the treatment method disclosed herein, when the determination result of the above-mentioned determination step S13 is lower than the threshold value, the reducing component adding step S14 is preferably implemented. For example, it is preferred to add reducing components (carbon-containing materials) to the recycling object determined as having a C / O ratio less than 1 / 2 in the determination step S13 in such a way that the C / O ratio becomes above the threshold value (above 1 / 2). Thereby, the metal components contained in the positive electrode active material can be more appropriately reduced to the state of a metal single substance. It should be noted that as the carbon-containing material here, carbon materials such as graphite, hard carbon, and soft carbon can be cited. For example, a negative electrode plate 40 containing carbon materials such as graphite can also be further added. In addition, the carbon-containing material can be a resin material such as polyolefin and polyester. These resin materials produce carbon elements due to the initial carbonization in the calcination step S15, and therefore can be used as a supply source of carbon elements.

[0059] In the reducing component adding step S14, a reducing component in an amount far exceeding the above threshold value may be added. For example, when the reducing component is carbon, the carbon-containing material may be added in such a manner that the C / O ratio in the recovery object becomes 3 / 4 or more (more preferably 1 or more, further preferably 5 / 4 or more, and particularly preferably 3 / 2 or more). Thus, the recovery object containing a large amount of reducing components (carbon elements) can be supplied to the calcining step S15, thereby further promoting the reduction of the metal oxide in the calcining step S15.

[0060] (e) Calcination step S15

[0061] In the calcination step S15, the recovery object is calcined (heated) at a temperature above 850°C. Thus, at least a portion of the metal components (e.g., Ni, Co, Mn, etc.) contained in the positive electrode active material can be reduced to a state of a metal single substance (e.g., metal Ni, metal Co, metal Mn, etc.). Moreover, these metal single substances can be condensed to increase the specific gravity. As a result, the metal components from the positive electrode active material are easily precipitated, and in the separation step S30 described later, the separation of the metal components from the carbon components contained in the negative electrode active material is improved. Therefore, it is possible to appropriately achieve both an increase in the recovery rate of the carbon component and a reduction in the loss rate of the metal component. For example, in the calcination step S15, when the recovery object is calcined at a temperature above 850°C, a reaction as shown in the following formula (2) will occur. Thus, at least a portion of the metal components contained in the positive electrode active material can be reduced to a state of a metal single substance.

[0062] LiNi x Co y Mn z O δ +C 1 / 2δ =Li+xNi+yCo+zMn+1 / 2δ·CO2 (2)

[0063] The heating temperature in the calcination step S15 (more specifically, the temperature in the heating furnace) only needs to be above 850°C. There is a tendency that a metal single substance is easily generated as the heating temperature rises, and the metal single substance is easily condensed. As described above, since a metal single substance is generated and then condensed, the specific gravity increases and the sedimentation property is improved. In order to more efficiently separate the metal component and the carbon component in the separation step S30 described later, it is preferred that most of the metal component is reduced to a state of a metal single substance, and the metal single substance is appropriately condensed. Therefore, from this point of view, the heating temperature is preferably above 875°C, and can be above 900°C. On the other hand, from the point of view of the reduction of the metal component, the upper limit of the heating temperature is not particularly limited, and can be below 1500°C, below 1400°C, or below 1300°C. It should be noted that from the perspective of reducing the cost required for the calcination step S15, the upper limit of the heating temperature is preferably below 1200°C, more preferably below 1100°C, and particularly preferably below 1000°C.

[0064] Although not particularly limited, it is preferred that the calcination step S15 heats the recovery object under an inactive environment. In this way, it is possible to prevent the oxygen element from being supplied to the recovery object being heated, and it is possible to more appropriately reduce at least a portion of the metal oxide (lithium transition metal composite oxide, etc.) to a state of a metal single substance. In addition, the carbon component can be discharged in the form of greenhouse gas carbon dioxide to a minimum. Specifically, the calcination step S15 preferably heats the recovery object under the circulation of an inactive gas such as argon or nitrogen. It should be noted that the "inactive environment" in this specification refers to a heating environment containing the above-mentioned inactive gas as the main component. That is, it is not limited to a completely inactive environment with an inactive gas content of 100% (oxygen content of 0%), but also includes a heating environment with an oxygen content of less than 5% (preferably less than 3%, more preferably less than 1%, further preferably less than 0.5%, and particularly preferably less than 0.1%).

[0065] The calcination time in the calcination step S15 varies depending on the amount of the recovery target, etc., and therefore cannot be determined in general. The calcination time in the calcination step S15 is, for example, preferably 1 to 12 hours, and more preferably 2 to 8 hours.

[0066] (2) Screening step S20

[0067] like Figure 3 As shown, the treatment method disclosed herein preferably implements the screening step S20 after the heating step S10. In the screening step S20, the metal foils such as the positive electrode core 32 and the negative electrode core 42 contained in the recycling object after the heating step S10 are physically removed for screening. The screening step S20 can, for example, use a sieve to screen the positive electrode core 32 and the negative electrode core 42 from the recycling object after calcination and remove them from the recycling object. As described above, the positive electrode core 32 and the negative electrode core 42 are composed of metal foil, so there is a tendency to float with graphite in the separation step S30 described later because of their light specific gravity. Therefore, by implementing the screening step S20 before the separation step S30 to reduce the content of metal foil in the recycling object, graphite can be more appropriately recovered in the separation step S30. It should be noted that the screening step S20 is not a step intended to completely remove the metal foils such as the positive electrode core 32 and the negative electrode core 42 from the recycling object.

[0068] (3) Separation step S30

[0069] In the separation process S30, the metal component and the carbon component in the recovery object are separated and recovered separately. In the separation process S30, it is preferred to adopt a method of flotation separation of the slurry obtained by adding water to the recovery object after the heating process S10 or the recovery object after the screening process S20. Flotation separation (flotation) is a physical screening in which bubbles are attached to the hydrophobic component to make it float and the hydrophilic component is settled on the other hand. Flotation separation can efficiently separate the hydrophobic component from the hydrophilic component. In the treatment method disclosed herein, the metal component is the hydrophilic component and the carbon component is the hydrophobic component. Therefore, by subjecting the slurry containing the recovery object to flotation separation, the carbon component (especially graphite) of the hydrophobic component can be floated and the metal component (precious metal) of the hydrophilic component can be settled, thereby recovering them separately in a separated state.

[0070] In the separation process S30 using flotation beneficiation, first, water is added to the recovery object after the heating process S10 or the recovery object after the screening process S20 to prepare a slurry containing the recovery object. Next, a frother and a collector are added to the slurry and stirred. Then, by introducing air into the slurry while stirring, the bubbles are attached to the carbon component as a hydrophobic component to float and recover it. On the other hand, since the residual slurry contains metal components from the positive electrode active material, the slurry is recovered. Thus, the carbon component and the metal component can be properly separated and recovered separately.

[0071] When the metal components from the positive electrode active material and the carbon components from the negative electrode active material are separated and recovered by flotation, in order to remove the film and binder on the surface of the positive electrode active material and improve the hydrophobicity, it is generally calcined at a temperature of about 500°C. However, according to the research of the present inventors, since the particle size of the positive electrode active material is about 10μm to 20μm and the true density is 4.5g / cm 3 Therefore, although it is easier to settle than carbon materials (especially graphite), it may float together with carbon materials. In contrast, in the treatment method disclosed in this article, by heating (calcining) at 850°C or above, the metal components contained in the positive electrode active material can be reduced to a state of a metal single substance (metallization), and the specific gravity can be increased to 8.9g / cm 3 About. Furthermore, by agglomerating the metalized metal components, the weight of each metal particle is increased, so that the sedimentation property can be improved compared with the past. Therefore, during the separation process S30, the metal components can be suppressed from floating together with the carbon components, and the loss rate of the metal components (the loss rate of the positive electrode active material) can be reduced. In addition, by improving the separability, it can be implemented under the condition of recovering the carbon components as much as possible, so the recovery rate of the carbon components is improved. Therefore, according to the treatment method disclosed in this article, it is possible to appropriately achieve both the reduction of the loss rate of the metal components and the improvement of the recovery rate of the carbon components.

[0072] There is no particular limitation on the types of frothers and collectors used in flotation beneficiation. The frother has the function of dissolving in a solvent to generate bubbles and stabilizing the generated bubbles. As the frother, for example, 4-methyl-2-pentanol (MIBC), pine oil, turpentine, etc. can be cited. The amount of the frother is not particularly limited, and is preferably 50 to 200 g / t, and more preferably 100 to 150 g / t, relative to 1 ton (t) of the recovery object. The collector has the function of selectively adsorbing on the surface of the carbon material to increase the hydrophobicity of its surface. As the collector, for example, kerosene, heavy oil, etc. can be cited. The amount of the collector is not particularly limited, and is preferably 50 to 200 g / t, and more preferably 100 to 150 g / t, relative to 1 ton (t) of the recovery object.

[0073] By appropriately drying the carbon material recovered in the separation step S30, it can be used as a battery material (negative electrode material). In addition, the metal component recovered in the separation step S30 can be separated into each metal by appropriately implementing the same steps as the existing method such as the acid leaching step, the neutralization precipitation step, and the solvent extraction step, and can be appropriately used as a battery material (positive electrode material).

[0074] The above is a description of the processing method of the battery components involved in this embodiment. As described above, in the processing method disclosed herein, by calcining the recovery object at 850°C or above, the separation of the metal component contained in the positive electrode active material and the carbon component contained in the negative electrode active material can be improved, and they can be appropriately recovered separately. It should be noted that the technology disclosed herein is not limited to the above-mentioned embodiment, and also includes other embodiments in which various structures are changed.

[0075] [Test example]

[0076] The following describes test examples related to the technology disclosed herein. It should be noted that the content of the test examples described below is not intended to limit the technology disclosed herein.

[0077] 1. Preparation of test samples

[0078] (Example 1) In this test, a mixture of positive and negative plates was used as the recycling object, and the test samples were prepared according to the following steps. First, a secondary battery to be recycled was prepared. For the positive plate of the secondary battery, a material in which a positive electrode active material layer was arranged on the surface of the positive electrode core (Al foil) was prepared. 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 / 3O2). For the negative electrode plate, a negative electrode active material layer is coated on the surface of the negative electrode core (Cu foil). The negative electrode active material in the negative electrode active material layer is graphite. Then, the secondary battery (a mixture of the positive electrode plate and the negative electrode plate) is crushed to prepare a powder sample.

[0079] Next, a portion of the powder sample prepared above was taken and dissolved in sulfuric acid. Then, ICP was performed on the solution to measure the total mass M of Ni, Co and Mn. Then, based on the composition of the positive electrode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2), and the amount of twice the total amount M is taken as the amount N of oxygen element (N=2M). In addition, in this experiment, thermogravimetric differential thermal analysis (TG-DTA) is performed on a part of the powder sample. In this thermogravimetric differential thermal analysis, the powder sample is heated in an atmospheric environment at 800°C. It should be noted that in this analysis, the heating rate from room temperature (20°C) to 800°C is set to 5°C / min. The carbon amount in the powder sample prepared above is thus determined. Then, it is investigated whether the measured amount ratio (C / O ratio) of carbon element to oxygen element is greater than the stoichiometric ratio (1 / 2) of CO2. As a result, in the powder of Example 1, the above C / O ratio is greater than 1 / 2.

[0080] Next, the powder sample is heated in an inactive environment. Specifically, in Example 1, the powder sample is placed in an electric furnace, and the temperature in the furnace is raised to 1000°C while supplying Ar gas. It should be noted that the heating rate at this time is set to 5°C / min. Then, heating is performed for 5 hours while maintaining the temperature in the furnace at 1000°C. Thereafter, the powder sample of Example 1 is recovered after the temperature in the furnace is cooled to 50°C.

[0081] The above-mentioned recovered powder sample is passed through a sieve with an aperture of 500 μm to prepare a heated sample. 25 g of the heated sample is supplied to a flotation separation tank and trimmed (mixed) at a rotation speed of 700 rpm for 5 minutes. Next, 3.1 mL of kerosene (100 g / t in terms of solid content) is added as a collector, and the slurry is trimmed for 3 minutes. Then 3.1 mL of 4-methyl-2-pentanol (MIBC) (100 g / t in terms of solid content) is added as a foaming agent, and the slurry is trimmed for 2 minutes. Thereafter, air is supplied at a blowing amount of 2 L / min to implement flotation separation. During 1 minute of flotation separation, the generated bubbles are recovered. The recovered bubbles are washed with water to obtain the sample of Example 1.

[0082] (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. It should be noted that in the powder samples of Examples 2 to 6, the measured mass ratio of carbon element to oxygen element (C / O ratio) was also greater than the stoichiometric ratio (1 / 2) of CO2.

[0083] (Example 7) In Example 7, the same secondary battery (mixture of positive and negative plates) as in Example 1 was prepared as a recycling object. The secondary battery was crushed and passed through a sieve with an aperture of 500 μm to prepare a powder sample. 25 g of the powder sample was supplied to a flotation separation tank, and flotation separation was performed under the same conditions as in Example 1 to obtain a sample of Example 7. That is, in Example 7, flotation separation was performed without heating the powder sample.

[0084] 2. Evaluation test

[0085] (1) Calculation of carbon component recovery rate

[0086] The floatation samples after the floatation beneficiation of each example were subjected to TG-DTA analysis to calculate the recovery rate of the carbon component of each example. Specifically, the floatation samples after the floatation beneficiation of each example were dried, and the carbon content was calculated from the weight loss of TG-DTA. The carbon content was divided by the carbon content in the sample supplied to the floatation beneficiation tank to calculate the recovery rate of the carbon component of each example. The results are shown in Table 1.

[0087] (2) Calculation of metal component loss rate

[0088] ICP analysis was performed on the sedimentation samples after flotation beneficiation of each example, and the loss rate of the metal components of each example was calculated. Specifically, the sedimentation samples after flotation beneficiation of each example were dried, acid-dissolved, and then ICP analysis was performed to calculate the amount of metal from the positive electrode active material in the sample. The amount of metal was divided by the amount of metal from the positive electrode active material in the sample supplied to the flotation beneficiation tank to calculate the recovery rate of the metal components of each example. The recovery rate of the metal components of each example was subtracted from 100 (%) to calculate the loss rate of the metal components of each example. The results are shown in Table 1.

[0089] [Table 1]

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[0091]

[0092] As shown in Table 1, it can be seen that in Examples 1 to 3, the recovery rate of the carbon component is more than 90%, and the loss rate of the metal component is less than 4%. It is speculated that this is because by heating the powder sample at more than 850°C, most of the metal component is reduced to a state of a metal element, and by agglomerating the reduced metal component, the specific gravity is increased and the sedimentation property is improved. In addition, it is speculated that by implementing a separation process after the heating process, the separation of the metal component and the carbon component is improved, and even if the recovery rate of the carbon component is high, the loss rate of the metal component can be suppressed to a low level.

[0093] The above is a detailed description of the technology disclosed in this article, but these are only examples and do not limit the scope of protection claimed in the patent. The technology described in the scope of protection claimed in the patent includes various deformations and changes to the specific examples illustrated above. That is, the technology disclosed in this article includes the following items 1 to 6.

[0094] <Item 1> A method for processing battery components, comprising the following steps: a heating step; heating a recycling object at a temperature above 850°C, wherein the recycling object contains at least: a positive electrode comprising a lithium transition metal composite oxide having a layered structure, and a negative electrode comprising a carbon material; a separation step, adding a foaming agent and a collecting agent to a slurry containing the recycling object after the heating step, and separating the metal component and the carbon component contained in the recycling object.

[0095] <Item 2> The processing method according to Item 1, wherein 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, and further comprises a screening step before the separation step: screening the metal foil included in the recycling object.

[0096] <Item 3> The treatment method according to Item 1 or Item 2, wherein the lithium transition metal composite oxide having a layered structure contains at least Ni and Co.

[0097] <Item 4> The treatment method according to any one of Items 1 to 3, wherein the heating step is performed under an inactive environment.

[0098] <Item 5> A treatment method according to any one of Items 1 to 4, wherein the heating step includes a reducing component adding step: the reducing component is added in such a manner that the amount of the reducing component relative to the amount of the oxygen element contained in the recovery object becomes above a threshold value of the stoichiometric ratio based on the oxide of the reducing component.

[0099] <Item 6> The treatment method according to Item 5, wherein the reducing component is carbon, and the threshold value is a value greater than or equal to the stoichiometric ratio of CO 2 .

Claims

1. A method for processing battery components, comprising the following steps: A heating step of heating the recycling object at 850° C. or higher, wherein the recycling object at least comprises: a positive electrode comprising a lithium transition metal composite oxide having a layered structure, and a negative electrode comprising a carbon material; and The separation step is to add a foaming agent and a collecting agent to the slurry containing the recovery object after the heating step, so as to separate the metal component and the carbon component contained in the recovery object.

2. The processing method according to claim 1, wherein: 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 further includes, before the separation step, a screening step of screening the metal foil contained in the recycling object.

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

4. The processing method according to claim 1, wherein: The heating step is performed in an inert environment.

5. The processing method according to claim 1, wherein: The heating process comprises: The reducing component adding step adds the reducing component so that the amount of the reducing component relative to the amount of the oxygen element contained in the recovery object becomes equal to or greater than a threshold value of a stoichiometric ratio based on an oxide of the reducing component.

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

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