Manufacturing method of battery material

Abstract

According to the present disclosure, it is possible to improve the recovery efficiency of Li from a recovery target such as a used lithium ion secondary battery. The disclosed manufacturing method comprises: a preparation step (S11) for preparing an object to be recovered containing at least Li; and a chlorination heating step (S12) in which the object to be recovered is heated together with a non-metallic chlorine compound to produce LiCl. Since the LiCl is easily dissolved in water, Li can be easily separated from the object to be recovered. Namely, according to the technology disclosed herein, Li can be separated from the object to be recovered immediately after the chlorination heating step S12, and thus Li recovery efficiency can be greatly improved.

Description

Technical Field

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

[0002] Lithium-ion secondary batteries are widely used in various fields. The lithium-ion secondary batteries use various materials containing valuable metals such as Ni and Co. For example, lithium transition metal composite oxides such as lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, and lithium nickel cobalt manganese composite oxide are used as the positive electrode active material. In addition, aluminum is used as the positive electrode core. On the other hand, carbon materials are used as the negative electrode active material. Moreover, copper is used as the negative electrode core. Furthermore, aluminum is also used as the battery case that accommodates these electrodes.

[0003] In recent years, a recycling technology is being developed to recover valuable metals from used batteries, engineering end materials, etc. and reuse them as battery materials. In this recycling technology, first, the recycling object (used batteries, engineering end materials, etc.) is roasted. Then, the roasted recycling object is subjected to acid leaching. As a result, a metal solution in which the metal components (Li, Ni, Co, Mn, Al, Cu, etc.) in the recycling object are dissolved in the acid solution can be obtained. In addition, the carbon component in the recycling object can be separated by this acid leaching. On the other hand, various separation treatments (neutralization precipitation, solvent extraction, etc.) are applied to the metal solution after acid leaching. As a result, the desired metal component can be extracted and reused as a battery material.

[0004] An example of this recovery technology is disclosed in Patent Documents 1 and 2. For example, the treatment method described in Patent Document 1 includes: a leaching step, in which lithium-ion battery waste (recovery object) is leached with acid to obtain a leached solution containing at least fluoride ions and aluminum ions; a neutralization step, in which the leached solution is neutralized to a pH range of 5.3 to 5.5, and at least a portion of the aluminum ions are removed from the leached solution to obtain a neutralized solution; and an extraction step, in which the neutralized solution is subjected to solvent extraction to extract the remaining aluminum ions from the neutralized solution. Furthermore, in the treatment method described in Patent Document 1, a recovery step of recovering valuable metals (Ni, Co, Li) from the extraction residual solution after the extraction step is implemented.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-164971

[0008] Patent Document 2: Japanese Patent Application Publication No. 2020-105598 Summary of the invention

[0009] However, the above-mentioned conventional recovery technology has the problem of low recovery rate of lithium (Li). Specifically, in the prior art, the metal solution after neutralization acid seepage is used to remove Al. Next, the valuable metals (Ni, Co, Mn, etc.) other than Li are successively recovered by solvent extraction. Then, Li is recovered from the residual liquid after solvent extraction. That is, in the prior art, various separation treatments are performed before recovering Li. Therefore, in the prior art, since Li is removed by the separation treatment before recovering Li, it is difficult to achieve a high Li recovery rate.

[0010] In order to solve the above-mentioned problems, a method for producing a battery material having the following structure (hereinafter also simply referred to as a “production method”) is provided.

[0011] The method for producing a battery material disclosed herein includes: a preparation step of preparing a recycling object containing at least Li; and a chlorination heating step of heating the recycling object with a non-metallic chlorine compound to generate LiCl.

[0012] In the manufacturing method of the above-mentioned structure, a chlorination heating step of heating the recovery object in the presence of a non-metallic chlorine compound is implemented. As a result, Li in the recovery object is chlorinated to generate lithium chloride (LiCl). Since the LiCl is easily soluble in water, Li can be easily recovered from the recovery object. That is, according to the technology disclosed herein, Li can be directly separated from the recovery object immediately after the chlorination heating step, so it can contribute to a significant improvement in the recovery efficiency of Li. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a longitudinal cross-sectional view schematically showing the internal structure of a lithium-ion secondary battery.

[0014] Figure 2 It is schematically indicated Figure 1 A perspective view of an electrode body of a lithium-ion secondary battery shown.

[0015] Figure 3 This is a flowchart illustrating a method for producing a battery material according to one embodiment.

[0016] Figure 4 This is a flowchart illustrating in detail a calcination step in a production method according to one embodiment.

[0017] Explanation of symbols

[0018] 1Lithium-ion secondary battery

[0019] 10 Shell

[0020] 12 Positive terminal

[0021] 14 Negative terminal

[0022] 20 electrode body

[0023] 30 positive plate

[0024] 32 positive electrode core

[0025] 34 Positive electrode active material layer

[0026] 40 negative plate

[0027] 42 negative electrode core

[0028] 44 Negative electrode active material layer

[0029] 50 Isolators DETAILED DESCRIPTION

[0030] 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 implementing the technology disclosed herein can be grasped as design matters based on the prior art in the field by those skilled in the art. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the field.

[0031] 1. Recycling objects

[0032] The manufacturing method of the battery material of the present embodiment manufactures the battery material (typically the material of the positive electrode active material of the lithium ion secondary battery, the precursor of the positive electrode active material, the positive electrode active material) by recovering valuable metals such as lithium (Li) from the specified recycling object. As an example of the recycling object here, a used lithium ion secondary battery can be cited. The lithium ion secondary battery is described in detail 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.

[0033] like Figure 1 As shown, the lithium ion secondary battery 1 includes a case 10 , an electrode body 20 , and an electrolyte (not shown).

[0034] (1) Housing

[0035] The shell 10 is a box-shaped container. The inside of the shell 10 contains the electrode body 20 and the electrolyte. The shell 10 is made of a metal material with a certain strength (aluminum (Al) or the like). In addition, the shell 10 is equipped with a positive terminal 12 and a negative terminal 14. The positive terminal 12 and the negative terminal 14 are connected to the electrode body 20 inside the shell 10. Specifically, the positive terminal 12 is connected to the positive electrode plate 30 (see Figure 2) is connected. Aluminum (Al) or the like is used for the positive electrode terminal 12. On the other hand, the negative electrode terminal 14 is connected to the negative electrode plate 40 of the electrode body 20. Copper (Cu) or the like is used for the negative electrode terminal 14.

[0036] (2) Electrode body

[0037] 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 2 The electrode body 20 shown is a wound electrode body. The wound electrode body is made by stacking a positive electrode plate 30, a negative electrode plate 40, and a 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 may be other structures known in the past (laminated electrode body, etc.).

[0038] The positive electrode plate 30 includes a positive electrode core 32 as a conductive metal foil and a positive electrode active material layer 34 applied to the surface of the positive electrode core 32. The positive electrode core 32 uses aluminum (Al) or the like. In addition, the positive electrode active material layer 34 is a composite material layer containing a positive electrode active material, a conductive material, a binder, etc. The positive electrode active material is a metal material containing at least lithium (Li). As an example of the positive electrode active material, lithium transition metal composite oxides such as lithium nickel composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide, lithium nickel manganese composite oxide, lithium manganese cobalt composite oxide, lithium nickel cobalt composite oxide, and lithium nickel manganese cobalt composite oxide can be cited. In addition, as other examples of positive electrode active materials, lithium transition metal phosphorus oxides such as lithium iron phosphate, lithium manganese phosphate, and lithium manganese iron phosphate can be cited. According to the manufacturing method of this embodiment, Li can be efficiently recovered from the recovery object containing these positive electrode active materials. It should be noted that in the manufacturing method of this embodiment, other valuable metals such as Ni, Co, and Mn can also be efficiently recovered from the recovery object. Therefore, the positive electrode active material in the recycling object is particularly preferably a lithium transition metal composite oxide containing Ni, Co, and Mn. In addition, as the conductive material, carbon materials such as acetylene black and graphite can be cited. In addition, as the binder, resin materials such as polyvinylidene fluoride (PVdF) can be cited.

[0039] On the other hand, 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 applied to the surface of the negative electrode core 42. Copper (Cu) or the like is used for the negative electrode core 42. In addition, the negative electrode active material layer 44 is a composite layer containing a negative electrode active material, a binder, a thickener, and the like. As an example of a negative electrode active material, carbon materials such as graphite, hard carbon, and soft carbon can be cited. In addition, as other examples of negative electrode active materials, lithium titanate (LTO), silicon carbide (SiC), a composite containing carbon and silicon, silicon oxide (SiO X) etc. In addition, as the binder, resin materials such as styrene butadiene rubber (SBR) can be mentioned. As the thickener, resin materials such as carboxymethyl cellulose (CMC) can be mentioned.

[0040] In addition, the separator 50 is an insulating sheet 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.

[0041] (3) Electrolytes

[0042] The electrolyte is present between the positive electrode plate 30 and the negative electrode plate 40. Thus, the charge carrier (Li ion) can be moved 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 is not limited to the technology disclosed herein.

[0043] As an example of a recycling object in the manufacturing method of the present embodiment, a lithium-ion secondary battery 1 is described above. However, the manufacturing 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 a lithium-ion secondary battery, a portion of the positive electrode plate is sometimes cut off when an electrode body is manufactured. The portion of the cut positive electrode plate (engineering end material) also contains Li, and therefore can become a recycling object of the manufacturing method disclosed herein. In addition, at the manufacturing site of a lithium-ion secondary battery, sometimes the electrode body after manufacture has some defects and cannot be used in products. Such an electrode body also contains Li, and therefore can become a recycling object. That is, the recycling object of the manufacturing method disclosed herein only needs to contain at least Li, and is not particularly limited to a specific structure.

[0044] 2. Manufacturing methods of battery materials

[0045] Hereinafter, a method for producing the battery material according to the present embodiment will be described. Figure 3 It is a flowchart explaining the manufacturing method of this embodiment. Figure 4 It is a detailed description Figure 3 Flow chart of the roasting process in .

[0046] like Figure 3As shown, the manufacturing method of the battery material of this embodiment includes a calcination step S10, a water dissolution step S20, a Mn crystallization step S30, a Li crystallization step S40, a sorting step S50, an NH3 seepage step S60, a solvent extraction step S70, an NC crystallization step S80, and an active material generation step S90. Each step will be described below.

[0047] (1) Calcination step S10

[0048] In this process, the recycling object is heated at a predetermined temperature. Thus, the liquid components (electrolyte, etc.) in the recycling object can be removed, and the resin components (adhesive, separator, etc.) can be carbonized. In addition, when the charged lithium ion secondary battery 1 is used as the recycling object, the function as a battery can be stopped by performing the roasting process S10. Thus, the subsequent processes can be safely performed.

[0049] Here, if Figure 4 As shown, the calcination step S10 in the present embodiment includes a preparation step S11 and a chlorination heating step S12. This can significantly improve the recovery efficiency of Li. This will be described in detail below.

[0050] (a) Preparation Step S11

[0051] In this process, a recycling object containing at least Li is prepared. As described above, the "recycling object" in the technology disclosed herein is not limited to a finished lithium-ion secondary battery, and includes engineering end materials, defective parts (electrode bodies, etc.). It should be noted that since the details of the recycling object have been described, repeated descriptions are omitted. It should be noted that according to the manufacturing method of this embodiment, in addition to the above-mentioned lithium (Li), nickel (Ni), cobalt (Co), manganese (Mn), etc. can also be recovered (manufactured).

[0052] (b) Chlorination Heating Step S12

[0053] In the chlorination heating step S12, the recovery object is heated together with the non-metallic chlorine compound. As a result, Li in the recovery object reacts with Cl in the non-metallic chlorine compound to generate lithium chloride (LiCl). In addition, when Mn is contained in the recovery object, the Mn can also react with Cl to generate manganese chloride (MnCl2). On the other hand, in this step, since Li and Mn are preferentially chlorinated, the metal elements (Ni, Co, Al, Cu) are hardly chlorinated.

[0054] It should be noted that the "non-metallic chlorine compound" in this specification refers to a chlorine compound that does not contain a metal element. The non-metallic chlorine compound is not particularly limited as long as it is a compound that can be decomposed during heating and supply Cl to the Li in the recovery object, and a previously known compound can be appropriately selected. As an example of the non-metallic chlorine compound, inorganic chlorine compounds such as hydrogen chloride (HCl), ammonium chloride (NH4Cl), perammonium chloride (NH4ClO4), perchloric acid (HClO4), chloric acid (HClO3), chlorous acid (HClO2), and hypochlorous acid (HClO) can be cited. In addition, as other examples of non-metallic chlorine compounds, organic chlorine compounds such as methyl chloride, dichloromethane, trichloromethane (chloroform), and tetrachloroethylene can be cited. These non-metallic chlorine compounds can supply Cl without mixing other metal elements that may become impurities into the recovery object.

[0055] In addition, as long as Cl can be properly supplied to the recovery object, the state of the non-metallic chlorine compound is not particularly limited. For example, when the non-metallic chlorine compound is a gas, the non-metallic chlorine compound can be mixed into the heating gas described later and supplied to the heating furnace. In addition, when the non-metallic chlorine compound is a liquid or a solid, the mixture formed by mixing the recovery object and the non-metallic chlorine compound can be heated. In either case, Cl in the non-metallic chlorine compound can be properly supplied to the recovery object.

[0056] It should be noted that the heating temperature in this process can be 500°C or more, can be 525°C or more, can be 550°C or more, can be 575°C or more. There is a tendency to easily generate LiCl as the heating temperature increases. In particular, the heating temperature is preferably 600°C or more, more preferably 800°C or more, and particularly preferably 900°C or more. Thus, the Li recovery rate is particularly significantly improved. On the other hand, from the viewpoint of the generation of LiCl, the upper limit of the heating temperature is not particularly limited, and can be 1500°C or less, can be 1400°C or less, and can be 1300°C or less. It should be noted that, considering the reduction in the cost required for the heat treatment, the upper limit of the heating temperature is preferably 1200°C or less, more preferably 1100°C or less, and particularly preferably 1000°C or less.

[0057] In addition, although it is not an element of the technology disclosed herein, in this process, it is preferred to heat the recovery object under an inert atmosphere. Thus, the generation of metal oxides (lithium oxide (Li2O), etc.) can be suppressed and the chlorination selectivity can be improved. As a specific example of the inert gas at this time, inert gases such as argon and nitrogen can be cited. It should be noted that the "inert atmosphere" in this specification refers to a heating atmosphere containing the above-mentioned inert gas as a main component. In other words, the "inert atmosphere" in this specification is not limited to a completely inert atmosphere in which the content of the inert gas is 100% (the content of the oxygen element is 0%), and may also contain a very small amount of oxygen element. Specifically, the heating atmosphere in this process only needs to have an oxygen content of 5% or less (preferably 3% or less, more preferably 1% or less, further preferably 0.5% or less, and particularly preferably 0.1% or less). However, in the case where the recovery object contains sufficient reducing components (carbon (C), etc.), even if an oxygen element exceeding the above range is mixed, LiCl can be appropriately generated.

[0058] In addition, in this process, it is preferred to set a water trap that allows the used heating gas (exhaust gas discharged from the heating furnace) to pass through water. Thus, the LiCl in the exhaust gas can be captured by the water trap, so the recovery rate of Li can be further improved. It should be noted that the water after the exhaust gas passes can be mixed with the Li solution prepared in the water dissolution step S20 described later. Thus, Li can be efficiently recovered.

[0059] (2) Water dissolution step S20

[0060] Next, in the water dissolution step S20, the recovery object after the chlorination heating step S12 is mixed with water. As described above, the recovery object after the chlorination heating step S12 contains LiCl. This LiCl is easily dissolved in water such as pure water and ion exchange water. As a result, in this step, a Li solution in which LiCl is dissolved in water can be obtained. In this way, in the manufacturing method of this embodiment, Li can be easily separated from the recovery object immediately after the chlorination heating step S12. As a result, a Li solution containing high-purity Li can be obtained.

[0061] It should be noted that the immersion time in this process is preferably more than 10 minutes, preferably more than 15 minutes, preferably more than 20 minutes, and particularly preferably more than 25 minutes. Thus, the LiCl in the recovery object can be fully dissolved in water. In addition, if the immersion time exceeds 30 minutes, the LiCl in the recovery object can be almost completely dissolved in water. Therefore, considering the manufacturing efficiency, the upper limit of the immersion time is preferably less than 120 minutes, preferably less than 90 minutes, preferably less than 60 minutes, and particularly preferably less than 45 minutes. In addition, the temperature of the water in this process is not particularly limited and can be appropriately set within the range of 10°C to 60°C.

[0062] (3) Mn precipitation step S30

[0063] It should be noted that when the recovery object includes Mn, MnCl2 is sometimes generated in the chlorination heating step S12. Since the MnCl2 is also soluble in water, the Li solution after the water dissolution step S20 contains Mn. In this step, the Mn is recovered from the Li solution. For example, in this step, an aqueous sodium hydroxide solution is added to the Li solution. As a result, manganese hydroxide (Mn(OH)2) is precipitated from the Li solution. Then, Mn can be recovered by filtering the Li solution.

[0064] (4) Li precipitation step S40

[0065] In this process, crystals of Li compounds are precipitated from the Li solution. In this process, a previously known crystallization process can be adopted without particular limitation. For example, in this process, sodium carbonate can be added to the Li solution. Thus, crystals of lithium carbonate (Li2CO3) can be precipitated from the Li solution. It should be noted that the Li compound generated in this process is not limited to lithium carbonate. For example, lithium hydroxide (LiOH) can be generated as a Li compound as needed. In the generation of the lithium hydroxide, first, the lithium carbonate precipitated from the metal solution is dissolved (or suspended) in a prescribed solvent. Then, calcium hydroxide is added to the solution. Then, the solvent is evaporated and removed as needed. Thus, crystals of lithium hydroxide can be precipitated.

[0066] As described above, in the manufacturing method of this embodiment, Li can be recovered from the metal solution (Li solution) generated after the roasting step S10. That is, according to the manufacturing method of this embodiment, the number of steps from the completion of the roasting step S10 to the recovery of Li can be greatly reduced. As a result, a high Li recovery rate can be achieved.

[0067] (5) Sorting process S50

[0068] On the other hand, the unchlorinated metal elements (Ni, Co, Al, Cu, etc.) in the roasting step S10 remain in the solid content (recycling object) after the water dissolution step S20. In the case where other valuable metals (Ni, Co) are included in the residual metal, it is preferred to recycle these valuable metals. In contrast, in the manufacturing method of the present embodiment, the solid content after the water dissolution step S20 is subjected to a sorting step S50. In this step, the various components contained in the recycling object after the water dissolution step S20 are sorted by a sieve. For example, in the case where the engineering end material of the positive electrode plate 30 is the recycling object, the positive electrode core 32 can be sorted from the engineering end material with a sieve and removed from the recycling object. In addition, in the case where the electrode body 20 is the recycling object, in addition to the positive electrode core 32, the negative electrode plate 40 can also be removed from the recycling object. Furthermore, in the case where the lithium-ion secondary battery 1 is the recycling object, in addition to the above-mentioned positive electrode core 32 and negative electrode plate 40, the shell 10 can also be removed from the recycling object. As a result, the content of impurities (Al, Cu, etc.) in the recovery object is reduced, so it can contribute to the improvement of the recovery efficiency of valuable metals (Co, Ni). It should be noted that, as in the present embodiment, the sorting process is preferably implemented after the water dissolution process. As a result, LiCl attached to the removal object (positive electrode core, negative electrode plate, shell, etc.) in the sorting process can be recovered first.

[0069] It should be noted that in this process, the recycling object can be crushed as needed. This can improve the efficiency of sorting each component. For example, when the lithium-ion secondary battery 1 is the recycling object, the shell 10 and the electrode body 20 can be crushed. This makes it easy to remove the shell 10, the positive electrode core 32 and the negative electrode plate 40 from the recycling object.

[0070] In addition, the sorting process S50 is not intended to completely remove impurities such as Al and Cu from the recycling object. The details will be described later. Even if impurities remain in the recycling object, they can be fully removed in the subsequent processes (NH3 seepage process S60, solvent extraction process S70, etc.). That is, this process can also be appropriately omitted as needed. For example, in the case of a recycling object with a low impurity content (such as the engineering end material of the positive plate 30), even if this process is omitted, valuable metals can be efficiently recovered.

[0071] (6) NH3 seepage step S60

[0072] In this process, the solid component after the water dissolution process S20 (for example, after the sorting process S50) is immersed in an ammonia solution. As a result, Ni, Co, Cu and the like among the metal elements (Ni, Co, Al, Cu) in the solid component are dissolved in the ammonia solution. As a result, a metal solution containing Ni, Co, and Cu can be obtained. On the other hand, Al, which is not easily dissolved in the ammonia solution, remains in the solid component. As a result, Al as an impurity can be easily removed.

[0073] (7) Solvent extraction step S70

[0074] In this process, Co and Ni are extracted from the metal solution by solvent extraction. Thus, a Co solution and a Ni solution can be obtained respectively. In addition, in this process, impurities (Al, Cu, etc.) mixed in the metal solution can also be separated. Specifically, the solvent extraction process S70 in this embodiment includes a Co extraction process and a Ni extraction process. The following is a specific description.

[0075] (a) Co extraction process

[0076] In this step, an organic solvent (first extracting liquid) having high extractability for Co and low extractability for Ni, Al, and Cu is added to the metal solution. Thus, Co can be separated from the metal solution, and a Co solution in which Co is dissolved in the first extracting liquid can be obtained. Specific examples of the first extracting liquid include phosphonic acid esters such as 2-ethylhexylphosphonate (PC-88A).

[0077] In addition, in this process, the extracted Co solution (the first extract containing Co) can be subjected to a stripping treatment. In the stripping treatment, first, the Co solution (organic phase) and the acidic aqueous solution are stirred and mixed using a mixer or the like. Then, the mixture is allowed to stand until the two liquids are separated. Thus, an aqueous Co solution in which Co is dissolved in the acidic aqueous solution can be obtained. It should be noted that as the acidic aqueous solution used in the stripping treatment, sulfuric acid, hydrochloric acid, etc. (particularly sulfuric acid) can be cited.

[0078] (b) Ni extraction process

[0079] In this process, an organic solvent (second extract) with high Ni extraction performance and low Al and Cu extraction performance is added to the metal solution. Thus, Ni can be separated from the metal solution, and a Ni solution in which Ni is dissolved in the second extract can be obtained. It should be noted that as specific examples of the second extract, carboxylic acid extractants such as neodecanoic acid and cyclohexane acid can be cited. In addition, the extracted Ni solution (second extract containing Ni) can also be subjected to a back extraction treatment. Thus, an aqueous Ni solution can be obtained. It should be noted that since the steps of the back extraction treatment have been described, repeated records are omitted.

[0080] (8) NC crystallization step S80

[0081] In this process, crystals of metal compounds containing Ni and Co are precipitated. In this process, the crystallization treatment known in the past can be adopted without particular limitation. For example, in the case where the stripping treatment is respectively implemented in the Co extraction process and the Ni extraction process, a mixed solution of an aqueous system mixed with a Co solution and a Ni solution is prepared. Thus, a mixed solution containing Ni and Co can be obtained. Then, the pH of the mixed solution is controlled to be alkaline. Thus, crystals of metal compounds can be precipitated. It should be noted that in the preparation of the mixed solution, the mixing ratio of Ni and Co can be changed as needed. Then, in the adjustment of pH, the mixed solution is added dropwise to the reaction tank together with an alkaline solution (ammonia water, sodium hydroxide aqueous solution). Thus, NiCo hydroxide can be crystallized.

[0082] (9) Active Material Generation Step S90

[0083] In this process, the Li compound, Mn compound and NiCo compound obtained in the above steps are used to generate battery materials (positive electrode active materials). Specifically, first, NiCo compound (NiCo hydroxide), Mn compound (Mn (OH) 2) and Li compound (Li2CO3, etc.) are mixed in a predetermined ratio. Then, the mixture is calcined. Thus, the positive electrode active material (lithium transition metal composite oxide) of the lithium ion secondary battery can be manufactured.

[0084] The above is a description of the manufacturing method of the battery material of the present embodiment. As described above, in the roasting step S10 of the manufacturing method of the present embodiment, a chlorination heating step S12 of heating the recovery object in an environment where a non-metallic chlorine compound is present is implemented. As a result, the Li in the recovery object is chlorinated to generate lithium chloride (LiCl). Since the LiCl is easily soluble in water, Li can be easily recovered from the recovery object. That is, according to the technology disclosed herein, Li can be directly separated from the recovery object immediately after the roasting step S10. As a result, the number of steps from the completion of the roasting step S10 to the recovery of Li can be greatly reduced, and a high Li recovery rate can be achieved.

[0085] 3. Other Implementation Methods

[0086] An embodiment of the technology disclosed herein has been described above. It should be noted that the technology disclosed herein is not limited to the above embodiment, and includes other embodiments in which various configurations are changed. Other examples of the embodiments of the technology disclosed herein will be described below.

[0087] In the manufacturing method of the above embodiment, after the roasting step S10 is implemented, the sorting step S50 to the active material generation step S90 are implemented. However, the description of the above embodiment is not intended to limit the steps after the roasting step. That is, in the manufacturing method disclosed herein, the steps after the roasting step can be appropriately added, deleted, or changed as needed.

[0088] (1) Omission of Mn precipitation process

[0089] For example, in the manufacturing method of the above embodiment, since the Li solution after the water dissolution step S20 contains Mn, the Mn precipitation step S40 is implemented before the Li precipitation step S40 is implemented. However, when the recovery object does not contain Mn, a Li solution containing only Li can be obtained in the water dissolution step S20. In this case, the Mn precipitation step S30 can be omitted.

[0090] (2) Omission of steps after the NH3 seepage step

[0091] In addition, in the manufacturing method of the above embodiment, valuable metals such as Ni and Co are recovered by implementing the NH3 seepage step S60 to the NCM crystallization step S80. However, when the recovery object does not contain Ni and Co, the steps after the NH3 seepage step can also be omitted. In addition, the steps after the NH3 seepage step can also be appropriately changed according to the type of metal elements contained in the recovery object.

[0092] (3) Changes in the solvent extraction process

[0093] In addition, the specific processing steps in the solvent extraction process S70 can be appropriately changed. For example, the solvent extraction process S70 in the above embodiment includes a Co extraction process and a Ni extraction process. Thus, the Co solution and the Ni solution can be extracted separately. However, in the solvent extraction process S70, Ni and Co can also be extracted simultaneously. Specifically, an organic solvent with high extractability for Ni and Co and low extractability for Al and Cu can be added to the metal solution. If Ni and Co are extracted simultaneously in this way, it is possible to improve manufacturing efficiency by shortening the process.

[0094] (4) Omission of solvent extraction process

[0095] In addition, in the manufacturing method of the above-mentioned embodiment, a lithium-ion secondary battery is used as a recycling object. Such a recycling object contains Cu from the negative electrode core, etc. Therefore, in addition to Ni and Co, Cu is also mixed in the metal solution generated in the NH3 seepage step S60. In this case, as in the above-mentioned embodiment, it is preferred to implement a solvent extraction step S70 to remove Cu from the metal solution. On the other hand, when a recycling object that does not contain Cu (engineering end materials of positive plates, etc.) is used, Cu is not mixed in the metal solution generated in the NH3 seepage step S60. In this case, the solvent extraction step S70 can also be omitted, and the NC crystallization step S80 can be implemented on the metal solution obtained in the NH3 seepage step S60.

[0096] (5) Addition of Li separation step

[0097] In addition, the Li separation process may also be performed on the Li solution before the Li precipitation process S40 is implemented. Specifically, the Li solution contains Li as a main component. However, the Li solution may contain other metal components (Cu, Al, etc.). The Li separation process is a process for removing impurities from the Li solution. Thus, a high-purity Li compound can be obtained in the Li crystallization process S40. It should be noted that the method for preparing the Li solution is not particularly limited, and it is preferred to appropriately adopt a solvent extraction method, an ion exchange method, or other previously known methods.

[0098] (6) Addition of Li Concentration Process

[0099] In addition, the Li concentration process may be performed on the Li solution after the above-mentioned Li separation process. In the Li concentration process, the Li solution is heated to evaporate the solvent. As a result, a high-concentration Li solution can be obtained, thereby improving the crystallization efficiency in the Li crystallization process S40. It should be noted that the Li concentration process may also be performed on a metal solution that has not undergone the Li separation process. For example, when impurities are fully removed in the water dissolution process S20 and the Mn precipitation process S30, the Li separation process may not be performed and only the Li concentration process may be performed. In this case, a high-concentration Li solution can also be obtained.

[0100] (7) Changes in NC crystallization process

[0101] In addition, in the above-mentioned embodiment, the NC crystallization step S80 is implemented on the mixed solution containing Ni and Co. Thus, a metal compound (NiCo hydroxide) containing Ni and Co can be crystallized. However, the metal compound can also be crystallized separately from each of the Co solution and the Ni solution. For example, in the case of back extraction with sulfuric acid as in the above-mentioned embodiment, the solvent is removed and cooled as needed, thereby crystals of cobalt sulfate (CoSO4) can be precipitated from the Co solution. In addition, crystals of nickel sulfate (NiSO4) are precipitated from the Ni solution. By calcining the NC crystallized product synthesized from the crystals of these sulfates together with the Li compound and the Mn compound, a battery material (positive electrode active material) can be generated.

[0102] In addition, in the above-mentioned embodiment, NiCo hydroxide is crystallized from a mixed solution containing Ni and Co. However, a metal compound (NiCoMn hydroxide) containing Ni, Co and Mn can also be generated as a precursor of a positive electrode active material. Specifically, manganese hydroxide (Mn(OH)2) obtained in the Mn precipitation step S30 is added to a mixed solution containing Ni and Co. Thus, a mixed solution containing Ni, Co and Mn can be obtained. Then, by subjecting the mixed solution to a crystallization treatment, a metal compound (NiCoMn hydroxide) containing Ni, Co and Mn can be generated. By calcining the NiCoMn hydroxide together with a Li compound, a positive electrode active material can be generated.

[0103] [Test example]

[0104] Hereinafter, test examples related to the technology disclosed herein will be described. It should be noted that the contents of the test examples described below are not intended to limit the technology disclosed herein.

[0105] 1. First Test

[0106] In this experiment, the positive electrode plate was used as the recycling object, and the recycling object was subjected to a roasting process. Specifically, as the positive electrode plate, a positive electrode plate with a positive electrode active material layer coated on the surface of the positive electrode core (Al foil) was used. It should be noted that the positive electrode active material in this experiment used lithium nickel cobalt manganese composite oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2). Then, the positive electrode plate was cut into a sheet of 2 cm×4 cm to prepare a test sample.

[0107] Next, in this test, the test sample is heated together with the non-metallic chlorine compound. Specifically, the test sample is placed in a crucible and stored in an electric furnace. Then, a mixed gas of HCl gas and Ar gas is supplied, and the temperature in the furnace is raised to 600°C. In addition, a water collector is arranged in the exhaust pipe of the electric furnace to pass the heated exhaust gas through water. It should be noted that the heating rate in this process is set to 5°C / min. In addition, the supply amount of the mixed gas is set to 4.2L / min. Then, the furnace temperature is maintained at 600°C, and roasting is performed for 1 hour. Then, the test sample is recovered after the furnace temperature is cooled to 50°C. It should be noted that the mixed gas is continuously supplied to the furnace before the sample is recovered.

[0108] Next, in this test, the calcined test sample was immersed in water for 30 minutes, and then the water was filtered to obtain a Li solution. Then, water recovered from the water collector of the electric furnace was added to the Li solution. Next, a 30wt% NaOH aqueous solution was added dropwise until the pH of the Li solution reached 11. Then, Mn was removed from the Li solution by recovering the precipitate (Mn(OH)2). Next, a 10wt% Na2CO3 aqueous solution was added to the Li solution to precipitate lithium carbonate (Li2CO3). Then, all the precipitated Li2CO3 was collected and the amount of Li substance was determined by ICP. Then, the recovery rate of Li was calculated based on the following formula (1). It should be noted that the "amount of Li substance before calcination" in formula (1) is the amount of Li substance obtained by ICP analysis of a reference sample cut from the positive plate.

[0109] Li recovery rate = (amount of Li substance in precipitated Li2CO3 / amount of Li substance in the positive electrode plate before calcination) × 100 (1)

[0110] The results of the above test surprisingly confirmed a very high Li recovery rate of more than 90%. Although the details are omitted, it is confirmed that when Li is recovered from the residual liquid after neutralization precipitation and solvent extraction as in Patent Document 1, the Li recovery rate is about 20 to 60%. It can be seen that by heating the recovery object with a non-metallic chlorine compound in the roasting process to generate LiCl, it can help to significantly improve the recovery efficiency of Li. This is understood to be because multiple separation steps as in the prior art can be omitted, and Li can be directly separated from the recovery object immediately after the roasting process.

[0111] 2. Second Test

[0112] In the second test, the Li recovery rates of two samples with different heating temperatures in the chlorination heating step were measured. In addition, in this test, the recovery rates of metals other than Li were also measured. This will be described in detail below.

[0113] 1. Sample Preparation

[0114] (1) Sample 1

[0115] In sample 1, a Li solution was obtained under the same conditions as in the first test. That is, in sample 1, the positive electrode plate was calcined at 600°C together with a non-metallic chlorine compound (HCl gas). Then, the Li solution was obtained by immersing the calcined positive electrode plate in water for 30 minutes. In addition, in this test, water recovered from the water collector of the electric furnace was also added to the Li solution.

[0116] (2) Sample 2

[0117] In Sample 2, a Li solution was obtained under the same conditions as Sample 1 (first test) except that the heating temperature was changed to 927°C.

[0118] 2. Evaluation test

[0119] In this experiment, ICP was used to analyze the elements contained in the Li solution of each sample. Specifically, without pretreatment to separate specific elements, ICP analysis of Li, Ni, Co, Mn and Al was performed on the water (Li solution) impregnated with the test samples. Then, the water leaching rate of each of the above elements was calculated based on the measurement results. The water leaching rate is calculated based on the following formula (2). It should be noted that, as with the above formula (1), the "atomic weight before calcination" is the atomic weight obtained by ICP analysis of a reference sample cut from the positive plate. The water leaching amount of each element of samples 1 and 2 is shown in Table 1.

[0120] Water leaching rate = (atomic weight in Li solution / atomic weight in positive electrode plate before calcination) × 100 (2)

[0121] [Table 1]

[0122]

[0123] As shown in Table 1, high Li recovery rates of 90% or more were confirmed in both samples 1 and 2. On the other hand, when comparing sample 1 and sample 2, the Li recovery rate of sample 2 was higher. It can be seen that the heating temperature in the chlorination heating step is preferably 900°C or more. In addition, it was confirmed that the Li solution after water leaching mainly contained Li and Mn, and almost did not contain Ni, Co, and Al.

[0124] The above detailed description of the technology disclosed herein is for illustration only and does not limit the scope of the patent claims. The technology described in the scope of the patent claims includes various deformations and changes to the specific examples illustrated above. That is, the technology disclosed herein includes the forms described in the following items 1 to 8.

[0125] <Project 1>

[0126] A method for manufacturing a battery material, comprising:

[0127] a preparation step of preparing a recycling object including at least Li; and

[0128] In the chlorination heating step, the above-mentioned recovery object is heated together with a non-metallic chlorine compound to generate LiCl.

[0129] <Project 2>

[0130] According to the method for manufacturing a battery material as described in item 1, the non-metallic chlorine compound comprises at least one selected from hydrogen chloride, ammonium chloride, ammonium perchloride, perchloric acid, chloric acid, hypochlorous acid, methyl chloride, dichloromethane, chloroform, and tetrachloroethylene.

[0131] <Project 3>

[0132] The method for producing a battery material according to item 1 or 2, wherein the chlorination heating step heats the recycling object at 500°C to 1000°C.

[0133] <Item 4>

[0134] The method for producing a battery material according to any one of items 1 to 3, wherein the chlorination heating step heats the recycling target in an inert atmosphere.

[0135] <Item 5>

[0136] A method for manufacturing a battery material according to any one of items 1 to 4, wherein the recycling object comprises at least one selected from lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel manganese composite oxide, lithium manganese cobalt composite oxide, lithium nickel cobalt composite oxide, lithium nickel manganese cobalt composite oxide, lithium iron phosphate, lithium manganese phosphate, and lithium manganese iron phosphate.

[0137] <Item 6>

[0138] The method for producing a battery material according to any one of items 1 to 5, further comprising a water dissolution step of immersing the recovered object after the chlorination heating step in water to obtain a Li solution in which the LiCl is dissolved in the water.

[0139] <Item 7>

[0140] The method for manufacturing the battery material according to item 6, further comprising:

[0141] In the Li precipitation step, crystals of a Li compound are precipitated from the Li solution.

[0142] <Item 8>

[0143] According to the manufacturing method of battery materials described in Item 6 or 7, wherein the above-mentioned recycling object contains at least one of Ni and Co, the manufacturing method of the above-mentioned battery material further comprises: an NH3 seepage process, immersing the solid material after the above-mentioned water dissolution process in an ammonia solution to obtain a metal solution containing at least one of the above-mentioned Ni and the above-mentioned Co.

[0144] <Item 9>

[0145] The method for producing a battery material according to item 3, wherein the chlorination heating step heats the recycling object at 900° C. or higher.

Claims

1. A method for manufacturing a battery material, comprising: A preparation step of preparing a recycling object including at least Li; as well as In the chlorination heating step, the recovery object is heated together with a non-metallic chlorine compound to generate LiCl.

2. The method for producing a battery material according to claim 1, wherein: The non-metallic chlorine compound comprises at least one selected from hydrogen chloride, ammonium chloride, ammonium perchloride, perchloric acid, chloric acid, hypochlorous acid, methyl chloride, dichloromethane, chloroform, and tetrachloroethylene.

3. The method for producing a battery material according to claim 1, wherein: The chlorination heating step heats the recycling object at 500°C to 1000°C.

4. The method for producing a battery material according to claim 1, wherein: The chlorination heating step heats the recovery object in an inert atmosphere.

5. The method for producing a battery material according to claim 1, wherein: The recycling object includes at least one selected from lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel manganese composite oxide, lithium manganese cobalt composite oxide, lithium nickel cobalt composite oxide, lithium nickel manganese cobalt composite oxide, lithium iron phosphate, lithium manganese phosphate, and lithium manganese iron phosphate.

6. The method for producing a battery material according to any one of claims 1 to 5, wherein: Further including: The water dissolution step is to immerse the recovery object after the chlorination heating step in water to obtain a Li solution in which the LiCl is dissolved in the water.

7. The method for producing a battery material according to claim 6, wherein: Further including: The Li precipitation step is to precipitate crystals of a Li compound from the Li solution.

8. The method for producing a battery material according to claim 6, wherein: The recycling object contains at least one of Ni and Co, and the manufacturing method of the battery material further includes: an NH3 seepage process, immersing the solid material after the water dissolution process in an ammonia solution to obtain a metal solution containing at least one of the Ni and the Co.

9. The method for producing a battery material according to claim 3, wherein: The chlorination heating step heats the recycling object at 900° C. or higher.

Images