Manufacturing method of battery material

Abstract

According to the present disclosure, Li can be recovered with low energy from a recovery target such as a used lithium ion secondary battery. The manufacturing method disclosed herein includes: a preparation step of preparing a recovery target containing lithium and a first metal element; a chlorination heating step in which the object to be recovered is heated together with a metal chloride to generate LiCl; and a water dissolution step in which the object to be recovered after the chlorination heating step is immersed in water to obtain a Li solution in which LiCl is dissolved in water. Furthermore, in the production method disclosed herein, the heating temperature in the chlorination heating step is 1000 DEG C or less, and the metal chloride contains a second metal element that is more easily chlorinated than the first metal element in the recovery target in the chlorination heating step and is less susceptible to chlorination than the lithium. As a result, Li can be easily recovered from the object to be recovered at a low energy of 1000 DEG C or less.

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, considering the impact on the environment, a recycling technology is being developed to recover valuable metals from used batteries, engineering end materials, etc. and reuse them as battery materials. An example of this recycling technology is disclosed in Patent Document 1. In the recycling technology described in Patent Document 1, lithium-containing materials such as lithium batteries are melted in a metal molten bath furnace. At this time, in the technology described in Patent Document 1, alkali metal chlorides and alkaline earth metal chlorides are added to the molten bath furnace. As a result, aerosolized (microparticleized after evaporation) LiCl is generated. It is said that lithium can be recovered from lithium-containing materials in this way.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-507413 Summary of the invention

[0007] However, in the recycling technology described in Patent Document 1, the recycling object (lithium battery, etc.) and metal chloride (metal chloride) are melted and evaporated to generate aerosolized LiCl. Therefore, the temperature of the heat treatment needs to be set to a high temperature of 1500° C. or higher. That is, the technology described in Patent Document 1 uses a large amount of energy to recover Li, so it is difficult to say that the impact on the environment is fully considered.

[0008] 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.

[0009] The manufacturing method of the battery material disclosed herein includes: a preparation step of preparing a recycling object including lithium and a first metal element; a chlorination heating step of heating the recycling object together with a metal chloride to generate LiCl; and a water dissolution step of immersing the recycling object after the chlorination heating step in water to obtain a Li solution in which LiCl is dissolved in water. Moreover, in the manufacturing method disclosed herein, the heating temperature in the chlorination heating step is below 1000°C, and the metal chloride includes a second metal element that is easier to chlorinate than the first metal element in the recycling object and less likely to chlorinate than lithium in the chlorination heating step.

[0010] In the manufacturing method of the above-mentioned structure, a chlorination heating process is implemented to heat the recovery object together with the metal chloride. Moreover, the metal chloride used in the technology disclosed herein contains a second metal element that is easier to chlorinate than the first metal element (metal element other than Li) in the recovery object and less likely to chlorinate than Li. When heating a metal chloride containing such a second metal element, it is possible to selectively chlorinate Li without chlorinating other metal elements (first metal element) in the recovery object. Thus, lithium chloride (LiCl) can be efficiently generated even by heating at a low temperature below 1000°C. Moreover, since this LiCl is easily soluble in water, it can be easily separated from the recovery object by implementing a water dissolution process. That is, according to the manufacturing method disclosed herein, Li can be easily recovered with low energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a longitudinal cross-sectional view schematically showing the internal structure of a lithium-ion secondary battery.

[0012] Figure 2 It is schematically indicated Figure 1 A perspective view of an electrode body of a lithium-ion secondary battery shown.

[0013] Figure 3 This is a flowchart illustrating a method for producing a battery material according to one embodiment.

[0014] Figure 4 This is a flowchart illustrating in detail a calcination step in a production method according to one embodiment.

[0015] Figure 5 This is a flowchart illustrating in detail the solvent extraction step in the production method according to one embodiment.

[0016] Figure 6 This is data showing an example of thermodynamic equilibrium in the chlorination heating step.

[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. As described above, the recycling object (lithium-ion secondary battery 1) contains various metal elements other than lithium (Li). Here, in this specification, the metal element other than Li in the recycling object is referred to as the "first metal element". For example, when the lithium-ion secondary battery 1 is the recycling object, the first metal element includes Ni, Co, Mn, Al, Cu, Fe, etc. According to the technology disclosed herein, Li can be appropriately recovered from the recycling object containing such various metal elements.

[0044] It should be noted that the recycling object in the manufacturing method disclosed herein is not limited to the lithium-ion secondary battery 1 of the above-mentioned structure. For example, at the manufacturing site of the lithium-ion secondary battery, a part of the positive electrode plate is sometimes cut off when the electrode body is manufactured. The part of the positive electrode plate that is cut off (engineering end material) also contains Li, so it can become the recycling object of the manufacturing method disclosed herein. In addition, at the manufacturing site of the lithium-ion secondary battery, sometimes the electrode body after manufacture has some defects and cannot be used in the product. Such an electrode body also contains Li, so it 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.

[0045] 2. Manufacturing methods of battery materials

[0046] 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 . Figure 5 It is a detailed description Figure 3 Flowchart of the solvent extraction process.

[0047] like Figure 3 As shown, the manufacturing method of the battery material of this embodiment includes a calcination step S10, a water dissolution step S20, a Li crystallization step S30, a sorting step S40, an acid leaching step S50, a neutralization precipitation step S60, a solvent extraction step S70, an NCM crystallization step S80 and an active material generation step S90. Each step will be described below.

[0048] (1) Calcination step S10

[0049] 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.

[0050] Here, if Figure 4 As shown, the calcination step S10 in this embodiment includes a preparation step S12 and a chlorination heating step S14. This can significantly improve the recovery efficiency of Li. This will be described in detail below.

[0051] (a) Preparation Step S12

[0052] In this process, a recycling object including lithium and a first metal element 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).

[0053] (b) Chlorination Heating Step S14

[0054] In the chlorination heating step S14, the recovery object is heated together with the metal chloride. In the chlorination heating step S14, the Li in the recovery object is chlorinated by the chlorine element (Cl) separated from the metal chloride. Thus, lithium chloride (LiCl) is generated in the recovery object. Since the LiCl is easily soluble in water, it can be easily separated from the recovery object.

[0055] It should be noted that the "metal chloride" in the technology disclosed herein includes a second metal element that is easier to chlorinate than the first metal element in the recovery object and less likely to chlorinate than Li in the chlorination heating step S14. When the metal chloride containing such a second metal element is heated, Li can be selectively chlorinated without chlorinating the first metal element in the recovery object. Thus, lithium chloride (LiCl) can be efficiently generated.

[0056] The second metal element in the metal chloride is preferably, for example, Figure 6 The thermodynamic equilibrium state of each component in the recovery object shown is appropriately selected from various metal elements. Specifically, Figure 6 This is data showing the thermodynamic equilibrium state when a recovery object containing Li, Ni, Co, Mn, Al, and Cu is heated at 927°C (1200K). Figure 6 The horizontal axis represents the chlorine partial pressure (log 10 P Cl2 ·atm). In addition, the vertical axis represents the oxygen partial pressure (log 10 P O2 ·atm). It should be noted that Figure 6 The thermodynamic equilibrium state shown can be calculated and prepared by using thermodynamic data of each simple substance or compound.

[0057] Specifically, the second metal element in the metal chloride can be located on the line representing the balance between Li oxide and chloride (Li2O / LiCl balance), the line representing the balance between Li metal and chloride (Li / LiCl balance), the line representing the balance between the first metal element and chloride (M / MCl balance), and the line representing the balance between the first metal element and chloride (M / MCl balance). 2xThe balance of the metal oxide and the metal chloride of the first metal element (MO x / MCl 2x Surrounded by lines of balance Figure 6 The area selection of the oblique line portion in can set the metal element P of PO2 and PCl2. Moreover, by controlling the oxygen partial pressure in the chlorination heating process S14 as needed, it is possible to selectively chlorinate Li without chlorinating the first metal element in the recovery object. As an example of such a second metal element, alkaline earth metals (Ca, Mg, Ba, Sr, Ra, Be, etc.) and alkali metals (Na, K, Rb, Cs, Fr) can be cited. By using the chlorides of these second metal elements as a chlorine supply source, LiCl can be generated more appropriately. However, the second metal element in the technology disclosed herein is not limited to the above-mentioned elements, and is appropriately selected based on the thermodynamic equilibrium state of each component in the recovery object. As an example, Figure 6 As shown, when the recycling object includes Li, Ni, Co, Mn, Cu, and Al, alkaline earth metals (especially Ca and Mg) are preferably selected as the second metal element.

[0058] It should be noted that the ratio (Cl / Li) of the Cl amount in the metal chloride to the Li amount in the recovery object can be more than 1 times. Thus, the Li in the recovery object can be properly chlorinated. It should be noted that from the viewpoint of more efficiently generating LiCl, the above Cl / Li is preferably more than 2 times, more preferably more than 4 times, further preferably more than 6 times, and particularly preferably more than 8 times. On the other hand, the upper limit of Cl / Li is not particularly limited, and can be less than 20 times, less than 18 times, less than 16 times, less than 14 times, or less than 12 times.

[0059] In addition, the heating temperature in this process is set to 1000°C or less. According to the technology disclosed herein, even when the heating temperature is low, LiCl can be efficiently generated, so Li can be recovered with lower energy than before. It should be noted that the upper limit of the heating temperature is preferably 975°C or less, more preferably 950°C or less. As the heating temperature is lowered, the energy required for recovering Li can be further reduced. On the other hand, the lower limit of the heating temperature is preferably 800°C or more, more preferably 850°C or more, further preferably 900°C or more, and particularly preferably 925°C or more. There is a tendency that the generation efficiency of LiCl increases with increasing the heating temperature.

[0060] The pressure in the chlorination heating step S14 is not particularly limited and can be appropriately set. The details will be described later. The present inventors have confirmed that even at atmospheric pressure (about 1.0×10 5When the chlorination heating step S14 is carried out at 1.0×10 Pa, LiCl is also appropriately generated. On the other hand, there is a tendency that the generation efficiency of LiCl increases as the pressure of the chlorination heating step S14 is reduced. Specifically, the pressure in the chlorination heating step S14 is preferably 1.0×10 3 Pa or less, more preferably 7.5×10 2 Pa or less, more preferably 5.0×10 2 Pa or less, particularly preferably 2.5×10 2 On the other hand, the lower limit of the pressure in the chlorination heating step S14 is not particularly limited and may be 1.0×10 0 Pa or more, can be 5.0×10 0 Pa or more, can be 1.0×10 1 Pa or more, can be 5.0×10 1 Pa or above.

[0061] In addition, in this process, in order to control the oxygen partial pressure, the recovery object can be heated under an inert atmosphere. It should be noted that as a specific example of the heating gas used in this process, an inert gas such as argon 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 with an inert gas content of 100% (the oxygen content is 0%), but may also contain a very small amount of oxygen. 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).

[0062] In addition, in this process, it is preferred that the recovery object and the metal chloride are stored in different containers and heated. In this case, if the container of the recovery object is connected to the container of the metal chloride, the Li in the recovery object can be chlorinated. According to this configuration, the mixing of the second metal element of the metal chloride into the recovery object can be kept to the necessary minimum, so the reduction of the recovery efficiency of the valuable metal caused by the mixing of impurities can be prevented.

[0063] (2) Water dissolution step S20

[0064] Next, in the water dissolution step S20, the recovery object after the chlorination heating step S14 is immersed in water. As described above, the recovery object after the chlorination heating step S14 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 directly separated from the recovery object immediately after the chlorination heating step S14. As a result, a Li solution containing high-purity Li can be obtained.

[0065] 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.

[0066] (3) Li crystallization step S30

[0067] In this process, crystals of Li compounds are precipitated from the Li solution. In this process, a previously known crystallization process can be used 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. 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.

[0068] As described above, in the manufacturing method of this embodiment, Li can be directly 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.

[0069] (4) Sorting process S40

[0070] On the other hand, the first metal element (Ni, Co, Mn, Al, Cu, Fe, etc.) that is not chlorinated in the chlorination heating step S14 remains in the solid content (recycling object) after the water dissolution step S20. In contrast, in the manufacturing method of the present embodiment, valuable metals (Ni, Co, Mn) are recovered from the recycling object after the water dissolution step S20. Specifically, in the present embodiment, the sorting step S40 is implemented after the roasting step S10 is implemented. In this process, the various components contained in the recycling object after roasting are sorted with 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. Thus, 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, Mn). It should be noted that, as in the present embodiment, the sorting process is preferably implemented after the water dissolution process. Thus, LiCl attached to the removal object (positive electrode core, negative electrode plate, shell, etc.) in the sorting process can be recovered first.

[0071] 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.

[0072] In addition, the sorting process S40 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 (neutralization precipitation 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.

[0073] (5) Acid seepage step S50

[0074] In the acid seepage step S50, the solid component after the water dissolution step S20 is immersed in an acid solution. Thus, a metal solution in which the first metal element in the recovery object is dissolved in the acid solution can be obtained. It should be noted that the acid seepage step can adopt a conventionally known step without particular limitation. As an example, the pH of the acid solution used in this step is preferably -1.5 to 1.5 (more preferably -0.5 to 0.5). Thus, the metal component in the recovery object can be properly dissolved. It should be noted that as specific examples of the acid solution, inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, and organic acids such as citric acid, ascorbic acid, oxalic acid, and acetic acid can be cited. In addition, in this step, it is preferred to filter the metal solution after the acid seepage. Thus, undissolved components (carbon components, etc.) can be effectively removed. It should be noted that the temperature of the acid solution is preferably above 50°C (more preferably above 55°C, particularly preferably above 60°C). Thus, the acid seepage step S30 can be shortened. The upper limit of the acid solution temperature is not particularly limited, and may be 90° C. or lower, 85° C. or lower, or 80° C. or lower.

[0075] (6) Neutralization precipitation step S60

[0076] In this process, a neutralizing agent is added to the metal solution obtained in the acid seepage process S50. As a result, Al hydroxide (Al(OH)3) is precipitated and precipitated. As a result, Al can be almost removed from the metal solution containing Al, Cu, Co, Ni, Mn, etc. It should be noted that as a neutralizing agent used in this process, an alkaline solution with a pH of 11 to 15 (preferably pH 12 to 14) can be used. It should be noted that specific examples of neutralizing agents include aqueous sodium hydroxide solution, calcium hydroxide, ammonia, etc. In addition, in this process, it is preferred to filter the metal solution after Al(OH)3 precipitation. As a result, Al(OH)3 can be efficiently removed from the metal solution.

[0077] (7) Solvent extraction step S70

[0078] In this process, Co, Ni, and Mn are extracted from the metal solution by solvent extraction. Thus, Co solution, Ni solution, and Mn solution can be prepared respectively. In addition, in this process, impurities (such as Al) remaining in the metal solution can also be separated. Specifically, Figure 5 As shown, the solvent extraction step S70 in this embodiment includes a Mn extraction step S71, a Co extraction step S72, and a Ni extraction step S73.

[0079] (a) Mn extraction step S71

[0080] In this step, an organic solvent (first extract) having high extractability for Mn and low extractability for Li, Al, Cu, Co, and Ni is added to the metal solution. As the first extract, a phosphate extractant, an oxime extractant, and the like can be used. Specific examples of phosphate extractants include di-2-ethylhexyl phosphoric acid (D2EHPA). In addition, specific examples of oxime extractants include 2-hydroxy-5-nonylacetophenone oxime (LIX84), 5-dodecyl salicylaldehyde oxime (LIX860), and 5-nonyl salicylaldehyde oxime (ACORGA M5640). In addition, the first extract can be an extract obtained by mixing and diluting these extractants. Then, in this step, the metal solution and the first extract are stirred and suspended. As a result, Mn in the metal solution is dissolved in the first extract. Then, by standing until the two liquids are separated, a Mn solution in which Mn is dissolved in the first extract and a first extract from which Mn has been removed can be obtained.

[0081] In addition, in this process, the Mn solution after extraction (the first extract containing Mn) can be subjected to a stripping treatment. In the stripping treatment, first, the Mn 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 Mn solution in which Mn is dissolved in the acidic aqueous solution can be obtained. It should be noted that examples of the acidic aqueous solution used in the stripping treatment include sulfuric acid, hydrochloric acid, and the like (particularly sulfuric acid).

[0082] (b) Co extraction step S72

[0083] In this process, an organic solvent (second extract) with high extractability for Co and low extractability for Li, Al, Cu, and Ni is added to the metal solution. In this way, Co can be separated from the metal solution, and a Co solution in which Co is dissolved in the second extract can be obtained. It should be noted that as a specific example of the second extract, phosphonates such as 2-ethylhexylphosphonate (PC-88A) can be cited. In addition, the extracted Co solution (metal solution containing Co) can also be subjected to a back extraction treatment. In this way, an aqueous Co solution can be obtained. It should be noted that since the steps of the back extraction treatment have been described, repeated records are omitted.

[0084] (c) Ni extraction step S73

[0085] In this process, an organic solvent (third extract) with high Ni extraction property and low Li, Al and Cu extraction property 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 third extract can be obtained. It should be noted that as a specific example of the third extract, carboxylic acid extractants such as neodecanoic acid and cyclohexane acid can be cited. In addition, the extracted Ni solution (third 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.

[0086] (8) NCM crystallization step S80

[0087] In this process, crystals of metal compounds are precipitated from Co solution, Ni solution and Mn solution, respectively. In this process, the previously known crystallization treatment can be adopted without particular limitation. For example, when the stripping treatment is respectively implemented in Mn extraction process S71 to Ni extraction process S73, a mixed solution of an aqueous system mixed with Co solution, Ni solution and Mn solution is prepared. 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 each of the Co solution, Ni solution and Mn solution 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, spherical NiCoMn hydroxide (NCM precursor) can be crystallized.

[0088] (9) Active Material Generation Step S90

[0089] In this step, the metal compound obtained in the NCM crystallization step S80 and the Li compound obtained in the Li crystallization step S30 are used to generate a battery material (positive electrode active material). Specifically, NiCoMn hydroxide (NCM precursor) and a Li compound (Li2CO3, etc.) are mixed and calcined. Thus, a positive electrode active material (lithium transition metal composite oxide) for a lithium ion secondary battery can be manufactured.

[0090] 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 S14 is implemented to heat the recovery object together with the metal chloride. Moreover, the metal chloride used in the chlorination heating step S14 uses a chloride of a second metal element that is easier to chlorinate than the first metal element in the recovery object and less likely to chlorinate than Li. Thus, it is possible to selectively chlorinate Li without chlorinating the first metal element in the recovery object. As a result, lithium chloride (LiCl) can be efficiently generated even by heating at a low temperature below 1000°C. Moreover, in the manufacturing method of the present embodiment, a water dissolution step S20 is implemented to dissolve the LiCl in the recovery object in water. Thus, Li can be recovered from the recovery object with low energy.

[0091] 3. Other Implementation Methods

[0092] 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.

[0093] In the manufacturing method of the above embodiment, in addition to the roasting step S10 and the water dissolution step S20, the sorting step S40 and the Li crystallization step S30 to the active material generation step S90 are also implemented. However, the description of the above embodiment is not intended to limit the steps other than the roasting step S10 and the water dissolution step S20. That is, in the manufacturing method disclosed herein, the steps other than the roasting step S10 and the water dissolution step S20 can be appropriately added, deleted, or changed as needed.

[0094] (1) Changes in the solvent extraction process

[0095] For example, 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 Mn extraction process S71, a Co extraction process S72, and a Ni extraction process S73. Thus, the Co solution, the Ni solution, and the Mn solution can be extracted separately. However, in the solvent extraction process S70, multiple valuable metals can also be extracted simultaneously. For example, an organic solvent with high extractability for Ni and Co and low extractability for Li, Al, and Cu can be added to the metal solution after Mn extraction. Thus, Ni and Co can be extracted simultaneously. If multiple valuable metals are extracted simultaneously in this way, it is possible to improve manufacturing efficiency by shortening the process.

[0096] (2) Addition of Li separation step

[0097] In addition, the Li separation process can also be performed on the Li solution before the Li crystallization process S30 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 S30. It should be noted that the method for preparing the Li solution is not particularly limited, and it is preferred to appropriately adopt a previously known method such as a solvent extraction method and an ion exchange method.

[0098] (3) Addition of Li Concentration Process

[0099] In addition, the Li concentration process may also 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. Thus, a high-concentration Li solution can be obtained, thereby improving the crystallization efficiency in the Li crystallization process S30. 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, 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] (4) Changes in the NCM crystallization process

[0101] In addition, in the above-mentioned embodiment, the NCM crystallization step S80 is implemented on the mixed solution mixed with the Co solution, the Ni solution and the Mn solution. Thus, NiCoMn hydroxide can be crystallized as a metal compound containing Co, Ni and Mn. However, in the NCM crystallization step, the metal compound can also be crystallized separately from each of the Co solution, the Ni solution and the Mn solution. 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 manganese sulfate (MnSO4) can be precipitated from the Mn solution. In addition, crystals of cobalt sulfate (CoSO4) are precipitated from the Co solution. Moreover, crystals of nickel sulfate (NiSO4) are precipitated from the Ni solution. By mixing the NCM hydroxide synthesized from the crystals of these sulfates with a Li compound and calcining it, a battery material (positive electrode active material) can be generated.

[0102] [Test example]

[0103] 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.

[0104] 1. Sample Preparation

[0105] In this test, six types of recovery treatments with different conditions in the calcination step were performed. Hereinafter, six types of test samples (Examples 1 to 6) obtained in each recovery treatment will be described.

[0106] (1)Example 1

[0107] In Example 1, a mixture of positive plates and negative plates is used as the recycling object, and a roasting process is performed on the recycling object. Specifically, as the positive plate, a positive plate with a positive electrode active material layer coated on the surface of the positive electrode core (Al foil) is used. Then, the positive electrode active material is lithium nickel cobalt manganese composite oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2). On the other hand, as the negative electrode plate, a negative electrode plate having a negative electrode active material layer coated on the surface of the negative electrode core (Cu foil) is used. Then, graphite is used as the negative electrode active material. Then, these positive and negative plates are cut into 1 cm × 3 cm sheets and prepared as recycling objects.

[0108] Next, in this experiment, a roasting process is performed to heat the recycling object and the metal chloride (CaCl2) together. Specifically, in the roasting process of this experiment, a double-structured glass tube is prepared. Next, the recycling object is stored in the inner glass tube, and the metal chloride is stored in the outer glass tube. It should be noted that in this experiment, the amount of metal chloride is adjusted in such a way that the ratio of the amount of Cl in the metal chloride to the amount of Li in the recycling object (Cl / Li) is 10 times. Next, the pressure in the glass tube is 2.0×10 2 Pa. Then, the glass tube is placed in an electric furnace and the temperature in the furnace is raised to 927°C. It should be noted that the heating rate at this time is set to 10°C / min. Then, the furnace temperature is maintained at 927°C and roasting is performed for 1 hour. Then, the temperature in the furnace is cooled to 50°C and the recovered object is recovered. In this test, the recovered object after heating is used as a test sample (Example 1).

[0109] (2)Example 2

[0110] In Example 2, the calcination step was carried out under the same conditions as in Example 1 except that the type of metal chloride was changed to NaCl2.

[0111] (3)Example 3

[0112] In Example 3, the calcination step was carried out under the same conditions as in Example 1 except that the metal chloride was changed to MgCl2.

[0113] (4)Example 4

[0114] In Example 4, the calcination step was carried out under the same conditions as in Example 1 except that no metal chloride was used.

[0115] (5)Example 5

[0116] In Example 5, the calcination step was carried out under the same conditions as in Example 1 except that the heating temperature was lowered to 727°C.

[0117] (6)Example 6

[0118] In Example 6, the calcination step was carried out under the same conditions as in Example 1, except that the heating was performed (under atmospheric pressure) without reducing the pressure in the glass tube.

[0119] 2. Evaluation test

[0120] In this test, the test samples of Examples 1 to 6 were immersed in water for 30 minutes to obtain a Li solution, and then the Li solution was filtered to remove the solid content. Then, the filtered Li solution was subjected to ICP to measure the amount of Li in the Li solution. Then, the recovery rate of each element was calculated based on the following formula. The measurement results are shown in Table 1. It should be noted that the "metal element amount before calcination" in the formula is the metal element amount obtained by analyzing the reference sample before calcination using ICP.

[0121] Recovery rate = (amount of metal elements in Li solution / amount of metal elements before calcination) × 100

[0122] [Table 1]

[0123]

[0124] According to the test results, a high Li recovery rate of 70% or more was confirmed in Examples 1, 3, 5, and 6. This shows that if an appropriate metal chloride is selected in the calcination step, Li can be appropriately recovered even when a low temperature heating treatment of 927° C. or less is performed.

[0125] 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.

[0126] <Project 1>

[0127] A method for manufacturing a battery material, comprising:

[0128] A preparation step of preparing a recovery object including lithium and a first metal element;

[0129] a chlorination heating step, heating the above-mentioned recovery object and metal chloride together to generate LiCl; and

[0130] A water dissolution step, 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;

[0131] The heating temperature in the chlorination heating step is below 1000°C.

[0132] The metal chloride includes a second metal element that is more easily chlorinated than the first metal element in the recovery target and less easily chlorinated than the lithium in the chlorination heating step.

[0133] <Project 2>

[0134] According to the method for manufacturing a battery material as described in Item 1, the first metal element includes at least one selected from Ni, Co, Mn, Al, Cu, and Fe.

[0135] <Project 3>

[0136] The method for producing a battery material according to item 1 or 2, wherein the second metal element includes at least one selected from Ca, Mg, Ba, Sr, Ra, and Be.

[0137] <Item 4>

[0138] The method for producing a battery material according to any one of items 1 to 3, wherein the heating temperature is 800° C. or higher.

[0139] <Item 5>

[0140] The method for producing a battery material according to any one of items 1 to 4, wherein the chlorination heating step is performed under a reduced pressure environment of 500 Pa or less.

[0141] <Item 6>

[0142] The method for producing a battery material according to any one of items 1 to 5, further comprising: a Li precipitation step of precipitating a crystal of a Li compound from the Li solution.

[0143] <Item 7>

[0144] The method for producing a battery material according to any one of items 1 to 6, further comprising: an acid seepage step of immersing the solid material after the water dissolution step in an acid solution to obtain a metal solution in which the first metal element is dissolved in the acid solution.

Claims

1. A method for manufacturing a battery material, comprising: A preparation step of preparing a recovery object including lithium and a first metal element; a chlorination heating step, heating the recycling object and metal chloride together to generate LiCl; and A water dissolution step, immersing the recovery object after the chlorination heating step in water to obtain a Li solution in which the LiCl is dissolved in the water; The heating temperature in the chlorination heating step is below 1000°C. The metal chloride includes a second metal element that is more easily chlorinated than the first metal element in the recovery target and less easily chlorinated than the lithium in the chlorination heating step.

2. The method for producing a battery material according to claim 1, wherein: The first metal element includes at least one selected from Ni, Co, Mn, Al, Cu, and Fe.

3. The method for producing a battery material according to claim 2, wherein: The second metal element includes at least one selected from Ca, Mg, Ba, Sr, Ra, and Be.

4. The method for producing a battery material according to claim 1, wherein: The heating temperature is above 800°C.

5. The method for producing a battery material according to claim 1, wherein: The chlorination heating step is 5.0×10 2 It is carried out in a reduced pressure environment of less than Pa.

6. The method for producing a battery material according to claim 1, wherein: Further including: The Li precipitation step is to precipitate crystals of a Li compound from the Li solution.

7. The method for producing a battery material according to claim 1, wherein: Further including: The acid leaching step is to immerse the solid material after the water dissolution step in an acid solution to obtain a metal solution in which the first metal element is dissolved in the acid solution.

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