JPH10255862A - Valuable material separating method from lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover a valuable material such as rare metal from a used secondary lithium ion battery at a high recovering rate by soaking an electrode of the used secondary lithium ion battery in an acidic solution or the like, and separating the electrode into an electrode material and a current collecting body. SOLUTION: A used secondary lithium ion battery is disassembled, and an electrolyte is completely removed from an electrode, and is soaked in a solvent, and is cleaned. This electrode is soaked in any one of an acidic solution (such as hydrogen halide, sulfuric acid, hydrogen peroxide, nitric acid, etc.), a hydroxide solution of alkaline metal (such as sodium hydroxide or potassium hydroxide), an alcohol solution (such as a lithium alkoxide, sodium alkoxide, etc.) of alkaline metal or an organic solvent (such as ketone and ester), and is separated into an electrode material and a current collecting body. This electrode material is soaked in the acidic solution, and after valuable metal is dissolved, the valuable metal can be inexpensively recovered with high purity by chemical treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating valuables from a lithium ion secondary battery used for recovering valuables contained in the lithium ion secondary battery. The present invention relates to a method for separating valuable materials from a lithium ion secondary battery that can be recovered at low cost and with high purity.

[0002]

2. Description of the Related Art In recent years, non-aqueous electrolyte batteries have attracted attention as high energy density batteries, and as various electronic devices such as VTRs and communication devices have been reduced in size and weight, they have been used as power sources for these devices. Unlike conventional rechargeable batteries, lithium-ion rechargeable batteries do not contain harmful metals such as mercury, cadmium, and lead, and their characteristics also have a good cycle life. I am following.

[0003] By the way, the currently mainstream materials used as the positive electrode material of lithium ion secondary batteries or the materials listed as candidates for the next period are all rare metals designated as national stock materials. Therefore, attention has been paid to a method of recycling these materials contained in a used lithium ion secondary battery.

Conventional methods for recovering valuable metals from lithium ion secondary batteries include, for example, Japanese Patent Application Laid-Open No. 7-2073.
One described in Japanese Patent Publication No. 49 is known. In this recovery method, used lithium ion secondary batteries are baked, sifted, pulverized, baked, acid-treated, and then subjected to sedimentation to recover valuable metals. According to this recovery method, a relatively good recovery rate can be obtained, but nickel, iron, and cobalt cannot be completely separated, so that high-purity recovery cannot be performed. Further, Japanese Patent Application Laid-Open No. 7-245126 describes a method of cultivating, sifting, and pulverizing a used lithium-ion secondary battery, and then sorting magnetically to collect valuable metals. According to this method, although the cost is low because it is separated from the housing portion (magnetic material) by sieving, the purity of the recovered material is very poor. JP-A-8-22846 discloses that a used lithium ion secondary battery is immersed in an alkali,
A method is described in which, after separating a positive electrode material and a negative electrode sheet, the positive electrode material is burned to recover the active material, and the negative electrode sheet is separated from the housing and burned, and recovered as Cu foil.
According to this method, it is possible to use the active material as it is or to mix it with a new active material. However, since a large amount of CO ₂ is generated by combustion and the material is not purified, it can be used as an active material. There is a risk of contamination of impurities,
Since the active material has a state in which the amount of Li is smaller than the theoretical amount, there is a disadvantage that it is impossible to use it as it is in reality.

[0005]

As described above, when a valuable metal contained in a used lithium ion secondary battery is recovered by a conventional recovery method, cost and purity of the recovered valuable metal are reduced. Still not enough.

The present invention has been made in view of the above circumstances, and an object of the present invention is to improve the recovery rate of valuable materials from used lithium ion secondary batteries, and to recover them at low cost and high purity. It is an object of the present invention to provide a method for separating valuables from a lithium ion secondary battery that enables the separation.

[0007]

The most important thing in recovering valuable materials from a lithium ion secondary battery is the recovery of the electrode and the positive electrode active material. In particular, at present, lithium cobalt oxide is mainly used as a positive electrode active material, and a method for recovering this expensive cobalt has been widely studied. In order to recover such an electrode and a positive electrode active material with a high recovery rate, low cost, and high purity, it is necessary to reliably separate the current collector from the positive electrode active material. Since these are adhered very strongly by a binder or the like, it is not easy to decompose them by physical operation.

As a result of intensive studies, the present inventors have found that the electrodes of a lithium ion secondary battery are immersed in a predetermined acidic solution, alkali metal hydroxide solution, alkali metal alcohol solution or organic solvent. It has been found that the electrode material and the current collector can be separated more easily. Further, by heating the electrode at a predetermined temperature to volatilize the organic binder and reduce the adhesiveness between the current collector and the electrode material, the electrode material and the electrode material are immersed in a solvent such as water. It has been found that the current collector can be easily separated.

That is, a feature of the present invention is that the electrode of a lithium ion secondary battery that has been dismantled in advance is immersed in one of an acidic solution, an alkali metal hydroxide solution, an alkali metal alcohol solution and an organic solvent. And separating the electrode into an electrode material and a current collector.

Here, in the case of a lithium ion secondary battery using aluminum as the positive electrode current collector and copper as the negative electrode current collector, the acidic solution may be a hydrohalic acid such as hydrofluoric acid, sulfuric acid, It is preferable to use at least one of hydrogen peroxide, acetic acid, nitric acid, fuming nitric acid, and perchloric acid. Further, as the hydroxide solution of the alkali metal, it is preferable to use at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide in an aqueous solution or a molten state. It is preferable to use at least one of lithium alkoxide, sodium alkoxide and potassium alkoxide as the alcohol solution of the alkali metal. It is preferable to use at least one of ketone, ester, ether, alcohol, acetonitrile and aliphatic hydrocarbon as the organic solvent.

[0011]

Embodiments of the present invention will be described below in detail.

First, a general lithium ion secondary battery will be described. FIG. 1 is a cross-sectional view showing a configuration of a general bottomed cylindrical lithium ion secondary battery. A cylindrical container 1 with a bottom has an insulator 2 disposed at the bottom. The electrode group 3 is housed in the container 1. Electrode group 3
Has a structure in which a belt-like material in which a positive electrode 4, a separator 5, and a negative electrode 6 are laminated in this order is spirally wound so that the negative electrode 6 is located outside. A non-aqueous electrolyte is contained in the container 1. The insulating paper 7 whose center is opened is placed above the electrode group 3 in the container 1. The insulating sealing plate 8 is disposed in the upper opening of the container 1, and the sealing plate 8 is liquid-tightly fixed to the container 1 by caulking the vicinity of the upper opening inward. The positive terminal 9 is fitted in the center of the insulating sealing plate 8. One end of the positive electrode lead 10 is connected to the positive electrode 4, and the other end is connected to the positive electrode terminal 9. The negative electrode 6 is connected to the container 1 as a negative electrode terminal via a negative electrode lead (not shown).

Next, disassembly of the lithium ion secondary battery will be described. The method for separating valuable resources of a lithium ion secondary battery according to the present embodiment is based on the premise that the lithium ion secondary battery has been dismantled in advance.

In general, what is called "used lithium ion secondary battery" includes not only batteries having a normal cycle life but also batteries that have become unusable due to overcharge, overdischarge, or the like. In the case of a battery with a normal cycle life, lithium that is deposited on the negative electrode as metallic lithium during charging dissolves in the electrolyte as lithium ions during discharging, so if discharged before disassembly, the battery can be used without danger. Cutting is possible. On the other hand, in the case of a battery that has become unusable due to overcharging or the like, the safety device operates due to an increase in battery internal pressure, an increase in battery temperature, and the like, so that subsequent discharge becomes impossible. Therefore, the lithium ion secondary battery must be disassembled in a charged state, that is, while the metallic lithium is deposited on the negative electrode. Therefore, it is necessary to cut the battery in an inert gas atmosphere, a non-aqueous solvent, or an inert solution to avoid danger.

Specifically, first, the used lithium ion secondary battery packaged is discharged. As a result, in a battery having a normal cycle life, the metal lithium that has been deposited on the negative electrode is dissolved in the electrolyte as lithium ions. After the discharge, the entire package is cut. The cutting direction is not particularly limited, and the cutting direction may be perpendicular or parallel to the longitudinal direction of the battery. However, in the case of cutting vertically, several cuttings are required. Further, as described above, it is desirable that the cutting is performed in an inert gas or an inert solution.

After disassembling the battery by the above-described method, the electrolyte is completely removed from the electrodes. As a method therefor, there is a method of immersing in a solvent for washing. In general, the electrolyte of a lithium ion secondary battery includes propylene carbonate (PC), 1,2-dimethoxyethane (DME),
LiClO ₄ , LiB in a non-aqueous solvent such as γ-butyrolactone (γ-BL), tetrahydrofuran (THF), diethoxyethane, ethylene carbonate (EC)
A solution in which an electrolyte such as F ₄ , LiAsF ₆ or LiPF ₆ is dissolved is used. These have high solubility in polar solvents such as water and alcohol.However, using water for the cleaning solution involves danger due to the presence of metallic lithium precipitated on the negative electrode. Is safe. Also, when using an alcohol that does not form an azeotrope with water such as methanol for the washing solution,
Since the electrolyte, the electrolytic solution, and the cleaning solution can be separated by vacuum distillation, they can be reused.

Here, the following matters must be taken into account during the above-mentioned cleaning. First, since the positive electrode material containing the positive electrode active material may be separated from the current collector, it is necessary to perform an operation of collecting them from the cleaning solution by filtration or the like. When lithium cobalt oxide, aluminum for the positive electrode current collector, and copper for the negative electrode current collector, some cobalt, aluminum, and copper are dissolved in the electrolytic solution. Third, dissolution of the battery can Therefore, iron, nickel, and the like coexist. These are due to the fact that a trace amount of water in the non-aqueous solvent decomposes the electrolyte, thereby generating an acidic substance in the electrolyte, and dissolving and corroding the metal of the electrode and the container and the like in a portion that comes into contact with the electrolyte. Things. Therefore, when recovering the electrolyte and the electrolytic solution, it is necessary to recover these metal ions.

After washing the battery, various materials are selected and separated into a battery package, a battery housing, a positive electrode, a negative electrode, a separator, and the like.

Next, a method for separating valuables from a lithium ion secondary battery according to an embodiment of the present invention will be described.

(1) Method of Separating Electrode Material and Current Collector by Dipping in Acid Solution According to this method, the current collector can be easily separated from the electrode material, and can be recovered as a single metal. can do. Since a part of the active material component in the electrode material is also dissolved, it is necessary to recover the metal component in the solution. However, since the current collector component is hardly contained in the solution, the recovery operation is easy.

Here, the acidic solution may be an oxidizing acidic solution or a non-oxidizing acidic solution. These solutions are
Select according to the material to be separated and collected. The valuable resources to be collected in the electrode are a positive electrode active material, a positive electrode current collector, and a negative electrode current collector. Generally, a metal is used as a current collector material of an electrode, and an oxide is used as a positive electrode active material material. Therefore, a positive electrode active material and a positive electrode current collector, and a negative electrode active material and a negative electrode current collector are mixed with an acidic solution. In the case of separation by the above, it is necessary to select an acidic solution according to each current collector material. For example, to recover a positive electrode active material when aluminum is used for the positive electrode current collector, aluminum must form an acid-insoluble passivation on its surface with respect to an oxidizing acidic solution (for example, nitric acid). By utilizing, it is possible to separate from the current collector while minimizing the dissolution of aluminum. However, since the aluminum passivation is dissolved by heating, this separation operation must be performed in a cold state. On the other hand, when copper is used for the negative electrode current collector, copper is not dissolved in a non-oxidizing acidic solution (for example, a hydrohalic acid or thiosulfate solution) at the time of cooling,
Further, by utilizing the fact that there is acid solubility at the interface between the negative electrode current collector and the negative electrode active material, the current collector and the active material can be separated and the current collector can be recovered as a metal. Further, only the negative electrode current collector is dissolved by an oxidizing acidic solution, and after performing treatment such as electrolysis, concentration, or heating, the metal, oxide,
It can be recovered as salt or the like. In addition, peelability can be improved by using an ultrasonic cleaner in combination with the above collection operation. However, it cannot be applied to the case of an aluminum current collector. This is because the aluminum and the electrode material are partially finely divided, so that it is somewhat difficult to physically separate the aluminum and the electrode material.

(2) Method of Separating Electrode Material and Current Collector by Dipping in Alkali Metal Hydroxide Solution or Alkali Metal Alcohol Solution According to this method, only the positive electrode current collector, aluminum, is dissolved. Therefore, it can be separated from the remaining electrode material in the form of a foil. In addition, at this time, by using an ultrasonic cleaner in combination, in addition to the solvents other than the above, the releasability of almost all solvents such as water is improved, and the negative electrode active material and the negative electrode current collector can be separated. become. In this case, since both the positive electrode material and the negative electrode material are finely divided, the filtration operation is somewhat complicated. As the alkali metal, any material that can dissolve the aluminum foil when it is made into a solution, and any material that does not dissolve the active material component may be used, such as sodium, lithium, and potassium. And an aqueous solution of an alkali metal or an alcohol solution.

(3) Method of Separating Electrode Material and Current Collector by Dipping in Organic Solvent This method can separate both the current collector and the positive electrode active material without dissolving them, Since there is no generation of gas and the like, the method is simple and extremely easy to perform the recovery operation. When a water-insoluble solvent is used, the solvent can be repeatedly used without requiring a solvent recovery operation such as fractional distillation. As the organic solvent, at least one solvent selected from ketones, esters, ethers, alcohols, acetonitrile, and aliphatic hydrocarbons can be used, and can be peeled off by soaking at room temperature for 1 hour or more. Also, if an ultrasonic cleaning device is used together, the stripping time can be reduced to about 1/6. However, care must be taken because the electrode material is finely divided regardless of time, and when the stripping time is long, a part of the aluminum current collector is also finely divided.

(4) Method of Separating Electrode Material and Current Collector by Heating According to this method, the fluororesin used as a binder for the electrode material is completely decomposed, and the adhesion of the electrode material is reduced. Thus, the electrode material and the current collector can be easily separated. When the heating temperature is set to 300 ° C. or higher, there is a problem that the fluorine-based resin used as a binder of the electrode material gradually starts to decompose, and the amount of fluorine volatilized increases with the heating time. This fluorine reacts with moisture in the air to generate hydrofluoric acid, which not only accelerates the deterioration of the heating furnace, but also requires an exhaust gas treatment facility during heating due to the need to remove harmful substances. Therefore, if heating is performed in a ceramic electric furnace having an acidic gas collecting tube, heat treatment can be performed without being affected by an acidic gas such as hydrofluoric acid. On the other hand, when the heating temperature is set to 300 ° C. or less,
If LiPF _{6 as an} electrolyte remains in the electrode material or the like, fluorine, phosphoric acid, phosphorous trifluoride, phosphorous oxyfluoride, etc. volatilize at about 100 ° C. where water and alcohol used for cleaning volatilize. Therefore, oil rotary pumps and piston pumps having gas collection tubes in advance, multi-stage steam ejectors,
It is necessary to reduce the contamination of harmful substances by suction drying with a vacuum pump such as a pump. Note that the heating temperature is 500 ° C.
In the case described above, the harmful gas such as dioxin is included in the waste gas, so that the heating temperature is 300 to 500 ° C.
It is preferable to set

When the electrode material is separated by a method in which the electrode material is not formed into fine particles in the above-described electrode solution separated by an acidic solution, an organic solvent, heating, or the like, the electrode material and the current collector may be separated by vibration filtration or jet flow. Is suitable. In the method using vibration filtration, the electrode material and the current collector in the form of a foil are placed on a mesh having a mesh width of 10 mm or less and an amplitude of 10
The electrode material is pulverized by vibrating at a frequency of 1000 mm / sec or less and the electrode material is pulverized, and separated by shaking it down under a net. On the other hand, in the method using a jet, a water jet is applied to an electrode having a reduced adhesion rate due to heating or the like.
The separation is performed by applying energy such as a water vapor jet or an air jet so that only the electrode material is pulverized, and it is a very simple method without adding a reagent or the like.

In the case where the electrode material is pulverized by using an acidic solution and an ultrasonic cleaner together, the positive electrode current collector and the electrode material are separated by a sieve of 100 mesh or less made of a material which is not attacked by acid. Then, a coagulant is added to the solution containing the separated electrode material to coagulate an acid-insoluble component other than the positive electrode active material such as a binder, and the separation can be easily performed by filtration or centrifugation.

When the electrode material is pulverized by using an organic solvent and an ultrasonic cleaner together, the electrode material can be separated by the same operation as the above-mentioned acidic solution. However, a method of separating by evaporating the solvent is further used. It is simple.

The positive electrode active material to be recovered in the electrode material separated by the above operation has a smaller Li / M (M = Co, Mn, Ni) ratio than the composition immediately after the preparation of the electrode material. Therefore, the cathode material cannot be reused as it is. Therefore, it is necessary to separate and collect the positive electrode active material for each component. Since the electrode material separated by a method other than the method of volatilizing the binder component by the heating operation contains the binder, it is necessary to separate the positive electrode active material and the binder. As a separation method, a method in which the binder component is volatilized by heating may be used.However, it is easier to reuse lithium and the transition metal as a single substance in a separated state. Only a method of dissolving and separating from the binder is good. As the acidic solution, the positive electrode active material is dissolved using hydrochloric acid, nitric acid, sulfuric acid, perchloric acid, a mixed solution thereof, a mixed solution with hydrogen peroxide solution, or the like. This solution is filtered to obtain a mixed solution of valuable metal ions such as lithium, cobalt, manganese, and nickel. This valuable metal ion mixed solution is separated as a single component by a method such as ion exchange, electrolysis, and precipitation separation.
Recover as oxides or metals.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the above-described embodiment of the present invention will be described below in detail.

The lithium ion secondary batteries in the following examples were manufactured as described below.

1.05 mol of lithium carbonate, 1.90 mol of cobalt oxide and 0.084 mol of stannic oxide were mixed in a mortar, calcined at 650 ° C. for 5 hours, and then 850 in air.
° C., the composition Li _1.03 obtained by calcining for 12 hours Co _{0.9 5}
The lithium cobalt oxide of Sn _0.042 O ₂ is ball-milled to produce a powder having an average particle diameter of 3 μm. 80% by weight of this lithium cobaltate powder and acetylene black 15
The mixture consisting of 5% by weight of polytetrafluoroethylene powder and 5% by weight of polytetrafluoroethylene powder was kneaded with isopropiniol alcohol to form a paste, which was then applied to an aluminum foil as a current collector, dried, and roll-pressed to form a sheet. A positive electrode in the shape of was prepared.

On the other hand, the phenol resin powder was calcined in nitrogen gas at 1700 ° C. for 2 hours and then ball-milled to obtain 96% by weight of a carbonaceous substance powder having an average particle size of 2 μm and 4% by weight of polytetrafluoroethylene powder. The resulting mixture was kneaded using isopropyl alcohol, applied to a copper foil as a current collector, dried, and roll-pressed to produce a sheet-shaped negative electrode.

The positive electrode, the separator made of a porous polypropylene film, and the negative electrode were laminated in this order, and then spirally wound so that the negative electrode was located outside, thereby producing an electrode group.

Further, 1.0 mol of lithium hexafluorophosphate (LiPF ₆ ) was dissolved in 1 L of a mixed solvent of ethylene carbonate, propylene carbonate and 1,2-dimethoxyethane (mixing volume ratio: 40:40; 20), and The water electrolyte was adjusted.

The electrode group is housed in a stainless steel bottomed cylindrical container.

The positive electrode lead (aluminum) and the negative electrode lead (nickel) are welded, and the nonaqueous electrolyte is injected by a reduced pressure method.

An aluminum sealing valve, which is a safety release valve when the internal pressure of the battery rises, and a current cutoff device, and a PTC (Positive Temperature Coeffic) for cutting off the current when a predetermined temperature is reached.
ient) An element, an insulating plate, and a cap are attached, caulking is performed, the cylindrical lithium secondary battery shown in FIG. 1 is assembled, and a cover made of polyvinyl chloride is attached to the battery.

A lead made of nickel-plated iron is welded to the positive electrode lid and the bottom of the can, and a protection circuit for overcharging and discharging is attached.
Finally, the battery pack is loaded into a battery pack made of polycarbonate (PC).

The prepared battery was operated at a current of 50 mV and a voltage of 4.2 V.
The charging and discharging cycle of charging the battery until it reaches 2.7 V with a current of 50 mV is repeated 500 times.

Subsequently, a 15 Ω resistor was attached to the battery,
A constant current discharge is performed at a speed of 300 mA / h. The current value is
When the current becomes 10 mA or less, the discharge is stopped.

Example 1 After the above-described discharged lithium ion secondary battery was cut by a cutter in an Ar gas atmosphere,
It is placed in a beaker made of polytetrafluoroethylene (PTFE) containing a methanol solution, and is cleaned using an ultrasonic cleaner. This operation is repeated three times while changing the methanol solution. The methanol solution used for washing was transferred to a glass beaker, heated and evaporated, and the residue was heated and decomposed by adding 5 ml of aqua regia, transferred to a 100-ml volumetric flask, and made constant in volume by 1CP (inductively coupled plasma) emission spectroscopy. Fe,
Ni, Al, Cu, Co and Sn were measured for Li by the atomic absorption method, and the amount of metal ions contained in the electrolytic solution per one battery was calculated. Table 1 shows the results.

[0042]

[Table 1] Table 1 Amount of metal ions contained in the electrolytic solution per battery (mg / battery) P Li Cu Co Fe Ni Al Sn Sn 865 33.4 0.45 1.02 0.47 0.023 0.16 0.27

After separating the electrode group having been subjected to the methanol washing from the battery housing, a polyvinyl chloride cover, a polycarbonate bag, a lead, and various safety devices, 10 ^-1 Torr
After 15 minutes, when the surface is completely dried, the electrode group is further separated into a separator, a positive electrode, and a negative electrode.

The positive electrode and the separator were placed in a glass beaker, 200 ml of 1 N nitric acid was added, and the mixture was stirred at 100 rpm using a magnetic stirrer.
l) After peeling off the electrode material from the foil, 5mm
Filter through a mesh sieve. After washing with water, the residue on the sieve is dried, and the sieve is oscillated at an amplitude of 50 mm and a frequency of 2 times.
By vibrating at s / sec, the electrode material was pulverized and separated from the positive electrode current collector and the separator.

Further, 50 ml of 6N hydrochloric acid was added to the electrode material to dissolve the positive electrode active material, and then a coagulant (Cliflock P) was added.
A-312) was added to coagulate and precipitate the acid-insoluble material, and 5 μm
Through a polyvinylidene fluoride (PVDF) filter.

The solution obtained when the filtrate and the positive electrode material and the positive electrode current collector were separated with the above 1N nitric acid was transferred to a 1000 ml volumetric flask, diluted with water, and the volume was fixed. , Ni, Al, Cu, and P were measured, and the amount of metal impurities mixed into the positive electrode material during 1N nitric acid peeling was calculated. Table 2 shows the results.

[0047]

Table 2 Table 2 Amount of metal impurities mixed in the positive electrode material at the time of peeling (g / one battery) Stripping conditions Al Cu Fe Ni P 1N nitric acid 0.033 <0.0002 0.0008 0.002 <0.0055 6N nitric acid 0.010 <0.0002 0.0007 0.002 <0.005 250 ° C heating, water 0.015 <0.0002 0.0008 0.002 <0.005 400 ° C heating, water 0.005 <0.0002 0.0008 0.002 <0.005

On the other hand, after measuring the weight of the positive electrode current collector separated with 1N nitric acid, 50 ml of hydrochloric acid was added to dissolve
Transfer to a 00 ml volumetric flask, measure the volume, measure Fe, Ni, Cu, Co, Sn, P by ICP emission spectroscopy and Li by atomic absorption spectroscopy, and include in the positive electrode current collector per battery The amount of impurities to be collected was measured, and the recovery rate of the recovered Al was calculated. Table 3 shows the results.

[0049]

Table 3 Table 3 Impurity amount and recovery rate of recovered Al foil (g / battery) Recovery rate Peeling conditions Cu Sn Fe Ni Co P Li (%) 1N nitric acid <0.0002 <0.0005 0.006 <0.0002 <0.0002 < 0.005 <0.0002 97.3 6N nitric acid <0.0002 <0.0005 0.006 <0.0002 <0.0002 <0.005 <0.0002 98.7 250 ° C heating, water <0.0002 <0.0005 0.006 <0.0002 <0.0002 <0.005 <0.0002 98.3 400 ° C heating, water <0.0002 <0.0005 0.007 <0.0002 <0.0002 <0.005 <0.0002 99.0

On the other hand, 100 ml of 1 N hydrochloric acid was added to the negative electrode separated after the methanol washing, and the mixture was left for 10 minutes using an ultrasonic cleaner (45 kHz) to remove the negative electrode active material from the negative electrode current collector (Cu foil). The material is exfoliated. After filtration and washing with a 5 mm mesh sieve made of polypropylene, the residue (Cu foil) on the sieve is dried, and the weight is measured. Further, 50 ml of nitric acid was added to dissolve the Cu foil, then transferred to a 100 ml volumetric flask, made to a constant volume, and subjected to ICP emission spectroscopy.
e, Ni, Al, Co, Sn, P are converted to Li by atomic absorption
Was measured, the amount of impurities contained in the negative electrode current collector per battery was measured, and the recovery rate of the recovered Cu was calculated. Table 4 shows the results.

[0051]

Table 4 Recovered Cu impurity amount and recovered rate (g / battery) recovered rate Stripping conditions Al Sn FeNiCoPLi (%) Cu foil <0.0002 0.001 <0.0002 <0.0002 <0.0002 <0.005 < 0.0002 98.7 Electrolytic Cu <0.0002 <0.0005 <0.0002 <0.0002 <0.0002 <0.005 <0.0002 99.5

(Example 2) After the electrode group was separated in the same manner as in Example 1, the negative electrode was dissolved in a mixed acid of nitric acid and sulfuric acid (50 ml), and water was added to make the total amount to about 1200 ml. A cylindrical platinum cathode and a plate-shaped platinum anode were placed so that the upper ends thereof were 5 mm above the liquid level. At room temperature, a current of 0.5 A was passed, and after electrolysis for 3 hours, water was added. The liquid level is raised by 5 mm, and electrolysis is further performed for 30 minutes. Lastly, if Cu was not precipitated in the part immersed in the solution, the electrolysis was stopped, and after measuring the weight of the precipitated Cu, 50 ml of nitric acid was further added to dissolve the precipitated Cu, transferred to a 1000 ml volumetric flask, Constant volume, ICP emission spectroscopy, Fe, Ni, Al, C
For o, Sn, and P, Li was measured by the atomic absorption method, the amount of impurities contained in the negative electrode current collector per battery was measured, and the purity and recovery rate of the recovered Cu were calculated. The results are shown in Table 4 above.

Example 3 The same operation as in Example 1 was performed except that 6N nitric acid was used to separate the positive electrode material and the positive electrode current collector. The results are shown in Table 2 above.

Example 4 In the same manner as in Example 1, 200 ml of a 1N sodium hydroxide solution was added to the electrode group after washing to dissolve the positive electrode current collector, followed by filtration through a polypropylene sieve (50 mesh) and washing with water. I do. The filtrate is hydrochloric acid 50
ml, acidified, transferred to a 1000 ml volumetric flask, and, after constant volume, Fe, Ni, C by ICP emission spectroscopy.
o, Sn, Cu, and P were measured, and the amount of impurities contained in the positive electrode current collector per battery was calculated. Table 5 shows the results.

[0055]

Table 5 Table 5 Stripping conditions of metal impurities (g / one battery) in Al solution by alkali solution separation Cu Sn Fe Ni Co P Li 1N NaOH 0.006 0.002 <0.0002 <0.0002 0.002 <0.005 <0.0002 6N NaOH 0.007 0.003 <0.0002 <0.0002 0.003 <0.005 <0.0002 Sodium _{0.006 0.002 <0.0002 <0.0002 0.002 <0.005 <0.0002} Ethoxide

On the other hand, the positive electrode material and the negative electrode
After being immersed in a normal hydrochloric acid solution and subjected to ultrasonic cleaning in the same manner as in Example 1 to obtain a slurry of the negative electrode current collector and the active material, the slurry was separated by filtration, and the same operation as in Example 1 was performed. Each was dissolved and component analysis was performed. Table 6 shows the results of the impurity amount, purity, and recovery rate of the negative electrode current collector, and Table 7 shows the results of impurity analysis in the positive electrode material.

[0057]

Table 6 Conditions for stripping metal impurities (g / one battery) in Cu foil by alkali solution separation AlSnFeNiCoPLiNa 1N NaOH <0.0002 <0.0005 <0.0002 <0.0002 <0.0002 <0.005 0.0003 0.003 6 Specified NaOH <0.0002 <0.0005 <0.0002 <0.0002 <0.0002 <0.005 0.0005 0.007 Sodium _{<0.0002 <0.0005 <0.0002 <0.0002 <0.0002 <0.005 0.0004 0.006} Ethoxide

[0058]

Table 7 Table 7 Conditions for stripping metal impurities (g / one battery) in positive electrode material by alkali solution separation Al Cu Sn Fe Ni PNa 1N NaOH 0.029 0.0003 0.15 0.007 0.005 <0.005 0.002 6N NaOH 0.020 0.0003 0.15 0.007 0.005 <0.005 0.005 Sodium _{0.023 0.0003 0.15 0.007 0.005 <0.005 0.007} Ethoxide

(Example 5) In the same manner as in Example 1, 30 ml of a 6N sodium hydroxide solution was added to the cleaned electrode group.
The same operation as in Example 4 was performed except that the positive electrode current collector was dissolved. The results are shown in Tables 5 to 7 above.

(Example 6) In the same manner as in Example 1, 50 ml of methyl isobutyl ketone (MIBK) was added to the cleaned electrode group, and the mixture was allowed to stand for 10 minutes using an ultrasonic cleaner (45 kHz). (Al foil) and negative electrode current collector (Cu
The active material is peeled from the foil. 5m made of polypropylene
After filtration and washing with an m-mesh sieve, the residue (Al foil, Cu foil) on the sieve is dried and its weight is measured. Furthermore,
Al foil is dissolved by adding 50 ml of hydrochloric acid, and Cu foil is
After dissolving with 0 ml, each was transferred to a 1000 ml volumetric flask, and after constant volume, Fe, Ni, Cu, Co, Sn, and P were measured from the Al foil solution by ICP emission spectroscopy, and Li was measured by atomic absorption method. From the Cu foil solution, Fe, Ni, Al, Co, Sn, and P were measured by ICP emission spectroscopy, and Li was measured by atomic absorption spectrometry, and the impurity amount, purity, and recovery were calculated, respectively. Table 8 shows the results.

[0061]

Table 8 Table 7 Conditions for stripping impurities (g / one battery) in positive and negative electrode current collectors by MIBK separation Al Cu Sn Fe Ni Co P Li positive electrode current collector <0.0002 <0.0005 <0.0002 <0.0002 <0.0002 <0.005 <0.0002 Negative electrode collector 0.0004 <0.0005 <0.0003 <0.0002 <0.0002 <0.005 <0.0002

(Example 7) The same operation as in Example 4 was performed except that the positive electrode current collector was dissolved by adding 30 ml of a sodium ethoxide solution to the electrode group after the cleaning in the same manner as in Example 1. . The results are shown in Tables 5 to 7 above.

(Embodiment 8) After separating the electrode group in the same manner as in Embodiment 1, the positive electrode and the negative electrode are subjected to a heat treatment for 1 hour in a nitrogen gas recirculation type electric furnace previously adjusted to 250 ° C. The same operation as in Example 1 was performed except that the positive electrode and the negative electrode were put in a glass beaker, 200 ml of water was added, the mixture was stirred at 100 rpm using a magnetic stirrer, and the electrode material was separated from the positive electrode current collector. The results are shown in Tables 2 and 3 above.

Example 9 Example 8 was repeated except that the electrode group was separated in the same manner as in Example 1, and the positive electrode was subjected to a heat treatment for 1 hour in a nitrogen gas recirculation type electric furnace previously adjusted to 400 ° C. The same operation as described above was performed. The results are shown in Tables 2 and 3 above.

Example 10 Positive electrode material solution obtained in Example 3 (After immersing the positive electrode in 6N nitric acid, the filtrate obtained by filtration and the positive electrode active material in the positive electrode material were dissolved with hydrochloric acid, and the solution was filtered. The solution obtained by mixing the filtrates obtained above is transferred to a polyethylene beaker, and pure water is added to bring the total volume to 2000 ml. Further, 70 ml of hydrofluoric acid is added, and the mixture is poured into a polyethylene column containing 80 ml of a cation exchange resin (100 to 200 mesh).

After the solution has flowed out of the column, 100 ml of 1 N hydrofluoric acid is passed.

Next, after repeating this operation three times,
100 ml of 2N hydrochloric acid is passed through the column.

Next, after repeating this operation three times, 100 ml of 8N hydrochloric acid is passed through the column.

Next, this operation is repeated four times to cause cobalt ions to flow out of the column.

The cobalt solution that has flowed out is added with 2 m of 18N sulfuric acid.
After heating and evaporating at 120 ° C., about 1000
Heat at 1 ° C. for 1 hour to obtain cobalt oxide.

The weight of the obtained cobalt oxide was measured, and the recovery of cobalt was calculated.

Further, the obtained cobalt oxide is dissolved in hydrochloric acid, diluted with water, and made to a constant volume. Then, iron, tin, nickel, copper,
ICP (inductively coupled plasma) for aluminum ion concentration
By emission spectroscopy, the lithium ion concentration was measured by an atomic absorption method, and the amount of impurities contained in the cobalt oxide was calculated. Table 9 shows the results of the recovery rate of cobalt and the amount of impurities.

[0073]

Table 9 Cobalt recovery and impurity (g / battery) recovery after purification by ion exchange separation Al Cu Sn Fe Ni Li (%) Cation exchange separation <0.0002 <0.0002 <0.0005 <0.0002 0.002 < 0.005 98.3 Anion exchange separation <0.0002 <0.0002 0.16 0.0002 <0.0002 <0.005 98.0 Cation / anion _{<0.0002 <0.0002 <0.0005 <0.0002 <0.0002 <0.005 99.0} Exchange separation

(Example 11) A solution of the positive electrode material obtained in Example 3 (after immersing the positive electrode in 6N nitric acid, the filtrate obtained by filtration and the positive electrode active material in the positive electrode material were dissolved with hydrochloric acid, and the solution was filtered. The solution obtained by mixing the filtrates obtained above is transferred to a polyethylene beaker, and hydrochloric acid is added to adjust the acid concentration to 8N.

This solution was treated with an anion exchange resin (100 to 2).
00mesh) Pour into a polyethylene column containing 80 ml. After the solution flows out of the column, 100 ml of 9N hydrochloric acid is passed through the column.

Next, after repeating this operation three times, 100 ml of 1N hydrochloric acid is passed through the column.

Next, this operation is repeated four times to cause cobalt ions to flow out of the column.

The cobalt solution that has flowed out is added with 2 m of 18N sulfuric acid.
After heating and evaporating at 120 ° C., about 1000
Heat at 1 ° C. for 1 hour to obtain cobalt oxide. The weight of the obtained cobalt oxide was measured, and the recovery rate of cobalt was calculated.

Further, the obtained cobalt oxide is dissolved in hydrochloric acid, diluted with water, and the volume is adjusted. Then, iron, tin, nickel, copper,
ICP (inductively coupled plasma) for aluminum ion concentration
Lithium and sodium ion concentrations were measured by atomic absorption spectrometry by emission spectroscopy, and the amount of impurities contained in cobalt oxide was calculated. Table 9 shows the results of the recovery rate of cobalt, the amount of impurities, and the purity.

(Example 12) According to Example 10, after performing cation exchange separation, the cobalt solution flowing out was
Further, the anion exchange separation of Example 11 is performed.

The cobalt solution that had flowed out was subjected to the same operation as in Example 10 to recover cobalt oxide, and the recovery rate was calculated. Further, the content of impurities in cobalt oxide was calculated by performing the same operation. The results are shown in Table 9 above.

According to the results of the above examples, the present invention separates the positive electrode current collector (Al foil), the negative electrode current collector (Cu foil) and the positive electrode active material (LiCoO ₂ ) so that the separation operation alone is possible. Sufficiently high purity can be recovered. Therefore, by performing a simple chemical treatment after the separation, a valuable material having a purity of 99.9% or more can be easily obtained, which is considered to be a very effective method.

[0083]

As described above, according to the present invention,
The electrode material and the current collector can be easily separated by immersing the electrode in the lithium ion secondary battery in any of an acidic solution, an alkali metal hydroxide solution, an alkali metal alcohol solution or an organic solvent. After that, after immersing in an acidic solution to dissolve valuable metals, it can be recovered at low cost and high purity by chemical treatment. Therefore, its industrial value is very high.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a general cylindrical lithium ion secondary battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Insulator 3 Electrode group 4 Positive electrode 5 Separator 6 Negative electrode 7 Insulating paper 8 Insulating sealing plate 9 Positive electrode terminal 10 Positive electrode lead

Continued on the front page. (72) Inventor Yuki Tomioka 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Inventor Naohiko Chisato 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Inside Yokohama Office (72) Inventor Koide Izumi Komatsu 8th Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Inside (72) Inventor Hideo Kitamura 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Yokohama Business Co., Ltd. In-house (72) Inventor Takeshi Gotanda 8th Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Inventor Yoshihiro Chunai 8-8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Yokohama Business Co., Ltd. (72) Inventor Tomiaki Furuya 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Inventor Masaaki Morita 1st, Komukai-Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Research Consulting Co., Ltd. In company

Claims (5)

[Claims] An electrode of a lithium ion secondary battery is immersed in one of an acid solution, an alkali metal hydroxide solution, an alkali metal alcohol solution or an organic solvent, and the electrode is made of an electrode material and a current collector. A method for separating valuables from a lithium ion secondary battery, comprising at least a step of separating the valuables from the lithium ion secondary battery. 2. The lithium according to claim 1, wherein at least one of hydrohalic acid, sulfuric acid, aqueous hydrogen peroxide, acetic acid, nitric acid, fuming nitric acid, and perchloric acid is used as the acidic solution. A method for separating valuables from an ion secondary battery. 3. The lithium according to claim 1, wherein at least one of sodium hydroxide, potassium hydroxide and lithium hydroxide is used in the form of an aqueous solution or a molten state as the alkali metal hydroxide solution. A method for separating valuables from an ion secondary battery. 4. The method according to claim 1, wherein at least one of lithium alkoxide, sodium alkoxide and potassium alkoxide is used as the alkali metal alcohol solution. 5. The valuable resource from the lithium ion secondary battery according to claim 1, wherein at least one of ketone, ester, ether, alcohol, acetonitrile and aliphatic hydrocarbon is used as the organic solvent. Object separation method.