WO2021201151A1

WO2021201151A1 - Method for deactivating lithium ion secondary battery

Info

Publication number: WO2021201151A1
Application number: PCT/JP2021/013974
Authority: WO
Inventors: 哲也宇田; 勇樹谷ノ内; 章宏岸本
Original assignee: 国立大学法人京都大学
Priority date: 2020-03-31
Filing date: 2021-03-31
Publication date: 2021-10-07
Also published as: JPWO2021201151A1

Abstract

A method for deactivating a lithium ion secondary battery, the method comprising (A) a step for opening the lithium ion secondary battery in an alkali water solution or (B) a step for opening the lithium ion secondary battery in water under an inert gas atmosphere or a reductive gas atmosphere. By using said method, it is possible to easily and safely deactivate waste lithium ion secondary batteries.

Description

How to deactivate a lithium-ion secondary battery

The present invention relates to a method for deactivating a lithium ion secondary battery.

In modern society, the demand for lithium-ion secondary batteries is increasing, and the importance of efficient recycling of used lithium-ion secondary batteries (waste lithium-ion secondary batteries) is also increasing. However, lithium-ion secondary batteries contain highly reactive lithium (Li), and it has been reported that they ignite due to improper handling. In the past, hydrogen explosions have also occurred when processing waste lithium-ion secondary batteries in the United States. For this reason, "safe deactivation and dismantling" has become an issue, especially for large lithium-ion secondary batteries used in electric vehicles and the like. At present, it is assumed that waste lithium-ion secondary batteries are incinerated at high temperatures or treated with high-temperature steam, but harmful gases generated by combustion, decomposition, evaporation, etc. of organic solvents in lithium-ion secondary batteries. Large-scale processing equipment is required to detoxify the battery. In addition, treatment plants equipped with such large facilities are far from urban areas, and when transporting large waste lithium-ion secondary batteries to the treatment plant, they are transported in special containers to ensure safety. There is a need to.

Under such circumstances, as a method of deactivating the waste lithium ion secondary battery for recycling, for example, Patent Document 1 describes that the waste lithium ion secondary battery is incinerated after being discharged. There is. Further, Patent Document 2 describes that a lithium ion secondary battery is mechanically dry-pulverized in an atmosphere of argon, carbon dioxide or the like.

U.S. Patent Application Publication No. 2005/0235775 Special Table 2007-531977 Japanese Unexamined Patent Publication No. 6-141805 International Publication No. 2017/006209

At present, as in Patent Document 1, many studies have been conducted on the premise that lithium is inactivated by high-temperature incineration, but in this case, high-temperature incineration equipment is required, and a large-scale processing equipment is required. This is unavoidably unsuitable for distributed treatment in urban areas, and also poses a problem of detoxifying harmful fluorine-containing gas generated by combustion of an organic solvent contained in an electrolytic solution of a lithium ion secondary battery. Further, in the method of Patent Document 1, lithium and graphite are distributed in the slag phase and cannot be recovered. On the other hand, the method of Patent Document 2 is a very dangerous method because the waste lithium ion secondary battery violently ignites and generates heat by dry pulverization even in an atmosphere of argon, carbon dioxide, etc. It cannot be applied to the deactivation treatment of lithium-ion secondary batteries. Therefore, in order to prevent heat generation and generation of harmful gas, in Patent Document 3, the lithium ion secondary battery is cut or crushed in a liquid of water, alcohol, or acid or in an inert gas, and in Patent Document 4, shredder crushed in water. A method has been developed to do this. However, when the lithium ion secondary battery is cut in water and acid without controlling the atmosphere, gas is generated by hydrolysis of an organic solvent such as carbonate contained in the electrolytic solution, and the liquid is stored after deactivation. There is a danger in transportation.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a method for easily and safely inactivating a waste lithium ion secondary battery.

As a result of diligent studies to solve the above problems, the present inventors have opened a lithium ion secondary battery in an alkaline aqueous solution, or lithium ions in water under an inert gas atmosphere or a reducing gas atmosphere. It has been found that the waste lithium ion secondary battery can be easily and safely deactivated by opening the secondary battery. Based on these findings, the present inventors further studied and completed the present invention. That is, the present invention includes the following aspects.

Item 1. A method of deactivating a lithium-ion secondary battery,
(A) A step of opening the lithium ion secondary battery in an alkaline aqueous solution, or (B) a step of opening the lithium ion secondary battery in water under an inert gas atmosphere or a reducing gas atmosphere. How to prepare.

Item 2. Item 2. The method according to Item 1, wherein the amount of the alkaline aqueous solution used in the step (A) and the amount of water used in the step (B) is 10 mL or more with respect to the capacity of 1 Wh of the lithium ion secondary battery.

Item 3. Item 2. The method according to

Item

1 or 2, wherein the step (A) is carried out in an inert gas atmosphere or a reducing gas atmosphere.

Item 4. Item 6. The method according to any one of Items 1 to 3, wherein the pH of the alkaline aqueous solution in the step (A) is 10 to 14, and the pH of the water in the step (B) is 6 to 14.

Item 5. Item 1. The alkaline compound used as the alkaline aqueous solution is at least one selected from the group consisting of calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, sodium hydroxide, potassium hydroxide and lithium hydroxide. The method according to any one of 4 to 4.

Item 6. Item 6. The method according to any one of Items 1 to 5, wherein in the step (A), the alkaline aqueous solution is lime water.

Item 7. Item 6. The method according to any one of Items 1 to 6, wherein the content of the alkaline compound in the alkaline aqueous solution is larger than the saturation concentration.

Item 8. The step of opening the lithium ion secondary battery is to crush or cut the lithium ion secondary battery, to make a hole penetrating the casing of the lithium ion secondary battery, or to make a casing of the lithium ion secondary battery. Item 2. The method according to any one of Items 1 to 7, which is a step of opening a part or all of the above.

Item 9. Item 6. The method according to any one of Items 1 to 8, wherein the steps (A) and (B) are carried out at 10 to 80 ° C.

Item 10. Item 6. The method according to any one of Items 1 to 9, wherein the timing of completion of deactivation is determined from the state of generation of air bubbles from the opening.

Item 11. It is a method of visualizing the deactivation status of lithium-ion secondary batteries.
(A) A step of opening the lithium ion secondary battery in an alkaline aqueous solution, or (B) a step of opening the lithium ion secondary battery in water under an inert gas atmosphere or a reducing gas atmosphere. A method of visualizing the deactivation status of a lithium-ion secondary battery by generating air bubbles from the opening.

Item 12. It is a method of separating and recovering metal elements from a lithium ion secondary battery.
A method comprising a step of deactivating a lithium ion secondary battery by the method according to any one of Items 1 to 11 and then crushing and physically sorting the deactivated lithium ion secondary battery. ..

Item 13. Item 12. The method according to Item 12, wherein at least one selected from the group consisting of lithium, nickel and cobalt is recovered as a solid oxide, and copper and / or aluminum is recovered as a metal.

Item 14. (A1) A step of sorting a casing with a control substrate by size from the inactivated solid matter of a lithium ion secondary battery and recovering aluminum.
(A2)

Item

12 or 13 comprising a step of recovering at least one selected from the group consisting of copper scraps, aluminum scraps and separator pieces by sieving (1) from the solid matter remaining in the step (A1). The method described in.

Item 15. After the step (A2)
(A3) A step of recovering a separator piece by sieving (2) from the solid matter remaining in the step (A2), and (A4) Copper scrap and aluminum scrap from the solid matter remaining in the step (A3). Item 14. The method according to Item 14, further comprising a step of separating.

Item 16. After the step (A2)
(B3) The suspension of the deactivated lithium ion secondary battery is filtered, and at least selected from the group consisting of oxides of lithium, cobalt, nickel and manganese, graphite powder, aluminum hydroxide and calcium fluoride. Item 12. The method according to Item 14, further comprising a step of separating one type.

Item 17. A lithium ion secondary battery deactivating device used to deactivate a lithium ion secondary battery in an alkaline aqueous solution or water.
A chamber in which an alkaline aqueous solution or water is stored, and
A lithium ion secondary battery deactivating device that is arranged in the chamber and includes a mechanism for opening the lithium ion secondary battery charged into the chamber.

Item 18. An openable and closable lid that is placed on the chamber and is formed on the alkaline aqueous solution or water to isolate the closed space from the outside.
Item 12. The lithium ion secondary battery deactivating apparatus according to Item 17, further comprising a gas supply unit that supplies an inert gas or a reducing gas to the closed space.

Item 19. A vehicle comprising the lithium ion secondary battery deactivating device according to item 17 or 18.

Item 20. A lithium ion secondary battery recycling method using the method according to any one of Items 1 to 11.

According to the present invention, the waste lithium ion secondary battery can be easily and safely deactivated. Therefore, the deactivated product can be transported easily and safely, and the recycling of the waste lithium ion secondary battery can be promoted.

The configuration of a general small lithium-ion secondary battery and the raw material price of each member are shown. An example of a method for separating and recovering a metal element from a lithium ion secondary battery is shown. An example of a vehicle in which waste lithium ion secondary batteries can be deactivated on-site (automobile dismantling factory, accident site, etc.) and separated and recovered for each element is shown. The schematic diagram of the lithium ion secondary battery deactivation apparatus of this invention is shown. (A) Exterior photograph. (B) Plan view. (C) Cross-sectional view. It is a photograph explaining the meaning of "no pretreatment", "opening" and "cutting" in this embodiment. In Comparative Example 3, the result when the lithium ion secondary battery is cut by the dry type is shown. In Example 2, the result when the lithium ion secondary battery was opened in lime water is shown. In Test Example 1, the result of analyzing the oxygen concentration and the hydrogen concentration during the deactivation treatment by using gas chromatography (GC) is shown. In Test Example 1, a flowchart of the deactivation treatment and the element separation treatment of the lithium ion secondary battery is shown. The state of the separated sample is also shown. In Test Example 1, a flowchart of the deactivation treatment and the element separation treatment of the lithium ion secondary battery is shown. The recovery rate of the separated samples is also shown. In Test Example 2, the ultraviolet-visible absorption spectrum when ethylene carbonate is added to deionized water is shown. In Test Example 3, the corrosion behavior of iron balls in lime water, hydrofluoric acid and NaCl aqueous solution is shown.

In this specification, when the numerical range is indicated by "A to B", it means A or more and B or less. In addition, "contains" includes any of "comprise", "consist essentially of", and "consist of".

1. 1. Method for Inactivating a Lithium Ion Secondary Battery First, FIG. 1 shows the configuration of a general small lithium ion secondary battery and the raw material price of each member. When the resin exterior is removed from a general lithium-ion secondary battery, a casing made of aluminum or the like and having a control substrate appears. This includes a positive electrode active material, a positive electrode current collector (aluminum foil), a negative electrode active material, a negative electrode current collector (copper foil), an electrolytic solution, a separator, an insulating film and the like. Comparing the raw material prices of each member, the positive electrode active material accounts for about 79% of the total, and all of them contain lithium. That is, considering the recycling efficiency from the lithium ion secondary battery, it is preferable to recover lithium, and it is more preferable to recover the metal elements in the positive electrode active material, particularly nickel and cobalt.

On the other hand, in the conventional method of deactivating a lithium ion secondary battery, many studies have been conducted on the premise that lithium is deactivated by high temperature incineration as in Patent Document 1. In this case, high-temperature incineration equipment is required, and it is inevitable that a large-scale processing equipment is required, which is not suitable for distributed processing in urban areas, and an organic solvent contained in the electrolyte of a lithium ion secondary battery. It is necessary to detoxify the harmful fluorine-containing gas generated by the combustion of.

In the method of deactivating lithium by high-temperature incineration as in Patent Document 1, the lithium-ion secondary battery is heated and melted in a high-temperature furnace, and valuable resources are dissolved in the molten alloy. After that, the alloy is leached with acid and each element is separated by solvent extraction. However, in the method of Patent Document 1, lithium and graphite are distributed in the slag phase and cannot be recovered. For this reason, the lithium contained in the lithium ion secondary battery has not been recovered. That is, the conventional method of deactivating a conventional lithium ion secondary battery cannot be said to be an efficient recycling method.

On the other hand, the method of deactivating the lithium ion secondary battery of the present invention is
(A) A step of opening the lithium ion secondary battery in an alkaline aqueous solution, or (B) a step of opening the lithium ion secondary battery in water under an inert gas atmosphere or a reducing gas atmosphere. Be prepared.

As described above, in the method of deactivating the lithium ion secondary battery of the present invention, the lithium ion secondary battery is opened in neutral or alkaline water or an aqueous solution to form the lithium ion secondary battery. It is possible to gently inactivate the lithium contained. Moreover, in the method of deactivating the lithium ion secondary battery of the present invention, lithium, nickel and cobalt can be recovered as solid oxides, and copper and aluminum can be recovered as metals. Is also useful.

The method of deactivating the lithium ion secondary battery of the present invention does not generate toxic gas, can be carried out in a relatively small facility, and can safely disassemble the lithium ion secondary battery. be.

Therefore, the lithium ion secondary battery can be easily and safely disassembled in various places in urban areas such as automobile dismantling sites, and the lithium ion secondary battery can be easily and safely disassembled and transported. be.

(1-1) Alkaline aqueous solution and water In the step (A), the lithium ion secondary battery is opened in the alkaline aqueous solution. Further, in the step (B), the lithium ion secondary battery is opened in water under an inert gas atmosphere or a reducing gas atmosphere.

The alkaline compound used as the alkaline aqueous solution in the step (A) is not particularly limited as long as it is a compound that exhibits alkalinity (particularly about pH 10 to 14) when dissolved in water, and is, for example, calcium hydroxide, calcium oxide, or water. Examples thereof include magnesium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide and lithium hydroxide. These alkaline compounds may be used alone or in combination of two or more.

When the alkaline aqueous solution is adopted in the step (A), if the content of the alkaline compound in the alkaline aqueous solution is not more than the saturation concentration, the alkaline compound is consumed by the reaction during the deactivation treatment of the lithium ion secondary battery. Specifically, it will be described in detail below.

For example, when the carbonate in the lithium ion secondary battery is ethylene carbonate, the carbonate is hydrolyzed in water, causing the following reaction.

Since the carbon dioxide generated at this time reacts with the alkaline compound and precipitates, the hydrolysis of the carbonate in the above formula is promoted. For example, when the alkaline compound is calcium hydroxide, it reacts with carbon dioxide to form calcium carbonate as follows.

In addition to the above-mentioned decomposition reaction of carbonate, the alkaline compound is also consumed in the decomposition reaction _{of LiPF 6 described later.} Therefore, when the content of the alkaline compound in the alkaline aqueous solution is set to the saturation concentration or less, the alkaline compound is consumed by the reaction during the deactivation treatment of the lithium ion secondary battery, and the decomposition reaction of _{carbonate and LiPF 6 proceeds.} It becomes difficult and may not be completely detoxified.

Therefore, in the step (A), it is preferable that a part of the alkaline compounds is precipitated so that the content of the alkaline compounds in the alkaline aqueous solution is larger than the saturation concentration. As a result, even if the alkaline compound is consumed by the reaction during the deactivation treatment of the lithium ion secondary battery, the precipitation can be dissolved in the alkaline aqueous solution to replenish the concentration of the alkaline compound.

For example, when calcium hydroxide is used as the alkaline compound, only 0.17 g of calcium hydroxide is dissolved in 100 mL of water at room temperature, but the amount of calcium hydroxide contained in the alkaline aqueous solution is regarded as an excess amount and is dissolved. It is preferable to add, for example, 0.17 to 100 g, particularly 0.4 to 10 g, with respect to 100 mL of water.

The pH of the alkaline aqueous solution used in the step (A) is not particularly limited, but 10 to 14 are set from the viewpoint of efficiency, safety, economy, etc. of the deactivation treatment of the lithium ion secondary battery. Preferably, 11 to 13 are more preferable.

The water used in the step (B) is not particularly limited, and various types of water such as distilled water, tap water, industrial water, ion-exchanged water, deionized water, pure water, and electrolyzed water can be used. The water used in the step (B) is preferably neutral or alkaline (6 ≦ pH ≦ 14).

The amount of the alkaline aqueous solution used in the step (A) and the amount of water used in the step (B) is preferably excessive. Specifically, it will be described in detail below.

In the present invention, active lithium in a lithium ion secondary battery comes into contact with water and reacts preferentially, and gently deactivates while generating hydrogen. The reaction at this time is the reaction formula:
_{_{_{LiC x + yH 2 O → y}}} / 2H 2 + Li + + yOH - + xC
Proceed according to. At this time, the flammable organic solvent contained in the electrolytic solution of the lithium ion secondary battery is dissolved in water and diluted, and the oxygen concentration is constant before and after the reaction, that is, oxygen is not generated by the reaction. Since the alkaline aqueous solution or water also functions as a coolant for preventing a rapid temperature rise, ignition and heat generation can be suppressed, which is a safe method. In addition, the excess water in the reaction water (H 2 _O) nor insufficient.

In this reaction, hydroxide ions are generated, but since they are _{consumed in the decomposition reaction of carbonate and LiPF 6} described later, the pH is maintained in an appropriate range in the neutral or alkaline region and inactivated. It is possible to continue the process.

From the above, the amount of the alkaline aqueous solution used in the step (A) and the amount of water used in the step (B) is preferably excessive, and 10 mL or more is used with respect to the capacity of the target lithium ion secondary battery of 1 Wh. Preferably, 70 mL or more is more preferable, and 130 mL or more is further preferable. The larger the amount of the alkaline aqueous solution used in the step (A) and the amount of water used in the step (B), the better, and the upper limit is not particularly limited. It is not preferable to use water. Therefore, the alkaline aqueous solution or water is preferably 1000 mL or less with respect to the capacity of the target lithium ion secondary battery of 1 Wh. Usually, it is about 50 to 500 mL with respect to a capacity of 1 Wh of the target lithium ion secondary battery.

As described above, in the method for deactivating the lithium ion secondary battery of the present invention, the lithium ion secondary battery is opened by opening the lithium ion secondary battery in neutral or alkaline water or an aqueous solution, thereby forming the lithium ion secondary battery. It is possible to gently inactivate the lithium contained in.

In particular, in the method of inactivating the lithium ion secondary battery of the present invention, when the step (A), that is, the alkaline aqueous solution is adopted, the hydrolysis of the organic solvent such as carbonate is fast as described below. It is possible to shorten the time for gas generation.

In the aqueous solution, carbonates and the like contained as an organic solvent in the electrolytic solution existing in the lithium ion secondary battery are hydrolyzed to gradually generate carbon dioxide. As for the expected decomposition reaction at this time, for example, when the carbonate is ethylene carbonate, the following reaction formula is assumed.

In the method of deactivating the lithium ion secondary battery of the present invention, step (A), that is, when an alkaline aqueous solution is adopted, the reaction is shortened and the generated carbon dioxide is reacted with the alkaline aqueous solution. Since it is easy to capture (when lime water is used as the alkaline aqueous solution, it is easy to immobilize it as calcium carbonate), it is also useful in that the exhaust time can be further shortened.

_{Further, in the aqueous solution, LiPF 6} contained as an electrolyte salt of the electrolytic solution existing in the lithium ion secondary battery is eluted in the treatment liquid during the deactivation treatment of the lithium ion secondary battery. At this time, LiPF ₆ is easily hydrolyzed while producing HF.

In the method of deactivating the lithium ion secondary battery of the present invention, when the step (A), that is, the alkaline aqueous solution is adopted, harmful fluoride ions are easily immobilized as salts. For example, when lime water is used as the alkaline aqueous solution, fluoride ions can be _{easily immobilized as calcium fluoride (CaF 2} ) on the spot, and the step of separating fluoride ions can be omitted.

In the step (B), that is, when water is used, it is preferable to use an alkaline aqueous solution in a later step in order to remove the fluoride ions generated. Therefore, even when the step (B), that is, water is adopted, it is preferable to use the alkaline aqueous solution in combination. Therefore, it is preferable to adopt the step (A), that is, the alkaline aqueous solution from the beginning.

Further, in the method of deactivating the lithium ion secondary battery of the present invention, the step (A), that is, when the alkaline aqueous solution is adopted, the iron-based material is not rusted, so that the lithium ion secondary battery is not used. In the deactivation treatment facility, etc., it is possible to use an inexpensive iron-based material even for the members that come into contact with the treatment liquid, and the range of material selection is widened.

(1-2) Atmosphere When the step (A), that is, the alkaline aqueous solution is adopted as the method for deactivating the lithium ion secondary battery of the present invention, the atmosphere is not particularly limited. Of these, an inert gas atmosphere such as a nitrogen gas atmosphere and an argon gas atmosphere, and a reducing gas atmosphere such as a hydrogen gas atmosphere are preferable.

On the other hand, as a method for deactivating the lithium ion secondary battery of the present invention, the step (B), that is, when water is adopted, is under an inert atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere, or hydrogen. Adopt a reducing gas atmosphere such as a gas atmosphere.

When such an atmosphere is adopted, since oxygen does not exist in the atmosphere, the hydrogen generated during the deactivation treatment of the lithium ion secondary battery becomes chemically stable, and the lithium ion secondary battery becomes It is easier to further suppress the risk of ignition and heat generation.

(1-3) Temperature The temperature at which the method for deactivating the lithium ion secondary battery of the present invention is carried out is not particularly limited, and for example, it can be carried out at room temperature. That is, unlike the conventional method, high temperature incinerator is not required, and a simpler and safer method can be used. Specifically, the temperature at which the method for deactivating the lithium ion secondary battery of the present invention is carried out can be, for example, 10 to 80 ° C, preferably 15 to 45 ° C.

(1-4) Opening Treatment In the method for deactivating the lithium ion secondary battery of the present invention, the opening treatment of the lithium ion secondary battery is not particularly limited, and various various methods can be adopted. Specifically, crushing or cutting a lithium ion secondary battery, making a hole through the casing of the lithium ion secondary battery, or opening a part or all of the casing of the lithium ion secondary battery. Can be mentioned. In addition, "crushing the lithium ion secondary battery" means breaking and crushing the lithium ion battery. Further, "crushing or cutting a lithium ion secondary battery" does not mean only crushing or cutting only the casing of a lithium ion secondary battery to expose the inside. "Crushing or cutting a lithium ion secondary battery" means crushing or cutting an unspecified position of a lithium ion secondary battery to crush or cut a storage part such as a current collector and a separator arranged in a casing. Or it also means cutting.

Further, in the present invention, the number of times the lithium ion secondary battery is crushed or cut is not particularly limited as long as it is once or more, but it is preferably a plurality of times. Further, when the lithium ion secondary battery is crushed or cut a plurality of times, it is preferable to crush or cut the lithium ion secondary batteries at different positions. As a result, it is possible to achieve rapid deactivation and to rapidly proceed with processes such as physical sorting in the process after deactivation.

In this case, according to the method of cutting a part or all of the casing of the lithium ion secondary battery, among the methods of deactivating the lithium ion secondary battery of the present invention, the lithium ion secondary of the present invention is particularly safe. The battery can be deactivated.

Further, according to the method of crushing or cutting the lithium ion secondary battery or making a hole penetrating the casing of the lithium ion secondary battery, among the methods of deactivating the lithium ion secondary battery of the present invention. , The deactivation time can be shortened in particular. According to the conventional dry method of deactivating in air, if a method of crushing or cutting the lithium ion secondary battery or making a hole penetrating the casing of the lithium ion secondary battery is adopted, The lithium ion secondary battery ignites or generates heat. However, if the method for deactivating the lithium ion secondary battery of the present invention is adopted, the lithium ion secondary battery can be crushed or cut, or the lithium ion secondary battery can be crushed or cut. The lithium-ion secondary battery can be safely deactivated by making a hole through the casing of the battery.

(1-5) Immersion treatment After the lithium ion secondary battery is opened as described above, the active lithium in the lithium ion secondary battery comes into contact with water and reacts preferentially. It gently deactivates while generating hydrogen. The reaction at this time is the reaction formula:
_{_{_{LiC x + yH 2 O → y}}} / 2H 2 + Li + + yOH - + xC
Proceed according to. At this time, the flammable organic solvent contained in the electrolytic solution of the lithium ion secondary battery is dissolved in water and diluted, and the oxygen concentration is constant before and after the reaction, that is, oxygen is not generated by the reaction. Since the alkaline aqueous solution or water also functions as a coolant for preventing a rapid temperature rise, ignition and heat generation can be suppressed, which is a safe method.

If the above reaction does not proceed, that is, if hydrogen is no longer generated, it can be determined that the deactivation treatment of the lithium ion secondary battery has been completed. , It can be determined that the deactivation treatment of the lithium ion secondary battery is completed. Therefore, according to the present invention, it is possible to visualize the deactivation progress status of the lithium ion secondary battery based on the bubble generation rate (generation status). Therefore, safer and more efficient processing can be realized as compared with the conventional processing method.

From the viewpoint of ensuring safety, it is preferable that deactivation is completed when the generation of bubbles is completely stopped. However, from the viewpoint of work efficiency, the deactivation may be completed when the bubble generation rate becomes equal to or lower than a predetermined standard. Here, optical means, quantitative means, and the like can be adopted in determining the standard. As long as it is an optical means, for example, it may be measured by a spectroscopic device, or may be photographed or visually observed. If it is a measuring means, for example, the volume of bubbles generated within a predetermined time may be measured by collecting the generated bubbles.

It is also possible to recover the generated hydrogen.

From the above, after opening the lithium ion secondary battery, it is preferable to immerse it in an alkaline aqueous solution or water until no bubbles are visually generated. The specific immersion time can be, for example, 10 minutes to 24 hours, particularly 30 minutes to 6 hours.

2. Method of separating and recovering metal elements from a lithium ion secondary battery The method of deactivating the lithium ion secondary battery of the present invention does not generate toxic gas and can be performed in a relatively small facility, which is safe. It is possible to disassemble the lithium-ion secondary battery.

Therefore, it is possible to easily and safely deactivate the lithium-ion secondary battery in various places in urban areas such as automobile dismantling sites and at the accident site of a self-propelled vehicle, and the lithium-ion secondary battery can be easily and safely deactivated. It can be disassembled and transported, from which each element can be separated and recovered. An example of this separation / recovery method is shown in FIG.

The lithium ion secondary battery or its crushed product safely deactivated in this way contains metal elements such as lithium, aluminum, copper, nickel, cobalt, and manganese, and is physically sorted or chemically selected. It is possible to separate and collect each of them by various treatments.

In the method for deactivating a lithium ion secondary battery of the present invention, for example, a hole is formed through the casing of the lithium ion secondary battery, or a part or all of the casing of the lithium ion secondary battery is opened. If so, it is preferable to reduce the particle size of the object in order to facilitate the subsequent treatment. Note that FIG. 2 shows an example in which the lithium ion secondary battery is deactivated by the cutting treatment using the attritor shown in FIG.

Specifically, the casing with the control board can be sorted by size from the deactivated solids. From here it is possible to recover a lot of aluminum. Then, it can be cut into a desired size (20 mm × 20 mm in FIG. 2), and then crushed by a ball mill or the like using an iron ball or the like.

After that, it is possible to collect copper scraps, aluminum scraps, separator pieces, iron balls used in the ball mill, etc. by sieving (1) having an opening of about 0.5 to 3 mm (1 mm in FIG. 2), for example. Iron balls can be recovered by magnetically sorting from this mixture, and separator pieces can be recovered by sieving (2) having a mesh size of about 5 to 15 mm (10 mm in FIG. 2). The balance is a mixture of copper scraps and aluminum scraps, which can be separated by physical sorting such as eddy current sorting and shipped to an existing treatment plant.

On the other hand, oxides such as lithium, cobalt, nickel and manganese, graphite powder, aluminum hydroxide, calcium fluoride and the like can be separated by filtering the suspension after the above sieving (1). Can be done. These can be processed in medium-sized smelters specializing in waste lithium-ion secondary battery processed products or in existing smelters. From here, about 70% of lithium, nickel, cobalt and most of them can be recovered.

Most of the valuable elements can be recovered as a solid, and in particular, lithium, graphite, and the like, which are difficult to recover by the conventional dry treatment, are useful in that they can be concentrated and separated as a solid by the method of the present invention. .. Further, in the method of the present invention, since copper and aluminum can be recovered as metals, chemical treatment such as acid leaching and reduction is not required as in the conventional method, and the material can be easily recycled thereafter.

From the above, according to the method of deactivating the lithium ion secondary battery of the present invention, it is possible to realize a wet recycling process that is extremely small and has a high recovery rate of valuable resources as compared with the conventional dry process. be. Preferably, the transportation of large-sized waste lithium-ion secondary batteries to a centralized facility or a smelter can be transformed into a safe and convenient one. For example, the problem of transporting waste lithium-ion secondary batteries, which has been a bottleneck due to the deactivation treatment of lithium-ion secondary batteries at each treatment plant, by setting up treatment plants at dismantling sites of automobiles in various places. Can be solved.

Further, if a vehicle equipped with a lithium ion secondary battery deactivating device as shown in FIG. 3 is prepared, a waste lithium ion secondary battery such as a defective vehicle is placed in a chamber of a container soaked with an alkaline aqueous solution or water in advance. Then, the waste lithium ion secondary battery can be cut and crushed by a cutting and crushing unit (for example, a pair of rollers facing the cutting blade), and then each element can be separated from the crushed material.

Here, a lid is provided to cover the upper part of the container so that it can be opened and closed at the part where the waste lithium ion secondary battery is inserted. When the upper part of the container is closed by the lid, the space formed on the alkaline aqueous solution or water is sealed with the lid, and a closed space isolated from the outside is formed. In this state, when an inert gas (nitrogen gas) is supplied from the gas supply unit (nitrogen generator) via the tube, the closed space is filled with the inert gas, and an inert gas atmosphere is formed. When a reducing gas (for example, hydrogen gas or the like) is supplied, the closed space is filled with the reducing gas, and it is possible to form a reducing gas atmosphere.

The vehicle is provided with a single sieve or a plurality of sieves having different mesh sizes, and the crushed material is separated by passing the crushed material together with the alkaline aqueous solution or water in the chamber. Is possible. When a plurality of sieves having different meshes are provided, it is possible to separate the crushed material according to the size. The alkaline aqueous solution or water from which the crushed material has been removed is supplied into the chamber again.

In addition, the vehicle is equipped with a compressor and a hydrogen storage tank in order to recover the hydrogen generated when lithium is deactivated. The compressor has a function of compressing hydrogen from a closed space and supplying it to a hydrogen storage tank. Further, the vehicle may be provided with a fuel cell that generates electricity using hydrogen.

That is, it is possible to perform from deactivation of the waste lithium ion secondary battery to recovery of each element in the vehicle shown in FIG. 3 without preparing a separate processing facility, and it is possible to perform the process from the deactivation of the waste lithium ion secondary battery to the recovery of each element. It can also be carried out at the site where the next battery is generated. After that, it can be transported to a dedicated treatment facility or smelter for recycling of various metal elements and waste liquid treatment of the treatment liquid. From the above, it is possible to realize an on-site type crude separation process with deactivation, and it can be used as a mobile primary smelter in various parts of the world including developing countries.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples.

In this embodiment, "no pretreatment" means that the casing is not damaged and the lithium ion secondary battery existing in the casing is not exposed, as shown in the left figure of FIG.

In this embodiment, as shown in the middle figure of FIG. 5, "opening" exists in the casing by cutting off only a part of the casing so as not to damage the lithium ion secondary battery existing in the casing. It means exposing the lithium-ion secondary battery.

In this embodiment, "cutting" means cutting the casing together with the lithium ion secondary battery existing in the casing, as shown in the right figure of FIG.

The lithium ion secondary battery (3 cm x 4 cm x 0.7 cm; nominal voltage 3.7 V; charging capacity 895 mAh; charged) was newly purchased and charged, and used as a sample.

Comparative Example 1: In a glove box with no underwater pretreatment and a nitrogen atmosphere (oxygen concentration: less than 1% by volume), the resin extrapolation of the lithium ion secondary battery was removed, and the deionized water was removed without cutting the casing. 250 mL of the treatment liquid was placed in an air collecting bottle, and the presence or absence of ignition and air bubbles when the lithium ion secondary battery was immersed was confirmed.

In this case, although it did not ignite, no bubbles were generated and the deactivation of the lithium ion secondary battery did not proceed at all.

Comparative Example 2: Calcium hydroxide in a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume) without pretreatment in lime water, with the resin extrapolation of the lithium ion secondary battery removed and the casing not excised. 250 mL (1 g of calcium hydroxide put into the treatment liquid) was put into an air collecting bottle as a treatment liquid in which lime water coexisting with the above was put, and the presence or absence of ignition and air bubbles when the lithium ion secondary battery was immersed was confirmed.

In this case, although it did not ignite, bubbles continued to be generated for about 3 days to 1 week, and the cell voltage of the battery dropped only to about 1V. From this, it took at least 3 days or more to discharge the lithium ion secondary battery, and moreover, it was not possible to completely deactivate the lithium ion secondary battery.

Comparative Example 3: Dry cutting In a glove box with a nitrogen atmosphere (oxygen concentration: less than 1% by volume), the resin extrapolation of the lithium ion secondary battery was removed, and the casing was cut by about 1 cm together with the internal lithium ion secondary battery. And confirmed the reactivity. That is, the same method as in Patent Document 2 was performed.

As a result, it was understood that it is a very dangerous method because when it is cut, it immediately emits a spark and the entire lithium ion secondary battery heats up violently, white smoke is generated, and the temperature becomes so high that the casing becomes red hot. The results are shown in FIG.

Example 1: Opened in water In a glove box with a nitrogen atmosphere (oxygen concentration: less than 1% by volume), the resin extrapolation of the lithium ion secondary battery is removed, and the internal lithium ion secondary battery is not damaged. As described above, a part of the casing (only the side surface) was excised, 250 mL of deionized water was put into an air collecting bottle as a treatment liquid, and the presence or absence of ignition and air bubbles was confirmed.

In this case, gas containing hydrogen gas was generated from the terminal and the inside of the cell, and deactivation proceeded. In addition, during the reaction, no bubbles were generated in about 16 hours without ignition. Therefore, it can be understood that the deactivation of the lithium ion secondary battery is completed in about 16 hours.

Example 2: Opened in lime water In a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume), the resin extrapolation of the lithium ion secondary battery is removed, and the internal lithium ion secondary battery is damaged. Part of the casing (only the side surface) was excised so that there was no such thing, and 250 mL of lime water in which calcium hydroxide (calcium hydroxide put into the treatment liquid was 1 g) was precipitated was put into an air collecting bottle as a treatment liquid, and ignited and fired. The presence or absence of air bubbles was confirmed.

In this case, gas containing hydrogen gas was generated from the terminal portion and the inside of the cell, and deactivation proceeded. Further, during the reaction, bubbles did not occur in about 9 hours without ignition, the cell voltage became 1 V or less, and dropped to 0 V in about 24 to 30 hours. Therefore, it can be understood that the deactivation of the lithium ion secondary battery is completed in about 9 hours. At the end of the reaction, aluminum, which is the material of the casing, was oxidized to form a white film, and the formation of LiAl ₂ (OH) ₇ (H ₂ O) ₂ and CaCO ₃ was confirmed. Therefore, it is suggested that the deactivation of the lithium ion secondary battery proceeded faster than in Example 1 by the opening and dipping treatment using lime water. The results are shown in FIG.

Example 3: Cutting in lime water In a glove box with a nitrogen atmosphere (oxygen concentration: less than 1% by volume), the resin extrapolation of the lithium ion secondary battery is removed, and the casing is about 1 cm together with the internal lithium ion secondary battery. 250 mL of lime water obtained by cutting and precipitating calcium hydroxide (1 g of calcium hydroxide added to the treatment liquid) was placed as a treatment liquid in an air collecting bottle, and the presence or absence of ignition and air bubbles was confirmed.

In this case, gas containing hydrogen gas was generated from the terminal and the inside of the cell, and deactivation proceeded. In addition, it can be understood that the deactivation of the lithium ion secondary battery is completed because bubbles are not generated in about 1 hour without ignition during the reaction.

Test Example 1: Deactivation treatment in lime water and deactivation behavior when the lithium ion secondary battery immersed in the element recovery aqueous solution was cut were investigated at 23 to 25 ° C. FIG. 2 shows a flowchart of the deactivation process of the lithium ion secondary battery. In a glove box with a nitrogen atmosphere (oxygen concentration: less than 1% by volume), the resin extrapolation of the lithium ion secondary battery was removed to expose the aluminum casing. 300 mL of lime water in which calcium hydroxide (calcium hydroxide charged into the treatment liquid is 1 g) is precipitated as a treatment liquid is filled in the chamber 1 of the lithium ion secondary battery cutting device (atherator) shown in FIG. 4 as a sample. The lithium ion secondary battery installed on the table 2 was immersed. After that, the apparatus was operated, and the lithium ion secondary battery was pressed against the stainless steel blade 3 installed in the chamber 1 with the rotary rod 4 to cut the lithium ion secondary battery. At this time, in order to operate more safely, the drop lid 5 was arranged in the chamber 1. When the lithium ion secondary battery could not be cut by one operation of the device, the device was repeatedly operated to cut the lithium ion secondary battery.

The cut lithium-ion secondary battery was left to stand in the treatment liquid until the generation of bubbles was completed, and gas was sampled as appropriate. The sampled gas was analyzed for oxygen concentration and hydrogen concentration by gas chromatography (manufactured by Shimadzu Corporation, GC-8A). The results are shown in FIG.

As a result, it was suggested that hydrogen gas was generated during the deactivation treatment, and that lithium in the negative electrode was deactivated by the reaction with water. In addition, the oxygen concentration was almost constant, suggesting that decomposition of the positive electrode active material and oxidation of water did not occur.

After the reaction was completed, the treatment liquid and the solid matter were carried out from the glove box into the atmosphere, and the solid matter was cut into a size of about 2 cm × 2 cm by removing the aluminum casing piece by hand. From the casing thus removed, it was possible to recover 86.7% of aluminum as metallic aluminum. Next, the cut solid matter was placed in a polypropylene bottle together with about 20 iron balls (average diameter 0.9 cm) and 100 mL of deionized water, and ball milled for 10 hours. The solid matter crushed in this way was separated by a sieve having a mesh size of 1 mm, and then the solid on the sieve was further separated by magnetic force sorting and sieving with a mesh size of 10 mm to separate iron balls, copper scraps / aluminum scraps, and separator pieces. .. Since a black suspension was collected under the sieve, the black powder and the transparent ball mill liquid were collected by filtering the suspension. A part of these recovered products was sampled and dissolved in a mixed solution of hydrochloric acid and hydrogen peroxide, and the metal elements contained in each were quantified by the ICP-AES method. The results are shown in FIGS. 9 and 10. As a result, it was possible to recover 69% of lithium metal, 99.2% of nickel, and 98.9% of cobalt as solid oxides, and 94.2% of copper as metallic copper.

Test Example 2: In the carbonate decomposition aqueous solution in the electrolytic solution, the carbonate contained as the organic solvent of the electrolytic solution existing in the lithium ion secondary battery is hydrolyzed to gradually generate carbon dioxide. Prolonged carbon dioxide generation raises concerns about the safety of storage and transportation of the treatment fluid. As for the expected decomposition reaction at this time, for example, when the carbonate is ethylene carbonate, the following reaction formula is assumed.

Therefore, 8.8 g of ethylene carbonate was added to 100 mL of each solution, and the behavior was compared.

FIG. 11 shows an ultraviolet-visible absorption spectrum when ethylene carbonate is added to deionized water. As a result, when the results after 1 hour, 18 hours and 36 hours were compared with the results after 3 months, the intensity of the absorption spectrum was slightly reduced. Therefore, in deionized water, it is suggested that the deactivation reaction of the lithium ion secondary battery is not completed even after 36 hours, and the reaction gradually progresses until 3 months later, resulting in decomposition of carbonate. It was suggested that it would take a long time.

On the contrary, when 100 mL of lime water obtained by precipitating calcium hydroxide (14 g of calcium hydroxide added to the treatment liquid) was used, the hydrolysis was completed in a short time of less than 1 hour, and the treatment liquid was stored and stored. It was suggested that it is advantageous in terms of transportation safety.

Test Example 3: Utilization of iron-based material in lime water treatment In order to examine the use of steel material for equipment materials such as reaction vessels in deactivation treatment of lithium ion secondary batteries in aqueous solution, in various solutions. The corrosion behavior of the iron sample was investigated.

Approximately 2 g of iron balls (average diameter 5 mm, SUJ-2) were placed in a polypropylene bottle, 100 mL of each aqueous solution was added, and the mixture was allowed to stand in the air. The aqueous solution used in this test example was lime water in which calcium hydroxide (10 g of calcium hydroxide was added to the treatment solution) was precipitated, 0.01 mM hydrofluoric acid, and 0.25 M NaCl aqueous solution. used. The NaCl aqueous solution was adopted because salt water is used for the discharge treatment of the lithium ion secondary battery. The results are shown in FIG. 12 and Table 1.

As a result, it was suggested that the iron-based material could not be used because the color changed after 1 day in the hydrofluoric acid and the aqueous solution of NaCl. On the other hand, with lime water, there was no change even after 2 months had passed. Since there was no change even in the atmosphere in the presence of oxygen, it is suggested that there is no change in the case of adopting the inert atmosphere or the reducing atmosphere as well. Therefore, in the method for deactivating a lithium ion secondary battery of the present invention, it is suggested that an iron-based material such as a steel material can be used as a device material such as a reaction vessel, and the range of material selection is widened. ..

1 Chamber 2 Sample stand 3 Blade 4 Rotating rod 5 Otoshi buta

Claims

A method of deactivating a lithium-ion secondary battery,
(A) A step of opening the lithium ion secondary battery in an alkaline aqueous solution, or (B) a step of opening the lithium ion secondary battery in water under an inert gas atmosphere or a reducing gas atmosphere. How to prepare.
The method according to claim 1, wherein the amount of the alkaline aqueous solution used in the step (A) and the amount of water used in the step (B) is 10 mL or more with respect to the capacity of 1 Wh of the lithium ion secondary battery.
The method according to claim 1 or 2, wherein the step (A) is performed in an inert gas atmosphere or a reducing gas atmosphere.
The method according to any one of claims 1 to 3, wherein the pH of the alkaline aqueous solution in the step (A) is 10 to 14, and the pH of the water in the step (B) is 6 to 14.
The claim that the alkaline compound used as the alkaline aqueous solution is at least one selected from the group consisting of calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, sodium hydroxide, potassium hydroxide and lithium hydroxide. The method according to any one of 1 to 4.
The method according to any one of claims 1 to 5, wherein in the step (A), the alkaline aqueous solution is lime water.
The method according to any one of claims 1 to 6, wherein the content of the alkaline compound in the alkaline aqueous solution is larger than the saturation concentration.
The step of opening the lithium ion secondary battery is to crush or cut the lithium ion secondary battery, to make a hole penetrating the casing of the lithium ion secondary battery, or to make a casing of the lithium ion secondary battery. The method according to any one of claims 1 to 7, which is a step of opening a part or all of the above.
The method according to any one of claims 1 to 8, wherein the steps (A) and (B) are carried out at 10 to 80 ° C.
The method according to any one of claims 1 to 9, wherein the timing of completion of deactivation is determined from the state of generation of air bubbles from the opening.
It is a method of visualizing the deactivation status of lithium-ion secondary batteries.
(A) A step of opening the lithium ion secondary battery in an alkaline aqueous solution, or (B) a step of opening the lithium ion secondary battery in water under an inert gas atmosphere or a reducing gas atmosphere. A method of visualizing the deactivation status of a lithium-ion secondary battery by generating air bubbles from the opening.
It is a method of separating and recovering metal elements from a lithium ion secondary battery.
A step of deactivating a lithium ion secondary battery by the method according to any one of claims 1 to 11 and then crushing the deactivated lithium ion secondary battery and physically sorting the deactivated lithium ion secondary battery. Method.
The method according to claim 12, wherein at least one selected from the group consisting of lithium, nickel and cobalt is recovered as a solid oxide, and copper and / or aluminum is recovered as a metal.
(A1) A step of sorting a casing with a control substrate by size from the inactivated solid matter of a lithium ion secondary battery and recovering aluminum.
(A2) Claim 12 or claim 12, further comprising a step of recovering at least one selected from the group consisting of copper scraps, aluminum scraps and separator pieces by sieving (1) from the solid matter remaining in the step (A1). 13. The method according to 13.
After the step (A2)
(A3) A step of recovering a separator piece by sieving (2) from the solid matter remaining in the step (A2), and (A4) Copper scrap and aluminum scrap from the solid matter remaining in the step (A3). 14. The method of claim 14, further comprising a step of separating.
After the step (A2)
(B3) The suspension of the deactivated lithium ion secondary battery is filtered, and at least selected from the group consisting of oxides of lithium, cobalt, nickel and manganese, graphite powder, aluminum hydroxide and calcium fluoride. The method according to claim 14, further comprising a step of separating one type.
A lithium ion secondary battery deactivating device used to deactivate a lithium ion secondary battery in an alkaline aqueous solution or water.
A chamber in which an alkaline aqueous solution or water is stored, and
A lithium ion secondary battery deactivating device that is arranged in the chamber and includes a mechanism for opening the lithium ion secondary battery charged in the chamber.
An openable and closable lid that is placed on the chamber and is formed on the alkaline aqueous solution or water to isolate the closed space from the outside.
The lithium ion secondary battery deactivating apparatus according to claim 17, further comprising a gas supply unit that supplies an inert gas or a reducing gas to the closed space.
A vehicle comprising the lithium ion secondary battery deactivating device according to claim 17 or 18.
A lithium ion secondary battery recycling method using the method according to any one of claims 1 to 11.