JP2023124857A - Method for deactivating lithium-ion secondary battery - Google Patents

Abstract

To provide a simple and safe method for deactivating a lithium-ion secondary battery while suppressing the generation of oxygen gas.SOLUTION: The method is for deactivating a lithium-ion secondary battery. The method includes a step (1) for immersing the lithium-ion secondary battery in an aqueous solution including halide ions and/or a reducing agent. The reducing agent is a reductant (Red) having a standard redox potential redox pair (Ox/Red) that is baser than the standard redox potential of O2/H2O in a pH of the aqueous solution.SELECTED DRAWING: None

Description

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

As the demand for lithium ion secondary batteries increases in modern society, the importance of efficient recycling of used lithium ion secondary batteries (waste lithium ion secondary batteries) also increases. In particular, since lithium ion secondary batteries contain rare resources, it is preferable to recycle the waste batteries. However, lithium ion secondary batteries contain a highly reactive lithium (Li) compound, and there have been reports of accidents in which they ignite due to improper handling. Explosions have also occurred in the past when processing waste lithium-ion secondary batteries. For these reasons, "safe deactivation and dismantling" has become an issue especially for large lithium-ion secondary batteries used in electric vehicles and the like. High-temperature incineration or high-temperature steam treatment of waste lithium-ion secondary batteries is also envisioned, but detoxification of harmful gases produced by combustion, decomposition, evaporation, etc. of organic solvents in lithium-ion secondary batteries. For these reasons, a large processing facility is required. In addition, it is difficult to disperse and install such large-scale facilities in various places, so when transporting large waste lithium-ion secondary batteries to the treatment plant, special containers are used to ensure safety. must be carefully packed and transported.

Under such circumstances, as a method for deactivating waste lithium ion secondary batteries for recycling, for example, Patent Document 1 describes incinerating waste lithium ion secondary batteries after discharging. there is Further, Patent Document 2 describes mechanical dry pulverization of a lithium ion secondary battery in an atmosphere of argon, carbon dioxide, or the like.

As in Patent Document 1, many studies have been conducted on the premise of deactivating lithium by high-temperature incineration, but in this case, high-temperature incineration equipment is required, avoiding the need for large-scale processing equipment. In addition to being unsuitable for distributed treatment in urban areas, there is the problem of detoxifying the harmful fluorine-containing gas generated by the combustion of the organic solvent contained in the electrolyte of the lithium-ion secondary battery. Moreover, in the method of Patent Document 1, lithium and aluminum cannot be recovered because they are distributed in the slag phase. On the other hand, in the method of Patent Document 2, even in an atmosphere of argon, carbon dioxide, etc., the dry pulverization is a very dangerous method in which waste lithium ion secondary batteries can violently ignite and generate heat. is unsuitable for safe deactivation of lithium-ion secondary batteries. Therefore, in order to prevent the generation of heat and harmful gases, in Patent Document 3, the lithium ion secondary battery is cut or crushed in a liquid of water, alcohol, acid or in an inert gas, and in Patent Document 4, it is shredded in water. A method has been developed to do However, if the lithium-ion secondary battery is disconnected in water and acid without controlling the atmosphere, gas is generated due to hydrolysis of organic solvents such as carbonate contained in the electrolyte, and storage of the solution after deactivation Dangerous to transport.

Therefore, as a method for deactivating a lithium ion secondary battery that can solve such problems, in Patent Document 5, lithium ions in water under an inert gas atmosphere or a reducing gas atmosphere, or in an alkaline aqueous solution It is known to open the secondary battery, which suppresses fire, dilutes the reaction gas generated when the lithium ion secondary battery is opened, and enables safe deactivation of the lithium ion secondary battery. Ta.

U.S. Patent Application Publication No. 2005/0235775 Japanese Patent Publication No. 2007-531977 JP-A-6-141805 WO2017/006209 WO2021/201151

In Patent Document 5, hydrogen gas is mainly assumed as the reaction gas, and the danger of flames due to hydrogen gas can be eliminated. However, as the experimental verification progressed, it became clear that a considerable amount of oxygen gas was generated depending on the dismantling conditions. This is because oxygen gas is generated from the aqueous solution due to the oxidation action of the positive electrode of the lithium ion secondary battery. When oxygen gas is generated in this manner, an opportunity for contact-mixing of hydrogen gas and oxygen gas in the apparatus eventually occurs. Therefore, there is a demand for a method for deactivating a lithium ion secondary battery while suppressing the generation of oxygen gas. Such a case is considered to be remarkable when the positive electrode is peeled off from the aluminum foil, or after the aluminum foil is completely oxidized. There is concern about ignition and explosion of hydrogen gas.

An object of the present invention is to solve the above problems, and to provide a method for easily and safely deactivating a lithium ion secondary battery while suppressing the generation of oxygen gas.

The present inventors have made intensive studies to solve the above problems, and found that oxygen gas is generated by immersing a lithium ion secondary battery in an aqueous solution containing halide ions and/or a specific reducing agent. It was found that the deactivation treatment of the lithium ion secondary battery can be performed simply and safely while suppressing the Based on these findings, the present inventors have further studied and completed the present invention. That is, the present invention includes the following aspects.

Section 1. A method for deactivating a lithium ion secondary battery, comprising:
(1) comprising a step of immersing the lithium ion secondary battery in an aqueous solution containing halide ions and/or a reducing agent;
The reducing agent is a reductant (Red) having a redox pair (Ox/Red) with a standard redox potential lower than the standard redox potential of O ₂ /H ₂ O at the pH of the aqueous solution. .

Section 2. Item 1. The method according to Item 1, wherein the aqueous solution is an alkaline aqueous solution.

Item 3. Item 3. The method according to Item 1 or 2, wherein the halide ion is at least one selected from the group consisting of chloride ion, bromide ion and iodide ion.

Section 4. 4. The method according to any one of items 1 to 3, wherein the halide ion concentration is 1.00×10 ⁻⁵ to 3.0 mol/L.

Item 5. Item 5. The method according to any one of Items 1 to 4, wherein the reducing agent is at least one selected from the group consisting of iodide ions, sulfur-based oxoacids, phosphorus-based oxoacids, and organic acids.

Item 6. Item 6. The method according to any one of Items 1 to 5, wherein the reducing agent has a concentration of 1.00×10 ⁻⁵ to 3.0 mol/L.

Item 7. Item 7. The method according to any one of Items 1 to 6, wherein the step (1) is performed under an inert gas atmosphere or a reducing gas atmosphere.

Item 8. Item 8. The method according to any one of Items 1 to 7, wherein in the step (1), the aqueous solution is a solution of an alkaline earth metal compound.

Item 9. Item 9. The method according to Item 8, wherein the alkaline earth metal compound has a concentration of 1.00×10 ⁻⁵ to 3.0 mol/L.

Item 10. Item 10. The method according to any one of Items 1 to 9, wherein in the step (1), the aqueous solution is lime water.

Item 11. After the step (1),
(2) The method according to any one of items 1 to 10, comprising the step of opening the lithium ion secondary battery in the aqueous solution.

Item 12. Item 12. The method according to Item 11, wherein the step (2) is performed under an inert gas atmosphere or a reducing gas atmosphere.

Item 13. The step of opening the lithium ion secondary battery includes crushing or cutting the lithium ion secondary battery, making a hole penetrating the casing of the lithium ion secondary battery, or the casing of the lithium ion secondary battery. 13. The method according to Item 11 or 12, which is a step of partially or entirely unsealing.

Item 14. 14. The method according to any one of Items 11 to 13, wherein in the step (2), the lithium ion secondary battery is immersed in an aqueous solution for 10 minutes or more after opening the lithium ion secondary battery.

Item 15. After the step (2),
(3) The method according to any one of items 11 to 14, comprising a step of drying the deactivated lithium ion secondary battery.

Item 16. A method for separating and recovering metal elements from a lithium ion secondary battery,
After deactivating the lithium ion secondary battery by the method according to any one of items 11 to 15, the deactivated lithium ion secondary battery is pulverized and physically sorted. A method. .

Item 17. A lithium ion secondary battery deactivation device used for deactivating a lithium ion secondary battery,
a chamber in which an aqueous solution containing halide ions and/or a reducing agent is stored;
A mechanism for opening a lithium ion secondary battery placed in the chamber and placed in the chamber,
The reducing agent is a reductant (Red) having a redox pair (Ox/Red) with a standard redox potential lower than the standard redox potential of O ₂ /H ₂ O at the pH of the aqueous solution. Ion secondary battery deactivation device.

Item 18. an openable/closable lid placed on the chamber for isolating a closed space formed above the aqueous solution from the outside;
Item 18. The lithium ion secondary battery deactivation device according to Item 17, further comprising a gas supply unit that supplies inert gas or reducing gas to the closed space.

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

Item 20. Item 19. A portable plant comprising the lithium ion secondary battery deactivation device according to Item 17 or 18.

Item 21. Item 17. A lithium ion secondary battery recycling method using the method according to any one of Items 1 to 16.

ADVANTAGE OF THE INVENTION According to this invention, a waste lithium ion secondary battery can be deactivated simply and safely, suppressing generation of oxygen gas. Therefore, the deactivated product can be easily and safely transported, and the recycling of waste lithium ion secondary batteries can be promoted.

The structure 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 metal elements from a lithium ion secondary battery will be shown. An example of a vehicle in which waste lithium-ion secondary batteries can be deactivated on-site (automobile dismantling factories, accident sites, etc.) and elements can be separated and recovered is shown. 1 shows a schematic diagram of a lithium-ion secondary battery deactivation device of the present invention; FIG. (a) Appearance photograph. (b) Plan view. (c) Cross-sectional view. It is a photograph explaining the meaning of "without pretreatment", "opening" and "cutting" in the present example. In Reference Example 1, the results of analyzing the oxygen concentration and hydrogen concentration during deactivation using gas chromatography (GC) are shown. 1 shows a flow chart of deactivation treatment and element separation treatment of a lithium ion secondary battery in Reference Example 1. FIG. The appearance of the separated sample is also shown. 1 shows a flow chart of deactivation treatment and element separation treatment of a lithium ion secondary battery in Reference Example 1. FIG. Also shown are the recoveries of the separated samples. The outline of the apparatus used in Examples 1 and 2 is shown. 2 shows the results of gas chromatography in Example 1. FIG. Hypothetical polarization curves for each reaction in LiCl-added lime water are shown. Hypothetical polarization curves for each reaction in LiF-added lime water are shown. The outline of the apparatus used in Examples 3 to 6 and Comparative Example 1 is shown. 1 shows the measurement results of the immersion potential of Comparative Example 1 using the LiOH-added lime water of Synthesis Example 5. 3 shows the measurement results of the immersion potential of Comparative Example 2 using the CH ₃ COOLi-added lime water of Synthesis Example 6. FIG. Examples 3 to 6 using LiCl-added lime water A of Synthesis Example 1, LiF-added lime water A of Synthesis Example 2, LiCl-added lime water B of Synthesis Example 3, or LiF-added lime water B of Synthesis Example 4 4 shows the measurement results of immersion potential. Figure 2 shows a potential-pH diagram for the _IH2O system. FIG. 10 shows the measurement results of the immersion potential of Example 7 using the LiI-added lime water of Synthesis Example 6. FIG. FIG. 10 shows measurement results of the immersion potential of Example 8 using thiourea of Synthesis Example 8 and CH ₃ COOLi-added lime water. FIG. FIG. 10 shows the measurement results of the immersion potential of Example 9 using the ascorbic acid of Synthesis Example 9 and CH ₃ COOLi-added lime water. FIG. FIG. 10 shows the measurement results of the immersion potential of Example 10 using ascorbic acid, CH ₃ COOLi and LiOH-added lime water of Synthesis Example 10. FIG.

In this specification, when a numerical range is expressed as "A to B", it means from A to B. "Contain" also includes "comprise," "consist essentially of," and "consist of."

1. Method for Deactivating Lithium Ion Secondary Battery First, FIG. 1 shows the structure of a general small lithium ion secondary battery and the raw material prices 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 attached with a control board appears. These materials include 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. Of these, when the raw material prices of each member are compared, the positive electrode active material accounts for about 79% of the total, and all of them contain lithium. In other words, considering the recycling efficiency from the lithium-ion secondary battery, it is preferable to recover lithium, and more preferably to recover the metal elements in the positive electrode active material, particularly nickel and cobalt.

On the other hand, in the method of deactivating a conventional lithium ion secondary battery, many studies have been conducted on the premise of deactivating a lithium compound by high-temperature incineration, as in Patent Document 1. In this case, high-temperature incineration facilities and large-scale processing facilities are required to detoxify the gas containing harmful fluorine generated by the combustion of the organic solvent contained in the electrolyte. Not suitable for processing.

In the method of deactivating a lithium compound by high-temperature incineration, as in Patent Document 1, a lithium-ion secondary battery is heated and melted in a high-temperature furnace to dissolve valuables into the molten alloy. After this, the alloy is acid leached and the elements are separated by solvent extraction. However, in the method of Patent Document 1, lithium and graphite cannot be recovered because they are distributed in the slag phase. For this reason, the lithium contained in the lithium ion secondary battery cannot be recovered. In other words, the conventional method of deactivating a lithium ion secondary battery cannot be said to be an efficient recycling method.

In contrast, the method for deactivating the lithium ion secondary battery of the present invention includes:
(1) comprising a step of immersing the lithium ion secondary battery in an aqueous solution containing halide ions and/or a reducing agent;
The reducing agent is a reductant (Red) having a redox pair (Ox/Red) with a standard redox potential lower than the standard redox potential of O ₂ /H ₂ O at the pH of the aqueous solution.

Also, after step (1),
(2) It is preferable to include the step of opening the lithium ion secondary battery in the aqueous solution. As a result, oxygen gas is less likely to be generated in the aqueous solution, and the deactivation treatment can be performed more safely.

After the deactivation treatment is completed, it can be left as it is, but after the step (2),
(3) It is also preferable to complete the reaction in the deactivation treatment by drying the deactivated lithium ion secondary battery.

When a lithium-ion secondary battery is treated in an aqueous solution, aluminum foil is used as the positive electrode current collector and Li _0.23 Ni _0.86 Co _0.14 O ₂ is used as the positive electrode active material (a small amount is used in the NCA positive electrode). material excluding Al, which is a contained component, the same applies hereinafter), assuming that the change in the amount of lithium in the positive electrode is ΔX _Li ,
Oxidation reaction:
(1) 4OH ⁻ → O ₂ + 2H ₂ O + 4e
(2) Al + 3OH ⁻ → Al(OH) ₃ + 3e
Reduction reaction:
(3) Li _0.23 Ni _0.86 Co _0.14 O ₂ + ΔX _Li Li ⁺⁺ ΔX _Li e
→ Li _{0.23 + ΔX Li} Ni _0.86 Co _0.14 O ₂
(4) 2H ₂ O + 2e → H ₂ + 2OH ^-
is assumed.

When halide ions (especially chloride ions, bromide ions, iodide ions, etc.) are included in the aqueous solution, aluminum oxidation and hydrogen generation, that is, reactions (2) and (4) mainly proceed. It is assumed that no oxygen gas is generated.

Thus, in the method of deactivating the lithium ion secondary battery of the present invention, lithium By opening the ion secondary battery, it is possible to moderately deactivate the lithium compound contained in the lithium ion secondary battery while suppressing the generation of oxygen gas. Moreover, the method for deactivating the lithium ion secondary battery of the present invention is useful in that lithium, nickel and cobalt can be recovered as solids, and copper and aluminum can be recovered as metals. is.

The method for deactivating a lithium ion secondary battery of the present invention does not generate toxic gas, can be carried out with relatively small equipment, and can safely dismantle the lithium ion secondary battery. be.

Therefore, lithium ion secondary batteries can be easily and safely dismantled even in urban areas such as garbage incinerators and automobile dismantling sites, and lithium ion secondary batteries can be easily and safely dismantled and transported. Is possible.

(1-1) Aqueous Solution In step (1), the lithium ion secondary battery is immersed in an aqueous solution containing halide ions and/or a reducing agent.

The aqueous solution that can be used in step (1) is not particularly limited, and any of an acidic aqueous solution, a neutral aqueous solution and an alkaline aqueous solution can be employed. For example, it is expected that an acidic aqueous solution can strengthen the oxidizing action of aluminum, suppress the oxygen evolution reaction, and safely perform the deactivation treatment. Further, according to FIG. 17 (potential-pH diagram of IH ₂ O system) described later, IO ₃ ⁻ /I ⁻ , IO ₃ ⁻ /I ₃ ⁻ , IO ₃ Since the redox potential such as ⁻ /I ₂ is a more noble (lower) potential than the redox potential of O ₂ /H ₂ O, the oxidation reaction of iodide ion (I ⁻ ) is more likely than the oxygen generation reaction. is given priority, and it can be understood that the generation of oxygen gas can be suppressed. However, the generated carbon dioxide is easily captured by reacting it with an alkaline aqueous solution (when lime water is used as the alkaline aqueous solution, it is easily fixed as calcium carbonate), so it promotes the decomposition reaction of carbonate below, and organic An alkaline aqueous solution is preferred, which may have a similar effect from the standpoint of fixing carbon dioxide, which is a reaction product of the acid. In addition, as the lithium ion secondary battery is crushed in the aqueous solution, it is assumed that the battery components are eluted and the composition is changed (polluted). The aqueous solution used in the present invention also includes an aqueous solution whose composition has changed (contaminated) due to the elution of battery components after the crushing treatment of the lithium ion secondary battery. That is, after the lithium ion secondary battery is deactivated by the method of the present invention, the used aqueous solution is used to continuously deactivate the lithium ion secondary battery by the method of the present invention. It is also possible to carry out an activation treatment.

When an alkaline aqueous solution is used as the aqueous solution in step (1), the alkaline compound contained in the alkaline aqueous solution is not particularly limited as long as it exhibits alkalinity (especially about pH 10 to 14) when dissolved in water. , calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. These alkali compounds can be used alone or in combination of two or more.

If the content of the alkaline compound in the alkaline aqueous solution is below the saturation concentration, the alkaline compound will be 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 to cause the following reaction.

At this time, the carbon dioxide dissolved in the water reacts with the alkali compound and precipitates, thus promoting the hydrolysis of the carbonate of the above formula. For example, if the alkaline compound is calcium hydroxide, it reacts with carbon dioxide to form calcium carbonate as follows.

In addition to the carbonate decomposition reaction described above, the alkali compound is also consumed in the decomposition reaction of LiPF ₆ described below. Therefore, if the content of the alkaline compound in the alkaline aqueous solution is less than the saturation concentration, the alkaline compound will be consumed by the reaction during the deactivation treatment of the lithium ion secondary battery, and the decomposition reaction of carbonate and LiPF ₆ will proceed. It may become difficult and may not be able to be completely detoxified.

Therefore, when using an alkaline aqueous solution in the step (1), it is preferable that the content of the alkaline compound in the alkaline aqueous solution is set to a saturated concentration or higher so that a part of the alkaline compound is precipitated. As a result, even if the alkaline compound is consumed by the reaction during the deactivation treatment of the lithium ion secondary battery, the concentration of the alkaline compound can be replenished by dissolving in the alkaline aqueous solution from the precipitate.

For example, when calcium hydroxide is used as the alkaline compound, only 0.17 g of calcium hydroxide dissolves in 100 mL of water at room temperature. It is preferable to add, for example, 0.17 to 100 g, particularly 0.4 to 10 g, to 100 mL of water.

In addition, the decomposition of _LiPF6 yields alkaline earth metal compounds with low solubility such as magnesium fluoride and calcium fluoride compared to alkali metal compounds with high solubility such as sodium fluoride and potassium fluoride. (In particular, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide; alkaline earth metal oxides such as magnesium oxide and calcium hydroxide) are more effective, so the decomposition rate is faster. is assumed and preferable.

The pH of the aqueous solution used in step (1) is not particularly limited and can be from 1 to 14. From the viewpoint of, 3 to 14 are preferable, and 4 to 13 are more preferable. When the aqueous solution used in step (1) is an alkaline aqueous solution, its pH can be adjusted to 10-14, preferably 11-13.

In the present invention, halide ions contained in the aqueous solution are not particularly limited, and fluoride ions, chloride ions, bromide ions, iodide ions, and the like can be employed. However, when lime water (aqueous calcium hydroxide solution) is used as the aqueous solution, that is, when calcium hydroxide or calcium oxide is included as the alkaline compound, the concentration of fluoride ions should be increased to react with calcium ions. is difficult. The higher the halide ion concentration, the easier it is to reduce the amount of oxygen gas generated. Chloride ions are preferred, and chloride ions are more preferred.

The above halide ion is not particularly limited, but is preferably introduced as a lithium salt, considering that the present invention is a method for deactivating a lithium ion secondary battery. That is, the aqueous solution containing halide ions is obtained by adding lithium halides such as lithium fluoride, lithium chloride, lithium bromide, and lithium iodide, as well as halogen-containing lithium salts such as LiPF ₆ and LiBF ₄ . More preferably, lithium chloride, lithium bromide, lithium iodide, etc. are added, lithium chloride, lithium iodide, etc. are further preferably added, and lithium chloride is particularly preferably added.

In the present invention, the concentration of halide ions contained in the aqueous solution is not particularly limited. ×10 ^-5 to 3.00 mol/L is preferable, 1.00×10 ^-3 to 1.00 mol/L is more preferable, 5.00×10 ^-2 to 0.80 mol/L is more preferable, and 0.15 ~0.70 mol/L is particularly preferred.

In the present invention, _the reducing agent contained in _the aqueous solution is not particularly limited. It is preferable to employ a reductant (Red) having (Ox/Red), iodide ion, low-valent sulfur-based oxoacid ion (e.g., hydrogen sulfite ion, thiosulfate ion, disulfite ion, dithionite monovalent to pentavalent sulfur-based oxoacid ions, etc.), urea compounds (e.g., urea, thiourea, thiourea dioxide, etc.), low-valent phosphorus-based oxoacid ions (e.g., phosphite ion, monovalent to trivalent phosphorus-based oxoacid ions such as phosphite ions), organic acids (e.g., monocarboxylic acids such as formic acid; polycarboxylic acids such as oxalic acid, citric acid and aspartic acid; lactones such as ascorbic acid) etc. can be adopted. When these reducing agents are used, the oxidation of the reducing agent takes precedence over the generation of oxygen, and the generation of oxygen gas can be suppressed. Preferred are iodide ions, urea compounds, organic acids, and the like, from the viewpoints of less generation of oxygen gas in an aqueous solution and easier deactivation treatment.

The above-described reducing agent is not particularly limited, but can be added as it is, or in the form of a lithium salt, considering that the present invention is a method for deactivating a lithium ion secondary battery. can also That is, the aqueous solution containing the reducing agent contains lithium iodide; urea compounds such as urea, thiourea, and thiourea dioxide; sulfur-based lithium oxo acids such as lithium hydrogen sulfite, lithium thiosulfate, and lithium disulfite; Phosphorus-based lithium oxoacids such as lithium phosphate and lithium hypophosphite; organic acids such as formic acid, oxalic acid, citric acid, aspartic acid and ascorbic acid; lithium formate, lithium oxalate, lithium citrate, lithium aspartate, It is preferable to add lithium organic acid such as lithium ascorbate, and it is more preferable to add lithium iodide.

In the present invention, the concentration of the reducing agent contained in the aqueous solution is not particularly limited. 10 ⁻⁵ to 3.00 mol/L is preferable, 1.00×10 ⁻³ to 1.00 mol/L is more preferable, 5.00×10 ⁻² to 0.80 mol/L is more preferable, and 0.15 to 0.70 mol/L is particularly preferred.

The amount of the aqueous solution used in step (1) is preferably excessive. Specifically, it will be described in detail below.

In the present invention, the active lithium compound in the lithium ion secondary battery comes into contact with water, reacts preferentially, and is gradually deactivated 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 combustible organic solvent contained in the electrolyte 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, the reaction does not generate oxygen. Since the aqueous solution also functions as a cooling agent to prevent rapid temperature rise, ignition and heat generation can be suppressed, which is a safe method. Also, an excess amount of water does not cause a shortage of water (H ₂ O) in the above reaction.

In this reaction, hydroxide ions are generated, but they are consumed in the later-described decomposition reaction of carbonate and _LiPF6 , so the pH should be maintained within an appropriate range of acidic, neutral, or alkaline. , it is easy to continue the deactivation treatment.

Based on the above, the amount of the aqueous solution used in step (1) is preferably excessive, and is preferably 50 mL or more, more preferably 100 mL or more, more preferably 500 mL or more, relative to the capacity of the target lithium ion secondary battery 1 Wh. is more preferred. The amount of the aqueous solution used in the step (1) should be as large as possible, and the upper limit is not particularly limited. For this reason, the aqueous solution is preferably 20 L or less with respect to the capacity of 1 Wh of the target lithium-ion secondary battery. Generally, it is particularly preferable to use about 75 mL to 15 L with respect to 1 Wh of capacity of the target lithium ion secondary battery.

In addition, in the method for deactivating the lithium ion secondary battery of the present invention, the lithium ion secondary battery to be charged is not particularly limited. For example, a used waste lithium ion secondary battery can be put in as it is, or a used waste lithium ion secondary battery can be put in after performing a discharge treatment in advance. In this way, when the discharge treatment is performed in advance, when the method of deactivating the lithium ion secondary battery of the present invention is adopted, there is a concern that hydrogen gas and oxygen gas will be generated and hydrogen explosion will occur. Furthermore, it is easy to reduce, and it is easy to further reduce the concern that the solvent will burn and explode due to sudden heat generation.

When the used waste lithium ion secondary battery is previously subjected to discharge treatment, the waste lithium ion secondary battery can be immersed in an aqueous solution.

Although the aqueous solution used for the discharge treatment is not particularly limited, an aqueous sodium chloride solution, an aqueous potassium chloride solution, or the like can be used.

However, when the waste lithium ion secondary battery is immersed in an aqueous solution, hydrogen gas is generated from the negative electrode, and the solution changes from neutral to alkaline. Gas is generated. In this case, if oxygen gas is generated from the positive electrode at the same time, there is a concern not only about hydrogen explosion, but also about a decrease in the recovery value of aluminum. In order to suppress such concerns, it is preferable to include a buffer in the aqueous solution in which the waste lithium ion secondary battery is immersed for discharge treatment.

Specifically, boric acid-potassium chloride, sodium hydrogen carbonate, disodium hydrogen phosphate and the like can be employed as such a buffering agent.

The content of the buffering agent in the aqueous solution is not particularly limited, as long as it is contained to the extent that it can maintain weak alkalinity (pH 9 to 11) when the waste lithium ion secondary battery is immersed in the aqueous solution. good. For example, the buffer content can be 0.01-0.5 mol/L.

As described above, in the method for deactivating the lithium ion secondary battery of the present invention, the lithium ion secondary battery is opened in an aqueous solution (step (2)), so that the lithium ion secondary battery It is possible to deactivate the included lithium gently.

In particular, in the method of deactivating the lithium ion secondary battery of the present invention, the carbonate or the like contained as an organic solvent in the electrolytic solution present in the lithium ion secondary battery is hydrolyzed in the aqueous solution and gradually Generates carbon dioxide. At this time, the expected decomposition reaction is assumed to be the following reaction formula, for example, when the carbonate is ethylene carbonate.

The method for deactivating a lithium ion secondary battery of the present invention is useful in that the hydrolysis of an organic solvent such as carbonate is rapid and the time for gas generation can be shortened.

In the aqueous solution, LiPF ₆ contained as an electrolyte salt of the electrolyte present in the lithium ion secondary battery is eluted into the treatment liquid during deactivation treatment of the lithium ion secondary battery. At this time, LiPF ₆ hydrolyzes while producing HF, although equilibrium theory and kinetic studies remain.

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

In addition, in the method of deactivating a lithium ion secondary battery in an aqueous solution coexisting with a reducing agent of the present invention, it is presumed that the corrosion rate of iron-based materials in water is slow, and the lithium ion secondary battery It is possible to use inexpensive iron-based materials for members that come into contact with the treatment liquid in deactivation treatment facilities, etc., and the range of material selection is widened.

(1-2) Atmosphere In the method of deactivating the lithium ion secondary battery of the present invention (steps (1) and (2)), the atmosphere is not particularly limited. Among them, from the viewpoint of making it difficult to generate oxygen gas in an aqueous solution and facilitating safer deactivation, reducing properties such as under an inert atmosphere such as a nitrogen gas atmosphere, an argon gas atmosphere, or a hydrogen gas atmosphere A gas atmosphere is preferred.

When such an atmosphere is adopted, since there is no oxygen in the atmosphere, even if hydrogen gas is generated during the deactivation process of the lithium ion secondary battery, it becomes chemically stable, and the lithium ion It is easier to further suppress the danger of ignition and heat generation of the secondary battery.

(1-3) Temperature The temperature at which the method for deactivating a lithium ion secondary battery of the present invention (steps (1) and (2)) is not particularly limited, and can be carried out at room temperature, for example. That is, high-temperature incineration is unnecessary, and a simpler and safer method can be achieved. Specifically, the temperature at which the lithium ion secondary battery deactivation method (steps (1) and (2)) of the present invention is performed is, for example, 5 to 80°C, preferably 10 to 45°C. can.

In addition, in the method for deactivating a lithium ion secondary battery of the present invention, when the drying step (step (3)) is performed, the drying conditions are not particularly limited, and a conventional method can be followed. Specifically, the temperature at which the drying step (step (3)) is performed is preferably 20 to 300° C., more preferably 30 to 200° C., from the viewpoint of easily completing the deactivation reaction of the lithium ion secondary battery in the present invention. is more preferred.

(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 methods can be employed. Specifically, crushing or cutting the lithium-ion secondary battery, making a hole through the casing of the lithium-ion secondary battery, or opening part or all of the casing of the lithium-ion secondary battery. is mentioned. Note that "crushing the lithium ion secondary battery" means breaking and crushing the lithium ion battery. Furthermore, "crushing or cutting the lithium ion secondary battery" does not mean only crushing or cutting the casing of the lithium ion secondary battery to expose the inside. "Crushing or cutting a lithium-ion secondary battery" refers to crushing or cutting an unspecified position of a lithium-ion secondary battery, and also crushes storage parts such as current collectors and separators placed in the casing. Or it also means to cut.

In addition, in the present invention, the number of times of crushing or cutting the lithium ion secondary battery is not particularly limited as long as it is one or more times, but it is preferable to crush or cut the lithium ion secondary battery a plurality of times. Furthermore, when the lithium ion secondary battery is crushed or cut a plurality of times, it is preferable to crush or cut at different positions. As a result, rapid deactivation can be achieved, and steps such as physical selection in the steps after deactivation can be rapidly advanced.

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. A deactivation treatment of the battery can be performed.

In addition, 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 particularly shortened. In addition, according to the conventional dry method of deactivation in air, if a method of crushing or cutting the lithium ion secondary battery or drilling a hole penetrating the casing of the lithium ion secondary battery is adopted, The lithium ion secondary battery ignites or generates heat, but if the lithium ion secondary battery deactivation method of the present invention is adopted, the lithium ion secondary battery can be crushed or cut, or the lithium ion secondary battery can be destroyed. The lithium ion secondary battery can be deactivated safely even if a hole is made through the casing of the battery.

(1-5) Immersion treatment After subjecting the lithium ion secondary battery to the opening treatment as described above, the active lithium compound in the lithium ion secondary battery comes into contact with the aqueous solution and reacts preferentially. , gradually deactivating 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 combustible organic solvent contained in the electrolyte of the lithium ion secondary battery is dissolved in the aqueous solution and diluted, and the oxygen concentration is constant before and after the reaction, that is, the reaction does not generate oxygen. However, since the aqueous solution also functions as a cooling agent to prevent a rapid temperature rise, ignition and heat generation can be suppressed, which is a safe method.

By measuring the immersion potential while the lithium ion secondary battery is immersed in the aqueous solution, it is possible to determine whether the reaction of the positive electrode in the deactivation treatment is completed. The time point when there is no more room for oxygen _to be generated in the aqueous solution is defined as the _end of the deactivation treatment of the positive electrode. Since there is no more room for oxygen gas to be generated, it can be determined that the positive electrode deactivation process is completed. A specific immersion time can be, for example, 10 minutes to 130 minutes, taking into consideration not only the suppression of oxygen gas generation from the positive electrode, but also the suppression of hydrogen gas generation from the negative electrode. For example, when chloride ions, bromide ions, or the like are included as halide ions, the immersion potential is lower than the O ₂ /H ₂ O redox potential in about 1 minute after the lithium ion secondary battery is immersed. Therefore, even if the immersion time is about 1 minute, the deactivation treatment of the positive electrode can be completed. In consideration of the deactivation treatment of the negative electrode, the immersion time is preferably 10 minutes or more. . In addition, when a reducing agent is included, the immersion potential becomes lower than the O ₂ /H ₂ O redox potential in about 15 seconds to 7 minutes after the lithium ion secondary battery is immersed. It can be determined that the deactivation process is finished. The immersion time can be, for example, 10 minutes to 130 minutes in consideration of the deactivation treatment of the negative electrode as described above. However, in any case, when only the positive electrode of the lithium ion secondary battery is deactivated, a short immersion of about 1 to 7 minutes is sufficient. On the other hand, when fluoride ions are included as halide ions, the immersion potential becomes lower than the O ₂ /H ₂ O redox potential in about 11 to 22 minutes after the lithium ion secondary battery is immersed. So, the immersion time can be, for example, 11 minutes to 42 minutes, and depending on the fluoride ion concentration, it can be 11 to 13 minutes, or it can be 22 to 42 minutes.

2. Method for Separating and Recovering Metal Elements from Lithium-Ion Secondary Batteries In the method for deactivating lithium-ion secondary batteries of the present invention, no toxic gas is generated, the equipment can be relatively small, and the method is safe. It is possible to dismantle the lithium ion secondary battery.

Therefore, it is possible to easily and safely deactivate the lithium ion secondary battery even in urban areas such as garbage incinerators and car dismantling sites, as well as at automobile accident sites. It can be easily and safely dismantled and transported, and each element can be separated and recovered from it. An example of this separation and recovery method is shown in FIG.

Lithium ion secondary batteries that have been safely deactivated in this way or their crushed materials contain metal elements such as lithium, aluminum, copper, nickel, cobalt, manganese, etc. It is possible to separate and recover them by appropriate treatment.

In the method for deactivating the lithium ion secondary battery of the present invention, for example, a hole is made through the casing of the lithium ion secondary battery, or 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 subsequent processing. Note that FIG. 2 shows an example in which a lithium ion secondary battery is deactivated by a cutting process using the cutting device shown in FIG.

Specifically, casings with control boards can be first sorted by size from the solids after deactivation. From here it is possible to recover a lot of aluminum. After that, 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 iron balls 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) with an opening of about 0.5 to 3 mm (1 mm in FIG. 2), for example. Iron balls can be recovered from this mixture by magnetic separation, and separator pieces can be recovered by sieving (2) with an opening of about 5 to 15 mm (10 mm in FIG. 2). The remainder is a mixture of scrap copper and scrap aluminum, which can be separated by physical sorting such as eddy current sorting and shipped to existing processing plants.

On the other hand, by filtering the suspension after the sieving (1), oxides such as lithium, cobalt, nickel, manganese, etc., graphite powder, aluminum hydroxide, calcium fluoride, etc. can be separated. can be done. These can be processed at medium-scale smelters specializing in waste lithium-ion secondary battery waste and existing smelters. About 70% of lithium and most of nickel, cobalt, etc. can be recovered from this as a solid.

Most valuable elements can be recovered as solids, and lithium, graphite, etc., which are difficult to recover by conventional dry processing, can be concentrated and separated as solids by the method of the present invention, which is useful. . In addition, since copper and aluminum can be recovered as metals in the method of the present invention, chemical treatments such as acid leaching and reduction, which are required in dry processes, are not required, and can be easily recycled thereafter.

As described above, according to the method for deactivating a lithium ion secondary battery of the present invention, it is possible to realize a wet recycling process that is extremely compact and has a high recovery rate of valuables compared to the dry process. Preferably, transportation of large-sized waste lithium ion secondary batteries to a collection facility or a smelter can be transformed into a safe and convenient one. For example, waste lithium-ion secondary batteries, which have been a bottleneck by installing treatment plants in various places such as garbage incineration plants and car dismantling sites, and deactivating lithium-ion secondary batteries at each treatment plant It is possible to solve the transportation problem of batteries.

In addition, if a vehicle equipped with a lithium ion secondary battery deactivation device such as the example shown in FIG. A waste lithium ion secondary battery such as a broken car is put into the chamber of the container, then the waste lithium ion secondary battery is cut and crushed by a cutting and crushing unit (for example, a pair of rollers facing the cutting blade), and then , a conveyer or the like can transport the cut lithium ion secondary battery, dry it if necessary, and collect the crushed material. At this time, the immersion time can be adjusted by adjusting the moving speed of the conveyor or the like.

Here, the portion into which the waste lithium-ion secondary battery is put is provided with a mechanism for isolating it from the atmosphere. This mechanism seals the space formed above the lid and the aqueous solution to form a closed space isolated from the outside. In this state, when an inert gas (nitrogen gas) is supplied from the gas supply unit (nitrogen generator) through the tube, the closed space is filled with the inert gas to form an inert gas atmosphere. Note that when a reducing gas (for example, hydrogen gas or the like) is supplied, the closed space is filled with the reducing gas, and a reducing gas atmosphere can be formed.

The vehicle is provided with a dehydrating and drying device, and the crushed matter can be separated by passing the crushed matter together with the aqueous solution in the chamber. The aqueous solution from which the crushed matter has been removed is supplied again into the chamber.

In other words, it can be carried out at a car dismantling site or a site where waste lithium ion secondary batteries are generated. After that, it can be transported to a dedicated treatment facility or smelter, where various metal elements can be recycled and waste liquid treatment can be performed. From the above, it can be used as a pretreatment station in various parts of the world, including developing countries.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited only to the examples.

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

In this embodiment, as shown in FIG. 5, "opening" means that only a part of the casing is removed so as not to damage the lithium ion secondary battery existing in the casing, and the battery existing in the casing is removed. It means exposing the lithium-ion secondary battery that

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

Reference Example 1: The deactivation behavior when a lithium ion secondary battery immersed in a deactivation treatment in lime water and an element recovery aqueous solution was cut was investigated at 23 to 25°C. FIG. 2 shows a flow chart of deactivation processing of a lithium ion secondary battery. In a glove box in 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. The chamber 1 of the lithium ion secondary battery cutting apparatus shown in FIG. The installed lithium ion secondary battery was immersed. After that, the apparatus was operated, and the lithium ion secondary battery was pressed against a blade 3 made of stainless steel installed in the chamber 1 with a rotating rod 4 to cut it. At this time, a drop lid 5 was arranged in the chamber 1 for safer operation. When the lithium ion secondary battery could not be disconnected by one operation of the device, the device was operated repeatedly to disconnect the lithium ion secondary battery.

After the cutting, the lithium ion secondary battery was allowed to stand in a state of being immersed in the treatment liquid until generation of air bubbles was completed, and the gas was appropriately sampled. The sampled gas was analyzed for oxygen concentration and hydrogen concentration by gas chromatography (GC-8A, manufactured by Shimadzu Corporation). The results are shown in FIG.

As a result, hydrogen gas was generated during the deactivation treatment, suggesting that lithium in the negative electrode was deactivated by reaction with water. In addition, the oxygen concentration was almost constant, suggesting that the decomposition of the positive electrode active material and the oxidation of water can be ignored.

After completion of the reaction, the treated liquid and the solid matter were taken out from the glove box into the atmosphere, and the solid matter was removed from the casing pieces made of aluminum by manual screening and cut into pieces of about 2 cm×2 cm. It was possible to recover 86.7% of the aluminum as metallic aluminum from the casing thus removed. Next, about 20 iron balls (average diameter of 0.9 cm) and 100 mL of deionized water were placed in a polypropylene bottle, and the solid matter after cutting was ball-milled for 10 hours. After sorting the solids pulverized in this way with a sieve with an opening of 1 mm, the solids on the sieve were separated into iron balls, copper scraps/aluminum scraps, and separator pieces by magnetic separation and sieving with an opening of 10 mm. . A black suspension was recovered under the sieve, and was filtered to recover a black powder and a transparent ball mill liquid. A portion of these collected materials 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. Results are shown in FIGS. As a result, it was possible to recover 69% of lithium metal, 99.2% of nickel, 98.9% of cobalt as solid oxides, and 94.2% of copper as metallic copper.

As described above, it was shown that the lithium ion secondary battery can be safely deactivated by performing the opening treatment of the lithium ion secondary battery in an aqueous solution. It is important to elucidate the reaction behavior of

Synthesis Example 1: LiCl-added lime water A
2.5 g of LiCl was added to 300 mL of lime water in which calcium hydroxide (2 g of calcium hydroxide was added to the treatment solution) was precipitated in a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume). and LiCl-added lime water A was obtained. The ion concentrations calculated from the solubility products shown in Table 1 are Li ⁺ : 0.236 mol/L, Ca ²⁺ : 9.18×10 ⁻³ mol/L, Cl ⁻ : 0.236 mol/L, and pH was 12.26.

Synthesis Example 2: LiF-added lime water A
In a nitrogen atmosphere (oxygen concentration: less than 1% by volume) glove box, 2.5 g of LiF is added to 300 mL of lime water in which calcium hydroxide (2 g of calcium hydroxide is added to the treatment solution) is precipitated. and LiF-added lime water A was obtained. The ion concentrations calculated from the solubility products shown in Table 1 are Li ⁺ : 0.216 mol/L, Ca ²⁺ : 6.36×10 ⁻⁸ mol/L, F ⁻ : 1.16×10 ⁻² mol/ L and the pH was 13.31.

Synthesis Example 3: LiCl-added lime water B
In a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume), LiCl was added to 300 mL of lime water in which calcium hydroxide (4.45 g of calcium hydroxide was added to the treatment solution) was precipitated. 27 g of LiCl-added lime water B was obtained. The ion concentrations calculated from the solubility products shown in Table 1 are Li ⁺ : 0.100 mol/L, Ca ²⁺ : 9.18×10 ⁻³ mol/L, Cl ⁻ : 0.100 mol/L, and pH was 12.26.

Synthesis Example 4: LiF-added lime water B
In a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume), LiF was added to 300 mL of lime water in which calcium hydroxide (4.45 g of calcium hydroxide was added to the treatment solution) was precipitated. 78 g of LiF-added lime water B was obtained. The ion concentrations calculated from the solubility products shown in Table 1 are Li ⁺ : 0.100 mol/L, Ca ²⁺ : 1.27×10 ⁻³ mol/L, F ⁻ : 8.23×10 ⁻⁵ mol/ L and the pH was 12.99.

Synthesis Example 5: LiOH-added lime water 300 mL of lime water in which calcium hydroxide (2.41 g of calcium hydroxide added to the treatment liquid) was precipitated in a glove box with a nitrogen atmosphere (oxygen concentration: less than 1% by volume). 1.70 g of LiOH was added to obtain LiOH-added lime water. The ion concentrations calculated from the solubility products shown in Table 1 were Li ⁺ : 0.24 mol/L, Ca ²⁺ : 2.17×10 ⁻⁴ mol/L, and the pH was 13.4.

Synthesis Example 6: CH ₃ COOLi-added lime water Lime obtained by precipitating calcium hydroxide (2.40 g of calcium hydroxide added to the treatment liquid) in a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume). 7.21 g of CH ₃ COOLi.2H ₂ O was added to 300 mL of water to obtain CH ₃ COOLi-added lime water. The ion concentrations calculated from the solubility products shown in Table 1 were Li ⁺ : 0.236 mol/L, Ca ²⁺ : 1.45×10 ⁻⁵ mol/L, and the pH was 12.5.

Synthesis Example 7: LiI-added lime water 300 mL of lime water in which calcium hydroxide (2.41 g of calcium hydroxide added to the treatment liquid) was precipitated in a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume). 9.47 g of LiI was added to obtain LiI-added lime water. Each ion concentration calculated from the solubility product is Li ⁺ : 0.24 mol/L, Ca ²⁺ : 1.35×10 ⁻² mol/L, I ⁻ : 0.24 mol/L, and the pH is 12.3. Met.

Synthesis Example 8: Thiourea and CH ₃ COOLi-added lime water Precipitate calcium hydroxide (2.40 g of calcium hydroxide added to the treatment liquid) in a glove box under a nitrogen atmosphere (oxygen concentration: less than 1% by volume). 5.39 g of thiourea and 7.21 g of CH ₃ COOLi.2H ₂ O were added to 300 mL of lime water to obtain thiourea- and CH ₃ COOLi-added lime water. The concentrations calculated from the solubility products shown in Table 1 are Li ⁺ : 0.236 mol/L, Ca ²⁺ : 1.45×10 ^-5 mol/L, Thiourea: 0.236 mol/L, and the pH is It was 11.8-12.1.

Synthesis Example 9: Ascorbic acid and CH ₃ COOLi-added lime water Precipitate calcium hydroxide (2.40 g of calcium hydroxide added to the treatment liquid) in a glove box under a nitrogen atmosphere (oxygen concentration: less than 1% by volume). 12.46 g of ascorbic acid and 7.21 g of CH ₃ COOLi.2H ₂ O were added to 300 mL of lime water to obtain ascorbic acid and CH ₃ COOLi-added lime water. Each concentration calculated from the solubility product shown in Table 1 was Li ⁺ : 0.236 mol/L, Ca ²⁺ : 0.11 mol/L, ascorbic acid: 0.236 mol/L, and pH was 5.5. Ta. Since ascorbic acid has dissociation reactions (C ₆ H ₈ O ₆ ⇔ _{C 6} H ₇ O ₆ ^- +H ⁺ , C ₆ H ₇ O ₆ ^- ⇔ C ₆ H ₆ O ₆ ^2- + H ⁺ ), lime water It became weakly acidic upon addition.

Synthesis Example 10: Ascorbic acid, CH ₃ COOLi and LiOH-added lime water Calcium hydroxide in a glove box under a nitrogen atmosphere (oxygen concentration: less than 1% by volume) (2.40 g of calcium hydroxide was put into the treatment liquid) _{To 300} mL _{of lime} water in which Added lime water was obtained. The concentrations calculated from the solubility products shown in Table 1 are Li ⁺ : 0.236 mol/L, Ca ²⁺ : 1.45×10 ⁻⁵ mol/L, ascorbic acid: 0.1 mol/L, and the pH is It was 12.0-12.2. Since the aqueous solution was weakly acidic in Synthesis Example 9, the pH was adjusted to around 12 by adding LiOH.

Examples 1-2 (gas chromatography)
The gas generated from the positive electrode in the aqueous solution was analyzed. In Example 1, the LiCl-added lime water A of Synthesis Example 1 was used, and in Example 2, the LiF-added lime water A of Synthesis Example 2 was used. The properties (oxygen generation, lithium ion intercalation reaction amount, etc.) were evaluated.

In a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume), remove the resin outer casing of the lithium-ion secondary battery, and remove a part of the casing so as not to damage the internal lithium-ion secondary battery. The positive electrode (3×10 cm ² , about 1 to 2 g, aluminum foil coated with positive electrode material Li _0.23 Ni _0.86 Co _0.14 O ₂ on both sides) was taken out.

Next, the positive electrode taken out was immersed in the LiCl-added lime water A of Synthesis Example 1 or the LiF-added lime water A of Synthesis Example 2 in an argon flow container at 22 to 25° C. to generate gas for evaluation. At this time, the volume of the gas generated in 1 hour was measured, and the gas in the collection tube was analyzed using gas chromatography (GC-8A, manufactured by Shimadzu Corporation), oxygen gas, hydrogen gas, nitrogen gas. Concentration was measured. In addition, the immersed positive electrode was analyzed by X-ray diffraction (XRD) and high frequency inductively coupled plasma (ICP) to evaluate the reaction amount of intercalation of lithium ions to the positive electrode. As an example, the results of gas chromatography in Example 1 are shown in FIG.

As a result, generation of hydrogen gas was detected, but trace amounts of oxygen gas and nitrogen gas were also detected. Since nitrogen gas was detected, in subsequent tests, evaluation was performed by correcting the count number of oxygen gas derived from atmospheric mixing. The results are shown in Table 3.

Examples 3-6 and Comparative Examples 1-2 (immersion potential in the presence of halide ions)
When the lithium ion secondary battery is immersed in lime water, assuming that the change in the amount of lithium in the positive electrode is ΔX _Li ,
Oxidation reaction:
(1) 4OH ⁻ → O ₂ + 2H ₂ O + 4e
(2) Al + 3OH ⁻ → Al(OH) ₃ + 3e
Reduction reaction:
(3) Li _0.23 Ni _0.86 Co _0.14 O ₂ + ΔX _Li Li ⁺⁺ ΔX _Li e
→ Li _{0.23 + ΔX Li} Ni _0.86 Co _0.14 O ₂
(4) 2H ₂ O + 2e → H ₂ + 2OH ^-
is assumed, and the above oxidation and reduction reactions are assumed to be in balance.

A hypothetical polarization curve for each reaction in LiCl-added lime water is shown in FIG. 11, and a hypothetical polarization curve for each reaction in LiF-added lime water is shown in FIG.

When LiCl is added to lime water, it is assumed that aluminum oxidation and hydrogen generation, that is, the reactions of (2) and (4) mainly proceed, oxygen gas is not generated, and the immersion potential of the positive electrode is almost It is assumed to be between -2.28 and -0.73V in time.

On the other hand, when LiF is added to the aqueous solution, it is assumed that aluminum oxidation, intercalation and oxygen generation, that is, the reactions (1) to (3) mainly proceed, and the generation of oxygen gas can be completely suppressed. Although not necessarily, it is possible to suppress the amount generated, and it is assumed that the immersion potential of the positive electrode is 0.48 V or higher most of the time.

Therefore, the immersion potential of the positive electrode in lime water containing lithium salt was measured. Example 3 uses the LiCl-added lime water A of Synthesis Example 1, Example 4 uses the LiF-added lime water A of Synthesis Example 2, and Example 5 uses the LiCl-added lime water B of Synthesis Example 3. 6, the LiF-added lime water B of Synthesis Example 4 was used, the LiOH-added lime water of Synthesis Example 5 was used in Comparative Example 1, and the CH ₃ COOLi-added lime water of Synthesis Example 6 was used in Comparative Example 2. The apparatus shown was used to measure the immersion potential of the positive electrode in lime water containing lithium salt.

In a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume), remove the resin outer casing of the lithium-ion secondary battery, and remove a part of the casing so as not to damage the internal lithium-ion secondary battery. The positive electrode (3×10 cm ² , about 1 to 2 g, aluminum foil coated with positive electrode material Li _0.23 Ni _0.86 Co _0.14 O ₂ on both sides) was taken out.

Next, in a container in a nitrogen atmosphere, while checking the temperature with a thermocouple, at 25 ° C., the extracted positive electrode was sandwiched between alligator terminals, LiCl-added lime water A of Synthesis Example 1, LiF-added lime of Synthesis Example 2. It was immersed in water A, LiCl-added lime water B of Synthesis Example 3, LiF-added lime water B of Synthesis Example 4, LiOH-added lime water of Synthesis Example 5, or CH ₃ COOLi-added lime water of Synthesis Example 6. A platinum wire was used as the counter electrode, and a silver/silver chloride electrode (3.33 mol/L KCl) was used as the reference electrode. The potential of the electrode against was recorded to evaluate the redox potential in the immersion liquid. In the experiment, argon bubbling was performed in advance for degassing before immersion. After starting the immersion of the positive electrode, after the bubbler was pulled out from the immersion liquid, argon was flowed in the cell.

The results are shown in Figures 14-16.

In Comparative Example 1 using the LiOH-added lime water of Synthesis Example 5, the immersion potential was nobler (higher) than the O ₂ /H ₂ O redox potential for about 130 minutes after the positive electrode was immersed. Ta. For this reason, it is assumed that oxygen gas is generated for about 130 minutes after the positive electrode is immersed. I understand the need. About 180 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 130 to 180 minutes in order to avoid a large pH change accompanying dissolution.

In addition, in Comparative Example 2 using the CH ₃ COOLi-added lime water of Synthesis Example 6, the immersion potential was nobler (higher) than the O ₂ /H ₂ O redox potential for about 7 hours after the positive electrode was immersed. ) indicated the potential. For this reason, it is assumed that oxygen gas is generated for about 420 minutes after the positive electrode is immersed. I understand the need. When about 800 minutes have passed since the positive electrode was immersed, the aluminum current collector used in the positive electrode was dissolved, so that the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 420 to 800 minutes in order to avoid a large pH change accompanying dissolution.

On the other hand, the LiCl-added lime water A of Synthesis Example 1, the LiF-added lime water A of Synthesis Example 2, the LiCl-added lime water B of Synthesis Example 3, or the LiF-added lime water B of Synthesis Example 4 were used. In 3 to 6, the immersion potential decreased in a short time after the positive electrode was immersed.

Specifically, in the case of LiF-added lime water with a low fluoride ion concentration (Example 6), the immersion potential was lower than the O ₂ /H ₂ O redox potential for about 22 minutes after the positive electrode was immersed. Since a noble (high) potential was exhibited, it can be understood that immersion for 22 minutes or longer is necessary for safely deactivating the lithium ion secondary battery. About 42 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 22 to 42 minutes in order to avoid a large pH change accompanying dissolution.

In addition, in the case of LiF-added lime water with a high fluoride ion concentration (Example 4), the immersion potential was nobler than the O ₂ /H ₂ O redox potential for about 11 minutes after the positive electrode was immersed ( high) potential, it can be understood that the lithium ion secondary battery needs to be immersed for 11 minutes or more in order to deactivate safely. However, about 13 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 11 to 13 minutes in order to avoid a large pH change accompanying dissolution.

On the other hand, in the case of LiCl-added lime water (Examples 3 and 5), regardless of whether the chloride ion concentration is high or low, about 1 minute after the positive electrode is immersed, the immersion potential is O ₂ /H ₂ O Since the potential was less base (lower) than the oxidation-reduction potential, it can be understood that the positive electrode of the lithium ion secondary battery should be immersed for 1 minute or more in order to safely deactivate it. However, about 13 to 15 minutes after the positive electrode is immersed, the aluminum current collector used in the positive electrode dissolves, making the immersion potential lower than the H ₂ O/H ₂ redox potential. ), it can be understood that the immersion time is preferably 1 to 13 minutes in order to avoid a large pH change accompanying dissolution. However, since the deactivation of the negative electrode requires immersion for 10 minutes, it can be understood that the immersion time is preferably 10 to 13 minutes for deactivation as a lithium ion secondary battery.

Examples 7-10 and Comparative Examples 1-2 (immersion potential in the presence of a reducing agent)
When the lithium ion secondary battery is immersed in lime water, assuming that the change in the amount of lithium in the positive electrode is ΔX _Li ,
Oxidation reaction:
(1) 4OH ⁻ → O ₂ + 2H ₂ O + 4e
(2) Al + 3OH ⁻ → Al(OH) ₃ + 3e
Reduction reaction:
(3) Li _0.23 Ni _0.86 Co _0.14 O ₂ + ΔX _Li Li ⁺⁺ ΔX _Li e
→ Li _{0.23 + ΔX Li} Ni _0.86 Co _0.14 O ₂
(4) 2H ₂ O + 2e → H ₂ + 2OH ^-
is assumed, and the above oxidation and reduction reactions are assumed to be in balance.

However, assuming that the positive electrode is peeled off from the aluminum foil or that the aluminum is not oxidized, such as after the aluminum foil has completely melted, oxygen gas may be generated, hydrogen gas may ignite, or explode. concerns are considered. In the present invention, it is assumed that the addition of a reducing agent to the system suppresses the generation of oxygen gas even when aluminum is not oxidized sacrificially.

A potential-pH diagram for the I—H ₂ O system is shown in FIG. 17 for thermodynamic studies. Assuming that lime water is used as the alkaline aqueous solution, the pH of lime water is approximately 12.5, so the behavior at pH 12.5 will be examined. At a pH of 12.5, from FIG. 16, the redox potential of O ₂ /H ₂ O is 0.49 V vs SHE (point A), and the redox potential of IO ₃ ⁻ /I ⁻ is 0.36 V. vs SHE (point B). Then, when an iodide ion (I ⁻ ) is contained as a reducing agent, the redox potential of IO ₃ ⁻ /I ⁻ is less noble (lower) than the redox potential of O ₂ /H ₂ O. Because of the potential, the oxidation reaction of iodide ions (I ⁻ ) takes precedence over the oxygen generation reaction, and the generation of oxygen gas can be suppressed. That is, as the reducing agent, a substance capable of causing an oxidation reaction having an oxidation-reduction potential that is less noble (lower) than the oxidation-reduction potential of O ₂ /H ₂ O at the pH of the aqueous solution can be used.

To confirm the results, the immersion potential of the positive electrode in lime water containing lithium salt was measured. Example 7 uses the LiI-added lime water of Synthesis Example 7, Example 8 uses the thiourea and CH ₃ COOLi-added lime water of Synthesis Example 8, and Example 9 uses ascorbic acid and CH ₃ COOLi of Synthesis Example 9. Using lime water, Example 10 uses ascorbic acid, CH ₃ COOLi and LiOH-added lime water of Synthesis Example 10, Comparative Example 1 uses LiOH-added lime water of Synthesis Example 5, and Comparative Example 2 uses LiOH-added lime water of Synthesis Example 6. Using CH ₃ COOLi-added lime water, the immersion potential of the positive electrode in lime water containing lithium salt was measured by the apparatus shown in FIG.

In a glove box in a nitrogen atmosphere (oxygen concentration: less than 1% by volume), remove the resin outer casing of the lithium-ion secondary battery, and remove a part of the casing so as not to damage the internal lithium-ion secondary battery. The positive electrode (3×10 cm ² , about 1 to 2 g, aluminum foil coated with positive electrode material Li _0.23 Ni _0.86 Co _0.14 O ₂ on both sides) was taken out.

Then, in a container in a nitrogen atmosphere, while confirming the temperature with a thermocouple, at 25 ° C., the extracted positive electrode was sandwiched between alligator terminals, LiI-added lime water of Synthesis Example 7, thiourea and CH of Synthesis Example 8 ₃ COOLi-added lime water, ascorbic acid and CH ₃ COOLi-added lime water of Synthesis Example 9, ascorbic acid, CH ₃ COOLi and LiOH-added lime water of Synthesis Example 10, LiOH-added lime water of Synthesis Example 5, or Synthesis Example 6 It was immersed in CH ₃ COOLi-added lime water. A platinum wire was used as the counter electrode, and a silver/silver chloride electrode (3.33 mol/L KCl) was used as the reference electrode. The potential of the electrode against was recorded to evaluate the redox potential in the immersion liquid. In the experiment, argon bubbling was performed in advance for degassing before immersion. After starting the immersion of the positive electrode, after the bubbler was pulled out from the immersion liquid, argon was flowed in the cell.

The results of the immersion potential of Example 7 using the LiI-added lime water of Synthesis Example ₇ are shown in FIG. FIG. 20 shows the results of the immersion potential of Example 9 using the thiourea and CH ₃ COOLi-added lime water of Synthesis Example 9, and the ascorbic acid, CH ₃ COOLi and LiOH-added lime water of Synthesis Example 10. FIG. 21 shows the immersion potential results for Example 10 using . The immersion potential results of Comparative Example 1 using the LiOH-added lime water of Synthesis Example 5 and Comparative Example 2 using the CH ₃ COOLi-added lime water of Synthesis Example 6 are shown in FIGS.

In Comparative Example 1 using the LiOH-added lime water of Synthesis Example 5, the immersion potential was nobler (higher) than the O ₂ /H ₂ O redox potential for about 130 minutes after the positive electrode was immersed. Ta. For this reason, it is assumed that oxygen gas is generated for about 130 minutes after the positive electrode is immersed. I understand the need. About 180 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 130 to 180 minutes in order to avoid a large pH change accompanying dissolution.

In addition, in Comparative Example 2 using the CH ₃ COOLi-added lime water of Synthesis Example 6, the immersion potential was nobler (higher) than the O ₂ /H ₂ O redox potential for about 7 hours after the positive electrode was immersed. ) indicated the potential. For this reason, it is assumed that oxygen gas is generated for about 7 hours after the positive electrode is immersed. I understand the need. About 13 hours after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, so that the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 7 to 13 hours in order to avoid a large pH change accompanying dissolution.

In Comparative Examples 1 and 2, the potential is kept noble (high) due to the intercalation reaction of lithium ions, and oxygen gas continues to be generated for a long time. , it can be understood that long-term immersion is required.

On the other hand, Example 7 using the LiI-added lime water of Synthesis Example 7, Example 8 using the thiourea and CH ₃ COOLi-added lime water of Synthesis Example 8, and ascorbic acid and CH ₃ COOLi of Synthesis Example 9 were added. In Example 9 using lime water and Example 10 using ascorbic acid, CH ₃ COOLi and LiOH-added lime water of Synthesis Example 10, the immersion potential decreased in a short time after the positive electrode was immersed.

Specifically, in the case of LiI-added lime water (Example 7), the immersion potential was lower than the O ₂ /H ₂ O redox potential within 1 minute (around 15 seconds) after the positive electrode was immersed. It can be understood that immersion for 15 seconds or longer is sufficient to deactivate the positive electrode of the lithium ion secondary battery safely. However, about 130 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 15 seconds to 130 minutes in order to avoid a large pH change accompanying dissolution. However, since the deactivation of the negative electrode requires immersion for 10 minutes, it can be understood that the immersion time is preferably 10 to 130 minutes for deactivation as a lithium ion secondary battery.

In addition, in the case of thiourea and CH ₃ COOLi-added lime water (Example 8), the immersion potential was lower (lower) than the O ₂ /H ₂ O redox potential 4 minutes after the positive electrode was immersed. Since the potential was shown, it can be understood that thiourea functions effectively as a reducing agent, and that immersion for 4 minutes or more is sufficient for safely deactivating the positive electrode of the lithium ion secondary battery. However, about 350 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a more base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 4 to 350 minutes in order to avoid a large pH change accompanying dissolution. However, since the deactivation of the negative electrode requires immersion for 10 minutes, it can be understood that the immersion time is preferably 10 to 350 minutes for deactivation as a lithium ion secondary battery. In the case of using thiourea, it can be seen that a two-step reaction occurs, probably because the exposure of the aluminum current collector in the positive electrode is small, and the immersion potential is higher than the O ₂ /H ₂ O redox potential. After exhibiting a base (low) potential, it took a long time to transition to a base (lower) potential than the H ₂ O/H ₂ redox potential. Further, from FIG. 19, since the potential of the platinum electrode is stable around -0.3 V, it is suggested that the equilibrium potential of the oxidation-reduction reaction in which thiourea is oxidized is about -0.3 V. .

In addition, in the case of ascorbic acid and CH ₃ COOLi-added lime water (Example 9), the immersion potential was lower (lower) than the O ₂ /H ₂ O redox potential at 0 minutes after the positive electrode was immersed. Ascorbic acid functions effectively as a reducing agent, and it can be understood that immersion for 0 minutes or longer is sufficient to safely deactivate the positive electrode of the lithium ion secondary battery. In addition, even if 20 hours or more have passed since the positive electrode was immersed, the immersion potential does not change to a potential less noble (lower) than the H ₂ O/H ₂ oxidation-reduction potential, so a significant change in pH due to dissolution is avoided. Therefore, it can be understood that the immersion time can be appropriately adjusted from 0 minutes or more. However, since 10 minutes of immersion is required to deactivate the negative electrode, it can be understood that the immersion time can be appropriately adjusted from 10 minutes or more for deactivation as a lithium ion secondary battery. Note that FIG. 20 suggests that the equilibrium potential of ascorbic acid and its oxidant is about 0V because the potential of the platinum electrode is stable around 0V.

In the case of ascorbic acid, CH ₃ COOLi, and LiOH-added lime water (Example 10), the immersion potential was lower than the O ₂ /H ₂ O redox potential 7 minutes after the positive electrode was immersed ( (low) potential, it can be understood that ascorbic acid functions effectively as a reducing agent, and that immersion for 7 minutes or more is sufficient for safely deactivating the positive electrode of the lithium ion secondary battery. . However, about 13 minutes after the positive electrode was immersed, the aluminum current collector used in the positive electrode dissolved, and the immersion potential became a base (lower) potential than the H ₂ O/H ₂ redox potential. , it can be understood that the immersion time is preferably 7 to 13 minutes in order to avoid a large pH change accompanying dissolution. However, since the deactivation of the negative electrode requires immersion for 10 minutes, it can be understood that the immersion time is preferably 10 to 13 minutes for deactivation as a lithium ion secondary battery. From FIG. 21, it can be seen that the potential of the platinum electrode is stable around −0.3 V before the generation of hydrogen gas, so the equilibrium potential between ascorbic acid and the oxidant of ascorbic acid is approximately −0.3 V. Something is suggested.

As in the results of Comparative Examples 1 and 2 above, the intercalation reaction of lithium ions keeps the potential noble (high) and oxygen gas continues to be generated for a long time. Despite the presence of lithium ions, the presence of halide ions and reducing agents suppresses the intercalation reaction of lithium ions and suppresses the generation of oxygen gas. It is envisioned that shorter immersion times may be possible for safe quenching.

In order to confirm this, Example 7 using the LiI-added lime water of Synthesis Example 7 and Example 8 using the thiourea and CH ₃ COOLi-added lime water of Synthesis Example 8 were carried out in the same manner as in Examples 1 and 2. , Example 10 using ascorbic acid, CH ₃ COOLi and LiOH-added lime water of Synthesis Example 10, and Comparative Example 2 using CH ₃ COOLi-added lime water of Synthesis Example 6, the amount of gas generated during immersion of the positive electrode was measured by gas chromatography. However, during the measurement, gas chromatography detected not only hydrogen gas and oxygen gas, but also nitrogen gas. Nitrogen gas is detected when it is mixed with air. Therefore, the count number of oxygen gas was corrected according to the count number of nitrogen gas, and the result that minimized the influence of the mixture of air was calculated. The results are shown in Table 4.

From Table 4, compared with Comparative Example 2, in Examples 7, 8 and 10, the amount of oxygen gas generated was extremely small or no oxygen gas was generated, and the lithium ion secondary battery was safely deactivated. It has been suggested that it is possible.

REFERENCE SIGNS LIST 1 chamber 2 sample stage 3 blade 4 rotating rod 5 drop lid

Claims (21)

A method for deactivating a lithium ion secondary battery, comprising:
(1) comprising a step of immersing the lithium ion secondary battery in an aqueous solution containing halide ions and/or a reducing agent;
The reducing agent is a reductant (Red) having a redox pair (Ox/Red) with a standard redox potential lower than the standard redox potential of O ₂ /H ₂ O at the pH of the aqueous solution. . 2. The method of claim 1, wherein said aqueous solution is in an alkaline aqueous solution. 2. The method according to claim 1, wherein said halide ion is at least one selected from the group consisting of chloride ion, bromide ion and iodide ion. 4. The method according to claim 1 or 3, wherein the halide ion concentration is from 1.00×10 ⁻⁵ to 3.0 mol/L. 2. The method according to claim 1, wherein the reducing agent is at least one selected from the group consisting of iodide ions, sulfur-based oxoacid ions, urea compounds, phosphorus-based oxoacid ions, and organic acids. 6. The method according to claim 1 or 5, wherein the reducing agent has a concentration of 1.00×10 ⁻⁵ to 3.0 mol/L. 6. The method according to claim 1, 3 or 5, wherein step (1) is performed under an inert gas atmosphere or a reducing gas atmosphere. 6. The method of claim 1, 3 or 5, wherein in step (1), the aqueous solution is a solution of an alkaline earth metal compound. The method according to claim 8, wherein the alkaline earth metal compound has a concentration of 1.00×10 ⁻⁵ to 3.0 mol/L. 6. The method of claim 1, 3 or 5, wherein in step (1), the aqueous solution is lime water. After the step (1),
(2) The method according to claim 1, 3 or 5, comprising the step of opening the lithium ion secondary battery in the aqueous solution. 12. The method of claim 11, wherein step (2) is performed under an inert gas atmosphere or a reducing gas atmosphere. The step of opening the lithium ion secondary battery includes crushing or cutting the lithium ion secondary battery, making a hole penetrating the casing of the lithium ion secondary battery, or the casing of the lithium ion secondary battery. 12. The method of claim 11, wherein the step of partially or fully unpacking. 12. The method according to claim 11, wherein in step (2), after opening the lithium ion secondary battery, the lithium ion secondary battery is immersed in an aqueous solution for 10 minutes or longer. After the step (2),
(3) The method according to claim 11, comprising the step of drying the deactivated lithium-ion secondary battery. A method for separating and recovering metal elements from a lithium ion secondary battery,
12. A method comprising, after deactivating a lithium ion secondary battery by the method according to claim 11, pulverizing and physically sorting the deactivated lithium ion secondary battery. A lithium ion secondary battery deactivation device used for deactivating a lithium ion secondary battery,
a chamber in which an aqueous solution containing halide ions and/or a reducing agent is stored;
A mechanism for opening a lithium ion secondary battery placed in the chamber and placed in the chamber,
The reducing agent is a reductant (Red) having a redox pair (Ox/Red) with a standard redox potential lower than the standard redox potential of O ₂ /H ₂ O at the pH of the aqueous solution. Ion secondary battery deactivation device. an openable/closable lid placed on the chamber for isolating a closed space formed above the aqueous solution from the outside;
18. The lithium ion secondary battery deactivation device according to claim 17, further comprising a gas supply unit that supplies inert gas or reducing gas to said closed space. A vehicle comprising the lithium ion secondary battery deactivation device according to claim 17 or 18. A portable plant comprising the lithium ion secondary battery deactivation device according to claim 17 or 18. A lithium ion secondary battery recycling method using the method according to claim 1, 3 or 5.

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