KR20190036644A - Electrolysis for recycling battery, and method of recycling battery using the same - Google Patents

Abstract

The present invention relates to an electrolyte for regenerating wasted batteries, and a method for regenerating wasted batteries using the same. The electrolyte for regenerating wasted batteries comprises: an electrolyte comprising a non-aqueous organic solvent and a lithium salt; and a wasted batter regenerating additive. The wasted battery regenerating additive is lithium nitrate, vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sultone, unsaturated sultone, acyclic sulfone, or a combination thereof. According to the present invention, the performance of a positive/negative electrode active material can be restored so that the wasted batteries can be regenerated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrolyte for regenerating a waste battery, and a method for recycling a waste battery using the same. BACKGROUND ART [0002]

An electrolyte for regenerating a spent cell, and a method for recycling a used cell using the same.

More specifically, an electrode capable of recovering performance is injected into a waste battery whose voltage and current values are lower than the standard due to long-time discharge or damage to the electrode plate, thereby regenerating the electrode plate and normalizing the ionization reaction, To an electrolyte and a method capable of regenerating a discharge function.

In recent years, the explosion of electric vehicles using lithium secondary batteries has led to an increase in the number of used batteries that have reached the end of their life.

An electric vehicle battery is composed of several packs, and the pack is composed of several cells. The cell is divided into two cases, one using a square or pouch type cell and the other using a cylindrical cell such as the 18650 cell.

Each cell is composed of an anode and a cathode, a separator, and an electrolyte. A material capable of reversible intercalation / deintercalation of lithium ions is used as a cathode and an anode active material, and a separator is formed between the anode and the cathode. It is manufactured by filling the electrolyte.

When a short circuit occurs in a two-electrode plate during a long period of charging and discharging cycles, or when a SEI layer is thickly formed in an active material, a battery of an automobile may be depleted of electrolyte or may be exposed to a variety of local electronic structures such as impurities (metals, If the charging and discharging functions are not performed smoothly due to the cause, it is necessary to replace it at the end of its life.

The life of the battery in an electric vehicle is considered to have reached the end of its useful life when it has dropped to 80% of its initial capacity. It is a reality that it is necessary to develop a technique of extending the life of the battery by reusing or regenerating the remaining capacity of 80%.

We propose a method of recovering a waste battery whose voltage and / or current value is below the standard due to long discharge or damage of the electrode plate.

In one embodiment of the present invention, there is provided a nonaqueous organic solvent, and an electrolyte comprising the lithium salt and a recycle additive for a waste battery, wherein the recycle additive for waste battery is selected from the group consisting of lithium nitrate, vinylene carbonate, Wherein the electrolytic solution is a carbonate, a fluoroethylene carbonate, a cyclic sulfite, a saturated sulphone, an unsaturated sulphone, a non-cyclic sulphone, or a combination thereof.

The recycling additive for waste batteries may be contained in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the non-aqueous organic solvent. The range may be effective for removing the SEI layer on the electrode active material surface. As a result, the capacity of the battery can be largely restored.

More specifically, the spent cell regeneration additive may include lithium nitrate, vinylene carbonate, saturated sulphone, and cyclic sulfite. A combination of specific additives can effectively remove the SEI layer.

The non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, aprotic solvent or a combination thereof.

These organic solvents are examples of currently commercially used solvents, and the present invention is not limited thereto.

However, organic solvents can be selected depending on combinations with specific additives, and such combinations are not yet known.

For example, the carbonate-based solvent is selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC) , Ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), or a combination thereof.

For example, the lithium salt may be LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiC ₄ F ₉ SO ₃ , LiClO ₄ , LiAlO ₂ , LiAlCl ₄ , LiN (C _x F _{2x + 1} SO ₂ ) C _y F _{2y + 1} SO ₂ wherein x and y are natural numbers, LiCl, LiI, LiB (C ₂ O ₄ ) ₂ (lithium bis (oxalato) borate (LiBOB) Or a combination thereof.

The concentration of the lithium salt may be 0.1 to 2M in the electrolyte. Which may be the concentration required for commercial batteries at the present time.

According to another embodiment of the present invention, there is provided a method for preparing a waste battery, comprising the steps of preparing a waste battery, removing waste electrolytes and other impurities in the waste battery, and injecting and regenerating the waste electrolyte with a new electrolyte and a waste battery recycle additive, The recycling additive for waste batteries may be recycled as waste battery recycling method which is lithium nitrate, vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sulphone, unsaturated sulphone, acyclic sulphone, Can be provided.

The step of removing the waste electrolytes and other impurities in the waste battery may be performed in a dry room or an inert atmosphere.

Or removing the waste electrolytes and other impurities in the waste battery may be performed under vacuum conditions. A detailed description thereof will be given later.

The step of injecting and regenerating the new electrolyte and the recycle additive for recycling the battery may include a method of introducing a fresh electrolyte and a recycle additive for recycling the battery into the waste battery and then applying a vibration at a predetermined temperature. To 50 < 0 > C.

This will be described in a specific embodiment to be described later.

According to the method for recycling a spent battery according to an embodiment of the present invention as described above, an electrolyte containing an additive is injected into a closed cell to eliminate the shortage of electrolyte due to long-term use of the battery, And the waste battery can be regenerated.

1 is a cell characteristic data according to an embodiment.
FIG. 2 is battery characteristic data according to one comparative example.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

Generally, if the battery is used for a long time, a short circuit occurs in the two electrode plates in the course of repeated charging and discharging cycles, or a thick SEI layer is formed in the active material. In addition, charging and discharging functions may not be performed smoothly due to various causes such as depletion of the electrolyte or local electronic structure due to impurities (metal, gas, etc.) in the electrolyte. In this case, the battery will not be able to meet the specified capacity and the battery will have to be replaced.

In one embodiment of the present invention, after the spent battery is completely discharged, the pack is separated and separated into individual cells. Then, holes are made in each cell in the drainer environment, and the existing electrolyte and generated gas and impurities are removed by vacuum.

Then, an electrolyte containing an additive capable of restoring performance is injected into the cell, and holes are closed to replenish the depleted electrolyte for various reasons, and to regenerate the performance of the anode / anode active material.

As a result, the capacity of the waste battery can be restored and the waste battery can be reused.

More specifically, the regeneration process of such a waste battery will be described.

In the case of waste batteries used for electric vehicles, there is a high risk of explosion and fire in a charged state. Therefore, it is necessary to completely discharge the charged electric current and then to separate the battery pack and separate it into individual cells.

Each discharged cell evaluates the charging capacity and the discharging capacity by using a charge / discharge device, and classifies it according to the capacity.

For example, the cells are divided into cells having a capacity of 80% or more, 68% to 80%, or 68% or less. Cells having a capacity of 68% or less are subjected to a regeneration process.

The cells with reduced capacity are made completely discharged, and then holes are made in each cell in a dry room or an inert atmosphere, and vacuum is used to remove existing electrolytes and generated gases and impurities.

Thereafter, an electrolyte containing an additive capable of restoring performance is injected into the cell and the hole is blocked. Thereafter, the cell is shaken at a constant temperature (25 to 50 ° C) for a certain period of time to uniformly distribute the electrolyte, thereby activating the anode / anode active material and increasing the activity of the Li ion.

The electrolyte used in one embodiment of the present invention can be used in a concentration range of 0.1 M to 2.0 M, more preferably in a range of 0.7 M to 1.6 M, in the lithium salt.

If the concentration of the lithium salt is less than 0.1 M, the conductivity of the electrolyte may be lowered and the performance of the electrolyte may be deteriorated. On the other hand, if the concentration exceeds 2.0 M, the viscosity of the electrolyte may increase and the lithium ion mobility may decrease.

The lithium salt is dissolved in an organic solvent to act as a source of lithium ions in the cell to enable operation of a basic lithium secondary battery and to promote the movement of lithium ions between the anode and the cathode. The lithium salt Representative examples are _{LiPF 6, LiBF 4, LiSbF 6} , LiAsF 6, LiC 4 F 9 SO 3, LiClO 4, LiAlO 2, LiAlCl 4, LiN (C x F 2x + 1 SO 2) (C y F 2y ₊₁ SO ₂₎ (where, x and y are natural numbers), LiCl, LiI, and _{LiB (C 2 O 4) 2} ( lithium bis oxalate reyito borate (lithium bis (oxalato) borate; LiBOB) is selected from the group consisting of The concentration of the lithium salt is preferably in the range of 0.1 to 2.0 M. When the concentration of the lithium salt is within the above range, the electrolyte has appropriate conductivity and viscosity Can exhibit excellent electrolyte performance, and lithium ions can effectively migrate.

The non-aqueous organic solvent serves as a medium through which ions involved in the electrochemical reaction of the battery can move.

The non-aqueous organic solvent may be a carbonate, ester, ether, ketone, alcohol, or aprotic solvent. Examples of the carbonate solvent include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC) EC), propylene carbonate (PC), and butylene carbonate (BC) may be used. As the ester solvent, methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate ,? -butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone, and the like can be used. Examples of the ether solvent include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, and tetrahydrofuran. As the ketone solvent, cyclohexanone may be used have. As the alcoholic solvent, ethyl alcohol, isopropyl alcohol and the like can be used. As the aprotic solvent, R-CN (R is a linear, branched or cyclic hydrocarbon group having 2 to 20 carbon atoms, , A double bond aromatic ring or an ether bond), and dioxolanes such as 1,3-dioxolane, sulfolanes, and the like can be used.

The non-aqueous organic solvent may be used alone or in admixture of one or more. If the non-aqueous organic solvent is used in combination, the mixing ratio may be appropriately adjusted according to the desired cell performance. .

In the case of the carbonate-based solvent, it is preferable to use a mixture of a cyclic carbonate and a chain carbonate. In this case, when the cyclic carbonate and the chain carbonate are mixed in a volume ratio of 1: 1 to 1: 9, the performance of the electrolyte may be excellent.

The non-aqueous organic solvent according to an embodiment of the present invention may further include an aromatic hydrocarbon-based organic solvent in the carbonate-based solvent. In this case, the carbonate-based solvent and the aromatic hydrocarbon-based organic solvent may be mixed in a volume ratio of 1: 1 to 30: 1.

The aromatic hydrocarbon-based organic solvent may be an aromatic hydrocarbon-based compound represented by the following formula (1).

[Chemical Formula 1]

(Wherein R ₁ to R ₆ are each hydrogen, a halogen, a C ₁ to C 10 alkyl group, a haloalkyl group, or a combination thereof)

The aromatic hydrocarbon-based organic solvent is selected from the group consisting of benzene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3- , 1,2,4-trifluorobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 4-trichlorobenzene, iodobenzene, 1,2-diiodobenzene, 1,3-diiodobenzene, 1,4-diiodobenzene, 1,2,3-triiodobenzene, 1,2,4 - triiodobenzene, toluene, fluorotoluene, 1,2-difluorotoluene, 1,3-difluorotoluene, 1,4-difluorotoluene, 1,2,3-trifluorotoluene, 1,2,4-trifluorotoluene, chlorotoluene, 1,2-dichlorotoluene, 1,3-dichlorotoluene, 1,4-dichlorotoluene, 1,2,3-trichlorotoluene, 1,2,4 - trichlorotoluene, iodotoluene, 1,2-diiodotoluene, 1,3-diiodotoluene, 1,4-diiodotol Yen, it is 1,2,3-tree-iodo toluene, 1,2,4-iodo toluene, xylene, and selected from the group consisting of.

The non-aqueous electrolyte may further include vinylene carbonate or an ethylene carbonate-based compound represented by the following formula (2) to improve battery life.

(2)

(In Formula 2, R ₇ and R ₈ are each hydrogen, a halogen group, a cyano group (CN), nitro group (NO ₂₎ or a C1 to a to C5 fluoroalkyl group, at least one of the R ₇ and R ₈ is a halogen A cyano group (CN), a nitro group (NO ₂ ), or a C1 to C5 fluoroalkyl group.

Representative examples of the ethylene carbonate-based compound include diethylene carbonate, diethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, fluoroethylene carbonate, and the like, such as difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, . When such a life improving additive is further used, its amount can be appropriately adjusted.

In one embodiment of the present invention, recycle additive for lithium secondary battery is lithium nitrate, vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sulphone, unsaturated sulphone, May be used alone or in admixture of two or more. However, the present invention is not limited thereto and conventionally known additives may be further included within the scope of the present invention.

Examples of the cyclic sulfite include ethylene sulfite, methyl ethylene sulfite, ethyl ethylene sulfite, 4,5-dimethylethylene sulfite, 4,5-diethyl ethylene sulfite, propylene sulfite, Diethyl propyl sulfite, 4,6-diethyl propyl sulfite, and 1,3-butylene glycol sulfite. The saturated sulphone includes, for example, 1,3-propane sultone, and 1,4-butane sultone. Examples of the unsaturated sultone include ethene sultone, 1,3-propene sultone, 1,4-butene sultone, Phenolsaltone, and the like. Examples of the non-cyclic sulfone include divinyl sulfone, dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone, and methyl vinyl sulfone.

The additive may be contained in an appropriate amount depending on the specific kind of additive, for example, 0.01 to 5 parts by weight based on 100 parts by weight of the electrolyte.

Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are only illustrative of the present invention and are not intended to limit the scope of the present invention.

Example

Cell preparation

The cell used in this embodiment is a cell manufactured by Enertech, and the specifications are as follows.

The cell used in this evaluation was a battery pack operated on an e-BUS electric bus, and the module was disassembled and separated into unit cells, and the cell capacity was evaluated. Based on the discharge capacity, A grade (14.0 Ah or more, 80% Grade (13.9Ah ~ 12.0Ah, 68% ~ 80%) and grade C (less than 12Ah, less than 68%).

Cells classified as C are discharged to 2.5 V by 0.5 C discharge and then pierced with a syringe in a cell in an inert atmosphere environment in a drier or glove box and sucked in vacuum to remove the existing electrolyte and generated gases and impurities .

Preparation of electrolyte

First, additives were added to 100 parts by weight of a 3: 3: 4 volume ratio mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and methyl carbonate (DMC).

0.5 parts by weight of lithium nitrate, 1.5 parts by weight of vinylene carbonate (VC), 0.5 parts by weight of 1,3-propane sultone (PS) and 1 part by weight of ethylene sulfate (Esa) were used as additives.

LiPF ₆ , a lithium salt, was added thereto to dissolve LiPF ₆ to a concentration of 1.0 M to prepare an electrolyte.

Cell reassembly and cell activation

The prepared electrolyte was injected using a syringe. After sealing the hole, agitation was performed by vibrating the left and right sides maintained at a temperature of 25 to 30 ° C, followed by agitation with a constant current of 0.1 C (2.1 A) And then charged to 4.2 V constant-voltage charge to a current value of 0.01 C (0.21 A).

Cell evaluation result

As a result of evaluating the constant current discharge capacity at the current value of 0.1C (2.1A) in the range of 3.0 ~ 4.2V using the charging / discharging device, the discharge capacity was recovered to the capacity of 14.6Ah at the capacity of 6.6Ah. (See Fig. 1)

Comparative Example

Except that a nonaqueous electrolyte containing 1M LiPF ₆ was used in a 3: 3: 4 volume ratio mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and methyl carbonate (DMC) Was carried out in the same manner as in Example.

As a result of the evaluation of the cell, the discharging capacity was increased to 10.3 Ah at the capacity of 6.5 Ah, but the capacity was not recovered. (See Fig. 2)

The present invention solves the problem of electrolyte shortage due to the use of the battery for a long time by injecting the electrolyte containing the additive and shakes the cell for a predetermined time while heating the cell to a predetermined temperature, thereby uniformly distributing the electrolyte, And plays a role of recovering the capacity of the battery by activating the negative electrode active material and increasing the activity of Li ion.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (12)

An electrolyte comprising a non-aqueous organic solvent, and a lithium salt; And
A waste battery recycling additive,
Wherein the spent cell regeneration additive is at least one selected from the group consisting of lithium nitrate, vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sulphone, unsaturated sulphone, acyclic sulphone, Electrolytes for regeneration.
The method according to claim 1,
The recycling additive for waste batteries may contain,
And 0.01 to 5 parts by weight based on 100 parts by weight of the non-aqueous organic solvent.
The method according to claim 1,
Wherein the waste battery recycle additive comprises lithium nitrate, vinylene carbonate, saturated sulphone, and cyclic sulfite.
The method according to claim 1,
Wherein the non-aqueous organic solvent is a carbonate, ester, ether, ketone, alcohol, aprotic solvent, or a combination thereof.
5. The method of claim 4,
The carbonate-based solvent is selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC) ), Propylene carbonate (PC), butylene carbonate (BC), or a combination thereof.
The method according to claim 1,
The lithium _{salt, LiPF 6, LiBF 4, LiSbF} 6, LiAsF 6, LiC 4 F 9 SO 3, LiClO 4, LiAlO 2, LiAlCl 4, LiN (C x F 2x + 1 SO 2) (C y F 2y + ₁ SO ₂ ) wherein x and y are natural numbers, LiCl, LiI, LiB (C ₂ O ₄ ) ₂ (lithium bis (oxalato) borate (LiBOB) Electrolyte for regenerating spent cells.
The method according to claim 1,
And the concentration of the lithium salt is 0.1 to 2M in the electrolyte.
Preparing a waste battery;
Removing waste electrolytes and other impurities in the waste battery; And
Injecting a fresh electrolyte and a recycle additive for a waste battery into the waste battery to regenerate the waste battery;
Lt; / RTI >
The recycling additive for waste batteries may contain,
Wherein the electrolyte is lithium nitrate, vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, cyclic sulfite, saturated sulphone, unsaturated sulphone, acyclic sulphone, or a combination thereof.
9. The method of claim 8,
Removing the waste electrolytes and other impurities in the waste battery,
Or in an inert atmosphere.
9. The method of claim 8,
Removing the waste electrolytes and other impurities in the waste battery,
Lt; RTI ID = 0.0 > vacuum < / RTI > conditions.
9. The method of claim 8,
Injecting a new electrolyte and a recycle additive for a waste battery into the waste battery,
Wherein a method for introducing a new electrolyte and a recycling additive for waste batteries into a waste battery and then applying a vibration at a predetermined temperature is used.
12. The method of claim 11,
Wherein the predetermined temperature is 20 to 50 占 폚.

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