KR20200077108A - Pretreatment method for recycling lithium secondary battery - Google Patents

Abstract

According to the present invention, a pretreatment method for a lithium secondary battery regeneration process comprises the steps of: discharging lithium secondary battery waste; shredding the discharged lithium secondary battery waste; pulverizing the shredded material; and firing the pulverized material, wherein the firing step includes a first firing step, a second firing step, and a third firing step.

Description

Pretreatment method for lithium secondary battery recycling process {PRETREATMENT METHOD FOR RECYCLING LITHIUM SECONDARY BATTERY}

The present invention relates to a pretreatment method for a lithium secondary battery regeneration process.

As technology development and demand for mobile devices increase, demand for secondary batteries as an energy source is rapidly increasing. Among them, lithium secondary batteries exhibiting high energy density and operating potential, long cycle life, and low self-discharge rate have been widely used.

A lithium secondary battery is generally composed of a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte, and charging and discharging are performed by intercalation-decalation of lithium ions. Lithium secondary batteries have a high energy density, a large electromotive force, and have the advantage of exerting a high capacity, and thus have been applied to various fields.

The positive electrode active material of a lithium secondary battery includes, along with lithium, transition metals such as nickel, manganese, and cobalt. The lithium and transition metals are relatively expensive metals. In particular, cobalt has a limited number of producers, and its supply and demand worldwide. It is known as this unstable metal. Accordingly, attempts have been made to recover and recycle the lithium and nickel, manganese, and cobalt transition metals from waste electrodes, particularly anodes.

Republic of Korea Patent Publication No. 2012-0126946 relates to a pre-treatment method for the regeneration process of a lithium ion battery, (1) lithium ion battery waste containing electrolyte, separator, electrode composite and current collector, the size of 5 to 15 mm Crushing with; (2) after washing the lysate with water to remove the electrolyte, removing the separator by non-separating the lysate from which the electrolyte has been removed; And (3) treating the crushed material from which the electrolyte and the separator have been removed with a sulfuric acid solution having a concentration of 1 to 4M, and recovering the electrode composite attached to the current collector among the crushed material by peeling it away from the current collector to recover the lithium ion battery. Disclosed are the contents of the pretreatment method.

Republic of Korea Registered Patent No. 1,830,309 relates to a method for processing the battery firing and dust collection, and discharges the electric vehicle waste battery transferred in one direction through a closed pipe at a temperature of 400°C to 1000°C and discharges it. After heat-treating the generated gas to a temperature of 600 °C to 900 °C, and cooling and dust collecting, the cooling treatment cools the gas generated during the firing to a temperature of 150 °C to 250 °C through a heat exchanger, , It characterized in that the supply and circulation of cooling water to the end of the closed tube and the heat exchanger through the cooling tower, discloses the content of the battery firing and calcination gas treatment method.

However, in the case of the conventional pretreatment method, there is a risk of explosion when crushing, and the process of removing electrolytes, separators, current collectors, etc. is rather long, and a solvent such as sulfuric acid is used, resulting in wastewater treatment problems, or batch burning of waste batteries. Therefore, there is a problem that impurities contained in the binder and the electrolyte may be present.

Therefore, there is a need to develop a pretreatment method for a lithium secondary battery regeneration process having a shortened process and excellent productivity.

Republic of Korea Patent Publication No. 2012-0126946 (2012.11.21) Republic of Korea Registered Patent No. 1,830,309 (2018.02.12)

The present invention is to provide a pre-treatment method for a lithium secondary battery regeneration process that can shorten the conventional complex process and improve productivity.

The present invention is a step of discharging a lithium secondary battery waste; Crushing the discharged lithium secondary battery waste; Crushing the crushed crushed material; And calcining the pulverized product, wherein the calcining step provides a pretreatment method for a lithium secondary battery regeneration process including a first calcination step, a second calcination step, and a third calcination step.

The pretreatment method for a lithium secondary battery regeneration process according to the present invention has an advantage of efficiently separating and removing a separator, an electrolyte, a current collector, and an electrode composite through a firing process instead of a complicated step process.

In addition, since the lithium secondary battery regeneration process according to the present invention can be a continuous process rather than a batch process, powder loss occurring between batches can be suppressed and waste powder productivity can be improved. There is an advantage.

1 is a schematic diagram of a pretreatment method for a lithium secondary battery regeneration process according to an embodiment of the present invention.
2 is a view showing a firing profile of a pretreatment method for a lithium secondary battery regeneration process according to an embodiment of the present invention.
3 is an image after classification according to an embodiment of the present invention (left: classified separator, case, electrode plate; right: positive electrode active material).
4 is an image showing a positive electrode active material obtained through multi-stage firing according to an embodiment of the present invention.

In the present invention, when a part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

One aspect of the present invention, discharging the lithium secondary battery waste; Crushing the discharged lithium secondary battery waste; Crushing the crushed crushed material; And calcining the pulverized product, wherein the calcining step relates to a pretreatment method for a lithium secondary battery regeneration process including a first calcination step, a second calcination step, and a third calcination step.

In one embodiment of the present invention, the lithium secondary battery waste may include one or more selected from the group consisting of an electrolyte, a separator, an electrode composite, and a current collector.

In another embodiment of the present invention, the lithium secondary battery waste may include at least one of scraps generated during the production process of the waste lithium secondary battery and the lithium secondary battery.

Hereinafter, the present invention will be described by dividing it step by step with reference to FIG. 1.

Discharge phase

The pretreatment method for a lithium secondary battery regeneration process according to the present invention includes discharging a lithium secondary battery waste.

The discharge is performed in order to prevent explosion of the waste lithium battery in the future.

In another embodiment of the present invention, the discharge perforates the lithium secondary battery; Or, it may be to corrode with a discharge solution containing brine (NaCl) or distilled water.

Preferably, the discharge may be performed by drilling the lithium secondary battery by using a perforator and corroding with brine.

The time to be corroded with the discharge solution and the concentration of brine can be appropriately adjusted to minimize the amount of hydrogen gas and the amount of precipitation of hydroxide depending on the type of the lithium secondary battery.

For example, saline, such as NaCl having a concentration of 0.1% to 4.0%, is 12 hours or less at room temperature, preferably saline having a concentration of 0.3% to 2.0%, 6 hours or less at room temperature, more preferably 0.5% to 0.5% With 1.0% brine, it can be discharged by corrosion at room temperature for 4 hours or less, but is not limited thereto.

When the lithium secondary battery waste is discharged by corrosion with the perforation or brine, it is preferable in terms of worker safety and efficiency than using a discharge device. In the case of using a discharger, it may take some time until complete discharge because some residual voltage remains, but when discharging by erosion with the perforation or salt water, it is possible to shorten the time of the operation, thereby providing an efficient operation.

The degree of completion of the discharge can be confirmed through a decrease in voltage over time.

Most of the electrolyte contained in the lithium secondary battery may be removed through the discharge step.

Shredding stage

The pre-treatment method for a lithium secondary battery regeneration process according to the present invention includes crushing the discharged lithium secondary battery.

The crushing may be made by a crushing machine, but is not limited thereto.

The crushed material may be obtained through the crushing step.

The crushed material obtained through the crushing step may have a size of 0.1 cm to 7 cm, preferably 0.3 cm to 5 cm, and more preferably 0.5 cm to 3 cm. In this case, the secondary battery battery is crushed and decomposed to further decompose the positive electrode active material. It is advantageous because it has the advantage of allowing easy recovery.

In the present invention, the "size of crushed material" may mean the largest dimension value among the outer dimensions of the crushed particles.

The crushing may be primary crushing using a shredder cutter, and secondary crushing using a cut crusher/hammer crusher/roll crusher, but is not limited thereto.

The crushed material obtained through the second crushing step may have a size of 0.1 cm to 3 cm, preferably 0.3 cm to 2 cm, more preferably 0.5 cm to 1 cm, and in this case, a partially separated membrane and an anode in the crushed secondary battery battery / It is preferable because it has the advantage of easy separation of the cathode plate.

Crushing step

In the crushing step, the crushed crushed material undergoes a crushing step to remove most of the battery case, separator, electrode plate, and cathode/cathode material of the lithium secondary battery.

The grinding may be performed by milling, specifically, the milling may be mechanical milling. More specifically, one or more selected from the group consisting of roll-mill, ball-mill, jet-mill, planetary-mill and attrition-mill Can be made by Specifically, in the case of an electrode or an electrode assembly, it may be ground through mechanical milling described above.

When the target of the pulverization is an active material slurry, the contained solvent (NMP) is separated using a filter press or a centrifuge and the residual solvent is removed through a dryer, and then the agglomerated active material can be crushed by a mechanical mill. have.

When additionally crushing the active material in the crushed material obtained by crushing the electrode or the electrode assembly, an attrition mill may be used, and when wet grinding using the attrition mill, crushing efficiency may be increased. The time may be from 4.0 hours, preferably from 0.2 hours to 2.0 hours, more preferably from 0.3 hours to 1.0 hours, but is not limited thereto. However, when the milling is performed within the above range, it is preferable because the process time is shortened and the efficiency is excellent.

In another embodiment of the present invention, the pulverized product may have a size of 0.1 mm to 10 mm, preferably 0.1 mm to 7 mm, more preferably 0.1 mm to 5 mm, and in this case, recovery of the positive electrode active material in the classification step It is preferable because efficiency can be maximized.

The "size of the pulverized material" may mean the largest dimension value among the outer dimensions of the pulverized particles.

Firing stage

The pretreatment method for the regeneration process of the lithium secondary battery according to the present invention includes the step of firing the pulverized product, and the step of firing includes a first firing step, a second firing step and a third firing step.

The pulverized product that has been subjected to the pulverizing step may be subjected to the multi-stage sintering step as described above to remove the binder, separator, electrolyte, and negative electrode material, and separate the positive electrode current collector and the positive electrode active material.

In another embodiment of the invention, the first firing step is performed at a temperature of 100 °C to 200 °C, the second firing step is performed at a temperature of 500 °C to 750 °C, and the third firing step is It may be carried out at a temperature of 800 ℃ to 1,000 ℃.

In another embodiment of the present invention, the first firing step is performed for 0.1 hours to 10 hours, the second firing step is performed for 0.1 hours to 10 hours, and the third firing step is 0.1 hours to 10 hours. Can be performed for an hour.

The first firing step may be performed preferably 0.3 hours to 5 hours, more preferably 0.5 hours to 3 hours, a preferred temperature may be 120°C to 180°C, and a more preferred temperature may be 140°C to 160°C. .

The pulverized material is removed by a binder, a separator, an electrolyte, etc. by going through the first firing step.

The second firing step may be performed preferably 0.3 hours to 5 hours, more preferably 0.5 hours to 3 hours, and a preferred temperature may be 520°C to 680°C, and a more preferred temperature may be 550°C to 650°C. .

Hydrocarbon-based materials such as graphite and carbon black are removed from the pulverized product through the second firing step.

The third firing step may be performed preferably 0.3 hours to 5 hours, more preferably 0.5 hours to 3 hours, and a preferred temperature may be 820°C to 980°C, and a more preferred temperature may be 850°C to 950°C. .

Since the third firing temperature according to the present invention does not exceed 1000°C, the phenomenon of Li volatilization can be suppressed.

The positive electrode current collector and the positive electrode active material may be separated from the pulverized product through the third firing step.

It is preferable that the first firing step, the second firing step, and the third firing step sequentially pass the first firing step, the second firing step, and the third firing step of the temperature range in terms of energy efficiency. .

Since the firing step according to the present invention includes a first firing step, a second firing step, and a third firing step, rather than batch firing, impurities in the powder, such as the negative electrode current collector, the positive electrode current collector, the components of the case, etc. It is possible to suppress the phenomenon in which a large amount such as Cu, Al, Fe, etc., which can be included, can suppress the problem that remained without completely removing the binder, electrolyte, and the like.

In addition, there is an advantage that it is possible to shorten the process time and increase the efficiency of the finally obtained positive electrode active material powder by unifying the existing electrolytic solution, separator, cathode material, etc., without having to remove them individually through a multi-stage firing process.

The pretreatment method for the regeneration process of the lithium secondary battery according to the present invention does not use a solvent such as water or sulfuric acid when removing electrolytes, separators, current collectors, electrode composites, etc., and uses a multi-stage firing step to treat wastewater. Can also be suppressed.

Classification stage

In another embodiment of the present invention, the step of classifying the pulverized pulverized product; may further include a.

When the classification step is further included, the firing efficiency of the firing step is increased, and a phenomenon in which a large amount of gas is generated when removing the separation membrane can be suppressed, which is preferable.

Specifically, the classification step may be performed before the firing step, in which case the separation membrane, the case, the positive electrode/cathode current collector and the positive electrode active material are preferentially separated to reduce impurities that may occur in the multi-stage firing step. This is preferred.

More specifically, the classification separates the separator, the electrode plate, the negative electrode material, the electrode composite, the current collector and the positive electrode active material by a mechanical separation method using a mechanical separation method, such as air classification, or the separation of the sieve. can do.

If necessary, the classification may be performed continuously with the step of separating the crushed crushed material, in this case, for example, by using a mill continuously separating the crushed material from parts to be separated during the crushing process. It may be performed, but is not limited thereto.

In another embodiment of the present invention, the classifying step includes a first classifying step comprising an air specific gravity separation step; And a second classification step including a sieve separation step.

Specifically, the second classification step may be a step of separating the sieve. When sieving the pulverized material, the mesh of the sieve may be 50 to 500, preferably 100 to 400, and more preferably 200 to 300.

Separation membranes, cases, anode plates, and cathode plates hung on the top during classification may be re-separated if necessary. Most of the powder classified by sieving is a positive electrode active material, but a small amount of a positive electrode binder, a binder, a negative electrode active material, a positive electrode plate, and a negative electrode plate may be mixed.

Specifically, the classifying step may include a first classifying step of separating the separator, the case, the electrode plate and the electrode material, and a second classifying step of separating the case, the electrode plate, the current collector, and the separator, and the second classifying step. May be performed after the magnetic force selection step, which will be described later, but is not limited thereto.

When the classifying step includes the first classifying step and the second classifying step, it is preferable because there is an advantage in that the recovery efficiency of the positive electrode active material is increased.

Magnetic selection stage

In yet another embodiment of the present invention, the lithium secondary battery waste includes SUS, and a magnetic separation step of removing the SUS by magnetic separation (magnetic separation) of the classified debris; may further include a.

In another embodiment of the present invention, the magnet strength of the magnetic separation step may be 500 Gauss to 30,000 Gauss, preferably 1,000 Gauss to 20,000 Gauss, and more preferably 5,000 Gauss to 15,000 Gauss. When the magnet strength is within the above range, removal of SUS is effective and is preferable.

Magnetic sorting can remove the SUS in a continuous manner, but is not limited to this method. Specifically, in the present invention, the magnetic force selection step may be a continuous process.

Specifically, when the lithium secondary battery waste further includes stainless steel (SUS), the SUS can be removed by magnetic separation, but is not limited thereto.

The magnetic separation may remove the SUS by magnetically separating the primary classified pulverized material, or remove the SUS by magnetically separating after the secondary classification. Preferably, magnetic separation after the second classification is preferable because it reduces loss of the positive electrode active material and can effectively remove only steel (SUS).

The pre-treatment method for a lithium secondary battery regeneration process according to the present invention has an advantage of efficiently obtaining a positive electrode active material powder by using only a multi-stage firing process instead of a conventional complicated process. In addition, it is possible to perform a continuous process rather than a batch type, and has an advantage of suppressing powder loss occurring between batches, and since no harmful solvent such as sulfuric acid is used, it is possible to suppress a problem caused by wastewater treatment.

Hereinafter, examples will be described in detail to specifically describe the present specification. However, the embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more fully describe the present specification to those skilled in the art.

The pretreatment method for the lithium secondary battery regeneration process according to the present invention is performed, wherein the profile of the multi-stage firing according to the first firing step, the second firing step and the third firing step is shown in FIG. It is shown in Table 1 below by comparing the comparative examples according to the existing process.

Meanwhile, FIG. 3 is a post-classification image (left: classified separator, case, electrode plate, right: positive electrode active material) during the pretreatment process, and FIG. 4 is a positive electrode active material image after multi-stage firing is completed.

Comparative example
(Existing process) Example
(Multistage plasticity) time More than 24 hours 12 hours or less fair 3 or more such as electrolyte/separator/peeling process
Cathode materials are not separated Electrolyte/Separator 150℃
Cathode material: 700℃
Peeling: 900℃ Process number More than 3 processes 1 process Metal remaining after leaching Cu: 11.2 mg/L
Al: 734 mg/L
Fe: 22.9 mg/L Cu: 16.3 mg/L
Al: 521 mg/L
Fe: <0.1 mg/L

As can be seen by looking at Table 1, the pretreatment method for the lithium secondary battery regeneration process according to the present invention can shorten the existing process time corresponding to the multi-stage firing process, and three or more processes such as electrolyte/separation membrane/peeling process. Can be reduced in one step of multi-stage firing, and it can be seen that the productivity and efficiency are excellent.

In addition, the calcined waste cathode active material powder is 2M H ₂ SO ₄ , 5vol% H ₂ O ₂ When dissolved in the solution and leached through ICP analysis, when comparing the remaining metals (Cu, Al, Fe) other than Ni, Co, Mn, it can be seen that it exhibits an effect equal to or greater than that of the existing process.

Claims (11)

Discharging the lithium secondary battery waste;
Crushing the discharged lithium secondary battery waste;
Crushing the crushed crushed material; And
Calcining the pulverized material;
Including,
The firing step includes a first firing step, a second firing step and a third firing step,
Pre-treatment method for lithium secondary battery recycling process. According to claim 1,
The first firing step is carried out at a temperature of 100 ℃ to 200 ℃,
The second firing step is carried out at a temperature of 500 ℃ to 750 ℃,
The third firing step is carried out at a temperature of 800 ℃ to 1,000 ℃,
Pre-treatment method for lithium secondary battery recycling process. According to claim 2,
The first firing step is performed for 0.1 to 10 hours,
The second firing step is performed for 0.1 to 10 hours,
The third firing step is performed for 0.1 to 10 hours,
Pre-treatment method for lithium secondary battery recycling process. According to claim 1,
Classifying the pulverized pulverized material; a pretreatment method for a lithium secondary battery recycling process further comprising a. According to claim 1,
The pulverized product is a pre-treatment method for a lithium secondary battery regeneration process that is crushed to a size of 0.1 mm to 10 mm. According to claim 1,
The lithium secondary battery waste is a pretreatment method for a lithium secondary battery regeneration process comprising at least one selected from the group consisting of an electrolyte, a separator, an electrode composite, and a current collector. According to claim 1,
The lithium secondary battery waste is a pre-treatment method for a lithium secondary battery recycling process that includes at least one of the process scrap (scrap) generated in the production process of the waste lithium secondary battery and lithium secondary battery. According to claim 1,
The discharge perforates the lithium secondary battery; or,
A pretreatment method for a lithium secondary battery regeneration process that is corroded with a discharge solution containing brine (NaCl) or distilled water. According to claim 4,
The classifying step includes a first classifying step including an air specific gravity separation step; And a second classification step including a sieve separation step. According to claim 1,
The lithium secondary battery waste contains SUS,
A pre-treatment method for a lithium secondary battery regeneration process further comprising; a magnetic separation step of removing the SUS by magnetic separation of the classified crushed material. The method of claim 10,
The magnet strength of the magnetic separation step is 500 to 30,000 Gauss, the pre-treatment method for the lithium secondary battery regeneration process.

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