JP6918522B2 - Lithium-ion battery scrap disposal method - Google Patents

Description

The present invention relates to, for example, a method of heating and processing lithium ion battery scrap prior to acid leaching when recovering valuable metal from lithium ion battery scrap, and in particular, increasing processing time and cost. It proposes a technology that can improve the recovery rate of valuable metals while suppressing it.

Lithium ion batteries used in many industrial fields including various electronic devices use a lithium metal salt containing manganese, nickel and cobalt as a positive electrode active material, and a positive electrode material and a negative electrode material containing the positive electrode active material. It is wrapped in a housing containing aluminum, and in recent years, with the increase in the amount used and the range of use, the amount discarded due to the product life of the battery and defects in the manufacturing process has increased. Is in a situation.
Under such circumstances, it is desired to easily recover the above-mentioned valuable metals such as nickel and cobalt from the lithium-ion battery scrap that is discarded in large quantities at a relatively low cost for reuse.

To process lithium-ion battery scrap for the recovery of valuable metals, first, by heating and roasting the lithium-ion battery scrap, harmful electrolytes (flammable liquid, etc.) contained inside are removed. In addition to detoxifying, crushing and sieving are performed in this order to carry out a pre-step of removing aluminum contained in the housing and the positive electrode base material to some extent.
Next, the powdered positive electrode material obtained in the previous step is acid-leached, and lithium, nickel, cobalt, manganese, aluminum and the like that can be contained therein are dissolved in the solution to obtain a liquid after leaching.

After that, a recovery step is performed to separate each metal element dissolved in the liquid after leaching. Here, in order to separate each metal leached into the leached solution, the leached solution is sequentially subjected to multiple steps of solvent extraction or neutralization according to the metal to be separated, and further, each step. The respective solutions obtained in the above are subjected to back extraction, electrolysis, carbonation and other treatments. Specifically, each valuable metal can be recovered by first recovering aluminum, then manganese, then cobalt, then nickel, and finally leaving lithium in the aqueous phase.

By the way, in recent years, a so-called lithium ion polymer battery, which uses a polymer as an electrolyte for flowing lithium ions between the positive electrode and the negative electrode of a lithium ion battery, has been put into practical use because of its low risk of ignition during use. It has come to be done.

However, when such a lithium ion polymer battery is discarded after use or the like and an attempt is made to recover a valuable metal from the battery, the electrolyte containing the polymer is flame-retardant during the heating in the above-mentioned previous step. As a result, the combustion temperature does not rise easily, and combustion becomes insufficient. As a result, the valuable metal such as cobalt is not easily peeled off from the aluminum foil even after heating, and the state in which the valuable metal is in close contact with the aluminum foil is maintained, so that the distribution rate of cobalt or the like is lowered in the sieving step.
On the other hand, in order to easily peel off the valuable metal from the aluminum foil, it is necessary to heat the lithium ion polymer battery whose combustion temperature does not easily rise for a long period of time, which causes a problem that the processing time and cost increase.

An object of the present invention is to solve such a problem, and an object of the present invention is to increase processing time and cost in heating and processing a polymer-free electrolyte battery such as a lithium ion polymer battery. It is an object of the present invention to provide a method for treating lithium ion battery scrap, which can contribute to the improvement of the recovery rate of valuable metals while suppressing the above.

The inventor has stated that since the electrolyte component of the conventional lithium-ion battery having a polymer-free electrolyte is flammable, the temperature rise rate is high during heating, the temperature rises rapidly, and the combustion temperature rises further. Focusing on the ease of use, by heating a polymer-containing electrolyte battery having a polymer-containing electrolyte such as the above-mentioned lithium ion polymer battery together with a polymer-free electrolyte battery having such a polymer-free electrolyte, the polymer-containing electrolyte battery is heated. We thought that the electrolyte battery could be sufficiently burned.

When the polymer-free electrolyte battery is heated by itself, the combustion temperature becomes too high, so that the aluminum foil is easily embrittled and powdered, and the aluminum foil is easily crushed during the subsequent crushing. At this time, it becomes difficult to remove the aluminum foil by leaving it on the sieve. If a large amount of aluminum is mixed in the positive electrode material obtained under the sieve in this way, a treatment for separating / removing aluminum is required in the recovery step, which causes a problem that the cost increases.
On the other hand, as described above, by heating the polymer-free electrolyte battery together with the polymer-containing electrolyte battery, the flame-retardant electrolyte of the polymer-containing electrolyte battery suppresses an increase in the combustion temperature of the polymer-free electrolyte battery. As a result, it is considered that the rate of temperature rise and the maximum temperature reached can be controlled within an appropriate range, and both batteries can be effectively heat-treated.

Based on the above findings, the method for treating the lithium ion battery scrap of the present invention is a method for treating the lithium ion battery scrap by heating, and the lithium ion battery scrap is a polymer-containing electrolyte battery having an electrolyte containing a polymer. , And a polymer-free electrolyte battery having a polymer-free electrolyte, and the ratio of the polymer-free electrolyte battery in the lithium ion battery scrap is set to 20% or more and 70% or less by weight, and the polymer is contained. The present invention is to heat the electrolyte battery together with the polymer-free electrolyte battery , and at the time of heating, the polymer-containing electrolyte battery and the polymer-free electrolyte battery are alternately stacked and arranged in contact with each other .

Here, in particular, the ratio of the polymer-free electrolyte battery in the lithium ion battery scrap is preferably 20% or more, more preferably 30% or more in terms of mass ratio.

Further, preferably, by arranging the polymer-containing electrolyte battery and the polymer-free electrolyte battery in the heating container at the time of heating, the flame directly hits the housings of the polymer-containing electrolyte battery and the polymer-free electrolyte battery. Heat the polymer-containing electrolyte battery and the polymer-free electrolyte battery while preventing them.

Further, at the time of heating is such that the 50 ° C. / sec or more Noborihan circumference on the temperature of the polymer-containing electrolyte battery and a polymer-free electrolyte batteries at a heating rate of 300 ° C. or less, in particular 200 ° C. or less, the polymer containing It is preferable to heat the electrolyte battery and the polymer-free electrolyte battery.
A stationary furnace can be used for the heat treatment of the lithium ion battery scrap.

According to the present invention, by heating the polymer-containing electrolyte battery together with the polymer-free electrolyte battery, the heating rate and the maximum temperature can be controlled in an appropriate range by utilizing the magnitude of their combustion temperatures.
As a result, it is possible to shorten the processing time and reduce the cost while improving the recovery rate of the valuable metal as compared with the case where the polymer-containing electrolyte battery is heated alone.

It is a graph which shows the sample temperature and the temperature in a furnace of Example 1. FIG. It is a graph which shows the aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery and the polymer-free electrolyte battery of Example 1. It is a graph which shows the sample temperature and the temperature in a furnace of Example 2. It is a graph which shows the aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery and the polymer-free electrolyte battery of Example 2. It is a graph which shows the sample temperature and the temperature in a furnace of Example 3. It is a graph which shows the aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery and the polymer-free electrolyte battery of Example 3. It is a graph which shows the sample temperature and the temperature in a furnace of Comparative Example 1. It is a graph which shows the aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery and the polymer-free electrolyte battery of Comparative Example 1.

Hereinafter, embodiments of the present invention will be described in detail.
The method for treating a lithium ion battery scrap according to an embodiment of the present invention is a method for treating the lithium ion battery scrap by heating, and the lithium ion battery scrap is a polymer-containing electrolyte battery having an electrolyte containing a polymer. And, a polymer-free electrolyte battery having a polymer-free electrolyte is included, and the polymer-containing electrolyte battery and the polymer-free electrolyte battery are mixed and heated.

(Lithium-ion battery)
The lithium-ion battery scrap targeted by the present invention is a waste of a lithium-ion battery that can be used in various electronic devices such as mobile phones. More specifically, it is discarded due to the life of the battery product, manufacturing failure, or other reasons, and by targeting such lithium-ion battery scrap, it is possible to effectively utilize resources.
In the embodiment of the present invention, specifically, as the lithium ion battery scrap, a polymer-containing electrolyte battery having a polymer-containing electrolyte and a polymer-free electrolyte battery having a polymer-free electrolyte are used. Lithium-ion batteries of other types may be further used.

The "electrolyte" as used in the present invention means a substance having electrical conductivity and allowing ions such as lithium ions to be exchanged between the positive electrode and the negative electrode, and the form thereof such as liquid, solid, and gel is used. It doesn't matter.
The electrolyte of a polymer-free electrolyte battery is generally a solution of a lithium salt dissolved in an organic solvent. Examples of the lithium salt include LiPF ₆ , LiBF ₄ , LiClO ₄ , Li [PF ₃ (C ₂ CF ₅ ) ₃ ] and the like, and examples of the organic solvent include propylene carbonate (PC) and ethylene. Examples thereof include carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), and lithium carbonate (EMC).

The electrolyte of the polymer-containing electrolyte battery is usually a gel obtained by impregnating the above solution with a polymer such as polyethylene oxide (PEO), polypropylene oxide (PPO), polyvinylidene fluoride (PVdF), or polyacrylic nitrile (PAN). There are those in which the solution itself is polymerized, those in which the polymer itself is made conductive, and the like, and such a polymer-containing electrolyte battery is sometimes referred to as a lithium ion polymer battery. If at least a part of the electrolyte contains a polymer, the effect of controlling the combustion temperature by mixing and heating with the polymer-free electrolyte battery can be obtained.

The polymer-free electrolyte battery is generally a laminated type battery in which the periphery is wrapped in a housing containing aluminum, but the present invention is not limited to this, and a can type or the like may be used.
Examples of the housing of the polymer-free electrolyte battery include those made of only aluminum and those containing aluminum, iron, aluminum laminate, and the like.
Recently, polymer-containing electrolyte batteries using laminating technology have also been manufactured. Therefore, the polymer-containing electrolyte batteries are also wrapped in a housing containing aluminum in the same manner as the polymer-free electrolyte batteries. Generally, it is a laminated type, but it is not limited to this, and a can type or the like may be used.

In either of the above-mentioned polymer-free electrolyte battery and polymer-containing electrolyte battery, as in the case of a general lithium ion battery, a single metal oxide of lithium, nickel, cobalt and manganese, or a single metal oxide of lithium, nickel, cobalt and manganese is contained inside. It can include a positive electrode active material composed of two or more kinds of composite metal oxides and the like, and an aluminum foil (positive electrode base material) to which the positive electrode active material is applied and fixed by an organic binder or the like. In addition, the polymer-free electrolyte battery and the polymer-containing electrolyte battery may contain copper, iron and the like.

The polymer-free electrolyte battery and the polymer-containing electrolyte battery have an electrode structure of, for example, a wound type or a laminated type, and the overall form includes a cylindrical type, a square type, and the like. In the case of a square shape, it can have a substantially square or rectangular planar contour shape, and in this case, the dimensions before heat treatment are, for example, 40 mm to 80 mm in length, 35 mm to 65 mm in width, and thickness. Can be targeted for 4 mm to 5 mm, but is not limited to those having this size.

(Heating process)
In the heating step, the polymer-free electrolyte battery and the polymer-containing electrolyte battery described above are mixed and heated.

When only the polymer-free electrolyte battery is burned, the temperature rise rate becomes high due to the flammability of the electrolyte component, the temperature rises sharply, and the combustion temperature tends to rise further. Especially here, the maximum temperature may be transcended due to a spike-like rapid temperature rise. As a result, the housing containing aluminum and the aluminum foil become brittle and pulverized, and these are easily crushed in the pulverization step described later, and it becomes difficult to remove the aluminum by leaving it on the sieve in the sieving step described later.
On the other hand, when only the polymer-containing electrolyte battery is burned, the combustion temperature is difficult to rise due to the flame retardancy of the electrolyte, and the combustion becomes insufficient. In this case, the valuable metal such as cobalt is not sufficiently peeled off from the aluminum foil, and the distribution rate of cobalt or the like in the recovery step described later is lowered.

On the other hand, as in the embodiment of the present invention, by mixing and heating the polymer-free electrolyte battery and the polymer-containing electrolyte battery, the heating rate and the maximum temperature can be controlled in an appropriate range. The brittleness and powdering of the aluminum foil of the polymer-free electrolyte battery are suppressed, and the non-combustibility of the polymer-containing electrolyte battery is prevented. As a result, aluminum can be effectively removed in the sieving step, and cobalt and the like can be effectively peeled from the aluminum foil.

From the viewpoint of effectively shortening the processing time as compared with the case where the polymer-free electrolyte battery is heat-treated alone, the ratio or ratio of the polymer-free electrolyte battery contained in the lithium ion battery scrap is a weight ratio. It is preferably 20% or more, and more preferably 30% or more.
On the other hand, if the ratio of the polymer-free electrolyte battery is too large, the combustion temperature rises sharply, and due to miniaturization due to embrittlement of aluminum, removal of aluminum may become a problem in the subsequent recovery of valuable metals. I am concerned. Therefore, the ratio or ratio of the polymer-free electrolyte battery in the lithium ion battery scrap is preferably 70% or less in terms of weight ratio.

More specifically, in order to more appropriately control the heating rate and the maximum temperature, the mixing ratio of the polymer-containing electrolyte battery and the polymer-free electrolyte battery is preferably 50:50 to 78:22. In particular, it is even more preferable to set the temperature from 60:40 to 78:22. If the proportion of the polymer-free electrolyte battery is too large, the amount of the electrolyte is also large, and there is a concern that the rapid temperature rise cannot be sufficiently suppressed. On the other hand, if the proportion of the polymer-containing electrolyte battery is too large, combustion may not be sufficiently performed due to the presence of a large amount of the electrolyte containing a flame-retardant polymer.

When the polymer-free electrolyte battery and the polymer-containing electrolyte battery are mixed and heated, it is preferable that the polymer-free electrolyte battery and the polymer-containing electrolyte battery are alternately stacked and arranged in contact with each other. .. By stacking and arranging them alternately in this way, it becomes easy for heat to be released to the polymer-containing electrolyte battery.

Further, here, it is advantageous to use an ordinary incinerator that incinerates the object to be incinerated by a flame, for example, a stationary incinerator, in that an increase in equipment cost can be suppressed as compared with the case where special equipment is used. ..
However, in such an incinerator, a flame is directly applied to the housing of the polymer-free electrolyte battery and the polymer-containing electrolyte battery having the housing as described above, and the polymer-free electrolyte battery and the polymer-containing electrolyte battery are directly applied. When heated, the housing, aluminum foil, and copper foil are oxidized and brittle. In this case, when the polymer-free electrolyte battery and the polymer-containing electrolyte battery are crushed after the heating step, the embrittled housing and foil are also easily crushed into small pieces. A large amount of aluminum contained in the housing and the like is mixed. This increases the work and cost of recovering the aluminum later.

To deal with this, in this embodiment, the polymer-free electrolyte battery and the polymer-containing electrolyte battery are placed in a heating container in order to prevent the flame from directly hitting the polymer-free electrolyte battery and the polymer-containing electrolyte battery. Then, the heating container is put into the incinerator to heat the polymer-free electrolyte battery and the polymer-containing electrolyte battery.
Thereby, the heating container can prevent the housing of the polymer-free electrolyte battery and the polymer-containing electrolyte battery arranged therein from being exposed to the flame, so that the polymer-free electrolyte battery and the polymer-containing electrolyte battery can be prevented from being exposed to flames. Oxidation of the housing and foil is prevented, and the polymer-free electrolyte battery and the polymer-containing electrolyte battery can be effectively roasted. As a result, until the end of the heating process, the housing maintains the surroundings of the polymer-free electrolyte battery and the polymer-containing electrolyte battery, so that the housing and foil can be thinned during crushing and sieving. Granulation can be prevented and these can be easily and reliably removed on the sieve.

As the heating container, various materials and shapes can be used as long as it can withstand the high temperature in the incinerator. The heating container may be made of, for example, steel or other iron, and may have heat resistance to the temperature inside the incinerator in the heat treatment of the lithium ion battery.
A gas is generated from a polymer-free electrolyte battery or the like due to vaporization of a liquid electrolyte due to heating, but if this gas cannot be discharged to the outside from the heating container, an explosion due to the gas will occur. There is a risk. Therefore, it is desirable that the heating container is not sealed. The heating container may be provided with a gap for venting gas.

Further, in this heating step, the lithium ion battery is set so that the temperature rise rate of the polymer-free electrolyte battery and the polymer-containing electrolyte battery during heating is 300 ° C. or lower as a temperature range in which the temperature rises sharply with respect to the tendency of temperature rise by the burner. It is preferable to heat. That is, when this temperature exceeds 300 ° C., the sample temperature may be higher than the melting point of Al. Therefore, more preferably, this temperature is set to 200 ° C. or lower.
On the other hand, if the heating rate is too slow, the heat treatment time becomes long, which may become a bottleneck during the actual treatment. Therefore, the above temperature range can be, for example, 200 ° C. or higher, preferably 250 ° C. or higher.
Here, the “rapid rise” can be a temperature rise rate of 50 ° C./sec or more.

(Leaching process and recovery process)
After the above heating step, by crushing and sieving as necessary, a sieving product containing a positive electrode material such as granular or powdery material from which aluminum is sufficiently removed can be obtained.
Then, a sieve containing the granular or powdery positive electrode material is added to an acidic solution such as sulfuric acid and leached from the leached liquid, and nickel, cobalt, manganese, etc. dissolved in the leached liquid are used. To collect. Specifically, for example, manganese is first separated and recovered by solvent extraction or neutralization, then cobalt is then sequentially separated and recovered, and finally lithium is left in the aqueous phase.

Here, by mixing and heating the polymer-free electrolyte battery and the polymer-containing electrolyte battery in the heating step described above, the rate of temperature rise and the maximum temperature can be controlled within an appropriate range, and as a result, the liquid after leaching is prepared. Since the molten metal contains almost no aluminum, the process required for separating and removing the aluminum in the recovery step can be simplified or omitted. As a result, it is possible to improve the processing efficiency and reduce the processing cost.
Further, since cobalt and the like are sufficiently peeled from the aluminum foil by the above-mentioned heating step and crushing and sieving, the distribution rate of cobalt and the like in the recovery step can be greatly increased.

Next, the method for treating the lithium ion battery of the present invention was carried out on a trial basis, and its effect was confirmed, which will be described below. However, the description here is for the purpose of mere illustration, and is not intended to be limited thereto.
A test in which samples having different mixing ratios of a polymer-free electrolyte battery and a polymer-containing electrolyte battery are prepared as in Examples 1 to 3 and Comparative Example 1 below, and these are heated, crushed, and then sieved. The aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt partition ratio were determined respectively.

(Example 1)
As samples, 101.5 g of a polymer-containing electrolyte battery and 128.4 g of a polymer-free electrolyte battery were prepared. The mixing ratio of the polymer-containing electrolyte battery and the polymer-free electrolyte battery is 44:56. These were mixed and heated in an incinerator. The sample temperature and the temperature inside the furnace at that time are shown in FIG. After that, when sieving was performed and the sieving was confirmed, the grades of each metal under the sieving of the polymer-containing electrolyte battery and the polymer-free electrolyte battery were shown in Tables 1 and 2 according to the sieving size. It was as shown.
The aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery (polymer) and the polymer-free electrolyte battery (laminate) are shown in FIG.

(Example 2)
As a sample, 126.4 g of a polymer-containing electrolyte battery and 85.6 of a polymer-free electrolyte battery were prepared. The mixing ratio of the polymer-containing electrolyte battery and the polymer-free electrolyte battery is 60:40. These were mixed and heated in an incinerator. The sample temperature and the temperature inside the furnace at that time are shown in FIG. After that, when sieving was performed and the sieving was confirmed, the grades of each metal under the sieving of the polymer-containing electrolyte battery and the polymer-free electrolyte battery were shown in Tables 3 and 4, respectively, according to the sieving size. It was as shown.
The aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery (polymer) and the polymer-free electrolyte battery (laminate) are shown in FIG.

(Example 3)
As samples, 150.0 g of a polymer-containing electrolyte battery and 42.5 g of a polymer-free electrolyte battery were prepared. The mixing ratio of the polymer-containing electrolyte battery and the polymer-free electrolyte battery is 78:22. These were mixed and heated in an incinerator. The sample temperature and the temperature inside the furnace at that time are shown in FIG. After that, when sieving was performed and the sieving was confirmed, the grades of each metal under the sieving of the polymer-containing electrolyte battery and the polymer-free electrolyte battery were shown in Tables 5 and 6, respectively, according to the sieving size. It was as shown.
The aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio of each of the polymer-containing electrolyte battery (polymer) and the polymer-free electrolyte battery (laminate) are shown in FIG.

(Comparative Example 1)
As a sample, only a polymer-containing electrolyte battery was prepared. The mixing ratio of the polymer-containing electrolyte battery and the polymer-free electrolyte battery is 100: 0. This was heated in an incinerator. The sample temperature and the temperature inside the furnace at that time are shown in FIG. After that, when sieving was performed and the under-sieving was confirmed, the grade of each metal under the sieving was as shown in Table 7 according to the sieving size.
The aluminum grade under the sieve, the ratio of lithium to aluminum, and the cobalt distribution ratio are shown in FIG.

From the above results, when only the polymer-containing electrolyte battery was heated in Comparative Example 1, as shown in FIG. 7, the sample temperature rose slowly with respect to the temperature inside the furnace, which required a lot of processing time. When the polymer-containing electrolyte battery and the polymer-free electrolyte battery were mixed and heated in Examples 1 to 3, the sample temperature rapidly increased and the processing time could be shortened, as shown in FIGS. I understand. Further, it is clear that this tendency becomes more remarkable as the proportion of the polymer-free electrolyte battery increases.
Therefore, according to the present invention, it has been found that an increase in processing time and cost can be effectively suppressed.

Claims (6)

A method of heating and processing lithium-ion battery scrap.
The lithium ion battery scrap comprises a polymer-containing electrolyte battery having a polymer-containing electrolyte and a polymer-free electrolyte battery having a polymer-free electrolyte.
The ratio of the polymer-free electrolyte battery in the lithium ion battery scrap is set to 20% or more and 70% or less by weight, and the polymer-containing electrolyte battery is heated together with the polymer-free electrolyte battery.
A method for treating lithium ion battery scrap, in which the polymer-containing electrolyte battery and the polymer-free electrolyte battery are alternately stacked and arranged in contact with each other during heating. The method for treating lithium ion battery scrap according to claim 1, wherein the ratio of the polymer-free electrolyte battery in the lithium ion battery scrap is 30% or more by weight. By arranging the polymer-containing electrolyte battery and the polymer-free electrolyte battery in the heating container during heating, the polymer can be prevented from directly hitting the housing of the polymer-containing electrolyte battery and the polymer-free electrolyte battery. The method for treating lithium ion battery scrap according to claim 1 or 2, wherein the containing electrolyte battery and the polymer-free electrolyte battery are heated. The polymer-containing electrolyte battery and the polymer-free electrolyte battery are heated so that the temperature rise range of the polymer-containing electrolyte battery and the polymer-free electrolyte battery at a temperature rise rate of 50 ° C./sec or more is 300 ° C. or lower. The method for treating lithium ion battery scrap according to any one of claims 1 to 3. As Noborihan circumference on the temperature of the polymer-containing electrolyte battery and a polymer-free electrolyte batteries at 50 ° C. / sec or more Atsushi Nobori rate is 200 ° C. or less, heating the polymer-containing electrolyte battery and a polymer-free electrolyte batteries The method for treating lithium ion battery scrap according to any one of claims 1 to 4. The method for treating lithium-ion battery scrap according to any one of claims 1 to 5, wherein a stationary furnace is used for heat treatment of the lithium-ion battery scrap.

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