JP2015195129A - Treatment method for used lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method which exerts excellent treatment effect on a used lithium ion battery, is excellent in economical efficiency, produces only a small amount of environmental load and is easy to implement.SOLUTION: A treatment method for a lithium ion battery comprises: crushing a mixture of positive electrode material and negative electrode material of a used lithium ion battery into pieces of a few millimeters or less to peel off active material from a collector of the electrode material; sieving the crushed mixture to separate the same into middle grains formed mainly of the crushed collector material and fine grains formed mainly of the crushed active material; and collecting the fine grains and meanwhile, performing gravity sorting for the medium grains and separating the same into light weight grains formed mainly of aluminum and heavy weight grains formed mainly of copper. In the method, for example, a roughly crushed mixture of the mixture of the positive electrode material and the negative electrode material is further processed through secondary crushing to sieve the mixture into coarse grains of 5 mm or more, middle grains of 5 mm or less and 0.5 mm or more, and fine grains of less than 0.5 mm.

Description

The present invention relates to a method for sorting and recovering electrode materials used in lithium ion batteries, and more specifically, according to the material, the positive and negative electrode current collectors of lithium ion batteries and the active material applied to the current collectors. It is related with the processing method which sorts and collects effectively.

The electrode current collector of a secondary battery such as a lithium ion battery is made of aluminum or copper, and an active material made of a compound such as cobalt, nickel, manganese, lithium, or a carbon compound such as graphite is coated thereon. Has been. The metal components used as these current collectors and active materials are of high quality, and it is desirable to recover each of these metal components when processing used batteries.

Conventionally, the following methods are known as processing methods for lithium ion batteries.
(B) After the positive electrode material collected from the used battery is cut and heated to volatilize the binder, the active material is separated by impact crushing and separated into a current collector and an active material by a vibrating sieve (patent) No. 5269228).
(B) The used battery is heat-treated to remove organic matter, and then the exterior body is cut and removed. The positive electrode material and the negative electrode material are visually selected by hand, and the positive and negative electrodes are crushed and collected by a vibrating sieve. Sorting into electric material and active material (Japanese Patent Laid-Open No. 2013-80595).
(C) The used battery is crushed and washed to remove the organic solvent and electrolyte, and then separated into the positive electrode material and other parts, and the active material is peeled off by adding alkali to the positive electrode material and the current collector. A mixed slurry is obtained, and the residue is collected and sieved to separate into a current collector and an active material (Japanese Patent Laid-Open No. 2012-126945).
(2) Pre-roasting used batteries to remove organic substances and then crushing them to screen mainly into current collector lump and active material powder, and then oxidative roasting the powder After that, reduction roasting is performed to make Co or Ni into metal, iron or manganese oxide to make a slurry, and the residue is magnetically separated to separate and recover the magnetic deposit (Co, Ni) (Japanese Patent Laid-Open No. 2012-229481).

Japanese Patent No. 5269228 JP 2013-80595 A JP 2012-126945 A JP 2012-229481 A

Many of the conventional processing methods described above are performed mainly on the positive electrode material, and even when the entire battery is processed, after the negative electrode is separated, the positive electrode material is mainly processed. Even when the positive electrode material and the negative electrode material are processed at the same time, the active material contains a rare metal such as cobalt. Therefore, the active material separated from the current collector is recovered by various processing methods. The treatment process of the remaining current collector mixture is not very detailed. In particular, since the current collector is in the form of a sheet, direct physical sorting is difficult, and an effective treatment method is required. In addition, when the current collector and the active material are processed mainly in a wet state, burdens such as a solid-liquid separation operation and a wastewater treatment operation occur. Furthermore, the environmental load caused by the exhaust gas becomes a problem in the method of removing the organic matter by baking the pulverized battery. Further, the processing method for performing manual selection by visual inspection is heavy.

The present invention solves the above-mentioned problems in conventional processing methods, and provides a processing method that is excellent in processing effect, excellent in economic efficiency, small in environmental load, and easy to implement.

[1] A mixture of a positive electrode material and a negative electrode material of a used lithium ion battery is crushed to a few mm or less, the active material is peeled from the current collector of the electrode material, and the crushed mixture is sieved to obtain a current collector. The crushed material is mainly divided into medium-sized material and the active material crushed material is mainly divided into fine particles, and the fine particles are collected. A method for treating a used lithium ion battery, characterized in that it is separated and collected into heavy objects.
[2] The coarsely crushed mixture obtained by roughly crushing the mixture of the positive electrode material and the negative electrode material is further subjected to secondary crushing to obtain coarse particles having a particle size of more than 5 mm, medium particles of 5 mm or less to 0.5 mm or more, 0 The method for treating a used lithium ion battery according to the above [1], wherein sieving into fine particles of less than 5 mm is performed.
[3] Medium particles are either (a) screened for specific gravity as is, or (b) classified into specific gravity by classification to 2 mm or less to 0.5 mm or more, or (c) 1 mm or less to 0.5 mm or more. The method for treating a used lithium ion battery according to the above [1] or [2], wherein the specific gravity is classified and classified.
[4] Roughly crushing a mixture of a positive electrode material and a negative electrode material of a used lithium ion battery, or detoxifying the mixture and then crushing the mixture, and further removing the resin by water tank or wind sorting, The remaining coarsely crushed mixture is further subjected to secondary crushing, and sieved to coarse particles having a particle size of more than 5 mm, medium particles of 5 mm or less to 0.5 mm or more, and fine particles of less than 0.5 mm. [1] A method for treating a used lithium ion battery according to any one of [3] above.
[5] The used lithium ion according to any one of [1] to [4] above, wherein the coarsely crushed mixture is subjected to magnetic separation and the secondary pulverization is performed after the coarsely crushed mixture is removed. Battery processing method.
[6] The method for treating a used lithium ion battery according to any one of the above [1] to [5], wherein the combustible material contained in the battery is sieved into coarse particles.
[7] The above-mentioned [1] to [6], wherein the recovered fine particles are reused as raw materials of cobalt, nickel, manganese, and lithium, the recovered lightweight materials are used as aluminum materials, and the recovered heavy materials are reused as copper materials. ] The processing method of the used lithium ion battery described in any of the above.

[Specific description]
In the treatment method of the present invention, a mixture of a positive electrode material and a negative electrode material of a used lithium ion battery is crushed to a few mm or less to separate the active material from the current collector of the electrode material, and the crushed mixture is sieved. In addition, the current collector crushed material is mainly divided into medium-sized material and the active material crushed material is mainly divided into fine-grained material, and the fine-grained material is recovered, while the medium-grained material is subjected to specific gravity sorting to make the lightweight material mainly composed of aluminum. And a processing method for a used lithium ion battery that is separated into a heavy weight mainly composed of copper and collected.
An example of the processing method of the present invention is shown in FIG.

The treatment method of the present invention crushes a mixture of a positive electrode material and a negative electrode material of a used lithium ion battery. The mixture of the positive electrode material and the negative electrode material is a mixture of only the positive electrode material and the negative electrode material by separating and removing plastics (resins) such as a separator and an outer package, or a state in which a separator or an outer package is contained. Any of these may be used. Plastics can be removed by water tank or wind sorting after rough crushing (primary crushing).

As the used lithium ion battery which is a treatment target of the present invention, a non-detoxified battery can be used, but a detoxified battery is preferable. Detoxification treatment and rough crushing may be performed as follows, for example.
(A) The internal electrolyte solution is washed away to make it harmless and then roughly crushed. (B) The internal electrolyte is washed away and rendered harmless, and then dried and roughly crushed. (C) After roughly crushing the battery, the internal electrolyte solution is washed away and detoxified. (D) After roughly crushing the battery, the internal electrolyte is washed away, detoxified, and dried. (E) The battery is treated at a high temperature to vaporize or decompose the electrolyte to render it harmless, and then roughly crushed. (F) After roughly crushing the battery, the electrolyte solution is vaporized or decomposed to be detoxified. In the processes (a) to (f), a battery having a residual voltage of 2 V or more may be subjected to a discharge process in advance.

In the case of washing, the main solvent of the washing liquid is preferably an organic solvent or water. Further, when an organic cleaning solution is used, it is preferable to collect and use the organic components of the electrolyte contained in the lithium ion battery because the purchase cost of the cleaning solution and the waste liquid treatment are unnecessary. As the drying means, a ventilation type, hot air type, air current type, infrared type, drum type, vacuum dryer or the like can be used. The exhaust gas at this time may be post-combusted and released to the atmosphere, or the vaporized solvent can be recovered and reused.

When the washing treatment is not performed or when the washing is insufficient, the electrolyte lithium hexafluorophosphate (LiPF ₆ ) can be decomposed and rendered harmless by adding water to the battery. Water may be sprayed or applied directly to the battery crushed material, or water may be added by exposing the battery to a stream of water vapor or moisture. Note that hydrogen fluoride (HF) generated by decomposition of lithium hexafluorophosphate can be recovered by reacting with calcium carbonate to form calcium fluoride (CaF ₂ ).

Further, when an acid or alkali is added to the battery, the binding force between the current collector and the active material becomes weak, and the active material attached to the surface can be easily peeled off. However, if water, acid, or alkali is excessive, the current collector may become too brittle or denatured, making peeling difficult.

For rough crushing, for example, a used lithium ion battery is roughly crushed (primary crushing) into pieces of about 2 to 10 cm using a biaxial crusher or the like.

Crude crushed material from which resins and magnetic deposits have been removed by wind sorting or magnetic separation is further crushed to 2 cm or less, preferably 5 mm or less (secondary crushing) to obtain active materials from the positive electrode current collector and the negative electrode current collector, respectively. To peel off. As the crushing means, it is preferable to use a hammer mill or the like, or a means capable of effectively performing impact crushing, shear crushing, surface crushing or crushing for promoting the curling of the sheet-like current collector, such as a cutter mill, a mixer, or an attritor. In order to avoid excessive pulverization, a crusher may be provided with a screen or the like for discharging crushed material having a predetermined particle size or less out of the system.

In general, the current collector of the positive electrode is made of high-purity aluminum, and the current collector of the negative electrode is made of high-purity copper. Each current collector is a sheet or foil having a thickness of about 10 μm. Since these sheet or foil current collectors are malleable, they are not crushed finely, but become medium-sized crushed materials. On the other hand, since the active material adhering to the current collector is an aggregate of particles of about 1 to 50 μm, it is finely crushed into fine particles and peeled off from the current collector.

Specifically, when the coarsely crushed mixture obtained by roughly crushing (primary crushing) the mixture of the positive electrode material and the negative electrode material is secondary crushed to several millimeters or less, for example, 5 mm or less, the current collector is approximately 5 mm or less to 0.5 mm or more. Since it becomes a medium-sized crushed material and the active material is generally a fine-sized crushed material of less than 0.5 mm, these can be screened and selected. In addition, depending on the battery components, other combustible materials such as aluminum laminate and plastics that could not be removed are not crushed even in the secondary crushing stage. For example, it remains larger than 5 mm.

This secondary crushed material is sieved to separate the current collector crushed material into medium-sized material and active material crushed material as main material. Depending on the battery components, other combustible materials may be used. Separate into grains. For example, in the separation of fine particles and medium particles, sieving may be performed using a vibrating sieve having an aperture of 0.5 mm. By this sieving, for example, about 98 wt% of the positive electrode active material and 100 wt% of the negative electrode active material can be separated from the current collector and separated.

Other combustible materials such as plastics are hardly crushed even at the stage of secondary crushing, and remain in a coarse crushing particle size, for example, larger than 5 mm. It is good to screen using a vibration sieve having an appropriate opening.

Since the separated fine particles (particle size of less than 0.5 mm) are high-grade compounds such as cobalt, nickel, manganese, or lithium, they can be reused as recycling materials for the above metals.

On the other hand, the separated medium particles (particle size of 5 mm or less to 0.5 mm or more) are either (i) directly selected for specific gravity, or (b) classified to 2 mm or less to 0.5 mm or more (particle size adjustment) for specific gravity. Or (c) Classifying (grain size adjustment) to 1 mm or less to 0.5 mm or more to select specific gravity. In the case of classification, a vibrating sieve is preferably used. By this specific gravity sorting, it is possible to sort into lightweight and heavy items. If classification and specific gravity selection are performed as in [c] above, it is easy to separate into a light weight mainly made of aluminum and a heavy weight mainly made of copper. At this time, what remains with a particle size larger than 1 mm may be returned to the secondary crushing and crushed again.

In the specific gravity sorting, a wind sorting, a rocking table, or an air table may be used when dry sorting is performed. For example, in an air table, particles with a large specific gravity are transported on the table surface by vibration and friction without much influence of the air flow, but particles with a small specific gravity float from the table surface and slide down under the influence of the air flow. Therefore, it can be easily separated into a heavy object and a light object. Moreover, when performing wet sorting, jig sorting, thin flow sorting, multiple sorting, or the like can be used.

Since the selected lightweight material is a high-quality aluminum compound and the heavy material is a high-quality copper compound, these can be reused as a recycled raw material for aluminum and copper.

Since the treatment method of the present invention can reduce the input chemicals, input energy, waste water and waste gas, it has an advantage of relatively low environmental load. In addition, since there is no complicated processing such as manual selection, it is suitable for practical use, and a large amount of processing is possible. Furthermore, by crushing the battery materials almost collectively, each other acts as a grinding medium, and crushing, grinding and peeling are promoted. Moreover, since high-grade aluminum and copper can be recovered from the current collector, the battery recycling rate can be improved.

Process drawing which shows an example of the processing method of this invention

Examples of the present invention are shown below. In addition, the analysis of metal components, such as copper, aluminum, manganese, was measured with the inductively coupled plasma emission spectrometer after completely dissolving using aqua regia and sulfuric acid.

[Example 1]
The electrolyte solution was washed and the used lithium ion secondary battery that had been rendered harmless was dried, and the separator and the outer package were separated and removed to prepare a sample as a mixture of only the positive electrode material and the negative electrode material. About this sample, the mixture of a positive electrode material and a negative electrode material was used for the biaxial crusher, and was roughly crushed (primary crushing) into about several cm pieces. Further, this coarsely crushed material was subjected to a high-speed mill and secondarily crushed to 1 mm or less at 5 000 rpm. This secondary crushed material is divided into fine crushed material (fine particle) of 0.5 mm or less and crushed material of medium size (medium particle) of 0.5 mm or more using a vibrating sieve having an aperture of 0.5 mm. Separated. When the components of various crushed materials were analyzed, the weight ratio (peeling rate) of the separated active material to the total weight of the applied active material was 97.8 wt% for the positive electrode active material and about 100 wt% for the negative electrode active material. It was confirmed.
Further, the medium particles were put into a vibration sieve and classified into 0.5 mm to 1 mm. The crushed material of 1 mm or more was again subjected to a high speed mill, and pulverization was repeated to adjust the particle size to 0.5 mm to 1 mm. The classified crushed material was subjected to an air table and subjected to specific gravity selection under conditions of a side slope angle of 4 °, an end slope angle of 12 °, a frequency of 10 Hz, and an airflow condition of 1 m / sec. Analysis of the components of the collected light and heavy materials showed that the composition of the feed sample of the raw material was an Al amount of 25.0 wt% and a Cu amount of 75.0 wt%, whereas the light weight Al amount of 95.9 wt% And Cu content 4.1%, Al content 1.2% by weight and Cu content 97.8% by weight, it can be recovered by concentrating aluminum in a light product and concentrating copper in a heavy product. It was. In addition, the aluminum recovery rate at this time (aluminum weight in the light material / total aluminum weight contained in the input sample) was 88%, and the copper recovery rate (copper weight in the heavy material / total copper weight contained in the input sample). ) Was 96%, and the overall separation efficiency (aluminum recovery rate + copper recovery rate−100%), which is an evaluation index for separation, was as high as 92%. . Table 1 shows the processing conditions and results.

[Example 2]
The coarsely crushed material (primary crushed material) of Example 1 was subjected to a high-speed mill and secondarily crushed to 20 mm or less and 10 mm or less. This secondary crushed material was separated into fine particles having a size of 0.5 mm or less and medium particles having a size larger than 0.5 mm using a vibrating sieve having an opening of 0.5 mm. Table 2 shows the peeling rate of the positive electrode active material in this case. In the secondary crushing to 20 mm or less and 10 mm or less, the peeling rate of the positive electrode active material is 90% or less, and when the secondary crushing to 5 mm or less, the peeling rate is 97% or more. In order to prevent the current collector from being excessively crushed and the particle size to be 0.5 mm or less, the secondary pulverization is preferably kept on a 5 mm basis. The peel rate of the positive electrode active material is the weight of the peeled positive electrode active material / the total weight of the positive electrode active material applied to the current collector.

Example 3
Specific gravity selection was performed under the same conditions as in Example 1 while maintaining the particle size of 0.5 mm to 5 mm as it was without categorizing and repeatedly crushing the medium particles in Example 1. Alternatively, the medium-sized product of Example 1 is put into a vibrating sieve and classified into 0.5 mm to 2 mm, and crushed material of 2 mm or more is again subjected to a high-speed mill, and crushing is repeated to adjust the particle size to 0.5 mm to 2 mm. Specific gravity sorting was performed in the same manner as in Example 1. The results are shown in Table 3. The 0.5 mm to 1 mm classified product has the highest overall separation efficiency. Therefore, it is preferable to subject the sample to specific gravity sorting with a limited particle size such as 0.5 mm to 1 mm.
The total separation efficiency is (aluminum recovery rate + copper recovery rate-100%). The aluminum recovery rate is (the weight of aluminum in the lightweight material / the total weight of aluminum contained in the charged sample). The copper recovery rate is (copper weight in heavy article / total copper weight contained in sample put in).

The method for treating a lithium ion battery of the present invention is useful in the treatment business of a large amount of used batteries generated from the automobile industry and the like.

Claims (7)

The mixture of the positive electrode material and the negative electrode material of the used lithium ion battery is crushed to a few mm or less, the active material is peeled off from the current collector of the electrode material, the crushed mixture is sieved, and the crushed current collector is The medium-sized material and the active material crushed material are separated into the main fine particles, and the fine particles are collected. A method for treating a used lithium ion battery, which is separated and collected.
The coarsely crushed mixture obtained by roughly crushing the mixture of the positive electrode material and the negative electrode material is further subjected to secondary crushing to obtain coarse particles having a particle size of more than 5 mm, medium particles of 5 mm or less to 0.5 mm or more, and less than 0.5 mm. The processing method of a used lithium ion battery according to claim 1, which is sieved to fine particles.
(I) Select the specific gravity as it is, (b) Classify the specific gravity by classifying it to 2 mm or less to 0.5 mm or more, or (c) Classify it to 1 mm or less to 0.5 mm or more. The method for treating a used lithium ion battery according to claim 1 or 2, wherein the specific gravity is selected.
Roughly pulverize the mixture of the positive electrode material and negative electrode material of the used lithium ion battery, or after detoxifying the mixture, coarsely pulverize it, and further remove the resin by water tank or wind sorting. The crushed mixture is further subjected to secondary crushing, and sieved to coarse particles having a particle size of more than 5 mm, medium particles having a particle size of 5 mm or less to 0.5 mm or more, and fine particles having a particle size of less than 0.5 mm. The processing method of the used lithium ion battery in any one of Claim 3.
The processing method of a used lithium ion battery according to any one of claims 1 to 4, wherein the battery including the magnetic deposit is subjected to magnetic separation of the coarsely crushed mixture after the coarse crushing to remove the magnetic deposit and then secondary pulverized.
The method for treating a used lithium ion battery according to any one of claims 1 to 5, wherein combustible substances contained in the battery are sieved into coarse particles.
The recovered fine particles are used as raw materials for cobalt, nickel, manganese, and lithium, the recovered lightweight materials are used as aluminum materials, and the recovered heavy materials are reused as copper materials, respectively. A method for treating a used lithium ion battery as described.

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