JP6100991B2 - Method for recovering valuable material from positive electrode of lithium ion secondary battery - Google Patents

Description

  The present invention easily recycles valuable materials such as cobalt and nickel from the defective lithium ion secondary battery generated during the manufacturing process, and the positive electrode of the lithium ion secondary battery that is discarded with the life of the device and battery used. The present invention relates to a method for recovering valuable materials from the positive electrode of a lithium ion secondary battery that can be recovered in a usable state.

Lithium ion secondary batteries are lighter, higher capacity, and higher electromotive force secondary batteries than conventional lead-acid batteries and nickel-cadmium secondary batteries, and are widely used in mobile devices such as mobile phones and laptop computers. Has been.
As a positive electrode material for such a lithium ion secondary battery, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), nickel-manganese-cobalt-based oxides, and the like are used. Cobalt and nickel are included. Therefore, it is desired to recover these valuable materials from the used lithium ion secondary battery and to recycle them as a positive electrode material for the lithium ion secondary battery.

Then, the secondary processing which heats the metal foil coating waste material of the secondary battery in which the electrode material containing a metal compound is coated on the metal foil to a temperature of 300 ° C. to 600 ° C. in an oxygen-containing gas stream is subjected to a combustion treatment. A combustion treatment method for metal foil coating waste materials of batteries has been proposed (see Patent Document 1).
However, in the proposed technique, the recovered material containing cobalt and nickel contains a large amount of aluminum as a current collector. Therefore, the recovered material cannot be used as it is as a reuse material of cobalt and nickel. For this reason, in order to use the recovered material as a reused raw material, more processes are required, and there is a problem that the recovery process becomes complicated.

  Therefore, the provision of a method for recovering valuable materials from the positive electrode of a lithium ion secondary battery that can easily and efficiently recover reused materials containing valuable materials such as cobalt and nickel from the positive electrode of the lithium ion secondary battery. Is currently required.

Japanese Patent Laid-Open No. 10-8150

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, the present invention relates to a valuable material from a positive electrode of a lithium ion secondary battery that can easily and efficiently recover a reused raw material containing valuable materials such as cobalt and nickel from the positive electrode of the lithium ion secondary battery. The purpose is to provide a collection method.

Means for solving the problems are as follows. That is,
<1> A heating step of heating a positive electrode of a lithium ion secondary battery containing a current collector and a valuable material at 500 ° C. to 650 ° C .;
And sieving the positive electrode after the heating step to obtain a recovered product containing the valuables and having a current collector content of 2% by mass or less. This is a method for recovering valuable materials from the positive electrode of the secondary battery.
<2> The method for recovering a valuable material from the positive electrode of the lithium ion secondary battery according to <1>, wherein the heating temperature in the heating step is 590 ° C to 610 ° C.
<3> The method for recovering a valuable material from the positive electrode of the lithium ion secondary battery according to any one of <1> to <2>, wherein the current collector is aluminum.
<4> The method for recovering a valuable material from the positive electrode of the lithium ion secondary battery according to any one of <1> to <3>, wherein the valuable material is at least one of cobalt and nickel.
<5> The lithium ion ion according to any one of <1> to <4>, wherein the sieve selection step uses a sieve having a mesh opening of 2.0 mm or less to obtain a recovered material under the sieve. This is a method for recovering valuable materials from the positive electrode of the secondary battery.

  According to the present invention, lithium that can solve the above-described problems and can easily and efficiently recover a reused raw material containing valuables such as cobalt and nickel from the positive electrode of a lithium ion secondary battery. A method for recovering valuable materials from the positive electrode of an ion secondary battery can be provided.

Figure 3 is a graph showing the relationship between the particle size and mass integrated value of relationship and recovery of particle size and concentration of aluminum recovered was in the third embodiment.

(Recovery method of valuable materials from positive electrode of lithium ion secondary battery)
The method for recovering valuable materials from the positive electrode of the lithium ion secondary battery of the present invention includes at least a heating step and a sieve sorting step, and further includes other steps as necessary.

<Heating process>
The heating step is not particularly limited as long as it is a step of heating the positive electrode of the lithium ion secondary battery at 500 ° C. to 650 ° C., and can be appropriately selected according to the purpose.

-Lithium ion secondary battery-
The lithium ion secondary battery is not particularly limited and may be appropriately selected depending on the purpose. For example, a defective lithium ion secondary battery generated in the process of manufacturing a lithium ion secondary battery, used equipment Examples thereof include a lithium ion secondary battery that is discarded due to a defect, a life of a device used, a used lithium ion secondary battery that is discarded due to a life.

  The structure of the lithium ion secondary battery is not particularly limited as long as it has a positive electrode structure, and can be appropriately selected according to the purpose. For example, the positive electrode, the negative electrode, the separator, the electrolyte, and the organic solvent And a battery case made of metal containing the positive electrode, the negative electrode, the separator, and the electrolytic solution.

  There is no restriction | limiting in particular as a shape of the said lithium ion secondary battery, According to the objective, it can select suitably, For example, a cylindrical shape, a button shape, a coin shape, a square shape, a flat shape etc. are mentioned.

--- Positive electrode-
The positive electrode is not particularly limited as long as it is a positive electrode containing a current collector and a valuable material, and can be appropriately selected according to the purpose. For example, the current collector is applied to the current collector. And a positive electrode provided with a positive electrode material containing a valuable material.
There is no restriction | limiting in particular as a shape of the said positive electrode, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

---- Current collector ---
There is no restriction | limiting in particular as said collector, According to the objective, it can select suitably, For example, metals, such as aluminum, copper, iron, nickel, titanium, stainless steel, etc. are mentioned. Among these, aluminum is preferable in that separation from valuable materials by sieving is easy, and the content of the current collector in the obtained recovered product can be easily reduced.
There is no restriction | limiting in particular as a shape of the said collector, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

---- Positive electrode material ---
The positive electrode material is not particularly limited as long as it contains the valuable material, and can be appropriately selected according to the purpose. For example, the positive electrode material includes at least a positive electrode active material containing the valuable material, and if necessary, a conductive agent. And a positive electrode material containing a binder resin.
There is no restriction | limiting in particular as said valuable material, Although it can select suitably according to the objective, It is preferable that it is at least any one of cobalt and nickel.
Examples of the positive electrode active material include lithium cobalt oxide (LiCoO ₂ ), lithium cobalt nickel oxide (LiCo _1/2 Ni _1/2 O ₂ ), and LiNi _x Co _y Mn _z O _{2 (x + y + z)} .
There is no restriction | limiting in particular as said electrically conductive agent, According to the objective, it can select suitably, For example, carbon black, a graphite, a carbon fiber, a metal carbide etc. are mentioned.
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a homopolymer or copolymer such as vinylidene fluoride, tetrafluoroethylene, acrylonitrile, ethylene oxide, styrene-butadiene, etc. For example, rubber.

  The heating step is performed on the positive electrode taken out from the battery case of the lithium ion secondary battery. The method for taking out the positive electrode from the battery case is not particularly limited and may be appropriately selected depending on the purpose. For example, the battery case (battery housing) is disassembled using a tool such as a pliers or a cutter. And a method of taking out the positive electrode in the battery case.

-Heating-
The heating temperature is 500 ° C. to 650 ° C., preferably 590 ° C. to 610 ° C. When the heating temperature is less than 500 ° C., the binder resin and the like contained in the positive electrode are not sufficiently decomposed, so that it is difficult to separate the current collector from the valuable material in the sieve sorting step. Become. When the heating temperature exceeds 650 ° C., the current collector such as aluminum is oxidized and becomes brittle, so that it is difficult to separate the current collector from the valuable material in the sieve sorting step. In other words, since the current collector becomes brittle and thin, it is difficult to separate the current collector and the valuable material in the sieve selection step because the current collector and the valuable material are recovered together under the sieve. become. When the heating temperature is within the preferable range, it is advantageous in that the yield of recovered material that can be used as a reused raw material is high while suppressing energy used for heating.

  Here, the heating temperature refers to the temperature of the gas around the positive electrode during heating, for example, the temperature of the gas in the vicinity where the positive electrode is disposed in the heating furnace during heating.

  There is no restriction | limiting in particular as said heating time, Although it can select suitably according to the objective, 0.5 to 6 hours are preferable and 0.5 to 1 hour are more preferable.

  The heating is preferably performed using a furnace. There is no restriction | limiting in particular as said furnace, According to the objective, it can select suitably, For example, batch type furnaces, such as a rotary kiln furnace, a fluidized bed furnace, a tunnel furnace, a muffle, a cupola, a stalker furnace, etc. are mentioned. In the present invention, since heating can be performed even in an air atmosphere, for example, a commonly used furnace such as a rotary kiln furnace can be used, and the selection range of the furnace is widened.

  In addition, since the binder resin in the positive electrode is usually an organic substance, it is thermally decomposed by the heating and hardly contained in the recovered material.

<Screening process>
As the sieving selection step, if the positive electrode after the heating step is sieved to obtain a recovered material containing the valuables and having a current collector content of 2% by mass or less, There is no restriction | limiting, According to the objective, it can select suitably.

  By setting the content of the current collector in the recovered material to 2% by mass or less, the recovered material containing the valuable material can be used as a reuse raw material. When the content of the current collector in the recovered material exceeds 2% by mass, a step of removing the current collector from the recovered material when the recovered material is reused, for example, a step of sorting aluminum, etc. It becomes necessary and the process at the time of reuse becomes complicated.

-Sieving-
There is no restriction | limiting in particular as said sieving, According to the objective, it can select suitably, For example, it can carry out using a vibration sieve, a multistage vibration sieve, a cyclone, the standard sieve of JISZ8801, etc.
By the sieving, the current collector and the valuable material are separated, and a recovered material containing the valuable material and having a content of the current collector of 2% by mass or less is obtained.
There is no restriction | limiting in particular as opening of the mesh of a sieve, Although it can select suitably according to the objective, 2.0 mm or less is preferable, 1.2 mm or less is more preferable, 0.6 mm or less is especially preferable. That is, it is preferable to obtain the recovered product under a sieve having a sieve mesh opening of 2.0 mm or less, and obtaining the recovered product under a sieve having a sieve mesh opening of 1.2 mm or less. More preferably, it is particularly preferable to obtain the recovered material under a sieve having a sieve mesh opening of 0.6 mm or less. If the mesh opening exceeds 2.0 mm, the content of the current collector in the recovered product may increase.
The sieving may be dry or wet.

<Other processes>
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a crushing process, a concentration process, etc. are mentioned.

-Crushing process-
The pulverization step is not particularly limited as long as it is a step before the sieve selection step and after the heating step without pulverizing the current collector and pulverizing the positive electrode. You can choose.
By performing the pulverization step, in the sieving selection step, the separation efficiency of the current collector and the valuable material is improved, and the yield of the recovered product obtained is increased.
In the normal pulverization, the current collector such as aluminum is not stretched and pulverized. On the other hand, the positive electrode material containing the valuable material is easily pulverized by the heating step. For example, a hammer crusher, a rod mill, a ball mill, a jaw crusher, a roll crusher, a cutter mill, or a rotary crusher can be used.

-Concentration process-
The concentration step is not particularly limited as long as it is a step of concentrating the valuables in the recovered product after the sieve sorting step, and can be appropriately selected according to the purpose. For example, the recovered product And a step of mixing and baking, and washing with water.
There is no restriction | limiting in particular as temperature of the said baking, Although it can select suitably according to the objective, 650 to 800 degreeC is preferable.
By performing the concentration step, it is possible to increase the concentration of the valuables in the recovered material and obtain a recovered material more suitable for reuse.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

( Reference Example 1)
<Recovery of valuable materials>
A used lithium ion secondary battery for a personal computer was used.
The used lithium-ion secondary battery for personal computers was disassembled with a tool, and the positive electrode was taken out from the battery case. A total amount of 1,000 g of the extracted positive electrode contained 100 g of an aluminum foil as a current collector and 900 g of a positive electrode material containing a valuable material.

-Heating process-
1,000 g of the positive electrode was placed in a box furnace (manufactured by Koyo Thermo Systems Co., Ltd.), the heating temperature was 500 ° C. (in-furnace temperature), and the temperature was raised to 500 ° C. at a temperature rising rate of 10 ° C./min. After reaching the temperature, it was heated for 1 hour. The atmosphere in the furnace was an air atmosphere.

-Screening process-
The heated positive electrode is a multi-stage sieve (7 stages) in which sieves of 0.075 mm, 0.15 mm, 0.3 mm, 0.6 mm, 1.2 mm, 2.0 mm, and 10 mm are stacked in this order. And screened.

The aluminum concentration (Al concentration) was determined for each sieve and the recovered material after sieving. Moreover, the mass integration value from the finer particle size was calculated | required about those collect | recovered materials. The results are shown in FIG.
In addition, about aluminum concentration, it calculated | required by ICP emission-spectral-analysis (The product made by Perkin Elmer, Optima3300XL).
The particle size was calculated based on the sieve mesh. That is, for the recovered material that passed through a sieve having a sieve mesh of 0.075 mm, the particle size was set to “0.075 mm or less” (in the drawing, expressed as “˜0.075”). For the recovered material that passed through the sieve having a sieve mesh of 0.15 mm and the sieve mesh remaining on the sieve of 0.075 mm, the particle size was “over 0.075 mm and not more than 0.15 mm” (in the figure, It is expressed as “0.15 / 0.075”).
Moreover, in the sieve selection by the multistage sieve, the ratio (mass ratio) of the recovered material having a current collector content of 2% by mass or less to the total recovered material is shown in Table 1 and FIG.

(Reference Example 1-2, 6, Example 3-5, and Comparative Examples 1 and 2)
In Reference Example 1, valuable materials were collected in the same manner as Reference Example 1 except that the heating temperature was changed to the heating temperature shown in Table 1.
The aluminum concentration (Al concentration) was determined for each sieve and the recovered material after sieving. Moreover, the mass integration value from the finer particle size was calculated | required about those collect | recovered materials. The results are shown in FIGS.
Moreover, in the sieve selection by the multistage sieve, the ratio (mass ratio) of the recovered material having a current collector content of 2% by mass or less to the total recovered material is shown in Table 1 and FIG.

In Reference Examples 1 to 2 and 6 and Examples 3 to 5, from the results shown in FIGS. 1 to 6 and 9 and Table 1, a recovered material having a current collector content of 2 mass% or less, that is, a recycled material can be recovered. And the mass ratio in the collection | recovery thing after sieve screening was about 40 mass% or more, and it was able to collect | reuse a reuse raw material with high efficiency.
In particular, in Examples 3 to 5 in which the heating temperature was 590 ° C. to 610 ° C., a recovered material with higher efficiency and a current collector content of 2% by mass or less could be recovered.

  Further, it was confirmed by SEM-EDX analysis (manufactured by KEYENCE, VE-9800) that the recovered material contains valuable materials. The analysis results of the recovered material (particle size of 0.075 mm or less) remaining under the sieve having a mesh size of 0.075 mm in Example 4 are shown in FIGS. 10A to 10C. FIG. 10A is a SEM photograph of the recovered material. FIG. 10B is a cobalt (Co) mapping image of the recovered material. FIG. 10C is a nickel (Ni) mapping image of the recovered material. From these results, it was confirmed that the recovered material contains cobalt and nickel which are valuable materials.

  The method for recovering valuable materials from the positive electrode of the lithium ion secondary battery according to the present invention is capable of easily and efficiently recovering reused raw materials containing valuable materials such as cobalt and nickel from the positive electrode of the lithium ion secondary battery. Therefore, the method can be suitably applied to a method for recovering valuable materials from a used lithium ion secondary battery.

Claims (3)

A heating step of heating a positive electrode of a lithium ion secondary battery containing a current collector and a valuable material at 590 ° C. to 610 ° C. for 0.5 hours to 6 hours in an air atmosphere ;
Sieving the positive electrode after the heating step, and a sieving step for obtaining a recovered material containing the valuables and having a current collector content of 2% by mass or less,
The current collector is aluminum;
The valuable material is at least one of cobalt and nickel;
The mass ratio of the recovered material containing the valuable material and the content of the current collector of 2% by mass or less is 40% by mass or more based on the total amount of the recovered material,
The sieve screening step uses a sieve having a sieve mesh opening of 1.2 mm or more and 2.0 mm or less, and obtains a recovered material under the sieve. Collection method of things. 2. The lithium according to claim 1, wherein in the heating step, a positive electrode of a lithium ion secondary battery containing a current collector and a valuable material is heated at 600 ° C. to 610 ° C. for 0.5 hour to 1 hour in an air atmosphere. A method for recovering valuable materials from the positive electrode of an ion secondary battery. 3. The lithium ion according to claim 2, wherein a mass ratio of a recovered material containing the valuable material and having a current collector content of 2 mass% or less is 75.8 mass% or more based on a total amount of the recovered material. A method for recovering valuable materials from the positive electrode of a secondary battery.