JP2019185999A - Lithium ion battery heating processing device and processing method for lithium ion battery - Google Patents

Abstract

To collect a rare metal such as cobalt and a general-purpose metal such as copper or aluminum with high purity and high yield only by crushing and sieving a processed lithium ion battery while preventing a housing of the lithium ion battery from being ruptured and the aluminum, etc., from being embrittled and micronized in thermal processing of the lithium ion battery.SOLUTION: A heating space area in which a battery gas is made flow out of a housing by heating a lithium ion battery and a thermal processing space area in which thermal processing is performed on the lithium ion battery after the outflow of the battery gas are separated inside of a heating furnace. With regard to the thermal processing space area, overheat steam at 450°C to 750°C is injected only into the thermal processing space area by multiple injection nozzles. The overheat steam is sucked by a blower while preventing contact with the lithium ion battery existing in the heating space area. At such a time, suction output of the blower is regulated in such a manner that a flow of the overheat steam passing the inside of the heating space area becomes a laminar flow.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lithium ion battery heat treatment apparatus and a lithium ion battery treatment method, and more specifically, a heat treatment apparatus and a lithium ion battery treatment method (recovery of valuable metals) used when recovering valuable materials from lithium ion batteries. Method).

A lithium ion battery has a feature that it has a high energy density and can obtain a relatively high voltage. For this reason, lithium ion batteries are widely used as electronic devices such as notebook computers, video cameras, digital cameras, tablet terminals, mobile phones, and in-vehicle batteries.
A lithium ion battery includes a housing (case) and a metal case in which a positive electrode, a negative electrode, an electrolytic solution, a separator, and the like are enclosed. Aluminum and resin are often used for the case. Iron and aluminum are often used for metal cases. The positive electrode is composed of a positive electrode current collector made of aluminum foil and a positive electrode active material made of a lithium composite oxide such as LiCoO ₂ , LiNiO _2, and LiMn ₂ O ₄ bonded to the surface thereof via a binder. The negative electrode is typically composed of a negative electrode active material made of a copper negative electrode current collector and a carbon material such as graphite bonded to the surface thereof. The electrolytic solution is generally a lithium salt dissolved in a non-aqueous solution such as ethylene carbonate or propylene carbonate. Generally, polyethylene, polypropylene or the like is used for the separator.

In recent years, with the increase in the amount of use of lithium ion batteries and the expansion of the range of use, the amount discarded due to the product life of the batteries and defects in the manufacturing process has increased. Under such circumstances, it is desired to easily recover valuable metals such as nickel and cobalt from lithium ion batteries that are discarded in large quantities at a relatively low cost.
In a conventional recovery process, a lithium ion battery is roasted at a relatively high temperature of about 600 ° C. to 700 ° C., and then crushed and sieved. Since sorting was performed, other components were actually mixed in the magnetized material in the form of being wound in the magnetized cobalt. In addition to the fact that the lithium ion battery was roasted at a high temperature exceeding, for example, 660 ° C., the case of the lithium ion battery was ruptured during roasting, and aluminum and the like became brittle and refined. It is considered that the aluminum melted at a high temperature exceeding the melting point involved the positive electrode material. In addition, the magnetic deposit contains a large amount of aluminum to be separated most, and the recovery rate of valuable metals such as cobalt cannot be improved significantly.

As a method for solving such technical problems, a technique described in Patent Document 1 has been proposed.
The technique described in Patent Document 1 discloses a method of treating a lithium ion battery encased in a casing containing aluminum. After heating the temperature of the lithium ion battery to 400 ° C. to 550 ° C., the lithium ion battery Is crushed and sieved, and then powder heated to 550 ° C to 700 ° C.

JP 2017-37807 A

  However, according to the technique described in Patent Document 1, the lithium ion battery is once heated to 400 ° C. to 550 ° C., then machined, and further heated at a powder of 550 ° C. to 700 ° C. Moreover, the efficiency is very bad.

  Therefore, the inventor paid attention to the structure of the lithium ion battery and the structure of the heat treatment apparatus, and divided the inside of the heating furnace into a heating space region that is a low temperature region and a heat treatment space region that is a high temperature region, The present invention has been completed by discovering that the above-mentioned problems can be solved if a high-temperature heat source (heat medium) is not applied to the lithium ion battery existing in the battery.

  In the heat treatment of a lithium ion battery, the present invention prevents the lithium ion battery casing from rupturing and aluminum and the like from becoming brittle and becoming finer, and only crushing and sieving the treated lithium ion battery. An object of the present invention is to provide a lithium ion battery heat treatment apparatus in which rare metals such as cobalt and general-purpose metals such as copper and aluminum can be recovered with high purity and high yield.

  According to the first aspect of the present invention, the internal space of the heating furnace constituted by the furnace wall heats the lithium ion battery encased in the casing containing aluminum, so that the battery gas is discharged from within the casing of the lithium ion battery. And a heat treatment space region for heat-treating the lithium ion battery after the battery gas has flowed out, and the lithium ion battery is introduced into the heating space region from an inlet, and the heat treatment space A lithium-ion battery heat treatment apparatus that is discharged to a discharge port through a region, wherein the heat treatment space region is provided with a plurality of injection nozzles that inject superheated steam at 450 ° C. to 750 ° C. only into the heat treatment space region. In the heating space region, the superheated steam sprayed from the spray nozzle is transferred to the lithium ion battery existing in the heating space region. Suction to a blower is provided so as not to contact the suction output of the blower, the flow of superheated steam passing through the heating space region is a lithium ion battery heating device is adjusted to be laminar.

  According to a second aspect of the present invention, the spray nozzle is provided perpendicular to the inner wall surface of the furnace wall, and is arranged such that the length of the spray nozzle becomes longer as it is closer to the discharge port. The lithium ion battery heat treatment apparatus according to Item 1.

  According to a third aspect of the present invention, in the lithium ion battery according to the first or second aspect, the inner wall surface of the furnace wall is provided with a protruding portion that separates the heating space region and the heat treatment space region. It is a heat treatment apparatus.

  The invention according to claim 4 is a method of treating a lithium ion battery for recovering valuable metals from a lithium ion battery, wherein the lithium ion battery is heated by heating the lithium ion battery enclosed in a casing containing aluminum. A battery gas outflow step for discharging the battery gas from the inside of the housing, a heat treatment step for heat treating the lithium ion battery after the battery gas outflow, and crushing the lithium ion battery after the heat treatment step, followed by sieving A sieving and sorting step, wherein the battery gas outflow step and the heat treatment step are continuously performed using the lithium ion battery overheat treatment device according to any one of claims 1 to 3. It is a processing method.

  The invention according to claim 5 is the method for treating a lithium ion battery according to claim 4, wherein the temperature of the lithium ion battery in the battery gas outflow step is 250 ° C. or less.

According to the present invention, the inside of the heating furnace is divided into a heating space region and a heat treatment space region. Overheated steam at 450 ° C. to 750 ° C. is injected only into the heat treatment space region by the plurality of injection nozzles in the heat treatment space region. The injected superheated steam is sucked by a blower so as not to contact the lithium ion battery existing in the heating space region. At this time, the suction output of the blower is adjusted so that the flow of superheated steam passing through the heating space region becomes a laminar flow.
By comprising in this way, the temperature of a lithium ion battery can be suppressed to about 250 degreeC.

The cause of rupture due to heating of the lithium ion battery is mainly due to the lithium ion battery being placed at a very high temperature, and the electrolyte (volatile organic solvent) enclosed in the lithium ion battery is vaporized, resulting in battery gas. This is because the volume of the battery gas rapidly increases (expands). The boiling point of this electrolytic solution is about 260 ° C., even if the electrolytic solution is a high boiling point solvent, and is usually 200 ° C. or lower. By suppressing the temperature of the lithium ion battery to about 250 ° C., it is possible to prevent the temperature of the electrolyte from becoming high, and although the electrolyte is vaporized to generate battery gas, the volume of the battery gas increases rapidly. There is nothing. For this reason, in the heat treatment of the lithium ion battery, it is possible to prevent the casing of the lithium ion battery from being ruptured and aluminum and the like becoming brittle and becoming finer.
The battery gas is a gas generated in the metal case of the lithium ion battery by heating the lithium ion battery and released to the outside. In the present invention, the battery gas is an electrolyte solution (volatile organic) enclosed in the lithium ion battery. The main thing is that the solvent is vaporized.

The lithium ion battery in the present invention is not particularly limited as long as it is encased in a casing containing aluminum and can be used in various electronic devices such as mobile phones. In particular, it is preferable from the viewpoint of effective utilization of resources to target so-called lithium ion battery scrap that is discarded due to the life of the battery product, manufacturing defects, or other reasons.
Examples of the casing of the lithium ion battery include those made only of aluminum and those containing aluminum, iron, aluminum laminate, and the like.
In the lithium ion battery, a positive electrode active material made of a composite metal oxide of one or more metals of lithium, nickel, cobalt, and manganese, or a positive electrode active material in the above casing is, for example, polyvinylidene fluoride (PVDF). It may include an aluminum foil (positive electrode current collector) applied and fixed by another organic binder or the like. In addition, the lithium ion battery may contain copper, iron, and the like.
Furthermore, a lithium ion battery generally includes an electrolytic solution in a casing, and for example, ethylene carbonate, propylene carbonate, or the like may be used as the electrolytic solution.

A heating space area | region says the area | region (compartment) in which the insertion port and the blower were provided among the insides of the heating furnace comprised with the furnace wall. In the heating space region, the lithium ion battery is heated so that the lithium ion battery has a temperature of about 260 ° C., and a heat outflow process is performed in which the battery gas flows out from the inside of the casing of the lithium ion battery.
The superheated steam (heat source, heat medium) does not directly contact the lithium ion battery existing in the heating space region. Since the heating of the lithium ion battery is performed by the residual heat of the heat treatment in the heat treatment space region, the heating temperature of the lithium ion battery is about 250 ° C.

The heat treatment space region refers to a region (section) in which a discharge port and a plurality of injection nozzles are provided in the inside of the heating furnace constituted by the furnace wall. In the heat treatment space region, the lithium ion battery after the battery gas flows out is heat-treated with superheated steam at 450 ° C. to 750 ° C. Heat treatment means removing the electrolyte inside the lithium-ion battery and vaporizing it, and decomposing the binder that binds the aluminum and the positive electrode material and the resin in the housing. Aluminum during crushing and sieving The separation of the positive electrode material and the positive electrode material are promoted to effectively separate and remove aluminum, and the recovery rate of the positive electrode material recovered under the sieve is increased.
The cross-sectional shape, diameter, and length of the injection nozzle are arbitrary, and may be the same cross-sectional shape, the same diameter, and the same length, or may have different cross-sectional shapes, different diameters, and different lengths. . However, from the viewpoint of facilitating the control of the flow of steam and improving the efficiency of the heat treatment of the lithium ion battery, the injection nozzle is provided perpendicular to the inner wall surface of the furnace wall, and the closer to the discharge port, the more It is preferable to arrange the nozzles to be long.

  The blower is provided in the heating space region. The blower type or the like is arbitrary, but the superheated steam is provided so as not to come into contact with the lithium ion battery existing in the heating space region. The suction output of the blower is adjusted so that the flow of superheated steam passing through the heating space region becomes a laminar flow. Laminar flow of superheated steam means that the temperature in the heating space region does not become uniform due to the flow of superheated steam, and the superheated steam existing in the heat treatment space region flows in a substantially straight line by the blower. .

  The inner wall surface of the furnace wall has a protruding portion at the boundary between the heating space region and the heat treatment space region so that the lithium ion battery in the heating space region that is being heated and discharged is not carelessly moved to the heat treatment space region. May be provided. This protrusion has a height that allows the lithium ion battery that is being heated and discharged to inadvertently move to the heat treatment space region, and that the lithium ion battery after the heat and flow treatment can move to the heat treatment space region.

  According to the present invention, by suppressing the temperature of the lithium ion battery to about 250 ° C., it is possible to prevent the temperature of the electrolytic solution from rapidly increasing. Thereby, in the heat treatment of the lithium ion battery, it is possible to prevent the casing of the lithium ion battery from being ruptured, and aluminum or the like becoming brittle and becoming finer. As a result, a rare metal such as cobalt and a general-purpose metal such as copper or aluminum can be recovered with high purity and high yield by simply crushing and sieving the treated lithium ion battery.

  In particular, according to the second aspect of the present invention, the superheated steam is provided by being arranged so as to be perpendicular to the inner wall surface of the furnace wall and so that the length of the injection nozzle becomes longer as it is closer to the discharge port. Can be easily controlled, and the efficiency of the heat treatment of the lithium ion battery can be improved.

  Further, according to the invention described in claim 3, by providing the protrusion on the inner wall surface of the furnace wall, the lithium ion battery in the heating space region during the heat outflow treatment is inadvertently moved to the heat treatment space region. Can be inhibited. For this reason, in the heat treatment of the lithium ion battery, it is possible to further prevent the casing of the lithium ion battery from being ruptured and the aluminum or the like from becoming brittle and becoming finer.

It is sectional drawing which shows the lithium ion battery heat processing apparatus which concerns on the Example of this invention.

Examples of the present invention will be described in detail below.
As shown in FIG. 1, a lithium ion battery heat treatment apparatus 10 according to an embodiment of the present invention is disposed inside a heating apparatus body 11 having a rotating cylindrical furnace wall and the heating apparatus body 11. A superheated steam pipe 12 having a length that is 3/4 of the length of the furnace wall, a plurality of injection nozzles 13 protruding at equal intervals from the superheated steam pipe, and heating A suction duct 14 fixed to the apparatus main body 11 is provided. Further, the lithium ion battery heating device 10 includes a raw material supply unit 16 provided with a raw material supply feeder 15 for introducing a lithium ion battery into the heating device main body 11, and a discharge unit 17 for discharging the lithium ion battery after thermal decomposition. I have.

The heating device main body 11 is made of castable concrete in a cylindrical shape, and includes a furnace wall provided with castable concrete side walls at both ends. That is, the heating device main body 11 has a circular sealed internal space as viewed from the side. And the iron surface coating | covering material is provided in the outer wall surface of the furnace wall.
The raw material supply unit 16 is fixed to one side of the two side walls of the heating device main body 11, and the discharge unit 17 is fixed to the other side.
The raw material supply unit 16 is provided with a supply port for supplying the lithium ion battery to the inside of the heating apparatus main body 11, and a supply lid for opening and closing the supply port mechanically or electromagnetically is attached. This supply lid opens and closes the supply port physically (mechanically) or electromagnetically. The raw material supply unit 16 is provided with a raw material supply feeder 15 for supplying a raw material for supplying a lithium ion battery into the heating apparatus main body 11 through a supply port. The raw material supply feeder 15 has a vibrator, and when the raw material supply feeder 15 vibrates, the lithium ion battery moves into the heating device main body 11 while vibrating.
The discharge unit 17 is provided with a discharge port for discharging the heat-treated lithium ion battery to the outside of the heating device main body 11, and a discharge lid for opening or closing the discharge port mechanically or electromagnetically is attached. ing.

The superheated steam pipe 12 is a fixed (non-rotating) pipe that supplies superheated steam at 450 ° C. to 750 ° C. generated in a steam generator provided outside the heating apparatus body 11 to the inside of the heating apparatus body 11. . The superheated steam pipe 12 is provided so as to protrude from the side wall near the discharge unit 17 of the heating apparatus main body 11 toward the side wall near the raw material supply unit 16. The protruding length of the superheated steam pipe 12 is 3/4 of the length in the longitudinal direction of the heating device body 11 (that is, the separation distance between the two side walls). The end of the superheated steam pipe 12 is plugged. A plurality of injection nozzles fixed at equal intervals are provided on the tube wall of the superheated steam pipe 12.
The injection nozzle 13 is provided so as to be perpendicular to the superheated steam pipe and also perpendicular to the inner wall surface of the furnace wall of the heating apparatus body 11. The plurality of injection nozzles 13 have the same cross-sectional shape and the same diameter, but all have different lengths. The plurality of injection nozzles are arranged so that the length of the injection nozzle becomes longer as it is closer to the discharge port.

By configuring as described above, the inside of the heating apparatus main body 11 is divided into a heat treatment space region where steam is injected from the injection nozzle 13 and a heating space region which is other than that.
The suction duct 14 is provided in the heating space area of the heating device main body 11.
The suction duct 14 sucks, as a pyrolysis gas, a heat treatment gas or vapor released from the heat-treated lithium ion battery in the pyrolysis region. The suction output of the suction duct 14 is adjusted so that the superheated steam can be sucked so as not to contact the lithium ion battery existing in the heating space region. That is, the superheated steam that passes through the heating space region is sucked by the suction duct 14 in a substantially linear shape.

Using this lithium ion battery heat treatment apparatus 10, valuable metals were recovered from the waste lithium ion battery.
Specifically, the waste lithium ion secondary battery is put into the lithium ion battery heat treatment apparatus 10 so that the waste lithium ion battery stays in the heating space region for 5 to 20 minutes and in the heat treatment space region for 15 to 60 minutes. Heat treatment was performed. The superheated steam temperature was 750 ° C., the flow rate was 100 L / h, and the output of the suction duct 14 was 1200 m ³ / h. In addition, when the temperature of the heating space area | region was measured, it was 250-400 degreeC, and the burst sound emitted when the housing | casing of a waste lithium ion battery burst was not confirmed.
Moreover, when the temperature of the heat processing space area | region was measured, it was 400-550 degreeC.
After the heat treatment, the pyrolysis residue and pyrolysis gas are separated from the lithium ion battery heat treatment apparatus 10, so the pyrolysis residue is subjected to an impact crusher (hammer crusher, Yary type hammer crusher N0.3 manufactured by Yarya Machinery Co., Ltd.). Crushing treatment was performed, and then sieving was performed with a sieve mesh of 1.20 to 0.15 mm. Thereafter, the fine particles present under the sieve were analyzed in the sieving and the recovery rate was determined. As a result, 91.3% for cobalt, 7.0% for copper, and 6.3% for aluminum. And it analyzed about the coarse-grained substance which existed on the sieve in sieving, and when the recovery rate was calculated | required, it was 8.7% for cobalt, 93.0% for copper, and 93.7% for aluminum.

  Thus, the lithium ion battery heat treatment apparatus 10 according to the embodiment of the present invention prevents the casing of the lithium ion battery from being ruptured and the aluminum or the like from becoming brittle and becoming finer in the heat treatment of the lithium ion battery. I was able to. And just by crushing and sieving the treated lithium ion battery, it was possible to recover rare metals such as cobalt and general-purpose metals such as copper and aluminum with high purity and high yield.

Claims (5)

The internal space of the heating furnace formed by the furnace wall is
A heating space region for allowing battery gas to flow out from within the casing of the lithium ion battery by heating the lithium ion battery encased in the casing containing aluminum; and
A heat treatment space region for heat treating the lithium ion battery after the battery gas flows out;
A lithium ion battery heat treatment apparatus in which the lithium ion battery is charged into the heating space region from a charging port and discharged to the discharge port through the heat treatment space region,
The heat treatment space region is provided with a plurality of injection nozzles for injecting superheated steam at 450 ° C. to 750 ° C. only into the heat treatment space region,
The heating space region is provided with a blower that sucks the superheated steam ejected from the ejection nozzle so as not to contact the lithium ion battery existing in the heating space region,
The suction output of the blower is a lithium ion battery heat treatment apparatus that is adjusted so that the flow of superheated steam that passes through the heating space region becomes a laminar flow.   The lithium ion battery heating according to claim 1, wherein the injection nozzle is provided perpendicular to the inner wall surface of the furnace wall, and is arranged such that the length of the injection nozzle becomes longer as the discharge nozzle is closer to the discharge port. Processing equipment.   3. The lithium ion battery heat treatment apparatus according to claim 1, wherein a protrusion that separates the heating space region and the heat treatment space region is provided on an inner wall surface of the furnace wall. A method of treating a lithium ion battery for recovering valuable metals from a lithium ion battery,
A battery gas outflow step for causing the battery gas to flow out from within the casing of the lithium ion battery by heating the lithium ion battery encased in the casing containing aluminum; and
A heat treatment step of heat treating the lithium ion battery after the battery gas flows out;
Crushing the lithium-ion battery after the heat treatment step, and then sieving to perform sieving, and
The said battery gas outflow process and the said heat processing process are the processing methods of the lithium ion battery performed continuously using the lithium ion battery heat processing apparatus of any one of Claims 1-3.   The method for treating a lithium ion battery according to claim 4, wherein the temperature of the lithium ion battery in the battery gas outflow step is 250 ° C or lower.

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