Method and device for recovering valuable components in thermal runaway lithium ion battery

Abstract

The invention belongs to the technical field of resource recycling of retired lithium ion batteries, and discloses a method and a device for recycling valuable components in a thermal runaway lithium ion battery, and the method comprises the following steps: under negative pressure, the thermal runaway lithium ion battery is shredded and then crushed to obtain a first mixture consisting of thermal runaway black powder, a flaky current collector and a steel shell; the first mixture is separated through an iron removal device, and a steel shell and a second mixture are obtained; grading the second mixture through a cyclone separation device to obtain a flaky current collector and thermal runaway black powder; forming the thermal runaway black powder and water into ore pulp, and performing wet magnetic separation to obtain a magnetic ternary oxide and residual ore pulp; the remaining ore pulp is filtered and dried, and negative electrode graphite and lithium carbonate crystals are obtained; performing color sorting on the flaky current collector to obtain a copper sheet and an undissociated aluminum sheet; and grinding and screening the undissociated aluminum sheet to obtain the positive electrode black powder and the aluminum sheet. The treatment process is simple in flow, low in energy consumption and environmentally friendly, and the recovered valuable components are high in purity and high in recovery rate.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery of retired lithium-ion batteries, and in particular to a method and a device for recovering valuable components in a thermal runaway lithium-ion battery. Background Art

[0002] Lithium-ion batteries are used as the main power source for electric vehicles due to their high energy density. However, when lithium-ion batteries are used as the main power source for electric vehicles, there are certain safety hazards. Overcharging, overheating, and mechanical abuse of lithium-ion batteries can easily lead to internal short circuits, temperature rise, and induce thermal runaway risks. Thermal runaway is accompanied by more complex chemical reactions, producing various products including flammable gases and lithium carbonate; in addition, the positive electrode material will decompose to produce oxygen during the thermal runaway process, further exacerbating the reaction of flammable components such as the electrolyte. Current research on thermal runaway of lithium-ion batteries mainly focuses on the mechanism, inhibition, and safety prevention of thermal runaway, while less attention is paid to the recovery of valuable components in lithium batteries that have experienced thermal runaway.

[0003] In relatively mild systems such as conventional salt water and dielectric discharge, no violent chemical reactions occur inside lithium-ion batteries, and the positive and negative electrode materials, binders, current collectors, etc. remain in their original form.

[0004] At present, there are many studies and related invention patents on the recovery of valuable components in retired lithium-ion batteries with normal discharge. However, thermal runaway lithium-ion batteries are accompanied by complex chemical reactions during rapid energy release, mainly including the decomposition of SEI membrane and positive electrode materials, the reaction of negative electrode materials and electrolytes, and the deactivation and decomposition of binders. The material properties are greatly different from those of retired lithium-ion batteries with normal discharge. Among them, the wrapping of the binder on the positive electrode material and the prevention of its detachment from the surface of the current collector are difficulties that are difficult to bypass with existing recycling technologies. Regardless of whether pyrolysis, combustion or organic reagents are used to dissolve the binder, secondary pollution and high energy consumption are unavoidable, which in turn limits the recycling of valuable components from lithium batteries with thermal runaway. Summary of the invention

[0005] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a method and a device for recovering valuable components in a thermal runaway lithium-ion battery.

[0006] The method and device for recovering valuable components in a thermal runaway lithium-ion battery of the present invention are realized by the following technical solutions:

[0007] The first object of the present invention is to provide a method for recovering valuable components in a thermal runaway lithium-ion battery, comprising the following steps:

[0008] Step 1, shredding and crushing:

[0009] Under negative pressure, the thermal runaway lithium-ion battery is shredded and crushed to make most of the black powder fall off the current collector and promote the dissociation of the current collector material and the steel shell, thereby obtaining a first mixture consisting of thermal runaway black powder, flaky current collector and steel shell.

[0010] It should be noted that the present invention takes into account that due to the complex chemical reactions that occur during the thermal runaway process of lithium batteries, the electrolyte and binder are almost completely consumed, in addition to the generation of gases such as hydrogen, carbon dioxide, carbon monoxide, and hydrogen fluoride, and the positive electrode material is decomposed into magnetic ternary oxides and lithium oxide, namely nickel cobalt manganese oxide and lithium oxide, and these changes are conducive to the recovery of valuable components, wherein the magnetic ternary oxides and lithium oxide after the decomposition of the positive electrode material will form thermal runaway black powder together with the negative electrode material. In order to achieve the recovery of the valuable components such as the above-mentioned magnetic ternary oxides, lithium oxide, copper, aluminum and negative electrode graphite, the present invention is specifically implemented by the following steps.

[0011] The present invention first shreds the thermal runaway lithium-ion battery so as to miniaturize the thermal runaway lithium-ion battery. However, considering that part of the current collector is not completely separated from the positive and negative electrode materials in the shredded product, the present invention further crushes the shredded product to promote the thermal runaway black powder to fall off from the current collector and promote the dissociation of the current collector material from the steel shell.

[0012] In some preferred embodiments of the present invention, the thermal runaway lithium-ion battery is disassembled and sent to a uniaxial shredding device, so that the thermal runaway lithium-ion battery is shredded into particles with a diameter of less than 30 mm by the uniaxial shredding device.

[0013] In some preferred embodiments of the present invention, a vertical crushing device is used for crushing, so that the shredded products obtained after the shredding process are further crushed to a particle size of <10 mm by the vertical crushing device.

[0014] In some preferred embodiments of the present invention, the shredding process and the crushing process are both carried out under negative pressure, and the pressure of the negative pressure is 0.02MPa-0.05MPa to prevent dust such as black powder from escaping during the shredding process and the crushing process.

[0015] In some more preferred embodiments of the present invention, the present invention takes into account that in the material processed by the uniaxial shredding device, only part of the black powder falls off the current collector, and the other black powder, mainly the aluminum foil of the positive electrode, will adhere to the current collector due to the action of the binder, and the adhesion between the current collector and the black powder is not due to electrostatic adsorption, but is affected by the adhesive. Therefore, external force must be applied to make it possible to make the black powder fall off. Therefore, the present invention adopts a uniaxial shredding device and a vertical crushing device in combination to achieve a combined shredding process and a crushing process, so that the thermal runaway lithium-ion battery is first processed to a particle size of <30mm by a uniaxial shredding device, and then the material processed by the uniaxial shredding device is further impact-crushed by a vertical crushing device, so that the impact of the vertical crushing device can not only cause the black powder to fall off, but also reduce the size of the current collector to a certain extent.

[0016] Step 2, iron removal device treatment:

[0017] The first mixture is separated by an iron removal device to obtain a steel shell and a second mixture consisting of thermal runaway black powder and a sheet-like current collector.

[0018] It should be noted that the present invention takes into account the magnetic difference between the steel shell and the second mixture composed of thermal runaway black powder and flaky current collector in the crushed products obtained by the crushing process. Therefore, based on the factor of magnetic difference, the present invention preferably uses an iron removal device to separate the first mixture, thereby separating the steel shell from the first mixture through the iron removal device, and then obtaining the steel shell and the second mixture composed of thermal runaway black powder and flaky current collector respectively.

[0019] In order to improve the separation effect of the iron removal device on the steel shell in the first mixture, in some preferred embodiments of the present invention, when the iron removal device is used to separate the mixture, the magnetic field strength used is 1000Gs to ensure that the steel shell is separated without affecting the magnetic ternary oxide in the mixture.

[0020] Step 3, sucking the second mixture into a cyclone separation device under negative pressure for classification, and obtaining thermal runaway black powder and a sheet-like current collector respectively.

[0021] It should be noted that the present invention takes into account the large size difference between the thermal runaway black powder and the sheet-like current collector. Therefore, based on the size difference factor, the present invention preferably uses the airflow classification technology of the cyclone separation device to classify the second mixture, so as to obtain the thermal runaway black powder and the sheet-like current collector respectively.

[0022] Since the airflow classification technology of the cyclone separation device is a prior art, those skilled in the art should be aware of it, and thus the present invention will not be described in detail herein.

[0023] Step 4: evenly disperse the thermal runaway black powder in water to form a slurry; and perform wet magnetic separation on the slurry to obtain a magnetic ternary oxide and remaining slurry.

[0024] It should be noted that the present invention takes into account that in the obtained thermal runaway black powder, the positive electrode decomposition product ternary oxide has magnetism, while other components do not have magnetism. Therefore, based on the factor of magnetic difference, the present invention preferably adopts wet magnetic separation to separate the magnetic ternary oxide from other components.

[0025] At the same time, the present invention takes into account the presence of lithium carbonate in the thermal runaway black powder. In order to shorten the processing time and simplify the processing process, the present invention first places the thermal runaway black powder in water, so that all components of the thermal runaway black powder are dispersed in the water, so that the lithium carbonate therein is fully dissolved in the water to form a slurry. Then, the slurry in which the lithium carbonate is fully dissolved is subjected to wet magnetic separation to achieve the adsorption and separation of the magnetic ternary oxide by wet magnetic separation, and to achieve the separation of the magnetic ternary oxide from other remaining slurry components.

[0026] In some more preferred embodiments of the present invention, the thermal runaway black powder is uniformly dispersed in water by stirring, and the temperature is raised to 35°C to 45°C to form a slurry. In addition, the present invention takes into account factors such as the solubility of lithium oxide in the thermal runaway black powder after being converted into lithium carbonate. In another preferred embodiment of the present invention, when preparing the slurry, the concentration of the thermal runaway black powder in the slurry is 30g / L to 40g / L.

[0027] In some preferred embodiments of the present invention, the present invention takes into account that the obtained magnetic ternary oxide is weakly magnetic and difficult to separate using ordinary magnets, so the present invention uses a higher magnetic field strength to separate it from non-magnetic materials. In order to ensure that the magnetic ternary oxide can be completely adsorbed and separated by wet magnetic separation, in some more preferred embodiments of the present invention, the magnetic field strength used is 3000Gs to 4000Gs.

[0028] Step 5, post-processing of the remaining slurry:

[0029] The remaining slurry is separated into solid and liquid to obtain a lithium carbonate solution and negative electrode graphite; the lithium carbonate solution is evaporated and crystallized to obtain lithium carbonate crystals.

[0030] It should be noted that the present invention takes into account that the remaining components in the remaining slurry are lithium carbonate that has been dissolved in water and negative electrode graphite that is insoluble in water. Therefore, the present invention can separate the lithium carbonate and negative electrode graphite in the remaining slurry by solid-liquid separation. The separated liquid component is a lithium carbonate solution, and the obtained solid component is negative electrode graphite.

[0031] In order to obtain purer lithium carbonate, the present invention preferably uses evaporation crystallization to treat the lithium carbonate solution so as to recrystallize the lithium carbonate crystals. In order to ensure that pure lithium carbonate can be obtained, in some preferred embodiments of the present invention, the evaporation crystallization temperature used is 90°C to 100°C, so as to increase the evaporation rate of water at this temperature and accelerate the efficiency of lithium carbonate crystallization.

[0032] Step 6, color sorting:

[0033] The sheet-like current collector is subjected to color sorting treatment to obtain copper sheets and incompletely dissociated aluminum sheets.

[0034] It should be noted that the present invention takes into account that since the copper sheet in the sheet-like current collector is reddish brown and the incompletely dissociated aluminum sheet is light black, color sorting can be used to separate the copper sheet and the incompletely dissociated aluminum sheet based on the color difference between the two to obtain the copper sheet and the incompletely dissociated aluminum sheet respectively.

[0035] Step 7, post-treatment of incompletely dissociated aluminum flakes:

[0036] The incompletely dissociated aluminum flakes are ground and sieved to obtain positive electrode black powder and aluminum flakes respectively; the positive electrode black powder and the thermal runaway black powder are formed into a slurry together and then further processed.

[0037] It should be noted that the present invention takes into account that although most of the organic components of lithium-ion batteries, including electrolytes, separators and binders, have been decomposed during the thermal runaway process, a small amount of residual binder will still firmly adhere the black powder to the surface of the current collector. In the shredding and vertical crushing stages, most of the thermal runaway black powder has been separated from the current collector, but there will still be a small amount of undissociated, especially the positive electrode material with strong adhesion. Therefore, in order to avoid the loss of black powder, the residual black powder on the undissociated aluminum sheet after separation is recovered, the undissociated aluminum sheet is ground, and the dissociated black powder in the ground product is separated from the aluminum sheet by screening and grading.

[0038] In some preferred embodiments of the present invention, when the incompletely dissociated aluminum sheet is ground, a grinder is used for grinding, and the rotation speed of the grinder is 2000 rpm to 2500 rpm.

[0039] In some preferred embodiments of the present invention, during the screening, the sieve hole diameter of the screening device used is 0.125 mm, so that the positive electrode black powder with a particle size of <0.125 mm can pass through, while the aluminum flakes with a particle size greater than 0.125 mm are retained, thereby achieving the separation of the positive electrode black powder and the aluminum flakes.

[0040] In some preferred embodiments of the present invention, in order to improve the evaporation and crystallization efficiency of the lithium carbonate solution, the evaporation and crystallization temperature is 90° C. to 100° C., and the evaporation and crystallization are performed until constant weight is reached.

[0041] The second object of the present invention is to provide a device for recovering valuable components in a thermal runaway lithium-ion battery, and the device of the present invention is arranged based on the above-mentioned method for recovering valuable components in a thermal runaway lithium-ion battery. The device of the present invention includes a uniaxial shredding device, a vertical crushing device, an iron removal device, a cyclone separation device, a bag dust removal device, a slurry preparation device, a wet magnetic separation device, a slurry post-processing device, a color sorting device, an incompletely dissociated aluminum sheet post-processing device, and a negative pressure device.

[0042] In the present invention, the feed end of the uniaxial shredding device is used to add thermal runaway lithium-ion batteries to shred the added thermal runaway lithium-ion batteries, so that the thermal runaway lithium-ion batteries are shredded by the uniaxial shredding device until the particle size of the shredded products is less than 30 mm.

[0043] In the present invention, the feed end of the vertical crushing device is connected to the discharge end of the uniaxial shredding device to receive the shredded products after shredding from the uniaxial shredding device, and the received shredded products are crushed to a particle size of <10 mm to promote the thermal runaway black powder to fall off from the current collector and promote the dissociation of the current collector material and the steel shell.

[0044] In the present invention, the feed end of the iron removal device is connected to the discharge end of the vertical crushing device to receive the crushed product after the crushing process of the vertical crushing device, and perform preliminary separation on it, thereby realizing the separation of the steel shell and other components through the iron removal device based on the magnetic difference. In order to obtain the steel shell and the second mixture composed of thermal runaway black powder and flaky current collector respectively, the iron removal device is respectively provided with a first discharge port and a second discharge port, the first discharge port is used to output the separated steel shell, and the second discharge port is used to output the second mixture composed of thermal runaway black powder and flaky current collector.

[0045] In the present invention, the feed end of the cyclone separation device is connected to the second discharge port to receive the second mixture and classify the second mixture based on the airflow classification technology, thereby achieving separation of the second mixture. In order to obtain thermal runaway black powder and sheet-like current collectors respectively, the cyclone separation device is respectively provided with a third discharge port and a fourth discharge port, the third discharge port is used to output the separated thermal runaway black powder, and the fourth discharge port is used to output the sheet-like current collector.

[0046] In the present invention, the feed end of the bag dust removal device is connected to the third discharge port to avoid dust diffusion or black powder loss that may be caused by the thermal runaway black powder during the classification process of the cyclone separation device, thereby achieving efficient collection of the thermal runaway black powder output from the third discharge port, so as to improve the subsequent recovery efficiency of the valuable components in the thermal runaway black powder.

[0047] In the present invention, the feed end of the slurry preparation device is respectively connected to the water source and the third discharge port to prepare slurry from the received water and thermal runaway black powder.

[0048] In the present invention, the feed end of the wet magnetic separation device is connected to the discharge end of the slurry preparation device to receive the slurry from the slurry preparation device and perform wet magnetic separation on it, thereby realizing the separation of the magnetic ternary oxide and the remaining slurry. In order to obtain the magnetic ternary oxide and the remaining slurry respectively, the wet magnetic separation device is respectively provided with a fifth discharge port and a sixth discharge port, the fifth discharge port is used to output the separated magnetic ternary oxide, and the sixth discharge port is used to output the remaining slurry.

[0049] In the present invention, the slurry post-processing device comprises a filtration unit and an evaporation unit connected in sequence, and the feed end of the filtration unit is connected to the sixth discharge port, so as to separate the residual slurry into solid and liquid through the filtration unit, thereby obtaining a lithium carbonate solution and negative electrode graphite. The lithium carbonate solution enters the evaporation unit, and is evaporated and crystallized to obtain lithium carbonate crystals, so that the valuable components in the residual slurry can be effectively recovered through the slurry post-processing device.

[0050] In the present invention, the feed end of the color sorting device is connected to the fourth discharge port to receive the sheet-like current collector output from the fourth discharge port and perform color sorting on it to achieve separation of copper sheets and incompletely dissociated aluminum sheets. In order to separate the copper sheets and incompletely dissociated aluminum sheets, the color sorting device is respectively provided with a seventh discharge port and an eighth discharge port, the seventh discharge port is used to output the separated copper sheets, and the eighth discharge port is used to output the incompletely dissociated aluminum sheets.

[0051] In the present invention, the post-processing device for the incompletely dissociated aluminum flakes comprises a grinding unit and a screening unit connected in sequence, wherein the grinding unit is connected to the eighth discharge port, so that the incompletely dissociated aluminum flakes are ground by the grinding unit, and the grinding product enters the screening unit for screening, wherein the sieve hole diameter of the screening unit is 0.125 mm, so that the positive electrode black powder with a particle size of <0.125 mm passes through, while the aluminum flakes with a particle size of >0.125 mm are retained, so as to achieve the separation of the positive electrode black powder and the aluminum flakes. In order to obtain the positive electrode black powder and the aluminum flakes respectively, the screening unit is provided with a ninth discharge port and a tenth discharge port, respectively, the ninth discharge port is used to output the separated aluminum flakes, and the tenth discharge port is used to output the positive electrode black powder.

[0052] In the present invention, the tenth discharge port is connected to the feed end of the slurry preparation device to form the positive electrode black powder and the thermal runaway black powder into slurry and then continue to process them to further improve the recovery efficiency of the valuable components in the positive electrode black powder.

[0053] In the present invention, the negative pressure device is arranged between the second discharge port of the iron removal device and the feed end of the cyclone separation device to provide a negative pressure environment for the processing process of the single-axis shredding device, the vertical crushing device and the iron removal device.

[0054] Considering that in some preferred embodiments of the present invention, the single-shaft shredding device is the SR600 single-shaft shredding device of Shouyu Machinery.

[0055] In some preferred embodiments of the present invention, the vertical crushing device is a vertical crushing device. The vertical crushing device used in the present invention is provided with four layers of blade assemblies, and each layer of blade assemblies is composed of three blades arranged at an interval of 120°. A screen with a mesh of 10 mm is arranged at the bottom of the crusher, so that the thermal runaway lithium-ion battery is broken to <10 mm through the synergistic effect of the four layers of blade assemblies, and most of the thermal runaway black powder is promoted to fall off from the current collector, thereby facilitating the separation of the two through airflow classification.

[0056] In some preferred embodiments of the present invention, the slurry preparation device includes a preparation cavity, in which a heating unit and a stirring unit are arranged; the feed end of the preparation cavity is connected to a water source and the third discharge port respectively, so as to receive water and thermal runaway black powder. The heating unit and the stirring unit are used to uniformly disperse the thermal runaway black powder in water under stirring, and heat it to 35°C to 45°C to form slurry.

[0057] In some preferred embodiments of the present invention, in order to prevent the escape of black powder during shredding, crushing and iron removal, the present invention connects the single-axis shredding device, vertical crushing device and iron removal device used in the disassembly, crushing and screening processes in sequence through pipelines. The cyclone separation device driven by the fan will generate negative pressure at the feed inlet, so that the single-axis shredding device, the vertical crushing device and the iron removal device are all operated under a negative pressure of 0.02 to 0.05 MPa during the treatment process, thereby preventing dust (black powder) from escaping. At the same time, during the treatment process, the vertical crushing device has its vertical shaft rotating at high speed, which will drive the rotation of each layer of blades and generate an upward airflow, which is not conducive to the falling of materials. The present invention adds negative pressure to the connected shredding, impact crushing and iron removal devices, which can also resist the upward airflow to ensure that the material can fall smoothly. The structural schematic diagram of the single-axis shredding device, the vertical crushing device, the iron removal device and the cyclone separation device connected in sequence is shown in the figure. Figure 1 shown.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] Based on the physical and chemical properties of thermal runaway lithium-ion batteries, the present invention first shreds the thermal runaway lithium-ion batteries to facilitate miniaturization of the thermal runaway lithium-ion batteries. However, considering that some of the current collectors in the shredded products are not completely separated from the positive and negative electrode materials, the present invention further crushes the shredded products to promote the thermal runaway black powder to fall off from the current collectors and to promote the dissociation of the current collector materials from the steel shell. An iron removal device is then used to separate the first mixture consisting of thermal runaway black powder, flaky current collectors and steel shells, thereby separating the steel shell from the first mixture through the iron removal device, and then obtaining the steel shell and the second mixture consisting of thermal runaway black powder and flaky current collectors. Subsequently, based on the size difference, the airflow classification technology of the cyclone separation device is used to classify the second mixture, so that the thermal runaway black powder and the flaky current collector can be obtained respectively. Then, the magnetic ternary oxide is separated from other components by wet magnetic separation; since lithium carbonate is still present in the thermal runaway black powder, in order to shorten the processing time and simplify the processing process, the present invention first places the thermal runaway black powder in water, so that all components of the thermal runaway black powder are dispersed in the water, so that the lithium carbonate therein is fully dissolved in the water to form a slurry, and then the slurry in which the lithium carbonate is fully dissolved is subjected to wet magnetic separation to achieve the adsorption and separation of the magnetic ternary oxide by wet magnetic separation, and to achieve the separation of the magnetic ternary oxide from other remaining slurry components. The present invention takes into account that since the remaining components in the remaining slurry are lithium carbonate that has been dissolved in water, and negative electrode graphite that is insoluble in water, the separation of lithium carbonate and negative electrode graphite in the remaining slurry is achieved by solid-liquid separation, and the separated liquid component is a lithium carbonate solution, and the solid component obtained is negative electrode graphite. The present invention uses evaporation crystallization to treat the lithium carbonate solution so that it recrystallizes to obtain lithium carbonate crystals. Since the copper sheet in the sheet current collector is reddish brown and the incompletely dissociated aluminum sheet is light black, the color sorting process can be used to separate the copper sheet and the incompletely dissociated aluminum sheet based on the color difference between the two, and obtain the copper sheet and the incompletely dissociated aluminum sheet respectively. The present invention takes into account that although most of the organic components including electrolyte, diaphragm and binder in the thermal runaway process of lithium-ion batteries have been decomposed, a small amount of residual binder will still firmly adhere the black powder to the surface of the current collector. In the shredding and vertical crushing links, most of the thermal runaway black powder has been separated from the current collector, but there will still be a small amount of undissociated, especially the positive electrode material with strong adhesion. Therefore, in order to avoid the loss of black powder, the residual black powder on the undissociated aluminum sheet after separation is recovered, the undissociated aluminum sheet is ground, and the dissociated black powder in the ground product is separated from the aluminum sheet by screening and grading.

[0060] The present invention obtains valuable components of high-purity copper, aluminum, ternary oxides and negative electrode graphite through physical methods including crushing, screening, magnetic separation, dry separation, evaporation crystallization, color separation, grinding, classification, etc. The recovery method of the present invention has a simple treatment process, low energy consumption, can effectively avoid secondary pollution during the recovery process, is environmentally friendly and has a high recovery rate, and is conducive to promotion and large-scale use. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a schematic structural diagram of the recovery device of the present invention. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0063] Example 1

[0064] This embodiment provides a method for recovering valuable components in a thermal runaway lithium-ion battery, comprising the following steps:

[0065] Step 1, shredding and crushing:

[0066] 1.1) Under a negative pressure of 0.02 MPa to 0.05 MPa, the collected 18650-type thermal runaway lithium-ion batteries with a diameter of 18 mm and a height of 65 mm and a positive electrode material of 811-type ternary material were disassembled and shredded to a particle size of <30 mm to obtain shredded products.

[0067] 1.2) The shredded product is crushed to a particle size of less than 10 mm to obtain a first mixture consisting of thermal runaway black powder, a sheet-like current collector and a steel shell.

[0068] Step 2, iron removal device treatment:

[0069] The first mixture obtained in 1.2) is separated by an iron removal device. During separation, the magnetic field strength of the iron removal device is controlled to be 1000 Gs to separate the steel shell from the first mixture, thereby obtaining the steel shell and the second mixture consisting of thermal runaway black powder and flaky current collector.

[0070] Step 3, classification treatment of cyclone separation device:

[0071] The second mixture obtained in step 2 is sucked into the cyclone separation device through negative pressure. The second mixture can be graded under the airflow classification technology due to the difference in quality to obtain thermal runaway black powder and sheet-like current collector respectively.

[0072] Step 4, pulping and wet magnetic separation:

[0073] 4.1) Under stirring, the thermal runaway black powder obtained in step 3 is evenly dispersed in water, and the temperature is raised to 40° C. and stirring is continued to form a slurry with a thermal runaway black powder concentration of 35 g / L.

[0074] 4.2) The ore pulp obtained in 4.1) is subjected to wet magnetic separation, and the magnetic field intensity of the wet magnetic separation is 3000 Gs to obtain magnetic ternary oxide and residual ore pulp.

[0075] Step 5, post-processing of the remaining slurry:

[0076] 5.1) Separate the remaining slurry from 4.2) into solid and liquid to obtain lithium carbonate solution and negative electrode graphite.

[0077] 5.2) The lithium carbonate solution obtained in 5.1) is evaporated and crystallized at 90° C. to constant weight to obtain lithium carbonate crystals.

[0078] Step 6, color sorting:

[0079] The sheet-like current collector is subjected to color sorting treatment to obtain reddish brown copper sheets and light black incompletely dissociated aluminum sheets.

[0080] Step 7, post-treatment of incompletely dissociated aluminum flakes:

[0081] 7.1) Grinding the incompletely dissociated aluminum flakes obtained in step 6 to obtain a ground product.

[0082] 7.2) The ground product of 7.1) is sieved through a sieving device with a sieve hole diameter of 0.125 mm, so that the positive electrode black powder with a particle size of <0.125 mm passes through, while the aluminum flakes with a particle size greater than 0.125 mm are retained, thereby achieving separation of the positive electrode black powder and the aluminum flakes.

[0083] 7.3) The positive electrode black powder obtained in 7.2) is returned to step 4 and formed into a slurry together with the thermal runaway black powder and then further processed.

[0084] After being processed by this embodiment, tests show that the copper and aluminum content in the magnetic ternary oxide obtained by this embodiment is less than 5%; the recovery rate of nickel, cobalt and manganese elements is 99.5%; the recovery rate of lithium element is 90.14%, and the purity of lithium carbonate is 95.9%; the copper recovery rate is 98.5%, and the purity is 95.2%; the aluminum recovery rate is 94.6%, and the purity is 97.4%.

[0085] Example 2

[0086] This embodiment provides a method for recovering valuable components in a thermal runaway lithium-ion battery, comprising the following steps:

[0087] Step 1, shredding and crushing:

[0088] 1.1) Under a negative pressure of 0.02 MPa to 0.05 MPa, the collected 18650-type thermal runaway lithium-ion batteries with a diameter of 18 mm and a height of 65 mm and a positive electrode material of 811-type ternary material were disassembled and shredded to a particle size of <30 mm to obtain shredded products.

[0089] 1.2) The shredded product is crushed to a particle size of less than 10 mm to obtain a first mixture consisting of thermal runaway black powder, a sheet-like current collector and a steel shell.

[0090] Step 2, iron removal device treatment:

[0091] The first mixture obtained in 1.2) is separated by an iron removal device. During separation, the magnetic field strength of the iron removal device is controlled to be 1000 Gs to separate the steel shell from the first mixture, thereby obtaining the steel shell and the second mixture consisting of thermal runaway black powder and flaky current collector.

[0092] Step 3, classification treatment of cyclone separation device:

[0093] The second mixture obtained in step 2 is sucked into the cyclone separation device through negative pressure. The second mixture can be graded under the airflow classification technology due to the difference in quality to obtain thermal runaway black powder and sheet-like current collector respectively.

[0094] Step 4, pulping and wet magnetic separation:

[0095] 4.1) The thermal runaway black powder obtained in step 3 is evenly dispersed in water under stirring, and the temperature is raised to 35° C. and stirring is continued to form a slurry with a thermal runaway black powder concentration of 40 g / L.

[0096] 4.2) The ore pulp obtained in 4.1) is subjected to wet magnetic separation, and the magnetic field intensity of the wet magnetic separation is 3500 Gs to obtain magnetic ternary oxide and residual ore pulp.

[0097] Step 5, post-processing of the remaining slurry:

[0098] 5.1) Separate the remaining slurry from 4.2) into solid and liquid to obtain lithium carbonate solution and negative electrode graphite.

[0099] 5.2) The lithium carbonate solution obtained in 5.1) was evaporated and crystallized at 95° C. to constant weight to obtain lithium carbonate crystals.

[0100] Step 6, color sorting:

[0101] The sheet-like current collector is subjected to color sorting treatment to obtain copper sheets and incompletely dissociated aluminum sheets.

[0102] Step 7, post-treatment of incompletely dissociated aluminum flakes:

[0103] 7.1) Grinding the incompletely dissociated aluminum flakes obtained in step 6 to obtain a ground product.

[0104] 7.2) The ground product of 7.1) is sieved through a sieving device with a sieve hole diameter of 0.125 mm, so that the positive electrode black powder with a particle size of <0.125 mm passes through, while the aluminum flakes with a particle size of >0.125 mm are retained, thereby achieving separation of the positive electrode black powder and the aluminum flakes.

[0105] 7.3) The positive electrode black powder obtained in 7.2) is returned to step 4 and formed into a slurry together with the thermal runaway black powder and then further processed.

[0106] Example 3

[0107] This embodiment provides a method for recovering valuable components in a thermal runaway lithium-ion battery, comprising the following steps:

[0108] Step 1, shredding and crushing:

[0109] 1.1) Under a negative pressure of 0.02 MPa to 0.05 MPa, the collected 18650-type thermal runaway lithium-ion batteries with a diameter of 18 mm and a height of 65 mm and a positive electrode material of 811-type ternary material were disassembled and shredded to a particle size of <30 mm to obtain shredded products.

[0110] 1.2) The shredded product is crushed to a particle size of less than 10 mm to obtain a first mixture consisting of thermal runaway black powder, a sheet-like current collector and a steel shell.

[0111] Step 2, iron removal device treatment:

[0112] The first mixture obtained in 1.2) is separated by an iron removal device. During separation, the magnetic field strength of the iron removal device is controlled to be 1000 Gs to separate the steel shell from the first mixture, thereby obtaining the steel shell and the second mixture consisting of thermal runaway black powder and flaky current collector.

[0113] Step 3, classification treatment of cyclone separation device:

[0114] The second mixture obtained in step 2 is sucked into the cyclone separation device through negative pressure. The second mixture can be graded under the airflow classification technology due to the difference in quality to obtain thermal runaway black powder and sheet-like current collector respectively.

[0115] Step 4, pulping and wet magnetic separation:

[0116] 4.1) Under stirring, the thermal runaway black powder obtained in step 3 is evenly dispersed in water, and the temperature is raised to 45° C. and stirring is continued to form a slurry with a thermal runaway black powder concentration of 45 g / L.

[0117] 4.2) The ore pulp obtained in 4.1) is subjected to wet magnetic separation, and the magnetic field intensity of the wet magnetic separation is 4000 Gs to obtain magnetic ternary oxide and residual ore pulp.

[0118] Step 5, post-processing of the remaining slurry:

[0119] 5.1) Separate the remaining slurry from 4.2) into solid and liquid to obtain lithium carbonate solution and negative electrode graphite.

[0120] 5.2) The lithium carbonate solution obtained in 5.1) is evaporated and crystallized at 90° C. to constant weight to obtain lithium carbonate crystals.

[0121] Step 6, color sorting:

[0122] The sheet-like current collector is subjected to color sorting treatment to obtain copper sheets and incompletely dissociated aluminum sheets.

[0123] Step 7, post-treatment of incompletely dissociated aluminum flakes:

[0124] 7.1) Grinding the incompletely dissociated aluminum flakes obtained in step 6 to obtain a ground product.

[0125] 7.2) The ground product of 7.1) is sieved through a sieving device with a sieve hole diameter of 0.125 mm, so that the positive electrode black powder with a particle size of <0.125 mm passes through, while the aluminum flakes with a particle size greater than 0.125 mm are retained, thereby achieving separation of the positive electrode black powder and the aluminum flakes.

[0126] 7.3) The positive electrode black powder obtained in 7.2) is returned to step 4 and formed into a slurry together with the thermal runaway black powder and then further processed.

[0127] And the test shows that the recovery effect of Example 2 and Example 3 is similar to that of Example 1, and the copper and aluminum content in the obtained magnetic ternary oxide is less than 3.5%; the recovery rate of nickel, cobalt and manganese elements is 99.2% to 99.5%; the recovery rate of lithium element is 89.2% to 90.8%; the copper recovery rate is 97.5% to 98.1%; and the aluminum recovery rate is 91.7% to 93.0%.

[0128] Example 4

[0129] See also Figure 1 The present embodiment provides a device for recovering valuable components in a thermal runaway lithium-ion battery, comprising a single-axis shredding device 1, a vertical crushing device 2, an iron removal device 3, a cyclone separation device 4, a bag dust removal device 5, a slurry preparation device 6, a wet magnetic separation device 7, a slurry post-processing device 8, a color sorting device 9, an incompletely dissociated aluminum sheet post-processing device 10 and a negative pressure device 11.

[0130] In this embodiment, the uniaxial shredder used is the SR600 uniaxial shredder purchased from Shouyu Machinery. After the thermal runaway lithium-ion battery is disassembled and added to the feed end of the uniaxial shredder 1, the thermal runaway lithium-ion battery entering the uniaxial shredder 1 is shredded by the uniaxial shredder 1 until the particle size of the shredded product is <30 mm.

[0131] In this embodiment, the vertical crushing device 2 used is a vertical impact crusher, and the feed end of the vertical impact crusher is connected to the discharge end of the uniaxial shredding device 1, so that the shredded products after the shredding process of the uniaxial shredding device 1 can enter the vertical impact crusher for shredding process, so as to crush the thermal runaway lithium-ion battery to <10mm, and at the same time promote most of the thermal runaway black powder to fall off from the current collector, thereby helping to achieve the separation of the current collector material and the steel shell through airflow classification. Among them, it should be noted that the structure and working principle of the vertical impact crusher used in the present invention are both prior art in the field, and those skilled in the art should know, so the present invention will not be repeated here.

[0132] In this embodiment, the feed end of the iron removal device 3 is connected to the discharge end of the vertical crushing device 2 to receive the crushed product after the crushing process of the vertical crushing device 2, and perform preliminary separation on it, thereby realizing the separation of the steel shell and other components based on the magnetic difference through the iron removal device 3. In order to obtain the steel shell and the second mixture composed of thermal runaway black powder and flaky current collector respectively, the iron removal device 3 is respectively provided with a first discharge port 301 and a second discharge port 302, the first discharge port 301 is used to output the separated steel shell, and the second discharge port 302 is used to output the second mixture composed of thermal runaway black powder and flaky current collector.

[0133] In this embodiment, the feed end of the cyclone separation device 4 is connected to the second discharge port 302 to receive the second mixture and classify the second mixture based on the airflow classification technology, thereby achieving separation of the second mixture. In order to obtain the thermal runaway black powder and the sheet-like current collector respectively, the cyclone separation device 4 is respectively provided with a third discharge port 401 and a fourth discharge port 402, the third discharge port 401 is used to output the separated thermal runaway black powder, and the fourth discharge port 402 is used to output the sheet-like current collector.

[0134] In this embodiment, the feed end of the bag dust removal device 5 is connected to the third discharge port 401 to avoid dust diffusion or black powder loss that may be caused by the thermal runaway black powder during the grading process of the cyclone separation device 4, thereby achieving efficient collection of the thermal runaway black powder output from the third discharge port 401, so as to improve the subsequent recovery efficiency of the valuable components in the thermal runaway black powder.

[0135] In this embodiment, the slurry preparation device 6 includes a preparation cavity, in which a heating unit and a stirring unit are arranged; the feed end of the preparation cavity is connected to the water source and the third discharge port 401 respectively, so as to receive the water and the thermal runaway black powder. The heating unit and the stirring unit are used to uniformly disperse the thermal runaway black powder in the water under stirring, and heat it to 35°C to 45°C to form slurry.

[0136] In this embodiment, the feed end of the wet magnetic separation device 7 is connected to the discharge end of the slurry preparation device 6 to receive the slurry from the slurry preparation device 6 and perform wet magnetic separation on it, thereby realizing the separation of the magnetic ternary oxide and the remaining slurry. In order to obtain the magnetic ternary oxide and the remaining slurry respectively, the wet magnetic separation device 7 is respectively provided with a fifth discharge port 701 and a sixth discharge port 702, the fifth discharge port 701 is used to output the separated magnetic ternary oxide, and the sixth discharge port 702 is used to output the remaining slurry.

[0137] In this embodiment, the slurry post-processing device 8 includes a filter unit 801 and an evaporation unit 802 connected in sequence, and the feed end of the filter unit 801 is connected to the sixth discharge port 702, so that the remaining slurry is separated into solid and liquid by the filter unit 801, thereby obtaining a lithium carbonate solution and negative electrode graphite. The lithium carbonate solution enters the evaporation unit 802, and is evaporated and crystallized to obtain lithium carbonate crystals, so that the valuable components in the remaining slurry are effectively recovered by the slurry post-processing device 8.

[0138] In this embodiment, the feed end of the color sorting device 9 is connected to the fourth discharge port 402 to receive the sheet-like current collector output from the fourth discharge port 402 and perform color sorting on it to achieve separation of copper sheets and incompletely dissociated aluminum sheets. In order to separate the copper sheets and incompletely dissociated aluminum sheets, the color sorting device 9 is respectively provided with a seventh discharge port 901 and an eighth discharge port 902, wherein the seventh discharge port 901 is used to output the separated copper sheets, and the eighth discharge port 902 is used to output the incompletely dissociated aluminum sheets.

[0139] In this embodiment, the incompletely dissociated aluminum flake post-processing device 10 includes a grinding unit 101 and a screening unit 102 connected in sequence, and the grinding unit 101 is connected to the eighth discharge port 902, so that the incompletely dissociated aluminum flakes are ground by the grinding unit 101, and the grinding product enters the screening unit 102 for screening, wherein the sieve hole aperture of the screening unit 102 is 0.125mm, so that the positive electrode black powder with a particle size <0.125mm passes through, and the aluminum flakes with a particle size greater than 0.125mm are retained, thereby realizing the separation of the positive electrode black powder and the aluminum flakes. In order to obtain the positive electrode black powder and the aluminum flakes respectively, the screening unit 102 is respectively provided with a ninth discharge port 103 and a tenth discharge port 104, wherein the ninth discharge port 103 is used to output the separated aluminum flakes, and the tenth discharge port 104 is used to output the positive electrode black powder.

[0140] In this embodiment, the tenth discharge port 104 is connected to the feed end of the slurry preparation device 6 to form the positive electrode black powder and the thermal runaway black powder into slurry and then continue to process them to further improve the recovery efficiency of the valuable components in the positive electrode black powder.

[0141] In this embodiment, the negative pressure device 11 is arranged between the second discharge port 302 of the iron removal device 3 and the feed end of the cyclone separation device 4 to provide a negative pressure environment for the processing process of the single-axis tearing device 1, the vertical crushing device 2 and the iron removal device 3.

[0142] In this embodiment, in order to prevent the black powder from escaping during the shredding, crushing and iron removal processes, the present invention connects the single-axis shredding device, vertical crushing device and iron removal device used in the disassembly, crushing and screening processes in sequence through pipelines. The cyclone separation device driven by the fan will generate negative pressure at the feed inlet, so that the single-axis shredding device, the vertical crushing device and the iron removal device are all operated under a negative pressure of 0.02MPa to 0.05MPa during the treatment process, thereby preventing dust, that is, black powder from escaping. At the same time, during the treatment process, the vertical crushing device has its vertical shaft rotating at high speed, which will drive the blades of each layer to rotate and generate an upward airflow, which is not conducive to the falling of the material. The present invention adds negative pressure to the connected shredding, impact crushing and iron removal devices, which can also resist the upward airflow to ensure that the material can fall smoothly. The structural schematic diagram of the single-axis shredding device, the vertical crushing device, the iron removal device and the cyclone separation device connected in sequence is shown in the figure. Figure 1 shown.

[0143] Obviously, the above embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A method for recovering valuable components in a thermal runaway lithium-ion battery, characterized in that: The following steps are involved: Under negative pressure, the thermal runaway lithium-ion battery is shredded and crushed to make most of the black powder fall off the current collector and promote the dissociation of the current collector material and the steel shell, thereby obtaining a first mixture consisting of thermal runaway black powder, flaky current collector and steel shell; The first mixture is separated by an iron removal device to obtain a steel shell and a second mixture consisting of thermal runaway black powder and a sheet-like current collector; The second mixture is sucked into a cyclone separation device under negative pressure for classification to obtain thermal runaway black powder and a sheet-like current collector respectively; The thermal runaway black powder is uniformly dispersed in water to form a slurry; the slurry is subjected to wet magnetic separation to obtain a magnetic ternary oxide and a residual slurry; Separating the remaining slurry into solid and liquid to obtain a lithium carbonate solution and negative electrode graphite; evaporating and crystallizing the lithium carbonate solution to obtain lithium carbonate crystals; The sheet-like current collector is subjected to color sorting treatment to obtain copper sheets and incompletely dissociated aluminum sheets respectively; The incompletely dissociated aluminum flakes are ground and then sieved to obtain positive electrode black powder and aluminum flakes respectively; the positive electrode black powder and the thermal runaway black powder are formed into a slurry together and then further processed.

2. The recycling method according to claim 1, characterized in that: The shredding process is performed until the particle size of the shredded product is less than 30 mm.

3. The recycling method according to claim 1, characterized in that: The crushing process is performed until the particle size of the first mixture is less than 10 mm.

4. The recycling method according to claim 1, characterized in that: The negative pressure is 0.02MPa to 0.05MPa.

5. The recycling method according to claim 1, characterized in that: The particle size of the thermal runaway black powder is less than 0.125 mm.

6. The recycling method according to claim 1, characterized in that: When the iron removal device separates the mixture, the magnetic field strength used is 1000 Gs.

7. The recycling method according to claim 1, characterized in that: The thermal runaway black powder is uniformly dispersed in water by stirring, and the temperature is raised to 35° C. to 45° C. to form a slurry; And the concentration of the slurry is 30g / L to 40g / L.

8. The recycling method according to claim 1, characterized in that: The magnetic field strength used in the wet magnetic separation method is 3000Gs to 4000Gs.

9. The recycling method according to claim 1, characterized in that: When grinding the incompletely dissociated aluminum sheet, a grinder is used for grinding, and the rotation speed of the grinder is 2000 rpm to 2500 rpm; During the screening, the sieve hole diameter of the screening device used is 0.125 mm, so that the positive electrode black powder with a particle size of less than 0.125 mm passes through, while the aluminum flakes with a particle size of more than 0.125 mm are retained, so as to separate the positive electrode black powder from the aluminum flakes.

10. A recycling device based on the recycling method according to any one of claims 1 to 9, characterized in that: include: A single-axis shredding device (1), the feed end of which is used to add thermal runaway lithium-ion batteries, so as to shred the added thermal runaway lithium-ion batteries; A vertical crushing device (2), the feeding end of which is connected to the discharging end of the single-shaft shredding device (1), so as to receive the shredded product after the shredding process from the single-shaft shredding device (1) and perform shredding process on it; An iron removal device (3), whose feeding end is connected to the discharging end of the vertical crushing device (2) to receive the crushed product after the crushing process of the vertical crushing device (2) and perform preliminary separation on it; the iron removal device (3) is respectively provided with a first discharge port (301) and a second discharge port (302), the first discharge port (301) is used to output the separated steel shell, and the second discharge port (302) is used to output the second mixture composed of thermal runaway black powder and flaky current collector; A cyclone separation device (4), wherein the feed end is connected to the second discharge port (302) to receive the second mixture and classify the second mixture based on the airflow classification technology; the cyclone separation device (4) is respectively provided with a third discharge port (401) and a fourth discharge port (402), wherein the third discharge port (401) is used to output the separated thermal runaway black powder, and the fourth discharge port (402) is used to output the sheet-shaped current collector; A bag dust removal device (5), the feeding end of which is in communication with the third discharge port (401) so as to collect thermal runaway black powder outputted from the third discharge port (401); A slurry preparation device (6), the feed end of which is respectively connected to a water source and an output end of the bag dust removal device (5) to prepare slurry from the received water and thermal runaway black powder; A wet magnetic separation device (7), the feed end of which is in communication with the discharge end of the slurry preparation device (6) so as to receive the slurry from the slurry preparation device (6) and perform wet magnetic separation on it; the wet magnetic separation device (7) is respectively provided with a fifth discharge port (701) and a sixth discharge port (702), the fifth discharge port (701) being used to output the separated magnetic ternary oxide, and the sixth discharge port (702) being used to output the remaining slurry; A slurry post-processing device (8), comprising a filtering unit (801) and an evaporation unit (802) connected in sequence, wherein a feed end of the filtering unit (801) is connected to the sixth discharge port (702); A color sorting device (9), wherein the feed end is connected to the fourth discharge port (402) to receive the sheet-shaped current collector output from the fourth discharge port (402) and perform color sorting on it; the color sorting device (9) is respectively provided with a seventh discharge port (901) and an eighth discharge port (902), wherein the seventh discharge port (901) is used to output the separated copper sheet, and the eighth discharge port (902) is used to output the incompletely dissociated aluminum sheet; The incompletely dissociated aluminum flake post-processing device (10) comprises a grinding unit (101) and a screening unit (102) connected in sequence, wherein the grinding unit (101) is connected to the eighth discharge port (902); the screening unit (102) is respectively provided with a ninth discharge port (103) and a tenth discharge port (104), wherein the ninth discharge port (103) is used to output the separated aluminum flakes, and the tenth discharge port (104) is used to output the positive electrode black powder; and the tenth discharge port (104) is connected to the feed end of the slurry preparation device (6); A negative pressure device (11) is arranged between the second discharge port (302) of the iron removal device (3) and the feed end of the cyclone separation device (4) to provide a negative pressure environment for the processing process of the single-axis shredding device (1), the vertical crushing device (2) and the iron removal device (3).

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