Lithium battery recycling equipment and method

Abstract

The invention discloses lithium battery recovery equipment and method. The lithium battery recovery equipment comprises low-temperature equipment, microwave pyrolysis equipment and electrode material regeneration equipment, the low-temperature equipment is used for separating a current collector from a waste battery material; the microwave pyrolysis equipment is used for separating a waste electrode active material from an adhesive. According to the invention, low-temperature equipment utilizes a low-temperature embrittlement principle, so that the active material layer adhered to the current collector is easier to peel off; the recycling purity and efficiency of the current collector are greatly improved, and the current collector can be directly recycled as high-value metal. The microwave pyrolysis equipment utilizes microwaves to preferentially heat polar molecules and conductive materials. The organic binder and the residual electrolyte can be efficiently decomposed and removed, and meanwhile, the structure of the waste electrode active material is relatively protected; lithium ions lost in the circulation process are supplemented through electrode material regeneration equipment, the structural defect caused by lithium deficiency is repaired, and the electrochemical performance of the lithium ion battery is recovered.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium batteries, and in particular relates to a lithium battery recycling device and method. Background Art

[0002] Lithium batteries are primarily composed of a casing, a positive electrode, a negative electrode, an electrolyte, and a separator. Effectively separating the components of used lithium batteries and maximizing their resource utilization can help reduce battery costs.

[0003] In related technologies, metals are recovered through high-temperature reduction. Specifically, reducing agents (coke, coal) are used to reduce metal oxides into metal alloys (such as Co-Ni-Cu-Fe alloys) or compounds. Lithium usually exists in the form of slag (lithium silicate, lithium aluminate) and requires subsequent wet extraction. However, the high-temperature process consumes a lot of energy and the metal recovery rate is relatively low.

[0004] Related technologies also regenerate waste electrode materials through repair to improve their electrochemical properties so that they can be directly used in the manufacture of new batteries; however, the performance of the regenerated motor materials is relatively poor. Summary of the Invention

[0005] An object of the present invention is to provide a lithium battery recycling device to solve at least one aspect of the problems and defects raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides a lithium battery recycling device, comprising a low-temperature device, a microwave pyrolysis device and an electrode material regeneration device; The low-temperature equipment is used to separate the current collector and waste battery materials; The microwave pyrolysis equipment is used for separating waste electrode active materials and adhesives.

[0007] According to one technical solution of the present invention, at least the following beneficial effects are achieved: The low-temperature equipment of the present invention utilizes the principle of low-temperature embrittlement to make it easier to peel off the active material layer (including the binder) adhered to the current collector; it greatly improves the recovery purity and efficiency of the current collector, and can be directly recovered as high-value metal.

[0008] The low-temperature process is relatively mild and causes less damage to the crystal structure of waste electrode active materials, thus reducing the difficulty of regenerating waste electrode active materials.

[0009] Microwave pyrolysis equipment uses microwaves to preferentially heat polar molecules and conductive materials. This facilitates the efficient decomposition and removal of organic binders and residual electrolytes, while relatively preserving the structure of the spent electrode active materials. At the same time, it promotes the rapid decomposition of the binder, and further promotes the rapid separation of waste electrode active materials and the binder.

[0010] The present invention also replenishes lithium ions lost during the circulation process through electrode material regeneration equipment, repairs structural defects caused by lithium deficiency, and restores its electrochemical performance.

[0011] According to some embodiments of the present invention, a liquid nitrogen chamber is provided in the cryogenic equipment.

[0012] According to some embodiments of the present invention, a crushing device is further provided in the cryogenic equipment.

[0013] According to some embodiments of the present invention, a tail gas recovery device is provided in the microwave pyrolysis equipment.

[0014] According to some embodiments of the present invention, the electrode material regeneration device includes a high-pressure reactor and a microwave sintering furnace.

[0015] A second aspect of the present invention further provides a lithium battery recycling method, comprising the following steps: collecting waste battery materials and current collectors after low-temperature treatment of waste electrode sheets; collecting waste electrode active materials after microwave pyrolysis of the waste battery materials; The spent electrode active material is regenerated.

[0016] According to one of the technical solutions of the present invention, at least the following beneficial effects are achieved: The method of the present invention utilizes the principle of low-temperature embrittlement to make the active material layer (including the binder) adhered to the current collector easier to peel off; it greatly improves the recovery purity and efficiency of the current collector and can be directly recovered as high-value metal.

[0017] The low-temperature process is relatively mild and causes less damage to the crystal structure of waste electrode active materials, thus reducing the difficulty of regenerating waste electrode active materials.

[0018] During microwave pyrolysis, microwaves are used to preferentially heat polar molecules and conductive materials. This facilitates the efficient decomposition and removal of organic binders and residual electrolytes, while relatively preserving the structure of the spent electrode active materials. At the same time, it promotes the rapid decomposition of the binder, and further promotes the rapid separation of waste electrode active materials and the binder.

[0019] The present invention also replenishes the lithium ions lost in the circulation process by regenerating the waste electrode active materials, repairs the structural defects caused by lithium deficiency, and restores its electrochemical performance.

[0020] According to some embodiments of the present invention, the temperature of the low temperature treatment is -200°C to -150°C.

[0021] According to some embodiments of the present invention, the low temperature treatment time is 0.1h~1h.

[0022] The high polymer binder and electrolyte are vitrified by low temperature, and interface peeling stress is generated between the metal current collector and the waste electrode active material due to the difference in thermal shrinkage coefficient, so that elastic adhesion during mechanical peeling is avoided, and separation of the current collector and the waste electrode material is facilitated.

[0023] According to some embodiments of the present application, the microwave power of the microwave pyrolysis is 400W-1600W.

[0024] According to some embodiments of the present application, the microwave power of the microwave pyrolysis is 400W-600W.

[0025] According to some embodiments of the present application, the temperature of the microwave pyrolysis is 350℃-600℃.

[0026] According to some embodiments of the present application, the temperature of the microwave pyrolysis is 450℃-600℃.

[0027] By controlling the temperature in the above range, effective decomposition of the adhesive is promoted, and the performance of the waste electrode material is not adversely affected.

[0028] According to some embodiments of the present application, the time of the microwave pyrolysis is 0.1h-0.5h.

[0029] According to some embodiments of the present application, the regeneration includes high-pressure reaction and microwave sintering.

[0030] According to some embodiments of the present application, lithium hydroxide solution is added during the high-pressure reaction.

[0031] According to some embodiments of the present application, the molar concentration of the lithium hydroxide solution is 1mol / L-2mol / L.

[0032] According to some embodiments of the present application, a modifier is also added during the high-pressure reaction.

[0033] According to some embodiments of the present application, the mass-volume ratio of the waste electrode active material and the lithium hydroxide solution is 1g-2g:10mL.

[0034] According to some embodiments of the present application, the temperature of the high-pressure reaction is 200℃-300℃.

[0035] Li+diffusion to the crystal lattice is promoted under the hydrothermal environment, which is conducive to promoting the regeneration of the positive electrode active material.

[0036] According to some embodiments of the present application, the pressure of the high-pressure reaction is 1MPa-3MPa.

[0037] According to some embodiments of the present invention, the mass ratio of the waste electrode active material to the modifier is 100:3~4.

[0038] According to some embodiments of the present invention, the high pressure reaction time is 4 h to 8 h.

[0039] According to some embodiments of the present invention, the high pressure reaction time is 4 h to 6 h.

[0040] According to some embodiments of the present invention, the waste electrode sheets include waste ternary material electrode sheets.

[0041] According to some embodiments of the present invention, the modifier includes Ti-NH2-MIL-125 (CAS: 1309760-94-8) and MAF-6 ([Zn(C5H7N2)2], wherein C5H7N2 represents the anion of the organic ligand 2-ethylimidazole (Heim) after deprotonation).

[0042] The present invention utilizes the titanium element in the modifier and the small amount of fluorine remaining after thermal decomposition to reduce the influence of residual fluorine; at the same time, NH2 has a certain coordination effect with the transition metal ions in the electrode material; the dissolution of the transition metal elements is reduced; at the same time, the modifier produces oxides and nitrides during the microwave sintering process, which can inhibit side reactions on the surface of the electrode active material and provide lithium ion diffusion channels; thereby further improving the electrical properties of the recycled material.

[0043] According to some embodiments of the present invention, the molar ratio of Ti-NH2-MIL-125 to MAF-6 is 2-3:1.

[0044] According to some embodiments of the present invention, the temperature of the microwave sintering is 400°C to 500°C.

[0045] According to some embodiments of the present invention, the power of the microwave sintering is 400W~600W.

[0046] According to some embodiments of the present invention, the microwave sintering time is 0.1h~0.5h. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0048] Figure 1 This is a schematic structural diagram of a lithium battery recycling device in an embodiment of the present invention.

[0049] Reference numerals: 1. Cryogenic equipment; 11. Liquid nitrogen cavity; 12. Crushing device; 13. Sieving machine; 2. Microwave pyrolysis equipment; 21. Microwave reaction cavity; 22. Tail gas recovery device; 3. Electrode material regeneration equipment; 31. High-pressure reaction kettle; 32. Microwave sintering furnace. DETAILED DESCRIPTION

[0050] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein like reference numerals identify like elements in the figures, and wherein the embodiments described herein are but a few of the embodiments that can be implemented in accordance with the present application. Embodiments described herein are exemplary in nature, and are intended to be illustrative of the present application rather than to limit the same. Furthermore, the following detailed description is intended to complement the accompanying drawings rather than to be inclusive of all aspects of the present application.

[0051] In the description of the present application, it is to be understood that the orientation description, such as up, down, front, back, left, right, and the like, is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0052] In the description of the present application, the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, more than, and the like are understood as not including the number, above, below, and the like are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of indicated technical features.

[0053] In the description of the present application, unless otherwise explicitly limited, the words such as setting, mounting, connecting, and the like should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0054] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and cannot be used to limit the present application, that is, the described examples are only a part of the examples of the present application, but not all the examples. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of the present application.

[0056] In some embodiments of the present invention, a lithium battery recycling device is provided, comprising a cryogenic device 1, a microwave pyrolysis device 2, and an electrode material regeneration device 3; Low temperature equipment 1 is used for separating current collectors and waste battery materials; The microwave pyrolysis device 2 is used to separate the waste electrode active materials and the binder.

[0057] In some embodiments of the present invention, a liquid nitrogen chamber 11 is provided in the cryogenic equipment 1 .

[0058] In some embodiments of the present invention, the liquid nitrogen chamber 22 is provided with a liquid nitrogen injection port.

[0059] In some embodiments of the present invention, a crushing device 12 and a screening machine 13 are further provided in the cryogenic equipment.

[0060] In some embodiments of the present invention, the screening machine 13 is further connected to an eddy current separator.

[0061] The screening machine 13 is provided with a screen to collect the current collector and waste electrode materials.

[0062] The eddy current separator is used to further separate the residual current collector from the waste electrode materials.

[0063] In some embodiments of the present invention, the current collector and waste electrode materials are collected by screening after low-temperature treatment.

[0064] In some embodiments of the present invention, a tail gas recovery device 22 is provided in the microwave pyrolysis device 2 .

[0065] In some embodiments of the present invention, a microwave reaction chamber 21 is provided in the microwave pyrolysis.

[0066] In some embodiments of the present invention, the tail gas recovery device 22 includes a condensation tower, an adsorption tower and a spray tower.

[0067] The condensation tower is used to recover organic solvents, the adsorption tower is used for gas capture, and the spray tower is used for acid gas neutralization.

[0068] In some embodiments of the present invention, the electrode material regeneration device 3 includes a high-pressure reactor 31 and a microwave sintering furnace 32 .

[0069] In the embodiment of the present invention, the waste electrode sheets are waste NCM532 electrode sheets.

[0070] Example 1 This embodiment is a lithium battery recycling method, which consists of the following steps: S1. After the waste electrode sheets are subjected to low-temperature treatment (liquid nitrogen treatment (-196°C), treatment time is 0.2h), the waste battery materials and current collectors are collected; S2, pyrolyzing the waste battery materials by microwave (temperature 500 ° C, time 0.3 h) and collecting the waste electrode active materials; S3, regenerating the waste electrode active materials; The regeneration includes high-pressure reaction, solid-liquid separation (collecting the solid phase during the solid-liquid separation) and microwave sintering of the solid phase (the microwave sintering power is 500 W, the temperature is 450 ° C and the time is 0.2 h); High pressure reaction: The waste electrode active material and lithium hydroxide solution (2 mol / L, the mass volume ratio of the waste electrode active material and the lithium hydroxide solution is 1 g:10 mL) were mixed and then subjected to high pressure reaction (reaction temperature of 220°C, pressure of 2 MPa, and time of 6 h).

[0071] Example 2 This embodiment is a lithium battery recycling method, which consists of the following steps: S1. After the waste electrode sheets are subjected to low-temperature treatment (liquid nitrogen treatment (-196°C), treatment time is 0.2h), the waste battery materials and current collectors are collected; S2, pyrolyzing the waste battery materials by microwave (temperature 500 ° C, time 0.3 h) and collecting the waste electrode active materials; S3, regenerating the waste electrode active materials; The regeneration includes high-pressure reaction, solid-liquid separation (collecting the solid phase during the solid-liquid separation) and microwave sintering of the solid phase (the microwave sintering power is 500 W, the temperature is 450 ° C and the time is 0.2 h); High pressure reaction: The waste electrode active material, modifier and lithium hydroxide solution (2 mol / L, the mass volume ratio of the waste electrode active material to the lithium hydroxide solution is 1 g:10 mL) were mixed and then subjected to high pressure reaction (reaction temperature 300 ° C, pressure 3 MPa, time 6 h); The mass ratio of waste electrode active materials to modifiers is 100:3.

[0072] Modifiers include Ti-NH2-MIL-125 and MAF-6; The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 3:1.

[0073] Example 3 This embodiment is a lithium battery recycling method, which consists of the following steps: S1, collecting waste battery materials and current collectors after low-temperature treatment (liquid nitrogen treatment (-196℃), treatment time is 0.2h) of waste electrode sheets; S2, collecting waste electrode active materials after microwave pyrolysis (temperature is 500℃, time is 0.3h) of waste battery materials; S3, regenerating waste electrode active materials; The regeneration includes high-pressure reaction, solid-liquid separation (collecting solid phase in the solid-liquid separation) and microwave sintering (the power of microwave sintering is 500W, the temperature is 450℃ and the time is 0.2h) of the solid phase; High-pressure reaction: Mixing waste electrode active materials, a modifier and a lithium hydroxide solution (2mol / L, the mass-volume ratio of waste electrode active materials and the lithium hydroxide solution is 1g:10mL) and then high-pressure reaction (the reaction temperature is 220℃, the pressure is 2MPa, the time is 6h); The mass ratio of waste electrode active materials and the modifier is 100:4.

[0074] The modifier includes Ti-NH2-MIL-125 and MAF-6; The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 2:1.

[0075] Example 4 The embodiment is a lithium battery recycling method, which comprises the following steps: S1, collecting waste battery materials and current collectors after low-temperature treatment (liquid nitrogen treatment (-196℃), treatment time is 0.2h) of waste electrode sheets; S2, collecting waste electrode active materials after microwave pyrolysis (temperature is 500℃, time is 0.3h) of waste battery materials; S3, regenerating waste electrode active materials; The regeneration includes high-pressure reaction, solid-liquid separation (collecting solid phase in the solid-liquid separation) and microwave sintering (the power of microwave sintering is 500W, the temperature is 450℃ and the time is 0.2h) of the solid phase; High-pressure reaction: Mixing waste electrode active materials, a modifier and a lithium hydroxide solution (2mol / L, the mass-volume ratio of waste electrode active materials and the lithium hydroxide solution is 1g:10mL) and then high-pressure reaction (the reaction temperature is 220℃, the pressure is 2MPa, the time is 6h); The mass ratio of waste electrode active materials and the modifier is 100:3.8.

[0076] The modifier includes Ti-NH2-MIL-125 and MAF-6; The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 2.1:1.

[0077] Example 5 This embodiment is a lithium battery recycling method, which consists of the following steps: S1. After the waste electrode sheets are subjected to low-temperature treatment (liquid nitrogen treatment (-196°C), treatment time is 0.2h), the waste battery materials and current collectors are collected; S2, pyrolyzing the waste battery materials by microwave (temperature 400 ° C, time 0.3 h) and collecting the waste electrode active materials; S3, regenerating the waste electrode active materials; The regeneration includes high-pressure reaction, solid-liquid separation (collecting the solid phase during the solid-liquid separation) and microwave sintering of the solid phase (the microwave sintering power is 500 W, the temperature is 500 ° C and the time is 0.2 h); High pressure reaction: The waste electrode active material, modifier and lithium hydroxide solution (2 mol / L, the mass volume ratio of the waste electrode active material to the lithium hydroxide solution is 1 g:10 mL) were mixed and then reacted under high pressure (reaction temperature 220 ° C, pressure 2 MPa, time 6 h); The mass ratio of waste electrode active materials to modifiers is 100:3.4.

[0078] Modifiers include Ti-NH2-MIL-125 and MAF-6; The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 2.2:1.

[0079] Example 6 This embodiment is a lithium battery recycling method, which consists of the following steps: S1. After the waste electrode sheets are subjected to low-temperature treatment (liquid nitrogen treatment (-196°C), treatment time is 0.2h), the waste battery materials and current collectors are collected; S2, pyrolyzing the waste battery materials by microwave (temperature 500 ° C, time 0.3 h) and collecting the waste electrode active materials; S3, regenerating the waste electrode active materials; The regeneration includes high-pressure reaction, solid-liquid separation (collecting the solid phase during the solid-liquid separation) and microwave sintering of the solid phase (the microwave sintering power is 500 W, the temperature is 450 ° C and the time is 0.2 h); High pressure reaction: The waste electrode active material, modifier and lithium hydroxide solution (2 mol / L, the mass volume ratio of the waste electrode active material to the lithium hydroxide solution is 1 g:10 mL) were mixed and then subjected to high pressure reaction (reaction temperature 220 ° C, pressure 2 MPa, time 6 h); The mass ratio of waste electrode active materials to modifiers is 100:3.1.

[0080] Modifiers include Ti-NH2-MIL-125 and MAF-6; The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 2.5:1.

[0081] Example 7 This embodiment is a lithium battery recycling method, which differs from Example 6 in that: The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 4:1.

[0082] Example 8 This embodiment is a lithium battery recycling method, which differs from Example 6 in that: The molar ratio of Ti-NH2-MIL-125 and MAF-6 is 1:1.

[0083] Example 9 This embodiment is a lithium battery recycling method, which differs from Example 6 in that: The mass ratio of waste electrode active materials to modifiers is 100:3.

[0084] The modifier is Ti-NH2-MIL-125.

[0085] Example 10 This embodiment is a lithium battery recycling method, which differs from Example 6 in that: The mass ratio of waste electrode active materials to modifiers is 100:3.

[0086] Modified to MAF-6.

[0087] The active material (regenerated positive electrode material and graphite negative electrode in Examples 1 to 10), conductive additive (conductive carbon black) and binder (PVDF) were mixed in a mass ratio of 8:1:1 and dispersed in N-methyl-2-pyrrolidone (NMP) solvent to form a slurry.

[0088] The slurry was then evenly coated on aluminum foil (positive electrode) and copper foil (negative electrode) and dried in a vacuum oven at 120 °C for 8 h.

[0089] After drying, the positive and negative electrodes were cut into circular pieces with diameters of 12 mm and 13 mm, respectively. These components were assembled into standard coin cells (CR2032), with lithium foil as the counter electrode and LP40 electrolyte (1 M LiPF6 in EC / DEC = 1:1, v / v) as the electrolyte, in an argon-filled glove box.

[0090] The cycling performance of the materials was evaluated by constant current charge and discharge tests at room temperature using a Neware battery testing system (CT-4008Tn-5V12A-DB-F, Neware, Shenzhen, China).

[0091] The test process includes three initial activations at 0.1 C, followed by 1000 cycles at 1 C, and calculation of the capacity retention.

[0092] The voltage range of the positive electrode was 3-4.3 V, and the voltage range of the negative electrode was 0.001-2 V. Cyclic voltammetry (CV) tests were performed on an EC-LAB electrochemical workstation, starting from the open circuit voltage and within the voltage range of 3-4.3 V to evaluate the electrochemical performance of the material.

[0093] Table 1

[0094] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A lithium battery recycling device, characterized in that: Including cryogenic equipment, microwave pyrolysis equipment and electrode material regeneration equipment; The low-temperature equipment is used to separate the current collector and waste battery materials; The microwave pyrolysis equipment is used for separating waste electrode active materials and adhesives.

2. The lithium battery recycling equipment according to claim 1, characterized in that: The cryogenic equipment is provided with a liquid nitrogen chamber; And / or, the cryogenic equipment is further provided with a crushing device.

3. The lithium battery recycling equipment according to claim 1, characterized in that: The microwave pyrolysis equipment is provided with a tail gas recovery device.

4. The lithium battery recycling equipment according to claim 1, characterized in that: The electrode material regeneration device includes a high-pressure reactor and a microwave sintering furnace.

5. A lithium battery recycling method, characterized in that: The following steps are involved: collecting waste battery materials and current collectors after low-temperature treatment of waste electrode sheets; collecting waste electrode active materials after microwave pyrolysis of the waste battery materials; The spent electrode active material is regenerated.

6. The method according to claim 5, characterized in that The temperature of the low temperature treatment is -200°C to -150°C; And / or, the low temperature treatment time is 0.1h~1h.

7. The method according to claim 5, characterized in that The microwave power of the microwave pyrolysis is 400W~1600W; and / or, the microwave pyrolysis temperature is 350° C. to 600° C.; And / or, the microwave pyrolysis time is 0.1h~0.5h.

8. The method according to claim 5, characterized in that The regeneration includes high pressure reaction and microwave sintering; and / or, adding lithium hydroxide solution during the high-pressure reaction; And / or, a modifier is added during the high pressure reaction; and / or, the mass volume ratio of the waste electrode active material to the lithium hydroxide solution is 1 g to 2 g: 10 mL; and / or, the temperature of the high pressure reaction is 200° C. to 300° C.; And / or, the pressure of the high-pressure reaction is 1 MPa to 3 MPa; And / or, the mass ratio of the waste electrode active material to the modifier is 100:3~4.

9. The method according to claim 8, characterized in that The modifier includes Ti-NH2-MIL-125 and MAF-6; And / or, the molar ratio of Ti-NH2-MIL-125 to MAF-6 is 2-3:

1.

10. The method according to claim 8, characterized in that The microwave sintering temperature is 400°C to 500°C; And / or, the microwave sintering time is 0.1h~0.5h.

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