Method for integrally recycling decommissioned battery electrode material by one-pot method and application of decommissioned battery electrode material

Abstract

The invention discloses a method for integrally recovering an electrode material of a decommissioned battery by a one-pot method, which comprises the following steps: placing the decommissioned battery in a NaCl solution with the mass fraction of 10-15% wt, discharging for 24-48 hours at the temperature of less than or equal to 45 DEG C, releasing residual electric energy, and then cleaning impurities on the surface of the battery by clean water; the method comprises the following steps: (1) placing the decommissioned battery in a NaCl solution, discharging, releasing residual electric energy, and then cleaning dust and other impurities on the outer surface of the decommissioned battery through a clean water tank; the transferred heat energy breaks chemical bonds such as C-H bonds, carbonization treatment of adhesives such as PVDF is achieved, decommissioned positive and negative electrode materials are preliminarily stripped from an aluminum foil current collector and a copper foil current collector respectively, aluminum scraps, copper scraps, positive electrode powder and negative electrode powder are sequentially separated out by controlling the rotating speed of a cyclone separator, the purified positive and negative electrode powder is prepared into a regenerated electrode material, and the regenerated electrode material is recycled. The method is used for producing new lithium ion batteries or other types of battery products.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling of retired battery electrode materials, and particularly to a method and application for overall recycling of retired battery electrode materials by a one-pot method. Background Art

[0003] Retired lithium batteries contain highly toxic and corrosive substances such as electrolyte solutes and organic solvents. Traditional solutions for treating retired batteries mainly include physical disassembly methods, pyrometallurgy, and hydrometallurgy, etc. Physical disassembly is the simplest treatment method, but the volatilized electrolyte during the disassembly process can cause great harm to the physical health of disassembly workers, and there are also risks of accidental explosion or fire. The removed batteries can only recycle copper electrode plates and aluminum electrode plates. Also, since the positive and negative electrode materials are adhered to the copper and aluminum plates, the recycling rate is extremely low; Pyrometallurgy realizes a relatively complete treatment of batteries through multiple complex processes such as crushing and classification, low-temperature volatilization, multiple screening, and secondary combustion. Although this method has a rapid reaction under high-temperature conditions and relatively high efficiency, and can remove the remaining adhesives, and is suitable for treating a large number of or structurally complex batteries, it is easy to generate harmful gases during the treatment process, resulting in secondary high pollution, and very little precious metals such as lithium in the retired batteries are retained, with low output; The wet treatment method is to directly crush the batteries and then dissolve them directly in a sulfuric acid pool and electrolytically reduce them, which can ensure a recovery rate of over 90%. However, it will encounter environmental protection and high recycling cost problems in the treatment of saturated waste sulfuric acid.

[0004] The above-mentioned methods for retired batteries have deficiencies in terms of recovery efficiency, product purity, energy consumption, cost, and environmental impact. Therefore, it is of great significance to develop a method for recycling retired battery electrode materials that is efficient, environmentally friendly, and low-cost. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a method for overall recycling of retired battery electrode materials by a one-pot method.

[0006] One of the purposes of the present invention is achieved by the following technical solution: A method for overall recycling of retired battery electrode materials by a one-pot method, characterized by comprising the following steps:

[0007] S1: Discharge treatment: Place the retired battery in a NaCl solution with a mass fraction of 10% - 15% wt, and discharge for 24 - 48 hours at a temperature ≤ 45°C to release the residual electrical energy, and then wash the surface impurities of the battery with clean water;

[0008] S2: High-energy water ion cracking: Place the pretreated intact retired battery directly in a rotary cracking furnace, and use high-energy water ions to crack for 4 - 8 hours within the temperature range of 320 - 460°C to strip the positive and negative electrode materials from the current collector;

[0009] S3: Multi-stage cyclone separation: Pass the cracked fragments through a series of three-stage cyclone separators to separately separate aluminum chips, copper chips, positive electrode powder, and negative electrode powder at rotational speeds of 800 - 1200 r / min, 1400 - 1600 r / min, and 2400 - 2600 r / min in sequence.

[0010] S4: Purification and regeneration of electrode powder: Screen and purify the separated positive and negative electrode powders to remove impurities, and prepare the purified powder into regenerated electrode materials.

[0011] Further, the mass fraction of the NaCl solution in step S1 is preferably 12% wt, and the discharge time is 36 hours.

[0012] Further, the cracking temperature of the rotary cracking furnace in step S2 is preferably 380 °C, and the cracking duration is 6 hours.

[0013] Further, the three-stage rotational speeds of the cyclone separator in step S3 are 1000 r / min, 1500 r / min, and 2500 r / min respectively, and the separation efficiency is 95% - 98%.

[0014] Further, the lithium (Li) content in the purified positive electrode powder in step S4 is 3% - 6%, which can be directly used for preparing the electrodes of lithium-ion batteries.

[0015] Application of the one-pot method for overall recycling of retired battery electrode materials, and the regenerated electrode materials are used for producing batteries for 3C digital products, power tool batteries, or energy storage system batteries.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) Place the retired battery in the NaCl solution to discharge completely, release the residual electric energy, and then pass through the clear water tank to wash away impurities such as dust on the outer surface of the retired battery.

[0018] (2) Place the intact retired battery after the discharge and cleaning pretreatment in step S1 in a high-energy water ion rotary cracking furnace, where the high-energy water ions conduct convective heat transfer to the waste batteries in the cracking furnace, and the transferred heat energy breaks chemical bonds such as C - H bonds to achieve the carbonization treatment of binders such as PVDF, so that the retired positive and negative electrode materials are preliminarily peeled off from the aluminum foil and copper foil current collectors respectively.

[0019] (3) Crush the retired battery processed in step S2 into fragments, transport them to a series of multiple cyclone separators by a conveyor belt, and sequentially separate aluminum chips, copper chips, positive electrode powder, and negative electrode powder by controlling the rotational speed of the cyclone separator.

[0020] (4) Separately screen the positive and negative electrode powders obtained in step S3 to remove impurities and unnecessary elements therein. Then, prepare the purified positive and negative electrode powders into regenerated electrode materials for the production of new lithium-ion batteries or other types of battery products.

[0021] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented in accordance with the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically cited preferred embodiments are described in detail below in conjunction with the accompanying drawings. Description of the Drawings

[0022] Figure 1 : Schematic diagram of the one-pot reaction system, showing the discharge, cracking, separation and regeneration processes;

[0023] Figure 2 : SEM image of the regenerated positive electrode material in Example 1 (magnified 5000 times), showing a uniform particle distribution;

[0024] Figure 3 : EDS spectrum of the regenerated positive electrode material in Example 1, confirming the distribution of Li, Co, and Ni elements. Detailed Embodiments

[0025] Next, in combination with the accompanying drawings and specific embodiments, the present invention will be further described. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined with each other to form new embodiments.

[0026] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] Example 1:

[0029] (1) Place the retired battery in a NaCl solution with a mass fraction of 12% wt, discharge it in an environment below 45°C for 36 hours, and then rinse the surface impurities with clean water;

[0030] (2) Place the whole pre-treated retired battery in a rotary cracking furnace, set the cracking temperature at 380°C, and the cracking time at 6 hours, and use high-energy water ions to achieve the carbonization of the binder and the stripping of the electrode material;

[0031] (3) The cracked fragments are processed by a crusher and sent into a three-stage cyclone separator (with rotation speeds of 1000 r / min, 1500 r / min, and 2500 r / min) to separate out aluminum chips, copper chips, positive electrode powder, and negative electrode powder;

[0032] (4) Screen and purify the positive electrode powder to obtain a recycled electrode material with a lithium content of 4.8% for use in preparing new batteries.

[0033] Example 2:

[0034] (1) The discharge treatment is the same as in Example 1;

[0035] (2) Adjust the cracking temperature to 400°C and the cracking time to 6 hours, and the remaining steps are the same as in Example 1;

[0036] (3) The lithium content of the purified positive electrode powder is 5.2%, and the separation efficiency reaches 97%.

[0037] Comparative Example 1:

[0038] (1) The discharge treatment is the same as in Example 1;

[0039] (2) High-energy water ions are not used during the cracking process, and it is only cracked at 320°C for 4 hours in an air atmosphere;

[0040] (3) The lithium content of the separated positive electrode powder is only 2.1%, and there is serious residue of the binder, making it unable to be directly recycled.

[0041] Comparative Example 2:

[0042] (1) The discharge treatment is the same as in Example 1;

[0043] (2) The cracking temperature is adjusted to 400°C, but high-energy water ions are not used, and the cracking time is 6 hours;

[0044] (3) The separation efficiency is 89%, the lithium content of the positive electrode powder is 3.5%, and the impurity content is relatively high.

[0045] Table 1 Detection of the components of the recycled electrode material:

[0046]

[0047] Experimental data and effect verification

[0048] Elemental analysis (Table 1):

[0049] In the cathode powder of Example 1, the Li content is 4.8%, the Co content is 18.3%, and the Ni content is 8.7%; in the cathode powder of Comparative Example 1, the Li content is only 2.1% and the Co content is 12.5%.

[0050] SEM and EDS characterizations ( Figure 2 、 Figure 3 ): The morphology of the cathode material in Example 1 is uniform and there is no binder residue; there are obvious carbonized residues on the surface of the material in Comparative Example 1, which affects the electrochemical performance.

[0051] Economic analysis: In Example 1, the daily water make-up of the water circulation system is 100 kg, and the water fee is 0.7 yuan / day; the electricity cost is 1440 yuan / day (daily treatment of 5 tons), and the comprehensive cost is reduced by 40% compared with the wet method.

[0052] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention fall within the protection scope required by the present invention.

Claims

1. Method for overall recycling of retired battery electrode materials by one-pot method, characterized in that, It includes the following steps: S1: Discharge treatment: Place the retired battery in an NaCl solution with a mass fraction of 10% - 15% wt, discharge for 24 - 48 hours at a temperature ≤ 45°C to release the residual electrical energy, and then clean the impurities on the battery surface with clean water; S2: High-energy water ion cracking: Place the pre-treated complete retired battery directly in a rotary cracking furnace, and use high-energy water ions to crack for 4 - 8 hours in the temperature range of 320 - 460°C to separate the positive and negative electrode materials from the current collector; S3: Multi-stage cyclone separation: Pass the cracked fragments through a series of three-stage cyclone separators to separate aluminum chips, copper chips, positive electrode powder, and negative electrode powder at rotational speeds of 800 - 1200 r / min, 1400 - 1600 r / min, and 2400 - 2600 r / min in sequence; S4: Purification and regeneration of electrode powder: Screen and purify the separated positive and negative electrode powders to remove impurities, and prepare the purified powders into regenerated electrode materials.

2. The recycling method according to claim 1, wherein In step S1, the mass fraction of the NaCl solution is preferably 12% wt, and the discharge time is 36 hours.

3. The recovery method according to claim 1, wherein In step S2, the cracking temperature of the rotary cracking furnace is preferably 380°C, and the cracking duration is 6 hours.

4. The recycling method according to claim 1, characterized in that, In step S3, the three-stage rotational speeds of the cyclone separator are 1000 r / min, 1500 r / min, and 2500 r / min respectively, and the separation efficiency is 95% - 98%.

5. The recycling method according to claim 1, wherein, In step S4, the lithium (Li) content in the purified positive electrode powder is 3% - 6%, which can be directly used to prepare the electrodes of lithium-ion batteries.

6. An application of any one of the methods of claims 1-5, characterized in that, The regenerated electrode materials are used to produce batteries for 3C digital products, power tool batteries, or energy storage system batteries.

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