Method for recycling positive electrode material of waste lithium ion battery through carbon dioxide laser thermal irradiation

Abstract

The invention provides a method for recycling a waste lithium ion battery positive electrode material through carbon dioxide laser thermal irradiation, and relates to the technical field of lithium ion battery recycling. The method for recycling the positive electrode material of the waste lithium ion battery through carbon dioxide laser thermal irradiation comprises the following steps: paving and fixing a positive electrode plate of the waste lithium ion battery on a glass plate, and scanning the positive electrode plate by adopting carbon dioxide laser; and after laser irradiation, active substances on the positive plate of the waste lithium ion battery are separated from the current collector aluminum foil. The collected active substances are ground and then dispersed in a low-concentration acid solution to be leached, and then a solution containing Li < + >, Co < 2 + >, Ni < 2 + > and Mn < 2 + > is obtained. The technical effects of improving the metal recovery efficiency and reducing the environmental pollution can be achieved by treating the waste positive plate through laser irradiation.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery recycling technology, and more specifically, to a method for recycling waste lithium-ion battery cathode materials using carbon dioxide laser thermal irradiation. Background Technology

[0002] Lithium-ion batteries, with their high energy density, high operating voltage, and safety and environmental friendliness, have been widely used in portable consumer electronics, electric vehicles, and energy storage power stations. Especially in recent years, the strong support for the new energy electric vehicle industry has led to an explosive growth in the demand for lithium-ion batteries. However, lithium-ion batteries have a limited lifespan, and a wave of their retirement is imminent. Furthermore, the lithium, nickel, cobalt, and manganese metals contained in spent lithium-ion batteries are not only heavy metals that pollute the environment, but also valuable resources. Therefore, recycling is a sustainable method to maximize the value of spent lithium-ion batteries while mitigating environmental harm.

[0003] Currently, the main recycling methods are pyrometallurgy and hydrometallurgy. Pyrometallurgy involves melting and calcining spent lithium-ion batteries at high temperatures to recover their metals. This method requires a high-temperature environment, resulting in high energy consumption and the generation of harmful gases (such as HF, SO2, and H2S). After high-temperature calcination, the key metal in spent lithium-ion batteries—lithium—remains in the slag, while metals such as nickel, cobalt, and iron form alloys. This method leads to difficult and inefficient metal recovery, and the high temperature also causes metal loss. Compared to pyrometallurgy, hydrometallurgy offers higher metal recovery efficiency. Hydrometallurgy uses large amounts of strong acids / alkalis and reducing agents to dissolve the metals in spent lithium-ion batteries, converting them into ions that remain in solution. The metal ions are then separated and extracted through complex separation and purification steps (such as precipitation, extraction, and adsorption). However, hydrometallurgy is time-consuming, requires large amounts of strong acids / alkalis, and generates polluting wastewater.

[0004] Although the two methods mentioned above have enabled the industrialization of lithium-ion battery recycling, they still suffer from environmental pollution and low economic efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation, so as to alleviate the technical problem of low recycling efficiency in the prior art.

[0006] In a first aspect, embodiments of the present invention provide a method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation, comprising the following steps: The positive electrode sheet of the waste lithium-ion battery is laid flat and fixed on a glass plate, and the positive electrode sheet is scanned by a carbon dioxide laser. After laser irradiation, the active material on the positive electrode of spent lithium-ion batteries separates from the current collector aluminum foil. The collected active material is ground and then leached in a low-concentration acid solution to obtain a product containing Li. + Co 2+ Ni 2+ Mn 2+ The solution.

[0007] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the laser power of the aforementioned carbon dioxide laser is between 5-60W, and the scanning speed of the carbon dioxide laser is between 10mm / s and 1200mm / s.

[0008] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the laser power of the aforementioned carbon dioxide laser is between 15-45W, and the scanning speed of the carbon dioxide laser is between 20mm / s and 250mm / s.

[0009] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the laser power of the aforementioned carbon dioxide laser is between 20-22W, and the scanning speed of the carbon dioxide laser is between 100mm / s and 140mm / s.

[0010] In conjunction with the first aspect, the present invention provides one possible implementation of the first aspect, wherein the aforementioned low-concentration acid solution is an inorganic acid; The concentration of the low-concentration acid solution is set between 0.01 and 2 mol / L.

[0011] In conjunction with the first aspect, the present invention provides one possible implementation of the first aspect, wherein the aforementioned low-concentration acid solution is hydrochloric acid, nitric acid, and / or sulfuric acid; The concentration of the low-concentration acid solution is set between 0.3 and 0.6 mol / L.

[0012] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the active material on the above-mentioned waste lithium-ion battery positive electrode sheet is in an environment of low-concentration acid solution at a temperature of 50-100 degrees Celsius.

[0013] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the active material on the above-mentioned waste lithium-ion battery positive electrode sheet is placed in an environment with a low concentration acid solution at a temperature of 80 degrees Celsius.

[0014] In conjunction with the first aspect, the present invention provides a possible implementation of the first aspect, wherein the solid-liquid ratio of the active material on the aforementioned waste positive electrode sheet to the low-concentration acid solution is 100:1-2:1.

[0015] In conjunction with the first aspect, embodiments of the present invention provide one possible implementation of the first aspect, wherein, in obtaining Li... + Co 2+ Ni 2+ Mn 2+ After obtaining the solution, sodium carbonate is added to the ionic solution at -10 to 5 degrees Celsius, and the mixture is stirred continuously for 2-3 hours before filtration. Then, the leachate containing lithium carbonate is evaporated and concentrated to obtain high-purity lithium carbonate.

[0016] Beneficial effects: This invention provides a method for recycling cathode materials from waste lithium-ion batteries using carbon dioxide laser thermal irradiation, comprising the following steps: laying and fixing the waste lithium-ion battery cathode sheet flat on a glass plate, scanning the cathode sheet with a carbon dioxide laser; after laser irradiation, the active material on the waste lithium-ion battery cathode sheet separates from the current collector aluminum foil. The collected active material is ground and then dispersed in a low-concentration acid solution for leaching, yielding a material containing Li. + Co 2+ Ni 2+ Mn 2+ The solution.

[0017] Specifically, in the process of recycling the positive electrode material of waste lithium-ion batteries, the positive electrode sheet of the waste lithium-ion battery is first laid flat and fixed on a glass plate. Then, a carbon dioxide laser is used to scan the positive electrode sheet. The carbon dioxide laser can rapidly heat the positive electrode active material on the current collector aluminum foil. The carbon dioxide laser has the ability to heat up instantly. Therefore, after the waste positive electrode is irradiated with high temperature, the conductive agent and binder between the positive electrode active material and the aluminum foil are sintered, so that the positive electrode active material will automatically fall off the current collector aluminum foil. Moreover, the carbon dioxide laser will not affect the current collector aluminum foil, which can easily and quickly separate the positive electrode active material and the current collector aluminum foil. In addition, impurities in the positive electrode active material are removed, and the specific surface area of ​​the positive electrode active material is increased. Therefore, metal ions in the waste positive electrode material can be efficiently leached using a low-concentration acid solution, reducing environmental pollution and improving metal leaching efficiency, thereby improving the efficiency of recycling. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1This is a schematic flowchart of a method for recycling waste lithium-ion battery cathode materials using carbon dioxide laser thermal irradiation, as provided in an embodiment of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0025] See Figure 1As shown, this embodiment provides a method for recycling waste lithium-ion battery cathode materials using carbon dioxide laser thermal irradiation, including the following steps: The waste lithium-ion battery cathode sheet is laid flat and fixed on a glass plate, and scanned using a carbon dioxide laser; after laser irradiation, the active material on the waste lithium-ion battery cathode sheet separates from the current collector aluminum foil. The collected active material is ground and then dispersed in a low-concentration acid solution for leaching, yielding a material containing Li. + Co 2+ Ni 2 + Mn 2+ The solution.

[0026] Specifically, in the process of recycling the positive electrode material of waste lithium-ion batteries, the positive electrode sheet of the waste lithium-ion battery is first laid flat and fixed on a glass plate. Then, a carbon dioxide laser is used to scan the positive electrode sheet. The carbon dioxide laser can rapidly heat the positive electrode active material on the current collector aluminum foil. The carbon dioxide laser has the ability to heat up instantly. Therefore, after the waste positive electrode is irradiated with instantaneous high temperature, the conductive agent and binder between the positive electrode active material and the aluminum foil are sintered, so that the positive electrode active material will automatically fall off the current collector aluminum foil. Moreover, the carbon dioxide laser will not affect the current collector aluminum foil, which can facilitate and quickly separate the positive electrode active material and the current collector aluminum foil. In addition, impurities in the positive electrode active material are removed, and the specific surface area of ​​the positive electrode active material is increased. Therefore, metal ions in the waste positive electrode material can be efficiently leached using a low-concentration acid solution, reducing environmental pollution and improving metal leaching efficiency, thereby improving the efficiency of recycling work.

[0027] In the cathode leaching process, existing technologies use medium-to-high concentration acids and reducing agents to leach the cathode. In these technologies, the reducing agent is used to reduce high-valence metals to low-valence metals (reducing the metal from a high-valence state to a low-valence state), making it easier for the metal to be leached by the medium-to-high concentration acid. However, the carbon dioxide laser thermal irradiation method for recycling waste lithium-ion battery cathode materials provided in this embodiment allows for direct reaction with low-concentration acid after carbon dioxide laser irradiation, without the need for a reducing agent.

[0028] It should be noted that when laser irradiates waste cathodes, the high temperature generated by the laser irradiation can reduce the high-valence metals in the waste cathodes to low-valence states, remove impurities, increase the specific surface area, and thus improve the kinetics and thermodynamics of the leaching process.

[0029] It should be noted that the method for recycling waste lithium-ion battery cathode materials using carbon dioxide laser thermal irradiation provided in this embodiment can directly separate the cathode active material from the aluminum foil. In contrast, existing hydrometallurgical methods require separating the aluminum foil from the cathode active material first, which is time-consuming and labor-intensive. The carbon dioxide laser irradiation method provided in this embodiment does not affect the aluminum foil after irradiation. The high temperature generated by the carbon dioxide laser decomposes the binder between the cathode active material and the aluminum foil, leading to the separation of the active material from the aluminum foil. Therefore, the cathode active material can be directly obtained without the need for pre-treatment separation of the cathode active material and aluminum foil as in existing technologies, thus improving recycling efficiency.

[0030] When the waste lithium-ion battery positive electrode sheet is laid flat and fixed on the glass plate, the current collector aluminum foil is located at the bottom.

[0031] The laser wavelength output by a carbon dioxide laser is typically 10.6 micrometers (far-infrared band). Aluminum has a very low absorption rate in the far-infrared band (10.6 micrometers), usually less than 10%. This means that most of the laser energy is reflected by the aluminum surface rather than absorbed and converted into heat. Therefore, the energy output by the carbon dioxide laser is absorbed by the waste positive electrode active material, improving processing efficiency.

[0032] It should be noted that due to the high-temperature thermal shock effect of the laser, the waste cathode material will change from the originally insoluble Li(Ni) to a more soluble form after irradiation. x Co y Mn z The O2 phase transforms into NiO, CoO, and MnO phases, which lowers the oxidation state of the transition metals, thus facilitating their leaching by low-concentration acid. The acid leaching process does not require strong acids / bases or reducing agents; only a low-concentration acid solution is needed to leach the metal ions.

[0033] It should also be noted that waste cathode materials can be LiCoO2, LiFePO4, and Li(Ni) x Co y Mn z O2, Li(Ni) x Co y A1 z Materials such as O2, of which 0 <x,y,z<1,x+y+z=1。

[0034] In addition, the surface of the waste positive electrode contains an impurity layer, which hinders the solid-liquid reaction between the waste positive electrode and the leaching acid solution. However, the high-temperature thermal shock of the laser decomposes the impurity layer on the surface of the waste positive electrode, thereby greatly improving the metal leaching efficiency.

[0035] It should also be noted that after laser irradiation, the specific surface area of ​​the waste cathode increases, thereby increasing the contact between the waste cathode and the leachate, and thus improving the leaching efficiency of the acid solution.

[0036] In an optional embodiment, after obtaining Li... + Co 2+ Ni 2+ Mn 2+ After obtaining the solution, sodium carbonate is added to the ionic solution at -10 to 5 degrees Celsius, and the mixture is stirred continuously for 2-3 hours before filtration. Then, the leachate containing lithium carbonate is evaporated and concentrated to obtain high-purity lithium carbonate.

[0037] Specifically, in obtaining Li + Co 2+ Ni 2+ Mn 2+ After obtaining the solution, sodium carbonate is added to the ionic solution at 0 degrees Celsius, stirred continuously for 2 hours, filtered, and then the leaching solution containing lithium carbonate is evaporated and concentrated to obtain high-purity lithium carbonate. Alternatively, after obtaining the solution containing Li... + Co 2+ Ni 2+ Mn 2+ After preparing the solution, sodium carbonate is added to the ionic solution at 5 degrees Celsius, and the mixture is stirred continuously for 3 hours before filtration. The leaching solution containing lithium carbonate is then evaporated and concentrated to obtain high-purity lithium carbonate. During the filtration process, nickel carbonate, cobalt carbonate, and manganese carbonate will precipitate, thus enabling the filtration to obtain a high-purity lithium carbonate solution, which can then be concentrated by evaporation to obtain high-purity lithium carbonate.

[0038] Lithium carbonate has high solubility at low temperatures, while other carbonates have low solubility. Therefore, filtration at low temperatures yields a filtrate containing lithium carbonate. Those skilled in the art can set the low-temperature environment according to actual needs, which can be below 5 degrees Celsius.

[0039] In the optional scheme of this embodiment, the laser power of the carbon dioxide laser is between 5-60W, and the scanning speed of the carbon dioxide laser is between 10mm / s and 1200mm / s.

[0040] Specifically, the laser power of the carbon dioxide laser can be set to 5W and the scanning speed to 10mm / s; or, the laser power can be set to 12W and the scanning speed to 50mm / s; or, the laser power can be set to 60W and the scanning speed to 1200mm / s; or, the laser power can be set to 60W and the scanning speed to 600mm / s; or, the laser power can be set to 60W and the scanning speed to 500mm / s; or, the laser power can be set to 15W and the scanning speed to 20mm / s; or, the laser power can be set to 15W and the scanning speed to 150mm / s. Alternatively, the laser power of the carbon dioxide laser can be set to 45W and the scanning speed to 100mm / s; or, the laser power of the carbon dioxide laser can be set to 45W and the scanning speed to 250mm / s; or, the laser power of the carbon dioxide laser can be set to 20W and the scanning speed to 100mm / s; or, the laser power of the carbon dioxide laser can be set to 20W and the scanning speed to 140mm / s; or, the laser power of the carbon dioxide laser can be set to 22W and the scanning speed to 100mm / s; or, the laser power of the carbon dioxide laser can be set to 22W and the scanning speed to 140mm / s; or, the laser power of the carbon dioxide laser can be set to 21W and the scanning speed to 125mm / s.

[0041] In an optional embodiment, the low-concentration acid solution is an inorganic acid; the concentration of the low-concentration acid solution is set between 0.01-2 mol / L.

[0042] The low-concentration acid solution uses inorganic acids such as hydrochloric acid, nitric acid, or sulfuric acid. The concentration of the low-concentration acid solution can be set to 0.01 mol / L, or 0.2 mol / L, or 0.3 mol / L, or 0.4 mol / L, or 0.5 mol / L, or 1 mol / L, or 2 mol / L.

[0043] In an optional embodiment, the active material on the positive electrode of the waste lithium-ion battery is exposed to a low-concentration acid solution at an ambient temperature of 50-100 degrees Celsius.

[0044] Specifically, the active material on the positive electrode of the waste lithium-ion battery is placed in an environment with a low-concentration acid solution at a temperature of 60 degrees Celsius, or at a temperature of 80 degrees Celsius, or at a temperature of 100 degrees Celsius.

[0045] The solid-liquid ratio of the waste cathode material to the low-concentration acid solution is between 100:1 and 2:1. For example, the solid-liquid ratio of the waste cathode material to the low-concentration acid solution is 100:1, or 50:1, or 20:1, or 10:1, or 5:1, or 2:1.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recycling cathode materials from waste lithium-ion batteries using carbon dioxide laser thermal irradiation, characterized in that, Includes the following steps: The positive electrode sheet of the waste lithium-ion battery is laid flat and fixed on a glass plate, and the positive electrode sheet is scanned by a carbon dioxide laser. After laser irradiation, the active material on the positive electrode of spent lithium-ion batteries separates from the current collector aluminum foil. The collected active material is ground and then leached in a low-concentration acid solution to obtain a product containing Li. + Co 2+ Ni 2+ Mn 2+ The solution.

2. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 1, characterized in that, The laser power of carbon dioxide lasers is between 5-60W, and the scanning speed of carbon dioxide lasers is between 10mm / s and 1200mm / s.

3. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 2, characterized in that, The laser power of carbon dioxide lasers ranges from 15 to 45 W, and the scanning speed ranges from 20 mm / s to 250 mm / s.

4. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 3, characterized in that, The laser power of carbon dioxide lasers is between 20-22W, and the scanning speed of carbon dioxide lasers is between 100mm / s and 140mm / s.

5. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 1, characterized in that, The low-concentration acid solution uses an inorganic acid; The concentration of the low-concentration acid solution is set between 0.01 and 2 mol / L.

6. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 5, characterized in that, The low-concentration acid solution is hydrochloric acid, nitric acid, and / or sulfuric acid; The concentration of the low-concentration acid solution is set between 0.3 and 0.6 mol / L.

7. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 5, characterized in that, The active materials on the positive electrode of waste lithium-ion batteries are exposed to low-concentration acid solutions at temperatures between 50 and 100 degrees Celsius.

8. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 7, characterized in that, The active materials on the positive electrode of waste lithium-ion batteries are placed in an environment with a low concentration of acid solution at a temperature of 80 degrees Celsius.

9. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 5, characterized in that, The solid-liquid ratio of the waste cathode material to the low-concentration acid solution is 100:1-2:

1.

10. The method for recycling waste lithium-ion battery cathode materials by carbon dioxide laser thermal irradiation according to claim 1, characterized in that, In obtaining Li + Co 2+ Ni 2+ Mn 2+ After obtaining the solution, sodium carbonate is added to the ionic solution at -10 to 5 degrees Celsius, and the mixture is stirred continuously for 2-3 hours before filtration. The leachate containing lithium carbonate is then evaporated and concentrated to obtain lithium carbonate powder.

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