A method for separating electrode sheets and battery powder, and a method for directional cycling of power batteries.

Abstract

This invention discloses a method for separating electrode sheets and battery powder, as well as a method for directional recycling of power batteries, belonging to the field of battery technology. The method for separating electrode sheets and battery powder includes: reacting the binder between the electrode sheets and battery powder with a reaction reagent to deactivate the binder, resulting in electrode sheets and a slurry containing battery powder; the reaction reagent comprises AlBr3, supercritical carbon dioxide, and fluorinated organic carbides. This method can separate the electrode sheets and battery powder with minimal electrode breakage, avoiding or reducing the dust explosion hazard caused by breakage in existing technologies. The method for directional recycling of power batteries includes: performing solid-liquid separation on the positive electrode slurry obtained by separating the electrode sheets and battery powder; preparing the solid phase obtained after solid-liquid separation into a battery material precursor, which is then mixed with a lithium source and calcined to obtain the battery positive electrode material. This method enables directional recycling of power batteries, achieving pollution reduction and carbon reduction effects.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a method for separating electrode sheets and battery powder, and a method for directional cycling of power batteries. Background Technology

[0002] With the development of new energy vehicles, the volume of power batteries and retired power batteries is constantly increasing. The power battery recycling process is long and crude, which generates many unnecessary safety hazards. For example, in the process of handling the electrode sheets after battery disassembly, separating the electrode sheets from the positive and negative electrode powders is a difficult process. The conventional method is to crush and pyrolyze the electrode sheets and battery powder or crush them after pyrolysis. However, this technology can easily generate dust and pose an explosion hazard because it crushes the electrode sheets into smaller particles.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] One of the objectives of this invention is to provide a method for separating electrode sheets and battery powder to solve the above-mentioned technical problems.

[0005] The second objective of this invention is to provide a method for further directional cycling of power batteries based on the above-mentioned separation method.

[0006] This application can be implemented as follows:

[0007] In a first aspect, this application provides a method for separating electrode sheets and battery powder, which includes the following steps:

[0008] The binder between the electrode sheet and the battery powder is reacted with a reagent to deactivate the binder between the electrode sheet and the battery powder, resulting in an electrode sheet and a slurry containing battery powder.

[0009] The reagents consist of AlBr3, supercritical carbon dioxide, and fluorinated organic carbides.

[0010] In an optional embodiment, the fluorinated organic carbide includes at least one of CF3Cl, CF2Cl2, CF2ClCCl3, and CF2ClCFCl2.

[0011] In an optional embodiment, the total amount of AlBr3 and supercritical carbon dioxide is in a mass ratio of 1:1 to 1:2 to the electrode; the mass ratio of AlBr3 to supercritical carbon dioxide is 1:10 to 1:50.

[0012] The mass ratio of fluorinated organic carbide to electrode is 1:5-1:20.

[0013] In an optional embodiment, the reaction between the binder and the reactant is carried out at 20-35°C for 1-5 hours.

[0014] Secondly, this application also provides a method for directional cycling of a power battery, which includes the following steps: performing solid-liquid separation on the slurry obtained by separating the positive electrode sheet and battery powder according to the above method, preparing the solid phase obtained after solid-liquid separation into a battery material precursor, and then mixing it with a lithium source and calcining it to obtain the battery positive electrode material.

[0015] In an optional embodiment, the preparation of the battery material precursor includes: sequentially subjecting the solid phase to acid leaching, extraction, strong acid back-extraction, and precipitation.

[0016] In an optional embodiment, the acid leaching conditions include: immersing the solid in an acid leaching solution at 60-100°C for 10-24 hours; the acid leaching solution is obtained by mixing acid and hydrogen peroxide.

[0017] In an optional embodiment, the acid is selected from sulfuric acid or hydrochloric acid.

[0018] In an optional embodiment, the mass ratio of acid to solid is 1.5-3:1.

[0019] In an optional implementation, the mass ratio of hydrogen peroxide to acid is 8-15:100.

[0020] In an optional embodiment, extraction is performed using extractant 507; and / or, sulfuric acid or hydrochloric acid is used as a back-extraction agent to back-extract the extract.

[0021] In an optional embodiment, precipitation includes: mixing the back-extraction solution with a precipitant at a pH of 8-9, wherein the precipitant is obtained by mixing NaOH solution and ammonia.

[0022] The concentration of the NaOH solution is 0.8-1.2 mol / L.

[0023] In an optional embodiment, calcination is carried out at 600-700°C for 3-10 hours.

[0024] The beneficial effects of this application include:

[0025] In the method for separating electrode sheets and battery powder provided in this application, AlBr3 acts as an activator to break the CF bond. Then, under the action of fluorinated organic carbides, fluorine atoms tend to migrate from the less fluorinated carbon chain to the more fluorinated carbon chain, that is, the F in the binder is transferred to CF2ClCFCl2 to form CF3CFCl2, thereby destroying the structure of the binder and causing it to lose its adhesiveness. This allows for the separation of electrode sheets and battery powder with reduced electrode breakage, avoiding or reducing the dust explosion hazard caused by breakage in existing technologies. Furthermore, the proposed directional recycling method for power batteries enables directional recycling of power batteries, achieving pollution reduction and carbon reduction effects. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] The following provides a detailed description of the method for separating electrode sheets and battery powder, as well as the method for directional cycling of power batteries provided in this application.

[0028] This application provides a method for separating electrode sheets and battery powder, which includes the following steps:

[0029] The binder between the electrode and the battery powder is reacted with a reagent to deactivate the binder between the electrode and the battery powder, resulting in an electrode and a slurry containing battery powder.

[0030] The aforementioned binder between the electrode sheet and the battery powder is the positive and / or negative electrode obtained from the battery cell. The binder between the electrode sheet and the battery powder is mainly polyvinylidene fluoride (PVDF).

[0031] The reagents consist of AlBr3, supercritical carbon dioxide, and fluorinated organic carbides.

[0032] Fluorinated organic carbides are organic carbides with a high fluorine content, and may include at least one of CF3Cl, CF2Cl2, CF2ClCCl3 and CF2ClCFCl2.

[0033] The binder is placed in the above-mentioned reaction reagents for reaction. AlBr3 acts as an activator, which can break the CF bond and deactivate the binder.

[0034] It should be emphasized that other Lewis acids, such as ZnCl2, cannot be used in this application. Other Lewis acids break the C-C bond (that is, break the C-C bond into smaller molecular segments) rather than the CF bond, and therefore cannot deactivate PVDF.

[0035] Specifically, taking fluorine-containing organic carbides such as CF2Cl and CFCl2 as an example, the reaction principle can be referred to as follows:

[0036] AlBr3 acts as an activator to break the CF bond. Then, under the action of CF2ClCFCl2, fluorine atoms tend to migrate from the less fluorine carbon chain to the more fluorine carbon chain, that is, the F in PVDF is transferred to CF2ClCFCl2 to form CF3CFCl2, thereby destroying the structure of PVDF and causing PVDF to lose its stickiness.

[0037] When the fluorinated organic carbide is CF3Cl, CF2Cl2 or CF2ClCCl3, the reaction principle can be referred to CF2ClCFCl2, and will not be elaborated on here.

[0038] In this application, the total amount of AlBr3 and supercritical carbon dioxide to the mass ratio of the electrode can be 1:1 to 1:2, such as 1:1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, or any other value within the range of 1:1 to 1:2.

[0039] By controlling the total amount of AlBr3 and supercritical carbon dioxide to the mass ratio of the electrode within the above range, the activation effect of the activator can be ensured.

[0040] The mass ratio of AlBr3 to supercritical carbon dioxide can be 1:10 to 1:50, such as 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, or any other value within the range of 1:10 to 1:50.

[0041] When the mass ratio of AlBr3 to supercritical carbon dioxide is less than 1:10, it will cause unnecessary waste; when the mass ratio of AlBr3 to supercritical carbon dioxide is greater than 1:50, the content of AlBr3 will be too low and the activation effect will not be obvious.

[0042] The mass ratio of fluorinated organic carbide to electrode can be 1:5-1:20, such as 1:5, 1:8, 1:10, 1:12, 1:15, 1:18 or 1:20, or any other value within the range of 1:5-1:20.

[0043] When the mass ratio of fluorinated organic carbide to electrode is less than 1:5, it will cause unnecessary waste; when the mass ratio of fluorinated organic carbide to electrode is greater than 1:20, it cannot completely handle the free radical F ions generated by the broken CF bonds.

[0044] In this application, the reaction between the binder and the reaction reagent is carried out at room temperature (e.g., 20-35°C) for 1-5 hours, such as 1 hour, 2.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours, or any other value within the range of 1-5 hours.

[0045] The above-mentioned reaction conditions can completely deactivate PVDF, thereby separating the electrode sheet from the battery powder.

[0046] For reference, the above reaction can be carried out in a supercritical carbon dioxide reactor. After the reaction is completed, the slurry containing battery powder is pumped out, and the separated sheet electrodes are left in the extraction tank and can be taken out as needed.

[0047] It should be noted that the above operation can allow the bonding materials of the positive electrode sheet and the battery powder, as well as the bonding materials of the negative electrode sheet and the battery powder, to react with the reaction reagent independently, or the bonding materials of the positive electrode sheet and the battery powder, as well as the bonding materials of the negative electrode sheet and the battery powder, to react with the reaction reagent together. The specific method used depends on the needs.

[0048] Furthermore, this application also provides a method for directional cycling of a power battery, which includes the following steps: performing solid-liquid separation on the slurry obtained by separating the positive electrode sheet and battery powder according to the above method, preparing the solid phase obtained after solid-liquid separation into a battery material precursor, and then mixing it with a lithium source and calcining it to obtain the battery positive electrode material.

[0049] For reference, the above solid-liquid separation can be carried out by pressure filtration. After pressure filtration, the liquid can be removed to obtain the solid phase (battery powder).

[0050] The preparation of battery material precursors includes: sequentially subjecting the filtered solid to acid leaching, extraction, strong acid back-extraction, and precipitation.

[0051] The acid leaching conditions include: immersing the solid in the acid leaching solution at 60-100℃ for 10-24 hours.

[0052] For reference, the immersion temperature can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃, or any other value within the range of 60-100℃.

[0053] The soaking time can be 10h, 12h, 15h, 18h, 20h, 22h or 24h, or any other value within the range of 10-24h.

[0054] The acid leaching solution is obtained by mixing acid and hydrogen peroxide; wherein the acid is selected from sulfuric acid or hydrochloric acid, and the mass ratio of acid to solid is 1.5-3:1 (such as 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1 or 3:1, etc.), and the mass ratio of hydrogen peroxide to acid is 8-15:100 (such as 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100 or 15:100, etc.).

[0055] The hydrogen peroxide mentioned above, as a strong reducing agent, can reduce high-valence oxides to low-valence substances, thereby improving the leaching effect; on the other hand, it will not introduce other impurities, such as metal elements.

[0056] After acid immersion, the immersion solution was extracted using extractant 507.

[0057] The volume ratio of extractant to impregnation solution can be 1:1. The extraction process can be carried out at room temperature.

[0058] After extraction, sulfuric acid or hydrochloric acid is used as a back-extraction agent to back-extract the extract.

[0059] The volume ratio of the back-extraction agent to the extractant can be 2:1. The back-extraction process can also be carried out at room temperature.

[0060] Precipitation involves mixing the back-extraction solution with a precipitant at a pH of 8-9. The precipitant is prepared by mixing NaOH solution and ammonia.

[0061] The concentration of the NaOH solution can be 0.8-1.2 mol / L.

[0062] In this application, the lithium source for preparing the battery cathode material can be lithium hydroxide or lithium carbonate.

[0063] When lithium carbonate is used, its mass ratio to the battery material precursor can be 1:2.5.

[0064] The calcination of the battery material precursor and the lithium source can be carried out at 600-700℃ (such as 600℃, 620℃, 650℃, 680℃ or 700℃, etc.) for 3-10 hours (such as 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, etc.).

[0065] It should be noted that the preparation process and conditions of battery material precursors and the preparation process and conditions of battery cathode materials from battery material precursors not described in detail in this application can be referred to the corresponding prior art, and will not be elaborated here.

[0066] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0067] Example 1

[0068] A lithium battery recycling company has adopted a brand-new recycling process and introduced supercritical carbon dioxide treatment equipment. After the battery is disassembled, the positive electrode sheet and the binder of the positive electrode powder (with PVDF binder) and the negative electrode sheet and the binder of the negative electrode powder (with PVDF binder) are put into the supercritical carbon dioxide reaction tank together.

[0069] AlBr3 and CF2ClCFCl2 are added to a supercritical carbon dioxide reactor to deactivate the binder PVDF, thereby separating the electrode sheet from the battery powder.

[0070] The mass ratio of AlBr3 to supercritical carbon dioxide was 1:20, the total amount of AlBr3 and supercritical carbon dioxide was in a mass ratio of 1:1 to the electrode, and the mass ratio of CF2Cl / CFCl2 to the electrode was 1:5. The reaction between the binder and the reagents was carried out at room temperature for 1 hour.

[0071] After the reaction is complete, the mixture is allowed to stand, and then the slurry containing battery powder is pumped out. The separated sheet electrodes are left in the supercritical carbon dioxide reaction tank and can be removed as needed.

[0072] The slurry containing battery powder is pumped into a filter press for filtration to obtain a solid phase (battery powder).

[0073] Sampling tests revealed that the Al and Cu impurities in the battery powder were less than 0.2%, and the Al and Cu foils were not significantly broken, with no fine particles generated, thus eliminating the risk factors associated with aluminum powder generation.

[0074] Example 2

[0075] A lithium battery recycling company has adopted a brand-new recycling process and introduced supercritical carbon dioxide treatment equipment. After the battery is disassembled, the positive electrode sheet and the binder of the positive electrode powder (with PVDF binder) and the negative electrode sheet and the binder of the negative electrode powder (with PVDF binder) are put into the supercritical carbon dioxide reaction tank together.

[0076] AlBr3 and CF2ClCFCl2 are added to a supercritical carbon dioxide reactor to deactivate the binder PVDF, thereby separating the electrode sheet from the battery powder.

[0077] The mass ratio of AlBr3 to supercritical carbon dioxide was 1:30, the total amount of AlBr3 and supercritical carbon dioxide to the electrode mass ratio was 1:1, and the mass ratio of CF2Cl / CFCl2 to the electrode mass ratio was 1:10. The reaction between the binder and the reagents was carried out at room temperature for 2 hours.

[0078] After the reaction is complete, the mixture is allowed to stand, and then the slurry containing battery powder is pumped out. The separated sheet electrodes are left in the supercritical carbon dioxide reaction tank and can be removed as needed.

[0079] The slurry containing battery powder is pumped into a filter press for filtration to obtain a solid phase (battery powder).

[0080] Sampling tests revealed that the Al and Cu impurities in the battery powder were less than 0.3%, and the Al and Cu foils were not obviously broken, with minimal surface residue, thus eliminating the risk factors associated with aluminum powder generation.

[0081] Example 3

[0082] A lithium battery recycling company has adopted a brand-new recycling process and introduced supercritical carbon dioxide treatment equipment. After the battery is disassembled, the positive electrode sheet and the binder of the positive electrode powder (with PVDF binder) and the negative electrode sheet and the binder of the negative electrode powder (with PVDF binder) are put into the supercritical carbon dioxide reaction tank together.

[0083] AlBr3 and CF2ClCFCl2 are added to a supercritical carbon dioxide reactor to deactivate the binder PVDF, thereby separating the electrode sheet from the battery powder.

[0084] The mass ratio of AlBr3 to supercritical carbon dioxide was 1:50, the total amount of AlBr3 and supercritical carbon dioxide was in a mass ratio of 1:1 to the electrode, and the mass ratio of CF2Cl / CFCl2 to the electrode was 1:20. The reaction between the binder and the reagents was carried out at room temperature for 1 hour.

[0085] After the reaction is complete, the mixture is allowed to stand, and then the slurry containing battery powder is pumped out. The separated sheet electrodes are left in the supercritical carbon dioxide reaction tank and can be removed as needed.

[0086] The slurry containing battery powder is pumped into a filter press for filtration to obtain a solid phase (battery powder).

[0087] Sampling tests revealed that the Al and Cu impurities in the battery powder were less than 0.5%, and the Al and Cu foils were not obviously broken. There were a small amount of residual positive and negative electrode powder on the aluminum and copper foils, but no fine particles were generated, thus eliminating the risk factors of aluminum powder generation.

[0088] Example 4

[0089] The difference between this embodiment and Example 1 is that: the mass ratio of AlBr3 to supercritical carbon dioxide is 1:10, the total amount of AlBr3 and supercritical carbon dioxide to the electrode mass ratio is 1:1, the mass ratio of CF2Cl to CFCl2 to the electrode mass ratio is 1:10, and the reaction between the binder and the reaction reagent is carried out at room temperature for 5 hours.

[0090] Example 5

[0091] The difference between this embodiment and Embodiment 1 is that the binder between the positive electrode and the battery powder, as well as the binder between the negative electrode and the battery powder, are reacted with the reaction reagents independently.

[0092] Example 6

[0093] This embodiment provides a method for directional cycling of a power battery, which includes the following steps:

[0094] The slurry containing battery cathode powder obtained in Example 5 was filtered by pressure, and the solid obtained by pressure filtration was prepared into a battery material precursor. Then it was mixed with lithium carbonate at a mass ratio of 2.5:1 and calcined at 680°C for 5 hours to obtain the battery cathode material.

[0095] The preparation of the battery material precursor includes: immersing the filtered solid with an acid leaching solution at 80°C for 18 hours; the acid leaching solution is obtained by mixing sulfuric acid and hydrogen peroxide, with the mass ratio of sulfuric acid to solid being 2:1 and the mass ratio of hydrogen peroxide to sulfuric acid being 10:100.

[0096] Subsequently, the impregnation solution was extracted at room temperature using extractant 507, with a volume ratio of extractant to impregnation solution of 1:1. Sulfuric acid was then used as a back-extraction agent to back-extract the extract at room temperature, with a volume ratio of back-extraction agent to extract at 2:1. The back-extraction solution was then mixed with a precipitant at a pH of 8-9. The precipitant was prepared by mixing NaOH solution and ammonia water, wherein the concentration of the NaOH solution was 1 mol / L.

[0097] Comparative Example 1

[0098] A lithium battery recycling company uses pyrolysis to crush battery electrodes. After crushing and sorting, the content of Al and Cu impurities in the positive and negative electrodes in the resulting black powder is tested.

[0099] The above pyrolysis is performed at 400℃ for 2 hours. The crushing process involves adding the pyrolysis product to a crusher for crushing and controlling the powder to be crushed to the micron level.

[0100] The results showed that the content of Al and Cu impurities in the electrode sheet exceeded 3%, and the particles of Al and Cu impurities were relatively fine and concentrated in the range of 8-25 μm. The high impurity content increased the difficulty of subsequent impurity removal.

[0101] Comparative Example 2

[0102] The difference between this comparative example and Example 1 is that the mass ratio of AlBr3 to supercritical carbon dioxide is 1:55.

[0103] Comparative Example 3

[0104] The difference between this comparative example and Example 1 is that the total amount of AlBr3 and supercritical carbon dioxide is in a mass ratio of 1:2.5 to the electrode.

[0105] Comparative Example 4

[0106] The difference between this comparative example and Example 1 is that the mass ratio of CF2Cl to the binder is 1:2.5.

[0107] Comparative Example 5

[0108] The difference between this comparative example and Example 1 is that the mass ratio of CF2Cl to the binder is 1:25.

[0109] Test case

[0110] The same binder was used for the electrode sheets and battery powder to be separated in Examples 1-6 and Comparative Examples 1-5, and the residual Al and Cu rates on the final electrode sheets are shown in Table 1.

[0111] Table 1 Comparison of electrode processing

[0112]

[0113] It can be seen that the method of this application can effectively separate the electrode and battery powder while reducing electrode damage, and the residual rate of Al and Cu on the electrode is low.

[0114] In summary, the method for separating electrode sheets and battery powder provided in this application can separate the electrode sheets and battery powder with minimal damage to the electrode sheets, avoiding or reducing the risk of dust explosion caused by breakage in existing technologies. Furthermore, the directional recycling method for power batteries further provided enables directional recycling of power batteries, achieving pollution reduction and carbon reduction effects.

[0115] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of separating a separator sheet from a battery powder, characterized by, The method comprises the following steps: reacting the binder of the pole piece and the battery powder with a reaction reagent to inactivate the binder between the pole piece and the battery powder, to obtain a pole piece and a slurry containing battery powder; the components of the reaction reagent include AlBr3, supercritical carbon dioxide and fluorine-containing organic carbon compounds; the fluorine-containing organic carbon compounds include at least one of CF3Cl, CF2Cl2, CF2ClCCl3 and CF2ClCFCl2; the total amount of the AlBr3 and the supercritical carbon dioxide is 1:1-1:2 of the mass of the pole piece; the mass ratio of the AlBr3 to the supercritical carbon dioxide is 1:10-1:50; the mass ratio of the fluorine-containing organic carbon compounds to the pole piece is 1:5-1:

20.

2. The method of claim 1, wherein, the reaction of the binder and the reaction reagent is performed at 20-35℃ for 1-5h.

3. A method of directed cycling of a power battery, characterized in that, The method comprises the following steps: solid-liquid separation is performed on the slurry obtained by separating the positive pole piece and the battery powder according to the method of claim 1 or 2, and a solid-phase substance obtained after the solid-liquid separation is prepared into a battery material precursor, which is then mixed with a lithium source, calcined to obtain a battery positive electrode material.

4. The power cell directed cycling method of claim 3, wherein, The preparation of the battery material precursor comprises: sequentially performing acid immersion, extraction, strong acid back extraction and precipitation on the solid-phase substance.

5. The power cell directed cycling method of claim 4, wherein, The conditions of the acid immersion include: immersing the solid-phase substance in an acid immersion liquid at 60-100℃ for 10-24h; the acid immersion liquid is obtained by mixing an acid and hydrogen peroxide.

6. The power cell directed cycling method of claim 5, wherein, The acid is selected from sulfuric acid or hydrochloric acid.

7. The power cell directed cycling method of claim 5, wherein, The mass ratio of the acid to the solid-phase substance is 1.5-3:

1.

8. The power cell directed cycling method of claim 5, wherein, The mass ratio of the hydrogen peroxide to the acid is 8-15:

100.

9. The power cell directed cycling method of claim 4, wherein, extraction is performed using an extraction agent 507; and / or, back extraction is performed on the extraction liquid using sulfuric acid or hydrochloric acid as a back extraction agent.

10. The power cell directed cycling method of claim 4, wherein, The precipitation comprises: mixing the back extraction liquid with a precipitant at a pH value of 8-9, the precipitant being obtained by mixing a NaOH solution and ammonia water; wherein the concentration of the NaOH solution is 0.8-1.2mol / L.

11. The power cell directed cycling method of claim 3, wherein, The calcination is performed at 600-700℃ for 3-10h.

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