CN116259878A - Lithium battery graphite negative electrode regeneration method and system based on Joule heat principle - Google Patents
Lithium battery graphite negative electrode regeneration method and system based on Joule heat principle Download PDFInfo
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 210
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- 239000010439 graphite Substances 0.000 title claims abstract description 47
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 25
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 25
- 238000011069 regeneration method Methods 0.000 title claims abstract description 18
- 239000002253 acid Substances 0.000 claims abstract description 66
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- 238000000034 method Methods 0.000 claims abstract description 35
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 34
- 238000010438 heat treatment Methods 0.000 claims abstract description 30
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- 230000001172 regenerating effect Effects 0.000 claims abstract description 9
- 150000003839 salts Chemical class 0.000 claims abstract description 7
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- 229930006000 Sucrose Natural products 0.000 claims description 5
- 238000000227 grinding Methods 0.000 claims description 5
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- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 3
- 239000010406 cathode material Substances 0.000 claims description 3
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- JPVYNHNXODAKFH-UHFFFAOYSA-N Cu2+ Chemical compound [Cu+2] JPVYNHNXODAKFH-UHFFFAOYSA-N 0.000 description 2
- VEQPNABPJHWNSG-UHFFFAOYSA-N Nickel(2+) Chemical compound [Ni+2] VEQPNABPJHWNSG-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 229910001429 cobalt ion Inorganic materials 0.000 description 2
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical compound [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 description 2
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- 239000000126 substance Substances 0.000 description 2
- 239000003513 alkali Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/54—Reclaiming serviceable parts of waste accumulators
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/84—Recycling of batteries or fuel cells
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Abstract
The invention relates to the technical field of graphite electrode regeneration preparation, in particular to a lithium battery graphite negative electrode regeneration method based on a Joule heat principle, which comprises the following steps: charging, namely adding negative electrode graphite powder into a charging machine, and charging the negative electrode graphite powder into a box with an opening through the charging machine; heating, namely conveying the box filled with the negative graphite powder into a discharge heater through a conveyor belt to perform discharge heating; removing impurities, taking out the heated negative electrode graphite powder, adding a dilute acid solution for soaking to remove metal ions and inorganic salt impurities in the negative electrode graphite powder, and recovering high-value metal inorganic salts such as lithium salt and the like from the solution; and (3) carbon coating, namely adding a carbon-rich material into the graphite powder subjected to impurity removal to carry out carbon coating, uniformly mixing, roasting in an inert gas environment, and cooling to obtain the regenerated graphite powder. The invention also provides a system for completing the method for regenerating the negative electrode graphite. The regenerated graphite powder prepared by the invention has excellent electrochemical performance and low preparation cost.
Description
Technical Field
The invention relates to the technical field of graphite electrode regeneration preparation, in particular to a lithium battery graphite negative electrode regeneration method and system based on a Joule heat principle.
Background
The graphite electrode is a novel material and is widely applied to the fields of lithium ion batteries, supercapacitors and the like. Graphite electrodes have a higher energy density, longer life and faster charge and discharge rates than conventional electrodes.
The lithium ion battery is the most common rechargeable battery at present, is widely applied to consumer products such as mobile phones, notebook computers and the like, and is used as an important component in the lithium ion battery, a graphite electrode plays a critical role in the lithium ion energy storage field, and negative graphite powder in the material of the graphite battery can be recycled after the graphite battery is aged.
The main difficulty of graphite powder regeneration is to remove organic additives in the negative electrode graphite, including binders, conductive agents, electrolyte, SEI films and the like. The regeneration process generally adopts thermal impurity removal treatment, and the main current treatment means is to place waste graphite in inert atmosphere for high-temperature calcination, and organic impurities are thermally decomposed in the high-temperature heating process so as to achieve the aim of removing impurities. For example, the Chinese patent publication No. CN201811095515.9 discloses a method for regenerating graphite electrodes of waste lithium ion batteries. Shaping the waste graphite electrode material to obtain graphite powder, and performing acid leaching to remove impurities to obtain purified graphite powder; adding a solution containing alkaline components, controlling the pH of the solution in the reaction process to be 8-10, adding aluminum salt for reaction, generating precipitate for pre-coating, and cleaning to obtain pre-coated graphite powder; calcining the pre-coated graphite powder in an inert atmosphere to obtain the alumina-coated graphite material, wherein the mass of the coating layer accounts for 1-3 wt.% of the graphite.
The above patent suffers from the following disadvantages:
(1) The acid leaching solution after the impurities are removed by acid leaching in the patent also contains a large amount of metal ions which can be recycled, so that the waste negative graphite is not recycled thoroughly;
(2) The graphite powder is coated by the reaction of the alkali solution and the aluminum salt, new metal ion impurities are added in the treatment process, and the recycling cost of the waste negative graphite is increased;
(3) The graphite powder is heated in a calcining manner in the above patent, so that the calcining energy consumption is high, and the electrochemical performance of the calcined graphite powder is poor.
In view of this, we propose a lithium battery graphite negative electrode regeneration method and system based on joule heat principle.
Disclosure of Invention
The invention aims to provide a lithium battery graphite negative electrode regeneration method and system based on the Joule heat principle, so as to solve the problems in the background technology.
In order to achieve the above purpose, the present invention provides the following technical solutions:
a lithium battery graphite negative electrode regeneration method based on the Joule heat principle comprises the following steps:
step 1: charging material
Adding negative electrode graphite powder into a charging machine, charging the negative electrode graphite powder into a box with an opening through the charging machine, and compacting the surface of the box during charging to ensure that the graphite powder is compact and has no gaps;
step 2: heat impurity removal
The method comprises the steps of (1) transferring a box filled with negative graphite powder into a discharge heater through a conveyor belt, carrying out discharge heating on the negative graphite powder by the discharge heater under the protection of inert atmosphere, wherein the discharge heating is carried out for a plurality of times, each discharge needs to wait for material cooling at intervals of several minutes, the discharge voltage is 100-300V, and the discharge time is 1-10 s;
step 3: acid impurity removal
Taking out the heated negative electrode graphite powder, adding a dilute acid solution to soak the negative electrode graphite powder to remove metal ions and inorganic salt impurities in the negative electrode graphite powder, wherein the acid concentration is 0.1-1 mol/L during acid leaching, and recovering high-value metal inorganic salts such as lithium salt and the like from the solution, and the graphite powder after acid leaching needs to be washed with water for 3-5 times to remove acid residues;
step 4: carbon coating
Adding a carbon-rich material into the graphite powder after impurity removal for carbon coating, wherein the mass of carbon element in a carbon source is 0-15% of the mass of the cathode material, grinding and mixing uniformly, roasting for 1-5 hours at 300-600 ℃ in an inert gas environment to carbonize an organic layer on the surface of graphite, and cooling to obtain the regenerated graphite powder.
Preferably, the dilute acid solution added in step 3 for removal of impurities includes, but is not limited to: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hypochlorous acid.
Preferably, the carbon-coated carbon-rich material in step 4 is a high molecular organic resin or a small molecular organic resin.
Preferably, the polymeric organic resin includes, but is not limited to: phenolic resins, polyurethanes and polyoxymethylene, polyethylene glycol, polystyrene; the small molecule organic resins include, but are not limited to: sucrose, glucose, asphalt, petroleum refining products.
The invention also provides a device for completing the lithium battery graphite negative electrode regeneration method based on the joule heat principle, which comprises the following steps: the device comprises a box, a conveyor belt, a charging machine and a discharge heater; the box is an insulating shell, and graphite electrodes are embedded on two side walls of the insulating shell; the conveyor belt is used for sequentially conveying the boxes into the charging machine and the discharging heater along the conveying direction; the charging machine fills negative electrode graphite powder into the box; the discharge heater is used for carrying out discharge heating on the negative graphite powder filled in the box.
Compared with the prior art, the invention has the beneficial effects that:
(1) The waste graphite powder is heated by the discharge heater, and the discharge heater is equipment for heating substances to be heated based on the Joule heat principle, so that the energy consumption in the heating process is lower than that in the traditional calciner. Because graphite powder belongs to conductors as well, the resistance of the waste graphite powder mainly comes from various additives of electrode materials, joule heat generated in the electrifying process directly acts on impurity substances, the temperature of a heating part exceeds 1800 ℃ in the short discharging process of 1 second, and impurities are directly evaporated and digested at the temperature, so that the impurity treatment process is realized, and the electrochemical performance of the regenerated graphite powder is improved.
(2) When the waste negative graphite powder is subjected to impurity removal through the dilute acid solution, the dilute acid solution after impurity removal is treated, and metal ions such as copper ions, lithium ions, cobalt ions, nickel ions, manganese ions and the like in the dilute acid solution can be recovered;
(3) According to the invention, when the graphite powder is coated, the carbon-rich material is adopted for coating, new impurities are not added into the graphite powder in the recovery process, and the carbon-rich material is common high polymer or small polymer organic resin, so that the recovery cost is reduced; the coating layer is carbonized in the heating process and forms an amorphous carbon film structure on the surface of graphite, so that the microstructure defect formed by the graphite in repeated charge and discharge is repaired, and the electrochemical performance of the regenerated graphite is improved.
Compared with the prior art, the method has the advantages of simple process, low recovery energy consumption and cost, high purity of the recovered material, environment-friendly process and no pollution. After joule heat impurity removal and acid impurity removal, electrolyte, SEI film, binder and inorganic impurities attached to the negative graphite are efficiently removed, and coating regeneration can be realized only by hundreds of degrees later. The dilute acid solution used in the method can be recycled after being filtered, so that the green treatment and resource regeneration of the negative electrode graphite material are realized, the added value of the power battery recovery industry is improved, and certain economic and social effects are realized.
Drawings
FIG. 1 is a schematic flow chart of the method of the present invention;
FIG. 2 is a graph showing lithium ion recovery rate of waste graphite powder with low lithium content after acid leaching with dilute acid solutions of different concentrations;
FIG. 3 is a graph showing lithium ion recovery rate of waste graphite powder with high lithium content after acid leaching with dilute acid solutions of different concentrations;
FIG. 4 is a schematic diagram of the system of the present invention;
fig. 5 is a graph showing the electrochemical performance curves of the regenerated graphite powder prepared by the discharge heater and the regenerated graphite powder prepared after calcination in the constant current charge-discharge cycle experiment.
In the figure: 1. a box; 11. a graphite electrode; 2. a conveyor belt; 3. a charging machine; 4. and a discharge heater.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
A lithium battery graphite negative electrode regeneration method and system based on Joule heat principle, as shown in figure 1, the method comprises the following steps:
step 1: charging material
Adding negative electrode graphite powder into a charging machine, and compacting the surface of the negative electrode graphite powder when the negative electrode graphite powder is charged into a box with an opening through the charging machine, so as to ensure that the graphite powder is compact and has no gaps;
step 2: heat impurity removal
The method comprises the steps that a box filled with negative graphite powder is conveyed into a discharge heater through a conveyor belt, the discharge heater performs discharge heating on the negative graphite powder under the protection of inert atmosphere, the discharge heating is performed for a plurality of times, each discharge is performed for waiting for material cooling at intervals of several minutes, the discharge voltage is 100-300V, the discharge time is 1-10 seconds, a small amount of metal copper impurities (the metal copper impurities are derived from a negative copper current collector of a lithium battery) contained in waste graphite powder and needing to be oxidized can be oxidized into oxides or salts in the joule heating process, and thermal impurity removal is realized;
step 3: acid impurity removal
Taking out the heated negative electrode graphite powder, adding a dilute acid solution to soak the powder to remove metal ions and inorganic salt impurities in the negative electrode graphite powder, wherein the acid concentration is 0.1-1 mol/L during acid leaching, and recovering high-value metal inorganic salts such as lithium salt and the like from the solution, the acid leached graphite powder needs to be washed with water for 3-5 times to remove acid residues, and the added dilute acid solution for removing impurities comprises but is not limited to: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hypochlorous acid;
as shown in fig. 2 and 3, in the acid impurity removal process, the lithium ion recovery rate of the dilute acid solution with different concentrations after acid leaching of the waste graphite powder with low lithium content (the lithium ion content in the waste graphite powder is 0.5% -4%), and the lithium ion recovery rate of the waste graphite powder with high lithium content (the lithium ion content in the waste graphite powder is not less than 4%) after acid leaching are shown in fig. 2, the recovery rate is about 90% when the dilute acid solution with 0.1mol/L is adopted for the low lithium content graphite powder, the recovery rate is over 95% when the dilute acid solution with 0.15mol/L is adopted, and the recovery rate is over 99% when the dilute acid solution with 1mol/L is adopted for the low lithium content graphite powder; as can be seen from FIG. 3, the recovery rate of the graphite powder with high lithium content is about 80% when the graphite powder is in a 0.6mol/L dilute acid solution, and is more than 95% when the graphite powder is in a 0.8mol/L dilute acid solution, and is more than 99% when the graphite powder is in a 1mol/L dilute acid solution; therefore, in the acid impurity removal process, a dilute acid solution with proper concentration can be selected for impurity removal according to the lithium ion content in the waste graphite powder, so that the acid impurity removal efficiency of the waste graphite powder is improved.
Step 4: carbon coating
Adding a carbon-rich material into the impurity-removed graphite powder to carry out carbon coating, wherein the mass of carbon elements in a carbon source is 0-15% of the mass of a cathode material, grinding and mixing uniformly, roasting for 1-5 hours at 300-600 ℃ in an inert gas environment to carbonize an organic layer on the surface of graphite, and cooling to obtain regenerated graphite powder, wherein the carbon-coated carbon-rich material is high molecular organic resin or small molecular organic resin, and the high molecular organic resin comprises but is not limited to: phenolic resins, polyurethanes and polyoxymethylene, polyethylene glycol, polystyrene; small molecule organic resins include, but are not limited to: sucrose, glucose, asphalt, petroleum refining products.
Example 2
Example 2 is a method for regenerating a waste graphite powder having a low lithium content based on example 1, the lithium ion content of the waste graphite powder being measured to be 0.85% before regeneration, comprising the steps of:
step 1: charging material
Adding negative electrode graphite powder into a charging machine, and compacting the surface of the negative electrode graphite powder when the negative electrode graphite powder is charged into a box with an opening through the charging machine, so as to ensure that the graphite powder is compact and has no gaps;
step 2: heat impurity removal
The method comprises the steps that a box filled with negative graphite powder is conveyed into a discharge heater through a conveyor belt, the discharge heater performs discharge heating on the negative graphite powder under the protection of inert atmosphere, the discharge heating is performed for 3 times, each discharge is performed for 5 minutes, the material cooling is waited, the discharge voltage is 120V, the discharge time is 2 seconds, and metal copper impurities are not detected in the negative graphite powder after heat impurity removal;
step 3: acid impurity removal
Taking out the heated negative electrode graphite powder, adding a dilute acid solution to soak the powder to remove metal ions and inorganic salt impurities in the negative electrode graphite powder, wherein the acid concentration is 0.15mol/L during acid leaching, and recovering high-value metal inorganic salts such as lithium salt and the like from the solution, the acid leached graphite powder needs to be washed with water for 3 times to remove acid residues, and the added dilute acid solution for removing impurities comprises but is not limited to: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hypochlorous acid; the lithium ion content in the negative electrode graphite powder is 99.2 percent after acid impurity removal;
step 4: carbon coating
Adding phenolic resin into the graphite powder subjected to impurity removal for carbon coating, wherein the mass of carbon element in the phenolic resin is 10% of the mass of the anode material, grinding and mixing uniformly, roasting for 4 hours at 500 ℃ in an inert gas environment to carbonize an organic layer on the surface of the graphite, and cooling to obtain the regenerated graphite powder. And the obtained regenerated graphite powder is made into a lithium ion battery, and the battery capacity of the lithium ion battery is measured to be 78%, and after 1500 charge-discharge cycle experiments, the battery capacity of the lithium ion battery is measured to be 66%.
Example 3
Example 3 is a method for regenerating a waste graphite powder having a high lithium content based on example 1, the lithium ion content in the waste graphite powder being measured to be 5.7% before regeneration, comprising the steps of:
step 1: charging material
Adding negative electrode graphite powder into a charging machine, and compacting the surface of the negative electrode graphite powder when the negative electrode graphite powder is charged into a box with an opening through the charging machine, so as to ensure that the graphite powder is compact and has no gaps;
step 2: heat impurity removal
The method comprises the steps that a box filled with negative graphite powder is conveyed into a discharge heater through a conveyor belt, the discharge heater performs discharge heating on the negative graphite powder under the protection of inert atmosphere, the discharge heating is performed for 5 times, each discharge is performed for 8 minutes, the material cooling is waited, the discharge voltage is 220V, the discharge time is 3 seconds, and metal copper impurities are not detected in the negative graphite powder after heat impurity removal;
step 3: acid impurity removal
Taking out the heated negative electrode graphite powder, adding a dilute acid solution to soak the powder to remove metal ions and inorganic salt impurities in the negative electrode graphite powder, wherein the acid concentration is 1mol/L during acid leaching, and recovering high-value metal inorganic salts such as lithium salt and the like from the solution, the acid leached graphite powder needs to be washed with water for 5 times to remove acid residues, and the added dilute acid solution for removing impurities comprises but is not limited to: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hypochlorous acid; the lithium ion content in the negative electrode graphite powder is 99.9 percent after acid impurity removal;
step 4: carbon coating
Adding sucrose into the graphite powder after impurity removal for carbon coating, grinding and mixing uniformly, roasting at 400 ℃ for 5 hours in an inert gas environment to carbonize an organic layer on the graphite surface, and cooling to obtain the regenerated graphite powder, wherein the mass of carbon element in the sucrose is 12% of that of the negative electrode material. And the obtained regenerated graphite powder is made into a lithium ion battery, the battery capacity of the lithium ion battery is 80%, and the battery capacity of the lithium ion battery is 70% after 1500 charge-discharge cycle experiments.
Example 4
An apparatus as shown in fig. 4, the apparatus of embodiment 2 is a method for regenerating a graphite negative electrode of a lithium battery based on joule heating principle, which is used to complete the method of embodiment 1, and comprises: a box 1, a conveyor belt 2, a charger 3 and a discharge heater 4; the box 1 is an insulating shell, graphite electrodes are embedded on two side walls of the insulating shell, the box in the embodiment is specially customized based on the method to be realized, the whole box 1 is made of the insulating shell, high-temperature resistant plastic materials can be used for manufacturing the box, a high-temperature resistant coating is additionally arranged in the insulating shell, meanwhile, the graphite electrodes are embedded on two side walls of the box 1, and a metal electrode used for a discharge heater 4 is in contact conduction with the graphite electrodes on the side walls of the box 1, so that negative graphite powder filled in the box 1 is subjected to discharge heating; the conveyor belt 2 is used for sequentially conveying the boxes 1 into the charging machine 3 and the discharging heater 4 along the conveying direction, the charging machine 3 is required to compact negative graphite during charging, and the higher the density is after compaction, the full contact between the graphite can be ensured to be beneficial to charge conduction; the charger 3 fills negative electrode graphite powder into the box 1; the discharge heater 4 is used for performing discharge heating on the negative graphite powder filled in the box 1.
It can be seen from the above that:
(1) The invention is to heat the abandoned graphite powder by the discharge heater, the discharge heater is the equipment to heat the material to be heated based on the Joule heat principle, the energy consumption in the heating process is lower than that of the traditional calciner, because the graphite powder is also a conductor, the resistance of the abandoned graphite powder is mainly derived from various additives of the electrode material, the Joule heat generated in the electrifying process directly acts on the impurity materials, the temperature of the heating part exceeds 1800 ℃ in the short discharging process of 1 second, and the impurity is directly evaporated and resolved at the temperature to realize the impurity process in the heat treatment, thus improving the electrochemical performance of the regenerated graphite powder.
(2) When the heated graphite powder is subjected to impurity removal through the dilute acid solution, the dilute acid solution after impurity removal is treated, and metal ions such as copper ions, lithium ions, cobalt ions, nickel ions, manganese ions and the like in the dilute acid solution can be recovered;
(3) According to the invention, when the graphite powder is coated, the carbon-rich material is adopted for coating, new impurities are not added into the graphite powder in the recovery process, and the carbon-rich material is common high polymer or small polymer organic resin, so that the recovery cost is reduced;
as shown in FIG. 5, the electrochemical performance curves of the regenerated graphite powder prepared by the discharge heater and the regenerated graphite powder prepared after calcination are compared when constant current charge and discharge cycle experiments are carried out, and as shown in the graph, the initial battery capacity of the regenerated graphite powder prepared by the invention is about 81%, the initial battery capacity of the regenerated graphite powder prepared by calcination is about 78%, the initial battery capacity of the regenerated graphite powder prepared by calcination is reduced to about 25% after 1500 times of cycle charge and discharge, and the battery capacity of the regenerated graphite powder prepared by the discharge heater can still be ensured to be more than 60%, and the battery capacity of the regenerated graphite powder prepared by the discharge heater is more than 40% after 1700 times of cycle charge and discharge, so that the electrochemical performance of the regenerated graphite powder prepared by the invention is superior to that of the regenerated graphite powder prepared by calcination in the traditional method.
The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments, and that the above-described embodiments and descriptions are only preferred embodiments of the present invention, and are not intended to limit the invention, and that various changes and modifications may be made therein without departing from the spirit and scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (5)
1. The lithium battery graphite negative electrode regeneration method based on the Joule heat principle is characterized by comprising the following steps of:
step 1: charging material
Adding negative electrode graphite powder into a charging machine, charging the negative electrode graphite powder into a box with an opening through the charging machine, and compacting the surface of the box during charging to ensure that the graphite powder is compact and has no gaps;
step 2: heat impurity removal
The method comprises the steps of (1) transferring a box filled with negative graphite powder into a discharge heater through a conveyor belt, carrying out discharge heating on the negative graphite powder by the discharge heater under the protection of inert atmosphere, wherein the discharge heating is carried out for a plurality of times, each discharge needs to wait for material cooling at intervals of several minutes, the discharge voltage is 100-300V, and the discharge time is 1-10 s;
step 3: acid impurity removal
Taking out the heated negative electrode graphite powder, adding a dilute acid solution to soak the negative electrode graphite powder to remove metal ions and inorganic salt impurities in the negative electrode graphite powder, wherein the acid concentration is 0.1-1 mol/L during acid leaching, and recovering high-value metal inorganic salts such as lithium salt and the like from the solution, and the graphite powder after acid leaching needs to be washed with water for 3-5 times to remove acid residues;
step 4: carbon coating
Adding a carbon-rich material into the graphite powder after impurity removal for carbon coating, wherein the mass of carbon element in a carbon source is 0-15% of the mass of the cathode material, grinding and mixing uniformly, roasting for 1-5 hours at 300-600 ℃ in an inert gas environment to carbonize an organic layer on the surface of graphite, and cooling to obtain the regenerated graphite powder.
2. The method for regenerating the graphite negative electrode of the lithium battery based on the joule heating principle as claimed in claim 1, wherein the method comprises the following steps: the dilute acid solution added for removal of impurities in step 3 includes, but is not limited to: hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, hypochlorous acid.
3. The method for regenerating the graphite negative electrode of the lithium battery based on the joule heating principle as claimed in claim 1, wherein the method comprises the following steps: the carbon-coated carbon-rich material in the step 4 is high molecular organic resin or small molecular organic resin.
4. The method for regenerating a graphite negative electrode of a lithium battery based on the joule heating principle as claimed in claim 3, wherein: the polymeric organic resins include, but are not limited to: phenolic resins, polyurethanes and polyoxymethylene, polyethylene glycol, polystyrene;
the small molecule organic resins include, but are not limited to: sucrose, glucose, asphalt, petroleum refining products.
5. A system for performing the method for regenerating a graphite negative electrode of a lithium battery based on the joule heating principle as set forth in any one of claims 1 to 4, comprising: the device comprises a box (1), a conveyor belt (2), a charging machine (3) and a discharge heater (4);
the box (1) is an insulating shell, and graphite electrodes (11) are embedded on two side walls of the insulating shell;
the conveyor belt (2) is used for sequentially conveying the boxes (1) into the charging machine (3) and the discharge heater (4) along the conveying direction;
the charger (3) fills negative electrode graphite powder into the box (1);
the discharge heater (4) is used for carrying out discharge heating on the negative graphite powder filled in the box (1).
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| CN116759687A (en) * | 2023-08-17 | 2023-09-15 | 深圳市杰成镍钴新能源科技有限公司 | Discharging device of retired battery based on discharging particles |
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| CN113594420A (en) * | 2021-09-30 | 2021-11-02 | 中南大学 | Regeneration method of lithium ion battery graphite cathode and regenerated graphite cathode thereof |
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| CN111439748A (en) * | 2020-03-12 | 2020-07-24 | 深圳市德方纳米科技股份有限公司 | Regenerated graphite material and preparation method thereof |
| CN113594420A (en) * | 2021-09-30 | 2021-11-02 | 中南大学 | Regeneration method of lithium ion battery graphite cathode and regenerated graphite cathode thereof |
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| CN116759687A (en) * | 2023-08-17 | 2023-09-15 | 深圳市杰成镍钴新能源科技有限公司 | Discharging device of retired battery based on discharging particles |
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