All-component waste lithium ion battery recycling method based on residual energy driving

Abstract

The invention discloses an all-component waste lithium ion battery recycling method based on residual energy driving. The method comprises the following steps: placing the waste lithium ion battery containing residual electric quantity in a closed environment filled with inert gas, inducing the battery to generate internal short circuit, converting the residual electric quantity into heat, and further triggering a diaphragm and electrolyte to be heated and decomposed to obtain an internal short circuit product; crushing and screening the internal short-circuit product to obtain an undersize product which is black powder No.1 and an oversize product which is a current collector foil; leaching the black powder No.1 by using a leaching agent to obtain slurry; and carrying out wet magnetic separation on the slurry to separate out metal powder, wherein the remainder is a mixture of black powder No.2 and a lithium-containing leachate. According to the method, the recovery process of the waste battery is simplified, the residual energy of the battery is fully utilized, the energy utilization rate and the recovery efficiency are improved, energy loss hardly exists, and the method has remarkable economic benefits and environmental protection benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery recycling, and more specifically to a method for recycling waste lithium ion batteries by all components based on residual energy drive. Background Art

[0002] The recycling of waste lithium batteries has attracted a lot of social attention in recent years. First, waste lithium-ion batteries contain a large number of key metal elements, which have significant resource attributes and economic value; but at the same time, waste lithium batteries also contain a variety of heavy metals, organic matter (including fluorine, phosphorus) and other hazardous substances. If they are not properly handled, they will bear serious environmental risks. At present, the recycling process of waste lithium-ion batteries includes discharge, disassembly, crushing, sorting, and resource recovery of valuable components.

[0003] CN116960500A discloses a method for recycling scrapped lithium-ion batteries. First, charged scrapped single lithium-ion batteries are put into a cold salt water shredder to obtain a mixture A. Then, the mixture A is subjected to ultrasonic treatment and multi-stage filtration to obtain graphite and a mixture B. The mixture B is dried and magnetically separated to obtain a steel shell and a mixture C. The mixture C is further air-separated to obtain a diaphragm material and a mixture D. The mixture D is pyrolyzed. The positive electrode current collector is embrittled and the positive electrode binder is carbonized by heating to obtain a mixture E. Finally, the mixture E is ground and crushed. The positive electrode current collector and the positive electrode material are ground and crushed to obtain a mixture F. The mixture F is then subjected to two-stage sorting to obtain copper foil and positive electrode black powder.

[0004] CN115863815A discloses a method for rapid discharge of waste lithium-ion batteries, which can be simply summarized as immersing one end of the external electrode of the waste lithium-ion battery cell that needs to be discharged into a slurry containing a metal salt solution and a conductive powder for discharge, and then the discharged waste lithium-ion battery is subsequently recycled for metal resources.

[0005] CN111430832A discloses a method for recycling waste ternary lithium-ion batteries without discharging treatment, including charged crushing of waste ternary lithium-ion batteries, recycling of waste electrolyte, separation of diaphragms in waste battery particles, separation of negative electrode active materials in waste battery particles, separation of various carbonaceous components in negative electrode active materials and high-value treatment thereof, enrichment of positive electrode active materials, separation and recycling of negative electrode copper current collectors and positive electrode aluminum current collectors, separation of various components in positive electrode active materials, and recycling of lithium in lithium-containing waste liquid.

[0006] The main drawback of the above-mentioned prior art is that waste batteries need to go through cumbersome pretreatment steps to obtain positive and negative electrode powders before they can be recycled separately, and each step requires high energy and material consumption. Given the current development, such a cumbersome recycling process cannot guarantee the continued existence of its economic benefits. Summary of the invention

[0007] To this end, the technical problem to be solved by the present invention is to provide a method for recycling waste lithium-ion batteries based on residual energy drive. By utilizing the residual energy of waste lithium-ion batteries to induce self-reaction of the battery by instantaneous electrothermal conversion and heat release under the intervention of an external field, the cumbersome battery disassembly process is simplified, and the high-value recovery of all components of waste batteries or modules, including current collectors, negative electrode graphite, and valuable metals such as lithium, nickel, cobalt and manganese in positive electrode materials, is achieved.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0009] A method for recycling waste lithium-ion batteries based on residual energy drive, comprising the following steps:

[0010] Step (1): placing the waste lithium-ion battery containing residual electricity in a closed environment filled with inert gas, inducing an internal short circuit in the waste lithium-ion battery, so that the residual electricity is converted into heat, thereby causing the diaphragm and the electrolyte to decompose by heat; the diaphragm decomposition products, the electrolyte decomposition products and the negative electrode graphite react with the positive electrode material respectively to obtain an internal short circuit product;

[0011] Step (2): crushing and screening the internal short-circuit product, the sieve-under product is black powder No. 1, and the sieve-over product is the current collector foil;

[0012] Step (3): using a leaching agent to leach black powder No. 1 to obtain a slurry; performing wet magnetic separation on the slurry to separate the metal powder, and the remainder is a mixture of black powder No. 2 and a lithium-containing leachate;

[0013] Step (4): filtering the residue, the filter residue is black powder No. 2, and evaporating and crystallizing the lithium-containing leaching solution obtained by filtration to obtain lithium carbonate.

[0014] The enclosed environment described in step (1) needs to have explosion-proof and high-temperature-proof properties. The inert atmosphere is an atmosphere formed by any one or more of inert gases such as nitrogen and argon, and the inert atmosphere can play an explosion-proof role. When a waste lithium-ion battery has an internal short circuit, the residual electricity in the battery is quickly converted into heat, and the diaphragm and electrolyte are decomposed by heat to produce reducing organic matter, which will undergo a thermal reduction reaction with the positive electrode active material together with the carbon in the negative electrode graphite.

[0015] The above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive with all components, when the waste lithium-ion battery is a nickel-cobalt-manganese-oxide lithium battery, the method further comprises the following steps:

[0016] Step (5): acid leaching the black powder No. 2 obtained in step (4) to obtain a manganese-containing leaching solution and graphite slag.

[0017] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive, in step (1), the residual power of the waste lithium-ion battery containing residual power is greater than or equal to 20%. When the residual power of the waste lithium-ion battery is less than 20%, the heat released by the internal short circuit is limited, which will lead to incomplete decomposition of the diaphragm and the electrolyte, and may cause problems such as waste or environmental pollution.

[0018] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy-driven full-component recovery, in step (1), mechanical means or heating means are used to induce internal short circuit in the waste lithium-ion battery. Mechanical means refer to means such as foreign body puncture, mechanical deformation, etc. that can cause internal short circuit in the waste lithium-ion battery. When the waste lithium-ion battery is punctured by foreign objects, mechanically deformed or heated, the diaphragm will be damaged; if there is residual electricity in the waste lithium-ion battery, the damage of the diaphragm will cause internal short circuit in the waste lithium-ion battery.

[0019] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive, when heating means is used to induce internal short circuit in waste lithium-ion batteries, the waste lithium-ion batteries are heated to 150-200°C at a heating rate of 10°C / min. The final heating temperature during heating is determined according to the melting temperature of the diaphragm. If the final heating temperature is too low, the diaphragm will not melt and holes will appear, and thus the internal short circuit cannot be induced. If the final heating temperature is too high, the ambient temperature will continue to rise when the internal short circuit occurs, resulting in a decrease in the safety factor.

[0020] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive, in step (2), a 60-240 mesh sieve is used to screen the crushed internal short-circuit product. When screening the crushed internal short-circuit product, if the mesh number of the sieve is less than 60 mesh, the content of aluminum and copper impurities in the obtained black powder No. 1 will be too high, and if the mesh number is higher than 240 mesh, the loss of black powder No. 1 will be large.

[0021] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive, in step (3), the leaching agent is water or carbonated water; the solid-liquid ratio of black powder No. 1 and the leaching agent is 3-50g / L, the leaching time is 0.5-3h, and the leaching temperature is 20-30°C. The carbonated water in step (3) is water into which carbon dioxide is continuously introduced. When leaching black powder No. 1, a too high solid-liquid ratio, too high a leaching temperature, and too short a leaching time will all lead to a low solubility of lithium carbonate, thereby affecting the recovery rate of lithium.

[0022] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive, in step (3), the magnetic separation time of wet magnetic separation is 30 to 150 minutes. The metal powder separated by wet magnetic separation is transition metal powder. When the magnetic separation time of wet magnetic separation is short, the magnetic separation effect is poor, which will affect the recovery rate of transition metals.

[0023] In the above-mentioned method for recycling waste lithium-ion batteries based on residual energy drive, in step (5), black powder No. 2 is acid-leached with an inorganic acid, the concentration of the inorganic acid is 0.05-3 mol / L, the solid-liquid ratio of black powder No. 2 to the inorganic acid is 2.5-50 g / L, the leaching temperature is 20-60°C, and the acid-leaching time is 0.5-3 hours; the inorganic acid is any one of sulfuric acid, hydrochloric acid and nitric acid. When acid-leaching black powder No. 2, the temperature, time, concentration of the inorganic acid and the solid-liquid ratio of black powder No. 2 to the inorganic acid beyond the above range will affect the recovery rate of manganese element, and will also affect the purity of the graphite slag obtained after acid leaching.

[0024] In the above-mentioned method for full-component recycling of waste lithium-ion batteries based on residual energy driving, the positive electrode material of the waste lithium-ion battery is at least one of lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, nickel cobalt manganese oxide 811, nickel cobalt manganese oxide 622, nickel cobalt manganese oxide 523 and nickel cobalt manganese oxide 111; the waste lithium-ion battery is at least one of a soft-pack battery, a square battery and a cylindrical battery.

[0025] The above method mainly involves the following reaction process:

[0026] (1) Diaphragm decomposition:

[0027] Diaphragm → CO + CH4 + C2H4 + C2H6

[0028] (2) Electrolyte decomposition (taking lithium hexafluorophosphate-ethyl glycolate electrolyte as an example):

[0029] LiPF6→LiF↓+PF5

[0030] PF5+H2O→PF3O+2HF

[0031] 2C2H5OCOOCH3→C2H5OCOOC2H5+CH3OCOOCH3

[0032] CH3OCOOCH3+PF5→CH3OCOOPF4+CH3F

[0033] CH3OCOOPF4→PF3O+CO2+CH4+HF

[0034] CH3OCOOPF4+HF→PF4OH+CO2+CH3F

[0035] C2H5OCOOC2H5+PF5→C2H5OCOOPF4+HF+C2H4

[0036] C2H5OCOOC2H5+PF5→C2H5OCOOPF4+C2H5F

[0037] C2H5OCOOPF4→PF3O+CO2+C2H4+HF

[0038] C2H5OCOOPF4→PF3O+CO2+C2H5F

[0039] C2H5OCOOPF4+HF→PF4OH+CO2+C2H5F

[0040] C2H5OH+C2H4→C2H5OC2H5

[0041] (3) Thermal reduction reaction of positive electrode materials:

[0042] L iTMO2+C / CO / C x H y / C x H y O z →Li2O+TMO+TM+CO / CO2+H2O

[0043] Here, TM represents a transition metal element.

[0044] The technical solution of the present invention achieves the following beneficial technical effects:

[0045] (1) The method provided in the present invention can be directly applied to waste lithium batteries themselves. By inducing internal short circuits through automated equipment, the residual electrical energy in the waste lithium batteries is quickly converted into heat energy, which can trigger a series of chain reactions, decompose the diaphragm and electrolyte, and use the diaphragm decomposition products, electrolyte decomposition products and negative electrode graphite to reduce the positive electrode material, thereby greatly shortening the recovery process of metals such as lithium, nickel and cobalt. That is, the method provided in the present invention achieves relatively thorough component separation and recovery through a shorter recovery process, which reduces process steps, reduces time and resource consumption, and improves recovery efficiency.

[0046] (2) In the prior art, when recycling waste lithium batteries, they are usually discharged first to prevent internal short circuits in the lithium batteries and further thermal runaway of the lithium batteries, which can cause danger. The method of the present invention effectively utilizes the residual power of the battery itself, induces internal short circuits through automated equipment to induce "thermal runaway" of the lithium battery, and uses the energy generated during "thermal runaway" of the lithium battery to drive a series of chemical reactions to complete the recovery of valuable metal elements, thereby maximizing energy utilization.

[0047] (3) The chemical reaction involved in the method provided by the present invention is driven by the conversion of the stored electrical energy into thermal energy through an internal short circuit of the battery itself, thereby greatly improving the energy utilization efficiency.

[0048] (4) During the thermal reduction reaction, lithium oxide reacts with carbon dioxide generated simultaneously to form lithium carbonate. When carbonated water (carbonated water refers to water into which carbon dioxide gas is introduced) is used for leaching, the lithium carbonate with lower solubility generated during the thermal reduction reaction is converted into lithium bicarbonate with higher solubility, thereby increasing its solubility in water. In addition, the lithium oxide that has not completely reacted can also be converted into lithium carbonate and / or lithium bicarbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The method provided in the present invention is a technical flow chart for recycling nickel-cobalt-manganese lithium batteries. DETAILED DESCRIPTION

[0050] Example 1

[0051] (1) A lithium cobalt oxide mobile phone battery with a SOC (State of Charge, indicating the residual power of the battery) of 40% is placed in a sealed box filled with inert gas.

[0052] (2) While ensuring the airtightness of the box, the waste lithium-ion battery is heated (heat driven); during heating, the temperature is raised to 160°C at a rate of 10°C / min. The high temperature causes the separator in the battery to melt due to heat, and holes appear on the separator, which in turn induces an internal short circuit in the waste lithium-ion battery. During an internal short circuit, the residual electricity in the waste lithium-ion battery is quickly converted into heat, and the separator and electrolyte are decomposed by heat to produce reducing organic matter. These reducing organic matter will undergo a thermal reduction reaction with the positive electrode active material together with the carbon in the negative electrode graphite. After this step, an internal short circuit product is obtained.

[0053] (3) The internal short-circuit product is crushed and sieved with a 200-mesh sieve. The material under the sieve is black powder No. 1, and the aluminum foil and copper foil (i.e., the current collector foil) remain on the sieve plate as the material over the sieve.

[0054] (4) Black powder No. 1 is leached with carbonized water to prepare a slurry. The leaching temperature is 25°C, the solid-liquid ratio of black powder No. 1 to carbonized water is 50g / L during leaching, and the leaching time is 2h. After the leaching is completed, the slurry is subjected to wet magnetic separation using a wet magnetic separator, and the magnetic separation time is 60min. The wet magnetic separator separates powdered cobalt from the slurry, and the residue is a mixture of black powder No. 2 and lithium-containing leaching solution. Among them, the main component of black powder No. 2 is graphite slag.

[0055] (5) The residue is filtered, and the filter residue is black powder No. 2. The lithium-containing leaching solution obtained by filtration is used to prepare a lithium carbonate product by an evaporation crystallization method.

[0056] Under the conditions of this embodiment, the lithium leaching rate is 93.88% and the cobalt magnetic separation rate is 90.25%.

[0057] In some other embodiments, water can also be used as a leaching agent when leaching black powder No. 1. The leaching conditions can be adjusted according to actual needs, but the solid-liquid ratio is preferably 3-50 g / L, the leaching time is preferably 0.5-3 h, and the leaching temperature is preferably 20-30°C.

[0058] Example 2

[0059] The technical process of recycling waste lithium-ion batteries in this embodiment is as follows: Figure 1 The specific steps are:

[0060] (1) Place a ternary lithium battery (the positive electrode material is lithium nickel cobalt manganese oxide) with a SOC of 60% in a sealed box filled with inert gas.

[0061] (2) While ensuring the airtightness of the box, the waste battery is punctured by foreign objects (mechanical means) to induce an internal short circuit in the battery. The residual electricity in the waste lithium-ion battery is quickly converted into heat, and the diaphragm and electrolyte are decomposed by heat to produce reducing organic matter. These reducing organic matter will react with the carbon in the negative electrode graphite and the positive electrode active material to undergo thermal reduction reaction. After 5 minutes of puncture, the reaction ends and an internal short circuit product is obtained.

[0062] (3) The internal short-circuit product is crushed and screened, the screening mesh is 200 mesh, and the screened material is black powder No. 1; the aluminum foil and copper foil (current collector foil) remain on the screen plate and are the screened material.

[0063] (4) Black powder No. 1 is leached with carbonized water to prepare a slurry. The leaching temperature is 25°C, the solid-liquid ratio of black powder No. 1 to carbonized water is 1:20 (i.e. 50 g / L) during leaching, and the leaching time is 2 hours. After the leaching is completed, the slurry is subjected to wet magnetic separation using a wet magnetic separator, and the magnetic separation time is 60 minutes. The wet magnetic separator separates powdered nickel-cobalt alloy from the slurry, and the residue is a mixture of black powder No. 2 and lithium-containing leaching solution. Among them, black powder No. 2 mainly contains manganese oxide and graphite slag.

[0064] (5) preparing a lithium carbonate product by using the lithium-containing leaching solution through an evaporation crystallization method.

[0065] (6) Using 1 mol / L sulfuric acid, black powder No. 2 was acid-leached. The acid-leaching time was 2 h, the leaching temperature was 60° C., the leaching solid-liquid ratio was 20 g / L, and after the leaching was completed, a manganese-containing leaching solution and graphite leaching residue were obtained.

[0066] In this embodiment, sulfuric acid is used to acid-leach the black powder No. 2. In some other embodiments, inorganic acids such as hydrochloric acid or nitric acid may also be used to acid-leach the black powder No. 2. The concentration of the inorganic acid is preferably 0.05 to 3 mol / L. The solid-liquid ratio of black powder No. 2 to the inorganic acid is preferably 2.5 to 50 g / L, the leaching temperature is preferably 20 to 60° C., and the acid leaching time is preferably 0.5 to 3 hours.

[0067] Under the conditions of this embodiment, the leaching rate of lithium is 93.88%, the magnetic separation rates of nickel and cobalt are 91.38% and 93.54% respectively, and the leaching rate of manganese is 91.23%.

[0068] Comparative Example 1

[0069] The method for recycling waste lithium cobalt oxide batteries in this comparative example is basically the same as that in Example 1, except that the remaining power of the recycled waste lithium ion batteries is 10%. The remaining steps and parameters in each step are the same as those in Example 1.

[0070] Under the conditions of this comparative example, the lithium leaching rate was 64.35%, and the cobalt magnetic separation rate was 60.9%.

[0071] Comparative Example 2

[0072] The method for recycling waste lithium cobalt oxide batteries in this comparative example is basically the same as that in Example 1, except that when leaching black powder No. 1, the leaching temperature is 40° C. and the leaching time is 15 min. The remaining steps and parameters in each step are the same as those in Example 1.

[0073] Under the conditions of this comparative example, the lithium leaching rate obtained was 45.19%, and the cobalt magnetic separation rate was 90.98%.

[0074] Comparative Example 3

[0075] The method for recycling waste nickel-cobalt-manganese-oxide lithium batteries in this comparative example is basically the same as that in Example 2, the only difference is that when leaching black powder No. 2, 0.05 mol / L sulfuric acid is used to acid-leach black powder No. 2, the solid-liquid ratio of black powder No. 2 to sulfuric acid is 100 g / L, the acid leaching time is 15 min, and the leaching temperature is 25°C.

[0076] Under the conditions of this comparative example, the leaching rate of lithium was 92.61%, the magnetic separation rates of nickel and cobalt were 90.54% and 92.17% respectively, and the leaching rate of manganese was 68.23%.

[0077] Table 1 is a comparison of the recovery effects of Example 1, Comparative Example 1 and Comparative Example 2. Table 2 is a comparison of the recovery effects of Example 2 and Comparative Example 3.

[0078] Table 1

[0079] SOC Carbonization water immersion temperature Carbonization water immersion solid-liquid ratio Carbonization water immersion time Lithium leaching rate Cobalt magnetic separation Example 1 40％ 25℃ 50g / L 2h 93.88％ 90.25％ Comparative Example 1 10％ 25℃ 50g / L 2h 64.35％ 60.9％ Comparative Example 2 40％ 40℃ 50g / L 15min 45.19％ 90.98％

[0080] Table 2

[0081] Acid concentration Pickling temperature Acid leaching solid-liquid ratio Acid leaching time Lithium leaching rate Nickel magnetic separation Cobalt magnetic separation Manganese leaching rate Example 2 2mol / L 60℃ 20g / L 2h 93.88％ 91.38％ 93.54％ 91.23％ Comparative Example 3 0.05mol / L 25℃ 100g / L 15min 92.61％ 90.54％ 92.17％ 68.23％

[0082] From the comparison between Comparative Example 1 and Example 1, it can be seen that when the residual power of the waste lithium-ion battery is too low, the heat released after the internal short circuit is limited, resulting in incomplete decomposition of the diaphragm and the electrolyte, and the lithium and cobalt of the positive electrode material cannot be fully reduced and recovered, resulting in serious waste. In addition, the incompletely decomposed electrolyte and diaphragm may also cause environmental pollution and other problems.

[0083] The conditions for carbonized water leaching of black powder No. 1 in Example 1 are relatively suitable conditions obtained after comprehensive consideration and multiple tests. By comparing Example 1 with Comparative Example 2, it can be seen that when the leaching time is shortened, the loss of lithium leaching amount cannot be compensated by increasing the leaching temperature.

[0084] When the manganese oxide in black powder No. 2 reacts with sulfuric acid, water will be produced. When the acid concentration is too high, the temperature of the acid leaching reaction system is also high, which is more dangerous. When the acid concentration is low and the amount is small, the recovery rate of manganese will also decrease, and the final graphite slag will contain more impurities.

[0085] In addition, in the prior art, there are also some other methods for recycling the positive electrode materials of discarded lithium cobalt oxide batteries, such as the method described in patent CN 115893511 A. This method first requires the discarded lithium ion battery to be discharged, and in order to avoid danger during the recycling process, the positive electrode sheet needs to be manually disassembled after discharge, and the lithium cobalt oxide powder needs to be scraped from the positive electrode sheet, and then the lithium cobalt oxide is reduced using biomass pyrolysis gas. The lithium recovery rate in this method can reach up to 95.44%, which is only less than 2% higher than that in Example 1, but the steps are much more complicated.

[0086] Compared with the methods described in the prior art, the methods provided in the above two embodiments do not require steps such as discharge and manual disassembly. Instead, the waste lithium battery is punctured by foreign objects in an inert atmosphere to induce an internal short circuit in the battery, so that the residual electricity undergoes an instantaneous electrothermal conversion and is completely released. The heat converted from the residual electricity triggers a series of chain reactions, so that the diaphragm and electrolyte of the lithium-ion battery are thermally decomposed. The heat and intermediate products generated during the decomposition process can be used to reduce the lithium and transition metal elements in the positive electrode material. Instead of disassembling the battery, the electrolyte is directly decomposed by thermal short circuit, which is also conducive to preventing problems such as electrolyte contamination that may be caused by disassembling the battery. In other words, the method used in the above embodiments greatly simplifies the recycling process of waste lithium batteries, while making full use of the various components in the waste lithium-ion batteries, avoiding waste, and recovering lithium, cobalt, nickel and manganese with high efficiency. It is an efficient, economical and environmentally friendly recycling method.

[0087] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for recycling waste lithium-ion batteries based on residual energy drive, characterized in that: The following steps are involved: Step (1): placing the waste lithium-ion battery containing residual electricity in a closed environment filled with inert gas, inducing an internal short circuit in the waste lithium-ion battery, so that the residual electricity is converted into heat, thereby causing the diaphragm and the electrolyte to decompose by heat; the diaphragm decomposition products, the electrolyte decomposition products and the negative electrode graphite react with the positive electrode material respectively to obtain an internal short circuit product; Step (2): crushing and screening the internal short-circuit product, the sieve-under product is black powder No. 1, and the sieve-over product is the current collector foil; Step (3): using a leaching agent to leach black powder No. 1 to obtain a slurry; performing wet magnetic separation on the slurry to separate the metal powder, and the remainder is a mixture of black powder No. 2 and a lithium-containing leachate; Step (4): filtering the residue, the filter residue is black powder No. 2, and evaporating and crystallizing the lithium-containing leaching solution obtained by filtration to obtain lithium carbonate.

2. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 1 is characterized in that: When the waste lithium-ion battery is a nickel-cobalt-manganese-oxide lithium battery, the method further comprises the following steps: Step (5): acid leaching the black powder No. 2 obtained in step (4) to obtain a manganese-containing leaching solution and graphite slag.

3. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 1, characterized in that: In step (1), the residual power of the waste lithium-ion battery containing residual power is greater than or equal to 20%.

4. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 3 is characterized in that: In step (1), mechanical means or heating means are used to induce an internal short circuit in the waste lithium-ion battery.

5. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 4 is characterized in that: When heating is used to induce an internal short circuit in the waste lithium-ion battery, the waste lithium-ion battery is heated to 150-200°C at a heating rate of 10°C / min.

6. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 1, characterized in that: In step (2), the crushed internal short-circuit product is sieved using a 60-240 mesh sieve.

7. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 1, characterized in that: In step (3), the leaching agent is water or carbonated water; the solid-liquid ratio of black powder No. 1 to the leaching agent is 3-50 g / L, the leaching time is 0.5-3 h, and the leaching temperature is 20-30° C.

8. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 7 is characterized in that: In step (3), the wet magnetic separation time is 30 to 150 minutes.

9. The method for recycling waste lithium-ion batteries based on residual energy drive according to claim 2, characterized in that: In step (5), black powder No. 2 is acid-leached with an inorganic acid, the concentration of the inorganic acid is 0.05-3 mol / L, the solid-liquid ratio of black powder No. 2 to the inorganic acid is 2.5-50 g / L, the leaching temperature is 20-60° C., and the acid-leaching time is 0.5-3 h; the inorganic acid is any one of sulfuric acid, hydrochloric acid and nitric acid.

10. The method for recycling waste lithium-ion batteries based on residual energy drive according to any one of claims 1 to 9, characterized in that: The positive electrode material of the waste lithium-ion battery is at least one of lithium nickel oxide, lithium cobalt oxide, lithium manganese oxide, nickel cobalt manganese oxide 811, nickel cobalt manganese oxide 622, nickel cobalt manganese oxide 523 and nickel cobalt manganese oxide 111; the waste lithium-ion battery is at least one of a soft-pack battery, a square battery and a cylindrical battery.

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