Method for recycling lithium battery pole piece, method for recycling lithium battery and active material

Abstract

The invention discloses a method for recycling a lithium battery pole piece, a method for recycling a lithium battery and an active material. The method for recycling the lithium battery pole piece comprises the steps that the lithium battery pole piece placed in an electrolytic tank is connected with a negative electrode of an external power source, and the lithium battery pole piece comprises a current collector and an active material layer located on at least one side of the current collector; connecting the anode in the electrolytic tank with the positive pole of the external power supply; and electrifying the electrolytic tank at the voltage of 2V-6V, so that the active material layer is separated from the current collector. The use of chemical reagents is reduced, the generation of wastewater, waste gas and solid wastes is reduced, and secondary pollution is avoided.

Description

Technical Field

[0001] The present application relates to the field of lithium battery recycling, and specifically, to a method for recycling lithium battery pole pieces, a method for recycling lithium batteries, and active materials. Background Art

[0002] As a representative of new energy storage technology, lithium batteries are widely used in portable electronic devices, electric vehicles, and large-scale energy storage systems. The new energy market has a growing demand for key metals in batteries. At the same time, the ecological and environmental problems caused by discarded electronic products and discarded batteries in them are becoming increasingly prominent. However, with the increase in service life and the attenuation of battery performance, a large number of discarded lithium batteries pose a potential threat to the environment and human health. The recycling of lithium batteries not only helps to reduce environmental pollution, but is also an important way to achieve resource recycling. Therefore, the recycling of lithium batteries has become a key topic in the study of urban mineral resources. Lithium batteries contain lithium, cobalt, manganese, nickel and other elements. Although these materials are of high value, they also have certain environmental pollution. At the same time, due to the shortage of lithium resources in the upstream and the influence of policies of various countries in the middle and downstream, the serious mismatch between supply and demand has led to a sharp fluctuation in raw material prices. The need to explore new technologies for power battery recycling and accelerate the layout of the power battery recycling industry has become increasingly urgent. The development of effective methods for recycling discarded lithium batteries is a major challenge that needs to be addressed urgently. Summary of the invention

[0003] In the first aspect of the present application, the present application proposes a method for recycling lithium battery pole pieces, comprising: connecting a lithium battery pole piece placed in an electrolytic cell to the negative electrode of an external power source, the lithium battery pole piece comprising a current collector and an active material layer located on at least one side of the current collector; connecting an anode placed in the electrolytic cell to the positive electrode of the external power source; and subjecting the electrolytic cell to a power-on treatment at a voltage of 2V-6V, so that the active material layer is separated from the current collector.

[0004] The method for recycling lithium battery pole pieces proposed in the present application is to place the lithium battery pole pieces to be recycled and the anode in an electrolytic cell at the same time, and respectively connect them to an external power source to form a conductive path, so that a water electrolysis reaction occurs on the lithium battery pieces to be recycled, and hydrogen is generated on the current collector. The hydrogen gathers to form bubbles, and the bubbles expand and overflow to separate the active material layer on the lithium battery pole piece from the current collector.

[0005] In some embodiments, during the power-on process, the current density on the lithium battery electrode is 0.001A / cm 2 -0.005A / cm 2 . Thus, hydrogen can be generated in a more controllable manner.

[0006] In some embodiments, the duration of the power-on treatment is 5s-200s. Thus, after the power-on treatment for the aforementioned power-on time, the active material layer on the lithium battery pole piece can be relatively completely separated from the current collector.

[0007] In some embodiments, the solute of the electrolyte in the electrolytic cell includes at least one of potassium nitrate, sodium nitrate, potassium sulfate, and sodium sulfate. Thus, by conducting an electric current treatment in the electrolyte containing the aforementioned solute, hydrogen can be uniformly and quickly generated on the lithium battery pole piece, so that the active material layer on the lithium battery pole piece is separated from the current collector.

[0008] In some embodiments, the concentration of the electrolyte is 0.5 mol / L-1.4 mol / L. Thus, the electrolyte solution has good conductivity, which is conducive to the occurrence of water electrolysis reaction.

[0009] In some embodiments, the method further comprises: washing and drying the separated active material layer, thereby facilitating purification of the active material in the separated active material layer for subsequent use or processing.

[0010] In some embodiments, the lithium battery pole piece includes a positive pole piece and / or a negative pole piece, the positive pole piece includes a positive current collector and a positive active material layer located on at least one side of the positive current collector, the positive active material layer includes a positive active material, and the positive active material includes at least one of a nickel-cobalt-manganese ternary material, a nickel-cobalt-aluminum ternary material, lithium iron phosphate, lithium cobalt oxide, and lithium manganese oxide. Therefore, in the process of recovering active materials in the method for recycling lithium battery pole pieces proposed in the present application, the active materials in the lithium battery pole pieces will basically not react, and the method can be applied to a variety of different lithium battery pole pieces.

[0011] In the second aspect of the present application, the present application proposes a method for recycling lithium batteries, comprising: disassembling the lithium battery to obtain the lithium battery pole piece; recycling the lithium battery pole piece using the method for recycling the lithium battery pole piece proposed in the present application. In this way, the discarded lithium batteries can be recycled, the active materials with higher value therein can be collected, and the various materials in the lithium battery can be further processed and reused.

[0012] In some embodiments, before disassembling the lithium battery, the process further includes: discharging the lithium battery, wherein the discharging process includes at least one of a chemical solution immersion method and an external resistor discharge method, so that the energy still stored in the lithium battery can be fully released.

[0013] In the third aspect of the present application, the present application proposes an active material, which is recovered by using the method for recycling lithium battery electrode sheets proposed in the present application. Therefore, the recovered active material has a wide range of sources and low cost, which can effectively reduce the manufacturing cost of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0015] Figure 1 A schematic diagram of the electrochemical delamination of the current collector and the battery active material of the present application;

[0016] Figure 2 This is a picture of the separation process of the positive electrode active material and the aluminum foil in one embodiment of the present application;

[0017] Figure 3 This is a picture of the separation process of the negative electrode active material and the copper foil in one embodiment of the present application;

[0018] Figure 4 This is a picture of the disassembled cylindrical lithium electron in Example 1 of the present application;

[0019] Figure 5 This is a picture of the positive electrode of the cylindrical lithium electron in Example 1 of the present application;

[0020] Figure 6 This is a picture of the negative electrode of the cylindrical lithium electron in Example 1 of the present application;

[0021] Figure 7 This is a picture of the aluminum foil after separation in Example 1 of the present application;

[0022] Figure 8 This is a picture of the positive electrode active material after separation in Example 1 of the present application;

[0023] Fig. 9 The XRD diagram of the aluminum foil (bottom) and the positive electrode active material (top) after separation in Example 1 of the present application;

[0024] Fig.10 The metal weight percentages in the positive electrode active material / aluminum foil, the separated aluminum foil, and the separated positive electrode active material of the cylindrical lithium electron in Example 1 of the present application;

[0025] Fig.11 This is the XPS full spectrum of the positive electrode active material / aluminum foil of the cylindrical lithium electron, the positive electrode active material after separation, and the aluminum foil after separation in Example 1 of the present application;

[0026] Fig.12This is an XPS full spectrum diagram of the cylindrical lithium electron in Example 1 of the present application, which is magnified in the binding energy range of 0V-100V;

[0027] Fig.13 The XPS spectra of the cylindrical lithium electron positive electrode active material / aluminum foil (bottom) and the separated battery positive electrode active material (top) in Example 1 of the present application;

[0028] Fig.14 is the metal loss mass percentage of the cylindrical lithium electron in Example 1 of the present application measured according to the content in the electrolyte;

[0029] Fig.15 This is a picture of the copper foil after separation in Example 2 of the present application;

[0030] Fig.16 This is a picture of the negative electrode active material after separation in Example 2 of the present application;

[0031] Fig.17 XRD diagram of the copper foil (bottom) and the negative electrode active material (top) after the separation of the cylindrical lithium electrons in Example 2 of the present application;

[0032] Fig.18 This is a picture of the positive electrode sheet of the LFP soft-pack battery in Example 3 of the present application, and the inset is a picture of the LFP soft-pack battery;

[0033] Fig.19 This is a picture of the negative electrode sheet of the LFP soft-pack battery in Example 3 of the present application;

[0034] Fig. 20 The XRD pattern of the aluminum foil after separation in Example 3 of the present application, and the inset is a picture of the aluminum foil after separation;

[0035] Fig.21 This is the XRD spectrum of the positive electrode active material after separation in Example 3 of the present application, and the inset is a picture of the positive electrode active material after separation;

[0036] Fig. 22 The metal weight percentage of the positive electrode active material / aluminum foil, the separated aluminum foil, and the separated positive electrode active material in the LFP soft pack battery in Example 3 of the present application;

[0037] Fig.23 The mass loss of metal during the separation of the LFP soft pack battery measured by the elements dissolved in the electrolyte in Example 3 of the present application;

[0038] Fig.24 This is a picture of the copper foil after separation in Example 4 of the present application;

[0039] Fig.25 This is a picture of the negative electrode active material after separation in Example 4 of the present application;

[0040] Fig.26 This is a picture of the positive electrode sheet of the NCM soft-pack battery in Example 5 of the present application, and the inset is a picture of the NCM soft-pack battery;

[0041] Fig. 27 This is a picture of the negative electrode sheet of the NCM soft-pack battery in Example 5 of the present application;

[0042] Fig.28 This is the XRD spectrum of the aluminum foil after separation of the NCM soft pack battery in Example 5 of the present application, and the inset is a picture of the aluminum foil after separation;

[0043] Fig.29 This is the XRD spectrum of the positive electrode active material after separation of the NCM soft pack battery in Example 5 of the present application, and the inset is a picture of the positive electrode active material after separation;

[0044] Fig.30 The metal weight percentages of the positive electrode active material / aluminum foil, the separated aluminum foil, and the separated positive electrode active material in the NCM soft pack battery in Example 5 of the present application;

[0045] Fig.31 The mass loss of metal during the separation process of the NCM soft pack battery measured by the elements dissolved in the electrolyte in Example 5 of the present application;

[0046] Fig.32 This is a picture of the copper foil after separation in Example 6 of the present application;

[0047] Fig.33 This is a picture of the negative electrode active material after separation in Example 6 of the present application. DETAILED DESCRIPTION

[0048] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the drawings, but unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0050] The terms "including" and "having" in the specification and claims of the present application and any modifications thereof are open expressions, that is, including the contents specified in the present application but not excluding other contents.

[0051] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0052] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0053] In the recycling process of lithium battery pole pieces, the separation of the current collector and the active material layer is the key first step. Traditional recycling technologies mainly include two methods: pyrometallurgy and hydrometallurgy. Pyrometallurgy recycling technology is based on a high-temperature smelting process. By heating the battery components to a certain temperature, the metal and non-metal materials in the battery undergo physical and chemical changes, thereby separating and recovering valuable metal components. However, this process consumes a lot of energy and may produce toxic gases and dust, causing environmental pollution. Wet recovery technology is based on the principles of chemical dissolution and precipitation. It uses suitable chemical solvents (such as acid, alkali or salt solutions) to dissolve the electrode active materials in the battery, thereby achieving the separation and recovery of metal ions. However, there are problems such as large amounts of chemical reagents used and the risk of secondary pollution.

[0054] The technical solution of the present application generates gas on the lithium battery pole piece by connecting an external power supply. The gas expands to separate the active material from the current collector to achieve the recycling of the lithium battery pole piece. The method of recycling lithium battery pole pieces of the present application is energy-saving, efficient and environmentally friendly. In addition, the purity of the recovered electrode active materials and current collectors is high, which is conducive to the efficient recovery and recycling of valuable metal elements such as lithium, cobalt, nickel, etc. in discarded lithium batteries. At the same time, it also reduces the use of chemical reagents, reduces the generation of wastewater, waste gas and solid waste, and alleviates secondary pollution.

[0055] In the first aspect of the present application, the present application proposes a method for recycling lithium battery pole pieces, comprising: connecting a lithium battery pole piece placed in an electrolytic cell to the negative electrode of an external power source, the lithium battery pole piece comprising a current collector and an active material layer located on at least one side of the current collector; connecting an anode placed in the electrolytic cell to the positive electrode of the external power source; and subjecting the electrolytic cell to a power-on treatment at a voltage of 2V-6V, so that the active material layer is separated from the current collector.

[0056] The method for recycling lithium battery pole pieces proposed in this application refers to Figure 1, the lithium battery pole piece to be recycled and the anode of the electrolytic cell are placed in the electrolytic cell at the same time, and are respectively connected to an external power source to form a conductive path. After power is turned on, water electrolysis reaction occurs on the current collector of the lithium battery pole piece to be recycled, and hydrogen is generated on the current collector. Figure 2 and Figure 3 , hydrogen gathers to form bubbles, and the bubbles expand and detach from the current collector, so that the active material layer on the lithium battery pole piece is separated from the current collector. During the power-on treatment, the substances in the current collector or the active material layer do not participate in the reaction, so the physical and chemical properties of the two themselves will not change. The current collector and active material obtained after separation are of high purity. No chemical reagents are used to treat the current collector and the active material layer during the recycling process, thereby reducing the additional chemical waste generated by the recycling of lithium battery pole pieces, which is more environmentally friendly.

[0057] In some embodiments, during the power-on process, the current density on the lithium battery electrode is 0.001A / cm 2 -0.005A / cm 2 .

[0058] When the current density on the lithium battery pole piece is within the above range, hydrogen can be generated on the surface of the current collector in a relatively controllable manner. Hydrogen bubbles are continuously formed and expanded, and sufficient mechanical force is generated to cause the active material layer disposed on the current collector to bubble, break or peel off as a whole, thereby separating the current collector from the active material layer.

[0059] In some embodiments, the duration of the power-on treatment is 5s-200s. During the power-on treatment, the process of electrolysis and generation of hydrogen on the lithium battery pole piece causes the internal gas pressure of the bubbles to increase continuously, and a separation force of increasing and opposite directions is applied to the current collector and the active material layer between the current collector and the active material layer. After the aforementioned power-on treatment time, the active material layer on the lithium battery pole piece can be relatively completely separated from the current collector.

[0060] In some embodiments, the solute of the electrolyte in the electrolytic cell includes at least one of potassium nitrate, sodium nitrate, potassium sulfate, and sodium sulfate. The electrolyte containing the solute is subjected to an electric current treatment, and hydrogen is uniformly and rapidly generated on the lithium battery pole piece, so that the active material layer on the lithium battery pole piece is separated from the current collector. In addition, the electrolysis only generates hydrogen, and only the solvent water is consumed in the electrolyte, thereby reducing the chemical waste generated by the introduction of chemical reagents that react with the current collector or active material layer during the recovery of the lithium battery pole piece.

[0061] In some embodiments, the concentration of the electrolyte is 0.5 mol / L-1.4 mol / L. Within the above electrolyte concentration range, the electrolyte solution has good conductivity, which is conducive to the occurrence of water electrolysis reaction. The anode, the lithium battery pole piece to be recycled, and the external power supply form a good conductive path, the water electrolysis reaction rate is more appropriate, and the voltage required for the power-on treatment is lower.

[0062] In some embodiments, the method further comprises: washing and drying the separated active material layer, thereby reducing impurities adhering to the active material, facilitating purification of the active material in the separated active material layer, and facilitating subsequent use or processing.

[0063] In some embodiments, the lithium battery pole piece includes a positive pole piece and / or a negative pole piece, the positive pole piece includes a positive current collector and a positive active material layer located on at least one side of the positive current collector, the positive active material layer includes a positive active material, and the positive active material includes at least one of a nickel-cobalt-manganese ternary material, a nickel-cobalt-aluminum ternary material, lithium iron phosphate, lithium cobalt oxide, and lithium manganese oxide. Therefore, in the process of recovering active materials, the method for recovering lithium battery pole pieces proposed in the present application utilizes bubbles formed by hydrogen generated by electrolysis of water to provide mechanical force, so that the current collector and the active material layer in the lithium battery pole piece are separated. The active materials in the lithium battery pole piece basically do not react, so the method for recovering lithium battery pole pieces proposed by itself will not be limited by the chemical properties of the active substances, so the method can be applied to a variety of different lithium battery pole pieces.

[0064] In the second aspect of the present application, the present application proposes a method for recycling lithium batteries, comprising: disassembling the lithium batteries to obtain lithium battery pole pieces; and recycling the lithium battery pole pieces using the method for recycling lithium battery pole pieces proposed in the present application.

[0065] Thus, discarded lithium batteries can be recycled. The various components of lithium batteries can be separated by disassembly. The present application proposes a method for recycling lithium battery pole pieces, which can completely separate and collect the active materials and metal foils with recycling value in the lithium battery pole pieces, thereby further processing and recycling various materials in the lithium battery, which is conducive to reducing the environmental problems caused by discarded lithium batteries.

[0066] In some embodiments, before disassembling the lithium battery, the method further includes: discharging the lithium battery, wherein the discharge treatment includes at least one of a chemical solution immersion method and an external resistor discharge method.

[0067] Lithium batteries have a minimum cut-off voltage limit, so discarded lithium batteries still have a certain amount of electricity. Disassembling and recycling lithium batteries while they are charged may cause a short circuit between the positive and negative electrodes, posing certain safety hazards. Before recycling lithium batteries, discharging them can fully release the energy still stored in the lithium batteries, which is conducive to the safe recycling of lithium battery electrodes.

[0068] In the third aspect of the present application, the present application proposes an active material, which is recovered by using the method for recycling lithium battery electrode sheets proposed in the present application. Since the method for recycling lithium battery electrode sheets proposed in the present application uses mechanical force to separate the active material from the lithium battery electrode sheets, the recovered active material has a wide range of sources and low recycling costs, which can effectively reduce the manufacturing cost of the battery.

[0069] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0070] Example 1

[0071] Discarded cylindrical lithium batteries were used as experimental materials (model: flat head 5550mWh).

[0072] S1. Discharge treatment: Using the salt solution immersion method, the discarded cylindrical lithium battery with intact appearance and no damage is immersed in 200mL of 10% sodium chloride solution by mass for 24 hours.

[0073] S2. Disassembly: Disassemble the cylindrical lithium battery after discharge and remove the battery shell with scissors ( Figure 4 ); the disassembled positive electrode sheet, negative electrode sheet and separator were placed in a fume hood for 6 hours to obtain a positive electrode active material loaded on an aluminum foil ( Figure 5 ), and the negative electrode ( Figure 6 ).

[0074] S3. Power-on process: TDA3010 adjustable DC stable power supply is used as an external power supply to connect the positive electrode plate and the graphite rod anode, and the voltage is adjusted to 5V and the current to 0.3A; the positive electrode of the external power supply is connected to the graphite rod, and the negative electrode of the external power supply is connected to the positive electrode plate. The electrode clamp should be connected to the aluminum foil of the positive electrode plate to keep the circuit conductive; immerse the graphite rod and the positive electrode plate in 500mL of 1mol / L sodium sulfate solution electrolyte, turn on the external power switch, and power on for 10s. Bubbles are generated at the interface between the aluminum foil in the positive electrode plate and the positive active material on it, and the two are gradually separated.

[0075] S4. Washing and drying: The aluminum foil and positive electrode active material separated in S3 were rinsed with pure water, repeated 3 times to reduce residual impurities such as sodium sulfate; the rinsed aluminum foil and battery positive electrode active material were placed in an electric blast drying oven for 30 minutes at a temperature of 105°C; the separated aluminum foil ( Figure 7 ) and positive electrode active materials ( Figure 8 ), and weigh both.

[0076] Test the separation and recovery effect of positive electrode active materials and aluminum foil:

[0077] refer to Fig. 9 , XRD (X-ray diffraction) characterization shows that the aluminum foil and the positive electrode active material are well separated and there is no residue; reference Fig.10 , ICP-OES (inductively coupled plasma emission spectroscopy) test shows that the separated aluminum foil does not contain positive electrode active materials, and there is no aluminum residue on the separated positive electrode active materials, and the separation efficiency reaches >99%; reference Fig.11 and Fig.12 , XPS (X-ray photoelectron spectroscopy) was used to characterize the separated aluminum foil and positive electrode active material, indicating that the two were well separated and there was no residue; reference Fig.13 , XPS was used to characterize the separated positive electrode active material, and it was found that it was consistent with that before separation, proving that the positive electrode active material maintained its original properties during the separation process; Fig.14 , the metal elements in the solution were measured by ICP-OES, and it was calculated that the loss rate of the metal positive electrode active material was low, with Li loss of about 2% and Fe and Mn losses less than 0.5%.

[0078] Example 2

[0079] Example 2 is consistent with Example 1, except that the negative electrode sheet obtained by disassembling the cylindrical lithium battery is connected to an external power source, and the negative electrode sheet is recycled to obtain the separated copper foil ( Fig.15 ) and negative electrode active materials ( Fig.16 )

[0080] Characterize the separation and recovery effect of negative electrode active materials and copper foil;

[0081] X-ray diffraction characterization of negative electrode active materials and copper foil. Fig.17 ,XRD characterization shows that the copper foil and the negative electrode active material are well separated without any residue.

[0082] Example 3

[0083] S1. Discharge treatment: Using the salt solution immersion method, immerse the intact and undamaged waste LFP soft-pack batteries in 200 mL of 10% sodium chloride solution by mass for 24 hours.

[0084] S2. Disassembly: The cylindrical lithium battery after discharge treatment is disassembled and the battery shell is removed; the disassembled positive electrode sheet, negative electrode sheet and separator are placed in a fume hood for 6 hours to obtain the positive electrode active material ( Fig.18 ), and the negative electrode ( Fig.19 ).

[0085] S3. Power-on treatment: TDA3010 adjustable DC stable power supply is used as an external power supply to connect the positive electrode plate and the graphite rod anode, and the voltage is adjusted to 3V; the positive electrode of the external power supply is connected to the graphite rod, and the negative electrode of the external power supply is connected to the positive electrode plate. The electrode clamp should be connected to the aluminum foil of the positive electrode plate to keep the circuit conductive; immerse the graphite rod and the positive electrode plate in 500mL of 0.5mol / L sodium sulfate solution electrolyte, turn on the external power switch, and power on for 100s. Bubbles are generated at the interface between the aluminum foil in the positive electrode plate and the positive active material on it, and the two are gradually separated.

[0086] S4. Washing and drying: The aluminum foil and positive electrode active material separated in S3 were rinsed with pure water, repeated 3 times to reduce residual impurities such as sodium sulfate; the rinsed aluminum foil and battery positive electrode active material were placed in an electric blast drying oven for 30 minutes at a temperature of 105°C; the separated aluminum foil ( Fig. 20 ) and positive electrode active materials ( Fig.21 ). Weigh both.

[0087] Characterize the separation and recovery effect of positive electrode active materials and aluminum foil;

[0088] See also Fig. 20 and Fig.21 ,XRD characterization shows that the aluminum foil and the positive electrode active material are well separated without any residue.

[0089] refer to Fig. 22, ICP-OES test shows that the separated aluminum foil does not contain positive electrode active materials, and there is no aluminum residue on the separated positive electrode active materials, and the separation efficiency reaches >99%; Reference Fig.23 , ICP-OES was further used to measure the metal elements in the solution, and it was calculated that the loss rate of the metal positive electrode active material was low, with Li loss of about 2% and Fe loss of less than 0.1%.

[0090] Example 4

[0091] Example 4 is consistent with Example 3, except that the negative electrode sheet obtained by disassembling the LFP soft-pack battery is connected to an external power supply, and the negative electrode sheet is recycled to obtain the separated copper foil ( Fig.24 ) and negative electrode active materials ( Fig.25 ).

[0092] Example 5

[0093] S1. Discharge treatment: Using the salt solution immersion method, immerse the intact and undamaged waste NCM soft-pack batteries in 200 mL of 10% sodium chloride solution by mass for 24 hours.

[0094] S2. Disassembly: The cylindrical lithium battery after discharge treatment is disassembled and the battery shell is removed; the disassembled positive electrode sheet, negative electrode sheet and separator are placed in a fume hood for 6 hours to obtain the positive electrode active material ( Fig.26 ), and the negative electrode ( Fig. 27 ).

[0095] S3. Power-on treatment: TDA3010 adjustable DC stable power supply is used as an external power supply to connect the positive electrode plate and the graphite rod anode, and the voltage is adjusted to 6V; the positive electrode of the external power supply is connected to the graphite rod, and the negative electrode of the external power supply is connected to the positive electrode plate. The electrode clamp should be connected to the aluminum foil of the positive electrode plate to keep the circuit conductive; immerse the graphite rod and the positive electrode plate in 500mL of 1.4mol / L sodium sulfate solution electrolyte, turn on the external power switch, and power on for 200s. Bubbles are generated at the interface between the aluminum foil in the positive electrode plate and the positive active material on it, and the two are gradually separated.

[0096] S4. Washing and drying: The aluminum foil and positive electrode active material separated in S3 were rinsed with pure water, repeated 3 times to reduce residual impurities such as sodium sulfate; the rinsed aluminum foil and battery positive electrode active material were placed in an electric blast drying oven for 30 minutes at a temperature of 105°C; the separated aluminum foil ( Fig.28 ) and positive electrode active materials ( Fig.29 ). Weigh both.

[0097] Characterize the separation and recovery effect of positive electrode active materials and aluminum foil;

[0098] See also Fig.28 and Fig.29 ,XRD characterization shows that the aluminum foil and the positive electrode active material are well separated without any residue.

[0099] See also Fig.30 , ICP-OES test shows that the separated aluminum foil does not contain positive electrode active materials, and there is no aluminum residue on the separated positive electrode active materials, and the separation efficiency reaches >99%; Reference Fig.31 , ICP-OES was further used to measure the metal elements in the solution, and it was calculated that the loss rate of the metal positive electrode active materials was low, among which Li lost about 5%, and Mn, Co and Ni lost less than 0.5%.

[0100] Example 6

[0101] Example 6 is consistent with Example 5, except that the negative electrode sheet obtained by disassembling the NCM soft-pack battery is connected to an external power supply, and the negative electrode sheet is recycled to obtain the separated copper foil ( Fig.32 ) and negative electrode active materials ( Fig.33 ).

[0102] In the present application, the writing order of each step does not mean a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic. If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) can be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0103] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for recycling lithium battery pole pieces, characterized in that: include: Connecting a lithium battery pole piece placed in an electrolytic cell to a negative electrode of an external power source, wherein the lithium battery pole piece includes a current collector and an active material layer located on at least one side of the current collector; Connecting the anode placed in the electrolytic cell to the positive electrode of the external power supply; The electrolytic cell is subjected to an energizing treatment at a voltage of 2V-6V, so that the active material layer is separated from the current collector.

2. The method according to claim 1, characterized in that During the power-on treatment, the current density on the lithium battery electrode is 0.001A / cm 2 -0.005A / cm 2 .

3. The method according to claim 1, characterized in that The power-on treatment time is 5s-200s.

4. The method according to claim 1, characterized in that: The solute of the electrolyte in the electrolytic cell includes at least one of potassium nitrate, sodium nitrate, potassium sulfate and sodium sulfate.

5. The method according to claim 4, characterized in that The concentration of the electrolyte is 0.5 mol / L-1.4 mol / L.

6. The method according to any one of claims 1 to 5, characterized in that: Further including: The separated active material layer is washed with water and dried.

7. The method according to any one of claims 1 to 5, characterized in that: The lithium battery pole piece includes a positive pole piece and / or a negative pole piece, the positive pole piece includes a positive current collector and a positive active material layer located on at least one side of the positive current collector, the positive active material layer includes a positive active material, and the positive active material includes at least one of a nickel-cobalt-manganese ternary material, a nickel-cobalt-aluminum ternary material, lithium iron phosphate, lithium cobalt oxide, and lithium manganese oxide.

8. A method for recycling lithium batteries, characterized in that: include: Disassembling the lithium battery to obtain the lithium battery pole piece; The lithium battery pole piece is recycled using the method described in any one of claims 1 to 7.

9. The method according to claim 8, characterized in that Before disassembling the lithium battery, the method further includes: discharging the lithium battery, wherein the discharging treatment includes at least one of a chemical solution immersion method and an external resistor discharge method.

10. An active material, characterized in that The active material is recovered by the method according to any one of claims 1 to 8.

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