A method for separating and recycling a positive electrode material and a current collector of a waste lithium ion battery

Abstract

The application discloses a separation and recovery method of a positive electrode material and a current collector of a waste lithium ion battery. The separation and recovery method comprises the following steps: providing a positive electrode sheet of the waste lithium ion battery; contacting the positive electrode sheet with a dissolving solution containing a dissolving agent to perform a slightly soluble reaction to obtain a slightly soluble electrode sheet, wherein the dissolving agent comprises a surfactant and an auxiliary agent; drying the slightly soluble electrode sheet at a selected temperature; and mechanically separating the current collector and the positive electrode material on the slightly soluble electrode sheet. The separation and recovery method provided by the application can controllably slightly dissolve the surface of elemental aluminum, form a specific slightly soluble structure, and further reduce the adhesion between the positive electrode material and the elemental aluminum by using the principle of thermal expansion and cold contraction through low-temperature drying treatment. Finally, the current collector and the positive electrode material with extremely high separation efficiency can be obtained through mechanical separation. The method meets the environmental protection requirements, the process flow is simple and easy to implement, and is beneficial to large-scale application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource recycling, and particularly relates to a separation and recovery method of waste lithium ion battery positive electrode material and current collector. BACKGROUND

[0002] Lithium ion batteries are widely used in consumer electronics, electric vehicles, industrial energy storage and other fields due to their many advantages. In recent years, China's new energy industry has developed rapidly, and the market size of lithium ion batteries has expanded rapidly. In particular, the booming development of the new energy vehicle industry has led to an increasing demand for and production of power lithium ion batteries. After being used for a certain period of time, lithium ion batteries enter the stage of being discarded. Waste lithium ion batteries are known as high-grade "metal mines", and the positive electrode material contains a large amount of nickel, cobalt, manganese, lithium, aluminum and other high-value metal elements, with an element content much higher than that of metal ores in nature, and has a very high recycling value. However, improper handling can cause great harm to the environment. Therefore, waste lithium ion batteries have the dual attributes of resource value and environmental harm. The existing mainstream recycling process of waste lithium ion battery positive electrode material mainly includes three parts: pretreatment, valuable metal leaching, and valuable metal separation or resynthesis. However, most studies focus on the latter two parts, ignoring the pretreatment process. In the manufacturing process of lithium ion batteries, a binder (generally PVDF) is added to bond the positive electrode material to the current collector. In the recycling process, how to green and efficiently separate the positive electrode powder from the aluminum foil current collector is a key link in the pretreatment stage, which directly affects the recycling quality and recovery rate of the positive electrode powder.

[0003] The existing patent technology mainly uses crushing and screening, heat treatment, organic solvent treatment, and alkali dissolution to realize the separation of waste lithium ion battery positive electrode material and current collector.

[0004] For example, Chinese patent (CN109119714A) first separates the black powder from the positive electrode sheet obtained by discharging and disassembling waste lithium ion batteries through crushing and screening, then mixes the black powder with a polar solvent and performs magnetic separation, separates the magnetic material from the polar solvent to obtain the electrode material, and returns the non-magnetic material to the first step at least once before separating the mixture of carbon black and binder from the polar solvent. The separation efficiency of aluminum foil and positive electrode material is very low during the initial crushing, which causes a large loss. The positive electrode material has almost no magnetism when the valence reduction is not completed, and the separation of organic components and electrode material cannot be completely realized by magnetic separation, resulting in low recovery rate of electrode material in the overall recovery process. Chinese patent (CN10108336442A) first uses heating treatment to pretreat the positive electrode sheet of waste lithium battery, then stirs in an organic solution, and finally separates the aluminum foil and electrode material through processes such as centrifugal separation, drying and screening. The final separation efficiency reaches more than 95%, and the purity of aluminum foil reaches more than 99%. However, the method produces toxic and harmful gases during pretreatment, and the overall process flow is long and the processing capacity is limited. Chinese patent (CN111411233A) crushes the positive electrode sheet of waste lithium ion battery after drying, sets an aluminum plate at the top of the vacuum calcination furnace and circulates the condensed water, spreads the positive electrode sheet powder on the bottom of the calcination furnace, and calcines for 3h. The current collector condenses on the top aluminum plate, and the bottom residue is the positive electrode material. The positive electrode material obtained by this method has high purity, but the processing temperature and pressure are high, the equipment requirements are high, the overall process energy consumption is high, and the processing cost is increased. Chinese patent (CN111326817A) washes the positive electrode sheet of waste lithium ion battery and then immerses it in a high-concentration alkali solution to dissolve the aluminum foil to separate the positive electrode material. This method can efficiently separate the positive electrode material and aluminum foil, but the aluminum foil loss is large, the strong alkali solution can corrode the equipment and is harmful to the human body, the tail liquid treatment is difficult, and it does not meet the green and environmental protection requirements. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for separating and recovering positive electrode material and current collector from waste lithium ion batteries.

[0006] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application comprises:

[0007] The present application provides a method for separating and recovering positive electrode material and current collector from waste lithium ion batteries, comprising:

[0008] A positive electrode sheet of a waste lithium ion battery is provided, which comprises a current collector and a positive electrode material loaded on the surface of the current collector, and the current collector at least comprises elemental aluminum in contact with the positive electrode material.

[0009] contacting the waste lithium ion battery positive plate with a dissolving solution containing a dissolving agent, and performing a micro-dissolution reaction to obtain a micro-dissolution positive plate, the dissolving agent comprising a surfactant and an auxiliary agent capable of dissolving elemental aluminum;

[0010] drying the micro-dissolution positive plate at a selected temperature;

[0011] mechanically separating the current collector and the positive material on the micro-dissolution positive plate.

[0012] Compared with the prior art, the beneficial effects of the present application at least include:

[0013] 1. The separation and recovery method of the waste lithium ion battery positive material and the current collector provided by the present application can controllably micro-dissolve the surface of elemental aluminum, form a specific micro-dissolution structure, further reduce the adhesion between the positive material and the elemental aluminum by using the principle of thermal expansion and cold contraction through low-temperature drying treatment, and finally obtain the current collector and the positive material with extremely high separation efficiency through mechanical separation.

[0014] 2. The separation and recovery method provided by the present application does not use strong acid, strong base and toxic and harmful organic solvents, has less harm to the human body, does not produce wastewater, has no pollution, and the organic components in the positive material completely enter the separated material without decomposition to produce harmful gases in the treatment process, which meets the environmental protection requirements.

[0015] 3. The separation and recovery method provided by the present application has a simple process flow. The entire process flow is composed of a simple micro-dissolution reaction, low-temperature drying and mechanical separation, and belongs to a simple and efficient separation and recovery process.

[0016] 4. The separation and recovery method provided by the present application has low process operation cost, large processing capacity and good industrial application potential.

[0017] The above description is only a summary of the technical solutions of the present application. In order to enable those skilled in the art to more clearly understand the technical means of the present application and can be implemented according to the content of the description, the following describes the preferred embodiments of the present application with reference to the detailed description of the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a process flow schematic diagram of the separation and recovery method of the waste lithium ion battery positive electrode provided by a typical embodiment of the present application;

[0019] Figure 2a is an electron microscope photo of the surface morphology of the positive current collector before the micro-dissolution reaction provided by a typical embodiment of the present application;

[0020] Figure 2bIt is a typical embodiment of the present application to provide a micro-soluble reaction after the positive electrode current collector surface morphology electron microscope photo. DETAILED DESCRIPTION

[0021] In view of the deficiencies in the prior art, the present inventors have long studied and practiced to come up with the technical solution of the present application. The technical solution, its implementation process and principles will be further explained as follows.

[0022] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, therefore, the scope of protection of the present application is not limited by the specific embodiments disclosed below.

[0023] The present inventors have found through long-term practice that the existing lithium ion battery positive electrode material separation method mainly has the following problems: (1) The process is complicated, and impurities (metal debris) are introduced, which reduces the purity of the positive electrode material. (2) The organic components of the binder cannot be reasonably disposed. The existing technology mainly uses high-temperature heat to pretreat, and in this process, the combustion of organic components will produce harmful gas hydrogen fluoride, which will corrode the equipment and harm human health. (3) The cost of the reagent used is high, which will corrode the equipment and human skin. (4) The process flow is complex, and the processing capacity is limited.

[0024] In view of the shortcomings of the prior art, the dissolving agent used in the embodiments of the present application has low cost, small environmental impact, short process flow, and can be recycled. The separation and recovery method provided in the examples of the present application can generally be as follows: the positive electrode sheet is obtained by disassembling the discharged waste lithium ion battery, the positive electrode sheet is soaked in a certain concentration of dissolving agent for a certain time, the positive electrode sheet is dried at low temperature after filtration, and then ultrasonic vibration screening is carried out, and the undersize material obtained is the positive electrode material, and in some examples, the state of the positive electrode material is black powder, and the remaining oversize material is the current collector, such as aluminum foil. The obtained aluminum foil has high purity and can be directly recycled, and the positive electrode black powder has almost no loss and can be further recovered for valuable metals.

[0025] For specific examples, please refer to Figure 1 The embodiments of the present application provide a separation and recovery method for positive electrode material and current collector of waste lithium ion battery, which comprises the following steps:

[0026] A positive electrode sheet of a waste lithium ion battery is provided, which comprises a current collector and a positive electrode material loaded on the surface of the current collector, and the current collector at least comprises elemental aluminum in contact with the positive electrode material.

[0027] Contacting the waste old lithium ion battery positive plate with a dissolving solution containing a dissolving agent, carrying out a micro-dissolution reaction to obtain a micro-dissolution positive plate, the dissolving agent including a surfactant and an auxiliary agent capable of dissolving elemental aluminum.

[0028] Drying the micro-dissolution positive plate at a selected temperature.

[0029] Mechanically separating the current collector and the positive electrode material on the micro-dissolution positive plate.

[0030] As a specific application example, the above technical solution can be implemented by the following specific steps:

[0031] The waste old lithium ion battery positive electrode (including lithium cobaltate, lithium manganate, lithium iron phosphate, nickel cobalt manganese (ternary) and other types of batteries) or the positive electrode scraps generated in the battery production process is used as raw material. First, the positive plate is obtained by disassembling the fully discharged waste old lithium ion battery, and the positive plate is cut into small pieces and soaked in a certain concentration of dissolving agent for a certain time. The surface dissolving agent is filtered and washed with deionized water, and then placed in an oven for low temperature drying for a period of time. Finally, the positive plate is mixed with grinding medium in a certain proportion, and then placed in a standard sieve for a certain time of ultrasonic vibration screening. The current collector aluminum foil is obtained after the sieve and the grinding medium are separated, and the black powder formed by the positive electrode material is obtained. The dissolving agent and the washing water are recycled during the whole process.

[0032] The waste old lithium ion battery positive electrode is mainly derived from waste electronic products, waste power cars, and positive electrode production process scraps in the field. The positive plate cutting process is to cut the positive plate into 1-25 cm 2 The current collector can be a simple aluminum foil, a multi-layer composite metal foil, or a composite foil of inorganic material and aluminum, such as copper-aluminum composite foil, etc. Of course, the aluminum layer should be close to the above electrode material.

[0033] Based on the above exemplary technical solutions, the application provides a separation and recovery method of waste lithium ion battery positive electrode material and current collector, the waste lithium ion battery positive electrode comprises positive electrode sheets obtained by disassembling waste lithium ion batteries or positive electrode corner materials generated in a coating process of battery positive electrode production, and different concentrations of dissolving agents are used for soaking treatment, and after filtration, washing and low-temperature drying, ultrasonic vibration screening is performed, so that the positive electrode material and the current collector such as aluminum foil are completely separated and recovered. The purity of the obtained aluminum foil is high, the recovery rate is greater than 95%, and the recovered positive electrode material does not contain metal debris, which is beneficial to subsequent recycling. The obtained positive electrode material can be reused for manufacturing positive electrode material after subsequent treatment of recovering valuable metals or repairing, and the aluminum foil can be directly used for manufacturing related aluminum products. The whole process includes three parts of interface micro-etching, low-temperature drying and vibration screening, the separation reagent can be recycled, and belongs to a mild surface interface modification reagent. The separation efficiency of the positive electrode material and the aluminum foil current collector is high, no pollutants are generated, and the treatment amount is less limited by the liquid-solid ratio, which is a green short-process separation process and is suitable for industrial application.

[0034] In summary, the advantages of the separation and recovery method provided by the embodiments of the application can be mainly summarized as follows: (1) high separation efficiency: the principle of the dissolving agent is to controllably dissolve the surface of the current collector, especially the aluminum foil, during soaking, the low-temperature drying treatment further reduces the adhesion between the positive electrode material and the aluminum foil by using the principle of thermal expansion and cold contraction, and finally the external force is applied through ultrasonic vibration screening, so that the above processes work together to finally realize the high-efficiency separation of the positive electrode material. (2) excellent environmental protection: the above technical solution does not use strong acid, strong base and toxic and harmful organic solvents, has less harm to human body, does not produce wastewater, has no pollution, and the organic components in the positive electrode material finally enter the separated material, for example, the black powder, and no harmful gas is generated in the treatment process due to the decomposition of the organic components, which meets the environmental protection requirements. (3) simple process flow: the whole process flow can be composed of three parts of soaking, drying and ultrasonic vibration screening, and belongs to a simple and efficient separation and recovery process. (4) good industrial application potential: the above technical solution has low process operation cost, large treatment capacity and is easy to be industrialized.

[0035] Figure 2a An electron microscope picture of a current collector aluminum foil before micro-dissolution treatment is shown, Figure 2b A surface electron microscope picture after micro-dissolution treatment is shown, in some embodiments, the surface of the current collector in contact with the positive electrode material in the micro-dissolution electrode sheet forms a plurality of corrosion pits.

[0036] In some embodiments, the diameter of the corrosion pits can be preferably 10-100 nm.

[0037] The formation of the above-mentioned corrosion pits reduces the contact area between the current collector and the positive electrode material on one hand, and reduces the binding force between the two, and on the other hand, some gas is formed or accommodated in the holes, which, in combination with the subsequent drying treatment under certain conditions, the expansion of these gases is more conducive to the disintegration of the positive electrode material, and in combination with the mechanical separation method such as ultrasonic vibration screening, the current collector and the positive electrode material can be separated very efficiently.

[0038] The size and density of the corrosion pits in the surface structure of the above-mentioned slightly soluble current collector are too large, which will cause excessive corrosion of the current collector and waste of current collector material, and if the size and density of the corrosion pits are too small, it may not be conducive to the efficient separation by using the above-mentioned gas expansion effect.

[0039] In some embodiments, the surface active agent is preferably selected from strong base weak acid salt, preferably any one or a combination of two or more of alkyl ammonium salt, alkyl imidazoline salt, ethoxylated ammonium compound and quaternary ammonium salt; in addition to the above-mentioned alkyl ammonium salt, alkyl imidazoline salt, ethoxylated ammonium, quaternary ammonium salt and the like, other surface active agent salts of the same type with cleaning effect, especially cationic surfactants can be replaced.

[0040] In some embodiments, the surface active agent can include any one or a combination of two or more of octadecyl trimethyl ammonium chloride, bis-alkyl dimethyl ammonium chloride, cocamide propyl betaine and ammonium oxide.

[0041] In some embodiments, the auxiliary agent can include any one or a combination of two or more of sodium carbonate, sodium bicarbonate, potassium silicate, calcium silicate, sodium silicate, potassium carbonate and potassium bicarbonate.

[0042] In some embodiments, the molar ratio of the surface active agent to the auxiliary agent is preferably 1:0.01-1:0.1.

[0043] In some embodiments, the mass fraction of the surface active agent in the dissolution solution is preferably 1-9%.

[0044] In some embodiments, the temperature of the slightly soluble reaction is preferably 20-95°C, and the time is preferably 0.5-24h.

[0045] In some embodiments, the selected temperature is preferably 30-200°C, and the drying time is preferably 0.5-24h.

[0046] In some embodiments, the mechanical separation can include ultrasonic vibration screening.

[0047] In some embodiments, the ultrasonic vibration screening can specifically include the following steps:

[0048] The micro-solubility cathode sheet after drying treatment is mixed with grinding medium and placed in a screen to apply ultrasonic vibration to separate the current collector from the positive electrode material, and the current collector is obtained from the oversize and the positive electrode material is obtained from the undersize.

[0049] In some embodiments, the grinding medium can include metal balls and / or ceramic balls.

[0050] In some embodiments, the diameter of the grinding medium can preferably be 1.5-5 mm.

[0051] In some embodiments, the mesh size of the screen can preferably be 10-60 mesh.

[0052] In some embodiments, the mass ratio of the grinding medium to the micro-solubility cathode sheet can preferably be 7:1-15:1.

[0053] In some embodiments, the power of the ultrasonic vibration screening can preferably be 50-200 W, and the time can preferably be 5-30 min.

[0054] The above illustrates a way of ultrasonic vibration screening, based on the same principle, mechanical separation and screening can also be carried out in steps, for example, a device similar to a vibrating disc or a polishing machine can be used to separate the positive electrode material from the current collector by mechanical stirring, shaking or ultrasonic vibration, and then the separated mixture is transferred to a screening device for screening. The advantage of the preferred one-step ultrasonic vibration screening of the embodiments of the present application is that the step of mechanical separation is simplified, which is beneficial for large-scale production.

[0055] In some embodiments, the waste lithium ion battery cathode sheet can be preferably cut into a sheet shape of 1-25 cm 2 .

[0056] In some embodiments, the waste lithium ion battery cathode sheet can include a positive electrode from disassembled lithium ion batteries and / or positive electrode waste generated during the production process of lithium ion batteries.

[0057] In some embodiments, the dissolving agent and the cleaning wastewater generated during the separation and recovery process can be recycled.

[0058] In the present application, the type and ratio of the dissolving agent are critical. After the positive plate is treated by the dissolving agent, the surface of the current collector aluminum foil is only slightly dissolved, and no reaction occurs with the positive material. The loss of the aluminum foil is small, and the phase characteristics do not change. The whole process is simple, and no high-temperature heating, strong acid, strong base, and organic solvent are used. Liquid recycling is used, and no pollutants are generated. The recovery cost is reduced, and the environmental pollution and harm to the human body are reduced. The adhesion between the electrode material and the current collector is reduced by the interaction of the slight dissolution of the dissolving agent and low-temperature drying, so that the separation of the two is realized. Therefore, the treatment capacity of the positive plate is not limited by the liquid-solid ratio, and has the potential for industrial application.

[0059] The technical solutions of the present application are further described in detail below by several embodiments in conjunction with the accompanying drawings. However, the selected embodiments are only used to illustrate the present application, and do not limit the scope of the present application.

[0060] Unless otherwise specified, the various raw materials and reagents in the following examples are commercially available, and the solvents and cleaning liquids involved are water.

[0061] Example 1

[0062] This example illustrates a process of a separation and recovery method of waste lithium ion battery positive material and current collector, as shown below:

[0063] The waste lithium cobalt oxide battery positive plate is used as raw material, a dissolving solution is formed by dissolving 7% by mass of surfactant octadecyl trimethyl ammonium chloride and 1% by mole fraction of sodium carbonate and 1% by mole fraction of sodium silicate, the soaking temperature is 30℃, and the soaking time is 8h. Among them, the liquid-solid ratio of the dissolving solution to the waste lithium cobalt oxide battery positive plate is 4L / kg.

[0064] After filtration, the positive plate is washed with an aqueous solution and then dried at 150℃ for 4h.

[0065] After drying, the positive plate is mixed with corundum grinding medium with a diameter of 2mm at a ball-to-material mass ratio of 10:1, and then put into a 60-mesh ultrasonic vibration screen for 30min.

[0066] After the final sieve residue is separated from the grinding medium, the aluminum foil is obtained, and the sieve residue is black powder composed of waste positive material.

[0067] In this example, the separation efficiency of the positive material and the aluminum foil is greater than 95%. The obtained positive black powder material is treated by subsequent treatment to recover valuable metals or is repaired and then used to manufacture positive materials. The aluminum foil can be directly used to manufacture related aluminum products.

[0068] Example 2

[0069] The embodiment illustrates a process of a separation and recovery method of a positive electrode material and a current collector of a waste lithium ion battery, and is specifically as follows:

[0070] The waste ternary battery positive electrode sheet is used as a raw material, a surfactant octadecyl trimethyl ammonium chloride with a mass fraction of 7% and sodium bicarbonate with a molar fraction of 1% of the surfactant, potassium carbonate with a molar fraction of 1% of the surfactant, and calcium silicate with a molar fraction of 1% of the surfactant are mixed to form a dissolving solution, the soaking temperature is 30°C, and the soaking time is 4 h. The liquid-solid ratio of the dissolving solution to the waste lithium cobalt oxide battery positive electrode sheet is 8 L / kg.

[0071] The positive electrode sheet after filtration is washed by an aqueous solution and then dried at 150°C for 3 h.

[0072] The dried positive electrode sheet is mixed with corundum grinding medium with a diameter of 2 mm at a ball-material ratio of 10:1 in mass, and then put into a 60-mesh ultrasonic vibrating screen for screening for 20 min.

[0073] The final sieve residue is separated from the grinding medium to obtain an aluminum foil, and the sieve underfall is a black powder composed of waste positive electrode materials.

[0074] In the embodiment, the separation efficiency of the positive electrode material and the aluminum foil is greater than 95%. The obtained positive electrode black powder material is subjected to subsequent treatment to recover valuable metals or is repaired and then used for manufacturing a positive electrode material, and the aluminum foil can be directly used for manufacturing related aluminum products.

[0075] Embodiment 3

[0076] The embodiment illustrates a process of a separation and recovery method of a positive electrode material and a current collector of a waste lithium ion battery, and is specifically as follows:

[0077] The waste lithium iron phosphate battery positive electrode sheet is used as a raw material, a surfactant octadecyl trimethyl ammonium chloride with a mass fraction of 5% and ammonium oxide with a molar ratio of 1:1 are mixed, and then 1% of a molar fraction of potassium silicate, 1% of a molar fraction of sodium carbonate of the surfactant are added to form a dissolving solution, the soaking temperature is 30°C, and the soaking time is 6 h. The liquid-solid ratio of the dissolving solution to the waste lithium cobalt oxide battery positive electrode sheet is 5 L / kg.

[0078] The positive electrode sheet after filtration is washed by an aqueous solution and then dried at 150°C for 3 h.

[0079] The dried positive electrode sheet is mixed with corundum grinding medium with a diameter of 2 mm at a ball-material ratio of 7:1 in mass, and then put into a 60-mesh ultrasonic vibrating screen for screening for 10 min.

[0080] The final sieve residue is separated from the grinding medium to obtain an aluminum foil, and the sieve underfall is a black powder composed of waste positive electrode materials.

[0081] In this embodiment, the separation efficiency of the positive electrode material and the aluminum foil is greater than 95%. The obtained positive electrode black powder material is recycled for valuable metals or repaired and reused for manufacturing positive electrode materials, and the aluminum foil can be directly used for manufacturing related aluminum products.

[0082] Example 4

[0083] This embodiment illustrates a process of a separation and recovery method of a waste lithium ion battery positive electrode material and a current collector, as shown below:

[0084] The waste lithium cobalt oxide battery positive electrode sheet is used as raw material, a surfactant octadecyl trimethyl ammonium chloride with a mass fraction of 5% and a sodium carbonate solution with a molar fraction of 1% and a potassium bicarbonate solution with a molar fraction of 1% are used to form a dissolving solution, the soaking temperature is 30°C, and the soaking time is 3h. Among them, the liquid-solid ratio of the dissolving solution to the waste lithium cobalt oxide battery positive electrode sheet is 7L / kg.

[0085] After filtration, the positive electrode sheet is washed with an aqueous solution and then dried at 150°C for 2h.

[0086] The dried positive electrode sheet is mixed with corundum grinding medium with a diameter of 2mm at a ball-to-material ratio of 7:1, and then put into a 60-mesh ultrasonic vibration screen for 10min.

[0087] After the final sieve and the grinding medium are separated, the aluminum foil is obtained, and the sieve is the black powder composed of the waste positive electrode material.

[0088] In this embodiment, the separation efficiency of the positive electrode material and the aluminum foil is greater than 95%. The obtained positive electrode black powder material is recycled for valuable metals or repaired and reused for manufacturing positive electrode materials, and the aluminum foil can be directly used for manufacturing related aluminum products.

[0089] Example 5

[0090] This embodiment illustrates a process of a separation and recovery method of a waste lithium ion battery positive electrode material and a current collector, which is basically the same as that of Example 1, and the difference is only that:

[0091] The sodium carbonate and the sodium silicate each account for 5mol% of the surfactant, the soaking temperature is 95°C, and the soaking time is half an hour.

[0092] After filtration, the positive electrode sheet is washed with an aqueous solution and then dried at 30°C for 24h.

[0093] The dried positive electrode sheet is mixed with corundum grinding medium with a diameter of 5mm at a ball-to-material ratio of 15:1, and then put into a 10-mesh ultrasonic vibration screen for 30min.

[0094] In the embodiment, the separation efficiency of the positive electrode material and the aluminum foil is greater than 95%. The obtained positive electrode black powder material is recycled for valuable metals or is repaired and reused for manufacturing the positive electrode material, and the aluminum foil can be directly used for manufacturing related aluminum products.

[0095] Embodiment 6

[0096] The embodiment exemplifies a process of a separation and recovery method of waste lithium ion battery positive electrode material and current collector, which is basically the same as that in Embodiment 1, and the difference is only that:

[0097] The sodium carbonate and the sodium silicate each account for 2 mol% of the surfactant, the soaking temperature is 20℃, and the soaking time is 24h.

[0098] After filtration, the positive electrode sheet is washed by an aqueous solution and is dried at 200℃ for half an hour.

[0099] After drying, the positive electrode sheet is mixed with corundum grinding medium with a diameter of 1.5mm at a ball-to-material ratio of 15:1, and is sieved in a 40-mesh ultrasonic vibration sieve for 5min.

[0100] In the embodiment, the separation efficiency of the positive electrode material and the aluminum foil is greater than 95%. The obtained positive electrode black powder material is recycled for valuable metals or is repaired and reused for manufacturing the positive electrode material, and the aluminum foil can be directly used for manufacturing related aluminum products.

[0101] Based on the technical concept of the present application and the optional range of materials and parameters, other embodiments can be obtained according to the above-mentioned embodiments, and a better separation effect, a more green and environmentally friendly and healthy separation process can be obtained.

[0102] Based on the above-mentioned embodiments, it can be clearly seen that the separation and recovery method of waste lithium ion battery positive electrode material and current collector provided by the embodiments of the present application can controllably dissolve the surface of elemental aluminum, form a specific micro-dissolution structure, further reduce the adhesion between the positive electrode material and the elemental aluminum by using the principle of thermal expansion and cold contraction through low-temperature drying treatment, and finally obtain the current collector and the positive electrode material with extremely high separation efficiency through mechanical separation; no strong acid, strong base and toxic and harmful organic solvents are used, the harm to the human body is small, no wastewater is produced, no pollution is caused, the organic components in the positive electrode material completely enter the separated material, no harmful gas is produced in the treatment process, and the environmental protection requirements are met; the whole process is composed of three parts of simple micro-dissolution reaction, low-temperature drying and mechanical separation, and belongs to a simple and efficient separation and recovery process.

[0103] It should be understood that the above-described embodiments are merely intended to illustrate the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for separating and recycling the positive electrode material and current collector of waste lithium-ion batteries, characterized in that, include: A waste lithium-ion battery positive electrode sheet is provided, the waste lithium-ion battery positive electrode sheet includes a current collector and a positive electrode material loaded on the surface of the current collector, the current collector includes at least elemental aluminum in contact with the positive electrode material; The waste lithium-ion battery positive electrode sheet is brought into contact with a solution containing a solvent to undergo a micro-dissolution reaction to obtain a micro-soluble electrode sheet. The solvent includes a surfactant and an auxiliary agent. The auxiliary agent is capable of dissolving elemental aluminum. The surfactant includes any one or a combination of two or more of alkyl ammonium salts, alkyl imidazoline salts, ethoxylated ammonium compounds, and quaternary ammonium salts. The auxiliary agent includes a strong base-weak acid salt. The molar ratio of the surfactant to the auxiliary agent is 1:0.01-1:0.

1. The mass fraction of the surfactant in the solution is 1-9%. The temperature of the micro-dissolution reaction is 20-95℃, and the time is 0.5-24h. Multiple corrosion pits are formed on the surface of the current collector in contact with the positive electrode material in the micro-soluble electrode sheet. The diameter of the corrosion pits is 10-100nm. The microsoluble electrode sheet is dried at a selected temperature; Mechanical separation of the current collector and positive electrode material on the micro-soluble electrode sheet.

2. The separation and recovery method according to claim 1, characterized in that, The surfactant includes any one or a combination of two or more of octadecyltrimethylammonium chloride, dialkyldimethylammonium chloride, cocamidopropyl betaine, and ammonium oxide. And / or, the auxiliary agent includes any one or a combination of two or more of sodium carbonate, sodium bicarbonate, potassium silicate, calcium silicate, sodium silicate, potassium carbonate, and potassium bicarbonate.

3. The separation and recovery method according to claim 1, characterized in that, The selected temperature is 30-200℃, and the drying time is 0.5-24h.

4. The separation and recovery method according to claim 1, characterized in that, The mechanical separation includes ultrasonic vibration screening.

5. The separation and recovery method according to claim 4, characterized in that, The ultrasonic vibration screening specifically includes: The dried micro-soluble electrode sheet is mixed with grinding media and placed in a sieve. Ultrasonic vibration is applied to separate the current collector from the positive electrode material. The current collector is obtained from the material on the sieve, and the positive electrode material is obtained from the material under the sieve.

6. The separation and recovery method according to claim 5, characterized in that, The grinding media include metal balls and / or ceramic balls.

7. The separation and recovery method according to claim 6, characterized in that, The diameter of the grinding media is 1.5-5mm; the mesh size of the sieve is 10-60 mesh; the mass ratio of the grinding media to the micro-soluble electrode is 7:1-15:1; the power of the ultrasonic vibration sieving is 50-200W, and the time is 5-30min.

8. The separation and recovery method according to claim 1, characterized in that, The waste lithium-ion battery positive electrode sheet is cut to 1-25cm. 2 Flake-like.

9. The separation and recovery method according to claim 8, characterized in that, The waste lithium-ion battery cathode sheet includes the cathode from the dismantling of lithium-ion batteries and / or cathode waste generated during the production process of lithium-ion batteries.

10. The separation and recovery method according to claim 1, characterized in that, The solvent and the cleaning wastewater generated during the separation and recovery process are recycled.

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