Method for recycling materials in waste batteries by means of full-chain integrated treatment

Abstract

Disclosed is a method for recycling materials in waste batteries by means of full-chain integrated treatment, relating to the technical field of battery recycling. The method comprises: grafting a positive electrode sheet and a separator connected to the positive electrode sheet in a waste battery, so that the separator and a positive electrode binder for the positive electrode sheet are cross-linked by means of a graft; swelling the grafted material to reduce the bonding force between the positive electrode binder and a positive electrode current collector in the positive electrode sheet; and under the action of an external force, separating the positive electrode current collector from a positive electrode active material to which the separator is bonded. By means of the method, the positive electrode active material and the current collector in the waste battery can be effectively separated, and then the separated materials can be recycled.

Description

A full-chain integrated recycling method for materials from waste batteries Technical Field

[0001] The present disclosure relates to the technical field of battery recycling, and in particular to a recycling method for processing materials in waste batteries in an integrated manner throughout the entire chain. Background Art

[0002] In recent years, the global lithium-ion battery industry has experienced rapid growth, with electric vehicles becoming a key future development direction. This has created significant development opportunities for power lithium-ion batteries. However, lithium-ion batteries have a limited lifespan, and their widespread use leads to a significant amount of waste. Recycling usable materials from waste batteries, such as valuable metals, not only alleviates resource constraints and creates economic value, but also addresses the environmental impact of waste batteries.

[0003] At present, the recycling method of used batteries mainly involves discharging and crushing the batteries, and then using flotation, magnetic separation, and wet chemical methods to separate the target valuable metals. As for some methods for separating the positive electrode material from the current collector, they mainly use two methods: removing the binder and dissolving the current collector. However, the method of removing the binder often requires high-temperature treatment, and the temperature control is relatively strict. It is not acceptable to use temperatures that are too high or too low. In addition, the combustion of organic matter during the treatment process will cause air pollution. The dissolution of the positive electrode current collector aluminum foil is usually carried out with alkali (the reaction equation can be referred to as follows: 2Al+2H2O+2NaOH=2NaAlO2+3H2↑). This process produces a large amount of gas, and the gas will bring out some alkali solution, which will cause certain harm to the environment and people.

[0004] In view of this, the present disclosure is proposed.

[0005] Summary of the Invention

[0006] The purpose of the present disclosure includes providing a full-chain integrated recycling method for processing materials in waste batteries. The method can at least effectively separate the positive electrode active material and the current collector in the waste batteries, and the separated materials can be further recycled. In addition, the method is simple to operate, the conditions are easy to control, and it is environmentally friendly and safe.

[0007] The present disclosure can be implemented as follows:

[0008] The present disclosure provides a recycling method for materials in waste batteries with a full-chain integrated process, comprising: grafting a positive electrode sheet and a separator connected to the positive electrode sheet in the waste battery so that the separator and the positive electrode binder of the positive electrode sheet are cross-linked through the grafted material; then swelling the grafted material to reduce the bonding force between the positive electrode binder and the positive electrode collector in the positive electrode sheet; and separating the positive electrode collector from the positive electrode active material bonded to the separator under the action of an external force.

[0009] In an optional embodiment, the used batteries are used lithium-ion batteries.

[0010] In an alternative embodiment, the separator is a polymer electrolyte membrane.

[0011] In an optional embodiment, the main component of the positive electrode binder is polyvinylidene fluoride.

[0012] In an optional embodiment, the positive electrode current collector is aluminum foil.

[0013] In an optional embodiment, the grafting treatment includes: mixing the grafting raw material with the positive electrode sheet in the waste battery and the separator connected to the positive electrode sheet and performing a grafting reaction; wherein the grafting raw material includes acrylic acid, a cross-linking agent and an initiator.

[0014] In an alternative embodiment, the cross-linking agent comprises dibenzoyl peroxide; and the initiator comprises dicumyl peroxide.

[0015] In an optional embodiment, the mass ratio of acrylic acid to dibenzoyl peroxide and dicumyl peroxide is (8-10):(1-3):(2-4).

[0016] In an alternative embodiment, the grafting raw material further comprises a solvent.

[0017] In an alternative embodiment, the solvent comprises n-propanol.

[0018] In an alternative embodiment, 8g-10g of acrylic acid, 1g-3g of dibenzoyl peroxide, and 2g-4g of dicumyl peroxide are used per 100g of solvent.

[0019] In an optional embodiment, the grafting reaction has at least one of the following characteristics:

[0020] Feature 1: The temperature of the grafting reaction is 60℃-80℃;

[0021] Feature 2: The grafting reaction time is 2h-6h;

[0022] Feature 3: The grafting reaction is carried out under constant temperature, closed and dry conditions.

[0023] In an optional embodiment, the swelling includes: soaking the grafted material in water.

[0024] In an optional embodiment, the soaking temperature is 20° C.-30° C.; and / or the soaking time is 18 h-24 h.

[0025] In an optional embodiment, before the grafting treatment, the method further includes: pre-treating the waste battery;

[0026] Pre-treatment includes removing the electrolyte and negative electrode from the used batteries.

[0027] In an optional embodiment, removing the electrolyte includes heating the inner core of the waste battery to volatilize and remove the electrolyte.

[0028] In an optional embodiment, the heating temperature is 140° C.-150° C.; and / or the heating time is 1 h-2 h.

[0029] In an optional embodiment, removing the negative electrode sheet includes: soaking the battery core from which the electrolyte has been removed in water to dissolve the negative electrode binder in the negative electrode sheet in the water, removing the negative electrode sheet and the negative electrode active material that has fallen off the negative electrode collector of the negative electrode sheet, and collecting the positive electrode sheet and the separator connected to the positive electrode sheet.

[0030] In an optional embodiment, the soaking time is 24h-48h.

[0031] In an alternative embodiment, the negative electrode current collector is copper foil.

[0032] In an optional embodiment, the pre-treatment further includes: modifying the positive electrode sheet and the separator connected to the positive electrode sheet.

[0033] In an optional embodiment, the modification process has at least one of the following characteristics:

[0034] Feature 1: The treatment reagent used in the modification treatment is a mixed solution of alkali and alcohol;

[0035] Feature 2: The temperature of the modification treatment is 50℃-80℃;

[0036] Feature 3: The modification treatment time is 30min-90min.

[0037] In an optional embodiment, the base includes at least one of KOH and NaOH; and / or the alcohol includes ethanol; and / or the mass ratio of the base to the alcohol is (1:100)-(10:100).

[0038] In an optional embodiment, the positive electrode current collector and the positive electrode active material bonded with the separator are separated by providing an external force through a negative pressure adsorption device.

[0039] In an optional embodiment, the negative pressure adsorption device includes a suction cup, which is used to be adsorbed on the surface of the positive electrode current collector and / or the separator to be separated so as to separate the positive electrode current collector and the separator under the action of negative pressure.

[0040] In an optional embodiment, the suction cup is connected to a gas circulation pipe.

[0041] In an optional embodiment, the surface of the suction cup has a suction hole, which is connected to the gas flow pipe.

[0042] In an optional embodiment, the negative pressure range is 500Pa-1000Pa.

[0043] In an optional embodiment, the separated positive electrode active material bound with the separator is pulverized, and the separator is removed by sorting to obtain the positive electrode active material.

[0044] The bonding between the positive electrode active material and the positive electrode current collector is mainly achieved by physical adsorption formed by the van der Waals force generated between the positive electrode binder and the positive electrode current collector. The present invention simultaneously performs grafting treatment on the positive electrode binder and the separator, so that the connection between the positive electrode active material and the separator is mainly tightly cross-linked by the graft formed between the positive electrode binder and the separator; by swelling the grafted material, the bonding force between the positive electrode binder and the positive electrode current collector is reduced, and the positive electrode current collector can be effectively separated from the positive electrode active material bonded with the separator under the action of external force. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0046] FIG1 is a schematic structural diagram of a negative pressure adsorption device in the present disclosure;

[0047] FIG2 is a schematic diagram of the structure of the suction cup in the negative pressure adsorption device of the present disclosure.

[0048] Icons: 11-first separator; 12-first positive electrode active material layer; 13-aluminum foil layer; 14-second positive electrode active material layer; 15-second separator; 20-suction cup; 21-first suction cup; 22-second suction cup; 23-suction hole. DETAILED DESCRIPTION

[0049] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0050] The following is a detailed description of the full-chain integrated recycling method for materials in waste batteries provided by the present invention.

[0051] The present disclosure proposes a full-chain integrated recycling method for materials in waste batteries, including: grafting treatment of the positive electrode sheet in the waste battery and the diaphragm connected to the positive electrode sheet (such as by bonding, etc.) to cross-link the diaphragm and the positive electrode binder of the positive electrode sheet through the grafted material, and then swelling the grafted material to reduce the bonding force between the positive electrode binder and the positive electrode collector in the positive electrode sheet, and separating the positive electrode collector from the positive electrode active material bonded with the diaphragm under the action of external force.

[0052] For reference, the above-mentioned waste batteries can be waste lithium-ion batteries (such as waste nickel-cobalt-manganese ternary lithium-ion batteries, lithium manganate batteries, lithium iron phosphate batteries or lithium cobalt oxide batteries, etc.), and the corresponding positive electrode active materials can exemplarily include LiNi x Co y Mn z O2 (x+y+z=1), LiMn2O4, LiFePO4, or LiCoO2. The positive electrode current collector can be aluminum foil. The binder used between the positive electrode active material and the positive electrode current collector primarily includes polyvinylidene fluoride (PVDF). The separator is a polymer electrolyte membrane, such as polyethylene (PE).

[0053] In the present disclosure, the grafting treatment includes: mixing the grafting raw materials with the positive electrode sheet in the waste battery and the separator connected to the positive electrode sheet and performing a grafting reaction; wherein the grafting raw materials include acrylic acid, a crosslinking agent and an initiator.

[0054] For reference, the crosslinking agent may include dibenzoyl peroxide, and the initiator may include dicumyl peroxide. By using the above crosslinking agent and initiator to initiate free radical polymerization, the hydroxyl groups in the acrylic acid are introduced into the molecular chains of PVDF and the diaphragm and a crosslinking reaction is carried out.

[0055] In some embodiments, the mass ratio of acrylic acid to dibenzoyl peroxide and dicumyl peroxide is (8-10):(1-3):(2-4), such as 8:1:2, 8:1:3, 8:1:4, 8:2:2, 8:2:3, 8:2:4, 8:3:2, 8:3:3, 8:3:4, 9:1:2, 9:1:3, 9:1:4, 9:2:2, 9:2:3, 9:2:4, 9:3:2, 9:3:3, 9:3:4, 10:1:2, 10:1:3, 10:1:4, 10:2:2, 10:2:3, 10:2:4, 10:3:2, 10:3:3 or 10:3:4, or any other value within the range of (8-10):(1-3):(2-4).

[0056] Too little or too much dibenzoyl peroxide will result in a reduced grafting rate. Excessive amounts of dicumyl peroxide will be detrimental to improving reaction efficiency, while excessive amounts of dicumyl peroxide can easily cause side reactions, leading to reduced stability of the graft copolymer.

[0057] Furthermore, the grafting raw material also includes a solvent. For example, the solvent may include n-propanol. In addition, it is not excluded that other solvents that can dissolve acrylic acid and the above-mentioned crosslinking agent and initiator may be used.

[0058] In some embodiments, per 100 g of solvent, 8 g-10 g (e.g., 8 g, 8.5 g, 9 g, 9.5 g, or 10 g, etc.) of acrylic acid, 1 g-3 g (e.g., 1 g, 1.5 g, 2 g, 2.5 g, or 3 g, etc.) of dibenzoyl peroxide, and 2 g-4 g (e.g., 2 g, 2.5 g, 3 g, 3.5 g, or 4 g, etc.) of dicumyl peroxide can be used.

[0059] In the present disclosure, the temperature of the grafting reaction may be 60°C-80°C, such as 60°C, 65°C, 70°C, 75°C or 80°C, or any other value within the range of 60°C-80°C.

[0060] If the temperature of the grafting reaction is lower than 60°C, the reaction efficiency is reduced and the grafting rate is affected; if the temperature of the grafting reaction is higher than 80°C, it is easy to cause side reactions and reduce the stability of the grafted copolymer.

[0061] The grafting reaction time can be 2 h to 6 h, such as 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h or 6 h, or any other value within the range of 2 h to 6 h.

[0062] If the grafting reaction time is shorter than 2 hours, it is not conducive to the full grafting cross-linking reaction, which reduces the bonding effect; if the grafting reaction time is longer than 6 hours, side reactions are likely to occur, resulting in reduced stability of the graft copolymer.

[0063] The grafting reaction can be carried out under constant temperature, sealed and dry conditions to prevent solvent volatilization.

[0064] Continuing from the above, the principles of the above-mentioned grafting reaction include: primary free radicals are generated by initiators, and the primary free radicals further capture hydrogen atoms on the main chains of PVDF and diaphragms (mainly composed of PE) to form PVDF macromolecular free radicals and PE macromolecular free radicals. The PVDF macromolecular free radicals and PE macromolecular free radicals then undergo grafting copolymerization with the added monomers. At the same time, the coupling reaction between the PVDF macromolecular free radicals and the PE macromolecular free radicals will lead to branching and cross-linking of their molecular chains.

[0065] By simultaneously grafting hydrophilic acrylic acid onto PVDF and the separator, the connection between the positive active material and the separator can be mainly achieved by the tight cross-linking of the graft formed between the positive electrode binder and the separator (acrylic acid, as a hydrophilic monomer, is grafted onto the PVDF surface to increase its hydrophilicity, and under the action of a free radical initiator, acrylic acid will be converted into an excited dimer to participate in the grafting reaction, with a high affinity for the PVDF and separator main chains, which can achieve a high grafting rate). The bonding between the positive active material and the positive current collector is mainly achieved by physical adsorption formed by the van der Waals force generated between the positive electrode binder and the positive current collector. In other words, the bonding force between the positive active material and the separator is stronger than the bonding force between the positive active material and the positive current collector.

[0066] In the present disclosure, swelling may include: soaking the grafted material in water.

[0067] For reference, the soaking temperature may be 20°C-30°C, such as 20°C, 22°C, 25°C, 28°C or 30°C, or any other value within the range of 20°C-30°C.

[0068] The soaking time can be 18h-24h, such as 18h, 19h, 20h, 21h, 22h, 23h or 24h, or any other value within the range of 18h-24h.

[0069] Through the above treatment, PVDF can be swollen, increasing the distance between PVDF and the positive electrode current collector and weakening its viscosity with the positive electrode current collector; the positive electrode active material and the separator are cross-linked by the graft, and have a strong adhesive force. Therefore, under the action of external force, the positive electrode active material and the separator can be separated from the positive electrode current collector as a whole. This method can avoid the use of high-energy heat treatment (treatment temperature is about 500-600℃) and the use of large amounts of acid or alkaline solution treatment. This method is simple and effective for separating the positive electrode material and the positive electrode current collector, and takes into account low energy consumption, low cost, safety and environmental protection.

[0070] It should be noted that the above-mentioned “external force” includes any means such as pulling force or pushing force that can separate the positive electrode active material and the separator as a whole from the positive electrode current collector.

[0071] In the present disclosure, the waste batteries may be pre-treated before the grafting process, wherein the pre-treatment includes removing the electrolyte and the negative electrode from the waste batteries.

[0072] Used batteries can be disassembled first, the outer shell can be removed, and the inner core containing the positive electrode, separator and negative electrode can be obtained.

[0073] The electrolyte can be removed by heating the inner core of the used battery to volatilize the electrolyte.

[0074] For example, the heating temperature may be 140° C. to 150° C., such as 140° C., 142° C., 145° C., 148° C., or 150° C., or any other value within the range of 140° C. to 150° C. The heating time may be 1 hour to 2 hours, such as 1 hour, 1.5 hours, or 2 hours, or any other value within the range of 1 hour to 2 hours.

[0075] The above heating process can be carried out in a muffle furnace or in other heating devices.

[0076] To remove the negative electrode, the battery core, free of electrolyte, is immersed in water to dissolve the aqueous negative electrode binder (primarily composed of styrene-butadiene rubber latex (SBR)) in the negative electrode sheet. Under these conditions, the graphite naturally falls off. Subsequently, the negative electrode sheet and the detached negative electrode active material are removed, and the positive electrode sheet and the separator connected to it are collected for grafting.

[0077] For reference, the battery core after the electrolyte is removed may be immersed in water for a period of 24 hours to 48 hours, such as 24 hours, 30 hours, 36 hours, 42 hours, or 48 hours, or any other value within the range of 24 hours to 48 hours.

[0078] In some embodiments, the pre-treatment may further include: modifying the positive electrode sheet and the separator connected to the positive electrode sheet.

[0079] The treatment reagent used in the above-mentioned modification treatment can be a mixed solution of alkali and alcohol.

[0080] The base may illustratively include at least one of KOH and NaOH, and the alcohol may illustratively include ethanol.

[0081] The mass ratio of the base to the alcohol can be (1:100)-(10:100), such as 1:100, 2:100, 3:100, 4:100, 5:100, 6:100, 7:100, 8:100, 9:100 or 1:100, or any other value within the range of (1:100)-(10:100).

[0082] For reference, the temperature of the modification treatment may be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, or any other value within the range of 50°C-80°C.

[0083] The modification treatment time can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min or 90 min, etc., or any other value within the range of 30 min-90 min.

[0084] Through modification treatment, the active groups on PVDF and the diaphragm can be increased, so that carbon-carbon conjugated double bonds are formed on PVDF and the diaphragm, which is conducive to generating more free radical active points on the molecular chain, thereby increasing the active sites of the reaction and improving the grafting rate.

[0085] In the present disclosure, the positive electrode current collector and the positive electrode active material bonded with the separator may be separated by providing an external force through a negative pressure adsorption device.

[0086] Referring to Figure 1 , the negative pressure adsorption device includes a suction cup 20. The number of suction cups 20 may be one or multiple (e.g., two, three, or more). The suction cup 20 is used to adhere to the surface of the positive electrode current collector and / or separator to be separated, thereby separating the positive electrode current collector and the separator under the action of negative pressure.

[0087] The suction cup 20 is connected to a gas flow pipe (not shown). As shown in Figure 2, the surface of the suction cup 20 has a suction hole 23 (the number can be one or more), which is connected to one end of the gas flow pipe, and the other end of the gas flow pipe is connected to a pump device (not shown).

[0088] In some embodiments, taking the battery core as a wound type as an example, a partial area is wound in sequence by the first negative electrode sheet, the first separator 11, the first positive electrode sheet, the second separator 15 and the second negative electrode sheet. After removing the first negative electrode sheet and the second negative electrode sheet according to the above process, the first separator 11, the first positive electrode sheet (the first positive electrode active material layer 12, the aluminum foil layer 13, the second positive electrode active material layer 14 in sequence) and the second separator 15 remain, wherein the first positive electrode active material layer 12 is arranged opposite to the first separator 11, and the second positive electrode active material layer 14 is arranged opposite to the second separator 15. Correspondingly, one of the suction cups 20 (defined as the first suction cup 21) of the negative pressure adsorption device is adsorbed onto the first diaphragm 11, and the other suction cup 20 (defined as the second suction cup 22) is adsorbed onto the second diaphragm 15. The negative pressure adsorption device is started, and the gas flow pipe is pumped to the outside through the pump device to achieve negative pressure between the suction cup 20 and the surface of the adsorbed object. Then, by making the first suction cup 21 and the second suction cup 22 move relative to each other, the positive electrode current collector and the positive electrode active material bonded to the diaphragm can be separated.

[0089] Illustratively, the negative pressure range may be 500Pa-1000Pa, such as 500Pa, 600Pa, 700Pa, 800Pa, 900Pa or 1000Pa, or any other value within the range of 500Pa-1000Pa.

[0090] Furthermore, the separated positive electrode active material bound with the separator is crushed, and the separator is removed by sorting to obtain the positive electrode active material.

[0091] It should be noted that the positive electrode active material, negative electrode active material, positive electrode current collector, negative electrode current collector, separator, etc. obtained during the recycling method provided in the present disclosure can be recycled and reused as needed.

[0092] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0093] Example 1

[0094] This embodiment provides a full-chain integrated recycling method for processing materials in waste batteries, which includes the following steps:

[0095] S1: Manually disassemble the recycled nickel-cobalt-manganese ternary lithium-ion battery, remove the outer aluminum shell, and obtain the battery core containing the positive electrode, separator and negative electrode.

[0096] Among them, the separator of the nickel-cobalt-manganese ternary lithium-ion battery is PE, the positive electrode collector is aluminum foil, the negative electrode collector is copper foil, and the positive electrode active material is LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, the negative electrode active material is graphite, the positive electrode binder is mainly PVDF, and the negative electrode binder is mainly SBR.

[0097] S2: Place the battery core in a muffle furnace, heat it at 145°C for 1.5 hours, then cool it in the furnace to remove the electrolyte.

[0098] S3: Place the battery core with the electrolyte removed in pure water and soak it at room temperature for 36 hours to dissolve the water-based binder SBR on the negative electrode sheet. The graphite will fall off naturally, and the positive electrode sheet and separator of the battery core will be collected.

[0099] S4: Soak the positive electrode sheet and the separator in a NaOH-ethanol mixed solution with an alcohol mass fraction of 5 wt % at a soaking temperature of 75° C. for 60 min.

[0100] S5: Soak the modified positive electrode sheet and diaphragm in a n-propanol solution containing 9wt% acrylic acid, 2wt% dibenzoyl peroxide, and 3wt% diisopropyl peroxide, and place them in a constant temperature drying oven for a closed reaction for 4 hours at a reaction temperature of 70°C. After the reaction is completed, take them out and immerse them in deionized water and soak them at room temperature (25°C) for 21 hours. After the soaking is completed, take them out and dry them. The hydrophilic acrylic acid can be grafted onto the PVDF and the diaphragm at the same time.

[0101] S6: Use a negative pressure adsorption device (as shown in FIG1 ) to separate the aluminum foil and the positive electrode active material. Specifically, the first suction cup 21 in the negative pressure adsorption device is adsorbed onto the first separator 11, and the second suction cup 22 is adsorbed onto the second separator 15. The negative pressure adsorption device is activated with a negative pressure of 800 Pa, causing the first suction cup 21 and the second suction cup 22 to move relative to each other, thereby separating the aluminum foil layer 13 from the positive electrode active material bonded to the separator (the first positive electrode active material layer 12 bonded to the first separator 11 and the second positive electrode active material layer 14 bonded to the second separator 15).

[0102] S7: crushing the positive electrode active material bonded with the separator, sorting and removing the separator, and obtaining the positive electrode active material.

[0103] Example 2

[0104] This embodiment provides a full-chain integrated recycling method for processing materials in waste batteries, which includes the following steps:

[0105] S1: Same as Example 1.

[0106] S2: Place the battery core in a muffle furnace, heat it at 140°C for 1 hour, then cool it in the furnace to remove the electrolyte.

[0107] S3: Place the battery core with the electrolyte removed in pure water and soak it at room temperature for 24 hours to dissolve the water-based binder SBR on the negative electrode sheet. The graphite will fall off naturally, and the positive electrode sheet and separator of the battery core will be collected.

[0108] S4: Soak the positive electrode sheet and the separator in a KOH-ethanol mixed solution with an alcohol mass fraction of 1 wt % at a soaking temperature of 80° C. for 90 min.

[0109] S5: Soak the modified positive electrode sheet and diaphragm in a n-propanol solution containing 8wt% acrylic acid, 1wt% dibenzoyl peroxide, and 2wt% diisopropyl peroxide, and place them in a constant temperature drying oven for a closed reaction for 2 hours at a reaction temperature of 60°C. After the reaction is completed, take them out and immerse them in deionized water and soak them at room temperature (20°C) for 18 hours. After the soaking is completed, take them out and dry them. The hydrophilic acrylic acid can be grafted onto the PVDF and the diaphragm at the same time.

[0110] S6: Set the negative pressure to 1000 Pa, and the rest is the same as in Example 1.

[0111] S7: crushing the positive electrode active material bonded with the separator, sorting and removing the separator, and obtaining the positive electrode active material.

[0112] Example 3

[0113] This embodiment provides a full-chain integrated recycling method for processing materials in waste batteries, which includes the following steps:

[0114] S1: Same as Example 1.

[0115] S2: Place the battery core in a muffle furnace, heat it at 150°C for 2 hours, and then cool it in the furnace to remove the electrolyte.

[0116] S3: Place the battery core with the electrolyte removed in pure water and soak it at room temperature for 48 hours to dissolve the water-based binder SBR on the negative electrode sheet. The graphite will fall off naturally, and the positive electrode sheet and separator of the battery core will be collected.

[0117] S4: Soak the positive electrode sheet and the separator in a NaOH-ethanol mixed solution with an alcohol mass fraction of 10 wt % at a soaking temperature of 50° C. for 30 min.

[0118] S5: Soak the modified positive electrode sheet and diaphragm in a n-propanol solution containing 10wt% acrylic acid, 3wt% dibenzoyl peroxide, and 4wt% diisopropyl peroxide, and place them in a constant temperature drying oven for a closed reaction for 6 hours at a reaction temperature of 80°C. After the reaction is completed, take them out and immerse them in deionized water and soak them at room temperature (30°C) for 24 hours. After the soaking is completed, take them out and dry them. The hydrophilic acrylic acid can be grafted onto the PVDF and the diaphragm at the same time.

[0119] S6: Set the negative pressure to 500 Pa, and the rest is the same as in Example 1.

[0120] S7: crushing the positive electrode active material bonded with the separator, sorting and removing the separator, and obtaining the positive electrode active material.

[0121] Comparative Example 1

[0122] After disassembling the same used batteries as in Example 1 to obtain battery cells, the cells were disassembled to obtain positive electrode sheets. The disassembled positive electrode sheets were placed in a graphite crucible and heated in a muffle furnace at 500°C for 4 minutes in an air atmosphere. After natural cooling, the powder on the surface of the positive electrode sheets was sieved to separate the aluminum foil and positive electrode material.

[0123] Comparative Example 2

[0124] The difference between this comparative example and Example 1 is that the mass ratio of acrylic acid to dibenzoyl peroxide and dicumyl peroxide is 9:0.5:3.

[0125] Comparative Example 3

[0126] The difference between this comparative example and Example 1 is that the mass ratio of acrylic acid to dibenzoyl peroxide and dicumyl peroxide is 9:4:3.

[0127] Comparative Example 4

[0128] The difference between this comparative example and Example 1 is that the mass ratio of acrylic acid to dibenzoyl peroxide and dicumyl peroxide is 9:2:1.

[0129] Comparative Example 5

[0130] The difference between this comparative example and Example 1 is that the mass ratio of acrylic acid to dibenzoyl peroxide and dicumyl peroxide is 9:2:5.

[0131] Comparative Example 6

[0132] The difference between this comparative example and Example 1 is that the temperature of the grafting reaction is 50°C.

[0133] Comparative Example 7

[0134] The difference between this comparative example and Example 1 is that the temperature of the grafting reaction is 90°C.

[0135] Comparative Example 8

[0136] The difference between this comparative example and Example 1 is that the grafting reaction time is 1 hour.

[0137] Comparative Example 9

[0138] The difference between this comparative example and Example 1 is that the grafting reaction time is 8 hours.

[0139] Comparative Example 10

[0140] The difference between this comparative example and Example 1 is that no modification treatment was performed before grafting.

[0141] Comparative Example 11

[0142] The difference between this comparative example and Example 1 is that no swelling treatment is performed after grafting.

[0143] Test example

[0144] The recovery rates of the positive electrode active materials obtained in Examples 1-3 and Comparative Examples 1-11 and the purity of the obtained positive electrode current collectors (aluminum foils) were measured, and the results are shown in Table 1.

[0145] Table 1 Test results

[0146] As can be seen from Table 1, the methods provided in Examples 1-3 of the present disclosure can achieve a higher recovery rate of positive electrode active materials on the one hand, and can also recover a positive electrode current collector with a higher purity on the other hand. Industrial Applicability

[0147] The method provided by the present disclosure can at least effectively separate the positive electrode active material and the current collector from waste batteries. The separated materials can be further recycled. The method is simple to operate, has easily controllable conditions, low energy consumption, low cost, is environmentally friendly, and safe.

Claims

1. A method for recycling materials from waste batteries with full-chain integration, characterized in that: include: The positive electrode sheet in the waste battery and the separator connected to the positive electrode sheet are grafted to make the separator and the positive electrode binder of the positive electrode sheet cross-linked through the grafted material, and then the grafted material is swelled to reduce the bonding force between the positive electrode binder and the positive electrode collector in the positive electrode sheet, and the positive electrode collector is separated from the positive electrode active material bonded with the separator under the action of external force.

2. The recycling method according to claim 1, characterized in that: The waste battery is a waste lithium-ion battery; and / or the separator is a polymer electrolyte membrane; and / or the main component of the positive electrode binder is polyvinylidene fluoride; and / or the positive electrode current collector is aluminum foil.

3. The recycling method according to claim 1 or 2, characterized in that: The grafting treatment includes: mixing the grafting raw material with the positive electrode sheet in the waste battery and the separator connected to the positive electrode sheet and performing a grafting reaction; wherein the grafting raw material includes acrylic acid, a crosslinking agent and an initiator.

4. The recycling method according to claim 3, characterized in that: The cross-linking agent includes dibenzoyl peroxide; and / or, the initiator includes dicumyl peroxide.

5. The recycling method according to claim 4, characterized in that: The mass ratio of the acrylic acid to the dibenzoyl peroxide and the dicumyl peroxide is (8-10):(1-3):(2-4).

6. The recycling method according to claim 4 or 5, characterized in that: The grafting raw material also includes a solvent.

7. The recycling method according to claim 6, characterized in that: The solvent includes n-propanol.

8. The recycling method according to claim 6 or 7, characterized in that: For every 100 g of the solvent, 8 g to 10 g of the acrylic acid, 1 g to 3 g of the dibenzoyl peroxide and 2 g to 4 g of dicumyl peroxide are used.

9. The recycling method according to any one of claims 2 to 8, characterized in that: The grafting reaction has at least one of the following characteristics: Feature 1: The temperature of the grafting reaction is 60℃-80℃; Feature 2: The grafting reaction time is 2h-6h; Feature 3: The grafting reaction is carried out under constant temperature, closed and dry conditions.

10. The recycling method according to any one of claims 1 to 9, characterized in that: Swelling includes: The grafted material is soaked in water.

11. The recycling method according to claim 10, characterized in that: The soaking temperature is 20°C-30°C; and / or the soaking time is 18h-24h.

12. The recycling method according to any one of claims 1 to 11, characterized in that: Before the grafting treatment, the method also includes: pre-treating the waste batteries; Pre-treatment includes: removing the electrolyte and negative electrode from the used batteries.

13. The recycling method according to claim 12, characterized in that: Removing the electrolyte includes: heating the inner core of the waste battery to volatilize and remove the electrolyte.

14. The recycling method according to claim 13, characterized in that: The heating temperature is 140° C.-150° C.; and / or the heating time is 1 h-2 h.

15. The recycling method according to claim 12, characterized in that: Removing the negative electrode sheet includes: soaking the battery core with the electrolyte removed in water to dissolve the negative electrode binder in the negative electrode sheet in water, removing the negative electrode sheet and the negative electrode active material falling off the negative electrode collector of the negative electrode sheet, and collecting the positive electrode sheet and the separator connected to the positive electrode sheet.

16. The recycling method according to claim 15, characterized in that: The soaking time is 24h-48h.

17. The recycling method according to claim 15 or 16, characterized in that: The negative electrode current collector is copper foil.

18. The recycling method according to any one of claims 15 to 17, characterized in that: The pre-treatment also includes: modifying the positive electrode sheet and the separator connected to the positive electrode sheet.

19. The recycling method according to claim 18, characterized in that: The modification process has at least one of the following characteristics: Feature 1: The treatment reagent used in the modification treatment is a mixed solution of alkali and alcohol; Feature 2: The temperature of the modification treatment is 50℃-80℃; Feature 3: The modification treatment time is 30min-90min.

20. The recycling method according to claim 19, characterized in that: The base includes at least one of KOH and NaOH; and / or the alcohol includes ethanol; and / or the mass ratio of the base to the alcohol is (1:100)-(10:100).

21. The recycling method according to any one of claims 1 to 20, characterized in that: The positive electrode current collector and the positive electrode active material bonded with the separator are separated by providing external force through a negative pressure adsorption device.

22. The recycling method according to claim 21, characterized in that: The negative pressure adsorption device comprises a suction cup, which is used to be adsorbed on the surface of the positive electrode current collector and / or the separator to be separated so as to separate the positive electrode current collector and the separator under the action of negative pressure.

23. The recycling method according to claim 22, characterized in that: The suction cup is connected with a gas circulation pipeline.

24. The recycling method according to claim 23, characterized in that: The plate surface of the suction cup is provided with a suction hole, and the suction hole is communicated with the gas flow pipeline.

25. The recycling method according to any one of claims 23-24, characterized in that: The negative pressure range is 500Pa-1000Pa.

26. The recycling method according to any one of claims 21 to 25, characterized in that: The separated positive electrode active material bonded with the separator is crushed, and the separator is removed by sorting to obtain the positive electrode active material.

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