Method for recycling waste batteries

Abstract

The invention provides a method for recycling a waste battery. The method comprises the following steps: punching the waste battery, and extracting electrolyte; after extracting the electrolyte, splitting to obtain a battery shell, a positive plate, a negative plate and a diaphragm; immersing the negative plate into an aqueous solution containing a first stripping agent, stripping the negative electrode powder, and recovering to obtain the negative electrode powder and a negative electrode foil; and immersing the positive plate into an aqueous solution containing a second stripping agent, stripping the positive powder, and recovering to obtain the positive powder and the positive foil. According to the method, the electrolyte is pumped out after the waste battery is punched instead of a drying mode, so that the energy consumption and the cost are reduced, the purity of the positive and negative electrode powder is improved, meanwhile, the positive and negative electrode pieces are separately subjected to dipping treatment, the positive electrode powder, the negative electrode powder and the diaphragm obtained through separation are high in purity, the positive electrode powder can be directly used, and the service life of the battery is prolonged. And synthesis after wet lithium extraction is not needed, and the value of the negative electrode powder is high.

Description

Technical Field

[0001] The invention belongs to the technical field of battery recycling and relates to a method for recycling waste batteries. Background Art

[0002] With the vigorous development of the new energy field, the recycling and utilization of waste lithium batteries has become a focus of attention in existing technologies. Lithium batteries mainly include copper foil, aluminum foil, diaphragm, electrolyte, binder and black powder. The current method of recycling lithium batteries is mainly to dry the batteries, separate the positive and negative electrodes, and crush them separately to obtain positive and negative electrode powder, copper powder and aluminum powder.

[0003] For example, CN119315156A discloses a method for comprehensive recycling of waste lithium-ion batteries, comprising the following steps: S1, discharging, shelling, and sawing waste lithium iron phosphate batteries and waste ternary lithium-ion batteries to obtain waste battery powder; S2, drying, breaking up, and air-selecting the waste battery powder to obtain separators and membrane-removed waste battery powder; S3, subjecting the membrane-removed waste battery powder to XRT photoelectric separation to obtain positive electrode sheet powder and negative electrode sheet powder; S4, grinding and first screening the positive electrode sheet powder to obtain positive electrode material powder and aluminum products; S5, mixing the positive electrode material powder and the separator and performing oxygen-free roasting to obtain roasting slag; S6, magnetically separating the roasting slag to obtain magnetic products and non-magnetic products, wherein the magnetic separation products include magnetic nickel, cobalt, manganese, and iron products.

[0004] In the existing technology for recycling lithium-ion batteries, the drying process consumes a lot of energy and has a certain risk of explosion. It also causes a certain amount of oxidation to the copper foil and aluminum foil. After the positive and negative electrodes are crushed and powdered, there is a certain amount of aluminum powder in the positive electrode powder and a certain amount of copper powder in the negative electrode powder. The purity of the positive and negative electrode powders is poor. In addition, the positive electrode powder usually needs to be recovered by wet method before the lithium is synthesized into the positive electrode material, which increases the cost. The negative electrode graphite is usually of little value due to the high impurity content.

[0005] Based on the above research, it is necessary to provide a method for recycling waste batteries. The positive electrode powder, negative electrode powder and separator recovered by the method are of high purity. The positive electrode powder can be used directly without wet lithium extraction and then synthesis. The negative electrode powder has high value, and the recycling cost is low, and the recycling process is highly safe. Summary of the Invention

[0006] The object of the present invention is to provide a method for recycling waste batteries. The method extracts the electrolyte after punching the waste batteries instead of drying them, which not only reduces energy consumption and cost but also improves the purity of positive and negative electrode powders. At the same time, the positive and negative electrode sheets are separately impregnated, and the separated positive electrode powder, negative electrode powder and separator are of high purity. The positive electrode powder can be used directly without wet lithium extraction and then synthesis, and the negative electrode powder is of high value.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for recycling waste batteries, the method comprising the following steps:

[0009] (1) Punch holes in the used batteries and extract the electrolyte;

[0010] (2) After the electrolyte is extracted, the battery is disassembled to obtain a battery shell, a positive electrode sheet, a negative electrode sheet, and a separator;

[0011] (3) immersing the negative electrode sheet described in step (2) in an aqueous solution containing a first stripping agent to strip the negative electrode powder, and recovering the negative electrode powder and the negative electrode foil;

[0012] The positive electrode sheet described in step (2) is immersed in an aqueous solution containing a second stripping agent to strip the positive electrode powder, and the positive electrode powder and positive electrode foil are recovered.

[0013] The present invention extracts the electrolyte after punching the waste battery instead of removing the electrolyte by drying, which not only reduces energy consumption but also avoids the influence of drying on the purity of positive and negative electrode powders. The method of extracting the electrolyte by the present invention can improve the purity of positive and negative electrode powders; after extracting the electrolyte, the battery is disassembled, and then the positive electrode sheet and the negative electrode sheet are sorted respectively to separate the positive electrode powder from the positive electrode foil, and the negative electrode powder from the negative electrode foil. The sorting method described in the present invention is to immerse the electrode sheet in an aqueous solution containing a stripping agent to achieve the separation of the powder and the foil, and avoids the problem of foil material entering the powder and affecting the purity to the greatest extent, further improving the purity of the obtained positive and negative electrode powders. In addition, the recovered positive electrode powder does not need to be synthesized after wet recovery of lithium, the negative electrode powder has low impurity content and high value, the diaphragm is clean and complete, and can be used for sale, and the foil has high purity and high value.

[0014] The waste battery described in the present invention is a lithium iron phosphate waste battery, the positive electrode powder includes lithium iron phosphate powder, and the negative electrode powder includes graphite powder.

[0015] Preferably, the temperature of the aqueous solution containing the first stripping agent in step (3) is 60°C-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, when the negative electrode powder is stripped in step (3), ultrasound and / or stirring are not performed.

[0017] Preferably, the time of immersing in the aqueous solution containing the first stripping agent in step (3) is 25 min-35 min, for example, 25 min, 30 min or 35 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the EC (electrical conductivity) of water in the aqueous solution containing the first stripping agent in step (3) is 0.1 μs / cm-1.0 μs / cm, for example, 0.1 μs / cm, 0.3 μs / cm, 0.5 μs / cm, 0.7 μs / cm or 1.0 μs / cm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] The aqueous solution containing the first stripping agent of the present invention is obtained by mixing water and the first stripping agent, wherein the EC of the water used for the mixing is 0.1 μs / cm-1.0 μs / cm as mentioned above.

[0020] Preferably, in step (3), the first stripping agent comprises any one of benzotriazole, phytic acid or 8-hydroxyquinoline, or a combination of at least two thereof.

[0021] The present invention uses a first stripping agent such as benzotriazole to assist in stripping the negative electrode powder. The principle that the first stripping agent such as benzotriazole can promote stripping and improve the purity of the negative electrode powder is that it can form a stable complex with copper ions, preventing the metal foil from dissolving and improving the purity of the negative electrode powder.

[0022] Preferably, in the aqueous solution containing the first stripping agent in step (3), the concentration of the first stripping agent is 2 mg / L-4 mg / L, for example, it can be 2 mg / L, 3 mg / L or 4 mg / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the temperature of the aqueous solution containing the second stripping agent in step (3) is 60°C-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] When the positive electrode powder and the negative electrode powder are stripped in the present invention, the temperature of the aqueous solution will affect the purity of the product. If the temperature is too high, the aluminum content of the lithium iron phosphate positive electrode material will increase significantly, and the copper content of the graphite powder will increase significantly. If the temperature is too low, the purity of the copper foil and the aluminum foil will decrease significantly.

[0025] Preferably, when the positive electrode powder is stripped in step (3), ultrasound and / or stirring are not performed.

[0026] When stripping the positive and negative electrode powders, the present invention only needs to immerse them in an aqueous solution containing a stripping agent without ultrasonication and / or stirring, which can further prevent the foil material from entering the powder and affecting the purity of the powder.

[0027] Preferably, the time of immersing in the aqueous solution containing the second stripping agent in step (3) is 25 min-35 min, for example, 25 min, 30 min or 35 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the EC of water in the aqueous solution containing the second stripping agent in step (3) is 0.1 μs / cm-1.0 μs / cm, for example, 0.1 μs / cm, 0.3 μs / cm, 0.5 μs / cm, 0.7 μs / cm or 1.0 μs / cm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] The aqueous solution containing the second stripping agent of the present invention is obtained by mixing water and the second stripping agent, wherein the EC of the water used for the mixing is 0.1 μs / cm-1.0 μs / cm as mentioned above.

[0030] Preferably, in step (3), the second stripping agent comprises any one of imidazoline, polyaspartic acid or flavonoids (such as doxyflavonoids) or a combination of at least two thereof.

[0031] The present invention uses a second stripping agent such as imidazoline to assist in the stripping of the positive electrode powder. The principle that the second stripping agent such as imidazoline can promote stripping and improve the purity of the positive electrode powder is that it can chelate with aluminum ions to form a dense multi-molecular layer protective film, prevent the metal foil from dissolving, and improve the purity of the positive electrode powder.

[0032] Preferably, in the aqueous solution containing the second stripping agent in step (3), the content of the second stripping agent is 0.1wt%-0.3wt%, for example, it can be 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt% or 0.3wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the method of immersing the negative electrode sheet in step (2) into an aqueous solution containing a first stripping agent includes: using three-D vision plus a robotic arm to pull the negative electrode sheet through the aqueous solution containing the first stripping agent (the electrode sheet stays for 25 minutes to 35 minutes), and after stripping the negative electrode powder, the three-D vision plus a robotic arm winds and collects the negative electrode foil.

[0034] Preferably, the method of immersing the positive electrode sheet in step (2) into an aqueous solution containing a second stripping agent includes: using three-D vision plus a robotic arm to pull the positive electrode sheet through the aqueous solution containing the second stripping agent (the electrode sheet stays for 25 minutes to 35 minutes), and after stripping the positive electrode powder, the three-D vision plus the robotic arm winds and collects the positive electrode foil.

[0035] In the method described in the present invention, three-D vision and robotic arms are used in multiple places, and the degree of automation is high.

[0036] Preferably, after the negative electrode powder is stripped in step (3), centrifugation and a first calcination are performed to recover the negative electrode powder.

[0037] Preferably, the temperature of the first calcination is 350°C-450°C, for example, 350°C, 400°C or 450°C, and the time is 40min-60min, for example, 40min, 50min or 60min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, after the positive electrode powder is stripped in step (3), centrifugation and a second calcination are performed to recover the positive electrode powder;

[0039] Preferably, the temperature of the second calcination is 550°C-650°C, for example, 550°C, 600°C or 650°C, and the time is 60min-80min, for example, 60min, 70min or 80min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the method for splitting in step (2) includes the following steps: cutting off the cover of the battery shell by laser cutting, then taking out the bare battery cell by three-D vision plus a robotic arm and winding and separating the positive electrode sheet, the negative electrode sheet and the diaphragm.

[0041] Preferably, the electrolyte in step (1) is extracted by vacuum suction.

[0042] Preferably, the vacuum degree of the vacuum suction is below -0.1Pa, for example, it can be -0.1Pa, -0.15Pa or -0.2Pa, and the time is 30-60min, for example, it can be 30min, 40min, 50min or 60min, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the step of extracting the electrolyte after punching the waste battery in step (1) includes: using 3D vision and a robotic arm to break the explosion relief valve of the waste battery, and at the same time adsorbing a suction cup on the explosion relief valve to suck the electrolyte.

[0044] Preferably, when extracting the electrolyte in step (1), the used battery is inverted with the explosion relief valve facing downward.

[0045] Specifically, the present invention uses three-D vision and a robotic arm to place the waste lithium battery on a fixture and fix it, then breaks the explosion relief valve, and at the same time, a suction cup is adsorbed on the explosion relief valve. The suction cup is connected to a stainless steel screw vacuum pump to suck out the electrolyte. The waste lithium battery is placed upside down on the fixture with the explosion relief valve facing downward.

[0046] The system used in the method of the present invention includes: an intelligent drilling and liquid extraction system for breaking the explosion relief valve of waste batteries and extracting electrolyte;

[0047] Intelligent cutting and sorting system, used to cut the aluminum shell and separate the aluminum shell, positive electrode sheet, negative electrode sheet and diaphragm;

[0048] Negative electrode sheet stripping and sorting system, used to separate negative electrode powder from negative electrode foil;

[0049] Positive electrode sheet stripping and sorting system is used to separate positive electrode powder from positive electrode foil.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention extracts the electrolyte after punching the waste battery instead of removing the electrolyte by drying, which not only reduces energy consumption but also avoids the influence of drying on the purity of positive and negative electrode powders. The method of extracting the electrolyte by the present invention can improve the purity of positive and negative electrode powders; after extracting the electrolyte, the battery is disassembled, and then the positive electrode sheet and the negative electrode sheet are sorted respectively to separate the positive electrode powder from the positive electrode foil, and the negative electrode powder from the negative electrode foil. The sorting method described in the present invention is to immerse the electrode sheet in an aqueous solution containing a stripping agent to achieve the separation of the powder and the foil, and avoids the problem of foil material entering the powder and affecting the purity to the greatest extent, further improving the purity of the obtained positive and negative electrode powders. In addition, the recovered positive electrode powder does not need to be synthesized after wet recovery of lithium, the negative electrode powder has low impurity content and high value, the diaphragm is clean and complete, and can be used for sale, and the foil has high purity and high value.

[0052] Specifically, the recovered positive electrode powder meets the requirements of GB / T 30835-2014, the recovered negative electrode powder meets the requirements of GB / T 24533-2019, the purity of the recovered negative electrode foil is greater than 99.9%, and the purity of the positive electrode foil is greater than 99.9%. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The present invention is a flowchart of the method for recycling used batteries. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Example 1

[0056] This embodiment provides a method for recycling waste batteries. The flowchart of the method is as follows: Figure 1 As shown, the method specifically includes the following steps:

[0057] (1) The waste lithium iron phosphate battery is grasped by the three-D vision and robotic arm to the fixture, and the waste lithium iron phosphate battery is turned upside down. After the three-D vision and robotic arm break the safety valve, the suction cup is aligned with the safety valve opening, and the screw vacuum pump is turned on to suck the electrolyte. The relative vacuum degree of the suction is -0.1 Pa, and the suction time of the suction cup is 40 minutes;

[0058] (2) Use a laser cutter to cut the battery shell on the fixture, and use 3D vision and a robotic arm to remove the shell, while winding the positive electrode sheet, negative electrode sheet and separator;

[0059] (3) The positive electrode sheet is slowly pulled through a water tank by a three-D vision and robotic arm. The water tank is filled with pure water with EC = 0.1 μs / cm. Imidazoline is added to the pure water to form an aqueous solution containing 0.2 wt% imidazoline. The positive electrode sheet stays for 30 minutes. The water temperature is 70 ° C. The lithium iron phosphate powder falls into the water tank. The three-D vision and robotic arm wind up the aluminum foil to collect it. The lithium iron phosphate powder is centrifuged in a centrifuge and then enters a rotary kiln for roasting. The roasting temperature is 580 ° C and the roasting time is 70 minutes to obtain a lithium iron phosphate positive electrode material.

[0060] The negative electrode sheet is slowly pulled through a water tank by 3D vision and a robotic arm. The water tank is filled with pure water with an EC of 0.1 μs / cm. Benzotriazole is added to the pure water to form an aqueous solution containing 3 mg / L benzotriazole. The negative electrode sheet stays in the water tank for 30 minutes at a water temperature of 70°C. Graphite powder falls into the water tank. 3D vision and a robotic arm wind and collect the copper foil. After the graphite powder is centrifuged in a centrifuge, it enters a rotary kiln for roasting at a temperature of 400°C for 50 minutes to obtain battery-grade graphite powder.

[0061] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this example are shown in Table 1:

[0062] Table 1

[0063]

[0064] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 2:

[0065] Table 2

[0066] unit result Li ％ 4.8 P ％ 19.31 Fe ％ 32.1 C ％ 2.71 Mo ％ 0.22 Ni ％ 0.003 Pb ％ 0.001 Tap density <![CDATA[g / cm 3 ]]> 1.23 Specific surface area <![CDATA[m 2 / g]]> 15.21 Particle size D50 μm 3.18 Al ％ 0

[0067] The purity of the copper foil and aluminum foil recovered in this embodiment is shown in Table 3:

[0068] Table 3

[0069] unit result Purity of copper foil ％ 99.99 Purity of aluminum foil ％ 99.99

[0070] Example 2

[0071] This embodiment provides a method for recycling used batteries, the method comprising the following steps:

[0072] (1) The waste lithium iron phosphate battery is grasped by the three-D vision and robotic arm to the fixture, and the waste lithium iron phosphate battery is turned upside down. After the three-D vision and robotic arm break the safety valve, the suction cup is aligned with the safety valve opening, and the screw vacuum pump is turned on to suck the electrolyte. The relative vacuum degree of the suction is -0.15 Pa, and the suction time of the suction cup is 30 minutes;

[0073] (2) Use a laser cutter to cut the battery shell on the fixture, and use 3D vision and a robotic arm to remove the shell, while winding the positive electrode sheet, negative electrode sheet and separator;

[0074] (3) The positive electrode sheet is slowly pulled through a water tank by a 3D vision and robotic arm. The water tank is filled with pure water with EC = 0.5 μs / cm. Polyaspartic acid is added to the pure water to form an aqueous solution containing 0.1 wt% polyaspartic acid. The positive electrode sheet stays for 35 minutes. The water temperature is 60 ° C. The lithium iron phosphate powder falls into the water tank. The 3D vision and robotic arm wind up the aluminum foil to collect it. The lithium iron phosphate powder is centrifuged in a centrifuge and then enters a rotary kiln for roasting. The roasting temperature is 650 ° C and the roasting time is 60 minutes to obtain a lithium iron phosphate positive electrode material.

[0075] The negative electrode sheet is slowly pulled through a water tank by 3D vision and a robotic arm. The water tank is filled with pure water with EC = 0.5μs / cm. Phytic acid is added to the pure water to form an aqueous solution containing 4mg / L phytic acid. The negative electrode sheet stays in the water tank for 35 minutes. The water temperature is 60℃. The graphite powder falls into the water tank. The 3D vision and robotic arm wind and collect the copper foil. After the graphite powder is centrifuged in a centrifuge, it enters a rotary kiln for roasting at a temperature of 450℃ and a roasting time of 40 minutes to obtain battery-grade graphite powder.

[0076] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this example are shown in Table 4:

[0077] Table 4

[0078]

[0079]

[0080] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 5:

[0081] Table 5

[0082] unit result Li ％ 4.75 P ％ 19.33 Fe ％ 32.5 C ％ 2.73 Mo ％ 0.23 Ni ％ 0.004 Pb ％ 0.002 Tap density <![CDATA[g / cm 3 ]]> 1.22 Specific surface area <![CDATA[m 2 / g]]> 15.01 Particle size D50 μm 3.15 Al ％ 0

[0083] The purity of the copper foil and aluminum foil recovered in this embodiment is shown in Table 6:

[0084] Table 6

[0085]

[0086]

[0087] Example 3

[0088] This embodiment provides a method for recycling used batteries, the method comprising the following steps:

[0089] (1) The waste lithium iron phosphate battery is grasped by the three-D vision and robotic arm to the fixture, and the waste lithium iron phosphate battery is turned upside down. After the three-D vision and robotic arm break the safety valve, the suction cup is aligned with the safety valve opening, and the screw vacuum pump is turned on to suck the electrolyte. The relative vacuum degree of the suction is -0.1 Pa, and the suction time of the suction cup is 60 minutes;

[0090] (2) Use a laser cutter to cut the battery shell on the fixture, and use 3D vision and a robotic arm to remove the shell, while winding the positive electrode sheet, negative electrode sheet and separator;

[0091] (3) The positive electrode sheet is slowly pulled through a water tank by a three-D vision and robotic arm. The water tank is filled with pure water with EC = 1 μs / cm. Imidazoline is added to the pure water to form an aqueous solution containing 0.3 wt% imidazoline. The positive electrode sheet stays for 25 minutes. The water temperature is 80 ° C. The lithium iron phosphate powder falls into the water tank. The three-D vision and robotic arm collect the aluminum foil by winding it. After centrifugation in a centrifuge, it enters a rotary kiln for roasting. The roasting temperature is 550 ° C and the roasting time is 80 minutes to obtain a lithium iron phosphate positive electrode material.

[0092] The negative electrode sheet is slowly pulled through a water tank by 3D vision and a robotic arm. The water tank is filled with pure water with EC = 1μs / cm. Benzotriazole is added to the pure water to form an aqueous solution containing 2mg / L benzotriazole. The negative electrode sheet stays in the water tank for 25 minutes. The water temperature is 80℃. The graphite powder falls into the water tank. The 3D vision and robotic arm wind up the copper foil to collect it. After the graphite powder is centrifuged, it enters a rotary kiln for roasting at a temperature of 350℃ and a roasting time of 60 minutes to obtain battery-grade graphite powder. The 3D vision and robotic arm wind up the copper foil to collect it.

[0093] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this example are shown in Table 7:

[0094] Table 7

[0095]

[0096] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 8:

[0097] Table 8

[0098]

[0099]

[0100] The purity of the copper foil and aluminum foil recovered in this embodiment is shown in Table 9:

[0101] Table 9

[0102] unit result Purity of copper foil ％ 99.99 Purity of aluminum foil ％ 99.99

[0103] Example 4

[0104] This embodiment provides a method for recycling waste batteries, which is the same as that of embodiment 1 except that the temperature of the water tank where the positive electrode sheet stays is 50°C and the temperature of the water tank where the negative electrode sheet stays is 50°C in step (3).

[0105] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this example are shown in Table 10:

[0106] Table 10

[0107]

[0108]

[0109] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 11:

[0110] Table 11

[0111] unit result Li ％ 4.3 P ％ 19.52 Fe ％ 33.1 C ％ 2.68 Mo ％ 0.24 Ni ％ 0.005 Pb ％ 0.001 Tap density <![CDATA[g / cm 3 ]]> 1.25 Specific surface area <![CDATA[m 2 / g]]> 15.77 Particle size D50 μm 3.39 Al ％ 0

[0112] The purity of the copper foil and aluminum foil recovered in this embodiment is shown in Table 12:

[0113] Table 12

[0114] unit result Purity of copper foil ％ 85.21 Purity of aluminum foil ％ 79.13

[0115] Example 5

[0116] This embodiment provides a method for recycling waste batteries, which is the same as that of embodiment 1 except that the temperature of the water tank where the positive electrode sheet resides in step (3) is 90°C and the temperature of the water tank where the negative electrode sheet resides is 90°C.

[0117] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this example are shown in Table 13:

[0118] Table 13

[0119]

[0120] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 14:

[0121] Table 14

[0122]

[0123]

[0124] The purity of the copper foil and aluminum foil recovered in this embodiment is shown in Table 15:

[0125] Table 15

[0126] unit result Purity of copper foil ％ 99.96 Purity of aluminum foil ％ 99.96

[0127] Example 6

[0128] This embodiment provides a method for recycling used batteries. The method is the same as that of Example 1, except that in step (3), the positive electrode sheet is also subjected to ultrasound (the ultrasound power is 300W) while staying in the water tank, and the negative electrode sheet is also subjected to ultrasound (the ultrasound power is 300W) while staying in the water tank.

[0129] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this example are shown in Table 16:

[0130] Table 16

[0131]

[0132]

[0133] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 17:

[0134] Table 17

[0135] unit result Li ％ 4.5 P ％ 18.31 Fe ％ 31.1 C ％ 2.61 Mo ％ 0.32 Ni ％ 0.002 Pb ％ 0.004 Tap density <![CDATA[g / cm 3 ]]> 1.13 Specific surface area <![CDATA[m 2 / g]]> 14.21 Particle size D50 μm 3.58 Al ％ 0.08

[0136] The purity of the copper foil and aluminum foil recovered in this example are shown in Table 18:

[0137] Table 18

[0138] unit result Purity of copper foil ％ 99.99 Purity of aluminum foil ％ 99.99

[0139] Comparative Example 1

[0140] This comparative example provides a method for recycling waste batteries. The method is the same as Example 1 except that in step (1), the electrolyte is not pumped out, but the waste lithium iron phosphate battery is dried at 100° C. for 5 hours after the safety valve is broken.

[0141] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this comparative example are shown in Table 19:

[0142] Table 19

[0143]

[0144] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 20:

[0145] Table 20

[0146] unit result Li ％ 4.7 P ％ 19.21 Fe ％ 32.5 C ％ 2.78 Mo ％ 0.25 Ni ％ 0.005 Pb ％ 0.002 Tap density <![CDATA[g / cm 3 ]]> 1.25 Specific surface area <![CDATA[m 2 / g]]> 15.23 Particle size D50 μm 3.19 Al ％ 0.22

[0147] The purity of the copper foil and aluminum foil recovered in this example are shown in Table 21:

[0148] Table 21

[0149] unit result Purity of copper foil ％ 99.81 Purity of aluminum foil ％ 99.20

[0150] Comparative Example 2

[0151] This comparative example provides a method for recycling waste batteries, which is the same as Example 1 except that imidazoline and benzotriazole are not added in step (3).

[0152] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this comparative example are shown in Table 22:

[0153] Table 22

[0154]

[0155] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 23:

[0156] Table 23

[0157]

[0158]

[0159] The purity of the copper foil and aluminum foil recovered in this example are shown in Table 24:

[0160] Table 24

[0161] unit result Purity of copper foil ％ 99.72 Purity of aluminum foil ％ 99.86

[0162] Comparative Example 3

[0163] This comparative example provides a method for recycling waste batteries, which is the same as Example 1 except that in step (3), the solution in the water tank where the positive electrode sheet resides is N-methylpyrrolidone and the solution in the water tank where the negative electrode sheet resides is N-methylpyrrolidone.

[0164] The particle size D10, particle size D50, particle size D90, true density, tap density, specific surface area, ash content and copper content of the graphite powder recovered in this comparative example are shown in Table 25:

[0165] Table 25

[0166]

[0167]

[0168] The element content, tap density, specific surface area, particle size D50 and Al content of the lithium iron phosphate positive electrode material recovered in this example are shown in Table 26:

[0169] Table 26

[0170] unit result Li ％ 4.9 P ％ 19.41 Fe ％ 31.1 C ％ 2.81 Mo ％ 0.25 Ni ％ 0.004 Pb ％ 0.002 Tap density <![CDATA[g / cm 3 ]]> 1.25 Specific surface area <![CDATA[m 2 / g]]> 15.23 Particle size D50 μm 3.17 Al ％ 0.3

[0171] The purity of the copper foil and aluminum foil recovered in this example are shown in Table 27:

[0172] Table 27

[0173]

[0174]

[0175] In the above table, the particle size was obtained by testing with a laser particle size analyzer, the true density was obtained by testing with a gas displacement method, and the tap density was obtained by testing with a mechanical vibration method; the specific surface area was obtained by testing with a BET multi-point method; and the ash content, element content, and foil purity were obtained by testing with a dry ashing method and an ICP method, respectively.

[0176] From the above table we can see that:

[0177] It can be seen from Example 1 and Comparative Example 1 that the present invention can improve the purity of the obtained positive electrode powder, negative electrode powder and foil by sucking the electrolyte compared with the method of drying the electrolyte; it can be seen from Example 1 and Comparative Example 2 that the present invention adds a stripping agent to the aqueous solution for stripping the negative electrode powder and the positive electrode powder, which not only promotes the stripping of the powder, but also prevents the dissolution of the metal foil, thereby improving the purity of the obtained positive electrode powder, negative electrode powder and foil; it can be seen from Example 1 and Comparative Example 3 that the present invention uses an aqueous solution containing a stripping agent to strip the powder, and the obtained powder has high value and high purity, and the foil has high purity; it can be seen from Example 1 and Examples 4-5 that the temperature during the stripping of the positive and negative electrode powders of the present invention will affect the purity of the powders, preferably within a suitable temperature range; it can be seen from Example 1 and Example 6 that the present invention does not perform auxiliary stripping such as ultrasound or stirring during stripping, and can still ensure effective stripping and the purity of the positive and negative electrode powders.

[0178] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recycling waste batteries, characterized in that: The method comprises the following steps: (1) Punch holes in the used batteries and extract the electrolyte; (2) After extracting the electrolyte, the battery is disassembled to obtain the battery shell, positive electrode sheet, negative electrode sheet and separator; (3) immersing the negative electrode sheet described in step (2) in an aqueous solution containing a first stripping agent to strip the negative electrode powder, and recovering the negative electrode powder and the negative electrode foil; The positive electrode sheet described in step (2) is immersed in an aqueous solution containing a second stripping agent to strip the positive electrode powder, and the positive electrode powder and positive electrode foil are recovered.

2. The method according to claim 1, characterized in that The temperature of the aqueous solution containing the first stripping agent in step (3) is 60° C.-80° C.; Preferably, when the negative electrode powder is stripped in step (3), ultrasound and / or stirring are not performed; Preferably, the time of immersing in the aqueous solution containing the first stripping agent in step (3) is 25 min-35 min; Preferably, the EC of water in the aqueous solution containing the first stripping agent in step (3) is 0.1 μs / cm-1.0 μs / cm.

3. The method according to claim 1 or 2, characterized in that Step (3) the first stripping agent comprises any one of benzotriazole, phytic acid or 8-hydroxyquinoline or a combination of at least two thereof; Preferably, in the aqueous solution containing the first stripping agent in step (3), the concentration of the first stripping agent is 2 mg / L-4 mg / L.

4. The method according to any one of claims 1 to 3, characterized in that The temperature of the aqueous solution containing the second stripping agent in step (3) is 60° C.-80° C.; Preferably, when the positive electrode powder is peeled off in step (3), ultrasound and / or stirring are not performed; Preferably, the time of immersing in the aqueous solution containing the second stripping agent in step (3) is 25 min-35 min; Preferably, the EC of water in the aqueous solution containing the second stripping agent in step (3) is 0.1 μs / cm-1.0 μs / cm.

5. The method according to any one of claims 1 to 4, characterized in that Step (3) the second stripping agent comprises any one of imidazoline, polyaspartic acid or flavonoids or a combination of at least two thereof; Preferably, in the aqueous solution containing the second stripping agent in step (3), the content of the second stripping agent is 0.1 wt%-0.3 wt%.

6. The method according to any one of claims 1 to 5, characterized in that The method of immersing the negative electrode sheet in the aqueous solution containing the first stripping agent in step (2) comprises: using 3D vision plus a robotic arm to pull the negative electrode sheet through the aqueous solution containing the first stripping agent, and after stripping the negative electrode powder, the 3D vision plus a robotic arm winds and collects the negative electrode foil; Preferably, the method of immersing the positive electrode sheet in step (2) into an aqueous solution containing a second stripping agent includes: using three-D vision plus a robotic arm to pull the positive electrode sheet through the aqueous solution containing the second stripping agent, and after stripping the positive electrode powder, the three-D vision plus a robotic arm winds and collects the positive electrode foil.

7. The method according to any one of claims 1 to 6, characterized in that After the negative electrode powder is stripped in step (3), centrifugation and a first calcination are performed to recover the negative electrode powder; Preferably, the temperature of the first calcination is 350°C-450°C, and the time is 40min-60min; Preferably, after the positive electrode powder is stripped in step (3), centrifugation and a second calcination are performed to recover the positive electrode powder; Preferably, the second calcination temperature is 550° C.-650° C., and the time is 60 min-80 min.

8. The method according to any one of claims 1 to 7, characterized in that The method for splitting described in step (2) includes the following steps: cutting off the cover of the battery shell by laser cutting, then taking out the bare battery cell by three-D vision plus a robotic arm and winding and separating the positive electrode sheet, the negative electrode sheet and the diaphragm.

9. The method according to any one of claims 1 to 8, characterized in that Extracting the electrolyte in step (1) by vacuum suction; Preferably, the vacuum degree of the vacuum suction is below -0.1 Pa, and the time is 30-60 minutes.

10. The method according to any one of claims 1 to 9, characterized in that: The step of extracting the electrolyte after punching the waste battery in step (1) includes: using 3D vision and a robotic arm to break the explosion relief valve of the waste battery, and at the same time adsorbing a suction cup on the explosion relief valve to suck the electrolyte; Preferably, when extracting the electrolyte in step (1), the used battery is inverted with the explosion relief valve facing downward.

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