Retired lithium battery electrolyte recovery process
By performing steps such as stirring lithium hydroxide solution, treating with hydrofluoric acid, and calcining at high temperature on retired lithium batteries, the problem of low electrolyte recovery efficiency in existing technologies has been solved, achieving efficient and environmentally friendly electrolyte recovery and producing lithium hexafluorophosphate in compliance with standards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG SHANGAO NEW ENERGY CO LTD
- Filing Date
- 2024-06-04
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies for lithium battery electrolyte recovery suffer from low efficiency, high energy consumption, and complex processes, which are not conducive to industrial production. Furthermore, there is limited research on electrolyte recovery.
A process for recycling electrolyte from retired lithium batteries is employed, which includes stirring and reacting the retired lithium batteries in a lithium hydroxide solution, adding a catalyst, then treating them in a hydrofluoric acid solution and calcining them at high temperature, and finally introducing PF5 gas under an inert atmosphere. After the reaction, the mixture is frozen and crystallized to obtain lithium hexafluorophosphate.
This improved the electrolyte recovery efficiency, and the obtained lithium hexafluorophosphate met the standard requirements, achieving resource conservation and environmentally friendly recycling.
Smart Images
Figure BDA0004874956610000071 
Figure BDA0004874956610000081
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery recycling technology, and in particular to a process for recycling electrolyte from retired lithium batteries. Background Technology
[0002] Lithium battery recycling is a crucial part of the entire battery lifecycle. Taking power batteries as an example, the entire lifecycle value chain refers to "power battery recycling - nickel-cobalt-lithium battery raw material remanufacturing - battery material remanufacturing - power battery remanufacturing".
[0003] The booming development of the new energy vehicle market has led to a sharp increase in demand for power battery materials. Waste batteries contain various recyclable metal resources. Taking ternary lithium batteries as an example, their cathodes contain a large amount of precious metals, with lithium accounting for 2%-5%, cobalt for 5%-20%, and nickel for 5%-12%. Driven by market demand, the supply and demand imbalance of upstream raw materials such as nickel, cobalt, and lithium has led to a surge in raw material prices, putting enormous pressure on downstream cathode material companies and power battery companies in terms of raw material procurement. The supply of nickel, cobalt, and lithium is relatively tight. Therefore, the recycling of waste power lithium batteries will enable the reuse of these metal materials, allowing manufacturers to mitigate some of the negative impacts of battery material price fluctuations from the supply side and generate higher recycling revenue.
[0004] A waste lithium-ion battery electrolyte recycling device (patent publication number: CN207753130U) includes three electrolyte dissolvers arranged side by side, and a solid-liquid separator, a filter, a filtrate collection device, and a vacuum distillation device connected sequentially to each electrolyte dissolver. Each electrolyte dissolver has a stirring device inside, an inlet at the top, and an outlet at the bottom. The outlet of the dissolver is connected to the inlet of the solid-liquid separator. The outlet of the solid-liquid separator is connected to the filter. The outlet of the filter is connected to the filtrate collection device. The outlet of the filtrate collection device is connected to the vacuum distillation device. This waste lithium-ion battery electrolyte recycling device utilizes organic solvents to dissolve the electrolyte and then performs solid-liquid separation, thereby separating the electrolyte from the electrode and separator materials in the waste lithium-ion battery, thus achieving the purpose of recycling each material separately.
[0005] A method for recycling waste lithium-ion battery electrolyte (patent publication number: CN104600392A) includes the following steps: 1) Dissecting the waste lithium-ion battery, removing the battery cells, and separating the battery cells in a centrifuge to obtain waste electrolyte; 2) Filtering, decolorizing, and dehydrating the obtained waste electrolyte; 3) Analyzing the composition of the dehydrated waste electrolyte, adding electrolyte and organic solvent to adjust it to the electrolyte composition ratio used in lithium-ion batteries, and producing an electrolyte product. This invention can realize the recycling and utilization of waste lithium battery electrolyte, avoiding environmental pollution from electrolyte, and is highly efficient and environmentally friendly. The recycled product can be returned to the lithium battery industry as electrolyte, saving resources and reducing pollution.
[0006] Existing publicly available technologies for recycling spent lithium-ion batteries mainly focus on electrode materials containing non-ferrous metals such as cobalt, lithium, nickel, and copper, which have high value. However, electrolytes are volatile and difficult to recycle, so there is little research and treatment specifically for electrolyte recycling. Furthermore, existing electrolyte recycling processes suffer from drawbacks such as low efficiency, high energy consumption, complex processes, and demanding equipment requirements, making them unsuitable for industrial-scale production.
[0007] Based on this, the present invention proposes a process for recycling electrolyte from retired lithium batteries. Summary of the Invention
[0008] In order to overcome the shortcomings of the prior art, this invention provides a process for recycling electrolyte from retired lithium batteries, which enables the reuse of electrolyte, saves production resources, and is environmentally friendly.
[0009] The objective of this invention is achieved through the following technical solution:
[0010] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0011] Step 1: According to the mass fraction, fully discharge 50-100 parts of retired lithium batteries and freeze them for 4-8 hours. Then disassemble the batteries to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse them in 200-300 parts of lithium hydroxide solution, add 0.5-3 parts of catalyst, stir and react for 1-2 hours, and filter to obtain filter residue.
[0012] Step 2: Add the filter residue to 450-600 parts of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 1-2 hours under an inert atmosphere, then add it to 800-1200 parts of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is completed, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0013] In some embodiments, the freezing temperature is -50 to -75°C.
[0014] In some embodiments, the concentration of the lithium hydroxide solution is 0.5-2 mol / L.
[0015] In some embodiments, the method for preparing the catalyst includes the following steps:
[0016] H1: By weight, take 32-64 parts of tetrapolyacryloylsuccinate disodium, 0.04-0.8 parts of lanthanum chloride and 300-400 parts of solvent, stir and mix the above raw materials, and react at a temperature of 30-40℃ for 50-100 minutes.
[0017] H2: Based on step H1, add 17-38 parts of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 2-5 parts of allylphenyl selenide and 4-7 parts of organic base, mix again, and then react at a temperature of 50-58℃ for 40-90 minutes; finally, remove the solvent in the system by rotary evaporation to obtain the desired catalyst.
[0018] In some embodiments, the organic base is selected from tripropylphosphine, dimethylphenylphosphine, methyldiphenylphosphine, and triphenylphosphine.
[0019] In some embodiments, the water bath temperature is 30-45°C, and the high-temperature calcination temperature is 600-800°C.
[0020] In some embodiments, the organic solvent is selected from one or more combinations of acetonitrile, dimethylformamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone.
[0021] In some embodiments, the inert atmosphere is at least one of nitrogen, argon, and helium.
[0022] In some embodiments, the reaction pressure is 400-600 kPa.
[0023] In some embodiments, the freeze-crystallization temperature is -45 to -20°C.
[0024] The beneficial effects achieved by the present invention using the above technical solution are as follows:
[0025] The tetrapropylene lanthanum succinate complex first undergoes a mercapto-olefin click reaction with 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride. The product then undergoes a second mercapto-olefin click reaction with allylphenylselenium to form the final catalyst. This catalyst may, during lithium battery waste treatment, activate reactants through coordination, electron transfer, and other means, thereby promoting the chemical reaction between lithium battery waste and lithium hydroxide solution. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with embodiments. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0028] Example 1
[0029] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0030] Step 1: After fully discharging 50g of retired lithium battery, freeze it for 4 hours. Then disassemble the battery to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse it in 200g of lithium hydroxide solution, add 0.5g of catalyst, stir and react for 1 hour, and filter to obtain filter residue.
[0031] Step 2: Add the filter residue to 450g of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 1 hour under an inert atmosphere, then add it to 800g of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is complete, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0032] The freezing temperature is -50°C.
[0033] The concentration of the lithium hydroxide solution is 0.5 mol / L.
[0034] The method for preparing the catalyst includes the following steps:
[0035] H1: Take 32g of tetrapolyacryloylsuccinate disodium, 0.04g of lanthanum chloride and 300g of solvent, stir and mix the above raw materials, and react at 30℃ for 50 minutes.
[0036] H2: Based on step H1, 17g of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 2g of allylphenyl selenide and 4g of organic base were added and mixed again. The mixture was then reacted at 50°C for 40 minutes. Finally, the solvent in the system was removed by rotary evaporation to obtain the desired catalyst.
[0037] The organic base is selected from tripropylphosphine.
[0038] The water bath temperature is 30℃, and the high-temperature calcination temperature is 600℃.
[0039] The organic solvent is selected from acetonitrile.
[0040] The inert atmosphere is nitrogen.
[0041] The reaction pressure is 400 kPa.
[0042] The freeze-crystallization temperature is -45℃.
[0043] Example 2
[0044] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0045] Step 1: After fully discharging 65g of retired lithium battery, freeze it for 5 hours. Then disassemble the battery to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse it in 235g of lithium hydroxide solution, add 1.5g of catalyst, stir and react for 1 hour, and filter to obtain filter residue.
[0046] Step 2: Add the filter residue to 500g of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 1 hour under an inert atmosphere, then add it to 900g of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is complete, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0047] The freezing temperature is -60°C.
[0048] The concentration of the lithium hydroxide solution is 1 mol / L.
[0049] The method for preparing the catalyst includes the following steps:
[0050] H1: Take 43g of tetrapolyacryloylsuccinate disodium, 0.25g of lanthanum chloride and 335g of solvent, stir and mix the above raw materials, and react at 35℃ for 65 minutes.
[0051] H2: Based on step H1, 24g of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 3.5g of allylphenyl selenide and 5g of organic base were added and mixed again. The mixture was then reacted at 52°C for 60 minutes. Finally, the solvent in the system was removed by rotary evaporation to obtain the desired catalyst.
[0052] The organic base is selected from dimethylphenylphosphine.
[0053] The water bath temperature is 35℃, and the high-temperature calcination temperature is 700℃.
[0054] The organic solvent is selected from dimethylformamide.
[0055] The inert atmosphere is argon.
[0056] The reaction pressure is 500 kPa.
[0057] The freeze-crystallization temperature is -35℃.
[0058] Example 3
[0059] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0060] Step 1: After fully discharging 85g of retired lithium battery, freeze it for 6.5h. Then disassemble the battery to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse it in 270g of lithium hydroxide solution, add 2.5g of catalyst, stir and react for 2h, and filter to obtain filter residue.
[0061] Step 2: Add the filter residue to 550g of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 2 hours under an inert atmosphere, then add it to 1050g of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is complete, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0062] The freezing temperature is -60°C.
[0063] The concentration of the lithium hydroxide solution is 1.5 mol / L.
[0064] The method for preparing the catalyst includes the following steps:
[0065] H1: Take 52g of tetrapolyacryloylsuccinate disodium, 0.55g of lanthanum chloride and 375g of solvent, stir and mix the above raw materials, and react at 35℃ for 80 minutes.
[0066] H2: Based on step H1, 31g of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 4.5g of allylphenyl selenide and 6g of organic base were added and mixed again. The mixture was then reacted at 56°C for 75 minutes. Finally, the solvent in the system was removed by rotary evaporation to obtain the desired catalyst.
[0067] The organic base is selected from methyldiphenylphosphine.
[0068] The water bath temperature is 40℃, and the high-temperature calcination temperature is 700℃.
[0069] The organic solvent is selected from dimethyl sulfoxide.
[0070] The inert atmosphere is nitrogen.
[0071] The reaction pressure is 500 kPa.
[0072] The freeze-crystallization temperature is -25℃.
[0073] Example 4
[0074] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0075] Step 1: After fully discharging 100g of retired lithium battery, freeze it for 8 hours. Then disassemble the battery to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse it in 300g of lithium hydroxide solution, add 3g of catalyst, stir and react for 2 hours, and filter to obtain filter residue.
[0076] Step 2: Add the filter residue to 600g of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 2h under an inert atmosphere, then add it to 1200g of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is complete, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0077] The freezing temperature is -75°C.
[0078] The concentration of the lithium hydroxide solution is 2 mol / L.
[0079] The method for preparing the catalyst includes the following steps:
[0080] H1: Take 64g of tetrapolyacryloylsuccinate disodium, 0.8g of lanthanum chloride and 400g of solvent, stir and mix the above raw materials, and react at 40℃ for 100 minutes.
[0081] H2: Based on step H1, 38g of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 5g of allylphenyl selenide and 7g of organic base were added and mixed again. The mixture was then reacted at 58°C for 90 minutes. Finally, the solvent in the system was removed by rotary evaporation to obtain the desired catalyst.
[0082] The organic base is selected from triphenylphosphine.
[0083] The water bath temperature is 45℃, and the high-temperature calcination temperature is 800℃.
[0084] The organic solvent is selected from 1,3-dimethyl-2-imidazolinone.
[0085] The inert atmosphere is helium.
[0086] The reaction pressure is 600 kPa.
[0087] The freeze-crystallization temperature is -20℃.
[0088] Comparative Example 1
[0089] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0090] Step 1: After fully discharging 50g of retired lithium battery, freeze it for 4 hours. Then disassemble the battery to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse it in 200g of lithium hydroxide solution, add 0.5g of catalyst, stir and react for 1 hour, and filter to obtain filter residue.
[0091] Step 2: Add the filter residue to 450g of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 1 hour under an inert atmosphere, then add it to 800g of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is complete, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0092] The freezing temperature is -50°C.
[0093] The concentration of the lithium hydroxide solution is 0.5 mol / L.
[0094] The method for preparing the catalyst includes the following steps:
[0095] H1: Take 32g of tetrapolyacrylamide disodium succinate and 300g of solvent, stir and mix the above raw materials, and react at 30℃ for 50 minutes.
[0096] H2: Based on step H1, 17g of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 2g of allylphenyl selenide and 4g of organic base were added and mixed again. The mixture was then reacted at 50°C for 40 minutes. Finally, the solvent in the system was removed by rotary evaporation to obtain the desired catalyst.
[0097] The organic base is selected from tripropylphosphine.
[0098] The water bath temperature is 30℃, and the high-temperature calcination temperature is 600℃.
[0099] The organic solvent is selected from acetonitrile.
[0100] The inert atmosphere is nitrogen.
[0101] The reaction pressure is 400 kPa.
[0102] The freeze-crystallization temperature is -45℃.
[0103] Comparative Example 2
[0104] A process for recycling electrolyte from retired lithium batteries, characterized by comprising the following steps:
[0105] Step 1: After fully discharging 50g of retired lithium battery, freeze it for 4 hours. Then disassemble the battery to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse it in 200g of lithium hydroxide solution, add 0.5g of catalyst, stir and react for 1 hour, and filter to obtain filter residue.
[0106] Step 2: Add the filter residue to 450g of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 1 hour under an inert atmosphere, then add it to 800g of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is complete, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate.
[0107] The freezing temperature is -50°C.
[0108] The concentration of the lithium hydroxide solution is 0.5 mol / L.
[0109] The method for preparing the catalyst includes the following steps:
[0110] H1: Take 32g of tetrapolyacryloylsuccinate disodium, 0.04g of lanthanum chloride and 300g of solvent, stir and mix the above raw materials, and react at 30℃ for 50 minutes.
[0111] H2: Based on step H1, add 2g allylphenyl selenide and 4g organic base, mix again, and then react at 50°C for 40 minutes; finally, remove the solvent from the system by rotary evaporation to obtain the desired catalyst.
[0112] The organic base is selected from tripropylphosphine.
[0113] The water bath temperature is 30℃, and the high-temperature calcination temperature is 600℃.
[0114] The organic solvent is selected from acetonitrile.
[0115] The inert atmosphere is nitrogen.
[0116] The reaction pressure is 400 kPa.
[0117] The freeze-crystallization temperature is -45℃.
[0118] The lithium hexafluorophosphate obtained in the above specific implementation scheme was tested according to "HG / T 4066-2015 Lithium Hexafluorophosphate Electrolyte", and the test results are as follows:
[0119]
[0120]
[0121] The test results above show that this method effectively improves the recovery efficiency of decommissioned electrolyte, and the recovered lithium hexafluorophosphate meets the requirements of the standard "HG / T 4066-2015 Lithium Hexafluorophosphate Electrolyte".
[0122] The present invention has been described above through specific embodiments and examples. However, these descriptions are merely illustrative and should not be construed as limiting the scope of protection of the present invention. Without departing from the spirit and scope of the present invention, those skilled in the art can make various improvements, modifications, or equivalent substitutions to the technical solutions and implementation methods of the present invention, and all such modifications and substitutions should fall within the scope of protection of the present invention.
Claims
1. A process for recycling electrolyte from retired lithium batteries, characterized in that, Includes the following steps: Step 1: According to the mass fraction, fully discharge 50-100 parts of retired lithium batteries and freeze them for 4-8 hours. Then disassemble the batteries to obtain solid positive electrode material, negative electrode material, electrolyte, separator and shell. Immerse them in 200-300 parts of lithium hydroxide solution, add 0.5-3 parts of catalyst, stir and react for 1-2 hours, and filter to obtain filter residue. Step 2: Add the filter residue to 450-600 parts of hydrofluoric acid solution, heat and stir in a water bath to recover HF, transfer the solid to a tube furnace, calcine at high temperature for 1-2 hours under an inert atmosphere, then add it to 800-1200 parts of organic solvent, introduce PF5 gas under an inert atmosphere to maintain a constant reaction pressure, remove the filter residue after the reaction is completed, freeze the filtrate to crystallize, and dry it under an inert atmosphere to obtain lithium hexafluorophosphate; The method for preparing the catalyst, Includes the following steps: H1: By weight, take 32-64 parts of tetrapolyacryloylsuccinate disodium, 0.04-0.8 parts of lanthanum chloride and 300-400 parts of solvent, stir and mix the above raw materials, and react at a temperature of 30-40℃ for 50-100 minutes. H2: Based on step H1, add 17-38 parts of 3-mercapto-N,N,N-trimethylpropane-1-ammonium chloride, 2-5 parts of allylphenyl selenide and 4-7 parts of organic base, mix again, and then react at a temperature of 50-58℃ for 40-90 minutes; finally, remove the solvent in the system by rotary evaporation to obtain the desired catalyst. The organic base is selected from tripropylphosphine, dimethylphenylphosphine, methyldiphenylphosphine, and triphenylphosphine.
2. The process for recycling electrolyte from decommissioned lithium batteries according to claim 1, characterized in that, The freezing temperature is -50 to -75°C.
3. The process for recycling electrolyte from retired lithium batteries according to claim 1, characterized in that, The concentration of the lithium hydroxide solution is 0.5-2 mol / L.
4. The process for recycling electrolyte from decommissioned lithium batteries according to claim 1, characterized in that, The water bath temperature is 30-45℃, and the high-temperature calcination temperature is 600-800℃.
5. The process for recycling electrolyte from decommissioned lithium batteries according to claim 1, characterized in that, The organic solvent is selected from one or more combinations of acetonitrile, dimethylformamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone.
6. The process for recycling electrolyte from decommissioned lithium batteries according to claim 1, characterized in that, The inert atmosphere is at least one of nitrogen, argon, and helium.
7. The process for recycling electrolyte from decommissioned lithium batteries according to claim 1, characterized in that, The reaction pressure is 400-600 kPa.
8. The process for recycling electrolyte from retired lithium batteries according to claim 1, characterized in that, The freeze-crystallization temperature is -45 to -20°C.