Recovery method of solid-state battery
By disassembling solid-state batteries in an inert gas environment and using ethanol and NMP solvents to separate the positive and negative electrode materials and sulfide electrolytes, the problem of toxic gas generation during solid-state battery recycling is solved, achieving efficient and safe resource recycling.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI LONGKAI PILOT PLATFORM CIRCULATION TECHNOLOGY CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-04-21
AI Technical Summary
In existing solid-state battery recycling processes, sulfide solid electrolytes produce toxic gases when they come into contact with water vapor, leading to high recycling difficulty and cost, and the safety hazards of liquid electrolytes have not been effectively addressed.
The battery is disassembled in an inert gas environment, the cell is crushed, and the positive and negative electrode materials and sulfide electrolyte are dissolved by ethanol and NMP solvents respectively. By precisely controlling the solid-liquid ratio, stirring rate and temperature, combined with gravity sedimentation separation, the NMC positive electrode material, graphite negative electrode material and sulfide solid electrolyte are efficiently recovered.
It achieves high recycling efficiency of 99% and 97% for NMC cathode materials and graphite anode materials, respectively, while recovering sulfide solid electrolyte, reducing production safety hazards and solvent waste, and meeting green recycling requirements.
Smart Images
Figure CN121906015A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of solid-state battery recycling technology, and specifically relates to a method for recycling solid-state batteries. Background Technology
[0002] The non-renewable nature and environmental pollution of chemical energy have led to increasing favor for efficient and clean electrochemical energy storage devices. Lithium-ion batteries have advantages such as high energy density, long lifespan, and low self-discharge, and have been widely used in wearable electronic devices. However, with the development of electric vehicles and other electronic devices, the requirements for lithium secondary batteries are becoming increasingly stringent. Currently, lithium-ion batteries mainly use liquid electrolytes, which contain a large amount of flammable organic solvents, posing serious safety hazards. Furthermore, they have a narrow electrochemical window, making it difficult to adapt to high-energy-density battery systems.
[0003] Therefore, the development of solid-state batteries is the key to the next generation of lithium batteries. At present, solid electrolytes mainly include polymer solid electrolytes, inorganic solid electrolytes and composite solid electrolytes. Among the inorganic solid electrolytes, oxide solid electrolytes have advantages such as high ionic conductivity, wide electrochemical window, high mechanical strength and easy manufacturing, and have broad application prospects.
[0004] Solid-state batteries offer better safety compared to liquid batteries, but they still have many problems that lead to battery failure. Existing solid-state batteries require the decomposition and recycling of the positive and negative electrode materials in the electrolyte during the recycling process. Since the sulfide solid electrolyte produces toxic gases when it comes into contact with water vapor during the recycling process, the requirements for battery recycling processing capacity are high, resulting in high recycling costs. Therefore, we need to propose a recycling method for solid-state batteries. Summary of the Invention
[0005] To address the above problems, this invention provides a method for recycling solid-state batteries, comprising the following steps:
[0006] Step 1: Discharge the recycled solid-state batteries;
[0007] Step 2: Disassemble the solid-state battery after discharge to separate the battery cells from the casing, and then crush the battery cells in an inert gas environment.
[0008] Step 3: Physically sort the pulverized battery cells to obtain black substances, which mainly consist of NMC positive electrode material, graphite negative electrode material, sulfide fragments, and PVDF binder residue.
[0009] Step 4: For the solid electrolyte containing sulfide (black substance), add ethanol solvent to dissolve it, heat and stir to dissolve the solid electrolyte into the solvent, the positive and negative electrode active materials precipitate at the bottom, and perform solid-liquid separation of the solvent to obtain the first liquid phase and the first solid phase.
[0010] Step 5: Add NMP solvent to the first solid phase and heat and stir to dissolve the binder in the first solid phase. Perform solid-liquid separation again to obtain a second liquid phase and a second solid phase. Add a medium to the second solid phase to separate the positive and negative electrode materials by gravity sedimentation.
[0011] Furthermore, in step 1, the voltage and internal resistance of the solid-state battery are detected to assess the remaining charge and state of the solid-state battery. The solid-state battery is then connected to an external discharge device to deplete its charge and reduce the battery voltage to an absolutely safe range.
[0012] Furthermore, in step 2, the solid-state battery casing, cables, battery management system, cooling system and mounting bracket are disassembled and sorted, and the individual cells in the solid-state battery are separated and crushed in an inert gas environment.
[0013] Furthermore, in step 3, the pulverized battery cells are initially separated according to particle size, and magnetic positive electrode materials containing nickel, cobalt and iron are separated by magnetic separation. Lightweight membrane fragments and plastics are separated by airflow separation, and non-ferrous metals, including aluminum foil and copper foil, are separated by eddy current separation.
[0014] Furthermore, in step 4, ethanol solvent is added to the black substance. The ethanol solvent is soaked through a molecular sieve for more than 48 hours to ensure that there is no water in the ethanol solvent. The solid-liquid ratio of the black substance to the ethanol solvent is 1:20-1:50. The stirring rate of the ethanol solvent and the black substance is 300-500 rpm, and the temperature is controlled at 25-40℃.
[0015] Furthermore, the reaction time between the black substance and the ethanol solvent is controlled at 60-90 min. After the reaction is completed, the centrifuge speed is controlled at 4000-6000 rpm and centrifuged for 15-20 min to separate the mixture of black substance and ethanol solvent into ethanol solvent containing dissolved SSE (first liquid phase) and a mixture of precipitated NMC positive electrode material, graphite negative electrode and binder (first solid phase).
[0016] Furthermore, in step 5, NMP solvent is added to the first solid phase. The NMP solvent is N-methylpyrrolidone. The solid-liquid ratio of the first solid phase to the NMP solvent is 1:30-1:40, and the stirring rate of the first solid phase and the NMP solvent is 400-600 rpm, with the temperature controlled at 80-85℃.
[0017] Furthermore, the reaction time of the first solid phase with the NMP solvent is 120-180 min. After the reaction is completed, the mixture is centrifuged for 20 min at a temperature of 70-80℃ and a speed of 5000 rpm to obtain an NMP solution containing PVDF binder (second liquid phase) and a pure NMC and graphite mixed powder (second solid phase).
[0018] Furthermore, the medium is deionized water, and a second solid phase is added to the deionized water. The solid-liquid ratio of the second solid phase to the deionized water is 1:100. The stirring rate is 100-200 rpm, and the mixture is allowed to stand at room temperature for 30-60 minutes. The upper layer consists of graphite particles, and the lower layer consists of NMC sediment. The graphite particles and NMC sediment are separated by decantation and then dried.
[0019] Furthermore, the first liquid phase is evaporated and condensed for recovery to obtain solid SSE residue. The second liquid phase is distilled, and the NMP fraction at 202°C is collected and dried to obtain solid NMC.
[0020] The beneficial effects of this invention are:
[0021] 1. This invention achieves a maximum recovery efficiency of 99% for NMC cathode material and 97% for graphite anode material by precisely controlling the solid-liquid ratio of ethanol and NMP, reaction temperature and stirring rate, combined with gravity sedimentation separation. It can also simultaneously recover sulfide solid electrolyte (SSE) and NMP solvent, thus realizing the efficient recycling of key resources.
[0022] 2. This invention reduces the battery voltage to a safe range through pretreatment stage discharge, and the cell crushing is carried out in an inert gas environment to avoid the risk of sulfide reaction with water or dust. There are no high-risk chemical reagents throughout the process, reducing production safety hazards. Ethanol and NMP solvent can be recovered and reused through evaporation and distillation, reducing solvent waste and waste liquid discharge. Moreover, the process has no heavy metal pollution links, which meets the industrial development needs of green recycling.
[0023] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 A schematic flowchart of the solid-state battery recycling method according to the present invention is shown. Detailed Implementation
[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] like Figure 1 As shown in the figure, this embodiment of the invention provides a method for recycling solid-state batteries, including the following steps:
[0028] Step 1: Discharge the recycled solid-state batteries;
[0029] Step 2: Disassemble the solid-state battery after discharge to separate the battery cells from the casing, and then crush the battery cells in an inert gas environment.
[0030] Step 3: Physically sort the pulverized battery cells to obtain black substances, which mainly consist of NMC positive electrode material, graphite negative electrode material, sulfide SSE fragments, and PVDF binder residue.
[0031] Step 4: For the solid electrolyte containing sulfides (black substance), add ethanol solvent to dissolve it. Anhydrous ethanol is used as the ethanol solvent because it has high solubility for sulfides (SSE) (such as Li6PS5Cl) (up to 50 mg / mL) and extremely low solubility for NMC, graphite, and PVDF. It is also relatively inexpensive and less toxic. Heating and stirring are used to dissolve the solid electrolyte in the solvent. The positive and negative electrode active materials precipitate at the bottom. The solvent is then subjected to solid-liquid separation to obtain the first liquid phase and the first solid phase.
[0032] Step 5: Add NMP solvent to the first solid phase and heat and stir to dissolve the binder in the first solid phase. Perform solid-liquid separation again to obtain a second liquid phase and a second solid phase. Add a medium to the second solid phase to separate the positive and negative electrode materials by gravity sedimentation.
[0033] In step 1, the voltage and internal resistance of the solid-state battery are tested to assess the remaining charge and state of the solid-state battery. The solid-state battery is then connected to an external discharge device to deplete its charge and reduce the battery voltage to an absolutely safe range.
[0034] In step 2, the solid-state battery casing, cables, battery management system, cooling system and mounting bracket are disassembled and sorted, and the individual cells in the solid-state battery are separated and crushed in an inert gas environment.
[0035] In step 3, the pulverized battery cells are initially separated according to particle size, and magnetic positive electrode materials containing nickel, cobalt and iron are separated by magnetic separation. Lightweight membrane fragments and plastics are separated by airflow separation, and non-ferrous metals, including aluminum foil and copper foil, are separated by eddy current separation.
[0036] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.
[0037] Let the mass of the black substance be m. Based on the solid-liquid ratio of the black substance to the ethanol solvent being 1:20-1:50, the required volume V of the ethanol solvent can be calculated. Let the mass of the first solid phase be m1. Based on the solid-liquid ratio of the first solid phase to the NMP solvent being 1:30-1:40, the required volume V1 of the NMP solvent can be calculated.
[0038] Example 1
[0039] The mass of the black substance is m=10g. According to the solid-liquid ratio of 1:20, V=10g×20=200mL.
[0040] Reaction steps: Add 10g of black substance to 200mL of anhydrous ethanol solvent that has been soaked in molecular sieve for more than 48h. Set the stirring speed to 300rpm, control the temperature at 25℃, and the reaction time to 60min. After the reaction is completed, pour the mixture into a centrifuge and centrifuge at 4000rpm for 15min to obtain an ethanol solvent containing dissolved SSE (first liquid phase) and a mixture of precipitated NMC positive electrode material, graphite negative electrode and binder (first solid phase).
[0041] The mass of the first solid phase is m1 = 5g. Based on the solid-liquid ratio of 1:30, V1 = 5g × 30 = 150mL.
[0042] Reaction steps: Add 5g of the first solid phase to 150mL of NMP solvent, set the stirring speed to 400rpm, control the temperature at 80℃, and the reaction time to 120min. After the reaction is completed, pour the mixture into a centrifuge and centrifuge at 70℃ and 5000rpm for 20min to obtain an NMP solution containing PVDF binder (second liquid phase) and a pure NMC and graphite mixed powder (second solid phase).
[0043] In step 4, ethanol solvent is added to the black substance. The ethanol solvent is soaked through a molecular sieve for more than 48 hours to ensure that there is no water in the ethanol solvent. The solid-liquid ratio of the black substance to the ethanol solvent is 1:20-1:50. The stirring rate of the ethanol solvent and the black substance is 300-500 rpm, and the temperature is controlled at 25-40℃.
[0044] The reaction time between the black substance and the ethanol solvent is controlled at 60-90 min. After the reaction is completed, the centrifuge speed is controlled at 4000-6000 rpm and centrifuged for 15-20 min to separate the mixture of black substance and ethanol solvent into ethanol solvent containing dissolved SSE (first liquid phase) and a mixture of precipitated NMC positive electrode material, graphite negative electrode and binder (first solid phase).
[0045] In step 5, NMP solvent, which is N-methylpyrrolidone, is added to the first solid phase. The solid-liquid ratio of the first solid phase to the NMP solvent is 1:30-1:40, and the stirring rate of the first solid phase and the NMP solvent is 400-600 rpm, with the temperature controlled at 80-85℃.
[0046] The reaction time of the first solid phase with NMP solvent is 120-180 min. After the reaction is completed, the mixture is centrifuged for 20 min at a temperature of 70-80℃ and a speed of 5000 rpm to obtain an NMP solution containing PVDF binder (second liquid phase) and a pure NMC and graphite mixed powder (second solid phase).
[0047] The medium is deionized water. A second solid phase is added to the deionized water. The solid-liquid ratio of the second solid phase to the deionized water is 1:100. The stirring rate is 100-200 rpm. The mixture is allowed to stand at room temperature for 30-60 minutes. The upper layer consists of graphite particles, and the lower layer consists of NMC sediment. The graphite particles and NMC sediment are separated by decantation and then dried.
[0048] The first liquid phase is evaporated and condensed for recovery. Ethanol is evaporated and condensed for recovery, resulting in a solid SSE residue. This residue can be washed with a small amount of ethanol, vacuum dried, and then directly used for resynthesis. The second liquid phase is distilled, and the NMP fraction at 202°C is collected. After drying, solid NMC is obtained. The recovered NMP has high purity and can be recycled. PVDF can be centrally processed.
[0049] Example 2
[0050] The rest is the same as in Example 1, except that the mass of the black substance is m=20g, and according to the solid-liquid ratio of 1:30, V=20g×30=600mL;
[0051] Reaction steps: 20g of black substance was placed in 600mL of anhydrous ethanol solvent, the stirring speed was adjusted to 400rpm, the temperature was maintained at 30℃, and the reaction time was 75min. After the reaction was completed, the mixture was centrifuged at 5000rpm for 18min to separate the first liquid phase and the first solid phase.
[0052] The rest is the same as in Example 1, except that the mass of the first solid phase m1 = 10g, and according to the solid-liquid ratio of 1:35, V1 = 10g × 35 = 350mL;
[0053] Reaction steps: 10g of the first solid phase was placed in 350mL of NMP solvent, the stirring speed was adjusted to 500rpm, the temperature was maintained at 82℃, and the reaction time was 150min. Then, the mixture was centrifuged to obtain the second liquid phase and the second solid phase.
[0054] Example 3
[0055] The rest is the same as in Example 1, except that the mass of the black substance is m=30g, and according to the solid-liquid ratio of 1:50, V=30g×50=1500mL;
[0056] Reaction steps: Add 30g of black substance to 1500mL of anhydrous ethanol solvent, set the stirring speed to 500rpm, control the temperature at 40℃, and the reaction time to 90min. After the reaction is completed, centrifuge at 6000rpm for 20min to obtain the first liquid phase and the first solid phase.
[0057] The rest is the same as in Example 1, except that the mass of the first solid phase m1 = 15g, and according to the solid-liquid ratio of 1:40, V1 = 15g × 40 = 600mL;
[0058] Reaction procedure: 15g of the first solid phase was added to 600mL of NMP solvent. The stirring rate was set to 600rpm, the temperature was controlled at 85℃, and the reaction time was 180min. After the reaction was completed, centrifugation was performed to obtain the second liquid phase and the second solid phase.
[0059] Because the density of NMC (approximately 4.8 g / cm³) is much greater than that of graphite (approximately 2.2 g / cm³), NMC completely sinks to the bottom during gravity settling with almost no loss; while graphite is prone to slight agglomeration due to its small particle size or PVDF residue, resulting in some of it settling with NMC, thus the efficiency is slightly lower.
[0060] Optimal, when the ethanol-to-liquid ratio in step 4 is ≥1:30, the NMP-to-liquid ratio in step 5 is ≥1:35, the reaction temperature is ≥30℃ (ethanol) / 80℃ (NMP), and the reaction time is ≥75min (ethanol) / 150min (NMP), the recovery efficiency of both materials can be stably maintained above 97%.
[0061] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for recycling solid-state batteries, characterized in that, Includes the following steps: Step 1: Discharge the recycled solid-state batteries; Step 2: Disassemble the solid-state battery after discharge to separate the battery cells from the casing, and then crush the battery cells in an inert gas environment. Step 3: Physically sort the pulverized battery cells to obtain black substances, which mainly consist of NMC positive electrode material, graphite negative electrode material, sulfide SSE fragments, and PVDF binder residue. Step 4: For solid electrolytes containing sulfides, add ethanol solvent to dissolve them, heat and stir to dissolve the solid electrolyte into the solvent, and the positive and negative electrode active materials precipitate at the bottom. Separate the solvent into solid and liquid phases to obtain the first liquid phase and the first solid phase. Step 5: Add NMP solvent to the first solid phase and heat and stir to dissolve the binder in the first solid phase. Perform solid-liquid separation again to obtain a second liquid phase and a second solid phase. Add a medium to the second solid phase to separate the positive and negative electrode materials by gravity sedimentation.
2. The method for recycling solid-state batteries according to claim 1, characterized in that: In step 1, the voltage and internal resistance of the solid-state battery are tested to assess the remaining charge and state of the solid-state battery. The solid-state battery is then connected to an external discharge device to deplete its charge and reduce the battery voltage to an absolutely safe range.
3. The method for recycling solid-state batteries according to claim 2, characterized in that: In step 2, the solid-state battery casing, cables, battery management system, cooling system and mounting bracket are disassembled and sorted, and the individual cells in the solid-state battery are separated and crushed in an inert gas environment.
4. The method for recycling solid-state batteries according to claim 3, characterized in that: In step 3, the pulverized battery cells are initially separated according to particle size, and magnetic positive electrode materials containing nickel, cobalt and iron are separated by magnetic separation. Lightweight membrane fragments and plastics are separated by airflow separation, and non-ferrous metals, including aluminum foil and copper foil, are separated by eddy current separation.
5. The method for recycling solid-state batteries according to claim 4, characterized in that: In step 4, ethanol solvent is added to the black substance. The ethanol solvent is soaked through a molecular sieve for more than 48 hours to ensure that there is no water in the ethanol solvent. The solid-liquid ratio of the black substance to the ethanol solvent is 1:20-1:
50. The stirring rate of the ethanol solvent and the black substance is 300-500 rpm, and the temperature is controlled at 25-40℃.
6. The method for recycling solid-state batteries according to claim 5, characterized in that: The reaction time between the black substance and the ethanol solvent is controlled at 60-90 min. After the reaction is completed, the centrifuge speed is controlled at 4000-6000 rpm and centrifuged for 15-20 min to separate the mixture of black substance and ethanol solvent into a mixture containing dissolved SSE ethanol solvent and precipitated NMC positive electrode material, graphite negative electrode and binder.
7. The method for recycling solid-state batteries according to claim 6, characterized in that: In step 5, NMP solvent, which is N-methylpyrrolidone, is added to the first solid phase. The solid-liquid ratio of the first solid phase to the NMP solvent is 1:30-1:40, and the stirring rate of the first solid phase and the NMP solvent is 400-600 rpm, with the temperature controlled at 80-85℃.
8. A method for recycling solid-state batteries according to claim 7, characterized in that: The reaction time of the first solid phase with NMP solvent is 120-180 min. After the reaction is completed, the mixture is centrifuged for 20 min at a temperature of 70-80℃ and a speed of 5000 rpm to obtain an NMP solution containing PVDF binder and a pure NMC and graphite mixed powder.
9. A method for recycling solid-state batteries according to claim 8, characterized in that: The medium is deionized water. A second solid phase is added to the deionized water. The solid-liquid ratio of the second solid phase to the deionized water is 1:
100. The stirring rate is 100-200 rpm. The mixture is allowed to stand at room temperature for 30-60 minutes. The upper layer consists of graphite particles, and the lower layer consists of NMC sediment. The graphite particles and NMC sediment are separated by decantation and then dried.
10. A method for recycling solid-state batteries according to claim 9, characterized in that: The first liquid phase was evaporated and condensed to recover the solid SSE residue. The second liquid phase was distilled and the NMP fraction at 202°C was collected. After drying, NMC solid was obtained.