A composite high-efficiency external discharge method for waste batteries
By combining external discharge circuits, magnetohydrodynamics, and ultrasound, the problems of corrosion and slow mass transfer rate during the discharge process of waste batteries are solved, achieving efficient and corrosion-free battery discharge, and ensuring battery safety and complete discharge.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INST OF ENERGY HEFEI COMPREHENSIVE NAT SCI CENT (ANHUI ENERGY LAB)
- Filing Date
- 2026-03-05
- Publication Date
- 2026-06-09
AI Technical Summary
In existing technologies, waste batteries are prone to corrosion during discharge, and traditional static solutions have limited ion mass transfer rates and severe concentration polarization, resulting in slow and unstable discharge speeds.
An external discharge circuit structure is adopted, which uses graphite electrodes to connect with waste batteries. By adding magnetic fluid to the discharge solution and applying an external magnetic field to drive its circulation, and combining it with ultrasonic treatment, a dynamic mass transfer environment is constructed to avoid contact between the battery and the solution and enhance ion transfer.
It achieves corrosion-free and efficient discharge, significantly accelerates the discharge rate, ensures the complete release of internal charge in the battery, avoids the risk of subsequent secondary discharge, and provides a safe and reliable discharge process.
Smart Images
Figure CN121769310B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of waste battery recycling technology, and in particular to a composite high-efficiency external discharge method for waste batteries. Background Technology
[0002] With the rapid development of the new energy vehicle and consumer electronics industries, the number of waste lithium-ion batteries has increased dramatically, making their safe recycling and resource utilization a critical issue that urgently needs to be addressed. Deep discharging batteries that still contain residual charge before recycling is an indispensable pretreatment step to eliminate the risks of short circuits, fires, and even explosions during subsequent crushing and sorting processes.
[0003] Currently, mainstream discharge methods are mainly divided into physical discharge and chemical discharge. Physical discharge is direct in operation, but the heat generated during discharge is concentrated, posing a significant risk of thermal runaway. While chemical discharge can achieve discharge, the strong electrolyte solution severely corrodes the battery casing and electrodes, leading to electrolyte leakage and secondary environmental pollution. It also increases impurity interference and cost burden for subsequent hydrometallurgical recovery. To overcome the problem of direct battery corrosion, existing technologies have proposed external solution discharge, which involves connecting the battery electrodes to electrodes immersed in the discharge solution via wires, thus isolating the battery body from the solution. Although this method protects the battery, the metal wires, which serve as the conductive path, are immersed in the electrolyte for a long time, and they themselves undergo electrochemical corrosion, resulting in decreased conductivity, increased contact resistance, and consequently affecting discharge efficiency and stability, or even causing discharge interruption. In addition, the ion mass transfer rate of traditional static solutions is limited, and concentration polarization is severe, further restricting the discharge rate. Summary of the Invention
[0004] This invention provides a composite high-efficiency external discharge method for waste batteries, which can solve the problems in the prior art where batteries and conductive paths are easily corroded, and the ion mass transfer rate of traditional static solutions is limited and concentration polarization is severe, which further restricts the discharge speed.
[0005] A composite high-efficiency external discharge method for waste batteries includes the following steps: S1, preparing a discharge solution and adding a magnetic fluid to the discharge solution; S2, connecting the waste battery to a graphite electrode via a wire to form an external discharge circuit; S3, immersing the graphite electrode in the discharge solution, maintaining a predetermined distance between adjacent graphite electrodes; S4, applying an external magnetic field to the discharge solution to drive the flow of the magnetic fluid therein; S5, discharging through the external discharge circuit and monitoring the voltage of the waste battery in real time until it drops below a safe threshold, at which point discharging is stopped and the battery is removed.
[0006] The present invention provides a composite high-efficiency external discharge method for waste batteries, which, compared with the prior art, has the following beneficial effects, but is not limited to:
[0007] This composite high-efficiency external discharge method for waste batteries employs an external discharge circuit structure where waste batteries are connected to graphite electrodes via wires. This ensures that the battery body is completely isolated from the discharge solution. Furthermore, the graphite electrodes are highly corrosion-resistant, and the wires only serve as external conductors without contacting the solution. This fundamentally eliminates the problem of easy corrosion of the battery casing, tabs, and conductive paths by the discharge solution, and avoids interference from corrosion products with subsequent processes. Simultaneously, compared to traditional static solution discharge methods, the addition of a magnetic fluid to the discharge solution and the application of an external magnetic field can actively drive the solution to form a forced circulation flow. This dynamic environment significantly accelerates the migration and diffusion rate of ions within the solution, effectively breaking the static diffusion layer formed on the electrode surface due to ion consumption. This greatly alleviates concentration polarization and overcomes the discharge speed bottleneck caused by low ion mass transfer rates and severe concentration polarization in traditional static solutions, achieving a highly efficient and corrosion-free discharge effect.
[0008] Further, in step S4, ultrasound is applied to the discharge solution.
[0009] Further, in step S1, the discharge solution is a composite aqueous solution of one or more of the following: sodium chloride, potassium chloride, sodium sulfate, copper sulfate, potassium nitrate, lithium nitrate, citric acid, or sodium thiosulfate, with a concentration of 10% to 25%.
[0010] Further, in step S1, the magnetic fluid is one or more of Fe, Ni, Co, Fe3O4, and γ-Fe2O3, and the volume ratio of the magnetic fluid to the discharge solution is 5% to 10%.
[0011] Furthermore, in step S2, the wire is a copper wire with alligator clips, which are used to hold the tabs of the used battery.
[0012] Further, in step S2, the graphite electrode includes a first graphite electrode and a second graphite electrode, and the distance between the first graphite electrode and the second graphite electrode is 1cm to 6cm.
[0013] Furthermore, in step S4, the applied external magnetic field strength is 50mT~200mT.
[0014] Furthermore, the ultrasound is applied by an ultrasound probe inserted into the discharge solution, and the ultrasound power is 300W~800W.
[0015] Furthermore, in step S5, the voltage is monitored in real time using a multimeter connected between the two tabs of the used battery.
[0016] Furthermore, in step S2, the waste battery is a waste lithium-ion battery. Attached Figure Description
[0017] Figure 1 This is a flowchart of a composite high-efficiency external discharge method for waste batteries according to an embodiment of the present invention;
[0018] Figure 2 The graphs show the battery voltage variation over time during the battery discharge process in three embodiments of the present invention. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings showing multiple embodiments according to this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.
[0020] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," etc., in the description, claims, and accompanying drawings of this application are open-ended terms. Therefore, "comprising," "including," or "having" refers to, for example, a method or apparatus having one or more steps or elements, but is not limited to having only these one or more elements. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0021] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0022] Example 1:
[0023] like Figure 1 As shown in the figure, an embodiment of the present invention provides a composite high-efficiency external discharge method for waste batteries, comprising the following steps: S1, preparing a discharge solution and adding a magnetic fluid to the discharge solution; S2, connecting the waste battery to a graphite electrode via a wire to form an external discharge circuit; S3, immersing the graphite electrode in the discharge solution, maintaining a predetermined distance between the two graphite electrodes; S4, applying an external magnetic field to the discharge solution to drive the flow of the magnetic fluid therein; S5, discharging through the external discharge circuit and monitoring the voltage of the waste battery in real time until it drops below a safe threshold, at which point discharging is stopped and the battery is removed.
[0024] In this embodiment, an external discharge circuit structure is adopted, in which waste batteries are connected to graphite electrodes via wires. This ensures that the battery body is completely isolated from the discharge solution. Furthermore, the graphite electrodes are highly corrosion-resistant, and the wires only serve as external conductors without contacting the solution. This fundamentally eliminates the problem of easy corrosion of the battery casing, tabs, and conductive paths by the discharge solution, and avoids interference from corrosion products with subsequent processes. At the same time, compared with the traditional static solution discharge method, the addition of magnetic fluid to the discharge solution and the application of an external magnetic field can actively drive the solution to form a forced circulation flow. This dynamic environment significantly accelerates the migration and diffusion rate of ions inside the solution, effectively breaking the static diffusion layer formed on the electrode surface due to ion consumption. This greatly alleviates the concentration polarization phenomenon and overcomes the discharge speed bottleneck caused by the low ion mass transfer rate and severe concentration polarization of traditional static solutions, achieving a highly efficient and corrosion-free discharge effect.
[0025] Specifically, if only an external discharge circuit structure is used, the discharge solution is in a static state, the ion mass transfer rate is limited, and the concentration gradient is easily formed near the electrode due to the consumption of ions by the reaction, resulting in prominent concentration polarization. This makes it difficult to completely release the residual charge inside the battery through a single external discharge. In particular, the residual charge in the pore structure inside the waste battery cannot be fully contacted and conducted out by ions in the static solution, which may require the battery to be directly immersed in the solution for a second discharge to remove the residual charge.
[0026] This solution employs a combined design of an external discharge circuit, a discharge solution with magnetofluid, and an applied external magnetic field. The external magnetic field drives the magnetofluid to circulate rapidly within the solution. On one hand, this overcomes the limitations of ion mass transfer in static solutions, accelerating overall ion diffusion and effectively mitigating concentration polarization. This allows ions to react more efficiently with the graphite electrode, enhancing charge conduction efficiency. On the other hand, the circulating flow of the magnetofluid creates dynamic disturbances, causing the solution to penetrate into the micro-area surrounding the electrode, fully contacting and discharging the charge transferred by the battery through the external circuit. Simultaneously, it works in conjunction with the external discharge circuit to isolate and protect the battery from the solution, preventing corrosion. Through the synergistic effect of dynamically enhanced mass transfer and the external discharge circuit, the internal charge of the battery can be completely released in a single discharge, eliminating the need for any subsequent secondary discharges.
[0027] By adding a magnetofluid to the discharge solution and applying an external magnetic field, the magnetofluid is driven to form a forced circulation flow, thereby constructing an active "ion transport pump" in the solution. This directional flow not only powerfully scours the electrode surface and continuously and rapidly updates the ion concentration at the electrode-solution interface, thus breaking the diffusion limitations of traditional static solutions and effectively suppressing concentration polarization, allowing the discharge process to continue under high ion flux and significantly shortening the discharge time; at the same time, this uniform and enhanced mass transfer ensures the depth and thoroughness of the discharge reaction, stabilizing the battery voltage to a safe threshold of 0.1V or below, minimizing the risk of residual charge due to incomplete discharge, and providing a safety guarantee for subsequent disassembly.
[0028] The magnetic fluid is one or more of Fe, Ni, Co, Fe3O4, and γ-Fe2O3.
[0029] In step S4, ultrasonic waves are applied to the discharge solution by inserting an ultrasonic probe into the discharge solution.
[0030] In this embodiment, after inserting the ultrasonic probe into the discharge solution with the discharge circuit already connected, the mechanical vibration generated by the high-power ultrasound can transfer high-frequency kinetic energy to the solution, breaking the kinetic barrier of ion diffusion, accelerating the migration and mixing rate of ions in the discharge solution, effectively compensating for the local limitations of mass transfer in a single magnetohydrodynamic circulation, further improving the overall ion mass transfer efficiency, alleviating the inhibition of the discharge reaction by concentration polarization, and providing a more sufficient ion supply for the electrochemical reaction on the electrode surface. Simultaneously, the cavitation effect induced by ultrasound can form a large number of microbubbles in the solution. The instantaneous high pressure and impact force generated when the bubbles burst can precisely remove impurities attached to the graphite electrode surface, byproducts generated by the discharge reaction, and membrane pore blockages, preventing such substances from covering the electrode active sites, increasing contact resistance, continuously maintaining the electrode's excellent conductivity and reactivity, and preventing electrode passivation leading to a decrease in the discharge rate. Furthermore, ultrasonic vibration can also assist in stirring the discharge solution, promoting a more uniform dynamic flow field formed by the magnetohydrodynamic circulation, further optimizing ion distribution, ensuring the continuous and efficient conduction of the discharge reaction, and ultimately, in synergy with the magnetohydrodynamic and magnetic field systems, achieving a significant increase in the discharge rate and the goal of complete de-energization in a single discharge.
[0031] Specifically, the high-frequency mechanical vibrations and cavitation microjets generated by ultrasound violently disturb the magnetofluid and its surrounding ions at the microscale. This not only directly accelerates ion diffusion but also significantly enhances the dispersibility of the magnetofluid nanoparticles and their interaction with the solution, making the macroscopic circulation flow driven by the magnetic field more efficient and uniform. Simultaneously, the directional traction effect of the external magnetic field on the magnetofluid provides macroscopic guidance and kinetic energy for the ultrasound-induced microflow, preventing the disordered dissipation of ultrasonic energy in the solution and making solution mixing and electrode surface scouring more targeted. Through the close coordination of "magnetic field directional flow guidance" and "ultrasound micro-activation," a complete enhanced mass transfer chain is constructed from macroscopic circulation to microscopic mass transfer. This results in ion migration, interface renewal, and product removal efficiencies far exceeding those of a single physical field or the simple superposition of both, thereby fundamentally and thoroughly suppressing concentration polarization and achieving simultaneous breakthroughs in discharge rate and depth.
[0032] The external discharge circuit, through its core design of connecting graphite electrodes to spent batteries, completely isolates the battery body from the discharge solution, avoiding the risk of corrosion to the battery and conductive paths. It also provides a stable pathway for charge conduction, ensuring efficient transfer of battery charge to the graphite electrode via wires. An external magnetic field drives magnetohydrodynamic circulation, forming a directional macroscopic flow field that breaks down the static solution mass transfer barrier, accelerating overall ion diffusion and uniform distribution. This provides ample ion supply for the electrochemical reactions on the graphite electrode surface, enhancing the charge conduction efficiency of the external discharge circuit. Ultrasonic waves, through high-frequency mechanical vibration and cavitation effects, enhance localized microscopic mass transfer, compensating for the limitations of the magnetohydrodynamic macroscopic circulation in the small areas around the electrode and in solution dead zones. This further alleviates concentration polarization, removes impurities and reaction byproducts from the electrode surface, maintains electrode activity, prevents electrode passivation leading to decreased circuit conduction efficiency, and breaks up slight agglomerations of the magnetohydrodynamic fluid, ensuring efficient transmission of the magnetic field driving force. With the combination of the three, the external discharge circuit ensures the safety and stability of charge conduction. The ultrasonic, magnetohydrodynamic and magnetic field system not only solves the problems of slow ion mass transfer and low discharge efficiency of a single external discharge circuit, but also makes up for the shortcomings of ultrasonic or magnetohydrodynamic and magnetic field technologies when used alone, which lack a safe and stable charge conduction path. Ultimately, it achieves a discharge effect with shorter discharge time, lower risk of residual charge, no corrosion and continuous stability. The synergistic gain far exceeds the simple sum of the effects of the three technologies.
[0033] In this embodiment, a used ternary lithium battery with an open-circuit voltage of 3.68V is selected. Prepare the discharge solution by using deionized water to prepare a 10% sodium chloride + 10% copper sulfate composite solution, and add 5% Fe3O4 magnetic fluid by volume to the discharge solution. Connect one end of the wire to the positive and negative tabs of the waste ternary lithium battery using alligator clips, and connect the other end to the first and second graphite electrodes, ensuring a firm connection and a good conductive path. At this point, the battery is not in contact with any solution. Place the external first and second graphite electrodes into a container containing the discharge solution, adjusting the distance between the first and second graphite electrodes to 6 cm. Fix multiple waste lithium-ion batteries on a battery stand to form a discharge circuit. Insert an ultrasonic probe into the container containing the discharge solution, set the ultrasonic power to 300 W, and simultaneously apply an external magnetic field with a magnetic field strength of 50 mT to drive the magnetic fluid circulation. Monitor the voltage of the waste lithium-ion batteries to be discharged in real time using a multimeter, and start the discharge. When the battery voltage drops to the safe dismantling voltage of 0.1 V or below, stop the discharge, turn off the ultrasonic and magnetic field equipment, remove the waste lithium-ion batteries, and the discharge process is complete.
[0034] During discharge, the battery voltage exhibited a continuous and stable downward trend without any sudden drops or stagnation. The initial voltage was 3.68V, gradually decreasing over time. From 1 to 28 minutes, the voltage successively dropped to 3.5312V, 3.3781V, and finally 0.1325V. It took only 29 minutes to reduce the voltage to 0.0612V, meeting the safe dismantling standard of 0.1V or below, demonstrating a stable and controllable discharge rate. This result fully verifies the synergistic effect of ultrasonic vibration, magnetic field-driven magnetohydrodynamic circulation, and the external discharge circuit. It not only accelerates the discharge process through dynamic mass transfer enhancement but also ensures complete discharge without residual charge risks. Furthermore, the entire process showed no corrosion of the battery casing, electrodes, or conductive paths, providing a reliable guarantee for the safe dismantling and recycling of subsequent used batteries.
[0035] Example 2:
[0036] The main difference between this embodiment and Embodiment 1 is that a used ternary lithium battery with an open-circuit voltage of 3.72V is selected. Prepare the discharge solution by using deionized water to prepare a 20% potassium chloride + 20% potassium nitrate composite solution, and add 5% Fe3O4 magnetic fluid by volume to the discharge solution. Connect one end of the wire to the positive and negative tabs of the waste ternary lithium battery using alligator clips, and connect the other end to the first and second graphite electrodes, ensuring a firm connection and a good conductive path. At this point, the battery is not in contact with any solution. Place the external first and second graphite electrodes into the container containing the discharge solution, adjusting the distance between the first and second graphite electrodes to 4 cm. Fix the waste lithium-ion battery on the battery stand to form a discharge circuit. Insert the ultrasonic probe into the container containing the discharge solution, set the ultrasonic power to 600W, and simultaneously apply an external magnetic field with a magnetic field strength of 100mT to drive the magnetic fluid circulation. Monitor the voltage of the waste lithium-ion battery to be discharged in real time using a multimeter, and start the discharge. When the battery voltage drops to the safe dismantling voltage of 0.1V or below, stop the discharge, turn off the ultrasonic and magnetic field equipment, remove the waste lithium-ion battery, and the discharge process is complete.
[0037] In this mixed solution containing 20% potassium chloride and 20% potassium nitrate, the voltage changes over time are as follows: initial (0 minutes) voltage 3.7812V, followed by 3.5441V at 1 minute, 3.4071V at 2 minutes, 3.2635V at 3 minutes, 3.1873V at 4 minutes, 2.9817V at 5 minutes, 2.789V at 6 minutes, 2.5838V at 7 minutes, 2.3878V at 8 minutes, 2.1726V at 9 minutes, 1.9789V at 10 minutes, 1.7767V at 11 minutes, and 1.576V at 12 minutes. The voltage levels were as follows: 13 minutes: 1.3767V; 14 minutes: 1.1765V; 15 minutes: 0.9667V; 16 minutes: 0.7759V; 17 minutes: 0.5598V; 18 minutes: 0.3797V; 19 minutes: 0.1788V; 20 minutes: 0.1685V; 21 minutes: 0.1566V; 22 minutes: 0.1451V; 23 minutes: 0.1356V; 24 minutes: 0.1221V; 25 minutes: 0.1112V; 26 minutes: 0.0967V. After 26 minutes, the battery voltage dropped to the safe disassembly voltage of 0.1V or below.
[0038] In this embodiment, the initial battery voltage during discharge was 3.7812V, showing a continuous and stable downward trend without voltage fluctuations or stagnation. From 1 to 25 minutes, the voltage gradually decreased from 3.5441V to 0.1112V, and it took only 26 minutes to reduce the battery voltage to 0.0967V, reaching the safe disassembly voltage standard of 0.1V or below. Compared to Embodiment 1, with a higher initial battery voltage, the discharge completion time was shortened by 3 minutes, and the discharge rate was significantly improved. The discharge effect of this embodiment fully demonstrates that the high-concentration composite discharge solution can provide more sufficient ion carriers, reducing the electrode spacing can shorten the ion migration path and enhance the electric field driving force, and increasing the ultrasonic power and magnetic field strength can further enhance ion mass transfer efficiency and alleviate concentration polarization. With the optimization of various parameters and the synergistic effect of ultrasound, magnetic field, and magnetohydrodynamics, the discharge system of this invention can achieve a faster discharge rate and a stable discharge process, with no battery or conductive path corrosion or discharge anomalies throughout the process. While ensuring complete discharge and eliminating the risk of residual charge, it further improves discharge efficiency, meeting the needs of efficient industrial processing.
[0039] Example 3
[0040] The main difference between this embodiment and Embodiment 1 is that a used ternary lithium battery with an open-circuit voltage of 3.78V is selected. Prepare the discharge solution by using deionized water to prepare a 25% ammonium chloride + 25% copper sulfate composite solution, and add 10% Fe3O4 magnetic fluid by volume to the discharge solution. Connect one end of the wire to the positive and negative tabs of the waste ternary lithium battery using alligator clips, and connect the other end to the first and second graphite electrodes, ensuring a firm connection and a good conductive path. At this point, the battery is not in contact with any solution. Place the external first and second graphite electrodes into a container containing the discharge solution, adjusting the distance between the first and second graphite electrodes to 2 cm. Fix the waste lithium-ion battery on a battery stand to form a discharge circuit. Insert an ultrasonic probe into the container containing the discharge solution, set the ultrasonic power to 800W, and simultaneously apply an external magnetic field with a magnetic field strength of 200mT to drive the magnetic fluid circulation. Monitor the voltage of the waste lithium-ion battery to be discharged in real time using a multimeter, and start the discharge. When the battery voltage drops to the safe dismantling voltage of 0.1V or below, stop the discharge, turn off the ultrasonic and magnetic field equipment, remove the waste lithium-ion battery, and the discharge process is complete.
[0041] In a mixed solution containing 25% ammonium chloride and 25% sodium chloride, the voltage variation over time is as follows: Initially (0 minutes), the voltage was 3.7185V, then decreased sequentially to 3.4688V at 1 minute, 3.2167V at 2 minutes, 2.9699V at 3 minutes, 2.7211V at 4 minutes, 2.4698V at 5 minutes, 2.2223V at 6 minutes, 1.9685V at 7 minutes, and 1.716V at 8 minutes. 7V, 9 minutes 1.469V, 10 minutes 1.2256V, 11 minutes 1.1145V, 12 minutes 1.0034V, 13 minutes 0.8545V, 14 minutes 0.5234V, 15 minutes 0.3937V, 16 minutes 0.2734V, 17 minutes 0.1556V, 18 minutes 0.0478V. At 18 minutes, the battery voltage drops to the safe disassembly voltage of 0.1V or below.
[0042] In this embodiment, the battery's initial monitoring voltage during discharge was 3.7185V. The voltage showed a rapid and stable downward trend without any fluctuations or stagnation. From 1 to 17 minutes, the voltage gradually decreased from 3.4688V to 0.1556V. It only took 18 minutes to reduce the battery voltage to 0.0478V, which is far below the safe disassembly voltage standard of 0.1V. Compared with Embodiment 1 and Embodiment 2, which had lower initial voltages, the discharge completion time was significantly shortened by 11 minutes and 8 minutes, respectively, and the discharge rate was significantly improved. The excellent discharge effect of this embodiment fully demonstrates that further increasing the concentration of the discharge solution can provide more sufficient ion carriers, increasing the proportion of magnetic fluid can enhance the mass transfer effect of solution circulation driven by the magnetic field, significantly reducing the electrode spacing can significantly shorten the ion migration path and strengthen the electric field driving force, and increasing the ultrasonic power and magnetic field strength can further amplify the ion mass transfer enhancement effect of mechanical vibration and the electrode activity maintenance effect of cavitation effect. Under the extreme optimization of each parameter and the deep synergistic effect of ultrasonic vibration, magnetic field driven magnetic fluid circulation and external discharge circuit, the discharge system of the present invention breaks through the dual bottlenecks of mass transfer and reaction rate, realizes ultra-fast, non-corrosive and complete de-energization of waste ternary lithium batteries, and the entire discharge process is stable and controllable with no residual charge risk, which fully verifies the wide range of process parameter controllability and the feasibility of large-scale and efficient industrial processing of the present invention.
[0043] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A composite high-efficiency external discharge method for waste batteries, characterized in that, Includes the following steps: S1. Prepare the discharge solution and add magnetic fluid to the discharge solution; S2. Connect the used battery to the graphite electrode through a wire to form an external discharge circuit; S3. Immerse the graphite electrode in the discharge solution, and maintain a predetermined distance between adjacent graphite electrodes. S4. Apply an external magnetic field to the discharge solution to drive the magnetohydrodynamic flow within it; S5. Discharge through an external discharge circuit and monitor the voltage of the used battery in real time until it drops below the safety threshold, then stop discharging and remove the battery. In step S4, ultrasound is applied to the discharge solution; In step S1, the discharge solution is a composite aqueous solution of one or more of the following: sodium chloride, potassium chloride, sodium sulfate, copper sulfate, potassium nitrate, lithium nitrate, citric acid, and sodium thiosulfate, with a concentration of 10% to 25%. The magnetic fluid is one or more of Fe, Ni, Co, Fe3O4, and γ-Fe2O3, and the volume ratio of the magnetic fluid to the discharge solution is 5% to 10%.
2. The composite high-efficiency external discharge method for waste batteries as described in claim 1, characterized in that, In step S2, the wire is a copper wire with alligator clips, which are used to hold the tabs of the used battery.
3. The composite high-efficiency external discharge method for waste batteries as described in claim 1, characterized in that, In step S2, the graphite electrode includes a first graphite electrode and a second graphite electrode, and the distance between the first graphite electrode and the second graphite electrode is 1cm to 6cm.
4. The composite high-efficiency external discharge method for waste batteries as described in claim 1, characterized in that, In step S4, the applied external magnetic field strength is 50mT~200mT.
5. The composite high-efficiency external discharge method for waste batteries as described in claim 2, characterized in that, The ultrasound is applied by an ultrasound probe inserted into the discharge solution, and the ultrasound power is 300W~800W.
6. The composite high-efficiency external discharge method for waste batteries as described in claim 1, characterized in that, In step S5, the voltage is monitored in real time using a multimeter connected between the two tabs of the used battery.
7. The composite high-efficiency external discharge method for waste batteries as described in claim 1, characterized in that, In step S2, the waste battery is a waste lithium-ion battery.