A kind of waste lithium ion battery fast discharge device and method

Abstract

The present invention discloses a device and method for rapid discharge of waste lithium-ion batteries, and belongs to the field of resource utilization of retired lithium-ion batteries. The present invention uses a mixed sulfate or chloride solution as a discharge medium, immerses the waste lithium-ion batteries therein, and realizes discharge by utilizing the directional movement of electrons formed by the external short-circuit principle. Since the battery is in the discharge solution, thermal runaway of the battery will not occur, and there is no obvious corrosion of the battery after discharge, and there is basically no leakage of the electrolyte in the battery. Fully automated equipment is used to discharge it safely and efficiently, and the wastewater and waste gas generated during the discharge process are treated accordingly to realize the recycling of wastewater. The equipment of the present invention can effectively improve the discharge efficiency, reduce the metal loss of the battery, and at the same time reduce environmental pollution, so as to ensure the subsequent safe treatment and disposal of waste lithium-ion batteries.

Description

Technical Field

[0001] The present invention relates to the field of resource utilization of retired lithium-ion batteries, and in particular to a device and method for quickly discharging waste lithium-ion batteries. Background Art

[0002] With the widespread use of lithium-ion batteries, the problem of waste lithium-ion battery management has gradually emerged. The harmful substances contained in waste lithium-ion batteries pose potential risks to the environment and human health. According to statistics, millions of tons of waste lithium-ion batteries are generated worldwide every year, including discarded batteries from consumer electronic devices and electric vehicles. Effective recycling and treatment of waste batteries has become crucial. As of now, the global recycling rate of waste lithium-ion batteries is still relatively low, about 5% to 10%. Improving the recycling rate of waste batteries, developing environmentally friendly treatment technologies, and establishing a more stringent waste battery management system have become urgent tasks to deal with the problem of waste lithium-ion batteries. Before the separation of the various metal components of lithium batteries, the lithium-ion batteries must first be deactivated or discharged to make the remaining power of the lithium-ion batteries reach a safe and disassembled level. The discharge of waste lithium-ion batteries has important practical significance. The discharged batteries can suppress fire, explosion and environmental pollution, while insufficient discharge is prone to combustion during the battery recycling process, making it difficult to recover the valuable metals in the battery.

[0003] As a new "urban mine", waste lithium-ion batteries are in urgent need of disposal. They have the triple attributes of resources, environment and safety. Discharge is a key safety step in the battery processing process. The current great challenge is to develop a fast and low-cost discharge technology for waste lithium-ion batteries. As the amount of scrapped batteries increases further, ensuring the safe storage and handling of lithium batteries will inevitably become an important issue. The discharge or inactivation of waste lithium-ion batteries usually adopts methods such as conductors or semiconductors, low-temperature freezing and chemical solutions. Conductor or semiconductor discharge uses an external resistor / electronic load, and the voltage rises after discharge, leaving a huge safety hazard. The short-circuit discharge of metal powder or carbon material is unstable and prone to dust explosion. Liquid nitrogen cooling makes lithium ions inert. This method has high requirements for equipment and is not easy to operate in large quantities. Chemical solution discharge is to immerse the waste lithium-ion battery in a solution and short-circuit it to release the residual power. It is currently the safest and most reliable means. At present, most institutions use sodium chloride immersion to discharge waste lithium-ion batteries. This method is simple and easy to operate, and the discharge is thorough, but chloride ions and electrochemical corrosion cause electrolyte and valuable metals to leak. Sodium thiosulfate and zinc acetate have the characteristics of high dielectric cost and short discharge time. Discharge solutions such as carbonates have little corrosion to batteries and can effectively reduce organic and metal leakage, but the efficiency is low. Therefore, it is urgent to clarify the discharge path and explore a fast, clean and low-cost method for releasing residual electricity to achieve controllable discharge.

[0004] CN113871743A discloses a method for safe and fast discharge of waste lithium-ion batteries, which is to cover the waste lithium-ion batteries with copper powder conductive medium and then pour them into a discharge salt solution to perform physical discharge and chemical discharge at the same time. This method improves the discharge efficiency of waste lithium-ion batteries and can also prevent copper powder from oxidizing during the discharge process. The discharge salt solution is used to absorb a large amount of heat generated during the physical discharge process of the battery, avoid battery explosion and improve safety, and solve the disadvantage that the voltage is easy to rebound after the copper powder conductive medium is physically discharged; however, due to the use of external copper powder, it belongs to a kind of physical discharge, and the battery short-circuit effect is not good. This is because there is a large gap between the positive and negative electrode structures of the battery, and a good short circuit cannot be achieved by filling copper powder and aqueous solution, and the discharge current is intermittent.

[0005] CN116247322A discloses a method for discharging waste lithium-ion batteries, which comprises destroying the shape of the waste lithium-ion batteries in advance, discharging them in pure water or tap water for a period of time, taking them out, and drying the batteries by self-heating, thereby discharging the waste lithium-ion batteries, and the process is relatively simplified. However, this method increases the safety risk of discharge in the process of destroying the pretreatment of the batteries. At the same time, using pure water and tap water as the medium for discharge when the pretreatment is not done properly will increase the discharge time of the batteries, affect the discharge effect, and bring inconvenience to the subsequent drying by releasing heat from the batteries themselves.

[0006] CN106252772A discloses a method for rapid discharge of waste lithium-ion batteries, which involves soaking the lithium-ion batteries in salt water with a mass concentration of 3%-5% for 10-15 days to generate a large amount of hydrogen and oxygen, taking them out and drying them, and using a needle piercing machine to pierce the inside of them for half an hour before pulling them out, thereby achieving full discharge of the waste lithium-ion batteries, and having the characteristics of simple operation and obvious effect. However, during the salt water discharge process, the electrodes are severely corroded, a large amount of electrolyte leaks, causing difficulties in subsequent water treatment, and the organic gases generated also need to be collected and processed in a centralized manner, increasing costs.

[0007] It is generally believed that the electrolysis of water is the only path for the voltage of waste lithium-ion batteries to drop during solution discharge. However, a series of loaded redox competitive reactions may occur at the positive and negative electrodes of the battery in acidic and alkaline solutions. The battery potential of water electrolysis is -1.23V, which can be carried out through alkaline or acidic reaction pathways. Applying a voltage higher than -1.23V will cause water electrolysis. In addition to the water decomposition reaction, other anions or cations in the salt solution may also undergo redox on the electrode surface. Through monitoring and research on the discharge process, it was found that there are three ways for waste lithium-ion batteries to release electricity: electrolysis of water, electrolyte leakage, and battery short-circuit heat release. Among them, the solution discharge path represented by sodium chloride and potassium chloride is mainly electrolyte leakage, supplemented by electrolysis of water, with a high discharge rate, but causing a large amount of metal corrosion and electrolyte leakage. The solution discharge represented by tap water and pure water is mainly electrolysis of water, which will not cause a large amount of corrosion leakage, but the discharge rate is very low. This is mainly because the battery voltage drop caused by electrolyte leakage is much greater than the water electrolysis path. The same carbonate mainly uses the water electrolysis discharge path, which has the lowest efficiency. Summary of the invention

[0008] In view of the shortcomings of the existing discharge technology, such as slow speed, serious battery corrosion after discharge, and a large amount of discharge wastewater, the present invention uses a mixed sulfate or chloride solution as a discharge medium, immerses the waste lithium-ion battery in it, and realizes discharge by using the directional movement of electrons formed by the external short-circuit principle. Since the battery is in the discharge solution, it will not cause thermal runaway of the battery, there is no obvious corrosion of the battery after discharge, and there is basically no leakage of the electrolyte in the battery. Fully automated equipment is used to discharge it safely and efficiently, and the wastewater and waste gas generated during the discharge process are treated and disposed accordingly to achieve wastewater recycling. The present invention mainly relates to a method and supporting equipment for using sulfate or chloride solution as a medium to immerse waste lithium-ion batteries in a salt solution to enable rapid discharge. The equipment can effectively improve the discharge efficiency, reduce the metal loss of the battery, and reduce environmental pollution, and ensure the subsequent safe treatment and disposal of waste lithium-ion batteries.

[0009] In order to solve the above problems, the present invention provides a waste lithium ion battery fast discharge device and method. The method and device are waste lithium ion discharge agents and devices using sulfate or chloride solution as discharge medium, which mainly inhibit the electrolysis process of water, adjust the pH value and add metal cations, so that the metal ions in the solution are reduced by electrons at the negative electrode, and the precipitated metal elements are accumulated and crystallized between the positive and negative electrode grooves or the connection gaps to cause an external short circuit in the battery. The crystals are very firm and difficult to fall off, and the residual electricity is quickly released, thereby causing the battery to fail and the battery to be completely discharged.

[0010] The present invention adopts the following technical solutions:

[0011] A waste lithium-ion battery rapid discharge device, comprising a battery basket, a discharge battery, a discharge battery circulation pump, a discharge battery filter press, a cleaning tank, a cleaning tank circulation pump, a cleaning tank filter press, a chain plate unloader, a high-pressure air dryer, a wastewater treatment unit and a waste gas treatment unit;

[0012] The battery basket is used to hold lithium batteries. The discharged batteries are connected to the discharged battery circulation pump. The discharged battery filter press is connected to the discharged battery circulation pump through a pipeline. At the same time, the filtrate outlet of the discharged battery filter press is connected to the bottom of the discharged battery through a pipeline; the cleaning tank circulation pump is connected to the cleaning tank through a pipeline, and the cleaning tank filter press is connected to the cleaning tank circulation pump using a pipeline; a pipeline is connected between the discharged battery and the cleaning tank; a chain plate unloader is arranged at the tail of the cleaning tank, and a high-pressure air dryer is arranged on the chain plate unloader; the filtrate outlet of the cleaning tank filter press and the filtrate outlet of the discharged battery filter press are respectively connected to the wastewater treatment unit; the waste gas treatment unit is placed on the upper part of the discharged battery.

[0013] A method for rapidly discharging a waste lithium-ion battery, using the device as described above, the method comprising the following steps:

[0014] (1) Detect the voltage of used lithium batteries and determine the initial voltage;

[0015] (2) immersing the lithium battery in a discharge solution containing a discharge solution; preferably, the mass ratio of the lithium battery to the discharge solution is 1:1-1:2;

[0016] (3) After discharging for 1 to 20 hours, remove and clean the battery, and measure its voltage to ensure it is less than 0.5V and below the safe voltage. Regularly treat the discharge wastewater and recycle it.

[0017] Specifically, a method for rapid discharge of waste lithium batteries includes the following steps: the pH value of the sulfate or chloride mixed solution is in the range of 2.5-6.5, the mass concentration is 5%-30%, the discharge time is within 1-20 hours, the solid-liquid ratio of the discharge battery to the solution is in the range of 1:1 to 1:2 by mass ratio, the solution temperature is 10-40°C, and the discharge process is divided into two path stages, namely, slow electrolysis of water and rapid drop of short-circuit exothermic voltage. In the initial stage, the plateau pressure drop is small, mainly electrolysis of water; then the battery external short circuit occurs, the residual voltage drops drastically, and the electrolyte and metal are dissolved. The metal ions in the solution gain electrons and are reduced, and the precipitated metal accumulates and crystallizes between the positive and negative electrodes. The crystals are very firm and difficult to fall off, causing the battery to have an external short circuit, the residual electricity is quickly released, and the solution heats up. Since the selected metal ion solution is very easy to undergo a competitive reduction reaction to generate a metal element to cause the battery to short circuit, it is difficult for the water electrolysis reaction to produce gas.

[0018] The present invention adopts mixed sulfate or chloride as the discharge medium, which can not only reduce the corrosion of the electrode, but also ensure the efficient and stable discharge. The sulfate includes one or more of sodium sulfate, potassium sulfate, magnesium sulfate, aluminum sulfate, ferrous sulfate, ferric sulfate, copper sulfate, manganese sulfate, zinc sulfate, nickel sulfate, cobalt sulfate and ammonium sulfate; the chloride includes one or more of sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, ferric chloride, ferrous chloride, copper chloride, nickel chloride, cobalt chloride and zinc chloride.

[0019] Specifically, the invention discloses a waste lithium battery rapid discharge device, the device comprises a battery basket, a discharge battery, a discharge battery circulation pump, a discharge battery filter press, a cleaning tank, a cleaning tank circulation pump, a cleaning tank filter press pump, a chain plate unloader, a high-pressure air dryer, an oil separator, a regulating tank, a primary reaction tank, a wastewater treatment primary filter press, a secondary reaction tank, a wastewater treatment secondary filter press, a wastewater circulation pump, a secondary sedimentation tank, an AO tank, a sedimentation tank, an exhaust hood, a spray tower, an activated carbon adsorption box, and an exhaust gas induced draft fan. The battery basket is initially located on the ground, and its elevation, lowering, forward and backward movement are controlled by a crane in the factory. The liquid and gas phases of all the above equipment are connected through pipelines. A solid container is arranged under the four filter presses. The undischarged batteries enter the battery basket and are grabbed and fed by a manipulator. The discharged batteries are dumped from the battery basket into the chain plate unloader, and then packaged into a ton bag and transported to the uniform vibrating feeder in the battery crushing workshop.

[0020] Furthermore, in step (1), the initial voltage is 2.5V~4.2V.

[0021] Furthermore, in step (1), the lithium battery is one or more of waste ternary nickel-cobalt-manganese lithium ion batteries, waste lithium iron phosphate batteries and waste lithium cobalt oxide batteries.

[0022] Furthermore, in step (2), the discharge solution is a sulfate mixed solution or a chloride mixed solution; the mass concentration of the sulfate mixed solution is 5% to 30%. The mass concentration of the chloride mixed solution is 5% to 30%. For example, the mass concentration of the sulfate mixed solution is 5%, 7%, 10%, 15%, 20%, 25% or 30%. The mass concentration of the chloride mixed solution is 5%, 7%, 10%, 15%, 20%, 25% or 30%.

[0023] Furthermore, the sulfate mixed solution is (a) a mixed solution of sodium sulfate, copper sulfate, ferrous sulfate and zinc sulfate; (b) a mixed solution of potassium sulfate, ferrous sulfate and zinc sulfate; (c) one or more of aluminum sulfate, magnesium sulfate solution and copper sulfate mixed solution. Preferably, in (a) the mass ratio of sodium sulfate, copper sulfate, ferrous sulfate and zinc sulfate is 1:9:9:1; in (b) the mass ratio of potassium sulfate, ferrous sulfate and zinc sulfate is 1:7:2; in (c) the mass ratio of aluminum sulfate, magnesium sulfate solution and copper sulfate is 1:1:8.

[0024] Furthermore, the chloride salt mixed solution is one or more of (a1) a potassium chloride and cupric chloride mixed solution; (b1) a sodium chloride, ferrous chloride and cupric chloride mixed solution; (c1) a ferrous chloride, nickel chloride, cobalt chloride and ferric chloride mixed solution; (d1) a sodium chloride, zinc chloride and cupric chloride mixed solution; (e1) a ferrous chloride, cupric chloride and ferric chloride mixed solution. Preferably, in the mixed solution (a1), the mass ratio of potassium chloride to cupric chloride is 3:7; in the mixed solution (d1), the mass ratio of sodium chloride, zinc chloride and cupric chloride is 1:1:8; in the mixed solution (e1), the mass ratio of ferrous chloride, cupric chloride and ferric chloride is 2:1:7.

[0025] The working principle of the device is:

[0026] (1) Pre-discharged waste lithium-ion batteries are placed into battery baskets manually or by crane. The bottom and sides of the silo are perforated sieve plates. The materials can fully contact the liquid discharge fluid in the liquid discharge chamber, and the discharge fluid medium can flow freely in the discharge chamber.

[0027] (2) The battery basket is transferred to various parts of the main discharge equipment through the control of an external crane.

[0028] (3) During discharge, the battery basket containing unprocessed used lithium-ion batteries is transferred to the discharge battery.

[0029] (4) Allow the battery to discharge for 1-20 hours, and filter the impurities in the water through a filter press regularly. Then, filter the water through the filter press system for recycling.

[0030] (5) After the battery voltage drops below 0.5V, the battery basket is transferred to the clean water tank by a crane to clean the residual discharge medium on the battery. The solid residue in the discharged battery is quickly cleaned by the flow of clean water in and out, and the impurities in the water are filtered out by the filtration system while ensuring the fluidity of the cleaning liquid, and then the circulating water is recycled.

[0031] (6) After cleaning, the battery basket is transferred to the chain plate unloader by a crane, and then the positive pressure of the high-pressure air at the upper end of the high-pressure air dryer is used to blow away the moisture, dry the small amount of water in the battery, and blow away the residual water stains on its surface.

[0032] (7) Finally, the used lithium-ion batteries are transferred to ton bags and sent to the crushing pretreatment process for valuable metal separation.

[0033] (8) The wastewater can pass through the oil separator to remove some organic solvents, and then pass through the bottom to the equalization tank for uniform mixing; calcium hydroxide and calcium chloride need to be added to the primary reaction tank to remove impurities such as fluorine and phosphorus in the wastewater; after filtration in the plate and frame filter press, the filtrate enters the secondary reaction tank, which is acidified and activated carbon, PAC, PAM, etc. are added to effectively reduce the BOD and heavy metal impurity content in the wastewater. After filtration by the plate and frame filter press, it is precipitated for a period of time and sampled and analyzed. After meeting the standards, it can be pumped into the wastewater pipeline of the environmental protection department for treatment, or transferred to the AO tank for microbial oxidation and decomposition to further decompose the BOD in the wastewater, and then transferred to the secondary sedimentation tank and pumped into the discharge battery for recycling.

[0034] (9) During the discharge process, the exhaust hood, spray tower, activated carbon adsorption box, and induced draft fan work simultaneously to treat the waste gas generated and remove water and VOCs.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The method of the present invention uses less ester hydrolysis in sulfate or chloride solution, and has outstanding performance in preventing electrolyte dissolution. At the same time, metal loss is small, the water electrolysis stage of the discharge process is short, and a very small amount of hydrogen and oxygen is generated.

[0037] (2) The method of the present invention is convenient to operate and has high discharge efficiency by directly immersing the battery in a sulfate or chloride solution. The battery voltage can be reduced to ≤0.5V within 1-20 hours and the cost is relatively low.

[0038] (3) The equipment described in the present invention can discharge waste lithium-ion batteries in batches and has a high degree of automation, thereby improving discharge efficiency, reducing labor costs, and also reducing related safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Rapid discharge system for waste lithium batteries;

[0040] In the figure: 1-battery basket, 2-battery discharge, 3-battery discharge circulation pump, 4-battery discharge filter press, 5-cleaning tank, 6-cleaning tank circulation pump, 7-cleaning tank filter press, 8-chain plate unloader, 9-high pressure air dryer, 10-oil separator, 11-regulating tank, 12-primary reaction tank, 13-wastewater treatment primary filter press, 14-secondary reaction tank, 15-wastewater treatment secondary filter press, 16-wastewater circulation pump, 17-secondary sedimentation tank, 18-AO tank, 19-sedimentation tank, 20-exhaust hood, 21-spray tower, 22-activated carbon adsorption box, 23-exhaust gas induced draft fan;

[0041] Figure 2 This is a process flow chart for rapid discharge of waste lithium batteries;

[0042] Figure 3 The residual voltage of the battery of Comparative Example 1 varies with time;

[0043] Figure 4 This is a graph showing the variation of the residual voltage of the battery over time in Comparative Example 2;

[0044] Figure 5 This is a graph showing the variation of the residual voltage of the battery of comparative example 3 over time. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution: Figure 1 As shown, the present invention is a waste lithium-ion battery fast discharge device, including a battery basket 1, a discharge battery 2, a discharge battery circulation pump 3, a discharge battery filter press 4, a cleaning tank 5, a cleaning tank circulation pump 6, a cleaning tank filter press 7, a chain plate unloader 8, a high-pressure air dryer 9, a grease trap 10, a regulating tank 11, a primary reaction tank 12, a wastewater treatment primary filter press 13, a secondary reaction tank 14, a wastewater treatment secondary filter press 15, a wastewater circulation pump 16, a sedimentation tank 19, an AO tank 18, a secondary sedimentation tank 17, an exhaust hood 20, a spray tower 21, an activated carbon adsorption box 22 and an exhaust gas induced draft fan 23.

[0046] The waste lithium-ion battery rapid discharge equipment mainly includes a discharge battery 2, a battery basket 1, a cleaning tank 5, an exhaust gas treatment unit and a wastewater treatment unit. This equipment mainly controls the battery basket in the clean water tank, the cleaning tank and the unloading and drying unit through an external crane to discharge, clean residual solids and remove water stains on the battery surface. The unloading and drying unit includes a chain plate unloader 8 and a high-pressure air dryer 9.

[0047] A crane is installed in the factory building, which is mainly used to transfer battery baskets 1 and lithium batteries. Battery baskets 1 are on the ground for holding lithium batteries. Battery baskets 1 are welded from hollow 316L steel plates, and a latch quick-opening mechanism is provided at the bottom to facilitate the rapid unloading of batteries from the bottom. Battery discharge 2 is built with bricks and cement, and the surface is brushed with anti-corrosion clay. Battery discharge circulation pump 3 is connected to battery discharge 2 through UPVC pipes, and battery discharge filter press 4 is connected to battery discharge circulation pump 3 through UPVC pipes. At the same time, the filtrate outlet of battery discharge filter press 4 is connected to the bottom of battery discharge 2 through pipes. Cleaning tank 5 is also built with bricks and cement, and the surface is brushed with anti-corrosion clay. Cleaning tank circulation pump 6 is connected to cleaning tank 5 through UPVC pipes, and cleaning tank filter press 7 is also connected to cleaning tank circulation pump 6 through pipes. A UPVC pipe is connected between battery discharge 2 and cleaning tank 5 to facilitate the exchange of aqueous solutions on both sides. Chain plate unloader 8 is arranged at the tail of cleaning tank 5, and high-pressure air dryer 9 is provided on chain plate unloader 8. The filtrate outlet of the cleaning tank filter press 7 and the filtrate outlet of the discharge battery filter press 4 are respectively connected to the oil separator 10. The wastewater treatment unit includes a sequentially connected oil separator 10, a regulating tank 11, a primary reaction tank 12, a wastewater treatment primary filter press 13, a secondary reaction tank 14, a wastewater treatment secondary filter press 15, a sedimentation tank 19, an AO tank 18, a secondary sedimentation tank 17 and a wastewater circulation pump 16, and the above components are connected through UPVC pipes. The exhaust gas treatment unit includes an exhaust hood 20, a spray tower 21, an activated carbon adsorption box 22 and an exhaust gas induced draft fan 23, and the above components are connected and installed through 316L stainless steel pipes, wherein the exhaust hood 20 is arranged directly above the discharge battery.

[0048] All lithium batteries (the lithium batteries are one, two or three of cylindrical batteries, soft-pack batteries and square-shell batteries) are initially on the shelves or in ton bags, and the battery basket 1 is placed flat on the ground. After each discharge starts, the batteries on the shelves are placed in the battery basket 1 by a manipulator or the batteries in the ton bag are placed in the battery basket 1 by a crane, and the battery basket 1 is lifted and lowered and translated by an external crane installed in the factory.

[0049] like Figure 2 As shown, the operating steps of the waste lithium-ion battery rapid discharge device are as follows:

[0050] 1. First, place the waste cylindrical / soft pack / square power batteries manually or by using a robot into the battery basket 1. The bottom and sides of the basket are hollow steel plates to ensure that the materials can fully contact the discharge solution in the battery 2 and allow the discharge solution medium to flow freely in the discharge chamber.

[0051] 2. Use a crane to lift the battery basket 1 into the discharge battery 2 containing the aforementioned discharge solution, and discharge for 1-20 hours. Use an external meter to measure the battery voltage. When the voltage is ≤0.5V, the discharge is completed. Use a crane to transfer the battery basket 1 together with the discharged battery to the cleaning tank 5. Regularly filter the iron and aluminum impurities in the solution through the discharge battery circulation pump 3 and the discharge battery filter press 4, and recycle the aqueous solution. The waste gas generated in the discharge battery is successively treated by the exhaust hood 20, the spray tower 21, and the activated carbon adsorption box 22 to meet the standards, and then discharged into the atmosphere through the exhaust gas induced draft fan 23.

[0052] 3. The discharged battery basket 1 is hoisted into the cleaning tank 5. The solid residue contained in the discharged battery is quickly cleaned by the flow of clean water in and out. The impurities in the solution are filtered through the cleaning tank circulation pump 6 and the cleaning tank filter press 7. At the same time, the fluidity of the cleaning liquid is ensured, and the cleaning water is recycled.

[0053] 4. After cleaning, continue to use the crane to place the batteries in the battery basket 1 on the chain plate unloader 8, open the latch quick-opening mechanism at the bottom of the battery basket 1, and the cleaned batteries can be automatically unloaded at the front section of the chain plate, and a small amount of water will automatically flow out. During the forward movement of the chain plate unloader 8, the high-pressure air dryer 9 on the top starts to work to dry the soaked batteries, and the discharged batteries are packaged by adjusting the speed of the chain plate conveyor.

[0054] 5. Pack the batteries into ton bags and prepare to send them to the crushing pre-processing workshop.

[0055] 6. The battery discharge wastewater or cleaning pool wastewater can pass through the oil separator 10 to remove part of the organic solvent, and then pass through the bottom to the regulating tank 11 for uniform mixing; calcium hydroxide and calcium chloride need to be added to the primary reaction tank 12 to remove impurities such as fluorine and phosphorus in the wastewater; after filtering by the primary filter press 13 for wastewater treatment, the filtrate enters the secondary reaction tank 14, and is acidified in the reaction tank. The addition of activated carbon, PAC, PAM, etc. can effectively reduce the BOD and heavy metal impurity content in the wastewater. After filtering by the secondary filter press 15 for wastewater treatment, it is passed into the sedimentation tank 19 for sampling and analysis for a period of time. After meeting the standards, it can be pumped into the wastewater pipeline of the environmental protection department for treatment, or transferred to the AO tank 18 for microbial oxidation and decomposition to further decompose the BOD in the wastewater, and then transferred to the secondary sedimentation tank 17, and pumped into the battery discharge or cleaning pool through the wastewater circulation pump 16 for recycling.

[0056] Example 1

[0057] In this specific embodiment, sodium sulfate, copper sulfate, ferrous sulfate and zinc sulfate are mixed in a mass ratio of 1:9:9:1 to obtain a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 10%. The solid-liquid mass ratio of the waste ternary nickel-cobalt-manganese lithium-ion battery to the discharge solution is 1:1, and the reaction temperature is 20° C. The waste ternary nickel-cobalt-manganese lithium-ion battery is subjected to a discharge treatment. The specific operation steps are as follows:

[0058] (1) Test the voltage of the used lithium battery and determine that the initial voltage is 4.1V.

[0059] (2) Soak the used lithium batteries in a discharge solution to discharge them.

[0060] (3) After discharging for 9 hours, remove and clean the battery, and measure its voltage to be 0.26V<0.5V, which can reach the safety voltage. Regularly treat the discharge wastewater and recycle it.

[0061] Example 2

[0062] In this specific embodiment, potassium sulfate, ferrous sulfate and zinc sulfate are mixed in a mass ratio of 1:7:2 to obtain a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 15%. The solid-liquid mass ratio of the waste ternary nickel-cobalt-manganese lithium-ion battery to the discharge solution is 1:2, and the reaction temperature is 30° C. The waste ternary nickel-cobalt-manganese lithium-ion battery is subjected to a discharge treatment. The specific operation steps are as follows:

[0063] (1) Test the voltage of the used lithium battery and determine the initial voltage is 3.9V.

[0064] (2) Soak the lithium battery in a discharge solution.

[0065] (3) After discharging for 2.5 hours, remove and clean the battery, and measure its voltage to be 0.33V<0.5V, which is below the safe voltage. Regularly treat the discharge wastewater and recycle it.

[0066] Example 3

[0067] In this specific embodiment, aluminum sulfate, magnesium sulfate solution and copper sulfate are mixed in a mass ratio of 1:1:8 to obtain a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 10%. The solid-liquid mass ratio of the waste lithium cobalt oxide battery to the discharge solution is 1:2, the reaction temperature is 30°C, and the waste lithium cobalt oxide battery is discharged. The specific operation steps are as follows:

[0068] (1) Test the voltage of the used lithium battery and determine the initial voltage is 3.58V.

[0069] (2) Soak the lithium battery in a discharge solution.

[0070] (3) After discharging for 7.5 hours, remove and clean the battery, and measure its voltage to be 0.47V<0.5V, which is below the safe voltage. Regularly treat the discharge wastewater and recycle it.

[0071] Example 4

[0072] In this specific embodiment, potassium chloride and copper chloride are mixed in a mass ratio of 3:7 to obtain a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 25%. The solid-liquid mass ratio of waste lithium cobalt oxide to the discharge solution is 1:2, and the reaction temperature is 40°C. The waste lithium cobalt oxide battery is discharged. The specific operation steps are as follows:

[0073] (1) Test the voltage of the used lithium battery and determine the initial voltage is 3.75V.

[0074] (2) Soak the lithium battery in a discharge solution.

[0075] (3) After discharging for 2 hours, remove and clean the battery, and measure its voltage to be 0.12V<1.0V, which can reach the safety voltage. Regularly treat the discharge wastewater and recycle it.

[0076] Example 5

[0077] In this specific embodiment, sodium chloride, zinc chloride and copper chloride are mixed in a mass ratio of 1:1:8 to obtain a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 10%. The solid-liquid mass ratio of the waste lithium iron phosphate battery to the discharge solution is 1:2, and the reaction temperature is 40°C. The waste lithium iron phosphate battery is discharged. The specific operation steps are as follows:

[0078] (1) Test the voltage of the used lithium battery and determine that the initial voltage is 3.6V.

[0079] (2) Soak the lithium battery in a discharge solution.

[0080] (3) After discharging for 7 hours, remove and clean the battery, and measure its voltage to be 0.42V<0.5V, which is below the safe voltage. Regularly treat the discharge wastewater and recycle it.

[0081] Example 6

[0082] In this specific embodiment, ferrous chloride, cupric chloride and ferric chloride are mixed in a mass ratio of 2:1:7 to obtain a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 10%. The solid-liquid ratio of the waste lithium iron phosphate battery to the discharge solution is 1:2, and the reaction temperature is 40°C. The waste lithium iron phosphate battery is subjected to a discharge treatment. The specific operation steps are as follows:

[0083] (1) Test the voltage of the used lithium battery and determine the initial voltage is 4.2V.

[0084] (2) Soak the lithium battery in a discharge solution.

[0085] (3) After discharging for 1.5 hours, remove and clean the battery, and measure its voltage to be 0.18V<0.5V, which can reach the safety voltage. Regularly treat the discharge wastewater and recycle it.

[0086] Comparative Example 1:

[0087] In this specific embodiment, ammonium carbonate is used as a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 10%. The solid-liquid ratio of the waste ternary nickel-cobalt-manganese lithium battery to the discharge solution is 1:2, and the reaction temperature is 25° C. The waste ternary nickel-cobalt-manganese lithium battery is subjected to a discharge treatment. The specific operation steps are as follows:

[0088] (1) Test the voltage of the used lithium battery and determine the initial voltage is 3.7V.

[0089] (2) Soak the lithium battery in a discharge solution.

[0090] (3) After discharging for 1032 hours, the battery was taken out and cleaned, and its voltage was measured to be 1.23V>0.5V, which could not reach the safety voltage, and the discharge efficiency was very low. Figure 3 This is a graph showing the variation of the residual voltage of the battery in comparative example 1 over time.

[0091] Comparative Example 2:

[0092] In this specific embodiment, sodium sulfate is used as a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 20%. The solid-liquid ratio of the waste lithium iron phosphate battery to the discharge solution is 1:1, and the reaction temperature is 25°C. The waste lithium iron phosphate battery is discharged. The specific operation steps are as follows:

[0093] (1) Test the voltage of the used lithium battery and determine the initial voltage is 3.82V.

[0094] (2) Soak the lithium battery in a discharge solution.

[0095] (3) After discharging for 84.2 hours, the battery was removed and cleaned, and its voltage was measured to be 0.49V < 0.5V, which was below the safe voltage. However, the discharge efficiency was very low. Figure 4 This is a graph showing the variation of the residual voltage of the battery in comparative example 2 over time.

[0096] Comparative Example 3:

[0097] In this specific embodiment, sodium chloride is used as a discharge medium, and the discharge medium is dissolved in deionized water to obtain a discharge solution with a discharge medium mass concentration of 15%. The solid-liquid ratio of the waste ternary nickel-cobalt-manganese lithium battery to the discharge solution is 1:1.5, and the reaction temperature is 35° C. The waste ternary nickel-cobalt-manganese lithium battery is subjected to a discharge treatment. The specific operation steps are as follows:

[0098] (1) Test the voltage of the used lithium battery and determine the initial voltage is 3.66V.

[0099] (2) Soak the lithium battery in a discharge solution.

[0100] (3) After discharging for 70.5 hours, remove and clean the battery, and measure its voltage to be 0.48V < 0.5V, which is below the safe voltage. However, the discharge efficiency is very low. Figure 5 This is a graph showing the variation of the residual voltage of the battery of comparative example 3 over time.

Claims

1. A method for rapid discharge of waste lithium-ion batteries, characterized in that: The method uses a waste lithium-ion battery rapid discharge device, the discharge device comprising a battery basket (1), a discharge battery (2), a discharge battery circulation pump (3), a discharge battery filter press (4), a cleaning tank (5), a cleaning tank circulation pump (6), a cleaning tank filter press (7), a chain plate unloader (8), a high-pressure air dryer (9), a wastewater treatment unit and a waste gas treatment unit; The battery basket (1) is used to hold lithium batteries; the discharge battery (2) is connected to the discharge battery circulation pump (3); the discharge battery filter press (4) is connected to the discharge battery circulation pump (3) through a pipeline; and the filtrate outlet of the discharge battery filter press (4) is connected to the bottom of the discharge battery (2) through a pipeline; the cleaning pool circulation pump (6) is connected to the cleaning pool (5) through a pipeline; the cleaning pool filter press (7) is connected to the cleaning pool circulation pump (6) through a pipeline; a pipeline is connected between the discharge battery (2) and the cleaning pool (5); a chain plate unloader (8) is arranged at the rear of the cleaning pool (5), and a high-pressure air dryer (9) is arranged on the chain plate unloader (8); the filtrate outlet of the cleaning pool filter press (7) and the filtrate outlet of the discharge battery filter press (4) are respectively connected to the wastewater treatment unit; and the waste gas treatment unit is arranged on the upper part of the discharge battery (2); The method comprises the following steps: (1) Detect the voltage of used lithium batteries and determine the initial voltage; (2) Soak the lithium battery in a discharge solution containing a discharge solution; (3) After discharging for 1 to 20 hours, remove and clean the battery, and measure its voltage to ensure it is below 0.5V and safe voltage. Regularly treat the discharge wastewater and recycle it; In step (1), the initial voltage is 2.5V~4.2V; in step (2), the discharge solution is a chloride salt mixed solution; The chloride salt mixed solution is one or more of (a1) a mixed solution of potassium chloride and cupric chloride; (d1) a mixed solution of sodium chloride, zinc chloride and cupric chloride; (e1) a mixed solution of ferrous chloride, cupric chloride and ferric chloride; wherein, in the mixed solution (a1), the mass ratio of potassium chloride to cupric chloride is 3:7; in the mixed solution (d1), the mass ratio of sodium chloride, zinc chloride and cupric chloride is 1:1:8; in the mixed solution (e1), the mass ratio of ferrous chloride, cupric chloride and ferric chloride is 2:1:7; In step (2), the mass concentration of the chloride salt mixed solution is 5% to 25%.

2. The method according to claim 1, characterized in that The wastewater treatment unit comprises a grease trap (10), a regulating tank (11), a primary reaction tank (12), a primary wastewater treatment filter press (13), a secondary reaction tank (14), a secondary wastewater treatment filter press (15), a sedimentation tank (19), an AO tank (18), a secondary sedimentation tank (17) and a wastewater circulation pump (16) which are connected in sequence; the filtrate outlet of the cleaning tank filter press (7) and the filtrate outlet of the discharge tank filter press (4) are respectively connected to the grease trap (10).

3. The method according to claim 1, characterized in that The waste gas treatment unit comprises an exhaust hood (20), a spray tower (21), an activated carbon adsorption box (22) and a waste gas induced draft fan (23) which are connected in sequence; the exhaust hood (20) is placed on the upper part of the discharge cell (2).

4. The method according to claim 1, characterized in that: The lithium battery is one or more of a cylindrical battery, a soft-pack battery and a square-shell battery.

5. The method according to claim 1, characterized in that In step (1), the lithium battery is one or more of a waste ternary nickel-cobalt-manganese lithium battery, a waste lithium iron phosphate battery and a waste lithium cobalt oxide battery.

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