Retired lithium battery recovery system and recovery method based on intelligent regulation and control and multi-parameter safety interlocking

Abstract

The invention relates to a retired lithium battery recovery system and recovery method based on intelligent regulation and control and multi-parameter safety interlocking, and the retired lithium battery recovery system comprises an intelligent linkage electrified crushing unit, a low-temperature drying unit, a multi-stage sorting unit, a medium-temperature pyrolysis unit, a tail gas treatment unit and a cloud central control unit, the cloud central control unit is electrically connected with the intelligent linkage electrified crushing unit, the low-temperature drying unit, the medium-temperature pyrolysis unit and the tail gas treatment unit, so that the operation states of all the units are regulated and controlled. The recovery system provided by the invention can accurately regulate and control process parameters of each link, ensures efficient condensation and recovery of the electrolyte, avoids leakage of harmful substances and environmental pollution, also can realize accurate separation of materials, and greatly improves the resource recovery rate and the product purity.

Description

Technical Field

[0001] This invention relates to the field of waste lithium-ion battery recycling technology, specifically to a recycling system and method for retired lithium batteries based on intelligent control and multi-parameter safety interlocking. Background Technology

[0002] With the vigorous promotion of electric vehicles, the application of lithium batteries is becoming increasingly widespread, and a large number of power lithium batteries and lithium battery modules will face the problem of being scrapped in the future. If retired lithium batteries cannot be effectively recycled, it will not only cause waste of resources, but also pose serious safety hazards and environmental pollution risks: on the one hand, they are rich in high-value metals such as lithium, cobalt, and nickel, which are important strategic resources; on the other hand, the highly active substances (such as lithium-intercalated anodes and flammable electrolytes) and toxic components (such as lithium hexafluorophosphate and heavy metals) remaining inside the batteries can easily cause serious environmental safety problems such as combustion and explosion, heavy metal pollution, and fluoride leakage if not handled properly.

[0003] Currently, the recycling of retired lithium batteries generally includes steps such as discharging, dismantling, crushing, sorting, pyrolysis, metallurgy, refining, and waste disposal. Among these, the crushing step often employs a single-stage crushing method. Traditional single-stage crushing methods for processing retired lithium batteries do not strictly control the oxygen content, which is typically higher than 8%. In a high-oxygen environment, battery materials are highly susceptible to oxidation. To suppress this oxidation, large amounts of nitrogen are required for inert atmosphere protection, leading to high nitrogen consumption and significantly increased operating costs. Furthermore, the impacts and friction during crushing can easily activate internal chemical reactions within the battery, potentially causing electrolyte leakage and internal short circuits, leading to thermal runaway, fire, or even explosion. Especially when the residual battery voltage exceeds 2V, the safety risks increase significantly, posing a major safety hazard to operators and equipment.

[0004] In the pyrolysis step, the high-temperature decomposition of battery materials in the pyrolysis process often uses a fixed temperature. This not only makes it difficult to simultaneously meet the requirements for electrolyte evaporation and the decomposition of polyvinylidene fluoride (PVDF) binder, but also releases large amounts of toxic and harmful gases, such as hydrofluoric acid (HF) and various volatile organic compounds. These waste gases not only pollute the environment but also pose a threat to the health of operators. In addition, the battery powder obtained after pyrolysis has a high content of impurities such as copper and aluminum (exceeding 5%), which affects the purity and utilization value of subsequent material recycling and reduces resource recovery efficiency.

[0005] During the sorting of crushed materials, the process suffers from several drawbacks. Firstly, the sorting efficiency is low, and the product purity is insufficient. Incomplete sorting leads to severe cross-contamination between the separated products of the diaphragm, aluminum shell, and electrode materials. This not only affects the quality of the recovered materials but also increases the difficulty and cost of subsequent processing. Secondly, the sorting equipment has a complex structure and poor sealing, resulting in significant dust emission. Existing sorting equipment often consists of multiple redundant units, making the system complex and lacking sufficient sealing performance. This causes a large amount of dust to escape during the sorting process, polluting the environment and threatening the health of operators. Dust emission can also trigger equipment malfunctions and safety accidents, reducing the stability and reliability of the overall recycling system.

[0006] CN209472076U discloses a lithium-ion battery crushing and recycling device, but it cannot improve the sorting efficiency and product purity of the crushed material, and it does not treat the electrolyte, increasing the safety risks of subsequent processing. CN116273879A discloses a lithium battery crushing air separation system, which can effectively separate copper foil and aluminum foil from the lithium battery casing and separator, but the copper foil and aluminum foil are still mixed together after separation, and the lithium battery casing, separator, and plastic cannot be separated from each other, resulting in cross-contamination still existing.

[0007] Moreover, the existing process has the following problems: (1) the existing technology cannot achieve complete separation of electrolyte, and HF is easily generated during high-temperature pyrolysis (>500℃); (2) some methods use single-stage condensation recovery, which makes it difficult to effectively separate low-boiling-point impurities, resulting in the solvent not being directly reused; (3) the crushing process requires pre-discharging of the battery, which prolongs the processing flow, and its inert atmosphere control accuracy is insufficient (oxygen content is often higher than 8%), and mechanical impact during the crushing process can easily cause electrolyte leakage and thermal runaway; at the same time, there is a lack of real-time parameter control mechanism, and the response delay to abnormal conditions is large (>2s), which poses significant safety hazards; (4) The system has low integration. Each unit (crushing, pyrolysis, sorting, and exhaust gas treatment) operates independently and relies on manual adjustment of parameters. For example, the crushing speed and pyrolysis temperature need to be calibrated offline, resulting in large fluctuations in processing efficiency (±15%). Moreover, it cannot dynamically adapt the process according to the battery type (ternary / lithium iron phosphate) and aging degree, resulting in poor overall stability. (5) The safety interlock function is relatively simple, only monitoring conventional parameters such as temperature, flame, and oxygen content. It does not cover key risk factors such as crushing chamber pressure (which is prone to sudden increase due to dust accumulation) and sudden changes in VOCs concentration (signs of electrolyte leakage). It can only respond after the fact and cannot achieve early warning.

[0008] Therefore, how to achieve intelligent control of multiple parameters in the recycling process of retired lithium batteries and improve the safety, efficiency, environmental protection and economy of the recycling process is a technical problem that needs to be solved. Summary of the Invention

[0009] The purpose of this invention is to provide a retired lithium battery recycling system and method based on intelligent control and multi-parameter safety interlocking. Compared with the prior art, this invention can accurately control the process parameters of each link, ensure the efficient condensation and recovery of electrolyte, avoid leakage of harmful substances and environmental pollution, and also achieve precise separation of materials, greatly improving the resource recovery rate and product purity.

[0010] To achieve this objective, the present invention employs the following technical solution:

[0011] In a first aspect, the present invention provides a retired lithium battery recycling system based on intelligent control and multi-parameter safety interlocking, the retired lithium battery recycling system comprising:

[0012] Intelligent linkage live-line crushing unit, the intelligent linkage live-line crushing unit is used to crush live battery cells;

[0013] The low-temperature drying unit is connected to the solid phase outlet of the intelligent linkage electrified crushing unit, and the low-temperature drying unit is used to dry the crushed material.

[0014] A multi-stage sorting unit is provided, wherein the solid phase outlet of the low-temperature drying unit is connected to the multi-stage sorting unit, which is used to separate and recover various components including battery powder.

[0015] The battery powder outlet of the multi-stage sorting unit is connected to the medium-temperature pyrolysis unit, which is used for drying the electrolyte in the battery powder and pyrolysis of PVDF.

[0016] The exhaust gas treatment unit is connected to the exhaust gas outlets of the intelligent linkage electrified crushing unit, the low temperature drying unit, and the medium temperature pyrolysis unit, respectively, to ensure that the exhaust gas meets emission standards.

[0017] The cloud-based central control unit is electrically connected to the intelligent linkage electrified crushing unit, the low-temperature drying unit, the medium-temperature pyrolysis unit, and the exhaust gas treatment unit, respectively, to realize the regulation of the operating status of each unit.

[0018] The recycling system provided by this invention, through the coordinated operation of an intelligent linkage electric crushing unit, a low-temperature drying unit, a multi-stage sorting unit, a medium-temperature pyrolysis unit, a tail gas treatment unit, and a cloud-based central control unit, can precisely control the process parameters of each stage. This not only ensures the efficient condensation and recovery of the electrolyte but also avoids the leakage of harmful substances and environmental pollution. Furthermore, it enables precise separation of materials, significantly improving resource recovery rate and product purity while reducing energy consumption and waste gas emissions.

[0019] Preferably, the intelligent linkage electrified crushing unit includes a feeder and a crusher connected sequentially along the material movement direction.

[0020] Preferably, the crusher includes a dual-shaft sealed crusher, wherein the crushing chamber of the dual-shaft sealed crusher is equipped with a gas protection device to provide a protective atmosphere, and the gas protection device is electrically connected to the PLC control system of the crusher.

[0021] In this invention, the gas protection device can be, for example, a low-temperature nitrogen circulation system with a temperature range of -30°C to -15°C and a nitrogen purity of ≥99.99%, thereby suppressing battery activity without pre-discharge and significantly improving efficiency compared to traditional pre-discharge processes.

[0022] Preferably, the inlet and outlet of the crushing chamber are respectively equipped with double gate valves, and the double gate valves are electrically connected to the PLC control system of the crusher.

[0023] Preferably, a pressure relief valve is provided in the crushing chamber, and the pressure relief valve is electrically connected to the PLC control system of the crusher.

[0024] Preferably, a monitoring device is installed inside the crushing chamber to monitor temperature, oxygen content, and VOCs concentration. The monitoring device is electrically connected to the PLC control system of the crusher.

[0025] Preferably, the crushing chamber includes a coarse crushing chamber and a fine crushing chamber connected sequentially along the material movement direction, and is separated by a screen.

[0026] In this invention, by employing a twin-shaft sealed crusher and setting up a coarse crushing chamber and a fine crushing chamber, it is possible to achieve sequential coarse and fine crushing of materials.

[0027] Preferably, the crusher is further equipped with a flame detection device for monitoring and identifying flames, and the flame detection device is electrically connected to the crusher's PLC control system.

[0028] Preferably, the crusher further includes an emergency fire-fighting device, which is electrically connected to the crusher's PLC control system and is used by the PLC control system to activate the emergency fire-fighting water system.

[0029] Preferably, the exhaust outlet of the crusher is connected to the exhaust gas treatment unit.

[0030] Preferably, the low-temperature drying unit includes a low-temperature drying oven and a water-cooled screw conveyor arranged sequentially along the material movement direction.

[0031] Preferably, the interior of the low-temperature drying oven is equipped with spiral propulsion blades to propel the material within the oven.

[0032] In this invention, the furnace body of the low-temperature drying oven can adopt a fully sealed rotary structure, with internal spiral propulsion blades to achieve slow and uniform tumbling of materials in a low-oxygen and nitrogen environment, ensuring uniform heating. The furnace shell is externally insulated to reduce heat loss. The spiral propulsion blades can be made of wear-resistant and corrosion-resistant materials, suitable for long-term conveying of high-hardness powders.

[0033] In this invention, the water-cooled screw conveyor is equipped with a cooling water jacket on its exterior to provide cooling water circulation, reduce the discharge temperature to <70°C, quickly cool and dry the product, and prevent dust from reacting with air at high temperatures.

[0034] Preferably, the low-temperature drying oven is equipped with electric heating devices in sections, each comprising several independent heating sections, with the heating temperature of each section independently controlled to form a temperature gradient.

[0035] In this invention, the low-temperature drying oven is equipped with electric heating devices in different zones, which can control the temperature of each zone independently and form a temperature gradient to gradually vaporize the electrolyte, avoiding sudden heating that could cause the material to crack or gas to be released in a concentrated manner.

[0036] Preferably, a monitoring device is installed inside the low-temperature drying oven to monitor temperature and oxygen content, and the monitoring device is electrically connected to the PLC control system inside the low-temperature drying oven.

[0037] In this invention, the temperature of the low-temperature drying oven is generally controlled at 200℃-280℃. By controlling the temperature inside the low-temperature drying oven, the electrolyte can be fully volatilized without triggering PVDF pyrolysis, thereby achieving an electrolyte removal rate of ≥99%. At the same time, some low-boiling-point organic solvents are removed, reducing the release of harmful gases during subsequent pyrolysis and significantly reducing the risk of thermal runaway.

[0038] Preferably, a gas protection device is provided in the low-temperature drying oven to provide a protective atmosphere, and the gas protection device is electrically connected to the PLC control system in the low-temperature drying oven.

[0039] Preferably, the multi-stage sorting unit includes a dispersant and a linear screen arranged sequentially along the material movement direction. The undersize outlet of the linear screen is connected to a first battery powder collecting device, and the oversize outlet of the linear screen is connected to a first air separator.

[0040] In this invention, a dispersant is used to initially disperse the dried material. Through the vibration and collision of the dispersant, the solid particles in the material are evenly distributed, preventing particle agglomeration from affecting the subsequent sorting effect. The initial screening by a linear screen allows the refined positive and negative electrode powders to be sent as undersize material to the first battery powder collection device, while the electrode sheets, separators, aluminum shells, and copper-aluminum foil current collectors are sent as oversize material to the first air separator.

[0041] Preferably, the light material outlet of the first air separator is connected to the incinerator, and the heavy material outlet of the first air separator is connected to the second air separator via a first bucket elevator. In this invention, the function of the first air separator is to separate light materials (such as diaphragms) from heavy materials (such as electrode sheets, aluminum shells, and copper-aluminum foil current collectors). The light materials are sent to the incinerator for combustion, and the heavy materials are sent to the next step of separation.

[0042] Preferably, the heavy material outlet of the second air separator is connected in sequence to a grinder and a color sorter, and the light material outlet of the second air separator is connected in sequence to a hammer crusher and a circular vibrating screen via a second bucket elevator.

[0043] In this invention, the first bucket elevator or the second bucket elevator is equipped with a sealed dust cover.

[0044] In this invention, the second air separator separates heavy materials (such as aluminum shells and copper-aluminum foil current collectors) and light materials (electrode sheets). The heavy materials are ground and color sorted to obtain copper and aluminum materials. The light materials are crushed by a hammer crusher to remove the electrode powder from the current collector and then screened by a circular vibrating screen.

[0045] Preferably, the undersize outlet of the circular vibrating screen is connected to the second battery powder collecting device, and the oversize outlet of the circular vibrating screen is connected in sequence to the grinder and the color sorter.

[0046] In this invention, the undersize material obtained from the circular vibrating screen is battery powder, which is collected using a second battery powder collection device. The oversize material from the circular vibrating screen is a copper-aluminum mixture, which is ground and color sorted to obtain copper and aluminum materials, with impurity content of <10%. In this invention, the battery powder recovery rate is >90%, and the content of copper, aluminum, and other metallic impurities in the battery powder is <1%.

[0047] Preferably, the medium-temperature pyrolysis unit includes a medium-temperature rotary kiln and a cooling rotary kiln connected sequentially along the material movement direction.

[0048] In this invention, the temperature of the medium-temperature rotary kiln is controlled between 350℃ and 450℃. The kiln body is made of high-temperature resistant alloy steel and lined with a wear-resistant and corrosion-resistant coating, enabling it to withstand long-term pyrolysis conditions. The medium-temperature rotary kiln is equipped with lifting plates inside, which continuously tumble and drop the material within the kiln, thereby increasing the heating area and the uniformity of pyrolysis.

[0049] In this invention, the cooling rotary kiln is generally made of high-temperature resistant alloy steel and lined with a wear-resistant and corrosion-resistant coating to ensure long-term stable operation in harsh high-temperature working environments. Multiple spiral blades can be installed inside the cooling rotary kiln, which continuously agitate the pyrolysis products as the kiln rotates, ensuring uniform and efficient cooling of the material. The function of the cooling rotary kiln in this invention is to rapidly cool the high-temperature pyrolysis products discharged from the medium-temperature rotary kiln to below 70°C, preventing the powder or gas from re-contacting with air under high-temperature conditions and undergoing oxidation or secondary reactions, thus avoiding the release of harmful gases and substances.

[0050] Preferably, the medium-temperature rotary kiln includes several temperature zones, and the heating temperature of each temperature zone is independently controlled to form a temperature gradient.

[0051] In this invention, the medium-temperature rotary kiln is controlled to include several temperature zones. For example, the first temperature zone is controlled to be 350℃-380℃ and the second temperature zone is controlled to be 420℃-450℃. This ensures a smooth transition in the first temperature zone and ensures complete decomposition of PVDF in the second temperature zone, so that the pyrolysis rate of PVDF is ≥99%. This ensures that there is no residual binder on the surface of the positive and negative electrode powders, thereby improving the purity of the battery powder and the efficiency of subsequent smelting.

[0052] Preferably, a monitoring device is installed inside the medium-temperature rotary kiln. The monitoring device is used to monitor the oxygen content and temperature, and the monitoring device is electrically connected to the PLC control system of the medium-temperature rotary kiln.

[0053] In this invention, by monitoring the oxygen content in the medium-temperature rotary kiln, the supply of nitrogen can be fed back and controlled in real time, ensuring operation under a strict nitrogen atmosphere and preventing oxidation of metal powder and thermal runaway reaction.

[0054] Preferably, a gas protection device is installed inside the medium-temperature rotary kiln to provide a protective atmosphere, and the gas protection device is electrically connected to the PLC control system inside the medium-temperature rotary kiln.

[0055] Preferably, the exhaust gas outlet of the medium-temperature rotary kiln is connected to the exhaust gas treatment unit.

[0056] In this invention, PVDF is fully decomposed in a medium-temperature rotary kiln to produce fluorine-containing gas, which is then incinerated in the secondary combustion chamber of the tail gas treatment unit. Subsequently, a multi-stage alkaline spraying device is used for spray absorption to prevent harmful gases from escaping.

[0057] Preferably, a cooling water supply device is provided inside the cooling rotary kiln, and the cooling water supply device is electrically connected to the PLC control system of the cooling rotary kiln, and the PLC control system controls the flow rate of the cooling water.

[0058] In this invention, by setting up a cooling water supply device and intelligently controlling the flow rate of the cooling water, a good cooling rate can be achieved, avoiding cracks in the material due to excessively fast cooling or reaction residue caused by excessively slow cooling.

[0059] Preferably, a monitoring device is installed inside the cooling rotary kiln. The monitoring device is used to monitor the material temperature at the outlet of the cooling rotary kiln, and the monitoring device is electrically connected to the PLC control system of the cooling rotary kiln.

[0060] In this invention, by monitoring the temperature of the material at the outlet of the cooling rotary kiln in real time, it is possible to ensure that the temperature of the material after cooling is stable at <70℃. When the outlet temperature is too high, the PLC control system adjusts the cooling water supply device to increase the cooling water flow rate to ensure accurate temperature control.

[0061] Preferably, the exhaust gas treatment unit includes a condensation device, a secondary combustion chamber, a waste heat boiler, a quench tower, a dry reaction tower, a bag filter, and a multi-stage alkaline spraying device.

[0062] Preferably, a monitoring device is installed in the secondary combustion chamber to monitor temperature and oxygen content, and the monitoring device is electrically connected to the PLC control system of the secondary combustion chamber.

[0063] Preferably, a fuel nozzle is provided in the secondary combustion chamber, and the fuel nozzle is electrically connected to the PLC control system of the secondary combustion chamber.

[0064] Preferably, the exhaust gas outlet of the low-temperature drying unit is connected to a condenser.

[0065] In this invention, the condensation device may be, for example, a fully sealed rotary kiln with a negative pressure inside, specifically -0.08 MPa to -0.06 MPa, which can reduce HF generation.

[0066] Preferably, the non-condensable gas outlet and the condensate outlet of the condensation device are both connected to the secondary combustion chamber.

[0067] In this invention, the secondary combustion chamber can thoroughly destroy non-condensable materials, difficult-to-recover organic matter, electrolytes, and fluorine-containing harmful gases, thereby achieving harmless treatment of exhaust gas with an organic matter removal rate of ≥99.99%. For example, the organic matter is decomposed into CO2, H2O, etc., through incineration, followed by absorption treatment. In this invention, the secondary combustion chamber is a combustion-retention furnace lined with refractory materials and uses natural gas for assisted combustion, meeting the requirements of combustion at 1100℃-1170℃ with a gas residence time ≥2s.

[0068] Preferably, the exhaust gas outlets of the intelligent linkage electrified crushing unit and the medium-temperature pyrolysis unit are both connected to the secondary combustion chamber.

[0069] Preferably, the flue gas outlet of the secondary combustion chamber is connected to a waste heat boiler to generate steam or hot water.

[0070] In this invention, a waste heat boiler is used to recover heat energy from high-temperature flue gas to generate steam or hot water for process heating or plant utilization, thereby improving energy efficiency.

[0071] Preferably, the outlet of the waste heat boiler is connected to the quench tower.

[0072] In this invention, a quench tower is used to rapidly cool high-temperature flue gas, suppressing secondary products (such as certain secondary acidic gases or toxic intermediates), which is beneficial for subsequent absorption. The quench tower directly adopts a water spray design, rapidly reducing the flue gas temperature through atomized water spray.

[0073] Preferably, the outlet of the quench tower is connected to the dry reaction tower.

[0074] In this invention, the dry reaction tower employs dry adsorption to capture acidic gases (such as HF) in the remaining tail gas through solid-phase capture or chemical reaction neutralization, reducing the load on the subsequent multi-stage alkaline spraying device and minimizing the pollution of the washing liquid. For example, if dry slaked lime powder is used to react with HF gas to form stable salts, the exhaust gas from the dry reaction tower in this invention passes through a bag filter to capture dust.

[0075] Preferably, the outlet of the dry reaction tower is connected to a bag filter.

[0076] Preferably, the air outlet of the bag filter is connected to a multi-stage alkaline spraying device.

[0077] Preferably, the multi-stage alkaline spraying device includes a first alkaline spraying device and a second alkaline spraying device, wherein the air outlet of the first alkaline spraying device is connected to the second alkaline spraying device.

[0078] In this invention, a multi-stage alkaline spray device can further absorb and neutralize residual acidic gases (such as residual HF) in the exhaust gas. For example, using NaOH for absorption and neutralization can further remove soluble acidic gases, soluble organic matter, and absorbable particulate matter, thereby achieving emission standards.

[0079] In this invention, the multi-stage alkaline spraying device is a commonly used alkaline spraying device in the field of tail gas treatment processes. Each stage of the spraying device is equipped with an air inlet and an air outlet. The tail gas enters the device through the air inlet. The device is equipped with spray heads to spray the alkaline solution into small droplets. The spray liquid generally comes into countercurrent contact with the gas, and a physical absorption and neutralization reaction occurs. After the reaction, some pollutants in the tail gas are removed and then enter the next stage of alkaline spraying device or are discharged in compliance with standards. The waste liquid generated by spraying is collected and subsequently recycled or treated harmlessly.

[0080] Preferably, the signal input and signal output terminals of the cloud-based central control unit are independently electrically connected to the PLC control system of the crusher in the intelligent linkage electrified crushing unit, the PLC control system of the low-temperature drying furnace in the low-temperature drying unit, the PLC control system of the medium-temperature rotary kiln and the PLC control system of the cooling rotary kiln in the medium-temperature pyrolysis unit, and the PLC control system of the secondary combustion chamber in the exhaust gas treatment unit.

[0081] In this invention, the cloud-based central control unit stores a database of battery material characteristics, such as characteristic data of ternary batteries, lithium iron phosphate batteries, aluminum-cased batteries, soft-pack batteries, cylindrical batteries, or plastic batteries. The data is analyzed and processed using neural network algorithms, including but not limited to those used in the process. The system can determine alarms based on data provided by the monitoring device, match the optimal process parameters, and transmit the data to the PLC control system for regulation. Compared with existing processes, this can reduce downtime by 30%.

[0082] In a second aspect, the present invention provides a method for recycling retired lithium batteries based on intelligent regulation and multi-parameter safety interlocking, wherein the method for recycling retired lithium batteries adopts the retired lithium battery recycling system based on intelligent regulation and multi-parameter safety interlocking described in the first aspect of the present invention.

[0083] The method for recycling retired lithium batteries includes the following steps:

[0084] S1, crush the charged battery cells to obtain the crushed material;

[0085] S2, the crushed material is dried to obtain the dried material;

[0086] S3, the dried material is sorted in multiple stages to obtain various components including battery powder;

[0087] S4 involves pyrolyzing the battery powder, drying the electrolyte, and pyrolyzing the PVDF in the battery powder.

[0088] Among them, the exhaust gas generated from crushing, drying and pyrolysis is treated to meet emission standards.

[0089] Preferably, the recycling method further includes intelligent control, including: the monitoring devices installed in the crusher, low temperature drying furnace, medium temperature rotary kiln, cooling rotary kiln, and secondary combustion chamber respectively transmit the monitored parameter data to their respective PLC control systems via electrical signals;

[0090] The PLC control system uploads parameter data to the cloud-based central control unit via electrical signals. The cloud-based central control unit stores a database of battery material characteristics. Based on the real-time parameter data and the database, the cloud-based central control unit makes judgments, confirms abnormalities or alarms, obtains the optimal process parameters, and transmits the process parameters to the corresponding PLC control system in the form of electrical signals for regulation.

[0091] Preferably, the intelligent control in the crusher includes:

[0092] When the pressure inside the crushing chamber exceeds 0.12 MPa, the PLC control system uploads the pressure data to the cloud-based central control unit. The cloud-based central control unit determines that the safety threshold has been exceeded, triggers an audible and visual alarm, and sends a process signal to the crusher's PLC control system. This controls the pressure relief valve to open and the double gate valve at the crushing chamber inlet to reduce the feed, thereby reducing the crushing load by 30%-50%.

[0093] When the VOCs concentration in the crushing chamber exceeds 50ppm, the PLC control system uploads the VOCs concentration data to the cloud central control unit. The cloud central control unit determines that the safety threshold has been exceeded, issues a shutdown warning, and sends the process signal to the crusher's PLC control system, which controls the gas protection device to increase the nitrogen flow rate by 30%-50% and reduce the nitrogen temperature to -20℃ to -40℃.

[0094] In this invention, in order to prevent the VOCs concentration in the crushing chamber from being too high, the crushing speed can also be adjusted by the PLC control system. For example, when the VOCs concentration is >50ppm, the speed can be reduced by 20%.

[0095] When the oxygen content in the crushing chamber is greater than 5%, the PLC control system uploads the oxygen content data to the cloud central control unit. The cloud central control unit judges the abnormality and sends the process signal to the PLC control system of the crusher, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%.

[0096] When the temperature inside the crushing chamber exceeds 90℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends the process signal to the crusher's PLC control system, which then controls the gas protection device to increase the nitrogen flow rate by 10%-30%.

[0097] When the temperature inside the crushing chamber exceeds 120℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends the process signal to the crusher's PLC control system, which then controls the emergency fire-fighting device to activate the emergency fire-fighting water system.

[0098] When flames appear in the crushing chamber, the PLC control system uploads an electrical signal to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends a process signal to the crusher's PLC control system, which then controls the emergency fire-fighting device to activate the emergency fire-fighting water system.

[0099] In this invention, through the above-mentioned intelligent control of the crusher, risks can be predicted in advance, the abnormal response time is <0.5s, and the emergency response rate is ≥99%.

[0100] Preferably, the intelligent control in the low-temperature drying oven includes:

[0101] When the oxygen content in the furnace is greater than 5%, the PLC control system uploads the oxygen content data to the cloud central control unit. The cloud central control unit judges the abnormality and sends the process signal to the PLC control system of the low temperature drying oven, controlling the gas protection device to increase the nitrogen flow rate by 20%-40%.

[0102] In this invention, the PLC control system of the low-temperature drying oven can also control the feeding inside the oven at the same time. When the oxygen content is too high, such as >5%, the PLC control system can simultaneously control the feeding inside the oven to stop.

[0103] When the temperature inside the furnace exceeds 320℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends the process signal to the PLC control system of the low-temperature drying oven, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%.

[0104] In this invention, the PLC control system of the low-temperature drying oven can also control the operation and shutdown of the low-temperature drying oven at the same time. When the temperature is too high, such as >320℃, the PLC control system can control the low-temperature drying oven to shut down at the same time.

[0105] Preferably, the intelligent control in the medium-temperature rotary kiln includes:

[0106] When the oxygen content in the medium-temperature rotary kiln is greater than 4%, the PLC control system uploads the temperature data to the cloud central control unit. The cloud central control unit judges the abnormality and sends the process signal to the PLC control system of the medium-temperature rotary kiln, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%.

[0107] In this invention, the PLC control system of the medium-temperature rotary kiln can also simultaneously control the feeding and discharging of the medium-temperature rotary kiln. When the oxygen content in the kiln is too high, such as oxygen content > 4%, the feeding is stopped.

[0108] When the temperature inside the medium-temperature rotary kiln exceeds 510℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends the process signal to the PLC control system of the medium-temperature rotary kiln, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%.

[0109] In this invention, the PLC control system of the medium-temperature rotary kiln can also control the operation and shutdown of the medium-temperature rotary kiln simultaneously. When the temperature is too high, such as >510℃, the PLC control system can simultaneously control the shutdown of the medium-temperature rotary kiln.

[0110] Preferably, the intelligent control in the cooling rotary kiln includes:

[0111] When the material temperature at the outlet of the cooling rotary kiln exceeds 70°C, the temperature data is uploaded to the cloud-based central control unit by the PLC control system. The cloud-based central control unit detects the abnormality and sends the process signal to the PLC control system of the cooling rotary kiln, which then controls the cooling water supply device to increase the cooling water flow rate by 30%-50%.

[0112] Preferably, the intelligent control in the secondary combustion chamber includes:

[0113] When the temperature inside the secondary combustion chamber is less than 850℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit determines the abnormality and sends the process signal to the PLC control system of the secondary combustion chamber, controlling the fuel nozzle to increase the natural gas flow by 30%-100%.

[0114] In this invention, the secondary combustion chamber PLC control system can also promptly shut down the secondary combustion chamber and automatically cut off the entry of exhaust gas in case of a malfunction.

[0115] Compared with the prior art, the present invention has the following beneficial effects:

[0116] (1) The recycling system and recycling method provided by the present invention can accurately monitor the oxygen content, such as detecting the oxygen content in the crushing chamber. The nitrogen flow rate can be automatically adjusted through the PLC control system and the cloud central control unit to keep the oxygen content not exceeding 5%, effectively avoiding the occurrence of oxidation reaction and greatly reducing the danger in the battery crushing process.

[0117] (2) The recycling system and recycling method provided by the present invention can monitor the temperature in real time, such as the temperature in the crushing chamber, low temperature drying furnace or medium temperature rotary kiln, and can give timely warning of temperature abnormalities, prevent the spread of thermal runaway, and ensure stable operation of the equipment.

[0118] (3) The recycling system and recycling method provided by the present invention can detect flames in the crushing chamber in real time, identify and issue an alarm signal when the flame first appears, and activate emergency fire water to ensure that the flame is extinguished in time.

[0119] (4) By setting up an emergency fire-fighting device, the emergency fire-fighting water spray can be activated quickly to cool down and extinguish the fire source, preventing the fire from spreading.

[0120] (5) In this invention, by setting a pressure relief valve, it can be opened by intelligent control when the pressure in the crushing chamber is abnormally increased, so as to release excess gas and prevent the equipment from exploding or causing safety accidents due to excessive pressure.

[0121] (6) In this invention, a low-temperature nitrogen environment is provided by setting a gas protection device, so that the battery activity can be suppressed without pre-discharge. Compared with the traditional process, the processing time of a single batch of battery cells is shortened by 2 hours, and the nitrogen consumption is reduced by 40% compared with the traditional process.

[0122] (7) By setting up a cloud-based central control unit, the reaction time of the recycling system to emergencies can be shortened, the processing efficiency fluctuation can be ≤5%, the abnormal response time can be <0.5s, and the emergency response rate can be ≥99%. Furthermore, it can achieve early warning and multi-parameter interlocking intelligent control, reduce downtime by 30%, and reduce the equipment damage rate.

[0123] (8) By setting up a low-temperature drying unit and a medium-temperature pyrolysis unit, the low-temperature drying unit can achieve efficient volatilization and recovery of electrolyte, avoiding the violent release of harmful gases at high temperatures. The medium-temperature pyrolysis unit can accurately decompose PVDF binder, ensuring the purity and performance of the subsequently recycled materials, and significantly improving the safety and environmental friendliness of the pyrolysis process.

[0124] (9) This invention integrates multiple methods such as color sorting, gravity separation, and airflow sorting through a multi-stage sorting unit to efficiently separate aluminum, copper and other impurities in battery powder, control the content of copper and aluminum impurities in battery powder to below 1%, which is far below the industry standard of below 3%, and the separation efficiency between the separator and the aluminum shell exceeds 95%. The electrolyte recovery rate can reach up to 99% through the condensation device, effectively avoiding cross-contamination of materials and ensuring the purity and quality stability of the recovered materials.

[0125] (10) In this invention, by setting up an exhaust gas treatment unit and integrating multiple methods such as condensation, incineration, waste heat utilization, rapid cooling, dry absorption, bag filter dust collection and wet absorption, the final emission dust concentration can be reduced to less than 50 mg / Nm³. 3 It is far below the national standard of 100 mg / Nm 3 HF concentration controlled at 1 mg / Nm 3 Below that, far below 5 mg / Nm 3 In addition to meeting national emission standards, it has also effectively improved energy utilization and reduced overall energy consumption. Attached Figure Description

[0126] Figure 1 This is a flowchart of the recycling method provided in Embodiment 1 of the present invention. Detailed Implementation

[0127] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0128] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0129] Example 1

[0130] This embodiment provides a retired lithium battery recycling system based on intelligent control and multi-parameter safety interlocking. The retired lithium battery recycling system includes:

[0131] The system comprises the following components: an intelligent linkage charged crushing unit for crushing charged battery cells; a low-temperature drying unit, whose solid phase outlet is connected to the intelligent linkage charged crushing unit for drying the crushed material; a multi-stage sorting unit, whose solid phase outlet is connected to the low-temperature drying unit for separating and recovering various components, including battery powder; a medium-temperature pyrolysis unit, whose battery powder outlet is connected to the multi-stage sorting unit for drying the electrolyte and pyrolyzing PVDF in the battery powder; a tail gas treatment unit, whose tail gas outlets are connected to the intelligent linkage charged crushing unit, low-temperature drying unit, and medium-temperature pyrolysis unit to ensure that the tail gas meets emission standards; and a cloud-based central control unit, which is electrically connected to the intelligent linkage charged crushing unit, low-temperature drying unit, medium-temperature pyrolysis unit, and tail gas treatment unit to regulate the operating status of each unit.

[0132] The intelligent linkage electrified crushing unit includes a feeder and a crusher connected sequentially along the material movement direction. The crusher includes a dual-shaft sealed crusher. The crushing chamber of the dual-shaft sealed crusher is equipped with a gas protection device to provide a protective atmosphere. This gas protection device is electrically connected to the crusher's PLC control system. The inlet and outlet of the crushing chamber are respectively equipped with double gate valves, which are also electrically connected to the crusher's PLC control system. A pressure relief valve is installed inside the crushing chamber, and it is also electrically connected to the crusher's PLC control system. A monitoring device is installed inside the crushing chamber for... The crusher monitors temperature, oxygen content, and VOC concentration. The monitoring device is electrically connected to the crusher's PLC control system. The crushing chamber includes a coarse crushing chamber and a fine crushing chamber connected sequentially along the material movement direction and separated by a screen. The crusher is also equipped with a flame detection device to monitor and identify flames. This flame detection device is electrically connected to the crusher's PLC control system. The crusher also includes an emergency fire-fighting device, which is electrically connected to the crusher's PLC control system for activating emergency fire-fighting water. The crusher's exhaust gas outlet is connected to an exhaust gas treatment unit.

[0133] The low-temperature drying unit includes a low-temperature drying furnace and a water-cooled screw conveyor arranged sequentially along the material movement direction. The furnace body of the low-temperature drying furnace is equipped with screw propulsion blades to propel the material within the furnace body. The low-temperature drying furnace is divided into several sections with electric heating devices, each comprising several independent heating sections, the heating temperature of which is independently controlled to form a temperature gradient. A monitoring device is installed inside the low-temperature drying furnace to monitor temperature and oxygen content. The monitoring device is electrically connected to the PLC control system inside the low-temperature drying furnace. A gas protection device is installed inside the low-temperature drying furnace to provide a protective atmosphere. The gas protection device is also electrically connected to the PLC control system inside the low-temperature drying furnace.

[0134] The multi-stage sorting unit includes a dispersant and a linear screen arranged sequentially along the material movement direction. The undersize outlet of the linear screen is connected to a first battery powder collecting device, and the oversize outlet of the linear screen is connected to a first air separator. The light material outlet of the first air separator is connected to an incinerator, and the heavy material outlet of the first air separator is connected to a second air separator via a first bucket elevator. The heavy material outlet of the second air separator is sequentially connected to a grinder and a color sorter. The light material outlet of the second air separator is sequentially connected to a hammer crusher and a circular vibrating screen via a second bucket elevator. The undersize outlet of the circular vibrating screen is connected to a second battery powder collecting device, and the oversize outlet of the circular vibrating screen is sequentially connected to a grinder and a color sorter.

[0135] The intermediate-temperature pyrolysis unit includes an intermediate-temperature rotary kiln and a cooling rotary kiln connected sequentially along the material movement direction. The intermediate-temperature rotary kiln contains several temperature zones, each with independently controlled heating temperatures, forming a temperature gradient. A monitoring device is installed within the intermediate-temperature rotary kiln to monitor oxygen content and temperature; this device is electrically connected to the PLC control system of the intermediate-temperature rotary kiln. A gas protection device is installed within the intermediate-temperature rotary kiln to provide a protective atmosphere; this device is also electrically connected to the PLC control system within the intermediate-temperature rotary kiln. The tail gas outlet of the intermediate-temperature rotary kiln is connected to a tail gas treatment unit. A cooling water supply device is installed within the cooling rotary kiln; this device is electrically connected to the PLC control system of the cooling rotary kiln, which controls the flow rate of the cooling water. A monitoring device is installed within the cooling rotary kiln to monitor the material temperature at the outlet of the cooling rotary kiln; this device is also electrically connected to the PLC control system of the cooling rotary kiln.

[0136] The exhaust gas treatment unit includes a condensation device, a secondary combustion chamber, a waste heat boiler, a quench tower, a dry reaction tower, a bag filter, and a multi-stage alkaline spraying device. A monitoring device is installed in the secondary combustion chamber to monitor temperature and oxygen content. This monitoring device is electrically connected to the PLC control system of the secondary combustion chamber. Fuel nozzles are installed in the secondary combustion chamber and are also electrically connected to its PLC control system. The exhaust gas outlet of the low-temperature drying unit is connected to the condensation device. Both the non-condensable gas outlet and the condensate outlet of the condensation device are connected to the secondary combustion chamber. The intelligent linkage... The exhaust gas outlets of the electrified crushing unit and the medium-temperature pyrolysis unit are both connected to the secondary combustion chamber. The flue gas outlet of the secondary combustion chamber is connected to the waste heat boiler for generating steam or hot water. The exhaust port of the waste heat boiler is connected to the quench tower. The exhaust port of the quench tower is connected to the dry reaction tower. The exhaust port of the dry reaction tower is connected to the bag filter. The exhaust port of the bag filter is connected to a multi-stage alkaline spraying device. The multi-stage alkaline spraying device includes a first alkaline spraying device and a second alkaline spraying device. The exhaust port of the first alkaline spraying device is connected to the second alkaline spraying device.

[0137] The signal input and signal output terminals of the cloud-based central control unit are independently connected to the PLC control system of the crusher in the intelligent linkage electrified crushing unit, the PLC control system of the low-temperature drying furnace in the low-temperature drying unit, the PLC control system of the medium-temperature rotary kiln and the PLC control system of the cooling rotary kiln in the medium-temperature pyrolysis unit, and the PLC control system of the secondary combustion chamber in the exhaust gas treatment unit.

[0138] This embodiment also provides a method for recycling retired lithium batteries based on intelligent control and multi-parameter safety interlocking. The method utilizes the aforementioned retired lithium battery recycling system, taking a 24,000 t / year waste lithium iron phosphate battery processing line as an example. Figure 1 As shown, the method includes the following steps:

[0139] S1, crushing the charged battery cells to obtain the crushed material, specifically including:

[0140] The charged waste lithium iron phosphate batteries are fed into the twin-shaft sealed crusher via a feeding machine (belt conveyor). The crusher performs coarse and fine crushing sequentially. The crushing chamber is sealed with nitrogen by a gas protection device. Temperature, oxygen content, and VOCs concentration are monitored by a monitoring device, and the following intelligent controls are implemented: When the pressure in the crushing chamber > 0.12 MPa, the PLC control system uploads the pressure data to the cloud-based central control unit. The cloud-based central control unit determines that the pressure exceeds the safety threshold, triggers an audible and visual alarm, and sends a process signal to the crusher's PLC control system to open the pressure relief valve and control the double gate valve at the crushing chamber inlet to reduce the feed, thus reducing the crushing load by 30%-50%. When the VOCs concentration in the crushing chamber > 50 ppm, the PLC control system uploads the VOCs concentration data to the cloud-based central control unit. The cloud-based central control unit determines that the VOCs concentration exceeds the safety threshold, triggers a shutdown warning, and sends a process signal to the crusher's PLC control system to control the gas protection device to increase the nitrogen flow rate by 30%-50% and lower the nitrogen temperature to -20℃ to -40℃. When the oxygen content in the crushing chamber exceeds 5%, the PLC control system uploads the oxygen content data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the crusher's PLC control system, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%. When the temperature in the crushing chamber exceeds 90℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the crusher's PLC control system, controlling the gas protection device to increase the nitrogen flow rate by 10%-30%. When the temperature in the crushing chamber exceeds 120℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the crusher's PLC control system, controlling the emergency fire suppression device to activate the emergency fire suppression system. When flames appear in the crushing chamber, the PLC control system uploads an electrical signal to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the crusher's PLC control system, controlling the emergency fire suppression device to activate the emergency fire suppression system.

[0141] Through the above intelligent control, the oxygen content in the crushing chamber can be controlled at 3.5%±0.3%, ensuring that the crushing process is in a low-oxygen inert environment, avoiding the risk of oxidation and combustion. The particle size of the crushed material is controlled at 10mm-30mm so that the subsequent pyrolysis treatment is heated evenly.

[0142] S2, drying the crushed material to obtain the dried material, specifically including:

[0143] The crushed material is fed into a low-temperature drying oven, where the following intelligent controls are implemented: When the oxygen content inside the oven exceeds 5%, the PLC control system uploads the oxygen content data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the PLC control system of the low-temperature drying oven, controlling the gas protection device to increase the nitrogen flow rate by 20%-40%. When the temperature inside the oven exceeds 320℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the PLC control system of the low-temperature drying oven, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%.

[0144] Through the above intelligent regulation, the furnace temperature is stabilized at 250℃±5℃, and the residence time is about 1 hour. The organic solvent-based electrolyte (such as DMC and EC) is evaporated and condensed by the condenser in the tail gas treatment unit, achieving an electrolyte recovery rate of ≥99% and preventing the large-scale generation of harmful gases such as HF at high temperatures.

[0145] S3 involves multi-stage sorting of the dried material to obtain various components, including battery powder, specifically:

[0146] The dried material is dispersed by a dispersant and then screened through a 60-mesh linear sieve. The undersize material, battery powder 1, is sent to the first battery powder collection device, while the oversize material enters the first air separator. The first air separator separates the material into first light material and first heavy material. The first light material, mainly diaphragm material, is sent to an incinerator for combustion. The separation rate of the diaphragm material reaches 97%. The first heavy material (such as electrode sheets, aluminum casings, and copper-aluminum foil current collectors) is sent to the second separator for second air separation to obtain second light material and second heavy material. The second light material (such as electrode sheets) is hammer-crushed and then screened through a circular vibrating screen. The undersize material, battery powder 2, is collected by the second battery powder collection device, while the oversize material is a copper-aluminum mixture. The second heavy material (such as aluminum casings and copper-aluminum foil current collectors) and the copper-aluminum mixture are ground to make the metal particles finer and the surface smoother. Color sorting is then used to accurately identify the color of the metal, achieving efficient separation and recovery of copper and aluminum materials with a separation purity of ≥98%.

[0147] S4 involves pyrolyzing the battery powder, drying the electrolyte, and pyrolyzing the PVDF in the battery powder. Specifically, this includes:

[0148] Battery powder 1 and battery powder 2 are fed into a medium-temperature rotary kiln for pyrolysis. The first temperature zone is controlled at 350℃-380℃ and the second temperature zone at 420℃-450℃, ensuring a smooth transition in the first temperature zone and ensuring complete decomposition of PVDF in the second temperature zone. Intelligent regulation is implemented: when the oxygen content in the medium-temperature rotary kiln is >4%, the PLC control system uploads the temperature data to the cloud central control unit. The cloud central control unit detects the abnormality and sends a process signal to the PLC control system of the medium-temperature rotary kiln, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%; when the temperature in the medium-temperature rotary kiln is >510℃, the PLC control system uploads the temperature data to the cloud central control unit. The cloud central control unit detects the abnormality and sends a process signal to the PLC control system of the medium-temperature rotary kiln, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%.

[0149] Through the above intelligent regulation, the pyrolysis rate of PVDF is ≥99%, ensuring no residual binder and electrolyte residue <0.1%.

[0150] The pyrolyzed material discharged from the medium-temperature rotary kiln is cooled and discharged through a cooling rotary kiln. The cooling rotary kiln is equipped with a cooling water supply device and intelligently controls the flow rate of the cooling water. The intelligent control includes: when the material temperature at the outlet of the cooling rotary kiln is >70℃, the temperature data is uploaded to the cloud central control unit according to the PLC control system. The cloud central control unit judges the abnormality and sends the process signal to the PLC control system of the cooling rotary kiln, controlling the cooling water supply device to increase the cooling water flow rate by 30%-50%.

[0151] Through the above-mentioned intelligent control, by monitoring the temperature of the material at the outlet of the cooling rotary kiln in real time, it can be ensured that the temperature of the material after cooling is stable at <70℃. When the outlet temperature is too high, the PLC control system adjusts the cooling water supply device to increase the cooling water flow rate to ensure accurate temperature control.

[0152] S5, exhaust gas treatment, involves treating the exhaust gases generated from crushing, drying, and pyrolysis to ensure they meet emission standards. Specifically, this includes:

[0153] The exhaust gas from crushing and pyrolysis, and the electrolyte from condensation, enter the secondary combustion chamber for combustion. The combustion temperature is stabilized at 1150℃, and sufficient residence time is maintained. The intelligent control in the secondary combustion chamber includes: when the temperature in the secondary combustion chamber is <850℃, the PLC control system uploads the temperature data to the cloud central control unit. The cloud central control unit judges the abnormality and sends the process signal to the PLC control system of the secondary combustion chamber, controlling the fuel nozzle to increase the natural gas flow by 30%-100% to ensure the complete combustion and decomposition of harmful gases. The flue gas from the secondary combustion chamber enters the waste heat boiler for waste heat recovery, which recovers the heat energy from the high-temperature flue gas to generate steam or hot water for process heating or plant utilization. After heat recovery, the tail gas is rapidly cooled to 220°C through a quench tower to ensure that no harmful substances such as dioxins are produced in the tail gas. The tail gas is then passed into a dry reaction tower for dry absorption, where dry lime powder is used to react with acidic gases such as HF to generate stable salts. The mixture is then filtered by a bag filter. The tail gas is then sequentially passed through a first alkaline spray device and a second alkaline spray device for multi-stage spray absorption. The pH value of the spray solution is controlled at 11 to remove acidic gases such as HF through alkaline absorption.

[0154] The recycling system and method provided in this embodiment can achieve a battery powder recovery rate of ≥92%, with copper and aluminum impurities in the battery powder containing <0.8%, far below industry standards. The resulting copper and aluminum materials have a separation purity of ≥98%, making them suitable for direct use as smelting raw materials. Exhaust gas emissions comply with GB16297-1996 "Integrated Emission Standard for Air Pollutants," and HF concentration is controlled at <1 mg / Nm³. 3 Dust concentration below 50 mg / Nm 3 It meets national environmental protection requirements.

[0155] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A retired lithium battery recycling system based on intelligent control and multi-parameter safety interlocking, characterized in that, The retired lithium battery recycling system includes: Intelligent linkage live-line crushing unit, the intelligent linkage live-line crushing unit is used to crush live battery cells; The low-temperature drying unit is connected to the solid phase outlet of the intelligent linkage electrified crushing unit, and the low-temperature drying unit is used to dry the crushed material. A multi-stage sorting unit is provided, wherein the solid phase outlet of the low-temperature drying unit is connected to the multi-stage sorting unit, which is used to separate and recover various components including battery powder. The battery powder outlet of the multi-stage sorting unit is connected to the medium-temperature pyrolysis unit, which is used for drying the electrolyte in the battery powder and pyrolysis of PVDF. The exhaust gas treatment unit is connected to the exhaust gas outlets of the intelligent linkage electrified crushing unit, the low temperature drying unit, and the medium temperature pyrolysis unit, respectively, to ensure that the exhaust gas meets emission standards. The cloud-based central control unit is electrically connected to the intelligent linkage electrified crushing unit, the low-temperature drying unit, the medium-temperature pyrolysis unit, and the exhaust gas treatment unit, respectively, to realize the regulation of the operating status of each unit.

2. The decommissioned lithium battery recycling system according to claim 1, characterized in that, The intelligent linkage electrified crushing unit includes a feeder and a crusher connected sequentially along the material movement direction; Preferably, the crusher includes a twin-shaft sealed crusher, wherein the crushing chamber of the twin-shaft sealed crusher is equipped with a gas protection device to provide a protective atmosphere, and the gas protection device is electrically connected to the PLC control system of the crusher; Preferably, the inlet and outlet of the crushing chamber are respectively equipped with double gate valves, and the double gate valves are electrically connected to the PLC control system of the crusher; Preferably, a pressure relief valve is installed in the crushing chamber, and the pressure relief valve is electrically connected to the PLC control system of the crusher; Preferably, a monitoring device is installed inside the crushing chamber. The monitoring device is used to monitor temperature, oxygen content and VOCs concentration, and the monitoring device is electrically connected to the PLC control system of the crusher. Preferably, the crushing chamber includes a coarse crushing chamber and a fine crushing chamber connected sequentially along the material movement direction, and separated by a screen. Preferably, the crusher is further equipped with a flame detection device for monitoring and identifying flames, and the flame detection device is electrically connected to the crusher's PLC control system; Preferably, the crusher further includes an emergency fire-fighting device, which is electrically connected to the crusher's PLC control system and is used by the PLC control system to activate the emergency fire-fighting water system.

3. The decommissioned lithium battery recycling system according to claim 1 or 2, characterized in that, The low-temperature drying unit includes a low-temperature drying oven and a water-cooled screw conveyor arranged sequentially along the material movement direction. Preferably, the interior of the low-temperature drying oven is equipped with spiral propulsion blades to propel the material within the oven. Preferably, the low-temperature drying oven is equipped with electric heating devices in sections, each comprising several independent heating sections, the heating temperature of which is independently controlled to form a temperature gradient; Preferably, a monitoring device is installed inside the low-temperature drying oven to monitor temperature and oxygen content, and the monitoring device is electrically connected to the PLC control system inside the low-temperature drying oven. Preferably, a gas protection device is provided in the low-temperature drying oven to provide a protective atmosphere, and the gas protection device is electrically connected to the PLC control system in the low-temperature drying oven.

4. The decommissioned lithium battery recycling system according to any one of claims 1-3, characterized in that, The multi-stage sorting unit includes a dispersant and a linear screen arranged sequentially along the material movement direction. The undersize outlet of the linear screen is connected to the first battery powder collection device, and the oversize outlet of the linear screen is connected to the first air separator. Preferably, the light material outlet of the first air separator is connected to the incinerator, and the heavy material outlet of the first air separator is connected to the second air separator via a first bucket elevator; Preferably, the heavy material outlet of the second air separator is connected in sequence to a grinder and a color sorter, and the light material outlet of the second air separator is connected in sequence to a hammer crusher and a circular vibrating screen via a second bucket elevator. Preferably, the undersize outlet of the circular vibrating screen is connected to the second battery powder collecting device, and the oversize outlet of the circular vibrating screen is connected in sequence to the grinder and the color sorter.

5. The decommissioned lithium battery recycling system according to any one of claims 1-4, characterized in that, The medium-temperature pyrolysis unit includes a medium-temperature rotary kiln and a cooling rotary kiln connected sequentially along the material movement direction. Preferably, the medium-temperature rotary kiln includes several temperature zones, and the heating temperature of each temperature zone is independently controlled to form a temperature gradient; Preferably, a monitoring device is installed inside the medium-temperature rotary kiln. The monitoring device is used to monitor the oxygen content and temperature, and the monitoring device is electrically connected to the PLC control system of the medium-temperature rotary kiln. Preferably, a gas protection device is installed inside the medium-temperature rotary kiln to provide a protective atmosphere, and the gas protection device is electrically connected to the PLC control system inside the medium-temperature rotary kiln. Preferably, a cooling water supply device is provided inside the cooling rotary kiln, and the cooling water supply device is electrically connected to the PLC control system of the cooling rotary kiln, and the PLC control system controls the flow rate of the cooling water; Preferably, a monitoring device is installed inside the cooling rotary kiln. The monitoring device is used to monitor the material temperature at the outlet of the cooling rotary kiln, and the monitoring device is electrically connected to the PLC control system of the cooling rotary kiln.

6. The decommissioned lithium battery recycling system according to any one of claims 1-5, characterized in that, The exhaust gas treatment unit includes a condensation device, a secondary combustion chamber, a waste heat boiler, a quench tower, a dry reaction tower, a bag filter, and a multi-stage alkaline spraying device. Preferably, a monitoring device is installed in the secondary combustion chamber to monitor temperature and oxygen content, and the monitoring device is electrically connected to the PLC control system of the secondary combustion chamber. Preferably, a fuel nozzle is provided in the secondary combustion chamber, and the fuel nozzle is electrically connected to the PLC control system of the secondary combustion chamber; Preferably, the exhaust gas outlet of the low-temperature drying unit is connected to a condensation device; Preferably, the non-condensable gas outlet and the condensate outlet of the condensation device are both connected to the secondary combustion chamber; Preferably, the exhaust gas outlets of the intelligent linkage electrified crushing unit and the medium-temperature pyrolysis unit are both connected to the secondary combustion chamber; Preferably, the flue gas outlet of the secondary combustion chamber is connected to a waste heat boiler to generate steam or hot water; Preferably, the outlet of the waste heat boiler is connected to the quench tower; Preferably, the outlet of the quench tower is connected to the dry reaction tower; Preferably, the outlet of the dry reaction tower is connected to a bag filter. Preferably, the air outlet of the bag filter is connected to a multi-stage alkaline spraying device; Preferably, the multi-stage alkaline spraying device includes a first alkaline spraying device and a second alkaline spraying device, wherein the air outlet of the first alkaline spraying device is connected to the second alkaline spraying device.

7. The decommissioned lithium battery recycling system according to any one of claims 1-6, characterized in that, The signal input and signal output terminals of the cloud-based central control unit are respectively electrically connected to the PLC control system of the crusher in the intelligent linkage electrified crushing unit, the PLC control system of the low-temperature drying furnace in the low-temperature drying unit, the PLC control system of the medium-temperature rotary kiln and the cooling rotary kiln in the medium-temperature pyrolysis unit, and the PLC control system of the secondary combustion chamber in the exhaust gas treatment unit.

8. A method for recycling retired lithium batteries based on intelligent control and multi-parameter safety interlocking, characterized in that, The retired lithium battery recycling method adopts the retired lithium battery recycling system based on intelligent control and multi-parameter safety interlock as described in any one of claims 1-7; The method for recycling retired lithium batteries includes the following steps: S1, crush the charged battery cells to obtain the crushed material; S2, the crushed material is dried to obtain the dried material; S3, the dried material is sorted in multiple stages to obtain various components including battery powder; S4, pyrolyze the battery powder, dry the electrolyte and pyrolyze the PVDF in the battery powder; Among them, the exhaust gas generated from crushing, drying and pyrolysis is treated to meet emission standards.

9. The recycling method according to claim 8, characterized in that, The recycling method also includes intelligent control, including: the monitoring devices installed in the crusher, low temperature drying furnace, medium temperature rotary kiln, cooling rotary kiln and secondary combustion chamber respectively transmit the monitored parameter data to their respective PLC control systems via electrical signals; The PLC control system uploads parameter data to the cloud-based central control unit via electrical signals. The cloud-based central control unit stores a database of battery material characteristics. Based on the real-time parameter data and the database, the cloud-based central control unit makes judgments, confirms abnormalities or alarms, obtains the optimal process parameters, and transmits the process parameters to the corresponding PLC control system in the form of electrical signals for regulation.

10. The recycling method according to claim 9, characterized in that, The intelligent control in the crusher includes: When the pressure inside the crushing chamber exceeds 0.12 MPa, the PLC control system uploads the pressure data to the cloud-based central control unit. The cloud-based central control unit determines that the safety threshold has been exceeded, triggers an audible and visual alarm, and sends a process signal to the crusher's PLC control system. This system controls the pressure relief valve to open and controls the double gate valve at the crushing chamber inlet to reduce the feed, thereby reducing the crushing load by 30%-50%. When the VOCs concentration in the crushing chamber is greater than 50ppm, the PLC control system uploads the VOCs concentration data to the cloud central control unit. The cloud central control unit determines that the safety threshold has been exceeded, issues a shutdown warning, and sends the process signal to the crusher's PLC control system, which controls the gas protection device to increase the nitrogen flow rate by 30%-50% and reduce the nitrogen temperature to -20℃ to -40℃. When the oxygen content in the crushing chamber is greater than 5%, the PLC control system uploads the oxygen content data to the cloud central control unit. The cloud central control unit judges the abnormality and sends the process signal to the PLC control system of the crusher, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%. When the temperature inside the crushing chamber exceeds 90℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the crusher's PLC control system, which then controls the gas protection device to increase the nitrogen flow rate by 10%-30%. When the temperature inside the crushing chamber exceeds 120℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends the process signal to the crusher's PLC control system, which then controls the emergency fire-fighting device to activate the emergency fire-fighting water system. When flames appear in the crushing chamber, the PLC control system uploads an electrical signal to the cloud central control unit. The cloud central control unit determines the abnormality and sends a process signal to the crusher's PLC control system to control the emergency fire-fighting device to activate the emergency fire-fighting water. Preferably, the intelligent control in the low-temperature drying oven includes: When the oxygen content inside the furnace exceeds 5%, the PLC control system uploads the oxygen content data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the PLC control system of the low-temperature drying oven, controlling the gas protection device to increase the nitrogen flow rate by 20%-40%. When the temperature inside the furnace exceeds 320℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the PLC control system of the low-temperature drying oven, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%. Preferably, the intelligent control in the medium-temperature rotary kiln includes: When the oxygen content in the medium-temperature rotary kiln is greater than 4%, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the abnormality and sends the process signal to the PLC control system of the medium-temperature rotary kiln, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%. When the temperature inside the medium-temperature rotary kiln exceeds 510℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit detects the anomaly and sends a process signal to the PLC control system of the medium-temperature rotary kiln, controlling the gas protection device to increase the nitrogen flow rate by 30%-50%. Preferably, the intelligent control in the cooling rotary kiln includes: When the material temperature at the outlet of the cooling rotary kiln exceeds 70℃, the temperature data is uploaded to the cloud-based central control unit according to the PLC control system. The cloud-based central control unit determines the abnormality and sends the process signal to the PLC control system of the cooling rotary kiln, controlling the cooling water supply device to increase the cooling water flow rate by 30%-50%. Preferably, the intelligent control in the secondary combustion chamber includes: When the temperature inside the secondary combustion chamber is less than 850℃, the PLC control system uploads the temperature data to the cloud-based central control unit. The cloud-based central control unit determines the abnormality and sends the process signal to the PLC control system of the secondary combustion chamber, controlling the fuel nozzle to increase the natural gas flow by 30%-100%.

Images