Live-line disassembling method for waste lithium battery

Abstract

The invention discloses a waste lithium battery live-line disassembling method which comprises the following steps: S1, conveying a waste lithium battery in a live-line state to a pretreatment station, acquiring specification characteristics of the waste lithium battery by utilizing a visual identification system, and determining disassembling process parameters according to the specification characteristics; s2, the waste lithium battery to be disassembled is conveyed to a cryogenic inert environment, so that a binder of the waste lithium battery to be disassembled is embrittled; s3, utilizing a visual system to identify cutting path coordinates of the waste lithium battery to be disassembled, and utilizing laser cutting equipment to cut a shell of the waste lithium battery in the cryogenic inert environment according to the cutting path coordinates and the disassembling process parameters, so that the shell is separated from an internal battery core assembly; and S4, removing the cut shell by using a manipulator, and taking out the battery cell assembly. According to the invention, the disassembling efficiency of the waste lithium battery and the purity of the recovered product are obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery recycling, in particular to a method for disassembling a waste lithium battery under electricity. BACKGROUND

[0002] With the explosive growth of new energy vehicles and portable electronic devices, the production and sales of lithium ion batteries have increased dramatically. With it comes the wave of retired waste lithium batteries. Waste lithium batteries contain a large amount of valuable metals (such as lithium, cobalt, nickel, copper, aluminum, etc.) and harmful substances such as electrolyte. If not properly disposed of, it will not only cause serious waste of resources, but also cause irreversible pollution to the environment.

[0003] In the existing lithium battery recycling process, the pretreatment link is crucial. The traditional recycling process usually follows the order of "discharge-disassembly-crushing". Among them, the discharge treatment is a "preliminary process" that must be performed before disassembly. This is because the waste battery (especially the retired power battery) often still has a high voltage and electric energy inside, and if it is directly physically disassembled or crushed, it is easy to cause short circuit, and then lead to thermal runaway, fire and even explosion.

[0004] The current mainstream discharge methods mainly include salt water immersion discharge and external load discharge. Specifically, salt water immersion discharge is to immerse the battery in salt water for short circuit discharge. Although this method has low cost, it takes a very long time (usually several days), and a large amount of waste salt water containing heavy metals and organic matter is difficult to handle, causing serious secondary pollution, and salt water corrosion will pollute the battery shell and pole, reducing the quality of recycled materials.

[0005] External load discharge is to use a discharge cabinet or a resistance box to discharge. This method requires large equipment investment and is cumbersome to operate, and for a large number of waste batteries of different specifications and different residual values, it is difficult to achieve efficient automatic matching discharge.

[0006] In addition, after the discharge is completed, the existing battery disassembly method is usually through manual disassembly or through violent crushing by a crusher. Among them, the manual disassembly method has high labor intensity, and the operator directly contacts the battery containing toxic electrolyte and sharp metal edges, which has health and safety hazards. Although the violent disassembly of the crusher has high efficiency, it mixes the high-value metal shell (usually aluminum or stainless steel) with the internal electrode material (positive and negative electrode powder, separator), which makes the subsequent separation extremely difficult, and the mixing of the metal shell reduces the recovery purity of the positive electrode material.

[0007] Therefore, it is urgent to develop a safe, efficient and environmentally friendly automatic disassembly method for batteries under electricity, which can not only ensure operation safety, but also improve disassembly efficiency, while avoiding environmental pollution. SUMMARY

[0008] The main purpose of the present application is to provide a waste lithium battery live disassembly method, aiming at realizing safe, efficient and environmentally friendly live battery automatic disassembly.

[0009] To achieve the above purpose, the waste lithium battery live disassembly method provided by the present application comprises the following steps:

[0010] S1, the waste lithium battery in the live state is transported to the pretreatment station, the specification characteristics of the waste lithium battery are obtained by using the visual recognition system, and the disassembly process parameters are determined according to the specification characteristics;

[0011] S2, the waste lithium battery to be disassembled is transported into a deep cold inert environment, so that the binder of the waste lithium battery to be disassembled is embrittled;

[0012] S3, the cutting path coordinates of the waste lithium battery to be disassembled are recognized by using a visual system, and under the deep cold inert environment, the shell of the waste lithium battery is cut by using a laser cutting device according to the cutting path coordinates and the disassembly process parameters, so that the shell is separated from the internal cell assembly;

[0013] S4, the shell after cutting is removed by using a manipulator, and the cell assembly is taken out.

[0014] In an embodiment, the specification characteristics include at least one of the type, size and pole position of the waste lithium battery.

[0015] In an embodiment, the disassembly process parameters include laser power and cutting speed, wherein the laser power is 500W to 1500W, and the cutting speed is 10mm / s to 50mm / s.

[0016] In an embodiment, the temperature of the deep cold inert environment is -150℃ to -196℃, and the oxygen concentration of the deep cold inert environment is not higher than 1%.

[0017] In an embodiment, the cutting path coordinates are recognized in step S3, comprising:

[0018] The outer surface of the waste lithium battery to be disassembled is scanned by using a visual system, and the seam characteristics of the shell are extracted;

[0019] The closed cutting path coordinates are generated based on the seam characteristics, and the cutting path coordinates are sent to the laser cutting device.

[0020] In an embodiment, the shell includes a cover plate and a bottom shell, and the seam characteristics of the shell include one of the cover plate seam and the shell weld.

[0021] In an embodiment, the shell after cutting is removed by using a manipulator in step S4, comprising:

[0022] The cover plate of the waste lithium battery separated by cutting is adsorbed and removed by a vacuum chuck;

[0023] The battery cell assembly is grabbed and pulled out by a mechanical gripper.

[0024] In an embodiment, the method for disassembling the waste lithium battery with electricity further comprises:

[0025] Waste gas treatment: collecting and treating the composite waste gas generated by laser cutting.

[0026] In an embodiment, the treatment of the composite waste gas generated by laser cutting comprises:

[0027] The composite waste gas is subjected to fractional condensation to recover organic solvents and obtain non-condensable tail gas;

[0028] The non-condensable tail gas is subjected to regenerative high-temperature oxidation to decompose organic matter and obtain high-temperature flue gas containing fluorides and phosphides; and

[0029] The high-temperature flue gas is subjected to quenching and alkaline liquor spraying to remove acidic components.

[0030] In an embodiment, the waste gas treatment further comprises:

[0031] Deep purification: the flue gas after multi-stage spray absorption treatment is sequentially subjected to physical adsorption, fine filtration and chemical adsorption along the flue gas flow direction, wherein,

[0032] The physical adsorption adsorbs residual volatile organic compounds by activated carbon,

[0033] The fine filtration is used to intercept fine particulate matter,

[0034] The chemical adsorption adsorbs residual trace acidic components by solid adsorbents for fluorine-containing and phosphorus-containing compounds.

[0035] The method for disassembling the waste lithium battery with electricity provided by the present application has the following beneficial effects:

[0036] 1. Safe disassembly of waste lithium batteries with electricity is realized

[0037] By sending the waste battery into a deep cold inert environment (-150℃ to -196℃), the electrolyte inside the battery is completely frozen, and the ion mobility is reduced to zero, so that the battery is in an electrochemical "dormant" state. This mechanism fundamentally blocks the energy release path when a short circuit occurs, and even if physical contact occurs during disassembly, it will not cause thermal runaway or fire. Therefore, the present application completely eliminates the "brine / loaded pre-discharge" process in the traditional process, which is time-consuming, polluting and has a residual electricity risk, and can directly process waste lithium batteries in a full or residual electricity state, significantly improving the processing efficiency.

[0038] 2. Flexible and fine disassembly under visual guidance

[0039] The application can accurately capture the joint characteristics of each battery and generate a dedicated cutting path based on the disassembly logic of "first recognition, then decision" through the visual recognition system. Combined with the high precision and non-contact characteristics of laser cutting technology, accurate depth cutting is achieved. This not only avoids the damage to the internal cells of the battery caused by traditional mechanical crushing, but also solves the industry problem of single production line being difficult to compatible multiple battery models (such as mixed line of square and cylindrical), realizing highly flexible automatic production.

[0040] 3. Realize high-purity separation of shell and cell

[0041] The application utilizes the glass transition characteristics of high molecular materials. In a cryogenic environment, the organic adhesive that originally adheres the shell and the cell undergoes a phase change from a high-elastic state to a very brittle glass state, and the adhesive force is greatly weakened. At this time, combined with laser cutting of the weld, the mechanical hand can easily separate the metal shell and the internal cell assembly. This shell removal process avoids the mixing of aluminum / steel shell fragments into the positive and negative electrode powders from the source, so that the recovered metal shell and cell materials have very high purity, greatly improving the added value of downstream products.

[0042] 4. Suppress secondary pollution

[0043] The whole process of the application is carried out in a low-temperature inert and negative pressure sealed environment. Low temperature effectively inhibits the volatilization of organic solvents in electrolyte, inert gas prevents oxidation and combustion, and negative pressure environment prevents dust overflow. At the same time, for the trace smoke generated by laser cutting, a deep treatment system of "staged condensation-high temperature oxidation-alkali spraying" is matched to realize the resource recovery of organic solvents and the harmless emission of toxic gases, solving the noise, dust and waste liquid pollution problems caused by traditional violent disassembly.

[0044] 5. Low loss and significant economic benefits

[0045] Compared with mechanical sawing or grinding, the laser cutting used in the application is a non-contact processing without tool wear and tear, and the maintenance cost is low. At the same time, since the discharging link and the subsequent complex impurity removal link are omitted, the overall process flow is shortened, the energy utilization is more concentrated, and the disassembly operation cost of single battery is significantly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0047] Figure 1 This is a flowchart illustrating an embodiment of the method for dismantling waste lithium batteries while they are charged according to the present invention.

[0048] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0051] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0052] This invention proposes a method for dismantling waste lithium batteries while they are charged.

[0053] In an embodiment of the present invention, as shown in FIG1, the method for dismantling a used lithium battery while it is charged includes the following steps:

[0054] S1. The waste lithium batteries in a charged state are transported to the pre-processing station, and the specifications and characteristics of the waste lithium batteries are obtained using a visual recognition system. The dismantling process parameters are determined based on the specifications and characteristics.

[0055] The purpose of this step is to solve the problem of automated dismantling caused by the "complex and inconsistent materials" in the recycling of waste lithium batteries.

[0056] In real-world recycling scenarios, collected waste lithium batteries are often from diverse brands and models (such as square aluminum shells and cylindrical steel shells), and their remaining charge status is unknown. Traditional dismantling lines typically require manual pre-sorting and equipment adjustments for individual models, resulting in low efficiency and an inability to adapt to mixed incoming materials. This step introduces intelligent visual recognition technology, essentially giving the dismantling equipment "eyes" and a "brain," enabling it to identify each passing battery. This achieves flexible mixed-flow production, laying the data foundation for subsequent precise laser cutting.

[0057] Specifically, the waste lithium batteries to be dismantled are first transported one by one to the pre-processing station via an automated conveyor line (such as a roller conveyor or belt conveyor). Above or to the side of this station, a high-precision vision recognition system is deployed. This system typically integrates a high-resolution industrial CCD camera, a 3D laser contour scanner, and an image processing unit. As the battery passes through the recognition area, the vision recognition system scans and photographs the battery's appearance, using edge detection, pattern recognition, or deep learning algorithms to extract and analyze the specifications and characteristics of the waste lithium batteries in real time.

[0058] In some embodiments, the specification features primarily include at least one of the type, size, and terminal location of the spent lithium battery.

[0059] Specifically, for type identification, the system first determines the battery's packaging form, such as whether it is a square hard shell, cylindrical, or pouch. Different types of batteries have vastly different outer shell structures and internal core layouts, which directly determine the tone of subsequent cutting strategies.

[0060] For dimensional measurement, the system accurately acquires the battery's length, width, and height data through 3D scanning. Since the thickness of the casing is often positively correlated with the overall size of the battery, the dimensional data will be used to construct the geometric boundaries of the cutting path.

[0061] For electrode positioning, the system accurately identifies the spatial coordinates and orientation of the positive and negative electrodes. Since the electrodes are the key nodes connecting the internal battery cell to the external circuitry, and are also sensitive areas that must be avoided during laser cutting (to prevent short circuits caused by cutting the electrode tabs), accurate electrode positioning ensures safe planning of the cutting path.

[0062] After acquiring the aforementioned specifications, the control system automatically calculates or matches the optimal disassembly process parameters for the current battery based on a pre-set process database. These parameters are not static but rather tailored to each battery. For example, for larger, thicker square aluminum-cased batteries, the system matches higher laser power and slower cutting speed to ensure complete penetration of the casing; while for smaller cylindrical batteries, appropriate rotary cutting parameters are used. In this way, a leap from "blind disassembly" to "intelligent disassembly" is achieved.

[0063] In some embodiments, the disassembly process parameters include laser power and cutting speed.

[0064] Specifically, in this embodiment, the laser power is set to a range of 500W to 1500W, for example, 500W, 600W, 700W, 800W, 900W, 1000W, 1100W, 1200W, 1300W, 1400W, 1500W, etc.

[0065] This power range is set based on a comprehensive consideration of the battery casing material properties (usually aluminum alloy or stainless steel) and thickness (typically between 0.5mm and 2mm). If the laser power is below 500W, the beam energy density is insufficient to instantly vaporize or melt through a thicker metal casing in a single scan, potentially requiring repeated cutting. This not only reduces operational efficiency but also increases heat dissipation to the surrounding area. Conversely, if the laser power exceeds 1500W, while the cutting capability is enhanced, it is highly prone to "overcutting." That is, after the high-energy laser beam cuts through the casing, the remaining energy continues to penetrate into the interior, damaging the insulating film on the surface of the battery cell assembly or even severing the tabs, leading to the risk of internal short circuits. Therefore, controlling the power within the 500W to 1500W range aims to achieve a "just right" depth-limited cut: cleanly cutting through the casing while controlling energy dissipation at the casing level, ensuring the integrity of the internal battery cell.

[0066] Furthermore, in this embodiment, the cutting speed is controlled within the range of 10 mm / s to 50 mm / s, for example, 10 mm / s, 20 mm / s, 30 mm / s, 40 mm / s, 50 mm / s, etc.

[0067] This speed parameter, closely coordinated with laser power, jointly determines the linear energy input during the cutting process. In the special conditions of cryogenic dismantling with charged components, the cutting speed not only affects production capacity but also directly relates to thermal safety. If the cutting speed is below 10 mm / s (too slow), the laser beam's dwell time per unit length is too long, leading to a surge in localized heat accumulation. This not only damages the "embrittlement layer" established in the cryogenic environment but may even cause the frozen electrolyte near the cutting seam to vaporize and splash, posing a safety hazard. If the cutting speed exceeds 50 mm / s (too fast), the interaction time between the laser and the material is insufficient, potentially resulting in incomplete cutting or severe slag buildup at the cut, affecting the subsequent removal of the outer casing by the robotic arm. Therefore, maintaining a speed range of 10 mm / s to 50 mm / s is to minimize the heat-affected zone while ensuring complete cutting, utilizing the cryogenic environment to quickly "quench" the heat generated during cutting and prevent heat conduction into the battery.

[0068] In actual operation, the two parameters mentioned above are dynamically linked. For example, for objects identified as "large-capacity square lithium iron phosphate batteries" (with thicker casings), the system will automatically match a higher power (e.g., 1200W) and a moderate speed; while for objects identified as "cylindrical batteries" (with thin walls), the system will reduce the power (e.g., 600W) and increase the speed, thereby achieving customized and non-destructive disassembly of each battery.

[0069] S2. The waste lithium batteries to be dismantled are transported to a cryogenic inert environment to cause the binder of the waste lithium batteries to become embrittled.

[0070] After the battery specifications are identified and parameters are matched, step S2 is carried out, in which the waste lithium batteries to be dismantled are transported to a cryogenic inert environment, where extremely low temperatures are used to induce physical phase changes in the materials, especially causing the binder inside the battery to become embrittled.

[0071] In practice, the cryogenic process in this embodiment is not a simple static freezing process, but a complex process that includes continuous transport and dynamic environmental control, mainly including sending the battery into the compartment and precise control of the compartment environment.

[0072] First, the battery loading and unloading process is performed. The system-controlled conveyor smoothly transports the visually identified, waste lithium batteries to be dismantled into the cryogenic chamber. To minimize cold loss and prevent external moisture from entering, the cryogenic chamber entrance is typically equipped with a double-layered airlock or a flexible cryogenic curtain. As the batteries pass through, the conveyor belt speed works in conjunction with the access control system to ensure the batteries quickly pass through the transition zone and enter the core cryogenic zone. At this point, the batteries begin to exchange heat from room temperature to ultra-low temperature, and their surface temperature drops rapidly.

[0073] Following this, or simultaneously with the transport process, the injection and regulation of the ambient medium are performed. The cooling system is configured to continuously inject liquid nitrogen into the cryogenic chamber. Liquid nitrogen nozzles are typically positioned at the top or side walls of the chamber, spraying liquid nitrogen in an atomized form. This process utilizes the dual physical effects of liquid nitrogen vaporization: firstly, latent heat cooling. Liquid nitrogen absorbs a significant amount of latent heat of vaporization during its transformation from liquid to gas, thus forcibly lowering the ambient temperature. Secondly, gas displacement. The expansion in volume after liquid nitrogen vaporization creates a positive pressure in the resulting cryogenic nitrogen gas flow, actively expelling the oxygen-containing air from the chamber.

[0074] The control system performs closed-loop monitoring of this injection process until the environmental indicators within the cryogenic chamber reach the preset "safety-embrittlement" balance point: that is, the temperature of the cryogenic chamber must be below -150°C, and the oxygen concentration must be below 1%. Only when both conditions are met simultaneously will the control system determine that the cryogenic environment construction is complete. In this state, the low temperature below -150°C ensures that the electrolyte inside the battery is completely frozen and the binder is thoroughly embrittled, meeting the hardness requirements for "physical disassembly"; while the oxygen concentration below 1% ensures that even if the battery occasionally sparks during subsequent cutting, it will not ignite due to the lack of accelerant, meeting the inherent safety requirements for "live-line work".

[0075] In some preferred embodiments of the present invention, the parameters of the cryogenic inert environment are controlled such that the temperature is maintained between -150°C and -196°C and the oxygen concentration is not higher than 1%.

[0076] First, regarding the impact of ultra-low temperature environments ranging from -150℃ to -196℃ on the physical state of batteries. At these extreme temperatures, batteries undergo two key physical changes, resulting in a transformation from "active" to "dormant" and from "tough" to "brittle." The first is the "dormant" state of electrochemical activity. The liquid organic electrolyte inside the battery completely solidifies and crystallizes at this temperature, reducing its ionic conductivity to near zero. This means that lithium ions cannot migrate between the positive and negative electrodes. Even if subsequent laser cutting causes physical contact (short circuit) between the positive and negative electrodes, a sustained short-circuit current cannot be formed, thus eliminating the energy basis for thermal runaway. The second is the "glass transition" of polymer materials. The adhesive (PVDF) used to bond electrode materials and the separator between the positive and negative electrodes in lithium batteries are in a highly elastic state at room temperature, exhibiting strong toughness and adhesion. However, when the temperature drops below their glass transition temperature (Tg), these polymer materials undergo a phase transition from the highly elastic state to the glassy state. The adhesive in the glassy state loses its stickiness and becomes extremely brittle, resulting in a significant decrease in the interfacial bonding force between the battery cell assembly and the metal casing. This embrittlement effect means that the casing and the internal core are no longer a tightly bonded whole, creating the physical conditions for easy decoupling after subsequent laser cutting.

[0077] Secondly, regarding the control of the inert atmosphere with an oxygen concentration not exceeding 1%. Besides low temperature, a low-oxygen environment is equally crucial. The positive pressure environment created by liquid nitrogen vaporization reduces the oxygen content inside the chamber to below the combustion limit. This measure provides double protection: even in extreme unexpected situations (such as when there is still a trace amount of localized heat release inside the battery), the lack of an oxidizer (oxygen) prevents combustion from occurring or spreading.

[0078] In terms of specific control logic, temperature sensors and oxygen analyzers are deployed inside the cryogenic chamber. The control system adjusts the opening of the liquid nitrogen solenoid valve based on real-time feedback data: when the temperature is above -150℃ or the oxygen concentration is above 1%, the liquid nitrogen injection flow rate is increased; when it reaches -196℃ (the boiling point of liquid nitrogen), a small injection is maintained to compensate for cooling loss. Through this dynamic balance, it is ensured that each battery to be disassembled can complete cryogenic treatment in the most suitable cryogenic inert environment.

[0079] S3. Using a vision system, identify the cutting path coordinates of the waste lithium battery to be dismantled. In the cryogenic inert environment, based on the cutting path coordinates and the dismantling process parameters, use a laser cutting device to cut the casing of the waste lithium battery, so that the casing is separated from the internal battery cell assembly.

[0080] Step S3 aims to use a vision system to identify the cutting path and to perform a precise "shelling" operation using laser cutting equipment while maintaining a low temperature and inert atmosphere.

[0081] Specifically, firstly, high-precision visual positioning and path planning are performed. Although the battery specifications have been obtained in step S1, the battery's position may slightly shift when it arrives at the cutting station after cryogenic transport. Therefore, the system restarts the vision system (typically equipped with a high-resolution camera or low-temperature sensor through the cryogenic chamber's observation window) to scan the waste lithium battery to be disassembled in real time. The vision system captures the geometric features of the battery casing surface, especially the seams, welds, or sealing lines. Based on these features, the image processing algorithm accurately calculates the three-dimensional spatial coordinates of the cutting trajectory, i.e., the cutting path coordinates, through edge fitting. This dynamic correction process ensures that the laser beam can scan along the assembly gaps or predetermined opening lines of the casing without error, avoiding deviation from the path and damaging the battery cell.

[0082] In some embodiments, identifying the cutting path includes the following steps:

[0083] S31. Use a vision system to scan the outer surface of the waste lithium battery to be dismantled and extract the seam features of the casing.

[0084] Specifically, a vision system (typically comprising a high-precision line laser profilometer or a high-resolution industrial camera) is configured to perform a 360-degree scan of the outer surface of the spent lithium-ion batteries to be dismantled. Because spent lithium-ion batteries may be slightly misaligned on the conveyor belt within the cryogenic chamber, or because different batches of batteries may have variations in manufacturing tolerances, the vision system must capture the actual shape of the battery in real time. During the scanning process, the image processing algorithm focuses on the seam features of the casing.

[0085] The casing described here is typically assembled from a bottom shell that houses the battery cell and a top cover plate. The connection between these two is called the cover plate seam or casing weld. The vision system extracts this fine seam line from the background by recognizing abrupt changes in grayscale, height differences, or texture variations in the image.

[0086] S32. Based on the joint features, a closed cutting path coordinate is generated, and the cutting path coordinate is sent to the laser cutting device.

[0087] Specifically, the raw extracted seam image data may contain noise or breakpoints, making it unsuitable for direct laser control. Therefore, the control system utilizes an algorithm to perform mathematical fitting based on the seam features. The algorithm fits discrete seam pixels into smooth straight line segments or arc segments, ultimately connecting them to generate a closed cutting path coordinate system. This "closed" path means the laser beam will completely circle around the cover plate, ensuring the physical connection between the cover plate and the bottom shell is completely severed, with no adhesion points. Finally, the control system sends this set of fitted and corrected cutting path coordinates, precisely corresponding to the current battery pose, to the galvanometer control card or motion platform of the laser cutting equipment in real time, guiding the high-energy laser beam along this path for millisecond-level precise cutting, achieving truly intelligent and flexible disassembly.

[0088] Next, laser cutting is performed in a cryogenic environment. Maintaining a constant cryogenic inert environment (-150°C to -196°C, oxygen <1%), the control system invokes the disassembly process parameters determined in step S1 based on the battery specifications (including laser power of 500W-1500W and cutting speed of 10mm / s-50mm / s), instructing the laser cutting equipment to begin operation. The high-energy laser beam emitted by the laser (such as a fiber laser) moves at high speed across the surface of the battery casing, based on the cutting path coordinates generated by the aforementioned vision system.

[0089] During this process, the cryogenic environment plays a crucial role in thermal suppression: when the laser beam is focused on the metal casing, the local metal melts or vaporizes instantly, forming a kerf. At this time, the ultra-low temperature nitrogen gas flowing inside the cryogenic chamber quickly carries away the heat around the kerf, achieving an excellent "quenching" effect. This not only prevents the cutting heat from being conducted inward and damaging the battery cell diaphragm, but also effectively disperses the molten slag, preventing it from re-adheding.

[0090] Finally, as the laser beam completes its closed cutting path, the casing of the waste lithium battery (usually the top cover or side weld) is smoothly cut off, thus achieving complete physical separation between the casing and the internal battery cell assembly, preparing for subsequent mechanical removal processes. The entire process involves no tool wear, no mechanical compression, and is always under intrinsically safe cryogenic inert protection.

[0091] S4. Use a robotic arm to remove the cut outer casing and take out the battery cell assembly.

[0092] Specifically, after the laser cutting equipment completes the cutting of the outer casing according to the path planned by vision, the waste lithium battery enters the physical separation stage, namely step S4, in which a robotic arm removes the cut outer casing in a cryogenic environment and takes out the internal battery cell components without damage.

[0093] In some embodiments, step S4 includes steps S41 and S42.

[0094] S41. Use a vacuum suction cup to adsorb and remove the cover plate of the cut and separated waste lithium battery.

[0095] Specifically, since the laser beam has precisely severed the weld connection between the top cover and the bottom shell of the battery in step S3, the cover is now in a "free" state, only covering the top of the battery.

[0096] To this end, the system controls a robotic arm equipped with a vacuum suction cup to move above the battery. This vacuum suction cup is made of a special low-temperature resistant silicone rubber or fluororubber, which maintains elasticity and sealing in cryogenic environments. The robotic arm presses down, causing the suction cup to adhere to the cover surface, activating a vacuum generator to create negative pressure, firmly adsorbing and removing the cover of the cut and separated waste lithium battery. The removed cover (typically rich in copper, aluminum, and nickel) is directly placed into the metal recycling channel, achieving the first stage of diversion of high-value metals.

[0097] S42. Use mechanical grippers to grasp and pull out the battery cell assembly.

[0098] Specifically, after the cover is removed, the battery cell assembly (a combination of wound or stacked positive and negative electrode plates and a separator) inside the battery is exposed. At this point, the robotic arm switches its end effector or another collaborative robot is activated to use mechanical grippers (such as internal support grippers or finger grippers) to reach into the opened casing or to hold the exposed tabs of the battery cell.

[0099] In this process, the cryogenic embrittlement effect of the preceding step S2 plays a crucial role: due to the glass transition of the adhesive, which causes it to lose its adhesiveness, and the difference in thermal shrinkage rates between different materials caused by the low temperature (the shrinkage rate of the metal shell is generally less than that of the polymer separator and electrolyte complex), the battery cell assembly, which was originally tightly attached to the shell wall, becomes loose, creating a tiny physical gap between it and the shell. Taking advantage of this, the mechanical grippers can easily grasp and pull out the battery cell assembly without using brute force or chemical solvents to dissolve it. The removed battery cell assembly retains its complete physical structure and is then sent to the crushing stage, while the remaining bottom shell (aluminum or steel shell) is recycled as another single metal, thus achieving a truly charged, non-destructive, and precise disassembly.

[0100] In some embodiments, the method for dismantling used lithium batteries while they are charged according to this application further includes:

[0101] S5. Waste gas treatment: Collect and treat the composite waste gas generated by laser cutting.

[0102] Specifically, although laser cutting is performed at low temperatures, the instantaneous thermal interaction between the high-energy beam and battery materials (including residual electrolyte, plastic separator, and metal) inevitably generates a small amount of smoke and chemical vapor. To ensure the green and environmentally friendly nature of the process, the dismantling method in this application also collects and treats the composite waste gas generated by laser cutting.

[0103] Specifically, in step S5, the treatment of the composite waste gas generated by laser cutting includes steps S51 to S53.

[0104] S51. The composite waste gas is staged and condensed to recover organic solvents and obtain non-condensable tail gas.

[0105] Specifically, the exhaust gas generated by cryogenic laser cutting is first extracted by a negative pressure pipeline and sent to a staged condensation unit. Since the main organic components in the exhaust gas are volatile electrolyte solvents (such as dimethyl carbonate (DMC) and ethylene carbonate (EC), and considering the differences in boiling points of different organic solvents (e.g., ethylene carbonate EC has a higher boiling point, while dimethyl carbonate (DMC) has a lower boiling point), this embodiment adopts a "staged condensation" strategy. The exhaust gas sequentially passes through condensers with different temperature gradients (e.g., first-stage 5℃-10℃ cold water condensation, second-stage -20℃ to -30℃ cryogenic condensation, and third-stage -65℃ to -75℃ cryogenic condensation). During this process, most of the high-concentration organic solvents are liquefied and intercepted, and then flow back into the solvent storage tank for recycling. This not only reduces the load on subsequent treatments but also achieves resource regeneration. After condensation, the remaining exhaust gas mainly consists of nitrogen (carrier gas), uncondensed low-boiling-point VOCs, and acidic gases, and is referred to as "non-condensable tail gas."

[0106] S52. The non-condensable tail gas is subjected to regenerative high-temperature oxidation to decompose organic matter and obtain high-temperature flue gas containing fluorides and phosphides.

[0107] Specifically, the non-condensable exhaust gas still contains a small amount of residual volatile organic compounds (VOCs) and possibly trace amounts of odorous gases after condensation. At this point, the gas is fed into a regenerative thermal oxidizer (RTO). As a parallel implementation, a direct-fired incinerator (TO) can also be used, but the RTO has higher thermal efficiency when treating large volumes of low-concentration exhaust gas. Inside the RTO, an auxiliary burner maintains the furnace temperature in the high-temperature range of 800°C to 950°C. Under these high-temperature and sufficient oxygen conditions, the residual alkanes, olefins, and other organic components in the exhaust gas are completely oxidized and decomposed into carbon dioxide (CO2) and water (H2O).

[0108] It is important to note that because the exhaust gas contains fluorine-containing components (from PVDF / LiPF6) and phosphorus-containing components (from LiPF6), these components are converted into hydrogen fluoride (HF) gas and phosphorus pentoxide (P2O5) particles (or phosphoric acid mist) during the high-temperature oxidation process. Therefore, the gas discharged from the RTO at this point is no longer ordinary flue gas, but rather high-temperature acidic flue gas containing fluorides and phosphides. Although the organic toxicity is eliminated, the flue gas at this stage is acidic and corrosive and cannot be directly emitted.

[0109] S53. The high-temperature flue gas is rapidly cooled and sprayed with alkaline solution to remove acidic components.

[0110] Specifically, the high-temperature flue gas from the RTO immediately enters the quenching and alkali spraying tower.

[0111] The flue gas first enters the quench tower, where cooling water or dilute alkali solution is sprayed to rapidly reduce the flue gas temperature from 800°C to below 200°C within a very short time (e.g., within 1 second). This "quenching" process is crucial, as it effectively inhibits the resynthesis of dioxins in the 250°C-500°C temperature range, eliminating the risk of secondary pollution.

[0112] The cooled flue gas then enters a multi-stage counter-current alkaline scrubbing tower. Inside the tower, the flue gas flows upwards, coming into full contact with the alkaline absorbent (such as sodium hydroxide NaOH solution or calcium hydroxide Ca(OH)2 suspension) sprayed downwards. During this process, a vigorous acid-base neutralization reaction occurs: gaseous hydrogen fluoride is fixed as sodium fluoride (NaF) or calcium fluoride (CaF2) precipitate; phosphoric acid, formed by the reaction of phosphorus pentoxide with water, is also neutralized into phosphate. After multi-stage scrubbing, the acidic components in the flue gas are completely removed, converted into harmless salt solutions or precipitates, thus completing the deep acid removal treatment of the waste gas.

[0113] After undergoing these three rigorous processes, the gas emitted from the exhaust pipe fully complies with stringent air pollutant emission standards.

[0114] Although the majority of acidic components in the flue gas have been neutralized and removed through multi-stage alkaline spraying in step S53, this invention further incorporates a deep purification step to meet increasingly stringent environmental emission standards (such as "ultra-low emission" requirements) and to prevent trace pollutants from escaping due to fluctuations in operating conditions. This step aims to capture trace acidic molecules remaining in the wet scrubbing process due to gas-liquid balance limitations, as well as trace amounts of volatile organic compounds (VOCs) and fine particulate matter that may escape. The treatment process is carried out sequentially along the flue gas flow direction in an integrated deep purification tower or a series of independent purification units.

[0115] Specifically, the deep purification steps include: physical adsorption, fine filtration and chemical adsorption sequentially applied to the flue gas after multi-stage spray absorption treatment along the flue gas flow direction. Among them, physical adsorption uses activated carbon to adsorb residual volatile organic compounds, fine filtration is used to intercept fine particulate matter, and chemical adsorption uses solid adsorbents targeting fluorine and phosphorus compounds to adsorb residual trace acidic components.

[0116] First, the flue gas enters the physical adsorption unit. Although the upstream RTO furnace has oxidized and decomposed the organic matter, trace amounts of VOCs may not be completely burned during system startup, shutdown, or fluctuations in operating conditions. This unit uses an activated carbon adsorption bed as its core component.

[0117] Specifically, activated carbon's highly developed pore structure (specific surface area typically greater than 1000 m^2 / g) is utilized to physically capture residual non-polar or weakly polar organic molecules in flue gas. It's worth noting that, for scenarios with large air volumes and continuous operation, a zeolite rotor adsorption and concentration device can also be used as a parallel embodiment. Zeolite molecular sieves are non-flammable, offering higher safety compared to activated carbon, and can be regenerated through thermal desorption, making them suitable for treating low-concentration residual organic waste gas.

[0118] Next, the flue gas passes through a fine filtration unit. The main task of this unit is to intercept solid suspended particles in the flue gas (such as the tiny ash particles produced by RTO combustion) and salt aerosols that may be carried out during the previous stage of alkaline spraying.

[0119] Specifically, this embodiment preferably uses a bag filter or a high-efficiency particulate air (HEPA) filter. The filter media is made of acid and alkali resistant PTFE (polytetrafluoroethylene) membrane filter media, with a filtration accuracy of 0.1μm to 0.5μm, ensuring that the discharged gas is visually smoke-free and physically dust-free.

[0120] Finally, the flue gas enters the chemical adsorption unit, which is specifically designed to remove trace amounts of fluorine (HF) and phosphorus (such as phosphoric acid mist or fluorophosphate) compounds that are difficult to remove completely by traditional alkaline washing.

[0121] Specifically, the flue gas passes through a fixed bed filled with a solid adsorbent. The solid adsorbent used in this embodiment is specifically formulated for acidic gases. Unlike physical adsorption, irreversible chemical adsorption occurs here. The active sites on the surface of the solid adsorbent react chemically with residual HF molecules in the flue gas to generate stable solid fluorides (such as AlF3 or CaF2). This solid-phase reaction is not limited by the gas-liquid equilibrium partial pressure and can reduce the fluoride concentration in the flue gas to the ppb (parts per billion) level.

[0122] In some preferred embodiments, the solid adsorbent employs a dual-effect composite structure, which is composed of a main component (matrix) and an auxiliary component (activity enhancer).

[0123] Specifically, the matrix of the adsorbent is mainly selected from at least one of metal oxides (such as calcium oxide CaO, magnesium oxide MgO, activated alumina Al2O3) or modified activated carbon (activated carbon loaded with KOH or NaOH).

[0124] Furthermore, in this embodiment, the mass percentage of the main component is set to be no less than 90%. Specifically, the main component constitutes the skeleton of the adsorbent and provides a large number of alkaline active sites. Although the concentration of acidic components (HF) in the flue gas is low, the total amount still requires the consumption of stoichiometric reactants. Therefore, the alkaline matrix of more than 90% ensures that the adsorbent has an extremely high acid capacity and can fix acidic gases for a long time through acid-base neutralization reactions (e.g., CaO + 2HF → CaF2 + H2O), thus ensuring the service life and replacement cycle of the adsorbent.

[0125] Secondly, in order to overcome the problem of slow adsorption rate and easy desorption of traditional metal oxides under low partial pressure, this embodiment incorporates an auxiliary component with a mass percentage of no more than 10% into the matrix. This auxiliary component is selected from at least one of phosphates (preferably hydroxyapatite HAP) and rare earth elements (preferably oxides or carbonates of lanthanum (La) and cerium (Ce)).

[0126] Specifically, rare earth elements have an extremely strong affinity for fluoride ions. Doping with trace amounts of lanthanides can form highly active superadsorption sites on the adsorbent surface. When the concentration of residual HF molecules in flue gas is extremely low and difficult to capture through conventional diffusion, these rare earth sites can rapidly capture fluoride ions like magnets, generating extremely insoluble and thermally stable rare earth fluorides (such as LaF3), thereby significantly improving the adsorption rate and purification depth at low concentrations.

[0127] Furthermore, the introduced hydroxyapatite can undergo a lattice substitution reaction with fluoride ions to generate more stable fluorapatite. This reaction is not only irreversible, but the resulting product also has high hardness and resistance to pulverization, avoiding the risk of secondary pollution after adsorption saturation.

[0128] In specific preparation, the above-mentioned auxiliary components can be uniformly dispersed in the porous structure of the main component through co-precipitation or impregnation methods. After extrusion granulation and high-temperature calcination activation, spherical or strip-shaped particles with rich mesoporous structures are produced. This composite adsorbent combines the "large capacity" of metal oxides with the "high precision" of rare earth / phosphates, perfectly matching the process requirements of deep purification.

[0129] Furthermore, in order to ensure the adsorption efficiency and service life of the solid adsorbent in the deep purification step, this embodiment specifically adds a temperature regulation and dehumidification step after the multi-stage spray absorption treatment and before the deep purification.

[0130] In step S53, the high-temperature flue gas is cooled by direct spraying with alkaline solution. Although the temperature is significantly reduced, it usually remains around 50°C to 60°C and is saturated with water vapor. If this "warm and humid gas" is directly introduced into the solid adsorption bed of the deep purification step, two serious problems will arise:

[0131] Firstly, physical adsorption (especially activated carbon adsorption) is usually an exothermic process. According to thermodynamic principles, higher inlet air temperatures will significantly reduce the adsorption equilibrium capacity and may even lead to the thermal desorption of adsorbed pollutants.

[0132] Secondly, saturated water vapor condenses when it comes into contact with the surface of the adsorbent at a lower temperature, forming a "water film" that covers the micropores of the adsorbent. This leads to a "pore competition" effect, where water molecules occupy the active sites that should be used to adsorb fluorides or organic matter, and may even cause the adsorbent to pulverize and become ineffective.

[0133] Therefore, the method of this application explicitly requires that the temperature of the flue gas after multi-stage spray absorption treatment be controlled not to exceed 40°C.

[0134] In practice, a demister cooler or tubular condenser is installed between the spray tower and the deep purification unit. When saturated flue gas flows through this cooling unit, the flue gas temperature is forcibly reduced to below 40°C (preferably within the ambient temperature range of 25°C to 35°C) through indirect heat exchange with circulating cooling water. During this cooling process, a large amount of supersaturated water vapor in the flue gas condenses into droplets and is discharged through a gas-liquid separation device. After this treatment, the flue gas entering the subsequent deep purification unit is transformed into a cool gas with lower relative humidity. This state is not only most conducive to the forward progress of physical and chemical adsorption reactions, maximizing the "working performance" of the solid adsorbent, but also effectively prevents the risk of spontaneous combustion or mold caking of the activated carbon bed due to high temperature and humidity, thereby ensuring the long-term stable operation of the entire environmental protection system.

[0135] In summary, the method for dismantling used lithium batteries while they are charged, as provided in this application, has the following beneficial effects:

[0136] 1. Enabled safe live-line dismantling of used lithium batteries.

[0137] By placing spent batteries in a cryogenic inert environment (-150°C to -196°C), the electrolyte inside the battery completely solidifies, reducing ion mobility to zero, thus putting the battery into an electrochemical "dormant" state. This mechanism fundamentally blocks the energy release pathway in the event of a short circuit, and even if physical contact occurs during disassembly, it will not trigger thermal runaway or fire. Therefore, this application completely eliminates the time-consuming, polluting, and residual charge risk "saltwater / load pre-discharge" process in traditional methods, enabling direct processing of fully charged or partially charged spent lithium batteries, significantly improving processing efficiency.

[0138] 2. Visually Guided Flexible and Refined Decomposition

[0139] This application utilizes a visual recognition system, based on a "recognize first, decide later" disassembly logic, to accurately capture the seam features of each battery and generate a unique cutting path. Combined with the high precision and non-contact characteristics of laser cutting technology, it achieves precise, fixed-depth cutting. This not only avoids damage to the internal cells of the battery caused by traditional mechanical crushing but also solves the industry problem of a single production line being unable to accommodate multiple battery models (such as mixed lines for square and cylindrical batteries), enabling highly flexible automated production.

[0140] 3. Achieve high-purity separation between the outer casing and the battery cell.

[0141] This application utilizes the glass transition properties of polymer materials. Under cryogenic conditions, the organic adhesive that originally binds the outer shell and the battery cell undergoes a phase transition, changing from a highly elastic state to an extremely brittle glassy state, resulting in a significant loss of adhesion. At this point, combined with laser-cut weld seams, a robotic arm can easily and completely separate the metal outer shell from the internal battery cell assembly. This shell removal process prevents aluminum / steel shell fragments from contaminating the positive and negative electrode powders, ensuring that both the recovered metal outer shell and battery cell materials possess extremely high purity, significantly increasing the added value of downstream products.

[0142] 4. Suppress secondary pollution

[0143] The entire process of this application is carried out in a low-temperature, inert, and negative-pressure sealed environment. The low temperature effectively inhibits the volatilization of organic solvents in the electrolyte, the inert gas prevents oxidation and combustion, and the negative-pressure environment prevents dust leakage. At the same time, for the trace fumes generated by laser cutting, a deep treatment system of "staged condensation - high-temperature oxidation - alkaline spraying" is provided, realizing the resource recovery of organic solvents and the harmless emission of toxic gases, solving the noise, dust, and waste liquid pollution problems caused by traditional violent dismantling.

[0144] 5. Low loss and significant economic benefits.

[0145] Compared to mechanical sawing or grinding, the laser cutting method used in this application is a non-contact processing method, eliminating tool wear and reducing maintenance costs. Furthermore, by eliminating the discharge stage and subsequent complex impurity removal processes, the overall process flow is shortened, energy utilization is more concentrated, and the dismantling and operation costs of individual batteries are significantly reduced.

[0146] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for charged disassembly of waste lithium batteries, characterized in that, The method comprises the following steps: S1, delivering the waste lithium battery in a charged state to a pretreatment station, acquiring the specification characteristics of the waste lithium battery by using a visual recognition system, and determining disassembly process parameters according to the specification characteristics; S2, delivering the waste lithium battery to be disassembled into a deep-cooling inert environment to cause the binder of the waste lithium battery to be disassembled to become brittle; S3, identifying the cutting path coordinates of the waste lithium battery to be disassembled by using a visual system, and cutting the shell of the waste lithium battery by using a laser cutting device according to the cutting path coordinates and the disassembly process parameters in the deep-cooling inert environment, so as to separate the shell from the internal cell assembly; S4, removing the cut shell by using a mechanical hand and taking out the cell assembly.

2. The method of claim 1, wherein the method further comprises: The specification characteristics include at least one of the type, size and pole position of the waste lithium battery. ​ 3.The method of claim 1, wherein the step of disassembling the used lithium battery is performed while the used lithium battery is charged. The disassembly process parameters include laser power and cutting speed, wherein the laser power is 500 W to 1500 W, and the cutting speed is 10 mm / s to 50 mm / s.

4. The method for dismantling waste lithium batteries while they are charged, as described in claim 1, is characterized in that... The temperature of the deep-cooling inert environment is -150°C to -196°C, and the oxygen concentration of the deep-cooling inert environment is not higher than 1%.

5. The method of claim 1, wherein the method further comprises: determining whether the lithium battery is in a charged state; and if the lithium battery is in the charged state, discharging the lithium battery to a predetermined voltage level. In step S3, the cutting path coordinates are identified, comprising: scanning the outer surface of the waste lithium battery to be disassembled by using a visual system to extract the joint characteristics of the shell; generating closed cutting path coordinates based on the joint characteristics, and sending the cutting path coordinates to the laser cutting device. 6.The method of claim 5, wherein the step of disassembling the used lithium battery is performed while the used lithium battery is charged. The shell includes a cover plate and a bottom shell, and the joint characteristics of the shell include one of the cover plate joint and the shell weld.

7. The method for dismantling waste lithium batteries while they are charged, as described in claim 1, is characterized in that... In step S4, the cut shell is removed by using a mechanical hand, comprising: absorbing and removing the cut and separated cover plate of the waste lithium battery by using a vacuum chuck; grabbing and pulling out the cell assembly by using a mechanical gripper.

8. The method for dismantling waste lithium batteries while they are charged, as described in claim 1, is characterized in that... The waste lithium battery disassembly method further comprises: waste gas treatment: collecting and treating the composite waste gas generated by laser cutting. 9.The method of recycling waste lithium battery of claim 8, wherein, The treatment of the composite waste gas generated by laser cutting comprises: grading condensation of the composite waste gas to recover organic solvents and obtain non-condensable tail gas; heat accumulating high temperature oxidation of the non-condensable tail gas to decompose organic matter and obtain high temperature flue gas containing fluorides and phosphides; and quenching and alkali spraying of the high temperature flue gas to remove acidic components.

10. The method of claim 9, wherein the lithium battery is a lithium ion battery. The waste gas treatment further comprises: deep purification: physical adsorption, fine filtration and chemical adsorption of the flue gas after multi-stage spray absorption treatment in sequence along the flue gas flow direction, wherein, the physical adsorption adsorbs residual volatile organic compounds by using activated carbon, the fine filtration is used to intercept fine particulate matter, the chemical adsorption adsorbs residual trace acidic components by using solid adsorbents containing fluorine and phosphorus compounds.

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