In-situ online detection system and method for lithium battery black powder

Abstract

This invention relates to an in-situ online detection system and method for lithium battery black powder. The detection system includes a belt conveyor, on which multiple material boxes are fixedly arranged at equal intervals along the conveyor belt's extension direction. The tops of the material boxes are open. Above the conveyor belt, along the conveying direction, a crushing and feeding device, a pressing device, and a laser-induced breakdown spectroscopy (LASPS) detection device are sequentially arranged. The distance between the center of the discharge port of the crushing and feeding device and the center of the pressing component of the pressing device, and the distance between the center of the pressing component of the pressing device and the focal point of the laser beam of the LASPS detection device, are both integer multiples of the distance between the centers of two adjacent material boxes. The drive motor of the belt conveyor is a stepper motor. The detection method is implemented based on the detection system. This invention enables direct inspection of waste lithium batteries after crushing and sorting, and allows for continuous detection, effectively improving the automation and efficiency of black powder detection.

Description

Technical Field

[0001] This invention relates to an in-situ online detection system and method for lithium battery black powder, belonging to the field of material composition detection technology. Background Technology

[0002] Waste lithium-ion battery black powder is not only rich in high-value strategic metals such as nickel, cobalt, and lithium, but also contains harmful components such as fluorides and organic electrolytes. With the surge in global demand for lithium batteries and the arrival of the retirement wave, efficient recycling of valuable metals from waste lithium battery black powder is the key to resource recycling and sustainable development of the new energy industry.

[0003] To ensure the standardization of black powder production, improve product quality, and provide data support for increasing metal recovery efficiency, reducing secondary pollution, and optimizing processes, it is necessary to use quick and accurate methods to detect and identify various metal elements in the black powder during the recycling process. Traditional detection devices are all offline devices. For example, utility model patent CN221926184U discloses a device for detecting the metal components of recycled battery black powder, including a detection box, an X-ray tube, a miniature spectrometer, and a sample plate. The detection box is equipped with an X-ray reflection chamber, which is triangular prism in shape. A detection groove is opened on the front of the detection box, and the sample plate passes through the detection groove and enters the X-ray reflection chamber. An X-ray inlet communicating with the X-ray reflection chamber is provided on one side of the detection box, and an X-ray collimator is installed on the X-ray tube and inserted into the X-ray inlet. This detection device utilizes an X-ray tube, collimated by a collimating lens, to project X-rays onto a black powder sample within an X-ray reflection chamber, generating characteristic X-rays. A miniature spectrometer detects these characteristic X-rays via the collimating lens, converting them into electrical signals that are transmitted to the operating table and displayed. It features simple and rapid detection steps, high operational stability, and low equipment production costs. However, this device employs an offline detection method, which cannot meet the real-time elemental composition requirements during black powder recovery. The vacuum filtration of the sample box during detection is time-consuming and energy-intensive, increasing the actual operating cost of black powder detection and making it unsuitable for rapid industrial-scale detection scenarios. The sample placement and removal operations are complex, failing to meet the demands of large-scale black powder detection in industrial settings. Furthermore, X-ray detection of black powder components has weak capabilities for detecting light elements and requires stringent sample pretreatment, making accurate quantification of light elements such as lithium impossible. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, this invention provides an in-situ online detection system and method for lithium battery black powder, which can directly inspect waste lithium batteries after crushing and sorting, and can achieve continuous detection, effectively improving the automation level and detection efficiency of black powder detection.

[0005] The technical solution adopted in this invention is: an in-situ online detection system for lithium battery black powder, including a belt conveyor. Multiple material boxes are fixedly arranged at equal intervals along the extension direction of the conveyor belt on its surface. The top of each material box is open. Above the conveyor belt, along the transmission direction, a crushing and feeding device, a pressing device, and a laser-induced breakdown spectroscopy detection device are sequentially arranged. The distance between the center of the discharge port of the crushing and feeding device and the center of the pressing component of the pressing device is an integer multiple of the distance between the centers of two adjacent material boxes. The distance between the center of the pressing component of the pressing device and the focal point of the laser beam of the laser-induced breakdown spectroscopy detection device is an integer multiple of the distance between the centers of two adjacent material boxes. The drive motor of the belt conveyor is a stepper motor.

[0006] Preferably, the crushing and feeding device is a crushing and sorting device in a waste lithium battery crushing and sorting production line, so as to realize in-situ online continuous detection after the waste lithium battery is crushed and sorted.

[0007] Preferably, the crushing and feeding device includes a feeding hopper, a crushing bin, a cyclone separator, and an induced draft fan. The feeding hopper is vertically arranged, and its outlet is connected to the inlet of the crushing bin. The crushing bin is equipped with a crushing impeller inside its cavity, and the crushing impeller is equipped with a crushing impeller drive motor located outside the crushing bin. The outlet of the crushing bin is connected to the inlet of the cyclone separator, and the outlet of the cyclone separator is vertically downward facing the conveyor belt, serving as the outlet of the crushing and feeding device. The exhaust port of the cyclone separator is connected to the induced draft fan through an exhaust pipe.

[0008] Preferably, the discharge port of the cyclone separator is equipped with a screen.

[0009] Preferably, the discharge port of the cyclone separator is equipped with an airlock discharge valve.

[0010] Preferably, the exhaust pipe is equipped with an air volume regulating valve.

[0011] Preferably, the crushing and feeding device is provided with a crushing and feeding device frame, and the feeding hopper, the crushing bin, the cyclone separator, the induced draft fan and the crushing impeller drive motor are all fixedly mounted on the crushing and feeding device frame.

[0012] Preferably, the pressing device includes a hydraulic cylinder and a pressing plate (or pressing head). The hydraulic cylinder is vertically arranged with its piston rod pointing vertically downward. The pressing plate is connected to the bottom end of the piston rod and serves as the pressing component of the pressing device. The bottom surface of the pressing plate is a plane, and the cross-section of the pressing plate is conformally matched to the cross-section of the inner cavity of the material box.

[0013] Preferably, the pressing device is provided with a pressing device frame, and the hydraulic cylinder is fixedly mounted on the pressing device frame.

[0014] Preferably, a vertical guide device is fixedly provided on the frame of the pressing device, the guide device is provided with a vertical guide channel, and the pressing plate is located in the guide channel to ensure the vertical movement of the pressing plate.

[0015] Furthermore, the guiding device consists of two guide posts, which are arranged symmetrically in the left and right vertical directions. The space between the two guide posts forms the guiding channel, and the side wall of the pressure plate slides in conjunction with the inner side wall of the corresponding guide post.

[0016] Preferably, the laser-induced breakdown spectroscopy detection device includes: A laser used to emit pulsed laser beams; A focusing lens, located on the transmission path of the pulsed laser beam, is used to focus the pulsed laser beam onto the surface of the material in the hopper, thereby exciting the material to generate plasma. A collecting lens is used to collect the characteristic spectrum emitted by the plasma radiation of the material and transmit it to the spectrometer; A spectrometer is used to perform photoelectric conversion and analog-to-digital conversion on characteristic spectra to obtain corresponding digital spectral signals.

[0017] Preferably, the laser-induced breakdown spectroscopy detection device is provided with a detection device frame, and the laser, the focusing lens, the collecting lens and the spectrometer are all fixedly mounted on the detection device frame.

[0018] Preferably, an attenuator and a reflector are provided between the laser and the focusing lens along the transmission direction of the laser beam, and both the attenuator and the reflector are fixedly mounted on the frame of the detection device.

[0019] Preferably, a blower is provided at the lower part of the testing device frame, and the air outlet of the blower faces the inside of the testing device frame.

[0020] Preferably, the lithium battery black powder in-situ online detection system further includes a host computer, the signal output of the spectrometer is connected to the host computer, and the host computer is used to perform elemental identification and quantitative analysis of the material based on the received output signal of the spectrometer.

[0021] Preferably, a receiving cylinder is provided below the end of the belt conveyor.

[0022] Preferably, the stepping distance of the stepper motor is the same as the distance between the centers of two adjacent material boxes.

[0023] Preferably, the stepper motor, the airlock unloading valve, the hydraulic cylinder, the laser, and the spectrometer are all controlled by a single-chip microcomputer.

[0024] The in-situ online detection method for lithium battery black powder adopts any of the in-situ online detection systems for lithium battery black powder disclosed in this invention. The detection method involves using a stepper motor to control the intermittent operation of a belt conveyor at equal intervals. When any of the material boxes on the conveyor belt is transported to the area below the crushing and feeding device, the belt conveyor stops running. The crushing and feeding device feeds material into the material box located below it. The pressing device compacts and flattens the material in the material box located below it. The laser-induced breakdown spectroscopy detection device detects the material in the material box located below it. After the belt conveyor stops running for a preset time, it restarts and runs repeatedly, thus achieving industrial-scale in-situ continuous online detection of lithium battery black powder.

[0025] The beneficial effects of this invention are: (1) This invention integrates waste lithium battery crushing and sorting, black powder conveying, black powder pretreatment, black powder LIBS detection and analysis technology into one. After waste lithium battery crushing and sorting, it can be directly put into inspection without manual sampling, transportation and offline sample preparation. It significantly reduces manual intervention and realizes in-situ online continuous detection of lithium battery black powder. It solves the problem of cumbersome process flow of manual sampling, offline sample preparation and separate detection in traditional black powder detection methods. It has the characteristics of high automation, fast detection speed, accurate detection results, and suitability for continuous operation and large-scale industrial operation. (2) Before testing the black powder, the present invention compacts and flattens the black powder sample to be tested by a pressing device to unify the surface height and flatness of the black powder sample to be tested, so that it accurately matches the focusing requirements in the testing process. This can effectively solve the problems of inaccurate focusing and unstable laser action caused by uneven surface height and looseness of the black powder sample to be tested during the testing process. At the same time, the dense testing surface formed by compacting and flattening the black powder sample to be tested can effectively suppress sample splashing during the laser beam impact process, protect the cleanliness of the detection optical path, and further improve the accuracy and stability of the detection data. (3) The present invention, through the combination of laser-induced breakdown spectroscopy detection device and analysis model in host computer, can realize real-time online analysis of spectral signal acquisition, analog-to-digital conversion, feature extraction and element identification. Compared with traditional X-ray spectrometer, it expands the detection range of light elements and significantly shortens the detection cycle, reducing the corresponding process delay. (4) This invention achieves fully automatic operation of the detection system by using a single-chip microcomputer to control the start and stop of the belt conveyor and the positioning, flattening sequence and detection cycle of the black powder sample to be tested, thereby improving the stability and consistency of the system operation. (5) By combining the material box and the conveyor belt, the present invention completely solves the problem of easy spillage and uneven distribution of the black powder sample during the conveying process, and ensures that the sample is filled evenly and conveyed cleanly. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process flow of one embodiment of the lithium battery black powder in-situ online detection system of the present invention; Figure 2 This is a schematic diagram of one embodiment of the crushing and feeding station of the lithium battery black powder in-situ online detection system of the present invention; Figure 3 This is a schematic diagram of the material pressing station of the lithium battery black powder in-situ online detection system of the present invention; Figure 4 This is a schematic diagram of one embodiment of the detection station of the lithium battery black powder in-situ online detection system of the present invention.

[0027] In the diagram, 1-belt conveyor; 2-material box; 3-crushing and feeding device; 301-feeding hopper; 302-crushing bin; 303-cyclone separator; 304-induced draft fan; 305-crushing impeller; 306-crushing impeller drive motor; 307-exhaust pipe; 308-screen; 309-airlock discharge valve; 310-airflow regulating valve; 311-crushing and feeding device frame; 4-pressing device; 401-hydraulic cylinder; 402-pressing plate; 403-pressing device frame; 404-guide column; 5-laser induced breakdown spectroscopy detection device; 501-laser; 502-focusing lens; 503-collecting lens; 504-spectrometer; 505-detection device frame; 506-attenuator; 507-reflector; 508-blower; 6-host computer; 7-collecting cylinder; 8-microcontroller. Detailed Implementation

[0028] See Figure 1This invention discloses an in-situ online detection system for lithium battery black powder, which is mainly used for in-situ online continuous detection of lithium battery black powder. The detection system includes a belt conveyor 1 for conveying black powder samples to be tested. Multiple material boxes 2 are fixedly arranged at equal intervals on the belt surface of the conveyor belt along the extension direction of the conveyor belt. The top of the material box is open for loading the black powder samples to be tested. Above the conveyor belt, along the conveying direction, are sequentially arranged a crushing and feeding device 3, a pressing device 4, and a laser-induced breakdown spectroscopy (LIBS) detection device 5. The crushing and feeding device, the pressing device, and the LIBS detection device are positioned at the crushing and feeding station, the pressing station, and the detection station, respectively, within the detection system. The crushing and feeding device is used to crush and sort waste lithium batteries to obtain black powder to be tested and feed the obtained black powder into the material box. The pressing device is used to press the black powder sample loaded in the material box, compacting and flattening the sample to form a flat and dense detection surface, thereby improving the stability of subsequent laser beam excitation and spectral acquisition. The LIBS detection device is used to perform LIBS detection on the black powder sample loaded in the material box. The distance between the center of the discharge port of the crushing and feeding device and the center of the pressing component of the pressing device is an integer multiple of the distance between the centers of two adjacent material boxes, for example, 5 to 20 times. The distance between the center of the pressing component of the pressing device and the focal point of the laser beam of the laser-induced breakdown spectroscopy detection device is an integer multiple of the distance between the centers of two adjacent material boxes, for example, 5 to 20 times. This ensures that when one material box is transported to the crushing and feeding station to receive feed, other material boxes are simultaneously transported to the pressing and detection stations to receive pressing and detection, thereby realizing continuous operation of crushing and sorting waste lithium batteries and feeding, pressing, and detecting black powder samples to be tested. The drive motor of the belt conveyor is a stepper motor, which controls the intermittent operation (fixed-distance conveying) of the belt conveyor at equal intervals to meet the time required for feeding operations at the crushing and feeding station, pressing operations at the pressing station, and testing operations at the testing station. That is, when the belt conveyor transports a certain material box to the crushing and feeding station, the belt conveyor stops running, and the material box transported to the crushing and feeding station receives feeding operations. At this time, the black powder sample to be tested in the material box transported to the pressing station receives pressing operations, and the black powder sample to be tested in the material box transported to the testing station receives testing operations. After the corresponding material box has completed feeding operations, pressing operations, and testing operations, the belt conveyor starts running. The belt conveyor repeatedly starts and stops in this way to achieve continuous operation.

[0029] The crushing and feeding device is preferably a crushing and sorting device in a waste lithium battery crushing and sorting production line, so as to realize the docking of the waste lithium battery crushing and sorting production line with the black powder detection production line, thereby realizing in-situ online continuous detection of waste lithium batteries after crushing and sorting.

[0030] See Figure 2 The crushing and feeding device preferably includes a feeding hopper 301, a crushing chamber 302, a cyclone separator 303, and an induced draft fan 304. The feeding hopper is vertically arranged and used to feed waste lithium batteries into the crushing and feeding device. The outlet of the feeding hopper is connected to the inlet of the crushing chamber to deliver the fed waste lithium batteries into the crushing chamber. The crushing chamber is equipped with a crushing impeller 305 for crushing the waste lithium batteries fed into the crushing chamber. The crushing impeller is equipped with a crushing impeller drive motor 306 to provide power to the crushing impeller. The crushing impeller drive motor is located outside the crushing chamber. The crushing bin can be replaced by any existing crusher or pulverizer suitable for crushing solid materials. The discharge port of the crushing bin is connected to the inlet of the cyclone separator to send the crushed material into the cyclone separator. The discharge port of the cyclone separator is vertically downward facing the conveyor belt and serves as the discharge port of the crushing feeding device. It is used to discharge the black powder separated from the material from the crushing feeding device and feed it into the corresponding material box on the conveyor belt (the belt conveyor stops running during feeding). The exhaust port of the cyclone separator is connected to the induced draft fan through the exhaust pipe 307 to discharge clean air.

[0031] Preferably, the discharge port of the cyclone separator is equipped with a screen 308 to separate electrode fragments or other unbroken lumpy materials from the material, ensuring the particle size of the discharged black powder to be tested. Preferably, the discharge port of the cyclone separator is equipped with an airlock discharge valve 309 for continuous quantitative discharge and airlock sealing. The black powder to be tested, after being sorted by the cyclone separator, is discharged directly into the material box through the airlock discharge valve. The airlock discharge valve can be an airlock valve, a rotary valve, or an airlock device.

[0032] Preferably, an airflow regulating valve 310 is installed inside the exhaust pipe to regulate the sorting airflow of the cyclone separator. The airflow regulating valve is preferably 5m³ / s. 3 / min~20m 3 / min.

[0033] The crushing and feeding device preferably includes a crushing and feeding device frame 311, which can be fixedly installed on the ground. The feeding hopper, the crushing bin, the cyclone separator, the induced draft fan, and the crushing impeller drive motor are all fixedly installed on the crushing and feeding device frame. The feeding hopper is preferably located at the top of the crushing and feeding device frame, the crushing bin is preferably located below the feeding hopper, the crushing impeller drive motor is preferably located below the crushing bin, the cyclone separator is preferably located to the side of the crushing bin, and the induced draft fan is preferably located to the side of the cyclone separator.

[0034] See Figure 3 The pressing device preferably includes a hydraulic cylinder 401 and a pressing plate (or pressing head) 402. The hydraulic cylinder is vertically arranged to provide pressing power. The pressure of the hydraulic cylinder is preferably adjustable. During pressing, the pressure is preferably 15MPa~20MPa, and the holding time is preferably 10s~15s to adapt to pressing black powder samples with different moisture contents and particle sizes. The piston rod of the hydraulic cylinder is vertically downward, and the pressing plate is horizontally fixed to the bottom end of the piston rod as the pressing component of the pressing device. The bottom surface of the pressing plate is flat so as to better compact and flatten the black powder sample to be tested in the material box. The cross-section of the pressing plate is conformal to the cross-section of the inner cavity of the material box so as to extend into the material box below it to perform omnidirectional pressing operation on the black powder sample to be tested.

[0035] The pressing device preferably has a pressing device frame 403, which can be fixedly installed on the ground. The hydraulic cylinder is fixedly installed on the pressing device frame, usually vertically installed at the top of the pressing device frame.

[0036] Preferably, a vertical guide device is fixedly installed on the frame of the pressing device to guide the pressing plate during the pressing operation, ensuring the vertical movement of the pressing plate. The guide device has a vertical guide channel, and the pressing plate is located within the guide channel. The guide device can be two guide posts 404, which are arranged vertically symmetrically to the left and right. They can be fixedly installed on the frame of the pressing device by corresponding brackets. The space between the two guide posts forms the guide channel. The pressing plate is located between the two guide posts, and the side wall of the pressing plate slides with the inner side wall of the corresponding side of the guide post to guide the pressing plate. The distance between the bottom end of the guide post and the surface of the conveyor belt is preferably the same as the height of the material box, so that when the material box is transported directly below the pressing device, the guide post and the corresponding side wall of the material box are vertically aligned, ensuring that the pressing plate can be accurately guided into the material box to press the black powder sample to be tested in the material box.

[0037] See Figure 4 The laser-induced breakdown spectroscopy detection device preferably includes a laser 501, a focusing lens 502, a collecting lens 503, and a spectrometer 504. The laser is used to emit a pulsed laser beam. The laser can be a neodymium-doped yttrium aluminum garnet solid-state laser. The wavelength of the emitted laser beam is preferably 1064 nm, the output energy is preferably adjustable from 20 mJ to 100 mJ, and the diameter of the focused spot is preferably 200 μm. The focusing lens is located on the transmission path of the pulsed laser beam and is used to focus the pulsed laser beam onto the surface of the black powder sample to be tested in the material box, exciting the black powder sample to generate plasma. The collecting lens is used to collect the characteristic spectrum emitted by the plasma of the black powder sample to be tested and transmit it to the spectrometer. The spectrometer is used to perform photoelectric conversion and analog-to-digital conversion on the characteristic spectrum to obtain the corresponding digital spectral signal. The spectrometer can be a broadband fiber optic spectrometer, the detection range is preferably 200 nm to 800 nm, the integration time is preferably 1 ms, and the resolution is preferably 0.1 nm.

[0038] The laser-induced breakdown spectroscopy detection device preferably includes a detection device frame 505. The material pressing device frame can be fixedly installed on the ground. The laser, the focusing lens, the collecting lens, and the spectrometer are all fixedly mounted on the detection device frame. Depending on the positions of the laser and the focusing lens on the detection device frame, an attenuator 506 and a reflector 507 can be provided between the laser and the focusing lens along the laser beam transmission direction. The attenuator is used to reduce or control the power of the laser beam emitted by the laser, and the reflector is used to change the transmission direction of the laser beam. Both the attenuator and the reflector are fixedly mounted on the detection device frame. Preferably, a blower 508 is provided at the lower part of the detection device frame. The air outlet of the blower faces the inner side of the detection device frame to remove dust generated when the laser beam excites the black powder sample to be detected and to assist in heat dissipation.

[0039] A preferred embodiment of the laser-induced breakdown spectroscopy detection device is as follows: The detection device frame includes a column and upper and lower mounting beams, forming a frame structure. A gap is left between the upper and lower mounting beams. The laser is horizontally fixedly mounted on the upper mounting beam. The attenuator and the reflector are fixedly mounted on the upper mounting beam along the propagation direction of the laser beam emitted by the laser. The laser beam propagates vertically downward after being reflected by the reflector. A vertical beam is fixedly provided between the upper and lower mounting beams. The focusing lens is horizontally fixedly mounted on the vertical beam and located in the propagation path of the laser beam. The collecting lens and the spectrometer are fixedly mounted on the lower mounting beam. The blower is fixedly mounted on the column, and the blower's outlet faces the inside of the detection device frame. The arrangement of the upper, lower, and vertical beams does not affect (or obstruct) the propagation of the laser beam.

[0040] In practical applications, when using the laser to excite the black powder sample to be tested, a 4×4 matrix dotting method is preferred, that is, 16 detection points are set on the surface of the black powder sample to improve the coverage of the detection area and the representativeness of the sample. The laser excites the sample point by point at a frequency of 2Hz, and each detection point is hit 20 times consecutively, so as to generate plasma locally on the surface of the black powder sample. The characteristic spectrum generated by the plasma radiation is received by the spectrometer set next to the excitation area (set on the lower mounting beam), and then photoelectric conversion and analog-to-digital conversion are completed by the CCD in the spectrometer to obtain the corresponding digital spectral signal.

[0041] The detection system preferably also includes a host computer 6, which pre-stores an element identification and quantitative analysis model. The signal output of the spectrometer is connected to the host computer (communication connection). Based on the received output signal from the spectrometer, the host computer performs preprocessing, feature extraction, spectral line identification, and content calculation, thereby realizing real-time online analysis and identification of target metal elements in the black powder sample to be tested (including element type and content identification). Preferably, the host computer can also perform averaging, anomaly removal, or fusion processing on spectra obtained from multiple sampling points and multiple samplings to reduce errors caused by powder inhomogeneity, local looseness, or surface micro-undulations, and improve the stability of the analysis results. The element identification and quantitative analysis model stored in the host computer can employ a suitable spectral analysis model or data processing program under existing technology. The identified target elements may include key metal components in the lithium battery recycling process, such as aluminum, nickel, cobalt, manganese, copper, and iron. The host computer has a human-computer interaction interface for real-time display of detection results; the time from detection to result output is typically no more than 10 seconds.

[0042] Preferably, a receiving cylinder 7 is provided at the lower end of the belt conveyor for automatically collecting the tested black powder samples. As the material box is transported by the conveyor belt to the end of the belt conveyor and passes over the end roller, the black powder sample in the material box is automatically poured into the receiving cylinder, achieving automatic collection of the tested black powder samples. The receiving cylinder has a volume of 50L and a built-in dustproof sealing cover to prevent dust from escaping.

[0043] The stepping distance of the stepper motor is preferably the same as the distance between the centers of two adjacent material boxes, so that when the belt conveyor stops running each time, the corresponding material box can accurately stop at the crushing and feeding station, the pressing station, and the detection station, with a positioning error typically not exceeding 0.5mm.

[0044] The cross-section of the inner cavity of the material box can be rectangular, circular or elliptical, preferably rectangular. The depth of the material box is preferably 10cm to 15cm, so that it can independently load the black powder sample to be tested and prevent the black powder sample to be tested from spilling, shifting or cross-contaminating (mixing with adjacent samples) during transportation.

[0045] The stepper motor, the airlock unloading valve, the hydraulic cylinder, the laser, and the spectrometer are preferably controlled by a single-chip microcomputer (e.g., a 51 microcontroller) to uniformly and automatically control the operation sequence of each station and realize online continuous detection of the black powder sample to be tested.

[0046] This invention also discloses an in-situ online detection method for lithium battery black powder. Using any of the lithium battery black powder in-situ online detection systems disclosed in this invention, the detection method is as follows: A stepper motor controls the belt conveyor to operate intermittently at equal intervals (fixed-distance conveying). When any of the material boxes on the conveyor belt is transported to below the crushing and feeding device, the belt conveyor stops operating. The crushing and feeding device feeds material into the material box located below it. The pressing device compacts and flattens the material in the material box located below it. The laser-induced breakdown spectroscopy detection device detects the material in the material box located below it. After the belt conveyor stops operating for a preset time, it restarts repeatedly. This cyclical operation achieves industrial-scale in-situ continuous online detection of lithium battery black powder.

[0047] When the detection system is activated, a material box is transported to the crushing and feeding station to receive material. If there is no black powder sample to be tested in the material box transported to the pressing station and the detection station, the pressing device and the laser-induced breakdown spectroscopy detection device do not perform pressing and detection operations. Whether the material box transported to the pressing station and the detection station contains the black powder sample to be tested can be determined based on the signals collected by suitable sensors under existing technology, such as infrared sensors or distance sensors.

[0048] The preset time is preferably 10s to 20s to meet the time requirements of the feeding operation at the crushing and feeding station, the pressing operation at the pressing station, and the testing operation at the testing station.

[0049] The operation and running steps of the detection system are as follows: Step 1: Turn on the main power supply of the microcontroller and the host computer, and the system will perform an automatic self-test. The self-test includes: whether the energy output of the laser is stable, with fluctuations not exceeding ±5%; whether the zero position of the belt conveyor has been reset; and whether the dark current and background noise of the spectrometer are normal, with the dark current not exceeding 50 count units. After the self-test passes, the detection system enters standby mode.

[0050] Step Two: Place the waste lithium batteries into the feeding hopper, start the crushing impeller drive motor, and set the motor speed to 1000 rpm to 3000 rpm (adjustable according to material hardness). The waste lithium batteries are crushed by the rotation of the crushing impeller. Simultaneously start the induced draft fan and adjust the airflow regulating valve to stabilize the sorting airflow at 10 m³ / min. 3 / min. The crushed material is separated into black powder and electrode fragments by the cyclone separator. After being sieved through a 50-mesh screen, the black powder particle size does not exceed 0.5mm. The black powder automatically falls into the material box located below through the airlock discharge valve. The filling amount of each material box is usually controlled between 5g and 10g, which is controlled by adjusting the opening and closing time of the airlock discharge valve.

[0051] Step 3: The microcontroller controls the stepper motor to operate, thereby controlling the belt conveyor to operate in a stepping mode. When any of the material boxes on the conveyor belt is transported to the crushing and feeding station, the belt conveyor stops operating, and the crushing and feeding device feeds material into the material box located below it. The pressing device performs a pressing operation on the black powder sample to be tested in the material box transported to the pressing station. Specifically, the hydraulic cylinder drives the pressing plate to descend along the guide column, and holds the pressure at 15MPa for 10s to compact and flatten the black powder sample to be tested, forming a flat and dense testing surface with a surface roughness not exceeding 50μm. The laser-induced breakdown spectroscopy detection device performs detection on the black powder sample to be tested in the material box transported to the detection station. Specifically, the laser is activated, using a 4×4 matrix spotting method with an adjacent spot spacing of 4mm, and is excited point by point at a frequency of 2Hz (the frequency can be adjusted within the range of 1Hz~5Hz). Each detection point is continuously struck 20 times (the number of strikes can be adjusted within the range of 10~30 times). The black powder sample to be tested is excited to generate plasma, and the characteristic emitted light of the plasma is transmitted to the spectrometer through the collecting lens. After the spectrometer completes photoelectric conversion and analog-to-digital conversion, it uploads the spectral data corresponding to each laser pulse to the host computer in real time.

[0052] Step 4: During the shutdown process of the belt conveyor, after each workstation completes its corresponding task, the stepper motor controls the belt conveyor to restart. This cycle repeats to achieve industrial-scale, in-situ, continuous online detection of lithium battery black powder. When the material box (containing the detected black powder sample) is transported to the end of the belt conveyor, the detected black powder sample in the material box automatically falls into the receiving hopper below. An alarm is triggered when the receiving hopper is full, prompting for replacement.

[0053] Step 5: After the inspection is completed, turn off the main power supply and use compressed air or a brush to clean the residual powder in the material box and inside the system. The cleaning cycle can be once every 8 hours.

[0054] During the detection process, if the following situations occur, the detection system will automatically perform corresponding processing: If the signal of the spectrometer is saturated or below the detection limit, the current detection of the black powder sample to be tested is paused and will continue after manual confirmation.

[0055] If the positioning deviation of the conveyor belt exceeds ±1mm, the microcontroller automatically corrects the number of step pulses. If the deviation still exceeds the standard after 3 consecutive corrections, an alarm will be triggered and the machine will stop.

[0056] If the black powder sample to be tested in the material box still has obvious pores on the test surface after being flattened at the pressing station, an additional flattening operation can be performed. If it is still unqualified, the sample is marked as "sample preparation failure" and the test is skipped.

[0057] This invention loads lithium battery black powder into a hopper on a conveyor belt online, completing the shaping and testing of the black powder sample during the transport process. Combined with a host computer, it enables rapid analysis of the metal element composition and content in the black powder sample, making it particularly suitable for large-scale industrial operations of waste lithium battery black powder testing.

[0058] Unless otherwise specified or further limited to one preferred or optional technical means being another, the preferred and optional technical means disclosed in this invention can be arbitrarily combined to form several different technical solutions.

Claims

1. A lithium battery black powder in-situ online detection system, characterized in that The system includes a belt conveyor. Multiple material boxes are fixedly arranged at equal intervals on the surface of the conveyor belt along its extension direction. The tops of the material boxes are open. Above the conveyor belt, along its transmission direction, a crushing and feeding device, a pressing device, and a laser-induced breakdown spectroscopy detection device are sequentially arranged. The distance between the center of the discharge port of the crushing and feeding device and the center of the pressing component of the pressing device is an integer multiple of the distance between the centers of two adjacent material boxes. The distance between the center of the pressing component of the pressing device and the focal point of the laser beam of the laser-induced breakdown spectroscopy detection device is an integer multiple of the distance between the centers of two adjacent material boxes. The drive motor of the belt conveyor is a stepper motor.

2. The lithium battery black powder in-situ online detection system according to claim 1, characterized in that The crushing and feeding device includes a feeding hopper, a crushing bin, a cyclone separator, and an induced draft fan. The feeding hopper is vertically arranged, and its outlet is connected to the inlet of the crushing bin. The crushing bin is equipped with a crushing impeller inside its cavity. The outlet of the crushing bin is connected to the inlet of the cyclone separator. The outlet of the cyclone separator is vertically downward and faces the conveyor belt, serving as the outlet of the crushing and feeding device. The exhaust port of the cyclone separator is connected to the induced draft fan through an exhaust pipe.

3. The lithium battery black powder in-situ online detection system according to claim 2, characterized in that The cyclone separator is equipped with a screen at its discharge port.

4. The lithium battery black powder in-situ online detection system according to claim 2, characterized in that... The cyclone separator is equipped with an airlock discharge valve at its outlet.

5. The lithium battery black powder in-situ online detection system according to claim 1, characterized in that... The pressing device includes a hydraulic cylinder and a pressing plate. The hydraulic cylinder is vertically arranged with its piston rod pointing vertically downward. The pressing plate is connected to the bottom end of the piston rod and serves as the pressing component of the pressing device. The bottom surface of the pressing plate is flat, and the cross-section of the pressing plate is conformally matched to the cross-section of the inner cavity of the material box.

6. The lithium battery black powder in-situ online detection system according to claim 1, characterized in that... The laser-induced breakdown spectroscopy detection device includes: A laser used to emit pulsed laser beams; A focusing lens, located on the transmission path of the pulsed laser beam, is used to focus the pulsed laser beam onto the surface of the material in the hopper, thereby exciting the material to generate plasma. A collecting lens is used to collect the characteristic spectrum emitted by the plasma radiation of the material and transmit it to the spectrometer; A spectrometer is used to perform photoelectric conversion and analog-to-digital conversion on characteristic spectra to obtain corresponding digital spectral signals.

7. The lithium battery black powder in-situ online detection system according to claim 6, characterized in that... It also includes a host computer, the signal output of the spectrometer is connected to the host computer, and the host computer is used to perform elemental identification and quantitative analysis of the material based on the received output signal of the spectrometer.

8. The lithium battery black powder in-situ online detection system according to claim 1, characterized in that... A receiving drum is provided below the end of the belt conveyor.

9. The lithium battery black powder in-situ online detection system according to claim 1, characterized in that... The stepping distance of the stepper motor is the same as the distance between the centers of two adjacent material boxes.

10. A method for in-situ online detection of black powder in lithium batteries, characterized in that... The lithium battery black powder in-situ online detection system according to any one of claims 1-9 is characterized by using the stepper motor to control the belt conveyor to operate intermittently at equal intervals. When any of the material boxes on the conveyor belt is transported to the area below the crushing and feeding device, the belt conveyor stops running, the crushing and feeding device feeds material into the material box located below it, the pressing device compacts and flattens the material in the material box located below it, and the laser-induced breakdown spectroscopy detection device detects the material in the material box located below it. After the belt conveyor stops running for a preset time, it restarts and runs again. This cyclic operation realizes industrial-scale in-situ continuous online detection of lithium battery black powder.

Images