242 results about "Metallic foreign body" patented technology

The invention relates to the technical field of wireless charging, and provides a foreign matter detection method and system for a wireless charging system and a storage medium. The method comprises the following steps: firstly, calibrating at multiple temperature points and establishing a temperature-parameter comparison table under the condition of no foreign matters; in a no-load standby state, the inversion module sends out detection drive and collects voltage, current and temperature; calculating a real-time quality factor and resonant frequency according to sampling, obtaining a compensation reference according to a temperature look-up table, and solving the variation of the quality factor and the resonant frequency; and performing fusion judgment by adopting dual-condition locking or weighted scoring, and triggering fault protection when a foreign matter is confirmed. Due to the fact that equivalent inductance and resistance changes are caused by metal foreign matters, quality factors are remarkably reduced along with resonant frequency deviation, temperature excursion and foreign matter effects are distinguished through temperature compensation, and dual-condition locking or weighted scoring fusion judgment is combined, the interference immunity and accuracy of detection are improved, false alarms and missing alarms are remarkably reduced, and the detection accuracy is improved. The method is suitable for high-power wireless charging scenes.

The invention provides a wireless charging power-off protection method for detecting metal foreign matters based on signal change, which comprises the following steps: monitoring magnetic field change through a Hall effect sensor, detecting temperature abnormity in combination with a temperature sensor, carrying out real-time data processing by utilizing an embedded MCU, and automatically entering a calibration mode before charging each time; the method comprises the following steps: acquiring stable magnetic field distribution as a reference value, tracking magnetic field change by using a self-adaptive filter, continuously monitoring magnetic field intensity change in a charging process, comparing the magnetic field intensity change with the reference value, judging whether the magnetic field intensity change exceeds a normal range or not by setting a threshold value, immediately cutting off a power supply and giving an alarm to a user if foreign matters are detected, and after the user confirms that the foreign matters are removed, stopping charging. According to the method, the foreign matters can be accurately detected in different environments through dynamic threshold adjustment and feature optimization, so that the safety of wireless charging and the user experience are improved.

The invention provides a metal detection system and method with a partition detection function. The metal detection system comprises a conveying device which is provided with a conveying frame and a conveying belt arranged on the conveying frame; the metal detector comprises a shell located on the conveying frame and a detector arranged in the shell, the detector is provided with a transmitting assembly and a receiving assembly, in the width direction of the conveying belt, the transmitting assembly forms an annular transmitting area, and the receiving assembly forms an independent detection area and a composite detection area corresponding to the annular transmitting area; wherein in response to the movement of the conveyor belt, the detector is used for determining the positions of the metal foreign matters passing through the annular emission area, the independent detection area and the composite detection area in the materials on the conveyor belt. According to the invention, the position of the metal foreign matter in the material is rapidly and accurately positioned, the accuracy and reliability of detection are improved, and the subsequent targeted treatment on the material containing the metal foreign matter is facilitated.

The invention discloses an intelligent iron removal monitoring management method and system for a conveying belt and a storage medium, and the method comprises the steps: obtaining ferromagnetic target information, generating a foreign matter monitoring report according to the ferromagnetic target information, and finally carrying out the iron removal operation according to the foreign matter monitoring report and the state information of an iron removal unit. According to the device, metal foreign matters of different types and positions are sucked and removed, an operation instruction can be sent out in time before the foreign matters reach an iron removal area, timely and accurate actuation of the iron removal unit is ensured, the iron removal efficiency and accuracy of the conveying belt are remarkably improved, the impact risk on coal flow of the conveying belt is reduced, and the service life of the conveying belt is prolonged. And the automation level and the real-time monitoring capability of the system are improved.

The invention provides a method for identifying the characteristics of a metal foreign body in a GIS, and the method comprises the steps: building an electric field simulation model, and setting the metal foreign body; a multi-modal sensor is adopted to collect signals generated by partial discharge of the metal foreign matter so as to obtain a multi-modal atlas database; performing multi-domain feature extraction on the multi-modal atlas database, and generating a lightweight fingerprint feature vector through feature dimension reduction; the lightweight fingerprint feature vector sequentially passes through all steps of a combinatorial algorithm to solve identification items of the metal foreign matter; and selecting a globally optimal group of identification items to be combined into a metal foreign matter feature identification scheme. According to the invention, fine analysis and processing are carried out on partial discharge signals through a signal processing and pattern recognition algorithm, so that the detection and classification precision of metal foreign matters can be effectively improved; real-time monitoring and quick response under complex working conditions can be realized, a quantitative basis can be provided for fault early warning and equipment maintenance, and the operation reliability and safety of GIS equipment are further enhanced.

The invention provides a bag breaking cutter and automatic unpacking equipment. The bag breaking cutter comprises a supporting shaft, a supporting piece, a blade clamping base, a plurality of blades and a cutter tip. The supporting piece is fixedly connected to the supporting shaft. The blade clamping seats and the supporting pieces are arranged at intervals in the axial direction of the supporting shaft. One end of each blade is connected with the supporting piece, the other end of each blade is connected with the blade clamping base, and the multiple blades are arranged at intervals in the circumferential direction of the supporting shaft. The tool noses are fixed to the blade clamping base, the tool noses and the blades are arranged in the axial direction of the supporting shaft, and the blades are clamped between the blade clamping base and the tool noses. The blade is connected and supported through the supporting piece and the blade clamping base, the blade is fixed through the supporting piece, the blade clamping base and the tool nose together, and therefore the blade is fixed relative to the supporting shaft, bolt-free fixing of the blade is achieved, and the problem that bolts are prone to loosening when the bag breaking tool works for a long time is solved; the risk that metal foreign matter is introduced into materials is reduced, and the disassembly and assembly difficulty of the blade is reduced.

The invention relates to the technical field of magnetic coupling wireless power transmission, and particularly discloses a multi-parameter WPT system metal foreign matter detection method and system based on a neural network, and the method can uniquely determine the one-to-one relationship of different working states of a WPT system based on different combinations of M identification parameters. A neural network model and a data set are constructed according to the M identification parameters corresponding to the N working states, the neural network model is trained and tested through the constructed data set, the obtained neural network model can output the corresponding working state for any group of M identification parameters, and therefore whether the metal foreign matter exists or not is determined. According to the method, multiple parameters of the WPT system are fused, the neural network model is used for researching metal foreign matter detection under different working conditions of the system, the change of the working conditions can be judged, and the metal foreign matter with a certain size can be recognized at a certain position.

The utility model discloses an automatic separating device for metal foreign matters in tobacco shreds, which comprises a base, the top of the base is fixedly connected with a shell, the top of the inner wall of the shell is fixedly connected with a mounting rack, the bottom of the mounting rack is fixedly connected with a metal detector, the top of the shell is fixedly connected with a hydraulic cylinder, and the hydraulic cylinder is fixedly connected with a hydraulic cylinder. And the bottom of the hydraulic cylinder is fixedly connected with an electromagnet. The utility model relates to the technical field of tobacco production, in particular to an automatic separating device for metal foreign matters in tobacco shreds, which realizes the control of the thickness of the tobacco shreds on a conveying component through the matching among a first motor, a double-thread screw, a threaded block, a sliding rod, an inclined column, a transverse column and a vertical plate. The problem that when an existing automatic separation device automatically separates metal foreign matter in tobacco shreds, due to the fact that the tobacco shreds on conveying equipment are thick, some metal hidden in the middles of the tobacco shreds cannot be easily found by a metal detector, the situation of missing occurs, and the separation effect of the existing automatic separation device is reduced is solved.

The invention relates to the technical field of metal foreign matter detection, in particular to a metal foreign matter detection method, metal foreign matter detection equipment and a storage medium, and the method comprises the steps: obtaining the detection statistics of a to-be-detected product; according to the detection statistical magnitude, on the basis of a preset point taking rule, calculating to obtain average noise power; according to the average noise power, a detection threshold value is obtained through calculation; and judging whether the detection statistical magnitude is greater than the detection threshold value, if so, determining that the detection result contains the metal foreign matters, and otherwise, determining that the detection result does not contain the metal foreign matters. The method has the advantages that the precision and accuracy of metal foreign matter detection are improved, and meanwhile the detection rate and the false alarm rate can be taken into account under the condition of the low signal-to-noise ratio.

The invention belongs to the technical field of lithium batteries, and discloses a method for detecting metal foreign matters in slurry, which comprises the following specific steps: diluting positive or negative slurry by using a corresponding solvent, selecting a filter membrane with a proper pore size for first suction filtration, cleaning the filter membrane by using the solvent after the first suction filtration is finished, then performing second suction filtration on the cleaning solution, and leaving the filter membrane to be detected after the second suction filtration is finished; flatly laying a clean color developing filter membrane on a white background plate, dropwise adding an acid solution and an oxidizing solution in sequence, laying the filter membrane to be detected on the surface of the color developing filter membrane and infiltrating, dropwise adding a color developing agent after about 1 minute, indicating that the metal foreign matters exist if colored points appear on the surface of the filter membrane, and indicating that the number of the points is in positive correlation with the content of the metal foreign matters; and whether the slurry is qualified can be preliminarily judged according to the quantity. The method disclosed by the invention is simple to operate, less in time consumption and low in cost, can be used for detecting the slurry of the production line every shift, can quickly find abnormal samples and timely treat the abnormal samples, and improves the production efficiency and the production stability.

The utility model relates to the field of wet tissue processing, in particular to a metal foreign matter detection device which comprises a workbench, table legs, a conveying mechanism and a detection classification mechanism. The conveying mechanism is arranged on the outer side of the workbench and used for fixing wet tissues and conveying the wet tissues to a detection point; the detecting and classifying mechanism is arranged on the top of the workbench and used for detecting the content of metal foreign matter of the wet tissue at a fixed point and separating qualified products from defective products. Through the arrangement of the conveying mechanism, wet tissues are conveyed and detected at fixed points, continuous and rapid metal impurity detection can be realized, manual intervention is reduced, the production efficiency is improved, meanwhile, the consistency of a detection environment can be ensured, and the influence of factors such as position change or vibration on a detection result is reduced, so that the detection accuracy is improved, and the detection efficiency is improved. And the wet tissues can pass through the metal detector one by one, so that missing detection is effectively avoided, and each wet tissue is ensured to be fully detected.

The invention discloses a reference frequency calibration and foreign matter detection method for a wireless charging system. The method comprises the following steps: firstly, acquiring coil initialization resonant frequency and recording a reference input current value in a no-load state of a transmitting end; then dynamically adjusting the reference resonant frequency through a pre-established compensation model based on the environment temperature and the input voltage; detecting the offset between the adjusted reference frequency and the actual resonant frequency and the input current offset in real time, and comparing the offset with a preset threshold value to judge the metal foreign matter; and for the condition that the frequency deviation is in the preset verification interval, the transmitting end and the receiving end complete communication protocol handshake and then are switched to the resonant working frequency, and charging is started, so that accurate calibration of the idle standby frequency and efficient identification of the foreign matter are realized.

The invention relates to a GIS (Geographic Information System) metal foreign matter identification method and device based on a photon-phase technology. The photon counting detection system comprises a photon counting platform, a partial discharge sensor, a partial discharge-free alternating current excitation source, a data acquisition piece connected with the photon counting platform and the partial discharge sensor, and a data processing piece connected with the data acquisition piece which are sequentially connected in parallel. The method comprises the following steps: acquiring photon pulse data of the current metal foreign matter by using the photon counting detection system; performing phase analysis on the photon pulse data of the current metal foreign body to obtain a photon counting phase analysis spectrogram of the current metal foreign body; and extracting characteristic parameters of the current metal foreign matter based on the photon counting phase analysis spectrogram, and inputting the characteristic parameters of the current metal foreign matter into a pre-trained metal foreign matter identification model to obtain the type of the current metal foreign matter. Therefore, the problem that related technologies are greatly influenced by the environment is solved, and accurate recognition of unknown metal foreign bodies is achieved.

The invention discloses a wireless charging circuit for detecting foreign matters. The wireless charging circuit comprises a transmitting end and a receiving end. The transmitting end generates an alternating magnetic field through a high-frequency full-bridge inversion module, and performs coded modulation based on a unique preset device number. The receiving end senses the magnetic field through coupling and samples and decodes the magnetic field to realize three-stage verification with the transmitting end, and the three-stage verification comprises wireless communication verification, encryption key verification and equipment identity verification. The control module determines whether to start charging or output a metal foreign matter alarm signal according to the verification result. According to the scheme, the hierarchical safety verification process is completed before charging, so that the safety of wireless energy transmission and the accurate recognition capability of the system on the foreign matter are ensured, the stability and reliability of the wireless charging system are improved, the abnormal problem of fire catching caused by heating of the foreign matter in the charging process is avoided, and the charging safety is improved. Meanwhile, the method is suitable for wireless power supply application scenes supporting a security authentication mechanism.

The application discloses a general surgery operation trauma nursing device and belongs to the technical field of medical devices, which comprises a body, and a separation component is arranged on the inside and outside of an operating table, wherein the separation component comprises a collecting frame which is inserted into the operating table, a scraping ring is fixedly connected to the inside of the collecting frame, a protective cover is arranged in the operating table, and a driving motor is arranged in the protective cover. The magnetic block ring is arranged to adsorb metal foreign matters, and the rotating disc accelerates the flow of liquid after rotation, so that the foreign matters and necrotic tissues are quickly separated. Since the magnet ring can adsorb the metal foreign matters during rotation, the foreign matters and necrotic tissues are separated, the foreign matters carrying the necrotic tissues are prevented from sinking into the physiological saline and being difficult to separate, and the rotating disc only accelerates the flow speed of the physiological saline during stirring of the physiological saline, so that the over-dissolution of the necrotic tissues is reduced, and the separation effect of the foreign matters and the necrotic tissues is guaranteed.

The present application belongs to the field of clothes processing equipment, and specifically discloses a clothes processing equipment metal foreign matter detection method, device and storage medium. The method comprises the following steps: in the process of putting clothes into the clothes processing equipment, firstly, collecting the real-time geomagnetic field intensity data set of the clothes processing equipment through the geomagnetic sensor; then, obtaining the denoised geomagnetic field intensity data set by denoising the real-time geomagnetic field intensity data set; secondly, establishing a denoised position fingerprint map according to the denoised geomagnetic field intensity data set; finally, inputting the denoised position fingerprint map into a preset field intensity time sequence classification model to obtain the detection result of whether there is metal foreign matter in the clothes. The method provided by the present application can reduce energy consumption, is not limited by the time range, can improve the accuracy of metal foreign matter classification detection, effectively improve the accuracy of metal foreign matter detection, reduce the complexity of detection, and improve the user experience.

The technical problem of the present invention is to provide a magnetic detection system capable of detecting metal foreign matters with high sensitivity. As a technical means for solving the technical problem, a magnetism detection system (100) is provided with: a signal generation circuit (501) that generates an excitation signal (P); an excitation coil (250) to which an excitation signal (P) is supplied; a buffer circuit (503) connected between the signal generation circuit (501) and the excitation coil (250); magnetic sensors (40A, 40B) that are disposed on opposite sides of each other in the coil axis direction when viewed from the excitation coil (250); a sample stage (300) that holds a sample (310) between the excitation coil (250) and the magnetic sensor (40A); and a detection circuit that generates a detection signal (OUT) on the basis of the difference between the output signals (Pa, Pb) output from the magnetic sensors (40A, 40B). As a result, it is possible to suppress a disorder in the waveform of the excitation signal (P) by means of the snubber circuit (503), and thus it is possible to detect a metal foreign object with high sensitivity.

The utility model discloses a system for removing metal foreign matters in an electrode material. The system for removing the metal foreign matter in the electrode material comprises a machine frame, a conveying belt, a hopper and a microwave processing box, the conveying belt, the hopper and the microwave processing box are all arranged on the machine frame, the hopper is arranged at the input end of the conveying belt, and the microwave processing box is arranged in the middle of the conveying belt. According to the characteristic that the metal foreign matter can selectively absorb microwaves with certain wavelengths, the metal foreign matter in the electrode material is removed through the microwaves, the method is higher in efficiency, and the metal foreign matter can be removed more thoroughly.

The invention belongs to the technical field of battery performance detection, and particularly discloses a method for detecting metal foreign matters in a pole piece and evaluating the quality of the pole piece, and the method for detecting the metal foreign matters in the pole piece comprises the following steps: (1) mixing a to-be-detected pole piece with a first solvent, and carrying out first ultrasonic treatment on the obtained first mixture, enabling the dressing on the to-be-detected pole piece to fall off to obtain a current collector and first turbid liquid containing the dressing; (2) carrying out adsorption treatment on the first turbid liquid by utilizing a permanent magnet, and collecting an adsorption product adsorbed on the permanent magnet to obtain metal foreign matters; and (3) detecting the metal foreign matters by using a cleanliness instrument to obtain metal foreign matter detection information. The method can detect foreign matters on the surface of the pole piece and in the dressing, the detection range is wider, and the quality of the pole piece can be evaluated more accurately.

The application relates to the technical field of textile detection, and discloses an automatic detection and rejection device for textiles, which comprises a base, a transmission device for transmitting the textile to be detected, a first detection mechanism for detecting metal foreign matters in the textile to be detected, a second detection mechanism for detecting non-metal foreign matters in the textile to be detected, a cleaning mechanism for cleaning the transmission belt, a rejection mechanism arranged at the rear end of the first detection mechanism and the second detection mechanism respectively and used for rejecting the textile containing foreign matters, and a slide way installed at the rear end of the first detection mechanism and the second detection mechanism and used for conveying the textile containing foreign matters. The textile to be detected is conveyed to the first detection mechanism and the second detection mechanism by the transmission device, metal foreign matters and non-metal foreign matters in the textile can be separated and detected at the same time, and the detection accuracy is greatly improved.

The application relates to the field of battery detection. The application can effectively detect metal foreign matters in battery materials. The application discloses a metal foreign matter detection method, device, electronic device and storage medium for battery materials. The metal foreign matter detection method comprises the following steps: performing X-ray imaging on the battery material to obtain a material image; processing the material image to obtain a metal foreign matter image; and counting target metal foreign matters in the metal foreign matter image to obtain the number of the target metal foreign matters. In the metal foreign matter detection method, the battery material is subjected to X-ray imaging to obtain a material image, and the material image is processed to obtain a metal foreign matter image, so that the number of target metal foreign matters can be effectively detected.

This utility model relates to the field of extrusion device technology, specifically to a precise temperature-controlled thermoplastic elastomer production extrusion device, including an extruder body with a feed inlet and a discharge channel. An outer cover is fixedly connected to the discharge channel. The outer cover contains a screening component for screening for metal foreign objects in the material. The screening component includes a receiving box located inside the outer cover, with a movable frame slidably connected to the receiving box. This utility model uses the screening component to allow material from the feed hopper to enter the receiving box. A motor-driven metal detector then screens and checks the material in the receiving box for metal foreign objects. If no foreign objects are found, a cam divider rotates the receiving box, discharging the material into the extruder body. If foreign objects are found, a drive component pushes the outer cover, separating the discharge channel from the feed inlet, thus facilitating the discharge of material containing foreign objects.

The utility model provides a kind of feed additive metal foreign matter multistage detection device, including rack, and be provided with feeding mechanism, level material mechanism and detection mechanism on rack, and feeding mechanism is used to transport feed additive;Level material mechanism includes level material belt, two level material rollers and driving part;Two level material rollers are respectively along transverse rotation to set on rack;Level material belt is set to two level material rollers outside, and is placed in the above of feeding mechanism.Utilize level material belt that feeding mechanism import is provided, and level material belt rotation setting, the material that enters the import of feeding mechanism is flattened, and the larger metal foreign matter that enters therein is preliminarily screened, and is blocked in import outside, so that it does not enter into feeding mechanism.Level material belt forms stable flat conveying, avoids feed stacking, solves the problem that feed additive is prone to stacking in conveying process, reaches the effect that feed additive is flatly conveyed, provides stable material state for subsequent detection.

The utility model discloses a material conveying device for detecting and removing metal foreign matters, which comprises a support, supporting legs are arranged on two sides of the support, a conveying belt is arranged in the support, the material conveying device for detecting and removing the metal foreign matters further comprises a screening device, a material conveying device, a material conveying device and a material conveying device, the turning device is arranged above the bracket; the cleaning device is arranged above the bracket; wherein the screening device can be used for screening and removing metal foreign matters in materials. The utility model relates to the technical field of metal recovery, in particular to a material conveying device for detecting and removing metal foreign matters, which can clean the removed metal foreign matters while screening through the matching of a bracket, a screening device, a conveying belt and a cleaning device, so that the metal foreign matters do not need to be carried to a specific position to be cleaned by a worker, and the working efficiency is improved. Therefore, the working intensity of workers can be greatly reduced.

The present application discloses a kind of clothes processing equipment and metal foreign matter detection method, the clothes processing equipment includes the metal detection module and infrared induction module being arranged at clothes delivery port;The metal foreign matter detection method includes: if it is judged that the interval time of the trigger signal generated by infrared induction module and the signal sensed by metal detection module exceeds the set interval time, it can be inferred that the user performs the clothes taking action, and the alarm device is not controlled to work.The above-mentioned metal foreign matter detection method provided by the present application can accurately distinguish and judge whether the user is throwing clothes or taking clothes.When it is judged that the interval time of the trigger signal generated by infrared induction module and the signal sensed by metal detection module exceeds the set interval time, it is inferred that the user is performing the clothes taking action, and the alarm device is not controlled to work, to avoid false alarm when taking clothes to bring the user's distress, improve the user's experience.

The utility model relates to foreign matter detection equipment for dried longan production, which comprises a frame and a first conveyor belt mounted on the frame, a push plate and a slide plate are respectively arranged on two opposite sides of the first conveyor belt, a metal detector positioned right above the first conveyor belt is arranged between the push plate and the slide plate, a second conveyor belt is arranged below the slide plate, and the second conveyor belt is arranged below the slide plate. A plurality of collecting boxes distributed at equal intervals are placed on the second conveying belt, one collecting box is located under the end, away from the first conveying belt, of the sliding plate, a driving unit used for driving the push plate to move in the direction close to or away from the sliding plate is arranged on the rack, and a controller is arranged in the rack. The first conveying belt, the second conveying belt, the metal detector and the driving unit are all electrically connected with the controller; when the metal detector detects that dried longans on the first conveyor belt contain metal foreign matters, the push plate pushes the dried longans containing the metal foreign matters into the collection box, so that the stop time of the first conveyor belt is shortened, and the metal detection efficiency is further improved.

The invention discloses a sealing-tape machine metal foreign matter positioning and marking system and a sealing-tape machine metal foreign matter positioning and marking method, and relates to the technical field of foreign matter detection.The sealing-tape machine metal foreign matter positioning and marking system comprises a metal detector, a positioning system controller, a position detecting device and a position indicating device; the position detection device comprises a fixing device, a steering engine and an elastic connecting rod, one end of the elastic connecting rod is hinged to the fixing device, the steering engine is located on the side, away from the fixing device, of the elastic connecting rod, and a distance measuring roller is rotationally installed at the other end of the elastic connecting rod. An acceleration sensor is further installed on the side, away from the photoelectric encoder, of the elastic connecting rod. Therefore, under normal work, the position detection device keeps a certain safe distance from the adhesive tape and does not make contact with the adhesive tape, and the service life of the position detection device is prolonged.

To provide a magnetic foreign metal substance removal device that is safe and has no unnecessary labor because it can check a monitor in a safe remote location and automatically check the adsorption status of magnetic foreign metal substances using AI, and also can remove magnetic foreign metal substances mechanically, making it very convenient and safe. [Solution] A magnetic metal foreign matter removal device for removing magnetic metal foreign matter used in a pipeline through which granular material passes comprises at least a magnet for attracting the magnetic metal foreign matter, a camera for capturing the state of the magnet, image data captured by the camera, and AI for analyzing the image data, and is characterized in that the AI ​​is trained to learn the image data in advance and determines whether or not the magnetic metal foreign matter has been attracted.

This invention provides a technology that efficiently suppresses the generation of metallic foreign matter when fixing screws to a metal plate. [Solution] The metal chassis 300 has a first surface 310, a second surface 312 facing the opposite side of the first surface 310, and a first through-hole 330 that penetrates between the first surface 310 and the second surface 312. The rear resin cover 500 has a third surface 510 facing the second surface 312, a cylindrical projection 520 that protrudes from the third surface 510 and is inserted into the first through-hole 330, a fourth surface 512 facing the opposite side of the third surface 510, and a second through-hole 530 that penetrates between the tip 522 of the cylindrical projection 520 and the fourth surface 512. The screw 600 has a shaft portion 610 that is inserted into the second through-hole 530, and a head portion 612 that is connected to the shaft portion 610 and is positioned on the fourth surface 512 without being inserted into the second through-hole 530.

The invention relates to a method for detecting metal impurities in an electrode active material, and the method comprises the following steps: 1, dissolving the electrode active material in a nitric acid aqueous solution to form a metal impurity extraction solution; a second step of plating the metal impurities from the metal impurity extraction solution onto an electrode; and a third step of measuring the content of metal impurities plated on the electrode.