Diaphragm detection method and device

Abstract

This application relates to a diaphragm detection method and device that can detect magnetic field signals on or within the diaphragm, perform feature extraction and analysis on the magnetic field signals, and obtain magnetic field state parameter information of the diaphragm. This information is then combined with the magnetic field state parameter information to accurately determine the presence of magnetic metal particles in the diaphragm. This solution, through magnetic field signal recognition and analysis, can accurately identify the presence of magnetic metal particles in the diaphragm, thereby improving diaphragm quality, reducing the possibility that diaphragm portions containing magnetic metal particles will flow into subsequent processes, and significantly improving battery quality.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a diaphragm detection method and device. Background Art

[0002] With the development of new energy technologies, secondary batteries, represented by lithium batteries, are gradually being applied to various fields, including energy storage systems, electric vehicles, and aerospace, bringing great convenience to people's daily production and life. As a key component within the battery, the separator plays a vital role in battery performance and safety. During the production and processing process, magnetic metal particles can easily form on the separator due to wear and tear of production equipment, metal dust in the workshop, and contamination of raw materials.

[0003] However, in the related art, it is difficult to detect magnetic metal particles using the membrane appearance inspection method. Summary of the Invention

[0004] Based on this, it is necessary to propose a diaphragm detection method and device to detect the magnetic metal particles in the diaphragm to improve the quality of the diaphragm.

[0005] The present application provides a diaphragm detection method, including: obtaining a magnetic field signal of the diaphragm; performing feature extraction and analysis based on the magnetic field signal to determine the magnetic field state parameter information of the diaphragm; the magnetic field state parameter information is used to characterize the magnetic field distribution state of the diaphragm; and determining the detection results of the magnetic metal particles of the diaphragm based on the magnetic field state parameter information.

[0006] The above-mentioned diaphragm inspection method detects magnetic field signals on or within the diaphragm, extracts and analyzes these signals to obtain the diaphragm's magnetic field state parameter information, and then combines this magnetic field state parameter information to accurately determine the presence of magnetic metal particles in the diaphragm. This solution, through magnetic field signal recognition and analysis, can accurately identify the presence of magnetic metal particles in the diaphragm, thereby improving diaphragm quality and reducing the possibility of diaphragm containing magnetic metal particles being transferred to subsequent processes, significantly enhancing battery quality.

[0007] In some embodiments, performing feature extraction and analysis based on the magnetic field signal to determine the magnetic field state parameter information of the diaphragm includes: performing filtering processing based on the magnetic field signal to obtain a preprocessed magnetic field signal; performing feature extraction and analysis based on the preprocessed magnetic field signal to determine the magnetic field state parameter information of the diaphragm.

[0008] After obtaining the magnetic field signal, the above scheme will filter the magnetic field signal and then perform feature extraction and analysis, effectively reducing the impact of environmental noise on detection and effectively improving detection accuracy.

[0009] In some embodiments, the feature extraction and analysis performed based on the preprocessed magnetic field signal to determine the magnetic field state parameter information of the diaphragm includes: performing background magnetic field correction based on the preprocessed magnetic field signal to obtain a corrected magnetic field signal; and performing feature extraction and analysis based on the corrected magnetic field signal to determine the magnetic field state parameter information of the diaphragm.

[0010] In the above scheme, after filtering the magnetic field signal, the pre-processed magnetic field signal is further corrected for the background magnetic field, thereby reducing the impact of the background magnetic field on the detection accuracy and further improving the detection accuracy.

[0011] In some embodiments, the magnetic field state parameter information includes a magnetic field intensity peak value; the detection result of the magnetic metal particles of the diaphragm is determined based on the magnetic field state parameter information, including: when the magnetic field intensity peak value is greater than or equal to a preset peak value threshold value, determining that magnetic metal particles exist in the diaphragm; when the magnetic field intensity peak value is less than the preset peak value threshold value, determining that magnetic metal particles do not exist in the diaphragm.

[0012] The above solution uses the magnitude of the peak value of the magnetic field intensity in the magnetic field signal to analyze and determine whether magnetic metal particles exist in the diaphragm, and has a high judgment accuracy.

[0013] In some embodiments, the magnetic field state parameter information also includes a peak pulse width, and determining the detection result of the magnetic metal particles of the diaphragm based on the magnetic field state parameter information includes: determining the size of the magnetic metal particles based on the peak pulse width and the tape running speed of the diaphragm.

[0014] The above scheme can also realize magnetic metal particle size analysis in combination with the peak pulse width of the magnetic field intensity peak value in the presence of magnetic metal particles, thereby identifying the size of the magnetic metal particles and having high accuracy in magnetic metal particle size analysis.

[0015] In some embodiments, the magnetic field state parameter information further includes a magnetic field energy value, and determining the detection result of the magnetic metal particles of the diaphragm based on the magnetic field state parameter information includes: determining the type of magnetic metal particles based on the magnetic field energy value.

[0016] The above solution can also determine the type of magnetic metal particles in the presence of magnetic metal particles by combining the magnetic field energy value within a preset frequency band, thereby meeting the needs of magnetic metal particle type identification scenarios and improving the reliability of diaphragm detection.

[0017] In some embodiments, determining the type of magnetic metal particles based on the magnetic field energy value includes: determining the type of magnetic metal particles by matching the magnetic field energy value with a preset identification relationship; the preset identification relationship stores the magnetic metal particle types corresponding to different magnetic field energy values.

[0018] The above solution determines the type of magnetic metal particles by matching the magnetic field energy value with the preset identification relationship, and has a high efficiency in identifying the type of magnetic metal particles.

[0019] In some embodiments, determining the type of magnetic metal particles based on the magnetic field energy value includes: performing inference analysis based on the magnetic field energy value and a preset recognition model to determine the type of magnetic metal particles; the preset recognition model is obtained by model training through the magnetic field signal of the actual production line.

[0020] The above solution determines the type of magnetic metal particles by combining the magnetic field energy value and the preset recognition model for inference analysis, and has a high accuracy in identifying the type of magnetic metal particles.

[0021] In some embodiments, the magnetic field state parameter information also includes the trigger time of the magnetic field intensity peak, and the detection results of the magnetic metal particles of the diaphragm are determined based on the magnetic field state parameter information, including: determining the position of the magnetic metal particles based on the trigger time and the tape speed of the diaphragm.

[0022] The above solution, in the presence of magnetic metal particles, can also combine the triggering time of the magnetic field intensity peak to analyze the position of the magnetic metal particles, thereby locating the diaphragm where the magnetic metal particles exist, with high position recognition accuracy.

[0023] In some embodiments, the method further includes: dynamically adjusting the sampling frequency of the magnetic field signal according to the feedback of the tape running speed of the diaphragm.

[0024] The above solution can also be combined with the real-time feedback of the diaphragm's tape speed to adjust the sampling frequency of the magnetic field signal, so that the magnetic field can be detected at all positions in the diaphragm's tape direction, further improving the accuracy of diaphragm detection.

[0025] In some embodiments, acquiring the magnetic field signal of the diaphragm includes performing a differential operation based on magnetic field acquisition signals at adjacent positions to determine the magnetic field signal of the diaphragm.

[0026] The above solution uses the magnetic field acquisition signals at adjacent positions as a differential pair and eliminates the interference of the environmental magnetic field by differential signal processing, thereby further improving the accuracy of diaphragm detection.

[0027] In some embodiments, the method further includes: outputting an exception handling instruction when the detection result indicates that magnetic metal particles exist in the diaphragm; the exception handling instruction is used to instruct to perform exception handling on the diaphragm where magnetic metal particles exist, and the exception handling includes at least one of alarm, marking and rejection.

[0028] In the above scheme, when magnetic metal particles are present, the diaphragm containing magnetic metal particles can be abnormally handled by at least one of marking, alarming and rejecting, which greatly reduces the possibility of this part of the diaphragm flowing into subsequent processes and effectively improves the battery quality.

[0029] The present application provides a diaphragm detection device, comprising a processor and at least one magnetic detector, wherein the magnetic detector is used to collect the magnetic field signal of the diaphragm; the processor is connected to the magnetic detector, and the processor is used to execute the steps of the above-mentioned diaphragm detection method.

[0030] The diaphragm detection device described above can detect magnetic field signals on or within the diaphragm, extract and analyze the magnetic field signals to obtain the diaphragm's magnetic field state parameter information, and then combine this magnetic field state parameter information to accurately determine the presence of magnetic metal particles in the diaphragm. This solution, through magnetic field signal recognition and analysis, can accurately identify the presence of magnetic metal particles in the diaphragm, thereby improving diaphragm quality and reducing the possibility of diaphragm containing magnetic metal particles being transferred to subsequent processes, significantly enhancing battery quality.

[0031] In some embodiments, there are multiple magnetic detectors, and the multiple magnetic detectors are arranged along the width direction of the diaphragm; the width direction is perpendicular to the running direction of the diaphragm.

[0032] In the above scheme, a plurality of magnetic detectors are configured in the diaphragm detection device and are arranged along the width direction perpendicular to the diaphragm running direction. In this way, it is only necessary to fix the magnetic detectors and detect each position of the diaphragm through the running of the diaphragm, which has high detection accuracy.

[0033] In some embodiments, the plurality of magnetic detectors are arranged in a magnetic sensing array along the width direction of the diaphragm.

[0034] The above solution arranges multiple magnetic detectors in a row along the width direction of the diaphragm, thereby realizing detection of different positions of the diaphragm, and can also effectively reduce the number of magnetic detectors and save hardware costs.

[0035] In some embodiments, a plurality of the magnetic detectors are arranged into multiple columns of magnetic sensing arrays along the width direction of the diaphragm, and the projection of the magnetic detectors in any column of the magnetic sensing array in the tape running direction is located between two magnetic detectors in adjacent magnetic sensing arrays.

[0036] In the above solution, the magnetic detectors are arranged into multiple columns along the width direction of the diaphragm, and the magnetic detectors in each column are staggered, so that any position in the width direction of the diaphragm can effectively detect the magnetic field signal, reducing the possibility of missed detection.

[0037] In some embodiments, the diaphragm detection device further includes a magnetic shielding assembly, and the magnetic detector is disposed inside the magnetic shielding assembly.

[0038] In the above solution, the magnetic detector is arranged inside the magnetic shielding assembly, which can effectively reduce the interference of the external environment on the magnetic detector and improve the accuracy of collecting magnetic field signals.

[0039] In some embodiments, the diaphragm detection device further includes a magnetic field enhancement component, which is spaced apart from the diaphragm and configured to apply a magnetic field to a collection area of ​​the magnetic detector.

[0040] The above solution applies a magnetic field to the collection area of ​​the magnetic detector through the magnetic field enhancement component, thereby enhancing the magnetic field in the collection area, that is, enhancing the magnetism of the magnetic metal particles, thereby effectively improving the collection reliability of the magnetic field signal.

[0041] In some embodiments, the apparatus further comprises an exception handling component, wherein the exception handling component is configured to respond to an exception handling instruction sent by the processor to perform exception handling on the diaphragm having the magnetic metal particle portion.

[0042] In the above scheme, when magnetic metal particles are present, the diaphragm containing magnetic metal particles can be abnormally handled by at least one of marking, alarming and rejecting, which greatly reduces the possibility of this part of the diaphragm flowing into subsequent processes and effectively improves the battery quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0044] Figure 1 This is a schematic structural diagram of a diaphragm detection device in some embodiments of the present application;

[0045] Figure 2 This is a flow chart of a diaphragm detection method in some embodiments of the present application;

[0046] Figure 3 This is a flow chart of a diaphragm detection method in some other embodiments of the present application;

[0047] Figure 4 This is a flow chart of a diaphragm detection method in some embodiments of the present application;

[0048] Figure 5 This is a flow chart of a diaphragm detection method in some further embodiments of the present application;

[0049] Figure 6 Schematic diagram of the waveform of the magnetic field signal in some embodiments of the present application;

[0050] Figure 7 This is a flow chart of a diaphragm detection method in some other embodiments of the present application;

[0051] Figure 8 This is a flow chart of a diaphragm detection method in some embodiments of the present application;

[0052] Figure 9 This is a flow chart of a diaphragm detection method in some further embodiments of the present application;

[0053] Figure 10 This is a flow chart of a diaphragm detection method in some other embodiments of the present application;

[0054] Figure 11 This is a schematic diagram of the configuration of the magnetic detector in some embodiments of the present application;

[0055] Figure 12 Schematic diagram of the structure of the diaphragm detection device in other embodiments of the present application;

[0056] Figure 13 This is a schematic structural diagram of a diaphragm detection device in some other embodiments of the present application;

[0057] Figure 14 This is a schematic structural diagram of a diaphragm detection device in some further embodiments of the present application.

[0058] Description of reference numerals:

[0059] 10-magnetic detector, 20-processor, 30-abnormal processing component, 100-diaphragm, 40-magnetic shielding component, 50-magnetic field enhancement component. DETAILED DESCRIPTION

[0060] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0062] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0063] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0064] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0065] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0066] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0067] Currently, market developments indicate that batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in a variety of fields such as aerospace. As battery applications continue to expand, market demand is also growing.

[0068] As a critical battery component, the quality of the diaphragm directly impacts battery quality. Research has found that during the diaphragm production process, magnetic metal particles can easily form on the diaphragm due to wear and tear on production equipment, metal dust in the workshop, and contamination from raw materials. If these magnetic metal particles are not treated, they can flow into the diaphragm during subsequent processing, affecting overall battery performance and, in severe cases, even causing thermal runaway.

[0069] In related technologies, diaphragm production lines generally use optical detection to detect the diaphragm's appearance, size, holes and other physical properties. These detection methods are not sensitive to magnetic metal particles and it is difficult to identify magnetic metal particles.

[0070] In-depth research has revealed that the magnetic metal particles present on the diaphragm are generally metal debris such as iron (Fe) and nickel (Ni). These magnetic metal particles exhibit spontaneous magnetization, and their internal electron spin and orbital motion also generate microscopic magnetic moments. These moments manifest macroscopically as permanent magnetism (such as ferromagnetism or ferrimagnetism), thus generating a magnetic field in the surrounding space. Therefore, it is possible to consider installing a magnetic field detector on the diaphragm to detect magnetic field distortion on or within the diaphragm to identify the presence of magnetic metal particles.

[0071] Based on the above considerations, the present application provides a diaphragm detection method, which includes setting up at least one magnetic detector to collect the magnetic field signal of the diaphragm, and sending it to the processor for feature extraction and analysis to determine the magnetic field state parameter information of the diaphragm, thereby determining the detection results of the magnetic metal particles of the diaphragm based on the magnetic field state parameter information.

[0072] The above scheme can accurately identify the magnetic metal particles in the diaphragm by means of magnetic field signal recognition and analysis, thereby improving the quality of the diaphragm, reducing the possibility of the diaphragm containing magnetic metal particles flowing into subsequent processes, and greatly improving the quality of the battery.

[0073] The diaphragm detection method provided in the embodiment of the present application is used to perform magnetic metal detection on the diaphragm. It can be specifically applied after the diaphragm is prepared and before the diaphragm is rolled up for storage; it can also be applied before the diaphragm is cut to assemble the battery. The specific selection can be made based on actual needs and is not limited here.

[0074] See also Figure 1 , this application provides a diaphragm detection method by Figure 1 The diaphragm detection device shown is implemented, and the diaphragm detection device includes a processor 20 and at least one magnetic detector 10. The magnetic detector 10 is spaced apart from the diaphragm (that is, 100 in the figure), and the magnetic detector 10 is used to collect the magnetic field signal of the diaphragm; the processor 20 is connected to the magnetic detector 10, and the processor 20 is used to execute the steps of the diaphragm detection method according to the magnetic field signal.

[0075] See also Figure 2 The present application provides a diaphragm detection method, including step 202, step 204 and step 206.

[0076] Step 202: Acquire the magnetic field signal of the diaphragm.

[0077] Specifically, the magnetic field signal is collected by at least one magnetic detector spaced apart from the diaphragm, which is in communication with the processor. For magnetic metal particles (such as iron, nickel, and cobalt), due to their ferromagnetic properties, a micromagnetic-based magnetic detector can detect magnetic anomalies caused by their ferromagnetism. According to the corresponding model algorithm, the magnetic field intensity B is inversely proportional to the cube of the detection distance r and directly proportional to the mass m of the magnetic metal particle. The formula is B = XmH / ρr 3 Where X is the magnetic permeability, a constant, m represents the mass of the magnetic metal particle, H represents the external magnetic field strength, ρ represents the material density of the magnetic metal particle, and r represents the distance from the magnetic detector to the magnetic metal particle. Based on this principle, magnetic metal particles will have a certain magnetic field, so magnetic metal particle detection can be achieved by collecting and analyzing the magnetic field signal of the diaphragm.

[0078] The magnetic field signal, which is a signal used to characterize the change in magnetic field strength across the diaphragm, is not limited to a single type. In one embodiment, the magnetic field signal may be a magnetic field strength value that gradually changes with sampling time. In other embodiments, the magnetic field strength may be represented by a voltage signal or an impedance value. Accordingly, the magnetic field signal may be a voltage value or an impedance value that gradually changes with sampling time, and the specific type of magnetic detector may vary. To facilitate understanding of the technical solution of the application, the following embodiments are explained using magnetic field strength values.

[0079] A magnetic detector is a device that can detect the magnetic field of magnetic metal particles. A processor is a device with certain data processing and storage capabilities. Processors are not limited to a single type and can include microcontroller units (MCUs) or central processing units (CPUs). There are no specific limitations.

[0080] There are many types of magnetic detectors. These can be electromagnetic induction-based magnetic detectors, such as Hall sensors and induction coil sensors, or magnetoresistive magnetic detectors, such as giant magneto-impedance (GMI) magnetic sensors. For ease of understanding the technical solution of this application, the following embodiments will all be understood to include GMI magnetic sensors.

[0081] The number of magnetic detectors is not unique and can be determined based on the actual size of the diaphragm, as long as the corresponding collection area of ​​one or more magnetic detectors covers the width of the diaphragm as much as possible. More specifically, full coverage can be achieved across the width of the diaphragm, allowing detection at any position along the width of the diaphragm during tape transport.

[0082] It should be pointed out that the processor of the diaphragm detection device can be an additional device configured in addition to the controller of the diaphragm production line, or it can directly adopt the controller of the diaphragm production line, and the specific selection can be made based on actual needs.

[0083] Step 204 : performing feature extraction and analysis based on the magnetic field signal to determine magnetic field state parameter information of the diaphragm.

[0084] Specifically, the magnetic field state parameter information is used to characterize the magnetic field state of the diaphragm. During the diaphragm's tape transport, the magnetic detector collects data in real time and sends the acquired magnetic field signals to a processor for feature extraction and analysis. This analysis can be performed in either the time domain or the frequency domain, depending on actual needs. Ultimately, the magnetic field state parameter information of the diaphragm is obtained.

[0085] Step 206: Determine the detection result of the magnetic metal particles of the diaphragm according to the magnetic field state parameter information.

[0086] Specifically, the detection results are information used to characterize the presence of magnetic metal particles in the diaphragm and / or the characteristic parameters of the magnetic metal particles in the diaphragm. After obtaining the magnetic field state parameter information, the processor will analyze and calculate it in conjunction with the magnetic field state parameter information to ultimately determine whether the diaphragm contains magnetic metal particles. Furthermore, in other embodiments, the characteristic parameters of the magnetic metal particles can also be determined in conjunction with the magnetic field state parameter information.

[0087] It should be noted that the characteristic parameters of the magnetic metal particles are not unique and may vary depending on the acquired magnetic field state parameter information. For example, in some embodiments, the characteristic parameters may include at least one of the position, size, and type of the magnetic metal particles.

[0088] The above-mentioned diaphragm inspection method detects magnetic field signals on or within the diaphragm, extracts and analyzes these signals to obtain the diaphragm's magnetic field state parameter information, and then combines this magnetic field state parameter information to accurately determine the presence of magnetic metal particles in the diaphragm. This solution, through magnetic field signal recognition and analysis, can accurately identify the presence of magnetic metal particles in the diaphragm, thereby improving diaphragm quality and reducing the possibility of diaphragm containing magnetic metal particles being transferred to subsequent processes, significantly enhancing battery quality.

[0089] See also Figure 3In some embodiments, step 204 includes step 302 and step 304 .

[0090] Step 302: Filter the magnetic field signal to obtain a pre-processed magnetic field signal.

[0091] Step 304 : performing feature extraction and analysis based on the pre-processed magnetic field signal to determine magnetic field state parameter information of the diaphragm.

[0092] Specifically, when the magnetic detector collects the magnetic field signal of the diaphragm, due to the presence of certain noise in the detection environment, in order to improve the detection accuracy, the magnetic field signal needs to be subjected to noise filtering.

[0093] It should be noted that there is not only one way to filter the magnetic field signal. In one embodiment, the filtering method includes at least one of hardware filtering and digital filtering. Hardware filtering uses an analog bandpass filter (0.1kHz (kilohertz)-10kHz) to suppress power frequency noise (50Hz (hertz) / 60Hz) and high-frequency electromagnetic interference; while digital filtering can eliminate specific frequency noise (such as the motor vibration frequency of the diaphragm production line, etc.).

[0094] After obtaining the magnetic field signal, the above scheme will filter the magnetic field signal and then perform feature extraction and analysis, effectively reducing the impact of environmental noise on detection and effectively improving detection accuracy.

[0095] It should be noted that, in one embodiment, when performing noise suppression on magnetic field signals, an adaptive Kalman filter may be used to establish a state equation to predict magnetic field changes, and random noise may be suppressed by iterative correction of observed values ​​(magnetic field signals sampled by magnetic detectors).

[0096] See also Figure 4 In some embodiments, step 304 includes step 402 and step 404 .

[0097] Step 402: Perform background magnetic field correction based on the preprocessed magnetic field signal to obtain a corrected magnetic field signal.

[0098] Step 404 : performing feature extraction and analysis based on the calibrated magnetic field signal to determine magnetic field state parameter information of the diaphragm.

[0099] Specifically, background magnetic field correction eliminates the influence of background magnetic fields on magnetic field signals. Background magnetic fields refer to the magnetic field signals recorded when the diaphragm is not transmitting to the detection area under the established test environment. In this way, the background magnetic field without the diaphragm is recorded as a baseline signal. During the subsequent diaphragm detection process, this background magnetic field is subtracted from the preprocessed magnetic field signal to obtain a corrected magnetic field signal for feature extraction and analysis.

[0100] In the above scheme, after filtering the magnetic field signal, the pre-processed magnetic field signal is further corrected for the background magnetic field, thereby reducing the impact of the background magnetic field on the detection accuracy and further improving the detection accuracy.

[0101] In the above embodiment, the magnetic field signal is first filtered and then the background magnetic field correction is performed. In other embodiments, the magnetic field signal may be first corrected for the background magnetic field and then filtered. There is no specific limitation and the selection can be made based on actual needs.

[0102] See also Figure 5 In some embodiments, the magnetic field state parameter information includes a magnetic field intensity peak value; step 206 includes step 502 and step 504 .

[0103] Step 502: When the peak value of the magnetic field intensity is greater than or equal to a preset peak value threshold, it is determined that magnetic metal particles exist in the diaphragm.

[0104] Step 504 : When the peak value of the magnetic field intensity is less than the preset peak value threshold, it is determined that no magnetic metal particles exist in the diaphragm.

[0105] Specifically, the peak value of the magnetic field intensity refers to the maximum value of the magnetic field intensity within a certain acquisition time. The preset peak threshold is the magnetic field intensity value that can be achieved when magnetic metal particles exist on the surface or inside the diaphragm under the current environment. As shown in the above embodiment, the magnetic detector can perform magnetic detection on the surface or inside of the diaphragm in real time to obtain the magnetic field intensity. The magnetic field intensity changes continuously with the increase of acquisition time (the magnetic field intensity at different locations is different), thereby forming a curve of the relationship between the magnetic field intensity and time. For details, please refer to Figure 6 In actual scenarios, considering that magnetic metal particles generally have a certain size, they will occupy a certain space in the tape running direction of the diaphragm. A certain acquisition time can be set as a detection cycle. During this acquisition time, the diaphragm will move a certain distance due to the tape running. At this time, a small section of the diaphragm is equivalent to being used as a detection area.

[0106] After that, the time-magnetic field strength relationship curve is analyzed in the time domain to identify the peak value of the magnetic field strength within the acquisition time period, and it is compared and analyzed with the preset peak value threshold. If it is greater than or equal to the preset peak value threshold, it is determined that magnetic metal particles exist in the detection area; if it is less than the preset peak value threshold, it is determined that no magnetic metal particles exist in the detection area.

[0107] It should be noted that the preset peak threshold value is not unique. In actual scenarios, it can be configured based on the thickness of the diaphragm, and the preset peak threshold value corresponding to different diaphragm thicknesses will also vary. In some embodiments, the processor pre-stores a correspondence between diaphragm thickness and peak threshold value. In actual scenarios, the processor can match the preset peak threshold value based on the acquired diaphragm thickness. For example, when the diaphragm thickness is 12 μm (micrometers), the preset peak threshold value can be set to 0.3 mT (miters).

[0108] The above solution uses the magnitude of the peak value of the magnetic field intensity in the magnetic field signal to analyze and determine whether magnetic metal particles exist in the diaphragm, and has a high judgment accuracy.

[0109] See also Figure 7 In some embodiments, the magnetic field state parameter information further includes peak pulse width, and step 206 further includes step 702 .

[0110] Step 702: Determine the size of the magnetic metal particles according to the peak pulse width and the tape travel speed of the diaphragm.

[0111] Specifically, peak pulse width refers to the duration of the peak magnetic field intensity; magnetic metal particle size refers to the relative length of the magnetic metal particles in the tape travel direction of the diaphragm. In actual detection scenarios, if magnetic metal particles are present in the diaphragm, the magnetic field intensity peak in the magnetic field signal will inevitably persist for a period of time due to the presence of magnetic metal particles in the tape travel direction. The length of the diaphragm during this period is the magnetic metal particle size, which is equal to the product of the peak pulse width and the tape travel speed.

[0112] It should be noted that, in one embodiment, due to measurement errors and other factors, the magnetic field intensity may fluctuate near the peak magnetic field intensity within the detection period corresponding to the magnetic metal particles. Therefore, in one embodiment, the peak pulse width can be determined based on the time period corresponding to the continuous occurrence of regions where the magnetic field signal is greater than or equal to a preset peak threshold before and after the magnetic field intensity peak.

[0113] The above scheme can also realize magnetic metal particle size analysis in combination with the peak pulse width of the magnetic field intensity peak value in the presence of magnetic metal particles, thereby identifying the size of the magnetic metal particles and having high accuracy in magnetic metal particle size analysis.

[0114] See also Figure 8 In some embodiments, the magnetic field state parameter information also includes a magnetic field energy value, and step 206 also includes step 802.

[0115] Step 802: Determine the type of magnetic metal particles according to the magnetic field energy value.

[0116] Specifically, the preset frequency band refers to a pre-set frequency band used for spectral energy calculation when performing frequency domain analysis on a magnetic field signal. This frequency band is not unique; for example, in one embodiment, it may be 1kHz-5kHz. In actual scenarios, after acquiring a time-magnetic field intensity magnetic field signal, frequency domain analysis can be performed on the signal to determine the magnetic field energy value of the magnetic metal particles within the preset frequency band.

[0117] In more detail, in one embodiment, wavelet transform analysis can be used to perform multi-scale decomposition of the magnetic field signal, extract higher frequency components (corresponding to smaller magnetic metal particles) and lower frequency components (corresponding to larger magnetic metal particles), and thereby calculate the magnetic field energy value of the magnetic metal particles within a preset frequency band.

[0118] In some embodiments, the calculated magnetic field energy value can be compared with the preset magnetic field threshold to determine whether the detection capability of the diaphragm detection device meets the detection requirements. The selection can be made based on actual needs.

[0119] The above solution can also determine the type of magnetic metal particles in the presence of magnetic metal particles by combining the magnetic field energy value within a preset frequency band, thereby meeting the needs of magnetic metal particle type identification scenarios and improving the reliability of diaphragm detection.

[0120] In some embodiments, step 802 includes: determining the type of magnetic metal particles according to matching the magnetic field energy value and a preset identification relationship; the preset identification relationship stores the types of magnetic metal particles corresponding to different magnetic field energy values.

[0121] Specifically, the preset identification relationship can be established through analysis of experimental data or historical data, and there is no specific limitation. The type of the preset identification relationship is not limited to a single type and can be in the form of a graph, table, or database, and there is no specific limitation.

[0122] In another embodiment, in order to improve the accuracy of the preset identification relationship, a preset identification relationship can be established based on the magnetic field energy value and combined with the amplitude (magnetic field intensity peak) and / or peak pulse width of the magnetic field signal (taking the above-mentioned time-magnetic field intensity curve as an example). In the subsequent identification process, after calculating the magnetic field energy value, it is only necessary to combine the magnetic field intensity peak and / or peak pulse width and substitute them into the preset identification relationship to determine the type of magnetic metal particles at this time.

[0123] The above solution determines the type of magnetic metal particles by matching the magnetic field energy value with the preset identification relationship, and has a high efficiency in identifying the type of magnetic metal particles.

[0124] In some embodiments, step 802 includes: performing inference analysis based on the magnetic field energy value and a preset recognition model to determine the type of magnetic metal particles; the preset recognition model is obtained by model training through the magnetic field signal of the actual production line.

[0125] Specifically, the preset recognition model is a preset model used to identify the type of magnetic metal particles. The actual production line magnetic field signal refers to the magnetic field signal of the actual production line where the diaphragm is located. This magnetic field signal can be collected through experiments on the actual production line and then input into the model for training to obtain the preset recognition model. The specific training method is not detailed here.

[0126] It should be noted that the type of training model is not unique. In one embodiment, a convolutional neural network (CNN) model may be used, and in other embodiments, other types of models may also be used, without specific limitation.

[0127] It can be understood that in some embodiments, in order to improve the accuracy of model training, mechanical vibration, electromagnetic interference, etc. of the actual production line can be introduced into the model for training, and the specific selection can be made based on actual needs.

[0128] The above solution determines the type of magnetic metal particles by combining the magnetic field energy value and the preset recognition model for inference analysis, and has a high accuracy in identifying the type of magnetic metal particles.

[0129] See also Figure 9 In some embodiments, the magnetic field state parameter information further includes the triggering time of the magnetic field intensity peak, and step 206 further includes step 902 .

[0130] Step 902: Determine the position of the magnetic metal particles according to the trigger time and the tape travel speed of the diaphragm.

[0131] Specifically, the trigger time of the magnetic field intensity peak refers to the time when the magnetic field intensity is detected to be greater than or equal to the preset peak threshold. As shown in the above embodiment, there will be certain fluctuations before and after the peak of the magnetic field intensity. As long as it is identified that the magnetic field intensity is greater than or equal to the preset peak threshold, it can be considered that magnetic metal particles are detected. In the time range when the magnetic field intensity is greater than or equal to the preset peak threshold, magnetic metal particles exist. Therefore, in actual scenarios, any time point within the time range when the magnetic field intensity is greater than or equal to the preset peak threshold can be used as the trigger time, and the selection can be made based on actual needs. For example, the time when the magnetic field intensity begins to be greater than or equal to the preset peak threshold can be used as the trigger time of the peak; in other embodiments, the time when the magnetic field intensity peak appears can also be used as the trigger time.

[0132] It should be pointed out that the starting point of the above-mentioned trigger time should correspond to the starting point of the diaphragm tape running. In this way, the actual tape running distance of the diaphragm can be determined by calculating the trigger time and the tape running speed of the diaphragm, and then the actual tape running distance of the diaphragm is used to characterize the position of the magnetic metal particles in the length direction of the diaphragm.

[0133] Furthermore, since the positions of the various magnetic detectors are relatively fixed, the position of each magnetic detector in the width direction of the diaphragm remains unchanged. The processor can obtain the position of the magnetic metal particles in the width direction of the diaphragm by judging and identifying the magnetic detector that has identified the above situation.

[0134] The above solution, in the presence of magnetic metal particles, can also combine the triggering time of the magnetic field intensity peak to analyze the position of the magnetic metal particles, thereby locating the diaphragm where the magnetic metal particles exist, with high position recognition accuracy.

[0135] In some embodiments, the method further includes: dynamically adjusting the sampling frequency of the magnetic field signal according to the feedback of the tape running speed of the diaphragm.

[0136] Specifically, during the detection process, the processor can obtain the tape speed of the diaphragm through relevant devices of the diaphragm production line (such as encoders), and adjust the sampling frequency of the magnetic detector (that is, the sampling frequency of the magnetic field signal) in combination with the resolution of the magnetic detector so that every position of the diaphragm can be sampled by the magnetic detector.

[0137] For example, in one embodiment, the tape speed of the diaphragm is v = 3.33 m / s (meters per second), the resolution d of the magnetic detector is 10 μm, and combined with the sampling frequency f = v / d, the final conversion result is that the sampling frequency f should be at least 333 kHz, so that every position point of the diaphragm can be sampled.

[0138] The above solution can also be combined with the real-time feedback of the diaphragm's tape running speed to adjust the sampling frequency of the magnetic detector, so that all positions in the diaphragm's tape running direction can be detected, further improving the accuracy of diaphragm detection.

[0139] Furthermore, in one embodiment, if the diaphragm's running speed fluctuates significantly (greater than a preset fluctuation range, such as ±5%), the magnetic detector can be switched to operate at the set sampling frequency until the diaphragm's running speed returns to normal. This can reduce the impact of the diaphragm's running speed on magnetic field signal acquisition and improve sampling accuracy.

[0140] See also Figure 10 , in some embodiments, step 202 includes step 1002 .

[0141] Step 1002 : performing differential calculation based on magnetic field acquisition signals at adjacent positions to determine the magnetic field signal of the diaphragm.

[0142] Specifically, this embodiment uses multiple magnetic detectors, each of which functions as a differential pair. Adjacent magnetic detectors use differential mode to measure magnetic field differences at the same location, eliminating interference from a uniform environment (such as the Earth's magnetic field). Specifically, the effective signal S0 = SA - SB, where SA and SB are the original magnetic field signals collected by the adjacent magnetic detectors.

[0143] The above solution uses adjacent magnetic detectors as a differential pair and eliminates environmental magnetic field interference through differential signal processing, thereby further improving the accuracy of diaphragm detection.

[0144] In some embodiments, the method further includes: outputting an exception handling instruction when the detection result indicates that magnetic metal particles exist in the diaphragm.

[0145] Specifically, the exception handling instruction is used to instruct to perform exception handling on the diaphragm having the magnetic metal particle portion, and the exception handling includes at least one of alarming, marking, and rejecting.

[0146] Abnormal processing is to process the abnormal part of the membrane containing magnetic metal particles to reduce the possibility of the abnormal part of the membrane flowing into subsequent working conditions. The abnormal processing method is not unique. This embodiment uses the abnormal processing component as an example to explain.

[0147] Correspondingly, the exception handling component includes at least one of a marking component, an alarm component and a sorting component. When magnetic metal particles are detected in the diaphragm, an alarm can be issued, the diaphragm with magnetic metal particles can be marked, the diaphragm with magnetic metal particles can be directly removed (such as cutting), or multiple operations can be performed at the same time. The specific selection can be made based on actual needs.

[0148] In the above scheme, when magnetic metal particles are present, the diaphragm containing magnetic metal particles can be abnormally handled by at least one of marking, alarming and rejecting, which greatly reduces the possibility of this part of the diaphragm flowing into subsequent processes and effectively improves the battery quality.

[0149] In some embodiments, after acquiring the magnetic field signals collected and transmitted by each magnetic detector, the processor may also perform signal fusion processing to obtain a magnetic field distribution map of the diaphragm, thereby helping the user understand the presence and distribution of magnetic metal particles in the diaphragm. Specifically, in practice, weighted superposition and spatial interpolation can be used to assign different weights (e.g., closer distances give higher weights) based on the distance between the magnetic detectors and the magnetic metal particles, to comprehensively calculate the magnetic field distortion. Linear interpolation is performed on areas not covered by the magnetic detectors' detection range (e.g., gaps between the magnetic detectors) to generate a complete magnetic field distribution map.

[0150] It is understood that the processor has a certain data storage function. In order to facilitate subsequent operations such as extraction of magnetic metal particle detection when required, the real-time acquisition results can be transmitted. Furthermore, in one embodiment, to reduce the amount of data, the processor can also store only the detection data where the magnetic field intensity is greater than or equal to a preset peak threshold to meet high-speed processing requirements.

[0151] In order to facilitate understanding of the technical solution of the present application, the present application is explained below in conjunction with more detailed embodiments.

[0152] There are multiple magnetic detectors, which are arranged into two rows of magnetic sensing arrays along the width direction of the diaphragm. The magnetic detectors of the two rows of magnetic sensing arrays are arranged alternately. At the same time, the diaphragm detection device is also equipped with a magnetic field enhancement component and a magnetic shielding component. The magnetic detectors and the magnetic field enhancement component are both located inside the magnetic shielding component.

[0153] The test starts at the start of the diaphragm's tape movement. During the diaphragm's tape movement, the magnetic detector's sampling frequency is dynamically adjusted based on the feedback of the diaphragm's tape movement speed. The diaphragm's magnetic field signal is acquired in real time. This magnetic field signal is represented by a curve showing the change in magnetic field intensity over sampling time. The processor first filters this magnetic field signal and corrects the background magnetic field to produce a corrected magnetic field signal.

[0154] After that, the processor performs time domain analysis and frequency domain analysis on the correction magnetic field signal to extract the peak value of the magnetic field intensity. When the peak value of the magnetic field intensity is greater than or equal to the preset peak threshold, it is determined that there are magnetic metal particles. If there are magnetic metal particles, the peak pulse width, the magnetic field energy value within the preset frequency band, and the triggering time of the magnetic field intensity peak are further determined through feature extraction analysis. The size of the magnetic metal particles can be calculated by combining the peak pulse width and the tape running speed of the diaphragm in the time period corresponding to the peak pulse width. The type of magnetic metal particles can be determined by matching and analyzing the magnetic field energy value, the magnetic field intensity peak, and the peak pulse width. Combined with the triggering time of the magnetic field intensity peak and the tape running speed of the diaphragm in different time periods before the triggering time, the position of the magnetic metal particles in the tape running direction of the diaphragm can be finally calculated.

[0155] Finally, after determining the position of the magnetic metal particles, the marking component can be controlled to mark the section of the diaphragm where the magnetic metal particles exist, or the sorting component can be controlled to remove the section of the diaphragm where the magnetic metal particles exist.

[0156] This solution has a high detection rate for magnetic metal particles, exceeding 99%, and boasts high accuracy in identifying magnetic metal particles with a diameter greater than or equal to 5µm. Furthermore, dynamic acquisition frequency adjustment enables real-time online detection, supporting high separator production line speeds. Furthermore, by inspecting the separator, the possibility of magnetic metal particles entering the battery is reduced, significantly improving battery performance.

[0157] Please refer to Figure 1 The present application provides a diaphragm detection device, including a processor 20 and at least one magnetic detector 10, the magnetic detector 10 is used to collect the magnetic field signal of the diaphragm; the processor is connected to the magnetic detector, and the processor is used to execute the steps of the above-mentioned diaphragm detection method.

[0158] Specifically, the implementation of the diaphragm detection method is as shown in the above-mentioned embodiments and will not be repeated here. In this solution, at least one magnetic detector 10 is set apart from the diaphragm. The magnetic field signal of the diaphragm is collected by the magnetic detector 10 and sent to the processor 20 for feature extraction and analysis, thereby determining the magnetic field state parameter information of the diaphragm. Then, combined with the magnetic field state parameter information, the detection result of the magnetic metal particles of the diaphragm is accurately obtained. Through this solution, the magnetic metal particles present in the diaphragm can be accurately identified by magnetic field signal recognition and analysis, thereby improving the quality of the diaphragm, reducing the possibility of the diaphragm containing magnetic metal particles flowing into the subsequent process, and greatly improving the quality of the battery.

[0159] The number of magnetic detectors 10 is not unique. When there are multiple magnetic detectors 10, each magnetic detector 10 can be arranged in a regular or irregular manner, as long as the collection area corresponding to each magnetic detector 10 can be fully covered as much as possible over the width of the diaphragm.

[0160] In some embodiments, there are multiple magnetic detectors 10 , and the multiple magnetic detectors 10 are arranged along the width direction of the diaphragm; the width direction is perpendicular to the running direction of the diaphragm.

[0161] In the solution of this embodiment, multiple magnetic detection devices are arranged in a regular manner, specifically along the width direction of the diaphragm, so that magnetic field signals at various positions in the width direction can be collected through the tape running of the diaphragm.

[0162] In the above solution, a plurality of magnetic detectors 10 are configured in the diaphragm detection device and are arranged along the width direction perpendicular to the diaphragm running direction. In this way, it is only necessary to fix the magnetic detector 10 and detect each position of the diaphragm through the running of the diaphragm, which has high detection accuracy.

[0163] Furthermore, in some embodiments, a plurality of magnetic detectors 10 are arranged in a magnetic sensing array along the width direction of the diaphragm.

[0164] Specifically, in this embodiment, the distance between any two adjacent magnetic detectors 10 in the same magnetic sensing array column should be sufficiently small so that the gap between adjacent magnetic detectors 10 can still capture magnetic field signals, thereby reducing the possibility of missed detections. Specifically, the distance between adjacent magnetic detectors 10 can be selected based on the size of the magnetic detectors 10 and the detection range of the magnetic detectors 10, and is not specifically limited.

[0165] It should be noted that the distance between any two adjacent magnetic detectors 10 can be set to be the same or different, and there is no specific limitation, as long as the gap between the adjacent magnetic detectors 10 is within the detection range of the magnetic detector 10.

[0166] In more detail, in one embodiment, the distance between any two adjacent magnetic detectors 10 in the same column of the magnetic sensing array is 0, that is, the magnetic detectors 10 are closely arranged along the width direction.

[0167] In the above solution, multiple magnetic detectors 10 are arranged in a row along the width direction of the diaphragm, so as to realize detection of different positions of the diaphragm, and can also effectively reduce the number of magnetic detectors 10 and save hardware costs.

[0168] See also Figure 11 In some embodiments, multiple magnetic detectors 10 are arranged into multiple columns of magnetic sensing arrays along the width direction of the diaphragm (two columns are taken as an example in the figure), and the projection of the magnetic detector 10 in any column of the magnetic sensing array in the tape running direction is located between two magnetic detectors 10 in adjacent magnetic sensing arrays.

[0169] Specifically, to further reduce the possibility of missed detection, multiple columns of magnetic sensing arrays can be configured. Each column includes multiple magnetic detectors 10 arranged along the width of the diaphragm. This arrangement provides transverse (widthwise) coverage and longitudinal (tape-tracking) redundancy, enabling reliable magnetic field signal acquisition. The number of magnetic sensing arrays is not unique; the figure uses two columns as an example for illustration.

[0170] Both rows of magnetic sensing arrays extend along the width of the diaphragm. The first row contains 10 magnetic sensors 10, with a distance a between each. The second row contains 9 magnetic sensors 10, also spaced a apart. The projection of any magnetic sensor 10 in the second row, along the tape run direction, is located between two adjacent magnetic sensors 10 in the first row. This staggered arrangement ultimately enables detection of magnetic field signals from the diaphragm.

[0171] In the above solution, the magnetic detectors 10 are arranged in multiple columns along the width direction of the diaphragm, and the magnetic detectors 10 in each column are staggered, so that any position in the width direction of the diaphragm can effectively detect the magnetic field signal, reducing the possibility of missed detection.

[0172] See also Figure 12 In some embodiments, the diaphragm detection device further includes a magnetic shielding assembly 40 , and the magnetic detector 10 is disposed inside the magnetic shielding assembly 40 .

[0173] Specifically, the magnetic shield assembly 40 is a device that shields magnetic field energy, reducing the interaction between the magnetic field within the magnetic shield assembly 40 and external magnetic fields (such as those generated by motors and power lines). By placing the magnetic detector 10 within the magnetic shield assembly 40, external magnetic field interference on the magnetic detector 10 is reduced, improving the accuracy of magnetic field signal detection.

[0174] It should be noted that, in one embodiment, in order to facilitate diaphragm detection during diaphragm tape running, the magnetic shielding assembly 40 should include at least two openings, so that the diaphragm enters from one opening and exits from the other opening.

[0175] In the above solution, the magnetic detector 10 is disposed inside the magnetic shielding assembly 40 , which can effectively reduce the interference of the external environment on the magnetic detector 10 and improve the accuracy of collecting magnetic field signals.

[0176] See also Figure 13 In some embodiments, the diaphragm detection device further includes a magnetic field enhancement component 50 , which is spaced apart from the diaphragm and configured to apply a magnetic field to the collection area of ​​the magnetic detector 10 .

[0177] Specifically, the magnetic field enhancement component 50 can apply a magnetic field to the collection area of ​​the magnetic detector 10, thereby enhancing the magnetism of weakly magnetic (or micron-level) magnetic metal particles on the surface or inside the diaphragm, so that these metal particles can also be detected by the magnetic detector 10, thereby improving the detection capability of the magnetic field signal.

[0178] It should be noted that the magnetic field enhancement assembly 50 is not limited to a single type. In one embodiment, the magnetic field can be applied by applying an external electric field, for example, by energizing electrode plates. In other embodiments, the magnetic field enhancement assembly 50 can be constructed from other magnetic materials to achieve magnetic field application. The choice of material will be determined based on actual needs.

[0179] In the above solution, the magnetic field enhancement component 50 applies a magnetic field to the collection area of ​​the magnetic detector 10, thereby enhancing the magnetic field in the collection area, that is, enhancing the magnetism of the magnetic metal particles, thereby effectively improving the collection reliability of the magnetic field signal.

[0180] See also Figure 14 In some embodiments, the diaphragm detection device further includes an exception handling component 30 connected to the processor 20, and the exception handling component 30 is used to respond to an exception handling instruction sent by the processor 20 to perform exception handling on the diaphragm having a magnetic metal particle portion.

[0181] In some embodiments, the exception handling component 30 includes at least one of a marking component, an alarm component, and a sorting component. The marking component is used to mark the diaphragm containing magnetic metal particles, the alarm component is used to output an alarm signal, and the sorting component is used to remove the diaphragm containing magnetic metal particles.

[0182] In the above scheme, when magnetic metal particles are present, the diaphragm containing magnetic metal particles can be abnormally handled by at least one of marking, alarming and rejecting, which greatly reduces the possibility of this part of the diaphragm flowing into subsequent processes and effectively improves the battery quality.

[0183] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A diaphragm detection method, characterized in that: include: Performing differential calculations based on magnetic field acquisition signals at adjacent positions to determine the magnetic field signal of the diaphragm; wherein the magnetic field acquisition signals at adjacent positions are acquired by adjacent magnetic detectors, the magnetic detectors being spaced apart from the diaphragm and completely covering the diaphragm in the width direction; Performing feature extraction and analysis on the magnetic field signal to determine magnetic field state parameter information of the diaphragm; the magnetic field state parameter information is used to characterize the magnetic field distribution state of the diaphragm; determining a detection result of magnetic metal particles of the diaphragm according to the magnetic field state parameter information; The magnetic field state parameter information includes a peak pulse width, and determining the detection result of the magnetic metal particles of the diaphragm based on the magnetic field state parameter information includes: determining the size of the magnetic metal particles based on the peak pulse width and the tape running speed of the diaphragm.

2. The diaphragm detection method according to claim 1, characterized in that: The performing feature extraction and analysis based on the magnetic field signal to determine the magnetic field state parameter information of the diaphragm includes: Performing filtering processing on the magnetic field signal to obtain a preprocessed magnetic field signal; Feature extraction and analysis are performed based on the preprocessed magnetic field signal to determine magnetic field state parameter information of the diaphragm.

3. The diaphragm detection method according to claim 2, characterized in that: The performing feature extraction and analysis based on the preprocessed magnetic field signal to determine the magnetic field state parameter information of the diaphragm includes: Performing background magnetic field correction according to the preprocessed magnetic field signal to obtain a corrected magnetic field signal; Feature extraction and analysis are performed based on the correction magnetic field signal to determine magnetic field state parameter information of the diaphragm.

4. The diaphragm detection method according to claim 1, characterized in that: The magnetic field state parameter information includes a magnetic field intensity peak value; and determining the detection result of the magnetic metal particles of the diaphragm according to the magnetic field state parameter information includes: When the peak value of the magnetic field intensity is greater than or equal to a preset peak value threshold, it is determined that magnetic metal particles exist in the diaphragm; When the peak value of the magnetic field intensity is less than the preset peak value threshold, it is determined that no magnetic metal particles exist in the diaphragm.

5. The diaphragm detection method according to any one of claims 1 to 4, characterized in that: The magnetic field state parameter information further includes a magnetic field energy value. Determining the detection result of the magnetic metal particles of the diaphragm according to the magnetic field state parameter information includes: The type of magnetic metal particles is determined according to the magnetic field energy value.

6. The diaphragm detection method according to claim 5, characterized in that: Determining the type of magnetic metal particles according to the magnetic field energy value includes: The magnetic metal particle type is determined by matching the magnetic field energy value with a preset identification relationship; the preset identification relationship stores the magnetic metal particle types corresponding to different magnetic field energy values.

7. The diaphragm detection method according to claim 5, characterized in that: Determining the type of magnetic metal particles according to the magnetic field energy value includes: The type of magnetic metal particles is determined by performing inference analysis based on the magnetic field energy value and a preset recognition model; the preset recognition model is obtained by model training using magnetic field signals from an actual production line.

8. The diaphragm detection method according to any one of claims 1 to 4, characterized in that: The magnetic field state parameter information also includes a trigger time of a magnetic field intensity peak. Determining the detection result of the magnetic metal particles of the diaphragm according to the magnetic field state parameter information includes: The position of the magnetic metal particles is determined according to the triggering time and the tape running speed of the diaphragm.

9. The diaphragm detection method according to any one of claims 1 to 4, characterized in that: The method further comprises: The sampling frequency of the magnetic field signal is dynamically adjusted according to the feedback of the tape running speed of the diaphragm.

10. The diaphragm detection method according to any one of claims 1 to 4, characterized in that: The method further comprises: When the detection result indicates that magnetic metal particles exist in the diaphragm, an exception handling instruction is output; the exception handling instruction is used to instruct the diaphragm to perform exception handling on the portion containing magnetic metal particles, and the exception handling includes at least one of alarm, marking and rejection.

11. A diaphragm detection device, characterized in that: include: A plurality of magnetic detectors, each of which is used to collect magnetic field signals of the diaphragm; A processor is connected to the magnetic detector, and the processor is used to execute the steps of the diaphragm detection method according to any one of claims 1 to 10.

12. The diaphragm detection device according to claim 11, characterized in that: The plurality of magnetic detectors are arranged along the width direction of the diaphragm; the width direction is perpendicular to the running direction of the diaphragm.

13. The diaphragm detection device according to claim 12, characterized in that: The plurality of magnetic detectors are arranged in a magnetic sensing array along the width direction of the diaphragm.

14. The diaphragm detection device according to claim 12, characterized in that: The plurality of magnetic detectors are arranged into a plurality of columns of magnetic sensing arrays along the width direction of the diaphragm, and the projection of the magnetic detectors in any column of the magnetic sensing array in the tape running direction is located between two magnetic detectors in adjacent magnetic sensing arrays.

15. The diaphragm detection device according to claim 11, characterized in that: The diaphragm detection device further includes a magnetic shielding component, and the magnetic detector is arranged inside the magnetic shielding component.

16. The diaphragm detection device according to claim 11, characterized in that: The diaphragm detection device further includes a magnetic field enhancement component, which is used to apply a magnetic field to the collection area of ​​the magnetic detector.

17. The diaphragm detection device according to claim 11, characterized in that: The device further includes an exception processing component, which is configured to respond to an exception processing instruction sent by the processor to perform exception processing on the diaphragm having the magnetic metal particle portion.

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