Die Cutting System and Method

Abstract

The present invention discloses a die-cutting system and method. The system includes: a sensor, a controller, and a laser; the sensor is used to collect the pole piece thickness data of the pole piece and send the pole piece thickness data to the controller; the controller is used to determine the starting point of the thickness thinning area according to the change of the pole piece thickness data, calculate the first distance from the starting point of the thickness thinning area to the laser, calculate the die-cutting waiting time according to the first distance, and send the die-cutting waiting time to the laser; the laser is used to perform die-cutting on the pole piece after an interval of the die-cutting waiting time to obtain a first tab; since the present application determines the starting point of the thickness thinning area according to the change of the pole piece thickness and guides the laser to cut the first tab according to the starting point of the thickness thinning area, it can accurately identify the position of the thickness thinning area in the die-cutting process, and further can accurately cut the first tab at the designed distance in front of the thickness thinning area in the die-cutting process, so that the thickness thinning area is at the corner of the cell winding.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a die-cutting system and method. Background Art

[0002] In the existing coating production process, a layer of slurry is evenly coated on the electrode sheet. After a series of operations such as rolling, die-cutting, winding, and compaction are performed on the coating to form an electric core, coating peeling may occur at the corners, causing lithium plating in the electric core and resulting in safety accidents. Therefore, in order to overcome the above defects, a new coating process is proposed in the related art, that is, using a dual die head. The first die head evenly coats a layer, and the second die head coats another layer at intervals (coating gap length) on the basis of the first coating, which is the second coating.

[0003] In the winding stage, in order to make the thickness thinning area at the corner of the winding of the electric core, it is necessary to accurately cut the first pole ear at the designed distance in front of the thickness thinning area in the die-cutting process. Therefore, how to accurately cut the first pole ear at the designed distance in front of the thickness thinning area in the die-cutting process is a technical problem to be solved urgently. Summary of the Invention

[0004] In view of the above problems, the present invention provides a die-cutting system and method, aiming to solve the problem of how to accurately cut the first pole ear at the designed distance in front of the thickness thinning area in the die-cutting process.

[0005] In a first aspect, the present invention provides a die-cutting system, and the die-cutting system includes: a sensor, a controller, and a laser;

[0006] The sensor is used to collect the electrode sheet thickness data of the electrode sheet and send the electrode sheet thickness data to the controller;

[0007] The controller is used to determine the starting point of the thickness thinning area according to the change of the electrode sheet thickness data, calculate the first distance from the starting point of the thickness thinning area to the laser, calculate the die-cutting waiting time according to the first distance, and send the die-cutting waiting time to the laser;

[0008] The laser is used to perform die-cutting on the electrode sheet after the die-cutting waiting time to obtain the first pole ear.

[0009] In the technical solution of the embodiment of the present invention, the starting point of the thickness thinning area is determined by measuring the change of the electrode sheet thickness data, and the laser is guided to cut the first pole ear according to the starting point of the thickness thinning area, so that the position of the thickness thinning area can be accurately identified in the die-cutting process, and further, the first pole ear can be accurately cut at the designed distance in front of the thickness thinning area in the die-cutting process, so that the thickness thinning area is at the corner of the winding of the electric core.

[0010] In some embodiments, the die-cutting system further includes: an encoder, an image collector, and a coding roller corresponding to the encoder; when the pole piece is running, the coding roller is driven to rotate, and the rotation of the coding roller drives the encoder to trigger a pulse;

[0011] The sensor is configured to collect pole piece thickness data of the pole piece in response to the pulse and send the pole piece thickness data to the controller;

[0012] The image collector is configured to collect an image of the die-cut pole piece in response to the pulse and send the image of the die-cut pole piece to the controller;

[0013] The controller is configured to perform defect detection on the die-cut pole piece according to the image of the die-cut pole piece.

[0014] In the technical solution of the embodiment of the present invention, a pulse is triggered when the pole piece is running, and in response to the pulse, the pole piece thickness data of the pole piece and the image of the die-cut pole piece are collected, so that the consistency between the pole piece running and the pole piece detection can be achieved, and further the accuracy of the pole piece detection can be improved.

[0015] In some embodiments, the die-cutting waiting time is the number of die-cutting waiting pulses;

[0016] The controller is further configured to obtain the encoder accuracy of the encoder and calculate the number of die-cutting waiting pulses according to the pulse accuracy and the first distance; send the number of die-cutting waiting pulses to the laser;

[0017] The laser is further configured to perform die-cutting on the pole piece after the number of die-cutting waiting pulses to obtain a first tab.

[0018] In the technical solution of the embodiment of the present invention, the number of die-cutting waiting pulses is calculated according to the encoder accuracy, and after the number of die-cutting waiting pulses, the laser is controlled to perform die-cutting on the pole piece to obtain a first tab, so that the influence of the pole piece running speed on the die-cutting of the first tab by the laser can be reduced, and further the accuracy of the die-cutting of the first tab can be improved.

[0019] In some embodiments, the controller is further configured to obtain the die-cutting error of the first tab according to the image of the die-cut pole piece; if the die-cutting error is not within the preset error range, an error correction instruction is generated according to the die-cutting error;

[0020] The laser is further configured to perform die-cutting on the pole piece according to the error correction instruction after the die-cutting waiting time to obtain the next first tab.

[0021] In the technical solution of the embodiment of the present invention, the die-cutting error of the first tab is obtained through the image of the die-cut pole piece. If the die-cutting error is not within the preset error range, an error correction instruction is generated according to the die-cutting error to control the laser, so as to form a complete closed-loop detection system, and then the process of the laser die-cutting the first tab can be corrected in time, improving the reliability of the die-cutting system.

[0022] In some embodiments, the controller is further configured to obtain a second distance from the sensor to the laser, and obtain the running distance of the pole piece when the sensor collects the pole piece thickness data; calculate a first distance from the starting point of the thickness thinning area to the laser according to the second distance and the running distance.

[0023] In the technical solution of the embodiment of the present invention, when calculating the first distance, the second distance from the sensor to the laser and the running distance of the pole piece when the sensor collects the pole piece thickness data are also considered, so as to improve the accuracy of the first distance calculation, and then improve the accuracy of the first tab die-cutting.

[0024] In some embodiments, the sensor, the laser, the coding roller and the image collector are sequentially arranged in the running direction of the pole piece. The data collection direction of the sensor is perpendicular to the running direction of the pole piece, the light outlet of the laser is perpendicular to the running direction of the pole piece, and the image collection direction of the image collector is perpendicular to the running direction of the pole piece.

[0025] In the technical solution of the embodiment of the present invention, the sensor, the laser, the coding roller and the image collector are sequentially arranged in the running direction of the pole piece, and the data collection and laser die-cutting directions are set perpendicular to the running direction of the pole piece, so as to improve the accuracy of data collection and laser die-cutting.

[0026] In some embodiments, the sensor includes a first sensor and a second sensor. The first sensor and the second sensor are arranged on both sides of the pole piece in a opposed form, and the data collection directions of the first sensor and the second sensor are perpendicular to the pole piece.

[0027] In the technical solution of the embodiment of the present invention, the first sensor and the second sensor are respectively arranged on both sides of the pole piece, and the first sensor and the second sensor collect the pole piece thickness data in a opposed form, so as to improve the accuracy of the pole piece thickness data.

[0028] In some embodiments, the image collector includes a first image collector, a second image collector, a third image collector and a fourth image collector;

[0029] The first image collector is used to detect the front defect of the die-cut pole piece;

[0030] The second image collector is configured to detect the backlight defects of the die-cut pole piece.

[0031] The third image collector and the fourth image collector are configured to detect the reverse side defects of the die-cut pole piece.

[0032] In the technical solution of the embodiment of the present invention, multiple image collectors are arranged at multiple positions to detect the defects of the pole piece, so as to improve the comprehensiveness and accuracy of the pole piece defect detection.

[0033] In some embodiments, the first image collector includes a first camera and a first light source, and the first camera and the first light source are arranged on the same side of the pole piece; the second image collector includes a second camera and a second light source, and the second camera and the second light source are respectively arranged on both sides of the pole piece; the third image collector includes a third camera and a third light source, and the third camera and the third light source are arranged on the same side of the pole piece; the fourth image collector includes a fourth camera and a fourth light source, and the fourth camera and the fourth light source are arranged on the same side of the pole piece.

[0034] In the technical solution of the embodiment of the present invention, the first image collector, the third image collector and the fourth image collector adopt coaxial light, that is, the camera and the light source are arranged on the same side of the pole piece and perpendicular to the pole piece, and the second image collector adopts a backlight lighting method, that is, the camera and the light source are respectively arranged on both sides of the pole piece and perpendicular to the pole piece, so as to improve the image acquisition effect of the image collector.

[0035] In some embodiments, the controller is further configured to obtain the inflection point coordinates of the thickness thinning area and the starting point coordinates of each pole piece strip, where the pole piece strip is the strip corresponding to the pole piece of one cell length; calculate the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the starting point coordinates of each pole piece strip.

[0036] In the technical solution of the embodiment of the present invention, the length of the thickness thinning area is calculated according to the inflection point coordinates of the thickness thinning area, and the length of each pole piece strip is calculated according to the starting point coordinates of each pole piece strip, so as to accurately calculate the length of the thickness thinning area and the length of each pole piece strip.

[0037] In some embodiments, the die-cutting system further includes: a calibration scale, and the calibration scale is arranged on the coding roller; the coding roller rotates to drive the calibration scale to rotate, and the coding roller rotates to drive the encoder to trigger a calibration pulse;

[0038] The image collector is further configured to collect a calibration image of the calibration scale in response to the calibration pulse and send the calibration image to the controller;

[0039] The controller is further configured to obtain the calibration scale parameters of the calibration scale, calculate the calibration accuracy according to the calibration image and the calibration scale parameters, where the calibration accuracy is used to represent the mapping relationship between the pixel distance and the actual distance; calculate the length of the thickness thinning area according to the calibration accuracy and the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the calibration accuracy and the starting point coordinates of each pole piece strip.

[0040] In the technical solution of the embodiment of the present invention, by calibrating the image collector, the sensor is indirectly calibrated, so that the target calibration accuracy can be determined, and the accuracy of calculating the length of the thickness thinning area and the length of each pole piece strip subsequently can be improved.

[0041] In some embodiments, the sensor is a spectral confocal displacement sensor, and the spectral confocal displacement sensor includes: a point light source, a dispersion confocal probe, a spectroscopic component, and a detector;

[0042] The point light source is configured to emit detection light to the pole piece, and the detection light forms detection light of different wavelengths after passing through the dispersion confocal probe. Wherein, when the detection light of different wavelengths irradiates the pole piece, the return light of the pole piece is connected to the detector through the spectroscopic component, and the spectroscopic component is configured to block the light of non-focusing wavelengths in the return light;

[0043] The detector is configured to obtain the light wavelength of the return light, and look up the pole piece thickness data corresponding to the light wavelength in a preset wavelength relationship table, where the preset wavelength relationship table includes the corresponding relationship between the light wavelength and the pole piece thickness data; and send the pole piece thickness data to the controller.

[0044] In the technical solution of the embodiment of the present invention, the sensor is set as a spectral confocal displacement sensor, so that the volume of the sensor can be reduced, the measurement blind area can be reduced, and the anti-interference ability can be improved.

[0045] In a second aspect, the present invention provides a die-cutting method, including:

[0046] Collect the pole piece thickness data of the pole piece;

[0047] Determine the starting point of the thickness thinning area according to the change of the pole piece thickness data, calculate the first distance from the starting point of the thickness thinning area to the die-cutting position of the pole piece, and calculate the die-cutting waiting time according to the first distance;

[0048] After the die-cutting waiting time has elapsed, perform die-cutting on the pole piece at the die-cutting position of the pole piece to obtain a first pole ear.

[0049] In the technical solution of the embodiment of the present invention, by measuring the change of the pole piece thickness data to determine the starting point of the thickness thinning area, and guiding the laser to cut the first pole ear according to the starting point of the thickness thinning area, it is possible to accurately identify the position of the thickness thinning area in the die-cutting process, and further accurately cut the first pole ear at the designed distance before the thickness thinning area in the die-cutting process, so that the thickness thinning area is at the corner of the core winding.

[0050] In some embodiments, before collecting the pole piece thickness data of the pole piece, it further includes:

[0051] When the pole piece is running, trigger a pulse;

[0052] The collection of the pole piece thickness data of the pole piece includes:

[0053] In response to the pulse, collect the pole piece thickness data of the pole piece;

[0054] After waiting for the die-cutting time interval and performing die-cutting on the pole piece at the die-cutting position of the pole piece to obtain the first pole ear, it further includes:

[0055] In response to the pulse, collect the image of the die-cut pole piece, and perform defect detection on the die-cut pole piece according to the image of the die-cut pole piece.

[0056] In the technical solution of the embodiment of the present invention, a pulse is triggered when the pole piece is running, and in response to the pulse, the pole piece thickness data of the pole piece and the image of the die-cut pole piece are collected, so as to achieve the consistency of the pole piece running and the pole piece detection, and further improve the accuracy of the pole piece detection.

[0057] In some embodiments, the die-cutting waiting time is the number of die-cutting waiting pulses; the calculation of the die-cutting waiting time according to the first distance includes:

[0058] Obtain the pulse precision of the pulse;

[0059] Calculate the number of die-cutting waiting pulses according to the pulse precision and the first distance;

[0060] Correspondingly, after waiting for the die-cutting time interval, performing die-cutting on the pole piece at the die-cutting position of the pole piece to obtain the first pole ear includes:

[0061] After waiting for the number of die-cutting waiting pulses, perform die-cutting on the pole piece at the die-cutting position of the pole piece to obtain the first pole ear.

[0062] In the technical solution of the embodiment of the present invention, the number of die-cutting waiting pulses is calculated according to the pulse precision, and after waiting for the number of die-cutting waiting pulses, the pole piece is die-cut to obtain the first pole ear, so as to reduce the influence of the pole piece running speed on the die-cutting of the first pole ear, and further improve the accuracy of the die-cutting of the first pole ear.

[0063] In some embodiments, after the die-cutting waiting time has elapsed and die-cutting is performed on the pole piece at the pole piece die-cutting position to obtain the first tab, the method further includes:

[0064] Obtaining the die-cutting error of the first tab according to the image of the pole piece after die-cutting;

[0065] If the die-cutting error is not within the preset error range, generating an error correction instruction according to the die-cutting error;

[0066] After the die-cutting waiting time has elapsed, die-cutting is performed on the pole piece at the pole piece die-cutting position according to the error correction instruction to obtain the next first tab.

[0067] In the technical solution of the embodiments of the present invention, the die-cutting error of the first tab is obtained through the image of the pole piece after die-cutting. If the die-cutting error is not within the preset error range, an error correction instruction is generated according to the die-cutting error to control the laser, thereby forming a complete closed-loop detection system, and then the process of the laser die-cutting the first tab can be corrected in a timely manner, improving the reliability of the die-cutting system.

[0068] In some embodiments, calculating the first distance from the starting point of the thickness thinning area to the pole piece die-cutting position includes:

[0069] Obtaining the second distance between the acquisition position of the pole piece thickness data and the pole piece die-cutting position;

[0070] Obtaining the running distance of the pole piece when the pole piece thickness data is acquired;

[0071] Calculating the first distance from the starting point of the thickness thinning area to the pole piece die-cutting position according to the second distance and the running distance.

[0072] In the technical solution of the embodiments of the present invention, when calculating the first distance, the second distance from the sensor to the laser and the running distance of the pole piece when the sensor acquires the pole piece thickness data are also considered, so as to improve the accuracy of the first distance calculation, and then improve the accuracy of the first tab die-cutting.

[0073] In some embodiments, defect detection of the pole piece after die-cutting according to the image of the pole piece after die-cutting includes:

[0074] Obtaining the frequency characteristics of the image of the pole piece after die-cutting, and removing noise from the image of the pole piece after die-cutting according to the frequency characteristics to obtain a processed image;

[0075] Obtaining the edge texture image of the pole piece after die-cutting according to the image of the pole piece after die-cutting and the processed image;

[0076] Defect detection is performed on the die-cut pole piece according to the edge texture image.

[0077] In the technical solution of the embodiment of the present invention, first, the frequency characteristics of the image of the die-cut pole piece are obtained, then noise removal is performed on the image of the die-cut pole piece according to the frequency characteristics to obtain a processed image, and then the edge texture image of the die-cut pole piece is obtained based on the image of the die-cut pole piece and the processed image, and defect detection is performed on the die-cut pole piece according to the edge texture image, so as to improve the accuracy of gap coating trailing detection.

[0078] In some embodiments, determining the starting point of the thickness thinning area according to the change of the pole piece thickness data includes:

[0079] Constructing an objective function according to the pole piece thickness data, where the objective function is used to represent the thickness change of the pole piece;

[0080] Determining the inflection point of the thickness thinning area according to the objective function;

[0081] Determining the starting point of the thickness thinning area according to the inflection point of the thickness thinning area and the running direction of the pole piece.

[0082] In the technical solution of the embodiment of the present invention, first, an objective function is constructed according to the pole piece thickness data, then the inflection point of the thickness thinning area is determined according to the objective function, and the starting point of the thickness thinning area is determined according to the inflection point of the thickness thinning area and the running direction of the pole piece, so as to improve the accuracy of the starting point of the thickness thinning area.

[0083] In some embodiments, determining the inflection point of the thickness thinning area according to the objective function includes:

[0084] Calculating the intersection points between a preset threshold and the objective function;

[0085] Determining the inflection point of the thickness thinning area according to the intersection points.

[0086] In the technical solution of the embodiment of the present invention, by calculating the intersection points between a preset threshold and the derivative of the logical function, and determining the inflection point of the thickness thinning area according to the intersection points, the inflection point of the thickness thinning area can be calculated.

[0087] In some embodiments, determining the inflection point of the thickness thinning area according to the objective function includes:

[0088] Calculating the maximum or minimum value of the objective function;

[0089] Determining the inflection point of the thickness thinning area according to the maximum or minimum value.

[0090] In the technical solution of the embodiment of the present invention, the inflection point of the thickness thinning area is determined based on the measurement scheme of the steepest descent / steepest ascent point, so that the accuracy of the inflection point of the coating gap can be improved, and further the calculation accuracy of the length of the thickness thinning area and the length of each pole piece strip can be improved.

[0091] In some embodiments, after determining the inflection point of the thickness thinning area according to the objective function, it further includes:

[0092] Obtain the inflection point coordinates of the thickness thinning area and the starting point coordinates of each pole piece strip, where the pole piece strip is the strip corresponding to the pole piece of one battery cell length;

[0093] Calculate the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the starting point coordinates of each pole piece strip.

[0094] In the technical solution of the embodiment of the present invention, the length of the thickness thinning area is calculated according to the inflection point coordinates of the thickness thinning area, and the length of each pole piece strip is calculated according to the starting point coordinates of each pole piece strip, so that the length of the thickness thinning area and the length of each pole piece strip can be accurately calculated.

[0095] In some embodiments, before calculating the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area and calculating the length of each pole piece strip according to the starting point coordinates of each pole piece strip, it further includes:

[0096] Collect the calibration image of the calibration ruler and obtain the calibration ruler parameters of the calibration ruler;

[0097] Calculate the calibration accuracy according to the calibration image and the calibration ruler parameters, where the calibration accuracy is used to represent the mapping relationship between the pixel distance and the actual distance;

[0098] Correspondingly, calculating the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area and calculating the length of each pole piece strip according to the starting point coordinates of each pole piece strip includes:

[0099] Calculate the length of the thickness thinning area according to the calibration accuracy and the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the calibration accuracy and the starting point coordinates of each pole piece strip.

[0100] In the technical solution of the embodiment of the present invention, by calibrating the image collector, the sensor is indirectly calibrated, so that the target calibration accuracy can be determined, and the accuracy of calculating the length of the thickness thinning area and the length of each pole piece strip subsequently can be improved.

[0101] In some embodiments, collecting the pole piece thickness data of the pole piece includes:

[0102] Detecting light rays of different wavelengths are emitted to the pole piece. Among them, when the detecting light rays of different wavelengths irradiate the pole piece, the light rays with unfocused wavelengths in the return light rays of the pole piece are blocked;

[0103] Receive the return light rays of the pole piece, obtain the light wavelengths of the return light rays, and look up the corresponding pole piece thickness data of the light wavelengths in a preset wavelength relationship table, where the preset wavelength relationship table includes the corresponding relationship between the light wavelengths and the pole piece thickness data.

[0104] In the technical solution of the embodiment of the present invention, the pole piece thickness data is collected through the light wavelengths of the return light rays of the pole piece, so that the volume of the sensor can be reduced, the measurement blind area can be reduced, and the anti-interference ability can be improved.

[0105] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are specifically given below. Description of the Drawings

[0106] Figure 1 It is a schematic diagram of a new coating process;

[0107] Figure 2 It is a schematic diagram of gap coating;

[0108] Figure 3 It is a schematic diagram of the pole piece after roll pressing and slitting;

[0109] Figure 4 It is a schematic diagram of the pole piece after die cutting and slitting;

[0110] Figure 5 It is a schematic diagram of a die cutting system according to some embodiments of the present invention;

[0111] Figure 6 It is a tape running schematic diagram of a die cutting system according to some embodiments of the present invention;

[0112] Figure 7 It is a schematic diagram of a die cutting system according to some embodiments of the present invention;

[0113] Figure 8 It is a tape running schematic diagram of a die cutting system according to some embodiments of the present invention;

[0114] Figure 9 It is a tape running schematic diagram of a die cutting system according to some embodiments of the present invention;

[0115] Figure 10 It is a thickness schematic diagram of a thickness thinning area according to some embodiments of the present invention;

[0116] Figure 11 Schematic diagram of the calibration ruler for some embodiments of the present invention;

[0117] Figure 12 Schematic diagram of the calibration image for some embodiments of the present invention;

[0118] Figure 13 Schematic diagram of thickness measurement by the opposed arrangement of the spectral confocal displacement sensor for some embodiments of the present invention;

[0119] Figure 14 Flowchart of the gap die-cutting deviation correction method for some embodiments of the present invention;

[0120] Figure 15 Flowchart of the gap die-cutting deviation correction method for some embodiments of the present invention;

[0121] Figure 16 Flowchart of the gap die-cutting deviation correction method for some embodiments of the present invention;

[0122] Figure 17 Three-view drawing of the image collector for some embodiments of the present invention;

[0123] Figure 18 Schematic diagram of finding the inflection point of the thickness thinning area for some embodiments of the present invention;

[0124] Figure 19 Schematic diagram of finding the inflection point of the thickness thinning area for some embodiments of the present invention.

[0125] The reference numerals in the specific embodiments are as follows:

[0126] Thickness thinning area 10, film area 11, foil 12, first coating 13, second coating 14, tab area 20, first tab 40, sensor 50, laser 51, over-roller 60, encoder 61, coding roller 62, image collector 63, first sensor 80, second sensor 81, first image collector 91, second image collector 92, third image collector 93, fourth image collector 94, first marking machine 95, second marking machine 96, calibration sheet 100, first spectral confocal displacement sensor 101, second spectral confocal displacement sensor 102, camera 160, and lighting device 161. Specific embodiments

[0127] Hereinafter, embodiments of the technical solution of the present invention 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 invention, and thus are only examples and should not be used to limit the protection scope of the present invention.

[0128] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs; the terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the terms "comprising" and "having" and any variations thereof in the specification and claims of the present invention and the above description of the drawings are intended to cover non-exclusive inclusion.

[0129] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0130] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0131] In the description of the embodiments of the present invention, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0132] In the description of the embodiments of the present invention, the term "a plurality of" refers to more than two (including two). Similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0133] In the description of the embodiments of the present invention, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0134] In the description of the embodiments of the present invention, unless otherwise clearly specified and defined, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0135] Currently, from the perspective of the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of batteries, the market demand is also continuously increasing.

[0136] The existing coating production process is to evenly coat a layer of slurry on the electrode sheet. After a series of operations such as rolling, die-cutting, winding, and compaction are performed on the coated sheet to form an electrode core, coating peeling may occur at the corners, causing lithium plating on the electrode core and resulting in safety accidents. Therefore, in order to overcome the above defects, a new coating process has been proposed in the related art. The new coating process is as Figure 1 shown. Figure 1 is a side view of the electrode sheet in the new coating process. Figure 1 In, the positive electrode material is coated on both sides of the foil 12 to form a film area 11. When coating the positive electrode material on one side, a dual die head is used. The first die head evenly coats a layer (i.e., the first coating 13), and the second die head coats another layer (i.e., the second coating 14) at intervals (coating gap length) on the basis of the first coating, so that the corner of the formed electrode core is a thickness-thinned area 10. The gap coating is as Figure 2 shown. Figure 2 is a top view of the electrode sheet in the new coating process. Figure 2 In, the electrode sheet after gap coating includes a thickness-thinned area 10, a film area 11, and an ear area 20.

[0137] Before the electrode sheet after gap coating is wound into an electrode core, it also needs to go through rolling and die-cutting. Rolling is to compact and slit the electrode sheet after gap coating. The electrode sheet after rolling and slitting is as Figure 3 shown. Figure 3 is a top view of the electrode sheet in the new coating process. Die-cutting is to cut the ears and slit the electrode sheet after rolling. The electrode sheet after die-cutting and slitting is as Figure 4 shown. Figure 4 is a top view of the electrode sheet in the new coating process, asFigure 4 As shown, in the winding stage, in order to make the thickness reduction area at the corner of the battery cell winding, it is necessary to accurately cut the first pole ear 40 at the designed spacing before the thickness reduction area 10 in the die-cutting process. Therefore, how to accurately cut the first pole ear at the designed spacing before the thickness reduction area in the die-cutting process is a technical problem to be solved urgently.

[0138] In order to solve the problem of how to accurately cut the first pole ear at the designed spacing before the thickness thinning zone in the die-cutting process, the starting point of the thickness thinning zone can be determined by measuring the change in the pole piece thickness data, and the laser can be guided to cut the first pole ear according to the starting point of the thickness thinning zone, so that the position of the thickness thinning zone can be accurately identified in the die-cutting process, and then the first pole ear can be accurately cut at the designed spacing before the thickness thinning zone in the die-cutting process, so that the thickness thinning zone is at the corner of the battery cell winding.

[0139] In some embodiments, a die-cutting system is proposed, which includes: a sensor, a controller and a laser; the sensor is used to collect pole piece thickness data of the pole piece, and send the pole piece thickness data to the controller; the controller is used to determine the starting point of the thickness thinning zone according to the change of the pole piece thickness data, calculate the first distance from the starting point of the thickness thinning zone to the laser, calculate the die-cutting waiting time according to the first distance, and send the die-cutting waiting time to the laser; the laser is used to die-cut the pole piece after the die-cutting waiting time to obtain the first pole ear.

[0140] In order to make the thickness reduction zone at the corner of the battery cell winding, it is necessary to accurately cut the first pole ear at the designed spacing before the thickness reduction zone in the die-cutting process. Therefore, it is necessary to accurately identify the position of the thickness reduction zone in the die-cutting process, and guide the laser to cut the first pole ear according to the position of the thickness reduction zone. In order to accurately identify the position of the thickness reduction zone in the die-cutting process, in this embodiment, the pole piece thickness data of the pole piece is collected by a sensor, and the starting point of the thickness reduction zone is determined according to the change of the pole piece thickness data. In order to accurately cut the first pole ear at the designed spacing before the thickness reduction zone, in this embodiment, the first distance from the starting point of the thickness reduction zone to the laser is first calculated, the die-cutting waiting time is calculated according to the first distance, and the laser is controlled. After the die-cutting waiting time, the pole piece is die-cut to obtain the first pole ear.

[0141] For ease of understanding, refer to Figure 5 This invention is provided for illustration, but is not intended to limit the present application. Figure 5 Schematic diagram of die-cutting system in some embodiments of the present invention, as an example, Figure 5 In the figure, it is assumed that the design spacing between the starting point of the thickness thinning area and the midpoint of the first pole ear is L, and the pole piece running direction is shown by the arrow in the figure. Figure 5In this case, the die-cutting system includes a sensor 50, a controller, and a laser 51. When the pole piece is running, the sensor 50 collects the pole piece thickness data of the pole piece by emitting detection light, and sends the pole piece thickness data to the controller. Among them, the sensor 50 can be a point laser thickness gauge or a spectral confocal displacement sensor, and this embodiment does not limit this. After receiving the pole piece thickness data, the controller determines the starting point of the thickness thinning area by analyzing the change of the pole piece thickness data (for example, the first drop point when the pole piece thickness data continuously drops can be determined as the starting point of the thickness thinning area). After determining the starting point of the thickness thinning area, the first distance L1 from the starting point of the thickness thinning area to the laser 51 is obtained. After obtaining the first distance L1 from the starting point of the thickness thinning area to the laser 51, the die-cutting waiting time T of the laser 51 can be calculated according to the running speed V of the pole piece (assuming the pole piece is running at a constant speed) and the designed distance L between the starting point of the thickness thinning area and the midpoint of the first pole ear. The specific calculation formula is T = (L1 - L) / V. After obtaining the die-cutting waiting time T, the controller sends the die-cutting waiting time T to the laser 51. After an interval of the die-cutting waiting time, the laser 51 die-cuts the pole ear area 20 of the pole piece to obtain the first pole ear 40.

[0142] In this embodiment, by measuring the change of the pole piece thickness data to determine the starting point of the thickness thinning area, and guiding the laser to cut the first pole ear according to the starting point of the thickness thinning area, it is possible to accurately identify the position of the thickness thinning area in the die-cutting process, and then accurately cut the first pole ear at the designed distance in front of the thickness thinning area in the die-cutting process, so that the thickness thinning area is at the corner of the battery core winding.

[0143] In some embodiments, the die-cutting system further includes: an encoder, an image collector, and a coding roller corresponding to the encoder; when the pole piece is running, the coding roller is driven to rotate, and the rotation of the coding roller drives the encoder to trigger a pulse; the sensor is used to collect the pole piece thickness data of the pole piece in response to the pulse and send the pole piece thickness data to the controller; the image collector is used to collect the image of the pole piece after die-cutting in response to the pulse and send the image of the pole piece after die-cutting to the controller; the controller is used to perform defect detection on the pole piece after die-cutting according to the image of the pole piece after die-cutting.

[0144] In order to achieve the consistency between the pole piece running and the pole piece detection, in this embodiment, a pulse is triggered when the pole piece is running, and in response to the pulse, the pole piece thickness data of the pole piece and the image of the pole piece after die-cutting are collected. For the sake of understanding, reference Figure 6 is made for illustration, but it does not limit the present application. Figure 6 This is a running belt schematic diagram of the die-cutting system according to some embodiments of the present invention. As an example, Figure 6In this case, it is assumed that the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab is L, and the running direction of the pole piece is as shown by the arrow in the figure. Figure 6 In this case, the die-cutting system includes a guiding roller 60, a sensor 50, a controller, a laser 51, an encoder 61, an image collector 63, and a coding roller 62 corresponding to the encoder 61. The guiding roller 60 drives the running of the pole piece. The running of the pole piece drives the coding roller 62 to rotate. The rotation of the coding roller 62 drives the encoder 61 to trigger a pulse. The sensor 50 responds to the pulse, collects the pole piece thickness data of the pole piece by emitting a detection light beam, and sends the pole piece thickness data to the controller. After receiving the pole piece thickness data, the controller determines the starting point of the thickness thinning area by analyzing the change of the pole piece thickness data (for example, the first falling point when the pole piece thickness data continuously decreases can be determined as the starting point of the thickness thinning area). After determining the starting point of the thickness thinning area, the controller further obtains the first distance L1 from the starting point of the thickness thinning area to the laser 51. After obtaining the first distance L1 from the starting point of the thickness thinning area to the laser 51, the die-cutting waiting time T of the laser 51 can be calculated according to the running speed V of the pole piece (assuming the pole piece runs at a constant speed) and the designed distance L between the starting point of the thickness thinning area and the midpoint of the first tab. The specific calculation formula is T = (L1 - L) / V. After obtaining the die-cutting waiting time T, the controller sends the die-cutting waiting time T to the laser 51. After an interval of the die-cutting waiting time, the laser 51 performs die-cutting on the pole piece to obtain the first tab. The image collector 63 responds to the pulse, collects the image of the pole piece after die-cutting, and sends the image of the pole piece after die-cutting to the controller. Among them, the image collector 63 can be a camera. The image collector 63 can be set at multiple positions to detect various defects. For example, it can detect conventional defects such as metal leakage, tab residue, and straight-edge residue. Of course, the image collector 63 can also be set near the laser 51 to detect whether the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is equal to the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab. The specific setting method can be as Figure 7 shown, and this embodiment does not limit this. After receiving the image of the pole piece after die-cutting, the controller performs defect detection on the pole piece after die-cutting according to the image of the pole piece after die-cutting.

[0145] In this embodiment, a pulse is triggered during the running of the pole piece. In response to the pulse, the pole piece thickness data of the pole piece and the image of the pole piece after die-cutting are collected, so as to achieve the consistency between the running of the pole piece and the pole piece detection, and further improve the accuracy of the pole piece detection.

[0146] In some embodiments, the die-cutting waiting time is the number of die-cutting waiting pulses; the controller is further configured to obtain the encoder accuracy of the encoder, calculate the number of die-cutting waiting pulses according to the pulse accuracy and the first distance, and send the number of die-cutting waiting pulses to the laser; the laser is further configured to perform die-cutting on the pole piece after an interval of the number of die-cutting waiting pulses to obtain a first tab.

[0147] Considering that the pole piece tape running speed is not uniform in some cases, if the laser is still controlled to die-cut the first tab according to the die-cutting waiting time at this time, it may cause the position of the first tab to be inaccurate. Therefore, in this embodiment, the number of die-cutting waiting pulses is calculated according to the encoder accuracy, and after an interval of the number of die-cutting waiting pulses, the laser is controlled to perform die-cutting on the pole piece to obtain a first tab.

[0148] For ease of understanding, the following is an example, but it does not limit the present application. As an example, assume that the designed distance between the starting point of the thickness-thinned area and the midpoint of the first tab is L, and the main working steps of the gap die-cutting detection system include:

[0149] 1. Collect the pole piece thickness data of the pole piece.

[0150] 2. Determine the starting point of the thickness-thinned area according to the change of the pole piece thickness data.

[0151] 3. Calculate the first distance L1 from the starting point of the thickness-thinned area to the laser.

[0152] 4. Calculate the number of die-cutting waiting pulses X = (L1 - L) / P according to the first distance L1 from the starting point of the thickness-thinned area to the laser, the designed distance L between the starting point of the thickness-thinned area and the midpoint of the first tab, and the encoder accuracy P. The laser starts to cut the first tab after waiting for X pulses, where the encoder accuracy P represents the number of pulses generated by the encoder per revolution.

[0153] 5. The camera takes a picture of the pole piece after laser die-cutting. In addition to calculating the conventional pole piece defects and dimensions, it can also detect whether the actual distance between the starting point of the thickness-thinned area and the midpoint of the first tab is equal to the designed distance between the starting point of the thickness-thinned area and the midpoint of the first tab.

[0154] In this embodiment, the number of die-cutting waiting pulses is calculated according to the encoder accuracy, and after an interval of the number of die-cutting waiting pulses, the laser is controlled to perform die-cutting on the pole piece to obtain a first tab, so as to reduce the influence of the pole piece tape running speed on the laser die-cutting of the first tab, and further improve the accuracy of the first tab die-cutting.

[0155] In some embodiments, the controller is further configured to obtain the die-cutting error of the first tab according to the image of the die-cut pole piece; if the die-cutting error is not within a preset error range, generate an error correction instruction according to the die-cutting error; the laser is further configured to, after the die-cutting waiting time, perform die-cutting on the pole piece according to the error correction instruction to obtain the next first tab.

[0156] In order to correct the error in the process of the laser die-cutting the first tab in a timely manner, in this embodiment, the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is obtained through the image of the die-cut pole piece, and the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab is obtained. The laser is controlled according to whether the die-cutting error between the actual distance and the designed distance is within a preset error range, thereby forming a complete closed-loop detection system.

[0157] For ease of understanding, the following is an example, but it does not limit the present application. As an example, assume that the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab is L. The main working steps of the gap die-cutting detection system include:

[0158] 1. Collect the pole piece thickness data of the pole piece.

[0159] 2. Determine the starting point of the thickness thinning area according to the change of the pole piece thickness data.

[0160] 3. Calculate the first distance L1 from the starting point of the thickness thinning area to the laser.

[0161] 4. Calculate the die-cutting waiting pulse number X = (L1 - L) / P according to the first distance L1 from the starting point of the thickness thinning area to the laser, the designed distance L between the starting point of the thickness thinning area and the midpoint of the first tab, and the encoder accuracy P. The laser starts to cut the first tab after waiting for X pulses. Here, the encoder accuracy P represents the number of pulses generated by the encoder per revolution.

[0162] 5. The camera takes a picture of the pole piece after laser die-cutting. In addition to calculating the conventional pole piece defects and dimensions, it can also detect whether the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is equal to the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab.

[0163] 6. Obtain the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab, and calculate the distance error between the actual distance and the designed distance; if the distance error is within a preset error range, return to step 1 and continue to die-cut the next first tab. Here, the preset error range can be an error range preset according to the specification requirements, and this embodiment does not limit this.

[0164] 7. If the spacing error is not within the preset error range, a closed-loop control is performed with the laser. Specifically, it can be: the controller generates an error correction instruction based on the spacing error and sends the error correction instruction to the laser; after the laser waits for X pulses, it performs die-cutting on the pole piece according to the error correction instruction to obtain the next first tab.

[0165] In this embodiment, the die-cutting error of the first tab is obtained through the image of the pole piece after die-cutting. If the die-cutting error is not within the preset error range, an error correction instruction is generated based on the die-cutting error to control the laser, thereby forming a complete closed-loop detection system, and then being able to correct errors in the process of the laser die-cutting the first tab in a timely manner, improving the reliability of the die-cutting system.

[0166] In some embodiments, the controller is further configured to obtain a second distance from the sensor to the laser, and obtain the running distance of the pole piece when the sensor collects the pole piece thickness data; calculate a first distance from the starting point of the thickness thinning area to the laser according to the second distance and the running distance.

[0167] To improve the accuracy of the first distance, in this embodiment, when calculating the first distance, the second distance from the sensor to the laser and the running distance of the pole piece when the sensor collects the pole piece thickness data are also considered.

[0168] For ease of understanding, reference is made to Figure 6 and Figure 7 for illustration, but the present application is not limited thereto. As an example, assume that the designed spacing between the starting point of the thickness thinning area and the midpoint of the first tab is L, and the running direction of the pole piece is as shown by the arrow in the figure. The die-cutting system includes a tension roller 60, a sensor 50, a controller, a laser 51, an encoder 61, an image collector 63, and a coding roller 62 corresponding to the encoder 61. The main working steps of the gap die-cutting detection system include:

[0169] 1. The tension roller 60 drives the pole piece to run. The running of the pole piece drives the coding roller 62 to rotate. The rotation of the coding roller 62 drives the encoder 61 to trigger a pulse. After the sensor 50 receives the pulse trigger, it collects the pole piece thickness data at this time, and 5000 data are taken as a group (which can be preset in advance).

[0170] 2. For the collected data, first preliminarily determine whether the data is an inflection point. The judgment logic is that the collected data is compared with the preset data. The preset data is the value obtained by adding the thickness of the pole piece in the thickness thinning area and the thickness of the pole piece in the non-thickness thinning area and dividing by 2. If the collected data is less than the preset value and the subsequent 500 points (which can be set) are continuously less than this value, then this point is a descending mutation point; similarly, if the collected data is greater than the preset value and the subsequent 500 points (which can be set) are continuously greater than this value, then this point is an ascending mutation point.

[0171] 3. Based on the found mutation point positions, smooth the 500 data points before and after the mutation points, then calculate the derivative to find the inflection points of the thickness thinning area.

[0172] 4. Assume that the first inflection point (i.e., the starting point of the thickness thinning area) of the thickness thinning area is the Mth point in the Nth group of arrays. After the data acquisition of the (N + 1)th group is completed, calculate the first distance L1 from the starting point of the thickness thinning area to the laser 51 through the following formula:

[0173] L1 = L2 - (2 * 5000 - M) * P * m / d

[0174] In the formula, L1 represents the distance from the starting point of the thickness thinning area to the laser 51, L2 represents the distance between the sensor 50 and the laser 51, (2 * 5000 - M) * P * m / d represents the tape running distance of the pole piece when the sensor acquires the pole piece thickness data, (2 * 5000 - M) represents the number of interval data points between the starting point of the thickness thinning area and the end point of this data acquisition, P represents the encoder 61 accuracy, m represents the frequency division of the sensor 50, and d represents the frequency division of the sensor 50.

[0175] 5. Calculate the die-cutting waiting pulse number X = (L1 - L) / P according to the first distance L1 from the starting point of the thickness thinning area to the laser 51, the designed distance L between the starting point of the thickness thinning area and the midpoint of the first tab, and the encoder 61 accuracy P. The laser 51 starts to cut the first tab after waiting for X pulses.

[0176] 6. The image collector 63 acquires pictures of the gap pole piece and the tab, calculates the position from the first inflection point of the thickness thinning area to the tab according to the pictures, finds the tab contour according to the threshold, and then calculates the center position of the tab. According to the pictures, the position of the edge of the thickness thinning area is calculated, and then the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is calculated.

[0177] 7. Obtain the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab, calculate the distance error between the actual distance and the designed distance. If the distance error is not within the preset error range, generate an error correction instruction according to the distance error and the requirements of the actual process, and send the error correction instruction to the laser 51. The laser 51 then die-cuts the next first tab and compensates the cutting distance of the laser 51 for the first tab according to the error correction instruction.

[0178] In this embodiment, when calculating the first distance, the second distance from the sensor to the laser and the tape running distance of the pole piece when the sensor acquires the pole piece thickness data are also considered, so as to improve the accuracy of the first distance calculation, and further improve the accuracy of the first tab die-cutting.

[0179] In some embodiments, the sensor, the laser, the coding roller, and the image collector are sequentially arranged in the running direction of the pole piece. The data acquisition direction of the sensor is perpendicular to the running direction of the pole piece. The light outlet of the laser is perpendicular to the running direction of the pole piece. The image acquisition direction of the image collector is perpendicular to the running direction of the pole piece.

[0180] To improve the accuracy of data acquisition and laser die-cutting, in this embodiment, the sensor, the laser, the coding roller, and the image collector are sequentially arranged in the running direction of the pole piece, and the directions of data acquisition and laser die-cutting are set perpendicular to the running direction of the pole piece. For the sake of understanding, reference is made to Figure 6 for illustration, but this does not limit the present application. Figure 6 FIG. is a schematic diagram of the running of the die-cutting system according to some embodiments of the present invention. As an example, Figure 6 in FIG., the running direction of the pole piece is as shown by the arrow in the figure. The die-cutting system includes a roller 60, a sensor 50, a controller, a laser 51, an encoder 61, an image collector 63, and a coding roller 62 corresponding to the encoder 61. The sensor 50, the laser 51, the coding roller 62, and the image collector 63 are sequentially arranged in the running direction of the pole piece. Among them, the sensor 50 is at the front to locate the thickness-thinned area, and then transmits the position of the thickness-thinned area to the controller. The controller controls the laser 51 to cut the tab at a fixed position from the thickness-thinned area on the pole piece. The data acquisition direction of the sensor 50 is perpendicular to the running direction of the pole piece. The light outlet of the laser 51 is perpendicular to the running direction of the pole piece. The image acquisition direction of the image collector 63 is perpendicular to the running direction of the pole piece. In a specific implementation, the shooting point of the image collector 63 can be located 3 mm from the cutting point of the pole piece. This embodiment does not limit this.

[0181] In this embodiment, the sensor, the laser, the coding roller, and the image collector are sequentially arranged in the running direction of the pole piece, and the directions of data acquisition and laser die-cutting are set perpendicular to the running direction of the pole piece, thereby improving the accuracy of data acquisition and laser die-cutting.

[0182] In some embodiments, the sensor includes a first sensor and a second sensor. The first sensor and the second sensor are arranged on both sides of the pole piece in a opposed form. The data acquisition directions of the first sensor and the second sensor are perpendicular to the pole piece.

[0183] To improve the accuracy of the pole piece thickness data, in this embodiment, a first sensor and a second sensor can be respectively arranged on both sides of the pole piece. The first sensor and the second sensor acquire the pole piece thickness data of the pole piece in an opposed form.

[0184] For the sake of understanding, reference is made to Figure 8A description is given, but the present application is not limited thereby. Figure 8 FIG. 418 is a schematic diagram of the web running of the die-cutting system according to some embodiments of the present invention. As an example, Figure 8 in FIG. 419, the running direction of the pole piece is as shown by the arrow in the figure. The die-cutting system includes a guide roller 60, a first sensor 80, a second sensor 81, a controller, a laser 51, an encoder 61, an image collector 63, and a coding roller 62 corresponding to the encoder 61. The first sensor 80 and the second sensor 81 are arranged on both sides of the pole piece in a transmissive form. The data acquisition directions of the first sensor 80 and the second sensor 81 are perpendicular to the pole piece.

[0185] In this embodiment, the first sensor and the second sensor are respectively arranged on both sides of the pole piece. The first sensor and the second sensor collect the pole piece thickness data of the pole piece in a transmissive form, so as to improve the accuracy of the pole piece thickness data.

[0186] In some embodiments, the image collector includes a first image collector, a second image collector, a third image collector, and a fourth image collector; the first image collector is used to detect the front defects of the die-cut pole piece; the second image collector is used to detect the backlight defects of the die-cut pole piece; the third image collector and the fourth image collector are used to detect the back defects of the die-cut pole piece.

[0187] In order to improve the comprehensiveness and accuracy of pole piece defect detection, in this embodiment, a plurality of image collectors can be arranged at multiple positions to detect the defects of the pole piece.

[0188] For the sake of easy understanding, reference is made to Figure 9 A description is given, but the present application is not limited thereby. Figure 9 FIG. 429 is a schematic diagram of the web running of the die-cutting system according to some embodiments of the present invention. As an example, Figure 9Among them, the running direction of the pole piece is as shown by the arrow in the figure. The die-cutting system includes a guiding roller 60, a first sensor 80, a second sensor 81, a controller, a laser 51, an encoder 61, a coding roller 62 corresponding to the encoder 61, a first image collector 91, a second image collector 92, a third image collector 93, and a fourth image collector 94. Among them, the first image collector 91 can be used to detect defects on the front side of the pole piece, such as metal leakage, pole piece wrinkles, and straight-edge breakage, and measure the size of the film area, etc. The second image collector 92 can be a backlight camera. Through the backlight lighting method, defects such as pole piece breakage, tab scraps, and straight-edge scraps can be detected. The third image collector 93 and the fourth image collector 94 detect defects on the back side of the pole piece, and the detection items can be the same as those of the first image collector 91. Of course, in this embodiment, the die-cutting system may further include a first marking machine 95 and a second marking machine 96. The first marking machine 95 and the second marking machine 96 are used to mark the pole piece. For example, if a gap trailing is detected on the pole piece, defect marking needs to be performed on the pole piece by the first marking machine 95 and / or the second marking machine 96.

[0189] In this embodiment, multiple image collectors are arranged at multiple positions to detect the defects of the pole piece, so as to improve the comprehensiveness and accuracy of the pole piece defect detection.

[0190] In some embodiments, the first image collector includes a first camera and a first light source, and the first camera and the first light source are arranged on the same side of the pole piece; the second image collector includes a second camera and a second light source, and the second camera and the second light source are respectively arranged on both sides of the pole piece; the third image collector includes a third camera and a third light source, and the third camera and the third light source are arranged on the same side of the pole piece; the fourth image collector includes a fourth camera and a fourth light source, and the fourth camera and the fourth light source are arranged on the same side of the pole piece.

[0191] In order to improve the image acquisition effect of the image collector, in this embodiment, the first image collector, the third image collector, and the fourth image collector adopt coaxial light, that is, the camera and the light source are arranged on the same side of the pole piece, perpendicular to the pole piece, and the shooting point is 3 mm away from the pole piece cutting point. The second image collector adopts the backlight lighting method, that is, the camera and the light source are respectively arranged on both sides of the pole piece, perpendicular to the pole piece.

[0192] In some embodiments, the controller is further configured to obtain the inflection point coordinates of the thickness thinning area and the starting point coordinates of each pole piece strip, where the pole piece strip is the strip corresponding to the pole piece of one cell length; calculate the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the starting point coordinates of each pole piece strip.

[0193] In order to accurately calculate the length of the thickness thinning area and the length of each pole piece strip, in this embodiment, the length of the thickness thinning area is calculated according to the inflection point coordinates of the thickness thinning area, and the length of each pole piece strip is calculated according to the starting point coordinates of each pole piece strip.

[0194] For ease of understanding, reference is made to Figure 10 for illustration, but this does not limit the present application. Figure 10 FIG. is a schematic diagram of the thickness of the thickness thinning area in some embodiments of the present invention. As an example, after obtaining the abscissas of four points A, B, C, and D, the lengths of three regions AB, BC, and CD can be directly calculated according to the abscissas of the four points A, B, C, and D, and then the length of the thickness thinning area can be calculated based on the lengths of the three regions AB, BC, and CD; similarly, the length of each pole piece strip can be calculated according to the starting point coordinates of each pole piece strip.

[0195] In this embodiment, the length of the thickness thinning area is calculated according to the inflection point coordinates of the thickness thinning area, and the length of each pole piece strip is calculated according to the starting point coordinates of each pole piece strip, so that the length of the thickness thinning area and the length of each pole piece strip can be accurately calculated.

[0196] In some embodiments, the die-cutting system further includes: a calibration ruler, the calibration ruler is arranged on the coding roller; the calibration ruler is rotated by the rotation of the coding roller, and the rotation of the coding roller drives the encoder to trigger a calibration pulse; the image collector is further configured to collect a calibration image of the calibration ruler in response to the calibration pulse and send the calibration image to the controller; the controller is further configured to obtain the calibration ruler parameters of the calibration ruler, calculate the calibration accuracy according to the calibration image and the calibration ruler parameters, where the calibration accuracy is used to represent the mapping relationship between the pixel distance and the actual distance; calculate the length of the thickness thinning area according to the calibration accuracy and the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the calibration accuracy and the starting point coordinates of each pole piece strip.

[0197] In order to further improve the accuracy of the length of the thickness thinning area and the length of each pole piece strip, in this embodiment, the target calibration accuracy can be determined first, and then the length of the coating gap area is calculated according to the target calibration accuracy and the inflection point coordinates of the coating gap area, and the length of each pole piece strip is calculated according to the target calibration accuracy and the starting point coordinates of each pole piece strip.

[0198] In specific implementation, the sensor can be indirectly calibrated by calibrating the image collector. For ease of understanding, reference is made to Figure 11 and Figure 12 for illustration, but this does not limit the present application. Figure 11 FIG. is a schematic diagram of the calibration ruler in some embodiments of the present invention, Figure 12Schematic diagram of a calibration image for some embodiments of the present invention. The calibration method of this embodiment requires the use of Figure 11 the shown film ruler. The film ruler is made of white non-transparent soft film material, and the pattern consists of black and white rectangles with a size of 15 mm. This calibration method uses an encoder to trigger an image collector (such as a camera) to collect pictures of the film ruler. According to the collected pictures, as Figure 11 shown, calculate the longitudinal resolution of the picture, and then obtain the pulse accuracy of the encoder. Then calculate the target calibration accuracy of the sensor (such as a spectral confocal displacement sensor) in the tape running direction. The specific steps are as follows:

[0199] 1. Stick the calibration ruler with black and white intervals on the roller, and the encoder triggers image acquisition.

[0200] 2. The camera collects S complete black and white grids, and the algorithm measures the number of rows K occupied by the S black and white grids.

[0201] 3. The first calibration accuracy P1 of the camera in the tape running direction = S * 15 / K.

[0202] 4. The second calibration accuracy P2 of the encoder in the tape running direction = P / camera multiplication factor.

[0203] 5. The target calibration accuracy P3 of the spectral confocal position in the tape running direction = P2 * point spectral multiplication factor.

[0204] In this embodiment, by calibrating the image collector, the sensor is indirectly calibrated, so that the target calibration accuracy can be determined, and the accuracy of calculating the length of the thickness thinning area and the length of each pole piece tape in the subsequent process can be improved.

[0205] In some embodiments, the sensor is a spectral confocal displacement sensor, and the spectral confocal displacement sensor includes: a point light source, a dispersion confocal probe, a beam splitting component, and a detector; the point light source is used to emit detection light to the pole piece, and the detection light forms detection light with different wavelengths after passing through the dispersion confocal probe. Among them, when the detection light with different wavelengths irradiates the pole piece, the return light of the pole piece is connected to the detector through the beam splitting component, and the beam splitting component is used to block the light with unfocused wavelengths in the return light; the detector is used to obtain the light wavelength of the return light and look up the pole piece thickness data corresponding to the light wavelength in a preset wavelength relationship table, where the preset wavelength relationship table includes the corresponding relationship between the light wavelength and the pole piece thickness data; and send the pole piece thickness data to the controller.

[0206] For ease of understanding, the following is an example, but it does not limit the present application. As an example, assume that the instrument for thickness measurement is a spectral confocal displacement sensor, and its measurement principle is as follows: A white point light source forms a conical dispersion light source after passing through a dispersion confocal probe. The dispersion angles of lights with different wavelengths are different, and lights with different wavelengths are confocal at different positions. When the light source irradiates an object at different heights, the light spot on the object returns through a coaxial optical path, passes through a small aperture diaphragm, and is connected to a spectrometer. The light rays with unfocused wavelengths are blocked and attenuated by the diaphragm (i.e., the spectral splitting component) after returning, and the wavelengths of the light rays received by the spectrometer (i.e., the detector) can reflect the height information of the object. When the distance from the target changes, the wavelength of the focused light also changes, resulting in different spectral distributions in the spectrometer. Compared with point laser thickness measurement, the spectral confocal displacement sensor is small in volume, has a small measurement blind area, and has strong anti-interference ability.

[0207] For ease of understanding, reference is made to Figure 13 for illustration, but it does not limit the present application. Figure 13 FIG. is a schematic diagram of thickness measurement by the spectral confocal displacement sensor for some embodiments of the present invention. Figure 13 In it, the measurement steps are as follows:

[0208] 1. Adjust the first spectral confocal displacement sensor 101 and the second spectral confocal displacement sensor 102 to be confocal.

[0209] 2. Use a calibration sheet 100 with a thickness of 0.5 mm for calibration, and the purpose is to obtain the distance H between the first spectral confocal displacement sensor 101 and the second spectral confocal displacement sensor 102.

[0210] 3. Calculate the thickness of the object to be measured according to the following formula:

[0211] h = H - A - B

[0212] In the formula, H represents the distance between the first spectral confocal displacement sensor 101 and the second spectral confocal displacement sensor 102, A represents the distance from the upper sensor to the object to be measured, B represents the distance from the lower sensor to the object to be measured, and h represents the thickness of the object to be measured.

[0213] In this embodiment, the sensor is set as a spectral confocal displacement sensor, so that the volume of the sensor can be reduced, the measurement blind area can be reduced, and the anti-interference ability can be improved.

[0214] In some embodiments, as Figure 14 shown, a die-cutting method is proposed, including:

[0215] Step S10: Collect the pole piece thickness data of the pole piece.

[0216] Step S20: Determine the starting point of the thickness thinning area according to the change of the pole piece thickness data, calculate the first distance from the starting point of the thickness thinning area to the die-cutting position of the pole piece, and calculate the die-cutting waiting time according to the first distance.

[0217] Step S30: After the die-cutting waiting time has elapsed, perform die-cutting on the pole piece at the die-cutting position of the pole piece to obtain the first pole ear.

[0218] In this embodiment, the die-cutting method can be applied to a die-cutting system, and the die-cutting system includes a sensor, a controller, and a laser. In order to make the gap coating area at the corner of the battery cell winding, it is necessary to accurately cut the first pole ear at the designed distance in front of the thickness thinning area during the die-cutting process. Therefore, it is necessary to accurately identify the position of the thickness thinning area during the die-cutting process and guide the laser to cut the first pole ear according to the position of the thickness thinning area. In order to accurately identify the position of the thickness thinning area during the die-cutting process, in this embodiment, the pole piece thickness data of the pole piece is collected by a sensor, and the starting point of the thickness thinning area is determined according to the change of the pole piece thickness data. In order to accurately cut the first pole ear at the designed distance in front of the thickness thinning area, in this embodiment, the first distance from the starting point of the thickness thinning area to the laser is first calculated, the die-cutting waiting time is calculated according to the first distance, and the laser is controlled. After the die-cutting waiting time has elapsed, the pole piece is die-cut to obtain the first pole ear.

[0219] For ease of understanding, reference is made to Figure 5 for illustration, but it does not limit the present application. Figure 5 FIG. is a schematic diagram of a die-cutting system according to some embodiments of the present invention. As an example, Figure 5 in which it is assumed that the designed distance between the starting point of the thickness thinning area and the midpoint of the first pole ear is L, and the pole piece running direction is as shown by the arrow in the figure. Figure 5In this case, the die-cutting system includes a sensor 50, a controller, and a laser 51. When the pole piece is running, the sensor 50 collects the pole piece thickness data of the pole piece by emitting detection light, and sends the pole piece thickness data to the controller. Among them, the sensor 50 can be a point laser thickness gauge or a spectral confocal displacement sensor, and this embodiment does not limit this. After receiving the pole piece thickness data, the controller determines the starting point of the thickness thinning area by analyzing the change of the pole piece thickness data (for example, the first drop point when the pole piece thickness data continuously drops can be determined as the starting point of the thickness thinning area). After determining the starting point of the thickness thinning area, the first distance L1 from the starting point of the thickness thinning area to the laser 51 is obtained. After obtaining the first distance L1 from the starting point of the thickness thinning area to the laser 51, the die-cutting waiting time T of the laser 51 can be calculated according to the running speed V of the pole piece (assuming the pole piece runs at a constant speed) and the designed distance L between the starting point of the thickness thinning area and the midpoint of the first pole ear. The specific calculation formula is T = (L1 - L) / V. After obtaining the die-cutting waiting time T, the controller sends the die-cutting waiting time T to the laser 51. After an interval of the die-cutting waiting time, the laser 51 die-cuts the pole ear area 20 of the pole piece to obtain the first pole ear 40.

[0220] In this embodiment, by measuring the change of the pole piece thickness data to determine the starting point of the thickness thinning area, and guiding the laser to cut the first pole ear according to the starting point of the thickness thinning area, it is possible to accurately identify the position of the thickness thinning area in the die-cutting process, and further accurately cut the first pole ear at the designed distance in front of the thickness thinning area in the die-cutting process, so that the thickness thinning area is at the corner of the core winding.

[0221] In some embodiments, as Figure 15 shown, before the step S10, it further includes:

[0222] Step S01: Trigger a pulse when the pole piece is running.

[0223] Correspondingly, the step S10 includes:

[0224] Step S10': In response to the pulse, collect the pole piece thickness data of the pole piece.

[0225] After the step S30, it further includes:

[0226] Step S40: In response to the pulse, collect the image of the pole piece after die-cutting, and perform defect detection on the pole piece after die-cutting according to the image of the pole piece after die-cutting.

[0227] In order to achieve the consistency between the pole piece running and the pole piece detection, in this embodiment, a pulse is triggered when the pole piece is running, and in response to the pulse, the pole piece thickness data of the pole piece and the image of the pole piece after die-cutting are collected. For the convenience of understanding, refer to Figure 6This is for illustration purposes only and does not limit the present application. Figure 6 It is a schematic diagram of the tape running of the die-cutting system according to some embodiments of the present invention. As an example, Figure 6 In it, assuming that the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab is L, and the tape running direction of the pole piece is as shown by the arrow in the figure. Figure 6 In it, the die-cutting system includes a roller 60, a sensor 50, a controller, a laser 51, an encoder 61, an image collector 63, and a coding roller 62 corresponding to the encoder 61. The roller 60 drives the pole piece to run the tape, the running tape of the pole piece drives the coding roller 62 to rotate, the rotation of the coding roller 62 drives the encoder 61 to trigger a pulse. The sensor 50 responds to the pulse, collects the pole piece thickness data of the pole piece by emitting a detection light, and sends the pole piece thickness data to the controller. After receiving the pole piece thickness data, the controller determines the starting point of the thickness thinning area by analyzing the change of the pole piece thickness data (for example, the first dropping point when the pole piece thickness data continuously drops can be determined as the starting point of the thickness thinning area). After determining the starting point of the thickness thinning area, then obtain the first distance L1 from the starting point of the thickness thinning area to the laser 51. After obtaining the first distance L1 from the starting point of the thickness thinning area to the laser 51, the die-cutting waiting time T of the laser 51 can be calculated according to the running speed V of the pole piece (assuming the pole piece runs at a constant speed) and the designed distance L between the starting point of the thickness thinning area and the midpoint of the first tab. The specific calculation formula is T = (L1 - L) / V. After obtaining the die-cutting waiting time T, the controller sends the die-cutting waiting time T to the laser 51. After an interval of the die-cutting waiting time, the laser 51 performs die-cutting on the pole piece to obtain the first tab. The image collector 63 responds to the pulse, collects the image of the pole piece after die-cutting, and sends the image of the pole piece after die-cutting to the controller. Among them, the image collector 63 can be a camera, and the image collector 63 can be set at multiple positions to detect various defects. For example, detect conventional defects such as metal leakage, tab residue, straight edge residue, etc. Of course, the image collector 63 can also be set near the laser 51 to detect whether the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is equal to the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab. The specific setting method can be as Figure 7 shown, and this embodiment does not limit this. After receiving the image of the pole piece after die-cutting, the controller performs defect detection on the pole piece after die-cutting according to the image of the pole piece after die-cutting.

[0228] In this embodiment, a pulse is triggered when the pole piece runs the tape, and in response to the pulse, the pole piece thickness data of the pole piece and the image of the pole piece after die-cutting are collected, so as to achieve the consistency of the pole piece running the tape and the pole piece detection, and further improve the accuracy of the pole piece detection.

[0229] In some embodiments, the die-cutting waiting time is the die-cutting waiting pulse number; as Figure 16As shown, the step S20 includes:

[0230] Step S201: Determine the starting point of the thickness thinning area according to the change of the pole piece thickness data, and calculate the first distance from the starting point of the thickness thinning area to the die-cutting position of the pole piece.

[0231] Step S202: Obtain the pulse accuracy of the pulse.

[0232] Step S203: Calculate the die-cutting waiting pulse number according to the pulse accuracy and the first distance.

[0233] Correspondingly, the step S30 includes:

[0234] Step S30': After the die-cutting waiting pulse number, perform die-cutting on the pole piece at the die-cutting position of the pole piece to obtain the first pole ear.

[0235] Considering that in some cases, the pole piece tape running is not uniform. At this time, if the laser is still controlled to die-cut the first pole ear according to the die-cutting waiting time, it may cause the position of the first pole ear to be inaccurate. Therefore, in this embodiment, the die-cutting waiting pulse number is calculated according to the encoder accuracy. After the die-cutting waiting pulse number, the laser is controlled to perform die-cutting on the pole piece to obtain the first pole ear.

[0236] For the convenience of understanding, the following is an example, but it does not limit the present application. As an example, assume that the designed distance between the starting point of the thickness thinning area and the midpoint of the first pole ear is L. The main working steps of the gap die-cutting detection system include:

[0237] 1. Collect the pole piece thickness data of the pole piece.

[0238] 2. Determine the starting point of the thickness thinning area according to the change of the pole piece thickness data.

[0239] 3. Calculate the first distance L1 from the starting point of the thickness thinning area to the laser.

[0240] 4. Calculate the die-cutting waiting pulse number X = (L1 - L) / P according to the first distance L1 from the starting point of the thickness thinning area to the laser, the designed distance L between the starting point of the thickness thinning area and the midpoint of the first pole ear, and the encoder accuracy P. The laser starts to cut the first pole ear after waiting for X pulses. Here, the encoder accuracy P represents the number of pulses generated by the encoder per revolution.

[0241] 5. The camera takes a picture of the pole piece after laser die-cutting. In addition to calculating the conventional pole piece defects and dimensions, it can also detect whether the actual distance between the starting point of the thickness thinning area and the midpoint of the first pole ear is equal to the designed distance between the starting point of the thickness thinning area and the midpoint of the first pole ear.

[0242] In this embodiment, the number of die-cutting waiting pulses is calculated according to the pulse accuracy. After an interval of the die-cutting waiting pulses, the pole piece is die-cut to obtain the first tab, so that the influence of the pole piece running speed on the die-cutting of the first tab can be reduced, and the accuracy of die-cutting the first tab can be improved accordingly.

[0243] In some embodiments, after the die-cutting waiting time interval, when die-cutting the pole piece at the die-cutting position of the pole piece to obtain the first tab, the following steps are further included: obtaining the die-cutting error of the first tab according to the image of the pole piece after die-cutting; if the die-cutting error is not within the preset error range, generating an error correction instruction according to the die-cutting error; after an interval of the die-cutting waiting time, die-cutting the pole piece at the die-cutting position of the pole piece according to the error correction instruction to obtain the next first tab.

[0244] In order to correct the process of laser die-cutting the first tab in a timely manner, in this embodiment, the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is obtained through the image of the pole piece after die-cutting, and the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab is obtained. The laser is controlled according to whether the die-cutting error between the actual distance and the designed distance is within the preset error range, so as to form a complete closed-loop detection system.

[0245] For the sake of easy understanding, the following is an example, but it does not limit the present application. As an example, assuming that the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab is L, the main working steps of the gap die-cutting detection system include:

[0246] 1. Collect the pole piece thickness data of the pole piece.

[0247] 2. Determine the starting point of the thickness thinning area according to the change of the pole piece thickness data.

[0248] 3. Calculate the first distance L1 from the starting point of the thickness thinning area to the laser.

[0249] 4. Calculate the number of die-cutting waiting pulses X = (L1 - L) / P according to the first distance L1 from the starting point of the thickness thinning area to the laser, the designed distance L between the starting point of the thickness thinning area and the midpoint of the first tab, and the encoder accuracy P. The laser waits for X pulses and then starts to cut the first tab, where the encoder accuracy P represents the number of pulses generated by the encoder per revolution.

[0250] 5. The camera takes a picture of the pole piece after laser die-cutting. In addition to calculating the conventional pole piece defects and dimensions, it can also detect whether the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab is equal to the designed distance between the starting point of the thickness thinning area and the midpoint of the first tab.

[0251] 6. Obtain the designed spacing between the starting point of the thickness thinning area and the midpoint of the first tab, and calculate the spacing error between the actual spacing and the designed spacing; if the spacing error is within the preset error range, return to step 1 and continue die-cutting the next first tab, where the preset error range can be an error range preset according to the specification requirements, and this embodiment does not limit this.

[0252] 7. If the spacing error is not within the preset error range, perform closed-loop control with the laser. Specifically, it can be: the controller generates an error correction instruction according to the spacing error and sends the error correction instruction to the laser; after the laser waits for X pulses, it die-cuts the pole piece according to the error correction instruction to obtain the next first tab.

[0253] In this embodiment, the die-cutting error of the first tab is obtained through the image of the pole piece after die-cutting. If the die-cutting error is not within the preset error range, an error correction instruction is generated according to the die-cutting error to control the laser, thereby forming a complete closed-loop detection system, and then being able to correct errors in the process of the laser die-cutting the first tab in a timely manner, improving the reliability of the die-cutting system.

[0254] In some embodiments, the calculating the first distance from the starting point of the thickness thinning area to the die-cutting position of the pole piece includes: obtaining the second distance between the acquisition position of the pole piece thickness data and the die-cutting position of the pole piece; obtaining the running distance of the pole piece when collecting the pole piece thickness data; calculating the first distance from the starting point of the thickness thinning area to the die-cutting position of the pole piece according to the second distance and the running distance.

[0255] To improve the accuracy of the first distance, in this embodiment, when calculating the first distance, the second distance from the sensor to the laser and the running distance of the pole piece when the sensor collects the pole piece thickness data are also considered.

[0256] For ease of understanding, reference is made to Figure 6 and Figure 7 for illustration, but this does not limit the present application. As an example, assume that the designed spacing between the starting point of the thickness thinning area and the midpoint of the first tab is L, and the running direction of the pole piece is as shown by the arrow in the figure. The die-cutting system includes a guide roller 60, a sensor 50, a controller, a laser 51, an encoder 61, an image collector 63, and a coding roller 62 corresponding to the encoder 61. The main working steps of the gap die-cutting detection system include:

[0257] 1. The guide roller 60 drives the pole piece to run, the running of the pole piece drives the coding roller 62 to rotate, the rotation of the coding roller 62 drives the encoder 61 to trigger a pulse, and after the sensor 50 receives the pulse trigger, it collects the pole piece thickness data at this time, with 5000 data as a group (which can be preset in advance).

[0258] 2. For the collected data, first preliminarily determine whether the data is an inflection point. The judgment logic is to compare the collected data with the preset data. The preset data is the value obtained by adding the thickness of the electrode in the thickness thinning area and the thickness of the electrode in the non-thickness thinning area and then dividing by 2. If the collected data is less than the preset value and the subsequent 500 points (can be set) are continuously less than this value, then this point is a descending mutation point; similarly, if the collected data is greater than the preset value and the subsequent 500 points (can be set) are continuously greater than this value, then this point is an ascending mutation point.

[0259] 3. According to the positions of the found mutation points, smooth the 500 data before and after the mutation points, and then calculate the derivative to find the inflection points of the thickness thinning area.

[0260] 4. Assume that the first inflection point (i.e., the starting point of the thickness thinning area) of the thickness thinning area is the Mth point in the Nth group of arrays. After the N + 1th group of data is collected, calculate the first distance L1 from the starting point of the thickness thinning area to the laser 51 through the following formula:

[0261] L1 = L2 - (2 * 5000 - M) * P * m / d

[0262] In the formula, L1 represents the distance from the starting point of the thickness thinning area to the laser 51, L2 represents the distance between the sensor 50 and the laser 51, (2 * 5000 - M) * P * m / d represents the running distance of the electrode when the sensor collects the electrode thickness data, (2 * 5000 - M) represents the number of interval data points between the starting point of the thickness thinning area and the end point of this data collection, P represents the encoder 61 accuracy, m represents the frequency division of the sensor 50, and d represents the frequency division of the sensor 50.

[0263] 5. According to the first distance L1 from the starting point of the thickness thinning area to the laser 51, the designed distance L between the starting point of the thickness thinning area and the midpoint of the first tab, and the encoder 61 accuracy P, calculate the die-cutting waiting pulse number X = (L1 - L) / P. The laser 51 waits for X pulses and then starts to cut the first tab.

[0264] 6. The image collector 63 collects pictures of the gap electrode and the tab, calculates the position from the first inflection point of the thickness thinning area to the tab according to the pictures, finds the tab contour according to the threshold, and then calculates the center position of the tab. According to the pictures, find the position of the edge of the thickness thinning area, and then calculate the actual distance between the starting point of the thickness thinning area and the midpoint of the first tab.

[0265] 7. Obtain the designed spacing between the starting point of the thickness-thinned area and the midpoint of the first tab, calculate the spacing error between the actual spacing and the designed spacing. If the spacing error is not within the preset error range, generate an error correction instruction according to the spacing error and the requirements of the actual process, and send the error correction instruction to the laser 51. The laser 51 then die-cuts the next first tab, and compensates the distance at which the laser 51 cuts the tab according to the error correction instruction.

[0266] In this embodiment, when calculating the first distance, the second distance from the sensor to the laser and the running distance of the tab when the sensor collects the tab thickness data are also considered, so as to improve the accuracy of the first distance calculation, and further improve the accuracy of the first tab die-cutting.

[0267] In some embodiments, the defect detection of the die-cut tab according to the image of the die-cut tab includes: obtaining the frequency characteristics of the image of the die-cut tab, removing noise from the image of the die-cut tab according to the frequency characteristics to obtain a processed image; obtaining the edge texture image of the die-cut tab according to the image of the die-cut tab and the processed image; and performing defect detection on the die-cut tab according to the edge texture image.

[0268] In this embodiment, the appearance of the gap tab is also detected. Since the traditional lighting scheme cannot effectively identify the trailing defect of the gap coating, in this embodiment, a lighting scheme for the gap trailing defect is designed, specifically as Figure 17 shown Figure 17 is the three-view drawing of the image collector of some embodiments of the present invention. The image collector may include a camera 160 and a lighting device 161. The camera 160 is arranged on one side of the tab, and the lighting device 161 is arranged on the other side of the tab. The position of the camera 160 corresponds to the position of the lighting device 161. Among them, the setting method of the camera 160 is: 1. Stand facing the incoming material direction; 2. The camera field of view is 300 mm; 3. The working distance is 245 mm. The setting method of the lighting device 161 is: the working distance is 40 mm.

[0269] Considering that the trailing is close to the background gray value and there is no effective method for detection in the spatial domain (gray value). Therefore, in this embodiment, first obtain the frequency characteristics of the image of the die-cut tab, then remove noise from the image of the die-cut tab according to the frequency characteristics to obtain a processed image, then obtain the edge texture image of the die-cut tab according to the image of the die-cut tab and the processed image, and perform defect detection on the die-cut tab according to the edge texture image.

[0270] For ease of understanding, the following is an example, but it does not limit the present application. As an example, the gap coating trailing detection includes:

[0271] 1. Image acquisition: Acquire the image of the die-cut pole piece.

[0272] 2. Transfer the image from the spatial domain to the frequency domain:

[0273] The spatial domain is the representation of an image on a two-dimensional plane, while the frequency domain is the representation of an image in terms of frequency. Transferring an image from the spatial domain to the frequency domain means converting the pixel representation of the image in space to a spectral representation in frequency through Fourier transform. In specific implementation, a two-dimensional discrete Fourier transform (DFT) or a fast Fourier transform (FFT) can be used to achieve this conversion. The frequency domain representation helps analyze the frequency characteristics of the image, such as high-frequency noise and low-frequency texture. For example, in image processing software, an FFT algorithm can be used to convert a grayscale image from the spatial domain to the frequency domain to obtain its spectrogram.

[0274] 3. Create a low-pass (such as Gaussian) filter:

[0275] The trailing to be detected appears as texture and contour in the spatial domain, and it is a low-frequency feature in the frequency domain. Therefore, low-pass filtering is required. A low-pass filter is a filter that allows low-frequency signals to pass through while attenuating high-frequency signals. A Gaussian filter is a filter with the shape of a Gaussian function, whose frequency response is highest at the center frequency and gradually decreases as the frequency increases. In specific implementation, when creating a Gaussian filter, parameters of the filter such as the cut-off frequency and standard deviation need to be set, and then a filter function with a Gaussian shape is generated. The Gaussian filter can effectively smooth the image and remove high-frequency noise. For example, in image processing software, a Gaussian filter with a standard deviation of σ can be set and then applied to the image to smooth the noise.

[0276] 4. Multiply the frequency-domain image by the filter:

[0277] This step is to multiply the image in the frequency domain by the filter function point by point to change the frequency characteristics of the image. In the frequency domain, both the image and the filter are two-dimensional matrices, and point-by-point multiplication means multiplying the corresponding elements. Through the multiplication operation, certain frequency components in the image can be suppressed or enhanced. For example, multiplying the Gaussian filter by the frequency-domain image can suppress high-frequency noise and retain low-frequency texture.

[0278] 5. Convert the frequency-domain image back to the spatial domain:

[0279] This step is to convert the filtered frequency-domain image back to the spatial domain to obtain the processed image. In specific implementation, a two-dimensional inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT) can be used to achieve this conversion. After converting back to the spatial domain, a smoothed image can be obtained. For example, in image processing software, an IFFT algorithm can be used to convert the frequency-domain image back to the spatial domain to obtain the processed image.

[0280] 6. Perform a difference operation between the transformed image and the original image:

[0281] The difference operation refers to calculating the pixel differences between two images. Subtract the original image from the transformed image point by point to obtain a difference image. The difference image can highlight the changing parts in the image, such as edges and textures. For example, performing a difference operation between the smoothed image and the original image can obtain a difference image that highlights the edges and textures.

[0282] 7. Use the blob algorithm to filter out trailing tails based on length, width, area size, and aspect ratio

[0283] The Blob (Binary Large OBject) algorithm is an algorithm used in image processing and computer vision for detecting and analyzing connected regions in an image. Trailing tails usually refer to the long, strip-shaped parts in an image with obvious differences in brightness or color from the surrounding area. Using the Blob algorithm to detect the connected regions in the image and filtering based on features such as its length, width, area size, and aspect ratio can accurately detect the trailing tails in the image. For example, in machine vision applications, the Blob algorithm can be used to detect scratches or linear defects in an image and filter and classify them based on their length, width, etc.

[0284] 8. Use the minimum bounding rectangle fitting to output the length and width of the trailing tail:

[0285] The minimum bounding rectangle fitting means finding a smallest rectangular area that can completely enclose a certain connected region (such as a trailing tail) in the image. By calculating the bounding rectangle of the connected region and finding its minimum size, the minimum bounding rectangle can be obtained, and then the length and width of this rectangle are output as the size of the trailing tail, so that the length and width of the trailing tail can be accurately measured. For example, in image processing software, the minimum bounding rectangle fitting algorithm can be used to measure the length and width of scratches or linear defects in an image.

[0286] In this embodiment, first, the frequency characteristics of the image of the die-cut pole piece are obtained, then the noise of the image of the die-cut pole piece is removed according to the frequency characteristics to obtain a processed image, and then the edge texture image of the die-cut pole piece is obtained based on the image of the die-cut pole piece and the processed image, and the die-cut pole piece is defect-detected according to the edge texture image, so as to improve the accuracy of the trailing tail detection of the gap coating.

[0287] In some embodiments, determining the starting point of the thickness thinning region according to the change of the pole piece thickness data includes: constructing an objective function according to the pole piece thickness data, where the objective function is used to represent the thickness change of the pole piece; determining the inflection point of the thickness thinning region according to the objective function; and determining the starting point of the thickness thinning region according to the inflection point of the thickness thinning region and the running direction of the pole piece.

[0288] To improve the accuracy of the starting point of the thickness thinning region, in this embodiment, the pole piece thickness data is first subjected to filtering and smoothing processing, and then the smoothed data is fitted with a logistic function to obtain the fitted logistic function (i.e., the objective function). Then, the derivative of the fitted logistic function is calculated, and the inflection point of the thickness thinning region is determined according to the derivative of the logistic function. Finally, the starting point of the thickness thinning region is determined according to the inflection point of the thickness thinning region and the running direction of the pole piece.

[0289] In this embodiment, an objective function is first constructed according to the pole piece thickness data, then the inflection point of the thickness thinning region is determined according to the objective function, and the starting point of the thickness thinning region is determined according to the inflection point of the thickness thinning region and the running direction of the pole piece, thereby improving the accuracy of the starting point of the thickness thinning region.

[0290] In some embodiments, determining the inflection point of the thickness thinning region according to the objective function includes: calculating the intersection point between a preset threshold and the objective function; and determining the inflection point of the thickness thinning region according to the intersection point.

[0291] To accurately calculate the inflection point of the thickness thinning region, in this embodiment, the intersection point between a preset threshold and the derivative of the logistic function can be calculated, and the inflection point of the thickness thinning region is determined according to the intersection point. For ease of understanding, reference is made to Figure 10 and Figure 18 for illustration, but it does not limit the present application. Figure 10 FIG. is a schematic diagram of the thickness of the thickness thinning region in some embodiments of the present invention. Figure 10 The thickness thinning region in FIG. includes four inflection points A, B, C, and D. Figure 18 FIG. is a schematic diagram of finding the inflection point of the thickness thinning region in some embodiments of the present invention. Figure 18 In FIG., the steps of finding the inflection point of the thickness thinning region include:

[0292] 1. After processing the data measured by the sensor, the pole piece thickness data can be obtained.

[0293] 2. First, perform filtering and smoothing processing on the pole piece thickness data.

[0294] 3. Then, perform logistic function fitting on the smoothed pole piece thickness data.

[0295] 4. Take the derivative of the fitted logistic function.

[0296] 5. Find the intersection point of the threshold line and the derivative of the logistic function, as shown in Figure 18 as follows.

[0297] 6. The abscissa of the intersection point is the abscissa of the inflection point, and thus the two inflection points C and D of the falling edge can be found. Similarly, the two inflection points A and B of the rising edge can be obtained.

[0298] Assume that the running direction of the pole piece is as shown in Figure 10 as follows. Then, in the running direction, the inflection point D is in front of the inflection point A, and the inflection point D is taken as the starting point of the thickness thinning area. In specific implementation, the coordinates of point A can also be used as a reference. Take N points to the left of point A and calculate the average, which can be used as the coating area thickness of the pole piece; take the midpoint of points B and C as a reference, and the average value of N / 2 points on both the left and right sides of the midpoint is the thickness of the thickness thinning area of the pole piece.

[0299] In this embodiment, by calculating the intersection point between the preset threshold and the derivative of the logical function, the inflection points of the thickness thinning area are determined according to the intersection point, so that the inflection points of the thickness thinning area can be calculated.

[0300] In some embodiments, determining the inflection points of the thickness thinning area according to the objective function includes: calculating the maximum or minimum value of the objective function; determining the inflection points of the thickness thinning area according to the maximum or minimum value.

[0301] In the actual working environment, due to mechanical jitter, the measured thickness fluctuates, which affects the search for the inflection points of the gap coating. Therefore, in order to improve the accuracy of the coating gap inflection points, in this embodiment, based on the measurement scheme of the steepest descent / steepest ascent points, the inflection points can also be stably found in a jitter environment.

[0302] For ease of understanding, reference is made to Figure 10 and Figure 19 for illustration, but the present application is not limited thereto. Figure 10 is a schematic diagram of the thickness of the thickness thinning area in some embodiments of the present invention. Figure 10 The thickness thinning area in it includes four inflection points A, B, C, and D. Figure 19 is a schematic diagram of finding the inflection points of the thickness thinning area in some embodiments of the present invention. Figure 19 In it, the steps of finding the inflection points of the thickness thinning area include:

[0303] 1. After processing the data measured by the sensor, the pole piece thickness data can be obtained.

[0304] 2. First, perform filtering and smoothing processing on the pole piece thickness data.

[0305] 3. Then, perform logistic function fitting on the smoothed pole piece thickness data.

[0306] 4. Take the derivative of the fitted logistic function.

[0307] 5. Find the value where the derivative of the logistic function is maximum, as Figure 19 shown.

[0308] 6. The abscissa of the maximum value of the derivative is the abscissa of the center point of the inflection point. As Figure 19 shown, the abscissa of the maximum value of the derivative is essentially the center point of inflection points C and D. Based on this center point, the abscissas of inflection points C and D can be obtained. Similarly, the abscissas of the two inflection points A and B can be obtained.

[0309] Assume the running direction of the electrode sheet is as Figure 10 shown. Then, in the running direction, inflection point D is in front of inflection point A. Take inflection point D as the starting point of the thickness thinning area.

[0310] This embodiment determines the inflection points of the thickness thinning area based on the measurement scheme of the steepest descent / steepest ascent points, so as to improve the accuracy of the inflection points of the coating gap, and further improve the calculation accuracy of the length of the thickness thinning area and the length of each electrode sheet strip.

[0311] In some embodiments, after determining the inflection points of the thickness thinning area according to the objective function, it further includes: obtaining the inflection point coordinates of the thickness thinning area and the starting point coordinates of each electrode sheet strip, where the electrode sheet strip is the strip corresponding to the electrode of one cell length; calculating the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area, and calculating the length of each electrode sheet strip according to the starting point coordinates of each electrode sheet strip.

[0312] In order to accurately calculate the length of the thickness thinning area and the length of each electrode sheet strip, in this embodiment, the length of the thickness thinning area is calculated according to the inflection point coordinates of the thickness thinning area, and the length of each electrode sheet strip is calculated according to the starting point coordinates of each electrode sheet strip.

[0313] For the sake of easy understanding, reference is made to Figure 10 for illustration, but it does not limit this application. Figure 10 This is the thickness schematic diagram of the thickness thinning area in some embodiments of the present invention. As an example, after obtaining the abscissas of the four points A, B, C, and D, the lengths of the three regions AB, BC, and CD can be directly calculated according to the abscissas of the four points A, B, C, and D. Then, the length of the thickness thinning area can be calculated based on the lengths of the three regions AB, BC, and CD. Similarly, the length of each electrode sheet strip can be calculated according to the starting point coordinates of each electrode sheet strip.

[0314] In this embodiment, the length of the thickness thinning area is calculated based on the inflection point coordinates of the thickness thinning area, and the length of each pole piece strip is calculated based on the starting point coordinates of each pole piece strip, so that the length of the thickness thinning area and the length of each pole piece strip can be accurately calculated.

[0315] In some embodiments, before calculating the length of the thickness thinning area according to the inflection point coordinates of the thickness thinning area and calculating the length of each pole piece strip according to the starting point coordinates of each pole piece strip, it further includes: collecting a calibration image of a calibration ruler and obtaining calibration ruler parameters of the calibration ruler; calculating a calibration accuracy according to the calibration image and the calibration ruler parameters, where the calibration accuracy is used to represent the mapping relationship between the pixel distance and the actual distance; correspondingly, calculating the length of the thickness thinning area according to the calibration accuracy and the inflection point coordinates of the thickness thinning area, and calculating the length of each pole piece strip according to the calibration accuracy and the starting point coordinates of each pole piece strip.

[0316] In order to further improve the accuracy of the length of the thickness thinning area and the length of each pole piece strip, in this embodiment, the target calibration accuracy can be determined first, and then the length of the coating gap area is calculated according to the target calibration accuracy and the inflection point coordinates of the coating gap area, and the length of each pole piece strip is calculated according to the target calibration accuracy and the starting point coordinates of each pole piece strip.

[0317] In a specific implementation, the sensor can be indirectly calibrated by calibrating an image collector. For ease of understanding, reference is made to Figure 11 and Figure 12 for illustration, but it does not limit the present application. Figure 11 is a schematic diagram of a calibration ruler according to some embodiments of the present invention, Figure 12 is a schematic diagram of a calibration image according to some embodiments of the present invention. The calibration method of this embodiment requires the use of Figure 11 the shown film ruler. This film ruler is made of white non-transparent soft film material, and the pattern consists of 15mm black and white rectangular shapes. This calibration method uses an encoder to trigger an image collector (such as a camera) to collect a picture of the film ruler. According to the collected picture, as shown in Figure 11 , the longitudinal resolution of the picture is calculated, and then the pulse accuracy of the encoder is obtained. Then, the target calibration accuracy of the sensor (such as a spectral confocal displacement sensor) in the tape running direction is calculated. The specific steps are as follows:

[0318] 1. Stick the calibration ruler with black and white intervals on the roller, and the encoder triggers image acquisition.

[0319] 2. The camera captures S complete black and white grids, and the algorithm measures the number of rows K occupied by the S black and white grids.

[0320] 3. The first calibration accuracy P1 of the camera in the tape running direction is P1 = S * 15 / K.

[0321] 4. The second calibration accuracy P2 of the encoder in the tape running direction is P2 = P / the camera multiplication factor.

[0322] 5. The target calibration accuracy P3 of the spectral confocal position in the tape running direction is P3 = P2 * the point spectral multiplication factor.

[0323] In this embodiment, by calibrating the image collector and indirectly calibrating the sensor, the target calibration accuracy can be determined, and the accuracy of calculating the length of the thickness thinning area and the length of each pole piece tape can be improved in the subsequent process.

[0324] In some embodiments, collecting the pole piece thickness data of the pole piece includes: emitting detection light of different wavelengths to the pole piece. When the detection light of different wavelengths irradiates the pole piece, the light of the unfocused wavelength in the returned light of the pole piece is blocked; receiving the returned light of the pole piece, obtaining the light wavelength of the returned light, and looking up the pole piece thickness data corresponding to the light wavelength in a preset wavelength relationship table, where the preset wavelength relationship table includes the corresponding relationship between the light wavelength and the pole piece thickness data.

[0325] For ease of understanding, the following is an example, but it does not limit the present application. As an example, assume that the instrument for thickness measurement is a spectral confocal displacement sensor, and its measurement principle is: the white point light source forms a conical dispersion light source after passing through the dispersion confocal probe. The dispersion angles of light of different wavelengths are different, and the light of different wavelengths is confocal at different positions. When the light source irradiates an object at different heights, the light spot on the object returns through the coaxial optical path and passes through the small aperture diaphragm and is connected to the spectrometer. The light of the unfocused wavelength is blocked and attenuated by the diaphragm (i.e., the spectral splitting component) after returning, and the wavelength of the light received by the spectrometer (i.e., the detector) can reflect the height information of the object. When the distance from the target changes, the wavelength of the focused light also changes, resulting in different spectral distributions in the spectrometer. Compared with the point laser thickness measurement, the spectral confocal displacement sensor has a small volume, a small measurement blind area, and strong anti-interference ability.

[0326] For ease of understanding, reference is made to Figure 13 for illustration, but it does not limit the present application. Figure 13 FIG. is a schematic diagram of thickness measurement by the spectral confocal displacement sensor in some embodiments of the present invention. Figure 13 In it, the measurement steps are as follows:

[0327] 1. Adjust the first spectral confocal displacement sensor 101 and the second spectral confocal displacement sensor 102 to be confocal.

[0328] 2. Calibration is performed using a calibration sheet 100 with a thickness of 0.5 mm, and the purpose is to obtain the distance H between the first spectral confocal displacement sensor 101 and the second spectral confocal displacement sensor 102.

[0329] 3. Calculate the thickness of the object to be measured according to the following formula:

[0330] h = H - A - B

[0331] In the formula, H represents the distance between the first spectral confocal displacement sensor 101 and the second spectral confocal displacement sensor 102, A represents the distance from the upper sensor to the object to be measured, B represents the distance from the lower sensor to the object to be measured, and h represents the thickness of the object to be measured.

[0332] In this embodiment, the thickness data of the pole piece is collected by the light wavelength of the return light of the pole piece, so that the volume of the sensor can be reduced, the measurement blind area can be reduced, and the anti-interference ability can be improved.

[0333] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A die-cutting system, characterized in that: The die-cutting system includes: a sensor, a controller and a laser; The sensor is used to collect the pole piece thickness data of the pole piece and send the pole piece thickness data to the controller; The controller is used to determine the starting point of the thickness thinning zone according to the change of the pole piece thickness data, calculate the first distance from the starting point of the thickness thinning zone to the laser, calculate the die-cutting waiting time according to the first distance, and send the die-cutting waiting time to the laser; The laser is used to die-cut the pole piece after the die-cutting waiting time to obtain the first pole ear; The step of calculating the die-cutting waiting time according to the first distance includes: The die-cutting waiting time is calculated according to the difference between the first distance and the designed spacing, wherein the designed spacing is the distance between the starting point of the thickness reduction area and the midpoint of the first pole ear.

2. The die-cutting system according to claim 1, characterized in that: The die-cutting system further includes: an encoder, an image collector, and an encoding roller corresponding to the encoder; the encoding roller is driven to rotate when the pole piece is conveyed, and the rotation of the encoding roller drives the encoder to trigger a pulse; The sensor is used to collect the pole piece thickness data of the pole piece in response to the pulse, and send the pole piece thickness data to the controller; The image collector is used to collect the image of the pole piece after die cutting in response to the pulse, and send the image of the pole piece after die cutting to the controller; The controller is used to perform defect detection on the die-cut pole piece according to the image of the die-cut pole piece.

3. The die-cutting system according to claim 2, characterized in that: The die-cutting waiting time is the number of die-cutting waiting pulses; The controller is further used to obtain the encoder accuracy of the encoder, and calculate the die-cutting waiting pulse number according to the encoder accuracy and the first distance; and send the die-cutting waiting pulse number to the laser; The laser is also used to die-cut the pole piece after the die-cutting waiting pulse number is spaced to obtain the first pole ear.

4. The die-cutting system according to claim 2, characterized in that: The controller is further configured to obtain a die-cutting error of the first pole tab according to the image of the pole piece after die-cutting; if the die-cutting error is not within a preset error range, generate an error correction instruction according to the die-cutting error; The laser is also used to die-cut the pole piece according to the error correction instruction after the die-cutting waiting time to obtain the next first pole ear.

5. The die-cutting system according to claim 2, characterized in that: The controller is also used to obtain a second distance from the sensor to the laser, and to obtain a running distance of the pole piece when the sensor collects the pole piece thickness data; and to calculate a first distance from the starting point of the thickness thinning zone to the laser based on the second distance and the running distance.

6. The die-cutting system according to claim 2, characterized in that: The sensor, the laser, the encoding roller and the image collector are arranged in sequence in the tape running direction of the pole piece, the data acquisition direction of the sensor is perpendicular to the tape running direction of the pole piece, the light outlet of the laser is perpendicular to the tape running direction of the pole piece, and the image acquisition direction of the image collector is perpendicular to the tape running direction of the pole piece.

7. The die-cutting system according to claim 6, characterized in that: The sensor comprises a first sensor and a second sensor, wherein the first sensor and the second sensor are arranged on both sides of the pole piece in a facing manner, and data acquisition directions of the first sensor and the second sensor are perpendicular to the pole piece.

8. The die-cutting system according to claim 6, characterized in that: The image collector includes a first image collector, a second image collector, a third image collector and a fourth image collector; The first image collector is used to detect the front defects of the electrode sheet after die-cutting; The second image collector is used to detect backlight defects of the die-cutting electrode sheet; The third image collector and the fourth image collector are used to detect the back surface defects of the electrode sheet after die-cutting.

9. The die-cutting system according to claim 8, characterized in that: The first image collector includes a first camera and a first light source, and the first camera and the first light source are arranged on the same side of the pole piece; the second image collector includes a second camera and a second light source, and the second camera and the second light source are respectively arranged on both sides of the pole piece; the third image collector includes a third camera and a third light source, and the third camera and the third light source are arranged on the same side of the pole piece; the fourth image collector includes a fourth camera and a fourth light source, and the fourth camera and the fourth light source are arranged on the same side of the pole piece.

10. The die-cutting system according to any one of claims 2 to 9, characterized in that: The controller is also used to obtain the inflection point coordinates of the thickness thinning zone and the starting point coordinates of each pole piece strip, wherein the pole piece strip is a strip corresponding to a pole piece with a length of a battery cell; the length of the thickness thinning zone is calculated according to the inflection point coordinates of the thickness thinning zone, and the length of each pole piece strip is calculated according to the starting point coordinates of each pole piece strip.

11. The die-cutting system according to claim 10, characterized in that: The die-cutting system further comprises: a calibration ruler, which is arranged on the encoding roller; the calibration ruler is driven to rotate by the rotation of the encoding roller, and the rotation of the encoding roller drives the encoder to trigger the calibration pulse; The image collector is further used to collect a calibration image of the calibration ruler in response to the calibration pulse, and send the calibration image to the controller; The controller is further used to obtain calibration scale parameters of the calibration scale, calculate the calibration accuracy according to the calibration image and the calibration scale parameters, wherein the calibration accuracy is used to represent the mapping relationship between pixel distance and actual distance; calculate the length of the thickness thinning area according to the calibration accuracy and the inflection point coordinates of the thickness thinning area, and calculate the length of each pole piece strip according to the calibration accuracy and the starting point coordinates of each pole piece strip.

12. The die-cutting system according to any one of claims 1 to 9, characterized in that: The sensor is a spectral confocal displacement sensor, which includes: a point light source, a dispersive confocal probe, a spectroscopic component and a detector; The point light source is used to emit detection light to the pole piece, and the detection light forms detection light of different wavelengths after passing through the dispersive confocal probe, wherein when the detection light of different wavelengths is irradiated onto the pole piece, the return light of the pole piece is connected to the detector through the light splitting component, and the light splitting component is used to shield the light of unfocused wavelength in the return light; The detector is used to obtain the wavelength of the returning light, and search for the pole piece thickness data corresponding to the wavelength of the light in a preset wavelength relationship table, wherein the preset wavelength relationship table includes the correspondence between the wavelength of the light and the pole piece thickness data; and send the pole piece thickness data to the controller.

13. A die cutting method, characterized in that: include: Collecting the pole piece thickness data of the pole piece; Determine the starting point of the thickness thinning zone according to the change of the electrode thickness data, calculate the first distance from the starting point of the thickness thinning zone to the electrode die-cutting position, and calculate the die-cutting waiting time according to the first distance; After the die-cutting waiting time, die-cutting the pole piece at the pole piece die-cutting position to obtain a first pole ear; The step of calculating the die-cutting waiting time according to the first distance includes: The die-cutting waiting time is calculated according to the difference between the first distance and the designed spacing, wherein the designed spacing is the distance between the starting point of the thickness reduction area and the midpoint of the first pole ear.

14. The die-cutting method according to claim 13, characterized in that: Before collecting the pole piece thickness data of the pole piece, the method further includes: When the pole piece is running, the pulse is triggered; The collecting of the pole piece thickness data of the pole piece comprises: In response to the pulse, collecting pole piece thickness data of the pole piece; After the die-cutting waiting time, the electrode piece is die-cut at the electrode piece die-cutting position to obtain the first electrode ear, and the method further includes: In response to the pulse, an image of the die-cut pole piece is collected, and defect detection is performed on the die-cut pole piece based on the image of the die-cut pole piece.

15. The die-cutting method according to claim 14, characterized in that: The die-cutting waiting time is the number of die-cutting waiting pulses; and the die-cutting waiting time is calculated according to the first distance, including: Obtaining the accuracy of the encoder that triggers the pulse; Calculate the number of die-cutting waiting pulses according to the encoder accuracy and the first distance; Correspondingly, after the die-cutting waiting time, die-cutting the pole piece at the pole piece die-cutting position to obtain the first pole ear includes: After the die-cutting waiting pulse number is exceeded, the pole piece is die-cut at the pole piece die-cutting position to obtain a first pole ear.

16. The die-cutting method according to claim 14, characterized in that: After the die-cutting waiting time, the electrode piece is die-cut at the electrode piece die-cutting position to obtain the first electrode ear, and the method further includes: Acquire a die-cutting error of the first pole tab according to the image of the pole piece after die-cutting; If the die-cutting error is not within the preset error range, generating an error correction instruction according to the die-cutting error; After the die-cutting waiting time, the pole piece is die-cut at the pole piece die-cutting position according to the error correction instruction to obtain the next first pole lug.

17. The die-cutting method according to claim 14, characterized in that: The calculation of the first distance from the starting point of the thickness thinning area to the pole piece die cutting position includes: Acquire a second distance between a collection position of the pole piece thickness data and a pole piece die-cutting position; Acquiring the walking distance of the pole piece when collecting the pole piece thickness data; The first distance from the starting point of the thickness thinning zone to the pole piece die-cutting position is calculated according to the second distance and the tape running distance.

18. The die-cutting method according to claim 14, characterized in that: The defect detection of the die-cutting electrode sheet according to the image of the die-cutting electrode sheet comprises: Acquiring frequency characteristics of the image of the electrode sheet after die-cutting, and removing noise from the image of the electrode sheet after die-cutting according to the frequency characteristics to obtain a processed image; Acquire an edge texture image of the electrode sheet after die-cutting according to the image of the electrode sheet after die-cutting and the processed image; Defect detection is performed on the die-cutting rear electrode according to the edge texture image.

19. The die cutting method according to any one of claims 13 to 18, characterized in that: Determining the starting point of the thickness thinning area according to the change of the pole piece thickness data includes: Constructing an objective function according to the pole piece thickness data, wherein the objective function is used to represent the thickness change of the pole piece; Determining the inflection point of the thickness thinning zone according to the objective function; The starting point of the thickness thinning zone is determined according to the inflection point of the thickness thinning zone and the tape running direction of the pole piece.

20. The die-cutting method according to claim 19, characterized in that: Determining the inflection point of the thickness thinning zone according to the objective function includes: Calculating the intersection point between a preset threshold and the objective function; The inflection point of the thickness reduction zone is determined according to the intersection point.

21. The die cutting method according to claim 19, characterized in that: Determining the inflection point of the thickness thinning zone according to the objective function includes: Calculating the maximum or minimum value of the objective function; The inflection point of the thickness reduction zone is determined according to the maximum value or the minimum value.

22. The die cutting method according to claim 19, characterized in that: After determining the inflection point of the thickness thinning area according to the objective function, the method further includes: Obtaining the inflection point coordinates of the thickness thinning area and the starting point coordinates of each pole piece strip, wherein the pole piece strip is a strip corresponding to a pole piece of a battery cell length; The length of the thickness thinning zone is calculated according to the coordinates of the inflection point of the thickness thinning zone, and the length of each pole piece strip is calculated according to the coordinates of the starting point of each pole piece strip.

23. The die cutting method according to claim 22, characterized in that: Before calculating the length of the thickness thinning zone according to the inflection point coordinates of the thickness thinning zone and calculating the length of each pole piece strip according to the starting point coordinates of each pole piece strip, the method further includes: Acquiring a calibration image of the calibration ruler and obtaining calibration ruler parameters of the calibration ruler; Calculating a calibration accuracy according to the calibration image and the calibration ruler parameters, wherein the calibration accuracy is used to represent a mapping relationship between a pixel distance and an actual distance; Accordingly, the calculating of the length of the thickness thinning zone according to the inflection point coordinates of the thickness thinning zone, and the calculating of the length of each pole piece strip according to the starting point coordinates of each pole piece strip, comprises: The length of the thickness thinning zone is calculated according to the calibration accuracy and the coordinates of the inflection point of the thickness thinning zone, and the length of each pole piece strip is calculated according to the calibration accuracy and the coordinates of the starting point of each pole piece strip.

24. The die cutting method according to any one of claims 13 to 18, characterized in that: The collecting of the pole piece thickness data of the pole piece comprises: emitting detection light of different wavelengths to the pole piece, wherein when the detection light of different wavelengths is irradiated onto the pole piece, the light of unfocused wavelength in the return light of the pole piece is blocked; Receive the return light of the pole piece, and obtain the wavelength of the return light, and search for the pole piece thickness data corresponding to the wavelength of the light in a preset wavelength relationship table, wherein the preset wavelength relationship table includes the correspondence between the wavelength of the light and the pole piece thickness data.

Images