Ductility monitoring system and method

Abstract

The application relates to the technical field of batteries, and discloses a system and a method for monitoring elongation, which comprises a roller for rolling an electrode sheet, the electrode sheet moving along a tape running direction, an encoder for triggering a pulse when the electrode sheet moves, a first detection module for collecting a pre-rolling image of the electrode sheet in response to the pulse, a second detection module for collecting a post-rolling image of the electrode sheet in response to the pulse, and a control module for aligning the pre-rolling image and the post-rolling image, and calculating a first elongation of the electrode sheet in a direction perpendicular to the tape running direction according to the aligned images. The application ensures that the two detection modules are synchronously detected through the pulse triggered by the encoder when the electrode sheet moves, and ensures that the pre-rolling and post-rolling states of the same region of the electrode sheet are shot through image frame alignment, so that the first elongation of the electrode sheet can be calculated without marking the electrode sheet, the first elongation monitoring cost is reduced, and the electrode sheet is not damaged.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to an elongation monitoring system and method. Background Technology

[0002] Currently, the rolling elongation rate of the electrode sheet in the horizontal direction (perpendicular to the electrode sheet's belt direction) is an important parameter to ensure the consistency of battery cell production. It serves as an input parameter for key indicators such as the cell balance (CB) value and compaction. Real-time monitoring of the rolling elongation rate of the electrode sheet can effectively prevent batch problems in battery cells.

[0003] However, the relevant elongation monitoring methods usually require marking on the electrode and calculating the elongation based on the change in the film area at the marked location, which incurs additional marking costs and may also damage the electrode. Summary of the Invention

[0004] In view of the above problems, the present invention provides an elongation monitoring system and method, which aims to solve the problem that the relevant elongation monitoring methods usually require marking on the electrode and calculating the elongation based on the change of the film area at the marked position, which results in additional marking costs and may also damage the electrode.

[0005] In a first aspect, the present invention provides an elongation monitoring system, the elongation monitoring system comprising: a first detection module, a roll, a second detection module, an encoder, and a control module;

[0006] The roller is used to roll and press the electrode sheet, which moves along the belt conveyor direction. The first detection module is located on one side of the roller, and the second detection module is located on the other side of the roller.

[0007] The encoder is used to trigger pulses when the pole piece moves;

[0008] The first detection module is used to respond to the pulse, acquire an image of the electrode before rolling, and send the image to the control module.

[0009] The second detection module is used to respond to the pulse, acquire the rolled image of the electrode sheet, and send the rolled image to the control module;

[0010] The control module is used to perform image frame alignment on the pre-rolling image and the post-rolling image, and to calculate the first elongation rate of the electrode in the direction perpendicular to the belt conveyor based on the aligned pre-rolling image and the aligned post-rolling image. The image frame alignment is used to ensure that the image acquisition area of ​​the aligned pre-rolling image and the image acquisition area of ​​the aligned post-rolling image correspond to the same area of ​​the electrode.

[0011] In the technical solution of this invention, the pulses triggered by the encoder when the electrode moves ensure that the two detection modules detect synchronously, and the image frame alignment ensures that the two detection modules capture the same area of ​​the electrode before and after rolling. Therefore, the first elongation of the electrode in the direction perpendicular to the belt can be calculated without marking on the electrode, thereby reducing the cost of monitoring the first elongation and avoiding damage to the electrode.

[0012] In some embodiments, the control module is further configured to obtain the actual interval distance between the first detection module and the second detection module, and to obtain the actual shooting area length corresponding to a single image, wherein an integer multiple of the actual shooting area length is the actual interval distance;

[0013] The control module is also used to obtain the total number of pulses required to capture a single image;

[0014] The control module is also used to calculate the number of interval pulses between the first detection module and the second detection module when they capture the same area of ​​the electrode sheet based on the actual interval distance, the actual shooting area length, and the total number of pulses;

[0015] The control module is also used to perform image frame alignment between the pre-rolling image and the post-rolling image based on the number of interval pulses.

[0016] In the technical solution of this invention embodiment, the number of interval pulses between the first detection module and the second detection module in the same area of ​​the electrode film captured by the first detection module and the second detection module is calculated based on the actual interval distance between the first detection module and the second detection module, the actual shooting area length corresponding to a single image, and the total number of pulses required to shoot a single image. This can improve the accuracy of the number of interval pulses, thereby providing a precise timing basis for image frame alignment and ensuring that the images before and after cold pressing can accurately match the same area.

[0017] In some embodiments, the first detection module and the second detection module are line scan cameras;

[0018] The control module is further configured to obtain the single-pixel accuracy of the first detection module and the second detection module and the number of pulses required to trigger the shooting of a single row of pixels, wherein the single-pixel accuracy represents the actual physical length corresponding to a single row of pixels;

[0019] The control module is also used to calculate the total number of pulses required to capture a single image based on the number of pulses, the single pixel accuracy, and the actual shooting area length.

[0020] In the technical solution of this invention embodiment, the total number of pulses required to capture a single image is calculated by the single-pixel accuracy of the first detection module and the second detection module, the number of pulses required to trigger the capture of a single row of pixels, and the actual capture area length. This provides quantitative parameters for calculating the pulse interval between the cameras capturing the same area before and after cold pressing, ensuring the accuracy of frame alignment.

[0021] In some embodiments, the single-pixel accuracy is less than a preset threshold, wherein the preset threshold is predetermined based on the measurement elongation accuracy.

[0022] In the technical solution of this invention embodiment, by setting the single pixel accuracy to be less than a preset threshold, wherein the preset threshold is predetermined based on the measurement elongation accuracy, it is possible to ensure that the width measurement error before and after cold pressing of the electrode sheet is within the allowable range, providing high-precision raw data for the calculation of the first elongation, thereby meeting the accuracy requirements of the process for online monitoring of elongation, and thus avoiding measurement deviations caused by insufficient pixel accuracy, ensuring cell consistency.

[0023] In some embodiments, the control module is further configured to obtain a first film width of multiple regions in the image before alignment and roll pressing, and to obtain a second film width of the same region in the image after alignment and roll pressing.

[0024] The control module is also used to calculate the elongation of each region based on the first film width and the second film width;

[0025] The control module is also used to calculate the first elongation of the electrode in the direction perpendicular to the tape delivery based on the elongation of each region.

[0026] In the technical solution of this invention, the elongation rate of each region is first calculated based on the first film width of multiple regions in the image before alignment and before rolling, and the second film width of the same region in the image after alignment and after rolling. Then, the first elongation rate of the electrode sheet in the direction perpendicular to the conveyor belt is calculated based on the elongation rate of each region. This can reflect the overall cold pressing elongation level of the electrode sheet, avoid misjudgment caused by the partiality of local data, provide a global reference for the closed-loop control of the cold pressing equipment, ensure the consistency of the entire roll of electrode sheet, and reduce the risk of batch defects.

[0027] In some embodiments, the first detection module and the second detection module are large field-of-view macro cameras, the field of view of the large field-of-view macro camera is greater than the width of the electrode, and the working distance of the large field-of-view macro camera is less than a preset distance.

[0028] In the technical solution of this invention embodiment, by setting the first detection module and the second detection module as a large field-of-view macro camera, the field of view of the large field-of-view macro camera is larger than the width of the electrode sheet, and the working distance of the large field-of-view macro camera is smaller than the preset distance, thereby adapting to the compact space of the electrode sheet production line, facilitating installation and maintenance, and ensuring that the image edges are not distorted.

[0029] In some embodiments, the elongation monitoring system further includes a third detection module and a fourth detection module, wherein the third detection module is disposed on one side of the roll and the fourth detection module is disposed on the other side of the roll.

[0030] The third detection module is used to respond to the pulse, collect the belt speed before the rolling of the electrode sheet, and send the belt speed before the rolling to the control module;

[0031] The fourth detection module is used to respond to the pulse, collect the belt speed after the electrode is rolled, and send the belt speed after the roller is rolled to the control module;

[0032] The control module is used to calculate the second elongation of the electrode sheet in the belt-carrying direction based on the belt-carrying speed before and after the roll-pressing.

[0033] In the technical solution of this invention, a third detection module and a fourth detection module are respectively set on both sides of the roll. The third detection module and the fourth detection module detect the belt speed before and after the roll pressing of the electrode sheet, respectively. The second elongation of the electrode sheet in the belt pressing direction is calculated based on the belt speed before and after the roll pressing. Therefore, the second elongation of the electrode sheet in the belt pressing direction can be calculated without marking on the electrode sheet, thereby reducing the detection cost of the second elongation and avoiding damage to the electrode sheet.

[0034] In some embodiments, the third detection module is further configured to simultaneously emit a first interference laser and a second interference laser toward the electrode in response to the pulse, wherein the first interference laser and the second interference laser form a first Newton's ring on the electrode;

[0035] The third detection module is further configured to obtain the width of the first Newton's rings, calculate the pre-rolling speed of the electrode based on the width of the first Newton's rings, the angle between the first interference laser and the second interference laser, and the detection frequency of the third detection module, and send the pre-rolling speed to the control module.

[0036] In the technical solution of this invention embodiment, by simultaneously emitting a first interference laser and a second interference laser onto the electrode, and calculating the belt speed of the electrode before rolling based on the first Newton's rings formed on the electrode by the first and second interference lasers using a preset algorithm, the measurement accuracy of the belt speed before rolling can be improved, thereby further improving the accuracy of the second elongation rate.

[0037] In some embodiments, the fourth detection module is further configured to simultaneously emit a third interference laser and a fourth interference laser toward the electrode in response to the pulse, wherein the third interference laser and the fourth interference laser form a second Newton's ring on the electrode;

[0038] The fourth detection module is further configured to obtain the width of the second Newton's rings, calculate the belt speed of the electrode after rolling based on the width of the second Newton's rings, the angle between the third interference laser and the fourth interference laser, and the detection frequency of the fourth detection module, and send the belt speed after rolling to the control module.

[0039] In the technical solution of this invention embodiment, by simultaneously emitting a third interference laser and a fourth interference laser onto the electrode, and calculating the belt speed of the electrode after rolling based on the second Newton's rings formed on the electrode by the third and fourth interference lasers using a preset algorithm, the measurement accuracy of the belt speed after rolling can be improved, thereby further improving the accuracy of the second elongation rate.

[0040] In some embodiments, the third detection module and the fourth detection module are arranged perpendicular to the electrode, and the angles between the first interference laser and the electrode, the second interference laser and the electrode, the third interference laser and the electrode, and the fourth interference laser and the electrode are all 90 degrees.

[0041] In the technical solution of this invention embodiment, the third detection module and the fourth detection module are set perpendicular to the electrode, and the sensor emits a laser at an angle of 90° with the electrode, thereby avoiding other velocity components from affecting the calculation of the second elongation, and thus further improving the accuracy of the second elongation.

[0042] In some embodiments, the elongation monitoring system further includes: a first heat dissipation module corresponding to the third detection module and a second heat dissipation module corresponding to the fourth detection module;

[0043] The first heat dissipation module is used to isolate the heat generated by the electrode rolling process from the third detection module and / or to dissipate heat from the third detection module;

[0044] The second heat dissipation module is used to isolate the heat generated by the electrode rolling process from the fourth detection module and / or to dissipate heat from the fourth detection module.

[0045] In the technical solution of this invention embodiment, the elongation monitoring system further includes: a first heat dissipation module corresponding to the third detection module and a second heat dissipation module corresponding to the fourth detection module. The heat dissipation module dissipates heat from the detection module by isolating heat and / or dissipating heat, thereby isolating the heat of the roll and reducing the interference of the heat generated during the electrode rolling process on the third and fourth detection modules, thereby improving the accuracy of speed measurement.

[0046] In some embodiments, the control module is further configured to calculate the pre-rolling film width of the electrode sheet in the direction perpendicular to the belt feed based on the pre-rolling image, and to calculate the post-rolling film width of the electrode sheet in the direction perpendicular to the belt feed based on the post-rolling image.

[0047] The control module is also used to calculate the length of the electrode sheet before rolling in the belt-carrying direction based on the belt-carrying speed before rolling, and to calculate the length of the electrode sheet after rolling in the belt-carrying direction based on the belt-carrying speed after rolling.

[0048] The control module is also used to calculate the surface elongation of the electrode sheet based on the film width before rolling, the film width after rolling, the length before rolling, and the length after rolling.

[0049] In the technical solution of this invention embodiment, the film width of the electrode sheet before and after rolling is first calculated based on the images before and after rolling, respectively, in the direction perpendicular to the belt feeding direction. Then, the length of the electrode sheet before and after rolling is calculated based on the belt feeding speed before and after rolling. Finally, the surface elongation of the electrode sheet is calculated based on the film width and length before and after rolling, thereby enabling the calculation of the surface elongation of the electrode sheet and better reflecting the consistency of battery cell production.

[0050] In some embodiments, the elongation monitoring system further includes: a rolling mill main unit;

[0051] The control module is further configured to send the elongation rate to the rolling host, wherein the elongation rate includes at least one of the first elongation rate, the second elongation rate, and the surface elongation rate;

[0052] The rolling mill host is used to calculate the adjustment amount of the rolling mill based on the elongation rate, and adjust the rolling pressure parameters of the rolling mill based on the adjustment amount.

[0053] In the technical solution of this invention embodiment, the elongation monitoring system further includes: a roll host, which calculates the adjustment amount of the roll based on the elongation and adjusts the roll pressing parameters of the roll based on the adjustment amount, thereby enabling real-time optimization of the roll pressing parameters of the roll, so that the elongation of the electrode sheet returns to the qualified range, thereby reducing the number of electrode sheets with poor elongation from the source, avoiding batch events, and forming a closed loop.

[0054] In some embodiments, the rolling mill host is further configured to calculate the difference between the elongation rate and a preset elongation rate threshold, and to calculate the adjustment amount of the rolling mill based on the elongation rate difference;

[0055] The rolling mill host is also used to adjust the rolling pressure parameters of the rolling mill according to the adjustment amount and a preset adjustment step.

[0056] In the technical solution of this invention, the adjustment amount of the roll is calculated based on the difference between the elongation rate and the preset elongation rate threshold, thereby improving the accuracy of the adjustment amount. Furthermore, the roll pressure parameters of the roll are adjusted according to the preset adjustment step based on the adjustment amount, thereby avoiding over-adjustment and reducing elongation rate fluctuations.

[0057] In some embodiments, the rolls include: a first roll and a second roll, wherein the first roll and the second roll are disposed correspondingly;

[0058] The rolling mill host is also used to obtain the current rolling angle of the first rolling mill and / or the second rolling mill;

[0059] The rolling mill host is also used to calculate the adjustment amount of the rolling angle of the second roll and / or the first roll based on the elongation and the current rolling angle.

[0060] In the technical solution of this invention embodiment, the rolls include: a first roll and a second roll. The roll angle of the second roll and / or the first roll can be adjusted according to the elongation and the current roll angle of the first roll and / or the second roll, thereby achieving precise local pressure control in the width direction, thus avoiding the problem of uneven regional elongation caused by overall pressure adjustment, and improving the consistency of the elongation of the entire electrode.

[0061] In some embodiments, the elongation monitoring system further includes: a display module;

[0062] The control module is also used to send the elongation rate to the display module;

[0063] The display module is used to receive the stretch rate sent by the control module and display the stretch rate.

[0064] In the technical solution of this invention embodiment, the elongation monitoring system further includes a display module, which receives the elongation rate sent by the control module and displays the elongation rate, thereby enabling operators to monitor the cold pressing elongation status of the electrode sheet in real time and promptly detect out-of-tolerance areas.

[0065] In some embodiments, the elongation monitoring system further includes: an alarm module;

[0066] The control module is also used to send an alarm command to the alarm module when the elongation does not meet the preset specifications;

[0067] The alarm module is used to stop the rolling process according to the alarm command and generate a prompt message corresponding to the alarm command.

[0068] In the technical solution of this invention embodiment, the elongation monitoring system further includes an alarm module. The alarm module stops rolling according to the alarm command and generates prompt information corresponding to the alarm command, thereby enabling automatic identification of abnormalities and command triggering, avoiding the lag and misjudgment of manual judgment, ensuring the timeliness and accuracy of alarm actions, and buying time for subsequent shutdown and processing, thereby reducing the risk of batch defects from a mechanism perspective.

[0069] In some embodiments, the elongation monitoring system further includes: an encoding roller corresponding to the encoder;

[0070] The encoder roller is used to rotate in response to the movement of the electrode sheet, and the rotation of the encoder roller drives the encoder to trigger pulses.

[0071] In the technical solution of this invention embodiment, the elongation monitoring system further includes: an encoder roller corresponding to the encoder, which rotates when the electrode moves, and the rotation of the encoder roller drives the encoder to trigger pulses, thereby ensuring that the pulse signal can truly reflect the actual moving distance of the electrode, and providing an accurate timing reference for subsequent synchronous image acquisition by the camera and image frame alignment.

[0072] In some embodiments, the encoding roller is an active roller;

[0073] The active roller is used to drive the electrode sheet to move by actively rotating, and to drive the encoder to trigger pulses.

[0074] In the technical solution of this invention embodiment, the encoding roller is an active roller; the active roller drives the electrode to move by actively rotating, and drives the encoder to trigger pulses, thereby reducing the relative slippage between the electrode and the roller body, so that the rotation angle of the encoding roller strictly corresponds to the actual moving distance of the electrode, ensuring the accuracy of the encoder pulse signal, and avoiding the deviation between the number of pulses and the actual moving distance caused by slippage.

[0075] Secondly, the present invention provides a method for monitoring elongation, comprising:

[0076] Roll-pressed electrode sheets, which move along the belt conveyor direction;

[0077] A pulse is triggered when the electrode moves;

[0078] In response to multiple pulses, an image of the electrode sheet before rolling is acquired;

[0079] In response to multiple pulses, images of the electrode sheet after rolling are acquired;

[0080] Image frames are aligned between the pre-rolling image and the post-rolling image, and a first elongation of the electrode in the direction perpendicular to the belt conveyor is calculated based on the aligned pre-rolling image and the aligned post-rolling image. The image frame alignment is used to ensure that the image acquisition area of ​​the aligned pre-rolling image and the image acquisition area of ​​the aligned post-rolling image correspond to the same area of ​​the electrode.

[0081] In the technical solution of this invention, synchronous detection is ensured by triggering pulses when the electrode moves, and the state before and after rolling of the same area of ​​the electrode is ensured by image frame alignment. Thus, the first elongation of the electrode in the direction perpendicular to the belt can be calculated without marking on the electrode, thereby reducing the cost of monitoring the first elongation and avoiding damage to the electrode.

[0082] In some embodiments, the image frame alignment of the pre-rolling image and the post-rolling image includes:

[0083] The actual interval distance between the acquisition position of the image before rolling and the acquisition position of the image after rolling is obtained, and the actual shooting area length corresponding to a single image is obtained, wherein an integer multiple of the actual shooting area length is the actual interval distance;

[0084] Obtain the total number of pulses required to capture a single image;

[0085] The number of interval pulses between the first detection module corresponding to the image before rolling and the second detection module corresponding to the image after rolling is calculated based on the actual interval distance, the actual shooting area length, and the total number of pulses.

[0086] Image frames are aligned between the pre-rolling and post-rolling images based on the number of interval pulses.

[0087] In the technical solution of this invention, the number of interval pulses between the acquisition positions of the image before and after rolling is calculated based on the actual interval distance between the acquisition positions of the image before and after rolling, the actual shooting area length corresponding to a single image, and the total number of pulses required to capture a single image. This improves the accuracy of the interval pulse count and provides a precise timing basis for image frame alignment, ensuring that the images before and after cold pressing can accurately match the same area.

[0088] In some embodiments, obtaining the total number of pulses required to capture a single image includes:

[0089] The single-pixel precision and the number of pulses required to trigger the capture of a single row of pixels are obtained for capturing the images before and after the rolling process, wherein the single-pixel precision represents the actual physical length corresponding to a single row of pixels;

[0090] The total number of pulses required to capture a single image is calculated based on the pulse count, the single-pixel precision, and the actual shooting area length.

[0091] In the technical solution of this invention embodiment, the total number of pulses required to shoot a single image is calculated by using the single-pixel accuracy of the image before and after rolling, the number of pulses required to trigger the shooting of a single row of pixels, and the actual shooting area length. This provides quantitative parameters for calculating the pulse interval for the cameras shooting the same area before and after cold pressing, ensuring the accuracy of frame alignment.

[0092] In some embodiments, calculating the first elongation of the electrode sheet in the direction perpendicular to the conveyor belt based on the pre-alignment and post-alignment images includes:

[0093] Obtain the first film width of multiple regions in the image before alignment and roll pressing, and obtain the second film width of the same region in the image after alignment and roll pressing;

[0094] Calculate the elongation of each region based on the first film width and the second film width;

[0095] The first elongation of the electrode in the direction perpendicular to the travel strip is calculated based on the elongation of each region.

[0096] In the technical solution of this invention, the elongation rate of each region is first calculated based on the first film width of multiple regions in the image before alignment and before rolling, and the second film width of the same region in the image after alignment and after rolling. Then, the first elongation rate of the electrode sheet in the direction perpendicular to the conveyor belt is calculated based on the elongation rate of each region. This can reflect the overall cold pressing elongation level of the electrode sheet, avoid misjudgment caused by the partiality of local data, provide a global reference for the closed-loop control of the cold pressing equipment, ensure the consistency of the entire roll of electrode sheet, and reduce the risk of batch defects.

[0097] In some embodiments, after triggering the pulse when the electrode moves, the method further includes:

[0098] In response to the pulse, the belt speed before the electrode is rolled is acquired;

[0099] In response to the pulse, the belt speed of the electrode sheet after rolling is collected;

[0100] The second elongation of the electrode sheet in the belt-carrying direction is calculated based on the belt-carrying speed before and after the roll forming.

[0101] In the technical solution of this invention, the second elongation of the electrode in the belt-carrying direction is calculated by detecting the belt-carrying speed before and after the rolling of the electrode, and calculating the second elongation of the electrode in the belt-carrying direction based on the belt-carrying speed before and after the rolling. Therefore, the second elongation of the electrode in the belt-carrying direction can be calculated without marking the electrode, thereby reducing the detection cost of the second elongation and avoiding damage to the electrode.

[0102] In some embodiments, the step of acquiring the belt speed before rolling the electrode sheet in response to the pulse includes:

[0103] In response to the pulse, a first interference laser and a second interference laser are simultaneously emitted toward the electrode, wherein the first interference laser and the second interference laser form a first Newton's ring on the electrode;

[0104] The width of the first Newton's rings is obtained, and the rolling speed of the electrode is calculated based on the width of the first Newton's rings, the angle between the first interference laser and the second interference laser, and the detection frequency of the rolling speed.

[0105] In the technical solution of this invention embodiment, by simultaneously emitting a first interference laser and a second interference laser onto the electrode, and calculating the belt speed of the electrode before rolling based on the first Newton's rings formed on the electrode by the first and second interference lasers using a preset algorithm, the measurement accuracy of the belt speed before rolling can be improved, thereby further improving the accuracy of the second elongation rate.

[0106] In some embodiments, the step of acquiring the belt speed of the electrode after rolling in response to the pulse includes:

[0107] In response to the pulse, a third interference laser and a fourth interference laser are simultaneously emitted toward the electrode, wherein the third interference laser and the fourth interference laser form a second Newton's ring on the electrode;

[0108] The width of the second Newton's rings is obtained, and the rolling speed of the electrode is calculated based on the width of the second Newton's rings, the angle between the third and fourth interference lasers, and the detection frequency of the rolling speed.

[0109] In the technical solution of this invention embodiment, by simultaneously emitting a third interference laser and a fourth interference laser onto the electrode, and calculating the belt speed of the electrode after rolling based on the second Newton's rings formed on the electrode by the third and fourth interference lasers using a preset algorithm, the measurement accuracy of the belt speed after rolling can be improved, thereby further improving the accuracy of the second elongation rate.

[0110] In some embodiments, after calculating the first elongation of the electrode sheet in the direction perpendicular to the belt conveyor based on the pre-alignment and post-alignment images, the method further includes:

[0111] The pre-rolling film width of the electrode sheet in the direction perpendicular to the belt feed is calculated based on the pre-rolling image, and the post-rolling film width of the electrode sheet in the direction perpendicular to the belt feed is calculated based on the post-rolling image.

[0112] The length of the electrode sheet before rolling in the belt-carrying direction is calculated based on the belt-carrying speed before rolling, and the length of the electrode sheet after rolling in the belt-carrying direction is calculated based on the belt-carrying speed after rolling.

[0113] The surface elongation of the electrode sheet is calculated based on the film width before rolling, the film width after rolling, the length before rolling, and the length after rolling.

[0114] In the technical solution of this invention embodiment, the film width of the electrode sheet before and after rolling is first calculated based on the images before and after rolling, respectively, in the direction perpendicular to the belt feeding direction. Then, the length of the electrode sheet before and after rolling is calculated based on the belt feeding speed before and after rolling. Finally, the surface elongation of the electrode sheet is calculated based on the film width and length before and after rolling, thereby enabling the calculation of the surface elongation of the electrode sheet and better reflecting the consistency of battery cell production.

[0115] In some embodiments, after calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length, the method further includes:

[0116] The adjustment amount during the rolling of the electrode sheet is calculated based on the elongation rate, wherein the elongation rate includes at least one of the first elongation rate, the second elongation rate, and the surface elongation rate;

[0117] Adjust the rolling pressure parameters when rolling the electrode sheet according to the adjustment amount.

[0118] In the technical solution of this invention embodiment, the adjustment amount of the roll is calculated based on the elongation rate, and the roll pressure parameters of the roll are adjusted according to the adjustment amount to optimize the roll pressure parameters of the roll in real time, so that the elongation rate of the electrode sheet returns to the qualified range. This enables the roll pressure parameters of the roll to be optimized in real time, so that the elongation rate of the electrode sheet returns to the qualified range, thereby reducing the number of electrode sheets with poor elongation rate from the source, avoiding batch events, and forming a closed loop.

[0119] In some embodiments, calculating the adjustment amount when rolling the electrode sheet based on the elongation includes:

[0120] Calculate the difference between the elongation rate and the preset elongation rate threshold;

[0121] The adjustment amount during electrode rolling is calculated based on the difference in elongation.

[0122] In the technical solution of this invention, the adjustment amount of the roll is calculated based on the difference between the elongation rate and the preset elongation rate threshold, thereby improving the accuracy of the adjustment amount. Furthermore, the roll pressure parameters of the roll are adjusted according to the preset adjustment step based on the adjustment amount, thereby avoiding over-adjustment and reducing elongation rate fluctuations.

[0123] In some embodiments, calculating the adjustment amount when rolling the electrode sheet based on the elongation includes:

[0124] Obtain the current rolling angle of the rolls that roll the electrode sheet;

[0125] The roll angle adjustment amount is calculated based on the elongation and the current roll angle.

[0126] In the technical solution of this invention embodiment, the rolling angle adjustment amount of the rolling mill is calculated based on the current rolling angle of the rolling mill of the electrode sheet and the elongation and the current rolling angle, thereby realizing precise local pressure control in the width direction, thus avoiding the problem of uneven regional elongation caused by overall pressure adjustment and improving the consistency of the elongation of the entire electrode sheet.

[0127] In some embodiments, after calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length, the method further includes:

[0128] If the elongation does not meet the preset specifications, an alarm command is generated;

[0129] The rolling process is stopped according to the alarm command, and a prompt message corresponding to the alarm command is generated.

[0130] In the technical solution of this invention embodiment, the rolling is stopped according to the alarm command, and the prompt information corresponding to the alarm command is generated, thereby realizing the automatic identification of abnormalities and command triggering, avoiding the lag and misjudgment of manual judgment, ensuring the timeliness and accuracy of alarm action, and buying time for subsequent shutdown and processing, thereby reducing the risk of batch defects from a mechanism perspective.

[0131] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0132] Figure 1 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0133] Figure 2 These are front and rear side views of the electrode rolling process in some embodiments of the present invention;

[0134] Figure 3 These are top views of the electrode rolling process in some embodiments of the present invention;

[0135] Figure 4 These are schematic diagrams of membrane widths according to some embodiments of the present invention;

[0136] Figure 5 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0137] Figure 6 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0138] Figure 7 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0139] Figure 8 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0140] Figure 9 These are schematic diagrams of the display module interface according to some embodiments of the present invention;

[0141] Figure 10 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0142] Figure 11 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention;

[0143] Figure 12 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention;

[0144] Figure 13 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention;

[0145] Figure 14 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention;

[0146] Figure 15 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention;

[0147] Figure 16 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention;

[0148] Figure 17 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention;

[0149] Figure 18 This is a flowchart of a gap elongation monitoring and correction method according to some embodiments of the present invention.

[0150] The reference numerals in the detailed embodiments are as follows:

[0151] First detection module 10, roll 20, second detection module 30, encoder 40, control module 50, third detection module 60, fourth detection module 70, roll main unit 80, first roll 21, second roll 22, encoder roll 41, display module 90, alarm module 100. Detailed Implementation

[0152] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0153] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0154] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0155] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0156] In the description of the embodiments of this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0157] In the description of the embodiments of the present invention, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0158] In the description of the embodiments of the present invention, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0159] In the description of the embodiments of this invention, unless otherwise explicitly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this invention according to the specific circumstances. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0160] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0161] In the battery electrode production process, the rolling elongation rate of the electrode in the horizontal direction (perpendicular to the electrode belt direction) is an important parameter to ensure the consistency of the produced cells. It serves as an input parameter for key indicators such as cell balance (CB) value and compaction. Real-time monitoring of the rolling elongation rate of the electrode can effectively prevent batch problems in the cells.

[0162] The relevant elongation monitoring methods usually include the following two types: one is offline manual measurement, and the other is online marking measurement. Offline measurement cannot escape the problems of wasting electrode sheets, inaccurate measurement, and inability to characterize the overall elongation of the material. The specific defects are: (1) The entire experimental process is manual; (2) The manual reading error is large and the accuracy cannot meet the requirements of elongation; (3) Manual statistical data is prone to data omission and has poor feasibility; (4) After cold pressing, the electrode sheets are taken out, resulting in waste material, large loss of yield, and unacceptable to the production line; (5) Offline measurement is time-consuming and labor-intensive and cannot effectively characterize the elongation of the entire roll of material. Online marking measurement has problems such as marking cost and marking damage to the electrode sheets. The specific defects are: (1) Laser marking damages the electrode sheets and is prone to causing risks such as inner ring crack and corner lithium plating in the later stage; (2) Local measurement cannot characterize the overall film width elongation change; (3) The laser is expensive. Therefore, the relevant elongation monitoring methods usually require marking on the electrode and calculating the elongation based on the change in the film area at the marked position, which incurs additional marking costs and may also damage the electrode. This is a technical problem that urgently needs to be solved.

[0163] To address the issue that traditional methods of elongation monitoring typically require marking the electrode and calculating the elongation based on changes in the film area at the marked location, which incurs additional marking costs and may damage the electrode, a new approach can be adopted. This involves using an encoder to trigger pulses as the electrode moves to ensure synchronous detection by two detection modules. Furthermore, image frame alignment ensures that both detection modules capture the same area of ​​the electrode before and after rolling. This eliminates the need for marking the electrode and allows for the calculation of the first elongation in the direction perpendicular to the belt conveyor, thereby reducing the cost of first elongation monitoring and preventing damage to the electrode.

[0164] In some embodiments, an elongation monitoring system is provided, comprising: a first detection module, a roll, a second detection module, an encoder, and a control module; the roll is used to roll an electrode sheet, the electrode sheet moving along the belt feed direction; the first detection module is disposed on one side of the roll, and the second detection module is disposed on the other side of the roll; the encoder is used to trigger a pulse when the electrode sheet moves; the first detection module is used to, in response to the pulse, acquire an image of the electrode sheet before rolling and send the image of the electrode sheet before rolling to the control module; the second detection module is used to, in response to the pulse, acquire an image of the electrode sheet after rolling and send the image of the electrode sheet after rolling to the control module; the control module is used to perform image frame alignment on the image of the electrode sheet before rolling and the image of the electrode sheet after rolling, and calculate a first elongation of the electrode sheet in the direction perpendicular to the belt feed direction based on the aligned image of the electrode sheet before rolling and the aligned image of the electrode sheet after rolling, wherein the image frame alignment is used to ensure that the image acquisition area of ​​the aligned image of the electrode sheet before rolling and the image acquisition area of ​​the aligned image of the electrode sheet after rolling correspond to the same area of ​​the electrode sheet.

[0165] To reduce the cost of elongation monitoring and avoid damage to the electrode, this embodiment uses pulses triggered by the encoder when the electrode moves to ensure that the two detection modules detect synchronously, and uses image frame alignment to ensure that the two detection modules capture the same area of ​​the electrode before and after rolling.

[0166] The elongation monitoring system refers to a system used for online real-time monitoring of the elongation of lithium battery electrodes after cold pressing. Through non-destructive testing, full-area coverage, synchronous alignment, and closed-loop control, it achieves precise measurement and control of the electrode elongation. Machine Direction (MD) refers to the direction of electrode movement on the production line, perpendicular to the horizontal direction (TD). The first detection module refers to a detection device located on one side of the rolls, specifically a large-field-of-view macro camera before cold pressing, used to acquire images of the electrode before cold pressing. The rolls refer to cold pressing rolls, used to cold press the electrodes; they are the core equipment for electrode deformation (elongation), and their pressure can be adjusted to correct the elongation. The second detection module refers to a detection device located on the other side of the rolls, specifically a macro camera after cold pressing, operating in the same way as the first detection module, used to acquire images of the electrode after cold pressing. The encoder generates pulse signals when the electrode moves, providing synchronous trigger signals for the first and second detection modules, ensuring that the time and position of the acquired images are matched. The control module is responsible for receiving image data from the first and second detection modules, performing image frame alignment, and calculating the elongation rate. The first elongation rate can refer to the elongation rate of the electrode in the direction perpendicular to the conveyor belt, that is, the elongation rate of the electrode in the TD direction.

[0167] For ease of understanding, please refer to Figure 1 , Figure 2 as well as Figure 3 This explanation is provided, but does not limit the scope of this application. Figure 1 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention. Figure 2 These are front and rear side views of the electrode rolling process according to some embodiments of the present invention. Figure 3 These are top views of the electrode roll forming process before and after some embodiments of the present invention. As an example, such as... Figure 1 and Figure 2 As shown, the roller 20 presses the electrode sheet, causing it to extend and move along the belt conveyor direction. This movement triggers the encoder 40 to emit a pulse signal. This same pulse signal is split into two and sent to the first detection module 10 and the second detection module 30 respectively, ensuring that the first detection module 10 and the second detection module 30 take pictures synchronously. Since the first detection module 10 and the second detection module 30 are located on opposite sides of the roller 20, the images obtained when they take pictures synchronously are not of the same area of ​​the electrode sheet. To overcome the aforementioned shortcomings, this embodiment uses frame alignment to ensure that the two detection modules capture the same area of ​​the electrode sheet before and after rolling. The specific steps of frame alignment are as follows: the control module 50 obtains the interval pulse number M between the first detection module 10 and the second detection module 30 capturing the same area of ​​the electrode sheet (i.e., the encoder 40 generates pulses when the same area of ​​the electrode sheet moves from the image acquisition position corresponding to the first detection module 10 to the image acquisition position corresponding to the second detection module 30). The currently captured image after rolling is used as the aligned image after rolling, and the image before rolling captured M pulses prior is used as the image before rolling corresponding to the aligned image after rolling. The interval pulse number M can be preset or calculated based on the actual parameters of the elongation monitoring system; this embodiment does not impose any restrictions on this. Figure 3 As shown, after obtaining the alignment before rolling image and the alignment after rolling image, the control module 50 calculates the pre-rolling film width D of the electrode in the direction perpendicular to the belt feed direction using image recognition technology based on the pre-rolling image, and calculates the post-rolling film width D' of the electrode in the direction perpendicular to the belt feed direction based on the post-rolling image. It then calculates the first elongation δ of the electrode in the direction perpendicular to the belt feed direction based on the pre-rolling and post-rolling film widths. D The specific calculation formula is δ D =(D'-D) / D*100%, where δ D D represents the first elongation of the electrode in the direction perpendicular to the belt travel, D represents the film width before rolling, and D' represents the film width after rolling.

[0168] This embodiment ensures synchronous detection by two detection modules through pulses triggered by the encoder when the electrode moves, and ensures that the two detection modules capture the same area of ​​the electrode before and after rolling by image frame alignment. Therefore, the first elongation of the electrode in the direction perpendicular to the belt can be calculated without marking on the electrode, thereby reducing the cost of monitoring the first elongation and avoiding damage to the electrode.

[0169] In some embodiments, the control module is further configured to obtain the actual interval distance between the first detection module and the second detection module, and obtain the actual shooting area length corresponding to a single image, wherein an integer multiple of the actual shooting area length is the actual interval distance; the control module is further configured to obtain the total number of pulses required to shoot a single image; the control module is further configured to calculate the interval pulse number of the first detection module and the second detection module shooting the same area of ​​the electrode sheet according to the actual interval distance, the actual shooting area length and the total number of pulses; the control module is further configured to perform image frame alignment on the image before rolling and the image after rolling according to the interval pulse number.

[0170] To improve the accuracy of the interval pulse count and provide precise timing data for image frame alignment, ensuring that images before and after cold pressing accurately match the same area, this embodiment calculates the interval pulse count for the same area of ​​the electrode captured by the first and second detection modules based on the actual interval distance between the first and second detection modules, the actual shooting area length corresponding to a single image, and the total number of pulses required to capture a single image.

[0171] The actual interval distance can refer to the actual length of the electrode in the belt-carrying direction between the first acquisition position of the first detection module and the second acquisition position of the second detection module (i.e., the true distance between the electrodes between the two acquisition points, denoted as L0). The actual acquisition area length corresponding to a single image can refer to the actual length of the electrode covered by a single image in the belt-carrying direction (i.e., the physical length of the electrode in the belt-carrying direction contained in an image, denoted as L1). The total number of pulses can refer to the total number of pulses generated by the encoder to trigger the acquisition of a single image (i.e., the number of pulses output by the encoder during the acquisition of an image, denoted as P). The interval pulse count can refer to the difference in the number of pulses generated by the encoder when the first detection module acquires an image of a certain area and when the second detection module acquires an image of the same area (i.e., the number of pulses generated by the encoder when the same area of ​​the electrode moves from the first acquisition position corresponding to the first detection module to the second acquisition position corresponding to the second detection module, denoted as M).

[0172] In the specific implementation, the actual distance between the camera before and after cold pressing in the electrode transport direction is determined by physical measurement (such as laser ranging), i.e., the actual interval distance L0. To provide basic geometric parameters for subsequent image frame alignment and ensure that images of the same area of ​​the electrode before and after cold pressing can be associated through an integer multiple of the number of images, avoiding regional misalignment due to distance mismatch, in this embodiment, the actual length L1 of the electrode covered by a single image in the transport direction is set, and L1 is adjusted so that L0 is an integer multiple of L1 (i.e., L0 = N * L1, where N is a positive integer, ensuring that when the same area of ​​the electrode moves from the first acquisition position to the second acquisition position, it is exactly completely covered by N images). The total number of pulses P required to capture a single image is obtained. The total number of pulses P can be preset or calculated based on the actual parameters of the elongation monitoring system; this embodiment does not impose any restrictions on this. Since the interval pulse number M is the total number of pulses generated by the encoder when the same area of ​​the electrode moves from the first acquisition position to the second acquisition position, and the actual interval distance L0=N*L1, and the total number of pulses corresponding to a single image is P, therefore, M=N*P (that is, the total number of pulses corresponding to N images is the interval pulse number). Substituting N=L0 / L1 into the formula, we can obtain M=L0*P / L1, where M represents the interval pulse number, L0 represents the actual interval distance, P represents the total number of pulses, and L1 represents the actual shooting area length.

[0173] For ease of understanding, the following example is provided, but it does not limit this application. As an example, assume that the actual interval distance between the first detection module and the second detection module is L0 = 3m (3000mm), and the actual shooting area length corresponding to a single image is set to L1 = 0.5m (500mm). Then N = 6 (3000 = 6 × 500), that is, the same area of ​​the electrode needs to pass through the shooting range of 6 images when moving from before cold pressing to after cold pressing. Assuming that the total number of pulses per image is P = 30000, then the number of interval pulses M = 30000 * 3000 / 500 = 180000 (that is, when the same area of ​​the electrode moves from the shooting position before cold pressing to the shooting position after cold pressing, the encoder will generate 180000 pulses). Assuming the image acquired by the second detection module after rolling is the image of region A after cold rolling, and the number of pulse intervals M=180000, then the image acquired by the first detection module before rolling before 180000 pulses is the image of region A before cold rolling, thus achieving image frame alignment of region A.

[0174] This embodiment calculates the interval pulse count of the same area of ​​the electrode captured by the first detection module and the second detection module based on the actual interval distance between the first detection module and the second detection module, the actual shooting area length corresponding to a single image, and the total number of pulses required to shoot a single image. This improves the accuracy of the interval pulse count and provides a precise timing basis for image frame alignment, ensuring that the images before and after cold pressing can accurately match the same area.

[0175] In some embodiments, the first detection module and the second detection module are line scan cameras; the control module is further configured to obtain the single-pixel accuracy of the first detection module and the second detection module and the number of pulses required to trigger the shooting of a single row of pixels, wherein the single-pixel accuracy represents the actual physical length corresponding to a single row of pixels; the control module is further configured to calculate the total number of pulses required to shoot a single image based on the number of pulses, the single-pixel accuracy and the actual shooting area length.

[0176] To adapt to the detection of continuously moving electrodes and achieve high-resolution, full-area (full width + full length) image acquisition, avoiding missed detections due to the limited field of view of traditional area scan cameras, in this embodiment, the first and second detection modules are line scan cameras. To achieve precise mapping between "electrode movement distance - pulse count - image acquisition," quantization parameters are provided for calculating the pulse interval for the same area captured by the cameras before and after cold pressing, ensuring accurate frame alignment. In this embodiment, the total number of pulses required to capture a single image is also calculated based on the single-pixel accuracy of the first and second detection modules, the number of pulses required to trigger the capture of a single row of pixels, and the actual length of the captured area.

[0177] In this context, a line scan camera can refer to a camera that scans line by line to form an image. It continuously acquires pixel information from a single line during the movement of an electrode, stitching the data together to create a complete image. This is suitable for full-area, high-resolution detection of continuously moving elongated objects (such as electrodes). Single-pixel accuracy refers to the actual physical length (in mm) corresponding to a single line of pixels in the line scan camera, representing the actual size covered by a single pixel on the electrode during imaging. The number of pulses required to trigger the capture of a single line of pixels refers to the number of pulses (denoted as X) generated by the encoder to trigger the line scan camera to capture a line of pixels. For example, X=3 means that every 3 pulses trigger the camera to capture a line of pixels.

[0178] In the specific implementation, both the first detection module (before cold pressing) and the second detection module (after cold pressing) use line scan cameras. The working method is as follows: when the electrode moves continuously along the belt direction, the line scan camera collects the single-line pixel information of the electrode line by line through the lens. The collection of each line of pixels is triggered synchronously by encoder pulses (one line is triggered every X pulses, where X can be preset, and this embodiment does not limit this). By continuously collecting multiple lines of pixels and stitching them together, a complete image covering the full width of the electrode (e.g., 800mm) and the actual shooting area length L1 (e.g., 500mm) is finally formed.

[0179] For ease of understanding, the following example is provided, but it does not limit this application. As an example, assume that the single pixel accuracy Y = 0.05mm, and the encoder generates 3 pulses (X = 3) to trigger the camera to capture one row of pixels (corresponding to a length of 0.05mm on the electrode). The calculation logic for the total number of pulses P required to capture a single image is as follows: 1. First, calculate the number of pixel rows contained in the single image in the conveyor direction: the actual shooting area length L1 divided by the single pixel accuracy Y, i.e., number of rows = L1 / Y; 2. Since each row of pixels requires X pulses to trigger the shooting, the total number of pulses P = number of rows * X = (L1 / Y) * X.

[0180] This embodiment calculates the total number of pulses required to capture a single image by using the single-pixel accuracy of the first and second detection modules, the number of pulses required to trigger the capture of a single row of pixels, and the actual length of the capture area. This provides quantitative parameters for calculating the pulse interval between the cameras capturing the same area before and after cold pressing, ensuring the accuracy of frame alignment.

[0181] In some embodiments, the single-pixel accuracy is less than a preset threshold, wherein the preset threshold is predetermined based on the measurement elongation accuracy.

[0182] To ensure that the width measurement error of the electrode sheet before and after cold pressing is within the allowable range, high-precision raw data is provided for the calculation of the first elongation rate, thereby meeting the accuracy requirements of the online monitoring of elongation rate (better than 0.05%), avoiding measurement deviations caused by insufficient pixel accuracy, and ensuring cell consistency. In this embodiment, the single pixel accuracy is less than a preset threshold, wherein the preset threshold is predetermined based on the measurement elongation rate accuracy.

[0183] The preset threshold refers to the maximum allowable value (unit: mm) of single-pixel accuracy set in advance to meet the accuracy requirements of electrode elongation measurement. Its value is determined based on the elongation measurement accuracy required by the process and is the critical value for judging whether the single-pixel accuracy meets the detection requirements. The measurement elongation accuracy refers to the accuracy of the system's measurement results of the electrode cold pressing elongation (expressed as a percentage). In this embodiment, the system's measurement elongation accuracy is better than 0.05%, which is the core basis for setting the preset threshold.

[0184] In practical implementation, hardware selection (such as the resolution and lens focal length of the line scan camera) and calibration ensure that the single-pixel accuracy (actual physical length) of the line scan camera is less than a preset threshold. The logic for determining the preset threshold is as follows: based on the required elongation measurement accuracy (e.g., "better than 0.05%)", the maximum allowable measurement error of the electrode width / film area width is calculated backwards, and this error value is then set as the preset threshold for single-pixel accuracy. For example, if the required elongation measurement accuracy is 0.05%, the measurement error of the electrode width must be less than "width before cold pressing × 0.05%", and the single-pixel accuracy must be less than this error value to ensure the accuracy of the elongation calculation.

[0185] For ease of understanding, the following example is provided, but it does not limit this application. As an example, assume that the process requires a measurement accuracy of 0.05% for the elongation rate, i.e., the calculation error of the elongation rate must be ≤0.05%. For a certain film area of ​​the electrode, the width D before cold pressing is 200mm. If the actual elongation rate is 1.0%, then the theoretical width after cold pressing is D' = 200 × (1 + 1.0%) = 202mm. To ensure an elongation rate measurement accuracy of 0.05%, the width measurement error must be ≤200 × 0.05% = 0.1mm (i.e., the measurement error of D or D' must be ≤0.1mm). At this time, the preset threshold is determined based on this 0.1mm (i.e., the single pixel accuracy must be ≤0.1mm). The actual single pixel accuracy of the system is 0.05mm, which is less than the preset threshold of 0.1mm, thus meeting the requirements.

[0186] This embodiment sets the single-pixel accuracy to be less than a preset threshold, wherein the preset threshold is determined in advance based on the measurement elongation accuracy. This ensures that the width measurement error before and after cold pressing of the electrode sheet is within the allowable range, providing high-precision raw data for the calculation of the first elongation, thereby meeting the accuracy requirements of the process for online monitoring of elongation. This also avoids measurement deviations caused by insufficient pixel accuracy and ensures cell consistency.

[0187] In some embodiments, the control module is further configured to acquire a first film width of multiple regions in the image before alignment and rolling, and acquire a second film width of the same region in the image after alignment and rolling; the control module is further configured to calculate the elongation of each region based on the first film width and the second film width; the control module is further configured to calculate a first elongation of the electrode in the direction perpendicular to the belt travel based on the elongation of each region.

[0188] In order to reflect the overall cold pressing elongation level of the electrode sheet, avoid misjudgment caused by partial local data, provide a global reference for the closed-loop control of the cold pressing equipment, ensure the consistency of the entire roll of electrode sheets, and reduce the risk of batch defects, in this embodiment, the elongation rate of each region is first calculated based on the first film width of multiple regions in the image before alignment and before rolling and the second film width of the same region in the image after alignment and after rolling. Then, the first elongation rate of the electrode sheet in the direction perpendicular to the belt conveyor is calculated based on the elongation rate of each region.

[0189] For ease of understanding, please refer to Figure 4 This explanation is provided, but does not limit the scope of this application. Figure 4 The diagram below illustrates the film widths of some embodiments of the present invention. As an example, the film widths D11, D12, D13, D21, D22, D23, D31, D32, and D33 of each region are taken at 0.25*L1, 0.5*L1, and 0.75*L1, respectively (e.g., ...). Figure 4 As shown in the figure); similarly, the dimensions D11', D12', D13', D21', D22', D23', D31', D32', and D33' (not shown in the figure) of each region after cold pressing are calculated based on the image after alignment and rolling. Assuming that in the image before alignment and rolling, the first film widths of the three sub-regions in the left area of ​​the electrode are: D11=200mm (left area 1), D21=200mm (left area 2), and D31=200mm (left area 3); and in the image after alignment and rolling, the second film widths of the same three sub-regions in the left area are: D11'=200.2mm, D21'=200.3mm, and D31'=200.1mm; (the corresponding film widths for the middle and right areas are obtained similarly; the left area is used as an example here). Based on the above film widths of the three sub-regions in the left area, the elongation δ of left area 1 can be calculated. D 11 = (200.2 - 200) / 200 × 100% = 0.1%; Left zone 2 elongation δ D 21 = (200.3 - 200) / 200 × 100% = 0.15%; Left zone 3 elongation δ D 31 = (200.1 - 200) / 200 × 100% = 0.05%; (The same calculation applies to the sub-regions of the central and right regions. For example, the elongation rates of the three sub-regions in the central region are 0.12%, 0.08%, and 0.11%, respectively; and in the right region, they are 0.09%, 0.13%, and 0.10%). The specific formula for calculating the first elongation rate of the electrode in the direction perpendicular to the travel direction based on the elongation rates of the above nine sub-regions is as follows:

[0190] δ D =(δ D 11+δ D 21+δ D 31+δ D 12+δ D 22+δD 32+δ D 13+δ D 23+δ D 33) / 9 = (0.1%+0.15%+0.05%+0.12%+0.08%+0.11%+0.09%+0.13%+0.10%) / 9 = 0.103%.

[0191] This embodiment first calculates the elongation of each region based on the first film width of multiple regions in the image before alignment and before rolling, and the second film width of the same region in the image after alignment and after rolling. Then, it calculates the first elongation of the electrode sheet in the direction perpendicular to the conveyor belt based on the elongation of each region. This can reflect the overall cold pressing elongation level of the electrode sheet, avoid misjudgment caused by the partiality of local data, provide a global reference for the closed-loop control of the cold pressing equipment, ensure the consistency of the entire roll of electrode sheets, and reduce the risk of batch defects.

[0192] In some embodiments, the first detection module and the second detection module are large field-of-view macro cameras, the field of view of the large field-of-view macro camera is greater than the width of the electrode, and the working distance of the large field-of-view macro camera is less than a preset distance.

[0193] To accommodate the compact space of the electrode production line, facilitate installation and maintenance, and ensure that image edges are not distorted, in this embodiment, the first detection module and the second detection module are large-field macro cameras. The field of view of the large-field macro camera is larger than the width of the electrode, and the working distance of the large-field macro camera is smaller than a preset distance.

[0194] A wide-field-of-view macro camera refers to a camera that combines a wide field of view with macro shooting capabilities. It can cover a large horizontal (TD) range while maintaining high resolution at close range, enabling precise capture of electrode details. The camera's field of view refers to the maximum physical range (in mm) that the camera lens can cover horizontally (TD), i.e., the maximum length of the image covered in the electrode's width direction. The electrode's width refers to the maximum width (in mm) of the electrode in the horizontal direction (TD direction, perpendicular to the transport direction). The working distance refers to the vertical distance (in mm) between the camera lens and the electrode surface, i.e., the actual distance between the camera and the electrode when mounted. The preset distance refers to the maximum allowable working distance (in mm) preset to ensure the camera's macro shooting effect and mounting compatibility.

[0195] In its implementation, the field of view (934mm) of the large-field macro camera is designed to be larger than the width of the electrode (800mm) to ensure that image edges are not distorted. The working distance (vertical distance between the lens and the electrode surface) of the large-field macro camera is controlled between 5-20mm, a range smaller than the preset distance (set to 20mm). Specifically, the camera position is fixed by a mechanical structure to ensure that the working distance does not exceed 20mm, but is not less than 5mm (to avoid contact between the lens and the electrode).

[0196] In this embodiment, the first and second detection modules are set as large-field macro cameras. The field of view of the large-field macro camera is larger than the width of the electrode sheet, and the working distance of the large-field macro camera is smaller than the preset distance. This allows it to be adapted to the compact space of the electrode sheet production line, making it easy to install and maintain, and ensuring that the image edges are not distorted.

[0197] In some embodiments, the elongation monitoring system further includes: a third detection module and a fourth detection module, wherein the third detection module is disposed on one side of the roll, and the fourth detection module is disposed on the other side of the roll; the third detection module is configured to, in response to the pulse, acquire the belt speed of the electrode before rolling and send the belt speed before rolling to the control module; the fourth detection module is configured to, in response to the pulse, acquire the belt speed of the electrode after rolling and send the belt speed after rolling to the control module; the control module is configured to calculate a second elongation of the electrode in the belt-carrying direction based on the belt speed before rolling and the belt speed after rolling.

[0198] To reduce the cost of detecting the second elongation of the electrode in the belt-carrying direction and avoid damaging the electrode, in this embodiment, a third detection module and a fourth detection module are respectively set on both sides of the roll. The third detection module and the fourth detection module detect the belt-carrying speed of the electrode before and after rolling, respectively, and calculate the second elongation of the electrode in the belt-carrying direction based on the belt-carrying speed before and after rolling.

[0199] The third detection module can be a Doppler laser velocimeter installed on the feed side of the cold press rolls. It uses non-contact laser interferometry to collect the real-time belt speed (V0) of the electrode sheet before it enters the rolls. The fourth detection module can be a Doppler laser velocimeter of the same model installed on the discharge side of the rolls, forming a "front-to-back" speed measurement system with the third module to collect the belt speed (V1) of the electrode sheet after rolling. Both modules must be strictly aligned with the electrode sheet centerline to ensure that the speed change is measured in the same film area.

[0200] For ease of understanding, please refer to Figure 3 and Figure 5 This explanation is provided, but does not limit the scope of this application. Figure 3 These are top views of the electrode rolling process in some embodiments of the present invention. Figure 5 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention. As an example, a roll 20 presses an electrode sheet, which moves along the belt feed direction. The movement of the electrode sheet triggers an encoder 40 to emit a pulse signal. This same pulse signal is split into four parts and sent to the first detection module 10, the second detection module 30, the third detection module 60, and the fourth detection module 70, respectively. This ensures that the first detection module 10 and the second detection module 30 take photos simultaneously, and that the third detection module 60 and the fourth detection module 70 measure speed simultaneously. The first detection module 10 and the second detection module 30 detect the first elongation δ of the electrode sheet in the direction perpendicular to the belt feed direction. D The specific steps have been explained above and will not be repeated here. Since the third detection module 60 and the fourth detection module 70 are respectively located on both sides of the roll 20, the speeds obtained when the third detection module 60 and the fourth detection module 70 measure speed synchronously are not the speeds of the same area of ​​the electrode sheet. To overcome the above defects, this embodiment uses frame alignment to ensure that the speeds measured by the two detection modules are the same area of ​​the electrode sheet before and after rolling. The specific steps of frame alignment are as follows: the control module 50 obtains the interval pulse number S of the speed measurement of the same area of ​​the electrode sheet by the third detection module 60 and the fourth detection module 70 (i.e., when the same area of ​​the electrode sheet moves from the image acquisition position corresponding to the third detection module 60 to the image acquisition position corresponding to the fourth detection module 70, the encoder 40 generates pulses), uses the speed measured by the fourth detection module as the belt speed V1 after rolling, and uses the speed measured by the third detection module before S pulses as the belt speed V0 before rolling. The interval pulse number S can be preset or calculated based on the actual parameters of the elongation monitoring system; this embodiment does not impose any restrictions on this. Figure 3 As shown, after obtaining the belt speed before and after rolling, the control module 50 calculates the second elongation δ of the electrode in the belt-carrying direction based on the belt speed before and after rolling. L The specific calculation formula is as follows:

[0201] δ L =(L'-L) / L)*100%=(V1*T-V0*T) / V0*T*100%=(V1-V0) / V0*100%

[0202] In the formula, δ L L represents the second elongation of the electrode sheet in the belt-carrying direction, L represents the length of the electrode sheet before rolling in the belt-carrying direction, L' represents the length of the electrode sheet after rolling in the belt-carrying direction, V0 represents the belt-carrying speed before rolling, and V1 represents the belt-carrying speed after rolling.

[0203] This embodiment sets a third detection module and a fourth detection module on both sides of the roll, respectively. The third detection module and the fourth detection module detect the belt speed before and after rolling of the electrode sheet, respectively. The second elongation of the electrode sheet in the belt direction is calculated based on the belt speed before and after rolling. Therefore, the second elongation of the electrode sheet in the belt direction can be calculated without marking the electrode sheet, thereby reducing the detection cost of the second elongation and avoiding damage to the electrode sheet.

[0204] In some embodiments, the third detection module is further configured to, in response to the pulse, simultaneously emit a first interference laser and a second interference laser toward the electrode, wherein the first interference laser and the second interference laser form a first Newton's ring on the electrode; the third detection module is further configured to, obtain the width of the first Newton's ring, calculate the pre-rolling speed of the electrode based on the width of the first Newton's ring, the angle between the first interference laser and the second interference laser, and the detection frequency of the third detection module, and send the pre-rolling speed to the control module.

[0205] To improve the measurement accuracy of the belt speed before rolling, in this embodiment, a first interference laser and a second interference laser are simultaneously emitted to the electrode, and the belt speed before rolling is calculated by a preset algorithm based on the first Newton's rings formed on the electrode by the first and second interference lasers.

[0206] The first and second interferometric lasers are two co-originating lasers emitted by the third detection module, serving as the core light source for Doppler velocimetry. The two lasers have a fixed angle (denoted as k, a pre-defined value from the hardware), the same wavelength (denoted as λ), and both are emitted perpendicular to the electrode's travel plane, working together to create an interference effect on the electrode surface. The first Newton's rings refer to the alternating bright and dark fringes generated by the optical path difference after the first and second interferometric lasers intersect on the electrode surface; these are invisible to the naked eye and must be detected by a photodiode built into the module. The fringe spacing (denoted as d) is directly related to the laser wavelength and the angle between the two lasers, and changes inversely with the electrode's travel speed (the faster the speed, the higher the fringe movement frequency, and the spacing indirectly reflects the speed characteristics).

[0207] In the specific implementation, the photodiode built into the third detection module captures the reflected signal of the first Newton's rings in real time, and the detection frequency f is calculated by back-calculating the signal period (t). The width d of Newton's rings is calculated based on hardware parameters. Different speeds will cause the width d of Newton's rings to change. Given λ (laser wavelength) and k (angle between the two laser beams), substitute them into the formula. We obtain d. Combined with the formula for the detection frequency f... Calculate the belt speed V0 before the electrode is rolled (where, Constant coefficients for module factory calibration, such as ).

[0208] This embodiment simultaneously emits a first interference laser and a second interference laser onto the electrode, and calculates the belt speed of the electrode before rolling by using a preset algorithm based on the first Newton's rings formed on the electrode by the first and second interference lasers. This improves the measurement accuracy of the belt speed before rolling, and further improves the accuracy of the second elongation rate.

[0209] In some embodiments, the fourth detection module is further configured to, in response to the pulse, simultaneously emit a third interference laser and a fourth interference laser toward the electrode, wherein the third interference laser and the fourth interference laser form a second Newton's ring on the electrode; the fourth detection module is further configured to, obtain the width of the second Newton's ring, calculate the post-rolling conveyor speed of the electrode based on the width of the second Newton's ring, the angle between the third interference laser and the fourth interference laser, and the detection frequency of the fourth detection module, and send the post-rolling conveyor speed to the control module.

[0210] To improve the measurement accuracy of the belt speed after rolling, in this embodiment, a third interference laser and a fourth interference laser are simultaneously emitted to the electrode, and the belt speed after rolling is calculated by a preset algorithm based on the second Newton's rings formed on the electrode by the third and fourth interference lasers.

[0211] The third and fourth interferometric lasers are two co-originating, same-wavelength lasers emitted by the fourth detection module, serving as the core light source for Doppler velocimetry. The two lasers have a fixed angle (denoted as k, consistent with the laser angle of the third module, a pre-defined known quantity in the hardware), a fixed wavelength (denoted as λ), and their emission direction is strictly perpendicular to the electrode's conveyor plane. Together, they act on the rolled electrode surface, creating an interference effect. The second Newton's rings refer to the alternating bright and dark fringes generated by the optical path difference after the third and fourth interferometric lasers intersect on the rolled electrode surface. These are invisible to the naked eye and must be captured by the module's built-in photodiode. The fringe spacing (denoted as d) is directly related to the laser wavelength (λ) and the angle (k) between the two lasers. In the specific implementation, the method for calculating the conveyor speed after rolling is similar to that before rolling, and will not be elaborated here.

[0212] This embodiment simultaneously emits a third interference laser and a fourth interference laser onto the electrode, and calculates the belt speed of the electrode after rolling by using a preset algorithm based on the second Newton's rings formed on the electrode by the third and fourth interference lasers. This improves the measurement accuracy of the belt speed after rolling, and further improves the accuracy of the second elongation rate.

[0213] In some embodiments, the third detection module and the fourth detection module are arranged perpendicular to the electrode, and the angles between the first interference laser and the electrode, the second interference laser and the electrode, the third interference laser and the electrode, and the fourth interference laser and the electrode are all 90 degrees.

[0214] To avoid other velocity components affecting the calculation of the second elongation rate, in this embodiment, the third and fourth detection modules are positioned perpendicular to the electrode, and the angle between the laser emitted by the sensor and the electrode is 90°. The angle between the interfering laser and the electrode can refer to the perpendicular angle between the propagation direction of each interfering laser and the electrode surface, not the angle (k) between the two laser beams. This angle needs to be ensured through hardware calibration (e.g., using a right-angle ruler for factory positioning and a laser level for on-site adjustment). Deviation will result in velocity component errors (Vmeasured = Vactual × cosθ, where θ is the deviation angle), directly leading to errors in the elongation rate calculation.

[0215] In this embodiment, the third and fourth detection modules are set perpendicular to the electrode, and the sensor emits a laser at a 90° angle with the electrode, thereby avoiding the influence of other velocity components on the calculation of the second elongation, and thus further improving the accuracy of the second elongation.

[0216] In some embodiments, the elongation monitoring system further includes: a first heat dissipation module corresponding to the third detection module and a second heat dissipation module corresponding to the fourth detection module; the first heat dissipation module is used to isolate the heat generated by the electrode rolling from the third detection module and / or to dissipate heat from the third detection module; the second heat dissipation module is used to isolate the heat generated by the electrode rolling from the fourth detection module and / or to dissipate heat from the fourth detection module.

[0217] In order to isolate the heat of the rolling mill and reduce the interference of the heat generated during the rolling process of the electrode sheet on the third and fourth detection modules, in this embodiment, the elongation monitoring system further includes: a first heat dissipation module corresponding to the third detection module and a second heat dissipation module corresponding to the fourth detection module. The heat dissipation modules dissipate heat from the detection modules by isolating heat and / or dissipating heat.

[0218] The heat generated during electrode rolling can refer to the heat generated by mechanical friction (between the roller and the electrode surface) and material deformation (compaction of electrode coating particles) during the cold press's extrusion of the electrode. Additionally, the operation of the roller drive motor also generates heat, leading to an increase in the ambient temperature around the detection module. This is the core heat source that the heat dissipation module needs to isolate. The first heat dissipation module can refer to a temperature control component (such as a heat shield, heat sink, or micro-fan) designed for the third detection module. It is integrated with or installed adjacent to the third detection module. Its core function is to isolate the heat generated during electrode rolling and to provide active / passive heat dissipation for the third detection module. Its structure must be adapted to the installation space of the third module (e.g., not obstructing the laser emission path or affecting the working distance from the electrode). The second heat dissipation module can refer to a temperature control component corresponding to the fourth detection module. It is integrated with the fourth detection module, and its function and structure are the same as the first heat dissipation module (ensuring symmetry and consistency). However, it can adapt to the higher temperature environment at the roller exit (the temperature after electrode pressing is higher than before pressing), and can be finely adjusted in terms of heat dissipation power or the thickness of the heat insulation material.

[0219] In this embodiment, the elongation monitoring system further includes: a first heat dissipation module corresponding to the third detection module and a second heat dissipation module corresponding to the fourth detection module. The heat dissipation module dissipates heat from the detection module by isolating heat and / or dissipating heat, thereby isolating the heat of the roll and reducing the interference of the heat generated during the electrode rolling process on the third and fourth detection modules, thereby improving the accuracy of speed measurement.

[0220] In some embodiments, the control module is further configured to calculate the pre-rolling film width of the electrode sheet in the direction perpendicular to the belt feeding direction based on the pre-rolling image, and calculate the post-rolling film width of the electrode sheet in the direction perpendicular to the belt feeding direction based on the post-rolling image; the control module is further configured to calculate the pre-rolling length of the electrode sheet in the belt feeding direction based on the pre-rolling belt feeding speed, and calculate the post-rolling length of the electrode sheet in the belt feeding direction based on the post-rolling belt feeding speed; the control module is further configured to calculate the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length.

[0221] In order to calculate the surface elongation of the electrode sheet and better reflect the consistency of the battery cell production, in this embodiment, the film width of the electrode sheet before and after rolling is calculated based on the images before and after rolling, respectively, in the direction perpendicular to the belt feeding direction. Then, the length of the electrode sheet before and after rolling is calculated based on the belt feeding speed before and after rolling. Finally, the surface elongation of the electrode sheet is calculated based on the film width and length before and after rolling.

[0222] For ease of understanding, please refer to Figure 3 This explanation is provided, but does not limit the scope of this application. Figure 3These are top views of the electrode before and after rolling according to some embodiments of the present invention. As an example, the pre-rolling film width D of the electrode in the direction perpendicular to the belt conveyor is calculated based on the pre-rolling image, the post-rolling film width D' of the electrode in the direction perpendicular to the belt conveyor is calculated based on the post-rolling image, the pre-rolling length L of the electrode in the belt conveyor direction is calculated based on the pre-rolling belt conveyor speed, and the post-rolling length L' of the electrode in the belt conveyor direction is calculated based on the post-rolling belt conveyor speed. Then, the formula for calculating the surface elongation δ is: δ=(D'*L' / D*L)-1, where δ is the surface elongation, D' is the post-rolling film width, L' is the post-rolling length, D is the pre-rolling film width, and L is the pre-rolling length.

[0223] In this embodiment, the film width of the electrode sheet before and after rolling is calculated based on the images before and after rolling, respectively, in the direction perpendicular to the belt feeding direction. Then, the length of the electrode sheet before and after rolling is calculated based on the belt feeding speed before and after rolling. Finally, the surface elongation of the electrode sheet is calculated based on the film width and length before and after rolling, thereby enabling the calculation of the surface elongation of the electrode sheet and better reflecting the consistency of battery cell production.

[0224] In some embodiments, the elongation monitoring system further includes: a roll host; the control module is further configured to send the elongation to the roll pressing host, wherein the elongation includes at least one of the first elongation, the second elongation, and the surface elongation; the roll host is configured to calculate the adjustment amount of the roll based on the elongation, and adjust the roll pressing parameters of the roll based on the adjustment amount.

[0225] In order to reduce the number of electrodes with poor elongation at the source, avoid batch events, and form a closed loop, the elongation monitoring system in this embodiment also includes: a rolling mill host. The rolling mill host calculates the adjustment amount of the rolling mill according to the elongation and adjusts the rolling pressure parameters of the rolling mill according to the adjustment amount, so as to optimize the rolling pressure parameters of the rolling mill in real time and bring the elongation of the electrode back to the qualified range.

[0226] The adjustment amount refers to the specific values ​​(such as pressure change, roll gap adjustment, angle adjustment, etc.) that the rolling mill needs to adjust the rolling parameters to bring the elongation back to the qualified range. It is calculated from the deviation of the elongation from the preset qualified range. Rolling parameters refer to the key operating parameters of the rolling mill during the cold pressing process, mainly including rolling pressure (the pressure applied to the electrode), roll gap (the gap between two rolling mills), and angle (the angle between two rolling mills), which directly affect the cold pressing elongation of the electrode.

[0227] For ease of understanding, please refer to Figure 6 This explanation is provided, but does not limit the scope of this application. Figure 6 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 6In the process, after calculating the overall elongation and elongation of each region of the electrode sheet, the control module 50 transmits this data to the control interface of the rolling mill 80 in real time. The transmission method is electrical signal (such as analog or digital signal), ensuring that the data delay is less than 100ms, so that the rolling mill 80 can obtain the current elongation status in a timely manner. After receiving the elongation data, the rolling mill host 80 calculates the adjustment amount through its built-in algorithm: if the elongation is higher than the upper limit (e.g., 0.18% > 0.15%), it indicates that the rolling pressure is too high (the higher the pressure, the more obvious the electrode elongation), and the pressure needs to be reduced. The adjustment amount is "current pressure - pressure value corresponding to the deviation" (e.g., a deviation of 0.03% corresponds to a pressure reduction of 5kN); if the elongation is lower than the lower limit (e.g., 0.03% < 0.05%), it indicates that the pressure is too low, and the pressure needs to be increased. The adjustment amount is "current pressure + pressure value corresponding to the deviation". The main adjustment parameter is the rolling pressure (achieved through the hydraulic system). If necessary, the roll gap (distance between two rolls) and angle (angle between two rolls) are adjusted as auxiliary parameters. The adjustment process is carried out in steps (e.g., adjusting 2kN each time to avoid sudden parameter changes).

[0228] The elongation monitoring system in this embodiment also includes a roll host. The roll host calculates the adjustment amount of the roll based on the elongation and adjusts the roll pressing parameters of the roll based on the adjustment amount. This enables real-time optimization of the roll pressing parameters, allowing the electrode elongation to return to the qualified range. This reduces the number of electrodes with poor elongation from the source, avoids batch events, and forms a closed loop.

[0229] In some embodiments, the rolling mill host is further configured to calculate the difference between the elongation rate and a preset elongation rate threshold, and to calculate the adjustment amount of the rolling mill based on the elongation rate difference; the rolling mill host is further configured to adjust the rolling pressure parameters of the rolling mill according to the adjustment amount and a preset adjustment step.

[0230] To improve the accuracy of the adjustment amount, this embodiment calculates the adjustment amount of the roll based on the difference between the elongation rate and the preset elongation rate threshold, and to avoid over-adjustment and reduce elongation rate fluctuations. In this embodiment, the roll pressure parameters of the roll are adjusted according to the adjustment amount and a preset adjustment step.

[0231] The preset elongation threshold can include an upper and lower limit for elongation, which are pre-existing acceptable range standards in the rolling mill's process parameter library. These must be set according to the electrode type (cathode / anode), specifications, and process objectives. The elongation difference refers to the deviation between the actual elongation calculated by the rolling mill and the preset threshold. It falls into two scenarios: If the actual elongation > the upper threshold: difference = actual elongation - upper threshold (e.g., actual 1.8%, upper limit 1.5%, difference 0.3%); if the actual elongation < the lower threshold: difference = lower threshold - actual elongation (e.g., actual 0.3%, lower limit 0.5%, difference 0.2%). The magnitude of the difference directly determines the calculation of the adjustment amount and is the core basis for triggering roll pressure parameter adjustments. The preset adjustment step refers to the smallest unit of adjustment per cycle, used to avoid excessive adjustment at once that could cause the elongation to exceed the limit. The step value can be set according to the electrode material characteristics to ensure a smooth and controllable adjustment process.

[0232] This embodiment calculates the adjustment amount of the roll based on the difference between the elongation rate and the preset elongation rate threshold, thereby improving the accuracy of the adjustment amount. Furthermore, the roll pressure parameters of the roll are adjusted according to the preset adjustment steps based on the adjustment amount, thereby avoiding over-adjustment and reducing elongation rate fluctuations.

[0233] In some embodiments, the rolls include: a first roll and a second roll, the first roll and the second roll being disposed correspondingly; the roll host is further configured to acquire the current roll pressure angle of the first roll and / or the second roll; the roll host is further configured to calculate the roll pressure angle adjustment amount of the second roll and / or the first roll based on the elongation and the current roll pressure angle.

[0234] In order to achieve precise local pressure control in the width direction and solve the problem of unevenness caused by overall pressure adjustment (such as reducing the overall pressure to make the right area qualified but the left area lower), and improve the consistency of the elongation of the entire electrode sheet, in this embodiment, the rolls include: a first roll and a second roll. The roll angle of the second roll and / or the first roll can also be adjusted according to the elongation and the current roll angle of the first roll and / or the second roll.

[0235] The first roll can refer to the cylindrical roll located on one side of the electrode sheet (as shown above) in the rolling mill, which works in conjunction with the second roll to apply pressure to the electrode sheet and is one of the core components in the cold pressing process. The second roll can refer to the cylindrical roll located on the other side of the electrode sheet (as shown below) in the rolling mill, corresponding to the first roll, together forming the working area for cold pressing the electrode sheet. Cold pressing of the electrode sheet is achieved through relative rotation and pressure application. The corresponding arrangement can mean that the centerlines of the first roll and the second roll are parallel and the distance between them is adjustable, and the roll surfaces face each other to form a roll gap (the gap between the two rolls) for the electrode sheet to pass through, ensuring that the electrode sheet can be uniformly pressed. The current roll pressure angle can refer to the tilt angle of the first roll and / or the second roll relative to a reference position (such as horizontal or vertical direction), reflecting the pressure distribution state of the roll in the axial direction (TD direction) (changes in angle will cause changes in the uniformity of the roll gap in the width direction). The roll angle adjustment amount refers to the angle value (unit: degree or minute) that needs to be adjusted to bring the electrode elongation back to the qualified range. It is calculated by combining the elongation deviation and the current angle.

[0236] For ease of understanding, please refer to Figure 7 This explanation is provided, but does not limit the scope of this application. Figure 7 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 7 In this rolling mill, the core components are a pair of first rolls (upper roll) 21 and second rolls (lower roll) 22, with their centerlines parallel and correspondingly distributed in the vertical direction (the electrode passes through the roll gap between the two rolls). The rolling mill host 80 collects the current roll pressure angle of the first roll 21 and / or the second roll 22 in real time through angle sensors (such as encoders or inclinometers) installed at the ends of the roll shafts. This angle reflects whether the rolls are in a horizontal reference position (0°): if the angle is 0°, the two rolls are completely parallel, and the pressure is uniform in the width direction; if the angle deviates from 0° (such as the right end of the first roll 21 tilting upward by 0.5°), the roll gap will be narrower on the left and wider on the right in the width direction, resulting in greater pressure on the left side of the electrode than on the right side, and a higher elongation in the left side than on the right side. The current angle data is transmitted to the control unit of the rolling mill host in real time as a basis for adjustment.

[0237] The control unit of the rolling mill 80 has a built-in algorithm that calculates the adjustment amount based on the elongation deviation of each region of the electrode sheet (the difference from the target value) and the current roll pressure angle. If the elongation of a certain region is higher than the target value (e.g., 0.18% in the right region > 0.15% of the target), and the current angle shows that the roll in that region is tilted, resulting in excessive pressure (e.g., the second roll 22 tilts to the right, making the roll gap in the right region narrow), then the angle needs to be adjusted in the opposite direction (e.g., the right end of the second roll 22 is adjusted upward by 0.1°) to increase the roll gap in that region and reduce the pressure. If the elongation of a certain region is lower than the target value (e.g., 0.08% in the left region < 0.12% of the target), and the current angle shows insufficient pressure, then the angle needs to be adjusted in the positive direction (e.g., the left end of the first roll 21 is adjusted downward by 0.05°) to reduce the roll gap and increase the pressure. The adjustment amount needs to be accurately calculated based on the elongation deviation and the influence coefficient of the angle on the pressure (e.g., 0.1° angle corresponds to a 0.03% change in elongation) to ensure that the elongation returns to the target range after adjustment.

[0238] The rollers in this embodiment include a first roller and a second roller. The rolling angle of the second roller and / or the first roller can be adjusted according to the elongation and the current rolling angle of the first roller and / or the second roller, thereby achieving precise local pressure control in the width direction. This avoids the problem of uneven regional elongation caused by overall pressure adjustment and improves the consistency of the elongation of the entire electrode.

[0239] In some embodiments, the elongation monitoring system further includes: a display module; the control module is further configured to send the elongation to the display module; the display module is configured to receive the elongation sent by the control module and display the elongation.

[0240] To enable operators to monitor the cold pressing and stretching status of the electrode in real time and promptly identify areas exceeding tolerance, the stretching rate monitoring system in this embodiment further includes a display module, which receives the stretching rate sent by the control module and displays the stretching rate.

[0241] The display module can refer to an industrial-grade display connected to the control module (such as an industrial computer). It is a visual output terminal for elongation data, and needs to be adapted to the production line workshop environment (such as dust resistance and high temperature resistance). It supports multi-dimensional data display (By meter / By film roll / By day) and has an abnormal alarm marking function. Its core function is to allow operators to intuitively obtain elongation data and promptly detect and handle abnormalities.

[0242] For ease of understanding, please refer to Figure 8 and Figure 9 This explanation is provided, but does not limit the scope of this application. Figure 8 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention. Figure 9 This is a schematic diagram of the display module interface according to some embodiments of the present invention. As an example, such as... Figure 8As shown, the control module 50 binds the elongation rate to the "film zone positioning information": (1) encoder pulse number (e.g., pulse number 20000-20049, corresponding to the 20-meter film zone of the electrode); (2) film roll number (identifying the current production batch); (3) production time (accurate to the second), ensuring that each set of elongation rate data can be traced back to the specific film zone and batch. The ModBus protocol is used to transmit data. This protocol has strong anti-interference capabilities and can cope with the electromagnetic environment of the production line (e.g., the electromagnetic field of the roller motor), ensuring that the data packet loss rate is ≤0.001%, avoiding display interruption due to data loss. As an example, such as Figure 9 As shown, the display module can display and adjust the intuitive display of By meter / membrane roll / day, and promptly identify discrete abnormal materials and their membrane roll numbers.

[0243] The elongation monitoring system in this embodiment also includes a display module, which receives the elongation rate sent by the control module and displays the elongation rate, thereby enabling operators to monitor the cold pressing elongation status of the electrode in real time and promptly detect out-of-tolerance areas.

[0244] In some embodiments, the elongation monitoring system further includes: an alarm module; the control module is further configured to send an alarm command to the alarm module when the elongation does not meet the preset specifications; the alarm module is configured to stop rolling according to the alarm command and generate a prompt message corresponding to the alarm command.

[0245] To achieve automatic identification and command triggering of anomalies, avoid the lag and misjudgment of manual judgment, ensure the timeliness and accuracy of alarm actions, and buy time for subsequent shutdown and processing, thereby reducing the risk of batch defects from a mechanism perspective, in this embodiment, the elongation monitoring system also includes an alarm module. The alarm module stops the rolling process according to the alarm command and generates the corresponding prompt information.

[0246] An alarm module can refer to a component (such as an audible and visual alarm or a shutdown control unit) that receives alarm commands from the control module, executes shutdown operations, and generates prompt information. It serves as an emergency response device when the elongation rate is abnormal. A preset specification refers to a pre-defined acceptable elongation rate range (e.g., 0.05%-0.15%), determined by process requirements, and is the basis for the control module to determine whether the elongation rate is abnormal. An alarm command is an electrical signal sent by the control module to the alarm module when the elongation rate does not meet the preset specification. This signal includes information such as the abnormal area and the out-of-tolerance value, triggering the alarm module's action. Prompt information refers to text, audible, and visual prompts generated by the alarm module based on the alarm command (e.g., "Right zone 2 elongation rate exceeds upper limit" or "Please check roll pressure"), used to inform operators of the cause of the abnormality and the appropriate course of action.

[0247] For ease of understanding, please refer to Figure 10 This explanation is provided, but does not limit the scope of this application. Figure 10 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 10 In the process, the control module 50 compares the calculated elongation rate of each region and the overall elongation rate with the preset specifications (e.g., 0.05%-0.15%) in real time. If the elongation rate of any region is ≥0.05% and ≤0.15%, it is determined to "meet the preset specifications," and the elongation rate is sent to the rolling host so that the rolling host can calculate the adjustment amount of the roll based on the elongation rate and adjust the rolling parameters of the roll according to the adjustment amount. If the elongation rate of any region is <0.05% (below the lower limit) or >0.15% (above the upper limit), it is determined to "not meet the preset specifications." At this time, the control module immediately generates an alarm command, including information such as the out-of-tolerance region (e.g., "Right Zone 2"), the out-of-tolerance value (e.g., "0.18%)", and the out-of-tolerance type ("above the upper limit"), and sends it to the alarm module 100 through wired communication (e.g., signal line). After receiving the alarm command from the control module, the alarm module 100 performs two core operations:

[0248] 1. Stop rolling: Cut off the drive power of the rolls through the stop control unit, so that the first and second rolls stop rotating, the movement of the electrode sheets is interrupted, and the out-of-tolerance area is prevented from continuing to be cold-pressed and flowing into the next process;

[0249] 2. Generate prompt information: Based on the out-of-tolerance area and value in the instruction, control the action of the sound and light alarm device (such as flashing warning light and buzzer sounding), and at the same time pop up a text prompt on the display module (such as "Right zone 2 elongation exceeds the upper limit by 0.03%, the machine has been stopped, please check the pressure of the right zone of the roll") to guide the operator to troubleshoot the problem (such as roll angle deviation, abnormal pressure).

[0250] The elongation monitoring system in this embodiment also includes an alarm module. The alarm module stops the rolling process according to the alarm command and generates a prompt message corresponding to the alarm command. This enables automatic identification of abnormalities and command triggering, avoiding the lag and misjudgment of manual judgment, ensuring the timeliness and accuracy of alarm actions, and buying time for subsequent shutdown and processing, thereby reducing the risk of batch defects from a mechanism perspective.

[0251] In some embodiments, the elongation monitoring system further includes: an encoding roller corresponding to the encoder; the encoding roller is used to rotate accordingly when the electrode moves, and the rotation of the encoding roller drives the encoder to trigger pulses.

[0252] To ensure that the pulse signal accurately reflects the actual moving distance of the electrode and provides a precise timing reference for subsequent synchronous image acquisition and image frame alignment by the camera, in this embodiment, the elongation monitoring system further includes: an encoder roller corresponding to the encoder, which rotates when the electrode moves, and the rotation of the encoder roller drives the encoder to trigger pulses.

[0253] The encoder roller can refer to a cylindrical roller that is directly connected to the encoder. Its surface is in close contact with the pole pieces. When the pole pieces move, the encoder is driven to rotate, thereby driving the encoder to work. It is the mechanical carrier for the encoder to obtain information about the movement of the pole pieces.

[0254] For ease of understanding, please refer to Figure 11 This explanation is provided, but does not limit the scope of this application. Figure 11 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 11 In the elongation monitoring system, the encoder 40 does not operate independently but is mechanically connected to the encoder roller 41 (e.g., the encoder shaft and encoder roller shaft are fixed by a coupling). The encoder roller 41 is a smooth metal roller (ensuring good contact with the electrode) and is installed on the electrode's conveyor path (usually the drive roller that moves the electrode). When the electrode passes over the surface of the encoder roller 41, friction causes the encoder roller 41 to rotate, and the rotation of the encoder roller 41 directly drives the encoder 40, forming a linkage mechanism of "electrode movement → encoder roller rotation → encoder operation". When the electrode moves along the conveyor direction, the friction between its surface and the surface of the encoder roller 41 causes the encoder roller 41 to rotate around its axis, and the rotation speed of the encoder roller 41 is proportional to the speed of the electrode movement (the faster the electrode moves, the faster the encoder roller 41 rotates). When the encoder roller 41 rotates, the photosensitive element or mechanical structure inside the encoder 40 connected to it rotates together. A pulse signal is generated for every fixed angle of rotation. That is, the relationship between "pole moving distance → encoder roller rotation angle → encoder pulse count" is strictly linear.

[0255] The elongation monitoring system in this embodiment also includes: an encoder roller corresponding to the encoder, which rotates when the electrode moves. The rotation of the encoder roller drives the encoder to trigger pulses, thereby ensuring that the pulse signal can truly reflect the actual moving distance of the electrode, providing an accurate timing reference for subsequent synchronous image acquisition by the camera and image frame alignment.

[0256] In some embodiments, the encoder roller is an active roller; the active roller is used to drive the electrode sheet to move by actively rotating, and to drive the encoder to trigger pulses.

[0257] In order to reduce the relative slippage between the electrode and the roller body, and to ensure that the rotation angle of the encoder roller corresponds strictly to the actual movement distance of the electrode, so as to guarantee the accuracy of the encoder pulse signal and avoid the deviation between the number of pulses and the actual movement distance caused by slippage, in this embodiment, the encoder roller is an active roller; the active roller drives the electrode to move by actively rotating, and drives the encoder to trigger pulses.

[0258] An active roller refers to a roller that is actively driven to rotate by a drive device (such as a motor), rather than being passively driven to rotate by the electrode sheet. It drives the electrode sheet to move along the belt conveyor direction through its own rotation, serving as one of the power sources for electrode sheet movement in the production line. Active rotation can refer to the active rotational motion of the active roller driven by a drive device (such as a servo motor). Its speed can be precisely controlled by a control system to match the required movement speed for electrode sheet production. Driving electrode sheet movement can refer to the active roller converting its own active rotation into linear motion of the electrode sheet through friction between its surface and the electrode sheet, allowing the electrode sheet to continuously and stably pass through processes such as the pre-cold pressing inspection area, the rolling mill, and the post-cold pressing inspection area along the belt conveyor direction. Driving encoder trigger pulses can refer to the active roller rotating, which drives the encoder to rotate synchronously through a mechanical connection (such as a coupling). The encoder generates an electrical pulse signal every fixed angle of rotation, and the number of pulses is proportional to the rotation angle of the active roller (i.e., the distance the electrode sheet moves).

[0259] In its implementation, the encoding roller is designed as an active roller, meaning it is directly connected to a drive device (such as a servo motor) and rotates actively via motor drive, rather than passively relying on the movement of the electrode. This design allows the encoding roller to perform two functions simultaneously: first, as the driving source for the movement of the electrode (driving the electrode through active rotation); and second, as the mechanical carrier of the encoder (triggering the encoder to generate pulses through its own rotation). This effectively reduces errors caused by slippage between the electrode and the imaging roller, ensuring synchronization between electrode movement and pulse signals through the characteristics of the active roller.

[0260] In this embodiment, the encoder roller is an active roller. The active roller drives the pole piece to move by actively rotating, and drives the encoder to trigger pulses. This reduces the relative slippage between the pole piece and the roller body, and makes the rotation angle of the encoder roller strictly correspond to the actual movement distance of the pole piece. This ensures the accuracy of the encoder pulse signal and avoids the deviation between the number of pulses and the actual movement distance caused by slippage.

[0261] In some embodiments, such as Figure 12 As shown, a method for monitoring elongation is proposed, including:

[0262] Step S10: Roll forming the electrode sheet, which moves along the belt conveyor direction.

[0263] Step S20: Trigger a pulse when the electrode moves.

[0264] Step S30: In response to the multiple pulses, acquire an image of the electrode sheet before rolling.

[0265] Step S40: In response to the multiple pulses, acquire an image of the electrode after rolling.

[0266] Step S50: Perform image frame alignment on the image before rolling and the image after rolling, and calculate the first elongation rate of the electrode in the direction perpendicular to the belt conveyor based on the aligned image before rolling and the aligned image after rolling. The image frame alignment is used to ensure that the image acquisition area of ​​the aligned image before rolling and the image acquisition area of ​​the aligned image after rolling correspond to the same area of ​​the electrode.

[0267] To reduce the cost of elongation monitoring and avoid damage to the electrode, this embodiment uses pulses triggered by the encoder when the electrode moves to ensure that the two detection modules detect synchronously, and uses image frame alignment to ensure that the two detection modules capture the same area of ​​the electrode before and after rolling.

[0268] In this embodiment, the elongation monitoring method can be applied to an elongation monitoring system, which refers to a system for online real-time monitoring of the elongation of lithium battery electrodes after cold pressing. Through non-destructive testing, full-area coverage, synchronous alignment, and closed-loop control, it achieves accurate measurement and control of the electrode elongation. The machine direction (MD) refers to the direction of electrode movement on the production line, perpendicular to the horizontal direction (TD). The first detection module refers to a detection device located on one side of the rolls, specifically a large-field macro camera before cold pressing, used to acquire images of the electrode before cold pressing. The rolls refer to cold pressing rolls, used to cold press the electrodes; they are the core equipment for electrode deformation (elongation), and their pressure can be adjusted to correct the elongation. The second detection module refers to a detection device located on the other side of the rolls, specifically a macro camera after cold pressing, operating in the same way as the first detection module, used to acquire images of the electrode after cold pressing. The encoder generates pulse signals as the electrode moves, providing synchronous trigger signals to the first and second detection modules to ensure that the time and position of their acquired images are matched. The control module is responsible for receiving image data from the first and second detection modules, performing image frame alignment, and calculating the elongation rate. The first elongation rate can refer to the elongation rate of the electrode in the direction perpendicular to the belt travel direction, i.e., the elongation rate of the electrode in the TD direction.

[0269] For ease of understanding, please refer to Figure 1 , Figure 2 as well as Figure 3 This explanation is provided, but does not limit the scope of this application. Figure 1 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention. Figure 2 These are front and rear side views of the electrode rolling process according to some embodiments of the present invention. Figure 3 These are top views of the electrode roll forming process before and after some embodiments of the present invention. As an example, such as... Figure 1 and Figure 2As shown, the roller 20 presses the electrode sheet, causing it to extend and move along the belt conveyor direction. This movement triggers the encoder 40 to emit a pulse signal. This same pulse signal is split into two and sent to the first detection module 10 and the second detection module 30 respectively, ensuring that the first detection module 10 and the second detection module 30 take pictures synchronously. Since the first detection module 10 and the second detection module 30 are located on opposite sides of the roller 20, the images obtained when they take pictures synchronously are not of the same area of ​​the electrode sheet. To overcome the aforementioned shortcomings, this embodiment uses frame alignment to ensure that the two detection modules capture the same area of ​​the electrode sheet before and after rolling. The specific steps of frame alignment are as follows: the control module 50 obtains the interval pulse number M between the first detection module 10 and the second detection module 30 capturing the same area of ​​the electrode sheet (i.e., the encoder 40 generates pulses when the same area of ​​the electrode sheet moves from the image acquisition position corresponding to the first detection module 10 to the image acquisition position corresponding to the second detection module 30). The currently captured image after rolling is used as the aligned image after rolling, and the image before rolling captured M pulses prior is used as the image before rolling corresponding to the aligned image after rolling. The interval pulse number M can be preset or calculated based on the actual parameters of the elongation monitoring system; this embodiment does not impose any restrictions on this. Figure 3 As shown, after obtaining the alignment before rolling image and the alignment after rolling image, the control module 50 calculates the pre-rolling film width D of the electrode in the direction perpendicular to the belt feed direction using image recognition technology based on the pre-rolling image, and calculates the post-rolling film width D' of the electrode in the direction perpendicular to the belt feed direction based on the post-rolling image. It then calculates the first elongation δ of the electrode in the direction perpendicular to the belt feed direction based on the pre-rolling and post-rolling film widths. D The specific calculation formula is δ D =(D'-D) / D*100%, where δ D D represents the first elongation of the electrode in the direction perpendicular to the belt travel, D represents the film width before rolling, and D' represents the film width after rolling.

[0270] This embodiment ensures synchronous detection by triggering pulses when the electrode moves, and ensures that the same area of ​​the electrode is captured before and after rolling by image frame alignment. Therefore, the first elongation of the electrode in the direction perpendicular to the belt can be calculated without marking the electrode, thereby reducing the cost of monitoring the first elongation and avoiding damage to the electrode.

[0271] In some embodiments, such as Figure 13 As shown, step S50 includes:

[0272] Step S501: Obtain the actual interval distance between the acquisition position of the image before rolling and the acquisition position of the image after rolling, and obtain the actual shooting area length corresponding to a single image, wherein an integer multiple of the actual shooting area length is the actual interval distance.

[0273] Step S502: Obtain the total number of pulses required to capture a single image.

[0274] Step S503: Calculate the interval pulse count between the first detection module corresponding to the image before rolling and the second detection module corresponding to the image after rolling for capturing the same area of ​​the electrode sheet based on the actual interval distance, the actual shooting area length, and the total number of pulses.

[0275] Step S504: Align the image frames of the image before and after rolling according to the number of interval pulses.

[0276] Step S505: Calculate the first elongation of the electrode sheet in the direction perpendicular to the belt travel based on the image before and after alignment and rolling.

[0277] To improve the accuracy of the interval pulse count and provide precise timing data for image frame alignment, ensuring that images before and after cold pressing accurately match the same area, this embodiment calculates the interval pulse count for the same area of ​​the electrode captured by the first and second detection modules based on the actual interval distance between the first and second detection modules, the actual shooting area length corresponding to a single image, and the total number of pulses required to capture a single image.

[0278] The actual interval distance can refer to the actual length of the electrode in the belt-carrying direction between the first acquisition position of the first detection module and the second acquisition position of the second detection module (i.e., the true distance between the electrodes between the two acquisition points, denoted as L0). The actual acquisition area length corresponding to a single image can refer to the actual length of the electrode covered by a single image in the belt-carrying direction (i.e., the physical length of the electrode in the belt-carrying direction contained in an image, denoted as L1). The total number of pulses can refer to the total number of pulses generated by the encoder to trigger the acquisition of a single image (i.e., the number of pulses output by the encoder during the acquisition of an image, denoted as P). The interval pulse count can refer to the difference in the number of pulses generated by the encoder when the first detection module acquires an image of a certain area and when the second detection module acquires an image of the same area (i.e., the number of pulses generated by the encoder when the same area of ​​the electrode moves from the first acquisition position corresponding to the first detection module to the second acquisition position corresponding to the second detection module, denoted as M).

[0279] In the specific implementation, the actual distance between the camera before and after cold pressing in the electrode transport direction is determined by physical measurement (such as laser ranging), i.e., the actual interval distance L0. To provide basic geometric parameters for subsequent image frame alignment and ensure that images of the same area of ​​the electrode before and after cold pressing can be associated through an integer multiple of the number of images, avoiding regional misalignment due to distance mismatch, in this embodiment, the actual length L1 of the electrode covered by a single image in the transport direction is set, and L1 is adjusted so that L0 is an integer multiple of L1 (i.e., L0 = N * L1, where N is a positive integer, ensuring that when the same area of ​​the electrode moves from the first acquisition position to the second acquisition position, it is exactly completely covered by N images). The total number of pulses P required to capture a single image is obtained. The total number of pulses P can be preset or calculated based on the actual parameters of the elongation monitoring system; this embodiment does not impose any restrictions on this. Since the interval pulse number M is the total number of pulses generated by the encoder when the same area of ​​the electrode moves from the first acquisition position to the second acquisition position, and the actual interval distance L0=N*L1, and the total number of pulses corresponding to a single image is P, therefore, M=N*P (that is, the total number of pulses corresponding to N images is the interval pulse number). Substituting N=L0 / L1 into the formula, we can obtain M=L0*P / L1, where M represents the interval pulse number, L0 represents the actual interval distance, P represents the total number of pulses, and L1 represents the actual shooting area length.

[0280] For ease of understanding, the following example is provided, but it does not limit this application. As an example, assume that the actual interval distance between the first detection module and the second detection module is L0 = 3m (3000mm), and the actual shooting area length corresponding to a single image is set to L1 = 0.5m (500mm). Then N = 6 (3000 = 6 × 500), that is, the same area of ​​the electrode needs to pass through the shooting range of 6 images when moving from before cold pressing to after cold pressing. Assuming that the total number of pulses per image is P = 30000, then the number of interval pulses M = 30000 * 3000 / 500 = 180000 (that is, when the same area of ​​the electrode moves from the shooting position before cold pressing to the shooting position after cold pressing, the encoder will generate 180000 pulses). Assuming the image acquired by the second detection module after rolling is the image of region A after cold rolling, and the number of pulse intervals M=180000, then the image acquired by the first detection module before rolling before 180000 pulses is the image of region A before cold rolling, thus achieving image frame alignment of region A.

[0281] This embodiment calculates the number of interval pulses between the acquisition positions of the images before and after rolling based on the actual distance between the acquisition positions of the images before and after rolling, the actual shooting area length corresponding to a single image, and the total number of pulses required to capture a single image. This improves the accuracy of the interval pulse count and provides a precise timing basis for image frame alignment, ensuring that the images before and after cold pressing can accurately match the same area.

[0282] In some embodiments, such as Figure 14 As shown, step S502 includes:

[0283] Step S5021: Obtain the single-pixel precision of the image before and after rolling and the number of pulses required to trigger the shooting of a single row of pixels, wherein the single-pixel precision represents the actual physical length corresponding to a single row of pixels.

[0284] Step S5022: Calculate the total number of pulses required to capture a single image based on the pulse count, the single pixel precision, and the actual shooting area length.

[0285] To adapt to the detection of continuously moving electrodes and achieve high-resolution, full-area (full width + full length) image acquisition, avoiding missed detections due to the limited field of view of traditional area scan cameras, in this embodiment, the first and second detection modules are line scan cameras. To achieve precise mapping between "electrode movement distance - pulse count - image acquisition," quantization parameters are provided for calculating the pulse interval for the same area captured by the cameras before and after cold pressing, ensuring accurate frame alignment. In this embodiment, the total number of pulses required to capture a single image is also calculated based on the single-pixel accuracy of the first and second detection modules, the number of pulses required to trigger the capture of a single row of pixels, and the actual length of the captured area.

[0286] In this context, a line scan camera can refer to a camera that scans line by line to form an image. It continuously acquires pixel information from a single line during the movement of an electrode, stitching the data together to create a complete image. This is suitable for full-area, high-resolution detection of continuously moving elongated objects (such as electrodes). Single-pixel accuracy refers to the actual physical length (in mm) corresponding to a single line of pixels in the line scan camera, representing the actual size covered by a single pixel on the electrode during imaging. The number of pulses required to trigger the capture of a single line of pixels refers to the number of pulses (denoted as X) generated by the encoder to trigger the line scan camera to capture a line of pixels. For example, X=3 means that every 3 pulses trigger the camera to capture a line of pixels.

[0287] In the specific implementation, both the first detection module (before cold pressing) and the second detection module (after cold pressing) use line scan cameras. The working method is as follows: when the electrode moves continuously along the belt direction, the line scan camera collects the single-line pixel information of the electrode line by line through the lens. The collection of each line of pixels is triggered synchronously by encoder pulses (one line is triggered every X pulses, where X can be preset, and this embodiment does not limit this). By continuously collecting multiple lines of pixels and stitching them together, a complete image covering the full width of the electrode (e.g., 800mm) and the actual shooting area length L1 (e.g., 500mm) is finally formed.

[0288] For ease of understanding, the following example is provided, but it does not limit this application. As an example, assume that the single pixel accuracy Y = 0.05mm, and the encoder generates 3 pulses (X = 3) to trigger the camera to capture one row of pixels (corresponding to a length of 0.05mm on the electrode). The calculation logic for the total number of pulses P required to capture a single image is as follows: 1. First, calculate the number of pixel rows contained in the single image in the conveyor direction: the actual shooting area length L1 divided by the single pixel accuracy Y, i.e., number of rows = L1 / Y; 2. Since each row of pixels requires X pulses to trigger the shooting, the total number of pulses P = number of rows * X = (L1 / Y) * X.

[0289] This embodiment calculates the total number of pulses required to capture a single image by using the single-pixel accuracy of the images before and after rolling, the number of pulses required to trigger the capture of a single row of pixels, and the actual length of the shooting area. This provides quantitative parameters for calculating the pulse interval for the cameras capturing the same area before and after cold pressing, ensuring the accuracy of frame alignment.

[0290] In some embodiments, such as Figure 15 As shown, step S505 includes:

[0291] Step S5051: Obtain the first film width of multiple regions in the image before alignment and roll pressing, and obtain the second film width of the same region in the image after alignment and roll pressing.

[0292] Step S5052: Calculate the elongation of each region based on the first film width and the second film width.

[0293] Step S5053: Calculate the first elongation of the electrode in the direction perpendicular to the belt travel based on the elongation of each region.

[0294] In order to reflect the overall cold pressing elongation level of the electrode sheet, avoid misjudgment caused by partial local data, provide a global reference for the closed-loop control of the cold pressing equipment, ensure the consistency of the entire roll of electrode sheets, and reduce the risk of batch defects, in this embodiment, the elongation rate of each region is first calculated based on the first film width of multiple regions in the image before alignment and before rolling and the second film width of the same region in the image after alignment and after rolling. Then, the first elongation rate of the electrode sheet in the direction perpendicular to the belt conveyor is calculated based on the elongation rate of each region.

[0295] For ease of understanding, please refer to Figure 4 This explanation is provided, but does not limit the scope of this application. Figure 4 The diagram below illustrates the film widths of some embodiments of the present invention. As an example, the film widths D11, D12, D13, D21, D22, D23, D31, D32, and D33 of each region are taken at 0.25*L1, 0.5*L1, and 0.75*L1, respectively (e.g., ...). Figure 4 As shown in the figure); similarly, the dimensions D11', D12', D13', D21', D22', D23', D31', D32', and D33' (not shown in the figure) of each region after cold pressing are calculated based on the image after alignment and rolling. Assuming that in the image before alignment and rolling, the first film widths of the three sub-regions in the left area of ​​the electrode are: D11=200mm (left area 1), D21=200mm (left area 2), and D31=200mm (left area 3); and in the image after alignment and rolling, the second film widths of the same three sub-regions in the left area are: D11'=200.2mm, D21'=200.3mm, and D31'=200.1mm; (the corresponding film widths for the middle and right areas are obtained similarly; the left area is used as an example here). Based on the above film widths of the three sub-regions in the left area, the elongation δ of left area 1 can be calculated. D 11 = (200.2 - 200) / 200 × 100% = 0.1%; Left zone 2 elongation δ D 21 = (200.3 - 200) / 200 × 100% = 0.15%; Left zone 3 elongation δ D 31 = (200.1 - 200) / 200 × 100% = 0.05%; (The same calculation applies to the sub-regions of the central and right regions. For example, the elongation rates of the three sub-regions in the central region are 0.12%, 0.08%, and 0.11%, respectively; and in the right region, they are 0.09%, 0.13%, and 0.10%). The specific formula for calculating the first elongation rate of the electrode in the direction perpendicular to the travel direction based on the elongation rates of the above nine sub-regions is as follows:

[0296] δ D =(δ D 11+δ D 21+δ D 31+δ D 12+δ D 22+δD 32+δ D 13+δ D 23+δ D 33) / 9 = (0.1%+0.15%+0.05%+0.12%+0.08%+0.11%+0.09%+0.13%+0.10%) / 9 = 0.103%.

[0297] This embodiment first calculates the elongation of each region based on the first film width of multiple regions in the image before alignment and before rolling, and the second film width of the same region in the image after alignment and after rolling. Then, it calculates the first elongation of the electrode sheet in the direction perpendicular to the conveyor belt based on the elongation of each region. This can reflect the overall cold pressing elongation level of the electrode sheet, avoid misjudgment caused by the partiality of local data, provide a global reference for the closed-loop control of the cold pressing equipment, ensure the consistency of the entire roll of electrode sheets, and reduce the risk of batch defects.

[0298] In some embodiments, such as Figure 16 As shown, after step S20, the method further includes:

[0299] Step S30': In response to the pulse, the belt speed before the electrode is rolled is acquired.

[0300] Step S40': In response to the pulse, the belt speed after the electrode sheet is rolled is collected.

[0301] Step S50': Calculate the second elongation of the electrode sheet in the belt travel direction based on the belt travel speed before and after the roll forming.

[0302] To reduce the cost of detecting the second elongation of the electrode in the belt-carrying direction and avoid damaging the electrode, in this embodiment, a third detection module and a fourth detection module are respectively set on both sides of the roll. The third detection module and the fourth detection module detect the belt-carrying speed of the electrode before and after rolling, respectively, and calculate the second elongation of the electrode in the belt-carrying direction based on the belt-carrying speed before and after rolling.

[0303] The third detection module can be a Doppler laser velocimeter installed on the feed side of the cold press rolls. It uses non-contact laser interferometry to collect the real-time belt speed (V0) of the electrode sheet before it enters the rolls. The fourth detection module can be a Doppler laser velocimeter of the same model installed on the discharge side of the rolls, forming a "front-to-back" speed measurement system with the third module to collect the belt speed (V1) of the electrode sheet after rolling. Both modules must be strictly aligned with the electrode sheet centerline to ensure that the speed change is measured in the same film area.

[0304] For ease of understanding, please refer to Figure 3 and Figure 5 This explanation is provided, but does not limit the scope of this application. Figure 3 These are top views of the electrode rolling process in some embodiments of the present invention. Figure 5 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention. As an example, a roll 20 presses an electrode sheet, which moves along the belt feed direction. The movement of the electrode sheet triggers an encoder 40 to emit a pulse signal. This same pulse signal is split into four parts and sent to the first detection module 10, the second detection module 30, the third detection module 60, and the fourth detection module 70, respectively. This ensures that the first detection module 10 and the second detection module 30 take photos simultaneously, and that the third detection module 60 and the fourth detection module 70 measure speed simultaneously. The first detection module 10 and the second detection module 30 detect the first elongation δ of the electrode sheet in the direction perpendicular to the belt feed direction. D The specific steps have been explained above and will not be repeated here. Since the third detection module 60 and the fourth detection module 70 are respectively located on both sides of the roll 20, the speeds obtained when the third detection module 60 and the fourth detection module 70 measure speed synchronously are not the speeds of the same area of ​​the electrode sheet. To overcome the above defects, this embodiment uses frame alignment to ensure that the speeds measured by the two detection modules are the same area of ​​the electrode sheet before and after rolling. The specific steps of frame alignment are as follows: the control module 50 obtains the interval pulse number S of the speed measurement of the same area of ​​the electrode sheet by the third detection module 60 and the fourth detection module 70 (i.e., when the same area of ​​the electrode sheet moves from the image acquisition position corresponding to the third detection module 60 to the image acquisition position corresponding to the fourth detection module 70, the encoder 40 generates pulses), uses the speed measured by the fourth detection module as the belt speed V1 after rolling, and uses the speed measured by the third detection module before S pulses as the belt speed V0 before rolling. The interval pulse number S can be preset or calculated based on the actual parameters of the elongation monitoring system; this embodiment does not impose any restrictions on this. Figure 3 As shown, after obtaining the belt speed before and after rolling, the control module 50 calculates the second elongation δ of the electrode in the belt-carrying direction based on the belt speed before and after rolling. L The specific calculation formula is as follows:

[0305] δ L =(L'-L) / L)*100%=(V1*T-V0*T) / V0*T*100%=(V1-V0) / V0*100%

[0306] In the formula, δ L L represents the second elongation of the electrode sheet in the belt-carrying direction, L represents the length of the electrode sheet before rolling in the belt-carrying direction, L' represents the length of the electrode sheet after rolling in the belt-carrying direction, V0 represents the belt-carrying speed before rolling, and V1 represents the belt-carrying speed after rolling.

[0307] This embodiment detects the belt speed before and after rolling of the electrode sheet, and calculates the second elongation of the electrode sheet in the belt-carrying direction based on the belt speed before and after rolling. Therefore, the second elongation of the electrode sheet in the belt-carrying direction can be calculated without marking the electrode sheet, thereby reducing the detection cost of the second elongation and avoiding damage to the electrode sheet.

[0308] In some embodiments, such as Figure 17 As shown, step S30' includes:

[0309] Step S301': In response to the pulse, a first interference laser and a second interference laser are simultaneously emitted toward the electrode, wherein the first interference laser and the second interference laser form a first Newton's ring on the electrode.

[0310] Step S302': Obtain the width of the first Newton's rings, and calculate the rolling speed of the electrode sheet based on the width of the first Newton's rings, the angle between the first interference laser and the second interference laser, and the detection frequency of the rolling speed.

[0311] To improve the measurement accuracy of the belt speed before rolling, in this embodiment, a first interference laser and a second interference laser are simultaneously emitted to the electrode, and the belt speed before rolling is calculated by a preset algorithm based on the first Newton's rings formed on the electrode by the first and second interference lasers.

[0312] The first and second interferometric lasers are two co-originating lasers emitted by the third detection module, serving as the core light source for Doppler velocimetry. The two lasers have a fixed angle (denoted as k, a pre-defined value from the hardware), the same wavelength (denoted as λ), and both are emitted perpendicular to the electrode's travel plane, working together to create an interference effect on the electrode surface. The first Newton's rings refer to the alternating bright and dark fringes generated by the optical path difference after the first and second interferometric lasers intersect on the electrode surface; these are invisible to the naked eye and must be detected by a photodiode built into the module. The fringe spacing (denoted as d) is directly related to the laser wavelength and the angle between the two lasers, and changes inversely with the electrode's travel speed (the faster the speed, the higher the fringe movement frequency, and the spacing indirectly reflects the speed characteristics).

[0313] In the specific implementation, the photodiode built into the third detection module captures the reflected signal of the first Newton's rings in real time, and the detection frequency f is calculated by back-calculating the signal period (t). The width d of Newton's rings is calculated based on hardware parameters. Different speeds will cause the width d of Newton's rings to change. Given λ (laser wavelength) and k (angle between the two laser beams), substitute them into the formula. We obtain d. Combined with the formula for the detection frequency f... Calculate the belt speed V0 before the electrode is rolled (where, Constant coefficients for module factory calibration, such as ).

[0314] This embodiment simultaneously emits a first interference laser and a second interference laser onto the electrode, and calculates the belt speed of the electrode before rolling by using a preset algorithm based on the first Newton's rings formed on the electrode by the first and second interference lasers. This improves the measurement accuracy of the belt speed before rolling, and further improves the accuracy of the second elongation rate.

[0315] In some embodiments, such as Figure 18 As shown, step S40' includes:

[0316] Step S401': In response to the pulse, a third interference laser and a fourth interference laser are simultaneously emitted toward the electrode, wherein the third interference laser and the fourth interference laser form a second Newton's ring on the electrode.

[0317] Step S402': Obtain the width of the second Newton's rings, and calculate the rolling speed of the electrode sheet based on the width of the second Newton's rings, the angle between the third interference laser and the fourth interference laser, and the detection frequency of the rolling speed.

[0318] To improve the measurement accuracy of the belt speed after rolling, in this embodiment, a third interference laser and a fourth interference laser are simultaneously emitted to the electrode, and the belt speed after rolling is calculated by a preset algorithm based on the second Newton's rings formed on the electrode by the third and fourth interference lasers.

[0319] The third and fourth interferometric lasers are two co-originating, same-wavelength lasers emitted by the fourth detection module, serving as the core light source for Doppler velocimetry. The two lasers have a fixed angle (denoted as k, consistent with the laser angle of the third module, a pre-defined known quantity in the hardware), a fixed wavelength (denoted as λ), and their emission direction is strictly perpendicular to the electrode's conveyor plane. Together, they act on the rolled electrode surface, creating an interference effect. The second Newton's rings refer to the alternating bright and dark fringes generated by the optical path difference after the third and fourth interferometric lasers intersect on the rolled electrode surface. These are invisible to the naked eye and must be captured by the module's built-in photodiode. The fringe spacing (denoted as d) is directly related to the laser wavelength (λ) and the angle (k) between the two lasers. In the specific implementation, the method for calculating the conveyor speed after rolling is similar to that before rolling, and will not be elaborated here.

[0320] This embodiment simultaneously emits a third interference laser and a fourth interference laser onto the electrode, and calculates the belt speed of the electrode after rolling by using a preset algorithm based on the second Newton's rings formed on the electrode by the third and fourth interference lasers. This improves the measurement accuracy of the belt speed after rolling, and further improves the accuracy of the second elongation rate.

[0321] In some embodiments, after calculating the first elongation of the electrode sheet in the direction perpendicular to the belt feed based on the pre-rolling image and the post-rolling image, the method further includes: calculating the pre-rolling film width of the electrode sheet in the direction perpendicular to the belt feed based on the pre-rolling image, and calculating the post-rolling film width of the electrode sheet in the direction perpendicular to the belt feed based on the post-rolling image; calculating the pre-rolling length of the electrode sheet in the belt feed direction based on the pre-rolling belt feed speed, and calculating the post-rolling length of the electrode sheet in the belt feed direction based on the post-rolling belt feed speed; and calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length.

[0322] In order to calculate the surface elongation of the electrode sheet and better reflect the consistency of the battery cell production, in this embodiment, the film width of the electrode sheet before and after rolling is calculated based on the images before and after rolling, respectively, in the direction perpendicular to the belt feeding direction. Then, the length of the electrode sheet before and after rolling is calculated based on the belt feeding speed before and after rolling. Finally, the surface elongation of the electrode sheet is calculated based on the film width and length before and after rolling.

[0323] For ease of understanding, please refer to Figure 3 This explanation is provided, but does not limit the scope of this application. Figure 3 These are top views of the electrode before and after rolling according to some embodiments of the present invention. As an example, the pre-rolling film width D of the electrode in the direction perpendicular to the belt conveyor is calculated based on the pre-rolling image, the post-rolling film width D' of the electrode in the direction perpendicular to the belt conveyor is calculated based on the post-rolling image, the pre-rolling length L of the electrode in the belt conveyor direction is calculated based on the pre-rolling belt conveyor speed, and the post-rolling length L' of the electrode in the belt conveyor direction is calculated based on the post-rolling belt conveyor speed. Then, the formula for calculating the surface elongation δ is: δ=(D'*L' / D*L)-1, where δ is the surface elongation, D' is the post-rolling film width, L' is the post-rolling length, D is the pre-rolling film width, and L is the pre-rolling length.

[0324] In this embodiment, the film width of the electrode sheet before and after rolling is calculated based on the images before and after rolling, respectively, in the direction perpendicular to the belt feeding direction. Then, the length of the electrode sheet before and after rolling is calculated based on the belt feeding speed before and after rolling. Finally, the surface elongation of the electrode sheet is calculated based on the film width and length before and after rolling, thereby enabling the calculation of the surface elongation of the electrode sheet and better reflecting the consistency of battery cell production.

[0325] In some embodiments, after calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length, the method further includes: calculating an adjustment amount during electrode sheet rolling based on the elongation, wherein the elongation includes at least one of the first elongation, the second elongation, and the surface elongation; and adjusting the rolling parameters during electrode sheet rolling based on the adjustment amount.

[0326] In order to reduce the number of electrodes with poor elongation at the source, avoid batch events, and form a closed loop, the elongation monitoring system in this embodiment also includes: a rolling mill host. The rolling mill host calculates the adjustment amount of the rolling mill according to the elongation and adjusts the rolling pressure parameters of the rolling mill according to the adjustment amount, so as to optimize the rolling pressure parameters of the rolling mill in real time and bring the elongation of the electrode back to the qualified range.

[0327] The adjustment amount refers to the specific values ​​(such as pressure change, roll gap adjustment, angle adjustment, etc.) that the rolling mill needs to adjust the rolling parameters to bring the elongation back to the qualified range. It is calculated from the deviation of the elongation from the preset qualified range. Rolling parameters refer to the key operating parameters of the rolling mill during the cold pressing process, mainly including rolling pressure (the pressure applied to the electrode), roll gap (the gap between two rolling mills), and angle (the angle between two rolling mills), which directly affect the cold pressing elongation of the electrode.

[0328] For ease of understanding, please refer to Figure 6 This explanation is provided, but does not limit the scope of this application. Figure 6 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 6 In the process, after calculating the overall elongation and elongation of each region of the electrode sheet, the control module 50 transmits this data to the control interface of the rolling mill 80 in real time. The transmission method is electrical signal (such as analog or digital signal), ensuring that the data delay is less than 100ms, so that the rolling mill 80 can obtain the current elongation status in a timely manner. After receiving the elongation data, the rolling mill host 80 calculates the adjustment amount through its built-in algorithm: if the elongation is higher than the upper limit (e.g., 0.18% > 0.15%), it indicates that the rolling pressure is too high (the higher the pressure, the more obvious the electrode elongation), and the pressure needs to be reduced. The adjustment amount is "current pressure - pressure value corresponding to the deviation" (e.g., a deviation of 0.03% corresponds to a pressure reduction of 5kN); if the elongation is lower than the lower limit (e.g., 0.03% < 0.05%), it indicates that the pressure is too low, and the pressure needs to be increased. The adjustment amount is "current pressure + pressure value corresponding to the deviation". The main adjustment parameter is the rolling pressure (achieved through the hydraulic system). If necessary, the roll gap (distance between two rolls) and angle (angle between two rolls) are adjusted as auxiliary parameters. The adjustment process is carried out in steps (e.g., adjusting 2kN each time to avoid sudden parameter changes).

[0329] This embodiment calculates the adjustment amount of the roll based on the elongation rate, and adjusts the roll pressure parameters of the roll based on the adjustment amount to optimize the roll pressure parameters of the roll in real time, so that the elongation rate of the electrode sheet returns to the qualified range. This enables the real-time optimization of the roll pressure parameters of the roll, so that the elongation rate of the electrode sheet returns to the qualified range, thereby reducing the number of electrodes with poor elongation rate from the source, avoiding batch events, and forming a closed loop.

[0330] In some embodiments, calculating the adjustment amount when rolling the electrode based on the elongation rate includes: calculating the elongation rate difference between the elongation rate and a preset elongation rate threshold; and calculating the adjustment amount when rolling the electrode based on the elongation rate difference.

[0331] To improve the accuracy of the adjustment amount, this embodiment calculates the adjustment amount of the roll based on the difference between the elongation rate and the preset elongation rate threshold, and to avoid over-adjustment and reduce elongation rate fluctuations. In this embodiment, the roll pressure parameters of the roll are adjusted according to the adjustment amount and a preset adjustment step.

[0332] The preset elongation threshold can include an upper and lower limit for elongation, which are pre-existing acceptable range standards in the rolling mill's process parameter library. These must be set according to the electrode type (cathode / anode), specifications, and process objectives. The elongation difference refers to the deviation between the actual elongation calculated by the rolling mill and the preset threshold. It falls into two scenarios: If the actual elongation > the upper threshold: difference = actual elongation - upper threshold (e.g., actual 1.8%, upper limit 1.5%, difference 0.3%); if the actual elongation < the lower threshold: difference = lower threshold - actual elongation (e.g., actual 0.3%, lower limit 0.5%, difference 0.2%). The magnitude of the difference directly determines the calculation of the adjustment amount and is the core basis for triggering roll pressure parameter adjustments. The preset adjustment step refers to the smallest unit of adjustment per cycle, used to avoid excessive adjustment at once that could cause the elongation to exceed the limit. The step value can be set according to the electrode material characteristics to ensure a smooth and controllable adjustment process.

[0333] This embodiment calculates the adjustment amount of the roll based on the difference between the elongation rate and the preset elongation rate threshold, thereby improving the accuracy of the adjustment amount. Furthermore, the roll pressure parameters of the roll are adjusted according to the preset adjustment steps based on the adjustment amount, thereby avoiding over-adjustment and reducing elongation rate fluctuations.

[0334] In some embodiments, calculating the adjustment amount when rolling the electrode sheet based on the elongation includes: obtaining the current rolling angle of the roll that rolls the electrode sheet; and calculating the rolling angle adjustment amount of the roll based on the elongation and the current rolling angle.

[0335] In order to achieve precise local pressure control in the width direction and solve the problem of unevenness caused by overall pressure adjustment (such as reducing the overall pressure to make the right area qualified but the left area lower), and improve the consistency of the elongation of the entire electrode sheet, in this embodiment, the rolls include: a first roll and a second roll. The roll angle of the second roll and / or the first roll can also be adjusted according to the elongation and the current roll angle of the first roll and / or the second roll.

[0336] The first roll can refer to the cylindrical roll located on one side of the electrode sheet (as shown above) in the rolling mill, which works in conjunction with the second roll to apply pressure to the electrode sheet and is one of the core components in the cold pressing process. The second roll can refer to the cylindrical roll located on the other side of the electrode sheet (as shown below) in the rolling mill, corresponding to the first roll, together forming the working area for cold pressing the electrode sheet. Cold pressing of the electrode sheet is achieved through relative rotation and pressure application. The corresponding arrangement can mean that the centerlines of the first roll and the second roll are parallel and the distance between them is adjustable, and the roll surfaces face each other to form a roll gap (the gap between the two rolls) for the electrode sheet to pass through, ensuring that the electrode sheet can be uniformly pressed. The current roll pressure angle can refer to the tilt angle of the first roll and / or the second roll relative to a reference position (such as horizontal or vertical direction), reflecting the pressure distribution state of the roll in the axial direction (TD direction) (changes in angle will cause changes in the uniformity of the roll gap in the width direction). The roll angle adjustment amount refers to the angle value (unit: degree or minute) that needs to be adjusted to bring the electrode elongation back to the qualified range. It is calculated by combining the elongation deviation and the current angle.

[0337] For ease of understanding, please refer to Figure 7 This explanation is provided, but does not limit the scope of this application. Figure 7 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 7 In this rolling mill, the core components are a pair of first rolls (upper roll) 21 and second rolls (lower roll) 22, with their centerlines parallel and correspondingly distributed in the vertical direction (the electrode passes through the roll gap between the two rolls). The rolling mill host 80 collects the current roll pressure angle of the first roll 21 and / or the second roll 22 in real time through angle sensors (such as encoders or inclinometers) installed at the ends of the roll shafts. This angle reflects whether the rolls are in a horizontal reference position (0°): if the angle is 0°, the two rolls are completely parallel, and the pressure is uniform in the width direction; if the angle deviates from 0° (such as the right end of the first roll 21 tilting upward by 0.5°), the roll gap will be narrower on the left and wider on the right in the width direction, resulting in greater pressure on the left side of the electrode than on the right side, and a higher elongation in the left side than on the right side. The current angle data is transmitted to the control unit of the rolling mill host in real time as a basis for adjustment.

[0338] The control unit of the rolling mill 80 has a built-in algorithm that calculates the adjustment amount based on the elongation deviation of each region of the electrode sheet (the difference from the target value) and the current roll pressure angle. If the elongation of a certain region is higher than the target value (e.g., 0.18% in the right region > 0.15% of the target), and the current angle shows that the roll in that region is tilted, resulting in excessive pressure (e.g., the second roll 22 tilts to the right, making the roll gap in the right region narrow), then the angle needs to be adjusted in the opposite direction (e.g., the right end of the second roll 22 is adjusted upward by 0.1°) to increase the roll gap in that region and reduce the pressure. If the elongation of a certain region is lower than the target value (e.g., 0.08% in the left region < 0.12% of the target), and the current angle shows insufficient pressure, then the angle needs to be adjusted in the positive direction (e.g., the left end of the first roll 21 is adjusted downward by 0.05°) to reduce the roll gap and increase the pressure. The adjustment amount needs to be accurately calculated based on the elongation deviation and the influence coefficient of the angle on the pressure (e.g., 0.1° angle corresponds to a 0.03% change in elongation) to ensure that the elongation returns to the target range after adjustment.

[0339] This embodiment calculates the adjustment amount of the rolling angle of the rollers for rolling the electrode sheet based on the current rolling angle of the rollers and the elongation rate. This achieves precise local pressure control in the width direction, thereby avoiding the problem of uneven regional elongation rate caused by overall pressure adjustment and improving the consistency of the elongation rate of the entire electrode sheet.

[0340] In some embodiments, after calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length, the method further includes: generating an alarm command if the elongation does not meet a preset specification; stopping the rolling process according to the alarm command; and generating a prompt message corresponding to the alarm command.

[0341] To achieve automatic identification and command triggering of anomalies, avoid the lag and misjudgment of manual judgment, ensure the timeliness and accuracy of alarm actions, and buy time for subsequent shutdown and processing, thereby reducing the risk of batch defects from a mechanism perspective, in this embodiment, the elongation monitoring system also includes an alarm module. The alarm module stops the rolling process according to the alarm command and generates the corresponding prompt information.

[0342] An alarm module can refer to a component (such as an audible and visual alarm or a shutdown control unit) that receives alarm commands from the control module, executes shutdown operations, and generates prompt information. It serves as an emergency response device when the elongation rate is abnormal. A preset specification refers to a pre-defined acceptable elongation rate range (e.g., 0.05%-0.15%), determined by process requirements, and is the basis for the control module to determine whether the elongation rate is abnormal. An alarm command is an electrical signal sent by the control module to the alarm module when the elongation rate does not meet the preset specification. This signal includes information such as the abnormal area and the out-of-tolerance value, triggering the alarm module's action. Prompt information refers to text, audible, and visual prompts generated by the alarm module based on the alarm command (e.g., "Right zone 2 elongation rate exceeds upper limit" or "Please check roll pressure"), used to inform operators of the cause of the abnormality and the appropriate course of action.

[0343] For ease of understanding, please refer to Figure 7 This explanation is provided, but does not limit the scope of this application. Figure 7 This is a schematic diagram of an elongation monitoring system according to some embodiments of the present invention, as an example. Figure 7 In the process, the control module 50 compares the calculated elongation rate of each region and the overall elongation rate with the preset specifications (e.g., 0.05%-0.15%) in real time. If the elongation rate of any region is ≥0.05% and ≤0.15%, it is determined to "meet the preset specifications," and the elongation rate is sent to the rolling host so that the rolling host can calculate the adjustment amount of the roll based on the elongation rate and adjust the rolling parameters of the roll according to the adjustment amount. If the elongation rate of any region is <0.05% (below the lower limit) or >0.15% (above the upper limit), it is determined to "not meet the preset specifications." At this time, the control module immediately generates an alarm command, including information such as the out-of-tolerance region (e.g., "Right Zone 2"), the out-of-tolerance value (e.g., "0.18%)", and the out-of-tolerance type ("above the upper limit"), and sends it to the alarm module 100 through wired communication (e.g., signal line). After receiving the alarm command from the control module, the alarm module 100 performs two core operations:

[0344] 1. Stop rolling: Cut off the drive power of the rolls through the stop control unit, so that the first and second rolls stop rotating, the movement of the electrode sheets is interrupted, and the out-of-tolerance area is prevented from continuing to be cold-pressed and flowing into the next process;

[0345] 2. Generate prompt information: Based on the out-of-tolerance area and value in the instruction, control the action of the sound and light alarm device (such as flashing warning light and buzzer sounding), and at the same time pop up a text prompt on the display module (such as "Right zone 2 elongation exceeds the upper limit by 0.03%, the machine has been stopped, please check the pressure of the right zone of the roll") to guide the operator to troubleshoot the problem (such as roll angle deviation, abnormal pressure).

[0346] This embodiment stops the rolling process according to the alarm command and generates a prompt message corresponding to the alarm command, thereby enabling automatic identification of abnormalities and command triggering, avoiding the lag and misjudgment of manual judgment, ensuring the timeliness and accuracy of alarm actions, and buying time for subsequent shutdown and processing, thus reducing the risk of batch defects from a mechanism perspective.

[0347] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A system for monitoring elongation, characterized in that, The elongation monitoring system includes: a first detection module, a roll, a second detection module, an encoder, and a control module; The roller is used to roll and press the electrode sheet, which moves along the belt conveyor direction. The first detection module is located on one side of the roller, and the second detection module is located on the other side of the roller. The encoder is used to trigger pulses when the pole piece moves; The first detection module is used to respond to the pulse, acquire an image of the electrode before rolling, and send the image to the control module. The second detection module is used to respond to the pulse, acquire the rolled image of the electrode sheet, and send the rolled image to the control module; The control module is used to perform image frame alignment on the image before rolling and the image after rolling, and to calculate the first elongation rate of the electrode in the direction perpendicular to the belt conveyor based on the aligned image before rolling and the aligned image after rolling. The image frame alignment is used to ensure that the image acquisition area of ​​the aligned image before rolling and the image acquisition area of ​​the aligned image after rolling correspond to the same area of ​​the electrode. The control module is further configured to obtain the actual interval distance between the first detection module and the second detection module, and to obtain the actual shooting area length corresponding to a single image, wherein an integer multiple of the actual shooting area length is the actual interval distance; The control module is also used to obtain the total number of pulses required to capture a single image; The control module is also used to calculate the number of interval pulses between the first detection module and the second detection module when they capture the same area of ​​the electrode sheet based on the actual interval distance, the actual shooting area length, and the total number of pulses; The control module is also used to perform image frame alignment between the pre-rolling image and the post-rolling image based on the number of interval pulses.

2. The elongation monitoring system as described in claim 1, characterized in that, The first detection module and the second detection module are line scan cameras; The control module is further configured to obtain the single-pixel accuracy of the first detection module and the second detection module and the number of pulses required to trigger the shooting of a single row of pixels, wherein the single-pixel accuracy represents the actual physical length corresponding to a single row of pixels; The control module is also used to calculate the total number of pulses required to capture a single image based on the number of pulses, the single pixel accuracy, and the actual shooting area length.

3. The elongation monitoring system as described in claim 2, characterized in that, The single-pixel accuracy is less than a preset threshold, wherein the preset threshold is determined in advance based on the measurement elongation accuracy.

4. The elongation monitoring system as described in claim 1, characterized in that, The control module is also used to obtain the first film width of multiple regions in the image before alignment and rolling, and to obtain the second film width of the same region in the image after alignment and rolling. The control module is also used to calculate the elongation of each region based on the first film width and the second film width; The control module is also used to calculate the first elongation of the electrode in the direction perpendicular to the tape delivery based on the elongation of each region.

5. The elongation monitoring system as described in claim 1, characterized in that, The first detection module and the second detection module are large field-of-view macro cameras. The field of view of the large field-of-view macro camera is larger than the width of the electrode, and the working distance of the large field-of-view macro camera is less than a preset distance.

6. The elongation monitoring system as described in any one of claims 1 to 5, characterized in that, The elongation monitoring system further includes a third detection module and a fourth detection module, wherein the third detection module is disposed on one side of the roll and the fourth detection module is disposed on the other side of the roll. The third detection module is used to respond to the pulse, collect the belt speed before the rolling of the electrode sheet, and send the belt speed before the rolling to the control module; The fourth detection module is used to respond to the pulse, collect the belt speed after the electrode is rolled, and send the belt speed after the roller is rolled to the control module; The control module is used to calculate the second elongation of the electrode sheet in the belt-carrying direction based on the belt-carrying speed before and after the roll-pressing.

7. The elongation monitoring system as described in claim 6, characterized in that, The third detection module is also used to respond to the pulse by simultaneously emitting a first interference laser and a second interference laser toward the electrode, wherein the first interference laser and the second interference laser intersect on the surface of the electrode and produce alternating bright and dark stripes due to the optical path difference; The third detection module is also used to obtain the stripe spacing, calculate the pre-rolling speed of the electrode based on the stripe spacing, the angle between the first interference laser and the second interference laser, and the detection frequency of the third detection module, and send the pre-rolling speed to the control module.

8. The elongation monitoring system as described in claim 7, characterized in that, The fourth detection module is also used to respond to the pulse by simultaneously emitting a third interference laser and a fourth interference laser to the electrode, wherein the third interference laser and the fourth interference laser intersect on the surface of the rolled electrode, resulting in alternating bright and dark stripes due to the optical path difference; The fourth detection module is also used to obtain the stripe spacing, and calculate the belt speed of the electrode after rolling based on the stripe spacing, the angle between the third interference laser and the fourth interference laser, and the detection frequency of the fourth detection module, and send the belt speed after rolling to the control module.

9. The elongation monitoring system as described in claim 6, characterized in that, The elongation monitoring system further includes: a first heat dissipation module corresponding to the third detection module and a second heat dissipation module corresponding to the fourth detection module; The first heat dissipation module is used to isolate the heat generated by the electrode rolling process from the third detection module and / or to dissipate heat from the third detection module; The second heat dissipation module is used to isolate the heat generated by the electrode rolling process from the fourth detection module and / or to dissipate heat from the fourth detection module.

10. The elongation monitoring system as described in claim 6, characterized in that, The control module is further configured to calculate the pre-rolling film width of the electrode sheet in the direction perpendicular to the belt feed based on the pre-rolling image, and to calculate the post-rolling film width of the electrode sheet in the direction perpendicular to the belt feed based on the post-rolling image. The control module is also used to calculate the length of the electrode sheet before rolling in the belt-carrying direction based on the belt-carrying speed before rolling, and to calculate the length of the electrode sheet after rolling in the belt-carrying direction based on the belt-carrying speed after rolling. The control module is also used to calculate the surface elongation of the electrode sheet based on the film width before rolling, the film width after rolling, the length before rolling, and the length after rolling.

11. The elongation monitoring system as described in claim 10, characterized in that, The elongation monitoring system also includes: a rolling mill main unit; The control module is further configured to send the elongation rate to the rolling host, wherein the elongation rate includes at least one of the first elongation rate, the second elongation rate, and the surface elongation rate; The rolling mill host is used to calculate the adjustment amount of the rolling mill based on the elongation rate, and adjust the rolling pressure parameters of the rolling mill based on the adjustment amount.

12. The elongation monitoring system as described in claim 11, characterized in that, The rolling mill host is also used to calculate the difference between the elongation rate and the preset elongation rate threshold, and to calculate the adjustment amount of the rolling mill based on the elongation rate difference; The rolling mill host is also used to adjust the rolling pressure parameters of the rolling mill according to the adjustment amount and a preset adjustment step.

13. The elongation monitoring system as described in claim 11, characterized in that, The rolls include: a first roll and a second roll, wherein the first roll and the second roll are arranged correspondingly; The rolling mill host is also used to obtain the current rolling angle of the first rolling mill and / or the second rolling mill; The rolling mill host is also used to calculate the adjustment amount of the rolling angle of the second roll and / or the first roll based on the elongation and the current rolling angle.

14. The elongation monitoring system as described in claim 11, characterized in that, The elongation monitoring system also includes: a display module; The control module is also used to send the elongation rate to the display module; The display module is used to receive the stretch rate sent by the control module and display the stretch rate.

15. The elongation monitoring system as described in claim 11, characterized in that, The elongation monitoring system also includes: an alarm module; The control module is also used to send an alarm command to the alarm module when the elongation does not meet the preset specifications; The alarm module is used to stop the rolling process according to the alarm command and generate a prompt message corresponding to the alarm command.

16. The elongation monitoring system as described in any one of claims 1 to 5, characterized in that, The elongation monitoring system also includes: the encoder roller corresponding to the encoder; The encoder roller is used to rotate in response to the movement of the electrode sheet, and the rotation of the encoder roller drives the encoder to trigger pulses.

17. The elongation monitoring system as described in claim 16, characterized in that, The encoding roller is an active roller; The active roller is used to drive the electrode sheet to move by actively rotating, and to drive the encoder to trigger pulses.

18. A method for monitoring elongation, characterized in that, include: Roll-pressed electrode sheets, which move along the belt conveyor direction; A pulse is triggered when the electrode moves; In response to multiple pulses, an image of the electrode sheet before rolling is acquired; In response to multiple pulses, images of the electrode sheet after rolling are acquired; Image frames are aligned between the pre-rolling image and the post-rolling image, and the first elongation of the electrode sheet in the direction perpendicular to the belt conveyor is calculated based on the aligned pre-rolling image and the aligned post-rolling image. The image frame alignment is used to ensure that the image acquisition area of ​​the aligned pre-rolling image and the image acquisition area of ​​the aligned post-rolling image correspond to the same area of ​​the electrode sheet. The step of aligning the image frames of the image before and after rolling includes: The actual interval distance between the acquisition position of the image before rolling and the acquisition position of the image after rolling is obtained, and the actual shooting area length corresponding to a single image is obtained, wherein an integer multiple of the actual shooting area length is the actual interval distance; Obtain the total number of pulses required to capture a single image; The number of interval pulses between the first detection module corresponding to the image before rolling and the second detection module corresponding to the image after rolling is calculated based on the actual interval distance, the actual shooting area length, and the total number of pulses. Image frames are aligned between the pre-rolling and post-rolling images based on the number of interval pulses.

19. The elongation monitoring method as described in claim 18, characterized in that, The total number of pulses required to acquire a single image includes: The single-pixel precision and the number of pulses required to trigger the capture of a single row of pixels are obtained for capturing the images before and after the rolling process, wherein the single-pixel precision represents the actual physical length corresponding to a single row of pixels; The total number of pulses required to capture a single image is calculated based on the pulse count, the single-pixel precision, and the actual shooting area length.

20. The elongation monitoring method as described in claim 18, characterized in that, The step of calculating the first elongation of the electrode sheet in the direction perpendicular to the belt conveyor based on the image before and after alignment and rolling includes: Obtain the first film width of multiple regions in the image before alignment and roll pressing, and obtain the second film width of the same region in the image after alignment and roll pressing; Calculate the elongation of each region based on the first film width and the second film width; The first elongation of the electrode in the direction perpendicular to the travel strip is calculated based on the elongation of each region.

21. The elongation monitoring method according to any one of claims 18 to 20, characterized in that, After triggering the pulse when the electrode moves, the method further includes: In response to the pulse, the belt speed before the electrode is rolled is acquired; In response to the pulse, the belt speed of the electrode sheet after rolling is collected; The second elongation of the electrode sheet in the belt-carrying direction is calculated based on the belt-carrying speed before and after the roll forming.

22. The elongation monitoring method as described in claim 21, characterized in that, The step of acquiring the belt speed before rolling the electrode in response to the pulse includes: In response to the pulse, a first interference laser and a second interference laser are simultaneously emitted toward the electrode, wherein the first interference laser and the second interference laser intersect on the surface of the electrode and produce alternating bright and dark stripes due to the optical path difference; The fringe spacing is obtained, and the pre-rolling speed of the electrode is calculated based on the fringe spacing, the angle between the first interference laser and the second interference laser, and the detection frequency of the pre-rolling speed.

23. The elongation monitoring method as described in claim 21, characterized in that, The step of collecting the belt speed of the electrode after rolling in response to the pulse includes: In response to the pulse, a third interference laser and a fourth interference laser are simultaneously emitted toward the electrode. The third interference laser and the fourth interference laser intersect on the surface of the rolled electrode, resulting in alternating bright and dark stripes due to the optical path difference. The stripe spacing is obtained, and the stripe speed after rolling is calculated based on the stripe spacing, the angle between the third interference laser and the fourth interference laser, and the detection frequency of the belt speed after rolling.

24. The elongation monitoring method as described in claim 21, characterized in that, After calculating the first elongation of the electrode sheet in the direction perpendicular to the belt conveyor based on the pre-rolling image and the post-rolling image, the method further includes: The pre-rolling film width of the electrode sheet in the direction perpendicular to the belt feed is calculated based on the pre-rolling image, and the post-rolling film width of the electrode sheet in the direction perpendicular to the belt feed is calculated based on the post-rolling image. The length of the electrode sheet before rolling in the belt-carrying direction is calculated based on the belt-carrying speed before rolling, and the length of the electrode sheet after rolling in the belt-carrying direction is calculated based on the belt-carrying speed after rolling. The surface elongation of the electrode sheet is calculated based on the film width before rolling, the film width after rolling, the length before rolling, and the length after rolling.

25. The elongation monitoring method as described in claim 24, characterized in that, After calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length, the method further includes: The adjustment amount during the rolling of the electrode sheet is calculated based on the elongation rate, wherein the elongation rate includes at least one of the first elongation rate, the second elongation rate, and the surface elongation rate; Adjust the rolling pressure parameters when rolling the electrode sheet according to the adjustment amount.

26. The elongation monitoring method as described in claim 25, characterized in that, The adjustment amount for calculating the electrode rolling based on the elongation includes: Calculate the difference between the elongation rate and the preset elongation rate threshold; The adjustment amount during electrode rolling is calculated based on the difference in elongation.

27. The elongation monitoring method as described in claim 25, characterized in that, The adjustment amount for calculating the electrode rolling based on the elongation includes: Obtain the current rolling angle of the rolls that roll the electrode sheet; The roll angle adjustment amount is calculated based on the elongation and the current roll angle.

28. The elongation monitoring method as described in claim 24, characterized in that, After calculating the surface elongation of the electrode sheet based on the pre-rolling film width, the post-rolling film width, the pre-rolling length, and the post-rolling length, the method further includes: If the elongation does not meet the preset specifications, an alarm command is generated; The rolling process is stopped according to the alarm command, and a prompt message corresponding to the alarm command is generated.

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