Method and system for controlling thickness difference of pole piece

Abstract

The present application belongs to the technical field of lithium battery pole piece production, and particularly relates to a pole piece thickness difference control method and system. The method comprises: obtaining thickness information of the pole piece after the rolling and baking process, wherein the thickness information comprises a real-time thickness value of the pole piece and an average thickness value of the whole film roll where the pole piece is located; performing at least one of marking processing on the pole piece and grading processing on the film roll; the marking processing comprises: identifying a thickness abnormal section in the pole piece based on the deviation of the real-time thickness value from a reference thickness, and marking an abnormal mark at the starting position and the ending position of the thickness abnormal section respectively, wherein the abnormal mark is used for positioning and removing the thickness abnormal section in the die-cutting process; the grading processing comprises: determining a thickness grade of the film roll based on the difference between the average thickness value of the whole film roll and a standard average thickness value, and writing the thickness grade into a delivery mark of the film roll, wherein the thickness grade is used for machine matching in the winding process.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery electrode production technology, specifically relating to a method and system for controlling electrode thickness differences. Background Technology

[0002] In the manufacturing process of lithium battery electrodes, the consistency of electrode thickness has a significant impact on the yield and efficiency of subsequent winding processes. In existing technologies, electrode thickness is typically controlled through a roll forming and baking process, with an overall thickness tolerance range (e.g., ±1.5μm) set as the acceptance criterion. However, two prominent problems exist in actual production: First, there are localized areas of abnormal thickness within the same roll of electrode sheets. Affected by oven temperature fluctuations and changes in roller speed (especially during equipment start-up and shutdown), the thickness difference between the electrode sheet in the start-up / shutdown section and the stable main body area within the same roll can reach 2-3 μm. Existing thickness measurement systems only determine the thickness of the entire roll or fixed points, and cannot identify and locate these localized areas of abnormal thickness. Once these abnormal sections are transferred to the winding process, sudden thickness changes can lead to electrode tab misalignment defects, with a defect rate of approximately 1.4%. This also forces operators to frequently peel and re-attach TFL layers from the winding needles, severely impacting intermediate production efficiency.

[0003] Secondly, there is a lack of refined management of thickness differences between different rolls. Even if the thickness of each roll of electrode sheet is within the standard range (e.g., ±1.5μm), there are still batch-to-batch thickness fluctuations (affected by factors such as the surface density of the incoming coating). Existing technology typically only determines "qualified" or "unqualified," without further categorizing thickness differences within the qualified range. When changing between different rolls in the winding process, the inconsistent thickness necessitates repeated adjustments to the winding needle parameters, making rapid and stable machine matching impossible, which also affects production efficiency and yield.

[0004] Therefore, how to solve the problem of eliminating local thickness abnormalities within the same roll and adapting to thickness differences between different rolls without increasing the complexity of equipment is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a method and system for controlling electrode thickness differences, which aims to improve electrode thickness consistency, reduce excessive scrap, and improve winding production efficiency.

[0006] A first aspect of this invention provides a method for controlling electrode thickness variation, the method comprising: Obtain the thickness information of the electrode sheet after the roll baking process. The thickness information includes the real-time thickness value of the electrode sheet and the average thickness of the entire roll of film containing the electrode sheet. Perform at least one of marking processing on the electrode sheet and sorting processing on the film roll; The marking process includes: based on the deviation between the real-time thickness value and the reference thickness, identifying the thickness abnormal segment in the electrode sheet, and marking abnormal marks at the start and end positions of the thickness abnormal segment respectively. The abnormal marks are used for the die-cutting process to locate and remove the thickness abnormal segment. The grading process includes: determining the thickness grade of the film roll based on a preset range where the difference between the average thickness of the whole roll and the average thickness of the standard roll lies, and writing the thickness grade into the shipment identifier of the film roll. The thickness grade is used for machine matching in the winding process.

[0007] Preferably, identifying thickness anomaly segments in the electrode based on the deviation between the real-time thickness value and the reference thickness includes: The cumulative average thickness of the electrode sheets produced under normal conditions is used as the reference thickness. The difference between the reference thickness and the real-time thickness value is calculated to obtain the thickness deviation. ; when When the thickness of the electrode at the current thickness measurement position is determined to be normal; when When the thickness of the electrode at the current thickness measurement position is determined to be abnormal, then... The preset thickness deviation threshold is used; A segment of electrode in which the thickness of several consecutive thickness measurement positions is abnormal is identified as the thickness abnormal segment.

[0008] Preferably, the step of marking the abnormality at the beginning and end positions of the thickness anomaly segment includes: Obtain the fixed spacing between the thickness measurement position and the marking position along the electrode strip direction. and the belt travel speed of the electrode. ; The ratio of the fixed spacing to the conveyor speed is used as the marking delay time. The marking delay time is used to compensate for the time it takes for the thickness abnormal segment to travel from the thickness measurement position to the marking position; From the moment the starting position of the thickness anomaly segment is detected, after the marking delay period, the marking action is triggered to mark the anomaly at the starting position; From the moment the termination position of the thickness abnormal segment is detected, the marking action is triggered after the marking delay time, and the abnormal mark is marked at the termination position.

[0009] Preferably, the thickness anomaly segment includes an electrode segment generated during the start-up and shutdown process of the rolling equipment; identifying the thickness anomaly segment in the electrode sheet further includes: Obtain the belt travel length segment of the electrode sheet before and after the start / stop button of the roller pressing equipment is triggered; The tape length segment is compared and verified with the thickness anomaly segment identified based on the real-time thickness value, and the segment that matches the verification is retained as the thickness anomaly segment.

[0010] Preferably, determining the thickness level of the film roll based on the preset range of the difference between the average thickness of the entire roll and the average thickness of the standard roll includes: Calculate the difference between the average thickness of the entire roll and the average thickness of the standard roll. ; Based on the difference The preset range into which the film roll falls divides it into one of the following three thickness levels: First level: The aforementioned difference satisfy ; Second level: The difference satisfy ; Third level: The difference satisfy ; in, This is the preset gear limit value. The preset gear segmentation value, and .

[0011] Preferably, the thickness setting is used for machine matching in the winding process, including: A pre-established correspondence is made between multiple winding machines in the winding process and the thickness levels, with each winding machine corresponding to at least one of the thickness levels; When the film roll enters the winding process, the thickness level in the shipping label of the film roll is read; The film roll is assigned to the winding device corresponding to the thickness level read and wound.

[0012] Preferably, the anomaly marker is used in the die-cutting process to locate and remove the thickness-abnormal segments, including: After the film roll is transferred to the die-cutting process, the abnormal marking is detected on the unwinding section of the film roll by a marking sensor; In response to the marking sensor detecting the abnormal marking located at the starting position, a stop signal is triggered to stop the die-cutting process; In response to the abnormal marker located at the termination position being positioned at the rejection station, the thickness abnormal segment between the abnormal marker located at the start position and the abnormal marker located at the termination position is rejected.

[0013] A second aspect of the present invention provides an electrode thickness difference control system, the system comprising a thickness measuring device, a control device, and at least one of a marking device and a gear management device, wherein: A thickness measuring device is installed after the rolling and baking process to collect the real-time thickness value of the electrode sheet and the average thickness of the entire roll of film containing the electrode sheet. A marking device is arranged downstream of the thickness measuring device along the electrode travel direction, and is used to mark abnormality on the electrode in response to a thickness abnormality signal. A thickness management device for writing the thickness grade result on the shipment label of the film roll in response to the thickness grade result of the film roll; A control device is communicatively connected to the thickness measuring device, the marking device, and the gear management device. The control device is configured to execute at least one of a marking control process and a gear control process. The marking control process includes: identifying thickness abnormal segments in the electrode sheet based on the deviation between the real-time thickness value and the reference thickness, and sending the thickness abnormality signal to the marking device so that the marking device marks the abnormality mark at the start and end positions of the thickness abnormal segment respectively; the abnormality mark is used for the die-cutting process to locate and remove the thickness abnormal segment. The grading control process includes: determining the thickness grade of the film roll based on the preset range of the difference between the average thickness of the whole roll and the average thickness of the standard roll, and sending the thickness grade result to the grade management device; the thickness grade is used for machine matching in the winding process.

[0014] Preferably, the marking device includes a first marking machine and a second marking machine arranged at intervals along the electrode travel direction. The first marking machine and the thickness measuring device maintain a first fixed distance D1 along the travel direction, and the second marking machine and the thickness measuring device maintain a second fixed distance D2 along the travel direction, where D2 > D1. The control device is further configured to: An abnormal starting position mark is set at the first marking machine with a marking delay time T1 = D1 / V, and an abnormal ending position mark is set at the second marking machine with a marking delay time T2 = D2 / V. From the moment the starting position of the thickness abnormal segment is detected, after the marking delay time T1, the first marking machine is controlled to trigger the marking action to mark the abnormal mark at the starting position; Upon detection of the termination position of the thickness anomaly segment, after a marking delay time T2, the second marking machine is controlled to trigger a marking action, affixing the anomaly mark at the termination position. Preferably, the gear management device includes a manufacturing execution system; the manufacturing execution system is configured as follows: Receive the average thickness of the entire roll uploaded by the thickness measuring device, and calculate the difference between the average thickness of the entire roll and the average thickness of the standard roll. ; Based on the difference The preset range into which the film roll falls determines the corresponding thickness range. The thickness level is automatically written into the shipment identifier of the film roll, so that the winding process can read the shipment identifier and allocate the film roll to the winding equipment corresponding to the thickness level.

[0015] The beneficial effects of this invention include: ① By identifying the deviation between the real-time thickness and the reference thickness in the electrode sheet, the start and end positions of the abnormal thickness segments are accurately located and marked, so that these abnormal segments can be accurately removed in the die-cutting process and prevented from flowing into the winding process. ② By calculating the difference between the average thickness of the whole roll and the standard average, the difference is automatically divided into multiple grades and written into the shipment label; the winding process can select the appropriate grade of film roll according to the process requirements of different machines, so as to avoid frequent machine adjustments caused by thickness fluctuations between different rolls (although within the standard range).

[0016] ③ The marking process is automatically completed in coordination based on a fixed distance and belt speed. The grading process is automatically determined and marked based on the thickness difference, eliminating the need for manual judgment of whether the thickness is abnormal or which grade it belongs to, significantly reducing human error and omission. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating a method for controlling electrode thickness differences according to an embodiment of the present invention; Figure 2 This is a structural block diagram of an electrode thickness difference control system according to an embodiment of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct contact between components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. The various technical features in this invention can be combined interactively without contradicting each other.

[0021] like Figure 1 As shown, an embodiment of the present invention provides a method for controlling electrode thickness differences, comprising: S1. Obtain the thickness information of the electrode after the rolling and baking process. The thickness information includes the real-time thickness value of the electrode and the average thickness of the entire roll of film containing the electrode.

[0022] The real-time thickness value is collected by a thickness gauge set after the rolling and baking process, which collects the thickness data of each measurement point at a fixed sampling frequency; the average thickness of the whole roll refers to the arithmetic mean of the thickness data of all measurement points of the entire film roll from the beginning to the end.

[0023] The purpose of obtaining this information is to provide basic data support for subsequent thickness anomaly identification and overall roll quality classification. During the roll forming and baking process, equipment start-up and shutdown or temperature fluctuations can cause local anomalies in electrode thickness. Furthermore, differences in coating surface density between different film rolls can also cause overall thickness deviations. Therefore, it is necessary to collect local real-time data and overall statistical data separately for layered management.

[0024] S2. Perform at least one of the following: marking the electrode sheet and sorting the film roll.

[0025] The marking process addresses the thickness differences between different areas within the same film roll by physically marking out sections with abnormal thickness for removal in subsequent processes. The grading process addresses the overall thickness differences between different film rolls by classifying them using grade markings to ensure proper machine matching for the winding process.

[0026] These two processing methods can be implemented individually or simultaneously, depending on the control requirements of the production site. If the consistency of thickness within the same roll is the primary concern, marking should be prioritized; if thickness fluctuations between different rolls have a greater impact, grading should be prioritized. In the optimal solution, both processing methods are used simultaneously to achieve comprehensive control.

[0027] The marking process includes: S201, based on the deviation between the real-time thickness value and the reference thickness, identifying the thickness abnormality segment in the electrode sheet, and marking abnormality marks at the start and end positions of the thickness abnormality segment respectively. The abnormality marks are used for the positioning and removal of the thickness abnormality segment in the die-cutting process. The reference thickness is typically the cumulative average of electrode thicknesses under normal, stable production conditions. This value represents the thickness level expected by the process standard. The deviation between the real-time thickness value and the reference thickness reflects the thickness fluctuation at the current measurement point. When the deviation exceeds a preset threshold, it is considered an abnormal thickness. Areas where multiple consecutive measurement points are identified as abnormal constitute an abnormal thickness segment. After identifying the abnormal thickness segment, anomaly markers are placed at the start and end positions of this segment. The purpose of these anomaly markers is to provide precise positioning information for the die-cutting process. When the marking sensor in the die-cutting process detects an anomaly marker at the start position, it triggers a stop. Then, an employee or automated mechanism manually pulls out and removes the electrode segment between the start and end markers, ensuring that the abnormal thickness segment does not flow into the winding process.

[0028] The grading process includes: S202, determining the thickness grade of the film roll based on the preset range of the difference between the average thickness of the whole roll and the average thickness of the standard roll, and writing the thickness grade into the shipment identifier of the film roll. The thickness grade is used for machine matching in the winding process.

[0029] The average thickness of the entire roll reflects the overall thickness level of the film roll, while the standard average thickness is the ideal thickness value designed for the process. The difference between the two quantifies the overall deviation direction and magnitude of the film roll relative to the standard value. The preset interval discretizes continuous thickness deviation values ​​into several levels, each level corresponding to a deviation range. After determining the thickness level, this level information is written into the film roll's shipping identifier, which can be a paper shipping tag or an electronic tag. The thickness level is used for machine matching in the winding process; that is, film rolls with different levels are assigned to winding equipment suitable for that level, thereby avoiding electrode misalignment defects caused by mismatch between the incoming material thickness and the winding machine's process window.

[0030] Specifically, on the lithium battery negative electrode production line, after the rolling and baking process, the electrode sheets continuously move into the thickness measurement area. The thickness gauge collects the real-time thickness value of each measurement point several times per second and simultaneously calculates the average thickness of the entire roll from the beginning to the current position. The control device calculates the difference between the reference thickness and the real-time thickness value in real time. When the absolute value of the difference reaches 1.5 μm or more, the measurement point is determined to be an abnormal point. Areas with consecutive abnormal points are identified as thickness abnormal sections. These abnormal sections usually correspond to electrode segments caused by speed changes and oven temperature drops during the start-up and shutdown of the rolling equipment, and are approximately several meters in length. The control device calculates the marking delay time T = D / V based on the fixed distance D between the thickness gauge and the marking machine and the electrode sheet conveyor speed V. When the thickness gauge detects the starting position of the thickness abnormal section, the timing begins. After T seconds, the marking machine marks a yellow abnormal mark on the edge of the electrode sheet; similarly, when the ending position is detected, a second yellow abnormal mark is marked after another T seconds. Simultaneously, the control device calculates the difference between the average thickness of the entire roll and the average thickness of the standard roll. Assuming the average standard thickness is 100µm and the average thickness of the entire roll is 101.2µm, the difference is 1.2µm. This difference falls within the preset range of 0.5µm to 1.5µm, therefore the thickness grade of the film roll is determined to be the third grade. This grade information is automatically written into the QR code on the shipping label via the MES (Manufacturing Execution System). When the film roll flows to the winding process, the operator scans the QR code to obtain the grade information and assigns the film roll to a winding machine suitable for the third thickness range for production.

[0031] The reference thickness for identifying abnormal thickness sections can be the cumulative average thickness of electrode sheets in normal production sections, or it can be the process design value or the statistical value of the thickness of several recent normal film rolls. When marking abnormalities, a contact marking machine can be used to coat the electrode edge with color markings, or a non-contact inkjet marking machine or laser marking machine can be used to form identifiable optical markings.

[0032] This embodiment addresses two independent issues—thickness differences within the same roll and thickness differences between different rolls—through a dual-track mechanism of marking and grading. Marking enables precise location and removal of abnormal sections, avoiding the waste of scrapping entire rolls; grading provides refined classification and management of film rolls, offering a quantitative basis for machine matching in the winding process. Both methods can operate independently or collaboratively, exhibiting strong production adaptability. Actual test data shows that this solution can reduce the winding tab misalignment defect rate from 1.4% to approximately 0.2%, significantly improving production yield and efficiency.

[0033] In some embodiments, based on the deviation between the real-time thickness value and the reference thickness, identifying thickness anomaly segments in the electrode sheet includes: The cumulative average thickness of the electrode sheets produced under normal conditions is used as the baseline thickness.

[0034] Among them, the electrode sheet produced under normal production conditions refers to the electrode sheet produced under stable operation of the rolling equipment. During this stage, the equipment parameters are constant, the belt speed is stable, and the oven temperature is uniform, so the electrode sheet thickness fluctuates less; the cumulative average value refers to the value obtained by arithmetically averaging the thickness values ​​of all measurement points in the normal production section.

[0035] The purpose of using the cumulative average as the baseline thickness is to establish a dynamically updated reference standard that reflects the actual thickness level under current process conditions, which is more scientific and reasonable than a fixed threshold. When process parameters are adjusted, the cumulative average will automatically change accordingly, without requiring manual intervention to modify the baseline value.

[0036] The thickness deviation is obtained by calculating the difference between the reference thickness and the real-time thickness value. ; when At that time, the thickness of the electrode at the current thickness measurement position is determined to be normal; when When this occurs, the thickness of the electrode at the current thickness measurement position is determined to be abnormal; among which, The preset thickness deviation threshold is used; An electrode segment in which the thickness status of several consecutive thickness measurement positions is abnormal is identified as a thickness abnormal segment.

[0037] Specifically, under normal production conditions, the thickness gauge continuously collects thickness data, and the control device calculates the cumulative average value of the normal production section in real time as the baseline thickness. Assuming the current cumulative average value is 100µm, and the ΔX threshold is set to 1.5µm, the thickness gauge collects a real-time thickness value of 98.7µm at the 1001st measurement point. Therefore, ΔX = 100 - 98.7 = 1.3µm. Since the absolute value of 1.3µm is less than 1.5µm, this point is considered normal. At the 1002nd measurement point, a value of 97.5µm is collected, with ΔX = 2.5µm. Since the absolute value is greater than 1.5µm, this point is considered abnormal. Subsequently, the real-time thickness values ​​at measurement points 1003 to 1050 fluctuate between 96.5µm and 98.0µm, with the absolute value of ΔX at each point greater than 1.5µm. These points are continuously considered abnormal. At the 1051st measurement point, the thickness value returns to 99.2µm, and the absolute value of ΔX is 0.8µm, which is less than 1.5µm, returning to normal. The electrode segments corresponding to the 1002nd to 1050th measurement points were identified as thickness abnormality segments. The length of the electrode strip in this segment was approximately several meters, corresponding to the unstable area during the start-up and shutdown process of the rolling mill.

[0038] When calculating the thickness deviation, either the reference thickness minus the real-time thickness value or the real-time thickness value minus the reference thickness can be used. The signs are opposite, but the absolute values ​​are the same. The same function can be achieved simply by adjusting the judgment logic accordingly. When determining the thickness status, either an absolute threshold or a relative threshold can be used, such as comparing the percentage of the deviation to the reference thickness with a preset percentage threshold. This method maintains relatively stable sensitivity even when the reference thickness changes significantly due to process adjustments.

[0039] This embodiment achieves accurate identification of thickness anomaly segments through two core mechanisms: a dynamic benchmark based on cumulative averages and a continuous anomaly determination mechanism. The cumulative average benchmark eliminates static deviations between different batches and different equipment, ensuring that the anomaly determination standard is always adapted to the current production status. The continuous determination mechanism avoids false triggering caused by single-point noise interference, guaranteeing the reliability of the marking action. These two mechanisms work together to significantly improve the accuracy of thickness anomaly segment identification, ensuring that genuine anomaly areas are not missed and that excessive scrapping is not caused by misjudgment.

[0040] In some embodiments, abnormal markers are affixed at the start and end positions of the thickness abnormality segment, including: Obtain the fixed spacing between the thickness measurement position and the marking position along the electrode strip direction. and the belt travel speed of the electrode. ; In this context, the thickness measurement position is the spatial location of the thickness gauge sensor, and the marking position is the spatial location of the marking machine nozzle or marking head. Due to physical space limitations, these two positions typically do not coincide; the thickness gauge is located upstream, and the marking machine is located downstream, with a certain distance D between them. The electrode moves continuously at a belt speed V. Therefore, when the thickness gauge detects a boundary point of an abnormal thickness segment, that boundary point does not immediately reach the bottom of the marking machine but requires a certain period of time to move to the marking position. Obtaining D and V is for calculating this transmission time to achieve accurate delayed marking.

[0041] The ratio of the fixed spacing to the conveyor speed is used as the marking delay time. The marking delay time is used to compensate for the time it takes for the tape to travel from the thickness measurement position to the marking position in sections with abnormal thickness. From the moment the starting position of the thickness anomaly segment is identified, the marking action is triggered after a marking delay of T1, and the anomaly mark is set at the starting position; The moment the starting position is identified refers to the instant when the thickness gauge detects the first abnormal point and determines that point as the starting point of a continuous abnormal segment. At this moment, the control device does not immediately send a trigger signal to the marking machine, but instead starts a timer to wait for T1 seconds. After T1 seconds, the starting position has just moved below the first marking machine, at which point the trigger signal is sent and the marking machine affixes an abnormal mark at that position. This delayed triggering mechanism ensures that the marked position highly coincides with the actual abnormal boundary.

[0042] When the termination position of the thickness abnormality segment is detected, the marking action is triggered after a marking delay time T2, and the abnormality mark is set at the termination position.

[0043] The identification time of the termination position refers to the moment when the last abnormal point is detected before the first normal point after the end of the continuous abnormal segment. After waiting for T2 seconds, a second abnormal mark is placed at this position. The area between the start mark and the termination mark is the complete thickness abnormal segment, and the die-cutting process only needs to remove the electrode sheet between these two marks.

[0044] Specifically, on the production line, the fixed distance D1 between the thickness gauge and the first marking machine is 3m, and the fixed distance D2 between the thickness gauge and the second marking machine is 5m. The electrode conveyor speed V is 0.5m / s, so the marking delay time T1 = 3 / 0.5 = 6 seconds. When the control device detects the starting position of the thickness abnormality segment, a 6-second timer is started. After 6 seconds, the starting position moves precisely below the marking machine, and the control device sends a trigger pulse to the marking machine, which marks a yellow rectangular mark on the edge of the electrode. Subsequently, when the control device detects the ending position of the thickness abnormality segment, the marking delay time T2 = 5 / 0.5 = 10 seconds, and then a 10-second timer is started. After 10 seconds, the ending position moves below the second marking machine, and the control device triggers the second marking machine to mark a second yellow rectangular mark at the ending position. The length of the electrode segment between the starting and ending marks is the length of the entire abnormal segment, usually several meters. These two marks are identified and read by the marking sensor in the subsequent die-cutting process.

[0045] When obtaining the fixed spacing D, the factory-calibrated mechanical installation distance can be used, or the actual distance after on-site measurement and calibration can be used, because there may be slight positional deviations after the marking machine is installed, which need to be corrected through calibration measurement. When triggering the marking action, the control device can actively send a trigger signal, or a distributed control method can be used where the marking machine continuously listens to the thickness gauge signal and times itself. This method reduces the burden on the central controller, but has higher requirements for timing synchronization.

[0046] This embodiment solves the positioning error problem caused by the spatial separation between the thickness measurement position and the marking position by using a delayed marking mechanism. Without delay compensation, the anomaly mark would be marked at a distance D behind the actual position of the anomaly segment, causing a misalignment between the area between the start and end marks and the actual anomaly segment, resulting in either incomplete removal or mistaken removal of normal electrodes. After adopting delayed marking, the mark position is precisely aligned with the actual anomaly boundary, ensuring the accuracy of the removal operation and minimizing the scrap volume.

[0047] In some embodiments, the thickness aberration segment includes an electrode segment generated during the start-up and shutdown of the rolling mill; identifying the thickness aberration segment in the electrode sheet further includes: Obtain the belt travel length segment of the electrode sheets before and after the start / stop button of the roller pressing equipment is triggered; The conveyor belt speed of the roller pressing equipment changes significantly during startup and shutdown, accelerating from a standstill to the set speed or decelerating from the set speed back to a standstill; this speed is unstable. Simultaneously, the oven temperature also fluctuates due to equipment startup and shutdown, as the oven's thermal inertia prevents the temperature from instantly reaching a stable value. The combined effect of speed changes and temperature fluctuations leads to a significant difference in electrode thickness between this section and the stable production section. The system records the moment the operator presses the start or stop button, and also records the current cumulative conveyor belt length of the electrode. By comparing the conveyor belt length at the moment the button is triggered with the conveyor belt length after a certain period, the corresponding electrode length segment during the startup and shutdown process can be calculated.

[0048] The tape length segment is compared and verified with the thickness anomaly segment identified based on the real-time thickness value. The segments that match the verification are retained as thickness anomaly segments.

[0049] The method of identifying thickness anomalies based on real-time thickness values ​​is achieved through thickness deviation determination. However, this method may be affected by measurement noise from the thickness gauge or the surface condition of the electrode in some cases, leading to false positives or false negatives. Comparing the tape travel length segment during the start-stop process as independent prior information with the thickness measurement identification result can serve as cross-validation. If the anomaly segment identified by the thickness measurement closely matches the length segment corresponding to the start-stop process, the identification result is reliable. If they are inconsistent, verification or adjustment of the identification parameters is required.

[0050] Consistent verification means that the start and end positions of the abnormal segments identified by thickness measurement basically coincide with the length segments corresponding to the start and stop processes, or the proportion of the overlapping portion to their respective total lengths exceeds a preset threshold. For segments with consistent verification, they are ultimately confirmed as thickness abnormal segments, and subsequent labeling and removal operations are performed on these confirmed segments. Areas with inconsistent verification are either not marked or marked as pending review, and are judged manually or through further analysis.

[0051] Specifically, at 10:30:15 AM, the operator pressed the start button on the roller pressing equipment, at which point the system recorded a cumulative belt travel length of 1234.5 meters. After an acceleration process, the equipment reached a stable belt travel speed at 10:30:45 AM, at which point the cumulative belt travel length was 1239.5 meters. Therefore, the belt travel length segment corresponding to the start-up process was from 1234.5 meters to 1239.5 meters, a length of 5 meters. Simultaneously, the control device, based on real-time thickness values, identified a thickness anomaly segment between 1234.8 meters and 1239.3 meters, with a thickness deviation consistently exceeding 1.5 μm. Comparing these two segments, the start / stop zone was 1234.5 to 1239.5 meters, and the anomaly segment was identified as 1234.8 to 1239.3 meters. The two segments highly overlapped, with an overlap length of 4.5 meters, accounting for over 90% of the total anomaly segment length, confirming consistency. Therefore, this anomaly segment was retained as the final thickness anomaly segment and marked. If the two do not overlap at all, it indicates that the thickness measurement recognition may be interfered with and the calibration status of the thickness gauge needs to be rechecked.

[0052] When obtaining the conveyor belt length segment before and after the start / stop button is triggered, the length difference displayed on the operation interface can be read manually. Alternatively, the start / stop event timestamps recorded by the control system and the pulse count value of the conveyor belt encoder can be used for automatic calculation. The automatic method avoids the errors and delays of manual reading. When comparing and verifying two segments, the overlap length ratio can be used as a judgment indicator. Alternatively, the absolute value of the difference between the boundary positions of the two segments can be compared with a preset tolerance. The latter method is more intuitive and easier to set up automated judgment rules.

[0053] This embodiment utilizes the physical law that thickness anomalies inevitably occur during the start-up and shutdown process as prior knowledge to cross-verify the thickness measurement identification results. This dual verification mechanism significantly improves the reliability of thickness anomaly segment identification and avoids misjudgments caused by occasional thickness gauge malfunctions or interference from foreign objects on the electrode surface. Simultaneously, this mechanism also provides a reference for the thickness gauge's self-calibration; when the thickness measurement identification results consistently deviate significantly from the start-up and shutdown sections, it can promptly indicate the need for equipment maintenance.

[0054] In some embodiments, determining the thickness level of the film roll based on a preset range in which the difference between the average thickness of the entire roll and the average thickness of the standard roll falls includes: Calculate the difference between the average thickness of the entire roll and the average thickness of the standard roll. ; Based on the difference The preset range into which the film roll falls will divide it into one of the following three thickness levels: First level: Difference satisfy ; Second tier: Difference satisfy ; Third level: Difference satisfy ; in, This is the preset gear limit value. The preset gear segmentation value, and .

[0055] The boundary values ​​for the three gear positions need to be determined in conjunction with the process windows of each machine in the winding process. ΔY1 is the half-width of the center gear position, i.e., the second gear, and is usually set to 0.5µm. This means that film rolls with a deviation within ±0.5µm are considered standard film rolls and assigned to the most common machine. The maximum value of ΔY is usually set to 1.5µm, meaning that film rolls with a deviation exceeding 1.5µm are outside the range of gear control and require separate handling or rework. The setting of the gear position division values ​​needs to consider both the sensitivity of the winding machine to the electrode thickness and the actual control capability of the rolling process.

[0056] Specifically, assuming the standard average thickness is 100µm, ΔY1 is set to 0.5µm, and the maximum value of ΔY is set to 1.5µm. After the thickness gauge completes the thickness acquisition of the entire film roll, the calculated average thickness of the entire roll is 101.2µm. Therefore, ΔY = 101.2 - 100 = 1.2µm. Since 1.2µm is greater than 0.5µm but less than 1.5µm, this film roll is classified as the third grade, i.e., the thicker grade. If the average thickness of another film roll is 99.3µm, ΔY = -0.7µm. Since -0.7µm is less than -0.5µm but greater than -1.5µm, this film roll is classified as the first grade, i.e., the thinner grade. If the average thickness of a third film roll is 100.3µm, ΔY = 0.3µm. Since the absolute value of 0.3µm is less than 0.5µm, this film roll is classified as the second grade, i.e., the standard grade.

[0057] When dividing thickness into grades, a three-grade scheme or a five-grade or more scheme can be adopted. More grades result in finer resolution of the film rolls, but the complexity of machine matching also increases accordingly. It is necessary to choose a balance based on production scale and management capabilities. The preset grade division value ΔY1 can be a fixed value of 0.5um, or a dynamically adjusted value can be used. For example, it can be automatically calculated based on the standard deviation of the average thickness of all recently produced film rolls to ensure that the number of film rolls in each grade is roughly balanced to avoid some grades being oversaturated and others being idle.

[0058] This embodiment simplifies and simplifies film roll management by discretizing the continuously varying thickness deviation into a finite number of levels. The three levels cover three typical cases: thinner, standard, and thicker, satisfying the winding process's need for incoming material thickness classification without adding excessive management complexity. The quantitative definition of the level boundaries is clear and unambiguous, allowing for automatic determination and identification by the MES system, eliminating the subjectivity and uncertainty of manual judgment.

[0059] In some embodiments, the thickness setting is used for machine matching in the winding process, including: A pre-established correspondence between multiple winding machines in the winding process and thickness levels is established, with each winding machine corresponding to at least one thickness level. Different models or types of winding equipment have varying adaptability to electrode thickness. Some equipment has a wider tolerance for thickness and can accommodate electrode thicknesses of multiple grades. Other equipment is more sensitive to thickness and is only suitable for producing electrode thicknesses of specific grades. By establishing a pre-defined correspondence, appropriate film rolls can be assigned to suitable equipment based on the specific machine requirements. The establishment of this correspondence is based on a correlation analysis of the electrode tab misalignment defect rate and the incoming material thickness grade for each machine in historical production data.

[0060] When the film roll enters the winding process, read the thickness level in the film roll's shipping label.

[0061] When the film roll enters the winding process, the thickness level in the shipping label is read. The shipping label can be a barcode or QR code on a paper shipping tag, or an RFID electronic tag affixed to the film roll. The operator uses a barcode scanner to scan the barcode or an RFID reader to read the data in the electronic tag. The reading process can be triggered manually or automatically. After obtaining the thickness level information, the system can determine whether the current film roll belongs to the thinner or thicker category.

[0062] The film roll is assigned to a winding device corresponding to the thickness setting read for winding.

[0063] The allocation decision can be executed automatically by the MES system, or it can be made by the system providing recommendations which are then confirmed and executed by the operator. The allocation principle is to assign thinner membrane rolls to equipment well-suited to thinner electrodes, thicker membrane rolls to equipment well-suited to thicker electrodes, and standard membrane rolls can be assigned to any equipment or preferentially to equipment with lighter loads. Through this targeted allocation, each piece of equipment operates within its optimal incoming material thickness range, significantly reducing the electrode misalignment defect rate.

[0064] Specifically, the winding process involves five winding machines, numbered W01 to W05. Based on historical data analysis, machines W01 and W02 perform best with thinner electrodes, so the first grade, i.e., the thinner grade, is assigned to W01 and W02; W03 and W04 perform stably with standard thickness electrodes, so the second grade is assigned to W03 and W04; W05 is the most adaptable to thicker electrodes, so the third grade is assigned to W05.

[0065] When a film roll arrives at the winding process, the operator scans the QR code on its shipping tag, and the system reads that the thickness level is the first level. The MES system automatically recommends assigning the film roll to either W01 or W02, and the operator loads the film roll onto the W01 machine for winding production according to the recommendation. When a thickness level corresponds to multiple machines, the system can further perform load balancing based on the current workload and expected idle time of each machine.

[0066] When establishing the correspondence between thickness levels and winding equipment, a static matching table based on historical defect rate statistics can be used, or a dynamic matching algorithm based on machine learning can be employed. This algorithm analyzes the latest production data of each machine in real time and dynamically adjusts the matching rules to adapt to changes in equipment status. When reading the thickness level in the shipping label, a manual handheld barcode scanner can be used, or a fixed barcode reader on the conveyor line can be used for automatic reading. Automated reading reduces manual operation and improves production cycle time.

[0067] This embodiment forms a closed-loop control by organically combining the grading results with production scheduling. Grading itself does not directly generate value; its value is realized only when the grading information is actually used to guide production allocation. By pre-establishing the correspondence between machine positions and grading levels and allocating film rolls according to this correspondence, optimal matching between incoming material characteristics and processing equipment is achieved, fundamentally solving the problem of electrode misalignment caused by differences in roll thickness. Actual measurement data shows that after implementing this solution, the defect rate of winding electrode misalignment decreased from 1.4% to approximately 0.2%.

[0068] In some embodiments, the anomaly marker is used in the die-cutting process to locate and remove segments with abnormal thickness, including: After the film roll is transferred to the die-cutting process, the unwinding section of the film roll is detected by marking sensors to mark any abnormalities. In response to the marking sensor detecting an abnormal mark at the starting position, a stop signal is triggered to stop the die-cutting process; In response to the abnormal marker located at the termination position being positioned at the rejection station, the thickness abnormal segment between the abnormal marker located at the start position and the abnormal marker located at the termination position is rejected.

[0069] Specifically, a photoelectric sensor is installed in the unwinding section of the die-cutting process. This sensor can identify the yellow markings on the edge of the electrode sheet. When the initial yellow marking set in the rolling process passes below the sensor, the sensor outputs a high-level signal. Upon receiving this signal, the programmable controller of the die-cutting machine immediately executes the stop procedure, controlling the unwinding motor to stop rotating and the die-cutting punch to stop moving. At this time, the initial yellow marking stops about 10 centimeters downstream of the sensor position. After seeing the stop prompt, the operator manually pulls out the electrode sheet until the termination yellow marking is pulled to the waste chute entrance of the rejection station. The electrode sheet segment with a length of approximately 5 meters between the initial and termination markings is completely exposed above the waste chute. The operator uses scissors to cut the electrode sheet behind the initial and termination markings respectively, and the cut electrode segments fall into the waste chute. Then, the ends of the two cut electrode sheets are rejoined or inserted into the subsequent guide rollers, and the start button is pressed to resume die-cutting production.

[0070] When detecting abnormal markings, photoelectric sensors can be used to detect changes in the reflectivity of color blocks, and vision cameras can be used for image recognition. Vision cameras can not only detect the presence of markings but also confirm their integrity and positional accuracy, making them suitable for applications requiring higher positioning accuracy. When removing sections with abnormal thickness, manual pulling and cutting can be used, or an automatic removal mechanism can be employed. This mechanism includes clamping rollers and a cutter, which automatically clamps the electrode sheet and performs cutting and waste removal actions when the termination marking is detected to have reached the designated position, completely replacing manual operation.

[0071] This embodiment seamlessly integrates the marking process with the rejection operation in the die-cutting process, forming a complete abnormal segment isolation mechanism. The introduction of the marking sensor enables automatic detection and automatic shutdown, eliminating the need for manual visual inspection of abnormal segments. The dual-marking design with start and end marks ensures precise and controllable rejection range, preventing both missed abnormal segments and accidental rejection of normal electrode sheets. Compared to traditional methods of scrapping entire rolls or visual inspection, this precise rejection scheme based on dual marking significantly reduces scrap volume while ensuring reliable rejection results.

[0072] In some embodiments, this embodiment provides an electrode thickness difference control system 30, including a thickness measuring device 301, a control device 304, and at least one of a marking device 302 and a gear management device 303: Thickness measuring device 301 is installed after the rolling and baking process to collect the real-time thickness value of the electrode sheet and the average thickness of the entire roll of film containing the electrode sheet. The marking device 302 is arranged downstream of the thickness measuring device along the electrode travel direction and is used to mark abnormality on the electrode in response to an abnormal thickness signal. The thickness management device 303 is used to write the thickness grade on the film roll's shipping label in response to the thickness grade result of the film roll; The control device 304 is communicatively connected to the thickness measuring device, the marking device, and the gear management device. The control device is configured to execute at least one of the marking control process and the gear control process. The marking control process includes: identifying thickness abnormal segments in the electrode based on the deviation between the real-time thickness value and the reference thickness, and sending a thickness abnormality signal to the marking device so that the marking device marks abnormality marks at the start and end positions of the thickness abnormal segment; the abnormality marks are used for the die-cutting process to locate and remove the thickness abnormal segment. The grading control process includes: determining the thickness grade of the film roll based on the preset range of the difference between the average thickness of the whole roll and the average thickness of the standard roll, and sending the thickness grade result to the grade management device; the thickness grade is used for machine matching in the winding process.

[0073] In some embodiments, the marking apparatus includes a first marking machine and a second marking machine arranged at intervals along the electrode travel direction. The first marking machine and the thickness measuring device maintain a first fixed distance D1 along the travel direction, and the second marking machine and the thickness measuring device maintain a second fixed distance D2 along the travel direction, where D2 > D1. The control device is further configured to: An abnormal starting position mark is set at the first marking machine with a marking delay time T1 = D1 / V, and an abnormal ending position mark is set at the second marking machine with a marking delay time T2 = D2 / V. From the moment the starting position of the thickness abnormal segment is detected, after the marking delay time T1, the first marking machine is controlled to trigger the marking action to mark the abnormal mark at the starting position; From the moment the termination position of the thickness abnormal segment is detected, after the marking delay time T2, the second marking machine is controlled to trigger the marking action to mark the abnormal mark at the termination position.

[0074] In some embodiments, the gear management device includes a manufacturing execution system; the manufacturing execution system is configured to: Receive the average thickness of the entire roll uploaded by the thickness measuring device, and calculate the difference between the average thickness of the entire roll and the average thickness of the standard roll. ; Based on the difference The preset range into which the film roll falls determines the corresponding thickness range; The thickness setting is automatically written into the film roll's shipping identifier, so that the winding process can read the shipping identifier and allocate the film roll to the winding equipment corresponding to the thickness setting.

[0075] It should be noted that the electrode thickness difference control system provided in the above embodiments is only illustrated by the division of the above functional modules when performing electrode thickness difference control. In actual applications, the above functions can be assigned to different functional modules as needed. That is, the internal structure of the electrode thickness difference control device will be divided into different functional modules to complete all or part of the functions described above.

[0076] Furthermore, the embodiments of the electrode thickness difference control system and the electrode thickness difference control method provided in the above embodiments belong to the same concept, and the specific way in which each module performs its operation has been described in detail in the method embodiments, and will not be repeated here.

[0077] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A method for controlling electrode thickness variation, characterized in that, The method includes: Obtain the thickness information of the electrode sheet after the rolling and baking process. The thickness information includes the real-time thickness value of the electrode sheet and the average thickness of the entire roll of film containing the electrode sheet. Perform at least one of marking processing on the electrode sheet and sorting processing on the film roll; The marking process includes: based on the deviation between the real-time thickness value and the reference thickness, identifying the thickness abnormal segment in the electrode sheet, and marking abnormal marks at the start and end positions of the thickness abnormal segment respectively. The abnormal marks are used for the die-cutting process to locate and remove the thickness abnormal segment. The grading process includes: determining the thickness grade of the film roll based on a preset range where the difference between the average thickness of the whole roll and the average thickness of the standard roll lies, and writing the thickness grade into the shipment identifier of the film roll. The thickness grade is used for machine matching in the winding process.

2. The method for controlling electrode thickness difference according to claim 1, characterized in that, The step of identifying thickness anomaly segments in the electrode based on the deviation between the real-time thickness value and the reference thickness includes: The cumulative average thickness of the electrode sheets produced under normal conditions is used as the reference thickness. The difference between the reference thickness and the real-time thickness value is calculated to obtain the thickness deviation. ; when When the thickness of the electrode at the current thickness measurement position is determined to be normal; when When the thickness of the electrode at the current thickness measurement position is determined to be abnormal, then... The preset thickness deviation threshold is used; A segment of electrode in which the thickness of several consecutive thickness measurement positions is abnormal is identified as the thickness abnormal segment.

3. The method for controlling electrode thickness difference according to claim 1, characterized in that, The step of marking abnormalities at the beginning and end positions of the thickness anomaly segment includes: Obtain the fixed spacing between the thickness measurement position and the marking position along the electrode strip direction. and the belt travel speed of the electrode. ; The ratio of the fixed spacing to the conveyor speed is used as the marking delay time. The marking delay time is used to compensate for the time it takes for the thickness abnormal segment to travel from the thickness measurement position to the marking position; From the moment the starting position of the thickness anomaly segment is detected, a marking action is triggered after the marking delay time, and the anomaly mark is affixed to the starting position. From the moment the termination position of the thickness abnormal segment is detected, the marking action is triggered after the marking delay time, and the abnormal mark is marked at the termination position.

4. The method for controlling electrode thickness difference according to claim 1, characterized in that, The thickness anomaly segment includes electrode segments generated during the start-up and shutdown of the rolling equipment; identifying the thickness anomaly segment in the electrode sheet further includes: Obtain the belt travel length segment of the electrode sheet before and after the start / stop button of the roller pressing equipment is triggered; The tape length segment is compared and verified with the thickness anomaly segment identified based on the real-time thickness value, and the segment that matches the verification is retained as the thickness anomaly segment.

5. The method for controlling electrode thickness difference according to claim 1, characterized in that, Determining the thickness level of the film roll based on the preset range of the difference between the average thickness of the entire roll and the average thickness of the standard roll includes: Calculate the difference between the average thickness of the entire roll and the average thickness of the standard roll. ; Based on the difference The preset range into which the film roll falls divides it into one of the following three thickness levels: First level: The aforementioned difference satisfy ; Second level: The difference satisfy ; Third level: The difference satisfy ; in, This is the preset gear limit value. The preset gear segmentation value, and .

6. The method for controlling electrode thickness difference according to claim 1, characterized in that, The thickness settings are used for machine matching in the winding process, including: A pre-established correspondence is made between multiple winding machines in the winding process and the thickness levels, with each winding machine corresponding to at least one of the thickness levels; When the film roll enters the winding process, the thickness level in the shipping label of the film roll is read; The film roll is assigned to the winding device corresponding to the thickness level read and wound.

7. The method for controlling electrode thickness difference according to claim 1, characterized in that, The anomaly marker is used in the die-cutting process to locate and remove the thickness anomaly segments, including: After the film roll is transferred to the die-cutting process, the abnormal marking is detected on the unwinding section of the film roll by a marking sensor; In response to the marking sensor detecting the abnormal marking located at the starting position, a stop signal is triggered to stop the die-cutting process; In response to the abnormal marker located at the termination position being positioned at the rejection station, the thickness abnormal segment between the abnormal marker located at the start position and the abnormal marker located at the termination position is rejected.

8. A system for controlling electrode thickness differences, characterized in that, The system includes a thickness measuring device, a control device, and at least one of a marking device and a gear management device, wherein: A thickness measuring device is installed after the rolling and baking process to collect the real-time thickness value of the electrode sheet and the average thickness of the entire roll of film containing the electrode sheet. A marking device is arranged downstream of the thickness measuring device along the electrode travel direction, and is used to mark abnormality on the electrode in response to a thickness abnormality signal. A thickness management device for writing the thickness grade result on the shipment label of the film roll in response to the thickness grade result of the film roll; A control device is communicatively connected to the thickness measuring device, the marking device, and the gear management device. The control device is configured to execute at least one of a marking control process and a gear control process. The marking control process includes: identifying thickness abnormal segments in the electrode sheet based on the deviation between the real-time thickness value and the reference thickness, and sending the thickness abnormality signal to the marking device so that the marking device marks the abnormality mark at the start and end positions of the thickness abnormal segment respectively; the abnormality mark is used for the die-cutting process to locate and remove the thickness abnormal segment. The grading control process includes: determining the thickness grade of the film roll based on the preset range of the difference between the average thickness of the whole roll and the average thickness of the standard roll, and sending the thickness grade result to the grade management device; the thickness grade is used for machine matching in the winding process.

9. The electrode thickness difference control system according to claim 8, characterized in that, The marking device includes a first marking machine and a second marking machine arranged at intervals along the electrode travel direction. The first marking machine and the thickness measuring device maintain a first fixed distance D1 along the travel direction, and the second marking machine and the thickness measuring device maintain a second fixed distance D2 along the travel direction, where D2 > D1. The control device is further configured to: An abnormal starting position mark is set at the first marking machine with a marking delay time T1 = D1 / V, and an abnormal ending position mark is set at the second marking machine with a marking delay time T2 = D2 / V. From the moment the starting position of the thickness abnormal segment is detected, after the marking delay time T1, the first marking machine is controlled to trigger the marking action to mark the abnormal mark at the starting position; From the moment the termination position of the thickness abnormal segment is detected, after the marking delay time T2, the second marking machine is controlled to trigger the marking action to mark the abnormal mark at the termination position.

10. The electrode thickness difference control system according to claim 8, characterized in that, The gear management device includes a manufacturing execution system; the manufacturing execution system is configured to: Receive the average thickness of the entire roll uploaded by the thickness measuring device, and calculate the difference between the average thickness of the entire roll and the average thickness of the standard roll. ; Based on the difference The preset range into which the film roll falls determines the corresponding thickness range. The thickness level is automatically written into the shipment identifier of the film roll, so that the winding process can read the shipment identifier and allocate the film roll to the winding equipment corresponding to the thickness level.

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