A novel method and system for detecting the coating area density of a power battery

Abstract

The present application relates to a kind of novel power battery coating area density detection identification method, the thickness quality before and after coating can be detected by two groups of laser arrays.In addition, the thickness of substrate is detected based on laser array 1, the area density value of substrate is obtained, the average area density of coated substrate and coating is obtained by double area density instrument detection, finally the area density values obtained in the same position are subtracted, and the coating area density data of single layer is obtained;According to the thickness data, the area of thickness qualified or unqualified is judged to obtain thickness detection result, according to the area density data, the area of area density qualified or unqualified is judged to obtain area density detection result;According to the thickness detection result, area density detection result and visual detection result, ink-jet printer is controlled according to preset identification relationship and is sprayed.The present application can reduce the evaluation range of unqualified area of thickness detection and area density detection, and reduce the product waste caused by the large error of unqualified product area in actual detection.

Description

Technical Field

[0001] This invention relates to the field of coating measurement technology, and in particular to a novel method and system for detecting and marking the surface density of coatings on power batteries. Background Technology

[0002] The production of new energy power batteries includes ten processes such as positive and negative electrode slurry preparation, coating, and rolling. Among these, coating and rolling, as pre-processes, are crucial for ensuring the consistency of battery performance and improving the energy density of the power batteries. These two pre-processes involve various inspections, including areal density testing, surface quality testing, thickness testing, and defect detection. There are over 200 types of defects, so processing and inspection efficiency accounts for 30% of the overall production efficiency, directly determining the quality and efficiency of subsequent production processes and the operating speed of the entire production line. Currently, the error in marking defective areas reaches ±30cm. Cutting off defective sections according to this error would result in a defect rate of 15% in the existing pre-process coating and rolling stages of new energy power battery production.

[0003] Most existing detection methods employ the following two patents: "CN207181212U A Device for Rapidly Measuring Coating Surface Density" and "CN102944498A Online Surface Density Detection System and Method for Battery Electrode Coating Production Line". Both patents describe devices and methods applicable to the surface density detection of lithium battery electrode coatings. Patent "CN207181212U A Device for Rapidly Measuring Coating Surface Density" uses manual sampling measurement. A pedal-controlled punch moves up and down, working in conjunction with a lower die to cut a sample, which is then weighed using an electronic scale to obtain the surface density value. However, this method is inefficient, has a very limited number of sampling points, wastes material, and cannot monitor and display the surface density value and its changes in real time. Patent "CN102944498A Online Surface Density Detection System and Method for Battery Electrode Coating Production Line" uses X-ray detection of surface density, which can obtain the real-time electrode surface density value and its changing trend.

[0004] Existing online areal density detection mainly employs radiographic areal density technology, specifically beta-ray areal density meters and X-ray areal density meters. The scanner probe scans back and forth to detect the online areal density value and its changing trend. Existing solutions, such as "CN102944498A - Online Areal Density Detection System and Detection Method for Battery Electrode Coating Production Line," also utilize radiographic areal density detection technology. However, single-area density detection suffers from several drawbacks: a complete missed detection zone (the width corresponding to the commutation time), a missed detection zone (in actual detection, a line is formed by the trajectory points of the detection circle area, and a thick diagonal line is drawn with the diameter of the detection circle; other areas within the rectangle diagonally opposite this thick diagonal line are missed detection zones, but this is unavoidable), and only one detection point along the perpendicular coating direction, resulting in low detection accuracy.

[0005] In addition, based on the technical principle of X-ray detection of areal density:

[0006] ; ;

[0007] I0 is the intensity of the radiation before transmission; I is the intensity of the radiation after transmission; μ is the absorption coefficient of the target being measured. ρ is the density of the target being measured; h is the thickness of the target being measured. Let be the surface density of the target object; e is a mathematical constant.

[0008] Currently, most companies measure surface density by using a scanning trajectory co-position control technology to enable multiple surface density measuring instruments to measure the coating surface density along the same trajectory. The surface density of single-sided or double-sided coating is obtained by subtracting the surface density data measured in the same position.

[0009] Regarding the labeling methods for testing, most lithium battery manufacturers currently use manual or labeling machine-based methods. These methods not only have low labeling accuracy and efficiency, but also affect the winding of lithium battery electrodes, causing wrinkles. Summary of the Invention

[0010] The purpose of this invention is to at least address one of the shortcomings of the prior art and provide a novel method and system for detecting and marking the surface density of power battery coatings.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] Specifically, a novel method for detecting and marking the surface density of power battery coatings is proposed, including the following:

[0013] Obtain the coated and dried lithium battery electrode sheet;

[0014] The thickness of the lithium battery electrode is measured using two sets of line laser arrays to obtain thickness data.

[0015] The areal density of the lithium battery electrode is measured using two sets of X-ray inspection units. A novel scheme for measuring and calculating areal density is proposed. Based on laser thickness measurement, the real-time thickness can be detected and the areal density measurement relationship can be corrected to obtain the areal density value of the substrate. The average areal density of the coated substrate and coating is obtained by measuring the areal density of the coated substrate using a bifacial density meter. Finally, the areal density of a single layer of coating is obtained by subtracting the areal density values ​​obtained from the same location in two separate measurements.

[0016] Based on the thickness data, areas that are qualified or unqualified in thickness are determined to obtain thickness detection results; based on the areal density data, areas that are qualified or unqualified in areal density are determined to obtain areal density detection results.

[0017] The thickness detection result, surface density detection result, and visual inspection result are obtained, and the inkjet printer is controlled to print according to the preset marking relationship based on the thickness detection result, surface density detection result, and visual inspection result.

[0018] Furthermore, specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units scan in a parallel, unidirectional manner.

[0019] The scanning trajectory of the first surface densitometer:

[0020] ;

[0021] ;

[0022] The scanning trajectory of the second surface densitometer:

[0023] ;

[0024] ;

[0025] The spacing between the two sets of X-ray scanning units is half the width of the lithium battery electrode, and the corresponding stroke of the synchronous belt slide module is half the width of the electrode.

[0026] Furthermore, specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units are scanned by non-parallel, unidirectional motion.

[0027] Furthermore, specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units are scanned by non-parallel reverse motion.

[0028] Furthermore, specifically, the areal density data is obtained by correcting the thickness data, including the following:

[0029] The areal density of the substrate can be obtained from the thickness data obtained by thickness measurement. The average areal density of the substrate and coating after coating can be obtained by areal density measurement. Finally, the areal density of a single layer of coating can be obtained by subtracting the areal density of the substrate from the average areal density of the substrate and coating obtained from two measurements at the same location.

[0030] The technical principle of obtaining the areal density of a substrate based on thickness data obtained from thickness measurement:

[0031] I = * (1);

[0032] = *h (2);

[0033] in, Let I be the intensity of the radiation before transmission, I be the intensity of the radiation after transmission, and μ be the absorption coefficient of the target being measured. Let h be the volume density of the target being measured, and h be the thickness of the target being measured. Let be the surface density of the target object, and e be a mathematical constant.

[0034] Areal density of substrate before coating The calculation formula is as follows:

[0035] Before single-layer coating: = *h 01 (3);

[0036] in Assuming the bulk density of the substrate before coating is a known constant, h 01 The thickness of the substrate is obtained by laser array detection. To calculate the areal density of the substrate before coating,

[0037] After single-layer coating: = * (4);

[0038] = * (5);

[0039] in, The intensity of the radiation before transmission. The intensity of the transmitted rays after a single-layer coating is given. 总 For the constants calibrated by the sample, The average areal density of the substrate and the coating layer after coating. The total thickness of the target being measured. The total areal density of the target being measured

[0040] The coating surface density of a single-layer coating can be obtained using equations (3) and (5):

[0041] = - .

[0042] Furthermore, specifically, the pre-defined identification relationships in the thickness detection results include the following:

[0043] The distance between the line laser array and the inkjet printer is L. JP Let the coating speed be V, the detection signal occurrence time be t0, the central processing unit processing and response time be t1, the transmission time to the inkjet printer be t2, and the inkjet printer response and printing time be t3. Then the relationship between thickness detection and inkjet printer marking is as follows:

[0044] The time from detecting the thickness defect to completing the inkjet printing is ts, where ts = t0 + t1 + t2 + t3;

[0045] The distance L between the inkjet printer and the laser detection point JP L JP ≥V*ts;

[0046] The printing delay time tdelay, tdelay = L JP / V-ts .

[0047] Furthermore, specifically, the pre-defined identification relationship of the areal density test results is as follows:

[0048] The coating speed is V, and the scanning speed of the double-sided density meter in the same direction is Vm; the coating width is B, the total scanning width of the double-sided density meter is Bm, the distance between the double-sided density meters in the same direction is Bm / 2, and the distance between the density meter and the marking system is Lmp; time-related parameters include: the scanning cycle T of the density meter, the reversal time td of the density meter, the communication and calculation time tc1 between the double-sided density meter and the central processing unit, the communication time tc2 between the central processing unit and the marking system, the response and printing time of the marking system tp, and the system response time ts. Here, the subscript m represents density detection, p represents the marking system inkjet printer, and c represents communication. The relationship between the double-sided density meter detection and the inkjet printer marking is as follows:

[0049] The system response time is ts', where ts' = tc1 + tc2 + tp.

[0050] The distance Lmp between the inkjet printer and the X-ray unit detection point is Lmp ≥ V*ts.

[0051] The delay response printing time of the labeling system is tdelay'=Lmp / V-ts.

[0052] Furthermore, the method also includes the following rule being met when the inkjet printer performs printing:

[0053] When surface density detection, thickness detection, and visual inspection fail, the inkjet printing delay tdelay will print a pass mark, a cutting scale mark, and a fail mark.

[0054] Continue to inspect the non-conforming situation until it is qualified, then delay the inkjet printing time (tdelay), print a non-conforming mark, cut off the scale markings and print a qualified mark;

[0055] When at least one type of non-conforming area exists simultaneously in surface density detection, thickness detection, and visual inspection, and these areas overlap, the position from the point where a certain type of detection signal is first detected to the point where the detection passes or fails is... Identify all overlapping non-conforming areas, i.e., the last inspection point, and determine the position from non-conforming to conforming. The width of the lithium battery electrode is B, and the area of ​​the defective region can be expressed as: The calculation method for a single type of non-conforming area is the same as the process described above.

[0056] This invention also proposes a novel power battery coating surface density detection and marking system, which applies the aforementioned novel power battery coating surface density detection and marking method, including the following:

[0057] The thickness detection module is used to detect the thickness of lithium battery electrodes and obtain thickness data.

[0058] The areal density detection module includes two sets of X-ray detection units, which are used to detect the areal density of lithium battery electrodes to obtain areal density data;

[0059] The vision inspection module is used for CCD vision inspection of lithium battery electrodes;

[0060] Inkjet printers are used for marking and printing labels.

[0061] Central processing unit, including,

[0062] The test object acquisition module is used to acquire the coated and dried lithium battery electrode sheets.

[0063] The thickness data acquisition module is used to obtain thickness data by performing thickness detection on the lithium battery electrode sheet using two sets of line laser arrays.

[0064] The areal density data acquisition module is used to detect the areal density of the lithium battery electrode sheet using two sets of X-ray detection units. Laser thickness measurement can detect the real-time thickness and correct the areal density measurement relationship to obtain the areal density value of the substrate. The average areal density of the coated substrate and coating is obtained by detecting the areal density of the coated substrate and coating using a double-sided density meter. Finally, the areal density of a single layer of coating is obtained by subtracting the areal density values ​​obtained from the same location twice.

[0065] The detection result judgment module is used to determine the thickness detection result by judging the area where the thickness is qualified or unqualified based on the thickness data, and to determine the area where the surface density is qualified or unqualified based on the surface density data;

[0066] The printing module is used to acquire thickness detection results, surface density detection results, and visual inspection results, and to control the inkjet printer to print according to the preset marking relationship based on the thickness detection results, surface density detection results, and visual inspection results.

[0067] The beneficial effects of this invention are as follows:

[0068] In terms of detection methods, compared with manual sampling and measurement of surface density, using X-ray detection of surface density can achieve real-time surface density detection and obtain the value and changes of surface density, resulting in higher detection efficiency and accuracy. Compared with single-surface density detection equipment, using double-surface density detection equipment can double the detection accuracy and eliminate the complete missed detection area caused by single-surface density detection.

[0069] Regarding the labeling method for detection, compared with the labeling method based on manual or labeling machine, the proposed labeling method based on double-sided density detection equipment and automatic inkjet printer effectively solves the shortcomings of manual or labeling machine labeling, improves the accuracy and efficiency of labeling, and facilitates highly automated integration of processes such as machine vision recognition and automatic cutting.

[0070] Based on the principle of areal density detection, a novel scheme for measuring and calculating areal density is proposed. This scheme utilizes laser thickness measurement to detect real-time thickness and correct the areal density measurement relationship to obtain the areal density value of the substrate. The average areal density of the coated substrate and coating is obtained by measuring with a bifacial density meter. Finally, subtracting the areal density values ​​obtained from two measurements at the same location yields the areal density of the single-layer coating. Attached Figure Description

[0071] The above and other features of this disclosure will become more apparent from the detailed description of the embodiments shown in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals denote the same or similar output voltages. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort. In the drawings:

[0072] Figure 1 The diagram shows a flowchart of a novel method for detecting and marking the surface density of a power battery coating according to the present invention.

[0073] Figure 2 The diagram shown is a schematic diagram of the thickness detection principle of a novel power battery coating surface density detection and marking method according to the present invention.

[0074] Figure 3 The above is a schematic diagram illustrating the principle of measuring thickness and surface density in a novel power battery coating surface density detection and marking method of the present invention.

[0075] Figure 4 The diagram shows the installation of a novel power battery coating surface density detection and marking method according to the present invention, which includes laser array thickness measurement, double-sided density meter detection of surface density, CCD defect detection, and inkjet printing.

[0076] Figure 5 The image shows a schematic diagram of the scanning trajectory of a single-sided density detection device.

[0077] Figure 6 The diagram shows the parallel, unidirectional scanning trajectories of two sets of X-ray detection units performing surface density detection in Embodiment 1 of a novel power battery coating surface density detection and marking method of the present invention.

[0078] Figure 7 The diagram shown is a schematic diagram of the non-side-by-side unidirectional scanning trajectory of two sets of X-ray detection units performing surface density detection in Embodiment 2 of a novel power battery coating surface density detection and marking method of the present invention.

[0079] Figure 8 The diagram shown is a schematic diagram of the non-side-by-side reverse scanning trajectory of two sets of X-ray detection units performing surface density detection in Embodiment 3 of a novel power battery coating surface density detection and marking method of the present invention.

[0080] Figure 9 The diagram shows a schematic of the marking type for a novel power battery coating surface density detection and marking method according to the present invention. Detailed Implementation

[0081] The following will provide a clear and complete description of 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, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The same reference numerals used throughout the accompanying drawings indicate the same or similar parts.

[0082] Reference Figure 1 This invention proposes a novel method for detecting and marking the surface density of a power battery coating, comprising the following:

[0083] Step 110: Obtain the coated and dried lithium battery electrode sheet;

[0084] Step 120, Combining Figure 2 The thickness of the lithium battery electrode is measured using two sets of line laser arrays to obtain thickness data.

[0085] Step 130, Combining Figure 3 The thickness of the lithium battery electrode before and after coating is detected using two sets of laser arrays. The thickness of the substrate is also detected based on laser array 1 to obtain the areal density value of the substrate. The average areal density of the coated substrate and coating layer is obtained using a bifacial density meter. Finally, the areal density data of a single-layer coating layer is obtained by subtracting the areal density values ​​obtained from the two measurements at the same location.

[0086] Step 140: Based on the thickness data, determine the areas where the thickness is qualified or unqualified to obtain the thickness detection result; based on the areal density data, determine the areas where the areal density is qualified or unqualified to obtain the areal density detection result.

[0087] Step 150, Combining Figure 4 The thickness detection result, surface density detection result, and visual inspection result are obtained, and the inkjet printer is controlled to print according to the preset marking relationship based on the thickness detection result, surface density detection result, and visual inspection result.

[0088] This method can replace conventional methods of reciprocating inspection with a single surface density meter and methods based on manual or labeling machine marking of inspection status. While replacing single-laser reciprocating scanning thickness measurement with line laser array thickness measurement, it also corrects the measurement relationship based on radiographic surface density, reduces the assessment range of non-conforming areas in thickness and surface density detection, improves inspection efficiency, and enhances the efficiency and quality of marking non-conforming areas (thickness, surface density, and visual inspection defects), thereby reducing product waste caused by large errors in the actual inspection of non-conforming areas.

[0089] In Example 1, specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units scan in a parallel, unidirectional manner.

[0090] The scanning trajectory of the first surface densitometer:

[0091] ;

[0092] ;

[0093] The scanning trajectory of the second surface densitometer:

[0094] ;

[0095] ;

[0096] The spacing between the two sets of X-ray scanning units is half the width of the lithium battery electrode, and the corresponding stroke of the synchronous belt slide module is half the width of the electrode.

[0097] In this embodiment 1,

[0098] The dual-sided density detector uses a parallel, unidirectional scanning method. To accommodate different types of lithium battery electrodes, the spacing between the two density scanners can be adjusted arbitrarily according to the electrode width. The scanner spacing needs to be adjusted to half the electrode width, and the travel of the synchronous belt slide module is also half the electrode width. Addressing the issues of complete missed detection areas and low accuracy in single-sided density detection, the dual-sided density detector eliminates these areas. Furthermore, because the bidirectional detection travels half the distance of the original method, the missed detection area is halved. Considering the intersection of the two methods, two points are detected on each detection line perpendicular to the coating direction, doubling the detection accuracy. Moreover, the mid-way reversal eliminates, to some extent, the complete missed detection area caused by the reversal during single-sided density scanning. The scanning trajectories of the single-sided and dual-sided density detectors are as follows: Figure 5 , Figure 6 As shown.

[0099] To address the issues of complete missed detection areas and low detection accuracy in single-sided density detection, double-sided density detection can eliminate complete missed detection areas. Moreover, because the bidirectional detection travels half the distance of the original detection, the missed detection area is reduced by half. Considering the intersection of the two methods, each measurement line detects two points, doubling the detection accuracy. Furthermore, the reversal in the middle further eliminates complete missed detection areas to some extent.

[0100] Reference Figure 7 In Example 2, specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units are scanned by non-parallel, unidirectional motion.

[0101] In this embodiment, the detection effect in Embodiment 1 can also be achieved by arranging the X-ray detection units in the manner described above. However, since the two sets of X-ray detection units are not side by side, the two sets of X-ray detection units must be designed as two scanning devices. Compared with Embodiment 1, the structure of the device is more complex, the area occupied is larger, and resources are wasted.

[0102] Reference Figure 8 In Example 3, specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units are scanned by non-parallel reverse motion.

[0103] In this embodiment, the detection effect in Embodiment 1 can also be achieved by arranging the X-ray detection units in the manner described above. However, since the two sets of X-ray detection units are not side by side, the two sets of X-ray detection units must be designed as two scanning devices. Compared with Embodiment 1, the structure of the device is more complex, the area occupied is larger, and resources are wasted.

[0104] In a preferred embodiment of the present invention, specifically, the areal density data is obtained by correcting the thickness data, including the following:

[0105] The areal density of the substrate can be obtained from the thickness data obtained by thickness measurement. The average areal density of the substrate and coating after coating can be obtained by areal density measurement. Finally, the areal density of a single layer of coating can be obtained by subtracting the areal density of the substrate from the average areal density of the substrate and coating obtained from two measurements at the same location.

[0106] The technical principle of obtaining the areal density of a substrate based on thickness data obtained from thickness measurement:

[0107] (1);

[0108] (2);

[0109] in, Let I be the intensity of the radiation before transmission, I be the intensity of the radiation after transmission, and μ be the absorption coefficient of the target being measured. Let h be the volume density of the target being measured, and h be the thickness of the target being measured. Let be the surface density of the target object, and e be a mathematical constant.

[0110] Areal density of substrate before coating The calculation formula is as follows:

[0111] Before single-layer coating: = *h 01 (3);

[0112] in Assuming the bulk density of the substrate before coating is a known constant, h 01 The thickness of the substrate is obtained by laser array detection. To calculate the areal density of the substrate before coating,

[0113] After single-layer coating: = * (4);

[0114] = * (5);

[0115] in, The intensity of the radiation before transmission. The intensity of the transmitted rays after a single-layer coating is given. 总 For the constants calibrated by the sample, The average areal density of the substrate and the coating layer after coating. The total thickness of the target being measured. The total areal density of the target being measured

[0116] The coating surface density of a single-layer coating can be obtained using equations (3) and (5):

[0117] = - .

[0118] In a preferred embodiment of the present invention, the preset identification relationship of the thickness detection results specifically includes the following:

[0119] The distance between the line laser array and the inkjet printer is L. JP Let the coating speed be V, the detection signal occurrence time be t0, the central processing unit processing and response time be t1, the transmission time to the inkjet printer be t2, and the inkjet printer response and printing time be t3. Then the relationship between thickness detection and inkjet printer marking is as follows:

[0120] The time from detecting the thickness defect to completing the inkjet printing is ts, where ts = t0 + t1 + t2 + t3;

[0121] The distance L between the inkjet printer and the laser detection point JP LJP≥V*ts;

[0122] The printing delay time tdelay, tdelay = L JP / V-ts .

[0123] In a preferred embodiment of the present invention, the pre-defined identification relationship of the areal density detection results is as follows:

[0124] The coating speed is V, and the scanning speed of the double-sided density meter in the same direction is Vm; the coating width is B, the total scanning width of the double-sided density meter is Bm, the distance between the double-sided density meters in the same direction is Bm / 2, and the distance between the density meter and the marking system is Lmp; time-related parameters include: the scanning cycle T of the density meter, the reversal time td of the density meter, the communication and calculation time tc1 between the double-sided density meter and the central processing unit, the communication time tc2 between the central processing unit and the marking system, the response and printing time of the marking system tp, and the system response time ts. Here, the subscript m represents density detection, p represents the marking system inkjet printer, and c represents communication. The relationship between the double-sided density meter detection and the inkjet printer marking is as follows:

[0125] The system response time is ts', where ts' = tc1 + tc2 + tp.

[0126] The distance Lmp between the inkjet printer and the X-ray unit detection point is Lmp ≥ V*ts.

[0127] The delay response printing time of the labeling system is tdelay'=Lmp / V-ts.

[0128] By pre-setting the labeling relationships, the labeling process can be automated, effectively solving the shortcomings of manual or labeling machine labeling, improving the accuracy and efficiency of labeling, and facilitating highly automated integration of processes such as machine vision recognition and automatic cutting.

[0129] In a preferred embodiment of the present invention, the method further includes that the inkjet printer satisfies the following rules during printing.

[0130] When surface density detection, thickness detection, and visual inspection fail, the inkjet printing delay tdelay will print a pass mark, a cutting scale mark, and a fail mark.

[0131] Continue to inspect the non-conforming situation until it is qualified, then delay the inkjet printing time (tdelay), print a non-conforming mark, cut off the scale markings and print a qualified mark;

[0132] When at least one type of non-conforming area exists simultaneously in surface density detection, thickness detection, and visual inspection, and these areas overlap, the position from the point where a certain type of detection signal is first detected to the point where the detection passes or fails is... Identify all overlapping non-conforming areas, i.e., the last inspection point, and determine the position from non-conforming to conforming. The width of the lithium battery electrode is B, and the area of ​​the defective region can be expressed as: The calculation method for a single type of non-conforming area is the same as the process described above.

[0133] Reference Figure 9At the starting position, three types of pass / fail indicators and arrows are printed to indicate the type of printing and the direction of rewinding. The arrows on the indicators show the direction and the corresponding pass / fail area. Pass and fail appear simultaneously, and cutting scale lines are printed in the middle of the inspection point to facilitate subsequent machine identification and cutting operations. To prevent overlapping of multiple types of fail areas, different types of patterns should be printed at different heights. When multiple types of fail areas overlap, the process ends with identifying all types of fail areas, which serves as the total fail area and the cutting range.

[0134] In this embodiment, the algorithm for determining the size of the defective area (including surface density, thickness, and visual detection) based on the detection marking method of the double-sided density detection equipment can accurately determine the size of the defective area, facilitating subsequent intelligent cutting.

[0135] This invention also proposes a novel power battery coating surface density detection and marking system, which applies the aforementioned novel power battery coating surface density detection and marking method, including the following:

[0136] The thickness detection module is used to detect the thickness of lithium battery electrodes and obtain thickness data.

[0137] The areal density detection module includes two sets of X-ray detection units, which are used to detect the areal density of lithium battery electrodes to obtain areal density data;

[0138] The vision inspection module is used for CCD vision inspection of lithium battery electrodes;

[0139] Inkjet printers are used for marking and printing labels.

[0140] Central processing unit, including,

[0141] The test object acquisition module is used to acquire the coated and dried lithium battery electrode sheets.

[0142] The thickness data acquisition module is used to obtain thickness data by performing thickness detection on the lithium battery electrode sheet using two sets of line laser arrays.

[0143] The areal density data acquisition module is used to detect the thickness of the lithium battery electrode sheet before and after coating using two sets of laser arrays, and to detect the thickness of the substrate based on laser array 1, thereby obtaining the areal density value of the substrate. The average areal density of the substrate and coating after coating is obtained by measuring the areal density of a bifacial density meter. Finally, subtracting the areal density values ​​obtained from the same location twice yields the areal density data of the single-layer coating.

[0144] The detection result judgment module is used to determine the thickness detection result by judging the area where the thickness is qualified or unqualified based on the thickness data, and to determine the area where the surface density is qualified or unqualified based on the surface density data;

[0145] The printing module is used to acquire thickness detection results, surface density detection results, and visual inspection results, and to control the inkjet printer to print according to the preset marking relationship based on the thickness detection results, surface density detection results, and visual inspection results.

[0146] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment, depending on actual needs.

[0147] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0148] If the integrated module is implemented as a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0149] Although the description of the invention has been quite detailed and particularly of several described embodiments, it is not intended to limit it to any of these details or embodiments or any particular embodiment, but should be considered as providing a broad possible interpretation of the claims by referring to the appended claims and taking into account the prior art, thereby effectively covering the intended scope of the invention. Furthermore, the invention has been described above with respect to embodiments foreseeable by the inventors in order to provide a useful description, and non-substantial modifications to the invention that have not yet been foreseen may still represent equivalent modifications.

[0150] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. Any embodiment that achieves the technical effects of the present invention using the same means should fall within the protection scope of the present invention. Within the protection scope of the present invention, various modifications and variations can be made to the technical solutions and / or implementation methods.

Claims

1. A novel method for detecting and marking the surface density of a power battery coating, characterized in that, Including the following: Obtain the coated and dried lithium battery electrode sheet; The thickness of the lithium battery electrode is measured using two sets of line laser arrays to obtain thickness data. The areal density of the lithium battery electrode is detected by two sets of X-ray detection units, and the areal density data is obtained by combining the thickness data. Based on the thickness data, areas that are qualified or unqualified in thickness are determined to obtain thickness detection results; based on the areal density data, areas that are qualified or unqualified in areal density are determined to obtain areal density detection results. Obtain thickness detection results, areal density detection results, and visual inspection results, and control the inkjet printer to print according to the preset marking relationship based on the thickness detection results, areal density detection results, and visual inspection results; Specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units scan in a parallel, unidirectional manner. The scanning trajectory of the first surface densitometer: ； ； The scanning trajectory of the second surface densitometer: ； ； The spacing between the two sets of X-ray scanning units is half the width of the lithium battery electrode, and the corresponding stroke of the synchronous belt slide module is half the width of the electrode.

2. The novel method for detecting and marking the surface density of a power battery coating according to claim 1, characterized in that, Specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units are scanned by non-parallel, unidirectional motion.

3. The novel method for detecting and marking the surface density of a power battery coating according to claim 1, characterized in that, Specifically, when the areal density of the lithium battery electrode is detected by two sets of X-ray detection units, the two sets of X-ray detection units are scanned by non-parallel reverse motion.

4. The novel method for detecting and marking the surface density of a power battery coating according to claim 1, characterized in that, Specifically, the areal density data is obtained by correcting the thickness data, including the following: The areal density of the substrate can be obtained from the thickness data obtained by thickness measurement. The average areal density of the substrate and coating after coating can be obtained by areal density measurement. Finally, the areal density of a single layer of coating can be obtained by subtracting the areal density of the substrate from the average areal density of the substrate and coating obtained from two measurements at the same location. The technical principle of obtaining the areal density of a substrate based on thickness data obtained from thickness measurement: （1）； （2）； in, Let I be the intensity of the radiation before transmission, I be the intensity of the radiation after transmission, and μ be the absorption coefficient of the target being measured. Let h be the volume density of the target being measured, and h be the thickness of the target being measured. Let be the surface density of the target object, and e be a mathematical constant. Areal density of substrate before coating The calculation formula is as follows: Before single-layer coating: = *h 01 (3); in Assuming the bulk density of the substrate before coating is a known constant, h 01 The thickness of the substrate is obtained by laser array detection. To calculate the areal density of the substrate before coating, After single-layer coating: = * (4); = * （5）； in, The intensity of the radiation before transmission. The intensity of the transmitted rays after a single-layer coating is given. 总 For the constants calibrated by the sample, The average areal density of the substrate and the coating layer after coating. The total thickness of the target being measured. The total areal density of the target being measured The coating surface density of a single-layer coating can be obtained using equations (3) and (5): = - 。 5. The novel method for detecting and marking the surface density of a power battery coating according to claim 1, characterized in that, Specifically, the preset identification relationships in the thickness detection results include the following: The distance between the line laser array and the inkjet printer is L. JP If the coating speed is V, the detection signal generation time is t0, the central processing unit processing and response time is t1, the transmission time to the inkjet printer is t2, and the inkjet printer response and printing time is t3, then the relationship between thickness detection and inkjet printer marking is as follows: The time from detecting the thickness defect to completing the inkjet printing is ts, where ts = t0 + t1 + t2 + t3; The distance L between the inkjet printer and the laser detection point JP L JP ≥V*ts; The printing delay time tdelay, tdelay = LJP / V-ts.

6. The novel method for detecting and marking the surface density of a power battery coating according to claim 1, characterized in that, Specifically, the pre-defined identification relationship of the areal density test results is as follows: The coating speed is V, and the scanning speed of the double-sided density meter in the same direction is Vm; the coating width is B, the total scanning width of the double-sided density meter is Bm, the distance between the double-sided density meters in the same direction is Bm / 2, and the distance between the density meter and the marking system is Lmp; time-related parameters include: the scanning cycle T of the density meter, the reversal time td of the density meter, the communication and calculation time tc1 between the double-sided density meter and the central processing unit, the communication time tc2 between the central processing unit and the marking system, the response and printing time of the marking system tp, and the system response time ts. Here, the subscript m represents density detection, p represents the marking system inkjet printer, and c represents communication. The relationship between the double-sided density meter detection and the inkjet printer marking is as follows: System response time ts', ts' = tc1 + tc2 + tp; The distance between the inkjet printer and the X-ray unit detection point is Lmp, where Lmp ≥ V*ts; The delay response printing time of the labeling system is tdelay'=Lmp / V-ts.

7. The novel method for detecting and marking the surface density of a power battery coating according to claim 1, characterized in that, The method further includes the inkjet printer satisfying the following rules during printing. When surface density detection, thickness detection, and visual inspection fail, the inkjet printing delay tdelay will print a pass mark, a cutting scale line, and a fail mark. Continue to inspect the non-conforming situation until it is qualified, then delay the inkjet printing time (tdelay), print a non-conforming mark, cut off the scale markings and print a qualified mark; When at least one type of non-conforming area exists simultaneously in surface density detection, thickness detection, and visual inspection, and these areas overlap, the position from the point where a certain type of detection signal is first detected to the point where the detection passes or fails is... Identify all overlapping non-conforming areas, i.e., the last inspection point, and determine the position from non-conforming to conforming. The width of the lithium battery electrode is B, and the area of ​​the defective region can be expressed as: The calculation method for a single type of non-conforming area is the same as the process described above.

8. A novel power battery coating surface density detection and marking system, characterized in that, A novel method for detecting and marking the surface density of a power battery coating, using any one of claims 1-7, comprises the following: The thickness detection module is used to detect the thickness of lithium battery electrodes and obtain thickness data. The areal density detection module includes two sets of X-ray detection units, which are used to detect the areal density of lithium battery electrodes to obtain areal density data; The vision inspection module is used for CCD vision inspection of lithium battery electrodes; Inkjet printers are used for marking and printing labels. Central processing unit, including, The test object acquisition module is used to acquire the coated and dried lithium battery electrode sheets. The thickness data acquisition module is used to obtain thickness data by performing thickness detection on the lithium battery electrode sheet using two sets of line laser arrays. The areal density data acquisition module is used to detect the areal density of the lithium battery electrode sheet through two sets of X-ray detection units, and to correct it in combination with the thickness data to obtain the areal density data. The detection result judgment module is used to determine the thickness detection result by judging the area where the thickness is qualified or unqualified based on the thickness data, and to determine the area where the surface density is qualified or unqualified based on the surface density data; The printing module is used to acquire thickness detection results, surface density detection results, and visual inspection results, and to control the inkjet printer to print according to the preset marking relationship based on the thickness detection results, surface density detection results, and visual inspection results.

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