Pole piece slitting system and method

Abstract

The invention provides a pole piece slitting system and method. The pole piece slitting system and method can be applied to the pole piece slitting procedure in the battery production process. According to the invention, the information of the pole piece is collected in real time, the deviation and appearance defect detection is carried out on the pole piece, and the automatic deviation correction closed loop and appearance defect alarm reminding of the pole piece are realized. And batch scrapping of the pole pieces is reduced by real-time automatic deviation rectification. Defects are found and alarmed in time, so that defective pole pieces are prevented from flowing into the subsequent production process. According to the pole piece slitting system and method, the pole piece yield and the production efficiency are improved, manual detection is replaced with automatic detection, the labor cost is reduced, the product stability is improved, and the personnel safety is guaranteed.

Description

Technical Field

[0001] The present application relates to the field of battery production technology, and in particular to a slitting system and method in a battery pole piece production process. Background Art

[0002] The process of making pole pieces for battery cells includes pre-processes such as slurry stirring, coating, cold pressing, pre-slitting, and die cutting. Among them, the coating process is to evenly coat the slurry on the surface of the current collector, and after drying, form the positive and negative pole piece strips and roll them up. After coating, it enters the cold pressing process, where the pole piece strip is rolled by a roller so that the porous coating layer is compacted and firmly bonded to the foil, and a pole piece with thickness and compaction density that meets the specification requirements is obtained.

[0003] During the production process, the pole piece is generally transported by rollers and other instruments. Taking the slitting of the pole piece of the wound battery as an example, the pole piece is cut into two parts by a cutter, and the two parts of the pole piece are separately rolled up along the upper and lower flat rollers to obtain two parts of the material roll. The current slitting equipment manually adjusts the width deviation and appearance defects of the pole piece, which cannot be adjusted in real time, often resulting in batch scrapping, affecting the yield rate of subsequent production and reducing production efficiency. Summary of the invention

[0004] To this end, the present application provides a pole piece cutting system and cutting method for real-time detection of pole piece offset. In the production process of pole piece cutting, the pole piece automatic deviation correction closed loop can be realized to ensure the consistency of battery cell capacity and reduce the batch scrapping of pole pieces. Thereby improving the pole piece yield and production efficiency, ensuring personnel safety, and improving battery performance. Specifically, the present application includes the following technical solutions:

[0005] On the one hand, the present application provides a pole piece cutting system, comprising: a pole piece cutting device, used to cut a first pole piece into multiple second pole pieces, wherein the width of the first pole piece is greater than that of the second pole piece; an information acquisition module, used to collect information of the second pole piece; and a processor, used to obtain the information and determine whether the second pole piece is offset based on the information, and when an offset occurs, the processor corrects the first pole piece.

[0006] The pole piece cutting system proposed in this application can detect pole piece information in real time during the pole piece cutting process of the battery cell. Compared with manual correction after manual sampling, it reduces the batch scrapping of pole pieces. It can also reduce production costs such as labor and materials. In addition, it can reduce the contact between personnel and machines and ensure personnel safety.

[0007] In some implementations, the information acquisition module includes an image acquisition module, preferably a charge coupled device camera.

[0008] Compared with other information acquisition systems, the image acquisition module has both cost and performance advantages, high maturity, and is easy for industrial application. As the preferred charge-coupled device camera, it has the advantages of high image quality, low noise, high sensitivity, and fast reading, and is widely used in product quality inspection in industrial production.

[0009] In some implementations, the system further includes a first roller and a second roller. The plurality of second pole pieces are numbered sequentially, wherein the first roller and the second roller are respectively used to convey the second pole pieces with odd numbers and the second pole pieces with even numbers after slitting.

[0010] Each of the first roller and the second roller conveys a plurality of second pole pieces, and only two rollers are used to convey the second pole pieces in two directions. Compared with the design that each second pole piece is conveyed in different directions by a separate roller, the system space is saved and the structure is simpler. Such a system is also easier to manufacture.

[0011] In some implementations, the information collection module includes a first information collection submodule, which is used to collect information of odd-numbered second pole pieces at the first roller.

[0012] In some implementations, the information collection module further includes a second information collection submodule for collecting information of even-numbered second pole pieces at the second roller.

[0013] The information collection module collects information about the pole piece at the roller shaft, rather than collecting information at other positions in the direction of pole piece transmission. Since the motion state of the pole piece at the roller shaft is relatively stable, the accuracy and quality of information collection can be improved.

[0014] In some implementations, the information of the second pole piece includes a width of the second pole piece, and accordingly, the offset includes a width offset, wherein a direction of the width is a direction perpendicular to a transmission direction of the second pole piece.

[0015] Compared with the information of angle offset, width offset is easier to obtain and process. By judging the width offset, it is determined whether correction is needed. It has low complexity and is easy to implement.

[0016] In some implementations, determining whether a width offset occurs includes: a processor calculating an offset of a width of the second pole piece compared to a standard width, and determining that the width offset occurs if the width offset is greater than a lower threshold of a width offset error.

[0017] In some implementations, if the width offset is less than the width offset error upper limit threshold, the processor calculates a correction value, and accordingly, the processor corrects the second pole piece, including correcting the second pole piece according to the correction value.

[0018] The error of the width deviation of each second pole piece is compared with the determined standard width, and the error is the correction value. The method is simple and convenient for the processor to calculate the correction value and correct the first pole piece.

[0019] In some implementations, if the width offset error is greater than or equal to the width offset upper limit threshold, the system alarms.

[0020] When the second pole piece exceeds the upper threshold of the width error, it is a defective product. At this time, an alarm is triggered and the machine is shut down, which makes it convenient for operators to deal with the pole piece to be scrapped in time, thereby improving production efficiency.

[0021] In some implementations, the system further includes a third roller for conveying the first pole piece, and accordingly, the information acquisition module further includes a third information acquisition submodule for acquiring information of the first pole piece at the third roller.

[0022] In some implementations, the first pole piece includes a first surface and a second surface, and the third information collection submodule collects information of the first surface of the first pole piece.

[0023] In some implementations, the second pole piece includes a first surface and a second surface, and the first information acquisition submodule and the second information acquisition submodule respectively acquire information of the second surface of the second pole piece.

[0024] Compared with the solution of collecting information on both sides of each pole piece, the above implementation method can not only completely collect information on the first and second sides of the pole piece, but also save system space and reduce the number of information collection modules.

[0025] In some implementations, the information of the first pole piece and / or the second pole piece also includes appearance information. Based on the appearance information, the processor is also used to determine whether the first pole piece and / or the second pole piece has appearance defects; if appearance defects occur, the alarm is notified to sound an alarm.

[0026] Detect appearance defects in the process of judging the deviation and correcting it, which improves the utilization rate of the information acquisition module. Real-time detection of appearance defects reduces the outflow of bad pole pieces. Timely alarm when defects occur, making it easier for operators to troubleshoot and locate faults.

[0027] In some implementations, the information acquisition module further includes a light source for supplementing light to the image acquisition module. The light source is easy to adjust, which can not only make the acquired image clearer, but also obtain multiple frames of image information under different lighting conditions, thereby improving detection accuracy.

[0028] In some implementations, the straight line from the center of the first roller to the radius of the contact point between the second pole piece and the first roller is the center line between the straight line from the image acquisition module to the contact point and the straight line from the light source to the contact point. This arrangement facilitates linkage adjustment of the image acquisition module and the light source.

[0029] On the other hand, the present application provides a pole piece cutting method, including: cutting a first pole piece into multiple second pole pieces, wherein the width of the first pole piece is greater than that of the second pole piece; collecting information of the second pole piece; and obtaining the information and determining whether the second pole piece is offset based on the information, and when an offset occurs, correcting the first pole piece.

[0030] The electrode slitting method proposed in the present application detects the offset of the electrode in real time during the electrode slitting process of the battery cell. Compared with manual correction after manual sampling, it reduces the batch scrapping of electrodes, improves the yield rate of electrode slitting, reduces production costs such as labor and materials, and at the same time reduces the contact between personnel and machines, ensuring personnel safety.

[0031] In some implementations, two rollers, a first roller and a second roller, are used to respectively convey the second pole pieces with odd numbers and the second pole pieces with even numbers after slitting.

[0032] Compared with the method of using a roller to transport each second pole piece in different directions, the multiple second pole pieces after being cut are transported in two directions. This saves more system space and is easier to design in structure.

[0033] In some implementations, collecting information about the second pole pieces includes collecting information about second pole pieces with odd numbers at the first roller and information about second pole pieces with even numbers at the second roller.

[0034] Since the motion state of the pole piece at the roller axis is relatively stable, collecting information of the pole piece at the roller axis can improve the quality of information collection.

[0035] In some implementations, the information of the second pole piece includes a width of the second pole piece, and accordingly, the offset includes a width offset, wherein a direction of the width is a direction perpendicular to a transmission direction of the second pole piece.

[0036] Compared with the information of angle offset, width offset is easier to obtain and process. By judging the width offset, it is determined whether correction is needed. It has low complexity and is easy to implement.

[0037] In some implementations, the method further includes collecting information of the first pole piece.

[0038] Before deviation correction, the appearance defects of the electrode are detected once, which is convenient for personnel to deal with defective electrodes in time, thereby improving the yield rate of production.

[0039] In some implementations, the method further includes: the information of the first pole piece and / or the second pole piece also includes appearance information, judging whether the first pole piece and / or the second pole piece has appearance defects according to the appearance information; and if appearance defects occur, an alarm is issued.

[0040] Detecting appearance defects during the process of determining the deviation and making corrections is conducive to effective correction. Real-time detection of appearance defects reduces the flow of defective products into subsequent processes, which is conducive to ensuring battery performance. Timely alarms when defects occur facilitate operators to troubleshoot and locate problems.

[0041] In some implementations, the appearance information includes appearance information of the first and second surfaces of the first pole piece and the second pole piece, preferably, includes appearance information of the first surface of the first pole piece and appearance information of the second surface of the second pole piece.

[0042] In this way, the information of the first and second surfaces of the pole piece can be completely collected, and there is no need to collect information on both surfaces of the first pole piece and each second pole piece, thereby reducing the waste of resources caused by repeated information collection.

[0043] The pole piece cutting system and method proposed in this application can realize the closed loop of automatic pole piece correction to ensure the consistency of battery cell capacity. It reduces the batch scrapping of pole pieces and saves material costs, thereby improving the pole piece yield and production efficiency. It can also monitor appearance defects in real time to reduce the outflow of bad pole pieces. In addition, it can also shut down the machine with early warning for defects, making it convenient for operators to troubleshoot and locate fault problems. It reduces the contact between personnel and production equipment and improves production safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0045] Figure 1 A schematic diagram of a pole piece cutting system according to an embodiment of the present application is shown;

[0046] Figure 2 A schematic diagram of a pole piece cutting system according to another embodiment of the present application is shown;

[0047] Figure 3 A schematic diagram of a pole piece cutting system according to another embodiment of the present application is shown;

[0048] Figure 4 A schematic diagram of an information collection module according to an embodiment of the present application is shown;

[0049] Figure 5 A schematic diagram of an information collection module according to an embodiment of the present application is shown;

[0050] Fig. 6A A schematic diagram of a second pole piece of an embodiment of the present application is shown;

[0051] Figure 6B A schematic diagram showing another second pole piece of an embodiment of the present application is shown;

[0052] Figure 7 A schematic diagram of a pole piece cutting system according to another embodiment of the present application is shown.

[0053] Figure 8 A flow chart of a pole piece cutting method according to an embodiment of the present application is shown;

[0054] Fig. 9 A flow chart showing an information collection method for a pole piece cutting method according to an embodiment of the present application is shown;

[0055] Fig.10 A flow chart showing a defect detection method of a pole piece cutting method according to an embodiment of the present application is shown; DETAILED DESCRIPTION

[0056] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0057] In the description of the present application, it should be noted that, unless otherwise specified, “plurality” means more than two; in addition, the terms “first”, “second”, “third”, etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0058] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0059] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0060] The term "plurality" used in the present application refers to two or more (including two).

[0061] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0062] In the production process of battery cell pole pieces, the current slitting equipment cannot detect pole pieces in real time, and deviations can easily cause batch scrapping. Operators only perform regular spot checks and visual inspections of pole pieces during production. When pole piece size deviations are detected, manual corrections are performed, which cannot be adjusted in real time, often resulting in batch scrapping and affecting production efficiency.

[0063] The electrode slitting system and method proposed in this application collects the information of the electrode in real time, corrects the electrode, and realizes an automatic electrode correction closed loop. It reduces the batch scrapping of the electrode and improves the electrode yield and production efficiency. The automatic detection of the slitting system replaces manual detection, reduces labor costs, improves product stability, and ensures personnel safety.

[0064] In the present application, the battery may include a lithium-ion secondary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery or a magnesium-ion battery, etc., and the embodiments of the present application are not limited to this. The core component of the battery that can realize the repeated charge and discharge function is the electrode assembly in the battery cell. The electrode assembly includes a pole piece and a diaphragm, and the pole piece includes a positive pole piece and a negative pole piece. The diaphragm is usually arranged between the positive pole piece and the negative pole piece to insulate the positive pole piece and the negative pole piece from each other. The material of the diaphragm can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc. The battery cell mainly relies on the movement of metal ions between the positive pole piece and the negative pole piece to work.

[0065] Among them, the pole piece includes a current collector and an active material layer. The current collector includes a coated area coated with an active material layer and an empty foil area not coated with an active material layer along the width direction of the pole piece. Pole ears are cut on the current collector in the empty foil area. The pole ears are metal conductors that lead the positive and negative electrodes from the battery cell and are the contact points when the battery is charged and discharged. In production practice, the empty foil area is also called the "pole ear area". The positive electrode current collector can be aluminum foil, and the positive electrode active material layer includes ternary materials, lithium manganese oxide or lithium iron phosphate. The negative electrode current collector can be copper foil, and the negative electrode active material layer includes graphite or silicon.

[0066] Slitting refers to cutting a pole piece into multiple pole pieces along the width direction according to the structure and specifications of the battery design. Generally, for wound batteries, the pole piece is slit into multiple pole pieces according to the design width; for laminated batteries, the pole piece material needs to be slit before being cut into pieces, and then cut into the required size.

[0067] The pole piece slitting system and method of the embodiment of the present application may be performed before or after the die-cutting process. Die-cutting refers to cutting the pole piece in the empty foil area of ​​the pole piece according to the design specifications of the pole piece. Since there is a long tape path between the pole piece slitting and die-cutting processes, in order to ensure the quality of the pole piece slitting, the pole piece needs to be corrected before slitting to correct the pole piece's tape path posture.

[0068] like Figure 1 As shown, the embodiment of the present application provides a pole piece cutting system 1000, including: a pole piece cutting device 200, an information acquisition module 300 and a processor 700. The pole piece cutting device 200 is used to cut the first pole piece 110 into a plurality of second pole pieces 120, wherein the width of the first pole piece 110 is greater than the width of the second pole piece 120. The information acquisition module 300 is used to collect information of the second pole piece 120. The processor 700 is used to obtain information of the second pole piece 120, and determine whether the plurality of second pole pieces 120 are offset according to the information. When an offset occurs, the processor 700 corrects the first pole piece 110.

[0069] The electrode cutting device 200 may be any mechanism capable of realizing the electrode cutting function. Figure 2 As shown, the pole piece cutting device 200 is used to cut the first pole piece 110 into a plurality of second pole pieces 120. In some embodiments, the pole piece cutting device 200 may include a plurality of cutting pieces, and different cutting pieces are used to cut different areas of the pole piece. For example, the plurality of cutting pieces act on the centers of the plurality of empty foil areas or coated areas of the first pole piece 110 to be cut, respectively, to divide the first pole piece 110 into a plurality of second pole pieces 120 of uniform width. At present, the battery pole piece cutting process mainly adopts the following three methods: (1) disc shear cutting; (2) die punching; (3) laser cutting. The edge quality and dimensional data of the pole piece cutting will directly affect the performance and safety of the finished battery. Among them, laser cutting has the characteristics of high production efficiency and good process stability compared with disc shear cutting and die punching, and has been applied to the cutting of battery pole pieces in industry. Accordingly, the cutting piece may include but is not limited to a cutter, a cutting head, a laser beam, etc. The cutting piece is used to perform the above-mentioned cutting operation to complete the stripping of the pole piece. In the embodiment of the present application, for the convenience of distinction, the pole piece before cutting is called the first pole piece 110, and the pole piece after cutting is called the second pole piece 120.

[0070] The information acquisition module 300 is always in the state of collecting information, and can send the collected information to the processor 700 for processing in real time. The information acquisition module 300 includes at least one information acquisition submodule, which is used to collect information of multiple second pole pieces 120. The information acquisition module 300 can collect various characteristic information such as shape, size, position, brightness, color, texture, etc. of the second pole piece 120 in the slitting system 1000. The information acquisition module 300 collects information in the following four ways: (1) Infrared / thermal infrared sensing: using infrared sensors or thermal infrared cameras to capture infrared or thermal infrared images that are invisible to the human eye. (2) Camera capture: using digital cameras or video cameras to capture images by scanning line by line or frame by frame. (3) Video acquisition: by collecting continuous video streams through cameras or cameras, the information of the pole piece can be obtained by extracting image frames from continuous videos. (4) 3D scanning: by using structured light, time of flight (TOF) or stereo cameras and other technologies, the three-dimensional shape and texture information of the object can be obtained. Among them, structured light is a system structure composed of a projector and a camera. After using a projector to project specific light information onto the surface and background of an object, the camera collects information. This solution can calculate the position and depth of the object and other information based on the changes in the light signal caused by the object, and then restore the entire three-dimensional space. TOF technology is a technology that further understands certain properties of particles or media by measuring the time it takes for an object, particle or wave to fly a certain distance in a fixed medium (the medium / distance / time are all known or measurable). A stereo camera refers to a camera that can synchronously photograph to obtain a stereo pair of images. Accordingly, in some embodiments, the information acquisition submodule can be a (thermal) infrared sensor device, a dedicated industrial camera, a digital X-ray imaging device, a video acquisition device, a 3D scanning device, or an ordinary digital camera, a video camera, a mobile phone camera, etc. In an embodiment of the present application, collecting information about the second pole piece 120 refers to obtaining information about the second pole piece 120 through the information acquisition module 300, which includes all required information that can be used for offset judgment of the second pole piece 120, including information such as the shape, size, and position of the second pole piece 120.

[0071] In an embodiment of the present application, the processor 700 may be a central processing unit (CPU) or an application specific integrated circuit (ASIC), which is used to perform a plurality of different signal processing processes. The processor 700 acquires the pole piece information collected by the information acquisition module 300 in real time, including relevant information that can be used to judge the pole piece offset. After different signal processing, the processor 700 outputs the offset judgment result. The processor 700 also outputs a correction instruction to correct the pole piece. Among them, the pole piece offset refers to the pole piece width after cutting compared with the standard width, and the offset exceeds the lower limit of the error threshold, but does not exceed the upper limit of the error threshold. At this time, the pole piece can be corrected to improve the width of the pole piece cut later. The processor 700 is also called an "industrial computer", which is used to display the production status of the equipment and control the equipment to perform corresponding operations, and generally includes a host computer and a slave computer. In concept, the controller and the service provider are the upper computer, and the controlled and the serviced are the lower computer, which can also be understood as the relationship between the host and the slave. The master-slave relationship between the upper computer and the lower computer can be converted. In the embodiment of the present application, after the upper computer obtains the information of the pole piece, it is processed by calculation and sends the corresponding command to the lower computer first. The lower computer then interprets the command into the corresponding timing signal to control the relevant equipment components and drive devices. The lower computer reads the equipment status data (generally analog quantity), converts it into a digital signal and feeds it back to the upper computer. Regarding the upper computer and the lower computer, specifically, the upper computer (Host Computer / Master Computer / UpperComputer) refers to a computer that can directly issue control commands, generally a human-machine interface device (Human Machine Interface) such as a workstation and a touch screen, including hardware and software. In the embodiment of the present application, the screen of the upper computer will display various information of the pole piece obtained, and will also display the processing results of the pole piece information, including the offset results. The slave computer is a computer that directly controls the equipment and obtains the equipment status. It is generally a microcomputer such as a PLC (Programmable Logic Controller) or a single chip microcomputer (Single Chip Microcomputer / Slave Computer / Lower Computer). Among them, PLC is a digital operation controller with a microprocessor for automatic control, which can load control instructions into the memory at any time for storage and execution. PLC consists of functional units such as CPU, instruction and data memory, input / output interface (I / O interface), power supply, analog-to-digital (A / D) conversion, etc., including various functions such as logic control, timing control, analog control, multi-machine communication, etc.A single-chip microcomputer is an integrated circuit chip that uses very large-scale integrated circuit technology to integrate a CPU with data processing capabilities, random access memory (RAM), read-only memory (ROM), multiple I / O interfaces and interrupt systems, timer / counters and other functions (may also include display drive circuits, pulse width modulation circuits, analog multiplexing, A / D conversion and other circuits) into a silicon chip to form a small and complete microcomputer system.

[0072] In the embodiments of the present application, offset refers to the situation where a spatial offset occurs. Specifically, the offset of the second pole piece 120 refers to the situation where the second pole piece 120 is cut off-center, that is, the area cut along its width direction is misaligned, and the accuracy requirement of the cutting cannot be met. If the cutting continues on the basis of the offset, the second pole piece 120 will be scrapped in batches. Not only does it affect the yield rate of the cutting process, but the second pole piece 120 with unqualified dimensional accuracy flows into the subsequent winding or lamination process. If the negative electrode cannot completely wrap the positive electrode, it will affect the performance of the battery, such as the state of charge (SOC) of the battery cell. In some embodiments, the offset of the second pole piece 120 can be understood as the position of the first pole piece 110 is offset relative to the position of the cutter, and the cutter does not cut from the central axis of the cutting area, resulting in the cut pole piece being wide on one side and narrow on the other.

[0073] When it is determined that an offset occurs, the processor 700 corrects the first pole piece 110. In an embodiment of the present application, when it is determined that an offset occurs, and the offset is less than or equal to the upper threshold of the offset error, the processor 700 calculates the offset error as a correction value, and corrects the first pole piece 110 according to the correction value. Correction generally refers to a technical operation taken to keep the sides of the coil neat and consistent during the coil winding process. In an embodiment of the present application, correction refers to an operation in which, after an offset occurs, the position of the first pole piece 110 is adjusted so that the widths of the regions cut along the width direction can remain consistent during slitting. In some embodiments, adjusting the position of the first pole piece 110 includes adjusting its angle, position in the width direction, etc. in the slitting system 1000, and moving the first pole piece 110 so that the cutter position is aligned with the central axis of the cutting position.

[0074] In some embodiments, Figure 3As shown, the slitting system 1000 also includes a correction module 400, which is used to adjust the position of the pole piece according to the control of the processor 700. Accordingly, the processor 700 corrects the first pole piece 110 by controlling the correction module 400 to correct the first pole piece 110. The correction module 400 is used to correct the first pole piece 110 according to the control command of the processor 700. The correction module 400 generally includes a correction mechanism and a motor. The correction mechanism has different specifications according to different strokes and thrusts, and is used to receive the correction instructions of the processor 700, and control the motor to drive the correction mechanism to perform correction operations. In some embodiments, the correction mechanism may include a support frame, a first correction roller and a second correction roller to correct the deviation, so as to keep the shape of the second pole piece 120 after slitting relatively consistent. The shape and manufacturing material of the support frame are not limited. The first correction roller and the second correction roller can be rotatably arranged on the support frame. The first correction roller and the second correction roller are arranged relative to each other, and the pole piece passes through the roller gap between the first correction roller and the second correction roller. The first deflection correction roller and the second deflection correction roller cooperate to clamp the pole piece, and adjust the position of the pole piece in the axial direction of the first deflection correction roller to achieve deflection correction. The first pole piece 110 after deflection correction is then sent to the pole piece cutting device 200 for slitting. Specifically, the first deflection correction roller and the second deflection correction roller are arranged in the conveying direction of the first pole piece 110, and the first pole piece 110 includes a first surface and a second surface that are opposite to each other. The first deflection correction roller and the second deflection correction roller are arranged on both sides of the first pole piece 110, that is, the first deflection correction roller contacts the first surface, and the second deflection correction roller contacts the second surface. The first deflection correction roller and the second deflection correction roller are clamped on the first surface and the second surface of the pole piece, and the position of the first pole piece 110 in the axial direction of the first deflection correction roller is adjusted to calibrate the position of the first pole piece 110 when slitting.

[0075] The pole piece cutting system 1000 proposed in the embodiment of the present application can detect pole piece information in real time during the battery cell pole piece cutting process. Compared with manual correction after manual sampling, it reduces the batch scrapping of pole pieces and improves the yield rate of pole piece cutting. It also reduces production costs such as labor and materials, while reducing the contact between personnel and machines, ensuring personnel safety.

[0076] In some implementations, such as Figure 4 As shown, the information acquisition module 300 includes an image acquisition module 301, which is preferably a charge coupled device camera.

[0077] Among them, the image acquisition module 301 refers to any of the above-mentioned devices that obtain information in the form of images, such as professional industrial cameras, digital cameras, video cameras, mobile phone cameras, etc. As a preferred embodiment, a charge-coupled device camera, namely a CCD (Charge-Coupled Device) camera, can convert light into electric charges and store and transfer the charges. The CCD camera can also take out the stored charges to change the voltage. The CCD camera has the characteristics of high color reproduction accuracy, small size, light weight, no influence of magnetic fields, and anti-vibration and anti-impact, and is widely used in industry. The CCD camera converts the pixel value of the light signal into an electrical signal by scanning the pixel value of each pixel point of the electrode, and converts the electrical signal into a digital signal through analog-to-digital conversion.

[0078] The image acquisition module 301 has both cost and performance advantages compared to other information acquisition systems. The image acquisition technology is highly mature and easy to apply in industry. As a preferred CCD camera, compared to other image acquisition devices, it has the advantages of high imaging quality, low noise, high sensitivity, fast reading, etc., and high detection efficiency and accuracy.

[0079] In some embodiments, Figure 4 As shown, the information acquisition module 300 generally further includes a light source 302 for supplementing light to the image acquisition module 301. By adjusting the position and angle of the image acquisition module 301 and the light source 302 relative to the pole piece and adjusting the brightness of the light source, multiple frames of images to be detected at different positions, different orientations and different exposure rates can be obtained for subsequent detection.

[0080] Optional, such as Figure 5 As shown, the straight line AB passes through the center point B of the first roller 410 and the contact point A between the second pole piece 121 and the first roller 410, and is the center line between the straight line AC from the image acquisition module 301 to the contact point A and the straight line AE from the light source 302 to the contact point A. In other words, the angle between the center line AB and the straight line AB from the image acquisition module 301 to the contact point A is equal to the angle between the center line and the straight line AE from the light source 302 to the contact point A, that is, ∠α. In some embodiments, ∠α can be 30°, and the distance DD from the image acquisition module 301 to the contact point can be 590 mm, which is called the light source distance.

[0081] Selecting the image acquisition module 301 to collect information can not only be used to detect the offset of the pole piece, but also can be used to detect the appearance defects of the pole piece. Therefore, there is no need to set up other measuring devices or image acquisition devices separately, saving costs and system space. The light source 302 is easy to adjust, which can not only make the acquired image clearer, but also obtain multiple frames of image information under different lighting conditions, thereby improving the detection accuracy.

[0082] During the manufacturing process, the pole piece is generally stored and transported in the form of a roll so that it can be coated, cold pressed, slit, and die-cut. To improve production efficiency, the pole piece roll generally includes a plurality of active material coating areas and empty foil areas that are repeatedly arranged in the vertical direction along the pole piece conveying direction, that is, the width direction of the pole piece. As mentioned above, the coating area is the area on the current collector where the active material layer is coated. The empty foil area is the current collector that is not coated with the active material layer.

[0083] Optionally, depending on the cutting position, the film may be cut from the center line of the empty foil area or the coated area. Fig. 6A It is a schematic diagram of obtaining a plurality of second pole pieces 120 by cutting from an empty foil area. Figure 6B Schematic diagram of obtaining a plurality of second pole pieces 120 by cutting from the coating area. Fig. 6A As shown, the second pole piece 120 may include a coating area and empty foil areas on both sides of the coating area along the width direction; or Figure 6B As shown, it may include a hollow foil area and coated areas on both sides of the hollow foil area. The electrode sheet cutting device 200 cuts the electrode sheet from a plurality of hollow foil areas ( Fig. 6A ) or coating area ( Figure 6B ) to obtain a plurality of second pole pieces 120-1, 120-2, 120-3, 120-4 of required specifications. The plurality of second pole pieces 120 are numbered sequentially. After being numbered sequentially, the plurality of second pole pieces 120 are divided into two paths, odd-numbered and even-numbered, and transmitted separately.

[0084] In some embodiments, the slitting system 1000 further includes a plurality of rollers. As transmission components of the slitting system 1000, they are respectively arranged at different positions in the conveying direction. The transmission component is a component or mechanism that transmits power from one part of the machine to another part to make the machine or machine parts move or operate. Due to the friction between the roller and the second pole piece 120, the self-rotation of the roller can drive the second pole piece 120 to rotate, so that the second pole piece 120 is continuously conveyed forward along the conveying direction. In some embodiments, as Figure 2 and Figure 3As shown, the slitting system 1000 includes two rollers, namely a first roller 410 and a second roller 420. Among them, the first roller 410 is used to convey a plurality of odd-numbered second pole pieces after slitting, such as 120-1, 120-3, etc., and the second roller 420 is used to convey a plurality of even-numbered second pole pieces 120-2, 120-4, etc. after slitting. In other embodiments, the number of rollers is the same as the number of second pole pieces 120 after slitting, and each roller only conveys one second pole piece 120 for conveying. The plurality of second pole pieces 120 after slitting are conveyed in two directions, which saves more system space and is easier to design in structure compared to the design of using different rollers to convey each second pole piece 120 in different directions. Each second pole piece 120 is conveyed in different directions using different rollers, which has the advantages of more accurate conveying, etc.

[0085] In some embodiments, Figure 2 and Figure 3 As shown, the information acquisition module 300 includes a first information acquisition submodule 310, which is used to collect information of the odd-numbered second pole pieces 120-1 at the first roller 410. In other embodiments, the information acquisition module 300 also includes a second information acquisition submodule 320, which is used to collect information of the even-numbered second pole pieces 120-2 at the second roller 420. The first information acquisition submodule 310 and the second information acquisition submodule 320 generally include the same information acquisition device.

[0086] Preferably, the first information acquisition submodule 310 and the second information acquisition submodule 320 can be industrial cameras for acquiring information of the second pole piece 120. The industrial camera has the characteristics of high frame rate, comprehensive information acquisition, and high imaging quality. It is suitable for high-quality image processing algorithms and has stable performance. It is easy to install, and the camera structure is compact and strong and not easy to damage. It has a long continuous working time and can be used in harsh environments.

[0087] Preferably, each second pole piece 120 corresponds to an information collection submodule, so that the information of all the cut second pole pieces 120 can be completely collected.

[0088] The information collection module 300 collects information about the pole piece at the roller shaft, rather than collecting information at other positions in the direction of pole piece transmission, because the motion state of the pole piece at the roller shaft is relatively stable, which can improve the quality of information collection.

[0089] In some embodiments, the information of the second pole piece 120 includes the width of the second pole piece 120 , and accordingly, the processor 700 determines the offset including determining whether a width offset occurs, wherein the direction of the width is a direction perpendicular to the transmission direction of the second pole piece 120 .

[0090] In some embodiments, the processor 700 determines whether a width offset occurs by comparing the width of the second pole piece 120 after cutting with the error of the standard width, including: determining the standard width of the second pole piece 120, including the standard empty foil area width and the standard coating area width. Calculating the offset of the width of each second pole piece 120 compared to the standard width. If the width offset is less than or equal to the lower limit threshold of the width offset error, it is determined that the width offset has not occurred. If the width offset is greater than the lower limit threshold of the width offset error, it is determined that the width offset has occurred. Wherein, if Fig. 6A and 6B In the two forms of the second pole piece 120 shown, the standard width refers to the width of the empty foil area or the coating area at any edge of the pole piece selected as the standard width of the pole piece according to the pole piece material. Fig. 6A The second electrode 120 shown in FIG. 1 is cut at the center line of each empty foil area, and the standard width is the standard empty foil area width. Figure 6B The standard width of the second pole piece 120 shown is the standard coating area width. Optionally, when the cutting position is the empty foil area, the lower limit threshold of the width offset error of the empty foil area is 1mm, and the upper limit threshold is 2mm. Optionally, when the cutting position is the coating area, the lower limit threshold of the width offset error of the coating area is 0.5mm, and the upper limit threshold is 1mm.

[0091] Compared with the information of angle offset, width offset is easier to obtain and process. By judging the width offset, it is determined whether correction is needed. It has low complexity and is easy to implement.

[0092] In some embodiments, the slitting system 1000 further includes: when the processor 700 determines that an offset has occurred, it also includes: if the width offset is greater than the upper limit threshold of the width offset error, the processor 700 notifies the alarm 800 to alarm. When the width offset exceeds the upper limit threshold of the width offset error, the partially cut second pole piece 120 is a defective product and needs to be checked and processed by personnel. The slitting system 1000 continues to work after the operator is instructed by the alarm to stop the machine to process the defective products. The processor 700 notifies the alarm 800 to alarm by outputting an alarm instruction. In some embodiments, the alarm 800 may include an alarm indicator light and / or a buzzer. When the alarm 800 alarms, the alarm indicator light flashes and / or the buzzer sounds. The alarm can promptly remind the operator to discover and deal with the width offset problem of the pole piece, reduce the defective rate of the pole piece, and improve production efficiency.

[0093] In addition, in some embodiments, the processor 700 also includes determining whether a coating area is misaligned before determining whether an offset occurs. The processor 700 determines whether a coating area is misaligned by comparing the coating positions of the first surface and the second surface of the first pole piece 110. The distance error from the edge of the coating area of ​​the first surface relative to the edge of the pole piece of the second surface is used as the position offset error. If the position offset error is greater than the misalignment threshold, the width offset judgment is no longer performed. The processor 700 notifies the alarm 800 to shut down the alarm and process the portion of the pole piece. If the coating area position offset error is less than the misalignment threshold, the processor 700 continues to determine the width offset. In some embodiments, for similar Figure 6B The processor 700 further includes determining whether the coating area of ​​each second pole piece 120 after slitting is misaligned. The processor 700 determines whether the coating area of ​​the second pole piece 120 is misaligned, and can refer to the determination of the misalignment of the coating area of ​​the first pole piece 110. Optionally, the misalignment error threshold can be 0.5 mm. Before determining whether the width offset occurs, it is determined whether the coating area is misaligned, and the bad pole piece can be checked and processed in time to reduce the waste of resources of the slitting system 1000.

[0094] like Figure 2 and Figure 3 As shown, in some embodiments, the slitting system 1000 further includes a third roller 430 for conveying the first pole piece 110 , and accordingly, the information acquisition module 300 further includes a third information acquisition submodule 330 for acquiring information of the first pole piece 110 at the third roller 430 .

[0095] The third roller 430 is one of the transmission components of the slitting system 1000 and is consistent with the first roller 410 and the second roller 420. The third information collection submodule 330 is also consistent with other information collection submodules to facilitate processing and manufacturing.

[0096] The purpose of collecting the information of the first pole piece 110 is to detect the appearance defects of the pole piece before deviation correction, to deal with the defective pole piece in time, and to improve the yield rate.

[0097] The pole piece includes a first side and a second side, i.e., a front side and a back side, and each side can detect offset and defects. In some embodiments, preferably, the information of the first side of the first pole piece 110 can be collected by the third information collection submodule 330. The first information collection submodule 310 and the second information collection submodule 320 respectively collect information of the second side of the second pole piece 120. In this way, the information of the first side and the second side of the pole piece can be completely collected, and the system space can be saved, and the number of information collection modules 300 can be reduced.

[0098] Optionally, two information collection submodules may be used to respectively obtain information of the first surface and the second surface of the first pole piece 110 , so that appearance defects of the pole piece can be completely detected before cutting.

[0099] Optionally, more information collection submodules may be used to obtain information about the first surface and the second surface of each second pole piece 120 respectively, and the appearance defects and offsets of the pole pieces may also be completely detected.

[0100] In some embodiments, the information of the first pole piece 110 and / or the second pole piece 120 also includes appearance information. According to the appearance information, the processor 700 is also used to determine whether the first pole piece 110 and / or the plurality of second pole pieces 120 have appearance defects; if appearance defects occur, the alarm 800 is notified to sound an alarm.

[0101] The appearance information refers to the shape, light and dark information of the pole piece, which respectively correspond to different appearance defects. Appearance defects include wrinkles, bumps, breakages, bubble decarburization, coating omissions, metal leakage, dark marks and other defects on the surface of the pole piece. In some embodiments, the shape information corresponds to wrinkles, bumps, breakages, bubble decarburization, coating omissions and other defects, and the light and dark information corresponds to metal leakage, dark marks and other defects.

[0102] In some embodiments, the processor 700 can determine these appearance defects through an image processing algorithm. Optionally, the image processing algorithm can use deep learning technology. Specifically, through a number of image acquisition modules 301 and light sources 302 in different orientations, multiple frames of images to be detected at different positions, different orientations and different exposure rates are obtained. Then, the multiple frames of images to be detected are screened based on the image template of the product to be detected to obtain the target image to be detected containing the product to be detected. When the defect detection starts, the processor 700 receives multiple frames of images to be detected of the pole piece to be detected uploaded by the image set module 301. The target image to be detected is input into a pre-trained defect detection model, wherein the pre-trained defect detection model is trained by a large number of sample image data of various morphological defects, and the defect detection model outputs the detection result, wherein the detection result includes defect data, such as defect type data, defect size data and defect location data. The texture, color, shape and other features of the pole piece surface are usually complex, and the defect forms that appear are also varied. Deep learning technology can learn the abstract features of defects based on the defective sample data of the electrode, thereby accurately detecting the parts of the electrode that are similar in morphology to the defective samples, thereby improving the accuracy and precision of defect detection.

[0103] In some embodiments, after determining that an appearance defect occurs, the processor 700 outputs an appearance defect alarm instruction to notify the alarm 800 to sound an alarm.

[0104] In some embodiments, Figure 3As shown, the slitting system 1000 further includes a marking mechanism 600, which is used to print and paste defect labels on the appearance defects of the first pole piece 110 and / or the second pole piece 120. Specifically, after the processor 700 determines that the first pole piece 110 and / or the second pole piece 120 has an appearance defect, it outputs a labeling signal corresponding to the defect, and controls the marking mechanism 600 to paste the corresponding defect label on the defect position of the first pole piece 110 and / or the second pole piece 120.

[0105] The prior art sets up multiple measuring devices to measure and correct the offset of the pole piece that is divided into two, but does not consider the detection of appearance defects, and cannot simultaneously realize automatic correction and appearance defect detection. The separate detection of offset and defect results in a low system integration, and the detection method is single, which is not suitable for the offset and defect detection of the pole piece that is divided into many. Some embodiments of the present application detect appearance defects in the process of correcting the offset, thereby improving the utilization rate of the information acquisition module 300. Real-time detection of appearance defects, without the need for manual timed sampling, reduces the flow of defective products into subsequent processes, and is beneficial to ensuring battery performance. Timely alarm when defects occur, making it convenient for engineers to troubleshoot and locate the problem.

[0106] like Figure 7 As shown, the present application provides another slitting system 1000. Figure 2 In the slitting system 1000 shown, the transmission assembly in this embodiment includes more rollers for conveying the pole piece coils. For the sake of brevity, the same parts as the previous embodiments are not repeated here.

[0107] Among them, multiple rollers are arranged at different positions in the conveying direction of the slitting system 1000. Multiple rollers are arranged at the position where the electrode sheet roll enters the slitting system, and after unwinding, it is conveyed in the slitting system in the form of the first electrode sheet 110. Multiple rollers are arranged on the conveying path of the second electrode sheet 120 to form an irregular conveying path. A roller is arranged at the end of the conveying path of the second electrode sheet 120, so that the multiple second electrode sheets 120 obtained by slitting can be rolled up.

[0108] The pole piece slitting system 1000 proposed in this embodiment can not only detect offset and appearance defects in real time, but also realize the unwinding and rewinding of pole piece rolls, and improve the stability of pole piece transmission on rollers and space utilization.

[0109] like Figure 8 As shown, the embodiment of the present application also provides a pole piece cutting method, the method comprising:

[0110] S100: cutting the first pole piece 110 into a plurality of second pole pieces 120, wherein the width of the first pole piece 110 is greater than that of the second pole piece 120; S200: collecting information of the second pole piece 120; and S300: acquiring information and executing S400 according to the information: determining whether the second pole piece 120 is offset, and S500: correcting the first pole piece 110 when an offset occurs.

[0111] Judgment is a thinking process that affirms or denies the situation of things. To judge whether the electrode is offset after slitting, that is, to judge whether the cutting is biased, the judgment results include two results: offset occurs and no offset occurs.

[0112] The pole piece cutting method proposed in the embodiment of the present application detects the pole piece offset in real time during the battery cell pole piece cutting process. Compared with manual correction after manual sampling, it reduces the batch scrapping of pole pieces and improves the yield rate of pole piece cutting. It can also reduce production costs such as labor and materials, while reducing the contact between personnel and machines and ensuring personnel safety.

[0113] like Fig. 9 As shown, in some embodiments, the method includes: using two rollers, a first roller 410 and a second roller 420, to perform S210: respectively conveying the odd-numbered second pole pieces 120-1 and the even-numbered second pole pieces 120-2 after slitting.

[0114] Compared with the method of transmitting each second pole piece 120 in a different direction, the plurality of second pole pieces 120 - 1 and 120 - 2 after being cut are transmitted in two directions, which saves more system space and is easier to design in terms of structure.

[0115] like Fig. 9 As shown, in some embodiments, S200 collects information of the second pole piece 120 including:

[0116] S220 : Collecting information of the odd-numbered second pole pieces 120 - 1 at the first roller 410 and information of the even-numbered second pole pieces 120 - 2 at the second roller 420 .

[0117] The information acquisition module 300 is used to acquire information of the second pole piece 120. The information of the second pole piece 120-1 is acquired by the first information acquisition submodule 310, and the information of the second pole piece 120-2 is acquired by the second information acquisition submodule 320. Since the motion state of the pole piece at the roller shaft is relatively stable, the quality of information acquisition can be improved by acquiring information of the pole piece at the roller shaft.

[0118] In some embodiments, the information of the second pole piece 120 includes the width of the second pole piece 120, and accordingly, the offset includes a width offset, wherein the direction of the width is a direction perpendicular to the conveying direction of the second pole piece 120. According to the aforementioned method, by comparing the width of the second pole piece 120 with the standard width, it is determined whether the second pole piece 120 has a width offset. Compared with the information of the angle offset, the width offset is easier to obtain and process, and by determining whether the width offset is required to determine whether the correction is required, the complexity is low and it is easy to implement.

[0119] like Fig. 9 As shown, in some embodiments, the method further includes S230: collecting information of the first pole piece 110. The information of the first pole piece 110 is collected by the third information collection submodule 330. The information of the first pole piece 110 is collected to detect the appearance defects of the pole piece before correction. It is convenient for personnel to deal with defective pole pieces in time and improve the production yield rate.

[0120] like Fig.10 As shown, in some embodiments, the method also includes: the information of the first pole piece 110 and / or the second pole piece 120 also includes appearance information, and S600 is executed according to the appearance information: determining whether the first pole piece 110 and / or the second pole piece 120 has appearance defects; and S700: if appearance defects occur, an alarm is issued.

[0121] Detecting appearance defects during the process of determining the deviation and correcting it is conducive to effective correction. Real-time detection of appearance defects eliminates the need for manual regular sampling, reduces the flow of defective products into subsequent processes, and is conducive to ensuring battery performance.

[0122] In some embodiments, the appearance information includes appearance information of the first surface of the first electrode piece 110 and the second surface of the second electrode piece 120. Preferably, the appearance information of the first surface of the first electrode piece 110 and the appearance information of the second surface of the second electrode piece 120 are included.

[0123] In this way, the information of the first and second surfaces of the electrode piece can be completely collected, and there is no need to collect information of both surfaces of the first electrode piece 110 and each second electrode piece 120, thereby reducing the waste of resources caused by repeated information collection.

Claims

1. A pole piece cutting system (1000), It is characterized in that include: A pole piece cutting device (200) for cutting a first pole piece (110) into a plurality of second pole pieces (120), wherein the width of the first pole piece (110) is greater than that of the second pole piece (120); An information collection module (300) for collecting information of the second pole piece (120); and The processor (700) is used to obtain the information and determine whether the second pole piece (120) is offset according to the information. When an offset occurs, the processor (700) corrects the first pole piece (110).

2. The system (1000) according to claim 1, It is characterized in that The information acquisition module (300) comprises an image acquisition module (301), which is preferably a charge coupled device camera.

3. The system (1000) according to claim 1 or 2, It is characterized in that The system (1000) further comprises a first roller (410) and a second roller (420), wherein the first roller (410) and the second roller (420) are respectively used to convey the odd-numbered second pole pieces (120-1) and the even-numbered second pole pieces (120-2) after slitting.

4. The system (1000) according to claim 3, It is characterized in that The information collection module (300) comprises a first information collection submodule (310) for collecting information of odd-numbered second pole pieces (120-1) at the first roller (410).

5. The system (1000) according to claim 3 or 4, It is characterized in that The information collection module (300) further comprises a second information collection submodule (320) for collecting information of even-numbered second pole pieces (120-2) at the second roller (420).

6. The system (1000) according to any one of claims 1 to 5, It is characterized in that The information of the second pole piece (120) includes the width of the second pole piece (120), and correspondingly, the offset includes a width offset, wherein the direction of the width is a direction perpendicular to the transmission direction of the second pole piece (120).

7. The system (1000) according to any one of claims 1 to 6, It is characterized in that The system (1000) further comprises a third roller (130) for transmitting the first pole piece (110); correspondingly, the information acquisition module (300) further comprises a third information acquisition submodule (330) for acquiring information of the first pole piece (110) at the third roller (130).

8. The system (1000) according to any one of claims 1 to 7, It is characterized in that The information of the first pole piece (110) and / or the second pole piece (120) also includes appearance information, and the processor (700) is further used to determine whether the first pole piece (110) and / or the second pole piece (120) has appearance defects based on the appearance information, and if the appearance defects occur, notify the alarm (800) to sound an alarm.

9. A pole piece cutting method, It is characterized in that The method comprises: Cutting (S100) the first pole piece (110) into a plurality of second pole pieces (120), wherein the width of the first pole piece (110) is greater than that of the second pole piece (120); Collecting (S200) information of the second pole piece (120); and The information is obtained (S300), and it is determined (S400) whether the second pole piece (120) is offset based on the information, and when an offset occurs, the first pole piece (110) is corrected (S500).

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