Defective electrode sheet rejection method, die cutting device, winding device and battery production system

Abstract

The present application relates to a defective electrode sheet rejection method, a die cutting device, a winding device and a battery production system. The defective electrode sheet rejection method comprises the following steps: performing strip splicing trace detection on an electrode sheet material strip having a plurality of continuously distributed electrode sheet units; on the basis of detecting that the electrode sheet material strip has a strip splicing trace, marking two defect identifiers spaced apart by a first preset distance D1 at an upstream position of the strip splicing trace on the electrode sheet material strip; performing defect identifier detection on the electrode sheet material strip during the winding process thereof into an electrode assembly; and on the basis of detecting that the electrode sheet material strip has two defect identifiers, independently winding an electrode sheet unit having the defect identifiers and an adjacent electrode sheet unit located upstream of the electrode sheet unit having the defect identifiers. The defective electrode sheet rejection method in the present application can solve the problem in respect of relatively high loss in electrode sheet material strips, thereby reducing the production cost of batteries and lowering the defect rate of the batteries.

Description

Method for removing defective pole piece, die cutting device, winding device and battery production system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Chinese Patent Application No. 202410467864.8, filed on April 18, 2024, entitled “Method for removing defective pole piece, die cutting device, winding device and battery production system”, which is incorporated by reference in its entirety into this application. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery production, in particular to a method for removing defective pole piece, a die cutting device, a winding device and a battery production system. BACKGROUND

[0004] In the process of battery production, the pole piece needs to be operated in multiple processes, such as coating, cold pressing, die cutting, winding, etc.

[0005] When the pole piece tape is broken in the cold pressing process, the pole piece tape needs to be spliced to make the pole piece tape run normally. Due to the process and operation of cold pressing splicing, there is a thickness abnormal section near the splicing position of the pole piece tape. After the pole piece tape is die cut to form the pole lug, the pole lug is seriously misaligned due to the thickness abnormal section on the pole piece tape, which causes the battery to be scrapped, increases the failure rate of the production line, consumes a large amount of pole piece tape, and increases the production cost of the battery.

[0006] SUMMARY

[0007] The present application aims to at least solve one of the technical problems existing in some cases. To this end, the present application provides a method for removing defective pole piece, a die cutting device, a winding device and a battery production system, which can solve the problem of large loss of pole piece tape, reduce the production cost of the battery, and reduce the failure rate of the battery.

[0008] In a first aspect, the present application provides a method for removing defective pole piece, comprising the following steps:

[0009] Detecting the splicing trace of the pole piece tape with multiple continuously distributed pole piece units;

[0010] Based on detecting that the pole piece tape has a splicing trace, marking two defect identifiers with a first preset interval D1 upstream of the splicing trace of the pole piece tape;

[0011] Detecting the defect identifier of the pole piece tape in the process of winding into an electrode assembly;

[0012] Based on detecting that the pole piece tape has two defect marks, the pole piece unit with the defect marks and the pole piece unit adjacent to and upstream of the pole piece unit with the defect marks are separately wound.

[0013] According to the pole piece bad product rejection method of the first aspect of the present application, at least the following beneficial effects are achieved:

[0014] The pole piece bad product rejection method of the present application detects the splicing trace of the pole piece tape with a plurality of continuously distributed pole piece units, marks two defect marks at a first preset interval apart from each other at a position upstream of the splicing trace of the pole piece tape with the splicing trace, detects the defect marks of the pole piece tape during the winding of the pole piece tape to form an electrode assembly, and then according to the detection that the pole piece tape has two defect marks, the pole piece tape is continuously wound twice according to the length of the pole piece tape required for manufacturing two electrode assemblies, thereby saving the materials of the isolation film, anode / cathode pole pieces required for manufacturing two electrode assemblies, effectively solving the problem of large loss of pole piece tape, reducing the production cost of the battery, and also reducing the defect rate of the battery.

[0015] In some embodiments, during the die cutting of the pole piece tape, a unit mark is marked on at least one of the first and last pole tabs on the pole piece unit.

[0016] In this way, the unit mark can be used to determine the start and end of a single pole piece unit on the pole piece tape during subsequent winding of the electrode assembly, so that the pole piece unit with the defect mark and the pole piece unit adjacent to and upstream of the pole piece unit with the defect mark can be accurately separately wound.

[0017] In some embodiments, the length L0 of the pole piece unit is greater than the first preset interval D1.

[0018] In this way, when the pole piece unit with the defect mark and the pole piece unit adjacent to and upstream of the pole piece unit with the defect mark are separately wound, the two separately wound pole piece units completely contain the splicing trace and the thickness abnormal segment, so that the pole piece unit where the splicing trace is located and the pole piece unit where the thickness abnormal segment is located can be accurately completely rejected and scrapped, the materials of the isolation film, anode / cathode pole pieces required for manufacturing two electrode assemblies are saved, the problem of large loss of pole piece tape is effectively solved, the production cost of the battery is reduced, and the defect rate of the battery is also reduced.

[0019] In some embodiments, the first preset interval D1 satisfies 50mm≤D1≤200mm.

[0020] In this way, when the pole piece unit with the defect mark and the pole piece unit adjacent to the upstream of the pole piece unit with the defect mark are separately wound, the two separately wound pole piece units completely contain the tab trace and the thickness abnormal segment, so that the pole piece unit where the tab trace is located and the pole piece unit where the thickness abnormal segment is located are accurately completely rejected and scrapped, the materials of the isolation film and the anode / cathode pole piece required for manufacturing two electrode assemblies are saved, the problem of large loss of the pole piece material strip is effectively solved, the production cost of the battery is reduced, and the defective rate of the battery is also reduced.

[0021] In some embodiments, the distance between the defect mark close to the tab trace on the pole piece material strip and the tab trace is a second preset distance D2, and the length L0 of the pole piece unit is greater than the second preset distance D2.

[0022] In this way, when the pole piece unit with the defect mark and the pole piece unit adjacent to the upstream of the pole piece unit with the defect mark are separately wound, the two separately wound pole piece units completely contain the tab trace and the thickness abnormal segment, so that the pole piece unit where the tab trace is located and the pole piece unit where the thickness abnormal segment is located are accurately completely rejected and scrapped, the materials of the isolation film and the anode / cathode pole piece required for manufacturing two electrode assemblies are saved, the problem of large loss of the pole piece material strip is effectively solved, the production cost of the battery is reduced, and the defective rate of the battery is also reduced.

[0023] In a second aspect, the present application provides a die cutting device, which comprises:

[0024] A winding unit for pulling the pole piece material strip in a preset direction;

[0025] A die cutting unit for die cutting the pole lug on the pole piece material strip to generate a plurality of continuously distributed pole piece units;

[0026] A tab detection unit for detecting the tab trace of the pole piece material strip;

[0027] A marking unit for marking the defect mark on the pole piece material strip with the tab trace;

[0028] A first control unit in communication connection with the winding unit, the die cutting unit, the tab detection unit and the marking unit;

[0029] When the tab detection unit detects that the pole piece material strip has the tab trace, the marking unit marks two defect marks with a first preset interval D1 upstream of the tab trace;

[0030] And further comprising the following steps,

[0031] detecting the defect marks on the electrode tab material strip during winding into the electrode assembly;

[0032] based on detecting that the electrode tab material strip has two defect marks, separately winding the electrode tab unit with the defect marks and the electrode tab unit adjacent to and upstream of the electrode tab unit with the defect marks.

[0033] The die cutting device according to the second aspect of the present application has at least the following beneficial effects:

[0034] The die cutting device according to the present application marks two continuous defect marks on the electrode tab material strip at a position upstream of the splicing trace during die cutting of the electrode tab material strip, so that subsequent detection of two defect marks on the electrode tab material strip during winding into the electrode assembly is enabled, and based on the detected two defect mark signals, the continuous two electrode tab units corresponding to the electrode tab material strip are separately wound twice, so that the electrode tab unit where the splicing trace is located and the electrode tab unit where the thickness abnormal section is located are accurately completely rejected and scrapped, the materials of the separator, the anode tab and the cathode tab required for manufacturing two electrode assemblies are saved, the problem of large loss of the electrode tab material strip is effectively solved, the production cost of the battery is reduced, and the defective rate of the battery is also reduced.

[0035] In some embodiments, the splicing detection unit is configured as an image collector.

[0036] In this way, the splicing detection unit collects images at each position on the electrode tab material strip without repetition, and sends the collected images to the first control unit, so that the first control unit can control the marking unit to accurately mark two defect marks at a first preset interval D1 apart from each other at a preset position upstream of the splicing trace on the electrode tab material strip based on the image collection signal of the splicing detection unit.

[0037] In a third aspect, the present application provides a winding device, which comprises:

[0038] an anode unwinding unit for unwinding an anode tab;

[0039] a cathode unwinding unit for unwinding a cathode tab;

[0040] a separator unwinding unit for unwinding a separator;

[0041] a winding needle for winding the anode tab and the cathode tab apart by the separator to prepare an electrode assembly;

[0042] a mark detection unit for detecting defect marks on the anode tab when the winding needle winds the anode tab;

[0043] A second control unit is in communication connection with the anode unwinding unit, the cathode unwinding unit, the separator film unwinding unit, the winding needle and the mark detection unit;

[0044] and further comprising the following steps,

[0045] detecting the joint mark of the anode electrode sheet with a plurality of continuously distributed electrode sheet units;

[0046] based on the detection of the joint mark of the anode electrode sheet, marking two defect marks with a first preset interval D1 upstream of the joint mark of the anode electrode sheet;

[0047] wherein, when the mark detection unit detects that the anode electrode sheet has two defect marks with a first preset interval D1, the second control unit controls the winding needle to separately wind the electrode sheet unit with the defect mark and the adjacent electrode sheet unit upstream of the electrode sheet unit with the defect mark, and correspondingly controls the cathode unwinding unit and the separator film unwinding unit to stop unwinding.

[0048] The winding device according to the third aspect of the present application has at least the following beneficial effects:

[0049] The winding device of the present application detects the defect mark of the anode electrode sheet during the winding of the anode electrode sheet to form the electrode assembly, and then according to the detection of the two defect marks of the anode electrode sheet, the anode electrode sheet is wound twice continuously according to the length of the electrode sheet material required for the production of two electrode assemblies, thereby saving the materials of the cathode electrode sheet and the separator film required for the production of two electrode assemblies, effectively solving the problem of large material loss of the corresponding cathode electrode sheet and the separator film, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0050] In a fourth aspect, the present application provides a winding device, which comprises:

[0051] an anode unwinding unit for unwinding an anode electrode sheet;

[0052] a cathode unwinding unit for unwinding a cathode electrode sheet;

[0053] a separator film unwinding unit for unwinding a separator film;

[0054] a winding needle for winding the anode electrode sheet and the cathode electrode sheet with the separator film to prepare an electrode assembly;

[0055] a mark detection unit for detecting the defect mark of the cathode electrode sheet when the winding needle winds the cathode electrode sheet;

[0056] A second control unit is in communication connection with the anode unwinding unit, the cathode unwinding unit, the separator film unwinding unit, the winding needle and the mark detection unit;

[0057] and further comprising the following steps,

[0058] detecting the joint mark on the cathode electrode sheet with a plurality of continuously distributed electrode sheet units;

[0059] based on the detection of the joint mark on the cathode electrode sheet, marking two defect marks with a first preset interval D1 upstream of the joint mark on the cathode electrode sheet;

[0060] wherein, when the mark detection unit detects that the cathode electrode sheet has two defect marks with a first preset interval D1, the second control unit controls the winding needle to separately wind the electrode sheet unit with the defect mark and the adjacent electrode sheet unit upstream of the electrode sheet unit with the defect mark, and correspondingly controls the anode unwinding unit and the separator film unwinding unit to stop unwinding.

[0061] According to the winding device of the fourth aspect of the present application, at least the following beneficial effects are achieved:

[0062] The winding device of the present application detects the defect mark on the cathode electrode sheet during the winding of the cathode electrode sheet to form the electrode assembly, and then according to the detection of the two defect marks on the cathode electrode sheet, the cathode electrode sheet is continuously wound twice according to the length of the electrode sheet material strip required for the production of two electrode assemblies, thereby saving the materials of the anode electrode sheet and the separator film required for the production of two electrode assemblies, effectively solving the problem of large material loss of the corresponding anode electrode sheet and the separator film, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0063] In some embodiments, the mark detection unit is configured as a chromatic aberration sensor.

[0064] In this way, the mark detection unit can accurately detect the two defect marks on the electrode sheet material strip during the winding into the electrode assembly.

[0065] In the fifth aspect, the embodiments of the present application provide a battery production system, which comprises the die cutting device and the winding device.

[0066] According to the battery production system of the fifth aspect of the present application, at least the following beneficial effects are achieved:

[0067] The battery production system of the present application, due to the configuration of the above-mentioned die cutting device and / or winding device, also has the same technical effects as the die cutting device and / or winding device, that is, by detecting the splicing mark of the pole piece tape during the process of die cutting the pole piece tape to produce the pole piece unit with the tab, and marking two defect marks at a first preset interval upstream of the splicing mark of the pole piece tape, and detecting the defect mark of the pole piece tape during the winding process of the pole piece tape to form the electrode assembly, and then according to the detection of the two defect marks of the pole piece tape, the pole piece tape is continuously wound twice according to the length of the pole piece tape required for the production of two electrode assemblies, thereby saving the materials of the isolation film, the anode / cathode pole piece required for the production of two electrode assemblies, effectively solving the problem of large loss of pole piece tape, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0068] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the content of the specification can be implemented, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0069] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to the drawings without creating any creative labor. In the drawings:

[0070] Fig. 1 is a flow chart of the pole piece defect removal method of the embodiments of the present application.

[0071] Fig. 2 is a schematic diagram of the walking of the pole piece tape in the cold pressing process of the embodiments of the present application.

[0072] Fig. 3 is a schematic diagram of the walking of the pole piece tape in the die cutting process of the embodiments of the present application.

[0073] Fig. 4 is a schematic diagram of the structure of the die cutting device of the embodiments of the present application.

[0074] Fig. 5 is a schematic diagram of the walking of the pole piece tape in the winding process of the embodiments of the present application.

[0075] Fig. 6 is a schematic diagram of part of the structure of the winding device of the embodiments of the present application.

[0076] Fig. 7 is another flow chart of the pole piece defect removal method of the embodiments of the present application.

[0077] Fig. 8 is a schematic diagram of the structure of the winding device of the embodiments of the present application.

[0078] Legend: electrode tab material strip 10; tab 11; unit identification 11a; electrode tab unit EA; thickness abnormal section 11b; anode electrode tab 12; cathode electrode tab 13; separator film 14; anode unwinding unit 20; cathode unwinding unit 30; separator film unwinding unit 40; winding needle 50; identification detection unit 60; second control unit 70; cold pressing unit 80; splicing trace M1; defect identification M2; winding unit 100; die cutting unit 200; splicing detection unit 300; marking unit 400; first control unit 500; first unwinding shaft 901; first winding shaft 902; second unwinding shaft 903; second winding shaft 904; third unwinding shaft 905; preset direction S. DETAILED DESCRIPTION

[0079] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0080] The "range" disclosed in the present application is limited in the form of lower limit and upper limit, a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The range limited in this way can include or not include the end value, and can be arbitrarily combined, i.e. any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges of 60-110 and 80-120 are also anticipated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges are all anticipated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "a-b" represents a shorthand notation for any real combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is only a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥2, it is equivalent to disclose that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0081] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0082] All the technical features and optional technical features in the present application can be combined with each other to form new technical solutions, if there is no special description.

[0083] All the steps in the present application can be performed in sequence or randomly, preferably in sequence, if there is no special description. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method can further comprise step (c), which means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0084] The terms “include” and “contain” mentioned in the present application mean open type, and can also mean closed type, if there is no special description. For example, the terms “include” and “contain” can mean that other components not listed can also be included or contained, or only the listed components can be included or contained.

[0085] In the present application, the term “or” is inclusive, if there is no special description. For example, the phrase “A or B” means “A, B, or both A and B”. More specifically, any one of the following conditions satisfies the condition “A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or A and B are both true (or exist).

[0086] In the description of the embodiments of the present application, the term “plurality” means more than two (including two), and similarly, “multiple groups” means more than two groups (including two groups), and “multiple pieces” means more than two pieces (including two pieces).

[0087] In the description of the embodiments of the present application, the technical terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0088] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mount", "connect", "connect", "fix" and other terms should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0089] At present, from the development of market situation, the application of battery is more and more widely. The battery is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment and aerospace and other fields. With the continuous expansion of the application field of battery, the demand of its market is also increasing.

[0090] The battery is composed of one or more battery monomers. For each battery, the plurality of battery monomers that make up it can be connected in series or in parallel or in mixed connection. Among them, mixed connection means that there are series connection and parallel connection in the plurality of battery monomers.

[0091] The battery monomer is the smallest unit of the battery, and in the structure of the battery monomer, it includes the shell, the electrolyte and the electrode assembly. The electrode assembly is the component that electrochemical reaction occurs in the battery monomer, and the electrode assembly includes the positive plate, the negative plate and the separator. The shell can include one or more electrode assemblies, and the electrode assembly is mainly formed by winding or stacking the positive plate and the negative plate, and the separator is usually arranged between the positive plate and the negative plate.

[0092] The shell is a structure with one end opening and hollow inside. The electrode assembly is arranged inside the shell, and the end cover is arranged at the opening of the shell. The end cover is closed to form the internal environment of the battery monomer at the opening. Of course, the end cover and the shell can also be integrated. In some embodiments, the end cover and the shell can form a common connecting surface before other components enter the shell. When it is necessary to seal the inside of the shell, the end cover is closed to the shell. The shell can be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. In some embodiments, the shape of the shell can be determined according to the specific shape and size of the electrode assembly. The material of the shell can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The embodiments of the present application do not make special limitation.

[0093] The battery includes a box body and a plurality of battery monomers arranged in the box body. The battery can be used as a power battery of a new energy vehicle to provide power for the power system of the new energy vehicle.

[0094] In the battery production process, the pole piece needs to be operated in multiple processes, such as pole piece coating, cold pressing, die cutting, winding, etc.

[0095] When the pole piece tape appears a broken tape in the cold pressing process, the pole piece tape needs to be spliced to make the pole piece tape run normally. When the broken pole piece is transported to the splicing station along the running direction, the corresponding cold pressing device needs to be in a stopped state, that is, the pressing roller of the cold pressing device will be separated from the pole piece tape, so as to splice the broken pole piece normally.

[0096] After the splicing of the broken pole piece is completed, the corresponding cold pressing device is restarted again, and the pressing roller of the cold pressing device continues to cold press the pole piece tape. In this process, the stopping and restarting of the cold pressing device will affect the pressure and the duration of the pressure on the pole piece tape, causing a thickness abnormal section near the splicing position of the pole piece tape. After the pole piece tape is die cut to form the tabs, and then wound with the separator film to form the battery cell, the tabs of the battery cell will be severely misaligned due to the thickness abnormal section on the pole piece tape, resulting in the battery cell being scrapped. Not only does this increase the defect rate of the production line, but it also wastes a lot of pole piece tape and increases the production cost of the battery.

[0097] Therefore, in view of the problem of excessive loss of pole piece tape caused by the operation process of splicing the broken pole piece tape in the cold pressing process, one or more embodiments of the present application provide a pole piece defective product rejection method, a die cutting device, a winding device, and a battery production system. In the process of die cutting the pole piece tape to produce pole piece units with tabs, the pole piece tape is detected for splicing marks, and two defect markers spaced apart by a first predetermined distance are marked on the pole piece tape at a position upstream of the splicing mark. In the process of winding the pole piece tape to form an electrode assembly, the pole piece tape is detected for defect markers. Then, according to the detection of two defect markers on the pole piece tape, the pole piece tape is continuously wound twice for two electrode assemblies, thereby saving the materials of the separator film, anode pole piece and cathode pole piece required for manufacturing two electrode assemblies, effectively solving the problem of excessive loss of pole piece tape, reducing the production cost of the battery, and reducing the defect rate of the battery.

[0098] FIG. 1 is a flowchart of a pole piece defective product rejection method according to an embodiment of the present application. As shown in FIG. 1, the pole piece defective product rejection method according to an embodiment of the present application includes the following steps:

[0099] Step S1: detecting splicing marks M1 on a pole piece tape 10 having a plurality of continuously distributed pole piece units EA;

[0100] Step S2: based on the detection of the splicing mark M1 on the pole piece tape 10, marking two defect markers M2 spaced apart by a first predetermined distance D1 at a position upstream of the splicing mark M1 on the pole piece tape 10.

[0101] Step S3, performing defect mark M2 detection on the electrode strip 10 in the process of being wound into an electrode assembly;

[0102] Step S4: Based on the detection of two defect marks M2 on the pole piece strip 10, the pole piece unit EA with the defect mark M2 and the pole piece unit EA located upstream and adjacent to the pole piece unit EA with the defect mark M2 are wound separately.

[0103] The running direction of the pole piece tape when performing a joint mark detection on the pole piece tape is opposite to the running direction of the pole piece tape when performing a defect mark detection on the pole piece tape.

[0104] It should be noted that in step S1, before die-cutting the electrode strip 10, the electrode strip 10 needs to be cold-pressed. Referring to FIG2 , during the cold-pressing process, the first unwinding shaft 901 unwinds the electrode strip 10 to be cold-pressed, and the first reeling shaft 902 reels the cold-pressed electrode strip 10. The electrode strip 10 moves in a back-to-front direction between the first unwinding shaft 901 and the first reeling shaft 902, and the cold-pressing unit 80 performs a cold-pressing treatment at the corresponding position of the electrode strip 10, so that the active material layer on the electrode strip 10 is more tightly bonded to the electrode strip 10.

[0105] It should be noted that, referring to Figure 2, after the pole piece strip 10 is spliced ​​due to broken strips during the cold pressing process, a splicing mark M1 will be formed at the splicing position of the pole piece strip 10. The splicing mark M1 can be understood as the butt joint mark of the two sections of pole piece strips at the butt joint, and its thickness is inconsistent with the thickness of the pole piece strip that has not been spliced. The corresponding visual inspection mechanism can easily detect the splicing mark M1 on the pole piece strip 10.

[0106] After the electrode strip 10 is spliced ​​due to a break in the cold pressing process, a section 11 b with abnormal thickness is generated upstream (behind) the splicing mark M1 on the electrode strip 10 .

[0107] 2 and 3 , after the first winding shaft 902 completely winds up the cold-pressed electrode strip 10, the electrode strip 10 is transferred to the die-cutting station for die-cutting to produce a plurality of continuously distributed electrode units EA on the electrode strip 10. Each electrode unit EA has a plurality of electrode tabs 11 formed thereon. It should be noted that the length of each electrode unit EA corresponds to the material length of the anode electrode sheet or cathode electrode sheet required to produce a single battery cell, that is, one EA length.

[0108] Referring to FIGS. 3 and 4, in the die cutting process, the second unwinding shaft 903 unwinds the pole piece tape 10 to be die cut, and the second winding shaft 904 winds the die cut pole piece tape 10. The pole piece tape 10 moves between the second unwinding shaft 903 and the second winding shaft 904 in a rear-to-front direction, and is subjected to die cutting treatment at the corresponding positions of the pole piece tape 10 by the die cutting unit 200 to generate a plurality of continuously distributed pole piece units EA on the pole piece tape 10, each of which is formed with a plurality of pole tabs 11.

[0109] It can be understood that, in the die cutting process, the thickness abnormal section 11b on the pole piece tape 10 is located downstream of the splicing trace M1, and is first die cut and wound by the second winding shaft 904. The splicing trace M1 on the pole piece tape 10 is wound by the second winding shaft 904.

[0110] During the forward movement of the pole piece tape 10, the splicing trace M1 on the pole piece tape 10 can be detected by the splicing detection unit 300, which can be configured as a visual detection mechanism such as a CCD camera to detect whether the splicing trace M1 exists on the pole piece tape 10.

[0111] In step S2, based on the detection that the pole piece tape 10 has the splicing trace M1, two defect marks M2 spaced apart by a first preset distance D1 can be marked on the pole piece tape 10 upstream of the splicing trace M1 by the marking unit 400. The first preset distance D1 can be controlled according to the material length of the anode or cathode pole piece required for the actual production of a single cell.

[0112] The marking unit 400, the splicing detection unit 300, and the die cutting unit 200 are in communication connection with the first control unit 500 in the background. The marking unit 400 can be a device for marking the defect mark M2 on the pole piece tape 10 with the splicing trace M1 based on various marking methods including visual marking, without limitation. The defect mark M2 can be, but is not limited to, a color mark such as a yellow mark, a green mark, or a red mark.

[0113] Referring to FIGS. 3 and 4, it can be understood that, in the die cutting process, since the thickness abnormal section 11b on the pole piece tape 10 is located downstream of the two defect marks M2, the pole piece units EA where the two defect marks M2 are located on the pole piece tape 10 are wound by the second winding shaft 904.

[0114] After the second winding shaft 904 completely winds the pole piece tape 10 subjected to die cutting and marking, the pole piece tape 10 is transferred to a winding station for winding treatment to be wound together with the separator film, the anode or cathode pole piece to form an electrode assembly.

[0115] (see FIG. 8)

[0116] It should be noted that the pole piece tape 10 of the present application can be used as an anode pole piece or a cathode pole piece required for manufacturing an electrode assembly. When the pole piece tape 10 is an anode pole piece, the pole piece tape 10 is co-wound with a separator film and a cathode pole piece at the winding station to form an electrode assembly. When the pole piece tape 10 is a cathode pole piece, the pole piece tape 10 is co-wound with a separator film and an anode pole piece at the winding station to form an electrode assembly. The electrode assembly can be understood as a single battery cell.

[0117] In step S3, referring to FIGS. 5 and 6, during the winding process, the third unwinding shaft 905 unwinds the pole piece tape 10 that has been die-cut and marked. At the same time, a fourth unwinding shaft (not shown in the figure, see the winding device shown in FIG. 8) synchronously unwinds the anode pole piece / cathode pole piece to be wound, and a fifth unwinding shaft (not shown in the figure, see the winding device shown in FIG. 8) synchronously unwinds the separator film to be wound. The winding needle 50 separates and winds the pole piece tape 10, the anode pole piece / cathode pole piece, and the separator film to prepare an electrode assembly. It should be understood that the winding needle 50 winds to prepare an electrode assembly every time, and the pole piece tape 10 corresponds to the consumption of the length of one pole piece unit EA, and at the same time, the anode pole piece / cathode pole piece and the separator film correspond to the consumption of the length of one pole piece unit EA.

[0118] It is not difficult to understand that, referring to FIGS. 5 and 6, in step S3, during the winding process, the third unwinding shaft 905 unwinds the pole piece tape 10 that has been die-cut and marked, and the winding needle 50 winds the pole piece tape 10, the anode pole piece / cathode pole piece, and the separator film to form an electrode assembly. The pole piece tape 10 moves in the rear-to-front direction between the third unwinding shaft 905 and the winding needle 50. During this process, the pole piece tape 10 can be detected by the defect mark M2 by the mark detection unit 60. The mark detection unit 60 can be configured as a color difference sensor according to the color mark of the defect mark M2.

[0119] The mark detection unit 60, the winding needle 50, the third unwinding shaft 905, the fourth unwinding shaft, and the fifth unwinding shaft are all in communication connection with the second control unit 70 in the background.

[0120] It is easy to understand that, referring to FIGS. 5 and 6, the pole piece units EA where the two defect marks M2 on the pole piece tape 10 are located are unwound before the joining trace M1 and the thickness abnormal segment 11b. That is, the mark detection unit 60 can detect the two defect marks M2 before the thickness abnormal segment 11b on the pole piece tape 10 passes.

[0121] When the mark detection unit 60 detects the two defect marks M2 on the pole piece tape 10, the mark detection unit 60 transmits a detection signal to the second control unit 70. At this time, the pole piece units EA located downstream of the two defect marks M2 are still normally wound.

[0122] When the first electrode sheet unit EA with the defect mark M2 on the electrode sheet tape 10 moves to the position of the winding needle 50, the second control unit 70 controls the fourth unwinding shaft to stop unwinding the corresponding anode / cathode electrode sheet and controls the fifth unwinding shaft to stop unwinding the corresponding separator film, that is, to stop the material supply of the corresponding anode / cathode electrode sheet and the separator film. At this time, the winding needle 50 starts to separately wind the two continuous electrode sheet units EA on the electrode sheet tape 10, that is, to separately wind the electrode sheet unit EA with the defect mark M2 and the electrode sheet unit EA adjacent to the upstream of the electrode sheet unit EA with the defect mark M2 in step S4.

[0123] It should be noted that after the winding needle 50 winds to prepare an electrode assembly, a corresponding cutter unit is arranged on the production line to cut off the prepared electrode assembly. When the cutter unit cuts off the electrode assembly, the cutter unit cuts off the connection between the electrode sheet tape 10, the anode / cathode electrode sheet and the separator film and the winding needle 50 at the corresponding position of the winding needle 50. At the same time, a corresponding feeding unit is arranged on the production line to feed the cut electrode sheet tape 10, anode / cathode electrode sheet and separator film to the winding needle 50 to be connected with the winding needle 50. The cutter unit and the feeding unit are about 100 millimeters (mm) away from the winding needle 50, which will not interfere with the normal winding of the winding needle 50.

[0124] Based on the above description, it can be understood that when the fourth unwinding shaft stops unwinding the corresponding anode / cathode electrode sheet and the fifth unwinding shaft stops unwinding the corresponding separator film, the anode / cathode electrode sheet and the separator film are in a disconnected state with the winding needle 50. When the winding needle 50 separately winds the two continuous electrode sheet units EA on the electrode sheet tape 10, the winding needle 50 will not pull or wind the anode / cathode electrode sheet and the separator film.

[0125] It should be noted that in some embodiments of the present application, the length of one electrode sheet unit EA is L0, the distance between two defect marks M2 is a first preset distance D1, the distance between the defect mark M2 close to the splicing trace M1 on the electrode sheet tape 10 and the splicing trace M1 is a second preset distance D2, and the length of the thickness abnormal section 11b generated by the splicing of the broken tape in the cold pressing process is L1. L0, D1, D2 and L1 satisfy the following relationship: L0>L1+D1+D2.

[0126] In this way, when the pole piece unit EA with the defect mark M2 and the pole piece unit EA adjacent to the pole piece unit EA with the defect mark M2 and located upstream of the pole piece unit EA with the defect mark M2 are separately wound, the two pole piece units EA separately wound include the pole piece segment where the joint trace M1 is located and the pole piece segment where the thickness abnormal segment 11b is located. In this way, the pole piece unit EA where the joint trace M1 is located and the pole piece unit EA where the thickness abnormal segment 11b is located are completely discarded and scrapped, the materials of the separator, the anode pole piece and the cathode pole piece required for manufacturing two electrode assemblies are saved, the problem of large loss of the pole piece material strip is effectively solved, the production cost of the battery is reduced, and the defect rate of the battery is also reduced.

[0127] In some embodiments of the present application, on the pole piece material strip 10, the length of one pole piece unit EA is L0, 5 meters (m)≤L0≤25 meters (m), for example, L0 is 5 m, 9.8 m, 12.4 m or 25 m; the first preset interval between two defect marks M2 is D1, 50 mm≤D1≤200 mm, for example, D1 is 50 mm, 60 mm, 80 mm, 100 mm or 200 mm. It can be understood that the length L0 of the pole piece unit is greater than the first preset interval D1, or it can be understood that the interval between the two defect marks M2 is much smaller than the length of one pole piece unit EA.

[0128] Moreover, in some embodiments, the distance between the defect mark M2 close to the joint trace M1 on the pole piece material strip 10 and the joint trace M1 is a second preset distance D2, the second preset distance D2 is substantially equal to the first preset interval D1, 50 mm≤D2≤200 mm, for example, D2 is 50 mm, 60 mm, 80 mm, 100 mm or 200 mm. It can be understood that the length L0 of the pole piece unit is greater than the second preset distance D2, or it can be understood that the distance between the defect mark M2 close to the joint trace M1 on the pole piece material strip 10 and the joint trace M1 is much smaller than the length of one pole piece unit EA.

[0129] Referring to FIGS. 4, 5 and 6, in the direction of winding and conveying the pole piece material strip 10, the defect mark M2 at the front end (downstream) is the first defect mark M2, and the defect mark M2 at the rear end (upstream) is the second defect mark M2. The distance between the first defect mark M2 and the joint trace M1 is greater than or equal to 100 mm and less than or equal to 400 mm, which is also much smaller than the length L0 of one pole piece unit EA. In addition, it also needs to be explained that in the embodiments of the present application, the length of the thickness abnormal segment 11b generated by the joint of the pole piece material strip 10 in the cold pressing process is L1, 3 m≤L1≤4 m, for example, 3 m, 3.3 m, 3.6 m or 4 m. Of course, in other embodiments, 0<L1≤10 m, for example, L1 is 5 m, 6 m or 10 m.

[0130] It can be understood that when the length of the thickness abnormal section L1, the first preset distance D1 between the two defect marks M2, the length L0 of one pole piece unit EA, the second preset distance D2 between the defect mark M2 close to the taping trace M1 on the pole piece tape 10 and the taping trace M1, and the length L1 of the thickness abnormal section 11b meet the above-mentioned corresponding length range, L0, D1, D2 and L1 meet the following relationship: L0>L1+D1+D2.

[0131] In this way, regardless of whether the two defect marks M2, the taping trace M1 and the thickness abnormal section 11b are located on the same pole piece unit EA or on different pole piece units EA, the lengths of the two defect marks M2, the taping trace M1 and the thickness abnormal section 11b are definitely less than the length L0 of the two pole piece units EA, so that when the pole piece unit EA with the defect mark M2 and the pole piece unit EA adjacent to the upstream of the pole piece unit EA with the defect mark M2 are separately wound in step S4, the two separately wound pole piece units EA completely cover the taping trace M1 and the thickness abnormal section 11b, so as to accurately discard the pole piece unit EA where the taping trace M1 is located and the pole piece unit EA where the thickness abnormal section 11b is located, save the materials of the isolation film, the anode / cathode pole piece required for manufacturing two electrode assemblies, effectively solve the problem of large loss of the pole piece tape, reduce the production cost of the battery, and also reduce the defect rate of the battery.

[0132] It should be further pointed out that in step S2, by marking two continuous defect marks M2 at the upstream position of the taping trace M1 of the pole piece tape 10, the subsequent corresponding second control unit 70 can perform continuous twice separate winding on the corresponding two continuous pole piece units EA of the pole piece tape 10 based on the detected two defect mark M2 signals, so as to simplify the adjustment of the corresponding control logic of the second control unit 70 in the background, and also will not affect the logical detection of the remaining defects (such as wrinkles, concave-convex points, pinholes, and ragged edges) on the pole piece tape 10 during the winding of the electrode assembly.

[0133] It is not difficult to understand that the method for rejecting defective pole pieces of the present application detects the pole piece strip 10 for the joint mark M1 during the process of die-cutting the pole piece strip 10 to produce the pole piece unit EA with the pole ear, and marks the pole piece strip 10 with two defect marks M2 at a first preset distance upstream of the joint mark M1 of the pole piece strip 10, and then detects the defect mark M2 on the pole piece strip 10 during the process of winding the pole piece strip 10 to form an electrode assembly, and then, based on the detection of the two defect marks M2 on the pole piece strip 10, the pole piece strip 10 is rolled twice in succession according to the length of the pole piece strip required to make two electrode assemblies, thereby saving the isolation film and the anode pole piece / cathode pole piece materials required to make the two electrode assemblies, effectively solving the problem of large loss of the pole piece strip 10, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0134] In some embodiments of the present application, referring again to FIG. 3 , FIG. 4 and FIG. 7 , the following steps are further included:

[0135] S11 . During the die-cutting process of the electrode strip 10 , a unit identification 11 a is marked on at least one of the first electrode tab 11 and the last electrode tab 11 on the electrode unit EA.

[0136] In some embodiments, referring to Figures 3 and 4, a marking hole can be die-cut on the first pole ear 11 and the last pole ear 11 on the pole piece unit EA by the die-cutting unit 200. The marking hole is the unit identification 11a. The unit identification 11a can be used to determine the start and end of a single pole piece unit EA on the pole piece strip 10 in the subsequent winding process of the electrode assembly, so that the pole piece unit EA with the defect identification M2 and the pole piece unit EA located upstream and adjacent to the pole piece unit EA with the defect identification M2 can be accurately wound separately.

[0137] It should be noted that in step S3, when the pole piece strip 10 is subjected to defect identification M2 detection by the identification detection unit 60, the identification detection unit 60 can also detect the unit identification 11a on the pole piece strip 10. At the same time, the identification detection unit 60 is provided with an encoder, and the identification detection unit 60 can count or record the length of the pole piece units EA passing through.

[0138] In this way, when the pole piece unit EA with the defect mark M2 moves to the winding needle 50, the second control unit 70 in the background can accurately position the pole piece unit EA with the defect mark M2 based on the encoding signal of the mark detection unit 60, so as to accurately perform the separate winding of the corresponding two continuous pole piece units EA of the pole piece tape 10 twice in succession. In this way, the adjustment of the corresponding control logic of the second control unit 70 in the background can be simplified, and the logical detection of the remaining defects (such as wrinkles, concave-convex points, pinholes, and ragged edges) on the pole piece tape 10 during the winding of the electrode assembly will not be affected.

[0139] In addition, referring to FIGS. 3 and 4, the embodiment of the present application further provides a die-cutting device, which comprises a winding unit 100, a die-cutting unit 200, a tape joint detection unit 300, a marking unit 400, and a first control unit 500.

[0140] The winding unit 100 is used to pull the pole piece tape 10 in a preset direction S. The die-cutting unit 200 is used to die-cut the tabs 11 on the pole piece tape 10 to generate a plurality of continuously distributed pole piece units EA. The tape joint detection unit 300 is used to detect the tape joint mark M1 on the pole piece tape 10. The marking unit 400 is used to mark the defect mark M2 on the pole piece tape 10 with the tape joint mark M1. The first control unit 500 is in communication connection with the winding unit 100, the die-cutting unit 200, the tape joint detection unit 300, and the marking unit 400.

[0141] When the tape joint detection unit 300 detects that the pole piece tape 10 has the tape joint mark M1, the marking unit 400 marks two defect marks M2 at a first preset interval D1 upstream of the tape joint mark M1 on the pole piece tape 10.

[0142] and further comprises the following steps: detecting the defect mark M2 on the pole piece tape 10 in the process of winding into an electrode assembly; and based on the detection that the pole piece tape 10 has two defect marks M2, separately winding the pole piece unit EA with the defect mark M2 and the pole piece unit EA adjacent to the upstream of the pole piece unit EA with the defect mark M2.

[0143] In some embodiments, the die-cutting unit 200, the tape joint detection unit 300, the marking unit 400, and the winding unit 100 are sequentially arranged along the direction in which the pole piece tape 10 is pulled.

[0144] The winding unit 100 can be understood as a winding shaft in the process of die-cutting the pole piece tape 10, that is, corresponding to the second winding shaft 904 in the foregoing (as shown in FIGS. 3 and 4).

[0145] The die-cutting unit 200 is a conventional device capable of cutting and slitting the battery pole piece.

[0146] The tape detection unit 300 can be an image collector, such as a CCD camera. An encoder is arranged on the tape detection unit 300, so that the tape detection unit 300 can record the running time or length of the electrode tab tape 10 at the time point of the detected tape mark M1, to enable the downstream marking unit 400 to accurately position the mark of the two defect marks M2 at the preset positions of the electrode tab tape 10 close to the tape mark M1.

[0147] The marking unit 400 can be a device for marking the defect marks M2 on the electrode tab tape 10 where the tape mark M1 exists, based on various marking methods including visual marks, without limitation. The defect marks M2 can be, but are not limited to, color marks such as yellow marks, green marks, red marks, etc.

[0148] The first control unit 500 can be an integrated circuit chip with signal processing capability.

[0149] It can be understood that, after the tape detection unit 300 detects the presence of the tape mark M1 on the electrode tab tape 10, the electrode tab tape 10 continues to run forward, and the first control unit 500 controls the marking unit 400 to mark the two defect marks M2 at a first preset interval D1 at the preset position upstream of the tape mark M1 on the electrode tab tape 10.

[0150] It can be understood that, the die-cutting device of the present application marks two continuous defect marks M2 at the upstream position of the tape mark M1 on the electrode tab tape 10 during the die-cutting process of the electrode tab tape 10, so that the subsequent double defect mark M2 detection can be performed on the electrode tab tape 10 during the winding into an electrode assembly, and based on the detected two defect mark M2 signals, the corresponding two continuous electrode tab units EA of the electrode tab tape 10 are individually wound twice, so as to accurately completely reject and scrap the electrode tab unit EA where the tape mark M1 is located and the electrode tab unit EA where the thickness abnormal segment 11b is located, save the materials of the isolation film, the anode / cathode electrode tab required for manufacturing two electrode assemblies, effectively solve the problem of large loss of electrode tab tape, reduce the production cost of the battery, and also reduce the defect rate of the battery.

[0151] In some embodiments, in the die-cutting device of the present application, the tape detection unit 300 is configured as an image collector.

[0152] The image acquisition unit 300 acquires images at each position on the non-repeating electrode tab material belt 10 and sends the acquired images to the first control unit 500, so that the first control unit 500 can control the marking unit 400 to accurately mark two defect marks M2 at a first preset interval D1 upstream of the splicing trace M1 based on the image acquisition signal of the image acquisition unit 300.

[0153] In some embodiments, referring to FIGS. 5, 6 and 8, the application also provides a winding device, which comprises an anode unwinding unit 20, a cathode unwinding unit 30, a separator unwinding unit 40, a winding needle 50, a mark detection unit 60 and a second control unit 70.

[0154] The anode unwinding unit 20 is used to unwind the anode tab 12. The cathode unwinding unit 30 is used to unwind the cathode tab 13. The separator unwinding unit 40 is used to unwind the separator 14. The winding needle 50 is used to wind the anode tab 12 and the cathode tab 13 with the separator 14 therebetween to prepare an electrode assembly. The mark detection unit 60 is used to detect the defect mark M2 on the anode tab 12 when the winding needle 50 winds the anode tab 12.

[0155] The second control unit 70 is in communication connection with the anode unwinding unit 20, the cathode unwinding unit 30, the separator unwinding unit 40, the winding needle 50 and the mark detection unit 60.

[0156] and further comprising the following steps: detecting the splicing trace M1 on the anode tab 12 having a plurality of continuously distributed tab units; based on the detection that the anode tab 12 has the splicing trace M1, marking two defect marks M2 at a first preset interval D1 upstream of the splicing trace M1 on the anode tab 12.

[0157] When the mark detection unit 60 detects that the anode tab 12 has two defect marks M2 at a first preset interval D1, the second control unit 70 controls the winding needle 50 to separately wind the tab unit EA having the defect mark M2 and the tab unit EA adjacent to and upstream of the tab unit EA having the defect mark M2, and correspondingly controls the cathode unwinding unit 30 and the separator unwinding unit 40 to stop unwinding.

[0158] It should be noted that the anode unwinding unit 20, the cathode unwinding unit 30 and the separator unwinding unit 40 are all conventional material belt unwinding shafts on a battery production line.

[0159] The winding needle 50 is a conventional winding shaft used to wind an anode tab, a cathode tab and a separator into an electrode assembly in a preset manner.

[0160] The identification detection unit 60 can be configured as a corresponding sensor according to the type of the defect identification M2. For example, the identification detection unit 60 is configured as a color difference sensor based on the defect identification M2 being a color identification.

[0161] The second control unit 70 can be an integrated circuit chip with signal processing capability.

[0162] In addition, it should be noted that a mark hole can be punched on the first tab 11 and the last tab 11 on the pole piece unit EA by the punching unit 200, which is the unit identification 11a. The unit identification 11a can be used to determine the start and end of the single pole piece unit EA on the anode pole piece 12 during subsequent winding of the electrode assembly, so that the pole piece unit EA with the defect identification M2 and the pole piece unit EA adjacent to the upstream of the pole piece unit EA with the defect identification M2 can be accurately wound separately.

[0163] It should be noted that when the identification detection unit 60 detects the defect identification M2 on the anode pole piece 12, the identification detection unit 60 can also detect the unit identification 11a on the anode pole piece 12. The identification detection unit 60 is provided with an encoder, and the identification detection unit 60 can count or record the length of the passing pole piece unit EA.

[0164] In this way, when the pole piece unit EA with the defect identification M2 moves to the winding needle 50, the second control unit 70 can accurately position the pole piece unit EA with the defect identification M2 based on the encoding signal of the identification detection unit 60, so as to accurately separately wind the corresponding two continuous pole piece units EA of the anode pole piece 12 twice. In this way, the adjustment of the corresponding control logic of the second control unit 70 in the background can be simplified, and the logical detection of the remaining defects (such as wrinkles, concave-convex points, pinholes, and ragged edges) on the anode pole piece 12 during winding of the electrode assembly will not be affected.

[0165] It should be noted that after the winding needle 50 winds to prepare an electrode assembly, a corresponding cutter unit is provided on the production line to cut off the prepared electrode assembly. When the cutter unit cuts off the electrode assembly, the connection between the anode pole piece 12, the cathode pole piece 13, and the separator film 14 and the winding needle 50 will be cut off at the corresponding position of the winding needle 50. At the same time, a corresponding feeding unit is provided on the production line to feed the cut anode pole piece 12, cathode pole piece 13, and separator film 14 to the winding needle 50 for connection. The cutter unit and the feeding unit are about 100 mm away from the winding needle 50, which will not interfere with the normal winding of the winding needle 50.

[0166] Based on the above description, it can be understood that when the cathode unwinding unit 30 and the separator unwinding unit 40 stop unwinding the corresponding cathode and separator, the cathode and the separator are in a state of being disconnected from the winding needle 50, and when the winding needle 50 winds the two continuous electrode units EA on the anode electrode 12, the winding needle 50 will not pull or wind the cathode and the separator.

[0167] It can be understood that the winding device of the present application detects the defect mark M2 on the anode electrode 12 during the winding of the anode electrode 12 to form the electrode assembly, and then according to the detection of the presence of two defect marks M2 on the anode electrode 12, the anode electrode 12 is wound twice continuously according to the length of the electrode strip required for the production of two electrode assemblies, thereby saving the materials of the cathode and the separator required for the production of two electrode assemblies, effectively solving the problem of large material loss of the corresponding cathode and the separator, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0168] In addition, referring to FIGS. 5, 6 and 8, the present application also provides a winding device, which comprises an anode unwinding unit 20, a cathode unwinding unit 30, a separator unwinding unit 40, a winding needle 50, a mark detection unit 60 and a second control unit 70.

[0169] The anode unwinding unit 20 is used to unwind the anode electrode 12. The cathode unwinding unit 30 is used to unwind the cathode electrode 13. The separator unwinding unit 40 is used to unwind the separator 14. The winding needle 50 is used to wind the anode electrode 12 and the cathode electrode 13 with the separator 14 to prepare the electrode assembly. The mark detection unit 60 is used to detect the defect mark M2 on the anode electrode 12 when the winding needle 50 winds the anode electrode 12.

[0170] The second control unit 70 is in communication connection with the anode unwinding unit 20, the cathode unwinding unit 30, the separator unwinding unit 40, the winding needle 50 and the mark detection unit 60.

[0171] And further comprising the following steps: detecting the joint mark M1 on the cathode electrode 13 with a plurality of continuously distributed electrode units; based on the detection of the presence of the joint mark M1 on the cathode electrode 13, marking two defect marks M2 with a first preset interval D1 upstream of the joint mark M1 on the cathode electrode 13.

[0172] When the identification detection unit 60 detects that the cathode tab 13 has two defect identifiers M2 at a first preset interval D1 apart, the second control unit 70 controls the winding needle 50 to separately wind the tab unit EA having the defect identifier M2 and the tab unit EA adjacent to and upstream of the tab unit EA having the defect identifier M2, and correspondingly controls the anode unwinding unit 20 and the separator film unwinding unit 40 to stop unwinding.

[0173] In some embodiments, the die-cutting unit 200, the joint detection unit 300, the marking unit 400, and the winding unit 100 are sequentially arranged along the walking direction of the tab material belt 10. The winding device can be provided with the die-cutting device of any of the above embodiments.

[0174] As can be understood, consistent with the working principle of the foregoing winding device, the winding device of the present application detects the defect identifier M2 of the cathode tab 13 during the winding of the cathode tab 13 to form the electrode assembly, and then continuously winds the cathode tab 13 twice according to the length of the tab material belt required for the production of two electrode assemblies, thereby saving the materials of the anode tab and the separator film required for the production of two electrode assemblies, effectively solving the problem of large material loss of the corresponding anode tab and the separator film, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0175] In some embodiments, the present application also provides a battery production system, which comprises the die-cutting device of any of the above embodiments and the winding device of any of the above embodiments.

[0176] Obviously, the battery production system of the present application, due to the configuration of the above-mentioned die-cutting device and winding device, also has the same technical effects as the die-cutting device and winding device, that is, by detecting the joint mark M1 of the tab material belt 10 during the die-cutting of the tab material belt 10 to produce the tab unit EA with the tab lug, and marking two defect identifiers M2 at a first preset interval upstream of the joint mark M1 of the tab material belt 10, and then detecting the defect identifier M2 of the tab material belt 10 during the winding of the tab material belt 10 to form the electrode assembly, and then continuously winding the tab material belt 10 twice according to the length of the tab material belt required for the production of two electrode assemblies, thereby saving the materials of the separator film, the anode tab / cathode tab required for the production of two electrode assemblies, effectively solving the problem of large material loss of the tab material belt 10, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0177] Referring to FIGS. 1-8, one or more embodiments of the present application provide a tab bad product rejection method, a die-cutting device, a winding device, and a battery production system.

[0178] The tab bad product rejection method comprises the following steps:

[0179] Step S1, detecting a splicing mark M1 on a tab material tape 10 having a plurality of continuously distributed tab units EA;

[0180] Step S2, based on detecting that the tab material tape 10 has the splicing mark M1, marking two defect marks M2 at a first preset interval D1 upstream of the splicing mark M1 on the tab material tape 10;

[0181] Step S3, detecting the defect marks M2 on the tab material tape 10 in a process of winding into an electrode assembly;

[0182] Step S4, based on detecting that the tab material tape 10 has two defect marks M2, separately winding the tab unit EA having the defect mark M2 and the tab unit EA adjacent to and upstream of the tab unit EA having the defect mark M2.

[0183] The tab bad product rejection method of the present application detects the splicing mark M1 on the tab material tape 10 in a process of die-cutting the tab material tape 10 to produce tab units EA having tabs, marks two defect marks M2 at a first preset interval upstream of the splicing mark M1 on the tab material tape 10 having the splicing mark M1, detects the defect marks M2 on the tab material tape 10 in a process of winding the tab material tape 10 to form an electrode assembly, and then according to detecting that the tab material tape 10 has two defect marks M2, continuously winds the tab material tape 10 twice according to the length of the tab material tape required for producing two electrode assemblies, thereby saving the materials of the separator and the anode / cathode tab required for producing two electrode assemblies, effectively solving the problem of large loss of the tab material tape 10, reducing the production cost of the battery, and also reducing the defective rate of the battery.

[0184] The die cutting device of the present application, by marking two consecutive defect marks M2 on the upstream position of the tab material belt 10 located at the tab connecting trace M1 during the process of die cutting the tab material belt 10, enables the subsequent detection of the two defect marks M2 on the tab material belt 10 during the winding into electrode assemblies, and based on the detection of the two defect marks M2 signals, the continuous two-time single winding of the corresponding two consecutive tab unit EAs of the tab material belt 10, so as to accurately completely eliminate the tab unit EA where the tab connecting trace M1 is located and the tab unit EA where the thickness abnormal segment 11b is located, save the materials of the separator, anode / cathode tab required for making two electrode assemblies, effectively solve the problem of large loss of tab material belt, reduce the production cost of the battery, and also reduce the defective rate of the battery.

[0185] The winding device of the present application, by detecting the defect mark M2 on the anode / cathode tab 12 / 13 during the process of winding the anode / cathode tab 12 / 13 to form an electrode assembly, and then according to the detection of two defect marks M2 on the anode / cathode tab 12 / 13, the continuous two-time single winding of the anode / cathode tab 12 / 13 according to the length of the tab material belt required for making two electrode assemblies, so as to save the materials of the cathode / anode tab 12 / 13 and the separator required for making two electrode assemblies, effectively solve the problem of large loss of the corresponding cathode / anode tab 12 / 13 and the separator material, reduce the production cost of the battery, and also reduce the defective rate of the battery.

[0186] The battery production system of the present application, since the above-mentioned die cutting device and / or winding device are configured, also has the same technical effects as the die cutting device and / or winding device, that is, by detecting the tab connecting trace M1 on the tab material belt 10 during the process of die cutting the tab material belt 10 to produce tab units EA with tabs, and marking two defect marks M2 at a first preset interval on the upstream position of the tab connecting trace M1 of the tab material belt 10, and then detecting the defect mark M2 on the tab material belt 10 during the process of winding the tab material belt 10 to form an electrode assembly, and then according to the detection of two defect marks M2 on the tab material belt 10, the continuous two-time single winding of the tab material belt 10 according to the length of the tab material belt required for making two electrode assemblies, so as to save the materials of the separator, anode / cathode tab required for making two electrode assemblies, effectively solve the problem of large loss of the tab material belt 10, reduce the production cost of the battery, and also reduce the defective rate of the battery.

[0187] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, it is to be understood that the application embraces all such possible combinations.

[0188] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A method for rejecting defective pole piece, comprising the steps of: detecting a joint mark on a pole piece tape having a plurality of continuously distributed pole piece units; based on detecting that the pole piece tape has a joint mark, marking two defect identifiers at a first preset interval D1 upstream of the joint mark on the pole piece tape; detecting the defect identifiers on the pole piece tape being wound into an electrode assembly; based on detecting that the pole piece tape has two defect identifiers, separately winding the pole piece unit having the defect identifiers and the adjacent pole piece unit upstream of the pole piece unit having the defect identifiers.

2. The pole piece bad product rejection method of claim 1, wherein, During the die cutting of the pole piece tape, marking a unit identifier on at least one of the first and last pole tab on the pole piece unit.

3. The pole piece bad product rejection method of claim 1, wherein, The length L0 of the pole piece unit is greater than the first preset interval D1.

4. The pole piece bad product rejection method of claim 1, wherein, The first preset interval D1 satisfies 50mm≤D1≤200mm.

5. The pole piece bad product rejection method of claim 1, wherein, The distance between the defect identifier close to the joint mark and the joint mark on the pole piece tape is a second preset distance D2, and the length L0 of the pole piece unit is greater than the second preset distance D2. 6.A die cutting device, comprising: a winding unit for pulling the pole piece tape in a preset direction; a die cutting unit for die cutting a pole tab on the pole piece tape to generate a plurality of continuously distributed pole piece units; a joint detection unit for detecting a joint mark on the pole piece tape; a marking unit for marking a defect identifier on the pole piece tape having a joint mark; a first control unit in communication connection with the winding unit, the die cutting unit, the joint detection unit and the marking unit; wherein when the joint detection unit detects that the pole piece tape has a joint mark, the marking unit marks two defect identifiers at a first preset interval D1 upstream of the joint mark on the pole piece tape; and further comprising the steps of: detecting the defect identifiers on the pole piece tape being wound into an electrode assembly; based on detecting that the pole piece tape has two defect identifiers, separately winding the pole piece unit having the defect identifiers and the adjacent pole piece unit upstream of the pole piece unit having the defect identifiers. The joint detection unit is configured as an image collector.

7. The die cutting apparatus of claim 6, wherein, 8.A winding device, comprising: an anode unwinding unit for unwinding an anode pole piece; a cathode unwinding unit for unwinding a cathode pole piece; a separator unwinding unit for unwinding a separator; a winding needle for winding the anode pole piece and the cathode pole piece with the separator therebetween to prepare an electrode assembly; an identifier detection unit for detecting a defect identifier on the anode pole piece when the winding needle winds the anode pole piece; a second control unit in communication connection with the anode unwinding unit, the cathode unwinding unit, the separator unwinding unit, the winding needle and the identifier detection unit; and further comprising the steps of: detecting a joint mark on the anode pole piece having a plurality of continuously distributed pole piece units; ​ ​ based on detecting that the anode tab has a tape mark, marking two defect markers with a first preset interval D1 upstream of the tape mark where the anode tab is located; wherein, when the marker detection unit detects that the anode tab has two defect markers with a first preset interval D1, the second control unit controls the winding needle to individually wind the tab unit with the defect markers and the adjacent tab unit upstream of the tab unit with the defect markers, and correspondingly controls the cathode unwinding unit and the separator film unwinding unit to stop unwinding.

9. A winding device, comprising: an anode unwinding unit for unwinding an anode tab; a cathode unwinding unit for unwinding a cathode tab; a separator film unwinding unit for unwinding a separator film; a winding needle for winding an anode tab and a cathode tab with a separator film therebetween to prepare an electrode assembly; a marker detection unit for defect marker detection on the cathode tab while the winding needle winds the cathode tab; a second control unit in communication connection with the anode unwinding unit, the cathode unwinding unit, the separator film unwinding unit, the winding needle, and the marker detection unit; and further comprising the following steps, detecting a tape mark on a cathode tab with a plurality of continuously distributed tab units; based on detecting that the cathode tab has a tape mark, marking two defect markers with a first preset interval D1 upstream of the tape mark where the cathode tab is located; wherein, when the marker detection unit detects that the cathode tab has two defect markers with a first preset interval D1, the second control unit controls the winding needle to individually wind the tab unit with the defect markers and the adjacent tab unit upstream of the tab unit with the defect markers, and correspondingly controls the anode unwinding unit and the separator film unwinding unit to stop unwinding.

10. The winding device according to claim 8 or 9, wherein The marker detection unit is configured as a chromatic aberration sensor.

11. A battery production system comprising the die cutting device of any one of claims 6 to 7 and the winding device of any one of claims 8 to 10.

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