Control method and device for battery welding based on dual-beam laser

Abstract

The embodiment of the present invention discloses a control method and device for battery welding based on dual-beam laser, wherein the control method includes: transferring a to-be-processed electrode sheet to a winding station; determining at least one first welding position or at least one second welding position on the to-be-processed electrode sheet, transferring at least one positive electrode ear / negative electrode ear to at least one first / second welding position respectively through an electrode ear transmission device, aligning the positive electrode ear / negative electrode ear with the to-be-processed electrode sheet, controlling the first laser emission head and the second laser emission head to weld the positive / negative electrode ear at the first / second welding position of the to-be-processed electrode sheet; detecting the to-be-processed electrode sheet after the electrode ear welding is completed; when the electrode ear welding is normal, winding the to-be-processed electrode sheet, and post-processing the electrode sheet, so that the post-processed electrode ear meets the preset requirements. The present invention can improve the accuracy of laser welding of lithium batteries, reduce the defective rate, and improve the battery quality of lithium batteries.

Description

Technical Field

[0001] The present invention relates to the technical fields of laser welding and lithium battery, and in particular to a control method and device for battery welding based on dual-beam laser. Background Art

[0002] Laser cutting is a non-contact processing method. The laser cutting head focuses the laser on the surface of the material for thermal processing to complete the cutting of the material. With the development of laser cutting technology, laser cutting can be used to cut more and more materials and achieve good cutting results. In the field of lithium batteries, during the manufacturing process of lithium batteries, the pole pieces need to be cut and then further processed according to the cut pole pieces to obtain lithium batteries. If the pole pieces cannot be cut accurately, or there are obvious defects in the pole pieces after cutting, the quality or yield of the lithium battery will be significantly reduced. Summary of the invention

[0003] Based on this, it is necessary to propose a control method, device and system for battery welding based on dual-beam laser to address the above problems.

[0004] In the first part of the present invention, a control method for battery welding based on dual-beam laser is provided, the method is used for lithium battery production equipment including laser welding equipment, the laser welding equipment includes a first laser emitting head and a second laser emitting head, wherein the first laser emitting head is used to emit a first laser beam, the second laser emitting head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different;

[0005] The electrode piece to be processed is transferred to a winding station, wherein the electrode piece to be processed is one of multiple electrode pieces of a lithium battery;

[0006] Before winding the electrode sheet to be processed, determining at least one first welding position or at least one second welding position on the electrode sheet to be processed, wherein the first welding position corresponds to the welding position of the positive electrode sheet and is used for welding the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet and is used for welding the negative electrode ear;

[0007] Transferring at least one positive electrode tab to the at least one first welding position through the tab transfer device, aligning the positive electrode tab with the electrode piece to be processed, and controlling the first laser emitter and the second laser emitter to weld the positive electrode tab to the first welding position of the electrode piece to be processed;

[0008] Transferring at least one negative electrode tab to the at least one second welding position through the tab transfer device, aligning the negative electrode tab with the electrode piece to be processed, and controlling the first laser emitter and the second laser emitter to weld the negative electrode tab to the second welding position of the electrode piece to be processed;

[0009] Inspect the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required;

[0010] In case of abnormal lug welding, the electrode sheet to be processed is transferred to the abnormal workstation and discarded. In case of normal lug welding, the electrode sheet to be processed is wound and post-processed after winding, so that the post-processed electrode sheet meets the preset requirements.

[0011] Optionally, the lithium battery includes multiple pole sheets, and the pole sheet to be processed after the multiple pole sheets are wound includes multiple positive pole ears and multiple negative pole ears, wherein the distance between any two positive pole ears or two negative pole ears is greater than or equal to a preset first distance threshold, and the distance between the multiple positive pole ears and the multiple negative pole ears is greater than or equal to a second distance threshold.

[0012] Optionally, the step of determining at least one first welding position or at least one second welding position on the electrode sheet to be processed before winding the electrode sheet to be processed also includes: collecting first image information of the electrode sheet to be processed by a camera device provided on the lithium battery production equipment; analyzing the first image information to determine whether there are first-type defects and second-type defects on the electrode sheet to be processed; when there are first-type defects on the electrode sheet to be processed, transferring the electrode sheet to be processed to an abnormal workstation to discard the electrode sheet to be processed; when only second-type defects exist on the electrode sheet to be processed, determining position information corresponding to the second-type defects, and determining at least one first welding position or at least one second welding position on the electrode sheet to be processed according to the determined position information, wherein the first welding position and the second welding position do not overlap with the position information, and the distance between the first welding position and the position information, and the distance between the second welding position and the position information are both less than a preset distance threshold.

[0013] Optionally, the step of transmitting at least one positive electrode ear to the at least one first welding position through the electrode ear transmission device, aligning the positive electrode ear with the electrode piece to be processed, and controlling the first laser emission head and the second laser emission head to weld the positive electrode ear at the first welding position of the electrode piece to be processed also includes: determining the first welding position on the electrode piece to be processed, and determining the third welding position of the positive electrode ear; controlling the electrode ear transmission device to overlap the welding surface of the positive electrode ear on the first welding surface on the electrode piece to be processed, and making the first welding position and the third welding position overlap, and At least one first welding point is determined on the surface, and the first laser emitter and the second laser emitter are controlled to weld the at least one determined first welding point, so that the welding surface of the positive electrode ear is welded to the first welding surface of the electrode piece to be processed, and the first welding position and the second welding position are welded through at least one first welding point; the step of transmitting at least one negative electrode ear to the at least one second welding position through the electrode ear transmission device, aligning the negative electrode ear with the electrode piece to be processed, and controlling the first laser emitter and the second laser emitter to weld the negative electrode ear at the second welding position of the electrode piece to be processed, also includes:

[0014] Determine a second welding position on the electrode to be processed, and determine a fourth welding position of the negative electrode ear; control the electrode ear transmission device to overlap the welding surface of the negative electrode ear on the second welding surface of the electrode to be processed, and make the second welding position and the fourth welding position overlap, and determine at least one second welding point on the welding surface of the negative electrode ear and the second welding surface of the electrode to be processed, and control the first laser emitter and the second laser emitter to weld the at least one determined second welding point, so that the welding surface of the negative electrode ear is welded to the second welding surface of the electrode to be processed, and the third welding position and the fourth welding position are welded through at least one second welding point.

[0015] Optionally, the first welding point and the second welding point each include a first welding path and a second welding path, and there is an overlap of one or two welding points between the first welding path and the second welding path, and the overlapping welding point is the starting point or end point of the first welding path or the second welding path; the step of controlling the first laser emitter and the second laser emitter to weld at least one determined welding point also includes: controlling the first laser emitter to emit a first laser beam to weld at least one welding point on the first welding path; controlling the second laser emitter to emit a second laser beam to weld at least one welding point on the second welding path; wherein the start time and end time of welding of the first welding path by the first laser beam and the welding of the second welding path by the second laser beam are consistent.

[0016] Optionally, the first welding path and the second welding path are a combination of one or more of a curve, a bow shape, a U-shape, and a spiral shape.

[0017] Optionally, the step of detecting the electrode piece to be processed that has completed the electrode tab welding to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required also includes: collecting second image information of the electrode piece to be processed that has completed the electrode tab welding by a camera device provided on the lithium battery production equipment; analyzing the second image information to determine whether there are third-category defects and fourth-category defects on the electrode piece to be processed that has completed the electrode tab welding; in the case where the third-category defects exist on the electrode piece to be processed that has completed the electrode tab welding, transferring the electrode piece to be processed to an abnormal workstation to discard the electrode piece to be processed; in the case where only the fourth-category defects exist on the electrode piece to be processed that has completed the electrode tab welding, determining the position information corresponding to the fourth-category defects, and determining the supplementary welding method for the four types of defects; according to the determined position information and the determined supplementary welding method, controlling the first laser emitter head or the second laser emitter head to perform supplementary welding.

[0018] In a second aspect of the present invention, a control device for battery welding based on dual-beam laser is provided, which is applied to a lithium battery production device including a laser welding device, wherein the laser welding device includes a first laser emitting head and a second laser emitting head, wherein the first laser emitting head is used to emit a first laser beam, and the second laser emitting head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different;

[0019] The device comprises:

[0020] A welding position determination module is used to transfer a to-be-processed electrode sheet to a winding station, wherein the to-be-processed electrode sheet is one of a plurality of electrode sheets of a lithium battery; before winding the to-be-processed electrode sheet, at least one first welding position or at least one second welding position on the to-be-processed electrode sheet is determined, wherein the first welding position corresponds to the welding position of the positive electrode sheet and is used for welding the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet and is used for welding the negative electrode ear;

[0021] A first welding module, used for respectively transferring at least one positive electrode tab to the at least one first welding position through a tab transfer device, aligning the positive electrode tab with the electrode piece to be processed, and controlling the first laser emitter and the second laser emitter to weld the positive electrode tab to the first welding position of the electrode piece to be processed;

[0022] A second welding module is used to transfer at least one negative electrode tab to the at least one second welding position through the electrode tab transmission device, align the negative electrode tab with the electrode piece to be processed, and control the first laser emission head and the second laser emission head to weld the negative electrode tab to the second welding position of the electrode piece to be processed;

[0023] The welding detection module is used to detect the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required;

[0024] Abnormal discard module, used to transfer the electrode to be processed to the abnormal station and discard it in case of abnormal welding of the electrode ear;

[0025] The winding module is used to wind the electrode sheet to be processed when the electrode ear welding is normal, and to post-process the electrode sheet after the winding is completed so that the post-processed electrode ear meets the preset requirements.

[0026] The embodiments of the present invention have the following beneficial effects:

[0027] After adopting the above-mentioned control method and device for battery welding based on dual-beam laser, it is applied to lithium battery production equipment including laser welding equipment, wherein the laser welding equipment includes a first laser emitting head and a second laser emitting head, wherein the first laser emitting head is used to emit a first laser beam, and the second laser emitting head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different; in the manufacturing process of the lithium battery, the electrode sheet to be processed is transmitted to the winding station, and the electrode sheet to be processed is one of multiple electrode sheets of the lithium battery; before winding the electrode sheet to be processed, at least one first welding position or at least one second welding position on the electrode sheet to be processed is determined, wherein the first welding position corresponds to the welding position of the positive electrode sheet, which is used to weld the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet, which is used to weld the negative electrode ear; at least one positive electrode is respectively wound by the electrode ear transmission device. The electrode tab is transferred to the at least one first welding position, and the positive electrode tab is aligned with the electrode piece to be processed, and the first laser emitter and the second laser emitter are controlled to weld the positive electrode tab to the first welding position of the electrode piece to be processed; at least one negative electrode tab is transferred to the at least one second welding position by the electrode tab transmission device, and the negative electrode tab is aligned with the electrode piece to be processed, and the first laser emitter and the second laser emitter are controlled to weld the negative electrode tab to the second welding position of the electrode piece to be processed; the electrode piece to be processed that has completed the electrode tab welding is detected to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required; in the case of abnormal electrode tab welding, the electrode piece to be processed is transferred to the abnormal station and discarded; in the case of normal electrode tab welding, the electrode piece to be processed is wound, and the electrode piece is post-processed after the winding is completed, so that the post-processed electrode tab meets the preset requirements.

[0028] That is to say, before the lithium battery pole piece is wound, the welding position of the positive and negative pole ears is first determined, and then the dual-beam laser emitting device is controlled to weld the positive and negative pole ears. After the welding is determined to be normal, the winding is performed again. This can better control the position of the pole ear welding and the accuracy of the pole ear welding, thereby improving the yield rate of the pole ear welding and the battery quality of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] in:

[0031] Figure 1 A schematic flow chart of a control method for battery welding based on dual-beam laser in one embodiment;

[0032] Figure 2 A schematic diagram of the composition of a control device for battery welding based on dual-beam laser in one embodiment;

[0033] Figure 3 The structure diagram of a computer device for running the above-mentioned control method of battery welding based on dual-beam laser in one embodiment. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In this embodiment, a control method for battery welding based on dual-beam laser is provided, which is applied to lithium battery production equipment, wherein the lithium battery production equipment includes laser welding equipment, and the laser welding equipment includes a first laser emission head and a second laser emission head, wherein the first laser emission head is used to emit a first laser beam, and the second laser emission head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different to achieve different welding functions and effects.

[0036] The lithium battery production equipment here is used to produce lithium batteries. In this embodiment, it involves the processes of pole piece winding and pole tab welding. The pole tab welding process is completed by the above-mentioned laser welding equipment.

[0037] Furthermore, the lithium battery production equipment also includes a camera device that can detect finished products or semi-finished products at corresponding production stations to determine whether the finished products or semi-finished products have defects and whether subsequent production processes can continue.

[0038] For details, see Figure 1 , a flow chart of the control method of the battery welding based on the dual-beam laser is given, and the control method of the battery welding based on the dual-beam laser includes: Figure 1 The following steps are shown:

[0039] Step S101: transferring a pole piece to be processed to a winding station, wherein the pole piece to be processed is one of a plurality of pole pieces of a lithium battery.

[0040] In the production process of lithium batteries, after the electrode processing is completed, the electrode (i.e. the electrode to be processed) needs to be further transferred to the winding station for winding. The lithium battery here includes multiple electrode sheets, and each electrode sheet is used as the electrode sheet to be processed and the subsequent steps are performed separately, that is, the corresponding electrode ear is welded to each electrode sheet.

[0041] Step S102: Before winding the electrode sheet to be processed, determine at least one first welding position or at least one second welding position on the electrode sheet to be processed, wherein the first welding position corresponds to the welding position of the positive electrode sheet and is used to weld the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet and is used to weld the negative electrode ear.

[0042] Before the electrode sheet to be processed is wound, the electrode ear needs to be welded first, and the electrode sheet that has completed the electrode ear welding will further undergo the electrode ear winding. In order to improve the accuracy of electrode ear welding, it is necessary to first determine the welding position on the electrode sheet to be processed. Among them, the electrode sheet to be processed includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet needs to weld the positive electrode ear, and the negative electrode sheet needs to weld the negative electrode ear. That is, the composite electrode sheet containing multiple electrode sheets corresponding to the lithium battery contains multiple positive electrode ears and multiple negative electrode ears, and therefore corresponds to at least one first welding position on the positive electrode sheet for welding the positive electrode ear, and at least one second welding position on the negative electrode sheet, corresponding to welding the negative electrode ear.

[0043] It should be noted that in this embodiment, the first welding position and the second welding position of the tab welding are required, because after the winding is completed, the distance between any two positive tabs or two negative tabs is greater than or equal to the preset first distance threshold, and the distance between multiple positive tabs and multiple negative tabs is greater than or equal to the second distance threshold, which is to avoid the unreasonable distance between the tabs leading to abnormal function of the lithium battery. Among them, the first distance threshold is less than the second distance threshold, because the isolation between the positive and negative tabs requires a larger distance.

[0044] Furthermore, the process of determining the first welding position and the second welding position further includes:

[0045] The first image information of the electrode to be processed is collected by a camera device installed on the lithium battery production equipment; the first image information is analyzed to determine whether there are first-type defects and second-type defects on the electrode to be processed; wherein the first-type defects refer to defects that directly affect the performance of the lithium battery, and the electrode with such defects cannot enter the subsequent process and needs to be discarded. Specifically, when the first-type defects exist on the electrode to be processed, the electrode to be processed is transferred to an abnormal station to be discarded.

[0046] Furthermore, the second type of defects refers to defects that do not affect the performance of the lithium battery, and subsequent processes can continue. Therefore, in the case where only the second type of defects exist on the electrode to be processed, the position information corresponding to the second type of defects is determined, and at least one first welding position or at least one second welding position on the electrode to be processed is determined according to the determined position information, wherein the first welding position and the second welding position do not overlap with the position information, and the distance between the first welding position and the position information, and the distance between the second welding position and the position information are both less than a preset distance threshold. Here, the determination of the first welding position and the second welding position, step by step, needs to consider not overlapping with the position information of the second type of defects, and also needs to consider the positional relationship limitation of the positive and negative pole ears mentioned above. In this way, the position of the pole ear can not only eliminate the influence of defects, but also ensure that the welding position of the pole ear can meet the quality requirements of the lithium battery.

[0047] Step S103: transporting at least one positive electrode tab to the at least one first welding position through the tab transport device, aligning the positive electrode tab with the electrode piece to be processed, and controlling the first laser emitter and the second laser emitter to weld the positive electrode tab at the first welding position of the electrode piece to be processed;

[0048] Step S104: transport at least one negative electrode tab to the at least one second welding position through the tab transport device, align the negative electrode tab with the electrode sheet to be processed, and control the first laser emitter and the second laser emitter to weld the negative electrode tab to the second welding position of the electrode sheet to be processed.

[0049] After the welding position is determined, the electrode tab welding can be further performed. Here, the positive and negative electrode tabs need to be first transferred to the corresponding first welding position and second welding position by the electrode tab transmission device, and then the positive and negative electrode tabs are aligned with the corresponding positive and negative electrode sheets in polarity, and then the first laser emission head and the second laser emission head are further controlled to weld the positive and negative electrode tabs to the first welding position or the second welding position on the positive and negative electrode sheets.

[0050] Specifically, first determine the first welding position on the electrode to be processed, and determine the third welding position of the positive electrode ear; wherein the first welding position and the second welding position correspond to each other and are welded together during the welding process. Control the electrode ear transmission device to overlap the welding surface of the positive electrode ear on the first welding surface of the electrode to be processed, and make the first welding position and the third welding position overlap, and determine at least one first welding point on the welding surface of the positive electrode ear and the first welding surface of the electrode to be processed, and control the first laser emitter and the second laser emitter to weld the at least one determined first welding point, so that the welding surface of the positive electrode ear is welded to the first welding surface of the electrode to be processed, and the first welding position and the second welding position are welded through at least one first welding point.

[0051] The corresponding welding points can be divided into a first welding path and a second welding path, wherein there is an overlap of one or two welding points between the first welding path and the second welding path, and the overlapping welding points are the starting point or end point of the first welding path or the second welding path. The first welding path and the second welding path here are actually a collection of multiple welding points, that is, at least one first welding point between the positive ear and the positive electrode sheet can be divided into two sets, one is at least one welding point included in the first welding path, and the other is at least one welding point included in the second welding path. There are only one or two welding points overlapped between the two sets, and there is no overlap of other welding points.

[0052] In the process of specifically controlling the first laser emitter and the second laser emitter to weld at least one determined welding point, the first laser emitter is controlled to emit the first laser beam to weld at least one welding point on the first welding path; the second laser emitter is controlled to emit the second laser beam to weld at least one welding point on the second welding path. This is because the first welding path and the second welding path correspond to different welding positions, and their requirements and functions for welding are different. In order to ensure the corresponding welding effect and improve the welding effect, the welding of the first welding path by the first laser beam and the welding of the second welding path by the second laser beam can be controlled, wherein the corresponding welding start time and end time of the two can be controlled to be consistent, so that the welding efficiency can be maximized.

[0053] Further, a second welding position on the electrode to be processed is determined, and a fourth welding position of the negative electrode ear is determined. The electrode ear transmission device is controlled to overlap the welding surface of the negative electrode ear on the second welding surface of the electrode to be processed, and the second welding position and the fourth welding position are overlapped, and at least one second welding point is determined on the welding surface of the negative electrode ear and the second welding surface of the electrode to be processed, and the first laser emitter and the second laser emitter are controlled to weld the at least one determined second welding point, so that the welding surface of the negative electrode ear is welded to the second welding surface of the electrode to be processed, and the third welding position and the fourth welding position are welded through at least one second welding point.

[0054] The corresponding welding points can be divided into a first welding path and a second welding path, wherein there is an overlap of one or two welding points between the first welding path and the second welding path, and the overlapping welding points are the starting point or end point of the first welding path or the second welding path. The first welding path and the second welding path here are actually a collection of multiple welding points, that is, at least one second welding point between the positive ear and the positive electrode sheet can be divided into two sets, one is at least one welding point included in the first welding path, and the other is at least one welding point included in the second welding path. There are only one or two welding points overlapped between the two sets, and there is no overlap of other welding points.

[0055] In the process of specifically controlling the first laser emitter and the second laser emitter to weld at least one determined welding point, the first laser emitter is controlled to emit the first laser beam to weld at least one welding point on the first welding path; the second laser emitter is controlled to emit the second laser beam to weld at least one welding point on the second welding path. This is because the first welding path and the second welding path correspond to different welding positions, and their requirements and functions for welding are different. In order to ensure the corresponding welding effect and improve the welding effect, the welding of the first welding path by the first laser beam and the welding of the second welding path by the second laser beam can be controlled, wherein the corresponding welding start time and end time of the two can be controlled to be consistent, so that the welding efficiency can be maximized.

[0056] It should be noted that in this embodiment, the welding points of the positive and negative tabs are welded using the same dual-beam laser as above, but the welding power, the number of light spots or welding points, and the shape of the welding path can be set differently according to the different requirements of the positive and negative tabs.

[0057] In another optional embodiment, the first welding path and the second welding path are a combination of one or more of a curve, a bow shape, a U-shape, and a spiral shape, and can be specifically set according to the positive electrode ear, the negative electrode ear or different welding positions to fully ensure the effect of the electrode ear welding.

[0058] Step S105: inspecting the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required.

[0059] Step S106: In case of abnormality in the electrode tab welding, the electrode sheet to be processed is transferred to the abnormal station and discarded. In case of normal electrode tab welding, the electrode sheet to be processed is wound, and after the winding is completed, the electrode sheet is post-processed so that the post-processed electrode tab meets the preset requirements.

[0060] In this embodiment, after the tab welding is completed, winding is not performed directly, and it is also necessary to determine whether the tab welding meets the quality requirements. Specifically, after the tab welding is completed, the electrode to be processed is inspected to determine whether there is an abnormality in the tab welding.

[0061] In the specific implementation, the second image information of the electrode piece to be processed after the electrode tab welding is completed is collected by a camera device installed on the lithium battery production equipment; the second image information is analyzed to determine whether there are third-type defects and fourth-type defects on the electrode piece to be processed after the electrode tab welding is completed; in the case that the third-type defect exists on the electrode piece to be processed after the electrode tab welding is completed, the electrode piece to be processed is transmitted to an abnormal workstation to be discarded; in the case that only the fourth-type defect exists on the electrode piece to be processed after the electrode tab welding is completed, the position information corresponding to the fourth-type defect is determined, and the supplementary welding method for the four types of defects is determined; according to the determined position information and the determined supplementary welding method, the first laser emitter head or the second laser emitter head is controlled to perform supplementary welding.

[0062] That is to say, whether there is a problem with the tab welding seems to be achieved through machine vision detection, and the image information corresponding to the tab welding to be detected (i.e., the second image information) is collected by a camera device, and then the second image information is analyzed based on machine vision to determine whether there is a corresponding defect in the tab welding. It should be noted that in this embodiment, the method for detecting defects in the tab welding can be any classification algorithm based on machine vision, which is not limited here.

[0063] In this embodiment, the defect detection of the tab welding needs to determine whether there are third-class defects and fourth-class defects in the tab welding on the electrode to be processed, wherein the third-class defect is a defect that will affect the performance of the tab and cannot enter the subsequent process of the product production, while the fourth-class defect is a defect that does not affect the performance of the tab, but for the purpose of the product yield and subsequent analysis, the fourth-class defect will still be detected here. In another embodiment, the fourth-class defect can also be a defect that can be compensated by supplementary welding, for example, the fourth-class defect can include defects such as missing welding or insufficient welding. Therefore, after determining the fourth-class defect, it is also necessary to determine the corresponding position information, and determine the supplementary welding method according to the specific defect parameters determined in the defect classification algorithm. The supplementary welding method here includes the corresponding first laser emitter or the second laser emitter, and the corresponding welding point position, laser emission power and at least one welding parameter, and then according to these welding parameters, the position where the fourth-class defect exists is supplemented with welding, so that the fourth-class defect no longer exists in the finished product, the product yield is improved, and the product quality of the corresponding lithium battery is improved.

[0064] It should be noted that in this embodiment, after the pole lug welding, not only can the post-processing method of supplementary welding be performed to improve the product quality, but other post-processing methods can also be used. For example, the burrs of the pole lug welding can be processed. Here, it is necessary to determine the position of the burrs during defect detection, and process the burrs after determining the position of the burrs, so that there are no burrs at the position of the pole lug welding in the finished product.

[0065] If there is no abnormality in the pole lug welding, or after post-processing such as supplementary welding and burr treatment, the pole piece to be processed after the pole lug welding can continue to be wound, so as to avoid the pole piece entering the winding being a pole piece with problems. In this embodiment, the reason why the pole lug welding is performed first and then the winding is performed is that there are many defects in the winding, and the probability of defects in the subsequent welding will increase. In order to reduce the defective rate here, the pole lug welding and abnormality detection are performed first, and then the winding is performed.

[0066] After the pole piece winding is completed, it is necessary to further detect and process the pole piece to be processed after the pole piece winding is completed, for example, to detect whether the pole piece winding is flat and whether it meets the preset related parameters, such as tightness, height, flatness, and whether the position relationship of the pole ear after winding is completed meets the preset parameters. If not, it is necessary to adjust the wound pole piece in a preset manner so that the position of the pole ear after winding is completed meets the preset requirements and the relevant parameters of the pole piece meet the preset requirements. Thereby further improving the yield rate of pole piece winding and improving the product quality of lithium batteries.

[0067] In another embodiment, Figure 2 As shown, a control device for battery welding based on dual-beam laser is also provided, which corresponds to the control method for battery welding based on dual-beam laser, and the device includes:

[0068] The welding position determination module 101 is used to transfer the electrode sheet to be processed to the winding station, wherein the electrode sheet to be processed is one of the multiple electrode sheets of the lithium battery; before winding the electrode sheet to be processed, at least one first welding position or at least one second welding position on the electrode sheet to be processed is determined, wherein the first welding position corresponds to the welding position of the positive electrode sheet and is used for welding the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet and is used for welding the negative electrode ear;

[0069] The first welding module 102 is used to transfer at least one positive electrode tab to the at least one first welding position through the electrode tab transmission device, align the positive electrode tab with the electrode piece to be processed, and control the first laser emission head and the second laser emission head to weld the positive electrode tab to the first welding position of the electrode piece to be processed;

[0070] The second welding module 103 is used to transfer at least one negative electrode tab to the at least one second welding position through the tab transmission device, align the negative electrode tab with the electrode piece to be processed, and control the first laser emission head and the second laser emission head to weld the negative electrode tab to the second welding position of the electrode piece to be processed;

[0071] The welding detection module 104 is used to detect the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required;

[0072] The abnormal discarding module 105 is used to transfer the electrode piece to be processed to the abnormal station and discard it when the electrode ear welding is abnormal;

[0073] The winding module 106 is used to wind the electrode sheet to be processed when the electrode tab welding is normal, and to post-process the electrode sheet after the winding is completed, so that the post-processed electrode tab meets the preset requirements.

[0074] Optionally, in one embodiment, the lithium battery includes multiple pole sheets, and the pole sheet to be processed after the multiple pole sheets are wound includes multiple positive pole ears and multiple negative pole ears, wherein the distance between any two positive pole ears or two negative pole ears is greater than or equal to a preset first distance threshold, and the distance between the multiple positive pole ears and the multiple negative pole ears is greater than or equal to a second distance threshold.

[0075] Optionally, in one embodiment, the welding position determination module 101 is also used to collect first image information of the electrode to be processed through a camera device provided on the lithium battery production equipment; analyze the first image information to determine whether there are first-type defects and second-type defects on the electrode to be processed; when there are first-type defects on the electrode to be processed, transfer the electrode to be processed to an abnormal workstation to discard the electrode to be processed; when only second-type defects exist on the electrode to be processed, determine the position information corresponding to the second-type defects, and determine at least one first welding position or at least one second welding position on the electrode to be processed according to the determined position information, wherein the first welding position and the second welding position do not overlap with the position information, and the distance between the first welding position and the position information, and the distance between the second welding position and the position information are both less than a preset distance threshold.

[0076] Optionally, in one embodiment, the first welding module 102 is also used to determine a first welding position on the electrode sheet to be processed, and to determine a third welding position of the positive electrode ear; control the electrode ear transmission device to overlap the welding surface of the positive electrode ear on the first welding surface of the electrode sheet to be processed, and make the first welding position and the third welding position overlap, and determine at least one first welding point on the welding surface of the positive electrode ear and the first welding surface of the electrode sheet to be processed, and control the first laser emitter and the second laser emitter to weld the at least one determined first welding point, so that the welding surface of the positive electrode ear is welded to the first welding surface of the electrode sheet to be processed, and the first welding position and the second welding position are welded through at least one first welding point.

[0077] Optionally, in one embodiment, the second welding module 103 is also used to determine a second welding position on the electrode sheet to be processed, and to determine a fourth welding position of the negative electrode ear; control the electrode ear transmission device to overlap the welding surface of the negative electrode ear on the second welding surface of the electrode sheet to be processed, and make the second welding position and the fourth welding position overlap, and determine at least one second welding point on the welding surface of the negative electrode ear and the second welding surface of the electrode sheet to be processed, and control the first laser emitter and the second laser emitter to weld the at least one determined second welding point, so that the welding surface of the negative electrode ear is welded to the second welding surface of the electrode sheet to be processed, and the third welding position and the fourth welding position are welded through at least one second welding point.

[0078] Optionally, in one embodiment, the first welding point and the second welding point each include a first welding path and a second welding path, respectively, and there is an overlap of one or two welding points between the first welding path and the second welding path, and the overlapping welding point is the starting point or the end point of the first welding path or the second welding path;

[0079] The first welding module 102 and the second welding module 103 are also used to control the first laser emission head to emit a first laser beam to weld at least one welding point on the first welding path; control the second laser emission head to emit a second laser beam to weld at least one welding point on the second welding path; wherein the start time and end time of the welding of the first welding path by the first laser beam and the welding of the second welding path by the second laser beam are consistent.

[0080] Optionally, in one embodiment, the first welding path and the second welding path are a combination of one or more of a curve, a bow shape, a U-shape, and a spiral shape.

[0081] Optionally, in one embodiment, the welding detection module 104 is further used to collect second image information of the electrode piece to be processed after the electrode tab welding is completed through a camera device provided on the lithium battery production equipment; analyze the second image information to determine whether there are third-type defects and fourth-type defects on the electrode piece to be processed after the electrode tab welding is completed;

[0082] In the case that the electrode piece to be processed after the electrode tab welding is subjected to the third type of defect, the abnormal discarding module 105 is called to transfer the electrode piece to be processed to the abnormal station so as to discard the electrode piece to be processed;

[0083] When only the fourth type of defect exists on the electrode piece to be processed after the electrode lug welding is completed, the first welding module 102 and the second welding module 103 are called to determine the position information corresponding to the fourth type of defect and determine the supplementary welding method for the fourth type of defect; according to the determined position information and the determined supplementary welding method, the first laser emitter head or the second laser emitter head is controlled to perform supplementary welding.

[0084] After adopting the above-mentioned control method and device for battery welding based on dual-beam laser, it is applied to lithium battery production equipment including laser welding equipment, wherein the laser welding equipment includes a first laser emitting head and a second laser emitting head, wherein the first laser emitting head is used to emit a first laser beam, and the second laser emitting head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different; in the manufacturing process of the lithium battery, the electrode sheet to be processed is transmitted to the winding station, and the electrode sheet to be processed is one of multiple electrode sheets of the lithium battery; before winding the electrode sheet to be processed, at least one first welding position or at least one second welding position on the electrode sheet to be processed is determined, wherein the first welding position corresponds to the welding position of the positive electrode sheet, which is used to weld the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet, which is used to weld the negative electrode ear; at least one positive electrode is respectively wound by the electrode ear transmission device. The electrode tab is transferred to the at least one first welding position, and the positive electrode tab is aligned with the electrode piece to be processed, and the first laser emitter and the second laser emitter are controlled to weld the positive electrode tab to the first welding position of the electrode piece to be processed; at least one negative electrode tab is transferred to the at least one second welding position by the electrode tab transmission device, and the negative electrode tab is aligned with the electrode piece to be processed, and the first laser emitter and the second laser emitter are controlled to weld the negative electrode tab to the second welding position of the electrode piece to be processed; the electrode piece to be processed that has completed the electrode tab welding is detected to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required; in the case of abnormal electrode tab welding, the electrode piece to be processed is transferred to the abnormal station and discarded; in the case of normal electrode tab welding, the electrode piece to be processed is wound, and the electrode piece is post-processed after the winding is completed, so that the post-processed electrode tab meets the preset requirements.

[0085] That is to say, before the lithium battery pole piece is wound, the welding position of the positive and negative pole ears is first determined, and then the dual-beam laser emitting device is controlled to weld the positive and negative pole ears. After the welding is determined to be normal, the winding is performed again. This can better control the position of the pole ear welding and the accuracy of the pole ear welding, thereby improving the yield rate of the pole ear welding and the battery quality of the lithium battery.

[0086] Figure 3 The internal structure diagram of a computer device for implementing the control method of the smart TV in one embodiment is shown. The computer device can be a terminal or a server. Figure 3 As shown, the computer device includes a processor, a memory and a network interface connected via a system bus. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the above method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can implement the above method. Those skilled in the art can understand that Figure 3 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0087] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0088] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations 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 protection scope of the present application shall be subject to the attached claims.

Claims

1. A control method for battery welding based on dual-beam laser, characterized in that: The method is used for lithium battery production equipment including a laser welding device, wherein the laser welding device includes a first laser emitting head and a second laser emitting head, wherein the first laser emitting head is used to emit a first laser beam, the second laser emitting head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different; The method comprises: The electrode sheet to be processed is transferred to a winding station, wherein the electrode sheet to be processed is one of multiple electrode sheets of a lithium battery; the lithium battery comprises multiple electrode sheets, and the electrode sheet to be processed after the winding of multiple electrode sheets comprises multiple positive electrode ears and multiple negative electrode ears, wherein the distance between any two positive electrode ears or two negative electrode ears is greater than or equal to a preset first distance threshold, and the distance between the multiple positive electrode ears and the multiple negative electrode ears is greater than or equal to a second distance threshold, and the first distance threshold is less than the second distance threshold; Before winding the electrode sheet to be processed, collecting first image information of the electrode sheet to be processed by a camera device arranged on a lithium battery production device; analyzing the first image information to determine whether there are first-type defects and second-type defects on the electrode sheet to be processed; In the case where the first type of defects exist on the electrode piece to be processed, the electrode piece to be processed is transferred to an abnormal workstation to be discarded; In the case that only the second type of defects exist on the electrode sheet to be processed, position information corresponding to the second type of defects is determined, and at least one first welding position or at least one second welding position on the electrode sheet to be processed is determined according to the determined position information of the second type of defects, wherein the first welding position corresponds to the welding position of the positive electrode sheet, which is used for welding the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet, which is used for welding the negative electrode ear, and the first welding position and the second welding position do not overlap with the position of the second type of defects, and the distance between the first welding position and the position of the second type of defects, and the distance between the second welding position and the position of the second type of defects are both less than a preset third distance threshold; The at least one positive electrode tab is respectively transferred to the at least one first welding position by the electrode tab transfer device, and the positive electrode tab is aligned with the electrode sheet to be processed, and the first laser emitter and the second laser emitter are controlled to weld the positive electrode tab to the first welding position of the electrode sheet to be processed through at least one first welding point; the at least one negative electrode tab is respectively transferred to the at least one second welding position by the electrode tab transfer device, and the negative electrode tab is aligned with the electrode sheet to be processed, and the first laser emitter and the second laser emitter are controlled to weld the negative electrode tab to the second welding position of the electrode sheet to be processed through at least one second welding point; Inspect the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required; In case of abnormal ear welding, the electrode to be processed is transferred to the abnormal station and discarded; When the electrode tab welding is normal, the electrode sheet to be processed is wound, and after the winding is completed, the electrode sheet is post-processed so that the post-processed electrode tab meets the preset requirements; Wherein, at least one first welding point and at least one second welding point each include a first welding path and a second welding path, respectively, there is an overlap of one or two welding points between the first welding path and the second welding path, and the overlapping welding point is the starting point or the end point of the first welding path or the second welding path; The step of controlling the first laser emitting head and the second laser emitting head to weld the positive electrode tab to the first welding position of the electrode piece to be processed through at least one first welding point also includes: controlling the first laser emitting head to emit a first laser beam to weld at least one first welding point on the first welding path; controlling the second laser emitting head to emit a second laser beam to weld at least one first welding point on the second welding path; The step of controlling the first laser emitter and the second laser emitter to weld the negative electrode ear to the second welding position of the electrode piece to be processed through at least one second welding point also includes: controlling the first laser emitter to emit a first laser beam to weld at least one second welding point on the first welding path; controlling the second laser emitter to emit a second laser beam to weld at least one second welding point on the second welding path; The start time and the end time of the welding of the first welding path by the first laser beam and the welding of the second welding path by the second laser beam are consistent.

2. The control method for battery welding based on dual-beam laser according to claim 1, characterized in that: The step of respectively transmitting at least one positive electrode tab to the at least one first welding position through the tab transmission device, aligning the positive electrode tab with the electrode piece to be processed, and controlling the first laser emission head and the second laser emission head to weld the positive electrode tab to the first welding position of the electrode piece to be processed through at least one first welding point also includes: Determine a first welding position on the electrode piece to be processed, and determine a third welding position of the positive electrode ear; Controlling the electrode tab transmission device to overlap the welding surface of the positive electrode tab on the first welding surface of the electrode piece to be processed, and making the first welding position overlap with the third welding position, and determining at least one first welding point on the welding surface of the positive electrode tab and the first welding surface of the electrode piece to be processed, and controlling the first laser emitting head and the second laser emitting head to weld the at least one determined first welding point, so that the welding surface of the positive electrode tab is welded to the first welding surface of the electrode piece to be processed, and the first welding position is welded to the third welding position through at least one first welding point; The step of respectively transmitting at least one negative electrode tab to the at least one second welding position through the tab transmission device, aligning the negative electrode tab with the electrode piece to be processed, and controlling the first laser emission head and the second laser emission head to weld the negative electrode tab at the second welding position of the electrode piece to be processed through at least one second welding point also includes: Determining a second welding position on the electrode piece to be processed, and determining a fourth welding position of the negative electrode ear; The pole ear transmission device is controlled to overlap the welding surface of the negative pole ear on the second welding surface of the pole piece to be processed, and the second welding position and the fourth welding position are overlapped, and at least one second welding point is determined on the welding surface of the negative pole ear and the second welding surface of the pole piece to be processed, and the first laser emitter and the second laser emitter are controlled to weld the at least one determined second welding point, so that the welding surface of the negative pole ear is welded to the second welding surface of the pole piece to be processed, and the second welding position and the fourth welding position are welded through at least one second welding point.

3. The control method for battery welding based on dual-beam laser according to claim 1, characterized in that: The first welding path and the second welding path are a combination of one or more of a bow shape, a U-shape, and a spiral shape.

4. The control method for battery welding based on dual-beam laser according to claim 1, characterized in that: The step of detecting the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required also includes: The second image information of the electrode piece to be processed after the electrode tab welding is completed is collected by a camera device arranged on the lithium battery production equipment; Analyze the second image information to determine whether there are third-type defects and fourth-type defects on the electrode piece to be processed after the electrode tab welding is completed; In the case that the third type of defect exists on the electrode piece to be processed after the electrode tab welding is completed, the electrode piece to be processed is transferred to the abnormal station to be discarded; In the case that only the fourth type of defect exists on the electrode piece to be processed after the electrode tab welding is completed, determining the position information corresponding to the fourth type of defect, and determining the supplementary welding method for the fourth type of defect; According to the determined position information of the fourth type of defect and the determined supplementary welding method, the first laser emitting head or the second laser emitting head is controlled to perform supplementary welding.

5. A control device for battery welding based on dual-beam laser, characterized in that: The device is used for the control method of battery welding based on dual-beam laser as described in any one of claims 1 to 4; The device is applied to a lithium battery production device including a laser welding device, wherein the laser welding device includes a first laser emitting head and a second laser emitting head, wherein the first laser emitting head is used to emit a first laser beam, and the second laser emitting head is used to emit a second laser beam, and the laser types of the first laser beam and the second laser beam are different; The device comprises a welding position determination module, a first welding module, a second welding module, a welding detection module, an abnormal discarding module, and a winding module, wherein: A welding position determination module, used for transferring a to-be-processed electrode sheet to a winding station, wherein the to-be-processed electrode sheet is one of a plurality of electrode sheets of a lithium battery; the lithium battery comprises a plurality of electrode sheets, and the to-be-processed electrode sheet after winding the plurality of electrode sheets comprises a plurality of positive electrode ears and a plurality of negative electrode ears, wherein the distance between any two positive electrode ears or two negative electrode ears is greater than or equal to a preset first distance threshold, and the distance between the plurality of positive electrode ears and the plurality of negative electrode ears is greater than or equal to a second distance threshold, and the first distance threshold is less than the second distance threshold; before winding the to-be-processed electrode sheet, collecting first image information of the to-be-processed electrode sheet by a camera device provided on a lithium battery production equipment; analyzing the first image information to determine whether there are first-type defects and second-type defects on the to-be-processed electrode sheet; and determining whether there are first-type defects on the to-be-processed electrode sheet. , calling the abnormal abandonment module to transfer the electrode to be processed to the abnormal station to abandon the electrode to be processed; in the case that only the second type of defects exist on the electrode to be processed, determining the position information corresponding to the second type of defects, and determining at least one first welding position or at least one second welding position on the electrode to be processed according to the determined position information of the second type of defects, wherein the first welding position corresponds to the welding position of the positive electrode sheet, which is used to weld the positive electrode ear, and the second welding position corresponds to the welding position of the negative electrode sheet, which is used to weld the negative electrode ear, and the first welding position and the second welding position do not overlap with the position of the second type of defects, and the distance between the first welding position and the position of the second type of defects, and the distance between the second welding position and the position of the second type of defects are both less than a preset third distance threshold; A first welding module, used for respectively transferring at least one positive electrode tab to the at least one first welding position through a tab transfer device, aligning the positive electrode tab with the electrode piece to be processed, and controlling the first laser emitter and the second laser emitter to weld the positive electrode tab to the first welding position of the electrode piece to be processed through at least one first welding point; A second welding module is used to transfer at least one negative electrode tab to the at least one second welding position through the tab transmission device, align the negative electrode tab with the electrode piece to be processed, and control the first laser emission head and the second laser emission head to weld the negative electrode tab to the second welding position of the electrode piece to be processed through at least one second welding point; The welding detection module is used to detect the electrode piece to be processed after the electrode tab welding is completed to determine whether there is any abnormality in the electrode tab welding and whether post-processing is required; Abnormal discard module, used to transfer the electrode to be processed to the abnormal station and discard it in case of abnormal welding of the electrode ear; The winding module is used to wind the electrode sheet to be processed when the electrode ear welding is normal, and to post-process the electrode sheet after the winding is completed, so that the electrode ear after post-processing meets the preset requirements; Wherein, at least one first welding point and at least one second welding point each include a first welding path and a second welding path, respectively, there is an overlap of one or two welding points between the first welding path and the second welding path, and the overlapping welding point is the starting point or the end point of the first welding path or the second welding path; The first welding module is also used to control the first laser emitter to emit a first laser beam to weld at least one first welding point on the first welding path; control the second laser emitter to emit a second laser beam to weld at least one first welding point on the second welding path; the second welding module is also used to control the first laser emitter to emit a first laser beam to weld at least one second welding point on the first welding path; control the second laser emitter to emit a second laser beam to weld at least one second welding point on the second welding path, and the start time and end time of the welding of the first welding path by the first laser beam and the welding of the second welding path by the second laser beam are consistent.

6. The control device for battery welding based on dual-beam laser according to claim 5, characterized in that: The first welding module is further used to determine a first welding position on the electrode to be processed, and to determine a third welding position of the positive electrode ear; control the electrode ear transmission device to overlap the welding surface of the positive electrode ear on the first welding surface of the electrode to be processed, and make the first welding position and the third welding position overlap, and determine at least one first welding point on the welding surface of the positive electrode ear and the first welding surface of the electrode to be processed, and control the first laser emitter and the second laser emitter to weld the at least one determined first welding point, so that the welding surface of the positive electrode ear is welded to the first welding surface of the electrode to be processed, and the first welding position and the third welding position are welded through at least one first welding point; The second welding module is also used to determine a second welding position on the electrode sheet to be processed, and to determine a fourth welding position of the negative electrode ear; control the electrode ear transmission device to overlap the welding surface of the negative electrode ear on the second welding surface of the electrode sheet to be processed, and make the second welding position and the fourth welding position overlap, and determine at least one second welding point on the welding surface of the negative electrode ear and the second welding surface of the electrode sheet to be processed, and control the first laser emitter and the second laser emitter to weld the at least one determined second welding point, so that the welding surface of the negative electrode ear is welded to the second welding surface of the electrode sheet to be processed, and the second welding position and the fourth welding position are welded through at least one second welding point.

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