Method and system for monitoring redundancy of battery cell tabs

Abstract

The invention discloses a method and system for monitoring the redundancy of tabs of a battery cell, the battery cell comprises multiple layers of roll cores, the method comprises the following steps: after the tabs of all the roll cores are welded on a welding table, the tabs corresponding to all the roll cores are fixed on a test board, and the height of the test board is the same as that of the welding table; collecting a target image including all the roll cores, all the tabs and the test bench; identifying a first feature point of each layer of tab corresponding to the roll core and a second feature point of a welding mark closest to the corresponding roll core in each layer of tab from the target image; according to the first distance and the second distance corresponding to each layer of tabs, the actual redundancy of the corresponding layer of tabs is determined, the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point. According to the scheme, the measurement and calculation of the redundancy of the tabs can be completed in a short time, the monitoring efficiency is greatly improved, and the yield of the battery cells is further improved.

Description

Technical Field

[0001] This application belongs to the technical field of power batteries, and particularly relates to a method and system for monitoring the redundancy of cell tabs. Background Art

[0002] With the improvement of the energy density and safety design capabilities of power battery cells, more and more cell designs adopt the technology of no connecting pieces and full tabs. In the assembly process of a square shell cell with a full tab design, it is necessary to first perform ultrasonic welding on the tabs to form all the tabs through ultrasonic welding, and then weld the tabs to the pole posts through laser welding. To avoid the breakage of the tabs during the assembly and use processes and take into account the adaptation of the process manufacturing, an appropriate redundancy of the tabs is required in the design. If the redundancy is too small, there is a risk of the tabs being torn and disconnected; if the redundancy is too large, in a limited space, the extra tabs are very likely to face the positive and negative electrode plates, short-circuit with the positive and negative electrode plates or even cause internal insertion, thus posing a risk of short circuit, which may lead to abnormal self-discharge at least, and thermal runaway at worst.

[0003] In the related art, it is usually necessary to perform a 360-degree full-scale CT scan on the cell sample to be tested to obtain hundreds or thousands of pictures, and then perform 3D reconstruction on these pictures to calculate the tab redundancy. The CT scan of the cell often takes at least 5 minutes, and if a clearer imaging effect is desired, each scan takes nearly 1 hour. For a normal mass production line, such a detection speed far cannot meet the full inspection requirements, so it is very easy to miss inspections. Based on this, how to quickly detect the tab redundancy to improve the yield rate of the cells is an urgent problem to be solved. Summary of the Invention

[0004] Embodiments of this application provide a method and system for monitoring the redundancy of cell tabs, which can at least quickly detect the tab redundancy to a certain extent, so as to improve the yield rate of the cells.

[0005] Other features and advantages of this application will become apparent through the following detailed description, or be learned in part through the practice of this application.

[0006] According to the first aspect of the embodiments of this application, a method for monitoring the redundancy of cell tabs is provided. The cell includes multiple layers of wound cores. The method for monitoring the redundancy of cell tabs includes:

[0007] After the tabs of all the wound cores are welded on the welding table, fix the tabs corresponding to all the wound cores on the test table, where the height of the test table is the same as that of the welding table;

[0008] Collect a target image including all the wound cores, all the tabs, and the test table;

[0009] Identify the first feature points of the current collector corresponding to each layer of tab in the target image and the second feature points of the solder mark closest to the current collector in each layer of tab.

[0010] Determine the actual redundancy of the corresponding layer of tab according to the first distance and the second distance corresponding to each layer of tab, where the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point.

[0011] In some embodiments, determining the actual redundancy of the corresponding layer of tab according to the first distance and the second distance corresponding to each layer of tab includes:

[0012] Determine the theoretical redundancy of the corresponding layer of tab according to trigonometric functions, the first distance and the second distance corresponding to each layer of tab;

[0013] Convert the theoretical redundancy of each layer of tab into the actual redundancy of the corresponding layer of tab.

[0014] In some embodiments, the multi-layer current collectors are placed horizontally, and the second feature points of the solder mark closest to the corresponding current collector in each layer of tab are the same.

[0015] In some embodiments, the method for monitoring the redundancy of the tab of the battery cell further includes:

[0016] Judge whether the battery cell is qualified according to the theoretical redundancy or the actual redundancy.

[0017] In some embodiments, judging whether the battery cell is qualified according to the theoretical redundancy or the actual redundancy includes:

[0018] Judge that the battery cell is qualified when the theoretical redundancy or the actual redundancy of each layer of tab is within the preset range;

[0019] Judge that the battery cell is unqualified when the theoretical redundancy or the actual redundancy of any layer of tab is not within the preset range.

[0020] In some embodiments, the method for monitoring the redundancy of the tab of the battery cell further includes:

[0021] Judge whether the corresponding layer of current collector is qualified according to the theoretical redundancy or the actual redundancy of each layer of tab.

[0022] According to the second aspect of the embodiments of the present application, a system for monitoring the redundancy of the tab of a battery cell is provided. The battery cell includes a multi-layer current collector. The system for monitoring the redundancy of the tab of the battery cell includes:

[0023] A fixing fixture, configured to fix all the tabs corresponding to all the current collectors on the test bench after the tabs of all the current collectors are welded on the welding bench, wherein the height of the test bench is the same as the height of the welding bench;

[0024] An image acquisition device for acquiring a target image including all core rolls, all tab ears, and a test bench;

[0025] An image processing device for identifying, from the target image, a first feature point of each layer of tab ears corresponding to the core roll and a second feature point of the solder mark closest to the core roll in each layer of tab ears, and determining the actual redundancy of the corresponding layer of tab ears according to the first distance and the second distance corresponding to each layer of tab ears, where the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point.

[0026] In some embodiments, the image processing device is further configured to determine the theoretical redundancy of the corresponding layer of tab ears according to trigonometric functions, the first distance, and the second distance corresponding to each layer of tab ears; and convert the theoretical redundancy of each layer of tab ears into the actual redundancy of the corresponding layer of tab ears.

[0027] In some embodiments, the system for monitoring the redundancy of the tab ears of the battery cell further includes a tab ear gripper for placing the positive tab ears or negative tab ears corresponding to all core rolls on the test bench; the fixing fixture is further configured to fix all the positive tab ears or negative tab ears corresponding to all core rolls on the test bench by pressing down, where the contact area between the fixing fixture and the positive tab ear or negative tab ear is smaller than the area of the solder mark in the positive tab ear or negative tab ear.

[0028] In some embodiments, the shooting parameters of the image acquisition device are determined according to the brightness of the battery cell and / or the brightness of the environment where the battery cell is located.

[0029] In this application, after the tab ears corresponding to all core rolls are welded on the welding table, all the tab ears corresponding to all core rolls are fixed on the test bench, where the height of the test bench is the same as that of the welding table; a target image including all core rolls, all tab ears, and the test bench is acquired; a first feature point of each layer of tab ears corresponding to the core roll and a second feature point of the solder mark closest to the core roll in each layer of tab ears are identified from the target image; the actual redundancy of the corresponding layer of tab ears is determined according to the first distance and the second distance corresponding to each layer of tab ears, where the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point. Compared with the CT scanning detection method, the above solution can complete the measurement of the tab ear redundancy in a short time, realize non-destructive full inspection in the battery cell production process, greatly improve the detection efficiency, and thus improve the yield of the battery cell. Compared with the ray detection method, it can avoid the interference of the negative tab ear to the positive tab ear during imaging, and the probability of missed detection and misdetection is lower, and it can identify unqualified battery cells at an earlier process (the tab ear redundancy forming stage), avoiding the production of battery cells with unqualified tab ear redundancy.

[0030] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit this application. Description of the Drawings

[0031] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application. Obviously, the drawings in the following description are only some embodiments of this application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0032] Figure 1 A flowchart showing a method for monitoring the redundancy of the electrode tabs of a battery cell according to some embodiments of this application;

[0033] Figure 2 A schematic diagram of an application scenario of a method for monitoring the redundancy of the electrode tabs of a battery cell according to some embodiments of this application;

[0034] Figure 3 Shows Figure 1 A schematic diagram of the first and second feature points in;

[0035] Figure 4 A functional module diagram of a system for monitoring the redundancy of the electrode tabs of a battery cell according to some embodiments of this application;

[0036] Figure 5 Shows Figure 4 An operation demonstration diagram of the electrode tab gripper in. Detailed Description of the Embodiments

[0037] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are only some, rather than all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in this application belong to the scope of protection of this application.

[0038] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to give a thorough understanding of the embodiments of this application. However, those skilled in the art will realize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be used. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of this application.

[0039] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0040] The flowcharts shown in the drawings are only exemplary descriptions and do not necessarily include all the content and operations / steps, nor do they have to be executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0041] It should also be noted that the terms "first", "second", etc. in the specification, claims and the above-mentioned drawings of this application are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the objects so used can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described.

[0042] At present, after a power battery is manufactured, it is impossible to directly detect whether the redundancy of the internal tabs is qualified or meets the product design requirements. If it is necessary to detect the redundancy of the tabs, usually two methods are adopted: non-destructive testing and destructive testing. Non-destructive testing mainly detects through offline CT scanning or ray detection, while destructive testing is carried out by cutting. CT scanning requires a 360-degree full-range scan of the battery cell to obtain hundreds or thousands of pictures, and then these pictures are reconstructed in 3D. Therefore, the CT scanning of the battery cell often takes at least 5 minutes. If a clearer imaging effect is desired, each scan takes nearly 1 hour. For a normal mass production line, such a detection speed far cannot meet the requirements of full inspection, and it is very easy to miss inspections. Although the ray detection has a higher detection speed compared with CT scanning, due to the limitation of the imaging principle, in order to avoid interference between the positive and negative tabs, the clarity and resolution will be reduced during imaging, resulting in inaccurate redundancy of the detected tabs. Cutting detection is a destructive detection method, and the battery cell after detection can hardly be used for other purposes and cannot be used as a full inspection method for normal mass production.

[0043] Based on the process parameters for forming the tab redundancy (the distance from the weld mark to the core and the height at which the weld mark is located), after all the cores complete tab welding on the welding table, all the tabs corresponding to the cores are fixed on the test table. Here, the height of the test table is the same as that of the welding table. The target image including all the cores, all the tabs, and the test table is collected. The first feature points of each layer of tabs corresponding to the core and the second feature points of the weld mark closest to the corresponding core in each layer of tabs are identified from the target image. According to the first distance and the second distance corresponding to each layer of tabs, the actual redundancy of the corresponding layer of tabs is determined. The first distance is the horizontal distance from the first feature point to the second feature point (equivalent to the distance from the weld mark to the core), and the second distance is the vertical distance from the first feature point to the second feature point (equivalent to the height at which the weld mark is located). Compared with the CT scanning detection method, the above solution can complete the measurement of the tab redundancy in a short time, achieve non-destructive full inspection during the production process of the battery cell, greatly improve the monitoring efficiency, and thus improve the yield of the battery cell. Compared with the ray detection method, it can avoid the interference of the negative tabs on the positive tabs during imaging, with a lower probability of missed detection and misdetection, and can identify unqualified battery cells at an earlier process (the tab redundancy forming stage), avoiding the production of battery cells with unqualified tab redundancy.

[0044] Figure 1 shows a schematic flow chart of a method for monitoring the tab redundancy of a battery cell according to some embodiments of the present application. As Figure 1 shown, a method for monitoring the tab redundancy of a battery cell is provided. The battery cell includes multiple layers of cores, and the method may include the following steps 101 to 104.

[0045] In step 101, after all the cores complete tab welding on the welding table, all the tabs corresponding to the cores are fixed on the test table. Here, the height of the test table is the same as that of the welding table.

[0046] For ease of understanding, the principle of the present application is first explained as follows: The battery cell forms a core by winding or stacking, and the core is automatically conveyed to the welding station through a conveying chain. Each layer of tab is neatly placed on the welding table through shaping or other means, and then the tab is pressed tightly by a tab pressing block to facilitate the welding operation. Therefore, the actual redundancy of each layer of tab will be affected by the welding process parameters (the distance from the weld mark to the core and the height where the weld mark is located). In the embodiments of the present application, the tabs corresponding to all cores are fixed on a test bench at the same height as the welding table, and a target image is collected. Through image recognition technology, the distance from the weld mark to the core and the height of the position of each layer of tab corresponding to the core from the weld mark position on the test bench (equivalent to the height where the weld mark is located in each layer of tab) are identified, and then the actual redundancy of each layer of tab is calculated. Although when welding, controlling these two process parameters, namely the distance from the weld mark to the core and the height where the weld mark is located, can basically control the redundancy of the tab to meet the design requirements. However, due to reasons such as materials, equipment, and processes, there are often certain deviations in the consistency of tab welding. Therefore, the present application can monitor the actual redundancy of each layer of tab after the battery cell is welded, thereby ensuring that all the produced battery cells meet the design requirements.

[0047] It can be understood that during the production process of the battery cell, it is usually necessary to convey the core to the welding table to complete the tab welding. After the tab welding is completed, all the tabs corresponding to the cores can be fixed on the test bench through a fixing fixture.

[0048] Figure 2 The application scenario diagram of the method for monitoring the tab redundancy of the battery cell according to some embodiments of the present application is shown. As Figure 2 shown, a tab gripper with a specific force value or other equivalent shaping tooling fixtures can be used to clamp the tab, and the tab is placed horizontally on a horizontal test bench at the same height as the welding table or other devices with universal adjustable angles. At the same time, the fixing fixture is pressed down to press the weld mark position in the tab. The contact area between the fixing fixture and the tab cannot be greater than the area of the weld mark in the tab and cannot exceed the weld mark interval to prevent interfering with the identification of the distance from the weld mark to the core, that is Figure 2 the l in

[0049] In step 102, a target image including all cores, all tabs, and the test bench is collected.

[0050] After the tab is fixed stably, the image acquisition device can be enabled to take a picture of all cores, all tabs, and the test bench as a whole to obtain the target image. In the embodiments of the present application, the image acquisition device includes but is not limited to industrial cameras, infrared devices, or other imaging devices such as lasers and sound waves.

[0051] It should be noted that the tabs corresponding to each layer of the core include a positive tab and a negative tab. All the positive tabs corresponding to the cores can be fixed on the test bench, and an object image including all the cores, all the positive tabs and the test bench is used for image recognition of the object image, and finally the actual redundancy of the positive tabs is determined; alternatively, all the negative tabs corresponding to the cores can be fixed on the test bench, and an object image including all the cores, all the negative tabs and the test bench is used for image recognition of the object image, and finally the actual redundancy of the negative tabs is determined.

[0052] The shooting parameters of the image acquisition device can be determined according to the brightness of the battery cell and / or the brightness of the environment where the battery cell is located. Among them, the shooting parameters can be the exposure time and the sensitivity. The exposure time affects the brightness and contrast of the object image. In the production of battery cells, the exposure time needs to be adjusted according to the brightness of the environment where the battery cell is located to avoid overexposure or underexposure, so as to ensure the clarity and details of the object image. The higher the sensitivity, the higher the sensitivity of the photosensitive element, and a brighter image can be captured in a low-light environment. However, if the sensitivity is too high, noise will appear in the image, which will affect the image quality. In the production of battery cells, the sensitivity needs to be determined according to the brightness of the environment where the battery cell is located and the brightness of the battery cell. If the brightness of the environment where the battery cell is located is relatively dark, the sensitivity can be appropriately increased, and vice versa, the sensitivity can be appropriately decreased to avoid the appearance of noise. Through the preset and debugged shooting parameters, the acquisition of the object image can be completed in a very short time.

[0053] In step 103, the first feature points corresponding to the cores of each layer of tabs and the second feature points of the solder joints closest to the corresponding cores in each layer of tabs are identified from the object image.

[0054] In the implementation process, the image processing device can be a device integrated with the image acquisition device or an independent device, and the embodiments of the present application do not limit this. If the image processing device and the image acquisition device are independent devices, the image processing device can obtain the object image from the image acquisition device and then process the object image.

[0055] In some embodiments, after the object image device obtains the object image, the object image can be processed such as sharpening, brightness and Fourier transform to obtain an object image with more prominent feature points, so as to improve the recognition result of the feature points in the object image.

[0056] Figure 3 shows Figure 1 a schematic diagram of the first feature point and the second feature point in. As Figure 3As shown in the figure, the first feature point corresponding to the core for one layer of tab is a1, and the first feature point corresponding to the core for the other layer of tab is a2. According to the different number of layers of the core, there can also be a3, a4, a5, etc. The second feature point of the weld mark closest to the corresponding core in one layer of tab is b1. Considering that the multiple cores in the battery cell are usually placed horizontally, the second feature point b1 of the weld mark closest to the corresponding core in each layer of tab is the same, so that repeated recognition of the second feature point can be avoided and the recognition efficiency can be improved.

[0057] In step 104, according to the first distance and the second distance corresponding to each layer of tab, determine the actual redundancy of the corresponding layer of tab, where the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point.

[0058] It can be understood that the actual redundancy of the tab refers to the redundancy of the length from the position corresponding to the core at the tab exit of each layer in the battery cell to the terminal post, which is equivalent to the additional dimensions added to the length, width, and thickness of the tab to cope with the mechanical stress caused by manufacturing process errors and assembly deviations during long-term use.

[0059] Continue to refer to Figure 3 , with the core placed horizontally, it can be considered that the horizontal distances l1, l2, l3, etc. from the first feature points a1, a2, a3, etc. corresponding to the core at the tab exit of each layer to the second feature point b1 are almost the same, that is, the first distance corresponding to each layer of tab is the same, denoted by l. The vertical heights h1, h2, h3, etc. from the first feature points a1, a2, a3, etc. corresponding to the core at the tab exit of each layer to the second feature point b1 are the second distances corresponding to each layer of tab.

[0060] In some embodiments, the theoretical redundancy of the corresponding layer of tab can be determined according to trigonometric functions, the first distance and the second distance corresponding to each layer of tab; and the theoretical redundancy of each layer of tab can be converted into the actual redundancy of the corresponding layer of tab.

[0061] Taking the first distance corresponding to each layer of tab as l and the second distance as h as an example, the theoretical redundancy s of the corresponding layer of tab can be calculated by the following formula:

[0062]

[0063] It can be understood that the redundancy s calculated based on the target image and image recognition technology is the theoretical redundancy, and the theoretical redundancy can be converted into the actual redundancy based on the number of pixels of the target image.

[0064] In some embodiments, after determining the theoretical redundancy or the actual redundancy, it can be judged whether the battery cell is qualified according to the theoretical redundancy or the actual redundancy.

[0065] In the implementation process, when the theoretical redundancy or actual redundancy of each layer of tab is within the preset range, the battery cell can be determined to be qualified; when the theoretical redundancy or actual redundancy of any layer of tab is not within the preset range, the battery cell is determined to be unqualified. In this way, it is possible to effectively determine whether the produced battery cells are qualified.

[0066] In some embodiments, after determining the theoretical redundancy or actual redundancy, it is also possible to determine whether the corresponding layer of core is qualified according to the theoretical redundancy or actual redundancy.

[0067] It can be understood that each battery cell design has a design value range for the redundancy of the tab. By comparing the calculated value with the design value, if the redundancy of the tab of a certain layer is within the design value range, the core of the corresponding layer is determined to be qualified, and the product flows to the next process. On the contrary, if the redundancy of the tab of a certain layer is not within the design value range, it is considered that the redundancy of the tab is too large, and there are risks such as internal insertion after entering the shell, then the core of the corresponding layer is determined to be unqualified, and the core flows into the waste core process. In this way, it is possible to avoid producing battery cells with unqualified tab redundancy.

[0068] In the embodiment of the present application, after all cores complete tab welding on the welding table, all tabs corresponding to the cores are fixed on the test bench, where the height of the test bench is the same as that of the welding table; a target image including all cores, all tabs, and the test bench is collected; the first feature points of each layer of tab corresponding to the core and the second feature points of the weld mark closest to the core in each layer of tab are identified from the target image; according to the first distance and the second distance corresponding to each layer of tab, the actual redundancy of the corresponding layer of tab is determined, where the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point. Compared with the CT scan detection method, it can complete the measurement of tab redundancy in a short time, realize non-destructive full inspection in the battery cell production process, greatly improve the detection efficiency, and thus improve the yield of battery cells. Compared with the ray detection method, it can avoid the interference of the negative tab on the positive tab during imaging, and the probability of missed detection and misdetection is lower, and it can identify unqualified battery cells in an earlier process (the tab redundancy forming stage), avoiding the production of battery cells with unqualified tab redundancy.

[0069] Figure 4 The functional module diagram of the system for monitoring the tab redundancy of a battery cell according to some embodiments of the present application is shown. The battery cell includes multiple layers of cores, such as Figure 4As shown in the figure, the system for monitoring the redundancy of the tab of the battery cell includes: a fixed fixture 401, which is used to fix all the tabs corresponding to all the wound cores on the test bench after the tabs of all the wound cores are welded on the welding bench, wherein the height of the test bench is the same as that of the welding bench; an image acquisition device 402, which is used to acquire a target image including all the wound cores, all the tabs and the test bench; an image processing device 403, which is used to identify the first feature points of the corresponding wound core for each layer of tabs and the second feature points of the solder joints closest to the corresponding wound core in each layer of tabs from the target image, and determine the actual redundancy of the corresponding layer of tabs according to the first distance and the second distance corresponding to each layer of tabs, wherein the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point.

[0070] In some embodiments, the image processing device 403 is further used to determine the theoretical redundancy of the corresponding layer of tabs according to trigonometric functions, the first distance and the second distance corresponding to each layer of tabs; and convert the theoretical redundancy of each layer of tabs into the actual redundancy of the corresponding layer of tabs.

[0071] In some embodiments, the multi-layer wound cores are placed horizontally, and the second feature points of the solder joints closest to the corresponding wound core in each layer of tabs are the same.

[0072] In some embodiments, the image processing device 403 is further used to judge whether the battery cell is qualified according to the theoretical redundancy or the actual redundancy.

[0073] In some embodiments, the image processing device 403 is further used to determine that the battery cell is qualified when the theoretical redundancy or the actual redundancy of each layer of tabs is within the preset range; and determine that the battery cell is unqualified when the theoretical redundancy or the actual redundancy of any layer of tabs is not within the preset range.

[0074] In some embodiments, the image processing device 403 is further used to judge whether the corresponding layer of wound cores is qualified according to the theoretical redundancy or the actual redundancy of each layer of tabs.

[0075] Figure 5 is shown Figure 4 the operation demonstration diagram of the tab gripper in. As Figure 5 shown, in some embodiments, the system for monitoring the redundancy of the tab of the battery cell further includes a tab gripper, which is used to place the positive tabs or negative tabs corresponding to all the wound cores on the test bench; the fixed fixture is further used to fix all the positive tabs or negative tabs corresponding to all the wound cores on the test bench by pressing down, wherein the contact area between the fixed fixture and the positive tab or negative tab is smaller than the area of the solder joint in the positive tab or negative tab.

[0076] In some embodiments, the shooting parameters of the image acquisition device 403 are determined according to the brightness of the battery cell and / or the brightness of the environment where the battery cell is located.

[0077] Through the design of the system for monitoring the redundant amount of the battery cell tab in the embodiments of the present application, the measurement of the redundant amount of the tab can be completed in a short time, greatly improving the detection efficiency, and thus improving the yield rate of the battery cell.

[0078] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on a computer-readable medium or transmitted via a computer-readable medium as one or more instructions or codes. Other examples and implementations are within the scope and spirit of the present application and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. In addition, each functional unit can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit.

[0079] In several embodiments provided in the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are merely illustrative. For example, the division of the units can be a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be through some interfaces, and the indirect couplings or communication connections of the units or modules can be in electrical or other forms.

[0080] The units described as separate components may or may not be physically separated. The components serving as control devices may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0081] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The foregoing storage medium includes: various media such as USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks, or optical discs that can store computer program instructions.

[0082] The above are only the embodiments of this application and are not intended to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims

1. A method for monitoring the redundancy of a battery cell tab, characterized in that: The battery cell includes a multi-layer winding core, and the method includes: After all the winding cores have completed the pole tab welding on the welding table, the pole tabs corresponding to all the winding cores are fixed on the test table, wherein the height of the test table is the same as the height of the welding table; Acquire a target image including all winding cores, all tabs and the test bench; Identify from the target image a first feature point of each layer of tabs corresponding to the winding core and a second feature point of the weld mark in each layer of tabs that is closest to the corresponding winding core; According to the first distance and the second distance corresponding to each layer of the pole ears, the actual redundancy of the corresponding layer of the pole ears is determined, wherein the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point.

2. The method for monitoring the redundancy of the battery cell tabs according to claim 1, characterized in that: The determining the actual redundancy of the corresponding layer of tabs according to the first distance and the second distance corresponding to each layer of tabs includes: Determine the theoretical redundancy of the corresponding layer of tabs according to the trigonometric function, the first distance and the second distance corresponding to each layer of tabs; The theoretical redundancy of each layer of tabs is converted into the actual redundancy of the tabs of the corresponding layer.

3. The method for monitoring the redundancy of the battery cell tabs according to claim 2, characterized in that: The multi-layer winding core is placed horizontally, and the second characteristic point of the weld mark in each layer of the pole ear that is closest to the corresponding winding core is the same.

4. The method for monitoring the redundancy of the battery cell tabs according to claim 2, characterized in that: Also includes: Whether the battery cell is qualified is determined according to the theoretical redundancy or the actual redundancy.

5. The method for monitoring the redundancy of the battery cell tabs according to claim 4, characterized in that: The step of judging whether the battery cell is qualified according to the theoretical redundancy or the actual redundancy includes: When the theoretical redundancy or the actual redundancy of each layer of the tabs is within a preset range, the battery cell is determined to be qualified; When the theoretical redundancy or the actual redundancy of any layer of the tabs is not within the preset range, the battery cell is determined to be unqualified.

6. The method for monitoring the redundancy of the battery cell tabs according to claim 2, characterized in that: Also includes: According to the theoretical redundancy or the actual redundancy of each layer of tabs, it is determined whether the winding core of the corresponding layer is qualified.

7. A system for monitoring the redundancy of battery cell tabs, characterized in that: The battery cell includes a multi-layer winding core, and the system includes: A fixing fixture is used to fix the pole tabs corresponding to all the winding cores on the test bench after the pole tabs of all the winding cores are welded on the welding bench, wherein the height of the test bench is the same as the height of the welding bench; An image acquisition device, used for acquiring target images including all winding cores, all tabs and the test bench; An image processing device is used to identify from the target image the first feature point of each layer of the pole lug corresponding to the winding core and the second feature point of the weld mark in each layer of the pole lug that is closest to the corresponding winding core, and determine the actual redundancy of the corresponding layer of the pole lug based on the first distance and the second distance corresponding to each layer of the pole lug, wherein the first distance is the horizontal distance from the first feature point to the second feature point, and the second distance is the vertical distance from the first feature point to the second feature point.

8. The system for monitoring the redundancy of battery cell tabs according to claim 7, characterized in that: The image processing device is also used to determine the theoretical redundancy of the corresponding layer of pole ears according to the trigonometric function, the first distance and the second distance corresponding to each layer of pole ears; and convert the theoretical redundancy of each layer of pole ears into the actual redundancy of the corresponding layer of pole ears.

9. The system for monitoring the redundancy of battery cell tabs according to claim 7, characterized in that: It also includes a pole ear gripping clamp, which is used to place the positive pole ears or negative pole ears corresponding to all the winding cores on the test bench; the fixing fixture is also used to fix the positive pole ears or negative pole ears corresponding to all the winding cores on the test bench by pressing down, wherein the contact area between the fixing fixture and the positive pole ears or negative pole ears is smaller than the area of ​​the weld mark in the positive pole ears or negative pole ears.

10. The system for monitoring the redundancy of battery cell tabs according to claim 7, characterized in that: The shooting parameters of the image acquisition device are determined according to the brightness of the battery cell and / or the brightness of the environment in which the battery cell is located.

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