Battery cell detection method and system

Abstract

Embodiments of the present application provide a battery cell detection method and system. The method comprises: before winding an anode sheet, a cathode sheet, and a separator, acquiring a plurality of first film widths corresponding to a first main body portion of an anode film layer, and a plurality of second film widths corresponding to a second main body portion of a cathode film layer; acquiring a first electrode sheet misalignment amount obtained by performing X-ray inspection on a battery cell upon the completion of winding, wherein the first electrode sheet misalignment amount is the dimension by which, on the side of the battery cell away from an anode tab, the first main body portion of the anode sheet adjacent to each turn of the cathode sheet extends beyond the second main body portion of the cathode sheet; and on the basis of the plurality of first film widths, the plurality of second film widths, and the first electrode sheet misalignment amount, determining a second electrode sheet misalignment amount, wherein the second electrode sheet misalignment amount is the dimension by which, on the side of the battery cell close to the anode tab, the first main body portion of the anode sheet adjacent to each turn of the cathode sheet extends beyond the second main body portion of the cathode sheet.

Description

Battery Cell Testing Methods and Systems

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese patent application 202510068243.7, filed on January 16, 2025, entitled “Method and System for Detecting Battery Cells”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery cell winding technology, and in particular to a battery cell testing method and system. Background Technology

[0004] After the battery cell is wound, it is usually necessary to check whether the overhang of the anode film layer of the anode electrode exceeds the cathode film layer of the cathode electrode conforms to the standard. Currently, X-ray inspection is mostly used to determine the overhang after the battery cell is wound. However, since the material of the anode film layer is similar to that of the anode tab on the anode tab side, X-ray inspection has difficulty in effectively distinguishing the boundary between the anode tab and the anode electrode, resulting in poor accuracy of the overhang on the anode tab side, and thus unreliable battery cell inspection results. Summary of the Invention

[0005] This application provides a cell testing method and system that can obtain accurate second electrode misalignment and improve the reliability of cell testing results.

[0006] In a first aspect, embodiments of this application provide a battery cell testing method. The battery cell includes an anode electrode, a cathode electrode, and a separator. The anode electrode, cathode electrode, and separator are wound together. The anode electrode includes a first main body portion with an anode film layer and an anode tab without an anode film layer. The cathode electrode includes a second main body portion with a cathode film layer and a cathode tab without a cathode film layer.

[0007] The methods include:

[0008] Before the anode, cathode and diaphragm are wound, a plurality of first film widths corresponding to the first main body portion and a plurality of second film widths corresponding to the second main body portion are obtained.

[0009] The first electrode misalignment is obtained by X-ray inspection of the cell after winding. The first electrode misalignment is the size of the first main body of the adjacent anode electrode on the side of the cell away from the anode tab, where the second main body of the cathode electrode exceeds the first main body of the cathode electrode in each turn.

[0010] Based on multiple first film widths, multiple second film widths, and the first electrode misalignment, the second electrode misalignment is determined. The second electrode misalignment is the dimension by which the first main body portion of the adjacent anode electrode of each turn of the cathode electrode extends beyond the second main body portion of the cathode electrode on the side of the cell closest to the anode tab.

[0011] In this embodiment, the first film width of the first main body portion of the anode electrode with the anode film layer and the second film width of the second main body portion of the cathode electrode with the cathode film layer can be obtained before winding. The misalignment of the first electrode on the cathode tab side obtained by X-ray detection of the battery cell after winding can be obtained. Thus, the total electrode misalignment of the anode tab side and the cathode tab side after winding can be calculated based on the first film width and the second film width. Combined with the first electrode misalignment, the accurate misalignment of the second electrode on the anode tab side can be calculated. Battery cell detection based on the accurate first electrode misalignment and second electrode misalignment can improve the reliability of battery cell detection results.

[0012] In some embodiments, each ring of cathode electrode adjacent anode electrode includes an inner ring of anode electrode and an outer ring of anode electrode;

[0013] The second electrode misalignment is determined based on multiple first film widths, multiple second film widths, and the first electrode misalignment, including:

[0014] The second film width of the first cathode electrode is determined from a plurality of second film widths, and the first film width of the first inner ring anode electrode and the first film width of the first outer ring anode electrode are determined from a plurality of first film widths, wherein the first cathode electrode is any ring of cathode electrode, and the first inner ring anode electrode and the first outer ring anode electrode are adjacent anode electrodes of the first cathode electrode;

[0015] The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the second film width of the first cathode electrode, the first film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0016] The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the second film width of the first cathode electrode, the first film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0017] In this embodiment, for a cathode electrode sheet whose two surfaces both include a cathode film layer, for each turn of the wound cathode electrode sheet, its adjacent anode electrode sheet may include an inner anode electrode sheet and an outer anode electrode sheet adjacent to the two surfaces of that turn of the cathode electrode sheet, respectively. This allows for the calculation of the second electrode misalignment between the inner and outer anode electrodes adjacent to the cathode electrode sheet on both surfaces of that turn of the cathode electrode sheet, by combining the first film width, the second film width, and the first electrode misalignment of each turn of the cathode electrode sheet, along with the first electrode misalignment amount. This enables the determination of a more comprehensive second electrode misalignment amount, improving the reliability of cell testing results while saving computational resources.

[0018] In some embodiments, obtaining the first electrode misalignment amount obtained by X-ray detection of the cell after winding includes:

[0019] Obtain cross-sectional images of the battery cell after winding and then perform X-ray inspection;

[0020] Edge detection is performed on the cross-sectional image to obtain the first boundary of the first main body and the second boundary of the second main body on the side away from the anode tab;

[0021] The misalignment of the first electrode is determined based on the interval between the first boundary and the second boundary.

[0022] In this embodiment, edge detection can be performed using the cross-sectional image obtained by X-ray detection to obtain the accurate misalignment amount of the first electrode on the cathode tab side, thereby improving the accuracy of the misalignment amount of the second electrode and improving the reliability of the cell detection results.

[0023] In some embodiments, determining the misalignment of the first electrode based on the interval between the first boundary and the second boundary includes:

[0024] Obtain the first and second sub-boundary points belonging to the first cathode electrode on the second boundary, the third and fourth sub-boundary points belonging to the first inner anode electrode on the first boundary, and the fifth and sixth sub-boundary points belonging to the first outer anode electrode on the first boundary; wherein the first and second sub-boundary points, the third and fourth sub-boundary points, and the fifth and sixth sub-boundary points are symmetrically distributed along the central axis of the cell.

[0025] Determine the first interval between the first sub-boundary point and the third sub-boundary point, the second interval between the second sub-boundary point and the fourth sub-boundary point, the third interval between the first sub-boundary point and the fifth sub-boundary point, and the fourth interval between the second sub-boundary point and the sixth sub-boundary point;

[0026] The average of the first interval and the second interval is determined as the first electrode misalignment between the first cathode electrode and the first inner anode electrode;

[0027] The average of the third and fourth intervals is determined as the first electrode misalignment between the first cathode electrode and the first outer ring anode electrode.

[0028] In this embodiment, since there are two symmetrical contour points corresponding to the central axis of each circle of electrodes in the cross-sectional image, the first electrode misalignment of the two points can be calculated. The average of the two first electrode misalignment values ​​can be used as the first electrode misalignment between each circle of cathode electrode and the adjacent anode electrode, making the first electrode misalignment more accurate.

[0029] In some embodiments, before the anode electrode, cathode electrode, and separator are wound, obtaining a plurality of first film widths corresponding to the first main body portion and a plurality of second film widths corresponding to the second main body portion includes:

[0030] Before the anode electrode, cathode electrode and diaphragm are wound, a plurality of first sub-film widths corresponding to the first surface of the first main body, a plurality of second sub-film widths corresponding to the second surface of the first main body, a plurality of third sub-film widths corresponding to the first surface of the second main body, and a plurality of fourth sub-film widths corresponding to the second surface of the second main body are obtained.

[0031] The first surface is the surface facing the winding needle during the winding process, and the second surface is the surface away from the winding needle during the winding process.

[0032] In this embodiment, since there may be some deviations in the film widths of the two surfaces of the electrode, multiple first sub-film widths corresponding to the first surface of the anode electrode, multiple second sub-film widths corresponding to the second surface of the anode electrode, multiple third sub-film widths corresponding to the first surface of the cathode electrode, and multiple fourth sub-film widths corresponding to the second surface of the cathode electrode can be obtained separately. This can improve the accuracy of the film width data of the electrode, thereby improving the accuracy of the misalignment of the second electrode, and ultimately improving the reliability of the cell testing results.

[0033] In some embodiments, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and a first electrode misalignment includes:

[0034] Based on the fourth film width of the first cathode electrode, the third film width of the first inner ring anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner ring anode electrode, determine the second electrode misalignment between the first cathode electrode and the first inner ring anode electrode.

[0035] Based on the fourth film width of the first cathode electrode, the third film width of the first outer ring anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer ring anode electrode, determine the second electrode misalignment between the first cathode electrode and the first outer ring anode electrode.

[0036] The third film width is the minimum value between the first and second sub-film widths at the same length position on the anode electrode, and the fourth film width is the maximum value between the third and fourth sub-film widths at the same length position on the cathode electrode.

[0037] In this embodiment, the larger of the film widths on the two surfaces of the cathode electrode at the same location can be used to determine the film width at that location, and the smaller of the film widths on the two surfaces of the anode electrode at the same location can be used to determine the film width at that location. Thus, the difference between the first and second film widths at that location can be less than or equal to the actual difference, and the subsequently calculated misalignment of the second electrode can be less than or equal to the actual misalignment. This simplifies the amount of calculation data and reduces the risk of missed detections.

[0038] In some embodiments, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and a first electrode misalignment includes:

[0039] The misalignment of the second electrode between the first cathode electrode and the first inner anode electrode is determined based on the width of the third sub-film of the first cathode electrode, the width of the second sub-film of the first inner anode electrode, and the misalignment of the first electrode between the first cathode electrode and the first inner anode electrode.

[0040] The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the fourth sub-film width of the first cathode electrode, the first sub-film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0041] In this embodiment, the film width data corresponding to the surfaces adjacent to the cathode and anode electrodes can be used to calculate the misalignment of the second electrode between them, which improves the accuracy of the misalignment of the second electrode.

[0042] In some embodiments, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and a first electrode misalignment includes:

[0043] Based on the fourth film width of the first cathode electrode, the second sub-film width of the first inner ring anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner ring anode electrode, determine the second electrode misalignment between the first cathode electrode and the first inner ring anode electrode.

[0044] Based on the fourth film width of the first cathode electrode, the first sub-film width of the first outer ring anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer ring anode electrode, the second electrode misalignment between the first cathode electrode and the first outer ring anode electrode is determined.

[0045] The fourth film width is the maximum value of the third and fourth sub-film widths at the same length position of the cathode electrode.

[0046] In this embodiment, the film width at a given position can be determined by the larger of the film widths on the two surfaces of the cathode electrode at the same location. Then, the misalignment of the second electrode at that position can be calculated by combining the film widths on the surfaces of the actual adjacent anode electrodes at that position. This approach can simultaneously meet the dual requirements of accuracy and low computational cost.

[0047] In some embodiments, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and a first electrode misalignment includes:

[0048] The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the third sub-film width of the first cathode electrode, the third film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0049] The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the fourth sub-film width of the first cathode electrode, the third film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0050] The third membrane width is the minimum value between the first and second sub-membrane widths at the same length position on the anode electrode.

[0051] In this embodiment, the smaller value of the film width of the two surfaces of the anode electrode at the same position can be used to determine the film width at that position. Then, the film width of the actual adjacent cathode electrode surface at that position can be combined to calculate the misalignment of the second electrode at that position, which can simultaneously meet the dual requirements of accuracy and low computational data.

[0052] In some embodiments, each first film width is associated with the length information of the anode electrode, and each second film width is associated with the length information of the cathode electrode;

[0053] Determining the second film width of the first cathode electrode from a plurality of second film widths, and determining the first film width of the first inner anode electrode and the first film width of the first outer anode electrode from a plurality of first film widths, includes:

[0054] Based on the length information of the cathode electrode associated with multiple second film widths and the number of layers of the first cathode electrode, the second film width of the first cathode electrode is determined from multiple second film widths;

[0055] Based on the length information of the anode plates associated with multiple first film widths and the number of layers of the first cathode plate, the first film width of the first inner ring anode plate and the first film width of the first outer ring anode plate are determined from the multiple first film widths.

[0056] In this embodiment, the film width data corresponding to the electrode length can be matched according to the number of layers as the film width data corresponding to the current layer of electrode. The misalignment of the second electrode between the current layer of cathode electrode and its adjacent inner and outer anode electrodes is calculated, which improves the accuracy of the film width data and thus improves the accuracy of the misalignment of the second electrode.

[0057] In some embodiments, determining the second film width of the first cathode electrode from a plurality of second film widths based on the length information of the cathode electrodes associated with a plurality of second film widths and the number of layers of the first cathode electrode includes:

[0058] The following information is obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate.

[0059] The diameter of the first cathode electrode is determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode electrode, the thickness of the cathode electrode, the thickness of the diaphragm, the first gap, and the second gap.

[0060] The length of the cathode corresponding to the first cathode is determined based on the diameter of the first cathode.

[0061] The second film width of the first cathode electrode is determined from the multiple second film widths based on the length information of the cathode electrode associated with the multiple second film widths and the length of the cathode electrode.

[0062] In this embodiment, the diameter of each turn of the cathode electrode can be calculated based on the thickness of each layer of winding material, the first gap, and the second gap. Then, the electrode length corresponding to each turn of the cathode electrode can be determined based on the diameter, which lays the foundation for determining the second film width of each turn of the cathode electrode from multiple second film widths based on the length of this segment of the electrode.

[0063] In some embodiments, determining the length of the cathode corresponding to the first cathode based on the diameter of the first cathode includes:

[0064] The circumference of the first cathode electrode is determined based on its diameter.

[0065] The length of the cathode electrode corresponding to the first cathode electrode is determined by the sum of the circumference of the first cathode electrode and the circumferences of all cathode electrodes corresponding to the number of layers before the number of layers of the first cathode electrode.

[0066] In this embodiment, the circumference of each ring of cathode electrode can be calculated based on the diameter. Combined with the total circumference of the previous rings, the electrode length corresponding to each ring of cathode electrode can be determined, which lays the foundation for determining the second film width of each ring of cathode electrode from multiple second film widths based on the electrode length.

[0067] In some embodiments, determining the second film width of the first cathode electrode from a plurality of second film widths based on the length information of the cathode electrode associated with a plurality of second film widths and the length of the cathode electrode includes:

[0068] Determine at least one fifth film width whose length information is within the length of the cathode electrode from a plurality of second film widths;

[0069] The average value of at least one fifth film width is determined as the second film width of the first cathode electrode.

[0070] In this embodiment, if there is more than one second film width within the length of each cathode electrode, the average value can be calculated as the second film width of that cathode electrode. In this way, the second film width of each cathode electrode can be standardized, which indirectly improves the robustness of the data and thus improves the reliability of the cell testing results.

[0071] In some embodiments, determining the first film width of the first inner ring anode and the first film width of the first outer ring anode from a plurality of first film widths based on the length information of the anode sheets associated with a plurality of first film widths and the number of rings of the first cathode sheet includes:

[0072] The following information is obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate.

[0073] Based on the number of layers of the first cathode electrode, determine the number of layers of the first inner anode electrode and the number of layers of the first outer anode electrode;

[0074] The diameter of the first inner ring anode plate is determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap of the first inner ring anode plate. The diameter of the first outer ring anode plate is determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap of the first outer ring anode plate.

[0075] The length of the anode plate corresponding to the first inner ring anode plate is determined based on the diameter of the first inner ring anode plate, and the length of the anode plate corresponding to the first outer ring anode plate is determined based on the diameter of the first outer ring anode plate.

[0076] Based on the length information of the cathode plates associated with multiple second film widths, as well as the anode plate lengths corresponding to the first inner ring anode plate and the first outer ring anode plate, the first film width of the first inner ring anode plate and the first film width of the first outer ring anode plate are determined from multiple first film widths.

[0077] In this embodiment, the diameters of the inner and outer anode plates can be calculated based on the thickness of each layer of winding material, the first gap, and the second gap. Then, the corresponding electrode lengths of the inner and outer anode plates can be determined based on the diameters, laying the foundation for determining the first film widths of the inner and outer anode plates from multiple first film widths based on the electrode length.

[0078] In some embodiments, determining the anode length corresponding to the first inner ring anode sheet based on the diameter of the first inner ring anode sheet, and determining the anode length corresponding to the first outer ring anode sheet based on the diameter of the first outer ring anode sheet, includes:

[0079] The circumference of the first inner anode plate is determined based on the diameter of the first inner anode plate.

[0080] The circumference of the first outer ring anode plate is determined based on the diameter of the first outer ring anode plate;

[0081] The length of the cathode electrode corresponding to the first inner anode electrode is determined by the sum of the circumference of the first inner anode electrode and the circumference of the anode electrodes corresponding to all the layers before the first inner anode electrode.

[0082] The length of the cathode electrode corresponding to the first outer anode electrode is determined by the sum of the circumference of the first outer anode electrode and the circumferences of all anode electrodes corresponding to the number of layers before the first outer anode electrode.

[0083] In this embodiment, the circumference of the inner and outer anode plates can be calculated based on their diameters. Combined with the total circumference of the previous layers of the inner and outer anode plates, the lengths of the plates corresponding to the inner and outer anode plates can be determined respectively. This lays the foundation for determining the first film width of the inner and outer anode plates from multiple first film widths based on the length of the plate segment.

[0084] In some embodiments, determining the first film width of the first inner ring anode and the first film width of the first outer ring anode from a plurality of first film widths, based on the length information of the cathode plates associated with a plurality of second film widths, and the anode plate lengths corresponding to the first inner ring anode and the first outer ring anode, includes:

[0085] Determine at least one sixth film width whose length information is within the length of the anode corresponding to the first inner ring anode sheet from among a plurality of first film widths, and determine at least one seventh film width whose length information is within the length of the anode corresponding to the first outer ring anode sheet from among a plurality of first film widths;

[0086] The average value of at least one sixth film width is determined as the first film width of the first inner ring anode sheet, and the average value of at least one seventh film width is determined as the first film width of the first outer ring anode sheet.

[0087] In this embodiment, if there is more than one first film width within the length of each anode electrode, the average value can be calculated as the first film width of that anode electrode. In this way, the first film width of each anode electrode can be standardized, which indirectly improves the robustness of the data and thus improves the reliability of the cell testing results.

[0088] In some embodiments, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and a first electrode misalignment includes:

[0089] For each loop of cathode electrode, the first film width of the adjacent anode electrode is subtracted from the second film width of the cathode electrode to obtain the first difference.

[0090] Subtracting the first electrode misalignment between the cathode electrode and the adjacent anode electrode from the first difference yields the second electrode misalignment between the cathode electrode and the adjacent anode electrode.

[0091] In this embodiment, the total electrode misalignment on the anode tab side and cathode tab side after the cell winding is completed can be calculated based on the first film width and the second film width. Then, combined with the first electrode misalignment, the accurate second electrode misalignment on the anode tab side can be calculated. Based on the accurate first electrode misalignment and second electrode misalignment, the reliability of the cell detection results can be improved.

[0092] In some embodiments, the method further includes:

[0093] When both the misalignment of the first electrode and the misalignment of the second electrode are greater than a preset threshold, the cell is determined to meet the electrode alignment requirements. The preset threshold is the critical value at which the size of the first main body portion exceeding that of the second main body portion does not meet the electrode alignment requirements.

[0094] In this embodiment, when both the misalignment of the first electrode and the misalignment of the second electrode are greater than a preset threshold, it is determined that the cell meets the electrode alignment requirements, thereby improving the cell yield.

[0095] Secondly, embodiments of this application provide a battery cell testing system, comprising:

[0096] A winding machine includes a winding needle and an image acquisition mechanism. The winding needle is used to wind a battery cell, which includes an anode electrode, a cathode electrode, and a separator. The anode electrode, cathode electrode, and separator are wound together, and the anode electrode includes a first main body portion with an anode film layer and an anode tab without an anode film layer. The cathode electrode includes a second main body portion with a cathode film layer and a cathode tab without a cathode film layer. The image acquisition mechanism is used to acquire multiple first film widths corresponding to the first main body portion and multiple second film widths corresponding to the second main body portion before the anode electrode, cathode electrode, and separator are wound, and to transmit the acquired multiple first film widths and multiple second film widths to a processor.

[0097] The X-ray system is located downstream of the winding machine and is used to perform X-ray detection on the battery cell after winding to obtain the misalignment of the first electrode and transmit the misalignment of the first electrode to the processor.

[0098] The processor, connected to the image acquisition mechanism and the X-ray system, is used to execute the method as described in the first aspect.

[0099] In this embodiment, the first film width of the first main body portion of the anode electrode with the anode film layer and the second film width of the second main body portion of the cathode electrode with the cathode film layer can be obtained before winding. The misalignment of the first electrode on the cathode tab side obtained by X-ray detection of the battery cell after winding can be obtained. Thus, the total electrode misalignment of the anode tab side and the cathode tab side after winding can be calculated based on the first film width and the second film width. Combined with the first electrode misalignment, the accurate misalignment of the second electrode on the anode tab side can be calculated. Battery cell detection based on the accurate first electrode misalignment and second electrode misalignment can improve the reliability of battery cell detection results.

[0100] In some embodiments, the processor is further configured to:

[0101] The membrane width data and cell identifier are associated and stored. The membrane width data includes multiple first membrane widths and multiple second membrane widths of the cell corresponding to the cell identifier.

[0102] Based on the cell identifier, obtain the membrane width data associated with the cell.

[0103] In this embodiment, membrane width data and cell identifier can be stored in advance. Then, the membrane width data of the cell to be tested can be retrieved based on the cell identifier to calculate the misalignment of the second electrode, thus making the acquisition of membrane width data more flexible and intelligent during cell testing.

[0104] In some embodiments, the image acquisition mechanism includes:

[0105] A first camera is positioned facing the first surface of the anode sheet before it is wound, for acquiring a first image of the first surface of the anode sheet before it is wound;

[0106] A second camera, positioned facing the second surface of the previously wound anode electrode, is used to acquire a second image of the second surface of the previously wound anode electrode.

[0107] A third camera, positioned facing the first surface of the cathode electrode before winding, is used to acquire a third image of the first surface of the cathode electrode before winding.

[0108] A fourth camera, positioned facing the second surface of the previously wound cathode electrode, is used to acquire a fourth image of the second surface of the previously wound cathode electrode.

[0109] An image processor is configured to determine, based on a first image, a second image, a third image, and a fourth image, a plurality of first sub-film widths and a plurality of second sub-film widths of a first main body portion, and a plurality of third sub-film widths and a plurality of fourth sub-film widths of a second main body portion;

[0110] The first surface is the surface facing the winding needle during the winding process, and the second surface is the surface away from the winding needle during the winding process.

[0111] In this embodiment, since there may be some deviations in the film widths of the two surfaces of the electrode, multiple first sub-film widths corresponding to the first surface of the anode electrode, multiple second sub-film widths corresponding to the second surface of the anode electrode, multiple third sub-film widths corresponding to the first surface of the cathode electrode, and multiple fourth sub-film widths corresponding to the second surface of the cathode electrode can be obtained separately. This can improve the accuracy of the film width data of the electrode, thereby improving the accuracy of the misalignment of the second electrode, and ultimately improving the reliability of the cell testing results.

[0112] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0113] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0114] Figure 1 is a schematic flowchart of one of the battery cell testing methods provided in the embodiments of this application;

[0115] Figure 2 is a schematic diagram of the cell winding provided in an embodiment of this application;

[0116] Figure 3 is a schematic diagram of the battery cell after winding according to an embodiment of this application;

[0117] Figure 4 is a schematic diagram of a cross-sectional image provided in an embodiment of this application;

[0118] Figure 5 is a schematic diagram of the cross-sectional image provided in the embodiment of this application after edge detection;

[0119] Figure 6 is a second schematic flowchart of the cell testing method provided in the embodiments of this application;

[0120] Figure 7 is a third schematic flowchart of the cell testing method provided in the embodiments of this application;

[0121] Figure 8 is a fourth schematic flowchart of the cell testing method provided in the embodiments of this application;

[0122] Figure 9 is a fifth flowchart illustrating the cell testing method provided in the embodiments of this application;

[0123] Figure 10 is a schematic flowchart of the cell testing method provided in the embodiments of this application (the sixth one).

[0124] Figure 11 is a schematic flowchart of the cell testing method provided in the embodiment of this application (the seventh one).

[0125] Figure 12 is a schematic diagram of the cell testing system provided in an embodiment of this application.

[0126] The accompanying drawings are not drawn to scale.

[0127] Reference numerals: 200, battery cell; 210, anode electrode; 220, cathode electrode; 230, diaphragm; 2201, first cathode electrode; 2101, first inner anode electrode; 2102, first outer anode electrode; 300, winding machine; 310 winding needle; 400, image acquisition mechanism; 410, first camera; 420, second camera; 430, third camera; 440, fourth camera; 500, cross-sectional image; 510, central axis; 501, first boundary; 502, second boundary; 1201, X-ray system; 1202, processor. Detailed Implementation

[0128] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0129] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0130] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0131] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0132] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0133] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0134] In some embodiments, the cathode electrode may include a cathode current collector and a cathode active material (cathode film) disposed on at least one surface of the cathode current collector.

[0135] As an example, the cathode current collector has two surfaces opposite each other in its own thickness direction, and the cathode active material is disposed on either or both of the two opposite surfaces of the cathode current collector.

[0136] As an example, the cathode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0137] As an example, the cathode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery cathode active materials may also be used. These cathode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also abbreviated as NCM333), LiNi0.5Co0.2Mn0.3O2 (also abbreviated as NCM523), LiNi0.5Co The following are included: 0.25Mn0.25O2 (also known as NCM211), LiNi0.6Co0.2Mn0.2O2 (also known as NCM622), LiNi0.8Co0.1Mn0.1O2 (also known as NCM811), lithium nickel cobalt aluminum oxides (such as LiNi0.8Co0.15Al0.05O2), and their modified compounds. Modified compounds refer to substances obtained by doping or coating, etc., based on the above-mentioned materials.

[0138] In some embodiments, the anode electrode may include an anode current collector.

[0139] As an example, the anode current collector can be a metal foil, a conductive polymer material, a carbon material, or a composite current collector. For example, as a metal foil, pure metals, alloys, or surface-treated metals can be used, including but not limited to stainless steel, copper, aluminum, nickel, titanium, or silver. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0140] As an example, the anode electrode may include an anode current collector and an anode active material (anode film layer) disposed on at least one surface of the anode current collector.

[0141] As an example, the anode current collector has two surfaces opposite each other in its own thickness direction, and the anode active material is disposed on either or both of the two opposite surfaces of the anode current collector.

[0142] As an example, the anode active material may be any anode active material known in the art for use in battery cells. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as anode active materials for battery cells may also be used. These anode active materials may be used alone or in combination of two or more.

[0143] In some embodiments, the anode may be a foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the anode electrode, the surface of the foamed metal may or may not contain an anode active material.

[0144] As an example, anolyte active material can be filled or / and deposited within the anolyte current collector.

[0145] In some embodiments, the cathode current collector may be made of aluminum, and the anode current collector may be made of copper.

[0146] In some implementations, the cell also includes an isolation element disposed between the cathode and the anode.

[0147] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0148] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a single component located between the positive anodes or attached to the surface of the positive anode. An inorganic particle coating, an organic particle coating, or an organic / inorganic composite coating can also be applied to the surface of the separator.

[0149] This application provides a battery cell testing method and system to solve the above-mentioned technical problems. The battery cell testing method provided in this application is described first below.

[0150] Please refer to Figures 1 to 3. This application provides a battery cell testing method. The battery cell 200 may include an anode electrode 210, a cathode electrode 220, and a separator 230. The anode electrode 210, cathode electrode 220, and separator 230 are wound together. The anode electrode 210 includes a first main body portion with an anode film layer and an anode tab without an anode film layer. The cathode electrode 220 includes a second main body portion with a cathode film layer and a cathode tab without a cathode film layer.

[0151] Cell testing methods may include:

[0152] Step 101: Before the anode, cathode and separator are wound, a plurality of first film widths corresponding to the first main body and a plurality of second film widths corresponding to the second main body are obtained.

[0153] In step 101, as shown in FIG2, before the anode electrode 210, cathode electrode 220 and separator 230 are wound onto the winding needle 310 of the winding machine 300, an image of the surface of the anode electrode 210 and cathode electrode 220 is captured by a line array camera disposed facing at least one surface of the anode electrode 210 and cathode electrode 220. The first main body portion of the anode electrode 210 and the second main body portion of the cathode electrode 220 are identified by the image, and the film width data of the anode electrode 210 and cathode electrode 220 can be obtained. The film width data may include the first film width corresponding to the first main body portion and the second film width corresponding to the second main body portion.

[0154] Understandably, during the winding process of the anode electrode 210 and the cathode electrode 220, the anode electrode 210 and the cathode electrode 220 can move relative to each other along multiple rollers of the winding machine 300 and be wound onto the winding needle 310. Based on this, when the line scan camera takes pictures at a certain frequency from a fixed shooting point, it can capture images at fixed intervals along the length direction of the anode electrode 210 and the cathode electrode 220. In other words, it can acquire multiple first film widths at fixed length intervals on the anode electrode 210 and multiple second film widths at fixed length intervals on the cathode electrode 220. The first film width can refer to the width of the anode film layer coated on the anode electrode 210, and the second film width can refer to the width of the cathode film layer coated on the cathode electrode 220.

[0155] Step 102: Obtain the first electrode misalignment amount obtained by X-ray detection of the cell after winding. The first electrode misalignment amount is the size of the first main body portion of the adjacent anode electrode portion of the cell on the side of the cell away from the anode tab, where the second main body portion of the cathode electrode portion exceeds the first main body portion of the cathode electrode portion in each turn.

[0156] In step 102, the wound cell 200 can also be subjected to X-ray inspection. For example, an X-ray device can be used to scan the wound cell to obtain a cross-sectional image 500 as shown in Figure 4. In some examples, this cross-sectional image 500 can be directly acquired, and the boundary lines of the cathode tab, the second main body portion away from the anode tab, and the first main body portion in the cross-sectional image can be identified. The misalignment of the first electrode can then be calculated. This misalignment can be the dimension by which the first main body portion of the adjacent anode electrode 210 of each turn of the cathode electrode 220 extends beyond the second main body portion of that turn of the cathode electrode 220, away from the anode tab.

[0157] In other examples, the X-ray equipment can directly acquire the cross-sectional image 500 and process it to calculate the misalignment of the first electrode. In this way, during cell inspection, the misalignment of the first electrode calculated by the X-ray equipment can be directly obtained.

[0158] It is understandable that the anode and cathode tabs of the battery cell can be located on different sides. In this scenario, the side furthest from the anode tab can be considered the side of the cathode tab. In this case, the misalignment of the first electrode can be on the cathode tab side, and the first main body portion of the adjacent anode electrode 210 of each loop of cathode electrode 220 exceeds the size of the second main body portion of that loop of cathode electrode 220. Alternatively, the anode and cathode tabs of the battery cell can be located on the same side. In this scenario, the misalignment of the first electrode on the side furthest from the anode tab can be 0.

[0159] It is also understandable that when the anode and cathode tabs of the battery cell are located on different sides, the principle of X-ray detection of the misalignment of the first electrode plate lies in the significant difference between the material of the cathode tab and the material of the anode film coating on the anode plate. Therefore, the boundary line of the anode film layer can be clearly identified through X-ray detection. Based on this, the battery cell detection method provided in this application embodiment is not limited to the cutting method of the battery cell tabs, that is, it can be applied to battery cells with fully cut tabs as well as battery cells with half-cut tabs.

[0160] Step 103: Determine the second electrode misalignment based on multiple first film widths, multiple second film widths, and the first electrode misalignment amount. The second electrode misalignment amount is the size by which the first main body portion of the adjacent anode electrode of each turn of the cathode electrode extends beyond the second main body portion of the cathode electrode on the side of the cell closest to the anode tab.

[0161] In step 103, it is understood that after winding, the cell 200 typically has the first main body portion of the anode electrode 210 wrapping the second main body portion of the cathode electrode 220. Thus, the total electrode misalignment on both the anode and cathode tab sides can be calculated using multiple first film widths and multiple second film widths. This means that the first main body portion of the adjacent anode electrode 210 in each turn of the cathode electrode 220 exceeds the total size of the second main body portion of that turn of the cathode electrode 220. Based on the first electrode misalignment obtained from X-ray detection, the accurate second electrode misalignment can be calculated. The second electrode misalignment can be the size on the anode tab side where the first main body portion of the adjacent anode electrode 210 in each turn of the cathode electrode 220 exceeds the second main body portion of that turn of the cathode electrode 220.

[0162] The cell testing results can be determined by the relevant operators based on the misalignment of the first and second electrodes. Alternatively, the misalignment of the first and second electrodes can be compared with a standard threshold, and the cell testing result can be output based on the comparison result. The standard threshold can be preset or determined based on multiple first and second film widths; no specific limitation is made here.

[0163] In this embodiment, the first film width of the first main body portion of the anode electrode 210 with the anode film layer and the second film width of the second main body portion of the cathode electrode 220 with the cathode film layer can be obtained before winding. The first electrode misalignment on the cathode tab side obtained by X-ray detection of the battery cell 200 after winding can be obtained. Thus, the total electrode misalignment on the anode tab side and the cathode tab side after winding of the battery cell 200 can be calculated based on the first film width and the second film width. Combined with the first electrode misalignment, the accurate second electrode misalignment on the anode tab side can be calculated. Battery cell detection based on the accurate first electrode misalignment and second electrode misalignment can improve the reliability of battery cell detection results.

[0164] In some embodiments, as shown in FIG3, each ring of cathode electrode adjacent anode electrode includes an inner ring anode electrode and an outer ring anode electrode;

[0165] As shown in Figure 6, the misalignment of the second electrode is determined based on multiple first film widths, multiple second film widths, and the misalignment of the first electrode, including:

[0166] Step 601: Determine the second film width of the first cathode electrode from a plurality of second film widths, and determine the first film width of the first inner ring anode electrode and the first film width of the first outer ring anode electrode from a plurality of first film widths. The first cathode electrode is any ring of cathode electrodes, and the first inner ring anode electrode and the first outer ring anode electrode are adjacent anode electrodes of the first cathode electrode.

[0167] Step 602: Determine the second electrode misalignment between the first cathode electrode and the first inner anode electrode based on the second film width of the first cathode electrode, the first film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0168] Step 603: Determine the second electrode misalignment between the first cathode electrode and the first outer anode electrode based on the second film width of the first cathode electrode, the first film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0169] In this embodiment, as shown in FIG3, the diaphragm 230, anode plate 210, diaphragm 230, and cathode plate 220 are alternately arranged. Generally, both surfaces of the cathode plate 220 are coated with cathode active material; in other words, both surfaces of the cathode plate 220 include the second main body of the cathode film layer. Similarly, both surfaces of the anode plate 210 are coated with anode active material, and both surfaces of the anode plate 210 include the first main body of the anode film layer.

[0170] Based on this, each ring of cathode electrode 220 has an inner ring of anode electrode and an outer ring of anode electrode adjacent to it. For any ring of cathode electrode (first cathode electrode 2201), the second film width of the first cathode electrode 2201 can be determined from a plurality of second film widths, and the first film width of the first inner ring anode electrode 2101 and the first film width of the first outer ring anode electrode 2102 adjacent to the first cathode electrode 2201 can be determined from a plurality of first film widths.

[0171] For example, as shown in Figure 3, if the first cathode electrode 2201 is the first ring of cathode electrodes, then the first inner ring anode electrode 2101 is the first ring of anode electrodes, and the first outer ring anode electrode 2102 is the second ring of anode electrodes; if the first cathode electrode 2201 is the second ring of cathode electrodes, then the first inner ring anode electrode 2101 is the second ring of anode electrodes, and the first outer ring anode electrode 2102 is the third ring of anode electrodes; if the first cathode electrode 2201 is the third ring of cathode electrodes, then the first inner ring anode electrode 2101 is the third ring of anode electrodes, and the first outer ring anode electrode 2102 is the fourth ring of anode electrodes…

[0172] To facilitate understanding of the technical solutions of the embodiments of this application, the following description will take the first cathode electrode 2201 as the first ring of cathode electrodes, the first inner ring anode electrode 2101 as the first ring of anode electrodes, and the first outer ring anode electrode 2102 as the second ring of anode electrodes as an example.

[0173] For example, the second film width of the first ring of cathode electrodes can be determined from a plurality of second film widths, and the first film width of the first ring of anode electrodes and the first film width of the second ring of anode electrodes can be determined from a plurality of first film widths. In some examples, the average of the plurality of second film widths can be directly determined as the second film width of the first ring of cathode electrodes, that is, the average of the plurality of second film widths can be determined as the first film width of the first ring of anode electrodes and the first film width of the second ring of anode electrodes.

[0174] In other examples, the second film width corresponding to the position of the first ring of cathode electrodes can be obtained as the second film width of the first ring of cathode electrodes. It is understood that if there are multiple second film widths corresponding to a position, their average or maximum value can be used as the second film width of the first ring of cathode electrodes. Similarly, the first film width corresponding to the position of the first ring of anode electrodes and the second ring of anode electrodes can be obtained as the first film width of the first ring of anode electrodes and the second ring of anode electrodes, respectively. If there are multiple first film widths corresponding to a position, their average or minimum value can be used as the first film width of the first ring of anode electrodes and the second ring of anode electrodes.

[0175] The total electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101 can be calculated using the second film width of the first cathode electrode 2201 and the first film width of the first inner anode electrode 2101. Then, based on the first electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101, the accurate second electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101 can be calculated.

[0176] Similarly, based on the second film width of the first cathode electrode 2201 and the first film width of the first outer ring anode electrode 2102, the total electrode misalignment between the first cathode electrode 2201 and the first outer ring anode electrode 2102 can be calculated first. Then, based on the first electrode misalignment between the first cathode electrode 2201 and the first outer ring anode electrode 2102, the accurate second electrode misalignment between the first cathode electrode 2201 and the first outer ring anode electrode 2102 can be calculated.

[0177] In this embodiment, for a cathode electrode sheet whose two surfaces both include a cathode film layer, for each turn of the wound cathode electrode sheet, its adjacent anode electrode sheet may include an inner anode electrode sheet and an outer anode electrode sheet adjacent to the two surfaces of that turn of the cathode electrode sheet, respectively. This allows for the calculation of the second electrode misalignment between the inner and outer anode electrodes adjacent to the cathode electrode sheet on both surfaces of that turn of the cathode electrode sheet, by combining the first film width, the second film width, and the first electrode misalignment of each turn of the cathode electrode sheet, along with the first electrode misalignment amount. This enables the determination of a more comprehensive second electrode misalignment amount, improving the reliability of cell testing results while saving computational resources.

[0178] In some embodiments, as shown in FIG11, obtaining the first electrode misalignment amount obtained by X-ray detection of the cell after winding includes:

[0179] Step 1101: Obtain a cross-sectional image of the cell after winding and X-ray inspection;

[0180] Step 1102: Perform edge detection on the cross-sectional image to obtain the first boundary of the first main body and the second boundary of the second main body on the side away from the anode tab;

[0181] The misalignment of the first electrode is determined based on the interval between the first boundary and the second boundary.

[0182] In this embodiment, as shown in FIG4, a cross-sectional image 500 of the cell 200 after winding and X-ray inspection can be obtained. Edge detection is performed on the cross-sectional image 500, as shown in FIG5, to obtain the first boundary 501 of the first main body portion and the second boundary 502 of the second main body portion on the side away from the anode tab. It can be understood that the dimension by which the first boundary 501 exceeds the second boundary 502 can be considered the misalignment amount of the first electrode. Therefore, the interval between each second boundary point and the adjacent first boundary point can be calculated to obtain the misalignment amount of the first electrode.

[0183] In this embodiment, edge detection can be performed using the cross-sectional image 500 obtained by X-ray detection to obtain the accurate misalignment amount of the first electrode on the cathode tab side, thereby improving the accuracy of the misalignment amount of the second electrode and improving the reliability of the cell detection results.

[0184] In some embodiments, determining the misalignment of the first electrode based on the interval between the first boundary and the second boundary includes:

[0185] Obtain the first and second sub-boundary points belonging to the first cathode electrode on the second boundary, the third and fourth sub-boundary points belonging to the first inner anode electrode on the first boundary, and the fifth and sixth sub-boundary points belonging to the first outer anode electrode on the first boundary; wherein the first and second sub-boundary points, the third and fourth sub-boundary points, and the fifth and sixth sub-boundary points are symmetrically distributed along the central axis of the cell.

[0186] Determine the first interval between the first sub-boundary point and the third sub-boundary point, the second interval between the second sub-boundary point and the fourth sub-boundary point, the third interval between the first sub-boundary point and the fifth sub-boundary point, and the fourth interval between the second sub-boundary point and the sixth sub-boundary point;

[0187] The average of the first interval and the second interval is determined as the first electrode misalignment between the first cathode electrode and the first inner anode electrode;

[0188] The average of the third and fourth intervals is determined as the first electrode misalignment between the first cathode electrode and the first outer ring anode electrode.

[0189] In this embodiment, it is understood that, as shown in FIG. 5, each ring of cathode electrode 220 and anode electrode 210 has two boundary points symmetrically distributed along the central axis 510 of the battery cell. Based on this, the first and second sub-boundary points belonging to the first cathode electrode and symmetrically distributed along the central axis 510 of the battery cell on the second boundary 502 can be obtained. Furthermore, the third and fourth sub-boundary points of the first inner ring anode electrode on the first boundary 501, symmetrically distributed along the central axis 510 of the battery cell, and the fifth and sixth sub-boundary points of the first outer ring anode electrode on the first boundary 501, symmetrically distributed along the central axis 510 of the battery cell, can be obtained.

[0190] The first interval between the first sub-boundary point and the third sub-boundary point, and the second interval between the second sub-boundary point and the fourth sub-boundary point can be calculated separately. Then, the average of the first interval and the second interval can be calculated to obtain the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0191] Similarly, the third interval between the first and fifth sub-boundary points, and the fourth interval between the second and sixth sub-boundary points can be calculated separately. By calculating the average of the third and fourth intervals, the misalignment of the first electrode between the first cathode electrode and the first outer anode electrode can be obtained.

[0192] In this embodiment, since there are two symmetrical contour points corresponding to the central axis 510 for each circle of electrode in the cross-sectional image 500, the first electrode misalignment amount of the two points can be calculated. The average of the two first electrode misalignment amounts can be used as the first electrode misalignment amount between each circle of cathode electrode and the adjacent anode electrode, making the first electrode misalignment amount more accurate.

[0193] In some embodiments, as shown in FIG7, obtaining a plurality of first film widths corresponding to the first main body portion before the anode electrode 210 is wound, and a plurality of second film widths corresponding to the second main body portion before the cathode electrode 220 is wound, includes:

[0194] Step 701: Before the anode electrode, cathode electrode and separator are wound, a plurality of first sub-film widths corresponding to the first surface of the first main body, a plurality of second sub-film widths corresponding to the second surface of the first main body, a plurality of third sub-film widths corresponding to the first surface of the second main body, and a plurality of fourth sub-film widths corresponding to the second surface of the second main body are obtained.

[0195] The first surface is the surface facing the winding needle during the winding process, and the second surface is the surface away from the winding needle during the winding process.

[0196] In this embodiment, as mentioned above, both surfaces of the anode electrode 210 include a first main body portion of the anode film layer, and both surfaces of the cathode electrode 220 include a second main body portion of the cathode film layer. Based on this, two line-scan cameras can be respectively used to image the two surfaces, namely the first surface and the second surface, for the anode electrode 210 and the cathode electrode 220. The first surface can be the surface facing the winding needle 310 during the winding process, and the second surface can be the surface facing away from the winding needle 310 during the winding process.

[0197] As shown in Figure 2, the first camera 410 can take pictures of the first surface of the anode plate, the second camera 420 can take pictures of the second surface of the anode plate, the third camera 430 can take pictures of the first surface of the cathode plate, and the fourth camera 440 can take pictures of the second surface of the cathode plate.

[0198] Before the anode electrode 210 and the cathode electrode 220 are wound, multiple first sub-film widths corresponding to the first surface of the first main body, multiple second sub-film widths corresponding to the second surface of the first main body, multiple third sub-film widths corresponding to the first surface of the second main body, and multiple fourth sub-film widths corresponding to the second surface of the second main body can be obtained.

[0199] In other words, the first film width may include a first sub-film width and a second sub-film width, wherein the first sub-film width is the film width of the first surface of the anode electrode, and the second sub-film width is the film width of the second surface of the anode electrode. The second film width may include a third sub-film width and a fourth sub-film width, wherein the third sub-film width is the film width of the first surface of the cathode electrode, and the fourth sub-film width is the film width of the second surface of the cathode electrode.

[0200] In this embodiment, since there may be some deviations in the film widths of the two surfaces of the electrode, multiple first sub-film widths corresponding to the first surface of the anode electrode, multiple second sub-film widths corresponding to the second surface of the anode electrode, multiple third sub-film widths corresponding to the first surface of the cathode electrode, and multiple fourth sub-film widths corresponding to the second surface of the cathode electrode can be obtained separately. This can improve the accuracy of the film width data of the electrode, thereby improving the accuracy of the misalignment of the second electrode, and ultimately improving the reliability of the cell testing results.

[0201] In some embodiments, as shown in FIG8, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and the first electrode misalignment includes:

[0202] Step 801: Determine the second electrode misalignment between the first cathode electrode and the first inner anode electrode based on the fourth film width of the first cathode electrode, the third film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0203] Step 802: Determine the second electrode misalignment between the first cathode electrode and the first outer anode electrode based on the fourth film width of the first cathode electrode, the third film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0204] The third film width is the minimum value between the first and second sub-film widths at the same length position on the anode electrode, and the fourth film width is the maximum value between the third and fourth sub-film widths at the same length position on the cathode electrode.

[0205] In this embodiment, referring to Figure 3, the first surface of the first ring of cathode electrode is adjacent to the second surface of the first ring of anode electrode, and the second surface of the first ring of cathode electrode is adjacent to the second surface of the second ring of anode electrode. However, at the same location on the anode electrode 210 and the cathode electrode 220, there may be slight deviations in the film width data of the first and second surfaces.

[0206] In some embodiments, the average membrane width of two surfaces at the same location can be used as the membrane width at that location.

[0207] In other examples, the minimum of the first and second sub-film widths at the same length position of the anode electrode 210 can be taken as the film width of the anode electrode 210 at that length position, i.e., the third film width. Similarly, the maximum of the third and fourth sub-film widths at the same length position of the cathode electrode 220 can be taken as the film width of the cathode electrode 220 at that length position, i.e., the fourth film width. In this way, suitable film widths can be selected from the film widths of the two surfaces of the anode electrode 210 and cathode electrode 220 as the film width data for the anode electrode 210 and cathode electrode 220, and used in the subsequent calculation of the second electrode misalignment, thus simplifying the amount of calculation data.

[0208] The second electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101 can be calculated based on the fourth film width of the first cathode electrode 2201, the third film width of the first inner anode electrode 2101, and the first electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101. Similarly, the second electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102 can be calculated based on the fourth film width of the first cathode electrode 2201, the third film width of the first outer anode electrode 2102, and the first electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102.

[0209] In this embodiment, the film width at a given location can be determined by the larger of the film widths on the two surfaces of the cathode electrode 220 at the same position, and the film width at a given location can be determined by the smaller of the film widths on the two surfaces of the anode electrode 210 at the same position. Thus, the difference between the first and second film widths at that location can be less than or equal to the actual difference, and the subsequently calculated misalignment of the second electrode can be less than or equal to the actual misalignment. This simplifies the calculation of data while reducing the risk of missed detections.

[0210] In some embodiments, as shown in FIG8, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and the first electrode misalignment includes:

[0211] Step 803: Determine the second electrode misalignment between the first cathode electrode and the first inner anode electrode based on the third sub-film width of the first cathode electrode, the second sub-film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0212] Step 804: Determine the second electrode misalignment between the first cathode electrode and the first outer anode electrode based on the fourth sub-film width of the first cathode electrode, the first sub-film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0213] In this embodiment, as mentioned above, the first surface of the first ring of cathode electrode is adjacent to the second surface of the first ring of anode electrode, and the second surface of the first ring of cathode electrode is adjacent to the second surface of the second ring of anode electrode. However, at the same location on the anode and cathode electrodes, the film width data of the first and second surfaces may have slight deviations.

[0214] Based on this, the accurate misalignment of the second electrode between the first cathode electrode 2201 and the first inner anode electrode 2101 can be calculated directly from the width of the third sub-film on the first surface of the first cathode electrode 2201, the width of the second sub-film on the second surface of the first inner anode electrode 2101, and the misalignment of the first electrode between the first cathode electrode 2201 and the first inner anode electrode 2101.

[0215] The accurate amount of the second electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102 can be calculated directly based on the width of the fourth sub-film on the second surface of the first cathode electrode 2201, the width of the first sub-film on the first surface of the first outer anode electrode 2102, and the amount of first electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102.

[0216] In this embodiment, the film width data corresponding to the surfaces adjacent to the cathode electrode 220 and the anode electrode 210 can be used to calculate the misalignment of the second electrode between them, which improves the accuracy of the misalignment of the second electrode.

[0217] In some embodiments, as shown in FIG8, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and the first electrode misalignment includes:

[0218] Step 805: Determine the second electrode misalignment between the first cathode electrode and the first inner anode electrode based on the fourth film width of the first cathode electrode, the second sub-film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0219] Step 806: Determine the second electrode misalignment between the first cathode electrode and the first outer anode electrode based on the fourth film width of the first cathode electrode, the first sub-film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0220] The fourth film width is the maximum value of the third and fourth sub-film widths at the same length position of the cathode electrode.

[0221] In this embodiment, the maximum value of the third and fourth sub-film widths at the same length position of the cathode electrode 220 can be used as the film width of the cathode electrode at that length position, i.e., the fourth film width. For the anode electrode 210, the film width of its surface adjacent to the cathode electrode 220 can be directly used. Thus, a suitable film width can be selected from the film widths of the two surfaces of the cathode electrode 220 as the film width data for that cathode electrode 220, while the film width of the actual surface of the anode electrode 210 adjacent to the cathode electrode 220 can be used as the film width data for that anode electrode, participating in the subsequent calculation of the second electrode misalignment. This simplifies the amount of calculation data while maintaining accuracy.

[0222] The accurate misalignment of the second electrode between the first cathode electrode 2201 and the first inner anode electrode 2101 can be calculated based on the fourth film width of the first cathode electrode 2201, the second sub-film width of the first inner anode electrode 2101, and the first electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101. Similarly, the accurate misalignment of the second electrode between the first cathode electrode 2201 and the first outer anode electrode 2102 can be calculated based on the fourth film width of the first cathode electrode 2201, the first sub-film width of the first outer anode electrode 2102, and the first electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102.

[0223] In this embodiment, the film width at a given position can be determined by the larger of the film widths on the two surfaces of the cathode electrode 220 at the same location. Then, the misalignment of the second electrode at that position can be calculated by combining the film widths on the surfaces of the actual adjacent anode electrodes at that position. This approach can simultaneously meet the dual requirements of accuracy and low computational cost.

[0224] In some embodiments, as shown in FIG8, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and the first electrode misalignment includes:

[0225] Step 807: Determine the second electrode misalignment between the first cathode electrode and the first inner anode electrode based on the third sub-film width of the first cathode electrode, the third film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode.

[0226] Step 808: Determine the second electrode misalignment between the first cathode electrode and the first outer anode electrode based on the fourth sub-film width of the first cathode electrode, the third film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

[0227] The third membrane width is the minimum value between the first and second sub-membrane widths at the same length position on the anode electrode.

[0228] In this embodiment, the minimum value between the first sub-film width and the second sub-film width at the same length position of the anode electrode 210 can be used as the film width of the anode electrode 210 at that length position, i.e., the third film width. For the cathode electrode 220, the film width of its surface adjacent to the anode electrode 210 can be directly used. Thus, a suitable film width can be selected from the film widths of the two surfaces of the anode electrode 210 as the film width data for that anode electrode 210, while the film width of the actual surface of the cathode electrode 220 adjacent to the anode electrode 210 can be used as the film width data for that cathode electrode 220, participating in the subsequent calculation of the second electrode misalignment. This simplifies the amount of calculation data while maintaining accuracy.

[0229] The accurate amount of the second electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101 can be calculated based on the third sub-film width of the first cathode electrode 2201, the third film width of the first inner anode electrode 2101, and the first electrode misalignment between the first cathode electrode 2201 and the first inner anode electrode 2101.

[0230] Similarly, the accurate second electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102 can be calculated based on the fourth sub-film width of the first cathode electrode 2201, the third film width of the first outer anode electrode 2102, and the first electrode misalignment between the first cathode electrode 2201 and the first outer anode electrode 2102.

[0231] In this embodiment, the smaller value of the film width of the two surfaces of the anode electrode 210 at the same position can be used to determine the film width at that position. Then, the film width of the actual adjacent cathode electrode 220 at that position can be combined to calculate the misalignment of the second electrode at that position, which can simultaneously meet the dual requirements of accuracy and low computational data.

[0232] In some embodiments, as shown in FIG9, each first film width is associated with the length information of the anode electrode, and each second film width is associated with the length information of the cathode electrode.

[0233] Determining the second film width of the first cathode electrode from a plurality of second film widths, and determining the first film width of the first inner anode electrode and the first film width of the first outer anode electrode from a plurality of first film widths, includes:

[0234] Step 901: Determine the second film width of the first cathode electrode from the multiple second film widths based on the length information of the cathode electrode associated with the multiple second film widths and the number of layers of the first cathode electrode.

[0235] Step 902: Based on the length information of the anode plates associated with the multiple first film widths and the number of layers of the first cathode plate, determine the first film width of the first inner ring anode plate and the first film width of the first outer ring anode plate from the multiple first film widths.

[0236] In this embodiment, as mentioned above, multiple first film widths with fixed length intervals on the anode electrode 210 and multiple second film widths with fixed length intervals on the cathode electrode 220 can be obtained. Therefore, each first film width is associated with the length information of the anode electrode 210, and each second film width is associated with the length information of the cathode electrode 220.

[0237] The second film width of the first cathode electrode 2201 can be determined from multiple second film widths based on the number of layers of the first cathode electrode 2201 and the length information of the cathode electrodes associated with multiple second film widths. For example, a correspondence between the number of layers of the cathode electrode and the electrode length information can be established in advance. Based on the number of layers of the first cathode electrode 2201, the length information corresponding to the first cathode electrode 2201 can be matched from the correspondence, and then the second film width associated with this length information can be determined as the second film width of the first cathode electrode 2201.

[0238] Based on the number of concentric rings of the first cathode electrode 2201 and the length information of the anode electrodes associated with multiple first film widths, the first film width of the first inner ring anode electrode 2101 and the first film width of the first outer ring anode electrode 2102 can be determined from multiple first film widths. For example, a correspondence between the number of concentric rings of the cathode electrode and the length information of its adjacent anode electrodes can be established in advance. Based on the number of concentric rings of the first cathode electrode 2201, the length information corresponding to the first inner ring anode electrode 2101 and the first outer ring anode electrode 2102 can be directly matched from the correspondence. Therefore, the first film width associated with the length information corresponding to the first inner ring anode electrode 2101 can be determined as the first film width of the first inner ring anode electrode 2101, and the first film width associated with the length information corresponding to the first outer ring anode electrode 2102 can be determined as the first film width of the first outer ring anode electrode 2102.

[0239] The correspondence between the number of coils of the anode electrode and the length information of the anode electrode can also be established in advance. Based on the number of coils of the first cathode electrode 2201, the number of coils of the first inner anode electrode 2101 and the first outer anode electrode 2102 can be determined first. Then, the length information corresponding to the first inner anode electrode 2101 and the first outer anode electrode 2102 can be matched from the correspondence. Then, the first film width associated with the length information corresponding to the first inner anode electrode 2101 can be determined as the first film width of the first inner anode electrode 2101, and the first film width associated with the length information corresponding to the first outer anode electrode 2102 can be determined as the first film width of the first outer anode electrode 2102.

[0240] In this embodiment, the film width data corresponding to the electrode length can be matched according to the number of layers as the film width data corresponding to the current layer of electrode. The misalignment of the second electrode between the current layer of cathode electrode and its adjacent inner and outer anode electrodes is calculated, which improves the accuracy of the film width data and thus improves the accuracy of the misalignment of the second electrode.

[0241] In some embodiments, determining the second film width of the first cathode electrode from a plurality of second film widths based on the number of layers of the first cathode electrode and the length information of the cathode electrodes associated with the plurality of second film widths includes:

[0242] The following information is obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate.

[0243] The diameter of the first cathode electrode is determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode electrode, the thickness of the cathode electrode, the thickness of the diaphragm, the first gap, and the second gap.

[0244] The length of the cathode corresponding to the first cathode is determined based on the diameter of the first cathode.

[0245] The second film width of the first cathode electrode is determined from the multiple second film widths based on the length information of the cathode electrode associated with the multiple second film widths and the length of the cathode electrode.

[0246] In this embodiment, the coil diameter, anode plate thickness, cathode plate thickness, diaphragm thickness, first gap between the diaphragm and adjacent anode plates, and second gap between the diaphragm and adjacent cathode plates can be obtained.

[0247] Understandably, in some examples, the diameter of the first cathode electrode 2201 can refer to the diameter from the center of the cell to the first surface of the first cathode electrode 2201. Alternatively, the diameter from the center of the cell to the first or second surface of the first cathode electrode 2201 can be flexibly selected based on the film width data of the first or second surface to be used.

[0248] The diameter of the first cathode electrode 2201 can be determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode electrode, the thickness of the cathode electrode, the thickness of the diaphragm, the first gap, and the second gap. The formula for calculating the diameter of the first surface of the first cathode electrode 2201 is shown in formula (1):

[0249] D0+L0+(2T1+4T2+2T3+4G)*(n-1) (1)

[0250] The formula for calculating the diameter of the second surface of the first cathode electrode 2201 can be shown in formula (2):

[0251] D0+L0+2T1+(2T1+4T2+2T3+4G)*(n-1) (2)

[0252] Where D0 is the diameter of the winding needle; L0 is the first thickness of the innermost diaphragm and adhesive paper; T1 is the thickness of the anode plate; T2 is the thickness of the diaphragm; T3 is the thickness of the cathode plate; and G is the total thickness of the first gap and the second gap.

[0253] The cathode electrode length corresponding to the first cathode electrode 2201 can be determined based on its diameter. For example, the cathode electrode length corresponding to the first cathode electrode 2201 within the total cathode electrode length can be determined using a table showing the correspondence between cathode electrode diameters and cathode electrode lengths. For instance, if the total length is l1, the cathode electrode length corresponding to the first ring of cathode electrodes can be (0-l). 11 ].

[0254] Based on the length of the cathode electrode, the second film width whose length information is within the length range of the cathode electrode can be determined from the length information of multiple cathode electrodes associated with the second film width, and used as the second film width of the first cathode electrode 2201.

[0255] In this embodiment, the diameter of each turn of the cathode electrode can be calculated based on the thickness of each layer of winding material, the first gap, and the second gap. Then, the electrode length corresponding to each turn of the cathode electrode can be determined based on the diameter, which lays the foundation for determining the second film width of each turn of the cathode electrode from multiple second film widths based on the length of this segment of the electrode.

[0256] In some embodiments, determining the length of the cathode corresponding to the first cathode based on the diameter of the first cathode includes:

[0257] The circumference of the first cathode electrode is determined based on its diameter.

[0258] The length of the cathode electrode corresponding to the first cathode electrode is determined by the sum of the circumference of the first cathode electrode and the circumferences of all cathode electrodes corresponding to the number of layers before the number of layers of the first cathode electrode.

[0259] In this embodiment, the perimeter of the first cathode electrode 2201 can be calculated based on the diameter of the first cathode electrode 2201; the length of the cathode electrode corresponding to the first cathode electrode 2201 can be calculated based on the perimeter of the first cathode electrode 2201 and the sum of the perimeters of all cathode electrodes corresponding to the number of layers before the number of layers of the first cathode electrode 2201.

[0260] For example, the circumference of the first ring of cathode plates is l. 11 The circumference of the second cathode electrode is l. 12 The circumference of the third cathode electrode is l. 13 …If the first cathode electrode 2201 is the first ring cathode electrode, then the sum of the circumferences of all the cathode electrodes corresponding to the ring numbers preceding the first cathode electrode 2201 is 0. In this case, the length of the cathode electrode corresponding to the first cathode electrode 2201 is (0, l). 11 If the first cathode electrode 2201 is the second-round cathode electrode, then the sum of the circumferences of all cathode electrodes corresponding to the number of rounds preceding the first cathode electrode 2201 is l. 11 At this time, the length of the cathode corresponding to the first cathode electrode 2201 is (l 11 , l 12 If the first cathode electrode 2201 is the third cathode electrode, then the sum of the circumferences of all cathode electrodes corresponding to the number of layers preceding the first cathode electrode 2201 is l. 11 +l 12 At this time, the length of the cathode corresponding to the first cathode electrode 2201 is (l 11 +l 12 , l 13 ].

[0261] In this embodiment, the circumference of each ring of cathode electrode can be calculated based on the diameter. Combined with the total circumference of the previous rings, the electrode length corresponding to each ring of cathode electrode can be determined, which lays the foundation for determining the second film width of each ring of cathode electrode from multiple second film widths based on the electrode length.

[0262] In some embodiments, determining the second film width of the first cathode electrode from a plurality of second film widths based on the length information of the cathode electrode associated with a plurality of second film widths and the length of the cathode electrode includes:

[0263] Determine at least one fifth film width whose length information is within the length of the cathode electrode from a plurality of second film widths;

[0264] The average value of at least one fifth film width is determined as the second film width of the first cathode electrode.

[0265] In this embodiment, the number of second film widths whose length information is within the length of the cathode electrode can be one or more. All second film widths whose length information is within the length of the cathode electrode are selected from the multiple second film widths to obtain at least one fifth film width. At least one fifth film width can be the second film width related to the cathode electrode ring.

[0266] In some examples, the maximum value can be selected from at least one fifth film width as the second film width of that loop of cathode electrode. In another example, since the battery cell is cylindrical after winding, when detecting the misalignment of the first electrode by X-ray, the diameter of any angle in each loop of cathode electrode may be used as the cross-sectional line of the cross-sectional image. Based on this, in order to reduce the risk of inaccurate results for the misalignment of the second electrode due to the deviation between the position of the film width data and the position of obtaining the misalignment of the first electrode, the average value of at least one fifth film width can also be determined as the second film width of the first cathode electrode 2201.

[0267] In this embodiment, if there is more than one second film width within the length of each cathode electrode, the average value can be calculated as the second film width of that cathode electrode. In this way, the second film width of each cathode electrode can be standardized, which indirectly improves the robustness of the data and thus improves the reliability of the cell testing results.

[0268] In some embodiments, determining the first film width of the first inner ring anode and the first film width of the first outer ring anode from a plurality of first film widths based on the length information of the anode sheets associated with a plurality of first film widths and the number of rings of the first cathode sheet includes:

[0269] The following information is obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate.

[0270] Based on the number of layers of the first cathode electrode, determine the number of layers of the first inner anode electrode and the number of layers of the first outer anode electrode;

[0271] The diameter of the first inner ring anode plate is determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap of the first inner ring anode plate. The diameter of the first outer ring anode plate is determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap of the first outer ring anode plate.

[0272] The length of the anode plate corresponding to the first inner ring anode plate is determined based on the diameter of the first inner ring anode plate, and the length of the anode plate corresponding to the first outer ring anode plate is determined based on the diameter of the first outer ring anode plate.

[0273] Based on the anode length corresponding to the first inner anode sheet, the anode length corresponding to the first outer anode sheet, and the length information of the anode sheets associated with multiple first film widths, the first film width of the first inner anode sheet and the first film width of the first outer anode sheet are determined from the multiple first film widths.

[0274] In this embodiment, the following can be obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate.

[0275] Understandably, in some examples, the diameter of any anode electrode ring can refer to the diameter from the center of the cell to the first surface of the anode electrode ring. Alternatively, the diameter from the center of the cell to the first or second surface of the anode electrode ring can be flexibly selected based on the film width data of the first or second surface to be used.

[0276] The number of layers in the first inner anode plate 2101 and the first outer anode plate 2102 can be determined based on the number of layers in the first cathode plate 2201. For example, if the number of layers in the first cathode plate 2201 is 1, then the number of layers in the first inner anode plate 2101 is 1, and the number of layers in the first outer anode plate 2102 is 2.

[0277] The diameter of the first inner ring anode plate 2101 can be determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap of the first inner ring anode plate 2101. Similarly, the diameter of the first outer ring anode plate 2102 can be determined based on the number of coils, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap of the first outer ring anode plate 2102. The formula for calculating the diameter of the first surface of any ring anode plate is shown in formula (3).

[0278] D0+L0+2T1+2T2+2G+(2T1+4T2+2T3+4G)*(n-1) (3)

[0279] The formula for calculating the diameter of the second surface of any anode electrode is shown in formula (4):

[0280] D0+L0+2T1+2T2+2G+2T3+(2T1+4T2+2T3+4G)*(n-1) (4)

[0281] Where D0 is the diameter of the winding needle; L0 is the first thickness of the innermost diaphragm and adhesive paper; T1 is the thickness of the anode plate; T2 is the thickness of the diaphragm; T3 is the thickness of the cathode plate; and G is the total thickness of the first gap and the second gap.

[0282] The length of the anode plate corresponding to the first inner anode plate 2101 can be determined based on the diameter of the first inner anode plate 2101, and the length of the anode plate corresponding to the first outer anode plate 2102 can be determined based on the diameter of the first outer anode plate 2102.

[0283] For example, the anode electrode lengths of the first inner ring anode electrode 2101 and the first outer ring anode electrode 2102 within the total anode electrode length can be determined according to the correspondence table between the diameter and length of the anode electrode. For instance, if the total length is l2, the cathode electrode length corresponding to the first ring of cathode electrodes can be (0-l). 21 ].

[0284] Based on the length of the anode corresponding to the first inner anode 2101, the first film width whose length information falls within the length range of the anode 2101 can be determined from the length information of multiple anodes associated with the first film width, and this first film width can be used as the first film width of the first inner anode 2101. Similarly, based on the length of the anode corresponding to the first outer anode 2102, the first film width whose length information falls within the length range of the anode 2102 can be determined from the length information of multiple anodes associated with the first film width, and this first film width can be used as the first film width of the first outer anode 2102.

[0285] In this embodiment, the diameters of the inner and outer anode plates can be calculated based on the thickness of each layer of winding material, the first gap, and the second gap. Then, the corresponding electrode lengths of the inner and outer anode plates can be determined based on the diameters, laying the foundation for determining the first film widths of the inner and outer anode plates from multiple first film widths based on the electrode length.

[0286] In some embodiments, determining the anode length corresponding to the first inner ring anode sheet based on the diameter of the first inner ring anode sheet, and determining the anode length corresponding to the first outer ring anode sheet based on the diameter of the first outer ring anode sheet, includes:

[0287] The circumference of the first inner anode plate is determined based on the diameter of the first inner anode plate.

[0288] The circumference of the first outer ring anode plate is determined based on the diameter of the first outer ring anode plate;

[0289] The length of the anode corresponding to the first inner ring anode is determined by the sum of the circumference of the first inner ring anode and the circumference of the anode corresponding to all the rings before the first inner ring anode.

[0290] The length of the anode corresponding to the first outer ring anode is determined by the sum of the circumference of the first outer ring anode and the circumference of all anodes corresponding to the number of rings before the number of rings of the first outer ring anode.

[0291] In this embodiment, the circumference of the first inner anode plate 2101 can be calculated based on its diameter, and the circumference of the first outer anode plate 2102 can be calculated based on its diameter. The length of the anode plate corresponding to any given anode plate is calculated by summing the circumferences of the anode plates corresponding to all the anode plates preceding that anode plate.

[0292] For example, the circumference of the first anode plate is l. 21 The circumference of the second anode plate is l. 22 The circumference of the third anode plate is l. 23 …If the first inner anode plate 2101 is the first ring anode plate, and the first outer anode plate 2102 is the second ring anode plate, then the sum of the circumferences of the anode plates corresponding to all ring numbers preceding the number of rings in the first inner anode plate 2101 is 0, and the sum of the circumferences of the anode plates corresponding to all ring numbers preceding the number of rings in the first outer anode plate 2102 is 1. 21 At this time, the length of the anode plate corresponding to the first inner ring anode plate 2101 is (0, l) 21 The length of the anode plate corresponding to the first outer ring anode plate 2102 is (l 21 , l 21 If the first inner anode plate 2101 is the second anode plate and the first outer anode plate 2102 is the third anode plate, then the sum of the circumferences of all anode plates corresponding to the number of layers preceding the first inner anode plate 2101 is l. 21 The sum of the circumferences of all the anode plates corresponding to the number of layers before the first outer anode plate 2102 is l. 21 +l 22 At this time, the length of the anode plate corresponding to the first inner ring anode plate 2101 is (l 11 , l 21 The length of the anode plate corresponding to the first outer ring anode plate 2102 is (l 21 +l 22 , l 23 ].

[0293] In this embodiment, the circumference of the inner and outer anode plates can be calculated based on their diameters. Combined with the total circumference of the previous layers of the inner and outer anode plates, the lengths of the plates corresponding to the inner and outer anode plates can be determined respectively. This lays the foundation for determining the first film width of the inner and outer anode plates from multiple first film widths based on the length of the plate segment.

[0294] In some embodiments, determining the first film width of the first inner ring anode and the first film width of the first outer ring anode from a plurality of first film widths, based on the length information of anode sheets associated with a plurality of first film widths, and the anode sheet length corresponding to the first inner ring anode and the anode sheet length corresponding to the first outer ring anode, includes:

[0295] Determine at least one sixth film width whose length information is within the length of the anode corresponding to the first inner ring anode sheet from among a plurality of first film widths, and determine at least one seventh film width whose length information is within the length of the anode corresponding to the first outer ring anode sheet from among a plurality of first film widths;

[0296] The average value of at least one sixth film width is determined as the first film width of the first inner ring anode sheet, and the average value of at least one seventh film width is determined as the first film width of the first outer ring anode sheet.

[0297] In this embodiment, the number of first film widths whose length information falls within the length of the anode electrode can be one or more. All first film widths whose length information falls within the length of the anode electrode corresponding to the first inner anode electrode 2101 and the anode electrode corresponding to the first outer anode electrode 2102 are selected to obtain at least one sixth film width and at least one seventh film width. The at least one sixth film width can be the first film width related to the first inner anode electrode 2101, and the at least one seventh film width can be the first film width related to the first outer anode electrode 2102.

[0298] In some examples, the maximum value from at least a sixth film width and at least a seventh film width can be selected as the first film width of the first inner anode electrode 2101 and the first film width of the first outer anode electrode 2102, respectively. In another example, since the battery cell is cylindrical after winding, when detecting the misalignment of the first electrode by X-ray, the diameter of any angle in each anode electrode can be used as the cross-sectional line of the cross-sectional image. Based on this, in order to reduce the risk of inaccurate results for the misalignment of the second electrode due to the deviation between the position of the film width data and the position of obtaining the misalignment of the first electrode, the average value of at least a sixth film width can also be determined as the first film width of the first inner anode electrode 2101, and the average value of at least a seventh film width can be determined as the first film width of the first outer anode electrode 2102.

[0299] In this embodiment, if there is more than one first film width within the length of each anode electrode, the average value can be calculated as the first film width of that anode electrode. In this way, the first film width of each anode electrode can be standardized, which indirectly improves the robustness of the data and thus improves the reliability of the cell testing results.

[0300] In some embodiments, as shown in FIG10, determining the second electrode misalignment based on a plurality of first film widths, a plurality of second film widths, and the first electrode misalignment includes:

[0301] Step 1001: For each loop of cathode electrode, subtract the second film width of the cathode electrode from the first film width of the adjacent anode electrode to obtain the first difference.

[0302] Step 1002: Subtract the first electrode misalignment amount between the cathode electrode and the adjacent anode electrode from the first difference to obtain the second electrode misalignment amount between the cathode electrode and the adjacent anode electrode.

[0303] In this embodiment, for each turn of the cathode electrode 220, a first difference can be calculated by subtracting the second film width of the cathode electrode 220 from the first film width of the adjacent anode electrode 210. This first difference can be the total electrode misalignment on the anode tab side and the cathode tab side after the cell 200 is wound.

[0304] Subtracting the first electrode misalignment between the cathode electrode 220 and the adjacent anode electrode 210 from the first difference yields the accurate second electrode misalignment between the cathode electrode 220 and the adjacent anode electrode 210.

[0305] In this embodiment, the total electrode misalignment on the anode tab side and cathode tab side after the cell 200 is wound can be calculated based on the first film width and the second film width. Then, combined with the first electrode misalignment, the accurate second electrode misalignment on the anode tab side can be calculated. Based on the accurate first electrode misalignment and second electrode misalignment, the reliability of the cell detection results can be improved.

[0306] In some embodiments, cell testing is performed based on the misalignment of the first electrode and the misalignment of the second electrode, including:

[0307] When both the misalignment of the first electrode and the misalignment of the second electrode are greater than a preset threshold, the cell is determined to meet the electrode alignment requirements. The preset threshold is the critical value at which the size of the first main body portion exceeding that of the second main body portion does not meet the electrode alignment requirements.

[0308] In this embodiment, the preset threshold can be a value pre-set based on experience or a value determined based on film width data. In some examples, the preset threshold corresponding to each loop of cathode electrode and the adjacent anode electrode can be the same value. For example, the average of multiple first film widths and multiple second film widths can be calculated, and the preset threshold is determined based on the average of the multiple first film widths and multiple second film widths. In other examples, the preset threshold corresponding to each loop of cathode electrode and the adjacent anode electrode can be different values. For example, the first film width of each loop of cathode electrode and the second film width of its adjacent anode electrode can be calculated, and the preset threshold corresponding to each loop of cathode electrode and the adjacent anode electrode is determined based on the first film width of each loop of cathode electrode and the second film width of its adjacent anode electrode. No specific limitations are imposed here.

[0309] The misalignment of the first and second electrodes can be compared with a preset threshold. If both the misalignment of the first and second electrodes are greater than the preset threshold, then the cell can be determined to meet the electrode alignment requirements. If the misalignment of the first or second electrode between any cathode electrode and its adjacent anode electrode is less than the preset threshold, then the cell can be considered not to meet the electrode contrast requirements.

[0310] In this embodiment, when both the misalignment of the first electrode and the misalignment of the second electrode are greater than a preset threshold, it is determined that the cell meets the electrode alignment requirements, thereby improving the cell yield.

[0311] As shown in Figures 2 and 12, this application embodiment also provides a battery cell testing system, including:

[0312] A winding machine 300 is used to include a winding needle 310 and an image acquisition mechanism 400. The winding needle 310 is used to wind a battery cell 200. The battery cell 200 includes an anode electrode 210, a cathode electrode 220, and a separator 230. The anode electrode 210, cathode electrode 220, and separator 230 are wound together. The anode electrode 210 includes a first main body portion with an anode film layer and an anode tab without an anode film layer. The cathode electrode 220 includes a second main body portion with a cathode film layer and a cathode tab without a cathode film layer. The image acquisition mechanism 400 is used to acquire multiple first film widths corresponding to the first main body portion before the anode electrode 210 is wound, and multiple second film widths corresponding to the second main body portion before the cathode electrode 220 is wound, and transmit the acquired multiple first film widths and multiple second film widths to a processor.

[0313] X-ray system 1201 is located downstream of winding machine 300 and is used to perform X-ray detection on battery cell 200 after winding, obtain the misalignment of first electrode, and transmit the misalignment of first electrode to processor.

[0314] The processor 1202 is connected to the image acquisition mechanism 400 and the X-ray system 1201 and is used to perform the above-described cell detection method.

[0315] Understandably, the winding machine 300 may include a winding needle 310 for winding the battery cell 200. The image acquisition mechanism 400 may include a camera and an image processor, such as data acquisition software, for processing the images acquired by the camera to obtain film width data. The X-ray system 1201 may include an X-ray device for taking cross-sectional images of the battery cell. In some examples, the X-ray system 1201 may also include an X-ray host computer for processing the cross-sectional images to obtain the first electrode misalignment amount.

[0316] In this embodiment, the first film width of the first main body portion of the anode electrode 210 with the anode film layer and the second film width of the second main body portion of the cathode electrode 220 with the cathode film layer can be obtained before winding. The first electrode misalignment on the cathode tab side obtained by X-ray detection of the battery cell 200 after winding can be obtained. Thus, the total electrode misalignment on the anode tab side and the cathode tab side after winding can be calculated based on the first film width and the second film width. Combined with the first electrode misalignment, the accurate second electrode misalignment on the anode tab side can be calculated. Battery cell detection based on the accurate first electrode misalignment and second electrode misalignment can improve the reliability of battery cell detection results.

[0317] In some embodiments, as shown in FIG12, the processor 1202 is further configured to:

[0318] The membrane width data and cell identifier are associated and stored. The membrane width data includes multiple first membrane widths and multiple second membrane widths of the cell corresponding to the cell identifier.

[0319] Based on the cell identifier, obtain the membrane width data associated with the cell.

[0320] Understandably, processor 1202 can be used to pre-store film width data acquired before winding. In some examples, processor 1202 can be an edge intelligent control platform.

[0321] In this embodiment, membrane width data and cell identifier can be stored in advance. Then, the membrane width data of the cell to be tested can be retrieved based on the cell identifier to calculate the misalignment of the second electrode, thus making the acquisition of membrane width data more flexible and intelligent during cell testing.

[0322] In some embodiments, as shown in Figures 2 and 12, the image acquisition mechanism 400 may include:

[0323] A first camera 410 is positioned facing the first surface of the anode electrode 210 before winding, for acquiring a first image of the first surface of the anode electrode 210 before winding.

[0324] The second camera 420 is positioned toward the second surface of the anode electrode 210 before winding, and is used to acquire a second image of the second surface of the anode electrode 210 before winding.

[0325] The third camera 430 is positioned facing the first surface of the cathode electrode 220 before winding, and is used to acquire a third image of the first surface of the cathode electrode 220 before winding.

[0326] A fourth camera 440 is positioned toward the second surface of the cathode electrode 220 before it is wound up, for acquiring a fourth image of the second surface of the cathode electrode 220 before it is wound up.

[0327] An image processor is configured to determine, based on a first image, a second image, a third image, and a fourth image, a plurality of first sub-film widths and a plurality of second sub-film widths of a first main body portion, and a plurality of third sub-film widths and a plurality of fourth sub-film widths of a second main body portion;

[0328] The first surface is the surface facing the winding needle 310 during the winding process, and the second surface is the surface away from the winding needle 320 during the winding process.

[0329] In this embodiment, since there may be some deviations in the film widths of the two surfaces of the electrode, multiple first sub-film widths corresponding to the first surface of the anode electrode, multiple second sub-film widths corresponding to the second surface of the anode electrode, multiple third sub-film widths corresponding to the first surface of the cathode electrode, and multiple fourth sub-film widths corresponding to the second surface of the cathode electrode can be obtained separately. This can improve the accuracy of the film width data of the electrode, thereby improving the accuracy of the misalignment of the second electrode, and ultimately improving the reliability of the cell testing results.

[0330] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by a computer program or instructions. These programs or instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0331] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for testing a battery cell, the battery cell comprising an anode electrode, a cathode electrode, and a separator, wherein the anode electrode, the cathode electrode, and the separator are wound together, the anode electrode comprising a first main body portion of an anode film layer and an anode tab without the anode film layer, and the cathode electrode comprising a second main body portion of a cathode film layer and a cathode tab without the cathode film layer; The method includes: Before the anode sheet, the cathode sheet and the diaphragm are wound, a plurality of first film widths corresponding to the first main body portion and a plurality of second film widths corresponding to the second main body portion are obtained; The first electrode misalignment amount is obtained by X-ray detection of the battery cell after winding. The first electrode misalignment amount is the size by which the first main body portion of the adjacent anode electrode portion of the cathode electrode exceeds the second main body portion of the cathode electrode portion on the side of the battery cell away from the anode tab. Based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment, the second electrode misalignment is determined. The second electrode misalignment is the dimension by which the first main body portion of the adjacent anode electrode of the cell extends beyond the second main body portion of the cathode electrode on the side of the cell closest to the anode tab.

2. The method according to claim 1, wherein, Each ring of the cathode electrode comprises an inner ring of anode electrodes and an outer ring of anode electrodes; The step of determining the second electrode misalignment based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment includes: The second film width of the first cathode electrode is determined from the plurality of second film widths, and the first film width of the first inner ring anode electrode and the first film width of the first outer ring anode electrode are determined from the plurality of first film widths, wherein the first cathode electrode is any ring of cathode electrode, and the first inner ring anode electrode and the first outer ring anode electrode are adjacent anode electrodes of the first cathode electrode; The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the second film width of the first cathode electrode, the first film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode. The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the second film width of the first cathode electrode, the first film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

3. The method according to claim 2, wherein, The step of obtaining the first electrode misalignment amount obtained by X-ray detection of the battery cell after winding includes: Obtain a cross-sectional image of the battery cell after winding is performed using X-ray inspection; Edge detection is performed on the cross-sectional image to obtain the first boundary of the first main body portion and the second boundary of the second main body portion on the side away from the anode tab; The misalignment of the first electrode is determined based on the interval between the first boundary and the second boundary.

4. The method according to claim 3, wherein, The step of determining the misalignment of the first electrode based on the interval between the first boundary and the second boundary includes: Obtain the first and second sub-boundary points belonging to the first cathode electrode on the second boundary, the third and fourth sub-boundary points belonging to the first inner anode electrode on the first boundary, and the fifth and sixth sub-boundary points belonging to the first outer anode electrode on the first boundary; wherein the first and second sub-boundary points, the third and fourth sub-boundary points, and the fifth and sixth sub-boundary points are symmetrically distributed along the central axis of the cell. Determine a first interval between the first sub-boundary point and the third sub-boundary point, a second interval between the second sub-boundary point and the fourth sub-boundary point, a third interval between the first sub-boundary point and the fifth sub-boundary point, and a fourth interval between the second sub-boundary point and the sixth sub-boundary point; The average of the first interval and the second interval is determined as the first electrode misalignment amount between the first cathode electrode and the first inner anode electrode; The average of the third interval and the fourth interval is determined as the first electrode misalignment amount between the first cathode electrode and the first outer anode electrode.

5. The method according to any one of claims 2 to 4, wherein, Each first film width is associated with the length information of the anode electrode, and each second film width is associated with the length information of the cathode electrode; The step of determining the second film width of the first cathode electrode from the plurality of second film widths, and determining the first film width of the first inner anode electrode and the first film width of the first outer anode electrode from the plurality of first film widths, includes: The second film width of the first cathode electrode is determined from the plurality of second film widths based on the length information of the cathode electrode associated with the plurality of second film widths and the number of layers of the first cathode electrode. Based on the length information of the anode sheet associated with the plurality of first film widths and the number of layers of the first cathode sheet, the first film width of the first inner ring anode sheet and the first film width of the first outer ring anode sheet are determined from the plurality of first film widths.

6. The method according to claim 5, wherein, The step of determining the second film width of the first cathode electrode from the plurality of second film widths based on the length information of the cathode electrode associated with the plurality of second film widths and the number of layers of the first cathode electrode includes: The following parameters are obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate. The diameter of the first cathode electrode is determined based on the number of coils of the first cathode electrode, the diameter of the coiled needle, the first thickness, the thickness of the anode electrode, the thickness of the cathode electrode, the thickness of the diaphragm, the first gap, and the second gap. The length of the cathode electrode corresponding to the first cathode electrode is determined based on the diameter of the first cathode electrode. The second film width of the first cathode electrode is determined from the plurality of second film widths based on the length information of the cathode electrode associated with the plurality of second film widths and the length of the cathode electrode.

7. The method according to claim 6, wherein, The step of determining the length of the cathode corresponding to the first cathode based on the diameter of the first cathode includes: The circumference of the first cathode electrode is determined based on its diameter. The length of the cathode electrode corresponding to the first cathode electrode is determined by the sum of the circumference of the first cathode electrode and the circumference of all cathode electrodes corresponding to the number of concentric circles before the number of concentric circles of the first cathode electrode.

8. The method according to claim 6 or 7, wherein, The step of determining the second film width of the first cathode electrode from the plurality of second film widths based on the length information of the cathode electrode associated with the cathode electrode length and the plurality of second film widths includes: Determine at least one fifth film width whose length information is within the length of the cathode electrode from the plurality of second film widths; The average value of the at least one fifth film width is determined as the second film width of the first cathode electrode.

9. The method according to any one of claims 5 to 8, wherein, The step of determining the first film width of the first inner ring anode and the first film width of the first outer ring anode from the plurality of first film widths based on the length information of the anode sheet associated with the plurality of first film widths and the number of rings of the first cathode sheet includes: The following parameters are obtained: the diameter of the winding needle corresponding to the battery cell, the first thickness of the separator and adhesive paper adjacent to the winding needle, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the separator, the first gap between the separator and the adjacent anode plate, and the second gap between the separator and the adjacent cathode plate. The number of layers of the first inner anode electrode and the number of layers of the first outer anode electrode are determined based on the number of layers of the first cathode electrode. The diameter of the first inner ring anode electrode is determined based on the number of coils of the first inner ring anode electrode, the diameter of the coiled needle, the first thickness, the thickness of the anode electrode, the thickness of the cathode electrode, the thickness of the diaphragm, the first gap, and the second gap. The diameter of the first outer ring anode plate is determined based on the number of coils of the first outer ring anode plate, the diameter of the coiled needle, the first thickness, the thickness of the anode plate, the thickness of the cathode plate, the thickness of the diaphragm, the first gap, and the second gap. The length of the anode corresponding to the first inner anode is determined based on the diameter of the first inner anode, and the length of the anode corresponding to the first outer anode is determined based on the diameter of the first outer anode. Based on the length information of the anode plates associated with the plurality of first film widths, and the anode plate lengths corresponding to the first inner ring anode plate and the first outer ring anode plate, the first film width of the first inner ring anode plate and the first film width of the first outer ring anode plate are determined from the plurality of first film widths.

10. The method according to claim 9, wherein, The step of determining the anode length corresponding to the first inner anode plate based on the diameter of the first inner anode plate, and determining the anode length corresponding to the first outer anode plate based on the diameter of the first outer anode plate, includes: The circumference of the first inner ring anode plate is determined based on the diameter of the first inner ring anode plate; The circumference of the first outer anode plate is determined based on the diameter of the first outer anode plate. The length of the anode corresponding to the first inner ring anode is determined by the sum of the circumference of the first inner ring anode and the circumference of all anodes corresponding to the number of rings before the number of rings of the first inner ring anode. The length of the anode corresponding to the first outer anode is determined by the sum of the circumference of the first outer anode and the circumferences of all anodes corresponding to the number of layers before the first outer anode.

11. The method according to claim 9 or 10, wherein, The step of determining the first film width of the first inner ring anode and the first film width of the first outer ring anode from the plurality of first film widths based on the length information of the anode plates associated with the plurality of first film widths, and the anode plate lengths corresponding to the first inner ring anode and the first outer ring anode, includes: Determine at least one sixth film width whose length information is within the length of the anode corresponding to the first inner ring anode sheet from the plurality of first film widths, and determine at least one seventh film width whose length information is within the length of the anode corresponding to the first outer ring anode sheet from the plurality of first film widths; The average value of the at least one sixth film width is determined as the first film width of the first inner ring anode sheet, and the average value of the at least one seventh film width is determined as the first film width of the first outer ring anode sheet.

12. The method according to any one of claims 2 to 11, wherein, Before winding the anode, cathode, and diaphragm, obtaining a plurality of first film widths corresponding to the first main body portion and a plurality of second film widths corresponding to the second main body portion includes: Before the anode electrode, the cathode electrode and the diaphragm are wound, a plurality of first sub-film widths corresponding to the first surface of the first main body, a plurality of second sub-film widths corresponding to the second surface of the first main body, a plurality of third sub-film widths corresponding to the first surface of the second main body, and a plurality of fourth sub-film widths corresponding to the second surface of the second main body are obtained. Wherein, the first surface is the surface facing the winding needle during the winding process, and the second surface is the surface away from the winding needle during the winding process.

13. The method according to claim 12, wherein, The step of determining the second electrode misalignment based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment includes: The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the fourth film width of the first cathode electrode, the third film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode. The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the fourth film width of the first cathode electrode, the third film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode. Wherein, the third film width is the minimum value of the first sub-film width and the second sub-film width at the same length position of the anode electrode, and the fourth film width is the maximum value of the third sub-film width and the fourth sub-film width at the same length position of the cathode electrode.

14. The method according to claim 12, wherein, The step of determining the second electrode misalignment based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment includes: The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the third sub-film width of the first cathode electrode, the second sub-film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode. The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the fourth sub-film width of the first cathode electrode, the first sub-film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode.

15. The method according to claim 12, wherein, The step of determining the second electrode misalignment based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment includes: The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the fourth film width of the first cathode electrode, the second sub-film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode. Based on the fourth film width of the first cathode electrode, the first sub-film width of the first outer ring anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer ring anode electrode, the second electrode misalignment between the first cathode electrode and the first outer ring anode electrode is determined. Wherein, the fourth film width is the maximum value of the third sub-film width and the fourth sub-film width at the same length position on the cathode electrode.

16. The method according to claim 12, wherein, The step of determining the second electrode misalignment based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment includes: The second electrode misalignment between the first cathode electrode and the first inner anode electrode is determined based on the third sub-film width of the first cathode electrode, the third film width of the first inner anode electrode, and the first electrode misalignment between the first cathode electrode and the first inner anode electrode. The second electrode misalignment between the first cathode electrode and the first outer anode electrode is determined based on the fourth sub-film width of the first cathode electrode, the third film width of the first outer anode electrode, and the first electrode misalignment between the first cathode electrode and the first outer anode electrode. The third film width is the minimum value between the first sub-film width and the second sub-film width at the same length position on the anode electrode.

17. The method according to any one of claims 1 to 16, wherein, The step of determining the second electrode misalignment based on the plurality of first film widths, the plurality of second film widths, and the first electrode misalignment includes: For each loop of cathode electrode, the first film width of the adjacent anode electrode is subtracted from the second film width of the cathode electrode to obtain the first difference. Subtracting the first electrode misalignment between the cathode electrode and the adjacent anode electrode from the first difference yields the second electrode misalignment between the cathode electrode and the adjacent anode electrode.

18. The method according to any one of claims 1 to 17, further comprising: If both the misalignment of the first electrode and the misalignment of the second electrode are greater than a preset threshold, the cell is determined to meet the electrode alignment requirements. The preset threshold is the critical value at which the size of the first main body portion exceeding that of the second main body portion does not meet the electrode alignment requirements.

19. A battery cell testing system, comprising: A winding machine, including winding needles and an image acquisition mechanism; The winding needle is used to wind the battery cell, which includes an anode electrode, a cathode electrode, and a separator. The anode electrode, the cathode electrode, and the separator are wound together. The anode electrode includes a first main body portion with an anode film layer and an anode tab without the anode film layer. The cathode electrode includes a second main body portion with a cathode film layer and a cathode tab without the cathode film layer. The image acquisition mechanism is used to acquire multiple first film widths corresponding to the first main body portion and multiple second film widths corresponding to the second main body portion before the anode electrode, the cathode electrode and the diaphragm are wound, and to transmit the acquired multiple first film widths and multiple second film widths to the processor. An X-ray system is located downstream of the winding machine to perform X-ray detection on the battery cell after winding, obtain the misalignment of the first electrode, and transmit the misalignment of the first electrode to the processor. A processor, connected to an image acquisition mechanism and an X-ray system, is used to perform the method as described in any one of claims 1 to 18.

20. The system according to claim 19, wherein, The processor is also used for: The membrane width data and cell identifier are associated and stored together. The membrane width data includes multiple first membrane widths and multiple second membrane widths of the cell corresponding to the cell identifier. Based on the cell identifier, obtain the film width data associated with the cell.

21. The system according to claim 19 or 20, wherein, The image acquisition mechanism includes: A first camera is positioned facing the first surface of the anode sheet before it is wound, for acquiring a first image of the first surface of the anode sheet before it is wound; A second camera, positioned facing the second surface of the anode sheet before winding, is used to acquire a second image of the second surface of the anode sheet before winding. A third camera is positioned facing the first surface of the cathode electrode before it is wound, for acquiring a third image of the first surface of the cathode electrode before it is wound. A fourth camera, positioned facing the second surface of the cathode electrode before winding, is used to acquire a fourth image of the second surface of the cathode electrode before winding. An image processor is configured to determine, based on the first image, the second image, the third image, and the fourth image, a plurality of first sub-film widths and a plurality of second sub-film widths of the first main body portion, and a plurality of third sub-film widths and a plurality of fourth sub-film widths of the second main body portion; Wherein, the first surface is the surface facing the winding needle during the winding process, and the second surface is the surface away from the winding needle during the winding process.

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