Method and apparatus for detecting a lamination-type electrode assembly

Abstract

The application relates to a detection method and a detection device for a lamination type electrode assembly, the electrode assembly comprising a positive electrode sheet and a negative electrode sheet, the detection method being used for detecting the dislocation amount of a positive electrode angle position of the positive electrode sheet relative to a corresponding negative electrode angle position of the negative electrode sheet, a coordinate equation is established through shooting at different positions and angles of the electrode assembly, a geometric equation is established in combination with the geometric characteristics of the positive electrode sheet, and the dislocation amount of the positive electrode angle position relative to the corresponding negative electrode angle position is obtained according to the coordinate equation and the geometric equation. Compared with the prior art, the detection method has high detection efficiency and small detection error.

Description

Technical Field

[0001] This application relates to the field of battery testing equipment technology, and in particular to a testing method and testing device for a stacked electrode assembly. Background Technology

[0002] Lithium-ion battery electrode components can be stacked structures. Stacked electrode components have high energy density, good power characteristics, and are not easily deformed after charging and discharging, making them widely used in the electric vehicle field. For stacked electrode components, the negative electrode must completely cover the positive electrode, and the offset of the positive electrode relative to the negative electrode must not exceed the design requirements; otherwise, it will lead to problems such as short circuits and lithium plating. Therefore, it is necessary to detect the offset of the positive electrode relative to the negative electrode. Summary of the Invention

[0003] This application provides a detection method and device for stacked electrode assemblies, which can reduce the number of detections and improve detection efficiency.

[0004] The first aspect of this application provides a method for detecting a stacked electrode assembly, the electrode assembly including a positive electrode and a negative electrode, the detection method being used to detect the misalignment of the positive electrode angle of the positive electrode relative to the negative electrode angle of the negative electrode, the detection method including:

[0005] Capture the positive and corresponding negative polar angles, record the shooting angles, measure the distance between the positive and negative polar angles, and establish coordinate equations;

[0006] Measure the geometric characteristics of the positive electrode and establish the geometric equation;

[0007] The misalignment is obtained by combining the coordinate equation and the geometric equation.

[0008] Existing detection methods require taking two images at each positive and corresponding negative pole angle, with different angles, and establishing separate coordinate systems and equations to obtain the misalignment amount for each positive pole angle individually. The processes for obtaining the misalignment amount for each positive pole angle are unrelated. The detection method of this application, however, establishes a unified coordinate system for each positive and corresponding negative pole angle during the imaging process. It introduces the geometric features of the positive electrode sheet and establishes geometric equations describing the relative positional relationship of each positive pole angle, thus linking the coordinates of each positive pole angle. This eliminates the need to take images for each positive and corresponding negative pole angle individually, and also eliminates the need to take two images for each positive and corresponding negative pole angle. Therefore, compared to existing technologies, the detection method of this application requires fewer images, improving detection efficiency. Furthermore, because a unified coordinate system is established during the detection process, and the coordinates of each positive and corresponding negative pole angle are linked together, the accuracy of the jointly obtained misalignment amount is higher.

[0009] In one possible detection method, the positive and negative electrodes are rectangular. Any two opposite sides or adjacent sides of the positive or negative electrode are selected as the reference for the shooting angle, and the shooting angles of each positive electrode angle and the corresponding negative electrode angle are adjusted.

[0010] The detection method of this application is used to detect rectangular positive and negative electrode sheets. It utilizes two opposite or adjacent sides of one electrode sheet as a reference for the shooting angle. Furthermore, compared to existing detection methods that select a shooting angle reference by photographing only one positive and corresponding negative angle, this method only requires selecting two geometrically related sides as shooting angle references during the detection process, reducing the number of times a shooting angle reference is selected and improving shooting efficiency. Moreover, because a relatively uniform shooting angle is used as the reference, the shooting angle error is small, resulting in higher accuracy in obtaining the misalignment amount of the positive electrode angle.

[0011] In one possible detection method, the coordinates of the i-th positive polar angle are (x... i y i The coordinates of the i-th negative polar angle are (X... i Y i The misalignment of the i-th positive pole angle relative to the corresponding negative pole angle is (Δx). i Δy i );

[0012] The number of shots (j≤2) for a single positive pole angle and its corresponding negative pole angle, with the edge of the negative pole piece 12 as the reference for the shooting angle, is recorded as follows: and / or

[0013] The distance between the i-th positive pole angle and the corresponding negative pole angle is measured as l. i ;

[0014] Establish coordinate equations:

[0015] Establish a geometric equation: the sum of the x-coordinates of the two positive polar angles on any side of the positive electrode is equal to the sum of the x-coordinates of the two positive polar angles on the opposite side.

[0016] Establish a geometric equation: the sum of the ordinates of the two positive pole angles on any side of the positive electrode is equal to the sum of the ordinates of the two positive pole angles on the opposite side.

[0017] Measure the actual dimensions of the two adjacent sides of the positive electrode, or, refer to the design dimensions of the two adjacent sides of the positive electrode, establish a geometric equation. The ratio of the difference in the ordinate of the two positive pole angles on any side of the positive electrode to the length h of that side is equal to the ratio of the difference in the abscissa of the two positive pole angles on the adjacent side to the length w of the adjacent side.

[0018] Compared to existing technologies that require two separate photographs and separate calculations at each positive pole angle of a rectangular positive electrode sheet, totaling eight photographs, the detection method of this application, by combining the geometric features of the rectangular positive electrode sheet and measuring its length and width dimensions, can establish geometric equations by combining the horizontal and vertical coordinates of each positive pole angle. This eliminates the need for eight photographs and eight coordinate equations to be established. Instead, it provides eight equations that can be used to solve for the misalignment of the horizontal and vertical coordinates at the four positive pole angles. Therefore, detection can be completed with at least five photographs, improving detection efficiency.

[0019] In one possible detection method, the electrode assembly also includes copper tabs, with the position of the positive and negative pole angles closest to the copper tabs being the first position, and the positions of the remaining positive pole angles and their corresponding negative pole angles being the second, third, and fourth positions, respectively.

[0020] In the first position, the shooting path does not coincide with the copper electrode tab, and the number of shots is one;

[0021] When the second, third, and fourth positions each require two shots,

[0022] In this detection method, the imaging path at the first position near the copper electrode tab does not coincide with the copper electrode tab, thus avoiding its influence, and only one image is captured, reducing detection error. At each of the other positions, at most two images are captured; that is, images may be omitted or captured only once at a certain position, resulting in a total of fewer than eight images and high detection efficiency. Furthermore, the angular difference between the two images taken at positions other than the first position is greater than or equal to 45°, which further reduces detection error.

[0023] In one possible detection method, at the second, third, and fourth positions, one position is captured twice, while the remaining positions are captured once.

[0024] In this detection method, an image is taken at a first position close to the copper electrode tab, with the shooting path not overlapping with the copper electrode tab to avoid interference. Only one image is taken, reducing detection error. Two positions (second, third, or fourth) are selected, each taking one image, and the remaining position is taken twice, with the angle difference between the two images greater than or equal to 45°. Therefore, this detection method requires a total of five images, compared to eight images in existing methods, resulting in higher detection efficiency. Furthermore, in this method, an angle difference of 45° or greater between two images taken at the same position minimizes detection error.

[0025] In one possible detection method, one of the second, third, and fourth positions is captured once, while the remaining positions are captured twice.

[0026] In this detection method, an image is taken at a first position close to the copper electrode tab, with the shooting path not coinciding with the copper electrode tab to avoid interference. Only one image is taken, reducing detection error. An image is taken once at one of the second, third, or fourth positions, and twice at the remaining two positions, with the angle difference between the two images at each position greater than or equal to 45°. Therefore, this detection method requires a total of six images, compared to eight images in existing methods, resulting in higher detection efficiency. In this method, an angle difference of 45° or greater at the same position minimizes detection error. Furthermore, adding one more image to the five images required to meet the detection conditions—that is, adding a set of sample data—further improves detection accuracy.

[0027] In one possible detection method, images are taken twice at each of the second, third, and fourth positions.

[0028] Compared to the eight images required in existing detection methods, the detection method of this application requires only six images, resulting in higher detection efficiency. Furthermore, by adding two more images to the five images required to meet the detection conditions, two more sets of sample data are generated, which further improves the detection accuracy.

[0029] In one possible detection method, at the second, third, and fourth positions, one position is captured zero times, while the remaining positions are captured twice.

[0030] Compared to existing detection methods that require eight images, the detection method in this application requires only six images, resulting in higher detection efficiency.

[0031] In one possible detection method, the electrode assembly further includes copper tabs. The positions of the positive and negative pole angles closest to the copper tabs are designated as the first position. The positions of the remaining positive pole angles and their corresponding negative pole angles are designated as the second, third, and fourth positions, respectively. At each of the second, third, and fourth positions, the images are taken twice.

[0032] Compared to existing detection methods, this method requires fewer than eight shots, resulting in higher detection efficiency. Furthermore, it avoids the first position close to the copper electrode tab, eliminating the need to select from the limited shooting angle range of the first position. Instead, it allows for flexible selection of shooting angles from three positions—the second, third, and fourth—that are not close to the copper electrode tab, thus improving the operability of the detection process.

[0033] In one possible detection method, one of the second, third, and fourth positions is captured once, while the other two positions are captured twice.

[0034] Compared to existing detection methods that require eight shots, the detection method in this application requires only five shots, resulting in higher detection efficiency. It avoids the first position close to the copper electrode tab and eliminates the need to select from the limited shooting angle range of the first position. The shooting angle can be flexibly selected from three positions—the second, third, and fourth positions—that are not close to the copper electrode tab, thus improving the operability of the detection process.

[0035] In one possible detection method, the number of shots at each of the second, third, and fourth positions is twice.

[0036] Compared to existing detection methods that require eight imaging sessions, this application's detection method requires only six, resulting in higher detection efficiency. It also avoids the first position close to the copper electrode, eliminating the need to choose from the limited imaging angles at that position. Instead, it allows for flexible selection of imaging angles from three positions—the second, third, and fourth—that are not close to the copper electrode, improving the operability of the detection process. Furthermore, by adding one more imaging session to the five required for meeting the detection conditions, an additional set of sample data is generated, further enhancing detection accuracy.

[0037] In one possible detection method, when j1+j2+j3+j4>5, the least squares method is used to obtain the misalignment of each positive pole angle relative to the corresponding negative pole angle.

[0038] When there are more than five sets of test sample data, the least squares method can be used to obtain the misalignment amount with smaller fitting error for the horizontal and vertical coordinates among the four positive polar angle positions.

[0039] The second aspect of this application provides a detection device that uses the detection method of the above-described stacked electrode assembly to detect the misalignment of each positive electrode angle relative to the corresponding negative electrode angle. The detection device includes a ray emitter and a detector, wherein the ray emitter is used to emit test light and the detector is used to detect the test light.

[0040] This application utilizes X-rays as the test light of the ray machine, which allows for more accurate detection of the positive electrode angle of the positive electrode and the negative electrode angle of the negative electrode.

[0041] In one possible design, the detection device also includes an adjustment mechanism for adjusting the position and angle of the ray and detector relative to the electrode assembly.

[0042] The built-in adjustment device allows users to easily adjust the position and angle of the X-ray machine and detector, providing greater flexibility and improving detection efficiency.

[0043] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0044] Figure 1 This is a partial structural schematic diagram of the electrode assembly provided in the embodiments of this application;

[0045] Figure 2 Provided for this application Figure 1 A schematic diagram of the detection method for the electrode assembly;

[0046] Figure 3 A schematic diagram of the detection method provided in this application in a first specific embodiment;

[0047] Figure 4 A schematic diagram of the detection method provided in this application in a second specific embodiment;

[0048] Figure 5 A schematic diagram of the detection method provided in this application in a third specific embodiment;

[0049] Figure 6 This is a schematic diagram illustrating the impact of the difference in the two imaging angles on the detection error;

[0050] Figure 7 A schematic diagram of the detection method provided in this application in the fourth specific embodiment;

[0051] Figure 8 for Figure 3 , Figure 4 , Figure 7 The detection error effect diagram of the detection method in China.

[0052] Figure label:

[0053] 1-Electrode assembly;

[0054] 11-Positive electrode plate;

[0055] 111-Aluminum tab;

[0056] 12-Negative electrode;

[0057] 121-Copper electrode ear;

[0058] 13 - First position;

[0059] 14 - Second position;

[0060] 15 - Third position;

[0061] 16 - Fourth position;

[0062] 2-ray device;

[0063] 3-Detector.

[0064] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0067] 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.

[0068] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0069] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0070] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0071] From the perspective of market development, power batteries, as the main energy storage device, are being used more and more widely. They are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in military equipment and aerospace and other fields. As the application fields of power batteries continue to expand, the performance requirements for them are also constantly increasing.

[0072] The inventors have noticed that in stacked electrode assemblies, there is a phenomenon of positive electrode offset relative to negative electrode, which has a significant impact on the performance of the electrode assembly. It is necessary to determine the size of this offset using testing equipment to verify the manufacturing quality of the electrode assembly. To detect the amount of offset between the positive and negative electrodes, the inventors discovered that an X-ray emitting device can be used to image the stacked electrode assembly. Since the positive and negative electrodes in existing stacked electrode assemblies are mostly rectangular, the measurement mainly focuses on the lateral and longitudinal offset between the four positive pole angles (vertices) of the positive electrode and the corresponding negative pole angles (vertices) of the negative electrode. However, existing detection methods require two images of each positive pole angle of the positive electrode at different angles, thus establishing two coordinate equations to obtain the lateral and longitudinal offset of a positive pole angle relative to its corresponding negative pole angle. For rectangular positive and negative electrodes, a total of eight images are required to calculate the misalignment of the four positive electrode corners with respect to the lateral and longitudinal directions, resulting in low detection efficiency.

[0073] Based on the above considerations, and to improve detection efficiency, the inventors, after in-depth research, proposed a detection method and device for stacked electrode assemblies. By adjusting the angle of the detection device, at most two images are taken at each positive electrode corner of the positive electrode sheet. A coordinate equation is constructed, utilizing the rectangular geometric features of the positive electrode sheet and incorporating its length and width dimensions, to establish a geometric equation that yields the misalignment of the positive electrode corner relative to the corresponding negative electrode corner in the negative electrode sheet. Compared to existing detection technologies, the detection method for stacked electrode assemblies in this application reduces the number of images taken and improves detection efficiency. The detection device in this application allows users to easily adjust the shooting angle using the detection method, further improving detection efficiency.

[0074] Since stacked electrode assemblies can be used in electrical devices such as vehicles, ships, or aircraft, the testing method and testing device of this application for stacked electrode assemblies can be used to improve testing efficiency in the process of testing the manufacturing quality of electrode assemblies.

[0075] In this application, the electrode assembly can be applied to lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited thereto.

[0076] The electrode assembly mentioned in the embodiments of this application is a single physical module used in battery modules to provide higher voltage and capacity. The first aspect of this application provides a method for detecting a stacked electrode assembly; please refer to... Figures 1-2 As shown, electrode assembly 1 consists of a positive electrode 11, a negative electrode 12, and a separator (not shown). Electrode assembly 1 mainly operates by the movement of metal ions between the positive electrode 11 and the negative electrode 12. The positive electrode 11 includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the current collector without the positive active material layer protrudes beyond the current collector with the positive active material layer, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode 12 includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the current collector without the negative active material layer protrudes beyond the current collector with the negative active material layer, serving as the negative electrode tab. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. To ensure that a large current can pass through without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together. The diaphragm material can be PP or PE, etc. This application is mainly used for testing stacked electrode assemblies 1, but is not limited to this.

[0077] like Figures 1-2 As shown, the detection method is used to detect the misalignment of the positive electrode angle of the positive electrode 11 relative to the negative electrode angle of the negative electrode 12. The detection method includes:

[0078] S1: Take pictures of the positive and corresponding negative pole angles, record the shooting angles, measure the distance between the positive and negative pole angles, and establish coordinate equations;

[0079] S2: Measure the geometric characteristics of the positive electrode 11 and establish the geometric equation;

[0080] S3: The misalignment is obtained by combining the coordinate equation and the geometric equation.

[0081] In this embodiment, in step S1, the detection device simultaneously captures images of the positive angle of the positive electrode 11 and the negative angle of the negative electrode 12 in the electrode assembly 1. The positive electrode 11 and the negative electrode 12 can be similar polygons, with each positive angle in the positive electrode 11 corresponding to a negative angle in the negative electrode 12. However, the positive electrode 11 and the negative electrode 12 may not be similar polygons; therefore, it is necessary to determine each positive angle and its corresponding negative angle to facilitate the identification of the subject during subsequent imaging. After capturing and imaging all corresponding positive and negative angles, the distance between the captured positive and negative angles is measured, and a coordinate equation is established. In establishing the coordinate equation, a specific angle in either the positive electrode 11 or the negative electrode 12 is selected as the origin. Using a rectangular or polar coordinate system, the relative positional relationship between each positive and negative angle is constructed. The edge of the positive electrode 11 or the negative electrode 12 is used as the reference for adjusting the shooting angle, for example... Figure 1 The shooting path shown by the dashed line forms an angle with the wide side of the positive electrode 11, with the wide side of the positive electrode 11 serving as the starting side of the angle (the zero point of the shooting angle). A coordinate equation can be established for each shot. In step S2, the geometric features of the positive electrode 11, such as side length and the angle between adjacent sides, are obtained through measurement or other methods. These features are then combined with the coordinate information of each positive and negative electrode angle to establish a geometric equation. In step S3, the misalignment of each positive electrode angle of the positive electrode 11 relative to the corresponding negative electrode angle in the negative electrode 12 is obtained by combining the coordinate equation from step S1 and the geometric equation from step S2. In the subsequent description of this embodiment, the positive electrode 11 and the negative electrode 12 are mainly described as similar polygons.

[0082] Existing detection methods require taking two images at a single positive pole angle and its corresponding negative pole angle, with different angles each time. A separate coordinate system and equation are then established to obtain the misalignment for each positive pole angle individually, and the processes for obtaining the misalignment for each positive pole angle are unrelated. The detection method of this application, however, establishes a unified coordinate system for each positive pole angle and its corresponding negative pole angle during the imaging process. It introduces the geometric features of the positive pole plate 11 and establishes geometric equations describing the relative positional relationship of each positive pole angle, thus linking the coordinates of each positive pole angle. This eliminates the need to take images for each positive pole angle and its corresponding negative pole angle, and also eliminates the need to take two images for each positive pole angle and its corresponding negative pole angle. Therefore, compared to existing detection methods, the detection method of this application requires fewer images, improving detection efficiency. Furthermore, because a unified coordinate system is established during the detection process, and the coordinates of each positive pole angle and its corresponding negative pole angle are linked together, the accuracy of the misalignment obtained through the combined coordinate and geometric equations is higher.

[0083] In a specific detection method, such as Figures 1-2As shown, the positive electrode 11 and the negative electrode 12 are rectangular. In step S1, any two opposite sides or adjacent sides of the positive electrode 11 or the negative electrode 12 are selected as the reference for the shooting angle, and the shooting angles of each positive electrode angle and the corresponding negative electrode angle are adjusted.

[0084] In this embodiment, the positive electrode 11 and the negative electrode 12 are in a similar rectangular relationship, with the area of ​​the negative electrode 12 being larger than that of the positive electrode 11, and the negative electrode 12 covering the positive electrode 11. In step S1, either any two opposite sides of the positive electrode 11 can be selected as the shooting angle reference, or either any two opposite sides of the negative electrode 12 can be selected as the shooting angle reference, or either either adjacent sides of the negative electrode 12 can be selected as the shooting angle reference. The required shooting angle reference is selected according to the actual detection needs.

[0085] The detection method of this application is used to detect rectangular positive electrode plates 11 and negative electrode plates 12. It utilizes two opposite or adjacent sides of one of the electrodes as a reference for the shooting angle. Furthermore, compared to existing detection methods that require selecting a reference for a shooting angle by photographing a single positive and corresponding negative electrode angle, this method only requires selecting two geometrically related sides as the shooting angle reference during the detection process. For example, two opposite and parallel sides or two adjacent and perpendicular sides of either the rectangular positive electrode plate 11 or the rectangular negative electrode plate 12. This reduces the number of times a shooting angle reference needs to be selected, improving shooting efficiency. Furthermore, because a relatively uniform shooting angle is used as the reference, the relative error of each shooting angle is small, resulting in higher accuracy in obtaining the misalignment amount of the positive electrode angle.

[0086] Specifically, such as Figures 1-2 As shown, the coordinates of the i-th positive polar angle are (x... i y i The coordinates of the i-th negative polar angle are (X... i Y i The misalignment of the i-th positive pole angle relative to the corresponding negative pole angle is (Δx). i Δy i Step S1 includes:

[0087] S11: The number of shots j≤2 for a single positive pole angle and its corresponding negative pole angle, with the edge of the negative pole piece 12 as the reference for the shooting angle, and the shooting angle is recorded as follows. and / or

[0088] S12: Measure the distance l between the i-th positive polar angle and the corresponding negative polar angle. i ;

[0089] S13: Establish coordinate equations:

[0090] Step S2 includes:

[0091] S21: Establish a geometric equation that the sum of the abscissas of the two positive pole angles on any side of the positive pole plate 11 is equal to the sum of the abscissas of the two positive pole angles on the opposite side.

[0092] S22: Establish a geometric equation that the sum of the ordinates of the two positive pole angles on any side of the positive pole plate 11 is equal to the sum of the ordinates of the two positive pole angles on the opposite side.

[0093] S23: Measure the actual dimensions of the two adjacent sides of the positive electrode 11, or, refer to the design dimensions of the two adjacent sides of the positive electrode 11, establish a geometric equation. The ratio of the difference in the ordinate of the two positive pole angles on any side of the positive electrode 11 to the length h of that side is equal to the ratio of the difference in the abscissa of the two positive pole angles on the adjacent side to the length w of the adjacent side.

[0094] In this embodiment, as Figures 1-3 As shown, the coordinates of the i-th positive polar angle are set as (x... i y i Let the coordinates of the i-th negative polar angle be (X). i Y i The misalignment of the coordinates of the i-th positive polar angle relative to the coordinates of the corresponding negative polar angle is (Δx). i Δy i In this embodiment, the misalignment of the positive electrode angle relative to the negative electrode angle is detected using the negative electrode plate 12 as a reference to establish a rectangular coordinate system, and the edge of the negative electrode plate 12 is used as the reference for the shooting angle. In step S11, the number of shots for a single positive electrode angle and its corresponding negative electrode angle is limited to a maximum of two. When the number of shots for a single positive electrode angle and its corresponding negative electrode angle is two, the two shooting angles are different, i.e. In step S12, the distance between the i-th positive pole angle and the corresponding negative pole angle is measured to be l. i .like Figure 2 and Figure 3 The positive electrode position at the upper right corner of the positive electrode 11 is shown. Using the wide side of the negative electrode 12 as the shooting angle reference, the angle between the direction of the shooting light and the wide side of the negative electrode 12 is... The distance between the positive and negative pole angles is l1. Given l1 as a known quantity, establish the coordinate equation. Then, take a second picture at a different angle at the same positive pole angle, or take a second picture at any other positive pole angle. Similarly, construct a second coordinate equation. Depending on the actual detection situation, five to seven pictures can be taken to establish the coordinate equations for five pictures as shown in equations (1)-(5). In addition, when the long side of the negative pole piece 12 is used as the reference for the shooting angle, the coordinate equation is adjusted to This embodiment will be described in detail below using the wide side of the negative electrode 12 as the reference for the shooting angle. During the shooting process, the shooting order of the four positive electrode angles of the positive electrode 11 is not limited, nor is the order of shooting the positive electrode angle twice or once. Before, after, or during the shooting of the four positive electrode angles of the positive electrode 11, step S2 can be completed, such as in steps S21 and S22. Using the geometric feature that opposite sides of the rectangle are parallel and equal, the horizontal and vertical coordinates of the four positive electrode angles are summed accordingly, and the geometric equations of equations (6)-(7) are one embodiment. Regarding step S22, the distance between two adjacent sides of the positive electrode 11 is measured, that is, the actual values ​​of the length dimension h and the width dimension w, or the design values ​​of the length dimension h and the width dimension w are directly referenced (the actual value deviation is a small amount relative to the design value). Using the geometric feature that the adjacent sides of the rectangle are perpendicular to each other and the included angles relative to the negative electrode 12 are the same, the geometric equation shown in equation (8) is constructed as one embodiment. Finally, based on the equations shown in equations (1) to (8), the misalignment of each positive pole angle relative to the corresponding negative pole angle with respect to the horizontal and vertical coordinates is obtained.

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] x1 + x2 = x3 + x4 (6)

[0101] y1+y4=y2+y3 (7)

[0102] (y4-y3) / w=(x3-x2) / h (8)

[0103] Compared to existing detection methods that require taking two separate photos and solving each coordinate equation at each positive pole corner of the rectangular positive electrode 11, totaling eight photos, the detection method of this application, by combining the geometric features of the rectangular shape of the positive electrode 11 and measuring the length h and width w, can combine the horizontal and vertical coordinates of each positive pole corner to establish a geometric equation. This eliminates the need for taking eight photos and establishing eight coordinate equations. Instead, it provides eight equations that can be used to solve for the misalignment of the horizontal and vertical coordinates at the four positive pole corners. Therefore, detection can be completed with at least five photos, improving detection efficiency.

[0104] The detection methods in this application are mainly divided into two categories, the difference being whether the image is taken near the copper tab 121. The first type of detection method, which involves taking an image near the copper tab 121, is described below.

[0105] Specifically, please refer to Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown. The electrode assembly 1 also includes a copper tab 121. The position of the positive and negative electrode angles closest to the copper tab 121 is the first position 13. The positions of the remaining positive electrode angles and their corresponding negative electrode angles are the second position 14, the third position 15, and the fourth position 16, respectively. Step S11 includes:

[0106] S111: At the first position 13, the shooting path does not coincide with the copper electrode 121, and the shooting number is one;

[0107] S112: When the number of shots at each of the second position 14, the third position 15, and the fourth position 16 is two,

[0108] In this embodiment, the execution order of steps S11 and S22 is not limited during the shooting process, nor is the shooting order of the first position 13, the second position 14, the third position 15, and the fourth position 16 limited. Please refer to... Figures 3-4 As shown, the aluminum tab 111 of the positive electrode 11 and the copper tab 121 of the negative electrode 12 are on the same side. Please refer to [reference needed]. Figure 5 As shown, the aluminum tab 111 of the positive electrode 11 and the copper tab 121 of the negative electrode 12 are not on the same side. When the detection device uses X-ray imaging, the copper tab 121 has a strong X-ray absorption capacity, making it difficult for the detector 3 to form a clear image, resulting in low detection accuracy. Furthermore, the path of the X-ray passing through the positive electrode angle cannot coincide with the copper tab 121. Figure 1 As shown, the range of possible shooting angles at the first position 13 near the copper electrode 121 is less than 45°. If the difference between two shooting angles at the same position is less than 45°, the detection error of shooting twice at a single position is larger than the detection error of shooting once. Figure 6As shown, when the angle difference between two shots taken at a single position is 15°, 30°, 45°, and 60°, the detection errors for the horizontal coordinate misalignment Δx and the vertical coordinate misalignment Δy of a single positive pole angle are calculated. Therefore, the position of the copper tab 121 affects the shooting angle of the detection device. Only one shot can be taken within the shooting range of the first position 13 near the copper tab 121, and the shooting angle is recorded during the shot. Then measure the distance l1 between the positive and negative polar angles at the first position 13, and establish the corresponding coordinate equation. Then, take at most two photos at each of the remaining positions. When taking two photos at a single position, the angle difference between the two photos should be greater than or equal to 45°. Figure 1 and Figure 3 As shown, the two shooting angles at position 16 in the fourth position,

[0109] In the detection method of this application, the imaging path at the first position 13 near the copper electrode 121 does not coincide with the copper electrode 121, is not affected by the copper electrode 121, and is only captured once, reducing detection error. At each of the other positions, at most two images are captured; that is, for a certain position, no image is captured or only one image is captured. The total number of images is less than eight, resulting in high detection efficiency. Furthermore, according to... Figure 6 As can be seen from the illustration of the influence of the difference in the two imaging angles on the detection error in the existing detection technology, the detection method of this application can reduce the detection error by taking two pictures at a position other than the first position 13 with an angle difference greater than or equal to 45°.

[0110] Please refer to Figure 1 and Figure 3 As shown, in step S112, in the second position 14, the third position 15 and the fourth position 16, one position is photographed twice, and the other positions are photographed once.

[0111] In this embodiment, one of the following locations—second position 14, third position 15, or fourth position 16—is selected based on the actual detection situation. Two images are taken at this position, with the angle difference between the two images being greater than or equal to 45°. Then, one image is taken at the remaining two positions. Combined with step S111, a total of five images are taken. During the image capture process, the order of images taken at the first position 13, second position 14, third position 15, or fourth position 16 is not limited, nor is the order of images taken at positions requiring two captures versus positions requiring one capture.

[0112] This embodiment is the first type of the aforementioned first-class detection method. Because it combines with step S111, the image is taken at the first position 13 near the copper electrode 121, and the shooting path does not coincide with the copper electrode 121, it is not affected by the copper electrode 121, and only one image is taken, reducing detection error. Two positions are selected from the second position 14, the third position 15, or the fourth position 16, each taking one image, and the remaining position is taken twice, with the angle difference between the two images being greater than or equal to 45°. Therefore, this embodiment requires a total of five images, compared to eight images in existing detection methods, resulting in higher detection efficiency. Furthermore, according to... Figure 6 As shown in the diagram illustrating the impact of the difference in two imaging angles on the detection error in the existing detection technology, in this embodiment, if the difference in two shooting angles at one position is greater than or equal to 45°, the detection error is small.

[0113] Please refer to Figure 1 and Figure 4 As shown, in step S112, in the second position 14, the third position 15 and the fourth position 16, one position is photographed once and the other positions are photographed twice.

[0114] In this embodiment, one of the three positions (second position 14, third position 15, and fourth position 16) that are not close to the copper electrode tab 121 is selected to complete one shot, and two shots are taken at the remaining two positions, with the angle difference between the two shots at a single position being greater than or equal to 45°. Combined with step S111, a total of six shots are taken. During the shooting process, the shooting order at the first position 13, second position 14, third position 15, or fourth position 16 is not limited, nor is the shooting order limited between positions requiring two shots and positions requiring one shot.

[0115] This embodiment is the second type of the first type of detection method described above. Because it combines with step S111, the image is taken at the first position 13 near the copper electrode 121, and the shooting path does not coincide with the copper electrode 121, it is not affected by the copper electrode 121, and only one image is taken, reducing detection error. One image is taken at each of the second position 14, the third position 15, or the fourth position 16, and two images are taken at the remaining two positions, with the angle difference between the two images at each position being greater than or equal to 45°. Therefore, this embodiment requires a total of six images, compared to eight images in existing detection methods, resulting in higher detection efficiency. Furthermore, according to... Figure 6 As illustrated in the diagram of the impact of the difference in two imaging angles on detection error in existing detection technologies, the detection method of this application results in a smaller detection error when the difference in the two images taken at the same location is greater than or equal to 45°. Furthermore, by adding one more image to the five images required to meet the detection conditions, i.e., adding a set of sample data, the detection accuracy can be further improved.

[0116] Step S112 also includes another detection method (not shown in the figure), in which each position 14, 15 and 16 are photographed twice.

[0117] In this embodiment, at three positions—second position 14, third position 15, and fourth position 16—that are not close to the copper electrode tab 121, two shots are taken at each position, and the angle difference between the two shots at a single position is greater than or equal to 45°. Combined with step S111, a total of seven shots are taken. During the shooting process, the shooting order of the first position 13, second position 14, third position 15, or fourth position 16 is not limited.

[0118] This embodiment is the third of the first type of detection methods described above. The effect of this detection method is briefly described here. Compared with the existing detection methods that require eight shots, this embodiment only requires six shots, which is more efficient. In addition, by adding two more shots to the five shots required to meet the detection conditions, two more sets of sample data are added, which can further improve the detection accuracy.

[0119] In step S112, in the second position 14, the third position 15 and the fourth position 16, one position is photographed zero times, and the other positions are photographed twice (not shown in the figure).

[0120] In this embodiment, two positions are selected from the three positions (second position 14, third position 15, and fourth position 16) that are not close to the copper electrode tab 121 for shooting. Each position is shot twice, and the angle difference between the two shots at a single position is greater than or equal to 45°. Combined with step S111, a total of five shots are taken. During the shooting process, the shooting order of the first position 13, second position 14, third position 15, or fourth position 16 is not limited.

[0121] This embodiment is the fourth of the first type of detection methods described above. The effect of this detection method is briefly described here. Compared with the existing detection methods that take eight pictures, this embodiment takes only five pictures, resulting in high detection efficiency.

[0122] In the above embodiments, a photo is taken once at the first position 13 near the copper electrode 121. In the embodiments described below, the photo is not taken at the first position 13 near the copper electrode 121, which is the second type of detection method.

[0123] Specifically, please refer to Figure 1 and Figure 7 As shown, the electrode assembly 1 also includes a copper tab 121. The position of the positive and negative electrode angles closest to the copper tab 121 is the first position 13. The positions of the remaining positive electrode angles and their corresponding negative electrode angles are the second position 14, the third position 15, and the fourth position 16, respectively. Step S11 also includes:

[0124] S113: When the number of shots at each of the second position 14, the third position 15, and the fourth position 16 is two,

[0125] In this embodiment, instead of taking a picture at the first position 13 near the copper electrode 121, pictures are taken at three positions: the second position 14, the third position 15, and the fourth position 16, which are not near the copper electrode 121. Each position is photographed at most twice, and the angle difference between the two photographs at a single position is greater than or equal to 45°. During the shooting process, the shooting order at the second position 14, the third position 15, or the fourth position 16 is not limited.

[0126] The second type of detection method has the same effect as the first type of detection method. Compared with the existing detection method, it takes less than eight shots, which is more efficient. In addition, it avoids the first position 13 that is close to the copper electrode 121. It does not need to be selected within the limited shooting angle range of the first position 13. The shooting angle can be flexibly selected from the three positions of the second position 14, the third position 15 and the fourth position 16 that are not close to the copper electrode 121, which improves the operability of the detection process.

[0127] Please refer to Figure 1 and Figure 7 As shown, in step S113, the second type of detection method can be specifically described as follows: in the second position 14, the third position 15 and the fourth position 16, one position is captured once, and the other two positions are captured twice.

[0128] In this embodiment, one of the following positions—second position 14, third position 15, or fourth position 16—that is not close to the copper electrode 121 is selected based on the actual detection situation. A single image is taken at this position, and then two images are taken at each of the remaining two positions. The angle difference between the two images at a single position is greater than or equal to 45°, for a total of five images. The order of images taken at the second position 14, third position 15, or fourth position 16 is not limited, nor is the order of images taken at positions requiring two images versus positions requiring one image.

[0129] Compared to existing detection methods that require eight shots, the detection method in this embodiment only requires five shots, resulting in higher detection efficiency. It avoids the first position 13, which is close to the copper electrode 121, and does not require selection within the limited shooting angle range of the first position 13. The shooting angle can be flexibly selected from three positions: the second position 14, the third position 15, and the fourth position 16, which are not close to the copper electrode 121, thus improving the operability of the detection process.

[0130] In step S113, the second type of detection method can also be specifically described as follows: in the second position 14, the third position 15 and the fourth position 16, the number of shots at each position is twice (not shown in the figure).

[0131] In this embodiment, at the second position 14, the third position 15, or the fourth position 16, which are not close to the copper electrode tab 121, two shots are taken at each position, and the angle difference between the two shots at a single position is greater than or equal to 45°, for a total of six shots. The shooting order at the second position 14, the third position 15, or the fourth position 16 is not limited during the shooting process.

[0132] Compared to existing detection methods that require eight imaging sessions, the detection method in this embodiment requires only six imaging sessions, resulting in higher detection efficiency. It also avoids the first position 13, which is close to the copper electrode 121, eliminating the need to select within the limited imaging angle range of the first position 13. The imaging angle can be flexibly selected from three positions—the second position 14, the third position 15, and the fourth position 16—that are not close to the copper electrode 121, improving the operability of the detection process. Furthermore, by adding one more imaging session to the five imaging sessions required to meet the detection conditions, an additional set of sample data is added, further improving detection accuracy. In the above embodiment, step S3 includes:

[0133] S31: When j1+j2+j3+j4>5, the least squares method is used to obtain the displacement of each positive pole angle relative to the corresponding negative pole angle.

[0134] In this embodiment, when the number of coordinate equations is greater than five, that is, the number of equations in the coordinate equations and geometric equations is greater than the number of misalignments of the horizontal and vertical coordinates in the four positive polar angles, it is difficult to directly obtain the misalignments of the horizontal and vertical coordinates in the four positive polar angles. It is necessary to use the least squares method to perform curve fitting on more than five sets of sample data to obtain the misalignments of the horizontal and vertical coordinates in the four positive polar angles and reduce the error in the fitting process.

[0135] In this embodiment, when there are more than five sets of test sample data, the least squares method can be used to obtain the misalignment amount with smaller fitting error for the horizontal and vertical coordinates among the four positive polar angle positions.

[0136] The second aspect of this application provides a detection device, such as... Figure 2 As shown, the detection device uses the detection method of the above-mentioned stacked electrode assembly to detect the misalignment of each positive electrode angle relative to the corresponding negative electrode angle. The detection device includes a ray 2 and a detector 3. The ray 2 is used to emit test light, and the detector 3 is used to detect the test light.

[0137] In this embodiment, the test light is X-ray.

[0138] In this embodiment, X-rays are used as the test light for the ray machine 2, which makes the detection of the positive pole angle of the positive electrode 11 and the negative pole angle of the negative electrode 12 more accurate.

[0139] Specifically, please refer to Figures 1-2 As shown, the detection device also includes an adjustment device (not shown in the figure), which is used to adjust the position and angle of the ray generator 2 and the detector 3 relative to the electrode assembly 1.

[0140] In this embodiment, the adjustment device can move the ray generator 2 and the detector 3 to any one of the first position 13, the second position 14, the third position 15, and the fourth position 16. Using the long or wide side of either the positive electrode 11 or the negative electrode 12 in the electrode assembly 1 as the reference (angle zero point) for the shooting angle, the adjustment device can adjust the angle of the ray generator 2 and the detector 3 relative to the positive electrode 11 or the negative electrode 12. Therefore, after each shooting, the position and / or angle of the ray generator 2 and the detector 3 can be changed using the adjustment device.

[0141] In this embodiment, the adjustment device allows the user to easily adjust the position and angle of the ray generator 2 and the detector 3, providing greater flexibility and improving detection efficiency.

[0142] In one implementation scheme, please refer to Figures 1-2 As shown, the position and angle of the ray generator 2 and detector 3 relative to the electrode assembly 1 are adjusted using the adjustment device in the detection device, and irradiation and imaging are performed using the ray generator 2 and detector 3 in the detection device. At most one image is taken at the first position 13 of the positive electrode 11, and at most two images are taken at each of the second position 14, the third position 15, or the fourth position 16. When two images are taken at a single position, the angle difference between the two images is greater than or equal to 45°. After each image is taken, the ray generator 2 and detector 3 are readjusted using the detection device so that the ray generator 2 and detector 3 can perform subsequent images at different angles at the same position or at different positions. Each time an image is taken, a coordinate equation as shown in equations (1) to (5) can be constructed. Then, combining the length dimension h and width dimension w of the positive electrode 11 and the rectangular geometric features, the geometric equations as shown in equations (6) to (8) are constructed. According to the equations shown in equations (1) to (8), the misalignment amount of each positive electrode angle of the positive electrode 11 relative to the corresponding negative electrode angle in the negative electrode 12 is obtained. When the number of shots exceeds five, meaning the number of coordinate equations exceeds five, the least squares method is then used to obtain the misalignment for the four positive polar angles. For example... Figure 8 As shown, compared with existing detection methods, the detection method of this application has higher detection accuracy.

[0143] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for detecting a stacked electrode assembly, the electrode assembly (1) comprising a positive electrode (11) and a negative electrode (12), the detection method being used to detect the misalignment of the positive electrode angle of the positive electrode (11) relative to the negative electrode angle of the negative electrode (12), characterized in that, The detection method includes: The positive and negative pole angles are photographed, the shooting angles are recorded, the distance between the positive and negative pole angles is measured, and a coordinate equation is established. Measure the geometric characteristics of the positive electrode (11) and establish the geometric equation; The misalignment is obtained by combining the coordinate equation and the geometric equation. The geometric equation includes the fact that the sum of the abscissas of the two positive pole angles on any side of the positive pole sheet (11) is equal to the sum of the abscissas of the two positive pole angles on the opposite side. The geometric equation also includes the fact that the sum of the ordinates of the two positive pole angles on any side of the positive pole sheet (11) is equal to the sum of the ordinates of the two positive pole angles on the opposite side.

2. The detection method for the stacked electrode assembly according to claim 1, characterized in that, The positive electrode (11) and the negative electrode (12) are rectangular. In the detection method: Select either two opposite sides or two adjacent sides of the positive electrode (11) or the negative electrode (12) as the reference for the shooting angle, and adjust the shooting angle of each positive electrode angle position and the corresponding negative electrode angle position.

3. The detection method for the stacked electrode assembly according to claim 2, characterized in that, The coordinates of the i-th positive polar angle are The coordinates of the i-th negative pole angle are The misalignment of the i-th positive pole angle position relative to the corresponding negative pole angle position is In the detection method: Number of shots for a single positive pole angle and the corresponding negative pole angle Using the edge of the negative electrode (12) as the reference for the shooting angle, the shooting angle is recorded as follows: and / or , ; The distance between the i-th positive pole angle and the corresponding negative pole angle is measured as follows: ; Establish the coordinate equations: and / or ; Measure the actual dimensions of the two adjacent sides of the positive electrode (11), or, refer to the design dimensions of the two adjacent sides of the positive electrode (11), establish the geometric equation. The ratio of the difference between the ordinates of the two positive electrode angles on any side of the positive electrode (11) to the length h of that side is equal to the ratio of the difference between the abscissas of the two positive electrode angles on the adjacent side to the length w of the adjacent side.

4. The detection method for the stacked electrode assembly according to claim 3, characterized in that, The electrode assembly (1) further includes a copper tab (121). The position of the positive and negative electrode angles closest to the copper tab (121) is the first position (13). The positions of the remaining positive and negative electrode angles are the second position (14), the third position (15), and the fourth position (16), respectively. In the detection method: At the first position (13), the shooting path does not coincide with the copper electrode (121), and the number of shots is one; When the number of shots at each of the second position (14), the third position (15), and the fourth position (16) is two, .

5. The detection method for the stacked electrode assembly according to claim 4, characterized in that, In the second position (14), the third position (15) and the fourth position (16), one position is photographed twice, and the other positions are photographed once.

6. The detection method for the stacked electrode assembly according to claim 4, characterized in that, In the second position (14), the third position (15) and the fourth position (16), one position is photographed once, and the other positions are photographed twice.

7. The detection method for the stacked electrode assembly according to claim 4, characterized in that, In the second position (14), the third position (15) and the fourth position (16), each position is photographed twice.

8. The detection method for the stacked electrode assembly according to claim 4, characterized in that, In the second position (14), the third position (15) and the fourth position (16), one position is photographed zero times, and the other positions are photographed twice.

9. The detection method for the stacked electrode assembly according to claim 3, characterized in that, The electrode assembly (1) further includes a copper tab (121). The position of the positive and negative electrode angles closest to the copper tab (121) is the first position (13). The positions of the remaining positive and negative electrode angles are the second position (14), the third position (15), and the fourth position (16), respectively. In the detection method: When the number of shots at each of the second position (14), the third position (15), and the fourth position (16) is two, .

10. The detection method for the stacked electrode assembly according to claim 9, characterized in that, In the second position (14), the third position (15) and the fourth position (16), one position is photographed once, and the other two positions are photographed twice.

11. The detection method for the stacked electrode assembly according to claim 9, characterized in that, In the second position (14), the third position (15) and the fourth position (16), each position is photographed twice.

12. The method for detecting a stacked electrode assembly according to any one of claims 3 to 11, characterized in that, when Then, the least squares method is used to obtain the misalignment of each positive pole angle relative to the corresponding negative pole angle.

13. A detection device, wherein the detection device uses the detection method of the stacked electrode assembly according to any one of claims 1 to 12 to detect the misalignment of each of the positive electrode angles relative to the corresponding negative electrode angle, characterized in that, The detection device includes: X-ray device (2), which is used to emit test light; Detector (3), which is used to detect the test light.

14. The detection device according to claim 13, characterized in that, The detection device further includes an adjustment device for adjusting the position and angle of the ray generator (2) and the detector (3) relative to the electrode assembly (1).

Images