Battery cell image acquisition method and device, electronic equipment, storage medium and program product

Abstract

This application provides a method, apparatus, electronic device, storage medium, and program product for acquiring images of battery cells. The method includes: determining a preliminary placement method based on acquired battery cell parameters and region parameters; optimizing the tilt angle based on the limiting distance from the X-ray source to the battery cell and the penetration rate under the preliminary placement method to obtain the target placement pose; determining the target limiting distance from the X-ray source to the battery cell based on the target placement pose and the battery cell size; determining a rotation angle based on the target limiting distance and the radial dimension of the X-ray tube; the rotation angle being within a preset angle range; the target limiting distance being less than the limiting distance from the X-ray source to the battery cell corresponding to one revolution of the battery cell; and scanning the area to be detected based on the rotation angle to obtain a battery cell image. This application, by determining the placement pose of the battery cell and ensuring its rotation angle is within a preset angle range, makes the target limiting distance smaller than the limiting distance corresponding to traditional detection equipment, thereby achieving higher image accuracy.

Description

Technical Field

[0001] This application relates to the field of defect detection technology, and more specifically, to a method, apparatus, electronic device, storage medium, and program product for acquiring images of battery cells. Background Technology

[0002] With the rapid development of new energy vehicles, the demand for power batteries has increased dramatically, and the safety of power batteries has received increasing attention. During battery manufacturing, various internal defects are inevitably generated. These defects not only affect battery performance and lifespan but also pose potential threats to battery reliability and safety. Therefore, defect detection is a crucial step in battery production. Strict quality control allows for the timely removal of substandard batteries, thereby ensuring product quality and safety.

[0003] Currently, computed tomography (CT) scans can be used to perform a 360° circular scan of a battery cell placed on a platform. The intensity of the X-rays received by the flat panel detector is used to construct a three-dimensional image of the battery cell, allowing for defect detection. However, the three-dimensional images acquired by CT scans suffer from low accuracy. Summary of the Invention

[0004] The purpose of this application is to provide a method, apparatus, electronic device, storage medium, and program product for acquiring battery cell images, so as to improve the imaging accuracy of detection equipment.

[0005] In a first aspect, embodiments of this application provide a method for acquiring images of a battery cell, including:

[0006] Acquire cell parameters and region parameters of the area to be detected; whereby cell parameters include cell size and internal structure information; region parameters include location information and region size.

[0007] The initial placement method is determined based on the cell parameters and area parameters; the initial placement method includes the placement posture and tilt angle.

[0008] The tilt angle is optimized based on the minimum distance between the X-ray source and the battery cell (SOD) and the penetration rate under the initial placement method to obtain the target placement pose; the minimum SOD refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the battery cell;

[0009] The target limit distance (SOD) from the X-ray source to the cell is determined based on the target placement posture and cell size. The rotation angle is determined based on the target limit SOD and the radial dimension of the X-ray tube. The rotation angle is taken within a preset angle range. The target limit SOD is less than the limit SOD corresponding to one revolution of the cell.

[0010] The area to be detected is scanned based on the rotation angle to obtain the cell image.

[0011] In this embodiment, the placement of the battery cell is determined by the battery cell parameters and the region parameters, and its rotation angle is less than one revolution. This makes the target limit SOD smaller than the limit SOD acquired by traditional CT equipment. The smaller the limit SOD, the greater the magnification and the higher the resolution, thereby obtaining higher image accuracy.

[0012] In one possible implementation of the first aspect, the initial placement method is determined based on cell parameters and area parameters, including:

[0013] The group margin of the area to be tested is determined based on the internal structure information of the battery cell; the group margin is used to characterize the size of the voids surrounding the area to be tested.

[0014] The initial placement method is determined based on location information, group margin, and whether the detection rays need to avoid the copper tabs.

[0015] The embodiments of this application determine the initial placement method based on the location information of the area to be detected, the group margin, and whether the probe rays need to avoid the copper tabs. By using the correct initial placement posture, the efficiency of subsequent fine-tuning operations is higher, and cell images that meet the accuracy requirements can be obtained.

[0016] In one possible implementation of the first aspect, the initial placement method is determined based on the cell parameters and the parameters of the defects to be detected, including:

[0017] The first limit SOD of the battery cell in a horizontal orientation and the second limit SOD of the battery cell in a vertical orientation are calculated based on the cell size and position information. The horizontal orientation refers to the plane of the battery cell tab being perpendicular to the axis of rotation of the stage; the vertical orientation refers to the plane of the battery cell tab being parallel to the axis of rotation of the stage.

[0018] The placement posture corresponding to the smaller of the first limit SOD and the second limit SOD is taken as the initial placement posture.

[0019] The penetration rate of the detection rays is calculated based on the internal structure information of the battery cell and the initial placement posture, and the tilt angle is determined based on the penetration rate of the rays.

[0020] In this application embodiment, ray penetration rate is introduced as a second optimization objective based on the limiting SOD. By calculating the effective penetration thickness and material along the path of the image under the initial posture, the potential risks to image quality are quantitatively assessed. By adjusting the tilt angle, a significant reduction in penetration thickness is achieved at the cost of a slight increase in SOD, thereby improving the signal-to-noise ratio.

[0021] In one possible implementation of the first aspect, the tilt angle is optimized based on the limiting SOD and penetration rate under the initial placement method, including:

[0022] Based on cell size, internal battery structure information, and tilt angle, a first functional relationship for limiting SOD and a second functional relationship for penetration rate are constructed respectively.

[0023] Within the range of tilt angle values, the limiting SOD corresponding to different tilt angles is calculated using the first functional relationship, and the penetration rate at the corresponding tilt angle is calculated using the second functional relationship.

[0024] When the limit SOD meets the preset SOD threshold, the tilt angle with the highest penetration rate is selected as the optimal tilt angle.

[0025] The embodiments of this application evaluate each tilt angle through functional relationships and finally select the tilt angle with the highest penetration rate. Therefore, under the premise of meeting the accuracy requirements, a cell image with a high signal-to-noise ratio is obtained.

[0026] In one possible implementation of the first aspect, the preset SOD threshold is determined by the following method:

[0027] The lower limit of the preset SOD threshold is determined based on the region size;

[0028] The upper limit of the preset SOD threshold is determined based on the preset detection accuracy.

[0029] In this embodiment, the lower limit of the SOD threshold is determined by the size of the area to be detected, and the upper limit of the SOD threshold is determined by the detection accuracy. The dual constraint conditions can meet the requirements of field coverage and detection accuracy.

[0030] In one possible implementation of the first aspect, determining the target limit SOD of the battery cell based on the target placement pose and cell size includes:

[0031] Calculate the minimum distance that the side of the battery cell closest to the X-ray source will not collide with the X-ray tube during rotation, based on the target's placement posture and the battery cell size.

[0032] The sum of the minimum distance and the preset safe distance is determined as the target limit SOD.

[0033] In this embodiment, the target limit SOD is determined by the sum of the minimum distance at which the side of the battery cell closest to the X-ray source does not collide with the X-ray tube during rotation and the preset safety distance. This minimizes the target limit SOD, thereby improving detection accuracy and reducing the risk of the battery cell colliding with the X-ray tube during rotation.

[0034] In one possible implementation of the first aspect, the rotation angle is determined based on the target limit SOD and the radial dimension of the ray tube, including:

[0035] The limiting angle of the battery cell is determined based on the maximum distance from the target X-ray source to the battery cell, the battery cell thickness, and the radial dimension; the limiting angle is used to characterize the angle at which the battery cell cannot rotate during rotation.

[0036] The rotation angle is determined based on the limiting angle.

[0037] The rotation angle can be calculated using the above formula in the embodiments of this application. By collecting projections from more angles, the accuracy of calculating the attenuation coefficient of each point inside the battery cell can be improved, thereby improving the detection accuracy.

[0038] In one possible implementation of the first aspect, the method further includes, before probing the region to be detected based on the rotation angle:

[0039] The tube voltage and tube current of the X-ray tube are determined based on the internal structure information of the battery cell and the target placement posture, and the emission power is determined based on the tube voltage and tube current.

[0040] The exposure time of the flat panel detector is determined based on the tube current;

[0041] The number of acquisition frames is determined based on the preset detection image size;

[0042] Configure the parameters of the detection equipment according to the transmission power, exposure time, and number of acquisition frames.

[0043] This application embodiment determines the detection parameters of the detection device based on the internal structure information of the battery cell and the target placement posture, so that the battery cell image obtained under the detection parameters can meet the detection accuracy requirements.

[0044] In one possible implementation of the first aspect, the rotation angle is in the range of 180° or greater and less than 360°.

[0045] In one possible implementation of the first aspect, the rotation angle is in the range of 180° or greater and 240° or less.

[0046] In this embodiment, by setting the rotatable range of the rotation angle to be greater than 180° and less than 240°, the requirements for the collected data points can be met while compressing the limit SOD.

[0047] In one possible implementation of the first aspect, the area to be detected is the welding area between the electrode tab and the adapter piece; the initial placement method is determined based on location information, group margin, and whether the probe rays need to avoid the copper electrode tab, including:

[0048] Since the group margin corresponding to the welding area between the electrode and the adapter is greater than the preset value, and the welding area between the electrode and the adapter needs to avoid the copper electrode, the initial placement method is determined to be horizontal placement.

[0049] In this embodiment, the initial placement method for the welding area between the electrode tab and the adapter piece is determined to be horizontal placement. Under horizontal placement, better detection accuracy and imaging quality can be obtained.

[0050] In one possible implementation of the first aspect, the area to be detected is the welding area between the tab and the pole; the initial placement method is determined based on location information, group margin, and whether the probe rays need to avoid the copper tab, including:

[0051] Since the group margin corresponding to the welding area between the tab and the pole is less than the preset value, and the welding area between the tab and the pole needs to avoid the copper tab, the initial placement method is determined to be vertical placement with a preset tilt angle.

[0052] In this embodiment, the initial placement method is determined to be vertical placement based on the specific situation of the welding area between the tab and the post. Under vertical placement, better detection accuracy and imaging quality can be obtained.

[0053] In one possible implementation of the first aspect, the area to be detected is the electrode tab; the initial placement method is determined based on location information, group margin, and whether the probe rays need to avoid the copper electrode tab, including:

[0054] Based on the fact that the group margin corresponding to the electrode is greater than the preset value, and the detection rays do not need to avoid the copper electrode, the initial placement method is determined to be horizontal placement.

[0055] In this embodiment, the initial placement method is determined to be horizontal placement based on the specific situation of the electrode area. Under horizontal placement, better detection accuracy and imaging quality can be obtained.

[0056] Secondly, embodiments of this application provide a battery cell image acquisition device, comprising:

[0057] The parameter acquisition module is used to acquire cell parameters and region parameters of the area to be detected; the cell parameters include cell size and internal structure information; the region parameters include location information and region size.

[0058] The initial placement method determination module is used to determine the initial placement method based on cell parameters and area parameters; the initial placement method includes placement posture and tilt angle.

[0059] The tilt angle optimization module is used to optimize the tilt angle based on the limiting SOD and penetration rate under the initial placement method to obtain the target placement pose; the limiting SOD refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the battery cell;

[0060] The limit SOD determination module is used to determine the target limit SOD of the battery cell based on the target placement pose and the cell size, and to determine the rotation angle based on the target limit SOD and the radial dimension of the X-ray tube; the rotation angle is taken within a preset angle range; the target limit SOD is less than the limit SOD corresponding to one revolution of the battery cell;

[0061] The detection module is used to scan the area to be detected based on the rotation angle to obtain the cell image.

[0062] Thirdly, embodiments of this application provide an electronic device, including: a processor, a memory, and a bus, wherein:

[0063] The processor and memory communicate with each other via a bus;

[0064] The memory stores program instructions that can be executed by the processor, and the processor can execute the method of the first aspect by calling the program instructions.

[0065] Fourthly, embodiments of this application provide a non-transitory computer-readable storage medium, comprising:

[0066] A non-transitory computer-readable storage medium stores computer instructions that cause the computer to perform the methods in the various possible implementations of the first aspect.

[0067] Fifthly, embodiments of this application provide a computer program product, including computer program instructions, which, when read and executed by a processor, perform the methods in various possible implementations of the first aspect.

[0068] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0069] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0070] Figure 1 This is a schematic flowchart of a battery cell image acquisition method provided in an embodiment of this application;

[0071] Figure 2 A schematic diagram of a horizontally arranged battery cell provided for an embodiment of the application;

[0072] Figure 3 A schematic diagram of a vertically arranged battery cell provided for an embodiment of the application;

[0073] Figure 4 A schematic diagram of a tilted battery cell arrangement provided in the application embodiment;

[0074] Figure 5 This is a schematic diagram illustrating the testing methods for comparison.

[0075] Figure 6 This is a schematic diagram of the detection process provided in an embodiment of this application;

[0076] Figure 7 A front view of the battery cell provided in an embodiment of this application;

[0077] Figure 8 A side view of the battery cell provided for an embodiment of this application;

[0078] Figure 9 A top view of the battery cell provided in an embodiment of this application;

[0079] Figure 10 This is a schematic diagram of a battery cell placed at an angle.

[0080] Figure 11 This is a schematic diagram of another type of tilted battery cell.

[0081] Figure 12 A schematic diagram of a battery cell and a ray tube provided for an embodiment of this application;

[0082] Figure 13 This is a schematic diagram of a battery cell image acquisition device provided in an embodiment of this application;

[0083] Figure 14 This is a schematic diagram of the physical structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0084] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0085] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0086] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0087] In this document, the term "embodiment" means that a particular 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 separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0088] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0089] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0090] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0091] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0092] With the rapid development of new energy vehicles, the demand for power batteries has increased dramatically, and the safety of power batteries has received increasing attention. During battery manufacturing, various internal defects are inevitably generated. These defects not only affect battery performance and lifespan but also pose potential threats to battery reliability and safety. Therefore, defect detection is a crucial step in battery production. Strict quality control allows for the timely removal of substandard batteries, thereby ensuring product quality and safety.

[0093] Among internal battery defects, tab defects are a significant cause of battery failure. As a crucial component of the battery, the tabs connect the positive and negative terminals to the external circuitry, and their condition directly impacts battery performance and safety. Common tab defects include misalignment, folding, cracking, redundancy, underpinning, and poor soldering. These defects can lead to performance degradation, such as capacity decay and increased internal resistance, while also significantly increasing safety risks, such as internal short circuits or thermal runaway, and even serious accidents like battery fires or explosions. Therefore, the detection and control of tab defects is an indispensable and critical step in the manufacturing process of power batteries.

[0094] Currently, methods for detecting electrode defects (including misalignment and folding) in bare battery cells include manual visual inspection and automated inspection technology using charge-coupled devices (CCDs). These methods can effectively remove samples with electrode defects before casing. However, issues such as ultrasonic welding defects, laser solder edge cracking, and back cracking (mostly aluminum electrodes), redundancy, and under-insertion problems in finished battery cells are mostly addressed through manual disassembly or random sampling using conventional CT (Computed Tomography) scans. Manual disassembly has low inspection efficiency, while conventional CT scans can improve efficiency, but the accuracy of the acquired images is low.

[0095] To address the aforementioned technical problems, this application provides a method for acquiring images of a battery cell. The method determines the cell's placement orientation by using cell parameters and region parameters of the area to be detected. By compressing the cell's rotation angle to less than 360° under this orientation, the target limit SOD of the cell can be made smaller than the target limit SOD of images acquired by conventional CT equipment. Because the target limit SOD is reduced, the accuracy of the images acquired by the CT equipment can be improved.

[0096] It should be noted that the battery cell image acquisition method provided in this application embodiment involves scanning a certain area on the battery cell using a CT scanner to obtain an image of the battery cell. The CT scanner in this application embodiment differs from a conventional CT scanner in that a conventional CT scanner performs a 360° circular scan, while the rotation angle of the CT scanner in this application embodiment can be determined based on the battery cell parameters and placement posture. Then, the stage on which the battery cell is placed is rotated according to the rotation angle, and the image of the battery cell is obtained through detection using the CT scanner.

[0097] The battery cell image acquisition method provided in this application embodiment can be executed by a controller. This controller is communicatively connected to a CT scanner and can send control commands (e.g., rotation angle, tilt angle, detection parameters, etc.) to the CT scanner. The CT scanner acquires images of the battery cell based on these control commands. By transforming the expert experience of engineers into standardized logic, this standardized logic can guide a series of actions such as the initial placement of the battery cell, optimization of the tilt angle, and determination of the rotation angle, thereby achieving high-quality battery cell images.

[0098] The battery cell in this application embodiment can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square-shell battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0099] Before introducing the cell image acquisition method provided in the embodiments of this application, the CT device in the embodiments of this application will be introduced.

[0100] The CT equipment can be a single-source, single-detector, dual-column system, comprising a 225kV microfocus X-ray source, a rotating stage, and a 1717 model flat panel detector. This invention develops a limited-angle function based on conventional standard CT equipment. By modifying the commands controlling the servo motor in the stage, precise control of the rotation angle is achieved, ultimately obtaining projected images at different angles on the flat panel detector. Stereoscopic data is then reconstructed using reconstruction software. It is understood that the CT equipment can also be a single-source, single-column rotating tray system, a single-source, multi-detector system, etc. The model and parameters of the aforementioned microfocus X-ray source and flat panel detector can be adjusted according to actual needs; this application does not specifically limit these aspects.

[0101] A microfocus X-ray source is a component capable of generating high-energy X-rays. Its key characteristic is a small focal spot size, ranging from 7 to 75 μm (the focal spot size is related to the power of the X-ray tube). In high-precision detection, microfocus X-ray sources facilitate high-resolution detection.

[0102] A rotating stage is a device used to support and fix the position of battery cells. Its position (x, y, and z directions) and rotation angle (0-360°) can be precisely controlled by a motor. In high-precision inspection, the placement of battery cells can be adjusted according to the location of target defects. With the center of the stage as the origin of the coordinate axis, the direction from the center of the stage to the micro-focus X-ray source on the stage plane is the x-direction; the direction perpendicular to the x-direction on the stage plane is the y-direction; and the central axial direction of the stage is the z-direction.

[0103] A flat panel detector is an imaging device responsible for capturing changes in X-ray intensity and converting them into digital signals.

[0104] Figure 1 This is a schematic flowchart of a battery cell image acquisition method provided in an embodiment of this application, as shown below. Figure 1 As shown, the method includes:

[0105] Step 101: Obtain cell parameters and area parameters of the region to be tested;

[0106] Step 102: Determine the initial placement method based on cell parameters and area parameters;

[0107] Step 103: Optimize the tilt angle based on the limit SOD and penetration rate under the initial placement method to obtain the target placement pose;

[0108] Step 104: Determine the target limit SOD of the battery cell based on the target placement pose and the battery cell size, and determine the rotation angle range based on the target limit SOD and the radial dimension of the X-ray tube;

[0109] Step 105: Scan the area to be detected based on the rotation angle to obtain the cell image.

[0110] In the specific implementation process, cell parameters include cell size and internal structural information. Taking a rectangular cell as an example, the cell size includes its length, width, and height. Internal structural information refers to the geometric structure, spatial relationships, and material properties of the various components within the cell. This mainly includes the relative positional relationship between the bare cell and the top cover, as well as the location distribution of key components such as copper tabs, aluminum tabs, adapter plates, and terminals. These cell parameters can be obtained from the 3D digital model of the cell design.

[0111] The area to be inspected refers to a specific region on or inside the battery cell, such as the tab, the welding area between the tab and the adapter plate, etc. This area is predetermined and requires quality inspection after cell production, especially targeting areas prone to defects. Workers can prepare a defect inspection list beforehand, storing all areas of the battery cell that need to be inspected. Furthermore, if other defect detection methods indicate a potential defect in a certain area of ​​the cell, an image of that area can be obtained for further verification and to determine the defect's morphology.

[0112] The region parameters of the area to be inspected include location information and region size. Location information refers to the specific position of the area to be inspected on the battery cell, such as the laser welding surface between the top cover electrode and the adapter plate. During image acquisition, the position of the battery cell on the rotating stage is specifically the position of the area to be inspected on the battery cell on the central axis of the rotating stage. Therefore, location information is one of the reference factors for battery cell placement.

[0113] Region size refers to the area of ​​the region to be detected. When acquiring images, the entire region to be detected needs to be presented in the acquired cell image. Therefore, region size is one of the reference factors for adjusting the acquisition field of view.

[0114] Therefore, the cell parameters and the area parameters of the area to be tested can be entered or selected by the staff.

[0115] After obtaining the cell parameters and area parameters, the initial placement method of the cell on the platform can be determined. This initial placement method includes the placement posture and tilt angle. The placement posture can include horizontal or vertical placement. The tilt angle characterizes the tilt angle of the cell after horizontal or vertical placement. This tilt angle refers to the angle between the surface of the cell, which was originally in contact with the platform, and the plane of the platform after tilting. It should be noted that when tilting the cell, a matching clamp with an adjustable angle or a clamp with mechanically controlled leveling can be used to assemble and secure the cell with the platform.

[0116] Figure 2 This is a schematic diagram of a battery cell placed horizontally, as provided in the embodiment of the application, where the tilt angle is 0. Figure 3 This is a schematic diagram of a battery cell vertically arranged as provided in the embodiment of the application, where the tilt angle is 0. Figure 4 The illustration provided in the application provides a schematic diagram of a battery cell tilted at a certain angle, which is based on a horizontal placement.

[0117] After determining the initial placement, the limiting SOD and transmittance of the battery cell can be determined. SOD (Source-to-Object Distance) refers to the distance from the focal point of the X-ray tube to the center of rotation of the stage. Limiting SOD refers to the minimum SOD value achievable within the capabilities of the CT equipment and the requirements of the scan. In other words, it means bringing the object being tested (the battery) as close to the X-ray source as possible, until it is "no closer." This critical point of "no closer" is the limiting SOD.

[0118] Penetration rate refers to the ratio of the residual intensity of X-rays after they have penetrated the cell to their initial intensity. Factors affecting penetration rate include the material density and atomic number of the cell through which X-rays pass, the path length, and the X-ray energy. Therefore, given a fixed X-ray energy, to improve penetration rate, the tilt angle of the cell can be adjusted to prevent X-rays from passing through areas of high material density, or the thickness through which the X-rays penetrate can be reduced. However, adjusting the tilt angle may increase the thickness of the cell through which the X-rays need to penetrate, even if it prevents X-rays from passing through areas of high material density. Furthermore, tilting the cell will change the limiting SOD (Surface Area Displacement), for example, increasing it, which can affect detection accuracy. Therefore, a balance needs to be struck between the limiting SOD and penetration rate to ultimately determine the optimal tilt angle.

[0119] After determining the optimal tilt angle, the target placement pose can be obtained. Based on the target placement pose, the target limit SOD can be calculated.

[0120] The radial dimension of the X-ray tube is known. After obtaining the target limit SOD, the rotation angle that the stage can rotate can be calculated based on the radial dimension of the X-ray tube and the target limit SOD. This rotation angle takes a value within a preset angle range, which refers to the interval formed by the minimum and maximum rotation angles of the stage during image acquisition. The upper limit of this preset angle range is less than the traditional maximum rotation angle of the stage. The value of this range can be [180°, 360°]. Setting the rotation to at least 180° is because it is only possible to determine the position of a point on a certain ray, but not its specific position on that line. This is equivalent to establishing an equation with infinitely many solutions. Rotating it by 180° is equivalent to establishing multiple equations from multiple directions (covering a range exceeding 180°). When the projection angle covers more than 180°, the intersection of all these rays is the uniquely determined position. If the rotation angle is less than 180°, these rays cannot intersect at a unique point, leading to blurred and non-unique reconstructions, resulting in artifacts. During image acquisition, the specific value of the stage's rotation angle is within this rotation angle range. Furthermore, since the battery cell itself has a certain thickness, the range of the rotation angle can be [180°, 240°].

[0121] This application sets the rotation angle to less than 360°. Compared to rotating 360°, the target limit SOD will be reduced. See details for further information. Figure 5 and Figure 6 , Figure 5 This is a schematic diagram illustrating the testing methods for comparison. Figure 6 This is a schematic diagram of the detection provided in an embodiment of this application. Figure 5 and Figure 6 As can be seen, when rotating 360°, the limit SOD value is determined based on the farthest distance between a point on the surface of the battery cell and the center of rotation. In the embodiments of this application, under the same target placement posture, the target limit SOD when rotating less than 360° is smaller than... Figure 5 The target limit of SOD.

[0122] After determining the rotation angle, the control stage rotates the area to be inspected according to the rotation angle, the X-ray tube emits X-rays to the area to be inspected, the flat panel detector receives the X-rays, and generates an image of the battery cell based on the received X-rays.

[0123] The placement and orientation of the battery cell are determined by the cell parameters and region parameters, and its rotation angle is less than 360°. This makes the target limit SOD smaller than the limit SOD acquired by traditional CT equipment. The smaller the limit SOD, the greater the magnification and the higher the resolution, thus obtaining higher image accuracy.

[0124] In this embodiment, the placement of the battery cell is determined by the battery cell parameters and the region parameters, and its rotation angle is less than 360°. This makes the target limit SOD smaller than the limit SOD acquired by traditional CT equipment. The smaller the limit SOD, the greater the magnification and the higher the resolution, thereby obtaining higher image accuracy.

[0125] Based on the above embodiments, a preliminary placement method is determined according to cell parameters and area parameters, including:

[0126] Determine the group margin of the area to be tested based on the internal structure information of the battery cell;

[0127] The initial placement method is determined based on location information, group margin, and whether the detection rays need to avoid the copper tabs.

[0128] In practical implementation, group margin is used to characterize the size of the gap around the area to be inspected. During the design of the battery cell, there is an overall group margin value for the cell. Local data can be calculated through simulation based on the cell's design parameters, or by using a CT pre-scan to obtain the distance between the casing and the boundary of the target area. This gap provides a channel for X-rays. If the defect location happens to be near this gap, the X-rays can penetrate directly without first penetrating the thick, highly attenuating bare battery cell, thus achieving better imaging results. Since the X-ray tube emits X-rays directly towards the central axis, during image acquisition, the area to be inspected within the battery cell is often placed on the central axis of the stage, and can be positioned in various ways, such as horizontal, vertical, or tilted. A horizontal placement means that the plane of the battery cell's tabs is perpendicular to the axis of rotation of the stage. Figure 2 As shown; the so-called vertical placement posture means that the plane where the battery cell's tabs are located is parallel to the axis of rotation of the platform, such as... Figure 3 As shown.

[0129] When determining the initial placement method based on location information, group margin, and whether it is necessary to avoid copper tabs, the specific method can be as follows:

[0130] If the target area is located inside the cell (such as the middle section of the tab), the initial choice for cell placement is vertical placement. The reason is that internal defects cannot utilize the group margin at the top. Although vertical placement results in greater penetration thickness, it is the only feasible solution. Subsequent compensation will be achieved by increasing the radiation energy.

[0131] If the target area is located on top of the cell, determine whether its group margin is sufficient (i.e., whether there is enough gap for the ray to pass through directly). If the group margin is sufficient, proceed to the next step; if the group margin is insufficient, choose to place it vertically.

[0132] If the group margin is sufficient, determine whether copper components need to be avoided in the ray path. If avoiding copper tabs is not necessary (e.g., the target area itself is an aluminum component with no surrounding copper), then the initial choice is horizontal placement. This is because horizontal placement maximizes the use of group margin, minimizes the ray penetration path, achieves the highest image signal-to-noise ratio, and typically obtains the minimum SOD (source-to-object distance), thus achieving the highest spatial resolution. If avoiding copper tabs is necessary (e.g., copper poles or tabs are located right next to the target area), then the initial choice is tilted placement.

[0133] In addition, a table or decision tree can be pre-built to establish the correspondence between the location information of the cell to be tested area, group margin, whether the detection rays need to avoid the copper tabs, and the initial placement method. In practical applications, the initial placement method is determined through this correspondence table or decision tree.

[0134] It should be noted that the high atomic number of copper will cause strong attenuation of X-rays and severe ray hardening artifacts, which will affect image quality.

[0135] The embodiments of this application determine the initial placement method based on the location information of the area to be detected, the group margin, and whether the probe rays need to avoid the copper tabs. By using the correct initial placement posture, the efficiency of subsequent fine-tuning operations is higher, and cell images that meet the accuracy requirements can be obtained.

[0136] Based on the above embodiments, this application also provides a method for determining a preliminary placement method, as follows:

[0137] The first limit SOD of the battery cell in a horizontal orientation and the second limit SOD of the battery cell in a vertical orientation are calculated based on the cell size and position information. The horizontal orientation refers to the plane of the battery cell tab being perpendicular to the axis of rotation of the stage; the vertical orientation refers to the plane of the battery cell tab being parallel to the axis of rotation of the stage.

[0138] The placement posture corresponding to the smaller of the first limit SOD and the second limit SOD is taken as the initial placement posture.

[0139] The X-ray transmittance is calculated based on the internal structure information of the battery cell and the initial placement posture, and the tilt angle is determined based on the X-ray transmittance.

[0140] In the specific implementation process, when determining the initial placement method, we can first determine the placement posture of the battery cells, that is, whether they need to be placed horizontally or vertically, and then determine whether it is necessary to tilt the horizontally or vertically placed battery cells at a certain angle.

[0141] When determining the placement orientation of the battery cell, the first limiting SOD (Surface Area Defect) in a horizontal placement orientation and the second limiting SOD in a vertical placement orientation can be calculated. If the first limiting SOD is less than the second limiting SOD, then a horizontal placement orientation is selected.

[0142] After determining the horizontal placement orientation, the penetration rate of the detection rays in the horizontal orientation of the battery cell is simulated and calculated based on the internal structure information of the battery cell. If the penetration rate does not meet the requirements, for example, if it is lower than the preset penetration rate, it is determined that the battery cell needs to be tilted at a certain angle; if the penetration rate is greater than or equal to the preset penetration rate, it is determined that the battery cell can be placed horizontally. It should be noted that if the penetration rate does not meet the requirements, the tilt angle can be set to the default value, such as 30°, and then subsequent tilt angle optimization can be performed.

[0143] In this application embodiment, ray penetration rate is introduced as a second optimization objective based on the limiting SOD. By calculating the effective penetration thickness and material along the path of the image under the initial posture, the potential risks to image quality are quantitatively assessed. By adjusting the tilt angle, a significant reduction in penetration thickness is achieved at the cost of a slight increase in SOD, thereby improving the signal-to-noise ratio.

[0144] Based on the above embodiments, the tilt angle is optimized according to the limiting SOD and penetration rate under the initial placement method, including:

[0145] A functional relationship between the limiting SOD and the penetration rate is constructed based on the cell size, internal battery structure information, and tilt angle.

[0146] Within the range of tilt angle values, the limiting SOD and transmittance corresponding to different tilt angles are calculated through functional relationships;

[0147] When the limit SOD meets the preset SOD threshold, the tilt angle with the highest penetration rate is selected as the optimal tilt angle.

[0148] In practical implementation, the tilt angle is a key parameter for balancing detection accuracy and imaging quality. The main purpose of this application's embodiments is to use the tilt angle as an optimization variable, and through the establishment of a mathematical model, automatically find the optimal solution that achieves the best imaging quality (maximum penetration) while satisfying detection accuracy.

[0149] Constructing the first functional relationship:

[0150] Assume that when the battery cell is not tilted (θ=0°), its center coincides with the rotation center of the stage. When the battery cell is tilted by an angle θ around the rotation center, the position of its outer contour in space changes. The distance from every point on the surface of the battery cell to the X-ray source changes. Calculate the distances from all points on the battery cell casing to the X-ray source, and the minimum value (plus a safety margin to prevent collisions) is the allowable limit SOD at that angle θ.

[0151] The first functional relationship can be expressed using geometry and trigonometric functions. For example, when a horizontally placed battery cell is tilted, its limiting SOD may be determined by the new nearest point: SOD(θ)=f(a,b,c,θ)≈K-(H / 2)*sin(θ).

[0152] Where K is the limiting SOD at θ=0°, and H is the cell height. It should be noted that the above method for calculating the limiting SOD is a simplified linear example; the actual function may be more complex, but both can be derived from geometric relationships.

[0153] Constructing the second functional relationship:

[0154] For a given θ, simulate the path of a primary X-ray beam emitted from the source, passing through the cell, and reaching the detector. Decompose this path into different material segments it traverses. For example, the path might pass through: the outer shell (length...) ), airspace / group margin ( ), aluminum tabs ( ), electrolyte ( The total attenuation along the entire path is the sum of the attenuations of each segment. Therefore, the transmittance function is: .

[0155] in, It is the linear attenuation coefficient of the i-th material (determined by material properties and ray energy). It is the length of the ray passing through the material, and it is a function of θ.

[0156] The tilt angle can be preset within a range, for example, [-30°, 30°], with the sign of the angle indicating the direction of tilt. The tilt angle adjustment step can be 1°; a smaller step size results in more accurate calculations but also takes longer. Each time the tilt angle is adjusted, the limiting SOD and transmittance are calculated according to the first and second functional relationships described above, respectively.

[0157] The preset SOD threshold is determined by the spatial resolution required for this detection task. Therefore, we can first filter out all tilt angles that meet the preset SOD threshold, and then select the tilt angle with the maximum penetration rate from the filtered tilt angles as the optimal tilt angle.

[0158] The embodiments of this application evaluate each tilt angle through a functional relationship and finally select the tilt angle with the highest penetration rate. Therefore, under the premise of meeting the accuracy requirements, a cell image with a high signal-to-noise ratio is obtained.

[0159] Based on the above embodiments, the preset SOD threshold is determined by the following method:

[0160] The lower limit of the preset SOD threshold is determined based on the region size;

[0161] The upper limit of the preset SOD threshold is determined based on the preset detection accuracy.

[0162] In practical implementation, SOD (Surface Area Determination) is a factor affecting the field of view and spatial resolution in CT scans. The field of view determines the area that can be covered in a single image, while spatial resolution determines the smallest resolvable defect size.

[0163] The area size refers to the maximum diameter of the circumscribed circle or the length of the diagonal of the area to be detected. The flat panel detector size refers to the width of the effective imaging area of ​​the flat panel detector. It is calculated using the formula FOV = W * (SOD / SDD). Here, FOV is the field of view, SDD is the distance from the X-ray tube's emission source to the flat panel detector (usually a fixed value for the equipment), and W is the flat panel detector size. Based on this formula, the SOD can be calculated, which is the lower limit of the preset SOD threshold.

[0164] The preset detection accuracy refers to the minimum defect size that is required to be reliably detected. According to the formula... Calculate the upper limit of the preset SOD threshold. ,in, The system's limiting resolution is determined by the focal size of the X-ray source and the pixel size of the detector, which are preset values. Geometric magnification .

[0165] In this embodiment, the lower limit of the SOD threshold is determined by the size of the area to be detected, and the upper limit of the SOD threshold is determined by the detection accuracy. The dual constraint conditions can meet the requirements of field coverage and detection accuracy.

[0166] Based on the above embodiments, the target limit SOD of the battery cell is determined based on the target placement pose and cell size, including:

[0167] Calculate the minimum distance that the side of the battery cell closest to the X-ray source will not collide with the X-ray tube during rotation, based on the target's placement posture and the battery cell size.

[0168] The sum of the minimum distance and the preset safe distance is determined as the target limit SOD.

[0169] In the specific implementation process, after the target placement posture of the battery cell is determined, the minimum distance that the side of the battery cell closest to the X-ray source will not collide with the X-ray tube during rotation can be calculated.

[0170] Figure 7 This is a front view of the battery cell provided in an embodiment of this application. Figure 8 This is a side view of the battery cell provided in an embodiment of this application. Figure 9 This is a top view of a battery cell provided in an embodiment of this application. Assume the cell's length is *a*, height is *b*, and width is *c*. If the target detection area (defect 1) is on the top cover of the finished battery cell, such as... Figure 9 As shown. The area to be measured is around the aluminum electrode post, at a distance from the edge of the long side of the top cover. If the target is positioned such that the battery cells are horizontally placed, the minimum distance is... At this point, the spatial resolution of the target imaging area is relatively high, but it is easily affected by other areas on the top cover, especially the beam hardening caused by the copper poles and copper tabs. If the target is placed vertically, its minimum distance is 1 / 2c. In this case, the image signal-to-noise ratio is poor due to the radiation dose attenuation caused by the bare cell. To avoid the influence of the copper poles, copper tabs, and the thickness of the bare cell that the radiation needs to penetrate, if the target is placed at an angle (θ), its minimum distance is... To ensure that the copper electrode post and copper electrode tab are outside the imaging field of view, and to adjust the cell tilt angle to minimize the thickness of the bare cell that the X-ray needs to penetrate while ensuring the system's detection accuracy. Figure 10 This is a schematic diagram of a battery cell placed at an angle. Figure 11 This is a schematic diagram of another type of tilted battery cell. (Example) Figure 10 The placement shown has a large tilt angle θ and a small limiting SOD, but the radiation needs to penetrate a larger thickness of the bare cell, resulting in greater radiation dose loss and a slight decrease in image quality. Therefore, the tilt angle needs to be adjusted, such as... Figure 11 As shown, the adjusted battery cell has a smaller tilt angle θ (indicated by the yellow dashed line) and a larger limiting SOD. Although the thickness of the bare battery cell that the X-ray needs to penetrate is smaller and the image quality is better, the detection accuracy of the system is not as high as that shown by the red dashed line.

[0171] If the area to be tested is inside the finished battery cell, such as Figure 7 As shown, it should be noted that defect 2 is located inside the battery cell; however, to clearly indicate its location, it has been marked on the cell surface. The defect length is... The area to be tested is around the aluminum tabs, at a distance of [height] from the top cover of the cell. If the target is placed vertically, its minimum distance is At this point, the spatial resolution of the target imaging area is high, but the signal-to-noise ratio of the image is poor due to the radiation dose attenuation caused by the bare battery cell. If the target is placed at an angle, its minimum distance is... This placement method can effectively avoid the influence of other areas on the imaging quality of the target area, but it should be noted that the field of view of the target area should meet certain requirements. Only then can complete imaging of defect 2 be achieved.

[0172] After obtaining the minimum distance of the battery cell in the target placement position, in order to improve the safety of the battery cell during rotation, that is, to prevent it from colliding with the X-ray tube, a safety margin, namely a preset safety distance, can be set. The sum of the minimum distance and the preset safety distance is taken as the target limit SOD.

[0173] It should be noted that the reason why the minimum distance that the side of the battery cell closest to the X-ray source does not collide with the X-ray tube during the rotation process is calculated in this application embodiment is because the rotation angle of the battery cell is less than 360°, and the edge of the battery cell on the side away from the X-ray source will not pass through the X-ray tube.

[0174] In this embodiment, the target limit SOD is determined by the sum of the minimum distance at which the side of the battery cell closest to the X-ray source does not collide with the X-ray tube during rotation and the preset safety distance. This minimizes the target limit SOD, thereby improving detection accuracy and reducing the risk of the battery cell colliding with the X-ray tube during rotation.

[0175] Based on the above embodiments, the rotation angle is determined based on the target limit SOD and the radial dimension of the ray tube, including:

[0176] The limiting angle of the battery cell is determined based on the maximum distance from the target X-ray source to the battery cell, the battery cell thickness, and the radial dimension; the limiting angle is used to characterize the angle at which the battery cell cannot rotate during rotation.

[0177] The rotation angle is determined based on the limiting angle.

[0178] In the specific implementation process Figure 12 A schematic diagram of a battery cell and X-ray tube provided for an embodiment of this application is shown below. Figure 12 As shown. For ease of drawing, the battery cell is approximated as a point (in reality, the battery cell has a certain thickness d). To avoid collision with the X-ray tube, the angle between the battery cell and the X-ray tube can be calculated. This included angle is called the non-rotational angle. The non-rotational angle refers to the angle at which the battery cell cannot rotate during rotation to prevent it from colliding with the X-ray tube. Subtracting this included angle from 360° gives the angle at which the battery cell can rotate. That is, the formula... .in, The rotation angle; Radial dimension; For the target limit of SOD, This refers to the thickness of the battery cell.

[0179] The rotation angle can be calculated using the above formula in the embodiments of this application. By collecting projections from more angles, the accuracy of calculating the attenuation coefficient of each point inside the battery cell can be improved, thereby improving the detection accuracy.

[0180] Based on the above embodiments, before probing the area to be detected based on the rotation angle, the method further includes:

[0181] The tube voltage and tube current of the X-ray tube are determined based on the internal structure information of the battery cell and the target placement posture, and the emission power is determined based on the tube voltage and tube current.

[0182] The exposure time of the flat panel detector is determined based on the tube current;

[0183] The number of acquisition frames is determined based on the preset detection image size;

[0184] Configure the parameters of the detection equipment according to the transmission power, exposure time, and number of acquisition frames.

[0185] In the specific implementation process, the tube voltage of the X-ray tube determines the highest and average energy of the X-rays. The tube voltage is determined based on the internal structure information of the cell (e.g., material composition, thickness and density of the thickest / denseest part) and the target placement posture (which determines the X-ray penetration path). The logic for determining the tube voltage is: to use the lowest possible voltage while meeting the requirements of penetration rate.

[0186] The tube current of the X-ray tube determines the number of electrons bombarding the target per unit time, i.e., the intensity of the generated X-ray photon flux. More photons result in a higher image signal-to-noise ratio and lower noise. After determining the tube voltage, the tube current is determined based on the estimated transmittance and the required image signal-to-noise ratio. The logic for determining the tube current is: after determining the tube voltage, use the lowest possible current while still meeting the required image signal-to-noise ratio.

[0187] Once the tube voltage and tube current are determined, the emission power of the ray tube can be calculated.

[0188] The exposure time and tube current together determine the total number of photons received by the detector, i.e., the exposure amount. The exposure amount directly determines the final signal-to-noise ratio (SNR) of the image. Therefore, after determining the tube current, the exposure time can be determined in conjunction with the preset image SNR. The formula for calculating the image SNR is: ,in, For image signal-to-noise ratio, For system constants, For tube current, The exposure time is the time taken to expose the tube. Therefore, the exposure time is inversely proportional to the tube current. Given that the total exposure amount is known, the exposure time can be shortened by increasing the tube current, thereby improving the detection efficiency.

[0189] To accurately reconstruct an image without artifacts, a sufficient number of projections (frames) must be acquired within the rotation range. Assuming the radius of the reconstruction region is R, and the required resolution is... Therefore, the circumferential bearing is 2πR. According to the Nyquist sampling theorem, the sampling interval should be less than or equal to... Therefore, the minimum number of sampling frames is In practical applications, the selected number of sampling frames will be greater than the minimum number of sampling frames. For example, twice the minimum number of sampling frames can be used as the number of sampling frames in this embodiment.

[0190] The parameters of the detection equipment (such as CT equipment) can be configured according to the determined transmission power, exposure time, and number of acquisition frames.

[0191] This application embodiment determines the detection parameters of the detection device based on the internal structure information of the battery cell and the target placement posture, so that the battery cell image obtained under the detection parameters can meet the detection accuracy requirements.

[0192] Based on the above embodiments, for the case where the area to be detected is the welding area between the electrode tab and the adapter piece; the initial placement method is determined based on position information, group margin, and whether the probe rays need to avoid the copper electrode tab, including:

[0193] Since the group margin corresponding to the welding area between the electrode and the adapter is greater than the preset value, and the welding area between the electrode and the adapter needs to avoid the copper electrode, the initial placement method is determined to be horizontal placement.

[0194] In the specific implementation process, due to the large group margin corresponding to the welding area between the electrode tab and the adapter piece, and the need to avoid the copper electrode tab, it can be initially determined to place it horizontally. The defect size of ultrasonic cold solder joint is 40~80 micrometers, and the required accuracy is set at 20 micrometers. The length of the test area from the edge of the shell and the cell thickness are known, and the limit SOD is obtained through the above calculations. Adjust the position of the cell stage to ensure that the spatial resolution meets the test requirements; adjust the X-ray tube power to ensure that the cell is penetrated while the X-ray focal spot size is appropriate.

[0195] In this embodiment, the initial placement method for the welding area between the electrode tab and the adapter piece is determined to be horizontal placement. Under horizontal placement, better detection accuracy and imaging quality can be obtained.

[0196] Based on the above embodiments, for areas where the area to be detected is the welding area between the electrode tab and the electrode post; based on location information, group margin, and whether the probe rays need to avoid the copper electrode tab, a preliminary placement method is determined, including:

[0197] Since the group margin corresponding to the welding area between the tab and the pole is less than the preset value, and the welding area between the tab and the pole needs to avoid the copper tab, the initial placement method is determined to be vertical placement with a preset tilt angle.

[0198] In the specific implementation process, since the cell group margin in this area is small, and the target detection area needs to avoid the influence of copper poles, copper tabs and bare cells on the imaging quality as much as possible, the sample placement method can be initially determined to be that the cells are placed at an angle.

[0199] The defect size in laser welding is 20 micrometers, and the required accuracy is set at 10 micrometers. The length of the area to be tested from the edge of the shell is known, as is the cell thickness. The tilt angle can be determined after balancing imaging quality and accuracy. The limiting SOD is obtained through the above calculations. The parameters of the optical tube, the flat plate, and the host computer are adjusted to ensure that the component accuracy matches the system accuracy.

[0200] In this embodiment, the initial placement method is determined to be vertical placement based on the specific situation of the welding area between the tab and the post. Under vertical placement, better detection accuracy and imaging quality can be obtained.

[0201] Based on the above embodiments, for the case where the area to be detected is a tab; the initial placement method is determined based on location information, group margin, and whether the detection rays need to avoid the copper tab, including:

[0202] Based on the fact that the group margin corresponding to the electrode is greater than the preset value, and the detection rays do not need to avoid the copper electrode, the initial placement method is determined to be horizontal placement.

[0203] In the specific implementation process, when the area to be tested is the tab and the defect type to be tested is tab insertion or redundancy, since the finished cell group in this area has a large margin and the target testing area does not need to avoid the copper tab, the sample placement method can be initially determined to be horizontal placement of the cells.

[0204] When the area to be inspected is the tab, and the defect type to be detected is a crack on the back of the tab, since the finished cell group has a large margin in this area and the target inspection area does not need to avoid the copper tab, the sample placement method can be initially determined to be horizontal placement of the cells. Unlike tab insertion / redundancy, the precision required for tab cracking is higher.

[0205] In this embodiment, the initial placement method is determined to be horizontal placement based on the specific situation of the electrode area. Under horizontal placement, better detection accuracy and imaging quality can be obtained.

[0206] Figure 13 This is a schematic diagram of a battery cell image acquisition device provided in an embodiment of this application. The device can be a module, program segment, or code on an electronic device. It should be understood that this device is similar to the one described above. Figure 1 The method implementation corresponds to this and can be executed. Figure 1 The specific functions of the device involved in each step of the method embodiment can be found in the description above; to avoid repetition, detailed descriptions are omitted here. The device includes: a parameter acquisition module 801, a preliminary placement method determination module 802, a tilt angle optimization module 803, a limit SOD determination module 804, and a detection module 805, wherein:

[0207] The parameter acquisition module 801 is used to acquire cell parameters and region parameters of the area to be detected; wherein, the cell parameters include cell size and internal structure information of the cell; the region parameters include location information and region size;

[0208] The preliminary placement method determination module 802 is used to determine the preliminary placement method based on cell parameters and area parameters; the preliminary placement method includes placement posture and tilt angle.

[0209] The tilt angle optimization module 803 is used to optimize the tilt angle based on the limit SOD and penetration rate under the initial placement method to obtain the target placement pose; the limit SOD refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the battery cell;

[0210] The limit SOD determination module 804 is used to determine the target limit SOD of the battery cell based on the target placement pose and the battery cell size, and to determine the rotation angle based on the target limit SOD and the radial dimension of the ray tube; the rotation angle is taken within a preset angle range; the target limit SOD is less than the limit SOD corresponding to one revolution of the battery cell;

[0211] The detection module 805 is used to scan the area to be detected based on the rotation angle to obtain the cell image.

[0212] Based on the above embodiments, the preliminary placement method determination module 802 is specifically used for:

[0213] The group margin of the region to be tested is determined based on the internal structure information of the battery cell; the group margin is used to characterize the size of the void around the region to be tested.

[0214] The initial placement method is determined based on the location information, the group margin, and whether the detection rays need to avoid the copper tabs.

[0215] Based on the above embodiments, the preliminary placement method determination module 802 is specifically used for:

[0216] The first limit SOD of the battery cell in a horizontal orientation and the second limit SOD of the battery cell in a vertical orientation are calculated based on the cell size and the position information. The horizontal orientation refers to the plane where the battery cell's tabs are located being perpendicular to the axis of rotation of the platform. The vertical orientation refers to the plane where the battery cell's tabs are located being parallel to the axis of rotation of the platform.

[0217] The placement posture corresponding to the smaller of the first limit SOD and the second limit SOD is taken as the initial placement posture.

[0218] The X-ray transmittance is calculated based on the internal structure information of the battery cell and the initial placement posture, and the tilt angle is determined based on the X-ray transmittance.

[0219] Based on the above embodiments, the tilt angle optimization module 803 is specifically used for:

[0220] Based on the cell size, the internal structure information of the battery, and the tilt angle, a first functional relationship for the limit SOD and a second functional relationship for the penetration rate are respectively constructed.

[0221] Within the range of the tilt angle, the limiting SOD corresponding to different tilt angles is calculated using the first functional relationship, and the penetration rate at the corresponding tilt angle is calculated using the second functional relationship.

[0222] When the limiting SOD meets the preset SOD threshold, the tilt angle with the highest penetration rate is selected as the optimal tilt angle.

[0223] Based on the above embodiments, the preset SOD threshold is determined by the following method:

[0224] The lower limit of the preset SOD threshold is determined based on the area size;

[0225] The upper limit of the preset SOD threshold is determined based on the preset detection accuracy.

[0226] Based on the above embodiments, the limit SOD determination module 804 is specifically used for:

[0227] Based on the target placement posture and the cell size, calculate the minimum distance that the side of the cell closest to the X-ray source will not collide with the X-ray tube during rotation;

[0228] The sum of the minimum distance and the preset safety distance is determined as the target limit SOD.

[0229] Based on the above embodiments, the limit SOD determination module 804 is specifically used for:

[0230] The limiting angle of the battery cell is determined based on the extreme distance from the target radiation source to the battery cell and the radial dimension; the limiting angle is used to characterize the angle at which the battery cell cannot rotate during rotation.

[0231] The rotation angle is determined based on the limiting angle.

[0232] Based on the above embodiments, the device further includes a parameter configuration module, used for:

[0233] The tube voltage and tube current of the X-ray tube are determined based on the internal structure information of the battery cell and the target placement posture, and the emission power is determined based on the tube voltage and the tube current.

[0234] The exposure time of the flat panel detector is determined based on the tube current;

[0235] The number of acquisition frames is determined based on the preset detection image size;

[0236] The detection device is configured with parameters based on the transmission power, the exposure time, and the number of acquisition frames.

[0237] Based on the above embodiments, the value range of the rotation angle is greater than or equal to 180° and less than 360°.

[0238] Based on the above embodiments, the value range of the rotation angle is greater than or equal to 180° and less than or equal to 240°.

[0239] Based on the above embodiments, the area to be detected is the welding area between the electrode tab and the adapter piece; the preliminary placement method determination module 802 is specifically used for:

[0240] Based on the fact that the group margin corresponding to the welding area between the electrode tab and the adapter piece is greater than a preset value, and that the welding area between the electrode tab and the adapter piece needs to avoid the copper electrode tab, the initial placement method is determined to be horizontal placement.

[0241] Based on the above embodiments, the area to be detected is the welding area between the electrode tab and the adapter piece; the preliminary placement method determination module 802 is specifically used for:

[0242] Since the group margin corresponding to the welding area between the electrode tab and the electrode post is less than a preset value, and the welding area between the electrode tab and the electrode post needs to avoid the copper electrode tab, the initial placement method is determined to be vertical placement with a preset tilt angle.

[0243] Based on the above embodiments, the area to be detected is a tab; the preliminary placement method determination module 802 is specifically used for:

[0244] Based on the fact that the group margin corresponding to the electrode tab is greater than the preset value, and the detection rays do not need to avoid the copper electrode tab, the initial placement method is determined to be horizontal placement.

[0245] Figure 14 This is a schematic diagram of the physical structure of the electronic device provided in the embodiments of this application, such as... Figure 14 As shown, the electronic device includes: a processor 901, a memory 902, and a bus 903; wherein:

[0246] The processor 901 and the memory 902 communicate with each other through the bus 903;

[0247] The processor 901 is used to call program instructions in the memory 902 to execute the methods provided in the above-described method embodiments, including, for example, acquiring cell parameters and region parameters of the area to be detected; wherein, the cell parameters include cell size and internal structure information; the region parameters include position information and region size; determining a preliminary placement method based on the cell parameters and region parameters; the preliminary placement method includes placement posture and tilt angle; optimizing the tilt angle based on the limiting SOD and penetration rate under the preliminary placement method to obtain the target placement posture; the limiting SOD refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the cell; determining the target limiting SOD of the cell based on the target placement posture and cell size, and determining the rotation angle based on the target limiting SOD and the radial dimension of the X-ray tube; the rotation angle is taken within a preset angle range; the target limiting SOD is less than the limiting SOD corresponding to one revolution of the cell; scanning the area to be detected based on the rotation angle to obtain a cell image.

[0248] The processor 901 can be an integrated circuit chip with signal processing capabilities. The processor 901 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor.

[0249] The memory 902 may include, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.

[0250] This embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, and when the program instructions are executed by the computer, the computer can execute the methods provided in the above-described method embodiments, such as: acquiring cell parameters and region parameters of the area to be detected; wherein, the cell parameters include cell size and internal structure information of the cell; the region parameters include position information and region size; determining a preliminary placement method based on the cell parameters and region parameters; the preliminary placement method includes placement posture and tilt angle; optimizing the tilt angle based on the limiting SOD and penetration rate under the preliminary placement method to obtain a target placement posture; the limiting SOD refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the cell; determining the target limiting SOD of the cell based on the target placement posture and cell size, and determining the rotation angle based on the target limiting SOD and the radial dimension of the X-ray tube; the rotation angle is taken within a preset angle range; the target limiting SOD is less than the limiting SOD corresponding to one revolution of the cell; scanning the area to be detected based on the rotation angle to obtain a cell image.

[0251] This embodiment provides a non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the methods provided in the above-described method embodiments. These instructions include, for example, acquiring cell parameters and region parameters of the area to be detected; wherein the cell parameters include cell size and internal structure information; the region parameters include location information and region size; determining a preliminary placement method based on the cell parameters and region parameters; the preliminary placement method includes placement posture and tilt angle; optimizing the tilt angle based on the limiting SOD and transmittance under the preliminary placement method to obtain a target placement posture; the limiting SOD refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the cell; determining the target limiting SOD of the cell based on the target placement posture and cell size, and determining the rotation angle based on the target limiting SOD and the radial dimension of the X-ray tube; the rotation angle is within a preset angle range; the target limiting SOD is less than the limiting SOD corresponding to one revolution of the cell; and scanning the area to be detected based on the rotation angle to obtain a cell image.

[0252] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0253] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0254] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0255] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0256] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of 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 scope of protection of this application.

Claims

1. A method for acquiring images of a battery cell, characterized in that, include: The process involves acquiring cell parameters and region parameters of the area to be detected; wherein the cell parameters include cell size and internal structure information; and the region parameters include location information and region size. The initial placement method is determined based on the cell parameters and area parameters; the initial placement method includes the placement posture and tilt angle. The tilt angle is optimized based on the extreme distance and penetration rate of the X-ray source to the battery cell under the initial placement method to obtain the target placement pose; the extreme distance from the X-ray source to the battery cell refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the battery cell; The limit distance from the target X-ray source to the battery cell is determined based on the target placement posture and the battery cell size. The rotation angle is determined based on the limit distance from the target X-ray source to the battery cell and the radial dimension of the X-ray tube. The rotation angle is taken within a preset angle range. The limit distance from the target X-ray source to the battery cell is less than the limit distance from the X-ray source to the battery cell corresponding to one revolution of the battery cell. The area to be detected is scanned based on the rotation angle to obtain a cell image.

2. The method according to claim 1, characterized in that, The process of determining the initial placement method based on cell parameters and area parameters includes: The group margin of the region to be tested is determined based on the internal structure information of the battery cell; the group margin is used to characterize the size of the void around the region to be tested. The initial placement method is determined based on the location information, the group margin, and whether the detection rays need to avoid the copper tabs.

3. The method according to claim 1, characterized in that, The process of determining the initial placement method based on cell parameters and area parameters includes: Based on the cell size and position information, the limit distance from the first radiation source to the cell in a horizontal orientation is calculated, and the limit distance from the second radiation source to the cell in a vertical orientation is also calculated. The horizontal orientation refers to the plane containing the cell's tabs being perpendicular to the axis of rotation of the stage; the vertical orientation refers to the plane containing the cell's tabs being parallel to the axis of rotation of the stage. The placement posture corresponding to the smaller of the extreme distance between the first X-ray source and the battery cell and the extreme distance between the second X-ray source and the battery cell is taken as the initial placement posture. The X-ray transmittance is calculated based on the internal structure information of the battery cell and the initial placement posture, and the tilt angle is determined based on the X-ray transmittance.

4. The method according to claim 1, characterized in that, The optimization of the tilt angle based on the limiting distance and penetration rate of the radiation source to the battery cell under the initial placement method includes: Based on the cell size, the cell internal structure information, and the tilt angle, a first functional relationship of the limiting distance from the X-ray source to the cell and a second functional relationship of the penetration rate are respectively constructed. Within the range of the tilt angle, the limit distance from the X-ray source to the battery cell corresponding to different tilt angles is calculated using the first functional relationship, and the transmittance at the corresponding tilt angle is calculated using the second functional relationship. When the maximum distance between the X-ray source and the battery cell meets the preset SOD threshold, the tilt angle with the highest penetration rate is selected as the optimal tilt angle.

5. The method according to claim 4, characterized in that, The preset SOD threshold is determined by the following method: The lower limit of the preset SOD threshold is determined based on the area size; The upper limit of the preset SOD threshold is determined based on the preset detection accuracy.

6. The method according to claim 1, characterized in that, The step of determining the limit distance from the target radiation source to the battery cell based on the target placement pose and the battery cell size includes: Based on the target placement posture and the cell size, calculate the minimum distance that the side of the cell closest to the X-ray source will not collide with the X-ray tube during rotation; The sum of the minimum distance and the preset safe distance is determined as the limit distance from the target radiation source to the battery cell.

7. The method according to claim 1, characterized in that, The determination of the rotation angle based on the limiting distance from the target X-ray source to the cell and the radial dimension of the X-ray tube includes: The limiting angle of the battery cell is determined based on the extreme distance from the target radiation source to the battery cell, the battery cell thickness, and the radial dimension; the limiting angle is used to characterize the angle at which the battery cell cannot rotate during rotation. The rotation angle is determined based on the limiting angle.

8. The method according to claim 1, characterized in that, Before scanning the region to be detected based on the rotation angle, the method further includes: The tube voltage and tube current of the X-ray tube are determined based on the internal structure information of the battery cell and the target placement posture, and the emission power is determined based on the tube voltage and the tube current. The exposure time of the flat panel detector is determined based on the tube current; The number of acquisition frames is determined based on the preset detection image size; The detection device is configured with parameters based on the transmission power, the exposure time, and the number of acquisition frames.

9. The method according to claim 1, characterized in that, The rotation angle is within the range of 180° or higher and less than 360°.

10. The method according to claim 9, characterized in that, The rotation angle is within the range of 180° and 240°.

11. The method according to claim 2, characterized in that, The area to be tested is the welding area between the electrode tab and the adapter plate; the determination of the preliminary placement method based on the position information, the group margin, and whether the probe rays need to avoid the copper electrode tab includes: Based on the fact that the group margin corresponding to the welding area between the electrode tab and the adapter piece is greater than a preset value, and that the welding area between the electrode tab and the adapter piece needs to avoid the copper electrode tab, the initial placement method is determined to be horizontal placement.

12. The method according to claim 2, characterized in that, The area to be detected is the welding area between the tab and the electrode post; the determination of the preliminary placement method based on the position information, the group margin, and whether the probe rays need to avoid the copper tab includes: Since the group margin corresponding to the welding area between the electrode tab and the electrode post is less than a preset value, and the welding area between the electrode tab and the electrode post needs to avoid the copper electrode tab, the initial placement method is determined to be vertical placement with a preset tilt angle.

13. The method according to claim 2, characterized in that, The area to be detected is the electrode tab; the determination of the preliminary placement method based on the location information, the group margin, and whether the detection rays need to avoid the copper electrode tab includes: Based on the fact that the group margin corresponding to the electrode tab is greater than the preset value, and the detection rays do not need to avoid the copper electrode tab, the initial placement method is determined to be horizontal placement.

14. A battery cell image acquisition device, characterized in that, include: The parameter acquisition module is used to: acquire cell parameters and region parameters of the area to be detected; wherein, the cell parameters include cell size and internal structure information of the cell; the region parameters include location information and region size; The initial placement method determination module is used to determine the initial placement method based on cell parameters and area parameters; the initial placement method includes placement posture and tilt angle. The tilt angle optimization module is used to optimize the tilt angle based on the limit distance and penetration rate of the X-ray source to the battery cell under the initial placement method to obtain the target placement pose; the limit distance from the X-ray source to the battery cell refers to the minimum distance between the focal point of the X-ray source tube and the rotation axis of the stage; the stage is used to support the battery cell; The module for determining the extreme distance from the X-ray source to the battery cell is used to determine the extreme distance from the target X-ray source to the battery cell based on the target placement posture and the battery cell size, and to determine the rotation angle based on the extreme distance from the target X-ray source to the battery cell and the radial dimension of the X-ray tube; the rotation angle is taken within a preset angle range; the extreme distance from the target X-ray source to the battery cell is less than the extreme distance from the X-ray source to the battery cell corresponding to one revolution of the battery cell; The detection module is used to scan the area to be detected based on the rotation angle to obtain a cell image.

15. An electronic device, characterized in that, include: Processor, memory, and bus, among which: The processor and the memory communicate with each other via the bus; The memory stores program instructions that can be executed by the processor, and the processor can execute the method as described in any one of claims 1-7 by calling the program instructions.

16. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that, when executed by a computer, cause the computer to perform the method as described in any one of claims 1-7.

17. A computer program product, characterized in that, It includes computer program instructions, which, when read and executed by a processor, perform the method as described in any one of claims 1-7.

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