Battery inspection device

Abstract

The present application provides a battery inspection device, and belongs to the technical field of batteries. The battery inspection device comprises a bearing assembly, an X-ray source, and a flat panel detector; the bearing assembly is used for bearing a battery under test; the X-ray source is used for irradiating X-rays to the battery under test on the bearing assembly; and the flat panel detector and the X-ray source are each located on one side of the bearing assembly, and the flat panel detector is used for receiving rays that are emitted by the X-ray source and penetrate through the battery under test.

Description

Battery testing device

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 202321704318.9, filed on June 30, 2023, entitled “Battery Detection Device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery detection device. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] During the battery production process, various internal defects can occur, affecting battery quality and safety. Currently, internal defect detection is typically performed manually by observing the appearance of the battery, but this detection is often unreliable, unstable, and inefficient.

[0006] Summary of the Invention

[0007] The present application aims to solve at least one of the technical problems existing in the background art. To this end, one object of the present application is to provide a battery detection device to improve the efficiency of battery defect detection.

[0008] Embodiments of the present application provide a battery testing device comprising a carrier assembly, an X-ray source, and a flat-panel detector. The carrier assembly is used to support a battery under test, and the X-ray source is used to irradiate the battery under test on the carrier assembly with X-rays. The flat-panel detector and the X-ray source are located on either side of the carrier assembly, and the flat-panel detector is used to receive X-rays emitted by the X-ray source and that penetrate the battery under test.

[0009] In the technical solution of the embodiment of the present application, the battery to be tested is placed on a carrier assembly, and the flat-panel detector and the X-ray source are respectively located on both sides of the carrier assembly. The X-ray source irradiates the battery to be tested with X-rays, and the flat-panel detector receives the X-rays emitted by the X-ray source and penetrating the battery to be tested and forms an image based on the X-rays. Since different materials have different absorption rates of X-rays, the inspection image of the battery to be tested obtained by the flat-panel detector after receiving the X-rays that pass through the battery to be tested will show various defects of the battery to be tested, thereby effectively improving the efficiency of battery defect detection and preventing the outflow of risky products.

[0010] In some embodiments, the focal spot size L1 of the X-ray source satisfies the following: L1 ≤ 80 μm. The size of the focal spot size L1 of the X-ray source is directly related to the image resolution of the battery testing device. Specifically defining the size of the focal spot size L1 of the X-ray source can better match the detection accuracy of the battery testing device with the size of the defect in the battery being tested, thereby improving detection accuracy and efficiency.

[0011] In some embodiments, the focal spot size L1 of the X-ray source satisfies: 30 μm ≤ L1 ≤ 80 μm. By limiting the focal spot size L1 of the X-ray source to: 30 μm ≤ L1 ≤ 80 μm, the service life of the X-ray source can be extended while improving detection accuracy and efficiency.

[0012] In some embodiments, the focal spot size L1 of the X-ray source satisfies: 40 μm ≤ L1 ≤ 70 μm. By limiting the focal spot size L1 of the X-ray source to: 40 μm ≤ L1 ≤ 70 μm, the detection accuracy and efficiency can be further improved, and the service life of the X-ray source can be further extended.

[0013] In some embodiments, the focal spot size L1 of the X-ray source satisfies: 50 μm ≤ L1 ≤ 60 μm. By limiting the focal spot size L1 of the X-ray source to: 50 μm ≤ L1 ≤ 60 μm, the detection accuracy and efficiency can be further improved, and the service life of the X-ray source can be further extended.

[0014] In some embodiments, the power P of the X-ray source satisfies: 65 W ≤ P ≤ 75 W. Limiting the power P of the X-ray source to 65 W ≤ P ≤ 75 W can improve the resolution of the flat panel detector to a certain extent, and can also improve the brightness of the detected image to a certain extent, thereby improving the accuracy of detection.

[0015] In some embodiments, the power P of the X-ray source satisfies: 68 W ≤ P ≤ 72 W. Further limiting the power P of the X-ray source to 68 W ≤ P ≤ 72 W can further improve the resolution of the flat panel detector, further increase the brightness of the detected image, and improve the accuracy of the detection device.

[0016] In some embodiments, the operating voltage V of the X-ray source satisfies the following conditions: V ≥ 130 kV, and / or the operating current I of the X-ray source satisfies the following conditions: I ≤ 500 μA. By limiting the operating voltage V and operating current I of the X-ray source, it is possible to provide a satisfactory X-ray dose while also ensuring the stability and reliability of the X-ray source. Furthermore, the X-ray source and the flat-panel detector can work together to meet the required accuracy requirements for testing batteries, thereby improving detection efficiency and accuracy.

[0017] In some embodiments, the operating voltage V of the X-ray source satisfies: V ≥ 150 kV, and / or the operating current I of the X-ray source satisfies: I ≤ 400 μA. By further limiting the operating voltage V or the operating current I of the X-ray source, the X-ray dose emitted by the X-ray source is further increased, while the stability and reliability of the X-ray source are further improved, thereby improving the efficiency and accuracy of detection.

[0018] In some embodiments, the flat panel detector is an amorphous silicon flat panel detector. Using an amorphous silicon flat panel detector as the flat panel detector of the battery detection device can improve the detection efficiency and service life of the battery detection device.

[0019] In some embodiments, the pixel size L2 of the flat panel detector satisfies: L2≤100 μm. By limiting the pixel size L2 of the flat panel detector, the detection accuracy requirements of the battery to be tested can be met, while also improving the efficiency and accuracy of the detection.

[0020] In some embodiments, the pixel size L2 of the flat panel detector satisfies: 30 μm ≤ L2 ≤ 90 μm. By further limiting the pixel size L2 of the flat panel detector, the detection accuracy requirements of the battery to be tested are met, while further improving the detection efficiency and accuracy.

[0021] In some embodiments, the pixel size L2 of the flat panel detector satisfies: 70 μm ≤ L2 ≤ 80 μm. By further limiting the pixel size L2 of the flat panel detector, the efficiency and accuracy of detection are further improved.

[0022] In some embodiments, along a first direction, the distance h1 between the X-ray source and the supporting surface of the supporting assembly, and the distance h2 between the supporting surface of the supporting assembly and the flat-panel detector satisfy the relationship: (h1+h2) / h1≤2.5, where the first direction is perpendicular to the principal plane of the flat-panel detector. By defining the relationship between the distance between the X-ray source and the supporting surface of the supporting assembly, and the distance between the supporting surface of the supporting assembly and the flat-panel detector, the detection accuracy of the battery detection device can be better matched to the size of the flat-panel detector, while improving detection accuracy and efficiency.

[0023] In some embodiments, the distance h1 between the X-ray source and the supporting surface, and the distance h2 between the supporting surface and the flat-panel detector satisfy the relationship: 1.5 ≤ (h1 + h2) / h1 ≤ 2.0. By further defining the relationship between the distance between the X-ray source and the supporting surface of the supporting assembly, and the distance between the supporting surface of the supporting assembly and the flat-panel detector, the detection accuracy of the battery testing device can be further improved to match the size of the flat-panel detector, while further improving detection accuracy and efficiency.

[0024] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on the drawings without paying creative work.

[0026] FIG1 is a schematic structural diagram of a battery detection device according to some embodiments of the present application;

[0027] FIG2 is a schematic diagram of an imaging device for a battery detection device according to some embodiments of the present application;

[0028] FIG3 is a schematic structural diagram of a battery detection device according to some other embodiments of the present application;

[0029] FIG4 is a flow chart of a detection method of a battery detection device according to some embodiments of the present application;

[0030] FIG5 is a schematic diagram of a detection image of a battery under test according to some embodiments of the present application;

[0031] FIG6 is a schematic diagram of detection images of batteries to be tested according to other embodiments of the present application.

[0032] Description of reference numerals:

[0033] 100. Battery testing device; 110. Carrying assembly; 120. X-ray source; 130. Flat panel detector; 140. Battery to be tested. DETAILED DESCRIPTION

[0034] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0036] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0037] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0039] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0040] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0041] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0042] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0043] During the power battery production process, due to the numerous mechanical devices on the production line, metal debris is easily generated due to mechanical wear. Furthermore, since some battery production processes involve cutting and welding, this is even more prone to metal debris. This metal debris can fall into the battery casing, potentially posing a safety risk. For example, when metal debris reaches a certain size, sharp metal debris can pierce the separator, causing the battery to self-discharge. Metal debris can also pierce the blue film, causing a short circuit between adjacent battery cells within the battery, posing a safety risk.

[0044] Currently, the battery production process is being developed to reduce the amount of metal debris that falls into the battery casing by installing ventilation and dust collection devices and welding and gluing. However, these methods cannot completely eliminate metal debris, and there is still a risk of defective batteries flowing out.

[0045] In order to further reduce the risk of defective batteries being released, random inspections of batteries are performed using computed tomography (CT). However, this method takes a long time to image and is extremely inefficient, making it impossible to achieve full product inspection.

[0046] Based on this, it is necessary to propose a battery detection device based on the above technical problems to improve the efficiency of battery defect detection.

[0047] The battery testing equipment disclosed in the embodiments of the present application can be applied to battery cells and finished batteries, and can be applied to, but not limited to, the testing process in the battery production process.

[0048] FIG1 is a schematic structural diagram of a battery testing device 100 provided in some embodiments of the present application. As shown in FIG1 , the battery testing device 100 includes a carrier assembly 110 , an X-ray source 120 , and a flat panel detector 130 .

[0049] The carrier assembly 110 is used to support the battery under test 140, and the X-ray source 120 is used to irradiate X-rays to the battery under test 140 on the carrier assembly 110. The flat panel detector 130 and the X-ray source 120 are respectively located on either side of the carrier assembly 110. The flat panel detector 130 is used to receive the X-rays emitted by the X-ray source 120 and penetrate the battery under test 140.

[0050] In some embodiments of the present application, the carrying assembly 110 may be any carrying structure, and may fix the battery 140 to be tested by supporting or clamping, such as a tray, a clamp, etc. The carrying assembly 110 may be fixed or movable, such as a tray or a clamping mechanism provided with a conveying track and moving along the conveying track, which may convey the battery 140 to be tested to the inspection station in sequence and be removed again after the inspection is completed. The number of batteries 140 to be tested carried on the carrying assembly 110 may be one or more. In one example, the carrying assembly 110 may include multiple trays, each tray carrying one or more batteries 140 to be tested. The battery 140 to be tested may be a battery cell, or a battery including multiple battery cells, such as a square battery, a cylindrical battery, or a special-shaped battery.

[0051] In some embodiments of the present application, flat panel detector 130 is a device that converts received X-ray energy into a recordable electrical signal. It may be composed of three components: an X-ray conversion module, a photoelectric conversion module, and a signal readout and transmission module. Upon receiving X-rays of varying intensities, flat panel detector 130 generates an electrical signal proportional to the X-ray intensity. This allows flat panel detector 130 to capture information about the internal structure of objects penetrated by the X-rays and transmit this information to a processor in the form of a grayscale image, thereby detecting the object.

[0052] In some embodiments of the present application, the flat panel detector 130 is a two-dimensional flat panel detector, which can be either an indirect flat panel detector or a direct flat panel detector. The flat panel detector 130 is an X-ray imaging device. During the process of the battery testing device 100 testing the battery 140 to be tested, the battery 140 to be tested is located on the carrier assembly 110 and within the X-ray radiation area of ​​the X-ray source 120. The X-rays emitted by the X-ray source 120 pass through the battery 140 to be tested and are then projected onto the flat panel detector 130. The flat panel detector 130 receives the X-rays that have passed through the battery 140 to be tested and images the battery 140 to obtain a test image of the battery 140.

[0053] In some embodiments of the present application, the X-ray source 120 can be open (open tube) or closed (closed tube). The X-rays emitted by the X-ray source 120 will be absorbed and attenuated by the battery 140 when passing through it. Since the cathode and anode plates in the battery 140 are made of different materials, as well as metal debris that may exist inside the battery, different materials have different absorption rates for X-rays (the surface of the anode plate is carbon powder, which has weak absorption of X-rays; the surface of the cathode plate is lithium ion material, which has strong absorption of X-rays; and metal debris has even stronger absorption of X-rays). In addition, the absorption rates for X-rays by materials of different thicknesses are also different. The thicker the material, the greater the absorption of X-rays. Therefore, the inspection image of the battery 140 obtained by the flat panel detector 130 after receiving the X-rays passing through the battery 140 will show various defects of the battery 140, so that the inspection image of the battery 140 can be used to detect defects in the battery 140.

[0054] According to an embodiment of the present application, the battery to be tested 140 is placed on the carrier assembly 110, and the flat panel detector 130 and the X-ray source 120 are respectively located on both sides of the carrier assembly 110. The X-ray source 120 irradiates the battery to be tested 140 with X-rays, and the flat panel detector 130 receives the X-rays emitted by the X-ray source 120 and penetrating the battery to be tested 140 and forms an image based on the X-rays. Since different materials have different absorption rates of X-rays, the inspection image of the battery to be tested 140 obtained by the flat panel detector 130 receiving the X-rays passing through the battery to be tested 140 will show various defects of the battery to be tested 140, thereby effectively improving the efficiency of battery defect detection and preventing the outflow of risky products.

[0055] According to some embodiments of the present application, the focal spot size L1 of the X-ray source 120 satisfies: L1 ≤ 80 micrometers (μm).

[0056] In some embodiments of the present application, because the X-rays emitted by the X-ray source 120 are conical, the X-ray source 120 has a certain focal size and cannot be equivalent to a point light source. Therefore, when the battery testing device 100 is used to perform defect detection on the battery 140 to be tested, the imaging end of the battery 140 to be tested may be affected by the focal size of the X-ray source 120. When the focal size of the X-ray source 120 is larger, the detection image of the battery 140 to be tested becomes less clear. The size of defects in the battery 140 to be tested is generally small, and smaller defects are more sensitive to blur. Therefore, using an X-ray source 120 with a smaller focal size is more conducive to defect identification.

[0057] In some embodiments of the present application, the focal spot size of the X-ray source 120 refers to the size of the focal spot along a direction parallel to the plane on which the focal spot lies. Under the same conditions, the smaller the focal spot, the higher the resolution and the better the imaging quality. Common methods for measuring the focal spot size of the X-ray source 120 are divided into direct and indirect methods. Direct methods refer to directly observing the shape and size of the focal spot, such as the pinhole method. Indirect methods calculate the focal spot size by observing the point spread function or line spread function caused by the focal spot size, including the knife edge method, the slit method, and the ball target method. Testing can also be performed in accordance with methods specified in relevant measurement standards, such as the measurement methods listed in GB / T26834-2011.

[0058] For example, FIG2 is a schematic diagram of imaging of a battery testing device 100 according to some embodiments of the present application. As shown in FIG2 , the distance between the X-ray source 120 and the carrier assembly 110 is Da, the distance between the carrier assembly 110 and the flat-panel detector 130 is Db (the distance between the battery under test 140 and the flat-panel detector 130 can be approximately Db), and the focal spot size of the X-ray source 120 is L1. The image blur on the flat-panel detector 130 is U, where U = (L1*Db) / Da. The magnification of the battery under test 140 on the flat-panel detector 130 is M, where M = (Da+Db) / Da. Due to the limited imaging area of ​​the flat-panel detector 130, when using the battery testing device 100 to test the battery under test 140, the magnification M of the battery under test 140 is generally no more than 2.5 times, i.e., M ≤ 2.5. Therefore, the actual maximum imaging size of a 500 μm metal particle is 500*M = 1250 μm.

[0059] Furthermore, in order to facilitate the identification of defects in the battery 140 to be tested, the unsharpness U of the metal particle imaging generally needs to be less than 1 / 10 of the actual imaging size, that is, U = 1250μm / 10≤125μm. Since (Da+Db) / Da = M≤2.5, combined with U = (L1*Db) / Da, the focus size L1≤83μm can be obtained. Taking into account the scattering of ray photons and leaving some design redundancy, it is best to use an X-ray source 120 with a focus size L1≤80μm.

[0060] According to an embodiment of the present application, the size of the focal spot size L1 of the X-ray source 120 is directly related to the image resolution of the battery detection device 100. Specifically limiting the size of the focal spot size L1 of the X-ray source 120 can better match the detection accuracy of the battery detection device 100 with the size of the defects in the battery to be tested 140, thereby improving the detection accuracy and detection efficiency.

[0061] According to some embodiments of the present application, the focal spot size L1 of the X-ray source 120 satisfies: 30 μm ≤ L1 ≤ 80 μm.

[0062] In some embodiments of the present application, the X-ray source 120 generates a large amount of heat while emitting X-rays, causing the temperature to rise rapidly. Based on the heat dissipation of the X-ray source 120, a larger focal spot size L1 of the X-ray source 120 facilitates heat dissipation, thereby extending the service life of the X-ray source 120. Therefore, the focal spot size L1 of the X-ray source 120 should not be too small.

[0063] In the embodiment of the present application, by limiting the focal spot size L1 of the X-ray source 120 to satisfy: 30 μm ≤ L1 ≤ 80 μm, the service life of the X-ray source 120 can be extended while improving the detection accuracy and detection efficiency.

[0064] According to some embodiments of the present application, the focal spot size L1 of the X-ray source 120 satisfies: 40 μm ≤ L1 ≤ 70 μm.

[0065] In the embodiment of the present application, by limiting the focal spot size L1 of the X-ray source 120 to satisfy: 40 μm ≤ L1 ≤ 70 μm, the detection accuracy and efficiency can be further improved, and the service life of the X-ray source 120 can be further extended.

[0066] According to some embodiments of the present application, the focal spot size L1 of the X-ray source 120 satisfies: 50 μm ≤ L1 ≤ 60 μm.

[0067] In the embodiment of the present application, by limiting the focal spot size L1 of the X-ray source 120 to satisfy: 50 μm ≤ L1 ≤ 60 μm, the detection accuracy and efficiency can be further improved, and the service life of the X-ray source 120 can be further extended.

[0068] According to some embodiments of the present application, the power P of the X-ray source 120 satisfies: 65 watts (W) ≤ P ≤ 75W.

[0069] In some embodiments of the present application, increasing the X-ray dose requires increasing the power P of the X-ray source 120, which increases the workload of the X-ray source 120. Furthermore, increasing the power of the X-ray source 120 increases the focal spot size of the X-ray source 120. However, a larger focal spot size leads to a lower resolution of the flat panel detector 130. If the power P of the X-ray source 120 is reduced, the X-ray dose is reduced, and the detected image on the flat panel detector 130 becomes dim.

[0070] In the embodiment of the present application, the power P of the X-ray source 120 is limited to 65W≤P≤75W, which can improve the resolution of the flat panel detector 130 to a certain extent, and at the same time can improve the brightness of the detection image to a certain extent, thereby improving the accuracy of detection.

[0071] According to some embodiments of the present application, the power P of the X-ray source 120 satisfies: 68W≤P≤72W.

[0072] In the embodiment of the present application, the power P of the X-ray source 120 is further limited to 68W≤P≤72W, which can further improve the resolution of the flat panel detector 130, and at the same time further improve the brightness of the detected image and improve the accuracy of the detection device.

[0073] According to some embodiments of the present application, the operating voltage V of the X-ray source 120 satisfies: V≥130 kilovolts (kV), and / or the operating current I of the X-ray source satisfies: I≤500 microamperes (μA).

[0074] In some embodiments of the present application, the maximum photon energy emitted by the X-ray source 120 is equal to the energy acquired by the incident electron in the accelerating electric field of the X-ray tube—the electron charge multiplied by the accelerating electric field. The accelerating electric field is the magnitude of the tube voltage, which is also the magnitude of the operating voltage V of the X-ray source 120. The higher the operating voltage V, the higher the energy of the generated X-rays, the shorter the wavelength, and the greater the ability to penetrate matter.

[0075] In some embodiments of the present application, a higher operating current I of the X-ray source 120 results in more high-speed electrons bombarding the target per unit time, and more X-rays emitted by the X-ray source 120. This is equivalent to an increase in the X-ray dose per a given area, and a corresponding increase in image brightness. However, excessively high operating voltage V or current I of the X-ray source 120 can also result in an overly large focal spot size, thereby reducing the spatial resolution of the flat panel detector 130 and hindering subsequent image recognition and defect detection.

[0076] In some embodiments of the present application, the relationship between the intensity i of the X-ray source 120 and the operating voltage V and the operating current I of the X-ray source 120 is i=K*I*V n , where coefficient K depends on the high-voltage rectification method of X-ray source 120, and exponent n is determined by the operating voltage V of X-ray source 120 and the X-ray filtering conditions. The intensity i of the radiation emitted by X-ray source 120 is proportional to the operating current I of X-ray source 120 and to the Nth power of the operating voltage V of X-ray source 120.

[0077] In some embodiments of the present application, the X-ray attenuation relationship is i=i0e -μd When an X-ray with an intensity of i0 passes through a material with a thickness of d, the intensity I of the outgoing ray decays exponentially with the thickness; i is the intensity of the outgoing X-ray, i0 is the intensity of the incident X-ray, μ is the absorption coefficient of the material to the X-ray, and d is the distance the X-ray travels in the material.

[0078] In the embodiment of the present application, by limiting the operating voltage V and the operating current I of the X-ray source 120, it is possible to provide an X-ray dose that meets the requirements while taking into account the stability and reliability of the X-ray source 120. At the same time, the X-ray source 120 and the flat-panel detector 130 cooperate with each other to meet the requirements for the detection accuracy of the battery 140 to be tested, thereby improving the efficiency and accuracy of the detection.

[0079] According to some embodiments of the present application, the operating voltage V of the X-ray source 120 satisfies: V≥150 kV, and / or the operating current I of the X-ray source 120 satisfies: I≤400 μA.

[0080] In an embodiment of the present application, by further limiting the operating voltage V or operating current I of the X-ray source 120, the X-ray dose emitted by the X-ray source 120 is further increased, and at the same time, the stability and reliability of the X-ray source 120 are further improved, thereby improving the efficiency and accuracy of detection.

[0081] According to some embodiments of the present application, the flat panel detector 130 is an amorphous silicon flat panel detector.

[0082] In some embodiments of the present application, an amorphous silicon flat-panel detector (FPD) is used for indirect digital X-ray imaging. Its basic structure consists of a surface layer of scintillator material (cesium iodide or sulfur oxide), a layer below that of amorphous silicon photodiode circuitry, and a bottom layer of charge readout circuitry. The scintillator on the surface of the FPD converts X-rays into visible light. The amorphous silicon photodiode array beneath the scintillator converts the visible light into an electrical signal, forming a stored charge on the photodiode's own capacitor. The amount of stored charge in each pixel is proportional to the incident X-ray intensity. Under the control of a control circuit, the stored charge of each pixel is scanned and read out. After A / D conversion, the digital signal is output and transmitted to a computer for image processing, thereby forming a digital X-ray image.

[0083] In the embodiment of the present application, the amorphous silicon flat panel detector has high conversion efficiency, wide dynamic range and strong dose tolerance. Therefore, using an amorphous silicon flat panel detector as the flat panel detector 130 of the battery detection device 100 can improve the detection efficiency and service life of the battery detection device 100.

[0084] According to some embodiments of the present application, the pixel size L2 of the flat panel detector 130 satisfies: L2≤100 μm.

[0085] In some embodiments of the present application, the pixel size L2 of the flat panel detector 130 determines the resolution of the flat panel detector 130. The smaller the pixel size L2 of the flat panel detector 130, the higher the resolution of the flat panel detector 130. Conversely, the larger the pixel size L2 of the flat panel detector 130, the lower the resolution of the flat panel detector 130.

[0086] In some embodiments of the present application, after obtaining a test image of the battery 140 to be tested by the battery testing device 100, the test image can be identified by an algorithm to determine whether there is a defect inside the battery 140 to be tested. When the test image is identified by the algorithm, it is necessary to identify the defect features in the test image. The defect features can only be identified by the algorithm when the imaging range of the defect features is greater than or equal to 10 pixels. Usually, the defect size of the battery 140 to be tested is about 500μm. When the test image obtained by the battery testing device 100 is magnified 2 times, the defect imaging size of the battery 140 to be tested is 500μm*2=1000μm, and the pixel size of the flat panel detector 130 is less than or equal to 1000μm / 10=100μm. Therefore, the pixel size L2 of the flat panel detector 130 satisfies: L2≤100μm.

[0087] In the embodiment of the present application, by limiting the pixel size L2 of the flat panel detector 130 , the detection accuracy requirement for the battery to be tested 140 can be met, and the efficiency and accuracy of the detection can also be improved.

[0088] According to some embodiments of the present application, the pixel size L2 of the flat panel detector 130 satisfies: 30 μm≤L2≤90 μm.

[0089] In some embodiments of the present application, when the pixel size L2 of the flat panel detector 130 is too small, the amount of light entering a single pixel decreases, the received signal becomes weaker, and the signals between the pixels of the flat panel detector 130 interfere with each other, resulting in a decrease in the signal-to-noise ratio of the detected image imaged by the flat panel detector 130. Therefore, the pixel size L2 of the flat panel detector 130 cannot be too small.

[0090] In the embodiment of the present application, by further limiting the pixel size L2 of the flat panel detector 130 , the detection accuracy requirement for the battery to be tested 140 is met, while the detection efficiency and accuracy are further improved.

[0091] According to some embodiments of the present application, the pixel size L2 of the flat panel detector 130 satisfies: 70 μm≤L2≤80 μm.

[0092] In the embodiment of the present application, by further limiting the pixel size L2 of the flat panel detector 130 , the efficiency and accuracy of detection are further improved.

[0093] Figure 3 is a structural schematic diagram of a battery detection device 100 according to other embodiments of the present application. Referring to Figures 1 and 3, along a first direction (Y direction in the figures), a distance h1 between the X-ray source 120 and the bearing surface of the bearing assembly 110, and a distance h2 between the bearing surface of the bearing assembly 110 and the flat panel detector 130 satisfy the relationship: (h1+h2) / h1≤2.5, wherein the first direction is a direction perpendicular to the main plane of the flat panel detector 130.

[0094] In some embodiments of the present application, when the battery testing apparatus 100 is used to test the battery 140 under test, the magnification factor M of the battery 140 under test is associated with the distance h1 between the X-ray source 120 and the supporting surface of the supporting assembly 110, and the distance h2 between the supporting surface of the supporting assembly 110 and the flat-panel detector 130, where M = (h1 + h2) / h1. Due to the limited imaging area of ​​the flat-panel detector 130, when the battery testing apparatus 100 is used to test the battery 140 under test, the magnification factor M of the battery 140 under test is generally no more than 2.5 times, i.e., (h1 + h2) / h1 ≤ 2.5.

[0095] In the embodiment of the present application, the relationship between the distance between the X-ray source 120 and the bearing surface of the bearing assembly 110, and the distance between the bearing surface of the bearing assembly 110 and the flat-panel detector 130 is directly related to the magnification factor of the battery 140 to be tested. By limiting the relationship between the distance between the X-ray source 120 and the bearing surface of the bearing assembly 110, and the distance between the bearing surface of the bearing assembly 110 and the flat-panel detector 130, the detection accuracy of the battery detection device 100 can be better matched with the size of the flat-panel detector 130, while improving the accuracy and efficiency of the detection.

[0096] According to some embodiments of the present application, the distance h1 between the X-ray source 120 and the carrying surface and the distance h2 between the carrying surface and the flat panel detector 130 satisfy the relationship: 1.5≤(h1+h2) / h1≤2.0.

[0097] In the embodiment of the present application, by further limiting the relationship between the distance between the X-ray source 120 and the bearing surface of the bearing assembly 110, and the distance between the bearing surface of the bearing assembly 110 and the flat-panel detector 130, the detection accuracy of the battery detection device 100 can be further better matched with the size of the flat-panel detector 130, while further improving the accuracy and efficiency of the detection.

[0098] The battery detection device of the present application is further described below with reference to a specific embodiment.

[0099] The battery testing device 100 includes a carrier assembly 110, an X-ray source 120, and a flat-panel detector 130. The flat-panel detector 130 and the X-ray source 120 are located on either side of the carrier assembly 110. The carrier assembly 110 is used to support a battery 140 under test. The X-ray source 120 is used to irradiate the battery 140 under test on the carrier assembly 110 with X-rays. The flat-panel detector 130 is used to receive X-rays emitted by the X-ray source 120 and that have penetrated the battery 140 under test. Along a direction perpendicular to the main plane of the flat-panel detector 130, the distance h1 between the X-ray source 120 and the carrier surface of the carrier assembly 110, and the distance h2 between the carrier surface of the carrier assembly 110 and the flat-panel detector 130 satisfy the relationship: 1.5 ≤ (h1 + h2) / h1 ≤ 2.0.

[0100] The focal spot size L1 of the X-ray source 120 satisfies the following conditions: 50 μm ≤ L1 ≤ 60 μm; the power P of the X-ray source 120 satisfies the following conditions: 68 W ≤ P ≤ 72 W; the operating voltage V of the X-ray source 120 satisfies the following conditions: V ≥ 150 kV, and / or the operating current I of the X-ray source 120 satisfies the following conditions: I ≤ 400 μA. The flat panel detector 130 is an amorphous silicon flat panel detector, and the pixel size L2 of the flat panel detector 130 satisfies the following conditions: 70 μm ≤ L2 ≤ 80 μm.

[0101] FIG4 is a flow chart of a detection method of a battery detection device according to some embodiments of the present application. As shown in FIG4 , the detection method of the battery detection device 100 includes the following steps:

[0102] Step S401: calibrate the flat panel detector.

[0103] To ensure image quality, the flat-panel detector 130 must be calibrated before powering on. Before calibration, ensure there are no obstructions between the X-ray source 120 and the flat-panel detector 130, including the carrier assembly 110 and any debris. Turn on the X-ray source 120 to capture bright-field images. Afterward, turn off the X-ray source 120 to capture dark-field images. Repeat this process three times, capturing 19 images each time. After calibration, reactivate the calibration template.

[0104] Step S402: calibrating the detection device.

[0105] Before calibration, ensure that there are no batteries 140 to be tested or any other debris between the X-ray source 120 and the flat-panel detector 130. Place the calibration block provided with the equipment on the test platform and adjust the scale of the calibration block so that the height of the pin gauge mounted on the calibration block is half the height of the battery 140 to be tested. Turn off the equipment, turn on the X-ray source 120, and move the pin gauge to the center of the image. Maintaining the relative position of the X-ray source 120 and flat-panel detector 130 consistent with that used during the battery test, open the software calibration interface and enter the pin gauge diameter. The software will automatically record and save the magnification factor.

[0106] Step S403: transport the battery to be tested to a testing station.

[0107] The carrier assembly 110 is driven to move, and the batteries to be tested 140 are sequentially transferred to the detection position between the X-ray source 120 and the flat panel detector 130 and then stops moving, waiting for X-rays to be turned on and detected.

[0108] Step S404: Start X-ray detection and save the image.

[0109] After setting the operating voltage V and current I of the X-ray source 120 for testing, the X-ray source 120 is turned on to transmit the X-rays through the battery 140 under test. The flat panel detector 130 receives the X-rays that penetrate the battery 140 under test and converts them into an image. The processor then reads and saves the image. Figure 5 is a schematic diagram of a test image of the battery 140 under test according to some embodiments of the present application, and Figure 6 is a schematic diagram of a test image of the battery 140 under test according to other embodiments of the present application.

[0110] Step S405: The algorithm identifies whether there are defects in the image.

[0111] Through a deep learning algorithm, the metal particle features in the image are captured and identified. If the metal particle features are present in the image, step S406 is executed, the image is judged as NG, and the corresponding battery 140 to be tested is automatically rejected to prevent bad products from being discharged. For example, as shown in FIG5 , a metal particle feature is present at position P1 in the image. FIG6 is a schematic diagram of the detection image of the battery 140 to be tested in other embodiments of the present application. As shown in FIG6 , a metal particle feature is present at position P2 in the image. If the metal particle features are not present in the image, step S407 is executed, the image is judged as OK, and the corresponding battery 140 to be tested is discharged normally.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery detection device, comprising: A carrying component, used for carrying the battery to be tested; An X-ray source, used for irradiating X-rays to the battery to be tested on the carrier assembly; A flat panel detector, wherein the flat panel detector and the X-ray source are respectively located on two sides of the bearing assembly, and the flat panel detector is used to receive rays emitted by the X-ray source and penetrating the battery to be tested.

2. The battery testing device according to claim 1, wherein: The focal spot size L1 of the X-ray source satisfies: L1≤80 μm.

3. The battery testing device according to claim 2, wherein: The focal spot size L1 of the X-ray source satisfies: 30 μm≤L1≤80 μm.

4. The battery testing device according to claim 3, wherein: The focal spot size L1 of the X-ray source satisfies: 40 μm≤L1≤70 μm.

5. The battery testing device according to claim 4, wherein: The focal spot size L1 of the X-ray source satisfies: 50 μm≤L1≤60 μm.

6. The battery testing device according to any one of claims 1 to 5, wherein: The power P of the X-ray source satisfies: 65W≤P≤75W.

7. The battery testing device according to claim 6, wherein: The power P of the X-ray source satisfies: 68W≤P≤72W.

8. The battery testing device according to any one of claims 1 to 7, wherein: The operating voltage V of the X-ray source satisfies: V≥130 kV, and / or the operating current I of the X-ray source satisfies: I≤500 μA.

9. The battery testing device according to claim 8, wherein: The operating voltage V of the X-ray source satisfies: V≥150 kV, and / or the operating current I of the X-ray source satisfies: I≤400 μA.

10. The battery testing device according to any one of claims 1 to 9, wherein: The flat panel detector is an amorphous silicon flat panel detector.

11. The battery testing device according to any one of claims 1 to 10, wherein: The pixel size L2 of the flat panel detector satisfies: L2≤100 μm.

12. The battery testing device according to claim 11, wherein: The pixel size L2 of the flat panel detector satisfies: 30 μm≤L2≤90 μm.

13. The battery testing device according to claim 12, wherein: The pixel size L2 of the flat panel detector satisfies: 70 μm≤L2≤80 μm.

14. The battery testing device according to any one of claims 1 to 13, wherein: Along the first direction, the distance h1 between the X-ray source and the bearing surface of the bearing assembly, and the distance h2 between the bearing surface of the bearing assembly and the flat panel detector satisfy the relationship: (h1+h2) / h1≤2.5 The first direction is a direction perpendicular to the main plane of the flat panel detector.

15. The battery testing device according to claim 14, wherein: The distance h1 between the X-ray source and the bearing surface and the distance h2 between the bearing surface and the flat panel detector satisfy the relationship: 1.5≤(h1+h2) / h1≤2.0.

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