Gap Detection Device and Gap Detection Method

Abstract

The present application provides a gap detection device and a gap detection method. The gap detection device is used for winding electric cores. In the height direction of the wound electric core, the wound electric core includes a wound body part and a tab connected to each other. The gap detection device includes: an X-ray source and an X-ray detector arranged oppositely, and a carrying mechanism located between the X-ray source and the X-ray detector; wherein, the carrying mechanism includes at least one accommodating groove for accommodating the wound electric core, and the height direction of the wound electric core intersects with a first direction in which the X-ray source points to the X-ray detector; the X-ray source is used for irradiating an arc area of the wound body part, and the X-ray detector is used for obtaining an imaging image of the irradiated arc area, so as to obtain a gap value between two pole pieces in the arc area based on the imaging image. Through this design method, the gap value between two pole pieces of the wound electric core can be detected simply and efficiently.

Description

Technical Field

[0001] This application belongs to the technical field of battery cell detection, and particularly relates to a gap detection device and a gap detection method. Background Art

[0002] With the rapid development of the new energy industry, electric vehicles powered by lithium-ion batteries have begun to be widely used. The quality of power batteries not only affects the lifespan of power batteries, but also affects driving safety.

[0003] Among them, a power battery is composed of several battery cells. During the cycling process of the power battery, the gap value between the positive electrode tab and the negative electrode tab of the battery cell is an important factor affecting the migration of lithium ions. For example, when the gap value is large, phenomena such as lithium ion accumulation and lithium deposition are likely to occur, resulting in safety risks. Therefore, it is necessary to accurately detect the gap value during the production process of power batteries. Summary of the Invention

[0004] This application provides a gap detection device and a gap detection method to simply and efficiently detect the gap value between two electrode tabs of a wound battery cell.

[0005] To solve the above technical problems, a technical solution adopted by this application is: to provide a gap detection device for a wound battery cell. In the height direction of the wound battery cell, the wound battery cell includes a wound body part and a tab connected to each other. The gap detection device includes: an X-ray source and an X-ray detector arranged oppositely, and a carrying mechanism located between the X-ray source and the X-ray detector; wherein, the carrying mechanism includes at least one accommodation groove for accommodating the wound battery cell, and the height direction of the wound battery cell intersects with the first direction in which the X-ray source points to the X-ray detector; the X-ray source is used to irradiate the arc-shaped area of the wound body part, and the X-ray detector is used to obtain an imaging image of the irradiated arc-shaped area, so as to obtain the gap value between the two electrode tabs in the arc-shaped area based on the imaging image.

[0006] Through the above gap detection device, processes such as multi-angle image acquisition, three-dimensional reconstruction, and CT tomogram screenshot of the wound battery cell are not required. The imaging image of the arc-shaped area of the wound battery cell can be directly obtained through the X-ray source and the X-ray detector, and the gap value between the two electrode tabs in the arc-shaped area can be obtained. The detection process is relatively simple and efficient.

[0007] In some embodiments, the carrying mechanism includes a carrier and a buffer fixing member. The side of the carrier facing the X-ray source or the X-ray detector includes an accommodation cavity, the buffer fixing member is located in the accommodation cavity, and the buffer fixing member is provided with an accommodation groove. The structure of the above carrying mechanism 4 is relatively simple and easy to prepare.

[0008] In some embodiments, in the first direction, the accommodating groove passes through the buffer fixing member. This design method can reduce the influence of the buffer fixing member on the imaging effect of the wound battery core.

[0009] And / or, the Shore hardness of the buffer fixing part is greater than or equal to 40 degrees and less than or equal to 50 degrees. This design method can make the buffer fixing part have both the effect of limiting and reducing damage.

[0010] And / or, the buffer fixing member includes foam. The buffer fixing member made of this material has the advantages of good X-ray penetration and light weight, so as to reduce the influence of the buffer fixing member on the imaging effect of the wound battery core.

[0011] In some embodiments, the accommodating groove includes a first sub-accommodating groove and a second sub-accommodating groove that are interconnected, the first sub-accommodating groove is used to accommodate the winding body, and the second sub-accommodating groove is used to accommodate the tab; wherein there is a preset interval between the winding body and the inner wall of the first sub-accommodating groove, and between the tab and the inner wall of the second sub-accommodating groove. This design method can reduce the damage of the accommodating groove to the wound battery cell.

[0012] In some embodiments, there are two tabs, which are arranged on the same side of the winding body; the second sub-accommodation groove is used to accommodate the two tabs. This design method can reduce the difficulty of alignment during the placement process.

[0013] In some embodiments, in the second direction, two opposite sides of the first sub-receiving groove are respectively provided with a pick-up and release groove; wherein the second direction is perpendicular to the third direction from the first sub-receiving groove to the second sub-receiving groove, and the size of the receiving groove in the third direction is larger than the size of the pick-up and release groove. The introduction of the pick-up and release groove can reduce the difficulty of picking up and placing the wound battery cell and reduce the damage to the wound battery cell.

[0014] In some embodiments, the buffer fixing member is provided with a first foolproof portion, and the accommodating cavity is provided with a second foolproof portion, and the first foolproof portion and the second foolproof portion cooperate with each other. This design method can reduce the probability of placing the buffer fixing member in the wrong direction in the carrier, thereby improving the detection efficiency.

[0015] In some embodiments, the carrier includes a bottom plate and side plates connected to each other, and the side plates are arranged around the bottom plate to form a receiving cavity; wherein the material of the bottom plate includes carbon fiber, and the material of the side plates includes metal. The bottom plate of the above material can reduce the impact on the imaging effect of the wound battery cell; the side plates of the above material can make the bottom plate have a certain load-bearing capacity, and the side plates play a role in limiting the buffer fixing member, which is conducive to improving the limiting effect of the buffer fixing member on the wound battery cell.

[0016] In some embodiments, the carrier also includes two handles arranged opposite to each other, which are located on the outer surface of the side plate away from the accommodating cavity. The handles are designed to facilitate transportation.

[0017] To solve the above technical problems, another technical solution adopted by this application is: to provide a gap detection method, which uses the gap detection device in any of the above embodiments. This gap detection method includes: placing the wound battery cell in the accommodation groove of the bearing mechanism, and setting the bearing mechanism between the relatively arranged X-ray source and X-ray detector; wherein, in the height direction of the wound battery cell, the wound battery cell includes a wound body part and a tab that are connected to each other, and the height direction of the wound battery cell intersects with the first direction in which the X-ray source points to the X-ray detector; making the X-ray source irradiate the arc area of the wound body part, and the X-ray detector obtains the imaging image of the arc area; obtaining the gap value between two pole pieces in the arc area based on the imaging image.

[0018] In some embodiments, the wound body part includes alternately arranged positive pole pieces and negative pole pieces; the step of obtaining the gap value between two pole pieces in the wound body part in the arc area based on the imaging image includes: preprocessing the imaging image, and obtaining the target area from the preprocessed imaging image; determining the position information of the positive pole piece and the negative pole piece from the target area based on the size information of the positive pole piece and the negative pole piece; obtaining the gap value between the adjacent positive pole piece and negative pole piece from the target area based on the position information of the positive pole piece and the negative pole piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings, where:

[0020] Figure 1 It is a schematic structural diagram of an embodiment of a wound battery cell;

[0021] Figure 2 is Figure 1 A schematic cross-sectional view of the wound battery cell along the A-A section line in one embodiment;

[0022] Figure 3 It is a schematic structural diagram of another embodiment of a wound battery cell;

[0023] Figure 4 It is a schematic structural diagram of an embodiment of the gap detection device of this application;

[0024] Figure 5 is Figure 4 An exploded schematic diagram of the bearing mechanism in one embodiment;

[0025] Figure 6 is Figure 4Structural schematic diagram of another embodiment of the middle buffer fixing member;

[0026] Figure 7 is Figure 4 Structural schematic of another embodiment of the middle buffer fixing member;

[0027] Figure 8 Flow schematic diagram of one embodiment of the gap detection method of this application;

[0028] Figure 9 is Figure 8 Flow schematic diagram of one embodiment corresponding to step S103 in the middle;

[0029] Figure 10 is after Figure 9 Schematic diagram of one embodiment of the target area after step S201 in the middle;

[0030] Specific attached drawing reference numerals are as follows:

[0031] Wound battery cell 1, wound body part 10, tab 12;

[0032] Positive electrode plate 100, negative electrode plate 102, separator 104, positive tab 120, negative tab 122, arc area 106, flat area 108;

[0033] Positive current collector 1000, positive active material layer 1002, negative current collector 1020, negative active material layer 1022;

[0034] Gap detection device 2, X-ray source 20, X-ray detector 22, carrying mechanism 24;

[0035] Receiving groove 240, carrier 242, buffer fixing member 244, receiving cavity 246, pick-and-place groove 248, first anti-fooling part 241, second anti-fooling part 243;

[0036] Bottom plate 2420, side plate 2422, handle 2424, first sub-receiving groove 2400, second sub-receiving groove 2402;

[0037] Height direction P1 of the wound battery cell 1, width direction P2 of the wound battery cell 1, thickness direction P3 of the wound battery cell 1, first direction L1, second direction L2, third direction L3. Specific embodiments

[0038] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0039] 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 belongs; the terms used herein are for the purpose of describing specific embodiments only 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 description of the drawings are intended to cover non-exclusive inclusion.

[0040] In the description of the embodiments of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of this application, "a plurality of" means two or more unless otherwise specifically defined.

[0041] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0042] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0043] In the description of the embodiments of this application, the term "a plurality of" refers to two or more (including two). Similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0044] In the description of the embodiments of this application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of this application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of this application.

[0045] In the description of the embodiments of the present application, unless otherwise clearly defined and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0046] At present, from the perspective of the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric vehicles, as well as in many fields such as military equipment and aerospace. With the continuous expansion of the application fields of power batteries, the market demand is also continuously increasing; among them, power batteries composed of wound battery cells are particularly widely used.

[0047] Please refer to Figure 1 and Figure 2 , Figure 1 is a schematic structural diagram of an embodiment of a wound battery cell, Figure 2 is Figure 1 a schematic cross-sectional view of the wound battery cell along the A-A section line in an embodiment. First, it is defined that the wound battery cell 1 includes a height direction P1, a width direction P2, and a thickness direction P3 that are perpendicular to each other in pairs. In the height direction P1 of the wound battery cell 1, the wound battery cell 1 includes a wound body part 10 and a tab 12 that are connected to each other. Among them, the wound body part 10 is generally formed by winding a positive electrode tab 100 and a negative electrode tab 102, and a separator 104 is provided between the positive electrode tab 100 and the negative electrode tab 102. The positive electrode tab 100 includes a positive electrode current collector 1000 and a positive electrode active material layer 1002 coated on the surface of the positive electrode current collector 1000, and the negative electrode tab 102 includes a negative electrode current collector 1020 and a negative electrode active material layer 1022 coated on the surface of the negative electrode current collector 1020. At this time, the corresponding tab 12 includes a positive electrode tab 120 and a negative electrode tab 122, the positive electrode tab 120 is connected to the positive electrode tab 100, and the negative electrode tab 122 is connected to the negative electrode tab 102. As Figure 1 shown, the positive electrode tab 120 and the negative electrode tab 122 can be located on the same side of the wound body part 10. Of course, in other embodiments, the positive electrode tab 120 and the negative electrode tab 122 can also be located on opposite sides of the wound body part 10, and the present application does not limit this. In addition, as Figure 1 shown, the wound body part 10 of the wound battery cell 1 can be square; of course, in other embodiments, such as Figure 3As shown, the winding body portion 10 of the wound battery cell 1 can also be cylindrical, and the present application does not limit this.

[0048] Furthermore, as Figure 1 , Figure 2 and Figure 3 shown, the winding body portion 10 includes an arc region 106, and the arc region 106 can be any region on the winding body portion 10 that has a curvature (i.e., is non-planar). For example, Figure 1 at the left and right corners of the winding body portion 10 in Figure 2 ; or for example, the winding body portion 10 at any position in

[0049] The inventors of the present application have noticed that for the wound battery cell 1, during the winding process of the wound battery cell 1, due to the different forces on the inner and outer radii of the arc region 106, the gap value between the negative electrode tab 102 and the positive electrode tab 100 in the inner circle is likely to be too large after hot pressing. And currently, the following CT slice detection method is generally used for testing the gap value of the wound battery cell 1: image acquisition of the wound battery cell 1 from multiple angles, and three-dimensional reconstruction based on the multiple acquired images; then the three-dimensionally reconstructed model is intercepted to obtain a CT tomogram in a preset direction, and the corresponding gap value is obtained based on this CT tomogram. Obviously, this detection method has the problems of low detection efficiency and high detection cost.

[0050] To solve the above technical problems, please refer to Figure 4 , Figure 4 which is a schematic structural diagram of an embodiment of the gap detection device of the present application. This gap detection device 2 is used to detect the gap value of the above-mentioned wound battery cell 1, and it includes an X-ray source 20, an X-ray detector 22, and a carrying mechanism 24. Among them, the X-ray source 20 and the X-ray detector 22 are relatively and spaced apart, and the carrying mechanism 24 is located between the X-ray source 20 and the X-ray detector 22. Among them, the carrying mechanism 24 includes at least one accommodation groove 240, and the accommodation groove 240 is used to accommodate the wound battery cell 1, and during detection, the height direction P1 of the wound battery cell 1 intersects with the first direction L1 in which the X-ray source 20 points to the X-ray detector 22; the X-ray source 20 is used to irradiate the arc region 106 of the winding body portion 10 (such as Figure 1 , Figure 2 , Figure 3 marked), and the X-ray detector 22 is used to obtain the imaging image of the irradiated arc region 106, so as to obtain the gap value between the two electrode tabs in the arc region 106 based on the imaging image.

[0051] Specifically, the above-mentioned X-ray source 20 refers to a device capable of emitting X-rays. The X-ray detector 22 can be a flat panel detector, which can convert the received X-ray energy into a recordable electrical signal. By measuring the amount of X-rays it receives, it generates an electrical signal proportional to the X-rays, and then forms a corresponding image. Optionally, the X-ray detector 22 can include three parts: an X-ray conversion module, a photoelectric conversion module, and a signal reading and transmission module. During the test of the gap detection device 2, the electrons emitted from the cathode in the X-ray source 20 are accelerated by the electric field between the cathode and the anode, bombard the X-ray source target, transfer their kinetic energy to the atoms on the target, and about 1% of the energy is converted into X-rays and emitted from the X-ray irradiation window; the emitted X-rays penetrate the wound battery cell 1 and are imaged by the X-ray detector 22.

[0052] In an application scenario, as Figure 2 shown, the detection resolution requirement for the gap value d between the adjacent negative electrode tab 102 and the positive electrode tab 100 in the wound battery cell 1 is less than 20 microns. To meet this detection requirement, on the one hand, the X-ray source 20 in this application selects an integrated microfocus X-ray source. Generally speaking, the smaller the focus size of the X-ray source 20, the higher the resolution of the imaging image and the clearer the imaging picture. The integrated microfocus X-ray source has the advantages of high stability, low repair rate, small volume, convenient operation and installation, and is suitable for use in production lines. And in this application, to improve the X-ray transmittance and the signal-to-noise ratio of the imaging image of the wound battery cell 1, a 150KV microfocus X-ray source is adopted. On the other hand, in this application, the pixel size of the X-ray detector 22 divided by the magnification factor needs to be less than 20 microns. Optionally, when the magnification factor is greater than or equal to 5 times, the pixel size of the X-ray detector 22 is less than or equal to 100 microns.

[0053] The intersection of the height direction P1 of the above-mentioned wound battery cell 1 and the first direction L1 in which the X-ray source 20 points to the X-ray detector 22 means that the wound battery cell 1 is placed between the X-ray source 20 and the X-ray detector 22 in a lying manner. Preferably, the height direction P1 of the wound battery cell 1 is perpendicular to the first direction L1, the first direction L1 is parallel to the thickness direction P3 of the wound battery cell 1, and the X-rays emitted by the X-ray source 20 can penetrate the wound battery cell 1 from the thickness direction P3 of the wound battery cell 1.

[0054] Please refer to again Figure 2 , the arc area 106 can include any area with an arc (i.e., non-planar) in the wound body part 10. In the thickness direction P3, the adjacent positive electrode tab 100 and negative electrode tab 102 in the arc area 106 are not completely blocked from each other. After being irradiated by the X-ray source 20, the X-ray detector 22 can obtain the imaging images of the positive electrode tab 100 and the negative electrode tab 102 arranged at intervals in the arc area 106. In addition, asFigure 1 and Figure 2 As shown in Figure 2 , when the winding body portion 10 further includes a flat region 108, in the thickness direction P3, the adjacent positive electrode plates 100 and negative electrode plates 102 completely block each other. After being irradiated by the X-ray source 20, the adjacent positive electrode plates 100 and negative electrode plates 102 overlap each other in the imaging image obtained by the X-ray detector 22, and the gap value d between the positive electrode plate 100 and the negative electrode plate 102 cannot be accurately obtained. That is, the X-ray source 20 in the gap detection device 2 provided in the present application must irradiate the arc region 106 of the winding body portion 10.

[0055] In addition, it can be known that after the X-ray detector 22 obtains the imaging image of the irradiated arc region 106, the gap value between any two electrode plates in the arc region 106 can be obtained based on this imaging image. The any two electrode plates can be the adjacent positive electrode plate 100 and negative electrode plate 102, or two adjacent and spaced positive electrode plates 100, or two adjacent and spaced negative electrode plates 102. In addition, the any two electrode plates can be located at the innermost side of the arc region 106 or at other positions in the arc region 106, and the present application does not make any limitations thereto.

[0056] In summary, through the above gap detection device 2, it is not necessary to perform processes such as multi-angle image acquisition, three-dimensional reconstruction, and CT tomogram screenshot of the wound battery cell 1. The imaging image of the arc region 106 of the wound battery cell 1 can be directly obtained through the X-ray source 20 and the X-ray detector 22, and the gap value between the two electrode plates in the arc region 106 can be obtained. The detection process is relatively simple and has high efficiency.

[0057] Please refer to Figure 5 , Figure 5 which Figure 4 is an exploded schematic view of an embodiment of the bearing mechanism in Figure 4 . The bearing mechanism 24 includes a bearing member 242 and a buffer fixing member 244. The side of the bearing member 242 facing the X-ray source 20 or the X-ray detector 22 includes a receiving cavity 246. The buffer fixing member 244 is located in the receiving cavity 246, and a receiving groove 240 is provided on the buffer fixing member 244. The structure of the above bearing mechanism 24 is relatively simple and easy to prepare.

[0058] Specifically, the statement that the side of the bearing member 242 facing the X-ray source 20 or the X-ray detector 22 includes a receiving cavity 246 means that when the X-ray source 20 is located above the bearing mechanism 24 and the X-ray detector 22 is located below the bearing mechanism 24, the side of the bearing member 242 facing the X-ray source 20 above it includes a receiving cavity 246. When the X-ray detector 22 is located above the bearing mechanism 24 and the X-ray source 20 is located below the bearing mechanism 24, the side of the bearing member 242 facing the X-ray detector 22 above it includes a receiving cavity 246.

[0059] The accommodating cavity 246 is an unclosed chamber, and the accommodating cavity 246 has an opening facing the X-ray source 20 or the X-ray detector 22. On the one hand, the buffer fixing member 244 and the winding battery cell 1 to be measured can easily enter and exit the carrier 242 from the opening; on the other hand, the blocking effect of the carrier 242 on the X-ray can be reduced to improve the subsequent imaging effect. When the side of the carrier 242 facing the X-ray source 20 includes the accommodating cavity 246, the X-ray emitted by the X-ray source 20 will sequentially penetrate the winding battery cell 1 and the carrier 242 on one side of the winding battery cell 1; when the side of the carrier 242 facing the X-ray detector 22 includes the accommodating cavity 246, the X-ray emitted by the X-ray source 20 will sequentially penetrate the carrier 242 on one side of the winding battery cell 1 and the winding battery cell 1.

[0060] As Figure 5 shown, the carrier 242 includes a bottom plate 2420 and side plates 2422 that are connected to each other, and the side plates 2422 surround the periphery of the bottom plate 2420 to form the accommodating cavity 246, that is, the side plates 2422 are in a ring structure at this time. The structural design of the carrier 242 is relatively simple and easy to prepare and form.

[0061] Optionally, the material of the bottom plate 2420 includes carbon fiber. At this time, the bottom plate 2420 is formed by infiltrating and hardening carbon fibers arranged in the same direction with resin to form a carbon fiber plate, which has the advantages of low density, good X-ray penetrability, light weight, good flexibility, good durability and corrosion resistance, etc.; that is, the bottom plate 2420 of this material can reduce the influence on the imaging effect of the winding battery cell 1. Preferably, the thickness of the bottom plate 2420 in the first direction L1 is 1.5 mm - 2.5 mm (for example, 2 mm, etc.).

[0062] Another option is that the material of the side plates 2422 includes metal (such as stainless steel, etc.). Since the side plates 2422 will not affect the imaging effect of the winding battery cell 1, the requirement for the X-ray penetrability of the side plates 2422 is not high. The side plates 2422 made of the above metal material can fix the bottom plate 2420, make the bottom plate 2420 have a certain load-bearing capacity, and the side plates 2422 play a role in limiting the buffer fixing member 244, which is beneficial to improving the limiting effect of the buffer fixing member 244 on the winding battery cell 1, and further can improve the accuracy of the detection position.

[0063] Another option is that the carrier 242 further includes two handles 2424 that are oppositely arranged on the outer surface of the side plates 2422 facing away from the accommodating cavity 246. The design of the handles 2424 can facilitate handling. Preferably, the material of the handles 2424 is metal, and the handles 2424 can be integrally formed with the side plates 2422. In addition, the shape of the handles 2424 can be arc-shaped, etc., for easy grasping.

[0064] The above-mentioned buffer fixing member 244 refers to a member that can undergo a certain deformation and play a role in limiting and fixing the position of the wound battery cell 1. On the one hand, when the device shakes or moves, the buffer fixing member 244 can buffer stress through its own deformation, reducing the probability of the position of the wound battery cell 1 shifting. On the other hand, when the wound battery cell 1 is taken and placed, the buffer fixing member 244 has little interference with the wound battery cell 1, and can reduce the damage to the wound battery cell 1.

[0065] Optionally, the buffer fixing member 244 includes foam; for example, its material is EVA (ethylene-vinyl acetate copolymer), etc. The buffer fixing member 244 made of this material has advantages such as good X-ray penetrability and light weight, so as to reduce the influence of the buffer fixing member 244 on the imaging effect of the wound battery cell 1.

[0066] Another optionally, the Shore hardness of the buffer fixing member 244 is greater than or equal to 40 degrees and less than or equal to 50 degrees; for example, the Shore hardness of the buffer fixing member 244 is 45 degrees, etc. Generally speaking, the lower the hardness, the greater the deformation ability of the buffer fixing member 244, and the worse the limiting effect on the wound battery cell 1; while the higher the hardness, the greater the probability of the buffer fixing member 244 causing damage to the wound battery cell 1 when the wound battery cell 1 is taken and placed. Therefore, considering the two aspects comprehensively, the buffer fixing member 244 with the above-mentioned Shore hardness range is designed so that the buffer fixing member 244 can take into account both the limiting and damage reduction effects.

[0067] Yet another optionally, in the first direction L1, the accommodating groove 240 penetrates through the buffer fixing member 244; that is, the bottom plate 2420 is exposed from the accommodating groove 240. Compared with the case where the accommodating groove 240 does not penetrate through the buffer fixing member 244, in this design, the X-ray only needs to penetrate the arc-shaped area 106 of the wound battery cell 1 and the bottom plate 2420 at the corresponding position and then be received by the X-ray detector 22, so as to reduce the influence of the buffer fixing member 244 on the imaging effect of the wound battery cell 1.

[0068] Please continue to refer to Figure 4 and Figure 5 , the accommodating groove 240 includes a first sub-accommodating groove 2400 and a second sub-accommodating groove 2402 that are communicated with each other. The first sub-accommodating groove 2400 is used to accommodate the wound body part 10, and the second sub-accommodating groove 2402 is used to accommodate the pole ear 12. Among them, there is a preset interval between the wound body part 10 and the inner wall of the first sub-accommodating groove 2400, and between the pole ear 12 and the inner wall of the second sub-accommodating groove 2402. That is to say, the size of the accommodating groove 240 is larger than the size of the wound battery cell 1 that it needs to accommodate, so as to reduce the damage of the accommodating groove 240 to the wound battery cell 1.

[0069] Optionally, the preset interval is 0.5 mm - 1.5 mm (for example, 1 mm, etc.). In this design method, the size of the accommodation groove 240 is slightly larger than the size of the wound battery cell 1 to be accommodated therein, which can reduce the damage of the accommodation groove 240 to the wound battery cell 1 while ensuring the limiting effect of the buffer fixing member 244 on the wound battery cell 1.

[0070] Another option is, as Figure 4 shown, to define two mutually perpendicular second direction L2 and third direction L3; wherein, the direction from the first sub-accommodation groove 2400 to the second sub-accommodation groove 2402 is the third direction L3, the third direction L3 is parallel to the height direction P1 of the wound battery cell 1, and the second direction L2 is parallel to the width direction P2 of the wound battery cell 1. Generally speaking, in the second direction L2, the width of the winding body part 10 is greater than the width of the tab 12. Correspondingly, the width of the first sub-accommodation groove 2400 is greater than the width of the second sub-accommodation groove 2402.

[0071] Please refer to Figure 1 and Figure 6 , Figure 6 which is Figure 4 a schematic structural view of another embodiment of the buffer fixing member in

[0072] Of course, other methods can also be used. For example, please refer to Figure 4 and Figure 5 , it is possible to Figure 6 connect the two second sub-accommodation grooves 2402 in

[0073] Please continue to refer to Figure 4 , Figure 5 and Figure 6, in the second direction L2, a pick-and-place groove 248 is provided on each of the two opposite sides of the first sub-accommodating groove 2400. The pick-and-place groove 248 communicates with the first sub-accommodating groove 2400. The introduction of the pick-and-place groove 248 can reduce the difficulty of picking and placing the wound battery cell 1 and reduce the damage to the wound battery cell 1. Among them, the second direction L2 is perpendicular to the third direction L3 in which the first sub-accommodating groove 2400 points to the second sub-accommodating groove 2402, and in the third direction L3, the size of the first sub-accommodating groove 2400 is larger than the size of the pick-and-place groove 248; for example, in the third direction L3, the size of the first sub-accommodating groove 2400 is more than twice the size of the pick-and-place groove 248, etc. This design method can reduce the influence of the introduced pick-and-place groove 248 on the position of the wound battery cell to ensure the limiting effect of the accommodating groove 240 on the wound battery cell.

[0074] Please continue to refer to Figure 4 , the buffer fixing member 244 is provided with a first anti-fooling portion 241, and a second anti-fooling portion 243 is provided in the accommodating cavity 246. The first anti-fooling portion 241 and the second anti-fooling portion 243 cooperate with each other. Through the above design method of the first anti-fooling portion 241 and the second anti-fooling portion 243, the probability of placing the buffer fixing member 244 in the carrier 242 in the wrong orientation can be reduced to improve the detection efficiency.

[0075] Optionally, as Figure 4 shown, the buffer fixing member 244 includes a plurality of corners, and a notch is provided at one of the corners to form the first anti-fooling portion 241; the corresponding second anti-fooling portion 243 is a convex block matching the notch. Or, in other embodiments, a through hole is provided in a certain area of the buffer fixing member 244, and a convex block is provided at the position of the accommodating cavity 246 corresponding to the through hole.

[0076] In addition, Figure 4 , Figure 5 , Figure 6 the structure of the accommodating groove 240 in Figure 1 is designed corresponding to the square wound battery cell in Figure 3 . When the object to be detected is the Figure 7 cylindrical wound battery cell in Figure 7 , as Figure 4 shown, Figure 3 is a schematic structural view of another embodiment of the buffer fixing member in

[0077] . The structure of the accommodating groove 240 on the buffer fixing member 244 can be designed to adapt to the Figure 5 , Figure 6 and Figure 7 cylindrical wound battery cell in Figure 5 , Figure 6, Figure 7 The position marked as A1 in (), in this marking area, it is possible to set the detection of the cell model, digital number, etc., which is beneficial to quickly identify the buffer fixing member 244 corresponding to the current winding cell to be measured.

[0078] The following further describes the gap detection device provided by the present application from the perspective of the gap detection method. Please refer to Figure 1 , Figure 4 and Figure 8 , Figure 8 is a schematic flowchart of an implementation manner of the gap detection method of the present application. This gap detection method includes:

[0079] S101: Place the winding cell 1 in the receiving groove 240 of the carrying mechanism 24, and place the carrying mechanism 24 between the relatively arranged X-ray source 20 and the X-ray detector 22; wherein, in the height direction P1 of the winding cell 1, the winding cell 1 includes a wound body part 10 and a tab 12 connected to each other, and the height direction P1 of the winding cell 1 intersects with the first direction L1 in which the X-ray source 20 points to the X-ray detector 22.

[0080] Specifically, the winding cell 1 can be taken out from the production line and placed in the carrying mechanism 24; at this time, the winding cell 1 is a bare cell, that is, in an unpackaged state. Generally, a plurality of receiving grooves 240 are provided in the carrying mechanism 24. At this time, a winding cell 1 can be placed in each of all the receiving grooves 240, and each winding cell 1 can be detected separately.

[0081] S102: Make the X-ray source 20 irradiate the arc area 106 of the wound body part 10, and the X-ray detector 22 obtains an imaging image of the arc area 106.

[0082] Specifically, the X-rays emitted by the X-ray source 20 can penetrate the arc area 106 of the winding cell 1, and the X-ray detector 22 converts the received X-rays into electrical signals for imaging. Due to the different penetration capabilities of X-rays for different structures and materials in the sample, its internal structure can be collected by the X-ray detector 22 and presented on the computer.

[0083] S103: Obtain the gap value between two pole pieces in the arc area 106 based on the imaging image.

[0084] Specifically, please refer to Figure 9 , Figure 9 is Figure 8 a schematic flowchart of an implementation manner corresponding to step S103 in. The specific implementation process of the above step S103 includes:

[0085] S201: Preprocess the imaging image, and obtain the target area from the preprocessed imaging image.

[0086] Specifically, the preprocessing process may include four steps: multi-frame superposition and average denoising, region of interest (ROI) extraction, contrast enhancement, and filtering. Among them, multi-frame superposition and average denoising is to superpose and then average multiple imaging images continuously acquired by the X-ray detector 22, assign the average value to the corresponding new image, save the denoised new image, and release the memory, thereby reducing image noise and facilitating subsequent processing. ROI extraction is to crop the target area from the new image to crop out the target area to be detected, so as to improve the accuracy and processing time of image processing. Contrast enhancement is to extract the contrast of each part in the original image, highlight the positive and negative electrode tab lines in the target area, weaken the non-detection area, and make the image display effect clearer. Filtering is to scan each pixel in the image with a template, and replace the value of the template center pixel with the weighted average gray value of the pixels in the neighborhood determined by the template, so that the image is conducive to manual recognition. Specifically, as Figure 10 shown, Figure 10 is a schematic diagram of an implementation manner of the target area after step S201 in Figure 9 .

[0087] S202: Determine the position information of the positive electrode tab 100 and the negative electrode tab 102 from the target area based on the size information of the positive electrode tab 100 and the negative electrode tab 102.

[0088] Specifically, due to the difference in the materials of the positive electrode tab 100 and the negative electrode tab 102, the width of the negative electrode tab 102 is wider than that of the positive electrode tab 100. Therefore, the positions of each positive electrode tab 100 and negative electrode tab 102 can be determined from the target area based on the size information of the positive electrode tab 100 and the negative electrode tab 102.

[0089] S203: Obtain the gap value between adjacent positive electrode tabs 100 and negative electrode tabs 102 from the target area based on the position information of the positive electrode tab 100 and the negative electrode tab 102.

[0090] Specifically, as Figure 10As shown, after determining the positions of the respective positive electrode plates 100 and negative electrode plates 102, a line can be drawn 0.8 mm downward from the starting point of the negative electrode plate 102, and the center of the line is the brightest position of the negative electrode plate 102 (i.e., the center position of the electrode plate). Similarly, a line can be drawn 1 mm downward from the starting point of the positive electrode plate 100, and the center of the line is the brightest position of the positive electrode plate 100 (i.e., the center position of the electrode plate). In this embodiment, for the convenience of distinction, the drawing height of the positive electrode plate 100 is lower than that of the negative electrode plate 102. Of course, in other embodiments, other methods can also be used for distinction; for example, distinction can be made by setting different line types and / or line colors; among them, the line types include solid lines, dashed lines, etc. Subsequently, the gap value between the negative line and the positive line can be automatically measured, and the measured gap value is the distance from the center of the negative electrode plate 102 to the center of the positive electrode plate 100. After that, the measured gap value can be compared with the risk threshold. In response to the gap value being greater than or equal to the risk threshold, it is determined that the wound battery cell is unqualified; in response to the gap value being less than the risk threshold, it is determined that the wound battery cell is qualified. The inspectors can classify the qualified and unqualified wound battery cells and promptly feedback the inspection results to the production line.

[0091] To verify the accuracy of the gap detection method provided by the present application, three wound battery cells were randomly selected from the production line, and the gap detection method provided by the present application and the CT slice detection method in the prior art were used to test them. The relative error between the gap values obtained by the two test methods was compared. As shown in Table 1 below, Table 1 is a comparison table of the test results of the prior art and the present application.

[0092] Table 1: Comparison table of test results of the prior art and the present application

[0093]

[0094] Among them, the relative error = ∣(test value of the CT slice detection method - test value of the detection method of the present application)∣ / test value of the detection method of the present application * 100%. As shown in Table 1, the relative error between the gap values tested by the two methods is less than 20%, and the accuracy of the gap detection method provided by the present application is relatively high.

[0095] In a specific application scenario, the gap detection device provided by the present application employs a 150 KV microfocus X-ray source, a flat panel detector with a pixel size less than or equal to 100 microns and a magnification factor greater than or equal to 5 times, and a carrying mechanism with a load-bearing capacity exceeding 25 KG. Among them, the carrying mechanism includes a carrier and a buffer fixing member; the bottom plate of the carrier is made of a carbon fiber board, the side plates are made of stainless steel, and the height of the accommodation cavity formed by the side plates and the bottom plate in the carrying mechanism in the first direction is 10 mm. The buffer fixing member is made of black EVA foam, with a Shore hardness of 45 degrees and a height of 20 mm in the first direction. One of the corners of the buffer fixing member has a triangular notch to form a first anti-fooling part, and a second anti-fooling part in the form of a triangular protrusion matching the shape of the triangular notch is arranged in the corresponding accommodation cavity. When the buffer fixing member is arranged in the accommodation cavity, the first anti-fooling part and the second anti-fooling part abut against each other. In addition, a number is set at a position of the buffer fixing member adjacent to the first anti-fooling part, for example, the detection cell model, digital number, etc.

[0096] The above are only the embodiments of the present application, and do not limit the patent scope of the present application accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, are similarly included in the patent protection scope of the present application.

Claims

1. A clearance detection device, characterized in that, Used for winding a battery core, and in the height direction of the wound battery core, the wound battery core includes a wound body part and a pole ear connected to each other, and the gap detection device includes: An X-ray source and an X-ray detector arranged opposite to each other, and a supporting mechanism located between the X-ray source and the X-ray detector; The supporting mechanism includes at least one accommodating groove, the accommodating groove is used to accommodate the wound battery core, and the height direction of the wound battery core intersects with the first direction of the X-ray source pointing to the X-ray detector; the X-ray source is used to irradiate the arc-shaped area of the winding body, and the X-ray detector is used to obtain an imaging image of the irradiated arc-shaped area, so that the gap value between the two pole pieces in the arc-shaped area is obtained based on the imaging image; The bearing mechanism includes a bearing member and a buffer fixing member, the bearing member includes a receiving cavity on a side facing the X-ray source or the X-ray detector, the buffer fixing member is located in the receiving cavity, and the receiving groove is provided on the buffer fixing member; The accommodating groove includes a first sub-accommodating groove and a second sub-accommodating groove which are interconnected, the first sub-accommodating groove is used to accommodate the winding body part, and the second sub-accommodating groove is used to accommodate the pole ear; wherein, there is a preset interval between the winding body part and the inner wall of the first sub-accommodating groove, and between the pole ear and the inner wall of the second sub-accommodating groove.

2. The gap detection device according to claim 1, characterized in that: In the first direction, the accommodating groove passes through the buffer fixing member; And / or, the Shore hardness of the buffer fixing member is greater than or equal to 40 degrees and less than or equal to 50 degrees; And / or, the buffer fixing element includes foam.

3. The gap detection device according to claim 1, characterized in that: There are two pole lugs, which are arranged on the same side of the winding body; and the second sub-accommodating groove is used to accommodate the two pole lugs.

4. The gap detection device according to claim 1, characterized in that: In the second direction, two sides of the first sub-receiving groove that are opposite to each other are respectively provided with a picking and placing groove connected thereto; wherein, the second direction is perpendicular to the third direction from the first sub-receiving groove to the second sub-receiving groove, and the size of the receiving groove in the third direction is larger than the size of the picking and placing groove.

5. The gap detection device according to claim 1, characterized in that: The buffer fixing piece is provided with a first fool-proofing portion, and the accommodating cavity is provided with a second fool-proofing portion, and the first fool-proofing portion and the second fool-proofing portion cooperate with each other.

6. The gap detection device according to claim 1, characterized in that: The bearing member comprises a bottom plate and side plates connected to each other, and the side plates are arranged around the bottom plate to form the accommodating cavity; Wherein, the material of the bottom plate includes carbon fiber, and the material of the side plate includes metal.

7. The gap detection device according to claim 6, characterized in that: The carrier also includes two handles arranged opposite to each other and located on the outer surface of the side plate at a side away from the accommodating cavity.

8. A gap detection method, characterized in that, Using the gap detection device according to any one of claims 1-7, the gap detection method includes: Placing the wound battery cell in the accommodating groove of the carrying mechanism, and arranging the carrying mechanism between the relatively arranged X-ray source and X-ray detector; wherein, in the height direction of the wound battery cell, the wound battery cell includes a wound body part and a tab connected to each other, and the height direction of the wound battery cell intersects with the first direction in which the X-ray source points to the X-ray detector; Irradiating the arc-shaped area of the wound body part with the X-ray source, and the X-ray detector obtains an imaging image of the arc-shaped area; Obtaining the gap value between two electrode plates in the arc-shaped area based on the imaging image.

9. The gap detection method according to claim 8, characterized in that, The wound body part includes alternately arranged positive electrode plates and negative electrode plates; the step of obtaining the gap value between two electrode plates in the wound body part in the arc-shaped area based on the imaging image includes: Performing preprocessing on the imaging image, and obtaining a target area from the preprocessed imaging image; Determining the position information of the positive electrode plate and the negative electrode plate from the target area based on the size information of the positive electrode plate and the negative electrode plate; Obtaining the gap value between the adjacent positive electrode plate and negative electrode plate from the target area based on the position information of the positive electrode plate and the negative electrode plate.

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