Battery piece detection system and method
Through the vertical cavity surface emission laser chip forming light source array module and light shaping technology, combined with the image acquisition unit, the problems of hysteresis and low production efficiency of existing cell detection methods are solved, and efficient, accurate and reliable cell chips are achieved Test.
Patent Information
- Application Number
- CN202411661843.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2024-12-27
AI Technical Summary
Existing cell defect detection methods such as EL and PL detection methods have problems of hysteresis and low production efficiency, especially the use of edge emission lasers or fiber lasers can easily affect product quality and production efficiency.
The vertical cavity surface emission laser chip is used to form a light source array module, and combine the light shaping unit and the image acquisition unit to form a cell detection system. A large area of light beam is emitted through the laser unit, and the light shaping is used to irradiate the cell with a uniform beam. The image acquisition unit acquires images Perform testing.
It realizes high efficiency, contactless, low power density and high reliability of cell detection, avoids the occurrence of secondary defects, simplifies the optical system structure, and improves the accuracy and production efficiency of detection.
Smart Images
Figure CN119198557A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of battery cell detection, and in particular to a battery cell detection system and method. Background Art
[0002] Existing cell defect detection generally uses EL (Electroluminescence) or PL (Photoluminescence) detection methods to distinguish defects such as hidden cracks, virtual prints, black spots, belt marks, and diffusion anomalies.
[0003] However, the EL test method requires final inspection of the battery after it is finished, and then reversely investigates the possible manufacturing or parameter problems of each process, which has a large lag and causes waste of materials and manpower. The PL detection method mostly uses edge-emitting lasers or fiber lasers, which can easily affect product quality and production efficiency. Summary of the invention
[0004] Based on this, it is necessary to provide a battery cell detection system and method to address the above technical issues.
[0005] In a first aspect, the present application provides a battery cell detection method. The method comprises:
[0006] A laser unit, wherein the laser unit comprises a plurality of vertical cavity surface emitting laser chips, a heat sink, and a substrate, wherein the substrate is mounted on the heat sink, and the vertical cavity surface emitting laser chips are mounted on the substrate to form an array module;
[0007] A light shaping unit, including one or more of a light homogenizer, a light guide tube, and a lens group, wherein the light shaping unit is disposed between the laser unit and the battery cell;
[0008] An image acquisition unit is used to acquire an image of the battery sheet generated under the irradiation of the laser unit. The image acquisition unit and the laser unit are independently arranged, or the image acquisition unit and the laser unit are integrated.
[0009] In one of the embodiments, the image acquisition unit includes a light receiving chip and a camera.
[0010] In one embodiment, the image acquisition unit and the laser unit are integrated into one another and include:
[0011] The light-receiving chip and the vertical-cavity surface-emitting laser chip are mounted on the heat sink together, and the light-receiving chip and the vertical-cavity surface-emitting laser chip are arranged in a common optical path, and the common optical path includes the same path through which the light emitted by the vertical-cavity surface-emitting laser chip and the light received by the light-receiving chip pass.
[0012] In one embodiment, the image acquisition unit and the laser unit are independently arranged to include:
[0013] The camera and the laser unit are independently arranged, and the distance or angle between the laser unit and the camera is adjusted based on preset detection conditions.
[0014] In one embodiment, one end of the light guide is the incident end, the other end of the light guide is the exit end, a reflective surface is formed on the inner side of the light guide, and the inclination angle of the side wall of the light guide is smaller than the divergence angle of the light source.
[0015] In one embodiment, the incident end and the output end of the light guide are both rectangular, and the aperture size of the incident end is smaller than the aperture size of the output end.
[0016] In one of the embodiments, the light shaping unit comprises a light pipe array, the light pipe array comprises a plurality of light pipes, and the light pipes are arranged in a one-to-one correspondence with the vertical cavity surface emitting laser chips.
[0017] In one of the embodiments, the light shaping unit comprises a light pipe array, the light pipe array comprises a plurality of light pipes, and one light pipe is arranged corresponding to a plurality of vertical cavity surface emitting laser chips.
[0018] In one embodiment, the light homogenizer includes one or more of a scattering sheet, a microlens array, a diffractive optical element, and a superlens;
[0019] The lens group includes an imaging lens group and a non-imaging lens group.
[0020] In a second aspect, the present application further provides a battery cell detection method, which is used in any of the detection systems described above, and the method comprises:
[0021] The laser unit emits a large-area light beam;
[0022] The light shaping unit shapes the large-area light beam emitted by the laser unit into a uniform light beam, and irradiates the light beam onto the battery cell to be inspected;
[0023] The image acquisition unit acquires the image collected from the battery cell to be inspected;
[0024] The quality of the battery cell is detected based on the collected image.
[0025] The above-mentioned battery cell detection system has at least the following beneficial effects:
[0026] The embodiment scheme provided by the present disclosure can form a light source array module by connecting vertical cavity surface emitting laser chips in series and parallel to form a large-area light source, use a light shaping unit to control the shape, size and uniformity of the light source, and irradiate it onto the battery cell to be inspected, and the image acquisition unit obtains the image generated by the battery cell under the irradiation of the laser unit. The image acquisition unit can be set independently from the laser unit, or it can be integrated with the laser unit to form a battery cell detection system. The vertical cavity surface emitting laser chips can be expanded horizontally to form a large-area array, without the need for a complex optical system, with low power density, simple structure and high reliability, and no contact with the battery cell, so secondary defects are not easily generated.
[0027] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0029] Figure 1 A conventional battery cell detection system in one embodiment;
[0030] Figure 2 is a schematic diagram of a battery cell detection system in one embodiment;
[0031] Figure 3 is a schematic diagram of a laser unit in one embodiment;
[0032] Figure 4 A schematic diagram of an integrated arrangement of an image acquisition unit and a laser unit in one embodiment;
[0033] Figure 5 A schematic diagram of an embodiment in which the image acquisition unit and the laser unit are independently arranged;
[0034] Figure 6 is a schematic diagram of a light guide tube in one embodiment;
[0035] Figure 7 A schematic diagram of using a light homogenizer to uniformly distribute light in one embodiment;
[0036] Figure 8 A schematic diagram of using a lens group to uniformly light in one embodiment;
[0037] Fig. 9 Schematic diagram of a battery cell detection method in one embodiment. DETAILED DESCRIPTION
[0038] In order to enable ordinary persons in the art to better understand the technical solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings.
[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are only examples of devices and methods consistent with some aspects of the present disclosure as detailed in the attached claims. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, product or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, product or device. In the absence of more restrictions, it is not excluded that there are other identical or equivalent elements in the process, method, product or device including the elements. For example, if the words first, second, etc. are used to represent the name, they do not represent any specific order.
[0040] Figure 1 A conventional cell inspection system in an embodiment may include a cell 100, a camera 102, and a light source 104. The camera 102 is usually installed above the cell 100 to ensure that a complete cell image can be captured from above. The light source 104 may be installed in a circular position around the cell 104 to ensure that the light evenly covers the entire cell surface.
[0041] Figure 2 Schematic diagram of a battery cell detection system in one embodiment. The present disclosure provides a battery cell detection system 200, the system 200 comprising:
[0042] Laser unit 202, Figure 3 Schematic diagram of a laser unit in an embodiment, the laser unit 202 includes a plurality of vertical cavity surface emitting laser chips 302, a heat sink 306, and a substrate 304, the substrate 304 is mounted on the heat sink 306, and the vertical cavity surface emitting laser chips 302 are mounted on the substrate 304 to form an array module.
[0043] Vertical-Cavity Surface-Emitting Laser (VCSEL) is a laser that emits laser light perpendicular to the substrate surface. The emission direction of VCSEL is perpendicular to the wafer surface, rather than along the edge of the wafer, so that VCSEL can be easily integrated on the circuit board and can be easily arranged into a larger area light source array. In addition, the wavelength and threshold of VCSEL are relatively insensitive to temperature changes; the packaging is simple, and a two-dimensional laser array can be formed; the expected working life is long.
[0044] The substrate is the basic support structure of the entire laser unit, providing electrical connection and support. It can be made of ceramic material or metal substrate. In this embodiment, a ceramic substrate can be selected. The ceramic substrate is an insulating material with good thermal conductivity. The heat sink is mainly used for heat dissipation to ensure that the VCSEL chip will not be damaged due to overheating during operation. It is usually made of materials with good thermal conductivity, such as copper, aluminum, etc. The substrate is installed on the heat sink, and multiple VCSEL chips are connected in series and parallel and installed on the substrate to form an array module, forming a large-area light source.
[0045] The light shaping unit 204 includes one or more of a light homogenizer, a light pipe, and a lens group. The light shaping unit is disposed between the laser unit 202 and the battery cell.
[0046] The light shaping unit is used to collimate the light beam emitted by the laser unit to ensure that the light beam has good directionality and uniformity before reaching the battery cell. The light shaping unit may include one or more components of a homogenizer, a light pipe, and a lens group. The homogenizer can convert an uneven light beam into a uniform beam distribution to improve the quality of the light beam, and may include a scattering sheet or a microlens array (DOE). The light pipe can be used to guide the light beam, reduce the loss of the light beam during transmission, and maintain the directionality of the light beam. The lens group can be used to adjust the divergence angle of the light beam to achieve the collimation of the light beam, and may include one or more lenses. By adjusting the position and combination of the lenses, the focusing of the light beam can be achieved.
[0047] The image acquisition unit 206 is used to acquire the image generated by the cell under the irradiation of the laser unit. The image acquisition unit and the laser unit are independently provided, or the image acquisition unit and the laser unit are integrated.
[0048] Image acquisition is used to obtain the image generated by the cell under the irradiation of the laser unit. The image can be used to detect defects on the cell, measure the size of the cell, or evaluate the quality of the cell. The image acquisition unit can be integrated with the laser unit, sharing the same housing or installed on a substrate, which reduces the footprint of the equipment and makes the entire system more compact. The image acquisition unit can be installed in different positions from the laser unit, and the position and angle of the image acquisition unit can be adjusted according to actual needs to obtain the best image quality.
[0049] In the above-mentioned battery cell detection system, a light source array module can be formed by connecting vertical cavity surface emitting laser chips in series and parallel to form a large-area light source. The shape, size and uniformity of the light source can be controlled by a light shaping unit, and the light source is irradiated onto the battery cell to be detected. The image acquisition unit obtains the image generated by the battery cell under the irradiation of the laser unit. The image acquisition unit can be set independently from the laser unit, or it can be integrated with the laser unit to form a battery cell detection system. The vertical cavity surface emitting laser chip can be expanded laterally to form a large-area array, without the need for a complex optical system, with low power density, simple structure and high reliability, and no contact with the battery cell, so secondary defects are not easily generated.
[0050] In some embodiments of the present disclosure, the image acquisition unit includes a light receiving chip and a camera.
[0051] The light receiving chip can convert the received light signal into an electrical signal, which can include CCD (Charge-Coupled Device) sensor and CMOS (Complementary Metal-Oxide-Semiconductor) sensor. The battery cell can also be directly photographed by a camera to obtain the image to be tested.
[0052] In some embodiments of the present disclosure, the image acquisition unit and the laser unit are integrated into one another and include:
[0053] The light-receiving chip and the vertical-cavity surface-emitting laser chip are mounted on the heat sink together, and the light-receiving chip and the vertical-cavity surface-emitting laser chip are arranged in a common optical path, and the common optical path includes the same path through which the light emitted by the vertical-cavity surface-emitting laser chip and the light received by the light-receiving chip pass.
[0054] Figure 4The figure is a schematic diagram of an integrated arrangement of an image acquisition unit and a laser unit in an embodiment. The light receiving chip and the vertical cavity surface emitting laser chip are installed on the same heat sink, and the light receiving chip and the vertical cavity surface emitting laser chip are arranged in a common optical path, which is the same path through which the light emitted by the vertical cavity surface emitting laser chip and the light received by the light receiving chip pass, which helps to simplify the system structure and reduce the number of optical elements in the optical path.
[0055] In some embodiments of the present disclosure, the image acquisition unit and the laser unit are independently arranged to include:
[0056] The camera and the laser unit are independently arranged, and the distance or angle between the laser unit and the camera is adjusted based on preset detection conditions.
[0057] Figure 5 Schematic diagram of an independent arrangement of the image acquisition unit and the laser unit in one embodiment. The camera can be independently arranged from the laser unit, and the laser unit and the camera can be installed in the best position to meet specific detection requirements. Independent arrangement can facilitate adjustment of the distance or angle between the laser unit and the camera to optimize the lighting and imaging effects.
[0058] In some embodiments of the present disclosure, one end of the light guide is the incident end, the other end of the light guide is the exit end, a reflective surface is formed on the inner side of the light guide, and the inclination angle of the side wall of the light guide is smaller than the divergence angle of the light source.
[0059] Figure 6 It is a schematic diagram of a light guide in an embodiment. The incident end is the end of the light guide that receives the light beam emitted by the laser unit. The incident end can be designed to be flat or slightly inclined to ensure that the light beam can smoothly enter the interior of the light guide. The exit end is the end of the light guide that transmits the light beam to the surface of the battery cell. It can be designed to be flat or slightly inclined to ensure that the light beam can be evenly irradiated on the surface of the battery cell. The inclination angle of the side wall of the light guide is smaller than the divergence angle of the light source. The inner wall of the side wall of the light guide is a reflective surface, which is used to guide the light beam to propagate inside the light guide, reflect the large-angle light emitted by the light source, and deflect the light to the center area of the light spot, thereby obtaining a uniform square light spot and reducing the loss of the light beam. The reflective surface can be made of a material with high reflectivity, such as a silver-plated or aluminum-plated surface.
[0060] In some embodiments of the present disclosure, both the incident end and the output end of the light guide are rectangular, and the aperture size of the incident end is smaller than the aperture size of the output end.
[0061] The aperture size of the incident end is small and close to the light source, which can better focus the light beam and reduce the loss of the light beam when entering the light guide. The aperture size of the output end is large, which can make the light beam evenly cover the surface of the battery cell and improve the accuracy of detection.
[0062] In some embodiments of the present disclosure, the light shaping unit includes a light pipe array, the light pipe array includes a plurality of light pipes, and the light pipes are arranged in a one-to-one correspondence with the vertical cavity surface emitting laser chips.
[0063] In some embodiments, a large light pipe can be used to homogenize the light source, and all the light sources emitted by the laser unit are incident on the incident end of the light pipe, and the light is emitted to the battery to be detected through the output end. In some embodiments, multiple light pipe arrays can also be used, and the array module includes multiple vertical cavity surface emitting laser chips. Each vertical cavity surface emitting laser chip can correspond to a light pipe array. Using multiple light pipes can better control the uniformity of the light spot, and each light pipe can independently adjust the shape and intensity of its output light spot.
[0064] In some embodiments of the present disclosure, the light shaping unit includes a light pipe array, the light pipe array includes a plurality of light pipes, and one light pipe is arranged corresponding to a plurality of vertical cavity surface emitting laser chips.
[0065] A light guide can be set corresponding to multiple vertical cavity surface emitting laser chips. For example, the current module array includes 16 vertical cavity surface emitting laser chips. According to the light quality requirements, 2, 4, or 8 vertical cavity surface emitting laser chips can be divided into a group. Each group of chips corresponds to a light guide, and each light guide is responsible for homogenizing a part of the light source, which can better control the shape and uniformity of the light spot.
[0066] In some embodiments of the present disclosure, the light homogenizer includes one or more of a scattering sheet, a microlens array, a diffractive optical element, and a superlens;
[0067] The lens group includes an imaging lens group and a non-imaging lens group.
[0068] The light homogenizer includes one or more of a frosted glass diffuser, a diffuser, a microlens array (DOE), and a superlens. A frosted glass diffuser is a piece of glass with a rough surface that homogenizes the light spot by scattering light, and is used to convert a point light source or an uneven light source into a more uniform light spot. The diffuser is a full glass material made by molding or photolithography. Microstructures are manufactured on the glass surface by photolithography technology to change the propagation direction of light and achieve a scattering effect. The superlens is a full glass material made by photolithography, which can achieve sub-wavelength scale focusing and imaging. It can be used with a lens and a light homogenizer, or it can be used alone to obtain a uniform light spot. The lens can be used to focus or diverge light, and a more uniform light spot can be obtained when used in combination with a light homogenizer.
[0069] Figure 7Schematic diagram of using a light homogenizer to uniformly distribute light in an embodiment, wherein 7-1 uses a light homogenizer alone, 7-2 uses a lens in combination with a light homogenizer, 7-3 uses a micro-column lens array with the busbars perpendicular to each other, 7-4 and 7-5 are combinations of a lens in combination with a diffuser, f represents the focal length of the lens, and d represents the distance from the diffuser to the object to be detected.
[0070] Figure 8 Figure 8 is a schematic diagram of using a lens group to make light uniform in an embodiment. The lens group includes at least one lens, all of which are glass lenses. 8-1 is an imaging lens group. The surface of the array module passes through the imaging lens group so that the spot size reaches 300m~500mm at a working distance of 300-600mm. The uniformity of the power spot exceeds 80%. At the working distance, the maximum light power density of the spot is 1W / cm2, and the typical value is about 0.1W / cm2. 8-2 is a non-imaging lens group. The imaging system refers to a lens group used to form a clear image, usually used in imaging applications such as photography or microscopy. The non-imaging lens group refers to a lens group mainly used to change the shape, size or uniformity of the light source, rather than to form a clear image.
[0071] In some embodiments of the present disclosure, a battery cell detection method is provided. Fig. 9 Schematic diagram of a battery cell detection method in an embodiment, which is used in any of the detection systems described above, and the method includes:
[0072] S902: The laser unit emits a large-area light beam;
[0073] S904: The light shaping unit shapes the large-area light beam emitted by the laser unit into a uniform light beam, and irradiates the light beam onto the battery cell to be inspected;
[0074] S906: The image acquisition unit acquires the image collected from the battery cell to be inspected;
[0075] S908: Detect the quality of the battery cell based on the collected image.
[0076] The laser unit emits a large area beam, which covers as much of the cell surface as possible to ensure uniform illumination of the entire detection area. The light beam emitted by the laser unit is shaped into a uniform beam through a light shaping unit to ensure that the light beam irradiated on the cell has good uniformity and directionality. For example, a light scattering sheet, a microlens array, a superlens and other light homogenizing mirror components, as well as an imaging lens group or a non-imaging lens group, are used to shape the light beam. The shaped light beam is irradiated onto the cell to be inspected to ensure that the cell surface is irradiated with a uniform light beam so as to obtain a high-quality image.
[0077] When the laser is irradiated onto the cell to be tested, the electrons in the cell to be tested absorb the photon energy and transition from the ground state to the excited state. The excited electrons release energy when returning to the ground state, generating fluorescence. For solar cells, fluorescence usually peaks in the infrared band near 1150nm. If there are defects in the cell to be tested, the minority carrier concentration in these areas will decrease, resulting in a decrease in fluorescence intensity. By capturing these fluorescence images with a highly sensitive and high-resolution camera, it can be observed that the defective areas appear as dark dots, lines or areas, and the quality of the cell to be tested can be obtained.
[0078] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.
[0079] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0080] The above-described embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the attached claims.
Claims
1. A battery cell detection system, characterized in that: The system comprises: A laser unit, wherein the laser unit comprises a plurality of vertical cavity surface emitting laser chips, a heat sink, and a substrate, wherein the substrate is mounted on the heat sink, and the vertical cavity surface emitting laser chips are mounted on the substrate to form an array module; A light shaping unit, including one or more of a light homogenizer, a light guide tube, and a lens group, wherein the light shaping unit is disposed between the laser unit and the battery cell; An image acquisition unit is used to acquire an image of the battery sheet generated under the irradiation of the laser unit. The image acquisition unit and the laser unit are independently arranged, or the image acquisition unit and the laser unit are integrated.
2. The system according to claim 1, characterized in that The image acquisition unit includes a light-collecting chip and a camera.
3. The system according to claim 2, characterized in that The image acquisition unit and the laser unit are integrated into one another and include: The light-receiving chip and the vertical-cavity surface-emitting laser chip are mounted on the heat sink together, and the light-receiving chip and the vertical-cavity surface-emitting laser chip are arranged in a common optical path, and the common optical path includes the same path through which the light emitted by the vertical-cavity surface-emitting laser chip and the light received by the light-receiving chip pass.
4. The system according to claim 2, characterized in that The image acquisition unit and the laser unit are independently arranged to include: The camera and the laser unit are independently arranged, and the distance or angle between the laser unit and the camera is adjusted based on preset detection conditions.
5. The system according to claim 1, characterized in that One end of the light guide is an incident end, and the other end of the light guide is an exit end. A reflecting surface is formed inside the light guide, and an inclination angle of a side wall of the light guide is smaller than a divergence angle of the light source.
6. The system according to claim 5, characterized in that The incident end and the output end of the light guide are both rectangular, and the aperture size of the incident end is smaller than the aperture size of the output end.
7. The system according to claim 5, characterized in that The light shaping unit comprises a light pipe array, the light pipe array comprises a plurality of light pipes, and the light pipes are arranged in a one-to-one correspondence with the vertical cavity surface emitting laser chips.
8. The system according to claim 5, characterized in that The light shaping unit comprises a light pipe array, the light pipe array comprises a plurality of light pipes, and one light pipe is arranged corresponding to a plurality of vertical cavity surface emitting laser chips.
9. The system according to claim 1, characterized in that The light homogenizer includes one or more of a scattering sheet, a microlens array, a diffraction optical element, and a superlens; The lens group includes an imaging lens group and a non-imaging lens group.
10. A battery cell detection method, used in the detection system according to any one of claims 1 to 9, characterized in that: The method comprises: The laser unit emits a large-area light beam; The light shaping unit shapes the large-area light beam emitted by the laser unit into a uniform light beam, and irradiates the light beam onto the battery cell to be inspected; The image acquisition unit acquires the image collected from the battery cell to be inspected; The quality of the battery cell is detected based on the collected image.