Welding quality detection method and device, computer-readable storage medium, and product

Abstract

The present application relates to the technical field of batteries, and provides a welding quality detection method, a welding quality detection system, a welding quality detection device, a computer-readable storage medium, and a computer program product. The welding quality detection method comprises: acquiring vibration data, at a resonance frequency, of a welding sample detected by a vibration detector, wherein the resonance frequency is an excitation frequency for driving a welding sample to vibrate by means of the vibration generator; determining at least one vibration parameter of the welding sample on the basis of the vibration data; and in response to at least one of the at least one vibration parameter satisfying a criterion associated with a corresponding threshold, determining that a welding defect is present in the welding sample. Defect detection is carried out by directly extracting a vibration parameter of a welding sample, thereby achieving the characteristics of high detection precision and high detection efficiency.

Description

Welding quality detection method, device, computer-readable storage medium and product

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202311027006.3, filed on August 15, 2023, entitled “Welding quality detection method, device, computer-readable storage medium and product”, which is incorporated into this application in its entirety by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a welding quality detection method, a welding quality detection system, a welding quality detection device, a computer-readable storage medium, and a computer program product. 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, the welding quality between the various components of the battery will affect the reliability of the produced battery. If batteries with poor welding quality flow into the market, it may cause product safety risks.

[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 purpose of the present application is to provide a welding quality detection method and device to improve the detection rate of welding problems in the battery manufacturing process to a certain extent.

[0008] An embodiment of the first aspect of the present application provides a welding quality detection method, which includes: obtaining vibration data of a welding sample detected by a vibration detector at a resonant frequency, wherein the resonant frequency is an excitation frequency at which the welding sample is driven to vibrate via a vibration generator; determining at least one vibration parameter of the welding sample based on the vibration data; and determining that a welding defect exists in the welding sample in response to at least one of the at least one vibration parameter satisfying a standard associated with a corresponding threshold.

[0009] The technical solution of the embodiments of this application directly extracts the vibration parameters of the weld sample at the resonant frequency for defect detection, which features high detection accuracy, convenience, and efficiency. If the weld can maintain stable vibration parameters at the resonant frequency, it indicates good weld quality. Conversely, if the vibration parameters meet the standards associated with the corresponding thresholds at the resonant frequency, it indicates that the weld may have problems, thereby improving the detection rate of weld defects to a certain extent.

[0010] In some embodiments, the threshold value of at least one vibration parameter is obtained by statistically analyzing the values ​​of at least one vibration parameter at the resonant frequency of at least one good weld. In vibration testing, good welds are used to set the inspection standard. The purpose of setting the threshold value of each vibration parameter is to determine whether the weld sample is qualified based on this threshold value in subsequent tests.

[0011] In some embodiments, the resonant frequency is determined by measuring the maximum vibration velocity of at least one good weld. Using the resonant frequency as the excitation frequency enables the sample vibration signal to reach a peak value, helping to reduce the impact of noise during the measurement process on the measurement results, thereby improving measurement accuracy.

[0012] In some embodiments, at least one good weld is obtained by the following steps: obtaining shear force test results for each of M weld samples out of N weld samples, wherein the N weld samples are welded under the same process conditions, N and M are integers greater than 1, and M<N; and in response to the shear force test results for each of the M weld samples satisfying a good quality evaluation criterion, determining the remaining NM weld samples out of the N weld samples as at least one good weld. Due to the high consistency of battery cell manufacturing, the welding variability between weld samples from the same batch welded under the same process conditions is relatively small. Therefore, by selecting a portion of weld samples from the same batch welded under the same process conditions for shear force testing, if the shear force test results for each weld sample satisfy the good quality evaluation criterion, the weld samples in the batch are considered to meet the good quality evaluation criterion, and the remaining NM weld samples that have not undergone shear force testing can be determined as good welds. In some embodiments, for each of the M weld samples, the shear force test result includes the weld mark residual rate of the weld sample under shear force, wherein the weld mark residual rate is the ratio of the number of residual weld points of the weld sample after stretching under shear force to the total number of weld points of the weld sample. By evaluating the welding quality of the battery tab and the adapter based on the shear force and the weld mark residual rate, good welding products can be obtained, which can better evaluate the welding quality of the battery tab and the adapter.

[0013] In some embodiments, for each of the M weld samples, the quality evaluation indicators include: 100 Newtons (N) ≤ τ ≤ 800 N, where τ is the shear force to which the weld is subjected; and 0.5 ≤ R ≤ 1, where R is the weld mark residual rate of the weld. The shear force and weld mark residual rate can be used to characterize the shear strength and weld quality of the weld structure, and can be used to assess the actual performance of the weld quality, thereby better evaluating the weld quality between the battery tab and the adapter.

[0014] In some embodiments, the at least one vibration parameter includes at least one of a characteristic parameter characterizing a vibration shape of the welding sample, a vibration velocity of the welding sample, and a soldering rate of a weld print area of ​​the welding sample, wherein the soldering rate is a ratio of an area of ​​a soldered region within the weld print area to an area of ​​the weld print area.

[0015] By characterizing whether at least one of the characteristic parameters of the vibration shape of the welding sample, the vibration speed of the welding sample, and the soldering rate of the weld mark area of ​​the welding sample meets the standards associated with the corresponding thresholds, the detection accuracy and efficiency of the welding joint can be improved to a certain extent.

[0016] In some embodiments, the characteristic parameter of the vibration shape includes the aspect ratio of the vibration shape. By monitoring the change in the aspect ratio of the vibration shape, it is possible to directly determine whether a crack is found in the weld joint and the severity of the crack, thereby improving detection efficiency.

[0017] In some embodiments, the corresponding thresholds include a first threshold for the aspect ratio of the vibration shape, and the criterion associated with the first threshold is that the aspect ratio of the vibration shape is less than the first threshold. By determining whether the aspect ratio of the vibration shape of the weld sample is less than the first threshold, it is possible to quickly determine whether cracks have occurred in the weld joint of the weld sample, thereby improving the accuracy and efficiency of weld joint inspection to a certain extent.

[0018] In some embodiments, the corresponding threshold value includes a second threshold value for the vibration velocity of the welding sample, and the criterion associated with the second threshold value is that the vibration velocity of the welding sample is greater than the second threshold value. By characterizing whether the vibration velocity of the welding sample is greater than the second threshold value, it is possible to quickly determine whether a weld joint of the welding sample has a cold weld, thereby improving the accuracy and efficiency of welding joint inspection to a certain extent.

[0019] In some embodiments, the corresponding thresholds include a third threshold for the soldering rate of the weld mark area, and the criterion associated with the third threshold is that the soldering rate of the weld mark area is less than the third threshold. By determining whether the soldering rate of the weld sample is less than the third threshold, it is possible to quickly determine whether the connection strength of the weld joint of the weld sample meets a preset standard, thereby improving the accuracy and efficiency of weld joint inspection to a certain extent.

[0020] In some embodiments, while the welding sample is vibrating at the resonant frequency, the welding sample is placed on a vibration isolation platform, which can isolate the interference of environmental vibrations and improve the stability and accuracy of the measurement.

[0021] In some embodiments, the vibration generator includes an ultrasonic transducer, which can improve measurement stability and detection efficiency.

[0022] In some embodiments, the welding sample includes a battery tab-to-adapter tab weld joint. By acquiring vibration data of the battery tab-to-adapter tab weld joint, it is possible to detect the welding quality of a specified portion of the battery.

[0023] In some embodiments, the resonant frequency of the tab-to-adapter tab weld joint is obtained by: driving a good tab-to-adapter tab weld joint to vibrate using a vibration generator, wherein the excitation frequency of the vibration generator gradually changes; detecting the vibration velocity of the good tab-to-adapter tab weld joint at the gradually changing excitation frequency using a vibration detector; and determining the excitation frequency corresponding to the maximum vibration velocity of the good tab-to-adapter tab weld joint as the resonant frequency of the tab-to-adapter tab weld joint. By gradually changing the excitation frequency of the vibration generator, it is easy to determine at which excitation frequency the vibration velocity of the good tab-to-adapter tab weld joint is the maximum, thereby obtaining the resonant frequency of the tab-to-adapter tab weld joint.

[0024] In some embodiments, the excitation frequency of the vibration generator is gradually varied in the following manner: the excitation frequency of the vibration generator is increased in frequency steps from a first frequency to a second frequency, or decreased in frequency steps from the second frequency to the first frequency, wherein the second frequency is greater than the first frequency. By gradually increasing the excitation frequency in frequency steps, the response of a good tab-to-adapter weld joint at different excitation frequencies can be observed, overexcitation can be reduced, and the vibration velocity of the good tab-to-adapter weld joint can be easily determined at which excitation frequency the vibration velocity of the good tab-to-adapter weld joint is the highest, thereby obtaining the resonant frequency of the tab-to-adapter weld joint.

[0025] In some embodiments, the first frequency is 20 kilohertz (kHz), the second frequency is 800 kHz, and the frequency step is 1 to 5 kHz. By setting a suitable frequency step, a more accurate resonant frequency can be found, thereby improving detection accuracy.

[0026] In some embodiments, an embodiment of the second aspect of the present application provides a welding quality detection system, comprising: a vibration generator, a vibration detector, a memory and a processor, wherein the memory stores instructions; and a processor, the processor being configured to execute instructions to perform operations, the operations comprising: driving the welding sample to vibrate at a resonant frequency via the vibration generator; obtaining vibration data of the welding sample at the resonant frequency detected by the vibration detector; determining at least one vibration parameter of the welding sample based on the vibration data; and determining that a welding defect exists in the welding sample in response to at least one of the at least one vibration parameter meeting a standard associated with a corresponding threshold.

[0027] By providing a welding quality inspection system, the vibration parameters of the welding sample are directly extracted for defect detection, which has the characteristics of high detection accuracy, convenience and efficiency.

[0028] In some embodiments, a welding quality inspection system further includes a vibration isolation platform configured to support the welding sample while the welding sample is vibrating at a resonant frequency. The vibration isolation platform can isolate the welding sample from interference from ambient vibrations, thereby improving measurement stability and accuracy.

[0029] In some embodiments, the vibration waves generated by the vibration generator are transmitted to the vibration isolation platform along a first direction, where the first direction forms an acute angle θ with the surface of the isolation platform supporting the weld sample. This acute angle of incidence can reduce measurement errors and improve detection accuracy. Furthermore, this acute angle of incidence allows for a longer vibration path, enabling more accurate measurement results.

[0030] In some embodiments, the acute angle θ satisfies the following conditions: 40 degrees (°) ≤ θ ≤ 60 degrees. Applying an angle of 40°-60° to the weld sample can reduce measurement errors and improve detection accuracy. Furthermore, applying an angle of 40°-60° can extend the vibration path, enabling more accurate measurement results.

[0031] In some embodiments, the vertical distance H between the vibration detector and the welding sample satisfies: 20 mm ≤ H ≤ 50 mm. By adjusting the vertical distance between the vibration detector and the welding sample, the attenuation of the detection signal can be reduced, and the interference of environmental noise can be reduced, thereby improving the detection accuracy.

[0032] In some embodiments, the vibration generator includes an ultrasonic transducer, which generates ultrasonic waves in response to an excitation signal and projects the ultrasonic waves onto the weld sample, driving the weld sample to vibrate at a resonant frequency. The use of an ultrasonic transducer can improve measurement stability and detection efficiency to a certain extent.

[0033] In some embodiments, a welding quality inspection system further includes a signal generator for generating a voltage signal; and a power amplifier for amplifying the voltage signal to provide an excitation signal.

[0034] In some embodiments, the welding sample includes a battery tab-to-adapter tab weld joint. By acquiring vibration data of the battery tab-to-adapter tab weld joint, it is possible to detect the welding quality of a specified portion of the battery.

[0035] An embodiment of the third aspect of the present application provides a welding quality detection device, which includes a first module, a second module and a third module. The first module is used to obtain vibration data of a welding sample detected by a vibration detector at a resonant frequency, wherein the resonant frequency is an excitation frequency at which the welding sample is driven to vibrate via a vibration generator; the second module is used to determine at least one vibration parameter of the welding sample based on the vibration data; and the third module is used to determine that a welding defect exists in the welding sample in response to at least one of the at least one vibration parameters meeting a standard associated with a corresponding threshold.

[0036] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed by a processor, the processor executes the welding quality detection method as described above.

[0037] An embodiment of the fifth aspect of the present application provides a computer program product, comprising instructions, which, when executed by a processor, cause the processor to execute the welding quality detection method as described above.

[0038] 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

[0039] 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.

[0040] FIG1 is a schematic flow chart of a welding quality detection method provided in some embodiments of the present application;

[0041] FIG2 is a schematic diagram of good welding products provided by some embodiments of the present application;

[0042] FIG3 is a comparison diagram of good welding products and poor welding products provided by some embodiments of the present application;

[0043] FIG4 is an enlarged schematic diagram of region A in FIG3 before and after shear force stretching, provided in some embodiments of the present application;

[0044] FIG5 is a vibration shape comparison diagram of good welding products and poor welding products provided in some embodiments of the present application;

[0045] FIG6 is a schematic structural diagram of a welding quality detection system provided in some embodiments of the present application;

[0046] FIG7 is a structural block diagram of an industrial computer provided in some embodiments of the present application;

[0047] FIG8 is a schematic structural diagram of a welding quality detection device provided in some embodiments of the present application. DETAILED DESCRIPTION

[0048] 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.

[0049] 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.

[0050] In the description of the embodiments of this application, the technical terms "first," "second," etc. are used only to distinguish different objects and should not be understood to indicate or imply relative importance or to implicitly indicate 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 specifically defined.

[0051] 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.

[0052] 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.

[0053] 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).

[0054] 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., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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 device or element referred to 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 the present application.

[0055] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," 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; and 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.

[0056] 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.

[0057] During battery production, the positive and negative electrodes need to be welded to the battery casing or other connection points. Multiple batteries may need to be connected in series or parallel using welded connectors. The battery casing may also need to be welded to complete the sealing. Some batteries with safety protection features may also require a safety valve or explosion-proof valve to be welded to the battery casing. Welding quality is particularly important to the quality of batteries. Each weld point of the battery needs to be inspected to detect welding defects in a timely manner and reduce the outflow of batteries with welding defects.

[0058] When a cold weld or crack develops in the tab adapter weld joint, the cold weld or crack will reduce the contact area, significantly reducing electrical conductivity and increasing contact resistance, which may lead to power loss. At the same time, the increased resistance will increase heat generation when current passes through, which may cause battery overheating over a long period of time. On the other hand, cracks in the weld joint or cold weld will cause the mechanical strength of the joint to decrease, making the joint more likely to break, which may cause serious safety accidents.

[0059] Based on the above considerations, to address the issues of accuracy and efficiency in battery welding defect detection, direct extraction of the inherent acoustic characteristics of the sample can be used for defect detection. This detection method is highly accurate and also improves detection efficiency to a certain extent. It can also set specific acoustic characteristics to conduct in-depth detection and analysis of specific categories or types of defects, providing strong application flexibility.

[0060] The welding quality detection method disclosed in the embodiment of the present application can be used for non-destructive testing of welding parts in various battery production processes, including but not limited to detecting cold welds or cracks in the welding joints of the tab adapter.

[0061] Please refer to Figure 1, which is a flow chart of a welding quality detection method provided by some embodiments of the present application. The present application provides a welding quality detection method, which includes:

[0062] S110, obtaining vibration data of the welding sample at a resonant frequency detected by a vibration detector, wherein the resonant frequency is an excitation frequency at which the welding sample is driven to vibrate by a vibration generator;

[0063] S120, determining at least one vibration parameter of the welding sample based on the vibration data; and

[0064] S130 , in response to at least one of the at least one vibration parameter satisfying a criterion associated with a corresponding threshold value, determining that a welding defect exists in the welding sample.

[0065] Resonance frequency refers to the natural frequency at which an object or system reaches maximum amplitude or vibration speed when driven by an external force. At resonance, the following relationship is satisfied:

[0066] Among them, s is the oscillator displacement, C is the constant term, e is the natural constant, k is the stiffness, t is the time, i is the vibration order, v0 is the initial vibration velocity, F is the oscillator total force, m is the oscillator mass, f0 is the natural frequency of the good welding product, and f is the ultrasonic excitation frequency.

[0067] As a feasible embodiment, the vibration generator can be a device (e.g., an ultrasonic transducer) that utilizes the characteristics of ultrasound to generate vibrations through the elasticity of an object or the nonlinear effects of a medium. The vibration detector can be an accelerometer, a piezoelectric vibration sensor, or a laser vibrometer, without particular limitation herein.

[0068] Each vibration parameter meeting the standards associated with the corresponding threshold value means that when the preset standard is that the corresponding first vibration parameter is less than the corresponding first threshold value, the welding sample has a first type of welding defect. Then, in the process of quality inspection, in response to the detected first vibration parameter being less than the corresponding first threshold value, it is determined that the welding sample has a welding defect, or at least the welding sample has a first type of welding defect. At the same time, when the preset standard is that the corresponding second vibration parameter is greater than the corresponding second threshold value, the welding sample has a second type of welding defect. Then, in the process of quality inspection, in response to the detected second vibration parameter being less than the corresponding second threshold value, it is determined that the welding sample has a welding defect, or at least the welding sample has a second type of welding defect. It will be understood that since the corresponding threshold values ​​and associated standards corresponding to different vibration parameters may be different from each other, satisfying the associated standards in this application may be greater than the corresponding threshold value and / or less than the corresponding threshold value.

[0069] Directly extracting the vibration parameters of weld samples at the resonant frequency for defect detection offers high accuracy, convenience, and efficiency. Poor weld quality can lead to fractures or structural damage. A weld that maintains stable vibration parameters at the resonant frequency indicates good weld quality. Conversely, if vibration parameters meet threshold values ​​at the resonant frequency, this indicates a potential weld defect. This significantly improves both the detection rate and efficiency of weld defects.

[0070] According to some embodiments of the present application, the threshold value of at least one vibration parameter is obtained by statistically analyzing the values ​​of at least one vibration parameter of at least one good welding product at a resonant frequency.

[0071] In this application, the term "good weld" is used to set the standard weld. The purpose of setting the vibration parameter threshold is to determine whether the sample to be tested is qualified based on this threshold in subsequent tests.

[0072] When the object of inspection is the welding quality of the welding joint of the tab and the adapter, the welding samples to be tested and the good welding products are both the tab and the adapter that are welded to each other. Since the tab and the battery cell have been connected before the tab and the adapter are welded, the welding samples to be tested and the good welding products also include the battery cell connected to the corresponding tab. It is understandable that the selection of the welding samples to be tested and the good welding products is determined based on the welding position (object) to be tested, and the welding samples to be tested and the good welding products corresponding to different welding positions to be tested may be different from each other. The welding samples and good welding products corresponding to the same welding position to be tested should be based on the same benchmark, that is, if the welding sample to be tested only includes the battery cell, tab and adapter, then the good welding products should also only include the battery cell, tab and adapter.

[0073] The threshold is set based on good welds because they represent, to a certain extent, the expected, ideal product state. If the vibration response of a weld sample is similar to that of a good weld, the weld sample is considered qualified. Conversely, if the vibration response of the weld sample is far from the threshold, a problem may exist. For example, a poor weld may have caused internal structural instability, resulting in an abnormal vibration response.

[0074] As a feasible implementation, when obtaining the vibration parameter threshold, the threshold value may be obtained by statistically analyzing the values ​​of at least one vibration parameter of a plurality of good welding products at the resonant frequency.

[0075] In vibration testing, good welds are used to set the inspection standard. The purpose of setting the threshold value of each vibration parameter is to judge whether the sample is qualified based on this threshold in subsequent tests.

[0076] By using the measurement data of multiple good welding products, the accuracy of the threshold values ​​of the vibration parameters can be improved, thereby improving the detection rate of welding defects to a certain extent.

[0077] According to some embodiments of the present application, the resonant frequency is obtained by detecting the maximum vibration velocity of at least one good welding product.

[0078] During actual testing, various environmental factors can introduce unwanted noise. This noise is typically random and has a relatively uniform frequency distribution. When the entire testing process is performed at a specific resonant frequency, the amplitude of the signal at that frequency is significantly increased, while the amplitude of noise at other frequencies is relatively small, achieving the desired noise reduction effect. Furthermore, using resonant frequencies can improve signal selectivity and sensitivity, thereby enhancing measurement accuracy.

[0079] By obtaining the resonant frequency as the excitation frequency, the sample vibration signal can reach a peak value, which helps to reduce the impact of noise in the measurement process on the measurement results, thereby improving the measurement accuracy.

[0080] According to some embodiments of the present application, at least one good weld is obtained by the following steps: obtaining the shear force test results of M welding samples out of N welding samples, wherein the N welding samples are welded under the same process conditions, N and M are integers greater than 1, and M<N; in response to the shear force test results of the M welding samples satisfying the good evaluation index, determining that the remaining NM welding samples out of the N welding samples are at least one good weld.

[0081] Due to the high consistency of battery cell manufacturing, the welding differences between the same batch of welding samples obtained by welding under the same process conditions are small. Therefore, a part of the welding samples from the same batch obtained by welding under the same process conditions is selected for shear force testing. When the shear force test results of each welding sample meet the good product evaluation index, it is considered that the welding samples of this batch meet the requirements of good welding products, and the remaining NM welding samples that have not undergone shear force testing can be determined as good welding products.

[0082] It can be understood that the welding environment does not change under the same process conditions, and the welding parameters remain consistent to obtain the same batch of welding samples with theoretically the same parameters.

[0083] As a feasible implementation method, the same batch of welding samples can be divided into multiple equal parts. For example, a batch of welding samples has 420 pieces, which can be divided into 42 equal parts of 10 pieces each. 1-2 welding samples are taken from each equal part for shear force testing, and the remaining welding samples in each equal part are treated as good welding products for subsequent testing.

[0084] By selecting good welding products and using them as evaluation indicators for subsequent testing, the welding quality of the welding samples to be tested can be better evaluated, thereby achieving non-destructive testing.

[0085] According to some embodiments of the present application, for each of the M welding samples, the shear force test result includes the weld mark residual rate of the welding sample under shear force, wherein the weld mark residual rate is the ratio of the number of residual welds of the welding sample after stretching under shear force to the total number of welds of the welding sample.

[0086] Please refer to Figure 2, which is a schematic diagram of a good weld provided by some embodiments of the present application. During the battery manufacturing process, the tab 2 and the adapter 3 are connected via a welded joint 4, where the tab 2 is connected to the battery cell 1. The connection of the welded joint 4 is one of the structural elements of the battery assembly. Under normal circumstances, the tab 2 and the adapter 3 are tightly connected by welding, forming a relatively stable welded joint 4 that can effectively transmit current when the battery is in operation.

[0087] The weld quality assessment of weld joint 4 (also known as the aforementioned good quality evaluation index) generally relies on the following two indicators: shear force and weld mark residual area. Shear force refers to the force required to directly shear weld joint 4, and this value is an indicator of the strength of weld joint 4.

[0088] Please refer to Figures 3-4. Figure 3 is a comparison of a good weld (left half of Figure 3) and a poor weld (right half of Figure 3) provided by some embodiments of the present application. During the welding process, a weld mark area forms on the surface of the weld sample, namely, Area A and Area B in Figure 3. Figure 4 is an enlarged schematic diagram of Area A in Figure 3 before and after shear force stretching, provided by some embodiments of the present application. The weld mark residual rate is the ratio of the number of remaining weld points c in a good weld after stretching under shear force to the total number of weld points c in the good weld. As shown in Figure 4, the total number of weld points in the weld mark area is 27, and the number of remaining weld points c after stretching is 19. Therefore, the weld mark residual area of ​​the weld joint = 19 / 27 * 100% = 70.4%. If this value is greater than 50%, it means that the weld joint is a good weld. If this percentage is between 50% and 100%, it means that most or all of the weld surface of the joint is involved in the weld, and the weld quality is high. If this ratio is low, it may indicate that there is a problem with the quality of the weld joint and the strength of the weld joint may not meet the standards.

[0089] By evaluating the welding quality of the battery tab and the adapter based on the shear force and the weld mark residual rate, good welding products can be obtained, which can better evaluate the welding quality of the battery tab and the adapter.

[0090] According to some embodiments of the present application, for each of the M welding samples, the good product evaluation indicators include: 100N≤τ≤800N, τ is the shear force that the good welding product withstands; 0.5≤R≤1, R is the weld mark residual rate of the good welding product.

[0091] Generally speaking, the shear force satisfies 100N≤τ≤800N, indicating that the strength of the welded joint 4 has reached the preset standard and can withstand a certain amount of pulling or squeezing in daily use without breaking easily.

[0092] As shown in Figure 4, the total number of welds in the weld mark area is 27, and the number of welds c remaining after stretching is 19. Therefore, the weld mark residual area of ​​this weld joint = 19 / 27 * 100% = 70.4%. This value is greater than 50%, indicating that the weld joint is a good weld. If this percentage is between 50% and 100%, it means that most or all of the weld surface of the joint is involved in the weld, and the weld quality is high. If this percentage is lower, it may indicate that the weld joint quality is problematic and the strength of the weld joint may not meet the standard.

[0093] Shear force and weld mark residual rate can be used to characterize the shear strength and welding quality in the welded structure, and to evaluate the actual performance of the welding quality, which can better evaluate the welding quality of the battery tab and the adapter.

[0094] According to some embodiments of the present application, the at least one vibration parameter includes at least one of a characteristic parameter characterizing a vibration shape of the welding sample, a vibration velocity of the welding sample, and a soldering rate of a weld print zone of the welding sample, wherein the soldering rate is a ratio of an area of ​​a soldering region within the weld print zone to an area of ​​the weld print zone.

[0095] When a cold weld occurs in the welding joint 4, the connection strength between the tab 2 and the adapter 3 is reduced, the constraint of the adapter 3 on the weld mark area is weakened, and the vibration speed is significantly increased.

[0096] When a crack occurs in the weld joint 4, the vibrations on both sides of the crack tend to be discrete, and the vibration shape obtained by detection will appear abnormal.

[0097] The soldering rate of the weld mark area refers to the ratio of the soldering area within the weld mark area to the area of ​​the entire weld contact surface, also known as the weld mark area. The soldering rate directly affects the mechanical properties of the weld joint. Generally speaking, the higher the soldering rate, the greater the strength of the weld joint.

[0098] By characterizing whether at least one of the characteristic parameters of the vibration shape of the welding sample, the vibration speed of the welding sample, and the soldering rate of the weld mark area of ​​the welding sample meets the standards associated with the corresponding thresholds, the detection accuracy and efficiency of the welding joint can be improved to a certain extent.

[0099] According to some embodiments of the present application, the characteristic parameter of the mode shape includes the aspect ratio of the mode shape.

[0100] The aspect ratio of the vibration shape can, to some extent, reflect the elastic properties and structural performance of the sample under test during vibration. When cracks appear in welded joints, they create areas of stress concentration, causing local changes in the structural stiffness. This change in stiffness also causes changes in the vibration shape during vibration. Generally, more severe cracks result in greater changes in the vibration shape aspect ratio.

[0101] Please refer to Figure 5, which is a vibration shape comparison diagram of good welding products and poor welding products provided in some embodiments of the present application. In Figure 5, W is the width of the vibration shape, and H is the height of the vibration shape. The left half of Figure 5 is the vibration shape detection image of a good welding product, and the right half of Figure 5 is the vibration shape detection image of a poor welding product. It can be seen that the aspect ratio (W / H) of the vibration shape of the poor welding product is reduced to a certain extent compared to the good welding product. Therefore, by monitoring the change in the aspect ratio of the vibration shape, it is possible to directly determine whether cracks are found in the weld joint (or even the severity of the cracks).

[0102] It should be understood that the aspect ratio of the vibration shape is only one example of a characteristic parameter of the vibration shape. In other embodiments, other characteristic parameters of the vibration shape, such as the area of ​​the vibration shape, may also be used as judgment criteria. Similar to the aspect ratio of the vibration shape, the area of ​​the vibration shape can also reflect the elastic properties and structural performance of the sample under test during vibration. Generally speaking, the more severe the crack, the smaller the area of ​​the vibration shape.

[0103] According to some embodiments of the present application, the corresponding threshold includes a first threshold for the aspect ratio of the mode shape, and the criterion associated with the first threshold is: the aspect ratio of the mode shape is smaller than the first threshold.

[0104] The aspect ratios of the vibration shapes of the plurality of good weld products can be obtained by measuring the vibration shapes of the plurality of good weld products at the resonance frequency, and the first threshold value can be obtained based on the aspect ratios of the vibration shapes of the plurality of good weld products.

[0105] When a weld cracks, the vibrations on both sides of the crack tend to become discrete, resulting in an irregular vibration shape. Therefore, when the aspect ratio of the vibration shape of the weld sample at the resonant frequency is less than a first threshold, a crack has occurred in the weld joint of the weld sample, indicating a weld defect.

[0106] By characterizing whether the aspect ratio of the vibration shape of the welding sample is less than the first threshold, it is possible to quickly determine whether cracks occur in the welding joint of the welding sample, which can improve the detection accuracy and detection efficiency of the welding joint to a certain extent.

[0107] According to some embodiments of the present application, the corresponding threshold includes a second threshold for the vibration velocity of the welding sample, and the criterion associated with the second threshold is that the vibration velocity of the welding sample is greater than the second threshold.

[0108] The second threshold range may be obtained based on the vibration speeds of the plurality of good weld products at the resonance frequency.

[0109] As the connection strength between the tab and the adapter plate decreases, the adapter plate's constraint on the weld print area weakens, and the vibration speed will be significantly enhanced. When the vibration speed of the welding sample at the resonant frequency is greater than the second threshold, there is a cold weld in the welding joint of the welding sample, which means that it is determined that the welding sample has a welding defect.

[0110] By characterizing whether the vibration speed of the welding sample is greater than the second threshold, it is possible to quickly determine whether a cold weld occurs in the welding joint of the welding sample, which can improve the detection accuracy and detection efficiency of the welding joint to a certain extent.

[0111] According to some embodiments of the present application, the corresponding threshold value includes a third threshold value for the soldering rate of the weld mark area, and the standard associated with the third threshold value is: the soldering rate of the weld mark area is less than the third threshold value.

[0112] The third threshold range can be determined based on the soldering rates of multiple good welds at the resonant frequency. Since a higher soldering rate indicates a stronger weld joint, when the soldering rate of a weld sample at the resonant frequency is less than the third threshold, the weld joint strength of the weld sample is insufficient, indicating a weld defect.

[0113] By characterizing whether the soldering rate of the welding sample is less than the third threshold, it is possible to quickly determine whether the connection strength of the welding joint of the welding sample meets the preset standard, which can improve the detection accuracy and efficiency of the welding joint to a certain extent.

[0114] According to some embodiments of the present application, the welding sample includes a tab-to-adapter welding joint of a battery.

[0115] It should be understood that in such an embodiment, the resonant frequency and weld quality judgment threshold for measuring good welds also include the battery tab-to-adapter tab weld joints. That is, the resonant frequency and judgment threshold measured for the good tab-to-adapter tab weld joints will be applied to the welding quality inspection of the tab-to-adapter tab weld joints of the welding sample.

[0116] By obtaining the vibration data of the battery's tab-to-adapter welding joint, it is possible to detect the welding quality of specified parts in the battery.

[0117] According to some embodiments of the present application, the resonant frequency of the tab-to-adapter plate weld joint is obtained by the following steps: driving the good tab-to-adapter plate weld joint to vibrate by a vibration generator, wherein the excitation frequency of the vibration generator gradually changes; detecting the vibration speed of the good tab-to-adapter plate weld joint under the gradually changing excitation frequency by a vibration detector; and determining the excitation frequency corresponding to the good tab-to-adapter plate weld joint when the vibration speed is the maximum as the resonant frequency of the tab-to-adapter plate weld joint.

[0118] A good tab-to-adapter sheet weld joint is obtained by the following steps: obtaining a shear force test result of each of Y tab-to-adapter sheet weld joints among X tab-to-adapter sheet weld joints, wherein the X tab-to-adapter sheet weld joints are welded under the same process conditions, X and Y are integers greater than 1, and Y<X; in response to the shear force test results of each of the Y tab-to-adapter sheet weld joints satisfying a good product evaluation index, determining that the remaining XY tab-to-adapter sheet weld joints among the X tab-to-adapter sheet weld joints are at least one good tab-to-adapter sheet weld joint. Due to the high consistency of battery cell manufacturing, the welding differences between the same batch of tab-adapter welding joints welded under the same process conditions are small. Therefore, a part of the same batch of tab-adapter welding joints welded under the same process conditions is selected for shear force testing. When the shear force test results of each tab-adapter welding joint meet the good product evaluation index, it is considered that the tab-adapter welding joints of this batch meet the requirements of good welding products, and the remaining XY tab-adapter welding joints that have not undergone shear force testing can be determined as good tab-adapter welding joints.

[0119] By gradually changing the excitation frequency of the vibration generator, it is possible to easily determine at which excitation frequency the vibration speed of the good tab-to-adapter welding joint is the largest, thereby obtaining the resonant frequency of the tab-to-adapter welding joint.

[0120] According to some embodiments of the present application, the excitation frequency of the vibration generator gradually changes in the following manner: the excitation frequency of the vibration generator increases from a first frequency to a second frequency in a frequency step, or decreases from the second frequency to the first frequency in a frequency step, wherein the second frequency is greater than the first frequency.

[0121] Resonance frequency refers to the natural frequency at which an object or system reaches maximum amplitude or vibration speed when driven by an external force. At resonance, the following relationship is satisfied:

[0122] Among them, s is the oscillator displacement, C is the constant term, e is the natural constant, k is the stiffness, t is the time, i is the vibration order, v0 is the initial vibration velocity, F is the oscillator total force, m is the oscillator mass, f0 is the natural frequency of the good welding product, and ff is the ultrasonic excitation frequency.

[0123] As a feasible embodiment, the vibration generator can be a device (e.g., an ultrasonic transducer) that utilizes the characteristics of ultrasound to generate vibrations through the elasticity of an object or the nonlinear effects of a medium. The vibration detector can be an accelerometer, a piezoelectric vibration sensor, or a laser vibrometer, without particular limitation herein.

[0124] By gradually increasing the excitation frequency in frequency steps, the response of the good tab-to-adapter weld joint at different excitation frequencies can be observed, over-excitation can be reduced, and it can be easily determined at which excitation frequency the vibration speed of the good tab-to-adapter weld joint is the largest, thereby obtaining the resonant frequency of the tab-to-adapter weld joint.

[0125] According to some embodiments of the present application, the first frequency is 20 kHz, the second frequency is 800 kHz, and the frequency step is 1 to 5 kHz.

[0126] By setting an appropriate frequency step, a more accurate resonant frequency can be found, thereby improving the accuracy of detection.

[0127] Please refer to Figure 6, which is a schematic diagram of the structure of a welding quality detection system provided by some embodiments of the present application. The present application provides a welding quality detection system, comprising: a vibration generator 8, a vibration detector 7, and an industrial computer 11, wherein the industrial computer 11 includes a memory storing instructions; and a processor configured to execute the instructions to perform operations, the operations including: driving the welding sample 6 to vibrate at a resonant frequency via the vibration generator 8; obtaining vibration data of the welding sample 6 at the resonant frequency detected by the vibration detector 7; determining at least one vibration parameter of the welding sample 6 based on the vibration data; and determining that the welding sample 6 has a welding defect in response to at least one of the at least one vibration parameter meeting a standard associated with a corresponding threshold.

[0128] Please refer to Figure 7, which is a block diagram of an industrial computer provided in some embodiments of the present application. Industrial computer 11 is intended to represent various forms of digital electronic computer equipment, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The components shown herein, their connections and relationships, and their functions are provided for illustrative purposes only.

[0129] As shown in Figure 7, the industrial computer 11 includes a processor 111, which can perform various appropriate actions and processes according to computer programs stored in a read-only memory (ROM) 112 or instructions loaded from a storage unit 118 into a random access memory (RAM) 113. RAM 113 can also store various programs and data required for the operation of the industrial computer 11. The computing unit 111, ROM 112, and RAM 113 are interconnected via a bus 114. An input / output (I / O) interface 115 is also connected to the bus 114.

[0130] Multiple components within the industrial computer 11 are connected to the I / O interface 115, including an input unit 116, an output unit 117, a storage unit 118, and a communication unit 119. The input unit 116 can be any type of device capable of inputting information into the industrial computer 11. It can receive input numeric or character information and generate key signal input related to user settings and / or function control of an electronic device. It may include, but is not limited to, a mouse, keyboard, touch screen, trackpad, trackball, joystick, microphone, and / or remote control. The output unit 117 can be any type of device capable of presenting information, and may include, but is not limited to, a display, a speaker, a video / audio output terminal, a vibrator, and / or a printer. The storage unit 118 may include, but is not limited to, a magnetic disk or an optical disk. The communication unit 119 allows the industrial computer 11 to exchange information / data with other devices via computer networks such as the Internet and / or various telecommunication networks. It may include, but is not limited to, a modem, a network card, an infrared communication device, a wireless communication transceiver, and / or a chipset.

[0131] Processor 111 can be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of processor 111 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various computing units that run machine learning model algorithms, a digital signal processor (DSP), and any other suitable processor, controller, microcontroller, etc. Processor 111 executes the various methods and processes described above, such as the welding quality detection method described in the aforementioned embodiments.

[0132] A welding quality inspection system directly extracts the vibration parameters of weld samples at their resonant frequencies for defect detection, offering high accuracy, convenience, and efficiency. Poor weld quality can lead to fractures or structural damage. A weld that maintains stable vibration parameters at its resonant frequency indicates good weld quality. Conversely, if vibration parameters meet thresholds at the resonant frequency, this indicates a potential weld defect. This significantly improves both the detection rate and efficiency of weld defects.

[0133] 6 , according to some embodiments of the present application, a welding quality inspection system further includes a vibration isolation platform 5 , which is used to support the welding sample during the period when the welding sample vibrates at the resonant frequency.

[0134] The vibration isolation platform 5 can isolate and control the vibration interference of the external environment on the welding sample during the vibration test, thereby improving the accuracy of the test. As a feasible embodiment, the vibration isolation platform 5 can be an air-floating vibration isolation platform, which isolates the platform from its support through air springs to isolate external vibrations.

[0135] The vibration isolation platform 5 can isolate the interference of environmental vibration and improve the stability and accuracy of measurement.

[0136] According to some embodiments of the present application, the vibration wave generated by the vibration generator is transmitted to the vibration isolation platform along a first direction, and the first direction forms an acute angle θ with the surface of the vibration isolation platform supporting the welding sample.

[0137] A vibration generator is a device used to create vibrations at a specific excitation frequency. The vibration waves produced by the vibration generator are usually the physical manifestation of the excitation frequency. The vibration frequency of the vibration wave determines the speed of the vibration.

[0138] The vibration wave generated by the vibration generator generally propagates in the same direction as the vibration direction of the vibration sounder, so the vibration direction of the vibration generator determines the original propagation direction of the vibration wave.

[0139] Using an acute angle to project light into the weld sample can reduce measurement errors and improve detection accuracy. At the same time, an acute angle of incidence can extend the vibration path, allowing for more accurate measurement results.

[0140] According to some embodiments of the present application, the acute angle θ satisfies: 40°≤θ≤60°.

[0141] Using an angle of 40°-60° to penetrate the welding sample can reduce measurement errors and improve detection accuracy. At the same time, an angle of 40°-60° can make the vibration path longer, so more accurate measurement results can be obtained.

[0142] According to some embodiments of the present application, a vertical distance H between the vibration detector and the welding sample satisfies: 20 mm ≤ H ≤ 50 mm.

[0143] The vertical distance H between the vibration detector and the welding sample can be the minimum distance between the detection port of the vibration detector and the surface of the welding sample closest to the vibration sensor, wherein the detection port of the vibration detector can be the opening of the vibration detector detection position shell, or it can be the plane where the sensor of the vibration detector is located.

[0144] By adjusting the vertical distance between the vibration detector and the welding sample, the attenuation of the detection signal can be reduced, and the interference of environmental noise can be reduced, thereby improving the detection accuracy.

[0145] According to some embodiments of the present application, the vibration generator includes an ultrasonic transducer 8, which is used to generate ultrasonic waves under the excitation of an excitation signal and project the ultrasonic waves onto the welding sample 6 to drive the welding sample 6 to vibrate at a resonant frequency.

[0146] Ultrasonic transducer 8 converts the voltage signal into ultrasonic waves, which are then projected onto the weld joint. Ultrasonic transducer 8 provides highly precise and consistent power, enabling precise control of the frequency and amplitude of vibration. Compared to other types of vibration generators, ultrasonic transducer 8 offers higher energy conversion efficiency, is compact, easy to install and maintain, and has a fast response speed, producing strong vibrations in a short period of time.

[0147] Since the ultrasonic transducer 8 does not need to be in direct contact with the welding sample to generate vibration, the mechanical connection between the vibration generator and the welding sample is avoided to a certain extent. Therefore, the ultrasonic transducer 8 can improve the measurement stability and detection efficiency to a certain extent.

[0148] According to some embodiments of the present application, a welding quality detection system further includes a signal generator 10 for generating a voltage signal; and a power amplifier 9 for amplifying the voltage signal to provide an excitation signal.

[0149] The signal generator 10 and the power amplifier 9 are often used in pairs. The signal generator 10 generates the required voltage signal, and the power amplifier 9 amplifies the signal so that the excitation signal has enough energy to drive subsequent devices to perform specific operations.

[0150] According to some embodiments of the present application, the welding sample includes a tab-to-adapter welding joint of a battery.

[0151] Referring to Figure 2, when a good weld product includes a cell 1, tab 2, adapter 3, and weld joint 4, the weld sample also includes the cell, tab, adapter, and weld joint. The weld sample and good weld product corresponding to the same weld position to be inspected should be based on the same benchmark.

[0152] By obtaining the vibration data of the battery's tab-to-adapter welding joint, it is possible to detect the welding quality of specified parts in the battery.

[0153] It should be understood that the tab-to-adapter tab welding joint is only an example, and in other embodiments, the welding quality inspection may be performed on other appropriate welding locations of the battery.

[0154] Please refer to FIG8 , which is a schematic diagram of the structure of a welding quality detection device provided in some embodiments of the present application. The present application provides a welding quality detection device 800, including:

[0155] The first module 801 is used to obtain vibration data of the welding sample at a resonant frequency detected by a vibration detector, wherein the resonant frequency is an excitation frequency at which the welding sample is driven to vibrate by a vibration generator.

[0156] The second module 802 is configured to determine at least one vibration parameter of the welding sample based on the vibration data.

[0157] The third module 803 is configured to determine that a welding defect exists in the welding sample in response to at least one of the at least one vibration parameter meeting a criterion associated with a corresponding threshold.

[0158] Since the first module 801 , the second module 802 and the third module 803 in the welding quality inspection device 800 may respectively correspond to steps S110 to S130 in FIG. 1 , details of each aspect thereof will not be repeated here.

[0159] It should be noted that the functions of the various modules discussed herein can be divided into multiple modules, and / or at least some functions of multiple modules can be combined into a single module. The specific module discussed herein performing an action includes the specific module itself performing the action, or alternatively, the specific module calling or otherwise accessing another component or module that performs the action (or performs the action in conjunction with the specific module). Therefore, the specific module that performs an action can include the specific module itself that performs the action and / or another module that the specific module calls or otherwise accesses to perform the action.

[0160] It should also be understood that various technologies can be described herein in the general context of software hardware elements or program modules. The above modules described about Fig. 8 can be implemented in hardware or in the hardware in conjunction with software and / or firmware. For example, these modules can be implemented as computer program code / instructions, which are configured to be executed in one or more processors and stored in a computer-readable storage medium. Alternatively, these modules can be implemented as hardware logic / circuits. Hardware logic / circuits can include integrated circuit chips (which include processors (for example, central processing unit (Central Processing Unit, CPU), microcontroller, microprocessor, digital signal processor (Digital Signal Processor, DSP) etc.), memory, one or more communication interfaces, and / or one or more components in other circuits), and can execute received program code and / or include embedded firmware to perform functions.

[0161] An embodiment of the present application further provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed by a processor, the processor executes the welding quality detection method in any of the above embodiments.

[0162] Computer-readable storage media include volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information, such as computer-readable instructions, data structures, program modules or other data. Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD), or other optical storage devices, magnetic cassettes, magnetic tape, magnetic disk storage devices or other magnetic storage devices, or any other non-transmission media that can be used to store information for access by a computer device. In contrast, communication media can implement computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transmission mechanism. Computer-readable storage media as defined herein does not include communication media.

[0163] The present application also provides a computer program product including instructions that, when executed by a processor, cause the processor to perform the welding quality detection method described in any of the above embodiments. Such a computer program or instructions have been described above with respect to FIG. 7 and will not be further described here for the sake of brevity.

[0164] According to some embodiments of the present application, as shown in Figures 1-6, the embodiments of the present application provide a welding quality detection method, including:

[0165] Vibration data of a welding sample at a resonant frequency detected by a scanning laser vibrometer lens is obtained, wherein the resonant frequency is an excitation frequency at which the welding sample is driven to vibrate by a vibration generator; based on the vibration data, at least one vibration parameter of the welding sample is determined, the vibration parameter including at least one of an aspect ratio of a vibration shape characterizing the welding sample, a vibration velocity of the welding sample, and a soldering rate of a weld mark area of ​​the welding sample; and in response to at least one of the at least one vibration parameter satisfying a criterion associated with a corresponding threshold value, a welding defect is determined to exist in the welding sample.

[0166] Before measuring the welding sample, a threshold value corresponding to the at least one vibration parameter is obtained by statistically analyzing the values ​​of at least one vibration parameter of a plurality of good welding products at the resonance frequency.

[0167] Among the multiple good welding products are copper tab-adapter plate welding joints and aluminum tab-adapter plate welding joints: through tensile testing, the average shear forces of the copper tab-adapter plate welding joints and the aluminum tab-adapter plate welding joints are 256N and 231N respectively, and the residual areas of weld marks are 90% and 85% respectively, and they are selected as good welding products.

[0168] As a feasible implementation method, a total of 420 good welds were selected and classified according to copper tab-to-adapter weld joints and aluminum tab-to-adapter weld joints, and placed in batches on an air-floating vibration isolation platform. Each batch of good welds was driven to vibrate using an ultrasonic transducer excitation frequency. The excitation frequency range was 20 to 800 kHz, the frequency interval was 1 to 5 kHz, and the ultrasonic incident angle was 40 to 60 degrees. A scanning laser vibrometer lens was used to detect the sample vibration signal at a distance of approximately 20 to 50 mm from the good welds. As a feasible implementation method, the excitation frequency range was 20 to 800 kHz, the frequency interval was 2 kHz, and the ultrasonic incident angle was 45 degrees. A scanning laser vibrometer lens was used to detect the sample vibration signal at a distance of approximately 40 mm from the good welds. The average resonant frequency of the good copper tab-to-adapter weld joints was 301 kHz, and the average resonant frequency of the good aluminum tab-to-adapter weld joints was 165 kHz.

[0169] The ultrasonic transducer excitation frequency was set to the resonant frequency corresponding to a good weld product. The vibration parameters of multiple good weld products at the resonant frequency were measured. Based on the aspect ratio of the vibration shapes of the multiple good weld products, a first threshold value Th1 = W / H ≥ 0.8 was determined, where W is the width of the vibration shape and H is the height of the vibration shape. The vibration velocities of the multiple good weld products at the resonant frequency were measured, and both vibration velocities were less than 1E-05 m / s, indicating a second threshold value Th2 ≤ 1E-05 m / s. The soldering rates of the multiple good weld products at the resonant frequency were measured, and both soldering rates met a third threshold value Th3 ≥ 0.5.

[0170] The excitation frequency of the ultrasonic transducer is maintained at the resonant frequency corresponding to the good welding product, and the vibration parameters of multiple welding samples at the resonant frequency are measured respectively, and compared with at least one of the first threshold, the second threshold and the third threshold. In response to at least one of the above at least one vibration parameter meeting the standard associated with the corresponding threshold, that is, when the aspect ratio of the vibration shape of the welding sample is less than the first threshold, the vibration speed of the welding sample is greater than the second threshold, and the soldering rate of the weld mark area of ​​the welding sample is less than the third threshold, when at least one of the three conditions is met, it is output that the welding sample has a welding defect, thereby detecting and intercepting the quality defects in the corresponding welding sample.

[0171] 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 welding quality detection method, comprising: Acquiring vibration data of the welding sample at a resonant frequency detected by a vibration detector, wherein the resonant frequency is an excitation frequency at which the welding sample is driven to vibrate by a vibration generator; determining at least one vibration parameter of the welding sample based on the vibration data; and In response to at least one of the at least one vibration parameter satisfying a criterion associated with a corresponding threshold value, it is determined that the welding sample has a welding defect.

2. The method according to claim 1, wherein: The threshold value of each of the at least one vibration parameter is obtained by statistically analyzing the values ​​of each of the at least one vibration parameter of at least one good welding product at the resonance frequency.

3. The method according to claim 1 or 2, wherein: The resonance frequency is obtained by detecting the maximum vibration speed of at least one good welding product.

4. The method according to claim 2 or 3, wherein: The at least one good welding product is obtained by the following steps: Obtaining shear force test results of M welding samples among N welding samples, wherein the N welding samples are welded under the same process conditions, N and M are integers greater than 1, and M<N; In response to the shear force test results of the M welding samples satisfying the good product evaluation index, the remaining NM welding samples of the N welding samples are determined to be the at least one good welding product.

5. The method according to claim 4, wherein: For each of the M welding samples, the shear force test result includes a weld mark residual rate of the welding sample under the shear force, wherein the weld mark residual rate is the ratio of the number of residual welds of the welding sample after stretching under the shear force to the total number of welds of the welding sample.

6. The method according to claim 5, wherein: For each welding sample in the M welding samples, the good product evaluation index includes: 100N≤τ≤800N, τ is the shear force borne by the good welding product; 0.5≤R≤1, R is the weld mark residual rate of the good welding product.

7. The method according to any one of claims 1 to 6, wherein: The at least one vibration parameter includes at least one of a characteristic parameter characterizing a vibration shape of the welding sample, a vibration velocity of the welding sample, and a soldering rate of a weld print zone of the welding sample, wherein the soldering rate is a ratio of an area of ​​a soldering region within the weld print zone to an area of ​​the weld print zone.

8. The method according to claim 7, wherein: The characteristic parameter of the mode shape includes an aspect ratio of the mode shape.

9. The method according to claim 8, wherein: The corresponding thresholds include a first threshold for an aspect ratio of the mode shape, and a criterion associated with the first threshold is that the aspect ratio of the mode shape is smaller than the first threshold.

10. The method according to any one of claims 7 to 9, wherein: The corresponding thresholds include a second threshold for the vibration speed of the welding sample, and a criterion associated with the second threshold is that the vibration speed of the welding sample is greater than the second threshold.

11. The method according to any one of claims 7 to 10, wherein: The corresponding thresholds include a third threshold for the soldering rate of the weld print area, and a criterion associated with the third threshold is that the soldering rate of the weld print area is less than the third threshold.

12. The method according to any one of claims 1 to 11, wherein: The welding sample includes a battery tab-adapter welding joint.

13. The method according to claim 12, wherein: The resonant frequency of the tab-adapter welding joint is obtained by the following steps: The vibration generator is used to drive the good quality electrode tab-adapter welding joint to vibrate, wherein the excitation frequency of the vibration generator changes gradually; Detecting the vibration speed of the good tab-adapter welding joint under the gradually changing excitation frequency by the vibration detector; and The excitation frequency corresponding to the good product of the tab-adapter plate welding joint when the vibration speed is the maximum is determined as the resonance frequency of the tab-adapter plate welding joint.

14. The method according to claim 13, wherein: The excitation frequency of the vibration generator is gradually changed in the following manner: The excitation frequency of the vibration generator increases from a first frequency to a second frequency in a frequency step, or decreases from the second frequency to the first frequency in the frequency step, wherein the second frequency is greater than the first frequency.

15. The method according to claim 14, wherein: The first frequency is 20 kHz, the second frequency is 800 kHz, and the frequency step is 1 to 5 kHz.

16. A welding quality detection system, comprising: Vibration generator; Vibration detectors; A memory storing instructions; as well as A processor configured to execute the instructions to perform operations, the operations comprising: Acquiring vibration data of the welding sample at a resonance frequency detected by the vibration detector, wherein the resonance frequency is an excitation frequency at which the welding sample is driven to vibrate by the vibration generator; determining at least one vibration parameter of the welding sample based on the vibration data; and In response to at least one of the at least one vibration parameter satisfying a criterion associated with a corresponding threshold value, it is determined that the welding sample has a welding defect.

17. The welding quality inspection system according to claim 16, wherein: Also included is a vibration isolation platform for supporting the welding sample during vibration of the welding sample at the resonant frequency.

18. The welding quality inspection system according to claim 17, wherein: The vibration wave generated by the vibration generator is transmitted to the vibration isolation platform along a first direction, and an acute angle θ is formed between the first direction and the surface of the vibration isolation platform supporting the welding sample.

19. The welding quality inspection system according to claim 18, wherein: The acute angle θ satisfies: 40°≤θ≤60°.

20. The welding quality inspection system according to any one of claims 16 to 19, wherein: A vertical distance H between the vibration detector and the welding sample satisfies: 20 mm ≤ H ≤ 50 mm.

21. The welding quality inspection system according to any one of claims 16 to 20, wherein: The vibration generator includes an ultrasonic transducer, which is used to generate ultrasonic waves under the excitation of an excitation signal and project the ultrasonic waves onto the welding sample to drive the welding sample to vibrate at the resonance frequency.

22. The welding quality inspection system according to claim 21, wherein: Also includes: A signal generator, used for generating a voltage signal; as well as A power amplifier is used to amplify the voltage signal to provide the excitation signal.

23. The welding quality inspection system according to any one of claims 16 to 22, wherein: The welding sample includes a battery tab-adapter welding joint.

24. A welding quality detection device, comprising: A first module is used to obtain vibration data of a welding sample at a resonance frequency detected by a vibration detector, wherein the resonance frequency is an excitation frequency at which the welding sample is driven to vibrate by the vibration generator; A second module for determining at least one vibration parameter of the welding sample based on the vibration data; and A third module is configured to determine that a welding defect exists in the welding sample in response to at least one of the at least one vibration parameter satisfying a criterion associated with a corresponding threshold value.

25. A computer-readable storage medium having instructions stored thereon, wherein when the instructions are executed by a processor, the processor is caused to execute the method according to any one of claims 1 to 15.

26. A computer program product comprising instructions, which, when executed by a processor, cause the processor to perform the method according to any one of claims 1 to 15.

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