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

Abstract

The invention 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, and belongs to the technical field of batteries. The welding quality detection method comprises the steps that vibration data, detected by a vibration detector, of a welding sample under the resonance frequency is obtained, and the resonance frequency is the excitation frequency at which the welding sample is driven by a vibration generator to vibrate; 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 meeting the standard associated with the corresponding threshold value, determining that the welding sample has the welding defect. Defect detection is carried out by directly extracting vibration parameters of a welding sample, and the method has the characteristics of high detection precision and high detection efficiency.

Description

Technical Field

[0001] 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

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

[0003] 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. Summary of the invention

[0004] The present application aims to solve at least one of the technical problems in the background technology. 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.

[0005] An embodiment of the first aspect of the present application provides a welding quality detection method, the method comprising: acquiring 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; based on the vibration data, determining at least one vibration parameter of the welding sample; and in response to at least one of the at least one vibration parameter satisfying a standard associated with a corresponding threshold, determining that a welding defect exists in the welding sample.

[0006] In the technical solution of the embodiment of the present application, the vibration parameters of the welding sample at the resonant frequency are directly extracted for defect detection, which has the characteristics of high detection accuracy, convenience and high efficiency. If the welding part can keep the various vibration parameters stable at the resonant frequency, it means that the welding quality is good. On the contrary, if the various vibration parameters meet the standards associated with the corresponding thresholds at the resonant frequency, it means that there may be problems with the welding part, which improves the detection rate of welding defects to a certain extent.

[0007] 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 of at least one good weld at the resonant frequency. In the vibration test, the good weld is used to set the inspection standard, and the purpose of setting the threshold value of each vibration parameter is to determine whether the weld sample to be tested is qualified based on the threshold value in subsequent tests.

[0008] In some embodiments, the resonant frequency is obtained by detecting the maximum vibration speed of at least one good weld product. By obtaining the resonant frequency as the excitation frequency, the sample vibration signal can reach a peak value, which helps to reduce the influence of noise in the measurement process on the measurement result, thereby improving the measurement accuracy.

[0009] In some embodiments, at least one good welding product is obtained by the following steps: obtaining the shear force test results of each of M welding samples in 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 each of the M welding samples satisfying the good product evaluation index, determining that the remaining NM welding samples in the N welding samples are at least one good welding product. Due to the high consistency of battery cell manufacturing, the welding difference between the same batch of welding samples welded under the same process conditions is small, so by selecting a part of the same batch of welding samples welded under the same process conditions 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 the batch meet the requirements of good welding products, and the remaining NM welding samples that have not been sheared can be determined as good welding products. In some embodiments, for each welding sample in 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 weld points of the welding sample after stretching under shear force to the total number of weld points of the welding sample. By evaluating the welding quality between 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 between the battery tab and the adapter.

[0010] In some embodiments, 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. The shear force and weld mark residual rate can be used to characterize the shear strength and welding quality in the welding structure, and to evaluate the actual performance of the welding quality, so as to better evaluate the welding quality of the battery tab and the adapter.

[0011] 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 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.

[0012] 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.

[0013] In some embodiments, the characteristic parameter of the vibration shape includes the aspect ratio of the vibration shape. By monitoring the change of the aspect ratio of the vibration shape, it is possible to directly determine whether cracks are found in the welding joint and the severity of the cracks, thereby improving the detection efficiency.

[0014] In some embodiments, the corresponding threshold includes a first threshold for the aspect ratio of the vibration shape, and the standard associated with the first threshold is that the aspect ratio of the vibration shape is less than the first threshold. 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.

[0015] In some embodiments, the corresponding threshold value includes a second threshold value for the vibration speed of the welding sample, and the standard associated with the second threshold value is that the vibration speed of the welding sample is greater than the second threshold value. By characterizing whether the vibration speed of the welding sample is greater than the second threshold value, 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.

[0016] In some embodiments, the corresponding threshold includes a third threshold for the soldering rate of the weld mark area, and the standard associated with the third threshold is: the soldering rate of the weld mark area is less than the third threshold. By characterizing whether the soldering rate of the welding sample is less than the third threshold, it can be quickly determined whether the connection strength of the welding joint of the welding sample meets the preset standard, which can improve the detection accuracy and detection efficiency of the welding joint to a certain extent.

[0017] In some embodiments, the welding sample is placed on a vibration isolation platform while the welding sample is vibrating at the resonant frequency. The vibration isolation platform can isolate the interference of environmental vibration and improve the stability and accuracy of the measurement.

[0018] In some embodiments, the vibration generator includes an ultrasonic transducer. The ultrasonic transducer can further improve the stability of the measurement and the detection efficiency.

[0019] In some embodiments, the welding sample includes a battery tab-adapter welding joint. By acquiring vibration data of the battery tab-adapter welding joint, the welding quality of a specific part of the battery can be detected.

[0020] In some embodiments, the resonant frequency of the tab-to-adapter welding joint is obtained by the following steps: driving the good tab-to-adapter welding 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 welding joint under the gradually changing excitation frequency by a vibration detector; and determining the excitation frequency corresponding to the good tab-to-adapter welding joint when the vibration speed is the maximum as the resonant frequency of the tab-to-adapter welding joint. By gradually changing the excitation frequency of the vibration generator, it is easy to determine at which excitation frequency the vibration speed of the good tab-to-adapter welding joint is the maximum, thereby obtaining the resonant frequency of the tab-to-adapter welding joint.

[0021] In some embodiments, the excitation frequency of the vibration generator is gradually changed in the following manner: the excitation frequency of the vibration generator is increased from the first frequency to the second frequency in a frequency step, or is decreased from the second frequency to the first frequency in a frequency step, wherein the second frequency is greater than the first frequency. By gradually increasing the excitation frequency in a frequency step, the response of the good tab-to-adapter weld joint at different excitation frequencies can be observed, overexcitation 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 resonance frequency of the tab-to-adapter weld joint.

[0022] In some embodiments, the first frequency is 20 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.

[0023] 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; acquiring 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 satisfying a standard associated with a corresponding threshold.

[0024] 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 inspection accuracy, convenience and efficiency.

[0025] In some embodiments, a welding quality inspection system further includes a vibration isolation platform, which is used to carry the welding sample during the period when the welding sample vibrates at the resonant frequency. The vibration isolation platform can isolate the interference of environmental vibration and improve the stability and accuracy of the measurement.

[0026] In some embodiments, 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. Incident on the welding sample at an acute angle can reduce measurement errors and improve the accuracy of detection. At the same time, the acute angle of incidence can make the vibration path longer, and more accurate measurement results can be obtained.

[0027] In some embodiments, the acute angle θ satisfies: 40°≤θ≤60°. Incident on the welding sample at an angle of 40°-60° can reduce measurement errors and improve detection accuracy. At the same time, incident at an angle of 40°-60° can make the vibration path longer, and more accurate measurement results can be obtained.

[0028] 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.

[0029] In some embodiments, the vibration generator includes an ultrasonic transducer, which is used to generate ultrasonic waves under the stimulation of an excitation signal, and project the ultrasonic waves onto the welding sample to drive the welding sample to vibrate at a resonant frequency. The ultrasonic transducer can improve the stability of the measurement and the detection efficiency to a certain extent.

[0030] In some embodiments, a welding quality detection 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.

[0031] In some embodiments, the welding sample includes a battery tab-adapter welding joint. By acquiring vibration data of the battery tab-adapter welding joint, the welding quality of a specific part of the battery can be detected.

[0032] 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 of the welding sample driven to vibrate by 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 parameter satisfying a standard associated with a corresponding threshold.

[0033] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium on which instructions are stored. When the instructions are executed by a processor, the processor executes the welding quality detection method as described above.

[0034] An embodiment of the fifth aspect of the present application provides a computer program product, comprising instructions, which, when executed by a processor, causes the processor to execute the welding quality detection method as described above.

[0035] 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

[0036] 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.

[0037] Figure 1 A schematic flow chart of a welding quality detection method provided in some embodiments of the present application;

[0038] Figure 2 A schematic diagram of good welding products provided in some embodiments of the present application;

[0039] Figure 3 A comparison chart of good welding products and bad welding products provided in some embodiments of the present application;

[0040] Figure 4 Some embodiments of the present application provide Figure 3 The enlarged schematic diagram of area A in the middle before and after shear force stretching;

[0041] Figure 5 A vibration shape comparison diagram of good welding products and bad welding products provided in some embodiments of the present application;

[0042] Figure 6 A schematic diagram of the structure of a welding quality detection system provided in some embodiments of the present application;

[0043] Figure 7 A structural block diagram of an industrial computer provided in some embodiments of the present application;

[0044] Figure 8 A schematic diagram of the structure of a welding quality detection device provided in some embodiments of the present application. DETAILED DESCRIPTION

[0045] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0047] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0050] 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).

[0051] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0052] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0053] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0054] During the production process of batteries, the positive and negative electrodes of the batteries need to be welded to the battery case or other connection parts. Multiple batteries may need to be connected in series or in parallel through welding connecting plates. The battery case may need to be welded to complete the sealing. Some batteries with safety protection functions may also need to weld the safety valve or explosion-proof valve to the battery case. The welding quality is particularly important for the quality of the battery. It is necessary to inspect each welding part of the battery to detect welding defects in time and reduce the outflow of batteries with welding defects.

[0055] When the welding joint of the tab adapter is cold-welded or cracked, the cold-welded or cracked joint will reduce the contact area, significantly reduce the conductivity, and increase the contact resistance, which may cause power loss. At the same time, the increased resistance will increase the heat generated when the current passes through, which may cause the battery to overheat over a long period of time. On the other hand, cracks in the welding joint or cold-welded welds will cause the mechanical strength of the joint to weaken, making the joint easy to break, which may cause serious safety accidents.

[0056] Based on the above considerations, in order to solve the problem of battery welding defect detection accuracy and detection efficiency, the inherent acoustic characteristics of the sample can be directly extracted for defect detection. This detection method has high accuracy and improves the detection efficiency to a certain extent. At the same time, specific acoustic characteristics can be set to conduct in-depth detection and analysis of specific categories or types of defects, which has strong application flexibility.

[0057] The welding quality detection method disclosed in the embodiment of the present application can be used for non-destructive detection of welding parts in various battery production processes, including but not limited to detecting cold welds or cracks in welding joints of tab adapters.

[0058] Please refer to Figure 1 , Figure 1 A schematic diagram of a welding quality detection method provided in some embodiments of the present application. The present application provides a welding quality detection method, the method comprising:

[0059] S110, obtaining vibration data of the 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 a vibration generator;

[0060] S120, determining at least one vibration parameter of the welding sample based on the vibration data; and

[0061] 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.

[0062] Resonance frequency refers to the natural frequency at which an object or system can reach the maximum amplitude or vibration speed when driven by an external force. The following relationship is satisfied at resonance:

[0063]

[0064] 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 total force of the oscillator, m is the mass of the oscillator, f0 is the natural frequency of the good welding product, and f is the ultrasonic excitation frequency.

[0065] As a feasible implementation, the vibration generator may 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 effect of a medium. The vibration detector may be an acceleration sensor, a piezoelectric vibration sensor, or a laser vibrometer, which is not specifically limited here.

[0066] Each vibration parameter satisfies the standard related to the corresponding threshold value, which 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 can be understood that, since the corresponding threshold values ​​corresponding to different vibration parameters and the associated standards may be different from each other, the associated standards satisfied in the present application may be greater than the corresponding threshold value and / or less than the corresponding threshold value.

[0067] By directly extracting the vibration parameters of the welding sample at the resonant frequency for defect detection, it has the characteristics of high detection accuracy, convenience and efficiency. If the welding quality is not good, problems such as fracture or structural damage may occur. If the welding part can keep the various vibration parameters stable at the resonant frequency, it means that the welding quality is good. On the contrary, if the various vibration parameters meet the standards associated with the corresponding thresholds at the resonant frequency, it means that there may be problems at the welding part, which improves the detection rate and detection efficiency of welding defects to a certain extent.

[0068] 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 resonance frequency.

[0069] In this application, the good welding product is used to set the standard welding parts. The purpose of setting the vibration parameter threshold is to judge whether the sample to be tested is qualified according to this threshold in the subsequent test.

[0070] When the object of detection is the welding quality of the welding joint between the pole lug and the adapter, the welding samples to be tested and the good welding products are the pole lugs and the adapter that are welded to each other. Since the pole lugs and the battery cells are already connected before the pole lugs and the adapter are welded, the welding samples to be tested and the good welding products also include the battery cells correspondingly connected to the corresponding pole lugs. It can be understood 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 detected, and the welding samples to be tested and the good welding products corresponding to different welding positions to be detected may be different from each other. The welding samples and good welding products corresponding to the same welding position to be detected should be based on the same benchmark, that is, if the welding samples to be tested only include the battery cells, pole lugs and the adapter, the good welding products should also only include the battery cells, pole lugs and the adapter.

[0071] Good welding products are selected to set this threshold because good welding products represent the expected and ideal product status to a certain extent. If the vibration response of a welding sample to be tested is similar to the response of good welding products, then the welding sample can be considered qualified. On the contrary, if the vibration response of the welding sample to be tested is far away from this threshold range, then there may be a problem. For example, there may be a problem of poor welding in the welding sample, which causes the instability of the internal structure and thus produces an abnormal vibration response.

[0072] 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 resonance frequency.

[0073] In vibration testing, good welding products are used to set the inspection standard. The purpose of setting the threshold value of each vibration parameter is to judge whether the sample to be tested is qualified based on this threshold value in subsequent tests.

[0074] 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.

[0075] According to some embodiments of the present application, the resonant frequency is obtained by detecting the maximum vibration speed of at least one good welding product.

[0076] In the actual detection process, unnecessary noise will be introduced due to various environmental factors. This noise is usually random and the frequency distribution is relatively uniform. When the entire detection process is carried out at a specific resonant frequency, the amplitude of the frequency signal can be greatly increased, and the noise amplitude of other frequencies is relatively small, which achieves the effect of noise reduction. At the same time, the use of resonant frequency can improve the selectivity and sensitivity of the signal, thereby improving the measurement accuracy.

[0077] By taking 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.

[0078] 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 each satisfying the good product evaluation index, determining that the remaining NM welding samples out of the N welding samples are at least one good weld.

[0079] Due to the high consistency of battery cell manufacturing, the welding differences between the same batch of welding samples obtained under the same process conditions are small. Therefore, a part of the welding samples from the same batch obtained under the same process conditions are 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.

[0080] 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 the same parameters in theory.

[0081] 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 part for shear force test, and the remaining welding samples in each part are treated as good welding products for subsequent inspection.

[0082] 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.

[0083] 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.

[0084] Please refer to Figure 2 , Figure 2 Schematic diagram of good welding products provided for some embodiments of the present application. During the battery manufacturing process, the pole tab 2 and the adapter 3 are connected through a welding joint 4, wherein the pole tab 2 is connected to the battery cell 1, and the connection of the welding joint 4 is one of the structures of the battery assembly. Under normal circumstances, the pole tab 2 and the adapter 3 are tightly connected by welding to form a relatively stable welding joint 4, which can effectively transfer current when the battery is working.

[0085] The welding quality evaluation of the welding joint 4 (i.e. the aforementioned good product evaluation index) generally relies on the following two indicators: shear force and weld mark residual area. The shear force refers to the force required to directly shear the welding joint 4, and this value is an indicator for evaluating the strength of the welding joint 4.

[0086] Please refer to Figure 3-4 , Figure 3 Good welding products provided by some embodiments of the present application ( Figure 3Left half) and defective welding products ( Figure 3 During the welding process, a layer of weld mark area will be formed on the surface of the welding sample, that is, Figure 3 Area A and Area B in the. Figure 4 Some embodiments of the present application provide Figure 3 The enlarged schematic diagram of area A before and after shear force stretching. The residual weld rate is the ratio of the number of residual weld points c of the good weld product to the total number of weld points c of the good weld product after the good weld product is stretched under shear force, as shown in Figure 4 As shown in the figure, the total number of welds in the weld mark area is 27, and the number of residual welds c after stretching is 19. The weld mark residual area of ​​the weld joint = 19 / 27*100% = 70.4%, which is greater than 50%, that is, 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 welding, and the welding quality is high. If this ratio is lower, 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 standard.

[0087] By evaluating the welding quality between 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 between the battery tab and the adapter.

[0088] 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 borne by the good welding product; 0.5≤R≤1, R is the weld mark residual rate of the good welding product.

[0089] Generally speaking, the shear force satisfies 100N≤τ≤800N, which means 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.

[0090] like Figure 4 As shown in the figure, the total number of welds in the weld mark area is 27, and the number of residual welds c after stretching is 19. The weld mark residual area of ​​the weld joint = 19 / 27*100% = 70.4%, which is greater than 50%, that is, 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 welding, and the welding quality is high. If this ratio is lower, 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 standard.

[0091] Shear force and weld mark residual rate can be used to characterize the shear strength and welding quality in the welded structure, to evaluate the actual performance of the welding quality, and to better evaluate the welding quality of the battery tab and the adapter.

[0092] According to some embodiments of the present application, 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.

[0093] 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 print area is weakened, and the vibration speed is significantly increased.

[0094] 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 detected will appear abnormal.

[0095] The soldering rate of the weld mark area refers to the ratio of the soldering area in the weld mark area to the area of ​​the entire welding contact surface, i.e. the soldering area. The soldering rate directly affects the mechanical properties of the welded joint. Generally speaking, the higher the soldering rate, the greater the strength of the welded joint.

[0096] 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.

[0097] According to some embodiments of the present application, the characteristic parameter of the mode shape includes the aspect ratio of the mode shape.

[0098] The aspect ratio of the vibration shape can, to some extent, reflect the elastic characteristics and structural performance of the sample under test during vibration. When cracks appear in the weld joint, a stress concentration area will be formed, causing the stiffness of the local structure to change. During vibration, this change in stiffness will also cause changes in the vibration shape. Generally speaking, the more severe the crack, the greater the change in the aspect ratio of the vibration shape.

[0099] Please refer to Figure 5 , Figure 5 The vibration shape comparison diagram of good welding products and bad welding products provided in some embodiments of the present application. Figure 5 In the figure, W is the width of the vibration shape and H is the height of the vibration shape. Figure 5 The left half of is the vibration shape detection image of a good welding product. Figure 5 The right half is the vibration shape detection image of a defective weld. It can be seen that the aspect ratio (W / H) of the vibration shape of a defective weld is reduced to a certain extent compared to a good weld. 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 (and even the severity of the cracks).

[0100] It should be understood that the aspect ratio of the vibration shape is only an example of a characteristic parameter of the vibration shape. In other embodiments, other characteristic parameters of the vibration shape may be used as a judgment criterion, such as the area of ​​the vibration shape. Similar to the aspect ratio of the vibration shape, the area of ​​the vibration shape may also reflect the elastic characteristics and structural performance of the sample to be tested during vibration. Generally, the more severe the crack, the smaller the area of ​​the vibration shape.

[0101] 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 that the aspect ratio of the mode shape is smaller than the first threshold.

[0102] The aspect ratios of the vibration shapes of the plurality of good welding products can be obtained by measuring the vibration shapes of the plurality of good welding products at the resonance frequency, and the first threshold can be obtained based on the aspect ratios of the vibration shapes of the plurality of good welding products.

[0103] When a crack occurs in a weld joint, the vibrations on both sides of the crack tend to be discrete, and the vibration shape detected will appear abnormal. Therefore, when the aspect ratio of the vibration shape of the welded sample at the resonant frequency is less than the first threshold, the welded joint of the welded sample is cracked, and it is determined that the welded sample has a welding defect.

[0104] 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.

[0105] According to some embodiments of the present application, the corresponding threshold includes a second threshold for the vibration speed of the welding sample, and the criterion associated with the second threshold is that the vibration speed of the welding sample is greater than the second threshold.

[0106] The second threshold interval can be obtained based on the vibration speeds of the plurality of good welding products at the resonance frequency.

[0107] As the connection strength between the tab and the adapter plate decreases, the constraint of the adapter plate 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.

[0108] 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.

[0109] According to some embodiments of the present application, the corresponding threshold includes a third threshold for the soldering rate of the weld mark area, and the standard associated with the third threshold is: the soldering rate of the weld mark area is less than the third threshold.

[0110] The third threshold interval can be obtained based on the brazing rates of the plurality of good welds at the resonant frequency. Since the higher the brazing rate, the greater the strength of the weld joint. Therefore, when the brazing rate of the welded sample at the resonant frequency is less than the third threshold, the strength of the welded joint of the welded sample is insufficient, that is, it is determined that the welded sample has a welding defect.

[0111] By characterizing whether the soldering rate of the welding sample is less than the third threshold value, it is possible to quickly determine whether the connection strength of the welding joint of the welding sample reaches the preset standard, which can improve the detection accuracy and detection efficiency of the welding joint to a certain extent.

[0112] According to some embodiments of the present application, the welding sample includes a tab-to-transfer piece welding joint of a battery.

[0113] It should be understood that in such an embodiment, the good welding products used to measure the resonance frequency and the welding quality judgment threshold also include the battery's tab-adapter welding joint. That is, the resonance frequency and judgment threshold measured for the good welding tab-adapter welding joint will be applied to the welding quality detection of the tab-adapter welding joint of the welding sample.

[0114] By acquiring the vibration data of the battery's tab-adapter welding joint, it is possible to detect the welding quality of specific parts of the battery.

[0115] According to some embodiments of the present application, the resonant frequency of the tab-to-adapter plate welding joint is obtained by the following steps: driving the good tab-to-adapter plate welding 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 welding joint under the gradually changing excitation frequency by a vibration detector; and determining the excitation frequency corresponding to the good tab-to-adapter plate welding joint when the vibration speed is maximum as the resonant frequency of the tab-to-adapter plate welding joint.

[0116] A good tab-to-adapter welding joint is obtained by the following steps: obtaining a shear force test result of each of Y tab-to-adapter welding joints among X tab-to-adapter welding joints, wherein the X tab-to-adapter welding 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 welding joints satisfying a good product evaluation index, determining that the remaining XY tab-to-adapter welding joints among the X tab-to-adapter welding joints are at least one good tab-to-adapter welding joint. Due to the high consistency of battery cell manufacturing, the welding differences between the same batch of lug-adapter welding joints welded under the same process conditions are small. Therefore, a part of the same batch of lug-adapter welding joints welded under the same process conditions is selected for shear force testing. When the shear force test results of each lug-adapter welding joint meet the good product evaluation index, it is considered that the lug-adapter welding joints of this batch meet the requirements of good welding products, and the remaining XY lug-adapter welding joints that have not undergone shear force testing can be determined as good lug-adapter welding joints.

[0117] 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 resonance frequency of the tab-to-adapter welding joint.

[0118] 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.

[0119] Resonance frequency refers to the natural frequency at which an object or system can reach the maximum amplitude or vibration speed when driven by an external force. The following relationship is satisfied at resonance:

[0120]

[0121] 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 total force of the oscillator, m is the mass of the oscillator, f0 is the natural frequency of the good welding product, and f is the ultrasonic excitation frequency.

[0122] As a feasible implementation, the vibration generator may 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 effect of a medium. The vibration detector may be an acceleration sensor, a piezoelectric vibration sensor, or a laser vibrometer, which is not specifically limited here.

[0123] 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.

[0124] 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.

[0125] By setting a suitable frequency step, a more accurate resonance frequency can be found, thereby improving the accuracy of detection.

[0126] Please refer to Figure 6 , Figure 6 A structural schematic diagram of a welding quality detection system provided for some embodiments of the present application. The embodiments of the present application provide a welding quality detection system, comprising: a vibration generator 8, a vibration detector 7 and an industrial computer 11, wherein the industrial computer 11 comprises a memory storing instructions; and a processor, the processor being configured to execute instructions to perform operations, the operations comprising: 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 satisfying a standard associated with a corresponding threshold.

[0127] Please refer to Figure 7 , Figure 7 A block diagram of an industrial computer provided for some embodiments of the present application. The industrial computer 11 is intended to represent various forms of digital electronic computer devices, 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 merely examples.

[0128] like Figure 7 As shown, the industrial computer 11 includes a processor 111, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 112 or an instruction loaded from a storage unit 118 into a random access memory (RAM) 113. In the RAM 113, various programs and data required for the operation of the industrial computer 11 can also be stored. The computing unit 111, the ROM 112, and the RAM 113 are connected to each other via a bus 114. An input / output (I / O) interface 115 is also connected to the bus 114.

[0129] Multiple components in 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 that can input information to the industrial computer 11. The input unit 116 can receive input digital or character information, and generate key signal input related to user settings and / or function control of the electronic device, and can include but is not limited to a mouse, a keyboard, a touch screen, a track pad, a track ball, a joystick, a microphone, and / or a remote control. The output unit 117 can be any type of device that can present information, and can 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 can include but is not limited to a disk and an optical disk. The communication unit 119 allows the industrial computer 11 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks, and can include but is not limited to a modem, a network card, an infrared communication device, a wireless communication transceiver, and / or a chipset.

[0130] The processor 111 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 111 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 111 executes the various methods and processes described above, such as the welding quality detection method in the above embodiments.

[0131] A welding quality inspection system directly extracts the vibration parameters of welding samples at the resonant frequency for defect detection, and has the characteristics of high detection accuracy, convenience and efficiency. If the welding quality is not good, problems such as fracture or structural damage may occur. If the welding part can keep the various vibration parameters stable at the resonant frequency, it means that the welding quality is good. On the contrary, if the various vibration parameters meet the standards associated with the corresponding thresholds at the resonant frequency, it means that there may be problems at the welding part, which improves the detection rate and detection efficiency of welding defects to a certain extent.

[0132] Continue to refer Figure 6 According to some embodiments of the present application, a welding quality inspection system further includes a vibration isolation platform 5, and the vibration isolation platform 5 is used to support the welding sample during the period when the welding sample vibrates at a resonant frequency.

[0133] The vibration isolation platform 5 can isolate and control the vibration interference of the external environment on the welding sample during the vibration test, so as to improve the accuracy of the test. As a feasible implementation, the vibration isolation platform 5 can be an air-floating vibration isolation platform, which isolates the platform from its bracket through air springs to isolate external vibrations.

[0134] The vibration isolation platform 5 can isolate the interference of environmental vibration and improve the stability and accuracy of measurement.

[0135] 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.

[0136] A vibration generator is a device that creates 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.

[0137] The vibration wave generated by the vibration generator generally propagates in the same direction as the vibration direction of the vibration sound generator, so the vibration direction of the vibration generator determines the original propagation direction of the vibration wave.

[0138] The sharp angle of incidence on the welding sample can reduce the measurement error and improve the accuracy of the detection. At the same time, the sharp angle of incidence can make the vibration path longer, so more accurate measurement results can be obtained.

[0139] According to some embodiments of the present application, the acute angle θ satisfies: 40°≤θ≤60°.

[0140] The welding sample is incident at an angle of 40°-60°, which can reduce the measurement error and improve the accuracy of the detection. At the same time, the vibration path can be longer at an angle of 40°-60°, so more accurate measurement results can be obtained.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] The ultrasonic transducer 8 is used to convert the voltage signal into ultrasonic waves and project them onto the weld joint. The ultrasonic transducer 8 can provide very precise and consistent power and can well control the frequency and amplitude of the vibration. Compared with other types of vibration generators, the ultrasonic transducer 8 has a higher energy conversion efficiency, is small in size, easy to install and maintain, has a fast response speed, and can generate strong vibrations in a short time.

[0146] 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. Therefore, the ultrasonic transducer 8 can improve the measurement stability and detection efficiency to a certain extent.

[0147] 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.

[0148] The signal generator 10 and the power amplifier 9 are often used in pairs. The signal generator 10 generates the required voltage signal, and then the power amplifier 9 further amplifies the signal so that the excitation signal has enough energy to drive subsequent devices to perform specific operations.

[0149] According to some embodiments of the present application, the welding sample includes a tab-to-transfer piece welding joint of a battery.

[0150] refer to Figure 2 , when the welded good product includes the battery cell 1, the tab 2, the adapter 3 and the weld joint 4, the welded sample also includes the battery cell, the tab, the adapter and the weld joint. The welded sample and welded good product corresponding to the same welding position to be tested should be based on the same reference.

[0151] By acquiring the vibration data of the battery's tab-adapter welding joint, it is possible to detect the welding quality of specific parts of the battery.

[0152] It should be understood that the tab-adapter welding joint is only an example, and in other embodiments, the welding quality can be tested for other appropriate welding positions of the battery.

[0153] Please refer to Figure 8 , Figure 8 A schematic diagram of the structure of a welding quality detection device provided in some embodiments of the present application. The present application embodiment provides a welding quality detection device 800, including:

[0154] The first module 801 is used to obtain vibration data of a 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.

[0155] The second module 802 is used to determine at least one vibration parameter of the welding sample based on the vibration data.

[0156] The third module 803 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 parameter satisfying a criterion associated with a corresponding threshold.

[0157] Since the first module 801, the second module 802 and the third module 803 in the welding quality detection device 800 can correspond to Figure 1 Therefore, the details of each aspect thereof will not be repeated here.

[0158] 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 performs an action including the specific module itself performing the action, or alternatively the specific module calls or otherwise accesses 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.

[0159] It should also be understood that various techniques may be described herein in the general context of software hardware elements or program modules. Figure 8 The modules described can be implemented in hardware or in hardware in combination 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 (e.g., central processing units (CPU), microcontrollers, microprocessors, digital signal processors (DSP), etc.), memory, one or more communication interfaces, and / or one or more components in other circuits), and can optionally execute the received program code and / or include embedded firmware to perform functions.

[0160] An embodiment of the present application also provides a computer-readable storage medium on which instructions are stored. When the instructions are executed by a processor, the processor executes the welding quality detection method in any of the above embodiments.

[0161] 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 device, magnetic cassette, magnetic tape, magnetic disk storage device or other magnetic storage device, or any other non-transmission medium that can be used to store information for access by a computer device. In contrast, communication media can embody 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 do not include communication media.

[0162] The present application also provides a computer program product, including instructions, which, when executed by a processor, cause the processor to execute the welding quality detection method in any of the above embodiments. Such a computer program or instruction has been described above. Figure 7 For the sake of brevity, it is not repeated here.

[0163] According to some embodiments of the present application, Figure 1-6 As shown, the embodiment of the present application provides a welding quality detection method, including:

[0164] Vibration data of a welding sample detected by a scanning laser vibrometer lens at a resonant frequency 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; in response to at least one of the above at least one vibration parameter satisfying a standard associated with a corresponding threshold value, it is determined that the welding sample has a welding defect.

[0165] Before measuring the welding sample, the 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.

[0166] 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.

[0167] As a feasible implementation method, a total of 420 good welding products were selected, and the 420 good welding products were classified according to the copper tab-adapter welding joint and the aluminum tab-adapter welding joint, and placed in batches on the air-floating vibration isolation platform. The ultrasonic transducer excitation frequency drives each batch of good welding products to vibrate, the excitation frequency range meets 20-800kHz, the frequency interval is 1-5kHz, the ultrasonic incident angle is 40-60°, and the scanning laser vibration lens is used to detect the sample vibration signal at a distance of about 20-50mm from the good welding product. As a feasible implementation method, the excitation frequency range meets 20-800kHz, the frequency interval is 2kHz, the ultrasonic incident angle is 45°, and the scanning laser vibration lens is used to detect the sample vibration signal at a distance of about 40mm from the good welding product. The average resonance frequency of the good welding of the copper tab-adapter welding joint is 301kHz, and the average resonance frequency of the good welding of the aluminum tab-adapter welding joint is 165kHz.

[0168] The excitation frequency of the ultrasonic transducer is set to the resonant frequency corresponding to the good welding product, and the vibration parameters of multiple good welding products at the resonant frequency are measured respectively, and the first threshold value Th1=W / H≥0.8 is obtained based on the aspect ratio of the vibration shape of multiple good welding products, where W is the width of the vibration shape and H is the height of the vibration shape. The vibration speed of multiple good welding products at the resonant frequency is measured, and the vibration speeds of both are less than 1E-05m / s, that is, the second threshold value is Th2≤1E-05m / s. The soldering rate of multiple good welding products at the resonant frequency is measured, and the soldering rate of both meets the third threshold value Th3≥0.5.

[0169] The excitation frequency of the ultrasonic transducer is maintained at the resonant frequency corresponding to good welding products, 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.

[0170] 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 replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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, characterized in that: include: 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, characterized in that 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, characterized in that: 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, characterized in that: 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, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that The characteristic parameter of the mode shape includes an aspect ratio of the mode shape.

9. The method according to claim 8, characterized in that 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, characterized in that: 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, characterized in that: 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, characterized in that The welding sample includes a battery tab-adapter welding joint.

13. The method according to claim 12, characterized in that 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, characterized in that 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, characterized in that 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, characterized in that: include: 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, characterized in that: 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, characterized in that: 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, characterized in that: The acute angle θ satisfies: 40°≤θ≤60°.

20. The welding quality inspection system according to any one of claims 16 to 19, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: The welding sample includes a battery tab-adapter welding joint.

24. A welding quality detection device, characterized in that: include: 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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