A method, system and terminal for detecting defects in finished battery products

Abstract

This application relates to a method, system, and terminal for detecting defects in finished batteries, belonging to the technical field of battery detection. The method comprises: performing laser interferometric scanning along the corners of the top seal of the finished battery pack, using a spiral scanning method; acquiring scanning data during the spiral scanning process, the scanning data including fringe spacing and contrast; determining whether the fringe spacing is not less than 1.2 times the normal fringe spacing value and whether the contrast is lower than the normal contrast value; and if so, marking the scanning area corresponding to the current fringe spacing as a preliminary leakage area. This application has the beneficial effect of improving the safety of finished batteries after they leave the factory.

Description

Technical Field

[0001] The present application relates to the technical field of battery detection, and in particular to a method, system, and terminal for detecting defects in finished battery products. Background Art

[0002] Currently, technology for defect detection in finished batteries has made considerable progress. For example, in the area of ​​visual defect detection for soft-pack batteries (such as lithium batteries), systems using machine vision technology are now available to inspect multiple surfaces of lithium batteries. These systems can simultaneously inspect all six surfaces of the battery, improving inspection efficiency. During the battery electrode preparation process, an increasing number of online inspection technologies are being used, such as slurry property testing, electrode quality testing, and dimensional testing, to effectively identify manufacturing defects.

[0003] However, in practice, it is found that although the finished batteries pass the traditional air tightness test before leaving the factory, there are still customers reporting that some battery packs have electrolyte leakage after transportation, resulting in a major safety hazard for the finished batteries after leaving the factory. Summary of the Invention

[0004] In order to improve the safety of finished battery products after leaving the factory, the present application provides a method, system and terminal for detecting defects in finished batteries.

[0005] In a first aspect, the present application provides a method for detecting defects in finished battery products, which adopts the following technical solutions:

[0006] A method for detecting defects in finished battery products, comprising:

[0007] Laser interference scanning is performed along the corners of the top seal of the finished battery pack, using a spiral scanning method;

[0008] Acquiring scanning data during the spiral scanning process, wherein the scanning data includes fringe spacing and contrast;

[0009] Determine whether the fringe spacing is not less than 1.2 times the normal fringe spacing value and whether the contrast is lower than the normal contrast value;

[0010] If so, the scanning area corresponding to the current fringe spacing is marked as the preliminary leakage area.

[0011] By adopting the above technical solution, laser interference scanning uses the principle of light wave interference to perform a spiral scan on the top seal side corners of the finished battery. The fringe spacing and contrast are obtained as scanning data. When the fringe spacing is not less than 1.2 times the normal fringe spacing value and the current contrast is lower than the normal contrast value, the area is marked as a preliminary leakage area. This judgment method based on precise optical feature changes can keenly capture the subtle physical changes caused by leakage in the top seal side corners of the battery. Even extremely subtle leakage can be detected, greatly improving the accuracy of leakage detection. The spiral scanning method is used to scan the top seal side corners of the finished battery. This scanning method can achieve full coverage of the area and avoid the detection blind spots that may exist in traditional scanning methods. The spiral scanning path can ensure that every part of the top seal side corner can be scanned by the laser, making the detection more comprehensive and able to discover leakage defects hidden in various locations, thereby improving the safety of the finished battery after leaving the factory.

[0012] Optionally, the step of obtaining the stripe spacing includes:

[0013] Get the detection duration of the current judgment moment;

[0014] Inputting the detection duration into a pre-built incident angle model to obtain a current incident angle of the spiral scan;

[0015] Obtaining a current fringe spacing according to the current incident angle and the laser wavelength of the laser interference scanning;

[0016] The incident angle model is , is the rotation speed of spiral scanning, t is the detection time, is the current incident angle; the current fringe spacing , is the laser wavelength.

[0017] By employing the above technical solution, by obtaining the detection duration at the current judgment moment and inputting it into a pre-built incident angle model, the specific position and state of the spiral scan at the top and side corners of the battery pack can be accurately determined. Since the incident angle varies over time during the spiral scan process and has a significant impact on the fringe spacing, incorporating time into the determination of the incident angle and subsequent calculation of the fringe spacing ensures that the detection results more accurately reflect the current actual battery state, avoiding detection errors caused by not considering changes in scanning time and incident angle, thereby improving the accuracy of defect detection in finished batteries. After obtaining the current incident angle, the fringe spacing is calculated based on the wavelength of the laser used in the laser interferometer scan. Lasers have a fixed and known wavelength, which is a precise physical parameter. Calculating based on the incident angle and laser wavelength leverages the precision of the interference principle of light, making the fringe spacing calculation more scientific and accurate. Accurate fringe spacing is key to determining whether a battery has defects such as leakage. Therefore, this step improves the reliability of the detection results and helps to more accurately detect defects in finished batteries.

[0018] Optionally, the step after marking the area corresponding to the current stripe spacing as the preliminary leakage area includes:

[0019] Obtaining a monitoring area of ​​the preliminary leakage area;

[0020] applying a gradient negative pressure to the preliminary leakage area;

[0021] Obtaining the maximum displacement of the speckle in the preliminary leakage area;

[0022] Obtaining the duration of the negative pressure applied corresponding to the maximum displacement;

[0023] Obtaining a leakage rate according to the monitoring area and the duration;

[0024] determining whether the leakage rate is less than a leakage rate threshold;

[0025] If not, it is determined that the preliminary leakage area mark is valid;

[0026] The leak rate ,in, is the maximum displacement, is the monitoring area, is the electrolyte density, is the material deformation coefficient of the finished battery, For duration.

[0027] By employing the above technical solution, after marking the preliminary leak area, multiple leak-related factors are comprehensively considered through steps such as determining the monitoring area of ​​the preliminary leak area, applying a gradient negative pressure, and determining the maximum speckle pattern displacement and the corresponding duration of the negative pressure. These parameters reflect the initial leak area from different perspectives. For example, the monitoring area reflects the extent of the leak, while the maximum speckle pattern displacement and the duration of the negative pressure are related to the dynamic process of the leak. Finally, the leak rate is calculated based on the monitoring area and duration and compared with the leak rate threshold. This multi-parameter comprehensive assessment method can more comprehensively and accurately determine whether the preliminary leak area is leaking, compared to single-factor judgment, significantly improving the accuracy of leak judgment. If the leak rate is less than the leak rate threshold, it indicates that the area is likely not a true leak area, effectively eliminating false positives and ensuring the final leak area marking is reliable. By rigorously evaluating and processing the preliminary leak area, batteries with quality issues can be screened out and prevented from entering the market, thereby improving the quality and reliability of battery products and further strengthening user trust.

[0028] Optionally, the steps after determining that the preliminary leakage area mark is valid include:

[0029] locally heating the initial leakage area and reapplying gradient negative pressure;

[0030] Get a new leak rate;

[0031] Determining whether the increase rate of the new leakage rate exceeds an increase rate threshold;

[0032] If so, the preliminary leakage area is marked as the real leakage area.

[0033] By adopting the above technical solution, after determining that the preliminary leakage area mark is valid, the area is locally heated and gradient negative pressure is re-applied. Heating will change the physical properties of the liquid, such as reducing the viscosity of the liquid and increasing its fluidity; gradient negative pressure will promote liquid leakage. By combining the two factors of heat and pressure, potential leakage can be more obviously stimulated. If there is indeed leakage in the area, the leakage will be more obvious under such conditions, making it easier to more accurately determine whether it is a real leakage area, reduce the possibility of misjudgment, and improve the accuracy of detection. When the increase rate exceeds the threshold, it means that under the action of heating and negative pressure, the liquid leakage situation has been significantly aggravated, which strongly proves that there is indeed a leakage problem in the preliminary leakage area, and thus it is marked as a real leakage area.

[0034] Optionally, after determining whether the increase rate of the new leakage rate exceeds the increase rate threshold, the step further includes:

[0035] If not, applying a pulse sequence to the preliminary leakage area;

[0036] Get the pressure difference change rate;

[0037] Determining whether the pressure difference change rate exceeds a standard;

[0038] If so, start the ultrasonic wave to dredge the blockage;

[0039] After ultrasonic dredging, obtain the leakage rate after dredging;

[0040] Determining whether the increase rate of the leakage rate after dredging exceeds 2 times the increase rate threshold;

[0041] If so, the preliminary leakage area is marked as the real leakage area.

[0042] By employing the above technical solution, when the new leakage rate increase does not exceed the increase rate threshold, a pulse sequence is applied to the initial leakage area. The pressure fluctuations generated by the pulse sequence can penetrate deeper into channels or gaps where leakage may exist. Some potential tiny leak points may not be fully stimulated during conventional testing. However, the dynamic pressure changes caused by the pulse sequence can cause the liquid in these tiny leak points to move and leak, thereby exposing previously hidden leaks and improving the comprehensiveness and accuracy of leak detection. The pressure differential change rate is then measured and determined to determine whether it exceeds the standard. The pressure differential change rate is a key indicator of the flow characteristics of the liquid in the leak channel. If the pressure differential change rate exceeds the standard, it indicates that the pressure within the leak area is changing abnormally under the action of the pulse sequence, indicating the possibility of actual leakage. This judgment method based on the pressure differential change rate is more accurate and can capture subtle leak characteristics, avoiding missing the actual leak area. When the pressure differential change rate exceeds the standard, ultrasonic unblocking is activated. In the initial leakage area of ​​the battery, impurities or small particles may be blocking the leakage channel, preventing the actual leakage from being revealed. Ultrasonic waves have a powerful cavitation effect and mechanical vibration, which can effectively remove these blockages and restore the smooth flow of leakage channels. By unblocking blocked channels, liquids can leak more smoothly, thereby more accurately reflecting the true situation of the leakage. After ultrasonic unblocking, the leakage rate after unblocking is obtained, and it is determined whether its increase rate exceeds the 2-fold increase rate threshold. If it exceeds the threshold, it means that the leakage situation has significantly worsened after unblocking, further confirming that the preliminary leakage area does have a leakage problem, and it is marked as a real leakage area. This method of comparative judgment before and after unblocking can eliminate detection errors caused by blockages and ensure that the final marked real leakage area is accurate.

[0043] Optionally, the step of determining whether the leakage rate is less than a leakage rate threshold further includes:

[0044] If so, the preliminary leakage area is marked as an artifact, and the radius of the spiral scan is increased.

[0045] By adopting the above technical solution, when the leakage rate is judged to be less than the leakage rate threshold, the preliminary leakage area is marked as an artifact. During the battery detection process, due to interference from various factors, such as ambient light, minor defects on the battery surface, etc., the laser interferometer scan may be misjudged, and areas that are not leaking may be marked as preliminary leakage areas. By judging the leakage rate, these artifact areas can be identified to avoid misjudging them as real leakage areas, thereby improving the accuracy of the detection results and ensuring that subsequent treatment measures are targeted at areas where there are real problems. Marking the artifact areas can avoid unnecessary subsequent testing and processing of these areas, reducing the waste of time and resources during the detection process. For example, further local heating of the artifact area, application of pulse sequences, etc. are avoided, reducing detection costs and improving detection efficiency. After marking the preliminary leakage area as an artifact, the radius of the spiral scan is increased. This means that the range of the laser interferometer scan is expanded, and areas with larger angles on the top seal of the battery pack can be detected. Some leakage areas that may have been undetected due to a small scanning range have a greater chance of being discovered after the scanning radius is expanded, thereby improving the comprehensiveness of leakage detection and the probability of leak discovery.

[0046] Optionally, the step of starting ultrasound to dredge includes:

[0047] Obtaining power density according to the pressure difference change rate and the monitoring area;

[0048] Obtaining ultrasonic starting power according to the power density;

[0049] Obtaining ultrasonic activation duration according to the pressure difference change rate, the monitoring area, and ultrasonic activation frequency;

[0050] Starting ultrasonic waves to dredge the blockage according to the starting power and the starting time;

[0051] The power density , is the blockage type coefficient, is the pressure difference change rate; the starting power ; The startup duration , is the starting frequency.

[0052] By employing the above technical solution, the power density is calculated based on the pressure differential change rate and the monitored area, which is then used to determine the ultrasonic starting power. The pressure differential change rate reflects the severity of the pressure fluctuation within the initial leak area, while the monitored area reflects the size of the leak. Different combinations of pressure differential change rate and monitored area indicate different levels of blockage and extent of the leak channel. By comprehensively considering these two factors to determine the power density and, consequently, the appropriate starting power, the ultrasonic energy output can be precisely matched to the actual leak area. For example, areas with a large pressure differential change rate and a large monitored area indicate severe and widespread blockage. In this case, a higher power density and starting power are obtained, ensuring sufficient ultrasonic energy to clear the blockage. In contrast, areas with a small pressure differential change rate and a small monitored area have a correspondingly lower power density to avoid energy waste and unnecessary damage to the battery, thereby achieving precise and effective unblocking. The ultrasonic start-up duration is determined based on the pressure differential change rate, the monitored area, and the ultrasonic start-up frequency. The starting frequency determines the ultrasonic vibration characteristics, while the pressure differential change rate and the monitored area reflect the extent and extent of the blockage. By combining these three factors to calculate the start-up duration, the ultrasonic wave can reach the leak area within the appropriate time. If the startup time is too short, the blockage may not be completely cleared; if the startup time is too long, energy will be wasted and may have adverse effects on the battery. Scientifically calculating the startup time makes the ultrasonic dredging process more reasonable and efficient, improving the dredging effect. By accurately determining the startup power and startup time, it is possible to avoid excessive effects of ultrasound on the battery. Excessive ultrasonic energy or prolonged action time may damage the internal structure and materials of the battery, affecting the battery's performance and life. The parameters in this step are accurately calculated based on actual conditions to ensure that the ultrasound will not cause additional damage to the battery while clearing the blockage, thereby protecting the battery's performance and safety to the greatest extent.

[0053] In a second aspect, the present application provides a battery product defect detection system, which adopts the following technical solutions:

[0054] A battery product defect detection system, comprising:

[0055] The scanning module is used to perform laser interference scanning along the corners of the top seal of the finished battery pack, using a spiral scanning method;

[0056] A data acquisition module, configured to acquire scanning data during the spiral scanning process, wherein the scanning data includes fringe spacing and contrast;

[0057] A judgment module, used to judge whether the stripe spacing is not less than 1.2 times the normal stripe spacing value and whether the contrast is lower than the normal contrast value;

[0058] The marking module is used to mark the scanning area corresponding to the current stripe spacing as a preliminary leakage area when the judgment module determines that the scanning area is yes.

[0059] In a third aspect, the present application provides a terminal that adopts the following technical solution:

[0060] A terminal, comprising:

[0061] a memory storing a battery product defect detection program;

[0062] The processor is used to execute the program stored in the memory to implement the steps of the above-mentioned battery product defect detection method.

[0063] In summary, this application has at least the following beneficial effects:

[0064] Laser interferometry scanning uses the principle of light wave interference to perform a spiral scan of the top seal corners of finished batteries. The fringe spacing and contrast are acquired as scanning data. When the fringe spacing is no less than 1.2 times the normal fringe spacing value and the current contrast is lower than the normal contrast value, the area is marked as a preliminary leakage area. This judgment method based on precise optical feature changes can keenly capture the subtle physical changes in the top seal corners of the battery caused by leakage. Even extremely subtle leakage can be detected, greatly improving the accuracy of leakage detection. The top seal corners of finished batteries are scanned using a spiral scanning method. This scanning method can achieve full coverage of the area, avoiding the potential blind spots in traditional scanning methods. The spiral scanning path ensures that every part of the top seal corner can be scanned by the laser, making the inspection more comprehensive and able to discover leakage defects hidden in various locations, thereby improving the safety of finished batteries after leaving the factory. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a first flow chart of an embodiment of the method of the present application;

[0066] Figure 2 This is a second flow chart of the method embodiment of the present application;

[0067] Figure 3 This is a third flow chart of the method embodiment of the present application;

[0068] Figure 4 This is a fourth flow chart of the method embodiment of the present application;

[0069] Figure 5 This is a fifth flow chart of the method embodiment of the present application;

[0070] Figure 6 This is the sixth flow chart of the method embodiment of the present application. DETAILED DESCRIPTION

[0071] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the appended drawings of the embodiments of the present invention. Figure 1 -Attached Figure 6 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0072] The first embodiment of the present application discloses a method for detecting defects in finished battery products. Figure 1 As an embodiment of the method for detecting defects in finished battery products, the method for detecting defects in finished battery products may include S110-S150:

[0073] S110, performing laser interference scanning along the corners of the top seal of the finished battery pack, using a spiral scanning method;

[0074] S120, acquiring scanning data during the spiral scanning process, the scanning data including fringe spacing and contrast;

[0075] S130, determining whether the stripe spacing is not less than 1.2 times the normal stripe spacing value and whether the contrast is lower than the normal contrast value;

[0076] S140: If yes, mark the scanning area corresponding to the current stripe spacing as a preliminary leakage area.

[0077] S150, if not, return to S120.

[0078] Specifically, the finished battery pack refers to the finished battery pack or finished battery before leaving the factory. The spiral scan starts from the right corner of the top seal of the finished battery pack, and the coordinates of the starting point of the right corner of the top seal are (0,0); the parameters of the spiral scan can be set as the pitch , rotation speed n=2 turns / second, step speed v=50mm / s.

[0079] Reference Figure 2 The step of obtaining the stripe spacing may include S210-S230:

[0080] S210, obtaining the detection duration of the current judgment moment;

[0081] S220 , inputting the detection duration into a pre-built incident angle model to obtain a current incident angle of the spiral scan;

[0082] S230 , obtaining a current fringe spacing according to a current incident angle and a laser wavelength of laser interference scanning.

[0083] Specifically, the incident angle model is , is the rotation speed of spiral scanning, t is the detection time, is the current incident angle. Current fringe spacing , The laser beam can be a dual-frequency laser beam with a wavelength of Green Light, Red light and green light are used for surface deformation detection, and red light is used for coating penetration; power density ≤ 5mw / mm² to avoid material damage; fringe spacing calculation Actually .

[0084] Contrast , is the maximum value of the fringe light intensity, is the minimum value of the fringe light intensity; and It can be represented by the grayscale value of the image. For example, the intact area: Grayscale value, Gray value, then . Leakage area: Grayscale value, Gray value, then .

[0085] If the current stripe spacing , and the current contrast , then the area corresponding to the current stripe spacing is marked as the preliminary leakage area. is the normal value of the stripe spacing, for example ; is the normal contrast value, for example, 0.79. The coordinates of the leakage point in the preliminary leakage area are , , The starting radius is 0mm by default, starting from the top sealing side corner.

[0086] Reference Figure 3 The steps after marking the area corresponding to the current stripe spacing as the preliminary leakage area may include S310-S380:

[0087] S310, obtaining a monitoring area of ​​a preliminary leakage area;

[0088] S320, applying gradient negative pressure to the initial leakage area;

[0089] S330, obtaining the maximum displacement of the speckles in the preliminary leakage area;

[0090] S340, obtaining the duration of the negative pressure applied corresponding to the maximum displacement;

[0091] S350, obtaining the leakage rate according to the monitoring area and duration;

[0092] S360, determining whether the leakage rate is less than a leakage rate threshold;

[0093] S370, if not, determining that the preliminary leakage area mark is valid;

[0094] S380: If yes, mark the preliminary leakage area as an artifact and increase the radius of the spiral scan.

[0095] Specifically, an infrared thermal imager can be used. The system uses a wavelength band to capture temperature anomalies in the electrolyte volatilization area. The visible light camera is used to capture the surface topography. Image fusion algorithms (such as wavelet transform) are then used to generate a high-precision outline of the leakage area. Edge detection (for example, the Canny operator) is then used to calculate the leakage area, which is the initial monitoring area of ​​the leakage area. A gradient negative pressure can be applied using a piezoelectric ceramic micropump from -10 kPa (5 seconds) to -30 kPa (3 seconds) to -50 kPa (2 seconds). A high-speed camera is then used to capture the displacement during each negative pressure stage. After the gradient negative pressure is applied, the maximum displacement, the corresponding negative pressure stage, and the duration of that negative pressure stage are screened.

[0096] Leak rate ,in, is the maximum displacement, is the monitoring area, is the electrolyte density, The material deformation coefficient of the finished battery, such as 0.12 for aluminum-plastic film and 0.18 for steel container, For duration.

[0097] When the leakage rate is less than the leakage rate threshold, the preliminary leakage area is marked as an artifact and the radius of the spiral scan is increased. For example, if the radius of the current spiral scan is 3.4 mm, the spiral scan is expanded with the leakage point coordinates of the preliminary leakage area as the center, and the scanning radius is expanded to 8 mm, and subsequent spiral scanning operations are continued.

[0098] Reference Figure 4 and Figure 5 , the steps after determining that the preliminary leakage area mark is valid may include S410-S530:

[0099] S410, locally heating the initial leakage area and re-applying gradient negative pressure;

[0100] S420, obtaining a new leakage rate;

[0101] S430, determining whether the increase rate of the new leakage rate exceeds the increase rate threshold;

[0102] S440, if yes, marking the preliminary leakage area as the actual leakage area;

[0103] S450, if not, applying a pulse sequence to the preliminary leakage area;

[0104] S460, obtaining the pressure difference change rate;

[0105] S470, determining whether the pressure difference change rate exceeds the standard;

[0106] S480, if yes, start ultrasonic wave to clear the blockage;

[0107] S490, if not, marking the preliminary leakage area as an artifact and increasing the radius of the spiral scan;

[0108] S500, after ultrasonic dredging, obtaining the leakage rate after dredging;

[0109] S510, determining whether the increase rate of the leakage rate after dredging exceeds a 2-fold increase rate threshold;

[0110] S520, if yes, marking the preliminary leakage area as the actual leakage area;

[0111] If not, the preliminary leakage area is marked as an artifact and the radius of the spiral scan is increased.

[0112] Specifically, for example, the leak point is locally heated to 50° C., and then the above-mentioned gradient negative pressure is re-applied, and the new leakage rate is calculated. , , is the leakage rate calculated before heating, is the new leak rate calculated after heating.

[0113] The pulse sequence can be , frequency 5Hz, lasting 3 cycles. The pressure difference change rate is If the pressure difference change rate is much greater than the pressure difference change rate threshold (for example, greater than 3 times the pressure difference change rate threshold), it is determined that the pressure difference change rate exceeds the standard.

[0114] Reference Figure 6 The steps of starting ultrasonic wave to dredge may include S610-S640:

[0115] S610, obtaining power density according to the pressure difference change rate and the monitoring area;

[0116] S620, obtaining ultrasonic starting power according to the power density;

[0117] S630, obtaining the ultrasonic activation duration according to the pressure difference change rate, the monitoring area, and the ultrasonic activation frequency;

[0118] S640, activates ultrasonic wave to dredge the blockage according to the starting power and starting time.

[0119] Specifically, the power density , is the blockage type coefficient; is the pressure difference change rate; starting power ; Startup time , is the starting frequency. It should be noted that if the calculated Greater than , then the actual power density is .

[0120] There is a quantitative relationship between the pressure difference change rate and the characteristics of the blockage: if the pressure difference change rate is >5kPa / s, it means that the blockage is caused by large particles (such as metal debris, colloidal agglomerates), and the corresponding is 0.35; if the pressure difference change rate is , it means colloid / microorganism adhesion blockage, the corresponding is 0.28; if the pressure difference change rate is <2kPa / s, it means that the electrolyte crystallizes and deposits, and the corresponding is 0.15.

[0121] In addition, the determination of the starting frequency is related to the monitoring area. The starting frequency is selected from the range of 28KHz-120KHz according to the A value; for example, the monitoring area , low frequency (28KHz-40KHz) can be used for wide area coverage cleaning; monitoring area , high frequency (80KHz-120KHz) can be used for micropore penetration cleaning.

[0122] After the ultrasonic unclogging is completed, the leakage rate after unclogging is calculated. If the increase rate of the leakage rate after unclogging exceeds the 2-fold increase rate threshold, the preliminary leakage area is marked as the real leakage area, which means that the finished battery pack is indeed leaking.

[0123] The implementation of this embodiment is as follows:

[0124] Before the finished battery pack leaves the factory, a spiral scan is performed along the side corners of the top seal of the finished battery pack, and then the fringe spacing and contrast during the spiral scanning process are obtained; and it is determined whether the fringe spacing is not less than 1.2 times the normal value of the fringe spacing and whether the contrast is lower than the normal value of the contrast; if so, the scanning area corresponding to the current fringe spacing and the current contrast is marked as the preliminary leakage area; then the monitoring area of ​​the preliminary leakage area is obtained, and a gradient negative pressure is applied to the preliminary leakage area; the maximum displacement of the speckle in the preliminary leakage area is obtained, and the duration of the negative pressure applied corresponding to the maximum displacement is determined, and combined with the monitoring area, the leakage rate is calculated, and it is determined whether the leakage rate is less than the leakage rate threshold; if not, the preliminary leakage area mark is determined to be valid, and then the preliminary leakage area is locally heated, and the gradient negative pressure is reapplied, and then the new leakage rate is obtained, and it is determined whether the increase rate of the new leakage rate exceeds the increase rate threshold. If so, the preliminary leakage area is marked as the real leakage area.

[0125] Based on the above method embodiments, the second embodiment of the present application discloses a battery product defect detection system. The battery product defect detection system of the embodiment of the present application can implement any of the above battery product defect detection methods, and the specific working process of each module in the battery product defect detection system can refer to the corresponding process in the above method embodiments.

[0126] For ease of understanding, an example is given below: A battery product defect detection system includes:

[0127] The scanning module is used to perform laser interference scanning along the corners of the top seal of the finished battery pack, using a spiral scanning method;

[0128] A data acquisition module is used to acquire scanning data during the spiral scanning process, wherein the scanning data includes fringe spacing and contrast;

[0129] A judgment module, used to judge whether the stripe spacing is not less than 1.2 times the normal stripe spacing value and whether the contrast is lower than the normal contrast value;

[0130] The marking module is used to mark the scanning area corresponding to the current stripe spacing as a preliminary leakage area when the judgment module determines that the leakage is yes.

[0131] The third embodiment of the present application provides a terminal. As an implementation of the terminal, the terminal may include: a memory and a processor; wherein,

[0132] The memory is used to store a battery product defect detection program;

[0133] The processor is used to execute the program stored in the memory to implement the steps of the above-mentioned battery product defect detection method.

[0134] The memory may be communicatively connected to the processor via a communication bus, and the communication bus may be an address bus, a data bus, a control bus, or the like.

[0135] In addition, the memory may include a random access memory (RAM) and may also include a non-volatile memory (NVM), such as at least one disk storage.

[0136] The processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0137] The above are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Unless otherwise specified, any feature disclosed in this specification (including the abstract and drawings) may be replaced by other equivalent or similar features. In other words, unless otherwise specified, each feature is merely an example of a series of equivalent or similar features.

Claims

1. A method for detecting defects in finished battery products, characterized in that: include: Laser interference scanning is performed along the corners of the top seal of the finished battery pack, using a spiral scanning method; Acquiring scanning data during the spiral scanning process, wherein the scanning data includes fringe spacing and contrast; Determine whether the fringe spacing is not less than 1.2 times the normal fringe spacing value and whether the contrast is lower than the normal contrast value; If so, the scanning area corresponding to the current fringe spacing is marked as the preliminary leakage area; The steps after marking the area corresponding to the current stripe spacing as the preliminary leakage area include: Obtaining a monitoring area of ​​the preliminary leakage area; applying a gradient negative pressure to the preliminary leakage area; Obtaining the maximum displacement of the speckle in the preliminary leakage area; Obtaining the duration of the negative pressure applied corresponding to the maximum displacement; Obtaining a leakage rate according to the monitoring area and the duration; determining whether the leakage rate is less than a leakage rate threshold; If not, it is determined that the preliminary leakage area mark is valid; The leak rate ,in, is the maximum displacement, A is the monitoring area, is the electrolyte density, k is the material deformation coefficient of the finished battery, For duration.

2. A method for detecting defects in finished battery products according to claim 1, characterized in that: The step of obtaining the stripe spacing comprises: Get the detection duration of the current judgment moment; Inputting the detection duration into a pre-built incident angle model to obtain a current incident angle of the spiral scan; Obtaining a current fringe spacing according to the current incident angle and the laser wavelength of the laser interference scanning; The incident angle model is , n is the rotation speed of spiral scanning, t is the detection time, is the current incident angle; the current fringe spacing , is the laser wavelength.

3. The method for detecting defects in finished battery products according to claim 1, wherein: The steps after determining that the preliminary leakage area mark is valid include: locally heating the initial leakage area and reapplying gradient negative pressure; Get a new leak rate; Determining whether the increase rate of the new leakage rate exceeds an increase rate threshold; If so, the preliminary leakage area is marked as the real leakage area.

4. A method for detecting defects in finished battery products according to claim 3, characterized in that: After the step of determining whether the increase rate of the new leakage rate exceeds the increase rate threshold, the method further includes: If not, applying a pulse sequence to the preliminary leakage area; Get the pressure difference change rate; Determining whether the pressure difference change rate exceeds a standard; If so, start the ultrasonic wave to dredge the blockage; After ultrasonic dredging, obtain the leakage rate after dredging; Determining whether the increase rate of the leakage rate after dredging exceeds 2 times the increase rate threshold; If so, the preliminary leakage area is marked as the real leakage area.

5. The method for detecting defects in finished battery products according to claim 1, wherein: The step of determining whether the leakage rate is less than a leakage rate threshold further comprises: If so, the preliminary leakage area is marked as an artifact, and the radius of the spiral scan is increased.

6. A method for detecting defects in finished battery products according to claim 4, characterized in that: The step of starting ultrasonic wave to dredge comprises: Obtaining power density according to the pressure difference change rate and the monitoring area; Obtaining ultrasonic starting power according to the power density; Obtaining ultrasonic activation duration according to the pressure difference change rate, the monitoring area, and ultrasonic activation frequency; Starting ultrasonic waves to dredge the blockage according to the starting power and the starting time; The power density , is the blockage type coefficient, is the pressure difference change rate; the starting power ; The startup duration , f is the starting frequency.

7. A battery product defect detection system, characterized in that: The method for detecting defects in finished battery products according to any one of claims 1 to 6 is performed, wherein the system for detecting defects in finished battery products comprises: The scanning module is used to perform laser interference scanning along the corners of the top seal of the finished battery pack, using a spiral scanning method; A data acquisition module, configured to acquire scanning data during the spiral scanning process, wherein the scanning data includes fringe spacing and contrast; A judgment module, used to judge whether the stripe spacing is not less than 1.2 times the normal stripe spacing value and whether the contrast is lower than the normal contrast value; The marking module is used to mark the scanning area corresponding to the current stripe spacing as a preliminary leakage area when the judgment module determines that the scanning area is yes.

8. A terminal, characterized in that: include: A memory storing a battery product defect detection program; A processor is used to execute the program stored in the memory to implement the steps of the battery product defect detection method as described in any one of claims 1-6.

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