A method and apparatus for testing a chip aluminum electrolytic capacitor

Abstract

This invention discloses a testing method and apparatus for surface-mount aluminum electrolytic capacitors, belonging to the field of capacitor testing technology. The method includes: cleaning the pads to remove oxide layers and residual solder paste, obtaining pad cleanliness; determining the contact resistance threshold based on the rated equivalent series resistance, and constructing an Rc-pressure correspondence model to match the optimal contact pressure; clamping the sample and verifying that the contact resistance is less than or equal to the threshold; collecting initial capacitance, loss, and equivalent series resistance, and collecting leakage current after discharge; dynamically correcting parameters by calling a correction coefficient library in conjunction with temperature and humidity; performing single-parameter judgment and correlation verification on standard parameters, and outputting qualified / potentially failed / unqualified results. The apparatus includes pad cleaning pretreatment, contact resistance calibration, sample clamping and fixing, initial parameter acquisition and discharge, environmental adaptive correction, and qualification judgment modules. This invention improves testing accuracy and efficiency, reduces the false negative rate, and is suitable for surface-mount capacitor factory and incoming inspection.

Description

Technical Field

[0001] This invention relates to the field of capacitor testing technology, specifically to a testing method and apparatus for surface-mount aluminum electrolytic capacitors. Background Technology

[0002] Surface mount aluminum electrolytic capacitors, as core energy storage and filtering components in electronic devices, are widely used in consumer electronics, automotive electronics, and industrial control. Their performance directly determines the stability and lifespan of downstream circuits. These capacitors rely on SMT (Surface Mount Technology) packaging, and the "terminal board" mounted on the bottom must meet stringent dimensional accuracy and sealing requirements. Post-packaging testing is crucial for intercepting defective products and preventing circuit failures—it's necessary to verify core parameters such as capacitance, loss, and leakage current to ensure the capacitor meets the functional requirements of different scenarios. Therefore, establishing efficient and accurate testing methods is of great significance for industry production and quality control.

[0003] Existing testing methods and apparatuses for surface-mount aluminum electrolytic capacitors suffer from several drawbacks. Surface-mount capacitors lack external leads, and oxidation or residual solder paste on the pads can easily lead to poor contact, introducing parasitic resistance that interferes with the accuracy of parameters such as equivalent series resistance and leakage current. Furthermore, the influence of ambient temperature and humidity on these parameters is not considered, and the lack of a dynamic correction mechanism results in data drift under non-standard environments. Additionally, the absence of standardized clamping procedures means that improper adjustment of vacuum adsorption pressure and contact pressure can easily cause sample displacement, further reducing test repeatability and failing to meet the testing requirements of high-precision applications. Therefore, a testing method and apparatus for surface-mount aluminum electrolytic capacitors is needed to address these problems. Summary of the Invention

[0004] To address the aforementioned technical problems, this paper provides a testing method and apparatus for surface-mount aluminum electrolytic capacitors. This technical solution solves the problems of existing surface-mount aluminum electrolytic capacitor testing methods and apparatuses mentioned in the background art. Because surface-mount capacitors have no external leads, oxidation of the solder pads or residual solder paste can easily lead to poor contact, introducing parasitic resistance that interferes with the testing accuracy of parameters such as equivalent series resistance and leakage current. At the same time, the influence of ambient temperature and humidity on the parameters is not considered, and there is a lack of dynamic correction mechanism, resulting in data drift under non-standard environments. Furthermore, there is no standardized procedure during clamping, and improper adjustment of vacuum adsorption pressure and contact pressure can easily cause sample displacement, further reducing test repeatability and making it difficult to meet the testing requirements of high-precision application scenarios.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A test method for surface-mount aluminum electrolytic capacitors includes:

[0007] Clean the pads of surface-mount aluminum electrolytic capacitors to remove oxide layers and residual solder paste, and obtain the pad cleanliness.

[0008] Obtain the rated equivalent series resistance of the sample and determine the contact resistance threshold. Collect contact resistance data under different contact pressures, establish an Rc-pressure correspondence model, and match the optimal contact pressure.

[0009] The pretreated sample is placed in the patch test fixture, fixed by vacuum adsorption, and the contact pressure is adjusted to the optimal value to verify that the contact resistance is less than or equal to the preset threshold.

[0010] First, obtain the initial capacitance, initial loss, and initial equivalent series resistance of the sample. Then, complete the sample discharge and collect the initial stable leakage current.

[0011] The ambient temperature and humidity are collected in real time, and the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample are dynamically corrected by calling the correction coefficient library to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample.

[0012] The standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample are evaluated for single-parameter compliance. Then, the parameters that meet the preset parameter thresholds are evaluated for correlation verification, and the results of the evaluation are output as qualified, potentially failed, or unqualified.

[0013] In an optional embodiment, cleaning the pads of the surface-mount aluminum electrolytic capacitor to remove the oxide layer and residual solder paste, and obtaining pad cleanliness, specifically includes:

[0014] Obtain the model and specifications of the surface mount aluminum electrolytic capacitor, determine the length and width of the pads, and further determine the pad area;

[0015] Based on the pad area, determine the power and cleaning time of the ultrasonic cleaning tool;

[0016] Start the ultrasonic cleaning tool to clean the solder pads for the first time;

[0017] Obtain images of the pads after the first cleaning to further determine the area of ​​residual oxide layer on the pads;

[0018] The secondary cleaning assessment value is obtained based on the ratio of the residual area to the pad area.

[0019] Set a secondary cleaning assessment threshold and determine whether secondary cleaning is needed. If the secondary cleaning assessment value is greater than the secondary cleaning assessment threshold, perform secondary cleaning; if the secondary cleaning assessment value is less than or equal to the secondary cleaning assessment threshold, stop cleaning.

[0020] Determine the final cleaned pad image, and obtain the residual area ratio again to obtain the pad cleanliness.

[0021] If the cleanliness of the solder pads is greater than or equal to the solder pad cleanliness threshold, then the sample pretreatment is confirmed to be complete.

[0022] The formulas for calculating the power and cleaning time of the ultrasonic cleaning tool are as follows:

[0023]

[0024] In the formula, The power of the ultrasonic cleaning tool. For pad area, The cleaning time for ultrasonic cleaning tools. For cleaning power coefficient, This is the cleaning time coefficient;

[0025] The formula for calculating the cleanliness of the solder pads is:

[0026]

[0027] In the formula, For pad cleanliness, This represents the ratio of the residual area in the final cleaned pad image.

[0028] In an optional embodiment, the steps of obtaining the sample's rated equivalent series resistance, determining the contact resistance threshold, collecting contact resistance data under different contact pressures, establishing an Rc-pressure correspondence model, and matching the optimal contact pressure specifically include:

[0029] The contact resistance threshold is obtained based on the rated equivalent series resistance of the chip aluminum electrolytic capacitor.

[0030] The test range of contact pressure is determined by the contact resistance threshold.

[0031] Based on the test range of contact pressure, pressure points are selected according to a preset step interval, and the contact resistance corresponding to each pressure point is collected by a micro-ohmmeter to obtain pressure-contact resistance data.

[0032] Based on the pressure-contact resistance data, an Rc-pressure correspondence model is established;

[0033] The minimum pressure value that satisfies the contact pressure being less than or equal to the contact resistance threshold is determined using the Rc-pressure correspondence model, and is taken as the optimal contact pressure.

[0034] Based on the optimal contact pressure, adjust the pressure adjustment component of the patch test fixture, collect the real-time contact resistance again, obtain the first contact resistance, verify that the first contact resistance is less than or equal to the contact resistance threshold, and complete the contact resistance collaborative calibration.

[0035] The formula for the Rc-pressure correspondence model is as follows:

[0036]

[0037] In the formula, For contact resistance, To contact pressure, The slope is the fitted slope. This is the fitting intercept.

[0038] In an optional embodiment, the step of placing the pretreated sample into a patch test fixture, fixing it by vacuum adsorption, adjusting the contact pressure to an optimal value, and verifying that the contact resistance is less than or equal to a preset threshold specifically includes:

[0039] Based on the optimal contact pressure, obtain the drive current of the clamp pressure regulating component;

[0040] Based on the driving current, a control signal is output to the clamp pressure regulating component to adjust the initial contact pressure to the optimal contact pressure.

[0041] Obtain the vacuum adsorption system parameters of the fixture, preset the adsorption negative pressure threshold, start the vacuum adsorption device, and collect the real-time adsorption pressure;

[0042] Based on the judgment result that the real-time adsorption pressure is less than or equal to the adsorption negative pressure threshold, the sample is preliminarily fixed.

[0043] Obtain the image of the sample position after initial fixation, and determine the offset Δx and Δy between the sample center and the center of the fixture test position. If Δx ≤ 0.1 mm and Δy ≤ 0.1 mm, the position is deemed qualified; otherwise, the position of the adsorption platform is finely adjusted.

[0044] After obtaining the result of the position being deemed qualified, the real-time contact resistance is collected again to obtain the second contact resistance;

[0045] Based on the verification results that the second contact resistance is less than or equal to the contact resistance threshold, it is confirmed that the sample is clamped and fixed in one go.

[0046] The formula for calculating the driving current of the clamp pressure regulating component is as follows:

[0047]

[0048] In the formula, This is the pressure-to-current conversion factor. For driving current, The optimal contact pressure is [the pressure required to achieve this].

[0049] In an optional embodiment, obtaining the initial capacitance, initial loss, and initial equivalent series resistance of the sample specifically includes:

[0050] Determine the LCR test frequency based on the rated capacitance of the surface-mount aluminum electrolytic capacitor;

[0051] Set the test voltage according to the LCR test frequency;

[0052] Based on the LCR test frequency and test voltage, the initial impedance signal of the sample is acquired and decomposed to obtain the resistive and reactive components.

[0053] The initial capacitance is determined by the reactance component;

[0054] Based on the resistive component and the initial capacitance, combined with the test frequency LCR test frequency, the initial loss tanδ=R×2πfC is determined;

[0055] Based on the LCR test frequency, switch to ESR test mode to collect the real-time equivalent series resistance of the sample;

[0056] The difference between the real-time equivalent series resistance and the first contact resistance is used as the initial equivalent series resistance.

[0057] The formula for calculating the initial capacitance is as follows:

[0058]

[0059] In the formula, For the initial capacitance, This is the reactance component;

[0060] The formula for calculating the initial loss is:

[0061]

[0062] In the formula, For initial losses, For resistance components, This is the initial capacitance.

[0063] In an optional embodiment, the further completion of sample discharge and acquisition of initial stable leakage current specifically includes:

[0064] After the high-frequency LCR module test is completed, start the discharge module and set the discharge resistor;

[0065] Obtain the rated voltage of the sample and determine the discharge time threshold;

[0066] The operating time of the discharge module is controlled to be greater than or equal to the discharge time threshold, and the residual voltage of the sample after discharge is collected.

[0067] The discharge is confirmed to be complete when the residual voltage is less than or equal to 0.05 times the rated voltage;

[0068] Based on the sample's rated voltage, set the leakage current test voltage;

[0069] Based on the leakage current test voltage, the voltage is slowly applied through the leakage current module, and the stable leakage current is collected after the voltage is maintained for a preset duration.

[0070] Verify that the value of the stable leakage current is within the range of 0 to the rated value of the stable leakage current, thereby determining the initial stable leakage current.

[0071] In an optional embodiment, the real-time acquisition of ambient temperature and humidity, and the use of a correction coefficient library to dynamically correct the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample, to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample, specifically includes:

[0072] The temperature and humidity sensors integrated into the testing platform are used to collect real-time ambient temperature and real-time relative humidity.

[0073] By using a pre-built correction coefficient library, the temperature correction coefficient and humidity correction coefficient corresponding to the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current are obtained respectively.

[0074] Based on the real-time ambient temperature, the initial capacitance and its corresponding temperature correction coefficient, the initial capacitance is calibrated to obtain the standard capacitance.

[0075] Based on real-time ambient temperature, initial loss and its corresponding temperature correction coefficient, the corrected loss is obtained as the standard loss.

[0076] Based on the real-time ambient temperature, the initial equivalent series resistance and its corresponding temperature correction coefficient, the corrected standard equivalent series resistance is obtained.

[0077] Based on real-time relative humidity, initial stable leakage current and its corresponding humidity correction coefficient, the corrected standard stable leakage current is obtained.

[0078] In an optional embodiment, the single-parameter qualification determination of the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample specifically includes:

[0079] From the datasheet of the surface-mount aluminum electrolytic capacitor, obtain the single-parameter qualified thresholds for capacitance, loss, equivalent series resistance and stable leakage current in sequence.

[0080] Further determine the capacitance deviation threshold, loss threshold, equivalent series resistance threshold, and leakage current threshold;

[0081] Based on the corrected standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current, the capacitance deviation rate and the equivalent series resistance deviation rate are determined respectively.

[0082] Further determine whether the capacitance deviation rate is within the capacitance deviation threshold range, whether the standard loss is less than or equal to the loss threshold, whether the standard equivalent series resistance is within the equivalent series resistance threshold range, and whether the standard stable leakage current is less than or equal to the leakage current threshold, and simultaneously obtain the first judgment result of the single parameter.

[0083] Based on the first judgment result of the single parameter, the standard capacitance, standard loss, standard equivalent series resistance or standard stable leakage current with values ​​between the first single parameter threshold and the second single parameter threshold are selected, and the parameter types close to the threshold are recorded.

[0084] Based on the parameter type that is close to the threshold, the preset association threshold rule is invoked;

[0085] Based on the correlation threshold rule, verify whether the other three parameters meet the requirements;

[0086] If all individual parameters are qualified and the correlation verification is passed, the sample is deemed qualified.

[0087] If all individual parameters are qualified but the correlation verification fails, the sample is determined to be potentially faulty.

[0088] If any single parameter exceeds the threshold, the sample is deemed unqualified.

[0089] The second determination result of the single parameter is further recorded, and the sample status is marked based on the second determination result of the single parameter.

[0090] In an optional embodiment, the step of initiating correlation verification for parameters that meet preset parameter thresholds and outputting a judgment result of whether the sample is qualified, potentially failed, or unqualified specifically includes:

[0091] Based on the second judgment result of the single parameter, the samples are divided into three categories: qualified, potentially failed, and unqualified.

[0092] Obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of qualified samples, record the sample model, test time, environmental parameters, and contact resistance, and generate a single sample test report in tabular format.

[0093] Acquire the markings of potentially failed samples, output a retest prompt signal, and clarify the parameters that need to be retested and the reasons for the failure of the associated verification;

[0094] Obtain the parameter values ​​of potentially failed samples after retesting, repeat the dynamic correction and pass / fail determination process, and update the sample status;

[0095] Record the test reports and status of all samples, and generate a batch test summary report, including the number of qualified samples, the number of unqualified samples, the number of potential failures, and the statistical distribution of key parameters.

[0096] Furthermore, a testing device for surface-mount aluminum electrolytic capacitors is proposed to implement the testing method described in any of the above embodiments, comprising:

[0097] A pad cleaning pretreatment module is used to clean the pads of surface mount aluminum electrolytic capacitors, remove oxide layers and residual solder paste, and obtain the pad cleanliness.

[0098] The contact resistance calibration module is used to obtain the rated equivalent series resistance of the sample, determine the contact resistance threshold, collect contact resistance data under different contact pressures, establish an Rc-pressure correspondence model, and match the optimal contact pressure.

[0099] The sample clamping and fixing module is used to place the pretreated sample into the patch test fixture, fix it by vacuum adsorption, adjust the contact pressure to the optimal value, and verify that the contact resistance is less than or equal to a preset threshold.

[0100] The initial parameter acquisition and discharge module is used to first acquire the initial capacitance, initial loss, and initial equivalent series resistance of the sample, then complete the sample discharge, and acquire the initial stable leakage current.

[0101] An environmental adaptive correction module is used to collect ambient temperature and humidity in real time, and call the correction coefficient library to dynamically correct the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample, so as to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample.

[0102] The conformity determination module is used to perform single-parameter conformity determination on the standard capacitance, standard loss, standard equivalent series resistance and standard stable leakage current of the sample, and then initiate correlation verification for parameters that meet the preset parameter thresholds, and output the determination result of whether the sample is qualified, potentially failed or unqualified.

[0103] Compared with the prior art, the beneficial effects of the present invention are:

[0104] This solution proposes a testing method for surface-mount aluminum electrolytic capacitors. The method involves cleaning the capacitor pads twice to remove oxide layers and residual solder paste. After the first cleaning, the residual area ratio is used to assess whether a second cleaning is necessary. This ensures the pad surface is free of interfering impurities, providing a foundation for stable contact resistance and avoiding parameter testing deviations caused by pad contamination. The contact resistance threshold is determined by obtaining the sample's rated equivalent series resistance. Contact resistance data under different contact pressures are collected to establish an Rc-pressure correspondence model. The optimal contact pressure is matched and verified, achieving precise control of the contact resistance within the threshold. This reduces the interference of parasitic contact resistance on low-resistance / high-frequency parameters such as ESR and loss, improving the accuracy of core parameter testing.

[0105] This solution proposes a testing method for surface-mount aluminum electrolytic capacitors. The method involves placing a pre-treated sample into a surface-mount test fixture and fixing it using vacuum adsorption. Verifications are made to ensure the adsorption pressure is less than or equal to a negative pressure threshold, the contact pressure is adjusted to the optimal value, and the sample position offset is less than or equal to a preset threshold. A secondary verification of the contact resistance is also performed. This method achieves stable sample clamping without displacement, avoiding test data drift caused by loose clamping and ensuring test repeatability. The method first collects the initial capacitance, initial loss, and initial equivalent series resistance of the sample. Based on the rated capacitance, the LCR test frequency is determined and the impedance signal is decomposed. Then, the discharge module is activated, controlling the discharge time to be greater than or equal to a threshold and verifying that the residual voltage is ≤0.05 times the rated voltage. Finally, the initial stable leakage current is collected, eliminating the interference of the sample residual voltage on the leakage current test and ensuring the accuracy and reliability of the initial four-parameter data.

[0106] This solution proposes a testing method for surface-mount aluminum electrolytic capacitors. By real-time acquisition of ambient temperature and humidity, and by calling a calibration coefficient library, the initial capacitance, loss, ESR, and leakage current are dynamically corrected for temperature and humidity (e.g., capacitance is corrected based on temperature coefficient, and leakage current is corrected based on humidity coefficient). This eliminates the influence of non-standard environments (temperature and humidity deviating from standard values) on the parameters, ensuring consistency of test data under different environments. It eliminates the need for a constant temperature and humidity laboratory. By performing single-parameter pass / fail judgment on standard parameters (calculating the deviation rate based on the specification threshold), and initiating associated verification for parameters close to the threshold (e.g., verifying loss and ESR when leakage current is close to the threshold), and marking potentially failed samples for retesting, and generating single-sample and batch test reports, this method reduces the omission of multi-parameter linked failures, improves the reliability of sample screening, and provides traceable data support for the testing process. Attached Figure Description

[0107] Figure 1 This is a flowchart of a testing method for surface-mount aluminum electrolytic capacitors proposed in this invention;

[0108] Figure 2 This is a flowchart illustrating the process of obtaining pad cleanliness in this invention.

[0109] Figure 3 This is a flowchart illustrating the process of obtaining the optimal contact pressure in this invention.

[0110] Figure 4 This is a frame diagram of a surface-mount aluminum electrolytic capacitor testing device proposed in this invention. Detailed Implementation

[0111] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0112] Reference Figure 1 - Figure 4 As shown, a test method for surface-mount aluminum electrolytic capacitors includes:

[0113] Clean the pads of surface-mount aluminum electrolytic capacitors to remove oxide layers and residual solder paste, and obtain the pad cleanliness.

[0114] Obtain the rated equivalent series resistance of the sample and determine the contact resistance threshold. Collect contact resistance data under different contact pressures, establish an Rc-pressure correspondence model, and match the optimal contact pressure.

[0115] The pretreated sample is placed in the patch test fixture, fixed by vacuum adsorption, and the contact pressure is adjusted to the optimal value to verify that the contact resistance is less than or equal to the preset threshold.

[0116] First, obtain the initial capacitance, initial loss, and initial equivalent series resistance of the sample. Then, complete the sample discharge and collect the initial stable leakage current.

[0117] The ambient temperature and humidity are collected in real time, and the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample are dynamically corrected by calling the correction coefficient library to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample.

[0118] The standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample are evaluated for single-parameter compliance. Then, the parameters that meet the preset parameter thresholds are evaluated for correlation verification, and the results of the evaluation are output as qualified, potentially failed, or unqualified.

[0119] Furthermore, the pads of the surface-mount aluminum electrolytic capacitors are cleaned to remove oxide layers and residual solder paste, and the cleanliness of the pads is assessed. This specifically includes:

[0120] Obtain the model and specifications of the surface mount aluminum electrolytic capacitor, determine the length and width of the pads, and further determine the pad area;

[0121] Based on the pad area, determine the power and cleaning time of the ultrasonic cleaning tool;

[0122] Start the ultrasonic cleaning tool to clean the solder pads for the first time;

[0123] Obtain images of the pads after the first cleaning to further determine the area of ​​residual oxide layer on the pads;

[0124] The secondary cleaning assessment value is obtained based on the ratio of the residual area to the pad area.

[0125] Set a secondary cleaning assessment threshold and determine whether secondary cleaning is needed. If the secondary cleaning assessment value is greater than the secondary cleaning assessment threshold, perform secondary cleaning; if the secondary cleaning assessment value is less than or equal to the secondary cleaning assessment threshold, stop cleaning.

[0126] Determine the final cleaned pad image, and obtain the residual area ratio again to obtain the pad cleanliness.

[0127] Based on the criterion that the cleanliness of the solder pads K ≥ 95%, the sample pretreatment is confirmed to be complete.

[0128] The formulas for calculating the power and cleaning time of ultrasonic cleaning tools are as follows:

[0129]

[0130] In the formula, The power of the ultrasonic cleaning tool. For pad area, The cleaning time for ultrasonic cleaning tools. For cleaning power coefficient, This is the cleaning time coefficient;

[0131] The formula for calculating pad cleanliness is:

[0132]

[0133] In the formula, For pad cleanliness, This represents the ratio of the residual area in the final cleaned pad image.

[0134] Specifically, the secondary cleaning power P' = 1.1 × P, and the time t' = 1.2 × t. If the pad length L and width W are given, then the pad area S = L × W. The cleaning power coefficient ranges from 0.8 to 1.2 W / mm². The cleaning time coefficient ranges from 0.5 to 0.8 s / mm². The secondary cleaning evaluation threshold is 5%.

[0135] Furthermore, the rated equivalent series resistance of the sample is obtained, the contact resistance threshold is determined, contact resistance data under different contact pressures are collected, an Rc-pressure correspondence model is established, and the optimal contact pressure is matched. Specifically, this includes:

[0136] The contact resistance threshold is obtained based on the rated equivalent series resistance of the chip aluminum electrolytic capacitor.

[0137] The test range of contact pressure is determined by the contact resistance threshold.

[0138] Based on the test range of contact pressure, pressure points are selected according to a preset step interval, and the contact resistance corresponding to each pressure point is collected by a micro-ohmmeter to obtain pressure-contact resistance data.

[0139] Based on the pressure-contact resistance data, an Rc-pressure correspondence model is established;

[0140] The minimum pressure value that satisfies the contact pressure being less than or equal to the contact resistance threshold is determined using the Rc-pressure correspondence model, and is taken as the optimal contact pressure.

[0141] Based on the optimal contact pressure, adjust the pressure adjustment component of the patch test fixture, collect the real-time contact resistance again, obtain the first contact resistance, verify that the first contact resistance is less than or equal to the contact resistance threshold, and complete the contact resistance collaborative calibration.

[0142] The formula for the Rc-pressure model is as follows:

[0143]

[0144] In the formula, For contact resistance, To contact pressure, The slope is the fitted slope. This is the fitting intercept.

[0145] Where the contact resistance threshold R c 0 = 0.06 × rated equivalent series resistance, ensuring that the contribution of contact resistance to the ESR test error is ≤3%. Based on the contact resistance threshold R c 0. Determine the contact pressure test range Prange = [30g, 70g] (covering the effective pressure range of conventional patch fixtures). Based on the contact pressure test range Prange, select pressure points P1, P2, ..., Pn (n = (70-30) / 5+1 = 9 pressure points) in 5g increments. Collect the contact resistance Rn corresponding to each pressure point using a micro-ohmmeter. c 1. R c 2、…、R cBased on the collected pressure-contact resistance data, the expression formula of the Rc-pressure correspondence model is established using a linear fitting algorithm. Based on this model, the minimum pressure value satisfying that the contact pressure is less than or equal to the contact resistance threshold is calculated and taken as the optimal contact pressure Poptimal. Based on the optimal contact pressure Poptimal, the pressure adjustment component of the patch test fixture is adjusted, and the real-time contact resistance Rc is collected again. c Actual (first contact resistance), verify R c Real is less than or equal to R c 0, complete contact resistance co-calibration.

[0146] Furthermore, the pretreated sample is placed in a patch test fixture and fixed by vacuum adsorption. The contact pressure is adjusted to the optimal value, and the contact resistance is verified to be less than or equal to a preset threshold. Specifically, this includes:

[0147] Based on the optimal contact pressure, obtain the drive current of the clamp pressure regulating component;

[0148] Based on the driving current, a control signal is output to the clamp pressure regulating component to adjust the initial contact pressure to the optimal contact pressure.

[0149] Obtain the vacuum adsorption system parameters of the fixture, preset the adsorption negative pressure threshold, start the vacuum adsorption device, and collect the real-time adsorption pressure;

[0150] Based on the judgment result that the real-time adsorption pressure is less than or equal to the adsorption negative pressure threshold, the sample is preliminarily fixed.

[0151] Obtain the image of the sample position after initial fixation, and determine the offset Δx and Δy between the sample center and the center of the fixture test position. If Δx ≤ 0.1 mm and Δy ≤ 0.1 mm, the position is deemed qualified; otherwise, the position of the adsorption platform is finely adjusted.

[0152] After obtaining the result of the position being deemed qualified, the real-time contact resistance is collected again to obtain the second contact resistance;

[0153] Based on the verification results that the second contact resistance is less than or equal to the contact resistance threshold, it is confirmed that the sample is clamped and fixed in one go.

[0154] The formula for calculating the drive current of the clamp pressure regulating component is as follows:

[0155]

[0156] In the formula, This is the pressure-to-current conversion factor. For driving current, The optimal contact pressure is [the pressure required to achieve this].

[0157] Specifically, The pressure-to-current conversion coefficient ranges from 0.02 to 0.03 A / g. Based on the driving current, a control signal is output to the clamp pressure adjustment component to adjust the initial contact pressure to the optimal contact pressure, with an allowable error within ±5%. The vacuum adsorption system parameters of the clamp are obtained, with a preset adsorption negative pressure threshold of -60 kPa to ensure no sample displacement.

[0158] Furthermore, the initial capacitance, initial loss, and initial equivalent series resistance of the sample are obtained, specifically including:

[0159] Determine the LCR test frequency based on the rated capacitance of the surface-mount aluminum electrolytic capacitor;

[0160] Set the test voltage according to the LCR test frequency;

[0161] Based on the LCR test frequency and test voltage, the initial impedance signal of the sample is acquired and decomposed to obtain the resistive and reactive components.

[0162] The initial capacitance is determined by the reactance component;

[0163] The initial loss is determined based on the resistive component and the initial capacitance, combined with the test frequency (LCR test frequency).

[0164] Based on the LCR test frequency, switch to ESR test mode to collect the real-time equivalent series resistance of the sample;

[0165] The difference between the real-time equivalent series resistance and the first contact resistance is used as the initial equivalent series resistance.

[0166] The formula for calculating the initial capacitance is as follows:

[0167]

[0168] In the formula, For the initial capacitance, This is the reactance component;

[0169] The formula for calculating the initial loss is:

[0170]

[0171] In the formula, For initial losses, For resistance components, This is the initial capacitance.

[0172] Specifically, the LCR test frequency is determined based on the rated capacitance of the surface-mount aluminum electrolytic capacitor. The LCR test frequency is 1 kHz when the rated capacitance is less than or equal to 10 μF, and 100 kHz when the rated capacitance is less than 10 μF, to match the testing accuracy requirements of samples with different capacitance values. The initial equivalent series resistance needs to be verified to be within the range of 0.8 × ESR rating to 1.2 × ESR rating to ensure the validity of the acquired data.

[0173] Furthermore, the sample discharge is further completed, and the initial stable leakage current is collected, specifically including:

[0174] After the high-frequency LCR module test is completed, start the discharge module and set the discharge resistor;

[0175] Obtain the rated voltage of the sample and determine the discharge time threshold;

[0176] The operating time of the discharge module is controlled to be greater than or equal to the discharge time threshold, and the residual voltage of the sample after discharge is collected.

[0177] The discharge is confirmed to be complete when the residual voltage is less than or equal to 0.05 times the rated voltage;

[0178] Based on the sample's rated voltage, set the leakage current test voltage;

[0179] Based on the leakage current test voltage, the voltage is slowly applied through the leakage current module, and the stable leakage current is collected after the voltage is maintained for a preset duration.

[0180] Verify that the value of the stable leakage current is within the range of 0 to the rated value of the stable leakage current, thereby determining the initial stable leakage current.

[0181] Specifically, the discharge resistor Rdischarge is set to 1kΩ to prevent excessive discharge current from damaging the sample. The discharge time threshold tdischarge = 3 × Urated × Crated / Rdischarge, where Urated is the sample's rated voltage and Crated is the rated capacitance. The stable leakage current rated range ILrated = 0.01 × Crated × Urated + 1μA.

[0182] Furthermore, ambient temperature and humidity are collected in real time, and a calibration coefficient library is used to dynamically correct the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample, resulting in the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample, specifically including:

[0183] The temperature and humidity sensors integrated into the testing platform are used to collect real-time ambient temperature and real-time relative humidity.

[0184] By using a pre-built correction coefficient library, the temperature correction coefficient and humidity correction coefficient corresponding to the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current are obtained respectively.

[0185] Based on the real-time ambient temperature, the initial capacitance and its corresponding temperature correction coefficient, the initial capacitance is calibrated to obtain the standard capacitance.

[0186] Based on real-time ambient temperature, initial loss and its corresponding temperature correction coefficient, the corrected loss is obtained as the standard loss.

[0187] Based on the real-time ambient temperature, the initial equivalent series resistance and its corresponding temperature correction coefficient, the corrected standard equivalent series resistance is obtained.

[0188] Based on real-time relative humidity, initial stable leakage current and its corresponding humidity correction coefficient, the corrected standard stable leakage current is obtained.

[0189] Specifically, the standard capacitance = initial capacitance × [1 + b × (T - 25)] (25℃ is the standard temperature, and b is the temperature correction factor corresponding to the initial capacitance); the standard loss = initial loss × [1 + c × (T - 25)], where c is the temperature correction factor corresponding to the initial loss; the standard equivalent series resistance = initial equivalent series resistance × [1 + a × (T - 25)], where a is the temperature correction factor corresponding to the initial equivalent series resistance; and the standard stable leakage current = initial stable leakage current × [1 + d × (RH - 45)] (45%RH is the standard humidity, and d is the humidity correction factor corresponding to the initial stable leakage current). Then, the corrected values ​​of the four parameters (standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current) need to be used to replace the measured values ​​(initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current) for subsequent judgment.

[0190] Understandably, the pre-built calibration coefficient library is constructed around the "influence of environmental parameters (temperature and humidity) on the four parameters (capacitance, loss, equivalent series resistance ESR, and leakage current) of surface-mount aluminum electrolytic capacitors." Through a five-step process of "sample selection – experimental design – data acquisition – model fitting – verification and optimization," a directly callable "environmental parameter – calibration coefficient" correspondence library is formed, ensuring the accuracy and reliability of dynamic calibration. The construction process first requires clearly defining the calibration objects as capacitance, loss, ESR, and leakage current, with environmental influencing factors focusing on temperature (T) and relative humidity (RH). Samples of surface-mount aluminum electrolytic capacitors covering different specifications (including common rated capacitance, voltage, and package size) are selected to ensure sample representativeness and avoid the limitations of coefficients caused by a single specification. Then, a constant temperature and humidity test chamber was built, and temperature gradients (covering actual application scenarios, such as -40℃ to 125℃, in steps of 5℃ to 10℃) and humidity gradients (20%RH to 90%RH, in steps of 10%RH) were set. For each sample, the baseline parameters (C-based, tanδ-based, ESR-based, I_L-based) were measured first under the "standard environment (25℃, 45%RH)", and then the corresponding parameters (C-real, tanδ-real, ESR-real, I_L-real) were measured under each temperature and humidity combination. Each temperature and humidity point was tested three times and the average value was taken to reduce random errors. Then, for each sample, the deviation rate between the measured value and the reference value was calculated for the four parameters under different temperatures and humidity levels. For example, the deviation rate of temperature on capacitance ΔC_T%=(C_actual - C_base) / C_base×100%, and the deviation rate of humidity on leakage current ΔI_L_RH%=(I_L_actual - I_L_base) / I_L_base×100%. The deviation rate data of all samples were summarized, and outliers (such as data exceeding 3 times the standard deviation) were removed to ensure the validity of the data. Based on the processed data, linear / nonlinear fitting models of "environmental parameter-deviation rate" are established according to parameter type, and correction coefficients are solved: temperature correction coefficients (a, b, c): for ESR, capacitance, and loss, the fitting Δparameter% = coefficient × (T-25) is used to solve the coefficients (e.g., a is the temperature coefficient of ESR, b is the temperature coefficient of capacitance); humidity correction coefficient (d): for leakage current, the fitting ΔI_L% = d × (RH-45) is used to solve d; finally, unified correction coefficients are obtained (e.g., a = -0.008 / ℃, b = -0.001 / ℃, c = -0.002 / ℃, d = 0.02 / %RH), forming the basic data of the coefficient library. Finally, new samples that were not involved in the experiment were selected, and the parameters were tested under arbitrary non-standard temperature and humidity conditions. After correction with coefficients from the coefficient library, the deviation between the "corrected value and the baseline value under standard conditions" was compared. If the deviation exceeded the allowable range (e.g., ±2%), experimental data for the corresponding temperature and humidity range were added, the fitting model and coefficients were optimized, and the process was iterated repeatedly until the correction accuracy met the test requirements. Finally, a pre-built correction coefficient library that can be stably called was formed.

[0191] Furthermore, a single-parameter compliance assessment is performed on the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the samples, specifically including:

[0192] From the datasheet of the surface-mount aluminum electrolytic capacitor, obtain the single-parameter qualified thresholds for capacitance, loss, equivalent series resistance and stable leakage current in sequence.

[0193] Further determine the capacitance deviation threshold, loss threshold, equivalent series resistance threshold, and leakage current threshold;

[0194] Based on the corrected standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current, the capacitance deviation rate and the equivalent series resistance deviation rate are determined respectively.

[0195] Further determine whether the capacitance deviation rate is within the capacitance deviation threshold range, whether the standard loss is less than or equal to the loss threshold, whether the standard equivalent series resistance is within the equivalent series resistance threshold range, and whether the standard stable leakage current is less than or equal to the leakage current threshold, and simultaneously obtain the first judgment result of the single parameter.

[0196] Based on the first judgment result of the single parameter, the standard capacitance, standard loss, standard equivalent series resistance or standard stable leakage current with values ​​between the first single parameter threshold and the second single parameter threshold are selected, and the parameter types close to the threshold are recorded.

[0197] Based on the parameter type that is close to the threshold, the preset association threshold rule is invoked;

[0198] Based on the correlation threshold rule, verify whether the other three parameters meet the requirements;

[0199] If all individual parameters are qualified and the correlation verification is passed, the sample is deemed qualified.

[0200] If all individual parameters are qualified but the correlation verification fails, the sample is determined to be potentially faulty.

[0201] If any single parameter exceeds the threshold, the sample is deemed unqualified.

[0202] The second determination result of the single parameter is further recorded, and the sample status is marked based on the second determination result of the single parameter.

[0203] Specifically, the capacitance deviation threshold is ±10% × rated capacitance, the loss threshold is 0.15, the equivalent series resistance threshold is 1.2 times the rated equivalent series resistance, the leakage current threshold is 1.2 × discharge time threshold, the capacitance deviation rate is (standard capacitance - rated capacitance) / rated capacitance × 100%, and the equivalent series resistance deviation rate is (standard equivalent series resistance - rated equivalent series resistance) / rated equivalent series resistance × 100%. The preset association threshold rules are as follows: if the standard stable leakage current is within the range of 1.1 × rated stable leakage current to the range of rated stable leakage current, then the association threshold is standard loss ≤ 0.135 and standard equivalent series resistance ≤ 1.1 × rated equivalent series resistance; if the standard equivalent series resistance is within the range of 1.1 × rated equivalent series resistance to 1.2 × rated equivalent series resistance, then the association threshold is capacitance deviation rate ≤ ±8% and standard stable leakage current ≤ 1.1 × rated stable leakage current.

[0204] Furthermore, for parameters that meet preset threshold values, correlation verification is initiated, and a judgment result of whether the sample is qualified, potentially failed, or unqualified is output, specifically including:

[0205] Based on the second judgment result of the single parameter, the samples are divided into three categories: qualified, potentially failed, and unqualified.

[0206] Obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of qualified samples, record the sample model, test time, environmental parameters, and contact resistance, and generate a single sample test report in tabular format.

[0207] Acquire the markings of potentially failed samples, output a retest prompt signal, and clarify the parameters that need to be retested and the reasons for the failure of the associated verification;

[0208] Obtain the parameter values ​​of potentially failed samples after retesting, repeat the dynamic correction and pass / fail determination process, and update the sample status;

[0209] Record the test reports and status of all samples, and generate a batch test summary report, including the number of qualified samples, the number of unqualified samples, the number of potential failures, and the statistical distribution of key parameters.

[0210] Furthermore, a testing device for surface-mount aluminum electrolytic capacitors is proposed to implement the testing method described in any of the above embodiments, comprising:

[0211] The pad cleaning pretreatment module is used to clean the pads of surface mount aluminum electrolytic capacitors, remove oxide layers and residual solder paste, and obtain the pad cleanliness.

[0212] The contact resistance calibration module is used to obtain the sample's rated equivalent series resistance, determine the contact resistance threshold, collect contact resistance data under different contact pressures, establish an Rc-pressure correspondence model, and match the optimal contact pressure.

[0213] The sample clamping and fixing module is used to place the pre-treated sample into the patch test fixture, fix it by vacuum adsorption, adjust the contact pressure to the optimal value, and verify that the contact resistance is less than or equal to the preset threshold.

[0214] The initial parameter acquisition and discharge module is used to first acquire the initial capacitance, initial loss, and initial equivalent series resistance of the sample, then complete the sample discharge, and acquire the initial stable leakage current.

[0215] The environmental adaptive correction module is used to collect ambient temperature and humidity in real time, and call the correction coefficient library to dynamically correct the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample, so as to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample.

[0216] The pass / fail determination module is used to perform single-parameter pass / fail determination on the standard capacitance, standard loss, standard equivalent series resistance and standard stable leakage current of the sample, and then initiate associated verification for parameters that meet the preset parameter thresholds, and output the determination result of sample pass / fail, potential failure or non-pass.

[0217] The advantages of this invention are as follows: First, it specifically eliminates test interference. Taking advantage of the lack of extended leads in surface mount capacitors, it ensures the pads are free of impurities through staged pad cleaning (secondary cleaning based on residual area ratio assessment). Combined with the Rc-pressure model, it matches and verifies the optimal contact pressure, reducing the interference of pad contamination and parasitic contact resistance on parameters, thus laying the foundation for test accuracy. Second, it improves the reliability of parameter testing and judgment. First, it eliminates the influence of residual voltage on leakage current through discharge, and then dynamically corrects parameters by calling a correction coefficient library in conjunction with real-time temperature and humidity, avoiding data drift caused by non-standard environments. It innovatively adopts a "single-parameter judgment + correlation verification" mode, verifying correlation parameters for parameters close to the threshold (such as leakage current and ESR), reducing missed judgments due to multi-parameter linkage failures. Third, the device and method are highly compatible. The six modules form a closed loop of "preprocessing-calibration-clamping-acquisition-correction-judgment," with each step including verification steps (such as verifying position offset and contact resistance after clamping), ensuring test repeatability. It is suitable for factory and incoming inspection, providing an efficient and standardized solution for surface mount capacitor quality control.

[0218] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A testing method for surface-mount aluminum electrolytic capacitors, characterized in that, include: Clean the pads of surface-mount aluminum electrolytic capacitors to remove oxide layers and residual solder paste, and obtain the pad cleanliness. Obtain the rated equivalent series resistance of the sample and determine the contact resistance threshold. Collect contact resistance data under different contact pressures, establish an Rc-pressure correspondence model, and match the optimal contact pressure. The pretreated sample is placed in the patch test fixture, fixed by vacuum adsorption, and the contact pressure is adjusted to the optimal value to verify that the contact resistance is less than or equal to the preset threshold. First, obtain the initial capacitance, initial loss, and initial equivalent series resistance of the sample. Then, complete the sample discharge and collect the initial stable leakage current. The ambient temperature and humidity are collected in real time, and the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample are dynamically corrected by calling the correction coefficient library to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample. The standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample are evaluated for single-parameter compliance. Then, the parameters that meet the preset parameter thresholds are evaluated for correlation verification, and the results of the evaluation are output as qualified, potentially failed, or unqualified.

2. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 1, characterized in that, The cleaning of the pads of the surface-mount aluminum electrolytic capacitor, removing the oxide layer and residual solder paste to obtain pad cleanliness, specifically includes: Obtain the model and specifications of the surface mount aluminum electrolytic capacitor, determine the length and width of the pads, and further determine the pad area; Based on the pad area, determine the power and cleaning time of the ultrasonic cleaning tool; Start the ultrasonic cleaning tool to clean the solder pads for the first time; Obtain images of the pads after the first cleaning to further determine the area of ​​residual oxide layer on the pads; The secondary cleaning assessment value is obtained based on the ratio of the residual area to the pad area. Set a secondary cleaning assessment threshold and determine whether secondary cleaning is needed. If the secondary cleaning assessment value is greater than the secondary cleaning assessment threshold, perform secondary cleaning; if the secondary cleaning assessment value is less than or equal to the secondary cleaning assessment threshold, stop cleaning. Determine the final cleaned pad image, and obtain the residual area ratio again to determine the pad cleanliness. If the cleanliness of the solder pads is greater than or equal to the solder pad cleanliness threshold, then the sample pretreatment is confirmed to be complete. The formulas for calculating the power and cleaning time of the ultrasonic cleaning tool are as follows: In the formula, The power of the ultrasonic cleaning tool. For pad area, The cleaning time for ultrasonic cleaning tools. For cleaning power coefficient, This is the cleaning time coefficient; The formula for calculating the cleanliness of the solder pads is: In the formula, For pad cleanliness, This represents the ratio of the residual area in the final cleaned pad image.

3. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 1, characterized in that, The process of obtaining the sample's rated equivalent series resistance, determining the contact resistance threshold, collecting contact resistance data under different contact pressures, establishing an Rc-pressure correspondence model, and matching the optimal contact pressure specifically includes: The contact resistance threshold is obtained based on the rated equivalent series resistance of the chip aluminum electrolytic capacitor. The test range of contact pressure is determined by the contact resistance threshold. Based on the test range of contact pressure, pressure points are selected according to a preset step interval, and the contact resistance corresponding to each pressure point is collected by a micro-ohmmeter to obtain pressure-contact resistance data. Based on the pressure-contact resistance data, an Rc-pressure correspondence model is established; The minimum pressure value that satisfies the contact pressure being less than or equal to the contact resistance threshold is determined using the Rc-pressure correspondence model, and is taken as the optimal contact pressure. Based on the optimal contact pressure, adjust the pressure adjustment component of the patch test fixture, collect the real-time contact resistance again, obtain the first contact resistance, verify that the first contact resistance is less than or equal to the contact resistance threshold, and complete the contact resistance collaborative calibration. The formula for the Rc-pressure correspondence model is as follows: In the formula, For contact resistance, To contact pressure, The slope is the fitted slope. This is the fitting intercept.

4. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 1, characterized in that, The process of placing the pretreated sample into a patch test fixture, fixing it by vacuum adsorption, adjusting the contact pressure to the optimal value, and verifying that the contact resistance is less than or equal to a preset threshold specifically includes: Based on the optimal contact pressure, obtain the drive current of the clamp pressure regulating component; Based on the driving current, a control signal is output to the clamp pressure regulating component to adjust the initial contact pressure to the optimal contact pressure. Obtain the vacuum adsorption system parameters of the fixture, preset the adsorption negative pressure threshold, start the vacuum adsorption device, and collect the real-time adsorption pressure; Based on the judgment result that the real-time adsorption pressure is less than or equal to the adsorption negative pressure threshold, the sample is preliminarily fixed. Obtain the image of the sample position after initial fixation, and determine the offset Δx and Δy between the sample center and the center of the fixture test position. If Δx ≤ 0.1 mm and Δy ≤ 0.1 mm, the position is deemed qualified; otherwise, the position of the adsorption platform is finely adjusted. After obtaining the result of the position being deemed qualified, the real-time contact resistance is collected again to obtain the second contact resistance; Based on the verification results that the second contact resistance is less than or equal to the contact resistance threshold, it is confirmed that the sample is clamped and fixed in one go. The formula for calculating the driving current of the clamp pressure regulating component is as follows: In the formula, This is the pressure-to-current conversion factor. For driving current, The optimal contact pressure is [the pressure required to achieve this].

5. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 3, characterized in that, The acquisition of the initial capacitance, initial loss, and initial equivalent series resistance of the sample specifically includes: Determine the LCR test frequency based on the rated capacitance of the surface-mount aluminum electrolytic capacitor; Set the test voltage according to the LCR test frequency; Based on the LCR test frequency and test voltage, the initial impedance signal of the sample is acquired and decomposed to obtain the resistive and reactive components. The initial capacitance is determined by the reactance component; The initial loss is determined based on the resistive component and the initial capacitance, combined with the test frequency (LCR test frequency). Based on the LCR test frequency, switch to ESR test mode to collect the real-time equivalent series resistance of the sample; The difference between the real-time equivalent series resistance and the first contact resistance is used as the initial equivalent series resistance. The formula for calculating the initial capacitance is as follows: In the formula, For the initial capacitance, This is the reactance component; The formula for calculating the initial loss is: In the formula, For initial losses, For resistance components, This is the initial capacitance.

6. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 1, characterized in that, The further steps of completing sample discharge and acquiring the initial stable leakage current specifically include: After the high-frequency LCR module test is completed, start the discharge module and set the discharge resistor; Obtain the rated voltage of the sample and determine the discharge time threshold; The operating time of the discharge module is controlled to be greater than or equal to the discharge time threshold, and the residual voltage of the sample after discharge is collected. The discharge is confirmed to be complete when the residual voltage is less than or equal to 0.05 times the rated voltage; Based on the sample's rated voltage, set the leakage current test voltage; Based on the leakage current test voltage, the voltage is slowly applied through the leakage current module, and the stable leakage current is collected after the voltage is maintained for a preset duration. Verify that the value of the stable leakage current is within the range of 0 to the rated value of the stable leakage current, thereby determining the initial stable leakage current.

7. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 1, characterized in that, The real-time acquisition of ambient temperature and humidity, along with the use of a calibration coefficient library to dynamically correct the sample's initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current, yields the sample's standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current. Specifically, this includes: The temperature and humidity sensors integrated into the testing platform are used to collect real-time ambient temperature and real-time relative humidity. By using a pre-built correction coefficient library, the temperature correction coefficient and humidity correction coefficient corresponding to the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current are obtained respectively. Based on the real-time ambient temperature, the initial capacitance and its corresponding temperature correction coefficient, the initial capacitance is calibrated to obtain the standard capacitance. Based on real-time ambient temperature, initial loss and its corresponding temperature correction coefficient, the corrected loss is obtained as the standard loss. Based on the real-time ambient temperature, the initial equivalent series resistance and its corresponding temperature correction coefficient, the corrected standard equivalent series resistance is obtained. Based on real-time relative humidity, initial stable leakage current and its corresponding humidity correction coefficient, the corrected standard stable leakage current is obtained.

8. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 1, characterized in that, The single-parameter compliance determination of the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the samples specifically includes: From the datasheet of the surface-mount aluminum electrolytic capacitor, obtain the single-parameter qualified thresholds for capacitance, loss, equivalent series resistance and stable leakage current in sequence. Further determine the capacitance deviation threshold, loss threshold, equivalent series resistance threshold, and leakage current threshold; Based on the corrected standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current, the capacitance deviation rate and the equivalent series resistance deviation rate are determined respectively. Further determine whether the capacitance deviation rate is within the capacitance deviation threshold range, whether the standard loss is less than or equal to the loss threshold, whether the standard equivalent series resistance is within the equivalent series resistance threshold range, and whether the standard stable leakage current is less than or equal to the leakage current threshold, and simultaneously obtain the first judgment result of the single parameter. Based on the first judgment result of the single parameter, the standard capacitance, standard loss, standard equivalent series resistance or standard stable leakage current with values ​​between the first single parameter threshold and the second single parameter threshold are selected, and the parameter types close to the threshold are recorded. Based on the parameter type that is close to the threshold, the preset association threshold rule is invoked; Based on the correlation threshold rule, verify whether the other three parameters meet the requirements; If all individual parameters are qualified and the correlation verification is passed, the sample is deemed qualified. If all individual parameters are qualified but the correlation verification fails, the sample is determined to be potentially faulty. If any single parameter exceeds the threshold, the sample is deemed unqualified. The second determination result of the single parameter is further recorded, and the sample status is marked based on the second determination result of the single parameter.

9. The testing method for a surface-mount aluminum electrolytic capacitor according to claim 8, characterized in that, The step of initiating correlation verification for parameters that meet preset threshold values ​​and outputting a judgment result of whether the sample is qualified, potentially failed, or unqualified specifically includes: Based on the second judgment result of the single parameter, the samples are divided into three categories: qualified, potentially failed, and unqualified. Obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of qualified samples, record the sample model, test time, environmental parameters, and contact resistance, and generate a single sample test report in tabular format. Acquire the markings of potentially failed samples, output a retest prompt signal, and clarify the parameters that need to be retested and the reasons for the failure of the associated verification; Obtain the parameter values ​​of potentially failed samples after retesting, repeat the dynamic correction and pass / fail determination process, and update the sample status; Record the test reports and status of all samples, and generate a batch test summary report, including the number of qualified samples, the number of unqualified samples, the number of potential failures, and the statistical distribution of key parameters.

10. A testing device for surface-mount aluminum electrolytic capacitors, used to implement the testing method as described in any one of claims 1-9, characterized in that, include: A pad cleaning pretreatment module is used to clean the pads of surface mount aluminum electrolytic capacitors, remove oxide layers and residual solder paste, and obtain the pad cleanliness. The contact resistance calibration module is used to obtain the rated equivalent series resistance of the sample, determine the contact resistance threshold, collect contact resistance data under different contact pressures, establish an Rc-pressure correspondence model, and match the optimal contact pressure. The sample clamping and fixing module is used to place the pretreated sample into the patch test fixture, fix it by vacuum adsorption, adjust the contact pressure to the optimal value, and verify that the contact resistance is less than or equal to a preset threshold. The initial parameter acquisition and discharge module is used to first acquire the initial capacitance, initial loss, and initial equivalent series resistance of the sample, then complete the sample discharge, and acquire the initial stable leakage current. An environmental adaptive correction module is used to collect ambient temperature and humidity in real time, and call the correction coefficient library to dynamically correct the initial capacitance, initial loss, initial equivalent series resistance, and initial stable leakage current of the sample, so as to obtain the standard capacitance, standard loss, standard equivalent series resistance, and standard stable leakage current of the sample. The conformity determination module is used to perform single-parameter conformity determination on the standard capacitance, standard loss, standard equivalent series resistance and standard stable leakage current of the sample, and then initiate correlation verification for parameters that meet the preset parameter thresholds, and output the determination result of whether the sample is qualified, potentially failed or unqualified.

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