State evaluation method and device for aluminum electrolytic capacitor

Abstract

The invention discloses an aluminum electrolytic capacitor state evaluation method and device, and the method comprises the steps: carrying out the frequency scanning measurement of an electrolyte and oxidation film interface, and obtaining the change data of an interface polarization current phase angle along with the frequency; measuring fluid dynamic characteristics of the electrolyte according to the polarization characteristic parameters, and detecting micro-flow response characteristics; according to the flow distribution data and the evolution data, applying a voltage sequence to carry out ion migration kinetic analysis; carrying out microstructure analysis in a preset temperature change process according to the ion distribution characteristics; and according to the structure change data and the dielectric response data, analyzing the change characteristics of the molecular level, the bubble distribution and the overall performance to obtain a stability evaluation result. According to the technical scheme, through multi-dimensional analysis of the interface polarization characteristic, the fluid dynamic characteristic, the ion migration dynamics and the microstructure change of the electrolyte, effective detection of bubbles and layering phenomena in the electrolyte is realized, and accurate evaluation of the performance state of the capacitor is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitor testing, and in particular to a method and device for evaluating the state of an aluminum electrolytic capacitor. Background Art

[0002] Aluminum electrolytic capacitors are a key component widely used in electronic devices. Their working principle relies on the dielectric effect between the electrolyte and the oxide film on the surface of the aluminum foil to achieve the storage and release of electrical energy. In practical applications, aluminum electrolytic capacitors often need to work in extreme environments such as high temperature, high current and high frequency. These working conditions will cause the performance of the electrolyte to change, thereby affecting the overall performance and reliability of the capacitor. Therefore, status assessment of aluminum electrolytic capacitors is of great significance to ensure the stable operation of electronic equipment and prevent potential failures.

[0003] At present, the status assessment of aluminum electrolytic capacitors mainly relies on static test methods of parameters such as capacity, equivalent series resistance (ESR) and leakage current. However, these traditional methods have obvious limitations. During long-term operation, bubbles or stratification may appear inside the electrolyte, and these microscopic changes will significantly affect the performance of the capacitor. The formation of bubbles may cause local short circuits or local failure of the electric field, while electrolyte stratification will cause uneven electrolyte concentration and accelerate the degradation of capacitor performance. Traditional static test methods cannot effectively detect these microscopic changes because they mainly focus on the macroscopic electrical parameters of the capacitor and ignore the dynamic evolution of the internal state of the electrolyte. Especially in extreme working environments such as high temperature, high current and high frequency, these microscopic changes in the electrolyte will be more significant, but conventional testing methods often cannot detect these potential failure risks in time. This technical limitation results in the test results being unable to fully reflect the aging process and potential failure mechanism of the capacitor, which may cause serious safety hazards in high-reliability applications. Summary of the invention

[0004] The main purpose of the present invention is to solve the technical problem that the existing aluminum electrolytic capacitor testing method cannot effectively detect and evaluate the bubbles or stratification phenomenon inside the electrolyte. This problem leads to deviations in performance evaluation under extreme working environments such as high temperature, high current and high frequency, making it impossible for the test results to fully reflect the aging process and potential failure mechanism of the capacitor. Especially in high-reliability applications, it may lead to failure to timely discover the potential failure of the capacitor, affecting the overall performance and safety of the equipment.

[0005] A first aspect of the present invention provides a method for evaluating the state of an aluminum electrolytic capacitor, the method comprising: Performing frequency scanning measurement on the interface between the electrolyte and the oxide film to obtain data on the change of the interface polarization current phase angle with frequency, analyzing the interface polarization response based on the change data to obtain polarization characteristic parameters; According to the polarization characteristic parameters, the fluid dynamics characteristics of the electrolyte are measured, the micro-flow response characteristics are detected, the flow field distribution state is analyzed, and the flow distribution data and evolution data are obtained; According to the flow distribution data and the evolution data, a voltage sequence corresponding to the ion characteristics is applied to perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics; According to the ion distribution characteristics, microstructure analysis is performed under a preset temperature change process to obtain structure change data and dielectric response data; Based on the structural change data and dielectric response data, the change characteristics of the molecular level, bubble distribution and overall performance are analyzed to obtain stability evaluation results.

[0006] Preferably, the frequency scanning measurement of the interface between the electrolyte and the oxide film is performed to obtain the data of the change of the interface polarization current phase angle with the frequency, and the interface polarization response is analyzed according to the change data to obtain the polarization characteristic parameters, including: According to the ionic characteristics of the electrolyte and the pore structure characteristics of the oxide film, a high-frequency scanning interval and a low-frequency scanning interval are determined, wherein the high-frequency scanning interval is 11kHz-100kHz, and the low-frequency scanning interval is 0.1Hz-10Hz; Scanning is performed at logarithmic intervals in the high-frequency scanning interval and scanning is performed at linear intervals in the low-frequency scanning interval to obtain amplitude and phase angle data of the interface polarization current; According to the amplitude and phase angle data, the polarization current density distribution in the interface region is calculated, and the frequency dependence characteristics of the polarization current phase angle are analyzed to obtain polarization response characteristic data; Based on the polarization response characteristic data, analyzing the adsorption-desorption kinetics of electrolyte ions at the interface to obtain interface charge transfer characteristic data; The interface charge transfer characteristic data and the polarization response characteristic data are combined to analyze the time constant distribution of the interface polarization process to obtain polarization characteristic parameters.

[0007] Preferably, the polarization current density distribution in the interface region is calculated based on the amplitude and phase angle data, and the frequency dependence characteristics of the polarization current phase angle are analyzed to obtain polarization response characteristic data, including: According to the amplitude, calculating the polarization current amplitude distribution in different pore diameter regions on the surface of the oxide film to obtain the spatial distribution characteristics of the polarization current; Based on the spatial distribution characteristics and the amplitude, the attenuation law of the polarization current amplitude along the depth direction of the oxide film pores is analyzed, the polarization current density at different depths is calculated, and the depth distribution characteristics of the polarization current are obtained; Calculating the local polarization current density of the interface region according to the spatial distribution characteristics and the depth distribution characteristics, and analyzing the spatial variation law of the density distribution to obtain polarization current density data of the interface region; According to the phase angle data, the rate of change of the polarization current phase angle at different frequencies is calculated, the evolution law of the phase angle with frequency is analyzed, and the frequency characteristic data of the polarization process is obtained; The polarization current density data and the frequency characteristic data are combined to analyze the spatiotemporal characteristics of the interface polarization response to obtain polarization response characteristic data.

[0008] Preferably, the method of measuring the fluid dynamics characteristics of the electrolyte, detecting the microfluidic response characteristics, analyzing the flow field distribution state, and obtaining the flow distribution data and evolution data according to the polarization characteristic parameters includes: Based on the polarization characteristic parameters, the characteristic viscosity and density distribution of the electrolyte are calculated, and according to the natural convection characteristics of the electrolyte in the container, the optimal measurement point distribution in the axial and radial directions is determined; Applying a micro-disturbance signal matching the viscosity characteristics of the electrolyte at the optimal measurement point, wherein the frequency of the micro-disturbance signal corresponds to the characteristic frequency of the electrolyte, to obtain local flow response data of the electrolyte; Analyzing the flow field layering characteristics of the electrolyte under the action of gravity according to the local flow response data, and obtaining the flow velocity distribution and pressure gradient data of the electrolyte at different spatial positions; Based on the flow velocity distribution and pressure gradient data, combined with the viscoelastic properties of the electrolyte, the shear stress distribution of the electrolyte is calculated to obtain flow distribution data; The flow distribution data is subjected to a spatiotemporal evolution analysis to evaluate the flow stability and stratification trend of the electrolyte and obtain evolution data.

[0009] Preferably, applying a micro-disturbance signal matching the viscosity characteristics of the electrolyte at the optimal measurement point, wherein the frequency of the micro-disturbance signal corresponds to the characteristic frequency of the electrolyte, and obtaining local flow response data of the electrolyte comprises: According to the viscosity characteristics of the electrolyte at different temperatures, a temperature compensation type micro-disturbance signal matching the viscosity characteristics is designed, wherein the amplitude of the temperature compensation type micro-disturbance signal is adaptively adjusted as the temperature increases; At the optimal measurement point, based on the compression characteristics of the electrolyte under a high-voltage environment, the frequency response characteristics of the micro-disturbance signal are adjusted to correspond to the characteristic frequency of the electrolyte; In the process of applying the micro-disturbance signal, the local viscosity change of the electrolyte at the optimal measurement point is monitored in real time to obtain viscosity temperature coefficient data; According to the viscosity temperature coefficient data, the shear thinning characteristics and flow response characteristics of the electrolyte are analyzed to obtain local flow response data of the electrolyte.

[0010] Preferably, the voltage sequence corresponding to the ion characteristics is applied according to the flow distribution data and the evolution data to perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics, including: Based on the flow distribution data and the evolution data, analyzing the difference in flow states of cations and anions in the electrolyte, determining characteristic migration times of different types of ions, and generating a voltage pulse sequence including multiple amplitudes and durations; Under the action of the voltage pulse sequence, transient current response data of the electrolyte is obtained, and migration characteristic parameters of different types of ions are extracted according to the transient current response data; The migration characteristic parameters and the transient current response data are combined to analyze the spatial distribution evolution process of different types of ions to obtain ion distribution characteristics.

[0011] Preferably, the step of acquiring transient current response data of the electrolyte under the action of the voltage pulse sequence, and extracting migration characteristic parameters of different types of ions according to the transient current response data, includes: According to the charge number and ion radius characteristics of various ions in the electrolyte, the migration rate differences of ions in the electric field are analyzed to obtain the ion migration rate distribution data; In each pulse cycle of the voltage pulse sequence, multi-time scale sampling is performed on the transient current response to obtain current response components reflecting different migration time constants; Analyzing the time domain characteristics of the current response component, extracting the peak response time and current decay rate of each type of ion, and obtaining the kinetic response data of ion migration; The migration rate distribution data and the kinetic response data are combined to perform time-resolved analysis on the current contribution of cations and anions to obtain migration characteristic parameters.

[0012] Preferably, the microstructure analysis is performed under a preset temperature change process according to the ion distribution characteristics to obtain structure change data and dielectric response data, including: According to the ion distribution characteristics, the distribution state of the intermolecular force of the electrolyte is determined, and a temperature change sequence including a heating stage, a constant temperature stage and a cooling stage is designed, wherein the heating rate of the heating stage is 5°C / min, the holding time of the constant temperature stage is 30min, and the cooling rate of the cooling stage is 2°C / min; At each stage of the temperature change sequence, the dielectric loss factor and dielectric constant of the electrolyte are obtained, the temperature sensitivity of the molecular structure of the electrolyte is analyzed, and the structural change data is obtained; Based on the structural change data, the aggregation state and solvation characteristics of the electrolyte molecules are analyzed as a function of temperature, the polarization intensity and relaxation time of the electrolyte at different temperatures are calculated, and the dielectric response data are obtained.

[0013] Preferably, the analysis of the change characteristics of the molecular level, bubble distribution and overall performance according to the structural change data and the dielectric response data to obtain the stability evaluation result includes: Based on the structural change data, the aggregation degree and orientation state of the electrolyte molecular chains are analyzed, the change trend of the intermolecular interaction energy is calculated, and the molecular level stability index is obtained; Analyzing the number density, size distribution and growth rate of bubbles in the electrolyte according to the dielectric response data, and establishing bubble evolution characteristic parameters; Combining the molecular level stability index and the bubble evolution characteristic parameter, the dynamic change law of the conductivity, polarization characteristics and dielectric loss of the electrolyte is calculated to construct an overall performance evaluation index; Based on the time evolution characteristics of the overall performance evaluation index, the long-term stability of the electrolyte is evaluated to obtain a stability evaluation result.

[0014] A second aspect of the present invention provides a state assessment device for an aluminum electrolytic capacitor, the state assessment device for an aluminum electrolytic capacitor comprising: An interface polarization analysis module is used to perform frequency scanning measurement on the interface between the electrolyte and the oxide film, obtain data on the change of the interface polarization current phase angle with frequency, analyze the interface polarization response based on the change data, and obtain polarization characteristic parameters; A fluid dynamics measurement module, used to measure the fluid dynamics characteristics of the electrolyte, detect micro-flow response characteristics, analyze the flow field distribution state, and obtain flow distribution data and evolution data according to the polarization characteristic parameters; An ion migration analysis module is used to apply a voltage sequence corresponding to the ion characteristics according to the flow distribution data and the evolution data, perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics; A microstructure measurement module, used to perform microstructure analysis under a preset temperature change process according to the ion distribution characteristics, and obtain structure change data and dielectric response data; The stability evaluation module is used to analyze the change characteristics of the molecular level, bubble distribution and overall performance according to the structural change data and dielectric response data to obtain a stability evaluation result.

[0015] In this scheme, by first scanning the interface between the electrolyte and the oxide film in different frequency ranges, the change in the polarization current phase angle from high frequency to low frequency can be captured. The high-frequency part can usually reflect the dynamic response of ions when they oscillate or transition rapidly at the interface, while the low-frequency part is more related to processes such as slow diffusion and adsorption-desorption. In this way, the ion motion characteristics and local charge transfer information at the interface can be broken down in detail, not just limited to simple measurements of macroscopic parameters such as capacity or equivalent series resistance. Compared with traditional methods that can only observe overall performance, this frequency scan covers the activity patterns of ions on different time scales, so it can perceive possible signs of bubble aggregation or stratification at an earlier stage.

[0016] After obtaining the interface polarization data, the calculated polarization characteristic parameters are further combined with factors such as electrolyte viscosity and density to carry out fluid dynamics analysis and detect whether there are local flow anomalies or stratification tendencies. If there is an uneven ion concentration or temperature gradient inside the electrolyte, micro-flow stratification or eddy current phenomena may occur. In the past, it was difficult to detect this based on capacity or ESR, but here, by tracking the spatiotemporal evolution of flow data, the potential stratification problems inside can be more directly revealed. Once flow instability or intensified stratification is found at the microscopic level, it is possible to timely predict the possible failure of the capacitor under subsequent high temperature, high current, and high frequency conditions.

[0017] In addition, the scheme also sets up a voltage sequence corresponding to the ion characteristics according to the flow distribution analysis results to observe the migration dynamics of different ions. Under the action of the electric field pulse, each ion exhibits different migration speeds or response times based on its own charge and size. If the electrolyte makes it difficult for some ions to pass through a certain area due to local bubbles or changes in the solvation state, then anomalies will appear in the migration data. In this way, the distribution characteristics of different types of ions can be distinguished, helping to determine the spatial uniformity of the electrolyte, and whether there are local problems such as ion accumulation or ion vacancies.

[0018] Finally, combined with the microstructure analysis and dielectric response research under the temperature change process, it is possible to track the orientation state at the molecular level, the evolution of the number and size of bubbles, and the temperature change curves of polarization intensity and relaxation time. The comprehensive changes in these indicators will provide a more in-depth judgment on the degree of aging of the electrolyte. For example, if a violent growth of bubbles or an abnormal increase in the dielectric loss factor is detected during the heating stage, it often means that the failure risk of the capacitor is rapidly amplifying, and protective or replacement measures should be taken at this time. Through such multiple monitoring dimensions, the possible internal degradation process is better presented, so that the overall performance evaluation is no longer limited to simple external measurements.

[0019] Looking at these steps: from interface polarization to fluid movement, to ion migration and temperature evolution analysis at the molecular level, they are all closely linked to the microscopic failure paths that may occur under extreme conditions. With the help of multi-stage and multi-data source measurement and analysis, the traditional limitation of using a single macro parameter to judge whether it is aging has been broken through, and it provides the possibility of early detection of potential problems such as bubble generation, increased stratification or abnormal ion distribution. Internal changes that were difficult to locate or quantify in a timely manner in the past can now be explored through richer response data, thereby effectively addressing performance degradation and reliability risks in high temperature, high current, and high frequency environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of an embodiment of a method for evaluating the state of an aluminum electrolytic capacitor according to an embodiment of the present invention; Figure 2 Schematic diagram of an embodiment of a device for evaluating the state of an aluminum electrolytic capacitor in an embodiment of the present invention.

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, which must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] An embodiment of the present application provides a method for evaluating the status of an aluminum electrolytic capacitor. Figure 1 A flow chart of a method for evaluating the state of an aluminum electrolytic capacitor provided in an embodiment of the present application. In this embodiment, the method includes: See also Figure 1 , performing frequency scanning measurement on the interface between the electrolyte and the oxide film to obtain data on the variation of the phase angle of the interface polarization current with frequency, analyzing the interface polarization response according to the variation data to obtain polarization characteristic parameters; In one embodiment of the present invention, the frequency scanning measurement of the interface between the electrolyte and the oxide film is performed to obtain the variation data of the interface polarization current phase angle with the frequency, and the interface polarization response is analyzed according to the variation data to obtain the polarization characteristic parameters, including: According to the ionic characteristics of the electrolyte and the pore structure characteristics of the oxide film, a high-frequency scanning interval and a low-frequency scanning interval are determined, wherein the high-frequency scanning interval is 11kHz-100kHz, and the low-frequency scanning interval is 0.1Hz-10Hz; Scanning is performed at logarithmic intervals in the high-frequency scanning interval and scanning is performed at linear intervals in the low-frequency scanning interval to obtain amplitude and phase angle data of the interface polarization current; According to the amplitude and phase angle data, the polarization current density distribution in the interface region is calculated, and the frequency dependence characteristics of the polarization current phase angle are analyzed to obtain polarization response characteristic data; Based on the polarization response characteristic data, analyzing the adsorption-desorption kinetics of electrolyte ions at the interface to obtain interface charge transfer characteristic data; The interface charge transfer characteristic data and the polarization response characteristic data are combined to analyze the time constant distribution of the interface polarization process to obtain polarization characteristic parameters.

[0027] The following is a detailed description of the steps involved in the above embodiment: In the first step, when selecting two scanning frequency ranges, it is necessary to give priority to the ion species in the electrolyte and the size distribution of the pores on the oxide film surface. By analyzing the migration rate of ions in the electric field and the typical size of the oxide film pores, it is possible to locate the rapid polarization process that is obvious at higher frequencies and the slow charging and discharging behavior that occurs at lower frequencies. To achieve this process, the scanning range supported by the impedance analyzer commonly used in the laboratory can be combined to select 11kHz to 100kHz as the fast response measurement range, and 0.1Hz to 10Hz is used to capture the interval of slow ion diffusion or adsorption. Such a division can cover both the interface characteristics of the high-frequency oscillation stage and the deep polarization process in the low-frequency range. In terms of instrument selection, a digital impedance analyzer with a wide measurement bandwidth can be used, and the frequency point calibration of the scanning range can be accurately performed during the setting. An alternative is to slightly expand or reduce the high-frequency and low-frequency ranges, as long as it is ensured that the performance of ions on different time scales at the interface can be paid attention to at the same time. The implementation of this stage helps to distinguish the interface coupling effects caused by fast and slow polarization mechanisms, thereby obtaining more accurate ion dynamic information.

[0028] In the second step, after the frequency interval is delineated, different stepping methods are required for scanning. Logarithmic spacing can obtain more detailed change patterns in a wider frequency span in the high-frequency region, avoiding insufficient sampling of rapidly changing signals in polarization behavior; linear spacing can keep the difference between adjacent frequency points fixed in the low-frequency band, thereby better capturing the evolution trend of slow processes. In specific implementation, the frequency step mode of the impedance analyzer can be used for segmented configuration: enter the start frequency and end frequency in the high-frequency part, and then select the number of scan points for logarithmic distribution; in the low-frequency part, use linear distribution to set the corresponding step and scan range. If necessary, the logarithmic step of the high-frequency interval can be refined to more gears, or the low-frequency interval can be scanned more densely linearly, as long as the stability of the overall scan is ensured. This approach can obtain higher-resolution amplitude and phase angle data within the same total test time, and accurately present the characteristic curve of interface polarization in the frequency domain range of different rates.

[0029] In the third step, after completing the acquisition of the amplitude and phase angle of each scanning point, the raw data can be normalized and calculated to generate a polarization current density distribution diagram through data processing software or self-programming scripts. A feasible way is to combine the current amplitude measured on the interface with the known effective surface area to obtain the polarization current density in different regions, thereby showing its change curve in the frequency dimension. The acquisition of the phase angle provides a basis for analyzing the degree of deviation between the polarization process and the resistance-capacitance equivalent model. By observing the evolution of the phase angle with frequency, it can be determined whether the dominant mechanism of the interface is charge transfer or double-layer coupling. In specific operations, the current density and phase angle corresponding to different frequency points can be uniformly stored in the data software, and then a two-dimensional or three-dimensional visualization chart can be used to display the relationship between frequency-polarization current-phase angle. This processing method can effectively identify abnormal peaks or inflection points that appear in certain specific frequency bands, and provide detailed data for subsequent fine analysis of ion behavior.

[0030] In the fourth step, after obtaining the polarization response characteristics, the information can be used to further explore the adsorption and desorption dynamics of ions in the pores and interface areas on the surface of the oxide film. Combined with the rapid polarization performance reflected in the high-frequency band, the coupling strength between the ions and the oxide film surface in a short time scale can be inferred; and in the response of the low-frequency band, the thickness of the diffusion layer and the exchange rate that the ions need to cross can also be estimated. At this time, a small AC perturbation voltage can be applied to the test system, and combined with the collected polarization current phase angle distribution, the residence time of the ions on the pore surface and the time taken to detach from the interface can be analyzed. If it is necessary to capture these adsorption-desorption details more intuitively, it can also be detected by a higher-precision impedance analyzer in combination with optical or synchrotron radiation during the experiment, but in many mass production evaluations, relying solely on the above electrical test method is sufficient to obtain preliminary conclusions about the ion surface process. In this way, the relationship between the interface charge transfer intensity and the adsorption kinetics is quantitatively characterized, providing a basis for the subsequent time constant distribution analysis.

[0031] In the fifth step, the interface charge transfer characteristics and the previously obtained polarization response characteristics are combined to further decompose the proportion of the interface polarization process on different time scales. By comparing the special points, turning points or peak positions in the amplitude and phase angle curves of high and low frequency bands, several representative time constants can be found, and these time constants can be used to evaluate the overall polarization process of the capacitor at the interface. Data processing software or model analysis tools can classify these time constants into different groups such as fast polarization and slow polarization to form a more refined ion dynamics profile. In this way, the differences caused by factors such as pore geometry, ion mass and interface bonding energy can be more clearly characterized, thereby refining a generalized polarization characteristic parameter to measure the response stability and energy conversion efficiency of the entire system under different working conditions. In this way, in a variety of application scenarios, the evaluation of ion adsorption behavior and the judgment of electrode interface decay trends will be more targeted and accurate.

[0032] In one embodiment of the present invention, the polarization current density distribution in the interface region is calculated based on the amplitude and phase angle data, and the frequency dependence characteristics of the polarization current phase angle are analyzed to obtain polarization response characteristic data, including: According to the amplitude, calculating the polarization current amplitude distribution in different pore diameter regions on the surface of the oxide film to obtain the spatial distribution characteristics of the polarization current; Based on the spatial distribution characteristics and the amplitude, the attenuation law of the polarization current amplitude along the depth direction of the oxide film pores is analyzed, the polarization current density at different depths is calculated, and the depth distribution characteristics of the polarization current are obtained; Calculating the local polarization current density of the interface region according to the spatial distribution characteristics and the depth distribution characteristics, and analyzing the spatial variation law of the density distribution to obtain polarization current density data of the interface region; According to the phase angle data, the rate of change of the polarization current phase angle at different frequencies is calculated, the evolution law of the phase angle with frequency is analyzed, and the frequency characteristic data of the polarization process is obtained; The polarization current density data and the frequency characteristic data are combined to analyze the spatiotemporal characteristics of the interface polarization response to obtain polarization response characteristic data.

[0033] The following is a detailed description of the steps involved in the above embodiment: In the first step, after obtaining the overall measurement data, the distribution of pore sizes on the surface of the oxide film can be divided into regions, and then the corresponding polarization current amplitude map can be generated based on the current amplitude information of each region. When implementing this process, a scanning electron microscope can be used to image the surface of the sample, calibrate the pore size range at each location, and collect amplitude data in each pore area in combination with a multi-point probe or microelectrode array method. Each set of amplitude data will be recorded separately in the data processing unit. By matching the pore size with the measured amplitude, the current amplitude distribution of different pore areas can be obtained. If finer spatial accuracy is required, more areas can be partitioned under a higher magnification microscope to present the differences in surface polarization in more detail. By taking such steps, it is possible to intuitively divide which pore areas produce higher or lower polarization currents, laying a quantitative basis for the subsequent analysis of the behavior of each area in the longitudinal or depth direction.

[0034] In the second step, after the amplitude of each pore area is determined, the amplitude of each area can be segmented in the longitudinal direction in combination with the oxide film thickness data of the sample, so as to confirm the attenuation relationship of the polarization current in the pore depth direction. A feasible way is to retain several samples with different slice thicknesses during the preparation process, and repeat the above amplitude measurement on each slice surface, and finally combine the depth position corresponding to these slices with the measured amplitude value to draw a curve of amplitude variation with depth. Another approach is to use a focused ion beam to etch layer by layer at the same pore position, and perform micro-area electrochemical measurements at each etching depth to record the gradual attenuation trend of the amplitude. Regardless of which implementation method is adopted, the attenuation law along the depth direction can be obtained based on the longitudinal thickness of the pore and the amplitude difference at adjacent depth positions, and the polarization current density of each depth layer can be calculated in the data processing software. The depth distribution characteristics obtained in this way can indicate the degree of restriction on current transmission inside the pore and provide a quantitative basis for evaluating the transmission resistance of ions in the deep part of the pore.

[0035] In the third step, after mastering the spatial distribution and depth distribution, the two can be fused to obtain the local polarization current density of the interface area, and sort out the comprehensive changes in the plane and depth directions of each position. In order to achieve this process, the spatial coordinates (such as aperture area) and depth coordinates (such as slice order) can be integrated into a set of three-dimensional coordinate mappings in the data analysis program, and the corresponding current density value is placed at each coordinate point. A continuous density distribution map is generated through interpolation or fitting algorithms. The different depth layers of each aperture section can also be recorded one by one in a table or database for subsequent comparison. After such processing, the difference in the degree of polarization of the oxide film at different apertures and different depths can be accurately determined, so as to evaluate which local areas are more prone to overheating or ion accumulation in specific usage scenarios, so as to facilitate the adoption of more targeted design improvements or quality screening methods.

[0036] In the fourth step, the phase angle data collected during the frequency scan is used to calculate the rate of change of the polarization current phase angle between adjacent frequency points, thereby identifying which frequency sections have obvious phase angle turning points or mutations. During implementation, the curve of the phase angle changing with frequency can be extracted in the impedance analyzer or dedicated measurement software, and the rate of change of the phase angle can be calculated by interpolation or differential algorithm, or the key frequency points and turning point positions can be extracted using curve fitting technology. If higher accuracy is required, the phase angle can be measured separately in each key frequency band in combination with a phase-locked amplifier to obtain more detailed rate distribution data. The curve obtained in this way can intuitively show whether the dominant mechanism or coupling effect of the polarization process has mutated in the high-frequency range or low-frequency range, which is explanatory for determining the dissipation characteristics of ions on the membrane surface or deep in the pores.

[0037] In the fifth step, the local polarization current density distribution obtained from the above steps is linked to the phase angle change of the frequency characteristics, which can further understand the response morphology of the interface polarization in time and space. When executed, the three-dimensional density distribution and the phase angle evolution curve can be superimposed on the data visualization interface, and the interface polarization can be analyzed under different time constants based on the combination of frequency interval and spatial coordinates. If quantitative comparison is required, different regions and frequency bands can be grouped based on the clustering algorithm of three-dimensional data points, and the average polarization current density and phase angle rate values ​​in each group can be calculated to determine whether there is a high activity area that is obviously related to the pore size or depth. The resulting description of spatiotemporal characteristics provides a more targeted reference indicator for optimizing the oxide film structure or improving the electrolyte formulation, and can effectively identify interface failure hazards in practical applications.

[0038] Please continue reading Figure 1 , according to the polarization characteristic parameters, measuring the fluid dynamics characteristics of the electrolyte, detecting the micro-flow response characteristics, analyzing the flow field distribution state, and obtaining the flow distribution data and evolution data; In one embodiment of the present invention, the method of measuring the fluid dynamics characteristics of the electrolyte, detecting the microfluidic response characteristics, analyzing the flow field distribution state, and obtaining the flow distribution data and evolution data according to the polarization characteristic parameters includes: Based on the polarization characteristic parameters, the characteristic viscosity and density distribution of the electrolyte are calculated, and according to the natural convection characteristics of the electrolyte in the container, the optimal measurement point distribution in the axial and radial directions is determined; Applying a micro-disturbance signal matching the viscosity characteristics of the electrolyte at the optimal measurement point, wherein the frequency of the micro-disturbance signal corresponds to the characteristic frequency of the electrolyte, to obtain local flow response data of the electrolyte; Analyzing the flow field layering characteristics of the electrolyte under the action of gravity according to the local flow response data, and obtaining the flow velocity distribution and pressure gradient data of the electrolyte at different spatial positions; Based on the flow velocity distribution and pressure gradient data, combined with the viscoelastic properties of the electrolyte, the shear stress distribution of the electrolyte is calculated to obtain flow distribution data; The flow distribution data is subjected to a spatiotemporal evolution analysis to evaluate the flow stability and stratification trend of the electrolyte and obtain evolution data.

[0039] The following is a detailed description of the steps involved in the above embodiment: In the first step, when determining the characteristic viscosity and density distribution of the electrolyte, the correlation between ion movement and solvation degree can be derived based on the polarization characteristic parameters, and then the correlation can be numerically fitted to obtain the change of the internal viscosity of the liquid at different temperatures or local concentrations. In order to adapt these values ​​to the actual use scenario, the viscosity and density of the medium under several known temperature and ion concentration conditions can be tested on a common rheometer or densitometer, and then these measured values ​​can be mapped to the entire container using a multivariate interpolation method. After completing the calculation of the viscosity and density distribution, it is necessary to consider the fluid movement mode caused by natural convection to identify representative pressure, velocity or temperature gradients at different axial and radial positions of the container. To this end, a container and its internal fluid model can be established in the simulation software first. After inputting parameters such as viscosity, density and heat conduction, a steady-state or transient simulation can be run to observe the location of the eddy and convection mainstream areas, and then the axial and radial positions with significant gradients or turbulence phenomena in these areas are selected as the optimal measurement points for subsequent micro-disturbance signal application and data acquisition. This can make the subsequent measurement results more representative and targeted, and avoid invalid measurements in areas where the flow field does not change significantly.

[0040] In the second step, after the appropriate measurement points in the axial and radial directions have been identified in the previous step, a small amplitude perturbation matching the viscosity characteristics of the electrolyte can be applied at each measurement point to capture the local flow response. The micro-perturbation signal is usually provided by an arbitrary waveform generator or a programmable control source, and by setting the waveform frequency to be consistent with the characteristic frequency of the liquid, the fluid can produce micro-vibrations that are sufficient to be sensed but will not destroy the balance of the flow field. If the excitation amplitude and viscosity are simultaneously guaranteed to correspond to the characteristic frequency, the response of the medium to the frequency input can be effectively extracted. As an alternative, it is also possible to inject extremely small amounts of bubbles or tracer particles in a pulsed manner so that the local vortex structure can be tracked optically. After these steps, the acquisition system will record the local pressure fluctuations, flow velocity changes or vibration amplitudes at the corresponding measurement points in real time and form a local flow response data set. Using this type of method, a clearer characterization of the viscosity-dominated behavior within the characteristic frequency range can be obtained.

[0041] In the third step, after completing the disturbance of the measuring point and acquiring the data, the stratification trend and flow field stratification structure of the entire liquid under the influence of gravity can be analyzed based on the local flow response data. To achieve this process, several sensors (such as micro pressure sensors or ultrasonic flow probes) are usually arranged at the measuring point, and then the signals measured at different heights or radial positions are curve fitted to determine whether there is an obvious interface or stratification caused by density differences in the local area. If the flow response data shows a pressure or velocity gradient that is significantly different from the surrounding area in a specific area, it can be determined that the area has stratification characteristics. For containers with a large liquid height, multiple additional measuring points can be added along the axial direction to ensure that the stratification phenomenon is more fully observed. Finally, a set of data tables containing spatial distribution positions and corresponding flow velocities and pressure values ​​can be obtained, providing the necessary original information for subsequent calculations.

[0042] In the fourth step, after mastering the local flow velocity and pressure distribution, the viscoelastic properties of the electrolyte need to be taken into account in order to more accurately calculate the shear stress distribution of the liquid. A common practice is to first measure the stress-strain curve of the electrolyte in the rheometer and establish a viscoelastic constitutive model, and then input the flow velocity distribution and pressure gradient data in the numerical analysis tool, and jointly solve it with the constitutive model. In this way, the shear stress value on each spatial grid unit or discrete sampling point can be obtained. In some cases, if it is necessary to examine the nonlinear viscoelastic effect, the high-order fluid model can also be embedded in the corresponding simulation platform. For engineering applications with larger data volumes, the interpolation algorithm can also be used to expand the shear stress value at a known position to the entire flow field based on multiple measurement points. With this processing method, the flow of the electrolyte under complex boundaries and gravity fields can be presented more realistically, and flow distribution data can be formed.

[0043] In the fifth step, the last step is to interactively analyze the flow distribution data obtained previously in time and space to evaluate the flow stability of the electrolyte and the potential risk of stratification. To achieve this, the flow velocity, pressure and shear stress distribution collected for each time period can be stored separately, and their changes at different times can be monitored through a visual interface or post-processing algorithm. If it is observed that the shear stress boundary moves over time or the pressure distribution produces a dividing line in the axial direction, it means that the fluid begins to show unstable phenomena such as stratification or vortex shedding in this area. It is also possible to quickly determine whether these unstable areas will continue to expand or ease based on historical data comparison. After summarizing these observations and analysis results, the dynamic laws of electrolyte flow under different working conditions can be presented in the form of evolutionary data, and provide a reference for evaluating its long-term stability and subsequent improvement measures.

[0044] In one embodiment of the present invention, applying a micro-disturbance signal matching the viscosity characteristics of the electrolyte at the optimal measurement point, wherein the frequency of the micro-disturbance signal corresponds to the characteristic frequency of the electrolyte, and obtaining local flow response data of the electrolyte includes: According to the viscosity characteristics of the electrolyte at different temperatures, a temperature compensation type micro-disturbance signal matching the viscosity characteristics is designed, wherein the amplitude of the temperature compensation type micro-disturbance signal is adaptively adjusted as the temperature increases; At the optimal measurement point, based on the compression characteristics of the electrolyte under a high-voltage environment, the frequency response characteristics of the micro-disturbance signal are adjusted to correspond to the characteristic frequency of the electrolyte; In the process of applying the micro-disturbance signal, the local viscosity change of the electrolyte at the optimal measurement point is monitored in real time to obtain viscosity temperature coefficient data; According to the viscosity temperature coefficient data, the shear thinning characteristics and flow response characteristics of the electrolyte are analyzed to obtain local flow response data of the electrolyte.

[0045] The following is a detailed description of the steps involved in the above embodiment: In the first step, before designing the micro-disturbance signal for different temperature ranges, it is necessary to first measure the viscosity curve of the electrolyte under multiple sets of temperature conditions, and use a rheometer or an online viscosity sensor in a laboratory environment to record the viscosity value corresponding to each temperature. These values ​​can then be input into an interpolation algorithm or a fitting function to obtain a temperature-viscosity correlation. Based on this correlation, combined with the temperature change trend of the actual use environment, an input signal including an amplitude adaptation mechanism is set: when the temperature gradually increases, the signal generator can automatically increase the amplitude of the micro-disturbance waveform to ensure that the appropriate excitation intensity is maintained after the viscosity decreases. If special attention needs to be paid to certain temperature sections, a separate amplification coefficient function can be set to make the amplitude adjustment more suitable for local temperature conditions. In this way, insufficient test sensitivity due to increased electrolyte fluidity at high temperatures can be avoided.

[0046] In the second step, when the measurement point position has been determined, if the experimental environment also involves higher pressure, it is necessary to fully consider the impact of the compression effect of the electrolyte on the characteristic frequency of the flow. To this end, the frequency response characteristics of the disturbance waveform can be adjusted to meet the intrinsic response range of the electrolyte under the current pressure environment with the help of a programmable signal source. During execution, one method is to first estimate the characteristic frequency of the electrolyte at the pressure based on numerical simulation or existing high-pressure rheological data, and then adjust the center frequency or main harmonic component of the output waveform accordingly on the test control panel. If further pressure rise and fall of the liquid is observed in the high-pressure container later, the pressure value collected by the sensor can also be used for rapid feedback, so that the signal source can be kept in the range of resonance or high-sensitivity coupling with the liquid at any time. If it is inconvenient to use programming, the measurement results of multiple fixed frequency points can be manually compared, and then the frequency that can maximize the detection accuracy can be selected. This can better collect the true response of the electrolyte to micro-perturbations under high-pressure environments.

[0047] In the third step, after the high pressure and temperature compensation are set accordingly, the micro-disturbance signal can be applied to the pre-selected key measurement point, and the real-time changes can be captured by the micro-flow and viscosity sensing unit arranged at the location. A common practice is to use a small cantilever viscosity probe to continuously monitor the medium stress changes and flow velocity fluctuations at that location. For the same measurement point at different temperatures, the mechanical or electrical signal output by the probe can be converted into a viscosity value, and the difference or ratio of viscosity to temperature can be calculated in the control system to obtain the viscosity temperature coefficient. If more detailed data is required, multiple measurements can be made at the same measurement point, and then the noise can be reduced by interpolation or filtering algorithms to finally obtain a higher-precision viscosity-temperature correspondence curve. In this way, the sensitivity of the viscosity of the local area to temperature fluctuations can be identified, providing a more targeted reference for subsequent judgment of flow behavior.

[0048] In the fourth step, after mastering the viscosity temperature coefficient, the flow response of the area can be further evaluated based on the existing rheological knowledge. For the shear thinning phenomenon, the flow morphology of the liquid in the corresponding temperature section can be judged by referring to the decrease ratio of viscosity at different temperatures with increasing shear rate. If the monitoring data shows that the viscosity decreases rapidly when the temperature rises, and there is a significant thinning trend within a certain flow rate range, it can be inferred that it is easier to form rapid convection or local turbulence. If a more visual analysis is required, the measured viscosity temperature coefficient and flow velocity distribution data can be input into the numerical simulation platform, and the transient flow field simulation can be run to view the location of the shear band and flow stratification phenomenon. With the help of this type of analysis results, the real flow response of the electrolyte in the local area can be obtained, which is helpful to make corresponding design or operation adjustments for high temperature and high pressure conditions in subsequent applications.

[0049] Please continue reading Figure 1 , according to the flow distribution data and evolution data, applying a voltage sequence corresponding to the ion characteristics, performing ion migration kinetics analysis, obtaining migration response data of different types of ions, and obtaining ion distribution characteristics; In one embodiment of the present invention, applying a voltage sequence corresponding to ion characteristics according to the flow distribution data and evolution data, performing ion migration kinetics analysis, obtaining migration response data of different types of ions, and obtaining ion distribution characteristics include: Based on the flow distribution data and the evolution data, analyzing the difference in flow states of cations and anions in the electrolyte, determining characteristic migration times of different types of ions, and generating a voltage pulse sequence including multiple amplitudes and durations; Under the action of the voltage pulse sequence, transient current response data of the electrolyte is obtained, and migration characteristic parameters of different types of ions are extracted according to the transient current response data; The migration characteristic parameters and the transient current response data are combined to analyze the spatial distribution evolution process of different types of ions to obtain ion distribution characteristics.

[0050] The following is a detailed description of the steps involved in the above embodiment: In the first step, after obtaining the flow distribution data and evolution data generated in the previous stage, if the movement differences of ions of different charge types in the flow field are to be analyzed, it is necessary to first identify their differences in local velocity, concentration gradient, and medium viscosity. To achieve this process, the previously obtained three-dimensional flow velocity, pressure or shear stress distribution can be used to combine this information with factors such as the charge characteristics of the ions, ionic radius, and electrolyte composition to determine the typical movement speed of cations and anions. Subsequently, the characteristic migration time of cations or anions can be defined with reference to the time required for the cations or anions to have an obvious transport response from the application of the electric field. After these characteristic times are determined, a series of pulse signals with different amplitudes and different durations are configured using a common arbitrary waveform generator to stimulate faster ions and slower ions respectively; in cases where more ion types need to be distinguished, the amplitude and duration of the pulse signal can also be set to multiple adjustable levels. The data processing and waveform generation in this step enable subsequent measurements to more focusedly detect the transient transport trajectory of each type of ion.

[0051] In the second step, after the pulse sequence is set up, these pulse signals can be applied to the electrolyte and the transient current changes can be obtained in real time through a high-speed acquisition system. The common method is to connect the measurement circuit to a digital oscilloscope or a high-resolution electrochemical workstation to capture the details of the signal rise and decay segments at a sufficiently fast sampling rate. By comparing the current curves at different pulse amplitudes or durations, the response segments contributed by cation movement and anion movement can be separated. If the application requires finer resolution, a short interval can be arranged between the pulse signals, and the residual current can be measured during this interval to further distinguish the decay characteristics of different ions. These transient data can then be numerically fitted or peak detected to refine the migration characteristic parameters such as the rise time, peak position, and attenuation coefficient corresponding to each ion. In this way, the dynamic details of ions under electric field pulse excitation can be accurately characterized in a relatively intuitive data form.

[0052] In the third step, after extracting key indicators such as the rise time or attenuation coefficient of different ions, it is necessary to combine the transient current curves obtained at each moment to conduct a comprehensive analysis of the distribution changes of the ions. An effective approach is to divide the electrolyte space into several areas, and then judge the time points when cations or anions appear or leave these areas based on the current changes recorded during each pulse. If higher accuracy is required, multiple sets of electrodes or sensor points can be arranged inside the container, and a roadmap for ion concentration diffusion or accumulation can be obtained by comparing the delay and amplitude of the current peaks at various locations. For occasions that require visualization, a moment-by-moment ion distribution diagram can be generated in the software to show how cations and anions shift positions over time under the action of the flow field and electric field excitation. The distribution information obtained in this way can not only be used to determine the uniformity of the electrolyte under extreme conditions, but also provide basic data for subsequent assessments of reaction efficiency or failure risks.

[0053] In one embodiment of the present invention, the step of acquiring transient current response data of the electrolyte under the action of the voltage pulse sequence, and extracting migration characteristic parameters of different types of ions according to the transient current response data, includes: According to the charge number and ion radius characteristics of various ions in the electrolyte, the migration rate differences of ions in the electric field are analyzed to obtain the ion migration rate distribution data; In each pulse cycle of the voltage pulse sequence, multi-time scale sampling is performed on the transient current response to obtain current response components reflecting different migration time constants; Analyzing the time domain characteristics of the current response component, extracting the peak response time and current decay rate of each type of ion, and obtaining the kinetic response data of ion migration; The migration rate distribution data and the kinetic response data are combined to perform time-resolved analysis on the current contribution of cations and anions to obtain migration characteristic parameters.

[0054] The following is a detailed description of the steps involved in the above embodiment: In the first step, when obtaining the difference in migration rate based on the charge number and ion radius characteristics, the basic physical and chemical parameters of the corresponding ions can be queried first, including the charge, ion radius, and diffusion coefficient in a specified solvent environment. These values ​​can be determined through existing literature databases or chemical analysis manuals, and samples can be preliminarily calibrated in the laboratory using a common ion mobility tester. The above parameters are then input into the ion migration model in the data processing software, and known boundary conditions such as the internal temperature and viscosity of the electrolyte are considered to obtain the theoretical migration rate distribution curves of various types of ions. If there are multiple types of ions, the combination of charge and ion radius can be calculated separately to show the difference in ion migration speed in the same coordinate system. Through this process, it is possible to clearly grasp the strength of the net driving force on different ions in the electric field, clarify the speed of movement of each ion, and lay a numerical basis for subsequent multi-time scale current acquisition and ion differentiation.

[0055] In the second step, when multi-time scale sampling is used within each pulse cycle of the voltage pulse sequence, a digital oscilloscope or electrochemical workstation with high sampling rate and multi-channel function is generally required to divide the captured transient current signal into several intervals according to the time period. The duration of each interval can be set according to the ion migration rate calculated previously, and sufficient monitoring intervals can be reserved for the peak response or decay process that may occur for each type of ion. For example, a pulse cycle can be divided into multiple time windows of fixed length, or longer sampling intervals can be arranged for ions with known slower migration speeds. In these ways, the current signal components corresponding to different migration time constants can be distinguished in a single pulse excitation, creating conditions for further separation and analysis.

[0056] In the third step, after completing the sampling of the current response components, the time domain analysis algorithm can be used to perform peak tracking and attenuation coefficient extraction on these data. The specific operation is to first arrange each segment of sampling data in chronological order, and then identify the time when the current maximum value occurs through curve fitting or wavelet transform, and then obtain the peak response time. At the same time, the current decay rate coefficient corresponding to each ion can be calculated through the exponential decay model or other common time domain feature extraction methods. An alternative operation is to perform a Fourier transform on the transient signal, distinguish the components that appear on different time scales in the frequency domain, and then project them back to the time domain to lock the decay process of each ion. After such processing, the kinetic response of multiple ions can be obtained, clearly showing the timing differences in the release or transmission of various types of ions under external pulses.

[0057] In the fourth step, the above migration rate distribution is combined with the kinetic indicators such as peak time and decay rate extracted in the pulse test to complete the current contribution separation and time-resolved analysis of cations and anions. A feasible approach is to set two or more segments, use the previous ion migration rate curve as prior information, attribute the current signal components within the pulse period to ions of different charge types, and superimpose and compare their peak positions and decay slopes in the software. If a certain segment is monitored to contribute more to the total current and is consistent with the characteristic rate of cations, it can be determined that the segment is dominated by cations; if the other segment is similar to the velocity distribution of anions, it is attributed to the contribution of anions. Through these matches and distinctions, clearer migration characteristic parameters are obtained, which are used to evaluate the synchronization and distribution of various ion movements in the electrolyte under different working conditions.

[0058] Please continue reading Figure 1 , performing microstructure analysis under a preset temperature change process according to the ion distribution characteristics to obtain structure change data and dielectric response data; In one embodiment of the present invention, performing microstructure analysis under a preset temperature change process according to the ion distribution characteristics to obtain structure change data and dielectric response data includes: According to the ion distribution characteristics, the distribution state of the intermolecular force of the electrolyte is determined, and a temperature change sequence including a heating stage, a constant temperature stage and a cooling stage is designed, wherein the heating rate of the heating stage is 5°C / min, the holding time of the constant temperature stage is 30min, and the cooling rate of the cooling stage is 2°C / min; At each stage of the temperature change sequence, the dielectric loss factor and dielectric constant of the electrolyte are obtained, the temperature sensitivity of the molecular structure of the electrolyte is analyzed, and the structural change data is obtained; Based on the structural change data, the aggregation state and solvation characteristics of the electrolyte molecules are analyzed as a function of temperature, the polarization intensity and relaxation time of the electrolyte at different temperatures are calculated, and the dielectric response data are obtained.

[0059] The following is a detailed description of the steps involved in the above embodiment: In the first step, after confirming the distribution characteristics of various ions, the mutual attraction or repulsion characteristics of different ions in the liquid environment can be obtained by measuring or querying the data, and the overall distribution of intermolecular forces can be determined based on these characteristics. Subsequently, the operation sequence of heating, constant temperature and cooling needs to be pre-set in the programmable temperature control device or constant temperature circulation equipment, so that the liquid is gradually heated to the target temperature at a rate of 5℃ / min, and then kept stable for 30 minutes, and finally cooled back to a lower temperature at a rate of 2℃ / min. Controlling the heating rate at 5℃ / min can avoid thermal shock and transfer internal heat more evenly; keeping it for 30 minutes helps the intermolecular forces to fully show their true mutual influence in a high temperature environment; setting the cooling rate to 2℃ / min can reserve a relatively stable buffer process for molecular rearrangement while lowering the temperature. The consideration of this stage is to enhance the resolution of the evolution process of intermolecular forces through the three-stage time-sharing control method, and realize the fine observation of the changes in the internal molecular structure of the liquid in different heating and cooling intervals.

[0060] In the second step, when collecting the dielectric loss factor and dielectric constant at each temperature stage, a dielectric testing instrument used in conjunction with a temperature control device can be used. The specific operation is to keep the internal stirring stable and record the dielectric loss factor and dielectric constant at that moment after each temperature reaches the preset value to reflect the molecular dipole orientation and charge transfer characteristics. If the measurement efficiency needs to be improved, multi-point synchronous collection can also be performed during the heating and cooling process to obtain a more continuous numerical curve. The purpose of this step is to identify the response intensity of the electrolyte to thermal conditions through changes in electrical parameters, and to distinguish within which temperature range the molecular structure is more likely to be stable or significantly adjusted. The same set of test methods can be used to quantify microstructural changes in different temperature periods, which is suitable for parallel comparison of electrolytes with different formulations or under different working conditions.

[0061] In the third step, after completing the data collection of the dielectric loss factor and dielectric constant, these results can be compared with the characteristic values ​​that appear at different temperature stages to determine whether the molecules undergo significant aggregation or solvation changes in the high or low temperature sections. To ensure data accuracy, the corresponding temperature intervals can be marked section by section in the data recording software, and the fluctuation range of the dielectric loss or dielectric constant in each interval can be calculated. Subsequently, by comparing the degree of polarization change of the molecules under heating and cooling conditions, the values ​​of the polarization intensity and relaxation time can be obtained respectively. If a shorter relaxation time appears in a certain temperature interval, it means that the molecular structure is more susceptible to the influence of the external electric field; if the polarization intensity increases, it means that the molecular orientation is more flexible. The purpose here is to directly deduce the microscopic arrangement and molecular motion characteristics of the electrolyte based on the measurement data at different stages, so as to more accurately grasp the evolution of the internal molecular structure in multiple temperature sections.

[0062] Please continue reading Figure 1 According to the structural change data and dielectric response data, the change characteristics of the molecular level, bubble distribution and overall performance are analyzed to obtain the stability evaluation results.

[0063] In one embodiment of the present invention, the analysis of the change characteristics of the molecular level, bubble distribution and overall performance based on the structural change data and the dielectric response data to obtain the stability evaluation result includes: Based on the structural change data, the aggregation degree and orientation state of the electrolyte molecular chains are analyzed, the change trend of the intermolecular interaction energy is calculated, and the molecular level stability index is obtained; Analyzing the number density, size distribution and growth rate of bubbles in the electrolyte according to the dielectric response data, and establishing bubble evolution characteristic parameters; Combining the molecular level stability index and the bubble evolution characteristic parameter, the dynamic change law of the conductivity, polarization characteristics and dielectric loss of the electrolyte is calculated to construct an overall performance evaluation index; Based on the time evolution characteristics of the overall performance evaluation index, the long-term stability of the electrolyte is evaluated to obtain a stability evaluation result.

[0064] The following is a detailed description of the steps involved in the above embodiment: In the first step, after obtaining the structural change data of the electrolyte, the degree of aggregation and orientation state can be evaluated by comparing the length, curling and dispersion of the molecular chains at different sampling times. If you need to obtain the arrangement direction of the molecular chains more intuitively, you can use a detector with optical transmission or infrared absorption function to perform segmented temperature tests on the liquid and record the differences in peak intensity and peak position as the conditions change. Using these differences, the attraction and repulsion between molecular chains can be approximately quantified, thereby inferring the trend of the strength of intermolecular interactions changing with conditions. By establishing a set of reference values ​​for intermolecular interaction energy, a molecular-level stability index that describes the degree of order maintained by the system at the microscopic scale can be obtained. The effect presented by this operation is that it can confirm whether the molecular chains can stably maintain their uniform or ordered state under different environmental conditions, thereby providing targeted microscopic parameters for the subsequent evaluation of the overall performance of the electrolyte.

[0065] In the second step, based on the dielectric response information measured in the early stage, the number and size of bubbles inside the liquid can be observed within a certain time interval to identify the law of their change with external factors. To achieve this process, a high-speed camera or laser ranging device can be equipped on the transparent reaction container to count the bubbles that appear, and then obtain the number density of bubbles in a unit volume and the maximum or average diameter. If it is necessary to record the growth rate, images or signals at the same position can be collected multiple times under constant or variable temperature conditions, and the gradual changes in bubble size over time can be compared. In this way, the characteristic values ​​required for bubble evolution can be extracted more accurately without destroying the internal environment of the liquid. This operation is meaningful for the subsequent judgment of whether the liquid is prone to significant vaporization or stratification under thermal or electric field conditions, and can provide a quantifiable indicator for evaluating the stability of the liquid.

[0066] In the third step, the stability index obtained based on the molecular structure level is combined with the bubble evolution characteristics to further deduce the dynamic change trends related to conductivity, polarization behavior and dielectric loss. For specific implementation, the molecular stability, bubble distribution and electrical measurement results can be matched on the same data processing platform to find the correspondence between the indicators at different time nodes or under different operating conditions. If a significant decrease in molecular-level indicators and an increase in bubbles are observed under a certain environmental change, it is often accompanied by a large dielectric loss; if the molecular chains are still tightly arranged and the bubble evolution is slow, the conductivity and polarization characteristics are usually more stable. Through this multi-dimensional fusion, a more systematic overall performance evaluation index can be obtained, showing the main electrical and physical characteristics of the liquid during operation, and confirming whether it has signs of attenuation or failure under certain conditions.

[0067] In the fourth step, based on the overall performance evaluation indicators, the long-term stability of the electrolyte can be determined by tracking its evolution over time. This is achieved by placing the evaluation indicators of multiple test batches on a unified timeline, observing the rising or falling trends of several important parameters (such as conductivity, polarization intensity, and loss value), and determining whether there are critical points or obvious nonlinear jumps. If the evaluation indicator remains in a stable range for a long time, it means that the electrolyte has a strong maintenance ability; if rapid fluctuations or continuous deterioration occur, further examination of the causes of changes within the system is required. Through this time evolution analysis, the results of evaluating the overall reliability of the electrolyte under actual use or accelerated aging conditions can be obtained, providing data support for deciding whether the formula needs to be changed or the operating conditions need to be optimized.

[0068] The above describes the state evaluation method of the aluminum electrolytic capacitor in the embodiment of the present invention. The following describes the state evaluation device of the aluminum electrolytic capacitor in the embodiment of the present invention. Figure 2, an embodiment of a state assessment device for an aluminum electrolytic capacitor in an embodiment of the present invention includes: The interface polarization analysis module 101 is used to perform frequency scanning measurement on the interface between the electrolyte and the oxide film, obtain the data of the change of the interface polarization current phase angle with the frequency, analyze the interface polarization response according to the change data, and obtain the polarization characteristic parameters; A fluid dynamics measurement module 102, for measuring the fluid dynamics characteristics of the electrolyte, detecting micro-flow response characteristics, analyzing the flow field distribution state, and obtaining flow distribution data and evolution data according to the polarization characteristic parameters; The ion migration analysis module 103 is used to apply a voltage sequence corresponding to the ion characteristics according to the flow distribution data and the evolution data, perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics; A microstructure measurement module 104 is used to perform microstructure analysis under a preset temperature change process according to the ion distribution characteristics to obtain structure change data and dielectric response data; The stability evaluation module 105 is used to analyze the change characteristics of the molecular level, bubble distribution and overall performance according to the structural change data and the dielectric response data to obtain a stability evaluation result.

[0069] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for evaluating the state of an aluminum electrolytic capacitor, characterized in that: include: Performing frequency scanning measurement on the interface between the electrolyte and the oxide film to obtain data on the change of the interface polarization current phase angle with frequency, analyzing the interface polarization response based on the change data to obtain polarization characteristic parameters; According to the polarization characteristic parameters, the fluid dynamics characteristics of the electrolyte are measured, the micro-flow response characteristics are detected, the flow field distribution state is analyzed, and the flow distribution data and evolution data are obtained; According to the flow distribution data and the evolution data, a voltage sequence corresponding to the ion characteristics is applied to perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics; According to the ion distribution characteristics, microstructure analysis is performed under a preset temperature change process to obtain structure change data and dielectric response data; Based on the structural change data and dielectric response data, the change characteristics of the molecular level, bubble distribution and overall performance are analyzed to obtain stability evaluation results.

2. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 1, characterized in that: The frequency scanning measurement is performed on the interface between the electrolyte and the oxide film to obtain the data of the change of the interface polarization current phase angle with the frequency, and the interface polarization response is analyzed according to the change data to obtain the polarization characteristic parameters, including: According to the ionic characteristics of the electrolyte and the pore structure characteristics of the oxide film, a high-frequency scanning interval and a low-frequency scanning interval are determined, wherein the high-frequency scanning interval is 11kHz-100kHz, and the low-frequency scanning interval is 0.1Hz-10Hz; Scanning is performed at logarithmic intervals in the high-frequency scanning interval and scanning is performed at linear intervals in the low-frequency scanning interval to obtain amplitude and phase angle data of the interface polarization current; According to the amplitude and phase angle data, the polarization current density distribution in the interface region is calculated, and the frequency dependence characteristics of the polarization current phase angle are analyzed to obtain polarization response characteristic data; Based on the polarization response characteristic data, analyzing the adsorption-desorption kinetics of electrolyte ions at the interface to obtain interface charge transfer characteristic data; The interface charge transfer characteristic data and the polarization response characteristic data are combined to analyze the time constant distribution of the interface polarization process to obtain polarization characteristic parameters.

3. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 2, characterized in that: The polarization current density distribution in the interface region is calculated based on the amplitude and phase angle data, and the frequency dependence characteristics of the polarization current phase angle are analyzed to obtain polarization response characteristic data, including: According to the amplitude, calculating the polarization current amplitude distribution in different pore diameter regions on the surface of the oxide film to obtain the spatial distribution characteristics of the polarization current; Based on the spatial distribution characteristics and the amplitude, the attenuation law of the polarization current amplitude along the depth direction of the oxide film pores is analyzed, the polarization current density at different depths is calculated, and the depth distribution characteristics of the polarization current are obtained; Calculating the local polarization current density of the interface region according to the spatial distribution characteristics and the depth distribution characteristics, and analyzing the spatial variation law of the density distribution to obtain polarization current density data of the interface region; According to the phase angle data, the rate of change of the polarization current phase angle at different frequencies is calculated, the evolution law of the phase angle with frequency is analyzed, and the frequency characteristic data of the polarization process is obtained; The polarization current density data and the frequency characteristic data are combined to analyze the spatiotemporal characteristics of the interface polarization response to obtain polarization response characteristic data.

4. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 1, characterized in that: The method of measuring the fluid dynamics characteristics of the electrolyte, detecting the microfluidic response characteristics, analyzing the flow field distribution state, and obtaining the flow distribution data and evolution data according to the polarization characteristic parameters includes: Based on the polarization characteristic parameters, the characteristic viscosity and density distribution of the electrolyte are calculated, and according to the natural convection characteristics of the electrolyte in the container, the optimal measurement point distribution in the axial and radial directions is determined; Applying a micro-disturbance signal matching the viscosity characteristics of the electrolyte at the optimal measurement point, wherein the frequency of the micro-disturbance signal corresponds to the characteristic frequency of the electrolyte, to obtain local flow response data of the electrolyte; Analyzing the flow field layering characteristics of the electrolyte under the action of gravity according to the local flow response data, and obtaining the flow velocity distribution and pressure gradient data of the electrolyte at different spatial positions; Based on the flow velocity distribution and pressure gradient data, combined with the viscoelastic properties of the electrolyte, the shear stress distribution of the electrolyte is calculated to obtain flow distribution data; The flow distribution data is subjected to a spatiotemporal evolution analysis to evaluate the flow stability and stratification trend of the electrolyte and obtain evolution data.

5. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 4, characterized in that: The step of applying a micro-disturbance signal matching the viscosity characteristics of the electrolyte at the optimal measurement point, wherein the frequency of the micro-disturbance signal corresponds to the characteristic frequency of the electrolyte, and obtaining local flow response data of the electrolyte comprises: According to the viscosity characteristics of the electrolyte at different temperatures, a temperature compensation type micro-disturbance signal matching the viscosity characteristics is designed, wherein the amplitude of the temperature compensation type micro-disturbance signal is adaptively adjusted as the temperature increases; At the optimal measurement point, based on the compression characteristics of the electrolyte under a high-voltage environment, the frequency response characteristics of the micro-disturbance signal are adjusted to correspond to the characteristic frequency of the electrolyte; In the process of applying the micro-disturbance signal, the local viscosity change of the electrolyte at the optimal measurement point is monitored in real time to obtain viscosity temperature coefficient data; According to the viscosity temperature coefficient data, the shear thinning characteristics and flow response characteristics of the electrolyte are analyzed to obtain local flow response data of the electrolyte.

6. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 1, characterized in that: According to the flow distribution data and the evolution data, a voltage sequence corresponding to the ion characteristics is applied to perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics, including: Based on the flow distribution data and the evolution data, analyzing the difference in flow states of cations and anions in the electrolyte, determining characteristic migration times of different types of ions, and generating a voltage pulse sequence including multiple amplitudes and durations; Under the action of the voltage pulse sequence, transient current response data of the electrolyte is obtained, and migration characteristic parameters of different types of ions are extracted according to the transient current response data; The migration characteristic parameters and the transient current response data are combined to analyze the spatial distribution evolution process of different types of ions to obtain ion distribution characteristics.

7. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 6, characterized in that: The method of obtaining transient current response data of the electrolyte under the action of the voltage pulse sequence, and extracting migration characteristic parameters of different types of ions according to the transient current response data, includes: According to the charge number and ion radius characteristics of various ions in the electrolyte, the migration rate differences of ions in the electric field are analyzed to obtain the ion migration rate distribution data; In each pulse cycle of the voltage pulse sequence, multi-time scale sampling is performed on the transient current response to obtain current response components reflecting different migration time constants; Analyzing the time domain characteristics of the current response component, extracting the peak response time and current decay rate of each type of ion, and obtaining the kinetic response data of ion migration; The migration rate distribution data and the kinetic response data are combined to perform time-resolved analysis on the current contribution of cations and anions to obtain migration characteristic parameters.

8. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 1, characterized in that: The method of performing microstructure analysis under a preset temperature change process according to the ion distribution characteristics to obtain structure change data and dielectric response data includes: According to the ion distribution characteristics, the distribution state of the intermolecular force of the electrolyte is determined, and a temperature change sequence including a heating stage, a constant temperature stage and a cooling stage is designed, wherein the heating rate of the heating stage is 5°C / min, the holding time of the constant temperature stage is 30min, and the cooling rate of the cooling stage is 2°C / min; At each stage of the temperature change sequence, the dielectric loss factor and dielectric constant of the electrolyte are obtained, the temperature sensitivity of the molecular structure of the electrolyte is analyzed, and the structural change data is obtained; Based on the structural change data, the aggregation state and solvation characteristics of the electrolyte molecules are analyzed as a function of temperature, the polarization intensity and relaxation time of the electrolyte at different temperatures are calculated, and the dielectric response data are obtained.

9. The method for evaluating the state of an aluminum electrolytic capacitor according to claim 1, characterized in that: The method of analyzing the change characteristics of the molecular level, bubble distribution and overall performance according to the structural change data and the dielectric response data to obtain the stability evaluation results includes: Based on the structural change data, the aggregation degree and orientation state of the electrolyte molecular chains are analyzed, the change trend of the intermolecular interaction energy is calculated, and the molecular level stability index is obtained; Analyzing the number density, size distribution and growth rate of bubbles in the electrolyte according to the dielectric response data, and establishing bubble evolution characteristic parameters; Combining the molecular level stability index and the bubble evolution characteristic parameter, the dynamic change law of the conductivity, polarization characteristics and dielectric loss of the electrolyte is calculated to construct an overall performance evaluation index; Based on the time evolution characteristics of the overall performance evaluation index, the long-term stability of the electrolyte is evaluated to obtain a stability evaluation result.

10. A state assessment device for an aluminum electrolytic capacitor, characterized in that: include: An interface polarization analysis module is used to perform frequency scanning measurement on the interface between the electrolyte and the oxide film, obtain data on the change of the interface polarization current phase angle with frequency, analyze the interface polarization response based on the change data, and obtain polarization characteristic parameters; A fluid dynamics measurement module, used to measure the fluid dynamics characteristics of the electrolyte, detect micro-flow response characteristics, analyze the flow field distribution state, and obtain flow distribution data and evolution data according to the polarization characteristic parameters; An ion migration analysis module is used to apply a voltage sequence corresponding to the ion characteristics according to the flow distribution data and the evolution data, perform ion migration kinetics analysis, obtain migration response data of different types of ions, and obtain ion distribution characteristics; A microstructure measurement module, used to perform microstructure analysis under a preset temperature change process according to the ion distribution characteristics, and obtain structure change data and dielectric response data; The stability evaluation module is used to analyze the change characteristics of the molecular level, bubble distribution and overall performance according to the structural change data and dielectric response data to obtain a stability evaluation result.

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