Multi-stress battery accelerated aging test method and system

Abstract

The invention relates to the technical field of battery aging test, solves the problems of low accuracy and period of battery aging test in the prior art, and provides a multi-stress battery accelerated aging test method and system, and the method comprises the steps: obtaining a target combination parameter set according to a plurality of stress loading parameters; according to the target combined parameter set, each stress loading parameter is calibrated, and each stress acceleration index is obtained; according to a preset reference stress loading parameter, in combination with each target combination parameter and each stress acceleration index, establishing a multi-stress acceleration factor model; according to a preset original stress loading parameter, correcting the original stress loading parameter to obtain a target stress loading parameter; and according to the target stress loading parameter, in combination with the multi-stress acceleration factor model, performing an accelerated aging test on the target battery to obtain an aging test result. The accuracy of the battery aging test is improved, and the test period is shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery aging test, and particularly relates to a multi-stress battery accelerated aging test method and system. BACKGROUND

[0002] As the core energy unit of today's mobile terminals, electric vehicles and large-scale energy storage systems, the performance degradation and life prediction of lithium batteries are directly related to the vehicle endurance, safety, economy and after-market maintenance cost. Therefore, it is of great practical significance to carry out scientific and reliable lithium battery aging test. First, lithium battery aging test can help the research and development team to accurately evaluate the influence of battery material formula, electrode structure and process parameters on the life in the early design stage, so as to optimize the battery design. Second, through systematic aging data accumulation and analysis, it can provide basis for vehicle manufacturers and energy storage operators to develop reasonable maintenance, battery replacement or step utilization strategy, and reduce the use risk. In addition, the standard aging test system can also provide a unified evaluation standard for industry supervision, standard development and third-party testing institutions, and promote the development of lithium battery life cycle management to be more precise and intelligent. In summary, the establishment of an accelerated aging test method closer to the actual working condition is not only related to product competitiveness and user experience, but also related to the sustainable and healthy development of the entire industry chain.

[0003] At present, lithium battery aging test mostly relies on single stress acceleration method based on Arrhenius model, including high temperature constant temperature / high-low temperature cycle storage test, rate cycle charge-discharge test, etc. This kind of method assumes that the battery aging rate is mainly controlled by a single factor of temperature or current rate, and the Arrhenius acceleration factor is obtained by experiment fitting, and then the test results are mapped to the life prediction under actual use environment. Although this single stress acceleration test has certain advantages in experimental operation convenience and result repeatability, it has three technical bottlenecks in practical application: first, the use of temperature or rate single stress cannot fully simulate the complex effects of temperature, vibration, overcharge / overdischarge and other multiple stress coupling in actual working conditions, resulting in large difference between test conditions and actual use environment; second, the traditional Arrhenius model only considers the influence of single stress such as temperature on chemical / electrochemical reaction rate, and does not fully consider the interaction mechanism between stresses, so that the obtained acceleration factor has significant deviation from the real battery aging behavior; third, due to the lack of parameter optimization mechanism in single stress test itself, the test period still needs several months or even years of experimental verification, which is difficult to meet the demand of rapid iteration of research and development period. The above shortcomings directly restrict the accuracy and efficiency of lithium battery aging life prediction, and it is urgent to introduce multi-stress coupling acceleration test and aging parameter optimization method to improve the test reliability, shorten the test period and better reflect the degradation law of battery in complex use environment.

[0004] How to improve the accuracy of battery aging test and shorten the aging test period under the coupling of multiple stresses is a technical problem to be solved. SUMMARY

[0005] Therefore, embodiments of the present application provide a multi-stress battery accelerated aging test method and system to solve the problem of low accuracy and long period of battery aging test in the prior art.

[0006] In a first aspect, embodiments of the present application provide a multi-stress battery accelerated aging test method, the method comprising: According to a plurality of preset stress loading parameters for battery aging test, a target combination parameter set is obtained; According to the target combination parameter set, each stress loading parameter is calibrated respectively to obtain a stress acceleration index; According to a preset reference stress loading parameter, a multi-stress acceleration factor model is established in combination with each target combination parameter and each stress acceleration index; According to a preset original stress loading parameter, a target battery to be tested is tested, and the original stress loading parameter is corrected according to the test result to obtain a target stress loading parameter; According to the target stress loading parameter, the target battery is subjected to accelerated aging test in combination with the multi-stress acceleration factor model to obtain an aging test result.

[0007] Preferably, the calibration of each stress loading parameter according to each target combination parameter to obtain a stress acceleration index comprises: A preset material constant, a reference vibration life constant and a reference charge-discharge rate life constant are obtained; According to the target combination parameter set, the target battery is tested to obtain a cycle life set of the target battery; According to the cycle life set, the material constant, the reference vibration life constant and the reference charge-discharge rate life constant are combined to calculate each stress acceleration index.

[0008] Preferably, the target combination parameter set comprises a first combination parameter set, a second combination parameter set and a third combination parameter set; the first combination parameter, the second combination parameter and the third combination parameter each comprise a vibration acceleration value, a charge-discharge rate and a temperature value; The vibration acceleration values of each first combined parameter in the first combined parameter set are the same, the charge-discharge rates are the same, and the temperature values are different; the vibration acceleration values of each second combined parameter in the second combined parameter set are different, the charge-discharge rates are the same, and the temperature values are the same; and the vibration acceleration values of each third combined parameter in the third combined parameter set are the same, the charge-discharge rates are different, and the temperature values are the same.

[0009] Preferably, the testing the target battery according to the target combined parameter set to obtain a cycle life set of the target battery comprises: testing the target battery according to the target combined parameter set; obtaining a battery capacity value and a first internal resistance value in the battery testing process according to a preset data acquisition frequency; determining whether a test termination condition is reached according to the battery capacity value and the first internal resistance value in combination with a preset capacity attenuation threshold and a first internal resistance growth rate threshold; when it is determined that the test termination condition is reached, determining the cycle life set according to the number of charge-discharge cycles of the battery in the testing process.

[0010] Preferably, the cycle life set comprises a first cycle life corresponding to each first combined parameter, a second cycle life corresponding to each second combined parameter, and a third cycle life corresponding to each third combined parameter; and the calculation of each stress acceleration index according to the cycle life in combination with the material constant, a reference vibration life constant, and a reference charge-discharge rate life constant comprises: calculating a temperature acceleration index according to each first cycle life and the material constant in combination with each temperature value in the first combined parameter set; calculating a vibration acceleration index according to each second cycle life and the reference vibration life constant in combination with each vibration acceleration value in the second combined parameter set; calculating a charge-discharge rate acceleration index according to each third cycle life and the reference charge-discharge rate life constant in combination with each charge-discharge rate in the third combined parameter set; determining the stress acceleration index according to the temperature acceleration index, the vibration acceleration index, and the charge-discharge rate acceleration index.

[0011] Preferably, the establishment of a multi-stress acceleration factor model according to a preset reference stress loading parameter in combination with each target combined parameter and each stress acceleration index comprises: obtaining a reference temperature value and a reference vibration acceleration value according to the reference stress loading parameter; testing the target battery according to the reference temperature value and the reference vibration acceleration value to obtain a reference cycle life; The reference cycle life and the cycle life set are calculated by using a least square method to obtain an interaction coefficient; According to the interaction coefficient, the reference stress loading parameter, and each stress acceleration index, a multi-stress acceleration factor model is established in combination with each target combination parameter.

[0012] Preferably, the target battery to be tested is tested according to the preset original stress loading parameter, and the original stress loading parameter is corrected according to the test result to obtain the target stress loading parameter, which includes: According to the preset stress loading parameter safety threshold, the original stress loading parameter meeting the battery safety test requirement is obtained; The target battery is tested according to the original stress loading parameter; According to the data acquisition frequency, a plurality of second internal resistance values of the target battery in the test process are obtained; According to adjacent internal resistance values in each second internal resistance value, internal resistance growth rates corresponding to each adjacent internal resistance value are calculated; When a target internal resistance growth rate in each internal resistance growth rate is greater than a preset second internal resistance growth rate threshold, the original stress loading parameter is corrected according to the adjacent internal resistance value corresponding to the target internal resistance growth rate to obtain the target stress loading parameter.

[0013] Preferably, after the target battery is tested for accelerated aging according to the target stress loading parameter in combination with the multi-stress acceleration factor model to obtain an aging test result, it includes: The target stress loading parameter is input into the multi-stress acceleration factor model to obtain a target acceleration factor; The target battery is tested according to the target stress loading parameter to obtain a single cycle time and a target cycle number, wherein the single cycle time includes the time required for the target battery to complete one complete charge-discharge cycle, and the target cycle number includes the number of charge-discharge cycles when the target battery reaches a target aging state; According to the target acceleration factor, in combination with the single cycle time and the target cycle number, an aging equivalent test time is calculated.

[0014] Preferably, when a target internal resistance growth rate in each internal resistance growth rate is greater than a preset second internal resistance growth rate threshold, the original stress loading parameter is corrected according to the adjacent internal resistance value corresponding to the target internal resistance growth rate to obtain the target stress loading parameter, which includes: According to the charging and discharging voltage and current collected in the test process according to the preset data collection frequency, the open circuit voltage change rate in the single battery charging and discharging cycle is calculated, and the target open circuit voltage change rate is obtained; The integral value of the charging and discharging capacity collected in the test process according to the preset data collection frequency is compared with the charging capacity and the discharging capacity, and the target coulomb efficiency of the current charging and discharging cycle is obtained. According to the charging and discharging voltage and capacity data in the test process, differential capacity analysis is performed, and the target differential capacity characteristic change quantity corresponding to the current cycle is obtained. The target open circuit voltage change rate, target coulomb efficiency and target differential capacity characteristic change quantity are compared with the preset open circuit voltage change rate threshold, coulomb efficiency threshold and target differential capacity characteristic change quantity threshold, and it is judged whether there is an abnormal degradation index exceeding the threshold. When the target open circuit voltage change rate is greater than the open circuit voltage change rate threshold, and / or the target coulomb efficiency is greater than the coulomb efficiency threshold, and / or the target differential capacity characteristic change quantity is greater than the target differential capacity characteristic change quantity threshold, the target internal resistance growth rate is calculated according to the adjacent internal resistance value at the current time, and it is judged whether the target internal resistance growth rate exceeds the second internal resistance growth rate threshold. When the target internal resistance growth rate is greater than the second internal resistance growth rate threshold, the original stress loading parameter is modified according to the adjacent internal resistance value corresponding to the target internal resistance growth rate, and the target stress loading parameter is obtained.

[0015] In the second aspect, the embodiments of the present application provide a multi-stress battery accelerated aging test system, comprising: at least one processor, at least one memory and computer program instructions stored in the memory, when the computer program instructions are executed by the processor, the method of the first aspect in the above-mentioned embodiments is realized.

[0016] In summary, the beneficial effects of the present application are as follows: The multi-stress battery accelerated aging test method and system provided by the embodiment of the present application, the method comprises: obtaining a target combination parameter set according to a plurality of preset stress loading parameters for battery aging test; respectively calibrating each stress loading parameter according to the target combination parameter set to obtain a stress acceleration index; establishing a multi-stress acceleration factor model according to a preset reference stress loading parameter, in combination with each target combination parameter and each stress acceleration index; testing a target battery to be tested according to a preset original stress loading parameter, and correcting the original stress loading parameter according to the test result to obtain a target stress loading parameter; and performing accelerated aging test on the target battery according to the target stress loading parameter in combination with the multi-stress acceleration factor model to obtain an aging test result. The embodiment of the present application firstly calibrates a plurality of preset stress loading parameters, respectively calculates the acceleration index of each stress, and constructs a multi-stress acceleration factor model in combination with the preset reference loading parameter and the target combination parameter set; on this basis, the original loading parameter is corrected according to the test result to obtain the target stress parameter that can best reflect the multi-stress coupling effect of the battery under real working conditions; finally, the target stress parameter and the established multi-stress acceleration factor model are used to test the battery. In this way, on the one hand, the multi-stress coupling model can more accurately simulate the interaction of factors such as temperature, stress and current in the actual use environment, thereby significantly improving the accuracy of aging behavior prediction; on the other hand, the test conditions under the joint action of the calibration step and the multi-stress acceleration factor can greatly shorten the experimental period while keeping the result reliable, effectively overcoming the shortcomings of low accuracy and long period of traditional single-stress accelerated test. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows, and other drawings can also be obtained by those of ordinary skill in the art without creative labor on the premise that these drawings do not deviate from the protection scope of the present application.

[0018] Figure 1 is the overall flowchart of the multi-stress battery accelerated aging test method of the embodiment 1 of the present application; Figure 2 is the structural block diagram of the multi-stress battery accelerated aging test system of the embodiment 2 of the present application. DETAILED DESCRIPTION

[0019] The features and exemplary embodiments of the various aspects of the present application will be described in detail below with reference to the drawings. In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are configured only to explain the present application and are not configured to limit the present application. The present application can be implemented without some of these specific details by those skilled in the art. The following description of the embodiments is merely to provide a better understanding of the present application by showing examples of the present application.

[0020] It should be noted that, in this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by the phrase "comprising a... " does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0021] It should be noted that all actions of acquiring signals, information or data in the present application are carried out in compliance with the corresponding data protection regulations and policies of the place and with the authorization given by the owner of the corresponding device.

[0022] Embodiment 1 See Figure 1 The embodiment of the present application provides a multi-stress battery accelerated aging test method, which comprises the following steps: According to a plurality of preset stress loading parameters for battery aging test, a target combination parameter set is acquired; Specifically, according to a plurality of preset stress loading parameters for battery aging test, the stress loading parameters include temperature, vibration and charge-discharge rate, wherein the temperature, vibration and charge-discharge rate respectively refer to thermal stress, mechanical vibration stress and electrochemical rate stress applied in the accelerated aging test, for example, the temperature level can be set to 25 °C, 45 °C and 55 °C; the vibration level can be selected as 1 g, 10 g and 15 g; the charge-discharge rate can be set to 1 C, 1.5 C and 2 C; by setting three levels for the above three stress loading parameters, 9 groups of accelerated aging combinations are generated, and the target combination parameter set is obtained.

[0023] According to the target combination parameter set, each stress loading parameter is calibrated respectively to obtain a stress acceleration index; Specifically, according to the target combination parameter set, each stress loading parameter is calibrated respectively to obtain a stress acceleration index, wherein the calibration process includes, for each stress loading parameter, keeping other stress loading parameters at a reference state and changing the level of the stress loading parameter respectively, measuring battery performance degradation data and fitting to obtain the function relationship between the acceleration index corresponding to the stress and the stress level. The purpose of this step is to quantify the contribution of each single stress to the battery aging rate, and to provide accurate single-factor acceleration parameters for the subsequent multi-stress coupling acceleration factor model.

[0024] Preferably, the calibration of each stress loading parameter according to the target combination parameter set to obtain a stress acceleration index comprises: Obtaining a pre-set material constant, a reference vibration life constant and a reference charge-discharge rate life constant; Specifically, the preset material constant, the reference vibration life constant and the reference charge-discharge rate life constant are obtained, the material constant includes a quantitative parameter related to the aging mechanism of the positive and negative active materials or the separator material of the battery, such as activation energy (Ea) and proportional factor (A) for describing the chemical reaction rate, which can be obtained by literature search or differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS) analysis; the reference vibration life constant refers to the average failure cycle number measured when the same type of battery is tested under a certain specified vibration level (for example, 5 g, 10 Hz mechanical vibration condition), which is used to represent the baseline effect of vibration stress on the fatigue degradation of the battery structure; the reference charge-discharge rate life constant refers to the cycle number experienced by the battery under test from full charge to capacity attenuation to 80% under the standard condition of 1 C rate (i.e. charging and discharging once in 1 hour according to the rated capacity), which can be obtained by performing charge-discharge fatigue test on the prototype in a constant temperature and humidity environment and taking the average value. The purpose of this step is to provide necessary reference and calibration basis for subsequent multi-stress acceleration model: on the one hand, the material constant can be used to predict the order of magnitude of the temperature acceleration factor; on the other hand, the reference vibration and rate life constants can be used as the calibration starting point of the vibration and rate single stress acceleration model, respectively, so as to ensure the unified dimension and comparability of the subsequent single stress and interaction effect calculation. In specific implementation, first, the material activation energy and pre-factor of the same batch of battery model are obtained through literature search or manufacturer's technical manual; then, at least 5 prototypes are tested in parallel under the conditions of no vibration, 1 C rate and 25 °C, and the cycle number when the capacity attenuation is 80% is counted, and the average value is taken as the reference charge-discharge rate life constant; then, under the same environmental temperature, the same batch of batteries are subjected to fatigue cycle by using a sine vibration table with a set vibration amplitude (such as 5 g, 10 Hz), and the average cycle failure number is recorded under the same termination condition to obtain the reference vibration life constant. Combined with the material constant and reference life constant acquisition technology of this step, accurate initial parameters can be provided for the multi-stress coupling model, so that the acceleration index and life prediction obtained through single factor and multi-factor calibration have higher physical consistency and reliability, thereby reducing the model error caused by parameter mismatch.

[0025] According to the target combination parameter set, the target battery is tested to obtain a cycle life set of the target battery; Specifically, according to the target combination parameter set, a cycle life set of the target battery is obtained; the target combination parameter set refers to a combination of multiple stress loading parameters selected in previous orthogonal screening or design optimization and capable of representing typical actual working conditions; and the cycle life set refers to cycle number data collected for each group until the capacity decays to a preset termination threshold (such as 80%) or the internal resistance increases to a warning value, when the same batch of batteries is respectively subjected to cycle charging and discharging tests under each target combination condition. The purpose of this step is to obtain real data of the actual aging rate of the battery under the parameter combination by actually measuring the target battery in the specific multi-stress environment corresponding to the target combination parameter set, so as to provide reliable samples for fitting and verification of each factor and its interaction term in the multi-stress acceleration model. On the one hand, by actually measuring the cycle life under the target combination, the deviation caused by pure empirical speculation can be significantly reduced, and the prediction accuracy of the acceleration model for battery degradation under complex use scenarios can be improved; on the other hand, since only a limited number of typical combinations need to be tested (rather than all extreme cases), the test period can be significantly shortened under the premise of ensuring the reliability of the results, thereby saving a large amount of time and cost for subsequent acceleration model verification and optimization.

[0026] Preferably, the testing of the target battery according to the target combination parameter set to obtain a cycle life set of the target battery comprises: testing the target battery according to the target combination parameter set; Specifically, the target combination parameter set refers to a typical temperature, vibration and rate ternary combination under actual working conditions obtained after previous screening or design optimization, such as temperature 55 °C, vibration 10 g / 15 Hz, rate 2 C, etc. According to the target combination parameter set, actual operation tests are performed on the battery in the target multi-stress environment to obtain real performance degradation data, thereby providing a reliable experimental basis for subsequent fitting and verification of the acceleration model. In the implementation process, the battery to be tested is placed on a multi-condition test table capable of simultaneously applying temperature, vibration and charging and discharging rate, the temperature box is preheated to a preset temperature, the vibration table is started to apply mechanical vibration with a corresponding amplitude and frequency, and a constant current charging and discharging tester is used to perform cycle charging and discharging on the battery at a set rate. The entire test process must maintain stable and synchronous operation of each parameter to ensure that the temperature, vibration and rate are always consistent within the same cycle. Since this step uses multi-factor collaborative loading technology, the test is closer to the actual use scenario, and the degradation data obtained will be more representative, which helps to improve the prediction accuracy of the subsequent model for battery aging characteristics in complex working conditions.

[0027] According to a preset data acquisition frequency, the battery capacity value and the first internal resistance value in the battery test process are obtained; Specifically, the data collection frequency refers to the time interval for sampling the key performance parameters of the battery during the test process, such as collecting once every 10 cycles or every 50 cycles; the battery capacity value is usually the discharge ampere-hour (Ah) measured in a certain discharge cycle, which reflects the remaining available energy of the battery; and the first internal resistance value refers to the direct current internal resistance (DCIR) measured by a constant current discharge or an alternating current impedance test at a specific time during the charge and discharge process, which can be used to characterize the increase of the internal impedance of the battery with aging. The purpose of this step is to record the performance change curve of the battery under multi-stress loading in real time, so as to accurately master the decline speed and failure evolution. In specific implementation, after completing N charge and discharge cycles, the program automatically pauses the charge and discharge (constant current discharge for 1 s or a small current pulse), measures and records the remaining capacity of the battery and the direct current internal resistance calculated by the instantaneous terminal difference method after discharging, and obtains a more delicate aging curve through high-frequency data collection and accurate capacity and impedance measurement technology, which helps to quickly identify the inflection point of battery decline and provides sufficient data support for period determination and model fitting.

[0028] According to the battery capacity value and the first internal resistance value, in combination with a preset capacity attenuation threshold and a first internal resistance growth rate threshold, it is determined whether a test termination condition is reached. Specifically, the capacity attenuation threshold is usually set to 80% of the initial design capacity (for example, 1 Ah) (i.e., when the remaining available capacity of the battery is less than 0.8 Ah, it is considered to have failed); and the first internal resistance growth rate threshold can be defined as an increase of 50% or a doubling (e.g., increasing to 75 mΩ or 100 mΩ is considered to be critical) relative to the initial direct current internal resistance (e.g., 50 mΩ), which is used to determine whether the internal impedance of the battery has reached an irreversible increase level. In the implementation process, after each data collection, the collected capacity value is first compared with the capacity attenuation threshold. If it has fallen below the set threshold, it is immediately marked as reaching the failure condition, i.e., reaching the test termination condition; if the capacity has not yet reached the failure threshold, the ratio of the current internal resistance value to the initial first internal resistance value also needs to be calculated. If the first internal resistance growth rate exceeds the set threshold (e.g., the growth rate is greater than or equal to 50%), it is also determined that the test termination condition is reached. In addition, the data of more than two consecutive times can be confirmed to avoid misjudgment due to measurement noise or accidental abnormalities. Through this double-threshold determination technical feature, the moment when the battery enters irreversible failure can be captured earlier and more accurately, so as to ensure that the obtained cycle life data is not only reliable but also has physical meaning.

[0029] When it is determined that the test termination condition is reached, the cycle life set is determined according to the number of charge and discharge cycles of the battery during the test process.

[0030] Specifically, the number of charge-discharge cycles refers to the total number of discharge-charge or charge-discharge reciprocating cycles completed by the battery from the start of the test to the triggering of the above termination condition; the main purpose of this step is to extract and record the actual cycle life of each battery under the target combined test under the premise of ensuring the accuracy of the failure judgment, forming a life set that can reflect individual differences and experimental errors. In specific implementation, when a certain test unit is determined to reach the failure threshold, the system automatically records the cumulative cycle number of the battery and archives it together with the test conditions (temperature, vibration, and rate); at the same time, the same collection and judgment method is continued for other batteries in the same group until all samples meet the failure condition, and the cycle numbers of the batteries are sorted into an array or table, which is the cycle life set. By using the failure cycle number recording technology of this step, the life differences between different samples caused by process, material batch, or measurement deviation under the same multi-stress combination can be intuitively reflected, and a statistical basis is provided for subsequent calculation of the acceleration index. Through the life data of batch samples, the life distribution and uncertainty can be estimated, and the robustness and generalization ability of the acceleration model are enhanced.

[0031] According to the cycle life set, the material constant, the reference vibration life constant, and the reference charge-discharge rate life constant, the stress acceleration indexes are calculated.

[0032] Specifically, the stress acceleration index is used to quantify the acceleration multiple of the battery aging rate under a given single variable stress condition relative to the reference condition (such as 25 °C, 0 g vibration, and 1 C rate); by comparing the cycle life set obtained under the combination of the actual test multi-stress loading parameters with the life value theoretically or empirically calculated based on the material constant, the reference vibration life constant, and the reference charge-discharge rate life constant, the stress acceleration indexes corresponding to the temperature, vibration, and rate three stress loading parameters are deduced.

[0033] Preferably, the cycle life set includes first cycle lives corresponding to the first combination parameters, second cycle lives corresponding to the second combination parameters, and third cycle lives corresponding to the third combination parameters; and the calculation of the stress acceleration indexes according to the cycle life set, the material constant, the reference vibration life constant, and the reference charge-discharge rate life constant includes: According to the first cycle lives and the material constant, the temperature acceleration indexes are calculated in combination with the temperature values in the first combination parameter set; Specifically, the first cycle life refers to the number of cycles to failure measured when only the temperature condition is changed while keeping other stresses (such as vibration acceleration, charge-discharge rate) as the baseline state (e.g., 0 g vibration, 1 C rate) for the target battery during cycle testing; the material constants include Arrhenius model parameters related to temperature sensitivity, such as activation energy (Ea) and pre-exponential factor (A), which are usually obtained through differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS) and the like, for describing the variation of chemical reaction rate of battery materials at different temperatures; each temperature value in the first set of combined parameters refers to a number of temperature levels in an orthogonal test or pre-designed, such as temperature values set to 25°C, 45°C, 55°C and 65°C, etc. By comparing the cycle life actually tested at different temperatures with the life at the baseline temperature, and calculating the temperature acceleration index based on the temperature-dependent model established by the material constants, the independent contribution of temperature to the aging rate of the battery under stress is quantified. In specific implementation, first, the same batch of batteries are placed in a set temperature box under constant vibration (0 g) and rate (1 C) conditions, and the cycle life (to capacity decay to 80% or internal resistance growth to meet the threshold) at each temperature level is recorded according to the preset data collection frequency; then, the temperature acceleration index is calculated using the following formula : wherein, is each of the first cycle life at different temperatures, A is a material constant, and T is each temperature value in the first set of combined parameters actually loaded.

[0034] According to each of the second cycle life and the baseline vibration life constant, in combination with each vibration acceleration value in the second set of combined parameters, a vibration acceleration index is calculated. Specifically, the second cycle life refers to the number of cycles to failure measured by performing a cycle test on the target battery under the condition that only the vibration condition is changed, the temperature (25°C) and the rate (1C) are kept as the baseline state; the baseline vibration life constant refers to the average number of cycles to failure obtained by testing the same model battery under a pre-set reference vibration condition (for example, 5 g, 10 Hz sinusoidal vibration), which is usually obtained by averaging multiple repeated tests; and each vibration acceleration value in the second set of combined parameters represents a vibration level to be calibrated, such as 1 g, 10 g, 15 g, 20 g, etc. The purpose of this step is to quantify the contribution of mechanical vibration to the fatigue damage of the electrode structure and the adhesive layer inside the battery under stress, and to obtain the vibration acceleration index by calculating the ratio of the cycle life measured under different vibration levels to the baseline vibration life. In the implementation process, the same batch of batteries are first placed on a vibration table under constant temperature (25°C) and constant rate (1C) conditions, and are sequentially loaded with vibration levels of 1 g / 10 Hz, 10 g / 10 Hz, 15 g / 10 Hz and 20 g / 10 Hz, etc. The number of cycles to failure is collected at preset intervals; after obtaining the second cycle life under each vibration condition, it is compared with the "baseline vibration life constant", that is, the vibration acceleration index is calculated using the following formula : wherein, is the cycle life under different vibrations, B is the baseline vibration life constant (the theoretical life when V = 1 g), is the actual loaded vibration acceleration value in the second set of combined parameters.

[0035] According to the third cycle life and the baseline charge-discharge rate life constant, the charge-discharge rate acceleration index is calculated in combination with each charge-discharge rate in the third set of combined parameters; Specifically, the third cycle life represents the number of cycles to failure measured by cycling test on the battery while only changing the charge-discharge rate (such as 1 C, 1.5 C, 2 C, 2.5 C) and keeping the temperature (25 °C) and vibration (0 g) as the baseline conditions; the baseline charge-discharge rate life constant refers to the average number of cycles obtained by cycling test on the same batch of batteries at 1 C rate (baseline rate) and until the capacity attenuation is 80%; each charge-discharge rate in the third set of combined parameters represents a different rate multiple value, such as 1 C, 1.5 C, 2 C, 2.5 C, etc. By controlling the rate change, the accelerated aging effect caused by polarization effect and uneven lithium deposition / exfoliation of the battery at different rates is objectively quantified, and the charge-discharge rate acceleration index is calculated by comparing the baseline rate life. In specific implementation, first, under constant temperature (25 °C) and constant vibration (0 g) conditions, the same batch of batteries are cycled at 1 C, 1.5 C, 2 C and 2.5 C rates, respectively, the same data collection frequency as before is used to record the changes of capacity and internal resistance, and the third cycle life of the battery at each rate is measured; then, the ratio of the baseline rate life constant (average life under 1 C condition) to the target rate life is calculated, i.e. the charge-discharge rate acceleration index is calculated using the following formula : wherein, is the cycle life under different vibrations, K is the life constant under 1 C charge-discharge rate, is the actual loaded each charge-discharge rate in the first set of combined parameters.

[0036] According to the temperature acceleration index, the vibration acceleration index and the charge-discharge rate acceleration index, the stress acceleration indexes are determined.

[0037] Preferably, the target set of combined parameters includes the first set of combined parameters, the second set of combined parameters and the third set of combined parameters; the first combined parameter, the second combined parameter and the third combined parameter each include a vibration acceleration value, a charge-discharge rate and a temperature value; The vibration acceleration values of each first combined parameter in the first set of combined parameters are the same, the charge-discharge rates are the same and the temperature values are different; the vibration acceleration values of each second combined parameter in the second set of combined parameters are different, the charge-discharge rates are the same and the temperature values are the same; the vibration acceleration values of each third combined parameter in the third set of combined parameters are the same, the charge-discharge rates are different and the temperature values are the same.

[0038] According to the preset baseline stress loading parameters, in combination with each target combined parameter and each stress acceleration index, a multi-stress acceleration factor model is established; Preferably, the step of establishing a multi-stress acceleration factor model according to the preset reference stress loading parameters, in combination with each of the target combination parameters and each of the stress acceleration indices comprises: According to the reference stress loading parameters, a reference temperature value and a reference vibration acceleration value are obtained; Specifically, the reference stress loading parameters refer to the temperature and vibration conditions preset for comparison before the model is established, for example, the preset reference stress loading parameters are ℃, , and so on. The reference temperature value is taken as the reference temperature value, and the reference vibration acceleration value is taken as the reference vibration acceleration value, which are used to compare the performance changes of the battery under different stresses in subsequent tests. By specifying the baseline working condition required for model calibration, a stable reference point is provided for subsequent quantification of each single stress and interaction effect, thereby ensuring that the calculated interaction coefficients and acceleration factors have comparability and physical meaning.

[0039] According to the reference temperature value and the reference vibration acceleration value, a target battery is tested to obtain a reference cycle life; Specifically, the reference cycle life refers to the complete number of charge and discharge cycles experienced by the target battery under the reference temperature and reference vibration conditions from the first full capacity to the capacity attenuation to 80% or the internal resistance growth exceeding the set threshold. The purpose of this step is to obtain a basic reference life value for comparison with the multiple combination working condition data in the cycle life set by repeatedly testing the target battery under the reference working condition, so as to serve as a reference vector for subsequent fitting of the interaction coefficients. In specific implementation, the battery to be tested should be placed in a pre-calibrated environmental test chamber, so that its temperature is stabilized at the reference temperature value (such as 25°C), and the vibration table is kept at the reference vibration acceleration (such as 1g), and then a constant current charge and discharge tester is used to perform cyclic charge and discharge on the battery at a rate of 1C. During the test, the data acquisition frequency (for example, record the capacity and internal resistance value once every 50 cycles) is consistent with the other combination parameters, and when the capacity is measured to be lower than 80% or the internal resistance increment exceeds 50%, the current cycle number is immediately recorded as the reference cycle life of the battery; the process is repeated for multiple batteries of the same batch to obtain a set of reference life data. The technical feature of this step is to ensure that the reference cycle life data has good repeatability and truly reflects the cycle number corresponding to the intrinsic aging rate of the battery under the action of no additional coupled stress, by strictly controlling the reference working condition and unifying the failure judgment standard; it provides a clear reference baseline for the calculation of the interaction coefficients in the least squares method, avoiding the deviation of the model parameters caused by unstable reference data.

[0040] The reference cycle life and the cycle life set are calculated using the least squares method to obtain interaction coefficients; Specifically, the least square method is a statistical method for solving linear or nonlinear model parameters by minimizing the sum of squares of prediction errors and true observation errors, the cycle life set refers to the cycle life measured for the battery under different target combination parameters, and the interaction coefficient is used to quantify the additional contribution of the mutual influence between temperature and vibration to the battery aging under the action of multiple stress coupling. For example, when the temperature and vibration are simultaneously increased, the actual life is lower than the theoretical life obtained by simply multiplying the respective acceleration indexes, and a negative interaction coefficient needs to be introduced to correct. The purpose of this step is to map the reference cycle life and the life data under multiple factor combinations into an acceleration model containing an interaction term through mathematical fitting, so as to obtain the optimal coefficients of each coupling term, thereby improving the restoration degree of the acceleration model to the real influence of multiple stresses. The interaction coefficient is calculated by using the following formula : is the cycle life of the battery under the reference working condition and ; and is each cycle life in the cycle life set.

[0041] According to the interaction coefficient, the reference stress loading parameter and each stress acceleration index, a multiple stress acceleration factor model is established in combination with each target combination parameter.

[0042] Specifically, each stress acceleration index, interaction coefficient and reference stress loading parameter are organically integrated into the same model to obtain a multiple stress acceleration factor model, so that when any temperature value T, vibration acceleration value V and charge / discharge rate C are given, the corresponding acceleration factor AF can be directly calculated by the model, thereby mapping the accelerated life of the battery under the multiple stresses to the reference life. The established multiple stress acceleration factor model is as follows: , , is each stress acceleration index, is the temperature-vibration interaction coefficient. T is the actual temperature value in the test, is the reference temperature value, V is the actual vibration acceleration value in the test, is the reference vibration acceleration value. C is the actual charge rate applied in the test, ​​The base reference charge and discharge rate; in practical applications, this model can be deployed in a simulation or test system, and when a user inputs a specific combination, the predicted life scaling factor or equivalent base cycle life can be output in real time. The multi-element index coupling and exponential function correction technology features combined with this step can not only reflect the influence of single stress on battery aging rate, but also reflect the nonlinear amplification or inhibition effect of factor coupling through the interaction coefficient, thereby significantly improving the reliability and accuracy of battery life prediction in complex use environments and reducing the cost of manpower and resources required for large-scale experimental verification.

[0043] According to the preset original stress loading parameter, the target battery to be tested is tested, and the original stress loading parameter is corrected according to the test result to obtain a target stress loading parameter; Preferably, the original stress loading parameter is corrected according to the test result to obtain a target stress loading parameter. According to the preset stress loading parameter safety threshold, the original stress loading parameter meeting the battery safety test requirement is obtained; Specifically, the preset stress loading parameter safety threshold usually refers to the upper limit of each stress load specified by the battery manufacturer or industry standard, such as the maximum allowable temperature (such as ), the maximum mechanical vibration acceleration (such as ), and the maximum charge and discharge rate (such as ) and the like. Before running, the thermal runaway temperature, vibration resistance of the adhesive material, and the maximum safety rate of the battery cell in the battery model manual need to be carefully checked. First, limit all temperature, vibration and rate stress conditions in the safety interval that does not cause battery thermal runaway, internal short circuit or structural damage, to ensure that subsequent tests can both reflect the effect of accelerated aging and will not cause battery instantaneous failure or safety accidents due to excessively high parameters. First, read the maximum working temperature and maximum bearing vibration amplitude of each battery material, as well as the maximum current limit of the tab and pole; then set the temperature threshold to , the vibration acceleration threshold to , and the charge and discharge rate threshold to to prevent battery safety accidents; finally, lock these thresholds in the experimental control system and obtain the original stress loading parameter meeting the battery safety test requirement. Combined with the safety constraint technology features of this step, the effect of the initial stress on battery aging can be maximized under the premise of ensuring test safety, which has the beneficial effect of avoiding the risk of sudden failure caused by directly using excessively high working conditions, and providing a reliable baseline for subsequent gradual adjustment of parameters and accurate determination of internal resistance changes.

[0044] According to the original stress loading parameter, the target battery is tested; Specifically, the original stress loading parameter refers to a temperature, a vibration and a rate triplet that can preliminarily stimulate the battery aging within the safety threshold range, for example, a temperature of 45 ℃, a vibration of 8 g / 20 Hz and a rate of 1.5 C; and the target battery refers to a battery sample or module to be evaluated for its life characteristics and subjected to an accelerated aging test. Through the original stress loading parameter, the target battery is subjected to actual cycle testing under safe and controllable initial stress conditions, so as to verify the basic aging trend of the battery under the initial working condition and provide first-hand data for subsequent internal resistance dynamic monitoring and parameter correction. The target battery is placed in an environmental test chamber, and the temperature is quickly stabilized to 45 ℃; at the same time, a vibration table is started to apply mechanical vibration under the parameters of 8 g / 20 Hz; then a constant current charge and discharge tester is started to perform standard cycles at a rate of 1.5 C (for example, 1 C charging to full and discharging to 3.0 V, and then 1 C charging to full), and a data acquisition frequency consistent with the subsequent steps (for example, collecting data once every 10 cycles) is set. The temperature, vibration and rate should be kept stable during the whole test process until the subsequent determination condition is reached or the collection is manually paused. The multi-working condition synchronous loading technology feature of this step can implant sufficient aging stress in a short time, so as to directly show the early degradation characteristics of the target battery under the comprehensive conditions, and the beneficial effects are that the initial change trend of the battery capacity and internal resistance is accelerated, which lays a solid foundation for subsequent fine parameter adjustment and model fitting.

[0045] According to the data acquisition frequency, a plurality of second internal resistance values of the target battery in the test process are obtained; Specifically, the data acquisition frequency refers to the interval setting of automatically pausing the charging and discharging and measuring the internal resistance of the battery during the charging and discharging cycle process, for example, acquiring the voltage and temperature at 1 Hz, acquiring the vibration acceleration at 5 KHz, and acquiring the internal resistance value once every 50 cycles. The second internal resistance value refers to the direct current internal resistance data obtained by each measurement of the target battery under multiple stresses, in units of Ω or mΩ, reflecting the trend of gradually increasing battery internal resistance with aging. By capturing the internal resistance evolution curve of the battery under the initial test working condition at a high frequency and continuously, the abnormal rise can be found in time, and accurate data can be provided for subsequent internal resistance growth rate judgment. In the constant current charging and discharging tester and battery test software started in the previous step, the data acquisition frequency is set to automatically cut off the output and trigger the internal resistance test module (such as pulse discharge method, four-wire method or alternating current impedance test method) after running 50 complete charging and discharging cycles, measure and record the second internal resistance value at the current time; then resume the cycle charging and discharging, and repeat the process until the test is completed or enter the subsequent correction process. By using the timing and automatic internal resistance measurement technology features, the data acquisition interval can be finely corresponded to the aging process, and the timing error caused by manual intervention can be avoided, which has the beneficial effect of accurately depicting the early internal resistance rise rate, and providing detailed and reliable quantitative basis for subsequent judgment of whether the stress is excessive and parameter correction.

[0046] According to adjacent internal resistance values in each of the second internal resistance values, an internal resistance growth rate corresponding to each adjacent internal resistance value is calculated; Specifically, the adjacent internal resistance value refers to the numerical pair between the measurement results of the adjacent two times, such as the direct current internal resistance value of the battery measured at the 50th charging and discharging cycle and the direct current internal resistance value of the battery measured at the 100th charging and discharging cycle; the internal resistance growth rate refers to the percentage or absolute increment of the internal resistance value in the adjacent measurement interval relative to the previous measurement value. For example, if the 50th internal resistance is 50 mΩ and the 100th internal resistance is 55 mΩ, the internal resistance growth rate in this interval can be expressed as (55 mΩ - 50 mΩ) / 50 mΩ = 10%. The purpose of this step is to differentiate the continuous internal resistance data into a measurable growth rate index, so as to facilitate the judgment of whether the battery enters the rapid decline stage by comparing with the preset threshold. In the implementation process, the "multiple second internal resistance value" list recorded in the previous step should be traversed, and the i-th measurement value R i and the (i+1)th measurement value R i+1 are taken out in turn, according to the formula: growth rate i = (R i+1 -R i ) / R i × 100% Calculate the internal resistance growth rate of each measurement interval; combined with the continuous difference calculation technology, the original internal resistance curve can be condensed into a set of comparable growth rate indicators to intuitively quantify the battery's loss trend under the current stress. If the growth rate abnormally increases in a certain period, it indicates that the stress combination has been too aggressive or the internal structure of the battery has suffered irreversible damage, providing accurate nodes for subsequent dynamic adjustment.

[0047] When a target internal resistance growth rate greater than a preset second internal resistance growth rate threshold appears in each of the internal resistance growth rates, the original stress loading parameter is modified according to the adjacent internal resistance value corresponding to the target internal resistance growth rate, to obtain the target stress loading parameter.

[0048] Specifically, the preset second internal resistance growth rate threshold is generally set to the maximum acceptable internal resistance growth rate, for example, set to 2%. When the internal resistance growth rate exceeds this threshold, it is considered that the battery has a significant risk of accelerated degradation and the stress needs to be reduced; the target internal resistance growth rate is the first or any time the growth rate exceeds the threshold in a measurement interval; the modification of the original stress loading parameter is to moderately reduce one or more of the temperature, vibration or rate values, thereby obtaining a target stress loading parameter that is more in line with the battery's bearing capacity under the premise of safety. After real-time monitoring of the abnormal rise of the battery internal resistance, timely dynamic correction of the loading conditions is performed to avoid excessive aggravation of battery aging or safety hazards during testing. When a target internal resistance growth rate greater than a preset second internal resistance growth rate threshold appears in each of the internal resistance growth rates, the adjacent two internal resistance measurement values corresponding to the target internal resistance growth rate are first found, and then the following formula is used to form a new target stress loading parameter: wherein, represents the temperature sensitivity, which is the partial derivative of the acceleration factor AF with respect to the temperature T, indicating the change trend of AF when the temperature rises; represents the vibration sensitivity, which is the partial derivative of the acceleration factor AF with respect to the vibration V, indicating the change trend of AF when the vibration increases; represents the charge-discharge rate sensitivity, which is the partial derivative of the acceleration factor AF with respect to the charge-discharge rate C, indicating the change trend of AF when the rate increases; , , respectively represent the target temperature value, the target vibration acceleration value and the target charge-discharge rate in the target stress loading parameter; , and respectively represent the original temperature value, the original vibration acceleration value and the original charge-discharge rate in the original stress loading parameter; represents the measurement difference between the adjacent two resistance measurements corresponding to the target resistance growth rate; represents the multi-stress acceleration factor calculated by inputting the original stress loading parameter into the multi-stress acceleration factor model; the sign() function is used to determine the sign of a number: return 1 when the input is positive, return -1 when the input is negative, and return 0 when the input is 0; the real-time feedback control based on the resistance growth rate threshold can realize closed-loop adjustment of stress loading, significantly reduce the damage risk of battery structure under over-activation working conditions, and has the beneficial effects of ensuring the continuity and acceleration effect of the test, and timely curbing uncontrolled decline, thereby maximizing the remaining test period and ensuring the effectiveness and safety of the data.

[0049] Preferably, when a target resistance growth rate greater than a preset second resistance growth rate threshold appears in each of the resistance growth rates, the original stress loading parameter is modified according to the adjacent resistance value corresponding to the target resistance growth rate, to obtain the target stress loading parameter. According to the charge-discharge voltage and current collected during the test process according to the preset data collection frequency, the open-circuit voltage change rate in a single battery charge-discharge cycle is calculated to obtain a target open-circuit voltage change rate; Specifically, during the battery charge-discharge test process, complete single charge-discharge voltage curves are collected according to the set voltage and current sampling frequency (such as 1 Hz). By extracting the voltage platform value in the resting state (i.e. the current tends to 0A) during the charge-discharge process, combined with the average open-circuit voltage (OCV) of multiple resting points before and after, the change trend of the open-circuit voltage between multiple charge-discharge cycles is calculated. Further, through linear regression or difference method, the target open-circuit voltage change rate in the current charge-discharge cycle is obtained. This change rate reflects the polarization degree and reversible reaction loss of the battery, and has high sensitivity to the judgment of the battery health state, especially in the early aging stage.

[0050] The integral value of the charge-discharge capacity collected during the test process according to the preset data collection frequency is compared with the charge capacity and the discharge capacity to obtain a target coulomb efficiency of the current charge-discharge cycle; Specifically, according to the current data collected in real time during the test process, the single complete charging process and the discharging process are integrated respectively to obtain the charging capacity (Q_charge) and the discharging capacity (Q_discharge). The ratio of the two is calculated to obtain the coulomb efficiency η = Q_discharge / Q_charge of the period. It is defined as the target coulomb efficiency of the period. The decrease in coulomb efficiency is usually caused by irreversible reactions such as the enhancement of side reactions or the loss of active lithium, and is an important indicator for measuring the stability of the battery and the strength of the side reaction. By comparing the target coulomb efficiency with the preset efficiency threshold (such as 98%, 95%, etc.), degradation abnormalities can be detected in time when the main performance has not yet decreased significantly.

[0051] According to the charging and discharging voltage and capacity data during the test process, the differential capacity analysis is performed to obtain the target differential capacity characteristic change quantity corresponding to the current cycle; Specifically, using the charging and discharging voltage-capacity curve data collected in each cycle, the derivative of voltage with respect to capacity (i.e. dQ / dV curve) is calculated by using the numerical differentiation method. The characteristic peaks (such as the height, position and shape of the main reduction peak and the main oxidation peak) in the differential capacity curve are extracted and compared with the reference characteristics of the initial state or the previous several cycles to obtain the target differential capacity characteristic change quantity Δ(dQ / dV) corresponding to the current charging and discharging cycle. The characteristic change can be used to identify the structural change of the electrode material, the lithium ion transmission blockage and other deep-level aging mechanisms, and has important significance for revealing structural degradation and phase change.

[0052] The target open-circuit voltage change rate, the target coulomb efficiency and the target differential capacity characteristic change quantity are compared with the preset open-circuit voltage change rate threshold, the coulomb efficiency threshold and the target differential capacity characteristic change quantity threshold to determine whether there is an abnormal degradation index exceeding the threshold; Specifically, the target open-circuit voltage change rate, the target coulomb efficiency and the target differential capacity characteristic change quantity obtained above are compared with the corresponding preset thresholds respectively to determine whether there is any abnormal degradation phenomenon exceeding the threshold in the current cycle. This multi-dimensional judgment method is better than a single capacity or internal resistance indicator and can more comprehensively capture the aging trend. The judgment logic can use Boolean logic or relationship, that is, when any one of the indicators exceeds the preset threshold, it is determined that there is a degradation anomaly in the current cycle, triggering the subsequent correction mechanism.

[0053] When the target open-circuit voltage change rate is greater than the open-circuit voltage change rate threshold, and / or the target coulomb efficiency is greater than the coulomb efficiency threshold, and / or the target differential capacity characteristic change quantity is greater than the target differential capacity characteristic change quantity threshold, the target internal resistance growth rate is calculated according to the adjacent internal resistance value at the current time, and it is determined whether the target internal resistance growth rate exceeds the second internal resistance growth rate threshold; Specifically, on the basis of any degradation index abnormal triggering, further combined with the adjacent two times of resistance measurement results (every 50 times of collection), the target resistance growth rate is calculated. If the target resistance growth rate exceeds the second resistance growth rate threshold (such as 2%), it is determined that the degradation is a substantial impact aging trend, providing a qualitative or quantitative basis for subsequent stress loading parameter adjustment, and improving the active control ability and prediction accuracy of the test process.

[0054] When the target resistance growth rate is greater than the second resistance growth rate threshold, the original stress loading parameter is modified according to the adjacent resistance value corresponding to the target resistance growth rate, and the target stress loading parameter is obtained.

[0055] According to the target stress loading parameter, combined with the multi-stress acceleration factor model, the target battery is subjected to accelerated aging test, and the aging test result is obtained.

[0056] Specifically, the target stress loading parameter refers to the loading combination of temperature, vibration acceleration and charge-discharge rate finally determined through the foregoing modification process, that is 、 、 , and the multi-stress acceleration factor model is a mathematical expression containing temperature index, vibration index, rate index and their interaction coefficients obtained by least squares fitting, which is used to map the coupling effect of the three into a comprehensive acceleration multiple. Under the guidance of the comprehensive acceleration model, according to the target stress loading parameter, the target battery is subjected to multi-stress acceleration test, so that the experimental results can reflect the synergistic degradation effect of temperature, vibration and rate, and the accuracy and reliability of the model are further verified by comparing with the predicted results. In specific implementation, the environmental test chamber in the test system should be preheated or kept at the target temperature , the vibration table is started to apply mechanical vibration under the setting, and the constant current and constant voltage charge-discharge test equipment is used to cycle the battery at the charge-discharge rate; in this process, the degradation indexes such as battery capacity and resistance are recorded synchronously according to the preset data acquisition frequency, until the determination condition is triggered (such as the capacity attenuation to 80% or the resistance growth rate exceeding the threshold), the test is ended, and the actual failure cycle number and cycle length of the battery are summarized as the final aging test result. Based on the target acceleration factor calculated by the model, the multi-stress coupling loading is guided, so that the aging mechanism of the battery in the complex use scenario can be realistically reproduced in a limited experimental period, and the aging data highly consistent with the actual environmental degradation law can be obtained, which provides an efficient and accurate basis for subsequent battery design optimization and life prediction. As shown in the following table, the measured data table of battery life prediction accuracy is as follows: Preferably, the step of performing accelerated aging test on the target battery according to the target stress loading parameters combined with the multi-stress acceleration factor model to obtain aging test results comprises the following steps: inputting the target stress loading parameters into the multi-stress acceleration factor model to obtain a target acceleration factor; Specifically, the target stress loading parameters refer to the temperature determined after the foregoing modification and screening process, and the multi-stress acceleration factor model is a mathematical expression containing a temperature index, a vibration index, a rate index, and interaction coefficients, which is used to map the three stress coupling effects into a single acceleration factor, i.e., the target acceleration factor. By combining the finally determined target stress parameters as the input of the model, the acceleration factor of the battery under the combination relative to the reference working condition is quickly calculated, which lays a foundation for subsequent conversion of the acceleration cycle number into equivalent real time. The temperature, vibration, and rate values in the target stress loading parameters are directly brought into the following model formula to obtain the target acceleration factor AF: The calculated target acceleration factor represents the scaling factor of the battery life under the multiple loads relative to the reference condition. The complex three-factor coupling effect is quickly quantified into a single value that can be used for life conversion through the existing model, which avoids large-scale experiments again. An accurate acceleration rate can be obtained through one calculation, which provides a reliable basis for subsequent test time conversion.

[0057] According to the target stress loading parameters, the target battery is tested to obtain a single cycle time and a target cycle number, wherein the single cycle time includes the time required for the target battery to complete one complete charge and discharge cycle, and the target cycle number includes the number of charge and discharge cycles performed by the target battery when reaching a target aging state; Specifically, the single cycle time refers to the total time length required for the battery to complete one cycle from full charge to discharge to the cut-off voltage and recharge back to full (including the constant current and constant voltage stages); the target cycle number refers to the total number of charge-discharge reciprocating cycles experienced by the battery until it reaches the preset aging termination standard (such as capacity decay to 80% or internal resistance growth rate exceeding the threshold) under the action of the target stress loading parameter. According to the target stress loading parameter, a complete aging test is carried out under a real multi-stress environment, and the time consumed for each cycle and the cumulative cycle number at the time of final failure are accurately recorded during the test, so as to combine the cycle number data with the acceleration factor for equivalent time calculation. After the test is started, the time interval for each completed cycle is automatically measured and recorded (which can be obtained through a test instrument timestamp function or an external timer), until the Nth cycle reaches the capacity or internal resistance failure judgment, and the test is stopped; this N is the target cycle number, and the time length corresponding to each cycle constitutes a single cycle time curve. The cycle time and the failure cycle number are synchronously collected, which can accurately reflect the time variation trend of each cycle of the battery under the target loading condition, provide necessary basic data for subsequent rapid conversion of the cycle number into accelerated equivalent time, and can be used to observe the dynamic changes of the cycle efficiency with the decay stage.

[0058] According to the target acceleration factor, the single cycle time and the target cycle number are combined to calculate the aging equivalent test time.

[0059] Specifically, according to the calculated target acceleration factor, the single cycle time and the target cycle number are combined to calculate the aging equivalent test time by the following formula: Wherein, is the single cycle time, AF is the acceleration factor, is the target cycle number; the aging equivalent test time refers to the cumulative actual time required for the target battery to complete all failure cycles under the accelerated working condition, which is converted into the time required under the real working condition. Since the target acceleration factor has comprehensively considered the coupling effects of temperature, vibration and rate, and the cycle time accurately reflects the charge-discharge efficiency under different rates, the equivalent time of the actual accelerated test working condition and the real use condition is accurately related through a simple formula, so that the life estimation of the battery under the actual working condition can be obtained without long-term real aging test, which greatly saves the test time and cost under the real environment. The following table shows the measured data of the aging test time: Example 2 Please refer to Figure 2 , in combination Figure 1 The multi-stress battery accelerated aging test method of the embodiments of the application described in the specification can be realized by a multi-stress battery accelerated aging test system.Figure 2 A hardware structure diagram of a multi-stress battery accelerated aging test system is shown.

[0060] The multi-stress battery accelerated aging test system can include a processor and a memory storing computer program instructions.

[0061] Specifically, the processor can include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement one or more embodiments of the present application.

[0062] The memory can include non-persistent memory in computer readable media, random access memory (RAM), and / or non-volatile memory such as read only memory (ROM) or flash memory (flash RAM). The memory is an example of computer readable media.

[0063] Computer readable media includes permanent and non-permanent, removable and non-removable media, and can be implemented by any method or technology for information storage. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic disk storage or other magnetic storage device, or any other non-transmission medium that can be used to store information accessible by a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carriers.

[0064] The processor reads and executes the computer program instructions stored in the memory to implement any one of the multi-stress battery accelerated aging test methods in the above embodiments.

[0065] In one example, the multi-stress battery accelerated aging test system can further include a communication interface and a bus. As shown in Figure 2 The processor 401, the memory 402 and the communication interface 403 are connected by the bus 410 and complete communication with each other.

[0066] The communication interface is mainly used to realize the communication between the modules, devices, units and / or equipment in the embodiments of the present application.

[0067] The bus includes a hardware, software, or both that couples components of the multi-stress battery accelerated aging test system to each other. By way of example, and not limitation, the bus can include an accelerated graphics port (AGP) or other graphics bus, a peripheral component interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a serial advanced technology attachment (SATA) bus, a video electronics standards association local (VLB) bus, or another suitable bus or combination of two or more of these buses. Where appropriate, the bus can include one or more buses. Although the present embodiments describe and show a particular bus, the present embodiments contemplate any suitable bus or interconnect.

[0068] In summary, the present embodiments provide a multi-stress battery accelerated aging test method and system.

[0069] It should be understood that the present embodiments are not limited to the particular configurations, arrangements and processes described herein and illustrated in the drawings. Detailed descriptions of known methods are omitted so as not to obscure the description of the present embodiments. In the above-described embodiments, a number of specific steps are described and illustrated as examples. However, the methods process of the present embodiments are not limited to the specific steps described and illustrated, and one of ordinary skill in the art can make various changes, modifications and additions, or change the order of the steps, after understanding the spirit of the present embodiments.

[0070] Those skilled in the art will appreciate that embodiments of the present embodiments can be readily used for the purposes of the methods, systems and computer program products described herein. Accordingly, embodiments of the present embodiments can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present embodiments can take the form of a computer program product on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) embodying computer program instructions. The one or more computer-usable storage media have computer readable program code embodied therein and the computer readable program code is executed by one or more computer processors to implement the present embodiments.

[0071] The present embodiments are described with reference to the flowchart illustrations and / or block diagrams of the methods, apparatus (systems) and computer program products according to embodiments of the present embodiments. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing machine, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions of the flowchart and / or block diagrams of the methods, apparatus (systems) and computer program products according to embodiments of the present embodiments. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operations to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus implement the functions of the flowchart and / or block diagrams of the methods, apparatus (systems) and computer program products according to embodiments of the present embodiments. Figure 1one or more processes and / or blocks Figure 1 an apparatus for performing the functions specified in the flowchart or multiple flows and / or blocks.

[0072] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flowchart or multiple flows and / or blocks. Figure 1 one or more processes and / or blocks Figure 1 an apparatus for performing the functions specified in the flowchart or multiple flows and / or blocks.

[0073] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flowchart or multiple flows and / or blocks. Figure 1 one or more processes and / or blocks Figure 1 an apparatus for performing the functions specified in the flowchart or multiple flows and / or blocks.

[0074] It should also be noted that the exemplary embodiments mentioned in the present application describe some methods or systems based on a series of steps or apparatuses. However, the present application is not limited to the order of the above steps, that is, the steps can be executed in the order mentioned in the embodiments, or in an order different from the embodiments, or several steps can be executed simultaneously.

[0075] The above only describes specific implementation manners of the present application. It can be clearly understood by those skilled in the art that, for the convenience and brevity of description, the specific working process of the above-described system, module and unit can refer to the corresponding process in the foregoing method embodiments, which will not be described here. It should be understood that the protection scope of the present application is not limited to this. Any modifications or replacements obvious to those skilled in the art within the technical range disclosed by the present application should be covered by the protection scope of the present application.

Claims

1. A multi-stress battery accelerated aging test method, characterized in that: The method comprises: Obtaining a target combination parameter set according to a plurality of preset stress loading parameters for battery aging testing; According to the target combination parameter set, each stress loading parameter is calibrated to obtain each stress acceleration index; According to the preset reference stress loading parameters, combined with each target combination parameter and each stress acceleration index, a multi-stress acceleration factor model is established; Testing the target battery to be tested according to the preset original stress loading parameters, and correcting the original stress loading parameters according to the test results to obtain target stress loading parameters; According to the target stress loading parameters and in combination with the multi-stress acceleration factor model, an accelerated aging test is performed on the target battery to obtain an aging test result.

2. The multi-stress battery accelerated aging test method according to claim 1, characterized in that: The stress loading parameters are calibrated according to the target combination parameters to obtain the stress acceleration index, including: Obtaining preset material constants, reference vibration life constants, and reference charge-discharge rate life constants; Testing the target battery according to the target combination parameter set to obtain a cycle life set of the target battery; The stress acceleration index is calculated based on the cycle life set in combination with the material constant, the reference vibration life constant and the reference charge and discharge rate life constant.

3. The multi-stress battery accelerated aging test method according to claim 2, characterized in that: The target combination parameter set includes a first combination parameter set, a second combination parameter set, and a third combination parameter set; the first combination parameter, the second combination parameter, and the third combination parameter all include vibration acceleration values, charge and discharge rates, and temperature values; The first combination parameters in the first combination parameter set have the same vibration acceleration value, the same charge and discharge rate, and different temperature values; the second combination parameters in the second combination parameter set have different vibration acceleration values, the same charge and discharge rate, and the same temperature value; the third combination parameters in the third combination parameter set have the same vibration acceleration value, different charge and discharge rates, and the same temperature value.

4. The multi-stress battery accelerated aging test method according to claim 1, characterized in that: The step of testing the target battery according to the target combination parameter set to obtain a cycle life set of the target battery includes: Testing the target battery according to the target combination parameter set; Acquire the battery capacity value and the first internal resistance value during the battery test according to a preset data acquisition frequency; Determining whether a test termination condition is met based on the battery capacity value and the first internal resistance value, in combination with a preset capacity decay threshold and a first internal resistance growth rate threshold; When it is determined that the test termination condition is met, the cycle life set is determined according to the number of charge and discharge cycles of the battery during the test.

5. The multi-stress battery accelerated aging test method according to claim 3, characterized in that: The cycle life set includes a first cycle life corresponding to each of the first combination parameters, a second cycle life corresponding to each of the second combination parameters, and a third cycle life corresponding to each of the third combination parameters; the stress acceleration index calculated based on the cycle life, combined with the material constant, the reference vibration life constant, and the reference charge and discharge rate life constant, includes: Calculating a temperature acceleration index based on each of the first cycle life and the material constant in combination with each temperature value in the first combination parameter set; Calculating a vibration acceleration index based on each of the second cycle life and the reference vibration life constant in combination with each vibration acceleration value in the second combination parameter set; Calculating a charge and discharge rate acceleration index based on each of the third cycle life and the reference charge and discharge rate life constant in combination with each charge and discharge rate in the third combination parameter set; The stress acceleration indexes are determined according to the temperature acceleration index, the vibration acceleration index and the charge-discharge rate acceleration index.

6. The multi-stress battery accelerated aging test method according to claim 2, characterized in that: The establishing of a multi-stress acceleration factor model based on the preset baseline stress loading parameters, in combination with each target combination parameter and each stress acceleration index, includes: Obtaining a reference temperature value and a reference vibration acceleration value according to the reference stress loading parameter; Testing the target battery according to the reference temperature value and the reference vibration acceleration value to obtain a reference cycle life; Calculating the reference cycle life and the cycle life set using a least squares method to obtain an interaction coefficient; The multi-stress acceleration factor model is established based on the interaction coefficient, the baseline stress loading parameter and each stress acceleration index, combined with each target combination parameter.

7. The multi-stress battery accelerated aging test method according to claim 4, characterized in that: The target battery to be tested is tested according to the preset original stress loading parameters, and the original stress loading parameters are corrected according to the test results to obtain the target stress loading parameters, which include: Obtaining the original stress loading parameters that meet the battery safety test requirements according to a preset stress loading parameter safety threshold; Testing the target battery according to the original stress loading parameters; Acquiring multiple second internal resistance values ​​of the target battery during the test according to the data acquisition frequency; calculating, based on adjacent internal resistance values ​​among the second internal resistance values, an internal resistance growth rate corresponding to each adjacent internal resistance value; When a target internal resistance growth rate appears in each of the internal resistance growth rates and is greater than a preset second internal resistance growth rate threshold, the original stress loading parameter is corrected according to the adjacent internal resistance value corresponding to the target internal resistance growth rate to obtain the target stress loading parameter.

8. The multi-stress battery accelerated aging test method according to claim 7, characterized in that: When a target internal resistance growth rate appears in each of the internal resistance growth rates and is greater than a preset second internal resistance growth rate threshold, the original stress loading parameter is corrected according to the adjacent internal resistance value corresponding to the target internal resistance growth rate to obtain the target stress loading parameter, which includes: Calculate the open circuit voltage change rate within a single battery charge and discharge cycle based on the charge and discharge voltage and current collected at a preset data collection frequency during the test to obtain a target open circuit voltage change rate; The integrated value of the charge and discharge capacity collected at the preset data collection frequency during the test is compared with the charge capacity and discharge capacity to obtain the target coulombic efficiency of the current charge and discharge cycle; Based on the charge and discharge voltage and capacity data during the test, differential capacity analysis is performed to obtain the target differential capacity characteristic change corresponding to the current cycle; Comparing the target open circuit voltage change rate, target coulombic efficiency, and target differential capacity characteristic change amount with preset open circuit voltage change rate thresholds, coulombic efficiency thresholds, and target differential capacity characteristic change amount thresholds to determine whether there are abnormal degradation indicators exceeding the thresholds; When the target open circuit voltage change rate is greater than the open circuit voltage change rate threshold, and / or the target coulombic efficiency is greater than the coulombic efficiency threshold, and / or the target differential capacity characteristic change is greater than the target differential capacity characteristic change threshold, calculating a target internal resistance growth rate based on adjacent internal resistance values ​​at the current moment, and determining whether the target internal resistance growth rate exceeds the second internal resistance growth rate threshold; When the target internal resistance growth rate is greater than the second internal resistance growth rate threshold, the original stress loading parameter is corrected according to adjacent internal resistance values ​​corresponding to the target internal resistance growth rate to obtain the target stress loading parameter.

9. The multi-stress battery accelerated aging test method according to any one of claims 1 to 8, characterized in that: After performing an accelerated aging test on the target battery according to the target stress loading parameter and in combination with the multi-stress acceleration factor model to obtain an aging test result, the method further includes: Inputting the target stress loading parameter into the multi-stress acceleration factor model to obtain a target acceleration factor; Testing the target battery according to the target stress loading parameters to obtain a single cycle time and a target number of cycles, wherein the single cycle time includes the time required for the target battery to complete a full charge and discharge cycle, and the target number of cycles includes the number of charge and discharge cycles performed when the target battery reaches a target aging state; The aging equivalent test time is calculated according to the target acceleration factor, combined with the single cycle time and the target number of cycles.

10. A multi-stress battery accelerated aging test system, characterized in that: include: At least one processor, at least one memory, and computer program instructions stored in the memory, which implement the method according to any one of claims 1 to 9 when the computer program instructions are executed by the processor.

Images