Method and device for detecting battery capacity attenuation inflection point

Abstract

The invention relates to the technical field of battery management, in particular to a battery capacity attenuation inflection point detection method and device, and the method comprises the steps: collecting the actual charging data of a to-be-detected battery in the charging process under the condition that the to-be-detected battery is charged at least twice to a target micro-overcharge cut-off voltage value; calculating an actual difference increment capacity value of the to-be-detected battery based on the actual charging data, calculating an actual normalized peak change rate of the to-be-detected battery, and detecting whether the actual normalized peak change rate is smaller than a preset battery capacity attenuation inflection point threshold; and if yes, determining that the to-be-detected battery enters a battery capacity fading diving stage. Therefore, the problems of long test period, high cost, lack of a systematic solution integrating an electrochemical mechanism and data characteristics, difficulty in meeting the current requirements on accurate evaluation and efficient analysis of the battery performance and the like caused by dependence on a large amount of experimental data support or through a complex model parameter calibration process in the related technology are solved.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to a method and apparatus for detecting the inflection point of battery capacity decay. Background Technology

[0002] In related technologies, the total reaction current density and negative electrode deposition parameters of the lithium-ion battery at different time steps in each simulated cycle can be obtained first. Then, based on the total reaction current density and negative electrode deposition parameters, the battery capacity and cumulative total number of cycles corresponding to each simulated cycle can be calculated. When the battery capacity or the total number of cycles reaches a preset threshold, a capacity decay curve is generated. Alternatively, the battery capacity can be normalized first, and the current remaining usable capacity of the battery can be represented by the battery health state to obtain the battery capacity decay curve. The start and end points of the battery capacity decay curve can be connected to obtain the linear aging curve of the battery. Thus, the inflection point of the battery capacity decay curve can be determined based on the aging nonlinearity in the battery capacity decay curve.

[0003] However, related technologies often rely on massive amounts of experimental data or complex model parameter calibration processes, which not only lead to lengthy testing cycles and high costs, but also lack a systematic solution that can deeply integrate electrochemical mechanisms and data characteristics. This makes it difficult to meet the current demand for accurate evaluation and efficient analysis of battery performance and urgently needs improvement. Summary of the Invention

[0004] This application provides a method and apparatus for detecting the inflection point of battery capacity decay, in order to solve the technical problems in related technologies, which often rely on a large amount of experimental data or a complex model parameter calibration process, resulting in long testing cycles, high costs, and a lack of systematic solutions that integrate electrochemical mechanisms and data characteristics, making it difficult to meet the current demand for accurate evaluation and efficient analysis of battery performance.

[0005] The first aspect of this application provides a method for detecting the inflection point of battery capacity decay, comprising the following steps: collecting actual charging data of the battery under test during the charging process after charging the battery to a target micro-overcharge cutoff voltage value at least twice; calculating the actual differential incremental capacity value of the battery under test based on the actual charging data, and calculating the actual normalized peak value change rate of the battery under test based on the actual differential incremental capacity value, and detecting whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold; if the actual normalized peak value change rate is detected to be less than the preset battery capacity decay inflection point threshold, determining that the battery under test has entered the battery capacity decay plunge stage.

[0006] The above technical solution allows for the collection of actual charging data during the charging process of the battery under test, after charging it to the target micro-overcharge cutoff voltage value at least twice. Based on this data, the actual differential incremental capacity value of the battery under test is calculated, and then the actual normalized peak value change rate is calculated. The solution also checks whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold. If it is less, the battery is determined to have entered the battery capacity decay plunge stage. This method reduces the influence of interference factors, improves detection accuracy, is simple to calculate, has high sensitivity, improves detection efficiency, reduces detection costs, and is suitable for battery management systems to manage capacity, thereby enhancing battery safety.

[0007] Optionally, in one embodiment of this application, before detecting whether the actual normalized peak change rate is less than a preset battery capacity decay inflection point threshold, the method further includes: collecting charging data of the target battery under test during the charging process, provided that the target battery under test has been charged to the target micro-overcharge cutoff voltage value at least twice; calculating the differential incremental capacity value of the target battery under test based on the charging data, and calculating the normalized peak change rate of the target battery under test based on the differential incremental capacity value; and determining the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate.

[0008] The above technical solution allows for the collection of charging data before detecting whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold. This is achieved by charging the target battery to the target micro-overcharge cutoff voltage value at least twice. The differential incremental capacity value is then calculated, and the normalized peak change rate is calculated based on this value to determine the corresponding battery capacity decay inflection point threshold. By collecting the charging data of the target battery itself, the threshold is determined to better reflect its actual capacity decay, thus improving the accuracy of subsequent testing. This method is applicable to various battery types, enhancing testing adaptability, and eliminates the need for large-scale preliminary research, saving time and costs and improving testing efficiency.

[0009] Optionally, in one embodiment of this application, determining the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate includes: determining an initial threshold for the battery capacity decay inflection point of the target battery under test based on the normalized peak change rate; determining whether the target battery under test has entered the battery capacity decay plunge stage based on the initial threshold; if the target battery under test has entered the battery capacity decay plunge stage, determining the battery capacity decay inflection point threshold based on the initial threshold; if the target battery under test has not entered the battery capacity decay plunge stage, recharging the target battery under test to the target micro-overcharge cutoff voltage value until the target battery under test enters the battery capacity decay plunge stage to obtain a new initial threshold, and determining the battery capacity decay inflection point threshold based on the new initial threshold.

[0010] The above technical solution can determine the initial threshold of the battery capacity decay inflection point of the target battery based on the normalized peak change rate, and determine whether the target battery has entered the battery capacity decay plunge stage. If it has, the battery capacity decay inflection point threshold is determined according to the initial threshold. Otherwise, the target battery is recharged to the target micro-overcharge cutoff voltage value until the target battery enters the battery capacity decay plunge stage, so that the battery capacity decay inflection point threshold can be determined according to the new initial threshold. This can more accurately capture the unique capacity decay inflection point characteristics of different batteries, making the determined threshold more consistent with the actual battery decay situation, avoiding the inaccuracy of the threshold caused by the use of a uniform standard. Through multiple charging and judgment, the interference of random factors is reduced, the reliability of the threshold is improved, and it can adapt to different types and states of batteries, enhancing the adaptability and flexibility of the detection.

[0011] Optionally, in one embodiment of this application, the step of calculating the actual differential incremental capacity value of the battery under test based on the actual charging data includes: obtaining the current voltage value and current charge value of the battery under test at at least two moments based on the actual charging data; calculating the actual incremental capacity value of the battery under test based on the current voltage value and the current charge value; and calculating the actual differential incremental capacity value based on the actual incremental capacity value.

[0012] The above technical solution allows for the acquisition of the current voltage and charge values ​​of the battery under test at at least two moments based on actual charging data. This enables the calculation of the actual incremental capacity value of the battery under test, thereby obtaining the actual differential incremental capacity value. This approach can meticulously capture the state of the battery at different points in time during charging, thus providing a more accurate description of the battery's capacity changes within a specific voltage range. It avoids errors caused by insufficient or coarse data sampling. Through hierarchical calculations, a deeper understanding of the battery's capacity decay characteristics and internal electrochemical processes can be achieved, providing a more accurate basis for subsequent detection of the battery capacity decay inflection point and improving the sensitivity of capacity decay inflection point detection.

[0013] Optionally, in one embodiment of this application, the step of calculating the actual normalized peak change rate of the battery under test based on the actual differential incremental capacity value includes: extracting a target peak value from the actual differential incremental capacity value; determining a normalization threshold for the battery under test based on the target peak value; normalizing the actual differential incremental capacity value based on the normalization threshold to obtain a normalized peak height; and calculating the actual normalized peak change rate based on the normalized peak height.

[0014] The above technical solution can first extract the target peak value from the actual differential incremental capacity value, thereby determining the normalization threshold of the battery under test, and then normalizing it to obtain the normalized peak height. Then, the actual normalized peak change rate can be calculated, adapting to different battery characteristics, eliminating the influence of individual differences, enhancing the accuracy of feature extraction, reflecting the battery status more accurately, improving detection sensitivity and accuracy, and providing stronger support for battery management and maintenance.

[0015] A second aspect of this application provides a device for detecting the inflection point of battery capacity decay, comprising: a first acquisition module, configured to acquire actual charging data of the battery under test during the charging process after the battery under test has been charged to a target micro-overcharge cutoff voltage value at least twice; a detection module, configured to calculate the actual differential incremental capacity value of the battery under test based on the actual charging data, and calculate the actual normalized peak value change rate of the battery under test based on the actual differential incremental capacity value, and detect whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold; and a determination module, configured to determine that the battery under test has entered the battery capacity decay plunge stage when the actual normalized peak value change rate is detected to be less than the preset battery capacity decay inflection point threshold.

[0016] The above technical solution allows for the collection of actual charging data during the charging process of the battery under test, after charging it to the target micro-overcharge cutoff voltage value at least twice. Based on this data, the actual differential incremental capacity value of the battery under test is calculated, and then the actual normalized peak value change rate is calculated. The solution also checks whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold. If it is less, the battery is determined to have entered the battery capacity decay plunge stage. This method reduces the influence of interference factors, improves detection accuracy, is simple to calculate, has high sensitivity, improves detection efficiency, reduces detection costs, and is suitable for battery management systems to manage capacity, thereby enhancing battery safety.

[0017] Optionally, in one embodiment of this application, it further includes: a second acquisition module, configured to acquire charging data of the target battery under test during the charging process, provided that the target battery under test has been charged to the target micro-overcharge cutoff voltage value at least twice, before detecting whether the actual normalized peak change rate is less than a preset battery capacity decay inflection point threshold; a calculation module, configured to calculate the differential incremental capacity value of the target battery under test based on the charging data, and calculate the normalized peak change rate of the target battery under test based on the differential incremental capacity value; and a determination module, configured to determine the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate.

[0018] The above technical solution allows for the collection of charging data before detecting whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold. This is achieved by charging the target battery to the target micro-overcharge cutoff voltage value at least twice. The differential incremental capacity value is then calculated, and the normalized peak change rate is calculated based on this value to determine the corresponding battery capacity decay inflection point threshold. By collecting the charging data of the target battery itself, the threshold is determined to better reflect its actual capacity decay, thus improving the accuracy of subsequent testing. This method is applicable to various battery types, enhancing testing adaptability, and eliminates the need for large-scale preliminary research, saving time and costs and improving testing efficiency.

[0019] Optionally, in one embodiment of this application, the determining module includes: a first determining unit, configured to determine an initial threshold for the battery capacity decay inflection point of the target battery under test based on the normalized peak change rate; a judging unit, configured to judge whether the target battery under test has entered the battery capacity decay plunge stage based on the initial threshold; a second determining unit, configured to determine the battery capacity decay inflection point threshold according to the initial threshold when the target battery under test enters the battery capacity decay plunge stage; and a third determining unit, configured to recharge the target battery under test to the target micro-overcharge cutoff voltage value until the target battery under test enters the battery capacity decay plunge stage when the target battery under test has not entered the battery capacity decay plunge stage, so as to obtain a new initial threshold, and determine the battery capacity decay inflection point threshold according to the new initial threshold.

[0020] The above technical solution can determine the initial threshold of the battery capacity decay inflection point of the target battery based on the normalized peak change rate, and determine whether the target battery has entered the battery capacity decay plunge stage. If it has, the battery capacity decay inflection point threshold is determined according to the initial threshold. Otherwise, the target battery is recharged to the target micro-overcharge cutoff voltage value until the target battery enters the battery capacity decay plunge stage, so that the battery capacity decay inflection point threshold can be determined according to the new initial threshold. This can more accurately capture the unique capacity decay inflection point characteristics of different batteries, making the determined threshold more consistent with the actual battery decay situation, avoiding the inaccuracy of the threshold caused by the use of a uniform standard. Through multiple charging and judgment, the interference of random factors is reduced, the reliability of the threshold is improved, and it can adapt to different types and states of batteries, enhancing the adaptability and flexibility of the detection.

[0021] Optionally, in one embodiment of this application, the detection module includes: an acquisition unit, configured to acquire the current voltage value and current charge value of the battery under test at at least two moments based on the actual charging data; a first calculation unit, configured to calculate the actual incremental capacity value of the battery under test based on the current voltage value and the current charge value; and a second calculation unit, configured to calculate the actual differential incremental capacity value based on the actual incremental capacity value.

[0022] The above technical solution allows for the acquisition of the current voltage and charge values ​​of the battery under test at at least two moments based on actual charging data. This enables the calculation of the actual incremental capacity value of the battery under test, thereby obtaining the actual differential incremental capacity value. This approach can meticulously capture the state of the battery at different points in time during charging, thus providing a more accurate description of the battery's capacity changes within a specific voltage range. It avoids errors caused by insufficient or coarse data sampling. Through hierarchical calculations, a deeper understanding of the battery's capacity decay characteristics and internal electrochemical processes can be achieved, providing a more accurate basis for subsequent detection of the battery capacity decay inflection point and improving the sensitivity of capacity decay inflection point detection.

[0023] Optionally, in one embodiment of this application, the detection module includes: an extraction unit for extracting a target peak value from the actual differential incremental capacity value; a fourth determination unit for determining a normalization threshold for the battery under test based on the target peak value; a normalization unit for normalizing the actual differential incremental capacity value based on the normalization threshold to obtain a normalized peak height; and a third calculation unit for calculating the actual normalized peak change rate based on the normalized peak height.

[0024] The above technical solution can first extract the target peak value from the actual differential incremental capacity value, thereby determining the normalization threshold of the battery under test, and then normalizing it to obtain the normalized peak height. Then, the actual normalized peak change rate can be calculated, adapting to different battery characteristics, eliminating the influence of individual differences, enhancing the accuracy of feature extraction, reflecting the battery status more accurately, improving detection sensitivity and accuracy, and providing stronger support for battery management and maintenance.

[0025] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the battery capacity decay inflection point detection method as described in the above embodiments.

[0026] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for detecting the inflection point of battery capacity decay.

[0027] A fifth aspect of this application provides a computer program product, including a computer program that, when executed, implements the above-described method for detecting the inflection point of battery capacity decay.

[0028] This application embodiment can collect actual charging data of the battery under test during the charging process after charging the battery to the target micro-overcharge cutoff voltage value at least twice. Based on the actual charging data, it calculates the actual differential incremental capacity value of the battery under test, and then calculates the actual normalized peak value change rate of the battery under test. It detects whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold. If it is less, it determines that the battery has entered the battery capacity decay plunge stage. By determining whether the battery has entered the battery capacity decay plunge stage based on the pre-predicted battery capacity decay inflection point threshold, it reduces the influence of interference factors, improves the accuracy of detection, and features simple calculation, high sensitivity, improved detection efficiency, and reduced detection costs. It is suitable for battery management systems to manage capacity and enhance battery safety. Therefore, it solves the technical problems in related technologies, which often rely on a large amount of experimental data or complex model parameter calibration processes, resulting in long testing cycles, high costs, and a lack of systematic solutions integrating electrochemical mechanisms and data characteristics, making it difficult to meet the current needs for accurate battery performance evaluation and efficient analysis.

[0029] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0030] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a method for detecting the inflection point of battery capacity decay according to an embodiment of this application; Figure 2 This is a schematic diagram illustrating the principle of identifying the inflection point of the micro-overcharge differential incremental capacity curve according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating the variation of sample cycling capacity and micro-overcharge normalized peak change rate with cycling period according to an embodiment of this application; Figure 4 This is a flowchart illustrating the working principle of a battery capacity decay inflection point detection method according to an embodiment of this application; Figure 5 This is a block diagram of a battery capacity decay inflection point detection device provided according to an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application.

[0031] Figure label: Among them, 10-a detection device for the inflection point of battery capacity decay; 100-first acquisition module, 200-detection module, 300-judgment module; 601-memory, 602-processor, 603-communication interface. Detailed Implementation

[0032] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0033] The following describes a method and apparatus for detecting the inflection point of battery capacity decay according to embodiments of this application, with reference to the accompanying drawings. Addressing the issues mentioned in the background art, which often rely on extensive experimental data or complex model parameter calibration processes, resulting in long testing cycles, high costs, and a lack of systematic solutions integrating electrochemical mechanisms and data characteristics, making it difficult to meet the current needs for accurate battery performance evaluation and efficient analysis, this application provides a method for detecting the inflection point of battery capacity decay. In this method, the actual charging data of the battery under test is collected during the charging process after at least two charging cycles to the target micro-overcharge cutoff voltage value. The actual differential incremental capacity value of the battery under test is calculated based on the actual charging data, and then the actual normalized peak value change rate of the battery under test is calculated. The method then detects whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold. If it is less, it is determined that the battery has entered the battery capacity decay plunge stage. By determining whether the battery has entered the battery capacity decay plunge stage based on the pre-predicted battery capacity decay inflection point threshold, the influence of interference factors is reduced, the detection accuracy is improved, the calculation is simple, the sensitivity is high, the detection efficiency is improved, and the detection cost is reduced. This method is suitable for battery management systems to manage capacity and enhance battery safety. This solves the technical problems in related technologies, such as the need to rely on a large amount of experimental data or a complex model parameter calibration process, which leads to long testing cycles, high costs, and a lack of systematic solutions that integrate electrochemical mechanisms and data characteristics, making it difficult to meet the current demand for accurate evaluation and efficient analysis of battery performance.

[0034] Specifically, Figure 1 This is a flowchart of a method for detecting the inflection point of battery capacity decay according to an embodiment of this application.

[0035] like Figure 1 As shown, the method for detecting the inflection point of battery capacity degradation includes the following steps: In step S101, the actual charging data of the battery under test during the charging process is collected after the battery under test has been charged to the target micro-overcharge cutoff voltage value at least twice.

[0036] It is understood that the embodiments of this application can amplify the battery aging characteristic signal by adding two micro-overcharge cycles. Here, micro-overcharge refers to a charging voltage slightly higher than the normal value by 0.1~0.3V, and its expression can be, but is not limited to, as follows: (1) in, Indicates the micro-overcharge cutoff voltage. This indicates the normal charging cutoff voltage. This represents a given voltage difference, which can range from 0.1 to 0.3V.

[0037] In some embodiments of this application, when testing the battery under test, the battery under test can be charged at least twice to make the charging voltage of the battery under test reach the target micro-overcharge cutoff voltage value, and the actual charging data generated by the battery under test during the charging process can be collected.

[0038] Optionally, in one embodiment of this application, before detecting whether the actual normalized peak change rate is less than a preset battery capacity decay inflection point threshold, the method further includes: collecting charging data of the target battery during the charging process after the target battery under test has been charged to the target micro-overcharge cutoff voltage value at least twice; calculating the differential incremental capacity value of the target battery under test based on the charging data, and calculating the normalized peak change rate of the target battery under test based on the differential incremental capacity value; and determining the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate.

[0039] As one possible implementation, in this embodiment of the application, before detecting whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold, at least two charging operations can be performed on the target battery under test to ensure that the target battery under test reaches the target micro-overcharge cutoff voltage value in each charging operation. Charging data of the target battery under test during the charging process is collected, and then the differential incremental capacity value of the target battery under test is calculated based on the collected charging data. Using the differential incremental capacity value as the basis for calculation, the normalized peak change rate of the target battery under test is further calculated. Thus, the battery capacity decay inflection point threshold corresponding to the target battery under test is determined based on the calculated normalized peak change rate.

[0040] For example, in the embodiments of this application, a normal cycle step of the target battery under test can be set, and periodic micro-overcharge cycles can be injected. The periodicity can be understood as adding two micro-overcharge cycles every several normal cycles, thereby obtaining the charging data of the target battery under test during the charging process.

[0041] Furthermore, embodiments of this application can calculate incremental capacity values ​​based on charging data to construct incremental capacity curves. The formula for calculating incremental capacity values ​​is shown in equation (2), and its expression can be, but is not limited to, as follows: (2) in, express Current battery level at any given moment. express Current battery level at any given moment. express The current voltage value at that moment. express The current voltage value at that moment. This represents the incremental capacity value.

[0042] Furthermore, in this embodiment, the incremental capacity curve is Gaussian smoothed and central difference processed to obtain differential incremental capacity values, thereby constructing a differential incremental capacity curve. The calculation formula for the differential incremental capacity value is shown in equation (3), and its expression can be, but is not limited to, as follows: , in, This represents the differential increment capacity value, used to enhance the identifiability of features before the inflection point.

[0043] Furthermore, in this embodiment of the application, the normalized peak change rate of the target battery under test can be calculated based on the differential incremental capacity value, thereby determining the battery capacity decay inflection point threshold of the target battery under test.

[0044] For example, in this embodiment of the application, a 25Ah nickel-cobalt-manganese pouch battery can be cycled at 25°C and 1C, with two 4.4V micro-overcharge cycles every 48 weeks. After collecting voltage-capacity charging data, Gaussian smoothing is performed first, followed by a second center differential calculation to obtain a differential incremental capacity curve, such as... Figure 2 As shown, the target peak value of the curve in each cycle can be clearly seen.

[0045] Furthermore, in this embodiment, the target peak value (battery voltage range of 3.6V-3.7V) can be extracted as a feature parameter, and the voltage peak value of each cycle can be compared with the initial voltage peak value for normalization, and the normalized peak value change rate can be calculated. Compare the NPVR with the capacity change value for different cycle periods, such as Figure 3 As shown, The changes occurred significantly earlier than the inflection point threshold of the battery capacity decay of the target battery under test.

[0046] Optionally, in one embodiment of this application, determining the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate includes: determining an initial threshold for the battery capacity decay inflection point of the target battery under test based on the normalized peak change rate; determining whether the target battery under test has entered the battery capacity decay plunging stage based on the initial threshold; if the target battery under test has entered the battery capacity decay plunging stage, determining the battery capacity decay inflection point threshold based on the initial threshold; if the target battery under test has not entered the battery capacity decay plunging stage, recharging the target battery under test to the target micro-overcharge cutoff voltage value until the target battery under test enters the battery capacity decay plunging stage to obtain a new initial threshold, and determining the battery capacity decay inflection point threshold based on the new initial threshold.

[0047] In some embodiments, the present application embodiments may first determine the initial threshold of the battery capacity decay inflection point of the target battery under test based on the normalized peak change rate, and then determine whether the target battery under test has entered the battery capacity decay plunge stage based on the initial threshold. If it has entered the battery capacity decay plunge stage, the initial threshold is used as the battery capacity decay inflection point threshold of the target battery under test. If it has not entered the battery capacity decay plunge stage, the target battery under test is recharged to the target micro-overcharge cutoff voltage value, and a new normalized peak change rate is obtained again until the target battery under test enters the battery capacity decay plunge stage, thereby determining a new initial threshold to obtain the battery capacity decay inflection point threshold of the target battery under test.

[0048] For example, in this embodiment of the application, a normalized peak change rate during the cyclic process is first... The initial threshold is used as the inflection point for battery capacity degradation. That is, when the rate of change of other normalized peak values ​​is lower than the initial threshold, the target battery under test enters the stage of rapid battery capacity degradation. In this application embodiment, the database of battery capacity degradation and changes in the rate of change of normalized peak values ​​can be continuously accumulated to optimize the initial threshold of the inflection point for battery capacity degradation and improve the accuracy of determining whether the battery has entered the stage of rapid battery capacity degradation.

[0049] In some embodiments of this application, if the target battery under test has not entered the battery capacity degradation drop stage when other normalized peak change rates are lower than the initial threshold, the target battery under test is recharged to the target micro-overcharge cutoff voltage value, and a new normalized peak change rate is obtained again until the target battery under test enters the battery capacity degradation drop stage, thereby determining a new initial threshold to obtain the battery capacity degradation inflection point threshold of the target battery under test.

[0050] In some embodiments of this application, when the rate of change of other normalized peak values ​​is lower than the initial threshold, the target battery under test enters the stage of rapid battery capacity decay. At this time, the initial threshold can be used as the inflection point threshold of battery capacity decay of the target battery under test.

[0051] In step S102, the actual differential incremental capacity value of the battery under test is calculated based on the actual charging data, and the actual normalized peak change rate of the battery under test is calculated based on the actual differential incremental capacity value. It is then detected whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold.

[0052] In some embodiments, the present application can calculate the corresponding actual differential incremental capacity value based on the actual charging data of the battery under test, and then calculate the actual normalized peak change rate of the battery under test, thereby detecting whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold.

[0053] Optionally, in one embodiment of this application, calculating the actual differential incremental capacity value of the battery under test based on actual charging data includes: obtaining the current voltage value and current charge value of the battery under test at at least two moments based on actual charging data; calculating the actual incremental capacity value of the battery under test based on the current voltage value and current charge value; and calculating the actual differential incremental capacity value based on the actual incremental capacity value.

[0054] As one possible implementation method, embodiments of this application can obtain the current voltage and current charge values ​​of the battery under test at at least two moments based on actual charging data, and then calculate the actual incremental capacity value of the battery under test based on the current voltage and current charge values, thereby calculating the actual differential incremental capacity value based on the actual incremental capacity value.

[0055] For example, in this application embodiment, the current voltage value and current charge value of the battery under test at at least two moments can be obtained based on the actual charging data, and then the actual incremental capacity value of the battery under test can be calculated by combining formula (2), and the actual differential incremental capacity value of the battery under test can be calculated by formula (3).

[0056] Optionally, in one embodiment of this application, calculating the actual normalized peak change rate of the battery under test based on the actual differential incremental capacity value includes: extracting the target peak value from the actual differential incremental capacity value; determining the normalization threshold of the battery under test based on the target peak value; normalizing the actual differential incremental capacity value based on the normalization threshold to obtain the normalized peak height; and calculating the actual normalized peak change rate based on the normalized peak height.

[0057] In some embodiments, when calculating the actual normalized peak value change rate of the battery under test, this application can first extract the target peak value from the actual differential incremental capacity value, then determine the normalization threshold of the battery under test based on the target peak value, and normalize the actual differential incremental capacity value based on the normalization threshold to obtain the normalized peak height, thereby calculating the actual normalized peak value change rate. The target peak value can be the voltage peak value, and can be specifically set by those skilled in the art according to actual conditions; this application does not impose specific limitations.

[0058] For example, in this application embodiment, the voltage peak value in the actual differential incremental capacity value can be extracted and normalized to obtain the normalized peak height. The normalization process can be understood as dividing the target peak value of each cycle by the target peak value of the first micro-overcharge cycle.

[0059] Furthermore, in this embodiment of the application, the rate of change of the normalized peak height with the cycle is calculated to obtain the actual normalized peak change rate. The calculation formula is shown in (4), and its expression can be, but is not limited to, as follows: (4) in, Indicates the first The normalized peak height of Zhou; Indicates the first The normalized peak height of Zhou Indicates the period of slight overcharge; It represents the normalized peak change rate, which serves as the core indicator for inflection point prediction.

[0060] In step S103, if the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold, the battery under test is determined to have entered the battery capacity decay plunge stage.

[0061] In actual implementation, the embodiments of this application can determine that the battery under test has entered the battery capacity degradation stage when the actual normalized peak change rate is less than the preset battery capacity degradation inflection point threshold.

[0062] The working principle of the battery capacity decay inflection point detection method proposed in this application will be introduced below with reference to a specific embodiment.

[0063] in, Figure 4 This is a flowchart illustrating the working principle of a battery capacity decay inflection point detection method according to an embodiment of this application.

[0064] Step S401: The battery under test is subjected to micro-overcharge.

[0065] In this embodiment, a 25Ah nickel-cobalt-manganese pouch battery is cycled at 25°C and 1C, with two 4.4V micro-overcharge cycles every 48 weeks, and the actual voltage-capacity charging data is collected. The expression for micro-overcharge is shown in equation (1).

[0066] Step S402: Construct the incremental capacity curve.

[0067] In this application embodiment, an incremental capacity curve can be constructed based on actual charging data.

[0068] Step S403: Construct the differential incremental capacity curve.

[0069] In this application embodiment, a differential incremental capacity curve can be constructed based on the incremental capacity curve.

[0070] Step S404: Extract the target peak value.

[0071] In this application, the embodiments are combined with Figure 2 As shown, the target peak value of the curve in each cycle can be clearly seen.

[0072] Step S405: Determine the threshold value of the battery capacity decay inflection point for the battery under test.

[0073] In this embodiment, the target peak value of each cycle, such as the voltage peak value, can be compared with the initial voltage peak value, and then normalized to obtain... This allows us to determine the threshold for the inflection point of battery capacity degradation.

[0074] Step S406: Battery management system output.

[0075] In this embodiment, the comparison result between the actual normalized peak change rate and the preset battery capacity degradation inflection point threshold can be input into the battery management system in real time to achieve online monitoring, status assessment, and lifespan warning. For example, if the actual normalized peak change rate is less than the preset battery capacity degradation inflection point threshold, this embodiment can determine that the battery under test has entered the battery capacity degradation plunge stage and issue a warning.

[0076] The battery capacity decay inflection point detection method proposed in this application can collect actual charging data of the battery under test during the charging process after charging the battery to the target micro-overcharge cutoff voltage value at least twice. Based on the actual charging data, the actual differential incremental capacity value of the battery under test is calculated, and then the actual normalized peak value change rate of the battery under test is calculated. The method detects whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold. If it is less, it is determined that the battery has entered the battery capacity decay plunge stage. This method uses a pre-predicted battery capacity decay inflection point threshold to determine whether the battery has entered the battery capacity decay plunge stage, reducing the influence of interference factors, improving detection accuracy, simplifying calculations, increasing sensitivity, improving detection efficiency, and reducing detection costs. It is suitable for battery management systems to manage capacity and enhance battery safety. Therefore, it solves the technical problems in related technologies, which often rely on a large amount of experimental data or complex model parameter calibration processes, resulting in long testing cycles, high costs, and a lack of systematic solutions integrating electrochemical mechanisms and data characteristics, making it difficult to meet the current needs for accurate battery performance evaluation and efficient analysis.

[0077] Next, the device for detecting the inflection point of battery capacity decay according to an embodiment of this application is described with reference to the accompanying drawings.

[0078] Figure 5 This is a block diagram of a battery capacity decay inflection point detection device provided according to an embodiment of this application.

[0079] like Figure 5 As shown, the battery capacity decay inflection point detection device 10 includes: a first acquisition module 100, a detection module 200, and a determination module 300.

[0080] The first acquisition module 100 is used to acquire the actual charging data of the battery under test during the charging process, provided that the battery under test is charged to the target micro-overcharge cutoff voltage value at least twice.

[0081] The detection module 200 is used to calculate the actual differential incremental capacity value of the battery under test based on the actual charging data, and to calculate the actual normalized peak change rate of the battery under test based on the actual differential incremental capacity value, and to detect whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold.

[0082] The determination module 300 is used to determine that the battery under test has entered the battery capacity degradation stage when the actual normalized peak change rate is less than the preset battery capacity degradation inflection point threshold.

[0083] Optionally, in one embodiment of this application, it further includes: a second acquisition module, a calculation module, and a determination module.

[0084] The second acquisition module is used to acquire charging data of the target battery during the charging process, provided that the target battery is charged to the target micro-overcharge cutoff voltage value at least twice, before detecting whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold.

[0085] The calculation module is used to calculate the differential incremental capacity value of the target battery under test based on the charging data, and to calculate the normalized peak change rate of the target battery under test based on the differential incremental capacity value.

[0086] The determination module is used to determine the threshold of the battery capacity decay inflection point of the target battery under test based on the normalized peak change rate.

[0087] Optionally, in one embodiment of this application, the determining module includes: a first determining unit, a judging unit, a second determining unit, and a third determining unit.

[0088] The first determining unit is used to determine the initial threshold of the battery capacity decay inflection point of the target battery under test based on the normalized peak change rate.

[0089] The judgment unit is used to determine whether the target battery under test has entered the stage of rapid capacity degradation based on the initial threshold.

[0090] The second determining unit is used to determine the inflection point threshold of battery capacity decay based on the initial threshold when the target battery under test enters the stage of rapid battery capacity decay.

[0091] The third determining unit is used to recharge the target battery under test to the target micro-overcharge cutoff voltage value before the target battery under test enters the battery capacity decay stage, until the target battery under test enters the battery capacity decay stage, so as to obtain a new initial threshold and determine the battery capacity decay inflection point threshold based on the new initial threshold.

[0092] Optionally, in one embodiment of this application, the detection module 200 includes: an acquisition unit, a first calculation unit, and a second calculation unit.

[0093] The acquisition unit is used to acquire the current voltage and current charge value of the battery under test at at least two moments based on actual charging data.

[0094] The first calculation unit is used to calculate the actual incremental capacity value of the battery under test based on the current voltage value and the current charge value.

[0095] The second calculation unit is used to calculate the actual differential incremental capacity value based on the actual incremental capacity value.

[0096] Optionally, in one embodiment of this application, the detection module 200 includes: an extraction unit, a fourth determination unit, a normalization unit, and a third calculation unit.

[0097] The extraction unit is used to extract the target peak value from the actual differential incremental capacity value.

[0098] The fourth determining unit is used to determine the normalized threshold of the battery under test based on the target peak value.

[0099] The normalization unit is used to normalize the actual differential increment capacity value based on the normalization threshold to obtain the normalized peak height.

[0100] The third calculation unit is used to calculate the actual normalized peak change rate based on the normalized peak height.

[0101] It should be noted that the explanation of the aforementioned method embodiment for detecting the inflection point of battery capacity decay also applies to the device for detecting the inflection point of battery capacity decay in this embodiment, and will not be repeated here.

[0102] The battery capacity decay inflection point detection device proposed in this application can collect actual charging data of the battery under test during the charging process after charging the battery to the target micro-overcharge cutoff voltage value at least twice. Based on the actual charging data, it calculates the actual differential incremental capacity value of the battery under test, and then calculates the actual normalized peak value change rate of the battery under test. It then detects whether the actual normalized peak value change rate is less than a preset battery capacity decay inflection point threshold. If it is less, it determines that the battery has entered the battery capacity decay plunge stage. By determining whether the battery has entered the battery capacity decay plunge stage based on the pre-predicted battery capacity decay inflection point threshold, it reduces the influence of interference factors, improves the accuracy of detection, and features simple calculation, high sensitivity, improved detection efficiency, and reduced detection costs. It is suitable for battery management systems to manage capacity and enhance battery safety. Therefore, it solves the technical problems in related technologies, which often rely on a large amount of experimental data or complex model parameter calibration processes, resulting in long testing cycles, high costs, and a lack of systematic solutions integrating electrochemical mechanisms and data characteristics, making it difficult to meet the current needs for accurate battery performance evaluation and efficient analysis.

[0103] Figure 6 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. The electronic device may include: The memory 601, the processor 602, and the computer program stored on the memory 601 and capable of running on the processor 602.

[0104] When the processor 602 executes the program, it implements the method for detecting the inflection point of battery capacity decay provided in the above embodiments.

[0105] Furthermore, electronic devices also include: Communication interface 603 is used for communication between memory 601 and processor 602.

[0106] The memory 601 is used to store computer programs that can run on the processor 602.

[0107] The memory 601 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0108] If the memory 601, processor 602, and communication interface 603 are implemented independently, then the communication interface 603, memory 601, and processor 602 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0109] Optionally, in a specific implementation, if the memory 601, processor 602, and communication interface 603 are integrated on a single chip, then the memory 601, processor 602, and communication interface 603 can communicate with each other through an internal interface.

[0110] The processor 602 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0111] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described method for detecting the inflection point of battery capacity decay.

[0112] This application also provides a computer program product, including a computer program that, when executed, implements the above-described method for detecting the inflection point of battery capacity decay.

[0113] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0115] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0116] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). In addition, the computer-readable medium can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting or otherwise processing as necessary, and then stored in computer memory.

[0117] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0118] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0119] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0120] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for detecting the inflection point of battery capacity decay, characterized in that, Includes the following steps: The actual charging data of the battery under test is collected during the charging process after the battery is charged to the target micro-overcharge cutoff voltage value at least twice. The actual differential incremental capacity value of the battery under test is calculated based on the actual charging data. Based on the actual differential incremental capacity value, the actual normalized peak change rate of the battery under test is calculated. The actual normalized peak change rate is then checked to see if it is less than a preset battery capacity decay inflection point threshold. If the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold, the battery under test is determined to have entered the battery capacity decay plunging stage.

2. The method according to claim 1, characterized in that, Before detecting whether the actual normalized peak change rate is less than a preset battery capacity decay inflection point threshold, the method further includes: The charging data of the target battery under test is collected during the charging process, provided that the target battery under test is charged to the target micro-overcharge cutoff voltage value at least twice. The differential incremental capacity value of the target battery under test is calculated based on the charging data, and the normalized peak change rate of the target battery under test is calculated based on the differential incremental capacity value. Based on the normalized peak change rate, the threshold value of the inflection point of battery capacity decay of the target battery under test is determined.

3. The method according to claim 2, characterized in that, The step of determining the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate includes: Based on the normalized peak change rate, the initial threshold for the inflection point of the battery capacity decay of the target battery under test is determined. Based on the initial threshold, it is determined whether the target battery under test has entered the stage of rapid battery capacity degradation. If the target battery under test enters the stage of rapid capacity decay, the inflection point threshold of battery capacity decay is determined according to the initial threshold. If the target battery under test has not entered the battery capacity degradation drop phase, the target battery under test is recharged to the target micro-overcharge cutoff voltage value until the target battery under test enters the battery capacity degradation drop phase, so as to obtain a new initial threshold, and the battery capacity degradation inflection point threshold is determined according to the new initial threshold.

4. The method according to claim 1, characterized in that, The calculation of the actual differential incremental capacity value of the battery under test based on the actual charging data includes: Based on the actual charging data, obtain the current voltage and current charge value of the battery under test at at least two moments; Based on the current voltage value and the current charge value, calculate the actual incremental capacity value of the battery under test; The actual differential incremental capacity value is calculated based on the actual incremental capacity value.

5. The method according to claim 1, characterized in that, The step of calculating the actual normalized peak change rate of the battery under test based on the actual differential incremental capacity value includes: Extract the target peak value from the actual differential incremental capacity value; The normalized threshold of the battery under test is determined based on the target peak value; Based on the normalization threshold, the actual differential increment capacity value is normalized to obtain the normalized peak height. Based on the normalized peak height, the actual normalized peak change rate is calculated.

6. A device for detecting the inflection point of battery capacity decay, characterized in that, include: The first acquisition module is used to acquire the actual charging data of the battery under test during the charging process, provided that the battery under test is charged to the target micro-overcharge cutoff voltage value at least twice. The detection module is used to calculate the actual differential incremental capacity value of the battery under test based on the actual charging data, and to calculate the actual normalized peak change rate of the battery under test based on the actual differential incremental capacity value, and to detect whether the actual normalized peak change rate is less than a preset battery capacity decay inflection point threshold. The determination module is used to determine that the battery under test has entered the battery capacity degradation stage when the actual normalized peak change rate is less than the preset battery capacity degradation inflection point threshold.

7. The apparatus according to claim 6, characterized in that, Also includes: The second acquisition module is used to acquire charging data of the target battery during the charging process before detecting whether the actual normalized peak change rate is less than the preset battery capacity decay inflection point threshold, provided that the target battery under test is charged to the target micro-overcharge cutoff voltage value at least twice. The calculation module is used to calculate the differential incremental capacity value of the target battery under test based on the charging data, and to calculate the normalized peak change rate of the target battery under test based on the differential incremental capacity value. The determination module is used to determine the battery capacity decay inflection point threshold of the target battery under test based on the normalized peak change rate.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the method for detecting the inflection point of battery capacity decay as described in any one of claims 1-5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method for detecting the inflection point of battery capacity decay as described in any one of claims 1-5.

10. A computer program product, characterized in that, Includes a computer program, which, when executed, is used to implement the method for detecting the inflection point of battery capacity decay as described in any one of claims 1-5.

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