A method, device, equipment and medium for detecting the state of health of a battery

Abstract

The present application relates to the technical field of battery detection, and particularly to a method, device, equipment and medium for detecting the state of health of a battery. The present application uses incremental capacity analysis to obtain an incremental capacity curve during the battery charging process, and then extracts the potential values and height values of three main characteristic peaks therefrom; according to the target ambient temperature, a normal threshold range for these characteristic parameters is set; the measured peak parameters are compared with the corresponding threshold ranges, and only when all parameters are within the threshold ranges, it is determined that the battery is in a healthy state at this temperature. Among them, the incremental capacity curve can better reflect the actual internal state change of the battery, and the potential values and height values of the three main characteristic peaks can intuitively reflect the aging degree of the battery. At the same time, through the comprehensive comparison of the potential values and height values, the problem of misjudgment prone to occur in the existing voltage monitoring method during battery aging is solved.

Description

Technical Field

[0001] The present application relates to the technical field of battery detection, and in particular, to a method, device, equipment and medium for detecting the state of health of a battery. Background Art

[0002] With the continuous development of the automation and intelligence of the power system, the distribution network feeder terminal, as an important line protection and communication device, plays an increasingly crucial role in the operation of the distribution network. The distribution network feeder terminal can monitor the line operation status in real time, detect various faults, and perform protection operations according to the fault conditions. At the same time, it can also upload the line data to the system master station to achieve remote monitoring and control. A reliable power supply battery is the basis for ensuring the normal operation of the distribution network feeder terminal.

[0003] At present, most of the distribution network feeder terminals in operation monitor the state of health of the power supply battery by monitoring the battery voltage. When the battery voltage is within a reasonable range, it is determined that the battery is in a normal state. The principle of this method is based on the fact that under normal battery capacity, the voltage level can reflect the battery health degree. The voltage monitoring method is simple to operate and can be achieved only by collecting the voltage value and comparing it with the threshold range.

[0004] However, relying solely on voltage monitoring has obvious defects. Since the battery capacity will inevitably decay during use, when the capacity drops to a certain extent, the battery voltage will change rapidly. At this time, the voltage monitoring will lose accuracy, and the charging control logic of the distribution network feeder terminal will be disrupted, resulting in misjudgment and operation, and thus continuously repeating the charge-discharge cycle, exacerbating battery loss, and ultimately leading to the paralysis of the entire FTU system. Therefore, the existing voltage monitoring method cannot meet the requirements of the distribution network feeder terminal for evaluating the state of health of the power supply battery, and this situation needs to be further improved. Summary of the Invention

[0005] In order to solve the problem that the existing voltage monitoring method cannot meet the requirements of the distribution network feeder terminal for evaluating the state of health of the power supply battery, the present application provides a method, device, equipment and medium for detecting the state of health of a battery, and adopts the following technical solutions:

[0006] In the first aspect, the present application provides a method for detecting the state of health of a battery, including the following steps:

[0007] Obtain the battery charge current-voltage curve at the target ambient temperature value;

[0008] Based on the battery charge current-voltage curve, use capacity increment analysis to obtain the capacity increment curve of the battery charge at the target ambient temperature value, and the capacity increment curve includes a first peak, a second peak and a third peak;

[0009] Determine the potential values and height values of the first peak, the second peak, and the third peak corresponding to the target ambient temperature value;

[0010] According to the target ambient temperature value, obtain the potential difference threshold range between the first peak and the second peak, the potential difference threshold range between the second peak and the third peak, the height difference threshold range between the first peak and the second peak, and the height difference threshold range between the second peak and the third peak;

[0011] Calculate the actual potential difference between the first peak and the second peak, the actual potential difference between the second peak and the third peak, the actual height difference between the first peak and the second peak, and the actual height difference between the second peak and the third peak at the target ambient temperature value;

[0012] Judge whether the actual potential differences are respectively within the corresponding potential difference threshold ranges, and judge whether the actual height differences are within the corresponding height difference threshold ranges. If both the actual potential differences and the actual height differences are within the corresponding threshold ranges, determine that the health state of the battery is normal at the target ambient temperature value; otherwise, determine that the health state of the battery is abnormal.

[0013] By adopting the above technical solution, the present application uses capacity increment analysis to obtain the capacity increment curve during the battery charging process, and then extracts the potential values and height values of three main characteristic peaks therefrom; according to the target ambient temperature, sets the normal threshold ranges of these characteristic parameters; compares the measured peak parameters with the corresponding threshold ranges. Only when all parameters are within the threshold ranges, it is determined that the battery is in a healthy state at this temperature. Among them, the capacity increment curve can better reflect the actual internal state change of the battery, the potential values and height values of the three main characteristic peaks can intuitively reflect the aging degree of the battery, and at the same time, through the comprehensive comparison of the potential values and height values, the problem of misjudgment prone to occur in the existing voltage monitoring method during battery aging is solved.

[0014] Optionally, the method further includes the following steps:

[0015] Obtain a set of preset ambient temperature values;

[0016] For each ambient temperature value in the set of preset ambient temperature values, respectively determine the health state of the battery at each ambient temperature value;

[0017] When the health states of the battery are all normal at all ambient temperature values, determine that the overall health state of the battery is normal; otherwise, determine that the overall health state of the battery is abnormal.

[0018] By adopting the above technical solution, the present application presets a set of ambient temperature values to be evaluated. For each temperature value, the health state of the battery at this temperature is determined respectively according to the aforementioned method based on the characteristic parameters of the capacity increment curve. Only when the battery is judged to be healthy in all temperature conditions, the overall health state of the battery is finally confirmed to be normal; otherwise, it is judged to be abnormal. Through comprehensive judgment under multiple temperature conditions, the actual health level of the battery in various possible environments can be comprehensively reflected, avoiding the deviation caused by the evaluation of local temperature conditions, thereby further improving the accuracy and reliability of the judgment.

[0019] Optionally, after determining that the health state of the battery at the target ambient temperature value is normal, or determining that the health state of the battery is abnormal, the method further includes the following steps:

[0020] Calculate the actual area between the first peak and the second peak, and the actual area between the second peak and the third peak at the target ambient temperature;

[0021] According to the target ambient temperature value, obtain the area threshold range between the first peak and the second peak, and the area threshold range between the second peak and the third peak;

[0022] Judge whether the actual area is respectively within the corresponding area threshold range. If the actual area is within the corresponding threshold range, it is determined that the area criterion result at the target ambient temperature value is normal; otherwise, it is determined that the area criterion result is abnormal;

[0023] According to the area criterion result, evaluate the health level of the battery at the target ambient temperature value and record the evaluation result.

[0024] By adopting the above technical solution, on the basis of having determined that the battery is in a normal or abnormal state at a certain temperature, the present application further calculates the area value between two adjacent characteristic peaks on the capacity increment curve; obtains the normal threshold range of this area value according to the target temperature; compares the measured area value with the threshold range to judge whether the area criterion is normal; then finely evaluates the health level of the battery at this temperature according to the area criterion result and records the result, making use of the area characteristic information on the capacity increment curve, increasing the amount of information for evaluation; and more finely distinguishing the change trend of the battery health level through the area value.

[0025] Optionally, before obtaining the battery charge current-voltage curve at the target ambient temperature value, the method further includes the following steps:

[0026] Periodically obtain each instantaneous current value of the battery charge and discharge at the target ambient temperature value;

[0027] Judge whether each instantaneous current value is within the preset normal range;

[0028] If the instantaneous current values exceed the normal range, determine the current adjustment factor corresponding to the battery according to the target ambient temperature value;

[0029] Calculate the calibrated actual instantaneous current values according to the current adjustment factor and the instantaneous current values.

[0030] By adopting the above technical solution, since the actual instantaneous current values of the battery during charging and discharging may be affected by various factors and deviate from the normal range, this application periodically obtains the instantaneous current values of the battery charging and discharging at the target ambient temperature to determine whether they are within the normal range; if there are abnormal values beyond the range, determine the corresponding current adjustment factor according to the current temperature, and use this factor to calibrate the abnormal current values to obtain the actual instantaneous current values, thereby eliminating the influence of current abnormal values on subsequent analysis.

[0031] Optionally, the method further includes the following steps:

[0032] Obtain the rated capacity of the battery corresponding to the target ambient temperature value;

[0033] Calculate the capacity loss rate between the actual charging capacity obtained based on the capacity increment curve and the rated capacity of the battery; predict the remaining cycle life of the battery according to the capacity loss rate.

[0034] By adopting the above technical solution, this application uses the capacity increment curve to obtain the actual charging capacity of the battery at the target temperature, compares it with the rated capacity of the battery, and calculates the capacity loss rate; predicts the remaining available cycle times, that is, the remaining life, according to this loss rate using an empirical model, providing a basis for the subsequent use management and timely replacement of the battery, reducing the risk of system paralysis caused by the complete failure of the battery, and ensuring the long-term reliable operation of the system.

[0035] Optionally, after predicting the remaining cycle life of the battery according to the capacity loss rate, the method further includes the following steps:

[0036] Judge whether the remaining cycle life is less than a preset critical remaining cycle life;

[0037] If the remaining cycle life is less than the preset critical remaining cycle life, determine that the battery has reached the end of its service life and issue a prompt to replace the battery with a new one.

[0038] By adopting the above technical solution, this application preset a critical value of the remaining cycle life in advance; compare the remaining life value predicted based on the capacity loss rate with the critical value; once the predicted value is lower than the critical value, determine that the battery has reached the end of its service life, and immediately issue a prompt to replace the battery with a new one, prompting the user to replace it in time, ensuring the continuous and reliable operation of the system.

[0039] Optionally, according to the capacity loss rate, the remaining cycle life N of the battery is predicted as N = a*e^(b*(1 - Q)) + c, where N is the remaining cycle life, Q is the capacity loss rate during cycling, and a, b, and c are fitting coefficients.

[0040] By adopting the above technical solution, the present application establishes a mathematical relationship between the remaining life and the capacity loss rate, and the prediction result is more accurate and reliable; the remaining cycle life is quickly predicted through a simple formula, which is easy to implement in software and hardware; at the same time, the accuracy can be continuously optimized and improved according to new data.

[0041] In a second aspect, the present application provides a battery health state detection system, including:

[0042] A charging curve acquisition module, configured to acquire a battery charging current-voltage curve at a target ambient temperature value;

[0043] An incremental capacity curve acquisition module, configured to obtain a capacity increment curve of battery charging at the target ambient temperature value based on the battery charging current-voltage curve by using capacity increment analysis, where the capacity increment curve includes a first peak, a second peak, and a third peak;

[0044] A numerical value acquisition module, configured to determine the potential values and height values of the corresponding first peak, second peak, and third peak at the target ambient temperature value;

[0045] A difference range acquisition module, configured to obtain a potential difference threshold range between the first peak and the second peak, a potential difference threshold range between the second peak and the third peak, a height difference threshold range between the first peak and the second peak, and a height difference threshold range between the second peak and the third peak according to the target ambient temperature value;

[0046] An actual difference acquisition module, configured to calculate the actual potential difference between the first peak and the second peak, the actual potential difference between the second peak and the third peak, the actual height difference between the first peak and the second peak, and the actual height difference between the second peak and the third peak at the target ambient temperature value;

[0047] A health state judgment module, configured to judge whether the actual potential difference is respectively within the corresponding potential difference threshold range, and judge whether the actual height difference is within the corresponding height difference threshold range. If both the actual potential difference and the actual height difference are within the corresponding threshold ranges, it is determined that the health state of the battery at the target ambient temperature value is normal, otherwise it is determined that the health state of the battery is abnormal.

[0048] In a third aspect, the present application provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the above battery health status detection method are implemented.

[0049] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above battery health status detection method are implemented.

[0050] In summary, the present application includes at least one of the following beneficial technical effects:

[0051] 1. The present application uses capacity increment analysis to obtain the capacity increment curve during the battery charging process, and then extracts the potential values and height values of three main characteristic peaks therefrom; according to the target ambient temperature, sets the normal threshold range of these characteristic parameters; compares the measured peak parameters with the corresponding threshold range. Only when all parameters are within the threshold range, it is determined that the battery is in a healthy state at this temperature. Among them, the capacity increment curve can better reflect the actual internal state change of the battery, and the potential values and height values of the three main characteristic peaks can intuitively reflect the aging degree of the battery. At the same time, through the comprehensive comparison of the potential values and height values, the problem of misjudgment easily occurring in the existing voltage monitoring method during battery aging is solved;

[0052] 2. The present application presets a set of ambient temperature values to be evaluated. For each temperature value, the health state of the battery at this temperature is determined respectively according to the method based on the characteristic parameters of the capacity increment curve described above; only when the battery is determined to be healthy in all temperature cases, the overall health state of the battery is finally confirmed to be normal, otherwise it is determined to be abnormal. Through comprehensive judgment under multiple temperature conditions, the actual health level of the battery in various possible environments can be comprehensively reflected, avoiding the deviation caused by the evaluation of local temperature conditions, thereby further improving the accuracy and reliability of the judgment;

[0053] 3. On the basis of having determined that the battery is in a normal or abnormal state at a certain temperature, the present application further calculates the area value between two adjacent characteristic peaks on the capacity increment curve; obtains the normal threshold range of this area value according to the target temperature; compares the measured area value with the threshold range to judge whether this area criterion is normal; then finely evaluates the health level of the battery at this temperature according to the result of the area criterion and records the result. The area characteristic information on the capacity increment curve is utilized, improving the amount of information for evaluation; the change trend of the battery health level is more finely distinguished through the area value. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a schematic flowchart of a battery health status detection method according to an embodiment of the present application;

[0055] Figure 2 It is a schematic diagram of the battery charging IC curve at 25°C in a battery health state detection method according to an embodiment of the present application;

[0056] Figure 3 It is a schematic diagram of the battery charging IC curve at different temperatures in a battery health state detection method according to an embodiment of the present application;

[0057] Figure 4 It is a schematic diagram of the process for determining the overall health state in a battery health state detection method according to an embodiment of the present application;

[0058] Figure 5 It is a schematic diagram of the process for performing area criterion in a battery health state detection method according to an embodiment of the present application;

[0059] Figure 6 It is a schematic diagram of the process for adjusting current in a battery health state detection method according to an embodiment of the present application;

[0060] Figure 7 It is a schematic diagram of the process for predicting the remaining life in a battery health state detection method according to an embodiment of the present application;

[0061] Figure 8 It is a schematic diagram of the modules of a battery health state detection system according to an embodiment of the present application;

[0062] Figure 9 It is an internal structure diagram of an electronic device according to an embodiment of the present application. Detailed implementation manners

[0063] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of the present application, the singular forms "a", "an", "the", "above-mentioned", "said", and "this" are also intended to include the plural forms, unless there is a clear indication to the contrary in the context. It should also be understood that the term "and / or" used in the present application refers to any or all possible combinations including one or more of the listed items.

[0064] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0065] The following further describes the embodiments of the present application in detail with reference to the accompanying drawings of the specification.

[0066] In a first aspect, the present application provides a method for detecting the state of health of a battery, with reference to Figure 1 , including the following steps:

[0067] S11. Obtain the battery charging current-voltage curve at the target ambient temperature value.

[0068] In this embodiment, the battery charging current-voltage curve refers to the curve of the change in the battery terminal voltage with the charging time when the battery is charged with a constant current in a specific temperature environment.

[0069] Specifically, place the battery in an environmental chamber or incubator that can control and maintain a specific temperature, use a constant current power supply to charge the battery with an appropriate charging current, and synchronously record the change process of the battery terminal voltage with the charging time, so as to obtain the battery charging current-voltage curve data at the target ambient temperature value.

[0070] S12. Based on the battery charging current-voltage curve, use incremental capacity analysis to obtain the incremental capacity curve of the battery charging at the target ambient temperature value. The incremental capacity curve includes a first peak, a second peak, and a third peak.

[0071] In this embodiment, the incremental capacity curve is obtained by incremental capacity analysis through the voltage plateau conversion on the charge-discharge curve, and usually includes several peak points corresponding to different phase change reactions of the battery.

[0072] Specifically, perform numerical differentiation processing on the obtained charging current-voltage curve data to obtain the original data of the incremental capacity curve. After data processing such as smoothing filtering, an incremental capacity curve image including multiple peaks can be drawn. Generally, this curve includes at least 3 significant peak points, corresponding to 3 main insertion and clamping phase change reactions of the battery respectively.

[0073] S13. Determine the potential values and height values of the first peak, the second peak, and the third peak corresponding to the target ambient temperature value.

[0074] Among them, the potential value refers to the battery terminal voltage value corresponding to each peak point on the incremental capacity curve. The height value refers to the peak value of each peak, reflecting the relative intensity of this reaction stage.

[0075] Specifically, use a peak detection algorithm to search for and lock the first 3 most significant peak points in the obtained incremental capacity curve data, and record the corresponding voltage potential values and peak height values respectively as the potential values and height values of the first peak, the second peak, and the third peak.

[0076] In one embodiment, through a large number of battery charging experiments, the incremental capacity curve, that is, the IC curve, at the target ambient temperature value of 25°C is calculated as Figure 2As shown, it can be seen that the IC curve includes Peak 1, Peak 2, and Peak 3, corresponding to the first peak, the second peak, and the third peak respectively. As Figure 3 shown, due to different ambient temperatures, the height differences between the three peaks, the potentials of the three peaks, and the potential differences between the three peaks of the battery charging IC curve will vary. The specific IC curve calculation formula is: where I is the current, V is the voltage, and Q is the battery capacity. Therefore, the height differences and potential differences between the two peaks can be fully utilized to evaluate the battery health status.

[0077] S14. According to the target ambient temperature value, obtain the potential difference threshold ranges between the first peak and the second peak, between the second peak and the third peak, the height difference threshold range between the first peak and the second peak, and the height difference threshold range between the second peak and the third peak.

[0078] Among them, the potential difference threshold range refers to the normal potential difference range between the first and second peaks and between the second and third peaks of a healthy battery at this temperature. The height difference threshold range refers to the normal height difference range between the first and second peaks and between the second and third peaks of a healthy battery. These threshold ranges can be determined by modeling a large number of measured data.

[0079] Specifically, using prior knowledge or experimental data, model and analyze the capacity increment curves of healthy batteries at different temperatures, obtain the normal potential difference ranges and height difference ranges between the first and second peaks and between the second and third peaks at each temperature point, and store them in the form of a lookup table for subsequent criterion use.

[0080] S15. Calculate the actual potential difference between the first peak and the second peak, the actual potential difference between the second peak and the third peak, the actual height difference between the first peak and the second peak, and the actual height difference between the second peak and the third peak at the target ambient temperature value.

[0081] In this embodiment, by comparing the measured potential difference and height difference with the previously obtained normal threshold ranges, it is determined whether the health status of the battery at the target ambient temperature value is normal.

[0082] S16. Determine whether the actual potential differences are respectively within the corresponding potential difference threshold ranges, and determine whether the actual height differences are within the corresponding height difference threshold ranges. If both the actual potential differences and the actual height differences are within the corresponding threshold ranges, it is determined that the health status of the battery at the target ambient temperature value is normal; otherwise, it is determined that the health status of the battery is abnormal.

[0083] Specifically, the actual potential differences between the first and second peaks and between the second and third peaks are respectively compared with the corresponding potential difference threshold ranges. If both fall within the ranges, the potential difference is normal. The actual height differences between the first and second peaks and between the second and third peaks are respectively compared with the corresponding height difference threshold ranges. If both fall within the ranges, the height difference is normal. Only when both the potential difference and the height difference are normal can it be confirmed that the health state of the battery at this temperature is normal; otherwise, the health state of the battery is abnormal.

[0084] It can be understood that during the judgment process of step S16, it is possible to first judge whether the actual potential difference is within the corresponding potential difference threshold range. If it is within the corresponding potential difference threshold range, then judge whether the actual height difference is within the corresponding height difference threshold range. It is also possible to first judge the actual height difference and then judge the actual potential difference, and there is no limitation on this.

[0085] For example, in one embodiment, first judge whether the actual potential difference is within the corresponding potential difference threshold range. If it is within the corresponding potential difference threshold range, then judge whether the actual height difference is within the corresponding height difference threshold range. First, based on a large number of battery charge and discharge experiments at different temperatures, the IC curve is obtained by using capacity increment analysis according to the above method, and the empirical values obtained from the curve are as follows:

[0086]

[0087] From the above empirical values, the result can be obtained that when the ambient temperature decreases, the 3rd peak shows a tendency to shift to the left, and when the ambient temperature increases, the 3rd peak shows a tendency to shift to the right.

[0088] Then, the ambient temperature T is obtained through a temperature sensor, and the thresholds of the potential differences between the two peaks are determined as follows:

[0089] U t1 ∈[0.07, 1]U t2 ∈[0.01, 0.06] T ∈ [24, 26];

[0090] U t1 ∈[0.07, 1]U t2 ∈[0.01, 0.04] T ≤ 23;

[0091] U t1 ∈[0.07, 1]U t2 ∈[0.01, 0.08] T ≥ 27, where U t1 is the potential difference threshold between the 1st peak and the 2nd peak at the target ambient temperature value T, and U t2 is the potential difference threshold between the 2nd peak and the 3rd peak at the target ambient temperature value T.

[0092] First, judge the potential difference and calculate the potential difference U between the 1st peak and the 2nd peak12 The potential difference U between the 2nd peak and the 3rd peak 23 , and based on different temperatures, judge U 12 and U 23 Whether it is within the threshold range. If it is not within the range, it is considered that the battery health is abnormal. Taking the normal temperature T = 25°C as an example, at this time U t1 ∈[0.07,1]U t2 ∈[0.01,0.06]; Obtain the potentials of the 1st, 2nd, and 3rd peaks from the IC curve, and calculate the potential difference U 12 、U 23 . Evaluate the battery health status U 12 ∈U t1 U 23 ∈U t2 . If the above conditions are met, enter the next judgment condition; if the above conditions are not met, it is considered that the battery health is abnormal.

[0093] The next judgment condition starts to judge the height difference. First, based on a large number of battery charge and discharge experiments at different temperatures, use the above method to obtain the IC curve by capacity increment analysis. The height empirical values obtained from the curve are as follows:

[0094]

[0095] From the above empirical values, the result can be obtained: when the ambient temperature decreases, the peak values of the 3 peaks show a decreasing trend; when the ambient temperature increases, the peak values of the 3 peaks show an increasing trend.

[0096] Then, through a large number of battery charge and discharge experiments, determine the height difference thresholds between two peaks as follows:

[0097] H t1 ∈[7,15]H t2 ∈[2,8] T∈[24,26];

[0098] H t1 ∈[6.6,11.9]H t2 ∈[1.3,5.2] T≤23;

[0099] H t1 ∈[8,13.6]H t2 ∈[5,5.2] T≥27, Among them, H t1 is the height difference threshold between the 1st peak value and the 2nd peak value at the temperature; H t2 is the height difference threshold between the 2nd peak value and the 3rd peak value at the temperature.

[0100] Calculate the height difference H between the 1st peak and the 2nd peak 12 、the height difference H between the 2nd peak and the 3rd peak 23, select the height difference threshold H according to different temperatures t1 or H t2 , judge H 12 and H 23 whether it is within the threshold range. If it is not within the range, it is considered that the battery health is abnormal. Taking the normal temperature T = 25°C as an example, at this time H t1 ∈[7,15], H t2 ∈[2,8]; Obtain the heights of the 1st, 2nd, and 3rd peaks from the IC curve, and calculate the height difference H 12 and H 23 . Evaluate the battery health status H 12 ∈H t1 H 23 ∈H t2 . If the above conditions are met, the battery is considered healthy; otherwise, the battery is considered abnormal.

[0101] In one embodiment, referring to Figure 4 , the method further includes the following steps:

[0102] S41. Obtain a set of preset ambient temperature values.

[0103] In this embodiment, a set of preset ambient temperature values refers to a series of typical working temperature points that the battery may encounter in actual applications. These temperature points can be preset based on experience or data statistics.

[0104] Specifically, according to the expected application scenarios and conditions of the battery, determine a temperature range, such as -10°C - 50°C, and then evenly select several representative temperature points within this range, such as -10°C, 0°C, 101°C, 20°C, 25°C, 30°C, 40°C, 50°C, etc., to form a set of preset ambient temperature value sets.

[0105] S42. For each ambient temperature value in the set of preset ambient temperature values, determine the health status of the battery at each ambient temperature value respectively.

[0106] In this embodiment, the method for determining the battery health status at each preset temperature value can adopt the aforementioned method based on the analysis of the capacity increment curve.

[0107] Specifically, for each temperature point in the temperature value set, repeat steps S11 - S16: first obtain the battery charging curve at this temperature, analyze to obtain the capacity increment curve and peak parameters, and then compare the peak parameters with the threshold range corresponding to this temperature point to determine whether the health status of the battery is normal at this temperature point.

[0108] S43. When the health status of the battery is normal at all ambient temperature values, determine that the overall health status of the battery is normal; otherwise, determine that the overall health status of the battery is abnormal.

[0109] In this embodiment, by checking whether the battery is in a healthy state at all preset temperature points, the comprehensive health state of the battery within the entire operating temperature range can be comprehensively evaluated.

[0110] Specifically, by setting a flag bit and initializing it to overall normal. Then, check the health state determined at each temperature point one by one. Once it is found that any temperature point is abnormal, set the flag bit to overall abnormal and abort the subsequent checks.

[0111] In one embodiment, referring to Figure 5 , after determining that the health state of the battery at the target ambient temperature value is normal, or determining that the health state of the battery is abnormal, the method further includes the following steps:

[0112] S51. Calculate the actual area between the first peak and the second peak, and the actual area between the second peak and the third peak at the target ambient temperature.

[0113] Among them, as Figure 2 shown, the IC curve not only includes characteristics such as the height of peak No. 1, the height of peak No. 2, the height of peak No. 3, the height difference between the two peaks, the potential corresponding to the peak value, and the potential difference between the two peaks, but also includes the characteristic of the area enclosed by the two peaks.

[0114] In this embodiment, the actual area refers to the area enclosed between the first and second peaks and the second and third peaks on the capacity increment curve. This area value is related to the lithium insertion / delithium capacity of the positive and negative electrode materials of the battery and is another important parameter for evaluating the health state of the battery.

[0115] Specifically, using the method of numerical integration, calculate the area of the curve region between the first and second peaks and the second and third peaks to obtain their actual area values. For example, discrete point numerical integration, rectangular region estimation or other numerical integration algorithms can be used.

[0116] S52. According to the target ambient temperature value, obtain the area threshold range between the first peak and the second peak, and the area threshold range between the second peak and the third peak.

[0117] In this embodiment, the area threshold range refers to the normal area value range between the first and second peaks and the second and third peaks of a healthy battery at this temperature. These threshold ranges can be determined by modeling a large amount of measured data.

[0118] Specifically, prior knowledge or experimental data can be used to perform modeling analysis on the capacity increment curves of healthy batteries at different temperatures, obtain the normal area value ranges between the first and second peaks and the second and third peaks at each temperature point, and store them in the form of a lookup table or the like.

[0119] S53. Determine whether the actual area is within the corresponding area threshold range respectively. If the actual area is within the corresponding threshold range, it is determined that the area criterion result is normal at the target ambient temperature value; otherwise, it is determined that the area criterion result is abnormal.

[0120] In this embodiment, by comparing the measured area value with the pre-obtained normal threshold range, it can be determined whether the area criterion result of the battery at the current temperature is normal.

[0121] Specifically, compare the actual area values between the first and second peaks and between the second and third peaks with the corresponding area threshold ranges respectively. If both fall within the ranges, the area criterion is normal; otherwise, the area criterion is abnormal.

[0122] S54. According to the area criterion result, evaluate the health level of the battery at the target ambient temperature value and record the evaluation result.

[0123] In this embodiment, the health level of the battery can be divided into multiple levels, such as excellent, normal, poor, serious, etc. The evaluation result will be recorded in the battery management system.

[0124] Specifically, combining the previously determined battery health status (normal or abnormal) and the area criterion result (normal or abnormal), comprehensively evaluate the battery health level according to the pre-set rules. For example, "status normal + area normal" is the excellent level, "status normal + area abnormal" is the normal level, "status abnormal" is the poor or serious level, etc.

[0125] In one embodiment, before referring to Figure 6 , obtaining the battery charging current-voltage curve at the target ambient temperature value, the method further includes the following steps:

[0126] S61. Periodically obtain each instantaneous current value of the battery charging and discharging at the target ambient temperature value.

[0127] In this embodiment, the instantaneous current value refers to the real-time current value measured at each time point during the actual charging and discharging process of the battery.

[0128] Specifically, a high-precision current sensor or detection circuit connected to the battery management system can be used to sample the charging and discharging current of the battery at a preset period (such as every 10 milliseconds) to obtain a series of instantaneous current data.

[0129] S62. Determine whether each instantaneous current value is within the preset normal range.

[0130] In this embodiment, the normal range refers to the normal operating interval of the current preset according to factors such as the rated capacity and working mode of the battery. If the current is too high or too low, it may cause battery damage.

[0131] S63. If each instantaneous current value exceeds the normal range, determine the current adjustment factor corresponding to the battery according to the target ambient temperature value.

[0132] In this embodiment, the current adjustment factor is a temperature-related correction coefficient used to calibrate the actual current value to bring it back to the normal operating range.

[0133] Specifically, a mapping relationship table between temperature and the current adjustment factor is established in advance. When abnormal current is detected, the corresponding current adjustment factor is obtained by looking up the table according to the current temperature value. The calculation of the current adjustment factor can use a large number of measured data and perform regression fitting in combination with the battery electrochemical model.

[0134] S64. Calculate the calibrated actual instantaneous current values according to the current adjustment factor and each instantaneous current value.

[0135] In this embodiment, by operating the detected abnormal current value with the corresponding current adjustment factor, the actual instantaneous current value after temperature calibration can be obtained to ensure that they fall within the normal operating range.

[0136] Specifically, multiply each abnormal instantaneous current value by the corresponding current adjustment factor to obtain a series of calibrated actual instantaneous current data.

[0137] In one embodiment, referring to Figure 7 , the method further includes the following steps:

[0138] S71. Obtain the rated capacity of the battery corresponding to the target ambient temperature value.

[0139] In this embodiment, the rated capacity of the battery refers to the nominal capacity value that the battery can provide when fully charged at the target ambient temperature, usually given by the battery manufacturer.

[0140] Specifically, a lookup table between temperature and the rated capacity of the battery is established in advance. When predicting the remaining life, the corresponding rated capacity reference value is queried and obtained from the table according to the current temperature value.

[0141] S72. Calculate the capacity loss rate between the actual charging capacity obtained based on the capacity increment curve and the rated capacity of the battery.

[0142] In this embodiment, the actual charging capacity can be obtained by integrating the area value of the capacity increment curve, which reflects the aging degree of the battery.

[0143] Specifically, numerically integrate the actual area values between the first and second peaks and between the second and third peaks respectively to obtain the corresponding actual charging capacity values. Then compare the actual charging capacity value with the rated capacity of the battery at the current temperature to calculate the capacity loss rate.

[0144] S73. Predict the remaining cycle life of the battery according to the capacity loss rate.

[0145] In this embodiment, the remaining cycle life of the battery is inversely proportional to its capacity loss rate. The higher the loss rate, the shorter the remaining life.

[0146] Specifically, according to the capacity loss rate, predict the remaining cycle life of the battery \(N = a\times e^{b\times(1 - Q)}+c\), where \(N\) is the remaining cycle life, \(Q\) is the capacity loss rate during cycling, and \(a\), \(b\), and \(c\) are fitting coefficients. By establishing the mathematical relationship between the remaining cycle life and the capacity loss rate, the prediction result is more accurate and reliable; the remaining cycle life can be quickly predicted through a simple formula, which is easy to implement in software and hardware; at the same time, the accuracy can be continuously optimized and improved according to new data.

[0147] S74. Determine whether the remaining cycle life is less than the preset critical remaining cycle life.

[0148] S75. If the remaining cycle life is less than the preset critical remaining cycle life, it is determined that the battery has reached the end of its service life, and a prompt to replace the new battery is issued.

[0149] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0150] In a second aspect, the present application provides a battery health state detection system. The battery health state detection system of the present application will be described below in combination with the above battery health state detection method.

[0151] Refer to Figure 8 , a battery health state detection system, comprising:

[0152] A charging curve acquisition module, configured to acquire a battery charging current-voltage curve at a target ambient temperature value;

[0153] An incremental capacity curve acquisition module, configured to obtain a capacity increment curve of battery charging at a target ambient temperature value by using capacity increment analysis based on the battery charging current-voltage curve. The capacity increment curve includes a first peak, a second peak, and a third peak; a numerical value acquisition module, configured to determine the potential values and height values of the corresponding first peak, second peak, and third peak at the target ambient temperature value;

[0154] The difference range acquisition module is used to obtain the potential difference threshold range between the first peak and the second peak, the potential difference threshold range between the second peak and the third peak, the height difference threshold range between the first peak and the second peak, and the height difference threshold range between the second peak and the third peak according to the target ambient temperature value;

[0155] The actual difference acquisition module is used to calculate the actual potential difference between the first peak and the second peak, the actual potential difference between the second peak and the third peak, the actual height difference between the first peak and the second peak, and the actual height difference between the second peak and the third peak at the target ambient temperature value;

[0156] The health status judgment module is used to judge whether the actual potential differences are respectively within the corresponding potential difference threshold ranges, and judge whether the actual height differences are within the corresponding height difference threshold ranges. If both the actual potential differences and the actual height differences are within the corresponding threshold ranges, it is determined that the health status of the battery is normal at the target ambient temperature value, otherwise it is determined that the health status of the battery is abnormal.

[0157] In one embodiment, the system further includes:

[0158] The ambient temperature value acquisition module is used to acquire a preset set of ambient temperature values;

[0159] The health status determination module is used to respectively determine the health status of the battery at each ambient temperature value in the preset set of ambient temperature values;

[0160] The overall health status determination module is used to determine that the overall health status of the battery is normal when the health status of the battery is normal at all ambient temperature values, otherwise it is determined that the overall health status of the battery is abnormal.

[0161] In one embodiment, the system further includes:

[0162] The actual area calculation module is used to calculate the actual area between the first peak and the second peak, and the actual area between the second peak and the third peak at the target ambient temperature;

[0163] The area threshold range acquisition module is used to acquire the area threshold range between the first peak and the second peak, and the area threshold range between the second peak and the third peak according to the target ambient temperature value;

[0164] The area criterion module is used to judge whether the actual areas are respectively within the corresponding area threshold ranges. If the actual areas are within the corresponding threshold ranges, it is determined that the area criterion result is normal at the target ambient temperature value, otherwise it is determined that the area criterion result is abnormal;

[0165] The health level evaluation module is used to evaluate the health level of the battery at the target ambient temperature value according to the area criterion result and record the evaluation result.

[0166] In one embodiment, the system further includes:

[0167] An instantaneous current value acquisition module, configured to periodically acquire each instantaneous current value of the battery during charging and discharging at a target ambient temperature value;

[0168] An instantaneous current value judgment module, configured to judge whether each instantaneous current value is within a preset normal range;

[0169] A current adjustment factor determination module, configured to, if each instantaneous current value exceeds the normal range, determine a current adjustment factor corresponding to the battery according to the target ambient temperature value;

[0170] An actual instantaneous current value calibration module, configured to calculate each calibrated actual instantaneous current value according to the current adjustment factor and each instantaneous current value.

[0171] In one embodiment, the system further includes:

[0172] A rated capacity acquisition module, configured to acquire the rated capacity of the battery corresponding to the target ambient temperature value;

[0173] A capacity loss rate calculation module, configured to calculate a capacity loss rate between the actual charging capacity obtained based on the capacity increment curve and the rated capacity of the battery;

[0174] A remaining cycle life prediction module, configured to predict the remaining cycle life of the battery according to the capacity loss rate.

[0175] Specifically, according to the capacity loss rate, the remaining cycle life N of the battery is predicted as N = a * e^(b * (1 - Q)) + c, where N is the remaining cycle life, Q is the capacity loss rate during cycling, and a, b, and c are fitting coefficients.

[0176] A remaining cycle life judgment module, configured to judge whether the remaining cycle life is less than a preset critical remaining cycle life; a battery replacement prompt module, configured to, if the remaining cycle life is less than the preset critical remaining cycle life, determine that the battery has reached the end of its service life and issue a prompt to replace the battery with a new one.

[0177] In one embodiment, the present application provides an electronic device, which may be a server, and its internal structure diagram may be as shown in Figure 9As shown. The electronic device includes a processor, a memory, and a network interface connected via a system bus. Among them, the processor of the electronic device is used to provide computing and control capabilities. The memory of the electronic device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the electronic device is used to store data. The network interface of the electronic device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, it implements a method for detecting the health state of a battery.

[0178] Those skilled in the art can understand that Figure 9 the structure shown in is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the electronic device to which the solution of this application is applied. The specific electronic device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0179] In one embodiment, an electronic device is further provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in the above method embodiments are implemented.

[0180] Those of ordinary skill in the art can understand that all or part of the processes of implementing the above method embodiments can be completed by instructing relevant hardware through a computer program. The above computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above method embodiments. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in this application may include at least one of non-volatile and volatile memories. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical memory, etc. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0181] The above are all the preferred embodiments of this application. The protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A method for detecting the state of health of a battery, characterized in that, It includes the following steps: Obtain the battery charging current-voltage curve at the target ambient temperature value; Based on the battery charging current-voltage curve, use incremental capacity analysis to obtain the incremental capacity curve of battery charging at the target ambient temperature value, and the incremental capacity curve includes a first peak, a second peak and a third peak; Determine the potential values and height values of the first peak, the second peak and the third peak corresponding to the target ambient temperature value; According to the target ambient temperature value, obtain the potential difference threshold range between the first peak and the second peak, the potential difference threshold range between the second peak and the third peak, the height difference threshold range between the first peak and the second peak, and the height difference threshold range between the second peak and the third peak; Calculate the actual potential difference between the first peak and the second peak, the actual potential difference between the second peak and the third peak, the actual height difference between the first peak and the second peak, and the actual height difference between the second peak and the third peak at the target ambient temperature value; Judge whether the actual potential differences are respectively within the corresponding potential difference threshold ranges, and judge whether the actual height differences are within the corresponding height difference threshold ranges. If both the actual potential differences and the actual height differences are within the corresponding threshold ranges, determine that the health state of the battery at the target ambient temperature value is normal, otherwise determine that the health state of the battery is abnormal.

2. The battery health state detection method according to claim 1, wherein The method further includes the following steps: Obtain a preset set of ambient temperature values; For each ambient temperature value in the preset set of ambient temperature values, respectively determine the health state of the battery at each ambient temperature value; When the health states of the battery at all ambient temperature values are normal, determine that the overall health state of the battery is normal, otherwise determine that the overall health state of the battery is abnormal.

3. The battery health state detection method according to claim 1, characterized in that After determining that the health state of the battery at the target ambient temperature value is normal, otherwise determining that the health state of the battery is abnormal, the method further includes the following steps: Calculate the actual area between the first peak and the second peak, and the actual area between the second peak and the third peak at the target ambient temperature; According to the target ambient temperature value, obtain the area threshold range between the first peak and the second peak, and the area threshold range between the second peak and the third peak; Judge whether the actual areas are respectively within the corresponding area threshold ranges. If the actual areas are within the corresponding threshold ranges, determine that the area criterion result at the target ambient temperature value is normal, otherwise determine that the area criterion result is abnormal; According to the area criterion result, evaluate the health level of the battery at the target ambient temperature value and record the evaluation result.

4. The method for detecting the state of health of a battery according to claim 1, wherein Before obtaining the battery charging current-voltage curve at the target ambient temperature value, the method further includes the following steps: Periodically obtain the instantaneous current values of battery charging and discharging at the target ambient temperature value; Judge whether the instantaneous current values are within a preset normal range; If the instantaneous current values exceed the normal range, determine the current adjustment factor corresponding to the battery according to the target ambient temperature value; According to the current adjustment factor and the instantaneous current values, calculate the calibrated actual instantaneous current values.

5. The battery health state detection method according to claim 1, wherein The method further includes the following steps: Obtain the rated battery capacity corresponding to the target ambient temperature value; Calculate the capacity loss rate between the actual charging capacity obtained based on the capacity increment curve and the rated battery capacity; Predict the remaining cycle life of the battery according to the capacity loss rate.

6. The method for detecting the battery health state according to claim 5, wherein After predicting the remaining cycle life of the battery according to the capacity loss rate, the method further includes the following steps: Determine whether the remaining cycle life is less than a preset critical remaining cycle life; If the remaining cycle life is less than the preset critical remaining cycle life, determine that the battery has reached the end of its service life and issue a prompt to replace the battery with a new one.

7. The method for detecting the battery health state according to claim 5, wherein Predict the remaining cycle life N of the battery according to the capacity loss rate, where N is the remaining cycle life, Q is the capacity loss rate during cycling, and a, b, and c are fitting coefficients, and N = a*e^(b*(1 - Q)) + c.

8. A battery health state detection system, characterized in that, Include: A charging curve acquisition module for obtaining the battery charging current-voltage curve at the target ambient temperature value; An incremental capacity curve acquisition module for obtaining the capacity increment curve of battery charging at the target ambient temperature value based on the battery charging current-voltage curve by using incremental capacity analysis, where the capacity increment curve includes a first peak, a second peak, and a third peak; A numerical value acquisition module for determining the potential values and height values of the first peak, the second peak, and the third peak corresponding to the target ambient temperature value; A potential difference range acquisition module for obtaining the potential difference threshold range between the first peak and the second peak, the potential difference threshold range between the second peak and the third peak, the height difference threshold range between the first peak and the second peak, and the height difference threshold range between the second peak and the third peak according to the target ambient temperature value; An actual difference acquisition module for calculating the actual potential difference between the first peak and the second peak, the actual potential difference between the second peak and the third peak, the actual height difference between the first peak and the second peak, and the actual height difference between the second peak and the third peak at the target ambient temperature value; A health state judgment module for judging whether the actual potential difference is within the corresponding potential difference threshold range respectively, and judging whether the actual height difference is within the corresponding height difference threshold range. If both the actual potential difference and the actual height difference are within the corresponding threshold ranges, determine that the health state of the battery at the target ambient temperature value is normal, otherwise determine that the health state of the battery is abnormal.

9. An electronic device, characterized in that, Include a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the battery health state detection method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the battery health state detection method according to any one of claims 1-7.

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