Battery health state estimation method and device, electronic equipment and storage medium

Abstract

The invention relates to a battery health state estimation method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring a plurality of charging and discharging total capacities of a to-be-estimated battery under a preset condition, a state-of-charge difference value corresponding to each charging and discharging total capacity and a current battery cell cycle index of the to-be-estimated battery; obtaining a first health state of the to-be-estimated battery according to the plurality of charge-discharge total capacities and the charge state difference value corresponding to each charge-discharge total capacity, and obtaining a second health state of the to-be-estimated battery according to the current cell cycle index; and weighting according to the first health state and the second health state to obtain a final health state of the to-be-estimated battery. Therefore, weighted calculation is carried out on the health states of the to-be-estimated battery in different scenes to obtain the final health state, the problems of SOH value deviation caused by insufficient acquisition precision of a current sensor, insufficient SOH estimation adaptability in different use scenes and the like in related technologies are solved, and the precision and reliability of SOH estimation of the battery are improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly relates to a method, device, electronic device and storage medium for estimating the state of health of a battery. Background Art

[0002] With the rapid development of new energy, the market share of new energy vehicles has gradually increased. As an important component of new energy batteries, power batteries are essential for inspection, maintenance and repair; therefore, whether the state of health (SOH) of power batteries can be accurately evaluated has become a key issue. Since power batteries are large in volume and weight and are not easy to disassemble, this problem can be solved by online estimating the SOH of power batteries through a battery management system (BMS).

[0003] In related technologies, generally, signals such as the voltage, temperature, and current of the battery are collected in real time by the BMS, and the SOH value is estimated based on the driving habits and usage scenarios of the driver according to the collected battery data.

[0004] However, in related technologies, there is a situation where the acquisition accuracy of the current sensor is insufficient, resulting in a large deviation in the SOH value; at the same time, the requirements for real-time performance and accuracy cannot be met, which urgently needs to be solved. Summary of the Invention

[0005] The present application provides a method, device, electronic device and storage medium for estimating the state of health of a battery to solve problems such as the deviation of the SOH value caused by insufficient acquisition accuracy of the current sensor in related technologies and the insufficient adaptability of SOH estimation in different usage scenarios, and improve the accuracy and reliability of battery SOH estimation.

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

[0007] Obtain a plurality of total charge-discharge capacities of the battery to be estimated under preset conditions, the state of charge difference corresponding to each total charge-discharge capacity, and the current cell cycle number of the battery to be estimated;

[0008] Obtain the first state of health of the battery to be estimated according to the plurality of total charge-discharge capacities and the state of charge difference corresponding to each total charge-discharge capacity, and obtain the second state of health of the battery to be estimated according to the current cell cycle number;

[0009] Obtain the final state of health of the battery to be estimated by weighting the first state of health and the second state of health.

[0010] Optionally, obtaining a plurality of total charge and discharge capacities of the battery to be estimated under preset conditions and the state of charge difference corresponding to each total charge and discharge capacity includes:

[0011] Determine whether the battery to be estimated triggers a preset state of charge correction condition;

[0012] If the battery to be estimated triggers the preset state of charge correction condition, record the corrected first state of charge, and determine whether the battery to be estimated triggers the preset state of charge correction condition again;

[0013] If the battery to be estimated triggers the preset state of charge correction condition again, record the corrected second state of charge, and accumulate the total charge and discharge capacity from the first time the preset state of charge correction condition is triggered to the time when the state of charge correction condition of the battery is triggered again;

[0014] Obtain the state of charge difference corresponding to the total charge and discharge capacity according to the difference between the corrected second state of charge and the corrected first state of charge, and repeat the step of determining whether the battery to be estimated triggers the preset state of charge correction condition again until a preset end condition is met, to obtain the plurality of total charge and discharge capacities and the state of charge difference corresponding to each total charge and discharge capacity.

[0015] Optionally, obtaining the first health state of the battery to be estimated according to the plurality of total charge and discharge capacities and the state of charge difference corresponding to each total charge and discharge capacity includes:

[0016] Obtain the rated capacity of the battery to be estimated;

[0017] Calculate the ratio of each total charge and discharge capacity to the state of charge difference corresponding to each total charge and discharge capacity to obtain a plurality of ratios, and calculate the ratio of each ratio to the rated capacity to obtain a plurality of sub-health states;

[0018] Exclude the maximum sub-health state and the minimum sub-health state from the plurality of sub-health states to obtain a plurality of remaining sub-health states, and determine the coefficient corresponding to each remaining sub-health state. Weight the plurality of remaining sub-health states and the coefficients corresponding to each remaining sub-health state to obtain the first health state of the battery to be estimated.

[0019] Optionally, after calculating the ratio of each ratio to the rated capacity to obtain the plurality of sub-health states, it further includes:

[0020] Determine the coefficient corresponding to each sub-health state;

[0021] Weight the plurality of remaining sub-health states and the coefficients corresponding to each sub-health state to obtain the first health state of the battery to be estimated.

[0022] Optionally, obtaining the second health state of the battery to be estimated according to the current number of cell cycles includes:

[0023] Obtaining a comparison relation table of the cell capacity attenuation ratio and the number of cell cycles of the battery to be estimated;

[0024] Based on the comparison relation table, determining the cell capacity attenuation ratio of the battery to be estimated according to the current number of cell cycles, and obtaining the second health state of the battery to be estimated according to the cell capacity attenuation ratio of the battery to be estimated.

[0025] Optionally, obtaining the final health state of the battery to be estimated by weighting the first health state and the second health state includes:

[0026] Obtaining the cumulative discharge capacity from the corresponding moment when the first health state is calculated to the current moment;

[0027] Based on a preset weight calculation formula, determining a first weighting coefficient of the first health state according to the cumulative discharge capacity and the rated capacity of the battery to be estimated;

[0028] Obtaining a second weighting coefficient of the second health state according to the difference between a preset threshold and the first weighting coefficient;

[0029] Calculating a first product of the first health state and the first weighting coefficient, calculating a second product of the second health state and the second weighting coefficient, and obtaining the final health state according to the sum of the first product and the second product.

[0030] An embodiment of the second aspect of the present application provides a device for estimating the health state of a battery, including:

[0031] An acquisition module, configured to acquire a plurality of total charge-discharge capacities of the battery to be estimated under preset conditions, the state-of-charge difference corresponding to each total charge-discharge capacity, and the current number of cell cycles of the battery to be estimated;

[0032] A first determination module, configured to obtain the first health state of the battery to be estimated according to the plurality of total charge-discharge capacities and the state-of-charge difference corresponding to each total charge-discharge capacity, and obtain the second health state of the battery to be estimated according to the current number of cell cycles;

[0033] A second determination module, configured to obtain the final health state of the battery to be estimated by weighting the first health state and the second health state.

[0034] Optionally, the acquisition module is specifically configured to:

[0035] Determine whether the battery to be estimated triggers a preset state of charge correction condition;

[0036] If the battery to be estimated triggers the preset state of charge correction condition, record the corrected first state of charge, and determine whether the battery to be estimated triggers the preset state of charge correction condition again;

[0037] If the battery to be estimated triggers the preset state of charge correction condition again, record the corrected second state of charge, and accumulate the total charge-discharge capacity from triggering the preset state of charge correction condition to triggering the state of charge correction condition of the battery again;

[0038] Obtain the state of charge difference corresponding to the total charge-discharge capacity according to the difference between the corrected second state of charge and the corrected first state of charge, and repeat the step of determining whether the battery to be estimated triggers the preset state of charge correction condition again until a preset end condition is met, to obtain the multiple total charge-discharge capacities and the state of charge differences corresponding to each total charge-discharge capacity.

[0039] Optionally, the first determination module is specifically configured to:

[0040] Obtain the rated capacity of the battery to be estimated;

[0041] Calculate the ratio of each total charge-discharge capacity to the state of charge difference corresponding to each total charge-discharge capacity to obtain multiple ratios, and calculate the ratio of each ratio to the rated capacity to obtain multiple sub-health states;

[0042] Exclude the maximum sub-health state and the minimum sub-health state from the multiple sub-health states to obtain multiple remaining sub-health states, and determine the coefficient corresponding to each remaining sub-health state, and obtain the first health state of the battery to be estimated by weighting the multiple remaining sub-health states and the coefficient corresponding to each remaining sub-health state.

[0043] Optionally, the first determination module is further configured to:

[0044] Determine the coefficient corresponding to each sub-health state;

[0045] Obtain the first health state of the battery to be estimated by weighting the multiple remaining sub-health states and the coefficient corresponding to each sub-health state.

[0046] Optionally, the first determination module is specifically configured to:

[0047] Obtain the comparison relationship table of the cell capacity attenuation ratio and the cell cycle number of the battery to be estimated;

[0048] Based on the comparison relation table, determine the cell capacity attenuation ratio of the battery to be estimated according to the current cell cycle number of the battery to be estimated, and obtain the second health state of the battery to be estimated according to the cell capacity attenuation ratio of the battery to be estimated.

[0049] Optionally, the second determination module is specifically configured to:

[0050] Obtain the cumulative discharge capacity from the corresponding moment when the first health state is calculated to the current moment;

[0051] Based on a preset weight calculation formula, determine the first weighting coefficient of the first health state according to the cumulative discharge capacity and the rated capacity of the battery to be estimated;

[0052] Obtain the second weighting coefficient of the second health state according to the difference between the preset threshold and the first weighting coefficient;

[0053] Calculate the first product of the first health state and the first weighting coefficient, calculate the second product of the second health state and the second weighting coefficient, and obtain the final health state according to the sum of the first product and the second product.

[0054] An embodiment of the third aspect of the present application provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and the instructions are configured to execute the method for estimating the health state of the battery as described in the above embodiment.

[0055] An embodiment of the fourth aspect of the present application provides a computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to implement the method for estimating the health state of the battery as described in the above embodiment.

[0056] Thus, after obtaining the total charge-discharge capacities of the battery to be estimated under preset conditions, the state-of-charge difference corresponding to each total charge-discharge capacity, and the current cell cycle number of the battery to be estimated, the first health state of the battery to be estimated is obtained according to the total charge-discharge capacities and the state-of-charge difference corresponding to each total charge-discharge capacity, the second health state of the battery to be estimated is obtained according to the current cell cycle number, and then the final health state of the battery to be estimated is obtained by weighting the first health state and the second health state. Thus, the final health state is obtained by weighted calculation of the health state of the battery to be estimated in different scenarios, solving the problems in the related art such as the deviation of the SOH value caused by the insufficient acquisition accuracy of the current sensor and the insufficient adaptability of the SOH estimation in different usage scenarios, and improving the accuracy and reliability of the battery SOH estimation.

[0057] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Description of the Drawings

[0058] The above-mentioned and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description of embodiments in conjunction with the drawings, where:

[0059] Figure 1 It is a flowchart of a method for estimating the state of health of a battery provided according to an embodiment of the present application;

[0060] Figure 2 It is a flowchart of a two-point method for a method for estimating the state of health of a battery provided according to an embodiment of the present application;

[0061] Figure 3 It is a flowchart of a cycle life method for a method for estimating the state of health of a battery provided according to an embodiment of the present application;

[0062] Figure 4 It is a schematic diagram of an SOH weighted fusion model for a method for estimating the state of health of a battery provided according to an embodiment of the present application;

[0063] Figure 5 It is a block schematic diagram of a device for estimating the state of health of a battery provided according to an embodiment of the present application;

[0064] Figure 6 It is a schematic structural diagram of an electronic device provided according to an embodiment of the present application. Detailed Embodiments

[0065] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the drawings, where 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 by referring to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0066] Before introducing the method for estimating the state of health of the battery according to the embodiments of the present application, a method for estimating the state of health of the battery in the related art will be briefly introduced.

[0067] Specifically, in the related art, a method for estimating the state of health (SOH) value based on the change in the state of charge of the battery, the actual charge capacity of the battery, and the rated capacity during the parking charging process of the battery is disclosed. The invention provides a method, device, vehicle, and medium for evaluating the SOH of a hybrid power battery system. The SOH of the hybrid power battery system within a preset period is obtained according to the change in the state of charge of the battery, the actual charge capacity of the battery, and the rated capacity of the hybrid power battery system for each group of parking charging processes.

[0068] Furthermore, a battery SOH estimation method, system, device, and storage medium are disclosed in the related art. The method includes: obtaining the previous cycle SOH of the battery, the current cumulative charge capacity, the current charge cumulative capacity array, the state of charge (SOC) of the battery, the cumulative ampere-hour integral, and the nominal capacity; determining the detected SOH of the battery according to the current cumulative charge capacity and the current charge cumulative capacity array; determining the corrected SOH of the battery according to the current cumulative charge capacity, the cumulative ampere-hour integral, the nominal capacity, and the state of charge of the battery; and determining the target estimated value of the battery SOH according to the previous cycle SOH, the detected SOH, and the corrected SOH. By adaptively detecting the SOH of the battery and correcting the battery based on the current aging state of the battery, the SOH estimation result is adaptively corrected according to the state of the battery to ensure the stability of the target estimated value of the SOH.

[0069] However, in the related art, the acquisition accuracy of the current sensor is insufficient, resulting in a large deviation in the SOH value. In the embodiments of the present application, data is screened, and the data in the interval with a large difference in the state of charge of the battery is used to calculate the SOH, reducing the influence brought by the acquisition accuracy of the current sensor. Through multiple algorithms, the most accurate estimation method is adopted according to different scenarios.

[0070] Based on the above problems, the present application proposes a method for estimating the health state of a battery. In this method, a plurality of total charge-discharge capacities of the battery to be estimated under preset conditions, the state of charge difference corresponding to each total charge-discharge capacity, and the current cell cycle number of the battery to be estimated are obtained; the first health state of the battery to be estimated is obtained according to the plurality of total charge-discharge capacities and the state of charge difference corresponding to each total charge-discharge capacity, and the second health state of the battery to be estimated is obtained according to the current cell cycle number; the final health state of the battery to be estimated is obtained by weighting the first health state and the second health state. Thus, the final health state is obtained by weighted calculation of the health state of the battery to be estimated in different scenarios, solving the problems in the related art such as the deviation of the SOH value caused by the insufficient acquisition accuracy of the current sensor and the insufficient adaptability of the SOH estimation in different usage scenarios, and improving the accuracy and reliability of the battery SOH estimation.

[0071] Specifically, Figure 1 is a flowchart of a method for estimating the health state of a battery according to an embodiment of the present application. As Figure 1 shown, the method for estimating the health state of the battery includes the following steps:

[0072] In step S101, a plurality of total charge-discharge capacities of the battery to be estimated under preset conditions, the state of charge difference corresponding to each total charge-discharge capacity, and the current cell cycle number of the battery to be estimated are obtained.

[0073] Optionally, in some embodiments, obtaining a plurality of total charge-discharge capacities of the battery to be estimated under preset conditions and the state-of-charge difference corresponding to each total charge-discharge capacity includes: determining whether the battery to be estimated triggers a preset state-of-charge correction condition; if the battery to be estimated triggers the preset state-of-charge correction condition, recording the corrected first state of charge, and determining whether the battery to be estimated triggers the preset state-of-charge correction condition again; if the battery to be estimated triggers the preset state-of-charge correction condition again, recording the corrected second state of charge, and accumulating the total charge-discharge capacity of the first charge-discharge until the battery's state-of-charge correction condition is triggered again; obtaining the state-of-charge difference corresponding to the first total charge-discharge capacity according to the difference between the corrected second state of charge and the corrected first state of charge, and repeating the step of determining whether the battery to be estimated triggers the preset state-of-charge correction condition again until a preset end condition is met, obtaining a plurality of total charge-discharge capacities and the state-of-charge difference corresponding to each total charge-discharge capacity.

[0074] Among them, the state-of-charge difference (ΔSOC) refers to the change in the state of charge of the battery between two state-of-charge measurements. The current cell cycle count refers to the number of charge-discharge cycles that the battery has completed from the first use to the current time. The preset state-of-charge correction condition refers to a series of trigger conditions set in the battery management system to ensure the accuracy of the state of charge. When these conditions are met, the BMS will perform the state-of-charge correction operation of the battery to reduce the state-of-charge error of the battery caused by factors such as current sensor accuracy and temperature change. For example, the preset state-of-charge correction condition can be that the battery to be estimated meets the condition of standing still for a set time and the monomer voltage is within the set range.

[0075] It can be understood that by obtaining the relevant data of the battery to be estimated under preset conditions, analyzing information such as the capacity attenuation trend and health status of the battery, it provides a basis for battery maintenance and replacement; triggering the state-of-charge correction condition multiple times to capture the state-of-charge changes of the battery at different usage stages, and more comprehensively understand the performance changes of the battery; calculating the difference in the state of charge after two corrections to quantify the charge-discharge behavior of the battery during the two corrections, providing key data for subsequent calculations; the embodiments of the present application can dynamically adapt to various complex working conditions that the battery may encounter during actual use (such as different temperatures, different charge-discharge rates, etc.), ensuring the accuracy and reliability of the state-of-charge estimation of the battery; by repeating the above steps and accumulating data of multiple charge-discharge cycles, it helps to identify the long-term trends and patterns of battery performance and more accurately estimate the SOH.

[0076] In step S102, the first health state of the battery to be estimated is obtained according to a plurality of total charge-discharge capacities and the state-of-charge difference corresponding to each total charge-discharge capacity, and the second health state of the battery to be estimated is obtained according to the current cell cycle count.

[0077] Optionally, in some embodiments, obtaining a first state of health of a battery to be estimated based on a plurality of total charge-discharge capacities and the difference in state of charge corresponding to each total charge-discharge capacity includes: obtaining the rated capacity of the battery to be estimated; calculating the ratio of each total charge-discharge capacity to the difference in state of charge corresponding to each total charge-discharge capacity to obtain a plurality of ratios, and calculating the ratio of each ratio to the rated capacity to obtain a plurality of sub-states of health; excluding the maximum sub-state of health and the minimum sub-state of health from the plurality of sub-states of health to obtain a plurality of remaining sub-states of health, and determining the coefficient corresponding to each remaining sub-state of health, and obtaining the first state of health of the battery to be estimated by weighting the plurality of remaining sub-states of health and the coefficient corresponding to each remaining sub-state of health.

[0078] Among them, the first state of health (SOH1) refers to the state of health of the battery calculated by the two-point method. SOH1 is obtained by triggering the state of charge correction condition of the battery multiple times, recording the state of charge values of the corrected battery, and accumulating the total charge-discharge capacity (ΔAH) during this period, and then calculated by a specific formula. The second state of health (SOH2) refers to the state of health of the battery calculated by the cycle life method. SOH2 is estimated by accumulating the total discharge capacity within the life cycle of the battery pack and the rated capacity (CAP) of the battery pack, and combining the control relationship table of the capacity attenuation ratio and the number of cycles of the battery cell. The maximum sub-state of health and the minimum sub-state of health refer to the maximum value and the minimum value selected from the sub-state of health values obtained by multiple calculations when calculating SOH1.

[0079] It can be understood that the embodiments of the present application can more accurately reflect the performance changes of the battery during the charge-discharge process by calculating the ratio of the total capacity of each charge-discharge cycle to the difference in state of charge corresponding thereto and considering the rated capacity, and can comprehensively evaluate the state of health of the battery more than a single index; excluding the maximum sub-state of health and the minimum sub-state of health reduces the influence of abnormal data or extreme situations on the final result, thereby improving the stability and reliability of the evaluation result; by weighting a plurality of remaining sub-states of health, it more truly reflects the overall health status of the battery during actual use. The embodiments of the present application provide an effective method for accurately evaluating the state of health of the battery by comprehensively considering the charge-discharge data, rated capacity of the battery, and the weighted results of a plurality of sub-states of health, which helps to improve the reliability and accuracy of the evaluation result, and provides strong support for battery maintenance, management, and energy optimization.

[0080] As a specific embodiment, as Figure 2 shown, Figure 2 is a flowchart of a method for obtaining the first state of health provided by an embodiment of the present application. The method for obtaining the first state of health (i.e., the two-point method) includes the following steps:

[0081] 1. When the static state reaches the set time and the monomer voltage is within the set range, trigger the correction of the state of charge of the battery, record the state of charge value of the corrected battery, and denote it as SOC1. When triggering the correction again, record SOC2, and calculate the difference ΔSOC between the two states of charge of the battery.

[0082] 2. Starting from the first time the state of charge of the battery is triggered for correction, accumulate the total charge and discharge capacity calculated this time until the second time the state of charge of the battery is triggered for correction ends ΔAH (i.e., the difference in charge and discharge capacity). Considering the current accuracy, if the accumulated total capacity value this time exceeds m times (m is a coefficient less than 1) the rated capacity CAP (the rated capacity value CAP given by the battery manufacturer), then it is considered that the calculation this time is valid. It should be understood that the value of m is obtained through multiple experiments, which should not only ensure the calculation accuracy but also satisfy multiple triggers; because ΔAH is the integral of current over time and there is a certain error in current accuracy, when the time length is long enough, the influence of current accuracy on ΔAH is smaller, the longer the time, the closer ΔAH is to the rated capacity, that is, the larger the value of m, the more accurate ΔAH is, and the more accurate the calculated ΔSOH is; because few people use electricity until it is completely out of power and then recharge, so the larger the value of m, the fewer the number of times to trigger the calculation of ΔAH.

[0083] If the accumulated total capacity value this time is less than m times the rated capacity, it is considered that the influence of current accuracy has a greater impact on the estimated ΔSOH, discard the data this time, and clear the accumulated total charge and discharge capacity this time. Start accumulating again, so that the probability of triggering the algorithm effectively can be increased.

[0084] ΔSOH = ΔAH / ΔSOC / CAP (Formula 1)

[0085] ΔSOH represents the SOH value calculated by the two-point method, labeled as SOHnn.

[0086] Due to the current accuracy and the error of the accumulated total capacity, the ΔSOH value calculated by the two-point method will cause a deviation in the SOH value. Considering this situation, it is necessary to accumulate the ΔSOH values of the two-point method (n + 2 times), remove the largest and the smallest ΔSOH values, and the remaining n ΔSOH values are added according to the coefficient to obtain the final SOH1 value of the two-point method (i.e., the first health state).

[0087] SOH1 = SOH n1 *J 1 +SOH n2 *J 2 + … +SOH nn *J n (Formula 2)

[0088] J1 + J 2 + … + J n =1 (Formula 3)

[0089] Among them, Jn is the coefficient of SOHnn. Jn calculates the ratio based on the difference Tnn between the time calculated from SOHnn and the current time.

[0090] J x =(T 1 +T 2 +…+T n -T x ) / (T 1 +T 2 +…+T n ) / (n - 1) (Formula 4)

[0091] X is any value point between 1 and n.

[0092] When calculating beyond the (n + 2)-th ΔSOH value according to the two-point method, it is necessary to remove one maximum and one minimum ΔSOH value from the (n + 2) recent ΔSOH values obtained by the two-point method. For the remaining n ΔSOH values, calculate the SOH1 value based on the difference from the current time.

[0093] For example, if n is 4, when obtaining and calculating 6 ΔSOH (1 - 6), calculate SOH1 according to Formula 4 for the remaining 4 ΔSOH after removing the maximum and minimum among the 6; when the 7th ΔSOH appears, take the 6 ΔSOH from 2 - 7, remove the maximum and minimum among them, and calculate SOH1 according to Formula 4. That is, the value of SOH1 is updated as the obtained ΔSOH rolls.

[0094] Optionally, in some embodiments, obtaining the second state of health of the battery to be estimated according to the current number of cell cycles includes: obtaining a comparison table of the cell capacity attenuation ratio and the number of cell cycles of the battery to be estimated; based on the comparison table, determining the cell capacity attenuation ratio of the battery to be estimated according to the current number of cell cycles, and obtaining the second state of health of the battery to be estimated according to the cell capacity attenuation ratio of the battery to be estimated.

[0095] Among them, the cell capacity attenuation ratio refers to the degree to which the battery capacity gradually decreases during use due to factors such as aging and cyclic charge and discharge, and is the ratio of the current actual capacity of the battery to the initial rated capacity.

[0096] It can be understood that through the comparison relation table, the performance of the battery in subsequent use can be predicted more accurately; according to the estimation result of the battery health state, a more reasonable battery management strategy can be formulated. By predicting and evaluating the battery health state in a timely manner, preventive measures can be taken before the battery has problems, which helps to reduce the maintenance cost of the battery and avoid unnecessary replacement or repair costs; in the battery system, by monitoring and evaluating the health state of each battery, the performance of the entire system can be optimized.

[0097] As a specific embodiment, such as Figure 3 shown Figure 3 is a flowchart of a second method for obtaining the health state provided by an embodiment of the present application. The second method for obtaining the health state (i.e., the cycle life method) includes the following steps:

[0098] According to the cumulative current integral of the battery pack from the first wake-up to the current time, which is called the total discharge capacity AHDischg, and the rated capacity CAP of the battery pack, the number of cycles NUMchg that the current battery pack has been used can be obtained. The formula is as follows:

[0099] NUMchg = AHDischg / CAP (Formula 5)

[0100] Considering the consistency of all the battery cells in the battery pack, ideally, the capacity attenuation of the battery pack is the same as that of the battery cells. The cycle life method is to evaluate the approximate SOH value of the battery pack, denoted as SOH2, by looking up the table according to the comparison relation table between the capacity attenuation ratio and the number of cycles of the battery cells of the battery.

[0101] In step S103, the final health state of the battery to be estimated is obtained by weighting the first health state and the second health state.

[0102] Optionally, in some embodiments, obtaining the final health state of the battery to be estimated by weighting the first health state and the second health state includes: obtaining the cumulative discharge capacity from the corresponding moment when the first health state is calculated to the current moment; based on a preset weight calculation formula, determining the first weighting coefficient of the first health state according to the cumulative discharge capacity and the rated capacity of the battery to be estimated; obtaining the second weighting coefficient of the second health state according to the difference between the preset threshold and the first weighting coefficient; calculating the first product of the first health state and the first weighting coefficient, and calculating the second product of the second health state and the second weighting coefficient, and obtaining the final health state according to the sum of the first product and the second product.

[0103] Among them, the cumulative discharge capacity refers to the electric quantity cumulatively released by the battery from the last time when the effective SOH1 was calculated to the current time, and is used to adjust the weights of the two-point method and the cycle life method in the calculation of the final state of health (SOH). The preset weight calculation formula is used to determine the weights of SOH1 and SOH2 in the SOH calculation. This formula adjusts the weight of the two-point method according to the cumulative discharge capacity and the rated capacity of the battery, so as to ensure the accuracy of the SOH calculation.

[0104] It can be understood that accurate state of health assessment helps to formulate more reasonable battery management strategies, such as charging strategies, maintenance plans or replacement times; through timely state of health monitoring and assessment, potential problems of the battery can be detected in time, and preventive measures can be taken to extend the service life of the battery; it helps users better understand the battery performance and reasonably arrange the usage plan, thereby improving the user experience.

[0105] As a specific embodiment, such as Figure 4 shown Figure 4 is a schematic diagram of the SOH weighted fusion model of a method for estimating the state of health of a battery provided by an embodiment of the present application, that is, a method for obtaining the final state of health. The SOH weighted fusion model of the method for estimating the state of health of the battery includes:

[0106] The SOH value of the battery pack is obtained by weighting the first state of health and the second state of health obtained by the cycle life method and the two-point method. The calculation trigger condition of the two-point method is that the state of charge of the battery satisfies the correction condition to obtain a considered accurate state of charge value of the battery, and ΔSOH is calculated. When n + 2 ΔSOH are satisfied, an effective SOH1 can be calculated. Considering that the calculation trigger condition of the two-point method is not easy to meet, before the two-point method calculates SOH1, the SOH value mainly relies on the SOH2 value calculated by the cycle life method. After the two-point method calculates SOH1, since the two-point method has higher accuracy than the cycle life method, according to multiple experimental data, the weight of the two-point method is larger, which is Y%. The cumulative discharge AH value between the current time and the SOH1 value of the two-point method calculated last time is recorded as AHDiff. If the AHDiff value is larger, it is considered that the credibility of the final value calculated by the two-point method will decrease.

[0107] The formula for calculating the weight K of the two-point method is as follows:

[0108] K = Y% - (AHDiff / CAP) * Z% (Formula 6)

[0109] Among them, both Y and Z are constants, and Y and Z can be obtained by fitting through the following method:

[0110] Specifically, during testing, the true SOH value at time t1 is obtained. According to the above two-point method and the cycle count method, SOH1 and SOH2 are calculated respectively. K1 is obtained by using SOH_true = SOH1*K1 + SOH2*(1 - K1). The current AHDiff is 0. At the moment t2 when SOH1 is calculated in the next untriggered condition, the true SOH value ’ is obtained and SOH2’ is calculated. The cumulative discharge value AHDiff between t1 and t2 is calculated. K2 is obtained by SOH_true ’ = SOH1*K2 + SOH2’*(1 - K2). Multiple groups of test data are obtained in sequence. With AHDiff as the abscissa and K as the ordinate, formula 6 is obtained by fitting.

[0111] According to multiple experimental data, before the SOH1 value calculated by the new two-point method is triggered, the proportion of SOH1 calculated by the two-point method will gradually decrease with the battery's discharged electricity. After passing through multiple discrete points, the optimal straight line is taken to obtain Y and Z.

[0112] It should be noted that when calculating SOH1 in the embodiments of the present application, if n + 2 points are not collected for ΔSOH, the SOH1 value is unavailable. At this time, the embodiments of the present application can obtain the final health state of the battery to be estimated through formula 7:

[0113] SOH = SOH2 (formula 7)

[0114] When ΔSOH collects more than or equal to n + 2 points, the effective value of SOH1 can be calculated. At this time:

[0115] SOH = SOH1*K + SOH2(1 - K) (formula 8)

[0116] Thus, through data screening, the data in the interval with a large difference in the state of charge of the battery is used to calculate SOH, reducing the influence caused by the acquisition accuracy of the current sensor; after multiple calculations, the maximum and minimum are removed, and the average value of the remaining data is taken to reduce the influence of a single calculation error on the final SOH value; considering various usage scenarios of customers, the method of calculating the SOH value through multiple algorithms includes the cycle life method and the two-point method (i.e., the method of obtaining the first health state and the method of obtaining the second health state); according to different scenarios, the actual SOH of the battery is estimated by the most accurate method. Before the two-point method calculates the final value, the cycle life method calculation method is used to estimate the SOH value; in the embodiments of the present application, data screening, excluding occasional abnormal data processing in the two-point method, and calculating the SOH value under different working conditions are used.

[0117] Furthermore, when calculating the first health state, the embodiments of the present application can also be calculated in the following manner.

[0118] Optionally, in some embodiments, after calculating the ratios of each ratio and the rated capacity to obtain multiple sub-healthy states, the method further includes: determining the corresponding coefficient of each sub-healthy state; and obtaining the first healthy state of the battery to be estimated by weighting based on the multiple remaining sub-healthy states and the corresponding coefficient of each sub-healthy state.

[0119] It can be understood that after calculating multiple sub-healthy states in the embodiments of the present application, without removing the maximum sub-healthy state and the minimum sub-healthy state, directly determine the corresponding coefficient of each sub-healthy state, and then perform weighted calculation of the first healthy state of the battery to be estimated based on the determined corresponding coefficient of each sub-healthy state. Compared with calculating the first healthy state of the battery to be estimated after removing the maximum sub-healthy state and the minimum sub-healthy state, the time is shorter. Those skilled in the art can arbitrarily select a method for calculating the first healthy state of the battery to be estimated according to the actual situation to meet different application requirements.

[0120] For example, if n is 4, it is necessary to obtain and calculate 4 ΔSOHs, and calculate SOH1 according to Formula 4; when the 5th ΔSOH appears, take the 4 ΔSOHs from 2 to 5 and calculate SOH1 according to Formula 4, that is, the value of SOH1 is updated as the obtained ΔSOHs roll.

[0121] According to the method for estimating the healthy state of a battery proposed in the embodiments of the present application, obtain multiple charge-discharge total capacities of the battery to be estimated under preset conditions, the state-of-charge difference corresponding to each charge-discharge total capacity, and the current cell cycle number of the battery to be estimated; obtain the first healthy state of the battery to be estimated according to the multiple charge-discharge total capacities and the state-of-charge difference corresponding to each charge-discharge total capacity, and obtain the second healthy state of the battery to be estimated according to the current cell cycle number; obtain the final healthy state of the battery to be estimated by weighting the first healthy state and the second healthy state. Thereby, the weighted calculation of the healthy state of the battery to be estimated in different scenarios obtains the final healthy state, which solves the problems in the related art such as the deviation of the SOH value caused by the insufficient acquisition accuracy of the current sensor and the insufficient adaptability of the SOH estimation in different usage scenarios, and improves the accuracy and reliability of the battery SOH estimation.

[0122] Next, a device for estimating the healthy state of a battery according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0123] Figure 5 It is a block diagram of a device for estimating the healthy state of a battery according to an embodiment of the present application.

[0124] As Figure 5 shown, the device 10 for estimating the healthy state of a battery includes: an acquisition module 100, a first determination module 200, and a second determination module 300.

[0125] Among them, the acquisition module 100 is configured to acquire a plurality of total charge-discharge capacities of the battery to be estimated under preset conditions, the state-of-charge difference corresponding to each total charge-discharge capacity, and the current cell cycle number of the battery to be estimated;

[0126] The first determination module 200 is configured to obtain the first health state of the battery to be estimated according to the plurality of total charge-discharge capacities and the state-of-charge difference corresponding to each total charge-discharge capacity, and obtain the second health state of the battery to be estimated according to the current cell cycle number;

[0127] The second determination module 300 is configured to obtain the final health state of the battery to be estimated by weighting the first health state and the second health state.

[0128] Optionally, the acquisition module 100 is specifically configured to: determine whether the battery to be estimated triggers a preset state-of-charge correction condition; if the battery to be estimated triggers the preset state-of-charge correction condition, record the corrected first state of charge, and determine whether the battery to be estimated triggers the preset state-of-charge correction condition again; if the battery to be estimated triggers the preset state-of-charge correction condition again, record the corrected second state of charge, and accumulate the total charge-discharge capacity from when the preset state-of-charge correction condition is triggered to when the state-of-charge correction condition of the battery is triggered again; obtain the state-of-charge difference corresponding to the first total charge-discharge capacity according to the difference between the corrected second state of charge and the corrected first state of charge, and repeat the step of determining whether the battery to be estimated triggers the preset state-of-charge correction condition again until a preset end condition is met, to obtain a plurality of total charge-discharge capacities and the state-of-charge difference corresponding to each total charge-discharge capacity.

[0129] Optionally, the first determination module 200 is specifically configured to: obtain the rated capacity of the battery to be estimated; calculate the ratio of each total charge-discharge capacity to the state-of-charge difference corresponding to each total charge-discharge capacity to obtain a plurality of ratios, and calculate the ratio of each ratio to the rated capacity to obtain a plurality of sub-health states; eliminate the maximum sub-health state and the minimum sub-health state from the plurality of sub-health states to obtain a plurality of remaining sub-health states, and determine the coefficient corresponding to each remaining sub-health state, and obtain the first health state of the battery to be estimated by weighting the plurality of remaining sub-health states and the coefficient corresponding to each remaining sub-health state.

[0130] Optionally, the first determination module 200 is further configured to: determine the coefficient corresponding to each sub-health state; and obtain the first health state of the battery to be estimated by weighting the plurality of remaining sub-health states and the coefficient corresponding to each sub-health state.

[0131] Optionally, the first determination module 200 is specifically configured to: obtain a comparison relationship table of the cell capacity attenuation ratio and the cell cycle number of the battery to be estimated; based on the comparison relationship table, determine the cell capacity attenuation ratio of the battery to be estimated according to the current cell cycle number, and obtain the second health state of the battery to be estimated according to the cell capacity attenuation ratio of the battery to be estimated.

[0132] Optionally, the second determination module 300 is specifically configured to: obtain the cumulative discharge capacity from the corresponding moment when the first health state is calculated to the current moment; based on a preset weight calculation formula, determine the first weighting coefficient of the first health state according to the cumulative discharge capacity and the rated capacity of the battery to be estimated; obtain the second weighting coefficient of the second health state according to the difference between the preset threshold and the first weighting coefficient; calculate the first product of the first health state and the first weighting coefficient, calculate the second product of the second health state and the second weighting coefficient, and obtain the final health state according to the sum of the first product and the second product.

[0133] It should be noted that the foregoing explanation of the embodiments of the battery health state estimation method also applies to the battery health state estimation device of this embodiment, and will not be elaborated here.

[0134] According to the battery health state estimation device provided by the embodiments of the present application, after obtaining multiple charge-discharge total capacities of the battery to be estimated under preset conditions, the state-of-charge difference corresponding to each charge-discharge total capacity, and the current cell cycle number of the battery to be estimated, the first health state of the battery to be estimated is obtained according to the multiple charge-discharge total capacities and the state-of-charge difference corresponding to each charge-discharge total capacity, the second health state of the battery to be estimated is obtained according to the current cell cycle number, and then the final health state of the battery to be estimated is obtained by weighting the first health state and the second health state. Thus, the final health state is obtained by weighted calculation of the health state of the battery to be estimated in different scenarios, solving the problems in the related art such as the deviation of the SOH value caused by insufficient acquisition accuracy of the current sensor and the insufficient adaptability of the SOH estimation in different usage scenarios, and improving the accuracy and reliability of the battery SOH estimation.

[0135] Figure 6 The structural schematic diagram of the electronic device provided by the embodiments of the present application. The electronic device may include:

[0136] A memory 601, a processor 602, and a computer program stored on the memory 601 and executable on the processor 602.

[0137] When the processor 602 executes the program, it implements the battery health state estimation method provided in the foregoing embodiments.

[0138] Further, the electronic device further includes:

[0139] A communication interface 603 for communication between the memory 601 and the processor 602.

[0140] A memory 601 for storing computer programs that can run on the processor 602.

[0141] The memory 601 may include a high-speed RAM memory and may also include non-volatile memory, such as at least one disk memory.

[0142] If the memory 601, the processor 602, and the communication interface 603 are implemented independently, the communication interface 603, the memory 601, and the processor 602 can be interconnected through a bus to complete communication with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus or one type of bus.

[0143] Optionally, in a specific implementation, if the memory 601, the processor 602, and the communication interface 603 are integrated on a chip, the memory 601, the processor 602, and the communication interface 603 can complete communication with each other through an internal interface.

[0144] The processor 602 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0145] The embodiments of the present application also provide a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the method for estimating the health state of a battery as described above is implemented.

[0146] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0147] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0148] Any process or method description shown in a flowchart or described in other ways herein can be understood to represent a module, segment, or portion of code including one or more N executable instructions for implementing a customized logical function or process. And the scope of the preferred embodiments of this application includes additional implementations, where the functions can be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art to which the embodiments of this application pertain.

[0149] It should be understood that each part of this application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one of the following well-known technologies in the art or a combination of them can be used: discrete logic circuits with logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits with suitable combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0150] Those of ordinary skill in the technical field of this application can understand that all or part of the steps carried by the method for implementing the above embodiments can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

Claims

1. A method for estimating the health status of a battery, characterized in that: The following steps are involved: Obtaining a plurality of total charge and discharge capacities of the battery to be estimated under preset conditions, a state of charge difference corresponding to each total charge and discharge capacity, and a current number of battery cell cycles of the battery to be estimated; Obtaining a first health state of the battery to be estimated according to the multiple charge and discharge total capacities and a difference in the state of charge corresponding to each of the charge and discharge total capacities, and obtaining a second health state of the battery to be estimated according to the current number of battery cell cycles; The final health state of the battery to be estimated is obtained by weighting the first health state and the second health state.

2. The method according to claim 1, characterized in that The step of obtaining a plurality of total charge and discharge capacities of the battery to be estimated under preset conditions and a state of charge difference corresponding to each total charge and discharge capacity includes: Determining whether the battery to be estimated triggers a preset state of charge correction condition; If the battery to be estimated triggers the preset state of charge correction condition, then record the corrected first state of charge, and determine whether the battery to be estimated triggers the preset state of charge correction condition again; If the battery to be estimated triggers the preset state of charge correction condition again, the corrected second state of charge is recorded, and the first total charge and discharge capacity from when the preset state of charge correction condition is triggered to when the state of charge correction condition of the battery is triggered again is accumulated; A state of charge difference corresponding to the first charge-discharge total capacity is obtained according to the difference between the corrected second state of charge and the corrected first state of charge, and the step of determining whether the battery to be estimated triggers the preset state of charge correction condition again is repeated until a preset termination condition is met, thereby obtaining the multiple charge-discharge total capacities and the state of charge difference corresponding to each charge-discharge total capacity.

3. The method according to claim 2, characterized in that The obtaining the first health state of the battery to be estimated according to the plurality of charge and discharge total capacities and the charge state difference corresponding to each of the charge and discharge total capacities includes: Obtaining the rated capacity of the battery to be estimated; Calculating the ratio of each total charge and discharge capacity to the charge state difference corresponding to each total charge and discharge capacity to obtain multiple ratios, and calculating the ratio of each ratio to the rated capacity to obtain multiple sub-health states; The maximum sub-health state and the minimum sub-health state are eliminated from the multiple sub-health states to obtain multiple remaining sub-health states, and a coefficient corresponding to each remaining sub-health state is determined. The first health state of the battery to be estimated is obtained by weighting the multiple remaining sub-health states and the coefficient corresponding to each remaining sub-health state.

4. The method according to claim 3, characterized in that After calculating each ratio and the ratio of the rated capacity to obtain the plurality of sub-health states, the method further includes: Determine the corresponding coefficient for each sub-health state; The first health state of the battery to be estimated is obtained by weighting the plurality of remaining health sub-states and the corresponding coefficient of each health sub-state.

5. The method according to claim 1, characterized in that The obtaining the second health state of the battery to be estimated according to the current battery cell cycle number includes: Obtaining a comparison relationship table between the cell capacity attenuation ratio and the cell cycle number of the battery to be estimated; Based on the comparison relationship table, the cell capacity attenuation ratio of the battery to be estimated is determined according to the current cell cycle number, and the second health state of the battery to be estimated is obtained according to the cell capacity attenuation ratio of the battery to be estimated.

6. The method according to claim 1, characterized in that The step of obtaining the final health state of the battery to be estimated by weighting the first health state and the second health state includes: Obtaining and calculating the cumulative discharge capacity from the corresponding moment of the first health state to the current moment; Based on a preset weight calculation formula, determining a first weighting coefficient of the first health state according to the accumulated discharge capacity and the rated capacity of the battery to be estimated; Obtaining a second weighting coefficient for the second health state according to a difference between a preset threshold and the first weighting coefficient; A first product of the first health state and the first weighting coefficient is calculated, and a second product of the second health state and the second weighting coefficient is calculated, and the final health state is obtained according to the sum of the first product and the second product.

7. A battery health status estimation device, characterized in that: include: An acquisition module, used to acquire a plurality of total charge and discharge capacities of a battery to be estimated under preset conditions, a state of charge difference corresponding to each total charge and discharge capacity, and a current number of battery cell cycles of the battery to be estimated; A first determination module, configured to obtain a first health state of the battery to be estimated according to the plurality of charge and discharge total capacities and a difference in the state of charge corresponding to each of the charge and discharge total capacities, and to obtain a second health state of the battery to be estimated according to the current number of battery cell cycles; The second determination module is used to obtain a final health state of the battery to be estimated by weighting the first health state and the second health state.

8. The device according to claim 7, characterized in that The first determining module is specifically configured to: Determining whether the battery to be estimated triggers a preset state of charge correction condition; If the battery to be estimated triggers the preset state of charge correction condition, then record the corrected first state of charge, and determine whether the battery to be estimated triggers the preset state of charge correction condition again; If the battery to be estimated triggers the preset state of charge correction condition again, the corrected second state of charge is recorded, and the first total charge and discharge capacity from when the preset state of charge correction condition is triggered to when the state of charge correction condition of the battery is triggered again is accumulated; A state of charge difference corresponding to the first charge-discharge total capacity is obtained according to the corrected second state of charge and the corrected first state of charge, and the step of determining whether the battery to be estimated triggers the preset state of charge correction condition again is repeated until a preset end condition is met, thereby obtaining the multiple charge-discharge total capacities and the state of charge difference corresponding to each charge-discharge total capacity.

9. An electronic device, characterized in that: include: 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 method for estimating the health status of a battery as described in any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the battery health status estimation method as described in any one of claims 1 to 6.

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