A method, device, equipment and medium for detecting state of health (SOH) of a battery module

Abstract

This application discloses a method, apparatus, equipment, and medium for detecting the State of Harm (SOH) of a battery module, belonging to the field of new energy technology. The method includes: when a target cell in the battery module enters the charging platform area; if the temperature of the target cell is within a first preset range and its charging current reaches a stable state, the real internal resistance of the target cell is detected using EIS to obtain the target internal resistance; the internal resistance growth rate of the target cell at the current moment is determined based on the target internal resistance; and the SOH of the battery module is determined based on the internal resistance growth rate and a preset mapping relationship; the preset mapping relationship is a mapping relationship between the internal resistance growth rate of the target cell and the SOH created based on the experimental operation data and historical operation data of the target test cell. This method can not only reduce the complexity of detecting the SOH of the battery module, but also improve the detection accuracy of the battery module SOH and increase the versatility of the detection method in practical applications.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a method, apparatus, equipment and medium for detecting SOH of a battery module. Background Technology

[0002] With the rapid development of new energy technology, people are paying increasing attention to the performance and reliability of battery modules. Since SOH (State of Health) reflects the performance degradation of battery modules, such as capacity decay and increased internal resistance, as time and the number of charge-discharge cycles increase, accurate assessment of battery module SOH is of great significance.

[0003] In existing technologies, one method for detecting the State of Health (SOH) of a battery module is to assess its health status through characteristics such as open-circuit voltage, full charge / discharge capacity, and charge / discharge curves. However, this method is time-consuming and requires artificially creating specific operating conditions, leading to significant errors in the SOH detection results. Another method is to detect the SOH based on the equivalent circuit model of the battery module or data-driven AI (Artificial Intelligence) algorithms. However, this method is computationally complex and lacks versatility, making it difficult to apply to real-world operating conditions. Currently, there is no effective solution to this technical problem.

[0004] Therefore, it is evident that providing a simple, generalizable, and highly accurate method for detecting the state of harm (SOH) of battery modules is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method, apparatus, device, and medium for detecting the state of harmonics (SOH) of a battery module, to solve the technical problems of complex calculations, low accuracy of detection results, and poor generalization performance in existing battery module SOH detection methods. The specific solution is as follows:

[0006] To address the aforementioned technical problems, this invention provides a method for detecting the state of harm (SOH) of a battery module, comprising:

[0007] When a target cell in the battery module enters the charging platform area; the target cell can be any one of the cells in the battery module.

[0008] If the temperature of the target battery cell is within a first preset range and the charging current of the target battery cell reaches a stable state, then the real internal resistance of the target battery cell is detected by EIS to obtain the target internal resistance.

[0009] The internal resistance growth rate of the target cell at the current moment is determined based on the target internal resistance, and the SOH of the battery module is determined based on the internal resistance growth rate of the target cell at the current moment and a preset mapping relationship; the preset mapping relationship is a mapping relationship between the internal resistance growth rate of the target cell and the SOH created based on the experimental operation data of the target test cell and the historical operation data of the target cell; the target test cell is a cell of the same type as the target cell.

[0010] Preferably, the process of creating the preset mapping relationship includes:

[0011] Based on the experimental operation data of the target test cell, a mapping relationship between the internal resistance growth rate and SOH of the target test cell is created to obtain an initial preset mapping relationship;

[0012] The initial preset mapping relationship is corrected using the historical operating data of the target battery cell to obtain the optimized preset mapping relationship.

[0013] Preferably, the step of creating a mapping relationship between the internal resistance growth rate and the state of harmonics (SOH) of the target test cell based on the experimental operation data of the target test cell, to obtain an initial preset mapping relationship, includes:

[0014] The target test cell was subjected to charge-discharge testing;

[0015] When the target test cell enters the charging platform area, the real internal resistance of the target test cell is detected by the EIS to obtain the initial internal resistance of the target test cell.

[0016] When the target test cell finishes the charge-discharge test, the ampere-hour integral value of the target test cell from the moment of charge depletion to the moment of charge full-charge is determined, and the maximum usable capacity of the target test cell is obtained.

[0017] Repeat the steps of charging and discharging the target test cell to obtain the real internal resistance and ampere-hour integral of the target test cell under different charging and discharging test cycles, until the SOH of the target test cell drops to a preset value, and obtain the target internal resistance data and target integral data;

[0018] Based on the initial internal resistance of the target test cell, the maximum usable capacity of the target test cell, the target internal resistance data, and the target integral data, a mapping relationship between the internal resistance growth rate and SOH of the target test cell is created to obtain the initial preset mapping relationship.

[0019] Preferably, before creating the mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the experimental operation data of the target test cell, and obtaining the initial preset mapping relationship, the method further includes:

[0020] Abnormal operating data in the experimental operating data of the target test cell are removed.

[0021] Preferably, the step of correcting the initial preset mapping relationship using the historical operating data of the target battery cell to obtain the optimized preset mapping relationship includes:

[0022] When the target battery cell first enters the charging platform area;

[0023] If the temperature of the target battery cell is within the first preset range and the charging current of the target battery cell reaches a stable state, then the real internal resistance of the target battery cell is detected by the EIS to obtain the initial internal resistance of the target battery cell.

[0024] When the target battery cell is not entering the charging platform area for the first time;

[0025] If the temperature of the target battery cell is within the first preset range and the charging current of the target battery cell reaches a stable state, then the real internal resistance of the target battery cell is detected by the EIS to obtain the real internal resistance of the target battery cell at the current moment, and recorded in the historical operating data of the target battery cell.

[0026] When the target battery cell is operating normally, the ampere-hour integral value of the target battery cell at each moment is recorded and added to the historical operating data of the target battery cell;

[0027] The target battery cell's historical operating data is filtered to obtain a target filtering time period sequence that meets preset conditions. The preset conditions include: the target battery cell is charged from a discharged state to a fully charged state; the target battery cell is charged at a rate within a preset range; the ambient temperature of the target battery cell during the charging process is within a second preset range; and EIS detection is performed on the target battery cell during the period from a discharged state to a fully charged state.

[0028] Filter at least one time period from the filtered time period sequence to obtain a set of filtered time periods;

[0029] The real internal resistance of the target battery cell in each time period of the screening time period set is obtained from the historical operating data of the target battery cell, and the internal resistance growth rate of the target battery cell in each time period of the screening time period set is determined based on the real internal resistance of the target battery cell in each time period of the screening time period set and the initial internal resistance of the target battery cell.

[0030] Determine the ampere-hour integral value of the target battery cell in each time period of the screening time period set, and determine the SOH of the target battery cell in each time period of the screening time period set based on the ampere-hour integral value of the target battery cell in each time period of the screening time period set;

[0031] The initial preset mapping relationship is corrected based on the internal resistance growth rate of the target battery cell in each time period of the screening time period set and the SOH of the target battery cell in each time period of the screening time period set to obtain the optimized preset mapping relationship.

[0032] Preferably, the set of filtered time periods contains one element, and the element in the set of filtered time periods is the target time period.

[0033] Preferably, the step of correcting the initial preset mapping relationship based on the internal resistance growth rate of the target battery cell in each time period of the screening time period set and the SOH of the target battery cell in each time period of the screening time period set to obtain the optimized preset mapping relationship includes:

[0034] Find the internal resistance growth rate corresponding to the SOH of the target cell in the target time period from the initial preset mapping relationship to obtain the target search growth rate;

[0035] The ratio between the internal resistance growth rate of the target cell during the target time period and the target search growth rate is calculated to obtain the target ratio. The target ratio is then used to correct the initial preset mapping relationship to obtain the optimized preset mapping relationship.

[0036] To address the aforementioned technical problems, this invention provides a battery module SOH detection device, comprising:

[0037] A cell triggering module is used when a target cell in the battery module enters the charging platform area; the target cell is any one of the cells in the battery module.

[0038] An internal resistance detection module is used to detect the real internal resistance of the target battery cell using EIS if the temperature of the target battery cell is within a first preset range and the charging current of the target battery cell reaches a stable state, thereby obtaining the target internal resistance.

[0039] The SOH determination module is used to determine the internal resistance growth rate of the target cell at the current moment based on the target internal resistance, and to determine the SOH of the battery module based on the internal resistance growth rate of the target cell at the current moment and a preset mapping relationship. The preset mapping relationship is created by a relationship creation module, which is used to create a mapping relationship between the internal resistance growth rate and SOH of the target cell based on the experimental operation data of the target test cell and the historical operation data of the target cell. The target test cell is a cell of the same type as the target cell.

[0040] To address the aforementioned technical problems, the present invention provides an electronic device, comprising:

[0041] Memory, used to store computer programs;

[0042] A processor is configured to execute the computer program to implement the steps of a method for detecting the state of harm (SOH) of a battery module as disclosed above.

[0043] To address the aforementioned technical problems, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a battery module SOH detection method as disclosed above.

[0044] Beneficial effects: In the battery module SOH detection method provided by this invention, a mapping relationship between the internal resistance growth rate of the target battery cell and SOH is pre-established based on the experimental operation data and historical operation data of the target battery cell, thus obtaining a preset mapping relationship. When the target battery cell enters the charging platform area in the battery module, if the temperature of the target battery cell is within a first preset range and the charging current of the target battery cell reaches a stable state, the real internal resistance of the target battery cell is detected using EIS to obtain the target internal resistance; then, the internal resistance growth rate of the target battery cell at the current moment is determined based on the target internal resistance, and the SOH of the battery module is determined based on the internal resistance growth rate of the target battery cell at the current moment and the preset mapping relationship.

[0045] Compared to existing technologies, this method uses experimental modeling and historical operating data of the target cell to create a target mapping relationship between the internal resistance growth rate and the state of equilibrium (SOH) of the target cell. This improves the accuracy and reliability of the target mapping relationship creation results. Furthermore, when using EIS to detect the real internal resistance of the target cell, it is not affected by different operating conditions of the battery module, and has lower requirements for the actual operating conditions of the battery module. In the process of detecting the SOH of the battery module, it is only necessary to calculate the internal resistance growth rate of the target cell at the current moment based on the real internal resistance of the target cell, and determine the SOH of the battery module based on the internal resistance growth rate of the target cell at the current moment and the preset mapping relationship. This not only reduces the computational complexity of detecting the SOH of the battery module, but also improves the detection accuracy of the battery module's SOH and increases the versatility of the SOH detection method provided in this application in practical applications.

[0046] Correspondingly, the battery module SOH detection device, equipment, and medium provided in this application also have the above-mentioned beneficial effects. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0048] Figure 1 A flowchart illustrating a method for detecting SOH in a battery module according to an embodiment of the present invention;

[0049] Figure 2 This is a structural diagram of a battery module SOH detection device provided in an embodiment of the present invention;

[0050] Figure 3 This is a structural diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Please see Figure 1 , Figure 1This is a flowchart of a method for detecting SOH (State of Health) in a battery module according to an embodiment of the present invention. The method includes:

[0053] Step S11: When the target cell in the battery module enters the charging platform area; the target cell is any cell in the battery module;

[0054] Step S12: If the temperature of the target cell is within the first preset range and the charging current of the target cell reaches a stable state, then the real internal resistance of the target cell is detected by EIS to obtain the target internal resistance.

[0055] Step S13: Determine the internal resistance growth rate of the target cell at the current moment based on the target internal resistance, and determine the SOH of the battery module based on the internal resistance growth rate of the target cell at the current moment and the preset mapping relationship; the preset mapping relationship is the mapping relationship between the internal resistance growth rate of the target cell and the SOH created based on the experimental operation data and historical operation data of the target cell; the target test cell is a cell of the same type as the target cell.

[0056] This embodiment provides a method for detecting the SOH of a battery module. Using this method to detect the SOH of the battery module can not only reduce the computational complexity of detecting the SOH of the battery module, but also improve the detection accuracy of the SOH of the battery module, and increase the versatility of the SOH detection method provided in this application in practical applications.

[0057] This method requires the pre-established mapping relationship, that is, the mapping relationship between the internal resistance growth rate and the state of equilibrium (SOH) of the target battery cell needs to be created in advance based on the experimental operation data and historical operation data of the target battery cell. The target test battery cell is a battery cell of the same type as the target battery cell.

[0058] It should be noted that the target cell is any one cell in the battery module. A battery module contains multiple cells, which are usually from the same batch and of the same type, with basically the same operating performance. Therefore, the state of harmonics (SOH) of the target cell can be used to characterize the state of harmonics (SOH) of the battery module.

[0059] Experimental studies have shown that as the usage of a battery cell increases, the SOH of the cell gradually decreases. Although the initial internal resistance of cells produced in the same batch may vary slightly, the decreasing trend of SOH is basically the same for each cell as the usage increases. Therefore, based on the experimental operation data of the target test cell and the historical operation data of the target cell, a mapping relationship between the growth rate of the internal resistance of the target cell and SOH can be established.

[0060] Specifically, since the target test cell and the target cell are of the same type, under experimental conditions, the experimental operating data of the target test cell can be used to roughly infer the mapping relationship between the internal resistance growth rate and the state of equilibrium (SOH) of the target cell. Furthermore, by combining this with the actual historical operating data of the target cell, the mapping relationship between the internal resistance growth rate and SOH of the target cell can be accurately and reliably established, thus obtaining the preset mapping relationship.

[0061] Once the mapping relationship between the internal resistance growth rate of the target cell and the state of charge (SOH) is established and the preset mapping relationship is obtained, the operating status of the battery module is detected. When the target cell in the battery module enters the charging platform area, if the temperature of the target cell is within the first preset range and the charging current of the target cell reaches a stable state, the real internal resistance of the target cell is detected by EIS to obtain the target internal resistance.

[0062] Among them, "the target cell enters the charging platform zone" means that the target cell's SOC is between 40% and 60%, "the target cell's temperature is within the first preset range" means that the target cell's temperature is between 20℃ and 30℃, and "the target cell's charging current reaches a stable state" means that the target cell's charging current remains unchanged within 5 to 10 minutes.

[0063] EIS (Electrochemical Impedance Spectroscopy) is a method for measuring the impedance of a battery cell by applying periodic perturbations within a certain frequency range to the target cell. This method can detect the real internal resistance of the target cell anytime and anywhere, without being affected by the operating conditions of the battery module. In this embodiment, when using EIS to detect the real internal resistance of the target cell, periodic perturbations of 1Hz to 1000Hz are applied to the target cell.

[0064] After obtaining the target internal resistance by detecting the real internal resistance of the target cell using EIS, the internal resistance growth rate of the target cell at the current moment is determined based on the target internal resistance. The formula for calculating the internal resistance growth rate of the target cell at the current moment is as follows:

[0065] R i =(rr init ) / r init *100%;

[0066] In the formula, R i Let r be the rate of increase of the internal resistance of the target cell at the current moment, and r be the target internal resistance. init The initial internal resistance value of the target battery cell.

[0067] The initial internal resistance value of the target cell refers to the internal resistance value detected when the target cell is first activated by EIS in its factory state. The triggering conditions for the first activation of EIS detection are that the target cell enters the charging platform area, the temperature of the target cell is within the first preset range, and the charging current of the target cell reaches a stable state.

[0068] Since the preset mapping relationship stores the mapping relationship between the internal resistance growth rate of the target cell and the state of harmonics (SOH), when the internal resistance growth rate of the target cell at the current moment is determined, the SOH corresponding to the internal resistance growth rate of the target cell at the current moment can be found from the preset mapping relationship, thereby determining the SOH of the target cell, that is, determining the SOH of the battery module.

[0069] Compared to existing technologies, this method improves the accuracy and reliability of the target mapping relationship by pre-establishing a target mapping relationship between the internal resistance growth rate and the state of equilibrium (SOH) of the target cell using experimental modeling and historical operating data of the target cell. Furthermore, when using EIS to detect the real internal resistance of the target cell, it is not affected by different operating conditions of the battery module, thus having lower requirements for the actual operating conditions of the battery module. During the SOH detection of the battery module, it is only necessary to calculate the internal resistance growth rate of the target cell at the current moment based on its real internal resistance, and determine the SOH of the battery module based on the target cell's internal resistance growth rate at the current moment and the preset mapping relationship. This not only reduces the computational complexity of SOH detection but also improves the detection accuracy and increases the versatility of the SOH detection method provided in this application in practical applications.

[0070] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. As a preferred implementation, the process of creating the above-mentioned preset mapping relationship includes:

[0071] Based on the experimental operation data of the target test cell, a mapping relationship between the internal resistance growth rate and SOH of the target test cell is created to obtain the initial preset mapping relationship;

[0072] The initial preset mapping relationship is corrected by using the historical operating data of the target battery cell to obtain the optimized preset mapping relationship.

[0073] In this embodiment, when creating the preset mapping relationship, the first step is to create a mapping relationship between the internal resistance growth rate and the state of harmonics (SOH) of the target test cell based on the experimental operation data of the target test cell, thereby obtaining the initial preset mapping relationship.

[0074] Because the experimental operation data of the target test cell can only characterize the operating state of the target test cell under ideal experimental conditions, the mapping relationship between the internal resistance growth rate and SOH of the target test cell created based on the experimental operation data can only roughly characterize the mapping relationship between the internal resistance growth rate and SOH of the target cell under ideal conditions, and cannot accurately characterize the mapping relationship between the internal resistance growth rate and SOH of the target cell under real operating conditions.

[0075] Furthermore, in practical applications, differences in charge / discharge depth, rate of change, and ambient temperature can lead to inconsistent aging paths among battery cells. Consequently, the mapping relationship between the internal resistance growth rate and state of equilibrium (SOH) varies to different cells. To ensure that the established preset mapping relationship more accurately and reliably characterizes the mapping relationship between the internal resistance growth rate and SOH of the target battery cell under real-world operating conditions, it is necessary to use historical operating data that characterizes the actual operating state of the target battery cell to correct the initial preset mapping relationship, thereby obtaining an optimized preset mapping relationship.

[0076] Obviously, the technical solution provided in this embodiment can guarantee the accuracy and reliability of the created preset mapping relationship.

[0077] As a preferred embodiment, the above steps include: creating a mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the experimental operation data of the target test cell, and obtaining an initial preset mapping relationship, including:

[0078] Perform charge-discharge tests on the target battery cell;

[0079] When the target test cell enters the charging platform area, the real internal resistance of the target test cell is detected by EIS to obtain the initial internal resistance of the target test cell.

[0080] When the target test cell finishes the charge and discharge test, determine the ampere-hour integral value of the target test cell from the moment of charge depletion to the moment of charge full-charge, and obtain the maximum usable capacity of the target test cell;

[0081] Repeat the steps of charging and discharging the target test cell to obtain the real internal resistance and ampere-hour integral of the target test cell under different charging and discharging test rounds until the SOH of the target test cell drops to the preset value, and obtain the target internal resistance data and target integral data;

[0082] Based on the initial internal resistance of the target test cell, the maximum usable capacity of the target test cell, the target internal resistance data, and the target integral data, a mapping relationship between the internal resistance growth rate and the state of equilibrium (SOH) of the target test cell is created, and an initial preset mapping relationship is obtained.

[0083] In this embodiment, when creating the initial preset mapping relationship based on the experimental operation data of the target test cell, the target test cell is first charged and discharged at a certain rate under an ambient temperature of 25°C. When the target test cell enters the charging platform area, the real internal resistance of the target test cell is detected by EIS to obtain the initial internal resistance of the target test cell.

[0084] Then, the charge-discharge test steps for the target test cell are repeated to obtain the real internal resistance and ampere-hour integral of the target test cell under different charge-discharge test cycles, until the SOH of the target test cell drops to a preset value, thus obtaining the target internal resistance data and target integral data. The target internal resistance data is the real internal resistance of the target test cell under all test cycles, while the target integral data is the ampere-hour integral of the target test cell across all test cycles.

[0085] Once the initial internal resistance, maximum usable capacity, target internal resistance data, and target integral data of the target test cell are obtained, the internal resistance growth rate and SOH of the target test cell under different charge and discharge test periods can be determined.

[0086] The internal resistance growth rate of the target test cell during the Tth round of charge-discharge testing is as follows:

[0087] R T = (r n -r0) / r0 *100%;

[0088] In the formula, R T Let r be the rate of increase in internal resistance of the target test cell during the Tth round of charge-discharge testing. n Let r be the real internal resistance of the target test cell during the Tth round of charge-discharge testing, and r0 be the initial internal resistance of the target test cell.

[0089] It should be noted that since the rate of change of the real internal resistance of the target test cell is small during each round of charge and discharge testing, it can be basically assumed that the real internal resistance of the target test cell remains unchanged during each round of charge and discharge testing. Therefore, in practical applications, the real internal resistance of the target test cell at any moment during the Tth round of charge and discharge testing can be determined as the real internal resistance of the target test cell during the Tth round of charge and discharge testing.

[0090] Of course, in practical applications, in order to further ensure the accuracy and reliability of the real internal resistance of the target test cell during the Tth round of charge-discharge test, the average value of the real internal resistance of the target test cell at each moment during the Tth round of charge-discharge test can be determined as the real internal resistance of the target test cell during the Tth round of charge-discharge test.

[0091] The SOH of the target test cell during the Tth round of charge-discharge testing is:

[0092] SOH=Q n / Q0*100%;

[0093] In the formula, SOH is the SOH corresponding to the target test cell during the Tth round of charge-discharge test, and Q... n Q0 represents the ampere-hour integral value of the target test cell during the Tth round of charge-discharge testing, and Q0 represents the initial maximum usable capacity of the target test cell, which is the ampere-hour integral value during the 1st round of testing.

[0094] The above calculation formula can be used to determine the internal resistance growth rate and SOH of the target test cell under different charge and discharge tests. Then, by arranging these corresponding arrays, the initial preset mapping relationship can be accurately created.

[0095] Obviously, the initial preset mapping relationship can be accurately created through the technical solution provided in this embodiment.

[0096] As a preferred embodiment, before the above steps—creating a mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the experimental operation data of the target test cell and obtaining the initial preset mapping relationship—also include:

[0097] Abnormal operating data in the experimental operation data of the target test cell were removed.

[0098] It is understandable that in practical applications, due to the influence of factors such as environment, noise and data acquisition equipment, there will inevitably be some abnormal operating data in the experimental operation data of the target test cell. The existence of abnormal operating data will inevitably affect the accuracy and reliability of the initial preset mapping relationship creation results.

[0099] Therefore, in order to further improve the accuracy and reliability of the initial preset mapping relationship creation results, abnormal operating data in the experimental operating data of the target test cell can be removed before creating the initial preset mapping relationship, so as to eliminate the influence of accidental factors on the initial preset mapping relationship creation results.

[0100] Clearly, the technical solution provided in this embodiment can further improve the accuracy and reliability of the preset mapping relationship creation results.

[0101] As a preferred embodiment, the above step of correcting the initial preset mapping relationship using historical operating data of the target battery cell to obtain an optimized preset mapping relationship includes:

[0102] When the target battery cell first enters the charging platform area;

[0103] If the temperature of the target cell is within the first preset range and the charging current of the target cell reaches a stable state, the real internal resistance of the target cell is detected by EIS to obtain the initial internal resistance of the target cell.

[0104] When the target battery cell is not entering the charging platform area for the first time;

[0105] If the temperature of the target cell is within the first preset range and the charging current of the target cell reaches a stable state, the real internal resistance of the target cell is detected by EIS to obtain the real internal resistance of the target cell at the current moment and record it in the historical operating data of the target cell.

[0106] When the target cell is operating normally, record the ampere-hour integral value of the target cell at each moment and record it in the historical operating data of the target cell;

[0107] The target battery cell's historical operating data is filtered to obtain the target selection time period sequence, which meets the preset conditions. The preset conditions include: the target battery cell is charged from a state of depletion to a state of full charge; the target battery cell is charged at a rate within a preset range; the ambient temperature of the target battery cell during the charging process is within a second preset range; and EIS detection is performed on the target battery cell during the period from a state of depletion to a state of full charge.

[0108] Filter at least one time period from the filtered time period sequence to obtain a set of filtered time periods;

[0109] The real internal resistance of the target battery cell in each time period of the screening time period set is obtained from the historical operating data of the target battery cell, and the internal resistance growth rate of the target battery cell in each time period of the screening time period set is determined based on the real internal resistance of the target battery cell in each time period of the screening time period set and the initial internal resistance of the target battery cell.

[0110] Determine the ampere-hour integral value of the target cell in each time period of the screening time period set, and determine the SOH of the target cell in each time period of the screening time period set based on the ampere-hour integral value of the target cell in each time period of the screening time period set;

[0111] The initial preset mapping relationship is corrected based on the internal resistance growth rate and the state of harm (SOH) of the target cell in each time period of the screening time period set, to obtain the optimized preset mapping relationship.

[0112] In this embodiment, when correcting the initial preset mapping relationship using the historical operating data of the target cell, the initial internal resistance of the target cell is first obtained. That is, when the target cell first enters the charging platform area, if the temperature of the target cell is within a first preset range and the charging current of the target cell reaches a stable state, the real internal resistance of the target cell is detected using EIS to obtain the initial internal resistance of the target cell.

[0113] Specifically, "target cell entering the charging platform zone" means the target cell's SOC is between 40% and 60%; "target cell temperature within the first preset range" means the target cell's temperature is between 20℃ and 30℃; and "target cell charging current reaching a stable state" means the target cell's charging current remains constant for 5 to 10 minutes. When using EIS to detect the real internal resistance of the target cell, a periodic perturbation of 1Hz to 1000Hz is applied to the target cell.

[0114] Secondly, operational data that meets preset conditions is selected from the historical operational data of the target cell to obtain target screening data, which is then used to correct the initial preset mapping relationship. The preset conditions include: the target cell is charged from a discharged state to a fully charged state; the target cell is charged at a rate within a preset range; the ambient temperature of the target cell during charging is within a second preset range; and EIS detection is performed during the charging process from a discharged state to a fully charged state.

[0115] Charging the target battery cell at a rate within the preset range means charging the target battery cell at a rate of 0.05 to 0.5. The ambient temperature of the target battery cell during the charging process being within the second preset range means that the ambient temperature of the target battery cell during the charging process is between 15°C and 40°C.

[0116] After filtering the target screening data from the historical operating data of the target battery cell, the time period corresponding to when the target battery cell enters the charging platform area, the temperature of the target battery cell is within the first preset range, and the charging current of the target battery cell reaches a stable state is determined based on the target screening data, thus obtaining the screening time period sequence.

[0117] Then, at least one moment is selected from the selected time period sequence to obtain a set of selected time periods. That is, the set of selected time periods contains at least one element. After obtaining the set of selected time periods, EIS is used to detect the real internal resistance of the target cell in each time period of the set of selected time periods, and the internal resistance growth rate of the target cell in each time period of the set of selected time periods is determined based on the real internal resistance of the target cell in each time period of the set of selected time periods and the initial internal resistance of the target cell.

[0118] The internal resistance growth rate of the target cell in the selected i-th time period is:

[0119] Ri_real = (r i -r inti ) / r inti *100%;

[0120] In the formula, Ri_real represents the internal resistance growth rate of the target cell in the i-th time period during which it is selected, and r i Let r be the real internal resistance of the target cell in the i-th time period during the selection process. inti Let be the initial internal resistance of the target battery cell. The i-th time period selected for the target battery cell is any element in the set of selected time periods.

[0121] Next, the ampere-hour integral value of the target battery cell in the selected i-th time period is determined, and the state of charge (SOH) of the target battery cell in each time period of the selected time period set is determined based on the ampere-hour integral value of the target battery cell in the selected i-th time period. The SOH corresponding to the target battery cell in the selected i-th time period is:

[0122] SOH = Qi / Cap * 100%;

[0123] In the formula, SOH is the SOH of the target cell in the i-th time period of the selection, Qi is the ampere-hour integral of the target cell in the i-th time period of the selection, and Cap is the nominal capacity of the target cell.

[0124] Once the internal resistance growth rate and the state of harmonics (SOH) of the target cell in each time period of the screening time period set are determined, it is equivalent to determining the internal resistance growth rate and SOH of the target cell under actual operating conditions. At this point, these arrays can be used to correct the initial preset mapping relationship and obtain an optimized preset mapping relationship.

[0125] It is easy to see that the more elements in the set of time periods being filtered, the more accurately the initial preset mapping relationship can be corrected using the array in the set of time periods, thereby further improving the accuracy and reliability of the preset mapping relationship creation results.

[0126] Clearly, the technical solution provided in this embodiment can accurately create a preset mapping relationship.

[0127] In a preferred implementation, the set of selected time periods contains only one element, and this element is the target time period. Since the initial preset mapping relationship is essentially a function curve relating the internal resistance growth rate and the state of equilibrium (SOH) of the target cell, and the slope of this curve changes very little, to reduce the resource overhead required when creating the preset mapping relationship, only the internal resistance growth rate and SOH corresponding to one time period within the selected time period set are needed to correct the initial preset mapping relationship. That is, the number of elements in the selected time period set can be set to one, and the element in the selected time period set can be named the target time period.

[0128] As a preferred implementation, the initial preset mapping relationship is corrected based on the internal resistance growth rate and the state of harm (SOH) of the target cell in each time period of the screening time period set, to obtain an optimized preset mapping relationship, including:

[0129] Find the internal resistance growth rate corresponding to the SOH of the target cell in the target time period from the initial preset mapping relationship, and obtain the target search growth rate;

[0130] The ratio between the growth rate of the internal resistance of the target cell during the target time period and the growth rate of the target search is obtained to obtain the target ratio. The initial preset mapping relationship is then corrected using the target ratio to obtain the optimized preset mapping relationship.

[0131] In this embodiment, when correcting the initial preset mapping relationship using the internal resistance growth rate and SOH of the target cell in the target time period, the internal resistance growth rate corresponding to the SOH of the target cell in the target time period can be found from the initial preset mapping relationship to obtain the target search growth rate; then, the ratio between the internal resistance growth rate of the target cell at the target time and the target search growth rate can be calculated to obtain the target ratio.

[0132] The formula for calculating the target ratio is as follows:

[0133] b = Ri_real / Ri_map;

[0134] In the formula, b is the target ratio, Ri_real is the internal resistance growth rate of the target cell during the target time period, and Ri_map is the target search growth rate.

[0135] Once the target ratio is determined, multiplying all internal resistance growth rates in the initial preset mapping relationship by the target ratio will correct the initial preset mapping relationship, thus allowing the preset mapping relationship to be obtained accurately and reliably.

[0136] Obviously, the technical solution provided in this embodiment can accurately and reliably create a preset mapping relationship between the target cell internal resistance growth rate and SOH.

[0137] Please see Figure 2 , Figure 2 This is a structural diagram of a battery module SOH detection device provided in an embodiment of the present invention. The device includes:

[0138] The cell triggering module 21 is used when a target cell in the battery module enters the charging platform area; the target cell is any one of the cells in the battery module.

[0139] The internal resistance detection module 22 is used to detect the real internal resistance of the target battery cell using EIS if the temperature of the target battery cell is within a first preset range and the charging current of the target battery cell reaches a stable state, thereby obtaining the target internal resistance.

[0140] SOH determination module 23 is used to determine the internal resistance growth rate of the target cell at the current moment based on the target internal resistance, and to determine the SOH of the battery module based on the internal resistance growth rate of the target cell at the current moment and a preset mapping relationship; the preset mapping relationship is created by the relationship creation module, which is used to create a mapping relationship between the internal resistance growth rate of the target cell and the SOH based on the experimental operation data of the target test cell and the historical operation data of the target cell; the target test cell is a cell of the same type as the target cell.

[0141] Preferably, the relationship creation module includes:

[0142] The initial submodule is used to create a mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the experimental operation data of the target test cell, and obtain an initial preset mapping relationship;

[0143] The correction submodule is used to correct the initial preset mapping relationship using the historical operating data of the target battery cell, so as to obtain the preset mapping relationship.

[0144] Preferably, the initial submodule includes:

[0145] A charge / discharge test unit is used to perform charge / discharge tests on the target test cell.

[0146] An internal resistance detection unit is used to detect the real internal resistance of the target test cell when the target test cell enters the charging platform area using the EIS, so as to obtain the initial internal resistance of the target test cell.

[0147] The integral quantity determination unit is used to determine the ampere-hour integral quantity of the target test cell from the moment of charge depletion to the moment of charge full-charge when the target test cell finishes the charge-discharge test, so as to obtain the maximum usable capacity of the target test cell.

[0148] The repeated test unit is used to repeatedly execute the steps of charging and discharging the target test cell to obtain the real internal resistance and ampere-hour integral of the target test cell under different charging and discharging test rounds, until the SOH of the target test cell drops to a preset value, and the target internal resistance data and target integral data are obtained.

[0149] The initial relationship creation unit is used to create a mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the initial internal resistance of the target test cell, the maximum usable capacity of the target test cell, the target internal resistance data, and the target integral data, thereby obtaining the initial preset mapping relationship.

[0150] Preferred options also include:

[0151] The data rejection unit is used to create a mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the experimental operation data of the target test cell. Before obtaining the initial preset mapping relationship, abnormal operation data in the experimental operation data of the target test cell is rejected.

[0152] Preferably, the correction submodule includes:

[0153] A condition triggering unit is used when the target battery cell first enters the charging platform area;

[0154] An internal resistance measurement unit is used to detect the real internal resistance of the target battery cell using the EIS if the temperature of the target battery cell is within the first preset range and the charging current of the target battery cell reaches a stable state, thereby obtaining the initial internal resistance of the target battery cell.

[0155] A test initiation unit is used when the target battery cell is not entering the charging platform area for the first time;

[0156] The first recording unit is used to detect the real internal resistance of the target battery cell using the EIS if the temperature of the target battery cell is within the first preset range and the charging current of the target battery cell reaches a stable state, obtain the real internal resistance of the target battery cell at the current moment, and record it in the historical operating data of the target battery cell.

[0157] The second recording unit is used to record the ampere-hour integral of the target battery cell at each moment when the target battery cell is operating normally, and to record it in the historical operating data of the target battery cell;

[0158] A data filtering unit is used to filter operating data that meets preset conditions from the historical operating data of the target battery cell to obtain a time period sequence of the target filtered data; the preset conditions include: the target battery cell is charged from a discharged state to a fully charged state, the target battery cell is charged at a rate within a preset range, the ambient temperature of the target battery cell during the charging process is within a second preset range, and EIS detection is performed on the target battery cell during the period from a discharged state to a fully charged state.

[0159] A set determination unit is used to filter at least one moment from the filtered time period sequence to obtain a filtered time period set;

[0160] The growth rate determination unit is used to obtain the real internal resistance of the target battery cell in each time period of the screening time period set from the historical operating data of the target battery cell, and to determine the internal resistance growth rate of the target battery cell in each time period of the screening time period set based on the real internal resistance of the target battery cell in each time period of the screening time period set and the initial internal resistance of the target battery cell.

[0161] The SOH determination unit is used to determine the ampere-hour integral value of the target battery cell in each time period of the screening time period set, and to determine the SOH of the target battery cell in each time period of the screening time period set based on the ampere-hour integral value of the target battery cell in each time period of the screening time period set.

[0162] The mapping relationship creation unit is used to correct the initial preset mapping relationship based on the internal resistance growth rate of the target battery cell in each time period of the screening time period set and the SOH of the target battery cell in each time period of the screening time period set, so as to obtain the optimized preset mapping relationship.

[0163] Preferably, the mapping relationship creation unit includes:

[0164] The growth rate lookup subunit is used to look up the internal resistance growth rate corresponding to the SOH of the target cell in the target time period from the initial preset mapping relationship, and obtain the target lookup growth rate;

[0165] The relationship correction subunit is used to calculate the ratio between the internal resistance growth rate of the target cell in the target time period and the target search growth rate, obtain the target ratio, and use the target ratio to correct the initial preset mapping relationship to obtain the optimized preset mapping relationship.

[0166] The battery module SOH detection device provided in this embodiment of the invention has the beneficial effects of the battery module SOH detection method disclosed above.

[0167] Please see Figure 3 , Figure 3 This is a structural diagram of an electronic device provided in an embodiment of the present invention. The device includes:

[0168] Memory 31 is used to store computer programs;

[0169] The processor 32 is configured to execute the computer program to implement the steps of a battery module SOH detection method as disclosed above.

[0170] The electronic device provided in this embodiment of the invention has the beneficial effects of the aforementioned method for detecting SOH in a battery module.

[0171] Accordingly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a battery module SOH detection method as disclosed above.

[0172] The method for detecting SOH of a battery module provided in this embodiment of the invention has the beneficial effects of the aforementioned method for detecting SOH of a battery module.

[0173] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0174] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0175] The present invention provides a detailed description of a method, apparatus, device, and medium for detecting SOH in a battery module. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for detecting the state of harmonics (SOH) of a battery module, characterized in that, include: When the target cell in the battery module enters the charging platform area; The target cell is any one of the cells in the battery module; If the temperature of the target battery cell is within a first preset range and the charging current of the target battery cell reaches a stable state, then the real internal resistance of the target battery cell is detected by EIS to obtain the target internal resistance. The internal resistance growth rate of the target cell at the current moment is determined based on the target internal resistance, and the SOH of the battery module is determined based on the internal resistance growth rate of the target cell at the current moment and a preset mapping relationship; the preset mapping relationship is a mapping relationship between the internal resistance growth rate of the target cell and the SOH created based on the experimental operation data of the target test cell and the historical operation data of the target cell; the target test cell is a cell of the same type as the target cell.

2. The method of claim 1, wherein the method comprises: The process of creating the preset mapping relationship includes: Based on the experimental operation data of the target test cell, a mapping relationship between the internal resistance growth rate and SOH of the target test cell is created to obtain an initial preset mapping relationship; The initial preset mapping relationship is corrected using the historical operating data of the target battery cell to obtain the optimized preset mapping relationship.

3. The method of claim 2, wherein the method further comprises: The step of creating a mapping relationship between the internal resistance growth rate and the state of harmonics (SOH) of the target test cell based on the experimental operation data of the target test cell, and obtaining an initial preset mapping relationship, includes: The target test cell was subjected to charge-discharge testing; When the target test cell enters the charging platform area, the real internal resistance of the target test cell is detected by the EIS to obtain the initial internal resistance of the target test cell. When the target test cell finishes the charge-discharge test, the ampere-hour integral value of the target test cell from the moment of charge depletion to the moment of charge full-charge is determined, and the maximum usable capacity of the target test cell is obtained. Repeat the steps of charging and discharging the target test cell to obtain the real internal resistance and ampere-hour integral of the target test cell under different charging and discharging test cycles, until the SOH of the target test cell drops to a preset value, and obtain the target internal resistance data and target integral data; Based on the initial internal resistance of the target test cell, the maximum usable capacity of the target test cell, the target internal resistance data, and the target integral data, a mapping relationship between the internal resistance growth rate and SOH of the target test cell is created to obtain the initial preset mapping relationship.

4. The method of claim 2, wherein the method further comprises: Before creating the mapping relationship between the internal resistance growth rate and SOH of the target test cell based on the experimental operation data of the target test cell, and obtaining the initial preset mapping relationship, the method further includes: Abnormal operating data in the experimental operating data of the target test cell are removed.

5. The method for detecting SOH of a battery module according to claim 3, characterized in that, The step of correcting the initial preset mapping relationship using the historical operating data of the target battery cell to obtain the optimized preset mapping relationship includes: When the target battery cell first enters the charging platform area; If the temperature of the target battery cell is within the first preset range and the charging current of the target battery cell reaches a stable state, then the real internal resistance of the target battery cell is detected by the EIS to obtain the initial internal resistance of the target battery cell. When the target battery cell is not entering the charging platform area for the first time; If the temperature of the target battery cell is within the first preset range and the charging current of the target battery cell reaches a stable state, then the real internal resistance of the target battery cell is detected by the EIS to obtain the real internal resistance of the target battery cell at the current moment, and recorded in the historical operating data of the target battery cell. When the target battery cell is operating normally, the ampere-hour integral value of the target battery cell at each moment is recorded and added to the historical operating data of the target battery cell; The target battery cell's historical operating data is filtered to obtain a target filtering time period sequence that meets preset conditions. The preset conditions include: the target battery cell is charged from a discharged state to a fully charged state; the target battery cell is charged at a rate within a preset range; the ambient temperature of the target battery cell during the charging process is within a second preset range; and EIS detection is performed on the target battery cell during the period from a discharged state to a fully charged state. Filter at least one time period from the filtered time period sequence to obtain a set of filtered time periods; The real internal resistance of the target battery cell in each time period of the screening time period set is obtained from the historical operating data of the target battery cell, and the internal resistance growth rate of the target battery cell in each time period of the screening time period set is determined based on the real internal resistance of the target battery cell in each time period of the screening time period set and the initial internal resistance of the target battery cell. Determine the ampere-hour integral value of the target battery cell in each time period of the screening time period set, and determine the SOH of the target battery cell in each time period of the screening time period set based on the ampere-hour integral value of the target battery cell in each time period of the screening time period set; The initial preset mapping relationship is corrected based on the internal resistance growth rate of the target battery cell in each time period of the screening time period set and the SOH of the target battery cell in each time period of the screening time period set to obtain the optimized preset mapping relationship.

6. The method for detecting SOH of a battery module according to claim 5, characterized in that, The set of filtered time periods contains only one element, and the element in the set of filtered time periods is the target time period.

7. The method for detecting SOH of a battery module according to claim 6, characterized in that, The step of correcting the initial preset mapping relationship based on the internal resistance growth rate of the target battery cell in each time period of the screening time period set and the state of harmonics (SOH) of the target battery cell in each time period of the screening time period set to obtain the optimized preset mapping relationship includes: Find the internal resistance growth rate corresponding to the SOH of the target cell in the target time period from the initial preset mapping relationship to obtain the target search growth rate; The ratio between the internal resistance growth rate of the target cell during the target time period and the target search growth rate is calculated to obtain the target ratio. The target ratio is then used to correct the initial preset mapping relationship to obtain the optimized preset mapping relationship.

8. A device for detecting the state of harm (SOH) of a battery module, characterized in that, include: A cell triggering module is used when a target cell in the battery module enters the charging platform area; The target cell is any one of the cells in the battery module; An internal resistance detection module is used to detect the real internal resistance of the target battery cell using EIS if the temperature of the target battery cell is within a first preset range and the charging current of the target battery cell reaches a stable state, thereby obtaining the target internal resistance. The SOH determination module is used to determine the internal resistance growth rate of the target cell at the current moment based on the target internal resistance, and to determine the SOH of the battery module based on the internal resistance growth rate of the target cell at the current moment and a preset mapping relationship. The preset mapping relationship is created by a relationship creation module, which is used to create a mapping relationship between the internal resistance growth rate and SOH of the target cell based on the experimental operation data of the target test cell and the historical operation data of the target cell. The target test cell is a cell of the same type as the target cell.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of a battery module SOH detection method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a method for detecting SOH in a battery module as described in any one of claims 1 to 7.

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