Battery internal short circuit detection methods, apparatus, equipment, storage media, and program products

Abstract

This application relates to a method, apparatus, device, storage medium, and program product for detecting internal short circuits in a battery. The method includes: determining the intermediate phase transition time of each cell in the battery under test during each operating cycle based on the electrical parameters of each cell under multiple operating cycles; obtaining the capacity change of each cell from the start of the corresponding operating cycle to the intermediate phase transition time, obtaining at least two capacity change values ​​for each cell; and determining the internal short circuit electrical parameters of each cell based on the at least two capacity change values, so as to determine the internal short circuit detection result of the battery under test based on the internal short circuit electrical parameters of each cell. In the above method, the electrical parameters of the cells in practical application scenarios are applicable to internal short circuit detection, thus reducing the scenario limitations for internal short circuit detection in batteries and improving the coverage and applicability of the detection scenarios.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, and in particular to a method, apparatus, device, storage medium, and program product for detecting internal short circuits in a battery. Background Technology

[0002] An internal short circuit in a battery refers to a short circuit that occurs when the positive and negative terminals are directly connected within the battery via the electrolyte. Internal short circuits not only affect battery performance but can also cause safety issues, such as thermal runaway. Therefore, internal short circuit testing is a crucial procedure for batteries.

[0003] In related technologies, it is usually necessary to obtain the battery's electrical parameters when the battery is charged to or near full charge in order to determine whether there is a risk of internal short circuit.

[0004] However, the relevant technologies have significant limitations in detecting short circuits within batteries, reducing their applicability to various scenarios. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, apparatus, device, storage medium, and program product for detecting short circuits inside a battery, in order to address the aforementioned technical problems.

[0006] In a first aspect, embodiments of this application provide a method for detecting short circuits within a battery, the method comprising:

[0007] Based on the electrical parameters of each cell in the battery under test during at least two operating cycles, determine the intermediate phase transition time of the corresponding voltage plateau period of each cell in each operating cycle.

[0008] Obtain the capacity change of each cell from the start of the corresponding working cycle to the intermediate phase transition moment, and obtain at least two capacity change values ​​for each cell.

[0009] Determine the internal short-circuit electrical parameters of each cell based on at least two capacity changes of each cell.

[0010] The internal short-circuit test results of the battery under test are determined based on the internal short-circuit electrical parameters of each cell.

[0011] In this embodiment, the intermediate phase transition time of the voltage plateau period of the battery cell is determined based on the electrical parameters of the battery cell in the corresponding working cycle. The internal short-circuit electrical parameters of the battery cell are determined by obtaining the capacity change of the battery cell from the beginning of the working cycle to the intermediate phase transition time, so as to realize the internal short-circuit detection of the battery under test. The voltage plateau period usually occurs when the battery cell's SOC reaches the intermediate state range. This intermediate state range matches the normal SOC range of the battery cell in the actual application scenario, so that the electrical parameters of the battery cell in the actual application scenario are suitable for internal short-circuit detection. Therefore, the scenario limitation for battery internal short-circuit detection is reduced, and the coverage and applicability of the detection scenario are improved.

[0012] In one embodiment, based on the electrical parameters of each cell in the battery under test over at least two operating cycles, the intermediate phase transition time of the corresponding voltage plateau period of each cell in each operating cycle is determined, including:

[0013] For each working cycle of each cell, the characteristic voltage sequence of the cell is determined based on the voltage sequence of the cell in the working cycle;

[0014] The intermediate phase transition time of the battery cell is determined based on the characteristic voltage sequence of the battery cell.

[0015] In this embodiment, a characteristic voltage sequence is determined by the voltage sequence of the battery cell, and the intermediate phase transition time is determined based on the characteristic voltage sequence. The intermediate phase transition time is determined by utilizing the correlation between the battery cell voltage, the characteristic voltage, and the reference phase transition characteristics, which improves the convenience and efficiency of determining the intermediate phase transition time.

[0016] In one embodiment, determining the characteristic voltage sequence of the battery cell based on the voltage sequence of the cell during the operating cycle includes:

[0017] When the battery under test is in a multi-stage stepped current charging state, the equivalent analog voltage sequence of the cell under constant analog current is determined based on the cell's voltage sequence and current sequence, and used as the characteristic voltage sequence of the cell.

[0018] When the battery under test is in other operating states, the open-circuit voltage sequence of the cell is determined based on the voltage sequence and current sequence of the cell, and used as the characteristic voltage sequence of the cell.

[0019] In this embodiment, different methods are used to determine the characteristic voltage sequence of the battery cell for different operating states of the battery under test, which improves the adaptability of the determination method to different operating states of the battery and correspondingly improves the reliability of the obtained characteristic voltage sequence of the battery cell.

[0020] In one embodiment, determining the intermediate phase transition time of the battery cell based on its characteristic voltage sequence includes:

[0021] The voltage-capacity curve of the battery cell is determined based on its characteristic voltage sequence; the voltage-capacity curve is used to characterize the relationship between characteristic voltage and capacity change.

[0022] The intermediate phase transition time is determined based on the cell's voltage-capacity curve and the reference voltage-capacity curve.

[0023] In this embodiment, the voltage-capacity curve of the battery cell can more intuitively and accurately reflect the state of charge of the battery, so as to accurately determine the intermediate phase transition time, thus improving the accuracy of determining the intermediate phase transition time.

[0024] In one embodiment, determining the voltage-capacity curve of the battery cell based on its characteristic voltage sequence includes:

[0025] Obtain the sequence of capacity changes of the battery cell corresponding to the characteristic voltage sequence time series of the battery cell;

[0026] Voltage-capacity curves are constructed based on the characteristic voltage sequence and the capacity change sequence.

[0027] In this embodiment, a voltage-capacity curve characterizing the relationship between characteristic voltage and capacity change is constructed based on the characteristic voltage sequence and capacity change sequence of the battery cell. This enables data visualization and more intuitively displays the relationship between characteristic voltage and capacity change during the battery cell's operation. The relationship between characteristic voltage and capacity change can accurately reflect the voltage plateau period during the battery cell's operation. Therefore, this voltage-capacity curve helps improve the convenience and reliability of determining the intermediate phase transition moment.

[0028] In one embodiment, the reference voltage-capacity curve includes a preset characteristic curve; determining the intermediate phase transition time based on the cell's voltage-capacity curve and the reference voltage-capacity curve includes:

[0029] The voltage-capacity curve is matched with a preset characteristic curve to obtain the range of capacity change in the curve matching region;

[0030] Determine the intermediate phase transition time within the time range corresponding to the capacity change.

[0031] In this embodiment, the voltage-capacity curve of the battery cell is directly matched with a preset characteristic curve, and the intermediate phase transition time is determined based on the curve matching region. The curve matching process is simple and easy to implement, which simplifies the process of determining the intermediate phase transition time and improves the efficiency of determining the intermediate phase transition time.

[0032] In one embodiment, determining the intermediate phase transition time based on the cell's voltage-capacity curve and a reference voltage-capacity curve includes:

[0033] Determine the reference voltage-capacity curve based on the voltage-capacity curve of each cell in the battery under test;

[0034] Obtain the capacity difference curve between the cell's voltage-capacity curve and the reference voltage-capacity curve;

[0035] The moment corresponding to the maximum peak point in the capacity difference curve is taken as the intermediate phase transition moment.

[0036] In this embodiment, the reference voltage-capacity curve is obtained based on the voltage-capacity curves of each cell in the battery under test. The intermediate phase transition time is determined by the capacity difference curve between the cell's voltage-capacity curve and the reference voltage-capacity curve, which improves the convenience and accuracy of determining the intermediate phase transition time.

[0037] In one embodiment, the internal short-circuit electrical parameters of each cell are determined based on at least two capacity variations of each cell, including:

[0038] For each capacity change of each cell, the capacity deviation between the capacity change and the reference capacity change is obtained; the reference capacity change is the average capacity change of all cells in the tested battery at the same time sequence as the capacity change.

[0039] The internal short-circuit electrical parameters of the cell are determined based on at least two capacity deviations.

[0040] In this embodiment, for each capacity change of each cell, the capacity deviation between the capacity change and the reference capacity change is obtained, so as to use multiple capacity deviations of the cell to reflect the changing trend of capacity deviation over time. The changing trend of capacity deviation can accurately characterize the internal short-circuit electrical parameters of the cell, thus improving the reliability of determining the internal short-circuit electrical parameters.

[0041] In one embodiment, determining the internal short-circuit electrical parameters of the cell based on at least two capacity deviations includes:

[0042] The slope of the fitted line is obtained by performing a linear fit based on at least two capacity deviations.

[0043] The internal short-circuit current and / or internal short-circuit resistance of the battery cell are determined based on the slope of the fitted straight line, and are used as the internal short-circuit electrical parameters of the battery cell.

[0044] In this embodiment, the slope of the fitted line formed by at least two capacity deviations is determined by linear fitting. The slope is used to characterize the changing trend of the capacity deviation of the battery cell, and the changing trend of the capacity deviation of the battery cell is the internal short-circuit current of the battery cell. The linear fitting algorithm is convenient and reliable, which can improve the efficiency and accuracy of determining the internal short-circuit electrical parameters of the battery cell.

[0045] In one embodiment, the internal short-circuit electrical parameters include internal short-circuit current and / or internal short-circuit resistance; based on the internal short-circuit electrical parameters of each cell, the internal short-circuit detection result of the battery under test is determined, including:

[0046] If the internal short-circuit electrical parameters of at least one cell in the battery under test meet the internal short-circuit conditions, the internal short-circuit test result of the battery under test is determined to have an internal short-circuit risk.

[0047] Internal short-circuit conditions include at least one of the following:

[0048] The internal short-circuit current exceeds the preset current threshold.

[0049] The internal short-circuit resistance is less than the preset resistance threshold.

[0050] In this embodiment, the internal short-circuit electrical parameters of each cell in the battery under test are directly determined based on the short-circuit condition to determine whether the internal short-circuit condition is met, thereby obtaining the internal short-circuit detection result of whether the battery under test has an internal short-circuit risk. This simplifies the determination process of the internal short-circuit detection result of the battery under test and improves the determination efficiency.

[0051] Secondly, embodiments of this application also provide a battery internal short circuit detection device, the device comprising:

[0052] The timing determination module is used to determine the intermediate phase transition time of the corresponding voltage plateau period of each cell in the battery under test based on the electrical parameters of each cell in at least two working cycles.

[0053] The capacity acquisition module is used to acquire the capacity change of each cell from the start of the corresponding working cycle to the intermediate phase transition moment, and obtain at least two capacity change values ​​for each cell.

[0054] The parameter determination module is used to determine the internal short-circuit electrical parameters of each cell based on at least two capacity changes of each cell.

[0055] The test result module is used to determine the internal short-circuit test result of the battery under test based on the internal short-circuit electrical parameters of each cell.

[0056] Thirdly, embodiments of this application also provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the battery internal short circuit detection method provided in any of the embodiments of the first aspect above.

[0057] Fourthly, embodiments of this application also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps in the battery internal short circuit detection provided in any of the embodiments of the first aspect above.

[0058] Fifthly, embodiments of this application also provide a computer program product, including a computer program that, when executed by a processor, implements the steps in battery short-circuit detection provided in any of the embodiments of the first aspect described above.

[0059] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0060] Figure 1 This is an internal structural diagram of a computer device in one embodiment;

[0061] Figure 2 This is a flowchart illustrating a short-circuit detection method within a battery in one embodiment;

[0062] Figure 3 This is a schematic diagram illustrating the relationship between the open-circuit voltage and the state of charge of a battery cell in one embodiment.

[0063] Figure 4 This is a flowchart illustrating the process of determining the intermediate phase transition moment in one embodiment;

[0064] Figure 5 This is a flowchart illustrating the process of determining a characteristic voltage sequence in one embodiment;

[0065] Figure 6 This is a flowchart illustrating the process of determining the intermediate phase transition moment in another embodiment;

[0066] Figure 7 This is a schematic diagram of the process for constructing a voltage-capacity curve in one embodiment;

[0067] Figure 8 This is a flowchart illustrating the process of determining the intermediate phase transition moment in another embodiment;

[0068] Figure 9 This is a schematic diagram of the voltage-capacity curve of a battery cell in one embodiment;

[0069] Figure 10 This is a flowchart illustrating the process of determining the intermediate phase transition moment in another embodiment;

[0070] Figure 11 This is a flowchart illustrating the process of determining internal short-circuit electrical parameters in one embodiment;

[0071] Figure 12 This is a flowchart illustrating the process of determining internal short-circuit electrical parameters in another embodiment;

[0072] Figure 13This is a schematic diagram showing the distribution of charge-discharge test data in one embodiment;

[0073] Figure 14 This is a structural block diagram of a battery internal short circuit detection device in one embodiment. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0075] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the term "comprising" and any variations thereof in the specification, claims and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0076] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0077] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), unless otherwise explicitly specified.

[0078] An internal short circuit in a battery refers to a short circuit that occurs when the positive and negative terminals are directly connected within the battery via the electrolyte. Internal short circuits not only affect battery performance but can also cause safety issues, such as thermal runaway. Therefore, internal short circuit testing is a crucial procedure for batteries.

[0079] In related technologies, it is usually necessary to obtain the battery's electrical parameters when it is charged to or near full charge to determine whether there is a risk of internal short circuit. In practical applications, the battery's normal state of charge (SOC) usually does not reach the full charge state of more than 90%, and is generally between 30% and 90%.

[0080] This makes it impossible for the relevant technologies to cover the normal operating scenarios of batteries, increasing the limitations of short circuit detection within batteries, reducing scenario coverage, and thus reducing scenario applicability.

[0081] In one embodiment, a battery internal short circuit detection method is provided, which is applied to... Figure 1 The following description uses a computing device as an example. This computer device includes a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for detecting short circuits within a battery.

[0082] It should be noted that the computer equipment can be a testing device independent of the battery under test, or it can be a control device belonging to the same electrical equipment / energy storage system as the battery under test.

[0083] Those skilled in the art will understand that Figure 1 The structures shown are merely block diagrams of some structures related to the embodiments of this application and do not constitute a limitation on the computer devices on which the embodiments of this application are applied. Specific computer devices may include more or fewer components than those shown in the figures, or combine certain components, or have different component arrangements.

[0084] In one embodiment, this application provides a method for detecting short circuits within a battery, such as... Figure 2 As shown, this embodiment includes the following steps:

[0085] S210. Based on the electrical parameters of each cell in the battery under test under at least two working cycles, determine the intermediate phase transition time of the corresponding voltage plateau period of each cell in each working cycle.

[0086] The battery under test may include multiple cells, which may be connected in series. For example, the battery under test is a lithium battery, such as a lithium iron phosphate battery.

[0087] The working cycle of the battery under test can be either the working cycle corresponding to the charging process or the working cycle corresponding to the discharging process. Accordingly, the electrical parameters include the charging current and / or cell voltage of the cell during the charging process, or the discharging current and / or cell voltage of the cell during the discharging process.

[0088] Each charging / discharging cycle performed by the battery under test is considered one working cycle. At least two working cycles must correspond to the same working process, such as both being working cycles corresponding to charging processes, or both being working cycles corresponding to discharging processes.

[0089] It should be noted that the voltage plateau period refers to the stage during which the open circuit voltage (OCV) of a battery cell changes slowly and is relatively stable during the charging or discharging process. It usually occurs when the cell's state of charge (SOC) reaches an intermediate range (e.g., 50%~60%). The intermediate phase transition moment can be any moment within the voltage plateau period. Figure 3 The example demonstrates the relationship between OCV and SOC during the charging process of a battery cell. It can be seen that in the early stage (a) and the late stage (c) of charging, OCV shows a clear trend with the change of SOC, while in the middle stage (b) of charging, OCV shows a relatively flat trend with the change of SOC. The middle stage (b) of charging corresponds to the voltage plateau period of the battery cell.

[0090] Optionally, the computer equipment can acquire the electrical parameters of each cell in the battery under test under at least two operating cycles. For each cell, based on the electrical parameters under each operating cycle, it can determine whether the cell has experienced a voltage plateau period within the corresponding operating cycle. For example, based on the cell's operating current and cell voltage in the corresponding operating cycle, the open-circuit voltage of the cell over time can be determined. If the change in open-circuit voltage is less than a preset range after a preset time, then the cell has experienced a voltage plateau period in that operating cycle; otherwise, it has not. If a voltage plateau period is determined to have occurred, the computer equipment can determine the intermediate phase transition time based on the voltage plateau period, such as selecting the start time of the voltage plateau period as the intermediate phase transition time.

[0091] For example, when acquiring the electrical parameters of a battery cell, the computer device can acquire the electrical parameters of each cell online during the operation of the battery under test for at least two operating cycles, or it can acquire the electrical parameters of each cell for at least two operating cycles from the historical operating information of the battery under test. The computer can also instruct a charging device to charge the battery under test multiple times to acquire the electrical parameters of each cell in the battery under test for at least two operating cycles corresponding to the charging process, or instruct the battery under test to discharge the device multiple times to acquire the electrical parameters of each cell in the battery under test for at least two operating cycles corresponding to the discharging process.

[0092] S220. Obtain the capacity change of each cell from the start of the corresponding working cycle to the intermediate phase transition moment, and obtain at least two capacity change values ​​for each cell.

[0093] Optionally, for each working cycle, the computer device can acquire the cell's operating current (charging current or discharging current) from the start of the working cycle to the corresponding intermediate phase transition moment, and integrate the current with time to obtain the capacity change of the cell from the start of the working cycle to the intermediate phase transition moment. For each cell, at least two capacity changes can be obtained correspondingly over at least two working cycles.

[0094] S230. Determine the internal short-circuit electrical parameters of each cell based on at least two capacity changes of each cell.

[0095] The internal short-circuit electrical parameters of the battery cell are used to evaluate the internal short-circuit state of the cell. For example, the internal short-circuit electrical parameters of the battery cell include the internal short-circuit current and / or internal short-circuit resistance.

[0096] Optionally, for each cell, the computer device can determine the internal short-circuit electrical parameters of the cell based on at least two capacity variations of the cell.

[0097] For example, a computer device can input at least two capacity changes of a battery cell into a pre-trained internal short-circuit detection model, and output the internal short-circuit electrical parameters of the battery cell, such as the internal short-circuit current of the battery cell, through the internal short-circuit detection model. The internal short-circuit detection model is a deep learning model, such as a Convolutional Neural Network (CNN) model, trained using a large number of capacity changes of battery cells and the standard internal short-circuit current of the battery cell as training samples.

[0098] S240. Determine the internal short-circuit test result of the battery under test based on the internal short-circuit electrical parameters of each cell.

[0099] Optionally, after obtaining the internal short-circuit electrical parameters of each cell of the battery under test, the internal short-circuit test result of each cell can be determined based on the internal short-circuit electrical parameters of each cell, and the internal short-circuit test results of each cell can be summarized as the internal short-circuit test result of the battery under test.

[0100] For example, the internal short-circuit detection result of the battery cell is used to characterize whether the battery cell has an internal short-circuit risk. When the internal short-circuit electrical parameters include the internal short-circuit current, for each battery cell, the computer device can compare the internal short-circuit current of the battery cell with a preset current threshold. If the internal short-circuit current of the battery cell is greater than the preset current threshold, it is determined that the battery cell has an internal short-circuit risk; conversely, if the internal short-circuit current of the battery cell is less than or equal to the preset current threshold, it is determined that the battery cell does not have an internal short-circuit risk.

[0101] Optionally, if the internal short-circuit test results of the battery under test indicate that at least one cell in the battery under test has an internal short-circuit risk, the computer device can generate an internal short-circuit risk alarm to issue an internal short-circuit risk alarm. For example, the computer device can determine the identifier (such as the cell number) of the cell with an internal short-circuit risk, generate an internal short-circuit risk alarm including the identifier, and display the internal short-circuit risk alarm through a display unit or feed it back to other external devices.

[0102] In this embodiment, based on the electrical parameters of each cell in the battery under test under multiple operating cycles, the intermediate phase transition time of the cell corresponding to the voltage plateau period in each operating cycle is determined. The capacity change of each cell from the start of the corresponding operating cycle to the intermediate phase transition time is obtained, resulting in at least two capacity change values ​​for each cell. Based on these at least two capacity change values, the internal short-circuit electrical parameters of each cell are determined, and the internal short-circuit detection result of the battery under test is determined based on these internal short-circuit electrical parameters. In the above method, the cell's electrical parameters in the corresponding operating cycle are used to determine the cell's internal short-circuit detection result. The internal short-circuit electrical parameters of the cell are determined by measuring the capacity change from the start of the operating cycle to the intermediate phase transition time corresponding to the voltage plateau period. This enables internal short-circuit detection of the battery under test. The voltage plateau period typically occurs when the cell's state of charge (SOC) reaches an intermediate range. This intermediate range matches the normal SOC range of the cell in actual application scenarios, making the electrical parameters of the cell suitable for internal short-circuit detection in practical applications. Therefore, it reduces the limitations of battery internal short-circuit detection scenarios and improves the coverage and applicability of detection scenarios.

[0103] To determine the intermediate phase transition moment of the battery cell, in one embodiment, such as Figure 4 As shown, S210 above, based on the electrical parameters of each cell in the battery under test under at least two operating cycles, determines the intermediate phase transition time of the corresponding voltage plateau period of each cell in each operating cycle, including:

[0104] S410. For each working cycle of each cell, determine the characteristic voltage sequence of the cell based on the voltage sequence of the cell in the working cycle.

[0105] The cell voltage sequence represents the cell voltage as it changes over time during cell operation. The cell characteristic voltage sequence represents the characteristic voltage as it changes over time during cell operation; this characteristic voltage is determined based on the cell voltage at the corresponding time sequence in the voltage sequence.

[0106] Optionally, the electrical parameters of each cell in the battery under test obtained by the computer device in multiple working cycles include the voltage sequence of each cell in the corresponding working cycle. For each working cycle of each cell, the computer device can convert the voltage of each cell in the voltage sequence into a characteristic voltage according to the conversion relationship between cell voltage and characteristic voltage, so as to obtain a characteristic voltage sequence corresponding to the voltage sequence timing.

[0107] S420. Determine the intermediate phase transition time of the battery cell based on the characteristic voltage sequence of the battery cell.

[0108] Optionally, after obtaining the characteristic voltage sequence of each cell in the battery under test, the computer equipment can perform data analysis on the characteristic voltage sequence of the cells to determine the intermediate phase transition time of the cells.

[0109] For example, a computer device can acquire the difference between time-adjacent characteristic voltages in a characteristic voltage sequence, determine a range of characteristic voltages in the characteristic voltage sequence whose absolute value of the difference is less than a preset difference and whose time sequence is continuous, and determine the intermediate phase transition time based on the characteristic voltage range. For example, the time corresponding to the first characteristic voltage, the last characteristic voltage, and the intermediate characteristic voltage in the characteristic voltage range can be acquired as the intermediate phase transition time.

[0110] In this embodiment, for each working cycle of each cell, the characteristic voltage sequence of the cell is determined based on the voltage sequence of the cell in the working cycle, and then the intermediate phase transition time of the cell is determined based on the characteristic voltage sequence of the cell. In the above method, the characteristic voltage sequence is determined by the voltage sequence of the cell, and the intermediate phase transition time is determined based on the characteristic voltage sequence. The intermediate phase transition time is determined by utilizing the correlation between the cell voltage, the characteristic voltage, and the reference phase transition characteristics, which improves the convenience and efficiency of determining the intermediate phase transition time.

[0111] The method for determining the characteristic voltage sequence of the battery under test differs depending on its operating state. Based on this, in one embodiment, such as... Figure 5 As shown, in S410 above, determining the characteristic voltage sequence of the battery cell based on the voltage sequence of the battery cell during the operating cycle includes:

[0112] S510. When the battery under test is in the working state of multi-stage stepped current charging, determine the equivalent analog voltage sequence of the battery cell under constant analog current based on the voltage sequence and current sequence of the battery cell, and use it as the characteristic voltage sequence of the battery cell.

[0113] Multi-stage stepped current charging refers to a charging mode in which the charging current gradually increases or decreases according to a predetermined series of stepped stages, typically corresponding to fast charging mode. The cell's current sequence represents the operating current of the battery under test as it changes over time. This operating current corresponds to the charging current during the charging process and the discharging current during the discharging process.

[0114] The constant analog current is the preset charging current. The timing correspondence between the cell's voltage sequence, current sequence, and equivalent analog voltage sequence is as follows: a cell voltage in the voltage sequence corresponds to a charging current in the current sequence, and similarly, corresponds to an equivalent analog voltage in the equivalent analog voltage sequence.

[0115] Optionally, the computer device can identify the direction and changes of the cell's operating current, so that when the charging current is found to be changing in a stepwise manner, it can determine that the battery under test is in a multi-stage stepwise current charging state. Based on the cell voltage before and after the change in the cell's voltage sequence and the charging current before and after the change in the cell's current sequence, it can determine the equivalent analog voltage sequence of the cell under constant analog current as the characteristic voltage sequence of the cell.

[0116] For example, the computer device can acquire the voltage sequence and current sequence of the battery cell during the corresponding working cycle of the charging process. When it is detected that the charging current changes in a stepwise manner, the charging current before and after the change in the current sequence and the battery cell voltage before and after the change in the voltage sequence are input into a preset battery model to calibrate the model parameters. Then, the calibrated model parameters are substituted into the preset battery model, and a constant analog current is input into the preset battery model. The preset battery model outputs the equivalent analog voltage sequence of the battery cell under constant analog current, so as to convert the charging current and battery cell voltage under the variable current scenario into the charging current and battery cell voltage under the constant current scenario.

[0117] S520. When the battery under test is in other working states, determine the open-circuit voltage sequence of the battery cell based on the voltage sequence and current sequence of the battery cell, and use it as the characteristic voltage sequence of the battery cell.

[0118] Other operating states refer to operating states other than the multi-stage stepped current charging mentioned above, such as discharging, constant current charging (usually corresponding to slow charging mode), or charging and discharging with arbitrary variable current (for applications in frequency modulation and peak shaving scenarios).

[0119] Optionally, the computer equipment can identify the direction and changes of the cell's operating current, so that when the battery under test is identified to be in an operating state other than multi-stage stepped current charging, the computer equipment can determine the open-circuit voltage of the corresponding time sequence based on the cell voltage and operating current of the same time sequence in the cell's voltage sequence and current sequence, and obtain the open-circuit voltage sequence as the characteristic voltage sequence of the cell.

[0120] For example, a computer device can input the cell voltage and operating current of the same timing sequence into the equivalent circuit model of the cell to identify the model parameters and obtain the open-circuit voltage of the corresponding timing sequence.

[0121] In this embodiment, when the battery under test is in a multi-stage stepped current charging state, the equivalent analog voltage sequence of the battery cell under constant analog current is determined based on the voltage sequence and current sequence of the battery cell, and is used as the characteristic voltage sequence of the battery cell; when the battery under test is in other operating states, the open circuit voltage sequence of the battery cell is determined based on the voltage sequence and current sequence of the battery cell, and is used as the characteristic voltage sequence of the battery cell; in the above method, different methods are used to determine the characteristic voltage sequence of the battery cell for different operating states of the battery under test, which improves the adaptability of the determination method to different operating states of the battery, and correspondingly improves the reliability of the obtained characteristic voltage sequence of the battery cell.

[0122] The intermediate phase transition moment of a battery cell can be determined based on a voltage-capacity curve characterizing the relationship between the cell's characteristic voltage and capacity change. Based on this, in one embodiment, such as... Figure 6 As shown, S420 above, determining the intermediate phase transition time of the battery cell based on the characteristic voltage sequence of the battery cell, includes:

[0123] S610. Determine the voltage-capacity curve of the battery cell based on the characteristic voltage sequence of the battery cell; the voltage-capacity curve is used to characterize the relationship between the characteristic voltage and the change in capacity.

[0124] The relationship between the characteristic voltage and capacity change of the battery cell follows the same trend as the relationship between the open-circuit voltage and state of charge of the battery cell.

[0125] Optionally, after obtaining the characteristic voltage sequence of the battery cell, the computer device can acquire the operating current of the battery cell corresponding to each characteristic voltage time sequence in the characteristic voltage sequence, integrate the current and time for the operating current at each moment, determine the capacity change corresponding to the characteristic voltage at each moment in the characteristic voltage sequence, and obtain a voltage-capacity curve characterizing the relationship between the characteristic voltage and the capacity change.

[0126] S620. Determine the intermediate phase transition time based on the cell's voltage-capacity curve and the reference voltage-capacity curve.

[0127] Optionally, the computer equipment can analyze and process the voltage-capacity curve of the battery cell and the reference voltage-capacity curve to obtain the intermediate phase transition time of the battery cell.

[0128] For example, a computer device can construct a voltage-capacity curve of a battery cell based on the cell's voltage-capacity curve and a reference voltage-capacity curve, and use incremental capacity analysis (ICA) or differential voltage analysis (DVA) algorithms to determine the intermediate phase transition time of the battery cell.

[0129] In this embodiment, the voltage-capacity curve of the battery cell is determined based on the characteristic voltage sequence of the battery cell, and the intermediate phase transition time is determined based on the voltage-capacity curve of the battery cell and the reference voltage-capacity curve. The voltage-capacity curve is used to characterize the relationship between the characteristic voltage and the capacity change. In the above method, the voltage-capacity curve of the battery cell can more intuitively and accurately reflect the state of charge of the battery, so as to accurately determine the intermediate phase transition time, thus improving the accuracy of determining the intermediate phase transition time.

[0130] In one embodiment, such as Figure 7 As shown, the above-mentioned S610, determining the voltage-capacity curve of the battery cell based on the characteristic voltage sequence of the battery cell, includes:

[0131] S710. Obtain the capacity change sequence of the battery cell corresponding to the characteristic voltage sequence timing of the battery cell.

[0132] Optionally, after obtaining the characteristic voltage sequence of the battery cell, the computer device can acquire the operating current of the battery cell corresponding to each characteristic voltage time sequence in the characteristic voltage sequence, integrate the current and time for the operating current at each moment, determine the capacity change corresponding to the characteristic voltage at each moment in the characteristic voltage sequence, and obtain the capacity change sequence of the battery cell corresponding to the characteristic voltage sequence time sequence of the battery cell.

[0133] S720. Construct voltage-capacity curves based on the characteristic voltage sequence and capacity change sequence.

[0134] Optionally, after obtaining the characteristic voltage sequence and capacity change sequence corresponding to the battery cell timing, the computer device can use the characteristic voltage as the vertical axis and the capacity change as the horizontal axis to construct a voltage-capacity curve that characterizes the relationship between the characteristic voltage and the capacity change of the battery cell.

[0135] In this embodiment, the capacity change sequence of the battery cell corresponding to the characteristic voltage sequence of the battery cell is obtained, and a voltage-capacity curve is constructed based on the characteristic voltage sequence and the capacity change sequence. In the above method, a voltage-capacity curve representing the relationship between the characteristic voltage and the capacity change is constructed based on the characteristic voltage sequence and the capacity change sequence of the battery cell. This achieves data visualization processing and more intuitively shows the relationship between the characteristic voltage and the capacity change during the operation of the battery cell. The relationship between the characteristic voltage and the capacity change can accurately reflect the voltage plateau period during the operation of the battery cell. Therefore, based on this voltage-capacity curve, it helps to improve the convenience and reliability of determining the intermediate phase transition moment.

[0136] In one embodiment, where the reference voltage-capacity curve includes a preset characteristic curve, such as Figure 8As shown, the above-mentioned S620, determining the intermediate phase transition time based on the cell's voltage-capacity curve and the reference voltage-capacity curve, includes:

[0137] S810. Match the voltage-capacity curve with the preset characteristic curve to obtain the range of capacity change in the curve matching area.

[0138] The preset characteristic curve is a preset curve used to characterize the relationship between the characteristic voltage and capacity change during the voltage plateau period, including the intermediate phase transition moment, of the corresponding battery cell. The curve matching region is the curve region in the voltage-capacity curve that matches at least a portion of the preset characteristic curve. For example, the preset characteristic curve is... Figure 3 Curve S in the diagram.

[0139] Optionally, the computer device can read a pre-stored preset characteristic curve and match the voltage-capacity curve of the battery cell with the preset characteristic curve to obtain a curve matching region in the voltage-capacity curve that matches at least part of the preset characteristic curve, and obtain the capacity change amount corresponding to the start position and the end position in the voltage-capacity curve of the battery cell, respectively, to form a capacity change range from the capacity change amount at the start position to the capacity change amount at the end position.

[0140] For example, such as Figure 9 As shown, the computer device matches the voltage-capacity curve Sa of cell a with the preset characteristic curve S to obtain the curve matching region Sa', and obtains the capacity variation range [C1, C2] of the curve matching region Sa' in the voltage-capacity curve Sa.

[0141] S820. Determine the intermediate phase transition time within the time range corresponding to the capacity change.

[0142] Optionally, after obtaining the range of capacity change in the curve matching region, the computer device can determine the intermediate phase transition time within the time corresponding to the range of capacity change.

[0143] For example, the computer device can select any moment corresponding to the range of capacity changes as the intermediate phase transition moment of the battery cell, such as the earliest moment, the latest moment, or the intermediate moment corresponding to the range of capacity changes. (Continue) Figure 9 For example, the time corresponding to C1 (i.e., the earliest time) can be selected as the intermediate phase transition time of the cell, or the time corresponding to C2 (i.e., the latest time) can be selected as the intermediate phase transition time of the cell.

[0144] It should be noted that when determining the intermediate phase transition time based on the range of capacity change, a unified standard should be applied to each cell in the battery under test. For example, the earliest time corresponding to the range of capacity change should be selected as the intermediate phase transition time, or the earliest time corresponding to the range of capacity change should be selected as the intermediate phase transition time.

[0145] In this embodiment, the reference voltage-capacity curve includes a preset characteristic curve. By matching the voltage-capacity curve with the preset characteristic curve, the range of capacity change in the curve matching region is obtained, so as to determine the intermediate phase transition time at the time corresponding to the range of capacity change. In the above method, the voltage-capacity curve of the cell is directly matched with the preset characteristic curve, and the intermediate phase transition time is determined based on the curve matching region. The curve matching process is simple and easy to implement, which simplifies the process of determining the intermediate phase transition time and improves the efficiency of determining the intermediate phase transition time.

[0146] A reference voltage-capacity curve can be determined based on the voltage-capacity curves of each cell in the battery under test. Based on this, in one embodiment, such as... Figure 10 As shown, the above-mentioned S620, determining the intermediate phase transition time based on the cell's voltage-capacity curve and the reference voltage-capacity curve, includes:

[0147] S1010. Determine the reference voltage-capacity curve based on the voltage-capacity curves of each cell in the battery under test.

[0148] Optionally, after obtaining the voltage-capacity curves of each cell in the battery under test, the computer equipment can perform average processing on the voltage-capacity curves of all cells to obtain a reference voltage-capacity curve, or it can select the voltage-capacity curve of any cell as the reference voltage-capacity curve.

[0149] For example, the battery under test includes cell 1 and cell 2. The computer device can obtain the voltage-capacity curve S1 of cell 1 and the voltage-capacity curve S2 of cell 2 under one working cycle. The horizontal axis (i.e., capacity change) of voltage-capacity curves S1 and S2 is the same. The computer device can obtain the average value of the vertical axis (i.e., characteristic voltage) corresponding to the same horizontal axis between voltage-capacity curves S1 and S2, and obtain all the average values ​​as a reference voltage-capacity curve with a new vertical axis.

[0150] S1020. Obtain the capacity difference curve between the cell's voltage-capacity curve and the reference voltage-capacity curve.

[0151] Optionally, the computer device subtracts the value of the vertical axis of the cell's voltage-capacity curve from the reference voltage-capacity curve, i.e., the change in capacity, to obtain the capacity difference curve between the voltage-capacity curve and the reference voltage-capacity curve.

[0152] S1030. Obtain the maximum peak point in the capacity difference curve as the intermediate phase transition moment.

[0153] Among them, the capacity difference curve generally shows a trend of first increasing and then decreasing.

[0154] Optionally, after obtaining the capacity difference curve of the battery cell, the computer device can identify the maximum peak point in the capacity difference curve and obtain the time corresponding to the maximum peak point as the intermediate phase transition time of the battery cell.

[0155] In this embodiment, a reference voltage-capacity curve is determined based on the voltage-capacity curves of each cell in the battery under test. The capacity difference curve between the cell's voltage-capacity curve and the reference voltage-capacity curve is obtained, and the moment corresponding to the maximum peak point in the capacity difference curve is obtained as the intermediate phase transition moment. In the above method, the reference voltage-capacity curve is obtained based on the voltage-capacity curves of each cell in the battery under test. The intermediate phase transition moment is determined by using the capacity difference curve between the cell's voltage-capacity curve and the reference voltage-capacity curve, which improves the convenience and accuracy of determining the intermediate phase transition moment.

[0156] To obtain the internal short-circuit electrical parameters of the battery cell, in one embodiment, such as Figure 11 As shown, in S230 above, based on at least two capacity changes of each cell, the internal short-circuit electrical parameters of each cell are determined, including:

[0157] S1110. For each capacity change of each cell, obtain the capacity deviation between the capacity change and the reference capacity change; the reference capacity change is the average capacity change of all cells in the battery under test in the same time sequence as the capacity change.

[0158] The reference capacity change can also be any one of the capacity changes of all cells in the battery under test in the same time sequence as the capacity change.

[0159] Optionally, after obtaining at least two capacity changes for each cell in the battery under test, the computer equipment can acquire the average capacity change of all cells in the battery under test over the same time period. For each capacity change of each cell, the computer equipment can acquire the capacity deviation between that capacity change and the average capacity change over the same time period. Based on the at least two capacity changes of each cell, at least two capacity deviations for each cell can be obtained accordingly.

[0160] For example, the battery under test includes N cells, each cell corresponding to K capacity changes, and the capacity change of each cell is represented as cap_cell_i_j (i=1,2,3,…,N; j=1,2,3,…,K). Taking a battery under test comprising 2 (N=2) cells (cell #1 and cell #2 respectively), each cell including 2 (K=2) capacity changes as an example:

[0161] For cell #1, the average of cap_cell_1_1 and cap_cell_2_1 is used as the reference capacity change, and the capacity deviation cap_diff_cell_1_1 between cap_cell_1_1 and the reference capacity change is obtained; for cell #1, the average of cap_cell_1_2 and cap_cell_2_2 is used as the reference capacity change, and the capacity deviation cap_diff_cell_1_2 between cap_cell_1_2 and the reference capacity change is obtained. For cap_cell_2_1 of cell #2, the average value of cap_cell_1_1 and cap_cell_2_1 is obtained as the reference capacity change, and the capacity deviation cap_diff_cell_2_1 between cap_cell_2_1 and the reference capacity change is obtained; for cap_cell_2_2 of cell #2, the average value of cap_cell_1_2 and cap_cell_2_2 is obtained as the reference capacity change, and the capacity deviation cap_diff_cell_2_2 between cap_cell_2_2 and the reference capacity change is obtained.

[0162] For example, taking cell #2 as an example, as shown in the table below, with K capacity changes included, K capacity deviations are obtained accordingly.

[0163]

[0164] S1120. Determine the internal short-circuit electrical parameters of the cell based on at least two capacity deviations.

[0165] Optionally, after obtaining at least two capacity deviations of the battery cell, the internal short-circuit electrical parameters of the corresponding battery cell can be determined based on the at least two capacity deviations.

[0166] For example, a computer device can input at least two capacity deviations of a battery cell into a pre-trained internal short-circuit detection model, and output the internal short-circuit electrical parameters of the battery cell, such as the internal short-circuit current of the battery cell, through the internal short-circuit detection model. The internal short-circuit detection model is a deep learning model, such as a CNN model, trained using a large number of battery cell capacity deviations and the standard internal short-circuit current of the battery cell as training samples.

[0167] In this embodiment, for each capacity change of each cell, the capacity deviation between the capacity change and a reference capacity change is obtained, and the internal short-circuit electrical parameters of the cell are determined based on at least two capacity deviations. The reference capacity change is the average capacity change of all cells in the battery under test at the same time sequence as the capacity change. In the above method, for each capacity change of each cell, the capacity deviation between the capacity change and the reference capacity change is obtained, so that the multiple capacity deviations of the cell can reflect the changing trend of the capacity deviation over time. The changing trend of the capacity deviation can accurately characterize the internal short-circuit electrical parameters of the cell, thus improving the reliability of determining the internal short-circuit electrical parameters.

[0168] The trend of cell capacity deviation over time can be used to determine the battery's internal short-circuit current. Based on this, in one embodiment, such as... Figure 12 As shown, the above-mentioned S1120, determining the internal short-circuit electrical parameters of the cell based on at least two capacity deviations, includes:

[0169] S1210. Perform linear fitting based on at least two capacity deviations to obtain the slope of the fitted line.

[0170] Optionally, the computer device can perform linear fitting on at least two capacity deviations of the battery cell to obtain the slope of the fitted straight line formed by fitting the at least two capacity deviations.

[0171] For example, a computer device can use a preset fitting algorithm to perform linear fitting on at least two capacity deviations of the battery cell, and obtain an expression characterizing the fitted straight line formed by the fitting of the at least two capacity deviations:

[0172] Y=k*X+b

[0173] In the formula, Y represents the capacity deviation of the battery cell, in As; X represents time, in seconds; and k represents the slope.

[0174] S1220. Determine the internal short-circuit current and / or internal short-circuit resistance of the battery cell based on the slope of the fitted straight line, as the internal short-circuit electrical parameters of the battery cell.

[0175] The slope of the fitted straight line described above is used to characterize the change trend of the cell's capacity deviation over time, corresponding to the cell's internal short-circuit current I. ISC That is, k=I ISC .

[0176] Optionally, after obtaining the slope of the fitted straight line, the computer equipment can use the slope as the internal short-circuit current of the battery cell and use the internal short-circuit current of the battery cell as the internal short-circuit electrical parameter of the battery cell. Alternatively, the internal short-circuit resistance of the battery cell can be further determined based on the internal short-circuit parameter of the battery cell and the internal short-circuit resistance of the battery cell can be used as the internal short-circuit electrical parameter of the battery cell. Or, the internal short-circuit current and internal short-circuit resistance of the battery cell can be used together as the internal short-circuit electrical parameter of the battery cell.

[0177] For example, after obtaining the internal short-circuit current of the battery cell, the computer device can determine the internal short-circuit resistance based on the historical voltage of the battery cell and the internal short-circuit circuit, such as according to the average historical voltage U of the battery cell. mean With internal short-circuit current I ISC The internal short-circuit resistance R of the battery cell was calculated. ISC U mean I ISC and R ISC The three satisfy the following relationship:

[0178]

[0179] When the internal short-circuit test results of the battery under test are determined based on the electrical parameters of each cell in the battery under test over at least two operating cycles, U mean The value of the cell voltage for the corresponding cell over at least two operating cycles is given by N, where N represents the number of cell voltages, and U... i This represents the voltage of the i-th cell.

[0180] In this embodiment, a linear fit is performed based on at least two capacity deviations to obtain the slope of the fitted line. The internal short-circuit current and / or internal short-circuit resistance of the cell are then determined based on the slope of the fitted line as the internal short-circuit electrical parameters of the cell. In the above method, the slope of the fitted line formed by at least two capacity deviations is determined by linear fitting. This slope is used to characterize the changing trend of the capacity deviation of the cell, and the changing trend of the capacity deviation of the cell is the internal short-circuit current of the cell. The linear fitting algorithm is convenient and reliable, which can improve the efficiency and accuracy of determining the internal short-circuit electrical parameters of the cell.

[0181] In one embodiment, when the internal short-circuit electrical parameters include internal short-circuit current and / or internal short-circuit resistance, S240 above, determining the internal short-circuit detection result of the battery under test based on the internal short-circuit electrical parameters of each cell, includes:

[0182] If the internal short-circuit electrical parameters of at least one cell in the battery under test meet the internal short-circuit conditions, the internal short-circuit test result of the battery under test is determined to have an internal short-circuit risk.

[0183] Internal short-circuit conditions include at least one of the following:

[0184] The internal short-circuit current exceeds the preset current threshold.

[0185] The internal short-circuit resistance is less than the preset resistance threshold.

[0186] Optionally, after obtaining the internal short-circuit electrical parameters of each cell, the computer equipment matches the internal short-circuit parameters of each cell with preset internal short-circuit conditions to determine whether the internal short-circuit electrical parameters of each cell meet the internal short-circuit conditions. If the internal short-circuit electrical parameters of at least one cell in the battery under test meet the internal short-circuit conditions, the internal short-circuit test result of the battery under test is determined to have an internal short-circuit risk; otherwise, if the internal short-circuit electrical parameters of all cells in the battery under test do not meet the internal short-circuit conditions, the internal short-circuit test result of the battery under test is determined to have no internal short-circuit risk.

[0187] For example, the internal short-circuit electrical parameters of the battery cell include internal short-circuit current and internal short-circuit resistance. The computer device can compare the internal short-circuit current with a preset current threshold and the internal short-circuit resistance with a preset resistance threshold. If the internal short-circuit current is greater than the preset current threshold, or the internal short-circuit resistance is less than the preset resistance threshold, then it is determined that the internal short-circuit electrical parameters of the battery cell meet the internal short-circuit condition; otherwise, if the internal short-circuit current is less than or equal to the preset current threshold and the internal short-circuit resistance is greater than or equal to the preset resistance threshold, then it is determined that the internal short-circuit electrical parameters of the battery cell do not meet the internal short-circuit condition.

[0188] In this embodiment, the internal short-circuit electrical parameters include internal short-circuit current and / or internal short-circuit resistance. If the internal short-circuit electrical parameters of at least one cell in the battery under test meet the internal short-circuit conditions, the internal short-circuit detection result of the battery under test is determined to indicate an internal short-circuit risk. The internal short-circuit conditions include at least one of the following: the internal short-circuit current is greater than a preset current threshold; the internal short-circuit resistance is less than a preset resistance threshold. In the above method, the internal short-circuit electrical parameters of each cell in the battery under test are directly determined based on the short-circuit conditions to determine whether the battery under test has an internal short-circuit risk, thereby obtaining the internal short-circuit detection result. This simplifies the determination process of the internal short-circuit detection result of the battery under test and improves the determination efficiency.

[0189] To facilitate understanding by those skilled in the art, the battery internal short circuit detection method provided in this application is described in detail below, such as... Figure 13 As shown, the method may include:

[0190] S1301. For each cell in the battery under test, obtain the voltage sequence and current sequence of the cell in at least two working cycles.

[0191] S1302. When the battery under test is in the working state of multi-stage stepped current charging, determine the equivalent analog voltage sequence of the battery cell under constant analog current based on the voltage sequence and current sequence of the battery cell, and use it as the characteristic voltage sequence of the battery cell.

[0192] S1303. When the battery under test is in other working states, determine the open-circuit voltage sequence of the battery cell based on the voltage sequence and current sequence of the battery cell, and use it as the characteristic voltage sequence of the battery cell.

[0193] S1304. Obtain the capacity change sequence of the battery cell corresponding to the characteristic voltage sequence timing of the battery cell; the capacity change is the capacity change value generated by the battery cell from the beginning of the working cycle to the intermediate phase transition moment of the corresponding voltage plateau period.

[0194] S1305. Match the voltage-capacity curve with the preset characteristic curve to obtain the range of capacity change in the curve matching region;

[0195] S1306. Determine the intermediate phase transition time within the time range corresponding to the capacity change.

[0196] S1307. Determine the reference voltage-capacity curve based on the voltage-capacity curve of each cell in the battery under test.

[0197] S1308. Obtain the capacity difference curve between the cell's voltage-capacity curve and the reference voltage-capacity curve;

[0198] S1309. Obtain the time corresponding to the maximum peak point in the capacity difference curve as the intermediate phase transition time;

[0199] S1310. Obtain the capacity change of the cell from the start of the corresponding working cycle to the intermediate phase transition moment of the corresponding voltage plateau period, and obtain at least two capacity change values.

[0200] S1311. For each capacity change, obtain the capacity deviation between the capacity change and the reference capacity change; the reference capacity change is the average capacity change of all cells in the battery under test in the same time sequence as the capacity change.

[0201] S1312. Perform linear fitting based on at least two capacity deviations to obtain the slope of the fitted line;

[0202] S1313. Determine the internal short-circuit current and / or internal short-circuit resistance of the battery cell based on the slope of the fitted straight line, as the internal short-circuit electrical parameters of the battery cell.

[0203] S1314. If the internal short-circuit electrical parameters of at least one cell in the battery under test meet the internal short-circuit conditions, the internal short-circuit test result of the battery under test is determined to have an internal short-circuit risk. The internal short-circuit conditions include at least one of the following: the internal short-circuit current is greater than a preset current threshold; the internal short-circuit resistance is less than a preset resistance threshold.

[0204] It should be noted that the descriptions in S1301-S1314 above can be found in the relevant descriptions in the above embodiments, and their effects are similar, so they will not be repeated here.

[0205] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0206] In one embodiment, such as Figure 14 As shown, a battery internal short circuit detection device is provided, including: a time determination module 1401, a capacity acquisition module 1402, a parameter determination module 1403, and a detection result module 1404; wherein:

[0207] The timing determination module 1401 is used to determine the intermediate phase transition time of the corresponding voltage plateau period of each cell in the battery under test based on the electrical parameters of each cell in at least two working cycles.

[0208] The capacity acquisition module 1402 is used to acquire the capacity change of each cell from the start of the corresponding working cycle to the intermediate phase transition moment, and obtain at least two capacity change values ​​for each cell.

[0209] The parameter determination module 1403 is used to determine the internal short-circuit electrical parameters of each cell based on at least two capacity changes of each cell.

[0210] The test result module 1404 is used to determine the internal short circuit test result of the battery under test based on the internal short circuit electrical parameters of each cell.

[0211] Each module in the aforementioned battery internal short-circuit detection device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0212] In one embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the above-described battery internal short circuit detection methods.

[0213] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the above-described battery internal short-circuit detection methods.

[0214] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of any of the above-described battery internal short circuit detection methods.

[0215] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0216] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0217] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for detecting internal short circuits in a battery, characterized in that, The method includes: Based on the electrical parameters of each cell in the battery under test during at least two operating cycles, determine the intermediate phase transition time of the corresponding voltage plateau period of each cell in each operating cycle; The capacity change of each cell from the start of the corresponding working cycle to the intermediate phase transition moment is obtained, and at least two capacity change values ​​of each cell are obtained. The internal short-circuit electrical parameters of each of the cells are determined based on at least two capacity changes of each cell. The internal short-circuit test result of the battery under test is determined based on the internal short-circuit electrical parameters of each cell.

2. The method according to claim 1, characterized in that, The step of determining the intermediate phase transition time of the corresponding voltage plateau period of each cell in the battery under test based on the electrical parameters of each cell in at least two operating cycles includes: For each operating cycle of each of the aforementioned cells, a characteristic voltage sequence of the cell is determined based on the voltage sequence of the cell in that operating cycle; The intermediate phase transition time of the battery cell is determined based on the characteristic voltage sequence of the battery cell.

3. The method according to claim 2, characterized in that, Determining the characteristic voltage sequence of the battery cell based on the voltage sequence of the battery cell during the operating cycle includes: When the battery under test is in a multi-stage stepped current charging state, the equivalent analog voltage sequence of the battery cell under constant analog current is determined based on the voltage sequence and current sequence of the battery cell, and is used as the characteristic voltage sequence of the battery cell. When the battery under test is in other operating states, the open-circuit voltage sequence of the cell is determined based on the voltage sequence and current sequence of the cell, and is used as the characteristic voltage sequence of the cell.

4. The method according to claim 2 or 3, characterized in that, Determining the intermediate phase transition time of the battery cell based on its characteristic voltage sequence includes: The voltage-capacity curve of the battery cell is determined based on the characteristic voltage sequence of the battery cell; the voltage-capacity curve is used to characterize the relationship between the characteristic voltage and the capacity change. The intermediate phase transition time is determined based on the cell's voltage-capacity curve and a reference voltage-capacity curve.

5. The method according to claim 4, characterized in that, The step of determining the voltage-capacity curve of the battery cell based on the characteristic voltage sequence of the battery cell includes: Obtain the capacity change sequence of the battery cell corresponding to the characteristic voltage sequence timing of the battery cell; The voltage-capacity curve is constructed based on the characteristic voltage sequence and the capacity change sequence.

6. The method according to claim 4, characterized in that, The reference voltage-capacity curve includes a preset characteristic curve; determining the intermediate phase transition time based on the cell's voltage-capacity curve and the reference voltage-capacity curve includes: The voltage-capacity curve is matched with the preset feature curve to obtain the range of capacity change in the curve matching region; The intermediate phase transition time is determined within the time range corresponding to the capacity change range.

7. The method according to claim 4, characterized in that, Determining the intermediate phase transition time based on the cell's voltage-capacity curve and a reference voltage-capacity curve includes: The reference voltage-capacity curve is determined based on the voltage-capacity curves of each cell in the battery under test; Obtain the capacity difference curve between the voltage-capacity curve of the battery cell and the reference voltage-capacity curve; The time corresponding to the maximum peak point in the capacity difference curve is obtained as the intermediate phase transition time.

8. The method according to any one of claims 1-3, characterized in that, The determination of the internal short-circuit electrical parameters of each of the battery cells based on at least two capacity changes includes: For each capacity change of each of the aforementioned cells, the capacity deviation between the capacity change and a reference capacity change is obtained; the reference capacity change is the average capacity change of all cells in the battery under test in the same time sequence as the capacity change. The internal short-circuit electrical parameters of the cell are determined based on at least two capacity deviations.

9. The method according to claim 8, characterized in that, The determination of the internal short-circuit electrical parameters of the cell based on at least two capacity deviations includes: A linear fit is performed based on the at least two capacity deviations to obtain the slope of the fitted line; The internal short-circuit current and / or internal short-circuit resistance of the battery cell are determined based on the slope of the fitted straight line, and are used as the internal short-circuit electrical parameters of the battery cell.

10. The method according to any one of claims 1-3, characterized in that, The internal short-circuit electrical parameters include internal short-circuit current and / or internal short-circuit resistance; determining the internal short-circuit detection result of the battery under test based on the internal short-circuit electrical parameters of each cell includes: If the internal short-circuit electrical parameters of at least one cell in the battery under test meet the internal short-circuit conditions, the internal short-circuit detection result of the battery under test is determined to have an internal short-circuit risk. The internal short-circuit condition includes at least one of the following: The internal short-circuit current is greater than a preset current threshold. The internal short-circuit resistance is less than a preset resistance threshold.

11. A battery internal short circuit detection device, characterized in that, The device includes: The timing determination module is used to determine the intermediate phase transition time of the corresponding voltage plateau period of each cell in the battery under test based on the electrical parameters of each cell in at least two working cycles. The capacity acquisition module is used to acquire the capacity change of each cell from the start of the corresponding working cycle to the intermediate phase transition moment, and to obtain at least two capacity change values ​​for each cell. The parameter determination module is used to determine the internal short-circuit electrical parameters of each of the battery cells based on at least two capacity changes of each of the battery cells. The detection result module is used to determine the internal short-circuit detection result of the battery under test based on the internal short-circuit electrical parameters of each cell.

12. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 10.

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

14. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 10.

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