Method for judging self-discharge abnormal battery cell, judging device, and electronic device

Abstract

The application discloses a kind of self-discharge abnormal battery judging method, judging device and electronic equipment, the judging method includes: obtaining the state of charge-open circuit voltage curve of battery;Any inflection point position corresponding open circuit voltage in the state of charge-open circuit voltage curve is determined as the initial voltage of the battery;n target voltages of the battery obtained after the target operation of the battery is cycled n times are obtained, wherein the target operation is one-to-one corresponding with the target voltage, the target operation is to charge the battery with a preset current for a first preset time, and discharge the battery with the preset current for the first preset time, n is an integer greater than 1;For each target voltage, based on the initial voltage and the target voltage, the voltage difference between the initial voltage and the target voltage is determined;In the case where the n voltage differences determined in turn show an increasing trend, the battery is judged to be a self-discharge abnormal battery.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a method, device and electronic device for judging abnormal self-discharge of a battery cell. Background Technology

[0002] During the initial production and use of new energy power equipment such as electric vehicles and energy storage power stations, consistency screening and control of battery cells or battery packs are generally carried out to ensure better performance of the equipment. Currently, common control items include cell capacity, voltage, internal resistance, and self-discharge. Among these, self-discharge is the most difficult to control, and its consequences are the most serious.

[0003] In related technologies, companies mainly use the static method to sort battery cells for self-discharge. The main process involves letting the cells sit for different numbers of days after capacity testing, measuring the voltage drop of the cells daily, and statistically analyzing the mean and standard deviation (σ) of the voltage drop. Based on the mean and standard deviation (σ) of the voltage drop, a sorting threshold is determined, and then the cell is judged to have abnormal self-discharge according to the determined sorting threshold. However, since the voltage of a single battery cell is generally between 0-5V, and the daily voltage drop of the cell is often not significant, the voltage measuring device will have a certain error when testing the voltage drop. Therefore, the accuracy of judging whether a battery cell has abnormal self-discharge using the above method is relatively low. Summary of the Invention

[0004] This application discloses a method, device, and electronic equipment for judging abnormal self-discharge cells, which can improve the accuracy of judging abnormal self-discharge cells.

[0005] To solve the above problems, this application adopts the following technical solution:

[0006] In a first aspect, embodiments of this application disclose a method for determining a battery cell with abnormal self-discharge, comprising: acquiring the state-of-charge-open-circuit voltage curve of the battery cell; determining the open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve as the initial voltage of the battery cell; acquiring n target voltages of the battery cell obtained after performing n target operations on the battery cell, wherein the target operation corresponds one-to-one with the target voltage, the target operation being charging the battery cell with a preset current for a first preset time and discharging the battery cell with the preset current for a first preset time, and n being an integer greater than 1; for each target voltage, determining the voltage difference between the initial voltage and the target voltage based on the initial voltage and the target voltage; and determining that the battery cell is a battery cell with abnormal self-discharge when the n determined voltage differences show an increasing trend.

[0007] Secondly, this application discloses a device for determining a self-discharge abnormal battery cell, comprising: a first acquisition module for acquiring the state-of-charge-open-circuit voltage curve of the battery cell; a first determination module for determining the open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve as the initial voltage of the battery cell; a second acquisition module for acquiring n target voltages of the battery cell obtained after performing n target operations on the battery cell, wherein the target operation corresponds one-to-one with the target voltage, the target operation being charging the battery cell with a preset current for a first preset time and discharging the battery cell with the preset current for a first preset time, and n being an integer greater than 1; a second determination module for determining the voltage difference between the initial voltage and the target voltage for each target voltage based on the initial voltage and the target voltage; and a judgment module for determining that the battery cell is a self-discharge abnormal battery cell if the n determined voltage differences show an increasing trend.

[0008] Thirdly, embodiments of this application provide an electronic device including a processor and a memory, wherein the memory stores programs or instructions executable on the processor, and the programs or instructions, when executed by the processor, implement the steps of the method described in the first aspect.

[0009] Fourthly, embodiments of this application provide a readable storage medium on which a program or instructions are stored, which, when executed by a processor, implement the steps of the method described in the first aspect.

[0010] This application provides a method for determining whether a battery cell has abnormal self-discharge. By acquiring the state-of-charge (POC)-open-circuit voltage (OCV) curve of the battery cell, the open-circuit voltage corresponding to any inflection point in the OCC-OCV curve is determined as the initial voltage of the battery cell. Then, n target voltages are obtained after performing n cycles of charging the battery cell with a preset current for a first preset time and discharging the battery cell with a preset current for the first preset time. For each target voltage, the voltage difference between the initial voltage and the target voltage is determined based on the initial voltage and the target voltage. Finally, if the n determined voltage differences show an increasing trend, the battery cell is determined to be a battery cell with abnormal self-discharge. The method disclosed in this application does not require specific test values ​​to determine whether a battery cell has abnormal self-discharge; it only needs to be based on the changing trend of the n voltage differences to determine whether the battery cell has abnormal self-discharge, thus improving the accuracy of the determination. Attached Figure Description

[0011] Figure 1 This is a flowchart illustrating a method for determining a self-discharge abnormal battery cell disclosed in an embodiment of this application.

[0012] Figure 2 This application discloses a state of charge-open circuit voltage curve for a battery cell.

[0013] Figure 3a This is a graph showing the trend of battery cell charging and discharging efficiency as disclosed in an embodiment of this application.

[0014] Figure 3b This is a pressure difference variation trend diagram disclosed in an embodiment of this application;

[0015] Figure 4a This is a graph showing the change trend of the charging and discharging efficiency of another battery cell disclosed in an embodiment of this application;

[0016] Figure 4b This is another pressure difference variation trend diagram disclosed in the embodiments of this application;

[0017] Figure 5a This is a graph showing the changing trend of the charging and discharging efficiency of another type of battery cell disclosed in an embodiment of this application.

[0018] Figure 5b This is another pressure difference variation trend diagram disclosed in the embodiments of this application;

[0019] Figure 6a This is a graph showing the changing trend of the charging and discharging efficiency of another type of battery cell disclosed in an embodiment of this application.

[0020] Figure 6b This is another pressure difference variation trend diagram disclosed in the embodiments of this application;

[0021] Figure 7 This is a schematic diagram of the structure of a device for determining abnormal self-discharge of a battery cell disclosed in an embodiment of this application;

[0022] Figure 8 This is a schematic diagram of the structure of an electronic device disclosed in an embodiment of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the electrically connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] The following description, in conjunction with the accompanying drawings, details the method, device, and electronic equipment for determining self-discharge abnormal cells disclosed in this application, through specific embodiments and application scenarios.

[0026] Figure 1 This is a flowchart illustrating a method for determining a self-discharge abnormal battery cell disclosed in an embodiment of this application. Figure 1 As shown, the method includes the following steps:

[0027] S110. Obtain the State of Charge-Open Circuit Voltage (SOC-OCV) curve of the battery cell.

[0028] For example, the SOC-OCV curve of a certain 150Ah battery cell is as follows: Figure 2 As shown. It should be noted that the SOC-OCV curves may differ for different battery cells. Figure 2 This is just one example.

[0029] S120. The open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve is determined as the initial voltage of the battery cell.

[0030] In this application, by determining the open-circuit voltage corresponding to any inflection point in the SOC-OCV curve as the initial voltage of the battery cell, the subsequent determination results become more obvious and intuitive. Optionally, the open-circuit voltage corresponding to the inflection point where the SOC-OCV curve transitions from steep to gentle can be determined as the initial voltage of the battery cell.

[0031] by Figure 2 For example, the open-circuit voltage corresponding to 5% SOC can be determined as the initial voltage of the cell, or the open-circuit voltage corresponding to 50% SOC can be determined as the initial voltage of the cell.

[0032] S130. Obtain n target voltages of the battery cell after performing n target operations on the battery cell.

[0033] The target operation corresponds one-to-one with the target voltage. The target operation is to charge the battery cell with a preset current for a first preset time and discharge the battery cell with the preset current for a first preset time, where n is an integer greater than 1.

[0034] In other words, after each cycle of charging the battery cell with a preset current for a first preset time and discharging the battery cell with a preset current for a first preset time, a target voltage is obtained.

[0035] In this application, starting from the initial voltage, n target voltages are obtained by repeating the target operation n times.

[0036] It should be noted that if the cell has no self-discharge abnormality, after performing the target operation on the cell, ignoring temperature rise and polarization, the target voltage of the cell is equal to or close to the initial voltage of the cell. Specifically, when the difference between the initial voltage and the target voltage of the cell is within ±1% of the initial voltage, the target voltage is considered to be close to the initial voltage. If the cell has a self-discharge abnormality, after repeatedly performing the target operation n times, the obtained target voltage of the cell will gradually move away from the initial voltage, that is, the voltage difference between the initial voltage and the target voltage will show an increasing trend.

[0037] S140. For each target voltage, determine the voltage difference between the initial voltage and the target voltage based on the initial voltage and the target voltage.

[0038] S150. If the n differential pressures are determined to be increasing in sequence, the cell is determined to be a cell with abnormal self-discharge.

[0039] For example, based on n determined pressure differences, a graph can be plotted with the number of cycles as the x-axis and the pressure difference as the y-axis to more intuitively determine the changing trend of the n pressure differences. Then, if the n determined pressure differences show an increasing trend, it can be determined that the cell is a cell with abnormal self-discharge.

[0040] This application provides a method for determining whether a battery cell has abnormal self-discharge. By acquiring the state-of-charge (POC)-open-circuit voltage (OCV) curve of the battery cell, the open-circuit voltage corresponding to any inflection point in the OCC-OCV curve is determined as the initial voltage of the battery cell. Then, n target voltages are obtained after performing n cycles of charging the battery cell with a preset current for a first preset time and discharging the battery cell with a preset current for the first preset time. For each target voltage, the voltage difference between the initial voltage and the target voltage is determined based on the initial voltage and the target voltage. Finally, if the n determined voltage differences show an increasing trend, the battery cell is determined to be a battery cell with abnormal self-discharge. The method disclosed in this application does not require specific test values ​​to determine whether a battery cell has abnormal self-discharge; it only needs to be based on the changing trend of the n voltage differences to determine whether the battery cell has abnormal self-discharge, thus improving the accuracy of the determination.

[0041] Furthermore, by using the judgment method disclosed in this application to determine whether a battery cell has abnormal self-discharge, since the battery cell has undergone n charge-discharge cycles, it is possible to screen out battery cells that begin to exhibit abnormal self-discharge after a certain number of charge-discharge cycles (e.g., the diaphragm is punctured by force after a foreign object has been circulated). Moreover, using the judgment method disclosed in this application, the corresponding parameters can be adjusted according to the actual project situation, thereby improving the accuracy of the judgment. For example, for battery cells with low self-discharge rates, the number of cycles can be increased, the preset current reduced, and the duration of the first preset time increased to improve the accuracy of the judgment.

[0042] Considering the impact of cell voltage sampling accuracy on the judgment result, in this embodiment, after charging the cell with a preset current for a first preset time, the method may further include: acquiring the charging energy of the cell during the first preset time; after discharging the cell with the preset current for a first preset time, the method may further include: acquiring the discharging energy of the cell during the first preset time; before determining that the cell is a self-discharge abnormal cell when the n sequentially determined voltage differences show an increasing trend, the method may further include: determining the charge-discharge efficiency of the cell based on the discharge energy and the charging energy for each group of charging energy and discharge energy; determining that the cell is a self-discharge abnormal cell when the n sequentially determined voltage differences show an increasing trend may include: determining that the cell is a self-discharge abnormal cell when the n sequentially determined voltage differences show an increasing trend and the n sequentially determined charge-discharge efficiencies show a decreasing trend.

[0043] It should be noted that each execution of the target operation yields a set of charging energy and discharging energy of the battery cell within a first preset time period, thus providing the charge / discharge efficiency of the battery cell. In other words, there is a one-to-one correspondence between the target operation and the charge / discharge efficiency. If the battery cell has no self-discharge abnormalities, its charge / discharge efficiency will be a relatively stable value. If the battery cell has abnormal self-discharge, the rate of voltage increase or decrease will differ when a charging or discharging pulse is applied. For example, if a... Figure 2 The open-circuit voltage corresponding to 5% SOC shown is the initial voltage of the battery cell. At this time, the voltage change during the discharge process will be amplified. Specifically, the battery cell discharge current = self-discharge current - preset current. However, the voltage change during the charging process will be reduced. Specifically, the battery cell total charging current = preset current - self-discharge current. The external manifestation of this is that the charging and discharging efficiency of the battery cell continues to decrease.

[0044] For example, based on the determined n charge and discharge efficiencies, a graph can be plotted with the number of cycles as the x-axis and the charge and discharge efficiency as the y-axis to more intuitively determine the changing trend of the n charge and discharge efficiencies. If the n charge and discharge efficiencies show a decreasing trend, then the cell is a cell with abnormal self-discharge.

[0045] In one implementation, determining the charge / discharge efficiency of the battery cell based on the discharge energy and the charging energy for each set of charging energy and discharge energy may include: determining the charge / discharge efficiency of the battery cell using the following formula: Charge / discharge efficiency = Discharge energy / Charging energy * 100%.

[0046] The judgment method disclosed in this application uses the changing trends of n voltage differences obtained by cyclically performing the target operation n times, combined with the changing trends of n charging and discharging efficiencies, to judge whether the battery cell has abnormal self-discharge, which can further improve the accuracy of judging battery cells with abnormal self-discharge.

[0047] In one implementation, obtaining the charging energy of the battery cell within the first preset time period may include: obtaining a first current and a first voltage during the charging process of the battery cell; determining the charging energy of the battery cell within the first preset time period based on the first current and the first voltage; obtaining the discharging energy of the battery cell within the first preset time period may include: obtaining a second current and a second voltage during the discharging process of the battery cell; determining the discharging energy of the battery cell within the first preset time period based on the second current and the second voltage.

[0048] For example, determining the charging energy of the battery cell within the first preset time period based on the first current and the first voltage may include: determining the charging energy of the battery cell within the first preset time period using the following formula; E c1=∫I²*U²=∑I²*U², where, E c1 Let I2 be the charging energy of the battery cell within the first preset time period, and U2 be the first current and U2 be the first voltage. Determining the discharge energy of the battery cell within the first preset time period based on the second current and the second voltage may include: determining the discharge energy of the battery cell within the first preset time period using the following formula; E c2 =∫I3*U3=∑I3*U3, where, E c2 I3 represents the discharge energy of the battery cell within the first preset time period, and U3 represents the second current and the second voltage.

[0049] In this embodiment, the target operation can be charging the battery cell with a preset current for a first preset time, letting the battery cell rest for a second preset time, discharging the battery cell with the preset current for a first preset time, and then letting the battery cell rest for the second preset time. That is, after charging the battery cell with the preset current for a first preset time, letting the battery cell rest for a second preset time, and after the battery cell voltage tends to stabilize, discharging the battery cell with the preset current for a first preset time, and then letting the battery cell rest for the second preset time, and after the battery cell voltage tends to stabilize, obtaining the battery cell voltage at this time as the target voltage, thereby improving the accuracy of the obtained target voltage and thus improving the accuracy of judging whether the battery cell has abnormal self-discharge. It should be noted that this application does not specifically limit the value of the second preset time; the specific value of the second preset time can be determined according to actual needs.

[0050] In this application, after determining the open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve as the initial voltage of the battery cell, the method may further include: determining the initial state of charge corresponding to the initial voltage based on the state-of-charge-open-circuit voltage curve; adjusting the state of charge of the battery cell to the initial state of charge; and allowing the battery cell to rest for a third preset time. That is, after adjusting the state of charge of the battery cell to the initial state of charge corresponding to the selected initial voltage and allowing the battery cell to rest for a third preset time, the target operation is then performed on the battery cell to obtain the target voltage. It should be noted that this application does not specifically limit the value of the third preset time; the specific value of the third preset time can be determined according to actual needs.

[0051] Furthermore, to avoid temperature rise and polarization accumulation in the battery cell, the preset current and the first preset time should not be too large. In this application, the magnitude of the preset current can be determined based on the rated capacity of the battery cell. In one implementation, the current corresponding to 1 / 10 of the rated capacity of the battery cell can be determined as the magnitude of the preset current. For example, when the rated capacity of the battery cell is 150Ah, the magnitude of the preset current is 15A; when the rated capacity of the battery cell is 6Ah, the magnitude of the preset current is 0.6A. In addition, the magnitude of the preset current can also be adjusted according to the precision of the device performing the target operation. When the precision of the device performing the target operation is high, a relatively small preset current can be selected, and correspondingly, the duration of the selected first preset time is relatively long. In this application, the duration of the first preset time can be determined based on the rated capacity of the battery cell and the severity of its self-discharge. When the battery cell capacity is small, the first preset time can be shorter; when the battery cell capacity is large, the first preset time can be longer. When the severity of the self-discharge is high, the first preset time can be shorter; when the severity of the self-discharge is low, the first preset time can be longer. For example, when the rated capacity of the battery cell is 150Ah, the first preset time can be from 1 minute to 3 minutes.

[0052] In one implementation, determining the voltage difference between the initial voltage and the target voltage based on the initial voltage and the target voltage may include: determining the voltage difference between the initial voltage and the target voltage using the following formula: Voltage difference = (U0 - U4) * 1000, where U0 is the initial voltage and U4 is the target voltage; determining that the cell is a self-discharge abnormal cell when the n successively determined voltage differences show an increasing trend may include: determining that the cell is a self-discharge abnormal cell when the n successively determined voltage differences show an upward trend. The above formula, by multiplying the difference between the initial voltage and the target voltage by 1000, amplifies the voltage difference between the initial voltage and the target voltage, thereby enabling a more intuitive determination of the changing trend of the n voltage differences.

[0053] This application provides a method for determining a battery cell with abnormal self-discharge. The method involves acquiring the state-of-charge (POC)-open-circuit voltage (OCV) curve of the battery cell, determining the open-circuit voltage corresponding to any inflection point in the OCC curve as the initial voltage of the battery cell, adjusting the OCC of the battery cell to the initial OCC corresponding to the initial voltage, and allowing the battery cell to rest for a third preset time. Then, the method acquires the voltage differences between n initial voltages and a target voltage, as well as the charge / discharge efficiencies of n batteries, obtained after performing the target operation of charging the battery cell with a preset current for a first preset time, allowing the battery cell to rest for a second preset time, discharging the battery cell with a preset current for a first preset time, and allowing the battery cell to rest for a second preset time. If the n voltage differences show an increasing trend and the n charge / discharge efficiencies show a decreasing trend, the battery cell is determined to be a battery cell with abnormal self-discharge.

[0054] For example, after adjusting the state of charge of the battery cell to the initial state of charge corresponding to the initial voltage and letting the battery cell stand for 2 hours, the battery cell is charged with a current of 15A for 2 minutes, left to stand for 1 minute, and then discharged with a current of 15A for 2 minutes and left to stand for 1 minute 100 times at a sampling frequency of 1 second per cycle. The whole process takes 12 hours. Compared with the method for judging self-discharge abnormal battery cells in related technologies, it can save a lot of time and thus save labor costs.

[0055] Furthermore, when it is necessary to analyze the entire battery pack with abnormal self-discharge, but there is no corresponding reference data, the judgment method disclosed in this application can be used to make a judgment simply by checking whether the trend of the suspected object is consistent with that of other battery cells.

[0056] Taking a battery pack composed of cells with a nominal capacity of 150Ah as an example, Figure 3a To be Figure 2 The open-circuit voltage corresponding to 5% SOC is determined as the initial voltage of the cell. The trend graph of the cell's charge-discharge efficiency is obtained after 100 cycles of operation. Figure 3b To be Figure 2 The open-circuit voltage corresponding to 5% SOC is determined as the initial voltage of the cell. The voltage difference trend graph obtained after 100 cycles of operation is shown. Figure 4a To be Figure 2 The open-circuit voltage corresponding to 50% SOC is determined as the initial voltage of the cell. The trend graph of the cell's charge-discharge efficiency is obtained after 100 cycles of operation. Figure 4b To be Figure 2 The open-circuit voltage corresponding to 50% SOC is determined as the initial voltage of the cell. The voltage difference trend graph obtained after 100 cycles of operation is shown. Figure 5a To be Figure 2The open-circuit voltage corresponding to 35% SOC is determined as the initial voltage of the cell. The trend graph of the cell's charge-discharge efficiency is obtained after 100 cycles of operation. Figure 5b To be Figure 2 The open-circuit voltage corresponding to 35% SOC is determined as the initial voltage of the cell. The voltage difference trend graph obtained after 100 cycles of operation is shown. Figure 6a To be Figure 2 The open-circuit voltage corresponding to 80% SOC is determined as the initial voltage of the cell. The trend graph of the cell's charge-discharge efficiency is obtained after 100 cycles of operation. Figure 6b To be Figure 2 The open-circuit voltage corresponding to 80% SOC is determined as the initial voltage of the cell. The voltage difference trend is obtained after 100 cycles of operation. 5% SOC and 50% SOC are the inflection points in the SOC-OCV curve, while 35% SOC and 80% SOC are the positions where there is no obvious inflection point in the SOC-OCV curve.

[0057] according to Figures 3a to 4b It can be seen that the voltage difference and charge / discharge efficiency trends of cell 1 are significantly different from those of other cells. Compared to other cells, cell 1 has the lowest charge / discharge efficiency, which continues to decrease with each cycle. Furthermore, the voltage difference of cell 1 increases with each cycle, while the other cells show very stable trends in both charge / discharge efficiency and voltage difference. Figures 3a to 4b , Figures 5a to 6b The change trend is not obvious, and the charging and discharging efficiency does not show a significant downward trend. Therefore, this application determines the open circuit voltage corresponding to any inflection point in the state of charge-open circuit voltage curve as the initial voltage of the cell, which can improve the accuracy of judging cells with abnormal self-discharge.

[0058] The self-discharge abnormality battery cell determination method provided in this application embodiment can be executed by a self-discharge abnormality battery cell determination device. This application embodiment uses the execution of the self-discharge abnormality battery cell determination method by a self-discharge abnormality battery cell determination device as an example to illustrate the self-discharge abnormality battery cell determination device provided in this application embodiment.

[0059] Figure 7 This is a schematic diagram of a device for determining abnormal self-discharge of a battery cell disclosed in an embodiment of this application. Figure 7 As shown, the self-discharge abnormal cell judgment device 700 includes: a first acquisition module 710, a first determination module 720, a second acquisition module 730, a second determination module 740, and a judgment module 750.

[0060] In this application, a first acquisition module 710 is used to acquire the state-of-charge-open-circuit voltage curve of the battery cell; a first determination module 720 is used to determine the open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve as the initial voltage of the battery cell; a second acquisition module 730 is used to acquire n target voltages of the battery cell obtained after performing n target operations on the battery cell, wherein the target operation corresponds one-to-one with the target voltage, and the target operation is to charge the battery cell with a preset current for a first preset time and discharge the battery cell with the preset current for a first preset time, where n is an integer greater than 1; a second determination module 740 is used to determine the voltage difference between the initial voltage and the target voltage for each target voltage based on the initial voltage and the target voltage; and a judgment module 750 is used to determine that the battery cell is a self-discharge abnormal battery cell if the n determined voltage differences show an increasing trend.

[0061] In one implementation, the second acquisition module 730 is further configured to acquire the charging energy of the battery cell within the first preset time after charging the battery cell with the preset current for a first preset time; the second acquisition module 730 is further configured to acquire the discharge energy of the battery cell within the first preset time after discharging the battery cell with the preset current for a first preset time; the second determination module 740 is further configured to determine the charge-discharge efficiency of the battery cell based on the discharge energy and the charging energy for each group of charging energy and discharge energy before determining that the battery cell is a self-discharge abnormal battery cell when the n determined voltage differences show an increasing trend; the determination module 750 determining that the battery cell is a self-discharge abnormal battery cell when the n determined voltage differences show an increasing trend includes: determining that the battery cell is a self-discharge abnormal battery cell when the n determined voltage differences show an increasing trend and the n determined charge-discharge efficiencies show a decreasing trend.

[0062] In one implementation, the second acquisition module 730 acquires the charging energy of the battery cell within the first preset time period, including: acquiring a first current and a first voltage during the charging process of the battery cell; and determining the charging energy of the battery cell within the first preset time period based on the first current and the first voltage. The second acquisition module 730 also acquires the discharging energy of the battery cell within the first preset time period, including: acquiring a second current and a second voltage during the discharging process of the battery cell; and determining the discharging energy of the battery cell within the first preset time period based on the second current and the second voltage.

[0063] In one implementation, the target operation is to charge the battery cell with a preset current for a first preset time, leave the battery cell idle for a second preset time, discharge the battery cell with the preset current for the first preset time, and leave the battery cell idle for the second preset time.

[0064] In one implementation, the method further includes: the first determining module 720, which is further configured to determine an initial state of charge corresponding to the initial voltage based on the state of charge-open circuit voltage curve after determining the open circuit voltage corresponding to any inflection point position in the state of charge-open circuit voltage curve as the initial voltage of the battery cell; and an adjusting module, which is configured to adjust the state of charge of the battery cell to the initial state of charge and place the battery cell in a static state for a third preset time.

[0065] In one implementation, the magnitude of the preset current is determined based on the rated capacity of the battery cell.

[0066] In one implementation, the second determining module 740 determines the voltage difference between the initial voltage and the target voltage based on the initial voltage and the target voltage, including: determining the voltage difference between the initial voltage and the target voltage using the following formula: voltage difference = (U0-U4)*1000, where U0 is the initial voltage and U4 is the target voltage; the judging module 750 judges the cell as a self-discharge abnormal cell when the n sequentially determined voltage differences show an increasing trend, including: judging the cell as a self-discharge abnormal cell when the n sequentially determined voltage differences show an upward trend.

[0067] The device for determining the self-discharge abnormality of the battery cell in this application embodiment can be an electronic device or a component within an electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal or any other device besides a terminal.

[0068] The device for determining self-discharge abnormal cells provided in this application embodiment can realize the various processes implemented in the method embodiment for determining self-discharge abnormal cells. To avoid repetition, it will not be described again here.

[0069] Optionally, such as Figure 8 As shown, this application embodiment also provides an electronic device 800, including a processor 801 and a memory 802. The memory 802 stores a program or instructions that can run on the processor 801. When the program or instructions are executed by the processor 801, they implement the various steps of the above-described method embodiment for judging self-discharge abnormal cells and can achieve the same technical effect. To avoid repetition, they will not be described again here.

[0070] It should be noted that the electronic devices in the embodiments of this application include the mobile electronic devices and non-mobile electronic devices described above.

[0071] This application also provides a readable storage medium storing a program or instructions. When the program or instructions are executed by a processor, they implement the various processes of the above-described method for judging self-discharge abnormal battery cells and achieve the same technical effect. To avoid repetition, they will not be described again here.

[0072] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0073] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described method embodiment for judging self-discharge abnormal cells, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0074] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0075] This application provides a computer program product, which is stored in a storage medium and executed by at least one processor to implement the various processes of the above-described method for judging self-discharge abnormal battery cells, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0076] The above embodiments of this application focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.

[0077] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining abnormal self-discharge in a battery cell, characterized in that, include: Obtain the state of charge-open circuit voltage curve of the battery cell; The open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve is determined as the initial voltage of the battery cell; Based on the state-of-charge-open-circuit voltage curve, determine the initial state of charge corresponding to the initial voltage; The state of charge of the battery cell is adjusted to the initial state of charge, and the battery cell is left to stand for a third preset time. Obtain n target voltages of the battery cell after performing n target operations on the battery cell, wherein the target operation corresponds one-to-one with the target voltage, and the target operation is to charge the battery cell with a preset current for a first preset time and discharge the battery cell with the preset current for a first preset time, where n is an integer greater than 1. For each target voltage, the voltage difference between the initial voltage and the target voltage is determined based on the initial voltage and the target voltage; If the n differential pressures are determined to increase sequentially, the cell is determined to be a cell with abnormal self-discharge.

2. The judgment method according to claim 1, characterized in that, After charging the battery cell with a preset current for a first preset time, the method further includes: Obtain the charging energy of the battery cell within the first preset time period; After discharging the battery cell with the preset current for the first preset time, the method further includes: Obtain the discharge energy of the battery cell within the first preset time period; Before determining that the battery cell is a self-discharge abnormality battery cell when the n sequentially determined voltage differences show an increasing trend, the method further includes: For each set of charging energy and discharging energy, the charging and discharging efficiency of the battery cell is determined based on the discharging energy and the charging energy. The step of determining that the battery cell is a self-discharge abnormal cell when the n sequentially determined voltage differences show an increasing trend includes: If the n sequentially determined differential pressures show an increasing trend and the n sequentially determined charge / discharge efficiencies show a decreasing trend, then the battery cell is determined to be a self-discharge abnormal battery cell.

3. The judgment method according to claim 2, characterized in that, The step of acquiring the charging energy of the battery cell within the first preset time period includes: Acquire the first current and the first voltage during the charging process of the battery cell; Based on the first current and the first voltage, the charging energy of the battery cell within the first preset time period is determined; The step of obtaining the discharge energy of the battery cell within the first preset time period includes: Obtain the second current and the second voltage during the discharge process of the battery cell; Based on the second current and the second voltage, the discharge energy of the battery cell within the first preset time period is determined.

4. The judgment method according to claim 1, characterized in that, The target operation is to charge the battery cell with a preset current for a first preset time, leave the battery cell idle for a second preset time, discharge the battery cell with the preset current for a first preset time, and leave the battery cell idle for the second preset time.

5. The judgment method according to claim 1, characterized in that, The magnitude of the preset current is determined based on the rated capacity of the battery cell.

6. The determination method according to claim 1, characterized in that, Determining the voltage difference between the initial voltage and the target voltage based on the initial voltage and the target voltage includes: The voltage difference between the initial voltage and the target voltage is determined using the following formula; Pressure difference = (U0 - U4) 1000, where U0 is the initial voltage and U4 is the target voltage; The step of determining that the battery cell is a self-discharge abnormal cell when the n sequentially determined voltage differences show an increasing trend includes: If the n differential pressures are determined to be increasing sequentially, the battery cell is determined to be a self-discharge abnormal battery cell.

7. A device for determining abnormal self-discharge of a battery cell, characterized in that, include: The first acquisition module is used to acquire the state of charge-open circuit voltage curve of the battery cell; The first determining module is used to determine the open-circuit voltage corresponding to any inflection point in the state-of-charge-open-circuit voltage curve as the initial voltage of the battery cell; The first determining module is further configured to determine the initial state of charge corresponding to the initial voltage based on the state of charge-open circuit voltage curve; An adjustment module is used to adjust the state of charge of the battery cell to the initial state of charge and to place the battery cell at rest for a third preset time. The second acquisition module is used to acquire n target voltages of the battery cell after performing n target operations on the battery cell. The target operation corresponds one-to-one with the target voltage. The target operation is to charge the battery cell with a preset current for a first preset time and discharge the battery cell with the preset current for a first preset time. n is an integer greater than 1. The second determining module is used to determine, for each target voltage, the voltage difference between the initial voltage and the target voltage based on the initial voltage and the target voltage; The judgment module is used to determine that the battery cell is a self-discharge abnormal battery cell when the n sequentially determined voltage differences show an increasing trend.

8. An electronic device, characterized in that, It includes a processor and a memory, the memory storing programs or instructions that can run on the processor, the programs or instructions being executed by the processor to implement the steps of the method for determining self-discharge abnormal cells as described in any one of claims 1-6.

9. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions, which, when executed by a processor, implement the steps of the method for determining a self-discharge abnormal battery cell as described in any one of claims 1-6.

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