Method for detecting a self-discharge condition of a battery pack, vehicle, and computer storage medium

Abstract

A method for detecting a self-discharge state of a battery pack, a vehicle, and a computer storage medium. The method for detecting a self-discharge state of a battery pack includes: acquiring charge and discharge data of each cell of the battery pack (S1); generating a dQ / dV curve of each cell according to the charge and discharge data (S2); determining voltage inflection point characteristic information according to the dQ / dV curve of each cell (S3); and determining a self-discharge state of the battery pack according to the voltage inflection point characteristic information of each cell (S4).

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This disclosure claims priority to Chinese Patent Application No. 202211704489.1, entitled "Method for detecting self-discharge state of battery pack, vehicle and computer storage medium," filed with the State Intellectual Property Office of China on December 29, 2022, which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to the field of vehicle technology, and more particularly to a method, vehicle, and computer storage medium for detecting a self-discharge condition of a battery pack. [Background technology]

[0003] Transportation vehicles, such as electric cars, aircraft, and ships, require multiple batteries connected in series or parallel to provide the required power. However, due to cost and technical constraints, battery manufacturers cannot achieve complete consistency in the production of battery cells, and some cells may even exhibit extreme self-discharge abnormalities. Abnormal self-discharge in even one battery cell in a package can damage vehicles, ships, and aircraft, and even lead to serious events such as thermal runaway. Therefore, detecting abnormal self-discharge in battery cells is extremely important for the lithium electronic battery market. Summary of the Invention

[0004] The present disclosure aims to solve at least one of the technical problems existing in the prior art. Therefore, the present disclosure aims to propose a method for detecting the self-discharge state of a battery pack, and by using this method, the self-discharge state of a single cell in the battery pack can be detected.

[0005] A second object of the present disclosure is to propose a vehicle.

[0006] A third object of the present disclosure is to propose a computer storage medium.

[0007] In order to solve the above problems, an embodiment according to a first aspect of the present disclosure provides a method for detecting a self-discharge state of a battery pack, the method including: obtaining charge and discharge data of each single cell of the battery pack; generating a dQ / dV capacity curve of each single cell according to the charge and discharge data; determining voltage inflection point characteristic information according to the dQ / dV capacity curve of each single cell; and determining a self-discharge state of the battery pack according to the voltage inflection point characteristic information.

[0008] In an embodiment of the present disclosure, according to a method for detecting a self-discharge state of a battery pack, a dQ / dV capacity curve of each single cell is generated by using charge and discharge data of each single cell of the battery pack during use, and voltage inflection point characteristic information of each single cell is determined according to the dQ / dV capacity curve of each single cell, thereby determining the self-discharge state of the battery pack through the difference between the voltage inflection point characteristic information of each single cell, thereby realizing detection of the self-discharge situation of each single cell in the battery pack, further, the application scenario of this method is not limited, and this method may be applied to detecting the self-discharge state of a battery pack throughout its entire life cycle, and has wide applicability.

[0009] In some embodiments, the dQ / dV capacity curve of each single cell is generated according to the charge and discharge data, which includes: determining the SOC value of each single cell at the initial time of entering the charge / discharge phase; determining the initial capacity value of each single cell at the initial time of entering the charge / discharge phase according to the nominal capacity value and SOC value of each single cell; determining the capacity increment of each single cell at each time after entering the charge / discharge phase; determining the real-time capacity value of each single cell in the charge / discharge phase according to the initial capacity value and capacity increment; determining the real-time voltage value of each single cell in the charge / discharge phase, and generating the dQ / dV capacity curve of each single cell according to the initial capacity value, real-time capacity value, and real-time voltage value.

[0010] In some embodiments, the voltage inflection point characteristic information is determined according to the dQ / dV capacity curve of each single cell, which includes: determining, among all the dQ / dV capacity curves, a first dQ / dV capacity curve in which a high-voltage inflection point occurs earliest, a second dQ / dV capacity curve in which a high-voltage inflection point occurs latest, and a third dQ / dV capacity curve in which a low-voltage inflection point occurs latest; determining, according to the first dQ / dV capacity curve, a first capacitance value corresponding to the first high-voltage inflection point in the first dQ / dV capacity curve; determining, according to the second dQ / dV capacity curve, a second capacitance value corresponding to the second high-voltage inflection point in the second dQ / dV capacity curve; and determining, according to the third dQ / dV capacity curve, a third capacitance value corresponding to the low-voltage inflection point in the third dQ / dV capacity curve.

[0011] In some embodiments, the self-discharge state of the battery pack is determined according to the voltage inflection point characteristic information, which includes: determining a first difference value between the second capacity value and the first capacity value, and determining the self-discharge state of the battery pack according to the first difference value; and / or determining a second difference value between the first capacity value and a third capacity value, and determining the self-discharge state of the battery pack according to the second difference value; and / or determining a theoretical capacity value of a single cell corresponding to a third high-voltage inflection point on the theoretical dQ / dV capacity curve, and determining a third difference value between the second capacity value and the theoretical capacity value, and determining the self-discharge state of the battery pack according to the third difference value.

[0012] In some embodiments, the self-discharge state of the battery pack is determined according to the first difference value, which includes: determining whether the first difference value is within a first preset capacity range; and if the first difference value is not within the first preset capacity range, determining that the self-discharge state of the single cell corresponding to the second dQ / dV capacity curve is abnormal self-discharge.

[0013] In some embodiments, the self-discharge state of the battery pack is determined according to the second difference value, which includes: determining whether the second difference value is within a second preset capacity range; and if the second difference value is not within the second preset capacity range, determining that the self-discharge state of the single cell corresponding to the third dQ / dV capacity curve is abnormal self-discharge.

[0014] In some embodiments, the self-discharge status of the battery pack is determined according to the SOC deviation value, which includes: determining whether the third difference value is within a third preset capacity range; and determining that the self-discharge status of the single cell corresponding to the second dQ / dV capacity curve is abnormal self-discharge if the third difference value is not within the third preset capacity range.

[0015] In some embodiments, the method further includes: determining that the self-discharge status of the battery pack is normal self-discharge when it is determined that the first differential value is within a first preset capacity range, the second differential value is within a second preset capacity range, and the third differential value is within a third preset capacity range.

[0016] An embodiment according to a second aspect of the present disclosure provides a vehicle, the vehicle including at least one processor and a memory communicatively coupled to the at least one processor, the memory storing a computer program executable by the at least one processor, wherein execution of the computer program by the at least one processor implements the method for detecting a self-discharge state of a battery pack in the above embodiment.

[0017] According to the vehicle of the embodiment of the present disclosure, by adopting the method for detecting the self-discharge state of the battery pack provided in the above embodiment, it is possible to realize detection of the self-discharge state of a single cell in the battery pack.

[0018] An embodiment according to a third aspect of the present disclosure provides a computer storage medium having a computer program stored thereon, the computer program being configured to, when executed by a processor, implement the method for detecting a self-discharge state of a battery pack in the above embodiment.

[0019] Additional aspects and advantages of the present disclosure will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the present disclosure.

[0020] The above and / or additional aspects and advantages of the present disclosure will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings. [Brief explanation of the drawings]

[0021] [Figure 1]1 is a flowchart of a method for detecting a self-discharge condition of a battery pack according to an embodiment of the present disclosure. [Figure 2] 1 is a flowchart of a method for detecting a self-discharge condition of a battery pack according to another embodiment of the present disclosure. [Figure 3] FIG. 1 is a structural block diagram of a vehicle according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] The embodiments described with reference to the accompanying drawings are exemplary and the embodiments of the present disclosure are described in detail below.

[0023] To solve the above problem, an embodiment according to a first aspect of the present disclosure provides a method for detecting a self-discharge state of a battery pack, and by using this method, the self-discharge state of a single cell in the battery pack can be detected.

[0024] A method for detecting a self-discharge state of a battery pack according to an embodiment of the present disclosure will be described with reference to FIG. 1, and as shown in FIG. 1, the method includes at least steps S1 to S4.

[0025] In step S1, charge and discharge data of each single cell of the battery pack is obtained.

[0026] In an embodiment, during the charging and discharging process of the battery pack, the charging and discharging data such as current, voltage, temperature, or SOC of each single cell will also change accordingly, so that the battery manager corresponding to the battery pack monitors the charging and discharging data of each single cell of the battery pack in real time during use, and uploads the detected charging and discharging data to a cloud server for subsequent retrieval and use.

[0027] In step S2, a dQ / dV capacity curve for each single cell is generated according to the charge and discharge data. That is, a dQ / dV capacity curve corresponding to each single cell is drawn using the charge and discharge data. For example, if the number of single cells in the battery pack is N, each single cell corresponds to a dQ / dV capacity curve, that is, the total number of dQ / dV capacity curves is N.

[0028] In some embodiments, after generating a dQ / dV capacity curve for each single cell according to the charge and discharge data, the SOC value of each single cell at the initial time of entering the charge / discharge phase is calculated. According to the nominal capacity value and SOC value of each single cell, denoted as Qn, the initial capacity value of each single cell at the initial time of entering the charge / discharge phase is calculated, using the formula: initial capacity value = Qn * SOC value. Furthermore, after entering the charge / discharge phase, as the usage time changes, the capacity value of each single cell changes based on the initial capacity value. For example, the capacity value gradually increases in the charge phase and gradually decreases in the discharge phase. In this process, the capacity increment of each single cell at each time is calculated, where capacity increment = current * interval time. The real-time capacity value of each single cell during the charge / discharge phase is calculated according to the initial capacity value and capacity increment. Specifically, the capacity value at the current time is calculated by adding the capacity increment to the capacity value at the previous time, thereby calculating the real-time capacity value at each time. The real-time voltage value of each single cell in the charge / discharge phase is obtained, and a dQ / dV capacity curve of each single cell is generated according to the initial capacity value, the real-time capacity value, and the real-time voltage value. Specifically, the capacity-voltage curve of each single cell can be drawn according to the initial capacity value, the real-time capacity value, and the real-time voltage value corresponding to each time. The capacity-voltage curve is smoothed and filtered, and the difference between the voltage and the capacity is calculated to obtain the dQ / dV capacity curve of each single cell.

[0029] In an embodiment, before using the charge / discharge data to plot the dQ / dV capacity curve, the acquired charge / discharge data is cleaned to screen and remove abnormal or missing data caused by hardware failures, communication failures such as network disconnections, or analysis errors, and the data is sorted in chronological order, i.e., sorted in ascending order of the data generation time, thereby simultaneously eliminating data streams, reducing data redundancy, and improving detection efficiency.

[0030] In step S3: the voltage inflection point characteristic information is determined according to the dQ / dV capacity curve of each single cell.

[0031] In an embodiment, the voltage-capacity curve of the battery pack includes three areas characterized by relatively slow voltage changes, hereinafter referred to as voltage plateaus.

[0032] The area characterized by relatively steep voltage changes lies between the two voltage plateaus, and the point within the area with the largest rate of change is called a voltage inflection point. Voltage inflection points are distinguished by voltage level, with relatively high voltages being called high-voltage inflection points (HVTP) and relatively low voltages being called low-voltage inflection points (LVTP). In practical applications, it is necessary to distinguish between the high-voltage inflection points and low-voltage inflection points for each cell. According to the above, the voltage inflection point characteristic information for each single cell is determined by the dQ / dV capacity curve, and the voltage inflection point characteristic information includes at least the locations of the inflection points, the voltage values ​​corresponding to the inflection points, and the capacitance values ​​corresponding to the inflection points.

[0033] In step S4, the self-discharge state of the battery pack is determined according to the voltage inflection point characteristic information.

[0034] Specifically, because a battery pack is composed of multiple individual cells connected in series, the current in the series circuit is equal everywhere during AC charging or discharging. Therefore, the change in the SOC value of each individual cell at each time is theoretically the same. Therefore, in the same battery pack, the actual SOC value corresponding to the voltage inflection point of each individual cell is also the same. Accordingly, it can be clearly seen that the difference in the position of the voltage inflection point of a battery pack during use can represent the difference in the actual SOC value of each individual cell, and the self-discharge status of each individual cell can also be determined. Therefore, in the present disclosure, a dQ / dV capacity curve of each individual cell is generated using charge and discharge data of each individual cell of the battery pack during use, and voltage inflection point characteristic information of each individual cell is determined according to the dQ / dV capacity curve of each individual cell. The self-discharge status of the battery pack is determined through the difference in the voltage inflection point characteristic information of each individual cell, thereby detecting the self-discharge status of each individual cell in the battery pack. Furthermore, the application scenario of this method is not limited, and this method may be applied to detecting the self-discharge status of a battery pack throughout its life cycle, and has wide applicability.

[0035] In an embodiment of the present disclosure, according to a method for detecting a self-discharge state of a battery pack, a dQ / dV capacity curve of each single cell is generated by using charge and discharge data of each single cell of the battery pack during use, and voltage inflection point characteristic information of each single cell is determined according to the dQ / dV capacity curve of each single cell, thereby determining the self-discharge state of the battery pack through the difference between the voltage inflection point characteristic information of each single cell, thereby realizing detection of the self-discharge situation of each single cell in the battery pack, further, the application scenario of this method is not limited, and this method may be applied to detecting the self-discharge state of a battery pack throughout its entire life cycle, and has wide applicability.

[0036] In some embodiments, the voltage inflection point characteristic information is determined according to the dQ / dV capacity curve of each single cell, which includes: determining, among all the dQ / dV capacity curves, a first dQ / dV capacity curve in which a high-voltage inflection point occurs earliest, a second dQ / dV capacity curve in which a high-voltage inflection point occurs latest, and a third dQ / dV capacity curve in which a low-voltage inflection point occurs latest; determining, according to the first dQ / dV capacity curve, a first capacitance value corresponding to a first high-voltage inflection point, i.e., a high-voltage peak value, in the first dQ / dV capacity curve; determining, according to the second dQ / dV capacity curve, a second capacitance value corresponding to a second high-voltage inflection point, i.e., a high-voltage peak value, in the second dQ / dV capacity curve; and determining, according to the third dQ / dV capacity curve, a third capacitance value corresponding to a low-voltage inflection point, i.e., a low-voltage peak value, in the third dQ / dV capacity curve.

[0037] In some embodiments, the self-discharge state of the battery pack is determined according to the voltage inflection point characteristic information of each single cell, which includes: determining a first difference value between the second capacity value and the first capacity value, and determining the self-discharge state of the battery pack according to the first difference value (i.e., subtracting the first capacity value Q1 corresponding to the earliest occurrence of HVTP in the charge / discharge phase from the second capacity value Q2 corresponding to the latest occurrence of HVTP (i.e., the first difference ΔQ1=Q2−Q1), and determining the self-discharge state of the battery pack according to the calculated first difference value); and / or A second difference value between the first capacitance value and the third capacitance value is calculated, and the self-discharge state of the battery pack is determined according to the second difference value (i.e., the third capacitance value Q3 corresponding to the latest occurrence of LVTP in the charge / discharge phase is subtracted from the first capacitance value Q1 corresponding to the earliest occurrence of HVTP (i.e., the second difference ΔQ2=Q1-Q3), and the self-discharge state of the battery pack is determined according to the calculated second difference value); and / or A theoretical capacity value of the single cell corresponding to the third high-voltage inflection point on the theoretical dQ / dV capacity curve is determined (wherein the theoretical dQ / dV capacity curve may be understood as a curve theoretically formed by each single cell according to changes in capacity and voltage before the battery pack is put into practical application, and accordingly, the theoretical capacity value may be understood as the capacity value of each single cell theoretically corresponding to the high-voltage inflection point when no abnormal self-discharge situation occurs). A third difference value between the second capacity value Q2 and the theoretical capacity value Q_HVTP is determined (i.e., the second capacity value Q2 corresponding to the latest occurrence of HVTP in the charge / discharge phase is subtracted from the theoretical capacity value of the single cell corresponding to the high-voltage inflection point (i.e., the third difference value Q3=Q_HVTP−Q2)), and the self-discharge state of the battery pack is determined according to the third difference value.

[0038] It should be noted that when the battery pack is in use, if the usage time is short, a voltage inflection point may not occur. Therefore, in actual use, depending on the actual situation, the self-discharge state of the battery pack may be determined by any one of the first differential value, the second differential value, and the third differential value, or by any two of these, or the self-discharge state of the battery pack may be determined from the above three perspectives simultaneously, and is not limited to this.

[0039] In some embodiments, it is determined whether the first difference value is within a first preset capacity range; if it is not within the range, i.e., if the first difference value is not within the first preset capacity range, this means that the difference value between the first capacitance value Q1 corresponding to the earliest occurrence of HVTP and the second capacitance value Q2 corresponding to the latest occurrence of HVTP is too large, and it is determined that the single cell corresponding to the latest occurrence of HVTP has a self-discharge situation, i.e., the self-discharge state of the single cell corresponding to the second dQ / dV capacity curve is abnormal self-discharge.

[0040] In some embodiments, it is determined whether the second difference value is within a second preset capacity range; if it is not within the range, i.e., if the second difference value is not within the second preset capacity range, this means that the difference value between the first capacitance value Q1 corresponding to the earliest occurrence of HVTP and the third capacitance value Q3 corresponding to the latest occurrence of LVTP is too small, and the single cell corresponding to the latest occurrence of LVTP has a self-discharge situation, i.e., the self-discharge state of the single cell corresponding to the third dQ / dV capacity curve is determined to be abnormal self-discharge.

[0041] In some embodiments, it is determined whether the third difference value is within a third preset capacity range; if it is not within the range, i.e., if the third difference value is not within the third preset capacity range, this means that the second capacitance value Q2 corresponding to the latest occurrence of HVTP does not match the capacitance value theoretically corresponding to the latest occurrence of HVTP, and therefore the self-discharge state of the single cell corresponding to the second dQ / dV capacity curve is determined to be abnormal self-discharge.

[0042] In some embodiments, when the self-discharge state of the battery pack is determined simultaneously by the first differential value, the second differential value, and the SOC deviation value, unless any of them satisfies the preset range, this means that the battery pack has an abnormal self-discharge situation; when it is determined that the first differential value is within the first preset capacity range, the second differential value is within the second preset capacity range, and the third differential value is within the third preset capacity range, the self-discharge state of the battery pack is determined to be normal self-discharge.

[0043] In some embodiments, the first preset capacity range, the second preset capacity range, and the third preset capacity range are values ​​that are predetermined according to the actual characteristics of a single cell during factory testing, and are not limited to these.

[0044] In some embodiments, the present disclosure can provide an early warning prompt when abnormal self-discharge of a single cell is detected to notify the user of the fault in advance and avoid an accident.

[0045] A method for detecting a self-discharge state of a battery pack according to an embodiment of the present disclosure is described as an example with reference to FIG. 2 , and the specific steps are as follows, where the battery pack is in a charging phase as an example:

[0046] In step S5, the charge and discharge data is cleaned and sorted.

[0047] In step S6, the charging data of the battery pack in the charging phase is selected, and the data of the charging phase is merged.

[0048] In step S7, a first capacitance value, a second capacitance value, and a third capacitance value are determined according to the dQ / dV capacitance curve of each single cell.

[0049] In step S8, the first difference value, the second difference value, and the third difference value are calculated.

[0050] In step S9, it is determined whether the first difference value, the second difference value, or the third difference value exceeds the corresponding preset range. If the first difference value, the second difference value, or the third difference value exceeds the corresponding preset range, step S10 is executed. If none of the first difference value, the second difference value, or the third difference value exceeds the corresponding preset range, step S11 is executed.

[0051] In step S10, the self-discharge state of the battery pack is determined to be abnormal self-discharge.

[0052] In step S11, the self-discharge state of the battery pack is determined to be normal self-discharge.

[0053] In summary, in an embodiment of the present disclosure, according to the method for detecting the self-discharge state of a battery pack, a dQ / dV capacity curve corresponding to each individual cell is generated based on the charge and discharge data of all individual cells during the use of the battery pack, and voltage inflection point characteristic information is determined by analyzing the curve characteristics, thereby allowing the entire life cycle of the battery pack to be monitored. Furthermore, this method is not limited to the factory stage of the cells, does not require long-term storage of the battery pack, and does not require judgment according to different vehicle models and aging levels. Therefore, the application scenario of the present disclosure is not limited, has a wide range of use, and is in line with user habits, making it easy for users to grasp the self-discharge state of the battery pack at any time.

[0054] An embodiment of a second aspect of the present disclosure provides a vehicle, and as shown in FIG. 3, the vehicle 10 includes at least one processor 1 and a memory 2 communicatively coupled to the at least one processor 1.

[0055] Here, the memory 2 stores a computer program that can be executed by at least one processor 1, and when the at least one processor 1 executes the computer program, the method for detecting a self-discharge state of a battery pack in the above embodiment is implemented.

[0056] It should be noted that in the embodiment of the present disclosure, the specific implementation of the vehicle 10 is similar to the specific implementation of the method for detecting a self-discharge state of a battery pack in any of the above embodiments of the present disclosure, for details, please refer to the description in the method section, and the description will not be repeated here to reduce redundancy.

[0057] According to the vehicle 10 in the embodiment of the present disclosure, by adopting the method for detecting the self-discharge state of the battery pack provided in the above embodiment, the self-discharge state of a single cell in the battery pack can be detected.

[0058] An embodiment of a third aspect of the present disclosure provides a computer storage medium having a computer program stored thereon, the computer program, when executed by a processor, realizing the method for detecting a self-discharge state of a battery pack in the above embodiment.

[0059] In the description herein, descriptions of processes or methods illustrated in flowcharts or otherwise described herein may be understood to represent modules, segments, or portions of code that include one or more executable instructions for implementing customized logical functions or process steps, and the scope of preferred embodiments of the present disclosure includes additional implementations in which functions may be performed out of the order shown or discussed, including in a substantially simultaneous manner or in reverse order depending on the functions involved, as should be understood by one skilled in the art to which embodiments of the present disclosure pertain.

[0060] The logic and / or steps represented in flowcharts or otherwise described herein may be thought of as, for example, a defined sequence of executable instructions for implementing logical functions and may be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, a system including a processor, or other system capable of fetching and executing instructions from an instruction execution system, apparatus, or device. For purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic devices), a portable computer cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disk read-only memory (CD-ROM). In addition, the computer-readable medium may be paper or other suitable medium on which the program may be printed, since the program may be obtained electronically, for example by optical scanning of paper or other medium, followed by editing, interpretation, or processing in any other suitable manner as required, and then stored in computer memory.

[0061] It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, steps or methods may be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, in another embodiment, when implemented in hardware, it may be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application specific integrated circuits having appropriate combinatorial logic gates, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0062] Those skilled in the art will understand that all or part of the steps involved in implementing the methods of the above embodiments may be achieved by instructing relevant hardware by a program stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0063] In addition, in each embodiment of the present application, each functional unit may be integrated into one processing module, each unit may exist physically alone, or two or more units may be integrated into one module. The integrated module may be implemented in the form of a hardware or software functional module. When the integrated module is implemented as a software functional module and sold or used as a standalone product, it may be stored in a computer-readable storage medium.

[0064] The storage medium mentioned above may be a read-only memory, a magnetic disk, an optical disk, etc. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are illustrative and should not be understood as limitations of the present application, and that those skilled in the art may make changes, modifications, substitutions, or alterations to the above embodiments within the scope of the present application.

[0065] In the description herein, a description that refers to terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "particular examples," or "some examples" means that the particular feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present application. In this description, general references to such terms do not necessarily refer to the same embodiment or example.

[0066] While embodiments of the present application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the claims and their equivalents. [Explanation of symbols]

[0067] 1 processor 2. Memory 10 vehicles

Claims

1. 1. A method for detecting a self-discharge condition of a battery pack, comprising: Obtaining charge and discharge data of each single cell of the battery pack (S1); generating a dQ / dV capacity curve for each single cell according to the charge and discharge data (S2); determining voltage inflection point characteristic information according to the dQ / dV capacity curve of each single cell (S3); determining the self-discharge state of the battery pack according to the voltage inflection point characteristic information (S4); 1. A method for detecting a self-discharge condition of a battery pack, comprising:

2. generating a dQ / dV capacity curve for each single cell according to the charge and discharge data (S2); Determining the SOC value of each single cell at an initial time when the charge / discharge phase begins; Obtaining an initial capacity value of each single cell at an initial time of charging / discharging according to the nominal capacity value of each single cell and the SOC value; After entering the charge / discharge phase, determining the capacity increment of each single cell at each time; determining a real-time capacity value of each single cell in the charge / discharge phase according to the initial capacity value and the capacity increment; determining a real-time voltage value of each single cell during the charge / discharge phase; generating the dQ / dV capacity curve of each single cell according to the initial capacity value, the real-time capacity value, and the real-time voltage value; 10. The method for detecting a self-discharge condition of a battery pack according to claim 1, comprising:

3. determining voltage inflection point characteristic information according to the dQ / dV capacity curve of each single cell (S3); Among all the dQ / dV capacity curves, a first dQ / dV capacity curve in which a high-voltage inflection point occurs earliest, a second dQ / dV capacity curve in which the high-voltage inflection point occurs latest, and a third dQ / dV capacity curve in which a low-voltage inflection point occurs latest are obtained; determining a first capacitance value according to the first dQ / dV capacitance curve, the first capacitance value corresponding to a first high voltage inflection point on the first dQ / dV capacitance curve; determining a second capacitance value according to the second dQ / dV capacitance curve, the second capacitance value corresponding to a second high voltage inflection point on the second dQ / dV capacitance curve; determining a third capacitance value corresponding to a low voltage inflection point on the third dQ / dV capacitance curve according to the third dQ / dV capacitance curve; 3. The method for detecting a self-discharge state of a battery pack according to claim 1, comprising:

4. determining the self-discharge state of the battery pack according to the voltage inflection point characteristic information (S4); determining a first difference value between the second capacitance value and the first capacitance value; determining the self-discharge state of the battery pack according to the first difference value; and / or determining a second difference value between the first capacitance value and the third capacitance value; determining the self-discharge state of the battery pack according to the second difference value; and / or determining a theoretical capacity value of the single cell corresponding to a third high voltage inflection point in a theoretical dQ / dV capacity curve; determining a third difference value between the second capacitance value and the theoretical capacitance value; determining the self-discharge state of the battery pack according to the third difference value; 4. The method for detecting a self-discharge condition of a battery pack according to claim 3, comprising:

5. determining the self-discharge state of the battery pack according to the first difference value; determining whether the first difference value is within a first preset volume range; If the first difference value is not within the first preset capacity range, determining that the self-discharge state of the single cell corresponding to the second dQ / dV capacity curve is abnormal self-discharge; 5. The method for detecting a self-discharge condition of a battery pack according to claim 4, comprising:

6. determining the self-discharge state of the battery pack according to the second difference value; determining whether the second difference value is within a second preset volume range; If the second difference value is not within the second preset capacity range, determining that the self-discharge state of the single cell corresponding to the third dQ / dV capacity curve is abnormal self-discharge; 6. The method for detecting a self-discharge state of a battery pack according to claim 4 or 5, comprising:

7. determining the self-discharge state of the battery pack according to an SOC deviation value, determining whether the third difference value is within a third preset volume range; If the third difference value is not within the third preset capacity range, determining that the self-discharge state of the single cell corresponding to the second dQ / dV capacity curve is abnormal self-discharge; 7. A method for detecting a self-discharge state of a battery pack according to claim 4, comprising:

8. When it is determined that the first difference value is within the first preset capacity range, the second difference value is within the second preset capacity range, and the third difference value is within the third preset capacity range, it is determined that the self-discharge state of the battery pack is normal self-discharge. The method for detecting a self-discharge state of a battery pack according to any one of claims 4 to 7, further comprising:

9. At least one processor (1); a memory (2), the memory being communicatively coupled to the at least one processor (1), a computer program being stored in the memory (2) and executable by the at least one processor (1), the method for detecting a self-discharge state of a battery pack according to any one of claims 1 to 8 being performed when the at least one processor (1) executes the computer program; A vehicle (10) comprising:

10. A computer storage medium storing a computer program which, when executed by a processor, implements the method for detecting a self-discharge state of a battery pack according to any one of claims 1 to 8.

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