Battery cell self-discharge rate detection method and device, storage medium and program product

Abstract

The embodiment of the invention provides a detection method and device for the self-discharge rate of a battery cell, a storage medium and a program product, and relates to the technical field of batteries. The method for detecting the self-discharge rate of the battery cell comprises the steps of determining a first SOC difference value between an SOC value of the battery cell of a battery and an SOC value of a reference battery cell under the condition that a first detection condition is met; under the condition that a second detection condition is met, determining a second SOC difference value between the SOC value of the battery cell and the SOC value of the reference battery cell and a balanced SOC; based on the first SOC difference value, the second SOC difference value and the balanced SOC, determining self-discharge difference information of the battery cell; and determining the self-discharge rate of the battery cell according to the self-discharge rate test value of the battery cell and the self-discharge difference information of all the battery cells of the battery, or according to the self-discharge rate test value of the battery cell. The detection accuracy and reliability of the self-discharge rate of the battery cell are improved, the stability and safety of battery cell operation can be improved, the performance of the battery cell is improved, and the service life of the battery cell is prolonged.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, storage medium and computer program product for detecting the self-discharge rate of a battery cell. Background Art

[0002] The self-discharge rate of a battery cell refers to the rate at which the charge decreases by itself due to various physical and chemical processes inside the battery cell when the battery cell is in an open circuit state. The self-discharge rate of a battery cell can characterize the ability of the battery cell to maintain charge during storage. The battery cell will self-discharge during the process of storing electric energy. The self-discharge rate is one of the important indicators for evaluating battery performance, which is directly related to the storage performance and service life of the battery. At present, the existing methods for detecting the self-discharge rate of a battery cell include the open circuit voltage (OCV) measurement method and other methods. The open circuit voltage measurement method determines the self-discharge rate of a battery cell by directly measuring the change in the open circuit voltage during the static state of the battery. Since the change in the OCV of a battery cell is usually not only caused by the self-discharge phenomenon, the existing methods for detecting the self-discharge rate of a battery cell do not take into account the actual balance of the battery cell. Therefore, the detected self-discharge rate is not accurate enough, which poses a safety hazard to the use of the battery. Summary of the invention

[0003] In view of the above problems, the present application provides a method, device, storage medium and computer program product for detecting the self-discharge rate of a battery cell, so as to improve the accuracy and reliability of detecting the self-discharge rate of a battery cell.

[0004] According to a first aspect of the present disclosure, a method for detecting a self-discharge rate of a battery cell is provided, comprising: determining a first SOC difference between an SOC value of a battery cell of a battery and an SOC value of a reference battery cell of the battery when a first detection condition is met; determining a second SOC difference between the SOC value of the battery cell and the SOC value of the reference battery cell of the battery, and a balanced SOC of the battery cell relative to the reference battery cell of the battery when a second detection condition is met; determining self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC; determining the self-discharge rate of the battery cell according to a self-discharge rate test value of the battery cell, the self-discharge difference information of all the batteries of the battery, or according to the self-discharge rate test value of the battery cell.

[0005] In this embodiment, the first SOC difference between the battery cell and the reference battery cell is determined when the first detection condition is met, and the second SOC difference between the battery cell and the reference battery cell and the balanced SOC are determined when the second detection condition is met, so as to determine the self-discharge difference information of the battery cell, and determine the self-discharge rate of the battery cell according to the self-discharge rate test value of the battery cell and the self-discharge difference information of all the battery cells; the self-discharge difference information of the battery cell can be determined based on the charge state difference of the battery cell and the actual balanced information, the self-discharge difference information of the battery cell can be dynamically determined and the self-discharge rate of the battery cell can be determined in combination with the self-discharge rate test value of the battery cell, thereby improving the accuracy and reliability of the self-discharge rate detection of the battery cell, being able to reasonably control the charging and discharging process of the battery cell to avoid the occurrence of overcharging, over-discharging, etc. of the battery cell, improving the stability and safety of the battery cell operation, and improving the performance and service life of the battery cell, and the detection method is easy to implement.

[0006] In some embodiments, the battery cell self-discharge rate includes: the maximum self-discharge rate of the battery cell; determining the battery cell self-discharge rate according to the battery cell self-discharge rate test value and the self-discharge difference information of all the battery cells of the battery includes: determining the maximum self-discharge difference information and the minimum self-discharge difference information according to the self-discharge difference information of all the battery cells; determining the maximum self-discharge rate of the battery cell according to the maximum self-discharge difference information, the minimum self-discharge difference information and the battery cell self-discharge rate test value.

[0007] In this embodiment, the maximum self-discharge difference information and the minimum self-discharge difference information of the battery cells are determined through the self-discharge difference information of all the battery cells, and the maximum self-discharge rate of the battery cells is determined in combination with the self-discharge rate test value of the battery cells, thereby improving the accuracy and reliability of the maximum self-discharge rate detection of the battery cells, and can improve the stability and safety of the battery cell operation, and enhance the performance and service life of the battery cells.

[0008] In some embodiments, determining the maximum self-discharge rate of the battery cell based on the maximum self-discharge difference information, the minimum self-discharge difference information and the battery cell self-discharge rate test value includes: calculating a first difference between the maximum self-discharge difference information and the minimum self-discharge difference information; and taking the sum of the first difference and the battery cell self-discharge rate test value as the maximum self-discharge rate of the battery cell.

[0009] In this embodiment, the difference between the maximum self-discharge difference information and the minimum self-discharge difference information and the sum of the cell self-discharge rate test value are used as the cell maximum self-discharge rate, thereby improving the accuracy and reliability of the cell maximum self-discharge rate detection.

[0010] In some embodiments, the battery cell self-discharge rate includes: an average self-discharge rate of the battery cell; determining the battery cell self-discharge rate according to a battery cell self-discharge rate test value and self-discharge difference information of all the battery cells of the battery includes: determining maximum self-discharge difference information, minimum self-discharge difference information and the number of battery cells of all the battery cells according to the self-discharge difference information of all the battery cells; determining the average self-discharge rate of the battery cell according to the maximum self-discharge difference information, the minimum self-discharge difference information, the number of battery cells and the battery cell self-discharge rate test value.

[0011] In this embodiment, the maximum self-discharge difference information and the minimum self-discharge difference information of the battery cells and the number of battery cells are determined based on the self-discharge difference information of all battery cells, and the average self-discharge rate of the battery cells is determined in combination with the self-discharge rate test value of the battery cells. This improves the accuracy and reliability of the detection of the average self-discharge rate of the battery cells, can improve the stability and safety of the battery cell operation, and improve the performance and service life of the battery cells.

[0012] In some embodiments, determining the average self-discharge rate of the battery cells based on the maximum self-discharge difference information, the minimum self-discharge difference information, the number of battery cells and the battery cell self-discharge rate test value includes: calculating a second difference between the maximum self-discharge difference information and the minimum self-discharge difference information; calculating a quotient of the second difference and the number of battery cells; and taking the sum of the quotient and the battery cell self-discharge rate test value as the average self-discharge rate of the battery cells.

[0013] In this embodiment, by calculating the quotient of the difference between the maximum self-discharge difference information and the minimum self-discharge difference information and the number of battery cells, the sum of this quotient and the battery cell self-discharge rate test value is used as the average battery cell self-discharge rate, thereby improving the accuracy and reliability of the average battery cell self-discharge rate detection.

[0014] In some embodiments, the battery cell self-discharge rate includes: a minimum battery cell self-discharge rate; and determining the battery cell self-discharge rate according to the battery cell self-discharge rate test value includes: using the battery cell self-discharge rate test value as the minimum battery cell self-discharge rate.

[0015] In this embodiment, the minimum self-discharge rate of the battery cell is determined by the self-discharge rate test value of the battery cell, which can improve the accuracy of the minimum self-discharge rate of the battery cell, improve the stability and safety of the battery cell operation, and enhance the performance and service life of the battery cell.

[0016] In some embodiments, determining the balanced SOC of the battery cell relative to a reference battery cell of the battery includes: determining a cumulative time difference of equalization of the battery cell relative to a reference battery cell of the battery and a balanced current of the battery cell during a time period from the moment when the first detection condition is satisfied to the moment when the second detection condition is satisfied; obtaining the rated capacity and the state of health SOH of the battery cell; and determining the balanced SOC based on the cumulative time difference of equalization, the balanced current, the rated capacity and the SOH.

[0017] In this embodiment, the balanced SOC is determined by the balanced accumulated time difference, balanced current, rated capacity and SOH of the battery cell relative to the reference battery cell, thereby improving the accuracy and reliability of the determined self-discharge difference information.

[0018] In some embodiments, determining the self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC includes: calculating a third difference between the second SOC difference and the first SOC difference; and determining the self-discharge difference information based on the sum of the third difference and the balanced SOC.

[0019] In this embodiment, the self-discharge difference information is determined by calculating the sum of the difference between the second SOC difference and the first SOC difference and the balanced SOC, thereby improving the accuracy and reliability of the determined self-discharge difference information, thereby improving the accuracy of the detected battery cell self-discharge rate.

[0020] In some embodiments, when determining the reference cell of the battery, a cell with the smallest SOC value is determined from all the cells of the battery as the reference cell of the battery.

[0021] In this embodiment, the accuracy of the detected self-discharge rate of the battery cell can be improved by determining the battery cell with the smallest SOC value from all the battery cells as the reference battery cell of the battery.

[0022] In some embodiments, the self-discharge rate test value of the battery cell is determined according to the self-discharge rate test information of the battery.

[0023] In this embodiment, the self-discharge rate test value of the battery cell is determined based on the self-discharge rate test information of the battery, thereby improving the efficiency and accuracy of determining the self-discharge rate test value of the battery cell.

[0024] In some embodiments, the first detection condition includes: the SOC values ​​of all the cells of the battery are less than an SOC threshold, and all the cells are in a stationary state.

[0025] In some embodiments, the second detection condition includes: the SOC values ​​of all the battery cells are less than the SOC threshold, all the battery cells are in a stationary state, and the self-discharge rate calculation cumulative time is greater than the time threshold; wherein the self-discharge rate calculation cumulative time includes: the first cumulative time or the second cumulative time; the first cumulative time includes: the time period between the current moment and the moment when the first detection condition is met; the second cumulative time includes: the time period between the last time the battery was synchronized and the production date of the battery.

[0026] The battery cell detection method of the embodiment of the present application can ensure the accuracy of determining information such as the charge state difference and actual balancing information of the battery cells by setting the first detection condition and the second detection condition, and can monitor the self-discharge state of the battery and determine the self-discharge rate of the battery cell during long-term power outage and storage.

[0027] In some embodiments, according to the second aspect of the present disclosure, a device for detecting the self-discharge rate of a battery cell is provided, comprising: a first information acquisition module, for determining a first SOC difference between the SOC value of a battery cell and the SOC value of a reference battery cell of the battery when a first detection condition is met; a second information acquisition module, for determining a second SOC difference between the SOC value of the battery cell and the SOC value of the reference battery cell of the battery, and a balanced SOC of the battery cell relative to the reference battery cell of the battery when a second detection condition is met; a difference information determination module, for determining the self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC; a self-discharge rate determination module, for determining the self-discharge rate of the battery cell according to a battery cell self-discharge rate test value, the self-discharge difference information of all the batteries of the battery, or the battery cell self-discharge rate test value.

[0028] In this embodiment, the first SOC difference between the battery cell and the reference battery cell is determined when the first detection condition is met, and the second SOC difference between the battery cell and the reference battery cell and the balanced SOC are determined when the second detection condition is met, so as to determine the self-discharge difference information of the battery cell, and determine the self-discharge rate of the battery cell according to the self-discharge rate test value of the battery cell and the self-discharge difference information of all the battery cells; the self-discharge difference information of the battery cell can be determined based on the charge state difference of the battery cell and the actual balanced information, the self-discharge difference information of the battery cell can be dynamically determined and the self-discharge rate of the battery cell can be determined in combination with the self-discharge rate test value of the battery cell, thereby improving the accuracy and reliability of the self-discharge rate detection of the battery cell, being able to reasonably control the charging and discharging process of the battery cell to avoid the occurrence of overcharging, over-discharging, etc. of the battery cell, improving the stability and safety of the battery cell operation, and improving the performance and service life of the battery cell, and the detection method is easy to implement.

[0029] In some embodiments, according to a third aspect of the present disclosure, a device for detecting a self-discharge rate of a battery cell is provided, comprising: a memory; and a processor coupled to the memory, wherein the processor is configured to execute the method as described above based on instructions stored in the memory.

[0030] In some embodiments, according to a fourth aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the instructions are executed by a processor as described above.

[0031] In some embodiments, according to a fifth aspect of the present disclosure, a computer program product is provided, wherein the computer program product stores computer instructions, and the instructions are executed by a processor as described above.

[0032] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described in the following are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0034] Figure 1 Schematic diagram of the flow of some embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention; Figure 2 It is a schematic diagram of a flow chart of determining a balanced SOC in some embodiments of the method for detecting a self-discharge rate of a battery cell disclosed in the present invention; Figure 3 It is a schematic diagram of a process of determining the self-discharge difference information of a battery cell in some embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention; Figure 4 A schematic diagram of a process for determining a self-discharge rate of a battery cell in some embodiments of the method for detecting a self-discharge rate of a battery cell disclosed herein; Figure 5 A schematic diagram of a flow chart of determining a self-discharge rate of a battery cell in other embodiments of the method for detecting a self-discharge rate of a battery cell disclosed in the present invention; Figure 6 Schematic diagram of modules of some embodiments of the battery cell self-discharge rate detection device disclosed in the present invention; Figure 7Schematic diagrams of modules of other embodiments of the device for detecting the self-discharge rate of a battery cell disclosed in the present invention; Figure 8 Schematic diagram of modules of some other embodiments of the device for detecting the self-discharge rate of a battery cell disclosed in the present invention. DETAILED DESCRIPTION

[0035] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0037] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0038] Reference to "embodiments" herein means that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least some embodiments of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0040] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0041] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0042] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0043] Figure 1 Schematic diagram of some embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention. Figure 1 As shown, the method for detecting the self-discharge rate of the battery cell includes steps S101 to S104: Step S101 : determining a first SOC difference between an SOC value of a battery cell of a battery and an SOC value of a reference battery cell of the battery when a first detection condition is met.

[0044] The battery can be a variety of batteries such as lithium batteries; the battery includes a cell, which can be a variety of cells such as lithium cells, and the cell is used to store electricity. The battery can collect various data such as voltage and current of each cell through existing devices; when the first detection condition is met, the SOC (State of Charge) value of each cell of the battery is determined. The SOC value of the battery cell can be determined using a variety of methods. For example, the SOC value of the battery cell is determined based on the SOC-OCV (Open Circuit Voltage) curve of the battery cell and the voltage of the battery cell.

[0045] A variety of methods may be used to determine a reference cell among all the cells of the battery; after determining the reference cell, a first SOC difference between the SOC value of the cell of the battery and the SOC value of the reference cell of the battery is determined.

[0046] Step S102 , when the second detection condition is met, determining a second SOC difference between the SOC value of the battery cell and the SOC value of a reference battery cell of the battery, and a balanced SOC of the battery cell relative to the reference battery cell of the battery.

[0047] When the second detection condition is met, the SOC information of each battery cell of the battery is determined. A variety of methods can be used to determine the SOC value of the battery cell, for example, according to the SOC-OCV curve of the battery cell and based on the voltage of the battery cell, the SOC value of the battery cell is determined; a second SOC difference between the battery cell and the reference battery cell of the battery is determined, and the balanced SOC of the battery cell relative to the reference battery cell of the battery is determined. A variety of methods can be used to determine the balanced SOC of the battery cell relative to the reference battery cell of the battery.

[0048] Step S103, determining self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC.

[0049] Step S104, determining the cell self-discharge rate according to the cell self-discharge rate test value, the self-discharge difference information of all the cells of the battery, or according to the cell self-discharge rate test value.

[0050] The battery cell self-discharge rate table can be obtained by conducting laboratory tests on the battery cell; the battery cell self-discharge rate test value can be determined based on the battery cell self-discharge rate table.

[0051] The method for detecting the self-discharge rate of a battery cell disclosed in the present invention can determine the self-discharge difference information of the battery cell based on the charge state difference of the battery cell and the actual equalization information, can dynamically determine the self-discharge difference information of the battery cell and determine the self-discharge rate of the battery cell in combination with the self-discharge rate test value of the battery cell, thereby improving the accuracy and reliability of the self-discharge rate detection of the battery cell, and can reasonably control the charging and discharging process of the battery cell to avoid the occurrence of overcharging, over-discharging, etc. of the battery cell, can improve the stability and safety of the battery cell operation, and enhance the performance and service life of the battery cell, and the detection method is easy to implement.

[0052] In some embodiments, by setting the first detection condition and the second detection condition, the accuracy of information such as the charge state difference and actual balancing information of the battery cells can be ensured, and the self-discharge state of the battery can be monitored and the self-discharge rate of the battery cells can be determined during long-term power outage.

[0053] The first detection condition may be a plurality of detection conditions. For example, the first detection condition includes: the SOC values ​​of all cells of the battery are less than the SOC threshold, and all cells are in a stationary state. When the cells are in a stationary state, there is no charging current and no discharging current in the cells. The SOC threshold may be set, and the SOC threshold may be 25%, etc.

[0054] For example, after the battery controller is powered on at a low voltage, it is determined whether the first detection condition is met. If the SOC values ​​of all the battery cells are less than 25%, and all the battery cells have no charge or discharge current (are in a static state), it is determined that the first detection condition is met; when the first detection condition is met, the battery is in a low-end static state.

[0055] There are many methods for determining the reference cell of a battery. When determining the reference cell of a battery, the cell with the smallest SOC value can be determined from all the cells of the battery as the reference cell of the battery; by determining the cell with the smallest SOC value from all the cells of the battery as the reference cell of the battery, the accuracy of the detected cell self-discharge rate can be improved.

[0056] For example, when a first detection condition is met, a reference cell of the battery is determined; when determining the reference cell of the battery, a cell with the smallest SOC value can be determined from all the cells of the battery as the reference cell of the battery; a first SOC difference between the SOC value of each cell of the battery (including the reference cell) and the SOC value of the reference cell is calculated.

[0057] The second detection condition may be a variety of detection conditions. For example, the second detection condition includes: the SOC values ​​of all cells are less than the SOC threshold, all cells are in a stationary state, and the accumulated time for calculating the self-discharge rate is greater than the time threshold; wherein the accumulated time for calculating the self-discharge rate includes: the first accumulated time or the second accumulated time; the first accumulated time includes: the time period between the current moment and the moment when the first detection condition is met; the second accumulated time includes: the time period between the most recent battery synchronization moment and the battery production date; the battery synchronization moment may be the moment when the battery management system, etc. synchronizes the time of the cells.

[0058] For example, the time threshold can be set, such as 30 days, 40 days, etc. The first accumulated time is ΔT2, ΔT2 = T2-T1, where T2 is the current time and T1 is the time when the first SOC difference is determined, that is, the time when the first detection condition is met. The second accumulated time is ΔT1, and ΔT1 is the time period between the last battery synchronization time and the battery production date. For example, the battery production date is January 1, 2025, and the last battery synchronization time is February 8, 2025, then ΔT1 is 38 days.

[0059] When the second detection condition is met, the reference cell of the battery can be determined; or when the second detection condition is met, the reference cell of the battery may not be determined and the previously determined reference cell may be used. When determining the reference cell of the battery, the cell with the smallest SOC value may be determined from all the cells of the battery as the reference cell of the battery. The reference cell determined respectively when the first detection condition and the second detection condition are met is usually the same cell.

[0060] Whether the second detection condition is met can be determined periodically at intervals of a predetermined time. For example, when it is determined that the SOC values ​​of all cells are less than 25%, all cells are in a stationary state, and the first cumulative time is greater than 30 days, it is determined that the second detection condition is met. When the second detection condition is met, a second SOC difference between the SOC value of the cell and the SOC value of the reference cell is determined, as well as the balanced SOC of the cell relative to the reference cell.

[0061] Figure 2 FIG. 1 is a flow chart of determining the balanced SOC in some embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention, such as Figure 2 As shown: Step S201, determining the equalization accumulated time difference of the battery cell relative to the reference battery cell of the battery and the equalization current of the battery cell in a time period from the moment when the first detection condition is satisfied to the moment when the second detection condition is satisfied.

[0062] The moment when the first detection condition is met is the moment when the first SOC difference is determined; the moment when the second detection condition is met is the moment when the second SOC difference is determined; for example, the moment when the first detection condition is met is t1, the moment when the second detection condition is met is t2, and the time period from the moment when the first detection condition is met to the moment when the second detection condition is met is the time period between t2-t1.

[0063] The data recording and analysis function of the battery management system can be used to determine the cumulative equalization time difference of each cell relative to the reference cell of the battery, the equalization current of the cell, and other information during the time period from the moment when the first detection condition is met to the moment when the second detection condition is met. According to the equalization strategy, the battery management system can calculate the cumulative equalization time and equalization current of each cell during the time period from the moment when the first detection condition is met to the moment when the second detection condition is met; based on the cumulative equalization time of each cell and the cumulative equalization time of the reference cell, the cumulative equalization time difference of each cell relative to the reference cell of the battery can be determined; the equalization current of the cell is the current flowing through the equalization resistor of the cell during discharge equalization.

[0064] Step S202, obtaining the rated capacity and health state SOH of the battery cell.

[0065] There are many ways to obtain the rated capacity and health status (Stay Of Health, SOH) of the battery cell. For example, the rated capacity of the battery cell can be determined by querying the specification information of the battery cell; the voltage, current, temperature and other information of the battery cell during the charging and discharging process can be collected, and the SOH of the battery cell can be calculated based on a preset model.

[0066] Step S203, determining the balanced SOC according to the balanced accumulated time difference, balanced current, rated capacity and SOH.

[0067] For example, to calculate the balanced SOC of each cell relative to the reference cell of the battery: SOC_bal_n=T_bal_n*balancing current / (rated capacity*SOH) (1-1); Among them, SOC_bal_n is the balanced SOC of the nth battery cell relative to the reference battery cell of the battery; T_bal_n is the balanced cumulative time difference of the nth battery cell relative to the reference battery cell during the time period from the moment when the first detection condition is met to the moment when the second detection condition is met; the balanced current is the balanced current of the nth battery cell during the time period from the moment when the first detection condition is met to the moment when the second detection condition is met; the rated capacity is the rated capacity of the nth battery cell, for example, 280Ah; SOH is the SOH of the nth battery cell, which characterizes the degree of aging of the battery cell.

[0068] The balanced SOC is determined by the difference in the balanced cumulative time of the battery cell relative to the reference battery cell, the balanced current of the battery cell, and the rated capacity and SOH of the battery cell, which improves the accuracy and reliability of the battery cell self-discharge rate detection and can improve the stability and safety of the battery cell operation.

[0069] Figure 3 FIG. 1 is a flow chart of determining the self-discharge difference information of a battery cell in some embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention. Figure 3 As shown: Step S301, calculating a third difference between the second SOC difference and the first SOC difference.

[0070] Step S302: Determine self-discharge difference information according to the sum of the third difference and the balanced SOC.

[0071] For example, calculate the self-discharge difference information of each battery cell: R_n=-(ΔSOC_Term_n-ΔSOC_Ini_n+SOC_bal_n) (1-2); Among them, R_n is the self-discharge difference information of the nth battery cell, ΔSOC_Term_n is the second SOC difference between the SOC value of the nth battery cell and the SOC value of the reference battery cell of the battery, ΔSOC_Ini_n is the first SOC difference between the SOC value of the nth battery cell and the SOC value of the reference battery cell of the battery; SOC_bal_n is the balanced SOC of the nth battery cell relative to the reference battery cell of the battery.

[0072] By calculating the sum of the difference between the second SOC difference and the first SOC difference and the balanced SOC, the self-discharge difference information is determined, which can improve the accuracy of the detected battery cell self-discharge rate and improve the overall performance and safety of the battery.

[0073] In some embodiments, the battery has three cells, namely cell a, cell b, and cell c. After the battery controller is powered on at low voltage, it is determined whether a first detection condition is met. The first detection condition is: the SOC values ​​of cells a, b, and c are all less than 28% (SOC threshold), and cells a, b, and c are all in a stationary state.

[0074] When the first detection condition is met, the initial SOCs of battery cells a, b, and c are respectively: SOCa1=25%, SOCb1=23%, and SOCc1=20%; when determining the reference cell of the battery, determine the battery cell c with the smallest SOC value from among the battery cells a, b, and c as the reference cell of the battery.

[0075] Determine the first SOC differences between the SOC values ​​of the battery cells a, b, and c and the SOC value of the reference battery cell of the battery: ΔSOC_Ini_a=SOC5%, ΔSOC_Ini_b=3%, ΔSOC_Ini_c=0%.

[0076] Determine whether the second detection condition is met, where the second detection condition is: the SOC values ​​of battery cells a, battery cells b, and battery cells c are all less than 28%, battery cells a, battery cells b, and battery cells c are all in a stationary state, and the time period (first cumulative time) between the current moment and the moment when the first detection condition is met is greater than 30 days (time threshold).

[0077] When the second detection condition is met, the SOCs of cells a, b, and c are respectively: SOCa2=25%, SOCb2=24.5%, and SOCc2=24%. The reference cell is cell c, and the second SOC differences between the SOC values ​​of cells a, b, and c and the SOC value of cell c are determined to be: ΔSOC_Term_a=1%, ΔSOC_Term_b=0.5%, and ΔSOC_Term_c=0%; the balanced SOCs of cells a, b, and c relative to cell c are determined to be: SOC_bal_a=6%, SOC_bal_b=5%, and SOC_bal_c=0%. Based on formula (1-2), the self-discharge difference information of cells a, b, and c is determined to be: R_a=-2%=-(1%-5%+6%), R_b=-2.5%=-(0.5%-3%+5%), and R_c=0%. Compared with the negative value of the self-discharge difference information and 0, this negative value indicates that the self-discharge of the battery cell is smaller.

[0078] In some embodiments, the self-discharge rate test value of the battery cell can be determined according to the self-discharge rate test information of the battery. The self-discharge rate test information of the battery cell can be obtained by performing a self-discharge rate test on the battery cell in a laboratory. The self-discharge rate test information can be a self-discharge rate table of the battery cell, etc. The self-discharge rate test value of the battery cell can be determined by querying the self-discharge rate table of the battery cell at the current time.

[0079] For example, if the current time is December, the self-discharge rate of the battery cell corresponding to December is queried in the battery cell self-discharge rate table as the battery cell self-discharge rate test value, which may be the average self-discharge rate of all the battery cells of the battery. The battery cell self-discharge rate test value is determined based on the battery self-discharge rate test information, thereby improving the efficiency of determining the battery cell self-discharge rate test value and the accuracy of determining the battery cell self-discharge rate test value.

[0080] The self-discharge rate of the battery cell may include the maximum self-discharge rate of the battery cell, the average self-discharge rate of the battery cell, and the minimum self-discharge rate of the battery cell. Figure 4 FIG. 1 is a flow chart of determining the self-discharge rate of a battery cell in some embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention. Figure 4 As shown: Step S401 : determining maximum self-discharge difference information and minimum self-discharge difference information according to the self-discharge difference information of all the battery cells.

[0081] For example, a battery has three cells, namely cell a, cell b, and cell c. The self-discharge difference information of cell a, cell b, and cell c is: R_a=-2%, R_b=2%, and R_c=0%. Based on the self-discharge difference information of cell a, cell b, and cell c (all cells), it is determined that the maximum self-discharge difference information is R_b=2% and the minimum self-discharge difference information is R_a=-2%.

[0082] Step S402, determining the maximum self-discharge rate of the battery cell according to the maximum self-discharge difference information, the minimum self-discharge difference information and the battery cell self-discharge rate test value.

[0083] The maximum self-discharge difference information and the minimum self-discharge difference information of the battery cells are determined through the self-discharge difference information of all battery cells, and the maximum self-discharge rate of the battery cells is determined in combination with the self-discharge rate test value of the battery cells, thereby improving the accuracy and reliability of the maximum self-discharge rate detection of the battery cells, and can improve the stability and safety of the battery cell operation.

[0084] A variety of methods can be used to determine the maximum self-discharge rate of the battery cell. For example, the first difference between the maximum self-discharge difference information and the minimum self-discharge difference information is calculated; and the sum of the first difference and the battery cell self-discharge rate test value is used as the maximum self-discharge rate of the battery cell. For example: The maximum self-discharge rate of the battery cell MaxS = (MaxR-MinR) + the self-discharge rate test value of the battery cell (1-3); Wherein, MaxR is the maximum self-discharge difference information, MinR is the minimum self-discharge difference information, and (MaxR-MinR) is the first difference value.

[0085] By taking the sum of the difference between the maximum self-discharge difference information and the minimum self-discharge difference information and the self-discharge rate test value of the battery cell as the maximum self-discharge rate of the battery cell, the accuracy and reliability of the maximum self-discharge rate detection of the battery cell are improved.

[0086] Figure 5 FIG. 1 is a flow chart of determining the self-discharge rate of a battery cell in other embodiments of the method for detecting the self-discharge rate of a battery cell disclosed in the present invention. Figure 5 As shown: Step S501 : determining maximum self-discharge difference information, minimum self-discharge difference information and the number of all battery cells according to the self-discharge difference information of all battery cells.

[0087] Step S502, determining an average self-discharge rate of the battery cells according to the maximum self-discharge difference information, the minimum self-discharge difference information, the number of battery cells and the self-discharge rate test value of the battery cells.

[0088] By determining the maximum self-discharge difference information and the minimum self-discharge difference information of the battery cells and the number of battery cells based on the self-discharge difference information of all battery cells, and combining the battery cell self-discharge rate test value, the average self-discharge rate of the battery cells is determined, thereby improving the accuracy and reliability of the average self-discharge rate detection of the battery cells, and can improve the stability and safety of the battery cell operation.

[0089] The average self-discharge rate of the battery cell can be determined using a variety of methods. For example, calculating the second difference between the maximum self-discharge difference information and the minimum self-discharge difference information; calculating the quotient of the second difference and the number of battery cells; and taking the sum of the quotient and the battery cell self-discharge rate test value as the average self-discharge rate of the battery cell. For example: Average self-discharge rate of battery cell AvgS = (MaxR-MinR) / number of battery cells + test value of battery cell self-discharge rate (1-4); By calculating the quotient of the difference between the maximum self-discharge difference information and the minimum self-discharge difference information and the number of battery cells, and taking the sum of this quotient and the self-discharge rate test value of the battery cells as the average self-discharge rate of the battery cells, the maximum self-discharge rate of the battery cells can be determined, thereby improving the accuracy and reliability of the average self-discharge rate detection of the battery cells.

[0090] The cell self-discharge rate test value can be used as the cell minimum self-discharge rate. For example: The minimum self-discharge rate of the battery cell MinS = the test value of the self-discharge rate of the battery cell (1-5); By determining the minimum self-discharge rate of the battery cell according to the self-discharge rate test value of the battery cell, the accuracy of the minimum self-discharge rate of the battery cell can be improved, the stability and safety of the battery cell operation can be improved, and the performance and service life of the battery cell can be improved.

[0091] After determining the maximum self-discharge rate, minimum self-discharge rate and average self-discharge rate of the battery cell, the maximum self-discharge rate, minimum self-discharge rate and average self-discharge rate of the battery cell can be used for safety warning and fault diagnosis; if it is judged that the self-discharge rate is abnormally high, it may indicate problems such as short circuit, diaphragm damage, electrolyte decomposition, etc. inside the battery; for batteries stored for a long time, by determining the self-discharge rate of the battery cell, the remaining power can be estimated to avoid excessive discharge and damage to the battery.

[0092] In some embodiments, Figure 6 As shown, the present disclosure provides a device for detecting a self-discharge rate of a battery cell, comprising: a first information acquisition module 601 , a second information acquisition module 602 , a difference information determination module 603 and a self-discharge rate determination module 604 .

[0093] The first information acquisition module 601 determines a first SOC difference between the SOC value of the battery cell and the SOC value of a reference battery cell of the battery when the first detection condition is met; the second information acquisition module 602 determines a second SOC difference between the SOC value of the battery cell and the SOC value of the reference battery cell of the battery, as well as the balanced SOC of the battery cell relative to the reference battery cell of the battery when the second detection condition is met.

[0094] The difference information determination module 603 determines the self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC; the self-discharge rate determination module 604 determines the battery cell self-discharge rate according to the self-discharge difference information of all battery cells of the battery and the battery cell self-discharge rate test value, or according to the battery cell self-discharge rate test value.

[0095] In some embodiments, the self-discharge rate of the battery cell includes the maximum self-discharge rate of the battery cell; the self-discharge rate determination module 604 determines the maximum self-discharge difference information and the minimum self-discharge difference information based on the self-discharge difference information of all the battery cells; the self-discharge rate determination module 604 determines the maximum self-discharge rate of the battery cell based on the maximum self-discharge difference information, the minimum self-discharge difference information and the battery cell self-discharge rate test value.

[0096] For example, the self-discharge rate determination module 604 calculates a first difference between the maximum self-discharge difference information and the minimum self-discharge difference information; the self-discharge rate determination module 604 takes the sum of the first difference and the cell self-discharge rate test value as the cell maximum self-discharge rate.

[0097] The self-discharge rate of the battery cells includes the average self-discharge rate of the battery cells; the self-discharge rate determination module 604 determines the maximum self-discharge difference information, the minimum self-discharge difference information and the number of battery cells of all the battery cells according to the self-discharge difference information of all the battery cells; the self-discharge rate determination module 604 determines the average self-discharge rate of the battery cells according to the maximum self-discharge difference information, the minimum self-discharge difference information, the number of battery cells and the self-discharge rate test value of the battery cells.

[0098] For example, the self-discharge rate determination module 604 calculates the second difference between the maximum self-discharge difference information and the minimum self-discharge difference information, and calculates the quotient of the second difference and the number of battery cells; the self-discharge rate determination module 604 takes the sum of the quotient and the battery cell self-discharge rate test value as the average self-discharge rate of the battery cells.

[0099] The self-discharge rate of the battery cell includes the minimum self-discharge rate of the battery cell; the self-discharge rate determination module 604 uses the test value of the self-discharge rate of the battery cell as the minimum self-discharge rate of the battery cell.

[0100] In some embodiments, the second information acquisition module 602 determines the cumulative time difference of balancing of the battery cell relative to the reference battery cell of the battery and the balancing current of the battery cell during the time period from the moment when the first detection condition is met to the moment when the second detection condition is met; the second information acquisition module 602 acquires the rated capacity and the state of health SOH of the battery cell; the second information acquisition module 602 determines the balancing SOC based on the cumulative time difference of balancing, balancing current, rated capacity and SOH.

[0101] The difference information determination module 603 calculates a third difference between the second SOC difference and the first SOC difference, and determines the self-discharge difference information according to the sum of the third difference and the equilibrium SOC.

[0102] In some embodiments, Figure 7 As shown, the present disclosure provides a device for detecting the self-discharge rate of a battery cell, which includes, in addition to a first information acquisition module 601, a second information acquisition module 602, a difference information determination module 603 and a self-discharge rate determination module 604, a reference battery cell determination module 605 and a third information acquisition module 606.

[0103] When determining the reference cell of the battery, the reference cell determination module 605 determines the cell with the smallest SOC value from all the cells of the battery as the reference cell of the battery. The third information acquisition module 606 determines the cell self-discharge rate test value according to the self-discharge rate test information of the battery.

[0104] Figure 8 Schematic diagram of modules of some other embodiments of the detection device of the self-discharge rate of a battery cell according to the present disclosure. Figure 8As shown, the battery cell self-discharge rate detection device may include a memory 801, a processor 802, a communication interface 803, and a bus 804. The memory 801 is used to store instructions, the processor 802 is coupled to the memory 801, and the processor 802 is configured to execute the above-mentioned battery cell self-discharge rate detection method based on the instructions stored in the memory 801.

[0105] The memory 801 may be a high-speed RAM memory, a non-volatile memory, etc. The memory 801 may also be a memory array. The memory 801 may also be divided into blocks, and the blocks may be combined into virtual volumes according to certain rules. The processor 802 may be a central processing unit CPU, or an application specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the method for detecting the self-discharge rate of a battery cell disclosed in the present invention.

[0106] In some embodiments, the present disclosure provides a computer-readable storage medium storing computer instructions, and the instructions are executed by a processor to implement the method for detecting the self-discharge rate of a battery cell in any of the above embodiments.

[0107] Computer readable storage media can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive enumeration) of readable storage media can include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0108] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] Embodiments of the present disclosure may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to execute the steps of the method for detecting the self-discharge rate of a battery cell according to various embodiments of the present disclosure described in the above “Exemplary Method” section of this specification.

[0110] The steps of the method of the present disclosure are not limited to the order specifically described above, unless otherwise specifically stated. In addition, in some embodiments, the present disclosure may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present disclosure. Thus, the present disclosure also covers a recording medium storing a program for executing the method according to the present disclosure.

[0111] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for detecting the self-discharge rate of a battery cell, characterized in that: include: When a first detection condition is met, determining a first SOC difference between an SOC value of a cell of the battery and an SOC value of a reference cell of the battery; When a second detection condition is met, determining a second SOC difference between the SOC value of the battery cell and the SOC value of a reference battery cell of the battery, and a balanced SOC of the battery cell relative to the reference battery cell of the battery; Determining self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC; The cell self-discharge rate is determined according to the cell self-discharge rate test value, the self-discharge difference information of all the cells of the battery, or according to the cell self-discharge rate test value.

2. The detection method according to claim 1, characterized in that The self-discharge rate of the battery cell includes: the maximum self-discharge rate of the battery cell; according to the self-discharge rate test value of the battery cell and the self-discharge difference information of all the battery cells of the battery, determining the self-discharge rate of the battery cell includes: Determining maximum self-discharge difference information and minimum self-discharge difference information according to the self-discharge difference information of all the battery cells; The maximum self-discharge rate of the battery cell is determined according to the maximum self-discharge difference information, the minimum self-discharge difference information and the battery cell self-discharge rate test value.

3. The detection method according to claim 2, characterized in that The determining the maximum self-discharge rate of the battery cell according to the maximum self-discharge difference information, the minimum self-discharge difference information and the battery cell self-discharge rate test value comprises: Calculating a first difference between the maximum self-discharge difference information and the minimum self-discharge difference information; The sum of the first difference and the battery cell self-discharge rate test value is used as the maximum self-discharge rate of the battery cell.

4. The detection method according to claim 1, characterized in that The self-discharge rate of the battery cell includes: an average self-discharge rate of the battery cell; determining the self-discharge rate of the battery cell according to the self-discharge rate test value of the battery cell and the self-discharge difference information of all the battery cells of the battery includes: Determine the maximum self-discharge difference information, the minimum self-discharge difference information and the number of cells of all the cells according to the self-discharge difference information of all the cells; The average self-discharge rate of the battery cells is determined according to the maximum self-discharge difference information, the minimum self-discharge difference information, the number of battery cells and the self-discharge rate test value of the battery cells.

5. The detection method according to claim 2, characterized in that: The determining the average self-discharge rate of the battery cells according to the maximum self-discharge difference information, the minimum self-discharge difference information, the number of battery cells and the self-discharge rate test value of the battery cells comprises: Calculating a second difference between the maximum self-discharge difference information and the minimum self-discharge difference information; Calculating a quotient of the second difference and the number of battery cells; The sum of the quotient and the test value of the self-discharge rate of the battery cell is taken as the average self-discharge rate of the battery cell.

6. The detection method according to claim 1, characterized in that The self-discharge rate of the battery cell includes: the minimum self-discharge rate of the battery cell; and according to the self-discharge rate test value of the battery cell, determining the self-discharge rate of the battery cell includes: The self-discharge rate test value of the battery cell is used as the minimum self-discharge rate of the battery cell.

7. The detection method according to claim 1, characterized in that Determining the balanced SOC of the cell relative to a reference cell of the battery includes: Determine a cumulative balancing time difference of the battery cell relative to a reference battery cell of the battery and a balancing current of the battery cell during a time period from when the first detection condition is satisfied to when the second detection condition is satisfied; Obtain the rated capacity and health status SOH of the battery cell; The balanced SOC is determined according to the balanced accumulated time difference, the balanced current, the rated capacity and the SOH.

8. The detection method according to claim 1, characterized in that The determining the self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC includes: calculating a third difference between the second SOC difference and the first SOC difference; The self-discharge difference information is determined according to the sum of the third difference and the balanced SOC.

9. The detection method according to claim 1, characterized in that: include: When determining the reference cell of the battery, a cell with the smallest SOC value is determined from all the cells of the battery as the reference cell of the battery.

10. The detection method according to claim 1, characterized in that: include: Determine the self-discharge rate test value of the battery cell according to the self-discharge rate test information of the battery.

11. The detection method according to any one of claims 1 to 10, characterized in that: The first detection condition includes: the SOC values ​​of all the cells of the battery are less than the SOC threshold, and all the cells are in a stationary state.

12. The detection method according to any one of claims 1 to 10, characterized in that: The second detection condition includes: the SOC values ​​of all the cells of the battery are less than the SOC threshold, all the cells are in a stationary state, and the calculated accumulated time of the self-discharge rate is greater than the time threshold; Among them, the self-discharge rate calculation cumulative time includes: a first cumulative time or a second cumulative time; the first cumulative time includes: a time period between the current moment and the moment when the first detection condition is met; the second cumulative time includes: a time period between the last time the battery was synchronized and the production date of the battery.

13. A device for detecting the self-discharge rate of a battery cell, characterized in that: include: A first information acquisition module, configured to determine a first SOC difference between an SOC value of a battery cell of a battery and an SOC value of a reference battery cell of the battery when a first detection condition is met; a second information acquisition module, configured to determine, when a second detection condition is met, a second SOC difference between the SOC value of the battery cell and the SOC value of a reference battery cell of the battery, and a balanced SOC of the battery cell relative to the reference battery cell of the battery; A difference information determination module, configured to determine the self-discharge difference information of the battery cell based on the first SOC difference, the second SOC difference and the balanced SOC; The self-discharge rate determination module is used to determine the self-discharge rate of the battery cell according to the self-discharge rate test value of the battery cell, the self-discharge difference information of all the battery cells of the battery, or according to the self-discharge rate test value of the battery cell.

14. A device for detecting the self-discharge rate of a battery cell, characterized in that: include: Memory; and a processor coupled to the memory, the processor being configured to execute the method according to any one of claims 1 to 12 based on instructions stored in the memory.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are executed by a processor to perform the method according to any one of claims 1 to 12.

16. A computer program product, characterized in that The computer program product stores computer instructions, and the computer instructions are executed by a processor to perform the method according to any one of claims 1 to 12.

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