Methods, apparatus, computer equipment and media for determining the K-value of battery cells

Abstract

This application discloses a method, apparatus, computer device, and storage medium for determining the K-value of a battery cell. The method includes: acquiring the cell voltage of a target battery cell at different storage times; determining a target nonlinear relationship between time and voltage based on the cell voltage at the different storage times; and determining the K-value of the target battery cell according to the target nonlinear relationship. This patent obtains the actual voltage of the battery cell at different storage times, and uses these actual voltages to determine the nonlinear relationship between time and voltage, accurately calculating the K-value of the battery cell, avoiding the deviation problem caused by only measuring the voltage at the beginning and end of the storage time to calculate the K-value.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a method, apparatus, computer equipment, and medium for determining the K-value of a battery cell. Background Technology

[0002] As the core power supply structure of computer equipment, the performance and stability of lithium batteries directly affect the user experience. In the actual production and processing of lithium batteries, the main performance parameters to be considered include the voltage change per unit time of each cell (i.e., the K value). By testing the K value of the cell, the self-discharge rate of the cell can be measured.

[0003] In related technologies, the cell is left to stand for a period of time, and the cell voltage is collected. Then, the quotient of the voltage drop during this period and the number of days of standing is used as the K value.

[0004] However, in practical applications, the cell voltage does not change linearly with time, which leads to inaccurate calculated K values ​​and a large error between the calculated K value and the actual K value. Summary of the Invention

[0005] In view of the above problems, this application proposes a method, apparatus, computer equipment and storage medium for determining the K value of a battery cell, so as to solve the problem of deviation caused by the traditional method of directly calculating the K value using the initial and final states between voltage and time.

[0006] The first aspect of this application proposes a method for determining the K value of a battery cell. The method includes: obtaining the battery cell voltage at different storage times of a target battery cell, determining a target nonlinear relationship between time and voltage based on the battery cell voltage at different storage times, and determining the K value of the target battery cell according to the target nonlinear relationship.

[0007] In the technical solution of this application embodiment, compared with the traditional solution that only obtains the voltage of the battery cell at the beginning and end of the resting period to calculate the K value, this patent obtains the actual voltage of the battery cell at different storage times. By using the actual voltage of these storage times, the nonlinear relationship between time and voltage can be determined, and the K value of the battery cell can be accurately calculated, avoiding the deviation problem caused by only measuring the voltage at the beginning and end of the state to calculate the K value.

[0008] In some embodiments, obtaining the cell voltage of the target cell at different storage times includes: collecting the cell voltage of the target cell every preset period during the storage period of the target cell; and storing the mapping relationship between the cell voltage collected each time and the storage time. Since the cells are usually stored in a designated location in a warehouse after production, and the storage period is a static management phase, the convenient conditions during the storage period can be used to periodically collect and record the mapping relationship between the cell voltage and time, which is convenient for subsequent reading and calculation of the K value.

[0009] In some embodiments, the step of collecting the cell voltage of the target battery cell at preset intervals includes: controlling the contacts of the collection device to connect with the target battery cell at preset intervals to collect the cell voltage of the target battery cell. By configuring dedicated collection devices in the warehouse and controlling the contacts of the collection devices to connect with each battery cell sequentially, the voltage of each battery cell can be automatically collected, avoiding measurement errors and the investment of manpower and resources caused by manual measurement.

[0010] In some embodiments, determining the target nonlinear relationship between time and voltage based on the cell voltage at different storage times includes: using the cell voltage at different storage times to fit a nonlinear relationship between time and voltage as the target nonlinear relationship. Since the relationship between cell voltage and time is not a simple linear relationship in practical applications, it is necessary to use multiple sets of correspondences between storage time and cell voltage to obtain the nonlinear relationship between time and voltage through fitting.

[0011] In some embodiments, determining the target nonlinear relationship between time and voltage based on the cell voltage at different storage times includes: fitting a nonlinear relationship between time and voltage using the cell voltage at different storage times; collecting the actual cell voltage of the target cell at the current storage time when the target cell is put into service; and determining the target nonlinear relationship based on the actual cell voltage at the current storage time and the nonlinear relationship. Since cells are typically stored at the assembly site for a period of time before being assembled into modules during the process of leaving the warehouse, the nonlinear relationship fitted by cell voltages collected at different storage times during storage may not match the state of the cells when assembling the modules, or the nonlinear relationship fitted by data collected during storage may not be accurate. Therefore, it is necessary to further determine the target nonlinear relationship based on the actual cell voltage at the current time and the nonlinear relationship fitted during storage to improve the accuracy of the target nonlinear relationship.

[0012] In some embodiments, acquiring the actual cell voltage of the target cell at the current storage time includes: acquiring the actual cell voltage of the target cell at the current storage time using a capacity testing device during a capacity test. Cells typically require capacity testing at the assembly site; therefore, acquiring the actual cell voltage at the current time during the capacity test allows for a one-time K-value calculation, which is both quick and efficient.

[0013] In some embodiments, determining the target nonlinear relationship based on the actual cell voltage at the current storage time and the nonlinear relationship includes: determining whether the nonlinear relationship meets a preset accuracy condition based on the current storage time and the actual cell voltage; if it does, then determining the nonlinear relationship as the target nonlinear relationship; if it does not, then fitting a new nonlinear relationship between time and voltage using the cell voltage at different storage times and the actual cell voltage at the current storage time as the target nonlinear relationship. By pre-setting the accuracy condition, the accuracy of the fitted nonlinear relationship during storage can be determined based on the current storage time and the actual cell voltage during on-site assembly.

[0014] In some embodiments, determining whether the nonlinear relationship meets a preset accuracy condition based on the current storage time and the actual cell voltage includes: determining the theoretical cell voltage at the current storage time based on the nonlinear relationship, and obtaining the voltage difference between the theoretical cell voltage and the actual cell voltage; determining the standard voltage difference corresponding to the current storage time; determining that the nonlinear relationship does not meet the preset accuracy condition if the difference between the voltage difference and the standard voltage difference exceeds a threshold; and determining that the nonlinear relationship meets the preset accuracy condition if the difference between the voltage difference and the standard voltage difference does not exceed the threshold. Since the standard voltage difference represents the standard difference between the actual voltage and the theoretical voltage of the target cell at the current storage time, by calculating the voltage difference between the theoretical cell voltage and the actual cell voltage and comparing it with the standard voltage difference, it is possible to accurately determine whether the nonlinear relationship during storage meets the accuracy requirements.

[0015] In some embodiments, determining the standard voltage difference corresponding to the current storage time includes: determining the cell type of the target cell; obtaining a standard difference function corresponding to the cell type; and substituting the current storage time into the standard difference function to obtain the standard voltage difference. Since different cell types have different electrical properties, a more accurate standard voltage difference can be obtained by pre-determining a corresponding standard difference function for each cell type.

[0016] In some embodiments, determining the K value of the target battery cell based on the target nonlinear relationship includes: differentiating the target nonlinear relationship to obtain a derivative function; substituting different storage times into the derivative function to obtain derivative values ​​corresponding to different storage times; and determining the average of the derivative values ​​as the K value of the target battery cell. By differentiating the target nonlinear relationship to obtain derivative values ​​for different storage times, these derivative values ​​can represent the tangent slope at the corresponding storage time, i.e., the K value. Therefore, the average of all obtained derivative values ​​can be used as the accurate K value of the battery cell.

[0017] A second aspect of this application discloses a battery cell K-value determination device, the device comprising:

[0018] The data acquisition module is used to acquire the cell voltage of the target cell at different storage times;

[0019] The data processing module is used to determine the target nonlinear relationship between time and voltage based on the cell voltage under different storage times;

[0020] The voltage drop determination module is used to determine the K value of the target cell based on the target nonlinear relationship.

[0021] A third aspect of this application provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method described in the first aspect above.

[0022] The fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect above.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0025] Figure 1 A schematic diagram illustrating the calculation of the K value based on the initial and final states of the battery cell during the static storage process using existing technologies.

[0026] Figure 2This is a schematic diagram of the actual voltage drop curve of the battery cell collected in the experiment of this application;

[0027] Figure 3 This is a flowchart illustrating an embodiment of a method for determining the K-value of a battery cell according to an exemplary embodiment of this application;

[0028] Figure 4 For the purposes of this application Figure 3 The illustrated embodiment presents a schematic diagram of a target nonlinear relationship curve;

[0029] Figure 5 This application illustrates a flowchart of a specific implementation of determining the K-value of a battery cell according to an exemplary embodiment.

[0030] Figure 6 This is a schematic diagram of a battery cell K-value determination device according to an exemplary embodiment of this application;

[0031] Figure 7 This is a schematic diagram of the hardware structure of a computer device according to an exemplary embodiment of this application;

[0032] Figure 8 This is a schematic diagram illustrating the structure of a storage medium according to an exemplary embodiment of this application. Detailed Implementation

[0033] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0038] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0039] A lithium battery is composed of multiple cells. The quality of a lithium battery is usually determined by its operating parameters. In the industry, the self-discharge rate of each cell is usually measured by the voltage drop (K value) of each cell per unit time.

[0040] The existing method involves storing the battery cell for a period of time, collecting the cell voltage, and using the quotient of the voltage drop during this period and the number of storage days as the K value. For example... Figure 1 As shown, the initial time and cell voltage when the cell is left to stand are denoted as (t1, U1), and the end time and cell voltage when the cell is left to stand are denoted as (t2, U2). Then, the K value is calculated: K = (U1 - U2) / (t2 - t1).

[0041] However, the inventors noticed that the actual voltage change of the battery cell is not linearly related to time, such as... Figure 2 As shown, the voltage drop curve between the cell voltage and time obtained by the inventor's experimental test is shown (shown by the dashed line). However, if the K value between the initial and final states is directly calculated according to the existing method: K = (U1-U3) / (t3-t1), there is a large error with the actual K value represented by the curve. Furthermore, the longer the static storage time, the greater the deviation between the K value calculated according to the existing method and the actual K value. Therefore, with the increase of static storage time, the irrationality of the existing calculation method becomes more and more obvious.

[0042] To address the issue of deviations in calculating the K-value using the initial and final states of voltage and time in traditional methods, the applicant discovered that by acquiring the cell voltage at different storage times and determining the target nonlinear relationship between time and voltage based on these voltages, the K-value of the cell can be accurately calculated, avoiding the deviations caused by calculating the K-value by only measuring the voltage at the initial and final states.

[0043] The method for determining the K-value of a battery cell disclosed in this application can be used, but is not limited to, in the production process of secondary batteries, and can also be used in the production process of other similar structures.

[0044] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0045] Figure 3 This is a flowchart illustrating an embodiment of a method for determining the K-value of a battery cell according to an exemplary embodiment of this application. The method for determining the K-value of a battery cell includes the following steps:

[0046] Step 101: Obtain the cell voltage of the target cell at different storage times.

[0047] Among them, the target cell refers to the cell whose K value needs to be calculated, the storage time refers to how long the target cell has been stored, and the cell voltage refers to the voltage value of the target cell at each storage time.

[0048] For example, if the cell voltage of the target cell is recorded every day, and it is stored for 15 days, then 15 sets of data on cell voltage and storage time can be obtained.

[0049] In an optional embodiment, since the battery cells are usually stored in a designated location in a warehouse after production, and the battery cells are in a static management phase during storage, the convenient conditions during storage can be utilized to collect the battery cell voltage of the target battery cell once every preset period during the storage period of the target battery cell, and store the mapping relationship between the battery cell voltage collected each time and the storage time, so as to use it for subsequent reading and calculation of the K value.

[0050] The preset cycle can be set according to actual needs. For example, the cell voltage can be collected once every 24 hours, that is, once a day, so a series of cell voltage and storage time data can be generated (0, U0), (1, U1), (2, U2), (3, U3)...

[0051] In practical implementation, since cell voltage needs to be collected periodically, manual measurement and collection each time would result in a large investment of manpower and resources. Therefore, this application configures a special collection device in the warehouse and controls the contacts of the collection device to connect with each cell in sequence, thereby automatically collecting the voltage of each cell and avoiding measurement errors and manpower and resources investment caused by manual measurement.

[0052] Based on this, for the process of collecting the cell voltage of the target cell every preset period, the contacts of the acquisition device are controlled to connect with the target cell every preset period to achieve automatic collection of the cell voltage of the target cell and avoid manual input.

[0053] Furthermore, since the warehouse stores a large number of battery cells, each cell is equipped with an identification code to distinguish its unique identifier. Therefore, while collecting the voltage of a target battery cell, the acquisition device can also scan the target cell's identification code to obtain its identification information. The mapping relationship between the cell identification information and its storage time and voltage is then stored, facilitating subsequent retrieval of all storage times and voltage mappings for the target battery cell based on its identification information.

[0054] Based on the above description, the data acquisition equipment configured in the warehouse not only has the function of acquiring battery cell voltage, but also has the function of scanning and identifying codes.

[0055] Step 102: Determine the target nonlinear relationship between time and voltage based on the cell voltage under different storage times.

[0056] The target nonlinear relationship reflects the relationship between cell storage time and voltage. Generally, storage time and voltage are inversely correlated; the longer the storage time, the lower the cell voltage. The relationship between the two is not linear but nonlinear. Specifically, the target nonlinear relationship can be represented by a high-power function.

[0057] In one alternative embodiment, the nonlinear relationship between time and voltage is directly fitted using the cell voltage at different storage times as the target nonlinear relationship. Since the relationship between cell voltage and time is not a simple linear one in practical applications, multiple sets of correspondences between storage time and cell voltage are needed to obtain the nonlinear relationship between time and voltage through fitting.

[0058] It is understandable that a correlation fitting algorithm can be used to fit the nonlinear relationship between multiple storage times and cell voltages. This application does not specifically limit the specific fitting algorithm.

[0059] In another alternative embodiment, since the cells are usually stored at the assembly site for a period of time before being assembled into the module during the process of leaving the warehouse, the nonlinear relationship fitted by the cell voltage at different storage times collected during the storage period may not match the state of the cells when assembling the module, or the nonlinear relationship fitted by the data collected during the storage period may not be very accurate.

[0060] Therefore, by using the cell voltage at different storage times to fit the nonlinear relationship between time and voltage, instead of directly using it as the target nonlinear relationship, when the target cell is put into service, the actual cell voltage of the target cell at the current storage time is collected, and the target nonlinear relationship is determined based on the actual cell voltage at the current storage time and the nonlinear relationship, so as to improve the accuracy of the nonlinear relationship between time and voltage.

[0061] Among them, the cell online process is the process of transporting the cells from the warehouse to the field for module assembly. At the field, the actual cell voltage of the target cell under the current storage time can be collected using equipment with the same precision as the collection equipment in the warehouse, so as to ensure the consistency of voltage collection.

[0062] In one possible implementation, the battery cell typically needs to undergo a capacity test at the assembly site. Based on this, this embodiment uses a capacity testing device to collect the actual battery cell voltage of the target battery cell at the current storage time, so as to complete the K-value calculation at the same time as the capacity test, which is both fast and efficient.

[0063] Regarding the specific process of determining the target nonlinear relationship, optionally, based on the current storage time and the actual cell voltage, it is determined whether the nonlinear relationship meets the preset accuracy conditions. If it does, the nonlinear relationship is determined as the target nonlinear relationship; if it does not, a new nonlinear relationship between time and voltage is fitted using the cell voltage at different storage times and the actual cell voltage at the current storage time as the target nonlinear relationship. In this way, by pre-setting the accuracy conditions, the accuracy of the fitted nonlinear relationship during storage can be determined based on the current storage time and the actual cell voltage during on-site assembly.

[0064] In cases where the nonlinear relationship fitted during storage does not meet the accuracy requirements, a new nonlinear relationship is fitted by combining the newly collected storage time and cell voltage data with the data collected during storage. Since new data is involved in the fitting, the accuracy of the fitted new nonlinear relationship will be higher.

[0065] Furthermore, regarding the process of determining whether the nonlinear relationship meets the preset accuracy conditions based on the current storage time and the actual cell voltage, the theoretical cell voltage at the current storage time is determined through the nonlinear relationship. Then, the voltage difference between the theoretical cell voltage and the actual cell voltage is obtained, and the standard voltage difference corresponding to the current storage time is determined. If the difference between the voltage difference and the standard voltage difference exceeds a threshold, it is determined that the nonlinear relationship does not meet the preset accuracy conditions. If the difference between the voltage difference and the standard voltage difference does not exceed the threshold, it is determined that the nonlinear relationship meets the preset accuracy conditions.

[0066] Among them, the theoretical cell voltage is a theoretical value obtained by substituting the current storage time into the nonlinear relationship obtained during the storage period. The standard voltage difference represents the standard difference between the actual voltage and the theoretical voltage of the target cell at the current storage time. Therefore, by calculating the voltage difference between the theoretical cell voltage and the actual cell voltage and comparing it with the standard voltage difference, it is possible to accurately determine whether the nonlinear relationship during the storage period meets the accuracy requirements.

[0067] In one optional specific embodiment, for the process of determining the standard voltage difference, after determining the cell type of the target cell, the standard difference function corresponding to the cell type is obtained, and the current storage time is substituted into the standard difference function to obtain the standard voltage difference.

[0068] Since different cell types have different electrical properties, a more accurate standard voltage difference is obtained by pre-determining a corresponding standard difference function for each cell type.

[0069] Optionally, the cell type of the target battery cell can be obtained by scanning the identification code of the target battery cell.

[0070] For example, the cell types may include lithium iron phosphate-graphite, lithium manganese oxide-graphite, lithium nickel cobalt manganese oxide-graphite, lithium nickel cobalt aluminum oxide-graphite, and other types, and each cell type has a pre-defined standard difference function.

[0071] Step 103: Determine the K value of the target cell based on the target nonlinear relationship.

[0072] The K value of the target cell indicates its self-discharge rate throughout the measurement period.

[0073] In an optional embodiment, the derivative function is obtained by differentiating the target nonlinear relationship, and then different storage times are substituted into the derivative function to obtain the derivative values ​​corresponding to different storage times. The average of these derivative values ​​is then used as the K value of the target cell.

[0074] Among them, by taking the derivative of the target nonlinear relationship, the derivative values ​​obtained for different storage times can represent the tangent slope at the corresponding storage time, that is, the K value. Thus, the average of all the obtained derivative values ​​can be used as the accurate K value of the battery cell.

[0075] See Figure 4 As shown, the target nonlinear relationship curve is obtained from (t1, U1), (t2, U2), (t3, U3)...(tm, Um). Figure 4 As can be seen, the curve is a high power relationship curve. By taking the derivative of the curve with respect to time t, we can calculate the derivative values ​​at t = t1, t2, t3...tm. These derivative values ​​are the slopes of the tangent at each time point, which can be approximated as multiple K values. By calculating the average of these derivative values, we can accurately output the K value: K≈(K1+K2+K3+...+Km) / m.

[0076] Depend on Figure 4 As can be seen, all derivative values ​​are negative. Therefore, after obtaining the mean of the derivative values, the absolute value can be taken as the K value.

[0077] For example, after differentiating the target nonlinear relationship curve function U(t) with respect to time t, the derivative function is obtained as U'(t) = -83.08 + 0.4154t + 0.005489 * 3t^2. The derivative values ​​U'(t) are calculated for t = 0, 1, 2, ..., and then the average of these derivative values ​​U'(t) is taken, and the absolute value is used to output the accurate K value.

[0078] Those skilled in the art will understand that when calculating the K value, it can be the average of the derivative values ​​of all storage times of the target cell, or it can be the average of the derivative values ​​of storage times longer than the target cell.

[0079] This completes the above. Figure 1 The process for determining the K-value of a battery cell shown in this patent differs from traditional methods, which only obtain the voltage at the beginning and end of the cell's resting period to calculate the K-value. This patent obtains the actual voltage of the cell at different storage times and uses these actual voltages to determine the nonlinear relationship between time and voltage, thus accurately calculating the K-value of the cell and avoiding the deviation problem caused by only measuring the voltage at the beginning and end of the storage period to calculate the K-value.

[0080] Regarding the technical solutions provided in the above embodiments, the following is a comprehensive description of the present application solution using a specific embodiment.

[0081] Figure 5 The flowchart illustrating a specific implementation of determining the K-value of a battery cell according to an exemplary embodiment of this application includes the following steps:

[0082] Step 1: Data collection process during battery storage.

[0083] During the warehousing period, the completed battery cells are stored at the designated positions in the warehouse. When the acquisition equipment manages the storage, it will scan the data of the battery cells in the storage location every day, automatically measure the voltage of the battery cells, and upload the battery cell identification information, battery cell voltage, and storage time to the server database.

[0084] Optionally, the acquisition equipment uses a camera to scan the identification code of the battery cell to obtain the battery cell identification information, and at the same time, it will also connect its own contacts to the battery cell to measure the battery cell voltage.

[0085] Step 2: The process of fitting the non-linear relationship function between voltage and time.

[0086] Among them, by reading the data of daily voltage and storage time from the server database, the non-linear relationship function U(t) is automatically fitted.

[0087] Step 3: The process of in-line inspection of battery cells.

[0088] Among them, during the process of assembling the module, the current storage time tm is automatically retrieved by scanning, and tm is substituted into U(t) to calculate the theoretical battery cell voltage U(tm).

[0089] Step 4: The process of assigning the voltage difference X.

[0090] The actual battery cell voltage Um is acquired, and U(tm) - Um is calculated, and the result is assigned to X.

[0091] Optionally, the actual battery cell voltage Um is acquired in a contact manner in the capacity machine equipment, so as to complete a one-time inspection while conducting the capacity experiment.

[0092] Step 5: The process of judging whether the inequality X - X(tm) < A holds.

[0093] The battery cell type of the battery cell is obtained by scanning the code, and the standard difference function X(t) corresponding to this battery cell type is selected, and the standard voltage difference X(tm) at the current storage time tm is calculated, and it is judged whether the inequality X - X(tm) < A holds.

[0094] Step 6: If the inequality holds, output the non-linear relationship function U(t) fitted during the warehousing period.

[0095] Step 7: If the inequality does not hold, add the point (tm, Um) collected during the in-line inspection to the non-linear relationship function U(t), and refit to obtain the function Ua(t).

[0096] Step 8: Replace U(t) with the function Ua(t).

[0097] Step 9: Take the derivative of the function U(t) and calculate the mean value of the derivative values ​​for t = t1, t2...tm, and output the value of K.

[0098] This completes the above. Figure 5 The specific process for determining the K value of the battery cell is shown below.

[0099] Corresponding to the embodiments of the aforementioned cell K-value determination method, this application also provides embodiments of a cell K-value determination device.

[0100] Figure 6 This is a schematic diagram illustrating the structure of a cell K-value determination device according to an exemplary embodiment of this application. This device is used to execute the cell K-value determination method provided in any of the above embodiments, such as... Figure 6 As shown, the cell K-value determination device includes:

[0101] Data acquisition module 610 is used to acquire the cell voltage of the target cell under different storage times;

[0102] Data processing module 620 is used to determine the target nonlinear relationship between time and voltage based on the cell voltage under different storage times;

[0103] The voltage drop determination module 630 is used to determine the K value of the target cell based on the target nonlinear relationship.

[0104] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0105] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0106] This application also provides a computer device corresponding to the cell K-value determination method provided in the foregoing embodiments, for executing the cell K-value determination method described above.

[0107] Figure 7This application illustrates a hardware structure diagram of a computer device according to an exemplary embodiment. The computer device includes a communication interface 601, a processor 602, a memory 603, and a bus 604. The communication interface 601, processor 602, and memory 603 communicate with each other via the bus 604. The processor 602 can execute the cell K-value determination method described above by reading and executing machine-executable instructions corresponding to the control logic of the cell K-value determination method in the memory 603. The specific content of this method is described in the above embodiment and will not be repeated here.

[0108] The memory 603 mentioned in this application can be any electronic, magnetic, optical, or other physical storage device, and can contain stored information such as executable instructions, data, etc. Specifically, the memory 603 can be RAM (Random Access Memory), flash memory, storage drive (such as hard disk drive), any type of storage disk (such as optical disc, DVD, etc.), or similar storage media, or combinations thereof. Communication between this system network element and at least one other network element is achieved through at least one communication interface 601 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc., can be used.

[0109] Bus 604 can be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory 603 is used to store programs, and the processor 602 executes the programs after receiving execution instructions.

[0110] Processor 602 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 602 or by instructions in software form. The processor 602 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), an On-Premises Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor.

[0111] The computer device provided in this application embodiment and the cell K-value determination method provided in this application embodiment are based on the same inventive concept and have the same beneficial effects as the methods they adopt, operate or implement.

[0112] This application also provides a computer-readable storage medium corresponding to the cell K-value determination method provided in the foregoing embodiments. Please refer to... Figure 8 As shown, the computer-readable storage medium is an optical disc 30, on which a computer program (i.e., a program product) is stored. When the computer program is run by a processor, it executes the cell K-value determination method provided in any of the aforementioned embodiments.

[0113] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other optical and magnetic storage media, which will not be elaborated here.

[0114] The computer-readable storage medium provided in the above embodiments of this application and the cell K-value determination method provided in the embodiments of this application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by the application programs stored therein.

[0115] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0116] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0117] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for determining the K-value of a battery cell, characterized in that, The method includes: Obtain the cell voltage of the target cell at different storage times; The target nonlinear relationship between time and voltage is determined based on the cell voltage under different storage times. The K value of the target battery cell is determined based on the target nonlinear relationship; The determination of the target nonlinear relationship between time and voltage based on the cell voltage under different storage times includes: Using the cell voltages at different storage times, a nonlinear relationship between time and voltage is fitted; when the target cell is put into operation, the actual cell voltage of the target cell at the current storage time is collected; based on the actual cell voltage at the current storage time and the nonlinear relationship, the target nonlinear relationship is determined. The step of determining the target nonlinear relationship based on the actual cell voltage at the current storage time and the nonlinear relationship includes: Based on the current storage time and the actual cell voltage, determine whether the nonlinear relationship meets the preset accuracy conditions; if it does, then the nonlinear relationship is determined as the target nonlinear relationship; if it does not, then use the cell voltage at different storage times and the actual cell voltage at the current storage time to fit a new nonlinear relationship between time and voltage as the target nonlinear relationship.

2. The method according to claim 1, characterized in that, The process of obtaining the cell voltage of the target cell at different storage times includes: During the storage of the target battery cell, the cell voltage of the target battery cell is collected once every preset period; Store the mapping relationship between the cell voltage collected each time and the storage time.

3. The method according to claim 2, characterized in that, The step of collecting the cell voltage of the target battery cell at preset intervals includes: The contacts of the data acquisition device are controlled to connect with the target battery cell at preset intervals to acquire the battery cell voltage.

4. The method according to claim 1, characterized in that, The step of collecting the actual cell voltage of the target cell at the current storage time includes: During the capacity test, the actual cell voltage of the target cell at the current storage time is collected by a capacity testing device.

5. The method according to claim 1, characterized in that, The step of determining whether the nonlinear relationship meets the preset accuracy condition based on the current storage time and the actual cell voltage includes: The theoretical cell voltage at the current storage time is determined based on the nonlinear relationship, and the voltage difference between the theoretical cell voltage and the actual cell voltage is obtained. Determine the standard voltage difference corresponding to the current storage time; If the difference between the voltage difference and the standard voltage difference exceeds a threshold, it is determined that the nonlinear relationship does not meet the preset accuracy condition. Based on the fact that the difference between the voltage difference and the standard voltage difference does not exceed a threshold, it is determined that the nonlinear relationship meets the preset accuracy condition.

6. The method according to claim 5, characterized in that, Determining the standard voltage difference corresponding to the current storage time includes: Determine the cell type of the target battery cell; Obtain the standard difference function corresponding to the cell type; Substituting the current storage time into the standard difference function yields the standard voltage difference.

7. The method according to any one of claims 1-6, characterized in that, Determining the K value of the target battery cell based on the target nonlinear relationship includes: Differentiating the target nonlinear relationship yields the derivative function; Substitute different storage times into the derivative function to obtain the derivative values ​​corresponding to different storage times; The mean value of the derivative is determined as the K value of the target battery cell.

8. A device for determining the K-value of a battery cell, characterized in that, The device includes: The data acquisition module is used to acquire the cell voltage of the target cell at different storage times; The data processing module is used to determine the target nonlinear relationship between time and voltage based on the cell voltage under different storage times; A voltage drop determination module is used to determine the K value of the target cell based on the target nonlinear relationship; The data processing module is specifically used to fit the nonlinear relationship between time and voltage using the cell voltage at different storage times; when the target cell is put into operation, it collects the actual cell voltage of the target cell at the current storage time; and determines the target nonlinear relationship based on the actual cell voltage at the current storage time and the nonlinear relationship. The data processing module is specifically used to determine whether the nonlinear relationship meets a preset accuracy condition based on the actual cell voltage at the current storage time and the nonlinear relationship during the process of determining the target nonlinear relationship. If it does, the nonlinear relationship is determined as the target nonlinear relationship. If it does not, a new nonlinear relationship between time and voltage is fitted using the cell voltage at different storage times and the actual cell voltage at the current storage time as the target nonlinear relationship.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the steps of the method as described in any one of claims 1-7.

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