Diffusion coefficient determination method and device, computer equipment and storage medium

Abstract

The invention relates to a diffusion coefficient determination method and device, computer equipment and a storage medium. The method comprises the following steps: applying a test current to a pre-prepared symmetric battery, and obtaining relaxation voltages at a plurality of acquisition moments after the application of the test current is stopped; wherein the symmetrical battery is a battery with a positive electrode and a negative electrode made of the same electrode material, the symmetrical battery comprises an electrolyte and two preset electrodes, and the solid phase diffusion coefficient of the preset electrodes is greater than a preset coefficient value; and determining the liquid phase diffusion coefficient of the electrolyte according to the relaxation voltages at the plurality of acquisition moments. By adopting the method, the liquid phase diffusion coefficient of the electrolyte can be directly determined, the test error can be reduced, and the test stability and the test result consistency can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a method, apparatus, computer device, and storage medium for determining diffusion coefficient. Background Technology

[0002] With the development of new energy technologies, battery manufacturing processes have also advanced rapidly. Parameters of the electrolyte in a battery include conductivity, viscosity, diffusion coefficient, and transport number. These parameters affect battery performance, with the diffusion coefficient having a particularly significant impact on high-rate charge and discharge. A high diffusion coefficient means the battery can cycle more efficiently, reducing safety hazards such as localized overheating and short circuits caused by ion accumulation, thereby improving battery safety.

[0003] Therefore, accurately assessing the diffusion coefficient has become one of the main problems in electrolyte development. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a method, apparatus, computer device, and storage medium for determining the diffusion coefficient, which can directly determine the liquid phase diffusion coefficient of the electrolyte, and can also reduce test errors, improve test stability, and enhance the consistency of test results.

[0005] In a first aspect, this application provides a method for determining the diffusion coefficient, the method comprising: applying a test current to a pre-prepared symmetrical cell, and acquiring relaxation voltages at multiple acquisition times after stopping the application of the test current; wherein the symmetrical cell is a cell in which the positive and negative electrodes use the same electrode material, the symmetrical cell includes an electrolyte and two preset electrodes, the solid-phase diffusion coefficient of the preset electrodes being greater than a preset coefficient value; and determining the liquid-phase diffusion coefficient of the electrolyte based on the relaxation voltages at multiple acquisition times.

[0006] In the technical solution of this application embodiment, since the solid-phase diffusion coefficient of the preset electrode is greater than the preset coefficient value, the solid-phase diffusion and liquid-phase diffusion can be decoupled, eliminating the interference of electrode solid-phase diffusion on the test results. Not only can the liquid-phase diffusion coefficient of the electrolyte be directly determined, but this application also applies current to the symmetrical battery and obtains the relaxation voltage, which standardizes the test process, reduces test errors, and improves test stability and consistency of test results.

[0007] In some embodiments, determining the liquid-phase diffusion coefficient of the electrolyte based on the relaxation voltage at multiple acquisition times includes: determining the logarithm of the relaxation voltage at each acquisition time based on the relaxation voltage at each acquisition time; performing linear fitting on multiple logarithms of relaxation voltage to obtain a fitting curve; and determining the liquid-phase diffusion coefficient of the electrolyte based on a pre-established correspondence between the slope and the diffusion coefficient and the fitting curve. In the technical solution of this application embodiment, obtaining a fitting curve by linear fitting on the logarithm of the relaxation voltage allows for a more intuitive determination of the trend of the logarithm of the relaxation voltage changing over time; and the liquid-phase diffusion coefficient of the electrolyte can be quickly and accurately determined based on the correspondence between the slope of the fitting curve and the diffusion coefficient, thus improving the testing efficiency of the diffusion coefficient.

[0008] In some embodiments, linear fitting is performed based on the logarithms of relaxation voltages corresponding to multiple acquisition times to obtain a fitting curve, including: determining a fitting interval based on the trend of the logarithms of multiple relaxation voltages changing over time; and performing linear fitting based on the logarithms of relaxation voltages within the fitting interval to obtain a fitting curve. In the technical solution of this application embodiment, linear fitting based on the logarithms of relaxation voltages within the fitting interval can obtain a more accurate fitting curve, thereby obtaining a more accurate liquid phase diffusion coefficient based on the fitting curve.

[0009] In some embodiments, the liquid phase diffusion coefficient of the electrolyte is determined based on a pre-established correspondence between the slope and the diffusion coefficient and a fitted curve, including: calculating the slope of the fitted curve; and substituting the slope of the fitted curve into the correspondence to calculate the liquid phase diffusion coefficient of the electrolyte. The technical solution of this application embodiment, by utilizing a pre-established correspondence to calculate the liquid phase diffusion coefficient of the electrolyte, can improve the efficiency of determining the diffusion coefficient, thereby improving the research and development efficiency of the electrolyte.

[0010] In some embodiments, the method further includes: applying a test current to the symmetrical battery multiple times, and acquiring relaxation voltages at multiple acquisition moments after each cessation of the test current application; determining multiple candidate diffusion coefficients based on the relaxation voltages acquired at the multiple acquisition moments; and determining the liquid phase diffusion coefficient of the electrolyte based on the multiple candidate diffusion coefficients. In the technical solution of this application embodiment, by repeating the test multiple times, errors can be reduced and the accuracy of the test results can be improved.

[0011] In some embodiments, determining the liquid phase diffusion coefficient of the electrolyte based on multiple candidate diffusion coefficients includes: calculating the covariance of the multiple candidate diffusion coefficients to obtain a target covariance; and determining the average value of the multiple candidate diffusion coefficients as the liquid phase diffusion coefficient of the electrolyte when the target covariance is less than a preset threshold. In the technical solution of this application embodiment, using covariance to determine test stability can yield a more accurate liquid phase diffusion coefficient, thereby better assisting in the research and development of electrolytes.

[0012] In some embodiments, the method further includes: performing cyclic voltammetric scanning on the electrolyte-encapsulated cell within a preset voltage range until a preset number of cycles is reached to obtain a symmetrical battery. In the technical solution of this application embodiment, the electrolyte-encapsulated cell is processed using voltammetric scanning, which can achieve the effects of removing water and HF and stabilizing the lithium electrode. This processing method mainly controls the battery voltage; therefore, this processing method is relatively stable and has little impact on battery performance.

[0013] In some embodiments, the symmetrical battery further includes an insulating material layer; two preset electrodes are disposed on opposite sides of the insulating material layer; and through holes are provided in the insulating material layer.

[0014] In some embodiments, the symmetrical battery further includes two current collectors; the current collectors are disposed on the side of the preset electrode opposite to the insulating material layer.

[0015] In some embodiments, the material of the preset electrode includes lithium or a lithium alloy; the material of the insulating material layer includes Teflon; and the material of the current collector includes at least one conductive material selected from copper and carbon.

[0016] Secondly, this application also provides a diffusion coefficient determining apparatus, the apparatus comprising:

[0017] The data acquisition module is used to apply a test current to a pre-prepared symmetrical cell and acquire the relaxation voltage at multiple acquisition moments after the test current is stopped; wherein, the symmetrical cell includes an electrolyte and two preset electrodes arranged symmetrically, and the solid-phase diffusion coefficient of the preset electrodes is greater than a preset coefficient value.

[0018] The first coefficient determination module is used to determine the liquid phase diffusion coefficient of the electrolyte based on the relaxation voltage at multiple acquisition times.

[0019] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in any one of the first aspects.

[0020] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in any one of the first aspects.

[0021] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the method of any one of the first aspects. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the alternative 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:

[0023] Figure 1 This is a schematic diagram of the application environment of an embodiment of this application;

[0024] Figure 2 This is a schematic flowchart of a diffusion coefficient determination method according to an embodiment of this application;

[0025] Figure 3 This is a flowchart illustrating the steps of determining the liquid phase diffusion coefficient based on the relaxation voltage according to an embodiment of this application.

[0026] Figure 4a This is a schematic diagram of a voltage curve according to an embodiment of this application;

[0027] Figure 4b This is a schematic diagram of a voltage logarithmic curve according to an embodiment of this application;

[0028] Figure 5 This is a flowchart illustrating the logarithmic fitting step based on the relaxation voltage according to an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of a fitting curve according to an embodiment of this application;

[0030] Figure 7 This is a flowchart illustrating the steps of determining the liquid phase diffusion coefficient based on the slope according to an embodiment of this application;

[0031] Figure 8 This is a flowchart illustrating the repeated testing steps of an embodiment of this application;

[0032] Figure 9 This is a flowchart illustrating the steps of determining the liquid phase diffusion coefficient based on multiple candidate diffusion coefficients according to an embodiment of this application.

[0033] Figure 10 This is a schematic diagram of covariance according to an embodiment of this application;

[0034] Figure 11a This is one of the structural schematic diagrams of a symmetrical battery according to an embodiment of this application;

[0035] Figure 11b This is a schematic diagram of a through-hole in an insulating material layer according to an embodiment of this application;

[0036] Figure 11c This is a second schematic diagram of the structure of a symmetrical battery according to an embodiment of this application;

[0037] Figure 12 This is one of the structural block diagrams of a diffusion coefficient determining device according to an embodiment of this application;

[0038] Figure 13 This is a second structural block diagram of a diffusion coefficient determining device according to an embodiment of this application;

[0039] Figure 14 This is the third structural block diagram of a diffusion coefficient determining device according to an embodiment of this application;

[0040] Figure 15 This is an internal structural diagram of a computer device according to an embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] Preset electrode 601, insulating material layer 602, current collector 603, through hole 604. Detailed Implementation

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] In the description of the embodiments of this application, the term "and / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0048] 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).

[0049] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0050] With the development of new energy technologies, battery manufacturing processes have also advanced rapidly. Parameters of the electrolyte in a battery include conductivity, viscosity, diffusion coefficient, and transport number. These parameters affect battery performance, with the diffusion coefficient having a particularly significant impact on high-rate charge and discharge. A high diffusion coefficient means the battery can cycle more efficiently, reducing safety hazards such as localized overheating and short circuits caused by ion accumulation, thereby improving battery safety. Therefore, accurately evaluating the diffusion coefficient has become one of the main challenges in electrolyte development.

[0051] Currently, the diffusion coefficients determined by existing testing schemes are a combined result of solid-phase diffusion and liquid-phase diffusion, lacking decoupling of solid-phase diffusion and liquid-phase diffusion, as well as schemes for directly testing the liquid-phase diffusion coefficient. Furthermore, the testing process is easily affected by factors such as electrode system selection, electrode wettability, and electrolyte dosage, leading to problems such as poor test stability, large fluctuations in test results, and a lack of reliability.

[0052] To address the aforementioned issues, this application provides a diffusion coefficient determination scheme. This scheme applies a test current to a pre-prepared symmetrical battery and acquires relaxation voltages at multiple sampling points after the test current is stopped. Based on these relaxation voltages, the liquid phase diffusion coefficient of the electrolyte is determined. Since the solid phase diffusion coefficient of the preset electrode in the symmetrical battery of this application is greater than a preset value, solid phase diffusion and liquid phase diffusion can be decoupled, eliminating the interference of electrode solid phase diffusion on the test results. This not only allows for direct determination of the electrolyte's liquid phase diffusion coefficient, but also standardizes the testing process by applying current to the symmetrical battery and acquiring relaxation voltages, reducing test errors and improving test stability and consistency of test results.

[0053] The diffusion coefficient determination method disclosed in the embodiments of this application can be applied to... Figure 1 The application environment shown includes a computer device 101 and a testing device 102, which can communicate via a network. After being connected to the symmetrical battery, the testing device 102, under the control of the computer device 101, can apply a test current to the symmetrical battery, perform cyclic voltammetry scanning, and acquire the relaxation voltage after the applied test current is stopped.

[0054] According to some embodiments of this application, refer to Figure 2 A method for determining the diffusion coefficient is provided, which can be applied to... Figure 1 Taking a computer device as an example, the process can include the following steps:

[0055] Step 201: Apply a test current to the symmetrical cell and acquire the relaxation voltage at multiple acquisition times after stopping the application of the test current.

[0056] A symmetrical battery is a battery in which the positive (cathode) and negative (anode) electrodes use the same electrode material. Compared to traditional batteries, symmetrical batteries have a simpler design, are easier to manufacture, and have lower equipment costs. A symmetrical battery consists of an electrolyte and two pre-set electrodes.

[0057] The solid-phase diffusion coefficient of the preset electrode is greater than a preset coefficient value. Understandably, a larger solid-phase diffusion coefficient indicates less influence from solid-phase diffusion; a smaller solid-phase diffusion polarization will not interfere with the measurement of the liquid-phase diffusion coefficient. Optionally, the preset coefficient value can be 10. -9 m 2 / s. For example, the preset electrode can be a lithium sheet electrode, a lithium alloy electrode, etc., whose main function is to provide lithium ions and eliminate solid-phase diffusion between the electrolyte and the electrode. Alternatively, the preset electrode can be an electrode material with intrinsically non-diffusion processes, such as a metallic lithium electrode, in which case the preset electrode does not involve solid-phase diffusion.

[0058] In the electrolyte development process, a symmetrical battery can be fabricated by assembling a battery cell using pre-designed electrodes and insulating materials, and then injecting the electrolyte into the cell. For example, the pre-designed electrode is a lithium electrode, and the insulating material is Teflon. Lithium electrodes are placed at both ends of a Teflon sheet with through holes, and electrolyte is injected into the through holes of the Teflon sheet to prepare a symmetrical battery.

[0059] After the symmetrical cell is fabricated, a computer device can control a testing device to apply a test current to the symmetrical cell, thereby creating a concentration gradient inside the cell. In some embodiments, the test current is applied for at least 10 seconds to establish a lithium-ion concentration difference between the two lithium electrodes of the symmetrical cell, thus changing the electrode potential difference.

[0060] The test current mentioned above can be a pulse current. A pulse current is a current whose direction remains unchanged but whose intensity changes continuously. It can be considered as a unidirectional current that is periodically interrupted by a series of open circuits (no current flows through it).

[0061] It should be noted that the test current density is less than the electrode limiting diffusion current density, resulting in a smaller lithium-ion concentration difference within the symmetrical cell. Here, current density represents the current per unit area, while the electrode limiting diffusion current density represents the current per unit area corresponding to the establishment of the maximum lithium-ion concentration difference on the preset electrode surface.

[0062] Afterward, when the test current is stopped, a relaxation phenomenon occurs inside the battery, which is the phenomenon of returning from a non-equilibrium state when the test current was applied to an equilibrium state. The test equipment collects data within a preset time period, and the computer equipment can obtain the relaxation voltage at multiple sampling moments within the preset time period from the test equipment. In some embodiments, the relaxation time is greater than 60 seconds, and the data recording sampling frequency is greater than 1Hz.

[0063] The relaxation voltages were recorded sequentially over time, representing the polarization voltages resulting from ohmic polarization, electrochemical polarization, and concentration polarization at the preset electrodes. Ohmic and electrochemical polarization relaxations were completed within one second; therefore, relaxation voltage changes exceeding one second originated from concentration polarization relaxation. Concentration polarization relaxation is achieved by eliminating the concentration gradient through lithium-ion diffusion; thus, relaxation voltages exceeding one second are related to the electrolyte ion diffusion coefficient.

[0064] Ohmic polarization is caused by the intrinsic and contact resistance of components such as the electrolyte, diaphragm, and electrode materials, and has an extremely short response time. Electrochemical polarization, also known as activation polarization, is caused by the electrochemical reaction rate of the active materials at the positive and negative electrodes being less than the rate of electron movement, and has a response time on the order of microseconds. Concentration polarization is caused by the consumption of reactants leading to a decrease in surface concentration or the accumulation of products on the electrode surface leading to an increase in surface concentration, resulting in the electrode potential deviating from the equilibrium value, and has a response time on the order of seconds.

[0065] Step 202: Determine the liquid phase diffusion coefficient of the electrolyte based on the relaxation voltage at multiple sampling times.

[0066] By pre-establishing a correspondence or calculation model between relaxation voltage and liquid phase diffusion coefficient, and after acquiring relaxation voltages at multiple acquisition times, the computer equipment can use the pre-established correspondence and the relaxation voltages at multiple acquisition times to calculate the liquid phase diffusion coefficient of the electrolyte. Alternatively, the relaxation voltages at multiple acquisition times can be substituted into the pre-established calculation model to calculate the liquid phase diffusion coefficient of the electrolyte.

[0067] It should be noted that the method for determining the liquid phase diffusion coefficient is not limited to the above method, and can be set according to the actual situation.

[0068] In the above embodiments, a test current is applied to a pre-prepared symmetrical battery, and relaxation voltages are acquired at multiple sampling moments after the test current is stopped. The liquid phase diffusion coefficient of the electrolyte is determined based on the relaxation voltages at these multiple sampling moments. In the technical solution of this application embodiment, since the solid phase diffusion coefficient of the preset electrode is greater than a preset coefficient value, solid phase diffusion and liquid phase diffusion can be decoupled, eliminating the interference of electrode solid phase diffusion on the test results. This not only allows for the direct determination of the liquid phase diffusion coefficient of the electrolyte, but also standardizes the test process by applying current to the symmetrical battery and acquiring the relaxation voltage, thereby reducing test errors and improving test stability and consistency of test results.

[0069] According to some embodiments of this application, refer to Figure 3 In the above embodiments, "determining the liquid phase diffusion coefficient of the electrolyte based on the relaxation voltage" may include the following steps:

[0070] Step 301: Determine the logarithm of the relaxation voltage at each acquisition time based on the relaxation voltage at each acquisition time.

[0071] Computer equipment can generate voltage curves based on the relaxation voltages at each acquisition time, such as... Figure 4a As shown, the horizontal axis represents the acquisition time in seconds (s), and the vertical axis represents the relaxation voltage in volts (V). The linear trend of the relaxation voltage is not obvious in the figure; therefore, data processing can be performed on the relaxation voltage to more clearly demonstrate the linear trend. In some embodiments, the computer device takes the logarithm of the relaxation voltage at each acquisition time to obtain the logarithm of the relaxation voltage at each acquisition time.

[0072] Step 302: Perform linear fitting based on the logarithms of multiple relaxation voltages to obtain the fitting curve.

[0073] Computer equipment can generate a voltage logarithmic curve based on the relaxation voltage logarithm at each acquisition time, such as... Figure 4b As shown in the figure, the horizontal axis represents the acquisition time in seconds (s), and the vertical axis represents the logarithm of the relaxation voltage in volts (V). The figure shows that the logarithm of the relaxation voltage exhibits a linear trend. By fitting the linearly changing logarithm of the relaxation voltage to a straight line, a fitting curve can be obtained.

[0074] Step 303: Determine the liquid phase diffusion coefficient of the electrolyte based on the pre-established correspondence between the slope and the diffusion coefficient and the fitting curve.

[0075] Since the relaxation voltage is related to the electrolyte ion diffusion coefficient, and the slope of the fitted curve reflects the trend of the logarithm of the relaxation voltage, a correspondence between the slope and the diffusion coefficient can be established in advance. After obtaining the fitted curve, the slope of the fitted curve is determined. Based on the slope and the above correspondence, the liquid phase diffusion coefficient of the electrolyte can be determined.

[0076] In the above embodiments, the logarithm of the relaxation voltage at each acquisition time is determined based on the relaxation voltage at each acquisition time; a fitting curve is obtained by linear fitting of multiple logarithms of relaxation voltage; and the liquid phase diffusion coefficient of the electrolyte is determined based on the pre-established correspondence between the slope and the diffusion coefficient and the fitting curve. In the technical solution of this application embodiment, obtaining a fitting curve by linear fitting of the logarithm of relaxation voltage allows for a more intuitive determination of the trend of the logarithm of relaxation voltage changing over time; the liquid phase diffusion coefficient of the electrolyte can be quickly and accurately determined based on the correspondence between the slope of the fitting curve and the diffusion coefficient, thus improving the testing efficiency of the diffusion coefficient.

[0077] According to some embodiments of this application, refer to Figure 5 In the above embodiment, "performing linear fitting based on the logarithms of the relaxation voltages at multiple acquisition times to obtain a fitting curve" may include the following steps:

[0078] Step 3021: Determine the fitting interval based on the trend of the logarithm of multiple relaxation voltages changing over time.

[0079] The computer equipment generates a voltage logarithmic curve based on the relaxation voltage logarithm at each acquisition time, such as... Figure 4b As shown. Then, the interval in the logarithmic voltage curve where the relaxation voltage logarithm changes linearly with time is determined, and this interval is defined as the fitting interval. For example... Figure 4b As shown, the acquisition time of 300s-1500s is defined as the fitting interval.

[0080] Step 3022: Perform linear fitting based on the logarithm of the relaxation voltage within the fitting interval to obtain the fitting curve.

[0081] The logarithm of the relaxation voltage within the fitting interval is fitted to a straight line to obtain the fitting curve, as shown below. Figure 6As shown, the horizontal axis represents the acquisition time in seconds (s), and the vertical axis represents the logarithm of the relaxation voltage in volts (V). In practical applications, various fitting algorithms, simulation software, data processing software, etc., can be used for fitting. This application does not limit the fitting method in its embodiments.

[0082] In the above embodiments, a fitting interval is determined based on the trend of the logarithm of multiple relaxation voltages changing over time; a linear fit is performed on the logarithm of the relaxation voltages within the fitting interval to obtain a fitting curve. In the technical solution of this application embodiment, a more accurate fitting curve can be obtained by performing linear fitting on the logarithm of the relaxation voltages within the fitting interval, thereby obtaining a more accurate liquid phase diffusion coefficient based on the fitting curve.

[0083] According to some embodiments of this application, refer to Figure 7 In the above embodiments, "determining the liquid phase diffusion coefficient of the electrolyte based on the pre-established correspondence between the slope and the diffusion coefficient and the fitting curve" may include the following steps:

[0084] Step 3031: Calculate the slope of the fitted curve.

[0085] After fitting the logarithm of the relaxation voltage within the fitting interval into a straight line, the computer equipment calculates the slope based on the intercepts of the line on the horizontal and vertical axes.

[0086] Step 3032: Substitute the slope of the fitted curve into the corresponding relationship for calculation to obtain the liquid phase diffusion coefficient of the electrolyte.

[0087] The correspondence is shown in formula (1):

[0088] D = −Slope × L 2 / π 2 ----------------------------------(1)

[0089] Where D is the liquid phase diffusion coefficient; L is the distance between the two preset electrodes; and Slope is the slope of the fitted curve.

[0090] After calculating the slope of the fitted curve, the slope is substituted into formula (1) to calculate the liquid phase diffusion coefficient D of the electrolyte.

[0091] In some embodiments, the process of determining the correspondence is as follows:

[0092] The relationship between battery voltage and ion concentration is determined as shown in formula (2):

[0093] ----------------------------------(2)

[0094] Where E is the battery voltage, E 0 Let be the initial voltage, i.e., 0V, R be the gas constant, T be the temperature, n be the lithium-ion charge (e.g., 1), and C1 and C2 be the lithium-ion concentrations on the surfaces of the two electrodes, respectively.

[0095] Since the pulse current is less than the limiting diffusion current, C1 and C2 are not much different from the bulk electrolyte concentration C0, so formula (3) can be obtained:

[0096] -------------------------------(3)

[0097] Substituting formula (3) into formula (2), we can see that E is proportional to ΔC.

[0098] The change of the concentration difference ΔC between the two electrodes during the relaxation process satisfies the following equation:

[0099] ------------(4)

[0100] Where A is a dimensionless coefficient representing the relaxation coefficient at different positions, L is the distance between the two electrodes, and D is the liquid phase diffusion coefficient of the electrolyte.

[0101] when When, formula (4) can take the first term, that is:

[0102] -----------------------(5)

[0103] Taking the logarithm of both sides of formula (5) yields formula (6):

[0104] -------------------(6)

[0105] Where E is proportional to ΔC, denoted as E=k×ΔC, we can obtain the formula:

[0106] ------------------(7)

[0107] Therefore, by plotting ln(E) against t, we can obtain that the slope of the linear region satisfies formula (1).

[0108] In the above embodiments, the slope of the fitted curve is calculated; the slope of the fitted curve is substituted into the corresponding relationship for calculation to obtain the liquid phase diffusion coefficient of the electrolyte. The technical solution of this application embodiment uses a pre-established corresponding relationship to calculate the liquid phase diffusion coefficient of the electrolyte, which can improve the efficiency of determining the diffusion coefficient, thereby improving the research and development efficiency of the electrolyte.

[0109] According to some embodiments of this application, refer to Figure 8 This application may also include the following steps:

[0110] Step 401: Apply test current to the symmetrical cell multiple times, and acquire relaxation voltage at multiple acquisition times after each stop of applying test current.

[0111] The computer equipment can control the testing equipment to apply a test current to a symmetrical battery. Afterward, the testing equipment stops applying the test current and samples the data to obtain the relaxation voltage of one test. By repeating the process of applying current and sampling data multiple times, the testing equipment can obtain the relaxation voltage of multiple tests. The computer equipment can obtain the relaxation voltage at multiple sampling points after each test, or it can obtain the relaxation voltage at multiple sampling points from each test all at once after multiple tests.

[0112] It should be noted that the number of repetitions can be less than 10 times to avoid drastic changes in the surface state of the preset electrode and to prevent lithium dendrite formation from inducing a short circuit in the battery.

[0113] Step 402: Determine multiple candidate diffusion coefficients based on the relaxation voltages obtained at multiple acquisition times.

[0114] For each relaxation voltage obtained in each test, the computer device can determine the logarithm of the relaxation voltage corresponding to each acquisition time according to the relaxation voltage at each acquisition time, as provided in the above embodiments; determine the fitting interval according to the trend of the multiple logarithms of relaxation voltage changing with time; perform linear fitting based on the logarithms of relaxation voltage within the fitting interval to obtain the fitting curve; calculate the slope of the fitting curve; and substitute the slope of the fitting curve into the corresponding relationship for calculation to obtain the candidate diffusion coefficient corresponding to this test.

[0115] By analogy, the candidate diffusion coefficients for each test can be obtained.

[0116] Step 403: Determine the liquid phase diffusion coefficient of the electrolyte based on multiple candidate diffusion coefficients.

[0117] Calculate the mean of multiple candidate diffusion coefficients and determine the mean as the liquid phase diffusion coefficient of the electrolyte. Alternatively, determine the median of multiple candidate diffusion coefficients and determine the median as the liquid phase diffusion coefficient of the electrolyte. Alternatively, perform a weighted summation of multiple candidate diffusion coefficients to obtain the liquid phase diffusion coefficient of the electrolyte; the weight of each candidate diffusion coefficient can be determined based on the test order or the accuracy of historical test data.

[0118] It should be noted that the method for determining the liquid phase diffusion coefficient based on multiple candidate diffusion coefficients is not limited to the above method, and can be set according to the actual situation.

[0119] In the above embodiments, a test current is applied to the symmetrical battery multiple times, and the relaxation voltage is acquired at multiple sampling moments after each application of the test current is stopped. Multiple candidate diffusion coefficients are determined based on the acquired relaxation voltages at the multiple sampling moments. The liquid phase diffusion coefficient of the electrolyte is then determined based on the multiple candidate diffusion coefficients. In the technical solution of this application embodiment, by repeating the test multiple times, errors can be reduced and the accuracy of the test results can be improved.

[0120] According to some embodiments of this application, refer to Figure 9 In the above embodiments, "determining the liquid phase diffusion coefficient of the electrolyte based on multiple candidate diffusion coefficients" may include the following steps:

[0121] Step 501: Calculate the covariance based on multiple candidate diffusion coefficients to obtain the target covariance.

[0122] Here, E[(XE(X))(YE(Y))] is called the covariance of random variables X and Y, and the covariance represents the variance of the population error of the two variables.

[0123] After obtaining multiple candidate diffusion coefficients, the covariance is calculated based on these candidate diffusion coefficients to obtain the target covariance.

[0124] Step 502: If the target covariance is less than a preset threshold, the average value of multiple candidate diffusion coefficients is determined as the liquid phase diffusion coefficient of the electrolyte.

[0125] If the target covariance is less than the preset threshold, it indicates that the test stability meets the requirements. The liquid phase diffusion coefficient determined by multiple candidate diffusion coefficients is more accurate, so the average value of multiple candidate diffusion coefficients is determined as the liquid phase diffusion coefficient of the electrolyte. If the target covariance is greater than or equal to the preset threshold, it indicates that the test stability does not meet the requirements. Then, the process of applying test current, data sampling, and calculating the liquid phase diffusion coefficient is repeated until the target covariance is less than the preset threshold.

[0126] In some embodiments, multiple symmetric cells can be fabricated, and the above tests and calculations are performed on each symmetric cell to obtain the target covariance and liquid phase diffusion coefficient corresponding to each symmetric cell. Figure 10 As shown, the horizontal axis represents the sample number of cells with different symmetries, and the left vertical axis represents the diffusion coefficient, with units of m. 2 / s, with the right vertical axis representing covariance (unitless). As can be seen from the figure, the target covariance for each sample is less than 1%, meeting the testing requirements. Furthermore, the test results among different samples show good consistency, indicating that the method provided in this application can stably test the liquid phase diffusion coefficient.

[0127] In the above embodiments, covariance is calculated based on multiple candidate diffusion coefficients to obtain a target covariance. If the target covariance is less than a preset threshold, the average value of the multiple candidate diffusion coefficients is determined as the liquid phase diffusion coefficient of the electrolyte. In the technical solution of this application embodiment, using covariance to determine test stability can yield a more accurate liquid phase diffusion coefficient, thereby better assisting in the research and development of electrolytes.

[0128] According to some embodiments of this application, the method may further include: performing cyclic voltammetry scanning on a cell encapsulated with electrolyte within a preset voltage range until a preset number of cycles is reached to obtain a symmetrical cell.

[0129] Before testing, a symmetrical battery needs to be prepared. The preparation process may include: setting preset electrodes at both ends of a pre-prepared insulating material layer to obtain a battery cell; or, bonding the preset electrodes with a current collector to obtain a composite part, and then setting the composite part at both ends of the insulating material layer to obtain a battery cell. The insulating material layer has through holes, electrolyte is injected into the through holes of the insulating material layer, and then the battery cell is encapsulated in an aluminum-plastic film.

[0130] Reference Figure 11a The symmetrical battery includes two preset electrodes 601, an insulating material layer 602, and an electrolyte; the two preset electrodes are disposed on opposite sides of the insulating material layer 602; refer to Figure 11b An insulating material layer 602 has a through hole 604; electrolyte is injected into the through hole 604.

[0131] Since the pre-set electrode can provide lithium ions, solid-phase diffusion between the electrolyte and the electrode is eliminated. Therefore, by using the above-mentioned symmetrical cell, solid-phase diffusion and liquid-phase diffusion can be decoupled, thereby directly determining the liquid-phase diffusion coefficient of the electrolyte.

[0132] In some embodiments, refer to Figure 11c The symmetrical battery also includes two current collectors 603; the current collectors 603 are disposed on the side of the preset electrode 601 away from the insulating material layer 602.

[0133] According to some embodiments of this application, the material of the preset electrode includes lithium or lithium alloy; the material of the insulating layer includes Teflon; and the material of the current collector includes at least one conductive material selected from copper and carbon.

[0134] The primary function of the preset electrode is to provide lithium ions and eliminate solid-phase diffusion. The materials for the preset electrode can include lithium, lithium alloys, etc. The primary functions of the insulating material layer are insulation and defining the distance between the two preset electrodes. The insulating material layer can be Teflon or other insulating materials. The primary function of the current collector is to conduct electricity. The materials for the current collector can include conductive materials such as metals and carbon.

[0135] After the electrolyte is injected, the computer controls the testing equipment to perform cyclic voltammetry scans on the electrolyte-encapsulated cells within a preset voltage range until the preset number of cycles is reached to obtain a symmetrical cell. For example, cyclic voltammetry scans are performed within a range of ±0.2V, at a scan rate of 5mV / s, for 20 cycles.

[0136] In the above embodiments, cyclic voltammetry scanning is performed on the battery cell containing electrolyte within a preset voltage range until the preset number of cycles is reached to obtain a symmetrical battery. In the technical solution of this application embodiment, the voltammetry scanning method is used to process the battery cell containing electrolyte, which can achieve the functions of removing water and HF and stabilizing the lithium electrode. This processing method mainly controls the battery voltage; therefore, this processing method is relatively stable and has little impact on battery performance.

[0137] According to some embodiments of this application, a method for determining the diffusion coefficient is provided, which is applied to... Figure 1 Taking a computer device as an example, the process can include the following steps:

[0138] Step 1: Control the testing equipment to perform cyclic voltammetry scanning on the battery cell containing electrolyte within a preset voltage range until the preset number of cycles is reached to obtain a symmetrical battery.

[0139] The symmetrical cell includes an electrolyte and two preset electrodes, the solid-phase diffusion coefficient of which is greater than a preset coefficient value.

[0140] Step 2: Control the test equipment to apply test current to the symmetrical battery multiple times, and acquire the relaxation voltage at multiple acquisition moments after each stop of applying test current.

[0141] Step 3: Determine multiple candidate diffusion coefficients based on the relaxation voltages obtained at multiple acquisition times.

[0142] The process of determining candidate diffusion coefficients may include: determining the logarithm of the relaxation voltage at each acquisition time based on the relaxation voltage at each acquisition time; determining the fitting interval based on the trend of multiple logarithms of relaxation voltage changing over time; performing linear fitting based on the logarithms of relaxation voltage within the fitting interval to obtain a fitting curve; calculating the slope of the fitting curve; and substituting the slope of the fitting curve into the corresponding relationship for calculation to obtain the candidate diffusion coefficients.

[0143] Step 4: Calculate the covariance based on multiple candidate diffusion coefficients to obtain the target covariance.

[0144] Step 5: If the target covariance is less than a preset threshold, the average value of multiple candidate diffusion coefficients is determined as the liquid phase diffusion coefficient of the electrolyte.

[0145] In the above embodiments, the solid-phase diffusion coefficient of the preset electrode is greater than a preset coefficient value. Therefore, solid-phase diffusion and liquid-phase diffusion can be decoupled, eliminating the interference of electrode solid-phase diffusion and other battery structures on the test results, and directly determining the liquid-phase diffusion coefficient of the electrolyte. Repeating the test multiple times and using covariance to determine the test stability standardizes the test process, reduces test errors, and improves test stability and consistency of test results.

[0146] It should be understood that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps.

[0147] Based on the same inventive concept, this application also provides a diffusion coefficient determining apparatus for implementing the diffusion coefficient determining method described above. The solution provided by this apparatus is similar to the implementation described in the above method; therefore, the specific limitations in one or more embodiments of the diffusion coefficient determining apparatus provided below can be found in the limitations of the diffusion coefficient determining method described above, and will not be repeated here.

[0148] According to some embodiments of this application, refer to Figure 12 A diffusion coefficient determining apparatus is provided, the apparatus comprising:

[0149] The data acquisition module 701 is used to apply a test current to a pre-prepared symmetrical battery and acquire the relaxation voltage at multiple acquisition times after the test current is stopped; wherein, the symmetrical battery is a battery in which the positive and negative electrodes use the same electrode material, the symmetrical battery includes an electrolyte and two preset electrodes, and the solid-phase diffusion coefficient of the preset electrodes is greater than a preset coefficient value.

[0150] The first coefficient determination module 702 is used to determine the liquid phase diffusion coefficient of the electrolyte based on the relaxation voltage at multiple acquisition times.

[0151] In some embodiments, the first coefficient determination module 702 is specifically used to determine the logarithm of the relaxation voltage corresponding to each acquisition time based on the relaxation voltage corresponding to each acquisition time; to perform linear fitting based on multiple logarithms of relaxation voltage to obtain a fitting curve; and to determine the liquid phase diffusion coefficient of the electrolyte based on the pre-established correspondence between the slope and the diffusion coefficient and the fitting curve.

[0152] In some embodiments, the first coefficient determination module 702 is specifically used to determine the fitting interval based on the trend of the change of multiple relaxation voltage logarithms over time; and to perform linear fitting based on the relaxation voltage logarithms within the fitting interval to obtain the fitting curve.

[0153] In some embodiments, the first coefficient determination module 702 is specifically used to calculate the slope of the fitted curve; the slope of the fitted curve is substituted into the corresponding relationship for calculation to obtain the liquid phase diffusion coefficient of the electrolyte.

[0154] In some embodiments, refer to Figure 13 The device also includes:

[0155] The data acquisition module 701 is also used to apply test current to the symmetrical battery multiple times and acquire the relaxation voltage at multiple acquisition moments after each stop of the test current application.

[0156] The second coefficient determination module 703 is used to determine multiple candidate diffusion coefficients based on the relaxation voltages at multiple acquisition times obtained multiple times.

[0157] The third coefficient determination module 704 is used to determine the liquid phase diffusion coefficient of the electrolyte based on multiple candidate diffusion coefficients.

[0158] In some embodiments, the third coefficient determination module 705 is specifically used to calculate the covariance based on multiple candidate diffusion coefficients to obtain the target covariance; if the target covariance is less than a preset threshold, the average value of the multiple candidate diffusion coefficients is determined as the liquid phase diffusion coefficient of the electrolyte.

[0159] In some embodiments, refer to Figure 14 The device also includes:

[0160] The scanning module 705 is used to perform cyclic voltammetry scanning on the battery cell containing electrolyte within a preset voltage range until the preset number of cycles is reached to obtain a symmetrical battery.

[0161] In some embodiments, the symmetrical battery further includes an insulating material layer, with two preset electrodes disposed on opposite sides of the insulating material layer; through holes are provided in the insulating material layer; and electrolyte is injected into the through holes.

[0162] In some embodiments, the symmetrical battery further includes two current collectors; the current collectors are disposed on the side of the preset electrode opposite to the insulating material layer.

[0163] In some embodiments, the material of the preset electrode includes lithium and lithium alloy;

[0164] The insulating material layer includes Teflon;

[0165] The current collector is made of at least one conductive material, such as copper or carbon.

[0166] Each module in the aforementioned diffusion coefficient determining device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the electronic device in hardware form or independent of it, or stored in the memory of the electronic device in software form, so that the processor can call and execute the operations corresponding to each module.

[0167] According to some embodiments of this application, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 15As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, NFC (Near Field Communication), or other technologies. When executed by the processor, the computer program implements a diffusion coefficient determination method. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0168] Those skilled in the art will understand that Figure 15 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0169] According to some embodiments of this application, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory including instructions that can be executed by a processor of an electronic device to perform the above-described method. For example, the non-transitory computer-readable storage medium may be a ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0170] According to some embodiments of this application, a computer program product is also provided, which, when executed by a processor, can implement the above-described methods. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, some or all of the above-described methods can be implemented, wholly or partially, according to the processes or functions described in the embodiments of this application.

[0171] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0172] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0173] The embodiments described above merely illustrate several implementation methods of this application to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for determining the diffusion coefficient, characterized in that, The method includes: A test current is applied to a pre-prepared symmetrical cell, and the relaxation voltage at multiple acquisition times is obtained after the test current is stopped; wherein, the symmetrical cell is a cell in which the positive and negative electrodes use the same electrode material, the symmetrical cell includes an electrolyte and two preset electrodes, and the solid-phase diffusion coefficient of the preset electrodes is greater than a preset coefficient value; The liquid phase diffusion coefficient of the electrolyte is determined based on the relaxation voltage at the multiple acquisition times.

2. The method according to claim 1, characterized in that, Determining the liquid phase diffusion coefficient of the electrolyte based on the relaxation voltage at the multiple acquisition times includes: The number of relaxation voltage logs corresponding to each acquisition time is determined based on the relaxation voltage corresponding to each acquisition time. A linear fit is performed on the logarithms of the relaxation voltages to obtain the fitted curve; The liquid phase diffusion coefficient of the electrolyte is determined based on the pre-established correspondence between the slope and the diffusion coefficient and the fitted curve.

3. The method according to claim 2, characterized in that, The step of performing linear fitting based on the logarithms of multiple relaxation voltages to obtain a fitting curve includes: The fitting interval is determined based on the trend of the logarithm of the relaxation voltage over time; The fitting curve is obtained by linearly fitting the logarithm of the relaxation voltage within the fitting interval.

4. The method according to claim 2, characterized in that, The step of determining the liquid-phase diffusion coefficient of the electrolyte based on the pre-established correspondence between the slope and the diffusion coefficient and the fitted curve includes: Calculate the slope of the fitted curve; The slope of the fitted curve is substituted into the corresponding relationship for calculation to obtain the liquid phase diffusion coefficient of the electrolyte.

5. The method according to any one of claims 1-4, characterized in that, The method further includes: A test current is applied to the symmetrical battery multiple times, and the relaxation voltage is acquired at multiple acquisition times after the test current is stopped each time. Multiple candidate diffusion coefficients are determined based on the relaxation voltages acquired at multiple sampling times. The liquid phase diffusion coefficient of the electrolyte is determined based on a plurality of the candidate diffusion coefficients.

6. The method according to claim 5, characterized in that, Determining the liquid phase diffusion coefficient of the electrolyte based on a plurality of candidate diffusion coefficients includes: The target covariance is obtained by calculating the covariance based on the multiple candidate diffusion coefficients. If the target covariance is less than a preset threshold, the average value of the multiple candidate diffusion coefficients is determined as the liquid phase diffusion coefficient of the electrolyte.

7. The method according to claim 1, characterized in that, The method further includes: A cyclic voltammetric scan is performed on the cell containing the electrolyte within a preset voltage range until the preset number of cycles is reached to obtain the symmetrical battery.

8. The method according to claim 1, characterized in that, The symmetrical battery further includes an insulating material layer, and the two preset electrodes are disposed on opposite sides of the insulating material layer; the insulating material layer has through holes; the electrolyte is injected into the through holes.

9. The method according to claim 8, characterized in that, The symmetrical battery also includes two current collectors; the current collectors are disposed on the side of the preset electrode opposite to the insulating material layer.

10. The method according to claim 9, characterized in that, The material of the preset electrode includes lithium and lithium alloy; The insulating material layer is made of Teflon; The current collector is made of at least one conductive material, such as copper or carbon.

11. A diffusion coefficient determining device, characterized in that, The device includes: The data acquisition module is used to apply a test current to a pre-prepared symmetrical battery and acquire relaxation voltages at multiple acquisition times after the test current is stopped; wherein, the symmetrical battery includes an electrolyte and two preset electrodes arranged symmetrically, and the solid-phase diffusion coefficient of the preset electrodes is greater than a preset coefficient value; The first coefficient determination module is used to determine the liquid phase diffusion coefficient of the electrolyte based on the relaxation voltage at the multiple acquisition times.

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

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

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