Electrolyte ion transference number test method, system, device and computer equipment

Abstract

The application relates to an electrolyte ion transference number test method, system, device, computer equipment, storage medium and computer program product. The method comprises the following steps: acquiring test data of test battery groups, the test data comprising voltage change data and current change data of each test battery group in a constant potential polarization state, and first electrochemical impedance spectrum data in the polarization state and second electrochemical impedance spectrum data in an open circuit state; sequentially performing fitting processing and correction processing on the first electrochemical impedance spectrum data and the second electrochemical impedance spectrum data to obtain first battery impedance data and second battery impedance data; and determining ion transference numbers of the test battery groups according to the voltage change data, the current change data, the first battery impedance data and the second battery impedance data. The ion transference numbers determined by the method are more accurate.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method, system, apparatus, computer equipment, storage medium, and computer program product for testing the ion transport number of an electrolyte. Background Technology

[0002] Ion transport number is a parameter used to evaluate ion migration ability. The electrolyte, as a crucial component of lithium-ion batteries, plays a role in ion transport between the positive and negative electrodes. For electrolytes, whether liquid or solid, transport number is an important parameter for evaluating their ion transport capability.

[0003] Taking lithium-ion transference number as an example, it is usually defined as the proportion of the number of migrating ions to the total number of migrating ions in the electrolyte. The performance of lithium-ion batteries can be predicted by testing the lithium-ion transference number of the electrolyte. A higher lithium-ion transference coefficient is beneficial for reducing concentration polarization during charging and discharging, and is of great significance for improving the power density and energy density of lithium-ion batteries.

[0004] Currently, commonly used methods for testing the ion transport number of electrolytes include the constant potential polarization method (also known as the constant potential polarization method). However, the method of testing the ion transport number using the constant potential polarization method suffers from the problem of low accuracy in the test results. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, system, apparatus, computer equipment, computer-readable storage medium, and computer program product for testing electrolyte ion mobility numbers that can improve the accuracy of ion mobility numbers, addressing the aforementioned technical problems.

[0006] Firstly, this application provides a method for testing the ion transport number of an electrolyte. The method includes:

[0007] Acquire test data for the test battery packs. The test data includes voltage and current change data under constant potential polarization state for each test battery pack, as well as first electrochemical impedance spectroscopy data under polarization state and second electrochemical impedance spectroscopy data under open circuit state.

[0008] The first and second electrochemical impedance spectroscopy data were successively fitted and corrected to obtain the first and second cell impedance data.

[0009] Based on voltage change data, current change data, first cell impedance data, and second cell impedance data, the ion migration number of each test battery pack is determined.

[0010] In the technical solution of this application embodiment, unlike the traditional electrolyte ion transport number test method which only considers the electrolyte impedance as the ohmic impedance of the battery, resulting in inaccurate impedance data, accurate battery impedance data can be obtained by sequentially fitting and correcting the electrochemical impedance spectral data under different states. Furthermore, based on the accurate battery impedance data, current change data, and voltage change data, a more accurate ion transport number can be obtained, thus improving the accuracy of the ion transport number.

[0011] In some embodiments, the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data are sequentially fitted and corrected to obtain the first battery impedance data and the second battery impedance data, including:

[0012] Impedance fitting is performed on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data to obtain the first initial cell impedance data and the second initial cell impedance data.

[0013] Based on the preset correction coefficient, the first initial battery impedance data and the second initial battery impedance data are corrected to obtain the corrected first battery impedance data and the second battery impedance data.

[0014] In the technical solution of this application embodiment, unlike the traditional approach of treating electrolyte impedance as ohmic impedance and ignoring the impedance occupied by the separator, the influence of separator impedance is taken into account in the actual test process, and the battery impedance data is corrected by a correction coefficient, so as to obtain a more accurate ion transference number.

[0015] In some embodiments, the first initial battery impedance data includes a first interface impedance and a first ohmic impedance, the second initial battery impedance data includes a second interface impedance and a second ohmic impedance, and the current change data includes an initial current and a steady-state current.

[0016] Based on a preset correction coefficient, the first initial battery impedance data and the second initial battery impedance data are corrected to obtain the corrected first battery impedance data and the second battery impedance data, including:

[0017] The first ohmic impedance and the second ohmic impedance are corrected according to the preset correction coefficient to obtain the first target ohmic impedance and the second target ohmic impedance.

[0018] Based on voltage change data, current change data, first cell impedance data, and second cell impedance data, the ion transport number of each test battery pack was determined, including:

[0019] Based on voltage change data, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance, the ion transport number of each test battery pack is determined.

[0020] In the technical solution of this application embodiment, unlike the traditional approach of treating the electrolyte impedance as ohmic impedance and ignoring the impedance occupied by the membrane, the influence of the membrane impedance is taken into account in the actual test process, and the ohmic impedance is corrected by a correction factor to obtain a more accurate ion transference number.

[0021] In some embodiments, before correcting the first initial battery impedance data and the second initial battery impedance data according to a preset correction coefficient to obtain the corrected first battery impedance data and the second battery impedance data, the method further includes:

[0022] Acquire historical test data of the target battery pack, which includes multiple battery packs with different numbers of separator layers. The historical test data includes historical electrochemical impedance spectroscopy data of each battery pack in the open circuit state.

[0023] By fitting the historical electrochemical impedance spectroscopy data, multiple sets of ohmic impedances were obtained.

[0024] Linear parameters are obtained by linearly fitting multiple sets of ohmic impedances;

[0025] Determine the preset correction coefficients based on the linear parameters.

[0026] In the technical solution of this application embodiment, by linearly fitting the ohmic impedance in historical test data, a relatively accurate correction coefficient can be obtained simply and effectively, so as to obtain a more accurate ion transference number.

[0027] In some embodiments, before determining the ion migration number of each test battery pack based on voltage change data, current change data, first battery impedance data, and second battery impedance data, the method further includes:

[0028] The voltage in the voltage change data is corrected to obtain the target polarization voltage;

[0029] Based on voltage change data, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance, the ion transport number of each test battery pack is determined. The determination of the ion transport number of each test battery pack includes:

[0030] Based on the target polarization voltage, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance, the ion transference number of each test battery pack is determined.

[0031] In the technical solution of this application embodiment, by correcting the polarization voltage, a more realistic polarization voltage is obtained, and then the ion transference number is determined based on the more realistic polarization voltage, which makes the measured ion transference number more accurate.

[0032] In some embodiments, voltage change data includes open-circuit voltage;

[0033] The voltage in the voltage change data is corrected to obtain the target polarization voltage, including:

[0034] Determine the average voltage based on voltage change data;

[0035] The target polarization voltage is obtained based on the average voltage and the open-circuit voltage.

[0036] In the technical solution of this application embodiment, by first taking the average value of the voltage value, and then using the difference between the average voltage value and the open circuit voltage as the target polarization voltage, a more accurate and reasonable polarization voltage can be obtained, and further, the measured ion transference number can be made more accurate.

[0037] In some embodiments, the second initial battery impedance data also includes the SEI (Solid Electrolyte Interphase) impedance and the second charge transfer impedance;

[0038] Based on the target polarization voltage, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance, the ion transporter number of each test battery pack is determined. After determining the ion transporter number of each test battery pack, the method further includes:

[0039] The voltage difference of each test battery pack is obtained based on the target polarization voltage, the second ohmic impedance, the SEI impedance, the second charge transfer impedance, and the initial current in the current change data.

[0040] The voltage difference of each test battery pack is compared with the preset voltage difference threshold to filter out abnormal battery packs. Abnormal battery packs are those whose voltage difference is less than the preset voltage difference threshold.

[0041] Test data and ion migration counts of abnormal battery packs were removed.

[0042] In the technical solution of this application embodiment, abnormal battery packs are screened out by voltage difference, and the test data and ion migration number of abnormal battery packs are further eliminated, which can make the test data and test results more realistic.

[0043] Secondly, this application also provides an electrolyte ion transport number testing system, the system including a testing device and a testing control device connected to each other;

[0044] The test control device is used to perform ion mobility number testing of the test device using the method described in the above embodiments, and to obtain the ion mobility number of the test device.

[0045] In the technical solution of this application embodiment, by providing the above-mentioned electrolyte ion mobility number testing system, the electrolyte ion mobility number of the testing device can be measured quickly and accurately.

[0046] In some embodiments, the testing apparatus includes a non-removable battery device.

[0047] In the technical solution of this application embodiment, by designing the test device as a non-removable battery device, that is, without disassembling the battery, the adverse effects of disassembly on subsequent test results are reduced, and more accurate test results are obtained.

[0048] In some embodiments, the battery device includes a separator and an insulating adhesive layer with through holes, the separator being embedded in the through holes, and the difference between the inner diameter and the outer diameter of the insulating adhesive layer being a target value, the target value being used to make the detection area of ​​the coin cell battery device a separator without the insulating adhesive layer covering it.

[0049] In the technical solution of this application embodiment, by providing a battery device in which the separator is embedded in the through hole of the insulating adhesive layer and the difference between the inner diameter and the outer diameter of the insulating adhesive layer is a specific target value, the effective detection area of ​​the button battery device is the separator without the insulating adhesive layer, achieving the effect of perfect symmetry of the positive and negative electrode plates, thereby improving the accuracy and consistency of the ion mobility number test results.

[0050] In some embodiments, the test control device is further configured to perform electrochemical impedance spectroscopy testing on the test device at a test frequency not lower than the target cutoff frequency, the target cutoff frequency being used to maintain the steady state of the test device.

[0051] In the technical solution of this application embodiment, by setting the target cutoff frequency, both the phase ohmic impedance and interface impedance can be completely tested, and the influence of Faraday current on the test results can be effectively reduced.

[0052] Thirdly, this application also provides an electrolyte ion mobility number testing device. The device includes:

[0053] The data acquisition module is used to acquire test data of the test battery pack. The test data includes voltage change data and current change data of each test battery pack under constant potential polarization state, as well as first electrochemical impedance spectroscopy data under polarization state and second electrochemical impedance spectroscopy data under open circuit state.

[0054] The data processing module is used to perform fitting and correction processing on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data in sequence to obtain the first battery impedance data and the second battery impedance data.

[0055] The ion mobility number determination module is used to determine the ion mobility number of each test battery pack based on voltage change data, current change data, first battery impedance data, and second battery impedance data.

[0056] Fourthly, this application also provides a computer device. The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps in the above-described electrolyte ion transport number testing method.

[0057] Fifthly, this application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, which, when executed by a processor, implements the steps in the above-described electrolyte ion transport number testing method.

[0058] Sixthly, this application also provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the steps in the above-described electrolyte ion transport number testing method.

[0059] 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

[0060] 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:

[0061] Figure 1 This is a diagram illustrating the application environment of the electrolyte ion transport number testing method in some embodiments of this application;

[0062] Figure 2 This is a flowchart illustrating the electrolyte ion transport number testing method in some embodiments of this application;

[0063] Figure 3 This is a flowchart illustrating the electrolyte ion transport number testing method in other embodiments of this application;

[0064] Figure 4This is a flowchart illustrating the electrolyte ion transport number testing method in some embodiments of this application;

[0065] Figure 5 This is a detailed flowchart illustrating the electrolyte ion transport number testing method in some embodiments of this application;

[0066] Figure 6 This is a detailed flowchart illustrating the electrolyte ion transport number testing method in some embodiments of this application;

[0067] Figure 7 This is a partial structural schematic diagram of the button battery device in some embodiments of this application;

[0068] Figure 8 This is a schematic diagram of the electrolyte ion transport number testing system in some embodiments of this application;

[0069] Figure 9 This is a structural block diagram of the electrolyte ion transport number testing device in some embodiments of this application;

[0070] Figure 10 This is a structural block diagram of the electrolyte ion transport number testing device in some other embodiments of this application;

[0071] Figure 11 This is a diagram showing the internal structure of a computer device in some embodiments of this application. Detailed Implementation

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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).

[0078] Ion transport number is a parameter used to evaluate the ability of ions to migrate. The electrolyte, as a crucial component of a battery, plays a role in ion transport between the positive and negative electrodes. For electrolytes, whether liquid or solid, transport number is an important parameter for evaluating their ion transport capabilities.

[0079] Taking lithium-ion transference number as an example, it is usually defined as the proportion of the number of migrating ions to the total number of migrating ions in the electrolyte. The operation of a lithium-ion battery involves the insertion and extraction of lithium ions at the positive and negative electrodes. During the charging and discharging process of a lithium-ion battery, cations and anions migrate between the positive and negative electrodes, where Li... + Positively charged molecules will migrate towards the negative electrode under the influence of an electric field; Li in the electrolyte... + The migration coefficient is closely related to the insertion and extraction of lithium ions on both the positive and negative electrode sides. The performance of lithium-ion batteries can be predicted by testing the lithium-ion migration number in the electrolyte. A high migration coefficient is of great significance for improving the power density and energy density of lithium-ion batteries.

[0080] The traditional potentiostatic polarization method for ion transference number testing typically involves first performing EIS (Electrochemical Impedance Spectroscopy) on the test battery pack, followed by potentiostatic polarization testing, and finally, EIS testing again under polarized conditions. However, this process introduces a significant instantaneous current, leading to inaccuracies in the measured initial current. Furthermore, to maintain a steady state during testing, a polarization voltage of 10 mV is generally used, and the transference number is usually calculated by directly substituting this 10 mV value into the formula. However, in actual testing, due to the influence of the electrochemical workstation channels or the battery assembly system, the open-circuit voltage of the test battery is often not 0 mV, and the actual voltage applied to the battery is often not equal to 10 mV. Therefore, the measured lithium-ion transference numbers are often inaccurate.

[0081] To improve the accuracy of ion mobility number test results, the battery impedance data in the test data can be corrected, and then the ion mobility number of each test battery pack can be determined based on the corrected battery impedance data, which can make the ion mobility number more accurate.

[0082] Based on the above considerations, this application provides a method for testing the ion transport number of an electrolyte, specifically including: acquiring test data of a test battery pack, including voltage and current change data under constant potential polarization, first electrochemical impedance spectroscopy (EIS) data under polarization, and second EIS data under open circuit conditions; then, sequentially fitting and correcting the first and second EIS data to obtain first and second battery impedance data; and determining the ion transport number of each test battery pack based on the voltage change data, current change data, first and second battery impedance data. This method differs from the traditional approach of treating only the electrolyte impedance as the ohmic impedance of the battery, which leads to inaccurate impedance data. By sequentially fitting and correcting the EIS data before and after polarization, accurate battery impedance data can be obtained. Furthermore, based on the accurate battery impedance data, current change data, and voltage change data, a more accurate ion transport number can be obtained, improving the accuracy of the ion transport number.

[0083] The ion mobility number testing method provided in this application embodiment can be applied to, for example... Figure 1In the application environment shown, the test battery pack 102 is interconnected with the test control device 104. The test control device 104 acquires test data from the test battery pack, including voltage and current change data under constant potential polarization, first electrochemical impedance spectroscopy (EIS) data under polarization, and second EIS data under open circuit conditions. Then, the first and second EIS data are sequentially fitted and corrected to obtain first and second battery impedance data. Finally, based on the voltage change data, current change data, first and second battery impedance data, the ion transport number of each test battery pack is determined. The test battery pack 102 comprises multiple battery packs, which can be general-purpose batteries such as lithium batteries or coin cells. The test data can be obtained directly from the test control device 104 testing the test battery pack 102, or it can be obtained from other testing instruments, depending on the actual situation. The test control device 104 is a device with data processing capabilities.

[0084] In some embodiments, such as Figure 2 As shown, a method for testing the transport number of ions in an electrolyte is provided, which can be applied to... Figure 1 Taking the test control device in the example, the following steps are included:

[0085] Step S100: Obtain test data for the test battery pack. The test data includes voltage change data and current change data under constant potential polarization state for each test battery pack, as well as first electrochemical impedance spectroscopy data under polarization state and second electrochemical impedance spectroscopy data under open circuit state.

[0086] The number of test battery packs can be multiple, and they can also be symmetrical battery systems. The symmetrical battery system in the test battery pack can be a general-purpose battery, such as a reusable battery, or a disposable battery, such as a coin cell. In this embodiment, taking the lithium-ion transference number test as an example, the test battery pack can be a lithium battery pack. Voltage change data refers to the voltage changing over time, i.e., the voltage measured at each time point, including open-circuit voltage and polarization voltage. Current change data refers to the current changing over time, i.e., the current measured at each time point. Electrochemical impedance spectroscopy (EIS) data is the test data obtained by performing EIS testing on the test battery pack. In this embodiment, the second electrochemical impedance spectroscopy data refers to the EIS data obtained by performing EIS testing on the test battery pack in the polarized state after performing a constant potential polarization test on the test battery pack. The second electrochemical impedance spectroscopy data refers to the EIS data collected by performing EIS testing on the test battery in the open-circuit state.

[0087] In practical applications, the test battery pack can first be left to stand for a period of time, such as 10 seconds. Then, a constant potential polarization test can be performed on the test battery pack using a commonly used test voltage, such as 10mV, for 10 minutes. During this process, voltage-time change data and current-time change data can be collected. Next, an EIS test can be performed on the test battery pack under the 10mV polarization state. In this embodiment, the test frequency of the EIS test can be 300MHz~1Hz. During this process, the first electrochemical impedance spectroscopy data of each battery pack in the polarization state can be measured. Then, the battery pack can be left to stand for a period of time, such as 30 minutes, to allow the battery to return to a steady state under open circuit conditions. The EIS test can then be performed on the test battery pack again. During this process, the second electrochemical impedance spectroscopy data of each battery pack in the open circuit state can be measured. After performing ion mobility number tests on the test battery pack according to the above test procedure, the test data can be sent to the test control device. In specific implementations, the test data can be collected by the test control device itself during the test, or it can be sent to the test control device by an external detection device. External testing devices can send test data to the test control device in real time, or they can send the obtained test data to the test control device in a unified manner after the test is completed.

[0088] Step S200: The first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data are successively fitted and corrected to obtain the first battery impedance data and the second battery impedance data.

[0089] After obtaining the first and second electrochemical impedance spectroscopy (EIS) data, they can be fitted and corrected sequentially. Specifically, the fitting process can involve calling a corresponding fitting tool to fit the first and second EIS data, and then correcting the impedance in the fitted EIS data to obtain more accurate first and second battery impedance data.

[0090] Step S300: Determine the ion migration number of each test battery pack based on voltage change data, current change data, first battery impedance data, and second battery impedance data.

[0091] Following the above embodiments, after obtaining the aforementioned test data, the ion mobility number of each test battery group can be determined based on the ion mobility number testing principle, using voltage change data, current change data, first battery impedance data, and second battery impedance data. In specific implementation, the ion mobility number of each test battery group can be determined on a per-test-battery-group basis, using voltage change data, current change data, first electrochemical impedance spectroscopy data, and second electrochemical impedance spectroscopy data.

[0092] In the technical solution of this application embodiment, unlike the traditional electrolyte ion transport number test method which only considers the electrolyte impedance as the ohmic impedance of the battery, resulting in inaccurate impedance data, accurate battery impedance data can be obtained by sequentially fitting and correcting the electrochemical impedance spectral data under different states. Furthermore, based on the accurate battery impedance data, current change data, and voltage change data, a more accurate ion transport number can be obtained, thus improving the accuracy of the ion transport number.

[0093] like Figure 3 As shown, in some embodiments, step S200 includes: step S220, performing impedance fitting processing on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data to obtain the first initial battery impedance data and the second initial battery impedance data.

[0094] Step S240: According to the preset correction coefficient, the first initial battery impedance data and the second initial battery impedance data are corrected to obtain the corrected first battery impedance data and the second battery impedance data.

[0095] In this embodiment, impedance fitting can be performed on the first and second electrochemical impedance spectroscopy (EIS) data using a fitting tool to obtain first and second initial battery impedance data. These first and second initial battery impedance data can be represented as first and second EIS curves. The first EIS curve includes data such as the first interface impedance, first ohmic impedance, and first charge transfer impedance after polarization. The second EIS data includes data such as the second interface impedance, second ohmic impedance, and second charge transfer impedance before polarization.

[0096] In actual testing, since membrane impedance is often difficult to measure directly, its influence on ion mobility number testing is often ignored. Therefore, this embodiment proposes a method to correct the first and second initial battery impedance data. Specifically, the first and second initial battery impedance data can be corrected according to a preset correction coefficient to obtain corrected first and second battery impedance data.

[0097] In the technical solution of this application embodiment, unlike the traditional approach of treating electrolyte impedance as ohmic impedance and ignoring the impedance occupied by the separator, the influence of separator impedance is taken into account in the actual test process, and the battery impedance data is corrected by a correction coefficient, so as to obtain a more accurate ion transference number.

[0098] In some embodiments, such as Figure 4 As shown, step S220 includes step S222, which involves performing impedance fitting processing on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data to obtain the first initial cell impedance data and the second initial cell impedance data. The first initial cell impedance data includes the first interface impedance and the first ohmic impedance, and the second initial cell impedance data includes the second interface impedance and the second ohmic impedance. The current change data includes the initial current and the steady-state current.

[0099] Step S240 includes: Step S242, correcting the first ohmic impedance and the second ohmic impedance according to a preset correction coefficient to obtain the first target ohmic impedance and the second target ohmic impedance.

[0100] Step 300 includes: Step S320, determining the ion migration number of each test battery pack based on voltage change data, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance.

[0101] As shown in the above embodiments, the typical testing process often ignores the influence of the separator impedance on the test and treats the electrolyte impedance as an ohmic impedance. Therefore, in this embodiment, the first ohmic impedance and the second ohmic impedance can be corrected according to a preset correction coefficient to obtain the first target ohmic impedance and the second target ohmic impedance. Then, the polarization voltage in the voltage change data and the initial current and steady-state current in the current change data are extracted, and the ion mobility number is determined for each test battery pack by combining the ion mobility number test principle. Taking the lithium ion mobility number test as an example, the lithium ion mobility number can be determined in the following way:

[0102] Extracting the initial current from the current change data With steady-state current If the effect of interface impedance on the testing process is not considered, then the lithium-ion mobility number... for:

[0103] (1)

[0104] If we only consider the effect of interface impedance on the testing process, then:

[0105] (2)

[0106] (3)

[0107] In the formula, The second interface impedance before polarization. The first interface impedance after polarization. The polarization voltage used for testing. This is the electrolytic cell constant (length / surface area). The conductivity of the electrolyte.

[0108] If we consider the effects of both interface impedance and ohmic impedance on the testing process, then we have:

[0109] (4)

[0110] (5)

[0111] In the formula, The second ohmic impedance was measured during the EIS test before polarization. This is the first ohmic impedance measured during the EIS test after polarization.

[0112] Combining formulas (1), (4), and (5), we have:

[0113] (6)

[0114] In this embodiment, considering the influence of diaphragm impedance on the testing process, a correction factor z is introduced, then:

[0115] (7)

[0116] In practice, the test battery pack can be used as a unit. For each test battery pack, its corresponding polarization voltage, initial current, steady-state current, first interface impedance, first ohmic impedance, second interface impedance and second ohmic impedance are substituted into formula (7) to obtain the ion transference number of each test battery pack.

[0117] In the technical solution of this application embodiment, unlike the traditional approach of treating the electrolyte impedance as ohmic impedance and ignoring the impedance occupied by the membrane, the influence of the membrane impedance is taken into account in the actual test process, and the ohmic impedance is corrected by a correction factor to obtain a more accurate ion transference number.

[0118] like Figure 5 As shown, in some embodiments, before step S242, the method further includes: step S230, acquiring historical test data of the target battery pack, the target battery pack including multiple battery packs with different numbers of separator layers, the historical test data including historical electrochemical impedance spectral data of each battery pack in the open circuit state, fitting the historical electrochemical impedance spectral data to obtain multiple sets of ohmic impedance, linearly fitting the multiple sets of ohmic impedance to obtain linear parameters, and determining a preset correction coefficient based on the linear parameters.

[0119] This embodiment further explains how to determine the correction coefficient. Specifically, it can first perform EIS testing at open-circuit voltage on symmetrical cells containing different numbers of separators, such as 1, 3, 5, and 7 layers. The test frequency can be 300MHz~100mHz. Historical test data obtained from the above EIS test is collected. Then, the ohmic impedance of each test cell group in the historical test data is extracted, and the extracted ohmic impedance is fitted as follows:

[0120] (8)

[0121] By fitting the data, linear parameters a and b are obtained. Then, based on the linear parameters a and b, the correction coefficient z is determined. The method for determining the correction coefficient z based on the fitted parameters a and b can be as follows:

[0122] (9)

[0123] After extensive practical testing, and by processing the test data using formulas (8) and (9), we can obtain: In this embodiment, the correction coefficient can be... .

[0124] In the technical solution of this application embodiment, by linearly fitting the ohmic impedance in historical test data, a relatively accurate correction coefficient can be obtained simply and effectively, so as to obtain a more accurate ion transference number.

[0125] like Figure 5 As shown, in some embodiments, before step S300, the method further includes: step S260, correcting the voltage in the voltage change data to obtain the target polarization voltage.

[0126] Step S320 includes: Step S322, determining the ion migration number of each test battery pack based on the target polarization voltage, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance and second target ohmic impedance.

[0127] The target polarization voltage refers to the true polarization voltage of each test battery pack during the testing process, after correction. Currently, a polarization voltage of 10mV is generally used in ion mobility number testing to ensure the battery maintains a steady state as much as possible during the test. In subsequent ion mobility number calculations, the 10mV voltage value is usually directly substituted into the corresponding calculation formula to obtain the ion mobility number. However, in actual testing, due to the influence of the electrochemical workstation channel or the battery assembly system, the open-circuit voltage of the test battery is often not 0mV, and the applied true voltage is often not equal to 10mV. Moreover, the true voltage value is closely related to the test battery. If the ion mobility number is directly calculated from the applied polarization voltage, it will lead to a deviation between the final measured ion mobility number and the true value. Therefore, in this embodiment, the polarization voltage of each test battery pack can be individually corrected to obtain the true target polarization voltage. Specifically, the correction method includes, but is not limited to, taking the average or maximum voltage value, or other correction processing.

[0128] Once the target polarization voltage is obtained, the polarization voltage in the above formula (7) can be used. Replace with target polarization voltage Furthermore, taking the test battery pack as a unit, for each test battery pack, the target polarization voltage, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance and second target ohmic impedance are substituted into formula (7) to determine the ion transference number of each test battery pack.

[0129] In the technical solution of this application embodiment, by correcting the polarization voltage, a more realistic polarization voltage is obtained, and then the ion transference number is determined based on the more realistic polarization voltage, which makes the measured ion transference number more accurate.

[0130] In some embodiments, voltage change data includes open-circuit voltage;

[0131] like Figure 6 As shown, step S260 includes: step S262, determining the average voltage based on voltage change data, and obtaining the target polarization voltage based on the average voltage and the open-circuit voltage.

[0132] In practical applications, voltage change data includes open-circuit voltage, which can be positive or negative. During actual testing, the open-circuit voltage of the battery pack may be negative. Therefore, in this embodiment, the polarization voltage is corrected based on the voltage change data to obtain the target polarization voltage. This can be achieved by calculating the average voltage value from each voltage value in the voltage change data, and then obtaining the target polarization voltage based on the average voltage value and the open-circuit voltage value.

[0133] Specifically, record the open-circuit voltage value of the test battery pack under open-circuit conditions. The average value of the voltage recorded during the test is recorded as . The actual target polarization voltage is :

[0134] (10)

[0135] In the technical solution of this application embodiment, by first taking the average value of the voltage value, and then using the difference between the average voltage value and the open circuit voltage as the target polarization voltage, a more accurate and reasonable polarization voltage can be obtained, and further, the measured ion transference number can be made more accurate.

[0136] In some embodiments, the second initial battery impedance data also includes the SEI impedance and the second charge transfer impedance;

[0137] like Figure 6 As shown, after step S322, the method further includes: step S400, obtaining the voltage difference of each test battery group based on the target polarization voltage, the second ohmic impedance, the SEI impedance, the second charge transfer impedance and the initial current in the current change data, comparing the voltage difference of each test battery group with a preset voltage difference threshold, screening out abnormal battery groups, which are battery groups with voltage differences less than the preset voltage difference threshold, and removing the test data and ion migration number of abnormal battery groups.

[0138] In practical applications, test data is often affected by various factors, leading to anomalies in the test data of different battery packs. Therefore, the measured test data and results can be filtered to identify these anomalies. In this embodiment, anomalies are identified by the voltage difference between each test battery pack. Specifically, the voltage in the voltage change data can be corrected using the method described in the above embodiment for determining the target polarization voltage, thus obtaining the target polarization voltage. Then, the second electrochemical impedance spectroscopy data is fitted to extract the second ohmic impedance, SEI impedance, and second charge transfer impedance. Based on the target polarization voltage, the second ohmic impedance, SEI impedance, second charge transfer impedance, and initial current, the voltage difference is obtained. Specifically, the voltage difference can be determined using the following formula:

[0139] (11)

[0140] in, For voltage difference, For the target polarization voltage, The second ohmic impedance is obtained by EIS testing under non-polarized conditions. For SEI impedance, This is the second charge transfer impedance.

[0141] Normally, the voltage difference is calculated using formula (11). After multiple tests, it was found that if a certain test battery pack When the voltage is less than 1.0mV, the test data of this battery pack often deviates significantly from the test data of other parallel battery packs. If the voltage difference is greater than or equal to 1.0mV, the test data of this test battery pack shows good consistency with the test data of other parallel test battery packs. Therefore, in this embodiment, the voltage difference threshold can be set to 1.0mV. It is understood that in other embodiments, the voltage difference threshold can also be 1.1mV, 1.2mV, or other values, which can be determined according to the actual situation and are not limited here.

[0142] After determining the voltage difference of each test battery pack, the voltage difference can be compared with a preset voltage threshold of 1.0mV. If the voltage difference is greater than or equal to 1.0mV, it indicates that the test data of this test battery pack has good consistency with the test data of other test battery packs, and no processing is required. If the voltage difference is less than 1.0mV, the test battery packs with voltage differences less than 1.0mV are selected and marked as abnormal battery packs. The corresponding test data and ion migration number of the abnormal battery packs are then deleted.

[0143] In the technical solution of this application embodiment, abnormal battery packs are screened out by voltage difference, and the test data and ion migration number of abnormal battery packs are further eliminated, which can make the test data and test results more realistic.

[0144] In the technical solution of this application embodiment, the verification data obtained by testing the test battery pack with the verification voltage is used to achieve cross-testing and verification of the test data and ion mobility number of the test battery pack, which ensures the consistency and repeatability of the test data and test results, and is more realistic and accurate.

[0145] To provide a clearer explanation of the electrolyte ion transport number testing method provided in this application, the following is in conjunction with the appendix. Figure 6 and one A specific embodiment will be described below, which includes the following steps:

[0146] Step S100: Obtain test data for the test battery pack. The test data includes voltage change data and current change data under constant potential polarization state for each test battery pack, as well as first electrochemical impedance spectroscopy data under polarization state and second electrochemical impedance spectroscopy data under open circuit state.

[0147] Step S222: Impedance fitting processing is performed on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data to obtain the first initial cell impedance data and the second initial cell impedance data. The first initial cell impedance data includes the first interface impedance and the first ohmic impedance, and the second initial cell impedance data includes the second interface impedance and the second ohmic impedance. The current change data includes the initial current and the steady-state current.

[0148] Step S230: Obtain historical test data of the target battery pack. The target battery pack includes multiple battery packs with different numbers of separator layers. The historical test data includes historical electrochemical impedance spectroscopy data of each battery pack in the open circuit state. Fit the historical electrochemical impedance spectroscopy data to obtain multiple sets of ohmic impedances. Perform linear fitting on the multiple sets of ohmic impedances to obtain linear parameters. Determine the preset correction coefficient based on the linear parameters.

[0149] Step S242: Correct the first ohmic impedance and the second ohmic impedance according to the preset correction coefficient to obtain the first target ohmic impedance and the second target ohmic impedance.

[0150] Step S262: Based on the voltage change data, determine the average voltage value, and obtain the target polarization voltage based on the average voltage value and the open-circuit voltage.

[0151] Step S322: Determine the ion transference number of each test battery pack based on the target polarization voltage, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance.

[0152] Step S400: Based on the target polarization voltage, the second ohmic impedance, the SEI impedance, the second charge transfer impedance, and the initial current in the current change data, obtain the voltage difference of each test battery group. Compare the voltage difference of each test battery group with a preset voltage difference threshold, and screen out abnormal battery groups. Abnormal battery groups are those with a voltage difference less than the preset voltage difference threshold. Remove the test data and ion migration number of abnormal battery groups.

[0153] Specifically, the test voltage is taken as 10mV. The voltage difference threshold can be 1.0mV. The allowable error range between the ion transport number and the ion transport number verification value can be ±0.05.

[0154] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to 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 flowcharts of the embodiments described 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 of other steps.

[0155] Currently, in the field of electrolyte ion mobility number testing, the test results are often inaccurate. One significant contributing factor is the defective testing device. Commonly used electrolyte ion mobility number testing devices are typically reusable electrolytic cells, creating a dilemma regarding sealing and disassembly. Good sealing makes disassembly difficult or may cause permanent damage to the electrolytic cell, leading to errors in subsequent tests; poor sealing allows air to enter the device during testing, causing oxidation of the active material and resulting in inaccurate results. Furthermore, the inaccuracy of electrolyte ion mobility number testing devices also stems from the possibility of imperfect alignment of the positive and negative electrode plates.

[0156] To address the issue of inaccurate electrolyte ion transport number test results, this application also provides a coin cell device for performing electrolyte ion transport number tests.

[0157] like Figure 7 As shown, in some embodiments, this application provides a button cell battery device 100, including a separator 102 and an insulating adhesive layer 104 with through holes. The insulating adhesive layer 104 is provided with through holes, and the separator 102 is embedded in the through holes. The difference between the inner diameter and the outer diameter of the insulating adhesive layer 104 is a target value. The target value is used to make the detection area of ​​the button cell battery device 100 the separator 102 without the insulating adhesive layer 104.

[0158] In this embodiment, the button cell battery device 100 is a non-removable battery assembled using the button cell technology. The separator 102 is a limiting separator, that is, a limiting separator is used to limit the passage. The insulating adhesive layer 104 102 is provided with through holes. In this embodiment, the insulating adhesive layer 104 can be an annular structure with an outer diameter of 18 mm and an inner diameter of 12 mm, attached to both sides of the separator 102 to ensure that the effective detection area of ​​the electrode sheet is the separator 102 without the insulating adhesive layer 104, so as to achieve a perfect symmetry between the positive and negative electrode sheets. The insulating adhesive layer 104 is usually green insulating adhesive. It is understood that in other embodiments, the outer diameter and inner diameter of the insulating adhesive layer 104 are not limited to the above example. In other embodiments, they can also be other sizes, as long as they can satisfy the requirement that the effective detection area of ​​the button cell battery device is the separator 102 without the insulating adhesive layer 104, achieving a perfect symmetry between the positive and negative electrode sheets.

[0159] Specifically, in addition to the insulating adhesive layer 104 and the separator 102, the button cell device also includes a positive electrode casing, a negative electrode casing, a positive electrode sheet, a negative electrode sheet, and catalytic materials, etc. Figure 10 (Not provided). Taking a coin cell lithium battery as an example, the specific assembly process is as follows: place the negative electrode shell, add the filler, compact the filler, add lithium foil, inject 80 μL of electrolyte, add the positioning separator, inject 80 μL of electrolyte, add another lithium foil, attach the positive electrode shell, and finally seal the coin cell. In practice, to ensure that the separator and lithium foil surfaces are fully wetted, after assembly, the battery can be left to stand at room temperature for a period of time, such as 12 hours, before starting the ion migration number test. In this embodiment, to ensure test consistency, the sealing press is uniformly used with a pressure of 500 mPa for sealing the coin cells.

[0160] In the technical solution of this application embodiment, by providing a coin cell device in which the separator is embedded in the through hole of the insulating adhesive layer and the difference between the inner diameter and the outer diameter of the insulating adhesive layer is a specific target value, the effective detection area of ​​the coin cell device is the separator without the insulating adhesive layer, achieving the effect of perfect symmetry of the positive and negative electrode plates, thereby improving the accuracy and consistency of the ion mobility number test results.

[0161] In addition, button cell battery devices can also be made into non-removable disposable battery devices, which can effectively solve the aforementioned contradiction between sealing and disassembly.

[0162] In other embodiments, the filler of the button cell device 100 includes nickel foam.

[0163] In this embodiment, the filler for the button cell device is selected as nickel foam, which has good permeability and filtration properties. Specifically, the diameter of the nickel foam can also be 18 mm. It is understood that in other embodiments, the filler can also be other types of catalytic materials, and the diameter can also be other values, as long as the outer diameter of the insulating adhesive layer is equal.

[0164] In the technical solution of this application embodiment, by selecting nickel foam as the filler for the button cell device, the effect of full contact between the separator and the positive and negative electrode sheets can be achieved.

[0165] like Figure 8 As shown, based on the same inventive concept, this application embodiment also provides an electrolyte ion transport number testing system, the system including a testing device 202 and a testing control device 204 connected to each other;

[0166] The test control device 204 is used to implement the electrolyte ion mobility number test method described in any of the above embodiments to test the ion mobility number of the test device 202 and obtain the ion mobility number of the test device 202.

[0167] In this embodiment, the testing device 202 can be a reusable battery device or a disposable battery device; any device commonly used for testing ion mobility numbers can be used as the testing device. The testing control device 204 can be a device with both data processing and testing capabilities, capable of performing constant potential polarization testing and EIS testing on the testing device 202, and also measuring the ion mobility number based on the test data. Alternatively, it can be a device with only data processing capabilities, receiving test data and verification data transmitted from an external detection device to perform the ion mobility number test. Specifically, the ion mobility number test can be performed using the electrolyte ion mobility number testing method described in any of the above embodiments to obtain the ion mobility number of the testing device 202.

[0168] In the technical solution of this application embodiment, by providing the above-mentioned electrolyte ion mobility number testing system, the electrolyte ion mobility number of the testing device can be measured quickly and accurately.

[0169] In some embodiments, the test apparatus 202 includes a non-removable battery device.

[0170] In this embodiment, the testing device 202 can be a non-removable battery device. For example, it can be a non-removable battery device assembled using the coin cell process.

[0171] In the technical solution of this application embodiment, by designing the test device as a non-removable battery device, that is, without disassembling the battery, the adverse effects of disassembly on subsequent test results are reduced, and more accurate test results are obtained.

[0172] In other embodiments, the test device 202 may also be a button battery device as described in any of the above embodiments, which will not be repeated here.

[0173] In the technical solution of this application embodiment, by using a coin cell device as a testing device, the accuracy and consistency of ion mobility number test results can be further improved.

[0174] In some embodiments, the test control device 204 is further configured to perform electrochemical impedance spectroscopy on the test device 202 at a test frequency not lower than the target cutoff frequency, the target cutoff frequency being used to maintain the steady state of the test device.

[0175] Currently, the commonly used EIS test frequency is 300MHz~100mHz. However, research has found that when the EIS test frequency is less than 1Hz, a large Faraday current will exist during the test, which will have a significant impact on the solid-liquid interface impedance. Therefore, the cutoff frequency of the EIS test can be adjusted. In this embodiment, the target cutoff frequency can be 1Hz, and the EIS test frequency used can be 300MHz~1Hz. It is understood that in other embodiments, the target cutoff frequency can also be other values ​​such as 1.1Hz, 1.01Hz, etc., which can be determined according to the actual situation, as long as the steady state of the test device can be maintained. In specific implementation, the test control device 204 can directly perform EIS testing on the test device 202 according to the preset EIS test frequency, or the test control device 204 can send a test signal carrying the EIS test frequency to an external detection device, so that the external detection device can perform EIS testing on the test device 202 according to the corresponding EIS test frequency.

[0176] In practice, the testing device can be tested according to the following testing procedure:

[0177] ① Let it stand still for a period of time, such as 10 seconds;

[0178] ② Constant potential polarization test, test parameters: polarization voltage 10mV vs. Eoc, test duration 10 minutes, collect current change data and voltage change data during this process;

[0179] ③ EIS test, test parameters: polarization voltage 10mV vs. Eoc, test frequency 300MHz~1Hz (i.e. EIS test is performed under 10mV polarization state), and the first electrochemical impedance spectroscopy data are collected during this process.

[0180] ④ Let it stand for 30 minutes;

[0181] ⑤ EIS test, test parameters: 0mV vs. Eoc, test frequency: 300MHz~1Hz (EIS test is performed in open circuit state), and second electrochemical impedance spectroscopy data are collected.

[0182] In the technical solution of this application embodiment, by setting the target cutoff frequency, both the phase ohmic impedance and interface impedance can be completely tested, and the influence of Faraday current on the test results can be effectively reduced.

[0183] Based on the same inventive concept, this application also provides an electrolyte ion mobility number testing device for implementing the above-described electrolyte ion mobility number testing method. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more electrolyte ion mobility number testing device embodiments provided below can be found in the limitations of the electrolyte ion mobility number testing method described above, and will not be repeated here.

[0184] In some embodiments, such as Figure 9 As shown, an electrolyte ion transport number testing device is provided, comprising: a data acquisition module 710, a data processing module 720, and an ion transport number determination module 730, wherein:

[0185] The data acquisition module 710 is used to acquire test data of the test battery pack. The test data includes voltage change data and current change data of each test battery pack under constant potential polarization state, as well as first electrochemical impedance spectroscopy data under polarization state and second electrochemical impedance spectroscopy data under open circuit state.

[0186] The data processing module 720 is used to perform fitting and correction processing on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data in sequence to obtain the first battery impedance data and the second battery impedance data.

[0187] The ion migration number determination module 730 is used to determine the ion migration number of each test battery pack based on voltage change data, current change data, first battery impedance data, and second battery impedance data.

[0188] In the technical solution of this application embodiment, unlike the traditional electrolyte ion transport number test method which only considers the electrolyte impedance as the ohmic impedance of the battery, resulting in inaccurate impedance data, accurate battery impedance data can be obtained by sequentially fitting and correcting the electrochemical impedance spectral data under different states. Furthermore, based on the accurate battery impedance data, current change data, and voltage change data, a more accurate ion transport number can be obtained, thus improving the accuracy of the ion transport number.

[0189] In some embodiments, the data processing module 720 is further configured to perform impedance fitting processing on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data to obtain first initial battery impedance data and second initial battery impedance data, and to perform correction processing on the first initial battery impedance data and the second initial battery impedance data according to a preset correction coefficient to obtain corrected first battery impedance data and second battery impedance data.

[0190] In some embodiments, the first initial battery impedance data includes a first interface impedance and a first ohmic impedance, the second initial battery impedance data includes a second interface impedance and a second ohmic impedance, and the current change data includes an initial current and a steady-state current.

[0191] The data processing module 720 is also used to correct the first ohmic impedance and the second ohmic impedance according to the preset correction coefficient to obtain the first target ohmic impedance and the second target ohmic impedance.

[0192] The ion mobility number determination module 730 is also used to determine the ion mobility number of each test battery pack based on voltage change data, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance, and second target ohmic impedance.

[0193] like Figure 10 As shown, in some embodiments, the device further includes a correction coefficient determination module 712, used to acquire historical test data of the target battery pack, the target battery pack including multiple battery packs with different numbers of separator layers, the historical test data including historical electrochemical impedance spectral data of each battery pack in the open circuit state, fitting the historical electrochemical impedance spectral data to obtain multiple sets of ohmic impedance, linearly fitting the multiple sets of ohmic impedance to obtain linear parameters, and determining a preset correction coefficient based on the linear parameters.

[0194] like Figure 10 As shown, in some embodiments, the device further includes a voltage correction module 722 for correcting the voltage in the voltage change data to obtain the target polarization voltage; the ion migration number determination module 730 is also used to determine the ion migration number of each test battery pack based on the target polarization voltage, initial current, steady-state current, first interface impedance, first target ohmic impedance, second interface impedance and second target ohmic impedance.

[0195] In some embodiments, voltage change data includes open-circuit voltage;

[0196] The voltage correction module 722 is also used to determine the average voltage based on voltage change data, and to obtain the target polarization voltage based on the average voltage and the open-circuit voltage.

[0197] In some embodiments, the second initial battery impedance data also includes the SEI impedance and the second charge transfer impedance;

[0198] like Figure 11 As shown, the device also includes an abnormal data screening module 740, which is used to obtain the voltage difference of each test battery pack based on the target polarization voltage, the second ohmic impedance, the SEI impedance, the second charge transfer impedance and the initial current in the current change data, compare the voltage difference of each test battery pack with a preset voltage difference threshold, screen out abnormal battery packs, which are battery packs with voltage differences less than the preset voltage difference threshold, and remove the test data and ion migration number of abnormal battery packs.

[0199] Each module in the aforementioned electrolyte ion transport number testing device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0200] In some embodiments, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 11 As 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 computing 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 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 method for testing the transport number of electrolyte ions. 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.

[0201] Those skilled in the art will understand that Figure 11The 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.

[0202] In some embodiments, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described electrolyte ion transport number test method.

[0203] In some embodiments, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-described electrolyte ion transport number test method.

[0204] In some embodiments, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described electrolyte ion transport number test method.

[0205] It should be noted that the data involved in this application (including but not limited to data used for analysis, data stored, data displayed, etc.) are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0206] 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.

[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method of testing the ion transport number of an electrolyte, characterized in that, The method comprises: acquiring test data of test battery groups, the test data comprising voltage variation data and current variation data of each test battery group in a constant potential polarization state, and first electrochemical impedance spectrum data in the polarization state and second electrochemical impedance spectrum data in an open circuit state; performing impedance fitting processing on the first electrochemical impedance spectrum data and the second electrochemical impedance spectrum data to obtain first initial battery impedance data and second initial battery impedance data, and performing correction processing on first ohmic impedance in the first initial battery impedance data and second ohmic impedance in the second initial battery impedance data to obtain first battery impedance data and second battery impedance data; determining ion migration numbers of each test battery group according to the voltage variation data, the current variation data, the first battery impedance data and the second battery impedance data.

2. The method of claim 1, wherein, The correction processing on the first ohmic impedance in the first initial battery impedance data and the second ohmic impedance in the second initial battery impedance data comprises: performing correction processing on the first ohmic impedance in the first initial battery impedance data and the second ohmic impedance in the second initial battery impedance data according to a preset correction coefficient to obtain first target ohmic impedance and second target ohmic impedance.

3. The method of claim 2, wherein, The first initial battery impedance data further comprises first interface impedance, and the second initial battery impedance data further comprises second interface impedance, and the current variation data comprises initial current and steady-state current; The determination of the ion migration numbers of each test battery group according to the voltage variation data, the current variation data, the first battery impedance data and the second battery impedance data comprises: determining the ion migration numbers of each test battery group according to the voltage variation data, the initial current, the steady-state current, the first interface impedance, the first target ohmic impedance, the second interface impedance and the second target ohmic impedance.

4. The method of claim 2, wherein, Before the correction processing on the first ohmic impedance in the first initial battery impedance data and the second ohmic impedance in the second initial battery impedance data according to the preset correction coefficient to obtain the first target ohmic impedance and the second target ohmic impedance, the method further comprises: acquiring historical test data of a target battery group, the target battery group comprising multiple battery groups with different numbers of separators, and the historical test data comprising historical electrochemical impedance spectrum data of each battery group in an open circuit state; performing fitting processing on the historical electrochemical impedance spectrum data to obtain multiple ohmic impedances; performing linear fitting on the multiple ohmic impedances to obtain linear parameters; determining the preset correction coefficient according to the linear parameters.

5. The method of claim 3, wherein, Before the determination of the ion migration numbers of each test battery group according to the voltage variation data, the initial current, the steady-state current, the first interface impedance, the first target ohmic impedance, the second interface impedance and the second target ohmic impedance, the method further comprises: correcting voltage in the voltage variation data to obtain target polarization voltage; The determining the ion transference number of each test battery pack according to the voltage change data, the initial current, the steady-state current, the first interface impedance, the first target ohmic impedance, the second interface impedance, and the second target ohmic impedance comprises: The determining the ion transference number of each test battery pack according to the target polarization voltage, the initial current, the steady-state current, the first interface impedance, the first target ohmic impedance, the second interface impedance, and the second target ohmic impedance.

6. The method of claim 5, wherein, The voltage change data comprises an open circuit voltage; The correcting the voltage in the voltage change data to obtain the target polarization voltage comprises: The determining the voltage average value based on the voltage change data; The obtaining the target polarization voltage according to the voltage average value and the open circuit voltage.

7. The method of claim 5, wherein, The second initial battery impedance data further comprises an SEI impedance and a second charge transfer impedance; After the determining the ion transference number of each test battery pack according to the target polarization voltage, the initial current, the steady-state current, the first interface impedance, the first target ohmic impedance, the second interface impedance, and the second target ohmic impedance, the method further comprises: The obtaining the voltage difference of each test battery pack according to the target polarization voltage, the second ohmic impedance, the SEI impedance, the second charge transfer impedance, and the initial current in the current change data; The comparing the voltage difference of each test battery pack with a preset voltage difference threshold value to screen out an abnormal battery pack, the abnormal battery pack being a battery pack with a voltage difference less than the preset voltage difference threshold value; The eliminating the test data and the ion transference number of the abnormal battery pack.

8. An electrolyte ion transport number test system characterized by, The system comprises a test device and a test control device connected with each other; The test control device is configured to implement the ion transference number test of the test device by using the method according to any one of claims 1 to 7, to obtain the ion transference number of the test device.

9. The system of claim 8, wherein, The test device comprises a battery device that cannot be disassembled.

10. The system of claim 9, wherein, The battery device comprises a diaphragm and an insulating adhesive layer with a through hole, the diaphragm is embedded in the through hole, and the difference between the inner diameter and the outer diameter of the insulating adhesive layer is a target value, the target value is used to make the detection area of the battery device be the diaphragm without the coverage of the insulating adhesive layer.

11. The system of any one of claims 8 to 10, wherein, The test control device is further configured to perform electrochemical impedance spectroscopy test on the test device by using a test frequency that is not less than a target cutoff frequency, the target cutoff frequency is used to maintain the steady state of the test device.

12. An electrolyte ion transport number test apparatus characterized by comprising: The device comprises: The data acquisition module is configured to acquire test data of test battery packs, the test data comprising voltage change data and current change data of each test battery pack in a constant potential polarization state, and first electrochemical impedance spectroscopy data in a polarization state and second electrochemical impedance spectroscopy data in an open circuit state; The data processing module is configured to perform impedance fitting processing on the first electrochemical impedance spectroscopy data and the second electrochemical impedance spectroscopy data to obtain first initial battery impedance data and second initial battery impedance data, and perform correction processing on a first ohmic impedance in the first initial battery impedance data and a second ohmic impedance in the second initial battery impedance data to obtain first battery impedance data and second battery impedance data; An ion transference number determination module for determining the ion transference number of each test battery pack from the voltage change data, the current change data, the first battery impedance data and the second battery impedance data.

13. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 7.

14. A computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 7.

15. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 7. The computer program is executed by the processor to implement the steps of the method of any one of claims 1 to 7.

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