Method and device for testing performance of diaphragm and nonvolatile storage medium

Abstract

The invention discloses a diaphragm performance testing method and device and a nonvolatile storage medium. The method comprises the steps that ohmic resistors corresponding to a plurality of symmetrical batteries are obtained, and the number of layers of target diaphragms corresponding to the symmetrical batteries is different; fitting the ohmic resistances corresponding to the plurality of symmetrical batteries, and determining the ion resistance of the target diaphragm; measuring a current peak value of the single-layer target diaphragm symmetrical battery after applying the positive bias voltage for a first preset time period and applying a bias voltage in a direction opposite to the positive bias voltage for a second preset time period; based on the bias voltage in the direction opposite to the positive bias voltage, the current peak value and the ion resistance of the target diaphragm, determining the electronic resistance of the target diaphragm; and determining a performance test result of the target diaphragm based on the electronic resistance of the target diaphragm. According to the invention, the technical problem that the obtained diaphragm performance is not accurate enough due to the fact that the current diaphragm evaluation defaults that the diaphragm is an insulator and only the ionic conductivity is concerned to represent the ionic conduction capability of the diaphragm is solved.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more specifically, to a method and apparatus for testing the performance of a separator and a non-volatile storage medium. Background Technology

[0002] The separator is a crucial component of lithium-ion batteries, serving to wet the electrolyte and isolate the positive and negative electrodes. Its main characteristics are electronic insulation, electrolyte wettability, and appropriately sized pores to facilitate the movement of lithium ions between the electrodes. Although the separator does not directly provide energy to the battery, its physicochemical properties affect the battery's electrical and safety performance. Therefore, testing methods for the physicochemical properties of the separator play a critical role in lithium-ion battery design. Among these, the separator's mechanical properties and heat resistance are essential for the cell's safety performance.

[0003] Currently, the evaluation of separators often focuses only on ionic conductivity to characterize the separator's ion conduction capability, assuming that the separator is an insulator. However, compared to a fresh separator, the separator in the battery cell may suffer from problems such as impurity puncture and pore blockage after undergoing different operating conditions, resulting in reduced insulation and increased self-discharge of the battery cell. At the same time, the difference in insulation between different separators will also lead to differences in the self-discharge level of the battery cell. Currently, the electronic conductivity index of the separator is almost ignored, and there are no relevant testing methods.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This invention provides a method, apparatus, and non-volatile storage medium for testing membrane performance, at least addressing the technical problem that current membrane evaluations assume the membrane is an insulator and focus only on ionic conductivity to characterize the membrane's ion conduction capability, resulting in inaccurate membrane performance data.

[0006] According to one aspect of the present invention, a method for testing the performance of a separator is provided, comprising: acquiring the ohmic resistance corresponding to each of a plurality of symmetrical cells, wherein the number of layers of the target separator corresponding to each of the plurality of symmetrical cells is different; fitting the ohmic resistance corresponding to each of the plurality of symmetrical cells to determine the ionic resistance of the target separator; measuring the peak current of the single-layer target separator symmetrical cell after applying a positive bias voltage for a first preset duration and then applying a bias voltage in the opposite direction to the positive bias voltage for a second preset duration; determining the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the single-layer target separator symmetrical cell, and the ionic resistance of the target separator; and determining the performance test result of the target separator based on the electronic resistance of the target separator.

[0007] Optionally, obtaining the ohmic resistance of each of the multiple symmetrical cells includes: measuring the impedance spectrum of each of the multiple symmetrical cells based on electrochemical impedance spectroscopy; extracting the resistance value in a preset frequency region from the impedance spectrum of each of the multiple symmetrical cells; and determining the ohmic resistance of each of the multiple symmetrical cells based on the resistance value in the preset frequency region of each of the multiple symmetrical cells.

[0008] Optionally, the ion resistance of the target membrane is determined by fitting the ohmic resistance of each of the multiple symmetrical cells, including: performing linear fitting based on the ohmic resistance of each of the multiple symmetrical cells and the number of membrane layers of each of the multiple symmetrical cells to obtain a target fitting line; and determining the ion resistance of the target membrane based on the slope of the target fitting line.

[0009] Optionally, the electronic resistance of the target separator is determined based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the symmetrical cell with a single-layer target separator, and the ion resistance of the target separator. This includes: calculating the electronic resistance of the target separator based on a preset formula, according to the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the symmetrical cell with a single-layer target separator, and the ion resistance of the target separator. The preset formula is as follows:

[0010] ,

[0011] in, The electronic resistance of the target diaphragm. A bias voltage in the opposite direction to the positive bias voltage. This is the peak current. The ion resistance of the target membrane.

[0012] Optionally, determining the performance test results of the target diaphragm based on its electronic resistance includes: acquiring parameters of the target diaphragm, wherein the parameters include diaphragm thickness and diaphragm area; determining the electronic conductivity of the target diaphragm based on its parameters and electronic resistance; and determining the performance test results of the target diaphragm based on its electronic resistance and electronic conductivity.

[0013] Optionally, the battery types corresponding to the multiple symmetrical batteries are any of the following: button cells, molded cells, and pouch cells.

[0014] According to another aspect of the present invention, a testing apparatus for membrane performance is also provided, comprising: an acquisition module for acquiring the ohmic resistance corresponding to each of a plurality of symmetrical cells, wherein the number of layers of the target membrane corresponding to each of the plurality of symmetrical cells is different; a first determination module for fitting the ohmic resistance corresponding to each of the plurality of symmetrical cells to determine the ionic resistance of the target membrane; a measurement module for measuring the peak current of a single-layer target membrane symmetrical cell after applying a positive bias voltage for a first preset duration and then applying a bias voltage in the opposite direction to the positive bias voltage for a second preset duration; a second determination module for determining the electronic resistance of the target membrane based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the single-layer target membrane symmetrical cell, and the ionic resistance of the target membrane; and a third determination module for determining the performance test result of the target membrane based on the electronic resistance of the target membrane.

[0015] According to another aspect of the present invention, a non-volatile storage medium is also provided, the non-volatile storage medium including a stored program, wherein, when the program is running, the device where the non-volatile storage medium is located is controlled to perform any of the above-described methods for testing diaphragm performance.

[0016] According to another aspect of the present invention, a computer device is also provided, the computer device including a processor, the processor being configured to run a program, wherein the program, when running, executes any of the above-described methods for testing diaphragm performance.

[0017] According to another aspect of the present invention, a computer program product is also provided, including a computer program that, when executed by a processor, implements a test method for any of the above-described diaphragm performances.

[0018] In this embodiment of the invention, a method for testing membrane performance is employed. This involves acquiring the ohmic resistance of multiple symmetrical cells, each with a different number of layers in the target membrane. The ohmic resistance of the target membrane is determined by fitting the resistances of the multiple symmetrical cells. The peak current of the single-layer target membrane symmetrical cell is measured after applying a first preset duration of forward bias followed by a second preset duration of bias in the opposite direction. Based on the bias in the opposite direction, the peak current of the single-layer target membrane symmetrical cell, and the ionic resistance of the target membrane, the electronic resistance of the target membrane is determined. Based on the electronic resistance of the target membrane, the performance test result of the target membrane is determined. This method achieves accurate membrane performance testing, thereby improving the accuracy of membrane testing. It also solves the current technical problem that membrane evaluation assumes the membrane is an insulator and only focuses on ionic conductivity to characterize the membrane's ion conduction capability, resulting in inaccurate membrane performance data. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0020] Figure 1 A hardware block diagram of a computer terminal for implementing a test method for diaphragm performance is shown.

[0021] Figure 2 This is a schematic flowchart of a method for testing the performance of a diaphragm according to an embodiment of the present invention;

[0022] Figure 3 This is a structural block diagram of a diaphragm performance testing device provided according to an embodiment of the present invention. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] According to an embodiment of the present invention, a method embodiment for testing diaphragm performance is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0026] The method embodiment provided in Embodiment 1 of this application can be executed on a mobile terminal, computer terminal, or similar computing device. Figure 1A hardware block diagram of a computer terminal for implementing a method for testing diaphragm performance is shown. Figure 1 As shown, the computer terminal 10 may include one or more processors (shown as 102a, 102b, ..., 102n in the figure) (the processor may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned electronic device. For example, computer terminal 10 may also include... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0027] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the computer terminal 10. As involved in the embodiments of this application, the data processing circuits serve as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0028] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the diaphragm performance testing method in this embodiment of the invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, thereby realizing the aforementioned application's diaphragm performance testing method. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor, and these remote memories can be connected to the computer terminal 10 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0029] The display can be, for example, a touchscreen liquid crystal display (LCD) that allows the user to interact with the user interface of the computer terminal 10.

[0030] Figure 2This is a schematic flowchart of a method for testing the performance of a diaphragm according to an embodiment of the present invention, as shown below. Figure 2 As shown, the method includes the following steps:

[0031] Step S202: Obtain the ohmic resistance of each of the multiple symmetrical cells, wherein the number of layers of the target separator corresponding to each of the multiple symmetrical cells is different.

[0032] Optionally, the main purpose of obtaining the ohmic resistance of symmetrical cells with different numbers of layers is to establish the relationship between the ohmic resistance of the symmetrical cell and the number of separator layers, and then to deduce the ion resistance characteristics of a single-layer separator. By testing the ohmic resistance of a symmetrical cell assembled with multiple separators and using the number of layers to establish a linear model, the ion resistance of a single-layer separator can be deduced. It can be understood that the ohmic resistance of the symmetrical cell is the dependent variable, and it increases linearly with the increase of the independent variable, the number of separator layers.

[0033] Specifically, a series of symmetrical cells can be prepared, each using the same type of separator, but with a different number of separator layers. For example, a set of cells can be prepared using 1, 2, 3, or 4 layers of separator, etc. Stainless steel gaskets are used as blocking electrodes. These gaskets do not participate in the electrochemical reaction; they are only used to support the separator and form a closed cell structure. An appropriate amount of electrolyte is added to the symmetrical cells, and the assembly conditions of all cells are kept as consistent as possible to reduce unsystematic errors in the experiment. Electrochemical impedance spectroscopy (EIS) is performed on each assembled symmetrical cell. EIS is a commonly used electrochemical testing method that can be used to study the dynamic impedance characteristics inside the cell, including the ion transport impedance of the separator. During measurement, a small AC voltage can be applied, covering a frequency range from low to high frequencies, and the impedance data of the cell at different frequencies is recorded. Based on the EIS measurement results, the ohmic resistance value of each cell is calculated. Ohmic resistance mainly refers to the resistance observed at high frequencies, which reflects the DC resistance characteristics inside the cell, and is usually the resistance value at the intersection of the EIS curve and the real axis. The ohmic resistance values ​​of each battery are linearly fitted to the number of layers in their corresponding separators. Theoretically, the more separator layers there are, the greater the total ohmic resistance. This linear relationship allows the calculation of the ion resistance of a single-layer separator. The slope of the fitted line represents the ion resistance of a single-layer separator. This means that by changing the number of separator layers, the ion resistance characteristics of different separator materials or the same separator under different conditions can be accurately measured and compared.

[0034] Step S204: Fit the ohmic resistance of each of the multiple symmetrical cells to determine the ionic resistance of the target membrane.

[0035] Optionally, based on the ohmic resistance of each of the multiple symmetrical cells, and since the number of separators in each cell is different, the ion resistance of a single-layer separator in each cell, i.e., the ion resistance of the target separator, can be determined using statistical methods. The ion resistance of the target separator is a key parameter for measuring its electrolyte ion transport capability. By testing multiple symmetrical cells, more comprehensive and reliable data can be obtained, thereby accurately quantifying the ion conduction performance of the target separator.

[0036] Specifically, as mentioned earlier, ohmic resistance values ​​of symmetrical cells with different numbers of membrane layers were collected through EIS testing, yielding a series of data points. Statistical methods or graphical software can be used to plot the collected membrane layer number and corresponding ohmic resistance values ​​in a graph. Typically, a linear relationship exists between these two parameters. Based on the data points in the graph, linear regression or other appropriate mathematical modeling methods are used to fit the data and establish a model of the relationship between the ohmic resistance of a symmetrical cell and the number of layers. Theoretically, the ionic resistance of a single-layer membrane can be directly solved from the model.

[0037] Step S206: Measure the peak current of the single-layer target membrane symmetrical cell after applying a first preset duration of positive bias and then applying a second preset duration of bias in the opposite direction to the positive bias.

[0038] Optionally, the peak current of a single-layer target membrane symmetrical cell is measured after a first preset duration of positive bias and a second preset duration of opposite bias. The main purpose is to evaluate the ion and electron transport characteristics of the membrane under an electric field. Based on the dynamic response during charge reversal, the stability of the membrane material, ion conduction efficiency, and the interaction between the electrolyte and the membrane can be revealed. Measuring the peak current helps to understand the instantaneous conductivity change of the membrane during charge reversal. By analyzing the peak current, ion current and electron current can be distinguished, thereby calculating the electronic conductivity and ionic conductivity of the membrane separately.

[0039] Specifically, using an electrochemical workstation (such as Biologic or Gamry equipment), a positive bias voltage (U0) is applied to the symmetrical cell and kept stable for a first preset duration (e.g., 5–120 minutes). During the application of the positive bias voltage, the current changes of the cell are continuously recorded, which helps to observe the process of charge accumulation in the separator. After the first preset duration, a bias voltage (U) in the opposite direction to the positive bias voltage is rapidly applied and kept stable for a second preset duration. At the instant the opposite bias voltage is applied, the peak current (I0) is recorded. This is because under a positive bias voltage, lithium ions in the separator accumulate towards the negative potential side and stabilize there; however, when the bias direction is reversed, the ions in the separator move rapidly in the opposite direction, accompanied by the rapid movement of electrons, resulting in a sudden surge in current. Applying a positive bias voltage and then a subsequent reverse bias voltage allows for precise acquisition of the ion current, thus separating the electronic current from the peak current, and allowing the electronic resistance of the separator to be calculated from the electronic current.

[0040] Step S208: Determine the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the single-layer target separator symmetrical cell, and the ion resistance of the target separator.

[0041] Optionally, by calculating the electronic resistance, we can distinguish the conductive paths of electrons and ions in the separator, better understand the electrical insulation properties of the separator material, and improve the safety and stability of the battery. The electronic resistance reflects the separator's ability to prevent electrons from passing through directly. Low electronic resistance means poor insulation of the separator, which may lead to battery short circuits or accelerated self-discharge.

[0042] Specifically, after applying a positive bias voltage for a first preset duration, the system quickly switches to a negative bias voltage for a second preset duration, and records the current value (I0) when the first peak value is reached. The ion resistance (R0) of the target membrane was also obtained through previous experiments or tests. ion Data. Utilizing the measured peak current (I0), applied bias voltage (U), and ion resistance (R) of the target membrane. ion The electronic resistance of the target membrane is calculated according to a predetermined formula.

[0043] Step S210: Determine the performance test results of the target membrane based on the electronic resistance of the target membrane.

[0044] Optionally, electronic resistance is a quantitative indicator of a separator's ability to prevent electrons from passing directly through. Low electronic resistance may indicate poor separator insulation, which directly affects battery safety and stability. By comparing the electronic resistance of different separators, their suitability for battery design can be evaluated, allowing for the selection of the separator material that best meets performance requirements. Understanding the electronic resistance of a target separator helps optimize battery structure design, such as adjusting separator thickness, number of layers, or selecting the optimal electrolyte, to improve overall battery performance.

[0045] Specifically, based on pre-measured and calculated data, including electronic resistance (R... e The parameters include membrane thickness (d), membrane area (S), etc. Using the electronic resistance value, combined with the membrane thickness and area, the electronic conductivity (σ) of the target membrane is calculated. e Electronic conductivity reflects the ability of a diaphragm to conduct electricity per unit area and unit thickness, and is another important indicator for measuring the insulation performance of a diaphragm. Analyzing the electronic resistance and electronic conductivity of a target diaphragm and comparing it with the performance of a standard diaphragm or performance target allows for an assessment of whether the target diaphragm meets the electronic insulation requirements. Furthermore, the data on electronic resistance and conductivity can be combined with other performance indicators of the diaphragm (such as ionic conductivity, mechanical strength, heat resistance, etc.) to comprehensively evaluate the overall performance of the diaphragm.

[0046] Through the above steps, the goal of accurately testing the membrane performance is achieved, thereby improving the technical effect of membrane testing accuracy. This solves the technical problem that current membrane evaluation often only focuses on ionic conductivity to characterize the membrane's ion conduction capability, assuming the membrane is an insulator, which leads to the inaccurate measurement of the membrane's electronic resistance.

[0047] As an optional embodiment, this can be achieved through the following steps: obtaining the ohmic resistance of each of the multiple symmetrical cells, including: measuring the impedance spectrum of each of the multiple symmetrical cells based on electrochemical impedance spectroscopy; extracting the resistance value in a preset frequency region from the impedance spectrum of each of the multiple symmetrical cells; and determining the ohmic resistance of each of the multiple symmetrical cells based on the resistance value in the preset frequency region of each of the multiple symmetrical cells.

[0048] Optionally, the ion resistance of the separator is an important indicator of separator quality, as it directly affects the ion conduction performance of the battery. Electrochemical impedance spectroscopy (EIS) testing can accurately extract ohmic resistance values ​​from high-frequency impedance spectra, providing a basis for the screening and optimization of separator materials.

[0049] Specifically, following standardized procedures, multiple symmetrical cells are assembled using the target membrane material and other consistent components. Electrochemical indexing (EIS) testing is performed using an electrochemical workstation, applying small-amplitude AC voltages (typically between a few millivolts and tens of millivolts) and collecting impedance data over a wide frequency range (from hundreds of kilohertz to a few millihertz). From the collected impedance spectra, the focus is on analyzing data in the high-frequency region (generally above 1 kHz), as the impedance in the high-frequency range primarily reflects the ionic resistance characteristics of the membrane. In the high-frequency region of the impedance spectrum, the impedance value tends towards purely resistive behavior; the recorded impedance value (|Z|) at this point represents the ohmic resistance of the symmetrical cell, primarily consisting of the membrane ionic resistance (R0). ion The data includes system resistances (such as contact resistance between components). For each symmetrical cell, the EIS test and data extraction steps described above are repeated to ensure data reliability and consistency. By changing the number of separator layers or using separators made of different materials, the EIS test is performed again. Using the number of separator layers as a single variable, the ohmic resistance of the symmetrical cell is linearly fitted to the number of separator layers to obtain an accurate separator ion resistance. Based on the above steps, the ion resistance of the separator can be accurately measured.

[0050] As an optional embodiment, this can be achieved through the following steps: fitting the ohmic resistance of each of the multiple symmetrical cells to determine the ion resistance of the target separator, including: performing linear fitting based on the ohmic resistance of each of the multiple symmetrical cells and the number of separator layers of each of the multiple symmetrical cells to obtain a target fitting line; and determining the ion resistance of the target separator based on the slope of the target fitting line.

[0051] Optionally, the ionic resistance of the target separator can be determined based on the ohmic resistance of each of the multiple symmetrical cells. This typically involves statistical analysis and linear fitting of the data, which can identify the changing trend of the ohmic resistance of the symmetrical cells under different numbers of layers, and then calculate the ionic resistance of a single-layer separator.

[0052] Specifically, based on the ohmic resistance (R) of the symmetrical battery and the number of separator layers (N) used in each symmetrical battery, the collected ohmic resistance (R) and separator layer number (N) data were organized into a table. Each row represents the test results of one symmetrical battery, containing two columns of data: R and N. Statistical software or mathematical tools (such as Excel, Python's SciPy library, MATLAB, etc.) were used to perform a linear fit on the relationship between the battery ohmic resistance (R) and the number of separator layers (N). The objective function was set as R = a N + b, where a and b are fitting parameters, representing the slope and intercept of the line, respectively. Given a prepared dataset, perform least squares or other appropriate fitting algorithms to find the optimal values ​​of a and b that minimize the sum of the squared distances from all points to the fitted line. Check that the correlation coefficient of the linear fit is close to 1 to ensure the accuracy of the fit. The slope 'a' of the fitted line is the desired membrane ion resistance R. ion .

[0053] As an optional embodiment, this can be achieved through the following steps: determining the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator, including: calculating the electronic resistance of the target separator based on a preset formula, according to the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator, wherein the preset formula is as follows:

[0054]

[0055] in, The electronic resistance of the target diaphragm. A bias voltage in the opposite direction to the positive bias voltage. This is the peak current. The ion resistance of the target membrane.

[0056] Alternatively, in a battery, the primary function of the separator is to allow ions to pass through while blocking the direct flow of electrons. Therefore, distinguishing between electron current and ion current is crucial for understanding the insulating performance of the separator. When a bias voltage is applied in opposite directions, the initial current peak includes contributions from both electrons and ions, and these two components can be separated through formula calculations.

[0057] Specifically, a positive bias voltage is applied to stabilize the battery for a period of time, then the bias voltage is quickly switched to the opposite direction (U) until the current reaches the first peak value (I0). The ion resistance (R) of the target separator is measured based on the steps described above. ion ) Apply the formula to calculate The principle behind the formula is that when the current reverses, the peak current (I0) is composed of both the electron current and the ion current passing through the separator. When the battery suddenly switches from a forward bias to a reverse bias, the ion resistance (R) of the separator... ion ) allows a certain amount of ionic current to pass through, while the electronic resistance (R) e The peak current (I0) and the known ionic resistance (R) determine the electron's ability to pass through. This formula is derived from the measured peak current (I0) and the known ionic resistance (R). ion Solve for the electronic resistance (R) e ).

[0058] As an optional embodiment, this can be achieved through the following steps: determining the performance test results of the target diaphragm based on its electronic resistance, including: acquiring parameters of the target diaphragm, wherein the parameters include diaphragm thickness and diaphragm area; determining the electronic conductivity of the target diaphragm based on its parameters and electronic resistance; and determining the performance test results of the target diaphragm based on its electronic resistance and electronic conductivity.

[0059] Optionally, based on the electronic resistance (R) of the target membrane e To evaluate its performance, it is necessary to calculate the electronic conductivity (σ). e This process involves comprehensively evaluating the separator's performance in the battery. It considers not only the separator's electronic insulation capabilities but also its physical properties, such as thickness (d) and area (S), enabling accurate assessment of the target separator's performance.

[0060] Specifically, a precision thickness measuring instrument, such as a digital micrometer, can be used to measure the thickness of the target separator. To ensure the representativeness of the measurement points, multiple measurements can be taken at different locations on the separator, and then the average value is calculated. The effective area of ​​the target separator within the battery is measured or determined, typically referring to the area of ​​contact between the separator and the electrodes. This is based on the known electronic resistance (R0). e The electronic conductivity (σ) is calculated using the following formula, taking into account the membrane thickness (d) and membrane area (S). e ): σ e =d / (R e (×S), where electronic conductivity is the ability of a separator material to conduct electricity per unit thickness and unit area. Low conductivity indicates high insulation. Analyzing the electronic resistance values ​​of the target separator compared to other separator materials assesses its insulation performance. The level of electronic conductivity reflects the separator's efficiency in preventing electron flow; low conductivity is a key indicator of high-quality separator materials. Combining existing separator performance indicators (such as ionic conductivity, mechanical strength, and heat resistance) with newly obtained electronic resistance and conductivity, a comprehensive evaluation of the target separator's overall performance is conducted. Electronic resistance and conductivity are directly related to the separator's electronic insulation performance; high electronic resistance and low electronic conductivity indicate that the separator effectively prevents internal short circuits in the battery. The separator's electronic insulation performance affects the battery's self-discharge rate, and consequently, its energy efficiency. Higher electronic resistance indicates better separator insulation and a lower self-discharge rate.

[0061] As an optional embodiment, the battery types corresponding to the multiple symmetrical batteries are any of the following: button cells, molded cells, and pouch cells.

[0062] Alternatively, a coin cell is a round, flat battery design, similar to a common coin cell. It typically consists of two metal caps (serving as electrodes) and a separator and electrolyte in the middle. Coin cells are small, easy to handle, have good test repeatability, and are easy to test electrochemical performance in a laboratory environment. Mold batteries (such as Swagelok batteries) have a similar structure to coin cells, but with different configurations. They consist of two terminals, an insulating shell, and a sealing structure. Assembly is simple, and they are often customized for different testing equipment. Pouch batteries are batteries with flexible encapsulation, typically encapsulated in an aluminum-plastic composite film. They contain electrodes, a separator, and electrolyte. Mold batteries offer high energy density and flexibility, adapting to different shapes and sizes, and are suitable for in-depth performance testing of separator materials. The choice between coin cells, mold batteries, and pouch batteries as the type of symmetrical battery depends primarily on the detailed testing requirements and the performance indicators of interest.

[0063] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0064] Through the above description of the embodiments, those skilled in the art can clearly understand that the diaphragm performance testing method according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0065] According to embodiments of the present invention, a testing apparatus for diaphragm performance is also provided for implementing the above-described testing method for diaphragm performance. Figure 3 This is a structural block diagram of a diaphragm performance testing device provided according to an embodiment of the present invention, as shown below. Figure 3 As shown, the diaphragm performance testing device includes: an acquisition module 302, a first determination module 304, a measurement module 306, a second determination module 308, and a third determination module 310. The diaphragm performance testing device will be described below.

[0066] The acquisition module 302 is used to acquire the ohmic resistance of each of the multiple symmetrical cells, wherein the number of layers of the target separator corresponding to each of the multiple symmetrical cells is different.

[0067] The first determining module 304, connected to the acquiring module 302, is used to fit the ohmic resistance of each of the multiple symmetrical cells to determine the ion resistance of the target membrane.

[0068] The measurement module 306, connected to the first determination module 304, is used to measure the peak current of a single-layer target membrane symmetrical battery after a first preset duration of positive bias is applied and a second preset duration of bias in the opposite direction is applied.

[0069] The second determining module 308, connected to the measuring module 306, is used to determine the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the current peak value corresponding to the single-layer target separator symmetrical cell, and the ion resistance of the target separator.

[0070] The third determining module 310, connected to the second determining module 308, is used to determine the performance test results of the target diaphragm based on the electronic resistance of the target diaphragm.

[0071] It should be noted that the acquisition module 302, the first determination module 304, the measurement module 306, the second determination module 308, and the third determination module 310 mentioned above correspond to steps S202 to S210 in the embodiments. Multiple modules and their corresponding steps implement the same instances and application scenarios, but are not limited to the content disclosed in the above embodiments. It should also be noted that the above modules, as part of the device, can run on the computer terminal 10 provided in the embodiments.

[0072] Embodiments of the present invention may provide a computer device. Optionally, in this embodiment, the computer device may be located in at least one of a plurality of network devices in a computer network. The computer device includes a memory and a processor.

[0073] The memory can be used to store software programs and modules, such as the program instructions / modules corresponding to the diaphragm performance testing method and apparatus in this embodiment of the invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, thereby realizing the aforementioned diaphragm performance testing method. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to a computer terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0074] The processor can access information and applications stored in the memory via a transmission device to perform the following steps: acquiring the ohmic resistances of multiple symmetrical cells, wherein the target separators corresponding to the multiple symmetrical cells have different numbers of layers; fitting the ohmic resistances of the multiple symmetrical cells to determine the ionic resistance of the target separator; measuring the peak current of the single-layer target separator symmetrical cell after applying a positive bias for a first preset duration followed by a bias in the opposite direction for a second preset duration; determining the electronic resistance of the target separator based on the bias in the opposite direction, the peak current of the single-layer target separator symmetrical cell, and the ionic resistance of the target separator; and determining the performance test results of the target separator based on the electronic resistance of the target separator.

[0075] Optionally, the processor may also execute program code for the following steps: obtaining the ohmic resistance of each of the multiple symmetrical cells, including: measuring the impedance spectrum of each of the multiple symmetrical cells based on electrochemical impedance spectroscopy; extracting the resistance value in a preset frequency region from the impedance spectrum of each of the multiple symmetrical cells; and determining the ohmic resistance of each of the multiple symmetrical cells based on the resistance value in the preset frequency region of each of the multiple symmetrical cells.

[0076] Optionally, the processor may also execute program code for the following steps: fitting the ohmic resistance of each of the multiple symmetrical cells to determine the ion resistance of the target membrane, including: performing linear fitting based on the ohmic resistance of each of the multiple symmetrical cells and the number of membrane layers of each of the multiple symmetrical cells to obtain a target fitting line; and determining the ion resistance of the target membrane based on the slope of the target fitting line.

[0077] Optionally, the processor may also execute program code for the following steps: determining the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator, including: calculating the electronic resistance of the target separator based on a preset formula, according to the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator, wherein the preset formula is as follows:

[0078] ,

[0079] in, The electronic resistance of the target diaphragm. A bias voltage in the opposite direction to the positive bias voltage. This is the peak current. The ion resistance of the target membrane.

[0080] Optionally, the processor may also execute program code for the following steps: determining the performance test results of the target diaphragm based on its electronic resistance, including: acquiring parameters of the target diaphragm, wherein the parameters include diaphragm thickness and diaphragm area; determining the electronic conductivity of the target diaphragm based on its parameters and electronic resistance; and determining the performance test results of the target diaphragm based on its electronic resistance and electronic conductivity.

[0081] Optionally, the processor may also execute program code for the following steps: the battery types corresponding to the multiple symmetrical batteries are any of the following: button cells, mold cells, and pouch cells.

[0082] This invention provides a method for testing the performance of a separator. The method involves acquiring the ohmic resistance of multiple symmetrical cells, each with a different number of layers in the target separator; fitting the ohmic resistance of the multiple symmetrical cells to determine the ionic resistance of the target separator; measuring the peak current of a single-layer target separator symmetrical cell after applying a first preset duration of forward bias followed by a second preset duration of bias in the opposite direction; determining the electronic resistance of the target separator based on the bias in the opposite direction, the peak current of the single-layer target separator symmetrical cell, and the ionic resistance of the target separator; and determining the performance test result of the target separator based on its electronic resistance. This method achieves accurate testing of separator performance, thereby improving the accuracy of separator testing and solving the problem that current separator evaluations assume the separator is an insulator and only focus on ionic conductivity to characterize the separator's ion conduction capability, resulting in inaccurate separator performance data.

[0083] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing the hardware related to the terminal device. The program can be stored in a non-volatile storage medium, which may include: flash drive, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0084] Embodiments of the present invention also provide a non-volatile storage medium. Optionally, in this embodiment, the non-volatile storage medium can be used to store the program code executed by the test method for diaphragm performance provided in the above embodiments.

[0085] Optionally, in this embodiment, the non-volatile storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any mobile terminal in a group of mobile terminals.

[0086] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: obtaining the ohmic resistance corresponding to each of the multiple symmetrical cells, wherein the number of layers of the target separator corresponding to each of the multiple symmetrical cells is different; fitting the ohmic resistance corresponding to each of the multiple symmetrical cells to determine the ionic resistance of the target separator; measuring the peak current of the single-layer target separator symmetrical cell after applying a positive bias voltage for a first preset duration and then applying a bias voltage in the opposite direction for a second preset duration; determining the electronic resistance of the target separator based on the bias voltage in the opposite direction, the peak current corresponding to the single-layer target separator symmetrical cell, and the ionic resistance of the target separator; and determining the performance test result of the target separator based on the electronic resistance of the target separator.

[0087] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: obtaining the ohmic resistance of each of the multiple symmetrical cells, including: measuring the impedance spectrum of each of the multiple symmetrical cells based on electrochemical impedance spectroscopy; extracting the resistance value in a preset frequency region from the impedance spectrum of each of the multiple symmetrical cells; and determining the ohmic resistance of each of the multiple symmetrical cells based on the resistance value in the preset frequency region of each of the multiple symmetrical cells.

[0088] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: fitting the ohmic resistance of each of the multiple symmetrical cells to determine the ion resistance of the target separator, including: performing linear fitting based on the ohmic resistance of each of the multiple symmetrical cells and the number of separator layers of each of the multiple symmetrical cells to obtain a target fitting line; and determining the ion resistance of the target separator based on the slope of the target fitting line.

[0089] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: determining the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator, including: calculating the electronic resistance of the target separator based on a preset formula, according to the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator, wherein the preset formula is as follows:

[0090] ,

[0091] in, The electronic resistance of the target diaphragm. A bias voltage in the opposite direction to the positive bias voltage. This is the peak current. The ion resistance of the target membrane.

[0092] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: determining the performance test results of the target diaphragm based on its electronic resistance, including: acquiring parameters of the target diaphragm, wherein the parameters include diaphragm thickness and diaphragm area; determining the electronic conductivity of the target diaphragm based on its parameters and electronic resistance; and determining the performance test results of the target diaphragm based on its electronic resistance and electronic conductivity.

[0093] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: the battery types corresponding to the plurality of symmetrical batteries are any of the following: button cells, mold cells, and pouch cells.

[0094] Embodiments of the present invention also provide a computer program product, including a computer program. Optionally, in this embodiment, when the computer program is executed by a processor, it can: acquire the ohmic resistance corresponding to each of a plurality of symmetrical cells, wherein the number of layers of the target separator corresponding to each of the plurality of symmetrical cells is different; fit the ohmic resistance corresponding to each of the plurality of symmetrical cells to determine the ionic resistance of the target separator; measure the peak current of the single-layer target separator symmetrical cell after applying a positive bias voltage for a first preset duration and then applying a bias voltage in the opposite direction for a second preset duration; determine the electronic resistance of the target separator based on the bias voltage in the opposite direction, the peak current corresponding to the single-layer target separator symmetrical cell, and the ionic resistance of the target separator; and determine the performance test result of the target separator based on the electronic resistance of the target separator.

[0095] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0096] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0097] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0098] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0099] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0100] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a non-volatile storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for testing the performance of a diaphragm, characterized in that, include: Obtain the ohmic resistance of each of the multiple symmetrical cells, wherein the number of layers of the target separator corresponding to each of the multiple symmetrical cells is different; The ionic resistance of the target membrane is determined by fitting the ohmic resistance of each of the plurality of symmetrical cells. The peak current of a single-layer target membrane symmetrical cell is measured after a first preset duration of positive bias is applied and a second preset duration of bias in the opposite direction is applied. The electronic resistance of the target membrane is determined based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the single-layer target membrane symmetrical cell, and the ion resistance of the target membrane. The performance test results of the target membrane are determined based on its electronic resistance.

2. The method according to claim 1, characterized in that, The process of obtaining the ohmic resistance of each of the multiple symmetrical cells includes: The impedance spectra of the various symmetrical cells were measured based on electrochemical impedance spectroscopy. The resistance values ​​within a preset frequency range are extracted from the impedance spectra corresponding to each of the plurality of symmetrical cells; Based on the resistance values ​​within the preset frequency range corresponding to each of the plurality of symmetrical cells, the ohmic resistance of each of the plurality of symmetrical cells is determined.

3. The method according to claim 1, characterized in that, The step of fitting the ohmic resistance of each of the plurality of symmetrical cells to determine the ionic resistance of the target separator includes: Based on the ohmic resistance of each of the plurality of symmetrical cells and the number of membrane layers of each of the plurality of symmetrical cells, a linear fit is performed to obtain the target fitting line; The ion resistance of the target membrane is determined based on the slope of the target fitted line.

4. The method according to claim 1, characterized in that, The determination of the electronic resistance of the target separator based on the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the monolayer target separator symmetrical cell, and the ion resistance of the target separator includes: Based on a preset formula, the electronic resistance of the target membrane is calculated according to the bias voltage in the opposite direction to the positive bias voltage, the peak current corresponding to the single-layer target membrane symmetrical cell, and the ion resistance of the target membrane. The preset formula is as follows: ， in, The electronic resistance of the target membrane. The bias voltage is in the opposite direction to the positive bias voltage. The peak current is... The ion resistance of the target membrane.

5. The method according to claim 1, characterized in that, The determination of the performance test results of the target membrane based on its electronic resistance includes: Obtain the parameters of the target membrane, wherein the parameters include membrane thickness and membrane area; The electronic conductivity of the target membrane is determined based on the parameters of the target membrane and the electronic resistance of the target membrane. The performance test results of the target membrane are determined based on the electronic resistance and electronic conductivity of the target membrane.

6. The method according to any one of claims 1 to 5, characterized in that, The battery types corresponding to the plurality of symmetrical batteries are any of the following: button cells, mold cells, and pouch cells.

7. A testing device for diaphragm performance, characterized in that, include: An acquisition module is used to acquire the ohmic resistance of each of the multiple symmetrical cells, wherein the number of layers of the target separator corresponding to each of the multiple symmetrical cells is different; The first determining module is used to fit the ohmic resistance corresponding to each of the plurality of symmetrical cells to determine the ion resistance of the target membrane. The measurement module is used to measure the peak current of a single-layer target membrane symmetrical battery after a first preset duration of applying a positive bias voltage and a second preset duration of applying a bias voltage in the opposite direction to the positive bias voltage. The second determining module is used to determine the electronic resistance of the target membrane based on the bias voltage in the opposite direction to the positive bias voltage, the current peak value corresponding to the single-layer target membrane symmetrical cell, and the ion resistance of the target membrane. The third determining module is used to determine the performance test results of the target diaphragm based on the electronic resistance of the target diaphragm.

8. A non-volatile storage medium, characterized in that, The non-volatile storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the non-volatile storage medium to perform the test method for the diaphragm performance of any one of claims 1 to 6.

9. A computer device, characterized in that, include: Memory and processor The memory stores computer programs; The processor is configured to execute a computer program stored in the memory, wherein when the computer program is executed, the processor performs the test method for the diaphragm performance according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the test method for the diaphragm performance according to any one of claims 1 to 6.

Images