Lithium ion battery infiltration state detection method and device, medium and computer program product

Abstract

The invention relates to a method for detecting the infiltration state of a lithium ion battery, which comprises the following steps of: performing in-situ electrochemical impedance spectroscopy test on the lithium ion battery in a liquid injection infiltration process to obtain impedance spectroscopy data changing along with infiltration time; performing fitting processing on the impedance spectrum data by using a preset equivalent circuit model; wherein the equivalent circuit model comprises a transmission line model element used for representing the impedance characteristic of the porous electrode; extracting a capacitance value corresponding to the transmission line model element from the fitting result; determining the infiltration state of the lithium ion battery according to the variation trend of the capacitance value along with the infiltration time; wherein the increasing rate of the capacitance value is positively correlated with the infiltration rate of the electrolyte in the lithium ion battery. The invention also relates to equipment for detecting the infiltration state of the lithium ion battery, a medium and a computer program product.

Description

Technical Field

[0001] This invention relates to the field of computer technology, and in particular to methods, equipment, media, and computer program products for detecting the immersion state of lithium-ion batteries. Background Technology

[0002] The performance of lithium-ion batteries (such as cycle life, rate performance, and safety) is highly dependent on the sufficient wetting of the electrolyte in the pores of the electrodes and separator. Insufficient wetting can lead to increased interfacial impedance, lithium plating, and poor SEI film formation. Currently, the industry mainly relies on empirical parameters such as settling time and temperature to control the wetting process, or uses weighing methods, infrared thermal imaging, and X-ray / CT detection methods. However, weighing methods can only reflect the overall amount of electrolyte absorbed and cannot identify localized wetting blind spots inside the cell (such as the middle or dead corners of the electrodes); infrared imaging technology is greatly affected by environmental noise and usually requires thermal excitation; X-ray / CT and other imaging technologies are expensive and time-consuming, making it difficult to meet the online full inspection requirements of large-scale production lines. Overall, existing technologies generally suffer from problems such as indirect detection methods, lack of quantitative analysis capabilities, inability to achieve in-situ real-time monitoring, and difficulty in providing feedback to guide process optimization. This often leads to the need for "over-design" methods that extend the settling time in production, thereby reducing production efficiency and making it difficult to ensure product consistency. Summary of the Invention

[0003] The purpose of this invention is to provide a method, device, medium, and computer program product for detecting the wetting state of lithium-ion batteries, thereby solving the technical problems of existing lithium-ion battery wetting detection methods, such as limited detection dimensions, lack of quantitative and real-time assessment capabilities of internal wetting state, low detection efficiency, high cost, and inability to effectively support closed-loop control of the wetting process.

[0004] The first embodiment of the present invention discloses a method for detecting the wetting state of a lithium-ion battery, comprising:

[0005] In-situ electrochemical impedance spectroscopy was performed on lithium-ion batteries during the liquid injection process to obtain impedance spectral data as a function of the injection time.

[0006] The impedance spectrum data is fitted using a preset equivalent circuit model; wherein, the equivalent circuit model includes transmission line model elements for characterizing the impedance characteristics of the porous electrode.

[0007] Extract the capacitance values ​​corresponding to the transmission line model elements from the fitting results;

[0008] The immersion state of the lithium-ion battery is determined based on the trend of the capacitance value changing with immersion time; wherein the rate of increase of the capacitance value is positively correlated with the immersion rate of the electrolyte inside the lithium-ion battery.

[0009] According to the method of the first embodiment of the present invention, determining the immersion state of the lithium-ion battery based on the trend of the capacitance value changing with immersion time includes:

[0010] Monitor the rate of change of the capacitance value over time;

[0011] When the rate of change is positive and the value is within the first preset range, the lithium-ion battery is determined to be in the rapid immersion stage.

[0012] When the rate of change is positive and the value is within a second preset range, the lithium-ion battery is determined to be in a slow immersion stage, wherein the value in the second preset range is less than the value in the first preset range.

[0013] When the capacitance value remains constant or the rate of change is less than a preset threshold, the lithium-ion battery is determined to have reached a wetting equilibrium state.

[0014] The method according to the first embodiment of the present invention further includes:

[0015] The wetting process parameters, including temperature or vacuum degree, are adjusted based on the rate of change.

[0016] When it is determined that the lithium-ion battery has reached the wetting equilibrium state, a wetting completion signal is issued, or the wetting process is stopped.

[0017] According to the method of the first embodiment of the present invention, the correspondence between the changing trend and the wetting state is determined by the following steps:

[0018] Selected lithium-ion batteries were subjected to in-situ electrochemical impedance spectroscopy and in-situ ultrasonic testing simultaneously after electrolyte injection.

[0019] Based on the amplitude, propagation delay, or spectral response parameters of the ultrasonic waves in the in-situ ultrasonic testing results, the degree of immersion of the sample lithium-ion battery at different times is determined.

[0020] Establish a time-dependent mapping relationship between the capacitance value of the transmission line model element and the degree of immersion.

[0021] According to the method of the first embodiment of the present invention, determining the degree of infiltration of the sample lithium-ion battery at different times based on the amplitude, propagation delay, or spectral response parameters of the ultrasonic waves in the in-situ ultrasonic testing results includes:

[0022] The detection area with enhanced ultrasonic wave reflection and increased attenuation was identified as an unwetted area containing pores.

[0023] The detection area where the ultrasonic wave propagation path is stable and the attenuation is reduced is identified as the infiltrated area.

[0024] According to the method of the first embodiment of the present invention, the transmission line model element includes:

[0025] The first impedance orbital and the second impedance orbital characterize the conduction path between the electrode material and the electrolyte;

[0026] Multiple parallel admittance branches connected between the first impedance track and the second impedance track are used to characterize the interface impedance within the electrode pores.

[0027] The capacitance value is extracted from the admittance branch parameters and is used to reflect the degree of contact between the electrode and the electrolyte.

[0028] The method according to the first embodiment of the present invention further includes:

[0029] The validity of the acquired impedance spectrum data was verified using the Kramers-Kronig transformation method.

[0030] Remove impedance spectrum data that failed validity verification.

[0031] A second embodiment of the present invention discloses an electronic device, which includes a memory storing computer-executable instructions and a processor. When the instructions are executed by the processor, the electronic device performs a lithium-ion battery immersion state detection method according to a first embodiment of the present invention.

[0032] A third embodiment of the present invention discloses a computer storage medium storing instructions that, when executed on a computer, cause the computer to perform a method for detecting the immersion state of a lithium-ion battery according to a first embodiment of the present invention.

[0033] A fourth embodiment of the present invention discloses a computer program product including computer-executable instructions, which are executed by a processor to implement a method for detecting the immersion state of a lithium-ion battery according to a first embodiment of the present invention.

[0034] The main differences and effects of the embodiments of the present invention compared with the prior art are as follows:

[0035] In this invention, in-situ electrochemical impedance spectroscopy (EIS) is performed on lithium-ion batteries undergoing liquid injection and wetting to obtain impedance spectrum data that changes with wetting time. The impedance spectrum data is then fitted using a pre-defined equivalent circuit model, which includes transmission line model elements to characterize the impedance properties of porous electrodes. The capacitance values ​​corresponding to these transmission line model elements are extracted from the fitting results. Based on the trend of capacitance value changes with wetting time, the wetting state of the lithium-ion battery is determined. This detection method improves sensitivity and can be performed non-destructively and online. By utilizing in-situ EIS technology combined with a transmission line model, the invisible microscopic wetting process can be transformed into a visualized change in capacitance parameters. This solves the problems of traditional weighing methods being unable to determine internal wetting distribution and infrared thermal imaging methods being greatly affected by environmental interference, providing scientific and accurate data support for optimizing the wetting process and controlling quality in lithium-ion battery production. Attached Figure Description

[0036] Figure 1 A flowchart illustrating a method for detecting the immersion state of a lithium-ion battery according to an embodiment of this application is shown.

[0037] Figure 2 A circuit diagram showing an equivalent circuit model according to an embodiment of this application is provided.

[0038] Figure 3 A time-capacitance graph of a transmission line model element according to an embodiment of this application is shown.

[0039] Figure 4 An ultrasonic imaging diagram of the wetting region inside the battery cell according to an embodiment of this application is shown.

[0040] Figure 5 A circuit diagram of a transmission line model element according to an embodiment of this application is shown.

[0041] Figure 6 This is a hardware structure block diagram of an electronic device implementing the embodiments of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0043] To address the technical problems of existing lithium-ion battery wetting detection methods, such as indirect detection methods, lack of quantitative analysis capabilities, difficulty in revealing the actual internal distribution of the battery cell, and difficulty in achieving online real-time monitoring, embodiments of this application disclose a method for detecting the wetting state of lithium-ion batteries. This method leverages the high sensitivity of electrochemical impedance spectroscopy (EIS) to the electrolyte permeation process in porous electrodes, and combines it with a transmission line model to quantitatively characterize the degree of wetting. Figure 1The flowchart of the method is shown, which includes the following steps:

[0044] S11, perform in-situ electrochemical impedance spectroscopy on the lithium-ion battery during the liquid injection process to obtain impedance spectral data as a function of the injection time.

[0045] In this embodiment, the test object is a lithium-ion battery cell that has completed the electrolyte filling process but is still in the static soaking stage. In-situ electrochemical impedance spectroscopy (In-situ EIS) testing refers to the real-time continuous impedance measurement of the battery cell without disassembling it or damaging its structure. Specifically, the electrolyte-filled battery cell can be connected to an electrochemical workstation, and a small-amplitude sinusoidal AC voltage is applied as a perturbation signal at an open-circuit potential. The amplitude of this perturbation voltage is usually set in the range of 5mV to 10mV. Such a small perturbation will not cause side reactions in the electrode materials or change the internal state of the battery cell, thus ensuring the non-destructive nature of the test. The test frequency range can be set to cover a wide frequency band from high to low frequencies, revealing the impedance characteristics of various physical processes inside the battery (including ion diffusion, charge transfer, electrolyte conductivity, interface polarization, etc.) within different frequency ranges. As the immersion time progresses, the electrolyte gradually penetrates deep into the pores of the electrode, and the impedance characteristics of the cell will change dynamically. By continuously collecting impedance spectra at preset time intervals, a series of time-series impedance spectrum data reflecting the evolution of the internal state of the cell can be obtained.

[0046] S12, the impedance spectrum data is fitted using a preset equivalent circuit model; wherein, the equivalent circuit model includes transmission line model elements used to characterize the impedance characteristics of the porous electrode.

[0047] In this embodiment, a specialized electrochemical equivalent circuit model was established to deduce the physical parameters directly related to wetting from the complex impedance spectrum. For example... Figure 2 As shown, the equivalent circuit model 20 mainly consists of an inductor L1, a first resistor R1, and a transmission line model element M1. The inductor L1 is connected in parallel with the first resistor R1. The transmission line model element M1 (which can be called a Tlmeb element), connected in series with this parallel structure, is the core part of this embodiment. Because the electrodes of a lithium-ion battery have a complex porous structure, the distribution of the electrolyte in the pores is not a uniform planar interface. Traditional simple parallel resistor-capacitor models cannot accurately describe this distribution parameter characteristic. The transmission line model element M1 can accurately fit the impedance characteristics during the wetting process. By fitting the measured impedance spectrum data with the equivalent circuit model 20, the error between the calculated model value and the measured value is minimized, thereby obtaining the parameter values ​​of each element in the model.

[0048] S13, extract the capacitance values ​​corresponding to the transmission line model elements from the fitting results.

[0049] In this embodiment, the transmission line model element M1 includes multiple parameters related to the electrode structure and interface properties, including the capacitance value characterizing the solid-liquid interface. The capacitance value extracted from the fitting parameters of the transmission line model element M1 can directly quantify the degree of electrolyte coverage within the electrode. Specifically, during the fitting process, the capacitance parameter representing the transverse admittance in the transmission line model can be calculated, and the data sequence of this parameter changing over time can be extracted as a basis for determining the wetting state.

[0050] S14. Determine the immersion state of the lithium-ion battery based on the trend of capacitance value change with immersion time; wherein, the rate of increase of capacitance value is positively correlated with the immersion rate of electrolyte inside the lithium-ion battery.

[0051] In this embodiment, the cell's wetting process can be inferred by analyzing the extracted capacitance value change curve over time. Specifically, the capacitance value changes with wetting time in a trend of "fast at first, then slow, and finally stabilizing." By monitoring the rate of change of capacitance value, it is possible to accurately identify whether the cell is currently in a rapid absorption phase, a penetration bottleneck phase, or has reached a fully wetting state.

[0052] The detection method provided in this embodiment improves sensitivity and can be performed non-destructively and online. By utilizing in-situ EIS technology combined with a transmission line model, the invisible microscopic wetting process can be transformed into a visualized change in capacitance parameters. This solves the problems of traditional weighing methods being unable to determine the internal wetting distribution and infrared thermal imaging methods being greatly affected by environmental interference, providing scientific and accurate data support for the optimization of the wetting process and quality control in lithium-ion battery production.

[0053] According to some embodiments of this application, the immersion state of a lithium-ion battery is determined based on the trend of capacitance value change over immersion time, including: monitoring the rate of change of capacitance value over time; determining that the lithium-ion battery is in a rapid immersion stage when the rate of change is positive and the value is within a first preset range; determining that the lithium-ion battery is in a slow immersion stage when the rate of change is positive and the value is within a second preset range, wherein the value in the second preset range is less than the value in the first preset range; and determining that the lithium-ion battery has reached an immersion equilibrium state when the capacitance value remains constant or the rate of change is less than a preset threshold.

[0054] In this embodiment, to achieve automated determination of the immersion state, the first derivative of the capacitance value over time can be calculated, i.e., the rate of change of the capacitance value (dC / dt) can be calculated. For example... Figure 3 As shown, the curve illustrates the variation of capacitance value in transmission line model element M1 with immersion time. The horizontal axis represents time, and the vertical axis represents capacitance value. Based on the magnitude of the rate of change, the immersion process is divided into three characteristic stages. The first stage corresponds to the initial period after liquid injection (e.g., Figure 3The portion of the curve with a steeper slope at the beginning, where the rate of change is in the higher first preset range, indicates that the electrolyte is rapidly occupying the main pore channels of the electrode, defined as the rapid wetting stage. The second stage (e.g.) Figure 3 The section where the slope of the curve becomes gentler in the middle, with the rate of change decreasing to a smaller second preset range, indicates that macroscopic infiltration is basically complete and microscopic pore filling is underway; this is defined as the slow infiltration stage. The third stage (e.g.) Figure 3 When the latter part of the curve tends to be horizontal, the capacitance value basically no longer increases with time, or its tiny fluctuation rate is lower than the preset threshold that can be ignored in engineering, it indicates that the cell has reached saturation, which is defined as the wetting equilibrium state.

[0055] This embodiment divides the wetting stage by setting specific numerical ranges, making the test results more standardized and objective. This helps to quickly screen out products that are not wetted or have not yet completed the wetting process in actual production, avoiding errors from human experience judgment.

[0056] According to some embodiments of this application, it further includes: feedback adjustment of the wetting process parameters based on the rate of change, the wetting process parameters including temperature or vacuum degree; when it is determined that the lithium-ion battery has reached the wetting equilibrium state, issuing a wetting completion signal or stopping the wetting process.

[0057] In this embodiment, the detection method is not only used for passive monitoring but also for active control of the production process, forming a closed-loop feedback. For example, if the rate of change of capacitance value remains low within a predetermined time, it indicates that the wetting speed is too slow. The system can automatically instruct the production equipment to increase the ambient temperature to reduce the electrolyte viscosity or adjust the vacuum level to enhance the capillary penetration driving force, thereby accelerating the wetting process. On the other hand, existing wetting processes often use a fixed settling time (e.g., uniform settling for 24 or 48 hours), which may lead to some cells being "over-wetted" and wasting production capacity, or some cells being "under-wetted" and posing quality risks. Using the method of this embodiment, once the system detects that the capacitance value has entered a stable plateau period, it determines that the cell has reached the wetting equilibrium state and can immediately issue a signal to end the current process and transfer it to the next process such as formation.

[0058] This embodiment directly links the wetting detection results with process control, realizing intelligent management of lithium-ion battery manufacturing. This not only shortens the production cycle and improves production efficiency, but also ensures the consistency of each cell and avoids batch-to-batch quality fluctuations caused by fixed process parameters.

[0059] According to some embodiments of this application, the correspondence between the trend of change and the wetting state is determined by the following steps: Select a sample lithium-ion battery, and simultaneously perform in-situ electrochemical impedance spectroscopy and in-situ ultrasonic testing after liquid injection; determine the degree of wetting of the sample lithium-ion battery at different times based on the amplitude, propagation delay or spectral response parameters of the ultrasonic waves in the in-situ ultrasonic testing results; establish a time-dependent mapping relationship between the capacitance value corresponding to the transmission line model element and the degree of wetting.

[0060] In this embodiment, a "dual in-situ" joint testing method was adopted to determine the physical correspondence between the capacitance parameters in the electrochemical model and the actual wetting state. A typical sample cell was selected, and after liquid injection, it was connected to an electrochemical workstation for EIS testing, while simultaneously using an ultrasonic scanning microscope or transmission probe to perform ultrasonic imaging of the cell. Ultrasonic waves are highly sensitive to changes in density and elastic modulus within materials, and can intuitively display the detected data as the distribution of the liquid. By comparing the EIS data and ultrasonic images acquired at the same time point, a strong correlation between the two can be established. For example, as... Figure 3 and Figure 4 The experimental results shown are as follows: Within 0-18 hours, in-situ EIS results show that the capacitance value of element M1 in the transmission line model increases rapidly, while the concurrent in-situ ultrasonic results show the wetting area inside the cell ( Figure 4 The capacitance value (displayed as dark in the image) expands rapidly; within 18-36 hours, the accumulation rate of the capacitance value displayed by EIS slows down, and the corresponding changes in the infiltrated area shown by the ultrasound image become subtle; after 36 hours, the capacitance value hardly changes anymore, and the ultrasound image also remains almost stable.

[0061] This embodiment utilizes visualized ultrasonic testing technology as preliminary verification and calibration, effectively calibrating the physical meaning of electrochemical impedance spectroscopy characteristic parameters, and determining the correspondence between the capacitance value in transmission line model element M1 and the actual wetting condition of the battery cell, thereby improving the reliability and scientific rigor of the testing method.

[0062] According to some embodiments of this application, the degree of wetting of a sample lithium-ion battery at different times is determined based on the amplitude, propagation delay, or spectral response parameters of the ultrasonic waves in the in-situ ultrasonic testing results. This includes: determining the detection area where ultrasonic wave reflection is enhanced and attenuation is increased as an unwetted area with pores; and determining the detection area where the ultrasonic wave propagation path is stable and attenuation is reduced as a wetted area.

[0063] In this embodiment, the principle of determining the degree of wetting using ultrasound is utilized. Ultrasound is a mechanical wave, and its propagation characteristics vary greatly in different media. In the unwetted area, the pores of the electrode and diaphragm are filled with gas. The difference in acoustic impedance between the gas and the solid particles is extremely large, causing strong scattering and reflection of ultrasound waves at the interface, resulting in a sharp attenuation of transmitted energy. This typically manifests as a high-reflection, low-transmission characteristic area in ultrasound imaging (e.g., Figure 4 The light-colored central region at time 0h). In the infiltrated region, the pores are filled with electrolyte, the acoustic impedance matching between the liquid and the solid is good, the ultrasound can penetrate well, the propagation path is stable, and the signal attenuation is significantly reduced. In the imaging image, this is a characteristic region with high transmission and uniform signal (e.g.). Figure 4 (Large dark areas appear at 36 hours and beyond). The current level of infiltration can be quantified by calculating the proportion of the high-transmittance area to the total area.

[0064] This embodiment utilizes the sensitivity of ultrasound to the gas-liquid interface to provide an intuitive and one-time preliminary physical calibration, which further supports the accuracy of judging the wetting state based on EIS capacitance value. This enables subsequent non-destructive and rapid electrical testing to replace expensive and complex ultrasonic testing for production line monitoring.

[0065] According to some embodiments of this application, the transmission line model element includes: a first impedance track and a second impedance track, characterizing the conduction path between the electrode material and the electrolyte; a plurality of parallel admittance branches connected between the first impedance track and the second impedance track, used to characterize the interface impedance within the electrode pores; wherein, the capacitance value is extracted from the admittance branch parameters and used to reflect the degree of contact between the electrode sheet and the electrolyte.

[0066] In this embodiment, the internal microstructure of the transmission line model element M1 is further provided. For example... Figure 5 As shown, the model employs a trapezoidal network structure with distributed parameters to simulate the physical characteristics of porous electrodes. Specifically, the model includes a first impedance orbital Z1 and a second impedance orbital Z2. The first impedance orbital Z1 consists of multiple first impedance units X1 connected in series, and the second impedance orbital Z2 consists of multiple second impedance units X2 connected in series. Physically, the first impedance unit X1 and the second impedance unit X2 represent the electron transport impedance between solid-phase active material particles and the lithium ion migration impedance in the porous liquid electrolyte, respectively.

[0067] like Figure 5 As shown, multiple parallel admittance branches Y are connected between the corresponding nodes of the first impedance track Z1 and the second impedance track Z2. Figure 5(Identified as a double-arrow element). These admittance branches Y are distributed along the transmission line and are used to characterize the local interface impedance at different depths from the orifice to the bottom. Each admittance branch Y may contain interfacial double-layer capacitance and charge transfer resistance. When the electrolyte is not fully wetted, some admittance branches Y are in an inactive or high-impedance state; as wetting progresses, more admittance branches Y are connected by the electrolyte. The capacitance value extracted in the steps of the aforementioned embodiments is the total effective capacitance calculated based on the capacitive parameters in these admittance branches Y.

[0068] Specifically, the transmission line model element M1 is configured with specific boundary conditions to simulate the actual physical interface of the porous electrode in a lithium-ion battery:

[0069] At the first end of the trapezoidal network (i.e. Figure 5 (Left side of the image, corresponding to the current collector side interface of the electrode).

[0070] The first terminal T1 serves as an electron injection port and is electrically connected to the first impedance track Z1, allowing the electron flow of the test signal to enter the solid-phase active material. The second terminal T2, the third terminal T3, and the second impedance unit X2 shown by the dashed line at this terminal are configured in an ion-blocking state (equivalent to an open circuit) to characterize the physical property that the current collector does not have ion conduction capability and lithium ions cannot pass through the current collector interface.

[0071] At the second end of the trapezoidal network (i.e. Figure 5 (Right side of the image, corresponding to the membrane / electrolyte side interface of the electrode).

[0072] The sixth terminal T6 serves as an ion exchange port and is electrically connected to the second impedance track Z2, allowing lithium ions to exchange with the external bulk electrolyte. The fourth terminal T4, the fifth terminal T5, and the first impedance unit X1 shown by the dashed line at this terminal are configured in an electron-blocking state (equivalent to an open circuit) to characterize the physical property that the membrane has electronic insulation, preventing electrons in the solid phase from passing through this interface into the electrolyte.

[0073] The transmission line model element in this embodiment can accurately determine the capacitance value reflecting the solid-liquid contact area, thereby achieving non-destructive, real-time, and quantitative assessment of the cell's immersion state. This effectively solves the problems of low accuracy or high destructiveness of existing detection methods, enabling precise guidance of production processes, shortening settling time, and significantly improving battery manufacturing efficiency and product consistency.

[0074] According to some embodiments of this application, the method further includes: validating the acquired impedance spectrum data using the Kramers-Kronig conversion method; and removing impedance spectrum data that fails the validity verification.

[0075] In this embodiment, considering that cell immersion is a dynamic process and EIS testing requires a certain amount of time (especially at low frequencies), data quality checks are necessary to ensure that the system meets the requirements of linearity, causality, and stability during testing. Specifically, the KK verification function built into professional simulation software can be used. If the deviation between the measured data and the KK conversion data exceeds a preset range, it indicates that the cell state fluctuated drastically or was subject to external interference at the moment of testing. This data point no longer meets the basic premise of impedance analysis and should be discarded to avoid misleading subsequent fitting results.

[0076] This embodiment introduces a data validity verification step to eliminate abnormal data caused by system non-steady state or noise, ensuring the high quality of impedance spectrum data used for fitting, thereby further improving the accuracy and robustness of wetting state judgment.

[0077] Figure 6 This is a hardware structure block diagram of an electronic device implementing the embodiments of this application.

[0078] like Figure 6 As shown, the electronic device 600 may include one or more processors 602, a system motherboard 608 connected to at least one of the processors 602, system memory 604 connected to the system motherboard 608, non-volatile memory (NVM) 606 connected to the system motherboard 608, and a network interface 610 connected to the system motherboard 608.

[0079] Processor 602 may include one or more single-core or multi-core processors. Processor 602 may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors, baseband processors, etc.). In embodiments of the invention, processor 602 may be configured to perform one or more embodiments according to various embodiments of this application.

[0080] In some embodiments, system motherboard 608 may include any suitable interface controller to provide any suitable interface to at least one of processors 602 and / or any suitable device or component communicating with system motherboard 608.

[0081] In some embodiments, system motherboard 608 may include one or more memory controllers to provide an interface to system memory 604. System memory 604 may be used to load and store data and / or instructions. In some embodiments, system memory 604 of electronic device 600 may include any suitable volatile memory, such as suitable dynamic random access memory (DRAM).

[0082] The NVM 606 may include one or more tangible, non-transitory computer-readable media for storing data and / or instructions. In some embodiments, the NVM 606 may include any suitable non-volatile memory such as flash memory and / or any suitable non-volatile storage device, such as at least one of an HDD (Hard Disk Drive), a CD (Compact Disc) drive, or a DVD (Digital Versatile Disc) drive.

[0083] The NVM 606 may include a portion of the storage resources on a device installed on electronic device 600, or it may be accessible by the device, but is not necessarily part of the device. For example, the NVM 606 may be accessed over a network via network interface 610.

[0084] Specifically, system memory 604 and NVM 606 may each include a temporary copy and a permanent copy of instruction 620. Instruction 620 may include instructions that, when executed by at least one of processors 602, cause electronic device 600 to perform methods as described in any embodiment of this application. In some embodiments, instruction 620, hardware, firmware, and / or its software components may additionally / alternatively be located in system motherboard 608, network interface 610, and / or processor 602.

[0085] Network interface 610 may include a transceiver for providing a radio interface to electronic device 600, thereby enabling communication with any other suitable device (e.g., front-end module, antenna, etc.) via one or more networks. In some embodiments, network interface 610 may be integrated into other components of electronic device 600. For example, network interface 610 may be integrated into at least one of processor 602, system memory 604, NVM 606, and firmware device (not shown) with instructions, wherein when at least one of processor 602 executes the instructions, electronic device 600 implements one or more embodiments of various embodiments of this application.

[0086] The network interface 610 may further include any suitable hardware and / or firmware to provide a multiple-input multiple-output radio interface. For example, the network interface 610 may be a network adapter, a wireless network adapter, a telephone modem, and / or a wireless modem.

[0087] In one embodiment, at least one of the processors 602 may be packaged together with one or more controllers for the system motherboard 608 to form a system-in-package (SiP). In another embodiment, at least one of the processors 602 may be integrated on the same die with one or more controllers for the system motherboard 608 to form a system-on-a-chip (SoC).

[0088] The electronic device 600 may further include an input / output (I / O) device 612 connected to the system motherboard 608. The I / O device 612 may include a user interface enabling a user to interact with the electronic device 600; the peripheral component interface is designed to allow peripheral components to also interact with the electronic device 600. In some embodiments, the electronic device 600 may also include sensors for determining at least one type of environmental condition and location information related to the electronic device 600.

[0089] In some embodiments, I / O device 612 may include, but is not limited to, a display (e.g., a liquid crystal display, a touch screen display, etc.), a speaker, a microphone, one or more cameras (e.g., a still image camera and / or a video camera), a flashlight (e.g., a light-emitting diode flash) and a keyboard.

[0090] In some embodiments, the peripheral component interface may include, but is not limited to, a non-volatile memory port, an audio jack, and a power interface.

[0091] In some embodiments, the sensor may include, but is not limited to, a gyroscope sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of or interact with the network interface 610 to communicate with components of the positioning network, such as Global Positioning System (GPS) satellites.

[0092] It is understood that the structures illustrated in the embodiments of the present invention do not constitute a specific limitation on the electronic device 600. In other embodiments of this application, the electronic device 600 may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.

[0093] Program code can be applied to input instructions to perform the functions described in this invention and generate output information. The output information can be applied to one or more output devices in a known manner. For the purposes of this application, a system for processing instructions including processor 602 includes any system having a processor such as a digital signal processor (DSP), microcontroller, application-specific integrated circuit (ASIC), or microprocessor.

[0094] The program code can be implemented using a high-level procedural language or an object-oriented programming language to communicate with the processing system. Assembly language or machine language can also be used when needed. In fact, the mechanisms described in this invention are not limited to any particular programming language. In either case, the language can be a compiled language or an interpreted language.

[0095] One or more aspects of at least one embodiment can be implemented by instructions stored on a computer-readable storage medium, which, when read and executed by a processor, enable an electronic device to implement the methods of the embodiments described in this invention.

[0096] According to some embodiments of this application, a computer storage medium is disclosed, on which instructions are stored, which, when executed on a computer, cause the computer to perform a method for detecting the immersion state of a lithium-ion battery according to embodiments of this application.

[0097] The method embodiments of this application correspond to this embodiment, and this embodiment can be implemented in conjunction with the method embodiments of this application. The relevant technical details mentioned in the method embodiments of this application are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the method embodiments of this application.

[0098] According to some embodiments of this application, a computer program product is disclosed, including computer-executable instructions that are executed by a processor to implement a method for detecting the immersion state of a lithium-ion battery according to embodiments of this application.

[0099] The method embodiments of this application correspond to this embodiment, and this embodiment can be implemented in conjunction with the method embodiments of this application. The relevant technical details mentioned in the method embodiments of this application are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the method embodiments of this application.

[0100] It is understood that the specific embodiments described herein are merely for illustrative purposes and not for limiting the scope of this application. Furthermore, for ease of description, the accompanying drawings show only the parts relevant to this application, and not all of the structures or processes. It should be noted that similar reference numerals and letters in the drawings denote similar items throughout this application.

[0101] It should be understood that although the terms "first," "second," etc., may be used herein to describe various features, these features should not be limited by these terms. The use of these terms is merely for distinction and should not be construed as indicating or implying relative importance. For example, without departing from the scope of the exemplary embodiments, a first feature may be referred to as a second feature, and similarly, a second feature may be referred to as a first feature.

[0102] In the description of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0103] The illustrative embodiments of this application include, but are not limited to, methods, apparatus, media, and computer program products for detecting the immersion state of lithium-ion batteries.

[0104] Various aspects of the illustrative embodiments will be described using terminology commonly employed by those skilled in the art to convey the essence of their work to others skilled in the art. However, it will be apparent to those skilled in the art that some alternative embodiments will be practiced using the features partially described. Specific figures and configurations are set forth for purposes of explanation in order to provide a more thorough understanding of the illustrative embodiments. However, it will be apparent to those skilled in the art that alternative embodiments may be practiced without specific details. In some other instances, well-known features have been omitted or simplified herein to avoid obscuring the illustrative embodiments of this application.

[0105] Furthermore, the various operations will be described as multiple separate operations in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations must depend on the order of description, and many of these operations may be performed in parallel, concurrently, or simultaneously. Moreover, the order of the operations may also be rearranged. The process may be terminated when the described operations are completed, but may also include additional steps not included in the figures. The process may correspond to a method, function, procedure, subroutine, subroutine, etc.

[0106] References to "an embodiment," "embodiment," "illustrative embodiment," etc., in this application indicate that the described embodiment may include specific features, structures, or properties; however, each embodiment may or may not necessarily include specific features, structures, or properties. Furthermore, these phrases are not necessarily directed at the same embodiment. Moreover, when specific features are described in conjunction with specific embodiments, the knowledge of those skilled in the art can influence the combination of these features with other embodiments, whether or not those embodiments are explicitly described.

[0107] Unless the context otherwise specifies, the terms “comprising,” “having,” and “including” are synonyms. The phrase “A and / or B” means “(A), (B), or (A and B).”

[0108] As used herein, the term "module" may refer to, as part of, or include: a memory (shared, dedicated, or grouped), an application-specific integrated circuit (ASIC), electronic circuitry and / or a processor (shared, dedicated, or grouped), combinational logic circuitry, and / or other suitable components that provide the said functionality for running one or more software or firmware programs.

[0109] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order is not necessary. Rather, in some embodiments, these features may be illustrated in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular drawing does not mean that all embodiments need to include such features; in some embodiments, these features may be omitted or may be combined with other features.

[0110] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions or programs carried or stored on one or more transient or non-transient machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors, etc. When the instructions or program are run by a machine, the machine may perform the various methods described above. For example, the instructions may be distributed via a network or other computer-readable media. Therefore, machine-readable media may include, but are not limited to, any mechanism for storing or transmitting information in a machine-readable (e.g., computer-readable) form, such as floppy disks, optical disks, optical disc read-only memories (CD-ROMs), magneto-optical disks, read-only memories (ROMs), random access memories (RAMs), erasable programmable read-only memories (EPROMs), electronically erasable programmable read-only memories (EEPROMs), magnetic cards or optical cards, or flash memory or tangible machine-readable storage for transmitting network information via electrical, optical, acoustic, or other forms of signals (e.g., carrier waves, infrared signals, digital signals, etc.). Therefore, machine-readable media includes any form of machine-readable medium suitable for storing or transmitting electronic instructions or machine-readable (e.g., computer-readable) information.

[0111] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, the use of the technical solutions of this application is not limited to the various applications mentioned in the embodiments of this application. Various structures and modifications can be easily implemented with reference to the technical solutions of this application to achieve the various beneficial effects mentioned herein. Within the scope of knowledge possessed by those skilled in the art, all changes made without departing from the spirit of this application should be considered within the scope of this patent application.

Claims

1. A method for detecting the wetting state of a lithium-ion battery, characterized in that, include: In-situ electrochemical impedance spectroscopy was performed on lithium-ion batteries during the liquid injection process to obtain impedance spectral data as a function of the injection time. The impedance spectrum data is fitted using a preset equivalent circuit model; wherein, the equivalent circuit model includes transmission line model elements for characterizing the impedance characteristics of the porous electrode. Extract the capacitance values ​​corresponding to the transmission line model elements from the fitting results; The immersion state of the lithium-ion battery is determined based on the trend of the capacitance value changing with immersion time; wherein the rate of increase of the capacitance value is positively correlated with the immersion rate of the electrolyte inside the lithium-ion battery.

2. The method according to claim 1, characterized in that, Determining the immersion state of the lithium-ion battery based on the trend of the capacitance value changing with immersion time includes: Monitor the rate of change of the capacitance value over time; When the rate of change is positive and the value is within the first preset range, the lithium-ion battery is determined to be in the rapid immersion stage. When the rate of change is positive and the value is within a second preset range, the lithium-ion battery is determined to be in a slow immersion stage, wherein the value in the second preset range is less than the value in the first preset range. When the capacitance value remains constant or the rate of change is less than a preset threshold, the lithium-ion battery is determined to have reached a wetting equilibrium state.

3. The method according to claim 2, characterized in that, Also includes: The wetting process parameters, including temperature or vacuum degree, are adjusted based on the rate of change. When it is determined that the lithium-ion battery has reached the wetting equilibrium state, a wetting completion signal is issued, or the wetting process is stopped.

4. The method according to claim 1, characterized in that, The correspondence between the changing trend and the immersion state is determined through the following steps: Selected lithium-ion batteries were subjected to in-situ electrochemical impedance spectroscopy and in-situ ultrasonic testing simultaneously after electrolyte injection. Based on the amplitude, propagation delay, or spectral response parameters of the ultrasonic waves in the in-situ ultrasonic testing results, the degree of immersion of the sample lithium-ion battery at different times is determined. Establish a time-dependent mapping relationship between the capacitance value of the transmission line model element and the degree of immersion.

5. The method according to claim 4, characterized in that, The determination of the degree of immersion of the lithium-ion battery sample at different times based on the amplitude, propagation delay, or spectral response parameters of the ultrasonic waves in the in-situ ultrasonic testing results includes: The detection area with enhanced ultrasonic wave reflection and increased attenuation was identified as an unwetted area containing pores. The detection area where the ultrasonic wave propagation path is stable and the attenuation is reduced is identified as the infiltrated area.

6. The method according to claim 1, characterized in that, The transmission line model elements include: The first impedance orbital and the second impedance orbital characterize the conduction path between the electrode material and the electrolyte; Multiple parallel admittance branches connected between the first impedance track and the second impedance track are used to characterize the interface impedance within the electrode pores. The capacitance value is extracted from the admittance branch parameters and is used to reflect the degree of contact between the electrode and the electrolyte.

7. The method according to claim 1, characterized in that, Also includes: The validity of the acquired impedance spectrum data was verified using the Kramers-Kronig transformation method. Remove impedance spectrum data that failed validity verification.

8. An electronic device, characterized in that, The electronic device includes a memory storing computer-executable instructions and a processor, which, when executed by the processor, cause the electronic device to perform the method for detecting the immersion state of a lithium-ion battery according to any one of claims 1-7.

9. A computer storage medium, characterized in that, The computer storage medium stores instructions that, when executed on the computer, cause the computer to perform the method for detecting the immersion state of a lithium-ion battery according to any one of claims 1-7.

10. A computer program product, characterized in that, It includes computer-executable instructions, which are executed by a processor to implement a method for detecting the immersion state of a lithium-ion battery according to any one of claims 1-7.

Images